LIGO-G050470-00-Z

Guido Mueller University of Florida

For the LIGO Scientific Collaboration

ESF Exploratory Workshop Perugia, Italy September 21st –23rd, 2005

Status Report

LIGO

LIGO

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Table of Content

Layout Seismic Isolation

» Suspension system» HEPI

Interferometer» Wavefront Sensor» Thermal Correction System (TCS)» Laser situation

Science Output» Sensitivities/Papers at different Science

Runs S5-Plans

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LIGO Layout

Power-recycled, cavity-enhancedMichelson Interferometer

Arm Cavities:• Livingston: 4km long• Hanford: 4km and 2km longTITM = 2.7%, Finesse ~ 115

Power Recycling mirror:TPR = 2.7%, Gain ~ 50

Mirrors:• Material: Fused Silica• 25 cm diameter• 10 cm thick• Wedged (~2deg)

225W

15kW

5W

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Seismic Isolation

Optics suspension: Single steel wire pendulum

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Seismic Isolation

Optics suspension: Single steel wire pendulum

» Normal modes:– Pendulum: ~0.74 Hz

– Yaw mode: ~0.5 Hz

– Pitch mode: ~0.6 Hz

– Roll mode: ~18 Hz

– Violin mode: ~345 Hz

Coil-magnet actuation» Magnet on optic» Coil on support frame» Includes shadow sensor

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Seismic Isolation

Optics suspension: Single steel wire pendulum

» Normal modes:– Pendulum: ~0.74 Hz

– Yaw mode: ~0.5 Hz

– Pitch mode: ~0.6 Hz

– Roll mode: ~18 Hz

– Violin mode: ~340 Hz

Coil-magnet actuation» Magnet on optic» Coil on support frame» Includes shadow sensor

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Seismic Isolation

Vibration Isolation System:» 4 layer passive isolation stack

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Seismic Isolation

• Attenuation of 120dB above 50 Hz• High-Q resonances between 1.5 and 12 Hz amplify external noise (falling trees and trains at LLO).

Solution:HEPI (Hydraulic Actuator External Pre-Isolator)

Low Duty cycleuntil S4

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Livingston Seismic Problems

Caused by human activity:Cars,

Trains, Trucks,

Logging, Well Drilling,

Oil Pipeline

Amplified byinternal isolationstack resonances

99

Ocean activity, hurricanes

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HEPI

Quiet Hydraulic Acuators 3 Sensors, 2 crossovers Position sensors for DC lock Ground sensor for low freq. correction Payload geophone for high frequencies

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Helical Spring

Vertical Actuator

HorizontalActuator

Crossbeam

Pier

Input Test MassChamber

Improved Duty cycle:S3 S4

L1: 22% 75%H1: 69% 81%H2: 63% 81%

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Wavefront Sensing

System measures & controls mirror (core optic) pitch & yaw angles» Complication: each sensor is sensitive to alignment of multiple

mirrors

» Before and during S4, the servo bandwidths was very low

» Current status: Mixing of control signals is carefully tuned to decouple the WFS channels from each other

» Increased gain and bandwidth (2-4 Hz for ITM and ETM)

Main benefit: reduces the orthogonal phase signal at the anti-symmetric port (ASI), allowing higher power operation

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Thermal Correction System

CO2 Laser

?Over-heat mask Under-heat mask Inhomogeneous mask

ZnSe Viewport

Over-heat pattern

Under-heat pattern

Raw Heating pattern

• TCS is very effective in correcting up to 100 mW of absorption in ITMs

• Had still problems with 4k ITMX in Hanford (high absorption?)

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Thermal Correction System

Replaced ITMX in Hanford Beam size measurements repeated.

Power needed to correct thermal lensing:

Now, we can increase the input power into interferometer.

ITMX ITMY

Before 35 mW/W 13.5 mW/W

Now < 3 mW/W 3 mW/W

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Laser Situation

Hanford:

H1: Laser replaced in April 2004 Power output: 11W (without any degradation since April 04)

H2: Original laser, running since October 1998 Replaced Master laser early this year Power output: 7W (scheduled for replacement soon)

L1:

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Hardware Status

Summary:

Seismic Isolation now active (HEPI)» Improved duty cycle

Wavefront Sensors tuned and activated» Larger bandwidth in control loops

» Enables higher power operation

Thermal Correction System installed and “dirty” mirror replaced» Enables higher power operation

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Data Runs

S1 run: 17 days (August / September 2002)

S2 run:

59 days (February—April 2003)

S3 run:

70 days (October 2003 – January 2004)

S4 run:

50 days (February – March 2005)

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Sensitivities

Initial LIGO Design

S1 (L1)1st Science Runend Sept. 2002

17 daysS2 (L1)2nd Science Runend Apr. 2003

59 days

S3 (H1)3rd Science Runend Jan. 2004

70 days

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Lets look into this noise

3.5 Mpc7.3 Mpc8.4 Mpc

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Noise Upconversion

Using HEPI, increase the suspension point motion at 1.5 Hz by a factor of 5

DARM noise increases by a factor of ~5 over a wide band

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BANG!

Binary systems» Neutron star – Neutron star» Black hole – Neutron star» Black hole – Black hole

Periodic Sources» Rotating pulsars

“Burst” Sources » Supernovae» Gamma ray bursters» ?????

Stochastic» Big Bang Background » Cosmic Strings

Data Analysis

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Science

S1: Aug. 23 – Sep. 9 2002, 17 days» Setting upper limits on the strength of periodic

gravitational waves from PSR J1939+2134 using the first science data from the GEO 600 and LIGO detectors, Phys. Rev. D69: 082004 (2004).

» First upper limits from LIGO on gravitational wave bursts, Phys. Rev. D69: 102001 (2004).

» Analysis of LIGO data for gravitational waves from binary neutron stars, Phys. Rev. D69: 122001 (2004).

» Analysis of first LIGO science data for stochastic gravitational waves, Phys. Rev. D69: 122004 (2004).

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Science

S2 Feb. 14 – Apr. 14, 2003, 59 days» Limits on gravitational-wave emission from selected pulsars using

LIGO data, Phys. Rev. Lett 94: 181103 (2004).» Search for gravitational waves associated with the gamma ray burst

GRB030329 using the LIGO detectors, Phys. Rev. D, Vol. 72, 042002 (2005)

» Search for gravitational waves from galactic and extra-galactic binary neutron stars, gr-qc 0505041 (2005)

» Search for Gravitational Waves from Primordial Black Hole Binary Coalescences in the Galactic Halo, gr-qc 0505042 (2005)

» Upper limits from the LIGO and TAMA detectors on the rate of gravitational-wave bursts, gr-qc 0507081

» Upper limits on gravitational wave bursts in LIGO’s second science run, gr-qc 0505029 (2005)

S3: October 31, 2003 – January 9, 2004, 70 days S4: February 2, 2005 – March 23, 2005, 50 days

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S5 goal:» one year’s data of coincident operation at the science goal

sensitivity Current Plan (LSC meeting in August)

» Staggered start to S5» L1 was expected to start with S5 on Oct 21» Expect Hurricane related delays:

– LLO is intact, up, and running – No Hotels for visiting scientists and local stuff has some

problems at their homes (power outages, flooding, school closings, etc.)

» H2 start Nov 4» H1 schedule still uncertain—recovery from Test Mass

replacement Performance goals for S5

» H1, L1 over 10 Mpc inspiral range, H2 over 5 Mpc» Overall “Science content” ~ 100 times S4

S5-Run

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Duty cycle

Run S2 S3 S4S5 Target(proposed)

SRDgoal

L1 37% 22% 75% 85% 90%

H1 74% 69% 81% 85% 90%

H2 58% 63% 81% 85% 90%

3-way 22% 16% 57% 70% 75%

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101

102

103

10-20

10-19

10-18

10-17

10-16

10-15

10-14

Frequency [Hz]

Dis

pla

cem

ent

[m/ H

z]H1: 9.8 Mpc, Aug 15 2005 00:58:00 UTC DARM

MICH

PRC

Oscillator

OpticalLevers

WFS

OSEM

Seismic

ETM

ITM

BS

SusTherm

IntTherm

Shot

Dark

Intensity

Frequency

Total

SRD

Latest news from H1:• Achieved 11.6Mpc range!• Runs now routinely above 10MPc!

Peter Saulson 09/04/05

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LIGO Science CollaborationA family photo