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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
== Upgrade of the 40m ==
 * '''[[/Overview]]'''
 * '''Upgrade items & Preparation status'''
  * [[/Configuration]]
   * [[Upgrade 09/Optical Layout|Optical Layout]]
   * [[Upgrade 09/GreenLock|Green Locking]]
  * [[/Optics]]
   * [[Optics Cleaning|Optics Cleaning Plan (Dec 2009)]]
   * [[Upgrade 09/MMT09|New Input Mode Matching]]
  * Mechanics
   * [[/Suspensions]]''' '''
  * Electronics
   * [[Upgrade 09/RF System|RF System]]
   * [[Upgrade 09/Multi Resonant EOM|Multi Resonant EOM]]
  * [[/CDS]]
  * [[Upgrade 09/Purchase List|Purchase List]]
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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. == TAC (Technical Advisory Comittee) meetings ==
 * [[TACs|TAC meetings]]
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People should feel free to add comments -

== 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

TAC (Technical Advisory Comittee) meetings

Upgrade documents

Upgrade_09 (last edited 2012-01-03 23:02:41 by localhost)