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PIXEL SCANS

Explore advanced methods like pixel scans, mask scanning, and pedestal adjustment for precise data collection in scientific research. Learn about alignment data, intensity scanning, and more. For detailed information and further analysis, visit SpiderWiki.

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PIXEL SCANS

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  1. PIXEL SCANS

  2. Measuring Data • Measure last point before graphs cuts off at 1/10³. • For spread of data, imagine fitting curve and take point where it would cross X axis. • For larger spreads of data (see opposite), fit cubic polynomial.

  3. Mask Scanning • 9 x 9 Mask Scanned • 3 x 3 Aperture • 60% Intensity • 50μm step size • 1064nm Wavelength • 25Hz Firing Frequency • Continuous Firing • Scan Type: mpsAnalysis Threshold 149 • Scanned Between 50 and 350 units.

  4. Mask Scanning – 3D • Data Plotted In 3D for aesthetics. • Cut Off Point Measured By Eye, defined as when no hits are recorded with more than 1/10³ frequency.

  5. Mask Scanning: Histogram • Gaussian Fitted Ignoring Saturated Data Points. • Fitted by eye so may not be optimum

  6. Mask Scans Other Region • Another region was also scanned, 6mm down on sensor. • Prob statistic for green histogram is 0.1688. Mean = 186.7 ± 4.3. Sigma = 32.21 ± 4.11

  7. Pedestal Adjustment • Pedestals For each Pixel Subtracted And Data Replotted

  8. Pedestal Adjusted Histogram • Gaussian Again Fitted By Eye. • Histogram Does Not Include Saturated Pixels - 72 points.

  9. Pedestal Adjustment In Other Region

  10. Intensity • Automated Scans of Intensity For Several Pixels • 30-100% Alternating Steps of 2% and 3%. • Scanned between 0 and 500 units.

  11. Does Turning Laser Off and On Make A Difference? NO SIGNIFICANT DIFFERENCE

  12. Alignment Data • Scanned In Alternating 5 and 6 micron steps, over whole of Pixel (28,143). • 2 x 2 Aperture • 1 x 1 Mask over chosen pixel • 60% Intensity • (All other settings same as for Mask Scanning) • Coordinates arbitrary to allow ROOT plots.

  13. Alignment Plots Looks As Though Laser Is Out of Focus!!!

  14. Focused Alignment Scans • Scanned Along X Axis Through Centre of Four Pixels (Separate 1 x 1 Mask for each) • 2μm steps. • Pixel (29,143) best displayed twin peaks.

  15. Pixel (29,143) Alignment • Scanned along Y axis (through maximum point from earlier scan) to find Diode. • Then along X axis, through maximum Point from Y Axis Scan.

  16. END More data is at SpiderWiki http://hepilc01.pp.rl.ac.uk/spiderwiki

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