Abstract: In an energy spectroscopy system in which the photon detector such as a germanium detector provides pulses indicative of incident gamma or x-ray radiation, compensation circuitry corrects the amplified pulse output for charge trapping effects in the detector. The compensated output is provided to a prior art multichannel analyzer. The compensation circuit adds to the detected pulse a correction factor proportional to a polynomial function of charge collection time of the carrier being trapped multiplied by the amplitude of the pulse. In this manner, the output pulse is increased to compensate for impediments to charged carrier migration within the structure of the detector, and resolution is improved.

Abstract: An automatic pole-zero adjustment circuit is provided for an ionizing radiation spectroscopy system which comprises a pole-zero network circuit, coupled to the system and having an electrical chracteristic which varies as a function of an input control signal, for permitting pole-zero adjustment of the system; a sampling circuit coupled to the system, for sampling a segment of the trailing edge of random pulses passing through the system; and a control signal circuit coupled to the sampling circuit, for generating the input control signal as a function of the sampling to permit cancellation by the pole-zero network circuit of undershoot in the system. The pole-zero network circuit may include a real pole in the signal path of the network circuit set coincident with the real pole of a high pass filter in the system itself. The control signal provided to the pole-zero network circuit is digitized.

Abstract: In a photon detector system, such as a cryogenic gamma radiation detector cooled by a dewar, a vacuum-jacketed radiation detector is provided in a cryostat assembly. The detector can be used with any one of a plurality of cryostats without breaking the vacuum seal therearound when transferring from one cryostat or dewar to another. The detector is vacuum-jacketed and mechanically and thermally connected to an axially projecting conducting member, which member is received in a thermally conducting transition member contained in the cryostat. The transition member is thermally and mechanically coupled to the dewar and may include a fluid path completing a vacuum jacket in the dewar.

Abstract: A radiation detector made of hyperpure germanium has generally the shape of a hollow cylinder with an outer generally cylindrical surface and an inner generally cylindrical surface and is formed with a p.sup.+ contact and n.sup.+ contact. One of the contacts is on the outer cylindrical surface of the semiconductor and the other is on the inner cylindrical surface, and both contacts are themselves cylindrical. Each cylinder formed by a contact is open at at least one end thereof, the open ends being adjacent rather than opposite ends of the respective cylinders. One of the contacts is a thin contact, having a thickness of one micron or less. The germanium crystal is formed with an annular groove coaxial with the contacts and extending to within one millimeter of the thin contact at a position inward of the open end of the thin contact.

Abstract: A trigger pulse, derived for instance from a radiation detector, is applied to an input circuit which splits the pulse into two components. The respective component signals are acted on by two characteristic circuits, one of which attenuates the first signal component and the other of which delays the second signal component. The respective attenuated signal and delayed signal are applied to a passive element, such as a differential transformer to invert one component with respect to the other and to sum the resulting signals. The output signal of the differential transformer is a constant-fraction bipolar timing signal which is accurately correlated with the time of occurrence of the event identified with the trigger pulse.

Abstract: The invention provides a method and apparatus for determining the concentration of an element such as a heavy metal in a matrix of a material such as rock by the X-ray or gamma-ray fluorescence technique.It allows the use of this technique where a sample to be analyzed has a rough or jagged surface. The effect of the rough surface is eliminated by adjusting the distance between the source and/or detector from the sample so that the rate of detection of radiation in a reference energy band is maintained constant for all samples, including reference samples used for calibration. The reference band is at least partly outside the band or bands characteristic of the element sought.

Abstract: In the digital intervalometer disclosed herein, a vernier measurement providing a resolution finer than one clock period is obtained by charging a single capacitor both during the interval between a start signal and a subsequent clock pulse and also during the interval between a clock pulse subsequent to a stop signal and a delayed stop signal. The analog voltage to which the capacitor is charged is converted to a digital value, which digital value is then combined with a clock count accumulated between the stop and start signals to provide a combined digital measurement having a resolution substantially finer than one clock period.