FDC Backgrounds

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Detector Configuration

• Double-Hit Resolution: 250 ns
• Threshold: 1 keV
• Strip Threshold: 5 mV
• Maximum Number of Hits: 100

Items for Discussion

• These rates seem incredibly high.
• Is the maximum number of hits coded into the simulation sufficient for the FDC? If it is applied at the event level, 100 hits is probably not enough.
• How relevant is the increased background as a function of downstream position of the package?
  • Does this need to be considered when optimizing package placement?
  • Do/Should the dead regions for each package vary in size depending on downstream location?

Plots

A plot of the rate as a function of anode wire number for the most dowstream anode plane (blue), the most upstream anode plane (red), and the average rate (black).

A plot of the rate as a function of cathode strip number for the most dowstream cathode plane (blue), the most upstream cathode plane (red), and the average rate (black).

A plot of the rate within 5 cm of the beam axis as a function of the plane number if the FDC. Planes for which N%3 == 2 are anodes, all other planes are cathodes. The notable increase in rate for the downstream chambers could be due to opening of charged particles in the relatively weaker field.

A double-log plot of the energy of all hits in the FDC. The spectrum cuts off at 1 keV due to the GEANT threshold.