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Title: A system to measure isomeric state half-lives in the 10 ns to 10 μs range

The Isomeric State Measurement System (SISMEI) was developed to search for isomeric nuclear states produced by fusion-evaporation reactions. The SISMEI consists of 10 plastic phoswich telescopes, two lead shields, one NaI(Tl) scintillation detector, two Compton suppressed HPGe γ-ray detectors, and a cone with a recoil product catcher. The new system was tested at the 8 UD Pelletron tandem accelerator of the University of São Paulo with the measurement of two known isomeric states: {sup 54}Fe, 10{sup +} state (E = 6527.1 (11) keV, T{sub 1/2} = 364(7) ns) and the 5/2{sup +} state of {sup 19}F (E = 197.143 (4) keV, T{sub 1/2} = 89.3 (10) ns). The results indicate that the system is capable of identifying delayed transitions, of measuring isomeric state lifetimes, and of identifying the feeding transitions of the isomeric state through the delayed γ-γ coincidence method. The measured half-life for the 10{sup +} state was T{sub 1/2} = 365(14) ns and for the 5/2{sup +} state, 100(36) ns.
Authors:
 [1] ;  [2] ; ; ; ; ; ;  [1] ;  [3] ;  [4]
  1. Institute of Physics, University of São Paulo, C.P. 66318, 05315-970 São Paulo, São Paulo (Brazil)
  2. (Brazil)
  3. Fluminense Federal University, 24220-900 Niterói, Rio de Janeiro (Brazil)
  4. Universitary Center of FEI, 09850-901 São Bernardo do Campo, São Paulo (Brazil)
Publication Date:
OSTI Identifier:
22308674
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 7; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; COINCIDENCE METHODS; COMPTON EFFECT; FLUORINE 19; GAMMA DETECTION; HALF-LIFE; HIGH-PURITY GE DETECTORS; IRON 54; ISOMERIC NUCLEI; KEV RANGE; LEAD; NAI DETECTORS; PELLETRON ACCELERATORS; RECOILS; SHIELDS; TANDEM ELECTROSTATIC ACCELERATORS; TELESCOPES; THERMONUCLEAR REACTIONS