Overview
X-ray / photon beam measurement targets beamline front ends and endstations, providing online monitoring of beam spot position, angle, intensity, slow drift and fast feedback stability. A typical system uses an XBPM/PBPM as the front end, where four blade electrodes generate the photocurrents IA, IB, IC and ID. After low-noise I/V conversion, filtering, ranging and protection, synchronous ADC sampling and FPGA/DSP processing, the system performs dark-current subtraction, normalization and position computation, and outputs X / Y / SUM and status together with FA fast data and SA slow data.
The system is compatible with the EPICS control system and can support kHz-level beam spot stabilization feedback and engineered deployment at beamline stations.