DRAFT

Relation of TPC and Magnet coordinates

The center of the TPC coordinate frame is located at (-2.76 mm, -0.82 mm, -1.92 mm) in the Magnet coordinate frame. The B field was pointing West along the Magnet z axis in the Summer 2000 run. For this condition the B unit vector in the TPC frame is:

Coordinate diagrams shown below:

Note:

· The angle shown in the xy plane is referenced with the East pad plane. There is currently a large uncertainty in this angle, but it can be resolved with access to the survey files.

· The West pad plane is rotated -0.43 mrad in phi with respect to the East pad plane. See: http://www.rhic.bnl.gov/~wieman/tpcrot/endcaprotation.htm

· DZ is uncertain by ~0.5 mm. The TPC was measured twice once standing alone in the assembly hall and once after it was installed in the magnet. The TPC measured 0.51 mm longer in the second survey.

· The coordinate information in this note is based on the Brookhaven Survey and Alignment Group report:

Job name: PRE_TPC Date:02/22/99 14:00

Coordinate system 2 11_99 LHR

Job ID : 05/19/98 FXK