Status of BDSIM Simulation L. Nevay, S. Boogert, H. Garcia-Morales, S. Gibson, R. Kwee-Hinzmann, J. Snuverink Royal Holloway, University of London 17 th October 2014 2 Beam Delivery Simulation Beam Delivery Simulation (BDSIM) Geant4 and C++ particle tracking code Developed for linear collider background simulation Combines fast in-vacuum tracking with Geant4 physics Simulates interaction of primaries with accelerator Tracks all secondary particles 3 Previous State of BDSIM BDSIM being adapted for use with rings Namely LHC & HL-LHC Existing LHC Lattice partially converted to BDSIM format Some elements missing / not implemented No turn control -> Geant4 models dont typically have rings Offset between ends of model (~100m x & y) Single turn optics shown L. Nevay et. al, In MOPRO045, Proceedings of IPAC 2014 4 Progress Since Then All elements in LHC lattice implemented With rotation Using collimator database All collimator materials set properly Turn control Dynamic volume tracking user limits Terminate all particles once N turns completed Offset solved Inherent to MADX model of LHC More accurate survey model investigated Over 250 extra items Naming and lengths inconsistent between the two Lattice solved as periodic boundary Offset represents extremely small inaccuracy in model Insignificant compared to misalignments of all components 5 4TeV Model TeV B1 in collision optics used as test machine Generic Geometry 3.5um rad emittance x & y 6 Halo in one dimension, Gaussian in other No cropping at 3 Vertical halo as example here 6 Simulation Details primaries 1000 jobs ~ 1.5 days on 150 node farm ~3 Gb output in root format 20GeV energy cut-off 7 4TeV Model Loss Maps primaries S (m) from IR 1 E (GeV / 10cm) 8 IR 7 Detail S (m) from IR 1 E (GeV / 10cm) 9Comparison R. Bruce et. al, Phys. Rev. ST Accel. Beams 17, (2014) BDSIM S (m) from IR 1 E (GeV / 10cm) 10 As A Function of S Number of Particle Impacts S (m) 11 Models in Preparation Aiming to reproduce 4TeV LHC with higher statistics 4TeV 2012 for B2 as well HL-LHC model In all cases, would like numerical comparison with Collimation Team results Underway with help of Hector & Regina at RHUL 12 Improving The Statistics Profiling shows significant time for Geant4 processes Intersection with next volume Volume searching Only passed to normal BDSIM (G4) BDSIM uses exactly the same tracking routines Wrapped in Geant4 steppers for Geant4 model of accelerator Tracker development implementation in final stages Testing underway Interaction with BDSIM also being tested Expect significant improvement in speed -> statistics Leads to more generic plug and play tracking 15 Geometry Improvement Currently using generic geometry Cylindrically symmetric One material Adding Geant4 geometry for an LHC Dipole & Quad Slightly simplified design Correct materials & therefore cross-sections Also more realistic collimator design Naturally leads to geometry libraries for BDSIM Truly generic Normal conducting Superconducting / LHC Hector G-Morales working on this 16Summary LHC Model fully generated BDSIM developed for use with rings First loss maps from 4TeV LHC produced BDSIM loss maps include primaries and secondaries Close qualitative match between BDSIM simulation & measured losses Other models in preparations Quantitative comparison underway Improvements for increased statistics nearly complete More realistic generic geometries being implemented