Speaker
Description
All Spallation Neutron Source beamlines use the Experimental Physics and Industrial Control System (EPICS) for sample-environment control, data acquisition, and experiment automation. The Beamline Instrument Data Acquisition and Controls Group supports several sample-environment teams focused on low- and ultra-low-temperature systems and magnets; soft matter; automation and robotics; high-pressure and gas systems; and high-temperature furnaces and sample levitation.
To interface with sample-environment equipment, we support hardware connections and communication protocols including EtherNet/IP for programmable logic controllers, Modbus, PROFIBUS, text-based TCP/IP, Standard Commands for Programmable Instruments (SCPI), JSON, MQTT, LabVIEW-based systems, and direct analog and digital control. This flexibility allows commercial, in-house custom-built, legacy, and PLC-controlled equipment to be integrated into a common EPICS architecture.
Controlled equipment includes magnets of various sizes and operating ranges, including a 14-tesla uncompensated magnet; ultra-low-temperature systems, including dilution refrigerators reaching 30 mK and cryostats; high-temperature furnaces reaching 1,600 °C; rheometers, ultrasonic systems, and high-performance liquid chromatography pumps; high-pressure systems operating up to 70,000 psi; and high-voltage systems operating up to 10 kV. Other examples include gas-mixing systems that combine gases at controlled ratios and flow rates, pneumatic and electrostatic levitators, and robotic arms for automated sample handling, liquid pipetting, and mixing.
The control workflow begins with an EPICS input/output controller that communicates with the hardware and publishes read and write process variables through Channel Access on the protected instrument network. CSS/Phoebus graphical interfaces allow users and instrument staff to monitor status, modify operating parameters, and control equipment. EPICS access security determines who may write to restricted process variables.
Important sample-environment process variables are archived at configured sampling rates and tolerances and retained indefinitely, providing a long-term record of experimental conditions and equipment performance. EPICS autosave stores setpoints locally so they can be restored after an IOC restart. Selected process-variable values are embedded in the final experimental run file for analysis alongside the neutron-scattering data. Alarm conditions can also generate notifications for Instrument Hall Coordinators, providing continuous operational coverage.
Users automate experiments through Scan Server scripting, CSS/Phoebus table scans, and Python scripts. These tools coordinate devices and modify process variables according to predefined sequences or conditions determined by beam exposure time, accumulated proton charge, neutron counts, equipment status, or data from other subsystems. At selected beamlines, authorized users can also securely submit AI-driven experimental sequences from a separate internal network, including workflows for an AI-enabled pipetting robot. This architecture unifies hardware communication, graphical interfaces, access security, archiving, alarms, experiment metadata, and automated execution within EPICS.
Key Words
EPICS, Sample Environment, Instrument Controls, Ultra-Low Temperatures, Robotics, Automation, Controls