Pixel Results from CRAFT09 U. Langenegger (PSI), G. Giurgiu (JHU) Pixel General Meeting November 10, 2009

2 CRAFT09 Analyses - Gain calibration + Validation – R. Rougny (Antwerpen), U. Langenegger (PSI) - Pixel hit efficiency - L. Mucibello, R. Rougny, N. van Remortel (Antwerpen) - Pixel hit resolution – K. Ulmer (Colorado) - BPIX Lorentz angle – M. Ivova, V. Chiochia (Zurich) - FPIX Lorentz angle – A. Kumar, A. Godshalk, A. Kharchilava (Buffalo) - Data/MC comparison – A. Jaeger, V. Chiochia (Zurich), M.Swartz (JHU) - All analyses done with most recent CRAFT09 reprocessing /Cosmics/CRAFT09-TrackingPointing-CRAFT09_R_V4_CosmicsSeq_v1/RAW-RECO

3 Gain Calibration R. Rougny (Antwerpen), U. Langenegger (PSI) - Pixel thresholds minimized before CRAFT09 → procedure led to significant fraction of negative BPIX pedestals - After CRAFT09, detector settings changed to fix negative pedestals (Ben Kreis, D. Kotlinski) → new gain calibration taken (run ) → fraction of negative pedestals indeed negligible in new calibration: BPIX FPIX

4 Gain Calibration Validation U. Langenegger (PSI), R.Rougny (Antwerpen) - Analyze post-CRAFT09 data to validate new gain calibration CRAFT09 data - Fraction of post-CRAFT09 data - No problems seen Runs

5 In you can find a higher statistics version of the CRAFT09-II gain calibration validation. This is still without the SP skim. CRAFT09-II cluster charge: BPIX Landau+Gauss: FPIX Landau+Gauss: reprocessed CRAFT09 SP skim cluster charge: BPIX Landau+Gauss: FPIX Landau+Gauss: The MPV have come down a bit in both BPIX and FPIX, the effect of the slightly lowered gains, visible in the overlayed offline payload comparison for the new and previous gain calibration runs The relative width has decreased (increased) slightly for the BPIX (FPIX). The gain calibration looks good Gain Calibration Validation U. Langenegger (PSI)

6 Data / MC Comparison A. Jaeger, V. Chiochia (Zurich)

7 Data / MC Comparison – Cluster Charge A. Jaeger, V. Chiochia (Zurich) - Fair agreement between data and MC - Disagreement at low charge could be explained by lower thresholds in MC than in data - Andreas will produce MC with higher thresholds which match data barrel

8 Data / MC Comparison – Pixel Charrge A. Jaeger, V. Chiochia (Zurich) barrel

9 Data / MC Comparison – Pixel Hit Probability A. Jaeger, V. Chiochia (Zurich) - Pixel hit probability calculated as chi2 probability of the matching between the observed cluster shape and the expected template - Fair qualitative agreement between data and MC → important test since we plan to use pixel probability to improve tracking (remove bad hits, split merged clusters…) - Work in progress - re-digitize MC with higher thresholds to match MC - optimize phase space to emulate collisions better (~4000 electrons) barrel

10 Pixel Hit Efficiency L. Mucibello, R. Rougny, N. van Remortel (Antwerpen)

11 Pixel Hit Efficiency L. Mucibello, R. Rougny, N. van Remortel (Antwerpen) Layer 1 Layer 2 Layer 3 White boxes = known bad modules low statistics Eff = N valid / (N valid + N missing ) Pixel sensor efficiency ~ 98.3 – 98.5% - Will investigate pixel efficiency with strip seeded tracks to avoid biases in efficiency

12 Pixel Hit Resolution K. Ulmer (Colorado) - Pixel hit resolution measured in CRAFT09 using the “double difference” method - Compare measured resolution with predicted errors from template based cluster parameter estimator (CPETemplate) - Resolution in microns : reprocessed original processing measured predicted measured predicted X 18 ± 1 15 ± 1 19 ± 3 15 ± 1 Y 26 ± 1 23 ± 1 32 ± 2 25 ± 2 - Measured resolution about 10-20% worse than predicted by CPE - Will repeat measurements with much better statistics with collisions - Will correct CPE predicted errors to match observed resolution

13 BPIX Lorentz Angle – Cluster Size Method M. Ivova, V. Chiochia (Zurich) E - Good agreement LA measured in latest and first processing as well as with the PIXELAV Simulation cot(  ) min = / – latest CRAFT09 reprocessing cot(  ) min = / – first CRAFT09 processing cot(  ) min = / – PIXELAV simulation (M. Swartz) B field ON B field OFF LA consistent with zero within 2   Lorentz ≈ 22°

14 FPIX Lorentz Angle – Cluster Size Method A. Kumar, A. Godshalk, A. Kharchilava (Buffalo) - Good agreement LA measured in latest and first processing as well as with the PIXELAV Simulation cot(  ) min = / – first CRAFT09 reprocessing cot(  ) min = / – latest CRAFT09 processing cot(  ) min = / – PIXELAV simulation (M. Swartz)  Lorentz ≈ 5° LA consistent with zero B field ON B field OFF

15 FPIX Lorentz Angle – Grazing Angle Method A. Kumar, A. Godshalk, A. Kharchilava (Buffalo) - Buffalo group also measured FPIX LA using grazing angle method in CRAFT08 and got good agreement with cluster size method → nice proof of principle 3.75° ± 0.41° - grazing angle 3.95° ± 0.39° - cluster size - This is important since with collisions cluster size method is not adequate - With collisions grazing angle method will be used for BPIX - For FPIX neither grazing angle nor cluster size are optimal with collision tracks → might have to rely on cosmics only Depth (  m ) Avg. Drift ( m m)

16 Conclusion - Gain calibration in place and validated with post CRAFT09 data - Lorentz angles measured and in agreement with previous processing and with PIXELAV simulation - Pixel sensor efficiency ~98.5% - Next step: use strip seeded tracks to avoid biases - Reasonable data/MC agreement when collision like cosmic tracks selected but some cosmic specific effects not simulated - Pixel hit resolution within 10-20% from expectation - Will repeat with collisions and adjust predicted errors if needed

17 Backup Slides

18 Gain Calibration Validation U. Langenegger (PSI), R.Rougny (Antverpen)

19 CRAFT09 data - Fraction of post-CRAFT09 data - No problems seen Gain Calibration Validation U. Langenegger (PSI), R.Rougny (Antverpen)

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