Okay. We are getting near the end.
The attached file is the Excel file for the optical survey of the
wire chambers with the sub-detector closed. Note that there are two
worksheets in the Excel file. The first has the data and the second
has Karen's summary. Note I used the data but thereafter followed a
somewhat different path. Karen and I have discussed what I did and I
think we agree that it is okay.
The optical survey can not see the targets on the top or bottom of
the WC's when it is closed so uses targets on the sub-detector frame
and on the ends of the wire chambers.
Karen analyses all the data and gets a translation along Z and
shifts left/right and up/down for each sector as well as rotations
but these are largely based on the frame data and the coupling to the
chamber while rigid is not so obvious and particularly the point of
the rotations is not obvious to me. Also she refers to a pitch and
roll of the idealised chamber which is taken out if one starts with
the sim data rather than the ideal positions. So I deviated at this
point.
Using Karen's data I selected a target on the upstream end of the
assembled WC in each sector (LCUMOM and RCUMIM). I then translated
the sim data for the WC as a whole to coincide with the survey value
at this point. Then I chose a target at the downstream end in each
sector ( LCDMOM and RCDMOM) and rotated about Y and X centred at the
upstream point so that the down stream targets agreed. Finally I
chose a third target on the chamber LCUMOB and RCUIOB and rotated
about the chamber axis to put these on. Then I determine the chamber
centres and normals after all these rotations which result in the
final values as in WC_chamber_parameters.
The final values I obtained are for the left sector:
- translate to LCUMOM and rotate the centres for the three chambers
by 0.12 deg about the verical, by -0.07 deg about the chamber Z axis,
and then by -0.1 deg about the chamber X axis.
- apply the same rotations to the chamber normals
For the right sector the centre of rotation is RCUMIM and the angles
are -0.025, 0.011, and -0.14 degrees.
The file WC_wire_parameters uses the ideal positions for the wires
relative to the centres of the super-layer in each chamber and the
results from the CMM analysis which is a small correction.
Cheers,
Douglas
26-415
M.I.T. Tel:
+1 (617) 258-7199
77 Massachusetts Avenue Fax: +1
(617) 258-5440
Cambridge, MA 02139, USA E-mail:
hasell@mit.edu
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