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Implementation of water calorimetry in a 180 MeV scanned pulsed proton beam including an experimental determination of k(Q) for a Farmer chamber

Medin, Joakim LU (2010) In Physics in Medicine and Biology 55(12). p.3287-3298
Abstract
Water calorimetric measurements have been performed in a 180 MeV scanned pulsed proton beam and the absorbed dose determined has been compared with the results obtained using two NE2571 Farmer chambers and the IAEA TRS-398 code of practice. The depth of measurement in water corresponded to a residual range of R-res = 16.5 cm, corresponding to a mean energy of about 150 MeV. Ionization chambers were calibrated in terms of the absorbed dose to water in Co-60 at the Swedish Secondary Standard Dosimetry Laboratory, directly traceable to Bureau International des Poids et Mesures. The present experimental investigation has shown that water calorimetry is feasible in a high-energy scanned pulsed proton beam. When comparing the results obtained... (More)
Water calorimetric measurements have been performed in a 180 MeV scanned pulsed proton beam and the absorbed dose determined has been compared with the results obtained using two NE2571 Farmer chambers and the IAEA TRS-398 code of practice. The depth of measurement in water corresponded to a residual range of R-res = 16.5 cm, corresponding to a mean energy of about 150 MeV. Ionization chambers were calibrated in terms of the absorbed dose to water in Co-60 at the Swedish Secondary Standard Dosimetry Laboratory, directly traceable to Bureau International des Poids et Mesures. The present experimental investigation has shown that water calorimetry is feasible in a high-energy scanned pulsed proton beam. When comparing the results obtained with water calorimetry and ionometry, the beam quality correction factor, k(Q), could be determined for the two NE2571 ionization chambers used. The k(Q)-factor was found to be 1.032 +/- 0.013, which is in good agreement with the factor tabulated in IAEA TRS-398 for this chamber type (1.039 +/- 0.018). The present result has also been compared with a previously obtained result in a passively scattered proton beam having similar energy. This comparison yielded a 1.1% deviation, which is not significant considering the combined uncertainties of the two experimental determinations of k(Q). The dominating contribution to the combined uncertainty stems from the correction factor for ion recombination in the scanned proton beam (1%), and further studies are required in order to reduce this uncertainty and reveal any possible differences in the k(Q)-factor between these two proton beam delivery techniques. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physics in Medicine and Biology
volume
55
issue
12
pages
3287 - 3298
publisher
IOP Publishing
external identifiers
  • wos:000278147800002
  • scopus:77952652661
ISSN
1361-6560
DOI
10.1088/0031-9155/55/12/002
language
English
LU publication?
yes
id
93bbd866-5c76-424c-9242-1b2c91a169d6 (old id 1616653)
date added to LUP
2010-06-22 14:51:13
date last changed
2018-05-29 09:25:29
@article{93bbd866-5c76-424c-9242-1b2c91a169d6,
  abstract     = {Water calorimetric measurements have been performed in a 180 MeV scanned pulsed proton beam and the absorbed dose determined has been compared with the results obtained using two NE2571 Farmer chambers and the IAEA TRS-398 code of practice. The depth of measurement in water corresponded to a residual range of R-res = 16.5 cm, corresponding to a mean energy of about 150 MeV. Ionization chambers were calibrated in terms of the absorbed dose to water in Co-60 at the Swedish Secondary Standard Dosimetry Laboratory, directly traceable to Bureau International des Poids et Mesures. The present experimental investigation has shown that water calorimetry is feasible in a high-energy scanned pulsed proton beam. When comparing the results obtained with water calorimetry and ionometry, the beam quality correction factor, k(Q), could be determined for the two NE2571 ionization chambers used. The k(Q)-factor was found to be 1.032 +/- 0.013, which is in good agreement with the factor tabulated in IAEA TRS-398 for this chamber type (1.039 +/- 0.018). The present result has also been compared with a previously obtained result in a passively scattered proton beam having similar energy. This comparison yielded a 1.1% deviation, which is not significant considering the combined uncertainties of the two experimental determinations of k(Q). The dominating contribution to the combined uncertainty stems from the correction factor for ion recombination in the scanned proton beam (1%), and further studies are required in order to reduce this uncertainty and reveal any possible differences in the k(Q)-factor between these two proton beam delivery techniques.},
  author       = {Medin, Joakim},
  issn         = {1361-6560},
  language     = {eng},
  number       = {12},
  pages        = {3287--3298},
  publisher    = {IOP Publishing},
  series       = {Physics in Medicine and Biology},
  title        = {Implementation of water calorimetry in a 180 MeV scanned pulsed proton beam including an experimental determination of k(Q) for a Farmer chamber},
  url          = {http://dx.doi.org/10.1088/0031-9155/55/12/002},
  volume       = {55},
  year         = {2010},
}