Laser Interferometer Gravitational Wave Observatorywillems/OpLev/Optical Lever... · Web view......

LASER INTERFEROMETER GRAVITATIONAL WAVE OBSERVATORY

LIGO Laboratory / LIGO Scientific Collaboration

LIGO-T000092-02-D ADVANCED LIGO 10/4/00

Auxiliary Optics Support SystemDesign Requirements Document, Vol. 6:

Optical Lever System

Michael Smith, Michael Zucker, Ken Mason, Phil Willems

Distribution of this document:LIGO Science Collaboration

This is an internal working noteof the LIGO Project.

California Institute of TechnologyLIGO Project – MS 18-341200 E. California Blvd.

Pasadena, CA 91125Phone (626) 395-2129Fax (626) 304-9834

E-mail: [email protected]

Massachusetts Institute of TechnologyLIGO Project – NW17-161

175 Albany StCambridge, MA 02139Phone (617) 253-4824Fax (617) 253-7014

E-mail: [email protected]

LIGO Hanford ObservatoryP.O. Box 1970

Mail Stop S9-02Richland, WA 99352Phone 509-372-8106Fax 509-372-8137

LIGO Livingston ObservatoryP.O. Box 940

Livingston, LA 70754Phone 225-686-3100Fax 225-686-7189

http://www.ligo.caltech.edu/

Advanced LIGO LIGO-T000092-02-D

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Table of Contents1 INTRODUCTION.....................................................................................................................................................6

1.1 PURPOSE...........................................................................................................................................................61.2 SCOPE................................................................................................................................................................6

1.2.1 Optical Lever System (OptLev)....................................................................Error! Bookmark not defined.1.3 DEFINITIONS.....................................................................................................................................................61.4 ACRONYMS.......................................................................................................................................................61.5 APPLICABLE DOCUMENTS................................................................................................................................7

1.5.1 LIGO Documents.........................................................................................................................................71.5.2 Non-LIGO Documents.................................................................................................................................8

2 GENERAL DESCRIPTION...................................................................................................................................9

2.1 SPECIFICATION TREE........................................................................................................................................92.2 PRODUCT PERSPECTIVE....................................................................................................................................9

2.2.1 Optical Lever System Perspective.............................................................................................................102.3 PRODUCT FUNCTIONS.....................................................................................................................................10

2.3.1 Optical Lever System Functions................................................................................................................102.4 GENERAL CONSTRAINTS.................................................................................................................................10

2.4.1 Optical Lever System Constraints.............................................................................................................112.5 ASSUMPTIONS AND DEPENDENCIES................................................................................................................11

2.5.1 Core Optics Parameters............................................................................................................................112.5.2 Interferometer Design Parameters............................................................................................................122.5.3 ISC Interface Characteristics....................................................................................................................12

2.5.3.1 ISC Sensor Beam Parameters............................................................................................................................122.5.4 Seismic Environment.................................................................................................................................13

3 REQUIREMENTS.................................................................................................................................................14

3.1 OPTICAL LEVER SYSTEM REQUIREMENTS......................................................................................................143.1.1 Optical Lever System Characteristics.......................................................................................................14

3.1.1.1 Optical Lever System Performance Characteristics..........................................................................................143.1.1.2 Optical Lever System Physical Characteristics.................................................................................................153.1.1.3 Optical Lever System Interface Definitions......................................................................................................153.1.1.4 Optical Lever System Reliability......................................................................................................................153.1.1.5 Optical Lever System Maintainability...............................................................................................................153.1.1.6 Optical Lever System Environmental Conditions.............................................................................................163.1.1.7 Optical Lever System Transportability.............................................................................................................16

3.1.2 Optical Lever System Design and Construction........................................................................................173.1.2.1 Materials and Processes.....................................................................................................................................173.1.2.2 Optical Lever System Workmanship.................................................................................................................183.1.2.3 Optical Lever System Interchangeability..........................................................................................................183.1.2.4 Optical Lever System Safety.............................................................................................................................183.1.2.5 Optical Lever System Human Engineering.......................................................................................................18

3.1.3 Optical Lever System Assembly and Maintenance....................................................................................183.1.4 Optical Lever System Documentation.......................................................................................................19

3.1.4.1 Optical Lever System Specifications.................................................................................................................193.1.4.2 Optical Lever System Design Documents.........................................................................................................193.1.4.3 Optical Lever System Engineering Drawings and Associated Lists.................................................................193.1.4.4 Optical Lever System Technical Manuals and Procedures...............................................................................193.1.4.5 Optical Lever System Documentation Numbering...........................................................................................193.1.4.6 Optical Lever System Test Plans and Procedures.............................................................................................19

3.1.5 Optical Lever System Logistics.................................................................................................................203.1.6 Optical Lever System Precedence.............................................................................................................203.1.7 Optical Lever System Qualification...........................................................................................................20

4 QUALITY ASSURANCE PROVISIONS...........................................................................................................21

4.1 GENERAL........................................................................................................................................................21

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4.1.1 Responsibility for Tests..............................................................................................................................214.1.2 Special Tests..............................................................................................................................................21

4.1.2.1 Engineering Tests..............................................................................................................................................214.1.2.2 Reliability Testing.............................................................................................................................................21

4.1.3 Configuration Management.......................................................................................................................214.2 QUALITY CONFORMANCE INSPECTIONS..........................................................................................................21

4.2.1 Inspections.................................................................................................................................................214.2.2 Analysis......................................................................................................................................................224.2.3 Demonstration...........................................................................................................................................224.2.4 Similarity...................................................................................................................................................224.2.5 Test............................................................................................................................................................22

5 PREPARATION FOR DELIVERY.....................................................................................................................23

5.1 PREPARATION.................................................................................................................................................235.2 PACKAGING.....................................................................................................................................................235.3 MARKING........................................................................................................................................................23

6 Notes........................................................................................................................................................................24

AppendicesAppendix A Quality Conformance Inspections__________________________________________25

Table of TablesTable 1 Environmental Performance Characteristics.......................................................................16Table 2 Quality Conformance Inspections........................................................................................25

Table of FiguresFigure 1: Overall LIGO detector requirement specification tree......................................................10

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Abstract

This technical note is being generated to provide a general outline to be followed for developing a Design Requirements Document (DRD) for the LIGO Detector Group. The following pages provide the outline, including section/paragraph numbering and headings, along with a brief explanation (and some examples) of what is to go into each paragraph.

The basis for the following outline is a combination of the IEEE guide for software requirement documentation and the MIL-STD-490A guide to requirement specification. Sections 1 and 2 particularly follow the IEEE standard. The remaining sections are more in line with the MIL-STD format, with some extras or variations that I’ve found useful in the past.

This document is a MicroSoft Word template. All instructions (guidelines and examples) in this document are in normal text, and should be deleted when an individual DRD is written. This document also shows “boilerplate” text, which should appear in every LIGO detector DRD. This boilerplate appears in this document as italic text and should not be removed from individual DRDs.

This section (Abstract) was purposely titled without using the LIGO tech document template ‘Header’ paragraph format, such that the Table of Contents of this document directly reflects the outline for a DRD.

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1 Introduction

1.1 Purpose

The purpose of this document is to describe the design requirements for the Auxiliary Optics Support (AOS). Primary requirements are derived (“flowed-down”) from the LIGO principal science requirements. Secondary requirements, which govern Detector performance through interactions between AOS and other Detector subsystems, have been allocated by Detector Systems Engineering (see Figure 1.)

1.2 Optical Lever System Scope

Identify the item to be produced by name, such as Alignment Sensing and Control.

Explain what the item will and, if necessary, will not do. An example of the latter, from the CDS document is: CDS specifically does not provide: 1) Personnel safety system 2) Facilities Control System 3) etc. The point is to emphasize to reviewers what the system will not do where there may be some doubt or uncertainty.

Describe the objectives, goals of the item development.

The Optical Lever subsystem will provide an external means of monitoring the LIGO-2 core optic orientation. The optical levers will be used for long term monitoring and maintenance. They are not intended as feedback devices to the ASC Alignment Sensing and Control subsystem.

The optical lever system will be similar to the LIGO-1 system with revisions to accommodate changes to core optic positioning , materials, and other AOS system changes.

1.3 Definitions

Define all terms used in the document as necessary to interpret its contents. For example, a CDS specification may make use of terminology, such as “real-time software”, which is subject to interpretation. This section should specifically define what “real-time software” means in the context of this document.

NOTE: This should include all standard names used in interface discussions/drawings.

1.4 Acronyms

List all acronyms and abbreviations used in the document.

LIGO - Laser Interferometer Gravity Wave Observatory

COS - Core Optics Support

IOO - Input Optics

DRD - Design Requirements Document

SRD - Science Requirements Document

RM - Recycling Mirror

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BS - Beam Splitter

ITMx, ITMy - Input Test Mass in the interferometer ‘X’ or ‘Y’ arm

ETMx, ETMy - End Test Mass in the interferometer ‘X’ or ‘Y’ arm

AR - Antireflection Coating

HR - Reflective mirror coating

GBAR - Ghost Beam from AR side of COC

GBHR - Ghost Beam from HR side of COC

PO - Pick-off Beam

vh - Vacuum housing

SEI - Seismic Isolation subsystem

SUS - Suspension subsystem

ppm - parts per million

ISC- Interferometer Sensing and Control

LSC - Length Sensing and Control

COC - Core Optics Components

ASC - Alignment Sensing and Control

IFO - LIGO interferometer

HAM - Horizontal Access Module

BSC - Beam Splitter Chamber

BRDF - Bi-directional Reflectance Distribution Function

TBD - To Be Determined

APS - anti-symmetric port signal

SPS - symmetric port signal

rms - root-mean-square

p-v, peak to valley

1.5 Applicable Documents

List all documents referenced. Include only those expressly mentioned within this document.

1.5.1 LIGO Documents

Core Optics Support Design Requirements Document lIGO-T970071-03-D

Core Optics Components DRD: LIGO-Exxx

ISC Reference Design

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Seismic Isolation DRD, LIGO-T960065-02-D

Locally Damped Test Mass Motion, LIGO-T970092-00-D

Advanced LIGO Detector Design Requirements Document: LIGO-Exxx

Core Optics Support Conceptual Design, LIGO-T970072-00-D

COS Beam Dump and Stray Light Baffle Revised Req. and Concepts LIGO-T980103-00-D

Up-conversion of Scattered Light Phase Noise from Large Amplitude Motions, LIGO-T980101-00D

Effect of PO Telescope Aberrations on Wavefront Sensor Performance, LIGO-T980007-00-D

LIGO Vacuum Compatibility, Cleaning Methods and Procedures, LIGO-E960022-00-D

ASC Optical Lever Design Requirement Document, LIGO-T950106-01-D

LIGO-E000007-00

LIGO Naming Convention (LIGO-E950111-A-E)

LIGO Project System Safety Management Plan LIGO-M950046-F

LIGO EMI Control Plan and Procedures (LIGO-E960036)

Derivation of CDS Rack Acoustic Noise Specifications, LIGO-T960083

Specification Guidance for Seismic Component Cleaning, Baking, and Shipping Preparation (LIGO-L970061-00-D)

COS Preliminary Design T980010-01-D

1.5.2 Non-LIGO Documents

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2 General descriptionThis section (Section 2) should describe the general factors that affect the product and its requirements. This section does not state specific requirements; it only makes those requirements easier to understand.

2.1 Specification Tree

This document is part of an overall LIGO detector requirement specification tree. This particular document is highlighted in the following figure.

2.2 Product Perspective

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Figure 1: Overall LIGO detector requirement specification tree

2.2.1 Optical Lever System Perspective

The Optical Lever System will be positioned on the face of the suspended optic prior to removal of the IAS Initial Alignment subsystem. It will then monitor the angular orientation to assure no movement occurs during the period from alignment to operation.

2.3 Product Functions

This section should provide a summary of the functions that the specified item will perform. This should just be general statements, not the detail that will go into the requirements section (Section 3).

2.3.1 Optical Lever System Functions

The Optical Lever System provides two primary functions. It provides a means of monitoring the optic orientation for long-term drift due to the suspensions or seismic isolation system. It also provides maintenance and setup functions such as diagonalization of the core optic, core optic replacement, and realignment caused by catastrophic events (i.e. earthquakes).

2.4 General Constraints

This section should give a general description of any other items that will limit the designer’s options, such as general policies, design standards, interfaces, etc. This subsection should not be used to impose specific requirements or specific design constraints on the solution. This subsection should provide the reasons why certain specific requirements or design constraints are later specified as part of Section 3. A CDS example for the CDS PSL document might be:

The overall CDS system is being developed using VME based systems as the standard interface. Therefore, all I/O modules being developed for the PSL will be constrained to this format.

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Another general example might be:

LIGO must operate continuously, therefore this subsystem must be designed with high reliability and low mean time to repair. (Note that this is a general statement, and the MTBF and MTTR will be exactly specified in Section 3).

2.4.1 Optical Lever System Constraints

In order for the optical levers to provide stable monitoring of the optic orientation it must not be influenced by thermal or load induced movements of the seismic isolation or vacuum chambers. This requires that the laser source and photo detector be kinematically mounted and secured to the concrete foundation.

2.5 Assumptions and Dependencies

This section should list factors that affect the requirements i.e. certain assumptions have been made in the writing of the requirements, and, if these change, then the requirements will have to be changed. For example, it is assumed that green light wavelengths will be used as the basis for optics requirements. If this is changed to infrared, then the requirements that follow will need to change.

2.5.1 Core Optics Parameters

See Core Optics Components DRD: LIGO-Exxx

Physical Quantity RM SM BS ITMx ITMy ETM

AR coating @ 1060 nm ~0.001 <0.0001 <0.0001 0.0006 0.0006 <0.0003

AR coating @ 940 nm >0.4 >0.4 >0.4 >0.4 NA

Mirror power loss fraction 0.00005 0.00005 0.00005

mirror reflectivity @ 1060 nm 0.97 0.5 0.995 0.995 0.99994

mirror reflectivity @ 940 nm >0.4 >0.4 >0.4 >0.4 >0.4

mirror reflectivity @ 670 nm >0.04 >0.04 >0.04 >0.04 >0.04

refractive index @ 1064 nm 1.44963 1.44963 1.7546 1.7546 1.7546

100ppm power contour radius, mm 116 116 116 116 116

1ppm power contour radius, mm 142 142 142 142 142

beam radius parameter w, mm 54 54 54 54 54

Mirror diameter, mm 265 265 350 314 314 314

Mirror thickness, mm 100 100 60 130 130 130

Note: the mirror sizes and AR coatings are up to date from Gari’s COC table, July 15 2003. All else is inherited. Note FM is missing.

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2.5.2 Interferometer Design Parameters

The stray light calculations were based on the following assumed parameters:

Laser input power 125 watts

SPS power 2.5 watts

APS power 1.0 Watt

IFO Gaussian beam radius, w 54 mm

Recycling cavity gain 16.8

Arm cavity gain 789

2.5.3 ISC Interface Characteristics

2.5.3.1 ISC Sensor Beam Parameters

The COS PO beam characteristics will be compatible with the ISC design. ISC Reference Design:-________? The beam characteristics at the exit of the HAM viewport are as follows:

Physical Quantity Characteristic

Output PO beam aperture: APS, BS, ITM

20 mm

Output PO beam aperture: ETM

20 mm

wavefront distortion < 0.7 wave p-v

beam waist position TBD

Gaussian beam radius parameter

w = 4.2 mm

beam height Centered on the viewport

beam orientation nominally horizontal

beam polarization horizontal (TBD)

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2.5.4 Seismic Environment

The scattered light noise calculations in this document are based on the assumption that the rms velocity of scattering surfaces is sufficiently low so that up-conversion of large amplitude low fre-quency motion does not produce in-band phase noise. This is true for the vacuum housing and is also true of the SEI platforms for stack Q’s less than 1000. See Seismic Isolation DRD, LIGO-T960065-02-D, and Locally Damped Test Mass Motion, LIGO-T970092-00-D.

The ground noise spectrum for the scattered light noise calculations is assumed to be the LIGO Composite Ground Noise Spectrum for frequencies between 10 and 1000 Hz, as described in figure 10, LIGO-T960065.

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3 RequirementsThis section contains the specific requirements of the product to be developed. This is the most important part of the document. It must be:

Unambiguous: every requirement listed has only one interpretation

Complete: Inclusion of all significant requirements

Verifiable: A requirement is verifiable if and only if there exists some finite cost-effective process whereby the final product can be checked/tested to meet the requirement. If no method can be devised to determine if the product meets a particular requirement, either (1) the requirement should be removed, or (2) a point in the development cycle should be identified at which the requirement can be put into a verifiable form.

Consistent: No two requirements should conflict with each other.

Modifiable: The structure and style should be such that any necessary changes can be made easily, completely, and consistently.

Traceable: Backward (references to source of requirements, such as a higher level specification, design, or standards) and Forward (unique numbering of requirements such that they can be identified/referenced in design and test documentation).

Usable during operations and maintenance: often items are modified during commissioning and maintenance periods. The requirements should specifically call out critical areas (such as failure of this component to meet this requirement can cause severe injury), and other such items, such that this fact s not lost to maintenance personnel.

3.1 Optical Lever System Requirements

Suspended Core optics and the final IO optic will be monitored during and after installation by an optical lever system. This system will provide an angular readout of the pitch and yaw angles of the optic with respect to the local facility foundation.

3.1.1 Optical Lever System Characteristics

3.1.1.1 Optical Lever System Performance Characteristics

The optical lever is intended as a reference for core optic alignment to maintain continuity between installation and operation. Its performance is limited by motions of the facility foundations; for example, pump down of a vacuum equipment component section is likely to induce floor tilts of order 100 micro radian, and changes due to cycling temperature gradients in the order of tens of micro radians. However these effects are in principle predictable and measurable. As a result the long-term stability of the optical lever performance will be +/- 50 micro radian peaks over extended time periods.

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3.1.1.2 Optical Lever System Physical Characteristics

The optical levers must be isolated mechanically from the vacuum chambers and view ports in order to not be effected by pump down or thermal movements of the vacuum system. Flexible bellows will enclose the laser beam and provide isolation from for the optical lever systems.

3.1.1.3 Optical Lever System Interface Definitions

3.1.1.3.1 Interfaces to other LIGO detector subsystems

3.1.1.3.1.1 Mechanical Interfaces

Optical lever structures must be secured directly to the foundation. Examples of accepted structures include rigid stands and seismic piers. The laser source and photodiode assemblies are to be coupled to the vacuum viewports such that no thermal or vacuum induced movement is translated to the optical lever.

3.1.1.3.1.2 Electrical Interfaces

The laser source requires 5v electrical power and current sensing. The photodiode voltage output is fed to the DAQ system for monitoring.

3.1.1.3.1.3 Optical Interfaces

Clearance must be made for optical lever beams to pass through AOS baffles.

3.1.1.3.1.4 Stay Clear Zones

3.1.1.3.2 Interfaces external to LIGO detector subsystems

3.1.1.3.2.1 Mechanical Interfaces

3.1.1.3.2.2 Electrical Interfaces

3.1.1.3.2.3 Stay Clear Zones

3.1.1.4 Optical Lever System Reliability

Optical lever laser sources are to have a MTBF of 10,000 hours.

3.1.1.5 Optical Lever System Maintainability

The following components are susceptible to failure:

1. Diode laser source assembly.

2. Motorized optic mount.

3. Photodiode assembly.

Each of these items is to have plug connections and are easily replaceable. Re-alignment of the laser source and photodiode calibration can be accomplished in less than 1 day.

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3.1.1.6 Optical Lever System Environmental Conditions

3.1.1.6.1 Natural Environment

3.1.1.6.1.1 Temperature and Humidity

Example:

Table 1 Environmental Performance Characteristics

Operating Non-operating (storage) Transport

+15C to +45C, non- condensing

0C to +50C, non-condensing

0C to +50C, non- condensing

3.1.1.6.1.2 Atmospheric Pressure

3.1.1.6.1.3 Seismic Disturbance

The optical lever system requires a stable, rigid foundation for accurate monitoring of optic orientation. The optical lever source, receiver, and optic should be on a common block. The first bending mode of the foundation block should be greater than 100 Hz.

3.1.1.6.2 Induced Environment

3.1.1.6.2.1 Electromagnetic Radiation

Electrical equipment associated with the subsystem shall meet the EMI and EMC requirements of VDE 0871 Class A or equivalent. The subsystem shall also comply with the LIGO EMI Control Plan and Procedures (LIGO-E960036).

3.1.1.6.2.2 Acoustic

Equipment shall be designed to produce the lowest levels of acoustic noise as possible and practical. As a minimum, equipment shall not produce acoustic noise levels greater than specified in Derivation of CDS Rack Acoustic Noise Specifications, LIGO-T960083.

3.1.1.6.2.3 Mechanical Vibration

Mechanical vibration from the subsystem shall not increase the vibration amplitude of the facility floor within 1 m of any other vacuum chambers and equipment tables by more than 1 dB at any frequency between 0.1 Hz and 10 kHz. Limited narrowband exemptions may be permitted subject to LIGO review and approval.

3.1.1.7 Optical Lever System Transportability

All items shall be transportable by commercial carrier without degradation in performance. As necessary, provisions shall be made for measuring and controlling environmental conditions

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(temperature and accelerations) during transport and handling. Special shipping containers, shipping and handling mechanical restraints, and shock isolation shall be utilized to prevent damage. All containers shall be movable for forklift. All items over 100 lbs. which must be moved into place within LIGO buildings shall have appropriate lifting eyes and mechanical strength to be lifted by cranes.

3.1.2 Optical Lever System Design and Construction

The optical lever system is designed and constructed with long-term stability in mind. The interface between materials of different coefficients of expansion is to be kinematically mounted in such a way that expansion will occur in the direction of the beam.

3.1.2.1 Materials and Processes

The materials and processes used in the fabrication of the Initial Alignment subsystem shall be compatible with the LIGO approved materials list.

3.1.2.1.1 Finishes

Ambient Environment: Surface-to-surface contact between dissimilar metals shall be controlled in accordance with the best available practices for corrosion prevention and control.

External surfaces: External surfaces requiring protection shall be painted purple or otherwise protected in a manner to be approved.

• Metal components shall have quality finishes on all surfaces, suitable for vacuum finishes.

• All corners shall be rounded to TBD radius.

• All materials shall have non-shedding surfaces.

• Aluminum components used in the vacuum shall not have anodized surfaces.

• Optical table surface roughness shall be within 32 micro-inch.

3.1.2.1.2 Materials

A list of currently approved materials for use inside the LIGO vacuum envelope can be found in LIGO Vacuum Compatible Materials List (LIGO-E960022). All fabricated metal components exposed to vacuum shall be made from stainless steel, copper, or aluminum. Other metals are subject to LIGO approval. Pre-baked viton (or fluorel) may be used subject to LIGO approval. All materials used inside the vacuum chamber must comply with LIGO Vacuum Compatibility, Cleaning Methods and Procedures (LIGO-E960022-00-D).

The only lubricating films permitted within the vacuum are dry plating of vacuum compatible materials such as silver and gold.

3.1.2.1.3 Processes

3.1.2.1.3.1 Welding

Before welding, the surfaces should be cleaned (but baking is not necessary at this stage) according to the UHV cleaning procedure(s). All welding exposed to vacuum shall be done by the tungsten-arc-inert-gas (TIG) process. Welding techniques for components operated in vacuum shall deviate from the ASME Code in accordance with the best ultra high vacuum practice to eliminate any

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“virtual leaks” in welds; i. e. all vacuum welds shall be continuous wherever possible to eliminate trapped volumes. All weld procedures for components operated in vacuum shall include steps to avoid contamination of the heat affected zone with air, hydrogen or water, by use of an inert purge gas that floods all sides of heated portions.

The welds should not be subsequently ground (in order to avoid embedding particles from the grinding wheel).

3.1.2.1.3.2 Cleaning

All materials used inside the vacuum chambers must be cleaned in accordance with Specification Guidance for Seismic Component Cleaning, Baking, and Shipping Preparation (LIGO-L970061-00-D). To facilitate final cleaning procedures, parts should be cleaned after any processes that result in visible contamination from dust, sand or hydrocarbon films.

Materials shall be joined in such a way as to facilitate cleaning and vacuum preparation procedures; i. e. internal volumes shall be provided with adequate openings to allow for wetting, agitation and draining of cleaning fluids and for subsequent drying.

3.1.2.1.4 Component Naming

All components shall be identified using the LIGO Naming Convention (LIGO-E950111-A-E). This shall include identification (part or drawing number, revision number, serial number) physically stamped on all components, in all drawings and in all related documentation.

3.1.2.2 Optical Lever System Workmanship

All components shall be manufactured according to good commercial practice.

3.1.2.3 Optical Lever System Interchangeability

Common elements, with ordinary dimensional tolerances will be interchangeable.

3.1.2.4 Optical Lever System Safety

This item shall meet all applicable NSF and other Federal safety regulations, plus those applicable State, Local and LIGO safety requirements. A hazard/risk analysis shall be conducted in accordance with guidelines set forth in the LIGO Project System Safety Management Plan LIGO-M950046-F, section 3.3.2.

3.1.2.5 Optical Lever System Human Engineering

Not applicable.

3.1.3 Optical Lever System Assembly and Maintenance

Assembly installation/calibration documentation shall be developed in conjunction with the optical lever hardware design.

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3.1.4 Optical Lever System Documentation

The documentation shall consist of working drawings, assembly drawings, and alignment procedures.

3.1.4.1 Optical Lever System Specifications

Specifications for the purchase of specialized components and assemblies such as diode lasers optical mirrors, windows, and targets shall be developed.

3.1.4.2 Optical Lever System Design Documents

Revised drawings and calibration documents will be produced.

3.1.4.3 Optical Lever System Engineering Drawings and Associated Lists

A complete set of drawings suitable for fabrication will be provided along with Bill of Material (BOM) and drawing tree lists. The drawings will comply with LIGO standard formats and must be provided in electronic format. All documents shall use the LIGO drawing numbering system, be drawn using LIGO Drawing Preparation Standards, etc.

3.1.4.4 Optical Lever System Technical Manuals and Procedures

3.1.4.4.1 Procedures

Procedures shall be provided for, at minimum,

• Initial installation and setup of equipment

• Normal operation of equipment

• Normal and/or preventative maintenance

• Installation of new equipment

• Troubleshooting guide for any anticipated potential malfunctions

3.1.4.4.2 Manuals

All manufacturer’s operating and installation manuals will be supplied and LIGO calibration procedures.

3.1.4.5 Optical Lever System Documentation Numbering

All documents shall be numbered and identified in accordance with the LIGO documentation control numbering system LIGO document TBD

3.1.4.6 Optical Lever System Test Plans and Procedures

All test plans and procedures shall be developed in accordance with the LIGO Test Plan Guidelines, LIGO document TBD.

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3.1.5 Optical Lever System Logistics

The design shall include a list of all recommended spare parts and special test equipment required.

3.1.6 Optical Lever System Precedence

3.1.7 Optical Lever System Qualification

Calibration of optical levers per LIGO documents T990026-00.

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4 Quality Assurance ProvisionsThis section includes all of the examinations and tests to be performed in order to ascertain the product, material or process to be developed or offered for acceptance conforms to the requirements in section 3.

4.1 General

This should outline the general test and inspection philosophy, including all phases of development.

4.1.1 Responsibility for Tests

Who is responsible for testing.

4.1.2 Special Tests

4.1.2.1 Engineering Tests

List any special engineering tests that are required to be performed. Engineering tests are those which are used primarily for the purpose of acquiring data to support the design and development.

4.1.2.2 Reliability Testing

Reliability evaluation/development tests shall be conducted on items with limited reliability history that will have a significant impact upon the operational availability of the system.

4.1.3 Configuration Management

Configuration control of specifications and designs shall be in accordance with the LIGO Detector Implementation Plan.

4.2 Quality conformance inspections

Design and performance requirements identified in this specification and referenced specifications shall be verified by inspection, analysis, demonstration, similarity, test or a combination thereof per the Verification Matrix, Appendix 1 (See example in Appendix). Verification method selection shall be specified by individual specifications, and documented by appropriate test and evaluation plans and procedures. Verification of compliance to the requirements of this and subsequent specifications may be accomplished by the following methods or combination of methods:

4.2.1 Inspections

Inspection shall be used to determine conformity with requirements that are neither functional nor qualitative; for example, identification marks.

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4.2.2 Analysis

Analysis may be used for determination of qualitative and quantitative properties and performance of an item by study, calculation and modeling.

4.2.3 Demonstration

Demonstration may be used for determination of qualitative properties and performance of an item and is accomplished by observation. Verification of an item by this method would be accomplished by using the item for the designated design purpose and would require no special test for final proof of performance.

4.2.4 Similarity

Similarity analysis may be used in lieu of tests when a determination can be made that an item is similar or identical in design to another item that has been previously certified to equivalent or more stringent criteria. Qualification by similarity is subject to Detector management approval.

4.2.5 Test

Test may be used for the determination of quantitative properties and performance of an item by technical means, such as, the use of external resources, such as voltmeters, recorders, and any test equipment necessary for measuring performance. Test equipment used shall be calibrated to the manufacture’s specifications and shall have a calibration sticker showing the current calibration status.

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5 Preparation for DeliveryPackaging and marking of equipment for delivery shall be in accordance with the Packaging and Marking procedures specified herein.

5.1 Preparation

• Vacuum preparation procedures as outlined in LIGO Vacuum Compatibility, Cleaning Methods and Procedures (LIGO-E960022-00-D) shall be followed for all components intended for use in vacuum. After wrapping vacuum parts as specified in this document, an additional, protective outer wrapping and provisions for lifting shall be provided.

• Electronic components shall be wrapped according to standard procedures for such parts.

5.2 Packaging

Procedures for packaging shall ensure cleaning, drying, and preservation methods adequate to prevent deterioration, appropriate protective wrapping, adequate package cushioning, and proper containers. Proper protection shall be provided for shipping loads and environmental stress during transportation, hauling and storage. The shipping crates used for large items should use for guidance military specification MIL-C-104B, Crates, Wood; Lumber and Plywood Sheathed, Nailed and Bolted. Passive shock witness gauges should accompany the crates during all transits.

For all components which are intended for exposure in the vacuum system, the shipping preparation shall include double bagging with Ameristat 1.5TM plastic film (heat sealed seams as practical, with the exception of the inner bag, or tied off, or taped with care taken to insure that the tape does not touch the cleaned part). Purge the bag with dry nitrogen before sealing.

5.3 Marking

Appropriate identification of the product, both on packages and shipping containers; all markings necessary for delivery and for storage, if applicable; all markings required by regulations, statutes, and common carriers; and all markings necessary for safety and safe delivery shall be provided.

Identification of the material shall be maintained through all manufacturing processes. Each component shall be uniquely identified. The identification shall enable the complete history of each component to be maintained (in association with Documentation “travelers”). A record for each component shall indicate all weld repairs and fabrication abnormalities.

For components and parts that are exposed to the vacuum environment, marking the finished materials with marking fluids, die stamps and/or electro-etching is not permitted. A vibratory tool with a minimum tip radius of 0.005" is acceptable for marking on surfaces that are not hidden from view. Engraving and stamping are also permitted.

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6 NotesThis section should contain information of a general or explanatory nature, and no requirements shall appear here. This could be such items as modeling data/results, R&D prototype information, etc.

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Appendix A Quality Conformance Inspections

Appendixes are used to append large data tables or any other items which would normally show up within the body of the specification, but, due to their bulk or content, tend to degrade the usefulness of the specification. Whenever an Appendix is used, it shall be referenced in the body of the specification.

Appendix 1 shall always contain a table that lists the requirements and the method of testing requirements. An example table follows. Additional appendixes can contain other information, as appropriate to the subsystem being specified.

Table 2 Quality Conformance Inspections

Paragraph Title I A D S T

3.2.1 Performance Characteristics

X

3.2.1.1 Controls Performance

X

3.2.1.2 Timing Performance‘

X X

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