Front Matter

• ·Introduction

Part 1: Getting Started

• 1What XRR Fitting Is, and What It Can Tell You
• 2Meet X-Ray Calc 3
• 3Your First Fit, the Short Way

Part 2: The Physics You Need, and No More

• 4X-Rays Meet a Surface
• 5One Film: Kiessig Fringes
• 6Many Films: Bragg Peaks
• 7Roughness, Interlayers, and a Dirty Surface
• 8How X-Ray Calc Computes a Curve
• 9How X-Ray Calc Finds a Fit

Part 3: The Fitting Workflow, Step by Step

• 10Is This Curve Worth Fitting?
• 11Reading the Curve Before You Fit
• 12Building the Starting Model
• 13The Sensitivity Check: What Each Parameter Changes
• 14Preparing the Data: Scale, Smoothing, and Fitting Range
• 15Choosing What to Fit: Free Parameters and Limits
• 16Fit Settings: Resolution, Swarm Size, and Seeds
• 17Periodic or Polynomial? A Stack That Drifts
• 18Judging a Fit
• 19When the Fit Will Not Converge

Part 4: Special Cases and Reporting

• 20Density: A Free Parameter, Not a Result
• 21Single Films
• 22Graded Multilayers and Supermirrors
• 23Reporting a Fit Others Can Trust

Part 5: The Part of Tens

• 24Ten Ways a Fit Can Mislead You
• 25Ten Checks Before You Trust a Number
• 26Ten Things X-Ray Calc Does Not Fit for You

Appendices

• ANotation and Units
• BMenus, Buttons and Keys
• CWhere Optical Constants Come From
• DGlossary