1.) Readout:
LVDS cross talk problems forced a redesion of Helix chip driver
boards. It seems the ground plane was not enough to
isolate the 40 MHz LVDS pulses from other traces on the
same board. The cross talk was reduced by separating the
LVDS signal board from the HELIX board. A ~30 cm ribbon
cable is used to run the LVDS signals to the HELIX card
instead of incorporating the HELIX card onto a single board.
2.) Detector
Installing new 2-D charge collector into 1st prototype detector.
The new charge collector design eliminates fragile wire
bonds.
4.) Detector rotator apparatus
All rotation hardware is in place and working together. Software
routines have been written to radially move each GEM detector
independently to its limit switch.
A software routine to rotate detectors is next.
Model 80111 Omnidirectional Lever
is being considered as rad hard microswitch to count teeth of
ring gear as it rotates. The motor encoders are NOT
expected to survive the high radiation environment.
The above lever doesn't indicate direction of rotation however so
we are still looking for something better as well as a
rotator limit switch.