BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:The latest development in ALFRA\, the UWA low-frequency rotational
  accelerometer
DTSTART;VALUE=DATE-TIME:20220524T133500Z
DTEND;VALUE=DATE-TIME:20220524T135500Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4837@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Ammar Al-Jodah (The University of Western Australia)
 \nGround rotation sensors at low-frequency have a vital role in improving 
 seismic isolation systems in advanced and 3G gravitational wave detectors.
  It was found that using seismometers as the sole source of ground motion 
 measurement results in undistinguishable motion detection between horizont
 al and tilt motion\, especially below 100 mHz. Therefore\, pure angular mo
 tion measurement is necessary to separate tilt and translation to be appli
 ed as feedback in active isolation control. ALFRA is a low-frequency rotat
 ional accelerometer developed at the University of Western Australia (UWA)
  to detect ground tilt motion. It is a compact\, inertial reference style 
 rotation sensor that can be mounted in three orientations to detect ground
  tilt around a different axis of interest. A preliminary study of a protot
 ype showed that ALFRA can achieve high readout sensitivity of few nrad/√
 Hz above 20 mHz and 0.1 nrad/√Hz above 50 mHz in measuring ground tilt. 
 In this work\, we will present our latest design for ALFRA and highlight s
 everal improvements that will be added to our previous design to enhance s
 everal aspects of the sensor and increase its sensitivity\, usability\, an
 d convenience of adjustment.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/25
 5/contributions/4837/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4837/
END:VEVENT
BEGIN:VEVENT
SUMMARY:E-TEST: A Compact Isolation Concept for Future Einstein Telescope
DTSTART;VALUE=DATE-TIME:20220524T143500Z
DTEND;VALUE=DATE-TIME:20220524T145500Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4898@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: AMEER SIDER (Precision Mechatronics Laboratory\, Uni
 versité de Liège\, B-4000 Liège\, Belgium)\nThis study presents a low f
 requency isolation system in the framework of E-TEST project which is a re
 search facility for Einstein Telescope. The isolation system combines a pa
 ssive inverted pendulum and an active inertial platform. The design of thi
 s isolator allows reducing the overall height of the isolation system. We 
 address the isolation system design\, its dynamics and the control strateg
 y applied. The simulation results show that the seismic noise could succes
 sfully be reduced by about 3 orders of magnitude at 1 Hz in horizontal whe
 n the control is applied. To avoid spoiling the performance at high freque
 ncy\, the inertial platform is designed in such a way that the first flexi
 ble internal mode appears above 300 Hz.\n\nhttps://indico.icrr.u-tokyo.ac.
 jp/event/255/contributions/4898/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4898/
END:VEVENT
BEGIN:VEVENT
SUMMARY:New Generation Superattenuators for Einstein Telescope
DTSTART;VALUE=DATE-TIME:20220524T141500Z
DTEND;VALUE=DATE-TIME:20220524T143500Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4840@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Lucia Trozzo (Istituto Nazionale di Fisica Nucleare)
 \nSeismic noise and local disturbances are dominant noise below 10 Hz (0.1
 -10 Hz).With the introduction of high performance seismic isolation system
 s based on mechanical pendula\,the 2nd generation GW antennas have reached
  the scientific goal of the direct observation of GW signals thanks to the
  extension of the frequency band down to 10 Hz. Now\,the 3rd generation in
 strument era is approaching and the Einstein Telescope giant interferomete
 r is becoming a reality with the possibility to install the detector in an
  underground site where seismic noise is 100 times smaller then on surface
 . Moreover\,new available technologies and the experience acquired in oper
 ating advanced detectors are key points to further extend the detection ba
 ndwidth down to 2-3 Hz with the possibility to suspend cryogenic payload a
 nd then mitigating Thermal Noise too.In this talk\, we present the prelimi
 nary studies devoted to improve seismic attenuation performance of the Adv
 anced VIRGO Superattenuator in the low frequency region.Following the expe
 rimental lines\,we analyze the possibility to improve the vertical attenua
 tion performance with a multistage pendulum chain equipped with magnetic a
 nti-springs that is hung to a double Inverted Pendulum in nested configura
 tion.The feedback control requirements and the possible strategies to be a
 dopted for this last element\, will be presented.\n\nhttps://indico.icrr.u
 -tokyo.ac.jp/event/255/contributions/4840/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4840/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Update on sensing seismic platform relative motion using Digital I
 nterferometry
DTSTART;VALUE=DATE-TIME:20220524T135500Z
DTEND;VALUE=DATE-TIME:20220524T141500Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4838@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Sheon Chua (ANU Centre for Gravitational Astrophysic
 s - OzGrav)\nThe relative motion of seismic platforms\, via coupling to th
 e auxiliary length controls of the suspended optics\, are predicted to be 
 the limiting noise source for future gravitational-wave detectors at frequ
 encies below 1 Hz. By measuring\, then stabilizing this relative motion\, 
 the effective control feedback to the optics will be reduced and hence the
  noise coupling will be less\, and potentially improve detector noise perf
 ormance. The measurement of the relative motion with forms of suspension p
 latform interferometry is an ongoing area of interest and research. Digita
 lly-enhanced Interferometry is a decade-mature technique for sensing relat
 ive motion\, by providing time-tagged pseudorandom phase modulation to iso
 late signals based on time-of-flight delay. The application of digitally-e
 nhanced interferometry for suspension sensing is an active area of develop
 ment within the Newtonian Noise research program at the Australian Nationa
 l University\, and offers another potential method for sensing relative pl
 atform motion. We present an update on recent developments of digitally-en
 hanced interferometry towards suspension sensing and measurement.\n\nhttps
 ://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4838/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4838/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Introduction
DTSTART;VALUE=DATE-TIME:20220524T133000Z
DTEND;VALUE=DATE-TIME:20220524T133500Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4843@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Joris  van Heijningen (UCLouvain)\nhttps://indico.ic
 rr.u-tokyo.ac.jp/event/255/contributions/4843/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4843/
END:VEVENT
BEGIN:VEVENT
SUMMARY:GWADW2023
DTSTART;VALUE=DATE-TIME:20220527T144000Z
DTEND;VALUE=DATE-TIME:20220527T145500Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4761@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4761
 /
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4761/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Panel discussions
DTSTART;VALUE=DATE-TIME:20220527T141000Z
DTEND;VALUE=DATE-TIME:20220527T144000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4760@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4760
 /
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4760/
END:VEVENT
BEGIN:VEVENT
SUMMARY:ET at 3 Hz - can we break the 'controls noise' wall?
DTSTART;VALUE=DATE-TIME:20220527T133000Z
DTEND;VALUE=DATE-TIME:20220527T135000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4879@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Conor Mow-Lowry (Nikhef)\nThe Einstein Telescope aim
 s to have astrophysically interesting \nsensitivity at 3Hz. The performanc
 e goal is a factor of ~10^6 quieter \nthan LIGO and Virgo at that frequenc
 y. This talk will present a recipe \nfor addressing controls noise in a sy
 stematic manner at the design stage \nwith supporting evidence from existi
 ng instruments.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contributio
 ns/4879/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4879/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Angled beam expander telescopes for the Michelson beams in third g
 eneration Gravitational Wave Observatories
DTSTART;VALUE=DATE-TIME:20220524T043000Z
DTEND;VALUE=DATE-TIME:20220524T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4856@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Third generation of Gravitational Wave detectors like the Eins
 tein Telescope or the\nCosmic Explorer will be Michelson interferometers w
 ith Fabry-Perot cavities in the arms\,\nusing mirror test masses with diam
 eter at the limit of technical feasibility. Unlike other\ndetectors\, the 
 Einstein Telescope will have a 60° angle between the arms. Because of its
 \nlarger incidence angle\, at any given beam size\, it would require beam 
 splitters almost double\nin size and much heavier than the 90° case. It i
 s proposed here to install beam expander\ntelescopes with angled mirrors l
 ocated inside the Michelson interferometer between the\nFabry-Perot caviti
 es and the beam splitter. Beyond reducing the beam sizes and the\nbeam spl
 itter to manageable sizes\, the proposed solution allows to bring the opti
 mal\nrecombination angle to 90°. The proposed geometry offers a natural w
 ay to separate the\nbeam splitters of different detectors into individual\
 , smaller and more stable caverns\, thus\nimproving observatory observatio
 n-time efficiency\, to provide needed beam diagnostic\npoints and convenie
 nt degrees of freedom for beam alignment into both the Fabry-Perot\ncaviti
 es and the beam splitter\, as well as to provide a method for maintaining 
 optimal mode\nmatching of the two arms onto the beam splitter without ther
 mal compensation plates.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/255/co
 ntributions/4856/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4856/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Compensating decoherence of squeezed light in cavity-enhanced quan
 tum metrology
DTSTART;VALUE=DATE-TIME:20220527T043000Z
DTEND;VALUE=DATE-TIME:20220527T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4783@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Quantum states of light are being more commonly used to increa
 se the sensitivity of various sensors. They allow to reach high sensitivit
 y without using significant light power\, and thus find application in var
 ious fields\, from biological sensing to gravitational-wave detection. At 
 the same time\, these states are very fragile\, and even a small amount of
  decoherence can significantly reduce their benefit. We propose a new appr
 oach that allows to compensate part of quantum decoherence\, thus increasi
 ng the sensitivity beyond the previously established decoherence-induced q
 uantum limit. To achieve this\, we use an optimally tuned quantum squeezer
  placed directly inside the detector cavity. This squeezer operates to res
 tore the externally injected squeezing or to amplify the signal\, dependin
 g on the level of loss. It can be flexibly tuned to the optimal operation.
  We present the first experimental combination of intra-cavity and externa
 lly injected squeezing used to enhance detector’s sensitivity. We demons
 trate for the first time how optimal tuning allows to compensate quantum d
 ecoherence. Finally\, we derive the new decoherence-induced quantum limit.
  Based on this approach\, we develop the quantum expander for the detectio
 n bandwidth of GW detectors\, which allows to significantly increase the s
 ensitivity at high frequencies.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event
 /255/contributions/4783/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4783/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Juggled interferometer for gravitational wave detection
DTSTART;VALUE=DATE-TIME:20220527T043000Z
DTEND;VALUE=DATE-TIME:20220527T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4784@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Juggled interferometer (JIFO) is a novel type of earthbound gr
 avitational wave detector targeting a frequency band of 0.1–10 Hz. By us
 ing repeatedly free-falling test masses\, JIFO can in principle decouple t
 est masses from the seismically noisy environment and avoid suspension the
 rmal noise in a straightforward manner. Since the test masses are in a wei
 ghtless state\, as is the case with space gravitational wave detectors\, J
 IFO would be a good testbed for technologies of space projects. \n\nHere\,
  the concept of the Michelson-type JIFO is introduced. Then the experiment
  setup and the data readout method of a JIFO are discussed. Considering th
 e displacement noise budget of the Einstein Telescope (ET)\, we show that 
 the juggled test masses could significantly improve the sensitivity at 0.1
 -2.5 Hz even with discontinuous data. The science cases brought with the i
 mproved sensitivity would include detecting quasi-normal modes of black ho
 les with 104-105 Msun\, testing Brans-Dicke theory with black-hole and neu
 tron-star inspirals\, and detecting primordial-black-hole-related gravitat
 ional waves.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contributions/
 4784/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4784/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SpicyPy: a common python tool for signal processing and control sy
 stems
DTSTART;VALUE=DATE-TIME:20220527T043000Z
DTEND;VALUE=DATE-TIME:20220527T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4785@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Within gravitational wave research community (including but no
 t limited to LIGO-Virgo-KAGRA\, Einstein Telescope and LISA collaborations
 ) a lot of work in understanding and improving the detectors involves sign
 al processing and modelling of control systems. Historically\, different s
 oftware tools were used for these purposes. We believe that it is possible
  to create a single software tool that can be useful for many different ap
 plications in these domains. This would help to facilitate exchange of kno
 wledge between collaborations\, and could be used in teaching.\n\nWe aim t
 o develop a python package intended as a general tool with a simple but po
 werful interface to facilitate control systems modelling\, signal processi
 ng\, and provide an interface between the two. It may rely on other well-k
 nown and tested packages already used for these applications\, but it will
  abstract interactions with them with a unified interface. Potential appli
 cations include time series analysis\, suspensions modelling\, feeding sen
 sor signals through a control system\, and more. The project is a collabor
 ative open-source effort across the groups from the start\, and new contri
 butors are always welcome. We are currently focused on compiling software 
 requirements specification and are in discussions with researches from dif
 ferent collaborations to understand the most common potential applications
 .\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4785/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4785/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Substrate transferred aluminum gallium arsenide (AlGaAs) crystalli
 ne coatings
DTSTART;VALUE=DATE-TIME:20220527T043000Z
DTEND;VALUE=DATE-TIME:20220527T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4788@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Substrate-transferred crystalline coatings made from aluminum 
 gallium arsenide (AlGaAs) have very low thermal noise compared to the ion 
 beam deposited amorphous oxides used until now in gravitational wave detec
 tors.  AlGaAs coatings also show excellent optical properties and both the
 rmal noise and optical performance has been demonstrated in other precisio
 n optics applications.  The primary challenge to using AlGaAs coatings in 
 future detectors is the coating diameter necessary and the large mass and 
 thickness of the test mases.  We present results on 10 cm diameter AlGaAs 
 coatings and propose multiple pathways to implement AlGaAs coatings on upg
 rades to current detectors with up to 40 kg masses and on future detectors
  with larger masses. We also show schedule and budget plans that allow AlG
 aAs to be used in future gravitational wave detectors.\n\nhttps://indico.i
 crr.u-tokyo.ac.jp/event/255/contributions/4788/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4788/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Optical absorption of TiO$_{2}$ doped SiO$_{2}$ as a replacement h
 igh index coating material
DTSTART;VALUE=DATE-TIME:20220527T043000Z
DTEND;VALUE=DATE-TIME:20220527T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4808@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:The sensitivity of 3rd generation gravitational wave detectors
  is currently projected to be\nlimited by the level of Brownian coating th
 ermal noise produced from highly reflecting\nmirror coatings.  In the curr
 ent detectors layers of Ta$_2$O$_5$\, a material with higher\nrefractive i
 ndex (n = 2.14)\, has higher levels of optical absorption compared the low
 er index\nlayers of SiO$_ {2}$ (n=1.44). To improve detector sensitivity a
 nd duty cycle\, the optical and\nmechanical properties of new doped coatin
 g materials are being investigated. This work\npresents measurements of th
 e optical absorption of SiO$_2$ and SiO$_2$ doped with\nTiO$_2$ layers as 
 part of a highly reflecting coating stack. Utilising the photothermal\ncom
 mon-path interferometry technique\, we discuss the effects of heat treatme
 nt and\ncrystallisation on the optical performance of the material compare
 d to current aLIGO \ncoatings.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/
 255/contributions/4808/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4808/
END:VEVENT
BEGIN:VEVENT
SUMMARY:TiO$_{2}$:SiO$_{2}$ coating thermal noise and optical studies
DTSTART;VALUE=DATE-TIME:20220527T043000Z
DTEND;VALUE=DATE-TIME:20220527T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4809@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Current gravitational wave detectors are limited in their most
  sensitive frequency range by the mirror coating thermal noise which arise
 s from the Brownian motion of the coating materials on the interferometer 
 test mass optics. For the next generation detector upgrades and beyond\, i
 t is imperative to find coating materials/topologies that reduce this mech
 anical effect\, whilst still meeting the desired optical requirements.  Ti
 tania-doped silica had been identified as a coating material candidate whi
 ch could potentially improve detector sensitivity. \n\nWe present here our
  investigations into the mechanical and optical properties of highly-refle
 ctive coating stacks made of pure SiO2 and TiO2 doped SiO2\, deposited via
  ion beam sputtering (IBS). Two different concentrations of TiO2 doping in
  the high-refractive index layers of our coating stacks were investigated\
 , with mechanical loss and optical absorption being measured through diffe
 rent steps of heat treatment for each\, with the level of coating thermal 
 noise being calculated from the former.\n\nhttps://indico.icrr.u-tokyo.ac.
 jp/event/255/contributions/4809/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4809/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Angular Signal Amplification with a Coupled Cavity for Torsion-Bar
  Antenna
DTSTART;VALUE=DATE-TIME:20220527T043000Z
DTEND;VALUE=DATE-TIME:20220527T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4851@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Torsion-Bar Antenna (TOBA) is a ground-based gravitational wav
 e detector using a torsion pendulum. The resonant frequency of torsional m
 otion is ~1 mHz\, therefore TOBA has good design sensitivity of $10^{-19} 
 \\\, / \\sqrt{\\mathrm{Hz}}$ at 0.1 Hz in low frequencies (0.1 Hz – 10 H
 z). TOBA can detect intermediate mass black hole binary mergers\, Newtonia
 n noise\, and so on. A prototype detector Phase-III TOBA with a 35 cm-scal
 e pendulum is under development to demonstrate noise reduction. The target
  sensitivity is set to $10^{-15} \\\, / \\sqrt{\\mathrm{Hz}}$ at 0.1 Hz. T
 o achieve our target sensitivity\, we need to measure the pendulum rotatio
 n precisely. We propose a coupled wavefront sensor (Coupled WFS) as an ang
 ular sensor for Phase-III TOBA. In our method\, an auxiliary cavity is use
 d to compensate Gouy phase of a main cavity and enhance the first-order TE
 M modes in the main cavity. The experimental demonstration was successfull
 y performed in 2021. In this workshop\, we will show the principle and dem
 onstration results of a Coupled WFS.\n\nhttps://indico.icrr.u-tokyo.ac.jp/
 event/255/contributions/4851/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4851/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Estimating the Newtonian noise of groundwater at the KAGRA
DTSTART;VALUE=DATE-TIME:20220527T043000Z
DTEND;VALUE=DATE-TIME:20220527T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4854@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Changes due to gravitational waves are very small\, so noise i
 s generated due to various factors. KAGRA was built 300 meters underground
  to reduce ground vibrations. The groundwater generated underground is dis
 charged through pipes. The gravity gradient generated by the universal gra
 vitation force due to the oscillation of the water surface through the pip
 e may cause the mirror of KAGRA to shake and become a noise to the target 
 sensitivity of KAGRA. \nOur experiment was conducted using the simulation 
 software Flow-3D in order to know the magnitude of Newtonian noise. The Ne
 wtonian noise was evaluated by calculating the waveform of the flowing wat
 er.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4854/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4854/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Control of Dual-Pass Fabry-Perot Cavity for space gravitational wa
 ve antennas : DECIGO and B-DECIGO
DTSTART;VALUE=DATE-TIME:20220527T043000Z
DTEND;VALUE=DATE-TIME:20220527T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4855@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:A dual-pass Fabry-Perot cavity will be used for DECIGO (DECi-h
 ertz Interferometer Gravitational-wave observatory) and B-DECIGO. To detec
 t gravitational waves\, it is necessary to establish the method to control
  the dual-pass Fabry-Perot cavity. We can divide this issue in two parts\,
  “Length control” and “Alignment control”. For Length control\, it
  is demonstrated that we can control the length of dual-pass Fabry Perot c
 avity with Pound-Drever-Hall technique. On the other hand\, for Alignment 
 control\, though the method was already proposed (WaveFront Sensor and Bea
 m Pointing Control)\, it is not demonstrated yet. Therefore\, an experimen
 t is needed for the demonstration.In this poster\, we show the principle t
 o control the dual-pass Fabry-Perot cavity in the direction of the angle a
 nd explain the experiment to demonstrate it.\n\nhttps://indico.icrr.u-toky
 o.ac.jp/event/255/contributions/4855/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4855/
END:VEVENT
BEGIN:VEVENT
SUMMARY:CO2 mode cleaner for Thermal Compensation System of Advanced Virgo
 +
DTSTART;VALUE=DATE-TIME:20220527T043000Z
DTEND;VALUE=DATE-TIME:20220527T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4846@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:As planned for its fifth observation run O5\, Advanced Virgo+ 
 will have 80 Watts in main laser. The absorption of laser power in the int
 erferometer's core optics leads to thermal effects causing optical aberrat
 ions\, ultimately preventing interferometer's operation. To recover detect
 or's ideal operation\, Thermal Compensation System (TCS) is needed to corr
 ect wavefront distortions. In particular\, to correct the axisymmetric par
 t of the spurious thermal lens in the power recycling cavity\, a heating p
 attern is projected on a compensation plate using Double Axicon System (DA
 S) where a 50 Watts CO2 laser beam is reshaped using axicons.  Due to O5 s
 tringent requirements on the residual of DAS correction\, heating pattern 
 distortions caused by the known amount of higher-order modes (HOM) in the 
 CO2 beam cannot be tolerated. To remove these HOMs\, we are constructing a
 n optical mode cleaner which will allow us to retain 95% of the CO2 laser 
 power for compensation with a strong reduction of HOM related residual cor
 rection. To our knowledge\, this is the first time a mode cleaner is desig
 ned for a high power CO2 laser. We present here the requirements\, motivat
 ion and current status of the work\, discussing the issues related to the 
 CO2 wavelength and power.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/255/c
 ontributions/4846/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4846/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vibration analysis of ETpathfinder cryogenic heat-links
DTSTART;VALUE=DATE-TIME:20220527T043000Z
DTEND;VALUE=DATE-TIME:20220527T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4819@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:The Einstein Telescope pathfinder (ETpathfinder) is a cryogeni
 c testbed for the next generation of gravitational-waves antennas. To reac
 h the target temperature of 18 K\, ETpathfinder cryogenic payloads are des
 igned to extract heat from the test masses by integrating low stiffness an
 d highly conductive heat-links that connect to the cryocoolers. Since the 
 interferometer test masses are very sensitive to mechanical vibrations\, t
 he noise from the cryocoolers through the heat conductor should be careful
 ly monitored and controlled. This work presents the modeling and experimen
 tal measurements of the mechanical vibrations transferred by the heat-link
 s in a dedicated payload setup. To investigate the stability criterion of 
 the cold-head\, seismic noise propagated via the heat-links is then projec
 ted to the displacement sensitivity of ETpathfinder.\n\nhttps://indico.icr
 r.u-tokyo.ac.jp/event/255/contributions/4819/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4819/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Measuring thermal noise in gram-scale Si flexures at 123 K
DTSTART;VALUE=DATE-TIME:20220527T043000Z
DTEND;VALUE=DATE-TIME:20220527T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4817@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Future terrestrial gravitational wave detectors are limited by
  fundamental noise sources\, one of which is the thermal noise arising in 
 the test masses and suspensions in the frequency band where ground-based d
 etectors are sensitive. To mitigate this noise\, future detectors are envi
 sioned to operate at cryogenic temperatures using silicon optics as test m
 asses and silicon ribbons to suspend the test masses. Silicon ribbons rese
 mble cantilever topology\, and therefore studying the thermal noise in the
  flexing of a gram-scale silicon cantilever is analogous to the suspension
  thermal noise encountered in these ribbon suspensions. At the Australian 
 National University\, I have built an operational cryogenic infrastructure
  to measure the broadband thermal noise of silicon flexures at 123 K. In t
 his talk\, I will present initial results of our cool-down tests\, thermal
  noise measurements from the experiment and future plans.\n\nhttps://indic
 o.icrr.u-tokyo.ac.jp/event/255/contributions/4817/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4817/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vibration Analysis of KAGRA Cryostat at Cryogenic Temperature
DTSTART;VALUE=DATE-TIME:20220527T043000Z
DTEND;VALUE=DATE-TIME:20220527T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4810@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Large-scale Cryogenic Gravitational-Wave Telescope\, KAGRA is 
 a second-generation gravitational-wave detector (GWD) located in Japan. Th
 e features that distinguish KAGRA from other GWDs are its underground loca
 tion and cryogenic operation of the four main mirrors. The underground loc
 ation provides a quiet site with low seismic noise\, while the cryogenic o
 peration cools the mirrors down to 20 K\, reducing the thermal noises. How
 ever\, cryocooler vibration and structural resonances of the cryostat can 
 contaminate detector sensitivity as they couple to test mass through the h
 eat-links. Monitoring and characterization of the vibration inside the cry
 ostat is critical for the optimum noise performance of KAGRA. \nIn April\,
  2020 KAGRA conducted an international observation run\, "O3GK" along with
  GEO600. During this run several noise sources were identified and a noise
  budget was prepared.  However\, as the mirrors were not cooled the noise 
 transfer via heat-links was estimated based on room temperature\, in vacuu
 m vibration measurement performed 2.5 years before O3GK. During the upcomi
 ng observation run the mirrors will be cooled down\, so we performed vibra
 tion analysis of the cooling system at cryogenic temperature to study its 
 impact on detector sensitivity. In this poster\, we describe the KAGRA coo
 ling system and discuss the results of vibration analysis.\n\nhttps://indi
 co.icrr.u-tokyo.ac.jp/event/255/contributions/4810/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4810/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Optimization of design parameters for Gravitational Wave detector 
 DECIGO including fundamental noises
DTSTART;VALUE=DATE-TIME:20220524T043000Z
DTEND;VALUE=DATE-TIME:20220524T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4777@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:The DECi-hertz Interferometer Gravitational-Wave Observatory (
 DECIGO) is a space gravitational wave (GW) detector. DECIGO was originally
  designed to be sensitive enough to observe primordial GW background (PGW)
 . However\, due to the lowered upper limit of the PGW by the Planck observ
 ation\, further improvement of the target sensitivity of DECIGO is require
 d. In the previous studies\, DECIGO’s parameters were optimized to maxim
 ize the signal-to-noise ratio (SNR) of the PGW to quantum noise including 
 the effect of diffraction loss. To simulate the SNR more realistically\, w
 e optimize DECIGO’s parameters considering the GWs from double white dwa
 rfs (DWDs) and the thermal noise of test masses. We consider two cases of 
 the cutoff frequency of GWs from DWDs. In addition\, we consider two kinds
  of thermal noise: thermal noise in a residual gas and internal thermal no
 ise. To investigate how the mirror geometry affects the sensitivity\, we c
 alculate it by changing the mirror mass and thickness. As a result\, we ob
 tained the optimums for the parameters that maximize the SNR that depends 
 on the mirror radius. This result shows that a thick mirror with a large r
 adius gives a good SNR and enables us to optimize the design of DECIGO.\n\
 nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4777/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4777/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Probing dipole radiation with the low-frequency gravitational-wave
  observatories
DTSTART;VALUE=DATE-TIME:20220524T043000Z
DTEND;VALUE=DATE-TIME:20220524T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4778@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Atom-interferometer gravitational-wave (GW) observatory\, as a
  new design of ground-based GW detector for the near future\, is sensitive
  at a relatively low frequency for GW observations. Taking the proposed at
 om interferometer Zhaoshan Long-baseline Atom Interferometer Gravitation A
 ntenna (ZAIGA)\, and its illustrative upgrade (Z+) as examples\, we invest
 igate how the atom interferometer will complement ground-based laser inter
 ferometers in testing the gravitational dipole radiation from binary neutr
 on star (BNS) mergers. A test of such kind is important for a better under
 standing of the strong equivalence principle laying at the heart of Einste
 in's general relativity. To obtain a statistically sound result\, we sampl
 e BNS systems according to their merger rate and population\, from which w
 e study the expected bounds on the parameterized dipole radiation paramete
 r $B$. Extracting BNS parameters and the dipole radiation from the combina
 tion of ground-based laser interferometers and the atom-interferometer ZAI
 GA/Z+\, we are entitled to obtain tighter bounds on $B$ by a few times to 
 a few orders of magnitude\, compared to ground-based laser interferometers
  alone\, ultimately reaching the levels of $|B| \n\nhttps://indico.icrr.u-
 tokyo.ac.jp/event/255/contributions/4778/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4778/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Prospects for Detecting Exoplanets around Double White Dwarfs with
  LISA and Taiji
DTSTART;VALUE=DATE-TIME:20220524T043000Z
DTEND;VALUE=DATE-TIME:20220524T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4780@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Recently\, Tamanini & Danielski discussed the possibility of d
 etecting circumbinary exoplanets (CBPs) orbiting double white dwarfs (DWDs
 ) with the Laser Interferometer Space Antenna (LISA). Extending their meth
 ods and criteria\, we discuss the prospects for detecting exoplanets aroun
 d DWDs not only by LISA\, but also by Taiji\, a Chinese space-borne gravit
 ational-wave (GW) mission. We first explore how different binary masses an
 d mass ratios affect the abilities of LISA and Taiji to detect CBPs. Secon
 d\, for certain known detached DWDs with high signal-to-noise ratios\, we 
 quantify the possibility of CBP detections around them. Third\, based on t
 he DWD population obtained from the Mock LISA Data Challenge\, we present 
 basic assessments of the CBP detections in our Galaxy during a 4 yr missio
 n time for LISA and Taiji. We discuss the constraints on the detectable zo
 ne of each system. With the DWD population\, we further inject two differe
 nt planet distributions with an occurrence rate of 50% and constrain the t
 otal detection rates. We briefly discuss the prospects for detecting habit
 able CBPs around DWDs with a simplified model. These results can provide h
 elpful inputs for upcoming exoplanetary projects and help analyze planetar
 y systems after the common envelope phase.\n\nhttps://indico.icrr.u-tokyo.
 ac.jp/event/255/contributions/4780/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4780/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Realistic Detection and Early Warning of Binary Neutron Stars with
  Decihertz Gravitational-wave Observatories
DTSTART;VALUE=DATE-TIME:20220524T043000Z
DTEND;VALUE=DATE-TIME:20220524T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4781@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:We investigated the detection and localization of binary neutr
 on star (BNS) populations with decihertz gravitational-wave observatories 
 in a realistic detecting strategy\, including real-time observations and e
 arly warnings. Assuming 4 years' operation of B-DECIGO\, we found that the
  detected BNSs can be divided into three categories: (a) sources that merg
 e within 1 year\, which could be localized with an uncertainty of $\\Delta
 \\Omega \\sim 10^{0}$deg$^2$\;  (b) sources that merge in 1-4 years\, whic
 h take up three quarters of the total events and yield the most precise an
 gular resolution with $\\Delta \\Omega\\sim 10^{-2}$deg$^2$ and time-of-me
 rger accuracy with $\\Delta t_c\\sim 10^{-1}$s\; and (c) sources that do n
 ot merge during the 4-yr mission window\, which enable possible early warn
 ings\, with $\\Delta \\Omega\\sim 10^{-1}$deg$^2$ and $\\Delta t_c\\sim 10
 ^{0}$s. Furthermore\, we compared the pros and cons of B-DECIGO with the E
 instein Telescope\, and explored the prospects of detections using 3 other
  decihertz observatories and 4 BNS population models. In realistic observi
 ng scenarios\, we found that decihertz detectors could even provide early-
 warning alerts to a source decades before its merger while their localizat
 ions are still more accurate than ground-based facilities.\n\nhttps://indi
 co.icrr.u-tokyo.ac.jp/event/255/contributions/4781/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4781/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Space gravitational wave antenna DECIGO
DTSTART;VALUE=DATE-TIME:20220524T043000Z
DTEND;VALUE=DATE-TIME:20220524T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4782@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:DECi-hertz Interferometer Gravitational-wave Observatory (DECI
 GO) is a future Japanese space gravitational-wave antenna with a frequency
  band of 0.1 Hz to 10 Hz. DECIGO aims at detection of primordial gravitati
 onal waves\, which could have been produced during the inflationary period
  right after the birth of the universe. There are many other scientific ob
 jectives of DECIGO\, including the direct measurement of the acceleration 
 of the expansion of the universe\, and reliable and accurate predictions o
 f the timing and locations of neutron star/black hole binary coalescences.
  DECIGO consists of four clusters of observatories placed in the heliocent
 ric orbit. Each cluster consists of three spacecraft\, which form three di
 fferential Fabry-Perot interferometers with an arm length of 1\,000 km. Th
 ree clusters of DECIGO will be placed far from each other\, and the fourth
  cluster will be placed in the same position as one of the three clusters 
 to obtain the correlation signals for the detection of the primordial grav
 itational waves. In this presentation\, we will explain the aimed sciences
 \, the mechanical and optical design\, and the current status of DECIGO.\n
 \nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4782/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4782/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Space GW Antenna B-DECIGO
DTSTART;VALUE=DATE-TIME:20220524T043000Z
DTEND;VALUE=DATE-TIME:20220524T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4805@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:B-DECIGO is a space gravitational wave antenna mission. While 
 it is a precursor mission of DECIGO\, we can expect fruitful sciences with
  B-DECIGO. One of the most exciting science cases is detection of compact 
 binary system before merger. It will enlarge the possibility of multi-mess
 enger astronomy with electro-magnetic wave observations at the time of mer
 ger. In this presentation \, we will review the science cases and mission 
 concept of B-DECIGO.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contri
 butions/4805/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4805/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Localization of gravitational waves using machine learning
DTSTART;VALUE=DATE-TIME:20220524T043000Z
DTEND;VALUE=DATE-TIME:20220524T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4807@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:An observation of gravitational waves is a trigger of the mult
 i-messenger search of an astronomical event. A combination of the data fro
 m two or three gravitational wave detectors indicates the location of a so
 urce and low-latency data analysis is key to transferring the information 
 to other detectors sensitive at different wavelengths. In contrast to the 
 current method\, which relies on the matched-filtering technique\, we prop
 osed the use of machine learning that is much faster and possibly more acc
 urate than matched filtering. \nOur machine-learning method is a combinati
 on of the method proposed by Chatterjee *et al.* and a method using the te
 mporal convolutional network.\nWe demonstrate the sky localization of a gr
 avitational-wave source using four detectors: LIGO H1\, LIGO L1\, Virgo\, 
 and KAGRA\, and compare the result in the case without KAGRA to examine th
 e positive influence of having the fourth detector in the global gravitati
 onal-wave network.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contribu
 tions/4807/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4807/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Practical quantum noise estimate of optical-spring quantum locking
  for space gravitational wave detector DECIGO
DTSTART;VALUE=DATE-TIME:20220524T043000Z
DTEND;VALUE=DATE-TIME:20220524T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4818@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:The DECi-hertz Interferometer for Gravitational-wave Observato
 ry(DECIGO) aims mainly at the detection of primordial gravitational waves 
 (PGWs) originating from inflation. Recent observations by the Planck satel
 lite and others have lowered the upper limit of PGWs. Thus\, it is necessa
 ry to improve the target sensitivity of DECIGO. A newly proposed method to
  reduce the quantum noise of DECIGO is quantum locking with an optical spr
 ing. In this method\, a short cavity is added to the main cavity\, sharing
  one mirror of both cavities. The error signal in this auxiliary cavity is
  obtained properly in a homodyne detection\, and fed back to the shared mi
 rror to cancel the radiation pressure noise of the main cavity. In our pre
 vious study\, the optimal sensitivity assuming ideal homodyne detection wi
 thout any additional noise was obtained by simulation. In this study\, we 
 investigate a more realistic design\, taking into account the mixture of t
 he vacuum fluctuations incident to the homodyne detection system. In this 
 poster\, we explain the latest results of this investigation\n\nhttps://in
 dico.icrr.u-tokyo.ac.jp/event/255/contributions/4818/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4818/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The Sar-Grav Laboratory at the Sos Enattos site\, one of the quiet
 est site in the 2-10 Hz frequency range
DTSTART;VALUE=DATE-TIME:20220524T043000Z
DTEND;VALUE=DATE-TIME:20220524T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4847@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Einstein Telescope (ET) will be the third generation of gravit
 ational wave interferometer to be built in Europe. One of the sites candid
 ates to host ET is located in Sardinia (Italy)\, near the Sos Enattos mine
 \, where a seismometer’s net already proves the quietness of the site. T
 he Sar-Grav laboratory\, a seed of ET\, aims to host underground experimen
 ts\, cryogenic payloads\, low frequency and cryogenic sensor development t
 hat need low seismic and anthropogenic noise. On the surface there are a h
 angar of about 900 square meters\, an optical laboratory and a control roo
 m\; a 20 tons crane and cleaned rooms are planned to be installed. Undergr
 ound\, an area of 250 square meters and small experimental areas are plann
 ed to be built\, while different stations at different depths are hosting 
 sensors like seismometers and magnetometers. A fundamental physics experim
 ent\, Archimedes\, is under installation in the surface area and will be m
 oved underground in the future.\nThe site will host the test of the prelim
 inary seismic isolation system\, currently under studies \, that will be d
 esigned to improve seismic attenuation in the low frequency region (0.1-10
  Hz) and reduce the frequency of mechanical resonances.\n\nhttps://indico.
 icrr.u-tokyo.ac.jp/event/255/contributions/4847/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4847/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gravitational wave sources in the low frequency region and their d
 istances
DTSTART;VALUE=DATE-TIME:20220524T043000Z
DTEND;VALUE=DATE-TIME:20220524T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4849@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Pulsars are expected to be strong sources of low frequency gra
 vitational waves in ground based interferometers. The knowledge of their d
 istances is a key parameter to estimate the gravitational emission. The pu
 lsar distances are usually estimated using dispersion measure. The Gaia da
 ta release provides information on the distance\, kinematic and photometri
 c properties of nearly two billions astronomical sources\, among them some
  pulsars and accreting neutron star systems.\nThe Gaia based distances of 
 some systems relevant for gravitational astronomy will be discussed.\n\nht
 tps://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4849/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4849/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The Current Status of TOrsion-Bar Antenna (TOBA) Experiment
DTSTART;VALUE=DATE-TIME:20220524T043000Z
DTEND;VALUE=DATE-TIME:20220524T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4850@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Torsion-bar antenna (TOBA) is a ground-based gravity gradiomet
 er proposed for measurement of gravity gradient fluctuations such as gravi
 tational waves and gravity gradient noise. TOBA consists of two perpendicu
 lar torsion pendulum\, and the low mechanical resonant frequency of torsio
 n pendulums enables us to measure gravity gradient of frequencies around 0
 .1 Hz. TOBA aims to achieve the sensitivity 10^(-19) / √Hz at 0.1 Hz. \n
 For the final sensitivity goal we are developing a prototype Phase-III TOB
 A in order to investigate technical issues and establish noise reduction s
 cheme. One of the key topic of Phase-III TOBA is cryogenic suspension syst
 em for the reduction of the thermal noise. Another key point is the readou
 t system with monolithic interferometer. We will show the current situatio
 n of the developments and future upgrade plans for further improvement.\n\
 nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4850/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4850/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Displacement-noise-free neutron interferometer for gravitational w
 ave detection at low frequencies
DTSTART;VALUE=DATE-TIME:20220524T043000Z
DTEND;VALUE=DATE-TIME:20220524T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4852@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Improvement of the sensitivity of gravitational-waves (GWs) de
 tectors at lower frequencies is still challenging on account of displaceme
 nt noise sources\, such as thermal noise\, seismic noise\, and radiation p
 ressure noise. One of the solutions is the displacement-noise-free interfe
 rometer (DFI). At frequencies lower than 1Hz\, however\, the DFI has less 
 sensitivity to GWs because the propagation time of light is much shorter t
 han the period of the GWs. To resolve this problem\, DFI with neutrons ins
 tead of laser\, which is called a neutron DFI\, was proposed. In a neutron
  DFI with neutrons propagating much more slowly than light\, the neutron p
 ropagation time can be comparable to the period of GWs at lower frequencie
 s. This enables us to cancel displacement noise without cancellation of th
 e GW signals. Also\, we proposed a simplification of the detector configur
 ation by taking advantage of the ability to adjust the neutron speeds depe
 nding on the configuration. In our poster\, we discuss the principle of th
 e neutron DFI as well as a plan of the demonstration experiment.\n\nhttps:
 //indico.icrr.u-tokyo.ac.jp/event/255/contributions/4852/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4852/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Current Status of Quantum Locking Experiment for Space Gravitation
 al Wave Antenna DECIGO
DTSTART;VALUE=DATE-TIME:20220524T043000Z
DTEND;VALUE=DATE-TIME:20220524T063000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4853@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:The DECi-hertz Interferometer Gravitational wave Observatory (
 DECIGO) is the future Japanese space mission with 1\,000 km arm cavities. 
 One of the main objectives of DECIGO is the detection of primordial gravit
 ational waves (PGWs) produced in the inflation period. We should improve D
 ECIGO’s target sensitivity\, which is limited by quantum noise\, to enha
 nce the possibility of the detection of PGWs.\n\nThe standard squeezing te
 chniques to reduce the quantum noise are not effective because of the larg
 e diffraction loss in DECIGO due to the long arm length. Therefore\, we pr
 oposed a new method\, quantum locking with an optical spring\, to reduce t
 he quantum noise in a relatively broad frequency band. Quantum locking is 
 the technique\, in which each mirror of the long arm cavity (main cavity) 
 is shared by two short-arm cavities (sub-cavities). Then the sub-cavities 
 control the mirrors’ motion of the main cavity. Interferometer signals o
 btained from the main cavity and the two sub-cavities can be combined to o
 ptimize the sensitivity of DECIGO.\n\nIn parallel with the theoretical ana
 lysis of the technique\, we have been performing the experiment to verify 
 the principle of the theory. In this poster session\, we explain the curre
 nt status of the quantum locking experiment.\n\nhttps://indico.icrr.u-toky
 o.ac.jp/event/255/contributions/4853/
LOCATION:GatherTown and ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4853/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sapphire suspension in KAGRA –Current design and perspective-
DTSTART;VALUE=DATE-TIME:20220526T043000Z
DTEND;VALUE=DATE-TIME:20220526T045000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4814@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Takafumi Ushiba (ICRR)\nCooling mirrors and their su
 spensions are promising way to reduce thermal noise. To maximize the benef
 its of cooling\, utilizing low mechanical loss material at cryogenic tempe
 rature is essential\; therefore\, KAGRA mirrors and their suspension fiber
 s are made of sapphire. To achieve good cryogenic suspension\, there are s
 everal technical difficulties because the suspension needs not only low me
 chanical loss for thermal noise reduction but also high thermal conductivi
 ty for keeping mirror temperature low. In this talk\, we present a review 
 of the current KAGRA sapphire suspension and its perspective.\n\nhttps://i
 ndico.icrr.u-tokyo.ac.jp/event/255/contributions/4814/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4814/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sapphire technology for cryogenic detectors: new results from Lyon
DTSTART;VALUE=DATE-TIME:20220526T063000Z
DTEND;VALUE=DATE-TIME:20220526T065000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4821@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Teo Aventin (iLM)\nThe institutes iLM and iP2i in Ly
 on are involved on a significant effort to develop the sapphire technology
  for the future cryogenic detectors. iLM is taking care of the crystalline
  growth of ultra-low level of optical absorption and mechanical losses of 
 mirror substrates and last stage suspensions. iP2i through the platform LM
 A develops the ultra-low level of total optical losses of mirrors\, workin
 g on aberration\, scattering and absorption. The collaboration is finalisi
 ng the development of a large oven able to grow 500kg sapphire ingots for 
 the production of 450mm diameter mirrors. In parallel the investigation on
  the growth of ultra-low absorption sapphire is ongoing and the details on
  the most recent result of 10ppm/cm sapphire will be presented. The impact
  that this new advancement will have on the ET suspensions will be given t
 oo.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4821/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4821/
END:VEVENT
BEGIN:VEVENT
SUMMARY:AdV+ low frequency noises challenges and plans
DTSTART;VALUE=DATE-TIME:20220523T055500Z
DTEND;VALUE=DATE-TIME:20220523T061500Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4806@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Michal Was (LAPP/CNRS)\nAdvanced Virgo Plus is a two
  step plan for improving the sensitivity\nof Advanced Virgo for the O4 and
  O5 observing runs. After discussing\nthe low frequency noises that have l
 imited AdV in O3\, we will present\nthe planned AdV+ upgrades and adjustme
 nts that aim at reducing the low\nfrequency fundamental and technical nois
 es for O4 and O5.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contribut
 ions/4806/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4806/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A new approach for suspending cryogenic mirrors
DTSTART;VALUE=DATE-TIME:20220526T055000Z
DTEND;VALUE=DATE-TIME:20220526T061000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4786@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Francesca Badaracco (UCLouvain)\nThe Einstein Telesc
 ope will increase the sensitivity to gravitational wave detections with re
 spect to the current detectors\, especially in the low-frequency band (dow
 n to 2 Hz). Reaching such sensitivities at low frequencies implies great t
 echnology challenges: in order to reduce the seismic and the thermal noise
  very soft suspensions and cryogenic temperatures are needed. A big challe
 nge arises here: to bring and to keep a test mass at temperatures around 1
 0 K we need to extract heat from it. The only way to do this is via therma
 l conductivity of the test mass suspension elements. However\, soft suspen
 sions are non-compatible with the need of extracting heat which would requ
 ire short suspensions with a large cross section. We propose here a new su
 spension morphology in order to allow a good heat extraction without spoil
 ing the softness of the suspensions. This should provide a good solution t
 o one of the biggest technological problems of building the Einstein Teles
 cope.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4786/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4786/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Silicon suspensions: thermal noise and mechanical properties
DTSTART;VALUE=DATE-TIME:20220526T051000Z
DTEND;VALUE=DATE-TIME:20220526T053000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4789@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Flavio Travasso (University of Camerino - INFN Perug
 ia)\nThe design of cryogenic suspensions for mass tests for future generat
 ion GW detectors is based on the balancing of several factors: mechanical 
 properties\, thermal conductivity\, resonance frequencies\, thermo-mechani
 cal stress and generally any parameter that aims to reduce thermal noise o
 f test masses. The talk will present the state of the art of studying the 
 mechanical and thermal properties of silicon as a function of the orientat
 ion of the axes and how these can influence the design of a monolithic sus
 pension. Furthermore\, the measurements of the limit load on fibers produc
 ed at the maximum of the current technique will be described and compared 
 with the expected limit load\, trying to understand the limiting factors. 
 Finally\, we will describe the tests done so far to measure the mechanical
  dissipations of the mono-crystalline silicon fibers and the limits found.
 \n\nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4789/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4789/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thermal and mechanical simulation of the cryo-payload: status and 
 preliminary results.
DTSTART;VALUE=DATE-TIME:20220526T053000Z
DTEND;VALUE=DATE-TIME:20220526T055000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4787@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Paola Puppo (INFN Roma)\nIn the design of the cryoge
 nic payload\, thermal and mechanical FEA models are used for optimizing th
 e system both for its structural and thermal behavior. The thermal study i
 s important to have the temperature distribution along the suspension wire
 s and the thermal resistances of to the various interconnections between t
 he parts of the suspension. The mechanical study gives the estimation of t
 he losses present in the system. We will present the status of this combin
 ed method to have an estimation of the suspension thermal noise with the L
 evin method.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contributions/
 4787/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4787/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Review of LIGO's LF workshop
DTSTART;VALUE=DATE-TIME:20220523T153000Z
DTEND;VALUE=DATE-TIME:20220523T160000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4773@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Peter Fritschel (MIT)\nhttps://indico.icrr.u-tokyo.a
 c.jp/event/255/contributions/4773/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4773/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Approaches to low frequency noise in LIGO
DTSTART;VALUE=DATE-TIME:20220523T053500Z
DTEND;VALUE=DATE-TIME:20220523T055500Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4772@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Lee McCuller (Caltech)\nThis talk will overview the 
 current views of low frequency noise contributions in LIGO. This overview 
 provides context to discuss potential upgrade options either to reduce dir
 ect noise contributions or to address underlying causes of complex bilinea
 r noises.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contributions/477
 2/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4772/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cosmic Explorer at low frequency
DTSTART;VALUE=DATE-TIME:20220527T135000Z
DTEND;VALUE=DATE-TIME:20220527T141000Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4759@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Evan Hall ()\nThis talk will discuss the problems th
 at must be solved to achieve Cosmic Explorer's low frequency sensitivity g
 oals.\n\nhttps://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4759/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4759/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Multi-messenger observations of gravitational-wave transients
DTSTART;VALUE=DATE-TIME:20220523T051500Z
DTEND;VALUE=DATE-TIME:20220523T053500Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4682@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Alessandra Corsi (Texas Tech University)\nStarting f
 rom the example of GW170817\, I will discuss prospects for multi-messenger
  gravitational-wave astronomy\, highlighting opportunities to clarify curr
 ently open questions in the field\, while expanding multi-messenger studie
 s beyond the realm of compact binary mergers.\n\nhttps://indico.icrr.u-tok
 yo.ac.jp/event/255/contributions/4682/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4682/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Observing  black holes throughout the Universe
DTSTART;VALUE=DATE-TIME:20220523T043500Z
DTEND;VALUE=DATE-TIME:20220523T045500Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4681@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Colpi Monica (University of Milano Bicocca)\nI will 
 overview how extending detector sensitivities at low gravitational wave fr
 equencies will let us observe the first merging stellar black holes formin
 g at cosmic dawn\, and unveil the still elusive population of intermediate
 -mass black holes\, which provides clues on the yet unknown  origins of th
 e massive black holes lurking at the centres of today's galaxies.\n\nhttps
 ://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4681/
LOCATION:ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4681/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Introduction of the meeting
DTSTART;VALUE=DATE-TIME:20220523T043000Z
DTEND;VALUE=DATE-TIME:20220523T043500Z
DTSTAMP;VALUE=DATE-TIME:20260512T220152Z
UID:indico-contribution-255-4677@indico.icrr.u-tokyo.ac.jp
DESCRIPTION:Speakers: Kentaro Somiya (Tokyo Institute of Technology)\nhttp
 s://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4677/
LOCATION:ZOOM ZOOM
URL:https://indico.icrr.u-tokyo.ac.jp/event/255/contributions/4677/
END:VEVENT
END:VCALENDAR