| Abstract: | From experimental studies of gamma rays from fast and thermal neutron reactions in hydrogeneous and non-hydrogeneous, semi-infinite samples and from Monte Carlo calculations on soil of a composition which might typically be encountered on planetary surfaces, it is found that gamma rays from fast or inelastic scattering reactions would dominate the observed spectra. With the exception of gamma rays formed by inelastically scattered neutrons on oxygen, useful spectra would be limited to energies below 3 MeV. Other experiments were performed which show that if a gamma-ray detector were placed within 6 m of an isotopic neutron source in a spacecraft, it would be rendered useless for gamma-ray spectrometry below 3 MeV because of internal activation produced by neutron exposure during space travel. Adequate shielding is not practicable because of the size and weight constraints for planetary missions. Thus, it is required that the source be turned off or removed to a safe distance during non-measurement periods. In view of these results an accelerator or an off-on isotopic source would be desirable for practical gamma-ray spectral analysis on planetary surfaces containing but minor amounts of hydrogen. ?? 1974. |
| Genre: | Article |
| ProdID: | 70010172 |
| Citation Author: | Senftle, F.; Philbin, P.; Moxham, R.; Boynton, G.; Trombka, J. |
| Citation Contributing Office: | |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | |
| Citation Editor: | |
| Citation End Page: | 443 |
| Citation Issue: | 2 |
| Citation Keywords: | |
| Citation Language: | English |
| Citation Larger Work Title: | Nuclear Instruments and Methods |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | 9 |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | Elsevier |
| Citation Series: | |
| Citation Series Code: | |
| Citation Series Number: | |
| Citation Search Results Text: | Problems encountered in the use of neutron methods for elemental analysis on planetary surfaces; 1974; Article; Journal; Nuclear Instruments and Methods; Senftle, F.; Philbin, P.; Moxham, R.; Boynton, G.; Trombka, J. |
| Citation Start Page: | 435 |
| Citation Volume: | 117 |
| Citation Year: | 1974 |
| Type: | citation/reference |
| Text: | Problems encountered in the use of neutron methods for elemental analysis on planetary surfaces; 1974; Article; Journal; Nuclear Instruments and Methods; Senftle, F.; Philbin, P.; Moxham, R.; Boynton, G.; Trombka, J. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1016/0029-554X(74)90289-4 |
| Date Other: | Tue, 1 Jan 1974 00:00 -0600 |
| Publisher: | Elsevier |
