Cryogenic System Integration Meeting 2014 FY
2015.3.17
2015.3.10
2015.3.3
2015.2.17
2015.1.28
Management & Schedule (Suzuki):
- Installation (Kimura, Kume, Tomaru, Suzuki)
- Seismic Vibration Measurement
- Tunnel CAD:
Surveying : 20150123 alignment result Kume.pptx
- DAQ:
- Mirror Cryostat (Sakakibara, Kimura, Tomaru)
- Assembly:
- Top shield pipe for SAS: We have to product two other top shield pips for front-Cryostat.
- Signal output from Cryogenic Subsystem:
- Duct Shield (Sakakibara, Kimura):
- Cryocoolers (Tomaru, Suzuki):
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Design (PF, IM, IMR):
- Fabrication (PF, IM, IMR):
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Full size prototype :
- One fiber prototype :
- Baffle :
- Test
Status of R&D
- Misc
2015.1.20
Management & Schedule (Suzuki):
- Installation (Kimura, Kume, Tomaru, Suzuki)
Seismic Vibration Measurement at Y-end:Y-end Summary.pdf
Tunnel CAD: I decided to make tunnel CAD, especially around Cryo&VI rooms, with reflecting surveying results. I asked Hagiwara-san and Kume-san to summary data and CAD. We must consider installation with this CAD.
- DAQ:
- I decided to use Cryocon for KAGRA cryogenic system. After our next fiscal year budget is ready,I will order all of Cryocon temperature monitors.
Data group recommend to use other local PC to monitor such temperature except for KAGRA DAQ system. -> We need 4 local PC at least.
- Kamikubota-san picked up our Cryocon to check its operation on EPICS.
- Mirror Cryostat (Sakakibara, Kimura, Tomaru)
- Assembly: Temporary flanges at sides and top has been taken off at Y-end. Temporary clean booth has been set. We start installation of top shield pipe and real large flanges.
- Top shield pipe for SAS: We have to product two other top shield pips for front-Cryostat.
- Signal output from Cryogenic Subsystem:
- Duct Shield (Sakakibara, Kimura): We will visit Torisha Co. tomorrow.
- Cryocoolers (Tomaru, Suzuki): We will visit Torisha Co. tomorrow.
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Design (PF, IM, IMR):
- Rough design of dummy mirror, recoil mass, intermediate mass has been done.
Not yet: Platform, intermediate recoil mass, sensor & actuators
- Fabrication (PF, IM, IMR):
- We ordered test fabrication of intermediate mass part to VIC Co., who is company that has technologies of high vacuum and vibration attenuation. Delivery will be end of Mar.
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Full size prototype : Design and manufacture for assembly jigs are in progress.
- One fiber prototype : Halogen lamp was delivered.
Kieran Craig (Glasgow) becomes a post doc of ICRR on the next July. He stayed in Kashiwa a few times and measure coating mechanical Q at cryogenic temperature. This result was summarized as the paper of PRD (http://journals.aps.org/prd/abstract/10.1103/PhysRevD.90.102004) and Kieran is the second author.
- Baffle :
- Test
Status of R&D
- Misc
- Design (PF, IM, IMR):
2015.1.13
2014.12.16
2014.12.09
Management & Schedule (Suzuki):
- Installation (Kimura, Kume, Tomaru, Suzuki)
Seismic Vibration Measurement at X-end:seismicXend.pdf
- We measured seismic vibration only at X-end cryostat room by using RION LA50 accelerometer and Guralp CMG-3T seismometer.
- The purposes of this measurement are;
- To check seismic vibration level at KAGRA site even if it has many water flow in the tunnel
- To check sensitivity level of both seismometer and accelerometer
- To check the effect of concrete cut at cryostat pit for interruption of vibration conduction
- To check effect of water flow around water pit
- Result;
- Seismic vibration level at KAGRA X-end was same as CLIO site. We confirmed 10^-9m/rHz seismic vibration at 1Hz. And we found that large micro-seismic vibration peak around 0.1-1Hz range.
- Sensitivities of our seismometer and accelerometer are comparable level between 0.2Hz and 200Hz range. But, the accelerometer can reach to sensitivity limit at 1-10Hz range.
- There are no apparent concrete cut effect. We think we don't need concrete cut, but SEO suggests to keep concrete cut to mitigate concrete stress due to clean booth and stuff.
- We found large excess of water flow at 10-200Hz range. But this effect was only observed at very close point from water pit, and was not observed at cryostat pit, which is about 10m far from the water pit.
- Clean Booth CAD from SPE:
- DAQ: I visited to Osaka City Univ. and discussed about DAQ of thermometers.
- Use of Cryocon temperature monitor maybe useful for DAQ
- If there is a EPICS driver for this machine, it is very easy to connect to KAGRA DAQ system. Maybe KEK accelerator lab. know about it.
->
- I asked my acquaintance in our CSC. In neutrino beam line, temperature monitor outputs are converted to analog signal once and acquired by analog DAQ device with EPICS output.
- Kamikubota-san in Accel. Lab. told me, there seems not to be Cryocon driver. But it is not hard work to write such driver program since Cryocon temperature monitor has IP and Ethernet port.
- I decided to use Cryocon for KAGRA cryogenic system
- Data group recommend to use other local PC to monitor such temperature except for KAGRA DAQ system.
- I showed POLARBEAR quick look (web base) to Hayama-san, and he will develop similar quick look for KAGRA.
- Mirror Cryostat (Sakakibara, Kimura, Tomaru)
- Top shield pipe for SAS:
- Signal output from Cryogenic Subsystem:
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki):
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Miyamoto,Tomaru):
- Recoil mass
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Full size prototype : Toyoda-san is writing design of jig for Hydroxide Catalysis Bonding.
- One fiber prototype : Indium bonding is in progress. After this bonding, the one month test starts.
- Zygo investigation : ?
- Q of sapphire fiber : Even though clamp was suspended, Q is still about 10^6. Ettore brings ?
- Kazuhiro summarized the report about his official trip in Europe (12th-22nd Nov).
- Vertical Spring (Tomaru):
- Baffle :
- Test
Status of R&D
- Misc
2014.11.26
Management & Schedule (Suzuki):
- Installation (Kimura, Kume, Tomaru, Suzuki)
- Clean Booth CAD from SPE:
X-end Pit Measurement: memo2014.11.14_Xend.pdf
DAQ: http://wiki.kek.jp/pages/viewpage.action?pageId=37159465
- Mirror Cryostat (Sakakibara, Kimura, Tomaru)
- Top shield pipe for SAS:
- Signal output from Cryogenic Subsystem:
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki):
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Miyamoto,Tomaru):
- Recoil mass
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Full size prototype : In Progress (Factory send status e-mail)
- One fiber prototype : Finally, it was assembled ! Resonant frequency is the same as the calculation. Now, indium bonding is in progress.
- Zygo investigation : ?
- Q of sapphire fiber :
- Kazuhiro is summarizing the report about his official trip in Europe (12th-22nd Nov).
- Vertical Spring (Tomaru):
- Baffle :
- Test
Status of R&D
- Misc
2014.10.28
Management & Schedule (Suzuki)
- Installation (Kimura, Kume, Tomaru, Suzuki)
Clean Booth CAD from SPE: SPE_cleanbooth2.pdf Memo of Discussion (Japanese)
Y-end Pit Measurement: 0141027YendSurveying.pdf
MCE Surveying: 20141027MCESurveying1.pdf
- Mirror Cryostat (Sakakibara, Kimura, Tomaru)
- Top shield pipe for SAS:
- Signal output from Cryogenic Subsystem:
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki):
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Kazuhiro will explain the status of design in the payload meeting.
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Miyamoto,Tomaru):
- Recoil mass
We will purchase low magnetism stainless steel (Nippon Steel & Sumitomo metal)(Kazuhiro).
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Full size prototype : Kazuhiro sent the bulk.
- Zygo investigation : Design drawing was finished. Suzuki-san will send it soon.
- Q of sapphire fiber : Discussion in the cryo payload meeting
- Kazuhiro will attend ET meeting (19-20 Nov). Before this meeting, he visits Glasgow and discuss full size prototype with Giles. Moreover he also discuss with Geppo at Lyon about the same topic.
- Jerome stay in ICRR in this week. Kazuhiro asks something about mirror.
- Vertical Spring (Tomaru):
- Baffle :
- Test
Status of R&D
- Misc
2014.10.21
Management & Schedule (Suzuki)
- Installation (Kimura, Kume, Tomaru, Suzuki)
- Second cryostat was installed at X-end on the last week (15th-17th of Oct). Here are photos.
- Mirror Cryostat (Sakakibara, Kimura, Tomaru)
- Top shield pipe for SAS:
- Signal output from Cryogenic Subsystem:
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki):
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Miyamoto,Tomaru):
- Recoil mass
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Full size prototype : We ordered IMPEX (flat cut on barrel surface and ears). Kazuhiro will send the bulk in this week. We appreciate Sascha's effort as the contact person. Vielen Dank !
- Zygo investigation : Design drawing was finished. Suzuki-san will send it soon.
- Q of sapphire fiber : Discussion in the cryo payload meeting
- Vertical Spring (Tomaru):
Baffle : Wide-angle baffle so far(T. Akutsu)
- Test
Status of R&D
- Misc
2014.10.07
Management & Schedule (Suzuki)
- Installation (Kimura, Kume, Tomaru, Suzuki)
- Measurement:
- Beam level marking at Y-end
- Beam positions and cryostat position marking at X-end
We decided to share our photos in KEKGW wiki; http://wiki.kek.jp/display/gw/Photo
Items in/for Kamioka: http://wiki.kek.jp/display/gw/Tool+List
- Temporary Clean Booth for Cryostat Assembly: Kimura-san and Tomaru discussed this with Daiichi Tekko Co. who works with KEK frequently, and they can take it on. We decided that we will make small and simple clean booth only around opened flanges (top and both sides) by scaffolding pipes and Seiden-F sheets. Daiichi-Tekko is under planning and making quotation for this temporary clean booth.
- Clean booth at Cryo-room: SP Engineering Co. won this bidding. We had first meeting on Oct. 1. We have to tell them our requirements.
- Measurement:
- Mirror Cryostat (Sakakibara, Kimura, Tomaru)
- Top shield pipe for SAS:
- Signal output from Cryogenic Subsystem:
What signals will we give to DAQ system?: http://wiki.kek.jp/pages/viewpage.action?pageId=37159465
- Thermometers
- Vacuum gauges
- Cryocooler Compressors
- Seismometers?
- ?
- Slow DAQ plan to use Mitsubishi AJ65VBTCU-68ADVN/ADIN. This is not DAQ device but sequencer device with 4-pin connector input.
- The reason why this device was adopted is that this can convert analog signal to EPICS data easily, which is base data system in KAGRA. I feel that this device is not suitable for thermometer DAQ at least since thermometer output requires large dynamic range. I think we should convert thermometer output (voltage) to temperature data by temperature monitor and after that we should pass to EPICS data system. I will start data management from cryogenics group.
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki): We had OK for the CAD by Torisha Co.
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Miyamoto,Tomaru):
- Recoil mass
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Full size prototype : Design drawing was finished. Sascha will send it soon.
- Zygo investigation : Design drawing was finished. Suzuki-san will send it soon.
- One fiber prototype : Three blade springs were delivered. They look OK (by our eyes check). Design of the assemble jigs was finished. The problem is manufacturing.
- Mechanical dissipation of Hydroxide Catalysis Bonding : Dan will measure in Jena.
- Vertical Spring (Tomaru):
- Test
Status of R&D
- Misc
2014.09.08
Management & Schedule (Suzuki)
- iKAGRA vacuum chamber installation
- Installation (Kimura, Kume, Tomaru, Suzuki)
Measurement: We put base-plates for Corner Cube Reflector (CCR) of measurement tools (LaserTracker/TotalStation) in EYA area in last week since it will be covered by chambers in next week. Due to trouble of LT, we used TS in this measurement. The accuracy of the base position should be around 0.5mm. We could put base-plates on EAY room and duct-shield tunnel, but could not put them around EYC room. And we could not measure height level of the bases. We need more measurements in EYC, of cause EXC,FYC and FXC, too.
Base-plate location: CCR台座位置概略140903.pdf
Measurement result: Yエンド測量点増設20140902.xlsx
- How can we share these photos? My favorite is picasa web.
Items in/for Kamioka: http://wiki.kek.jp/display/gw/Tool+List
Temporary Clean Booth for Cryostat Assembly: 組立用簡易クリーンブースイメージ.pdf
- Mirror Cryostat (Sakakibara, Kimura)
- Top shield pipe for SAS:
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki): We had OK for the CAD by Torisha Co.
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
Moving Mass (Tomaru): We got control circuit kit to operate pytron stepping motor. -> Passed to Miyamoto-kun.
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Miyamoto,Tomaru):
- Recoil mass
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Full size prototype : Zygo decide to investigate damage on the reflective surface by flat cut. We must provide the design within two months.
- Bending length : Kazuhiro will show analytical result later.
- One fiber prototype : Mass and blade spring will be delivered by 12th and end of September, respectively.
- Strength test of Hydroxide Catalysis Bonding after thermal cycle : Dan will explain details later. At least, sapphire suspension can survive after 20 time thermal cycles !
- Mechanical dissipation of Hydroxide Catalysis Bonding : Dan will measure at Jena on October-November.
- Tanaka-kun and Miyamoto-kun visited KEK. Miyamoto-kun will go to KEK twice every week. Tanaka-kun supports Dan's sapphire fiber Q measurement in ICRR.
- Rahul and ANSYS : His result has already copied on backup server. ICRR Gravitational Wave Project Office keeps the ANSYS license in the next one year.
- Full size prototype : Zygo decide to investigate damage on the reflective surface by flat cut. We must provide the design within two months.
- Vertical Spring (Tomaru):
- Test
Status of R&D
- Misc
2014.08.26
Management & Schedule (Suzuki)
- 9/1-3: Measurement at Y-end by Kume, Tomaru, Suzuki.
- Installation (Kimura, Kume, Tomaru, Suzuki)
- First cryostat installation to Y-end was successfully done.: Suzuki, Kimua, Tomaru
- Measurement and alignment: We found that base-pin for measurement put by Kajima Co.was at center of cryostat position and we can not see it after cryostat installation. This means that we have to copy the base pin coordinate to other places; on floor and on wall.
- We plan to have measurement to copy base-pin coordinate on floor and wall from the Gate-valve room to Y-cryostat room.
Our measurement plan: 140826測量基準.pdf (Tomaru)
- It is an issue that we don't have concrete requirement for measurement and alignment accuracy.
- We found that Y-end room is pretty duty. How can we make clean up?
- Mirror Cryostat (Sakakibara, Kimura)
- Materials of two sets of SAS shield pipe has been ordered. (Suzuki, Kimura)
- We need simple clean booth to assemble cryostat until Nov. Kimura-san will have meeting with Torisha tomorrow. (Kimura)
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki)
- Torisha won the bidding to fabricate remain 5-50K cryocoolers. That is, Torisha will fabricate all of 50K cryocoolers. (Tomaru)
- Room temperature SAS (Sekiguchi, Takahashi)
- Colgate tube for Type-A was installed into vertical hole. (Tomaru, Kimura)
- It looks not to be vertical hole center, but vertical hole itself seems not to be completely vertical. (Tomaru, Kimura)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Tomaru): We got control circuit kit to operate pytron stepping motor.
- Recoil mass
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Full size prototype : Quotation arrived. Kazuhiro checked the procedure of purchase. Kazuhiro found some questions after he read quotation carefully. Sascha asked IMPEX. After all question will be closed, we will order immediately.
- One fiber prototype : Suzuki-san, Dan and Kazuhiro visited Shinkosha (6th of Aug). Although we were afraid that manufacturing of sapphire blade spring is quite difficult, it is possible. They showed the blade spring for cradle. But it was not polished. Polish itself started on the end of the last week. We must check progress.
- Rahul and Dan proceed with simulation. They explain the result in the cryo payload meeting.
- Vertical Spring (Tomaru)
- We moved the 1/4 cryostat to KEK. We have already open the cryostat.
Small CuBe blade test setup has been fabricated. Baking the CuBe parts was ordered to KEK machine shop.
- Test
Status of R&D
- Misc
- Rahul will leave on the end of the next week. We will discuss how to proceed.
2014.08.04
Management & Schedule (Suzuki)
- Cryostat Installation: Attendant=Suzuki, Kimua, Tomaru
- 8/12: Transportation from the storage container in Miyakawa-cho to Urushiyama-station. We will exchange trailer there by using a crane.
- 8/13: Departure from Urushiyama station at 5am and arrive at tunnel entrance at 8am. Transportation in Y-tunnel and estimated arrival time at Y-end is around 0pm.
- 8/18-20: Setting the cryostat at design position in Y-end.
- Cryostat Installation: Attendant=Suzuki, Kimua, Tomaru
- Installation (Kimura, Kume)
- We will have assembly of only the front-cryostats in this year by budget issue. This was not fixed in our meeting. We decide to pass several installation choices in this year to the SEO in this month.
- Mirror Cryostat (Sakakibara, Kimura)
- Materials of two sets of SAS shield pipe has been ordered.Will be fabricated in KEK.
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki)
- Public bidding for 5-50K cryocooler units was closed. Two company bade. Fabrication company will be selected on 8/6.
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Chen, Tomaru):
- Recoil mass
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Full size prototype : So far, no reply from IMPEX.
- One fiber prototype : Suzuki-san, Dan and Kazuhiro are going to Shinkosha tomorrow.
- Dan came back : He reports what he did and is going to do in cryo payload meeting.
- Rahul explains his calculation about thermal noise in cryo payload meeting.
- Vertical Spring
- We will move the 1/4 cryostat to KEK on this Fri.
Small CuBe blade test setup has been fabricated. Baking the CuBe parts will be performed in this Thur.
- Test
Status of R&D
- Misc
- Tanaka-kun and Miyamoto-kun (fresh persons of Kajita group) join. They will visit KEK after the middle of August when Takayuki has time. Tanaka-kun and Miyamoto-kun proceed with their experiment in ICRR and KEK, respectively.
2014.07.23
Management & Schedule (Suzuki)
- Cryostat Installation: preparation in strage container in 8/11, transportation to Y-end in 8/12-13.
- Installation (Kimura, Kume)
- We will have assembly of only the front-cryostats in this year by budget issue.
- Mirror Cryostat (Sakakibara, Kimura)
- Final CAD of the radiation shield pipe for SAS hole is completed now. We ordered materials for the fabrication in KEK. We asked quotations of washing of parts and black coating deposition.
- Auxiliary support structure at 4K shield to protect that payload fall on the 4K shield was also designed and its materials are ordered.
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki)
- Public bidding for 5-50K cryocooler units was closed. Two company bade. Fabrication company will be selected on 8/6.
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Chen, Tomaru):
- An early prototype of moving mass at cryogenic temperature was fabricated. We use a normal (non-cryogenic, non-high vacuum, but without oil) stepping motor produced by Oriental Motor Inc. This will be installed into 0.5W PTC at KEK. We also plan to use python stepping motor, but driver for the motor is under searching.
- Recoil mass
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Full size prototype : Sascha asked quotation of V cut and ears. They will reply within a few days, probably.
- One fiber prototype : Delivery will be delayed (about 2 weeks, on 9th of September). Kazuhiro is asking the status to Shinkosha. Toyoda-san proceeds with design drawing of jigs.
- Dan in Jena : Indium mechanical loss, thermal resistance of bonding, thermal noise calculation : We will discuss indium mechanical loss at 17:00 of today.
- Vertical Spring
CuBe vertical spring test by 1/4 cryostat was prepared in last week. We could not get signal by Ono-Sokki laser interferometer, but could have signal by Keyence laser-displacement sensor. However, the measurement was success only with over 5mm excitation. That is, we need exciter. The introduction of the exciter is not so easy.
- Measured resonant frequencies @300K: Pendulum mode = 0.9Hz, Vertical mode = 2.3Hz.
- I found that it is difficult to have effective operation of this cryostat in Kashiwa. I decided that we move the 1/4 cryostat to KEK and continue the experiment there.
Small CuBe blade test is planed in KEK and it is under fabrication.
- Test
Status of R&D
- Misc
2014.07.15
Management & Schedule (Suzuki)
- Cryostat Installation will delay. We don't have new schedule yet.
- We hires new senior technician, Terashima-san, for machine engineering. He is pretty specialist for fabrication. He works in KEK GW group on every Wed.-Fri.
- Installation (Tomaru, Suzuki)
- Kimura-san plan to postpone to assemble the both end-cryostats in this fiscal year because of our budget and schedule issue. He proposes to assemble only front-cryostats for iKAGRA in this FY. Do you feel any problem about it?
- Mirror Cryostat (Sakakibara, Kimura)
- Duct Shield (Sakakibara, Kimura)
- We had first kick-off meeting for duct shield and cryocooler fabrications with Torisha.
- The shield pipe at the connection between duct shield and cryostat was discussed.
- Final check of the radiation shield pipe for SAS hole was done in KEK. After several minor improvement, we will start fabrication in KEK in-house. We will fabricate two sets of the shield pipe until Nov. MLI used in the shield will be diverted from Toshiba duct shield, which are decided to be remodeled to 6m vacuum pipes.
- Cryocoolers (Tomaru, Suzuki)
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Chen, Tomaru):
- Recoil mass
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Preparation for full size prototype : Dan wrote drawing of bulk with flat cut and ears. Dan, Sascha and Kazuhiro proceed with final check. Sascha will start soon to discuss with IMPEX about flat cut and ear.
- Dan proceeds with measurement of mechanical loss of indium, thermal resistance of bonding, calculation of thermal noise in this week.
- Test
Status of R&D (K. Yamamoto)
- Kume-san and Takayuki start the preparation of vertical metal spring in 1/4 cryostat.
- Misc
2014.07.08
Management & Schedule (Suzuki)
- Schedule of installation (it does not include assembly) of cryostats at Y and X ends
- 14th of July (Mon) : Kimura-san goes to Hida-city.
- 15th of July (Tue) : Kimura-san and Staffs from Torisha visit the warehouse and KAGRA site. Suzuki-san goes to Hida-city.
- 16th of July (Wed) : Suzuki-san and Kimura-san have a meeting with MESCO.
- 31st of July (Thu) : In night, the first cryostat will be transported from the warehouse to KAGRA site entrance via Inotani.
- 1st of August (Fri) : The cryostat will be moved from the entrance to the center room.
- 4th (Mon) - 9th (Sat) of August: The cryostat will be transported to Y end.
- The second cryostat will be installed at X end between 13th (Sat) and 20th (Sat) of September.
- We must consider "shift" for the above schedule, especially, after November (Assembly of cryostat. We also install the pipes for Type A).
- Schedule of Mockup test (Mockup of cryostat is carried in the tunnel) is not still clear.
- We must take care of the hole for base (granite) of Geophysics Interferometer in the tunnel.
- Installation (Tomaru, Suzuki)
- Mirror Cryostat (Sakakibara, Kimura)
- Duct Shield (Sakakibara, Kimura)
- Measurement of heat transfer by cryogenic duct : The heat transfer of the 1st and 2nd ducts is 0.2% and 0.6%, respectively. The latter one is at almost upper end of error bars. We will investigate.
- Somebody will learn how to use application software and calculate transfer heat and so on (Yusuke will teach).
- Result of bidding (3 ducts) : Torisha
- Toshiba duct will be improved.
- Cryocoolers (Tomaru, Suzuki)
- 5 cryocoolers : Bidding is prepared.
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- In this fiscal year, the budget is so small. We will order Mechanical Engineering Center of KEK.
- Moving Mass (Chen, Tomaru):
Driver is expensive. VSS bipolar parallel wind -> Other company motor and driver can be compatible.
- Design drawing of cryogenic test was written.
- Recoil mass
- Design based on Type B is being considered.
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Preparation for full size prototype is in progress. Dan is drawing ears and almost finished. Sascha will start soon to discuss with IMPEX about flat cut and ear.
- Kazuhiro summarized budget for sapphire suspension (not only sapphire parts but also assembly jigs and so on).
- Dan proceeded with measurement of Q of bonding at Jena.
- One fiber prototype was ordered (Shinkosha).
- Test
Status of R&D (K. Yamamoto)
- Vertical metal spring (Tomaru)
- Kume-san and Takayuki will proceed with experiment in the 1/4 cryostat.
Terashima-san and Takyuki will start the experiment with small CuBe pieces.
- Vertical metal spring (Tomaru)
- Misc
- Information in yesterday chief meeting (Yamamoto)
- 2.6 m Maraging bar for Type A will be delivered on July 2015 (because of lack of budget !) (From Takahashi).
- Uraguchi-san, who is a technical staff in ATC (NAOJ) has expertise of parts with sliding capability at cryogenic temperature (From Akutsu).
- Information in yesterday chief meeting (Yamamoto)
2014.06.24
Management & Schedule (Suzuki)
- Yesterday, the result of the bidding for cryo duct and three cryocoolers are announced. 12.7 million yen in the red.
- Installation (Tomaru, Suzuki)
- The schedule for Yend cryostat installation is not still clear. Probably, on August, but it could be on July. We ask MESCO to test with mock up (whether mock up of cryostat can be transported in tunnel without troubles).
- KEK group asks quotation for car leasing. Parking are is also being looked for.
- Mirror Cryostat (Sakakibara, Kimura)
- Pipe for SAS : Koike-san and Kume-san proceed. Koike-san will prepare drawing of parts (for cost evaluation).
- Duct Shield (Sakakibara, Kimura)
- Today Yusuke (and Tomotada Akutsu) measure the vibration of the cryo duct.
- Cryocoolers (Tomaru, Suzuki)
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Eiichi contacted HPD and asked to give us a little more time. Eiichi promised to contact them in the summer, again. Eiichi think the president has kindly understood our situation.
- Takanori, Rahul, Ryutaro, and Eiichi are summarizing our work for a CQG article. The temporary title is 'Update on cryogenic sapphire mirror and its seismic attenuation system for KAGRA'. The deadline is the end of this month.
- Fabrication (PF, IM, IMR) (Tomaru):
- Kume-san introduces a company. They come KEK on the 2nd or 3rd of July for the meeting.
- Hagiwara-san (KEK) writes drawing based on Type B payload. You can check the latest version on wiki of KEK.
- Moving Mass (Chen, Tomaru):
- Although Takayuki is in his official trip, Suzuki-san and Hagiwara-san proceed. Some missing parts are prepared. Kazuhiro have already obtained quotations for drivers. After this meeting, he sent it to Suzuki-san.
- Recoil mass
- Sapphire Mirror (Hirose)
- A meeting with a vendor for manufacturing an Ergonomic-arm will be held on July 9. We may need to come up with a simpler and cheaper method due to lack of resources, though.
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Preparation for full size prototype is in progress. Dan is drawing ears and almost finished. Sascha will start soon to discuss with IMPEX about flat cut and ear.
- Kazuhiro is summarizing budget for sapphire suspension (not only sapphire parts but also assembly jigs and so on).
- Dan proceeds with measurement of Q of sapphire fiber at Rome. He will move to Jena tomorrow.
- Sascha and Kazuhiro exchange information every week.
- Test
Status of R&D (K. Yamamoto)
- Misc
2014.06.17
Management & Schedule (Suzuki)
- 大幅な予算削減が行われることになる。特推が使えるようになる。KEKで事務の準備が進んでいる。契約課からの発注。見積もりを鈴木経由で契約課へ。外国からの直接購入はしない。
- Kume-san supports to design of payload and so on. His authorship must be checked.
- Installation (Tomaru, Suzuki)
- Y end installation (transportation) will start on 18th of July. At least 2 persons must be at site to check status. They must stay within one week. Probably, Suzuki-san and Kimura-san ?
- Test of truck for vacuum pipes will be done; instead of these pipes, 12m cryo duct will be used.
- Car leasing must be prepared.
- Mirror Cryostat (Sakakibara, Kimura)
- Pipe for SAS : Discussion with Mechanical Engineering Center of KEK is in progress.
- Duct Shield (Sakakibara, Kimura)
- Heat transfer measurement is in progress.
- Cryocoolers (Tomaru, Suzuki)
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Chen, Tomaru):
- Recoil mass
- Sapphire Mirror (Hirose)
- CLIKでのサファイアサス試験の準備をひきつづき行っている
- アセンブリ確認用のアルミパーツ（ロッドとヘッド）を製作した。
- コイルアクチュエータ用ボビン、クランプなどは現在物性研工作室で製作中。
- コーティングQ値測定で使用していたCLIKが温まり次第、レイアウトを最終確認してフレームなどを発注する。
- Rahulが耳タイプのFEA計算をはじめた。（サイドフラット、耳、ヘッドはひっかけるタイプ）
- CLIKでのサファイアサス試験の準備をひきつづき行っている
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
Koike-san calculated deformation of sapphire bulk on Fe and Sn plate Slides(S. Koike). He takes flat cut on barrel surface of sapphire mirror into account. The result does not depend on the flat cut. In short, flat cut does not change stress distribution in sapphire bulk.
- Test
Status of R&D (K. Yamamoto)
- Misc
2014.06.10
Management & Schedule (Suzuki)
- 大幅な予算削減が行われることになる。
- Installation (Tomaru, Suzuki)
- Mirror Cryostat (Sakakibara, Kimura)
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki)
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Chen, Tomaru):
- Recoil mass
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Design of ears and flat cut is discussed.
- Test
Status of R&D (K. Yamamoto)
- Misc
- Ishizaki-san (on behalf of safety control office) would like to explain Hazard Analysis in this week (one or two weeks later).
2014.06.03
Management & Schedule (Suzuki)
- 大幅な予算削減が行われることになる。 内容の再考が必要。
- A drastic trimming of budget for Cryopayload will be happened.
- We have to reconsider items.
- Installation (Tomaru, Suzuki)
- Mirror Cryostat (Sakakibara, Kimura)
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki)
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Chen, Tomaru):
- Recoil mass
- Sapphire Mirror (Hirose)
- MIR
- ETM研磨は来年度に繰り越した
- CSIROと側面を円柱面で高精度に仕上げる方法について協議中
- タイプA設計
- プロトタイプ試験（信光社に依頼してあるブレード、TM、ロッドなどからなるシステム試験のこと）の準備をすすめている。フレーム、アクチュエータ（コイルボビンや磁石の選定）などの設計はほぼ終わり、ダイナミクスをモニターするための光の取り回しなどについて検討中。７月に試験開始予定。
- Rahulがパーツ間でのボンディングロスなどを考慮したモデルで解析をすすめている
- HPDとの件は財源を確保できるかどうか確認しないと話をすすめられないので現在ストップ。
- 関口くんがPF用縦ばねの詳細設計を先週おこなった。
- MIR
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Test
Status of R&D (K. Yamamoto)
2014.05.20
Management & Schedule (Suzuki)
- 大幅な予算削減が行われることになる。 内容の再考が必要。
- A drastic trimming of budget for Cryopayload will be happened.
- We have to reconsider items.
- Installation (Tomaru, Suzuki)
Design drawing of clean booth (CAD drawing for clean booth(Shinji Miyoki))
- Mirror Cryostat (Sakakibara, Kimura)
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki)
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Chen, Tomaru):
- Recoil mass
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Outlines and strategies of sapphire mirror suspension (final version) is discussed in the payload meeting.
- Test
Status of R&D (K. Yamamoto)
2014.05.13
Management & Schedule (Suzuki)
- 大幅な予算削減が行われることになる。（~41%） 内容の再考が必要。
- A drastic trimming of budget for Cryopayload will be happened.(~41% of the original)
- We have to reconsider items.
- Installation (Tomaru, Suzuki)
Available angles on optical windows: Optical windows 2 (T.Tomaru)
- Mirror Cryostat (Sakakibara, Kimura)
Radiation shield pipes for SAS holes: Shield Pipe SAS (T.Tomaru)
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki)
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Chen, Tomaru):
- Recoil mass
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Report about outlines of sapphire mirror suspension (final version) should be written as soon as possible.
- Test
Status of R&D (K. Yamamoto)
- Control systems are absolutely necessary and could be expensive. We will discuss this topic in the payload meeting.
- Misc (K. Yamamoto)
- Main closing item in A/I list
- (#080) Kazuhiro checks whether 80 cables can be along the metal wire between Bottom filter and Platform. You can check in his office by today.
(#109) Bending length of thick fibers. In progress. Bending length of thick fibers
(#112)Kazuhiro summarize memo(Japanese). He add figure to show requirements of each part in cryo payload.Cryogenic payload requirement(English).
- Main closing item in A/I list
2014.04.30
Management & Schedule (Suzuki)
- Installation (Tomaru, Suzuki)
- Mirror Cryostat (Sakakibara, Kimura)
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki)
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Chen, Tomaru):
- Recoil mass
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Report about outlines of sapphire mirror suspension (final version) should be written as soon as possible.
- Round polish or Flat cut ? : Round polish (and ears) must be expensive and risk in manufacturing mirror is smaller. On the contrary, the cost of flat cut is not extremely expensive (about 3000 Euro, IMPEX. Flat cut is far from reflective surface) and risk in manufacturing mirror is larger. The deadline of decision is in June. What kinds of information is necessary ?
- Round polish : Strength test of bonding (Yusuke asked quotation to Shinkosha ?)
- Flat cut : ?
- Test
Status of R&D (K. Yamamoto)
- Kazuhiro Yamamoto takes over the cryogenic test of metal blade spring in PF although Takahashi-san and Ishizaki-san still are in charge of design and procurement. Kazuhiro has some questions.
- When is the deadline of test ? End of June ?
- Size in total (Kazuhiro would like to check whether it can be put in 1/4 cryostat)
- Compensation system or something similar for vertical drift by cooling
- Kazuhiro Yamamoto takes over the cryogenic test of metal blade spring in PF although Takahashi-san and Ishizaki-san still are in charge of design and procurement. Kazuhiro has some questions.
- Misc (K. Yamamoto)
- Meeting for layout around vacuum chamber (2nd of May, Ando lab). Mainly, layout (of mortar) in the center room will be discussed. Somebody in CRY attends ?
- Safety : We must take care of it in installation phase. Ohishi-san would like to discuss this topic in this meeting near future.
- Fresh persons : Toyoda-san joins. He comes every Tuesday at least. Two new graduate students (Prof. Kajita) join the cryogenic experiments every Thursday and Friday although they could change their topics later.
2014.04.22
Management & Schedule (Suzuki)
- Installation (Tomaru, Suzuki)
- Mirror Cryostat (Sakakibara, Kimura)
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki)
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- 1) Finally Bill Hollander at HPD contacted me proposing a meeting in a couple of days.
- 2) Hirose visited Shinkosha to discuss ear configuration. I proposed a strength test with test pieces which is similar to what we have done at KEK. It is essentially a pulling test with R125 surfaces done by them. Yusuke made drawings and asked a quotation already.
- 3) Rahul is preparing models to predict performance of both cradle and ear configuration.
- 4) Vertical spring in PF: Takanori designed a prototype and we are asking Eric to review it and refine it.
- 5) Ryutaro is visiting Eric to discuss this.
- 6) Vertical spring test will be taken over by Kazuhiro?
- 7) Hirose will be absent due to attend a seminar in Tokyo.
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Chen, Tomaru):
- Recoil mass
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Test
Status of R&D (K. Yamamoto)
2014.04.15
Management & Schedule (Suzuki)
First kick-off meeting with MESCO for cryostat installation at Apr. 10 at Kamioka. Slides.
- Installation (Tomaru, Suzuki)
- Mirror Cryostat (Sakakibara, Kimura)
Original CAD sever: http://wiki.kek.jp/display/gw/Cryogenics+CAD
- Duct Shield (Sakakibara, Kimura)
- Cryocoolers (Tomaru, Suzuki)
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- 1) Planning to have a review meeting of vertical spring (date is not determined yet)
- 2) A quote came for a prototype ear from Shinkosha
- 3) No answer from HPD yet
- 4) Prototype test plan (cradle) was discussed yesterday (Yusuke uploaded minutes on archive). We need to prepare things before sapphire parts arrive. What we want to make clear are, verification of hanging, bounce mode frequency, mirror temperature with/without thermal input (~1W), fiver quality factor (comparison with independent measurement), to check dynamics of the mirror when pushing it with actuators and so on.
- 5) Trying to build a system model to study thermal noise.
- Fabrication (PF, IM, IMR) (Tomaru):
- Moving Mass (Chen, Tomaru):
- Recoil mass
- Sapphire Mirror (Hirose)
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto)
- Quotation for round polish was asked and we wait reply. We have quotation of flat cut.
- Test
Status of R&D (K. Yamamoto)
In the last cryo payload meeting, we picked up R&D items behind schedule Minutes(K. Yamamoto).
- What is the first priority ? What kinds of information are necessary for design ?
- Vertical metal spring : Temperature dependence of Young's modulus and resonant frequency. According to schedule, by the end of March, one blade spring cryogenic test and triple blades procurement are finished.But actually, not yet. Triple blades must be prepared soon.
- Heat links : Measurement of thermal resistance at end of heat link. The result affect the number of heat links. Layout (geometry must be symmetric).
- Control : Test for stepping motor and thrust bearing. Active damping system. Coil magnet actuator. Sizes of these systems are necessary for design (how accurate ?).
- Baffle and Auxiliary Optics Subsystem (Akutsu)
2014.04.07
Management & Schedule (Suzuki)
- First kick-off meeting with MESCO for cryostat installation at Apr. 10 at Kamioka. We will discuss about installation schedule of the end cryostats.
- Installation (Tomaru, Suzuki)
- Mirror Cryostat (Sakakibara, Kimura)
- Duct Shield (Sakakibara, Kimura)
- We will release a specification document of duct shield in this week. Three duct shield will be fabricated in this FY.
- Cryocoolers (Tomaru, Suzuki)
- We will release a specification document of first three low-vibration cryocoolers for the duct shields in this week. Now we discuss about the cost of one-stage pulse-tube cryocoolers with the cryocooler company since they are under considering the price down of the PTC. If the price is acceptable, we will not chose solvey cryocoolers but chose PTCs.
- Room temperature SAS (Sekiguchi, Takahashi)
- Cryo-Payload
- Heat link (Sakakibara)
- Design (PF, IM, IMR) (Hirose, Sekiguchi, Rahul, Takahashi)
- A remote meeting was held on March 28th.
- HPD gave us a quote for moving mass for PF and IM, and torsion adjustment
- We gave them links to room-temperature VIS. They are looking into them to figure out an estimate for preparing necessary drawings for the modification.
- We ordered sapphire parts for the cradle configuration to Shinkosha.
- We would like to propose for an ear configuration (will explain it today). I asked a quotation about the ear to Shinkosha.
- Rahul is preparing models for ANSYS.
- Takanori is looking into control issues (sensors and actuators)
- Takahashi-san started a cryogenic bade test
- Need to prepare a solid test plan for the system (installation, strength, heat conductivity, controllability, and so on)
Fabrication (PF, IM, IMR) (Tomaru): Suzuki-san and I had meeting with Mitaka-koki Co. for Cryo-pendulum fabrication. They have interesting in our cryo-payload fabrication and accepted the style that they fabricate the payload with R&D with us.
- Moving Mass (Chen, Tomaru): I got stepping motor which can work at cryogenic temperature but it didn't have driver. Can we get it?
- Recoil mass
- Sapphire Mirror (Hirose)
- Contracts for FY2014 are in preparation.
- Sapphire Mirror Suspension (Chen, Sascha, Yamamoto) Yesterday, we discussed the strategy. Fiber nail head is hooked by blade spring which is similar to that from Shinkosha. For comparison, we must collect quotations for flat cut or round polish.
- Test
- Baffle and Auxiliary Optics Subsystem (Akutsu)
- Location of a wide-angle baffle should be discussed.
- Interface parts between a wide-angle baffle and a cryo-duct shield should be discussed.
- Non-arm side, i.e. btwn BS-ITM, we need to consider the way to control stray light; as a reference, there are no baffles are installed closed to the ITM side in LIGO so far, but around BS, there is a baffle.
- The recoil mass of the ITMs/ETMs should have also a function of baffle. Let's consider about it.