Search for a Long-Lived Density Isomer of 99Mo Half-Life Measurements

V. S. Butsev, G. L. Butseva, D. Chultem, P. I. Golubev, D. Kiss, E. J. Langrock, R. Ja Zulkarneev

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Experiments have been carried out aimed at the high-precision measurement of the half-life of the molybdenum nuclide 99Mo produced in reactions involving collisions of relativistic carbon nuclei with tantalum nuclei (181Ta) at an energy of 44 GeV for the purpose of detecting the possible formation of a long-lived density isomer as a result of nuclear matter compression. The experimental technique used is based on a comparison of the half-lives of the same isotope 99Mo formed in different reactions in which considerable transfers of both energy and momentum occur, namely: 98Mo(n, γ)99Mo, 235U(n, f)99Mo and 181Ta(12C, X)99Mo. It has been found that the 99Mo half-life obtained in the deep spallation reaction induced by relativistic carbon nuclei differs from the values measured in the reactions of radioactive absorption of slow neutrons and in the fission reaction; in particular, the following values of the 99Mo half-life have been obtained: (66.0197 ± 0.0877) h for the reaction 98Mo(n, γ)99Mo, (65.8467 ± 0.1052) h for the reaction 235U(n, f)99Mo, (64.9234 ± 0.2516) h for the reaction 181Ta(12C, X)99Mo. The authors believe that the difference between the half-life values obtained in the experiments may provide evidence for the formation of a long-lived density isomer at a high energy transfer. However, the authors note that these first positive results of searching for density isomers are preliminary ones which should hopefully be confirmed in further experiments. The investigation has been performed at the Laboratory of High Energies, JINR.

Original languageEnglish
Pages (from-to)227-236
Number of pages10
JournalActa Physica Hungarica New Series Heavy Ion Physics
Issue number3
Publication statusPublished - Dec 1 1998


ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy(all)

Cite this

Butsev, V. S., Butseva, G. L., Chultem, D., Golubev, P. I., Kiss, D., Langrock, E. J., & Zulkarneev, R. J. (1998). Search for a Long-Lived Density Isomer of 99Mo Half-Life Measurements. Acta Physica Hungarica New Series Heavy Ion Physics, 8(3), 227-236.