Mechanical setups Lorentz Force Detuning System Setup Tuners Mechanical setups Lorentz Force Detuning System Setup Lutz Lilje DESY -MPY- 21.08.2018

Frequency Tuner Tuner consists of 2 parts Slow tuner Fast tuner Allow for different thermal shrinkage Correct slow drifts e.g. He pressure Specification: Range: 820 kHz Resolution: 1 Hz /step 2 basic types have been tested Lateral (Saclay) Coaxial (INFN, DESY) Fast tuner Compensate Lorentz-forces df <= 1 kHz in 1 ms Piezoelectric Frequency Tuner Lutz Lilje DESY -MPY- 21.08.2018

Lateral Tuner (Saclay) Design by M. Maurier and P. Leconte based of the MACSE tuner design DLscrew DLarms DLcavity Used in TTF Double lever system: ratio ~ 1/17 Stepping motor with Harmonic Drive gear box Screw – nut system Needs space between cavities Interferes with HOM couplers More compact design seems feasible Lutz Lilje DESY -MPY- 21.08.2018

New Saclay Tuner Design by P. Bosland More compact design possible Cavity should be pre-tuned so that the tuner is not pushing Piezo integrated Available by the end of the year for first tests Lutz Lilje DESY -MPY- 21.08.2018

New Saclay Tuner 2 Lutz Lilje DESY -MPY- 21.08.2018

New Saclay Tuner 3 Lutz Lilje DESY -MPY- 21.08.2018

New Saclay Tuner 4 Lutz Lilje DESY -MPY- 21.08.2018

Coaxial Tuner (INFN, DESY) On the He vessel Tested on the superstructure in TTF (4 units) Magnetic shielding more difficult 2nd design exists Test in CHECHIA done Lutz Lilje DESY -MPY- 21.08.2018

Lorentz Force Detuning System Setup Setup description Single pulse compensation Resonant excitation Problems Lutz Lilje DESY -MPY- 21.08.2018

Lorentz Force Detuning System Setup Function Generator ADC PZD Amplifier Piezo actuator Piezo sensor PZM Amplifier DOOCS server Amplifier Lock-in or Logarithmic Chechia Matlab Fgen.m chread.m LP filter Lutz Lilje DESY -MPY- 21.08.2018

Piezoelectric tuner I M. Liepe, S. Simrock, W.D.-Moeller Tuning mechanism Piezo Piezo-Actuator: l=39mm Umax=150V  l=3m at 2K fmax,static=500Hz He-Tank & Cavity Lutz Lilje DESY -MPY- 21.08.2018

Piezo Tuner setup II Sensor-Actuator configuration To compensate for Lorentz force detuning during the 1 ms RF pulse Feed-Forward To counteract mechanical noise, “microphonics” Feed-Back Lutz Lilje DESY -MPY- 21.08.2018

Drawing of current setup (H.-B. Peters) Lutz Lilje DESY -MPY- 21.08.2018

RF signals at 35 MV/m Blue: With piezo Red: Without piezo Lutz Lilje DESY -MPY- 21.08.2018

RF pulse (500us fill, 800us flat-top) Piezo excitation of the cavity for frequency compensation (operation for 700 hours) RF pulse (500us fill, 800us flat-top) Lutz Lilje DESY -MPY- 21.08.2018

Single pulse compensation Pulse Parameters: frequency = 219 Hz time delay = 0.84 ms amplitude = 95V Lutz Lilje DESY -MPY- 21.08.2018

Single pulse compensation MICROPHONICS Lutz Lilje DESY -MPY- 21.08.2018

Damping of the ringing between pulses (5Hz operation) RF pulse RF pulse RF pulse Lutz Lilje DESY -MPY- 21.08.2018

Frequency stabilization during RF pulse using a piezoelectric tuner Blue: With piezo Red: Without piezo Frequency detuning of 500 Hz compensated voltage pulse (~100 V) on the piezo. No resonant compensation Frequency stabilization during RF pulse using a piezoelectric tuner Lutz Lilje DESY -MPY- 21.08.2018

Option: Resonant excitation of a mechanical cavity resonance if one excites a mechanical resonance of a cavity with the piezo, one can use the cavity as an mechanical amplifier, so that a small stroke of the active element can compensate large detuning we have shown that with the excitation of three periods of the mechanical resonance frequency, about 1000 Hz could be compensated Lutz Lilje DESY -MPY- 21.08.2018

Resonant excitation (stable for 200 hours) Pulse Parameters: frequency = 219 Hz time shift = -9.5 ms amplitude = 24V offset = 24V Lutz Lilje DESY -MPY- 21.08.2018

Resonant excitation Lutz Lilje DESY -MPY- 21.08.2018

Frequency stabilization at 35 MV/m Blue: With piezo Red: Without piezo Frequency detuning of ~1000 Hz compensated with resonant excitation of a mechanical cavity resonance at 230 Hz. NOTE: This is rather an demonstration of the capability of active tuning. Application in a real machine is probably difficult/ impossible. Needs investigation. Lutz Lilje DESY -MPY- 21.08.2018

Module Measurements Lutz Lilje DESY -MPY- 21.08.2018

Single Piezo - Single Pulse Compensation inside the module f=200Hz, only 100Hz compensation Lutz Lilje DESY -MPY- 21.08.2018

Single Piezo - Resonant Lutz Lilje DESY -MPY- 21.08.2018

Problems with the active tuner Fundamental problem: Preload at operating temperature not defined Large tuning needed for both cavities tested in CHECHIA (AC72, AC73) ´natural´ frequency after tank welding is 780 kHz above 1,3 GHz Normally this is more like 200-300 kHz This results in a very large force tearing on the piezo fixture Fixtures open up and piezos become loose Lutz Lilje DESY -MPY- 21.08.2018

Force Measurement at the Piezo Position Design by Karsten Gadow (H1) Available before end of the year Detailed measurement of the force in the cold environment Calibration will be first done to liquid nitrogen temperatures Then design a fixture with sufficient stiffness Lutz Lilje DESY -MPY- 21.08.2018

Problems with active tuning Single Piezo fixture So far only 100-200 Hz compensated (no resonant excitation of the cavity) Achieved compensation at 1,3 GHz Alternative: Resonant mechanical excitation of the cavity Double Piezo fixture Has only been operated at 1,3 GHz + 600kHz Needs a stiffer design Alternative: Put 2 single Piezo fixtures at different posts of the tuner Bipolar operation of Piezos helps in any case Check in CHECHIA and INFN Lutz Lilje DESY -MPY- 21.08.2018

Fixture twists during operation Fixture Twist Problem  Fixture twists during operation Lutz Lilje DESY -MPY- 21.08.2018

Problems with active tuning Automation is needed for operation of the piezos in the machine Determination of optimum pulse shape Interconnection to LLRF system Lutz Lilje DESY -MPY- 21.08.2018

Available piezos (1/2) EPCOS NOLIAC Piezo Mechanik Physical Instruments Lutz Lilje DESY -MPY- 21.08.2018

Available piezos (2/2) Mechanical Electrical Lutz Lilje DESY -MPY- 21.08.2018

Conclusion Proof-of-principle Engeneering is needed Single-piezo Non-resonant:100Hz in the module Resonant: 200 Hz in the module (We can use this in module 6!) Double-piezo Non-resonant: 400 Hz (not at 1.3GHz exact) Resonant: 1kHz Test of bipolar operation Engeneering is needed Choice of Piezo (-> together with INFN, IPN Orsay)) Stiffer Piezo fixture/frame for 2 Piezos Force measurement is underway (finished end 2004?) LLRF integration New Saclay tuner tests needed Available end 2004 / beginning 2005 Change of cavity pre-tuning desirable Conclusion Lutz Lilje DESY -MPY- 21.08.2018