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Since last time I u pdated the CARIOCA dead time values

Since last time I u pdated the CARIOCA dead time values (and the induced inefficiency for background and muon hits ) I simulated the inefficiency i nduced by the DIALOG formation time. G. Martellotti 12/06/2014. 1. REMIND. CARIOCA dead-time & inefficiency.

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Since last time I u pdated the CARIOCA dead time values

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  1. Since last time • I updatedthe CARIOCA dead time values • (and the inducedinefficiency for background and muonhits) • I simulated the inefficiencyinduced by the • DIALOG formation time G. Martellotti 12/06/2014 1

  2. REMIND CARIOCA dead-time &inefficiency G Martellotti, G. Penso, D. Pinci The countingrates on the bi-gap physicalchannelcountersweremeasuredatdifferentluminosities (0.4 - 0.5 - 0.6 - 0.8 - 1) x 1033 M2 station C side hasbeenanalysed FIRST STEP (Data) - Measureinefficiency of particlecounting - Extractthe inefficiencyfraction due to CARIOCA dead-time δcar SECOND STEP (Monte Carlo) - simulate the beam time structurefolded with the chamber time response and dead time variance - Evaluatethe <δcar> necessaryto generate suchinefficiency - From this<δcar> evaluatethe inefficiencywewillhaveat 40 MHz 2

  3. dead time inefficiency Subtractingthe countinginefficiency due to ‘’granularityeffect’’ (ifwehave > 1 particle/pad, the countercountsonly 1)  Inefficiency of the physicalchannelas a function of its rate. The inefficiency can be expressed in terms of the effective dead-time δeffdue to the CARIOCA dead-time folded with the BC time sequence and the detector time response. Ifwemeasure the rate in GHz, the slopeisdirectlyexpressed in ns δeff= - 52ns for wires - 65ns for cathodes R*/Rh = (1- δeffR*) inefficiency = δeffR* (δeff in ns, R*=rate measured/0.7 in GHz) 3

  4. Time response of the bi-gap chamber Weare interestedin the inefficiency for muons, butdead time isstartedby background hitswhosetime distributioniswider (itisdominatedby the ‘’single gap track’’ hits  the time distribution of the bi-gap should be similar to the one of the quadri-gap). I used the time distributionmeasured for MinBias TAE events(LHCb-PUB-2011-027) Smoothedcorrecting for the TDC bug at the 25 ns intervaledges (ns) 4

  5. BCR = 20 MHz <δcar> Wires 78 ±3 ns Cathodes 91.5-3.5+2 ns Background hits in the current BC. Measured FE counterinefficiency on vertical scale average CARIOCA dead time <δcar> on the horizontal scale CARIOCA dead time has a large variancedepending on the large variance of the chargereleased by the background tracks. Here for simplicity a gaussianwith σ =9ns hasbeenassumedbut the realvarianceismuchlarger  the smoothingisevenlarger inefficiency(effectivedead time) <δcar> ns 5

  6. BCR = 40 MHz Inefficiency for background hits(FE counters) Full smoothingat 40 MHz The inefficiencyinduced by dead time asexpectedishigher w.r.t. the case of 20 MHz 60/52 for wires 74/65 for cathodes inefficiency(effectivedead time) <δcar> ns 6

  7. BCR = 40 MHz The inefficiencyinduced by dead time ishigherfor muonhits w.r.t. background hits (the time distribution for muonsissharper and the averagevaluelower) I don’thavenow the response of a bi-gap for muons (do wehaveit?) Here I assumed a gaussian: Peak 11ns, σ = 5ns The inefficiencyfor muonsislargerby ~ 6.5 ns - IfI assume a peakvalueat10ns  7.5 ns - IfI assume a peakvalueat13ns  4.5 ns In case of CARIOCA dead time the differenceisrelatively small (orderof 10%) In case of DIALOG  muchlargerdifference Inefficiency for MUONS inefficiency(effectivedead time) <δcar> ns 7

  8. M2R3 X Y= 24x4=96 phys. channels 24+ 4 logic. stripsper TS Area TS = 60x50=3000 cm2 Inefficiencydue to a DIALOG formationtime= 18 ns =3.9 % at 5.4 kHz/cm2 (the average rate in the region) Here a gaussian with peakvalue= 11ns and σ= 5ns wasassumed for the time distribution of the muonhits in the bi-gap. A uniform rate in the trigger sectorwasalsoassumed. Thisisnotfullycorrect… neverthelessthisvalueissignificantlyhigher w.r.t. whatreported in the TDR (2.6 %) And whatisrelevantisthat, if I use the same time distributionused for the background hits, I get a muchsmallerinefficiency: 2.2 % (to be compared with 2.6%) Reconstructedhits HITS in the Trigger Sector Real particles Rate/cm2 (kHz) 8

  9. DIALOG formation time (σ=0) inefficiencyfor Muonhits (in terms of effective dead time) Here I assumeda gaussianwith peakvalue = 11ns (-1.5ns), σ = 5ns DIALOG INEFFICIENCY (eff. dead time) formation with muonpeakat -2.5ns -1.5 +0.5 12.5 ns 2.7 ns 2.1 1.1 15 4.3 3.6 2.3 17.5 6.6 5.7 4.9 20 9.2 8.1 6.1 inefficiency(effectivedead time) DIALOG formation time 9

  10. SUMMARY • The efficiencyisstronglydependent on the DIALOG formation time • Itisalsostronglydependent on the peakvalue of the muon time distribution • The inefficiencyseems to be higher w.r.t. whatreported in TDR and in certainregionsisquite large (see the case of M2R3) • If the inefficiencyis large wewillhave(significant) sistematiceffects (In the same detector zone wehavemuons with differentmomenta and differentchargearrivingwith a different TOF  differentpeakvalue) • Can wefurther reduce DIALOG formationtime ? • IncreasenODEnumber in manyregions 10

  11. Spares

  12. Average 13ns Average 10ns

  13. average= 13ns (+0.5) average= 10ns (-2.5)

  14. M2R3 Background hit Time distribution Time distribution of Background hits

  15. Simulation of • - Rate of reconstructed hit (with ghosts) • - Efficiency • procedure: • # Considerthe Trigger Sector (TS) geometry of a givenregion • counting rate in the single FE (starting from the foreseenparticle rate per cm2 and usingthe averagecorrelationfound in the station with AND/OR measurements) • Inefficiency due to CARIOCA dead time (and DIALOG formation time) • Averagenumber of logicalpads in theTShit by particles (I assumed a uniform hit distribution in the TS) • Logicalpadsreconstructed(X & Y crossing)  ghosts

  16. Simulation input: Foreseenrates reported in TDR Rates of particles (no ghosts) atL=2x1033 Rates in kHz/cm2 • Note : • The effectsimulated of the new shielding to be addedat M2-inner hasbeen put in • The effect of the last shieldingalreadyaddedat M5R4, has to be evaluated and put in

  17. Simulationinput: Most of the hitsdetected in the chamberlayers are uncorrelated (the fraction of correlationstronglyaffectssimulationresults) In black the percentageof correlatedhitsmeasured (at2.76 TeV) on the physicalchannelcounters with the FE of the twolayers in OR - AND In blu the percentage of penetratingtracks (4 gaps) from ‘’Alessia’’MC

  18. From theseinputs  Logicalpadoccupancy (with ghosts) and inefficiency TS = 95 cm2 X,Y= 6+8 phys.channels 48 crossings EXAMPLE M2R1 Reconstructedhits (with ghosts) Assuming efficiency = 1 With inefficiency TS Particles Ghosts inefficiency Real particles The 3 redverticallinescorrespond to the ratesforeseen in the chamber of the regionhavingminimal, average, maximalpopulation Particle HITS not in dead time Logicalpadoccupancy inefficiency Rate/cm2 (kHz)

  19. logicalpadoccupancy with ghosts (%) in the mostcriticalregions (ε = 1 assumed) New padchambers M2R1 M3R1 : padsize X, Y/2 w.r.t. presentlogicalpad Modifiedreadout (from IB on) M2R3 M2R4 M5R4 : full paddetector (pad = logicalpad) M2R2 : verticalpadsize Y/2 Present detector ChambMin Aver Max M2R1 0.6 1.2 2.1 M2R2 0.3 1.1 2.6 M2R3 0.1 0.6 1.5 M2R4 0.1 0.3 1.2 M3R1 0.2 0.5 0.9 M5R4 0 5.7 22 ChambMinAver Max M2R1 1.6 4.0 8.7 M2R2 0.5 2.1 4.6 M2R3 0.1 0.8 2.7 M2R4 0.1 0.3 1.9 M3R1 0.4 1.3 2.7 M5R4 0.4 9.3 51 ChambMin Aver Max M2R1 1.6 4.0 8.7 M2R2 0.3 1.12.6 M2R3 0.10.61.5 M2R4 0.1 0.3 1.2 M3R1 0.4 1.3 2.7 M5R4 0 5.722

  20. M2R1 PRESENT DETECTOR (TS=95cm2) X,Y= 6+8 phys.channels per Trig. Sect. 48x8 crossings per chamber (0.63x3.1 ~ 2cm2) Inefficiency = 5, 11, 23 % at 162, 327, 590 kHz/cm2 Thisisnot the inefficiency for a muontrack. Thisisinefficiency for a single pad hit belonging to a muon Cross talk willincrease the efficiency for muontracks. The inefficiencyiscalculated for muonshittingcorrespondingpads in the twolayers(sligthlypessimistic for muonscrossing non projectivepads in the twolayers) Logicalpadoccupancy Rate/cm2 (kHz)

  21. M2R1 PAD DETECTOR X (x2), Y (x1/2) w.r.t. logicalpad 384 pads per chamber(1.26x1.6 ~ 2 cm2) M2R1 PAD DETECTOR 2 times X , same Y of logicalpad 192 pads per chamber(1.26x3.2 ~ 4 cm2) Inefficiency = 0.8, 1.6, 3.3 % at 162, 327, 590 kHz/cm2 Inefficiency: large improvement 0.4, 0.7, 1.5 % at 162, 327, 590 kHz/cm2 MisID: ~ the sameimprovementusing the usual FOI No furtherimprovementispossibleusing a smaller FOI. MisID:No ghosts  improvementusing the usual FOI (buthigheroccupancy of realparticles due to increasedefficiency) With thisYpadsize , one can use a smaller FOI with furtherimprovement. Pad occupancy Pad occupancy Rate/cm2 (kHz) Rate/cm2 (kHz)

  22. M3R1 PAD detector Xx2 , Y (#physchan. = #logicalpad/2) 192 pads per chamber(1.26x3.1 ~4 cm2) M3R1 present detector (TS = 109 cm2 ) X,Y= 6+8 phys. channels (48 crossings/TS) 384 crossingsper chamber (0.63x3.1 ~2 cm2) Inefficiency= 0.2, 0.6, 1.0 % At 39, 123, 216 kHz/cm2 MisID improvement (no ghosts) ~ same FOI can be used. Ineffic = 0.7, 3.2, 6.9 % At 39, 123, 216 kHz/cm2 Pad occupancy Logicalpadoccupancy Rate/cm2 (kHz) Rate/cm2 (kHz)

  23. M3R1 PAD detector Xx4 , Y (#phys. chan. = #logicalpad /4) 96 pads per chamber(2.5x3.1 ~ 8 cm2) Reducinggranularity to 96 padsInefficiencyincreases = 0.3, 1,2, 2.3 % Inefficiency can be recovered building the pad detectorwith smallerphysicalchannels OR-ed in the DIALOG (withoutincreasing output cables) Whatcannot be recoveredis the increase of MisIDif FOI must be increasedto savemuonmatchingefficiency Pad occupancy

  24. M2R2 present detector (TS=380 cm2) X,Y= 12+16 phys.ch. =12 + 4 logic. per TS 48x4=192 crossings/chamber(1.26x6.3~8 cm2) M2R2 PAD DETECTOR X=2X, Y=1/2Y of logical (itisconvenient) 192 pads per chamber (2.5x3.1 ~ 8 cm2) Inefficiency : 0.8, 3.3, 6.8 % At 15, 52, 97 kHz/cm2 Efficiency– large improvement 0.1, 0.6, 1.1 % MisID Improvement (no ghosts) and possiblefurtherimprovement reducing YFOI Logicalpadoccupancy Pad occupancy Rate/cm2 (kHz) Rate/cm2 (kHz)

  25. M2R2 PAD DETECTOR X=2X, Y=Y of logicalpads 96 pads per chamber (2.5x6.3 ~ 16 cm2) Efficiency= 0.3, 1.3, 2.4 % MisID Improvement (no ghosts) But, going back to the Y padsize = 6.3 cm, wehavelost the possibility of reducing FOI having ~ the muonmatchingefficiency. Pad occupancy Rate/cm2 (kHz)

  26. M2R4 presentdetector (TS=12000 cm2) X Y= 24x4=96 phys. channels 24+ 4 logic. stripsper TS Area TS = 120x100=3000 cm2 Inefficiency from DIALOG 0., 1.7, 7.4 % at 0.12, 0.63, 2.6 kHz/cm2

  27. M5R4 present set up (TS=18480 cm2) X,Y= 24+4 phys. ch. = 6+4 logic. Ch. per TS 24 crossings per TS (~770 cm2) Inefficiency from DIALOG (formation 18ns)  to check (TAE behavedifferently) Also DIALOG dead time simulated.Inefficiency = 1.3, 9, 30 % at 0.2, 2, 9 kHz/cm2 ONLY CARIOCA dead time inefficiencysimulated 2.3 % at 9 kHz Pad occupancy HITS in the Trigger Sector Rate/cm2 (kHz) Rate/cm2 (kHz)

  28. In M2R1, M2R2, M3R1, M3R2 inefficiencycomes from CARIOCA dead time depending on the physicalchanneloccupancy (particle rate/cm2 and channel area) In the otherregionswherewehave a PAD detector with padsOred in the readout, the largestinefficiencycomes from the ‘’DIALOG dead time’’ Inefficiencies of mysimulation (differentdefinitionsbut….) Inefficienciesreported in TDR (Giacomo) Min Aver Max 5.0 11.0 23.0 % 0.8 3.3 6.8  (to add DIALOG ineff) 0.7 3.9 9.3 0.0 1.7 7.4 0.7 3.2 6.9 1.0 9.0 30 %

  29. STATION hit rate in the cm2 Strip strips (MHz) Vertical Horizont RATES kHz/cm2 RATES kHz/cm2 RATES kHz/cm2 4 gaps 2 gaps 1 gap Corr % (1+corr)/2 (1+3corr)/4 Min Aver MaxMinAver MaxMinAver Max M2R1 7 162 327 590 .54 87 175 316 .30 49 98 177 16 – 12 5.2-3.9 M2R2 9 15 52 97 .55 8.2 28 53 .32 4.8 17 31 31 – 23 M2R3 15 0.9 5.4 13.4 .58 0.5 3.1 7.8 .36 .32 1.9 4.8 125-750 0.7-4.1 M2R4 32 .12 .63 2.6 .66 .08 0.4 1.7 .49 .06 .31 1.3 500-3000 0.3-1.9 M3R1 4.5 39 123 216 .52 20 64 112 .28 11 34 60 18 – 14 2.2-1.7 M5R4 12 .23 2.1 9.0 .56 .13 1.2 5.0 .34 .08 .71 3.1 3080-4620 6.5-9.7

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