Institute Of Nuclear Physics Research Articles

Broadband Signal Amplification Paths for Semiconductor Radiation and Particle Detectors (Review)

This study is devoted to the development of amplifying paths for plasma diagnostics, a significant part of which use semiconductor detectors as sensors that form low-intensity current signals. One feature of these diagnostics is the oscillographic form of registering sensor signals. In tandem with detectors, broadband transimpedance amplifiers that are based on operational amplifiers are used to amplify and normalize sensor signals. The principles of constructing such amplifying paths are considered taking the factors affecting their final noise and frequency characteristics into account. Practical examples of the construction of amplifying paths of corpuscular and neutron plasma diagnostics, as well as the Thomson-scattering diagnostics, that are used at the plasma installations of the Institute of Nuclear Physics (Siberian Branch, Russian Academy of Sciences) are presented.

First person – Rajdeep Das

ABSTRACT First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Rajdeep Das is first author on ‘ MITOL-mediated DRP1 ubiquitylation and degradation promotes mitochondrial hyperfusion in a CMT2A-linked MFN2 mutant’, published in JCS. Rajdeep is a senior research fellow in the lab of Professor Oishee Chakrabarti at the Saha Institute of Nuclear Physics, Kolkata, India, investigating mitochondrial dynamics and cellular trafficking.

Plasma flow suppression by the linear helical mirror system

The paper presents experimental results from the SMOLA device that is the first facility with a helical mirror section of the magnetic system. This device was built in the Budker Institute of Nuclear Physics for the verification of the helical mirror confinement idea that is the technique of an active control of axial losses from a confinement zone. Theory predicts that, with rotating plasma, a helical mirror will provide suppression of the axial plasma flow and, simultaneously, density pinching to the axis. Experiments demonstrated the increase in plasma density in the entrance trap by a factor of 1.6 in the helical configuration. The integral axial flux from the transport section drops severalfold. The effective mirror ratio of the helical section was $R_{eff} > 10$ . Particle flux returning by the helical mirror section towards the confinement zone was observed. At high corrugation ratios, the axial flux direction is different at the magnetic axis and in the periphery of the plasma in the helical section. All axial fluxes scale linearly with the plasma density, even if the ion mean free path is comparable to the total length of the helical section. Good agreement of the experimental results with theoretical predictions is found.

Technique for obtaining an integral characteristic of the structure of a loaded composite material based on microtomographic research data

Composite materials are characterized by an uneven distribution of the density value in the volume. Under mechanical loading, the parameters of the density distribution over the volume change, which leads to qualitative changes in the structure up to the formation of discontinuities, and the shock-wave sensitivity also changes accordingly. The exact distribution of regions with different density values in the bulk of the material is established by means of X-ray microtomography.The purpose of the work was to develop a technique for obtaining an integral characteristic of the structure of a loaded composite material based on microtomographic examination data. Samples of a carbon composite material in the initial state and subjected to loading with various degrees of deformation were used as objects of study. Synchrotron radiation from a VEPP-3 charged particle accelerator (Institute of Nuclear Physics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia) was used as an X-ray source for microtomographic studies.To extract the indicated integral characteristic of the structure from the density matrices of the material, an image analysis technique was developed based on sequential image filtering in order to select regions with a given range of gray shades from the total matrix. To decompose the general matrix into derivatives and their subsequent analysis, the universal software ImageJ-FiJi was used.Based on the processing results, a dependence was obtained that characterizes the ratio of the size of the local region of the structure with a characteristic density value to the distance between these regions, that is, the desired integral characteristic from the conditional density range of the analyzed regions.

Measurement of the spatial-energy distribution of neutrons in the irradiation channel of the critical facility

One of the basic installations of the Republican State Enterprise “Institute of Nuclear Physics” of the Ministry of Energy of the Republic of Kazakhstan is a critical assembly, which is a zero-power reactor. Desalinated water and beryllium serve as moderators and neutrons reflectors. The energy spectrum of neutrons in the core is thermal. The main purpose and area of application is the modeling and study of the neutronic characteristics of the cores of water-moderated research reactors of various types.The paper presents the results of experimental measurements of the spatial-energy distribution of neutrons in the dry, central channel of the critical assembly. Measurements of the neutron flux were carried out using activation foils for three energy groups of neutrons: thermal, epithermal, and fast.The measured thermal neutrons flux in the irradiation channel is ~ 3·108 cm‒2s‒1, and fast neutrons flux (with energies above 0.7 MeV) is ~ 8·108 cm‒2s‒1. The fraction of thermal neutrons in the integral flux was 0.23%, and the fraction of fast neutrons was 0.62%. In the axial distribution of thermal and fast neutrons, the maximum value of the neutron flux is 50 mm below the midplane of the core.

Effects of Boron Neutron Capture Therapy on the Growth of Subcutaneous Xenografts of Human Colorectal Adenocarcinoma SW-620 in Immunodeficient Mice.

Boron neutron capture therapy (BNCT) can become an instrument for patients with malignant neoplasms of the rectum and colon. Here we evaluate the effectiveness of BNCT performed at the accelerator based epithermal neutron source at G. I. Budker Institute of Nuclear Physics, Siberian Division of Russian Academy of Sciences, in relation to subcutaneous xenografts of human colon adenocarcinoma SW-620 in SCID mice. Utilization of BNCT with boronоphenylalanine (BPA) and sodium borocaptate (BSH), which were injected intravenously into the retroorbital sinus, resulted in a significant decrease in tumor volumes compared to the control group (no radiation).

Preface

(word. doc) should be separate from the PDFs and include information about their virtual format if this is relevant. This information should include:• The reason(s) why the meeting will take/took place virtually (covid- 19/travel restrictions, etc). • The Forum was held both online and offline. All participants who took part offline provided vaccination certificates. The online forum was held for participants who did not have the opportunity to participate in the forum directly or to submit a report in person. Including, in order to be able for the majority of participants to participate in the Forum in a format convenient for them.• Location where the organisers will be/were. • The Forum was held on the premises of the Institute of Nuclear Physics in Almaty, Kazakhstan• The Model, for example, the plenary, the contributions, the time spent to deliver the talks by each speaker. • • The version of the poster or oral presentation was adopted as a model of reports, both online and offline. Plenary lectures were conducted both online and offline, through the presentation and oral presentation of the speaker. In each section, the time for a report was different, on average it ranged from 20 to 30 minutes.• The discussions, the feasibility, room for Q&A? • All questions and discussions were held in conference halls of 5 sections. Including online. Everyone could ask a question and get an answer, upon completion of the report, 10-15 minutes were allotted for this procedure.• The participants: location and the overall attendance number expected. • The participants took part in the forum on the territory of the Institute of Nuclear Physics. Within 5 days, more than 90% of the participants took part offline. There were more than 90 offline participants in total. In general, about 300 applications were accepted for participation in the forum.• The technology needed to deliver the meeting successfully. • The Forum was provided with the most modern technical equipment. Each section contained several projectors, computers and microphone sets for the participants. To ensure high parallelization of communication, high-speed Internet access was used for each 4G section.• Mention any technical difficulties. • • Technical difficulties during the forum were minor and were resolved as they arose. All forum participants appreciated the high level of technical equipment of the forum.• Mention any drawbacks in the delivery of the conference virtually, e.g. impact on the community. • No shortcomings were identified during the forum. The forum had an extremely positive impact on the public, which was mentioned in his speech for the journalists of the national channel, the chairman of the forum and the general director of the INP Batyrzhan Karakozov. Please make sure that the following information is included in the preface: l. The full list of committees names and affiliations which shall be published as part of the preface. Editors of proceedings, ORGANISING COMMITTEE, INTERNATIONAL ADVISORY BOARD, and ORGANIZED BY are available in the pdf.

Luminescence efficiency of cerium-doped yttrium aluminum garnet ceramics formed by radiation assisted synthesis

The variety of applications of yttrium-aluminum garnet (YAG)-based luminescent materials and the morphology necessary for these purposes required the development of many technologies for their synthesis. All synthesis technologies used are complex. The structural phase of yttrium-aluminum garnet is formed with any technology, at temperatures exceeding 1,500 °C. The starting materials for the synthesis are metal oxides of aluminum, yttrium and other oxides for activation and modification. It seems possible to use hard radiation to form a new phase. Radiation synthesis of ceramics is realized in less than 1 s, without the use of any additives and influences. The synthesis was carried out at the electron accelerator of the Institute of Nuclear Physics (Novosibirsk). In this work, we studied the spectral-kinetic and quantitative characteristics of luminescence for the first time obtained by the method of radiation synthesis of ceramic samples of yttrium-aluminum garnet doped with cerium with statistical processing of their values. The dependences of the reproducibility of the spectral characteristics of the luminescence of the samples on the preliminary preparation of the charge for synthesis have been investigated. Several cycles of luminophore brightness studies have been performed. It is shown that the obtained ceramics based on yttrium-aluminum garnet doped with cerium possesses the required spectral-kinetic properties, and the efficiency of conversion of the chip radiation into luminescence is achieved, which is comparable to that available in commercial phosphors. The maximum measured values of the position of the bands are from 553.5 to 559.6 nm. Brightness values range from 4,720 to 1,960 cd/m2. It was found that the main reason for the scatter in the characteristics of the luminescent properties of ceramics of yttrium-aluminum garnet, activated by cerium obtained by radiation assisted synthesis is the high rate of synthesis and, especially, the high rate of cooling of the samples.

Cross-section measurements of the Dy156(n,2n)Dy155 reaction at neutron energies higher than 17 MeV

In the present work the cross section of the $^{156}\mathrm{Dy}(n,2n)^{155}\mathrm{Dy}$ reaction (${E}_{\mathrm{th}}=9.51$ MeV) was measured at neutron beam energies above 17 MeV: 17.1, 18.1, and 19.0 MeV. The irradiations were performed at the 5.5-MV tandem accelerator of the Institute of Nuclear and Particle Physics at N.C.S.R. ``Demokritos'', where quasi-monoenergetic neutron beams were produced via the $^{3}\mathrm{H}(d,n)^{4}\mathrm{He}$ reaction. The cross-section measurements were performed by means of the activation technique relative to the $^{27}\mathrm{Al}(n,\ensuremath{\alpha})^{24}\mathrm{Na}$ reference reaction. Within the present work the experimental study is framed by theoretical calculations performed via the talys code (version 1.95).

Current and Future Technologies of the CNAO Dose Delivery System

The aim of this paper is to review the Dose Delivery System (DDS), developed by the National Center for Oncological Hadrontherapy (CNAO), Pavia, Italy, in collaboration with a group at the National Institute of Nuclear Physics (INFN) of Turin, Italy. The DDS controls and monitors the delivery of clinical ion beams.

Development of Ultra-Low-Resistance Splicing of Nb3Sn and NbTi Superconducting Wires

During the last decade, Budker Institute of Nuclear Physics (BINP) manufactured nine multipole superconducting wigglers on the basis of NbTi superconductor. These wigglers are operating at various synchrotron radiation centers worldwide. High magnet parameters were achieved due to using NbTi wire of high NbTi/Cu ratio, up to a factor of two, and by grading the current density in the coils. So, further increase in the magnet parameters is limited by the properties of NbTi conductor. Another important feature of the BINP wigglers is the magnet design, with superconducting coils manufactured separately and connected with a splicing resistance of well below 0.1 nΩ at an operating current of about 1 kA. That yields significant decrease in the heat load on cryocoolers because the total amount of splicings in one wiggler exceeds 200. The existing demand in superconducting wigglers and undulators for higher magnet parameters can be realized by using Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn wire. The ultimate aim of the on-going work at BINP is to make an Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn superconducting wiggler with separate coils, the terminals of which will be connected by NbTi wires with low splicing resistance, below 0.1 nΩ. During assembling of such a wiggler, these coils will be connected via NbTi terminals by the technology available at BINP. This article reports on first results of testing five samples of Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn-NbTi wire splicing. The experimental setup is described. The samples are two-turn loops made of Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn and NbTi wires. The samples were charged by currents of up to 500 A, and the resistance of these superconducting wire connections was evaluated from the current decay using a Hall sensor. All samples have demonstrated very low resistance, estimated as several Ohm.

JASPER: a software for quantum chromodynamics Dyson-Schwinger equation numerical calculation

The JASPER program is the first part of the high-performance computing information system for estimate some elementary particle properties, developing at Petersburg Nuclear Physics Institute. The JASPER is an implementation of the Dyson-Schwinger equation numerical solution for simple dressed quark propagator calculation in rainbow approximation. The Dyson-Schwinger equation solution with the Marice-Tandy Ansatz is one of several phenomenological approaches to obtain quantitative results in quantum chromodynamics (QCD) within strong coupling regime. The JASPER program is programmed in the C++ language and uses the numerical algorithms from the GNU Scientific Library (GSL). The numerical results for dynamical quark mass in complex Euclidean space were obtained. This result will be employed to study the hadron spectrum with the Bethe-Salpeter equation approach.

Evaluation of depth-dose profiles in a water phantom at the BNCT facility at BINP

In this study, we present depth-dose profiles measured with a water phantom at the boron neutron-capture therapy (BNCT) facility at Budker Institute of Nuclear Physics (BINP). The presented results demonstrate that the proposed design of radiation detector with an optical fiber readout, which includes three different sensors (the first based on a plastic scintillator enriched with boron, the second based on a simple plastic scintillator, and the third having no scintillator at all), enables measurement of neutron flux, as well as estimations of the dose induced by gamma rays. The results of simulations with the GEANT4 package demonstrated good agreement with the experimental data and can be used for further system improvement.

Development of high-voltage negative ion based neutral beam injector for fusion devices

A prototype of a powerful high-voltage neutral beam injector, based on acceleration of negative hydrogen ions and their neutralization, is under development at Budker Institute of Nuclear Physics (BINP). The design of the BINP high-voltage injector includes several innovative components, important for injector operation stability and overall efficiency. It includes a multi-aperture long-pulse surface-plasma negative ion source with thermostabilized grid, ithe magnetic system with concaved field lines in the ion-optic system (IOS) and the distributed cesium deposition system. The injector scheme incorporates a wide-aperture low-energy beam transport (LEBT) section, plasma target for negative ionneutralization, and recuperators of non-neutralized ions. Several test stands were constructed at BINP for injector component studies. This paper describes the results of experiments on negative ion beam production, transport through LEBT, ion acceleration to energy up to 240 keV and transport through the high voltage beam transport (HEBT) section to the distance ∼10 m from the source. The parameters of the transported beam, which were measured at several points along the beam line and at the beam dump calorimeter, are presented. The beam transport efficiency as a function of various ion source, LEBT and HEBT parameters is measured and compared with the calculated values. The results dof plasma neutralization target study are presented as well.

Radiobiological Outcomes, Microdosimetric Evaluations and Monte Carlo Predictions in Eye Proton Therapy

CATANA (Centro di AdroTerapia ed Applicazioni Nucleari Avanzate) was the first Italian protontherapy facility dedicated to the treatment of ocular neoplastic pathologies. It is in operation at the LNS Laboratories of the Italian Institute for Nuclear Physics (INFN-LNS) and to date, 500 patients have been successfully treated. Even though proton therapy has demonstrated success in clinical settings, there is still a need for more accurate models because they are crucial for the estimation of clinically relevant RBE values. Since RBE can vary depending on several physical and biological parameters, there is a clear need for more experimental data to generate predictions. Establishing a database of cell survival experiments is therefore useful to accurately predict the effects of irradiations on both cancerous and normal tissue. The main aim of this work was to compare RBE values obtained from in-vitro experimental data with predictions made by the LEM II (Local Effect Model), Monte Carlo approaches, and semi-empirical models based on LET experimental measurements. For this purpose, the 92.1 uveal melanoma and ARPE-19 cells derived from normal retinal pigmented epithelium were selected and irradiated in the middle of clinical SOBP of the CATANA proton therapy facility. The remarkable results show the potentiality of using microdosimetric spectrum, Monte Carlo simulations and LEM model to predict not only the RBE but also the survival curves.

Metastable states of Si− observed in a cryogenic storage ring

We have used the Cryogenic Storage Ring (CSR) at the Max Planck Institute for Nuclear Physics to study long-lived metastable states of the silicon anion. A ${\mathrm{Si}}^{\ensuremath{-}}$ beam of 58 keV kinetic energy was stored in the ultrahigh cryogenic vacuum of the CSR, employing only electrostatic deflection elements. We used laser systems at various wavelengths to infer information on the decay of the metastable anionic states by selective photodetachment. Our results give evidence of an excited anionic state for which we determine the extremely long lower lifetime limit of 5.7 h at 90% confidence level, consistent with theoretical predictions for the $^{2}D$ term. Furthermore, we find an average lifetime of $\ensuremath{\tau}=(22.2\ifmmode\pm\else\textpm\fi{}2.5)$ s for the weakly bound $^{2}P$ states, employing coincidence counting with a pulsed nanosecond laser at 2.45 $\ensuremath{\mu}\mathrm{m}$. Using a laser depletion technique, we produce a pure ground term $^{4}S_{3/2}\phantom{\rule{4pt}{0ex}}{\mathrm{Si}}^{\ensuremath{-}}$ beam, and we quantify the fraction of ions in metastable states in our initial ion sample. We combine our experimental efforts with state-of-the-art multiconfiguration Dirac-Hartree-Fock calculations for the radiative lifetimes of all metastable levels of ${\mathrm{Si}}^{\ensuremath{-}}$. We find these calculations to be in excellent agreement with our measurements and to improve previous efforts considerably.

The Performance of LiF:Mg-Ti for Proton Dosimetry within the Framework of the MoVe IT Project

Proton therapy represents a technologically advanced method for delivery of radiation treatments to tumors. The determination of the biological effectiveness is one of the objectives of the MoVe IT (Modeling and Verification for Ion Beam Treatment Planning) project of the National Institute for Nuclear Physics (INFN) CSN5. The aim of the present work, which is part of the project, was to evaluate the performance of the thermoluminescent dosimeters (TLDs-100) for dose verification in the proton beam line. Four irradiation experiments were performed in the experimental room at the Trento Proton Therapy Center, where a 150 MeV monoenergetic proton beam is available. A total of 80 TLDs were used. The TLDs were arranged in one or two rows and accommodated in a specially designed water-equivalent phantom. In the experimental setup, the beam enters orthogonally to the dosimeters and is distributed along the proton beam profile, while the irradiation delivers doses of 0.8 Gy or 1.5 Gy in the Bragg peak. For each irradiation stage, the depth–dose curve was determined by the TLD readings. The results showed the good performance of the TLDs-100, proving their reliability for dose recordings in future radiobiological experiments planned within the MoVe IT context.

Emittance Variation of a High-Current Relativistic Electron Beam in a Bend Magnet

The article presents the investigation results on the main angular divergence sources of a high-current relativistic electron beam when it passes through a real 12° bend magnet of the transport system in the linear induction accelerator (LIA), being developed by collaboration of Budker Institute of Nuclear Physics (BINP), Novosibirsk, Russia, and Russian Federal Nuclear Center—Zababakhin All-Russia Research Institute of Technical Physics (RFNC-VNIITF). The main results of the work are the calculated trajectories of the beam electrons, the shape of its cross section, as well as the change in the normalized emittance of the beam as it passes through the region of the bend magnet. It was shown that at typical beam parameters—electron energy of 20 MeV, beam current of 2 kA, and beam radius of 2 cm—the emittance of a high-current relativistic electron beam with uniform current and charge densities after the bend element is determined mostly by the magnet aberrations and much less by the beam self-fields. Optimization of the dipole magnet geometry made it possible to achieve a substantial decrease in the beam emittance with geometric expansion of the magnet in the median plane of the beam.

The Measurement of the Neutron Yield of the 7Li(p,n)7Be Reaction in Lithium Targets

Simple SummaryA compact neutron source has been proposed and created at the Budker Institute of Nuclear Physics in Novosibirsk, Russia. The source comprises an original design tandem accelerator, solid lithium target, and a neutron beam shaping assembly. The neutron source is capable of producing the high neutron flux for boron neutron capture therapy (BNCT). Currently, the BNCT technique has entered into clinical practice in the world: two clinics began treating patients, and four more BNCT clinics are ready to start operating. The neutron source proposed at the Budker Institute served as a prototype for a facility created for a clinic in Xiamen (China). It is planned to equip the National Medical Research Center of Oncology (Moscow, Russia) and National Oncological Hadron Therapy Center (Pavia, Italy) with the same neutron sources. Due to the impending use of an accelerator neutron source for treating patients, the validation of the neutron yield of the 7Li(p,n)7Be reaction in lithium metal targets is required. The theoretical neutron yield has not been evaluated experimentally so far.A compact accelerator-based neutron source has been proposed and created at the Budker Institute of Nuclear Physics in Novosibirsk, Russia. An original design tandem accelerator is used to provide a proton beam. The neutron flux is generated as a result of the 7Li(p,n)7Be threshold reaction using the solid lithium target. A beam shaping assembly is applied to convert this flux into a beam of epithermal neutrons with characteristics suitable for BNCT. The BNCT technique is being tested in in vitro and in vivo studies, and dosimetry methods are being developed. Currently, the BNCT technique has entered into clinical practice in the world: after successful clinical trials, two clinics in Japan began treating patients, and four more BNCT clinics are ready to start operating. The neutron source proposed at the Budker Institute of Nuclear Physics served as a prototype for a facility created for a clinic in Xiamen (China). It is planned to equip the National Medical Research Center of Oncology (Moscow, Russia) and National Oncological Hadron Therapy Center (Pavia, Italy) with the same neutron sources. Due to the impending use of an accelerator neutron source for treating patients, the validation of the neutron yield of the 7Li(p,n)7Be reaction in lithium metal targets is required. The theoretical neutron yield has not been evaluated experimentally so far.

Decision support system for the proton therapy implementation

The authors propose the method that is intended for automating patient treatment technological process in a proton therapy center and based on a decision support system. The developed information system provides the implementation of the proton therapy protocols. The technological process of the proton therapy is strictly regulated. It includes not only the process of therapy itself (irradiation of the patient), but also the preliminary stages of treatment, as well as the stages following the irradiation process. Proton therapy centers use information systems, such as radiological and hospital information systems (oncology information systems), that provide information support for separate stages. At the moment, there is no system that controls the entire technological process in a proton therapy center. The proposed system ensures that the operator complies with the protocol of the treatment’s stage and supports the entire technological process of the proton therapy. The system sets the schedule of stages, order and possibility of their parallel implementation, determines the conditions for allowing the start of the stage, provides the subsystems with the protocol of the stage and necessary data of protocol to manage the stage by the operator, and also records the results of the completed stage. The system is built on the “client-server” technology. The server has a software part (that implements the concept the server) and a database. For each operator workstation that manages the stage, the client software of the system is additionally installed. The paper describes an approach to creating a decision support system for the personnel of a proton therapy center. Such a system provides the correct implementation and sequence of the proton therapy stages. The system has been included in the project of the Research Proton Therapy Center for Ophthalmic Oncology at Saint Petersburg Nuclear Physics Institute of National Research Center “Kurchatov Institute”. The necessary information is transmitted from the system to the proton therapy center equipment via radiological and hospital information systems using standard protocols. It allows the solution to serve as a part of any automated control system of a radiation therapy center (not only for proton therapy).