LIGO R&D 1G050557-00

UHV Cleanliness Requirements:UHV Cleanliness Requirements:Cleaning/Baking and Contamination Cleaning/Baking and Contamination

ControlControl

Dennis Coyne

HAM-SAS Bidder’s Conference@ LIGO Laboratory, Caltech

25 October 2005

Livingston, LA

Hanford, WA

LIGO R&D 2G050557-00

Basic UHV Compatibility Requirements

Cleanliness Requirements:» Achieve a Non-Volatile Residue (NVR) level of A/50 or better (per MIL-STD-

1246C or IEST-STD-CC1246D) on piece parts before clean assembly» Achieve a Particulate Cleanliness Level of 50 or better (per MIL-STD -

1246C or IEST-STD-CC1246D) on piece parts before clean assembly» Perform clean assembly and all steps through UHV Packaging in a Class

100 Clean Room (per FED-STD-209)» Comply with Contamination Control Protocols defined in E048228

(M990034 is also a good guide)» Package the Clean Parts per E048227

No Virtual Leaks» Full Penetration Welds

No Cold Welding» Stainless fasteners into Aluminum» Silver coated Stainless Fasteners into Stainless» Oversized pilot and tap for tapped holes

LIGO R&D 3G050557-00

Ultra-High Vacuum (UHV) Cleanliness Requirements Related to Manufacturing Processes

RECEIVE/INSPECT

MATERIALS/PARTS

MACHINE PRE-CLEAN

WELD

WIND

INSPECT TUNE

DIS-ASSEMBLE

PRECISIONCLEAN

AIR BAKEFTIRTEST

“CLEAN”ASSEMBLY(GAS TUNE)

PARTIALDISASSEMBLY

PACKSHIP

MARAGINGHEAT TREAT

STRESSRELIEF

WELDMENTMACHINING

POTTING

INSPECT“DIRTY”

ASSEMBLY -FIT CHECK

UHV COMPATIBLEMACHINING

RESTRICTIONS

UHV COMPATIBLEWELDING

RESTRICTIONS& FULL

PENETRATIONWELD

CERTIFICATION

“GROSSCLEANING” PER

MIL-STD-1246OR E048225

HA

ND

LIN

G/

CO

NT

AM

INA

TIO

NC

ON

TR

OL

PR

OT

OC

OL

FO

RW

IND

ING

S

REASONABLYCLEAN

ENVIRONMENT &HANDLING

“PRECISION CLEANING”PER MIL-STD-1246

OR E048225OR E960026

AIR BAKE PERsection 5.5 ofE970063-01(SIMILAR TO

E990452)

FTIR TEST PER MIL-STD-1246 OR

IEST-STD-CC1246DTO NVR LEVEL A/50

& PARTICULATELEVEL 100

CONTAMINATION CONTROL PERE048228

(REFERENCE M990034)CLASS 100 (PER FED-STD-209)

UHV PACKAGINGPER E048227(REFERENCE

M990034, E960022)

LIGO LAB QUALIFIESCONTRACTOR

CLEANING/BAKING/CONTAMINATION

CONTROL WITH TESTPIECES AND RGA PER

E960022

Notes: (1) The process sequence depicted

here is suggestive, and not meant to be prescriptive.

(2) Loaded GAS Filter, Spring Blades to be Creep Relaxed in Air Bake

LIGO R&D 4G050557-00

Practical UHV Requirements Must pre-clean parts before welding and winding Must clean parts multiple times during fabrication Must thoroughly clean parts!

» “gross” clean with solvents and acids» Mechanical clean (scrub) parts especially tapped holes – multiple times,

with powered rotary tool – during “gross” and “precision” clean steps» “precision” clean with hot, water soluble detergents (steam or hot water

spray) – multiple times» Never let parts dry with detergent» Multiple rinses with Deionized water

Must bake parts (air or vacuum) after “precision” cleaning Must maintain parts in a class 100 clean room

» or keep wrapped in “UHV Foil” and keep in at least a class 10,000 clean area)

» limit exposure, keep wrapped /covered when possible Must Control Contamination with Good Clean Room Practice

» All tools must be cleaned, air baked, wrapped & kept in Class 100 areas» All personnel must wear full clean room garb, including hair net, face mask

and gloves

LIGO R&D 5G050557-00

UHV Requirement References Particulate Level 50 and NVR Level A/50 per MIL-STD-1246C or IEST-STD-

CC1246D Cleaning for UHV Service:

» Contractor is to certify the cleaning and baking process with representative parts to demonstrate 1246 Level 50-A/50

– NVR Level to be confirmed via FTIR (Fourier Transform Infrared analysis)– Particulate level to be confirmed by particle sizing and counting or equivalent

particle area coverage» LIGO Lab will independently assess the contractor’s cleaning/baking process with

representative parts by RGA (mass spectrometer outgassing analysis) per E960022» Guidance: E048227, Process Specification for Ad-LIGO Seismic Isolation System In-

Vacuum Mechanical Elements: Fabrication (includes cleaning) Contamination Control:

» Per E048228, Process Specification for Ad-LIGO Seismic Isolation System In-Vacuum Mechanical Elements: Contamination Control

» Additional Guidance:– M990034, LIGO Contamination Control Plan– FED-STD-209, Airborne Particulate Cleanliness Classes in Cleanrooms and

Clean Zones– ISO-14644, Cleanrooms and controlled environments

[ISO-14644 superceeds FED-STD-209] Packaging:

» Per E048227, Process Specification for Ad-LIGO Seismic Isolation System In-Vacuum Mechanical Elements: UHV Packaging

LIGO R&D 6G050557-00

Clean Room & Gowning Room

HEPA Filter

Gowning Room

Class 100Clean Room

Class 10,000Room

“Sticky” Mat

LIGO R&D 7G050557-00

HAM Chamber Clean Rooms

“Full” Clean Room Dress

Concrete Floor – Cleaned Routinely, not ideal, but serviceable

LIGO R&D 8G050557-00

UHV Foil

Annealed (baked) UHV Aluminum Foil for Wrapping Parts