Beam position monitor data acquisition for the Advanced Photon Source

Abstract

4. Measure position at each BPM on each turn ( 3.6 mi-This paper describes the Beam Position Monitor (BPM)croseconds for the storage ring). data acquisition scheme for the Advanced Photon Source 5. Provide averaged beam position for higher accuracy.(APS) storage ring. The storage ring contains 360 beam posi-6. Provide a beam history for each BPM.

Advanced photon source monopulse RF beam position monitor front-end upgrade

“…The RFBPM processing electronics are located above the tunnel in 40 VXI crates with 9 channels per crate (2). The RFBPM signal processing topology used for the APS storage ring is a monopulse amplitude-to-phase (AM/PM) technique for measuring the beam position in the x-and y -axes.…”

“…This device is basically a pulse repeater that delays each pulse or bunch of pulses by multiples of 2.84 nanoseconds with respect to each other. The result is a (SIN F/F) 2 response that has good matching characteristics unit to unit and good cancellation over all frequencies and times. The filter must be designed such that a minimum of 24 pulses, or 24 × 2.84 ns, are generated, which will yield a 68 ns pulse train.…”

New APS storage ring BPM timing system design

“…Figure 2 shows a simplified diagram of the BPM trigger module. This module replaced the VXI BPM timing module described in reference [1]. It provides the nine output triggers for a single sector of SCDUs.…”

“…SCDUs, as originally designed, triggered on the beam signal. Timing provided an "arm" signal, which selected the stored bunch each SCDU would use as a trigger [1]. The SCDU used a threshold comparator circuit for the beam-derived trigger and thus suffered from an intensity-dependent trigger walk.…”