243 17
Gold Layer, Aluminum Layer, Nickel Layer
Detector crystals typically have conductive layers on their
front face to ensure conductivity. These layers can be con-
structed by depositing various different metals on the sur-
face. The absorption profiles of these layers will decrease the
efficiency of the detector. The layer thicknesses are particu-
larly relevant for simulation; however, other uncertainties
usually exceed the effect of the conductive layer.
Dead Layer
The dead layer is an inactive or partially active layer of silicon
on the front face of the detector. The dead layer will absorb
some X-rays (particularly low energy X-rays) and produce
few to no electron–hole pairs. The result is a fraction of X-rays
which produce no signal or a smaller signal than their energy
would suggest. The result is twofold: The first effect is a dimin-
ishment of the number of low energy X-rays detected. The5 00010 00015 00020 00025 00030 00035 0000Counts5 600 5 700 5 800 5 900 6 000 6 100 6 200
Energy (eV)Mn 1Full heightMn
K-L3Mn
K-L2. Fig. 17.5 Estimating the full width at half-maximum peak width. This peak is approximately 139 eV FWHM which you can confirm with a ruler
WD: Working distance
DD: Detector distanceSide viewElectron
columnXXZY
YSampleElevationDetector snoutDD
WDElectron
columnTop view
looking downDetectorEle
columnDetectorEleDetectorAzimuth. Fig. 17.6 Definitions of elevation angle and azimuthal angle
17.1 · Getting Started With NIST DTSA-II