I selected 634 runs for calibration from the Run 9 production, processing over 300M events. The runs are listed in this list, with their field designation.

The MIP peak for each tower was calculated. 4663 towers had MIP peaks found. 38 were marked as bad. 99 were marked as MIPless. The MIP peak fits are here.

The electrons were selected using the following cuts:

• |vertex Z | < 60 cm
• vertex ranking > 0
• track projection enters and exits same tower
• tower status = 1
• 1.5 < track p < 10.0 GeV/c
• tower adc - pedestal > 2.5 * pedestal RMS
• Scaled dR from center < 0.02
• 3.5 < dE/dx < 5.0
• No other tracks in 3x3 cluster
• No energy in cluster > 0.5 central energy
• Track can only point to HT trigger tower if a non-HT trigger fired in the event

Fig. 1: Here is a comparison of all electrons from RFF (blue) and FF (red):

The RFF fit mean comes to 0.965 +/- 0.001. The FF fit mean comes to 0.957 +/- 0.001. The total fit is 0.957 +/- 0.0004.

Fig. 2 Comparison of electron (red) positron (blue):

Positron fit results: 0.951 +/- 0.001. Electron fit results: 0.971 +/- 0.001

Calibration was calculated using MIPs for relative calibration and absolute calibration done for eta slices by crate (30 crates, 20 eta slices per crate).

The outer ring on each side was calibrated using the entire ring.

2 towers were marked bad: 2439 2459 due to a peculiar E/p compared to the other in their crate slice. It is suggested this is due to bad bases.

Fig 3 Crate Slice E/p correction to MIPs (eta on x axis, phi on y axis):

New GEANT correction

A new geant correction was calculated using new simulation studies done by Mike Betancourt. The energy and pseudorapidity dependence of the correction was studied, and the energy dependence is small over the range of the calibration electron energies.

A PDF of the new corrections are here.

Is it statistical?

From this plot, it can be seen that most of the rings have a nonstatistical distribution of E/p values in the slices. The actual E/p values for each ring (for arbitrary slice value) can be seen here.

Comparison to previous years

Fig 4 Eta/phi of (data calibration)/(ideal calibration)

Fig 5 Eta ring average of (data calibration)/(ideal calibration)

Issues:

• FF vs RFF (partially examined)
• positive vs negative (partially examinced)
• eta/phi dependence of geant correction, direction in eta/phi
• dR dependence of calibration
• comparison to previous year