1. Xtal Calorimeter with Fiber Readout work by diploma student  Ralph Dollan (HU) Achim Stahl DESY Zeuthen 10.Oct.2003 LumiCal BeamCal

2. Detector Concept segments of heavy crystals individual fiber readout for every crystal segment Expectations: excellent energy resolution excellent timing reasonable segmentation small Molière radius (?)

3. Test Setup Cosmic Telescope Alternative: Ru-Source

4. Calibration of PMTs PMT LED

5. Lightyield Measure Lightyield with plastic scintillator Compare fiber readout vs. direct readout

6. Lightyield fiber readout direct readout ~ 25 %

7. Cross Talk How much light do fibers see from other crystals fiber painted with black paint

8. Cross Talk cosmics ? but ….

9. Outlook  complete cross talk studies  test fiber readout for Čerenkov radiator  investigate heavy crystals  try APD readout  build larger array but..… Ralph will finish end of this year no further man-power available

10. PMT - Calibration