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The Virgo+ shutdown

The Virgo+ shutdown. Performances before V+ shutdown. Virgo progress. Virgo sensitivity: May 2008. Spikes: relaxation of magnet waterglass glueing. Recent upgrades. The cryotrap. Brewster window (SR-DT) introduces noise Several attempts to mitigate scattered light

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The Virgo+ shutdown

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  1. The Virgo+ shutdown

  2. Performances before V+ shutdown

  3. Virgo progress

  4. Virgo sensitivity: May 2008 Spikes: relaxation of magnet waterglass glueing

  5. Recent upgrades

  6. The cryotrap • Brewster window (SR-DT) introduces noise • Several attempts to mitigate scattered light • Baffles in detection and SR towers, near the Brewster, … • Final decision: remove it • Avoid spoiling of central area vacuum from detection tower • => cryotrap • Cryotrap installation shutdown 10 days • Interferometer locked immediately afterwards • Nice success of the vacuum group Signal recycling To ext. detection bench Detection tower

  7. Cryotrap functioning • Duration of functioning 3 days • Refilling takes 1 hour • Project of increasing functioning time to >= 1 week • Before the next science run

  8. DAQ room air conditioning upgrade • Air conditioning systems affects the Virgo sensitivity • DAQ room is just in front of the detection lab • the noise of its (oldest) air conditioning system has been found directly in the dark fringe DAQ room (+CE hall) North End AC AC ON AC OFF CleanRooms AC  Laser lab Central hall AC Water pump of CE

  9. DAQ room air conditioning upgrade DT SR DT lab Acoustic isolation of the DAQ => reduce noise in central area New AC system outside DAQ Microphone sees a noise reduction wrt. to the previous situation. AC before after AC off Hz

  10. Thermal compensation system • Thermal lensing in the input mirrors has had a strong impact on commissioning • Complicated locking procedure for surviving thermal transient • Bistabilities arise during transition • Be sure to catch the good state for continuing locking • We want to go from 8 to 25 Watt in Virgo+ • Much higher power => no hope to survive thermal deformations • => Thermal compensation system needed • CO2 laser ring system designed and realized by Roma Tor Vergata group with support by EGO

  11. TCS layout Chiller Electronics

  12. TCS optical layout

  13. TCS in-vacuum optics In vacuum steering mirrors needed

  14. TCS in-vacuum optics In vacuum steering mirrors needed

  15. TCS status • CO2 laser problems • One of the two lasers arrived broken from the company (Access Laser) • Sent back but delivered again out of order • Probably an undetected CO2 gas leakage • Sent back to the company a second time • WI TCS commissioning started • Still many things to be learned, but: • First encouraging results (see Enrico’s talk) • To be done • Power stabilization to be realized in the next months • Central spot needed for reducing thermal transient time? • Continue commissioning as soon as interferometer available again

  16. The Eddy current issue • Increase of thermal noise due to Eddy current dissipation • Too strong SmCb magnets + aluminum reference mass • Noise level <-> Virgo sensitivity: subject to discussions • Magnetic noise coupling from external perturbations • Solution 1 • Ferromagnetic hats proposed for reducing magnetic field • Solution 2 (chosen) • In-place substitution of magnets with smaller ones • Endoscopic procedure with tube, vacuum aspiration of dust etc. • Worked well, except re-gluing of one FS support with “water glass” • => glitches in WI? • NE magnet substitution => • No more Eddy current problems expected in Virgo+

  17. Upgrades during the Virgo+ shutdown

  18. Virgo+ shutdown • Was scheduled for 3rd of June • May 9th incident => shutdown anticipated by 3 weeks • Required rearrangement of infrastructure works due to need of clean rooms • Shutdown: Virgo+ packages • High power laser + corresponding optics • New control and DAQ electronics • Environmental noise mitigation • NE tower recovery

  19. Laser amplifier I • Amplifies 20 W slave laser => 50 (up to 65) W • Integration started 22/05 Old Virgo layout This part has been removed

  20. Laser amplifier II • Much denser optical setup

  21. Pre Mode Cleaner • PMC was designed for filtering of technical laser noise at 6 MHz • Also guarantees a good beam shape

  22. PMC mechanical scheme Vacuum tank 74mm Mirror glued on piezo actuator Zerodur Front mirrors Spider 126mm mirror Corundum ½ sphere Glued mirrors piezo Brewster window 0.35m • Triangular zerodur cavity • * avoid thermal control - low mechanical Q • Controlled by 1 piezo • * Corundum half sphere glued on piezo • * Pushing a “telescope spider” shaped support • * 6x12 diam. mirror, glued on spider • -> Avoid piezo bending transfer to mirror displacement) • ( simulation by F. Richard) • Vacuum tank, Brewster window

  23. PMC mounting PMC tank PMC on its cradle

  24. External injection bench To ITF • Super-polished optics for avoiding scattered light • Polished by General Optics / coated by LMA, Lyon From laser

  25. Suspended injection bench • Faraday isolation factor will go down with higher power (therm. lens) • => insertion of remotely controllable waveplate for isolation improvement • + compensation plate, if necessary

  26. Input mode cleaner mirror • Old MC mirror was not good • Too light (80x30 mm) • radiation pressure forces • reference mass suspension <-> coil cables • Bad optical quality; • backscattering in opposite direction

  27. New MC payload • New MC mirror payload • Heavier (1.4 kg) • Better optical quality

  28. Control and DAQ Electronics package Big change in electronics during shutdown Obsolete components Better design (differential ADC inputs,…), lower noise Better performance (global control speed, more filters,…) 1. DAQ electronics (LAPP, Annecy) Real time PCs, interconnected with Mux/Demux boards New ADCs, timing system Installation ongoing; to be finished during shutdown 2. New DSP for suspension control (Pisa) Much more powerful (6 DSP on one chip) Step-by-step installation, in parallel with old system Install new DAQ system check that new data is same as old one Install new global control system check that new Gc output is the same as old one Check compatibility of new system with suspension control (DSP) => when all tests positive, go to new system

  29. Suspension control DAQ Room Mode Cleaner Build. IB Platform ADC PSD RT PC DACs DSP Sc RIO-B RIO-A DSP Sa Camera ADCs Mx/Dx ADC PSD ADCs DSP Sc RIO-B DACs DSP Sa RIO-A Camera RT PC Mx/Mx Mx/Dx PR/BS/NI/WI/ SR Mx/Dx ADC PSD ADCs RT PC DACs DSP Sc RIO-B RIO-A DSP Sa Camera Mx/Dx Laser Lab OB ADC PSD RT PC DACs DSP Sc RIO-B RIO-A DSP Sa Camera ADCs Mx/Dx Detection Lab NE/WE Terminal Building ADC PSD RT PC ADCs RIO-B RIO-A DSP Sa DSP Sc Camera DACs Mx/Dx Computing Room STAC/Council June 2008 29

  30. ISYS control DAQ Room Mode Cleaner Build. IB Platform BMS ADC PSD ADC Coil RT PC DACs DSP Sc RIO-B RIO-A DSP Sa Camera ADCs Mx/Dx RIO-A ADC Coil ADC PSD ADCs DSP Sc RIO-B DACs DSP Sa RIO-A Camera RT PC DAC DSP Bc Mx/Dx PR/BS/NI/WI/ SR ADC Env,Qt Mx/Dx Laser Lab OB ADC SSFS,IMC RIO-A Lo:Vb:Qa ADC RFC,BMS DAC Mx/Dx Detection Lab NE/WE Terminal Building Mx/Dx Computing Room RT PC DET RT PC ISYS RT PC CaRT STAC/Council June 2008 30

  31. ITF control DAQ Room Mode Cleaner Build. IB Platform BMS ADC PSD ADC Coil RT PC DACs DSP Sc RIO-B RIO-A DSP Sa Camera ADCs Mx/Dx RIO-A ADC Coil ADC PSD ADCs DSP Sc RIO-B DACs DSP Sa RIO-A Camera RT PC DAC DSP Bc Mx/Dx PR/BS/NI/WI/ SR ADC Env,Qt Mx/Dx ADC PSD ADC Coil ADCs RT PC DACs DSP Sc RIO-B RIO-A DSP Sa Camera Mx/Dx ADC Q5 Laser Lab Alignment ADC Q2 ADC B2,B2_3f ADC Q1p ADC RFC,BMS OB RIO-A Lo:Vb:Qa ADC SSFS,IMC DAC RIO-A Lo:Vb:Qa Mx/Dx Mx/Dx ADC PSD ADC Coil RT PC DACs DSP Sc RIO-B RIO-A DSP Sa Camera ADCs Mx/Dx 2 DACs Mx/Dx Detection Lab NE/WE Terminal Building ADC PSD ADC Coil RT PC ADCs RIO-B RIO-A DSP Sa DSP Sc Camera DACs Mx/Dx Mx/Dx ADC Ph.Cam ADC SFP,TCS ADC Pi ADC Mc RIO-B1*,B5 Pos RIO-A Lo:Vb:Qa ADC B1,B1p ADC B1_2f,B1s ADC B5,B5_2f 4 Cameras 4 DACs Mx/Dx Computing Room RT PC DET Calibration RT PC ISYS RT PC CaRT RT PC zITF RT PC tx,tyITF RIO-B B7Pos RIO-A Lo:Vb:Qa ADC B7 ADC Q7 2 Cameras RIO-A 2 DACs DAC Mx/Dx ADC STAC/Council June 2008 31

  32. Environmental noise reduction The reduction of the environmental noises is a “never ending story” During the shutdown a series of tests and actions is going on The major ones are the displacement of the laser lab electronics to a new “EE room” the displacement of the detection photodiodes under vacuum

  33. The EE (electronics equipment) room • A part of the laser lab electronics racks will go to its own room • Acoustically isolated • Laser chiller has a separate room EE room MC Laser lab

  34. Photodiodes under vacuum Putting photodiodes under vacuum for reducing environmental noise coupling through scattered light • Photodiodes, the pre-amplifier, the motors and supports will go under two vacuum proof boxes, air filled (electronics cooling) 34

  35. The boxes Boxes are in steel (3mm thick) and their behavior in vacuum has been FEM studied at LAPP. The additional weight should be compliant with a minor retuning of the suspension

  36. Summary – upgrades already made • Cryotrap installation • For getting rid of “Radio Brewster” • DAQ room airconditioning improvement • For reducing environmental noise • Thermal compensation system • Installed, but laser broken; to be commissioned • Magnet weakening • Results to be seen after restart

  37. Summary - Virgo+ shutdown upgrades • Injection system optics • Laser amplifier – installed, long term observation going on • Pre-Mode cleaner – installed, locked • Low scattering optics on ext. bench - optics delivered • Faraday isolation, remote tuning - to be installed • Mode cleaner curved mirror with marionette+reference mass • Installed: MC has been relocked • Laser lab electronics equipment room • Infrastructure works finished; electronics to be migrated • Photodiodes under vacuum • To be installed after whole ITF has been relocked again • New DAQ electronics • Ongoing; to be finished before relock • New suspension electronics • To be done in a second time

  38. End

  39. Cryotrap: Residual gas analysis Part. pressure (mbar) RGA installed on trap (SR side) Before (blue) and after (black) the DT opening, and compared to DT (blue) air water H2 Contamination 1E-10 mbar

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