1. Cosmic Ray Test Stand with Scintillating Cells for Digital Hadron Calorimeter As of 9am 05/28/2003

2. Status Determined single electron peak - two checks to justify calling it a single photoelectron peak –as I reduce light average drops but distance from pedestal remains same –comparison of Oscilloscpe captures Also determined that the cause of bad channels in previous data sets was due to QDC

3. 7.00V 8.25V 9.00V 9.75V Used 3 layers of paper to attenuate signal and changed voltage Peak remains at same position as voltage is decreased

4. Sample with gate with 2 layers of filter paper Comparison of Oscilloscpe captures

5. Sample with gate with 3 layers of filter paper

6. Summary These two checks lead me to think that this IS a single photo-electron peak Set pulse generator to 22.3ns pulse width, 9.75V and 3 layers of white paper as attenuator between LED and PMT photocathode For Channel 6: Pedestal=76, S.P.E.Peak =100, MIP peak=439 Therefore we have a light yield of 15 P.E. Also, using upper 16 channels of QDC I can get collect data from all 14 cells (the lower 16 channels only had 13 working channels)

7. Light yields for 14 channels based on ESTIMATES of single electron and MIP peaks.

8. Next Steps Collect pedestal only data for PMT connected to upper 16 channels Get better determination of single electron and MIP peaks (using PAW after subtracting pedestal) Refine calculation of Light Yield Subtract variations in channels to get properties of cells Would like to collect one more long weekend of data with absorber