Accuracy Adjustment for a Neutron Transmutation Doping of Si Ingots

HANARO provides two vertical irradiation holes in the D2O reflector region for a Neutron Transmutation Doping (NTD). One of them has been used for a 5 and 6 inch NTD commercial service since 2003 and 2005 respectively. Excellent irradiation uniformity and high accuracy to a target neutron dose have been achieved from the early works of NTD. However, our expected resistivities have exhibited a slightly lower tendency when compared with the measured results by a semiconductor company. To achieve exact neutron irradiations corresponding to the actually measured resistivities, an old K value, which is a constant representing the relationship between the neutron fluence and target resistivity, was investigated and replaced with a new one by analyzing the measured results so far achieved. This paper describes the effects of changing the K value on the irradiation accuracy