Portable X-Ray Fluorescence Spectrometry: Capabilities for in Situ Analysis Book

Chapter 1 Introduction, Analytical Instrumentation and Application Overview Philip J. Potts

1.1 Portable X-ray Fluorescence 1

1.2 Techniques Capable of In Situ Portable Analytical Measurements 2

1.2.1 Spark Source Optical Emission Spectrometry 2

1.2.2 Gamma Spectrometry 2

1.2.3 Chemical Test Kits 4

1.2.4 Laser-Induced Breakdown Spectroscopy (LIBS) 4

1.2.5 Portable X-ray Fluorescence 4

1.3 PXRF Instrumentation 5

1.3.1 Excitation Sources 5

1.3.2 Sampling Positioning 7

1.3.3 Detectors 8

1.3.4 Pulse Processing and Data Analysis 9

1.4 Modes of Operation 10

1.5 Applications 11

1.5.1 Interactive Sampling and Analysis 11

1.5.2 Judgemental Sampling and Analysis 11

1.5.3 Conventional Sampling and Analysis Not Possible 12

Reference 12

Chapter 2 Quantification and Correction Procedures Andrzej A. Markowicz

2.1 Overview 13

2.2 Introduction 13

2.2.1 Types of X-ray Fluorescence Technique 15

2.2.2 Scattering of Primary Radiation 16

2.3 General Considerations 17

2.3.1 Critical Penetration Depth 18

2.3.2 Analytical Parameters of XRF Analysis 18

2.3.3 Total Uncertainty of In Situ XRF Measurements 20

2.4 Factors Influencing Accuracy 21

2.4.1 Physical Matrix Effects 21

2.4.2 Chemical Matrix Effects 24

2.4.3 Spectral Interferences 24

2.5 Correction Procedures for Physical Matrix Effects 25

2.5.1 Correction for Surface Irregularity Effects 25

2.5.2 Correction for Mineralogy Effects 26

2.6 Correction Procedures for Chemical Matrix Effects 27

2.6.1 Analysis of Thin Samples 28

2.6.2 Analysis of Intermediate Thickness Samples 28

2.6.3 Analysis of Thick Samples 30

2.6.4 Other Methods Applied for the Chemical Matrix Effects Correction35

References 36

Chapter 3 Contaminated Land: Cost-effective Investigation within Sampling Constraints Michael Ramsey

3.1 Introduction 39

3.2 Typical In Situ Applications of PXRF 40

3.3 Advantages and Disadvantages of In Situ PXRF 41

3.4 Uncertainty in PXRF Measurements 44

3.5 Factors Controlling the Precision, and hence Detection Limits 50

3.6 Less Obvious Advantages and Disadvantages of In Situ PXRF 52

3.7 Future Developments 53

References 54

Chapter 4 Coatings, Paint and Thin Film Deposits Stanislaw Piorek

4.1 Introduction 56

4.2 What is a Coating? 56

4.2.1 Brief Overview of Major Non-destructive Methods of Coating Thickness Measurement 57

4.3 XRF Method for Coating Thickness 60

4.3.1 Theory 60

4.4 Selection of Optimum Analytical Conditions 64

4.4.1 Coating Range and Excitation Source 66

4.4.2 Sensitivity and Precision of Measurement 66

4.5 Typical Examples 68

4.6 Special Cases of Coating Measurements 71

4.6.1 Lead in Applied Paint 71

4.6.2 Air Particulates on Filter 73

4.7 Summary and Conclusions 79

References 80

Chapter 5 Hazardous Substances in the Workplace Margaret West

5.1 Introduction to Occupational Hygiene 83

5.2 Routes for Exposure 84

5.2.1 Inhalation 84

5.2.2 Dermal Exposure 85

5.2.3 Oral Exposure 85

5.3 Sampling 85

5.3.1 Air 86

5.3.2 Dermal Contamination 89

5.3.3 Contaminated Surfaces 89

5.4 Theoretical Considerations 90

5.4.1 Specimen Layer Depth 90

5.4.2 Particle Size 92

5.4.3 Background Blanks 92

5.5 Measurements in the Workplace 93

5.5.1 Air Monitoring 93

5.5.2 Contaminated Surfaces 95

5.6 Conclusion 96

References 96

Chapter 6 Alloy Identification and Analysis with a Field-Portable XRF Analyser Stanislaw Piorek

6.1 Introduction 98

6.1.1 Rationale behind Analysis of Alloys in the Field 98

6.1.2 Existing Methods of Alloys Identification and XRF Analysis 101

6.2 Addressing the Problem of Alloy Identification 102

6.2.1 Defining the Task 102

6.2.2 Solutions 103

6.3 Analytical Approach 106

6.3.1 Quantitative Assaying Schemes used in XRF Analysis of Alloys 108

6.3.2 Qualitative Identification and Sorting of Alloys 114

6.3.3 Pass/Fail Sorting 116

6.3.4 Type Calibration 116

6.5 Modern, Field-Portable XRF Analyser for Alloys 117

6.5.1 Hardware Considerations 117

6.5.2 Software 118

6.5.3 Commercially Available Instruments - Feature Comparison 121

6.5.4 Typical Performance Data 122

6.6 Practical Issues to Consider 132

6.6.1 Radioisotope or X-ray Tube Excitation? 132

6.6.2 Sample Condition 136

6.7 Summary and Conclusions 138

Acknowledgements 138

References 138

Chapter 7 Geochemical Prospecting Ge Liangquan

7.1 Introduction 141

7.2 In Situ PXRF Analysis 142

7.2.1 Natural Soil 142

7.2.2 Natural Rock 148

7.2.3 Drill Core and Borehole Logging 152

7.2.4 Sediments 155

7.3 Prepared Soil and Rock Samples 157

7.4 Applications in Mining 159

7.5 Applications in Mineral Processing 166

References 172

Chapter 8 The Application of Portable X-Ray Fluorescence Analysis to Archaeological Lithic Provenancing Olwen Williams-Thorpe

8.1 Introduction 174

8.1.1 Background and Early Applications of PXRF in Archaeology 175

8.2 Instrumental, Practical and Analytical Considerations in Field and Museum Applications of PXRF 176

8.2.1 Instrumentation and its Suitability for Silicate Lithic Analysis 176

8.2.2 Practical and Analytical Considerations Important for Field and Museum Applications of PXRF 177

8.3 Applications 182

8.3.1 British Neolithic and Bronze Age Stone Axes 182

8.3.2 Roman Imperial Porphyry 192

8.3.3 Roman Granite Columns 194

8.4 Assessment of the Contribution of PXRF to Lithic Provenancing, and Comment on its Future Potential 200

Acknowledgements 203

References 203

Chapter 9 Portable Systems for Energy-Dispersive X-Ray Fluorescence Analysis of Works of Art Roberto Cesareo Stefano Ridolfi Maurizio Marabelli Alfredo Castellano Giovanni Buccolieri Marina Donativi Giovanni E. Gigante Antonio Brunetti Marco A. Rosales Medina

9.1 Introduction 206

9.2 Theoretical Background 207

9.2.1 Thick Samples 207

9.2.2 Thin Samples 209

9.2.3 Thickness Measurement in the Case of Thin Layers 210

9.3 Objects, their Preparation and Elements that can be Analysed 213

9.4 Instrumentation for PXRF Analysis 216

9.4.1 Radiation Sources 216

9.4.2 X-ray Detectors 217

9.4.3 Multi-channel Analyser 218

9.4.4 Capillary Collimators 218

9.5 Experimental Set-Up 219

9.6 Results 219

9.6.1 Bronze Statues 219

9.6.2 Mural Paintings 229

9.6.3 Gold Artefacts 231

9.6.4 Paintings 235

9.7 Conclusions 243

Acknowledgements 243

References 243

Chapter 10 Extraterrestrial Analysis: Planetary X-Ray Fluorescence from Orbiting Spacecraft and Landers G.W. Fraser

10.1 Introduction 247

10.2 In Situ XRF Analysis of Planetary Surfaces 248

10.2.1 Instrumentation Principles 248

10.2.2 Missions 251

10.2.3 Future Developments 256

10.3 X-Ray Remote Sensing of Planetary Surfaces 257

10.3.1 Sources of Primary Excitation 258

10.3.2 Non-imaging and Imaging Instruments 261

10.3.3 Missions 265

Acknowledgements 274

References 274