PopTop Capsule*

The innovative PopTop capsule is the core of the instrument. Its sealed and self-pumping cryogenic enclosure contains the detector element and the front end of the preamplifier, consisting of a cooled FET and resistor (resistive feedback) or junction transistor (transistor-reset active feedback). The rest of the preamplifier and a HV filter, electrically connected by vacuum feedthroughs, are also part of the capsule.

*U.S.A. Patent No. 4,851,684