Gamma scanner conceptual design report

The Fuels and Materials Examination Facility (FMEF) will include several stations for the nondestructive examination of irradiated fuels. One of these stations will be the gamma scanner which will be employed to detect gamma radiation from the irradiated fuel pins. The conceptual design of the gamma scan station is described. The gamma scanner will use a Standard Exam Stage (SES) as a positioner and transport mechanism for the fuel pins which it will obtain from a magazine. A pin guide mechanism mounted on the face of the collimator will assure that the fuel pins remain in front of the collimator during scanning. The collimator has remotely adjustable tungsten slits and can be manually rotated to align the slit at various angles. A shielded detector cart located in the operating corridor holds an intrinsic germanium detector and associated sodium-iodide anticoincidence detector. The electronics associated with the counting system consist of standard NIM modules to process the detector signals and a stand-alone multichannel analyzer (MCA) for counting data accumulation. Data from the MCA are bussed to the station computer for analysis and storage on magnetic tape. The station computer controls the collimator, the MCA, a source positioner and the SES through CAMAC-based interface hardware. Most of the electronic hardware is commercially available but some interfaces will require development. Conceptual drawings are included for mechanical hardware that must be designed and fabricated