Computer-Automated Linac Diagnostics and Data Acquisition
Computer interactive diagnostics have been developed and tested for measuring RF Linac electron beam position and emittance. Electron beam position is measured with ferrite-loaded stripline monitors. The measured signals are processed by an APPLE-II computer, displayed and updated (at the Linac repetition rate) on a monitor. Data to determine emittance is collected by measuring electron beam spot size (using the wire scanner technique) as the focal strength of a quadrupole triplet is adjusted around the focus at the scanner. The emittance is calculated by the APPLE-II making a hyperbolic curve fit to these data.
Beam measurements on Argonne linac for collider injector design
The 20 MeV electron linac at Argonne produces 5 × 1010 electrons in a single bunch. This amount of charge per bunch is required for the proposed single pass collider at SLAC. For this reason the characteristics of the beam from this machine are of interest. The longitudinal charge distribution has been measured by a new technique. The technique is a variation on the deduction of bunch shape from a spectrum measurement. Under favorable conditions a resolution of about 1° of phase is possible, which is considerably better than can be achieved with streak cameras. The bunch length at 4.5 × 1010e− per bunch was measured to be 15° FWHM. The transverse emittance has also been measured using standard techniques. The emittance is 16 mm-mrad at 17. 2 MeV.
Beam Position Measurement for Proton-Antiproton Operation in the SPS
New beam monitors and receivers have been constructed for the position measurements of the colliding pp beams in the SPS. The directional coupler has been chosen as monitor for its accuracy, directivity and simple construction. Due to the directivity of the coupler, the beam position can be measured separately, for p and p beams, even in the zone of interaction. The new superheterodyne 200 MHz receiver and synchronous detector are capable of measuring the beam position of single bunches, shorter than 5 ns at intervals of > 1 μs, as well as continuous beams bunched at 200 MHz CW. The same system can be used both in the transfer lines and in the ring, for single passage or closed orbit measurements of all or individual single bunches. The resolving power of the position measurement amounts to 0.02 mm, as was demonstrated by beam tests. Momentum differences Δp/p ≥ 5.10−5 can be detected between different bunches at injection.