Performance of magnetostrictive element at LHe environment12th International Conference MIXDES 2005

Performance ofmagnetostrictive element

at LHe environment

M.Grecki, P. Sekalski Department of Microelectronics and Computer Science

Technical University of Lodz, Poland

C.Albrecht Deutsches Elektronen-Synchrotron

Hamburg, Germany

Performance of magnetostrictive element at LHe environment12th International Conference MIXDES 2005

Outline

• Motivation of experiment,

• Magnetostrictive tuner specification,

• Experiment description,

• Plans for future,

Performance of magnetostrictive element at LHe environment12th International Conference MIXDES 2005

Motivation for experiment

The change of the resonant frequency of the cavity,

The master oscillator frequency is constant.

The cavities are pulsed at high field.

The electromagnetic field interacts with cavity walls

The cavity changes its dimensions

De-tuned cavity

,

T

T

De-tuned cavity

(Lorentz force)

De-tuned cavity

BEAM PULSE ONBEAM PULSE ON

Magnetostrictive elements:• might have a higher lifetime, • are immune to shortcuts,• generate less heat,

Magnetostriction of different materials in function of temperature

(courtesy of ENERGEN).

Performance of magnetostrictive element at LHe environment12th International Conference MIXDES 2005

Magnetostrictive tuner specifications

5 x 1010 CyclesLifetime:

1.6 msPulse Length:

< 0.1 WHeat Load to 2.1 K:

60 per secondRepetition Rate:

< 25mG at 30 mm from actuatorStray magnetic field:

3 kNLoad:

2.1 KOperating Temp:

0.15 µm/ µsecSlew rate:

better than 0.2 µmResolution:

20 µm (preload 1500N)Stroke:

Dimensions:

Specification Parameter

61.8 mm High x 50 mm Wide x 22 mm Deep

5 x 1010 CyclesLifetime:

1.6 msPulse Length:

< 0.1 WHeat Load to 2.1 K:

60 per secondRepetition Rate:

< 25mG at 30 mm from actuatorStray magnetic field:

3 kNLoad:

2.1 KOperating Temp:

0.15 µm/ µsecSlew rate:

better than 0.2 µmResolution:

20 µm (preload 1500N)Stroke:

Dimensions:

Specification Parameter

61.8 mm High x 50 mm Wide x 22 mm Deep

KELVIN ALL®

0

500

1000

1500

2000

2500

3000

0 20 40 60 80 100 120 140 160

magnetic field (H) [Am-1]

mag

net

ost

rict

ion

(p

pm

)

4.2K77K293K

22 mm50 mm

61.8

mm

Performance of magnetostrictive element at LHe environment12th International Conference MIXDES 2005

Magnetostrictive tuner prototype

Plunger & Belleville springs

Active magnetostrictive element with ferrite, s.c. coil and thermal

connectors

Niobium Cover

Magnetostrictive rod(made of Kelvin ALL®)

Build by ENERGEN Inc.

Ferrite necessary to close magnetic circuit

Superconducting coil (Nb3Sn)

Thermal connectors

Performance of magnetostrictive element at LHe environment12th International Conference MIXDES 2005

Magnetostrictive tuner experimentExperiment goals• Run tuner at low temperature,• Transfer function from magnetostrictive

element to piezoelectric one • Transfer function from piezoelectric

element to magnetostrictive one• Characterize magnetostrictive tuner

vs. NOLIAC piezo stack (similar experiment with two piezostacks was

done)

- stroke vs applied current- maximal frequency

• Heat dissipation (temperature rise)

Performance of magnetostrictive element at LHe environment12th International Conference MIXDES 2005

Power Transconductance Amplifier

Technical Specifications:

• Maximum output current amplitude – 8 A

• Maximum pulse duration – 2.3 ms

• Maximum repetition frequency – 20 Hz

• Amplification – 3.33 A/V

Schematic of amplifier (designed by G. Jablonski, DMCS-TUL)

PTA based on PA93 APEX

Power Operational Amplifier

PWM amplifier is under investigation

Performance of magnetostrictive element at LHe environment12th International Conference MIXDES 2005

Magnetostrictive tuner experiment

0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

0 2 4 6 8

input current [A]

ou

tpu

t vo

ltag

e [V

]

0

1

2

3

4

5

6

7

8

9

0 1 2 3 4 5 6 7 8

input current [A]

dis

pla

cem

nt

[um

]

mesurement (constant voltage/load factor)

data from Energen

mesurement (variable voltage/load factor)

Peak Piezo Voltage vs. Applied Load

0

5

10

15

20

25

30

35

0 50 100 150 200Applied Load [kg]

Pe

ak

Pie

zo V

olt

ag

e [

V]

Room T

T = 7 - 16 K

The data obtained by Energen „is” done for

preload of 400N. (no measurement for

preload was performed at LHe

temperature)

Measured data Calibration data from INFN

~2μm of displacement for 8A

Performance of magnetostrictive element at LHe environment12th International Conference MIXDES 2005

Magnetostrictive tuner - future test

• Two new magnetostrictive rods from EXTREMA are ordered. They are made of GalFeNOL.

• We would like to perform a characterization of all 3 rods (or more if possible) similar to the piezo one, including:– Displacement measurement versus magnetic field applied to device for

different preload settings (i.e. 0N, 1kN, 2kN, 3kN),

– Max. stroke,

– Dynamics of motion,

– Heat generation – coil is made of Nb3Sn,

– Magnetic field distribution (if possible)

Performance of magnetostrictive element at LHe environment12th International Conference MIXDES 2005

50 mm

62 mm

Flange for high current wires

(up to 16 Amps) Flange for temperature and magnetic field sensors wires

Interface need to be designed

Displacement sensor

Magnetic field sensors

Magnetostrictive rod inside superconducting coil

Membrane

Screw for preload force adjustment

Temperature sensors(its positions are under

investigation )

Magnetostrictive tuner - future test

Performance of magnetostrictive element at LHe environment12th International Conference MIXDES 2005

Conclusions

The maximal displacement of magnetostrictive tuner was less than 2um. The data might be not exact, because the preload force and boundary condition

were not well controlled (It might happen that the preload force was higher than 1kN, because stiffness of fixture was unknown at low temperature).

Small delay between input and output signal might be observed (around 70us). In principle it might be explained by the magnetostrictive element hysteresis

(as it is observed in RT temperature).

Finally, performed experiment does not give the quantify results, but the main goal of test was reached: the tuner was run successfully at LHe temperature.

On the other hand, the detailed magnetostrictive rod characterization is strongly required. Using the obtained experiences, the proper experiment will be prepared

and performed soon.

Performance of magnetostrictive element at LHe environment12th International Conference MIXDES 2005

References

[1]   “TESLA Technical Design Report”, DESY 2001-011, 2001

[2]   T. Schilcher, “Vector Sum Control of Pulsed Accelerating Field in Lorentz Force Detuned Superconducting Cavities“, PhD thesis

[4]   S.N. Simrock, “Lorentz Force Compensation of Pulsed SRF Cavities”, Proceedings of LINAC 2002, Gyeongju, Korea

[5]   M. Liepe, W.D.-Moeller, S.N. Simrock, “Dynamic Lorentz Force Compensation with a Fast Piezoelectric Tuner”, Proceedings of the 2001 Particle Accelerator Conference, Chicago

[6]   L. Lilje, S. Simrock, D. Kostin, M. Fouaidy, “Characteristics of a fast Piezo-Tuning Mechanism for Superconducting Cavities”, Proceedings of EPAC 2002, Paris, France.

[7]   P. Sekalski, S. Simrock, L. Lilje, C. Albrecht, “Lorentz Force Detuning Compensation System for Accelerating Field Gradients up to 35 MV/m for Superconducting XFEL and TESLA Nine-Cell Cavities”, MIXDES 2004, Poland

[8]   Magnetostrictive tuner datasheet, ENERGEN, INC

Performance of magnetostrictive element at LHe environment12th International Conference MIXDES 2005

Thank you for your attention