Production of At$sup 209$ and At$sup 207$ by Bombarding Bi and Pb by High Energy Protons; OBRAZOVANIE At$sup 209$ I At$sup 207$ PRI BOMBARDIROVKE Bi I Pb PROTONAMI VYSOKIKH ENERGII
- Min Nam Buk
In bombarding bismuth and lead with 120 to 660 Mev protons, the ratios of At/sup 209/At/sup 211/ and At/sup 207/At/sup 211/ isotope yields were determined. Using chemical methods, the astatine was separated, while the relatlve yields were obtained from the L particle spectra measured by means of s grid ionization chamber. In irradiating bismuth with 120 to 660 Mev protons the ratio of the At/sup 209/At/sup 211/ yields was found to be 0.84 plus or minus 0.06 and 0.72 plus or minus i 0.06, while the ratio of the At/sup 207/At/sup 211/ yields were 0.30 plus or minus 0.03 and 0.51 plus or minus 0.04. In bombarding lead with 200 and 660 Mev protons, as well as with 400 Mev deuterons the following values of At/sup 209/At/sup 211/ ratio were obtained: 1.31 plus or minus 0.28, 1.43 plus or minus 0.43, and 1.32 plus or minus 0.25. As for the At/sup 207/At/sup 211/ ratio, it equals: 0.28 plus or minus 0.07, 0.81 plus or minus 0.13, and 0.52 plus or minus 0.15, respectively. The astatine isotopes are regarded as being produced in the secondary reactions in which the over-Coulomb He/sup 3/, He/sup 4/ and lithium nuclei due to many particle interactions involving high energy nucleons are captured. The energy spectra of the captured fragments with energies from 20 to 30 up to 100 Mev were determined qualitatively from the calculations of the yields of the observable reactions ( alpha ,2n), ( alpha ,4n), and ( alpha ,6n) on Bi and some reactions from (Li/sup 6/,n) to (Li/sup 7/,8n) on Pb. The fragment spectra in both cases are very much different from evaporative ones, and for Bi at 120 Mev are best described as l/E/ sup 3/. (auth)
- Research Organization:
- Joint Inst. for Nuclear Research, Dubna, U.S.S.R. Lab. of Nuclear Problems
- NSA Number:
- NSA-16-026220
- OSTI ID:
- 4824676
- Report Number(s):
- JINR-P-950
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-62
- Country of Publication:
- USSR
- Language:
- English
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