Institute Of Nuclear Sciences Research Articles

Intercomparison of neutron personal dose equivalent measured by thermoluminescence dosimeters

An intercomparison of neutron personal dose equivalent measured by the Harshaw thermoluminescence neutron dosimeters (TLDs) between the National Institute of Metrology of China (NIM) and the Institute for Nuclear Science and Technology of Vietnam (INST) was performed. Three sets of TLDs (each set consisting of five TLDs) were prepared for each laboratory. Each set was then irradiated to the corresponding same nominal standard value of neutron personal dose equivalent, Hp(10)n−stdi, of 1.0, 2.0, and 3.0 mSv, respectively at these two laboratories. The irradiated TLDs were then read-out at the INST using the Harshaw 4500-type TLD reader to obtain neutron personal dose equivalents at the NIM, Hp(10)n−NIMi and at the INST, Hp(10)n−INSTi, which are corresponding to different values of Hp(10)n−stdi. The TLDs’ responses to different scattered components of neutrons in these two fields are also discussed. Comparisons between the corresponding pair values of Hp(10)n−NIMi and Hp(10)n−INSTi show good agreements within 10% with the standard uncertainty of 12.5% (k = 1). The measured values of Hp(10)n−NIMi and Hp(10)n−INSTi are satisfied the Trumpet curve criteria. This implies that the TLDs can be used for safety assessment of occupational neutron personal dose equivalents. This intercomparison result also confirms the capabilities of these two laboratories (i.e., NIM, INST) on deliveries of neutron personal dose equivalent standard values for calibrations.

Archaeometry in Serbia: Where we are and where we should go next?

The paper presents a short history of archaeometry investigations in Serbia, from the first published work in 1932 until today. It then describes the most important laboratories and institutions that perform archaeometry investigations in Serbia today, their teams, equipment, projects, and cooperation: Institute for the Protection of Cultural Monuments of Serbia, Vinča Institute of Nuclear Sciences, Faculty of Physical Chemistry, National Museum of Serbia, Institute of Archaeology, the Heritage Lab, Gallery of Matica Srpska Novi Sad, and City Museum of Subotica. The paper describes plans for the future and proposes forming of Serbian Society for Archaeometry with several goals: to further interconnect research disciplines; to facilitate better use and purchase of equipment, to establish a dedicated laboratory for archaeometry; to introduce archaeometry study programs at different levels of teaching; to introduce archaeometry into scientific plans of Serbia; to start a domestic archaeometry journal, and to promote the awareness of the potentials and benefits of archaeometry to institutions dealing with cultural heritage and to the general public.

Establishment of Neutron Reference Fields in Vietnam: A Review

This paper summarizes the characterizations of neutron reference fields using radionuclide sources at the Institute for Nuclear Science and Technology (INST), Hanoi, Vietnam for the purposes of radiation protection and calibrations. The dosimetric quantities of spectral neutron fluence rates and neutron ambient dose equivalent rates have been calculated and presented using the Monte Carlo N-Particle transport code, version 5 (MCNP5) and Bonner sphere spectrometer (BSS) measurements in the combination with MAXED unfolding code. The characterizations of neutron reference fields have been done, complying with the ISO 8529 and 12789 series. The results confirm the neutron calibration capability at the INST in order to fulfill the domestic calibration demands of neutron ambient dose equivalent rate meters.

Characteristics of Simulated Workplace Neutron Standard Fields

This paper presents the development of simulated workplace neutron standard fields at the Institute for Nuclear Science and Technology with the 241Am-Be source moderated by polyethylene spheres with diameters of 15 cm and 30 cm. The characterization of the standard fields (in terms of neutron fluence rates and neutron ambient dose equivalent rates) was performed using Bonner sphere spectrometer system together with MAXED and FRUIT unfolding codes. The related quantities such as neutron dose equivalent-averaged energies and fluence-to-ambient dose equivalent conversion coefficients were also determined. The discrepancies of values are satisfied the standard uncertainty criteria as recommended by the International Standard Organization 12789 series. It implies that the simulated workplace neutron standard fields can be applied in the practical works for calibration purposes.

Optimization of the S-band side-coupled cavities for proton acceleration

The proton beam with energy around 100 MeV has seen wide applications in modern scientific research and in various fields. However, proton sources in China fall short for meeting experimental needs owing to the vast size and expensive traditional proton accelerators. The Institute of Nuclear Science and Technology of Sichuan University proposed to build a 3 GHz side-coupled cavity linac (SCL) for re-accelerating a 26 MeV proton beam extracted from a CS-30 cyclotron to 120 MeV. We carried out investigations into several vital factors of S-band SCL for proton acceleration, such as optimization of SCL cavity geometry, end cell tuning, and bridge coupler design. Results demonstrated that the effective shunt impedance per unit length ranged from 22.5 to 59.8 MΩ/m throughout the acceleration process, and the acceleration gradient changed from 11.5 to 15.7 MV/m when the maximum surface electric field was equivalent to Kilpatrick electric field. We obtained equivalent circuit parameters of the biperiodic structures and applied them to the end cell tuning; results of the theoretical analysis agreed well with the 3D simulation. We designed and optimized a bridge coupler based on the previously obtained biperiodic structure parameters, and the field distribution un-uniformness was < 1.5% for a two-tank module. The radio frequency power distribution system of the linac was obtained based on the preliminary beam dynamics design.

Scientific activity of Prof. Naim Afgan at Laboratory for Thermal Engineering and Energy, Institute for Nuclear Sciences - Vinca

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Influence of the Charge State of Xenon Ions on the Depth Distribution Profile Upon Implantation into Silicon

Experimental depth distributions of the concentration of implanted xenon ions depending on their charge state and irradiation energy are presented. Xenon ions in charge states q = 1–20 and energies in the range from 50 to 400 keV are incorporated into single-crystal silicon. Irradiation is performed in the direction not coinciding with the crystallographic axes of the crystal to avoid the channeling effect. The ion fluence varies in the range of 5 × (1014–1015) ion/cm2. The irradiation by singly charged ions and investigation of the samples by Rutherford backscattering spectroscopy is performed using an HVEE acceleration complex at Moscow State University. Multiply charged ions are implanted using a FAMA acceleration complex at the Vinca Institute of Nuclear Sciences. The depth distribution profiles of the incorporated ions are found using Rutherford backscattering spectroscopy. Experimental results are correlated with computer calculations. It is shown that the average projective path of multiply charged ions in most cases is shorter when compared with the average projected path of singly charged ions and the results of computer modeling.

SOIL AND RADIONUCLIDES OF EASTERN HERZEGOVINA

&amp;lt;p&amp;gt;Soil is one of the most important natural resources. Measurement of natural radioactivity in soil is very important to determine the amount of change of the natural background activity with time as a result of any radioactivity release.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Coal mine and thermal power plant in Gacko field is a very important industrial facility. The content of radionuclides of the soil was examined at Gacko area, slag, ash and mullock dumps in thethermal power plant Gacko and soils of dumps in the process of re-cultivation. The gamma &amp;ndash; spectrometric measurements were done in the Institute of Nuclear Sciences &amp;ldquo;Vinča&amp;rdquo; in Belgrade.Soil samples were collected in 2010/2014 at more locations in eastern part of Republic of Srpska. After removing the stones and vegetation, all soil samples for Gama spectrometric measurements dried up to 1050C, sieved, placed in the plastic 500 mL Marinelli beakers and left for four weeks to reach radioactive equilibrium.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Given that there are no specific regulations in the Republic of Srpska, the concentration of natural and produced radionuclides in samples from the working and living environment of thermal power plants, comparison with literature data from the region and the world is one way of evaluating the impact of the plant's operation on the soils.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;The results point to the necessity of regular monitoring of radioactivity in eastern Herzegovina in order to assess the impact of the technologically increased natural radioactivity&amp;lt;/p&amp;gt;

Review of the investigations of pulverized coal combustion processes in large power plants in laboratory for thermal engineering and energy: Part A

The paper presents an overview of the results of the investigations of the processes that take place in pulverized coal combustion boilers and power plants which, in a longer period of time, were realized in the Laboratory for Thermal Engineering and Energy of the "Vinca" Institute of Nuclear Sciences. The presented results were published in numerous studies realized for different users, Ph. D., M. Sc., and specialist thesis, in international and domestic scientific journals and monographs, presented at numerous international and domestic scientific meetings, etc. The main goal of the paper is to chronologically present the results of domestic research that at one time were at an enviable international level, with concrete practical applications for domestic users. This is especially important to contrast the present situation when domestic research in this area is scarce and when the energy sector relies practically only on imported technologies and foreign consultancy. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III42011, Grant no. III42010, Grant no. TR33018 and Grant no. TR33042] &lt;br&gt;&lt;br&gt;&lt;font color="red"&gt;&lt;b&gt; This article has been corrected. Link to the correction &lt;u&gt;&lt;a href="http://dx.doi.org/10.2298/TSCI200127032E"&gt;10.2298/TSCI200127032E&lt;/a&gt;&lt;u&gt;&lt;/b&gt;&lt;/font&gt;

Review of the investigations of pulverized coal combustion processes in large power plants in laboratory for thermal engineering and energy: Part B

Paper presents short review of research problems, applied methods for solving problems and main results obtained by the researchers in Laboratory for Thermal Engineering and Energy (LTE) of the "Vinca" Institute of Nuclear Sciences, Belgrade, Serbia dealing with pulverized coal combustion processes and technologies for reduction of pollutions problems at thermal power plants in a period since 2000. The presented results were published in numerous studies realized for different users, Ph. D., Masters, and Specialist thesis, in international and domestic scientific journals and monographs, presented at numerous international and domestic scientific conferences, etc. Presented research projects and results of applied research projects realized at pulverized coal combustion thermal power plants clearly show that LTE team was involved in key activities of rehabilitation and modernization, including implementation of best available technologies for pollution reduction at thermal power plants, in the region of South East Europe.

Fizičko-hemijske analize strukturalnih slojeva kod slika na drvenom i platnenom nosiocu - na primerima prestonih ikona iz Saborne crkve u Požarevcu

Iconostasis from Orthodox cathedral in Požarevac were painted at the end of 19th century. Today, after more than one hundred years, there is a need for restoration of these icons from altar barrier that were painted by Nikola Marković. Restoration was done in the conservation ateliers of the Academy of Serbian Orthodox Church for Fine Arts and Conservation. In order to get detailed insight of painting materials and paints used to make these icons, few instrumental analysis were done. Under research Visible, IR and UV images were photographed at the Central Conservation Institute in Belgrade. At the Institute for Nuclear Sciences "Vinča" EDXRF and FTIR spectroscopy instrumental analyses were performed on the icons of the Virgin on the throne, the Last Supper and St. Stefan First King of Serbia. The EDXRF analyses revealed the chemical composition of the pigments used at the analysed points, while the FTIR analyses revealed the composition of the binder. All analysis in this scientific work was done as master thesis.

Влияние зарядового состояния ионов ксенона на профиль распределения по глубине при имплантации в кремний

AbstractExperimental depth distributions of the concentration of implanted xenon ions depending on their charge state and irradiation energy are presented. Xenon ions in charge states q = 1–20 and energies in the range from 50 to 400 keV are incorporated into single-crystal silicon. Irradiation is performed in the direction not coinciding with the crystallographic axes of the crystal to avoid the channeling effect. The ion fluence varies in the range of 5 × (10^14–10^15) ion/cm^2. The irradiation by singly charged ions and investigation of the samples by Rutherford backscattering spectroscopy is performed using an HVEE acceleration complex at Moscow State University. Multiply charged ions are implanted using a FAMA acceleration complex at the Vinća Institute of Nuclear Sciences. The depth distribution profiles of the incorporated ions are found using Rutherford backscattering spectroscopy. Experimental results are correlated with computer calculations. It is shown that the average projective path of multiply charged ions in most cases is shorter when compared with the average projected path of singly charged ions and the results of computer modeling.

65 DQPRM trainees welcome in EAP: APHM experience

Introduction DQPRM (Qualification diploma in Radiological and Medical Physics) students have theoretical courses at INSTN (National Institute of Nuclear Sciences and Technologies) for 6 months and complete their training with a 22-months hospital internship in an institution named Principal Home (EAP), in order to learn and validate the skills required for their future career of medical physicist. The internship duration is divided into different branches of activity that are mainly radiotherapy, radiology and nuclear medicine. Trainees are supervised by experimented medical physicists in each domain. Methods Before their arrival, students are invited to contact the person in charge of their reception at the EAP, and organize a first visit of the center. Upon arrival, after having completed the administrative steps (medical approval for work, blouses, meal card, computer access, …), trainees are invited to participate to a full meeting, letting them meet the whole physics team. At this time, the welcome book, previously sent, is detailed. It describes the Physics unit, organization of as well as the radiotherapy and medical imaging departments. During this meeting, the organization of the internship is explained and an annual planning is defined on the different parts. This organization allows a fair time distribution between participation in clinical routine and the completion of activity sheets supervised by different members of the team. This assignment allows optimal preparation and completion of the activities with the designated referent. Each supervisor sets with the trainees, the moment of the realization and validation of the skills. The students prepare the measurements to be done and the working method, and have the referent process validated. The measurements are made with or under supervision of the supervisor. This will validate the level of mastery of skills (not acquired, being acquired or acquired). Trainees also participate in the clinical routine. It’s important that they integrate perfectly the routine organization of the service (for example to participate in the morning staff, to integrate the planning of quality assurance of linear accelerators, to carry out pre-treatment checks, to carry out controls in medicine nuclear or estimate fetal exposure in radiology). This is a key step in learning the profession of medical physicists. Conclusions Effective and respectful management of DQPRMs is essential for the training in the field to be optimal, both humanly and scientifically. It’s meaningful that the two years of internship, which for many, are their first steps in medical physics, become a success.

64 Management of the medical physics students in internship: Feedback of Centre Eugène Marquis (Regional Cancer Center of Rennes/France)

Introduction The Regional Cancer Center of Rennes (Centre Eugene Marquis, CEM) is one of 31 French institutions hosting students preparing the final diploma of medical physicist (DQPRM) for 22-month internship in the three area of medical physics: radiotherapy (RT), nuclear medicine (NM) and radiology (RX). The CEM is accredited by the National Institute for Nuclear Science and Technology (INSTN) to train two students in the first year and two students in the second year. The objective is to share the feedback from the CEM on the management of students during these 22 months of internship. Methods During the first week of the internship, a meeting of the entire physics team is organized to introduce the DQPRM students to all the members of the team, to plan the weeks dedicated to each field and to define the reference physicist for each activity to be acquired. During this meeting the general organization of the team and the specific organization for the DQPRM students are presented. The scientific work of the second year is defined among the list of projects of the team in dialogue between the student and the referent physicist of the training center. The study is managed by a senior physicist specialized in the area of the work. Some parts of the document presenting the functional schedule of the team are dedicated to the DQPRM students to reveal clearly their participation in the clinical activities. The students are invited to all meetings in which the medical physicists participate. A bi-monthly point of 30 min is organized between the students and the referent physicist of the training center. Results During the first month, the students have to define with the referent physicist for every activity the annual organization to acquire the expected skills. Regarding to functional schedule of 2017, the students of 1st year spent 49% of days in RT, 20% in NM and 10 in RX. These percentage were 51%, 16% and 11% respectively for the students of 2nd year. A delegation of some functional tasks are possible after validation of specific skills base. Depending of the subject of the scientific work performed during 2nd year of training, writing of the report is encouraged in English in order to facilitate the submission in an international journal. Conclusions Concurrently to the acquisition of basic skills of the medical physicist, the objective of the 22 months of internship is to transform the DQPRM students in a young professional in a progressive and supervised way by teaching them the teamwork, the empowerment and time management thanks to clinical activities and projects.

The k0-standardization of NAA: germs, launch, breakthrough—on stage and in the wings

An account is given of the historical development of the k0-standardization of neutron activation analysis: starting from its first germs, logically leading to its launch and subsequently to its breakthrough. Emphasis is put on the pioneering role, both in the wings and on stage, of the two key laboratories involved in this process, namely the nuclear-analytical departments of the KFKI (Central Research Institute for Physics, Budapest, Hungary) and the INW (Institute for Nuclear Sciences, Gent, Belgium).

Performance of Tc-99m Generators in Terms of Molybdenum Contents Measured in NORIN Nawabshah, Pakistan (5 years’ Experience)

Technetium-99m is extensively used radiopharmaceutical in nuclear medicine centres throughout the world because of its optimum half-life and photon energy. 99mTc is obtained from 99mTc-99Mo generator. 99Mo contents may appear in 99mTc elutes due to certain reasons. These contents are needed to be checked before injecting it to the patient. In Pakistan, these generators are manufactured in Pakistan Institute of Nuclear Science and Technology (PINSTECH), Islamabad, who names its generators as PAKGEN. 99mTc is eluted on site from generator and used with pharmaceutical kit. Eluted 99mTc may contain some impurities which need to be contained within predefined allowed limits. One of the impurities is molybdenum. For molybdenum, there are two protocols being used worldwide. European pharmacopeia declares the allowed activity of Molly in 99mTc elute to be less than 1 µCi of 99Mo for every mCi of 99mTc, while American pharmacopeia defines it to be less than 0.15 µCi/mCi. PINSTECH is using European standards for its PAKGEN generators. NORIN is using 99mTc-99Mo generators since 2012, purchased from PINSTECH Islamabad. A total of 216 generators were purchased till date. Current study is an assessment of Molly assay tests performed on the first elution of every generators before its administration to patients for diagnostic procedures. Results of these tests are compared with both European and American pharmacopeia standards and found out to be well within both limits. Only 1.4% of total 216 generators were found to be out of the limit of 0.15 µCi/mCi (being practiced in our medical centre), while no one exceeded the limit of 1 µCi/mCi (being implemented by the manufacturer of generators). It is concluded that PAKGEN generators are reliable source of technetium-99m in terms of molybdenum contents.

Semiempirical Efficiency Calibration in Semiconductor HPGe Gamma-Ray Spectroscopy

One of the main problems in quantitative gamma-ray spectroscopy is the determination of detection efficiency, for different energies, source-detector geometries, and composition of samples or sources. There are, in principle, three approaches to this issue: experimental, numerical, and semiempirical. Semiempirical approach is based on the calculation of the efficiency for the measured sample on the basis of an experimental efficiency measured on the same detector, but with a calibration source that can be of different size, geometry, density, or composition—the so-called efficiency transfer. The aim of this paper is to analyze the semiempirical approach, using EFFTRAN and MEFFTRAN software as a typical example. These software were used in the Department of Radiation and Environmental Protection, Vinča Institute of Nuclear Sciences, on three HPGe detectors. The results were compared to the experimentally obtained efficiency, and further validation is performed by measuring reference materials issued within the framework of several interlaboratory intercomparisons. The analysis of the results showed that the efficiency transfer produces good results with the discrepancies within the limits of the measurement uncertainty. Also, for intercomparison measurement, utest criterion for the trueness of the result was applied showing that the majority of the obtained results were acceptable. Some difficulties were identified, and the ways to overcome them were discussed.

Upgrading the ECR ion source within FAMA

Recent upgrading of the Facility for Modification and Analysis of Materials with Ion Beams - FAMA, in the Laboratory of Physics of the Vinca Institute of Nuclear Sciences, included the modernization of its electron cyclotron resonance ion source. Since the old ion source was being extensively used for more than 15 years for production of multiply charged ions from gases and solid substances, its complete reconstruction was needed. The main goal was to reconstruct its plasma and injection chambers and magnetic structure, and thus intensify the production of multiply charged ions. Also, it was decided to refurbish its major subsystems - the vacuum system, the microwave system, the gas inlet system, the solid substance inlet system, and the control system. All these improvements have resulted in a substantial increase of ion beam currents, especially in the case of high charge states, with the operation of the ion source proven to be stable and reproducible.

Design of a side coupled standing wave accelerating tube for NSTRI e-Linac

The design and construction of a 6 MeV electron linear accelerator (e-Linac) was defined in the Institute of Nuclear Science and Technology (NSTRI) for cargo inspection and medical applications. For this accelerator, a side coupled standing wave tube resonant at a frequency of 2998.5 MHZ in π/2 mode was selected. In this article, the authors provide a step-by-step explanation of the process of the design for this tube. The design and simulation of the accelerating and coupling cavities were carried out in five steps; (1) separate design of the accelerating and coupling cavities, (2) design of the coupling aperture between the cavities, (3) design of the entire structure for resonance at the nominal frequency, (4) design of the buncher, and (5) design of the power coupling port. At all design stages, in addition to finding the dimensions of the cavity, the impact of construction tolerances and simulation errors on the electromagnetic parameters were investigated. The values obtained for the coupling coefficient, coupling constant, quality factor and capture efficiency are 2.11, 0.011, 16203 and 36%, respectively. The results of beam dynamics study of the simulated tube in ASTRA have yielded a value of 5.14 π-mm-mrad for the horizontal emittance, 5.06 π-mm-mrad for the vertical emittance, 1.17 mm for the horizontal beam size, 1.16 mm for the vertical beam size and 1090 keV for the energy spread of the output beam.

Characterization of an ²⁴¹Am-Be neutron irradiation facility at Institute for Nuclear Science and Technology

An automated panoramic irradiator with a 241Am-Be neutron source of 5 Ci is installed in a bunker-type medium room at the Institute for Nuclear Science and Technology (INST) for calibration of neutron devices. Bonner Sphere Spectrometer (BSS) formed by 6 spheres plus bare detector, with cylindrical, almost point like, 6LiI(Eu) scintillator and 2 different spectral unfolding FRUIT and BUNKIUT codes are used to characterize the neutron field in different measurement points along the irradiation bench. The neutron field is also simulated by MCNP5 software and compared with measurements performed by the BSS. The paper shows the main results obtained in terms of neutron spectra at fixed distances from the source as well as their neutron fluence rate (total and direct) and ambient dose equivalent rate. These values measured by the BSS with two unfolding FRUIT and BUNKIUT codes are in good agreement with that of simulated by MCNP5 within 10%.