Search

We discuss construction details of large drift chambers for the NA48 experiment at CERN. Preliminary measurements on their performance are also presented.

Experiment UA8 at the Sp p S-collider studied the production of hadronic jets in p p interactions which also contained final state protons or antiprotons with more than 90% of the full beam momentum of 315 GeV. Four Roman pot spectrometers were installed in interaction region LSS4 and interfaced to the data acquisition system of the UA2 calorimeter experiment, such that UA8 data could be logged on UA2 raw data tapes. In order to minimally perturb normal UA2 data acquisition and allow concurrent operation for the life of the experiment, an efficient high speed data-driven trigger processor was employed. The processor calculated the momentum of a track in a Roman pot spectrometer with 1.4% accuracy in 450 ns, thereby allowing a trigger decision to be made within 1.3 μs. We describe the integration of this processor into the high bandwidth readout of the UA8 wire chamber TDC system, and the on-line software package which monitored the hardware operation. The suppression of backgrounds from beam halo and multiple interactions in a bunch crossing is also discussed.

A fast trigger, based on principles of data-driven processing, has been designed and tested for CERN SPS-Collider experiment UA8. The electronics calculates the momentum vector of a track traversing the UA8 Roman pot spectrometer in 500 ns. When imbedded in the chamber TDC readout system, the total time between signal arrival in the counting room and result is 1.2 μs. The calculations are performed by successive table look-ups and arithmetic operations executed by several examples of a single type of module configured in a data-driven architecture. The operation of the system is monitored with a package of control and diagnostic software. The trigger processor has been successfully tested at the SPS-Collider.