STATUS OF THE MAIN BEAM QUADRUPOLE NANO-POSITIONING + SOME - - PowerPoint PPT Presentation

STATUS OF THE MAIN BEAM QUADRUPOLE NANO-POSITIONING + SOME OBJECTIVES WITHIN PACMAN

• K. Artoos , S. Janssens, C. Collette (ULB), M. Esposito,
• C. Eymin, P. Fernandez Carmona
• K. Artoos , CLIC Workshop 2014

Outline

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 Intro + Link to the PACMAN project  Design + Construction of the type 1 stabilisation

system

 First measurements  2014

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Possible mitigation techniques:

• Alignment
• B.P.M. + dipole correctors
• B.P.M. + Nano positioning
• Seismometers + Dipole correctors
• Mechanical stabilization with seismometers

f

Ground motion mitigation

Stabilisation Alignment BPM Quad Fidu

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Compatibility of cascaded systems

B P M (m) 10-2 10-3 10-4 10-5 10-6 10-7 10-8 10-9 10-10

Alignment

• Magn. Fidu.

BPM Nanopos.

Stabilisation

Range Accuracy Precision/resolution



Each system position should be unique above its resolution + known

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Interaction ranges and accuracy



Conditions precision and accuracy cascaded systems



Conditions for > 6 d.o.f., Abbé errors + deformations

Boundary conditions

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Accelerator environment High radiation Stray magnetic field Large temperature variations Stiffness-Robustness Applied forces (water cooling, vacuum,

power leads, cabling, interconnects, ventilation, acoustic pressure)

• Transportability/Installation

Available space Integration in two beam module 620 mm beam height

Stiff actuating system K> 100 N/μm vertical+lateral Longitudinal transport locking Successfully tested with x-y prototype Ok, type 1 was not easy No manpower Tests in 2014

Concept for MBQ

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• Inclined stiff piezo actuator pairs with flexural

hinges (vertical + lateral motion) (four linked bars system)

• X-y flexural guide to block roll + longitudinal

d.o.f.+ increased lateral stiffness.

Flexural pins

Concept for MBQ

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A stiff but light Fixed frame around the mobile part, objective Natural frequencies > 100 Hz

Concept for MBQ

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Central fixed part Magnet mounted with assembly tool

Concept for MBQ

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Concept for MBQ

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Concept for MBQ

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Modal analysis Type 1 (simulation) soon to be tested

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201 Hz 140 Hz 122 Hz 241 Hz

X-y positioning: Study precision, accuracy and resolution

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Comparison sensors

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Sensor Resolution Main + Main - Actuator sensor 0.15 nm No separate assembly Resolution No direct measurement

• f magnet movement

Capacitive gauge 0.10 nm Gauge radiation hard Mounting tolerances Gain change w.  Orthogonal coupling Interferometer 10 pm Accuracy at freq.> 10 Hz Cost Mounting tolerance Sensitive to air flow Orthogonal coupling Optical ruler 0.5*-1 nm Cost 1% orthogonal coupling Mounting tolerance Small temperature drift Possible absolute sensor Rad hardness sensor head not known Limited velocity displacements

Seismometer (after integration) < pm at higher frequencies For cross calibration

K.Artoos, Stabilisation WG , 21th February 2013

Displacement sensors

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+ actuator gauges, interferometer + seismometers (calibration)

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First measurements

Measured still on the assembly bench, not on the floor….

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First measurements

• (Noisy, especially

laterally)

• Good precision
• Calibration is needed for

a better accuracy

Horizontal motion: (with gain correction for roll)

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First measurements

Testing of the range

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Type 1 Collocated pair X-y proto Seismometer FB max. gain +FF (FBFFV1mod): 7 % luminosity loss (no stabilisation 68 % loss)

Concept demonstration actuator support with staged test benches

EUCARD deliverable

2014

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 Assemble type 4, all parts ready (- assembly tool)  T1 + T4 : combine stabilisation and alignment  Extensive testing stabilisation, nano positioning + in

• combination. First “PACMAN tests”.

 Sensor out sourcing + testing  Study alternatives for BDS

actuating systems (decrease roll)

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Spare slides

Nano positioning sensors

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Heidenhain : 1nm resolution < 1000 CHF Renishaw: 1 nm resolution < 1000 CHF Smallest LSB can be used as quadrature …. 0.1 nm resolution is already possible Technological innovation: ABSOLUTE optical encoders Faster measurements

Integrated luminosity simulations

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No stabilization 68% luminosity loss Seismometer FB maximum gain (V1) 13% Seismometer FB medium gain (V1mod) 6% (reduced peaks @ 0.1 and 75 Hz)

• Seis. FB max. gain +FF (FBFFV1mod) 7%

Inertial ref. mass 1 Hz (V3mod) 11% Inertial ref. mass 1 Hz + HP filter (V3) 3% Courtesy J. Snuverink, J. Pfingstner et al.

Commercial Seismometer Custom Inertial Reference mass K.Artoos, Stabilisation WG , 21th February 2013

Stef Janssens

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Resolution limitations Sensors

Stabilisation Limitations:

• 1. Thermal stability

(*alignment)

• 2. EM stray fields
• 3. Sensor resolution

(wavelength light)

Expected maximum one

• rder of magnitude

improvement resolution in next decade (Without major technological innovation) Low freq. is where you can win the most

Michelson Stabilised LASER

Nano positioning

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« Nano-positioning» feasibility study

Modify position quadrupole in between pulses (~ 5 ms) Range ± 5 μm, increments 10 to 50 nm, precision ± 0.25 nm

• Lateral and vertical
• In addition/ alternative dipole correctors
• Use to increase time to next realignment with cams

X-y Positioning: roll

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1&2 Parasitic roll

• S. Janssens, CLIC Workshop, January 2013
• 2 legs 3 d.o.f. > parasitic roll
• Measured with 3-beam interferometer
• ~3 μm lateral movement > ~7 μrad rotation
• Early simulations suggest~100 μrad/0.5%

luminosity loss (J. Pfingstner)

Roll simulations

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Mass/Actuator Resolution/ Range/k/ Bandwidth

• 𝑔

0 𝜕 = 𝑙𝑏𝑑𝑢𝑣𝑏𝑢𝑝𝑠 𝑛𝑚𝑝𝑏𝑒

Stress < depolarisation stress A↑ 𝑊𝑝𝑚𝑣𝑛𝑓 ↑ 𝐷𝑞𝑨𝑢 ↑ For same Range: P↑ Resolution ↓ A Bandwidth is limited by Remark about load compensating springs:

• Actuator slew rate

Frequency Amplitude Range Force Load compensation reduces range + bandwidth Improves resolution *