1. Cristina Lo Bianco - LLR Cosmics test for the W-Si prototype (CALICE) Why the test in cosmics? The cosmics test-bench DAQ for the cosmics test-bench All active detector “slabs” will be individually tested in cosmics before being slided into the Ecal Prototype

2. Cristina Lo Bianco - LLR Why the test in cosmics? Two main goals: To verify the assembling of the slab To intercalibrate the Si wafers in order to take into account the difference in thickness from wafer to wafer In addition, the cosmics test-bench will be used by U.K people for testing the DAQ for the prototype.

3. Cristina Lo Bianco - LLR It will be possible to : estimate the electronics gain and noise and perform a calibration for each pad obtain a rough extimation of cross correlation between pads verify the electric contact between the Si wafer and the PCB (conductive glue) discover and mend everything that could possibly go wrong Why the test in cosmics? Check of the assembling

4. Cristina Lo Bianco - LLR The thickness of the Si wafers is given by the producer with a 3% tolerance, which propagates in a 3% uncertainity on the energy resolution Testing in cosmics for approximately 450 hours (18.6 “full days”) it will be possible to achieve, for all the wafers, a intercalibration at 0.3 % precision Why the test in cosmics? Intercalibration of the Si Wafers

5. Cristina Lo Bianco - LLR The cosmics test-bench Typical value for muons flux at sea level (PDG): 80 m -2 s -1 sr -1 Estimated flux per wafer: 0.056 muons s -1

6. Cristina Lo Bianco - LLR The cosmics test-bench Typical value for muons flux at sea level (PDG): 80 m -2 s -1 sr -1 Extimated flux per wafer: 0.056 muons s -1 8,3 mm Aluminum foil : ~0.1 mm PCB : 2.4 mm Wafer : 0.525 mm Carbon fiber : 0.15 mm W plate : 1.4 mm

7. Cristina Lo Bianco - LLR DAQ for the cosmics test bench -Veto time: ~ 100  s -  period for pad: ~ 640 s

8. Cristina Lo Bianco - LLR Present status of the test-bench Everything is in the lab and ready for assembling: scintillator planes exist electronics exists we have one PCB (type1) with two chips from LAL for preliminary tests What is left to do: connecting all the electronics (one month) developing the software for the data acquisition and analysis

9. Cristina Lo Bianco - LLR Conclusion The cosmics test-bench will be ready for first measurements at the end of June (a student will work on the assembling in April-May-June) July-August will be devoted to preliminary tests with the type1 PCB Measurements of final PCBs will start in January and last approximately 2 months (for a 0.3% precision)