From Igor.Konorov@cern.ch Thu Sep 4 13:56:28 2003 Date: Tue, 31 Aug 1999 11:36:53 +0200 (METDST) From: Igor Konorov To: COMPASS calorimeter people , igor.savin@cern.ch, inaba@kekvax.kek.jp, murraym@vsnhd1.cern.ch, oleg.gavrichtchouk@cern.ch, singovski@cern.ch, sougoniaev@cern.ch, stroot@cern.ch, takamatsu@cern.ch, tsuru@cern.ch, vladimir.poliakov@cern.ch, vsteiner@fnal.gov Dear colleagues , on August 9-th we discussed test results of two ADC prototype modules which were developed specially for COMPASS. Both modules were tested in the lab and in X5 test beam. The main parameters of the ADC modules are submitted in the next table: FI ADC ADC with KEK's QAC Dynamic 12bits 12 bits range Linearity >10bits >10bits measurement were limited by linearity of pulse generator Power 70 Watts 20 Watts consumption Channel price about $40 about $40 without crate Dead Gate+30ns Gate+350ns !!!!!!!!! time Channels 64 64 in one module Components available a new cycle availability of QAC production 4-5 month A main difference between two designs is a dead time. If the gate signal is 70ns long the dead time of FI ADC is about 100-110 ns verses 430-450ns of ADC with KEK's QAC. Taking in to account this difference in the performance it has been decided to use FI ADC for all COMPASS calorimeters. A final design of FI ADC module is in progress now. Components will be ordered in the middle of September. A test of a first module is expected in November 1999. A mass production can be started in January. Best regards. Igor.