urn:nasa:pds:context:instrument:lp.aps 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 ALPHA PARTICLE SPECTROMETER Spectrometer not applicable not applicable Instrument Overview =================== The Lunar Prospector Alpha Particle Spectrometer (APS) consists of five pairs of 3 cm by 3 cm square ion-implant silicon detectors, each pair placed on one face of a cube. They are covered by thin, Al-coated polypropylene foils to exclude sunlight. The sensors have a spectral resolution of about 100 KeV at 5.5 MeV. The combined field-of-view for the 5 sensor pairs is nearly 3-pi steradians, with the only blind spot being in the direction of the spacecraft bus. The APS has a mass of 4 kg and uses about 7 w of power [BINDERETAL1998]. Science Objectives ================== A major science objective of the Alpha Particle Spectrometer is measure the number and distribution of transient lunar outgassing events and their role as sources of the tenuous lunar atmosphere. The experiment will investigate possible correlations of outgassing events with locations of young impact craters and tectonic features. Platform Mounting Descriptions ============================== The APS is mounted on one of the three Lunar Prospector booms. The Alpha Particle Spectrometer is mounted on a chassis that is shared with the Neutron Spectrometer. Operational Considerations ========================== The APS searches for gas release events by detecting alpha particles produced by the decay of gaseous Rn-222 and solid Po-210. Operation and Sampling Modes ============================ The Alpha Particle 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 Alpha Particle Spectrometer experiment is Dr. William Feldman of Los Alamos National Laboratory.