STATUS OF THE MAIN BEAM QUADRUPOLE NANO-POSITIONING

+ SOME OBJECTIVES WITHIN PACMANK. Artoos , S. Janssens, C. Collette (ULB), M. Esposito, C. Eymin, P. Fernandez Carmona

K. Artoos , CLIC Workshop 2014

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Outline

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

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Ground motion mitigation

StabilisationAlignment

BPM Quad Fidu

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Compatibility of cascaded systems

BPM

(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

RangeAccuracy

Precision/resolution

Each system position should be unique above its resolution + known

Interaction ranges and accuracy Conditions precision and accuracy cascaded systems Conditions for > 6 d.o.f., Abbé errors + deformations

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Boundary conditions

Accelerator environmentHigh radiation Stray magnetic fieldLarge temperature variations

Stiffness-Robustness Applied forces (water cooling, vacuum, power leads, cabling, interconnects, ventilation, acoustic pressure)

-Transportability/Installation

Available spaceIntegration in two beam module620 mm beam height

Stiff actuating systemK> 100 N/μm vertical+lateral

Longitudinal transport lockingSuccessfully tested with x-y prototype

Ok, type 1 was not easy

No manpower

Tests in 2014

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Concept for MBQ

• 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

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Concept for MBQ

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

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Concept for MBQ

Central fixed partMagnet mounted with assembly tool

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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

201 Hz

140 Hz122 Hz

241 Hz

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X-y positioning: Study precision, accuracy and resolution

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Comparison sensors

Sensor Resolution Main + Main -

Actuator sensor 0.15 nm No separate assembly

ResolutionNo direct measurement of magnet movement

Capacitive gauge 0.10 nm Gauge radiation hard Mounting tolerancesGain change w. Orthogonal coupling

Interferometer 10 pm Accuracy at freq.> 10 Hz

CostMounting toleranceSensitive to air flowOrthogonal coupling

Optical ruler 0.5*-1 nm Cost1% orthogonal couplingMounting toleranceSmall temperature driftPossible absolute sensor

Rad hardness sensor head not knownLimited velocity displacements

Seismometer (after integration)

< pm at higher frequencies

For cross calibration

K.Artoos, Stabilisation WG , 21th February 2013

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Displacement sensors

+ actuator gauges, interferometer + seismometers (calibration)

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First measurementsMeasured 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

EUCARDdeliverable

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2014

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

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Nano positioning sensors

Heidenhain : 1nm resolution < 1000 CHFRenishaw: 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

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Integrated luminosity simulations

No stabilization 68% luminosity lossSeismometer 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 2013Stef Janssens

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Resolution limitationsSensors

Stabilisation

Limitations:1. Thermal stability

(*alignment)2. EM stray fields3. Sensor resolution

(wavelength light)Expected maximum one order of magnitude improvement resolution in next decade (Without major technological innovation) Low freq. is where you can win the most

Michelson Stabilised LASER

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Nano positioning

« Nano-positioning» feasibility studyModify 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

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X-y Positioning: roll

1&2Parasitic 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)

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Roll simulations

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Mass/Actuator Resolution/ Range/k/ Bandwidth

𝑓 0 (𝜔 )=√𝑘𝑎𝑐𝑡𝑢𝑎𝑡𝑜𝑟

𝑚𝑙𝑜𝑎𝑑

Stress < depolarisation stressA For same Range: P

A

Bandwidth is limited by

Remark about load compensating springs:

• Actuator slew rate

Frequency

Am

plit

ude

Range

Force

Load compensation reduces range + bandwidthImproves resolution *