1. Dual-Readout Calorimeter: DREAM
Richard Wigmans, Nural Akchurin,
Heejong Kim, Hans Paar, John Hauptman
CERN H2 beam – summer 2003

2. “Dual Readout” - Cerenkov+Scintillation in same event
Fluctuations in pi-zero content of hadronic showers limits energy resolution, introduces a constant term, and results in a non-linear calorimeter response
Cerenkov light is largely generated by electrons from photons from pi-zeros, and therefore measures the pi-zero content event-by-event
Scintillation light measures all charged tracks

3. Basic unit: 4mm x 4mm Cu tube

4. Beam view of module: hexagons define geometric channels
Module is 2 meters deep in beam direction

5. Rear of module: Cerenkov and Scintillation fibers go to separate R725 Hamamatsu PMTs
Bright light shining through 2 meters of Cu

6. H2 Beam at CERN: not quite to scale

7. Pre-Shower Detector: clean IDs

8. Cerenkov and Scintillation pulse height distributions

9. Cerenkov vs. Scintillation

10. EM shower fraction distribution

11. (Q+S)/E

12. S corrected by Cerenkov-measured EM fraction

13. Before & After EM fraction correction

14. Pion Energy Resolution

15. Distributions of “center-of-light”

16. Before & After Cerenkov-measured EM fraction

17. Energy resolution of “interaction jets”