For clarity, I show the rear side of the positioning system here. The optical mount positioned on the y linear motor. The mass of the optical mount is less than 500g and the centre-of-mass is about 20mm away from the motor.
The experiment "Livermore Inset" which has been used in November, and will be used again in March, has now been mounted in the chamber. The vacuum is spectacular without the inset (7x10-10mbar without baking), and 10-7 mbar with the inset. The experiment is centered in the left-hand CF360 double-cross. On the pic: Mike Bogan, Sebastien Boutet, and Urs Rohner from Livermore.