The GW detector Mario Schenberg -...

EPFL/ LPHE 6th Oct. 2014, C.F. Da Silva Costa

The Mario Schenberg detector

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Carlos Filipe Da Silva Costa(Post-doc, scholarship PCI)

The GW detector Mario Schenberg

EPFL/LPHE, 6th October 2014Schema of the Mario Schenberg detector



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The next 3 years (max 2022) will be decisive for the gravitational waves: first detection?

If yes, you will have an incredible amount of information about astrophysical phenomena.

The GW detector Mario Schenberg



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- A brief introduction to GW - Which kind of detectors- Mario Schenberg, a close view- Present activities before the RUN!- What we (I) hope for the future- Conclusions

Plan

Schema of the Mario Schenberg detector

EPFL, 6th Oct. 2014, C.F. Da Silva Costa

Mario Schenberg detector

Introduction to gravitational waves/ Sources 1/3

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SuperNovae http://relativity.livingreviews.org/




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Inspiraling BH-BH, NS-NS and BH-NS



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Periodic sources (NS)

- fainter than burst ~103 times less.- integrated over long periods (excess in the

frequency spectra).



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Introduction to gravitational waves/ Sources

Summary:

- Inspiraling neutron star (NS) and black hole (BH) binaries.

- Tidal disruption of a NS by a BH- BH+BH mergers and ringdowns- Supernovae- Gamma-ray bursts (hypernovae or NS-NS

BH-BH) - Spinning neutron stars (pulsars, LMXB’s)- cosmological sources

- and we don’t know!

ref: http://www.ligo.caltech.edu/advLIGO/scripts/ref_des.shtml

http://www.ligo.caltech.edu/advLIGO/scripts/ref_des.shtml



Introduction to gravitational waves/ Indirect detection

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Our proof!

Joseph H. Taylor Jr. and Russell A. Hulse

- One pulsar (PSR 1913+16) in a Neutron Star (NS) binary system.

- The cumulative shift in the periastron period

- 30yr: Observation in perfect agreement with General Relativity predictions.

Nowadays, we have 4 binary systems with one pulsar and one system with two pulsars!

Orbit of a binary system




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Our proof!






Orbit of the pulsar




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Our proof!








Detectors/ Detection principle

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In the reference frame of the laboratory thedeviation between two geodesics is given by

- in terms of the h matrix

Metric = Minkowski’s metric+perturbation

Wave equation of the metric perturbation




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h+

hx

Effect of GW on free test masses

x

x

y

y

- in our laboratory: ~Newtonian force acting on particles (test masses).




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h+

hx

Effect of GW on free test masses

x

x

y

y

To make it more clear! The effect of theses forces is

which means that for our sphere, we 10^-22m amplitude displacements!



Detectors/ Interferometers

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Test mass mirror

Schema of interferometer (LIGO)

The Virgo detector



Detectors/ Resonant bar

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Resonant bar

CapacitiveTransducer

Liquid nitrogen

Schema of a resonant bar detector

Detector Nautilus

Liquid Helium

SQUIDsAmplifier

Attenuators



Detectors/ Distributions

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<<

<

<

<

<

<

LIGO Hanford

LIGO Livingston(Alegro)

Virgo Italy

IndigoKAGRA

(AIGO)

Geo600 Germany(Explorer) Switzerland

Nautilus &Auriga Italy

MiniGRAIL Netherland

Mario Schenberg Brazil



Mario Schenberg/ A spherical detector

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MiniGRAIL, Leiden, NetherlandsMario Schenberg, São Paulo, BrazilSchema of interferometer (LIGO)



Mario Schenberg/ Working principle

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- weights 1150kg - measures 65cm ∅- high mechanical Q

alloy: CuAl(6%).




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Particularity: GWs (hij) couple with the 5 quadrupolar mode of the sphere.




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TIGA configuration Six tansducers monitoring Converting transducer oscillations intinto hm

Particularity: GWs (hij) couple with the 5 quadrupolar mode of the sphere.



Mario Schenberg/ Working principle/ Parametric Transducers

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Schema of the last (6th) transducers Conversion of the sphere mechanical vibrations into electro-magnetic signal. These transducers contain Klystron type cavities: - the carrier frequency is 10GHz- df/dx=0.5GHz/µm- 3 masses/ three modes

- antenna effective mass (287.5 kg)- structure of the transducer (~ 25 g)- a membrane (~ 2 mg)

The goal-> high electric quality factor Qe (∼3x10^5) and mechanic quality factor Qe (~2x10^8)

Problem: could only be tested when the cavity is supra conductive!

Odylio et All, Amaldi 2011, JPCS




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The strain sensitivity is the sum of all noises.- thermal noise- Seismic - phase noise (signal carier)- serial noise (amplification

system)- backaction

Bandwidth: ~80Hz around 3.2kHzStrain sensitivity: ~10-21 Hz-1/2

Frequency [Hz]

Stra

in s

ensit

ivity

[Hz-

1/2 ]

Theoretical strain sensitivity of Mario Schenberg




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Schema of the Mario Schenberg detector To cancel seismic vibration the detector is equipped with a dumping system.

5 masses act as a pendulum (~130 kg)

Seismic noise attenuation: 320dB




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Schema of the Mario Schenberg detector The thermal noise is canceled by cooling down the system using Nitrogen and then liquid Helium.

It will take 3 weeks to cool down till 1K. (~10 mk)

The system is isolated from thermal radiation and conduction by 3 dewars and vacum between them.



Mario Schenberg/ Next run

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The last runs were performed during the period 2006 to 2008. The setup was tested with just three initial designed transducers.

Since then,- new transducers (6th)- new amplification circuit- we are going to cool down at 1k

instead of 5k- lift system for dewares- new data acquisition system- we added a cosmic ray veto

!



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Schema of Amplification signal circuit (as planned) The amplification signal circuit was installed and tested during the last months.

- Sapphire oscillators-> signal carrier 10GHz.- low phase noise- increase frequency stability- synthesizer shift the frequency to the

transducer resonance

!

change to copper

Mario Schenberg/ Next run/ Signal amplification

probe

Later..




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Cryogenic amplifier The red features are the connectors between plates.

Cables from outside the cryogenic part




Temporary cables between 1k pot plate and the sphere suspension Final cables integrating seismic insulation




Positioning a transducer View of the probe support




Signal generators 10GHz Audio amplifiers for signal of ~3KHz (last stage before DAQ)



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Mario Schenberg/ Next run/ DAQ

The Data Acquisition System is composed of:- ADC converter board: VT1436.- GPS receiver for time reference.- PC interface: Agilent plate (VXI->FireWire).

Features:- Sampling 15625Hz- 6 channels- Floats (4bytes) -> amount of data per day: ~30GB reduced to 300MB of data per day

Pictures of the three DAQ boards



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Preparing cables (TFP->ADC) Testing the DAQ with function generator

coaxial SMB




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The control room We have installed two PCs:- data acquisition- analysis and sends the data.

Transmission 31.4 ±1,4MB/s. Acquisition rate 1,3MB/s.

This configuration is optimized for low latency analysis.




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Preparing the control room. Replacing a old server



Mario Schenberg/ Next run/ Cryogenic

View of the thermal sondes The Pt1000 and Ru02 will monitor many points




View of the dewars with the floor open Testing the system to lift the 3 dewars




Testing the system to lift the 3 dewarsTesting the system to lift the 3 dewars



Mario Schenberg/ Next run/ Cosmic rays veto

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Photo of the astroparticle shower setup Astroparticle showers are a source of noise.- energy deposition in the sphere - like a calorimeter but sensitive to neutral

particles.

Veto installed in November 2011- three scintillators (in function now)

See: - Thesis Denis Borgareli (2013)- R. Marinho, CQG, (2001)- C.F. Da Silva Costa et al, NIM (2014)



Mario Schenberg/ Next run/ Cosmic rays veto

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Photo of the DAQ of the cosmic ray veto During the next run, the 3 scintillators will be placed below the sphere. - > coincidences between event in the sphere a cosmic ray showers.



Mario Schenberg/ Future/ What we expect?

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In a close future,- 3 weeks cooling- the setup works or not?- continue to develop the

detector, corrections and adjustments

We do not expect any detection. - not competitive(Bandwidth: ~80Hz around 3.2kHz, Strain sensitivity: ~10-21

Hz-1/2)

S Hild, Class. Quantum Grav. 29 (2012) 124006 (9pp)

Schenber



Mario Schenberg/ Future/ What we expect?

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Future (2016-2020),But we hope that aLIGO will do detect something.

Advanced LIGO–Virgo network: ~40 events per year (0.4 and 400 per year)

Ligo, Class. Quantum Grav. 27 (2010) 173001 (25pp).

S Hild, Class. Quantum Grav. 29 (2012) 124006 (9pp)

Schenber



Mario Schenberg/ Future/ Let’s do what we know best!

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We are better for fast GW source localization!

The main advantages:- Six detectors in one!- The sphere is isotropic.- We have the GW arrival direction and polarisation.

-> A sphere is well designed for GW astronomy.

As soon as one detection is confirmed, the Schenberg detector technology will interest small groups.It’s like small telescopes available for universities, when aLigo and aVirgo are Hubble telescopes.

z x

y

(θ,φ) GW direction



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Mario Schenberg/ Future /New Low latency

Multi-messenger analysis:- confront possible GW with other

astrophysical messengers X,γ,ν etc- GW direction in few second with a good

confidence.

We are improving our pipeline (CUDA, more sophisticate filters).

Event messenger accompanying GW emissions



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Mario Schenberg/ Future / New Low latency

Second program

First Program

Defining periodograms, set of data

Conversion From courant "i" to mode

channels "h".

SNR>10No

Yes

The data are cut in set called periodogrames of 30s or 60s. Thus lenght =N

Cutting the frequency band

Each sample is multiplied by a 6x6 matrix

Averaging (weighted) the previous data The new periodogram is

compared with the averaged previous periodograms

Computing the SNR of the selected band

Reeceving in continous the data: Currents "i".

Each sample is a double. 6xchannels at 15625 Hz

The data are save for the next process

Selecting the samples having

SNR>10

Computing the GW direction

Arrays [6][N] my format is: mG_multi_Ch Actually: double **data;

FFTw

In: my format is: mG_multi_Ch Actually: double **data;] Out: my format is: mG_multi_Ch_cplx Actually: double ***data;

In the code I defined the following type: mG_Ch mG_Ch_clpx mG_multi_Ch mG_multi_Ch_cplx Which are actually: double *data; [N] the number of data double **data; [N][2] 2 for real and imaginary double **data; [6][N] 6 number of channels double ***data; [6][N][2] 6 channels of N complex number. the definition is in my class "mG_Functions.hh"

FFTw

my format is: mG_multi_Ch_cplx Actually: double ***data; M reduced number of data

In: my format is: mG_multi_Ch_clpx Actually: double ***data; [6][N][2] Out: my format is: mG_multi_Ch_cplx Actually: double ***data; [6][M][2] M reduced number of data.

my format is: mG_multi_Ch Actually: double **data; N NOT reduced number of data

Computing the GW Polarisation

Veoting trigger

my format is: mG_Ch Actually: double *data; [X] Where X is the number of selected samples. The 6 channels are summed to give the spectral power.

Both operations (left) use the selected samples and the information of the direction. Both outputs are simple values.

Giving all the parameters of the GW.

GPU

GPU

GPU

GPU

GPU GPU

GPU

Principal program

Second program

First Program

Direction 1 vector Histogram Average value +variation



Selected samples with SNR>10

Pondering each sample with its SNR

Selecting the lower variation

Computing the direction

Giving the direction with its error

my format is: mG_Ch Actually: double *data; [X] Where X is the number of selected samples. The 6 channels are summed to give the spectral power.

Actually: double *data; [X] Same datas as above

Each sample (of the X selected samples) is converted in vector, an array double[3] We have 3 different equation for the direction. For each direction 3 histograms are filled with the vetor components. The output are 3 sets of values with the average direction and its standard variation.

The systematic errors are corrected

GPU

Veoting the trigger

The data of the band in real domain

The GW direction

Constructing simulated data based on the possible GW direction.

Expected signal

Comparing both real data and the

expected signalIs the signal

vetoed

mG_multi_Ch double **data; [6][M] M reduced number of data.

GW direction value

Veoted: We use a thereshold

on the difference

No

Yes

GPU

Principal program Two subroutines Adding the new part of Matched Filter (MF)

The data of the band in cplx domain

The GW previous paramters (direction, polarisation,

frequence, time)

Constructing simulated signals based on the possible GW direction.

Expected signal

Multipling the data by the expected GW shape. The parameter values are varied into a defined space.

mG_multi_Ch double ***data; [6][M][2] N reduced number of data.

GW direction value

mG_multi_Ch double ***data; [6][M][2] N reduced number of data.

Computing the SNR of each variation

The parameters maximazing the SNR

GPU

GPU

Two subroutines Future addition to the main program



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Mario Schenberg/ Future / Transducers

Study of feasibility of a nanogap transducer is projected -> larger bandwidth

The goal is 1nm (bandwidth from 50Hz to 1 kHz)!

sapphire40 mm diameter30 mm hight

0 2000 4000 6000 8000 10 00010!24

10!22

10!20

10!18

Frequency !Hz"

StrainNoiseSpectralDensityh"#1 H

z

$



Conclusion/

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A tremendous work was done and NOW what happens?

New transducers? I am also looking for new ideas? how to measure manometric displacements? New low latency pipeline using CUDA.We will improve it.

The aim of the Gravitational Waves (GW) study is to provide a new source of astronomical information and spherical detector is well designed for it.

We are hoping to start the field in 2017!



Presentation/ End

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