Adamczewski-Musch, J.

Balog, T.

Chatterji, S.

Eschke, J.

Heuser, J. M.

Kleipa, V.

Kolb, B.

Kotynia, A.

Linev, S.

Lymanets, A.

Malygina, H.

Müller, W. F. J.

Niebur, W.

Schmidt, C. J.

Simons, C.

Sorokin, I.

Vassiliev, I.

Zumbruch, P.

GSI Repository

In-beam test of a prototype CBM Silicon Tracking System at COSY∗J. M. Heuser1, W. Niebur1, J. Eschke1, S. Chatterji1, C. J. Schmidt1, W. F. J. Mu¨ller1, I. Vassiliev1,V. Kleipa1, C. Simons1, T. Balog1,2, S. Linev1, J. Adamczewski-Musch1, B. Kolb1, P. Zumbruch1,A. Lymanets3,4, I. Sorokin5,4, A. Kotynia5, and H. Malygina51GSI, Darmstadt, Germany; 2Comenius University, Bratislava, Slovakia; 3Eberhard Karls University, Tu¨bingen,Germany; 4Kiev Institute for Nuclear Research, Kiev, Ukraine; 5Goethe University, Frankfurt, GermanyIn January 2012, a prototype setup of the Silicon Track-ing System (STS) for the CBM Experiment has been testedin a 2.4 GeV/c proton beam at the COSY synchrotron ofResearch Center Ju¨lich, Germany. The experiment aimedat a full-sytem test of prototype detector stations, data ac-quisition system, detector controls and online monitoring.Hit and cluster finding algorithms were applied to evaluatethe performance of neutron-irradiated prototype sensors. Asimple track reconstruction algorithm was applied to thedata acquired to determine the position resolution of thesystem.Experimemtal set-upThe experiment in the JESSICA cave is shown in Fig. 1.It comprised three silicon detector stations and two scin-tillating fiber hodoscopes for beam monitoring. A furtherCBM prototype detector for the muon detection systemwas installed downstream of the silicon stations. All detec-tors were read out with self-triggering front-end electron-ics based on the n-XYTER1.0 ASIC that delivered time-stamped digitized analog data to the acquisition system.The two outer silicon stations, operated already in the 2010beam test [1], included CBM02 prototype sensors and wereused as reference detectors. In the middle station, thatcould be rotated around the vertical axis to allow for differ-ent beam incidence angles, CBM04 prototype sensors wereunder test irradiated with neutrons up to the maximum flu-ence 1014 neq/cm2 expected in the CBM experiment. Thesensors have been described in [2].Figure 1: Beam test set-up of the prototype STS.∗Work supported by EU-FP7 HadronPhysics3.ResultsThe amplitude distributions of particle hits in the sensorsdemonstrated clear separation of the signal from the noise.An example of a strip hit pattern is shown in Fig. 2 (a).With increasing beam incidence angle, the charge spreadover clusters of adjacent strips grows as expected, which isshown in Fig. 2 (b). After geometrical alignment of the sys-tem a simple track algorithm was applied to selected eventswith single particle hits, as depicted in Fig. 3. The spatialresolution obtained in both transverse coordinates was ofthe order of 35 µm for the reference stations, about a factortwo worse that expected from the 58 µm strip pitch alone.The resolution of the irradiated sensors was slightly worse.It has to be further investigated how the increased currentswith irradiated sensors and thus imposed higher thresholds,and other factors, impact on those results.(a) (b)Figure 2: (a) Example of a single strip fired by a passingproton in a test sensor with 256 strips. (b) Cluster chargeas a function of the beam incidence angle.Figure 3: A reconstructed track shown in two projections.References[1] GSI Scientific Report 2010 26[2] GSI Scientific Reports 2009 10 and 2011 34PHN-NQM-EXP-27 GSI SCIENTIFIC REPORT 201256

In-beam test of a prototype CBM Silicon Tracking System at COSY

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In-beam test of a prototype CBM Silicon Tracking System at COSY

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