1. LCLS-II Magnetic Structure Design Review Steve Marks 7/6/11 1

2. Agenda IntroductionS. Marks Summary of relevant physics requirements, design elements affecting magnet blocks S. Marks Conceptual mechanical designA. Black Magnetic structure assembly conceptA. Black Analysis of one vs. two blocks per poleD. Arbelaez End Design – TheoryR. Schlueter Baseline magnetic designS. Marks Magnetic analysis, results Quarter period model, results End design J.-Y. Jung Procurement strategy, magnet specificationD. Munson Conclusions, recommendationsS. Marks Slide 2Undulator Alternatives- 5m 6-15-11

3. Review Context and Objective Prepare for procurement of first prototype  A total of four HXU* Magnet Modules, two each from two vendors Two operational magnet test units (top and bottom module pairs) End modules included  Objective: Qualify two magnet material vendors, and establish firm cost Qualify the periodic magnet design Test and qualify the end design Test tuning + other tests Slide 3Magnetic Structure Conceptual Design Review 7/6/11 *We want to compare blocks of the same variety from two different vendors. HXU is chosen because of the more demanding requirements.

4. Review Context and Objective Magnetic material procurement drives the schedule, so want to accelerate this procurement The overall magnetic design will be presented at a conceptual design level, but want to concentrate on those aspects that directly affect magnet blocks Desired outcome from review: approval to proceed with block procurement, or identification of modifications necessary before procurement Procurement of remaining magnet module components and assembly will follow by approximately two months Conceptual design review for overall system early August Slide 4Magnetic Structure Conceptual Design Review 7/6/11

5. Relevant Physics Requirements Related Design Elements Peak B eff : 1.93 T (SXU), 1.26 T (HXU)  Choice of magnet material ( B r, H cj )  Height of pole, overhang of magnet material Horizontal field roll off: |  K/K| = 1.5×10 -4 (SXU), 5.4×10 -5 (HXU) at ±0.4mm  Pole and block width |  B y dz| < 40  Tm, |  B y dz 2 | < 50  Tm 2  With even number of poles, systematic  B y dz = 0  Systematic  B y dz 2 related to end design (size of last three blocks), gap variation Offset Entrance (and exit) kick have to be less than 14.7  Tm Tolerance on trajectory (non-systematic part of  B y dz 2 ), phase errors/shake  Result of block non-uniformity, pole placement errors  Number of blocks per pole, sorting  Tuning mechanism(s), variation over gap range Slide 5Magnetic Structure Conceptual Design Review 7/6/11

6. Conceptual Mechanical Design Alan Black Slide 6Magnetic Structure Conceptual Design Review 7/6/11

7. One vs. Two Blocks Diego Arbalaez Slide 7Magnetic Structure Conceptual Design Review 7/6/11

8. Magnetic End Design – Theory R. Schlueter Slide 8Undulator Alternatives- 5m 6-15-11

9. Baseline Magnetic Design Magnetic material:  B r = 1.32 T, H cj = 21 kOe  Examples: VACODYM 854TP, NEOMAX 44AH, Shin Etsu N42SH SXU  Peak B eff = 1.91 T (1.93 T)   B/B| 0.4mm = 2.3×10 -5 (1.5×10 -4 ) HXU  Peak B eff = 1.28 T (1.26 T)   B/B| 0.4mm = 2.4×10 -5 (5.4×10 -5 ) Slide 9 HXU Pole/Block SXU Pole/Block Magnetic Structure Conceptual Design Review 7/6/11

10. Magnetic Analysis J.-Y. Jung Slide 10Undulator Alternatives- 5m 6-15-11

11. Magnetic Material Procurement Dawn Munson Slide 11Magnetic Structure Conceptual Design Review 7/6/11

12. Conclusions and Recommendations The baseline design meets requirements A modest savings (probably less than $1M) could be realized if peak field requirement is relaxed for SXU by ~3% – Not recommended The use of two blocks per pole offers a significant advantage if coupled with appropriate sorting algorithm, will reduce the effort and risk during tuning – Recommended Solicit bids for both HXU and SXU blocks – Initial procurement of HXU blocks HXU end design meets requirements over most of gap range, will verify with prototype, initial SXU design scaled from HXU, but need to tweak – Better control will require active control (coil around end pole); will test with prototypes Slide 12Undulator Alternatives- 5m 6-15-11