USE OF BUBBLE DETECTORS TO MEASURE NEUTRON CONTAMINATION OF A MEDICALACCELERATOR PHOTON-BEAM

Medical electron accelerators generate spurious neutron radiations: in order to protect patients, neutron radiation levels must remain below internationally recommended values. In the present study, bubble dete ctors were used to measure the neutron component in the primary beam a nd outside the radiation field for 8,15, 18 and 25 MV photons from a S aturne 43F type medical accelerator. The results are compared with tho se obtained using other methods. Values of between 0.25 and 7.5 mSv.Gy (-1) were determined at the beam isocentre for photons of 8 to 25 MV; these values are in agreement with those published in the literature.