Development of an automated shielded chair whole-body monitor

A standard shielded chair whole-body monitor has been developed as a computer controlled, unattended, walk-in-type of whole-body monitor for internal dosimetry of radiation workers. A radiation worker enters his personal computer code through the attached computer terminal and follows a few instructions on the screen. The chair door then opens automatically and after the worker has positioned himself into the counting geometry in the chair, the door closes. At the end of the whole-body monitoring for a pre-set time, the chair door opens again and the worker moves out. The monitoring data acquired on a 4K-MCA is saved in the computer memory automatically and the chair door closes again making it available for monitoring the next worker. The system also gives audio instructions to the worker to occupy the chair and to move out after the counting is over. A system supervisor can come at any convenient time and get a print out of the monitoring report in the standardised format or carry out any detailed analysis if required. The system has the software for calculating intakes and the committed effective doses using the latest ICRP methodologies, from the measured retained activities of the various important fission and activation products like 137Cs, 131I, 60Co, 125Sb etc. This type of system with trained staff is also expected to be of value in case of emergencies as a quick monitoring system.