INPA

VIRTUAL INPA SEMINAR | Andreas Biekert (UC Berkeley)
2021-10-01 12:00 - 13:00 (America/Los_Angeles)
Speaker: Andreas Biekert (UC Berkeley)
Title: Scintillation Yield From Electronic and Nuclear Recoils In Superfluid 4He
Abstract:
HeRALD is a proposed sub-GeV scale dark matter detector based on a superfluid 4He target and transition edge sensor readout, supported as part of the TESSERACT project. Possible signal channels available for readout include prompt photons, triplet excimers, and roton and phonon quasiparticles, but the relative strength of these signals for low energy nuclear recoils requires experimental verification. We have measured the superfluid 4He scintillation yield at 1.75 K from nuclear recoils in the range of 50-1100 keV using a 16 cm3 target volume read out by six superfluid-immersed PMTs. Elastic scattering of 2.8 MeV neutrons produced by a deuterium-deuterium neutron generator and Compton scattering of 662 keV 137Cs gamma rays were used to determine the relative scintillation yield. Yields of both prompt and delayed scintillation components were measured and compared to a semi-empirical response model based on helium-helium and electron-helium scattering cross sections. We also discuss the development of a 24 keV neutron source to extend our measurements to smaller nuclear recoil energies.
Join Zoom Meeting https://lbnl.zoom.us/j/91625792208?pwd=[REDACTED]
Meeting ID: 916 2579 2208
Passcode: [REDACTED]

VIRTUAL INPA SEMINAR | Kevin Thieme (Univ. of Zurich)
2021-10-08 12:00 - 13:00
Speaker: Kevin Thieme (University of Zurich)
Title: A Measurement of the Mean Electronic Excitation Energy of Liquid Xenon

Abstract:
Detectors using liquid xenon as target are widely deployed in rare event searches. Conclusions on the interacting particle rely on a precise reconstruction of the deposited energy which requires calibrations of the energy scale of the detector by means of radioactive sources. However, a microscopic calibration, i.e. the translation from the number of excitation quanta into deposited energy, also necessitates good knowledge of the energy required to produce single scintillation photons or ionisation electrons in liquid xenon. The sum of these excitation quanta is directly proportional to the deposited energy in the target. The proportionality constant is the mean excitation energy and is commonly known as W-value. Here we present a measurement of the W-value with electronic recoil interactions in a small dual-phase xenon time projection chamber with a hybrid (photomultiplier tube and silicon photomultipliers) photosensor configuration. Our result is based on calibrations at O(1–10 keV) with internal 37-Ar and 83m-Kr sources and single electron events. We obtain a value of W=(11.5 +0.2 -0.3 (syst.)) eV, with negligible statistical uncertainty, which is lower than previously measured at these energies. If further confirmed, our result will be relevant for modelling the absolute response of liquid xenon detectors to particle interactions.

Join Zoom Meeting https://lbnl.zoom.us/j/93376704948?pwd=[REDACTED]
Meeting ID: 933 7670 4948
Passcode: [REDACTED]

VIRTUAL INPA SEMINAR | Peter Taylor (NASA Jet Propulsion Laboratory )
2021-10-15 12:00 - 13:00
Speaker: Peter Taylor (NASA Jet Propulsion Laboratory )
Title: The RSD Sorting Hat
Abstract:
Redshift-space distortions (RSD) and weak lensing (WL) studies yield some of the tightest cosmological constraints. Large overlapping data sets from Euclid, the Rubin Observatory, the Roman Space Science Telescope and the Dark Energy Spectroscopic Instruments will enable a joint RSD/WL analysis. Such an analysis could significantly outperform WL and RSD analyses performed in isolation. In this talk I show how to optimally extract information from the RSD signal using angular statistics. This is a first step towards combing WL and RSD.

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https://lbnl.zoom.us/j/91769253333?pwd=[REDACTED]
Meeting ID: 917 6925 3333
Passcode: [REDACTED]

VIRTUAL INPA SEMINAR | Noah Kurinsky (SLAC )
2021-10-22 12:00 - 13:00
Speaker: Noah Kurinsky (SLAC)
Title: Quantum Sensors for Direct Detection of Sub-GeV Dark Matter
Abstract:
Over the last 20 years, searches for dark matter above the proton mass have advanced significantly across direct and indirect searches, but sub-GeV dark matter has until recently been comparatively unprobed. In this talk, I will discuss the state of the Sub-GeV direct detection field, and prospects for applying quantum measurement techniques to lowering mass thresholds for new searches with event thresholds at the eV-scale. I will then discuss the outlook for the field in the next 5-10 years, in the context of synergy with ongoing research in materials science and quantum information science. The goal over the next decade is to run background-free dark matter searches at gram-year exposures with meV-scale thresholds, an exciting challenge that requires a broad range of expertise, and comes with enormous scientific discovery potential.

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https://lbnl.zoom.us/j/98007893520?pwd=[REDACTED]
Meeting ID: 980 0789 3520
Passcode: [REDACTED]

VIRTUAL INPA SEMINAR | Luca Pagani (UC Davis )
2021-10-29 12:00 - 13:00
Speaker: Luca Pagani (UC Davis)
Title: First Results From The ARTIE Experiment
Abstract:
A measurement of the transmission coefficient for neutrons through a thick (~3 atoms/b) liquid natural argon target in the energy range 30-70 keV was performed by the Argon Resonance Transmission Interaction Experiment (ARTIE) using a time of flight neutron beam at Los Alamos National Laboratory. In this energy range theory predicts an anti-resonance in the 40-Ar cross section near 57 keV, but the existing data, coming from an experiment performed in the 90s (Winters. et al.), does not support this. This discrepancy gives rise to significant uncertainty in the penetration depth of neutrons through liquid argon, an important parameter for next generation neutrino and dark matter experiments.In this talk, the first results from the ARTIE experiment will be presented. The ARTIE measurement of the total cross section as a function of energy confirms the existence of the anti-resonance near 57 keV, but not as deep as the theory prediction.

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https://lbnl.zoom.us/j/96839979915pwd=[REDACTED]
Meeting ID: 968 3997 9915
Passcode: [REDACTED]
