== FPC Meeting on 2019/05/20 17:00 - (JST) ==
Participants: Kentaro Komori, Atsushi Nishizawa, Kentaro Somiya, SH
/* Chunglee Kim, Kentaro Komori, Matteo Leonardi, Yuta Michimura, Atsushi Nishizawa, Kentaro Somiya, SH */

Zoom meeting(2): https://zoom.us/j/6676627462

 * Next meeting will be in early June before KIW ? (doodle poll will be circulated).
 * [[KAGRA/KSC/FPC|Back to FPC page]]

== Action items ==
 * Update science scenario with new scoring while keeping the optimistic case for the funding request (Nishizawa)
 * Update technology section and add another column like "additive" in the technology scoring sheet (Somiya)
   * DECIGO, Optical levitation, icing of TM, cooling capacity(?), ...
 * Science Figure of Merits (FoM) for each scenario (Haino, Nishizawa, ...)
 * New sensitivity curves (Haino, ...)

== Minutes ==
 * Any feedbacks from KAGRA collaboration since the last f2f ?
   * K.Yamamoto-san is checking the white paper
   * Related with Observing Scenario Paper (OSP) preparation, timelines towards O5 is in a discussion in LIGO. Currently, O5 will start in late 2024, while the duration of O4 is still in discussion (ranging between 1~2.5 years). So it is not clear how long we will have between O4 and O5.
 * Science scenario (Nishizawa et al)
   * Scoring updated by considering detector network (A+, AdV+ and K or K+)
   * Scores for many science topics get worse as 0 (less than 20%), which is reasonable.
   * Improvement in the polarization measurements ? => If K or K+ (4th detector) sensitivity is not good the improvement is also limited
   * LF, BB and HF scenario
   * Primary and secondary science targets
   * Instead of choosing one or two (or dropping one) we should plan to achieve all the scenario but put priorities and time scale for each scenario
   * Based on technological scoring, FD-squeezing and HP laser are more feasible than heavy mass and/or suspension thermal noise improvement. 
   * Following the technological feasibility study, we consider BB and HF as near-term scenario and include LF as middle-term scenario
 * Science Figure of Merits
   * We want to evaluate each science scenario in the quantitative way. (e.g. [[https://arxiv.org/abs/1902.09485|arxiv:1902.09485]] thanks to Somiya-san)
   * Proposal: BBH(100?) range for LF, BNS(1.4?) range for BB and sky localization range* for HF
   * Sky localization range*: average distance to achieve sky localization confidence area < X deg^2 (e.g. X= 20 ~ 16 @ GW170817)
 * Additional scoring of technologies
   * Cost and risk in the scoring ? Are they already included in "Feasibility" ?
   * Let's add "additive" in the scoring
 * New sensitivity designs
   * Production of new sapphire mirrors is the key to understand the baseline
   * Currently, we have no plan to produce new sapphire mirrors until O4, i.e. we will go without any spare ITM/ETM
   * A few weeks ago, Tomaru-san and SH visited [[http://ilm.univ-lyon1.fr/index.php?option=com_content&view=article&id=973|iLM]] and discussed with Geppo and his group. As shown in [[https://indico.ego-gw.it/event/12/contributions/273/attachments/188/281/Cagnoli_KV_2019.pdf|KIW5]], they submitted a proposal to procure a big oven in order to produce large sapphire bulk up to 200~250 kg and aiming low heat absorption (< 10ppm/cm).
   * If this is realized, sapphire can be a good candidate also for 3G competition with Silicon.
   * Since we benefit for both sides, PI and deputy-PI agreed to support their proposal and consider the collaboration.
   * As a FPC-related activities,  SH is now researching a few companies for the polishing because it is one of the most costly and time consuming part. Based on the suggestion by deputy-PI, SH has briefly reported about this in today's chiefs meeting. Even though Matteo is currently the chief of MIR, it is a heavy duty for him to work both on sapphire mirror and squeezing/filter cavity. We should better share the work.
   * First let's define a big goal (dream) to use 200kg, 10ppm/cm absorption sapphire and see which sensitivity curves we can achieve. Heavy mass will help not only the radiation pressure noise but also suspension thermal noise.
   * Can this "dream" plan go with 3G (ET and CE) to improve e.g. sky localization, or anything else ?
   * Then for O5, we should consider at least two cases: optimistic and pessimistic, assuming, FD squeezing and HP laser are feasible in 5 years.
   * Optimistic case: we will produce new sapphire mirrors (even with 22kg) with ITM issues fixed and some possible tunings for the Finesse (like extreme RSE ?) and hopefully some improvement of heat absorption ? (20~50 ppm/cm ?)
   * Pessimistic case: we will not produce sapphire mirrors even for O5 and we have to use the current one
   * We should limit the range of suspension fiber length (>30 cm ?)
   * For each cases (dream-3G, optimistic-O5, pessimistic-O5), we can evaluate the improvement with respect to 2G-O4 for three science scenario (LF, BB, HF)
 
 * PAB report (Somiya)
   * There was a question about the general scheme that each group should obtain the funding to do upgrades. Should it be better that young people decide what to do ?
   * Data analysis pipeline should be discussed in DAC white paper (or LVK white paper ?) instead of FPC white paper.
   * We should invite experts in the system engineering (SE) or some of us should take a SE lecture like JAXA does.
   * What is the advantage of underground for HF option ? The sensitivity curve for LF looks not so good.
   * Issues on the ITM non uniformity.

 * Mirror risk management
   * Currently, we don't have any spare for ITM nor ETM. If some accident happens to TM, KAGRA project can end at that point.
   * As a framework and motivation of FPC, SH is looking for some alternative companies for the polishing
   * Some company says that they can polish in nm-precision roughness but large curvature is not feasible. 
   * Can we modify the IFO design to make an arm cavity even with flat TMs ? If so this could help us to reduce the TM procurement cost. 

 * Conferences
   * [[https://agenda.infn.it/event/15928/|GWADW (Elba), May/19-25]] - [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=10157|M.Leonardi]], [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=10222|K.Yamamoto]]
   * [[http://kiw6.csp.escience.cn/dct/page/1|KIW6, June/21-23]] - A.Nishizawa(science review including O3,O4,O5) and S.Haino(FPC overview and white paper)
   * [[https://www.gr22amaldi13.com|Amaldi conference (Valencia), July/7-12]] - Y.Michimura, (and H.Shinkai for KAGRA status talk)