urn:nasa:pds:context:instrument:lp.ns 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., R.C. Reedy, and D.S. McKay, Lunar neutron leakage fluxes as a function of composition and hydrogen content, Geophys. Res. Lett., 18, 2157-2160, 1991. reference.FELDMANETAL1991 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 NEUTRON SPECTROMETER Spectrometer not applicable not applicable Instrument Overview =================== A detailed description of the Lunar Prospector Neutron Spectrometer is given in the article The Lunar Prospector gamma-ray and neutron spectrometers, W. C. Feldman et al., Nuc. Inst. and Meth. A, 422, 562, 1999 [FELDMANETAL1999A]. For details not found herein, the reader is referred to this article. The Lunar Prospector Neutron Spectrometer (NS) consists of two identical 5 cm diameter by 20 cm long helium-3 filled gas proportional counters. One counter is covered with a 0.75 mm thick Cd shield, and is only sensitive to epithermal neutrons having energies above 0.25 eV. The second counter is covered with a 0.75 mm thick Sn shield and is sensitive to both thermal and epithermal neutrons. The difference in counting rates between the two counters is a measure of the flux of thermal neutrons with energies between 0 and 0.25 eV. Fast neutrons will be measured using the ACS of the Gamma Ray Spectrometer. The NS has a mass of 3.9 kg and uses about 2.5 w of power [BINDERETAL1998]. Science Objectives ================== A major science objective of the Neutron Spectrometer is to search for the existence of water ice located in permanently shadowed areas near the lunar poles. This requires separate measurements of thermal, epithermal, and fast neutrons from the lunar surface [FELDMANETAL1991]. Platform Mounting Descriptions ============================== The NS is mounted on one of the three Lunar Prospector booms. The Neutron Spectrometer is mounted on a chassis that is shared with the Alpha Particle Spectrometer. Operational Considerations ========================== Maps of hydrogen near the surface should be possible after 1 month of observations at the poles and elsewhere after 6 months of data collection. Operation and Sampling Modes ============================ The Neutron Spectrometer is designed to operate continuously during the Lunar Prospector Primary Mission. Principal Investigator ====================== The Co-I and spectrometer group leader for the Lunar Prospector Neutron Spectrometer experiment is Dr. William Feldman of Los Alamos National Laboratory.