https://biblio.ugent.be/publication/685594/file/1130605.pdf

Review of Particle Physics

/pdf/review-of-particle-physics-1996-1997-jeg703df6k.pdf

Review of Particle Physics, 1996-1997

The XENON1T experiment is currently in the commissioning phase at the Laboratori Nazionali del Gran Sasso, Italy. In this article we study the experiment's expected sensitivity to the spin-independent WIMP-nucleon interaction cross section, based on Monte Carlo predictions of the electronic and nuclear recoil backgrounds. The total electronic recoil background in 1 tonne fiducial volume and (1, 12) keV electronic recoil equivalent energy region, before applying any selection to discriminate between electronic and nuclear recoils, is (1.80 ± 0.15) · 10(−)(4) (kg·day·keV)(−)(1), mainly due to the decay of (222)Rn daughters inside the xenon target. The nuclear recoil background in the corresponding nuclear recoil equivalent energy region (4, 50) keV, is composed of (0.6 ± 0.1) (t·y)(−)(1) from radiogenic neutrons, (1.8 ± 0.3) · 10(−)(2) (t·y)(−)(1) from coherent scattering of neutrinos, and less than 0.01 (t·y)(−)(1) from muon-induced neutrons. The sensitivity of XENON1T is calculated with the Profile Likelihood Ratio method, after converting the deposited energy of electronic and nuclear recoils into the scintillation and ionization signals seen in the detector. We take into account the systematic uncertainties on the photon and electron emission model, and on the estimation of the backgrounds, treated as nuisance parameters. The main contribution comes from the relative scintillation efficiency Script L(eff), which affects both the signal from WIMPs and the nuclear recoil backgrounds. After a 2 y measurement in 1 t fiducial volume, the sensitivity reaches a minimum cross section of 1.6 · 10(−)(47) cm(2) at m(χ) = 50 GeV/c(2).

/pdf/physics-reach-of-the-xenon1t-dark-matter-experiment-4nlp7ku3x2.pdf

Physics reach of the XENON1T dark matter experiment

DARk matter WImp search with liquid xenoN (DARWIN(2)) will be an experiment for the direct detection of dark matter using a multi-ton liquid xenon time projection chamber at its core. Its primary g ...

/pdf/darwin-towards-the-ultimate-dark-matter-detector-2xp1zbo9d7.pdf

DARWIN: towards the ultimate dark matter detector

A review and new data are presented on the absolute photon yield emitted by "classical" (NaI(Tl/sup +/), CsI(Tl/sup +/), CsI(Na/sup +/), CaF/sub 2/(Eu/sup 2+/), Bi/sub 4/Ge/sub 3/O/sub 12/, and CdWO/sub 4/) and "modern" (BaF/sub 2/, Gd/sub 2/SiO/sub 5/(Ce/sup 3+/), YAlO/sub 3/(Ce/sup 3+/), Lu/sub 2/SiO/sub 5/(Ce/sup 3+/), Lu/sub 3/Al/sub 5/O/sub 12/(Sc/sup 3+/), and K/sub 2/LaCl/sub 5/(Ce/sup 3+/)) scintillation crystals after absorption of X-rays and /spl gamma/-rays of energies ranging from 5 keV to 1 MeV. Factors influencing the energy resolution with which high energy photons can be detected with scintillator-photomultiplier combinations are reviewed. Attention is especially focused on the effects of nonproportionality in the scintillation response on the energy resolution.

/pdf/non-proportionality-in-the-scintillation-response-and-the-4r1b0gb4nt.pdf

Non-proportionality in the scintillation response and the energy resolution obtainable with scintillation crystals

Measurements were made of the average energy $W$ per ion pair formed in liquid xenon by internal-conversion electrons from $^{207}\mathrm{Bi}$. We observed voltage pulses resulting from electron collection either in liquid xenon or in a gaseous mixture of argon (95%) and methane (5%). The relative pulse heights for the two materials determine the ratio of the $W$ values. Using the known $W$ for the gaseous mixture, we obtained a liquid-xenon $W$ of 15.6 \ifmmode\pm\else\textpm\fi{} 0.3 eV. This value is considerably smaller than the gas-phase values, 21.5 or 21.9 eV. For interpretation, we adapted Platzman's energy-balance equation to liquids, assuming a conduction-band picture. Theoretical values thus calculated agree well with experiment.

Average energy expended per ion pair in liquid xenon

An electric-field effect on the luminescence of liquid argon and xenon excited by $^{207}\mathrm{Bi}$ internal-conversion electrons has been studied. A decrease in the luminescence was observed (67% at 10 kV/cm for liquid argon and 74% at 12.7 kV/cm for liquid xenon relative to the intensity without an applied field), and is explained by the escape of electrons and holes before recombination. This provides strong evidence for the existence of the recombination luminescence. Quantum efficiencies of recombination and self-trapped exciton luminescence are briefly considered.

Recombination luminescence in liquid argon and in liquid xenon

Scintillation yields (scintillation intensity per unit absorbed energy) in liquid argon for ionizing particles are reviewed as a function of LET for the particles. The maximum scintillation yield, which is obtained for relativistic heavy ions from Ne to La, is about 1.2 times larger than that for gamma rays in NaI(Tl) crystal. In the low LET region, the scintillation yields for relativistic electrons, protons and He ions are 10–20% lower than the maximum yield. This tendency can be explained by taking into account the existence of the electrons which have escaped from their parent ions. In the high LET region, a quenching effect due to high ionization density is observed for alpha particles, fission fragments and relativistic Au ions.

Let Dependence of Scintillation Yields in Liquid Argon

Using recent scintillation data of liquid argon and xenon, the numbers of photons emitted in both liquids have been estimated. The ideal photon yields are 5.1 × 10 4 photons/MeV for liquid argon and 6.8 × 10 4 photons/MeV for liquid xenon. The photon yields due to 1 MeV electrons are 4.0 × 10 4 photons and 4.2 × 10 4 photons for respective liquids. These numbers are almost the same as that of a NaI(Tl) crystal.

Estimation of absolute photon yields in liquid argon and xenon for relativistic (1 MeV) electrons

Drift velocities of electrons, saturation characteristics of ionization and W-values for conversion electrons in liquid argon, liquid argon-gas mixtures and liquid xenon

Eido Shibamura

Papers

Average energy expended per ion pair in liquid xenon

Recombination luminescence in liquid argon and in liquid xenon

Let Dependence of Scintillation Yields in Liquid Argon

Estimation of absolute photon yields in liquid argon and xenon for relativistic (1 MeV) electrons

Drift velocities of electrons, saturation characteristics of ionization and W-values for conversion electrons in liquid argon, liquid argon-gas mixtures and liquid xenon