Recent developments of the laser-heating facility in Frankfurt and at Petra-III

Lkhamsuren BayarjargalInstitut für Geowissenschaften, Abt. Kristallographie:Goethe-Universität Frankfurt a. M., Germany

ContentsContents

Laser heating facility in Frankfurt •CO2 laser heating set-up

•Pressure measurement•Temperature measurement •Problems of temperature measurement •Raman measurement

Sample preparation•Laser drilling•Gas loading

Laser-heating facility at Petra-III

Outlook

The COThe CO22-laser heating system in Frankfurt-laser heating system in Frankfurt

The COThe CO22-laser heating system in Frankfurt-laser heating system in Frankfurt

The COThe CO22-laser heating system in Frankfurt-laser heating system in Frankfurt

Pressure determination (ruby fluorescence)

The mobile spectrometer for pressure measurement. A green laser (532 nm, 100 mW, cw) and mini spectrometer (HR4000, Ocean optics) are used for the measurement of ruby fluorescence signals. (H. Ahsbahs)

λ

[MX78] Mao, H. K., Bell, P. M., Shaner, J. W., Steinberg, D. J. J. appl. Phys. 49, 3276−3283 (1978)

[MX86] H.K.Mao,J.Xu,andP.M.Bell,J.Geophys.Res.91,4673,1986.

112

/5

2

−= kThce

hcI λλπε

h: the Planck’s constantc: the speed of light

k: the Boltzmann’s constantλ: the wavelength of light

T: the temperatureε: the emissivity

Planck’s law

Temperature determination

The Wien radiation law:For low temperatures, where hc/λkT >> ln (1), the Wien approximation can be used.

Sliding two-color pyrometry

ελλ

π ln112ln 5

2

hck

TIhc

hckWien −=

=

)()())/(1()/1()(

δλλδλλλ

+−+−=

WienWienT

Benedetti, L.R., Loubeyre, P., High Press. Res. 24, 423–445 (2004)

Program for temperature determination from the

thermal radiant emission

The COThe CO22-laser heating system in Frankfurt-laser heating system in Frankfurt

Problems: the emissivity and the chromatic aberration

Normal spectral emissivities for liquid and solid iron at melting point. (1808 K)

H. Watanabe, et al. International Journal of Thermophysics, Vol. 24, No. 2, March 2003E. Schultz et al. High Pressure Research Vol. 25, No. 1, March 2005, 71–83

112

/5

2

−= kThce

hcI λλπε

ε: The wavelength dependence of the emissivity is unknown for most crystals

Schwarzfeld objective

Problems: Pressure and temperature distribution in laser heated DAC

Laser-heated diamond–anvil cell geometry.

A. Dewaele, et al.REVIEW OF SCIENTIFIC INSTRUMENTS VOLUME 69, NUMBER 6 JUNE 1998

Temperature distribution in the diamond–anvil cell (10GPa) with a) coesite sample and solid argon, with a total heating power W=19 W; b) corresponding thermal pressure distribution.

Width defined by the entrance slit of spectrograph

Height defined by pixel size and binning

Image of hot area

Problems: Temperature determination for pulsed laser heating

Shape of our laser pulse measured with a photodetector ~solid line with filled points! and the corresponding calculated temperature of the stainless steel.

S. Rekhi, et al. REVIEW OF SCIENTIFIC INSTRUMENTS VOLUME 74, NUMBER 8 AUGUST 2003

CO2 laser heating

Raman measurementRaman measurement

Micro-Raman spectrometer (Renishaw)50 mW, 633 nm HeNe-Laser(200 mW, 532 nm Nd:YAG Laser)

AG Prof A. Woodland

PbCO3 in NaCl at 6 GPa in DAC

ContentsContents

Laser heating facility in Frankfurt •CO2 laser heating set-up

•Pressure measurement•Temperature measurement •Problems of temperature measurement •Raman measurement

Sample preparation•Laser drilling•Gas loading

Laser-heating facility in Petra III

Outlook

Laser drilling - overview (after R. Boehler)Laser drilling - overview (after R. Boehler)

GasketGasket

Spark erosion machine (H. Ahsbahs)

Gasket materials: Steel, Tungsten and Rhenium

The laser drilled hole

Gas loadingGas loading (N2, Ar, He, Ne)

ContentsContents

Laser heating facility in Frankfurt •CO2 laser heating set-up

•Pressure measurement•Temperature measurement •Problems of temperature measurement •Raman measurement

Sample preparation•Laser drilling•Gas loading

Laser-heating facility at Petra-III

Outlook

The fiberThe fiber laser heating system laser heating systemfor ‚extreme conditions‘-station@PETRA-III.

The fiberThe fiber laser heating system laser heating systemfor ‚extreme conditions‘-station@PETRA-III.

The fiberThe fiber laser heating system laser heating systemfor ‚extreme conditions‘-station@PETRA-III.

.

• CO2 and Yb:fiber laser system works for one-sided annealing and heating of transparent and not transparent samples

• Sample preparation:Autumn 2008: First gas loading in DAC

• CO2: Improvement of T- and Raman measurement

• Petra III:June 2008: Alignment and first laser heating experimentDecember 2008: one-sided laser heating system with half automationSummer 2009: double-sided laser heating system with automation

OutlookOutlook.

Acknowledgement

Dr. Alexandra Friedrich (Frankfurt University)Dr. Reinhard Boehler (MPI für Chemie, Mainz)Prof. Björn Winkler (Frankfurt University)Dr. Leonid Dubrovinsky (BGI Bayreuth)The workshop

Financial support:BMBF projekt (05KS7RF1): Laserheizung für die 'extreme conditions'-Station an Petra-III . Deutsche Forschungsgemeinschaft SPP1236 (Wi1232/25-1)JWGU Frankfurt: Cooling system for the laserChristiane-Nüsslein-Volhard Stiftung

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