S117 meeting, 25.7.95

ZDO

• If one plots the neighbour detector of an detector with unidentified line, coincidences to the ULI look like punchtrough particles: a certain amount of energy is missing. The particle penetrates the DE detector and is scattered in the neighbour detector (ULI line: no DE).

• Wolgang suggests a check: detector without neigbours shouldn't show any ULI's.

Punchthroughs

• A new chi2 (robust) methode was applied to the search of the punchthrough branch: no success.
• Uli wants to have a 2-dim fit: the angles of p and alpha-punchtroughs are given by the energy loss in the silicon.
• Michael shows that the E projections give only little information about the punchthrough-location.
• Burkhard shows offsets of the hodoscopes: he compares the offsets determined with alpha-peak and pulser slope (~25#,large spread) and the offsets determined with alpha-peak and proton-PT (~40#, small spread). Since the calibration is meanwhile on the 20 keV level, one should take into account quenching effects of the silicons. Low voltage silicons show larger quenching effects.
• Burkhard shows also a E-E plot for alphas from neighbouring detectors showing a line at E1=E2 (Be8--> a+a (0MeV). Carsten produced a preliminary a-a correlation showing this feature as a peak at the right relative momentum (20 MeV/c). The correlation is still to low and has to be corrected for different possible error sources.

Italians