presentation

Transcription

presentation

Installation of the ring-laser
G-Pisa inside the Virgo area
Angela Di Virgilio, Praha, October 11, 2010
1
• Virgo (3km arm interferometer for
Gravitational Wave research)
• Importance of inertial sensors for Virgo
• G-Pisa Preliminary Data Analysis
2
MAIN REQUIRED UPGRADES
Larger central links
Cryotraps
Heavier mirrors
Higher finesse
3km FP cavities
Waist in the
cavity center
High power laser
Monolithic
payload
Non degenerate
rec. cavities
Signal Recycling (SR)
Intense design activity in
progress to release the
AdV Baseline Design in May
3
Virgo in Short
Larger central links
Cryotraps
High power laser
Monolithic
payload
Signal Recycling (SR)
4
Displacement sensitivity 10-17-10-21 m/√Hz above 10Hz
5
Mirror Suspensions
Measured
Upper Limit
6
Mirror Suspension
Control
Mirror longitudinal swing
reduced to tenths of mm/s
by Inertial Damping
Angular mirror displacements
reduced to fraction of mrad
by Local Controls
7
In few words
• AdVirgo is the next step: a factor 10 improvement
in sensitivity, which is good enough to guarantee
few events in 1 year of data taking
• Virgo suspensions have proved to work fairly well
• Necessary to control the rotation of the upper
stage of the suspension (Inverted Pendulum)
• For that purpose inertial sensors are necessary
with sensitivity 10-8-10-10 rad/√Hz from few mHz
• Virgo has a large experience in linear
accelerometers
8
Beyond AdVirgo (ET)
Rotational inertial sensors embedded inside the
suspension, close to the test masses
Improve the low frequency sensitivity (down to few Hz)
Reduce as much as possible
low frequency large amplitude motion
9
Installation of G-Pisa inside Virgo
• In order to improve the knowledge of
rotational noise inside the Virgo central area
10
11
12
Preliminary analysis
• Details of G-Pisa will be reported in the next
talk (Beverini’s presentation)
• In the following I will describe few graphs
from the preliminary analysis:

few Earthquakes seen by G-Pisa

exercises to cancel the backscatter noise
NOTE: in principle our bandwidth il 1kHz, but so
far we are investigating below 100Hz
13
First data taken in July 2010
14
Typical spectrogram (0-42 Hz)
15
Large EarthQuake in Equador,
August 12, M7.1
Comparison with 3 epicensors
This EarthQuake was so strong that
Virgo interferometer was unlocked
NO strong signal in G-Pisa
16
17
18
Balkan Peninsula, M3.9
Virgo was not working
Comparison with episensors
19
20
Not well seen by accelerometers
21
22
A small nearby earthquake
23
24
-Virgo was not affected by this
-Shock, no evidence of jitter of
the output beam or in the
accelerometers
-But the DarkFring has seen it
25
First exercises of BackScattering subtraction
(very low frequency improvement < 0.1Hz)
26
27
28
Virgo Ty upper Limit
29
Raw Data
Data Values
5.05E-5
5.05E-5
Data Values
5.04E-5
5.04E-5
5.03E-5
5.03E-5
5.02E-5
5.01E-5
5.01E-5
0
10000
20000
30000
40000
50000
60000
index
70000
80000
90000
1E5
1.1E5
Produced by AlaVar 5.2
30
AlaVar 5.2
ADEV
Lower Bound
Upper Bound
Allan STD DEV
1E-7

1E-8
10
100
1000
10000

31
Backscattering
subctracted every 0.5
BackScattering subctracted eack 0.5 hour
Data Values
hour
5E-5
4.99E-5
Data Values
4.99E-5
4.98E-5
4.98E-5
4.97E-5
4.97E-5
0
10000
20000
30000
40000
50000
60000
index
70000
80000
90000
1E5
1.1E5
32
33
BackScattering subctracted every 2 hours
Data Values
4.99E-5
4.99E-5
4.98E-5
4.98E-5
4.97E-5
4.97E-5
4.96E-5
0
10000
20000
30000
40000
50000
60000
index
70000
80000
90000
1E5
1.1E5
AlaVar 5.2
Backscattering subtracted (a fit each 2 hours)
Allan STD DEV
ADEV
HDEV
Lower Bound
Upper Bound
1E-8

10
100
1000
10000

34
From the data it is possible to give
an estimation of monument tilt
35
Conclusions
G-Pisa is running continuously in a quiet
environment
G-Pisa will remain there until summer 2011
Data are acquired inside the Virgo DAQ, so can
be analyzed offline
We are constantly improving our analysis skill
36

presentation

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