Precision synchrotron radiation detectors

Precision detectors for measuring synchrotron radiation beam positions have been designed and installed as part of 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, thereby contributing less than 5 MeV to the error in the measurement of 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. Detectors of synchrotron radiation using the charge developed by the ejection of Compton-recoil electrons from an array of fine wires are being developed. >