ABSTRACT

1. 5 30 BETA_X&Y[m] DISP_X&Y[m] 1 20 BETA_X&Y[m] DISP_X&Y[m] 0 0 0 BETA_X BETA_Y DISP_X DISP_Y 389.302 -1 0 0 BETA_X BETA_Y DISP_X DISP_Y 30.5 [ SIMULATIONS OF A MUON LINAC IN THE INTERNATIONAL DESIGN STUDY FOR THE NEUTRINO FACTORY ** K.B. Beard1#, S.A. Bogacz2, V.S. Morozov2, Y.R. Roblin2 1Muons Inc, 2Jefferson Lab ~ oncrest Pz[MeV/c] bx = 13.0 m by = 14.4 m ax=-1.2ay=1.5 Pre-linac 1 m 244 MeV 900 MeV bx = 7.9 m by = 8.7 m ax=-0.8ay=1.3 Arc 2 Arc 3 Arc 4 1.75 m Arc 1 202 m bx,y → bx,y axy → - axy bx = 3.2 m by = 6.0 m ax=-1.1ay=1.5 bx,y → bx,y axy → -axy Muons, Inc. ~ 1 synch period bx,y → bx,y axy → - axy bx,y → bx,y axy → - axy RLA I 3.6 GeV 0.9 GeV Double achromat Optics 86 m 0.6 GeV/pass RLA II 3.6 GeV 12.6 GeV 146 m t[nS] 255 m 2 GeV/pass quad grad. ABSTRACT The International Design Study for the Neutrino Factory (IDS-NF) baseline design1 involves a complex chain of accelerators including a single-pass linac, two recirculatinglinacs (RLA) and a fixed field alternating gradient accelerator (FFAG). As part of the study, our group simulated the muon acceleration from 0.2 to 12.6 GeV. The first linac follows the capture and bunching section and accelerates the muon of both signs from about 244 to 900 MeV2,3. It must accept a high emittance beam about 30 cm wide with a 10% energy spread.4 This linac uses counterwound, shielded superconducting solenoids and 201 MHz superconducting cavities Next is a 2½ pass 0.6 GeV/pass RLA which takes the beam from 0.9 to 3.6 GeV. It is injected at the middle of the linacand has 2 teardrop-shaped arcs at each end, and is extracted at the end of the linac. Muons of opposite sign travel in the same direction through the linac and in opposite directions around the arcs. The beta-beating technique is used to match the linac to all the arcs; no pulsed nor ramped magnets are needed. It is followed by very similar, but larger 2½ pass 2 GeV/pass RLA that takes the beam from 3.6 to 12.6 GeV. Simulations have been carried out on various sections using several codes including Zgoubi, OptiM5, GPT6, Elegant7 and G4beamline8, first to determine the optics and will later be used to estimate the radiation loads on the elements due to beam loss and muon decay. 3.0 GeV 0.9 GeV 1.2 GeV 1.8 GeV 2.4 GeV 3.6 GeV -V V V -V H H -H -H Linac position 2 cells 4 cells A bunch at the end of the linac with and without induced synchrotron motion. Quad strength as a function of position withiin the RLA linac. G4beamline andOptiMmodels of linac-to-1st RLA achromatic chicane. Longitudinal dynamics remains a challenge for this very large energy spread beam. Beta-beating technique in 1st RLA (linac only – arcs not shown) CONCLUSIONS AND FUTURE PLANS Generally, the GPT, OptiM, elegant, and G4beamline (with some RF phase adjustments) simulations are in good agreement. G4beamline 2.10 includes improvements (“rfdevice”) to better phase the linac. Longitudinal dynamics are still a challenge in the linac, but are ameliorated by running far off-crest. The RLAs have been simulated in OptiM and Elegant, but not yet in G4beamline. Much work remains to be done, especially on G4beamline simulations of the RLAs and chicanes. References Acknowledgements *Supported in part by US DOE STTR Grant DE-FG02-08ER86351 #beard@muonsinc.com [1] Interim Design Report, IDS-NF 020, http://www.ids-nf.org [2] C. Bontoiu et al., IPAC'10, Kyoto, Japan, 23-28 May 2010, pp 4590-4592. [3] J. S. Berg et al., Phys. Rev. ST Accel. Beams, 9:011001,2006. [4] S.A. Bogacz. Nucl. Phys. B Proc. Suppl., 149:309–312, 2005 [5] V. Lebedev, OptiM - http://wwwbdnew.fnal.gov/pbar/organizationalchart/lebedev/OptiM/optim.htm [6] B. van der Geer and M. J. de Loos. General Particle Tracer - http://www.pulsar.nl/gpt/. [7] M. Borland, Elegant - http://www.aps.anl.gov/Accelerator_Systems_Division/Operations_Analysis/oagPackages.shtml. [8] T.J.Roberts, G4beamline - http://g4beamline.muonsinc.com [9] J. Pozimski et al., IPAC'10, Kyoto, Japan, 23-28 May 2010, pp 3479-3481