Optical absorption in commercial single mode optical fibers
Optical absorption in commercial single mode optical fibers for the LHC machine T. Wijnands†, L. K. De Jonge†, J. Kuhnhenn‡, S. K. Hoeffgen‡, U. Weinand‡ †CERN, TS Department ‡ Fraunhofer INT Euskirchen Germany 6 th LHC Radiation Workshop : 29 -30 November 2007 CERN 4 September 2007 https: //webh 11. cern. ch/radworkshop/Registration. htm TWEPP 2007 - Prague
Radiation levels in the LHC IR 3 : Momentum Cleaning IR 7 : Betatron Cleaning 4 September 2007 TWEPP 2007 - Prague 2
Optical fibers in Collimation areas 4 September 2007 TWEPP 2007 - Prague 3
Fiber architecture LHC Point 7 600 m 132 m 4 September 2007 168 m TWEPP 2007 - Prague 4
MC simulations collimation area IR 7 RR 77 UJ 76 RR 73 Dose rate distributions along the tunnel in Gy/year 4 September 2007 TWEPP 2007 - Prague 1 LHC year = 200 days 5
Engineering Constraints for fibers • SM radiation hard optical fibers – RIA < 10 d. B/km after 100 k. Gy – 1310 nm – High Energy Physics radiation field • • Fibers in cables – cables to be blown Commercial manufacturer Series production ~3000 km Lead time ~1. 5 years 4 September 2007 TWEPP 2007 - Prague 6
Standard LHC optical fibers • Ge-P doped SM fiber – MCVD produced – Draka NK Cables Ltd. – 85/125 mm • Ge-doped SM fiber – PCVD produced – Draka Fiber Tech. BV – 85/125 mm Co-60 Irradiation (CEA-Saclay) 4 September 2007 TWEPP 2007 - Prague 7
Co-60 irradiation of standard LHC optical fibers Ge-doped no irradiation Ge-P doped Co-60 1 k. Gy/hr Co-60 500 Gy/hr no irradiation 4 September 2007 TWEPP 2007 - Prague 8
Radiation Induced Absorption V conductance band Ec color defects hn Photon Ev V=0 x=0 valence band 4 September 2007 x=L y(r, t)=Aei(kr-wt) TWEPP 2007 - Prague 9
Paramagnetic color defects 218 nm 630 nm 163 nm 660 nm 760 nm 630 nm 4 September 2007 TWEPP 2007 - Prague 10
Attenuation spectrum irradiated SM fibers 4 September 2007 TWEPP 2007 - Prague 11
From literature studies & experience • Radhard SM fibers (? ) for long wavelengths – Pure Silica Core (PSC) – Fluorine doped – Low OH content Neutron irradiation ? 4 September 2007 TWEPP 2007 - Prague 12
Screening test- sample collection • • • Fiberware Fujikura Ltd Japan Heraeus J-plasma Nufern Oxford Electronics Sumitomo Verillon Corning J-fiber Draka 4 September 2007 TWEPP 2007 - Prague 13
Screening test at Fraunhofer INT 4 September 2007 TWEPP 2007 - Prague 14
Radiation Induced attenuation 4 September 2007 TWEPP 2007 - Prague 15
Standard Ge-doped SM fiber 4 September 2007 TWEPP 2007 - Prague 16
Radiation hard F-doped fiber 4 September 2007 TWEPP 2007 - Prague 17
High Energy Physics irradiation test at CERN 4 September 2007 TWEPP 2007 - Prague 18
LHC Radiation Test Facility (TCC 2) 4 September 2007 TWEPP 2007 - Prague 19
High Energy Physics Radiation field 4 September 2007 TWEPP 2007 - Prague 20
High Energy Physics vs Co-60 4 September 2007 TWEPP 2007 - Prague 21
Related press releases London, 17 th April 2007 CERN Selects Fujikura’s Radiation Resistant Fibre to provide communications links within world’s largest particle accelerator Fujikura today announced that its radiation resistant single mode optical fibre has been selected by CERN, the European Laboratory for Particle Physics, to provide communication links within the world’s largest particle accelerator – the Large Hadron Collider (LHC) – near Geneva, Switzerland. Fujikura will supply 2, 500 km of fibre to collect beam instrumentation data from the LHC. To provide reliable communications, the fibre must be able to withstand localised radiation levels of up to 20 k. Gy/year – enough to cause radiation-induced attenuation in normal optical fibre. Fujikura Future. Guide® - RR, Radiation Resistant optical fibre Fiber resists CERN's radiation to carry data 2 May 2007 A radiation-resistant fiber is soon to be used in the world's largest particle accelerator for essential communication links. A radiation-resistant, single-mode optical fiber developed by Fujikura has been selected by CERN for essential communication links within the world's largest particle accelerator - the Large Hadron Collider (LHC). CERN Selects Fujikura`s Radiation Resistant Fibre 04/19/2007 Fujikura Ltd. announced that its radiation resistant single mode optical fibre has been selected by CERN to provide communication links within the world's largest particle accelerator - the Large Hadron Collider (LHC) - near Geneva, Switzerland. Fujikura will supply 2, 500 km of fibre to collect beam instrumentation data from the LHC. To provide reliable communications, the fibre must be able to withstand localised radiation levels of up to 20 k. Gy/year enough to cause radiation-induced attenuation in normal optical fibre. 4 September 2007 TWEPP 2007 - Prague 22
Conclusions • F-doped SM fibers from Fujikura Ltd show superior performance and have been selected for the LHC : – Production of 3000 km from Nov 06 – Aug 07 completed – Sample tests of series production ongoing • RIA in Co-60 and HEP radiation fields comparable – – radiolysis knock on process particle type particle energy • RIA < 5 d. B/km at 1310 nm and 1550 nm (< 1 MGy) unprecedented result – meets LHC specifications 4 September 2007 TWEPP 2007 - Prague 23
Series sample testing (60 Co) 4 September 2007 TWEPP 2007 - Prague 24
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