Optimization of the ATLAS Muon Detector Readout forhigh counting rates

Sebastian Ott

July 21, 2013

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 1 / 22

Table of Contents

1 ATLAS-Detector at the LHC

2 The ATLAS Muon Detector

3 Optimization of the Moun Detector

4 Test of new electronics

5 Conclusions

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 2 / 22

LHC

Proton-Protoncollision at7 - 8 TeV (2012)Aim of energyincrease:13 TeV (2015)Design luminosity:1034 cm−2s−1

(2015)Luminosityincrease to7*1034 cm−2s−1

(2023)

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ATLAS

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 4 / 22

ATLAS Monitored Drift Tube (MDT)-Chamber

Tube diameter 30 mm(currently mounted)Gasmixture Ar/CO2 (93/7)Pressure: 3 barVoltage: 3080 VMax. drifttime: 700 nsNonlinear r-t-relationBackground rate capability:300 kHz/tube (500 Hz/cm2)

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 5 / 22

Upcoming Requirements

Background:PhotonsNeutrons

Background∝ luminosity

Higher signal rates

⇒ In some regions the MDT-chambers will come to their limits

Rates in Hz/cm2

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 6 / 22

Improvement of the MDT-Chambers - sMDTReducing the diameter to 15 mm

Shorter max. drifttime

⇒ Deadtime can be reduced⇒ Fewer masking effects

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 7 / 22

Improvement of the MDT-Chambers - sMDTReducing the diameter to 15 mm

More tubes per chamber

⇒ Lower occupancy

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 8 / 22

Improvement of the MDT-Chambers - sMDTReducing the diameter to 15 mm

Less space charge fluctuations

⇒ Better resolution

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 9 / 22

Improvement of the MDT-Chambers - sMDT

e−-Ion-pairsFast e− signal isinterestingMultiple thresholdcrossings for one Muonpossible

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 10 / 22

Signal Pile-Up

Large undershot from bipolarshapingShift of a second thresholdcrossingEven loss of second hit ispossibleEfficiency loss

⇒ Still more potential inthe sMDT

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Signal Pile-Up

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 12 / 22

Signal Pile-Up

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 13 / 22

Base Line Restauration

The aim is to get rid of the long signal tail

⇒ Negative signal part is unwantedSimplified idea:Insertion of a diode

⇒ Negative part is ’cut’ off⇒ Lower deadtime

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 14 / 22

Testsetting

Testboard with BLR electronicsDelta pulse

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 15 / 22

First Test of Readout Electronics with BLR

Rectangular signal from pulse generatorFeeding the input via capacitor

⇒ Delta pulse at the input of the electronic

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First Test of Readout Electronics with BLR

Only a small undershotFast base line restauration

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 17 / 22

First Test of Readout Electronics with BLR

No pile-upNo loss of amplitude

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 18 / 22

First Test of Readout Electronics with BLR

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 19 / 22

First Test of Readout Electronics with BLR

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 20 / 22

Conclusion and Summary

Signal pile-up lowers efficiencyShaping has to be improvedChip with BLR

Shows expected characteristicLowers deadtimeShortens the undershot

Test measurements on a chambersDevelopment of a new adjusted chip

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 21 / 22

Thank you for your attention

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