ELECTRON BEAM MICROANALYSIS - PART II: EXPERIMENTAL CONSIDERATIONS AND QUANTITATIVE ANALYSIS

THIS IS THE CONCLUSION OF A TWO-PART ARTICLE BEGUN IN THE NOVEMBER 1971 ISSUE. WITH RESPECT TO THE MEASUREMENT OF X- RAY INTENSITY RATIOS, THE MOST EXPENDITIOUS MEANS OF PRODUCING ACCURATE AND PRECISE MEASUREMENT WITH AN ELECTRON PROBE IS USE OF ASTUTE ANALYST WITH A KNOWLEDGE OF THE MANY ARTEFACTS AND POSSIBLE SOURCES OF ERROR. THE LATTER IS ESPECIALLY IMPORTANT, AND FAMILIARITY WITH THE LITERATURE ON THIS SUBJECT IS IMPERATIVE. TODAY EVEN SMALL ERRORS (0.5-1%) ARE A REAL SOURCE OF INACCURACY, AND EXPERIMENTS MUST BE SET UP ACCORDINGLY. THE FOLLOWING MATTERS ARE TO BE CONSIDERED IN THIS REGARD: THEORETICAL PRECISION; SPECIMEN PREPARATION, COATING, AND OXIDATION; CARBON CONTAMINATION; ELECTRON-BEAM- INDUCED CHANGES IN CONCENTRATION; ORIENTATION AND DENSITY EFFECTS; UNCERTAINTY IN STANDARDS; OPTICAL VS. SPECTROMETER DEPTH OF FOCUS; CHEMICAL INHOMOGENEITY; EFFECT OF CHEMICAL BONDING ON EMISSION; SPECTRAL INTERFERENCE AND SPECTROMETER POSITIONING; UNCERTAINTY IN THE ACCELERATION POTENTIAL; DRIFT, BACKGROUND, AND DEADTIME; ANALYTICAL X-RAY VOLUME; BASE LINE CLIPPING; AND INSTRUMENT STOPPING POWER. ALTHOUGH THE CONVERSION OF EXPERIMENTALLY OBSERVED X-RAY INTENSITY RATIOS INTO TRUE CHEMICAL COMPOSITIONS HAS BEEN THE SUBJECT OF A MASSIVE LITERATURE, THE ELEMENTS OF THE THEORY ARE INCLUDED HERE TO PROVIDE A TIDY SUMMARY AND PRACTICAL GUIDE FOR THOSE WHO ARE NOT INTIMATELY ACQUAINTED WITH THE THEORY OF QUANTITATIVE ANALYSIS. A TABLE PRESENTS AN HISTORICAL SUMMARY OF THE QUALITATIVE ANALYSIS CAPABILITY OF THE ELECTRON PROBE ANALYZER, AND COMPUTER PROGRAMS FOR CONVERTING X-RAY INTENSITY RATIOS TO CHEMICAL COMPOSITION ARE REVIEWED.

• Supplemental Notes:
  • Vol 11, No 12, PP 12-31, 51-56, 13 FIG, 12 TAB, 100 REF
• Authors:
  • Beaman, D R
  • Isasi, J A
• Publication Date: 1971-12

Media Info

• Serial:
  • Materials Research and Standards
  • Publisher: American Society for Testing and Materials (ASTM)

Subject/Index Terms

• TRT Terms: Chemical composition; Electron beams; Electrons; Microanalysis; Probes (Measuring devices); Quantitative analysis; X rays
• Uncontrolled Terms: Experimental design
• Old TRIS Terms: Electron probes
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00217179
• Record Type: Publication
• Files: TRIS
• Created Date: May 1 1972 12:00AM