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| ## page was renamed from Upgrade 08/Overview == Arm Cavity Finesse == We will change the transmission of the ITMs from 0.5% to 1.4% to match the new AdvLIGO design. |
<<TableOfContents([2])>> ----- = Purpose of the upgrade = ----- == To demonstrate AdvLIGO interferometer technologies == === ►Prototyping of AdvLIGO LSC === * '''Lock acquisition''' * "Prove AdvLIGO LSC actually works" * '''Green laser locking''' * "Realize lock of the arms independently from the main beam" * "Achieve semi-deterministic lock & smooth handing off" * '''Noise mechanisms / DC readout''' * "Discover and/or confirm by a model RSE specific noise couplings" |
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| We will also replace the MOS (with 1.25 kg masses) with SOSs. This is to increase the effect of radiation pressure. | === ►Tuned / Detuned RSE comparison === * "Address advantage and disadv. of the tuned/detuned configuration" * "Demonstrate smooth transition" |
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| We will not fine-tune the coatings of the ITMs for cool dichroic properties unless some coating place gives us a <4 month lead time. | === ►RGC based digital control system === * "Demonstrate complicated LSC code on the connected multiple systems" * "Establish rapid prototyping methods with simulated plants on the processors" |
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| == Modulation Frequencies == We will change the modulation frequencies from f1=33 MHz and f2 = 166 MHz to f1 = 9 MHz and f2 = 45 MHz. We will increase the length of the MC to accomodate this. |
----- == To do anything useful to make the AdvLIGO easier / faster == === ►DC&Dither technologies === * Offset lock and handoffs * AF WFS technique * "Develop and characterize various new useful techniques" |
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| == Recycling Cavities == We will increase the length of the RCs to handle the lower modulation frequency. This will require 2 tip/tilt mirrors per cavity. These will be imperial, eddy current damped versions of the ANU tip/tilt mirrors. |
=== ►Interferometer Diagnosis === * Cavity characterization using aux. laser injection * "Provide a method of precise in-situ characterization of the interferometer" |
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| Should we get new PR and SR or use what we have? (curvature, reflectivity). Maybe we should match the AdvLIGO Gouy phases. | === ►Development / test bench of advanced technologies === * GigE CCD WFS technique * Adaptive noise cancellation * "Demonstrate how it works" * "Understand and improve its limitations" |
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| We will make the tip/tilts so that we can have a POP signal. We also keep POX & POY. | ----- ----- = Major things to be upgraded = ----- == Interferometer design == === ►Interferometer design === * AdvLIGO like optical configuration / sensing scheme * Arm finesse of about 450 * 2 Phase modulations (11MHz & 55MHz), no Mach Zehndar * Longer PRC/SRC => Use of Folding mirror |
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| == Mach Zender == We will not use a Mach Zender. We will use 2-3 EOMs in series or a UF Trimod if it shows up. |
* PR gain decided for carrier, SR gain decided by sensitivity * Small asymmetry, extraction of f2 by a undercoupled SEC => good through put of f2 to the dark port * Use of third harmonic demodulation scheme |
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| == Control System Computers == We will have a big multi-core box to run all of the front ends. It will have fast fiber links to remote ADC/DACs. |
* Links to [Optical Configuration][Power Budget][Optical Layout][PRC/SRC design][Sensing scheme][Lock Acquisition scheme] |
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| == Multi-wavelength Locking == Make wedges and coatings to accomodate multi-color locking if the lead time is reasonable. The beam from the end should not see the corner. |
* Tuned or detuned? * Tuned / offset detuning What should be compared? |
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| == Optical Levers == Make a fiber based OL delivery scheme. Try to also make 40m long OLs by putting turning mirrors into the vacuum system. == Analog Electronics == === Suspensions === No change of the suspension analog electronics. We will have interface cards/connectors to go from new style ADC/DACs into the old analog electronics. === LSC === New RFPDs for the 9 & 45 MHz as well as 3*f1 (27 MHz). Maybe DD as well. == Cameras == We'll have GigE cameras and an all GigE backbone for all CDS connections. |
== Optics == == CDS (Control and Data System) == |
<<TableOfContents: execution failed [Argument "maxdepth" must be an integer value, not "[2]"] (see also the log)>>
Purpose of the upgrade
To demonstrate AdvLIGO interferometer technologies
►Prototyping of AdvLIGO LSC
Lock acquisition
- "Prove AdvLIGO LSC actually works"
Green laser locking
- "Realize lock of the arms independently from the main beam"
"Achieve semi-deterministic lock & smooth handing off"
Noise mechanisms / DC readout
- "Discover and/or confirm by a model RSE specific noise couplings"
►Tuned / Detuned RSE comparison
- "Address advantage and disadv. of the tuned/detuned configuration"
- "Demonstrate smooth transition"
►RGC based digital control system
- "Demonstrate complicated LSC code on the connected multiple systems"
- "Establish rapid prototyping methods with simulated plants on the processors"
To do anything useful to make the AdvLIGO easier / faster
►DC&Dither technologies
- Offset lock and handoffs
- AF WFS technique
- "Develop and characterize various new useful techniques"
►Interferometer Diagnosis
- Cavity characterization using aux. laser injection
- "Provide a method of precise in-situ characterization of the interferometer"
►Development / test bench of advanced technologies
- GigE CCD WFS technique
- Adaptive noise cancellation
- "Demonstrate how it works"
- "Understand and improve its limitations"
Major things to be upgraded
Interferometer design
►Interferometer design
- AdvLIGO like optical configuration / sensing scheme
- Arm finesse of about 450
2 Phase modulations (11MHz & 55MHz), no Mach Zehndar
Longer PRC/SRC => Use of Folding mirror
- PR gain decided for carrier, SR gain decided by sensitivity
Small asymmetry, extraction of f2 by a undercoupled SEC => good through put of f2 to the dark port
- Use of third harmonic demodulation scheme
- Links to [Optical Configuration][Power Budget][Optical Layout][PRC/SRC design][Sensing scheme][Lock Acquisition scheme]
- Tuned or detuned?
- Tuned / offset detuning What should be compared?
Optics