Experiments to study the influences of the environment, external to pyroelectric crystals, on certain measurements to discern the properties of crystals, such as LiTaO3, LiNbO3, and CsNO3, are discussed. During increasing temperature and at appropriate pressures electrons in the vacuum system are accelerated to the −z base of the pyroelectric crystal and are repelled from the +z base of the crystal. The electrons striking the crystal may have sufficient energy to excite x-ray absorption edges of the elements in the crystal and the electrons repelled to a target may have sufficient energy to excite x-ray absorption edges in the elements of the target. During decreasing temperature electrons in the vacuum system are repelled from the −z base whereas the electrons are accelerated to the +z base. The light produced, associated with the pyroelectric effect, appears to come from recombination processes in the gases in the vacuum chamber. The polarization charge produced during the change of temperature of the crystals appears to follow the changing temperature in a reproducible manner.

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In the scintillation spectrometer described, the main detecting crystal of NaI(Tl) is enveloped by a hollow cylinder of NaI(Tl) in anticoincidence with the main crystal. This system completely suppresses the peaks associated with the escape of the two quanta from the annihilation following pair production, and it reduces the Compton background by a factor of 7 for 4.43-Mev gamma rays and by a factor of 5 for those of 6.1 Mev.

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