Prototype Mechanical / optical considerations 1.Current LED system performance 2.New APD / Fiber /Strong Back integration scheme

LED Calibration and Monitoring System

Optical router for 12 LED pulses for the 12 Modules in a strip module

Module gain monitoring signal compared to cosmic ray peak

Recent Improvements: Last measurement of LED signal from the tower with 0.5 mm fibers corresponds to ~4 GeV electrons For the test beam prototype, increase diameter of secondary fibers up to 0.75 mm and use a jacketed fibers to increase optical isolation. Estimated improvement ~2 times. New LED board up a signal ~2 times. (Hans Schedule ??) Goal is to have LED system capable of ~ 16 GeV pulses

New APD/Fiber/Strong Back integration scheme.

Old APD/Fiber/Strong Back integration scheme.

Three proposed variants of new APD/Fiber integration scheme. Deeper cavity variant adopted Leaf spring

New integration Scheme Adopted for test beam

New integration Scheme Adopted for test beam