Halliburton Company

Allen Nunley

Darrell S Sonne

John G Kampfer

For use in a sonde adapted to be lowered in a well bore, the present apparatus sets forth an improved nuclear event detector. The detector is sized and shaped monotonically increasing in cross section or diameter with increasing distance from the radiation source to thereby bias the detector; this bias counteracts the bias arising from geometry altering the pattern in which nuclear events impinge on the detector, thereby altering the distribution of such events.

Graded shaped spatial resolution nuclear detectors

For use in downhole logging tools responsive to gamma rays or x-rays, an improved scintillation device is set forth. In the preferred and illustrated embodiment, a scintillation crystal, typically sodium iodide (thallium activated), is utilized. It is an elongated, regular structure having two ends, and separate photomultiplier tubes (PMT) are attached at the separate ends. The two PMT output signals are supplied to a circuit which forms a signal adjusted or modified to compensate for loss of light energy arising during transmission through the scintillation crystal to the PMT's.

High resolution scintillation crystal

For use in a nuclear well logging tool, detector pulse simulator circuits in the preferred and illustrated embodiments are set forth. The simulator circuit is adapted to be placed in a sonde for connection with a well logging tool to provide simulated detector pulses. It is selectively switched on to the output a calibrated pulse sequence function through a number of different levels. It incorporates a circuit means forming pulses limited in amplitude by an envelope yielding pulses of differing amplitude in progression. The circuit is stepped repetitively through its range of operation, for example, from a minimum voltage peak to some specified maximum and then recycles.

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Houston, TX, United States of America

Allen Nunley