Monte Carlo method is an invaluable tool in the field of radiation protection, used to
calculate shielding effectiveness, as well as dose for medical applications. With few
exceptions, most of the objects currently simulated have been homogeneous materials
that vary in density by a factor of 3 or less. In the irradiation of very heterogeneous
objects, particularly layered or leafy food items, one will encounter air pockets within
the bundle as a matter of course. These pockets will cause variations in density of up
to three orders of magnitude. Air pockets in a tissue equivalent phantom were found
to produce “hot spots” in the dose distribution, and introduced significant deviations
between the calculated and measured distribution of dose to the phantom. To date,
very little published work had been done in the area of Monte-Carlo simulation of
objects of such disparate density. Before Monte Carlo methods can be used
successfully in this regime, further code development and experimental validation
will be necessary, of which this work is just a beginning. Phantoms were made of
corrugated low-Z material similar in electron density to plant based material. These
phantoms incorporated air gaps of comparable size to those found in the leafy objects
of interest. Dimensions were chosen to bracket electron ranges in the material of the objects modeled. Monte Carlo analysis will provide a reasonable qualitative picture of
the dose distribution, but such a picture is not yet sufficiently accurate in a
quantitative sense. Air gaps within the plant material produced large discrepancies
between calculation and measurement. Smaller air gaps were observed to produce
greater discrepancy between calculation and measurement.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2560 |
| Date | 15 May 2009 |
| Creators | Tutt, Teresa Elizabeth |
| Contributors | Braby, Lesie A. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | electronic, application/pdf, born digital |
Page generated in 0.0021 seconds