9th October 2003James Loken – Oxford University1 SCT X-ray Alignment Software A First Look

9th October 2003James Loken – Oxford University2 Complete Tomograph -set-up-

9th October 2003James Loken – Oxford University3

9th October 2003James Loken – Oxford University4

9th October 2003James Loken – Oxford University5 Hardware Layout  Head ess. as for complete system  X-ray tube  Collimation system, ~80  m and ~330  m wide beams  Rotary stage, precise to 0.36’’

9th October 2003James Loken – Oxford University6 Parameters: R, Ψ 1 and Ψ 2 Measured: Φ 1 and Φ 2 Result coordinates: r and φ Accuracy achieved with the XTomo2D (at r ~ 500mm) : σ(rφ) = 5 μm σ(r) = 20 μm [see NIM, A457 (2001) 43-51] Measuring tool: AEROTECH Rotary Stage, σ(φ) = 1’’ Two Dimensional X-ray Triangulation Scheme

9th October 2003James Loken – Oxford University7 Detector Orientation

9th October 2003James Loken – Oxford University8 X-ray Alignment  Current Methods  Simulation (of Hits)  HitToStrip  (real data could enter here)  StripToHit  Reconstruction (from Hits)  Analysis  Future  Incorporate Position and Tilt sensors  Diagnostic tools for Problem Solving  Calibration of X-ray Gun CopyHits (for debug)

9th October 2003James Loken – Oxford University9 Simulation  Loop over all 12 z positions  Generate beams (2) at 201 phi values  Loop over barrels 3 – 6  Intersect beam with barrel radius  Find appropriate detector and intersect with beam  Write accurate strip hit (and gun pars) to hit list  Write modules hit to scan list

9th October 2003James Loken – Oxford University10 HitToStrip  Read Scan list for modules hit  Read hit list for hit and gun pars  Generate 10K strips with Gaussian for r-phi and u/v-phi dets (beam 0.5 mrad x 20 mrad (?))  Add 20% (?) random background strips  Store as histogram  Save histograms (8) as root file  Repeat for each Scan (201 x 12)

9th October 2003James Loken – Oxford University11 Module Strip Data

9th October 2003James Loken – Oxford University12 StripToHit  Read Scan list for modules hit  Find Root file  Find Histogram for each module  Search histogram (in each half) for largest peak  Fit limited range around peak to Gaussian  Extract peak value as accurate hit  Write accurate strip hit (and gun pars) to hit list  Repeat for each module  Repeat for each Scan (201 x 12)

9th October 2003James Loken – Oxford University13 Fit to Strip Data

9th October 2003James Loken – Oxford University14 Reconstruction Equations

9th October 2003James Loken – Oxford University15 …getting lazy now…

9th October 2003James Loken – Oxford University16 …and now…

9th October 2003James Loken – Oxford University17 Reconstruction Equations

9th October 2003James Loken – Oxford University18 Some Results

9th October 2003James Loken – Oxford University19 …and with Banana Distortions

9th October 2003James Loken – Oxford University20 Goodness of Fits

9th October 2003James Loken – Oxford University21 X-ray Gun off centre

9th October 2003James Loken – Oxford University22 Recon Gun Shifted

9th October 2003James Loken – Oxford University23 Results from this for Barrel 3

9th October 2003James Loken – Oxford University24 …and Barrel 4

9th October 2003James Loken – Oxford University25 …and Barrel 5

9th October 2003James Loken – Oxford University26 …and Barrel 6

9th October 2003James Loken – Oxford University27 Conclusions (Observations)  A good start has been made  But much work to be done  If the Hardware works well, the Software can extract good results  It’s worrying to wait until 2005 to test it  But we should get some test data sooner  A good Calibration of the Gun is needed