Nuclear-recoil energy scale in CDMS II silicon dark-matter detectors (original) (raw)
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Neutron capture-induced silicon nuclear recoils for dark matter and CE$\nu$NS
arXiv (Cornell University), 2023
Following neutron capture in a material there will be prompt nuclear recoils in addition to the gamma cascade. The nuclear recoils that are left behind in materials are generally below 1 keV and therefore in the range of interest for dark matter experiments and CEνNS studies-both as backgrounds and calibration opportunities. Here we obtain the spectrum of prompt nuclear recoils following neutron capture for silicon.
Impact of Low-Energy Response to Nuclear Recoils in Dark Matter Detectors
arXiv: Instrumentation and Detectors, 2015
We report an absolute energy response function to electronic and nuclear recoils for germanium and liquid xenon detectors. As a result, we show that the detection energy threshold of nuclear recoils for a dual-phase xenon detector can be a few keV for a given number of detectable photoelectrons. We evaluate the average energy expended per electron-hole pair to be sim\simsim3.32 eV, which sets a detection energy threshold of sim\simsim2.15 keV for a germanium detector at 50 mini-Kelvin at 69 volts with a primary phonon frequency of 1 THz. The Fano factors of nuclear and electronic recoils that constrain the capability for discriminating nuclear recoils below 2-3 keV recoil energy for both technologies are different.
Silicon Detector Dark Matter Results from the Final Exposure of CDMS II
Physical Review Letters, 2013
We report results of a search for Weakly Interacting Massive Particles (WIMPS) with the silicon detectors of the CDMS II experiment. This blind analysis of 140.2 kg-days of data taken between July 2007 and September 2008 revealed three WIMP-candidate events with a surface-event background estimate of 0.41 +0.20 −0.08 (stat.) +0.28 −0.24 (syst.). Other known backgrounds from neutrons and 206 Pb are limited to < 0.13 and < 0.08 events at the 90% confidence level, respectively. The exposure of this analysis is equivalent to 23.4 kg-days for a recoil energy range of 7-100 keV for a WIMP of mass 10 GeV/c 2 . The probability that the known backgrounds would produce three or more events in the signal region is 5.4%. A profile likelihood ratio test of the three events that includes the measured recoil energies gives a 0.19% probability for the known-background-only hypothesis when tested against the alternative WIMP+background hypothesis. The highest likelihood occurs for a WIMP mass of 8.6 GeV/c 2 and WIMP-nucleon cross section of 1.9×10 −41 cm 2 .
Response of the XENON100 dark matter detector to nuclear recoils
Physical Review D, 2013
Results from the nuclear recoil calibration of the XENON100 dark matter detector installed underground at the Laboratori Nazionali del Gran Sasso (LNGS), Italy are presented. Data from measurements with an external 241 AmBe neutron source are compared with a detailed Monte Carlo simulation which is used to extract the energy dependent charge-yield Qy and relative scintillation efficiency L eff . A very good level of absolute spectral matching is achieved in both observable signal channels -scintillation S1 and ionization S2 -along with agreement in the 2-dimensional particle discrimination space. The results confirm the validity of the derived signal acceptance in earlier reported dark matter searches of the XENON100 experiment.
Journal of Low Temperature Physics, 2008
The Cryogenic Dark Matter Search (CDMS) experiment is searching for Weakly Interacting Massive Particles (WIMPs) using detectors with the ability to discriminate between candidate (nuclear recoil) and background (electron recoil) events by measuring both phonon and ionization signals from recoils in the detector crystals. As CDMS scales up to greater WIMP sensitivity, it is necessary to increase the detector mass and further improve background discrimination. CDMS is engaged in ongoing fabrication and development of new detector designs in order to meet these criteria for the proposed SuperCDMS experiment. Thicker detector prototypes have been produced with new photolithographic masks. These masks have greater surface coverage of the quasi particle trap and transition edge sensor system to provide J Low Temp Phys (2008) 151: 211-215 superior athermal phonon collection. Results from continuing laboratory tests are presented which already indicate improvement in discrimination parameters. Keywords SuperCDMS · Dark matter PACS 95.35.+d · 14.80.Ly · 29.40.Vj · 85.25.Oj · 73.61.Jc · 85.25.-j · 74.78.-w · 85.25.Oj
Results on sub-GeV dark matter from a 10 eV threshold CRESST-III silicon detector
Physical review, 2023
We present limits on the spin-independent interaction cross section of dark matter particles with silicon nuclei, derived from data taken with a cryogenic calorimeter with 0.35 g target mass operated in the CRESST-III experiment. A baseline nuclear recoil energy resolution of ð1.36 AE 0.05Þ eV nr , currently the lowest reported for macroscopic particle detectors, and a corresponding energy threshold of ð10.0 AE 0.2Þ eV nr have been achieved, improving the sensitivity to light dark matter particles with masses below 160 MeV=c 2 by a factor of up to 20 compared to previous results. We characterize the observed low energy excess, and we exclude noise triggers and radioactive contaminations on the crystal surfaces as dominant contributions.
arXiv (Cornell University), 2016
The Large Underground Xenon (LUX) experiment is a dual-phase liquid xenon time projection chamber (TPC) operating at the Sanford Underground Research Facility in Lead, South Dakota. A calibration of nuclear recoils in liquid xenon was performed in situ in the LUX detector using a collimated beam of mono-energetic 2.45 MeV neutrons produced by a deuterium-deuterium (D-D) fusion source. The nuclear recoil energy from the first neutron scatter in the TPC was reconstructed using the measured scattering angle defined by double-scatter neutron events within the active xenon volume. We measured the absolute charge (Qy) and light (Ly) yields at an average electric field of 180 V/cm for nuclear recoil energies spanning 0.7 to 74 keV and 1.1 to 74 keV, respectively. This calibration of the nuclear recoil signal yields will permit the further refinement of liquid xenon nuclear recoil signal models and, importantly for dark matter searches, clearly demonstrates measured ionization and scintillation signals in this medium at recoil energies down to O(1 keV).
New results from the Cryogenic Dark Matter Search experiment
Physical Review D, 2003
Using improved Ge and Si detectors, better neutron shielding, and increased counting time, the Cryogenic Dark Matter Search (CDMS) experiment has obtained stricter limits on the cross section of weakly interacting massive particles (WIMPs) elastically scattering from nuclei. Increased discrimination against electromagnetic backgrounds and reduction of the neutron flux confirm WIMPcandidate events previously detected by CDMS were consistent with neutrons and give limits on spin-independent WIMP interactions which are > 2× lower than previous CDMS results for high WIMP mass, and which exclude new parameter space for WIMPs with mass between 8-20 GeV c −2 .
Physical Review D
Liquid xenon-based direct detection dark matter experiments have recently expanded their searches to include high-energy nuclear recoil events as motivated by effective field theory dark matter and inelastic dark matter interaction models, but few xenon recoil calibrations above 100 keV are currently available. In this work, we measured the scintillation and ionization yields of xenon recoils up to 426 keV. The experiment uses 14.1 MeV neutrons to scatter off xenon in a compact liquid xenon time projection chamber and produce quasi-monoenergetic xenon recoils between 39 keV and 426 keV. We report the xenon recoil responses and their electric field-dependence for recoil energies up to 306 keV; due to the low event statistics and the relatively mild field dependence, the yield values at higher energies are reported as the average of xenon responses for electric fields between 0.2-2.0 kV/cm. This result will enable xenon-based dark matter experiments to significantly increase their high energy dark matter sensitivities by including energy regions that were previously inaccessible due to lack of calibrations.