scholarly journals Primary reference in terms of air kerma for ionizing radiation fields produced by an electrostatic electron accelerator

2019 ◽  
Author(s):  
Jean-Marc Bordy ◽  
Valentin Blideanu ◽  
Arnaud Chapon ◽  
Gabriel Dupont ◽  
Dorin Dusciac ◽  
...  
Keyword(s):  
International System ◽  
X Rays ◽  
Dose Equivalent ◽  
Air Kerma ◽  
Radiation Fields ◽  
Tantalum Target ◽  
System Of Units ◽  
Ambient Dose Equivalent ◽  
Primary Reference ◽  
Ambient Dose

Based on a radiation field produced by an electrostatic accelerator, a radiation survey meter test and calibration facility has been designed and characterized in terms of air kerma and ambient dose equivalent. The electron beam impinges a tantalum target to produce X-rays. The spectrum has been measured and calculated. Traceability to the International System of units is achieved by means of a calibration with a primary dosimeter for air kerma.

DEVELOPMENT OF A NEW SECONDARY STANDARD FOR H*(10)

2020 ◽  
Vol 188 (3) ◽  
pp. 378-382
Author(s):  
K Bairlein ◽  
B Behnke ◽  
O Hupe
Keyword(s):  
Ionization Chamber ◽  
Secondary Standard ◽  
Dose Equivalent ◽  
Air Kerma ◽  
Radiation Fields ◽  
Ambient Dose Equivalent ◽  
Conversion Coefficients ◽  
Aluminium Coating ◽  
Pulsed Fields ◽  
Ambient Dose

Abstract A secondary standard for ambient dose equivalent, H*(10), is necessary for the dissemination of the unit Sievert (Sv), but there is no such standard commercially available currently. Furthermore, the measurement of H*(10) instead of calculating H*(10) from air kerma and conversion coefficients is needed for unknown radiation fields. We developed a prototype of a new secondary standard for H*(10) based on a spherical 1 l ionization chamber for air kerma. This chamber was modified with copper wires at the inner surface to adjust the response of the chamber according to H*(10). Additionally, a Makrolon shell and an aluminium coating were added to optimize the response at energies below 50 keV. The prototype fulfils the requirements given in ISO 4037-2 in the energy range from 12 keV to 7 MeV. In combination with an electrometer, it can be used as area dosemeter, suitable for pulsed fields and for low energy radiation.

ESTABLISHMENT OF A LOW DOSE RATE GAMMA RAY CALIBRATION FIELD FOR ENVIRONMENTAL RADIATION MONITORING DEVICES

2019 ◽  
Vol 187 (1) ◽  
pp. 61-68
Author(s):  
Munehiko Kowatari ◽  
Hiroshi Yoshitomi ◽  
Sho Nishino ◽  
Yoshihiko Tanimura ◽  
Tetsuya Ohishi ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Radiation Monitoring ◽  
Dose Equivalent ◽  
Environmental Radiation ◽  
Air Kerma ◽  
Ambient Dose Equivalent ◽  
Reference Air Kerma Rate ◽  
Monitoring Devices ◽  
Air Kerma Rate ◽  
Ambient Dose

Abstract For routine calibration of dosemeters used for environmental radiation monitoring, a low dose rate 137Cs gamma ray calibration field that fully satisfies the requirement of the ISO 4037 series was established in the Facility of Radiation Standards in Japan Atomic Energy Agency. Two different methods were employed to determine the reference air kerma rate, namely a conventional ionisation chamber and a G(E) function method used a newly developed scintillation spectrometer. To fulfil the requirement of the ISO 4037 and suppress scattering of Cs gamma ray within the room as far as possible, a suitable lead collimator was introduced to limit the irradiation area at test points and placed at the middle height in an irradiation room with a grating floor. From measured results of de-convoluted photon fluence spectrum and the variation of evaluated reference air kerma rates between 1.0 m and 3.0 m from the centre of the source, gamma ray scattering from the room structures was found to be negligible. The reference air kerma rate at distances between1.0 m and 3.0 m could be then interpolated by simply considering the inverse square law of the distance and air attenuation. The resulting Cs gamma ray calibration field could provide ambient dose equivalent rates of 0.7–7.2 μSv h−1 for use with environmental radiation monitoring devices. Finally, we attempted to calibrate a widely used NaI(Tl) scintillation survey metre, obtaining a quite satisfactory calibration factor. These results also imply that such survey metres can be employed to monitor affected areas and assess the progress of decontamination, as they can provide appropriate measurements of the ambient dose equivalent rate.

scholarly journals Dose Rate Measurements in Pulsed Radiation Fields by Means of an Organic Scintillator

2021 ◽  
Vol 253 ◽  
pp. 09002
Author(s):  
Theresa Werner ◽  
Roland Beyer ◽  
Richard Biedermann ◽  
Marko Gerber ◽  
Jürgen Götze ◽  
...  
Keyword(s):  
Digital Data ◽  
Laser Machining ◽  
Dose Equivalent ◽  
Organic Scintillator ◽  
Radiation Fields ◽  
Medical Diagnostic ◽  
Ambient Dose Equivalent ◽  
Short Time ◽  
Ambient Dose

A deficiency in the implementation of current radiation protection is the determination of the ambient dose equivalent H*(10) and the directional dose equivalent H´(0.07) in pulsed radiation fields. Conventional dosimeter systems are not suitable for measurements in photon fields comprising short radiation pulses, which consequently leads to high detector loads in short time periods. Nevertheless, due to the implementation of advanced medical accelerators for cancer therapy, new medical diagnostic devices as well as various laser machining systems, there is an urgent need for suitable dosimeter systems for real time dosimetry. In this paper, a detector concept based on an organic scintillator and a full digital data analysis with the aim of developing a portable, battery powered measurement system is presented.

scholarly journals Correlation between calculated and measured values of gamma dose rate in air in forests contaminated with 137Cs: the remote period after the Chernobyl accident

2020 ◽  
Vol 12 (4) ◽  
pp. 37-46 ◽  
Author(s):  
Valery P. Ramzaev ◽  
Anatoly N. Barkovsky
Keyword(s):  
Vertical Distribution ◽  
Dose Rate ◽  
Chernobyl Accident ◽  
Gamma Dose ◽  
Dose Equivalent ◽  
Air Kerma ◽  
Equivalent Rate ◽  
Ambient Dose Equivalent ◽  
Air Kerma Rate ◽  
Ambient Dose

In 2015–2016, 13 forest and 7 virgin grassland plots located in the south-western districts of the Bryansk region were surveyed. The aim of the work was to experimentally test the possibility of using a method for calculating the dose rate of gamma radiation in air in radioactively contaminated forests in a remote period after the Chernobyl accident. According to the results of gamma-spectrometric analysis of soil samples obtained at the sites in another study, the values of inventory and vertical distribution of 137Cs in the upper 20 cm layer were established. In this paper, these data were used to calculate the air kerma rate using a method taken from literature. In addition, at the sites of soil sampling, ambient dose equivalent rate in air was measured, and the contribution of 137Cs to the total gamma dose rate was determined with a field gamma spectrometer-dosemeter. The measured values of the ambient dose equivalent rate from 137Cs correlated positively and statistically significantly with the calculated values of the air kerma rate. The Spearman correlation coefficient was 0.989 (P < 0.01) for the location “forest” and 0.893 (P < 0.05) for the location “grassland”. There was no statistically significant difference between the “forest” and “grassland” locations when analyzing the ratio of the measured dose rate values to the calculated dose rate values (the Mann-Whitney U test, P > 0.05). Results of this work show that, when calculating gamma radiation dose rate in air in forests at a remote stage after the Chernobyl accident, it is enough to know the 137Cs inventory in the upper 20 cm soil layer and a detailed picture of vertical distribution of the radionuclide in this layer. The presence of woody biomass can be neglected. This dose rate estimate is conservative. However, a degree of overestimation of the dose rate in air is small, within +10%, which is quite acceptable for determining the external effective dose rate for an individual in the radioactively contaminated forest.

scholarly journals Ambient dose equivalent measurements in secondary radiation fields at proton therapy facility CCB IFJ PAN in Krakow using recombination chambers

Nukleonika ◽  
2016 ◽  
Vol 61 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Edyta A. Jakubowska ◽  
Michał A. Gryziński ◽  
Natalia Golnik ◽  
Piotr Tulik ◽  
Liliana Stolarczyk ◽  
...  
Keyword(s):  
Nuclear Physics ◽  
Gamma Probe ◽  
Secondary Radiation ◽  
Dose Equivalent ◽  
Radiation Fields ◽  
Tissue Equivalent ◽  
Ambient Dose Equivalent ◽  
Dosimetric System ◽  
Ambient Dose

AbstractThis work presents recombination methods used for secondary radiation measurements at the Facility for Proton Radiotherapy of Eye Cancer at the Institute for Nuclear Physics, IFJ, in Krakow (Poland). The measurements ofH*(10) were performed, with REM-2 tissue equivalent chamber in two halls of cyclotrons AIC-144 and Proteus C-235 and in the corridors close to treatment rooms. The measurements were completed by determination of gamma radiation component, using a hydrogen-free recombination chamber. The results were compared with the measurements using rem meter types FHT 762 (WENDI-II) and NM2 FHT 192 gamma probe and with stationary dosimetric system.

The Design of an Ambient Neutron Dose-Equivalent Meter

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Xia Wenming ◽  
Jia Mingchun ◽  
Guo Zhirong
Keyword(s):  
Neutron Radiation ◽  
Monte Carlo Code ◽  
Energy Response ◽  
Dose Equivalent ◽  
Neutron Dosimeter ◽  
Radiation Fields ◽  
Ambient Dose Equivalent ◽  
Ambient Dose ◽  
Detector Design ◽  
Single Counter

At present, most of the developed neutron dosimeters used to measure the neutron ambient dose-equivalent that has a moderator with a single counter, applied in neutron radiation fields within large range energies from thermal to MeV neutrons, are not a satisfaction to energy response. The purpose of this article is to design a suitable neutron dosimeter for radiation protection purpose. In order to overcome the disadvantage of the energy response of the neutron dosimeters combining a single sphere with a single counter, three spheres and three H3e counters were combined for the detector design. The response function of moderators with different thicknesses combined with SP9 H3e counters were calculated with Monte Carlo code MCNP 4C. The selection of three different thicknesses of the moderating polyethylene sphere was done with a MATLAB program. A suitable combination of three different thicknesses was confirmed for the detector design. The electronic system of the neutron dosimeter was introduced. The results of ambient dose-equivalent per unit fluence in different radiation areas were calculated, analyzed, and compared with the values recommended in the ISO standard. The calculated result explains that it is very significant to this design of neutron dosimeter; it may be applied to the monitor of the ambient dose in the neutron radiation fields, improving at present the status of the energy response of neutron dosimeters.

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