Preface ....................................................... xix
List of abbreviations ......................................... xxi
1 Basic principles of reliability, human error, and other
general issues ............................................. 1
1.1 Introduction ............................................... 1
1.2 Central points ............................................. 1
1.3 Human factors .............................................. 5
1.3.1 General methods and habits .......................... 5
1.3.2 Data on human error ................................. 8
1.3.3 Some ways of reducing human error .................. 11
1.3.4 Interpersonal and organizational issues ............ 20
1.4 Laboratory procedures and strategies ...................... 24
1.4.1 Record-keeping ..................................... 24
1.4.2 Maintenance and calibration of equipment ........... 25
1.4.3 Troubleshooting equipment and software ............. 25
1.5 Reliability of information ................................ 28
Further reading ........................................... 31
Summary of some important points .......................... 31
References ................................................ 34
2 Mathematical calculations ................................. 36
2.1 Introduction .............................................. 36
2.2 Sources and kinds of error ................................ 36
2.2.1 Conceptual problems ................................ 36
2.2.2 Transcription errors ............................... 36
2.2.3 Errors in technique ................................ 36
2.2.4 Errors caused by subconscious biases ............... 38
2.2.5 Errors in published tables ......................... 38
2.2.6 Problems arising from the use of computer algebra
systems ............................................ 39
2.2.7 Errors in numerical calculations ................... 40
2.3 Strategies for avoiding errors ............................ 42
2.3.1 Avoiding conceptual difficulties ................... 42
2.3.2 Use of diagrams .................................... 42
2.3.3 Notation ........................................... 43
2.3.4 Keeping things simple .............................. 43
2.3.5 Use of modularity .................................. 44
2.3.6 Finding out what is known .......................... 44
2.3.7 Outsourcing the problem ............................ 44
2.3.8 Step-by-step checking and correction ............... 45
2.3.9 Substitution of numbers for variables .............. 45
2.3.10 Practices for manual calculations .................. 45
2.3.11 Use of computer algebra software ................... 46
2.3.12 Avoiding transcription errors ...................... 46
2.4 Testing for errors ......................................... 46
2.4.1 General remarks .................................... 46
2.4.2 Getting the correct result for the wrong reason .... 47
2.4.3 Predicting simple features of the solution from
those of the problem ............................... 47
2.4.4 Dimensional analysis ............................... 48
2.4.5 Further checks involving internal consistency ...... 48
2.4.6 Existence of a solution ............................ 49
2.4.7 Reasonableness of the result ....................... 49
2.4.8 Check calculations ................................. 49
2.4.9 Comparing the results of the calculation against
known results ...................................... 51
2.4.10 Detecting errors in computer algebra calculations .. 52
Summary of some important points .......................... 53
References ................................................ 55
3 Basic issues concerning hardware systems .................. 58
3.1 Introduction .............................................. 58
3.2 Stress derating ........................................... 58
3.3 Intermittent failures ..................................... 60
3.3.1 Introduction ....................................... 60
3.3.2 Some causes and characteristics .................... 60
3.3.3 Preventing and solving intermittent problems ....... 62
3.4 Effects of environmental conditions ....................... 63
3.4.1 Excessive laboratory temperatures and the cooling
of equipment ....................................... 63
3.4.2 Moisture ........................................... 65
3.5 Problems caused by vibrations ............................. 68
3.5.1 Introduction ....................................... 68
3.5.2 Large-amplitude vibration issues ................... 69
3.5.3 Interference with measurements ..................... 71
3.6 Electricity supply problems ............................... 83
3.6.1 Definitions and causes of power disturbances ....... 83
3.6.2 Investigating power disturbances ................... 85
3.6.3 Measures for preventing a.c. power problems ........ 86
3.7 Damage and deterioration caused by transport .............. 91
3.7.1 Common difficulties ................................ 91
3.7.2 Conditions encountered during transport ............ 91
3.7.1 Packaging for transport ............................ 93
3.7.4 Specialist companies for packaging and
transporting delicate equipment .................... 95
3.7.5 Insurance .......................................... 95
3.7.6 Inspection of received items ....................... 96
3.7.7 Local transport of delicate items .................. 96
3.8 Some contaminants in the laboratory ....................... 96
3.8.1 Corrosive atmospheres in chemical laboratories ..... 96
3.8.2 Oil and water in compressed air supplies ........... 96
3.8.3 Silicones .......................................... 97
3.9 Galvanic and electrolytic corrosion ....................... 99
3.10 Enhanced forms of materials degradation related to
corrosion ................................................ 100
3.11 Fatigue of materials ..................................... 101
3.11.1 Introduction ...................................... 101
3.11.2 Prevalence and examples of fatigue ................ 101
3.11.3 Characteristics and causes ........................ 102
3.11.4 Preventive measures ............................... 104
3.12 Damage caused by ultrasound .............................. 104
Summary of some important points ......................... 105
References ............................................... 111
4 Obtaining items from commercial sources .................. 116
4.1 Introduction ............................................. 116
4.2 Using established technology and designs ................. 116
4.3 The importance of standards .............................. 117
4.4 Understanding the basics of a technology ................. 117
4.5 Price and quality ........................................ 118
4.6 Choice of manufacturers and equipment .................... 119
4.6.1 Reliability assessments based on experiences of
product users ..................................... 119
4.6.2 Place of origin of a product ...................... 119
4.6.3 Specialist vs. generalist manufacturers ........... 120
4.6.4 Limitations of ISO9001 and related standards ...... 120
4.6.5 Counterfeit parts ................................. 120
4.6.6 True meaning of specifications .................... 120
4.6.7 Visiting the manufacturer's facility .............. 121
4.6.8 Testing items prior to purchase ................... 121
4.7 Preparing specifications, testing, and transport and
delivery ................................................. 122
4.7.1 Preparing specifications for custom-made
apparatus ......................................... 122
4.7.2 Documentation requirements ........................ 122
4.7.3 Reliability incentive contracts ................... 122
4.7.4 Actions to take before delivery ................... 123
4.7.5 Acceptance trials for major equipment ............. 124
4.8 Use of manuals and technical support ..................... 124
Summary of some important points ......................... 125
References ............................................... 126
5 General points regarding the design and construction
of apparatus ............................................. 127
5.1 Introduction ............................................. 127
5.2 Commercial vs. self-made items ........................... 127
5.3 Time issues .............................................. 128
5.4 Making incremental advances in design .................... 129
5.5 Making apparatus fail-safe ............................... 129
5.6 The use of modularity in apparatus design ................ 130
5.7 Virtual instruments ...................................... 131
5.8 Planning ahead ........................................... 132
5.9 Running the apparatus on paper before beginning
construction ............................................. 133
5.10 Testing and reliability .................................. 134
5.11 Designing apparatus for diagnosis and maintainability .... 134
5.12 Design for graceful failure .............................. 135
5.13 Component quality ........................................ 135
5.14 Ergonomics and aesthetics ................................ 135
Further reading .......................................... 136
Summary of some important points ......................... 136
References ............................................... 137
6 Vacuum-system leaks and related problems ................. 138
6.1 Introduction ............................................. 138
6.2 Classifications of leak-related phenomena ................ 139
6.3 Common locations and circumstances of leaks .............. 140
6.4 Importance of modular construction ....................... 141
6.5 Selection of materials for use in vacuum ................. 142
6.5.1 General points .................................... 142
6.5.2 Leak testing raw materials ........................ 143
6.5.3 Stainless steel ................................... 144
6.5.4 Brass ............................................. 146
6.5.5 Phosphor bronze ................................... 146
6.5.6 Copper-nickel ..................................... 146
6.5.7 Copper ............................................ 146
6.5.8 Aluminum .......................................... 147
6.6 Some insidious sources of contamination and outgassing ... 147
6.6.1 Cleaning agents ................................... 147
6.6.2 Vacuum-pump fluids and substances ................. 148
6.6.3 Vacuum greases .................................... 149
6.6.4 Other type of contamination ....................... 149
6.6.5 Some common causes of contamination in UHV
systems ........................................... 150
6.7 Joining procedures: welding, brazing, and soldering ...... 150
6.7.1 Worker qualifications and vacuum joint leak
requirements ...................................... 150
6.7.2 General points .................................... 151
6.7.3 Reduced joint-count designs and monolithic
construction ...................................... 154
6.7.4 Welding ........................................... 154
6.7.1 Brazing ........................................... 157
6.7.6 Soldering ......................................... 158
6.8 Use of guard vacuums to avoid chronic leak problems ...... 164
6.9 Some particularly trouble-prone components ............... 165
6.9.1 Items involving fragile materials subject to
thermal and mechanical stresses ................... 165
6.9.2 Water-cooled components ........................... 166
6.9.3 Metal bellows ..................................... 167
6.9.4 Vacuum gauges ..................................... 170
6.10 Diagnostics .............................................. 170
6.10.1 Leak detection ................................... 170
6.10.2 Methods of detecting and identifying
contamination .................................... 179
6.11 Leak repairs ............................................. 179
Summary of some important points ......................... 181
References ............................................... 187
7 Vacuum pumps and gauges, and other vacuum-system
concerns ................................................. 190
7.1 Introduction ............................................. 190
7.2 Vacuum pump matters ...................................... 190
7.2.1 Primary pumps ..................................... 190
7.2.2 High-vacuum pumps ................................. 195
7.3 Vacuum gauges ............................................ 207
7.3.1 General points .................................... 207
7.3.2 Pirani and thermocouple gauges .................... 208
7.3.3 Capacitance manometers ............................ 208
7.3.4 Penning gauges .................................... 209
7.3.5 Bayard-Alpert ionization gauges ................... 209
7.4 Other issues ............................................. 210
7.4.1 Human error and manual valve operations ........... 210
7.4.2 Selection of bakeout temperatures for UHV
systems ........................................... 211
7.4.3 Cooling of electronics in a vacuum ................ 212
Further reading .......................................... 213
Summary of some important points ......................... 213
References ............................................... 216
8 Mechanical devices and systems ........................... 218
8.1 Introduction ............................................. 218
8.2 Mechanical devices ....................................... 218
8.2.1 Overview of conditions that reduce reliability .... 218
8.2.2 Some design approaches for improving mechanism
reliability ....................................... 219
8.2.3 Precision positioning devices in optical systems .. 223
8.2.4 Prevention of damage due to exceeding mechanical
limits ............................................ 224
8.2.5 Bearings .......................................... 224
8.2.6 Gears in vacuum environments ...................... 227
8.2.7 Lubrication and wear under extreme conditions ..... 227
8.2.1 Static demountable seals .......................... 233
8.2.9 Dynamic seals and motion feedthroughs ............. 246
8.2.10 Valves ............................................ 250
8.3 Systems for handling liquids and gases ................... 260
8.3.1 Configuration of pipe networks .................... 260
8.3.2 Selection of materials ............................ 260
8.3.3 Construction issues ............................... 261
8.3.4 Problems caused by PTFE tape ...................... 262
8.3.5 Filter issues ..................................... 262
8.3.6 Detection and location of leaks ................... 263
8.4 Water-cooling systems .................................... 263
8.4.1 Introduction ...................................... 263
8.4.2 Water leaks ....................................... 265
8.4.3 Water purity requirements ......................... 268
8.4.4 System materials selection and corrosion .......... 270
8.4.5 Condensation ...................................... 270
8.4.6 Water flow and temperature interlocks and
indicators ........................................ 271
8.4.7 Inspection of water-cooled equipment .............. 271
Further reading .......................................... 271
Summary of some important points ......................... 272
References ............................................... 280
9 Cryogenic systems ........................................ 285
9.1 Introduction ............................................. 285
9.2 Difficulties caused by the delicate nature of cryogenic
apparatus ................................................ 286
9.3 Difficulties caused by moisture .......................... 288
9.4 Liquid-helium transfer problems .......................... 289
9.5 Large pressure buildups within sealed spaces ............. 290
9.6 Blockages of cryogenic liquid and gas lines .............. 291
9.7 Other problems caused by the presence of air in
cryostats ................................................ 293
9.8 Cryogen-free low temperature systems ..................... 293
9.9 Heat leaks ............................................... 294
9.10 Thermal contact problems ................................. 296
9.10.1 Introduction ...................................... 296
9.10.2 Welded and brazed contacts ........................ 296
9.10.3 Mechanical contacts ............................... 296
9.11 IK pots .................................................. 300
9.12 Thermometry .............................................. 301
9.12.1 Two common causes of thermometer damage ........... 301
9.12.2 Measurement errors due to poor thermal
connections ....................................... 301
9.12.3 Measurement errors due to RF heating and
interference ...................................... 301
9.12.4 Causes of thermometer calibration shifts .......... 302
9.12.5 Other thermometer issues .......................... 303
9.13 Problems arising from the use of superconducting
magnets .................................................. 303
Further reading .......................................... 305
Summary of some important points ......................... 305
References ............................................... 308
10 Visible and near-visible optics .......................... 310
10.1 Introduction ........................................ 310
10.2 Temperature variations in the optical path .......... 310
10.3 Temperature changes in optical elements and
support structures .................................. 312
10.4 Materials stability ................................. 314
10.5 Etalon fringes ...................................... 315
10.6 Contamination of optical components ................. 318
10.6.1 Introduction ................................. 318
10.6.2 A closer look at some contamination-
sensitive systems and devices ................ 321
10.6.3 Measures for protecting optics ............... 323
10.6.4 Inspection ................................... 326
10.6.5 Cleaning of optical components ............... 327
10.7 Degradation of optical materials .................... 333
10.7.1 Problems with IR and UV materials caused by
moisture, and thermal and mechanical shocks .. 333
10.7.2 Degradation of materials by UV light
("solarization") ............................. 334
10.7.3 Corrosion and mold growth on optical
surfaces ..................................... 334
10.7.4 Some exceptionally durable optical
materials .................................... 335
10.8 Fiber optics ........................................ 337
10.8.1 Mechanical properties ........................ 337
10.8.2 Resistance to harsh environments ............. 337
10.8.3 Insensitivity to crosstalk and EMI, and
sensitivity to environmental disturbances .... 337
10.9 Light sources ....................................... 338
10.9.1 Noise and drift .............................. 338
10.9.2 Some lasers and their reliability issues ..... 341
10.9.3 Some incoherent light sources ................ 343
10.10 Spatial filters .................................... 344
10.11 Photomultipliers and other light detectors ......... 344
10.12 Alignment of optical systems ....................... 345
Further reading .......................................... 345
Summary of some important points ......................... 345
References ............................................... 350
11 Electronic systems ....................................... 353
11.1 Introduction ............................................. 353
11.2 Electromagnetic interference ............................. 353
11.2.1 Grounding and ground loops ........................ 353
11.2.2 Radio-frequency interference ...................... 370
11.2.1 Interference from low-frequency magnetic fields ... 379
11.2.4 Some EMI issues involving cables, including
crosstalk between cables .......................... 381
11.2.5 Professional assistance with EMI problems ......... 382
11.3 High-voltage problems: corona, arcing, and tracking ...... 382
11.3.1 The phenomena and their effects ................... 382
11.3.2 Conditions likely to result in discharges ......... 383
11.3.3 Measures for preventing discharges ................ 384
11.3.4 Detection of corona and tracking .................. 386
11.4 High-impedance systems ................................... 387
11.4.1 The difficulties .................................. 387
11.4.2 Some solutions .................................... 388
11.5 Damage and electromagnetic interference caused by
electrostatic discharge (ESD) ............................ 390
11.5.1 Origins, character; and effects of ESD ............ 390
11.5.2 Preventing ESD problems ........................... 393
11.6 Protecting electronics from excessive voltages ........... 394
11.7 Power electronics ........................................ 395
11.8 Some trouble-prone components ............................ 397
11.8.1 Switches and related devices ...................... 397
11.8.2 Potentiometers .................................... 400
11.8.3 Fans .............................................. 400
11.8.4 Aluminium electrolytic capacitors ................. 401
11.8.5 Batteries ......................................... 401
11.8.6 Low-frequency signal transformers ................. 403
Further reading .......................................... 403
Summary of some important points ......................... 404
References ............................................... 409
12 Interconnecting, wiring, and cabling for electronics ..... 413
12.1 Introduction ............................................. 413
12.2 Permanent or semi-permanent electrical contacts .......... 414
12.2.1 Soldering ......................................... 414
12.2.2 Crimping, brazing, welding, and the use of
fasteners ......................................... 422
12.2.3 Summary of methods for making contacts to
difficult materials ............................... 425
12.2.4 Ground contacts ................................... 429
12.2.5 Minimization of thermoelectric EMFs in low-level
d.c. circuits ..................................... 430
12.3 Connectors ............................................... 431
12.3.1 Introduction ...................................... 431
12.3.2 Failure modes ..................................... 431
12.3.3 Causes of connector failure ....................... 433
12.3.4 Selection of connectors ........................... 437
12.3.5 Some particularly troublesome connector types ..... 445
12.3.6 Some points concerning the use of connectors ...... 448
12.4 Cables and wiring ........................................ 451
12.4.1 Modes of failure .................................. 451
12.4.2 Cable damage and degradation ...................... 452
12.4.3 Selection of cables and cable assemblies .......... 454
12.4.4 Electromagnetic interference ...................... 456
12.4.5 Some comments concerning GP-IB and ribbon cables .. 462
12.4.6 Additional points on the use of cables ............ 463
12.4.7 Wire issues - including cryostat wiring ........... 466
12.5 Diagnostics .............................................. 471
12.5.1 Introduction ...................................... 471
12.5.2 Detection of contact problems ..................... 471
12.5.3 High-resistance and open- and short-circuit
intermittent faults ............................... 472
12.5.4 Use of infrared thermometers on high-current
contacts .......................................... 473
12.5.5 Insulation testing ................................ 474
12.5.6 Fault detection and location in cables ............ 474
12.5.7 Determining cable-shield integrity ................ 475
Summary of some important points ......................... 475
References ............................................... 482
13 Computer hardware and software, and stored information ... 487
13.1 Introduction ............................................. 487
13.2 Computers and operating systems .......................... 487
13.2.1 Selection ......................................... 487
13.2.2 Some common causes of system crashes and other
problems .......................................... 489
13.2.3 Information and technical support ................. 490
13.3 Industrial PCs and programmable logic controllers ........ 490
13.4 Some hardware issues ..................................... 491
13.4.1 Hard-disc drives .................................. 491
13.4.2 Power supplies .................................... 494
13.4.3 Mains-power quality and the use of power-
conditioning devices .............................. 495
13.4.4 Compatibility of hardware and software ............ 496
13.4.5 RS-232 and IEEE-488 (GP-IB) interfaces ............ 496
13.5 Backing up information ................................... 499
13.5.1 Introduction and general points ................... 499
13.5.2 Some backup techniques and strategies ............. 499
13.5.3 Online backup services ............................ 500
13.6 Long-term storage of information and the stability of
recording media .......................................... 500
13.7 Security issues ..................................... 502
13.7.1 General points .................................... 502
13.7.2 Viruses and their effects ......................... 502
13.7.3 Symptoms of virus infection ....................... 503
13.7.4 Measures for preventing virus attacks ............. 503
13.7.5 Network security .................................. 504
13.8 Reliability of commercial and open-source software ....... 504
13.8.1 Avoiding early releases and beta software ......... 504
13.8.2 Questions for software suppliers .................. 505
13.8.3 Pirated software .................................. 506
13.8.4 Open-source software .............................. 506
13.9 Safety-related applications of computers ................. 507
13.10 Commercial data-acquisition software .................... 507
13.10.1 Data-acquisition applications and their
properties ....................................... 507
13.10.2 Graphical languages .............................. 507
13.10.3 Some concerns with graphical programming ......... 508
13.10.4 Choosing a data-acquisition application .......... 509
13.11 Precautions for collecting experimental data over
extended periods ......................................... 509
13.12 Writing software ........................................ 510
13.12.1 Introduction ..................................... 510
13.12.2 Planning ahead - establishing code requirements
and designing the software ....................... 511
13.12.3 Detailed program design and construction ......... 514
13.12.4 Testing and debugging ............................ 523
13.13 Using old laboratory software ........................... 526
Further reading .......................................... 527
Summary of some important points ......................... 527
References ............................................... 533
14 Experimental method ...................................... 536
14.1 Introduction ............................................. 536
14.2 Knowing apparatus and software ........................... 536
14.3 Calibration and validation of apparatus .................. 537
14.4 Control experiments ...................................... 538
14.5 Failure of auxiliary hypotheses as a cause of failure
of experiments ........................................... 540
14.6 Subconscious biases as a source of error ................. 540
14.6.1 Introduction ...................................... 540
14.6.2 Some circumstances in which the effects of
biases can be especially significant .............. 541
14.6.3 Subconscious biases in data analysis .............. 541
14.6.4 Subconscious biases caused by social
interactions ...................................... 542
14.7 Chance occurrences as a source of error .................. 543
14.8 Problems involving material samples ...................... 543
14.8.1 Introduction ...................................... 543
14.8.2 The case of polywater ............................. 544
14.8.3 Some useful measures .............................. 546
14.9 Reproducibility of experimental measurements and
techniques ............................................... 547
14.9.1 Introduction ...................................... 547
14.9.2 Tacit knowledge ................................... 548
14.9.3 Laboratory visits as a way of acquiring missing
expertise ......................................... 548
14.9.4 A historical example: measuring the Q of
sapphire .......................................... 549
14.10 Low signal-to-noise ratios and statistical signal
processing .............................................. 551
14.11 Some important mistakes, as illustrated by early work
on gravity-wave detection ............................... 552
14.11.1 Introduction ..................................... 552
14.11.2 A brief outline and history ...................... 552
14.11.3 Origins of the problems .......................... 553
14.11.4 Conclusions ...................................... 557
14.12 Understanding one's apparatus and bringing it under
control: the example of the discovery of superfluidity
in He3 ................................................... 558
Further reading ............................................... 559
Summary of some important points .............................. 560
References .................................................... 562
Index ......................................................... 564
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