Scanning Electron Microscopy and X-Ray Microanalysis

214

16

Sn

E 0 = 20 keV

Au

E 0 = 20 keV

SnL

(^3) -M
4,5
escape
SnL
(^2) -M
(^4) escape
Au
M
(^5) -N
6,7
escape
Au
M
(^4) -N
(^6) escape
Photon energy (keV)
Photon energy (keV)
Co
unts
Counts
Au_20kV10nA50s
Sn_20kV10nA50s
16 000
14 000
12 000
10 000
8 000
6 000
4 000
2 000
0
12 000
10 000
8 000
6 000
4 000
2 000
0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
Au
N4-N6+5-N6
Au
M4-N2+5-N3
Au
M2-N1+3-N4+3-N5
Au
M3-N1
C K
-L2+3Sn M4-N2+5-N3
Sn M3-N1Sn M2-N1
Sn M3-N5
Sn M2-N4 Sn L3-M1Sn L2-M1
Sn L2-M4
Sn L3-M4+5
Sn L1-M2
Sn L1-M3Sn L3-N5
Sn L2-N4
Sn L1-N2+3
Sn esc
Au
M4-N6
Au
M5-N6+7
Au
M3-
O4+5
Au
M2-N4

. Fig. 16.5 Si-escape peaks observed with an SDD-EDS for Sn and Au (E 0 = 20 keV)

EDS black box

Artifacts: coincidence losses and coincidence peaks

Input:

X-ray photons

Output:

an estimate of

photon energy

Photon energy

Number of photons

t

Coincidence count

Photon #1

Photon #2

A coincidence rejection function

operates to rejectincorrect

measurements that result from

two different photons entering the

EDS detector at nearly the same

time and registering as one bad

count.

. Fig. 16.6 EDS “black box” rep-
resentation of photon coincidence

Chapter 16 · Energy Dispersive X-ray Spectrometry: Physical Principles and User-Selected Parameters