Beta-beam Ion Losses, 1

1
The EURISOL Beta-beam Acceleration Scenario
Ion Losses

• A. Fabich, CERN
• NuFact06, UCIrvine

2
Outline

• EURISOLDS Beta-beam layout
• Accumulation accelerator cycle
• Ion intensities
• Accelerator chain
• Decay distribution
• Dynamic vacuum
• Decay ring
• Stored energy
• Particle turnover

3
Beta-beam EURISOL design
Low-energy part
High-energy part
Ion production
Acceleration
Neutrino source
Beam to experiment
Proton Driver
Acceleration to final energy PS SPS
Ion production ISOL target Ion source
SPS
Decay ring Brmax 1000 Tm B 6 T C 7000 m
Lss 2500 m 6He g 100 18Ne g 100
Neutrino Source Decay Ring
Beam preparation ECR pulsed
Ion acceleration Linac
PS
Acceleration to medium energy RCS
4
Machine cycle

• Baseline version
• Production
• 6He, 18Ne
• ECR, Linac and RCS
• Cycling at 10 Hertz
• Accumulation in the PS
• Accumulation of 20 RCS bunches (2 seconds)
• Acceleration through PS and SPS as fast as
  possible
• gtop 100 for both isotopes
• Injection into decay ring
• Merging with circulating bunches
• Every 6 s for 6He and every 3.6 s for 18Ne

5
Ion intensities (1)

• For the design goal of
• 2.91018 antineutrinos/year
• 1.11018 neutrinos/year
• Required isotope intensities
• For cycling of version EURISOL DS
• Typical intensities of 108-109 ions for LHC
  injector operation (PS and SPS)

6He 18Ne
Decay ring ions stored 9.71013 7.51013
SPS ej ions/cycle 9. 01012 4.31012
PS ej ions/cycle 9.51012 4.31012
Source rate to ECR ions/s 21013 21013
6
Ion intensities (2)
Bunch 20th 15th 10th 5th 1st
total

• Cycle optimized for neutrino rate.
• 30 of first 6He bunch injected are reaching
  decay ring
• Overall only 50 (6He) and 80 (18Ne) reach decay
  ring
• Normalization
• Single bunch intensity to maximum/bunch
• Total intensity to total number accumulated in RCS

7
Decay losses

• Relative decay distribution similar for both
  isotopes
• 90 of all decays before entering decay ring
  occur in the PS
• Can be translated into power losses and compared
  with existing high intensity operation

8
Loss distribution and dyn. vacuum
Pressure evolution due to desorption
PS
PS
1E-8
SPS
SPS
Average pressure mbar
1E-9
1E-9
1E-10
Average pressure mbar
New PS
New PS
1E-11
1E-12
P. Spiller et al., GSI
9
Beam intensities in the decay ring

• Stored energy
• LHC refers to proton operation.
• Transverse density rEstored/(2Pisxsy)
• Beta-beam operates at reasonable stored energy
  and energy density.
• Stored energy is most relevant for irregular
  operation.

10
Particle turnover

• 810 kJ respect. 1150 kJ beam energy/cycle
  injected ? ejected
• All ions have to be removed again
• Either as parent or daughter ion
• Decay deposition in arcs protect SC dipoles from
  quench caused by deposition accumulated after
  drift (quench limit 10W/m)
• Decays accumulated along straight section 300 or
  400 kJ dumped per cycle (50 or 120 kW average)
  via extraction system at end of straight section

3)
1)2)