Performance results for scintillation detectors for high temperature environments including MWD

Sheet reflectors and elastomeric potting materials have become available for packaging NaI(Tl) scintillation detectors. The problem of compatibility of these materials with NaI(Tl) in the high-temperature encountered in oil well applications is discussed. Specially treated systems that are compatible with NaI(Tl) to at least 200 degrees C are described. Their performance is as good as that of traditional packed-powder systems, with only a 5 to 10% pulse height drop during initial exposure to 180 degrees C. Additional data to 200 degrees C show similar stable results, indicating potential application in the harsh MWD (measurement-while-drilling) environment.<
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