$mu$$sup -$-MESIC ATOMIC PROCESSES IN GASEOUS HYDROGEN
Gamma rays at 6.14, 6.91, and 7.12 Mev produced by the F/sup 19/(p, alpha gamma )O/sup 16/ reaction were used to induce heavy element fission. The photofission cross sections of Th/sup 232/ U/sup 238/, U/sup 236 U/sup 235/, U/ sup 234/, U/sup 233/, and Np/sup 237/ for a 7.0-Mev average gamma energy (a mixture of the 6.91- and 7.12-Mev gamma rays) are 9 15 28 33 52 44 and 45 mb, respectively. The cross section for producing Mo/sup 99/ from U/sup 238/ using 7.0-Mev gamma rays is 1.1 mb. The 7.0-Mev photon absorption cross section of heavy nuclei is 60 plus or minus 20 mb; the gamma strength function GAMMA (bar)/sub 0//D for heavy nuclei at 7.0-Mev is (2.5 plus or minus 0.8) x 10/sup - 4/. The variation in the photofission cross sections with 6.14-Mev photons for nuclei in which photoneutron emission is energetically forbidden is interpreted in terms of resonance absorption. This results from the line width of the 6.14- Mev photons (O/sup 16/ recoils stopped prior to the emission of the 6.14-Mev gamma ray) being of the same order as the average spacing between levels of the same spin in the compound nucleus. (auth)
- Research Organization:
- Joint Inst. for Nuclear Research, Dubna, USSR
- NSA Number:
- NSA-16-023081
- OSTI ID:
- 4822864
- Journal Information:
- Nuclear Phys., Journal Name: Nuclear Phys. Vol. Vol: 34
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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