The Gamma-Radiation from Boron Bombarded by Protons

Employing a Wilson cloud chamber we have determined the distribution in energy of pairs and recoil electrons ejected from lead and carbon laminae by the gamma-radiation from boron bombarded by protons. Both the pair and electron distributions indicate three prominent gamma-ray components at 4.3±0.3 Mev, 11.8±0.5 Mev, and 16.6±0.6 Mev with relative intensities of 1: 1: 1/7, respectively. The radiation is believed to result from proton capture by B11 to form an excited state of C12 which radiates in a single transition to the ground state or in a double transition through the well-known intermediate state at 4.3 Mev. Resonance in the yield has been found only in the region 150→200 kv and the total yield of quanta per incident proton above resonance on a thick boron target is estimated to be ≥5×10^-10

The gamma-radiation from boron bombarded by deuterons

By a method already described, the gamma-ray spectrum from B+D has been obtained by observing the positron-electron pairs ejected from a thin lead lamina (0.033 cm) and the recoil electrons from a carbon lamina (0.12 cm). Gamma-ray components with quantum energies 1.5±0.2, 2.2±0.3, 4.4±0.3, 6.9±0.4 and 9.1±0.4 Mev are indicated with relative intensities >2.5: 2.5: 1.0: 0.3: 0.1. An attempt is made to correlate the energies and relative intensities of the observed gamma-ray components with those of the proton and neutron groups

Linear accelerator project. Annual technical report, October 1, 1972-- September 30, 1973

Research on neutron cross sections and experimental and theoretical research on reactor physics and engineering are summarized. A list of theses and publications issued during the period is appended. (JFP