・Ground vibration・Low vibration environment・Gravitational wave observation device・Vibration measuring instrument MRA-06X (OSP-06, MG-102S, RS1)

As part of the Japan Vibration Technology Association (JAVIT) domestic non-vibration ground survey project, CLIO: Cryogenic Laser Interferometer observatory (CLIO: Cryogenic Laser Interferometer observatory) is located at 1000 m underground in Hida City/Kamioka Mine, Gifu Prefecture. ) Installation floor vibration environment was measured. CLIO was built as a prototype facility of the so-called KAGRA (official name LCGT plan, laser interferometer with a baseline length of 3 km below 200 m underground of the Kamioka mine) scheduled to start full-scale observation from 2019 to 2020. (CLIO has a baseline length of 100 m). Gravitational waves are wave phenomena in which space-time distortion that occurs when an object with a mass moves is transmitted at the speed of light.The detection of gravitational waves is expected to verify general relativity and clarify various cosmic phenomena. Has been done. (TAMA300 (National Astronomical Observatory), for which we have taken active anti-vibration measures in the past, also corresponds to the predecessor project of this plan. The KAGRA construction plan has begun as a more sensitive observation facility.) Very small to detect gravitational waves A vibrating environment is required and such a place was chosen as the construction site. In this example, we will introduce the vibration data actually measured at this location.

Servo-type acceleration sensor (patented device: MG-102s): 3 units Low-frequency vibrometer (patented device: OSP-06): 1 unit Data logger (patented device: RS1): 1 set ■ Servo-type acceleration sensor MG-102S Main Specifications ・Measuring range: ±17m/s2 ・Minimum resolution: 1×10-6m/s2 ・External dimensions: 40×40×55.5mm ・Mass: 190g

As shown in the figure below, it was confirmed that the environment is an ultra-low vibration that shows the lower limit level of our vibration measurement system (MRA-06X) in almost all areas below 100 Hz. Normally, it is extremely rare that the ground is on the ground, and the environment is such that the microvibration environment is present over all frequencies, which was valuable measurement data.