Measurements at laser materials processing machines: spectrum deconvolution including uncertainties and model selection

Laser materials processing of workpieces using ultra-short pulsed lasers can lead to unwanted X-ray emission. Their dose rate and spectral distribution have been precisely determined. The measurements were carried out using a thermoluminescence detector (TLD)-based spectrometer in which 30 TLD planes are arranged one behind the other, the first 10 layers made of polymethyl methacrylate, while the remaining 20 layers are interspaced by absorbers with, from the front to the back, increasing atomic charge and thickness. The penetration depth of the radiation into the spectrometer depends on its energy, so that the energy-resolved spectrum of the radiation can be calculated from the TLD dose values by means of mathematical methods (Bayesian deconvolution). The evaluation process also takes into account both the uncertainties of all input quantities and the possibility of adopting different models for the spectrum form. This allowed the resulting spectra to be associated with their realistic uncertainty. The measurements are traceable to the Système international d'unités (SI), i.e. the International System of Units. The results not only provide manufacturers and users of ultra-short pulsed lasers with important information on the design of the machines with regard to radiation protection, but were also included in the recently concluded legislative procedure in the field of radiation protection in Germany.

Laser Materials Fabrication and Joining

This laser special issue has brought together academic scientists, researchers and laser manufacturers for a share of their experiences on recent progress in laser science and technology in the fields of laser materials processing for manufacturing. The papers cover advances in laser materials fabrication and joining of emerging materials, their fabrication and application.

Laser marking features of metal products

Одним из востребованных методов лазерной обработки материалов является маркировка, позволяющая управлять лазерным излучением и обрабатывать различные материалы. В машиностроении такая маркировка применима при изготовлении и сборке изделий, в процессах автоматизации производства и логистики, при этом необходимо знать какие изменения происходят в структуре, составе и свойствах обрабатываемых материалов, какое влияние такая маркировка оказывает. Marking is one of the well-known methods of laser materials processing. This allows to control laser radiation and to treat various materials. In engineering, such marking is applicable in the manufacture and products assembly, in the processes of production automation and logistics. It is also necessary to know what changes occur in the structure, composition and properties of the processed materials and what kind of impact this marking renders.