Post on 17-Jan-2016
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
Analysis of noise in VIRGO
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
What we mean for “noise analysis” How is the noise analysis work organized in Virgo Which tools Noise and data analysis groups What has been done Some results in noise identification Sensitivity curve debugging (noise understanding)
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
What we mean for noise analysis
VIRGO commissioning: interferometer still in a development phase the Interferometer’s configuration is progressively upgraded
The sensitivity is measured through the output signal calibration
We try to identify the different sources of the noises
We try to upgrade things in order to reduce the identified noise source
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
Work organization
Engineering runs: allow collection of data (3-5 days every 2 months)
Data Analysis: division in investigation groups (normally 3-4 persons with a coordinator)
Discussion of the results in data analysis meetings
Depending on the results, the further activity is decided (implementations, modifications, etc.)
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
Summary of the performed activity
CITF (2000-2002): Five engineering runs (E0-E4)About 5-10 investigation groupsAbout two meetings after each run
VIRGO (2003-now):Four Virgo runs up to now (the last at the end of June)About 10 investigation groupsNormally one preliminary meeting short after the run, then a
more detailed one
http://wwwcascina.virgo.infn.it/commissioning/Eruns.html
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
Engineering runs
4 VIRGO Engineering runs (C1-C4, now five days each)
C1 (14-17 November 2003): North Arm locked
C2 (20-23 February 2004) : North Arm locked+linear alignment; West Arm locked
C3 (23-27 April 2004) : North Arm locked+linear alignment+second stage frequency stabilization; Recombined locked (lock acquisition mode, no linear alignment)
C4 (24-29 June 2004): Recombined+linear alignment on both arms+second stage frequency stabilization
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
VIRGO sensitivity curve
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
Progress in sensitivity
10 100 1000 1000010-20
10-19
10-18
10-17
10-16
10-15
10-14
10-13
10-12
10-11
10-10
10-9
10-8
C1 (North Arm) C2 (North Arm) C3 (North Arm) C3 (recombined) C4 (recombined) Design
m/s
qrt(
Hz)
Hz
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
Investigation groups
Individuated investigation groups:(http://wwwcascina.virgo.infn.it/DataAnalysis/Noise/)
Present list of the groups:
– Calibration– Locking performances and noise – Alignment performances and noise – Suspension control performances and noise – Environmental noise – Laser noise – Glitches search and identification – Lines identification – Quantify noise stationarity/gaussianity – Readout noise
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
Tools
Data are in the Common Data Frame Format for Interferometric Gravitational Wave Detectors
Mostly handled with:
dataDisplay: data visualization and analysis Siesta: simulation vs data Vega: data visualization and analysis Other (personal) softwares and/or libraries
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
dataDisplay
dataDisplay: Virgo software for visualizing and analyze data
It is the most commonly tool used by commissioning people.
It allows on-line (in-time) data analysis and visualization It allows visualization of measured and simulated data It has ist own routines for analysis (FrVect: offsets, sum,
multiplication, FFT, coherence,TF, etc.)
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
Siesta
Siesta: Virgo software for simulation
C written code with C input cards It allows the simulation of the whole interferometer (optics,
mechanics, etc.) in the time domain It has its own routines for analysis (FFT, coherence, TF,
…) It allows simulation of control loops: simulated data in
frame format can be compared with the measured ones (e.g. with dataDisplay)
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
VEGA
VEGA:
Graphical software, based on ROOT (Cern), modified to handle data in the Frame format (Frame library and FrVect)
Allows off-line data visualization and analysis
Less used by commissioning people than dataDisplay
It is linked to the Cernlib libraries for data analysis
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
Others
Many people working in noise analysis have developed their own routines and libraries (Matlab, C and C++ software).
Some examples:
Lines identification: Florence-UrbinoNon-linear, non-stationary: Nice, UrbinoLines removal: LAPPWhitening: EGO
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
Common library
Since there is much dispersion, discussion is going on in Virgo in order to create a common library for noise (and data) analysis.
For the moment no final common reference software has been established yet
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
Examples of noise investigation
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
Environmental sensors
3km
3km
Central building
MC End b.
West End b.
North End b.Low Frequency Accelerometers
Tri-axial, 0.2-200 Hz
(Kinemetrics - “Episensors”)
High Frequency Accelerometers
Vertical Piezo, 10-10000 Hz
(Bruel&Kjaer)
Other Environmental probes:
• Microphones• Magnetometers• Pressure probes• Humidity • Temperature • Weather station
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
LF seismic activity monitoring
Episensor (tri-axial accelerometer) in the central Building
Updated on web each 10 minutes
Sea activity
Human activity(road traffic on highway bridges)
Human activity around the site
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
Acoustic noise in the detection laboratory
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C1 (North Arm)
Electronic noise
Shot noise
MC length control noise
MC length noise
Mirror control noise
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C2 (North Arm)
Shot noise
ADC noise
MC length control noise
MC length noise
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C2: spectrogram 150 Hz-3 kHz
Decrease of noise Noise is higher than it was before the decreasing period
Noise at beginning
of C2
ZOOM
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
Effect of the pump
Between 13h22 (UTC) and 14h40, all pumps are progressively switched off
At 13h59, IB pump switched off
ZOOM
Between 14h40 and 15h00, original conditions are restored
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C3 : scroll pumps OFF (IB), except 5min/day
C2
C3
Residual env. noise dominates mainly in [1500, 3000]Hz Turbo pump (mainly IB) ?
IB tower accelerometer
Coherence with dark
fringe
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C2: Mirror internal modes identification
Coloured noise injected at the RM actuators of each mirror
ANSYS mirror simulation Calibration software (CaRT) One period at the NA and another at the WE Mirror internal lines and quality factors measured
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C2: North mirror internal modes identification
NI:3917.2 Hz5584.7 Hz
NE:3883.0 Hz5542.2 Hz
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C2: Mirror Internal modes measurement
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C4: Thermal noise
5542 5543 5544 5545 5546 5547 554810-12
10-11
10-10
Am
plitu
de
Frequency [Hz]
PrB1ACp
End mirrors
Internal modes are now visible in the ITF output(recombined ITF)
NE at 5543 Hz WE at 5545 Hz
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C3 (North Arm)
With SSFS :
RFC noise contribution is reduced
C3 sensitivity now limited by another
kind of noise
FFT(Sc_NE_zGc) x Mechanical TF(NE)
C2 sensitivity limited by RFC
noise
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C3 (North Arm)
Pr_B1_ACp spectrum (April 23rd, 20:00:00 UTC )
Electronic Noise
Shot Noise
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C3: Injection Bench lines (10 Hz< f < 100Hz)
Input Bench resonances
Good coherence around the IB resonances
introduced in the sensitivity by the IMC AA loop
Sc_MC_txCorrM Sc_MC_txCorrR
Sc_MC_tyCorrM Sc_MC_tyCorrR
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C3-Recombined: Electronic Noise
Pr_B1_ACp spectrum (April 27th, 12:20:00 UTC )
Electronic Noise (measured with shutter closed)
Shot Noise
Additional noise
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C3-Recombined: West terminal photodiode (B8) noise
Hz
Gain
frequency
Transfer function of the standard filter
Static gain = 1.727 x 10ˆ9
West arm
B8_phase/B8_DC
Sc_WE_zCorr
Filter
Pr_B8_ACp limited by electronic
noise above 200 Hz
injected in sensitivity by
the control loop
Pr_B8_ACp used to acquire the lock of the
West Cavity
Coherence between B1_ACp & B8 _ACp
sensitivity limited by B8 electronic noise between 200 Hz & 1
kHz
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C3-Recombined: West terminal photodiode (B8) noise
Standard filter
New filter
frequency
Phase
|gain|
Roll off @ 300 Hz
B8 noise model suits to sensitivity curve
between 200 & 1000 Hz
New noise structures
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C3 Noise limitation to the sensitivity curve
1 - North arm
High frequencies : Electronic noise(?) or noise coming from the ITF (?) Above 250 Hz : not well understood Between 10 & 250 Hz : coherence with the correction signals used by the IMC RFC noise (NA length control loop): does not limit C3 sensitivity, but could
limit the sensitivity below 50 Hz for full VIRGO
2 - Recombined configuration
High frequencies : electronic noise 200-1000 Hz : noise due to B8 10-100 Hz : “laser frequency noise” but is reduced at the end of the run
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
C4 General results about sensitivity (C4 data still to be discussed)
Paolo La PennaILIAS N5-WP1 meetingNoise analysis in Virgo
Cascina, 7-8 July 2004
Summary
Virgo is not in its final configuration: Noise identification means debugging the progress of the activity
The commissiong activity for noise analysis is mainly concentrated on the data from the runs, in identifying the noise sources in the sensitivity curve
Many tools for analysing noise are present, discussion is going on for establishing a common library