Stem corrections for ionization chambers

Journal Article · Sat Nov 01 04:00:00 EST 1975 · Med. Phys., v. 2, no. 6, pp. 328-330

DOI:https://doi.org/10.1118/1.594202· OSTI ID:4128554

Ibbott, G S; Barnes, J E; Hall, G R; Hendee, W R

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 $sup 60$Co 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-cm$sup 3$ probe, a PTW transit dose probe, and an EGandG 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%. (AIP)

• Research Organization: University of Colorado Medical Center, Denver, Colorado 80220 and University of New Mexico School of Medicine, Albuquerque, New Mexico 87131
• Sponsoring Organization: USDOE
• NSA Number: NSA-33-009355
• OSTI ID: 4128554
• Journal Information: Med. Phys., v. 2, no. 6, pp. 328-330, Journal Name: Med. Phys., v. 2, no. 6, pp. 328-330; ISSN MPHYA
• Country of Publication: United States
• Language: English

Related Subjects

*IONIZATION CHAMBERS-- CORRECTIONS
440102* --Instrumentation--Radiation Instrumentation-- Radiation Dosemeters
COMPARATIVE EVALUATIONS
DOSEMETERS
DOSIMETRY
N46120* --Instrumentation--Radiation Detection Instruments-- Radiation Dosimeters
RADIATION DOSES
RADIATION MONITORS