Transcript GWADW2015_KazuhiroYamamoto(18May2015)

Thermal Noise and Materials,
Coatings, Optics, Cryogenics
Iain Martin, Michele Punturo, Kazuhiro Yamamoto
Institute for Gravitational Research, University of Glasgow
INFN Perugia
Institute for Cosmic Ray Research, the University of Tokyo
18 May 2014
Gravitational Wave Advanced Detector Workshop
@ Alyeska Resort, Girdwood, Alaska, U.S.A.
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0. Abstract
Tuesday and Wednesday of this GWADW,
there are four parallel sessions.
One of them : Thermal noise workshop
Outlines and topics are introduced.
We need your help for vivid discussion !
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Contents
1.Introduction
2.Short term upgrades
3.Thermal noise modelling
4.Towards cryogenic detector
5.Cryogenics and Materials
6.Flatter beams
7.Coatings
8.Posters
9.Summary
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1. Introduction
Thermal noise :
Fundamental noise source in precious measurement
One of the serious issue in upgrade of
interferometric gravitational wave detector
In our workshop, idea, strategy, current hot topic
about thermal noise will be discussed.
K. Numata et al., Physical Review Letters 91 (2003) 260602
2012
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1. Introduction
In our workshop, idea, strategy, current hot topic
about thermal noise will be discussed.
Our workshop consists of 7 sessions.
In the first half of each session,
invited speakers present “summary” talk to
stimulate discussion.
In the second half of each session, we discuss.
In short, half of our workshop is for discussion.
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1. Introduction
Outline of program
Tuesday morning
Session A : Short term upgrades
Session B : Thermal noise modelling
Session C1: Toward a cryogenic detector
Tuesday afternoon
Session C2: Cryogenics and Materials
Wednesday morning
Session D: Flatter beams and coatings
Wednesday afternoon
Session E : Coatings
Session F : Summary
Thursday afternoon : Iain Martin reports summary.
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2. Short term upgrades
Room temperature second generation interferometer
Fused silica mirror with IBS coating
suspended by fused silica fibers
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2. Short term upgrades
Room temperature second generation interferometer
Fused silica mirror with IBS coating
suspended by fused silica fibers
This has long history since GEO started
development and is enough mature.
C. Affeldt et al., Classical and Quantum Gravity 31(2014)224002.
What kinds of short term improvement is possible
for Advanced LIGO and Advanced Virgo ?
G. Hammond : Advanced detectors solutions for low
thermal noise suspensions
S. Penn : Advanced detectors solutions for low
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thermal noise test masses
3. Thermal noise modelling
3-1. Thermal noise model of reflective coating
Coating itself is complicate system which consist of
two kinds of material layers. Model construction is
not easy.
For example, does loss between layers matter ?
NO : S.D. Penn et. al., Classical and Quantum Gravity 20(2003)2917.
YES (partially): M. Granata et. al., GWADW2012
https://dcc.ligo.org/LIGO-G1200618/public
Current models,
Limitations and possible improvements,
Open questions.
I. Pinto : Modelling the thermal noise
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3. Thermal noise modelling
3-1. Thermal noise model of reflective coating
For example, does friction between layers matter ?
YES (partially): M. Granata et. al., GWADW2012
https://dcc.ligo.org/LIGO-G1200618/public
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3. Thermal noise modelling
3-2. Non thermal equilibrium steady state
Fluctuation-Dissipation Theorem
Relation between thermal noise and loss
It is valid if the system is in thermal equilibrium.
However, it could not be true in some cases.
Some system is in steady state,
but not thermal equilibrium.
Example : Room temperature interferometer
Temperature gradient in mirror
Laser beam absorption
Thermal Compensation System
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3. Thermal noise modelling
3-2. Non thermal equilibrium steady state
Example : Cryogenic temperature interferometer
KAGRA mirror suspended by sapphire fibers
D. Chen
Heat absorbed in mirror
flows along fibers.
16 K
Temperature gradient
in fibers.
22 K
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3. Thermal noise modelling
3-2. Non thermal equilibrium steady state
How much is it different from the FluctuationDissipation Theorem ?
How do we “improve” Fluctuation-Dissipation
Theorem ?
L. Conti : Thermal noise and Non-Equilibrium effects
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3. Thermal noise modelling
3-2. Non thermal equilibrium steady state
L. Conti : Thermal noise and Non-Equilibrium effects
L. Conti et al.,
Classical and Quantum Gravity
27 (2010)084032.
L. Conti et al., Journal of Statistical Mechanics:
Theory and Experiment (2013)P12003.
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4. Towards cryogenic detector
Cryogenic is one of methods to reduce thermal
noise.
Amplitude of thermal noise is proportional to
1/2
(T/Q)
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4. Towards cryogenic detector
CLIO(CLIO, Cryogenic first generation)
First cryogenic interferometric
gravitational wave detector
100m baselines
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4. Towards cryogenic detector
CLIO demonstrated the reduction of thermal noise
by cooling mirrors
T. Uchiyama et al., Physical Review Letters 108 (2012) 141101.
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4. Towards cryogenic detector
KAGRA (Cryogenic second generation)
First km-scale cryogenic interferometric
gravitational wave detector
Cryostat
KAGRA site
Y front cryostat
Cryo duct
Cryocooler
(In total, four cryocoolers)
Construction is in progress.
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4. Towards cryogenic detector
LIGO Voyager (Cryogenic 2.5 generation ?)
Nicolas Smith, Rana Adhikari LSC meeting (March 2015)
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4. Towards cryogenic detector
Einstein Telescope (Cryogenic third generation)
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4. Towards cryogenic detector
Thermal fluctuation of vertical motion of suspended
mirror is an issue.
S. Reid: DLC coated silicon cantilever blade springs
for improved vertical suspension thermal noise
performance for future GW detectors
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5. Cryogenics and Materials
Cryogenic interferometer sounds attractive.
However , there are some open issues.
Cooling technologies should be considered
carefully
(operating temperature, cooling time, open
questions …).
K. Yamamoto : Cryogenic interferometer
technologies
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5. Cryogenics and Materials
Room temperature second generation interferometer
Fused silica mirror suspended by fused silica fibers
(amorphous)
This suspension is not a good for cryogenics
because of large mechanical dissipation
and low thermal conductivity at low temperature
Other material with small dissipation
and high thermal conductivity
Sapphire or Silicon (Crystal)
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5. Cryogenics and Materials
Silicon bulk
Sapphire bulk
for KAGRA
About 220 mm diameter,
150 mm thickness
450 mm
300 mm
Harald Lueck(ELiTES meeting 2013)
https://events.egogw.it/indico/conferenceOtherViews.py?view=standard&confI
d=7
Source:
http://www.iisb.fraunhofer.de/content/dam/iisb/de/images/geschaef
tsfelder/halbleiterfertigungsgeraete_und_methoden/gadest_2011/
R. Nawrodt : Materials for suspensions and test
masses in a cryogenic detector
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5. Cryogenics and Materials
Absorption in mirror is a crucial issue (In the worst
case, mirror can not be cooled !)
J. Degallaix: Optical Absorption on substrates
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6. Flatter beams
Larger beam is one of method to reduce thermal
noise.
When beam is larger, thermal fluctuation in wider
area is averaged. Since correlation between
fluctuation at two points is smaller when the
distance is longer.
(Exception : Thermoelastic noise at low temperature.
Correlation is almost perfect because of extremely
high thermal conductivity)
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6. Flatter beams
M. Tacca: High order mode beams
M. Granata et al.,
Physical Review Letters
105(2010)231102.
L. Carbone et al.,
Physical Review Letters
110(2013)251101.
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7. Coatings
20 years ago …
Nobody cared coating thermal noise because it is
10000 times thinner than mirror thickness.
However, Levin’s breakthrough paper pointed out it
could be an issue !
Y. Levin, Physical Review D 57(1998)659.
Analytical and numerical calculations and
measurement show it should be an issue !
G.M. Harry et al., Classical and Quantum Gravity 19(2002)897.
N. Nakagawa et al., Physical Review D 65(2002)102001.
K. Yamamoto et al., Physics Letters A 305(2002)18.
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7. Coatings
First observation of thermal noise by coating
K. Numata et al., Physical Review Letters 91 (2003) 260602
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7. Coatings
The book about coating
thermal noise
was published on 2012 !
Cambridge University Press
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7. Coatings
Progress in the last 20 years
Many people investigated conventional dielectric
multilayer coating (IBS).
The loss angle is on the same order of magnitude
(10-4) even if coating is cooled.
Crystalline coating has much smaller loss (10-5), but
open questions for large mirror.
G. Cagnoli: Review talk on the status of the art and
known limitations
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8. Posters
Three posters
They also give short introduction oral talk in our session.
Peter Murray : Low-temperature mechanical dissipation of
thermally evaporated indium film
(Mariëlle van Veggel or Iain Matin give presentation, Tuesday
morning)
Mariëlle van Veggel : Current status of the bonding research
for silicon and sapphire (cryogenic) suspensions(Tuesday
afternoon)
Jessica Steinlechner : Optimization of Si-based HighlyReflective Mirror Coatings for 1550 nm(Wednesday
afternoon)
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9. Summary
Thermal noise workshop (Thermal Noise and
Materials, Coatings, Optics, Cryogenics) on Tueday
and Wednesday.
7 sessions (Short term upgrades, Thermal noise
modelling (coating, non thermal equilibrium),
Cryogenics, Flatter beams, Coatings)
Half of our session is for discussion.
We need your help for vivid discussion !
3 posters (They give short introduction oral talk)
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Thank you for your attention
and let us enjoy discussion !
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8. Posters
Mariëlle van Veggel : Current status of the bonding research
for silicon and sapphire (cryogenic) suspensions
Peter Murray : Low-temperature mechanical dissipation of
thermally evaporated indium film
Stuart Reid : DLC coated silicon cantilever blade springs for
improved vertical suspension thermal noise performance for
future GW detectors?
Jessica Steinlechner : Optimization of Si-based HighlyReflective Mirror Coatings for 1550 nm
Julius Komma (Jena)
Electronical Absorption of Silicon at Cryogenic Temperatures35
3. Thermal noise modelling
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5. Cryogenics and Materials
Sapphire bulk
for KAGRA
About 220 mm diameter,
150 mm thickness
https://www.tum.de/en/abouttum/news/pressreleases/short/article/31391/
R. Nawrodt : Materials for suspensions and test
masses in a cryogenic detector
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