The hodoscopes consisted of two sets of plastic scintillator arrays (H1 and H2) located directly behind each of the arm's Cerenkov arrays. The hodoscope arrays provided a greater segmentation than could be obtained in the Cerenkov systems, thereby allowed for narrower search regions in the process of finding the drift chamber hits used in the track reconstruction algorithms. The hodoscope arrays also added the capability for the detection of charged particles, primarily pions and protons, in the spectrometer. This capability allowed for the evaluation of the hadron detection rates, which were used both in diagnostic investigations into the spectrometer's performance and in providing estimates of the hadron rejection power provided by the Cerenkov systems.
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