Bayarjargal - Abt. Kristallographie - Goethe-Universität
Bayarjargal - Abt. Kristallographie - Goethe-Universität
Bayarjargal - Abt. Kristallographie - Goethe-Universität
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Recent developments of the laser-heating<br />
facility in Frankfurt and at Petra-III<br />
Lkhamsuren <strong>Bayarjargal</strong><br />
Institut für Geowissenschaften, <strong>Abt</strong>. <strong>Kristallographie</strong>:<br />
<strong>Goethe</strong>-<strong>Universität</strong> Frankfurt a. M., Germany
Contents<br />
Laser heating facility in Frankfurt<br />
•CO 2 laser heating set-up<br />
•Pressure measurement<br />
•Temperature measurement<br />
•Problems of temperature measurement<br />
•Raman measurement<br />
Sample preparation<br />
•Laser drilling<br />
•Gas loading<br />
Laser-heating facility at Petra-III<br />
Outlook
The CO 2-laser -laser heating system in Frankfurt
The CO 2-laser -laser heating system in Frankfurt
The CO 2-laser -laser heating system in Frankfurt
Pressure determination (ruby fluorescence)<br />
λ<br />
The mobile spectrometer for pressure measurement. A green laser (532<br />
nm, 100 mW, cw) and mini spectrometer (HR4000, Ocean optics) are used<br />
for the measurement of ruby fluorescence signals. (H. Ahsbahs)<br />
[MX78] Mao, H. K., Bell, P. M., Shaner, J. W., Steinberg, D. J. J. appl. Phys. 49, 3276−3283 (1978)<br />
[MX86] H.K.Mao,J.Xu,andP.M.Bell,J.Geophys.Res.91,4673,1986.
Planck’s law<br />
I = ε<br />
2<br />
2π<br />
hc<br />
5<br />
λ<br />
1<br />
hc / λ kT<br />
e<br />
Temperature determination<br />
The Wien radiation law:<br />
For low temperatures, where hc/λkT >> ln (1),<br />
the Wien approximation can be used.<br />
2<br />
k ⎛ 2π<br />
hc ⎞ 1 1<br />
Wien = ln 5<br />
hc ⎜<br />
= −<br />
Iλ<br />
⎟<br />
⎝ ⎠ T λ<br />
Sliding two-color pyrometry<br />
T ( λ ) =<br />
( 1/<br />
λ ) − ( 1/(<br />
λ + δ ))<br />
Wien(<br />
λ ) − Wien(<br />
λ + δ )<br />
−<br />
1<br />
k<br />
hc<br />
ln ε<br />
Benedetti, L.R., Loubeyre, P., High Press. Res. 24, 423–445 (2004)<br />
h: the Planck’s constant<br />
c: the speed of light<br />
k: the Boltzmann’s constant<br />
λ: the wavelength of light<br />
T: the temperature<br />
ε: the emissivity
The CO 2-laser -laser heating system in Frankfurt<br />
Program for temperature<br />
determination from the<br />
thermal radiant emission
Problems: the emissivity and the chromatic aberration<br />
2<br />
2π<br />
hc 1<br />
= ε 5 hc / kT<br />
λ e<br />
I λ<br />
ε: The wavelength dependence of the emissivity<br />
is unknown for most crystals<br />
Normal spectral emissivities for liquid and solid iron at<br />
melting point. (1808 K)<br />
H. Watanabe, et al. International Journal of Thermophysics, Vol. 24, No. 2, March 2003<br />
E. Schultz et al. High Pressure Research Vol. 25, No. 1, March 2005, 71–83<br />
−<br />
1<br />
Schwarzfeld objective
Problems: Pressure and temperature distribution<br />
in laser heated DAC<br />
Width defined by the entrance slit of spectrograph<br />
Height defined by pixel size and binning<br />
Laser-heated diamond–anvil cell geometry.<br />
Image of hot area<br />
Temperature distribution in the diamond–anvil cell<br />
(10GPa) with a) coesite sample and solid argon, with a<br />
total heating power W=19 W; b) corresponding thermal<br />
A. Dewaele, et al.REVIEW OF SCIENTIFIC INSTRUMENTS<br />
pressure<br />
VOLUME<br />
distribution.<br />
69, NUMBER 6 JUNE 1998
Problems: Temperature determination for pulsed<br />
laser heating<br />
Shape of our laser pulse measured with a photodetector<br />
~solid line with filled points! and the corresponding<br />
calculated temperature of the stainless steel.<br />
CO 2 laser heating<br />
S. Rekhi, et al. REVIEW OF SCIENTIFIC INSTRUMENTS VOLUME 74, NUMBER 8 AUGUST 2003
Micro-Raman spectrometer (Renishaw)<br />
50 mW, 633 nm HeNe-Laser<br />
(200 mW, 532 nm Nd:YAG Laser)<br />
AG Prof A. Woodland<br />
Raman measurement<br />
PbCO 3 in NaCl at 6 GPa in DAC
Contents<br />
Laser heating facility in Frankfurt<br />
•CO 2 laser heating set-up<br />
•Pressure measurement<br />
•Temperature measurement<br />
•Problems of temperature measurement<br />
•Raman measurement<br />
Sample preparation<br />
•Laser drilling<br />
•Gas loading<br />
Laser-heating facility in Petra III<br />
Outlook
Laser drilling - overview (after R. Boehler)
Spark erosion machine<br />
(H. Ahsbahs)<br />
Gasket<br />
Gasket materials: Steel, Tungsten and Rhenium<br />
The laser drilled hole
Gas loading (N2 , Ar, He, Ne)
Contents<br />
Laser heating facility in Frankfurt<br />
•CO 2 laser heating set-up<br />
•Pressure measurement<br />
•Temperature measurement<br />
•Problems of temperature measurement<br />
•Raman measurement<br />
Sample preparation<br />
•Laser drilling<br />
•Gas loading<br />
Laser-heating facility at Petra-III<br />
Outlook
The fiber laser heating system<br />
for ‚extreme conditions‘-station@PETRA-III.
The fiber laser heating system<br />
for ‚extreme conditions‘-station@PETRA-III.
The fiber laser heating system<br />
for ‚extreme conditions‘-station@PETRA-III.
Outlook.<br />
.<br />
Outlook<br />
• CO 2 and Yb:fiber laser system works for one-sided<br />
annealing and heating of transparent and not transparent<br />
samples<br />
• Sample preparation:<br />
Autumn 2008: First gas loading in DAC<br />
• CO 2 :<br />
Improvement of T- and Raman measurement<br />
• Petra III:<br />
June 2008: Alignment and first laser heating experiment<br />
December 2008: one-sided laser heating system with half automation<br />
Summer 2009: double-sided laser heating system with automation
Acknowledgement<br />
Dr. Alexandra Friedrich (Frankfurt University)<br />
Dr. Reinhard Boehler (MPI für Chemie, Mainz)<br />
Prof. Björn Winkler (Frankfurt University)<br />
Dr. Leonid Dubrovinsky (BGI Bayreuth)<br />
The workshop<br />
Financial support:<br />
BMBF projekt (05KS7RF1): Laserheizung für die 'extreme<br />
conditions'-Station an Petra-III .<br />
Deutsche Forschungsgemeinschaft SPP1236 (Wi1232/25-1)<br />
JWGU Frankfurt: Cooling system for the laser<br />
Christiane-Nüsslein-Volhard Stiftung
Thank you for your attention
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