Accession Number : AD0660038

Title :   STUDIES OF STRESS CORROSION CRACKING BY THE MOSSBAUER EFFECT.

Descriptive Note : Final technical rept. 1 Feb-31 Jul 67,

Corporate Author : MITHRAS INC CAMBRIDGE MASS

Personal Author(s) : Terrell,J. H. ; Forsyth,R. H. ; Naiman,C. S.

Report Date : 31 JUL 1967

Pagination or Media Count : 33

Abstract : An investigation into various techniques for carrying out Mossbauer effect (ME) measurements in a non-destructive, in situ manner requiring no sample preparation (backscatter ME measurements) is reported. The research was directed toward detecting the 2% abundant Fe57 nucleus which is common to iron alloys so that environmental changes brought about by stress and/or corrosion could be followed. Comparisons of three backscatter ME experiments which employ different geometrical arrangements of the source, sample, and counter and which detect the 14.4 kev gamma-rays or 6.3 kev internal conversion X-rays are given. It is found that the most efficient technique for performing backscatter ME measurements is to use a geometrical arrangement designated as 'around-the-corner' detecting 6.3 kev internal conversion X-rays. A discussion of the background count rate is given along with a description of an anti-coincidence system which can be used to significantly reduce the background but only for weak sources. (Author)

Descriptors :   (*STRESS CORROSION, *MOSSBAUER EFFECT), INTERNAL CONVERSION, X RAYS, BACKSCATTERING, GAMMA RAYS, PROPORTIONAL COUNTERS, CRACKS, SOURCES, THICKNESS, SAMPLING, GEOMETRY, REFLECTION, DETECTORS, EMISSIVITY, IRON, PHOTONS, NONDESTRUCTIVE TESTING

Subject Categories : Radiation and Nuclear Chemistry
      Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE