LIDINE 2023: LIght Detection In Noble Elements




LIDINE 2023: LIght Detection In Noble Elements



Madrid at night

The objective of the LIDINE conference series is to promote discussion among members of the particle and nuclear physics communities about detector technologies based on noble elements and their applications such as dark matter, neutrino oscillations, solar and supernova neutrinos, coherent elastic neutrino-nucleus scattering, neutrinoless double-beta decay, neutron EDM, and medical physics.

LIDINE 2023 is an in-person conference, hosted in the School of Mines and Energy EngineeringMadrid (Spain), by CIEMAT, DIPC, CAPA/UNIZAR, IGFAE/USC and LSC-Canfranc, on September 20-22, 2023.

The conference is organized along the following tracks:

  • Light/charge response in Noble Elements (gas, liquid, dual phase)
  • Light/charge readout (PMTs, SiPM, WLS, electronics, etc.)
  • Detector techniques (HV, cryogenics, purification, calibration, etc.)
  • Signal reconstruction and identification (analysis methods, simulations)
  • Applications (dark matter, neutrino, precision frontier, medicine, etc.)

Conference fee:

The conference fee is 250 € if paid by July 29th, and 300 € when paid after that date. The price includes the coffee breaks and lunches. A supplement of 50 € will be included in the registration fee for those attending the conference dinner. Details on payment will be sent by email once registration is completed.

Important deadlines:

  • Abstract Submission: July 16th.
  • Early registration (including payment of the conference fee of 250 €): July 29th.
  • Late registration (including payment of the conference fee of 300 €): September 8th.
  • Conference proceedings submission:  November 30th.

International Scientific Committee:

  • Nicola Canci (INFN Napoli)
  • Theresa Fruth (Univ. of Sidney)
  • Marcin Kuźniak (AstroCeNT)
  • Qing Lin (Univ. of Science and Technology of China)
  • Ana Amelia Machado  (Campinas State Univ.)
  • Kaixuan Ni (UC San Diego)
  • Tina Pollmann (Nikhef/Univ. of Amsterdam)
  • Roberto Santorelli (CIEMAT) - Chair
  • Marco Selvi (INFN, Bologna)
  • Andrzej Szelc (Univ. of Edinburgh)
  • Denver Whittington (Syracuse Univ.)

Local Organising Committee:

  • Susana Cebrián (CAPA/Univ. of Zaragoza)
  • Pilar Coca (CIEMAT) - Secretary
  • Paola Ferrario (Donostia International Physics Center/Ikerbasque)
  • Pablo García Abia (CIEMAT)
  • Diego González Díaz (IGFAE/Univ. Santiago de Compostela)
  • Gloria Luzón (CAPA/Univ. of Zaragoza)
  • María Martínez (CAPA/Univ. of Zaragoza)
  • Francesc Monrabal (Donostia International Physics Center)
  • Joaquim Palacio Navarro (Canfranc Underground Laboratory, LSC)
  • Carmen Palomares (CIEMAT)
  • Vicente Pesudo (CIEMAT)
  • Roberto Santorelli (CIEMAT)

Note: in order to submit an abstract, you shall register on the CIEMAT Indico.

  • Alessio Caminata
  • Alexander Bismark
  • Ana Amelia Machado
  • Ana Paula Mendonça
  • Ander Simón Estévez
  • Andrea Ficorella
  • Andrea Zani
  • Andreas Leonhardt
  • André Cortez
  • Anna Heggestuen
  • Armando Francesco Borghesani
  • Auke Colijn
  • Austin de St Croix
  • Azam Zabihi
  • Bruno Gelli
  • Carla Maria Cattadori
  • Carlos Henriques
  • Carmen Palomares
  • Christoph Vogl
  • Clea Sunny
  • Daniel Díaz Mairena
  • Darcy Newmark
  • David José Gaspar Marques
  • Diego Gonzalez-Diaz
  • Diego Ramírez García
  • Dominique Thers
  • Douglas Fields
  • Emma Ellingwood
  • Evan Angelico
  • Fei Gao
  • Francesc Monrabal
  • Francesco Di Capua
  • Francisco Javier Nicolas-Arnaldos
  • Gabriel Botogoske
  • Gloria Luzón Marco
  • Gonzalo Martínez Lema
  • Hector Mirallas
  • Iftikhar Ahmad
  • Jacob Bargemann
  • Jianyang Qi
  • Jiaoyang/娇瑒 Li/李
  • Joaquim Palacio Navarro
  • Jonas Bürgi
  • Juan Ignacio Larruquert
  • Kaixuan Ni
  • Kelsey Oliver-Mallory
  • Laura Pérez Molina
  • Ludovico Luzzi
  • Mani Tripathi
  • Marcin Kuźniak
  • Marek Walczak
  • Maria Cecilia Bazetto
  • Maria Martinez
  • Marta Babicz
  • Matteo Saviozzi
  • Maximilian Goldrunner
  • Michael Keller
  • Michal Olszewski
  • Miguel Cárdenas Montes
  • Nerea Salor Iguiñiz
  • Neus López March
  • Nicola Canci
  • Noemi Pino
  • Pablo Amedo Martinez
  • Pablo García Abia
  • Paola Ferrario
  • Paolo Franchini
  • Patricia Sanchez-Lucas
  • Paules Zakhary
  • Prashansa Mukim
  • Robert Hammann
  • Roberto Santorelli
  • Rodrigo Alvarez Garrote
  • Saúl Domínguez Negreira
  • Scott Kravitz
  • Shawn Westerdale
  • Stefano Roberto Soleti
  • Susana Cebrian
  • Tina Pollmann
  • Tom Kresse
  • Valentina Cocco
  • Vicente Pesudo Fortes
  • Víctor Bernardo Puente
    • 1
      Registration Auditorium


    • 2
      Introduction Auditorium


      Speaker: Roberto Santorelli (CIEMAT)
    • Session I Auditorium


      Convener: Roberto Santorelli (CIEMAT)
      • 3
        First science run results of XENONnT

        The XENONnT detector, located at Laboratori Nazionali del Gran Sasso, in Italy, utilizes 5.9 tonnes of instrumented liquid xenon in the direct search for weakly-interacting massive particle (WIMP) dark matter. Having achieved unprecedented levels of target purity in both electronegative contaminants and intrinsic radioisotopes, it is sensitive to a plethora of signals beyond WIMPs, such as solar axions, axion-like particles, bosonic dark matter and solar neutrinos. This talk will present an overview of the experiment and its performance, along with the results from its first science run.

        Speaker: Diego Ramírez García (University of Zurich)
      • 4
        Status of the LUX-ZEPLIN (LZ) experiment’s search for dark matter

        LUX-ZEPLIN (LZ) is a dark matter direct detection experiment nearly a mile underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. LZ employs a dual-phase xenon time projection chamber with 7 tonnes of active volume and a multi-component veto system for sensitive detection of particles such as Weakly Interacting Massive Particles (WIMPs), a highly motivated dark matter candidate. This presentation will give the status of the LZ experiment and its search for WIMP dark matter as well as recent studies of other new physics phenomena.

        Speaker: Prof. Scott Kravitz (The University of Texas at Austin)
      • 5
        The DarkSide 20k Experiment

        The DarkSide-20k experiment represents the present goal of the Global Argon Dark Matter Collaboration program. Bringing together the success of the DarkSide-50 detector and the experience gained on large volume membrane cryostats developed within the DUNE program, the community is now building a dual-phase LAr-TPC equipped with SiPM matrices for light readout. The main goal of the experiment is to discover or to extend the current sensitivity limits on the search for dark matter WIMP-like particles.
        Currently, the experiment has entered the implementation phase and the external cryostat is being put in place at Laboratori Nazionali del Gran Sasso (LNGS), Italy. The detector construction will follow, and data taking is expected to start in late 2026.
        This contribution will introduce the DarkSide detector and goals, and it will report on the ongoing construction of the underground infrastructure at LNGS. Finally, it will concentrate on the current activities of characterization of the Silicon wafers that are at the base of the construction of the detector light readout system.

        Speaker: Andrea Zani
      • 6
        Status and prospects of the DEAP-3600 experiment

        DEAP-3600 is the largest running dark matter detector filled with liquid argon, set at SNOLAB, in Sudbury, Canada, 2 km underground. The experiment holds the most stringent exclusion limit in non-Xe target for WIMPs above 10 GeV/c$^2$.

        In the published analysis the main background reducing the sensitivity were events induced by alpha particles in some surfaces and in suspended dust. I will describe the general status of the experiment, focusing on these background sources and present the status of both the hardware upgrades and the multivariate analysis developed to decrease their impact and eventually improve the detector sensitivity in the upcoming WIMP search.

        Speaker: Vicente Pesudo Fortes (CIEMAT)
    • 10:40 AM
      Coffee & tea break Colonnade room

      Colonnade room

    • Session II Auditorium


      Convener: María Martínez (CAPA/Univ. of Zaragoza)
      • 7
        The DEAP-3600 liquid argon optical model

        As liquid argon (LAr) detectors are made at progressively larger sizes, accurate models of LAr optical properties become increasingly important for simulating light transport, understanding signals, and developing analyses. The refractive index, group velocity, and Rayleigh scattering length are particularly important for VUV and visible photons in detectors with diameters much greater than one meter. While optical measurements in the VUV are sparse, recent measurements of the group velocity of 128 nm photons in LAr provide valuable constraints on these parameters. These calculations are further complicated by the dependence of optical parameters on thermodynamic properties that might fluctuate or vary throughout the argon volume. This talk presents the model used by DEAP-3600, a dark matter direct detection experiment at SNOLAB using a 3.3 tonne LAr scintillation counter. Existing data and thermodynamic models are synthesized to estimate the wavelength-dependent refractive index, group velocity, and Rayleigh scattering length within the detector, and parameters' uncertainties are estimated. This model, along with in situ measurements of LAr scintillation properties, is benchmarked against data collected in DEAP-3600, providing a method for modeling optical properties in large LAr detectors and for propagating their uncertainties through downstream simulations.

        Speaker: Shawn Westerdale (INFN Cagliari)
      • 8
        Neutron tagging with Gd-loaded PMMA

        DarkSide-20k is a direct dark matter search experiment, that looks for Weakly Interacting Massive Particle (WIMP) events. The detector is based on an ultrapure liquid Argon double-phase Time Projection Chamber, which will be located at Laboratori Nazionali del Gran Sasso. In rare event search experiments (like the DarkSide case), it is crucial to keep under control any background sources. In particular, one of the most dangerous background sources are neutrons, which could induce nuclear recoils, producing a signal indistinguishable from that of the WIMPs. The strategy adopted in the DarkSide-20k experiment is to build a neutron veto detector, made of a thick plastic layer containing gadolinium, which has a high neutron capture cross section. The construction of 17 cm thick plates made of polymethylmethacrylate (PMMA) doped with a compound containing gadolinium was therefore adopted. The choice of PMMA is due to the high hydrogen content of this polymer, to moderate the neutrons. Then thermal neutrons will be captured on the gadolinium nuclei and will be revealed, exploiting the subsequent emission of an easily-detectable high energy γ ray cascade in the surrounding liquid Argon. All the components of the composite material must be screened to identify any traces of elements (such as uranium, thorium and potassium) whose descendant radioactive isotopes could affect the performance of the experiment. The DarkSide collaboration has developed two strategies for the realisation of gadolinium doped PMMA sheets, using two gadolinium-containing compounds: Gadolinium methacrylate and gadolinium oxide in the form of nanograins and the first strategy has been chosen for the construction of DS-20k detector. The contribution reviews the innovative working principle of the DarkSide-20k veto and the development of these innovative materials focusing especially on the gadolinium oxide strategy.

        Speaker: Alessio Caminata (INFN-Genoa)
      • 9
        Advancing Liquid Xenon Dark Matter Detection with DARWIN observatory

        DARWIN (DARk matter WImp search with liquid xenoN) is an upcoming experiment designed to address the enigmatic nature of dark matter and neutrinos. With a 40-tonne liquid xenon sensitive target, DARWIN aims to explore the entire accessible parameter space down to the neutrino floor limitation for Weakly Interacting Massive Particles (WIMPs). Moreover, this low-background, low-threshold astroparticle observatory offers a broad physics program beyond dark matter searches. With its large active target, DARWIN can explore solar neutrinos, axion and axion-like particles, and neutrinoless double beta decay of $^{136}$Xe. The DARWIN project is supported by the XLZD consortium, which includes XENONnT and LZ collaborations. If realised within XLZD, the new design baseline, a 60-tonne liquid xenon sensitive target, will further enhance DARWIN’s sensitivity. In this talk, I will provide an overview of DARWIN, highlighting its scientific reach and key research and development efforts.

        Speaker: Marta Babicz (University of Zurich)
      • 10
        Xenoscope and photosensor R&D for DARWIN at UZH

        The DARWIN observatory is a proposed multi-purpose experiment for dark matter and neutrino physics, featuring a 50 tonne (40 tonnes active) dual-phase xenon time projection chamber. To test key technological concepts required for the realization of DARWIN, we built Xenoscope at the University of Zurich, a full-scale vertical demonstrator using 400 kg of liquid xenon (LXe). It will be used as a first-time demonstration of electron drift in LXe over 2.6 m, as well as to study electron cloud diffusion and measure LXe optical properties. To investigate novel candidate photosensors for DARWIN, we further characterize the performance of Hamamatsu R12699-406-M4 flat panel photomultiplier tubes in xenon at our test facility MarmotX. We present an overview of the Xenoscope facility, current and planned measurement campaigns, as well as first R12699 PMT characterization results.

        Speaker: Alexander Bismark (University of Zurich)
      • 11
        The DarkSide-20k underground argon procurement chain

        The DarkSide-20k experiment searches for dark matter by looking for interactions of WIMPs in a 50 tonnes target of liquid argon using double-phase time projection chamber technology. The key component of the experiment is low radioactivity argon depleted in the isotope Ar.
        The supply chain begins with the Urania plant in Colorado, which can produce argon at a purity of 99.99% from a CO stream sourced from a deep well that reaches the Earth’s mantle, at a rate of about 250 kg/day. The plant, which includes four distillation columns and a pressure swing absorption stage, has already been fabricated while the site is being prepared for installation. After this initial purification stage, the argon will be transported to Sardinia, Italy, where the Aria plant, based on a 350 m cryogenic distillation column, will further suppress impurities by several orders of magnitude. The Aria plant has already been fully fabricated and is now in the installation phase. A lower version, about
        26 m high, has been tested over the last three years with very positive results confirming the cryogenic distillation technology.
        The importance of this supply chain and of associated techniques extends well beyond DarkSide-20k. Low-radioactivity argon is also of interest for the LEGEND-1000 experiment and for the ultimate dark-matter search experiment using argon ARGO and is attracting the attention of the DUNE collaboration for its Module of Opportunity.

        Speaker: Valentina Cocco (Universita' e INFN Cagliari, Italy)
      • 12
        Monitoring 39Ar Background for DarkSide-20k with DArTinArDM

        Assessing the purity of the underground argon in terms of Ar-39 is crucial to ensure the successful operation of DarkSide-20k (DS-20k), a next-generation dark matter detector under construction by the Global Argon Dark Matter Collaboration (GADMC). To achieve this goal, the GADMC is constructing the DArTinArDM experiment at the LSC laboratory in Spain.

        The radiopure DArT chamber (~1 liter), filled with underground argon, will be placed in the center of the ArDM detector. With ~1 ton atmospheric argon, ArDM will act as an active veto. DArTinArDM is designed to measure the Ar-39 depletion factor in the underground argon with a sensitivity grater than 0.1 mBq/kg. This measurement will be performed on small quantities from every batch of UAr guaranteeing that their radiopurity meets the requirements before filling DS-20k.

        The DArT chamber is currently operating underground at LSC in a test cryostat, for the purpose of establishing hardware and software operation protocols, optimizing the setup's operating conditions, and developing analysis tools.

        In parallel, the ArDM detector has been refurbished with a new passive shield and a new light detection system to minimize background events and consequently improve its sensitivity.

        In this talk, I will provide an overview of the current status and prospects of the DArTinArDM project.

        Speaker: Daniel Díaz Mairena (CIEMAT)
      • 13
        Study of cosmogenic activation above ground of Argon for DarkSide-20k

        The use of large amounts of low-radioactivity Argon is envisaged in the context of different projects related to rare event searches like the direct detection of dark matter or neutrino studies.
        Material activation due to exposure to cosmic rays may become an important background source for experiments investigating these phenomena.
        In the case of DarkSide-20k, the extraction and purification of 120 tons of underground Ar (UAr) depleted in 39Ar is foreseen. Cosmogenic yields of relevant induced long-lived radioisotopes have been estimated to set the requirements and procedures during the preparation of the experiment; production rates, either measured or calculated, have been considered. The activity of 39Ar induced during extraction, purification and transport on surface is evaluated to be 2.8% of the activity measured in UAr by DarkSide-50 experiment, which used the same underground source, and thus considered acceptable. Other isotopes in the UAr such as 37Ar and 3H are shown not to be relevant due to short half-life and the assumed purification methods. The results of this study can be useful to set limits on exposure for the procurement of radiopure UAr in future LAr projects.

        Speaker: Susana Cebrian (Universidad de Zaragoza)
    • 1:00 PM
      Lunch Colonnade room

      Colonnade room

    • Session III Auditorium


      Convener: Carmen Palomares Espiga (CIEMAT)
      • 14
        The DUNE Photon Detection System

        The neutrino experiment DUNE, currently under construction in the US, has a broad physics program that covers oscillation physics at the GeV scale, the search for the proton decay and the observation of supernova and solar neutrinos. The DUNE far detector is based on the technology of the liquid argon time projection chamber (LArTPC), that allows for a 3D real-time position reconstruction of the events and their energy. This is possible thanks to collection of both electrons and scintillation photons produced after an interaction. The light signal in particular is key to provide the timing of the interactions. To fully exploit the light signal, DUNE will be equipped with a Photon Detection System (PDS). The main element of the PDS is a novel device called X-Arapuca, a light trap that detect scintillation photons with SiPMs. The X-Arapuca will enhance significantly the potential of DUNE at the lowest energies by improving the overall energy resolution. Thanks to an intense R&D campaign conducted in several labs and at the two ProtoDUNEs at CERN, the PDS system has been optimized and validated. We describe here the DUNE PDS, the latest results from test facilities, the plans for the future installation in DUNE and its role in the physics goals of DUNE.

        Speaker: Patricia Sanchez-Lucas (University of Granada)
      • 15
        Absolute Photon Detection Efficiency Measurement of X-ARAPUCA-VD

        DUNE is an ambitious experimental project with a wide physics program aiming to the observation of the neutrino oscillation physics like CP violation and identification of mass hierarchy, the detection of supernova and solar neutrinos and the search for the proton decay.
        The experiment is based on the liquid argon time projection chamber technology with four modules. The first of two far detectors respectively with horizontal (FD-HD) and vertical drifts (FD-VD) are under construction and are equipped with a photon detection system based on the X-ARAPUCA photodevices.
        X-ARAPUCAs are modules of light-collecting cells in which VUV photons from liquid argon scintillation light process are trapped between reflecting surfaces until they are detected by silicon photosensors.
        The measurement of the absolute photon detection efficiency (PDE) of the photodevices at liquid argon temperature represents a fundamental requirement for the characterization of the photon detection system of the DUNE experiment to be also compared with the results from Monte Carlo simulations.
        Two different versions of the X-ARAPUCA have been designed respectively for the HD and VD.
        The PDE of the X-ARAPUCA-HD has been already measured, while no measurements have been already performed for the X-ARAPUCA-VD.
        To this purpose a dedicated test has been designed at Naples cryogenic laboratory to measure the absolute PDE in liquid argon of the X-ARAPUCA-VD with dimensions of 60×60 cm^2.
        A detailed description of the facilities used will be shown, operations and methods for the measurement will be presented, results of the test will be reported. Future plans and possible upgrades will be also discussed.

        N. Canci - F. Di Capua on behalf of DUNE Collaboration

        Speaker: Francesco Di Capua (Università degli Studi di Napoli Federico II and INFN)
      • 16
        Development and characterization of customized NUV-HD-Cryo SiPMs for the DUNE experiment

        The Deep Underground Neutrino Experiment (DUNE) is an international experiment that uses Liquid Argon Time Projection Chambers (LArTPCs) for advanced neutrino science. Detectors to be used in this configuration to collect the scintillation light must be compliant with the cryogenic environment and exhibit low levels of dark noise. FBK has developed NUV-HD-Cryo SiPM technology for cryogenic applications such as the DarkSide experiment. This technology features a very low dark noise in the order of few mHz/mm2 at cryogenic temperature, thanks to a low peak value of the electric field, a low afterpulsing probability and a limited variation of the quenching resistance with temperature. Further development was carried out in the framework of the DUNE collaboration. The NUV-HD-Cryo technology was customized in order to reduce the optical CrossTalk (CT) by increasing the number of Deep Trench Isolation (DTI). In this work, the characterization of these devices is reported making a comparison between three different devices having similar gain but different number of DTIs. The optical crosstalk is reduced approximately by a factor of 3 for the device with three trenches with respect to the single trench sample, with a CT of ~10% at a PDE of 43% measured at 435nm. Thanks to this customization, these devices fulfilled the requirements to be used in the Horizontal Drift Detector of the DUNE experiment. For the mass production it is foreseen a fabrication of 140000 SiPMs to be supplied within two years. Diverse SiPM runs were produced for preliminary investigation measurements and evaluation of the mass production capability. A comparison between these runs in terms of breakdown voltage, dark current and forward resistance uniformity is reported and compared with the DUNE requirements.

        Speaker: Andrea Ficorella (Fondazione Bruno Kessler)
      • 17
        Optimization of the Photon Collector of the X-Arapuca for the DUNE FD1 and FD2

        DUNE is a challenging long-baseline accelerator experiment in construction at Fermilab and SURF (South Dakota) aiming to probe CP violation in the neutrino sector and to identify the neutrino mass hierarchy.
        The DUNE physics reaches on the observation of supernova neutrino bursts and proton decay are remarkably enhanced by the DUNE Photon Detection System (PDS) and strictly related to the Photon Detection Efficiency (PDE) of the Photon Detector unit named X-Arapuca.

        In this contribution, we will present the features and the basic performances of the FD1 X-Arapuca device, the impact of the PDE on the DUNE physics reach and the strategies we implemented to boost it. Most of them have been as well integrated in the FD2 X-Arapuca design.
        At the core of the X-Arapuca device is a large WLS tile: we’ll show and discuss the relevant features of the new photon downshifting (WLS) material, that is now the baseline product for both FD1 and FD2. Its design and production process allow to manufacture large slabs with high performances at low cost.
        It will be shown how the WLS design and features can be tailored to achieve high attenuation lengths allowing to operate large area X-Arapuca device with a photosensor coverage of O (10-2) as expected in FD2 and FD3.
        Accurate PDE measurements of the FD1 X-Arapuca cells show how the new WLS material in synergy with the above mentioned strategies enhance the PDE: the experimental results are compared to simulations. The cryo-reliability, radiopurity assessment and aging tests of the WLS material will be also presented, showing its large field of applications in Ar, Xe, Ar-Xe projects as SBND and DUNE, SOLAR, LEGEND-200, LEGEND-1000.
        Outlooks on a possible configurations FD3 XA PhCollector and its relative PDE will be also provided.

        Speaker: Dr Carla Maria Cattadori (INFN MIlano Bicocca)
      • 18
        Light-based analyses in MicroBooNE

        The MicroBooNE detector is an 85-ton active mass Liquid Argon Time Projection Chamber (LArTPC) located on-axis along the Booster Neutrino Beam (BNB). It serves as a part of the Short-Baseline Neutrino (SBN) program at Fermilab, which was primarily designed to address the MiniBooNE low energy excess. The primary signal channel in the LArTPC is ionisation, but the argon also produces large quantities of scintillation light. Prompt scintillation light in MicroBooNE is recorded with a plane of 32 PhotoMultiplier Tubes (PMTs). The scintillation light is used for accurate event timing and cosmic muon rejection, where the latter is important for on-surface detectors, such as MicroBooNE. With the 5 years of the primary physics run, we have developed several light-based analyses which will be presented in this talk. The experience we gained from MicroBooNE will benefit us for the next many years long-running Short-Baseline Neutrino (SBN) and the future DUNE programmes to properly understand the physics of the scintillation light in LArTPCs.

        Speaker: Jiaoyang/娇瑒 Li/李 (The University of Edinburgh)
      • 19
        The SBND Photon Detection System

        The Short-Baseline Near Detector (SBND) is a 112 ton Liquid Argon Time Projection Chamber (LArTPC) neutrino experiment located 110 m away from the Booster Neutrino Beam (BNB) target in Fermilab, (Illinois, USA). The main physics goals of SBND are the search for sterile neutrinos in the eV scale, the study of neutrino-argon interactions and the hunt for Beyond Standard Model physics. As a LArTPC, SBND collects the ionization electrons produced by charged particles inside the detector generating mm-level 3D pictures of the interactions, as well as scintillation light produced by argon excimers. The SBND photon detection system (PDS) is composed of 120 photomultiplier tubes (PMTs), and 196 X-ARAPUCAs, a new scalable technology that will also be used by the DUNE experiment based on trapping the light using a dichroic filter. SBND PDS is unique in collecting both VUV and visible light, re-emitted by TPB-coated foils in the cathode plane. The PDS acquires the photons providing interaction timing, triggering and background rejection, crucial for a near surface detector exposed to the cosmic rays background. In this talk, we present the current status of SBND PDS, as well as the latest characterization and installation measurements of the PDS components.

        Speaker: Rodrigo Alvarez Garrote (CIEMAT)
      • 20
        Using scintillation light to tag neutrino events in SBND

        Liquid Argon Time Projection Chambers (LArTPCs) have become one of the main detection technologies in the field of neutrino physics. In addition to the ionization charge, used to reconstruct near photographic images of neutrino interactions, LAr is also a very prolific scintillator. New experiments like the Short Baseline Near Detector (SBND) are focusing on harnessing the potential of the light signals through an innovative Photon Detection System (PDS) design. In this talk we will report the expected system performance using a comprehensive detector simulation. The novel techniques developed in SBND to improve the time resolution and to independently reconstruct the 3D location of the events using exclusively scintillation light will be described. Among the new capabilities, we will focus on the ability of SBND to accurately tag neutrino events with an expected resolution $\mathcal{O}$(ns) and ultimately retrieve the pulse structure of the Booster Neutrino Beam (BNB).

        Speaker: Francisco Javier Nicolas Arnaldos (University of Granada)
      • 21
        Light detection and Cosmic Rejection in the ICARUS LArTPC at Fermilab

        The ICARUS T600 detector is a 760-ton Liquid Argon Time Projection Chamber (LArTPC) currently operating at Fermilab as the Far Detector in the Short Baseline Neutrino (SBN) program. The SBN program is composed of three LArTPCs with a central goal of testing the sterile neutrino hypothesis. After operating for 3-years in the Gran Sasso Underground Laboratory, the ICARUS detector was shipped to CERN where it was outfitted with 360 8” Photomultiplier Tubes (PMTs) for a new optical detection system. The PMT system detects fast scintillation light from charged particles interacting in the Liquid Argon, generating the trigger signal for the full detector and allows 3D reconstruction of events. Now operating at shallow depth, the detector is exposed to a high flux of cosmic rays that can fake neutrino interactions. To mitigate this effect a Cosmic Ray Tagger (CRT) and a 3-meter-thick concrete were installed. Precise timing information from both the PMT and CRT subsystems can help to identify whether an interaction originated from inside or outside of the ICARUS cryostat. In this talk I will discuss methods for cosmogenic background reduction and timing calibration of the CRT and PMT light detection systems in ICARUS.

        Speaker: Anna Heggestuen
      • 22
        An overview of SoLAr, a novel approach to LArTPCs in the MeV range

        The SoLAr detector concept is a novel approach to enhance the liquid argon time projection chambers for neutrino measurements in the O(10) MeV energy range. The primary objective of SoLAr is to study solar neutrino properties, including the ability to identify neutrinos from the "hep-branch" of the proton-proton fusion chain occurring in the Sun.

        The SoLAr detector concept integrates both charge and light detection systems onto a single readout plane. Charge detection is accomplished using a pixelated readout system. Light is detected using VUV silicon photomultipliers, which directly measure the scintillation light produced in the liquid argon. The VUV SiPMs are arranged in an array format alongside the charge collection pads. This configuration aims to strike a balance between sufficient pixel coverage and sufficient SiPM coverage for low energy threshold and high spatial resolution for both system concurrently.

        In this talk we show results from a first prototype, SoLAr prototype v1, which was built and operated in Bern in October 2022. It collected cosmic data over a timeframe of two days. We also present plans for a second prototype, SoLAr prototype v2 to be operated in summer 2023.

        Speaker: Jonas Bürgi (Laboratory of High Energy Physics, University of Bern)
    • Poster session Colonnade room

      Colonnade room

      • 23
        Adherence of p-terphenyl (p-TP) film on the dichroic filter used on the X-ARAPUCA device

        The adhesion of the p-terphenyl film to the substrate used in the X-ARAPUCA dichroic filter is directly correlated to the long-term efficiency of this device. Six different cleaning methods were established before deposition with the intention of analyzing their contributions to the adhesion process of the film to the substrate. Three distinct techniques were used in the adhesion tests. The first consisted of an ultrasonic bath at different durations with verification of the residual mass of the substrate+film set, following an adaptation of the tape test, used in the qualitative adherence evaluation of the coating to the substrate. The second technique used was scratching by sclerometry, or “scratch test”, which consists in scratching the film with a progressive load, determining the maximum value of load supported by the film before it breaks. Finalizing the tests with the cryogenic immersion with turbulence method, since these devices will be submerged in liquid argon in the DUNE experiment. Preliminary results are in the final treatment and analysis, with a strong indication of priority given to some cleaning methods in favoring the adhesion of the film to the filters.

        Speaker: Ana Paula Mendonça (Unicamp)
      • 24
        Analysis of S1 Triplet Component in Darkside-50 Experiment

        Dark matter (DM), which constitutes five-sixths of all matter, is hypothesized to be a weakly interacting non-baryonic particle, created in the early stages of cosmic evolution. There are several experiments that aim for the detection of DM. One of the most promising candidates of DM is the Weakly Interacting Massive Particles or WIMPs. The DarkSide project aims at the direct detection of DM. It is a dual-phase liquid argon time projection chamber (LAr TPC), in which the DM is expected to interact with the argon nucleus resulting in nuclear recoils. Scintillation signal (S1) is produced as a result of the ionizing events from the DM-Ar interaction. Impurities such as O2, N2, H2O, etc. in LAr at the ppm level reduces the scintillation. These scintillation photons (128 nm) are emitted from two excimer states: the long-lived triplet state (1.5 us) and short-lived singlet state (6 ns). The N2 contamination in LAr suppresses the triplet component. Our aim is to get high-purity underground argon for the current and future DM searches. We analyse data from the DarkSide-50 experiment to obtain a lifetime of the triplet component with known purity, and then use the value as a reference for purity level in the DArT experiment, which is specifically designed for the impurity check of underground argon.

        Speaker: Clea Sunny (AstroCeNT, CAMK PAN)
      • 25
        Cryogenic setup for the characterization of wavelength-shifting materials for noble element radiation detectors

        In this work, we describe a cryogenic setup for the study of wavelength-shifting materials for optimised light collection in noble element radiation detectors, and discuss the commissioning results. This SiPM-based setup uses alpha induced scintillation in gaseous argon as the vacuum ultraviolet light source with the goal of characterising materials, such as polyethylene naphthalate (PEN) and tetraphenyl butadiene (TPB), in terms of their wavelength-shifting efficiency. Further extensions of the system are currently being studied. The foreseen upgrades are expected to allow the study of GEM-like structures potentially interesting for rare-event searches. The design of the setup will be addressed along with the first results.

        Speaker: Dr André Cortez (AstroCeNT, Nicolaus Copernicus Astronomical Center of the Polish Academy of Sciences)
      • 26
        Development & Characterization of a PEN-based Wavelength Shifting Reflector

        Liquid argon (LAr) detectors are deployed in rare event searches such as dark matter searches, neutrino oscillation experiments, and experiments searching for neutrinoless double beta decay. These detectors rely on wavelength shifting (WLS) materials to convert argon scintillation light (at 128 nm) to visible wavelengths, enabling efficient light collection with reflectors and detection by conventional photosensors. Tetraphenyl butadiene (TPB) is commonly used as a WLS material, but its scalability for large detectors is hindered by the requirement for vacuum evaporation to achieve high light yield. To address this challenge, we present the results from a comprehensive survey of WLS reflectors based on several reflector types, including 3M™ Enhanced Specular Reflector, Tetratex®, and Tyvek®, as well as various production grades and surface finishes of commercially available Teonex® polyethylene naphthalate (PEN) films, a potential scalable alternative to TPB. For characterization, three different facilities were used: a cryogenic VUV spectrometer at TUM, LArS – a kg-scale LAr setup instrumented with a VUV-sensitive PMT at UZH, and a 2-tonne LAr setup at CERN.

        Speaker: Mr Maximilian Goldbrunner (Department of Physics, Technical University of Munich, Garching, Germany)
      • 27
        Innovative media for the purification of liquid argon from nitrogen contaminations

        Liquid argon is used as active media in several neutrino and dark matter experiments (DUNE, SBND, Microboone, Icarus, Dark Side, DEAP, …). Ionization particles in liquid argon produce free charges and scintillation photons. Both signals are used to perform calorimetric measurements, particle identification, three dimensional reconstruction. Liquid argon scintillation light can be quenched and absorbed by the presence of nitrogen contaminations. In neutrino detectors electronegative contaminants, like oxygen and water, are continuously filtered, while nitrogen is not. This can lead to a reduction of scintillation signal in case of air leaks in the detector. Dark matter experiments are typically filtering nitrogen in gas phase at room temperature.
        The innovative molecular sieve is the zeolites Li-FAU. Purification tests have been performed using the Liquid Argon (LAr) Purification Cryostat (PuLArC) at IFGW/Unicamp. Previous studies regarding N2 gas capturing at T = 89K revealed a strong interaction of nitrogen with the lithium cations present in zeolite LiX. The tests performed in PuLArC have unequivocally shown that the Li-FAU adsorbent is capable of capturing N2 from recirculating LAr. The Li-FAU was able to reduce a N2 contamination of 20-50 ppm to 0.1-1.0ppm in 1-2h of circulation time. The test was repeated several times. These results invoke further investigations in larger scale LAr cryostats at Fermilab and CERN in order to support the possible use of Li-FAU molecular sieve, in replacemente of Molecular Sieve 4A, in LBNF-DUNE and other LAr experiments.

        Speaker: Dr Ana Machado (Unicamp)
      • 28
        Investigating the effect of electrode surface chemistry on high voltage pre-breakdown in noble liquids

        Liquid argon and liquid xenon detectors often encounter high voltage issues at much smaller fields than the theoretical breakdown limit. Minor electron emission events from high voltage electrodes are often sufficient to produce unacceptable deadimes, backgrounds to the physics to be investigated, and may even be harbingers of impending breakdown. These problems become more acute as the size of detectors increases, increasing the drift length, and hence the potential and stressed area for a given drift field.

        This talk will outline experiments at the Stanford liquid xenon lab exploring high voltage phenomena preceding breakdown. Unlike previous work, the emphasis here is on the surface chemistry of the electrodes, that are mechanically polished to limit effects that may be caused by mechanical asperities. With field capabilities up to 60 kV/cm over 15 cm^2 electrode surface areas, a comparison is made between the high voltage performance of polished stainless steel versus those further coated in various ways.

        Speaker: Evan Angelico (Stanford University)
      • 29
        New Results on MagLITe

        This work focuses on addressing the challenges associated with photodetection systems in liquid noble experiments. These systems typically incorporate an external wavelength shifter film, which is deposited over an optical element. However, this approach poses several issues such as cross-contamination, mechanical and chemical stresses, and photobleaching. To overcome these limitations, our research group has introduced a novel technique called MagLITe (Magnesium fluoride Light collection Improvement technique).

        MagLITe involves the application of a transparent VUV (vacuum ultraviolet) compatible material as a protective layer over the external wavelength shifter. This layer is specifically designed to be hard, durable, and compatible with the underlying structure. By implementing this technique with the right thickness, we not only mitigate the aforementioned challenges but also enhance the system's efficiency by acting as an anti-reflective VUV coating.

        In this work, we present our latest results on the topic, showcasing the advancements achieved on MagLITe.

        Speaker: Bruno Gelli (Unicamp)
      • 30
        Simulating signals in noble liquid detectors using NEST

        The Noble Element Simulation Technique (NEST) is a toolkit for simulating signals in noble liquid detectors. A variety of models have been developed to simulate ionization and scintillation signals in argon- and xenon-based detectors, trained and benchmarked against a body of data published in rare-event search experiments and dedicated calibration measurements. This presentation will discuss the models developed by NEST and their validation against the existing body of data in argon and xenon detectors.

        Speaker: Shawn Westerdale (INFN Cagliari)
      • 31
        Study of the energy response and position reconstruction with Na-22 source in DEAP-3600

        DEAP-3600 is a single-phase liquid argon (LAr) direct-detection dark matter experiment, operating 2 km underground at SNOLAB (Sudbury, Canada). The detector consists of 3.3 tons of Lar contained in a spherical acrylic vessel. At WIMP masses of 100 GeV, DEAP-3600 has a projected sensitivity of 10−46 cm2 for the spin independent elastic scattering cross section of WIMPs. External radioactive sources can be used to measure the energy calibration and to test the position reconstruction in the energy region of interest for WIMP signals. One of the most effective sources is Na-22 which is deployed in a tube located around the DEAP steel shell. Na-22 decays to an excited state of Ne-22 via a β +-decay, which de-excites by emitting a 1275 keV γ. The positron from the source decay annihilates resulting in the emission of two back-to-back 511 keV γ. The emission of the three γ particles following the Na-22 decay is nearly simultaneous, providing a very effective tagging algorithm for Na-22 decays to distinguish them from backgrounds in DEAP-3600. In this poster I will present the energy response and position reconstruction in DEAP-3600 with the Na-22 source.

        Speaker: Ludovico Luzzi (CIEMAT)
    • Session IV Auditorium


      Convener: Susana Cebrian (Universidad de Zaragoza)
      • 32
        Study of low-energy nuclear recoils in liquid argon with the ReD experiment

        Liquid Argon (LAr) Time Projection Chambers (TPC) operating in double-phase detect the nuclear recoils (NR) possibly caused by the elastic scattering of dark matter WIMP particles via light signals from both scintillation and ionization processes.
        In the scenario of a low-mass WIMP (< 2 GeV/c^{2}), the energy range for the NRs would be below 20 keV, thus making it crucial to characterize the charge yield from ionization as the lone available channel at such low energy.
        The ReD project, within the Global Argon Dark Matter Collaboration, aims to measure the charge yield of a LAr TPC down to 2 keV recoil energy.
        The measurement is being performed at the INFN Sezione of Catania. Neutrons emitted by spontaneous fission are tagged by detecting the accompanying radiation with two BaF_{2} detectors, which are used as start for time of flight (TOF) measurement. The neutron emission is collimated inside a cone with an opening of 2° and sent through the TPC. Finally, the neutron eventually scattered in the TPC is detected by 18 1-in plastic scintillators covering the angular range 12°-17°.
        The TOF of the neutron interacting in the TPC is used to reconstruct the neutron kinetic energy and to calculate the Ar recoil energy.
        The calibration of the TPC is performed by using low-energy internal sources of 83mKr and 37Ar diffused inside the TPC.
        In this contribution, we describe the experimental setup and the strategy adopted.

        Speaker: Ms Noemi Pino (University of Catania, INFN Sezione di Catania)
      • 33
        Estimation of Ar-37 activation and decay rate in DarkSide-50 experiment

        The DarkSide-50 (DS-50) experiment uses underground argon (UAr) as a target for the detection of WIMPs, one of the prime candidates for dark matter searches. During the transportation from Colorado (US) to Gran Sasso (Italy) cosmic ray interactions produce $^{37}Ar$ in the UAr. Narrow peaks corresponding to L-shell (0.27 keV) and K-shell (2.82 keV) electron capture are visible in the DS-50 70-day data after UAr is filled in the detector. This study aims to determine the decay rate of $^{37}Ar$ using DS-50 experiment data, calculate its initial activity, and independently estimate the expected activation based on measured cross-sections. The results from the DS-50 $^{37}Ar$ are important to validate the estimation of cosmic activation of $^{39}Ar$ as well as $^{37}Ar$ for future detectors. We obtained measurements of the decay time, L/K branching ratio, and initial activity, which were then compared to the estimated activation values.

        Speaker: Iftikhar Ahmad (ASTROCENT)
      • 34
        TREXDM: a time projection chamber for low mass WIMPs detection

        The TREXDM detector, a low background chamber with microbulk Micromegas readout, was commissioned in the underground laboratory of Canfranc (LSC) in 2018. Since then, data taking campaigns have been carried out with Argon and Neon mixtures, at different pressures from 1 to 4 bar. The two challenges currently faced are the reduction of the background level and the improvement of the energy threshold. Apart from studies to identify and minimize contamination populations, recently we are exploring the development of a new readout plane based on the combination of Micromegas and GEM technologies; the aim is to have a pre-amplification stage that would permit very low energy thresholds, close to the single-electron ionization energy. With respect to the background reduction, a high sensitivity alpha detector is being developed in order to allow a proper material selection for the TREXDM detector components.

        Speaker: Hector Mirallas (CAPA / University of Zaragoza)
      • 35
        CYGNO, a directional Dark Matter TPC optically readout

        CYGNO, a directional Dark Matter TPC optically readout

        We are going to discuss the latest R&D progress concerning the enhancement of the light yield in the CYGNO experiment. CYGNO is a directional detector for low mass (0.5-50 GeV) Dark Matter WIMP searches. The experiment is focused on developing a high-precision and optically readout gaseous Time Projection Chamber and, given its directional capabilities, CYGNO is also expected to be able to perform solar neutrino spectroscopy.

        In the CYGNO approach, the ionization charge is amplified by three Gas Electron Multipliers (GEMs) operating in a He:CF$_4$ mixture, a gas sensible to both spin-dependent and independent interactions. The readout system comprises scientific CMOS cameras and PMTs that read the visible light emitted during the charge amplification process. Their combined analysis allows a three-dimensional and topological reconstruction of the particle interactions in the gas.

        We will discuss the state-of-the-art results of LIME, a 50 cm prototype that was installed and commissioned in the underground laboratories of LNGS in February 2022. LIME results will help validate the design of a 0.4 m$^3$ detector which will ultimately serve as a demonstrator of the technology, performance, and scalability of the project for the experiment's phase 1 detector, a $O(30)$ m$^3$ TPC already competitive with other DM search experiments in the low WIMP mass region.

        Achieving a higher light yield would further improve CYGNO's sensitivity to lower-mass WIMPs. With this in mind, within the CYGNO R&D framework, an ITO thin glass window was introduced in our 0.5L prototype, MANGO, resulting in the introduction of an induction field where the secondary electrons are further accelerated to the point where additional scintillation is possible, and with little additional charge production. This feature was further tested using different GEM thicknesses and configurations, and a Maxwell simulation was created to study the electric fields in the regions around the GEM. Such simulation helped us in the interpretation of our results on detector energy and spatial resolutions. The cross-interpretation of experimental data acquired in these conditions and simulations will be discussed.

        David J. G. Marques* on behalf of the CYGNO collaboration

        *Gran Sasso Science Institute, 67100 L’Aquila, Italy
        Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Gran Sasso, 67100 Assergi, Italy
        Mailing Address:

        Speaker: David José Gaspar Marques (Gran Sasso Science Institute)
      • 36
        The Scintillating Bubble Chamber: Overview and Progress

        The Scintillating Bubble Chamber (SBC) Collaboration is combining the well-established bubble chamber and liquid argon scintillator technologies to build a detector specifically suited to the quasi-background-free measurement of low energy nuclear recoils. This relies on the principle that nuclear recoils induce bubble formation (nucleation) while electron recoils do not, allowing bubble-based discrimination for event energies as low as ~100eV. The scintillation signal will be used to tag and reject higher energy nucleation events and study backgrounds. This yields performance suitable for a competitive WIMP dark matter search in the 1GeV mass region and sensitivity to reactor CEvNS. Construction is nearing completion of the first chamber at Fermilab, which utilizes an active volume of 10kg of superheated liquid argon contained within two fused silica jars. The jars are surrounded by 32 silicon photomultipliers for scintillation light detection. This chamber will be used to collect calibration data, investigate performance using xenon doped liquid argon and study the effects of electric field on nucleation efficiency. A second low background chamber will be built at SNOLAB in the near future. This talk will discuss this detector’s unique functionality, construction and progress at Fermilab.

        Speaker: Austin de St Croix (Queen's University)
      • 37
        GanESS: Detecting coherent elastic neutrino-nucleus scattering with noble gases

        The recent detection of the coherent elastic neutrino-nucleus scattering (CEνNS) opens the possibility to use neutrinos to explore physics beyond standard model with small size detectors. However, the CEνNS process generates signals at the few keV level, requiring of very sensitive detecting technologies for its detection. The European Spallation Source (ESS) has been identified as an optimal source of low energy neutrinos offering an opportunity for a definitive exploration off all phenomenological applications of CEνNS.

        GanESS will use of a high-pressure noble gas time projection chamber to measure CEνNS at ESS in gaseous Xe, Ar and Kr. Such technique appears extraordinarily promising for detecting the process albeit characterization of the response to few-keV nuclear recoils will be necessary. With this goal, we are currently comissioning GaP, a small prototype capable of operating up to 50 bar. GaP will serve to fully evaluate the low energy response of the technique, with a strong focus on measuring the quenching factor for the different noble gases that will later be used at GanESS.

        In this talk I’ll give an overview of GanESS with a focus on the status of GaP and its short-term plans.

        Speaker: Dr Ander Simón Estévez (Donostia International Physics Center)
      • 38
        The RELICS Coherent Elastic Neutrino-Nucleus Scattering Experiment

        The neutrino-nucleus coherent scattering (CEνNS), known as CEνNS, has the highest cross-section among all interaction channels for MeV neutrinos, making it the most promising way of remote monitoring and detection of nuclear reactors. The biggest challenges are lowering the energy threshold to keV and sub-keV and mitigating the cosmogenic background in a sea-level detector. A liquid xenon time projection chamber (LXeTPC) is one of the most promising technologies for CEvNS search, thanks to its well-established low background and energy threshold. These advantages make LXeTPCs the leading technology in the search for WIMP dark matter. The RELICS (REactor neutrino LIquid xenon Coherent Scattering experiment) experiment aims at reactor CEνNS detection using an LXeTPC. In this talk, I will introduce the RELICS experiment with a focus on its status and discovery potential for CEvNS signals from reactor neutrinos.

        Speaker: Fei Gao (Tsinghua University)
    • 10:55 AM
      Coffee & tea break Colonnade room

      Colonnade room

    • Session V Auditorium


      Convener: Francesc Monrabal (Donostia International Physics Center)
      • 39
        Search for neutrinoless double beta decay with the NEXT experiment

        The NEXT (Neutrino Experiment with a Xenon TPC) collaboration seeks to discover the neutrinoless double beta decay (ββ0ν) of Xe-136 using a high-pressure gas time projection chamber with electroluminesence gain and optical read-out. A first medium-scale prototype with 5-kg of xenon, NEXT-White, operated at the Laboratorio Subterraneo de Canfranc (LSC) from 2016 to 2021. This prototype has proven the outstanding performance of the NEXT technology in terms of energy resolution (<1% FWHM at 2.6 MeV) and event topology reconstruction to identify signal and background events. Currently, the collaboration is constructing the NEXT-100 detector holding 100 kg of Xe-136 at 15 bar which is expected to start data taking at the end of 2023. In this talk, I will review the most recent results of the NEXT-White detector, I will describe the NEXT-100 detector and the plans to further extend the technology for a future tonne-scale NEXT detector.

        Speaker: Neus López March (IFIC (Universitat de València - CSIC))
      • 40
        Towards a fiber barrel detector for next-generation high-pressure gaseous xenon TPCs

        The NEXT (Neutrino Experiment with a Xenon TPC) project is an international collaboration aimed at finding evidence of neutrinoless double beta decay using gaseous xenon. The current phase of the project involves the construction and operation of NEXT-100, which is designed to hold 100 kg of xenon at 15 bar and is expected to start commissioning in the fourth quarter of 2023. NEXT-HD will be a tonne scale experiment following NEXT-100 and will incorporate a symmetric design, with one cathode and two anodes. For this detector, the collaboration is considering implementing a barrel of wavelength-shifting fibers read out by silicon photomultipliers to measure the energy. In this talk, we will discuss the characteristics of this approach and provide an update on the related R&D efforts.

        Speaker: Stefano Roberto Soleti (
      • 41
        Searching for neutrinoless double beta decay using the nEXO detector
        Speaker: Mr Evan Angelico
      • 42
        Status and Prospects of the XEMIS2 experiment

        I will provide an overview of the most famous experimental developments proposed so far with prototypes comprising liquid xenon in order to supplant the solid cameras used today in functional medical PET gamma-rays imaging. A parenthesis also addresses the operating principle of Compton telescopes will be provided in order to motivate their future use in the context of XEMIS (Xenon Medical Imaging System) experiments.
        XEMIS2 is a project that uses liquid xenon (LXe) to provide a significant improvement in Small Animal Compton Medical Imaging. Currently being installed at the Nantes hospital (Nantes CHU), the camera is like a small physics experiment containing 200 kg of liquid xenon and its associated infrastructure. The active zone consists of a time projection chamber (single phase liquid xenon TPC) allowing precise measurement of the charge and the light produced by the interaction of high energy gamma-rays. The technology deployed for reading ionization signals is adapted from the principles used by micropattern gaseous detectors, the anodes contain 20000 pixels of 3x3 mm2 sides and the experimental measurement chain is entirely specific. The noise level measured on each of the pixels at room temperature is close to 100 electrons, and we hope thanks to these performances to be able to locate electronic recoils in liquid xenon with a spatial resolution of 100 microns in each of the 3 dimensions.
        Thus, thanks to these exceptional technological performances, we plan to produce very good images with very little radioactivity in the field of view by using the principle of Compton imaging, in particular that implemented for the observation of labeled drugs with 44-Scandium emitting 3 photons in quasi spatial and temporal coincidences.
        The first images are thus planned with 20 kBq of activity present in the small animal and with an exposure time of 20 mns, the camera should come into operation from the beginning of the year 2024. The complete and specific system of acquisition that has been developed for recorded information will also be presented.
        Finally, XEMIS2 is a first demonstrator of the unique capability of experiments containing liquid xenon for Compton medical imaging. The prospects for evolution in order to gradually reach the human scale will also be presented.

        Speaker: Dominique Thers (SUBATECH)
      • 43
        The PETALO project

        PETALO (Positron Emission TOF Apparatus with Liquid xenOn) is a project that uses liquid xenon (LXe) as a scintillation medium, silicon photomultipliers as a readout and fast electronics to provide a significant improvement in PET-TOF technology. Liquid xenon allows one to build a continuous detector with a high stopping power for 511-keV gammas. In addition, SiPMs enable a fast and accurate measurement of the time and energy with a small dark count rate at the low temperatures required from LXe. PETit, the first PETALO prototype built at IFIC (Valencia), consists of an aluminum box with one volume of LXe and two planes of VUV SiPMs, which register the scintillation light emitted in xenon by the gammas coming from a Na22 radioactive source placed in the middle. The LXe volume is divided in small, highly reflective cells to enhance light collection.
        In this talk I will describe the PETALO concept and present the first measurements performed with PETit.

        Speaker: Nerea Salor Iguiñiz
      • 44
        Advancements in Total-Body PET Imaging: Xenon-Doped Liquid Argon Scintillator and Silicon Photomultiplier Detection

        The 3DΠ project, developed in collaboration with DarkSide, introduces a novel Total-Body (TB), Time Of Flight (TOF), Positron Emission Tomography (PET) scanner for medical imaging. This project builds upon the advancements made by the DarkSide collaboration in Liquid Argon(LAr) detector technology, low-radioactivity argon procurement, and cryogenic photosensor development.

        The 3DΠ scanner incorporates a cutting-edge scintillator system that utilizes Xenon-doped Liquid Argon (LAr+Xe) and Silicon Photomultiplier (SiPM) panels. By adding Xenon doping, the long-lifetime component of the scintillation light is effectively reduced, allowing for higher data rates. This approach enables faster processes compared to other methods involving a wavelength shifter. Additionally, cooling the SiPMs to match the temperature of LAr significantly reduces the dark count rate within the SiPM. In our talk, we will primarily focus on the concept design and advantages of the 3DΠ scanner, including the standardized NEMA performance results.

        Preliminary findings from NEMA tests indicate that the performance of our scanner's system is comparable, if not superior to, other commercial scanners. By emphasizing the innovative design and key advantages of the 3DΠ scanner, we aim to convey the potential impact of this technology in the field of medical imaging.

        Speaker: Dr Azam Zabihi (Nicolaus Copernicus Astronomical Center of the Polish Academy of Sciences, ASTROCENT, Warsaw, Poland)
    • 1:05 PM
      Lunch Colonnade room

      Colonnade room

    • Session VI Auditorium


      Convener: Joaquim Palacio Navarro (Laboratorio Subterráneo de Canfranc)
      • 45
        A Compact Real Time Segmented Double-Scatter Neutron/Gamma Imager

        Segmented double-scatter Compton camera systems have been widely used for imaging gamma sources. There are examples of the same technique applied for neutron source imaging, however, such devices tend to be bulky and require considerable supporting infra-structure. We will present a compact design that utilizes a segmented scintillator stack, SiPMs, NeuPix ASICs, and an FPGA-based readout system. This device is battery operated and will be hand-held portable because none of the components require high voltage to operate. Design features of the imager and preliminary results will be presented. Programmable flexibility inherent the NeuPix ASIC will be described, and performance data will also be presented. The relevance of this effort to LIDINE lies in applications requiring neutron scattering based calibrations of prototype dark matter detectors, imaging of background neutrons/gammas, and design of new experiments based on this technology.

        Speaker: Mani Tripathi (UC Davis)
      • 46
        Infrared Cathodoluminescence of Xe2 Excimers in Dense Xe-Noble Gas Mixtures

        The injection of energetic electrons in dense gases and liquids is a technique widely used to accomplish several goals. In particular, how hot electrons thermalize in a dense gas or in a liquid is a subject that has attracted much attention. Hot electrons can lose their energy along multiple energy degradation paths. Dense rare gases efficiently convert the electron kinetic energy by exciting atomic levels. Collisions of excited noble gas atoms with ground state ones may lead to the formation of excimers in high-lying molecular levels. The excimer deexcitation to the dissociative molecular ground state releases a relevant fraction of the excitation energy to a relatively narrow band in the vacuum ultraviolet (VUV) range. In a previous experiment in an electron beam excited, dense Xe gas we have been able to detect an infrared (IR) band originating from a bound-free electronic transition between higher lying molecular states. The location of the relatively broad IR excimer band has been found to depend on the host gas density. Namely, the band maximum linearly shifts to longer wavelength as the density is increased. We explained the experimental observation by accounting fort two effects, one classical and one quantum mechanical. The excimer is considered as consisting of an ionic core plus an electron in a large, Rydberg-like orbit. Several host gas atoms atoms are encompassed within the orbit so that they act as a dielectric screen that reduces the Coulombic interaction between the optically active electron and the ionic core thereby changing its energy. Furthermore, the quantum wavelength of the delocalized Rydberg electron is so large as to make it interact with many atoms at once. As a result of the combined effect of the atomic polarizability and the electron atom-scattering length in pure Xe gas the energy of the electronic transition in the excimer is reduced as density is increased. We confirmed this model by also measuring the Xe excimer in a 10%Xe-90%Ar mixture. The model holds true if the polarizability and scattering length of Xe are replaced by those of Ar because in the mixture the Xe2 excimer is mainly surrounded by Ar atoms. In order to further confirm our model we are now carrying out spectroscopic measurements of the cathodoluminescence of the Xe2 excimer in several mixtures with different noble gases. In particular, we are studying mixtures with He, whose atomic polarizability is roughly one order of magnitude smaller than that of Xe and its electron-atom scattering length has opposite sign with respect to Xe. Thus, we should be able, by exploiting the law of ideal mixtures, to tailor the density dependent shift of the excimer spectrum maximum by simply adjusting the Xe-He concentration. Now, we report the first results obtained with several Xe-noble gas mixtures.

        Speaker: Prof. Armando Francesco Borghesani (Dipartimento di Fisica & Astronomia, Università degli Studi di Padova)
      • 47
        The Capabilities of the Liquid Xenon Proportional Scintillator Counter for Low-energy Event Detection

        The Liquid Xenon Proportional Scintillation Counter (LXePSC) is a single-phase liquid xenon detector capable of producing electroluminescence directly in the liquid phase. In doing so, we are able to disregard the extraction efficiency, as seen in dual phase LXeTPCs, and simplify the detector design and operation by not needing to maintain a liquid-gas interface. In this talk, we will present our recently published results, which include the detection of low-energy electronic recoils down to ~1 keV, as well as evidence of single-electron signals from photo-induced electron emission of cathode surfaces. Furthermore, we will present preliminary results of our recent run, which includes a potential for nuclear and electronic recoil discrimination using the LXePSC, and an improved energy calibration using activated xenon lines.

        Speaker: Jianyang Qi (UCSD)
      • 48
        First observation of liquid xenon electroluminescence with Micro-Strip plates

        Some recent noble-liquid electron-multiplier concepts have been recently proposed as potential sensing elements of single-phase detectors. They aim at overcoming current liquid-to-gas interface instabilities in large-area dual-phase TPCs.

        We report the first observation of electroluminescence (EL) of liquid xenon with Micro-Strip plates (MSPs), similar to those used in gas Micro-Strip Plate Chambers (MSPCs). Electrons extracted from alpha-particle tracks induce EL directly in the liquid in the strong, non-uniform electric field produced in the vicinity of narrow (few μm) anode strips deposited on a glass substrate. The high intensity of the electric field is enough to also induce a small charge avalanche. Both primary scintillation (due to alpha particles) and EL (due to the extracted electrons) were measured by a photomultiplier also immersed in liquid xenon. The electroluminescence light yield and the charge multiplication factor were measured.

        The preliminary results of the performance of two small-size MSP prototypes of different strip geometries will be presented. Their potential impact on future large-volume noble-liquid detectors and further R&D plans will be discussed.

        Speaker: Gonzalo Martínez Lema (Weizmann Institute of Science, Ben Gurion University)
      • 49
        First time-resolved measurement of infrared scintillation light in gaseous xenon

        Xenon in gaseous and liquid form is a widely used detector target material for rare-event searches, including the direct detection of dark matter. Its scintillation properties in the ultraviolet (UV) spectrum are well-known and extensively utilized. However, the use of infrared (IR) scintillation light in xenon-based detectors remains largely unexplored. This contribution presents the first measurements of the time profile of the IR scintillation response in gaseous xenon.
        Our dedicated setup incorporates an alpha particle source as well as one IR- and two UV-sensitive photomultiplier tubes. This enables precise nanosecond-resolution timing measurements of IR signals along with simultaneous measurement of the UV component. We observe that the IR time response can be described by a fast ($\mathcal{O}(\mathrm{ns})$) and a slow (($\mathcal{O}(µs)$) decay component. Remarkably, the size of the slow component decreases with increasing impurity levels in the gas. With this measurement, we can estimate the IR light yield and find that it is in the same order of magnitude as the UV yield.
        These findings advance our understanding of the IR scintillation response in gaseous xenon and its potential implications for the development of future xenon-based detectors.

        Speaker: Mr Robert Hammann (Max-Planck-Institut für Kernphysik (MPIK))
      • 50
        Scintillation of Ar-CF4 mixtures

        Both the spectrum and primary scintillation yields of Argon-CF4 mixtures have been measured with an x-ray tube and an alpha source, respectively, in a broad range of concentrations and pressures. In the studied range of 220-800 nm, these mixtures scintillate mainly in four bands centered on 260, 290, 370 and 625 nm. Scintillation is clearly noticeable for as little as 0.1% of CF4 in the mixture, part of it being attributable to transfer reactions between the excited argon states and the CF4 molecules.

        The large scintillation yields and short time constants of the emission, together with spectral characteristics that are suitable for SiPM detection, could in principle allow time tagging in large-volume Ar-based gaseous TPCs down to an energy threshold around 1 MeV, with ns-resolution.

        Speaker: Pablo Amedo Martinez (Galician Institute of High Energy Physics (IGFAE))
      • 51
        Primary scintillation yield in gaseous Xe for electrons and alpha-particles

        Xenon scintillation has been widely used in recent particle physics experiments. However, information on the primary scintillation yield in the absence of recombination is still scarce and dispersed. The mean energy required to produce a Vacuum Ultraviolet (VUV) scintillation photon (Wsc) in gaseous Xe has been measured in the 30–120 eV range. Lower Wsc-values are often reported for alpha particles compared to electrons produced by gamma- and x-rays, being this difference not understood.

        We carried out a systematic study of the absolute primary scintillation yield in Xe at 1.2 bar, using a Gas Proportional Scintillation Counter. The simulation model of the detector's geometric efficiency was validated using the absolute secondary scintillation yield. The Wsc parameter was measured for gamma- and x-rays in the 5.9–60 keV energy range, and for alpha-particles in the 1.5–2.5 MeV energy range.

        Neglecting the 3rd continuum emission, a mean Wsc-value of 38.7 ± 0.6 (sta.) +7.7 −7.2 (sys.) eV was obtained, and no significant dependency neither on radiation type nor on energy has been observed. Results considering the 2nd and 3rd continua separately are also presented. Our experimental Wsc-values agree with both state-of-art simulations and literature data obtained for alpha-particles. The discrepancy between our results and the experimental values found in literature for x/gamma-rays is attributed to undressed large systematic errors.

        Speaker: Dr Carlos Henriques (LIBPhys-Coimbra, Department of Physics, University of Coimbra)
    • 3:55 PM
      Coffee & tea break Colonnade room

      Colonnade room

    • Discussion session Auditorium


      • 52
        R&D in the frontier Fausto Elhuyar hall

        Fausto Elhuyar hall

        Speakers: Dr Diego González Díaz, Francesc Monrabal (Donostia International Physics Center), Laura Perez-Molina (CIEMAT)
      • 53
        Scale-up challenges Auditorium


        Speakers: Auke-Pieter Colijn (Nikhef / University of Amsterdam), Ludovico Luzzi (CIEMAT), Shawn Westerdale (INFN Cagliari)
    • 8:00 PM
      Dinner Restaurante Sal Gorda

      Restaurante Sal Gorda

      C/ Beatriz de Bobadilla, 9, 28040 Madrid
    • Session VII Auditorium


      Convener: Gloria Luzón Marco (CAPA, Universidad de Zaragoza (ES))
      • 54
        Current and future challenges when operating the ATLAS Liquid Argon Calorimeter

        The Liquid Argon Calorimeters are employed by ATLAS for precision electromagnetic calorimetry and for hadronic and forward calorimetry in the forward region. They also provide inputs to the first level of the ATLAS trigger system.

        Since 2022, the LHC has restarted with the perspective of an increase of the instantaneous luminosity and pile-up of up to 80 interactions per bunch crossing. The HL-LHC upgrade planned to be fully functional in 2029 should push the pile-up even further.

        To cope with these always harsher conditions the readout of the LAr Calorimeters had to be updated. In the LHC shutdown before 2022 a new trigger readout path has been installed that improved significantly the triggering performances on electromagnetic objects. This was achieved by increasing the granularity of the readout units available per collision by a factor of up to 10. New digitizer and processing boards were added on and off detector taking advantage of the recent electronics. This allowed a very compact and very efficient system treating up to 31Tbps.

        With the expected HL-LHC pile-up of 200 proton collision every 25ns and the induced increase of radiation dose, the current readout will have to be fully exchanged. The most recent and powerful technology allowing now to readout the full detector granularity at 40MHz will push the amount of data that could be processed online even further to always improve the efficiency of the event selection.

        This contribution will highlight the present and futures the challenges in the operation of such a detector.

        Speaker: Tom Kresse (IKTP (TU Dresden))
      • 55
        DarkSide-20k Veto: construction and characterization

        Darkside-20k is a global direct dark matter search experiment situated underground at LNGS (Italy), designed to reach a total exposure of 200 tonne-years nearly free from instrumental backgrounds. The core of the detector is a dual-phase Time Projection Chamber (TPC) filled with 50 tonnes of low-radioactivity liquid argon.
        The entire TPC wall is surrounded by a gadolinium-loaded polymethylmethacrylate (Gd-PMMA), which acts as a neutron veto, immersed in a second low-radioactivity liquid argon bath enclosed in a stainless steel vessel. The neutron veto is equipped with large-area Silicon Photomultiplier (SiPM) array detectors, placed on the TPC wall. SiPMs are arranged in a compact design meant to minimize the material used for Printed Circuit Boards, cables and connectors: so-called Veto PhotoDetection Units (vPDUs).

        A vPDU comprises 16 Tiles, each containing 24 SIPMs, together with front-end electronics, and a motherboard, which distributes voltage and control signals, sums tiles channels, and drives the electrical signal transmission. The neutron veto will be equipped with 120 vPDUs.
        The talk will focus on the production of the first vPDUs, describing the assembly chain in the UK institutes, in order to underline the rigorous QA/QC procedures, up to the final characterization of the first completed prototypes.
        Tests have been extensively performed in liquid nitrogen baths either for the single Tiles (at RHUL) and for the assembled vPDUs, with the purpose to assign a “quality passport” for each component.

        Speaker: Paolo Franchini (Lancaster University - Royal Holloway University of London)
      • 56
        Digital SiPM array with high fill factor and data driven readout for photon detection in liquid noble gas experiments

        We have developed a large area $(8 \times 9\,\mathrm{mm}^2)$ digital SiPM array with a high fill factor $(77\%)$ for light detection in rare event search experiments with liquid noble gases. Digital SiPMs combine SPADs and CMOS logic on the same silicon substrate so that the SPAD hits can be processed on-chip and the chip output signals are purely digital. This reduces power consumption and system complexity. Our chip consists of a large pixel matrix of $16\times 60$ so-called macropixels of $240 \times 291\,\mu\mathrm{m}^2$ and a narrow band of synthesized, data-driven readout logic located at its bottom. Each macropixel contains 9 SPADs and some CMOS logic which allows for disabling each SPAD in case its noise rate is too high, and a logical OR combining all SPAD signals to create a common macropixel hit signal. The hit signal is stored in a flipflop, so that multiple coincident hits in the matrix are possible. A readout logic in the periphery searches the matrix for hits and writes their X- and Y-address as well as an associated column-wise time information $(\Delta T = 10\,\mathrm{ns})$ into a FIFO. The FIFO data is injected into a serial data stream such that up to 64 chips can be read out through one digital signal in a serial chain. In total, a chip chain requires only seven signals: 3 analogue signals for power, ground and SPAD bias and 4 digital signals for clock, command and serial input and output. The SPADs are of excellent quality, offering a dark count rate of $0.02\,\mathrm{Hz/mm}^2$ at liquid xenon temperature $(T = 165\,\mathrm{K})$. The quantum efficiency at blue light is about $40\%$ and the manufacturer is currently optimizing it for deep VUV light. The number of SPADs with increased noise at $T = 165\,\mathrm{K}$ is about $10\%$, so that turning those off results in a moderate loss in active area.

        Speaker: Michael Keller (University of Heidelberg)
      • 57
        A novel amorphous selenium based photosensor for liquid noble detectors

        Detection of the vacuum ultraviolet (VUV) scintillation light produced by liquid noble elements will be of central importance to fully exploit the potential of future time projection chambers (TPCs) using these media. A novel technology recently proposed to detect VUV light is based on a windowless amorphous selenium photosensor. This device would open the door to the possibility of making an integrated charge plus light sensor, which would be simultaneously sensitive to the two signals of a liquid noble gas TPC. This would allow for a larger effective area, provide an increased sensitivity to the low energy physics (few MeV) and greater fidelity in energy reconstruction. We present here the concept of the amorphous selenium photosensor and the experimental results that show that the proof-of-principle is robust under cryogenic conditions. We report as well about the R&D ongoing and the latest light simulation tools developed to benchmark the performance of the device.

        Speaker: Patricia Sanchez-Lucas (University of Granada)
      • 58
        Measurement of the Photon Detection Efficiency of Hamamatsu VUV4 SiPMs at Cryogenic Temperature

        The presentation will focus on the challenges faced in detecting scintillation photons in liquid argon TPCs related to their short wavelength and the cryogenic temperatures (~87K) at which the sensors need to be effective. To enhance the photon detection efficiency (PDE) of the photon detectors it is common the use of wavelength shifters. This leads to the introduction of the studied sensors, the Hamamatsu VUV4 S13370 - 6075CN SiPMs, that are VUV-sensitive sensors that have the potential to directly detect VUV light without the use of wavelength shifters, which among other advantages have an improved photon detection efficiency. The manufacturer provides a complete characterization of these sensors at room temperature (RT); however, previous studies showed a decrease off the efficiency with temperature. The CIEMAT neutrino group have developed experimental setups to measure this decrease in PDE of VUV4 SiPMs at 87K for different wavelengths in the range (270nm to 570nm). The results of these measurements, demonstrating the PDE decrease, will be discussed and compared with the manufacturer's characterization data at RT. A dedicated measurement at 128nm will be also shown.

        Speaker: Laura Perez-Molina (CIEMAT)
      • 59
        Front-end Application Specific Circuits in 65 nm CMOS for Light and Charge Readout

        In this talk, we present the progress on development of CMOS-based front-end application-specific integrated circuits (ASICs) for charge and light readout undertaken at Brookhaven National Laboratory. This design evolves from the LArASIC chip manufactured in 0.18 µm, that has been selected for charge readout in the liquid argon time protection chamber (LArTPC) in the phase I of DUNE. LArASIC is the first component in a 3-ASIC readout chain, realizing amplification with transformation of charge to a pulse-shaped voltage waveform. DUNE explores neutrino oscillations, interactions and transformations and is carried out at liquid argon temperatures (i.e., 87 K). The efforts aim at translation and introduction of the required modifications of the legacy design to a scaled CMOS technology, i.e., 65 nm, that can be used in future experiments. The front-end ASIC is designed to have two amplification stages with a programmable gain followed by a $5^{th}$ order semi-gaussian filter for pulse shaping, suitable to operate at cryogenic temperature, whereas it also suits testing at room temperature. We will discuss the design choices we make for the 65 nm chip that enable readout with variable pulse peaking times in the long, i.e., 0.5-2 µs, and short 10 ns-100 ns range within a power budget of 10 mW with an ENC less than 500 electrons RMS with the input capacitance on the order of a couple hundred pico farads. Along with exploiting the benefits of transistor scaling and improved transistor $f_T$ to achieve the above-mentioned goals, we make use of techniques such as self-cascoding and $I^2C$ based programmability to create a more robust and flexible design. The targets for this development are such as light/charge readout in Far Detector (FD) 2/3/4 in phase II of DUNE, LXe calorimeter in PIONEER, etc.

        Speaker: Prashansa Mukim
    • 10:45 AM
      Coffee & tea break Colonnade room

      Colonnade room

    • Session VIII Auditorium


      Convener: Paola Ferrario
      • 60
        Instruments and methods for coating of wavelength-shifting materials used for noble liquid technology

        The use of wavelength-shifting coatings are of primary interest in the area of liquified noble gases detectors, namely, argon and xenon used as active medium in the neutrino
        physics and dark matter experiments.
        In fact, charged particles crossing the noble liquid volume produce excitation and ionization followed by recombination and both the processes lead to the emission of VUV light.
        Noble liquid scintillation light emitted in the VUV range needs to be converted to be detected by conventional photosensors.
        Wavelength-shifting (WLS) materials, such as TetraPhenyl-Butadiene and P-Terphenyl, are especially used for this conversion in the visible range. In particular, the wavelength-shifters are very important in the case of large area detectors since only a fraction of the surface can be instrumented.
        To this purpose dedicated set-ups have been built and specific techniques have been adopted to produce and characterize very uniform wavelength-shifting coatings on highly reflecting material substrates and/or optical filters.
        Some of the facilities used to this task will be described, operations for production of the coatings will be reported and methods for the characteriztion of the samples will be presented. Improvement on the techniques will be also discussed.

        Speaker: Nicola Canci (INFN)
      • 61
        How can far UV coatings help detect dark matter?

        Dual-phase (gas-liquid) argon (Ar) and xenon (Xe) time projection chambers (TPC) are promising dark-matter (DM) detectors; hence various international collaborations plan to construct big TPCs based on them. Interactions in these detectors induce scintillation in the far ultraviolet (FUV) at ~128 mn (Ar) or ~172 nm (Xe).
        Unfortunately, coatings for the FUV present an intrinsic challenge compared to other ranges like the visible due to the strong absorption of materials and the limited knowledge of optical constants in this range. Thus, TPC experiments would significantly improve from the development of high-performance FUV coatings to properly handle this radiation.
        In this context, Grupo de Óptica de Láminas Delgadas (GOLD) is an expert in the development of FUV coatings. Such coatings are designed as a multilayer that alternates layers of (at least) two materials, with refractive indices and thicknesses optimized for a specific goal, such as high-reflectance narrow- or broad-band mirrors and anti-reflection coatings. FUV coatings for liquefied noble elements present an additional challenge in that they need to operate at cryogenic temperatures.
        Our communication will display the main FUV coatings that are available and other coatings that could be produced with applications for rare event searches.

        Speaker: Juan Ignacio Larruquert (Instituto de Óptica - Consejo Superior de Investigaciones Científicas)
      • 62
        Fluorescence properties of Clevios coatings for noble liquid TPC experiments

        Noble liquid scintillators like argon (LAr) and xenon (LXe) are used as the main detection medium for many particle and rare-event search detectors in part due to their high scintillation yield, background rejection capabilities and scalability to large volumes. Many detectors combine measurements of the scintillation light from the noble liquids with a time projection chamber (TPC) which detects ionization electrons produced in the noble liquid from particle interactions. An electric field drifts these electrons towards a detection plane and the timing of the signal can provide position reconstruction information for these events. Clevios is an optically conductive organic polymer that can be coated onto a transparent scintillator containment vessel to act as the electrodes in a TPC. This configuration allows scintillation light to pass through the electrode coating to be detected by photodetectors on the other side of the vessel.

        For Clevios and other materials between the scintillator and the photodetectors, it is important to understand if any emit undesirable fluorescent light that can contribute to the detector background signal. Fluorescence properties can often change with temperature, so it is also useful to study the material at the operating temperature of the detector.

        The optical cryostat lab at Queen’s is well suited to study the photoluminescent properties of scintillators, substrates and coating at temperatures of 300 K to 4 K. We present the results of our studies into the fluorescence of Clevios including its change in detected light yield with temperature, spectral features and absorbance.

        Speaker: Emma Ellingwood (Queen's University)
      • 63
        Development of wavelength-shifting PEN foils for next generation experiments

        Polyethylene naphthalate (PEN) foils have been demonstrated as a wavelength shifter suitable for operation in liquid argon. At the same time wavelength shifting efficiency of technical grades of PEN, commercially available on the market, is lower than that of tetraphenyl butadiene. This talk will report on an R&D program focused on exploring the intrinsic limitations of PEN and optimizing it for highest wavelength shifting efficiency. An important component of this effort is launching a new cryogenic facility for WLS characterization, which utilizes alpha induced gaseous argon scintillation, and will soon be upgraded with a pulsed nanosecond VUV light source.

        Speaker: Marcin Kuźniak (AstroCeNT, CAMK PAN)
      • 64
        Polyethylene Naphthalate (PEN) in LEGEND-1000

        The LEGEND experiment aims to detect the neutrinoless double beta decay of $^{76}$Ge, which would prove the Majorana nature of neutrinos, with a sensitivity for the half-life of $10^{28}$ years. To this end, one tonne of high-purity germanium (HPGe) detectors will be deployed in a segmented liquid argon (LAr) medium, which is used as coolant and instrumented as a detector for the active reduction of backgrounds. To further increase the background suppression efficiency, the scintillating and wavelength shifting polymer polyethylene naphthalate (PEN) will be used throughout the experiment. In this talk, we present the utilization of PEN for replacing optically inactive structural components, HPGe detector encapsulation and large-scale thin films. In order to meet the background limits and light yield requirements of the experiment, custom synthesis and moulding of PEN on semi-industrial scale is pursued. We report on the first results of a successful kilogram-scale production of PEN with full control over the production cycle. In addition, the photoluminescence yield and spectrum of the custom-made PEN after irradiation with VUV photons (128 nm) for temperatures between 300 K and 87 K are shown. Lastly, we give an outlook on further steps in the production and characterization of custom-made PEN.

        Speaker: Mr Andreas Leonhardt (Department of Physics, Technical University of Munich, Garching, Germany)
    • 12:30 PM
      Lunch Colonnade room

      Colonnade room

    • Session IX Auditorium


      Convener: Vicente Pesudo Fortes (CIEMAT)
      • 65
        A liquid-phase circulation-mode argon purification system

        The successful operation of noble fluid particle detectors relies on adhering to stringent purity constraints. To take full advantage of the scintillation performance of liquid argon, sub-ppm levels of impurity concentrations must be achieved. Commercial providers do not reliably meet these requirements, thus creating the need for on-site purification. We designed and constructed a liquid-phase purification system to remove contaminants commonly present in liquid argon. A molecular sieve extracts water, whereas activated copper removes oxygen. A limited amount of nitrogen is retained in the system as well, although it is not optimized for that. The purifier is used in-line to fill the shallow-underground SCARF cryostat with 1 ton of high-purity liquid argon. To demonstrate the purification performance, LLAMA measures in-situ the liquid argon scintillation and optical properties. In addition to in-line purification while filling, the system purifies liquid argon also in circulation mode using a cryogenic submersion pump. Here, we present the design of SCARF's liquid argon purification system as well as its performance during initial filling and recirculation.

        Speaker: Christoph Vogl (Technical University of Munich, TUM School of Natural Sciences, Department of Physics, James-Franck-Str. 1, 85748 Garching, Germany)
      • 66
        Photon Detection Efficiency for X-ARAPUCA sensitive for visible light

        The X-ARAPUCA is an innovative photon detection device based on the use of a short pass dichroic filters with an appropriate cut-off wavelength, two wavelength shifters and an array of SiPM. This device was idealized and developed to detect liquid argon scintillation photons in large liquid argon time projection chambers (LArTPC). The scintillation light is produced in the vacuum ultraviolet VUV range, (127nm). Thanks to its high efficiency, especially for low energy events, the X-ARAPUCA was chosen as the baseline device for the photon detection system (PDS) of the DUNE (Deep Underground neutrino Experiment) far detectors and for integrating the PDS of SBND (Short Baseline Near Detector) experiment. In SBND, in addition to the standard X-ARAPUCAs for detecting VUV light, there is also a set of X-ARAPUCAs specifically developed to detect visible light, re-emitted by a thin film of TetraPhenyl Butadiene (TPB) deposited on the cathode of the LArTPC.
        The measurement of the detection efficiency of VIS X-ARAPUCA, performed for the first time at UNICAMP, will be presented.

        Speaker: Gabriel Botogoske (Unicamp)
      • 67
        Ar37 source production for low-energy calibration

        The search for light dark matter (<10 $GeV/c^2$) has become increasingly important, since no conclusive evidence has been found in the higher dark matter (DM) mass region. In order to explore this light mass range, it is necessary to accurately model the response of the noble liquid time projection chamber (TPC) detectors, used in many experiments aimed at the direct measurement of DM, to low energy (<1 keV) nuclear recoils (NRs). In this respect, $^{37}$Ar provides an ideal calibration source in the low-energy region due to its two low-energy peaks at 0.27 and 2.82 keV following electron capture with a 35-day half-life. We propose a method to produce $^{37}$Ar without chemical or heating treatments by using the $^{40}$Ca(n,α)$^{37}$Ar reaction. This can be achieved by irradiating nano-CaO powder with a neutron source (e.g. AmBe) and allowing the produced $^{37}$Ar to diffuse into the argon used inside a double-phase TPC. By measuring the NR yields relative to those two low-energy points in the Recoil Directionality (ReD) experiment, other detectors can be cross-calibrated with the same source deployed. In this talk, the $^{37}$Ar source production, its deployment, and preliminary results will be presented.

        Speaker: Paules Zakhary (AstroCeNT, CAMK, PAN)
      • 68
        Charge and Light Yields of 127Xe Inner Shell Electron Captures

        Dark matter searches using dual-phase xenon time projection chambers (LXe-TPC), such as LUX-ZEPLIN (LZ), use the ratio of charge signal to light signal to discriminate between electron recoils and nuclear recoils. The charge and light yields of electron recoils are often calibrated with 𝛽-decays, such as 3H and 212Pb. These 𝛽-decays produce recoils primarily from outer shell electrons, while other processes may result in vacancies in inner electron shells. In all cases, contributions from the subsequent atomic de-excitation must be calibrated. Previously, the XELDA LXe-TPC has measured the charge and light yields of these atomic de-excitations, using 127Xe electron capture (EC) decays. This result showed that the yields from atomic de-excitations following inner-shell electron captures differed from those of 𝛽-decays, appearing somewhat more ‘nuclear-recoil like’. Here, I calibrate this effect using in-situ data from LZ, demonstrating potential for in-situ calibrations from future large LXe-TPCs. With these inner shell atomic de-excitation calibrations, we can better-inform our modelling of not only 127Xe EC decays, but also neutrino - inner shell electron scatters and 124Xe ECEC decays, reducing risk of false discovery claims.

        Speaker: Jacob Bargemann (University of California, Santa Barbara)
      • 69
        Deep Learning for position reconstruction

        Deep Learning (DL) is nowadays ubiquitous. In Particle Physics there is a wide portfolio of successful applications. Position reconstruction is one of the areas where DL has been applied in the past. In this talk we present preliminary research on position reconstruction DL-based in large liquid argon detectors, and a roadmap of future developments. Additionally, efforts to apply Explainable Artificial Intelligence (XAI) are also shown. XAI allows understanding which are the informative variables. Thus, it permits an in-depth comprehension of the decision-making process at the same time it avoids biased learning.

        Speaker: Miguel Cárdenas-Montes (CIEMAT)
      • 70
        Cherenkov Light Identification at CCM

        The Coherent CAPTAIN-Mills (CCM) experiment is a 10 ton liquid argon scintillation detector located at Los Alamos National Lab. The detector is located 23m downstream from the Lujan Facility's stopped pion source which will receive 2.25 * 10^22 POT in the ongoing 3 year run cycle. CCM is instrumented with 200 8-inch PMTs, 80% of which are coated in wavelength shifting tetraphenyl-butadiene, and 40 optically isolated 1-inch veto PMTs. The combination of PMTs coated in wavelength shifter and uncoated PMTs allows CCM to resolve both scintillation and Cherenkov light. Argon scintillation light peaks at 128nm, which requires the use of wavelength shifters into the visible spectrum for detection by the PMTs. The uncoated PMTs, however, will be more sensitive to the broad spectrum Cherenkov light and less sensitive to the UV scintillation light produced in argon. This combination of coated and uncoated PMTs, along with our 2 nsec timing resolution, enables event by event identification of Cherenkov light.

        Speaker: Darcy Newmark (Massachusetts Institute of Technology)
      • 71
        A more complete model of light emission in xenon-doped liquid argon
        Speaker: Prof. Douglas Fields (University of New Mexico)
    • 72
      Summary of the discussion sessions Auditorium


      Speakers: Laura Perez-Molina (CIEMAT), Ludovico Luzzi (CIEMAT)
    • 73
      Closing remarks Auditorium


      Speakers: Dr Ana Machado (Unicamp), Roberto Santorelli (CIEMAT)