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Timing Study of VSVX Occupancy

Timing Study of VSVX Occupancy. Yurii Maravin FNAL. Data samples. 10 special runs taken 01-10-03 VSVX threshold set to max (~7 p.e.) Integration window shifted around the default value in the range of –93.3 ns to +113.0 ns More details: CFT_Log #168556. Data Samples. Analyze the data.

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Timing Study of VSVX Occupancy

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  1. Timing Study of VSVX Occupancy Yurii Maravin FNAL

  2. Data samples • 10 special runs taken 01-10-03 • VSVX threshold set to max (~7 p.e.) • Integration window shifted around the default value in the range of –93.3 ns to +113.0 ns • More details: CFT_Log #168556

  3. Data Samples

  4. Analyze the data • Develop a code that creates root-tuple with VSVX hits information regardless on SVX data • Remove offline threshold (20 counts) • Implement root macros to analyze VSVX information: • Analyze VSVX occupancy (per layer, per trigger sector etc) • Search for missing SVX info (VSVX fired, SVX missing)

  5. VSVX Occupancy Default Layer A C B maximal vsvx threshold (7 p.e.) D E F H G

  6. VSVX Occupancy (cont) • Current position of the integration window is not optimal – VSVX occupancy is still going up if delayed • Can increase efficiency by another 40-60% by delaying ~50 ns: • VSVX efficiency per SVX hit: • Default: (53.7 +/- 3.4) % • +56.5 ns : (81.0 +/- 4.3) % • Interesting to see VSVX efficiency per SVX hits for 1% threshold.

  7. Occupancy per trigger sector • In the next 9 slides, VSVX occupancy histograms are plotted as a function of a trigger sector • Please note that the distributions are not flat for the default settings. It is probably caused by the timing inefficiency

  8. Shift –93.3 ns

  9. Shift –56.5 ns

  10. Shift –18.3 ns

  11. Shift 0 ns (Default)

  12. Shift +18.8 ns

  13. Shift +37.7 ns

  14. Shift +56.5 ns

  15. Shift +75.3 ns

  16. Shift +112.96 ns

  17. VSVX Occupancy for layer H -96 ns -60 ns -24 ns Default +18 ns +36 ns +54 ns +72 ns +108 ns

  18. VSVX Occupancy SS# 1 SS# 2 SS# 3 SS# 4 SS# 5 Default maximal vsvx threshold (7 p.e.)

  19. “Quality” of VSVX hits • We get much more VSVX hits if we delay the integration window • What about ADC information?

  20. ADC distributions • Plot ADC values for fibers where VSVX fired: • Indication of • fibers with low ADC counts • invalid SVX value (SVX = 255) • missing SVX information (SVX=0)

  21. VSVX = 1 and SVX = 0 (no counts) Related to hot VSVX channels? Compare geographical distributions of hits for all data and these with ADC != 0

  22. –93.3 ns data All hits ADC != 0 Total hits with ADC = 0: 154,507. 63,137 of which (41%) of which are under ‘hot’ VSVX regions. Hot channels are not hot all the time!

  23. How many hits do not have SVX info? Occupancy Hits with no ADC

  24. Summary • VSVX occupancy results suggest delaying the edge of the integration window • Non flat VSVX hits distribution indicates timing inefficiency • VSVX hits distributions looks flat for Dt > 36 ns • However, a lot of VSVX hits with no ADC information!

  25. Summary • Indication of hot VSVX channels, indication of missing SVX information • Can provide position of hot VSVX channels

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