Laser Interferometer Gravitational Wave Observatory



LIGO Laboratory / LIGO Scientific Collaboration

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

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Auxiliary Optics Support System

Design Requirements Document, Vol. 5:

Initial Alignment System

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Michael Smith, Michael Zucker, Ken Mason, Phil Willems

Distribution of this document:

LIGO Science Collaboration

This is an internal working note

of the LIGO Project.

|California Institute of Technology |Massachusetts Institute of Technology |

|LIGO Project – MS 18-34 |LIGO Project – NW17-161 |

|1200 E. California Blvd. |175 Albany St |

|Pasadena, CA 91125 |Cambridge, MA 02139 |

|Phone (626) 395-2129 |Phone (617) 253-4824 |

|Fax (626) 304-9834 |Fax (617) 253-7014 |

|E-mail: info@ligo.caltech.edu |E-mail: info@ligo.mit.edu |

| | |

|LIGO Hanford Observatory |LIGO Livingston Observatory |

|P.O. Box 1970 |P.O. Box 940 |

|Mail Stop S9-02 |Livingston, LA 70754 |

|Richland, WA 99352 |Phone 225-686-3100 |

|Phone 509-372-8106 |Fax 225-686-7189 |

|Fax 509-372-8137 | |



Table of Contents

1 Introduction 7

1.1 Purpose 7

1.2 Scope 7

1.2.1 Initial Alignment System (IAS) 7

1.3 Definitions 7

1.4 Acronyms 7

1.5 Applicable Documents 9

1.5.1 LIGO Documents 9

1.5.2 Non-LIGO Documents 9

2 General description 10

2.1 Specification Tree 10

2.2 Product Perspective 10

2.2.1.1 Layout 11

2.2.2 Initial Alignment System Perspective 12

2.3 Product Functions 12

2.3.1 Initial Alignment System Functions 12

2.4 General Constraints 12

2.4.1 Initial Alignment System Constraints 13

2.5 Assumptions and Dependencies 13

2.5.1 Core Optics Parameters 13

2.5.2 Interferometer Design Parameters 14

2.5.3 ISC Interface Characteristics 14

2.5.3.1 ISC Sensor Beam Parameters 14

2.5.4 Seismic Environment 15

3 Requirements 16

3.1 Initial Alignment System Requirements 16

3.1.1 Introduction 16

3.1.2 Initial Alignment System Characteristics 16

3.1.2.1 Initial Alignment System Performance Characteristics 16

3.1.2.2 Initial Alignment System Physical Characteristics 17

3.1.2.3 Initial Alignment System Interface Definitions 18

3.1.2.4 Initial Alignment System Reliability 19

3.1.2.5 Initial Alignment System Maintainability 19

3.1.2.6 19

3.1.2.7 Initial Alignment System Environmental Conditions 19

3.1.2.8 Initial Alignment System Transportability 20

3.1.3 Initial Alignment System Design and Construction 21

3.1.3.1 Materials and Processes 21

3.1.3.2 Initial Alignment System Workmanship 22

3.1.3.3 Initial Alignment System Interchangeability 22

3.1.3.4 Initial Alignment System Safety 22

3.1.3.5 Initial Alignment System Human Engineering 22

3.1.4 Initial Alignment System Assembly and Maintenance 22

3.1.5 Initial Alignment System Documentation 23

3.1.5.1 Initial Alignment System Specifications 23

3.1.5.2 Initial Alignment System Design Documents 23

3.1.5.3 Initial Alignment System Engineering Drawings and Associated Lists 23

3.1.5.4 Initial Alignment System Technical Manuals and Procedures 23

3.1.5.5 Initial Alignment System Documentation Numbering 23

3.1.5.6 Initial Alignment System Test Plans and Procedures 24

3.1.6 Initial Alignment System Logistics 24

3.1.7 Initial Alignment System Precedence 24

3.1.8 Initial Alignment System Qualification 24

4 Quality Assurance Provisions 25

4.1 General 25

4.1.1 Responsibility for Tests 25

4.1.2 Special Tests 25

4.1.2.1 Engineering Tests 25

4.1.2.2 Reliability Testing 25

4.1.3 Configuration Management 25

4.2 Quality conformance inspections 25

4.2.1 Inspections 25

4.2.2 Analysis 26

4.2.3 Demonstration 26

4.2.4 Similarity 26

4.2.5 Test 26

5 Preparation for Delivery 27

5.1 Preparation 27

5.2 Packaging 27

5.3 Marking 27

6 Notes 28

6.1.1 This 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, 28

Appendices

Appendix A Quality Conformance Inspections 99

Table of Tables

Table 1 Environmental Performance Characteristics 19

Table 2 Quality Conformance Inspections 28

Table of Figures

Figure 1: Overall LIGO detector requirement specification tree 10

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.

Introduction

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.)

2 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 Initial Alignment subsystem will provide a means of positioning the LIGO-2 suspended core optics in global coordinates and provide angular alignment to within 10% of the core optics adjustment range. This will allow the operator to use the CDS control system to position the beam back upon itself and to switch to the ASC Alignment Sensing and Control system.

Initial Alignment will be similar to the LIGO-1 system with revisions to accommodate changes to suspensions, core optic materials, and the active seismic isolation system.

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.

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

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

5 Applicable Documents

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

1 LIGO Documents

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

Core Optics Components DRD: LIGO-Exxx

ISC Reference Design

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

2 Non-LIGO Documents

General description

This 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.

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 Product Perspective

Figure 1: Overall LIGO detector requirement specification tree

1 Layout

A schematic layout of the detector assembly is shown in the figure following, indicating the physical relationship of the Stray Light Control subsystem elements to the rest of the detector system.

2 Initial Alignment System Perspective

The Initial Alignment system interfaces with Suspension design, Core Optic design, and all other AOS subsystems. The core optic provides reflectivity at 670 nm for the laser autocollimator to sense the return beam. The Suspensions system provides a means of measuring its position and the ability to make rough and fine linear and angular adjustments.

Initial Alignment is performed on each core optic individually. An AOS autocollimator operating at 980 nm is then used to verify the optical path thru a group of core optics.

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).

1 Initial Alignment System Functions

The Initial Alignment system will provide the monuments, instrumentation, and procedures to position and align the final Input Optic and all Advanced LIGO core optics to within the positioning and angular alignment requirements.

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.

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).

1 Initial Alignment System Constraints

Initial Alignment is constrained by existing internal vacuum and external equipment, which requires setting up from an offset centerline and the use of various optical techniques, and auxiliary equipment to meet positioning and orientation requirements.

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.

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 |0.4 |>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.

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 |Watt |

|IFO Gaussian beam radius, w |54 mm |

|Recycling cavity gain |16.8 |

|Arm cavity gain |789 |

| | |

3 ISC Interface Characteristics

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) |

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 frequency 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.

Requirements

This 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.

1 Initial Alignment System Requirements

1 Introduction

Initial alignment must set the Nd Yag laser beam within the range of adjustment of the COS such that a transition to acquisition alignment can take place.

One performance requirement on the Initial Alignment System is that it position the optics during installation correctly to within 10% of the core optic positioning control range. This range is determined by the SEI and SUS designs and design requirements. The SEI platforms are required have transverse position control (vertical and transverse horizontal) of (1mm, and yaw control of (.25mrad. The SEI platform design may exceed these requirements, but they are considered fixed for the purposes of setting Initial Alignment System requirements. The requirements for control authority in SUS are much less specific. Instead of precise ranges of authority, the requirement is that SUS have sufficient force and bandwidth to acquire lock and control the interferometer. The actual ranges will come from the design and are TBD.

2 Initial Alignment System Characteristics

1 Initial Alignment System Performance Characteristics

Angular positioning +/- 0.1 mrad (ITM, ETM, BS, RM, FM)

Transverse positioning +/- 1 mm (ITM, ETM)

+/- 5 mm (BS, RM, FM)

Axial positioning +/- 3 mm (ITM, ETM, BS, RM, FM)

Note: the above positioning requirements are taken from the initial LIGO ASC Initial Alignment document.

2 Initial Alignment System Physical Characteristics

Theodolite / 3-D Coordinate Measuring System

Telescope Magnification 30x

Resolving power 3”

Minimum focus 2m(6.6 ft.)

Angle Measurement

Display resolution 0.5"/0.1mgon/0.002mil, 1”/0.2mgon/0.005mil

Accuracy 2"(0.6mgon) (standard deviation according to DIN 18723)

Distance Measurement Range

2m(6.6ft) to 100m(328ft) (RS90 reflective sheets target)

50m(164ft) to 1000m(3,280ft) (using CPS12 high-precision reflective prism)

Accuracy

±(0.8 + 1ppm x D)mm (using RS or RT series reflective targets)

±(2.0 + 2ppm x D)mm (using CPS12 high-precision reflective prism)

General

Weight

Main unit 6.1 kg(13.4 lb.), Carrying case 3.9kg(8.6 lb.)

Transit Square

Telescope:

Length: 14 inches (with micrometer 190)

Magnification: 20X at 2 inches from objective; 30X at infinity

Field of View: 1 degree

Image: Erect

Optics: Low reflective, protective coating

Effective Aperture: 1.34 inches

Resolution: 3.9 arc seconds

Reticle: Glass, filar/bi-filar pattern (others available)

Focusing Range: 2 inches to infinity

Bearings: Ball type with a run out of 0.000025 of an inch or less

Approximate Weight: Instrument, 34 pounds; instrument and case, 54

pounds; shipping, 56 pounds

Laser Autocollimator

Source Visible laser diode modulated at 10 kHz

Wavelength 670 nm

Peak power 900 µW (Class II)

Beam diameter 31 mm

Beam divergence 100 µrad

Beam direction 500 µrad

Equivalent focal length 280 mm

Measurement field ±2000 µrad

Ocular field ±15 mrad (±1.1°)

Resolution 0.1 µrad

Measurement distortion ±1 {±0.02 x measurement} µrad (i.e. 2%)

Reflector Min. 2% reflectivity

Noise 0.02 µrad/­Hz (at 100% reflectivity)

Weight 1.1 kg

3 Initial Alignment System Interface Definitions

1 Interfaces to other LIGO detector subsystems

1 Mechanical Interfaces

The PLX retro reflector and the optical flat are auxiliary alignment equipment, which must lie within the vacuum tube spool pieces.

2 Electrical Interfaces

There are no electrical interfaces.

3 Optical Interfaces

There are no optical interfaces.

4 Stay Clear Zones

During critical alignments a roped off area of 48” minimum is required to prevent disturbance of the alignment equipment.

2 Interfaces external to LIGO detector subsystems

There are no interfaces external to the LIGO detector subsystem.

4 Initial Alignment System Reliability

There are no published system reliability for alignment instrumentation. Alignment equipment is supplied to each site. In the event of failure the equipment from the alternate site will be available as backup.

5 Initial Alignment System Maintainability

The following calibrations should be performed following shipment, storage or extended use:

Theodolite / 3-D Coordinate Measuring System

• Adjust tilt sensing error per appendix 2 of Field Manual.

• Check optical plummet accuracy per page 155 of Field Manual.

• Check double centering error per page 149 of Field Manual.

Transit Square

• Check squareness per LIGO T970151-C appendix B.

• Check double centering error per Field Manual.

• Check horizontal axis with vertical wire per Field Manual.

Laser Autocollimator

• Check accuracy per auto calibration kit supplied.

6

7 Initial Alignment System Environmental Conditions

1 Natural Environment

1 Temperature and Humidity

Table 1 Environmental Performance Characteristics

|Operating |Non-operating (storage) |Transport |

|17°C to +24°C (62°F to 75°F) |-10°C to +40°C (14°F to 104°F) |-10°C to +40°C (14°F to 104°F) |

2 Atmospheric Pressure

3 Seismic Disturbance:

The Initial Alignment equipment requires a stable, rigid foundation for accurate angular alignment. The alignment instruments and optic should be on a common block. The first bending mode of the foundation block should be greater than 100 Hz.

2 Induced Environment

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).

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 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.

8 Initial Alignment 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 (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 Initial Alignment System Design and Construction

The design and construction of the Initial Alignment equipment used in vacuum must allow for adequate cleaning, either on site or at an appropriate outside vendor, and shall fit inside the vacuum baking ovens on site.

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.

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.

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 Processes

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 “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).

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.

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.

2 Initial Alignment System Workmanship

All components shall be manufactured according to good commercial practice.

3 Initial Alignment System Interchangeability

Common elements, with ordinary dimensional tolerances will be interchangeable.

4 Initial Alignment 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.

5 Initial Alignment System Human Engineering

Platforms that bridge over piping and conduit are to be designed to minimize eye and back strain.

4 Initial Alignment System Assembly and Maintenance

Assembly fixtures and installation/replacement procedures shall be developed in conjunction with the AOS hardware design. These shall include (but not be limited to) fixtures and procedures for:

• AOS component insertion and assembly into the vacuum chambers without load support from the chambers

• assembly of the in vacuum components in a clean room (class 100) environment

• Initial alignment of the AOS components

5 Initial Alignment System Documentation

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

1 Initial Alignment System Specifications

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

2 Initial Alignment System Design Documents

The following documents will be produced:

• LIGO Initial Alignment Procedures Document.

• LIGO Initial Alignment Final Design Review Document

• LIGO Initial Alignment Installation and Commissioning Plans.

3 Initial Alignment System Engineering Drawings and Associated Lists

A complete set of drawings suitable for fabrication must be provided along with Bill of Material (BOM) and drawing tree lists. The drawings must 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.

4 Initial Alignment System Technical Manuals and Procedures

1 Procedures

The following procedures shall be provided:

• 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

2 Manuals

Provided by manufacturer.

5 Initial Alignment System Documentation Numbering

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

6 Initial Alignment System Test Plans and Procedures

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

6 Initial Alignment System Logistics

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

7 Initial Alignment System Precedence

The relative importance of the Initial Alignment subsystem requirements is as follows:

1) Optic position and orientation requirements.

2) Reflectivity of core optics at 670 nm.

3) Minimizing disturbances to existing core optics, auxiliary optics, and operating equipment.

8 Initial Alignment System Qualification

During the setup of the PO Mirror and Telescope Subsystem a 980 nm laser autocollimator is introduced into the beam path. This beam is traced thru the corner station optics to verify the positions and orientations of the core optics.

Quality Assurance Provisions

This 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.

1 General

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

1 Responsibility for Tests

Who is responsible for testing.

2 Special Tests

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.

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.

3 Configuration Management

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

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:

1 Inspections

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

2 Analysis

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

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 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.

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.

Preparation for Delivery

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

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.

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.

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.

Notes

1 This 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,

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 | | | | |X |

| |Characteristics | | | | | |

|3.2.1.1 |Controls Performance | |X | | | |

|3.2.1.2 |Timing Performance‘ | |X | | |X |

| | | | | | | |

| | | | | | | |

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Figure 2: Schematic Layout, Stray Light Control subsystem

LEGEND

Elliptical Baffle

Cryopump Baffle

Arm Cavity Baffle

ETM Telescope

PO/APS Telescope

PO Mirror

Cavity Beam Dump

IO Baffle

Viewport

Modecleaner Baffle

SPS

modecleaner

SM

ETMy

BS

RM

ITMx

ITMy

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