Search for X-ray induced decay of the 31-yr isomer of 178Hf using synchrotron radiation

Ahmad, I ; Banar, J C ; Becker, J A ; Bredeweg, T A ; Cooper, J R ; Gemmell, D S ; Kraemer, A ; Mashayekhi, A ; McNabb, D P ; Miller, G G ; Moore, E F ; Palmer, P ; Pangault, L N ; Rundberg, R S ; Schiffer, J P ; Shastri, S D ; Wang, T F ; Wilhelmy, J B

Lawrence Livermore National Laboratory

关键词: Advanced Photon Source;    Decay;    43 Particle Accelerators;    71 Classical And Quantum Mechanics, General Physics;    Isomers;   

DOI  :  10.2172/15011624
RP-ID  :  UCRL-TR-206598
RP-ID  :  W-7405-ENG-48
RP-ID  :  15011624

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来源: UNT Digital Library

【 摘 要 】

Isomeric {sup 178}Hf (t{sub 1/2} = 31 yr, E{sub x} = 2.446 MeV, J{sup {pi}} = 16{sup +}) was bombarded by a white beam of x-rays from the Advanced Photon Source at Argonne National Laboratory. A search was made for x-ray induced decay of the isomer by detecting prompt and delayed {gamma} rays associated with the decay. No induced decay was observed. Upper limits for such a process for x-ray energies between 7-100 keV were set. The limits between 7 and 30 keV are below {approx} 3 x 10{sup -27} cm{sup 2}-keV for induced decay that bypasses the 4-s isomer and {approx} 5 x 10{sup -27} cm{sup 2}-keV for induced decay that is delayed through this isomer, orders of magnitude below values at which induced decay was reported previously. These limits are consistent with what is known about the properties of atomic nuclei.