Nuclear Charge Distribution in Fission: Independent Yields ofAg112,I134, andCs138from Spontaneous Fission ofCf252

Independent yields of ${}_{}{}^{112}{}_{}{}^{}\mathrm{Ag}$, ${}_{}{}^{134}{}_{}{}^{}\mathrm{I}$, and ${}_{}{}^{138}{}_{}{}^{}\mathrm{Cs}$ from the spontaneous fission of ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$ have been measured. These nuclides were separated from metal foils which were used as collectors for fission fragments recoiling from a one-microgram ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$ source and purified radiochemically. Independent yields were calculated from a knowledge of the activities of the nuclides as a function of separation time. The yields, expressed as fractional independent yields are 0.009±0.004, 0.26±0.03, and 0.11±0.03, for ${}_{}{}^{112}{}_{}{}^{}\mathrm{Ag}$, ${}_{}{}^{134}{}_{}{}^{}\mathrm{I}$, and ${}_{}{}^{139}{}_{}{}^{}\mathrm{Cs}$, respectively. Corresponding values of $Z_p$ are 45.18, 52.14, and 53.82. These values differ from unchanged charge distribution by ∼0.45 charge units in agreement with previously measured fractional cumulative yields from ${}_{}{}^{252}{}_{}{}^{}\mathrm{Cf}$ fission.