DECAY OF 6.3-MIN Br$sup 7$$sup 8$

Journal Article · Fri Jul 15 00:00:00 EDT 1960 · Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D

DOI:https://doi.org/10.1103/PhysRev.119.755· OSTI ID:4158822

Pierson, W R; Coryell, C D

The nuclide 6.3-min Br/sup 78/ was made by the reactions ( gamma ,n), (n,2n), (p,n), (d,2n), and ( alpha ,n), and its decay properties were investigated by positron decay-curve analysis, by application of a standard chemical isomer-separation produre, by searching for conversion electrons, and by studyin g the gamma-ray and positron-gamma-coincidence spectra. The early portion of the positron decay curve exhibited a single 6.25 plus or minus 0.2- min component, and no active daughter of this species was chemically separable from active CBr/sub 4/. Conversion electrons were not found, and soft gamma rays were shown to be absent. There are 12-kev x rays, of intensity about 0.05 relative to the positrons and therefore presumed to be K x rays of Se resulting from electron capture. These results show that 6.3-min Br/sup 76/ has no daughter isomer and probably no>10-sec parent isomer. There is a 615-kev gamma ray, in coincidence with pcsitrons, and of intensity 0.139 that of all positrons, representing decay of Br/sup 78/ to Se/sup 78/ in the 615-kev 2+ state. However, no evidence for decay to Se/sup 78/ in the 1.32-Mev state could be found. From these data it was deduced that 6.3-min Br/sup 78/ decays 81% by positron emission and 6% by electron capture to ground-state Se/sup 78/, 11% by positron emission and 2% by electron capture to Sea in the 615-kev state, and <1% to Se/sup 78/ in the 1.32-Mev state. The disintegrations of Br/sup 78/ to Se/sup 78/ in the ground state and 615-kev state have log ft values of 4.8 and 5.2, respectively, indicating that the spin of ground-state Br/sup 78/ is 1, with even parity. The absence of isomerism is discussed in terms of the Iccations of expected energy levels with reference to the known locations of these levels in Br/sup 80/. (auth)

• Research Organization: Massachusetts Inst. of Tech., Cambridge
• NSA Number: NSA-14-022408
• OSTI ID: 4158822
• Journal Information: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D, Journal Name: Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D Vol. Vol: 119; ISSN PHRVA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ALPHA BEAMS
BROMINE 78
CAPTURE
COINCIDENCE METHODS
CONVERSION
DECAY
DEUTERON BEAMS
ELECTRONS
ENERGY LEVELS
GAMMA RADIATION
ISOMERS
MEASURED VALUES
NEUTRON BEAMS
NEUTRONS
NUCLEAR REACTIONS
ORGANIC BROMINE COMPOUNDS
PARITY
PHYSICS
POSITRONS
PRODUCTION
PROTON BEAMS
SELENIUM 78
SEPARATION PROCESSES
SPECTRA
SPIN
X RADIATION