Why and how often should the protective windows in handheld analyzers be replaced

The protective windows are placed directly on the measurement window of the XRF analyzer, between the measured sample and the internal components of the spectrometer: the detector and the XRF tube. They are an integral component of any XRF analyzer, and if regular replacement of the protective window is not provided, the reliability and accuracy of the results obtained by the XRF analyzer cannot be guaranteed.

The protective windows are intended to protect important internal components of a portable XRF analyzer, primarily the detector, because if it is damaged it will be very expensive to repair. In addition to possible damage to the internal components of the spectrometer, the main role of the window is to protect the detector from dust or sample particles, since they will scatter the X-rays falling on the detector, distorting the spectrum and, therefore, the measurement results.

As already mentioned, it is important to keep the window on the instrument clean, because being directly between the sample and the detector, the window affects the fluorescence line intensities in the spectrum, and therefore the measurement results. Therefore, it is necessary to change the protective window periodically, as dust and particles from previous samples collect on it over time, which will affect the accuracy of future measurements. It is recommended to change the window before each measurement series, although the necessity of changing it depends on the type of samples being measured. After measuring aluminum alloys, the window should always be changed, because aluminum particles left on the film will cause a significant error in the measured aluminum concentration of the following samples, while for alloys containing mainly heavy elements, the film can be changed less often. In any case, if you have doubts about the reliability of the measurement results, the first thing to do is to replace the protection window.

Protection windows come in different types, and you should always use the window recommended by the analyzer manufacturer. Using different windows from the ones that were used to calibrate the instrument will most likely cause errors in the results, because different types of protective windows have different thicknesses and materials, and therefore absorb X-rays in different ways. Thus, a thicker window will absorb more low-energy radiation, resulting in an underestimation of the concentration of light elements in the measurement.

Our ProSpector 2 and ProSpector 3 handheld analyzers use two types of protective windows: Ultralene (red) for samples with light elements and Kapton (yellow) for samples without light elements. The windows fit tightly into the nose of the analyzer and are designed so that they can be quickly and easily replaced. 

Under no circumstances do not perform measurements without a protective window, as it not only leads to errors due to different calibration and measurement conditions, but also greatly increases the risk of damaging or contaminating the detector, leading to expensive repairs.

Thus, protective windows are necessary to protect the vulnerable internal components of an XRF analyzer from dirt and contaminants, and the cleanliness and type of protective window require special attention from the operator in order to avoid errors in the results when analyzing with portable XRF spectrometers.

All protective windows for our handheld analyzers you may find here...