Stability of High-Pressure Xenon Gamma-Ray Spectrometers

ABSTRACT The stability of high-pressure xenon gamma-ray spectrometers has been measured at Mirmar Sensor. Stability was measured by tracking the 137 Cs peak of the entire spectroscopy system including detector, preamplifier, amplifier, and multi-channel analyzer over time in a laboratory setting. Overall system gain drift is about 0.016%. Resolution drifts are about 0.15%. The overall system energy resolution is between 1.7 and 1.8% at 662 keV. Keywords: gamma-ray, X-ray, spectrometer, detector, xenon 1. INTRODUCTION The search for better resolution on gamma-ray spectrometers has been ongoing for many years. Much of this work has been focused on the room temperature semi-conductor materials such as CdTe, CdZnTe and HgI 21 . Also for many years there has been work on high-pressure xenon detectors, mainly in Russia 2,3,4,5,6 . The resolution regime of about 2% satisfies many spectroscopy needs in environmental protection, non-proliferation and homeland security. Xenon spectrometers fill the niche between scintillators such as NaI and HPGe. This relationship is illustrated in Figure 1. Xenon has with about 2% resolution and has an active mass between 50 grams and several kilograms. The resolution of xenon spectrometers is not far different than the room temperature semi-conductors, but xenon detectors are generally larger.