Study of ruggedness of YAP(Ce) scintillator used in gamma ray detectors for oilfield

Schlumberger produces gamma ray detectors for use in its oil exploration tools. The detectors are based on rugged ceramic photomultiplier tubes (PMTs), produced in house, and various scintillators. For oilfield applications, gamma ray detectors require reliable and stable performance during hundreds of hours of operation in harsh well-logging environment with sustained high shock levels and hot temperatures. Therefore, the scintillator materials must withstand high mechanical and temperature shock. In some environments, the temperature ramp rates can reach as high as 40 C/minute, which could create enough stress to break scintillator materials and their packaging. The mechanical shock levels exceed 100g. The most commonly used scintillator in oilfield nuclear tools is NaI(Tl), in a special shock-proof hermetic packaging, whereas newer Schlumberger tools use LaBr3(Ce) and YAP(Ce) scintillators. We have evaluated ruggedness of a YAP (Yttrium Aluminum Perovskite) scintillator in comparison to the more known behavior of NaI(Tl) and LaBr3(Ce).