Design Work for the HESR HighEnergy Storage Ring

1
Design Work for the HESR High-Energy Storage Ring
33rd ICFA Advanced Beam Dynamics Workshop on
"HIGH INTENSITY AND HIGH BRIGHTNESS HADRON
BEAMS, Bensheim, Germany, October 18-22, 2004
A. Lehrach, IKP, Forschungszentrum Jülich

• Introduction
• Experimental Requirements
• Magnet and Lattice Design
• Beam Cooling and Cooler
• Beam Dynamics Issues
• Conclusion

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Facility for Antiproton and Ion Research
HESR

• Antiproton production
• Linac 50MeV H-
• SIS18 51012 protons / cycle
• SIS100 2-2.51013 protons / cycle
• Production target 29 GeV protons
• bunch compressed to 50nsec
• 2107/s (71010/h) antiprotons

3
HESR Reference Design (from Conceptual Design
Report)
HESR consortium consists of FZJ, GSI and TSL
Circumference 443.4 m Beam Rigidity 50
Tm Dipole field 4T
Beam Parameter 0.8 - 14.5 GeV 1.5 - 15
GeV/c Nmax 51011 L 2x1032 cm-2s-1
Ntarget 1015 - 1016 cm-2 Beam Quality 0.001
- 0.1 mm mrad ?p/p 10-4 - 10-5 Beam
Accumulation 2107/s (71010/h)
HESR

• Accelerator RD work
• magnetized e-cooler (8 MV)
• stochastic cooling system
• broadband feedback system
• RF cavities, sc magnets
• impedance budget

4
Experimental Requirements

• PANDA (Strong Interaction Studies with
  Antiprotons)
• Momentum 1.5 to 15 GeV/c
• Number of particles up to 51011
• Maximum luminosity lt 21032 cm-2s-1
• Transverse emittance 0.001 to 0.1 mm mrad
• Momentum spread 110-5 to 110-4
• Interaction point with ß lt 1 m
• Modes operation
• high luminosity mode 2 1032 cm-2sec-1 and
  rms momentum spread s(p) /p 10-4
• high resolution mode 1031 cm-2sec-1 and
  rms momentum spread s(p) /p 10-5
• Experiments with polarized antiproton beams are
  considered!
• Polarized antiproton beam has to be generated in
  a dedicated ring and accelerated
• Different experimental setup with very small
  betatron amplitude and large dynamic aperture

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Injection and Accumulation (by S. Martin,
preliminary )

• Pbar in RESR at 3GeV with a total geometric
  emittance of 1mm mrad and total relative momentum
  spread of 510-4
• 71010 particles per hour are deilvered
• Accelerated in SIS100 to desired energy and
  injected via septum, kicker and barrier bucket
  cavity
• Beam parameter for HESR injection
• 0.85GeV Transverse emittance 0.5mm mrad
  rms geometric, relative momentum spread 7.410-4
  rms
• 14.5GeV Transverse emittance 0.05mm mrad rms
  geometric, relative momentum spread 0.610-4 rms

Septum Parameter
Kicker Parameter
Injection over the whole momentum range of 1.5 lt
p lt 15 GeV/c!!!! Kicker length 7.5 m at 0.04 T
0.6 m3 ferrite!
Barrier Bucket Cavity!
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Magnet Parameter
Recommendation of Accel and the Consortium
members Easiest modification of BNL type dipole
magnets is to reduce the magnet length. All other
parameters (aperture, max. Field, curvature) are
more difficult to modify. Short straight dipoles
are recommended.
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Lattice Parameter (SC versions)
Recommendation of Accel and RHIC magnet group
Distance between magnets of 0.5m very demanding.
In RHIC the distance is about 1.4m, in LHC two
cryostats are 1m apart. A distance of 1m seems
realistic. Total length will increase NC
version will increase to 662m - 692m!
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Proposed Lattice

• 6-fold symmetry, adjustable (negative) momentum
  compaction
• 50Tm magnetic rigidity, 560m circumference
• Dipole magnets sc, 4T, 1.64m straight, 100mm
  coil aperture
• Experiment
• Zero dispersion straights
• Betatron amplitude at the target 1m
• Beam cooling (electron stochastic)
• Betatron amplitude adjustable
• Mixing factor, phase advance pickup and kicker

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Optics of 6-fold Symmetry Lattice(by Y. Senichev)
Arc Magnet Arrangement
? Machine optics, talk by Yu. Senichev
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Electron Cooler
Feasibility study of magnetized electron cooling
for the HESR 9/2003 (Budker Institute,
Novosibirsk, RUS)

• HV section
• electrostatic accelerator
• 0.45 - 8 MV, up to 2 A
• charged by H- beam
• Cooling section
• sc solenoid
• length 30 m
• magnetic field 0.2 - 0.5 T
• straightness 10-5
• beam diameter 6 - 10 mm
• Bending section
• electrostatic up to 21 KV/cm
• bending radius 4 m

HESR Electron Cooler
High voltage (8 MV) tank
12 m
Acceleration column
Charger H- Cyclotron
HESR beam
Cooling section
Solenoid
8 m
30 m
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Electron Cooling and Beam-Target (Betacool code
I. Meshkov et al., Dubna)
Electron Cooling 1 A electron current, 25 mm
beam diameter 30 m cooling section, 0.5 T
magnetic field
Target 1015 atoms/cm2, 8mm diameter
Beam 51010 antiprotons
Emittance / pi mm mrad
Momentum Spread /
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Electron Cooling and Beam-Target (MOCAC code A.
Bolshokov, P. Zenkevich, ITEP Moscow)
Emittance growth and momentum spread target
thickness 51015, electron current 1A, beam
energy 8GeV, particles 51010
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Stochastic Cooling System (by H. Stockhorst et
al., Jülich)
Performance of stochastic cooling Phase advance
pickup kicker odd multiple of p/2 Maximum
sensitivity of pickup and kicker (large
bx,y) Optimum gain for cooling system and low
noise Cooling rate for DC beam 1/t W/(NM) W
bandwidth, N particle number, M mixing factor
?/4 loop coupler structures for pickup (PU) and
kicker (KI) 4-8 GHz, transverse and longitudinal
cooling

Ratio r dB at 6 GHz for different numbers of
pickup loop pairs and particle numbers for for T
14.5 GeV with erms0.16 (0.06) mm mrad
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Stochastic Cooling and Beam-Target (Betacool
code I. Meshkov et al., Dubna, calculated by H.
Stockhorst )
Stochastic Cooling Bandwidth 4 GHz
Target 1014, 1015 atoms/cm2
Beam 1010 1011 antiprotons
15
EU Design-Study (FP6)(Facility for Antiproton
and Ion Research, secondary beams)
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Beam Dynamic Issues

• RF Gymnastics
• injection and accumulation scheme, RF
  requirements
• Space charge
• magnet apertures, collimation, feedback system
• Dynamic aperture
• magnet apertures and field quality, lattice
  design
• Impedance budget / feedback
• RF cavity, kicker / pickups, e-cooler and
  target design, feedback
• Beam-target interaction / beam cooling /
  intra-beam scattering
• beam heating and cooling rates (beam
  equilibrium), particle losses
• Trapped Ions
• UHV design, beam pipe coating, clearing
  electrodes, long. fields

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INTAS Project(Advanced Beam Dynamics for Storage
Rings)

• Contractors GSI Darmstadt , FZ Jülich, TSL
  Uppsala, TU Darmstadt, ITEP Moscow, JINR Dubna,
  Univ. Kiev
• Tasks
• 1.) Study of equilibrium cooled beam
  distributions in presents of intra-beam
  scattering, internal target scattering,
  non-linear space charge
• 2.) Simulation of collective effects in cooled
  beams. Control of collective beam instabilities
  induced by ring impedances and trapped ions
• 3.) Developing a beam dynamics software library
  containing benchmarked modules
• 4.) Benchmarking of models and simulation tools
  with cooler storage rings at low beam energy
  (CELSIUS, COSY, ESR, )

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HESR Accelerator Complex for Polarized Beams
Proposal
HESR Polarimeter
HESR 1.5-15GeV/c
Snake
AP 0.24 1.5GeV/c
30 MeV Linac
Snake
LE Polarimeter
AP Polarimeter
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Conclusion

• Technical Design ready by 2006
• In progress
• Injection and accumulation scheme
• Correction schemes and error studies of the
  lattice, diagnostic concept
• Design of magnets, cryostats and other
  accelerator components
• Design of cooling systems
• Investigation of cooling rates
• Modeling and code benchmarking of collective
  effects including beam-target interaction,
  cooling and RF fields
• Feasibility study of polarized beams
• To be done
• Estimation of impedance budget

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Expected Beam Properties
HESR needs powerful cooling systems high
luminosity mode luminosity 21032cm-2sec-1 and
rms momentum spread s(p) /p 10-4 high
resolution mode luminosity 1031cm-2sec-11 and
rms momentum spread s(p) /p 10-5