BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Band and Time - Resolved Scintillation for Alpha and Beta Particle s in Xenon\, as a Function of Pressure and Electric Field DTSTART;VALUE=DATE-TIME:20210915T141500Z DTEND;VALUE=DATE-TIME:20210915T143000Z DTSTAMP;VALUE=DATE-TIME:20260811T171844Z UID:indico-contribution-5-72@indico.physics.ucsd.edu DESCRIPTION:Speakers: Sara Leardini (IGFAE\, Universidade de Santiago de C ompostela)\nIn standard conditions\, Xenon is the only gaseous element wit h a naturally occurring isotope undergoing double-beta decay. Hence exploi ting a gaseous TPC as a tool for accurately reconstructing the topology of bb0nu events is very natural. When considering i) sensitivity to the life time of the decay and ii) energy resolution to separate it from regular bb 2nu events\, a high pressure electroluminescence TPC self-suggests. At the moment\, the NEXT TPC is the most advanced implementation of this idea\, relying deeply on common-wisdom assumptions like the monochromaticity of b oth primary and secondary scintillation (around 172nm)\, the lack of charg e recombination for beta-events\, or the validity of density-scalings for secondary scintillation. Looking into the future\, the unambiguous elucida tion of these phenomena becomes necessary in view of the upcoming ton and multi-ton scale experiments aimed at completely exploring the inverted hie rarchy of neutrino masses.\n\nMotivated by this\, we conducted systematic measurements of S1 and S2\nsignals in a mini-TPC read out with wires\, for varying pressures (1-10bar)\, pressure-reduced electric fields (0-100V/cm /bar) and wire voltages (up to 4kV). Systematic measurements of the time c onstants and scintillation yields obtained in these conditions will be pre sented\, for alpha and beta sources in the VUV\, UV and visible bands\, an d its impact on next generation xenon TPCs discussed.\n\nhttps://indico.ph ysics.ucsd.edu/event/1/contributions/72/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/72/ END:VEVENT BEGIN:VEVENT SUMMARY:Electronic versus nuclear recoil discrimination in liquid xenon wi th PIXeY DTSTART;VALUE=DATE-TIME:20210915T150000Z DTEND;VALUE=DATE-TIME:20210915T151500Z DTSTAMP;VALUE=DATE-TIME:20260811T171844Z UID:indico-contribution-5-32@indico.physics.ucsd.edu DESCRIPTION:Speakers: Vetri Velan (University of California\, Berkeley)\nT he two-phase liquid/gas xenon time projection chamber is one of the leadin g technologies for dark matter direct detection. A crucial part of using t his technology is being able to classify energy deposits as nuclear recoil s (NR) or electronic recoils (ER). This allows upcoming experiments like X ENONnT and LZ to mitigate ER backgrounds like Rn daughters and solar neutr inos. I will present an analysis of ER-NR discrimination\, using data from the PIXeY (Particle Identification in Xenon at Yale) experiment. PIXeY wa s an R&D-scale xenon TPC that operated at drift fields between 50 and 2000 V/cm\; its data allows us to study discrimination across this wide range of fields\, as well as its dependence on recoil energy.\n\nhttps://indico. physics.ucsd.edu/event/1/contributions/32/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/32/ END:VEVENT BEGIN:VEVENT SUMMARY:Characterization of alpha and beta interactions in liquid xenon DTSTART;VALUE=DATE-TIME:20210915T143000Z DTEND;VALUE=DATE-TIME:20210915T144500Z DTSTAMP;VALUE=DATE-TIME:20260811T171844Z UID:indico-contribution-5-38@indico.physics.ucsd.edu DESCRIPTION:Speakers: Florian Jörg (Max-Planck-Insitut für Kernphysik)\n Experiments used for rare-event searches have seen an impressive increase of sensitivity over the past decades. Among the most sensitive detector ty pes used in direct dark matter searches are dual-phase xenon time projecti on chambers (TPCs). To develop a signal model for such detectors\, the res ponse of the medium to interactions of different particle types needs to b e known to a high accuracy. While several measurements for interactions of electrons\, photons and neutrons were reported in the past\, the literat ure is sparse when it comes to the interaction of alpha particles with liq uid xenon.\n\nThe Heidelberg Xenon (HeXe) dual-phase xenon TPC has been us ed to study the relative scintillation and ionization yield of low energy electrons from a $\\mathrm{^{83m}Kr}$ source\, as well as from alpha parti cles emitted by dissolved $\\mathrm{^{222}Rn}$. Furthermore\, a measuremen t of the electron drift velocity has been carried out. The different elect ric field configurations applied during the measurements were simulated by a detailed three dimensional model of the TPC using COMSOL Multiphysics. The measurements span over a wide range of fields within 7.5$\\\,$V/cm up to 1.64$\\\,$kV/cm\, whereas special emphasis was put on the low-field reg ime.\n\nhttps://indico.physics.ucsd.edu/event/1/contributions/38/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/38/ END:VEVENT BEGIN:VEVENT SUMMARY:Scintillation yield from electronic and nuclear recoils in superfl uid helium-4 DTSTART;VALUE=DATE-TIME:20210915T151500Z DTEND;VALUE=DATE-TIME:20210915T153000Z DTSTAMP;VALUE=DATE-TIME:20260811T171844Z UID:indico-contribution-5-56@indico.physics.ucsd.edu DESCRIPTION:Speakers: Ryan Smith (UC Berkeley)\nSuperfluid He-4 is a promi sing target material for direct detection of low mass (\n\nhttps://indico. physics.ucsd.edu/event/1/contributions/56/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/56/ END:VEVENT BEGIN:VEVENT SUMMARY:Scintillation and optical properties of xenon-doped liquid argon DTSTART;VALUE=DATE-TIME:20210915T144500Z DTEND;VALUE=DATE-TIME:20210915T150000Z DTSTAMP;VALUE=DATE-TIME:20260811T171844Z UID:indico-contribution-5-54@indico.physics.ucsd.edu DESCRIPTION:Speakers: Christoph Vogl (Technical University of Munich)\nLiq uid argon (LAr) is widely employed as a scintillator in rare-event searche s. Its optical and scintillation properties\, as well as the impact of imp urities\, are being studied extensively by many groups world-wide. LAr sci ntillation light exhibits a main emission wavelength of 128 nm\, which mak es propagation and detection challenging because of short attenuation leng ths and low quantum efficiencies of photo sensors in the VUV spectral rang e. \n\nPreviously\, we have determined the attenuation length of purified liquid argon for its own scintillation light to be larger than 110 cm at a wavelength of 128 nm [1\, 2]. Already in 1982 Kubota et al. [3] investiga ted the impact of xenon doping of LAr. Recently\, we have studied the emis sion spectrum and time distribution dependent on the xenon concentration [ 4]. \n\nHere\, we present our latest study of xenon-doped LAr with focus o n the primary photon yield\, the effective triplet lifetime and attenuatio n length\, with xenon concentrations ranging from 3 ppm to 300 ppm. The sc intillation and optical properties were measured simultaneously with the * LLAMA* [5] instrument operated inside *SCARF*\, a 1 ton LAr test stand\, a nd the xenon concentrations using *IDEFIX*\, a dedicated mass spectrometer setup.\n\n[1] A. Neumeier et al. “Attenuation of Vacuum Ultraviolet Lig ht in Liquid Argon”. In: Eur. Phys. J. C72.10 (Oct. 2012).\n\n[2] A. Neu meier et al. “Attenuation of Vacuum Ultraviolet Light in Pure and Xenon- Doped Liquid Argon — An Approach to an Assignment of the near-Infrared E mission from the Mixture”. In: EPL 111.1 (July 2015).\n\n[3] Shinzou Kub ota et al. “Liquid and Solid Argon\, Krypton and Xenon Scintillators”. In: Nucl. Inst. Meth. Phys. Res. 196.1 (May 1982).\n\n[4] A. Neumeier et al. “Intense Vacuum Ultraviolet and Infrared Scintillation of Liquid Ar- Xe Mixtures”. In: EPL 109.1 (Jan. 2015).\n\n[5] Mario Schwarz et al. “ Liquid Argon Instrumentation and Monitoring in LEGEND-200”. In: ANIMMA 2 021 (July 2021)\n\nhttps://indico.physics.ucsd.edu/event/1/contributions/5 4/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/54/ END:VEVENT BEGIN:VEVENT SUMMARY:Preliminary Tests of Dual-Phase Xenon-Doped Argon Mixtures in the CHILLAX Detector DTSTART;VALUE=DATE-TIME:20210915T153000Z DTEND;VALUE=DATE-TIME:20210915T154500Z DTSTAMP;VALUE=DATE-TIME:20260811T171844Z UID:indico-contribution-5-41@indico.physics.ucsd.edu DESCRIPTION:Speakers: Ethan Bernard (Lawrence Livermore National Laborator y)\nUtilizing xenon as a dopant at the $10^{-5}$ level in the gas region o f a dual-phase argon time projection chamber (TPC) presents the enticing p rospects of faster and longer wavelength electroluminescence response to i onization electrons. This light can then be directly detected by UV-sensit ive SiPMs without the use of fluorescent wavelength-shifting materials. Th ese advantages would improve sensitivity to low energy nuclear recoils\, w hich kinetically favor argon over xenon\; examples include coherent neutri no-nucleus scattering (CENNS)\, and the possibility of light WIMP dark mat ter interactions. However\, operating such a detector imposes the novel te chnical requirement of cryogenic systems which must prevent xenon from par titioning between the liquid and gas phases. This has compelled the develo pment of CoHerent Ionization Limits in Liquid Argon and Xenon (CHILLAX)\, a new xenon-doped\, dual-phase argon detector. This talk will survey the p hysics implications of xenon-doped argon TPCs\, and describe the special c ooling and circulation systems in CHILLAX. It will conclude with an overvi ew of the current status of the detector and recent cryogenic tests perfor med..\n\nPrepared by LLNL under Contract DE-AC52-07NA27344. Release number LLNL-ABS-824388. The SCGSR program is administered by ORISE under Contrac t DE-SC0014664.\n\nhttps://indico.physics.ucsd.edu/event/1/contributions/4 1/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/41/ END:VEVENT BEGIN:VEVENT SUMMARY:Absolute experimental primary scintillation yield in Xe for electr ons and alpha particles DTSTART;VALUE=DATE-TIME:20210915T140000Z DTEND;VALUE=DATE-TIME:20210915T141500Z DTSTAMP;VALUE=DATE-TIME:20260811T171844Z UID:indico-contribution-5-39@indico.physics.ucsd.edu DESCRIPTION:Speakers: C. M. B. Monteiro (Departament of Physics\, Universi ty of Coimbra)\nXenon scintillation has been widely used in recent particl e physics experiments. However\, information on primary scintillation yiel d in the absence of recombination is still scarce and dispersed. The mean energy required to produce a VUV scintillation photon (Wsc) in gaseous Xe has been measured to be in the range of 30-120 eV. Lower Wsc-values are of ten reported for alpha particles when compared to those for electrons prod uced by gamma or x-rays\, being this difference still not fully understood .\nWe performed a systematic experimental study of the absolute primary sc intillation yield in Xe at 1.2 bar\, using a Gas Proportional Scintillatio n Counter. The simulation model of the detector's geometric efficiency was benchmarked through the primary and secondary scintillation produced at d ifferent distances from the photosensor. Wsc-values were obtained for gamm a- and x-rays with energies in the range of 5.9-60 keV\, and for 2-MeV alp ha particles. No significant differences were found in the values for alph a particles and for electrons.\n\nAcknowledgment\nThis work is funded by F EDER\, through the Programa Operacional Factores de Competitividade — CO MPETE and by National funds through FCT - Fundação para a Ciência e Tec nologia\, Lisbon\, Portugal\, in the frame of project UID/FIS/04559/2020 (LIBPhys).\n\nhttps://indico.physics.ucsd.edu/event/1/contributions/39/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/39/ END:VEVENT END:VCALENDAR