A Secondary Standard Ionisation Chamber for the Direct Measurement of Ambient Dose Equivalent H*(10)

1992 ◽  
Vol 40 (1) ◽  
pp. 35-38
Author(s):  
K.E. Duftschmid ◽  
J. Hizo ◽  
C. Strachotinsky
Keyword(s):  
Direct Measurement ◽  
Secondary Standard ◽  
Dose Equivalent ◽  
Ambient Dose Equivalent ◽  
Ionisation Chamber ◽  
Ambient Dose

EVALUATION OF AMBIENT DOSE EQUIVALENT SURROUNDING TRANSMISSION FULL-BODY SCANNERS

2020 ◽  
Vol 189 (4) ◽  
pp. 444-451
Author(s):  
Caio Caraciolo Rodrigues Elias ◽  
Domingos D’Oliveira Cardoso ◽  
Marcos Paulo Cavaliere de Medeiros ◽  
Cláudio Luiz de Oliveira ◽  
Sérgio Gavazza ◽  
...  
Keyword(s):  
Human Body ◽  
Maximum Energy ◽  
Dose Equivalent ◽  
Modes Of Operation ◽  
X Ray ◽  
Ambient Dose Equivalent ◽  
Ionisation Chamber ◽  
Ambient Dose ◽  
Full Body

Abstract This study analyses the ambient dose equivalent around transmission full-body scanners used in Brazilian prisons and airports. In order to achieve this goal, three transmission full-body scanners of the same model assembled by a Brazilian manufacturer were evaluated. Ambient dose equivalent rates were measured at several positions around these screening devices with the help of an ionisation chamber made by Ludlum, model 9DP. These systems consist of an X-ray generator with three distinct modes of operation, each with a unique value for maximum energy (100, 150 and 160 keV) and current (0.4, 0.5 and 0.9 mA). Results show the integrated dose per scan at each of the measurement positions considered, presenting values for ambient dose equivalent with and without an individual being scanned, in order to take into account the scattering due to the presence of a human body.

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.

ASSESSMENT OF TERRESTRIAL RADIATION BY DIRECT MEASUREMENT OF AMBIENT DOSE EQUIVALENT RATE OF BACKGROUND RADIATION

2018 ◽  
Vol 184 (2) ◽  
pp. 189-197 ◽  
Author(s):  
Mohammad Reza Kardan ◽  
Nahid Sadeghi ◽  
Nasrin Fathabadi ◽  
Ali Attarilar
Keyword(s):  
Direct Measurement ◽  
Activity Concentration ◽  
Background Radiation ◽  
Natural Radionuclides ◽  
Natural Radionuclide ◽  
Ground Level ◽  
Dose Equivalent ◽  
Equivalent Rate ◽  
Ambient Dose Equivalent ◽  
Ambient Dose

Abstract Estimation of terrestrial external radiation is essential for assessment of public exposure to natural radiation. During national survey of natural radionuclide in soil in Iran, 979 soil samples were collected from different locations, in the same time ambient dose equivalent rate was measured by a scintillator detector. In this work, terrestrial radiation was estimated by direct measurement of ambient dose equivalent rate of background radiation. The response of dose measuring instrument to cosmic radiation at ground level was measured and other components were discussed and estimated. For verification, terrestrial radiation derived from this method was compared with those calculated from activity concentration of natural radionuclides in soil. The averages of ambient dose equivalent rate derived from activity concentration of by natural radionuclide in soil and from direct measurement are 55.07 and 62.57 nSv/h, respectively. The source of statistical and systematic uncertainties are introduced and discussed.

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