1. M. Ellis - 11th February 2004 Sci Fi Cosmic Light Yield 2 views 3 views

2. M. Ellis - 11th February 2004 Sci Fi Cosmic Light Yield  At Abingdon, reported a light yield of approximately 4-5 PE.  Since then, investigations of more recent data taken with trigger timing information indicate that this was an underestimate.  VLPC readout is sensitive to the timing of the trigger with respect to the DAQ. Cutting on this time shows a strong effect on the amount of light recorded.

3. M. Ellis - 11th February 2004 Pedestal Run – All ADCs  Data taken without tracker.  Same code used to subtract pedestals and common mode noise as for all other plots in this talk

4. M. Ellis - 11th February 2004 ADC for all events – cosmics  5  above pedestal = 16 ADC  Trigger wrt DAQ times range between 170 and 210 ns  Times divided into 10 bins and the mean of all ADCs above 16 determined for each bin in time  Plots on next pages show ADC distribution in bins of time…

5. M. Ellis - 11th February 2004 Bin 1: 170 –174 ns Overflow Bin

6. M. Ellis - 11th February 2004 Bin 5: 186 – 190 ns Overflow Bin

7. M. Ellis - 11th February 2004 Bin 9: 202 – 206 ns Overflow Bin

8. M. Ellis - 11th February 2004 Mean Light Yield vs Timing  For 170 – 190 ns, mean light yield is as reported at Abingdon: 4 – 5 PE.  For 200 – 210 ns, light yield is 10 – 11 PE, as expected from the extrapolation from D0.  Once tracking is ready, light yield can be confirmed by looking at hits in tracks.

9. M. Ellis - 11th February 2004 Summary  Initial estimate of low light yield was probably due to a timing problem in the DAQ setup – this will be investigated when the Sci Fi group meets at Fermilab in 2 nd week of March.  For the data without timing information, tracking should allow us to reproduce the 10- 11 PE determination. Progress has been made on the understanding of the decoding of the cosmic setup and Makoto and I will be working intensively on the analysis in Japan during the last two weeks of February.