Remote analysis of surfaces by neutron-gamma-ray inelastic scattering technique

Abstract

Reversing the procedure of a number of years' work in the determination of the cross sections for production of • rays by 14-Mev neutrons interacting in pure elements, we have been studying the feasibility of applying our techniques to the remote chemical analysis of unknown materials. We have measured the spectra of • rays produced by neutrons in a large sandpile containing various known percentages of the elements O, Mg, A1, Si, and Fe.A general statement can be made that a 5 per cent abundance of any of these elements can be quantitatively determined to a precision of better than 10 per cent. The method, using fast gating and timing circuits to select only the • rays originating unambiguously from the neutron inelastic scattering process, appears so promising that a miniature, pulsed accelerator is now being tested and packaged. Applications to the analysis of the lunar surface, planetary atmospheres, and the earth's crust and mantle are discussed.

Analytical Instrumentation in Space Expoloration

“…E. F. Martina and C. D. Schrader in 1960 (15) . The technique employed in this investigation and in succeeding investigations (16,17) was neutron inelastic scattering.…”

Simultaneous Determination of Oxygen and Silicon in Meteorites and Rocks by Nondestructive Activation Analysis with Fast Neutrons.

“…For example, with longer irradiations, aluminum and silicon in rocks may be determined by counting Mg27 and Al28 (1), and magnesium and iron in meteorites may be determined by counting Na24 and Mn56. Thus, it seems feasible to apply the present method to the nondestructive analysis of the major constituents in materials similar to meteorites and rocks, such as the moon's crust (7,10,11). Methods to measure the average fast and thermal neutron flux to which an analytical sample is exposed during activation are discussed and evaluated.…”