Internal Conversion Coefficients ofBa134,V51, andTl203

The internal conversion coefficients of ${\mathrm{Ba}}^{134}$ (parent, ${\mathrm{Cs}}^{134}$), ${\mathrm{V}}^{51}$ (parent, ${\mathrm{Cr}}^{51}$) and ${\mathrm{Tl}}^{203}$ (parent, ${\mathrm{Hg}}^{203}$) have been measured by the determination of the $\gamma$-ray yields from the Compton electron spectra produced in an external converter, employing the analysis of R. G. Thomas and T. Lauritsen and a single magnetic lens $\beta$-ray spectrometer. The ${\mathrm{Ba}}^{134}$ results involve the extension of the method to several $\gamma$-ray conversions measured simultaneously. ${\mathrm{V}}^{51}$ represents the application of the method to $K$-capture type of decay for which the direct area-under-curves method cannot be used. ${\mathrm{Tl}}^{203}$ requires the correction of the measured conversion spectrum for photoelectric conversions to obtain the pure Compton events. The values obtained for the total internal conversion coefficients are ${\mathrm{Ba}}^{134}$: 569-kev $\gamma$ ray, (9.2±1.2)×${10}^{-3\mathrm{}}$; 605-kev $\gamma$ ray, (5.3±0.5)×${10}^{-3\mathrm{}}$; 796-kev $\gamma$ ray, (2.4±0.3)×${10}^{-3\mathrm{}}$; 1.367-Mev $\gamma$ ray, (0.49±.05)×${10}^{-3\mathrm{}}$; ${\mathrm{V}}^{51}$: 325-kev $\gamma$ ray, (1.5±0.2)×${10}^{-3\mathrm{}}$; ${\mathrm{Tl}}^{203}$: 279-kev $\gamma$ ray, for $K$-shell (1.5±0.1)×${10}^{-1\mathrm{}}$, and (4.9±0.2)×${10}^{-2\mathrm{}}$ for the $L$-shell. In all cases the precision is the standard deviation. The results are in satisfactory agreement with other experimental values and with the predictions of Rose's tables.