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KAGRA Vacuum System. 130801 VAC (YS). 1. Layout (interferometer and survey map) ** tilting the optical plane of interferometer for draining water. ** horizontal floors in each room prepared for installing chambers.
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KAGRA Vacuum System 130801 VAC (YS) • 1. Layout (interferometer and survey map) • **tilting the optical plane of interferometer • for draining water. • **horizontal floors in each room prepared for installing chambers. • **position of chamber/mirror is to be described in “map coordinates (survey map) of tunnel” EYC EYV Xopt EYA horizontal plane at X end Y-arm optical plane of interferometer X arm x IYA IYC IYV y O (BS) horizontal plane at center room MC Yopt PRM BS X-arm Y arm horizontal plane at Y end IXC IXV IXA EXA EXC EXV SRM
KAGRA Vacuum System 130801 VAC (YS) 1. Layout (KAGRA location) Geodetic coordinates: Latitude, Longitude, Height (B, L, H+He) H; radius of GRS80 of ellipsoid earth Hg; height of geoid surface from GRS80 surface Z Xmap Japan rectangular plane coordinate: survey map (Xmap, Ymap, Ho) Ymap Takayama origin, zone VII, Japan Ho: height from geoid surface B 3D terrestrial coordinate: KAGRA optical plane (X, Y, Z) He (ellipsoid height) = Ho(orthometric height) + Hg (geoid height) Y H X L • GRS80
KAGRA Vacuum System 130801 VAC (YS) 2. Optical baffles in beam tubes • Number of baffles in the 3-km long arm • Every 24-m, or longer, along the arm, 40-mm in height, 54-degree tilted • Requirement: baffle surface (coating) • Specular reflection <10% @1064 nm,0-60 deg incidence • Total scattering <2% @1064, 12deg incidence • Surface roughness Ra <several microns or less • Mechanical and thermal durability (film) • Flexural strength of plated film: JIS H8504 • Thermal shock strength: JIS H8504 • Friction proof: JIS H8503 • Vacuum performance • Outgassing rate <3x10-7 Pa m3 s-1m-2
KAGRA Vacuum System 130801 VAC (YS) 2. Optical baffles in beam tubes Structure PCD = φ810 R h = (D-d)/2 = 40 mm θ= 36° D=798 d=720 w
KAGRA Vacuum System 130801 VAC (YS) 2. Optical baffles in beam tubes Manufacturing process • 1) Stainless steel sheet (SUS304 BA) of 0.8 mm thick • 2) Laser cutting for sector shape andserrated edge • 3) Rolling and welding for conicalshape(frustum) • 4) Removing oxidized layer of weld beads • 5) “Solblack” plating • alkaline degreasing • electrolytic cleaning • acid cleaning • Ni plating (5 mm) • Solblack plating (15 mm) • chemical treatment for blacking • thermal treatment (190°C 2.5hrs, in air) • 6) Vacuum firing (220-250°C 4hrs, in vacuum)
KAGRA Vacuum System 130801 VAC (YS) 2. Optical baffles in beam tubes Manufacturing process • 1) Stainless steel sheet (SUS304 BA) of 1 mm thick • 2) Laser cutting for sector shape andserrated edge • 3) Rolling and welding for conicalshape(frustum) • 4) Removing oxidized layer of weld beads • 5) “Solblack” plating • alkaline degreasing • electrolytic cleaning • acid cleaning • Ni plating (5 mm) • Solblack plating (15 mm) • chemical treatment for blacking • thermal treatment (190°C 2.5hrs, in air) • 6) Vacuum firing (220-250°C 4hrs, in vacuum)
KAGRA Vacuum System 130801 VAC (YS) 2. Optical baffles in beam tubes • Properties of “solblack coating” • Specular reflection <10% @1064 nm,0-60 deg incidence • Total scattering <2% @1064, 12deg incidence • Surface roughness Ra <several microns or less • Mechanical and thermal durability (film) • Flexural strength of plated film: JIS H8504 • Thermal shock strength: JIS H8504 • Friction proof: JIS H8503 • Vacuum performance • Outgassing rate <3x10-7 Pa m3 s-1m-2
KAGRA Vacuum System 130801 VAC (YS) 2. Optical baffles in beam tubes • Properties of “solblack coating” • Specular reflection <10% @1064 nm,0-60 deg incidence • Total scattering <2% @1064, 12deg incidence • Surface roughness Ra <several microns or less • Mechanical and thermal durability (film) • Flexural strength of plated film: JIS H8504 • Thermal shock strength: JIS H8504 • Friction proof: JIS H8503 • Vacuum performance • Outgassing rate <3x10-7 Pa m3 s-1m-2 Total scattering including specular reflection @ 8 deg incidence
KAGRA Vacuum System 130801 VAC (YS) 2. Optical baffles in beam tubes • Properties of “solblack coating” • Specular reflection <10% @1064 nm,0-60 deg incidence • Total scattering <2% @1064, 12deg incidence • Surface roughness Ra <several microns or less • Mechanical and thermal durability (film) • Flexural strength of plated film: JIS H8504 • Thermal shock strength: JIS H8504 • Friction proof: JIS H8503 • Vacuum performance • Outgassing rate <3x10-7 Pa m3 s-1m-2
KAGRA Vacuum System 130801 VAC (YS) 2. Optical baffles in beam tubes • Properties of “solblack coating” • Specular reflection <10% @1064 nm,0-60 deg incidence • Total scattering <2% @1064, 12deg incidence • Surface roughness Ra <several microns or less • Mechanical and thermal durability (film) • Flexural strength of plated film: JIS H8504 • Thermal shock strength: JIS H8504 • Friction proof: JIS H8503 • Vacuum performance • Outgassing rate <3x10-7 Pa m3 s-1m-2 solblack: after vacuum baking