Capture Pumping Technology (eBook)

K. Welch (Herausgeber)

eBook Download: PDF

2001 | 2. Auflage
384 Seiten
Elsevier Science (Verlag)
978-0-08-052848-9 (ISBN)

Infos

This is a practical textbook written for use by engineers, scientists and technicians. It is not intended to be a rigorous scientific treatment of the subject material, as this would fill several volumes. Rather, it introduces the reader to the fundamentals of the subject material, and provides sufficient references for an in-depth study of the subject by the interested technologist. The author has a lifetime teaching credential in the California Community College System. Also, he has taught technical courses with the American Vacuum Society for about 35 years. Students attending many of these classes have backgrounds varying from high-school graduates to Ph.D.s in technical disciplines. This is an extremely difficult class profile to teach. This book still endeavors to reach this same audience. Basic algebra is required to master most of the material. But, the calculus is used in derivation of some of the equations. The author risks use of the first person I, instead of the author, and you instead of the reader. Both are thought to be in poor taste when writing for publication in the scientific community. However, I am writing this book for you because the subject is exciting, and I enjoy teaching you, perhaps, something new. The book is written more in the vein of a one-on-one discussion with you, rather than the author lecturing to the reader. There are anecdotes, and examples of some failures and successes I have had over the last forty-five years in vacuum related activities, I'll try not to understate either.
Lastly, there are a few equations which if memorised will help you as a vacuum technician. There are less than a dozen equations and half that many rules of thumb to memorize, which will be drawn on time an again in designing, operating and trouble-shooting any vacuum system.

Inhalt

Cover 1
Table of Contents 8
Preface 13
Biographical Note 14
Acknowledgements 15
CHAPTER 1. BASIC THEORY 16
1.0 Introduction, Pump Classification 16
1.1 Pump Capacity 16
1.2 Understanding Pump Behavior 16
1.3 The Ideal Gas Assumptions 17
1.4 Definitions of Temperature and Pressure 17
1.5 Counting Molecules (or Atoms) 20
1.6 Density, Pressure and Molecular Velocities 21
1.7 Vapor Pressure 23
1.8 Mean Free Path 27
1.9 Thermal Conductivity of Gases 30
1.10 Pumping Speed, a Convenient Abstraction 32
1.11 Throughput 34
1.12 Conductance, Another Convenient Abstraction 35
1.13 Voltage, Current and Impedance Analogies 40
1.14 Dalton's Law and Linear Superposition 43
1.15 Selective and Variable Pumping Speed 47
1.16 Measuring Pump Speed 48
1.17 System Diagnostics With Any Pump 57
1.18 Electrical Discharges in Gases 59
1.19 Vacuum Seals 77
1.20 Comments on Helium Leak Detection 86
Problem Set 91
References 93
CHAPTER 2. SPUTTER-ION PUMPING 98
2.0 Introduction 98
2.1 The Penning Cell 99
2.2 I + /P Characteristics in Penning Cells 101
2.3 Pumping Speed Abstraction 108
2.4 The Making of Sputter-Ion Pumps 109
2.5 Hydrogen Pumping 134
2.6 Triode Pumping 153
2.7 Transient Speed Effects 157
2.8 Pumping Gas Mixtures 158
2.9 High Pressure Operation 160
2.10 The Sputter-lon Pumping of Helium 164
2.11 Pumping Elements Located in Antechambers or Pockets 169
2.12 Pump Power Supplies 173
2.13 Magnet Designs 175
2.14 More on the Nature of Penning Discharges 179
2.15 Other Considerations 188
2.16 A Summary of Advantages and Disadvantages 190
Problem Set 194
References 196
CHAPTER 3. TITANIUM SUBLIMATION PUMPING 210
3.0 Introduction 210
3.1 Sticking Coefficients 211
3.2 Pump Speed vs. Sticking Coefficient 215
3.3 Synthesis, Displacement and Dissociation of Gases 223
3.4 Sublimation Sources 225
3.5 Combination Pumping 235
3.6 Advantages and Disadvantages of TSP Pumping 237
Problem Set 238
References 239
CHAPTER 4. NONEVAPORABLE GETTERS (NEG) 244
4.0 Introduction 244
4.1 Mechanical Features 244
4.2 NEG Pumping Mechanisms 247
4.3 Sintered NEG Structures 261
4.4 Advantages and Disadvantages of NEGs 263
Problem Set 264
References 266
CHAPTER 5. CRYOPUMPING 270
5.0 Introduction 270
5.1 Cryocondensation vs . Cryosorption 270
5.2 Sorption Roughing Pumps 299
5.3 Liquid Helium Cryopumps 310
5.4 Closed-Loop, Gaseous Helium Cryopumps 316
5.5 Closed-Loop, Gaseous Helium Refrigerators 336
Problem Set 346
References 349
AUTHOR INDEX 368
SUBJECT INDEX 360

Produkt-Details

• Erscheint lt. Verlag: 11.10.2001
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Strömungsmechanik
• Themenwelt: Technik ► Bauwesen
• Themenwelt: Technik ► Maschinenbau
• ISBN-10: 0-08-052848-1 / 0080528481
• ISBN-13: 978-0-08-052848-9 / 9780080528489