• P. Chu, R.H. Iverson, P. Krejcik, G.R. White, M. Woodley, J. Wu
  SLAC, Menlo Park, California
• Q. Gan
  IHEP Beijing, Beijing

Funding: Work supported in part by the DOE Contract DE-AC02-76SF00515. This work was performed in support of the LCLS project at SLAC.

XAL, a high-level application framework originally developed by Spallation Neutron Source (SNS), has been adapted by the Linac Coherent Light Source (LCLS) project. The work includes proper relational database schema modification to better suit XAL configuration data requirement, addition of new device types for LCLS online modeling purpose, longitudinal coordinate system change to better represent the LCLS electron beam rather than proton or ion beam in the original SNS XAL design, intensively benchmark with MAD and present SLC modeling system for the online model, and various new features to the XAL framework. Storing online model data in a relational database and providing universal access methods for other applications is also described here.

• G.R. White, A. Chan, P. Chu, E. Grunhaus, P. Krejcik, K. Luchini, M. Woodley
  SLAC, Menlo Park, California

Funding: Department of Energy contract DE-ACO3-76SF00515

We describe an integrated relational database for beamline element configuration and online accelerator modelling for LCLS. It is hosted in Oracle, from which online controls software, optimization applications and feedback, use a programming interface to acquire the element data and model. Database population is by an automated process starting with a MAD deck, which is processed in Matlab to derive text files that describe the beamline elements whose data are uploaded using Oracle Loader, and the resulting Oracle APEX applications and reports are used for survey, cabling, metrology and other facilities. An automated facility for online model generation creates an XAL online model beamline description file using a database query; the resulting model is then tracked, and results can be loaded back into the database. As such, both the design or extant machine model, of the present and all previous model runs are available, and linked to the relevant element configuration. We present the process flow from the MAD design to the database, the database schema, the database applications, the process of generating a machine model, and some scientific software which uses the database.

• S.R. Norum, S. Allison, J. Browne, S. Chevtsov, J.E. Dusatko, K.D. Kotturi, P. Krejcik, J.J. Olsen, T. Straumann, A.J. Tilghman
  SLAC, Menlo Park, California

Funding: SLAC/DOE Contract DE-AC02-76-SF00515

A state-of-the-art Machine Protection System for the SLAC Linac Coherent Light Source has been designed and built to shut off the beam within one pulse during 120 Hz operation to protect the facility from damage due to beam losses. Inputs from beam loss monitors, BPMs, toroids and position switches of insertable beam line devices are connected to a number of Link Node chassis placed along the beam line. Link Nodes are connected with a central Link Processor in a star topology on a dedicated gigabit Ethernet fiber network. The Link Processor, a Motorola MVME 6100, processes fault data at 360 Hz. After processing, rate limit commands are sent to mitigation devices at the injector and just upstream of the entrance of the sensitive undulator beam line. The beam's repetition rate is lowered according to the fault severity. The SLAC designed Link Nodes support up to 96 digital inputs and 8 digital outputs each. Analog signals are handled via standard IndustryPack (IP) cards placed on the Link Node motherboards with optional transition boards for signal conditioning. A database driven algorithm running on the Link Processor provides runtime loadable and swappable machine protection logic.