Samuel Henry

Abstract:

In the CRESST-II experiment, scintillating CaWO4 crystals are used as absorbers for direct weakly interacting massive particles (WIMP) detection. Nuclear recoils can be discriminated against electron recoils by measuring phonons and scintillation light simultaneously. The absorber crystal and the silicon light detector are read out by tungsten superconducting phase transition thermometers. Results on the sensitivity of the phonon and the light channel, radiopurity, the scintillation properties of CaWO4, and on the WIMP sensitivity are presented. (C) 2003 Elsevier B.V. All rights reserved.

Abstract:

The upgrade of the CRESST experiment to a 10 kg target of phonon/light detectors necessitates the installation of 66 readout channels in the CRESST cryostat. We report on the status of this upgrade and discuss the issues related to the installation of the correspondingly high number of SQUIDs and wires in an ultra-low temperature environment.

Abstract:

We have carried out a series of magnetic field measurements using a portable three-axis SQUID magnetometer at the Laboratoire Souterrain à Bas Bruit (LSBB), Rustrel, France. The magnetometer was originally developed as part of the cryoEDM neutron electric dipole moment experiment [1], where we need to monitor drifts in the magnetic field at a level of ∼0.1 pT. The cryoEDM SQUID system is a 12-channel magnetometer designed to operate in a large cryostat with extensive magnetic shielding [3]. We have tested smaller prototype systems during a series of trips to LSBB [2], primarily to test the SQUIDs, and control and DAQ electronics in a low noise environment. However this investigation also provided an opportunity to characterise the magnetic environment at different locations within the LSBB complex. We monitored the magnetic field at various positions inside the underground laboratory, including the Capsule, the Galerie Anti-Souffe (GAS) and the Galerie Gaz-Brûlés (GGB). We recorded several hours of data at each location to compare with that recorded at the same time by the LSBB [SQUID]2 system permanently installed in the Capsule, and from this we have characterised the relative amplitudes of magnetic field fluctuations in the different locations. SQUID resets are corrected using software, but as this process is not perfect an accurate comparison can only be done during stable periods. Software development and data analysis are still in progress. Preliminary analysis suggests the magnetic field measured in the Capsule is approximately 75% that measured in the GAS and GGB.

Abstract:

CryoEDM is an experiment that aims to measure the electric dipole moment (EDM) of the neutron to a precision of 10^−28 e cm. A description of CryoEDM, the apparatus, technologies and commissioning is presented.