1. Status of TRD Chamber and Readout Electronics Integration Ken Oyama and Christian Lippmann for the TRD Collaboration Sep. 26, 2005 TRD status meeting in Cheile Grădiştei, Romania

2. 2005/Sep./252 Contents Investigation for reducing noise. Remove external noise by good groundings and good H.V. connections. Testing of new type regulators with charge pump. Using pre-final power bus bar and its load test. Using prototype water cooling pipes and check noise level with it.

3. 2005/Sep./253 Situation Today What is different since before? 1. Power bus bar is there. 2. Cooling pipes are there. 3. Better HV connections. Recently, TRD test beam stack is mainly operated by M.Gutfleisch with the cosmic trigger, stably. Study for integration and grounding are mainly done for the stand alone chamber (S.A.C.) outside the stack. DCS (for CLK, Trig, SCSN) independently powered single MCM instead of T3 ROBs L1C0 stand alone chamber (S.A.C.) fully covered by the 6 T4 ROBs

4. 2005/Sep./254 Load Test of the Prototype Power Bus Bar A prototype power bus bar with 4 pairs of copper plates ( 0.7 mm x 50 mm each) was tested. 40 A current for each pair is given without cooling (total 160 A). Result Voltage drop in 60 cm bar at 40 A load current = 16 ± 1 mV  27 mV/m  0.67 mΩ/m. Expected resistance is 0.5 mΩ/m for pure copper at room temperature while our measurement is 34 % larger. Maximum voltage drop in supermodule will be ~200 mV. The bar had no significant heat (~ human skin) except for around the short cut point.

5. 2005/Sep./255 (1) Before bus bar installation(2) After bus bar installation pos0 #26 1.40 pos1 #25 1.45 pos3 #27 1.40 pos2 #28 1.44 pos5 #23 1.22 pos4 #24 1.30 pos0 #26 1.27 pos1 #25 1.32 pos3 #27 1.20 pos2 #28 1.24 pos5 #23 1.18 pos4 #24 1.15 memo: excluded dead or disconnected MCM’s for all measurements. average 1.37 average 1.23 ( 10 % better ) (3) If we exchange pos 1 and 5 ROB’s pos0 #26 1.32 pos1 #23 1.19 pos3 #27 1.17 pos2 #28 1.26 pos5 #25 1.35 pos4 #24 1.13 Noise Measurement Noise looks associated to rob type and regulator type.

6. 2005/Sep./256 T4#0025 with new regulatorT4#0023 with old regulator Noise Measurement new regulators sitting here

7. 2005/Sep./257 AC component on 5 V pumped line on patchworks without capacitors With two 470 uF capacitors on 5 V pumped line 5V charge pump output (AC cpl.) PASA output Noise from Charge Pump 40 mV

8. 2005/Sep./258 Two 470 uF for pos5: pos0 #26 1.26 pos1 #23 1.17 pos3 #27 1.18 pos2 #28 1.21 pos5 #25 1.27 pos4 #24 1.12 Noise Level with Capacitances on Pumped Lines Capacitors help but not yet perfect. Turning off of pos3 and pos2 did not help. Extra shielding and battery driving of charge pump did not help. Increasing connections among ROB’s help a bit but not yet perfect. Connecting HV GND of filter box to carbon surface did not help.

9. 2005/Sep./259 HV Improving # pos0 #26 1.16 pos1 #23 1.10 pos3 #27 OFF pos2 #28 OFF pos5 #25 1.06 pos4 #24 1.04 # direct connection of HV GND to pos4 ROB GND and better handling of cables. Improving H.V. Connections 1.It was found that noise is significantly reduced (> 60 e) if we connect H.V.GND of H.V. filter box to PASA GND on nearest ROB (number above). 2.C.Lippmann found that pos0 noise significantly increased at some point (> to 1.3 LSB). This gave us a hint that handling of H.V. connection from filter box to ROB is really important.

10. 2005/Sep./2510 pos0 #26 1.04 pos1 #23 1.03 pos3 #xx OFF pos2 #28 OFF pos5 #25 1.05 pos4 #24 1.03 Last steps were: All HV cables from filter box to anode segments were cut to appropriate length (25 cm for row0 and 1). And well gathered and taped so that loop area is minimized. Red (final) HV cables from HV distribution box to filter box with length similar to that in the super-module, SHV connectors of filter box replaced by soldering. This gives little bit less noise but not significant. With these connections, noise level does not increase significantly even if you switch back to using charge pump (less than 20 e contribution). No additional shielding by aluminum foils around chamber is necessary. The Best Situation Till Now average: 1.038

11. 2005/Sep./2511 Pos0 Results

12. 2005/Sep./2512 Pos1 Results

13. 2005/Sep./2513 Although small excess is at 8 o’clock Sep.12, noise level is very stable in ±10 electrons. Long Term Stability of Noise Level

14. 2005/Sep./2514 Result Average RMS for MCMs under the pipes without pipe : 1.08 LSB (1.08 for Pos1) no grounding of pipe : 1.09 LSB (1.08 for Pos1) grounding to L-profile : 1.10 LSB (1.09 for Pos1) grounding to PASA GND : 1.08 LSB (1.08 for Pos1) Conclusion No significant effect due to pipes but grounding to PASA GND looks the best. Probably It is safer to have this option. Testing with Water Cooling Pipe Made by A. Marin Cooling water pipes & plates on only MCM0-7 on Position 0 ROB Grounding by copper strip to ROB PASA GND

15. 2005/Sep./2515 ADC-PASA noise measurements(2) David Muthers, Kaiserslautern http://www-alice.gsi.de/trd/meetings/status/050425/venelin_20050425.ppt

16. 2005/Sep./2516 PAD Capacitance Measurement by D.Emschermann L1C1

17. 2005/Sep./2517 without pad connections (0.64 in avg.) Pad C are from D.Emschermann’s measurements on L1C1 chamber, and scaled for L1C0 chamber using difference of PAD sizes (80 / 75 and 90 / 75 for row 0 and 1, respectively). In addition, 3.5 pF due to connectors, balls, and traces on ROB and MCM is added. Measurement from D.Muthers and I.Rusanov were multiplied by 1000/1200 because ADC range setup is different between their measurement and our S.A.C. measurement on L1C0 S.A.C (1.04 in avg.) Note: Fit result for ROB on Chamber thru ADC is: 0.020 * C + 0.577 LSB’s. Line width show 2 sigma deviation. Chi2 / NDF= 2.2 / 473. Pad Capacitance Dependence

18. 2005/Sep./2518 Conclusions Noise level is significantly improved from ~1.37 LSB (1560 e) to ~1.04 LSB (1250 e). Finalizing grounding method and H.V. connections were almost done but still maybe we can improve (900 e nolse contribution might be still there). We can investigate whether the noise level stays like now in LSB if we vary gain setup of ADC, and check what is the dominant source is 900 e noise. Testing of power bus bar was done. Basic test of water pipe was done and there was no significant effect in noise level.

19. 2005/Sep./2519 Backup Slides

20. 2005/Sep./2520 ADC-PASA noise measurements(3) David Muthers, Kaiserslautern

21. 2005/Sep./2521 Pos4 Results

22. 2005/Sep./2522 Pos5 Results

23. 2005/Sep./2523 Current per bus bar: Digital 3.3V 8 A + ~5 A TRAP + OASE Digital 1.8V 35 A ADC Analog 1.8V 38 A ADC Analog 3.3V 29 A PASA Digital and Analog should not be mixed: Digital 48 A Analog 67 A * Analog should be closer to the cooling water pipe * PASA can not be touched to digital so … Digital 3.3V ~13 A Digital 1.8V 35 A Analog 1.8V 38 A Analog 3.3V 29 A cooling

24. 2005/Sep./2524 ADC-PASA noise measurements(1) David Muthers, Kaiserslautern

25. 2005/Sep./2525 Noise Measurements 2 strong effect of badly routed pre- trigger line. But most of them have no problem.

26. 2005/Sep./2526 No Correlation between with and w.o. PADs

27. 2005/Sep./2527