Operation results of the dynamitron tandem at Bochum

Abstract The performance of the Dynamitron-Tandem accelerator at Bochum with respect to beam energy resolution, stability and reproducibility, and beam intensity is reported. The energy resolution has been determined by measuring with thin targets (i) the shape of the neutron threshold in 7 Li(p, n) at E p = 1.88 MeV and the width of a single isolated resonance in the reaction 28 Si(p, p 1 ) at E p = 5.197 MeV, (ii) the fine structure distribution of the lowest 1 2 + isobaric analogue resonance in the reaction 92 Mo(p, p 0 ) near E p = 5.3 MeV, and (iii) the mean level width of the fluctuating excitation function near the lowest 1 2 + isobaric analogue resonance in the reaction 88 Sr(p, p 0 ) near E p = 6 MeV. These measurements yield ΔE E p = 1.88 MeV and ΔE = (1.5±0.2) keV at E p 28 Si(p, p 1 ) at 5.2 MeV was better than 120 eV and the absolute beam energy is reproducible to better than 3 × 10 −4 . Energy analyzed maximum beam currents so far are 125 μA for protons at 8 MeV and 27 μA for 16 O(4 + ) at 20 MeV. Operational experience of the tandem and its associated parts (high voltage generator, injector, beam handling system) over a period of about nine months has demonstrated the high reliability of the whole system. A major advantage compared to most accelerators is the extremely easy way to operate the machine.