Raab: Searching for Gravitational Waves w/ LIGO

1LIGO-G040286-00-W

Why Has Duty Cycle Been Lower in Livingston

Raab: Searching for Gravitational Waves w/ LIGO

2LIGO-G040286-00-W

Low-F Isolation with the Hydraulic External Pre-Isolator (HEPI)

Adv. LIGO approach, accelerated & adapted for use in initial LIGO

Raab: Searching for Gravitational Waves w/ LIGO

3LIGO-G040286-00-W

HEPI

Raab: Searching for Gravitational Waves w/ LIGO

4LIGO-G040286-00-W

HAM

BSC

Active External Pre-Isolators

Seismic Retrofit at Livingston

Raab: Searching for Gravitational Waves w/ LIGO

5LIGO-G040286-00-W

Installation

Coarse & Fine (PEPI) Actuation Systems

HEPI

Helical Spring(1 of 2)

Vertical Actuator

HorizontalActuator Crossbeam

Pier

Raab: Searching for Gravitational Waves w/ LIGO

6LIGO-G040286-00-W

One-Arm Test of External Pre-Isolation Confirms Performance

Raab: Searching for Gravitational Waves w/ LIGO

7LIGO-G040286-00-W

Thermal Compensation

Over-heat Correction

Inhomogeneous Correction

Under-heat Correction

CO2

Laser

?

ZnSe Viewport Over-heat pattern

Inner radius = 4cm Outer radius =11cm

Cold power recycling cavity is unstable: poor buildup and mode shape for the RF sidebands

ITM thermal lens power of ~0.00003 diopters needed to achieve a stable, mode-matched cavity

intended to be produced by ~25 mW absorbed from 1μm beam

ITM

Raab: Searching for Gravitational Waves w/ LIGO

8LIGO-G040286-00-W

TCS Installation Two CO2 Lasers are

installed on H1 Two more TCS systems

(4 lasers) are being procured/fabricated for H2 and L1

Assembly & Installation will start 6/7

Commissioning expected to be completed ~8/1 on H2 and L1

To ITM HRsurface

Two CO2 Lasers installed on H1