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ENGINEERING

SPECIFICATION

DOCUMENT (ESD)

Doc. No.

SP-391-000-65 R1

LUSI SUB-SYSTEM

CXI

Engineering Specifications for the CXI 1 micron KB System

Prepared by:

Sébastien Boutet Signature Date CXI Instrument Scientist

Reviewed by:

Paul Montanez Signature Date CXI Lead Engineer

Reviewed by:

Signature Date

Approved:

Darren Marsh Signature Date Quality Assurance Manager

Approved:

Tom Fornek Signature Date LUSI Project Manager

Revision Date Description of Changes Approved

R0 17OCT08 Initial release R1 25NOV08 Included a temperature controlled enclosure specification, Included long-trace profilometry and stitching interferometry as the technique for figure measurement, Update roughness values in the coating specification tables.

Clarified the sagittal curvature and slope error requirements.

Clarified language issues throughout the document

Added summary of specifications at the end of the document

L C L S U L T R A F A S T S C I E N C E I N S T R U M E N T S

ESD SP-391-000-65 CXI 1 micron KB System

Table of Contents

1. Overview

2. Scope

3. Applicable Documents, Specifications and Codes

3.1. SLAC Specifications

3.2. Other Specifications

4. Definitions

5. General Requirements

5.1. Location

5.2. Environment

5.3. Lifetime

6. Optical Requirements, Mirror Requirements

6.1. Scope

6.2. Mirror Definitions

6.3. Performance Requirements

6.4. Mirror Dimensions Requirements

6.5. Optical Surface Requirements

6.5.1. Figure Requirements

6.5.2. Roughness Requirements

6.6. Design and Construction

6.6.1. Substrate Material

6.6.2. Surface Finish

6.6.2.1. Optical Surface Area

6.6.2.2. Non-Optical Surface Areas

6.6.3. Workmanship

6.6.4. Test Coupons and Substrates

6.6.4.1. Test Coupons for Coating and Surface Qualification

6.6.4.2. Silicon Blank Substrate

6.6.5. Handling and Cleaning

6.6.5.1. Handling

6.6.5.2. Cleaning

6.6.6. Packaging and Shipping

6.6.7. Test Coupon Packaging and Shipping

6.6.8. Handling and Process Plan

6.7. Quality Assurance Provisions

6.7.1. General

6.7.1.1. Program Management

6.7.1.2. Progress Reporting

6.7.1.3. Reviews

6.7.1.4. Responsibility for Inspection and Tests

6.7.1.5. Inspection Test Procedure

6.7.1.6. In-Process Inspection Points

6.7.2. Quality Conformance Inspections

6.7.2.1. Visual Inspection

6.7.2.2. Characterization Metrology

6.7.3. Inspection Test Report

7. Coating Requirements

7.1. Coating Materials

7.2. Coating Figure

7.3. Coating Roughness

7.4. Workmanship

7.5. Process Development

7.6. Handling and Cleaning

7.6.1. Handling

7.6.2. Cleaning

7.7. Packaging and Shipping

7.8. Test Coupon Packaging and Shipping

7.9. Handling and Coating Process Plan

7.10. Quality Assurance Provisions

7.10.1. General

7.10.1.1. Program Management

7.10.1.2. Progress Reporting

7.10.1.3. Reviews

7.10.1.4. Responsibility for Inspection and Tests

7.10.1.5. Coating Inspection Test Procedure

7.10.1.6. In-Process Inspection Points

7.10.2. Quality Conformance Inspections

7.10.2.1. Characterization Metrology

7.10.3. Coating Inspection Test Report

7.11. Test Coupons

8. Metrology Requirements

8.1. Frequency of Measurements

8.2. Figure Measurements

8.3. Roughness Measurements

8.4. Power Spectral Density

8.5. Workmanship

8.6. Handling

8.7. Packaging and Shipping

8.8. Handling and Metrology Process Plan

8.9. Quality Assurance Provisions

8.9.1. General

8.9.1.1. Program Management

8.9.1.2. Progress Reporting

8.9.1.3. Reviews

8.9.2. Metrology Procedure

8.9.3. Characterization Metrology

8.9.4. Metrology Report

9. Mechanical Requirements

9.1. Mirror Support System Requirements

9.1.1. Scope

9.1.2. Design and Analysis

9.1.3. Performance Requirements

9.1.3.1. Precision motion

9.1.4. Positioning

9.1.5. Dimensions

9.1.6. Orientation

9.1.7. Mirror Mounting

9.1.8. Motion Limits

9.1.9. Cyclic Requirements

9.1.10. Mechanical Interfaces

9.1.11. Vacuum

9.1.12. Materials

9.1.13. Thermal Issues

9.1.13.1. Radiation Damage Issues

9.1.14. Alignment/Fiducialization

9.1.15. Stability

9.1.16. Kinematics/Supports

9.1.17. Workmanship

9.1.18. Handling and Cleaning

9.1.19. Packaging and Shipping

9.1.20. Mirror Support Handling and Process Plan

9.1.21. Electrical Requirements

9.1.22. Quality Assurance Provisions

9.1.22.1. General

9.1.23. Quality Assurance Requirements

9.1.23.1. Configuration Control

9.1.23.2. Program Management

9.1.23.3. Progress Reporting

9.1.23.4. Reviews

9.1.23.4.1. Technical Interface Meeting

9.1.23.4.2. Design Reviews (CDR, PDR, FDR) and Manufacturing Readiness Review

(MRR): 44

9.1.23.4.3. Pre-Ship Review (PSR)

9.1.24. Manufacturing and Assembly

9.1.24.1. Manufacturing

9.1.24.2. Verification and Test Plans

9.1.24.3. Inspection Requirements

9.1.24.4. Non-Conformance Control

9.1.24.5. End Item Data Package

9.1.25. Installation

9.1.26. Documentation

9.1.27. Part Marking

9.2. Vacuum Enclosure Requirements

9.2.1. Performance Requirements

9.2.2. Dimensions

9.2.3. Kinematics/Supports

9.2.4. Mechanical Interfaces

9.2.5. Ports

9.2.6. Vacuum Requirements

9.2.7. Seals

9.2.8. Materials

9.2.9. Mirror Support Mount

9.2.10. Thermal Issues

9.2.11. Alignment/Fiducialization

9.2.12. Stability

9.2.13. Workmanship

9.2.14. Handling and Cleaning

9.2.15. Packaging and Shipping

9.2.16. Electrical Requirements

9.2.17. Quality Assurance Provisions

9.2.18. Quality Assurance Requirements

9.2.19. Manufacturing and Assembly

9.2.20. Installation

9.2.21. Maintenance and Accessibility

9.2.22. Documentation

9.2.23. Part Marking

9.3. Stand Requirements

9.3.1. Performance Requirements

9.3.2. Mechanical Interfaces

9.3.3. Materials

9.3.4. Thermal Issues and Stability

9.3.5. Structural Issues

9.3.6. Motion

9.3.7. Color

9.3.8. Documentation

9.3.9. Part Marking

9.3.10. Quality Assurance Provisions

9.3.11. Quality Assurance Requirements

9.3.12. Manufacturing and Assembly

9.3.13. Installation

10. Major Interfaces

10.1. Stand and Vacuum Enclosure

10.2. Vacuum Enclosure and Mirror Support

10.3. Mirror Support and Mirrors

10.4. Differential Pumping

10.5. Both LUSI KB systems must be identical

11. Installation

12. Nonconformance and Corrective Action

13. Proprietary Information

14. Controls

15. Environmental Safety and Health Requirements

15.1. Seismic

15.2. Radiation Physics

15.3. Pressure Vessel/Vacuum Vessel

16. Demonstration of Capabilities by Vendors

17. Acronyms

18. Summary of the Specifications

18.1. Mirror Substrates

18.1.1. Substrate Specifications

18.1.2. Other Requirements

18.2. Mirror Mechanics

18.2.1. Mirror Support System

18.2.2. Other Specifications

18.2.3. Vacuum Enclosure

18.2.3.1. Vacuum Ports

18.2.4. Support Stand

1. Overview The Coherent X-ray Imaging (CXI) instrument to be built at the Linac Coherent Light Source (LCLS) by the LCLS Ultrafast Science Instruments (LUSI) project on the SLAC National Accelerator Laboratory site requires a mirror system to produce a 1x1 micron2 FWHM focal spot at the sample. The mirror system shall be made of 2 mirrors each with an elliptical figure and arranged in a Kirkpatrick-Baez (KB) configuration rotated by 45 degrees. The system is known as the CXI 1 Micron KB System or KB1.

The LCLS will produce a laser-like beam of X-rays in the 800 to 8300 eV range for the fundamental energy. Also, the 3rd harmonic will be present at up to 25 keV. The CXI instrument will use the hard X-ray branch which uses 2 offset mirrors that reflect energies between 2 keV and 25 keV. The KB mirrors will be located 420 m away from the source, which ranges in size from 60 µm to 78 µm FWHM, depending on the energy. The X-ray beam at the mirror location will range from 500 µm to 1500 µm depending on the energy.

The KB mirror combination shall reflect more than 75% of the X-rays over the 2-18 keV range. This will be achieved by coating the mirrors with two strips. The first strip will be a Silicon Carbide (SiC) monolayer and the second strip will be a bilayer consisting of a heavy material (either Rhodium (Rh) or Ruthenium (Ru)) deposited underneath a thin layer of Silicon Carbide (SiC).

These mirrors will be located in an Ultra-High Vacuum (UHV) environment (10-9 Torr).

They require a very precise positioning system with the mirrors located inside a vacuum enclosure which will be mounted on a stable stand.

2. Scope This document contains the specifications for the fabrication and delivery of a KB mirror system capable of producing a focal spot of roughly 1 µm x 1 µm (FWHM) for the CXI instrument built by LUSI at LCLS. Here, we say roughly 1 µm x 1 µm (FWHM) because the source size and location varies with the photon energy and therefore the focal spot will vary with energy and it will not be possible to obtain a 1 micron focus at all energies. The focus shall also not be smaller than 1 µm x 1 µm (FWHM) at any energy within the range of interest but may be larger than 1 µm x 1 µm (FWHM) at the lower energies. The specifications described in this document were chosen to satisfy this requirement. Multiple activities and components are required to build the complete mirror system. They are as followed.

Mirror Substrates (Described in Section 6)

Mirror Coating (Described in Section 7)

Mirror Metrology (Described in Section 8)

Mirror Mechanical Support System (Described in Section 9.1)

Vacuum Enclosure (Described in Section 9.2)

Support Stand (Described in Section 9.3)

All the requirements are summarized in Section 18 at the end of this document. The details for all these requirements are found in the Sections 3 to 17.

3. Applicable Documents, Specifications and Codes

3.1. SLAC Specifications

• SLAC document No. SP-391-000-25, “Physics Requirements for the CXI 1 micron

KB System”

• SLAC document No. SP-391-000-19, “Physics Requirements the CXI Instrument”

• SLAC document No. SP-391-001-41, “Physics Requirements the CXI 1 micron Sample Chamber”

• SLAC document No. SP-391-001-42, “Physics Requirements the CXI 1 micron Precision Instrument Stand”

• SLAC drawing No. DS-391-000-36, “Mechanical Design Standards Supplement”

• SLAC drawing No. SC-700-866-47, “Specification Kly & Vac Machining Fluids”

• Fed-STD-595B, “Colors Used in Government Procurement”

3.2. Other Specifications

• MIL-PRF-13830B: “Optical Components for Fire Control Instruments; General

Specification Governing the Manufacture, Assembly, and Inspection of.”

4. Definitions Mirror substrate vendor

The entity entering a contract with SLAC to provide mirrors meeting all requirements listed in Section 6.

Mirror coating vendor The entity entering a contract with SLAC to provide coating for mirrors meeting all requirements listed in Section 7.

Mirror metrology vendor The entity entering a contract with SLAC to provide metrology measurements on mirrors as described in Section 8.

Mirror support vendor The entity entering a contract with SLAC to provide a mirror mechanical support system meeting all requirements described in Section 9.1.

Vacuum enclosure vendor The entity entering a contract with SLAC to provide a vacuum enclosure meeting all requirements described in Section 9.2. This entity shall be the same entity as the mirror support vendor.

Stand vendor The entity entering a contract with SLAC to provide a stand meeting all requirements described in Section 9.3. This entity shall be the same entity as the mirror support vendor and the vacuum enclosure vendor.

5. General Requirements

5.1. Location

The vacuum enclosure of the KB mirror system will be located in experimental hutch 5 in the Far Experimental Hall of LCLS, known as FEH Hutch 5.

The midpoint between the 2 mirrors along the x-ray beam shall be located 384 m downstream of the exit of the LCLS undulator, which produces the X-ray beam. This same midpoint shall be located 8 m upstream of the focal point. The spacing between the 2 mirrors shall be kept to a minimum to minimize the overall length of the system.

5.2. Environment

The temperature and relative humidity in the FEH Hutch 5 will be maintained at (22.2°C +/-0.3°C), and 45% +/-10%, respectively.

The LUSI project will provide a temperature-controlled enclosure to encase the KB mirror system. This enclosure shall have a thermal stability of ±0.01 degree Celcius. The mirror system shall be designed to meet the thermal stability requirements listed in this document when enclosed in this environment with temperature controlled to ±0.01 degree Celcius.

5.3. Lifetime

The expected service life of the device is 10 years.

6. Optical Requirements, Mirror Requirements

6.1. Scope

This section describes the requirements for 2 mirrors to be delivered to SLAC. The mirrors shall be polished with an elliptical figure as described below.

6.2. Mirror Definitions

A pictorial definition of relevant terminology is given in Figure 1. The dimensions of the clear aperture are listed in Table 1 and Table 2. The clear aperture represents the optical surface where the surface quality requirements must be met. The requirements to the surface listed in Table 1 and Table 2 do not apply outside the clear aperture.

Figure 1: Pictorial definition of terminology

6.3. Performance Requirements

The mirrors will be used in a Kirkpatrick-Baez configuration rotated by 45 degrees (as shown in Figure 8) to produce a 1 micron FWHM focal spot. The mirrors will accept the full beam width (4 standard deviations or more) at all energies above 5 keV and will be > 86% reflective (each mirror for a total reflectivity > 75%) over the 2-18 keV range with the proper coating applied. The mirror parameters listed in Table 1 and Table 2 as well as the coating parameters listed in Table 3 and Table 4 were chosen to meet these requirements.

The mirror vendor shall be only responsible for meeting the requirements listed in these two tables and shall not be responsible for demonstrating or meeting the reflectivity requirements, which shall be met with proper coating given that the requirements of Table 3 and Table 4 are met.

6.4. Mirror Dimensions Requirements

The mirror substrate vendor shall produce mirrors with dimensions larger than the clear aperture defined in Table 1 and Table 2. The exact dimensions of the full mirror substrates, provided they are within the range listed in Table 1 and Table 2, are to be determined by the mirror substrate vendor, with the agreement of SLAC and the mirror support vendor.

The mirror substrate vendor shall provide the exact dimensions, on engineering drawings, of the mirror substrate to SLAC in response to the Request for Proposal from SLAC.

These dimensions will be used as design parameters for the mechanical system of the mirrors (Section 9.1) and must be fixed from the beginning, with no possibility for change unless agreed upon by SLAC. Provisions for any mounting features such as grooves and bevels shall be agreed upon by SLAC, the mirror substrate vendor and the mirror support vendor at the time of the contract award. The leading edge of the mirror shall have a chamfered edge to minimize radiation damage issues should the beam strike the leading edge.

6.5. Optical Surface Requirements

6.5.1. Figure Requirements

The mirrors shall have an elliptical profile to provide longitudinal focusing. The elliptical profile shall be obtained by machining of the optical surface. The mirrors shall have a limited curvature in the sagittal direction with a minimum radius of 400 m. All tangential roughness and slope errors are determined after subtraction of the best-fit elliptical reference surface from the clear aperture zone, in the case of pre-figured mirrors. In the sagittal direction, the slope error shall be determined after subtraction of the best-fit sagittal radius of curvature. Best-fit elliptical tangential radius or sagittal radius, must meet the respective surface radii specifications outlined in Table 1 and Table 2.

The figure error requirements are listed in Table 1 and Table 2.

Long-trace profilometry, full-aperture, visible-light interferometry, stitching interferometry, or another metrology technique approved by SLAC shall be used to determine the surface figure at the mirror substrate vendor’s facility, after processing of the mirrors surface has been completed. Verification of the mirror figure will be performed by a third party after delivery of the mirrors as described in Section 8.

The mirrors will not be arranged in the standard KB configuration. They will be rotated by 45 degrees which will cause the overall deflection of the beam to be horizontal only (the +X direction). The distortion of the figure of the mirror due to gravity in this orientation shall be taken into account and the mirrors shall meet all the specifications of Table 1 and

Table 2 when rotated to the 45 degree orientation. The first mirror shall deflect the beam 45 degrees down while the second mirror shall deflect the beam 45 degrees up, as shown on Figure 8.

It is the mirror substrate vendor’s responsibility to demonstrate that the effects of interferometer measurement error and gravity distortion are either negligible or are removed from the data

Parameter Value Units Comment 1 Mirror Shape Tangential ellipse Pre-figured mirrors

2 Clear aperture length 350 mm Length over which the coating will be applied and the surface specifications must be met 3 Clear aperture width 30 ≥ width

≥ 12 mm Width over which the 2 coating strips will be applied and the surface specifications must be met

4 Mirror Length 375 ≥ length ≥ mm Extra length is to allow mounting during the coating process and mirror use

5 Mirror Width 60 ≥ width ≥ 45 mm

6 Mirror Thickness >50 mm 7 Substrate material Si <100> Single crystal 8 Figure height error <1.00 nm rms Over dimensions from 1mm to the clear aperture size from best-fit ellipse 9 Mid-spatial roughness <0.25 nm rms Over the 10-3 to 0.5 µm-1 frequency range 10 High-spatial roughness <0.25 nm rms Over the 0.5 to 50 µm-1 frequency range 11 Tangential Slope error <0.25 µrad rms Over dimensions from 1mm to the clear aperture size from best-fit ellipse

12 Sagittal Slope error <2 µrad rms

Over dimensions from 1mm to the clear aperture width from best-fit sagittal radius

13 Mean Tangential Radius of curvature tolerance

0.1 %

14 Sagittal radius of curvature

>400 m

15 Distance from source 420 m 16 Focal length 8.2 m 17 Maximum incidence angle

3.4 mrad Angle of incidence at downstream end of the mirror 18 Vacuum pressure <10-9 Torr 19 Temperature 22 oC

Calculated parameters from the specifications A Maximum height of surface

3.24 µm Surface profile is shown on Figure 2 below.

For pre-figured mirrors only.

B Tangential Radius of curvature 4632-4932 m Elliptical profile (see Figure 3 below). For pre-figure mirrors only C Average incidence angle

3.364 mrad Angle of incidence at the mid-point of the mirror D Ellipse parameter (a) 214.1 m E Ellipse parameter (b) 197.4 mm

Table 1: Parameters for first mirror of KB1 system.

Figure 2: Surface profile of the first mirror.

Figure 3: Radius of curvature of the first mirror surface as a function of position along the mirror.

1 Mirror Shape Tangential ellipse Pre-figured mirrors

2 Clear aperture length 350 mm Length over which the coating will be applied and the surface specifications must be met

3 Clear aperture width 30 ≥ width ≥ 12 mm Width over which the 2 coating strips will be applied and the surface specifications must be met

4 Mirror Length 375 ≥ length ≥ 360 mm Extra length is to allow mounting during the coating process and mirror use

5 Mirror Width 60 ≥ width ≥ 45 mm

6 Mirror Thickness >50 mm 7 Substrate material Si <100> Single crystal 8 Figure height error <1.00 nm rms Over dimensions from 1mm to the clear aperture size from best-fit ellipse 9 Mid-spatial roughness <0.25 nm rms Over the 10-3 to 0.5 µm-1 frequency range 10 High-spatial roughness <0.25 nm rms Over the 0.5 to 50 µm-1 frequency range 11 Tangential Slope error <0.25 µrad rms Over dimensions from 1mm to the clear aperture size from best-fit ellipse

12 Sagittal Slope error <2 µrad rms

Over dimensions from 1mm to the clear aperture width from best fit sagittal radius

14 Mean Tangential Radius of curvature tolerance

0.1 %

15 Sagittal radius of curvature

>400 m

16 Distance from source 420 m 17 Focal length 7.8 m 18 Maximum incidence angle

3.4 mrad Angle of incidence at downstream end of the mirror 19 Vacuum pressure <10-9 Torr 20 Temperature 22 oC

Calculated parameters from the specifications A Maximum height of surface

3.40 µm Surface profile is shown on Figure 2 below.

For pre-figured mirrors only.

B Tangential Radius of curvature 4405-4706 m Elliptical profile (see Figure 3 below). For pre-figure mirrors only C Average incidence angle

3.363 mrad Angle of incidence at the mid-point of the mirror D Ellipse parameter (a) 213.9 m E Ellipse parameter (b) 192.4 mm

Table 2: Parameters for second mirror of KB1 system.

Figure 4: Surface profile of the second mirror.

Figure 5: Radius of curvature of the second mirror surface as a function of position along the mirror.

6.5.2. Roughness Requirements

The roughness requirements are listed in Table 1 and Table 2.

Roughness shall be measured on each mirror after cleaning. A visible-light interferometer or profilometer shall be used for mid-spatial frequency measurements at the mirror substrate vendor’s facility. If available, an AFM instrument shall be used for high-spatial frequency measurements at the mirror substrate vendor’s facility. If an AFM instrument is unavailable, alternative arrangements must be made by the mirror substrate vendor in agreement with SLAC.

Verification of the mid-spatial frequency roughness and the high-spatial frequency roughness will be performed by a third party with white-light optical profiling microscope and AFM capabilities as described in Section 8 after delivery of the mirrors.

6.6. Design and Construction

6.6.1. Substrate Material

The mirror substrate material shall be single-crystal silicon, with a <100> direction oriented along the "Length" of the mirror. It shall additionally be free from defects such as dislocations, cracks, etc. Any other substrate material options proposed by the vendor shall be approved by SLAC.

6.6.2. Surface Finish

6.6.2.1. Optical Surface Area

The mirror optical surface shall be finished using a SLAC approved technique to remove residual sub-surface damage and leave the optical surface in a stress-free condition. The mirror vendor shall describe the polishing technique to be used in the response to the Request for Proposals.

The mirror optical surface shall have no striae under visible examination.

The mirror optical surface shall meet a scratch/dig requirement of 10/5 per MILPRF- 13830B

6.6.2.2. Non-Optical Surface Areas

The mirror non-optical surface areas shall be finished using a controlled grinding process followed by wet-chemical etching to remove residual sub-surface damage and leave the non-optical surface areas in a stress-free condition. This process shall be staged such that all surfaces of the mirror shall be wet-chemical-etched before proceeding with the final polishing of the optical surface..

6.6.3. Workmanship

Workmanship shall be consistent with the quality necessary for stable operation of sensitive optical devices under long-term exposure to an x-ray, ultrahigh vacuum (UHV) environment similar to that found in synchrotron radiation user facilities.

6.6.4. Test Coupons and Substrates

6.6.4.1. Test Coupons for Coating and Surface Qualification

The mirror substrate vendor shall provide five single-crystal silicon test polishing coupons, for qualification of the SLAC reflective coating deposition process described in Section 7.

In order to make use of standard tooling, these test coupons should preferably be 2 inch diameter flat disks with a thickness of 3/8 inch. The exact shape and dimensions (including thickness) of the coupons are at the discretion of the mirror substrate vendor, but subject to negotiation and approval by SLAC. Each test coupon shall be polished/figured using the same processes to be applied on the full-size mirrors. The optical surface roughness in the mid-spatial and high-spatial ranges should meet the requirements in the Section 6.5.2. The specification for the surface figure is relaxed to only include a peak-valley surface height error of ≤ 158 nm (equivalent to λ/4 at 633 nm) over the central 80% of the coupon. These test coupons should be prepared and separately-delivered to SLAC as soon as feasible following the award of the contract, to expedite qualification of the reflective coating deposition process. Also note the packaging requirements outlined in Section 6.6.7.

6.6.4.2. Silicon Blank Substrate

The mirror substrate vendor shall provide one complete single-crystal silicon mirror substrate for verification of the SLAC mirror handling and mounting procedures, described in Section 9.1. This substrate should be prepared in the same manner as the primary mirror substrates. It should be cut to size, ground, prepared with the mounting holes and grooves, and wet-chemical etched with the other substrates. However, only relaxed specifications for figuring and polishing are required for the optical surface:. A peak-valley surface height error of ≤ 158 nm (equivalent to λ/4 at 633 nm) is required over the clear aperture, after subtraction of best-fit cylinder reference surfaces (see Sections

6.5.1 and Figure 6) with a mid-spatial and high spatial roughness of ≤ 1.0 nm rms (see Section 6.5.2). This test substrate should be separately-delivered to SLAC as soon as feasible, to expedite finalization of the mirror handling and mounting procedures.

6.6.5. Handling and Cleaning

6.6.5.1. Handling

Full, UHV handling practice is required. Each mirror shall be handled in accordance with the Handling and Process Plan, as reviewed and approved by SLAC.

6.6.5.2. Cleaning

Each mirror shall be cleaned at the mirror substrate vendor’s facility in a manner that is consistent with the figure, mid- and high-spatial frequency roughness requirements discussed in this section and that allows the mid- and high-spatial frequency roughness to be evaluated. Cleaning shall be performed at the mirror substrate vendor’s facility in accordance with the methods outlined in the Handling and Process Plan provided by the mirror substrate vendor and approved by SLAC.

6.6.6. Packaging and Shipping

The mirror substrate vendor shall be responsible for design and fabrication of the mirror shipping container(s). Best protection against contamination and shock/vibration is essential. An all-metal, dust-free interior-most enclosure is desirable. A brief description of proposed packaging and shipping arrangements shall be included in the Handling and Process Plan.

6.6.7. Test Coupon Packaging and Shipping

The mirror substrate vendor shall be responsible for supplying test coupon shipping container(s) for the test coupons described in Section 6.6.4.1. Best protection against contamination and shock/vibration is desirable. A dust-free interior, sealed enclosure is desirable. Coupons are to be restrained at the edges of the polished surface, to preserve the surface condition. A brief description of proposed packaging and shipping arrangements shall be included in the Handling and Process Plan.

6.6.8. Handling and Process Plan

All mirror processing shall take place in accordance with the methods described in the Handling and Process Plan supplied by the mirror substrate vendor. This document shall be provided in response to the Request for Proposal from SLAC, and must be reviewed and approved by SLAC. In that way, any materials compatibility issues for the completed mirrors can be identified and settled in advance. As noted in the sections above, the Handling and Process Plan shall include brief descriptions of the following:

(1) Fabrication process

(2) UHV handling procedures

(3) Mirror cleaning procedure

(4) Packaging and shipping arrangements

6.7. Quality Assurance Provisions

6.7.1. General

Prior to contract award, SLAC may perform a quality audit at the mirror substrate vendor’s facility to ascertain the existing or planned quality program implementation and procedures as it pertains to this procurement. Existing manufacturing procedures to be used for this procurement shall be reviewed during this audit.

The mirror substrate vendor shall maintain documentation for all metrology and processes during fabrication and characterization of these mirrors.

6.7.1.1. Program Management

The mirror substrate vendor shall actively manage all matters relating to the performance of this contract to ensure that all specifications, schedule, and quality objectives are fully met. A single individual shall be named to serve as the Program Manager of this subcontract. The Program Manager shall act as the single point of contact with SLAC on all technical and programmatic matters.

The subcontract shall establish and apply a program control system to track progress regarding pre-established, measurable milestones. The subcontract shall identify corrective management actions in the event shortfalls are detected or anticipated. The mirror substrate vendor shall develop and provide a detailed project schedule to SLAC. The schedule shall be periodically updated and provided at least on a monthly basis to SLAC as part of progress reporting.

In the event SLAC determines that the program success is in jeopardy because of technical, schedule, or quality shortfalls, SLAC reserves the right to conduct special program reviews and audits, as necessary, at the mirror substrate vendor’s facility.

6.7.1.2. Progress Reporting

SLAC and the mirror substrate vendor shall conduct, at a minimum, monthly status teleconferences. These teleconferences shall discuss general status of the program. Any item that has immediate effect on technical performance, schedule, or deliveries shall be brought to the immediate attention of SLAC.

6.7.1.3. Reviews

The vendor shall provide necessary support for an initial Technical Interface Meeting to discuss contract planning and to discuss any open contractual or technical action items.

6.7.1.4. Responsibility for Inspection and Tests

The responsibility for performing and documenting all specified tests and metrology shall rest with the mirror substrate vendor unless noted otherwise. The mirror substrate vendor shall submit an Inspection Test Procedure to SLAC for approval, as outlined in this document, describing each test or measurement to be implemented. SLAC reserves the right to perform in-process inspections at the mirror substrate vendor’s facility. The mirror substrate vendor shall notify SLAC a minimum of 5 working days prior to the start of final inspection and testing. Drawings and equipment that may be required for adequate inspection and test shall be made available to SLAC. SLAC inspection shall in no way relieve the mirror substrate vendor of responsibility for ensuring the quality of the mirrors.

6.7.1.5. Inspection Test Procedure

The mirror substrate vendor shall prepare an Inspection Test Procedure in response to the Request for Proposal from SLAC. It must be reviewed and approved by SLAC, and shall include the following at a minimum:

(1) Acceptance verification matrix that list each requirement (including pass/fail criteria) and indicate by what methods and procedures the mirror substrate vendor shall verify the requirement.

(2) Sequence of measurements, both in-process and final

(3) Equipment to be used

(4) Accuracy of measurements

(5) Calibration techniques

(6) Proposed data sheets of results and data format for the Inspection Test Report

6.7.1.6. In-Process Inspection Points

Mirror substrate vendor in-process inspection points shall be specified as part of the Inspection Test Procedure (see Section 6.7.1.5). At a minimum, inspections shall be performed at the following points:

(1) After initial shaping of the non-optical surface areas

(2) Selected points during mirror surface polishing

(3) Final inspection after the mirror is finished

6.7.2. Quality Conformance Inspections

6.7.2.1. Visual Inspection

The completed mirrors shall be visually inspected for conformance to the requirements in Section 6.6, prior to performing the measurements described in Section 6.7.2.2. If visual inspections uncover defects, additional inspections and measurements, as needed, shall be performed to determine acceptability. Visual inspections shall use techniques that enhance the visibility of defects, and shall be described in the Inspection Test Procedure (Section 6.7.1.5). Illumination of the surface shall be 200 or more foot-candles (lumens per square foot). The mirror shall be viewed against a dark background and from a direction just off the line of specular reflection.

Mirror polish shall be evaluated by visual inspection. Areas with scratches, or pits in excess of the requirements of Section 6.5 are unacceptable.

Optical surface edges shall be visually inspected for digs and chips.

Overall appearance shall be free from all visible contamination and poor workmanship indications.

6.7.2.2. Characterization Metrology

Compliance with the Optical Surface Quality Requirements specified in Section 6.5 shall be demonstrated through measurements, and the resulting data provided in the Inspection Test Report. As also stated in Section 6.7.1.5, all measurement procedures must be proposed in the Inspection Test Procedure and approved-by SLAC prior to execution.

Measurements shall be made under the following environmental conditions:

Temperature: 20°C ± 2°C.

Humidity: 30% to 70% relative humidity (RH)

During all measurements, the article under test and the test equipment shall be in thermal equilibrium within the specified temperature range.

Mid- and high-spatial frequency roughness shall be measured at the locations specified in Figure 6. These measurements shall be made after cleaning of the mirrors, as also discussed in Sections 6.5.2.and 6.6.4.

Instrumentation used for the measurement of figure, mid- and high- spatial frequency roughness should be capable of accurately measuring the spatial frequency bandwidths specified in Sections 6.5.1.and 6.5.2., respectively. All equipment should be in current and traceable calibration.

Figure 6: Location of roughness measurement sites, marked in blue. The clear aperture zone is marked in red.

6.7.3. Inspection Test Report

The mirror substrate vendor shall submit an Inspection Test Report of metrology results and associated raw data with each mirror at the time of delivery.

The Inspection Test Report shall include machine-readable raw data sets for all metrology performed. Data sets shall be in plain ASCII text, or another widely used format of mutual agreement. The mirror substrate vendor shall describe the file formats and supply necessary constants and parameters to permit independent data analysis of the raw data.

7. Coating Requirements

7.1. Coating Materials

Each mirror shall be coated with 2 reflective strips, each 5 mm wide. The first strip shall consist of a single layer of SiC.

The second strip shall consist of a bilayer. The bottom layer shall be a high atomic number material to be specified later by the SLAC group. The two likeliest candidate materials are Rhodium (Rh) and Ruthenium (Ru). The second layer material shall be Silicon Carbide (SiC).

The materials for each layer and each strip are listed in Table 3 and Table 4.

7.2. Coating Figure

The coating process of the mirrors shall preserve the figure of the polished Silicon substrates as described in Section 6. The figure error requirements listed in Table 3 and Table 4 shall not be exceeded after the coating is performed unless the mirror substrate that was delivered did not meet these specifications and a relaxed tolerance was agreed upon by the SLAC group.

Parameter Value Units Comment Coating material SiC Coating thickness 50 nm Figure height error <1.00 nm rms Over dimensions from 1mm to the clear aperture size Mid-spatial roughness

<0.25 nm rms Over the 10-3 to 0.5 µm-1 frequency range

High-spatial roughness

<0.25 nm rms Over the 0.5 to 50 µm-1 frequency range

Coating Strip width 5 mm Table 3: Mirror coating requirements for the first strip

First coating layer material

Rh or Ru

First coating layer thickness

30 nm

Figure height error (1st layer)

<1.00 nm rms Over dimensions from 1mm to the clear aperture size

Mid-spatial roughness (1st layer)

<0.25 nm rms Over the 10-3 to 0.5 µm-1 frequency range

High-spatial roughness (1st layer)

<0.25 nm rms Over the 0.5 to 50 µm-1 frequency range

Second coating layer material

SiC

Second coating layer thickness

20 nm

Figure height error (2nd layer)

<1.00 nm rms Over dimensions from 1mm to the clear aperture size

Mid-spatial roughness (2nd layer)

<0.25 nm rms Over the 10-3 to 0.5 µm-1 frequency range

High-spatial roughness (2nd layer)

<0.25 nm rms Over the 0.5 to 50 µm-1 frequency range

Coating Strip width 5 mm Table 4: Mirror coating requirements for the second strip

7.3. Coating Roughness

Roughness shall be measured on each mirror after deposition of each coating layer and strip. A visible-light interferometer or profilometer shall be used for mid-spatial frequency measurements at the coating vendor’s facility. If available, an AFM instrument shall be used for high-spatial frequency measurements at the coating vendor’s facility. If an AFM instrument is unavailable, alternative arrangements must be made by the coating vendor.

Verification of the mid-spatial frequency roughness and the high-spatial frequency roughness will be performed by a third party with white-light optical profiling microscope and AFM capabilities as described in Section 8 after the coating process has been completed.

7.4. Workmanship

Workmanship shall be consistent with the quality necessary for stable operation of sensitive optical devices under long-term exposure to an x-ray, ultrahigh vacuum (UHV) environment similar to that found in synchrotron radiation user facilities.

7.5. Process Development

The coating vendor shall develop and test the coating process on test substrates before coating the final mirrors. These test substrates can consist of small thin silicon wafers. The coating vendor shall fully characterize the test coatings in a manner consistent with the final metrology to be performed on the real mirrors and the results shall be communicated to SLAC prior to proceeding with the coating of the mirrors. SLAC shall make available some of the test coupons provided by the mirror substrate vendor for the coating process development.

7.6. Handling and Cleaning

7.6.1. Handling

Full, UHV handling practice is required. Each mirror shall be handled in accordance with the Handling and Coating Process Plan described in Section 0, as reviewed and approved by SLAC.

7.6.2. Cleaning

Each mirror shall be cleaned at the coating vendor’s facility in a manner that is consistent with the figure, mid- and high-spatial frequency roughness requirements discussed in this document, as well as the coating, and that allows the mid- and high-spatial frequency roughness to be evaluated. Cleaning shall be performed at the coating vendor’s facility in accordance with the methods outlined in the Handling and Coating Process Plan provided by the vendor and approved by SLAC, as described in Section 0.

7.7. Packaging and Shipping

The coating vendor shall utilize the same packaging and shipping procedure as the mirror substrate vendor as outlined in the Handling and Process Plan described in Section 6.6.8.

The plan developed by the mirror substrate vendor will be communicated to the coating vendor by the SLAC group and the coating vendor is expected to follow this plan or submit its own plan to be approved by SLAC.

7.8. Test Coupon Packaging and Shipping

The coating vendor shall utilize the same packaging and shipping procedure for the test coupons as the mirror substrate vendor as outlined in the Handling and Process Plan described in Section 6.6.8. The plan developed by the mirror substrate vendor will be communicated to the coating vendor by the SLAC group and the coating vendor is expected to follow this plan or submit its own plan to be approved by SLAC.

7.9. Handling and Coating Process Plan

All mirror coating processes shall take place in accordance with the methods described in the vendor-supplied Handling and Coating Process Plan. SLAC will provide to the coating vendor the Handling and Process Plan supplied by the mirror substrate vendor (described in Section 6.6.8 and the coating vendor is expected to follow this plan or submit its own plan to be approved by SLAC. Also, an addendum to this plan shall be provided by the coating vendor to include a brief description of the mirror coating procedures. This addendum shall be provided in response to the Request for Proposal from SLAC, and must be reviewed and approved by SLAC. In that way, any materials compatibility issues for the completed mirrors can be identified and settled in advance.

7.10. Quality Assurance Provisions

7.10.1. General

Prior to contract award, SLAC may perform a quality audit at the coating vendor’s facility to ascertain the existing or planned quality program implementation and procedures as it pertains to this procurement. Existing procedures to be used for this procurement shall be reviewed during this audit.

The coating vendor shall maintain documentation for all metrology and processes during coating and characterization of these mirrors.

7.10.1.1. Program Management

The coating vendor shall actively manage all matters relating to the performance of this contract to ensure that all performance, schedule, and quality objectives are fully met. A single individual shall be named to serve as the Program Manager of this subcontract. The Program Manager shall act as the single point of contact with SLAC on all technical and programmatic matters.

The subcontract shall establish and apply a program control system to track progress regarding pre-established, measurable milestones. The subcontract shall identify corrective management actions in the event shortfalls are detected or anticipated. The coating vendor shall develop and provide a detailed milestone schedule to SLAC.

In the event SLAC determines that the program success is in jeopardy because of technical, schedule, or quality shortfalls, SLAC reserves the right to conduct special program reviews and audits, as necessary, at the coating vendor’s facility.

7.10.1.2. Progress Reporting

SLAC and the coating vendor shall conduct, at a minimum, twice monthly status teleconferences. These teleconferences shall discuss general status of the program. Any item that has immediate effect on technical performance, schedule, or deliveries shall be brought to the immediate attention of SLAC.

7.10.1.3. Reviews

The vendor shall provide necessary support for an initial Technical Interface Meeting to discuss contract planning and to discuss any open contractual or technical action items.

7.10.1.4. Responsibility for Inspection and Tests

The responsibility for performing and documenting all specified tests and metrology shall rest with the coating vendor unless noted otherwise. The coating vendor shall submit a Coating Inspection Test Procedure to SLAC for approval, as outlined in this document, describing each test or measurement to be implemented. SLAC reserves the right to perform in-process inspections at the coating vendor’s facility. The coating vendor shall notify SLAC a minimum of 5 working days prior to the start of final inspection and testing.

Drawings and equipment that may be required for adequate inspection and test shall be made available to SLAC. SLAC inspection shall in no way relieve the coating vendor of responsibility for ensuring the quality of the mirrors.

7.10.1.5. Coating Inspection Test Procedure

The coating vendor shall prepare a Coating Inspection Test Procedure in response to the Request for Proposal from SLAC. It must be reviewed and approved by SLAC, and shall include the following at a minimum:

(1) Acceptance verification matrix that list each requirement (including pass/fail criteria) and indicate by what methods and procedures the mirror substrate vendor shall verify the requirement.

(2) Sequence of measurements, both in-process and final

(3) Equipment to be used

(4) Accuracy of measurements

(5) Calibration techniques

(6) Proposed data sheets of results and data format for the Coating Inspection Test Report

7.10.1.6. In-Process Inspection Points

Vendor in-process inspection points shall be specified as part of the Coating Inspection Test Procedure (see Section 7.10.1.5). At a minimum, inspections shall be performed at the following points:

(1) Upon receipt of the mirror substrate

(2) After deposition of the each layer and each strip

(3) Final inspection after the mirror coating is finished

7.10.2. Quality Conformance Inspections

7.10.2.1. Characterization Metrology

Compliance with the Optical Surface Quality Requirements specified in Sections 7.2 and

7.3 shall be demonstrated through measurements, and the resulting data provided in the Coating Inspection Test Report. As also stated in Section 7.10.1.5, all measurement procedures must be proposed-to and approved-by SLAC prior to execution.

Measurements shall be made under the following environmental conditions:

Temperature: 20°C ± 2°C.

Humidity: 30% to 70% relative humidity (RH)

During all measurements, the article under test and the test equipment shall be in thermal equilibrium within the specified temperature range.

Mid- and high-spatial frequency roughness shall be measured at the locations specified in Figure 6. These measurements shall be made after each layer has been deposited on the mirrors.

Instrumentation used for the measurement of figure, mid- and high- spatial frequency roughness should be capable of accurately measuring the spatial frequency bandwidths specified in Table 3. All equipment should be in current and traceable calibration.

7.10.3. Coating Inspection Test Report

The coating vendor shall submit a Coating Inspection Test Report of metrology results and associated raw data with each mirror at the time of delivery.

The Coating Inspection Test Report shall include machine-readable raw data sets for all metrology performed. Data sets shall be in plain ASCII text, or another widely used format of mutual agreement. The coating vendor shall describe the file formats and supply necessary constants and parameters to permit independent data analysis of the raw data.

7.11. Test Coupons

Test coupons will be provided by the substrate vendor as described in Section Error!

Reference source not found.. These test coupons will be provided to the coating vendor for qualification of the coating process. The coating vendor shall use the test coupons to develop the coating procedure in the way that it sees fit and communicate the results to SLAC prior to proceeding with the coating of the mirrors.

8. Metrology Requirements

The surface properties of the mirrors shall be characterized at various stages of the fabrication process. This section outlines the specifications for metrology to be performed on the 2 mirrors described in Sections 6 and 7.

8.1. Frequency of Measurements

The metrology measurements described in Section 8 shall be performed after the delivery of the mirror substrates by the substrate vendor, described in Section 6, after the deposition of the first coating strip described in Section 7 and after the deposition of the second coating strip also described in Section 7. Additionally, metrology shall be performed on the test coupons provided by the substrate vendor as described in Section 6.

The metrology to be performed on the test coupons shall include only the measurements of the mid and high spatial roughness.

8.2. Figure Measurements

Long-trace profilometry or stitching interferometry shall be used to determine the surface figure at the metrology vendor’s facility. All roughness and slope errors shall be determined after subtraction of best-fit elliptical reference surface from the clear aperture zone.

8.3. Roughness Measurements

A visible-light interferometer or white-light optical profiling microscope shall be used for mid-spatial frequency measurements at the metrology vendor’s facility. An AFM instrument shall be used for high-spatial frequency measurements at the metrology vendor’s facility. The spatial frequency ranges required for the measurements are described in Table 1, Table 2 and Table 3. The metrology vendor must be capable of performing measurements over all these spatial frequencies.

Mid- and high-spatial frequency roughness shall be measured at the locations specified in Figure 6.

8.4. Power Spectral Density

All the metrology results shall be combined into a Power Spectral Density (PSD) plot showing the surface height fluctuations over the entire spatial frequency range of the measurements. This shall be provided to SLAC in the Metrology Report.

8.5. Workmanship

Workmanship shall be consistent with the quality necessary for stable operation of sensitive optical devices under long-term exposure to an x-ray, ultrahigh vacuum (UHV) environment similar to that found in synchrotron radiation user facilities.

8.6. Handling

Full, UHV handling practice is required. Each mirror shall be handled in accordance with the Handling and Process Plan described in Section 6.6.8. This plan shall be supplied by SLAC to the metrology vendor and the metrology vendor is expected to follow this plan or submit its own plan to be approved by SLAC.

8.7. Packaging and Shipping

The metrology vendor shall utilize the same packaging and shipping procedure as the mirror substrate vendor as outlined in the Handling and Process Plan described in Section

6.6.8. The plan developed by the mirror substrate vendor will be communicated to the metrology vendor by the SLAC group and the metrology vendor is expected to follow this plan or submit its own plan to be approved by SLAC.

8.8. Handling and Metrology Process Plan

All mirror metrology processes shall take place in accordance with the methods described in the Handling and Metrology Process Plan supplied by the metrology vendor. SLAC will provide to the metrology vendor the Handling and Process Plan supplied by the mirror substrate vendor (described in Section 6.6.8) and the metrology vendor is expected to follow this plan or submit its own plan to be approved by SLAC. Also, an addendum to this plan shall be provided by the metrology vendor to include a brief description of the mirror metrology procedures. This addendum shall be provided in response to the Request for Proposal from SLAC, and must be reviewed and approved by SLAC.