TRIUMF, like all facilities in Canada in which the staff are exposed to ionising radiation , is required by law to provide an adequate program for measuring and recording the cumulative radiation dose any person receives at work. The dosimetry service we use is provided by the Canadian Bureau of Radiation and Medical Devices (BRMD) and the dosimeters used are thermoluminescence dosimeters (TLDs) . The dosimeters of most TRIUMF workers are sent to the BRMD, in Ottawa, for reading four times a year. The dosimeters of those workers whose duties lead to exposures near the TRIUMF administrative limit are read once a month. A permanent record of the individual doses is kept by the BRMD in the National Dose Register , and a copy is sent to TRIUMF.