Software for Twin Tubes

1
Software for Twin Tubes

• A. Koutsman, P. Kluit, N. van Eldik, E. Moyse
• 17 april 2008

• Twin Tubes Principle in ATLAS
• Software implementation
• Future

2
Twin Tube Principle

• Two MDT tubes interconnected at the high voltage
  end
• Read-Out on both ends
• Difference in time gives position along the tube
• Built-in delay in HV-jumper
• Twin tubes installed in region with limited
  trigger chamber coverage BOL4A13 BOL4C13
• No change needed for DAQ software
• Helps tracking in f
• independent measurement
• reduce fake hits
• if two tracks through one trigger chamber twin
  coordinate resolves ambiguous solution

from NIM-paper
Twin time resolution (ns)
http//www.nikhef.nl/pub/experiments/atlaswiki/in
dex.php/Twin_Tubes
nomenclature Prompt hit (1) or Twin hit (2)
3
Digitization

• MuonDigitization/MDT_Digitization/MDT_Digitizer
• If an MdtSimHit is from a BOL-chamber simulate a
  twin hit Identifier, drifttime and ADC-value
• Calculate twin tube drifttime using
  drifttime(tprompt), signed(with respect to
  RO-side) hit position along tube (x),
  tube-length(L), propagation-speed in both
  tubes(vprompt, vtwin), HV-delay(?0) and
  TOF-time(tTOF)

• Smear ttwin with twin-resolution for more realism
• Insert into MDT_SortedHitVector, sort and store
• Two new job-options to activate twin tubes
  simulation UseTwin, UseAllBOLTwin(only for
  testing)

4
Write MdtPrepRawData

• MuonCnv/MuonRdoToPrepData/MdtRdoToMdtPrepData
• If hit is from a BOL-chamber find prompt and
  twin tube, calculate unsigned position along tube
  (xgeo), fill a new MdtPrepData with driftradius
  and xgeo for prompt hit
• Calculate xgeo using sign(1), tubelength(L),
  twin pair time difference(?t), propagation-speed
  in both tubes(vprompt, vtwin), HV-delay(?0)

• xgeo error is set at measured ?t-resolution/propag
  ation-speed
• Three new job-options to store twin tube PRD
  UseTwin, UseAllBOLTwin (only for testing),
  Use1DPrepDataTwin (ignore twin hit/info)
• Store twin PrepRawData ? new class
  MdtTwinPrepData
• Calibrate ? new class MdtTwinCalibrationSvc

5
New Classes

• MdtTwinPrepData

Original MdtPrepData Identifier IdentifierHash Lo
calPosition (driftradius, 0) ErrorMatrix 1X1
(error radius) MdtReadoutElement TDC-value ADC-va
lue MdtDriftCircleStatus
MdtTwinPrepData Identifier (prompt
tube) IdentifierHash (prompt tube) LocalPosition
(driftradius, xgeo) ErrorMatrix 2X2 ( 0,0
error radius,
1,1 error xgeo ) MdtReadoutElement
(prompt-tube) TDC-value (prompt tube) ADC-value
(prompt tube) TDC-value (twin tube) ADC-value
(twin tube) MdtDriftCircleStatus

• MdtTwinCalibrationSvc

Return drifttimeprompt, drifttimetwin
propagation speedprompt, propagation speedtwin
slewingtimeprompt, slewingtimetwin
6
Test Truth vs. PrepRawData

• Are the hits from twin tubes correctly propagated
  through the whole muon reconstruction chain?
• Compare hits using CalibrationNtuple
• SDO Truth?positionAlongTube()
• TwinPrepData?localPosition.x()
• xgeo the twin coordinate in Geomodel
  coordinate frame

7
Summary and Outlook

• Twin tubes installed on two chambers in ATLAS
• Digitization of twin tubes complete ? ready to
  commit
• MdtPrepRawData almost complete ? new twin classes
  to be written
• MdtTwinPrepData
• MdtTwinCalibrationSvc
• 14.2.0
• Write twin calibration software
• Testing of muon reconstruction chain using
  MdtTwinPrepData