Laser-Induced Breakdown Spectroscopy (eBook)

Front Cover 1
Laser-Induced Breakdown Spectroscopy 4
Copyright page 5
Table of Contents 6
Preface 14
Contributors 18
Acronyms 22
PART I BASIC PHYSICS AND INSTRUMENTATION 26
Chapter 1. Fundamentals of LIBS 28
1. Introduction 28
2. Lasers for LIBS 29
2.1. Mode Properties of Lasers 30
2.2. Spatial Intensity Distribution and Focusing of Laser Beam 31
2.3. Time Behavior of Laser Pulses 32
2.4. Measurement of Laser Power and Energy 33
2.5. Varieties of Lasers 34
3. Laser Induced Plasmas 35
3.1. Laser Induced Breakdown in Gases 35
3.2. Plasma Production from Solid Targets 37
3.3. Radiation from Laser Induced Plasmas 39
4. Progress in Detection of LIBS 40
4.1. CCD and ICCD Detectors 41
4.2. The Spectrograph-Detector Combination 42
5. Applications of LIBS 43
References 44
Chapter 2. Atomic Emission Spectroscopy 48
1. Introduction 48
2. Measurement of Spectral Lines 49
3. Electronic Structure of Atoms 50
3.1. Hydrogenic Atoms 51
3.2. Many Electron Atoms 51
3.3. Classification of Electronic States 53
4. Radiation From Atoms 54
4.1. Electric Dipole Selection Rules 55
4.2. Parity Selection Rules 57
4.3. Forbidden Transitions 57
4.4. Line Strength 58
4.5. Oscillator Strength 58
4.6. Intensities of Spectral Lines 60
4.7. Continuous Emission & Bremsstrahlung
5. Broadening of Spectral Lines 62
5.1. Stark Broadening 63
5.2. Theory of Stark Effect 63
6. Applications 66
6.1. Determination of Electron Temperature 66
6.2. Determination of the Electron Density 69
6.3. Qualitative Emission Analysis 70
6.4. Quantitative Emission Analysis 72
References 73
Chapter 3. Laser Ablation 74
1. Introduction 74
2. Fundamental Ablation Processes 75
2.1. Plasma Ignition Processes 77
2.2. Plasma Expansion Processes 83
2.3. Plasma Emission Spectra 85
2.4. Electron Density and Plasma Temperature 87
3. Particle Formation Processes 90
3.1. Particle Ejection 90
3.2. Nanoparticle Formation 91
4. Laser Ablation Parameters 91
4.1. Nanosecond Pulsed Lasers 92
5. Picosecond Pulsed Lasers 98
6. Femtosecond Pulsed Lasers 100
7. Perspectives, Future and Trends 103
References 104
Chapter 4. Physics of Plasma in LIBS 108
1. Introduction 108
2. Basics of Laser-Matter Interaction 109
3. Processes in Laser Produced Plasma 110
4. Spectral Emission from Plasma 111
4.1. Continuum Emission 112
4.2. Line Emission 112
4.3. Temporal and Spatial Resolution of Emission 112
5. Theoretical Models For Plasma 113
5.1. Corona Model 113
5.2. Local Thermodynamic Equilibrium Model 114
5.3. Collisional Radiative Model 114
6. Measurement of Plasma Parameters 115
6.1. Line Broadening 116
6.2. Electron Density 117
6.3. Plasma Temperature 118
6.4. Optical Thickness and Self-absorption 119
7. Characteristics of LIBS Plasma 119
8. Factors Affecting the LIBS Plasma 121
8.1. Laser Characteristics 121
8.2. Wavelength and Pulse Duration of Laser 123
8.3. Properties of Target Material 125
8.4. Time Window of Observation 125
8.5. Geometric Set-up 127
8.6. Ambient Gas 129
9. Methods of Enhancing LIBS Sensitivity 131
10. Conclusion 132
References 133
Chapter 5. Instrumentation for LIBS 138
1. Introduction 138
2. Typical LIBS Set-up 139
3. LIBS Instrumentation 141
3.1. Echelle Spectrometer 143
3.2. Specialty of Echelle Spectrometer 144
4. Fiber Optic LIBS 146
4.1. Fiber Optic LIBS Probe 146
4.2. Transmission Property of Optical Fiber 148
5. Portable LIBS Devices 148
6. Sensitive LIBS Techniques 150
7. Variety of LIBS Instrumentation 152
7.1. Environmental Monitoring 152
7.2. LIBS in Space Research 153
7.3. LIBS in Industry 154
8. LIBS Experiments & Analytical Performance
9. Conclusion 156
References 156
PART II NEW LIBS TECHNIQUES 160
Chapter 6. Dual-Pulse LIBS 162
1. Introduction 162
2. Dual-Pulse LIBS 163
3. Dual-Pulse LIBS Applications 165
4. Dual-Pulse LIBS Mechanistic Studies 168
5. Future Directions 172
References 173
Chapter 7. Femtosecond LIBS 176
1. Chapter Organization 176
2. Introduction 176
3. Plasma Produced by Ultra-Short Laser Pulses 178
3.1. Basic Processes during Laser Ablation 179
3.2. Material Removal and Plasma Expansion 180
3.3. Influence of the Pulse duration on the Plasma Properties 183
4. Spectrochemical Analysis by Ultra-Short Laser-Induced Plasma 189
5. Non-Gated Analysis by Ultra-Short Laser Pulses 191
6. Conclusions 193
References 194
Chapter 8. Micro-LIBS 198
1. Introduction 198
2. Microjoule Laser Sources 200
2.1. Microchip Lasers 200
2.2. Microjoule Fiber Lasers 202
3. Scaling LIBS to Microjoule Energies 203
3.1. Plasma Emission and Lifetime 204
3.2. Crater Size – Lateral and Depth Resolution 206
3.3. Limits of Detection 209
3.4. Signal Linearity with Concentration 211
4. Applications 211
4.1. Microanalysis of Small Volumes 212
4.2. Scanning Microanalysis of Material Surfaces 213
4.3. Liquid Samples 218
5. Conclusions 218
References 219
Part III LIBS APPLICATIONS 222
Chapter 9. LIBS Application to Off-Gas Measurement 224
1. Introduction 224
2. Experimental Setup 225
3. Calibration 226
4. Applications 231
4.1. Analysis of Air-Sampling Filters with LIBS 231
4.2. Continuous Emission Monitor 234
4.3. Process Control 238
4.4. Filter Efficiency 239
4.5. Combustion Diagnostic 241
4.6. Rocket Engine Health Monitor 241
5. Conclusion 245
References 245
Chapter 10. LIBS of Liquid Samples 248
1. Introduction 248
2. LIBS of Liquid Samples 249
2.1. Elemental Analysis in Liquids 249
2.2. LIBS of Molten Metal 251
3. Instrumentation for Liquid Samples 252
3.1. Experimental Setup for Surface Excitation 252
3.2. Experimental Set up for Bulk/Molten Liquid 253
3.3. Liquid Configuration for Plasma Formation 254
3.4. Optimization of Experimental Parameters 255
4. Enhancement in the Sensitivity of LIBS 257
4.1. Effects of a Magnetic Field on Plasma 257
4.2. Effects of Double Laser Pulse Excitation on LIBS Signal 266
5. Conclusion 277
References 277
Chapter 11. LIBS of Solid and Molten Material 280
1. Introduction 280
2. FO LIBS Sensor for Determination of Elemental Composition of Solid Aluminum Alloys 281
2.1. Parametric Studies 282
2.2. Effect of Angle of Incidence on LIBS Signal 286
2.3. Calibration Curve 287
2.4. Effect of Sample-Lens Distance and Focal Length 294
3. LIBS Spectra of Molten Aluminum Alloy in a Laboratory Furnace 296
3.1. Effect of the Surrounding Atmosphere on LIBS Signal 298
3.2. Calibration Curves for Molten Aluminum Alloy 300
3.3. Comparison of LIBS Spectra of Molten and Solid Alloy Samples 302
4. FO-LIBS Probe for Aluminum Alloy in Industrial Pilot Furnace 305
4.1. Testing the Long Stainless Steel Probe 307
4.2. LIBS Measurements inside the Industrial Pilot Furnace 307
5. Conclusions 309
References 309
Chapter 12. LIBS Technique for Powder Materials 312
1. Introduction 312
2. LIBS Technique for Powder Materials 313
2.1. Preparation of the Pellets of the Powder Samples 314
2.2. Apparatus 316
2.3. Position of the Focal Spot 317
2.4. Delay Time 318
2.5. Sample Rotating Speed 318
3. Application to Pharmaceutical Industry 319
3.1. Introduction 319
3.2. Analysis of Organic Materials 320
3.3. Experimental Approaches 322
3.4. Main Applications 324
4. Prospects: LIBS as a Process Analytical Technology 329
5. Application to Glass Industry 329
References 335
Chapter 13. LIBS for the Analysis of Chemical and Biological Hazards 338
1. Introduction 338
2. Application to Chemical Hazard Analysis 339
3. Application to Bio-Aerosol & Bio-Agent Detection
3.1. Deposited or Pelletized Samples 341
3.2. Airborne samples 345
4. Conclusion 348
References 348
Chapter 14. Life Science Applications of LIBS 350
1. Introduction 350
2. Bone & Tooth Analysis
3. Hair & Nail Analysis
4. Blood Analysis 355
5. Urine Stones Analysis 356
6. Tissue Analysis 357
7. Conclusions 362
References 363
Chapter 15. Measurement of Carbon for Carbon Sequestration and Site Monitoring 366
1. Introduction 366
2. LIBS Measurements in Soil 367
3. Carbon-Nitrogen Analysis by Sample Combustion 369
4. Acid Washing of Soils to Remove Inorganic Carbon 369
5. Field Measurements 374
6. Conclusions 374
References 375
Chapter 16. Remote Analysis by LIBS: Application to Space Exploration 378
1. Introduction 378
2. Conventional Stand-off LIBS 379
2.1. Apparatus 380
2.2. Results 381
3. Stand-off LIBS Using Femtosecond Pulses 383
3.1. Femtosecond Laser Pulses and LIBS 383
3.2. Remote Sensing using fs Pulse Produced Filamentation 384
3.3. Teramobile 386
3.4. Remote LIBS using fs Pulses 386
4. Stand-off LIBS for Space Exploration 387
4.1. Spectroscopic Methods of Planetary Analysis 388
4.2. Prior Elemental Analysis Methods used on Landers/Rovers 388
4.3. Advantages 390
4.4. LIBS Characteristics for Stand-off Analysis 393
4.5. Capabilities 397
4.6. Instrumentation 401
References 403
Chapter 17. LIBS for Aerosol Analysis 406
1. Introduction 406
2. Fundamentals of Aerosol Analysis 406
3. Laser Induced Breakdown of Gases 408
4. Analysis of Aerosol Particles by LIBS 411
4.1. Spectral Ensemble-Averaging 412
4.2. Statistical Aerosol Sampling with LIBS 418
4.3. Conditional Analysis for Spectral Processing 421
4.4. Analysis of Individual Aerosol Particles 427
5. Alternative Methodologies for Aerosol Analysis 429
6. Applications of LIBS-Based Aerosol Analysis 430
7. Future Directions 435
References 438
Chapter 18. Scope of Future Development in LIBS 444
1. Introduction 444
2. Gas Phase LIBS 444
3. Liquid Phase LIBS 445
4. Solid Phase LIBS 445
5. LIBS of Molten Samples 446
6. Theoretical Models of Laser Induced Plasma 446
7. Commercialization of LIBS 447
8. Future Applications 447
References 449
Subject Index 452