Airborne gaseous 13N species and noxious gases produced at the 12 GeV proton synchrotron

The irradiation of atmospheric air with high-energy protons has been performed at the 12 GeV proton synchrotron. The specific activity of 13 N, one of the principal airborne radioactivities, was measured as a function of the irradiation time at a dose rate of about 6·10 16 eV/g/s, and compared with the calculated values. The predominant chemical species of 13 N produced were found to be 13 N 2 and 13 NO 2 . Their proportions were approximately 55% for 13 N 2 and 45% for 13 NO 2 , being almost independent of the irradiation time. Smaller quantities of 13 NO and H 13 NO 2 were also observed. Measurements of radiolytic products showed that ozone is a main product and that NO 2 predominates among the products of nitrogen compounds, including HNO 2 and HNO 3 . The G-value for ozone formation in air was estimated from the experimental data as 6.4 molecules/100 eV.