Minutes of CDC subgroup Meeting ***(monthly)
Minutes of JLC CDC Subgroup Meetings
Date and Place
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October 21, 1995 at KEK (Saturday)
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Attendants:
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K.Fujii,Y.Kurihara, N.Khalatyan, S.Sudou
- Wire Sag Calculation
Simple linear formula works well:
Al wire sags
------> Good at the 1-st iteration and
improves with the number of iterations.
W wire sags
------> Left-right asymmetry could not be reproduced with
the nominal HV values and the nominal original
positions.
Observed asymmetry <--> about 30 V shift in the
H.V. on grid wires.
Discussions
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i) H.V. setting
Found one cable (H.V.) to a field wire broken.
-----> could have been the source of asymmetry.
ii) How accuratly should we predict the sags?
50 micron might be already good enough.
---- > x-t, drift field...
iii) Sense wire electrostatic sags are harder to predict since they are
2-nd order effects (Kurihara).
iv) Sense wire sag about 2-x Field wire sag.
if E-field is the same since wire tensions are a factor
of 2 different
v) Even if the sense wire sags are higher-order effects, if
they are large, there must be enough source of asymmetry in
wires other than the sense wire
---- > Effects of other cells
(broken H.V. cables, machining errors of wire holes)
vi) Need to study stability (Kurihara).
- Wire Tension Measurements
New magnets
---- > about 3 kG at front faces.
---- > about 30 G at the center of the chamber.
Measured several wires
Al- wires seem to start saturating.
W - wires difficult but feasible to measure.
- Cosmic Ray Test.
Flash ADC
Readout
Noise problem -- > Follow the B-factory design:
--- > O.K.
Estimate signal size.
- Movement
----- > Ask a company
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