Skin dose measurement with microspec-2TM

For many years, Los Alamos National Laboratory has used Eberline HP-260 beta detectors to measure skin dose. However, this detector has a limitation in that it does not measure the beta spectrum, and skin dose can be determined only if the contaminating radioactive isotope is known. A new product, MICROSPEC-2, has been developed, which contains a small, portable computer with a multichannel analyzer and a beta probe consisting of a phoswich detector. The new system measures the beta spectrum and automatically folds in the beta fluence-to-dose conversion function to yield skin dose. The measured spectra are in good agreement with theoretical curves for different kinds of beta sources and for beta energies down to about 200 keV. The spectroscopic method allows the derivation of skin doses with more reliable accuracy than the normal integrated dose method.