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One of the most useful applications of MOSFET semiconductor components has been introduced to improve the gamma or electron radiation detection system. In many practical cases it is not easy to carry out experimental tests of semiconductor devices in radiation environment, so it is more convenient to perform the assessment of ionizing radiation interaction with semiconductor devices by using numerical methods based on Monte Carlo simulation techniques. A large number of previous studies have mainly focused on the study of MOSFET dosimeter response to gamma and X radiation fields. Therefore, this work will be focused on a new approach to the study radiation characteristics of the MOSFET dosimeter in fields of other types, such as field of high-energy electrons (4 MeV to 20 MeV). From the engineering point of view, it is important to consider the material that is used as a physical protection of the MOSFET dosimeter. So, it is important to investigate the energy dependence of MOSFET dosimeter to different shielding materials. For this purpose, special numerical experiments of electron transport within all layers of the elementary MOSFET structure will be performed. Shielding materials such as Kovar, Titanium Alloy with Aluminum and Niobium, Titanium Alloy with Zirconium and Niobium will be considered. The electron transport will be simulated with Monte Carlo method using the software package FOTELP-2K12. The distribution of deposited energy in all material zones of interest, as well as the absorbed dose in dosimeter sensitive zone of MOSFET structure will be determined by results obtained with numerical calculations. The physical shielding factor (PSF) for the MOSFET dosimeter, which can show the correlation between dosimeter energy dependence and shielding material in the field of electron beam radiation, will be determined within the paper. After comparing values of PSF for considered materials the recommendation for a lid material that serves as shielding for MOSFE

A mathematical model of the SVZ-100 lead slowing-down neutron spectrometer designed at the Institute for Nuclear Research, Russian Academy of Sciences (Moscow) is presented. The neutron spectra in the SVZ-100 measuring channels are calculated by the Monte Carlo method at different slowing-down times. The influence of the energy resolution of the spectrometer on the shape of the neutron cross sections is demonstrated. The developed model makes it possible to establish agreement between experimental data obtained using neutron spectrometers by different methods and with different resolutions and compare the results of measuring the neutron cross sections of thorium and transuranic elements using the SVZ-100 with recommended international databases.

Lead slowing-down (LSD) spectrometers have a low energy resolution (about 30%), but their luminosity is 10(3) to 10(4) times higher than that of time-of-flight (TOF) spectrometers. A high luminosity of LSD spectrometers makes it possible to use them to measure neutron cross section for samples of mass about several micrograms. These features specify a niche for the application of LSD spectrometers in measuring neutron cross sections for elements hardly available in macroscopic amounts-in particular, for actinides. A mathematical simulation of the parameters of SVZ-100 LSD spectrometer of the Institute for Nuclear Research (INR, Moscow) is performed in the present study on the basis of the MCNPX code. It is found that the moderation constant, which is the main parameter of LSD spectrometers, is highly sensitive to the size and shape of detecting volumes in calculations and, hence, to the real size of experimental channels of the LSD spectrometer. DOI: 10.1134/S1063778813030113

In recent years, an increasing number of research works have been addressed to the study of the characteristics and applications of MOSFET detectors in the field of nuclear industry, medical applications and space research. At a time when the stormy development of technology, a new type of solid state dosimeter, the MOSFET detector, has been introduced into the radiotherapy, primarily for in vivo patient dosimetry in electron-beam irradiation. One of the major goals of our work was the presentation of the shielding energy dependence factor which assesses the impact of the lid with different shielding materials to MOSFET response for different energies of electron-beam irradiation into range 4 MeV – 20 MeV. In doing so, the established Monte Carlo numerical method for analysis influence of the packaging to energy dependence, carried out prior to any experimental testing. The bare MOSFET is encapsulated in epoxy glue which mechanically protects the chip. To trace the influence of the lid is the one intended by the physical protection, on the other hand, it can also be used for the protection against radiation, is introduced that defines the shielding energy dependence factor (SDEF) for different electron energies and for different constructional materials of lid. Factor SDEF is defined as the ratio of values of the absorbed dose, which in fact means that it is equal to the energy deposited when the MOSFET is shielded with protection, and the MOSFET without a lid. When we know the energy dependence factor for SDEF MOSFET with and without armor can be carried out and the analysis of whether and to what extent the energy required compensating the electronic components. In order to use the Monte Carlo numerical methods in this paper, the appropriate geometry form of the MOSFET dosimeter was defined using the adequate software. The electron transport Monte Carlo code FOTELP-2K10 has been adopted to analyze the influence of the MOSFET package on its energy response. FOTELP

The most powerful feature of the Monte Carlo method is the possibility of simulating all individual particle interactions in three dimensions and performing numerical experiments with a preset error. These facts were the motivation behind the development of a general-purpose Monte Carlo SRNA program for proton transport simulation in technical systems described by standard geometrical forms (plane, sphere, cone, cylinder, cube). Some of the possible applications of the SRNA program are: (a) a general code for proton transport modeling, (b) design of accelerator-driven systems, (c) simulation of proton scattering and degrading shapes and composition, (d) research on proton detectors; and (e) radiation protection at accelerator installations. This wide range of possible applications of the program demands the development of various versions of SRNA-VOX codes for proton transport modeling in voxelized geometries and has, finally, resulted in the ISTAR package for the calculation of deposited energy distribution in patients on the basis of CT data in radiotherapy. All of the said codes are capable of using 3-D proton sources with an arbitrary energy spectrum in an interval of 100 keV to 250 MeV.

Radiation sensing MOSFETs have found numerous applications as detectors or device components in radiation fields used in nuclear industry, medical applications and space research. Monte Carlo simulations of MOSFET energy response to X-ray and gamma radiation for different packaging were performed. The photon transport Monte Carlo software FOTELP-2K10 has been adapted to obtain the energy deposited in MOSFET structure with microscopic dimensions. In this work the ratio between values of total energy deposited in the sensitive volume (thick SiO2 layer) for cases of MOSFET structure with and without package lid is presented. For this purpose is defined the shielding energy dependence factor (SDEF), and gave its value for kovar and Ti-24Al-11Nb and Ti-13Nb-13Zr alloys as lid materials.

This work presents a characterization of radiation absorption properties of silicon carbide (SiC) as semiconductor for the realization of detectors for X-rays. SiC detectors can potentially reach superior performance with respect to all the other semiconductors presently employed in hazardous environments in nuclear and space science and technology. Physics and numerical modeling of photons transport through SiC detector is incorporated in non-destructive Monte Carlo method for determining the energy deposited and dose distribution. The Monte Carlo code has been adopted for numerical simulations for different detector conditions and configurations. The X-ray characterization of new SiC structures originates the improving of design of these detector systems.

This work presents a characterization of radiation absorption properties of silicon carbide (SiC) as semiconductor for the realization of detectors for X-rays. SiC detectors can potentially reach superior performance with respect to all the other semiconductors presently employed in hazardous environments in nuclear and space science and technology. Physics and numerical modeling of photons transport through SiC detector is incorporated in non-destructive Monte Carlo method for determining the energy deposited and dose distribution. The Monte Carlo code has been adopted for numerical simulations for different detector conditions and configurations. The X-ray characterization of new SiC structures originates the improving of design of these detector systems.

Nuclear facilities as nuclear power stations, nuclear research reactors, particle accelerators and linear accelerator in medical institution using concrete in building construction. The different type materials of the aggregate as component of concrete were analyzed to provide radiation protection. The energy deposited the transmission factor and the mass attenuation coefficients in ordinary and barite concretes have been calculated with the photon transport Monte Carlo software. The numerical simulations results show that using barite as an aggregate in the concrete is one of the solutions for gamma ray shielding. Thereat, it is shown non-destructive method for determining the gamma radiation absorption characteristics of concrete.

The possibility of expressing the total particle and energy reflection coefficients of low-energy photons in the form of universal functions valid for different shielding materials is investigated in this paper. The analysis is based on the results of Monte Carlo simulations of photon reflection by using MCNP, FOTELP, and PENELOPE codes. The normal incidence of the narrow monoenergetic photon beam of the unit intensity and of initial energies from 20 keV up to 100 keV is considered, and particle and energy reflection coefficients from the plane homogenous targets of water, aluminum, and iron are determined and compared. The representations of albedo coefficients on the initial photon energy, on the probability of large-angle photon scattering, and on the mean number of photon scatterings are examined. It is found out that only the rescaled albedo coefficients dependent on the mean number of photon scatterings have the form of universal functions and these functions are determined by applying the least square method.

Titanium alloys have found numerous applications in space research, and nuclear industry and research. Since X-rays constitute an important part of the space radiation environment, numerical simulations of radiation absorption characteristics of titanium alloys were studied in this paper. The photon transport Monte Carlo software was used for determining the energy deposited in titanium samples. The numerical results show the pronounced dependence of radiation absorption properties of different combinations of components in alloy. The results obtained are encouraging in respect of optimization of structure of alloys regarding their required features in radiation shielding.

The use of diamond as material for X-ray detector is subject of investigation and practice in radiotherapy, space and material science and technology. This paper presents the results of application of Monte Carlo method for simulation of photon transport through diamond detector. The aim is restitution and demonstrating of numerical technique for characterization of electrical properties for different detector conditions and configurations. Monte Carlo code was adopted to determine the energy deposited and dose distribution in the structure of diamond detector. Our results show that the use of numerical simulations may be of essential help in design of diamond detector systems.

Titanium alloys have found numerous applications in space research, and nuclear industry and research. Since X-rays constitute an important part of the space radiation environment, numerical simulations of radiation absorption characteristics of titanium alloys were studied in this paper. The photon transport Monte Carlo software was used for determining the energy deposited in titanium samples. The numerical results show the pronounced dependence of radiation absorption properties of different combinations of components in alloy. The results obtained are encouraging in respect of optimization of structure of alloys regarding their required features in radiation shielding.

Radiation sensing MOSFETs (RADFETs) have found numerous applications in space research, as well as in nuclear technology and research, and radiotherapy. Since proton irradiation is an essential part of the space radiation environment, it is important to know RADFET proton response precisely. In this work a numerical simulation of RADFET proton response is performed. To this end the proton transport Monte Carlo software SRNA-2K5, developed by one of the authors, has been adapted to obtain the energy deposited in the RADFET structure and dose distribution within the microscopic dimensions of the dosimeter sensitive volume. Our results show that RADFET response to proton irradiation depends significantly of packaging configurations with kovar lid.

The dependence of reflected photons angular and energy distributions on parameter c - the probability for large-angle scattering - is treated in this paper. The simulation of photon reflection was performed by the FOTELP code for a normal incidence of photons into infinite slabs of common shielding materials, and for the photon initial energies of 20 keV up to 100 keV.

The use of semiconductor materials in radiation processing, radiation therapy and diagnostics, and detection of cosmic radiation motivated development of numerical methods for its radiological characterization. This paper presents the application of the Monte Carlo method using the FOTELP-2K4 code for radiological characterization of Metal Oxide Semiconductor Field Effect Transistor (MOSFET) dosimeter. The advantages of MOSFET dosimeters include small size, immediate readout, and ease of use for a wide photon energy range. In order to determine the dosimeter response accurately, distribution of the absorbed dose in the MOSFET structure has been investigated. Our results show that the absorbed dose distribution calculated by the presented simulation model compares well with the published data.

The application of MOSFETs as detectors or device components in pulse power technique requires an investigation of their characteristics in radiation fields. Computing possibilities of the renowned programs FOTELP and PENELOPE for determining the energy deposited in MOISFET structure and dose distribution within microscopic dimensions of the dosimeter sensitive volume were presented in this paper. Based on the obtained results, qualitative conclusions were drawn about the values of energy deposited in different material zones having various dimensions. The difference between the two codes used for calculations in materials physics and semiconductor technics, basically originates from the different physical models for numerical simulation of photon, positron, and electron transport through various materials.

The application of MOSFETs as detectors or device components in pulse power technique requires an investigation of their characteristics in radiation fields. Computing possibilities of the renowned programs FOTELP and PENELOPE for determining the energy deposited in MOISFET structure and dose distribution within microscopic dimensions of the dosimeter sensitive volume were presented in this paper. Based on the obtained results, qualitative conclusions were drawn about the values of energy deposited in different material zones having various dimensions. The difference between the two codes used for calculations in materials physics and semiconductor technics, basically originates from the different physical models for numerical simulation of photon, positron, and electron transport through various materials.

The use of semiconductor materials in radiation processing, radiation therapy and diagnostics, and detection of cosmic radiation motivated development of numerical methods for its radiological characterization. This paper presents the application of the Monte Carlo method using the FOTELP-2K4 code for radiological characterization of Metal Oxide Semiconductor Field Effect Transistor (MOSFET) dosimeter. The advantages of MOSFET dosimeters include small size, immediate readout, and ease of use for a wide photon energy range. In order to determine the dosimeter response accurately, distribution of the absorbed dose in the MOSFET structure has been investigated. Our results show that the absorbed dose distribution calculated by the presented simulation model compares well with the published data.

This paper describes the application of the SRNA Monte Carlo package for proton transport simulations in complex geometry and different material compositions. The SRNA package was developed for 3D dose distribution calculation in proton therapy and dosimetry and it was based on the theory of multiple scattering. The decay of proton induced compound nuclei was simulated by the Russian MSDM model and our own using ICRU 63 data. The developed package consists of two codes: the SRNA-2KG, which simulates proton transport in combinatorial geometry and the SRNA-VOX, which uses the voxelized geometry using the CT data and conversion of the Hounsfields data to tissue elemental composition. Transition probabilities for both codes are prepared by the SRNADAT code. The simulation of the proton beam characterization by multi-layer Faraday cup, spatial distribution of positron emitters obtained by the SRNA-2KG code and intercomparison of computational codes in radiation dosimetry, indicate immediate application of the Monte Carlo techniques in clinical practice. In this paper, we briefly present the physical model implemented in the SRNA package, the ISTAR proton dose planning software, as well as the results of the numerical experiments with proton beams to obtain 3D dose distribution in the eye and breast tumour.

In this paper some of numerous applications of Monte Carlo software FOTELP package, in dosimetry and radiation. protection, as special domains of applied physic, are presented. It carried out conclusions suggesting whats it like the prospect of Monte Carlo technique regarding numerical experiments in medical physics and applied nuclear physics.