In this work we have studied the feasibility of photonuclear production of (47)Sc from (48)Ti via (48)Ti(γ,p)(47)Sc reaction. Photon flux distribution for electron beams of different energies incident on tungsten converter was calculated using MCNPX radiation transport code. (47)Sc production rate dependence on electron beam energy was found and (47)Sc yields were estimated. It was shown that irradiating a natural Ti target results in numerous scandium isotopes which can reduce the specific activity of (47)Sc. Irradiating enriched (48)Ti targets with a 22MeV 1mA beam will result in hundreds of MBq/g activity of (47)Sc and no other isotopes of scandium. Decreasing the size of the target will result in much higher average photon flux through the target and tens of GBq/g levels of specific activity of (47)Sc. Increasing the beam energy will also result in higher yields, but as soon as the electron energy exceeds the (48)Ti(γ,np)(46)Sc reaction threshold, (46)Sc starts being produced and its fraction in total scandium atoms grows as beam energy increases. The results of the simulations were benchmarked by irradiating natural titanium foil with 22MeV electron beam incident on the tungsten converter. Measured (47)Sc activities were found to be in very good agreement with the predictions.

The goal of this work was to determine the feasibility of using electron 7 linacs for transmutation of selective long-lived fission products (LLFP), par-8 ticularly 129 I. We have designed a converter system that produces both pho-9 tons and neutrons, thus creating a mixed radiation field. The strength of 10 the field depends on electron beam energy and current, as well as the con-11 verter material and geometry. The converter was optimized to maximize 12 transmutation rate of 129 I via two channels: 129 I(γ,n) 128 I and 129 I(n,γ) 130 I. 13 The optimum electron beam energy was found to be around 100 MeV. Com-14 puter simulations were benchmarked by experimental data on 133 Cs (129 I 15 surrogate) photon-induced and neutron-induced transmutation rates. While 16 further optimization of the system is necessary, we have demonstrated that 17 accelerator-driven photonuclear reactions can be practical for 129 I transmu-18 tation.

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Instrumental analytical methods are preferable in studying sub-milligram quantities of airborne particulates collected in dust filters. The multi-step analytical procedure used in treating samples through chemical separation can be quite complicated. Further, due to the minute masses of the airborne particulates collected on filters, such chemical treatment can easily lead to significant levels of contamination. Radio-analytical techniques, and in particular, activation analysis methods offer a far cleaner alternative. Activation methods require minimal sample preparation and provide sufficient sensitivity for detecting the vast majority of the elements throughout the periodic table. In this paper, we will give a general overview of the technique of photon activation analysis. We will show that by activating dust particles with 10-to 30-MeV bremsstrahlung photons, we can ascertain their elemental composition. The samples are embedded in dust-collection filters and are irradiated "as is" by these photons. The radioactivity of the photonuclear reaction products is measured with appropriate spectrometers and the respective analytes are quantified using multi-component calibration materials. We shall provide specific examples of identifying the elemental components of airborne dust particles and volcanic ash by making use of bremsstrahlung photons from an electron linear accelerator at the Idaho Accelerator Center in Pocatello, Idaho. .

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