Measuring a in the New experiment D. Hertzog / June 2004 n Plan that rates could be 7 x higher n...
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Transcript of Measuring a in the New experiment D. Hertzog / June 2004 n Plan that rates could be 7 x higher n...
Measuring a in the New experimentD. Hertzog / June 2004
Plan that rates could be 7 x higher Plan that new WFDs will have deep memory Plan that computer storage is infinite (well, large) Plan that processing is infinite (well, fast)
Q method: Energy vs time (integrated WFD samples)
T method: Traditional events above threshold, binned
Q and T imply different optimizations ….
Can we do both with one device and readout scheme?
Assert: Yes, we must try, but we may have to have a “favorite” and a “secondary” as details emerge
PbSciFi calorimeter features and faults
Features: Resolution good for this application
Linear over required range
Fast response with scint + PMTs for pileup rejection
Dense / compact (fits in tight space, minimizes side-entering electrons)
Faults: Mirrored ends imply position-dependent pulse shapes
14 cm high; gap is 18 cm (could use 16 at least)
No effective transverse segmentation for spatial pileup segmentation
Laser calibration system failed to give better than few tenths of a percent stability
The calorimeters we have are nearly ideal already for the Q method
Fibers run radially to 4 PMTs
Each tube gets its own WFD
Plot E vs time in 20 ns bins
You can even save all these records
You lose 7% of data’s statistical power compared to normal T method* (run 14% longer)
Refs: W. Morse g-2 Note #93
*J. Pretz g-2 Note #326
What calorimeter can handle the T method at 5-7 times the current rate?
Maintain 4 ns pulse separation by timing
Maintain density (to fit and avoid side e)
Segment transversely by about 20 fold
How to read it out?
What is it made of ?
Have considered so far
PbW crystals – $$, slow
SiW sandwich – $$$, R&D, slow?
Pb/Scint/Shaslak – long X0
Pb/SciFi rotated – remake blocks, how to read out?
?