Erection and testing of a magnet spectrometer for the velocity filter SHIP

In the framework of the present thesis a magnet spectrometer for the separation of heavy ions was constructed, erected, and tested. In connection with the velocity filter SHIP of GSI Darmstadt, the spectrometer consisting of a 300 dipole magnet and a quadrupole doublet can be used as recoil-product mass separator. As independent device with large acceptance the DQQ spectrometer can also be used with gas filling for instance for the producion of most heavy elements. The difference of the new arrangement to the hitherto operation of SHIP is that hitherto all products from fusion-evaporation reactions should be separated as possible, but now the separation of single isobaric chains for instance for detailed spectroscopy in the range of light and medium heavy nuclei is possible. An important range of application of the separator is the study of extremeously neutron-deficient nuclei with half-lives from μs to ms in regions in which the production cross sections strongly decrease with increasing neutron evaporation. The expected ion-optical properties of the DQQ spectrometer which were obtained by computer simulation of fusion experiments could be experimentally confirmed in the mass ranges around A=150 and A=100. In first applications it was shown that the methods of the in-beam spectroscopy and those of the on-line mass separators can be supplemented in the ranges of small formation cross sections and short-lived activities. By direct mass-number determination succeeded the unique assignment of the 109 μs respectively 33 μs proton activities to the masses A=109 and A=113. An α decay of the 109I could be excluded up to α branching ratios of less 1.10-3. A proton decay of the 105Sb could be excluded by a measurement up to limiting cross sections below 1 μb in the energy range from 460 keV to 770 keV. By two independent arguments it was shown that the odd proton of the 105Sb is unbound but its proton branching ratio must be less than 2%. (orig.)