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Page
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| Preface |
xii
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| Biographical Note |
xiii
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| Acknowledgments
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xiv
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| 1
BASIC THEORY |
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1
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| 1.0 Introduction, Pump Classification
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1
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| 1.1 Pump Capacity |
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1
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| 1.2 Understanding Pump Behavior |
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1
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| 1.3
The Ideal Gas Assumptions |
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2
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| 1.4 Definitions of Temperature and Pressure |
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2
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| The
Ideal Gas Law or Equation of State |
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3
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| Manipulation
of the Equation of State |
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5
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| 1.5
Counting Molecules (or Atoms) |
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5
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| 1.6
Density, Pressure and Molecular Velocities |
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6
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| 1.7
Vapor Pressure |
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8
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| Surface
Pumping |
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11
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| Pumping
on a Liquid Cryogen |
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12
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| 1.8
Mean Free Path |
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12
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| 1.9
Thermal Conductivity of Gases |
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15
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| Gas
Flux Incident on a Surface |
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16
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| 1.10
Pumping Speed, a Convenient Abstraction |
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17
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| 1.11
Throughput |
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19
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| 1.12
Conductance, Another Convenient Abstraction |
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20
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| 1.12.1
Conductance Model Applications |
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22
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| Species
and Temperature Dependence |
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22
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| Pressure
Dependence of Conductance |
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22
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| System
Geometry Dependence for Molecular Flow |
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23
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| Molecular
Conductance for Different Gases |
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23
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| 1.13
Voltage, Current and Impedance Analogies |
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25
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| Constructing
Voltage Analogues of Complex Systems |
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28
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| 1.14
Dalton's Law of Linear Superposition |
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28
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| 1.15
Selective and variable Pumping Speed |
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32
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| 1.16
Measuring Pumping Speed |
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33
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| 1.16.1
Rate of Pumpdown |
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33
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| 1.16.2
Single Gauge Dome Method |
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36
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| 1.16.3
Three Gauge Method |
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37
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| 1.16.4
Fischer-Mommsen Dome |
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39
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| Three
Gauge Versus Fischer-Mommsen Results |
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41
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| Speed
Measurement Errors Due to Trace Gas Contamination |
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41
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| 1.17
System Diagnostics With Any Pump |
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42
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| Measuring
Throughput by Rate-of-Pressure-Rise |
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43
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| 1.18
Electrical Discharges in Gases |
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44
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| Ionizing
Gases |
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46
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| High
Pressure Electrical Discharges |
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46
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| Low
Pressure Ionization Processes |
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50
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| Ionization
Gauge Sensitivities |
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52
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| Partial
Pressure Gauges |
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53
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| Ion
Collectors |
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57
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| Spectra
Interpretation |
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57
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| Gauge
Calibration Methods |
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59
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| 1.19
Vacuum Seals |
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62
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| 1.19.1
Elastomer Seals |
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62
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| Outgassing
From Elastomers |
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63
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| 1.19.2
Metal Seals |
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65
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| 1.20
Comments on Helium Leak Detection |
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71
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| 1.20.1
System Applications |
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71
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| 1.20.2
Leak Checking Systems Appended by Capture Pumps |
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76
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| Problem
Set |
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77
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| References
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79
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| 2
SPUTTERING-ION PUMPING |
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83
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| 2.0
Introduction |
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83
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| 2.1
The Penning Cell |
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84
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| 2.2
I+/ P Characteristics in Penning Cells |
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86
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| Qualitative
I/P Characteristics |
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90
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| 2.3
Pumping Speed Abstraction |
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93
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| 2.4
The Making of Sputter-Ion Pumps |
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94
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| 2.4.1
Pumping Mechanisms and Materials |
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94
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| Sputtering
Yield |
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94
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| Physisorption
and Binding Energies |
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97
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| Chemisorption |
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99
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| 2.4.2
Diode Pumps |
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102
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| The
Need for Clean Pumping |
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102
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| 2.4.3
Noble Gas Instabilities |
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105
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| SLAC
Pump Instability Problem |
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106
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| Diodes
With Slotted Cathodes |
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108
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| The
Galaxy Pump |
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|
109
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| 2.4.4
The Triode Pump |
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110
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| Magnetic
Fields in Diodes and Triode Pumps |
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113
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| Field
Emission in Triode Pumps |
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114
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| 2.4.5
The Differential Sputtering Pump |
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114
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| The
High Energy Neutral Theory |
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|
115
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| Beware
of Shortcuts |
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118
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| 2.5
Hydrogen Pumping |
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119
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| 2.5.1
Hydrogen Pumping in Diode Pumps |
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121
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| Diffusion
in the Cathodes |
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127
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| Titanium
Cathode Material, a Model |
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130
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| Ti-6Al-4V
Cathode Material |
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133
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| Beta-Stabilized
Cathode Materials |
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133
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| Diodes
With Aluminum Cathodes |
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134
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| Hydrogen
Burial in Pump Walls |
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136
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| Conclusion
on Hydrogen Pumping |
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137
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| 2.6
Triode Pumping |
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138
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| 2.7
Transient Speed Effects |
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142
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| 2.8
Pumping Gas Mixtures |
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143
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| 2.9
High Pressure Operation |
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145
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| Advantages
of Low Pressure Operation |
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149
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| 2.10
Sputter-Ion Pumping Helium |
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|
149
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| Regeneration
After Pumping Helium |
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153
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| 2.11
Pumping Elements Located in Antechambers or Pockets |
|
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154
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| Distributed
Sputter-Ion Pumps (DIPs) |
|
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156
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| 2.12
Pump Power Supplies |
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158
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| 2.13
Magnet Designs |
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160
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| 2.14
More on the Nature of Penning Discharges |
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164
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| 2.14.1
Space Charge Distribution in Penning Cells |
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164
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| 2.14.2
More on Sputtering Patterns on Pump Cathodes |
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170
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| Noise
in Sputter-Ion Pumps |
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171
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| 2.14.3
Striking Characteristics |
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172
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| 2.14.4
Use of Very High Magnetic Fields |
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173
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| 2.15
Other Considerations |
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173
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| Maintenance
and Trouble Shooting |
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173
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| 2.16
A Summary of Advantages and Disadvantages |
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|
175
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| Appendix
2A - Electrostatic Getter-Ion Pumps |
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|
177
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| Problem
Set |
|
|
179
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| References
|
|
|
181
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|
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| 3
TITANIUM SUBLIMATION PUMPING |
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|
195
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| 3.0
Introduction |
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|
195
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| 3.1
Sticking Coefficients |
|
|
196
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| 3.2
Pump Speed vs. Sticking Coefficient, a
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|
|
200
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| Titanium
and Conductance Limited Operation |
|
|
203
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| Dependency
of a on gas, Film Thickness and
Temperature |
|
|
204
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| 3.3
Synthesis, Displacement and Dissociation of Gases |
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|
208
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| 3.4
Sublimation Sources |
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|
210
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| Filamentary
Sources |
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211
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| Constant
Current Operation |
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212
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| Constant
Voltage Operation |
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214
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| Radiantly
Heated Sources |
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216
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| E-Gun
Sources |
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218
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| 3.5
Combination Pumping |
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220
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| Pealing
of Titanium Films |
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222
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| 3.6
Advantages and Disadvantages of TPS Pumping |
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222
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| Problem
Set |
|
|
223
|
| References |
|
|
224
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|
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| 4
NONEVAPORABLE GETTERS (NEG) |
|
|
229
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| 4.0
Introduction |
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|
229
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| 4.1
Mechanical Features |
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|
229
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| 4.2
NEG Pumping Mechanisms |
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232
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| The
Pumping of CO, CO2, N2, O2 |
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233
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| Hydrogen
Pumping |
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|
235
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| The
Pumping of Hydrocarbons |
|
|
240
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| Pumping
Speeds for Gases and Gas Mixtures |
|
|
241
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| 4.3
Sintered NEG Structures |
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|
246
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| 4.4
Advantages and Disadvantages of NEGs |
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|
248
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| Problem
Set |
|
|
249
|
| References |
|
|
251
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|
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| 5 CRYOPUMPING |
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|
255
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| 5.0
Introduction |
|
|
255
|
| 5.1
Cryocondensation vs. Cryosorption |
|
|
255
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| 5.1.1
Cryocondensation Pumping |
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|
257
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| 5.1.2
The Clausius-Claperon Equation |
|
|
258
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| Condensation
at Higher Pressures |
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|
260
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| 5.1.3
Thermal Transpiration |
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|
261
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| 5.1.4
Adsorption Isotherms |
|
|
264
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| Classification
of Adsorption Isotherms |
|
|
267
|
| He
and Hydrogen Isotherms on 4.2°K Surfaces |
|
|
271
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| 5.1.5
Speed and Capacity of Cryopumps |
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|
274
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| 5.1.6
Cryotrapping |
|
|
276
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| 5.1.7
Sieve Materials |
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|
277
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| Plugging
of Sieve Materials |
|
|
279
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| Surface
Bonding of Sieve Materials |
|
|
283
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| 5.2
Sorption Roughing Pumps |
|
|
284
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| 5.2.1
Staging of Sorption Pumps |
|
|
287
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| Effects
of Neon When Rough Pumping |
|
|
291
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| 5.2.2
Dewars and Bakeout Regeneration Heaters |
|
|
292
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| 5.2.3
Safety Considerations |
|
|
293
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| 5.3
Liquid Helium Cryopumps |
|
|
295
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| 5.3.1
Classification of LHe Cryopumps |
|
|
295
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| 5.3.2
Chevron Design |
|
|
299
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| 5.4
Closed-Loop Gaseous Helium Cryopumps |
|
|
301
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| Chevron
Design |
|
|
303
|
| Sticking
Coefficients |
|
|
306
|
| Thermal
Loading of Cryopumps |
|
|
307
|
| Sputtering
Applications |
|
|
309
|
| Cryopump
Applications |
|
|
312
|
| System
Configurations |
|
|
313
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| Regeneration
of Cryopumps |
|
|
315
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| Standard
& Quick Regeneration Methods |
|
|
316
|
| Reverse
Cycle Regeneration |
|
|
318
|
| The
Placebo Effect |
|
|
319
|
| Sources
& Remedies of He Gas Contamination |
|
|
320
|
| 5.5
Closed-Loop, Gaseous Helium Refrigerators |
|
|
321
|
| Some
History |
|
|
321
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| The
GM-Cycle Refrigerator |
|
|
323
|
| The
Expander |
|
|
323
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| The
Compressor |
|
|
326
|
| Refrigerator
Capacity |
|
|
329
|
| Networking
Cryopumps on Complex Systems |
|
|
329
|
| 5.5.4
Meissner Coils & Traps Using Vapor Refrigerants |
|
|
331
|
|
|
| Problem
Set |
|
|
331
|
| References |
|
|
334
|
|
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| SUBJECT INDEX |
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345
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| AUTHOR INDEX |
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353
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