26 MAY 2004Jacques Lefrancois1 PRR for LED SYSTEMS 3 notes distributed + 3 presentations (Anatoli, Ivan, Evgueni) Large amount of work ; many prototypes exist Very positive trend toward common design and common components. One common problem=> a good candidate for power switch for LED driver was DS0026 which is obsolete => components still exist in retailers. A new chip (compatible pin for pin is EL7212) It is urgent to test in radiation the DS0026 and EL7212 for about 20 Krads and 100Krads at the PS (in coming weeks?) THE PREFERED CHOICE FOR ALL 3 DETECTORS IS THE EL7212 (IF BOTH CHIPS PASS RADIATION TEST) Ecal presented a summary planning=> PS/SPD +HCAL should do such a summary

26 MAY 2004Jacques Lefrancois2 HCAL SYSTEM Modification on driver toward a common ECAL/HCAL system (Anatoli and Yuri) => test done on blue LED (PS/SPD type) Since there are two types of blue Wustlich LED => test should be done on 2 class (fast and slow) of LED selected at INR As for all 3 detectors choice between DS0026 and EL7212 pendant With this reservation PRR OK

26 MAY 2004Jacques Lefrancois3 ECAL SYSTEM Layout and grouping of fibers and pin diodes refined Preproduction prototype of LED driver exist Light distribution box defined Decision on fiber bending not final; test continue on heat shaping of fiber for small radius of curvature (in groups) => a test with mockup of a difficult region for fiber layout recommended Once choice of driver switch done, a test of pulseshape with red LED should be done => adjustment of pulseshape possible Position of upper LED box defined => position of CWLED control cards should be defined (some box up?) Planning tight: PRR OK pending on points above to be checked in December?

26 MAY 2004Jacques Lefrancois4 PS/SPD system Prototypes of Splitter and driver cards exist which satisfy request Because of fraction of slow LED from Wustlich more LED should be ordered => How to check that the next batch is not all slow LED ? The layout seems difficult in the inner region => many readout clear fibers and 9 driver box per module. It is recommended to do a drawing of overall layout of one inner module (Clermont INR next month?) The position and even design of the control box for LED adjustable voltage is not defined enough => it should be as the ECAL/HCAL box but more LED control is needed and less CW control than for ECAL/HCAL Study needed. PRR OK excepts for points pending.