Bochum 1998 – scientific programme
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HK: Hadronen und Kerne
HK 60: Instrumentation VI, Detector Systems
HK 60.9: Talk
Thursday, March 19, 1998, 16:30–16:45, A
First Measurements with the Germanium Wall — •K. Grewer — Institut f"ur Kernphysik, Universit"at Münster, Wilhelm-Klemm Str. 9, D-48149 Münster
The reaction p + d → 3He + η has been investigated with the GEM detector system. The GEM detector system consists of the “GErmanium wall” and the Magnetic spectrometer "Big Karl”. The germanium wall is a stack of four position sensitive, high purity germanium detectors with radial symmetry with respect to the beam axis. The detectors cover the same angular range but vary in thickness and size. The first detector of the stack is 1.2 mm thick and acts as a tracker for emission direction and energy loss measurements. It has 200 Archimedes’ spirals on both sides with opposite bending direction thus defining 40000 pixels with a pixel size below 0.1 mm2. The following detectors are 17 mm thick and have a structure of 32 wedges on one side. The energy resolution was measured to be Δ E / E < 4 × 10−3 at 1.334 MeV. In the centre of the germanium wall is a hole corresponding to the acceptance of the magnetic spectrometer Big Karl. The acceptance of the whole detector system is approximately 260 msr.
The response of the germanium wall and first results of p + d → 3He + η measurements at a beam momentum of 1673 MeV/c with a preliminary setup of three germanium detectors will be discussed.
Supported by BMBF (Nr. 06 MS 568 I TP4) and FZ Jülich.