Reinhard Noll

Laser-induced breakdown spectroscopy - a versatile tool for process control

Laser-induced breakdown spectroscopy (LIBS) is able to rapidly analyze the constituents of materials without contact under atmospheric conditions. Hence this method is predestined to applications where processes have to be controlled for various compounds. Current research activities aim to improve the limits of detection of LIBS for multi-element analysis. The influence of the laser pulse structure on the emission of the laser-induced plasma is investigated. Using certified reference samples, LIBS is calibrated to perform concentration measurements of elements in an iron matrix. An overview of recent LIBS applications is given.

LIBS analyses for industrial applications : an overview of developments from 2014 to 2018

Measuring distances in the range between a few centimetres and a few metres are of special interest for automated industrial LIBS applications. They allow for a reliable optical access to measuring objects in a process line under harsh industrial environments. In that range a compromise can be found between the conflicting requirements with respect to the protection of the optics facing the measuring object on one side, and sufficiently high laser irradiance and high receiving solid angle of the measuring radiation on the other side. A concise overview about LIBS studies published in the last four years focusing on industrial applications or perspectives therefore is given. Recent RD (b) sorting of refractories; (c) identification of steel blooms in a rolling mill; (d) inverse production scenario for the recovery of valuable materials from end-of-life electronic equipment. For measuring distances of only a few centimetres the size of a LIBS instrument can be downscaled significantly allowing to set up handheld LIBS analysers. Whereas the precursors of such concepts were studied already more than fifteen years ago, quite recently a competitive market arose where various models of handheld LIBS systems are offered. Industrial application fields are mainly positive material identification of metals and sorting of light metal scraps for recycling purposes. A comparative synopsis of features of these LIBS systems will be presented and arising research themes in this context are outlined.

Multielemental analysis of low-alloyed steel by laser-induced breakdown spectrometry

Laser-induced breakdown spectrometry (LIBS) is a non-contact in-situ method for the chemical analysis of various materials. Our R&D activities concentrate on the improvement of the analytical features of LIBS for the quantitative multi- elemental analysis of low-alloyed steel grades. The analytical sensitivity for the crucial elements C, S, and P, but also for Mn, Si, Cr and Ni was enhanced significantly. The limit of detection achieved for these elements is below 10 (mu) g/g. For low alloyed steel, the analytical performance of LIBS has now achieved for most elements the level of conventional laboratory based methods such as spark-discharge optical emission spectrometry (SD-OES).

Quality assurance in the production of pipe fittings by automatic laser-based material identification

In plants of the chemical, nuclear and off-shore industry, application specific high-alloyed steels are used for pipe fittings. Mixing of different steel grades can lead to corrosion with severe consequential damages. Growing quality requirements and environmental responsibilities demand a 100% material control in the production of the pipe fittings. Therefore, LIFT, an automatic inspection machine, was developed to insure against any mix of material grades. LIFT is able to identify more than 30 different steel grades. The inspection method is based on Laser-Induced Breakdown Spectrometry (LIBS). An expert system, which can be easily trained and recalibrated, was developed for the data evaluation. The result of the material inspection is transferred to an external handling system via a PLC interface. The duration of the inspection process is 2 seconds. The graphical user interface was developed with respect to the requirements of an unskilled operator. The software is based on a realtime operating system and provides a safe and reliable operation. An interface for the remote maintenance by modem enables a fast operational support. Logged data are retrieved and evaluated. This is the basis for an adaptive improvement of the configuration of LIFT with respect to changing requirements in the production line. Within the first six months of routine operation, about 50000 pipe fittings were inspected.

Perspectives of Laser Spectroscopic Methods for Security, Industrial and Biochemical Applications

An overview of applications of laser-spectroscopy for detection of explosives, food safety and elemental analysis of moving objects for raw material processing and recycling tasks is given. The presentation focuses on Raman, fluorescence and LIBS-spectroscopy. Article not available.

Online multi-elemental analysis using laser-induced breakdown Spectrometry (LIBS) – Research fields, industrial applications and future perspectives

Extended knowledge of the interaction mechanisms between pulsed laser radiation and matter as well as methodological and technological progress achieved over the last years have opened new R&D fields and industrial applications for laser-induced breakdown spectrometry (LIBS). This paper gives an overview of current LIBS R&D activities focused on industrial applications ranging from quality assurance and process control tasks in steel industry, via speciation analysis by combination of chromatographic separation techniques with LIBS to the fast identification of scrap pieces for material specific recycling in high-throughput sorting lines. The dual use of laser radiation as a contactless processing tool and an analyzing tool to determine the chemical composition of samples without the need of any mechanical or chemical preparation is a promising perspective for LIBS to simplify and to shorten existing process chains.Extended knowledge of the interaction mechanisms between pulsed laser radiation and matter as well as methodological and technological progress achieved over the last years have opened new R&D fields and industrial applications for laser-induced breakdown spectrometry (LIBS). This paper gives an overview of current LIBS R&D activities focused on industrial applications ranging from quality assurance and process control tasks in steel industry, via speciation analysis by combination of chromatographic separation techniques with LIBS to the fast identification of scrap pieces for material specific recycling in high-throughput sorting lines. The dual use of laser radiation as a contactless processing tool and an analyzing tool to determine the chemical composition of samples without the need of any mechanical or chemical preparation is a promising perspective for LIBS to simplify and to shorten existing process chains.