Measurement of Twiss Parameters Using SFC's (Segmented Faraday Cup).

摘要

The Segmented Faraday Cup (SFC) consists of 48 copper plates that are 1 mm times 75 mm times 10 mm. These plates are stacked against each other on the 75 mm times 10 mm face with a layer of kapton between them for electrical insulation. When the assembly is viewed in the direction of the incident beam, the beam sees 48 vertical electrodes that are 1 mm times 75 mm and 10 mm thick. The copper plates and the kapton are held together in an aluminum frame which is mounted on a rotating shaft. This assembly can be placed in the beam by rotating the shaft. Another SFC of the same construction is also mounted on this shaft. This other SFC, however, has its plates mounted horizontally rather than vertically. Thus by rotating the shaft either the vertical SFC, the horizontal SFC, or a scintillator screen may be placed into the beam. In addition, the shaft can be rotated so that none of these elements are in the beam. The SFC's were used to measure the emittance of the beam by using a scanning slit. The theory and the method for this measurement are presented. A description of the electronics is presented. A sample of a beam profile and the results of an emittance measurement are presented. 2 refs., 5 figs.