The UI group has built two of the scintillator arrays placed at the
end of the FOCUS spectrometer which is used to identify muons.
- The two UI arrays are labeled MH1 and MH2.
- The MH1 array consists of 84 vertical and 126 horizontal counters.
- The MH2 array consists of 52 vertical and 78 horizontal counters.
- The MH3 array built by our colleagues at University of Puerto Rico
consist of 54 counters at + 45 degrees and 54 counters at - 45 degrees.
- Muon are shielded by about 15 absorption lengths of iron which
absorb all charged particles from charm decay but muons.
- The use of scintillation counters allows for very crisp (1 Rf bucket)
timing.
- Fine granularity is used in order to uniquely match tracks to muon hits
to the extent allowed by multiple Coulomb scattering
- Here is a schematic of the MH1 array
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