Abstract: An improved X-ray and gamma ray sensitive Vidicon tube having a photoconductor deposited substrate cooled by means of an internal thermoelectric coolers and a heat sink. The cooled photoconductor has a higher resistivity and lower conductivity and hence the device exhibits less dark current.

Abstract: A Charge-Coupled Device is operable as an exposuremeter during the normal exposure of the parallel register by switching one of the parallel register gates temporarily back and forth between drive circuitry and a sense amplifier. During the exposure of the CCD to photons, the gate potentials are set so that photonic generated charge is stored under one or more phases. An arbitrary gate in the parallel register, designated the sense gate, is disconnected from a normal gate driver and connected to a high input impedance amplifier. The potential on a gate adjacent to the sense gate is changed so that charge is transferred under the sense gate and back again thus producing a voltage transient which is proportional to the total transferred charge.