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Theory and applications of the vibrating stretched wire technique for high-precision quadrupole alignment Alexander Temnykh Cornell University, Ithaca.

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Presentation on theme: "Theory and applications of the vibrating stretched wire technique for high-precision quadrupole alignment Alexander Temnykh Cornell University, Ithaca."— Presentation transcript:

1 Theory and applications of the vibrating stretched wire technique for high-precision quadrupole alignment Alexander Temnykh Cornell University, Ithaca NY, USA 1 st PACMAN Workshop, CERN Feb

2 May 11, st PACMAN Workshop, CERN Feb 2-4, Outline Theory of vibrating wire (VW) magnetic field measurement technique High-precision quadrupole alignment – CESR super-conducting quadrupole fiducialization at room temperature –CESR final focusing quadrupoles in-situ alignment –NSLS-II (BNL) quadrupole and sextupole magnets alignment on girders –LCLS (SLAC) quadrupole fiducialization –SwissFEL quadrupole fiducialization –Small aperture quadrupole magnets characterization at CERN Other applications –Solenoid magnets magnetic axis finding –CHESS G-line PM wiggler field integrals tuning –LCLS undulator field integrals characterization Conclusion

3 Theory May 11, st PACMAN Workshop, CERN Feb 2-4, Damping Gravity Lorenz forces between magnetic field and driving current Taut wire free motion Setup Motion equation A. Temnykh, Vibrating wire field-measuring technique, NIMA 399 (1997) with boundary condition: General solution GravityWire motion induced by Lorentz forces Gravity termwith minimum(sag) at and can be represented in the similar way: Wire vibrating mode amplitude ; ; Term in the magnetic field Fourier sine series expansion

4 Theory Dipole magnet field reconstruction Test dipole magnet at x = 45cm position. Quadrupole magnet alignment Wire length ~1.15 m, for the field reconstruction 13 vibrating modes are used. Wire length ~3.15 m, for the field reconstruction 30 vibrating modes are used A. Temnykh, Vibrating wire field-measuring technique, NIMA 399 (1997) Test Quadrupole location Demonstration experiments

5 Application / CESR SC quads fiducialization at room temperature May 11, st PACMAN Workshop, CERN Feb 2-4, A. Temnykh, The Use of Vibrating Wire Technique for Precise Positioning of CESR Phase III Super- Conducting Quadrupoles at Room Temperature, PAC × 10 −2 T/m at room temperature Setup

6 Application / CESR Final Focus Quadrupole magnets alignment May 11, st PACMAN Workshop, CERN Feb 2-4, A. Temnykh and S. Chapman, Alignment of the CESR interaction region qudrupole magnets using vibrating wire technique, IMMW 14 (2005) Challenges: 1.Long wire 2.Mix of PM and SC quads 3.1T longitudinal CLEO solenoid field Q0E/W – permanent quadrupole magnets Q1E/W and Q2E/W super-conducting quadrupole magnets in cryostats (1) – 7.536m long 0.1mm copper-beryllium wire (2) – precise movable stages with optical targets. (3) – constant tension mechanism. (4) – wire motion sensors CESR interaction region assembly view Setup

7 Application / CESR Final Focus Quadrupole magnets alignment May 11, st PACMAN Workshop, CERN Feb 2-4, Wire vertical position at Q0E,W Differential effect dy = - 0.1mm Y = 0.039mm Vertical vibration mode amplitudes Reconstructed horizontal magnetic field, B x (z) Q0W Q0E Q0WQ0E Y = mm PM quadrupoles survey/alignment we used with 30 vibration modes A. Temnykh and S. Chapman, Alignment of the CESR interaction region qudrupole magnets using vibrating wire technique, IMMW 14 (2005)

8 Application / CESR Final Focus Quadrupole magnets alignment May 11, st PACMAN Workshop, CERN Feb 2-4, For Q1E,W SC quadrupoles survey used 4-th order field vibration mode Q1W, vertical survey Q1W, horizontal Surveyed magnets 1) I(Q1W) = 233A x = mm 2) I(Q1W) = 466A x = mm 1) I(Q1E) = 231A y = mm 2) I(Q1E) = 466A y = mm Q1E, vertical 1) I(Q1E) = 231A x = mm 2) I(Q1E) = 466A x = mm Q1E, horizontal 1) I(Q1W) = 243A Y = mm 2) I(Q1W) = 465A Y = mm A. Temnykh and S. Chapman, Alignment of the CESR interaction region qudrupole magnets using vibrating wire technique, IMMW 14 (2005)

9 Application / CESR Final Focus Quadrupole magnets alignment May 11, st PACMAN Workshop, CERN Feb 2-4, MagnetGradient [T/m] Length [m] Horizontal position [mm] Vertical position [mm] Q2E - SC Q1E - SC Q0E - PM Q0W - PM Q1W - SC Q2W - SC Electron beam orbit measurement confirmed the data CESR final focusing quadrupole survey data, Jan A. Temnykh and S. Chapman, Alignment of the CESR interaction region qudrupole magnets using vibrating wire technique, IMMW 14 (2005)

10 Application / NSLS-II magnet system alignment May 11, st PACMAN Workshop, CERN Feb 2-4, NSLS-II girder with magnets Girder length ~ 5 m Alignment Specifications: 30 µm magnet-to-magnet; ±0.2 mrad magnet roll; 100 µm girder-to-girder; Because it was difficult to achieve the required accuracy using magnet fiducialization, coupled with optical survey, Vibrating Wire technique was adopted. Quadrupoles Sextupoles Steering magnets 7.3m long wire Movable wire stages, two sets of vertical and horizontal wire vibration sensors µm wire sag Various types of magnets (sextupoles and quads) Mass production A. Jain, VIBRATING WIRE R&D FOR ALIGNMENT OF MULTIPOLE MAGNETS IN NSLS-II, The 10th International Workshop on Accelerator Alignment, KEK, Tsukuba, February 2008

11 Application / NSLS-II magnet system alignment May 11, st PACMAN Workshop, CERN Feb 2-4, (1) A. Jain, VIBRATING WIRE R&D FOR ALIGNMENT OF MULTIPOLE MAGNETS IN NSLS-II, The 10th International Workshop on Accelerator Alignment, KEK, Tsukuba, February 2008 (2) A. Temnykh and A. Jain, Determination of Magnetic Axis in a Sextupole magnet using Vibrating Wire Technique, 15th IMMW, FNAL, 2007 Quadrupole magnets alignment (1) Sextupole magnets axis finding (2)

12 Application / LCLS quadrupole magnets fiducialization May 11, st PACMAN Workshop, CERN Feb 2-4, Wire Length 1.477m, fundamental frequency 115Hz, driving current ~7mA, sag ~23 microns The second vibrating mode not sensitive to uniform Earth magnetic field was used for alignment. The driving AC current frequency was maintained on resonance all time. Tooling balls served as references. FARO arm Coordinate Measurement Machine was used to find magnet tool balls position relative to wire position detector. Wire to quadrupole axis alignment precision was better than 1 micron. Tool ball on quads to quad magnetic center precision ~15 micron Mass production ! Z. Wolf et. al., A Vibrating Wire System For Quadrupole Fiducialization, presentation on IMMW 14 (2005)IMMW 14 Z. Wolf, A Vibrating Wire System For Quadrupole Fiducialization, LCLS-TN M. Levashov and Z. Wolf, Set Up and Test Results for a Vibrating Wire System for Quadrupole Fiducialization, LCLS- TN Fixed wire, movable quad stage

13 Application / Swiss FEL quadrupole magnets fiducialization May 11, st PACMAN Workshop, CERN Feb 2-4, Wire Length 1.2 m, fundamental frequency ~101 Hz, driving current ~ 75mA The second vibrating mode was used for alignment. FARO arm Coordinate Measurement Machine was employed to measure magnet references position relative to wire pins. The driving current frequency was maintained on resonance all time using lock-in-amplifier with Phase Lock Loop (PLL) function. With PLL function ON, demonstrated resolution is ~ 0.2 micrometer. For 0.36T quadrupole (0.17m long, 2.1 T/m gradient) 0.2 micron resolution implies G-cm field integral sensitivity! C. Wouters et. al., Vibrating Wire Technique and Phase Lock Loop for Finding the Magnetic Axis of Quadrupoles, IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 22, NO. 3, JUNE 2012 V. Vrankovic et. al., A Method for the Submicrometer Accuracy Determination of Quadrupole Magnetic Axis, IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 24, NO. 3, JUNE 2014 MagnetWire vibration sensor Setup PLL OFF PLL ON Fixed quad, movable wire stages

14 Application / CERN – characterization of a small aperture quadrupole May 11, st PACMAN Workshop, CERN Feb 2-4, Wire Length ~1.0 m, off resonance operation, Vibration amplitude (displacement) is proportional to magnetic field at wire location P. Arpaia et. al., Magnetic field measurements on small magnets by vibrating wire systems, IEEE Instrumentation and Measurement Technology Conference 01/2011 Setup Fixed quad, movable wire stages Quadrupole Wire vibration sensor Wire locations in the course of measurements (on circle) quadrupole sextupole octupole etc.

15 Application / Solenoid alignment May 11, st PACMAN Workshop, CERN Feb 2-4, Solenoid alignment technique has been used for Cornell ERL injector focusing solenoids fiducialization. A. Temnykh, Application of the VW technique for the solenoid magnet magnetic center finding, IMMW 14 (2005)

16 Application / Solenoid alignment May 11, st PACMAN Workshop, CERN Feb 2-4, A. Temnykh, Application of the VW technique for the solenoid magnet magnetic center finding, IMMW 14 (2005)

17 Application / G-line wiggler tuning May 11, st PACMAN Workshop, CERN Feb 2-4, A. Temnykh, THE CHESS G-LINE WIGGLER TUNING, PAC2001 First and second field integrals tuning MULTIPOLE FIELD ERRORS CORRECTION (the source location was found with vibrating wire) CHESS G-line Wiggler (PM) Period [cm]12 Number of poles50 Peak field [T]0.78 T Length [m]3 m

18 Application / LCLS undulator characterization May 11, st PACMAN Workshop, CERN Feb 2-4, Single shim effect. The field change was measured and reconstructed using 25 vibrating modes Vertical beam trajectory Horizontal beam trajectory Beam trajectories calculated for Hall probe and Vibrating Wire measured field. A. Temnykh, Y. Levashov and Z. Wolf, A study of undulator magnets characterization using the vibrating wire technique, NIMA 622 (2010) 650–656

19 Conclusion After it was developed in 1997, Vibrating Wire technique has been used in many occasions and became a standard tool. For several big projects VW technique was critical. More applications can be expected. May 11, st PACMAN Workshop, CERN Feb 2-4,


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