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?

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