Saint-gobain Industrial Ceramics, Inc.

Saint-gobain Industrial Cermaics, Inc.

Carlos M Grodsinsky

Kevin Kimmich

William David Sekela

Muhammad Ejaz

Kevin D Kimmich

A scintillation detector includes a scintillation crystal directly coupled to a photomultiplier tube (PMT). The crystal/PMT subassembly is attached to a voltage divider and the entire device is hermetically sealed in a stainless steel outer case. Conductors are passed through the hermetic package from the voltage divider via a high temperature metal to ceramic pass-through. The crystal and PMT are longitudinally loaded within the outer case by springs in order to minimize vibrations in the crystal and PMT. A thermoplastic support sleeve circumscribes the crystal and the PMT to protect the crystal and PMT from excessive longitudinal loading. Preferably, the support sleeve and the crystal have similar coefficients of thermal expansion so that the crystal and the support sleeve experience similar dimensional changes due to temperature fluctuations, allowing the support sleeve to best maintain its stress-limiting function as temperature within the detector changes. The support sleeve also protects the crystal/PMT subassembly from bending loads.

Scintillation detector without optical window

A closed-loop stabilization system and method for a radiation detector system including a scintillator and a light sensing device for detecting the scintillation light produced in the scintillator through interaction with impinging radiation. A spectrally stable gamma ray measurement for downhole and other non-isothermal gamma ray measurement applications is obtained by use of a light source for emitting photons, preferably ultra-violet photons, into the scintillator that are not detectable by the light sensing device. The light source causes the scintillator to fluoresce at a wavelength detectable by the light sensing device, and the change in measured fluorescence is used to adjust system gain to account for variations in scintillator output attributable to environmental conditions. In this manner, the stabilization system adjusts the system gain to maintain consistency among radiation measurements over a wide temperature range.

Radiation detector system and method with stabilized system gain

A well logging instrument and method that remove vibration induced noise from the output of a detector including a scintillation crystal. The invention is based on a realization that pulses induced by vibration during MWD operations are characteristically periodic, whereas pulses generated down hole by gamma rays occur at random intervals and are characteristically non-periodic. The instrument and method involve positioning a scintillation crystal package in the high vibration environment for interaction with incident radiation, using a light sensing device to convert photons received from the scintillation crystal package into an electrical signal which over time is composed of radiation induced events that are non-periodic and vibration induced events that are periodic, distinguishing the periodic events using a time history of the electrical signal, and removing the periodic events from the electrical signal to provide a corrected electrical signal from which vibration induced components have been removed. Also disclosed is a method for using the information gathered for vibration induced events to give an indication of the remaining lifetime of the scintillation crystal.

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Strongsville, OH, United States of America

Carlos M Grodsinsky