Performance of a chamber for studying the liquid xenon response to /spl gamma/-rays and nuclear recoils

Abstract

-The design and performance of a 1.2 liter liquid xenon chamber equipped with 7 two-inch photomultiplier tubes, with the purpose of studying the scintillation response of xenon to γ-rays and neutrons, is described. Measurements with γ-rays indicate a high VUV light collection efficiency resulting in ~5.5 photoelectrons per 1 keV of deposited energy. The energy resolution (FWHM) is 18% and 22%, for 122 keV and 511 keV γ-rays, respectively. An algorithm for the reconstruction of the scintillation coordinates in (x,y) plane was developed and tested. The position resolution is estimated to be σ=6.9 mm for 122 keV γ-rays.

Scintillation efficiency of liquid xenon for nuclear recoils with the energy down to 5keV

“…The photomultipliers were periodically calibrated between runs, in situ, at the operating conditions with a pulsed light emission diode [6]. To obtain the scintillation efficiency for nuclear recoils we first determined the most probable value of the amplitude distribution of the signals from the elastic scattering.…”

“…More details on the design of the chamber, its operation and xenon purification are reported in [6].…”

“…The chamber has been thoroughly tested with a gamma-ray source as reported in [6]. These bench tests show a high light collection efficiency, yielding in average To detect neutrons that scatter in the liquid xenon chamber we used a NE213…”

“…The front-end electronics and the data acquisition system are described elsewhere [6]. The data acquisition was triggered by the PMT signals from the liquid xenon chamber, if two or more PMTs showed a signal above the threshold set at ≈ 1 photoelectron.…”

Liquid noble gas detectors for low energy particle physics

“…Importantly, it is found that the reflectivity of a PTFE surface in contact with liquid xenon is enhanced quite significantly relative to that in vacuum (see Figure 16, left). Values in excess of 90-95% have been reported for the PTFE/LXe interface [168,169,170].…”