The “Where’s Waldo” Dilemma in Microscopy · • Scanning Electron Microscope (SEM)with...
Transcript of The “Where’s Waldo” Dilemma in Microscopy · • Scanning Electron Microscope (SEM)with...
The “Where’s Waldo” Dilemma in Microscopy
Wayne D. NiemeyerSenior Research Scientist
November 10, 2016
Search for the Known (Waldo) in a Complex Mix of Extraneous Stuff
There he is!
Mapping Instrumentation and Methods in Microscopy
• Fluorescence Microscope
• Scanning Electron Microscope (SEM)with Energy Dispersive X‐Ray Spectrometry (EDS, aka. EDX)
• Electron Microprobe with Wavelength Dispersive X‐Ray Spectrometry (WDS, aka. WDX) and EDS
• Secondary Ion Mass Spectrometry (SIMS)
• Raman Spectroscopy
• X‐Ray Photoelectron Spectrometry (XPS)
[aka. Electron Spectroscopy for Chemical Analysis (ESCA)]
Olympus BH‐2 Fluorescence Microscope
Specialized Microscopy Fluorescence
• Commonly used in reflected light mode• Mercury vapor light source (100 watt)• Ultra‐violet and violet filters for monochromatic light• View visible wavelength light colors in eyepieces• Observe natural fluorescence in materials• Observe artificially induced fluorescent dyes (fluorochromes) in materials
Fluorescence MicroscopyAdhesion Promoter Dye/Resin Penetration into TPO
No Penetration
450 - 500 µm Penetration
100µm
100µm
Fluorescence MicroscopyBeverage Can/Aluminum End Seam
Can Sidewall
Aluminum End
Beverage
SealingCompound with Fluorescent Dye
JEOL JSM‐6480LV Scanning Electron Microscope (SEM)
Specimen Chamber
Monitors
Electron beam column
X-Ray Detector Specimen Chamber
Beam/Sample Interactions
JEOL
Image Formation
Movie presentation courtesy of:
OXFORD INSTRUMENTS
SEM/EDS Elemental MappingDry Dog Food Pellet
garnet
quartz
biotite orthoclase
anorthite
ilmenite
SEM/EDS Mineral Identification
JEOL JXA‐8200 Superprobe
Monitors
Electron beam column
EDS X-Ray Detector
Specimen Chamber
5 WDS X-Ray Spectrometers
NWA 176 Wavelength Dispersive X‐ray Maps
Magnesium Silicon
Oxygen
3.5”
2.5”
NWA 176 “Center” SEM Backscattered Electron Image
IronNickel
Sulfur
NWA 176 “Center” Wavelength Dispersive X‐ray Maps
Phosphorous
Smudge in Hair – Gunshot Residue (GSR) or Dirt?
We search for sub-10µm characteristic GSR particles which contain:lead (Pb), barium (Ba), antimony (Sb)
Hair Images by Transmitted Light Microscopy
50 µm
One Strand of the “Dirty” Hair Strands of Clean Hair
Smudge in Hair – Gunshot Residue (GSR) or Dirt?
BEI Image of Hair Tape Lift
WDS Maps – GSR!
Pb
Ba Sb
Cameca IMS 1280 Secondary Ion Mass Spectrometry (SIMS)
Ion Source and Specimen Chamber
Mass Analyzer
Detector
Primary Ion Beam
Secondary Ions,Atoms, ElectronsSecondary Ions,Atoms, Electrons
Secondary Ions, Atoms, Electrons
SIMS Sputtering Process
SIMS Technique
Mass Analyzer
SampleSample
Primary Ion Beam( O2
+ , O–, Ar+, Cs+, Ga+ )
Coating Craters in Aluminum Cans
SIMS Ion MapsSEM Images Corrosion Pit
SIMS Ion Maps
Pit #1 Pit #2
Calcium
Boron
Iron
SIMS Ion Images of Beryllium‐Containing Particles
Renishaw inVia Raman Microscope
Raman mapping can be performed on:• Tablets (distribution of active ingredients)• Inks and pigments (document forgery, art
conservation)• Electronics (silicon integrity)• Rocks (distribution of minerals)• And more!Spatial resolution from several mm down to ~ 1 µm
Raman Spectroscopy
inelastically scattered light (Raman)(different wavelength)
laser light(incident light)
scattered light (Rayleigh)
Raman spectroscopy measures inelastically scattered light; the difference in wavelength between the inelastic light and incident light corresponds to a vibrational mode
Information about molecular groups and crystalline structures
Raman map collected using 50X magnification, 785nm excitation laser
Example: Calcium carbonate and sucrose distribution from a supplement tablet
Calcium carbonate
Sucrose Overlay
LM Image
Physical Electronics Quantum 2000 Scanning ESCA Microprobe
Sample Chamber
XPS — InstrumentationSchematic of XPS Analysis using Focused, Monochromatic X-rays; a Hemispherical Electron Analyzer; and a Multichannel Detector
Electron Gun
Aluminum Anode
Ellipsoidal Monochromator
Sample
Electron Beam
Hemispherical Analyzer
Multichannel Detector
X-ray BeamPhotoelectrons
Hardware &Software
XPS Spectrum
Carbon Centroid Map and Basis Areas XPS LLS Fit Basis Spectra
XPS LLS Fit Maps LLS Fit Map Overlay
XPS — Chemical State Mapping
Summary• The “Where’s Waldo Dilemma” in microscopy can be solved
• Multiple instrumentation and methods can be employed to produce distribution maps of materials, i.e., if it’s there we’ll find it!
(OK, most of the time!)
• The choice of instrumentation/method is sample dependent and requires careful strategic planning with the client to provide the most useful results.
Thank you for joining us today.
Questions?
Wayne D. NiemeyerSenior Research Scientist
[email protected] (630) 887-7100