are totally separated from each other. The peripheral partition walls and the baffle ridges force a zigzag motion for the flowing liquid. There are two collection chambers, one above and one below the separation volume; the light phase is discharged from the upper collection chamber, whereas the heavy phase is discharged from the lower chamber. Different types of pump wheels are used for discharge. The centrifuge was constructed of pure titanium (later models have the titanium pacified with palladium that has been diffused into the titanium surface) and was driven by a pneumatic motor or a variable-speed induction motor. The central bowl volume was 120 mL, and the holdup time was about 3 s. The system gave excellent phase separation.

Figure 29. Sketch of the experimental apparatus used for on-line separation of gallium from zinc and copper activities after these had been transported to a low-background area with an HeJRT system. [Kos74; reprinted with permission from Nucl. Instrum. Methods]

Aronsson, Ehn, and Rydberg [Art70] used the H-centrifuge to achieve fast, continuous separation of 116Pd produced by 14-MeV neutron-induced fission of 238U. Figure 30 shows a schematic of the equipment they used. Uranyl nitrate (2M) in 1M nitric acid solution containing acetylacetone (0.1M) passed through the irradiation cell and a delay line and was then mixed with toluene and fed to the first centrifuge. Palladium isotopes formed in fission were complexed by acetylacetone and were extracted by toluene. The toluene phase from the centrifuge was passed through a delay line; 116Pd decayed to 116Ag during the delay. The organic phase was then mixed



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