Absolute beam-charge measurement for single-bunch electron beams

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 (K EKB) injector linac. It is strongly desired to obtain a precise beam-inject ion rate to the KEKB rings, and to estimate the amount of beam loss. A wall -current monitor was also recalibrated within an error of +/-2%. This repor t describes the new results for an absolute beam-charge measurement for sin gle-bunch and short-pulsed electron beams, and recalibration of the wall-cu rrent monitors in detail.