EXPERIMENTAL AND CALCULATED CROSS-SECTIONS FOR THE Bi$sup 209$ (p, xn) Po REACTION AT A PROTON BOMBARDING ENERGY OF 135 MEV (in Russian)
The cross-sections for the formation of the isotopes Po/sup 200/ to Po/ sup 200/ were determined experirmentally. The Po samples were prepared by electrodeposltion from HCl onto polished silver dishes. The alpha -activity was measured on a 31channel ionization chamber. The intensity of the alpha -ltnes was compared with the intensity of the Po alpha -line, and the relative yields wvere obtained from tte known ratios ot the probability of alpha -decay to E-capture from the various polonium isotopes. The relative yields of Po isotopes undergoing E-capture primarily were determined on a 4 pi -scintillation counter from the activity of daughter products of Po such as Bi, Pb, and Tl which were isolated radiocheimcally. An internal standard was used to correct for cheraical yield. The yield of Po/sup 200/ and Po/sup 201/ were cor rected wlth respect to the yield of Po/sup 203/, the yield of Po/sup 203/ with respect to the yield of Po/sup 205/, and the yield of Po/sup 205/ with respect to the yield of Po/sup 206/ . The absolute cross-section the Bi/sup 219/(p,4n)Po/sup 200/ reaction was measured from the yield of the A/sup 127/(p,3pn)Na/sup 24/ reaction. The experimental cross sections were compared wvith theoretical values obtained from calculations on a digital computer with the use of Mionte Carlo method (1170 proton coll1sions with the nucleus were calculated). A "cascade-evaporative" model was assumed. The density of the nuclear levels was demined on the basis of a Fermi-gas model. The calcul fission cross-section for Bi bombarded with 135- Mev tons was found to be 95 plus or minus 13 mb. This value is in good agreement with a fission cross-section of about 80 determined radiochemically by Jodra, and with a crossection of about 125 mb determined by Steiner in an ionization chamber. (TTT)
- Research Organization:
- Khlopin Radium Inst., Academy of Science, SSSR
- NSA Number:
- NSA-16-002522
- OSTI ID:
- 4818065
- Journal Information:
- Doklady Akad. Nauk S.S.S.R., Journal Name: Doklady Akad. Nauk S.S.S.R. Vol. Vol: 140
- Country of Publication:
- Country unknown/Code not available
- Language:
- Russian
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