November 10, 2012
Neutron Monitoring to Protect Astronauts From Radiation In Space
April Flowers for redOrbit.com — Your Universe Online
NASA scientists and engineers have been working since Neil Armstrong and Buzz Aldrin first stepped on the surface of the moon to solve the complexities of traveling to and working in space that present significant challenges to the astronauts.
One of those challenges is the space radiation that humans are subjected to when they go outside Earth's protective atmosphere and magnetic field. Plans are afoot to send astronauts farther into our solar system than ever before. This will require advanced instruments designed for monitoring and detecting radiation in space vehicles and habitats.
NASA's approach to this problem is a renewed focus on understanding radiation in space environments with the Advanced Neutron Spectrometer (ANS). The scientists aim to build a new tool to protect astronauts exploring outer space by monitoring neutrons with the ANS.
"Measuring neutrons in a space environment will keep astronauts safer because it will give mission managers on Earth invaluable information about the amount of radiation astronauts are being exposed to," said Mark Christl, the ANS project lead at Marshall. "The ANS can be used to detect the levels of radiation in the spacecraft or habitat so that astronauts can employ techniques to minimize their exposure."
Neutrons are electrically neutral particles that pass through most detector systems undetected, making neutrons difficult to monitor. A new instrument design on the ANS will significantly improve the reliability of identifying neutrons in the mixed radiation field of deep space using a gate and capture technique to slow down the neutrons and "capture" them in an isotope of Lithium. Special glass fibers are loaded with Lithium to absorb the slowed neutrons. This produces a small flash of light unique to the capture process. Custom electronics in the ANS recognize and trigger on the distinct neutron capture signal. This signal is then processed and analyzed to determine radiation levels.
A team of scientists and engineers at Marshall Space Flight Center has been developing a prototype for the ANS instrument in collaboration with the Johnson Space Center and other NASA centers. They recently shared their work with the RadWorks team from Johnson and Langley Research Center. The team at Marshall developed this novel prototype in only 11 months using radioactive sources and exposures to high-energy protons available at Indiana University Cyclotron Facility to evaluate the effectiveness of the ANS.
"Our work thus far has been very promising," said Christl. "By working closely with JSC and other NASA centers, we've been able to make great strides on some key radiation protection issues that include the ANS prototype. Our goal is to continue this work to improve the instrument performance and our radiation monitoring capabilities for our astronauts and meet the future needs of exploring new destinations."
Radworks - an Advanced Exploration Systems (AES) project that is a cross agency team led by the Johnson Space Center - developed the ANS to address radiation detection, monitoring and protection that will be needed for manned exploration beyond low-Earth orbit.