ALPHA-GAMMA ANGULAR CORRELATION MEASUREMENTS WITH LIQUID SOURCES

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 are U/sup 232/, Th/sup 230/, and Ra/sup 226/ . Thicknesses of the soli d 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 liquid 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 0.29 450 deg C in a 0.01 for sources in which recoils were stopped in Am/sub 2/O/sub 3/, 0.20 450 deg C in a 0.01 for sources in which recoils were stopped in mica, 0.52 450 deg C in a 0.02 for sources in which recoils were stopped in gold, and 0.67 450 deg C in a 0.01 for sources in which recoils were stopped in aluminum. Unattenuated angular correlations were obtained with liquid sources containing Am/sup 243/ in 0.5 M and 1.0 M HClO/sub 4/ . For liquid sources containing Am/sup 243/ in 3.0 M HClO/sub 4/, the correlation was attenuated, with an average attenuation coefficient of 0.86 450 deg C in a 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/ = 0.75 450 deg C in a 0.05 and G/sub 4/ = 0.86 450 deg C in a 0.03 for U/sub 232/ , G/sub 2/= 0.64 450 deg C in a 0.06 and G/sub 4/= 0.84 450 deg C in a 0.04 for Th/ sup 230/, and G/sub 2/ = 0.76 450 deg C in a 0.11 and G/sub 4/ = 0.90 450 deg C in a 0.07 for Ra/sup 226/. The postulate that the measured angular correlation function for Am/sup 243/ is attenuated by the same amount as the correlation functions for the even-even nuclides is found to be untenable since it requires unreasonable alpha mixing ratios or unreasonable admixtures of M2 to E1 gamma radiation in the Am/sup 243/ decay process. The attenuation observed with even-even nuclide sources is believed to be consistent with the postulate of a time-dependent electric interaction. 81 references. (auth