A5039514479- Particle Accelerators and Free-Electron Lasers
- Pulsars and Gravitational Waves Research
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Geophysics and Sensor Technology
- Advanced X-ray Imaging Techniques
- Geophysics and Gravity Measurements
- Seismic Waves and Analysis
- Photocathodes and Microchannel Plates
- Advanced Frequency and Time Standards
- Adaptive optics and wavefront sensing
- Gyrotron and Vacuum Electronics Research
- Advancements in Photolithography Techniques
- Magnetic confinement fusion research
- SAS software applications and methods
- Cold Atom Physics and Bose-Einstein Condensates
- High-pressure geophysics and materials
- Astronomical Observations and Instrumentation
- Atomic and Subatomic Physics Research
- Astrophysical Phenomena and Observations
- Radiation Therapy and Dosimetry
- Fusion materials and technologies
- Dark Matter and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Hand Gesture Recognition Systems
High Energy Accelerator Research Organization
2013-2024
The University of Tokyo
2005-2022
Kavli Institute for the Physics and Mathematics of the Universe
2022
National Institutes for Quantum Science and Technology
2019
Intelligent Systems Research (United States)
2015
Aichi Science & Technology Foundation
2014
Nagoya University
2014
Nagoya University Hospital
2014
Institute for Cosmic Ray Research
2014
Nagoya Industrial Science Research Institute
2014
TAMA300, an interferometric gravitational-wave detector with 300-m baseline length, has been developed and operated sufficient sensitivity to detect events within our galaxy stability for observations; the interferometer was over 10 hours stably continuously. With a strain-equivalent noise level of $h\ensuremath{\sim}5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}21}/\sqrt{\mathrm{Hz}}$, signal-to-noise ratio 30 is expected gravitational waves generated by coalescence...
We analyzed 6 hours of data from the TAMA300 detector by matched filtering, searching for gravitational waves inspiraling compact binaries. incorporated a two-step hierarchical search strategy in filtering. obtained an upper limit 0.59/hour (C.L.=90%) on event rate inspirals binaries with mass between 0.3M⊙ and 10M⊙ signal-to-noise ratio greater than 7.2. The distance 1.4M⊙(0.5M⊙) which produce 7.2 was estimated to be 6.2 kpc (2.9 kpc) when position source sky inclination angle were...
A laser strainmeter with a 1500-m baseline was constructed at an underground site in Kamioka, Gifu Prefecture, Japan, and has been operating since August 2016. The interferometer measures the change distance between two retroreflectors housed vacuum chambers separation of 1500 m. are fixed to ground tunnel KAGRA gravitational wave telescope. high-frequency-stabilized is used as light source; it achieves Allan variance 3 × 10−13. Since operations began, motions large amplitude timescale...
In the data obtained by laser interferometric gravitational wave detectors, transient noise with non-stationary and non-Gaussian features occurs at a high rate. This often results in problems such as detector instability hiding and/or imitation of gravitational-wave signals. has various characteristics time-frequency representation, which is considered to be associated environmental instrumental origins. Classification can offer clues for exploring its origin improving performance detector....
It is well known that a negative electron affinity GaAs photocathode shows moderate temporal response when excited by laser pulse of wavelength close to its band gap energy. We show here the can be estimated using diffusion model describes internal transport conduction electrons. Using transverse deflection cavity system, we measured profile bunch generated DC gun illuminated ps pulsed laser. A systematic set measurements cathodes with various active layer thicknesses and boundary conditions...
We report the reduction of thermal lensing in cryogenic sapphire mirrors, which are planned to be used large scale gravitational wave telescope project. measured three key parameters substrate for at temperature. They optical absorption coefficient, conductivity and temperature coefficient refractive index On basis these measurements, we estimated shot noise sensitivity interferometer with by using a wavefront tracing simulation. found that mirrors is negligible.
Operational experience of a 500 kV photoemission gun at the compact energy recovery linac (cERL) High Energy Accelerator Research Organization is presented. The gun, developed Japan Atomic Agency, was found to have failures in two out ten-segment ceramic insulator just after installation cERL. had been operated 390 with eight segments until April 2015 and provided 0.9 mA beam. An additional two-segment installed on top existing insulators recover high-voltage performance. then conditioned up...
Current status of TAMA and CLIO detectors in Japan is reported this article.These two interferometric gravitational-wave are being developed for the large cryogenic gravitational wave telescope (LCGT) which a future plan detecting signals at least once per year.TAMA300 upgraded to improve sensitivity low frequency region after last observation experiment 2004.To reduce seismic noises, we installing new isolation system, called Seismic Attenuation System, four test masses.We confirmed stable...
The objective of the TAMA 300 interferometer was to develop advanced technologies for kilometre scale interferometers and observe gravitational wave events in nearby galaxies. It designed as a power-recycled Fabry–Perot–Michelson intended step towards final Japan.
Interferometric gravitational wave detectors require a large degree of vibration isolation. For this purpose, multilayer stack constructed rubber and metal blocks is suitable, because it provides isolation in all degrees freedom at once. In TAMA300, 300 m interferometer Japan, long-term dimensional stability compatibility with an ultrahigh vacuum environment about 10−6 Pa are also required. To keep the its operating point despite ground strain thermal drift system, actuator was introduced....
Laser frequency stabilization is essential for interferometric gravitational-wave detectors to attain their target sensitivity. We have designed a multistage laser system which has been applied in the development of TAMA 300 detector Japan. The control topology consisting two cascaded loops were employed secure high feedback gain and reliable operation thus allow best stability uninterrupted long-term observation. achieved simultaneously 5×10−5 Hz/Hz, common-mode rejection ratio (which...
A negative electron affinity GaAs photocathode source is characterized by high brightness, quantum efficiency, and a moderate temporal response. The initial emittance depends on the mean transverse energy (MTE) of electrons cathode surface. We evaluated MTE based measurements obtained using waist scan method with three types cathodes: bulk GaAs, thickness-controlled samples active-layer thicknesses 100 1000 nm, GaAs/GaAsP superlattice sample. dependence laser wavelength, thickness active...
KAGRA is a laser interferometric gravitational-wave detector with 3 km arm length. It to be constructed in the tunnels of Kamioka mine Hida, Gifu, Japan. The use an underground site for small seismic motion key feature KAGRA, as well cryogenic technique reduce any thermal noise. will have total length 7697 m and volume 156 301 . Tunnel excavation work began May 2012, continued until end March 2014. construction experiment rooms currently ongoing, installation vacuum system was planned begin...
On the stochastic gravitational-wave search, correlated noise in two or more detectors can be a serious problem. Schumann resonance is name of standing wave electromagnetic fields, which one sources for second-generation detectors. We measured levels environmental magnetic field both inside and outside mine KAGRA site at Kamioka. In this letter, we report result measurement compare amplitude fields to find possible issues gain constructing detector underground.
In interferometric cryogenic gravitational wave detectors, there are plans to cool mirrors and their suspension systems (payloads) in order reduce thermal noise, that is, one of the fundamental noise sources. Because large payload masses (several hundred kg total) isolation, a cooling time several months is required. Our calculation shows high-emissivity coating (e.g. diamond-like carbon (DLC) coating) can effectively by enhancing radiation heat transfer. Here, we have experimentally...
The mid-infrared range is an important spectrum where materials exhibit a characteristic response corresponding to their molecular structure. A free-electron laser (FEL) promising candidate for high-power light source with wavelength tunability investigate the nonlinear of materials. Although self-amplification spontaneous emission (SASE) scheme not usually adopted in range, it may have advantages such as layout simplicity, possibility producing single pulse, and scalability short-wavelength...
We have developed a novel absolute distance meter (ADM) for determining coseismic strain steps and analysed far-field crustal deformation caused by earthquakes. By measuring the optical resonant frequency of 100-m-long cavity in relation to an accurate time standard, can be determined with resolution 2 × (10−9–10−10); measurements ensure detection changes before after earthquake, even when encountering large seismic waves that often hinder relative measurements. The proposed system,...
With a low emittance and short-bunch electron beam at high repetition rate realized by superconducting linac, stimulated excitation of an optical cavity the terahertz spectrum range is shown. The passes through small holes in mirrors without being destroyed. A sharp resonance structure which indicates wideband emission via coherent diffraction radiation observed while scanning round-trip length cavity.
The Japanese gravitational wave observatory KAGRA will be operated at cryogenic temperatures to reduce thermal noise. Four main mirrors and their suspension systems, called payloads, cooled in the cryostat. Vibrations of cryostat cryocooler can contaminate output detector. One noise paths is heat link made from pure soft metal between payload cryocoolers cool payload. In order evaluate this amplitude, we measured vibration radiation shield production site Yokohama, Japan. For measurement,...