An ion-exchange -- polarographic method was developed for the determination of iron(III) in Homogeneous Reactor Fuels. Copper, which interferes, is removed from the fuel by plating it onto a cadmium coil. Iron is oxidized to iron(III) by potassium permanganate, and the iron(III) is separated from interfering metal ions by ion exchange on a Dowex 1 resin column that is in the sulfate form. The iron(III) in the effluent is determined polarographically in 0.5 M sodium citrate solution as supporting electrolyte. A fairly well defined polarographic wave is obtained for the iron(III) → iron(II) reduction at a half-wave potential of approximately -0.15 v. vs. the S.C.E. The relative standard deviation of the data for 2 µg of iron(III) per ml of solution in the polarographic cell was 6.5%; for 10 µg of iron(III) per ml it was 0.6%.

The ORNL 86-in. cyclotron is being modified to provide for deflection of the proton beam. It is expected that operation will be resumed late in the spring. Nuclear physics work was limited, for the most part, to interpretation of previously collected data and to making preparations for utilizing the deflected beam. It was found that for certain isotopes the production rates could be almost doubled by operating at a slightly reduced energy and a much larger current. With the use of the ORNL 63-in. cyclotron, the absolute values of the electron capture and loss cross sections for 26-Mev nitrogen ions were obtained. The angular distribution of the cross sections for elastic scattering of nitrogen by nitrogen was measured at energies from 13 to 22 Mev. A double-focusing 90-deg magnet is being planned for use in identifying stable reaction products from nitrogen-induced reactions. The major components of the revised 44-in. test cyclotron were assembled and are being tested. Consideration is being given to the use of these components, along with a new 20,000-oersted magnet and a shielded cyclotron room, and if the tests are satisfactory the Laboratory will have available a machine which will accelerate N5+ ions to 81 Mev.