| This board has a Hamamatsu LVR-6050CS-SMP1 SiPM in the middle, 6x6mm sensitive area. |  | 
| This frame mounts loosely on the (inner) 4 big holes, and is aligned with pins closest to the SiPM. 
The fibers are 60mils = 1.524mm. So 4x4 fibers don't fit, but a 4x3 hex 
pattern measures 5.48x5.33 mm.
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