170 likes | 181 Views
Analysis of the Phase Drift in the Main Drive Line and L2 Reference Lines along the LCLS Using MATLAB. By: Guy Grubbs II. Introduction.
E N D
Analysis of the Phase Drift in the Main Drive Line and L2 Reference Lines along the LCLS Using MATLAB By: Guy Grubbs II
Introduction • The Main Drive Line (MDL) and L2 Reference Line (L2) at the Stanford Linear Accelerator Center are used in timing the klystrons which power the accelerator structure. • These signals will be involved in accelerating a very finely compressed bunch of electrons which must travel on phase of the electromagnetic (EM) waves that come from the klystrons.
Timeline of Project • Research • Data Collection • Data Analysis • Conclusions
Research • Main Drive Line: Expansion Joints securely fastened to concrete floor along accelerator • L2: Heliax cable used, dielectric increases velocity of RF wave to compensate for additional distance travelled
Thermal Expansion • Happens in signal lines as well • Change in distance changes amount of power delivered to accelerator structure
Data Storage • The Stanford Linear Collider Control Program (SCP) system • Experimental Physics and Industrial Control System (EPICS) system • Head to Tail Monitor • Temperature • Slow Phase and Amplitude Controller (SPAC)
Data Collection (cont.) • Collected every 6 minutes • Ran at all times • Checks for old data each time program is started • Will continue running until the array is filled if left to itself
Data Analysis (cont.) • Updates to new data on being run • Outliers eliminated • Displays relationships between different data • Allows user to set parameters quickly and easily
Results • Average drift from sectors 22-24: 3.23 degrees S-Band per degree Celsius • Drift at sector 25: 3.20 degrees S-Band per degree Celsius • Difference in L2 and MDL phase drift from sector 22 to sector 24: 3.23-3.20 = .03 degrees S-Band per degree Celsius • Small difference between MDL and L2 phase drifts with respect to temperature
Results (cont.) • Sector 29 has a very low correlation coefficient (.37) • Sector 30 has a nonlinear relationship • 27-28 Feedback may be causing problems, or monitors need replaced Sector 30
Proposed Solutions to Drift • Liquid Hydrogen Cooling • Fiber Optics • Beam Cavities
Acknowledgements • Ron Akre • Vojtech Pacak • SULI Program Staff • Fellow SULI participants