Gaseous Detector Laboratory

Portable Gamma-Ray Spectrometer, Using Compressed Xenon

An ionization chamber using compressed xenon has been designed and built for gamma-ray spectrometry. The device is based on signal measurement from a parallel plate detector, with the gas enclosure constructed specifically for packaging into a portable instrument. It comprises two small containers that can be setup for operation in just a few minutes. Its sensitivity is 100 keV to over 1 MeV, with a resolution at 662 keV of 2.5% FWHM for uniform irradiation, and 2% FWHM for collimated irradiation, comparable to the best ever with compressed xenon. It also exhibits greater specificity than most scintillators, such as NaI. The device is insensitive to neutron damage and has a low power requirement.

A photo of the internal components of the ionization chamber:

A pulse height spectrum from the compressed xenon spectrometer:

Reference:

Graham C. Smith, George J. Mahler, Bo Yu, Walter R. Kane, and John K. Markey; Gamma Ray Spectrometer Utilizing Xenon at High Pressure; BNL 49994; pres. 35th Annual Mtg. of Inst. for Nuclear Materials Management, Naples, FL, 17-20 July (1994); Proc. 35th Annual Mtg. of Inst. for Nuclear Materials Management, 783-788 (IMM Press, Northbrook, IL) (1995).

G. J. Mahler, B. Yu, G. C. Smith, W. R. Kane, and J. R. Lemley,"A Portable Gamma-Ray Spectrometer for Using Compressed Xenon," IEEE Trans. Nucl. Sci. NS-45 (1998) 1029-1033.