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Photonuclear Yields of N17

Daryl Reagan*

  • High-Energy Physics Laboratory, Stanford University, Stanford, California

  • *Now at the University of California Radiation Laboratory, Livermore, California.
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Phys. Rev. 100, 113 – Published 1 October, 1955

DOI: https://doi.org/10.1103/PhysRev.100.113

Abstract

Yields of N17 from several elements have been measured as functions of electron energy and converter thickness for bombardments from the Stanford linear electron accelerator. After correction for the electron-produced part of the yield, the O18(γ, p) and F19(γ, 2p) yields can be fitted (within statistics) to isochromats characteristic of 25- and 40-Mev photon energies, indicating integrated cross sections of 0.067 and 0.0037 Mev barn, respectively.

The neon and sodium yields are similar, one to the other, in their energy dependence, and indicate a N17 photoproduction cross section of the order of 3×10−30 cm2 in the 100-Mev region, rising to the neighborhood of 3×10−29 cm2 at 200 Mev.

The cross sections estimated for N17 photoproduction in magnesium and aluminum rise from about 2×10−30 cm2 in the 80- to 180-Mev region to around 3×10−29 cm2 at 400 Mev.

Estimating the N17 cross section to be about 1 percent of the total photoabsorption cross section leading to A=17 isobar production at high energies gives order of magnitude agreement with photomeson cross sections. This is consistent with the idea that direct photonuclear cross sections are small at high energies, and that the large apparent photonuclear cross section is due to indirect processes involving photomesons.

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Phys. Rev. 100, 113– Published 1 October, 1955
  • Received 3 June 1955

© 1955 American Physical Society

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