NLC Beam Delivery Area Engineering: Vacuum System Cost Model Presentation by Leif Eriksson, 02/09/99

02/09/99Leif Eriksson, Area Engineer2 NLC Beam Delivery, Vacuum: General zThe NLC Beam Delivery systems begins where the NLC Linac ends. zIt consists of: yCollimation section yBeam Delivery 1 and 2: xIP Switch xBig Bend: e+ e- xFinal Focus e+ e- yIR 1 and 2

02/09/99Leif Eriksson, Area Engineer3 NLC Beam Delivery, Vacuum: Tunnel Layout zA straw man figure of tunnel access:

02/09/99Leif Eriksson, Area Engineer4 NLC Beam Delivery, Vacuum: Baseline specs zMust have: yBase Pressure 5E-8 Torr yLow electrical resistance ySmall aperture, ~ 1/2” OD yUniform inner diameter, tapered z Specials: yBig Bend, absorb synchrotron radiation

02/09/99Leif Eriksson, Area Engineer5 NLC Beam Delivery Vacuum: Materials zMaterials to chose from: yStainless steel, low outgassing, cheap yAluminum, low outgassing, cheap, good conductor, easy to extrude yCopper, low outgassing, good heat absorber, good conductor, easy to extrude

02/09/99Leif Eriksson, Area Engineer6 NLC Beam Delivery, Vacuum: Comparison z Stainless steel is less favored choice because of high electrical resistance z It’s a toss up between aluminum and copper

02/09/99Leif Eriksson, Area Engineer7 NLC Beam Delivery, Vacuum: The numbers

02/09/99Leif Eriksson, Area Engineer8 NLC Beam Delivery, Vacuum: Conclusion zWith an aluminum chamber the pump spacing is 1-3 m zWith a copper chamber the pump spacing is m zBig Bend may need an anti-chamber to absorb synchrotron radiation z Copper is the preferred material from an engineering stand point: yless component-better reliability yLow outgassing yGood thermal properties yLends itself well for extrusion and brazing yEasy to machine

02/09/99Leif Eriksson, Area Engineer9 NLC Beam Delivery, Vacuum: Components - 1 zNLC Beam Delivery vacuum specification for the purpose of cost estimation and WBS zGENERAL yThe NLC Beam Delivery vacuum system is an Ultra High Vacuum system. All components in direct contact with the NLC Beam Delivery vacuum system must comply with “Technical Specifications for Vacuum Systems”, SLAC-TN zBASE PRESSURE y- The highest pressure in the NLC Beam Delivery System must not exceed 5E-8 Torr. zPUMPS y- The NLC Beam Delivery vacuum system is ion pumped, the pump size is 30 l/s. y- The ion pumps are of VARIAN type with a removable, gold plated high voltage feed through.

02/09/99Leif Eriksson, Area Engineer10 NLC Beam Delivery, Vacuum: Components - 2 zPUMPS, cont. y- The pumps should have remote high voltage power supplies accessible during operation. y- The high voltage ion pump power supplies should display error codes into a central control system. y- The spacing of the ion pumps is one ion pump every 10m or 15m depending on beam line aperture. y- The ion pumps are located immediately adjacent and perpendicular to the beam line y- The ion pumps are connected to the beam line through a flange connection. y- Each ion pump has its own mechanical support. zBEAM LINE y- The preferred material for the beam line is copper due to its low out gassing rate, its low electrical resistance and its good thermal properties. y- Flange connections are made by ConFlat type vacuum flanges. y- All vacuum seals in areas in direct contact with the beam must be all-metal. y- Flange connections will be used in component dense areas. y- Where the component density is low the beam line sections will be welded/brazed together in situ.

02/09/99Leif Eriksson, Area Engineer11 NLC Beam Delivery, Vacuum: Components - 3 zGAUGES y- One gauge assembly measuring total pressure from atmospheric pressure to 2E-10 Torr, every 250m. The gauges must be radiation hardened. y- All functions of the gauge(s) should be able to operate remotely. y- Every beam line section must have a gauge combination, as described above, on both sides of a beam line isolation valve. zRGA y- Every 250m section should contain two Residual Gas Analyzers of radiation hardened type. y- All functions of the RGA should be able to operate remotely. zVALVES y- The beam line isolation valves are all-metal valves of VAT type, radiation hardened. y- The bore is no larger than 1.50”. y- The actuator should be mounted on an extender.

02/09/99Leif Eriksson, Area Engineer12 NLC Beam Delivery, Vacuum: Components - 4 zVALVES, cont. y- The valves must have mechanical indicators displaying OPEN and CLOSED. y- The valve must have micro switches indication OPEN and CLOSED. y- The valves must be operated by a remote solenoid package, J-box, of SLAC type. y- The valves should have local controls every 500m. y- The valves are located 250 m apart. y- All metal right angle valves, 2 3 /4“ CFF should be provided every 50m. zTUNNEL ACCESS y- Access to the tunnel will be provided every 500m. y- A power supply/Control vault will be provided adjacent to the tunnel access, on the ground level. No cable length from a beam line vacuum device to the power supply/ controls vault should have to be longer than 300m. zVACUUM CONTROL ROOM z- The NLC Beam Delivery System should have a centrally located vacuum control room.

02/09/99Leif Eriksson, Area Engineer13 NLC Beam Delivery, Vacuum: Components - 5 zSUMMARY yBased on the above assumptions the NLC Beam Delivery Vacuum System contains the following components, (one side, two IP’s): x30 l/s ion pumps629EA xVacuum gauges33EA xRGA’s33EA xIsolation valves31EA xRight angle valves152EA xBeam line length5305m

02/09/99Leif Eriksson, Area Engineer14 NLC Beam Delivery, Vacuum: Reference text zAll of the presented material is available for downloading from: yhttp://www-sldnt.slac.stanford.edu/nlc/beamdeliveryhome.htm xSee under: Issues\Engineering yA beam line schematic is also available at this location