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LCLS Undulator Second Prototype (major goals and changes in the design) Emil Trakhtenberg Argonne National Laboratory November 14, 2003. Major Challenge How to resolve it Results of the numerical simulation and first tests. LCLS Second Prototype Undulator (major challenge).
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LCLS Undulator Second Prototype (major goals and changes in the design)Emil Trakhtenberg Argonne National LaboratoryNovember 14, 2003 • Major Challenge • How to resolve it • Results of the numerical simulation and first tests Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator(major challenge) How to make 35-40 LCLS undulators fully identical (K value in the order of 10-4) Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator • Possible solutions: • Variable gap device; • Electrical correction coils; • Temperature control of each individual undulator inside ±3° C; • Something completely new. Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator (temperature control study 1) Air-Cooling/Heating (Enclosure) Advantages Disadvantages • Reduces easy access to Undulators • Not as easy to precisely control air temperature compared to water • Achieving 0.2°C temperature stability is difficult (1°C is more standard) • Fine control can only be achieved by pushing larges volumes of air through the enclosures • Does not impact Undulator Design • Stabilizes the entire structure including diagnostics • Commercially available enclosures can be tailored to our application Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator (temperature control study 2) Water-Cooling Advantages Disadvantages Access to Undulators not restricted Relatively easy to implement cooling design Cooling passages can be integral to the strongback structure Achieving 0.1°C stability with water is relatively easy Poor conduction path between the strongback and magnet holders (may not work as is) Can not easily achieve uniformity along undulator length (gradients) Though reduced, there will still be fluctuations in temperatures as a function of room temperature fluctuations Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator (temperature control study 3) Active Heating Advantages Disadvantages • Very complicated heater layout required to achieve stability and uniformity • Complicates the Undulator design and fabrication • Sophisticated variable power and PID control systems required for each Undulator • Gradients are inherent in the design • Can use commercially available heaters & control system • Fine control is possible if heater layout design is properly done Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator (magnetic shunt scheme for a numerical simulations) Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator (peak field variation with a magnetic shunt) Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator (magnetic shunt attractive forces) Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator Cross Section(with an actuator) • Gearbox for 250 kg; • “Smartmotor “ 3120; • Limit switches for the lower and upper positions; • Potentiometer with 25 microns resolution. Design can be easily modified for manual motion Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator ( with a “comb” actuator) Only one actuator is shown Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator (half of the magnet structure with a modification) Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator ( magnet shunt – a”comb”) Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator (”comb” deflection) Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator (alternate material choice 1) Casting Processes Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator (alternate material choice 2) Suitable Aluminum Alloy535 (Almag 35) • Exceptional Dimensional Stability • Highest combination of • Strength • Shock resistance • Ductility • Superior Corrosion Resistance • Machinability • Machines 4 times faster than other aluminum alloys • Typical uses • instruments and optical equipment requiring high dimensional stability Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator Aluminum Housing Initial 3D Model for Analysis Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator Aluminum Housing Bran’s Analysis Improved Model Emil Trakhtenberg, ANL
LCLS Second Prototype Undulator Titanium Housing Emil Trakhtenberg, ANL
Acknowledgments Isaac Vasserman, Shigemi Sasaki Patric Den Hartog, Elizabeth Moog, Mark Erdmann, John Noonan, Thomas Powers, Branislav Brajuskovic, Glen Lawrence, Jeffrey Collins. Emil Trakhtenberg, ANL