Presso la sezione di Roma INFN è attivo da molti anni un gruppo

Presso la sezione di Roma INFN è attivo da molti anni un gruppo che si dedica allo sviluppo di rivelatori sempre più sensibili di onde gravitazionali (non ancora osservate direttamente)
e che oggi fa parte della collaborazione Virgo.
R&D
Proposte @G23 AA 2012‐13
Misura della conducibilità termica (I) e del fattore di qualità meccanico (II)
di fibre di zaffiro (Al2O3)
Majorana, Puppo,
Rapagnani, Ricci
G23, Marconi
ELiTES:
ET‐LCGT Interferometric Telescopes Exchange of Scientists
Work‐Package 1 and 2: cryogenics and suspensions
In construction !!!
The future ???
KAGRA
L 3 km
BOTH UNDERGROUND, CRYOGENICS Einstein Telescope
TRI 10 km
Cryogenic facilities for mechanical quality factor and thermal conductivity at the INFN‐Rome laboratory (University of Rome “La Sapienza”)
Cryogen cryostats (3)
Cryogen‐free cryostats (2),
the most used in last years
E. Majorana
Vibration measurement of the KAGRA radiation shield
Dan Chen, K. Yamamoto, Ettore MajoranaB, Luca NaticchioniB, T. SuzukiA, N. KimuraA, Andrea ConteB, S. KoikeA,
T. KumeA, C. Tokoku, Y. Sakakibara, Alexander Khalaidovski, S. Kawamura and KAGRA Collaboration
ICRR The University of Tokyo, KEKA, INFNB
[email protected]
1.Introduction
The Large-scale Cryogenic Gravitational Wave Telescope named KAGRA is under construction in the Kamioka mine in Japan. The main interferometer mirrors will be cooled
down to 20K in order to decrease the thermal noise. For cooling, each of these mirrors will be surrounded by a double-stage radiation shield to prevent propagation of 300K
radiation and will be connected to two cryocoolers through heat links. The shield vibration can couple into the detector signal via the heat links and scattered light. In order to
investigate the impact on the KAGRA sensitivity, we measured the radiation shield vibration while operating the cryocoolers. Then we estimated the influence on the sensitivity
of KAGRA. Here, we report the measurement result for the KAGRA cryogenic radiation shield vibration and analysis result.
2.Cryogenic payload
Heat links
Radiat ion shield
80K
8K
Baffle
T=20K
2.The scattered laser light is partially
reflected by the baffle (connected
with shield) and might find its way
back into the main laser beam,
contaminating the output of detector.
Cr yo
cooler
Measure the vibration of the radiation shield at low
temperature, and estimate the influence on the
sensitivity of KAGRA.
s
e
is
w
r
io
n
0
8
1
9
1
0
0
h
z
0
9
.e
p
s
5
1
0
Coolers OFF
1
0
1
0
Consistent
with RION
9
1
0
Increase
1
0
1
0
1
8
1
0
1
0
1
0
0
1
1
1
0
1
Calculate the ratio to estimate the
ie
ld
p
e
a
k
a
tk
a
m
io
k
a
0
8
0
7
0
2
0
3
.e
p
s
(
T
=
1
0
K
)
floor level atsh
Kamioka.
7
1
0
f[H
z
]
1
8
1
0
1
0
0
Measurement with coolers ON/OFF (horizontal)
Assume the same peak level at
Kamioka as Yokohama
2
0
1
0
2
2
1
0
2
6
1
0
2
8
1
0
8
V
ib
r
a
tio
n
[m
/r
tH
z
]
1
0
1
1
1
0
1
2
1
0
1
3
1
0
1
3
4
1
0
1
The estimated vibration
of the radiation shield
at Kamioka has peaks
from cryocoolers.
1
0
1
0
2
0
1
0
2
2
1
0
2
4
1
0
2
6
1
0
2
8
1
0
K
A
G
R
A
d
e
s
ig
n
s
e
n
s
itiv
ity
N
o
is
e
fr
o
m
r
a
d
ia
tio
n
s
h
ild
3
0
1
0
1
0
0
1
0
co Ver
m tic
po al
ne
nt
1
1
0
f[H
z
]
f[H
z
]
1
0
0
The noise from the horizontal vibration component is significantly lower than the
requirement. But the noise from the vertical component is higher than the design sensitivity
around 20Hz.
s
h
ie
ld
a
tk
a
m
io
k
a
P
T
O
N
K
a
m
io
k
a
1
0
1
8
3
0
1
0
1
0
d
e
s
ig
n
N
o
is
e
fr
o
m
r
a
d
ia
tio
n
s
h
ild
1
6
1
0
2
4
1
0
3
2
9
1
4
1
0
1
0
1
0
1
0
H
co ori
m zo
po nt
ne al
nt
1
6
1
0
There are many peaks
originating from the coolers.
f[H
z
]
Coincidence measurement with RION (horizontal)
lu
c
a
0
8
1
9
s
tr
a
in
1
0
0
h
z
.e
p
s
1
4
1
0
9
1
0
1
0
1
0
In
s
id
e
th
e
c
r
y
o
s
ta
t
O
u
ts
id
e
th
e
c
r
y
o
s
ta
t
1
1
7
1
0
S
tr
a
in
[1
/r
tH
z
]
T
=
1
0
.1
K
1
0
P
T
O
N
P
T
O
F
F
6
7
We inputed our estimated
vibration to the attachment
points between heat links and
shield.
We estimated the influence on the
sensitivity of KAGRA using a code made
by T. Sekiguchi.
The scattered light effect is not considered.
p
to
n
o
ff0
9
2
5
0
1
.e
p
s
6
1
0
RION
ICRR acc.
INFN acc.
We used a commercial accelerometer(RION) to measure
the vibration outside the cryostat. We measured the
vibration at low temperature with cryocooler ON/OFF.
(Measurement @Toshiba Keihin Product Operations, Yokohama-city).
4.Measurement result and analysis
8
1
0
Inside the shield
1.The vibration of the radiation shield
may excite an oscillation of the test
mass through the heat links.
Cr yo
cooler
The main sources of the
shield vibration:
1. Seismic motion
2. Cryocoolers
V
ib
r
a
tio
n
[m
/r
tH
z
]
We have to take care of vertical vibration when we design the cryo-payload.
1
0
0
f[H
z
]
Measurement of sapphire Q for KAGRA mirror suspension
3.Measurement setup
Heat links (Al 99.999%)
We will use sapphire fibers (φ 1.6 mm) to suspend cooled sapphire
mirrors(20K).
High thermal conductivity → lower cooling time
High Q value → lower thermal noise
Requirements
Thermal conductivity: 5000 W/m/K
Q value: 5x106
etc...
Fiber 1: 5000 W/m/K @20K
Fiber 2: 9000 W/m/K @20K
0
.0
0
0
5
0
0
5
0
0
01
0
0
0
01
5
0
0
02
0
0
0
02
5
0
0
03
0
0
0
03
5
0
0
04
0
0
0
04
5
0
0
0
tim
e
[
s
]
We calculated Q from
the ring dawn signal.
Excite fiber modes
Sensor
4.Measurement result
Requirement (5x106@20K)
7
1
0
Im
p
e
x
M
o
n
o
lith
ic
f1 (
9
4
H
z
)
Im
p
e
x
M
o
n
o
lith
ic
f2
1
(
1
2
6
0
H
z
)
Im
p
e
x
M
o
n
o
lith
ic
f2
2
(
1
2
6
8
H
z
)
Im
p
e
x
M
o
n
o
lith
ic
f3
1
(
3
7
1
2
H
z
)
Im
p
e
x
M
o
n
o
lith
ic
f3
2
(
3
7
4
1
H
z
)
c
a
lc
(
T
E
D
)9
4
H
z
c
a
lc
(
T
E
D
)1
2
6
8
H
z
c
a
lc
(
T
E
D
)3
7
4
1
H
z
6
1
0
5
1
0
Im
p
e
x
N
o
n
M
o
n
o
lith
ic
f1(
8
8
H
z
)
Im
p
e
x
N
o
n
M
o
n
o
lith
ic
f2
1
(
1
2
2
0
H
z
)
Im
p
e
x
N
o
n
M
o
n
o
lith
ic
f3
1
(
3
5
1
5
H
z
)
c
a
lc
(
T
E
D
)8
8
H
z
c
a
lc
(
T
E
D
)1
2
2
4
H
z
c
a
lc
(
T
E
D
)3
5
1
5
H
z
6
1
0
Q
2.Sapphire fiber at Rome
Modal simulation
f1
f2
f3
5
1
0
4
1
0
4
1
0
0.86x106@20K,94Hz
6.4x106@20K,88Hz
3
3
1
0
0
ET meeting 22nd-23rd Oct. 2013 @ Hannover
0
.
0
0
2
0
.0
0
1
5
0
.
0
0
1
Electrostatic act.
7
1
0
Fiber 2
• 9000 W/m/K @20K • HEM quality
• Thermopolishing
• Non-monolithic
• Brazed through alumina
S
ig
n
a
l
f
it
0
.
0
0
3
Wires (C85)
Our purpose is measuring the Q value of these fibers @ 20K
Fiber 1
• 5000 W/m/K @20K
• Monolithic
0
.0
0
3
5
0
.0
0
2
5
Cable of act.
In Rome we tested two samples with good thermal conductivity.
d
e
ti1
0
1
5
0
0
5
a
t1
6
p
4
1
k
r
.
e
p
s
Displacement
sensor
s
ig
n
a
l[
V
]
1.Purpose
Q
Allen Scheie, PA, US
Impact of the radiation shield
vibration on the interferometer noise:
Cooling b ar
Test
mass
Pulse tube
0.9 W at 4K (2nd)
36 W at 50K (1st)
We used an accelerometer developed in Rome Univ. for
vertical direction and a Michelson interferometer as an
accelerometer developed in ICRR for horizontal direction.
S
tr
a
in
[1
/r
tH
z
]
Sapphire fiber
Laser
Dan Chen, Japan
3.Measurement in Toshiba
Cryogenic payload: cooled suspension system and mirror
V
ib
r
a
tio
n
[m
/r
tH
z
]
Due giovani “marziani” discesi nel G23 presso Ed. Marconi a La Sapienza
Hanno portato avanti gl esperimenti,
ma c’è ancora del lavoro da fare (Q meas)!
5
0
Fiber 1
1
0
0
1
5
0
T
[K
]
2
0
0
2
5
0
Low Q
3
0
0
1
0
0
5
0
1
0
0
1
5
0
T
[K
]
Fiber 2
2
0
0
2
5
0
3
0
0
High Q
We measured Q values of two kinds of sapphire fiber whose thermal conductivity is higher than the
requirement value. One of them (fiber 2) has high Q which is higher than requirement value. This
means even non-monolithic fiber can have high Q. HEM quality and thermopolishing might improve
Q value.
Proposte @G23 AA 2013‐14
Progetto R&D per Advanced Virgo/ET
test optoelettronico di una scheda per la rivelazione omodina
di radiazione laser in un apparato di squeezing Majorana,Puppo,
Rapagnani, Ricci
G23, Marconi
SISMICO
NEWTONIANO
TERMICO SOSPENSIONI
TERMICO SPECCHI
PRESSIONE RADIAZIONE
SHOT
RUMORE QUANTISTICO IN UN INTERFEROMETRO MICHELSON INTERFEROMETRO: USA LA LUCE LASER PER MONITORARE LO STATO DI MOTO DEGLI SPECCHI SOSPESI
PRINCIPIO DI INDETERMINAZIONE
SHOT
FLUTTUAZIONE POSIZIONE SPECCHI
X2
RUMORE FASE RADIAZIONE
RUMORE
PRESSIONE
RADIAZIONE X1
RUMORE AMPIEZZA RADIAZIONE
FLUTTUAZIONE MOMENTO SPECCHI
7
RUMORE QUANTISTICO DELL’INTERFEROMETRO 1
h S H O T (ν ) = L
1
h RP (ν ) = mν 2 L
hλ c
2 π Pin
h (ν ) = h
TOT
hPin
SHOT
(ν ) + hRP (ν )
2
2π 3λ c
ν
OTTIMIZZAZIONE ALLA FREQUENZA RISPETTO ALLA POTENZA =
h SQL
2
h
2
2 2
π mL ν
SQL
Popt = π cmλν
2
8
RIVELAZIONE OMODINA
BILANCIAMENTO OTTICO: STESSA POTENZA INCIDENTE SUI DUE FOTODIODI
BILANCIAMENTO ELETTRONICO: STESSE PRESTAZIONI DELL’ELETTONICA DEI DUE FOTODIODI STESSE PRESTAZIONI DELL’ELETTONICA DI SOMMA E DIFFERENZA BASSO RUMORE: ALMENO 10 VOLTE SOTTO LO SHOT NOISE DEL LOCAL OSCILLATOR
PROTOTIPO DI OMODINA
SOMMA
SELF SUBTRACTION
11
TEST DEL PROTOTIPO
MISURA DEL RUMORE ALLE USCITE DEI BLOCCHI E DELLE FUNZIONI DI TRASFERIMENTO
MISURA DEL RUMORE DEL LOCAL OSCILLATOR CON AUTO‐OMODINA
PROTOTIPO DI OMODINA
COMMON MODE
AMPLIFICATORI A TRANSIMPEDENZA
13