B. IlleWACH /11/20021 WELCOME to WACH I am happy to introduce this ‘Workshop Analysis Calorimetry H4’ dedicated to M0’ data analysis and the preparation of next year’s activities in H4. I am sure it is the first of a long series, with plenty of good data about performance and calibration of our ECAL detector.

B. IlleWACH /11/20022 THE M0’ SYSTEM - About one year ago, we decided to assemble and to test with beam particles a barrel test system from M2, built in Some of us were not fully convinced because of the unsatisfactory frontend chips (bad news in 2001) and the amount of effort necessary to achieve our goal. Because some components were available and more or less ready (bare M2, Rose10, opto-link, HVS prototype, monitoring system …) we decided to try. - M0’ is the 1st complete barrel test system of ECAL, built according to the same construction ‘procedures’ (i-e under CRISTAL supervision) as the real detector, with all important parameters of each component stored in the CRISTAL DB: - M0’ = 100 channels of bare M2 equipped with ‘old light to light’ electronics (noisy FPPA) + final-specs Monitoring Laser system + services (cooling, final specs-proto HVS, DCS, LVS, …) + DAQ with Rose10 modules. - M0’ in H4 = M0’ + calibration table + on-line monitoring of beam/laser operations + beam equipments (hodoscope, mwpc) + links with cristal DB + noise …

B. IlleWACH /11/20023 M0’ and 100 R/O channels THE M0’ SYSTEM

B. IlleWACH /11/20024 M0’: some dates and numbers - VFE proto cards manufactured : february- march - Assembly and tests (100 channels): June – mid July 2002 in B27 - About 15 to 20 people (almost all here) involved - Installation in H4: last week of July - One week needed to get operational. First electron data: 29th of July - Long test period: days of beam (July-August-September) - More than runs, about 500 Gbytes of data recorded - About 70 shifters, motivated community with a good spirit. Some shifters were new-comers in ECAL (from the Belgrade group, Milano group, Prague group, CalTech, Minnesota, Lisbon …), even a colleague on the retired list came to help us during the difficult mid-August period ! - This represents a big effort, involving a lot of people. Many thanks to all !

B. IlleWACH /11/20025 M0’: some hardware highlights - WACH4 will review in details the performance and the problems of all the aspects of the M0’ system, including the Xtals. - But I want to emphasize here the successful operation of the Spinner opto-link associated with the Rose10 modules: - Ready from the beginning, after a delicate adjustment and tuning links functioning at 800 Mbits/s throughout the whole period without interruption. We just forgot about its existence during more than three months - Special thanks to Robert and Magnus, not present here, who contributed so much to this success - I want also to mention the good behaviour of the apds, especially during the severe irradiation with pions. It gives us confidence for the future ! - The small dispersion between channels to the monitoring laser light, without any sophisticated corrections (good surprise, at least for me !)

B. IlleWACH /11/20026 M0’: some lessons We know already from the test beam analysis meetings that we’ve got some good results (in spite of noisy FPPAs) but principally a lot of useful information. From my point of view, the list is rather substantial (cf Workshop program): - temperature stability, thermal dynamics of the system - experience with monitoring laser system (stability, temp dependence, monitoring electronics vs Xtals R/O, operation & maintenance…) - FPPA functionality (Idark, Temp measurements,gain switching …) - training with pulse reconstruction methods - Noise correlations : serious problems and vfe susceptibility to external noise - R factors of almost 20 Xtals, recovery dynamics … - auto-scans for calibration … - necessity to improve data management (huge set of data !) and on-line feedback - correlations with cristal DB, HVS etc … Most of these items will be discussed during WACH4. In particular I think noise studies deserve more effort. Whatever the frontend (FPPA or MGPA), we will have to face correlations !

B. IlleWACH /11/20027 This First WACH4 - The fact that we need such a Workshop indicates, I believe, that ‘the pain was worth the gain’. I think we learned a lot with such a relatively small system and most of what will be presented at the Workshop will be valuable for the future. - This first WACH4 is not only dedicated to the analysis of M0’ data, but also to the preparation of more complicated ECAL systems in 2003: the barrel SM0 and the endcap E0’ system. This is a big step forwards and we’ve still a long way to go ! In this respect, the session which is devoted to our next year’s strategy is particularly important.