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Outline

Explore the requirements, magnetic moment measurements, sorting techniques, and field measurements of magnets for the LCLS prototype. Discover the impact of phase errors and pole height on magnetic field quality. Detailed analysis and conclusions are presented.

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Outline

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  1. Outline • 1.LCLS Requirements • 2.Magnetic Moment Measurements • 3. Sorting • 4. Vertical Field Measurements • 5. Horizontal Field Measurements • 6. Conclusion I. Vasserman, ANL/APS/ID&FEL

  2. I. Vasserman, ANL/APS/ID&FEL

  3. Sorting • 1.Main component of magnetic moment • 2.    Field integrals • 3.    Pole height and cant • 4.    Phase errors I. Vasserman, ANL/APS/ID&FEL

  4. I. Vasserman, ANL/APS/ID&FEL

  5. I. Vasserman, ANL/APS/ID&FEL

  6. X-axis: Slot Number Y-axis: Total magnetic moment I. Vasserman, ANL/APS/ID&FEL

  7. I. Vasserman, ANL/APS/ID&FEL

  8. I. Vasserman, ANL/APS/ID&FEL

  9. Data From Half-period Model Here J1 is first field integral,  is an undulator period, and  is the phase. I. Vasserman, ANL/APS/ID&FEL

  10. Phase calculations are very sensitive to initial conditions: Special software was created. • It gives us some approximation about quality of magnets. • Measurements: Bottom magnet is in place all the time. • Horizontal field integrals were negligible. • Tuning of magnets includes the first field integrals rather than the vertical component of magnetic moment. I. Vasserman, ANL/APS/ID&FEL

  11. Example of vertical component of magnetic moment measurement. Red: measured, blue: calculated (Radia). Signature was obtained by subtracting data with vertical components of top and bottom magnets in one direction and in opposite direction. I. Vasserman, ANL/APS/ID&FEL

  12. 100 80 60 40 20 0 -20 -40 -60 J1p Aver=27.1 Jin Aver= -10.6 -80 -100 0 50 100 150 200 250 300 350 400 450 500 Magnet First Field Integral (G-cm) for LCLS prototype magnets with positive component of magnetic moment (red) and negative (blue). I. Vasserman, ANL/APS/ID&FEL

  13. 2.0 1.5 1.0 0.5 0.0 -0.5 -1.0 -1.5 -2.0 -2.5 -3.0 -3.5 -4.0 V_sdev= 1.34691 -4.5 0 50 100 150 200 250 300 350 400 450 500 Magnet 2.0 1.5 1.0 0.5 0.0 -0.5 -1.0 -1.5 -2.0 -2.5 -3.0 -3.5 V_sdev(-)= 1.25171 -4.0 V_sdev(+)= 1.201 -4.5 100 150 200 250 300 350 400 450 500 0 50 Magnet Phase errors vs. magnets for LCLS prototype Top: all magnets, bottom: separate, for positive vertical componentof magnetic moment (blue) and negative (red) I. Vasserman, ANL/APS/ID&FEL

  14. Poles height and cant • Sorting of pole height was done to achieve the best possible gap uniformity along the device. • Cant was sorted in such a way as to provide easy access for mechanical measurements of the gap using gauge ceramic blocks and to avoid accumulation of horizontal field integrals. • Device ends will have a possibility of remote gap tuning. I. Vasserman, ANL/APS/ID&FEL

  15. Measurements of First 2 Sections • First 2 sections (79 poles) were installed. • First and second field integrals were measured. • Vertical Field: Some tuning was necessary due to gap difference. Main tuning was required for the ends (1/3 of maximum shim strength) • Horizontal Field: No tuning was required. • Keff is 3.91 instead of 3.71. Gap will be increased to achieve design value. • Keff temperature dependence was measured. Keff/Keff is 0.0005 per 1C. It is close to calculated numbers, taking into account gap and magnetic moment temperature dependence. I. Vasserman, ANL/APS/ID&FEL

  16. 2.0 2 1.0 1 0.0 0 Trajectory after tuning(µ) -1.0 Trajectory before tuning(µ) -1 -2.0 -2 -3.0 -3 -4 -4.0 -800 -600 -400 -200 0 200 400 600 800mm Z(mm) Horizontal trajectory vs. distance before tuning (red) and after (blue) for first 2 sections. Tolerances are 2µm I. Vasserman, ANL/APS/ID&FEL

  17. 2. 1. Vertical Trajectory(µ) 0.0 - -1. -2. -800 -600 -400 -200 0 200 400 600 800 Z (mm) Vertical trajectory without tuning I. Vasserman, ANL/APS/ID&FEL

  18. Conclusion • First measurements results show: Quality of magnets Design of the device and sorting are good enough already. • Tuning was rather modest. • It is clear how to implement further improvements to decrease/eliminate necessary tuning. I. Vasserman, ANL/APS/ID&FEL

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