Optical monitoring system for ECAL detector delivered
First two pieces of the optical monitoring system for the ECAL detector, experiment HADES, were delivered at the end of May 2017. Optical monitoring system will enable regular control of every single module of the ECAL detector by sending short light pulses directly into the lead glass. These pulses will be read-out by photomultiplier and the output electric signal will be identical to the signals invoked by the real particles registered in the detector. Each device of the optical monitoring system is composed of a blue laser LED with protecting electronic circuit, dedicated optical diffuser and microlens array, and a pack of 196 optical fibers optimized for blue light. Uniqueness of the device is in the homogeneity of the light distribution among the fibers – differences in the light amount are within ±10% for most of the fibers, what is a very good result. The two pieces of the optical monitoring system will be now thoroughly tested in the detector labs of NPI. The remaining three pieces of the system will be delivered at the end of June 2017. Optical monitoring system was purchased from the budged of the EU project “Facility for Antiproton and Ion Research - participation of the Czech Republic – OP”, registration number CZ.02.1.01/0.0/0.0/16_013/0001677.