Title :
Low-noise low-mass front end electronics for low-background physics experiments using germanium detectors
Author :
Barton, Paul ; Luke, Paul ; Amman, Mark ; Chan, Yuen-Dat ; Detwiler, Jason ; Loach, James ; Martin, Ryan ; Poon, Alan ; Tindall, Craig ; Vetter, Kai
Author_Institution :
Lawrence Berkeley Nat. Lab., Berkeley, CA, USA
Abstract :
A low-noise resistive-feedback front-end electronics assembly has been developed for use with p-type point contact (PPC) Ge detectors in low background experiments. The front end was designed to have a low mass and potentially low radioactivity. It is fabricated on a fused silica substrate, and consists of a low-noise JFET, a feedback resistor formed from an amorphous Ge thin film, and feedback capacitor based on the stray capacitance between circuit traces. The substrate provides the appropriate thermal impedance to allow the FET to operate at the optimal temperature from self-heating when one side of the substrate is held at liquid nitrogen temperature. A noise level of 85 eV FWHM at 20 us peaking time has been observed in combination with a small PPC detector, the 1/f contribution being as low as 30 eV for the front end alone. This approach of employing ultra-low-mass and low-noise front-end electronics in combination with larger-size PPC detectors can be an enabling technology towards the observation of particles and processes such as neutrino-less double-beta, coherent neutrino scattering or cold dark matter.
Keywords :
capacitors; circuit feedback; germanium radiation detectors; junction gate field effect transistors; nuclear electronics; point contacts; radioactivity; resistors; semiconductor thin films; thin films; amorphous Ge thin film; circuit traces; coherent neutrino scattering; cold dark matter; feedback capacitor; feedback resistor; fused silica substrate; larger-size PPC detectors; liquid nitrogen temperature; low background experiments; low-background physics experiments; low-noise JFET; low-noise resistive-feedback front-end electronics assembly; neutrino-less double-beta; noise level; optimal temperature; p-type point contact Ge detectors; peaking time; small PPC detector; stray capacitance; thermal impedance; ultra-low-mass low-noise front-end electronics; Capacitance; Capacitors; Geometry; Heating; JFETs; Resistors; Voltmeters;
Conference_Titel :
Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2011 IEEE
Conference_Location :
Valencia
Print_ISBN :
978-1-4673-0118-3
DOI :
10.1109/NSSMIC.2011.6154397