With over 1000 registrants and 2500 viewings, our webinar with Edax on the Past, present and future - the evolution of x-ray analysis was another highly popular event. Due to its popularity, we are publishing the Q&A from the event.

Once again, thank you to Jens Rafaelsen and Tara Nylese for such a fantastic webinar. It is available to watch on demand here.

Question 1:
In the past time around 20 years ago, I knew that the EDX technique can not quantify the C, H, N, O, B contents in steel. This is because of the X-ray background interference. However, I have seen in some reports they use EDX to quantify those elements in steel. Can the EDX technique today quantify those elements today? How? I have asked many users as well as a few authors they could not clarify these questions? Which company develops this scientific acceptable technique? How they calibrate it? Could you please explain?

Modern EDS systems are quite capable of identifying and quantifying light elements, typically down to Beryllium. Previously Beryllium windows were used to protect the detector and this prevented the transmission of low energy x-rays, but with polymer windows and now silicon nitride windows, response in the light element range is not much of an issue. The quantification of light elements is similar to quantification of other elements, but more subject to matrix correction factors, particularly absorption of the low energy x-rays in the sample. Also, due to the low energy of the x-rays involved, correct charge collection, electronic noise and pulse processing becomes very important. The models used for the quantification is typically based on corrections for elemental x-ray yield, backscatter loss, fluorescence and absorption in the material. All EDS manufacturers have their own quantification routines, but they are mostly based on published scientific papers and data.
For a standard less analysis, no calibration is needed besides the normal voltage-energy calibration of the detector system. While it is no problem to do standard less quantification on light elements, standards can be used to ensure maximum quality and reproducibility. For steel in particular the ANSI 316 standard is often used.

Question 2:
What is the importance of Be window of the detector of EDX instrument? How can I fix or replace the Be window if it is destroyed?

The window protects the EDS detector from contamination and maintains a vacuum within the detector module. While windowless detectors are available, one must be extremely careful to protect the detector from damage and contamination and be sure that it is at ambient temperature before venting to prevent condensation on the detector.
A Beryllium window is not user replaceable. Beryllium dust is toxic if inhaled, and even if a new window is available, a vacuum must still be established inside the detector module prior to sealing.

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