Archive for July, 2012

What’s the Benefit? Advancements in XRF Detector Technology

Xray Fluorescence SpectrumQSX Instruments Inc offers three x-ray fluorescence analyzers that feature the latest generation of detector technology – Silicon Drift Detection (SDD).  Two desktop models, the QSX-82D for RoHS testing and the QSX-295Tplus for precious metal assay, along with a soon to be released Handheld XRF (QSX-HH2) provide the newest technology.

Each of these systems has counterpart models that feature Si-PIN detector technology (or, they offer the option).  So, the question that many organizations considering XRF technology ask is “What are the benefits of SDD over Si-PIN?”.

Keep in mind that the detection system is one of the critical components in ED-XRF technology.  It collects the emitted energy that results from displaced electrons in the form of an x-ray before it can be processed by the software package.  The peak intensities of emitted x-rays are characteristic of the elements contained in the sample and provide information about the elements concentrations.  Detection systems are selected for an instrument based on their resolution, count rates, ability to filter out background, and the testing need the analyzer is being developed to solve.

Both Si-PIN and SDD operate without liquid nitrogen (LN2) and provide similar stability and life expectancies (typically 4-6 years with proper care).  The newer technology, SDD, provides two major benefits that are beneficial to certain application fields.

Major benefits of Silicon Drift Detectors:

Improved Resolutions: the typical resolution of Si-PIN systems is ~170-190eV while SDD will be around ~120-140eV.  The improvement from SDD results in better separation of elemental peaks which will potentially provide increased accuracies and elemental range (depending on the application).

Faster Measurement Times: as an example, for precious metal assay, the QSX-295T using Si-PIN technology will typically provide accuracies around +/- 0.5% to the absolute value of a sample with 30 or 60 second measurements.  The new QSX-295Tplus (with SDD) can offer +/- 0.25% to the absolute with only 10 to 20 second measurements.

So, is their a ‘negative’ to SDD systems?  While QSX Instruments offers the noted systems at a very competitive cost of acquisition, the price of XRF analyzers featuring SDD will always be greater than the counterpart Si-PIN models.  The cost/benefit analysis has to be considered on a per need basis.  As an example, companies using a handheld XRF for positive material identification will pay the difference because of the faster results SDD provides.  While organizations using the x-ray fluorescence for RoHS testing do not see enough of an improvement in detection limits or measurement times from SDD, so the Si-PIN technology may fit the budget better and meet the testing need.

The best system for your testing need is ultimately your organizations decision.  However, the QSX Instruments line can provide a variety of options and we provide the support required during your research and decision process…contact a Quickshot XRF sales associate for a discussion on the best fit for your application.