BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:A proposal to use neutron captures as a source of ultra-low energy nuclear-recoils in liquid xenon DTSTART;VALUE=DATE-TIME:20210916T161500Z DTEND;VALUE=DATE-TIME:20210916T163000Z DTSTAMP;VALUE=DATE-TIME:20260418T125758Z UID:indico-contribution-8-36@indico.physics.ucsd.edu DESCRIPTION:Speakers: Chami Amarasinghe (University of Michigan)\nWe propo se a technique for an ultra-low energy nuclear-recoil measurement in liqui d xenon using thermal neutron capture. The measurement uses the recoils im parted to xenon nuclei during the de-excitation process following neutron capture\, where the promptly emitted $\\gamma$ cascade can leave the nucle i with up to $0.3$ keV$_\\text{nr}$ of recoil energy. A successful measure ment of the quanta yields below this point will contribute to a greater se nsitivity for liquid xenon experiments that will benefit from a lower ener gy threshold\, mainly those searching for light WIMPs and coherent neutrin o-nucleus scattering. We describe the proposed measurement and its feasibi lity for a small (sub-kilogram) LXe detector that is optimized for a high scintillation gain\, and a pulsed neutron source.\n\nhttps://indico.physic s.ucsd.edu/event/1/contributions/36/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/36/ END:VEVENT BEGIN:VEVENT SUMMARY:Latest Results from the Xenon Breakdown Apparatus DTSTART;VALUE=DATE-TIME:20210916T151500Z DTEND;VALUE=DATE-TIME:20210916T153000Z DTSTAMP;VALUE=DATE-TIME:20260418T125758Z UID:indico-contribution-8-11@indico.physics.ucsd.edu DESCRIPTION:Speakers: Reed Watson (University of California\, Berkeley)\nT he Liquid Xenon Time-Projection Chamber (LXe TPC) is a leading technology in the fields of dark matter direct detection and neutrinoless double-beta decay searches\, due in no small part to its scalability. The next genera tion of LXe TPCs intend to extend their drift lengths while maintaining th eir high operational electric fields (100s of Volts per cm). This increas e in high voltage requires understanding how the risk of electrostatic dis charge (ESD) correlates with various engineered quantities. To this end\, the Xenon Breakdown Apparatus (XeBrA)\, a 5 Liter spark chamber with adjus table large area electrodes and transparent viewports\, collected data on ESD in LXe under a variety of different conditions. Effects such as condit ioning\, pressure\, ramp rate\, stressed area\, and surface finish were in vestigated. Data regarding the production of light and charge preceding an ESD were collected\, along with novel position reconstruction of the asso ciated plasma streamers using a pair of high frame rate cameras. In this t alk\, I present preliminary results from XeBrA and discuss the evidence co llected for field-emission initiating breakdowns.\n\nhttps://indico.physic s.ucsd.edu/event/1/contributions/11/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/11/ END:VEVENT BEGIN:VEVENT SUMMARY:Proposal of a Geiger-geometry Single Phase Time Projection Chamber as Potential Detector Technique for next-generation large-scale dark matt er search detector DTSTART;VALUE=DATE-TIME:20210916T143000Z DTEND;VALUE=DATE-TIME:20210916T144500Z DTSTAMP;VALUE=DATE-TIME:20260418T125758Z UID:indico-contribution-8-10@indico.physics.ucsd.edu DESCRIPTION:Speakers: Qing Lin (University of Science and Technology of Ch ina)\nDual phase time projection chamber using liquid xenon as target mate rial is one of most successful detectors for dark matter direct search\, a nd has improved the sensitivities of searching for weakly interacting mass ive particles by almost five orders of magnitudes in past several decades. However\, it still remains a great challenge for dual phase liquid xenon time projection chamber to be used as the detector in next-generation dark matter search experiments (~50 tonne sensitive mass)\, in terms of reachi ng sufficiently high field strength for drifting electrons\, and sufficien tly low background rate. Here we propose a single phase liquid xenon time projection chamber with detector geometry similar to a Geiger counter\, as a potential detector technique for future dark matter search\, which trad es off field uniformity for less isolated charge signals. In this talk\, I will talk about the concept of such Geiger-geometry single phase TPC (GG- TPC). I’ll show preliminary studies of field simulation and signal recon struction\, which show that such single phase time projection chamber is t echnically feasible and can have sufficiently good signal reconstruction p erformance for dark matter direct search.\n\nhttps://indico.physics.ucsd.e du/event/1/contributions/10/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/10/ END:VEVENT BEGIN:VEVENT SUMMARY:A new high voltage cable feedthrough concept for future dark matte r and neutrino experiments DTSTART;VALUE=DATE-TIME:20210916T154500Z DTEND;VALUE=DATE-TIME:20210916T160000Z DTSTAMP;VALUE=DATE-TIME:20260418T125758Z UID:indico-contribution-8-46@indico.physics.ucsd.edu DESCRIPTION:Speakers: Luca Pagani (University of California at Davis)\nPhy sics experiments featuring liquid noble gas time projection chambers are b ecoming larger in scale. Consequently\, their high voltage (HV) requiremen ts have increased as well\, making conventional design HV feedthrough (FT) impracticable. A new concept for an HV cable FT usable in a cryogenic env ironment is presented in this talk. It features a co-extruded multi-layere d coaxial cable fabricated with a single material and relies on the abilit y to develop a plastic material with tunable resistivity.\n\nhttps://indic o.physics.ucsd.edu/event/1/contributions/46/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/46/ END:VEVENT BEGIN:VEVENT SUMMARY:Understanding the impact of high voltage electrodes on low-energy dark matter searches with the LZ dual phase xenon TPC DTSTART;VALUE=DATE-TIME:20210916T150000Z DTEND;VALUE=DATE-TIME:20210916T151500Z DTSTAMP;VALUE=DATE-TIME:20260418T125758Z UID:indico-contribution-8-59@indico.physics.ucsd.edu DESCRIPTION:Speakers: Ryan Linehan ()\nTo observe signals from low-energy nuclear recoils\, including WIMP-xenon scatters\, the LZ dark matter detec tor must maintain strong drift and extraction fields within its dual-phase xenon time projection chamber (TPC). These fields are established by a se t of four stainless steel wire mesh high voltage electrode grids that span the full width of the TPC. During operation at their design voltages\, th ese grids will achieve wire surface fields well above 20 kV/cm. These high fields can produce spurious charge signals and signals from real radioact ive decays with atypical light-to-charge ratios\, both of which can lead t o low-energy backgrounds in LZ science data. This talk will present studie s of possible grid contributions to electron backgrounds in the low-energy regime\, with a focus on two specific sources: field-induced emission and radiogenic emission.\n\nhttps://indico.physics.ucsd.edu/event/1/contribut ions/59/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/59/ END:VEVENT BEGIN:VEVENT SUMMARY:Detection of Electroluminescence in Liquid Xenon with a Radial Tim e Projection Chamber DTSTART;VALUE=DATE-TIME:20210916T144500Z DTEND;VALUE=DATE-TIME:20210916T150000Z DTSTAMP;VALUE=DATE-TIME:20260418T125758Z UID:indico-contribution-8-77@indico.physics.ucsd.edu DESCRIPTION:Speakers: Jianyang Qi (UCSD)\nThe dual-phase xenon Time Projec tion Chamber (TPC) is one of the most successful techniques for rare event searches. It detects both primary scintillation and ionization signals fr om particle interactions in liquid xenon (LXe) . The ionization electrons are converted into electroluminescence in the gas xenon\, subsequently det ected by the same photo-sensors for the primary scintillation. However\, i t gradually becomes more and more challenging to build the TPCs with very large diameter while requiring sub-mm flatness of the gas gap. Here we dev eloped a Radial TPC (RTPC) which can create and detect the electroluminesc ence directly in liquid xenon. It can simplify the design of the TPC by re placing the large diameter electrodes with a single wire in the axial cent er. The design of a liquid xenon RTPC and its first performance will be pr esented.\n\nhttps://indico.physics.ucsd.edu/event/1/contributions/77/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/77/ END:VEVENT BEGIN:VEVENT SUMMARY:Prospects of S2 analysis in single-phase liquid xenon TPCs DTSTART;VALUE=DATE-TIME:20210916T141500Z DTEND;VALUE=DATE-TIME:20210916T143000Z DTSTAMP;VALUE=DATE-TIME:20260418T125758Z UID:indico-contribution-8-80@indico.physics.ucsd.edu DESCRIPTION:Speakers: Fabian Kuger (Albert-Ludwigs Universität Freiburg)\ nProportional scintillation in liquid is a possible alternative scheme for charge-to-light signal conversion in future large-size liquid xenon TPCs. Based on detailed simulations we explore the implications on charge signa l (S2) analysis arising from this fast scintillation process. The peaked s ignals allow precise reconstruction of the individual electrons and thus a quantized measure of the S2 strength. Counting the number of electrons si gnificantly improves the S2 resolution for small signals\, relevant for lo w-energy ER studies and sub-GeV WIMP searches. The direct measurement of t he electron arrival times improves S2-only reconstruction of the event dep th and allows for powerful discrimination between single site and multiple site interactions. We discuss these prospects in the context of a future multi-ton liquid xenon experiment such as DARWIN\, assuming a single-phase design with minimal change compared to state-of-the-art dual-phase detect ors.\n\nhttps://indico.physics.ucsd.edu/event/1/contributions/80/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/80/ END:VEVENT BEGIN:VEVENT SUMMARY:Dielectric Strength of Noble and Quenched Gases for High Pressure Time Projection Chambers DTSTART;VALUE=DATE-TIME:20210916T153000Z DTEND;VALUE=DATE-TIME:20210916T154500Z DTSTAMP;VALUE=DATE-TIME:20260418T125758Z UID:indico-contribution-8-85@indico.physics.ucsd.edu DESCRIPTION:Speakers: Logan Norman ()\nDielectric breakdown strength is on e of the critical performance metrics for gases and mixtures used in large \, high pressure gas time projection chambers. We have experimentally stud ied dielectric breakdown strengths of several important time projection ch amber working gases and gas-phase insulators over the pressure range 100 m bar to 10 bar\, and gap sizes ranging from 0.1to 10 mm. Gases characterize d include argon\, xenon\, CO2\, CF4\, and mixtures 90-10 argon-CH4\,90-10 argon-CO2and 99-1 argon-CF4. We developed a theoretical model for high vol tage breakdown based on microphysical simulations that use PyBoltz electro n swarm Monte Carlo results as input to Townsend- and Meek-like discharge criteria. This model is shown to be highly predictive at high pressure\, o ut-performing traditional Paschen-Townsend and Meek-Raether models signifi cantly. At lower pressure-times-distance\, the Townsend-like model is an e xcellent description for noble gases whereas the Meek-like model provides a highly accurate prediction for insulating gases.\n\nhttps://indico.physi cs.ucsd.edu/event/1/contributions/85/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/85/ END:VEVENT BEGIN:VEVENT SUMMARY:Low Threshold Operation of the Scintillating Xenon Bubble Chamber DTSTART;VALUE=DATE-TIME:20210916T160000Z DTEND;VALUE=DATE-TIME:20210916T161500Z DTSTAMP;VALUE=DATE-TIME:20260418T125758Z UID:indico-contribution-8-95@indico.physics.ucsd.edu DESCRIPTION:Speakers: Matthew Bressler (Drexel University)\nA scintillatin g bubble chamber with pure xenon was first operated in 2016 and has previo usly demonstrated coincident bubble nucleation and scintillation detection at thermodynamic thresholds above 4 keV. We now report on operation of th e xenon bubble chamber at thermodynamic thresholds as low as 0.5 keV\, inc luding tests of bubble nucleation associated with gammas\, and sensitivity to low energy neutrons from a $^{88}$Y-Be photoneutron source at threshol ds around 1 keV. Additionally\, these results again demonstrate coincident bubble nucleation and scintillation with 252Cf and background neutrons\, and the scintillation channel allows us to make an efficient background-re ducing cut for a nuclear recoil efficiency analysis\, which is ongoing.\n\ nhttps://indico.physics.ucsd.edu/event/1/contributions/95/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/95/ END:VEVENT BEGIN:VEVENT SUMMARY:Mind the (gas) gap: a single-phase liquid xenon TPC DTSTART;VALUE=DATE-TIME:20210916T140000Z DTEND;VALUE=DATE-TIME:20210916T141500Z DTSTAMP;VALUE=DATE-TIME:20260418T125758Z UID:indico-contribution-8-2@indico.physics.ucsd.edu DESCRIPTION:Speakers: Adam Brown (University of Freiburg)\nOne of the most significant challenges for future dual-phase xenon TPCs is achieving the high\, uniform electric field needed in the gas layer. One solution is to avoid using gaseous xenon and instead to create the secondary scintillatio n within the liquid itself\, in a single-phase xenon TPC. Within micrometr es of thin wires\, the electric field is high enough to enable VUV scintil lation. Avoiding the gas gap can provide a workaround to some of the techn ical challenges facing larger TPCs. At the same time\, it opens up new det ector design possibilities by relaxing the requirement that electrons are drifted upwards and facilitates analysis based on counting electrons. We d iscuss some of these advantages and present experimental results from a sm all single-phase demonstrator TPC with 10 µm anode wires.\n\nhttps://indi co.physics.ucsd.edu/event/1/contributions/2/ LOCATION: URL:https://indico.physics.ucsd.edu/event/1/contributions/2/ END:VEVENT END:VCALENDAR