CARIOCA Werner Riegler CERN November 24 th 2003

CARIOCA Werner Riegler, CERN November 24 th, 2003, LHCb week Discussion of the final Prototype results Plans for CARIOCA / ASDQ decision Werner Riegler CERN, November 2003

CARIOCA TDR: ASDQ is our baseline solution CARIOCA is our preferred solution caveat: we cannot afford ASDQ the Werner Riegler CERN, November 2003

CARIOCA u CARIOCA is a responsibility of the CERN LHCb muon group. u Francis Anghinolfi and Pierre Jarron are our ‘advisors’ from the MIC group. Werner Riegler CERN, November 2003

CARIOCA Block Diagram Preamp Signal tail cancellation 2 x pole/zero, t 0=1. 5 ns, topology from ASDQ Preamp tail cancellation 1 x pole/zero, topology from ATLAS MDT Topology from ATLAS MDT LVDS, standard cell topology from ATLAS MDT prototype Werner Riegler CERN, November 2003

Manpower Walter continues in Cagliari Werner Riegler CERN, November 2003

Submissions Werner Riegler CERN, November 2003

CARIOCA u We had a very useful review in February n We got very useful suggestions in order to increase stability (coupling). n Francis Anghinolfi got involved in order to help us ironing out some of the problems in the preamp. Werner Riegler CERN, November 2003

CARIOCA 10 u We received CARIOCA 10 on September 15 th. u Test board designed by Davide (Cagliari) and produced at CERN. u 17 CARIOCA boards were equipped 34 chips. u Tests were started October 1 st. u All test results can be found on http: //home. cern. ch/riegler Werner Riegler CERN, November 2003

CARIOCA 10 • 8 channels • pos/neg switch • Test pulse even/odd • 8 individual thresholds • Can be switched to a single threshold • Analog output of channel 8 Werner Riegler CERN, November 2003

CARIOCA 10 3 x 4 mm chip 82 pins 25 pins on each side Werner Riegler CERN, November 2003

CARIOCA 10 u Traditionally one does extensive LAB tests before putting the chip on the chamber. u Because our last testbeam period in T 11 was October 22 nd to Nov 11 th , lab test are not yet finished … u There is no way we could have advanced further up to now … u CARIOCA 10 was tested on M 3 R 3 (4 boards), GEM (6 boards) and we fully equipped a CERN M 3 R 1 chamber. u We found a nice way for high rate tests in GIF without having beam – this is also ongoing. u Results are preliminary Werner Riegler CERN, November 2003

CARIOCA 10 test board We wanted the results quickly, we don’t have the final package ®We did an ‘optimum’ and ‘worst case’ package: Optimum Package (‘no package’): • Chip bulk is glued to the board gound with conductive Epoxi, • Wire bonds are very short Worst Case Package: • Chip bulk is insulated from the board gound • Wire bonds are very long Werner Riegler CERN, November 2003

Sensitivity (discriminator) On CARIOCA 10, sensitivity was doubled in order to decrease minumum detectable charge (4 f. C 2 f. C) for GEM application. Maximum threshold is 300 m. V (limited by discriminator). Sensitivity decreases by factor 2 from 0 to 220 p. F. Werner Riegler CERN, November 2003

Sensitivity variations Werner Riegler CERN, November 2003 Channel to channel variations are smaller than chip to chip variations

Sensitivity Variations, 0 p. F Pos: 16. 0 m. V/f. C, 0. 56 m. V/f. C r. m. s, i. e. 3. 54%. Pos: 14. 5 m. V/f. C, 0. 62 m. V/f. C r. m. s, i. e. 4. 31% ‘package’ causes a decrease of 9% Neg: 14. 7 m. V/f. C , 0. 56 m. V/f. C r. m. s. , i. e. 3. 8% Neg: 13. 1 m. V/f. C, 0. 56 m. V/f. C i. e. 4. 3% ‘package’ causes a decrease of 11%. Werner Riegler CERN, November 2003

Sensitivity Variations, 0 p. F Subtracting average per chip and scaling by Sqrt(8/7) Pos: 16. 0 m. V/f. C, 0. 34 m. V/f. C r. m. s, i. e. 2. 15%. Pos: 14. 5 m. V/f. C, 0. 34 m. V/f. C r. m. s, i. e. 2. 36% Neg: 14. 7 m. V/f. C , 0. 40 m. V/f. C r. m. s. , i. e. 2. 7% Neg: 13. 1 m. V/f. C, 0. 26 m. V/f. C i. e. 2. 0% Werner Riegler CERN, November 2003

Sensitivity Variations Sensitivity is 16(14. 7) m. V/f. C for the positive (negative) amplifier. Sensitivity variations are <5% r. m. s. The DIALOG DACs have 2. 44 m. V LSB I. e. 0. 16 f. C @ 0 p. F and 0. 32 f. C @ 220 p. F Werner Riegler CERN, November 2003

Extrapol. Minumum Detectable Charge 2. 4 f. C, 0. 37 f. C r. m. s. 2. 4 f. C, 0. 24 f. C r. m. s Minumum detectable charge is correlated with the sensitivity, I. e. the reason for this Limit is a minimum voltage pulse at the Discriminator input in order to make it fire. Werner Riegler CERN, November 2003

Offsets u Offsets were measured on 272 channels by recording the threshold value that inverts the discriminator output. u One DTV sets the threshold for all 8 channels. Werner Riegler CERN, November 2003

Offsets Channel to channel variations are smaller than chip to chip variations Werner Riegler CERN, November 2003

Offsets 795. 6 m. V, 9. 9 m. V r. m. s. The threshold DACs on the DIALOG chip have a range of 625 m. V to 1250 m. V in 8 bits i. e. bins of 2. 44 m. V. This is perfectly compatible with this kind of offset spread. Werner Riegler CERN, November 2003

Offsets Subtracting the average offset for each chip and multiplying by sqrt(8/7) gives an rms of 4. 54 m. V. This is the ‘true’ channel to channel variation. It corresponds to 0. 3 f. C at 0 p. F and 0. 6 f. C at 220 p. F Werner Riegler CERN, November 2003

The DTV applies the differential threshold voltage to the discriminator. Werner Riegler CERN, November 2003

DTV itself has an offset of about 7. 5 m. V r. m. s Werner Riegler CERN, November 2003

Werner Riegler CERN, November 2003

Offsets+Sensitivity u The channel to channel variation of the sensitivity is <5%. u The channel to channel offset variation is around 5 m. V r. m. s. u Together with the DTV the channel to channel offset variation is 10 m. V r. m. s. u Both variations become ‘irrelevant’ when we use individual thresholds. Werner Riegler CERN, November 2003

Noise Neg: 2240+42 e-/p. F At 0/100/200 p. F we can use Pos: 1880+45 e-/p. F threshold of 1. 5/5/10 f. C. Werner Riegler CERN, November 2003

Power Consumption Power consumption is 43. 3/46. 6 m. W/channel for the positive/negative amplifier. On on board (16 channels) the CARIOCA consumes 0. 75 W. +DIALOG +Voltage drop from regulator …. Werner Riegler CERN, November 2003

Chamber Test in T 11 u M 3 R 1 module 1 chamber (double cathode readout) u Uniformity of this chamber was measured with CARIOCA 9 for the CERN PRR. u Crosstalk for single/double cathode readout was evaluated for this chamber with CARIOCA 9. Werner Riegler CERN, November 2003

N 3 P 9 P 10 P 11 N 6 N 7 N 8 S 1 S 2, no package S 3 S 4, package 3, 14 2, 15 1, 16 8, 9 7, 10 6, 11 5, 12 4, 13 3, 14 2, 15 1, 16 8, 9 7, 10 6, 11 5, 12 Beam goes into the drawing P 14 P 16 8, 9 7, 10 6, 11 5, 12 4, 13 3, 14 2, 15 1, 16 2, 15 3, 14 4, 13 5, 12 6, 11 7, 10 8, 9 1, 16 2, 15 3, 14 4, 13 1, 16 5, 12 Gas N 5 4, 13 5, 12 P 12 N 4 6, 11 2, 15 6, 11 master test P 13 P 15 HV Werner Riegler CERN, November 2003

Chamber test in T 11 Werner Riegler CERN, November 2003

Chamber test T 11 Dialog -1 Werner Riegler CERN, November 2003

Chamber test T 11 Offsets are corrected by 194 individual thresholds. This will finally be done by DIALOG … Werner Riegler CERN, November 2003

Chamber test T 11 All outputs were connected to the LVDS-ECL converter with our ‘final’ shielded twisted pair cables. Werner Riegler CERN, November 2003

Chamber Test in T 11 u We used 45 m. V threshold ( 6 -7 f. C) on all 196 channels. u All channels had <50 Hz dark count rate. u Excellent stability ‘without’ dummy capacitor and without shielding ! Werner Riegler CERN, November 2003

Symmetric Termination Due to the large detector capacitance the frontend is extremely sensitive to ground noise (Cdet=100 p. F, 50 V fires the 5 f. C threshold). With symmetric termination the chip becomes ‘immune’ to this effect. Penalty: larger noise ! ‘Up to CARIOCA 8’ we needed this dummy capacitor since the discriminator firing was causing a large pulse on the chip ground. For CARIOCA 9/10, many measures were taken in order to reduce this coupling, especially disconnection of substrate contacts in transistors of the digital part. With the final prototype things work perfectly fine without the dummy capacitor, but we still have this option ! Werner Riegler CERN, November 2003

45 m. V threshold on all Pads - Cathode Pad numbers: Capacitance Threshold 112 108 98 88 7. 6, 7. 4 6. 9, 7. 0 6. 7, 6. 6 5. 9, 6. 2 f. C 7. 3, 6. 6 7. 3, 6. 2 6. 6, 6. 8 6. 5, 6. 5 f. C Noise 1. 3, 1. 2 1. 1, 1. 3 0. 6, 1. 1 f. C 1. 3, 1. 1, 1. 2 f. C HV Werner Riegler CERN, November 2003

45 m. V threshold on all pads: wire pad numbers Wire Pad Capacitances 26. 5 -28. 5 p. F Thresholds 6. 2, 7. 4 f. C Noise 0. 67, 0. 69 f. C HV Werner Riegler CERN, November 2003

Cathode Efficiency 95% 2. 42 k. V 99% 2. 54 k. V 95% 2. 45 k. V 99% 2. 56 k. V Werner Riegler CERN, November 2003

Wire Efficiency 95% 2. 4 k. V 99% 2. 5 k. V 95% 2. 43 k. V 99% 2. 55 k. V Werner Riegler CERN, November 2003

Detector Capacitance u The cathode pad capacitance in the entire muon system will not exceed 120 p. F, so with the M 3 R 1 chamber we have already tested the largest cathode capacitances ! u We will however have wire pad chambers with capacitance up to 220 p. F (R 4) while the M 3 R 1 chamber has only 30 p. F wire pad capacitances. u Since we don’t have a wire pad chamber we measured the efficiency by adding capacitors to the wire pad. Werner Riegler CERN, November 2003

On Chamber Wire pad Noise packaged and non packaged chip Werner Riegler CERN, November 2003

Wire Pad Efficiency for different Capacitances nonpackage side Werner Riegler CERN, November 2003

Efficiency u 2. 5 k. V is a good working point that gives >95% efficiency on the double gap (>99% on the quad gap). u 2. 65 k. V is a good working point that gives >99% efficiency on the double gap. Werner Riegler CERN, November 2003

Crosstalk: Probability of firing the Neighboring pad (infinite time window) Plot presented at the PRR: Measured with CARIOCA 9 on the M 1 R 3 Prototype on Pad Position P 9, 7/10. We decided to use doubel cathode readout since we can survive with 10% crosstalk. In M 2 M 3 R 1 R 2 the trigger granularity is given by the wire pads, not the cathode Pads. Crosstalk ‘only’ increases the rate. Werner Riegler CERN, November 2003

Crosstalk CARIOCA 9, single, thr 4. 7 f. C, position P 9, 7/10 CARIOCA 9, double, thr 6. 8 f. C, position. P 9, 7/10 CARIOCA 10, double, thr 7 f. C, position P 11, 7/10, no package (S 1 S 2) CARIOCA 10, double, thr 7 f. C, position P 11, 7/10, package (S 3 S 4) CARIOCA 10, double, thr 7 f. C, position P 13, 3/14, no package CARIOCA 10, double, thr 6. 7 f. C, position P 13, 3/14, package (S 3 S 4) ? ? ? ? Werner Riegler CERN, November 2003

Crosstalk The preamp input stage was actually changed for CARIOCA 10 in order to improve the signal tail at large capacitances (phase margin). The design value was 50 since from simulations we know that this is a good value (ASDQ++ used 25 ). Werner Riegler CERN, November 2003

Crosstalk Fraction u Injecting a delta signal in one pad finds a signal on a neighbour pad. u We call the ratio of the two pulse heights the crosstalk fraction. Werner Riegler CERN, November 2003

Crosstalk Fraction 1. 7% 1. 4% 1. 5% 1. 8% 1. 5% 1. 4% 1. 7% 1. 5% 1. 4% 2. 1% 1. 7% 1. 6% 2. 2% 1. 6% 1. 7% 2. 2% 1. 6% 2. 1% 1. 6% 1. 7% CARIOCA 9 CARIOCA 10 HV Werner Riegler CERN, November 2003

Crosstalk Fraction u The crosstalk fraction of the M 3 R 1 chamber using CARIOCA 10 is 1. 6 -2. 2%. u It is 10 -30% larger than for CARIOCA 9. u This is a small increase and the 2. 2% crosstalk fraction is well within our specifications. u Some time ago we found that we have >95% efficiency if our threshold is at <30% of the average signal and >99% efficiency of our threshold is <20% of the average signal (1. 5 mm pitch). u With a crosstalk fraction of 20% and 2. 2% crosstalk fraction there is no way to have such a large crosstalk ! Werner Riegler CERN, November 2003

Crosstalk Simulated Pulse Height Spectrum MEDIAN is at 50. Crosstalk is defined as the probability That a neighbor pad fires. This depends on Gas Gain and threshold. Crosstalk Fraction is defined as the fraction of Pulse height on a neighbor pad. This is defined by the pad-pad capacitance and Can be measured in the lab. Werner Riegler CERN, November 2003

Crosstalk Threshold (fraction of MEDIAN) 1% 2% 3% 4% 5% 6% 7% 8% 9% 10% 11% 12%. . 20% Werner Riegler CERN, November 2003

Threshold Calibration At the point where the hitefficiency is 50%, the threshold is at the MEDIAN Pulse Height. The voltage where the double gap efficiency is 95% marks the beginning of our plateau. The voltage where the double gap shows 99% efficiency is difficult to find. Therefore we define it as the voltage Where the single gap efficiency exceeds 90%. Knowing the gas gain curve allows To define threshold in terms of Fraction of the MEDIAN signal. Easy to obtain ! Werner Riegler CERN, November 2003

Gas Gain No space charge effects up to 2. 75 k. V Gas gain doubles for V of 106 V Werner Riegler CERN, November 2003

Crosstalk >95% efficiency if the threshold is at <15% of the median signal. >99% efficiency if the threshold is <7% of the median signal. At 2. 65 k. V threshold is at 5% of the median signal At 2. 75 k. V threshold is at 2% of the median signal !!!! The large crosstalk is real ! The double cathode Readout and the change from 1. 5 mm to 2 mm pitch brought us to the edge of the specifications ! Werner Riegler CERN, November 2003

High Rate Tests Inefficiency due to signal pileup. Since the muon trigger uses a 5 out of 5 coincidence, each of the 5 stations has to be >99% efficient. Therefore the signal width is a crucial number. It is not only determined by the electronics, there is a detector intrinsic Dead time due to arrival of the electrons. Since we use an OR of two frontend channels per station, the rate of correlated hits is the crucial number. 1. 5 mm pitch, Arrival time of the last electron is 25 ns. For uncorrelated hits, we still have 99% efficiency per station even if one frontend (double gap) has only 90% efficiency. Out goal is a dead time of <50 -60 ns. In addition to the deadtime (geometrical) we have of course some baseline fluctuations … Werner Riegler CERN, November 2003

High Rate Tests Positive Amplifier Negative Amplifier Am 241 is definitely a ‘worst case’ background signal (60 ke. V gamma) Werner Riegler CERN, November 2003

Charge/Hit at GIF Cs 137, 662 ke. V gammas Dividing the total chamber current by the count rate at 7 f. C threshold. The MIP charge is calculated by assuming 100 e-/cm and a measured gain curve, It is not a very reliable number …. . Werner Riegler CERN, November 2003

TDR Numbers assuming correlations from LHCb 2000 -089 Worst case behind the Calorimeter: 870 k. Hz Cathode, 1150 k. Hz Wires Werner Riegler CERN, November 2003 Station 1 doesn’t even work on paper

High Rate Tests at GIF In the experiment we will have high energy muons in presence of ‘photon’ (electron) background. The ideal situation is the muon beam at GIF. We didn’t have time to do this test – next chance only may next year. There is another way of testing the high rate behaviour I. e. signal pileup and baseline fluctuations – S-curve in presence of the background particles. Werner Riegler CERN, November 2003

High Rate Tests at GIF Chamber was positioned very close to the source. Threshold set to 7 f. C like in the T 11 testbeam. At out working Point of 2. 5 k. V we find exactly the maximum rates expected in the experiment (behind Calo) 1255 k. Hz wires 920 k. Hz cathodes Rate increases with HV because of the Compton spectrum … The steep increase on the Cathodes is due to the crosstalk Werner Riegler CERN, November 2003

S-Curve at High Rate Inject a signal delta signal on the pad and count the coincidence of the Chamber output signal with a correlated 20 ns gate. With source off one gets the ‘standard S-curve. With source on one gets all the information on rate, efficiency and baseline fluctuations. Baseline Efficiency Derivative gives the noise+baseline Fluctuation. Rate Werner Riegler CERN, November 2003

S-Curves at GIF 0, 2. 5, 2. 65 k. V Werner Riegler CERN, November 2003

Efficiency >99% efficiency at low rate Efficiency About 4% ‘geometric’ Efficiency loss at 2. 65 k. V and 1. 5 MHz ! Compatible with <50 ns deadtime. ! Werner Riegler CERN, November 2003

Noise Derivative of the S-curve gives the ‘Baseline Probability’ (Noise+Baseline fluctuations) Noise increases ‘slightly’ with the rate. Has to be evaluated more carefully … 0, 2. 5, 2. 65 k. V Werner Riegler CERN, November 2003

Conclusions u Up to now, CARIOCA 10 works according to specifications. u Still missing: Analog shapes, test pulse feature, input resistance, radiation tests, input protection, large pulse baseline recovery, …. u DIALOG will arrive Feb 1 st 2004 There is still enough time for CARIOCA tests. u In case we will find a problem on CARIOCA 10 we will have to consider a submission in Q 1 of 2004 which would shift our milestones but would not kill us. u Francis Anghinolfi agreed to do the design changes in case it is necessary. u The DIALOG still contains the ASDQ features, I. e. we are still free to chose …. . u We have to understand M 1 and all background rates much better u We should by no means exceed 1 MHz rate/fronted. Werner Riegler CERN, November 2003