= Satellite Meeting on Future Upgrade of KAGRA = [[LCGT/Meeting/f2f/2019August|Main F2F Page]] == Date/Time/Venue == August 21th (Wed.) 13:00 - 16:10 (We would like to finish the main discussions by 15:30, when [[LCGT/Meeting/f2f/2019August#Tour|the KAGRA site tour]] starts) Venue: Multi purpose room (多目的ホール), [[http://www.sci.u-toyama.ac.jp/EN/aboutus/guide.html|Faculty of Science]], [[https://www.u-toyama.ac.jp/en/access/gofuku/index.html|University of Toyama, Gofuku Campus]] ('''''Note that different from the venue of F2F meeting''''', [[LCGT/Meeting/f2f/2019August#Venue|Kuroda hall]]) Zoom(2) connection: https://zoom.us/j/6676627462 Anyone are welcome to join the discussions on site or via online and for even those who didn't make a registration. == Related information == * [[LCGT/Meeting/f2f/2019Apr/FuSat|The last satellite meeting in April/2019]] * [[http://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA/KSC/FPC|FPC wiki]] * [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9590|FPC White Paper]] == Program == ||Time ||Subject and Title ||<24% style="text-align:center">Speaker ||File || ||13:00-13:10 ||||'''Introduction''' || || || ||Introduction from FPC ||S. Haino and FPC ||[[#Agenda|(↓)]]|| ||13:10-14:00 ||||'''Mirror and Cryogenics''' || || || ||Sapphire Mirror||M.Leonardi,T.Tomaru||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=10568|o]] || || ||Heat extraction||T.Yamada,T.Tomaru||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=10569|o]] || ||14:00-16:00 ||||'''Upgrade plans''' || || || ||Upgrade plans and publication||S. Haino and FPC ||[[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=10567|o]]|| ---- <> == We would like to get agreements (understandings) by KAGRA collaborators on: == * Due to the ITM issues, O5 plans should be more realistic (DRSE 150 Mpc ~ BRSE+FDsqz 170 Mpc) * Define and share the ultimate goal (100~200 kg TM 300~500 Mpc ?) towards 2030’s * White paper (WP) will be two parts: (1) Survey and list of facts and (2) Recommendation of plans and science scenario * WP(1) to be officially approved [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9590|JGW-M1909590]] * WP(2) will be drafted by October for the internal review by KAGRA in/by Dec. F2F, and eventually to be published after KAGRA joins O3 * WP can be referred for funding requests/proposals /* By considering the current ITM issue, KAGRA/KAGRA+ configuration in O5 to be BRSE+FDsqz (170 Mpc) with DRSE (150 Mpc) as a backup => this is a Broad-band option */ /* Define the ultimate goal of KAGRA towards 2030's (until 3G observation starts) with heavy mass (100~200 kg) and high power (350~500 W) laser to achieve 300~500 Mpc sensitivity. => this is a broad-band option */ /* The strategy and path between O5 and ultimate can be discussed according to the technological feasibility and science cases */ <> == Minutes (by K.Yamamoto and SH) == * Sapphire mirror issue (M. Leonardi) * iLM(Geppo) is on last stage but his original proposal does not mention birefringence. * Now iLM is interested in studying birefringence issue => could be the best solution * For near future (O4), 200ppm/cm absorption can be accepted. * Internal stress causes birefringence ? Annealing parameter of vendor are not known. * ITM for O4 : By re-polishing and same time coating, finesse unbalance could be solved, but birefringence can not be solved (same order of magnitude). * Is it worth ? Budget and schedule should be considered. Evaluation by commissioing is necessary (which (finesse unbalance or birefringence) is large must be known). * Or fused silica for O4 ? -> coating thermal noise could be an issue. Suspension improvement is necessary. Thermal compensation system is necessary. * Silicon test mass ? -> still far future ? * IBF (Ion Beam Figuring) can solve only 1 DoF (S-pol) out of 2 (S,P-pol) * Heat extraction capacity (T. Yamada) * Thermal resistance must be reduced and possible (factor 2) at least for the contact ones. * For the sapphire fiber, temperature dependence of thermal conductivity is not taken into account. * About 10 K/W out of 35 K/W are from sapphire fiber * Heat link is x2 longer than original design * 35 K/W may be achieved * Upgrade plans and publication (S. Haino) * ET fixed with 1.5 um wavelength which CE2 is aiming at 2 um which have advantage in the scattering * Publication plan -> First purpose of FPC is PREPARATION of white paper. * For the publication, we have to discuss EO (about feasibility, budget, schedule) * WP should be prepared for the coming budget proposal, and contribution from FPC is expected ? * We should remove the recommendation part from the first release to make it as list of facts * Realistic option for O5(perfect 22 kg mirror and FDSQZ) proposed is minimum success. * Silicon mirror changes a lot of thing. * Ultimate goal of KAGRA (final BOSS) * Boundary condition must be defined at first. <> == Agenda == * Things happened since [[LCGT/Meeting/f2f/2019Apr/FuSat|the last satellite meeting]] * O5 plans (A+,AdV+) and schedule are [[https://dcc.ligo.org/LIGO-P1900218/public|released to public]] * Schedule of 3G (ET, CE) released in [[https://agenda.infn.it/event/15928/|GWADW 2019]] * A new proposal [[https://indico.ego-gw.it/event/20/contributions/401/attachments/292/432/DEM_DAWN5_Oz_roadmap_v2.pdf|ozGrav-HF]] * [[http://ilm.univ-lyon1.fr/index.php?option=com_content&view=article&id=973|iLM]] submitted a proposal to produce large sapphire bulk up to 200~250 kg and aiming low heat absorption (< 10ppm/cm) * ITM birefringence issue found (e.g. [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=10369|JGW-G1910369]],[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=10495|JGW-G1910495]) * Science study updated by A.Nishizawa [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9934|JGW-G1909934]] by considering LVK network * We have a session dedicated to sapphire mirror and heat extraction * Understand the current status of sapphire mirror issues and future prospects * Maximum laser power is limited (at least) by the heat absorption and heat extraction capacity. We should understand the current estimation. * We would like to get agreement/understanding on the followings: * Publication on the KAGRA future upgrades * Define the ultimate goal in long term towards 2030's * More realistic plans for O5 * Publication plan (Full KAGRA author) * Serve as the 2nd release of the white paper * Discussion about the ultimate goal and intermediate plants including O5 * Share the same idea inside the collaboration as well as to inform it to LV and near-by communities * Submission/publication target just after KAGRA manage to join O3 (late 2019~early 2020 ?) * Target journal: PRL or PRD ? (depending on the number of pages/figures) c.f. iKAGRA => [[https://academic.oup.com/ptep/article/2018/1/013F01/4817346|PTEP]], bKAGRA-ph1 => [[https://iopscience.iop.org/article/10.1088/1361-6382/ab28a9|CQG]] * Ultimate goal of KAGRA * Time scale around 2030 * It should fill the gap between O5 and 3G * 200 kg Sapphire as the primary candidate (iLM may help us a lot if their proposal is accepted) * Backup plan with Silicon ? Decision tree should be prepared * With 200 kg sapphire and 500 W laser, 500 Mpc may be possible [[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=10533|JGW-G1910533]] * What is the name ? Naming is important: hKAGRA ? (hyper-KAGRA, or h as Heavy-mass and High-power), uKAGRA ? (ultimate-KAGRA) or dKAGRA ? (dream-KAGRA) * More realistic plans for O5 * Due to the ITM issues it may be difficult to achieve the design sensitivity during O4 * One option is to achieve the design sensitivity (with detuning) of 150 Mpc in O5 * Detuning doesn't go well with squeezing. Should we give up detuning but BRSE with FD squeezing (60m filter cavity ?) * High Freq. (HF) upgrade requires R&D and change of suspensions which may have a risk to worsen the sensitivity, while FD squeezing can be installed independently so that we can go back to detuning option if the installation of squeezing doesn't finish in time