Beam profile vs time

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Beam profile vs time

• Analyzed Vx vs Vy distributions vs time for
• Run 72 (132602 2825)
• Run 73 (133610 133730)
• Run 74 (4312 4421)
• Binned distributions with the same Vernier scan
  location
• No Z vertex cuts
• Cut on Vr lt 2

Rosi Reed rjreed_at_ucdavis.edu 6/9/08
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Gaussian Multiplication

• Beam is gaussian in shape
• Distribution of collisions in xy space is equal
  to the beam distributions multiplied by each
  other
• Also gaussian in shape

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• Assuming the beams have the same width

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Vernier Scan
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Beam profile vs time Summary
Beam-Beam Events
Calculated from Vx vs Vy distributions
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(No Transcript)
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Plots with less than 12 data points not included
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Beam Sigmas calculated from formula on pg 3
Error reflect statistical error only
Sigma X 1.75 mm /- .20 Sigma Y 2.40 mm /-
.15
If our assumptions are correct, these
distributions should be flat
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Horizontal Vernier Scan
Slope should be /- 0.5 if our assumptions were
correct
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Vertical Vernier Scan
Slope should be /- 0.5 if our assumptions were
correct
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Some comments

• I noticed that as the good event rate went down,
  the ratio of good events to beam pipe events went
  down
• I would like to quantify this next week
• No events with a vertex in Run 72 between
  132329 and 2602
• I have not looked at what happened in Run 73
  between 1330 and 35
• We conclude that the widths of the beams are
• Sigma X 1.75 mm /- .20
• Sigma Y 2.40 mm /- .15