Dosimetric response evaluation of tooth enamel for accelerator-based neutron radiation

To study the neutron response of human tooth enamel, a number of experiments with an accelerator-based neutron source have been designed. The neutron beam was produced with the low gamma yield, 7 Li (p,n) 7 Be type thick target, using the 3 MV McMaster K.N. Van de Graaff accelerator. The dosimetry was done using a pre-calibrated snoopy type neutron dosimeter. Neutron irradiation induces a dosimetric signal in the tooth enamel at the same defect site as gamma produced damage with the same g -values ( g || =1.9973, width 0.4 mT g ⊥ =2.002 , width 0.3 mT ). The dosimetric signal grows linearly with neutron dose from 6– 35 Gy tissue dose. Dosimetric response in two different grain sizes (300– 500 μm , and grains mm ) has shown increased dosimetric amplitude in the larger grains. Dose build up effect on tooth inside the mouth due to cheek was simulated by placing a 4 mm thick paraffin wax layer between the beam and tooth, but had little effect. These results show that for mean neutron energy of 280 keV , the relative neutron response of the human tooth enamel ranges from 8% to 12% of the equivalent gamma ray response.