A precision synchrotron radiation detector using phosphorescent screens

A precision detector to measure synchrotron radiation beam positions is described. It has been designed and installed as part of the beam energy spectrometers at the Stanford Linear Collider (SLC). The distance between pairs of synchrotron radiation beams is measured absolutely to better than 28 mu m on a pulse-to-pulse basis. This contributes less than 5 MeV to the error in measuring SLC beam energies (approximately 50 GeV). A system of high-resolution video cameras viewing precisely aligned fiducial wire arrays overlaying phosphorescent screens has achieved this accuracy.<
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