A project of a gamma-ray spectrometric system for diagnosing fast particles in the TRT tokamak plasma is described. The organizational concept of gamma spectrometric measurements is proposed. ...Preliminary results of calculating the intensities of gamma ray lines of hydrogen, deuterium, and deuterium–tritium plasmas are presented, which demonstrate the possibility of obtaining information about the energy and spatial distribution of fast ions with a time resolution of 1–10 s when using a multidetector system. Runaway electrons can be observed by hard X-ray emission from the tokamak plasma in the megaelectronvolt range.
Analysis of the LaCl3(Ce) scintillator response function to fast neutrons Pankratenko, A.V.; Kormilitsyn, T.M.; Kashuck, Yu.A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
July 2023, 2023-07-00, Volume:
1052
Journal Article
Peer reviewed
LaCl3(Ce) scintillator is a novel solution to the task of the fast neutron spectrometry applicable primarily for the nuclear fusion experiments. In the interest of proper neutron spectrum ...reconstruction, the detector response function has to be studied in detail. This work is focused on the detector response measurement and modelling under fast neutrons born in the 9Be(α, n)12C reaction at Ioffe Institute cyclotron. Comparative analysis of measured spectra versus model is done, the energy resolution and the p/β ratio are estimated for neutron energies of up to 8.5 MeV. The energy resolution is calculated to be 7–8% at 5–8 MeV. The p/β coefficient is estimated, growing from ∼0.75 at 2 MeV to ∼0.85 at 8.5 MeV. These results demonstrate the usability of the LaCl3(Ce) crystal as a neutron spectrometer at DD-neutron energies under γ-ray irradiation. At higher energies, due to low cross-sections and a multitude of possible reaction channels, the suitability of this crystal as a spectrometer is lowered.
•LaCl3(Ce) is a scintillator capable of DD-neutron spectrometry.•Measured resolution is ∼7%, p/β∼0.7–0.8.•The detector performs worse at En>3 MeV.
Gamma ray spectrometry measurements at high detector counting rates (on the order of 107 s−1 and higher) are relevant for high-temperature plasma diagnostics for existing tokamaks and during the ...development of gamma ray diagnostic systems for the ITER tokamak under construction. At high loads, to obtain spectra without distortion and with a small amount of dead time, it is necessary to use advanced scintillation detector signal processing methods, which can resolve superimposed pulses. Two algorithms that can be used for digital signal processing of scintillation gamma ray detectors with many piled-up pulses are considered in this article, the fitting and deconvolution methods. These algorithms are compared with both one another and two less sophisticated pulse-height analysis algorithms (maximum height and total sum under the peak) in applications that process model and measured signals. Baseline detection algorithms are also considered, which are necessary when processing signals from detectors. The algorithms are applied to LaBr3(Ce) detector signal processing. For the modeled signals, the best results in terms of the number of resolved events and energy resolution at counting rates up to 2 × 107 s−1 of the LaBr3(Ce) detector are demonstrated by the fitting method. In the real gamma ray measurements at a loading of 5.1 106 s−1, the deconvolution method demonstrated the best energy resolution.
Abstract The fusion reaction between deuterium and tritium, D ( T,n ) 4 He is the main source of energy in future thermonuclear reactors. Alpha-particles ( 4 He -ions) born with an average energy of ...3.5 MeV transferring energy to the thermal plasma during their slowing down, should provide the self-sustained D–T plasma burn. The adequate confinement of α -particles is essential to provide efficient heating of the bulk plasma and steady burning of a reactor plasma. That is why the fusion-born α -particle studies have been a priority task in the second D–T experiments (DTE2) on the Joint European Torus (JET) to understand the main mechanisms of their slowing down, redistribution and losses and to develop optimal plasma scenarios. JET with Be -wall and W -divertor, enhanced auxiliary heating systems and improved energetic-particle diagnostic capabilities, producing significant population of α -particles, provided the possibility for comprehensive studying of the α -particle behaviour. Selected results of the confined and lost α -particle measurements, evidence of α -particle self-heating and assessments of the fusion performance are presented in this paper giving an opportunity for further modelling and extrapolation to the International Thermonuclear Experimental Reactor and burning plasma reactors.
Two neutron spectrometers based on a BC-501A liquid organic scintillator were calibrated. The calibration procedure included obtaining the spectrometers’ response functions to monoenergetic neutron ...emissions and estimating the detectors’ efficiency and is described in this paper. A 9Be(α, nγ)12C nuclear reaction was used as the neutron source. Simultaneous registration of neutrons and gamma quanta with 4.44 MeV energy enabled the extraction of monoenergetic neutrons corresponding to the first excited state of a 12C nucleus. This process is the basis of the neutron–gamma coincidence method, which was applied in the present experiments. The experiments were conducted using the cyclotron at Ioffe Institute, where α particles were accelerated to energies of 2.06, 5.35, 6.05, and 10.08 MeV. The angular dependence of the energy of produced neutrons provided a wide energy range of monoenergetic neutron emission at the same energy of the incident α particle. The response functions of the BC-501A spectrometers on the monoenergetic neutrons were obtained at energies of 1.9 to 10.4 MeV. The neutron registration efficiency of both detectors was estimated in the same energy range as the responses.
First Globus-M2 Results Bakharev, N. N.; Balachenkov, I. M.; Chernyshev, F. V. ...
Plasma physics reports,
07/2020, Volume:
46, Issue:
7
Journal Article
Peer reviewed
Globus-M2—a new 1-Tesla spherical tokamak—was recently launched. The main features and research directions of this machine in scope of fusion–fission reactor development are described. Main results ...of the first experimental campaign with toroidal magnetic field up to 0.73 T and plasma current up to 0.33 MA are discussed. Significant improvement of the discharge parameters as compared to Globus-M was achieved. Plasma total stored energy higher than 7 kJ was obtained. Energy confinement time increase was consistent with predictions by spherical tokamak scalings. Toroidal Alfvén eigenmode-induced losses decrease with increase of plasma current and toroidal magnetic field. For the first time, LHCD with the toroidal wave slowing-down was successfully used at a spherical tokamak.
Neutron diagnostic system at the Globus-M2 tokamak Iliasova, M.V.; Shevelev, A.E.; Khilkevitch, E.M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2022, Volume:
1029
Journal Article
Peer reviewed
A neutron diagnostic system was developed at the Ioffe Institute as part of the Globus-M2 tokamak to optimize NBI heating conditions and evaluate heating efficiency. The system contains two compact ...neutron spectrometers based on the liquid organic scintillator BC-501A and two gas-discharge counters based on a 10B isotope. The BC-501A spectrometers were calibrated by measuring neutron emission produced in a 9Be(α,n)12C nuclear reaction on the cyclotron facility at the Ioffe Institute. In addition, in situ calibrations of the system, including the neutron spectrometers and the gas-discharge counters, was carried out using an Am–Be neutron source to provide accurate measurements of the total neutron yield from the plasma of the Globus-M2 tokamak. During the plasma experiments at the Globus-M2 tokamak, a deuterium beam was injected into the deuterium plasma that causes a yield of the DD-neutrons with ∼2.45 MeV energy. The neutron spectrometry diagnostic system was used to provide neutron measurements and detect the DD-neutrons in these experiments. The neutron yield and the DD-reaction rate during plasma discharges were evaluated. The energy distributions of neutrons emitted from plasma during discharges with neutron beam injection were reconstructed from the measured neutron spectra.
