ALPHA-GAMMA ANGULAR CORRELATION MEASUREMENTS WITH LIQUID SOURCES

Abstract

Alpha-gamma angular correlation measurements were made with solid sources of Am/sup 243/ and with liquid sources containing either Am/sup 243/ or an even-even alpha emitter in dilute perchloric acid solutions. Even-even alpha emitters studied were U/sup 232/, Th/sup 230/, and Ra/sup 226/. Thicknesses of the solid sources were controlled so that the neptunium recoils from one source were stopped in Am/sub 2/O/sub 3/ while recoils from the other sources were stopped in the aluminum, gold, or mica backing on which the sources were vaporized. The light sources were films consisting of 3 microliters of solution placed between a rubber hydrochloride membrane and a microscope cover glass 1 cm/ sup 2/ in circular cross section. The perchloric acid concentration of the liquid sources ranged from 0.5 to 3.0 molar. All of the angular correlations obtained with solid Am/sup 243 sources were attenuated, the average attenuation coefficients being 0.29 plus or minus 0.01 for sources in which recoils were stopped in Am/sub 2/O/sub 3/, 0.20 plus or minus 0.01 for sources in which recoils were stopped in mica, 0.52 plus or minus 0.02 for sources in which recoils were stopped in gold, and 0.67 plus or minus 0.01 for sources in whichmore » recoils were stopped in aluminum. Unattenuated angular correlations were obtained with liquid sources containing Am/sup 243/ in 0.5M and 1.0M HClO/sub 4/. For liquid sources containing Am/sup 243/ in 3.0M HClO/sub 4/, the correlation was attenuated with an average attenuation coefficient of 0.86 plus or minus 0.01. Attenuated angular correlations were also found with liquid sources containing an even-even nuclide in dilute aqueous solutions. The average attenuation coefficients for the even-even nuclide liquid sources were G/sub 2/ = 0.75 plus or minus 0.05 and G/sub 4/=0.86 plus or minus 0.03 for U/sup 232/, G/ sub 2/=0.64 plus or minus 0.06 and plus or minus 0.11 and G/sub 4/= 0.90 plus or minus 0.07 for Ra/sup 226/. The postulate that the measured angular correlation function for Am/sup 243/ was attenuated by the same amount as the correlation functions for the eveneven nuclides was found to be untenable since it required unreasonable alpha mixing ratios or unreasonable admixtures of M2 to El gamma radiation in the Am/sup 243/ decay process. The attenuation observed with even-even nuclide sources was believed to be consistent with the postulate of a time-dependent electric interaction.« less