PMI training: questions to ask about XRF, OES and LIBS
Before comparing positive material identification (PMI) techniques, write down the material question you need to understand. A clearer question makes a training syllabus and an analyzer’s capability statement easier to read.
Start with the element question, not just the alloy name
A lesson that asks you to “identify the alloy” can leave several things unspecified: the material described, the element of interest and the evidence available. Put those details in your study notes before comparing equipment names.
Evident’s explanation of handheld XRF gives a useful example: carbon is not directly measured by handheld XRF, although some alloy grades can be identified using other constituents. A grade identification and a direct measurement of a particular element are therefore different claims.
If a classroom report shows an alloy name, ask which measured elements support that identification. Do not assume the name establishes a value for every constituent.
What do XRF, spark OES and LIBS mean?
Thermo Fisher’s comparison introduces three different ways to obtain elemental information. Use these short definitions to recognize the technique discussed in a lesson.
- X-ray fluorescence (XRF) examines characteristic fluorescent X-rays emitted by the sample.
- Spark optical emission spectroscopy (spark OES) uses a spark to excite the sample and examines the emitted light.
- Laser-induced breakdown spectroscopy (LIBS) uses a laser to create a plasma and examines its emitted light.
Try rewriting an unclear study request
Use this fictional classroom prompt: “Sample A is described as stainless steel. The report gives an alloy name. Does that answer the carbon question?” No analyzer model or measurement results have been supplied.
Write a fuller question: “Does the named analyzer directly measure the element in this lesson’s question, and which supplied document supports that capability?” This asks for missing evidence, without choosing an instrument or accepting a component.
Now complete the three lines below using only information supplied in your lesson. Leave an unknown blank and write where you would look for it.
- Material and reference: what material is described, and which lesson document or specification identifies the question?
- Element: what constituent or distinction are you investigating?
- Evidence: what is the exact analyzer model, and which capability statement or example result addresses that element?
Match PMI training to the work you need to understand
NDT Academy’s PMI course covers alloy chemistry, XRF, OES and LIBS, method selection and traceable reporting. Use the public syllabus to locate the topics that help you complete your study question.
A technique’s name alone does not establish the capability of every analyzer that uses it. Compare the course with your employer’s actual instrument, procedure and training plan. Formal instruction does not by itself qualify you to operate every analyzer; equipment-specific practical skills and applicable safety requirements remain part of your employer’s preparation for the work.
Sources and further reading
Sources checked on September 22, 2026. Follow the current requirements from your employer or certification body when planning qualification or an examination.