140 TBq Cobalt-60 source Eldorado collimator

The ARPANSA teletherapy unit is a 140 TBq Cobalt-60 source in an Eldorado collimator. The source is used to provide Cobalt-60 calibrations for thimble chambers used in radiotherapy. The majority of radiotherapy treatments in Australia use dosimetry measurements traceable to a calibration on this source.

Farmer chamber in a water phantom undergoing calibration in front of the Eldorado Cobalt-60 teletherapy source

The source can provide continuous absorbed dose to water rates of between 1 and 10 mGy/s at 1 m. As well as chamber calibrations, the source is used to deliver known doses to dosimeters for quality assurance and research purposes.