Elastic Scattering of Heavy Ions by Pb206, Pb207, and Pb208

The angular distributions of C12, N14, O16, and Ne20 elastically scattered by Pb206, Pb207, and Pb208 have been measured at laboratory energies of approximately 10.4 MeV/nucleon. The elastically scattered ions were recorded in photographic emulsions at laboratory angles from 17° to 175°. In general, measurements were extended only to angles where the ratio of the cross section to the Coulomb cross section, σσc, was greater than 0.2. In one case, the measurement was extended to a region where σσc≤1.2×10−5. The cross sections all exhibited a behavior similar to that previously reported for the same ions on Au197 and Bi209. Excellent agreement with the semiclassical strong absorption model was obtained. Nuclear interaction distances calculated by fitting the strong absorption calculations are consistent with r0=1.45 F, where R=r0(A11/3+A21/3). Reprinted from THE PHYSICAL REVIEW, Vol. 127, No. 4, 1224-1229, August 15, 1962. DOI: http://dx.doi.org/10.1103/PhysRev.127.122

Cosmic-ray Heavy Nuclei at Geomagnetic Latitude 42°N

The flux of primary cosmic ray heavy nuclei has been measured with a sandwich of C.2 and G.5 emulsions near the coast of Georgia, magnetic latitude 42°N. The emulsions were exposed at about 122 000 ft for 7.5 hours and the calculated fluxes at the top of the atmosphere in particles/ m2-sec-sr were found to be: Li, Be, B (L nuclei) 1.15.±0.3 C,N,O,F (M nuclei) 3.97±0.4 z≥10 (H nuclei) 1.29±0.3 This flight took place on May 25, 1960, near sun spot maximum. Evidence of solar modulation of the primary cosmic ray flux is shown