LVC meeting (parallel session)
- SH could join the LVC meeting only in the first two days (parallel sessions) mainly in AIC and joint instrument plenary
DCC link to the agenda (Many of them are not KAGRA-readable)
Some topics picked up by SH
kHz optimization for BNS post-merger (Haixing Miao)
- Long SRC to dig into high frequency (kHz) region. Sensitivity will be limited by SRC loss.
- Typically 6km arm with 150m SRC to make some detection of post-merger (~1 event/year)
- 18 km arm may be needed to do some astronomy (~10 events/year)
- python implementation
- It enables custom detectors (e.g. homodyne detector)
- It can take account of 3G detectors (e.g. polarizing beam for Sagnac)
Low loss Faraday Isolator for squeezing injection
- Try to reduce the optical loss which is limiting the squeezing level (currently ~3dB at LIGO)
- Matteo's contribution mentioned
High power laser for O4 and 3G
- Original High Power Oscillator (HPO) was given up due to the maintenance issue and the beam jitter affecting the sensitivity
- Two neoVAN-4S-HP (solid state) amplifiers (+70W each) in series following LIGO front-end laser (30W) or NPRO seed (2W) to get 140~170 W power for O4
- Development of fiber amplifiers at LZH in progress. To be tested at AEI Hannover soon.
- Coherent beam combining (CBC) with two neoVAN-4S-HP amplifiers and/or fiber amplifiers can be tested at AEI Hannover.
- Benno's AEI Hannover group is always supportive to KAGRA
Gingin facility at UWA (DCC link is not KAGRA-readable)
- Study on Parametric Instability - possible collaboration for KAGRA+ ?
- 5W 2micron laser for silicon mass cavity
- Sensitivity improved from 25 Mpc to 40 Mpc by mitigating actuation electronics common mode noise coupled with electro-static charges
- Electro static charge issue is important even for coil magnet actuator for Virgo (and KAGRA) and not only for ESD in LIGO
- Still unknown noise around 100 Hz which avoids achieving stable sensitivity of 60 Mpc for Virgo (possibly still actuation noise ?)
- LLO commissioning (DCC link is not KAGRA-readable)
- Noise projection to O3; ER14 120-140 Mpc
- Stable operation with 40W laser power but more noise with 50W
- 3dB IFO measured squeezing achieved
- Reduced ESD noise and stray field monitoring
- Non-uniform absorption at TM optics - serious problem avoided for now by moving the beam position
Musical VCOs => for more robustness
- Should be no big surprise for O3
- Squeezing at MIT (DCC link is not KAGRA-readable)
Why not more than 3 dB ? => Angle noise, Losses, Pump power and Radiation pressure (in principle)
- Loss inside IFO: 30% expected but in reality 4~50 %
- Towards O4: more than 3dB, A+ goal: 6dB (measured squeezing level)
- Silicon Suspension design and noise estimation updated by K.Arai
- Is it really good to use the ribbon suspension ? (SH's personal thoughts and also discussion with Helios)
- Tuning of quantum noise to be considered ; one possibility like high frequency tuning (related to Haixing's talk)
- Coordination of prototypes (S.Hild)
- Global coordination of prototype facilities is needed and also to be discussed among (LSC, Virgo, KAGRA, GWIC, ...) (David Shoemaker)
- After the GW detection we are more restricted to keep observation for science (Ray Weiss)
- If we have 4~5 detector in the world (including KAGRA and LIGO-india) we can rotate the down time for the upgrades ?
- Still not clear conclusion in this meeting how to coordinate and define the roles of each prototype facilities
- Looks like to be getting one of the major issues
- 4 out of 8 TM optics at LHO and LLO show some indication of point absorption
KAGRA+ (5~6 comments/questions were given)
(David) what is the time scale ? => Something like O5 and beyond
High power (HF) option is to give up the cryogenics ? => No we keep basically around 20 K by thicker and/or shorter fiber suspension
Suspension with different material with higher Young's modulus ? => We should consider about that
Long filter cavity possible ? => in principle yes but the space inside the tunnel is limited; 30m is Ok >30m needs some efforts
EPR entanglement should need shorter filter cavity => we should consider some QND for the far future options