Experimental investigation and Monte Carlo simulations of radionuclide production inside the Uranium spallation target QUINTA irradiated with a 660-MeV proton beam

The accelerator-Driven-System (ADS) is very important to study the neutron field and radionuclide production inside simple-geometry uranium subcritical setups irradiated with high energy particle beams. A subcritical setup QUINTA was irradiated with the 660-MeV proton beam from Phasotron accelerator at the Joint Institute for Nuclear Research (JINR). The radionuclide production in the region along the beam axis was investigated by the activation technique. The aim was to compare (n,x) with (p,x) reactions using activation detectors of 59Co and natPb, and compare experimental results with the calculated results using Monte Carlo simulation code MCNPX 2.7

Cross-sections of residual nuclei from deuteron irradiation of thin thorium target at energy 7 GeV

The residual nuclei yields are of great importance for the estimation of basic radiation-technology characteristics (like a total target activity, production of long-lived nuclides etc.) of accelerator driven systems planned for transmutation of spent nuclear fuel and for a design of radioisotopes production facilities. Experimental data are also essential for validation of nuclear codes describing various stages of a spallation reaction. Therefore, the main aim of this work is to add new experimental data in energy region of relativistic deuterons, as similar data are missing in nuclear databases. The sample made of thin natural thorium foil was irradiated at JINR Nuclotron accelerator with a deuteron beam of the total kinetic energy 7 GeV. Integral number of deuterons was determined with the use of aluminum activation detectors. Products of deuteron induced spallation reaction were qualified and quantified by means of gamma-ray spectroscopy method. Several important spectroscopic corrections were applied to obtain results of high accuracy. Experimental cumulative and independent cross-sections were determined for more than 80 isotopes including meta-stable isomers. The total uncertainty of results rarely exceeded 9%. Experimental results were compared with MCNP6.1 Monte-Carlo code predictions. Generally, experimental and calculated cross-sections are in a reasonably good agreement, with the exception of a few light isotopes in a fragmentation region, where the calculations are highly under-estimated. Measured data will be useful for future development of high-energy nuclear codes. After completion, final data will be added into the EXFOR database

Cross-sections of residual nuclei from deuteron irradiation of thin thorium target at energy 7 GeV

The residual nuclei yields are of great importance for the estimation of basic radiation-technology characteristics (like a total target activity, production of long-lived nuclides etc.) of accelerator driven systems planned for transmutation of spent nuclear fuel and for a design of radioisotopes production facilities. Experimental data are also essential for validation of nuclear codes describing various stages of a spallation reaction. Therefore, the main aim of this work is to add new experimental data in energy region of relativistic deuterons, as similar data are missing in nuclear databases. The sample made of thin natural thorium foil was irradiated at JINR Nuclotron accelerator with a deuteron beam of the total kinetic energy 7 GeV. Integral number of deuterons was determined with the use of aluminum activation detectors. Products of deuteron induced spallation reaction were qualified and quantified by means of gamma-ray spectroscopy method. Several important spectroscopic corrections were applied to obtain results of high accuracy. Experimental cumulative and independent cross-sections were determined for more than 80 isotopes including meta-stable isomers. The total uncertainty of results rarely exceeded 9%. Experimental results were compared with MCNP6.1 Monte-Carlo code predictions. Generally, experimental and calculated cross-sections are in a reasonably good agreement, with the exception of a few light isotopes in a fragmentation region, where the calculations are highly under-estimated. Measured data will be useful for future development of high-energy nuclear codes. After completion, final data will be added into the EXFOR database

Distribution of neutrons and protons in elongated targets

Analysis of neutron distribution was carried out for two elongated targets. The targets have cylindrical shape and are made of lead and carbon, respectively. The dimensions are approximately one meter in length and 19 cm in diameter. The targets were irradiated with 660 MeV proton beam at Phasotron accelerator at the Joint Institute for Nuclear Research. The total number of protons was 2.35(18)E15 for the experiment with carbon target and the total number of particles at the second experiment was 2.32(19)E15. The produced neutron field was monitored by cobalt threshold activation detectors at various positions. The activation detectors were measured by means of gamma spectroscopy using HPGe detectors. Reaction rates of different radionuclides produced in the activation detectors were determined and the results from both experiments were compared. The ratios were calculated for 7 reactions produced in cobalt detectors. The ratio of the reaction rates shows that the number of residual nuclei with higher threshold energies is higher for experiment with carbon target than for the experiment with the lead target

Distribution of neutrons and protons in elongated targets

Analysis of neutron distribution was carried out for two elongated targets. The targets have cylindrical shape and are made of lead and carbon, respectively. The dimensions are approximately one meter in length and 19 cm in diameter. The targets were irradiated with 660 MeV proton beam at Phasotron accelerator at the Joint Institute for Nuclear Research. The total number of protons was 2.35(18)E15 for the experiment with carbon target and the total number of particles at the second experiment was 2.32(19)E15. The produced neutron field was monitored by cobalt threshold activation detectors at various positions. The activation detectors were measured by means of gamma spectroscopy using HPGe detectors. Reaction rates of different radionuclides produced in the activation detectors were determined and the results from both experiments were compared. The ratios were calculated for 7 reactions produced in cobalt detectors. The ratio of the reaction rates shows that the number of residual nuclei with higher threshold energies is higher for experiment with carbon target than for the experiment with the lead target