Relatore
Summary
In order to provide a precise, fast and reliable measurement of
the luminosity for
the e+e- collider of Frascati [DAFNE] during the crabbed waist
collision tests in the
2008 run a set of calorimetric detectors have been designed,
realized and put in
operation:
- a set of 2x2 half rings [back-to-back with respect to the
interaction point],
realized by 5 trapezoidal sectors [covering 30 degrees in phi
each] of sandwich
calorimeters [lead and scintillator read by WLS fibers]; these
detectors have been
optimized for detecting Bhabha events in the angular range 18 to
27 degrees.
- a couple of back-to-back radiative Bhabha proportional
counters, each made up of
four PbWO4 crystals, at very small angle [~1.7 mrad]. Those
counters, thanks to the
very high rate, are essential for real-time optimization of the
machine, even though
are sensitive to backgrounds and particles lost by the beams.
Those calorimeters have been carefully characterized and
calibrated at the Frascati
BTF facility with electron beams [linearity, resolution and
uniformity have been
measured]. Moreover, a full simulation of the setup has been
performed using GEANT,
in order to have a precise determination of the acceptance,
including the most
precise event generators for Bhabha processes and calculated
paths for Touscheck
backgrounds.
The data acquisition system, capable of several kHz of rate and
of measuring the dead
time with good accuracy, is based on the KLOE experiment DAQ and
acquirese both the
analog signal fed into charge ADC and the digitized signals fed
into TDC and scaler
for rate measurement and offline correction of the luminosity.
