LUX-ZEPLIN

Abstract:

The scintillation properties of a zinc tungstate crystal, shaped as a hexagonal prism (height 40 mm, diagonal 40 mm) were determined. An energy resolution of 10.7% for the 662 keV γ-line of 137Cs was measured with the scintillator placed in a light collection setup similar to that used by the CRESST dark matter search. The light output and decay kinetics of ZnWO4 were examined over the temperature range 7-300 K and confirmed to be competitive with those of CaWO4. The radioactive contaminations of the ZnWO4 scintillator measured in the Solotvina Underground Laboratory do not exceed 0.1-10 mBq/kg (depending on radionuclide). Our study highlights the excellent feasibility of this ZnWO4 scintillator for a cryogenic dark matter experiment. © 2008 Elsevier B.V. All rights reserved.

Abstract:

The luminescence properties of K3Tb(PO4)2 activated by Eu3+ were studied at excitation over the 120-300 nm wavelength range. It is demonstrated that Tb3+ ions, exhibiting a strong absorption band in the vacuum-ultraviolet (VUV), can provide efficient sensitisation of Eu3+ emission in this wave length range, giving rise to intense red luminescence at 150 nm excitation. A proof is given for the concept of VUV sensitisation enabling the engineering of luminescence materials with enhanced conversion efficiency of VUV radiation into visible light. © 2009 WILEY-VCH Verlag GmbH&Co. KGaA, Weinheim.

Abstract:

EURECA (European Underground Rare Event Calorimeter Array) is an astro-particle physics facility aiming to directly detect galactic dark matter. The Laboratoire Souterrain de Modane has been selected as host laboratory. The EURECA collaboration unites CRESST, EDELWEISS and the Spanish-French experiment ROSEBUD, thus concentrating and focussing effort on cryogenic detector research in Europe into a single facility. EURECA will use a target mass of up to one ton, enough to explore WIMP - nucleon scalar scattering cross sections in the region of 10-9 - 10-10 picobarn. A major advantage of EURECA is the planned use of more than just one target material (multi target experiment for WIMP identification). © EAS, EDP Sciences 2009.

Abstract:

The CRESST II experiment is a dark matter search using cryogenic phonon-scintillation detectors, aiming to detect WIMP dark matter particle interactions. The detector consists of individual, modular and scintillating (CaWO4or ZnWO4) target crystals, each equipped with a phonon sensor for precise determination of the energy deposited in the crystals. Each module is further equipped with a separate cryogenic scintillation light detector, allowing event-by-event background discrimination. An extended commissioning run during 2007 has set an upper limit on theWIMP-nucleon scattering cross section. Attention is currently focussed on the interpretation of a few remaining nuclear recoils candidate events.

Abstract:

One of the most intriguing open questions in modern particle physics is the nature of the dark matter in our universe. As hypothetical weakly interacting massive particles (WIMPs) do interact with ordinary matter extremely rarely, their observation requires a very low-background detector environment regarding radioactivity as well as an advanced detector technique that allows for active discrimination of the still present radioactive contaminations. The CRESST experiment uses detectors operating at milli-Kelvin temperature. Energy deposition in the detectors is recorded via the simultaneous measurement of a phonon-mediated signal and scintillation emitted by the CaWO(4) crystal targets. The entire setup is made of carefully selected materials. In this note we report on the development of ultra-pure bronze (CuSn(6)) wire in small quantities for springs and clamps that are currently being used in the CRESST II setup.