Harald Lück for the GEO600 Comissioning team 1 ILIAS Meeting, Palma, Oct. 2005

Title

GEO 600Commissioning Status

Based on a talk of Stefan Hild for the WG1 meeting in Perugia

Max-Planck-Institut für Gravitationsphysik(Albert-Einstein-Institut)

Harald Lück for the GEO600 Comissioning team ILIAS meeting Palma, Oct. 2005

Harald Lück for the GEO600 Comissioning team 2 ILIAS Meeting, Palma, Oct. 2005

GEO 600 layout

1.5-2 kW

0.09

Harald Lück for the GEO600 Comissioning team 3 ILIAS Meeting, Palma, Oct. 2005

Tuning signal recycling to 300 Hz

Better knowledge of IFO parameters:

more accurate parameter predictions from simulations

downtuning to 200 Hz realized

Fixed instability of MI auto-alignment by setting up a new telescope for DWS.

We will stay at 330 Hz !

Harald Lück for the GEO600 Comissioning team 4 ILIAS Meeting, Palma, Oct. 2005

GEO 600 design sensitivity

Harald Lück for the GEO600 Comissioning team 5 ILIAS Meeting, Palma, Oct. 2005

RF setup

OLD setup

New setup:

• Using a less noisy splitter(0/90°)

• Using a cable as phaseshifter

NEW setup

Old setup:

• Dominated by phase noise in the LO path (phaseshifter and splitter(0/90°)

• Due to this noise Q was mixed into P quadrature.

Harald Lück for the GEO600 Comissioning team 6 ILIAS Meeting, Palma, Oct. 2005

Shot noise

Green line is the shot noise level calculated from the DC current of the photodiode.

We are within a factor sqrt(2) shot noise limited above 1kHz !

Harald Lück for the GEO600 Comissioning team 7 ILIAS Meeting, Palma, Oct. 2005

Next step in RF setup (next week)

Proposed by Rana and others

GOALS: • Using only high quality hardware • Guaranteeing high RF levels in all components

Harald Lück for the GEO600 Comissioning team 8 ILIAS Meeting, Palma, Oct. 2005

Noise projections 21st of july

Harald Lück for the GEO600 Comissioning team 9 ILIAS Meeting, Palma, Oct. 2005

Noise in the SR-long loop

Noise in the detection band is entirely limited by front-end-noise (shot noise from the detector).Limits sensitivity from 100 to 500 Hz

PROBLEM

• Large locking range• OLG of 10^6 at 0.1 Hz• No feedback noise above100 Hz

Requirements

1. Servo has a locking mode and a running mode2. Lowering UGF to get less gain in detection band3. Using lowpass filter with very steep roll off above UGF

(implemeted digitally using a dSPACE system)

Solution

Harald Lück for the GEO600 Comissioning team 10 ILIAS Meeting, Palma, Oct. 2005

Analog SR electronics

Red = acq amp, green = acq phaDark blue = run amp, brown = run phaseLight blue = run2 amp, pink = run2 pha

Harald Lück for the GEO600 Comissioning team 11 ILIAS Meeting, Palma, Oct. 2005

Signal Recycling digital

Phase @18 Hz = -147 deg

Harald Lück for the GEO600 Comissioning team 12 ILIAS Meeting, Palma, Oct. 2005

SR feedback: analog vs. digital

Harald Lück for the GEO600 Comissioning team 13 ILIAS Meeting, Palma, Oct. 2005

Sensitivity improvement July to August

High frequency improvements: reduction of RF phase noiseLow frequency improvements: reduction of Signal recycling feedback noise

Harald Lück for the GEO600 Comissioning team 14 ILIAS Meeting, Palma, Oct. 2005

PR-bench

Historically grown layout of PR-bench not optimal !

• beam clipping• too many

transmissive optical components

• too many polarizing components

• acoustic coupling

Goal:Shorten and simplify the HPD path

Harald Lück for the GEO600 Comissioning team 15 ILIAS Meeting, Palma, Oct. 2005

Sensitivity after PR bench work

Removed resonance structures between 100 and 200 Hz.

Harald Lück for the GEO600 Comissioning team 16 ILIAS Meeting, Palma, Oct. 2005

Noise projections 4th of August

Harald Lück for the GEO600 Comissioning team 17 ILIAS Meeting, Palma, Oct. 2005

Michelson length control

< 0.1Hz

Harald Lück for the GEO600 Comissioning team 18 ILIAS Meeting, Palma, Oct. 2005

< 10 Hz

< 0.1Hz

Michelson length control

Reaction Pendulum:

3 coil-magnet actuators at intermediate mass, range ~ 100µm

Harald Lück for the GEO600 Comissioning team 19 ILIAS Meeting, Palma, Oct. 2005

< 10 Hz

> 10 Hz

< 0.1Hz

Michelson length control

Reaction Pendulum:

3 coil-magnet actuators at intermediate mass, range ~ 100µm

Electrostatic actuation on test mass bias 630V, range 0-900V= 3.5µm

Harald Lück for the GEO600 Comissioning team 20 ILIAS Meeting, Palma, Oct. 2005

Using ESD as actuator

• Force is proportional to square of applied voltage.

• high voltages are needed

• for bipolar actuation a bias voltage needs to be applied

Noise is introduced:

• loop electronics

• sqrt circuits

• intrinsic HV amplifier noise

Harald Lück for the GEO600 Comissioning team 21 ILIAS Meeting, Palma, Oct. 2005

Sqrt circuits in MI loop

ESD: F U^2

Sqrt circuits are necessary to give full linear force range for acquisition.

Drawback: sqrt circuits are noisy 1µV/sqrt(Hz)(=100µV/sqrt(Hz) @ ESD)

Harald Lück for the GEO600 Comissioning team 22 ILIAS Meeting, Palma, Oct. 2005

ESD: F U^2

Sqrt circuits are necessary to give full linear force range for acquisition.

Drawback: sqrt circuits are noisy 1µV/sqrt(Hz)(=100µV/sqrt(Hz) @ ESD)

Bypassing sqrt circuits after lock is acquired.

Sqrt circuits in MI loop

Harald Lück for the GEO600 Comissioning team 23 ILIAS Meeting, Palma, Oct. 2005

Noise in MI loop

HVA noise = 100nV/sqrt(Hz) (=10µV/sqrt(Hz) @ ESD)

HV-amplifier noise can be reduced by decreasing bias voltage or active noise suppression.

Suppressing noise introduced by loop electronics needs whitening

Harald Lück for the GEO600 Comissioning team 24 ILIAS Meeting, Palma, Oct. 2005

MI loop whitening / dewhitening

dewhiten

dewhiten

dewhiten

Whiten

Whitening right after mixer:zero 3.5 Hzpole 35 Hz

Dewhitening for both split passes

Passive dewhit-ening done in HV path (0-1kV)

Harald Lück for the GEO600 Comissioning team 25 ILIAS Meeting, Palma, Oct. 2005

Sensitivity after fixing noise from MI loop

Harald Lück for the GEO600 Comissioning team 26 ILIAS Meeting, Palma, Oct. 2005

Noise Projections 6th of October: Excess noise @ 200Hz

Harald Lück for the GEO600 Comissioning team 27 ILIAS Meeting, Palma, Oct. 2005

Current sensitivity vs. Design sensitivity

102

103

10-24

10-23

10-22

10-21

10-20

10-19

10-18

10-17

Freq. [Hz]

ASD

[h/ H

z]GEO600 Theoretical Noise Budget

SeismicSuspension TNSubstrate TNCoating TNThermorefractiveShot 350HzTotalShot Sept 1 h(t) Sept 1

Harald Lück for the GEO600 Comissioning team 28 ILIAS Meeting, Palma, Oct. 2005

Laser Improvements

• Exchanged master laser and slave laser pump diodes for new ones (13.3W from Laser)

• Improved optical path

• Cleaned components on laser bench

→ max. 9.2 W @ MC1

Harald Lück for the GEO600 Comissioning team 29 ILIAS Meeting, Palma, Oct. 2005

Burst events; Start-of-the-second glitches

Harald Lück for the GEO600 Comissioning team 30 ILIAS Meeting, Palma, Oct. 2005

Start-of-the-second glitches: A cal. issue

Harald Lück for the GEO600 Comissioning team 31 ILIAS Meeting, Palma, Oct. 2005

New MI longitudinal loop: reduce longitudinal dark fringe deviations

Old

NewMuch more gain @ low f

Overall gain

Overall gain

Harald Lück for the GEO600 Comissioning team 32 ILIAS Meeting, Palma, Oct. 2005

Low Frequency EP Reduction

10-1

100

101

102

103

104

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

Frequency (Hz)

Am

plitu

de (

Vrm

s /

Hz1/

2 )

nfft/fs = 10.00 : navs = 30 : enbw = 0.15 : nsecs = 300

G1:LSC_MID_EP-P_HPfs = 16384 : 2005-09-26 09:08:28

Optional:

Digital IM Feedback

= analog + res. @ 2.5Hz

Harald Lück for the GEO600 Comissioning team 33 ILIAS Meeting, Palma, Oct. 2005

MI AA digital (dSpace) servo 14th Sept.

Digital

Analog

Added res. gain stages

Harald Lück for the GEO600 Comissioning team 34 ILIAS Meeting, Palma, Oct. 2005

MI AA digital (dSpace) servo 8th Oct.

Tilt (Pitch) Rotation (Yaw)

Digital filter TFs contain resonant gain stages for suspension resonances

Harald Lück for the GEO600 Comissioning team 35 ILIAS Meeting, Palma, Oct. 2005

Reducing Noise in MI AA Loop 19th Oct.

• Optimization of gain distribution in MI AA loop reduced FB noise

Camera dark noise

BeforeAfter

BeforeAfter

Feedback noise

BeforeAfter

BeforeAfter

Rotation (Yaw) Tilt (Pitch)

Harald Lück for the GEO600 Comissioning team 36 ILIAS Meeting, Palma, Oct. 2005

Stationarity / GaussianityL

og(N

)Histograms of BLRMS

Harald Lück for the GEO600 Comissioning team 37 ILIAS Meeting, Palma, Oct. 2005

Current work / next steps

• Non stationary noise (already partly? cured)

• Decrease low frequency EP deviations for most loops, i.e. increase gain (partly done)

• Improve RF set-up

• Enhance to full input power

• Join S5. First in overnight/weekend mode– When close to design sensitivity join in 24/7 mode

Harald Lück for the GEO600 Comissioning team 38 ILIAS Meeting, Palma, Oct. 2005

Sensitivity improvement of GEO

102

103

10-21

10-20

10-19

10-18

10-17

Frequency [Hz]

h(t

) [H

z-1/2

]

Jan 02

Aug 02 (S1)

Jan 04 (S3)

Sept 05

Feb 05 (S4)

Aug 04

Harald Lück for the GEO600 Comissioning team 39 ILIAS Meeting, Palma, Oct. 2005

¿Preguntas? Translation Alta Vista Babelfish

Sunset in Ruthe