Beam Delivery Simulation Development & BDS / MDI Applications

1. Beam Delivery Simulation Development &BDS / MDI Applications L. Nevay, S. Boogert, H. Garcia-Morales, S. Gibson, J. Snuverink, L. Deacon Royal Holloway, University of London 13th May 2014 http://twiki.ph.rhul.ac.uk/twiki/bin/view/PP/JAI/BdSim laurie.nevay@rhul.ac.uk

2. Outline BDSIM structure & overview Previous studies using BDSIM Prospects for Linear Collider Studies High Luminosity LHC studies Current developments On going simulations

3. Beam Delivery SIMulation • Beam Delivery Simulation is a Geant4 based tool for tracking and energy deposition studies in linear colliders • Started by G. Blair at Royal Holloway • Geant4 simulation with fast in-vacuum tracking routines L. Deacon TUPC005 EPAC 08

4. Using Geant4 • Geant4 - a C++ Monte-Carlo framework • Tracking of particles through matter • Access to electromagnetic, hadronic & optical processes • Powerful geometry description framework • Many visualisation tools • No main() function or complete program • Must write your own C++ simulation • BDSIM uses ASCII input files with MAD-like syntax • Builds accelerator beamline as Geant4 model • Utilises its own fast tracking routines for typical magnets • Standalone program – no compilation

5. CLIC Beam Delivery System • BDSIM used to accurately simulate beam losses for CLIC • Losses due to secondaries and showers are important Phys. Rev. S.T. Accel. & Beams 12 081001 2009

6. BDSIM for Linear Colliders • Current developments are towards circular colliders… however… • BDSIM is already suitable for linear colliders! • Current developments improving efficiency and usability • Significantly increased efficiency ~40x faster • Input from MADX and MAD8 improved • Can convert MAD scripts or use twiss output in TFS file • Support for GDML added and being improved

7. Input Sources • Machines are typically designed in some other software • MADX, MAD8 etc • Geometry descriptions in other formats • GDML, LCDD, Mokka • Improvements on easily importing input sources • Can convert MAD scripts directly to GMAD (bdsim) syntax • Or use new python suite to convert input formats • pybdsim– included with BDSIM • TFS files for both MAD8 and MADX accepted • Can programmatically vary input files using python • adjust collimator settings for different runs • adjust magnet strengths

8. LHC and HiLumi LHC • BDSIM being developed for rings • CERN uses SixTrack for tracking studies • applies aperture definition after tracking complete • digital loss maps • custom physics routines for collimator scattering • Use FLUKA for energy deposition near IPs • Aim to use BDSIM for accurate loss maps around ring • Detailed energy deposition due to primaries and secondaries

9. The LHC Model • 27 km Geant4 model • ~1s / particle revolution • Converted from MADX twiss output • Under development • Symplectic tracking routines to be added

10. ATF2 Simulations • Practice lattice for larger linear collider • Conversion of large linear lattice straightforward • Readily applicable to ILC / CLIC • Large lattice conversion from LHC particle impact ATF2 lattice S.T. Boogertet al. WEPC46 IBIC 2013

11. Generic Geometry Library • Currently basic cylinders of material • if not specifying geometry • can detail size and material easily • Library of different magnet types being added • conventional normal conducting 2n-pole magnets • basic LHC quadrupole & dipole • Easily extendable for generic types • Improves the accuracy of particle / radiation transport • ILCcryo-modules already exist as separate geometry

12. The Beam Delivery System • The BDS has many features that require simulation • Diagnostics • Compton systems (laserwires / polarimeters) • laserwires as main emittance measurement during operation • Betatron and energy collimation • IPBSM / tune up station • Dumps • Possible SC magnets • Dosimetry • All require accurate beam loss predictions

13. Laserwire Simulations • Royal Holloway have extensive experience with laserwires • laser used to scan across electron / positron beam for emittance measurement • Compton-scattered photon flux measured • Compton cross-section is low – requires high power laser • GW peak powers • Low number of scattered photons (~1 – 1000) • Requires high precision for accurate emittance measurement • Agapov et al. Phys. Rev. ST Accel. Beams 10, 112801 (2007) • Not a problem at few Hz bunch train frequency • Much better to perform intra-train scanning • Fibre lasers suitable for this and being developed • Up to several MW peak powers demonstrated for intra-train scanning • Laser requirements depend on background levels and location

14. Laserwire Simulations • Simulations underway at Royal Holloway • Determine background levels and location • Develop more definite requirements for laserwire • Affects: • scan precision • laser requirements • choice of laser technology • scanning methodology • detector design & placement L. Deacon TUPC005 EPAC 08

15. Current Development • BDSIM is under active development • 5 active developers • Open source! • Contributions and collaborators welcome • Git repository https://bitbucket.org/stewartboogert/bdsim • Can not only ‘checkout’ latest version but also ‘fork’ and develop yourself • Can then merge into BDSIM

16. Conclusions • BDSIM is a mature beam line simulation tool • Under active development • Being developed for circular colliders • Open source and easily extendable! • Readily useable for linear collider studies

17. Thank you http://twiki.ph.rhul.ac.uk/twiki/bin/view/PP/JAI/BdSim laurie.nevay@rhul.ac.uk