A luminosity monitor using the coherent beam-beam interaction

A new method of monitoring the luminosity has been developed at CESR. The method involves shaking one bunch at a specific frequency and observing the resulting oscillations of the corresponding opposing bunch. In initial tests, 1% accurate measurements have been obtained in 1 second. Measurements of different bunches in a train shows bunch to bunch differences with the optimum conditions for one bunch not coinciding with the optimum for another.