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Title: Initial Experimental Verification of the Neutron Beam Modeling for the LBNL BNCT Facility

Abstract

In preparation for future clinical BNCT trials, neutron production via the 7Li(p,n) reaction as well as subsequent moderation to produce epithermal neutrons have been studied. Proper design of a moderator and filter assembly is crucial in producing an optimal epithermal neutron spectrum for brain tumor treatments. Based on in-phantom figures-of-merit,desirable assemblies have been identified. Experiments were performed at the Lawrence Berkeley National Laboratory's 88-inch cyclotron to characterize epithermal neutron beams created using several microampere of 2.5 MeV protons on a lithium target. The neutron moderating assembly consisted of Al/AlF3 and Teflon, with a lead reflector to produce an epithermal spectrum strongly peaked at 10-20 keV. The thermal neutron fluence was measured as a function of depth in a cubic lucite head phantom by neutron activation in gold foils. Portions of the neutron spectrum were measured by in-air activation of six cadmium-covered materials (Au, Mn, In, Cu, Co, W) with high epithermal neutron absorption resonances. The results are reasonably reproduced in Monte Carlo computational models, confirming their validity.

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Office of Science (US)
OSTI Identifier:
6540
Report Number(s):
LBNL-42956
TRN: US0406705
DOE Contract Number:
AC03-76SF00098
Resource Type:
Conference
Resource Relation:
Conference: The 15th International Conference on the Application of Accelerators in Research and Industry (CAARI), Conference location not supplied, Conference dates not supplied; Other Information: PBD: 19 Jan 1999
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ABSORPTION; ACCELERATORS; BRAIN; CYCLOTRONS; EPITHERMAL NEUTRONS; GOLD; LITHIUM; LUCITE; MODERATORS; NEOPLASMS; NEUTRON BEAMS; NEUTRONS; PHANTOMS; PROTONS; SIMULATION; TEFLON; THERMAL NEUTRONS; VERIFICATION

Citation Formats

Bleuel, D.L., Chu, W.T., Donahue, R.J., Ludewigt, B.A., McDonald, R.J., Smith, A.R., Stone, N.A., and Vuji, J. Initial Experimental Verification of the Neutron Beam Modeling for the LBNL BNCT Facility. United States: N. p., 1999. Web.
Bleuel, D.L., Chu, W.T., Donahue, R.J., Ludewigt, B.A., McDonald, R.J., Smith, A.R., Stone, N.A., & Vuji, J. Initial Experimental Verification of the Neutron Beam Modeling for the LBNL BNCT Facility. United States.
Bleuel, D.L., Chu, W.T., Donahue, R.J., Ludewigt, B.A., McDonald, R.J., Smith, A.R., Stone, N.A., and Vuji, J. Tue . "Initial Experimental Verification of the Neutron Beam Modeling for the LBNL BNCT Facility". United States. doi:. https://www.osti.gov/servlets/purl/6540.
@article{osti_6540,
title = {Initial Experimental Verification of the Neutron Beam Modeling for the LBNL BNCT Facility},
author = {Bleuel, D.L. and Chu, W.T. and Donahue, R.J. and Ludewigt, B.A. and McDonald, R.J. and Smith, A.R. and Stone, N.A. and Vuji, J.},
abstractNote = {In preparation for future clinical BNCT trials, neutron production via the 7Li(p,n) reaction as well as subsequent moderation to produce epithermal neutrons have been studied. Proper design of a moderator and filter assembly is crucial in producing an optimal epithermal neutron spectrum for brain tumor treatments. Based on in-phantom figures-of-merit,desirable assemblies have been identified. Experiments were performed at the Lawrence Berkeley National Laboratory's 88-inch cyclotron to characterize epithermal neutron beams created using several microampere of 2.5 MeV protons on a lithium target. The neutron moderating assembly consisted of Al/AlF3 and Teflon, with a lead reflector to produce an epithermal spectrum strongly peaked at 10-20 keV. The thermal neutron fluence was measured as a function of depth in a cubic lucite head phantom by neutron activation in gold foils. Portions of the neutron spectrum were measured by in-air activation of six cadmium-covered materials (Au, Mn, In, Cu, Co, W) with high epithermal neutron absorption resonances. The results are reasonably reproduced in Monte Carlo computational models, confirming their validity.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 19 00:00:00 EST 1999},
month = {Tue Jan 19 00:00:00 EST 1999}
}

Conference:
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  • In preparation for future clinical BNCT trials, neutron production via the {sup 7}Li(p,n) reaction as well as subsequent moderation to produce epithermal neutrons have been studied. Proper design of a moderator and filter assembly is crucial in producing an optimal epithermal neutron spectrum for brain tumor treatments. Based on in-phantom figures-of-merit, desirable assemblies have been identified. Experiments were performed at the Lawrence Berkeley National Laboratory{close_quote}s 88-inch cyclotron to characterize epithermal neutron beams created using several microamperes of 2.5 MeV protons on a lithium target. The neutron moderating assembly consisted of Al/AlF{sub 3} and Teflon, with a lead reflector to producemore » an epithermal spectrum strongly peaked at 10{endash}20 keV. The thermal neutron fluence was measured as a function of depth in a cubic lucite head phantom by neutron activation in gold foils. Portions of the neutron spectrum were measured by in-air activation of six cadmium-covered materials (Au, Mn, In, Cu, Co, W) with high epithermal neutron absorbtion resonances. The results are reasonably reproduced in Monte Carlo computational models, confirming their validity. {copyright} {ital 1999 American Institute of Physics.}« less
  • In preparation for future clinical BNCT trials, neutron production via the {sup 7}Li(p,n) reaction as well as subsequent moderation to produce epithermal neutrons have been studied. Proper design of a moderator and filter assembly is crucial in producing an optimal epithermal neutron spectrum for brain tumor treatments. Based on in-phantom figures-of-merit, desirable assemblies have been identified. Experiments were performed at the Lawrence Berkeley National Laboratory's 88-inch cyclotron to characterize epithermal neutron beams created using several microamperes of 2.5 MeV protons on a lithium target. The neutron moderating assembly consisted of Al/AlF{sub 3} and Teflon, with a lead reflector to producemore » an epithermal spectrum strongly peaked at 10-20 keV. The thermal neutron fluence was measured as a function of depth in a cubic lucite head phantom by neutron activation in gold foils. Portions of the neutron spectrum were measured by in-air activation of six cadmium-covered materials (Au, Mn, In, Cu, Co, W) with high epithermal neutron absorbtion resonances. The results are reasonably reproduced in Monte Carlo computational models, confirming their validity.« less
  • Three moderator materials, AlF{sub 3}/Al, D{sub 2}O and LiF, have been analyzed for clinical usefulness using the reaction {sup 7}Li(p,n) as an accelerator driven neutron source. Proton energies between 2.1 MeV and 2.6 MeV have been investigated. Radiation transport in the reflector/moderator assembly is simulated using the MCNP program. Depth-dose distributions in a head phanton are calculated with the BNCT-RTPE patient treatment planning program from INEEL using the MCNP generated neutron and photon spectra as the subsequent source. Clinical efficacy is compared using the current BMRR protocol for all designs. Depth-dose distributions are compared for a fixed normal tissue tolerancemore » dose of 12.5 Gy-Eq. Radiation analyses also include a complete anthropomorphic phantom. Results of organ and whole body dose components are presented for several designs. Results indicate that high quality accelerator beams may produce clinically favorable treatments to deep-seated tumors when compared to the BMRR beam. Also discussed are problems identified in comparing accelerator and reactor based designs using in-air figures of merit as well as some results of spectrum-averaged RBE`s.« less
  • In order to gain the neutron spectrum with proper components specification for BNCT, it is necessary to design a Beam Shape Assembling (BSA), include of moderator, collimator, reflector, gamma filter and thermal neutrons filter, in front of the initial radiation beam from the source. According to the result of MCNP4C simulation, the Northwest beam tube has the most optimized neuron flux between three north beam tubes of Tehran Research Reactor (TRR). So, it has been chosen for this purpose. Simulation of the BSA has been done in four above mentioned phases. In each stage, ten best configurations of materials withmore » different length and width were selected as the candidates for the next stage. The last BSA configuration includes of: 78 centimeters of air as an empty space, 40 centimeters of Iron plus 52 centimeters of heavy-water as moderator, 30 centimeters of water or 90 centimeters of Aluminum-Oxide as a reflector, 1 millimeters of lithium (Li) as thermal neutrons filter and finally 3 millimeters of Bismuth (Bi) as a filter of gamma radiation. The result of Calculations shows that if we use this BSA configuration for TRR Northwest beam tube, then the best neutron flux and spectrum will be achieved for BNCT. (authors)« less