National primary standard for the unit of air kerma, air kerma rate, exposure, exposure rate, and x- and gamma-ray energy flux

2012 ◽  
Vol 55 (8) ◽  
pp. 849-857 ◽  
Author(s):  
A. V. Oborin ◽  
A. Yu. Villevalde ◽  
S. G. Trofimchuk
Keyword(s):  
Energy Flux ◽  
Gamma Ray ◽  
Primary Standard ◽  
Exposure Rate ◽  
National Primary Standard ◽  
Air Kerma ◽  
Air Kerma Rate

National primary standard of air kerma, air kerma rate, exposure, exposure rate and energy flux for X-rays and gamma radiation GET 8-2019

2020 ◽  
pp. 8-12
Author(s):  
Alexandr V. Oborin ◽  
Anna Y. Villevalde ◽  
Sergey G. Trofimchuk
Keyword(s):  
Gamma Radiation ◽  
Energy Flux ◽  
Primary Standard ◽  
Average Energy ◽  
Ion Pair ◽  
X Rays ◽  
Exposure Rate ◽  
Ionization Chambers ◽  
Air Kerma ◽  
Air Kerma Rate

The results of development of the national primary standard of air kerma, air kerma rate, exposure, exposure rate and energy flux for X-rays and gamma radiation GET 8-2011 in 2019 are presented according to the recommendations of the ICRU Report No. 90 “Key Data for Ionizing-Radiation Dosimetry: Measurement Standards and Applications”. The following changes are made to the equations for the units determination with the standard: in the field of X-rays, new correction coefficients of the free-air ionization chambers are introduced and the relative standard uncertainty of the average energy to create an ion pair in air is changed; in the field of gamma radiation, the product of the average energy to create an ion pair in air and the electron stopping-power graphite to air ratio for the cavity ionization chambers is changed. More accurate values of the units reproduced by GET 8-2019 are obtained and new metrological characteristics of the standard are stated.

RE-EVALUATION OF THE AIR KERMA PRIMARY STANDARD OF THE SMU IN 60Co AND 137Cs GAMMA RAY BEAMS

2019 ◽  
Vol 186 (2-3) ◽  
pp. 235-238
Author(s):  
Norman Durný
Keyword(s):  
Gamma Ray ◽  
Primary Standard ◽  
National Standard ◽  
Key Comparisons ◽  
Main Role ◽  
Correction Factors ◽  
Active Volume ◽  
Air Kerma ◽  
60Co Gamma

Abstract The primary standard for air kerma of the Slovak Institute of Metrology (SMU) as a part of national standard of dosimetric quantities of gamma radiation NE028/02, based on cylindrical graphite walled cavity ionization chamber was established in 2002 for the 60Co gamma ray beams. Since then the main role of SMU was to continuously maintain, develop and refurbish the standard with related accessory to ensure international equivalence. Since 2002, a re-evaluation of the active volume of the ionizing chamber, correction factors, the key data, due to adoption of ICRU Report 90(1), and changes of the calibrations methods and corrections of the equipment were made to obtain improved parameters. The range was extended for 137Cs gamma ray beams and key comparisons with the Bureau International des Poids et Mesures (BIPM) were performed. ICRU Report 90(1) implementation led to a decrease of the Gray of −0.84% for 60Co and −0.80% for 137Cs.

Revised correction factor for the UK national primary standard for air kerma for137Cs and60Co gamma-rays

Metrologia ◽  
2009 ◽  
Vol 46 (5) ◽  
pp. L26-L26 ◽  
Author(s):  
Julia Pearce ◽  
Graham Bass ◽  
Simon Duane ◽  
Rebecca Nutbrown ◽  
David Shipley
Keyword(s):  
Correction Factor ◽  
Gamma Rays ◽  
Primary Standard ◽  
National Primary Standard ◽  
Air Kerma ◽  
The Uk

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.

INVESTIGATION OF XENON-FILLED TUBE BREAKDOWN VOLTAGE AND DELAY RESPONSE AS POSSIBLE DOSIMETRIC PARAMETERS FOR SMALL GAMMA RAY AIR KERMA RATES

2020 ◽  
Vol 190 (1) ◽  
pp. 84-89
Author(s):  
Milić Pejović ◽  
Emilija Živanović ◽  
Miloš Živanović
Keyword(s):  
Gamma Radiation ◽  
Dose Rate ◽  
Breakdown Voltage ◽  
Radiation Dosimetry ◽  
Gamma Ray ◽  
Physical Processes ◽  
Rate Range ◽  
Air Kerma ◽  
Delay Response ◽  
Air Kerma Rate

Abstract This paper presents experimental results of dynamic breakdown voltage and delay response as functions of gamma ray air kerma rate for xenon-filled tube at 2.7 mbar pressure. Gamma ray air kerma rate range was considered from 123 nGy h–1 up to 12.3 mGy h–1 in order to investigate the possibility of the application of this tube in gamma radiation dosimetry. It was shown that the variations of the above-mentioned parameters are considerable up to the dose rate of 1.23 μGy h–1, which points to the possibility for application in small dose rate gamma ray dosimetry. Physical processes that make dominant impact to dynamic breakdown voltage and delay response during xenon-filled tube irradiation are also discussed in the paper.

scholarly journals METROLOGICAL SUPPORT OF DOSIMETRY GAMMA-RAY WITH ENERGY TO 10 MEV FOR RADIATION PROTECTION DEVICES

2017 ◽  
Vol 8 (3) ◽  
pp. 279-285
Author(s):  
D. I. Komar ◽  
R. V. Lukashevich ◽  
V. D. Guzov ◽  
S. A. Kutsen
Keyword(s):  
Radiation Protection ◽  
Gamma Ray ◽  
High Energy ◽  
Metrological Characteristics ◽  
Uniform Field ◽  
Air Kerma ◽  
Titanium Target ◽  
Protection Devices ◽  
Calibration Facility ◽  
Air Kerma Rate

The field of high-energy gamma-ray for the calibration of radiation protection devices can be obtained by capturing thermal neutrons from titanium target (to 7 MeV) and nickel target (to 10 MeV). The aim of this work was to determine the metrological characteristics of capture gamma-ray fields from titanium target and nickel target obtained at the AT140 Neutron Calibration Facility to provide dosimetry up to 10 MeV.We have chosen energy intervals in which we can calibrate dosimetry devices taking into account the accompanying generation of gamma-ray neutrons by the fast neutron source 238PuBe, the capture radiation of collimator materials and capture radiation from targets.We measured air kerma rate with the aid of the reference AT5350 dosimeter with the ionization chamber TM32002. Using the Monte-Carlo simulation, we obtained the energy distribution of the air kerma rate for targets. We determined the geometric dimensions of the uniform field and the interval of operating distances of the facility.We investigated the metrological characteristics of capture gamma-ray fields from titanium target and nickel target obtained at the AT140 Neutron Calibration Facility for dosimetric radiation protection devices. We showed that in such fields it is possible to calibrate dosimetry devices in the extended energy range up to 10 MeV. 

Calibration of a 7.6 cm x 7.6 cm (3 inch x 3 inch) Sodium Iodide Gamma Ray Spectrometer for Air Kerma Rate

2001 ◽  
Vol 94 (4) ◽  
pp. 309-316 ◽  
Author(s):  
R.L. Grasty ◽  
B.R.B. Walters ◽  
J. Hovgaard ◽  
J.R. LaMarre
Keyword(s):  
Sodium Iodide ◽  
Gamma Ray ◽  
Air Kerma ◽  
Gamma Ray Spectrometer ◽  
Air Kerma Rate
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