COMPASS All-Hands Meeting, FNAL, Sept , 2007 Accelerator Prototyping Through Multi-physics Analysis Volkan Akcelik, Lie-Quan Lee, Ernesto Prudencio, Cho Ng, Zenghai Li, Kwok Ko Advanced Computations Department Stanford Linear Accelerator Center Work supported by DOE ASCR, BES & HEP Divisions under contract DE-AC02-76SF00515

2 Multi-physics Analysis for Accelerator Components  Virtual prototyping through computing  Thermal and mechanical analysis as important as EM analysis EM heating, Thermal radiation, Lorentz force detuning, Mechanical stress  Augmented by additional physics particle effects including emittance and multipacting Nonlinear and transit effects in superconducting cavity design  Accurate and reliable multi-physics simulation requires large-scale parallel computing: TEM3P

3 TEM3P: Multi-Physics Analysis CAD Model EM Analysis Thermal Analysis Mechanical Analysis  Finite element based with higher-order basis functions Natural choice: FEM originated from structural analysis!  Use the same software infrastructure as Omega3P Reuse solvers framework Mesh data structures and format  Parallel

4 TEM3P for LCLS RF Gun EM Domain Thermal/Mechanical Domain Benchmark TEM3P against ANSYS CAD Model (courtesy of Eric Jongewaard)

5 RF Gun EM analysis The second mode is operating mode Its magnetic field on the cavity inner surface generates heating! 1 st mode GHz 2 nd mode GHz

6 Mesh for Thermal/Mechanical analysis Mesh: 0.6 million nodes. Materials: Copper + Stainless steel Thermal analysis: 7 cooling channels EM Heating

7 Parameters for Thermal Analysis  TEM3P: cooling channels modelled as Robin BC  7 cooling channels specific temperatures and film coefficients  Thermal load from EM power loss (4000 Watt) EM Heating BC  Thermal conductivity for copper 391  Thermal conductivity for stainless steel 16.2  Other surfaces modelled as homogeneous Neumann BC

8 Thermal Analysis loaded with EM Heating ANSYS TEM3P Maximal Temperature C Maximal Temperature C Temperature Distribution

9 Mechanical Analysis with Thermal Load ANSYSTEM3P Maximal displacement:  mMaximal displacement:  m  Future work: compute stress and shifted frequency due to geometry change

10 Multi-physics Analysis for SRF Cavities and Cryomodules  Thermal behaviors near superconducting region are highly nonlinear  SRF Cavity wall is very thin Anisotropic high-order mesh will reduce significant amount of computing Working with RPI/ITAPS