2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 11

Crosstalk Removal to Crosstalk Removal to Improve Muon dE/dX Improve Muon dE/dX

MeasurementsMeasurements

Leo Jenner, UCLLeo Jenner, UCL

2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 22

In briefIn brief

Crosstalk removal Crosstalk removal algorithmalgorithmComparison of Comparison of Tracking + Tracking + Crosstalking to MC Crosstalking to MC truthtruthSome hitches…Some hitches…Preliminary Preliminary comparison of MC to comparison of MC to datadata

2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 33

A Cosmic Ray MuonA Cosmic Ray Muon

Crosstalk removal helps with Tracking and is also important for correcting muon dE/dX for relative calibration of the MINOS detectors.

2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 44

CrossTalk AlgorithmCrossTalk AlgorithmWork through all the hits in a given pair of Work through all the hits in a given pair of planes and look at the 8 pixel window planes and look at the 8 pixel window around each ‘test’ hitaround each ‘test’ hitSum the charge and identify the largest hit Sum the charge and identify the largest hit in the windowin the windowThe test hit is flagged as crosstalk if its The test hit is flagged as crosstalk if its charge is less than the sum of the pixels charge is less than the sum of the pixels around it, multiplied by a user definable around it, multiplied by a user definable factor. This is usually set to 1 for factor. This is usually set to 1 for beam/cosmic muons since low energy beam/cosmic muons since low energy deposition combined with photon statistics deposition combined with photon statistics can lead to crosstalk with very comparable can lead to crosstalk with very comparable energy to real hitsenergy to real hits

The Crosstalker currently runs as a module before the CalDet muon tracking codeThe Crosstalker currently runs as a module before the CalDet muon tracking codeTesting is taking place on Crosstalking Monte CarloTesting is taking place on Crosstalking Monte Carlo

2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 55

Number of Crosstalk hits: Truth vs TrackedNumber of Crosstalk hits: Truth vs Tracked

The crosstalker finds about 82% of the crosstalk The crosstalker finds about 82% of the crosstalk hits as I’ve opted for a high purity (>90%)hits as I’ve opted for a high purity (>90%)

2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 66

dE/dX from Monte Carlo (Truth and Tracked)dE/dX from Monte Carlo (Truth and Tracked)

2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 77

Comparison of MC truth to MC+TrackingComparison of MC truth to MC+Tracking

For the most part there is good agreement…For the most part there is good agreement…

2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 88

Number of Hits: Tracked/TruthNumber of Hits: Tracked/Truth

•A close up of the last few planes shows the discrepancy increasing

But only 0.32% of But only 0.32% of events go to plane 54 events go to plane 54 or more…or more…

2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 99

Last Plane HitLast Plane Hit

Some of the hits at the end of the track seem to go Some of the hits at the end of the track seem to go missing after tracking…missing after tracking…

2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 1010

Very curvy muonsVery curvy muons

In the third plot along the two blue hits at the end of the track are genuine track hitsIn the third plot along the two blue hits at the end of the track are genuine track hitsMaybe the muon curves sharply to the left and travels in the air gap between planesMaybe the muon curves sharply to the left and travels in the air gap between planesThe tracker doesn’t nominally find the last hit because it falls outside of the search The tracker doesn’t nominally find the last hit because it falls outside of the search windowwindowNoise also creates spurious hits at the end of the trackNoise also creates spurious hits at the end of the track

2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 1111

Preliminary comparison to dataPreliminary comparison to data

Quite low statistics but it still looks a bit oddQuite low statistics but it still looks a bit odd

2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 1212

Data - Last Plane HitData - Last Plane Hit

Even with cut: 10<first Even with cut: 10<first strip hit <13strip hit <13

‘PS’ Muons, Other off momentum muons coming down the beampipe

2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 1313

ConclusionConclusion

More work to do to optimise Tracking and More work to do to optimise Tracking and Crosstalk removal using Monte CarloCrosstalk removal using Monte Carlo

Fold crosstalk back into real hits to further Fold crosstalk back into real hits to further improve MC dE/dXimprove MC dE/dX

Apply crosstalk removal to data Apply crosstalk removal to data

2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 1414

2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 1515

AnomaliesAnomalies

Entry: 2340943 Record: 3107 End: A Plane: 48 Entry: 2340943 Record: 3107 End: A Plane: 48 Strip: 8 HitBit: 786432 PE: 5.86536 TrackEnd: B Strip: 8 HitBit: 786432 PE: 5.86536 TrackEnd: B Plane: 48 Strip: 8 HitBit: 786432 PE: 7.3501 Plane: 48 Strip: 8 HitBit: 786432 PE: 7.3501

Entry: 2340944 Record: 3107 eventnum: 3107 Entry: 2340944 Record: 3107 eventnum: 3107 Entry: 2340945 Record: 3107 eventnum: 3107 : Entry: 2340945 Record: 3107 eventnum: 3107 : End: B Plane: 54 Strip: 10 End: B Plane: 54 Strip: 10 HitBit: 0HitBit: 0 PE: PE: 0.9357730.935773

Entry: 2340946 Record: 3107 eventnum: 3107Entry: 2340946 Record: 3107 eventnum: 3107

There is an unphysical hit of nearly 1pe… it’s ignored by the truth (see above) but the tracker finds it

2 Oct 20032 Oct 2003 UCL 2nd Year TalkUCL 2nd Year Talk 1616

Number of Hits Truth vs TrackedNumber of Hits Truth vs Tracked

Plane No. MC Tracked MC Truth Ratio Comment19 9802 9868 1.007 Typical Plane48 6163 6267 1.017 Lph mean here49 4208 4332 1.0350 2267 2357 1.0451 881 931 1.05852 236 289 1.2253 73 104 1.4254 23 40 1.7455 6 25 4.1556 3 24 857 0 12 -58 0 12 -59 0 6 -60 0 6 -