Ortec, Inc.

Eg&g Instruments, Inc.

Thomas W Raudorf

Dale A Gedcke

Pat Sangsingkeow

Mario Pierangelo Martini

Michael Leon Simpson

A three-axis radiation detection system whose inner and outer electrodes are shaped and positioned so that the shortest path between any point on the inner electrode and the outer electrode is a different length whereby the rise time of a pulse derived from a detected radiation event can uniquely define the azimuthal and radial position of that event, and the outer electrode is divided into a plurality of segments in the longitudinal axial direction for locating the axial location of a radiation detection event occurring in the diode.

Three-axis asymmetric radiation detector system

An radiation detection system whose inner and outer electrodes are shaped and positioned so that each path between them is a different length is a different length whereby the rise time of a pulse derived from a detected radiation event can uniquely define the azimuthal and radial position of that event.

Asymmetric radiation detector system

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.

Charge trapping correction in photon detector systems

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. Thus, when a reverse bias is applied across the germanium crystal between the contacts, the resulting equipotential lines are relatively crowded at the groove, the electric field is of reduced strength adjacent the open end of the thin contact, and reverse leakage current is inhibited.

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Oak Ridge, TN, United States of America

Thomas W Raudorf