Since the beginning of space exploration in last century, several kinds of devices from passive
and active dosimeters to radiation environment monitors have been used to measure radiation
levels onboard different space crafts and shuttles allowing the space community to identify and
quantify space radiation. The recent construction of several laboratories on the International
Space Station (ISS) has confirmed that prolonged duration space missions are now becoming
standard practice and as such, the need to better understand the potential risk of space radiation
to Astronaut’s health, has become a priority for long mission planner.
The complex internal radiation environment created within the ISS is due to high-energy particle
interactions within the ISS shielded environment. As a result, a large number of secondary
particles, that pose specific health risks, are created. Neutrons are one important component of
this mixed radiation field due to their high LET. Therefore, the assessment of the neutron dose
contribution has become an important part of the safety and monitoring program onboard the
ISS. The need to determine whether neutron dose measured externally to the human body give an
accurate and conservative estimate of the dose received internally is of paramount importance for
long term manned space missions.
This thesis presents a part of an ongoing large research program on radiation monitoring on ISS
called Matroshka-R Project that was established to analyze the radiation exposure levels onboard
the ISS using different radiation instruments and a spherical phantom to simulate human body.
Monte Carlo transport code was used to simulate the interaction of high energy protons and
neutrons with the spherical phantom currently onboard ISS. A Monte Carlo model of the
phantom has been built, and it consists of seven spherical layers presenting different depths of the simulated tissue. The phantom has been exposed to individual proton energies and to a
spectrum of neutrons. The flux of the created neutrons inside the phantom has been calculated.
The internal to external neutron flux ratio was calculated and compared to the experimental data,
recently, measured on three separate expeditions of the ISS. The results from the calculations
showed that the value of the neutron fluxes inside and outside the phantom is different from the
data recently measured with bubble detectors. / UOIT
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OOSHDU.10155/135 |
| Date | 01 December 2010 |
| Creators | Tasbaz, Azadeh |
| Contributors | Machrafi, Rachid |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
Page generated in 0.0017 seconds