optimization of the atlas muon detector readout for high … · 2013. 7. 21. · sebastian ott...

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)

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 3 / 22

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

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 11 / 22

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

Sebastian Ott Optimization of the ATLAS Muon Detector Readout for high counting ratesJuly 21, 2013 16 / 22

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

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