Handbook of Vacuum Technology - GBV

Handbook of Vacuum Technology

Edited by Karljousten

Translated by C. Benjamin Nakhosteen

WILEY-BLACKWELL

WILEY-VCH Verlag GmbH & Co. KGaA

V

Contents

Preface XXV

ListofContributors XXVII

1 The History of Vacuum Science and Vacuum Technology 1 References 16 Further Reading 16

2 Applications and Scope of Vacuum Technology 17 References 24

3 Gas Laws and Kinetic Theory of Gases 25 3.1 Description ofthe Gas State 25 3.1.1 State Variables 25 3.1.2 Extensive Quantities 29 3.1.3 Equationof State of an Ideal Gas 31 3.1.4 Mixtures of Different Gas Species 33 3.2 Kinetic Theory of Gases 34 3.2.1 Model Conceptions 34 3.2.2 Wall Pressure due to Impacting Particles 35 3.2.3 Maxwell-Boltzmann Velocity Distribution 37 3.2.4 Collision Rate and Effusion 40 3.2.5 Size of Gas Particles and Free Path 41 3.3 Transport Properties of Gases 45 3.3.1 Pressure Dependence 45 3.3.2 Transport of Frictional Forces in Gases and Viscosity 47 3.3.3 Transport of Heat in Gases and Thermal Conductivity 51 3.3.4 Diffusion 58 3.4 Real Gases 60 3.4.1 Equations of State 60 3.4.2 Parricle Properties and Gas Behavior 65

Handbook of Vacuum Technology. Edited by Karl Jousten Copyright © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim ISBN: 978-3-527-40723-1

VI Contents

3.5 Vapors 71 3.5.1 Saturation Vapor Pressure 71 3.5.2 Evaporation Rate 74

References 77

4 Gas Flow 79 4.1 Typesof Flow, Definitions 79 4.1.1 Characterizing Flow, Knudsen Number, Reynolds Number 79 4.1.2 Gas Flow, Throughput, Pumping Speed 83 4.1.3 Flow Resistance, Flow Conductance 87 4.1.4 EfFective Pumping Speed ofa Vacuum Pump 88 4.2 Inviscid Viscous Flow, Gas Dynamics 90 4.2.1 Conservation Laws 90 4.2.2 Gradual Change of Cross-sectional Area: Isentropic

Changeof State 91 4.2.3 Critical Flow 94 4.2.4 Choked Flow at Low Outlet Pressure 96 4.2.5 Contraction of Flow into Aperture and Tube 98 4.2.6 Examples of Nozzle Flow 98 4.2.7 Straight and Oblique Compression Shocks 102 4.2.8 Laval Nozzle, Effluent Flow against Counterpressure 105 4.2.9 Flow around a Corner (Prandtl-Meyer Flow) 107 4.3 Frictional-Viscous Flow through a Tube 110 4.3.1 Laminar and Turbulent Flow through a Tube 110 4.3.2 Airflow through a Tube 114 4.3.3 Air Inflow to a Vessel, Examples 117 4.3.4 Tube at the Inlet ofa Pump, Examples 121 4.3.5 Flow through Ducts with Non-circular Cross Sections 124 4.3.6 Influence of Gas Species on Flow 126 4.4 Molecular Flow under High-vacuum and Ultrahigh-vacuum

Conditions 127 4.4.1 Flow Pattern, Definitions, Transmission Probability 127 4.4.2 Molecular Flow through an Aperture 131 4.4.3 Molecular Flow through a Tube with Constant Cross-sectional

Area 133 4.4.4 Molecular Flow through a Tube with Circular Cross Section 135 4.4.5 Molecular Flow through Tubes with Simple Cross-sectional

Geometry 136 4.4.6 Tube Bend and Tube Elbow 138 4 AI Series Connection of Tube and Aperture 141 4.4.8 Series Connection ofComponents 142 4.4.9 Molecular Flow through Conical Tube with Circular Cross Section

(Funnel) 145 4.4.10 Component in the Inlet Line ofa Pump 146

4.5 Flow throughout the Entire Pressure Range 147 4.5.1 Flow Ranges 147 4.5.2 Flow through a Thin Aperture with Circular Cross Section 147 4.5.3 Flow through a Long Tube with Circular Cross Section 150 4.6 Flow with Temperature Difference, Thermal Effusion,

Transpiration 154 4.7 Measuring Flow Conductances 158 4.7.1 Necessity of Measurement 158 4.7.2 Measurement of Intrinsic Conductances

(Inherent Conductances) 158 4.7.3 Calculation of Reduced Conductance

(Assembly Conductance) 160 4.7 .4 Measuring Reduced Conductances 160

References 162 Further Reading 262

5 Analytical and Numerical Caiculations of Rarefied Gas Flows 163 5.1 MainConcepts 163 5.1.1 Knudsen Number and Gas Rarefaction 163 5.1.2 Macroscopic Quantities 164 5.1.3 Velocity Distribution Function 164 5.1.4 Global Equilibrium 165 5.1.5 Local Equilibrium 266 5.1.6 Boltzmann Equation 166 5.1.7 Transport Coefficients 168 5.1.8 Model Equations 170 5.1.9 Gas-surface Interaction 171 5.2 Methods of Caiculations of Gas Flows 174 5.2.1 General Remarks 174 5.2.2 Deterministic Methods 174 5.2.3 Probabilistic Methods 176 5.3 Velocity Slip and Temperature Jump Phenomena 178 5.3.1 Viscous Slip Coefficient 178 5.3.2 Thermal Slip Coefficient 180 5.3.3 Temperature Jump Coefficient 181 5.4 Momentum and Heat Transfer Through Rarefied Gases 182 5.4.1 Plane Couette Flow 182 5.4.2 Cylindrical Couette Flow 184 5.4.3 Heat Transfer Between Two Plates 187 5.4.4 Heat Transfer Between Two Coaxial Cylinders 190 5.5 Flows Through Long Pipes 193 5.5.1 Defmifions 194 5.5.2 Free-molecular Regime 295 5.5.3 Slip Flow Regime 296

VIII Contents

5.5.4 Transitional Regime 197 5.5.5 Arbitrary Pressure and Temperature Drops 202 5.5.6 Variable Cross Section 206 5.5.7 Thermo-molecular Pressure Ratio 208 5.6 Flow Through an Orifice 211 5.7 Modelingof Holweck Pump 213

References 218

6 Sorption and Diffusion 221 6.1 Sorption Phenomena and the Consequences, Definitions and

Terminology 221 6.2 Adsorption and Desorption Kinetics 226 6.2.1 Adsorption Rate 226 6.2.2 Desorption Rate 227 6.2.3 Hobson Model of a Pump-down Curve 228 6.2.4 Monolayer Adsorption Isotherms 232 6.2.5 Multilayer Adsorption and Brunauer-Emmett-Teller (BET)

Isotherm 234 6.2.6 Monolayer Time 236 6.3 Absorption, Diffusion, and Outgassing 237 6.4 Permeation 243


7 Positive Displacement Pumps 247 7.1 Introduction and Overview 247 7.2 Oscillating Positive Displacement Pumps 250 7.2.1 Piston Pumps 250 7.2.2 Diaphragm Pumps 252 7.2.2.1 Design and Principleof Operation 252 7.2.2.2 Pumping Speed and Ultimate Pressure 253 7.2.2.3 Gas Ballast 255 7.2.2.4 Drive Concepts 256 7.2.2.5 Ultimate Pressure 256 7.2.2.6 Influence of Gas Species on Pumping Speed and Ultimate

Pressure 257 7.2.2.7 Influence of Rotational Speed on Ultimate Pressure 257 7.2.2.8 Design Principles 259 7.2.2.9 Diaphragm Pumps in Chemical Laboratories 260 7.2.2.10 Diaphragm Pumps as Backing Pumps to Turbomolecular

Pumps 260 7.2.2.11 Diaphragm Pumps Combined with other Types of Vacuum

Pumps 264

7.3 Single-shaft Rotating Positive Displacement Pumps 265 7.3.1 Liquid Ring Vacuum Pumps 265 7.3.1.1 Design and Principleof Operation 265 7.3.1.2 Operating Properties and Dimensioning 267 7.3.1.3 Designs 270 7.3.1.4 Pump Units with Liquid Ring Vacuum Pumps 272 7.3.1.5 Suggestions for Economical Operation 275 7.3.2 Sliding Vane Rotary Pumps 277 7.3.2.1 Operating Principle and Design 277 7.3.2.2 Dry Running Sliding Vane Rotary Pumps 278 7.3.2.3 Oil-lubricated Sliding Vane Rotary Pumps 279 7.3.2.4 Once-through Lubricated Sliding Vane Rotary Pumps 281 7.3.2.5 Operating Behavior and Recommendations 282 7.3.2.6 Characteristic Curves and Ratings 284 7.3.3 Rotary Plunger Pumps 286 7.3.3.1 Principle of Operation and Technical Design 286 7.3.3.2 A Comparison of Sliding Vane Rotary Pumps and Rotary Plun

Pumps 289 7.3.4 Trochoidal Pumps 290 7.3.5 Scroll Pumps 291 7.3.5.1 Principle of Compression 292 7.3.5.2 Design 293 7.3.5.3 Applications and Advantages 294 7.4 Twin-spool Rotating Positive Displacement Pumps 295 7.4.1 Screw Type Pumps 295 7.4.1.1 Operating Principle and Technical Design 295 7.4.1.2 Heat Behavior and Technical Notes 301 7.4.2 Claw Pumps 303 7.4.2.1 Compression Principle 304 7.4.2.2 Comparison with Roots Pumps 307 7.4.2.3 Multistage Claw Pumps and Pump Combinations 307 7.4.2.4 Speed Control 309 7.4.2.5 Fields of Application 309 7A3 Roots Pumps 309 7.4.3.1 Principleof Operation 310 7.4.3.2 Technical Setup 311 7.4.3.3 Theoretical Basics 313 7.4.3.4 Effective Gas Flow 313 7.4.3.5 Compression Ratio KQ at Zero Delivery 313 7.4.3.6 Effective Compression Ratio and Volumetrie Efficiency 315 7.4.3.7 Gradation of Pumping Speed between Fore Pump and Roots

Pump 316 7.4.3.8 Pumping Speed and Ultimate Pressure 319 7.4.3.9 Installation and Operating Suggestions 322

X Contents

7.5 Specific Properties of Oil-sealed Positive Displacement Pumps 323

7.5.1 Pumping Speed and Producible Ultimate Pressure 323 7.5.1.1 Pumping Speed and Ultimate Partial Pressure 323 7.5.1.2 Ultimate Pressure and Oil Selection 325 7.5.2 Oil Backflow 328 7.6 Basics of Positive Displacement Pumps 329 7.6.1 Pumping Down Vapors - Gas Ballast 329 7.6.2 Power Requirements 333 7.6.2.1 Isothermal Compression 334 7.6.2.2 Adiabatic Compression 334 7.6.2.3 Polytropic Compression 335 7.6.2.4 Compression Power 335 7.7 Operating and Safety Recommendations 337 7.7.1 Installation 337 7.7.2 Starting and Shut Down, Inlet Valves 338 7.7.3 Pump Selection and Operating Recommendations 339 1.1' A Technical Safety Recommendations 340 7.8 Specific Accessories for Positive Displacement Pumps 342 7.8.1 Sorption Traps 342 7.8.2 Safety Valves 343 7.8.3 Oil Filter and Oil Cleaning 343 7.8.4 Exhaust Filter (Oil-mist Separator) 345 7.8.5 Dust Filters 346

References 348 Further Reading on Positive Displacement Pumps 351

8 Condensers 353 8.1 Condensation Processes under Vacuum 353 8.1.1 Fundamentals 353 8.1.2 Condensation of Pure Vapors 355 8.1.3 Condensation of Gas-Vapor Mixtures 359 8.1.4 Coolants 362 8.2 Condenser Designs 362 8.2.1 Surface Condensers for Liquid Condensation 362 8.2.2 Direct Contact Condensers 364 8.2.3 Condensate Discharge 366 8.2.4 Surface Condensers for Solid Condensation 368 8.3 Integrating Condensers into Vacuum Systems 368 8.3.1 Condensers Combined with Vacuum Pumps 368 8.3.2 Control 372 8.4 Calculation Examples 372

References 374

Contents XI

9 Jet and Diffusion Pumps 375 9.1 Introduction, Overview 375 9.2 Liquid Jet Vacuum Pumps 377 9.3 Steam Jet Vacuum Pumps 379 9.3.1 Design and Function 379 9.3.2 Performance Data, Operating Behavior, and Control 381 9.3.3 Multistage Steam Jet Vacuum Pumps 384 9.3.4 Organic Vapors as Driving Pump Fluids 387 9.4 Diffusion Pumps 388 9.4.1 Design and Principleof Operation 388 9.4.2 Pump Fluids 393 9.4.3 Baffles and Vapor Traps 394 9.4.4 Fractionating and Degassing 395 9.4.5 Operating Suggestions 397 9.4.6 Pumping Speed, Critical Backing Pressure, Hybrid Pumps 397 9.4.7 Calculating Performance Characteristics of Diffusion and

Vapor Jet Pumps by Using a Simple Pump Model 400 9.5 Diffusion Pumps versus Vapor Jet Pumps 408

References 410 Further Reading on Positive Displacement Pumps 411

10 Molecular and Turbomolecular Pumps 413 10.1 Introduction 413 10.2 Molecular Pumps 415 10.2.1 Gaede Pump Stage 416 10.2.2 Holweck Pump Stage 419 10.2.3 Siegbahn Pump Stage 420 10.3 Physical Fundamentals of Turbomolecular Pump Stages 421 10.3.1 Pumping Mechanism 421 10.3.2 Pumping Speed and Compression Ratio 422 10.3.3 Gaede and Statistical Theory of the Pumping Effect 423 10.3.4 Thermal Balance 426 10.4 Turbomolecular Pumps 430 10.4.1 Design 430 10.4.2 Operating Principle 430 10.4.3 Rotor Materials and Mechanical Requirements 431 10.4.4 Hearing and Cooling 433 10.4.5 Special Designs 433 10.4.6 Safety Requirements 435 10.4.7 Bearing Arrangements for Rotors in Turbomolecular

Pumps 436 10.4.7.1 Shaft with Two Ball Bearings 436 10.4.7.2 Shaft with Permanent Magnet Bearing and Ball Bearing 437

XII Contents

10.4.7.3 Magnetic Bearings 437 10.4.8 Drives and Handling 439 10.4.9 Performance Characteristics 440 10.4.9.1 Pumping Speed 440 10.4.9.2 Compression Ratio, Ultimate Pressure, Base Pressure 441 10.4.9.3 Pump-down Times for Vacuum Chambers 442 10.4.9.4 Pumping of High Gas Throughputs 444 10.4.10 Operation and Maintenance 445 10.4.10.1 Backing Pump Selection 445 10.4.10.2 General Notes 446 10.4.10.3 Start-up 446 10.4.10.4 Obtaining Base Pressure 446 10.4.10.5 Operation in Magnetic Fields 446 10.4.10.6 Venting 446 10.4.10.7 Maintenance 447 10.4.11 Applications 448

References 450

11 Sorption Pumps 453 11.1 Introduction 453 11.2 Adsorption Pumps 455 11.2.1 Working Principle 455 11.2.2 Design 457 11.2.3 Ultimate Vacuum and Pumping Speed 458 11.2.3.1 Ultimate Pressure with a Single Adsorption Pump 458 11.2.3.2 Ultimate Pressure with two or more Adsorption Pumps 459 11.2.4 Improving Ultimate Vacuum by Pre-evacuation or Filling with

Foreign Gas 461 11.2.5 Operating Suggestions 461 11.3 Getter 463 11.3.1 Mode of Operation and Getter Types 463 11.3.2 NEG Pumps 464 11.3.2.1 Fundamentals of BulkGetters/NEG 464 11.3.2.2 Design of NEG Pumps 468 11.3.2.3 Pumping Speed and Getter Capacity 469 11.3.2.4 Applications of NEG Pumps 471 11.3.2.5 Safety and Operating Recommendations 472 11.3.3 Evaporation/sublimation Pumps 473 11.3.3.1 Evaporation Materials 473 11.3.3.2 Pumping Speed 474 11.3.3.3 Getter Capacity 477 11.3.3.4 Design of Evaporation Getiers 478 11.4 Ion Getter Pumps 482 11.4.1 Working Principle 482

Contents XIII

11.4.2 Technical Design (Diode Type) 487 11.4.3 Pumping Speed 487 11.4.4 The Differential Ion Pump 490 11.4.5 Triode Pumps 491 11.4.6 Distributed Ion Pumps 494 IIA.7 Residual Gas Spectrum 494 11.4.8 Operation 495 11.5 Orbitron Pumps 496


12 Cryotechnology and Cryopumps 501

12.1 Introduction 501 12.2 Methodsof Refrigeration 502 12.2.1 Concepts and Fundamental Laws of Thermodynamics 502 12.2.2 Special Cooling Processes 505 12.2.2.1 Joule-Thomson Expansion, Linde Process 505 12.2.2.2 Expansion Engines 507 12.2.2.3 Claude Process 508 12.2.2.4 Stirling Process 509 12.2.2.5 Gifford-McMahon Process 510 12.2.2.6 General CharacteristicsofRefrigerating Systems 511 12.2.2.7 Low-temperature Measurement 513 12.3 Cryostat Technology 513 12.3.1 Cryostats 513 12.3.2 Vacuum-insulated Ducts 517 12.3.3 Refüling Equipment 518 12.3.4 Cooling Agent Loss 523 12.4 Cryopumps 527 12.4.1 Binding of Gases to Cold Surfaces 529 12.4.1.1 Gas Condensation 529 12.4.1.2 Cryotrapping and Cryosorption 529 12.4.2 Characteristics of Cryopumps 533 12.4.2.1 Starting Pressure pst 533 12.4.2.2 Ultimate Pressure jöuit 533 12.4.2.3 Pumping Speed 535 12.4.2.4 Service Life ts 536 12.4.2.5 Capacity (Maximum Gas Intake) 537 12.4.2.6 Heat Transfer to the Cold Surface 538 12.4.2.7 Thermal Conductivity of Condensate 539 12.4.2.8 Growth Rate of the Condensate Layer 540 12.4.2.9 Crossover Value 540 12.4.2.10 Maximum TolerablepV Flow 541

XIV Contents

12.4.3 Designs 541 12.4.3.1 Bath Cryopumps 542 12.4.3.2 Evaporator Cryopumps 543 12.4.3.3 Cryopumps with Refrigerating Machines

(Refrigerator Cryopumps) 544 12.4.3.4 Examples of Applications 548 12.4.3.5 Cryopumps in Nuclear Fusion Technology 548 12.4.3.6 Cryopumps in Aerospace Technology 548 12.4.3.7 Cryopumps in Particle Accelerators 550 12.4.3.8 Cryopumps in Industrial Systems 550 12.4.3.9 Cryopumps for UHV Systems 551 12.4.4 Development Trends for Cryopumps 552

References 553

13 Total Pressure Vacuum Gauges 555 13.1 Introduction 555 13.2 Mechanical Vacuum Gauges 556 13.2.1 Principle and Classification 556 13.2.2 Corrugated-diaphragm Vacuum Gauges 557 13.2.3 Capsule Element Vacuum Gauges (Measuring Range

lkPa-lOOkPa) 558 13.2.4 Bourdon Tube Vacuum Gauges (Measuring Range

lkPa-lOOkPa) 559 13.2.4.1 Quartz Bourdon Tube Vacuum Gauges 560 13.2.5 Diaphragm (Membrane) Vacuum Gauges 561 13.2.5.1 Diaphragm (Membrane) Vacuum Gauges with Mechanical

Displays (Measuring Range 0.1 kPa-100 kPa) 561 13.2.5.2 Diaphragm (Membrane) Vacuum Gauges with Electrical

Converters 563 13.2.5.3 Diaphragm (Membrane) Vacuum Gauges Using the Piezoresistive

Principle 564 13.2.5.4 Piezoelectric Vacuum Gauges 565 13.2.5.5 Resonant Diaphragm Vacuum Gauges 565 13.2.5.6 Capacitance Diaphragm Vacuum Gauges 566 13.2.5.7 Thermal Transpiration 569 13.2.6 Pressure Switches and Pressure Controllers 571 13.3 Spinning Rotor Gauges (Gas-friction Vacuum Gauges) 573 13.3.1 Measuring Setup and Measuring Principle 574 13.3.2 Retarding Effect due to Gas Fricrion 575 13.3.3 Measuring Procedure 579 13.3.4 Extending the Measuring Range towards Higher Pressures 580 13.3.5 Measuring Uncertainty 582 13.4 Direct Electric Pressure Measuring Transducers 583

13.5 Thermal Conductivity Vacuum Gauges 583 13.5.1 Principle 583 13.5.2 Thermal Conductivity Vacuum Gauges with Constant Wire Tem-

perature 587 13.5.3 Thermal Conductivity Vacuum Gauges with Constant

Heating 590 13.5.4 Thermocouple Vacuum Gauges 592 13.5.5 Thermistors 593 13.5.6 Guidelines for Operating Thermal Conductivity Vacuum

Gauges 593 13.6 Thermal Mass Flowmeters 594 13.7 lonization Gauges 596 13.7.1 Principle and Classification 596 13.7.2 Historyof lonization Gauges 597 13.7.3 Emitting-cathode lonization Gauges (Hot-cathode lonization

Gauges) 599 13.7.3.1 Measurement Principle 599 13.7.3.2 Design of Emitting-cathode lonization Gauges (Hot-cathode

lonization Gauges) 603 13.7.3.3 Concentric Triode 604 13.7.3.4 Fine-vacuum lonization Gauges 604 13.7.3.5 Bayard-Alpert lonization Gauges 605 13.7.3.6 Extractor lonization Gauges 610 13.7.3.7 Additional Types of Emitting-cathode lonization Gauges 613 13.7.3.8 Operating Suggestions for Emitting-cathode lonization

Gauges 614 13.7'.4 Crossed-field lonization Gauges 615 13.7.4.1 Penning Gauges 615 13.7.4.2 Magnetron and Inverted Magnetron 620 13.7.5 Comparison of Both Types of lonization Gauges 622 13.7.6 General Suggestions 623

References 627

14 Partial Pressure Vacuum Gauges and Leak Detectors 631 14.1 Introduction 632 14.2 Partial Pressure Analysis by Mass Spectrometry 631 14.2.1 Ion Source Design 637 14.2.1.1 Open Ion Sources (OIS) 638 14.2.1.2 Closed Ion Sources (CIS) 639 14.2.1.3 Molecular Beam Ion Sources (MBIS) 640 14.2.2 Filament Materials 641 14.2.3 Artifacts in the Mass Spectrum due to the Ion Source 642

XVI Contents

14.2.4 Mass Analyzers 643 14.2.4.1 Quadrupole Mass Analyzers 644 14.2.4.2 Miniaturized Quadrupole Mass Analyzers 648 14.2.4.3 Magnetic Sector Analyzers 649 14.2.5 Ion Detectors 653 14.2.5.1 FaradayCups 653 14.2.5.2 Secondary Electron Multiplier Detection 654 14.2.5.3 Discrete Dynode Electron Multipliers 655 14.2.5.4 Continuous Dynode Electron Multipliers (CDEM) 656 14.2.5.5 Microchannel Plate Detectors 657 14.2.6 Software for Mass Spectrometer Control 658 14.2.6.1 Analog Scan, Ion Current versus Mass 658 14.2.6.2 Selected Peaks, Ion Current versus Time 659 14.2.6.3 Leak Detection Mode 659 14.2.7 Further Applications of Mass Spectrometers 659 14.3 Partial Pressure Measurement using Optical Methods 659 14.4 Leak Detectors 662 14.4.1 Basic Principles and Historical Overview 662 14.4.2 Helium Leak Detectors 663 14.4.2.1 Requirements and General Functions of Vacuum

Leak Detection 663 14.4.2.2 Helium Sector Field Mass Spectrometers 664 14.4.2.3 Inlet Pressure of Helium LeakDetectors 665 14.4.2.4 Time Response of Helium Leak Detectors 666 14.4.2.5 Operating Principles of Helium Leak Detectors 667 14.4.2.6 Snifhng Devices for Helium Leak Detectors 671 14.4.2.7 Applications of Mass Spectrometer Helium Leak Detectors 672 14.4.3 Refrigerant Leak Detectors 672 14.4.3.1 Design and Operating Principle 672 14.4.3.2 Applications 675 14.4.4 Reference Leaks 675 14.4.4.1 Permeation Leaks 675 14.4.4.2 Conductance Leaks 676 14.4.4.3 Practical Realization of Reference Leaks 676 14.4.4.4 Calibrating Reference Leaks 677 14.4.5 Measuring Characteristics and Calibration of Leak Detectors 677 14.4.5.1 Leak Detectors as Test Equipment According to ISO 9001 677 14.4.5.2 Calibration Uncertainty 678 14.4.6 Leak Detectors Based on Other Sensor Principles 679 14.4.6.1 Helium Sniffers with Quartz Glass Membrane 679 14.4.6.2 Halogen Leak Detectors with Alkali Ion Sensors 679 14.4.6.3 Halogen Leak Detectors with Infrared Sensors 680

References 680

15 Calibrations and Standards 685 15.1 Introduction 685 15.2 Calibration of Vacuum Gauges 688 15.2.1 Primary Standards 688 15.2.1.1 Liquid Manometers 689 15.2.1.2 Compression Manometer after McLeod 692 15.2.1.3 Piston Gauges and Pressure Balances 695 15.2.1.4 Static Expansion Method 698 15.2.1.5 Continuous Expansion Method 703 15.2.1.6 Other Primary Standards 709 15.2.2 Calibration by Comparison 710 15.2.3 Capacitance Diaphragm Gauges 711 15.2.4 Spinning Rotor Gauges 716 15.2.5 Ionization Gauges 718 15.3 Calibrations of Residual Gas Analyzers 720 15.4 Calibration of Test Leaks 723 15.5 Standards for Determining Characteristics of Vacuum

Pumps 726 References 729

16 Materials 733 16.1 Requirements and Overviewof Materials 733 16.2 Materials for Vacuum Technology 734 16.2.1 Metals 734 16.2.1.1 The most Important Metals and Metal Alloys 735 16.2.2 Technical Glass 739 16.2.2.1 Basics 739 16.2.2.2 Properties of Important Glasses 741 16.2.3 Ceramic Materials 743 16.2.3.1 Basics 743 16.2.3.2 Properties of Important Ceramics 743 16.2.3.3 Ceramics in Vacuum Technology 744 16.2.3.4 Ceramic/Metal Joining Technologies 744 16.2.3.5 Zeolite 747 16.2.4 Plastics 747 16.2.4.1 Basics 747 16.2.4.2 Properties of Major Plastics 747 16.2.5 Vacuum Greases 749 16.2.6 Oils 750 16.2.7 Coolants 750 16.3 Gas Permeability and Gas Emissions of Materials 751 16.3.1 Fundamentals 751

Contents

16.3.2 Gas Permeability 751 16.3.2.1 Gas Permeability of Metals 751 16.3.2.2 Gas Permeability ofGlasses and Ceramics 753 16.3.2.3 Gas Permeability ofPlastics 754 16.3.3 Gas Emissions 756 16.3.3.1 Basics 756 16.3.3.2 Saturation Vapor Pressure (see also Section 3.5.1) 756 16.3.3.3 Surface Desorption, Gas Diffusion from Bulk Material,

Reference Values for Gas Emissions 758 16.3.3.4 Gas Diffusion from Bulk Material 758 16.3.3.5 Reference Values for Total Gas Emission Rates 762


17 Vacuum Components and Seals 765 17.1 Introduction 765 17.2 Permanent Connections 765 17.2.1 Weldedjoints 766 17.2.1.1 TIG (Tungsten Inert-gas) Welding 766 17.2.1.2 Micro-plasma Welding, Electron-beam Welding, Friction

Welding 767 17.2.2 Brazedjoints 767 17.2.3 Fused Joints 768 17.2.4 Joints with Metallizations 771 17.2.5 Cemented Joints 772 17.3 Detachable Joints 772 17.3.1 Seals and Sealing Faces 772 17.3.2 Required Forces 773 17.3.3 Ground-in Connections 774 17.3.4 Flange Connections 775 17.3.4.1 Swagelok® and Swagelok®-VCR® connectors 775 17.3.4.2 Klein Flange Components and Seals According to DIN 28403

(ISO 2861-1) 776 17.3.4.3 ISO-K Components and Seals According to DIN 28404

(ISO 1609) 777 17.IAA CF Components and Seals (ISO/TS 3669-2) 777 17.3.4.5 COF Components 778 17.3.4.6 Special Flanges and Special Seals 779 17.3.4.7 Vacuum Components and Vessels 779 17.3.4.8 Plug-type Connectors 780 17 .4 Vacuum Vessels 781 17.4.1 Design 781 17.4.1.1 Dimensioning of Vacuum Vessels and Calculation

Examples 782

17.4.2 Double-walled Vessels 784 17.5 Flexible Joints 785 17.6 Feedthroughs 787 17.6.1 Feedthroughs for Motion and Mechanical Energy 787 17.6.1.1 Feedthroughs for Linear Motion 787 17.6.1.2 Feedthroughs for Rotary Motion 788 17.6.1.3 Manipulators 788 17.6.2 Electrical Feedthroughs 789 17.6.2.1 Plastic Feedthroughs 789 17.6.2.2 Ceramic Feedthroughs 790 17.6.3 Feedthroughs for Liquids and Gases 792 17.6.3.1 Windows 793 17.6.4 Lubrication under Vacuum 793 17.7 Valves 795 17.7.1 Basics 795 17.7.1.1 Design, Dimensioning, and Requirements 796 17.7.1.2 Classification (Terms) 796 17.7.1.3 Actuation 796 17.7.1.4 Sealing of Valves and Materials 797 17.7.2 Corner Valves 797 17.7.3 Straight-way Valves 798 17.7.4 Sliding Valves 800 17.7.5 Gas Dosing Valves 801 17.8 Manufacturing and Surface Treatment of Vacuum

Components 802 17.8.1 Machining Techniques 802 17.8.2 Surface Treatment 803 17.8.3 Cleaning (Pre-cleaning and In-Situ) 805 17.8.3.1 Cleaning ofStainless Steel 806 17.8.3.2 Cleaning of Technical Glass 806 17.8.3.3 Cleaning ofCeramics 807 17.8.3.4 Vacuum Annealing 807 17.8.3.5 Baking 807 17.8.3.6 In-Situ Cleaning by Means of Glow Discharge and Chemically

Active Gas 808 References 809

18 Operating Vacuum Systems 811 18.1 Electronic Integration of Vacuum Systems 811 18.1.1 Control by Means of Process Sensors and Automated Data

Processing 811 18.1.1.1 Requirements and Applications 811 18.1.2 Integrated Solutions 812 18.1.2.1 Integration using Windows Winsock 814

XX Contents

18.1.2.2 ASCII Protocols 814 18.1.2.3 Standardized Bus Systems 815 18.1.2.4 Sensor Integration According to SECS and HSMS Standards 816 18.1.3 Process-data Analysis 818 18.2 General Guidelines for Ultimate and Working Pressures 820 18.2.1 Ultimate Pressure pu\t and Ultimate Working Pressure pw.ult of a

Vacuum Pump 820 18.2.2 Ultimate Pressure puit s of a Vacuum Apparatus or System 820 18.2.3 Working Pressure 821 18.2.4 Working Pressure Determined by Process Gas Flow 822 18.2.5 Working Pressure Determined by Evaporating Substances 823 18.2.6 Working Pressure Determined by Outgassing (compare Chapter 6

and Section 16.3) 826 18.2.7 Working Pressure Determined by Permeation Gas Flow (compare

Section 16.3.2) 826 18.2.8 Working Pressure Determined by Leakage Gas Flow 827 18.3 Techniques for Operating Low-vacuum Systems

(lOlkPa-lOOPa) 827 18.3.1 Overview 827 18.3.2 Assemblyof Low-vacuum Systems 829 18.3.3 Pumps: Types and Pumping Speeds 829 18.3.4 Low-vacuum Pump Stands 830 18.3.5 Low-vacuum Pressure Measurement 831 18.3.6 Pump-down Times in Low Vacuum 831 18.3.7 Venting 837 18.4 Techniques for Operating Fine-vacuum Systems

(100 Pa-0.1 Pa, lmbar-l(T3mbar) 839 18.4.1 Overview 839 18.4.2 Assemblyof Fine-vacuum Systems 839 18.4.3 Pumps: Types and Pumping Speeds 840 18.4.4 Pressure Measurement 840 18.4.5 Pump-down Time and Ultimate Pressure 841 18.4.6 Venting 845 18.4.7 Fine-vacuum Pump Stands 845 18.5 Techniques for Operating High-vacuum Systems

(10"1 Pa-10^5 Pa, 10"3 mbar-10"7 mbar) 847 18.5.1 Pumps: Types and Pumping Speeds 849 18.5.2 Treatment of Vacuum Gauges (Cleaning) 850 18.5.3 High-vacuum Pump Stands 851 18.5.3.1 High-vacuum Pump Stands with Diffusion Pumps (see also

Section 9.4.6) 851 18.5.3.2 High-vacuum Pump Stands with Turbomolecular Pumps 859 18.5.3.3 Fully Automatic High-vacuum Pump Stands 860 18.5.4 Pump-down Time and Venting 861

18.6 Techniques for Operating Ultrahigh-vacuum Systems (p < 1(T5 Pa, 10"7 mbar) 862

18.6.1 Overview 862 18.6.2 Design ofUHV Systems 863 18.6.3 Operating Guidelines for UHV Pumps 864 18.6.3.1 Adsorption Pumps 864 18.6.3.2 Ion Getter Pumps 865 18.6.3.3 Titanium Evaporation Pumps 866 18.6.3.4 Turbomolecular Pumps 867 18.6.3.5 Cryopumps 867 18.6.3.6 Bulk Getter (NEG) Pumps 867 18.6.4 Pressure Measurement 868 18.6.5 Pump-down Times, Ultimate Pressure, and Evacuating

Procedures 868 18.6.6 Venting 869 18.6.7 Ultrahigh-vacuum Systems 869 18.6.8 Ultrahigh-vacuum (UHV) Components 869 18.6.9 Ultrahigh-vacuum (UHV) Pump Stands 870 18.6.9.1 Large Ultrahigh-vacuum (UHV) Facilities 873

References 875

19 MethodsofLeakDetection 877 19.1 Overview 877 19.1.1 Vacuum Leak Detection 877 19.1.2 Overpressure Leak Detection 878 19.1.3 Search Gas Distribution in the Atmosphere in front of

a Leak 879 19.1.4 Measurement Results with the Sniffing Method 880 19.1.5 Search Gas Species 881 19.1.5.1 Helium 881 19.1.5.2 Noble Gases other than Helium 881 19.1.5.3 Hydrogen H2 882 19.1.5.4 Methane CH4 882 19.1.5.5 Carbon Dioxide C02 882 19.1.5.6 Sulfur Hexafluoride SF6 882 19.2 PropertiesofLeaks 883 19.2.1 Leak Rate, Units 883 19.2.2 TypesofLeaks 883 19.2.2.1 Properties of Pore-like Leaks 885 19.2.2.2 Permeation Leaks 887 19.2.2.3 Virtual Leaks in Vacuum Vessels 888 19.2.2.4 Liquid Leaks 888

Contents

19.3 Overview of Leak Detection Methods (see also DIN EN 1779) 889 19.3.1 General Guidelines for Tightness Testing 889 19.3.2 Methods without Search Gas (Pressure Testing) 890 19.3.2.1 Introduction 890 19.3.2.2 Pressure Loss Measurement 891 19.3.2.3 Pressure Rise Measurement 892 19.3.2.4 Additional Methods 893 19.3.3 Search Gas Methods without Helium 894 19.3.3.1 Basics 894 19.3.3.2 Vacuum Leak Detection with Non-helium Search Gas 894 19.3.3.3 Overpressure Leak Detection with Search Gases other than

Helium 896 19.4 Leak Detection using Helium Leak Detectors 896 19.4.1 Properties of Helium Leak Detectors 896 19.4.2 Testing of Components 897 19.4.2.1 Testing Procedure, Integral Testing 897 19.4.2.2 Procedure for Leak Localization 899 19.4.3 Testing of Vacuum Systems 901 19.4.3.1 General Considerations for Partial Flow Operation 901 19.4.3.2 Points on Systems for Connecting Leak Detectors 902 19.4.3.3 Detection Limit and Response Time 905 19.4.4 Overpressure (Sniffmg) Leak Detection with a Helium Leak

Detector 906 19.4.4.1 Integral Procedure (Total or Partial) 907 19.4.4.2 Leak Localization with a Sniffer 908 19.5 Leak Detection with Other Search Gases 908 19.5.1 Basics 908 19.5.2 Snifnng Leak Detection on Refrigerators and Air

Conditioners 908 19.6 Industrial Tightness Testing of Mass-production

Components 909 19.6.1 Basics 909 19.6.2 Industrial Testing ofSeries Components 909 19.6.2.1 Envelope Testing Method for Vacuum Components (Method AI in

EN 1779) 910 19.6.2.2 Vacuum Chamber Method for Overpressure Components (Method

B6inEN1779) 910 19.6.2.3 Testing of Hermetically Sealed Components by Means of Bombing

(Method B5 in EN 1779) 912 19.6.2.4 Testing of Food Packaging in flexible Test Chambers 913

References 914

Contents I XXIII

20 Appendix 915 20.A Tables 915 20.B Diagrams 950 20.C Common Abbreviations 965 20. D Quantities and Units 966 20.E Glossary, Symbols of Physical Quantities and their SI Units used in

this Book 968

Index 977

Directory of Products and Suppliers 997

Documents

Handbook of Vacuum Technology - GBV