working principle

Energy dispersive XRF (ED-XRF) directly receives characteristic X-rays generated by sample excitation through semiconductor detectors, converts them into electrical signals according to energy, and forms elemental characteristic spectral lines after processing by electronic circuits. Its core lies in the ability to distinguish different elements through detector energy resolution without the need for a splitting crystal, achieving synchronized detection of multiple elements.

Wavelength dispersive XRF (WD-XRF) utilizes crystal diffraction effects to disperse characteristic X-rays into different spectral lines according to wavelength. After the sample is excited, the dispersive crystal separates X-rays of different wavelengths, and the detector receives signals of specific wavelengths, combined with Bragg's law to achieve elemental analysis. The core lies in the precise screening of wavelengths by the spectroscopic crystal, ensuring high-resolution detection.

Advantage boundary

Resolution and sensitivity

WD-XRF adopts a spectroscopic crystal, which can effectively separate the characteristic spectral lines of adjacent elements with higher resolution, especially suitable for trace element analysis (detection limit up to μ g/g level). The resolution of ED-XRF is relatively low, but it performs better in the high-energy photon range, and the detection limit under light substrate conditions can reach the level of 10~10 ² μ g/g.

Analysis speed and operational convenience

ED-XRF does not require the replacement of spectral crystals and can simultaneously detect all elements. It has a fast analysis speed (completing multi-element determination in 60-100 seconds), easy operation, and is suitable for rapid screening on production lines. WD-XRF requires crystal selection based on elements, and single element analysis takes a long time (2-5 minutes), but a multi-channel analyzer can shorten the detection time for multiple elements.

Sample adaptability

ED-XRF has no special requirements for sample shape and can directly analyze solids, powders, and liquids, making it suitable for irregular sample detection. WD-XRF requires a smooth sample surface (such as solid grinding, powder pressing) to ensure detection accuracy, but the sample preparation equipment is easy to obtain and the sample preparation process is standardized.

Equipment cost and maintenance

ED-XRF has a simple structure, low power (<100W), no need for high-power cooling systems, low equipment costs (40000 to 150000), and easy maintenance. WD-XRF is equipped with high-power X-ray tubes (1-4kW) and precision beam splitting systems, with high equipment costs (100000-400000), but long service life (>10 years) and better long-term stability.

Application scenarios

ED-XRF: Suitable for industrial quality inspection, environmental monitoring and other scenarios that require rapid testing, such as RoHS compliance verification of plastic products and online monitoring of ore grade.

WD-XRF: Suitable for high-precision analysis scenarios such as scientific research and geological exploration, such as soil heavy metal content determination and mineral composition analysis.