What is it about?

The absolute beam charge of a single-bunch electron beam with a pulse width of 10 ps and that of a short-pulsed electron beam with a pulse width of 1 ns were measured with a Faraday cup in a beam test for the KEK B-Factory (KEKB) injector linac.

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Why is it important?

It is strongly desired to obtain a precise beam-injection rate to the KEKB rings, and to estimate the amount of beam loss. A wall-current monitor was also recalibrated within an error of $\pm2\%$.


Although beam-charge monitors with electromagnetic pickups are widely used, accurate calibration methods for absolute beam charge have been little discussed previously. Several calibration methods can be applied to other linear accelerators generating pulsed beams with pulse widths in the range of nanoseconds or less. A new method for beam-charge calibration using beam-induced fundamental longitudinal wakefield, which does not depend upon the pulse characteristics of the beam in principle, but depends only upon the amount of beam charge. Another method for absolute beam-charge calibration using a Faraday cup (FC) has been performed because the response does not depend on the pulse width of the beams.

Dr. Tsuyoshi Suwada
High Energy Accelerator Reseach Organization (KEK)

Read the Original

This page is a summary of: Absolute Beam-Charge Measurement for Single-Bunch Electron Beams, Japanese Journal of Applied Physics, February 2000, Institute of Physics Publishing,
DOI: 10.1143/jjap.39.628.
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