Active Sample Anticoincidence Guarded Ge(Li) Spectrometer for Low Level Radionuclide Analysis

The problem of spectral interference in large volume radioactive samples counted in a guarded Ge(Li) spectrometer is attacked by a new approach. By making the sample itself a liquid scintillator detector, and using coincidence and anticoincidence gating, the detrimental effects of self absorption can be eliminated. In addition, this technique (denoted gamma-beta coincidence and gamma-beta anticoincidence spectrum analysis) allows discrimination between modes of decay. The system design, logic, performance, and significance to low level radionuclide analysis is presented.