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RESEARCH DIRECTED TOWARD THE STUDY OF THE RADIATION DAMAGE THRESHOLDS OF THE ELEMENTS
GENERAL ELECTRIC CO SCHENECTADY N Y
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The variation of the cros setion for atomic splacement, Esigma sub d, has been measured as a function of bomaing elecron energy in the ange from 0.5 to 1.3 Mev for Cu, Fe, Ni, Ag, and al. The EIGMA SUB D CURVE FOR COPPER AGREES WITH PREVIOUS MEASUREMENS, BUT APPEAS TO SAGREE WITH THE RECENT MACHINE CALCULATIONS OF THE Brookhaven group. For U, Ni, and Fe the present results, coupled wth previous neutronAMAGE DAA, SUGGEST THAT THE BASIC DAMAGE PROCESSES ARE EQUIVALENT BOTH FOR LOW AND HIGH RECOIL ENERGIES. The g reults confim directly that the threshold energy increases with inreasing atomic nber in the series Cu, Ag, and Au. All the ESIGMA UB D TA WTH THE EXCEPTION OF AL CAN BE FTTED WITH CURVES CALCULATED FROM SIMPLE THRESHOLD FUNCTIONS. The following values of effective threshold energy re found Cu--22 ev, g--28 ev, Ni--24 ev, and Fe--24 ev. the corresponding approximte vues for the resiivities of Frenkel pirs are cu--1.3 mirohm-cmat-, g--1.4 mrohm-at-, NI--. MROHM-CMAT-, and Fe--12.5 microhmat-. The ESIGMA UB D DATA FOR AL DO NOT FIT CURVES CALULATED FROM SIMPLE THRESHOD FUNCIONS, AND THIS S INTERPRETED AS EVIDENCE FOR MUTIPLE DEFECT PRODUION IN THE ANGE OF BOARING ENERGIES SED. Author
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