FNAL 8 GeV SC linac / HINS Beam Dynamics Jean-Paul Carneiro FNAL Accelerator Physics Center Peter N. Ostroumov, Brahim Mustapha ANL March 13 th, 2009

Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009 HINS / FNAL 8 GeV SC Linacs ▪ FNAL 8 GeV SC linac : 1.56E14 protons per cycle in the MI 10 Hz, 1 msec, 2 MW at 8 GeV ▪ HINS linac ~ 35 m, ~ 60 MeV ~16 m ~10 MeV ~140 m ~420 MeV ~670 m ~8 GeV ~60 m ~120 MeV 325 MHz1300 MHz ~1.7 km ~8 GeV

Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009 Content ■ Lattice design of the FNAL 8 GeV linac Design recipes for high-intensity linacs Design and optimization of the FNAL 8 GeV lattice performed with TRACK by P. Ostroumov at ANL and benchmarked with ASTRA (DESY) by J.-P. Carneiro at FNAL ■ TRACK H-minus stripping simulations (gas, blackbody, EM force) FNAL 8 GeV 2 MW ■ Work in Progress New PTRACK (Parallel TRACK) simulations (865 M particles) (PTRACK runs on parallel on BlueGene ANL) Implementation of diagnostic drifts in the HINS linac lattice

Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009 Lattice sections of the FNAL 8 GeV linac Section No. Section Name Wout (MeV) Cavities No. Focusing Type Period No. Lf (m) z (m) 1CH1016S1R SSR13218S1R SSR212433S2R TSR42142FRDR S-ILC122356F2RD2R ILC F4RD3R ILC F8RD8R Total ~678

Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009 Design Recipes for High-Intensity Linacs (F. Gerigk, Space Charge and Beam Halo in Proton Linacs, 2003) ■ The zero current phase advance of transverse and longitudinal oscillations should be kept below 90° per focusing period to avoid parametrically-excited instabilities at high current ■ The transverse and longitudinal wavenumbers kx0, ky0, kz0 must change adiabatically along the linac. This feature minimizes the potential for mismatches and helps assure a current independent lattice. Phase advance Focusing Period Length ■ Avoid the n=1 parametric resonance between the transverse and longitudinal motion. It can be avoided by proper choice of operational tunes in the Kapchinskiy stability diagram. ■ Avoid strong space charge resonances by selecting stable areas in the Hofmann’s stability chart ■ Provide proper matching in the lattice transitions to avoid appreciable halo formation and emittance increase

Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009 Trans. and Long. Phase Advances (Zero Current) per Focusing Period ■ Transverse and longitudinal oscillations are kept below 90° in most of the focusing periods

Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009 Wavenumber(s) along the linac (Zero Current) ■ kT0, kL0 adiabatic despite of many lattice transitions with different types of focusing and inter-cryostat spaces, cavity TTF.

Kapchinskiy stability diagram (Zero Current) (I. M. Kapchinskiy, Theory of resonance linear accelerators, 1985) O=TRACK x=ASTRA Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009 n=1 parametric resonance

Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009 Trans. & Long. Tune depression along the linac (45 mA) ■ Moderate Trans. & Long. tune depression along the linac Tune depression : Wavenumber with SC Wavenumber without SC

Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009 Hofmann’s Chart for the FNAL 8 GeV linac 45 mA ■ Avoid strong space-charge resonances

Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009 RMS emittance growth along the FNAL 8 GeV linac at 45 mA ■ Main contribution from –MEBT, irregular lattice –Inter-cryostat drift space Beam diagnostics –Lattice transition Increase of focusing length –Long focusing periods in the S-ILC section –Beam matching is good but not perfect ■ Emittance growth is low and acceptable for the HINS PD

Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009 Blackbody H-minus Stripping Simulations with TRACK H  stripping now in the beam dynamics simulation code TRACK (residual gas, black-body radiation, magnetic field) Simulation on Fermi Grid (1E6 × 100 runs = statistics on 1E8 particles) 1 W/m limit Transfer 300 KTransfer 150 K

Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009 PTRACK simulations of the FNAL RFQ at 45 mA (BlueGene, ANL) 1M 10M 100M 865M processors ~ 5H30

Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009 Beam EnvelopesBeam Emittances PTRACK Error simulations of the FNAL 8 GeV linac at 45 mA (100 seeds, 10M each, 4096 processors, 1H30, BlueGene, ANL)

■ RF errors: all misalignments, 1 deg and 1%, rms Beam Losses (W/m) PTRACK Error simulations of the FNAL 8 GeV linac at 45 mA (100 seeds, 10M each, 4096 processors, 1H30, BlueGene, ANL) Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, W/m limit

MEBT – Option 1: Striplines WS (+100) Tor (+100) WS (+100) 800? Strip (0) 200 HINS lattice with drifts (V. Scarpine / 19-FEB-09) Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009

Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009 Comparison HINS lattice with 45 mA / Project 45 mA (Implementation of drifts in HINS lattice = Work in Progress) Trans. Emittance looks OKLong. Emittance needs more tuning

Conclusion ■New concept of pulsed H-minus/proton linac design has been developed –Fully SC above 10 MeV –Cost-effective design of the SC linac can provide acceptable beam quality for peak current ~45 mA ■ H-minus stripping simulations now available with PTRACK ■ Work in progress High-statistics simulations of machine errors (100E6 × 100 = statistics on 1E10) show acceptable <0.1 W/m losses Implementation of drifts in HINS lattice looks OK Optimization of the lattice in high energy section Include realistic LLRF model into parallel TRACK Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13 h, 2009