Br82mand Its Decay Scheme

Abstract

The discovery of a new activity of bromine is reported and is assigned to a 2(-) isomeric state of Br 82 . The new activity is chemically identified as bromine and shown to be the short-lived parent of Br 82 . It decays primarily by a highly converted M3 transition (a = 382=fc:75) of 46 keV to the 5(-) ground state of Br 82 . Two weak branches in the proposed decay scheme lead by beta emission to the 0.78-MeV level (0.15%) and the 1.48-MeV level (0.024%) of Kr 82 . Time-dependent gamma spectra, obtained with a large anticoincidence counter, demonstrate the growth of the 2.65-MeV sum peak of Br 82 after thermal-neutron activation of NEUBr. Short-lived gamma peaks at 46 keV, 0.78 MeV, and 1.48 MeV were observed in the gamma spectra of an activated sample of enriched NKUBr (99.32% Br 81 ). X-ray spectra of activated NEUBr taken with an argon-methane proportional counter provide evidence that the short-lived component is a thermal-neutron activation product. One-component decay curves of the Br K x rays over more than 6 halfperiods define the half-life of Br 82w as 363 ±2 sec.

Study of the level structures of80Br and82Br using the thermal neutron capture reaction

“…The character of the M3 transition of the isomeric state is identified from our conversion electron measurement. These results are in close agreement with previously assigned spin values [1,39,40].…”

“…Its spin and parity are 2-and 1 + respectively. They were known from the study of the decay of SZmBr and SZgBr [39,42] and from the (d,p) reaction. Our results from the conversion electron measurements are in good agreement with these assignments.…”

“…In order to normalize the conversion coefficients, the conversion coefficient of the 29keV was assumed to have a theoretical value of a E1 transition deduced from comparison of the (d, p) reaction with the results of the study on the decay of S2mBr by Oswald [39] and with results given by Lemming and Auble [40]. The results of the measurements are listed in Table 3.…”

Production of 38K Using the 35Cl(α, n)38K Reaction

“…One of the major findings in these studies has been the recognition of 'Isotope effect' between 82 Br, 80m Br and 80 Br atoms [6][7][8][9]. Following the discovery of a new isomer of 82 Br (i 1/2 = 6.2 min) in 1965 [11,12], the interest in the field was renewed and various observations have been re-evaluated in the light of 82m Br (I. T.) 82 Br process. The collection behaviour of recoil bromine species and the 'isotope effect' between bromine atoms under thermal neutron activation of alkyl-bromide systems have been explained [6][7][8][9][10] in the light of charged-species produced following capture event [13 -15] and their subsequent neutralisation during transit through the medium.…”

Nature of (η, γ) and (I.T.)-Activated Bromine Reactions in Liquid Isomers of Hexane

“…The recently discovered 82m Br (6.1 min.) [2,3] accounts for nearly 91% of total 82 Br in reaction systems and thus 82 Br data gathered in the past were produced by (mainly) isomeric transition rather than by radiative neutron capture. Many hypotheses have been made regarding the mechanism and underlying causes of reactions of bromine activated by nuclear transformations in the liquid state.…”