Dual silicon surface-barrier detectors and associated electronics for monitoring chemical separation of 249Cf and 249Bk

The isotopes 249Cf and 249Bk are chemically separated by ion-exchange chromatography at the Oak Ridge National Laboratory Transuranium Processing Plant. Control of the separation depends on the operator's ability to distinguish electronically between alpha radiation from the 249Cf and beta particles from the 249Bk. This new monitoring system consists of two surface-barrier detectors, each having its own channel of electronics and data acquisition. The two detectors are mounted in a Teflon holder and positioned near the tip of the ion-exchange column, where droplets of solution are formed as the nuclides are eluted from the column. Amplifier gain and window settings on the single-channel analyzer (SCA) for one detector are adjusted to count the energetic alpha particles from the 249Cf, while the electronic settings of the other channel are adjusted to count the lower-energy beta particles from 249Bk. The alpha count rate will increase first as 249Cf passes from the column; then the beta count rate increases, indicating that 249Bk is being eluted. At this point, the operator can make a cut in the separation process. (orig.)