CRYOGENIC VOLTAGE-SENSITIVE PREAMPLIFIER USING GAAS-MESFETS OF LOW 1/F NOISE

A voltage-sensitive preamplifier using GaAs MESFETs of low 1 f{hook} noise has been developed. The voltage gain is fixed to 51. With a total power dissipation of 54 mW the preamplifier's series noise level at 4 K is 9 nV/Hz 1 2 at 100 Hz and 0.3 nV/Hz 1 2 at 100 kHz. The input bias current of the preamplifier was determined to be lower than 10 fA below 100 K. Response to a step pulse gave a rise time of 40 ns when loaded with a 130 pF load. The voltage-sensitive preamplifier is presently used in Milano for signal readout and characterization of large-mass bolometric particle detectors. An energy resolution of 13 keV for the 1330 keV of a 60Co gamma source was obtained with an 11 g Ge bolometric detector readout with this preamplifier. © 1990.