MONALISA update

Tue 22 Sept 2009Stabilization Day 7Oxford MONALISA

1

MONALISA updateCould the messenger of bad

vibration news be the cause of it?

beam pipe

Shintake interference patter

Seismic Sensors


2

Overview

• Goal of ATF2 installation: Test if MONALISA vacuum system introduces vibrations onto Shintake monitor

• Installation of MONALISA vacuum system at ATF2

• Minimal Force system• Motion Stability during pump down measured by

KEK survey team

• Vibration Measurements of LAPP group • Fringe stability test done by Shintake

group (Tokyo University)


3

Good progress• We kept within our proposed schedule

– As set out in ATF2 meeting 17 Jun 09

• All items arrived at KEK 1st July 2009– Brought to ATF2 roof within 15 mins of arrival

• On ATF2 roof– System assembled and retested

• Brought to ATF2 Final focus tunnel – Reassembled at IP Thursday 9th July and

tested


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On the roof of the ATF2


5

Schematic Layout of Pneumatics • Vacuum in end boxes connected through inner bellows• High pressure only connected to outer bellows chamber


6

Sensor readout during pumping


7

Into the ATF2 tunnel


8

The DBS was hoisted into placeFull assembly completed well

within one day


9

DBS pumped out: with rods in

• Reached 28 Pa with a different pump– vacuum integrity was unaltered


10

Tilt sensor• Tilt change on Shintake ~5+5 rad

– After MONALISA DBS installed at IP


11

Forces measured pumping down when mounted at ATF2 IP

Regulator cycle ~225 s


12

(x,y,z) Physicists coordinates• In the following we’re using the physicists

coordinate frame

Y

X

Z


13

Tracking QD0 motion in Z• Set MONALISA at operational pressure

– Pumped out vacuum vessel– Over-pressure in outer bellowed chamber

• Set up independent tracking of QD0– Used FARO to survey QD0 position changes– Keyence laser meter tracked QD0 mounted

on SD0 base plate


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KEYENCE tracking QD0 Z

Readout sensor in mV

10 V = 5 mm

1 mV = 0.5 m

Readout with ourADC/LabVIEW DAQ

QD0

Supported from SD0

KEYENCE


15

FARO survey instrument

FARO

Retro


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Comparison of FARO & KEYENCE


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Tracking QD0 motion in Z


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Tracking QD0 motion in X


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Left-right QD0 mover tests


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DBS spring constant is small enough to let QD0 move freely


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What to learn from this measurements?

• We are told that static tolerances for QD0:– 100μm in x,y,z

• Our measurements show that even with the current pressure control system we meet this tolerance.

• The low spring constant of the DBS allows the QD0 mover to move the magnet unhindered.

• Dynamic tolerances: vertical: 10 nm, (between Shintake and QD0) horizontal: 500 nm

along beam: 10 μm


23

Vibration Measurementsperformed by Benoît BOLZON (LAPP)

taken from talk presented at ATF2 meeting July 15.

1. Relative motion calculation using representative absolute motion

2. Impact of Monalisa on vibrations (3 directions) between: - Shintake and QD0 with and without pressure - QD0 and QF1 with pressure Comparison of measurements with/without Monalisa Measurements without MONALISA have been repeated two weeks ago with cooling water flowing inside FD

3. Conclusion


24

Choice of a representative ground motion measured at ATF2 Choice of a high ground motion during shift period

Friday 12/12/08 at 3pm Above 0.2Hz: 218nm Above 1Hz: 128nm

Amplitude almost the same during 4 hours of shift

Choice of ground motion at 3pm representative

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Relative motion calculation by taking this ground motion PSDgm


2525

• Impact of Monalisa on vibrations between: - Shintake and QD0 with and without pressure - QD0 and QF1 with pressure Comparison of measurements with/without Monalisa

Vibration measurements between Shintake and QD0

Vibration measurements between QD0 and QF1


2626

Vibration transmission between Shintake and QD0

Vertical direction

Almost same coherence: - With/without Monalisa - With/without pressure

Only difference: QD0 resonance slightly lower due to Monalisa weight

- No Monalisa: 65.3Hz - With Monalisa: 60.3Hz

With Monalisa: Same transfer function with/without pressure


2727


Vertical direction

Below 4Hz: increase of relative motion due to not enough high SNR(coherence very close to 1: relative motion should not increase)

Relative motion above 4Hz (should be the same than above 0.1Hz) :

Relative motion above 4Hz: - No Monalisa: 5.0nm - Monalisa with pressure: 5.7nm - Monalisa without pressure: 5.8nm

Almost no change compared to tolerances


2828


Direction parallel to the beam


Only difference: QD0 resonance slightly lower due to Monalisa weight




2929



Same relative motion with/without Monalisa (even better with Monalisa above 7Hz) Same relative motion with/without pressure in Monalisa


3030


Direction perpendicular to the beam


QD0 resonance almost the same:



SM resonance higher with Monalisa (59.6Hz 55.0Hz): good!


3131



Same relative motion with/without pressure in Monalisa

Same relative motion with/without Monalisa (even better with Monalisa above 10Hz)


3232

Vibration transmission between QD0 and QF1

Vertical direction

With Monalisa: QD0 and QF1 resonances slightly appear (factor 5) since QD0 resonant frequency is slightly lower (due to Monalisa weight)

Without Monalisa: QD0/QF1 resonances almost do not appear (very thin peak) since:

their frequencies are almost the same QD0/QF1 move in phase (very close to each other)


3333


Relative motion increase of 2nm with Monalisa due to QD0/QF1 resonances (decrease of QD0 resonant frequency) : very low! Solution: put a mass on QF1 to decrease its resonant frequency down to QD0 resonant frequency

Vertical direction


3434

With GM/flowing cooling water, relative motion of SM to QD0: Tolerance Without

MonalisaWith Monalisa(with/no Press)

Vertical 7 nm 5.0nm 5.7nm/5.8nm

Perpendicular to beam ~ 500 nm 16.7nm 16.7nm

Parallel to the beam ~ 10,000 nm 17.2nm 17.2nm

Tolerances still achieved with Monalisa (almost no influence) N.B: No influence of the regulation system With GM/flowing cooling water, relative motion of QF1 to QD0:

Without Monalisa

With Monalisaand pressure

Vertical 5.0nm 7.0nmPerpendicular to the beam

8.9nm 34.2nm

Parallel to beam 10.9nm 26.2nm In vertical direction: almost no influence of Monalisa In horizontal directions: still acceptable because of the large tolerances A solution: put a mass on QF1 to get same resonances than QD0 ones

This is not an issue!!


35

Phase StabilityTaken from the talk presented by

T. Yamanaka at ATF2 meeting 15 July 09

• Motivation– Shintake monitor uses laser interference fringe

pattern to measure beam size.– It is important to know the stability of the fringe

position ( = fringe phase).– However, it is impossible to measure it at the IP

Measure fringe phase stability indirectly off the IPand get the information about the IP fringe


36

Phase Stability Measurement

Microscope Lens

Linear Image Sensor

Measure fringe profile

Fourier transform and get the peak frequency

Calculate the phase at the peak frequency

Make interference fringe again on the lens and Magnify

IP

Schematic of Phase Monitor


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Measurement for MONALISA

• Phase stability is the key of the Shintake monitor• Checked the effect of the MONALISA system

1. without MONALISA

2. MONALISA is mounted on the Shintake monitor table and QD0, double bellows system is activated

3. MONALISA is mounted, the MONALISA chamber is opened to atmosphere

• All the measurements were performed in the midnight.


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Without MONALISA

1 min phase stability (RMS)Long term time variation of the phase

Histogram of 1 min phase stability

Mean: 135 mradRMS: 52 mrad


39

MONALISA Mounted, Double Bellows System Activated





40

MONALISA Mounted,Atmospheric Pressure



Mean: 153mradRMS: 39 mrad


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Summary

• 1 min phase stabilityCondition Mean [mrad] RMS [mrad]

without MONALISA 135 52

MONALISA, Activated 163 49

MONALISA, Atmospheric Presssure

153 39

• It seems to be a little bit worse when MONALISA is mounted.• It seems to be a little bit worse when the double bellows system is activated.• However, there exists not a little time variation of the phase stability so it can be say MONALISA system doesn’t influence the fringe phase stability so much.

Ref. ) 135 mrad and 163 mrad phase stability corresponds to 5.7 nm and 6.9 nm fringe position stability in 174 degree crossing angle mode.


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So what do we learn from this

• The messenger of the news is not affecting its message:– We do not cause undue vibrations.

• The double bellow system produces very small forces

• Care is required when using a vacuum system


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Vacuum System

8 way fibre ribbon

Tapered hole

Vacuum vessel wall


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Summary & Outlook

• MONALISA vacuum system worked well– Many thanks for the wonderful support we got!

• The next step is to do optics tests with the vacuum system in place to gain calibration constants.

• Our goal is to get first position measurements to the Shintake group next spring/summer.


46

Implications for MONALISA at CLIC

• Important to be prepared if vacuum system should be needed– Idea mount a flange on the bottom of the magnet– This flange will hold retros– This flange can be used to attach a future vacuum

system• We probably need a force neutralizing double

bellows system as well, since the magnet is on movers.– Nee big enough a hole through the support structure

to allow a double bellow system– Integration


47

Non-vacuum system

• The following systems are (almost) ready– Lasers that can be brought to CERN– Readout including Crate, amplifiers, ADCs

• We are currently designing the interferometer heads that we wish to bring to KEK. We can easily build a few additional heads for CERN, although the idea is of course to further develop and adapt the heads to the CLIC specific needs

• We need to tackle things like placement of laser/readout with respect to the magnet to address laser safety, purchase fibres....


48

Forces on frame during pumping

• Cycled bellow chamber pressures– Inner chamber 100 kPa to 25 Pa to 100 kPa– Outer chamber 100 kPa to 140 kPa to 100kPa

• Measured forces– Using recalibrated force sensor

• Independently calculated forces– Based on SMC pressure sensors

• One for each chamber


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Tunnel preparation

Terunua-san installed pipe across the inside of the ATF2 final focus tunnel roof

Equipped with 2 hoists


50

Mounting Shintake components• Plate mounted using M30 hooks

• End box mounted using hoist

Cables


51

Mounting QD0 end box• Beeswax was placed on QD0 surface

– To ensure good vibration coupling to magnet


52

End boxes mutually aligned

• Laser light projected along accelerator axis

• Shintake end box – (left-right adjustable)– Moved to match QD0

end box


53

FARO compared with KEYENCE


54

FARO tracking X and Z


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Over-pressure regulation• Over-pressure regulator does not behave

as we would like

Control Signal /V

Overpressure / kPa

0

40

Vmax0

No response for over-pressure requests less than (50 mbar)


56

Required over-pressure regulation• Would want a straight line relationship

even for very low over-pressure

Control Signal /V

Overpressure / kPa

0

40

Vmax0


5757


Vertical direction

No pressure

Transfer function measurements done during 4 hours the night (quiet) Frequency resolution: 0.016Hz Time resolution: 19 minutes

Pressure

Tim

e

Frequency

Am

plit

ude

Frequency

Am

plit

ude

Tim

e

Vibration measurements (with pressure in Monalisa) done simultaneously with frange measurements of SM

Same transfer function (with and without pressure) over time


5858



With Monalisa: QD0/QF1 resonances slightly appear (factors 5) since QD0 resonant frequency is slightly lower (due to Monalisa weight)

Without Monalisa: QD0/QF1 resonances almost do not appear (factors 2/3) since:



5959



Relative motion increase of 15nm with Monalisa due to QD0/QF1 resonant frequencies Very low increase compared to tolerances (500nm)


6060



With Monalisa: QD0/QF1 resonances slightly appear (factors 5 and 3) since QD0 resonant frequency is slightly lower (due to Monalisa weight)

Without Monalisa: QD0/QF1 resonances almost do not appear (factor 2) since:



6161



Relative motion increase of 25nm with Monalisa due to QD0/QF1 resonant frequencies Very low increase compared to tolerances (500nm)


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Backup


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Remark

• 1 minute is an assumed one beam size measurement time with the Shintake monitor.

• 2π [rad] phase corresponds to one period of the interference fringe pitch

crossing angle [deg] fringe pictch [μm] 100 mrad phase stability [μm]

2 15 0.24

8 3.8 0.061

30 1.0 0.016

174 0.27 0.0042


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Measurement in Last Year

Measurement in summer of last year


Last year This year

Laser repetition frequency

10 Hz 6.25 Hz

Measurement frequency

10 Hz 1.5625 Hz

Laser output power Low Maximum

Laser and chiller location

side of the optical table

Laser room outside of the shield

Difference between last year and this year measurement

Documents

MONALISA update