Charge preamplifier for hole collecting PIN diode and integrated tetrode N-JFET

On-chip electronics fabricated on 6 K Omega cm high resistivity wafer is fully characterized and spectroscopic measurements carried out. A new charge sensitive circuit is introduced to amplify the hole signals with on-chip n-channel JFETs and without any resetting devices. The JFET gate-source junction is forward biased and the drain current is stabilized by a low frequency feedback on the JFET p+ well contact (used as a buried gate for the JFET). Preliminary setups with PIN diodes and tetrode n-JFETs are successfully tested. With about 5 pF total input capacitance, resolution of 86 rms electrons at 223K with 10 mu s shaping time is obtained. With about 3 pF, 60 rms electrons at 298 X with 10 mu s are obtained.