MAPMT H7546B anode current response study for ILC SiD muon system prototype

The proposed Si detector concept for the ILC has barrel and end cap muon systems. An SiD scintillator based muon system prototype has 256 strips and was constructed from extruded scintilator, WLS fibers, clear fibers, and multianode photomultiplier tubes (MAPMT). Six Hamamatsu H7546B were used. As a first step to understand strip output, the response of every anode to a given brightness of light and applied voltage must be measured. For the test, a custom made light source was used. Each MAPMT output was measured independently at constant (green) input light brightness and the same photocathode to anode voltage (800 V). The anode currents have a wide spread, for all tubes the maximum value is 5.23 times larger than the minimum value. The MAPMT cross talk was measured for one of the central inputs. The maximum cross talk value is about 4.9%. The average cross talk for the nearest four neighboring channels is 3.9%, for the farthest four is 1%. To assure the reproducibility and repeatability of the measurements, the double reference method was used.