High sensitivity operation of discrete solid state detectors at 4 K

Techniques are described to allow operation of discrete solid state detectors at 4 K with optimized junction field effect transistor (JFET) amplifiers. Three detector types cover the 0.6–4-μm spectral range with a noise equivalent power (NEP) of ~10^−16 Hz^−1/2 for two of the types and potential improvement to this performance for the third. Lower NEPs can be anticipated at longer IR wavelengths.