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Compres Laser Heating Activities
Technical
CO2 laser heating system at GSECARS
Component of ID-D upgrade (in progress)
Staff: Andy Campbell (50%, beginning July 1)
Scientific
Thermal pressure studies in laser heated DAC at 20-35 GPa (Kubo, Duffy, Shen)
Finite element modeling of thermal structures in laser-heated diamond cell (Kiefer and Duffy)
Ultrahigh P-T studies of crystal structures and phase relations
SiO2 (Shieh, Duffy, Shen)
MgSiO3 (Shim, Jeanloz, Duffy, Shen)
Outreach
Laser heating workshop held in March 2004 at APS
Laser-Heated Diamond Anvil Cell
Gasket
InsulationDiamond
Diamond
Sample
Al2O3
The Computational Grid
Finite element modeling (Flexpde) * Local refinement of mesh. * 1600-4000 nodes
Temperature (K/1000)
Insulation
Sample
Al2O3
Temperature Distribution in LHDAC
ΔTaxial (K)
Predicted Axial Temperature Drop
YAG:Ce
Ruby
Ar
Silicate + Pt
175m
X-ray fluorescence of YAG:Ce
Thermal emission from heated sample After multiple heating cycles
Laser heating of Pyrope (Mg3Al2Si3O12) Garnet at ~30 GPa
Precision (~3 micron) alignment of heating and x-ray spots achieved using fluorescent YAG:Ce crystals
10 15 20
?
?
Pt1
11
Pt2
00
Pt2
20
Pt3
11
Pt2
22
Pt3
31A
r422
Pt4
20
Pt4
00+
Ar4
20A
r331
Ar3
11
Ar2
20
Ar2
00
Ar1
11
MgO
422
MgO
420
MgO
331
MgO
400
MgO
222
MgO
311+
Ar2
22MgO
220
MgO
200
Inte
nsi
ty (
a.u
.)
2Theta / degrees (lambda=0.3311A)
before laser heating after laser heating
MgO
111
MgO+Pt (in argon)
~18GPa
20181614121086
Two Theta (
Inte
nsi
ty
Pt PtPt Pt Pt
Pt Pt
C
Pt
Pt
C
Pt
CCC
C
PtPt
PtPt
Pt
PtPtPt
Pt
Pt
C
CaCl2
PbO2
121(2) GPaT quench
117(2) GPaPreheat
129(4) GPa1860(400) K
123(3) GPa~1000(400) K
d (Å)3 2 1
Highest pressure experiments (stishovite starting material)
3500
3000
2500
2000
1500
1000
500
2500200015001000Depth (km)
3500
3000
2500
2000
1500
1000
500
Tem
pe
ratu
re (
K)
120100806040
Pressure (GPa)
Stishovite Cristobalite Silica glass
Murakami
CaCl2-type
Stishovite
Geotherm
Murakami
Inte
nsi
ty
20181614121086
Two Theta (2
P
P
P
P
C
CC C
ReRe
Pt
Pt
Ar Ar
Ar
Pt
D
77GPa, 300K
79GPa,1870K
101GPa,1500K
3 2d (Å)
2.5 1.5
85GPa,2200K
CaCl2PbO2
Cristobalite starting material
Conclusions:
CaCl2-phase of SiO2 stable to 131 GPa (2800 km depth in the mantle)
Complications:
Kinetic factors/ metastable phases
length, homogeneity of heating
starting material
stishovite (CaCl2-type)
glass
cristobalite
deviatoric stress, minor elements
low temperature (<1000 K) metastable phases also observed (Prakapenka et al., 2004)
Teter et al., 1998
MgSiO3 perovskite to 116 GPa (2550 km depth)
Shim et al., Science 2001; Geophys. Res. Lett., in press.
MgSiO3 perovskite at 140 GPa
Cmcm post-perovskite phase (Murakami et al., Science 2004) +
Modified MgSiO3 perovskite
(Shim et al., Science 2001)
Shim et al., Geophys. Res. Lett., in press
5 10 15
MgGeO3
Intensity / a.u.
2Theta / degrees
74 GPa, RT (Pv)
40 GPa, RT (Pv)
10 GPa, RT (En)
en
enen
en
en
enen
en en en?ar
ar
ar
steel
pt
steel
en?
pt
pv
?
?pv
arpvpv
pv
?
ptpv
ar
pt
steel
steelpv
pvpv
arpvpv
pv
pv
pvpv
pv
pv
pvpv
pv
arpv
arpv
pv + pt
steel pv?
arpt steel pvpv
pv
pvpv
pv
?
Enstatite -type
Perovskite -type
10 GPa
40 GPa
74 GPa
Laser Heating of
MgGeO3 at
HPCAT, April, 2004
Laser heating workshop
-- March 19-20, 2004 at the Advanced Photon Source
-- 41 participants including representation from Europe, Japan, and the US
-- Sponsored by COMPRES and GSECARS
-- Invited Speakers:
Heinz (Chicago) Yoo (LLNL) Kavner (UCLA)
Tschauner (UNLV) Shen (Chicago) Kiefer (NMSU)
Shim (MIT) Lin (CIW) Zha (Cornell)
Sturhahn (ANL) Meng (HPCAT) Clark (LBNL)
Sata (JAMSTEC) Dubrovinsky (Bayreuth)
-- Discussion Sessions:
What features are required in the next generation laser heating system at GSECARS?
What are the key technical issues for next-generation laser heating?
What community-wide efforts are needed to advance laser heating capabilities at synchrotrons?
-- Dissemination
Meeting presentations (PPT) posted at COMPRES website
Meeting summary document available for dissemination
