Sergey I. Tyutyunnikov

Studies of deuteron and neutron cross-sections important for ADS research

The collaboration Energy and Transmutation of Radioactive Waste uses different setups consisting of lead, natural uranium and graphite irradiated by relativistic protons and deuterons to study transmutation of radioactive materials by produced neutrons. The activation samples are used to determine integral of proton or deuteron beams and also produced neutron flux in different places of experimental set-ups. Unfortunately almost no experimental cross-section data for deuterons with GeV energies are available. The similar situation is also for threshold (n,xn) reactions of neutrons with higher energies. Therefore we carried out series of experiments devoted to determination of deuteron reactions on copper during uranium target QUINTA irradiations by deuterons with energies from 1 GeV up to 8 GeV. The cross-sections of various threshold reactions were studied by means of different quasi-monoenergetic neutron sources with possible energies from 14 MeV up to 100 MeV. Knowledge of such cross-sections is very important for all Accelerator Driven System studies.

Simulation of neutron production in heavy metal targets using Geant4 software

Inelastic hadronic interactions in heavy targets have been simulated using Geant4 and compared with experimental data for thin and thick lead and uranium targets. Special attention is paid to neutron and fission fragment production. Good agreement in the description of proton-beam interaction with thick targets is demonstrated, which is important for the simulation of experiments aimed at the development of subcritical reactors.

Monitoring extracted beams of the nuclotron accelerator complex for “energy + transmutation” experiments

A monitoring system for measuring absolute intensity and the space—time structure of extracted beams of Nuclotron based on ionization and activation methods has been created and tested. The monitoring system provides a measurement of the absolute intensity of extracted beams with a precision of 10% and beam position with a precision of 0.5 mm.

Monte Carlo simulations and experimental results on neutron production in the uranium spallation target QUINTA irradiated with 660 MeV protons

The activation experiment was performed using the accelerated beam of Phasotron accelerator at the Joint Institute for Nuclear Research (JINR). The natural uranium spallation target QUINTA was irradiated with protons with energy 660 MeV. Monte Carlo simulations of neutron production were performed using the Geant4 code. The number of leakage neutrons from the sections of the uranium target surrounded by the lead shielding and the number of leakage neutrons from lead were determined. The total number of fissions in the setup QUINTA was determined. Experimental values of reaction rates for the produced nuclei in the 127I sample were obtained and several values of reaction rates were compared with the results of simulations. Experimentally determined fluence of neutrons in energy interval 10-175 MeV using the (n,xn) reactions in the 127I(NaI) sample was compared with the results of simulations. Possibility of transmutation of the long-lived radionuclide 129I in the QUINTA setup was estimated.

Optimization of accelerated charged particle beam for ADS energy production

A comparative analysis and optimization of energy efficiency for proton and ion beams in ADS systems is performed via simulation using a GEANT4 code with account for energy consumption for different accelerator types. It is demonstrated that for light nuclei, beginning from 7Li, with energies above 1 GeV/nucleon, ion beams are considerably (several times) more efficient than the 1–3 GeV proton beam. The possibility of achieving energy deposition equivalent to 1 GeV protons in a quasi-infinite uranium target with higher efficiency (and twice as small accelerator size) in the case of acceleration of light ions is substantiated.

Determination of the neutron flux by the temperature differences at the massive spallation uranium target QUINTA

There are several possibilities of the neutron flux determination inside of the facility. The most using one method is the determination of the neutron flux by threshold foils (detectors). This method is complicated to analyze. Irradiated foils need to be measured by gamma spectrometry and it usually takes a few weeks to get results of the neutron flux determination. Other methods are also available. One of them is the determination of the neutron flux by measuring of released heat inside of the facility. This method allows online measuring and is greatly variable to measure an unlimited number of positions in the facility with a low accrual of the cost. The research project to the topic of this type of neutron flux determination is led by Dzhelepov Laboratory of Nuclear Problems (DLNP) at the group of J. Adam. The temperature differences are measured by high accuracy thermocouples. Two experiments took place during 2015 at the massive spallation uranium target QUINTA at the facility Phasotron at JINR. Another four experiments are planned during 2016.

Neutron Flux Determination By High Accuracy Temperature Measurement

This paper is focused on the description of developing a method to determine neutron flux by high-accuracy temperature measurement. The paper deals with the procedure of sophisticated measurement, its analyzation and brings part of reached results. The method is in development in the research group aimed at ADS in the DLNP, JINR. Since the first experiment in November 2015, another 5 experiments have been performed and due to progress, the future experiment seems to be closer to reach relatively cheap probe with the ability to determine the neutron flux online.

Determination And Monte Carlo Simulations Of Neutron Flux Inside Spallation Target Quinta

This paper deals with experiments performed with natural uranium spallation target QUINTA irradiated by 4 GeV and 8 GeV deuteron beam from Nuclotron accelerator and by 660 MeV proton beam from Phasotron accelerator. Reaction rates for Na-24, Co-57, Co-58, Bi-205 and Bi-206 production in Al, Co and Pb threshold radioactivation foils were determined. The data served for calculation of the experimental neutron flux inside the QUINTA target for the Phasotron experiment. Simulations in Monte Carlo code MCNPX 2.7 were performed and compared to the experimental data. In the current state of research, the data evaluation and simulations are preliminary.

Multipurpose synchrotron spectrometer of the Kurchatov Institute: Part 2. X-ray fluorescent element analysis

The performance of the Kurchatov Institute’s multiporpose synchrotron spectrometer is diversified by adding the equipment for the X-ray fluorescent element analysis. The X-ray optical focusing system of the spectrometer is described. The analysis results for the copper, lead, and gold-nanofilm samples are reported.

Multipurpose synchrotron spectrometer of the Kurchatov Institute: Part 3. Diffraction in Debye–Scherrer geometry

The performance of a multipurpose synchrotron spectrometer is diversified by installing additional equipment for the studies of diffraction in the Debye–Scherrer geometry. The design of X-ray optics and technical characteristics of the spectrometer are described. Diffraction patterns for polycrystals detected in both the forward and backward hemispheres are illustrated.