Internal and External Bremsstrahlung Accompanying the Beta Rays ofP32

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 $\beta$ transition; thus, above 120 kev, the experimental curve disagrees with the theory for both allowed and forbidden $\beta$ transitions. The total energy per $\beta$ decay in the internal bremsstrahlung was found to exceed the calculated value by 21 percent.