Generated heat by different targets irradiated by 660 MeV protons

246-254Calorimetric experiments have been performed to analyze different thick targets of natU, C, Pb material, irradiated by 660 MeV protons at the Phasotron accelerator facility, Joint Institute for Nuclear Research (JINR) in Dubna, Russia. The method of online temperature measurement has been compared with MCNPX 2.7.0 simulation and selected with Ansys Transient Thermal Simulation to compare measured temperature with the simulated one. Thermocouples type T and E have been used as a temperature probe. Many different positions have been measured for each target. Temperature results are following very well the processes inside of the cylinders. Changes of heat deposition caused by drops of the proton beam intensity are displayed very well as a jagged line shown in almost every chart. Accurate temperature changing measurement is a very modest variation of how to observe inner macroscopic behavior online

The experimental determination of heavy metal nuclei fission reactions cross sections at 0.66 GeV protons beam

Cross sections of fission reactions of ¹⁹⁷Au, ²⁰⁷Pb, ²⁰⁹Bi, ²³²Th, ²³⁸U heavy metals induced by protons with energy of 0.66 GeV are presented. The protons beam was extracted from the Phasotron accelerator at JINR, Dubna, Russian Federation. Fission reactions cross sections were measured using solid state nuclear track detectors (SSNTD) and activation gamma-spectroscopy. The comparison with results from others researchers were done. The obtained results would be added in the international databases for testing of programme code for ADS-systems.Представлені експериментальні дані по перетинах реакцій поділу ядер важких металів ¹⁹⁷Au, ²⁰⁷Pb, ²⁰⁹Bi, ²³²Th, ²³⁸U під дією протонів з енергією 0,66 ГеВ. Експерименти проведені на пучках протонів прискорювача Фазатрон, ОІЯД, Дубна, РФ. Для визначення перетинів реакцій поділу використана комплексна методика твердотільних трекових детекторів ядер і активаціонної гамма-спектрометрії. Виконано порівняння отриманих результатів з результатами інших дослідників. Отримані результати доповнять базу експериментальних ядерних даних, що дозволить протестувати комп'ютерні коди, що застосовуються при розрахунках параметрів ADS.Представлены экспериментальные данные по сечениям реакций деления ядер тяжелых металлов ¹⁹⁷Au, ²⁰⁷Pb, ²⁰⁹Bi, ²³²Th, ²³⁸U под действием протонов с энергией 0,66 ГэВ. Эксперименты проведены на пучках протонов ускорителя Фазатрон, ОИЯИ, Дубна, РФ. Для определения сечений реакций деления использована комплексная методика твердотельных трековых детекторов ядер и активационной гамма-спектрометрии. Выполнено сравнение полученных результатов с результатами других исследователей. Полученные результаты дополнят базу экспериментальных ядерных данных, что позволит протестировать компьютерные коды, применяемые при расчетах параметров ADS

Monitoring mixed neutron-proton field near the primary proton and deuteron beams in spallation targets

282-293At the Joint Institute for Nuclear Research (JINR) we are involved in the Accelerator-Driven-System (ADS) research. We perform experiments with assemblies composed of a spallation target and a subcritical blanket irradiated with high-energy proton or deuteron beams that generate high-energy neutron fields by spallation and fission reactions. In this paper, three uranium assemblies are presented: Energy plus Transmutation (E+T), QUINTA and BURAN. We discuss the results of the E+T and QUINTA irradiations by 1.6 GeV deuterons and 660 MeV protons, respectively. We have focused on the regions close to the primary beam passage through the targets. The field has been measured using activation detectors of 209Bi, 59Co, and natPb. Monte Carlo simulations using MCNPX 2.7.0 have been performed and compared to the experimental results. We discovered that the field intensity near the primary beam is very dependent on the precision of the accelerator beam settings. Therefore, a Monte Carlo-based study of the influence of the uncertainty of primary proton beam parameters on experimental result accuracy of the QUINTA assembly has been carried out. The usage of MCNPX 2.7.0 in the future BURAN irradiations has been assessed.</span

Generated heat by different targets irradiated by 660 MeV protons

Calorimetric experiments have been performed to analyze different thick targets of natU, C, Pb material, irradiated by 660 MeV protons at the Phasotron accelerator facility, Joint Institute for Nuclear Research (JINR) in Dubna, Russia. The method of online temperature measurement has been compared with MCNPX 2.7.0 simulation and selected with Ansys Transient Thermal Simulation to compare measured temperature with the simulated one. Thermocouples type T and E have been used as a temperature probe. Many different positions have been measured for each target. Temperature results are following very well the processes inside of the cylinders. Changes of heat deposition caused by drops of the proton beam intensity are displayed very well as a jagged line shown in almost every chart. Accurate temperature changing measurement is a very modest variation of how to observe inner macroscopic behavior online

An Investigation of Products of (n, ƒ), (n, ɣ) and (ɣ, ƒ), (ɣ, xn, p) Reactions on Samples of Uranium and Bismuth using the Phasotron and LINAС-200 Accelerators at JINR: Experiments and Calculations

The paper presents the results of physical experiments with 238U and 209Bi samples at the Nuclotron, Phasotron and LINAC-200 accelerators of the Joint Institute for Nuclear Research, with the results processed using the FLUKA, GEANT4 and MCNP programs

Enhanced magnetoresistive effect in the arrays of nickel nanorods on silicon substrates

It is shown that the magnetoresistive properties of n–Si/SiO2/Ni, nanostructures containing nanogranular nickel rods in a SiO2 layer’s vertical pores substantially differ from the similar properties in the earlier studied nanogranular Ni films electrodeposited onto the n–Si plates. From the point of view of the electrophysical properties, the nanostructures studied are analogous to a system of two Schottky Si/Ni diodes, which are connected to each other. The magnetoresistance of such structures has been studied in the temperature range from 2 to 300 K and the magnetic field range of up to 8 Tl. It is established that at temperatures of 17–27 K the structures possess a positive magnetoresistive effect, whose value depends on the transverse voltage applied to the structure and increases with a decrease in the longitudinal (along the rods) current intensity. At a current of 100 nA, the relative magnetoresistance in the field of 8 Tl increases from 500 to 35000% by an increase in the transverse voltage from 0 to –2 V. The observed magnetoresistive effect is associated with the influence of the magnetic field on the processes of impact ionization of impurities resulting in an avalanche breakdown of the Ni/Si Schottky barrier. Thus, the possibility of controlling the magnetoresistive effect in n–Si/SiO2/Ni template structures by applying an additional (transverse) electric field to the nanostructure between the silicon substrate (as the third electrode) and nickel rods is proven

Monitoring mixed neutron-proton field near the primary proton and deuteron beams in spallation targets

At the Joint Institute for Nuclear Research (JINR) we are involved in the Accelerator-Driven-System (ADS) research. We perform experiments with assemblies composed of a spallation target and a subcritical blanket irradiated with high-energy proton or deuteron beams that generate high-energy neutron fields by spallation and fission reactions. In this paper, three uranium assemblies are presented: Energy plus Transmutation (E+T), QUINTA and BURAN. We discuss the results of the E+T and QUINTA irradiations by 1.6 GeV deuterons and 660 MeV protons, respectively. We have focused on the regions close to the primary beam passage through the targets. The field has been measured using activation detectors of 209Bi, 59Co, and natPb. Monte Carlo simulations using MCNPX 2.7.0 have been performed and compared to the experimental results. We discovered that the field intensity near the primary beam is very dependent on the precision of the accelerator beam settings. Therefore, a Monte Carlo-based study of the influence of the uncertainty of primary proton beam parameters on experimental result accuracy of the QUINTA assembly has been carried out. The usage of MCNPX 2.7.0 in the future BURAN irradiations has been assessed