veljko radeka : notes on the origin of charge amplifiers j uly2, 2014
DESCRIPTION
Veljko Radeka : Notes on the origin of charge amplifiers J uly2, 2014. The first record of a Charge-Sensitive Amplifier Circuit . Classical “integrator” known from WWII ( 1941-5,) appears as charge amplifier in ~ 1950-ies ( Gatti , et al.):. 1948. C f. C f. - PowerPoint PPT PresentationTRANSCRIPT
Veljko Radeka: Notes on the origin of charge amplifiers
July2, 2014
1
The first record of a Charge-Sensitive Amplifier Circuit
Classical “integrator” known from WWII (1941-5,) appears as charge amplifier in ~1950-ies (Gatti, et al.):
Input capacitance ~ open-loop gain x Cf
1948
Vacuum tube at the input until ~1963 when the first JFET is used …
Cf
Cf
The “last word” from vacuum tubes – introducing Ge detectors (Tavendale,1963)
3
Noise: ~200 e rms at 20pF, 1-2μs
The Cascode!
Feedback
Original charge preamp with JFET, 1968
From: V. Radeka“State of the art of low noise amplifiers for semiconductor radiation detectors”Proc. Intern. Symp. Nuclear electronics, vol. I (1968), p. 46.1, 28