Portable double-sided pulsed laser heating system for time-resolved geoscience and materials science applications

Abstract

A portable double-sided pulsed laser heating system for diamond anvil cells has been developed that is able to stably produce laser pulses as short as a few microseconds with repetition frequencies up to 100 kHz. In situ temperature determination is possible by collecting and fitting the thermal radiation spectrum for a specific wavelength range (particularly, between 650 nm and 850 nm) to the Planck radiation function. Surface temperature information can also be time-resolved by using a gated detector that is synchronized with the laser pulse modulation and space-resolved with the implementation of a multi-point thermal radiation collection technique. The system can be easily coupled with equipment at synchrotron facilities, particularly for nuclear resonance spectroscopy experiments. Examples of applications include investigations of high-pressure high-temperature behavior of iron oxides, both in house and at the European Synchrotron Radiation Facility using the synchrotron Mössbauer source and nuclear inelastic scattering.

Novel Rhenium Carbides at 200 GPa

“…One more carbide, ReC 2 , with the orthorhombic structure found in Experiment #1 (Figure c, Supporting Information, Table S2, S7, Figure S4c) has the lattice parameters a = 3.3367(10) Å, b = 4.3155(16) Å, c = 5.6220(13) Å, and V = 80.95(4) Å 3 at 180(7) GPa, and a space group Fmmm (#69). Remarkably, the same orthorhombic phase [ a = 3.2880(9) Å, b = 4.2088(9) Å, c = 5.5645(8) Å, and V = 77.00(3) Å 3 ] was found in Experiment #2, in which iron oxide (FeO) in a Ne pressure medium was compressed to 219(5) GPa and pulsed‐laser heated up to 2500 ± 300 K . The relatively large beam (of about 25 µm at FWHM) irradiated the Re gasket used in Experiment #2 and ReC 2 was found at the border of the pressure chamber.…”

“…At pressures above ≈ 150 GPa, a pressure chamber's diameter (made, as a rule, of Re) is usually smaller than 50 µm, and in dsDACs above 300 GPa it is less than 10 µm. Meanwhile, the size of a laser beam in typical laser heating (LH) setups used in DAC experiments varies from 15 to 50 µm at FWHM , . As a result, irradiation of, at least the edge of a Re‐gasket, by the laser beam during laser heating becomes unavoidable and may lead to a chemical reaction between Re and carbon of the diamond anvils.…”

Comparative study of the influence of pulsed and continuous wave laser heating on the mobilization of carbon and its chemical reaction with iron in a diamond anvil cell

“…In PL, heating temperatures were tracked along the pulse duration using time-resolved spectroradiometry, as described in Ref. 20, with a PI-MAX 4 detector. Reported temperature values refer to the highest temperature achieved, with an uncertainty of ±150 K arising from possible temperature gradients, heating instability, and inaccuracy of the gray body approximation.…”

Novel Fe hydrides and magnetism in the Fe-H system at high pressures

“…Two infrared fiber lasers operating at 1070 nm were focused down to  40 μm (full width at a half maximum) at the sample position. The surface temperature was measured by the standard spectroradiometry method employing an IsoPlane SCT 320 spectrometer with a PI-MAX®4 1024i ICCD camera from Princeton Instruments 54 . Typical collection times ranged from 30 minutes to 8 hours depending on pressure and the desired statistics.…”