IPG Photonics

About: IPG Photonics is a based out in . It is known for research contribution in the topics: Laser & Fiber laser. The organization has 903 authors who have published 1241 publications receiving 63339 citations.

High brightness picosecond all-fiber generation in 525-1800nm range with picosecond Yb pumping.

Abstract: Pumping of highly-nonlinear microstructured fibers with zero-dispersion around the pump wavelength of a 50kW peak-power picosecond Yb-fiber laser allowed extensive polychromatic picosecond operation down to 525nm in all-fibre format. Spectral power densities over 1mW/nm and potential of further pulse compression to femtoseconds is demonstrated.

Structural changes in liquid Fe at high pressures and high temperatures from Synchrotron X-ray Diffraction

Abstract: High-energy synchrotron X-ray diffraction measurements on liquid iron in the vicinity of the δ-γ-liquid triple point (to 2300 K and 5 GPa) reveal significant changes in the structure of the liquid upon increasing pressure and temperature. The second and third neighbor shells in the g(r) shift to shorter distances and develop new structure with increasing pressure. The results can be interpreted in terms of the liquid acquiring bcc-like local order which evolves to a mixture of bcc- and fcc-like local order as pressure and/or temperature are raised.

U-series Constraints on Intraplate Basaltic Magmatism

Abstract: Intraplate magmatism represents approximately one tenth of the flux of magma to the Earth’s surface (Sleep 1990). This type of magmatism has received considerable attention from petrologists and geochemists as it generally exhibits a wider range of chemical compositions than the more uniform mid-ocean ridge basalts. Hence, it is rather paradoxical that our understanding of intraplate magmatism is rather poor. In this chapter, we review the insights that have been gained from using U-series measurements (combined with other chemical and isotopic constraints) to better understand the sources and processes related to intraplate volcanism. Several unique constraints can be obtained from measurement of U-series disequilibria in basalts. First, U-series fractionation can tell us about the residual phases present during melting as small differences in partitioning behavior between the nuclides will induce distinct signatures. Second, as has been shown by the earlier work of Allegre and Condomines (1982), Th isotope ratios can be used to infer the Th/U ratio of the mantle source providing another useful probe for mapping mantle heterogeneities. Lastly, as detailed below, the time-dependence of U-series fractionation during melting and melt migration can place constraints on several rate-dependent parameters such as the melt production rate, and melt velocities. An important feature of hotspot magmatism is that in many cases, the timing of hotspot activity seems to be decoupled from the motion of the lithospheric plate. This observation, which has been the basis for proposing the existence of mantle plumes, suggests that magmas erupted at hotspots should reveal something about the nature of the deeper mantle. Understanding the processes of hotspot magmatism should also tell us about the nature of convective motion responsible for hotspots. In the following section, we first review some of the outstanding issues that need to be resolved to better understand intraplate magmatism. We then …

Determination of thorium and uranium isotope ratios in low-concentration geological materials using a fixed multi-collector-ICP-MS

Abstract: Techniques used for the measurement of thorium and uranium isotope ratios in low-concentration (<0.1 ppm) geological materials on a Nu Instruments® MC-ICP-MS are described. Using an Aridus® micro-concentric, desolvating nebuliser sample introduction system, the beam current in a Faraday collector is typically 1.0 nA ppm−1232Th (total system efficiency = 0.3%). The abundance sensitivity is less than 100 counts s−1 at 1 mass unit below a large peak with an intensity of 1 × 109 counts s−1, or <0.1 ppm. The Faraday–ion counting gain is stable over a day and the method can provide 230Th/232Th ratio measurements on ng quantities of total dissolved Th to a precision that is better than 1% (95% confidence level). This is comparable to results obtained by thermal ionisation mass spectrometry on samples that are typically 10 to 100 times larger. Results for our internal laboratory standards are presented together with our results for standards used in other laboratories to facilitate inter-laboratory comparison.