PDS_VERSION_ID                = PDS3
RECORD_TYPE                   = STREAM

OBJECT                        = INSTRUMENT
INSTRUMENT_HOST_ID            = LP
INSTRUMENT_ID                 = APS

OBJECT                        = INSTRUMENT_INFORMATION
INSTRUMENT_NAME               = "ALPHA PARTICLE SPECTROMETER"
INSTRUMENT_TYPE               = SPECTROMETER
INSTRUMENT_DESC               = "

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.  "
  
 END_OBJECT                    = INSTRUMENT_INFORMATION
  
 OBJECT                        = INSTRUMENT_REFERENCE_INFO
   REFERENCE_KEY_ID            = "BINDERETAL1998"
 END_OBJECT                    = INSTRUMENT_REFERENCE_INFO
  
END_OBJECT                    = INSTRUMENT
END