The Virgo+ shutdown

1 ILIAS Birmingham, 10/07/2008H. Heit mann

The Virgo+ shutdownThe Virgo+ shutdown


Performances before V+ shutdownPerformances before V+ shutdown


Virgo progressVirgo progress


Virgo sensitivity: May 2008Virgo sensitivity: May 2008

Spikes: relaxation of magnet waterglass glueing


Recent upgradesRecent upgrades


The cryotrapThe cryotrap

Brewster window (SR-DT) introduces noise Several attempts to mitigate scattered light

Baffles in detection and SR towers, near the Brewster, …

Final decision: remove it Avoid spoiling of central area vacuum from detection tower=> cryotrap

Cryotrap installation shutdown 10 days

Interferometer locked immediately afterwardsNice success of the vacuum group

Detectiontower

Signal recycling

To e

xt.

dete

ctio

n b

ench


Cryotrap functioningCryotrap functioning

Duration of functioning 3 days

Refilling takes 1 hour

Project of increasing functioning time to >= 1 weekBefore the next science run


DAQ room air conditioning upgradeDAQ room air conditioning upgrade

Air conditioning systems affects the Virgo sensitivity

DAQ room is just in front of the detection lab the noise of its (oldest) air conditioning system has been found

directly in the dark fringe

AC ONAC OFF

Central hall AC Water pump of CECleanRooms AC Laser lab

DAQ room (+CE hall)

North End AC


DAQ room air conditioning upgradeDAQ room air conditioning upgrade

Acoustic isolation of the DAQ

=> reduce noise in central area

430

UTA

120

200

70

32

90

60 232.5

119

301

137.5

157

233.

5

AC

SR DT DT lab

New AC system outside DAQ

Microphone sees a noise reduction wrt. to the previous situation.

beforeafterAC offHz


Thermal compensation systemThermal compensation system

Thermal lensing in the input mirrors has had a strong impact on commissioning

Complicated locking procedure for surviving thermal transientBistabilities arise during transitionBe sure to catch the good state for continuing locking

We want to go from 8 to 25 Watt in Virgo+Much higher power => no hope to survive thermal deformations

=> Thermal compensation system neededCO2 laser ring system designed and realized by Roma Tor Vergata

group with support by EGO


TCS layoutTCS layout

Electronics

Chiller


L4

2" Hot mirrorL2M

AXICON

L1

L8L7

LASY-20S

Aiming laser

Beam splitter

Beam splitter

Power meter

Polarizer

Half waveplate

Beam dump

AOM

TCS optical layoutTCS optical layout


TCS in-vacuum opticsTCS in-vacuum optics

In vacuum steering mirrors needed


TCS in-vacuum opticsTCS in-vacuum optics

In vacuum steering mirrors needed


TCS statusTCS status

CO2 laser problemsOne of the two lasers arrived broken from the company (Access Laser)Sent back but delivered again out of order

Probably an undetected CO2 gas leakageSent back to the company a second time

WI TCS commissioning startedStill many things to be learned, but:First encouraging results (see Enrico’s talk)

To be donePower stabilization to be realized in the next monthsCentral spot needed for reducing thermal transient time?Continue commissioning as soon as interferometer available again


The Eddy current issueThe Eddy current issue

Increase of thermal noise due to Eddy current dissipationToo strong SmCb magnets + aluminum reference massNoise level <-> Virgo sensitivity: subject to discussions

Magnetic noise coupling from external perturbations

Solution 1Ferromagnetic hats proposed for reducing magnetic field

Solution 2 (chosen)In-place substitution of magnets with smaller onesEndoscopic procedure with tube, vacuum aspiration of dust etc.Worked well, except re-gluing of one FS support with “water glass”=> glitches in WI?

NE magnet substitution =>

No more Eddy current problems expected in Virgo+


Upgrades during the Virgo+ Upgrades during the Virgo+ shutdownshutdown


Virgo+ shutdownVirgo+ shutdown

Was scheduled for 3rd of JuneMay 9th incident => shutdown anticipated by 3 weeksRequired rearrangement of infrastructure works due to need of

clean rooms

Shutdown: Virgo+ packagesHigh power laser + corresponding opticsNew control and DAQ electronicsEnvironmental noise mitigationNE tower recovery


Laser amplifier ILaser amplifier I

Amplifies 20 W slave laser => 50 (up to 65) WIntegration started 22/05

Old Virgo layout

This part has been removed


Laser amplifier IILaser amplifier II

Much denser optical setup


Pre Mode CleanerPre Mode Cleaner

PMC was designed for filtering of technical laser noise at 6 MHzAlso guarantees a good beam shape


mirror

piezoCorundum ½ sphere

SpiderZeroduractuator

Brewster window

Front mirrors

Vacuum tank

0.35m

- Triangular zerodur cavity * avoid thermal control - low mechanical Q

- Controlled by 1 piezo* Corundum half sphere glued on piezo * Pushing a “telescope spider” shaped support* 6x12 diam. mirror, glued on spider-> Avoid piezo bending transfer to mirror displacement)( simulation by F. Richard)

- Vacuum tank, Brewster window

126m

m

74mm

Glued mirrors

Mirror glued on piezo

PMC mechanical schemePMC mechanical scheme


PMC on its cradle

PMC tank

PMC mountingPMC mounting


External injection benchExternal injection bench

Super-polished optics for avoiding scattered lightPolished by General Optics / coated by LMA, Lyon

From laser

To ITF


Suspended injection benchSuspended injection bench

Faraday isolation factor will go down with higher power (therm. lens)=> insertion of remotely controllable waveplate for isolation improvement+ compensation plate, if necessary


Input mode cleaner mirrorInput mode cleaner mirrorOld MC mirror was not good

Too light (80x30 mm)radiation

pressure forces

reference mass suspension <-> coil cables

Bad optical quality;backscattering in opposite

direction


New MC payloadNew MC payload

New MC mirror payloadHeavier (1.4 kg)Better optical quality


Control and DAQ Electronics packageControl and DAQ Electronics package

Big change in electronics during shutdownObsolete componentsBetter design (differential ADC inputs,…), lower noiseBetter performance (global control speed, more filters,…)

1. DAQ electronics (LAPP, Annecy)Real time PCs, interconnected with Mux/Demux boardsNew ADCs, timing systemInstallation ongoing; to be finished during shutdown

2. New DSP for suspension control (Pisa)Much more powerful (6 DSP on one chip)

Step-by-step installation, in parallel with old systemInstall new DAQ system

check that new data is same as old oneInstall new global control system

check that new Gc output is the same as old oneCheck compatibility of new system with suspension control (DSP)

=> when all tests positive, go to new system


Suspension controlSuspension control

STAC/Council June 2008 29

Computing Room

Mx/

Dx

RIO

-B

DSP

Sc

DSP

Sa

ADC

PSD

Platform

RT P

C

RIO

-A

Mx/

Mx

Mx/

Dx

DSP

Sa

DSP

Sc

RIO

-B

ADC

PSD

RT P

C

RIO

-A

Mx/

Dx

DSP

Sa

DSP

Sc

RIO

-B

ADC

PSD

RT P

C

RIO

-A

Mx/

Dx

DSP

Sa

DSP

Sc

RIO

-B

ADC

PSD

RT P

C

RIO

-A

Mx/

Dx

DSP

Sa

DSP

Sc

RIO

-B

ADC

PSD

RT P

C

RIO

-A

Cam

era

Cam

era

Cam

era

Cam

era

Cam

era

DAC

s

DAC

sD

ACs

DAC

sD

ACs

AD

Cs

AD

Cs A

DCs

AD

Cs A

DCs

Mx/

Dx


ISYS controlISYS control


Computing Room

Mx/

Dx

RIO

-B

DSP

Sc

DSP

Sa

ADC

Coil

ADC

PSD

Platform

RT P

C

RIO

-A

ADC Env,Qt

ADC

SSFS

,IMC

ADC

RFC,

BMS

RIO

-A L

o:Vb

:Qa

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C Ca

RTRT

PC

ISYS

RT PC DETM

x/D

x

Mx/

Dx

Mx/

Dx

Mx/

Dx

DSP

Sa

DSP

Sc

RIO

-B

ADC

PSD

ADC

Coil

RT P

C

RIO

-A

Cam

era

RIO-A

DSP Bc

BMS

DACCam

era

DAC

s

DAC

s

DAC

AD

Cs

AD

Cs


ITF controlITF control


Computing Room

Mx/

Dx

RIO

-B

DSP

Sc

DSP

Sa

ADC

Coil

ADC

PSD

Platform

RT P

C

RIO

-A

Mx/Dx

RIO

-A L

o:Vb

:Qa

RIO

-B B

7Pos

ADC

B7AD

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7

ADC Env,Qt

ADC

B2,B

2_3f

ADC

SSFS

,IMC

ADC

RFC,

BMS

RIO

-A L

o:Vb

:Qa

ADC

PiAD

C M

c

ADC

B1,B

1pAD

C B1

_2f,B

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C B5

,B5_

2fRT

PC

CaRT

RT P

C IS

YS

RT P

C tx

,tyIT

FRT

PC

zITF

RT PC DETM

x/D

x

Mx/

Dx

Mx/

Dx

Mx/

Dx

Mx/

Dx

Mx/

Dx

DSP

Sa

DSP

Sc

RIO

-B

ADC

PSD

ADC

Coil

RT P

C

RIO

-A

Mx/

Dx

DSP

Sa

DSP

Sc

RIO

-B

ADC

PSD

ADC

Coil

RT P

C

RIO

-A

Mx/

Dx

DSP

Sa

DSP

Sc

RIO

-B

ADC

PSD

ADC

Coil

RT P

C

RIO

-A

Mx/

Dx

DSP

Sa

DSP

Sc

RIO

-B

ADC

PSD

ADC

Coil

RT P

C

RIO

-A

ADC

Q5

ADC

Q2

ADC

Q1p

RIO-ACalibration

ADC Mx/Dx

Cam

era

Cam

era

Cam

era

Cam

era

RIO-A

DSP Bc

BMS

DACCam

era

DAC

s

DAC

sD

ACs

DAC

sD

ACs

DAC

DAC

2 Ca

mer

as

2 D

ACs

RIO

-B1*

,B5

Pos

4 Ca

mer

as

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4 D

ACs

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a2

DAC

s

AD

Cs

AD

Cs A

DCs

AD

Cs A

DCs

ADC

SFP,

TCS

ADC

Ph.C

am


Environmental noise reductionEnvironmental noise reduction

The reduction of the environmental noises is a “never ending story”

During the shutdown a series of tests and actions is going on

The major ones arethe displacement of the laser lab electronics to a new “EE room”the displacement of the detection photodiodes under vacuum


The EE (electronics equipment) roomThe EE (electronics equipment) room

A part of the laser lab electronics racks will go to its own roomAcoustically isolatedLaser chiller has a separate room

Laser lab

EE room

MC


Photodiodes under vacuumPhotodiodes under vacuum

34

• Photodiodes, the pre-amplifier, the motors and supports will go under two vacuum proof boxes, air filled (electronics cooling)

Putting photodiodes under vacuum for reducing environmental noise coupling through scattered light


The boxesThe boxesBoxes are in steel (3mm thick) and their behavior in vacuum has been

FEM studied at LAPP.

The additional weight should be compliant with a minor retuning of the suspension


Summary – upgrades already madeSummary – upgrades already made

Cryotrap installationFor getting rid of “Radio Brewster”

DAQ room airconditioning improvementFor reducing environmental noise

Thermal compensation system Installed, but laser broken; to be commissioned

Magnet weakeningResults to be seen after restart


Summary - Virgo+ shutdown upgradesSummary - Virgo+ shutdown upgrades

Injection system opticsLaser amplifier – installed, long term observation going onPre-Mode cleaner – installed, lockedLow scattering optics on ext. bench - optics deliveredFaraday isolation, remote tuning - to be installed

Mode cleaner curved mirror with marionette+reference massInstalled: MC has been relocked

Laser lab electronics equipment roomInfrastructure works finished; electronics to be migrated

Photodiodes under vacuumTo be installed after whole ITF has been relocked again

New DAQ electronicsOngoing; to be finished before relock

New suspension electronicsTo be done in a second time

End


Cryotrap: Residual gas analysisCryotrap: Residual gas analysisRGA installed on trap (SR side) Before (blue) and after (black) the DT opening, and compared to DT (blue)

air

H2

water

Contamination 1E-10 mbar

Part. pressure (mbar)

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The Virgo+ shutdown

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