Gusev Konstantin, Kurchatov Institute / JINR , Gerda meeting Some technical aspects of testing and adaptation of existing detectors

Gusev Konstantin, Kurchatov Institute / JINR , Gerda meeting Preparation of adaptation consists of: I. Testing of existing enriched detectors; II. Repairing of detector performance in the actual cryostats, if it will be needed; III. Estimation of the risks of crystal repacking procedures and Careful check of all necessary operation with typical non- enriched detectors.

Gusev Konstantin, Kurchatov Institute / JINR , Gerda meeting Detector 1Detector 2Detector 3Detector 4Detector 5 Full mass, kG Depletion voltage, V Bias voltage, V (recommended) FWHM, keV at 1332 keV (specifications) FWHM, keV at full HdMo Set-up Test at February 2005 FWHM, keV at 1332 keV Test at May 2005 Bias voltage, V FWHM, keV at 1332 keV TESTING OF EXISTING DETECTORS

Gusev Konstantin, Kurchatov Institute / JINR , Gerda meeting TESTING OF EXISTING DETECTORS For best realization we need: 1.Spectrometric channel with the best performance; 1.Precision pulse generator; 2.Model of PA first stage.

Gusev Konstantin, Kurchatov Institute / JINR , Gerda meeting REPAIRING OF DETECTOR PERFORMANCE For heat and pump procedures we must have: 1.Turbo molecular pump with enough efficiency; 2.Nitrogen traps for elimination of any contaminations of detector; 3.Valve for connecting between pump and detector cryostat; 4.Absolutely clear or new vacuum elements (rings, fillers, etc.); 5.Heater, maybe electric fan (temperature not higher than 150°C).

Gusev Konstantin, Kurchatov Institute / JINR , Gerda meeting POSSIBLE RISKS  Contamination of detector surface because of too early opening of cryostat.  Damage of implantation layer due to careless dismounting of diode from existing support or packing it into the new holder.  Damage of crystal because of too strong pressure in the new support.  Damage of crystal due to thermal shock.  Damage because of keeping and transportation of naked diodes in non- adequate conditions.  Deterioration of lithium layer after too long staying of detectors at room temperature.

Gusev Konstantin, Kurchatov Institute / JINR , Gerda meeting Conclusions I. Testing of all existing detectors. II. Repairing of detector performance inside the actual cryostats. Required time for I and II is about one month at best. III. For elimination of estimated risks when we open cryostats: Special tools for accurate repacking must be ready; Leak proof box for crystals keeping must be ready too ; All adaptation procedures at non-enriched detectors must be realized.