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| = Upgrade of the 40m = This page describes the big topics in the Upgrade of the 40m interferometer from Mk III to Mk IV. |
## page was renamed from Upgrade 08 |
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| The main point is to make it more like the AdvLIGO interferometer. There are not too many details on this page so as to not reduce clarity. | == Upgrade of the 40m == |
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| People should feel free to add comments - | * '''[[/Overview|Overview]]''' * '''Upgrade items & Preparation status''' * [[/Configuration]] * [[/Optics]] * [[/CDS]] * [[/Suspensions]] * [[/Optical Layout]] * [[/PDs]] * [[/GreenLock]] * [[/Purchase List]] |
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| == Arm Cavity Finesse == We will change the transmission of the ITMs from 0.5% to 1.4% to match the new AdvLIGO design. We will also replace the MOS (with 1.25 kg masses) with SOSs. This is to increase the effect of radiation pressure. 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. == 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. == 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. Should we get new PR and SR or use what we have? (curvature, reflectivity). Maybe we should match the AdvLIGO Gouy phases. We will make the tip/tilts so that we can have a POP signal. We also keep POX & POY. == 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. == 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. == 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. == 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. |
== Upgrade documents == * [https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=231 Upgrade Doc in DCC] * [http://lhocds.ligo-wa.caltech.edu:8000/advligo/ISC_Modeling_Software/CVSinstructions?highlight=(CVS) "MIT CVS repository instructions for accessing AdvLIGO modeling"] * 40m upgarde plan scrutiny Ver. 9/29/2009 [attachment:upgrade09_090929.pdf [PDF]][attachment:upgrade09_090929.graffle [OmniGraffle]] |
Upgrade of the 40m
Upgrade items & Preparation status
Upgrade documents
[https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=231 Upgrade Doc in DCC]
[http://lhocds.ligo-wa.caltech.edu:8000/advligo/ISC_Modeling_Software/CVSinstructions?highlight=(CVS) "MIT CVS repository instructions for accessing AdvLIGO modeling"]
40m upgarde plan scrutiny Ver. 9/29/2009 [attachment:upgrade09_090929.pdf [PDF]][attachment:upgrade09_090929.graffle [OmniGraffle]]