Transcript slide

Dual-Readout Calorimeter:
DREAM
Richard Wigmans, Nural Akchurin,
Heejong Kim, Hans Paar, John Hauptman
CERN H2 beam – summer 2003
“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
Basic unit: 4mm x 4mm Cu tube
Beam view of module:
hexagons define geometric channels
Module is 2 meters deep in
beam direction
Rear of module: Cerenkov and
Scintillation fibers go to separate
R725 Hamamatsu PMTs
Bright light shining
through 2 meters of Cu
H2 Beam at CERN: not quite to scale
Pre-Shower Detector: clean IDs
Cerenkov and Scintillation pulse
height distributions
Cerenkov vs. Scintillation
EM shower fraction distribution
(Q+S)/E
S corrected by Cerenkov-measured
EM fraction
Before & After EM fraction correction
Pion Energy Resolution
Distributions of “center-of-light”
Before & After Cerenkov-measured
EM fraction
Energy resolution of “interaction jets”