J. I. Lamoureux

The CDF Plug Upgrade Electromagnetic Calorimeter: Test Beam Results

Abstract The CDF Plug Upgrade calorimeter, which fully exploits the tile–fiber technique, was tested at the Fermilab meson beamline. The calorimeter was exposed to positron, positively charged pion and positive muon beams with energies in the range of 5– 230 GeV . The energy resolution of the electromagnetic calorimeter to the positron beam is consistent with the design value of 16%/ E ⊕1% , where E is the energy in units of GeV and ⊕ represents sum in quadrature. The non-linearity for positrons is studied in an energy range of 11– 181 GeV . It is important to incorporate the response of the preshower detector, the first layer of the electromagnetic calorimeter which is readout separately, into that of the calorimeter to reduce the non-linearity to 1% or less. The energy scale is about 1.46 pC / GeV with HAMAMATSU R4125 operated typically at a gain of 2.5×10 4 . The response non-uniformity over the surface of a tower of the electromagnetic calorimeter is found to be about 2% with 57 GeV positrons. Studies of several detailed detector characteristics are also presented.

Intercalibration of the longitudinal segments of a calorimeter system

Three different methods of setting the hadronic energy scale of a longitudinally segmented calorimeter system are compared with each other. The merits of these methods have been studied with testbeam data from the CDF Plug Upgrade Calorimeter. It turns out that one of the (commonly used) calibration methods introduces a number of undesirable side effects, such as an increased hadronic signal nonlinearity and trigger biases resulting from the fact that the reconstructed energy of hadrons depends on the starting point of their showers. These problems can be avoided when a different calibration method is used. The results of this study are applied to determine the e/h values of the calorimeter and its segments.

A preshower detector for the CDF Plug Upgrade: test beam results

A preshower detector consisting of plastic scintillating plates with optical-fiber readout was tested at the Fermilab meson beamline. The detector was placed at a depth of about 1.5X0, followed by an electromagnetic and hadronic calorimeter, and exposed to positron, positively charged pion and positive muon beams with energies in the range of 5–227 GeV. Multianode phototubes, HAMAMATSU R5900-M16, were used for the photon readout. The efficiency for detecting two minimum ionizing particles with noise occupancy of <1% was 90–100% for gains of (1–4)×105. It was also found that by requiring an appropriately large signal in the preshower detector, the rate of charged pions depositing a large fraction of energy in the electromagnetic calorimeter could be reduced by a factor of 1.4–2.0 (1.4–2.8) while keeping 95% (90%) efficiency for positrons.