Description
Gamma spectroscopy detects electromagnetic radiation emitted by sources typically activated in the reactor for the purpose of identifying and quantifying isotopes present in samples. This is typically accomplished through the use of specially fabricated semiconductors, in our case high purity germanium. As gamma radiation enters the detector’s volume, it creates ion pairs, which are quickly collected by a biasing voltage. That small amount of current is then amplified and sorted according to magnitude using rapid electronics. The resulting data is then analyzed by comparison to known standards to identify energy and isotope, as well as the content in the actual sample.
Systems
HPGe System 30% Stainless Steel Cap with Automated Sample Changer
The primary detector in the facility, this 30% HPGe is housed in a large iron shield in order to reduce the amount of background radiation incident on the detector. This unit is always kept ready for use and is typically in use for longer counting experiments. In the last few years, an automated sample changer capable of processing jobs of up to 200 samples has been in development and is nearing completion.
HPGe System 60% Stainless Steel Cap with Compton Suppression
A large detector equipped with a small, portable type dewar (nitrogen reserve) is located in the reactor room and ready for use upon request. The higher efficiency (relative to a standard sodium iodide detector) is a result of the larger germanium crystal which composes the detector. This allows for more sensitive detection of low levels of radiation from samples. An optional bismuth germanate (BGO) annulus can be activated to provide a moderate amount of Compton suppression for this system.
HPGe System 30% Carbon Fiber Window with Compton Suppression
Located in an ultra low background counting room composed of pre-World War II steel construction, this gamma spectroscopy system achieves the lowest minimum detectable amounts of radioactivity of any of our systems. It was recently purchased in 2012 through a grant from the Nuclear Science and Security Consortium and manufactured by Canberra (now Mirion).
