high pressure J. Synchrotron Rad. (2009). 16, 737–741 doi:10.1107/S0909049509039065 737 Journal of Synchrotron Radiation ISSN 0909-0495 Received 9 June 2009 Accepted 25 September 2009 # 2009 International Union of Crystallography Printed in Singapore – all rights reserved Portable laser-heating system for diamond anvil cells L. Dubrovinsky, a * K. Glazyrin, a C. McCammon, a O. Narygina, a E. Greenberg, a S. U ¨ belhack, a A. I. Chumakov, b S. Pascarelli, b V. Prakapenka, c J. Bock d and N. Dubrovinskaia e a Bayerisches Geoinstitut, Universita ¨t Bayreuth, Bayreuth, Germany, b European Synchrotron Radiation Facility, Grenoble, France, c GeoCARS, University of Chicago, USA, d Precitek KG, Germany, and e Universita ¨t Heidelberg, Heidelberg, Germany. E-mail: leonid.dubrovinsky@uni-bayreuth.de The diamond anvil cell (DAC) technique coupled with laser heating has become the most successful method for studying materials in the multimegabar pressure range at high temperatures. However, so far all DAC laser-heating systems have been stationary: they are linked either to certain equipment or to a beamline. Here, a portable laser-heating system for DACs has been developed which can be moved between various analytical facilities, including transfer from in-house to a synchrotron or between synchrotron beamlines. Application of the system is demonstrated in an example of nuclear inelastic scattering measurements of ferropericlase (Mg 0.88 Fe 0.12 )O and h.c.p.-Fe 0.9 Ni 0.1 alloy, and X-ray absorption near-edge spectroscopy of (Mg 0.85 Fe 0.15 )SiO 3 majorite at high pressures and temperatures. Our results indicate that sound velocities of h.c.p.-Fe 0.9 Ni 0.1 at pressures up to 50 GPa and high temperatures do not follow a linear relation with density. Keywords: laser heating; diamond anvil cells; portable system; NIS; XANES. 1. Introduction The diamond anvil cell (DAC) technique initiated in the late 1950s provides opportunities for high-pressure researchers with Mo ¨ ssbauer, infrared and Raman spectroscopy, resistivity measurements, X-ray diffraction and inelastic scattering (Eremets, 1996). During the last few decades the DAC tech- nique has become the most successful method of pressure generation capable of working in the multimegabar pressure range (Duffy, 2005; Dubrovinsky et al. , 2007; Dewaele et al. , 2007). However, there are still a number of problems related to high-temperature experiments in DACs. There are two major methods of heating in DACs: laser and electrical (Eremets, 1996; Dubrovinskaia & Dubrovinsky, 2005). Elec- trical heating is very efficient at temperatures below  1000 K at pressures over 250 GPa, but laser-heating experiments become very demanding if higher temperatures are required (Dubrovinskaia & Dubrovinsky, 2005). Laser-heating techni- ques cover a wide P–T field: P > 200 GPa, T = 1300–5000 K (Hirose, 2006; Dewaele et al. , 2007; Dubrovinsky et al. , 2007). The sample preparation for laser-heating experiments is relatively easy and there is practically no risk to the diamonds owing to heating. There are numerous DAC laser-heating facilities in geo-, material-, physics- and chemistry-oriented laboratories (including the Bavarian Geoinstitute), and there are a number of examples of successful coupling of an in situ laser-heating system with synchrotron radiation facilities, including specialized beamlines at the third-generation synchrotrons: European Synchrotron Radiation Facility (ESRF), Advanced Photon Source (APS) and SPring-8 (Shen et al., 2001; Hirose, 2006; Schultz et al., 2005; Prakapenka et al., 2008). However, so far all existing DAC laser-heating systems are stationary: they are linked either to certain equipment (an optical or Raman spectrometer, for example) or to a beamline. Studies of various physical properties and chemical reactions at high pressures and temperatures in DACs require mobility of the laser-heating system; for example, the ability to move laser-heating equipment (preferably together with the same DAC, at the same pressure) between different analytical facilities, including transfer from in-house to a synchrotron or between synchrotron beamlines. Here we report on the design, mode of operation and some examples of application of a portable laser-heating system for DACs. 2. Design of a portable laser-heating system for DACs The system consists of two major components: the source of laser light and the universal laser-heating head (UniHead) (Figs. 1 and 2). As a laser source we tested two SPI Lasers UK models, a G3 (30 W fibre-coupled pulse laser, weight 9 kg, excitation wavelength 1064 nm) and a SPI100 modulated high- power fibre laser (100 W, weight 40 kg, excitation wavelength