FNAL 8 GeV SC linac / HINS Beam Dynamics
Jean-Paul CarneiroFNAL Accelerator Physics Center
Peter N. Ostroumov, Brahim MustaphaANL
March 13th , 2009
Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13h, 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 MHz 1300 MHz
~1.7 km~8 GeV
Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13h, 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 linac @ 2 MW
■ Work in Progress • New PTRACK (Parallel TRACK) simulations (865 M particles) (PTRACK runs on parallel on BlueGene Supercomputer @ ANL)
• Implementation of diagnostic drifts in the HINS linac lattice
Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13h, 2009
Lattice sections of the FNAL 8 GeV linac
SectionNo.
SectionName
Wout(MeV)
CavitiesNo.
FocusingType
PeriodNo.
Lf(m)
z(m)
1 CH 10 16 S1R 16 0.49- 0.75 17
2 SSR1 32 18 S1R 18 0.75 31.4
3 SSR2 124 33 S2R 18 1.6 61.0
4 TSR 421 42 FRDR 21 3.8 142.2
5 S-ILC 1223 56 F2RD2R 14 6.1 226.7
6 ILC1 2445 63 F4RD3R 9 12.2 336.5
7 ILC2 8000 224 F8RD8R 14 24.2 678.1
Total 8000 452 110 ~678
Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13h, 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.
f
LL
f
TT L
kL
k 00
00 ,
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 13h, 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 13h, 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 13h, 2009
20
2
3
)sin(
)(
1
2 cm
eELsmf
s
n=1 parametric resonance
Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13h, 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 13h, 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 13h, 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 13h, 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 line @ 300 K Transfer line @ 150 K
Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13h, 2009
PTRACK simulations of the FNAL RFQ at 45 mA (BlueGene, ANL)
• 1M
• 10M
• 100M
• 865M32768 processors ~ 5H30
Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13h, 2009
Beam Envelopes Beam 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 13h, 2009
1 W/m limit
MEBT – Option 1: StriplinesWS (+100)
Tor (+100) Tor (+100)
WS (+100)800?
Strip (0) Strip (0)Strip (0)
Strip (0)
200
HINS lattice with drifts (V. Scarpine / 19-FEB-09)
Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13h, 2009
Jean-Paul Carneiro Meeting on HINS Beam Dynamics & Diagnostics, FNAL, March 13h, 2009
Comparison HINS lattice with drifts @ 45 mA / Project X @ 45 mA(Implementation of drifts in HINS lattice = Work in Progress)
Trans. Emittance looks OK Long. 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 13h, 2009
Top Related