Yields of Fission-Recoil Bromine by Delayed-Neutron Studies

Abstract

target by the hot-atom reaction of the fission recoils with methane to form organic bromideso The organically-bound bromine was shown to be formed preferentially by primary (independently-formed) bromine with little contribution from secondary bromine.The delayed-neutron activity of the short-lived bromine isotopes was anaJ.yzed to obtain the relative yields of delayedneutrons from Br8?, Br88 and Br89 produced as primary fission products. The relative delayed-neutron yields are summarized below. lo2 -OolThe primary yields of the three isotopes in fission were estimated on the basis of their delayed-neutron yields.

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“…Paiss & Amiel (143) ob served the same effect in the reaction between fission iodine and methyl iodide; in this system, yields of 30 to 50 per cent were reported for primarily formed iodine atoms (100). Additional information about such reactions was obtained by Silbert & Tomlinson (141,142) who studied the formation of methyl bromide in methane.…”

“…About 10 per cent of the iodine atoms originating in the fission process itself were found to react, and to be enriched as compared to iodine atoms formed by beta decay of tellurium precursors (138). This effect was utilized for independent-yield measurements of fission iodine (137,140) and bromine (141,142). Paiss & Amiel (143) ob served the same effect in the reaction between fission iodine and methyl iodide; in this system, yields of 30 to 50 per cent were reported for primarily formed iodine atoms (100).…”

“…The same authors (141,142) used this reaction to separate 4-sec 89Br from fission products. For this purpose, methyl iodide was removed from the gas stream by reaction with solid silver nitrate and methyl bromide by adsorption in a molecular sieve (141).…”