Decay characteristics of the induced radioactivity in the target cave of a medical cyclotron

After the transfer of the thick copper target plate irradiated with 3 meV protons from a medical cyclotron, the gamma dose rate in the target cave was monitored every minute for 25 hours using wall-mounted gamma area monitors. The dose rate decay curve was fitted with four exponential functions. By analysing the slope of the exponentials the traces of radioactive 28Al, 56Mn 24Na and 59Fe were identified. The results were used to minimize personnel radiation exposure during maintenance work on the cyclotron.