Independent fission yields of short-lived Br and I isotopes in thermal neutron fission of235U

A comprehensive study has been carried out of the yield pattern of fission products formed in thermal neutron-induced fission of 235 U. An isotope separator on-line a nuclear reactor was used for rapid separation of the fission products. At a target temperature of 2400 Q C all fission elements, with the exception of the little volatile transition elements zirconium, niobium, molybdenum, technetium, ruthenium, and rhodium, are released. Their isotopes are then available for study which means that a very complete mapping of the yield distribution is within reach. In the analysis the delay between production and measurement and the overall separator efficiency for three consecutive elements -the one under study and its parent and grandparentare taken into account. Independent and/or cumulative yields have been obtained for 195 nuclear species, among them 83 isomeric states.

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“…For 139 I the (independent and cumulative) value 0.57 + 0.05% is obtained as the average of the values in refs. [2,15,20,21],…”

Section: Iodine Isotopesmentioning

confidence: 99%

Yields of Products from Thermal Neutron-Induced Fission of ²³⁵U

et al. 1990

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“…One of the reasons for the low ion yields was the relatively high work function of the graphite. A negative surface ionization source with low work function material LaB 6 as the ionizer was later developed [18] and used to study the fission yields of short-lived bromine and iodine isotopes [19]. Low yields of negative radioactive ions of Br and I were also obtained from a UO 2 -graphite surface [20] for delayed neutron emission studies at the SOLAR on-line mass spectrometer facility [21].…”

Section: Introductionmentioning

confidence: 99%

Production of negatively charged radioactive ion beams

2017

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Beams of short-lived radioactive nuclei are needed for frontier experimental research in nuclear structure, reactions, and astrophysics. Negatively charged radioactive ion beams have unique advantages and allow for the use of a tandem accelerator for post-acceleration, which can provide the highest beam quality and continuously variable energies. Negative ion beams can be obtained with high intensity and some unique beam purification techniques based on differences in electronegativity and chemical reactivity can be used to provide beams with high purity. This article describes the production of negative radioactive ion beams at the former holifield radioactive ion beam facility at Oak Ridge National Laboratory and at the CERN ISOLDE facility with emphasis on the development of the negative ion sources employed at these two facilities.

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