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Record Details

Record 11 of 21070
Wall effects observed in tissue-equivalent proportional counters from 1.05 GeV/nucleon iron-56 particles
Author and Affiliation:
Rademacher, S. E.(Colorado State University, Department of Radiological Health Sciences, Fort Collins 80523, United States)
Borak, T. B.
Zeitlin, C.
Heilbronn, L.
Miller, J.
Chatterjee, A. [Principal Investigator]
Abstract: Tissue-equivalent proportional counters (TEPCs) have been used to measure energy deposition in simulated volumes of tissue ranging in diameter from 0.1 to 10 microm. There has been some concern that the wall used to define the volume of interest could influence energy deposition within the sensitive volume because it has a density significantly greater than that of the cavity gas. These effects become important for high-velocity heavy ions. Measurements of energy deposition were made for 1 GeV/nucleon iron particles in a TEPC simulating a 1-microm-diameter sphere of tissue. The TEPC was nested within a particle spectrometer that provided identification and flight path of individual particles. Energy deposition was studied as a function of pathlength through the TEPC. Approximately 30% of the energy transfer along trajectories through the center of the detector escapes the sensitive volume. The response of the TEPC, for trajectories through the detector, is always larger than calculations for energy loss in a homogeneous medium. This enhancement is greatest for trajectories near the cavity/wall interface. An integration of the response indicates that charged-particle equilibrium is essentially achieved for a wall thickness of 2.54 mm. However, estimates of the linear energy transfer for the incident particles are influenced by these wall effects.
Publication Date: Apr 01, 1998
Document ID:
20040172740
(Acquired Dec 09, 2004)
Subject Category: LIFE SCIENCES (GENERAL)
Document Type: Journal Article
Publication Information: Radiation research; p. 387-95; (ISSN 0033-7587); Volume 149; 4
Publisher Information: United States
Description: In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: IRON ISOTOPES; NUCLEONS; PROPORTIONAL COUNTERS; RADIATION MEASUREMENT; WALLS; GASES; LINEAR ENERGY TRANSFER (LET); RADIATION EFFECTS; RADIOACTIVE ISOTOPES; RADIOCHEMISTRY; SILICON; SYNCHROTRONS
Other Descriptors: RADIOMETRY/INSTRUMENTATION; GASES; IRON RADIOISOTOPES; LINEAR ENERGY TRANSFER; RADIOCHEMISTRY; SILICON; SUPPORT, U.S. GOV'T, NON-P.H.S; SYNCHROTRONS; NASA DISCIPLINE RADIATION HEALTH; NON-NASA CENTER
Availability Source: Other Sources
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