THE PERFORMANCE OF THE "NPL SECONDARY STANDARD, THERAPY LEVEL X-RAY EXPOSURE METER"

Abstract The individual monitoring service at the Helmholtz Zentrum München has extended the calibration facilities provided at the Munich IAEA/WHO secondary standard dosimetry laboratory with a new fully automated X-ray calibration facility for the calibration of personal dosemeters according to the ISO 4037 standard series. This work describes the X-ray irradiation system and the automated dosemeter transport system as well as the measurements performed to characterize the photon fields and to ascertain conformity to the ISO standard. Standard uncertainties of the radiation quantities provided by the system are given together with a discussion of some of the problems that are encountered in fulfilling the requirements of a matched field according to the latest drafts of the ISO 4037-1 standard.

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PENGARUH PENGGUNAAN FAKTOR KALIBRASI S-137Cs PADA PENGUKURAN DOSIS SINAR-X DENGAN DETEKTOR IONISASI HP(10) STANDAR SEKUNDER

Jurnal Standardisasi ◽

10.31153/js.v22i1.777 ◽

2020 ◽

Vol 22 (1) ◽

pp. 45

Author(s):

Assef Firnando Firmansyah ◽

Okky Agassy Firmansyah ◽

Sri Inang Sunaryati ◽

Nurman Rajagukguk

Keyword(s):

Radiation Dose ◽

Energy Range ◽

Radiation Energy ◽

Calibration Factor ◽

Secondary Standard ◽

Reference Source ◽

X Ray ◽

Dose Variation

The value of Hp(10) can be measured directly using Hp(10) secondary standard chamber that developed by Physikalisch Technische Bundensalt (PTB), Germany. Hp(10) secondary standard chamber type T 34035/0046 is connected with electrometer PTW Unidos T 10001 / Ns.11814. In this paper, the exposure was carried out by X-ray sources and 137Cs for dose and radiation energy variations.The variations energy of X-ray were carried out using ISO 4037-1 quality narrow (N) spectrum within N-40 to N-300, while the radiation dose variations were carried out in the dose within range 0.1 mSv to 20 mSv. The use of the S-137Cs calibration factor for the Hp(10) secondary standard chamber with an X-ray irradiation source were carried out and obtained a fairly good response result not in all energy ranges. The result obtained a relatively constant response to energy of 65 keV to 250 keV (energy quality N-80 to N-250), this corresponds to the deviation obtained i.e ≤ 7% from the normalization reference source of 137Cs at 662 keV energy. Whereas for deviations below 3%, a relatively constant response has founded in the energy range of 100 keV to 250 keV (energy quality N-120 to N-250). The result obtained linier measurement on variations in dose according to changes in dose variation. The Hp(10) secondary standard chamber is capable for measuring variations of radiation dose, i.e from variations of 0.1 mSv to 20 mSv.

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Space and Time Distribution of Hard X-Ray Emission in a Loop at the Beginning of a Flare

International Astronomical Union Colloquium ◽

10.1017/s0252921100025446 ◽

1994 ◽

Vol 144 ◽

pp. 275-277

Author(s):

M. Karlický ◽

J. C. Hénoux

Keyword(s):

Time Distribution ◽

Electron Bombardment ◽

Spatial Evolution ◽

Superthermal Electrons ◽

Flare Loop ◽

X Ray ◽

Superthermal Electron ◽

Flare Loops ◽

Chromospheric Evaporation ◽

Temporal And Spatial

AbstractUsing a new ID hybrid model of the electron bombardment in flare loops, we study not only the evolution of densities, plasma velocities and temperatures in the loop, but also the temporal and spatial evolution of hard X-ray emission. In the present paper a continuous bombardment by electrons isotropically accelerated at the top of flare loop with a power-law injection distribution function is considered. The computations include the effects of the return-current that reduces significantly the depth of the chromospheric layer which is evaporated. The present modelling is made with superthermal electron parameters corresponding to the classical resistivity regime for an input energy flux of superthermal electrons of 109erg cm−2s−1. It was found that due to the electron bombardment the two chromospheric evaporation waves are generated at both feet of the loop and they propagate up to the top, where they collide and cause temporary density and hard X-ray enhancements.

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Some Problems in Understanding the Solar Corona

International Astronomical Union Colloquium ◽

10.1017/s025292110002491x ◽

1994 ◽

Vol 144 ◽

pp. 1-9

Author(s):

A. H. Gabriel

Keyword(s):

Solar Corona ◽

Solar Atmosphere ◽

Theoretical Modelling ◽

Total System ◽

Major Advance ◽

X Ray ◽

Proper Perspective ◽

Space Observations

The development of the physics of the solar atmosphere during the last 50 years has been greatly influenced by the increasing capability of observations made from space. Access to images and spectra of the hotter plasma in the UV, XUV and X-ray regions provided a major advance over the few coronal forbidden lines seen in the visible and enabled the cooler chromospheric and photospheric plasma to be seen in its proper perspective, as part of a total system. In this way space observations have stimulated new and important advances, not only in space but also in ground-based observations and theoretical modelling, so that today we find a well-balanced harmony between the three techniques.

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