1. 4/25/2006 Puneeth Kalavase, UC, Santa Barbara On behalf of US Tracker Outer Barrel group Construction and Testing of CMS “Rods”

2. 4/25/2006 CMS Tracker 5.4 m Inner Barrel & Disks (TIB & TID) Pixels Outer Barrel (TOB) volume 24.4 m 3 running temperature – 10 0 C 2,4 m End Caps (TEC)

3. 4/25/2006 Rods 101 Rods – Basic self-contained element of the TOB.

4. 4/25/2006 Rods 101 Carbon Fiber rod frames are built at Helsinki and shipped to CERN where communications and cooling infrastructure are incorporated. Then sent to US (FNAL and UCSB) where they are populated with modules and tested. Rods come in 3 flavors –SS4 (Single Sided 4) - 6 modules each with 4 readout chips (512 channels). –SS6 (Single Sided 6) - 6 modules with 6 readout chips (768 channels). –DS4 (Double Sided 4) - 12 modules with 4 readout chips, 6 of which are small angle stereo for better resolution in z direction.

5. 4/25/2006 Tracker Outer Barrel (TOB)

6. 4/25/2006 RODS Communications Bus AOH (Analog Optohybrid)

7. 4/25/2006 Rod Assembly Rods are populated with sensors by engineers at both sites. Rate of rod assembly is 20-25 rods/week at each site.

8. 4/25/2006 Rod Testing Each rod put through preliminary 1 hour test in SRT (Single Rod Test stand). Basic functionality of Rods is tested. – Perform Pedestal run in all 4 operating modes of readout chip and Charge Injection test in 2 of the 4 operational modes Typical PedestalsTypical Noise Profile

9. 4/25/2006 Rod Testing Till now, most problems with the rods (new bad channels, communications failures, etc) have been found in SRT during our preliminary tests. After passing preliminary test, rods are tested in MRT (Multi Rod Test). –MRT has capability to test up to 8 rods at one time. –Goal is to push rods so that any weakness is discovered and fixed before integration in detector. Find possible pinholes, ie, weak coupling capacitors. –MRT is a 2 day “burn-in”. We stress rods rods by cycling the temperature of the coolant from 20C to -23C. Run tests in both warm and cold.

10. 4/25/2006 Rod Testing – Multi Rod Stand Lots of electrical, optical and cooling connections!

11. 4/25/2006 Bad Channel Flagging Normalized Noise distribution has nice, tight gaussian shape. Outliers are clearly visible and can be easily cut on.

12. 4/25/2006 Bad Channel Flagging Plot of normalized Pulseheights – response of channel to charge injection Open Channels Noisy Channels Shorts Pinholes (short in thin SiO2 layer, between AL strip and n-type bulk) would show up here. Important to find pinholes because they draw high current. Bad modules are removed from rods and thoroughly retested!

13. 4/25/2006 Leakage Current Monitoring Leakage Current is very important to catch pinholes. Typical modules will have leakage currents from 0.5-10 uA. If pinhole present, current will be much higher. uA

14. 4/25/2006 Rod Production Status On track to finish rod Production by mid summer at the latest!

15. 4/25/2006 Summary Module production is ramping down as we are almost done and the final step is to test and ship rods. Goal of testing is to stress rods and uncover any potential problems so that there are no surprises in detector. All problems encountered so far have been fixed. Production is going smoothly and rates are keeping pace with projected completion dates! Rods are being shipped to CERN for installation into TOB and final testing before integration with detector.