(a) quantum efficiency or intrinsic efficiency, (b) energy resolution, (c) dead time and
maximum count rate, (d) dark noise, (e) dynamic range, and for certain applications
(f) spatial resolution. Some representative properties for different devices are summarized in Table 5.1.
Fig. 5.1 Left: Roentgen’s first X-ray image, supposedly of his wife’s hand. Right: the ATLAS
detector for the Large Hadron Collider (LHC). For scale, notice the man standing on platform
Table 5.1 Summary of most commonly used X-ray detectors for X-ray spectroscopy
Detector
ΔE/E (%)
(5.9 keV)
Typical
dead
time
Max count
rate (ph s
À1
per element)
Typical application
Gas ionization (i.e.,
ion chamber)
n.a.
~10
13
Beam line intensity monitor/
transmission XAS
Gas proportional
15
200 ns
~10
5
Mössbauer spectroscopy
Scintillation/NaI
(Tl)
40
250 ns
~2 Â 10
5
Fluorescence-detected XAS
Ge or Si
semiconductor
~3
~10 μs
~10
5
Fluorescence-detected
XAS/fluorescence elemental
analysis
Si drift detector
~3
~1 μs
~10
6
Fluorescence-detected
XAS/fluorescence elemental
analysis
Si strip detector
~3
~10
6
Position-sensitive RIXS
analysis
Avalanche photodiode (APD)
20
~1 ns
~10
8
Nuclear spectroscopies
Superconducting
tunnel junction
(STJ)
0.2
2
a
~20 μs
~5Â 10
4
Fluorescence-detected
XAS/soft X-ray fluorescence
Transition edge
sensor (TES)
<0.03
0.2
a
~1 ms
~10
3
Fluorescence-detected
XAS/soft X-ray fluorescence
a At ~500 eV
108
5 X-ray Detectors and Electronics