In this paper we report the experimental study of high-pressure xenon used as a scintillator, in the context of developing a gamma ray detector. We measure a light yield near 2 photoelectrons per keV for xenon at 40 bar. Together with the light yield, we also measured an energy resolution of ∼9% (FWHM) at 662 keV, dominated by the statistical fluctuations in the number of photoelectrons.

Ultracold neutrons were stored in a volume, using a magnetic dipole field shutter. Radial confinement was provided by material walls. Low-field seeking neutrons were axially confined above the magnetic field. High-field seeking neutrons are trapped inside the magnetic field. They can systematically shift the measured neutron lifetime to lower values in experiments with magnetic confinement

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In this study we report on the scintillation response of Xe gas under irradiation of gamma-rays in the energy range between 50 keV and 1.5 MeV. Xe gas was pressurized to 50 bar and tested as a detector for gamma spectroscopy. The gas was confined in a titanium vessel of 200 mm length and 101 mm diameter with 2.5 mm thick walls. The vessel was sealed with two 3 inch diameter UV transparent windows. The inner surface of the vessel was covered with a reflecting wavelength shifter. Two photomultipliers coupled to both windows at the end of the vessel allowed for registration of 3700 photoelectrons/MeV, which resulted in 7.0% energy resolution registered for 662 keV γ-rays from a 137Cs source. The non-proportionality of the photoelectron yield and intrinsic resolution was studied with gamma photoabsorption peaks. Due to the thickness of the detector vessel, the response of the Xe gas as a scintillator in the low energy range was performed by means of a Compton Coincidence Technique and compared with the gamma absorption results. The shape of the non-proportionality characteristics of Xe gaseous scintillator was compared to the results obtained for NaI:Tl, LaBr3:Ce and LYSO:Ce. A correlation between non-proportionality and intrinsic resolution of Xe gaseous scintillator was pointed out.

Xe sealed under pressure of 50 bar inside a titanium cylinder closed with glass windows was tested as a scintillator for γ-ray detection. Taking advantage of Xe high atomic number of 54, high pressure Xe was used for γ-ray spectrometry in the range between 50 keV and 1.5 MeV. Compton electron response was also measured down to 7 keV by means of a Compton coincidence technique. The non-proportionality curve of the Xe scintillator turned out to be of similar shape to the one characteristic for doped alkali iodide crystals. Along the nonproportionality studies, energy resolution at a wide energy range was also measured. The Xe gas detector showed an energy resolution of 7.0% at 662 keV γ-rays, with a photoelectron yield of 3700 phe/MeV.