Experiences with the Norwegian research reactor JEEP II in neutron transmutation doping

The Norwegian research reactor JEEP II, situated at Kjeller, has been in use for neutron doping of silicon since 1975. Ordinary radionuclide production irradiation facilities are used, with some modifications of the loading equipment. The neutron flux range for this type of irradiation is 0.5-1.4 x 1013 n/cm3, and the maximum diameter of silicon ingots that can be handled is 78 mm. The available effective volume for silicon irradiation is about 32 litres. For neutron flux variations within + or - 5%, this volume is reduced to about 13 litres, corresponding to a silicon charge of 30 kg. The reactor must be shut down to permit insertion and removal of the silicon charge. However, a practical system has been developed to make the best utilization of the reactor facility for its intended purpose