S117 Meeting - 28.2.1995 - 10:30

• Attendance:

  S. Fritz, C. Groß, X. Hongfei, U. Kleinevoß, Walter F.J. Müller (since 11:00), B. Ocker, T. Odeh, C. Schwarz, V. Serfling, W. Trautmann.

• Topics:

  1. Chamber Rotation:

  Th rotation of the scattering chamber is planned for the beginning of next week. There was a remark by Giovanni via phone one should compare the telescope spectra for forward and backward angles. at 1 GeV. Acoording to GJ Kundes Diploma thesis one can expect a 2MeV increase in T between 50 and 200 MeV in the system

  He-4 -> p + t

  which means that the Helium is ok for the reversed setup concerning the thresholds.

  2. Analysis:

  a. Hodoscope trigger:

  The spectra for 1 GeV Catania deltaE-E with a trigger: "2 particles in the CsJ" were compared with the 600 MeV GSI deltaE-E and a trigger: "2 high signals in the Si". For the CsJ trigger no lines could be resoveld while for the 600 MeV one could distinguish between alphas and protons.

  b. ZDO spectra for 100 MeV:

  Raw time spectra for all detectors: The width of the spectra was in the order of 200 channels (5ns). The position of the peak varied in the order of 2000 channels form detector to detector, which can only be understood by different logic delays. This has to be tested.

  Raw hit pattern spectra for ZDO: Three detectors where the pedestal subtraction was actually too low were firing for every event (26, 28, 32). The three detectors with a very high gain had a 20% higher count rate.

  DeltaE-E for a good, an average and a bad detector: For the good detector even p,d,t could be resolved. For the bad detector essentially no line could be seen. The main problem seems to be the amplification factor of the photomultiplier. This was backed by cosmics spectra. The"bad detector" could not resolve the cosmic signal form the noise background, while the "good" and the "average" could do. A possible sollution of this porblem is to either exchange the photomultiplier of the detectors with very low output or the bases.

• Next meeting: 7.3.1995