X-ray Dose Rate and Spectral Measurements during Ultrafast Laser Machining Using a Calibrated (High-Sensitivity) Novel X-ray Detector

Ultrashort pulse laser machining is subject to increase the processing speeds by scaling average power and pulse repetition rate, accompanied with higher dose rates of X-ray emission generated during laser–matter interaction. In particular, the X-ray energy range below 10 keV is rarely studied in a quantitative approach. We present measurements with a novel calibrated X-ray detector in the detection range of 2–20 keV and show the dependence of X-ray radiation dose rates and the spectral emissions for different laser parameters from frequently used metals, alloys, and ceramics for ultrafast laser machining. Our investigations include the dose rate dependence on various laser parameters available in ultrafast laser laboratories as well as on industrial laser systems. The measured X-ray dose rates for high repetition rate lasers with different materials definitely exceed the legal limitations in the absence of radiation shielding

Flexible Magnetic Reading/Writing System: Heat-assisted Magnetic Recording

Data storage is one of indispensable technical assets defined in a frame work of Industry 4.0. Among many data storage technologies, inherent magnetic data storage on surfaces of technical components is promising, especially when the components are employed in harsh environments. Comparing with other storage technologies like labels, RFID tags and engraving, the inherent magnetic storage is rewritable and resistant to weathering. High temperature and a high magnetic field, however, can degrade or even delete magnetically stored data. This limitation can be coped with using a medium with higher coercivity that can withstand external magnetic fields and high temperature. As a consequence of higher coercivity, a higher write field is required to magnetize the medium. A design of a flexible write head that is suitable for storage applications on surfaces of technical components, is restricted by head-medium interface criterions, and hence field strength generated from the write head cannot be arbitrary large. To solve this problem, a heat-assisted magnetic recording (HAMR) is proposed as a means to temporarily reduce coercivity of a medium during writing. A realization of a HAMR module and an experiment as well as its positive results are presented in this work