The ALICE ITS Alignment Monitoring System, ITSAMS, is a simple geometrical optics system using off-the-shelf PC CCD cameras and USB communication protocols. The system consists of, a computer to monitor the signals, eight multi-mode fibers for signal transport, a CAT5 USB 1.1 bridge, motor control systems, four spherical mirrors each with a piezoelectric motor for remote angular adjustment, and four Active Sensors. Each Active Sensor contains a USB CCD camera, a 0.8 mW laser diode light source, a fiber optic collimator, an optical USB signal extender, an electronics driver board, and two piezoelectric motors for remote adjustment. The laser diode produces a light source which is then collimated into a beam and projected onto a spherical mirror mounted on the ITS SSD cone. The spherical mirror, having a focal point located on the CCD imager, then focuses the beam back onto the Active Sensor’s CCD array. A movement of either the mirror or the Active Sensor causes the beam spot on the CCD array to move. This automatically produces a resolution of relative movement between the two pieces on the order of the CCD pixel size. Using the geometry of the placement of the four mirrors and Active Sensor pairs, it is possible to reconstruct the motion of the ITS, as a rigid body, in 3-dimensional space to micron level accuracy. For a more in-depth description, please read our draft ALICE Note .doc file.  

      A modified set of drivers which will support multiple Panasonic GP-KR651US ( Divio NW802 chip set) can be found here. This Windows driver will suppor multiple cameras by making small modifications in the inf and related files.