2006
DOI: 10.1088/0031-9155/51/20/008
|View full text |Cite
|
Sign up to set email alerts
|

Ion recombination in parallel-plate free-air ionization chambers for synchrotron radiation

Abstract: The saturation characteristics of two sizes of parallel-plate free-air ionization chambers were investigated for synchrotron radiation at bending-magnet, wiggler and undulator beamlines of SPring-8. The gaps of the electrodes were 4.2 and 85 mm. The monoenergetic photon energies ranged from 10 to 115.56 keV and the air kerma rates from 0.2 mGy s-1 to 150 kGy s-1. Ion recombination at the high dose rate was found to be smaller than that predicted by Boag's expression, which was based on volume recombination, an… Show more

Help me understand this report

Search citation statements

Order By: Relevance

Paper Sections

Select...
1
1
1
1

Citation Types

1
16
0

Year Published

2009
2009
2021
2021

Publication Types

Select...
8

Relationship

2
6

Authors

Journals

citations
Cited by 14 publications
(18 citation statements)
references
References 18 publications
1
16
0
Order By: Relevance
“…A detailed description of the design and use of ion chambers is beyond the scope of this paper, but generally these devices consist of two metal plates on either side of a gas-filled box with a voltage applied across the plates. Voltages of order 100-2000 V cm À1 are required to avoid space charge saturation for highly brilliant X-ray beams (Wyckof, 1979;Nariyama, 2006). X-ray photons with the wavelengths used for MX interact with matter in one of three ways: photoelectric emission, elastic scattering or Compton scattering.…”
Section: Ionization Chambersmentioning
confidence: 99%
“…A detailed description of the design and use of ion chambers is beyond the scope of this paper, but generally these devices consist of two metal plates on either side of a gas-filled box with a voltage applied across the plates. Voltages of order 100-2000 V cm À1 are required to avoid space charge saturation for highly brilliant X-ray beams (Wyckof, 1979;Nariyama, 2006). X-ray photons with the wavelengths used for MX interact with matter in one of three ways: photoelectric emission, elastic scattering or Compton scattering.…”
Section: Ionization Chambersmentioning
confidence: 99%
“…at high electric field), free electrons that do not attach to oxygen molecules play an important role, as has been shown via the pulse shape (Nariyama, 2012). Owing to this effect, a lower electric field than expected has been observed at saturation with high-intensity X-rays (Nariyama, 2006).…”
Section: Effects Of Space Charge and Free Electronsmentioning
confidence: 86%
“…For 10 keV X-rays incident on an ionization chamber with a 4.2 mm gap, equation (10) reduces to the following simple relation, where 5 Â 10 13 V 2 A À1 m À1 has been substituted for (Niatel, 1967;Nariyama, 2006) and 3 Â 10 10 V m C À1 for (ICRU, 1982), Plots of K against E demonstrating that K is inversely proportional to E. The circles, squares and triangles denote IC1, IC2 and IC3, respectively. The open and closed marks are data for 10 and 15 keV X-rays, respectively.…”
Section: Comparison Of Saturation Curves For High-intensity X-rays Wimentioning
confidence: 99%
“…, averaged over their characteristic time response) during treatment can be up to tens of μA, two to three orders of magnitude larger than that with continuous beam accelerators. At the resulting high instantaneous dose delivery rates, the response of air ionization chambers conventionally used as treatment dosimeters becomes nonlinear, due to recombination of the produced ions (Almond 1984, Palmans et al 2006, Nariyama 2006). This effect makes it highly desirable to develop alternative real-time dosimeters that operate linearly up to much higher dose rates.…”
Section: Introductionmentioning
confidence: 99%