RADI-N NEUTRON FIELD STUDY (RADI-N)
Research Area: Radiation Measurements and Shielding
Expedition(s): 19- 22
Principal Investigator(s): ● Harry Ing, Bubble Technology Industries, Chalk River,
Ontario, Canada
● Vyacheslav A. Shurshakov, Institute of Biomedical Problems,
Moscow, Russia
RESEARCH OBJECTIVES
Radi-N Neutron Field Study (RaDI-N) measures neutron radiation levels while aboard the
International Space Station (ISS). RaDI-N uses bubble detectors as neutron monitors that
have been designed to only detect neutrons and ignore all other radiation.
EARTH BENEFITS
Data provided from RaDI-N can lead
to further understanding of how
neutron radiation may damage or
mutate Deoxyribonucleic acid (DNA),
which may cause cataracts and cancer
on Earth as well as in space. While the
levels of neutron radiation are much
higher in space than on Earth, any
understanding into the way radiation
may alter DNA function is extremely
useful.SPACE BENEFITS
The RaDI-N team is confident that their
findings will provide an invaluable resource for accurate risk assessment of neutron radiation in
space. This could help reduce astronauts' exposure to radiation during future missions.
RESULTS
The Radi-N experiment, conducted during ISS-20/21 in 2009, used bubble detectors to
characterize the neutron radiation field in three locations in the US Orbital Segment (USOS) of
the ISS. The goal of the experiment was to compare the neutron dose and energy distribution in
Columbus, the US Laboratory, and the Japanese Experiment Module (JEM). The data collected
provided some important conclusions regarding neutron radiation in the ISS (Smith 2013). The
measured neutron energy distributions agreed well with previous measurements and did not
show a strong dependence on the location in the ISS. These energy distributions showed that
approximately 40% of the neutron dose measured was due to high-energy neutrons (> 15
MeV). Measurements with bubble dosimeters showed that the neutron dose received in the
sleeping quarters (in the JEM) was less than that received during daily activities around the ISS.
Furthermore, experiments with a water shield in the JEM showed that the neutron dose on the
inner side of the shield was reduced to 72% of the value on the outer side of the shield. A
follow-up experiment, Radi-N2, commenced in 2012 and is ongoing.
ISS020E050738 – Canadian Space Agency astronaut
Robert Thirsk, Expedition 20/21 flight engineer, works
with a Bubble dosimeter detector kit for the
Matryoshka-R experiment in Service Module.