Fabrication of ultra-low radioactivity detector holders for Edelweiss-II

In its first stage, the EDELWEISS-II dark matter experiment will use 21×320g ionization-heat bolometers with NTD thermal sensors. To improve the present sensitivity of EDELWEISS to WIMP interactions by a further factor 100, ultra-low radioactivity detector holders exclusively made of copper and Teflon have been designed. The new design is using the relative expansion coefficients of copper, Teflon and germanium to hopefully ensure a dissipation-free detector holding.