Development of the probing in-situ with Neutron and Gamma rays (PING) instrument for planetary science applications

This paper describes the testing of a prototype active neutron/gamma ray instrument for use in planetary science space applications. The Probing In situ with Neutrons and Gamma rays (PING) instrument can measure the full bulk elemental composition of a planet´s surface over a 1 m² area and down to 30-50 cm depth without the need to drill into the surface material. PING consists of three components: a pulsed neutron generator that emits 14 MeV neutrons that penetrate the surface and excite the nuclei of the planetary material; a gamma ray spectrometer that measures the energy and intensity of the gamma rays emitted by these nuclear reactions; and neutron detectors to measure the neutron moderation properties of the material. PING is tested on Earth at a unique facility near NASA/Goddard Space Flight Center where PING can be safely operated outdoors and unshielded sitting atop large (1.8m ×1.8m ×.9m), well-characterized granite and basalt monuments. We will describe both this test facility and our experiments, and present gamma ray spectroscopy results that demonstrate PING´s capabilities.