The LabVIEW-Controlled Movable Collimator
The LabVIEW-Controlled Movable Collimator
S. Padalino, C. Freeman, H. Olliver, M. Olsen, B. Schwartz, S. Thompson
SUNY Geneseo
The LabVIEW-controlled moveable collimator was designed so that equipment could be repositioned inside the 2x2 chamber without having to go through the time consuming process of venting the chamber, moving the equipment by hand, and then pumping it out again. The ability to move the collimator in fine steps from side to side while under vacuum gives us the opportunity to perform many experiments that would be impossible otherwise.
In the plasma calorimeter project, we use this device to reposition the beam collimator and gold foil inside the chamber. Precise control of the collimator position is crucial in this project to ensure that the collimator and calorimeter foil are aligned properly. In order for the beam current on the calorimeter foil to be measured by the Rutherford-scattering technique, the collimator must be positioned so that all of the beam which makes it through the collimator also strikes the calorimeter foil of interest. Once one calorimeter foil is calibrated, the collimator and gold foil are moved to the other foil so that it can be calibrated.
The stepper motor which drives the collimator was taken from an old floppy disk drive. A computer running LabVIEW is used to control the stepper motor which in turn positions the collimator. A limit switch is mounted on one side of the track so that the position of the collimator can be accurately "zeroed".