Nawrodt 05/2010
Thermal noise and material issues for ET
Ronny NawrodtMatt Abernathy, Nicola Beveridge, Alan Cumming, Liam Cunningham, Giles
Hammond, Daniel Heinert, Jim Hough, Iain Martin, Peter Murray, Stuart Reid, Sheila Rowan, Christian Schwarz, Paul Seidel, Marielle van Veggel
GWADW2010 Meeting, Kyoto 20/05/2010
Institut für Festkörperphysik, Friedrich-Schiller-Universität JenaSonderforschungsbereich Transregio 7 „Gravitationswellenastronomie“
Institute for Gravitational Research, University of GlasgowEinstein Telescope Design Study, WP2 „Suspension“
Nawrodt 05/2010
Overview
• Motivation
• Material Properties– thermal properties– mechanical properties
• Thermal Noise Issues for ET
• Summary
GWADW2010 Kyoto/Japan #2/54
Nawrodt 05/2010
Motivation
• ET will need a radical change in the materials in order to achieve the sensitivity goals:
– suspensions,– test mass materials,– coatings,– optical materials
• Additionally, going towards cryogenics temperatures will dramatically change material properties additional degree of freedom.
• The new material has to be compared to the best optical material currently available at room temperture!
GWADW2010 Kyoto/Japan #3/54
Nawrodt 05/2010
Material Properties – Thermal Conductivity in Crystals
GWADW2010 Kyoto/Japan
• typically 3 zones:
– higher temperatures: TC is limited by phonon-phonon scattering– lower temperatures: mean free path of phonons increases,
scattering at impurities becomes important
– high purity samples: at very low temperatures the sample geometry becomes important (scattering of phonons at the sample surface limitation of TC)
#4/54
Nawrodt 05/2010
Material Properties – Thermal conductivity of Silicon
experimental results (double-log scale!):
“recommended curve”(< 1014 cm-3 boron, approx.1 mg B in 1 t Si)
increasing impurity concentration (scatteringof phonons on impurities)
smaller structures + impurities(~ 1/L term)see Callaway 1961 or Casimir 1938
[Touloukian]
GWADW2010 Kyoto/Japan #5/54
Nawrodt 05/2010
• in high purity silicon the different silicon isotopes take the role as scatter centers (-> impurities)
• natural Si has 3 stable isotopes:– 92% Si-28– 5% Si-29– 3% Si-30
• they cause small local changes in the lattice due to their different atom masses effect is small
• however, concentration is very large compared to typical impurity concentrations (ppm range)
Material Properties – Thermal conductivity of Silicon
GWADW2010 Kyoto/Japan #6/54
Nawrodt 05/2010
• it is possible to enrich/purify silicon
• isotopic pure silicon shows a much larger thermal conductivity in the peak region compared to standard semiconductor grade silicon
• 99.8% Si-28:TC ~ 10x larger
• disadvantage:price ~ 1000 US$/gsemiconductor grade ~ 500 US$/kg
[Ruf et al., Solid State Comm. 115 (2000)]
Material Properties – Thermal conductivity of Silicon
GWADW2010 Kyoto/Japan #7/54
Nawrodt 05/2010
Mechanical Properties – Mechanical Loss of Materials
•
GWADW2010 Kyoto/Japan #8/54
Nawrodt 05/2010
Mechanical Properties – Surface loss
• sudden change of chemistry at the surface end of periodicity of crystal lattice remaining defect in perfect single crystals
• it was shown that the surface loss can be influenced by proper treatments (heating, passivation, etc.)
• however, most of these changes are not stable and the surface loss gets back to the initial level after hours
GWADW2010 Kyoto/Japan #9/54
Nawrodt 05/2010
Mechanical Properties – Impurities
• imperfection in crystals can change their states (moving, rotation, …)
• example: crystalline quartz (SiO2)
modelled as double well potential
GWADW2010 Kyoto/Japan
view along the c-axis
OSi
E
ener
gy
position
21
TkE
0Be
“Debye-peak”
thermally activated transition
#10/54
Nawrodt 05/2010
Mechanical Properties – Impurities in Silicon
• doping concentration is variable lowest possible value will used
• most serious impurity in Si is oxygen from the growing process (electronically not active nearly no support from
semiconductor industry!)• two growing processes:
from melt from solidCzochralski-process Floating-Zone-process
O-concentration: 1018 cm-3 O-concentration: 1014 cm-3
max. dia. in some years max. dia. in some years~ 45 … 50 cm ~ 30 … 35 cm
GWADW2010 Kyoto/Japan #11/54
Nawrodt 05/2010
Mechanical Properties – Phonon-Phonon-Interaction
• fundamental process in crystalline solids cannot be avoided• two mechanisms:
– high temperatures / high frequenciesdirect interaction of one phonon with another one
(Landau-Rumer-process)
– low temperatures / low frequencies
elastic mode (low frequency phonon) changes the lattice change of the equlibrium distribution of phonons
redistribution needs energy loss
(Akhiezer-process)
GWADW2010 Kyoto/Japan #12/54
Nawrodt 05/2010
Mechanical Properties – Mechanical loss in solids
GWADW2010 Kyoto/Japan
crystalline quartz silicon
impurities could be indentifiedto be alkaline ions from thegrowing process
origin of most of the peaks unclear(blue – oxygen in silicon)
#13/54
Nawrodt 05/2010
Mechanical Properties – Mechanical loss in solids
GWADW2010 Kyoto/Japan #14/54
Nawrodt 05/2010
Thermal Noise – Bulk Material
GWADW2010 Kyoto/Japan
• Thermo-elastic noise:
• Brownian thermal noise:
32222/5
222BITM
TE wfC1Tk4)T,f(S
[Liu, Thorne 2000])T,f(S'C)T,f(S ITMTE
2FTM
FTMTE
[Braginsky 1999]
)T,f(Yw
1f
Tk2)T,f(S substrate
2
2/3BITM
X
[Liu, Thorne 2000]
)T,f(SC)T,f(S ITMX
2FTM
FTMX [Liu, Thorne 2000, Bondu, Hello, Vinet 1998]
#15/54
Nawrodt 05/2010
Thermal Noise - Coating
GWADW2010 Kyoto/Japan
• Thermo-elastic noise:
• Brownian thermal noise:
[Harry et al. 2002]
''2),( ||22 Y
YYY
Ywd
fTkTfS B
x
[Braginsky, Fejer et al. 2004]
)(g1C
Cwd
fTk8)T,f(S
2~2
sS
FS22
2B
TE
2
AVGSS
SFS
S2~
1EE)21(
11
1C2C
FF
F
F isinhRicoshisinh
i1Im)(g
2SS
2FF
2
F CCRandd
note: for the coating Brownian noise the substrate‘s Young‘s modulus is important
#16/54
Nawrodt 05/2010
Thermal Noise – Crystal Orientation
GWADW2010 Kyoto/Japan
[Wortman, Evans, J. Appl. Phys. 36 (1965)]
Selection of the crystal orientation for low noise performance:
)T,f(Yw
1f
Tk2)T,f(S substrate
2
2/3B
X
[e.g. Liu, Thorne 2000]
2 extreme values for theYoung’s moduli of Si:
Ymin = 130 GPa for Si(100)Ymax = 188 GPa for Si(111)
e.g. bulk Brownian noise:
#17/54
Nawrodt 05/2010
Thermal Noise - Overview
GWADW2010 Kyoto/Japan
100
101
102
103
104
10-24
10-22
10-20
10-18
frequency [Hz]th
erm
al n
oise
[m/
Hz]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
20 K
100
101
102
103
104
10-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
300 K
Si(111) test mass, dia. 50 cm, thickness 30 cm, HR stack (20 doublets, Ta2O5:TiO2, SiO2)
#18/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
100
101
102
103
104
10-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
5 K
#19/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
8 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#20/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
10 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#21/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
12 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#22/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
14 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#23/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
16 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#24/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
18 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#25/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
20 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#26/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
22 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#27/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
24 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#28/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
26 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#29/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
28 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#30/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
30 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#31/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
40 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#32/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
50 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#33/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
60 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#34/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
70 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#35/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
80 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#36/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
90 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#37/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
100 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#38/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
110 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#39/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
115 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#40/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
120 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#41/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
125 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#42/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
130 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#43/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
140 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#44/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
150 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#45/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
200 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#46/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
250 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#47/54
Nawrodt 05/2010
Thermal Noise – Temperature Dependence
GWADW2010 Kyoto/Japan
0 50 100 150 200 250 300-0.5
0
0.5
1
1.5
2
2.5
3x 10
-6
temperature [K]
CTE
[1/K
]
300 K10
010
110
210
310
410
-24
10-22
10-20
10-18
frequency [Hz]
ther
mal
noi
se [m
/ H
z]
bulk Brownianbulk TEcoating Browniancoating TEcoating TRtotal
#48/54
Nawrodt 05/2010
Thermal Noise – Adding Suspension
GWADW2010 Kyoto/Japan
Thermal bath
„Universe“
TM
5 m j = 10-4
1 m, dia. 3 mmj = 2×10-9
300 K
5 K
20 K
[S. Hild]
10 km
simplified layout (4 suspended masses):
100
101
102
103
104
10-12
10-10
10-8
10-6
10-4
10-2
frequency [Hz]
mec
hani
cal l
oss
suspension loss (lowest stage):
#49/54
Nawrodt 05/2010
Thermal Noise – Adding Suspension
GWADW2010 Kyoto/Japan
Thermal bath
„Universe“
TM
5 m j = 10-4
1 mj = 2×10-9
300 K
5 K
20 K
100
101
102
103
10410
-28
10-26
10-24
10-22
10-20
frequency [Hz]
ther
mal
noi
se [1
/ H
z]
mirrorpendulumviolintotalET design
sensitivity goal can be reached, additional „help“ is needed at low frequencies (artificial lowering of pendulum frequency needed – actively/passivly)
#50/54
Nawrodt 05/2010
Cooling Issues through the suspension
• cooling through fibre• target temperature: below 22 K
• thermal bath:– technically limited to 2-5 K – no huge advantage to go for 2 K from a thermal conductivity point
of view (limitation through geometry, low thermal conductivity at T < 10 K)
– however, 2 K allows use of suprafluid helium with much reduced mechanical disturbances
GWADW2010 Kyoto/Japan #51/54
Nawrodt 05/2010
Cooling Issues through the suspension
• maximum cooling power is very low (L = 1m, Tbath = 2 K, 4 fibres)
GWADW2010 Kyoto/Japan
Tmirror [K] Diameter [mm] Pmax [mW]20 3 480
5 13008 3400
15 3 2705 7408 1900
10 3 1005 2708 690
#52/54
Nawrodt 05/2010
Cooling Issues through the suspension
• highest possible thermal conductivity needed
• investigation optical absorption in silicon (at 1550 nm unknown)
• strong reduction of introduced thermal load needed
– reduction of incident laser power(Xylophon concept, 2 detectors, low frequency detector with
low laser power e.g. 18 kW)
– very carefull dealing with scattered light needed (additional heating of test masses)
GWADW2010 Kyoto/Japan
[Hild et al. 2010]
#53/54
Nawrodt 05/2010
Conclusion
• crystalline materials are candidate materials for 3rd generation detectors
• cooling necessary to reduce thermo-elastic noise
• high thermal conductivity is used to extract heat, however minimum thermal load should have very high priority (scatter!)
• thermal noise can be reduced below the requirements with reasonable materials (silicon) and R&D (loss measurments, optics absorption, coating research,…)
GWADW2010 Kyoto/Japan #54/54