X-Ray Spectrometry and Spectrum Image Mapping at Output Count Rates Above 100 kHz with a Silicon Drift Detector on a Scanning Electron Microscope

Published

September 1, 2005

Author(s)

Dale E. Newbury

Abstract

A third generation silicon drift detector (SDD), a silicon multicathode detector (SMCD), was tested as an analytical x-ray spectrometer on a scanning electron microscope. The resolution, output count rate, and spectral quality were tested as a function of the detector time constant from 8 ms to 250 ns and over a range of deadtime (input count rate). The SDD-SMCD (50 mm² active area) produced a resolution of 134 eV with a time constant of 8 microseconds. The peak width was nearly independent of the input count rate (degradation 0.003 eV/percent deadtime at 8 ms). Useful output count rates of 200 kHz were achieved with a 500 ns time constant (188 eV resolution) and 350 kHz with a 250 ns time constant (217 eV resolution). X-ray spectrum imaging was achieved with a pixel dwell time as short as 10 ms (with 1.3 ms overhead) in which a 2048 channel (10 eV/channel) spectrum with 2-byte intensity range was recorded at each pixel. With a 300 kHz output count rate, a minor constituent below 0.05 mass fraction could be readily detected in the x-ray maps derived from the x-ray spectrum image.

Citation

Scanning

Volume

27

Issue

No. 5

Pub Type

Journals

Keywords

energy dispersive x-ray spectrometry, scanning electron microscope, silicon drift detector, x-ray mapping, x-ray microanalysis, x-ray spectrum imaging

Citation

Newbury, D. (2005), X-Ray Spectrometry and Spectrum Image Mapping at Output Count Rates Above 100 kHz with a Silicon Drift Detector on a Scanning Electron Microscope, Scanning (Accessed December 30, 2024)