Presentation on theme: "Alignment systems for GlueX GlueX Collaboration Meeting Bloomington, Indiana May 20-22, 2004 Courtesy of Dimos Sampsonidis, Aristotle University of Thessaloniki."— Presentation transcript:
Alignment systems for GlueX GlueX Collaboration Meeting Bloomington, Indiana May 20-22, 2004 Courtesy of Dimos Sampsonidis, Aristotle University of Thessaloniki Presented by Zisis Papandreou, University of Regina
NIKHEF Web Page Pattern used to measure x- and y-axis, size for z-axis Range of several cm with accuracy less than 1 m
Three point relative alignment measurement systems (RASNIK) with accuracy ± 1μm. Y X The main element used in chamber alignment and QA/QC during chamber construction The infrastructure - RASNIK systems Original system used a bright dot Lens adapted to layout CCD camera 400000 pixels pixel size 7x7μm 2 Mask and light source
Performance, in terms of Image Position on Sensor: x = 0.05 µm y = 0.05 µm scale = 2 x 10 -5 RotZ = 20 µrad Coded Mask Y X RASNIK specs Alignment information from image pattern recognition Infrared LED
Online Quality Assurance Temperature variation Effect on RASNIK monitoring for tube layer position (z coordinate) Temperature variation at Stiffback Temperature variation at Rasnik Tower The height of the clean room is limited (2,65 m). The stiffback is heated from the lights while it is suspended. 6 m shift of stiffback visible!
What’s required RasNik components: camera, mask, lens PC with FrameGrabber: data translation Rasmux: a custom multiplexer –For use with camera and mask –Suitable cables Software: free from NIKHEF AUTH will contact NIKHEF for a system or could participate in system development
BCAM: another option Boston CCD Angle Monitor ATLAS forward muon chambers Camera electronics is radiation resistant 10 mrad field view At 16 m 3rad accuracy Minimum effect of turbulence on resolution