Characterizing high z high energy (HZE) particles in cosmic radiation is of importance
for the study of the equivalent dose to astronauts. Low pressure, tissue equivalent
proportional counters (TEPC) are routinely used to evaluate radiation exposures in space.
A multiple detector system composed of three TEPC of different sizes was simulated
using the Monte-Carlo software toolkit GEANT4. The ability of the set of detectors to
characterize HZE particles, as well as measure dose, was studied.
HZE particles produce energetic secondary electrons (-rays) which carry a
significant fraction of energy lost by the primary ion away from its track. The range and
frequency of these delta rays depends on the velocity and charge of the primary ion.
Measurements of lineal energy spectra in different size sites will differ because of these
delta ray events and may provide information to characterize the incident primary
particle.
Monte Carlo calculations were accomplished, using GEANT4, simulating solid
walled proportional detectors with unit density site diameter of 0.1, 0.5 and 2.5 µm in a
uniform HZE particle field. The simulated spherical detectors have 2 mm thick tissue
equivalent walls. The uniform beams of 1 GeV/n, 500 MeV/n and 100 MeV/n 56Fe, 28Si,
16O, 4He and proton particles were used to bombard the detector. The size effect of such
a detector system was analyzed with the calculation results.
The results show that the y vs. yf(y) spectrum differs significantly as a function of
site size. From the spectra, as well as the calculated mean lineal energy, the simulated
particles can be characterized. We predict that the detector system is capable of characterizing HZE particles in a complex field. This suggests that it may be practical to
use such a system to measure the average particle velocity as well as the absorbed dose
delivered by HZE particles in space. The parameters used in the simulation are also good
references for detector construction. characterizing HZE particles in a complex field. This suggests that it may be practical to
use such a system to measure the average particle velocity as well as the absorbed dose
delivered by HZE particles in space. The parameters used in the simulation are also good
references for detector construction.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-1135 |
| Date | 15 May 2009 |
| Creators | Wang, Xudong |
| Contributors | Braby, Leslie A. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | electronic, application/pdf, born digital |
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