Pixel Offline Status Jianchun Wang Syracuse University 10/28/04, Pixel testbeam meeting

2 To Do List Of Last Month Finish alignment and ntuple generating. Skim all data files with hit trigger.  Include real ADC-charge conversion once Lorenzo finishes the calibration. Currently the conversion uses a set of value I chose long time ago. And we have only charge weight, no eta correction.  Put more realistic expected resolution. Currently we use our knowledge from last test beam. We need chi2 value without DUT hits for track selection. If you choose very loose chi2 for now it is not a big issue. Update offline instruction.

3 Tracking without DUT  We need tracking quality of the telescope without DUT. In this way we can select very good track without worrying bias the results.  Extra parameter to indicate DUT: dut_plane(7)=1.  Parameters for user event trigger: max_miss_planes, max_miss_teles.  In NTUPLE the parameters are: chisq_t, cl_t, ndof_t.  Suggested track quality selection: cl_t > 0.01

4 Issue of 1-column Hits  In Kalman filter we treat pixel hits as two strip hits (strip_equivalent): one Y, and one X.  For X planes an 1-column Y strip_equivalent hit is not taken into fit, whereas 2-column hit is included. The resolutions are ~100  m and ~10  m respectively. Same to X hits of Y planes.  This causes some problems if you want to estimate tracking resolution naively. The Kalman filter provides a projected error of the hit.  The 1-column strip_equivalent hit does not help tracking resolution. It makes calculation of chi2 not reasonable because the distribution is not a Gaussian function.  We will continue skipping those hits.

5 FPIX1 Calibration  Hits with multiple-pixel can have charge weighting in determining the position.  FPIX1 planes are not as good as FPIX2. We need to include inefficiency in MC simulation of tracking resolution.  Absolute calibration is needed. Parameters cleared, recalculated, copied. Plane 5, a relatively good plane. PlaneThreshold 0 (Ke)Noise (Ke) (!) (!)0.69

6 Multiple Tracks in One Event Track generation in MC is tuned to real data, run  Beam fully covers all detector planes.  Number of tracks: =0.8 for full coverage.  Beam direction spread:  x =0.130mrad,  y =0.152mrad. Percentage Monte Carlo Run 1981

7 Multiple Scattering MaterialFIX1FPIX2 X/X0 (  10  ) ROC 450  m200  m 4.81 / 2.14 Sensor 275  m250  m 2.94 / 2.67 PCB/G  m 7.73 Copper 20  m 1.40 Al 20  m (?) 0.22 Myllar 200  m (?) 0.70 Sum17.8 / 14.9 Effects of multiple scattering: A track starting at plane 3, the spread at plane 11 (  z~90cm) is  x =  y =22.7  m. The tracking error on DUT planes changes from 3.3  m to 3.9  m.

8 Comparison of ADC Value Percentage Monte Carlo Run 1981 Monte Carlo Run 1981 Absolute calibration is needed. Plane 3 Plane 7

9 Comparison of Number of Pixels Percentage Monte Carlo Run 1981 Monte Carlo Run 1981 Plane 3 Plane 7

10 Comparison of Resolution Run 1981 MC total MC tracking More studies are coming.

11 Comparison of Resolution Real Data MC total MC tracking There is still about 2  m difference.

12 Summary  Recent activities of offline code are mainly focused on tuning MC simulation.  The number of hit pixels and X resolution is still different from real measurement.  I will continue this work.  The eta correction and realistic resolution are yet to be included.