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Status of TRD Chamber and Readout Status of TRD Chamber and Readout Electronics IntegrationElectronics Integration
Ken Oyama and Christian Lippmann
for the TRD Collaboration
Sep. 26, 2005
TRD status meeting in Cheile Grădiştei, Romania
2005/Sep./25 2
ContentsContents
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.
2005/Sep./25 3
Situation TodaySituation 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
test beam stacktest beam stack
2005/Sep./25 4
Load Test of the Prototype Power Bus BarLoad 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).
ResultVoltage 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.
2005/Sep./25 5
(1) Before bus bar installation (2) After bus bar installation
pos0 #261.40
pos1 #251.45
pos3 #271.40
pos2 #281.44
pos5 #231.22
pos4 #241.30
pos0 #261.27
pos1 #251.32
pos3 #271.20
pos2 #281.24
pos5 #231.18
pos4 #241.15
memo: excluded dead or disconnected MCM’s for all measurements.
average1.37
average1.23
( 10 % better )
(3) If we exchange pos 1 and 5 ROB’s
pos0 #261.32
pos1 #231.19
pos3 #271.17
pos2 #281.26
pos5 #251.35
pos4 #241.13
Noise MeasurementNoise Measurement
Noise looks associated to robtype and regulator type.
2005/Sep./25 6
T4#0025 with new regulator T4#0023 with old regulator
Noise MeasurementNoise Measurementn
ew r
eg
ula
tors
sitt
ing
he
re
2005/Sep./25 7
AC component on 5 V pumped lineon patchworks without capacitors
With two 470 uF capacitorson 5 V pumped line
5V charge pump output (AC cpl.)
PASA output
Noise from Charge PumpNoise from Charge Pump
40 mV
2005/Sep./25 8
Two 470 uF for pos5:
pos0 #261.26
pos1 #231.17
pos3 #271.18
pos2 #281.21
pos5 #251.27
pos4 #241.12
Noise Level with Capacitances on Pumped LinesNoise 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.
2005/Sep./25 9
HV Improving #
pos0 #261.16
pos1 #231.10
pos3 #27OFF
pos2 #28OFF
pos5 #251.06
pos4 #241.04
# direct connection of HV GNDto pos4 ROB GND and better handling of cables.
Improving H.V. ConnectionsImproving 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.
2005/Sep./25 10
pos0 #261.04
pos1 #231.03
pos3 #xxOFF
pos2 #28OFF
pos5 #251.05
pos4 #241.03
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 NowThe Best Situation Till Now
average: 1.038
2005/Sep./25 13
Although small excess is at 8 o’clock Sep.12,noise level is very stable in ±10 electrons.
Long Term Stability of Noise LevelLong Term Stability of Noise Level
2005/Sep./25 14
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. MarinTesting 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
2005/Sep./25 15
ADC-PASA noise measurements(2)ADC-PASA noise measurements(2)
David Muthers, Kaiserslautern
http://www-alice.gsi.de/trd/meetings/status/050425/venelin_20050425.ppt
2005/Sep./25 16
PAD Capacitance Measurement by D.EmschermannPAD Capacitance Measurement by D.Emschermann
L1C1
2005/Sep./25 17
without padconnections
(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 L1C0S.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 DependencePad Capacitance Dependence
2005/Sep./25 18
ConclusionsConclusions
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.
2005/Sep./25 20
ADC-PASA noise measurements(3)ADC-PASA noise measurements(3)
David Muthers, Kaiserslautern
2005/Sep./25 23
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 ADigital 1.8V 35 AAnalog 1.8V 38 AAnalog 3.3V 29 Acooling
2005/Sep./25 24
ADC-PASA noise measurements(1)ADC-PASA noise measurements(1)
David Muthers, Kaiserslautern
2005/Sep./25 25
Noise Measurements 2Noise Measurements 2
strong effect of badly routed pre-trigger line.
But most of them have no problem.
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