An active personal dosimetry system based on a smart, low power, Si diode badge

A low cost active personal dosimeter badge based on a p-n junction Si diode detector, developed earlier, has been upgraded into a smart micro-controller (Microchip PIC 16F627) based badge. The new smart design has a number of advanced features like infra-red, non-contact PC link, storage of user ID and calibration parameters in a built- in EEPROM through a PC, 3V operating voltage, preset dose alarm, half-hourly storage of cumulative dose, controlled dosimeter switch off with storage of cumulative dose data at the time of switch off, etc. The system includes a stand-alone reader with a local LCD display and a low speed USB interface to a PC. A PC-resident, user-friendly software written in VC++ is used for setting the alarm level and user ID and for downloading the dose data from the badge. The half-hourly readings are displayed in a bar chart format for analysis in case of a high dose incident. A built-in low power piezo buzzer in the badge gives an alarm if cumulative dose exceeds the set limit. The paper discusses the hardware and software details of the system in detail. (author)