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Active neutron and gamma ray instrumentation for in situ planetary science applications
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Schweitzer, J. Namkung, M. McClanahan, T. Starr, R. Bodnarik, J. Floyd, S. Trombka, J. Evans, L. Lim, L. Parsons, A. |
| Copyright Year | 2010 |
| Description | The Pulsed Neutron Generator-Gamma Ray And Neutron Detectors (PNG-GRAND) experiment is an innovative application of the active neutron-gamma ray technology so successfully used in oil field well logging and mineral exploration on Earth. The objective of our active neutron-gamma ray technology program at NASA Goddard Space Flight Center (NASA-GSFC) is to bring the PNG-GRAND instrument to the point where it can be flown on a variety of surface lander or rover missions to the Moon, Mars, Menus, asteroids, comets and the satellites of the outer planets. Gamma-Ray Spectrometers (GRS) have been incorporated into numerous orbital planetary science missions and, especially its the case of the Mars Odyssey GRS, have contributed detailed maps of the elemental composition over the entire surface of Mars. However, orbital gamma ray measurements have low spatial sensitivity (100's of km) due to their low surface emission rates from cosmic rays and subsequent need to be averaged over large surface areas. PNG-GRAND overcomes this impediment by incorporating a powerful neutron excitation source that permits high sensitivity surface and subsurface measurements of bulk elemental compositions. PNG-GRAND combines a pulsed neutron generator (PNG) with gamma ray and neutron detectors to produce a landed instrument to determine subsurface elemental composition without needing to drill into a planet's surface a great advantage in mission design. We are currently testing PNG-GRAND prototypes at a unique outdoor neutron instrumentation test facility recently constructed at NASA/GSFC that consists of a 2 m x 2 in x 1 m granite structure placed outdoors in an empty field. Because an independent trace elemental analysis has been performed on the material, this granite sample is a known standard with which to compare both Monte Carlo simulations and our experimentally measured elemental composition data. We will present data from operating PNG-GRAND in various experimental configurations on a known sample in a geometry that is identical to that on a planetary surface. We will also illustrate the use of gamma ray timing techniques to improve sensitivity and will compare the material composition results from our experiments to both an independent laboratory elemental composition analysis and MCNPX computer modeling results. |
| File Size | 265188 |
| Page Count | 2 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20100022047 |
| Archival Resource Key | ark:/13960/t90917z82 |
| Language | English |
| Publisher Date | 2010-05-24 |
| Access Restriction | Open |
| Subject Keyword | Lunar And Planetary Science And Exploration Oil Fields In Situ Measurement Gamma Ray Spectrometers Sensitivity Space Missions Mineral Exploration Geophysics Computerized Simulation Monte Carlo Method Planetary Surfaces Neutron Counters Mars Missions Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
