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Preface Many scientific instruments for analyzing specimen surface such as the electron microscope and the Auger electron spectrometer require clean, ultrahigh vacuum. The electron microscope and Auger electron spectrometer need fine electron probe, requiring a field emission emitter which can well work under ultrahigh vacuum. In the electron microscope and the ion microscope, microdischarges due to applying high voltage to electrodes sometime occur, resulting in deterioration of image quality. ...
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N.Yoshimura Vacuum Technology Nanitechnology has reached a level where almost every new development and even every new product uses features of nanoscopic properties of materials. As a consequence, an enormous amount of scientific instruments is used in order to synthesize and analyze new structures and materials. Due to the surface sensitivity of such materials, many of these instruments require ultrahigh vacuum that has to be provided under extreme conditions like very high voltages. ... [weiter lesen] |
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| AUTOR | öffnen |
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Dr. Nagamitsu Yoshimura 3-22-75 Fujimoto Kokubunji, Tokyo 185-0031 Japan [weiter lesen] |
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Contents
1 Designing of Evacuation Systems 1
Selection of Pumping Speed 2
Pumping-down Characteristics 2
Steady-State Evacuation 3
Roughing System 3
Backstreaming of RP Oil Vapor 4
Backstreaming of DP Oil Vapor 6
Overload in High-Vacuum Evacuation Systems 8
DP In-Series System 14
Ultrahigh Vacuum Electron Microscopes 27
Know-how Technology in Designing UHV Evacuation Systems 31
References 32
2 Vacuum Pumps 35
Mechanical Pumps 35
Diffusion Pumps 38
Turbomolecular Pumps 41
Dry Vacuum Pumps 45
Cryopumps 51
Vapor Pressures for Gases 55
Sputter Ion Pumps 56
Noble Pumps for Inert Gases 60
Getter Pumps 68
Titanium-Sublimation Pumps 68
Non-Evaporable Getter (NEG) Pumps 69
Methods for Measuring Pumping Speeds 70
Orifice Method 70
Three-Gauge Method (Pipe Method)71
Three-Point Pressure Method (3 PP Method)72
References 76
3 Simulation of Pressures in High-Vacuum Systems 85
Conventional Calculation of System Pressures 85
3 A Vacuum Circuits 87
Basic Concept of Vacuum Circuits 87
Designing of Vacuum Circuits 89
Simulation of Pressures 91
Resistor-Network Simulation Method 91
Matrix Calculation of Pressures 94
3 B Molecular-Flow Conductance 108
Conductance 108
Transmission Probability 109
3 C Gas-Flow Patterns 117
References 119
4 Outgassing 123
Process of Outgassing 123
Diffusion 124
Recombination-limited Outgassing 134
Data of Outgassing 136
Stainless Steel 136
Electro-polishing and Vacuum Firing 137
Aluminum Alloy, Copper and Titanium 147
Permeation Through Elastomer Seals 148
Evaporation 156
Methods for Measuring Outgassing Rates 157
Differential Pressure-rise Method [4-41]159
Variable Conductance Method [4-43]161
Conductance Modulation Method [4-44]164
Two-Point Pressure Method and One-Point Pressure Method [4-45]167
References 168
5 Phenomena Induced by Electron Irradiation 175
5 A Electron/Photon Stimulated Desorption (ESD/PSD)176
5 B Polymerization of Hydrocarbon Molecules 182
Transport of Hydrocarbon Molecules in High Vacuum 182
Transport of Hydrocarbon Molecules in Ultrahigh Vacuum 185
Materials to be Polymerized by Electron Beam Irradiation 192
5 C Darkening in Secondary Electron Images in SEM 195
5 D Etching of Carbonaceous Specimens 198
References 199
6 Vacuum Gauges 205
Mechanical Gauges 207
Capacitance Manometer 207
Thermal Conductivity Gauges 209
Pirani Gauge 209
Viscosity Gauges 211
Spinning Rotor Gauge 211
Crystal Oscillation Gauge 214
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Index
AAbrading, 137
Absorbed gas layers, 130
Activation energies of desorption, 125
Activation energy for diffusion, 133
Ac-voltage breakdown characteristics, 281
Adlayer formation, 147
- Croxide, 147
- TiN, 147
Adsorbed surface layer, 185, 326
Adsorption foreline trap, 26
activated alumina balls, 26
- porous alumina balls, 5
Adsorption theory, 182
AES depth profiles, 141-142, 143, 145
AES spectrum, 141-143
Ageing process, 286
Air bake-out, 146
Air pressure, 266
Aluminum alloys, 147-148, 173, 178
anodized film, 148, 149
anodizing aluminum surfaces, 148
- particulate generation, 148
Alumite, 10, 11
Analogies, 102
Angular distribution of molecular flux, 118
Angular divergence of the electron beam, 327
Anode initiated microparticle, 265, 283
Anode-initiation model, 265, 282
Anodic oxidized film (layer) of aluminum, 123
Apparent source size, 304, 307
Arc initiation, 318
Argon instability, 61-62
Ar-pumping speed, 66-68
Atomic hydrogen concentration, 145
Avalanche discharge, 285
Avalanche electrons, 267-268
BBack diffusion, 14-15
Backscattered-electron images, 139
Backstreaming of DP oil vapor, 6, 7, 25
Backstreaming of RP oil vapor, 4, 5, 22
Backstreaming rate, 4, 5, 7, 8, 26
Bake-out, 127, 128, 146, 147
Basic concept, 87
"Basic" safety system, 23, 24, 25
Bayard-Alpert gauge (BAG), 150, 205, 221, 226, 228, 229, 230, 249, 321
Barkhausen-Kurtz oscillations, 224
- discharge between the filament and grid, 223
- electron bombardment outgassing, 222
- glass-tube-type, 221, 225
- Ohmic heating outgas, 222
BeCu-flanged RGA, 252
BEM micrograph, 140-141
Best fit equations, 118
Bias voltage, 287-290
Blunting and recession of the tips, 320
Boiler pressure, 40
Booster diffusion pump, 15, 16-17
Brightness, 301, 308, 317
Buffer tank, 12, 13, 21, 23
Build-up method, 10
Build-up treatment, 317
Built-up TF cathodes, 329
Buna-N, 153, 154
Butyl, 153, 154
By-pass valve, 4, 13
CCalibration, 72, 158
- relative calibration, 158
Capacitance manometer (gauge), 207-209, 257
Capillarity-induced surface diffusion, 320
Cascade DP system, 23-25
Cathode surface geometry, 326
Cathode voltage, 267-269
C content in steel, 143
Characteristic values, 87-88, 89, 90, 97, 100-102
- flow impedances, 88
- free outgassing rate, 87, 88, 89
- free sorption rate, 87, 88
- net outgassing rate, 86, 87, 88, 90, 94, 95
Chemical interactions, 221
Chemical polishing (CP), 123
Chemical reactions, 222
Chemical treatment, 137
Chromium oxide coatings, 274
Chromium plated mild steel, 137
Circuit analysis code, 107
Circumference of the sink, 191
Clump of material, 282
Coadsorption of zirconium and carbon monoxide, 330
Cold caps, 7
Cold trap, 7, 14, 15, 25
Compound molecular pump, 50
Compression ratios, 19, 38, 42, 44, 50
Computer program, 107
conductance of components, 107
conductance of each series component, 107
- gas-flow calculations, 107
- pressure of the pump, 107
- system pumpdown, 107
- transmission probability, 109-112
Concentration, 127, 131, 133, 134, 135, 145, 147, 176, 177
Concentration profiles, 134
Conditioning, 265
- Argon-glow conditioning, 265
- high-voltage conditioning, 265, 291, 293
- polymerization of adsorbed hydrocarbons, 295
Conductance modulation method, 158, 164
Cone angle, 320, 340
Conical field emission gun, 322, 323
- accelerating voltage, 322, 323, 334
- extraction voltage, 322-323, 331
- virtual source position, 322
Contamination build-up rate, 182, 184, 198
current density, 185, 186, 188, 198
- temperature, 183, 185, 187
Contamination cones, 187
Contamination layer, 195, 197
Contamination rings, 186
Conventional calculation of pressure, 85
Correlation in gas flow, 23
Corrosion resistance, 137
Cosine law distribution, 117, 270
Cr 2 O 3 layer, 137
Craters, 188
- deflecting force, 186
- electric dipole, 186
- electric field, 186
- positive charge, 186
Crossover pressure, 9, 53
Cross-section for formation of a cross-link, 187
Cryopump, 47, 51-56
cryopanels, 52, 54
- first-stage array, 55
- second-stage array, 55
- sorption panels, 51, 53
Crystal oscillator vacuum gauge, 207
- bending and stretching mode crystal oscillator, 214
- impedance of the quartz oscillator, 215
- pressure dependences of the impedance, 215
Cuprous oxide coating, 274
Current density, 186, 198, 271, 272, 302, 304
Current sources, 94, 95, 97, 102, 103
DDarkening in secondary electron images, 175, 195, 296
Dc glow discharge, 192
- air, 192
- Apiezon C, 192
- argon, 192
- fluorocarbon-oxide pump fluid, 192
- helium, 192
- hydrogen, 192
- oxygen, 192
- RT.F.E.-like deposit, 193
- perfluoropoly ether, 192, 193
- Santovac-5, 192
- Silicone 704, 192
DC-stability, 331
Dc-voltage breakdown characteristics, 281
Decontamination, 198
- carbon removal, 198, 199
- cooling-down process of the ACD fins, 198
- oxygen ions, 198
- oxygen partial pressure, 198
- vapor pressures of ice, 199
- water-vapor pressure, 198
Decrease in secondary-electron emission, 197
Desorption energies, 135
Desorption probability, 271-273
Diameter of the spacer, 266
Diaphragm capacitance gauge, 205
Differential evacuation system, 23
Differential pressure-rise method, 158, 159, 168
Diffusion, 124
Diffusion coefficient, 127, 131, 133, 145, 146, 187, 320
Diffusion limited analyses, 134
Diffusion limited outgassing, 135
Diffusion pump (DP), 38, 39
- back-side pipe, 40
Diffusion pump (DP) system, 1-2, 6, 7, 8, 9, 13, 14, 15-16, 25-27
- butterfly valves, 1, 12
Diffusion time constants, 126
Direct drive pump, 37
Discharge intensity, 57, 58-60, 70
Distribution pattern, 117
Dose in electrons per unit area, 187
Double-stage rotary pump, 42
DP 1-BT-RP system, 12, 13
DP 1-DP 2-BT-RP system, 12
DP in series system, 14-22
- cooling water, 16, 21, 24
- heater power, 18, 40
Dry vacuum pump (DVP), 35, 41, 45^7
EEffective gas source, 89-90
Effective pump, 50, 85, 89
Effective pumping speed, 2, 85, 106, 168
Effective resistance of the leak, 105
Efficiency of ionization, 227
Elapsed time after EBS treatment, 189, 190
Elastomer technology, 151
Electrical analogue, 103-105
- capacitances, 102
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