== Mirror Q == * '''Offsite mirror Q measurement meeting on 15th November 2023''' * [[attachment:Sapphire Q measurement 20231115.txt|Memo]] * [[attachment:2023.11.15-Q measurement meeting.pdf|slides by Bajpai]] * Discussions * Mirror Q measurement : Design of apparatus (Yamada and Suzuki) * Yamada-kun showed a quotation. He also showed cost for optical components, frame, and for contingency. Miyoki-san approves and Yamada-kun starts to procure. The delivery will be on beginning of January 2024. * When, how, who transports "spare" mirror from NAOJ and KEK ? -> Kazuhiro asks Aso-kun. * For cryogenic experiment, tungsten wire brittleness must be checked. -> Apparatus is in KEK. Suzuki-san knows well. * Stainless dummy mirror (size and weight are same as those of KAGRA sapphire mirror).-> Kazuhiro sends later from Toyama to KEK. * What kinds of glue we use is still open question. * Fiber Q measurement (Bajpai) * Fiber Q measurement apparatus : Part are delivered by Christmas. Fiber samples at Kashiwa and Tsukuba will be measured at first. * Bonding Q measurement Which kinds of bonding is checked is still open question. Rishabh-kun needs details of electrode for electrostatic actuator. -> Kazuhiro sends later. * A/I * Kazuhiro consults with Aso-kun transportation plan of "spare" sapphire mirror. * Suzuki-san tells details of apparatus to check brittleness. * Kazuhiro sends stainless dummy mirror from Toyama to KEK. * Kazuhiro sends details of electrode for electrostatic actuator to Rishabh-kun. * Open questions * Which kinds of glue for wire breakers ? * Whick kinds of bonding is checked ? * '''On-site substrate Q-value measurement kick-off meeting on 24th October 2023''' * Komori's presentation ([[https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=15363| slides]]) * Discussions * The 29.7-kHz mode cannot be excited because the edge of the surface is almost a knode. * We can start the measurement from the butterfly mode or the 01-ish mode. * We will try the case 2 at first (up-conversion method). * Function generators and mixers should be prepared. * A/I * KTanaka will check the function generators available. * Komori will check or order mixers. * Komori and KYamamoto will discuss which modes are measurement targets. * '''Offsite mirror Q measurement meeting on 10th October 2023''' * [[attachment:Sapphire Q measurement 20231010.txt|Memo]] * [[attachment:231010_MIRQ_tyamada.pdf|slides by Yamada]] * [[attachment:|slides by Bajpai]] * Discussions * Onsite Q measurement: Q (24kHz) of all mirrors around 250K are on the order of 10000. https://klog.icrr.u-tokyo.ac.jp/osl/?r=27117. Q (24kHz) of both ITM's (ETM's) around 80 K are on the order of 1000000 (100000). https://klog.icrr.u-tokyo.ac.jp/osl/?r=26904. * Mirror Q measurement : Design of apparatus (Yamada and Suzuki) * Yamada-kun introduced quotation and Miyoki-san shows his idea for budget. * A/I : Yamada-kun will consider which parts are made by companies or KEK machine shop (trade off of budget and lead time). * Aso-kun's requests the measurement of Q of polished bulks for new ITM on January 2024. * HCB box can be used as jig for wire breaker gluing (Ushiba-kun agrees). * Onsite violin Q measurement (Komori) * Q-values of first violin mode are derived from measured peak width of power spectrum. https://klog.icrr.u-tokyo.ac.jp/osl/?r=26113 * Q around 250K (80K) are comparable with thremoelastic damping (Shishido-kun's measurement as below) * Fiber Q measurement (Bajpai) * Shishido-kun measured Q of fiber with sumiceram (as KAGRA sapphire fibers) without anyload. Q at 5K was about 10^5. He confirmed this Q is limited by fiber itself. *Rishabh-kun proceeds with preparation. His strategy is as follows. At first he measure Q of short monolithic fiber. If measured Q is high, he measures Q of KAGRA size fiber. Otherwise, he improve support system. He will prepare by middle of January. * '''Offsite mirror Q measurement meeting on 21st September 2023''' * [[attachment:Sapphire Q measurement 20230921.txt|Memo]] * [[attachment:230921_MIRQ_tyamada.pdf|slides by Yamada]] * [[attachment:Fiber Q.pdf|slides by Bajpai]] * Discussions * Onsite Q measurement: Q-value measurement of ITMY under 88K by M. Yamamoto (Toyama), Nakano (Caltech), K.Tanaka (ICRR). It was on the order of 10^6. https://klog.icrr.u-tokyo.ac.jp/osl/?r=26679 * Mirror Q measurement : Design of apparatus (Yamada and Suzuki) * Gluing system : We reuse HCB box and some parts fabrication is necessary. * A/I : Kazuhiro asks Ushiba-kun HCB box stocks and which can be used. * Ear's slit : We use ear's slit. Wires are almost along vertical direction. Four breakers are necessary for each wire. * A/I : Yamada asks Hirata-san details of wire breakers in Type B and Bp as reference later. *Budget : Quotation is sent by 6th October (Fri) * Fiber Q measurement (Bajpai) *Frame : Stainless ? *High voltage supply in KEK must be checked (specification and whether they work). *Budget : No so many ? * '''Offsite mirror Q measurement meeting on 24th August 2023''' * [[attachment:Sapphire Q measurement 20230824 revised.txt|Memo]] * [[attachment:230824_MIRQ_tyamada.pdf|slides by Yamada]] * Discussions * Stocks of bulks with ears : Two pieces were found at NAOJ * Offsite Q measurement: M. Yamamoto and Y. Sato (U Toyama), K. Komori (U Tokyo), K. Tanaka (ICRR) are measuring Q of ETMX (about 30K). We are afraid that AR side is covered by frost. * Design of apparatus (Yamada and Suzuki) * Clamp : Wire inclination is 10 degree to avoid any bending of wire. * Wire breakers : Long breakers (2 pieces) or short breakers (4 pieces) ? -> Shorter ones to avoid effect on Q. * A/I : Yamada asks Hirata-san details of wire breakers in Type B and Bp as reference later. * Wire breakers : The best distance between 2 loop wires for Q measurement is one third of mirror thickness. * A/I : Yamada and Suzuki check the size of breakers for wires in slits. * Glue : Glue must be removed. What kinds of glue ? -> We continue discussion. * Earthquake stopper and Actuator : Actuaor electrode which has hole or gap for laser beam is on HR side. Soft large parts are on HR side and screws are on AR side as HCB box. Earthquake stopper must be considered carefully. *A/I Yamada and Suzuki revise or consider design of actuator and earthquake stopper. *Installation : Misumi frame, lab jack, and roters. *Budget : Miyoki requests quoation for discussion. * Yamada and Suzuki asks quotation. * '''Offsite mirror Q measurement meeting on 3rd August 2023''' * [[attachment:Sapphire Q measurement 20230803.txt|Memo]] * [[attachment:230803_MIRQ_tyamada.pdf|slides by Yamada]] * Discussions * Evaluation of Q by residual gas damping: It does not matter * Sample : ETMX spare mirror with ears at Mitaka. Nothing at Kashiwa. We look for spare IMTY -> After this meeting, it was found at Mitaka. * Design of apparatus (Yamada and Suzuki) * CLIK with optical table area near cryocooler. * Tungusten wires (0.4mm or 0.5mm in diameter) is necessary. The end of wire is clamped. * Stand off -> Yoich asks R.Takahashi-san whether we have spare stand off (wire breaker) and design drawing of stand off.-> Hirata-san told details after this meeting. * Electrostatic actuator : 1mm gap is enough. -> Anyhow, Earthquake stopper and installation tools are necessary. *Others : Before new ITM HCB, we would like to identify cause, at least. Fiber must be also investigated. *A/I *Yamada and Suzuki : Design of experimental apparatus is revised. * '''Offsite mirror Q measurement meeting on 19th July 2023''' * [[attachment:Sapphire Q measurement 20230719.txt|Memo]] * Discussions * Our first priority is room temperature measurement. Then cryogenic temperature (around 20K and 100 K). * Sample : We will check our stock (Ushiba at Kashiwa, Aso at Mitaka). * For Suspension, frame, 2 loop wires, and jig to suspend are necessary. * Sensor : Michelson interferometer * Komori and Rishabh can assist Yamada. * Schedule : 6 months for room temperature measurement as first plan (if necessary we will change) *Design by end of August *Procurement : 3 months *Measurement *A/I *Yamada and Suzuki : Design of experimental apparatus *Ushiba and Aso : Sapphire mirror stock checks at Kashiwa and Mitaka *KYamamoto : Evaluation of Q by residual gas damping * '''Chattig after CRY meeting on 12th July 2023''' * [[attachment:sapphire mirror Q 20230712.txt|Memo (Japanese)]] * Discussions * Vacuum chamber : If T. Yamada conducts, it must be at KEK. * Sample : We will check our stock. * Actuator : Elecro static * Sensor : Michelson interferometer * Support : Wire suspension or nodal support system ? Nodal support system for heavy sample is quite difficult. However, wire suspension must be designed carefully not to decrease measured Q. * '''Chief Meeting on 10th July 2023''' * Concerns * Suspended sapphire mirrors' Qs ([[https://klog.icrr.u-tokyo.ac.jp/osl/?r=23870| ITMX]], [[ https://klog.icrr.u-tokyo.ac.jp/osl/?r=24266|ITMY]], [[https://klog.icrr.u-tokyo.ac.jp/osl/?r=23677|ETMX]], [[https://klog.icrr.u-tokyo.ac.jp/osl/?r=25916|ETMY]] ) were measured to be~ 10^4^ order that was expected to be over 10^5^. * Why Qs of mirrors were so low?? * K. Yamamoto-kun(U Toyama) [[attachment:sapphire mirror Q 20230707.txt|presentation]] * Discussions * Nodal support is difficult and desired to be avoided for the excellent substrate in NAOJ. 2 loops pending by Tungsten wires? We need wire breakers/stand-offs. * AZTEC sapphire bulk in NAOJ should be polished on the side. * Measure at room temperature. * Electro-static actuator is desirable.