Development of technology for producing nickel-gallium cyclotron targets by galvanic methods

Full text: At present radioactive nuclides and their radioactive preparations are widely applied in various branches of science and technique. The present investigation is aimed at study of the opportunities for gallium-nickel cyclotron targets production. These targets should be utilized for production of cobalt-57 and germanium-68. These two isotopes have medical and commercial value. Generally Germanium - 68 is used as a calibrating source for positron emission tomography (PET). PET becomes an admitted agent for the diagnosis of cardiac, neurologic and oncologic diseases in clinical practice. Every PET instrument should be calibrated by a source, containing positron emitter. Besides, each clinical scanning should be accompanied by careful scanning of 'transmission' to receive correct interpretation of image. Germanium- 68 decays on gallium - 68 which is the positron emitter. The long half-life of germanium -68 (271 day) and its disadvantage caused by single photon emission makes its an ideal as isotope for this calibration and source of transmission. Actually any other isotope does not come nearer to its opportunity and safety for these applications. Now every PET camera uses this isotope as a sources of transmission and, with rapidly growing demand propagation in use of this technology, the inquiry on 68Ge for these sources extends. Therefore the generator 68Ge - 68Ga represents a major interest for a positron emission tomography due to unique accuracy and informativity. Electrochemical deposition of metals is widely used in cyclotron technology for producing of cyclotron targets. The given method has the following advantages: 1. This method is relatively cheap. 2. The opportunity to receive high purity metallic coating as, in many cases, at electrochemical deposition of metals there is additional purification (refining) of settled metals. Thus the bulk of impurities remains in electrolyte solution. Selecting compositions of electrolyte and conditions of deposition, in many cases, it is possible to achieve very high-purity of some settled metals. This effect has a huge technological value as allows to avoid some additional impurities of undesirable isotopes. In turn the effect of refining of superimposed metals allows to a yield a radionuclide with very high radiochemical purity. 3. The electrochemical method allows to adjust very precisely both thickness of a covering, and physical properties of covering - density of a settled covering and its crystal structure. Besides, it is necessary to underline that on the contrary to other methods of producing of cyclotron targets, the electrochemical method does not require the complex of expensive instrumentation. We had explored various systems for gallium - nickel cyclotron targets productions. Systems for deposition of two-layer gallium - nickel targets, and conditions of deposition of gallium basic layer and coating nickel layer were selected. The requirements for reliable production of the two-layer cyclotron target with adjustable thickness of gallium and nickel layers were determined. Received results allow to develop technological parameters for production of gallium - nickel cyclotron targets. (author)