HARD REAL TIME QUICK EXAFS DATA ACQUISITION WITH ALL OPEN SOURCE SOFTWARE ON A COMMODITY PERSONAL COMPUTER.

Conference · Wed Apr 25 04:00:00 EDT 2007

OSTI ID:918990

SO, I; SIDDONS, D P; CALIEBE, W A; KHALID, S

We describe here the data acquisition subsystem of the Quick EXAFS (QEXAFS) experiment at the National Synchrotron Light Source of Brookhaven National Laboratory. For ease of future growth and flexibility, almost all software components are open source with very active maintainers. Among them, Linux running on x86 desktop computer, RTAI for real-time response, COMEDI driver for the data acquisition hardware, Qt and PyQt for graphical user interface, PyQwt for plotting, and Python for scripting. The signal (A/D) and energy-reading (IK220 encoder) devices in the PCI computer are also EPICS enabled. The control system scans the monochromator energy through a networked EPICS motor. With the real-time kernel, the system is capable of deterministic data-sampling period of tens of micro-seconds with typical timing-jitter of several micro-seconds. At the same time, Linux is running in other non-real-time processes handling the user-interface. A modern Qt-based controls-front end enhances productivity. The fast plotting and zooming of data in time or energy coordinates let the experimenters verify the quality of the data before detailed analysis. Python scripting is built-in for automation. The typical data-rate for continuous runs are around ten mega-bytes per minute.

• Research Organization: Brookhaven National Laboratory
• Sponsoring Organization: Doe - Office Of Science
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 918990
• Report Number(s): BNL--79366-2007-CP; KC0204011
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
AUTOMATION
BNL
COMPUTERS
CONTROL SYSTEMS
DATA ACQUISITION
FLEXIBILITY
MONOCHROMATORS
NSLS
PERSONAL COMPUTERS
PRODUCTIVITY
SYNCHROTRON RADIATION