This is the seventeenth quarterly report on our echelle project, as numbered above. Our work this quarter has to some extent been directed towards the Spectroscopy Symposium held at Argonne National Laboratory on February 15, 16, and 17. This report consists principally of brief abstracts of the two papers given at this meeting. Progress since the last quarterly report included completion of the echelle comparator calibration, and the successful production and photographing of the desired spectra of praseodymium and erbium in strong magnetic fields. Considerable interest was aroused by these papers, not only because rare earth spectra are being analyzed, but because of the general applicability of our experimental techniques in producing the spectra.

The kinetics of transformation of zirconium binary alloys is being pursued. Mechanical property variation as a function of transformation if also being investigated. Zirconium-tin and zirconium-titanium alloys transform very rapidly when quenched from the beta field. These alloys have, generally speaking, been demonstrated to be not amenable to heat treatment in the normal sense of the word. Eutectoid alloys, principally zirconium-molybdenum alloys, have shown a definite response to heat treatment in terms of mechanical property variation. An embrittling agent, probably "omega" phase, is suspect at this time for the brittleness observed in certain molybdenum alloys and the very high hardness levels reached in other alloys such as zirconium-niobium and zirconium-thorium. Work to establish the existence of omega phase is in progress and, it is hoped, suggestions for avoiding the brittle condition associated with it will be forthcoming.