A device currently being tested will reveal what kind of neutron energy spectrum astronauts are exposed to from neutrons inside a spacecraft, alerting the occupants when dangerous levels occur.

"When spacecraft travel through a variety of primary high-energy cosmic rays, large vehicles absorb those rays and convert them into neutrons," said Dr. Richard Maurer, a researcher on the National Space Biomedical Research Institute's (NSBRI) technology development team. "The spacecraft's thick structure, in a sense, multiplies the primary particles so that there are more neutrons trapped inside a craft than the original number of cosmic rays that created them."

The project's goal is to develop a device that is lightweight and portable that could be transferred from the transport craft to a habitation facility or wherever it is needed. Currently, there is no compact, portable, real-time neutron detector instrument available for use inside a spacecraft or on planetary surfaces.

"These types of measurements would be crucial for exploration missions outside Earth's orbit where there is no protection from Earth's magnetic field," Maurer said.

Primary radiation particles, ranging from infrared photons to galactic cosmic rays, have been measured for years, but neutrons have not been measured adequately particularly at high energy. Instruments used to measure radiation often miss the secondary neutrons, which astronauts are also exposed to. Maurer said the estimates of the radiation that astronauts receive from neutrons account for about one-third of the actual total dose.

"Since neutrons do not carry any electrical charge, they are both harder to detect and can penetrate more deeply into a space traveler's body prod
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Contact: Liesl Owens
lkowens@bcm.tmc.edu
713-798-7595
National Space Biomedical Research Institute
11-Nov-2003