BEAM SCRAPING FOR LHC INJECTION: HIGH LEVEL APPLICATION DEVELOPMENT

The Large Hadron Collider (LHC) at CERN (European Organization for Nuclear Research) will be the world's most powerful accelerator when it is commissioned during 2008. To operate the LHC, injection of very high intensity beams from the Super Proton Synchrotron (SPS) pre-accelerator is required. With intensities of more than 3 _ 1013 p=cycle, it is essential that there is virtually no beam halo present. Such particles can hit the LHC beam pipe, and may cause magnet quenches due to heating. Fast scrapers have been installed in the SPS to measure and remove any halo before the beam is extracted towards the LHC. Fast scrapers have been chosen because there is too little time available for beam cleaning with large collimators. The scraper hardware has been in place in the SPS ring for several years. A low level computer for controlling the scrapers is also in place. A high level control application was, however, not written at the time. The development of the missing high level control application is the subject of this work. The functional requirements for the application have been established in a report by G. Arduini and H. Burkhardt [2]. The application had to be written in Java to be compatible with the control system in the Cern Control Centre (CCC). Java is chosen due to portability between operating systems and due to the large number of freely available libraries. A working application for high level control has been devel oped and released into the software repository for the CCC computers. The application has been tested and used for two machine studies. Other users interested in using the scrapers for machine studies and commissioning have also tested the application. These tests indicate that the application works as expected, and can be used by operators in the future. Also, they have provided valuable feedback for further improvements of the application.