2008, July Nantes 1 APD Tests : Status and Protocol Giuseppe S. Pappalardo INFN Catania

2008, July Nantes 2 APD testing station in Catania Protocol Test results Conclusions and Perspectives Outline

2008, July Nantes 3 Testing set-up / 1

2008, July Nantes 4 Testing set-up / 2

2008, July Nantes 5 Testing set-up / 3

2008, July Nantes 6 APD dependence on the bias voltage M(V) = H(V) / H(plateau) Parameterization with an exponential plus a constant: M(V) = p 0 + p 1 exp(p 2 V) 16 APDs under test simultaneously

2008, July Nantes 7 Definition of the plateau /1 1) H(plateau) = p0+p1 (from fit) -> not stable 2) H(plateau) = H(50)

2008, July Nantes 8 Definition of the plateau /2 Fit done only in the V30 region

2008, July Nantes 9 Time schedule for the tests ~10 min to assembly APDs on the plate ~20 min for the temperature stabilization ~40 min for the measurement of the gain curve + analysis About 1 h 10 min to test 15 APDs (1 APD left as a reference) About 6.5 week to test 1300 APDs (from Sept 1 to Oct 15)

2008, July Nantes 10 APD Gain dependence on temperature /1

2008, July Nantes 11 APD Gain dependence on temperature/2 APD 1-8

2008, July Nantes 12 APD Gain dependence on temperature/3 APD 9-16

2008, July Nantes 13 APD Gain dependence on temperature/4 - Small fluctuations from APD to APD - Realistic measurement of the temperature (thermal equilibrium and thermocouple position)

2008, July Nantes 14 Temperature coefficient 1/M dM/dT = -1.7 % M = 30) Example:  T =  1° C M = 30  0.5

15 Since now we have tested about 170 APDs The average value of V30 is 362 Volts with an RMS of 13 Volts 10% of APDs have a V30>380 Volts 3.5% of APDs have a V30>390 Volts V30 statistics:

2008, July Nantes 16 Conclusions and Perspectives Present Status: A working testing station has been set up Procedure tested In the future: Starting the testing activity for APD mass production in September Realization of the system for gluing APD and light guide

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