A self-triggering silicon-tracking telescope for spectator proton detection

With the ANKE spectrometer at the COoler SYnchrotron COSY Juelich the mesonic structure of the nucleon will be studied in polarized proton-proton and proton-deuteron collisions. The identification and tracking of low energy protons permits using deuterium as an effective neutron target. For this purpose, modular self-triggering tracking telescopes built up by double-sided silicon strip detectors inside the accelerator ultra-high vacuum have been developed. Their basic features are ΔE/E proton identification from 2.5 $40 MeV and particle tracking over a wide dynamic range, either 2.5 MeV spectator protons or minimum ionizing particles. By the use of self-triggering read-out chips, the telescopes identify a particle passage within 100 ns and therefore allow the possibility of a fast hit pattern recognition. In combination with a read-out pitch of ∼200 μm, they provide a high rate capability. The recent development of very thick (≥5 mm) double-sided microstructured Si(Li) and very thin (≤65 μm) double-sided Si-detectors provides the use of the telescopes over a wide range of particle energies.