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

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.

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

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

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

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

8,3

mm

Aluminum foil : ~0.1 mmAluminum foil : ~0.1 mm

PCB : 2.4 mmPCB : 2.4 mmWafer : 0.525 mmWafer : 0.525 mm

Carbon fiber : 0.15 mmCarbon fiber : 0.15 mmW plate : 1.4 mmW plate : 1.4 mm

Cristina Lo Bianco - LLR

DAQ for the cosmics test bench-Veto time: ~ 100 s period for pad: ~ 640 s

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

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)