SEM EDS

"Energy-dispersive X-ray spectroscopy (EDS, EDX, or XEDS)"

List of EDS manufacturers:

• • EDAX
  • Website]
  • Oxford Instruments
  • Website]
  • Noran Instruments (now Thermo Scientific)
  • Princeton Gamma-Tech (PGT, now Thermo Scientific)
  • Bruker
  • Website]
  • Evex (Kevex?)
  • "To enjoy this site you'll need to update your Flash Player. It's easy, painless and will take just a moment… "
  • haha never buying your products
  • Link Analytical
  • e2v Sirius

Typical systme:

• • Thin window (Be, C, B)
  • SiLi crystal
  • FET pre-amplifier
  • Vacuum
  • Cold finger
  • Pre-amplifier
  • Amplifier
  • MDA electronics (“multi channel analyzer”)

Detector

Styles

• Si-Li
• Silicon Drift Detector (SDD)

Si-Li

Operates at LN2 temps. If operated at room temp it will be destroyed

SDD

"SDD detectors operate at a few tens of degrees below zero"

Window

Styles [epmalab]:

• • Be foil
  • Supported window
  • Windowless

Be foil

"The most common EDS detector window has been made of Be foil ~7.6 um (0.3 mil) thick. It allows good transmission of X-rays above ~ 1 keV. It is strong enough to withstand venting to atmospheric pressure, and opaque to optical photons." [epmalab]

Supported window

"For transmission of light element X-rays (<1 keV), windows ~0.25 um thick of BN, SiN, diamond or polymer are used. They must use supporting grids to withstand pressure differentials; the grid (e.g., Si or Ni) takes up about 15% of the area, but thin enough that low energy X-rays pass through." [epmalab]

Ultra Thin Window (UTW)

made of:

• • Polymide ref]
  • "poly-vinyl formal (FORMVAR), butvar, parylene, kevlar, polypropylene, lexan or polyimide" ref]

Windowless

"no film, and there is a turret that allows swapping with a Be window. Difficult to use as oil or ice can coat the detector surface" [epmalab]

Gamma Spectacular

[1]]

How hard would it be to use this as EDS controller?

Model comparison

Image	Vendor	Model	Year	Features	List price	Ask price	Manual	Schem	SW	Notes
	EDAX	Genesis Spectrum	2006				Yes		Yes

References

• • [2]
  • Has a nice CAD drawing explaining the components of real EDS detectors
  • Beam MicroAnalysis-Geol_619-8.ppt