High resolution measurements of lepton beam transverse distributions with the LEP wire scanners

Abstract

A large number of improvements were canied-out on the LEP Wire-Scanners in preparation for the 1992 running period.They include modifications of the monitors mechanics to decrease the vibrations and the heating of the wire by the beam generated electromagnetic fields, improvements of the detector chain and a software re-organization at the various levels for better noise rejection, improved user interface and "off-line" data analysis capabilities. It is now also possible to acquire the profiles of each of the sixteen circulating bunches, electrons and positrons, during the same sweep. As a consequence of these actions the quality of the collected data is much improved. The results are presented and discussed.

Improved CLIC performances using the beam response for correcting alignment errors

“…1 corresponds to coupling to the beam electric field and depends on the wire length and on the RF spectrum of the bunch. These hypotheses agreed with observations made where the wire temperature changed at constant current when the bunch length was changed [3]. The beam current limit could then be increased to circulating beams of 3 mA at a wire speed of 0.5 m/s.…”

“…The original problems and the evolution of the LEP wire scanners are described in Ref. [2,3]. The original forks were part of a common design for LEP and SPS.…”

“…These levels were thought to result from magnetic coupling of the fork/wire loop to the wakefield in the tank for the first case, and to the magnetic field generated by the beam for the other case. This coupling was strongly reduced by modifying the fork construction by breaking a parasitic loop [3]: see "old#2" fork in Table 1. Temperature levels of 230°/mA and 530°/mA were then measured.…”

Electron Beam Diagnostics for TTF II

“…Wire-scanners A modified version of the CERN-LEP wire-scanner [8] will also be used for transverse beam profile monitoring. Mounted under 45 with respect to the horizontal plane and using a Vlike wire schema allows x and y profile measurements with a single scanner.…”