BSC CLEAN ROOM PROCEDURES Riccardo DeSalvo
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LIGO-G060130-00-R BSC CLEAN ROOM PROCEDURES Riccardo DeSalvo • These notes are based in part on Input and experience from LMA-Lyon • The lesson learned are applied to the LIGO BSC chambers that house by far the most sensitive mirrors
description
These notes are based in part on Input and experience from LMA-Lyon The lesson learned are applied to the LIGO BSC chambers that house by far the most sensitive mirrors. BSC CLEAN ROOM PROCEDURES Riccardo DeSalvo. The ITM and BS of the 2k have been contaminated, - PowerPoint PPT Presentation
Transcript of BSC CLEAN ROOM PROCEDURES Riccardo DeSalvo
LIGO-G060130-00-R
BSC CLEAN ROOM PROCEDURES
Riccardo DeSalvo
• These notes are based in part on Input and experience from LMA-Lyon
• The lesson learned are applied to the LIGO BSC chambers that house by far the most sensitive mirrors
LIGO-G060130-00-R
Cleaner mirror installation for Ad-LIGO
• The ITM and BS of the 2k have been contaminated, showed anomalous absorption and thermal lensing.
• This contaminant was easy to remove (drag-wipe)• The contaminant turned out being particles, possibly
soot, that entered the BSC during maintenance.• Ad-LIGO will be >>10 times more sensitive to thermal
lensing effects• Need to establish better defense against contaminants
See also T050068-00-R
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Cleaner mirror installation for Ad-LIGO
• Strippable paints, suggesting by Helena are a good start
• The main contaminant though, may be the operator that strips the paint and later performs the alignment
• Need an additional defense line• Laminar flow clean chamber is the
answer
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SCHEME OF A CLEAN ROOMSCHEME OF A CLEAN ROOM
Filtres
Air Propre
+ Flux
Laminaire
Laminar flow Screen
Clean Air
+ LaminarFlow
Absolute Filtres99,999 %
FANSRecycle
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Laminar Flow Turbulent Flow
Particles
The particles, are dragged away by the flow before they can diffuse on the
optics.Low polluting probability
The turbulent flow actually helps diffusing the particles
from the source to the optics High polluting probability.
Importance of air flow regimeImportance of air flow regimeImportance of air flow regimeImportance of air flow regime
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CORRECT MANIPULATIONCORRECT MANIPULATION
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INCORRECT MANIPULATIONINCORRECT MANIPULATION
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Nombre de particules
InitialAprès 48 H sous flux turbulent"équivallent " Classe 100
Flux Turbulent « équivalant » Classe 100
Many large particlesMany large particles
Particle count on silicium waferParticle count on silicium waferParticle count on silicium waferParticle count on silicium wafer
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Flux Laminaire Classe 10
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InitialAprès 48 H sous flux laminaireClasse 10
small significative small significative changechange
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LIGO-G060130-00-R
the CLEAN ROOM WE NEED TO ESTABLISHthe CLEAN ROOM WE NEED TO ESTABLISH
Filtres
Air Propre
+ Flux
Laminaire
Laminar flow Screen
Clean Air
+ LaminarFlow
Absolute Filtres99,999 %
FANSRecycle
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BSC Volume and flow parametersBSC Volume and flow parametersBSC Volume and flow parametersBSC Volume and flow parameters
BSC cross section
Maximum
Laminar air speedFlow
6 m2 0,45 m/s ~ 3 m3/s
BSC heightReplacement
timeReplacement rate
~3 m ~1.5 s 2400 vol/hour
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How to implement laminar flowClean room facilitiesIn the BSC chambers
Pressurize optical benchUse threaded and additional holes as
laminar flow diffusersCollect the clean air with a sieved
floor
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Air inletGate valve
Drive bellow
Seismically isolatedOptical bench
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2.0 m3/s For annular
LaminarFlow
Curtain
1.0 m3/s For core ~laminar
flow
2.8m3/sSuction
7-8% outflow
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Laminar Flow curtains
Particles
The particles, are dragged away by the flow before they can diffuse in the turbulent flow
volume.But high turbulence induced in the optics region
can still generate particulate contaminationDiminished but not negligible polluting probability
Importance of air flow regimeImportance of air flow regimeImportance of air flow regimeImportance of air flow regime
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Laminar Flow curtains plussemi-laminar flow core
Particles
The suspension mechanics disturbs the otherwise laminar flow. Particles from outside are screened off by the laminar
flow curtain. Particles injected by the operator in the semi-laminar volume are still dragged away by the flow although
less effectively.Minimized polluting probability
Importance of air flow regimeImportance of air flow regimeImportance of air flow regimeImportance of air flow regime
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Due to the quad suspensionStructures it is impossible toEstablish pure Laminar Flow in the test mass region
Importance of air flow regimeImportance of air flow regimeImportance of air flow regimeImportance of air flow regime
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Detailed Flow conditions To be simulatedExample: Flomerics.com
Importance of air flow regimeImportance of air flow regimeImportance of air flow regimeImportance of air flow regime
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Flow conditions to be simulated
Examples of clean room air flow simutationExamples of clean room air flow simutationExamples of clean room air flow simutationExamples of clean room air flow simutation
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The Laminar Flow curtains plussemi-laminar flow core seem to be the best solution for the BSC chambers andGuarantee a reasonable Protection against contaminants
Importance of air flow regimeImportance of air flow regimeImportance of air flow regimeImportance of air flow regime
