How to Use XRF Analyzer?

How to Use XRF Analyzer

X-ray fluorescence spectrometers are powerful tools for solving many different tasks related to the quantitative analysis of the chemical composition of materials.

A wide range of XRF spectrometers is currently available on the market, and along with benchtop spectrometers for laboratories, portable handheld XRF analyzers are becoming increasingly popular due to their high autonomy.

handheld XRF

As a rule, handheld XRF analyzers are extremely easy to use, and have an intuitive interface to minimize the need for operator training. The method of X-ray fluorescence analysis practically does not require sample preparation before measurements. In the case of solid samples, it is enough to simply check that the surface is sufficiently clean and clean it if necessary.

However, it should be noted that a file should be used for cleaning, and it is different for different types of samples (for example, for aluminum alloys and steels). In the case of loose samples, the test sample should be well crushed and mixed to ensure sufficient homogeneity. Modern XRF analyzers usually provide high measurement stability regardless of external conditions such as temperature and atmospheric pressure, and therefore allow research in the field.

However, being a high-tech tool, they still require proper handling. The instrument should be checked periodically on a calibration sample, which is usually supplied with the purchase of the instrument. Any even minor damage to important parts of the spectrometer can lead, if not to its failure, then at least to distortion of the measurements.

The most vulnerable part of the XRF spectrometer is the detector; as a rule, it is protected by a replaceable protective film. Please note that films come in different thicknesses and it is important to use the type of film specified in the instructions for the device, since using a film with a thickness different from that with which the calibration was carried out will lead to distortion of the measurement results.

It is strongly not recommended to take measurements without film, because not only will you get incorrect results, but it will be expensive to replace the detector if it is damaged.

When carrying out measurements, it is necessary to make sure that the calibration of the instrument is appropriate for the task. XRF analyzers are calibrated for a specific set of tasks and usually have different modes of operation for different tasks.

So, for example, you should not rely on accurate results of the analysis of precious metals with a device calibrated for alloys. Such a measurement can only carry qualitative information about the presence of a particular element in the sample, but the calculated concentrations may be far from the real ones.

To obtain accurate measurement results, do not neglect the procedures described in the instructions before starting measurements, as a rule, XRF analyzers need several minutes of warm-up to reach a stable operating mode, during which the results may be inaccurate.

Fields of application

Also, do not forget to periodically change the protective film to a clean one, especially when measuring samples with a high concentration of light elements, in particular aluminum, or when examining loose samples, since the particles remaining on the film from previously measured samples will be detected during new measurements.

When directly analyzing the spectrum of a sample, press the nose of the analyzer firmly against the sample so that there is no air gap between them. You can always adjust the spectrum acquisition time depending on the task at hand. The time required for the measurement depends on many parameters, in particular the workload of the spectrometer, the required accuracy, and the elements present in the sample.

As a rule, a few seconds are enough for express analysis, or determination of the grade of an alloy, while an accurate measurement of the concentration of a certain element in a sample requires a longer measurement time, reaching several minutes.

It is very important not to neglect safety precautions when taking measurements. In XRF spectrometers, as follows from the name of the method, an X-ray beam is used to excite the characteristic spectrum, which is ionizing and dangerous to humans. The body of the XRF analyzer is well shielded, this is always controlled by strict radiation control of each device to ensure the safety of the operator making the measurement.

However, it should be understood that the spectrometer window still remains unshielded, therefore, during measurements, in no case point the spectrometer at yourself or others, and do not hold the test sample in your hands. Despite the fact that, as a rule, the current in X-ray tubes used in XRF analyzers, and, consequently, the intensity of X-ray radiation, is quite small, regular exposure to radiation, even in small doses, is harmful to human health.

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