Download presentation
Presentation is loading. Please wait.
Published byGraham Foulke Modified over 10 years ago
1
9th October 2003James Loken – Oxford University1 SCT X-ray Alignment Software A First Look
2
9th October 2003James Loken – Oxford University2 Complete Tomograph -set-up-
3
9th October 2003James Loken – Oxford University3
4
9th October 2003James Loken – Oxford University4
5
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’’
6
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
7
9th October 2003James Loken – Oxford University7 Detector Orientation
8
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)
9
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
10
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)
11
9th October 2003James Loken – Oxford University11 Module Strip Data
12
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)
13
9th October 2003James Loken – Oxford University13 Fit to Strip Data
14
9th October 2003James Loken – Oxford University14 Reconstruction Equations
15
9th October 2003James Loken – Oxford University15 …getting lazy now…
16
9th October 2003James Loken – Oxford University16 …and now…
17
9th October 2003James Loken – Oxford University17 Reconstruction Equations
18
9th October 2003James Loken – Oxford University18 Some Results
19
9th October 2003James Loken – Oxford University19 …and with Banana Distortions
20
9th October 2003James Loken – Oxford University20 Goodness of Fits
21
9th October 2003James Loken – Oxford University21 X-ray Gun off centre
22
9th October 2003James Loken – Oxford University22 Recon Gun Shifted
23
9th October 2003James Loken – Oxford University23 Results from this for Barrel 3
24
9th October 2003James Loken – Oxford University24 …and Barrel 4
25
9th October 2003James Loken – Oxford University25 …and Barrel 5
26
9th October 2003James Loken – Oxford University26 …and Barrel 6
27
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
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.