1. SLAC, HiRes T-461: “FLASH” part 1 Justin Findlay

2. Apparatus

3. Data: ntuple Run Event Type: event type N e - : number of electrons n: blind north PMT N: signal north PMT s: blind south PMT S: signal south PMT Pressure Temperature hV: high voltage Flow: gas flow Mixture: gas mixture Quality: event quality NL: signal PMTs’ SL, nearest LED event Np: each PMT’s Np, nearest pedestal sp Sp

4. Data: runs

5. Cuts: high voltage beforeafter

6. Cuts: LED before

7. Cuts: LED after S bar LED N bar LED

8. Data Reconstruction Subtract pedestal Correct PMT gain wander Extrapolate from LED events to all events Convert blind PMT gain to signal PMT gain Subtract background measured by blind PMT

9. Cuts: signal PMT correlation Blue: non-ethylene data Black: ethylene data

10. Cuts: N e - per  linearity, air

11. Cuts: N e - per  linearity, N 2

12. Yield

13. Yield: function Y: yield C: constant  0 ∙ and p’: represent wavelength specific constants p: pressure

14. Yield: fit, air

15. Yield: fit, N 2

16. Yield Still need to incorporate errors propagated  2 / N df too large for result to be reliable Try for the principal lines

17. Systematic Error Account for systematic biases and failings - PMT Gains - Pedestals / Data Acquisition System - Beam Monitor - Temperature - Pressure

18. The End