Young-Sik Cho

Experimental determination of proton-induced cross-sections on natural zirconium

We measured cross-sections for the formation of (86g,87m,87g)Y, (88,89g)Zr, and (90,92m)Nb radionuclides for proton-induced reactions on natural zirconium by using a conventional stacked-foil activation technique in the energy range between 1 and 40MeV at the MC-50 cyclotron of the Korea Institute of Radiological and Medical Science. We compared the measured data with the available literature data and the theoretical calculation by the model codes TALYS and ALICE-IPPE. We also deduced the integral yields for thick targets from the measured cross-sections of the produced radionuclides. The optimum production possibility of the medically important (89g)Zr and (86)Y radionuclides were discussed elaborately.

Investigations of the natTi(p,x)43,44m,44g,46,47,48Sc,48V nuclear processes up to 40 MeV

Independent and cumulative production cross-sections for the (nat)Ti(p,x)(48)V, (43,44m,44g,46,47,48)Sc nuclear processes are reported here, for the energy region of 4-38MeV by using a stacked-foil activation technique. Measured data were critically compared with the earlier reported values, and also with the theoretical data from the TALYS and ALICE-IPPE codes. The measured (nat)Ti(p,x)(48)V reaction is important for charged particle beam monitoring purposes, whereas the (43,44,47)Sc radionuclide have various practical applications in nuclear medicine.

INITIAL ESTIMATION OF THE RADIONUCLIDES IN THE SOIL AROUND THE 100 MEV PROTON ACCELERATOR FACILITY OF PEFP

The Proton Engineering Frontier Project (PEFP) has designed and developed a proton linear accelerator facility operating at 100 MeV - 20 mA. The radiological effects of such a nuclear facility on the environment are important in terms of radiation safety. This study estimated the production rates of radionuclides in the soil around the accelerator facility using MCNPX. The groundwater migration of the radioisotopes was also calculated using the Concentration Model. Several spallation reactions have occurred due to leaked neutrons, leading to the release of various radionuclides into the soil. The total activity of the induced radionuclides is approximately at the point of saturation. had the highest production rate with a specific activity of over the course of one year. and are usually considered the most important radioisotopes at nuclear facilities. However, only a small amount of tritium was produced around this facility, as the energy of most neutrons is below the threshold of the predominant reactions for producing tritium: and (approximately 20 MeV). The dose level of drinking water from was pCi/ml/yr, which was less than the annual intake limit in the regulations.

Production Cross Sections of 186Re Radionuclide from the Proton Bombardment on Natural Tungsten

The excitation function of the natW(p,xn)186Re nuclear reaction was measured as a function of the proton energy in the range of 6 - 40 MeV by using a stacked-foil activation technique combined with high-purity germanium gamma-ray spectroscopy at the MC50 cyclotron of the Korea Institute of Radiological and Medical Sciences. The present results are in good agreement with the earlier reported experimental data and the theoretical calculation based on the TALYS code. The thick target integral yield was also deduced from the measured excitation function and stopping power of natW over the energy range from threshold up to 40 MeV.

The Calculation of Neutron Scattering Cross Sections for Silicon and Bismuth Crystal at Thermal Energies

Silicon and bismuth crystals are often used as effective thermal neutron filters. They crystallize in a diamondlike structure and a rhombohedral structure, respectively. It is necessary to determine the characteristics of their thermal neutron scattering to understand their properties as a filter. NJOY is widely used as a nuclear data processing tool, and has a built-in module named LEAPR which is able to calculate thermal scattering cross sections for materials of hep (hexagonal close packed) lattices such as beryllium. The module LEAPR can be used to calculate the thermal inelastic scattering cross sections for silicon and bismuth crystals with user defined data for the phonon frequency spectrum. However, the code cannot exactly compute the thermal elastic scattering cross sections for those crystals because the module does not take into account their crystal structures on which elastic scattering sensitively depends. In the present article, the module LEAPR is improved to have the capability of computing the thermal elastic scattering cross sections for silicon and bismuth crystals. The calculation formulae for thermal neutron elastic scattering were derived and incorporated into LEAPR, and then the scattering cross sections were computed. The results were in good agreement with experimental data.