1. 1/8/04Lance Simms Thermal Testing of TOB/TEC Hybrids at UCSB

2. 1/8/04Lance Simms The CMS detector will run at –20 C in order to lessen radiation damage to the silicon Why Thermal Test?

3. 1/8/04Lance Simms Why Thermal Test Hybrids? Some Hybrids fail at –20 C –APVs do not output –Hybrid fails to initialize –Noise increases in cold (peltier current?) APV: Analog Pipeline Voltage Mode Chip

4. 1/8/04Lance Simms The 4 Hybrid Cold Box Cold box design and photo courtesy of: Bruno Wittmer and Giacomo Squazzoni @ CERN How to thermally test hybrids? 4 at a time.

5. 1/8/04Lance Simms The Set-up at CERN Picture courtesy of CERN

6. 1/8/04Lance Simms The Set-up at CERN

7. 1/8/04Lance Simms A question at Tracker week

8. 1/8/04Lance Simms Building our own Construction Construction & Repair Repair

9. 1/8/04Lance Simms Slow Control First order of business: hooking things up 5 temperature sensors 1 humidity sensor 1 Water Flow Sensor 1 Air Flow Sensor

10. 1/8/04Lance Simms Interfacing to a PC: ACDC

11. 1/8/04Lance Simms Cooling Down Cooling Mechanism: Peltier Unit Supercool Peltier: -Voltage = 28 V - Current = 13 A - Power = 350 W

12. 1/8/04Lance Simms Cooling Down How long should/does it take to get to –20? Cold chamber Peltier + Plate Chiller Air Air Flow (0.05 L/min) Water Flow (14 L/min)

13. 1/8/04Lance Simms Simplifying things S= surface area of enclosure (m ) k=thermal conductivity of walls (W/m C) h=convection factor (W/m C) x=thickness of walls (m)

14. 1/8/04Lance Simms Simplifying things Assumptions: 1)Most of the heat transferred to the system goes into cooling the aluminum peltier plate (specific heat of aluminum is much greater than that of air) m= 2.0 kg c= 910 J/kg C

15. 1/8/04Lance Simms Simplifying things Assumptions 2) The convection factor can be calculated by waiting until the system comes to equilibrium Temp at equilibrium

16. 1/8/04Lance Simms Simplifying things Waiting… (I was too impatient to wait for t ) h= 7.55 (W/m C)

17. 1/8/04Lance Simms Calculating time to -20 First order linear differential equation: Solution: (T(t=0)=295K)

18. 1/8/04Lance Simms Not quite… Calculation says that plate should reach –20 in ~14 minutes. Actual time: ~21 minutes Possible problems: Unaccounted heat influx through leaks or grounding strips connecting plate to outside assumptions made are flawed Missing term in differential equation

19. 1/8/04Lance Simms -20 Reached: On to Testing Set-up in Clean Room Chiller Cold Box PC for Monitoring + Controlling Electronics Gas/Water Flow Control

20. 1/8/04Lance Simms Testing Software: ARCS APV Readout Control Software Communicates With ACDC via TCP/UDP

21. 1/8/04Lance Simms What are we testing for? Shorted channels: On each clock, charge injected into every 8 th channel. Shorted channels share, ADC amplitude is diminished. 128 Channels per APV -6 APV hybrids: 768 -4 APV hybrids: 512

22. 1/8/04Lance Simms What are we testing for? Open Channels: Inject charge through Capacitive coupling of pitch adapter to antenna carrying TTL Pulse Antenna Pitch Adapter

23. 1/8/04Lance Simms Easier said than done Slide courtesy of G.Squazzoni

24. 1/8/04Lance Simms We thought it was the pulser ARC Board LVDS NIM Logic NIM TTL

25. 1/8/04Lance Simms LVDS Signal? ARC Boards with functioning External Bus –Ser 29 –Ser 31 ARC Boards with non-functioning External Bus –Ser 56 –Ser 57 –Ser 59 LVDS Signal Noise

26. 1/8/04Lance Simms ARC Controller Problem Bad Batch of ARC BOARDS: LVDS Driver and LVDS Receiver U32 and U33 were switched during board assembly. Problem was never discovered. External Buss connector and associated IC’s on lower left of photo. U32

27. 1/8/04Lance Simms With Pulser Operational… Opens detectable in “Scope Mode” Intentionally Plucked Bonds Show up in Pedestal Profile

28. 1/8/04Lance Simms With Pulser Operational…. Opens are also detectable in Pedestal & Noise Test Plucked Bonds

29. 1/8/04Lance Simms Grounding Issues Same Problem CERN was having…. Huge spikes in noise at APV edges

30. 1/8/04Lance Simms Grounding Ferrite Ring around Coax G10/copper strips connect peltier plate to front end ground

31. 1/8/04Lance Simms Much Better Old Grounding New Grounding

32. 1/8/04Lance Simms Thermal Cycle Test “One Button” test Three Sets of Tests: Pedestal & Noise Pulser Short Detection

33. 1/8/04Lance Simms Automated Test Results Final Report After Thermal Cycle Test: Lists -Shorts -Opens -Noisy Channels

34. 1/8/04Lance Simms The testing goes on… So far, about 100 hybrids have been thermal cycled. At maximum capacity: ~28 per day And the cycling will continue…