Stem corrections for ionization chambers

Geoffrey S. Ibbott; J. Edward Barnes; G. Richard Hall; William R. Hendee

doi:10.1118/1.594202

Stem corrections for ionization chambers

Geoffrey S. Ibbott, J. Edward Barnes, G. Richard Hall, William R. Hendee

Research output: Contribution to journal › Comment/debate › peer-review

10 Scopus citations

Abstract

Ionization chambers often exhibit a stem effect, caused by interactions of radiation with air near the chamber end, or with dielectric in the chamber stem or cable. These interactions contribute to the apparent measured exposure. To determine the stem effect for several common ionization chamber systems, exposures were measured with TLD capsules placed at the center of 60Co fields of various sizes. These exposure measurements then were repeated with various ionization chamber systems, including two Victoreen R meters (25- and 100-R chambers), a Capintec 192 dosimeter with a Farmer 0.6-cm3 probe, a PTW transit dose probe, and an EG&G IC-18 probe with a Keithley 610-B electrometer. From a comparison of TLD and ionization chamber measurements of the variation in exposure rate with field size, stem corrections for the different systems were determined within 1%.

Original language	English (US)
Pages (from-to)	328-330
Number of pages	3
Journal	Medical physics
Volume	2
Issue number	6
DOIs	https://doi.org/10.1118/1.594202
State	Published - Nov 1975
Externally published	Yes

Keywords

COMPARATIVE EVALUATIONS
DOSEMETERS
IONIZATION CHAMBERS
RADIATION DOSES
RADIATION MONITORS

ASJC Scopus subject areas

Biophysics
Radiology Nuclear Medicine and imaging

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10.1118/1.594202

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title = "Stem corrections for ionization chambers",

abstract = "Ionization chambers often exhibit a stem effect, caused by interactions of radiation with air near the chamber end, or with dielectric in the chamber stem or cable. These interactions contribute to the apparent measured exposure. To determine the stem effect for several common ionization chamber systems, exposures were measured with TLD capsules placed at the center of 60Co fields of various sizes. These exposure measurements then were repeated with various ionization chamber systems, including two Victoreen R meters (25- and 100-R chambers), a Capintec 192 dosimeter with a Farmer 0.6-cm3 probe, a PTW transit dose probe, and an EG&G IC-18 probe with a Keithley 610-B electrometer. From a comparison of TLD and ionization chamber measurements of the variation in exposure rate with field size, stem corrections for the different systems were determined within 1%.",

keywords = "COMPARATIVE EVALUATIONS, DOSEMETERS, IONIZATION CHAMBERS, RADIATION DOSES, RADIATION MONITORS",

author = "Ibbott, {Geoffrey S.} and Barnes, {J. Edward} and Hall, {G. Richard} and Hendee, {William R.}",

year = "1975",

month = nov,

doi = "10.1118/1.594202",

language = "English (US)",

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pages = "328--330",

journal = "Medical physics",

issn = "0094-2405",

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}

TY - JOUR

T1 - Stem corrections for ionization chambers

AU - Ibbott, Geoffrey S.

AU - Barnes, J. Edward

AU - Hall, G. Richard

AU - Hendee, William R.

PY - 1975/11

Y1 - 1975/11

N2 - Ionization chambers often exhibit a stem effect, caused by interactions of radiation with air near the chamber end, or with dielectric in the chamber stem or cable. These interactions contribute to the apparent measured exposure. To determine the stem effect for several common ionization chamber systems, exposures were measured with TLD capsules placed at the center of 60Co fields of various sizes. These exposure measurements then were repeated with various ionization chamber systems, including two Victoreen R meters (25- and 100-R chambers), a Capintec 192 dosimeter with a Farmer 0.6-cm3 probe, a PTW transit dose probe, and an EG&G IC-18 probe with a Keithley 610-B electrometer. From a comparison of TLD and ionization chamber measurements of the variation in exposure rate with field size, stem corrections for the different systems were determined within 1%.

AB - Ionization chambers often exhibit a stem effect, caused by interactions of radiation with air near the chamber end, or with dielectric in the chamber stem or cable. These interactions contribute to the apparent measured exposure. To determine the stem effect for several common ionization chamber systems, exposures were measured with TLD capsules placed at the center of 60Co fields of various sizes. These exposure measurements then were repeated with various ionization chamber systems, including two Victoreen R meters (25- and 100-R chambers), a Capintec 192 dosimeter with a Farmer 0.6-cm3 probe, a PTW transit dose probe, and an EG&G IC-18 probe with a Keithley 610-B electrometer. From a comparison of TLD and ionization chamber measurements of the variation in exposure rate with field size, stem corrections for the different systems were determined within 1%.

KW - COMPARATIVE EVALUATIONS

KW - DOSEMETERS

KW - IONIZATION CHAMBERS

KW - RADIATION DOSES

KW - RADIATION MONITORS

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JO - Medical physics

JF - Medical physics

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ER -

Stem corrections for ionization chambers

Abstract

Keywords

ASJC Scopus subject areas

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