urn:nasa:pds:context:instrument:lp.grs 1.0 1.11.0.0 Product_Context 2016-10-01 1.0 extracted metadata from PDS3 catalog and modified to comply with PDS4 Information Model urn:nasa:pds:context:instrument_host:spacecraft.lp instrument_to_instrument_host Binder, A.B., W.C. Feldman, G.S. Hubbard, A.S. Konopliv, R.P. Lin, M.H. Acuna, and L.L. Hood, Lunar Prospector searches for polar ice, a metallic core, gas release events, and the moon's origin, Eos, Trans. AGU, 79, 97, 1998. reference.BINDERETAL1998 Feldman, W.C., B.L. Barraclough, K.R. Fuller, D.J. Lawrence, S. Maurice, M.C. Miller, T.H. Prettyman, and A.B. Binder, The Lunar Prospector gamma-ray and neutron spectrometers, Nuc. Inst. and Meth. A, 422, 562, 1999a. reference.FELDMANETAL1999A Feldman, W.C., D.J. Lawrence, S. Maurice, B.L. Barraclough, K.R. Fuller, and R.D. Belian, Instrument Description Document (IDD) for the Lunar Prospector Spectrometers, Los Alamos National Laboratory Report LAUR-99-2752, 1999b. reference.FELDMANETAL1999B Feldman, W.C., et al., Gamma-ray, neutron, and alpha-particle spectrometers for the Lunar Prospector mission, J. Geophys. Res., 109, E07S06, doi:10.1029/2003JE002207, 2004. reference.FELDMANETAL2004 Genetay, I., S. Maurice, W.C. Feldman, O. Gasnault, D.J. Lawrence, R.C. Elphic, C. d'Uston, and A.B. Binder, Lunar neutrons at energies less than 500 keV, Planet. Space Sci., 51(3), 271-280, 2003. reference.GENETAYETAL2003 Maurice, S., W.C. Feldman, D.J. Lawrence, O. Gasnault, C. d'Uston, I. Genetay, and P.G. Lucey, High-energy neutrons from the Moon, J. Geophys. Res., 105, 20365-20375, 2000. reference.MAURICEETAL2000 GAMMA RAY SPECTROMETER Spectrometer not applicable not applicable Instrument Overview =================== A preliminary description of the LP-GRS sensor is given by FELDMANETAL199A and FELDMANETAL1999B, and a more detailed description is given by FELDMANETAL2004. For details not found herein, the reader is referred to the above mentioned manuscripts. The Lunar Prospector Gamma Ray Spectrometer (GRS) sensor consists of a 7.1 cm diameter by 7.6 cm long bismuth germanate (BGO) crystal, placed within a 12 cm diameter by 20 cm long, borated-plastic anticoincidence shield (ACS). Both scintillators are viewed by separate photomultiplier tubes, and enclosed in a cylindrical, graphite-epoxy housing. The GRS has a mass of 8.6 kg and uses about 3 w of power [BINDERETAL1998]. Science Objectives ================== The GRS will estimate the global surface abundances of key elements (U, Th, K, O, Si, Mg, Fe, Ti, Ca, Al, and H). The GRS will provide new constraints on the bulk composition of the crust, on compositional variations over the lunar surface, and on the existence of lunar resources. The GRS will investigate how large-scale impacts and volcanism have modified the structure and surface composition of the lunar crust. Platform Mounting Descriptions ============================== The Gamma Ray Spectrometer is mounted on one of the three Lunar Prospector booms. Operational Considerations ========================== The sensor housing is wrapped with a thermostat controlled heater within a thermal blanket that will provide a stable operational environment of -28 deg C for at least 1.5 years. The ACS functions to tag penetrating charged-particle events from the gamma ray spectrum and to tag gamma rays that escape from the BGO. The ACS also detects neutrons using the boron content of the shield. Operation and Sampling Modes ============================ The Gamma Ray Spectrometer is designed to operate continuously during the Lunar Prospector Primary Mission. It acquires a spectrum every 32 seconds. The gamma ray energy range of the instrument covers 0.3 to 9 MeV with a sampling resolution of 17.6 keV. The Lunar Prospector GRS, as a function of energy, is 2 to 8 times more sensitive than the Apollo gamma ray spectrometer. Principal Investigator ====================== The Co-I and spectrometer group leader for the Lunar Prospector Gamma Ray Spectrometer experiment is Dr. William Feldman of Los Alamos National Laboratory.