Spectrum of Internal Bremsstrahlung fromCr51

Under favorable circumstances the spectrum of internal bremsstrahlung can be detected from $K$-capture isotopes decaying with the emission of $\gamma$ rays. The high-energy part of the ground to ground internal bremsstrahlung spectrum can be detected in ${\mathrm{Cr}}^{51}$, in the presence of 320-kev $\gamma$ rays, if suitable precautions to minimize the random superposition of small pulses are taken. A value of 780±50 kev has been found for the energy of disintegration. By using the theoretical expression of Morrison and Schiff for the intensity of the internal bremsstrahlung spectrum, a value of 7% was obtained for the percentage of disintegrations decaying to the 320-kev level of ${\mathrm{V}}^{51}$. These results are in good agreement with measurements by independent methods.