Survival kit to ground based detectors Nicolas Leroy Laboratoire de - - PowerPoint PPT Presentation

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Mar 11, 2023 208 likes •395 views

Survival kit to ground based detectors Nicolas Leroy Laboratoire de lacclrateur linaire dOrsay What are Gravitational waves ? 2 Suspended interferometer det = P in ( ) P 2 1 + C cos( ) C = 2 r 1 r 2 2 + r 2 r 1 2

SLIDE 1

Survival kit to ground based detectors

Nicolas Leroy Laboratoire de l’accélérateur linéaire d’Orsay

SLIDE 2

What are Gravitational waves ?

SLIDE 3

Suspended interferometer

≡ ΔφOP ≡ δφGW P

det = P in

2 1+Ccos(ΔφOP)−Csin(ΔφOP)×δφGW (t)

( )

det = P in

2 1+Ccos(Δφ)

( )

Δφ = 2π l2 −l1

( )

λ + 2π l2 +l1

( )h(t)

λ C = 2r

1r 2

1 2 + r 2 2

SLIDE 4

Limiting noises

Pendulum noise Mirror thermal noise Violin mode, resonances from the wire

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Quantum noise

@ P.-F. Cohadon

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Quantum noise in GW detector

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Increase sensitivity : optical path

@ J. Degallaix

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Increase sensitivity : location, materials and quantum noise

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Main challenges for a detector on Earth

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Advanced generation detector

Michelson interferometer Goal : (Lx-Ly)/Lx = 10-23

High power laser High quality

ptics – 40 kg

Surface RMS ~nm

Fabry-Perot cavities

Suspended Optics

ARenuation 1014 @ 10 Hz

Full system under vacuum ~10-12 atm Feedback loops from few Hz to few kHz

200 W

Mode matching Spatial filtering @LMA @LAPP @ARTEMIS @APC

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Targeted sensitivity

Contribution of main sources of noise Different SR configurations

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All-sky detector

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Current status

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Post O3 program: Advanced Virgo +

KAGRA LIGO India (same as LIGO at the same time) LIGO Voyager ?

Frequency/Hz Strain noise amplitude/Hz−1/2 Advanced Virgo

Early (2016–17, 20 – 65 Mpc) Mid (2018–19, 65 – 85 Mpc) Late (2019–20, 65 – 115 Mpc) Design (2021, 125 Mpc) BNS-optimized (140 Mpc) 101 102 103 10−24 10−23 10−22 10−21

Signal recycling squeezing

coating

SLIDE 15

Moving to next generation

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Possible scenario

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