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Title: LET spectrum measurements in Cr-39 PNTD with AFM

Abstract

Energetic protons, neutrons, and heavy ions undergoing collisions with target nuclei of varying Z can produce residual heavy recoil fragments via intra-nuclear cascade/evaporation reactions. The particles produced in these non-elastic collisions generally have such extremely short range ({approx}< 10 {mu}m) that they cannot be directly observed by conventional detection methods including CR-39 plastic nuclear track detector (PNTD) that has been chemically etched for analysis by standard visible light microscopy. However, high-LET recoil fragments having range on the order of several cell diameters can be produced in tissue during radiotherapy using proton and carbon beams. We have developed a method to analyze short-range, high-LET tracks in CR-39 plastic nuclear track detector (PNTD) using short duration chemical etching ({approx}< 1 {mu}m) followed by automated atomic force microscope (AFM) scanning. The post-scan data processing used in this work was based on semi-automated matrix analysis opposed to traditional grey-scale image analysis. This method takes advantage of the 3-D data obtained via AFM to achieve robust discrimination of nuclear tracks from other features. Through automation of AFM scanning, sufficient AFM scan frames were obtained to attain an LET spectrum spanning the LET range from 200-1500 keV/{mu}m. In addition to our experiments, simulations were carried outmore » with the Monte Carlo transport code, FLUKA. To demonstrate this method, CR-39 PNTD was exposed to the proton therapy beam at Loma Linda University Medical Center (LLUMC) at 60 and 230 MeV. Additionally, detectors were exposed to I GeV protons at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL). For these exposures CR-39 PNTD, Al and Cu target foils were used between detector layers.« less

Authors:
 [1];  [2];  [2];  [3];  [4]
  1. Los Alamos National Laboratory
  2. OSU, PHYSICS
  3. NIRS, HIMAC
  4. UNIV OF SAN FRANCISCO
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1026830
Report Number(s):
LA-UR-10-05385; LA-UR-10-5385
TRN: US1105142
DOE Contract Number:  
AC52-06NA25396
Resource Type:
Conference
Resource Relation:
Conference: CAARI 2010 ; August 8, 2010 ; Fort Worth Tx
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ATOMIC FORCE MICROSCOPY; AUTOMATION; CARBON IONS; DATA PROCESSING; DETECTION; DIELECTRIC TRACK DETECTORS; ETCHING; F CODES; HEAVY IONS; ION BEAMS; KEV RANGE; LET; MONTE CARLO METHOD; NEUTRONS; NUCLEI; PARTICLES; PARTICLE TRACKS; PROTONS; PROTON BEAMS; RADIATIONS; RADIOTHERAPY; RECOILS; SIMULATION; TARGETS; TRANSPORT

Citation Formats

Johnson, Carl Edward, De Witt, Joel M, Benton, Eric R, Yasuda, Nakahiro, and Benton, Eugene V. LET spectrum measurements in Cr-39 PNTD with AFM. United States: N. p., 2010. Web.
Johnson, Carl Edward, De Witt, Joel M, Benton, Eric R, Yasuda, Nakahiro, & Benton, Eugene V. LET spectrum measurements in Cr-39 PNTD with AFM. United States.
Johnson, Carl Edward, De Witt, Joel M, Benton, Eric R, Yasuda, Nakahiro, and Benton, Eugene V. Fri . "LET spectrum measurements in Cr-39 PNTD with AFM". United States. https://www.osti.gov/servlets/purl/1026830.
@article{osti_1026830,
title = {LET spectrum measurements in Cr-39 PNTD with AFM},
author = {Johnson, Carl Edward and De Witt, Joel M and Benton, Eric R and Yasuda, Nakahiro and Benton, Eugene V},
abstractNote = {Energetic protons, neutrons, and heavy ions undergoing collisions with target nuclei of varying Z can produce residual heavy recoil fragments via intra-nuclear cascade/evaporation reactions. The particles produced in these non-elastic collisions generally have such extremely short range ({approx}< 10 {mu}m) that they cannot be directly observed by conventional detection methods including CR-39 plastic nuclear track detector (PNTD) that has been chemically etched for analysis by standard visible light microscopy. However, high-LET recoil fragments having range on the order of several cell diameters can be produced in tissue during radiotherapy using proton and carbon beams. We have developed a method to analyze short-range, high-LET tracks in CR-39 plastic nuclear track detector (PNTD) using short duration chemical etching ({approx}< 1 {mu}m) followed by automated atomic force microscope (AFM) scanning. The post-scan data processing used in this work was based on semi-automated matrix analysis opposed to traditional grey-scale image analysis. This method takes advantage of the 3-D data obtained via AFM to achieve robust discrimination of nuclear tracks from other features. Through automation of AFM scanning, sufficient AFM scan frames were obtained to attain an LET spectrum spanning the LET range from 200-1500 keV/{mu}m. In addition to our experiments, simulations were carried out with the Monte Carlo transport code, FLUKA. To demonstrate this method, CR-39 PNTD was exposed to the proton therapy beam at Loma Linda University Medical Center (LLUMC) at 60 and 230 MeV. Additionally, detectors were exposed to I GeV protons at the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL). For these exposures CR-39 PNTD, Al and Cu target foils were used between detector layers.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 2010},
month = {Fri Jan 01 00:00:00 EST 2010}
}

Conference:
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