LUX-ZEPLIN

Abstract:

The CRESST experiment is designed to search for weakly interacting massive particle dark matter with cryogenic detectors. CRESST II will use up to 33 CaWO(4) crystals with a total mass of approximately 10 kg. These many detectors require a readout system based on 66-channel superconducting quantum interference devices (SQUIDs). In this article we report on the development of a modular superconducting connector for the 66-channel SQUID readout circuit. We show that the technique developed reliably produces superconducting contacts.

Abstract:

Scheelite CdMoO4 and wolframite eCdWO(4):MO (0.04-0.4wt%) single crystals were studied using the time-resolved spectroscopy under UV excitation over a temperature range of 1.85-300K. The threshold energies for the creation of free charge carriers were measured using the method of photostimulated luminescence. The decay kinetics of the main emission in CdMoO4 and the molybdenum-related emission in CdWO4:MO was studied and the parameters of the triplet excited states of molybdenum-related oxyanions were calculated. (C) 2007 Elsevier Ltd. All rights reserved.

Abstract:

The development of the multi-photon counting (MPC) technique for the investigation of scintillation properties of materials is presented. The technique is based on the recording and analysis of a sequence of individual photon pulses resulting from a scintillation event. The technique is especially advantageous for the analysis of slow scintillation processes and the investigation of temperature-dependent scintillator proper-Lies. The results on the temperature variation of scintillation characteristics of ZnSe and ZnSe-Te are presented to illustrate the performance of the MPC technique. (c) 2007 Elsevier Ltd. All rights reserved.

Abstract:

The future application of ZnWO 4 scintillator in a cryogenic search for rare events is the motivation for optimization of this material. We present results on the effect of Ca doping on the structure and scintillation properties of ZnWO 4. X-ray diffraction analysis revealed that there is no mixing in the CaWO 4-ZnWO 4 pseudobinary system due to a significant mismatch of the crystal structures of CaWO 4 and ZnWO 4. The lattice parameters of Ca-doped ZnWO 4 samples obtained from X-ray powder diffraction data confirmed this finding. It is also shown that ZnWO 4 retains the monoclinic wolframite structure when cooling, at 12 K exhibiting the following lattice parameters: a = 4.6826(2) Å, b = 5.7088(2) Å, c = 4.9230(2) Å and β = 90.541(2)°. The scintillation light yield of the Zn 1-x,Ca xWO 4 was measured using the multi-photon counting technique and it is found that small concentrations of Ca (x = 0.001 - 0.02) cause no deterioration of this parameter. Ca doping of ZnWO 4 is expected to facilitate production of a single-crystalline scintillator. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.