University of Nebraska-Lincoln Detector for the Analysis of Solar Neutrons (University of Nebraska-Lincoln Detector for the Analysis of Solar Neutrons) - 11.29.17

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
The physical properties of neutrons, in particular the absence of electric charge, presents significant challenges to their detection. This is especially true for lower-energy neutrons. While no previous solar neutron detection efforts have focused on lower-energy neutrons from the sun, absorption of these slow neutrons may still be associated with radiation damage. Astronauts are particularly sensitive to low-energy neutron exposure, with adverse health consequences, and materials fatigue and degradation issues may result when spacecraft components are exposed to solar neutrons over the long term. The University of Nebraska-Lincoln Detector for the Analysis of Solar Neutrons (DANSON) project installs a new type of detector aboard the International Space Station to measure solar neutrons of lower energy. In addition to confirming decades-long predictions that the sun generates neutrons, the project investigates radiation damage and materials fatigue associated with these neutrons. A space-based approach is essential to this task, since ground-based neutron detectors are subject to interference as interactions of energetic particles with the atmosphere create secondary, non-solar neutrons.
Science Results for Everyone
Information Pending

The following content was provided by Nicole Benker, and is maintained in a database by the ISS Program Science Office.
Experiment Details

OpNom: Simple Solar Neutron Detector

Principal Investigator(s)
Peter Dowben, Ph.D., University of Nebraska-Lincoln, Lincoln, NE, United States

Elena Echeverria-Mora, University of Nebraska-Lincoln, Lincoln, NE, United States
Nicole Benker, University of Nebraska-Lincoln, Lincoln, NE, United States
Axel Enders, Ph.D., Universität Bayreuth , Bayreuth , Germany
Jennifer Hamblin, University of Nebraska–Lincoln, Lincoln, NE, United States
Yaroslav Burak, University of Nebraska–Lincoln, Lincoln, NE, United States
John McClory, Ph.D., Air Force Institute of Technology (AFIT) , WPAFB, OH, United States
Jim Petrosky , Ph.D., Air Force Institute of Technology, WPAFB, OH, United States
Jeffry Kelber, Ph.D., University of North Texas, Denton, TX, United States
Ethiyal Wilson, University of Nebraska–Lincoln, Lincoln, NE, United States
Ben Bradley, University of Nebraska–Lincoln, Lincoln, NE, United States
Scott Tarry, Ph.D., University of Nebraska Omaha, Omaha, NE, United States

University of Nebraska–Lincoln, Lincoln, NE, United States

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
Technology Demonstration Office (TDO)

Research Benefits
Earth Benefits, Space Exploration, Scientific Discovery

ISS Expedition Duration
September 2016 - April 2017

Expeditions Assigned

Previous Missions
Information Pending

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Experiment Description

Research Overview

  • Neutrons contribute to the radiation exposure of crews and must be measured to assess the exposure levels.
  • The new technology employed in the slow neutron spectrometer, the University of Nebraska-Lincoln Detector for the Analysis of Solar Neutrons (DANSON) investigation is less susceptible to false triggers from other forms of radiation and provides a clear measurement of the slow(er) neutron component in a mixed radiation environment.
  • Better insights into nucleosynthesis in the chromosphere of the sun
  • Part of the development a new type of solar telescope that detects the neutron radiation
  • Development of new power sources and power generation for deep space (trans-Jovian) vehicles.

Neutrons are difficult to detect because they are electrically neutral particles and pass through most detector systems without detection. The slow neutron spectrometer University of Lincoln-Nebraska Detector for the Analysis of Solar Neutrons (DANSON) uses a new instrument design that can significantly improve the reliability of identifying neutrons in the mixed radiation field found in deep space. This instrument design uses a moderation and capture technique that slows down the neutrons and then "captures" them in an isotope of boron. The DANSON detector uses special crystals and thin film devices loaded with the boron 10 isotope to absorb the slowed neutrons, leaving a signature in the crystal or the device of the neutron capture process. DANSON uses custom materials with distinct signatures that are easily recognized as a distinct neutron capture signal, which is then processed and analyzed to determine the radiation levels. The objective is to measure the neutron flux and neutron energy on the International Space Station (ISS) with DANSON. The ISS provides a valuable testbed for evaluating the instrument performance in a mixed radiation environment that includes sources from galactic cosmic rays, solar energetic particles, trapped radiation belts and albedo neutrons from Earth's atmosphere. The structure and contents of the ISS serve as a realistic spacecraft for exploration.

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Space Applications
Because human bodies consist largely of water and hydrocarbons, neutron radiation is a major concern for crew members, as well as some spacecraft components. Accurate measurement of the neutron environment inside space vehicles advances development of more effective radiation shielding materials and methods. An efficient and compact detector requiring no operational power is well-suited for use aboard spacecraft.

Earth Applications
Neutron sources are widely used in scientific research, as well as in medical and commercial applications. Neutron detection to identify nuclear materials used in weapons is critically important for public protection and national security. A small and sensitive slow-neutron detector is useful for neutron radiation monitoring.

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Operational Requirements and Protocols
Transfer DANSON from the launch vehicle as a softstow payload. Install DANSON on the zenith side of the ISS. DANSON will then passively absorb neutrons and requires no operation. No additional crew intervention is required until several weeks/months have passed. DANSON launched on OA-5 to the ISS. DANSON is mounted internal to the ISS and monitors neutron flux starting in Increment 49/50.

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Decadal Survey Recommendations

Information Pending

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Results/More Information

Information Pending

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Related Websites

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UNLDANSON-100 Simple-Solar-Neutron-Detector, top view. Image courtesy of University of Nebraska - Lincoln.

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