LIGO Document E1201042-v2

L1 SUS MC2 Acceptance Document

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Document type:
E - Engineering documents
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L1 SUS MC2 Acceptance Documentation

For General Acceptance Documentation common for all HSTS refer to aLIGO SUS HSTS Acceptance Documentation.

7th June - Signature added by Calum Torrie on behalf of committee. Good job.

Punchlist items and their resolution will be tracked in T1400181. They will not be updated on this Acceptance Document filecard.

Files in Document:
Notes and Changes:
I. Committee (* indicates review chair)
Rich Abbott, Alastair Heptonstall, Calum Torrie*, Jeff Lewis, Fabrice Matichard, Celine Ramet.

II. Documents for Review (against list from M1100282)
Top Assembly Name: AdvLIGO SUS HAM3-L1, XYZ Local CS for HSTS (MC2) Sub-Assy
ACTION - Calum / Jeff L. to review and comment - CLOSED
Reply from Jeff L.:
The document looks fine. Waiting reply from email question to Matt H if any further changes need to be made to capture any discrepancies which might have arisen during installation. This can pass to INS Acceptance Review. Calum

ICS Assembly #:
- ICS Assembly Load:
Confirmed present. No action for now. - CLOSED

Acceptance document:
This filecard serves as the acceptance document for L1-MC2.
For common material for all HSTS suspensions, see
Confirmed present. No action for now. - CLOSED

ICS inventory
ACTION - All to 'find' an item and comment on success and structure. This has been done by Jeff K. - CLOSED

The electronics for L1 SUS MC2 can be found in the racks
ACTION - Rich, do you have anything for here (for Norna)? - Rich to re-take this action.
Rich - Looked at rack diagrams, provided what I see is current and accurate, then all looks well. Should I be looking for a similar diagram for H1? NO - CLOSED

Test results:
- Calibrated, M1toM1 Transfer Functions (DAMPING OFF):
- Calibrated, M1toM1 Transfer Functions (DAMPING ON):
ACTION - Celine to review response to her comments by Stuart. Sensor noice added and meets requirements. Celine happy. - CLOSED

- Calibrated, M2toM2 Transfer Functions (DAMPING OFF):

- Calibrated, M3toM3 Transfer Functions (DAMPING OFF):

- Calibrated OSEM Sensor ASDs, All Stages (DAMPING OFF):
- Calibrated OSEM Sensor ASDs, All Stages (DAMPING ON):
ACTION - Fabrice comment - action with Jeff K.
Reply from Fabrice:
- What is the acceptance criteria on the Q? (i.e. what value of viscous damping ratio would ultimately compromise the high frequency passive isolation) Content for now.
- Does the Q has been extracted from the transfer functions to compare with acceptance criteria? ( a fit can be used if the resonance is not sufficiently resolved)
- What is the variability from one unit to another, and what causes the variability?
ACTION - Very complete. All looks well. Fabrice - CLOSED!

- B&K Hammer Cage Resonance Transfer Functions:
ACTION - Very complete. All looks well. Calum - CLOSED!

- Coil Driver Noise:
- Coil Driver Response in all states:
ACTION - I reviewed the entries and other than the remarkable thoroughness. Rich / Peter / Vern looking at book keeping of the test data associated with the electronics. Rich Abbott
Here's some notes/action items on a review of coil driver test results in general:
Notes on Suspension Data meeting:

1. Document/memo that states each change (drivers, monitors, state of stability capacitor addition, etc.).
2. Test criteria for passing or failing each parameters.
3. Mine the existing spreadsheet data for histogram noise at 10Hz, plus pole zero locations.
4. Vern to find spreadsheet of data LLO and LHO if possible.
5. Document to show noise/frequency response simulation results for each variant of coil driver.
6. Question of top driver current range. Starting with a noise model, increase the gain to provide 200mA peak current. Modify one chassis like that as a verification of principle.
7. Do allowable current noise calculation for each of the coil driver stages.

While above allows data to be organized for accepting MC2 this is closed. Rich A.

- Violin Mode Frequencies and Q
Measured violin mode Qs are used to estimate wire losses (structural and thermo-elastic) and hence expected thermal noise at lower frequencies. Results tie up well with our model and provide evidence that double prism technique appears to be doing its job.
Reply from Alastair:
The frequency and violin mode measurements on MC2 are extremely well documented in both the alog and in a write-up by Mark Barton T1200418.
I have to say that I would agree fully with Mark's observations - the violin mode frequencies tie up, and the Q measurements fit with the standard model of structural + thermoelastic damping.
Suggestion from Jeff K.:
Evaluate Q once for each suspension type. Not required. Could / should be done as available for one of each type of SUS. Pass on / up.

Note added 5th Sept 2014 for clarification (NAR/CIT)
Predicted violin mode frequencies and Qs for all types of suspensions are given in T1300876. These can be compared to measured values.
Measuring Qs is not a requirement for SUS acceptance.
For Installation acceptance it has been agreed that we should measure Qs once for each major suspension type.
For HSTS, we measured violin mode Qs on this suspension, namely L1 MC2.
Note that double prism technique is also used for the HLTS and BS.

Channel/Signal List and Calibrations
For latest measurements of OSEM Sensor's Open Light Current, See
Otherwise calibrations are assumed to be as shown in HSTS Control Design Description,
with a roughly 20% uncertainty (determined by the worst discrepancy seen between modeled and measured transfer functions across all DOFs and many HSTSs). The following channels are calibrated into [um] or [urad]:

L1:SUS-MC2_M1_ISIWIT_{L,T,V,R,P,Y}_DQ (Susp Point)
L1:SUS-MC2_M1_DAMP_{L,T,V,R,P,Y}_IN1_DQ (Top Mass)
L1:SUS-MC2_M2_WIT_{L,P,Y}_DQ (Middle Mass)
L1:SUS-MC2_M3_WIT_{L,P,Y}_DQ (Optic)

(For coordinate system definition, see

ACTION - Rich, do you have anything for here (for Norna)? Rich has re-taken this task. RICH Happy - CLOSED

III. General notes and action items:
- Jeff K. noted that lower stage transfer function were missing and would be added. DONE JSK 2013-05-29

- Jeff K. will add a link to this file card which captures the S# electronics that were used for MC2 link to rack. DONE, JSK 2013-05-29

- The review team should review E1201040 in detail - unless the SUS Acceptance format changes and E1201040 is no longer the preferred method of presenting this info. TBD.

- Jeff K. will add a list of channels/signals. DONE JSK 2013-05-29
Jeff K - where are they?? ABOVE!! ADDED JSK 2013-06-04

- Stuart A. Power spectra plots now include the expected sensor noise limited performance, as requested, appended to the original aLOG entries above. DONE SMA 2013-05-31

Referenced by:

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