The superconducting parallel-bar cavity is a deflecting/ crabbing cavity with attractive properties, compared to other conventional designs, that is currently being considered for a number of applications. The new parallel-bar design with curved loading elements and circular or elliptical outer conductors have improved properties compared to the designs with rectangular outer conductors. We present the designs proposed as the deflecting cavities for the Jefferson Lab 12 GeV upgrade and for Project-X and crabbing cavities for the proposed LHC luminosity upgrade and electron-ion collider at Jefferson Lab

De Silva, Subashini

Delayen, Jean R.

English

The superconducting parallel-bar cavity is a deflecting/crabbing cavity with attractive properties, compared to other conventional designs, that is currently being considered for a number of applications. The new parallel-bar design with curved loading elements and circular or elliptical outer conductors have improved properties compared to the designs with rectangular outer conductors. We present the designs proposed as deflecting cavities for the Jefferson Lab 12 GeV upgrade and for Project-X and as crabbing cavities for the proposed LHC luminosity upgrade and electron-ion collider at Jefferson Lab

Delayen, J. R.

De Silva, S. U.

UNT Digital Library

Designs of Superconducting Parallel-Bar Deflecting Cavities for Deflecting/Crabbing Applications

Old Dominion University

printed bywww.postersession.com499 MHz DELFECTING CAVITY2.52.62.72.82.93.03.1300 325 350 375 400EP/ETCavity Length (mm)Angle = 20 deg 40 deg 60 degBar Height = 60 mm 100 mm 140 mm4.04.55.05.56.06.57.07.5300 325 350 375 400BP/ET        (mT/(MV/m))Cavity Length (mm)Angle = 20 deg 40 deg 60 degBar Height = 60 mm 100 mm 140 mm Is required to separate the 11.025 GeV beam into 3 beams Required peak transverse voltage = 5.6 MVDimensional Constraints  Shape of the bar is optimized to achieve a fieldbalancing ratio of BP/EP=1.5 mT/(MV/m)4.04.55.05.56.06.57.07.52.50 2.75 3.00 3.25 3.50BP/ET(mT/(MV/m))EP/ETBar Height50 mm60 mm70 mm80 mm90 mm100 mm110 mm120 mmBp/Ep = 1.5(mT/(MV/m))Final DesignDESIGN OPTIMIZATION AND PROPERTIES FOR EACH APPLICATIONDesign Optimization• Cavity length and bar length is optimized tolower peak surface electric (EP) and magnetic(BP) fields• Shape of the bar is optimized for lower andbalanced surface fields by changing the innerbar height and angle400 MHz CRABBING CAVITY Required peak transversevoltage = 10 MV Shape of the bar is optimized toachieve a field balancing ratio ofBP/EP=1.86 mT/(MV/m)Dimensional Constraints7.07.27.47.67.88.08.28.43.50 3.75 4.00 4.25BP/ET(mT/(MV/m))EP/ETBar Height80 mm90 mm100 mm110 mm120 mmBp/Ep =1.86(mT/(MV/m))Final DesignThe parallel-bar geometry with the cylindrical outer conductor and trapezoidal shaped bars has proven to have improved properties compared to other parallel-bar geometries, therefore have been considered for a number ofdeflecting/crabbing cavity applications. This geometry is capable of delivering lower and well balanced peak surface fields with higher shunt impedance. Another attractive feature is the fact that this geometry has no lower-order modeand the nearest higher-order mode is far removed from the fundamental mode [3]. The shape of the bars connecting to the outer conductor with sloped end plates adds rigidity to the design in terms of mechanical deformations [4].The parallel-bar geometry for the applications of the 499MHz and 365.625 MHz deflecting cavities and 400 MHz crabbing cavities have shown very attractive properties in meeting the requirements.The 499 MHz deflecting and 400 MHz crabbing cavities are in the stage of prototype fabrication [4].CONCLUSIONSisDESIGN OF SUPERCONDUCTING PARALLEL-BAR CAVITIES FOR DEFLECTING/CRABBING APPLICATIONS*J. R. Delayen#1,2 and S. U. De Silva1,21 Center for Accelerator Science, Old Dominion University, Norfolk, VA  23529, U.S.A. 2 Thomas Jefferson National Accelerator Facility, Newport News, VA  23606, U.S.A.[1] J.R. Delayen and H. Wang, Phys. Rev. ST Accel. Beams 12, 062002 (2009).[2] J.R. Delayen and S.U. De Silva, Design of Superconducting Parallel-bar Deflecting/Crabbing Cavities with Improved Properties, Proceedings of PAC’11, New York, (2011). [3] S.U. De Silva and J.R. Delayen, Analysis of HOM Properties of Superconducting Parallel-Bar Deflecting/Crabbing Cavities, These Proceedings.[4] H. Park, J.R. Delayen and S.U. De Silva, Mechanical Study of Superconducting Parallel-Bar Deflecting/Crabbing Cavities, These Proceedings.REFERENCESThe superconducting parallel-bar cavity is a deflecting/crabbingcavity with attractive properties, compared to other conventionaldesigns, that is currently being considered for a number ofapplications. The new parallel-bar design with curved loadingelements and circular or elliptical outer conductors have improvedproperties compared to the designs with rectangular outerconductors. We present the designs proposed as the deflectingcavities for the Jefferson Lab 12 GeV upgrade and for Project-X andcrabbing cavities for the proposed LHC luminosity upgrade andelectron-ion collider at Jefferson Lab.ABSTRACT*Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a non-exclusive, paid-up, irrevocable,world-wide license to publish or reproduce this manuscript for U.S. Governmentpurposes.Part of this work was done in collaboration with and supported by Niowave Inc. under theDOE STTR program.#delayen@jlab.orgParameter 499 MHz 400 MHz 750 MHz 365.6 MHz UnitsFrequency of π mode 499.0 400.0 750.0 365.625 MHzλ/2 of π mode 300.4 375.0 199.9 410.0 mmFrequency of 0 mode 1035.9 729.5 1314.4 659.7 MHzFrequency of near neighbour mode 771.2 593.4 1143.1 571.9 MHzCavity length 440.0 520.0 300.0 530.0 mmCavity diameter 241.9 339.8 193.0 388.4 mmBars length 260.0 345.0 185.0 350.0 mmBars inner height 50.0 80.0 57.5 85.0 mmAngle 50.0 50.0 36.2 55.0 degAperture diameter 40.0 84.0 60.0 84.0 mmDeflecting voltage (VT*) 0.3 0.375 0.2 0.41 MVPeak electric field (EP*) 2.96 3.82 4.95 3.61 MV/mPeak magnetic field (BP*) 4.49 7.09 8.74 6.41 mTBP* / EP* 1.52 1.86 1.77 1.77 mT/(MV/m)Energy content (U*) 0.029 0.19 0.056 0.19 JGeometrical factor 105.6 119.7 136.9 115.9 Ω[R/Q]T 982.2 312.2 152.9 378.5 ΩRTRS 1.04×105 3.7×104 2.1×104 4.4×104 Ω2At ET* = 1 MV/m Change in the transverse voltage across the beam aperture isdetermined in horizontal (along x axis) and vertical (along y axis)directions If needed, the non-linearity can be reduced by increasing the inner barheight and/or by giving it a curvatureANALYSIS OF FIELD NON-LINEARITY1.0001.0051.0101.0151.0201.0251.0301.035-10 -5 0 5 10δVT/VTOffset along x axis (mm)499 MHz 400 MHz 750 MHz 365.6 MHz0.9650.9700.9750.9800.9850.9900.9951.000-10 -5 0 5 10δVT/VTOffset along y axis (mm)499 MHz 400 MHz 750 MHz 365.6 MHz Is required for head on collision  of the 60 GeV proton beam and the 12 GeV electron beam Design is very compact and has higher surface fields750 MHz CRABBING CAVITY Is required to separate the 3 GeV proton beam into 3 beams  Required peak transverse voltage = 10 MV  Shape of the bar is optimized to achieve a field balancing ratio of BP/EP=1.77 mT/(MV/m) 365.625 MHz DEFLECTING CAVITYINTRODUCTIONThe superconducting parallel-bar cavity [1] geometry with a cylindrical outerconductor and trapezoidal shaped bars is proven to have better propertiescompared a variety of geometries with rectangular, cylindrical and elliptical outerconductors and straight, curved bars [2, 3].The geometry has lower and balanced surface fields higher shunt impedance wider mode separation in the HOM spectrumApplications of the Parallel-Bar Cavity 499 MHz deflecting cavity for the Jefferson Lab 12 GeV upgrade 400 MHz crabbing cavity for the proposed LHC luminosity upgrade 750 MHz crabbing cavity for medium energy electron ion collider (MEIC) atJefferson Lab 365.625 MHz deflecting cavity for Project-XField Profile Surface FieldsElectricFieldMagneticFieldSurface Electric FieldSurface Magnetic FieldCAVITY DESIGNS FOR EACH APPLICATION499 MHzDeflecting Cavity400 MHzCrabbing Cavity750 MHzCrabbing Cavity365.625 MHzDeflecting CavityEP/ETBP/ET(mT/(MV/m))EP atVT =3 .4MVBP atVT =3 .4MV3.82 7.09 34.6 MV/m 64.3 mTEP/ETBP/ET(mT/(MV/m))EP atVT =3 MVBP atVT =3MV2.96 4.49 30 MV/m 45 mTEP/ETBP/ET(mT/(MV/m))EP atVT =3 .4MVBP atVT =3.4MV3.61 6.41 30.0 MV/m 53.2 mTR = 20 mm300 mm5th PassBeam Line4th Pass Beam Line450 mm680 mm42 mm 150 mm194 mmB1 B2B2150 mmVTHall CHall BHall AAngleInner bar heightCavity LengthBar Length

Design of Superconducting Parallel Bar Cavities for Deflecting/Crabbing Applications

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Design of Superconducting Parallel Bar Cavities for Deflecting/Crabbing Applications

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