LUX-ZEPLIN

Abstract:

We have constructed an instrument, CryoEDM, to measure the neutron electric dipole moment to a precision of 10-28 e cm at the Institut Laue-Langevin. The main characteristic is that it is operating entirely in a cryogenic environment, at temperatures of 0.7 K within superfluid helium. Ultracold neutrons are produced in a superthermal source and stored within the superfluid in a storage cell which is held in a magnetic and electric field. NMR measurements are carried out to look for any shifts in the neutron Larmor precession frequency associated with the electric field and the neutrons are detected in-situ in the superfluid. Low temperature SQUID magnetometry is used to monitor the magnetic field. We report on the current status of the project that is now being commissioned and give an outlook on the future exploitation of the instrument. © 2010 IOP Publishing Ltd.

Abstract:

The CRESST experiment monitors 300 g CaWO4 crystals as targets for particle interactions in an ultra low background environment. In this paper, we analyze the background spectra that are recorded by three detectors over many weeks of data taking. Understanding these spectra is mandatory if one wants to further reduce the background level, and allows us to cross-check the calibration of the detectors. We identify a variety of sources, such as intrinsic contaminations due to primordial radioisotopes and cosmogenic activation of the target material. In particular, we detect a 3.6 keV X-ray line from the decay of ⁴¹Ca with an activity of (26 ± 4) μ Bq, corresponding to a ratio ⁴¹ Ca / ⁴⁰ Ca = (2.2 ± 0.3) × 10^{- 16}. © 2009 Elsevier B.V. All rights reserved.

Abstract:

Oxide crystal scintillators play a considerable role in fundamental and applied researches. However, working out of new generation of high-sensitivity equipment and new methods of research puts higher requirements. The ZnBO 4 (B = W, Mo) crystals were grown from charge in platinum crucibles with high frequency heating, using the Czochraiski method. The raw powder with optimum composition was prepared by solid phase high temperature synthesis using ZnO and BO3 (B = W,Mo) with 4-5N purity. Single crystals with sizes up to ∅ 50× 100 mm were grown and scintillation elements of various sizes and shapes (cylinders, rectangular and hexahedron prisms) were produced. High spectrometric characteristics were obtained for ZnWO4:R = 8-10% under excitation by ¹³⁷Cs [Eγ= 662 keV), low radiation background (less than 0.2 mBq/kg) and low afterglow (0.002%, 20 ms after excitation). The obtained results demonstrate good prospects for ZnWO 4 and ZnM0O4 crystal scintillators for application in low-count rate experiments, searching for double beta decay processes, interaction with dark matter particles, and also studies of rare decay processes. The material has also a, good potential for application in modern tomography, scintillation bolometers and for other major researches using scintillators.

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 - 10 picobarn. A major advantage of EURECA is the planned use of more than just one target material (multi target experiment for WIMP identification). © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.