Energy levels of Z = 11−21 nuclei (IV)

Energy levels of light nuclei. III Z = 11 to Z = 20

The experimental material on energy levels published from December 1, 1953 to February 1, 1957 is covered along with the 1954 energy level compilation STAP. M. Endt and J. C. Wuyver, Revs. Mod. Phys. 26, 95(1954)!. Little attention is given to cross-section measurements. Many particle reactions, as (n,2n) or spallation reactions, are omitted altogether. Theoretical papers are quoted only briefly. Numerous diagrams and tables and an extensive bibliography are given. (M.H.R.)

Energy Levels of Light Nuclei ( Z = 11 to Z = 20 ). II.

Internal bremsstrahlung from P32, Sr89, Y90, Y91 and Bi210

Internal bremsstrahlung from P32 and Y90

The spectral distribution and the total energy of the internal bremsstrahlung of ${\mathrm{P}}^{32}$ were measured from 20 to 1000 kev with a NaI(Tl) scintillation spectrometer. Special care was taken to diminish and correct for bremsstrahlung from the apparatus and the surroundings. The experimental curve agrees with theory from 20 to 50 kev and in the region 50-120 kev shows a weak bump in a smoothed curve; from 120 to 500 kev the curve lies 15 percent, at 800 kev 45 percent, and at 1000 kev 70 percent above a theory based on allowed $\ensuremath{\beta}$ transition; thus, above 120 kev, the experimental curve disagrees with the theory for both allowed and forbidden $\ensuremath{\beta}$ transitions. The total energy per $\ensuremath{\beta}$ decay in the internal bremsstrahlung was found to exceed the calculated value by 21 percent.Using the same experimental arrangements the external bremsstrahlung emitted when the ${\mathrm{P}}^{32}$ $\ensuremath{\beta}$ rays are completely stopped in carbon, aluminum, iron, tin, and lead was also measured. For light elements the observed spectrum was found to agree closely with the theory by Bethe and Heitler as improved by Elwert, but for heavy elements and high energies to exceed the calculated values considerably, e. g., for lead at 500 and 1000 kev by a factor of 1.4 and 2.0, respectively.

K. Lidén

Papers

Internal and External Bremsstrahlung Accompanying the Beta Rays of P 32