Development of a high-precision electrometer at NSLS-II

A high-precision electrometer has been developed at NSLS-II. It is capable of measuring current across six different ranges, from 100 nA to 10 mA, with a resolution ranging from 200 fA to 20 nA. Additionally, it can be used for X-ray Beam Position Monitoring (XBPM) in beamlines and frontends, enabling real-time X-ray beam position monitoring. The newly designed third-generation NSLS-II electrometer features an enhanced low-noise analog front end, high-resolution 20-bit ADCs (8 channels), and advanced hardware tailored for X-ray beam position feedback. The upgraded electrometer integrates seamlessly with the EPICS control system, incorporating an extended Input/Output Controller (IOC) that supports both the quadEM and pscDriver frameworks through a hybrid driver implementation. Our primary objective is to deploy beamline detectors for current/voltage output monitoring and integrate the X-ray BPM feedback system into the storage ring’s Fast Orbit Feedback (FOFB) system, aiming to achieve superior photon beam stability. This work represents an ongoing collaborative R&D effort among accelerators, DSSI, and beamline teams to enhance beam position control and monitoring capabilities. This paper will present the new electrometer's architecture and performance, its integration with EPICS IOC, and ongoing research developments. Future directions for beam stabilization and control improvements will also be discussed.