page_title: CPLEAR experiment
section_title: Layout of the detector
hierarchical_section_title: CPLEAR experiment / The experiment / Layout of the detector
caption_attribution_description: English: The CPLEAR detector
context_page_description: The CPLEAR experiment used the antiproton beam of the LEAR facility - Low-Energy Antiproton Ring which operated at CERN from 1982 to 1996 - to produce neutral kaons through proton-antiproton annihilation in order to study CP, T and CPT violation in the neutral kaon system.
context_section_description: The detector had to fulfill the specific requirements of the experiment and thus had to be able to: 
  do an efficient kaon identification
  select the annihilation channels mentioned in Facility description among the very large number of multi-pions annihilation channels
  distinguish between the different neutral-kaon decay channels
  measure the decay proper time
  acquire a large number of statistics, and for this, it had to have both a high rate capability and a large geometrical coverage
  Cylindrical tracking detectors together with a solenoid field were used to determine the charge signs, momenta and positions of the charged particles. They were followed by the particle identification detector (PID) whose role was to identify the charged kaon. It was compounded by a Cherenkov detector, which carried out the kaon-pion separation; and scintillators, measuring the energy loss and the time of flight of the charged particles. It was also used for the electron-pion separation. The detection of photons produced in π⁰ decays was performed by ECAL, an outermost lead/gas sampling calorimeter, complementary to the PID by separating pions and electrons at higher momenta. Finally, hardwired processors (HWK) were used to analyze and select the events in a few microseconds, deleting the unwanted ones, by providing a full event reconstruction with sufficient precision.
caption: The CPLEAR detector
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