Silicon Drift Detectors (SDD) in Hitachi Elemental Analyzers

Determining the right XRF spectrometer for your elemental analysis interests can be a long process – the market is filled with different software features, staging options, chamber sizes, etc.  Even within the Hitachi High-Tech line of elemental analyzers (appropriately known as the ‘Hitachi EA Series’), different options can make one analyzer a more appropriate fit than others depending on your testing goals.

Vortex XRF Detection System

Hi-Resolution XRF Detector

One of the x-ray fluorescence options, or variables, that needs to be considered for most elemental analysis needs is the detector technology used.   The Hitachi EA Series offers four different analyzer configurations, from the ‘ultimate’ Hitachi EA6000VX to the more ‘entry model’ Hitachi EA1000A-III.  Three of the four feature a Hitachi manufactured Vortex Detector (VX in their names).  The Vortex Detector is a multi-cathode Silicon Semiconductor Detector but is more commonly referred to as a Silicon Drift Detector (SDD) and provides greater resolution, which can help improve results for many applications.

Associates of Eastern Applied Research ran some samples to show the difference in spectral resolution that a Vortex (SDD) Detector can offer over a more common Silicon Semiconductor Detector (SSD).  Analyzing two samples for RoHS testing interests, one plastic matrix and one metal, we compared the detailed spectrum for Pb from each detector technology.

Elemental Analyzer Detector Spectrums

It is clear that the Vortex SDD provides a more defined spectrum than the SSD technology.

The questions to ask are ‘why does this happen’ and ‘what is the benefit’?

Why a Vortex detector provides more defined spectrums:
The Vortex SDD’s feature large active areas (between 30mm2 and 80mm2) and are produced from high purity silicon with state of the art CMOS production.  They are able to provide excellent energy resolutions and high count rate capabilities – with a very short peaking time, a high count rate can be achieved.  Processing high count rates with very small loss in energy resolution and minimal peak shift is unique to these detectors – resulting in their high performance and longevity.  Learn more about the Vortex Detector.

What are the benefits of the Vortex Detector:
When the Hitachi XRF line is used for quantitative analysis of trace elements or qualitative analysis of unknowns (mining, geological testing, or a more detailed process control application) then the improved spectral peak differentiation provided by these detectors will result in the ability to achieve lower detection limits for a broad range of elements.

However, many of the Hitachi EA-Series spectrometers are used for RoHS testing.  So, when considering the benefits for this interest, basic RoHS interests can typically be achieved with the more common SSD technology – but the highly defined spectral peaks of a Vortex SDD can reduce the error of measurement while providing faster measurement times…resulting in increased confidence of results and greater throughput.

The detector technology in an XRF spectrometer is really only one aspect of the decision process your organization will be making.  Contact associates of Eastern Applied Research to have a complete discussion of your testing goals and the benefits that each Hitachi elemental analyzer can offer.

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