Longitudinal emittance measurements in the Fermilab Booster

I have installed a system to measure the longitudinal emittance over the entire acceleration cycle in the Fermilab Booster accelerator. Measured inputs to the system are the total beam current, the RF voltage per turn seen by the beam, and a diode-detected resistive wall signal. These signals are digitized by an oscilloscope and transferred to the Fermilab control system computers. The bucket area is calculated using the measured RF voltage per turn and the design synchronous phase and ramp rate. The bunch length is taken as the ratio of the total charge to the peak-detected current and, together with the bucket area, can be used to calculate the longitudinal emittance. This system can measure the emittance or bunch length over the entire booster cycle at a 1 kHz sampling rate or over shorter periods (for example, around extraction) at up to a 10 MHz rate. We discuss operational uses of this system