Protean utilizes a dual phosphor scintillator type detector for applications where portability or gas-free operations are desired. The dual phosphor detector gets its name from the use of ZnS(Ag) that is adhered to a thin disk of plastic scintillator. These detectors are always supplied with an 80 µg/cm² aluminum window. This assembly is coupled to a photomultiplier tube and then encased in a light tight enclosure. All that is required to acquire counts is applied voltage. No gas is required.
The dual phosphor detectors provide excellent alpha-beta efficiency, albeit not at the same performance level of the gas flow detectors. Their portable, gas-free use; however, has made them a popular detector type for performing alpha/beta type measurements. These detectors are currently employed in Protean's ASC-950-DP and MPC-900-DP.