Other
Scientific paper
Sep 1997
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997nasa.repts....d&link_type=abstract
Technical Report, NASA-CR-205321; NAS 1.26:205321
Other
Neutron Spectra, Monte Carlo Method, Regolith, Mars Surface, Neutron Sources, Leakage, Moisture Content, Soils, Polyethylenes, Hydrogen, Water, Experimentation, Data Correlation, Neutron Counters, Energy Spectra, Cosmic Rays
Scientific paper
The purpose of the research is to combine experiments and Monte Carlo transport of neutrons through volume of soil in an attempt to model neutron leakage from planetary surfaces. Emphasis is given to the change of neutron spectra as a function of water content and location. During the first stage of effort, two experiments were conducted in which leakage of neutrons from a Pu-Be source through about 30 g/cm2 of soil were measured with several counters. A Monte Carlo code, MCNP, has been used to model many of the 100 individual runs of the experiment. Hydrogen is the element that has the most dramatic effect on the neutron spectrum and its effect on the neutron spectrum is almost the same whether it is in the form of water or polyethylene. In order to simulate various water configurations, sheets of polyethylene have been used between layers of soil as well as water in several concentrations up to 18%. Comparison of experimental results to theoretical predictions made with the MCNP code were disappointing for low concentrations of water. We have made extensive calculations to see if room return could be the cause of the discrepancies. Water concentrations of the 'dry' soil were measured by two different laboratories and differed only by 0.5%. We have made calculations to optimize the next experiment and are investigating other methods of determining the water content of 'dry' soil.
No associations
LandOfFree
Assay of the Martian Regolith with Neutrons does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Assay of the Martian Regolith with Neutrons, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Assay of the Martian Regolith with Neutrons will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1294063