MPEX-07-SRD-001-R2-final.pdf

MPEX-07-SRD-001-R2

Systems Requirements Document for the Diagnostics System

MATERIAL PLASMA EXPOSURE EXPERIMENT

(MPEX)

Prepared by

OAK RIDGE NATIONAL LABORATORY

Oak Ridge, TN 37831-6283 Managed by

UT-BATTELLE, LLC

For the

US DEPARTMENT OF ENERGY

under contract DE-AC05-00OR22725

This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof.

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Material Plasma Exposure Experiment Oak Ridge National Laboratory

Systems Requirements Document for the Diagnostics System

Material Plasma Exposure Experiment Project

MPEX-07-SRD-001

Date

Date

Date

Date

Date

Date

Date

Theodore Biewer, Reviewer Section 2.2, 2.6, 4.2, 4.6

Ted Boyd, Reviewer

Diego De Oliveira Omitto, Reviewer

Drew Elliott, Reviewer Section 2.8, 4.8

Keisuke Fujii, Reviewer Section 2.3, 2.4, 4.3, 4.4

Travis Gray, Reviewer Section 2.5, 2.7, 4.5, 4.7

Xiao Ying Yu, Reviewer Section 3.2.3

Erik Swensen, Reviewer Date

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Aftab Hussain, Lead Engineer / Reviewer Date

Milena Keys, Quality Assurance Representative / Reviewer Date

Craig Deibele, Diagnostics CAM Date

Distribution:

Phil Ferguson, Project Director / Information Juergen Rapp, Chief Scientist / Information Robyn Rose, Project Manager / Information

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Material Plasma Exposure Experiment Project

MPEX-07-SRD-001

Revision History

Revision Date DESCRIPTION OF CHANGE

REVISION TYPE

Major Minor

0 7/28/21 Initial Issue ☒ ☐

1 12/8/21 Add RMS to ACRONYMS. Revise text to active voice, shall instead of will for 701.030-I, 701.031-I, 701.032-I, 701.033-I, 701.001-R, 701.002-R, 701.003-R, 701.004-R, 701.005-R, 701.110-R, 701.111-R, 701.005-I, 701.006-R, 701.007-R, 701.008-R, 701.009-R, 701.010-R, 701.011-R, 701.012-R, 701.013-R, 701.061-R, 701.062-R, 701.076-R, 701.077-R, 701.063-R, 701.064-R, 701.065-R, 701.066-R, 701.067-R, 701.068-R, 701.069-R, 701.016-R, 701.017-R, 701.018-R, 701.040-R, 701.041-R, 701.042-R, 701.043-R, 701.044-R, 701.045-R, 701.046-R, 701.047-R, 701.048-R, 701.049-R, 701.058-R, 701.059-R, 701.060-R, 701.055-R, 701.020-R, 701.021-R, 701.022-R, 701.023-R, 701.078-R, 701.079-R, 701.080-R, 701.081-R, 701.082-R, 701.083-R, 701.052-R, 701.056-R, 701.051-R, 701.051-R, 701.057-R, 701.084-R. Delete second half of 701.013-R and insert in 701.014-R to replace text related to

MPEX-07-SRD-001-R2 Page 5 of 102 operational plan. Delete 701.015-R, 701.071-R, 701.050-R, 701.053-R, 701.054-R. Eliminate TBDs in 701.061-R, 701.069-R. Shall replaces will in 701.019-R. Add requirements 701.112-R, 701.113-R, 701.114-R, 701.115-R, 701.116-R.

Add new recommendation for 2.1 and delete sentence for PR317-R.

Add subsections 2.a and 2.b. In Table 1, revise range for Target Surface imaging and delete Target Surface erosion. Plasma dynamics, ñ was Dalpha. Role 2.a was 2 for Soft X-ray monitoring, Radiated power, Plasma dynamics, Electron Temperature profile, Electron Density profile, Ion Temperature profile, Plasma Flow, Impurity Species Monitoring (nZ and PZ). Role 2.b was 2 for Neutral Gas density, Target Surface imaging.

Table 2, delete SETC row.

2 1/4/23 Section 1.2: Add terminology and definitions text formerly in Section

1.4. Delete Section 1.4. Section 2.1:

Delete reference to table and requirement 701.016-R. 701.030-I:

“will” was “shall”. 701.031-I: “will” was “shall”. 701.032-I: add “be”.

701.008-R: “temporally resolved measurements to” was “temporal requirements measurements”.

701.010-R: “radially resolved” was “radial”. 701.011-R: “azimuthally resolved” was “azimuthal requirements”. 701.012-R: “axially resolved” was “axial requirements”.

Section 3.1.5: Add text to replace “N/A”. Add sections 701.117-R and 701.118-R. Table 1: Delete rows for “Magnetic field (SC windings)”, “Magnetic field (Cu windings)”, and

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“Total Neutral Gas pressure”. Table 2: Delete row for “Magnetics”.

Table 2; Optical: Add ECH to Thomson Scattering location; Delete ICH from Laser Interferometer location; Revise Survey Spectroscopy hierarchy to backup from primary; Revise High Resolution Spectroscopy hierarchy to primary from backup; Revise Filterscopes Location to 10 from 50;

Delete ICH from Bolometry location;

Delete Pressure/Baratrons from table; Delete Pressure/LIDS,LIAS from table; Add Temperature/Fluoroptic Probe to table. Delete 701.040-R. Delete 701.045-R. Delete 701.049-R. Table B-2: Delete Baratron from Diagnostics content and add Vacuum content to contain Baratron. (7 places)

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TABLE OF CONTENTS

1 SCOPE

1.1 DOCUMENT OVERVIEW

1.1 TERMINOLOGY AND DEFINITIONS

1.2 INCOMPLETE AND TENTATIVE REQUIREMENTS

2 FUNCTIONS

2.1 SYSTEM FUNCTIONS

2.2 SYSTEM BASIC CONFIGURATION: DRGA

2.2.1 Description

2.2.2 Design Considerations

2.2.3 Design Overview

2.2.4 Steady-State Strategy

2.2.5 Maintenance Plan

2.2.6 Process flow diagram

2.2.7 Bake-out Considerations

2.3 SYSTEM BASIC CONFIGURATION: HIRES-OES

2.3.1 Description

2.3.2 Design Overview

2.3.3 System Requirements

2.3.4 Camera

2.3.5 Software Requirements

2.3.6 Environmental Requirements

2.4 SYSTEM BASIC CONFIGURATION: VISIBLE CAMERA

2.4.1 Design Overview

2.4.2 Requirements

2.4.3 Instrument Requirements

2.4.4 Measurement Locations

2.4.5 Software and Control Requirements

2.5 SYSTEM BASIC CONFIGURATION: INFRARED CAMERA

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2.5.1 Measurement Requirements

2.5.2 Physical Requirements

2.5.3 Optical Requirements

2.5.4 Calibration Requirements

2.5.5 Measurement Locations

2.5.6 Interface with I&C

2.5.7 Interface with Vacuum Systems and Cooling Systems

2.6 SYSTEM BASIC CONFIGURATION: MICROWAVE DETECTORS

2.6.1 Description

2.6.2 Design Considerations

2.6.3 Installation Locations

2.6.4 EMI Requirements

2.6.5 On Device Diagnostics Requirements

2.6.6 Electrical and Mechanical Requirements

2.7 SYSTEM BASIC CONFIGURATION: PYROMETERS

2.7.1 Description

2.7.2 Design Considerations

2.7.3 Design Overview

2.7.4 Steady-State Strategy

2.7.5 Maintenance Plan

2.7.6 Locations of Pyrometer

2.7.7 Measurement Requirements

2.7.8 Physical Requirements

2.7.9 Optical Requirements

2.7.10 Calibration Requirements

2.7.11 I&C Interface

2.8 SYSTEM BASIC CONFIGURATION: THOMSON SCATTERING

2.8.1 Project Level Requirements

2.8.2 MEASUREMENT REQUIREMENTS

2.8.3 Laser System

2.8.4 Light Transport and Collection

2.8.5 Analysis and Control

2.8.6 Control

2.8.7 Assembly, Calibration, and Commissioning

2.9 SYSTEM INTERFACES

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3 DESIGN REQUIREMENTS

3.1 GENERAL REQUIREMENTS

3.1.1 Facility Locations

3.1.2 Use of Diagnostics for Plasma Control

3.1.3 Use of Diagnostics for Measuring Key Performance Parameters

3.1.4 Spatial and Temporal Requirements on Diagnostics

3.1.5 Diagnostic Window Transmission Assessment

3.1.6 Hazard implications associated with Diagnostics

3.2 SYSTEM SPECIFIC REQUIREMENTS

3.2.1 MPEX on-device Diagnostics Systems

3.2.2 Specific MPEX on-device Measurements

3.2.3 MPEX off-device Diagnostics Systems (Surface Analysis Diagnostics)

3.3 MECHANICAL REQUIREMENTS

3.4 ELECTRICAL REQUIREMENTS

3.5 GROUNDING AND INSULATION REQUIREMENTS

3.6 INSTRUMENTATION AND CONTROL REQUIREMENTS

3.7 COMPUTER HARDWARE AND SOFTWARE REQUIREMENTS

3.8 VACUUM REQUIREMENTS

3.9 THERMAL MANAGEMENT REQUIREMENTS

3.10 ASSEMBLY REQUIREMENTS

3.11 INSTALLATION REQUIREMENTS

3.12 TESTING AND INSPECTION REQUIREMENTS

4 ENGINEERING DERIVED REQUIREMENTS

4.1 GENERAL REQUIREMENTS

4.2 DRGA REQUIREMENTS

4.3 OES-HIRES REQUIREMENTS

4.4 VISIBLE CAMERA REQUIREMENTS

4.5 INFRARED CAMERA REQUIREMENTS

4.6 MICROWAVE DETECTOR REQUIREMENTS

4.7 PYROMETER REQUIREMENTS

4.8 THOMSON SCATTERING REQUIREMENTS

4.9 WINDOW/PERISCOPE REQUIREMENTS

5 QUALITY ASSURANCE PROVISIONS

5.1 GENERAL REQUIREMENTS

6 APPENDIX A RELAVENT PROJECT REQUIREMENTS

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7 APPENDIX B

8 REFERENCES

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Diagnostics Systems

ACRONYMS

3D three-dimensional

ALARA as low as reasonably achievable

AMU Atomic Mass Unit

ANSI American National Standards Institute

CA contamination area

CCD Charge Coupled Device

CD Critical Decision

CIS Central Interlock System

CMM Configuration Management Model

CVD Chemical Vapor Deposition

CWS cooling water system

D&D decontamination and decommissioning

DESO division electrical safety officer

DLSO division laser safety officer

DRGA diagnostic residual gas Analyzer

EBW electron Bernstein wave

EC electron cyclotron

ECH Electron Cyclotron Heating

EDX energy-dispersive x-ray analysis

EMI Electromagnetic Interference

EPD electronic pocket dosimeter

ES&H environmental, safety, and health

FIB focused ion beam

HAR Hazard Analysis Report

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HEPA high-efficiency particulate arrestance

I&C instrumentation and control

IC ion cyclotron

ICCD Intensified Charge Coupled Device

ICH Ion Cyclotron Heating

IOC Input Output Controller

IR Infrared ke- thousand electron

KPP Key Performance Parameter

LIBS laser-induced breakdown spectroscopy

LIDT Laser Induced Damage Threshold

LPD linear plasma device

LSM laboratory space manager

LTM long-term maintenance

LTV lock/tag/verify

MPEX Material Plasma Exposure eXperiment

NPP Nominal Performance Parameter

NRA nuclear reaction analysis

NRPD Nuclear and Radiological Protection Division

ORNL Oak Ridge National Laboratory

P&ID piping and instrumentation diagram

PLC programmable logic controller

PMI plasma material interaction

PR Project Requirements document

QAPP Quality Assurance Project Plan

QHSP qualified health and safety professional

RA radiation area

RAMI reliability, availability, maintainability, and inspectability

RBA radiological buffer area

RCT radiological control technician

RF radio frequency

RGA residual gas analyzer

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RGD radiation-generating device

RMS Root Mean Square; i.e., the square root of the mean value of the quadratic square of a series of a values

RSS Research Safety Summary

RWP radiological work permit

S&T science and technology

SAS surface analysis station

SBMS Standards-Based Management System

SEM scanning electron microscope

SMA Fiber Optic Connector Standard IEC 61754-22

SNR signal to noise ratio

SOP standard operating procedure

SRD System Requirements Documents

SSC structures, systems, or components

STM short-term maintenance

TBC to be confirmed

TBD to be determined

TEC target exchange chamber

TS Thomson scattering

UPP Ultimate Performance Parameter

VQM Vacuum Quality Monitor

WBS Work Breakdown Structure

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1 SCOPE

The Diagnostics system covers all diagnostics for the scientific exploration of the Materials Plasma Exposure eXperiment (MPEX). These include diagnostics which are needed for machine protection as well as basic and advanced machine control. Surface analysis diagnostics co-located with the MPEX facility, which may be utilized to examine material samples after plasma exposure, are also included in this subsystem.

1.1 DOCUMENT OVERVIEW

This document, the System Requirements Document (SRD) for the Diagnostics (WBS #07), is the complete development specification for this system. The specification approach being used on MPEX provides for a clear distinction between performance requirements and design constraints.

Performance requirements state what functions a system must perform and how well that function has to be performed. Design constraints, on the other hand, are a set of limiting or boundary requirements that must be adhered to while allocating requirements or designing the system.

Constraints are drawn from externally imposed sources (e.g., statutory regulations, DOE Orders, and ORNL ES&H Directives) as well as from internally imposed sources as a result of prior decisions, which limit subsequent design alternatives.

This document restates (for convenience) many Project Requirements which specifically pertain to the Diagnostics subsystem. Moreover, additional Diagnostics subsystem requirements are given in this document.

1.1 TERMINOLOGY AND DEFINITIONS

Use of the words “shall”, “should”, “may”, and “will”. The words shall, should, may, and will have the following specific meanings in the context of this document: shall is used wherever a provision is mandatory (it is a requirement); should is used wherever it is necessary to express recommended provisions; may is used to express allowed provisions (both are treated as potentialities); and will is used to express a declaration of purpose. It may also be necessary to use will in cases where the simple future tense is required. [PR28-I] Abbreviations and acronyms. Abbreviations and acronyms are used consistently throughout, without definition. A glossary of such abbreviations and acronyms can be found in the front matter.

[PR30-I]

Each paragraph of the Project Requirements (PR) is then classified as being either a Requirement, a design Constraint, a Potentiality or Information. The paragraph identifier, and its classification (R, C, P or I), is indicated at the end, in square brackets. (For example, this paragraph has the identifier PR32, and is for information). [PR32-I] Where Project Requirements are repeated in this document, they will use the PR identifiers previously given.

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Each requirement in the SRD has a unique and permanent identifier. Each requirement is classified as being either a Requirement, a design Constraint, a Potentiality or Information (R, C, P or I). The requirement identifier is indicated at the beginning of the requirement, in square brackets. The convention for requirements identifiers is:

[XYY.ZZZ-L]

where:

• X is the WBS (7 for 07 Diagnostics Systems)

• YY is the last two digits of the SRD document number. YY=01 for this document, (MPEX-07-SRD-001).

• ZZZ is the sequential number for the requirement

• L is the classification (R, C, P or I)

[701.001-I] System Requirements associated with Diagnostics WBS #7 will be labeled as 701.zzz- R. The paragraph identifier, and its classification (R, C, P or I), is indicated at the beginning, in square brackets. (For example, this paragraph has the informational identifier 701.001-I).

1.2 INCOMPLETE AND TENTATIVE REQUIREMENTS

Use of the terms TBD and TBC, if any. Within this document, the term “to be determined” (TBD) applied to a missing or incomplete requirement infers that additional effort (such as analysis) is required before the requirement can be completely specified. The term “to be confirmed” (TBC) implies that the requirement may be reviewed for appropriateness by the project and changed during the project development. [PR29-I]

2 FUNCTIONS

2.1 SYSTEM FUNCTIONSFor the MPEX Project, the basis for having a Diagnostics System is shown in this section with these listed MPEX Project Requirements. These Project Requirements listed are the justification of the MPEX Diagnostics system rather than specifically driving Diagnostics System design.

In general, the diagnostics systems will perform their roles during plasma operations to maintain control of the discharge and provide for safe operating conditions.

Specific measurement requirements on diagnostic subsystems are given in the following tables.

Measurements for MPEX diagnostics have four possible roles.

• Machine protection (1.a1)

• Basic machine control (1.a2)

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- An example would be preprogrammed (“passive”) operational scenarios of the helicon plasma source with auxiliary heating sources at 0–50% power capability.

• Advanced plasma control (1.b)

- Examples would be active-feedback operational scenarios, or pre-programmed operational scenarios with auxiliary heating sources at 50–100% power capability.

• Evaluation and physics studies (2.)

o Plasma physics evaluation and heating physics evaluation (2.a) o PMI science (2.b)

[PR318-I]

MPEX will not operate plasma discharges without a working diagnostic providing every measurement for machine protection (1.a1 role).

MPEX will/should (TBC) not operate basic plasma discharges without a working diagnostic providing every measurement for basic control (1.a2 role).

MPEX should not operate advanced scenarios without a working diagnostic providing every measurement for advanced plasma control (1.b role).

MPEX may operate even when a measurement for evaluation and physics studies (2. Role) is not provided.

According to their technologies, MPEX diagnostics systems may have different contributions to different measurements. The following contributions should be considered:

Primary: diagnostic is well suited to the measurement Backup: diagnostic provides similar data to primary but has some limitations Supplementary: diagnostic validates or calibrates the measurement but is not complete in itself

[PR324-R]

2.2 SYSTEM BASIC CONFIGURATION: DRGA

The basic configuration of the Diagnostic Residual Gas Analyzer (DRGA) is described in [1].Sections of this document are repeated here.

2.2.1 Description

The DRGAs will provide measurements of the partial pressure of gasses present in the MPEX device, between and during plasma discharges. When measurements are made between discharges, the RGA instrumentation can be said to be operating as a vacuum quality monitor (VQM). Many commercial off-the-shelf (COTS) RGAs are available to provide VQM measurements. Operation of an RGA to produce measurements during plasma discharges is

MPEX-07-SRD-001-R2 Page 17 of 102 referred to as a Diagnostic RGA (DRGA) and is a technique that has been developed at ORNL for fusion applications. Commercially available RGAs are available with a variety of features. See papers by Biewer, Klepper regarding the detailed design of DRGAs for during-plasma discharge measurements.

2.2.2 Design Considerations

DRGA measurements, i.e., during plasma operations (a.k.a. in operando), must overcome environmental conditions not experienced by RGA’s operating as VQMs, i.e., between plasma discharges (a.k.a. in situ). In the MPEX context, these in operando environmental constraints are largely associated with elevated neutral gas pressure in the device, high background magnetic field, and potential Electromagnetic Interference (EMI) from auxiliary power systems. Moreover, for fusion-relevant applications, the partial pressures of low-mass gasses (1-6 amu) are of particular interest and can be complicated by mass-overlap of certain isotopic combinations (e.g., HD molecules and T atoms are both mass 3 Atomic Mass Unit (amu); D2 molecules and He atoms are both mass 4 amu; etc.).

2.2.3 Design Overview

Figure 2.2-1. Schematic of the diagnostic layout of MPEX

There are currently 2 separate DRGA systems planned for utilization on MPEX. The design of the DRGAs is based on prototype systems which were designed and tested for US ITER, with hardware implemented on JET, W7X, and Proto-MPEX. Each of these systems has unique requirements. The DRGA system for MPEX will be comprised of components similar to that used on Proto-MPEX, as shown in Figure 2.2-2.

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Figure 2.2-2. The DRGA cart on the dump tank of Proto MPEX

The MPEX DRGAs will be located at the dump tank at the upstream end of the device, and downstream of the PMI chamber (upstream of the TEC autocoupler). Each DRGA consists primarily of a movable cart that supports a small turbo-molecular pump station. The measurement instrumentation “tree” is mounted to the inlet side of the turbo pump. The planned instrumentation includes one or more total-pressure gauge (TPG), a quadrupole mass spectrometer (QMS) RGA, and an optical Penning gauge (OPG) or equivalent for optical gas analysis (OGA). Gas is sampled from MPEX on a designated port (with isolation valve) via a conductance limiting aperture, typically accomplished by a needle valve or a metering valve in-line with a length of flexible tubing. An additional isolation valve may be incorporated downstream of the needle-valve, so as to be able to remove the DRGA from MPEX while maintaining vacuum in both MPEX and the DRGA. In this configuration the vacuum base pressure in the DRGA will typically be lower than in the MPEX device by 1-2 orders of magnitude.

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Figure 2.2-3. The DRGA cart downstream of the PMI chamber of MPEX

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Figure 2.2-4. The DRGA cart on the dump tank of MPEX

2.2.4 Steady-State Strategy

There is no inherent limit to operating the DRGAs indefinitely. This is routinely done on many facilities.

Regular maintenance is considered part of a reliable, steady-state operation strategy.

2.2.5 Maintenance Plan

The major items of the system that will require maintenance include: the RGA filaments, the roughing pumps and the turbo-molecular pumps.

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RGA: These units are COTS, and the maintenance requirements set by the vendor should be followed.

2.2.6 Process flow diagram

Figure 2.2-5. DRGA process flow diagram

The DRGA system carts will be located in the MPEX area, adjacent to the MPEX device. These carts will receive 120 V-AC power from outlets in the machine area. Instrumentation signals (electrical and optical) will route from the machine area to the interface racks located in the Pit area. Instrumentation signals will be further routed (via the embedded conduits) from the Pit racks to racks in the Diagnostic Hall. Intermediate processing of RGA signals may occur at a workstation running vendor supplied software. Processed data will then be routed to I&C for utilization and archiving. Light emission signals will be routed from the Pit to spectrometers in the Diagnostic Hall by dedicated optical fiber (via the embedded conduits). Spectroscopic data may be processed at a workstation running vendor supplied software. Processed data will then be routed to I&C for utilization and archiving.

Control signals from I&C will be routed (via the embedded conduits) to I&C racks in the Pit and subsequently to the DRGA systems.

2.2.7 Bake-out Considerations

The MPEX vacuum vessel (VV) and in-vessel components (IVC) are being designed to meet the requirement of a 150 C bake-out. The specific requirements (e.g., frequency, duration, effected

MPEX-07-SRD-001-R2 Page 22 of 102 components, etc.) of the bake are given elsewhere. Computational fluid dynamic (CFD) calculations indicate the ambient air temperature between the VV and the magnet cryostat (e.g., in the PMI chamber region) should be 50 C or less during the bake, with forced air circulation. Since diagnostic system components are in some instances part of the vacuum boundary, or closely adjacent to it, there is the potential for diagnostic components to experience significantly elevated temperatures during the bake. Note: during normal operations the MPEX VV is actively cooled with water at 30 C (85 F). Consequently, the diagnostic components in contact with the VV or in the space between the VV and cryostat, should not experience excessive temperature rises during normal operations. This subsection for each diagnostic system will describe the bake-out considerations for specific diagnostic components.

The DRGA instrumentation will sit adjacent to the MPEX device, outside the magnet cryostats.

Hence the instrumentation will not be directly affected by the bake.

Components in direct contact with the VV ports (<150 C):

Sample pipe and aperture: The process gasses from MPEX will be drawn to the DRGA stations via a sample pipe and conductance-limiting aperture. These are standard vacuum components which are all-metal and bakeable.

2.3 SYSTEM BASIC CONFIGURATION: HIRES-OES

2.3.1 Description

The High-Resolution Optical Emission Spectroscopy (HiRes-OES) will provide the ion temperature and flow velocity in plasmas. This diagnostic is based on the assumption that the bulk ions (deuterium ion) and impurity ions (e.g., singly charged argon) are in local thermal equilibrium. The impurity ions emit light, and the line emission is broadened reflecting their thermal movement according to Doppler effect. The (main) ion temperature will be estimated from the broadening of the line, and the ion flow will be estimated from the shift of the line from the rest wavelength, both of which will be obtained by high-resolution spectroscopic measurements.

One of the KPP of the MPEX project is to achieve plasma with ion temperature at the target ≥ 5 eV.

HiRes-OES shall provide this information.

The dominant factors that generally limit the measurement accuracy is a) limited number of photon due to the low concentration of partially ionized plasma particles, b) another broadening mechanism (mostly Zeeman effect) of the emission line, and c) limited wavelength resolution of the instruments (i.e., spectrometer).

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A general challenge to the ion temperature / flow measurement is the temporal drift of the instrumental property. Since by vibration or thermal expansion of any parts, some slight misalignment of the optical parts in the spectrometer is expected, which significantly affects the measurement accuracy. Constant monitoring of the alignment may be required and is experimentally determined.

A challenge specific to MPEX environment is steady-state operation. Typical spectroscopic measurements start from the image acquisition by the detector, the data is transferred to the computer after all the acquisition finished, and the data is processed to estimate the required quantity, i.e., all the processes are sequential. However, as the MPEX experiment will last more than 30 min, near real-time and parallel operation (data streaming from the camera during the acquisition, data analysis, data transfer) may be required.

2.3.2 Design Overview

Figure 2.3-1. A schematic illustration of the high-resolution spectroscopy system.

This system measures the spectral broadening of impurity ion emission from MPEX and to obtain the volume averaged temperature from the broadening.

The system consists of light collection lenses, optical fibers, a spectrometer, a camera, and personal computer to control the data acquisition and to analyze the signal (Figure 2.3-1). The light from several ports on MPEX are introduced into optical fibers and transferred to spectroscopic systems.

The exposure timing of the camera is controlled by a timing signal. The raw data and the analyzed data are sent to a network storage.

Two sets of spectroscopic systems (spectrometer, camera, computer, calibration lamp) shall be prepared; one is used for the routine measurement and expected to provide a standard quantity (the main system), while the other is considered as backup and used for more flexible purposes, such as for the cross check with another impurity temperature and special requests by users (the backup system). Each spectrometer can measure spectra from ~7 locations.

The calibration lamp shall be integrated into a system. Once one experiment terminated, the system shall be calibrated by measuring the light from the calibration lamp by the same spectrometer. This is essential to accurately estimate the wavelength resolution of the instruments.

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2.3.3 System Requirements

There are explicit requirements from scientific point of view.

[PR358-R] The MPEX Diagnostics System shall be designed to allow for ion temperature to be measured “at the source” and in the PMI chamber, both at the entrance to the chamber and near the target.

(in phase 1) The line-averaged ion temperature shall be measured with the temporal resolution larger than 10 Hz, and the measurable range of 1 – 50 eV.

(in phase 2) The ion-temperature profile shall be measured with more than 5 spatial points.

(in phase 2) The ion velocity shall be measured with the temporal resolution larger than 10 Hz.

2.3.3.1 Light Collection

Ion temperature measurement The light shall be observed from the perpendicular direction to the magnetic field line. In order to minimize the effect of the Zeeman splitting in the temperature measurement, the linear polarization component parallel to magnetic field line should be selected before the light enters the optical lens.

A linear polarizer shall be placed between the vacuum window and optical lens. Its polarization axis shall be parallel to the magnetic field. The vacuum window must not change the polarization of the transmitted light, although there is a risk caused by the thermal stress or birefringence of the window material. In the design phase, this risk must be minimized.

Lens must focus the light from plasma with the wavelength ranges from 400 – 1000 nm on an optical fiber edge. This lens may be the following product. In most measurements, the following product may be used;

https://www.oceaninsight.com/products/sampling-accessories/free-space-optics/collimating-lenses/74-acr The current design of the optical puck is shown in Figure 2.3-2, which has been demonstrated for the Proto-MPEX experiments. This can hold multiple collection lenses and can be attached to a single port. The following design updates are necessary for MPEX diagnostics:

• The puck must hold a linear polarizer in front of the lens.

• The puck should have an ability to cool the window, e.g., the inlet of the cooling air flow.

https://www.oceaninsight.com/products/sampling-accessories/free-space-optics/collimating-lenses/74-acr https://www.oceaninsight.com/products/sampling-accessories/free-space-optics/collimating-lenses/74-acr

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Figure 2.3-2. A cross section of the optical puck, which has been used for Proto-MPEX diagnostics. The cross section of the observation port is also shown.

Figure 2.3-3. Schematic illustration of the optical puck. The optical puck should be aligned so that the central one is the lens0, the lens 1 is closest to the source region, and in facing to the plasma the lens1 – lens4 is in the counter-clockwise direction.

For the ion-temperature profile measurement, another design with spatial resolution is required.

This measurement may share the collection optics with Thomson scattering. This sharing has several benefits: the alignment and calibration is standardized, the ability to measure both the ion and the electron profiles simultaneously, and minimizes the risk to add an additional window port on the device.

Ion flow measurement The light should be measured almost parallel to the magnetic field lines. The angle between the sight line and the magnetic field line shall be < 30 deg. A similar optical puck to the one shown in Figure 2.3-3 can be used for the ion-flow measurement, and no linear polarizer is necessary for this measurement.

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2.3.3.2 Measurement Locations

Light from two locations of the PMI-chamber (target and the upstream), and a single location for ECH-, ICH-, and Helicon regions should be captured. All the windows through which the light from MPEX is observed should retain the original polarization. However, there is a risk that the heat load to the window changes their polarization property. In order to minimize the risk, the window should be appropriately cooled and its thermal stress and thermal gradient should be minimized. To further mitigate the risks, several redundancy in the observation port shall be prepared, where at least two measurement locations may be prepared for each region. For example, one of the windows at the PMI chamber may be cooled more than that we expect enough, in order to make sure that the further cooling of the window does not change the result.

Also, in the later phase of the experiment (after the achievement of the KPP), the ion-temperature profile and the ion velocity shall be measured. The ports for these measurements should be allocated. The port callouts listed below are for reference only and are subject to change. The final port locations are identified on [2].

PMI chamber (in front of the sample holder)

- Port P.156-0 (the main system)

- Port P.156-2 (the backup system)

- Port P.151 shared with Thomson scattering (the profile measurement)

- Port P.104.h-0 (the flow measurement: the main system)

- Port P.104.h-1 (the flow measurement: the backup system) PMI chamber (upstream)

- Port P.112-0 (the main system)

- Port P.112-2 (the backup system) ECH region

- Port E.102 shared with Thomson scattering (the profile measurement)

- Port H.154-0 (the backup system)

- Port H.154-2 (the backup system) ICH region

- Port I.102-0 (the main system)

- Port I.102-2 (the backup system) Helicon region

- Port H.130-0 (the main system)

- Port H.130-4 (the main system)

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2.3.3.3 Light Transfer

The light transfer shall be made by multi-mode optical fibers. Three sets of the optical fiber bundles are required. The first fiber bundle should transfer the light from the MPEX to the fiber-terminal station near MPEX. (TBD). The second fiber bundle should transfer the light from the fiber-terminal station near MPEX to the fiber-terminal station in the diagnostic room.The third fiber bundle should transfer the light from the fiber-terminal station in the diagnostic room to the entrance slit of the spectrometer.

These fibers should transmit the light of 400 nm – 800 nm wavelength with an attenuation smaller than 100 dB/km. Their diameter may be optimized depending on the throughput and spatial resolution. Several types of optical fibers shall be prepared for the sake of flexibility. Typically, they may be larger than 400 um and smaller than 1 mm in diameter.

The pit – terminal optical fibers shall equip SMA1 connectors to both the ends. The fibers shall be placed in a cable tray or cable tube.

Most of the machine – pit optical fibers (which connects to the optical puck) shall equip SMA connectors. The optical fibers shall be shared for the port that are shared with Thomson scattering.

One end (the pit side) shall equip a SMA connector, while the other end should have a special design. See the details in the Thomson scattering section (Sec. 2.8).

The terminal – spectrometer optical fibers should have a SMA connector in one end (the terminal side). The spectrometer side should have a special alignment of the optical fibers. This design should be compatible with the spectrometer entrance.

2.3.3.4 Spectrometer

The spectrometer should have enough wavelength resolution as well as the ability to independently measure light introduced by multiple optical fibers. This may be the following product:

https://www.princetoninstruments.com/wp-content/uploads/2021/07/IsoPlane-Rev-C4-28-01- 2022.pdf The spectrometer shall equip a holder to keep the optical fiber (the terminal – spectrometer fiber) in front of the entrance slit of the spectrometer. This holder may be provided by the spectrometer manufacturer.

Two sets of spectrometers should be purchased; one is for the routine measurement and the other one is for back up and user-requested measurement.

The spectrometer may be placed on an optical table to avoid mechanical vibration as much as possible.

1 SMA is a type of fiber optic connector conforming to IEC 61754-22 https://www/

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2.3.4 Camera

The scientific camera shall be used to convert the photon intensity into digital signal. This camera should have enough sensitivity, resolution, and temporal response. This may be the following product:

https://www.princetoninstruments.com/wp-content/uploads/2020/10/ProEM- HS_512BX3_datasheet.pdf This camera should be connected to the spectrometer. The connecting flange to mount to the spectrometer may be provided by the manufacturer.

Two set of cameras should be purchased.

This camera should be connected to the timing system. The camera should obtain the trigger signal from the system to start the data acquisition at the exact timing, while this camera should output the signal that indicates the exposure times (the fire signal), which should be monitored by the timing system.

2.3.4.1 Calibration Lamp

The calibration lamp should provide the impurity emission line, with so low ion temperature that the line can be used to estimate the instrumental function of the spectrometer and the rest wavelength.

The lamp should emit enough amount of photon of the targeted wavelength to measure the profile with the reasonable exposure time (~5 s).

The light from the calibration lamp should be introduced by the optical fiber (the terminal – spectrometer fiber). The other end should be connected to a collection lens and direct to the calibration lamp.

The lamp should be operated by a high-voltage power supply. This power supply should be controlled by the following personal computer.

2.3.4.2 Input Output Controller

An Input Output Controller (IOC) should control the spectrometer, the camera, and the calibration lamp. This IOC should have enough computation power to control these instruments and make an analysis. One IOC should be prepared for each spectrometer (2 IOCs in total).

2.3.5 Software Requirements

2.3.5.1 Software on the IOC

The following control functions should be implemented in the software.

Before the experiment Pulse number, planned pulse length, and required temporal resolution should be accessed from this computer through network.

During the experiment https://www.princetoninstruments.com/wp-content/uploads/2020/10/ProEM-HS_512BX3_datasheet.pdf https://www.princetoninstruments.com/wp-content/uploads/2020/10/ProEM-HS_512BX3_datasheet.pdf

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The exposure time or gain shall be changed during the experiment, depending on the brightness of the plasma (in every ~101 s frequency). Since the vendor-provided software (LightField) does not support this feature and is not compatible with steady-state operation, a customized EPICS driver shall be developed to realize this function.

From the obtained spectrum, the ion temperature and its uncertainty must be evaluated.

The temperature and its uncertainty shall be sent to the data server.

The evaluation shall be done during the exposure for every < 101 s.

After the experiment Turn on the calibration source and measure its emission spectrum by the system. Calibrate the wavelength and instrumental function for the next experiment.

2.3.5.2 Timing Signal

Timing signal should be provided to indicate the start timing of the experiment. This may be a 5V pulse with the impedance smaller than 50Ω, but some cameras have ability to control the impedance. The rising edge shall indicate the experimental start time. The rise time should be smaller than 10 us.

2.3.5.3 Data Transfer

Raw data and analyzed data should be sent over the ethernet cable from the IOC to EPICS.

2.3.5.4 Calibration Lamp

The calibration lamp should be turned on just after each experiment, and turned off after the calibration data is taken.

2.3.6 Environmental Requirements

The temperature of the diagnostic room must be in 0 to 30°C ambient. Their temporal variation should be smaller than 1°C. The relative humidity must be between 0 to 70%, and non-condensing.

The optical table on which the high-resolution spectrometers system sit may have the size of ~1 x 2 m2 table size. ~60 cm open space should be retained around the optical table.

120 V power supply is required for the spectrometer (10 W), camera (80 W), PC (600 W), and calibration lamp (100 W at peak).

The air flow may be provided to cool the observation window.

2.4 SYSTEM BASIC CONFIGURATION: VISIBLE CAMERA

Visible cameras provide visible images of the plasma and in-vessel components of MPEX.

During the plasma operation, the visible cameras should capture the emission from plasmas, and give an insight to the current operation status. This does not only provide quantitative emission intensities from plasmas, but also give us an insight for the plasma operation. Unexpected

MPEX-07-SRD-001-R2 Page 30 of 102 accidents, such as the flake generation and arching, are expected to be first captured by the visible camera. Also, the cameras shall be used to inspect in-vessel components. Any damage might be first captured by the cameras. Therefore, these cameras are used both for plasma measurement and machine control.

During the experiment, the visible cameras should keep capturing the visible images. These visible images may be used for the machine control and machine monitoring. Therefore, the captured images should be live streamed in the control room. On the other hand, if any unexpected accident happens, the visible movies shall be used for the inspection purpose with the maximum resolution and frame rate. For example, the arching time scale is ~ 1 ms.

Satisfying these two use cases is a challenge.

After the experiment, the visible cameras are used to inspect the in-vessel components. As there is no light source in the chamber except for the plasma itself, some form of illumination is necessary.

The field of view should be as wide as possible, and at least one camera should be attached to each chamber, i.e., the PMI-, ECH-, Helicon-, ICH- and dump chambers.

The visible camera

• should cover the all the chambers.

• should provide fast movie with 1 kHz, at least for some location / duration.

• should provide real-time image, at least for some location.

• can equip a narrow-band filter to choose light emission.

• can provide illumination to inspect any damage in the chamber.

2.4.1 Design Overview

Figure 2.4-1 shows schematically how the visible cameras are connected to the MPEX device.

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Figure 2.4-1. Overview of the visible camera systems.

An overview of the visible camera systems is shown in Figure 2.4-1. Two types of visible cameras are shown. One has a better capability of the fast framing (identified as fast cameras), while the other is more suitable for the real-time capture (real-time cameras).

Each camera equipment requires an imaging lens. The light from the plasma and in-vessel illumination will go through an observation port and is imaged on the image sensor by the imaging lens.

(Figure 2.4-1 top right) The real-time cameras will receive a triggering signal from the main control system and start capturing and video streaming to a dedicated server and store the visible movie for the entire experiment.

(Figure 2.4-1 top left) Fast cameras may have a limitation of the length of the fast movie. Only a subsection or part of the captured images is saved. The capture may be started by a trigger from an event-detection system, and after the capture, the captured movie will be sent to EPICS. It is also expected that the fast-cameras can stream low-resolution low-frame-rate movies. An option to save these low frame rate movies should be permitted by EPICS.

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(Figure 2.4-1 bottom) The illumination lamps for the in-vessel inspection should be placed in the diagnostic hole. The light from the lamp will be transferred by optical fibers to MPEX and injected into the chamber through observation windows.

2.4.2 Requirements

There are explicit requirements from scientific point of view.

[701.044-R] The MPEX Diagnostics System shall be designed to allow for narrow-band filter measurements of light emission (e.g., Deuterium Balmer-alpha light) to be measured with a periodicity of 1 m along the MPEX device length from dump plate to target plate (e.g., using Filterscopes and/or fast camera imaging) for purposes of Plasma dynamics.

[PR359-R]

[701.060-R] The MPEX Diagnostic System cameras shall be designed to be used to inspect in-vessel components post-discharge, with illumination provided through dedicated ports.

[PR434-R]

[PR431-R] An in-vessel viewing capability shall be provided that allows viewing and inspection of plasma-facing components in MPEX (i.e., dump, limiter, target) and the front end of heating systems (helicon window, ECH launcher, ICH window).

[PR432-R] The in-vessel viewing capability shall be designed to operate with the vacuum vessel under vacuum.

[PR-434-R] These cameras shall be used to inspect in-vessel components post-discharge, with illumination provided through dedicated ports.

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Figure 2.4-2. Diagnostic layout for deployment of the visible camera system

2.4.3 Instrument Requirements

Visible camera systems will be installed to all the chambers, PMI, ICH, ECH, Helicon, Dump regions. Currently considered diagnostic layout is shown in Figure 2.4-2. Each camera should equip imaging lens. Some cameras may equip a periscope to keep better field of view.

MPEX-07-SRD-001-R2 Page 34 of 102

2.4.3.1 Windows

The heat flux to the observation window should be smaller than the limit of the glass material. If it is necessary, the perforated gasket should be inserted in front of the window. Its hole spacing should be smaller than 2 mm, and the hole diameter should be maximized. The temperature of the camera should be kept less than 70℃.

2.4.3.2 Imaging Lens

To inspect as wide of a region as possible, the optical layout should be optimized. All the cameras should equip an imaging lens. To keep better field of view, some cameras (one for PMI region, and two cameras in ICH region.) shall equip an appropriate periscope. Although it is not yet designed, having one periscope for the Helicon region is also preferable.

The requirements for each imaging lens are as follows:

PMI region (fast camera 1) / ICH region (fast camera 2) The distance from the camera to the main object (material sample) is ~70 cm. This should be imaged through a periscope, the mirror is ~15 cm away from the front lens and the size of the mirror (pupil) is ~ 3 cm. The possible field of view is ~15 cm.

The focal length of the lens shall be ~50 mm, to image this field of sight to the image sensor (~10 mm). The minimum focus distance is shorter than 70 cm. #F of the lens should be smaller than 3. The lens should equip an F-mount flange.

The recommended product is Nikon, Nikkor 50mm f/1.4D (https://www.nikonusa.com/en/nikon-products/product/camera-lenses/af-nikkor-50mm-f%252f1.4d.html), which has 50 mm focal length with #F=1.4, and minimum focus distance of 45 cm.

PMI region (real-time camera 1) The focal length of the lens should be ~10 mm, in order to image this field of sight (~50 cm wide at 100 cm from the port) to the sensor (~5 mm). The minimum focus distance of the lens should be shorter than 70 cm. #F of the lens should be smaller than 1.5 to keep maximum amount of the photons. The lens should equip a C-mount flange.

The recommended product is Thorlabs MVL12M23 (https://www.thorlabs.com/thorproduct.cfm?partnumber=MVL12M23), which has 12 mm focal length with #F=1.4, and minimum focus distance of 15 cm.

ICH region (real-time camera 2) The distance from the camera to the main object (material sample) is ~70 cm. This should be imaged through a periscope, the mirror is ~15 cm away from the front lens and the size of the mirror (pupil) is ~ 3 cm. The possible field of view is ~15 cm.

https://www.nikonusa.com/en/nikon-products/product/camera-lenses/af-nikkor-50mm-f%252f1.4d.html https://www.nikonusa.com/en/nikon-products/product/camera-lenses/af-nikkor-50mm-f%252f1.4d.html https://www.thorlabs.com/thorproduct.cfm?partnumber=MVL12M23

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The focal length of the lens should be ~25 mm, to image this field of sight to the image sensor (~5 mm). The minimum focus distance is shorter than 70 cm. #F of the lens should be smaller than 2. The lens should equip a C-mount flange.

The recommended product is Thorlabs, MVL25M23 (https://www.thorlabs.com/thorproduct.cfm?partnumber=MVL25M23), which has 25 mm focal length with #F=1.4, and minimum focus distance of 20 cm.

ECH region (fast camera 3) / Helicon region (fast camera 4) The distance from the camera to the main object (material sample) is ~40 cm. The possible field of view is ~20 cm. The focal length of the lens should be ~20 mm, to image this field of sight to the image sensor (~10 mm). Minimum focus distance should be larger than 30 cm. #F of the lens should be smaller than 2. The lens should equip an F-mount flange.

The recommended product is Nikon AF-S NIKKOR 20mm f/1.8G ED (https://www.nikonusa.com/en/nikon-products/product/camera-lenses/af-s-nikkor-20mm-f%252f1.8g-ed.html), which has 20 mm focal length with #F=1.8, minimum focus distance of 20 cm.

Dump region (fast camera 5) The distance from the camera to the main object (material sample) is ~80 cm. The possible field of view is ~40 cm. The focal length of the lens should be ~20 mm, to image this field of sight to the image sensor (~10 mm). Minimum focus distance should be larger than 80 cm. #F of the lens should be smaller than 2. The lens should equip an F-mount flange.

The recommended product is Nikon, AF-S NIKKOR 20mm f/1.8G ED (https://www.nikonusa.com/en/nikon-products/product/camera-lenses/af-s-nikkor-20mm-f%252f1.8g-ed.html), which has 20 mm focal length with #F=1.8, minimum focus distance of 20 cm.

2.4.3.3 Periscopes

Some ports (PMI chamber, ICH region, and preferably Helicon region) may equip dedicated periscopes. The periscope should equip the first mirror with the diameter of larger than φ:3 cm.

The periscope tube should not intersect the field of view. The periscope mirror should tolerate with plasma irradiation.

2.4.3.4 Cameras

Two types of cameras (fast cameras / real-time cameras) share the imaging capability in different performances categories.

Fast cameras The fast cameras should be operated with more than 1,000 frames-per-second for a few seconds.

The camera should have a ‘pre-trigger’ capability, so that it can capture a buffer of frames before the arriving the trigger. The camera should operate at or below 1 T magnetic field.

https://www.thorlabs.com/thorproduct.cfm?partnumber=MVL25M23 https://www.nikonusa.com/en/nikon-products/product/camera-lenses/af-s-nikkor-20mm-f%252f1.8g-ed.html https://www.nikonusa.com/en/nikon-products/product/camera-lenses/af-s-nikkor-20mm-f%252f1.8g-ed.html…