LIGO Document E1300513-v1
- L1 SUS PR2 Acceptance Documentation
For General Acceptance Documentation common for all HSTS refer to
https://dcc.ligo.org/LIGO-E1201040 aLIGO SUS HSTS Acceptance Documentation.
August 1st 2013 - Calum Torrie signed on behalf of committee. All looks in good shape. Item in green to be based along in committee report as something to look into as low / medium priority. Calum will also add to Bugzilla list. CIT.
Punchlist items and their resolution will be tracked in T1400181. They will not be updated on this Acceptance Document filecard.
- 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:
https://dcc.ligo.org/LIGO-D0900524 AdvLIGO SUS HAM3-L1, XYZ Local CS for HSTS (PR2) Sub-Assy
D09000524 confirmed present and includes red-lines for as built. Jeff K also confirms co-ordinate definition present.
ICS Assembly #:
- ICS Assembly Load:
This filecard serves as the acceptance document for L1-PR2.
For common material for all HSTS suspensions, see
Confirmed present. No action for now.
The electronics for L1 SUS PR2 can be found in the racks
- Calibrated, M1toM1 Transfer Functions (DAMPING OFF): https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=6266
- Calibrated, M1toM1 Transfer Functions (DAMPING ON): https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=6266
- Calibrated, M2toM2 Transfer Functions (DAMPING OFF): https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=7247
- Calibrated, M3toM3 Transfer Functions (DAMPING OFF): https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=7247
ACTION - CONFIRMED PRESENT and GOOD!
Kissel: All three stages of transfer functions show a change of slope in magnitude, a "turn up," at the highest frequencies shown, typically above 10 [Hz]. We (the suspensions crew) have convinced ourselves that this is a measurement artifact -- an electronic cross-coupling between then OSEM sensor and coil actuator somewhere along the cabling system, and therefore is independent of the dynamics of the suspension. The things that have convinced us:
- The coupling feature has been found in every degree of freedom, at every stage, of every suspension, at every stage of testing, starting at some frequency. Indicating it is something fundamental to the OSEM sensor/actuator chain
- Using the sensors alone, measuring residual seismic noise, we do not see any evidence that the passive isolation is not working as designed. (HOWEVER -- we have not yet had an interferometer sensitive enough to measure the residual sensor noise at frequencies above 10 [Hz]...)
- We have measured the top stage of a BSFM with the suspension locked vs. unlocked, and found this feature still present.
For the lower stages, it is of little concern, because we only use the actuators for global control. For the top stage it is still of some concern, because we use the BOSEM sensors for local control. Yes, we roll off control as fast as we can above the last resonance, but if this feature continues to roll up as f, it can defeat even the best design.
- Calibrated OSEM Sensor ASDs, All Stages (DAMPING OFF): https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=6266
- Calibrated OSEM Sensor ASDs, All Stages (DAMPING ON): https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=6266
WE LOOKED AT DURING MEETING. CALLED PASSED. JEFF K TO ADD NOTE. COMMITTEE WILL REPORT UP.
- B&K Hammer Cage Resonance Transfer Functions: https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=3100
TEAM REVIEWED and PASSED
- Coil Driver Noise: https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=4751
- Coil Driver Response in all states: https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=4495
Confirmed present. Repeat of MC2. Confirmed doing one per flavor of suspension.
- 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.
Repeat of MC2. Confirmed doing one per flavor of suspension.
PASSED. GENERAL SO NOT SPECIFIC FOR EACH ONE!
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 L1 MC2, see links above.
See also reviewer comments on MC2 acceptance page at E1201042
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 https://dcc.ligo.org/LIGO-E1200343
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).
III. General notes and action items:
- 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.
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