Numerical Comparative Study of BPM Designs for the HESR at FAIR

The Institute of Nuclear Physics 4(IKP-4) of the Research Center Jülich (FZJ) is in charge of building and commissioning the High Energy Storage Ring (HESR) within the international Facility for Antiproton and Ion Research (FAIR) at Darmstadt. Simulations and numerical calculations were performed to characterize the beam position pickup design that is currently envisaged for the HESR, i.e. a diagonally cut cylindrical pickup. The behavior of the electrical equivalent circuit has been investigated with emphasis on capacitive cross coupling. Based on our findings, performance increasing changes to the design were introduced. A prototype of the BPM pickup was constructed and tested on a dedicated test bench. Preliminary results are presented. Another proposed design was characterized and put into comparison, as higher signal levels and higher position sensitivity are expected. That is a symmetrical straight four-strip geometry. Additionally an extensive study was conducted to quantify the effect of manufacturing tolerances. Driven by curiosity an eight-strip pickup design was considered, which would allow for beam size measurements, utilizing the non-linearity