Radioactive isotopes are most frequently used as primary positron sources for low energy positron beam systems. In order to obtain optimum positron beam conditions, small source diameters with high intensities are desirable. Two different types of sources were prepared and investigated. 58Co was produced in a nuclear reactor via the reaction 58Ni(n; p)58Co. The bulk material was chemically separated and the 58Co was electrochemically deposited on a 1 mm diameter gold surface. The other type of source was obtained from sodium-acetate, which is commercially available. The solution was deposited on various surfaces. The prepared sources were investigated regarding the influence of inactive carrier material, internal and capsule absorption as well as backing materials by direct measurements of the positron energy spectra using a PIN-diode. In order to avoid the problem of handling very high activities, which should be applicable in these preparations, inactive material was added to simulate the absorption processes in the source.    «

Radioactive isotopes are most frequently used as primary positron sources for low energy positron beam systems. In order to obtain optimum positron beam conditions, small source diameters with high intensities are desirable. Two different types of sources were prepared and investigated. 58Co was produced in a nuclear reactor via the reaction 58Ni(n; p)58Co. The bulk material was chemically separated and the 58Co was electrochemically deposited on a 1 mm diameter gold surface. The other type of...    »