Direct dark matter search with CRESST and EURECA

The current status of the direct Dark Matter experiments CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) and the planned EURECA (European Underground Rare Event Calorimeter Array) is presented. Both experiments are aimed at the direct detection of WIMPs (Weakly Interacting Massive Particles), potential candidates for the Dark Matter in the universe. New design developments of the cryogenic detectors operated at mK temperatures are investigated to optimize detector performance and to simplify mass production. Thus, CRESST is also providing a basis for the EURECA project, aimed at a ton of cryogenic detectors with a multi-material target.     

Photoelectron extraction efficiency from cesium iodide photocathodes in a pressurized atmosphere of argon and xenon up to 10 bar

Photoelectron extraction efficiency is a key parameter in gaseous detectors design requiring CsI photocathodes, particularly in pressurized applications for rare event experiments. Within this work we report on our measurements of the photoelectron extraction efficiency from a CsI photocathode into argon and xenon up to 10 atm. It is demonstrated that the photoelectron extraction efficiency is independent from pressure when scaling the electric field accordingly. This measurement provides experimental validation to the Monte Carlo predictions.     

Extracting dark current components and characteristics parameters for InGaAs/InP avalanche photodiodes

The dark current of separate absorption grading charge multiplication (SAGCM) InGaAs/InP avalanche photodiodes has been numerical analyzed. SRH current, TAT current, BBT current and avalanche amplification combined together as the dark current have been extracted by simulation separately. The trend of punch-through voltage and breakdown voltage have been discussed, meanwhile the influence of structure parameters also has been investigated.     

Ice shielding in the large scale GENIUS experiment for double beta decay and dark matter search

We suggest here the use of ice as shielding material in the large scale GENIUS experiment for the ultimate sensitive double beta decay and dark matter search. The idea is to pack a working volume of several tons of liquid nitrogens, which contains the “naked” Ge detectors, inside an ice shielding. Very thin plastic foil would be used in order to prevent leakage of the liquid nitrogen. Due to the excellent advantages of ice shielding (high purity and low cost, self-supporting ability, thermo-isolation and optical properties, safety) this could be another possible way of realization of the GENIUS project. Received: 30 July 1998