Weekly meeting Cascina 9 Jan 2007 MSC recent activities Weekly meeting Cascina 9 Jan 2007

MSC activities during last month have been focused on 12/6/2018 MSC activities during last month have been focused on Test of new strategies to face the winter (seism,mseism) tests of improved vertical control Improved DSP card logic to use “hybrid” filters (seism-mseism) Development and implementation of new operation interface Development of automated suspension re-centring EM-MSC-090107 wwwwwww

Winter issues: STD scheme and blending used until Dec 2006 ACC LVDT + HP LP cross IP fcrossover = 50 mHz Compromise between: 30 mHz (wind disturbance through ACC) and 70 mHz (mseism disturbance through LVDT) Note: since 2005 we have much larger margin on number of digital filter coefficients in the DSP and speed. EM-MSC-090107

Winter issues: hybrid filters (W2S tuning with no download) mix =1 (mseism) : similar to STD @ 40 mHz + notch improvement + improvement above 50 mHz ACC LVDT + HPm LPm IP HPw LPw mix cross mix =0.5 : similar to the STD @ 50 mHz + notch improvement mix =0 (wind): featured to follow @ 50 mHz + notch improvement + improvement below 50 mHz effect of HPLP featuring EM-MSC-090107

Experience overview (from STD + to anti mseism) mix = 0.5 (close to old STD ID) to mix =1 (sea) majorana - 15:17, Thursday 04 January 2007 EM-MSC-090107

Experience overview (Dec 4th - Jan 4th) mix = 1 versus STD 50 mHz similar mseism (sea) conditions Overall reduction of mseism re-injection Overall improvement shown on zCorr (i.e. smaller longitudinal motion of the mirrors) EM-MSC-090107

Other tests: this week… Comparison between an improved anti-wind (G.Losurdo and the running one), it will be tested. Target: release a hybrid configuration for the run EM-MSC-090107

(Paolo Giovanni Ettore) Development of flexible design and operation Many parallel efforts GIPC (Paolo Giovanni Ettore) Development of flexible design and operation (Paolo Giovanni Ettore) Filter re-design (Matt) No path has been abandoned ! EM-MSC-090107

mseism VS tilt EM-MSC-090107

cavities locked independently mseism (300-600) mHz: relevant LVDTs seismic component in ID, blending must be accurate; => better lowering Acc/Pos cross-over frequency. cavities locked independently (correction signals) As expected Next slide Note: mseism produces excitation of payload pitch and yaw (qx,qz ). Notches implemented to reduce it. 30 mHz crossover N-arm 70 mHz crossover W-arm EM-MSC-090107

wind speed || LVDT_rms increase (observation); Tilt (f< 100 mHz): wind speed || LVDT_rms increase (observation); tilt causes fake acceleration (Losurdo, Passuello, Ruggi); => ID causes LVDT_rms increase through in-loop accel. signal. wind speed susp displacement X crossover f = 30 mHz; Z crossover f = 50 mHz EM-MSC-090107

mandatory: reduction of rms displacement of IP at low frequency. GIPC mandatory: reduction of rms displacement of IP at low frequency. main benefits: wind disturbance rejection, lock acquisition, duty-cycle. Once the ITF is locked, the mirror position, provided by the Global control, can be used instead of Local LVDT. GC (reconstructed z) Tested at step 4 WI,NI fx=30 mHz WE,NE,BS,PR fx= 70 mHz WI,NI Tower frames (LVDT vs ground) EM-MSC-090107 pruggi

BS,PR,NE under GIPC, fx =70 mHz all EM-MSC-090107

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Performance weakness of some features 12/6/2018 MSC “open” issues Development of better operation interfaces to facilitate more flexible tests of strategies and new implementations Performance weakness of some features - visual interface including F7 and V damping (this week design session) x and tz local control damping (this week one shift on this topic) “soft download” facility to allow quiet and repeatable swap between DSP implementations to cope with extreme environmental situations EM-MSC-090107 wwwwwww

Performance weakness of some features 12/6/2018 MSC “open” issues Development of better operation interfaces to facilitate more flexible tests of strategies and new implementations Performance weakness of some features - visual interface including F7 and V damping (this week design session) x and tz local control damping (this week one shift on this topic) “soft download” facility to allow quiet and repeatable swap between DSP implementations to cope with extreme environmental situations EM-MSC-090107 wwwwwww

WSR6 DECISIONS TAKEN BEFORE THE RUN 12/6/2018 DECISIONS TAKEN BEFORE THE RUN Spikes related to V-damp at WE occurred the Thursday night IB V-damp was implemented on Friday morning 50 mHz-peaked seismic bump was present in the afternoon V-damp long susp not tested under all mseismic conditions Operator-level switch for V-damp was not designed yet Signals flags to decide about V-damp ON/OFF not studied yet V-damp OFF for the run EM-MSC-090107 wwwwwww

IB: V-damp Implementation of V-damp for IB suspention EM-MSC-090107 12/6/2018 Implementation of V-damp for IB suspention EM-MSC-090107 wwwwwww

IB: V-damp 12/6/2018 Just before WSR6… EM-MSC-090107 wwwwwww

WE: V-damp Problem of WE V-damp before WSR6 Under investigation 12/6/2018 WE: V-damp Problem of WE V-damp before WSR6 Under investigation EM-MSC-090107 wwwwwww

V-damp to be completed and interfaced with the operation 12/6/2018 Conclusions V-damp to be completed and interfaced with the operation Fight against wind and mseism going on (3 shifs/week rquested): measurements, modeling, tests. Software interfaces to facilitate operator and shifter actions under development Performance checkups and maintenance going on EM-MSC-090107 wwwwwww

F7 F7 damping ty implemented in 6 towers LC and AA filters can with 12/6/2018 F7 damping ty implemented in 6 towers LC and AA filters can with no compensation @ 16 mHz. handle to improve damping performance VS payload motion. other degrees of freedom ? EM-MSC-090107 wwwwwww

Vdamp vertical damping (y) implemented in 6 towers basically the same filter used for horizontal ID (@ 70 mHz). only top sensor used (F0) mseism rms reduction (NS-NS Horizon > 0 last stormy weather..). gain optimization under study short towers ? (this week) EM-MSC-090107

Vdamp vertical damping (y) implemented in 6 towers basically the same filter used for horizontal ID (@ 70 mHz). only top sensor used (F0) mseism rms budget reduction in critical weather conditions (lock during last night storm) short towers ? (next step, probably, urgent) EM-MSC-090107

GIPC Tested using all GC signals (PR,BS,NE,WE) at steps 1, 4, 12 yesterday night data under study > Mandatory issue: reduction of seismic (sea) re-injection > A shift is following EM-MSC-090107

step 11 V-damp ON/OFF: 6 suspensions EM-MSC-090107

step 11 V-damp ON/OFF one-by-one and OFF/ON All No crucial Improvement O-B-O OFF ALL OFF ALL ON No crucial Improvement during OBO Test. Clear Improvement All OFF/ON Relationship with Angular fluctuations EM-MSC-090107

step 11 V-damp ON/OFF one-by-one and OFF/ON All EM-MSC-090107

storm+GIPC step 12 Next improvements and studies A major effort necessary at LF during stormy weather! Note: preliminary version of GIPC And gain mistake Of IP reallocation @ WE. EM-MSC-090107

mseism VS tilt EM-MSC-090107

cavities locked independently mseism (300-600) mHz: relevant LVDTs seismic component in ID, blending must be accurate; => better lowering Acc/Pos cross-over frequency. cavities locked independently (correction signals) As expected Next slide Note: mseism produces excitation of payload pitch and yaw (qx,qz ). Notches implemented to reduce it. 30 mHz crossover N-arm 70 mHz crossover W-arm EM-MSC-090107

wind speed || LVDT_rms increase (observation); Tilt (f< 100 mHz): wind speed || LVDT_rms increase (observation); tilt causes fake acceleration (Losurdo, Passuello, Ruggi); => ID causes LVDT_rms increase through in-loop accel. signal. wind speed susp displacement X crossover f = 30 mHz; Z crossover f = 50 mHz EM-MSC-090107

mandatory: reduction of rms displacement of IP at low frequency. GIPC mandatory: reduction of rms displacement of IP at low frequency. main benefits: wind disturbance rejection, lock acquisition, duty-cycle. Once the ITF is locked, the mirror position, provided by the Global control, can be used instead of Local LVDT. GC (reconstructed z) Tested at step 4 WI,NI fx=30 mHz WE,NE,BS,PR fx= 70 mHz WI,NI Tower frames (LVDT vs ground) EM-MSC-090107

BS,PR,NI under GIPC, fx =70 mHz all EM-MSC-090107