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e-RHIC with non-scaling FFAG’s. Dejan Trbojevic. Non-scaling FFAG for eRHIC. Introduction to a concept of non-scaling FFAG Requirements for the eRHIC Arc single ring to accept 2.4-10 GeV electron beams 1.9 GeV Linac Going around detectors Matching the straights to arcs - PowerPoint PPT Presentation
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Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Dejan Trbojevic
e-RHIC with non-scaling FFAG’s
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Non-scaling FFAG for eRHIC
• Introduction to a concept of non-scaling FFAG
• Requirements for the eRHIC
• Arc single ring to accept 2.4-10 GeV electron beams
• 1.9 GeV Linac
• Going around detectors
• Matching the straights to arcs
• Summary and required future work
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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What is the non-scaling FFAG?
• The first one is presently being built in UK: “EMMA”• Orbit offsets are proportional to the dispersion function:
x = Dx p/p• To reduce the orbit offsets to +-6 cm range, for momentum range of p/p ~ +- 60 % the dispersion function Dx has to be of the order of:
Dx ~ 6 cm / 0.6 ~ 10 cm • The size and dependence of the dispersion function is best presented in the normalized space and by the H function:
= Dx /x and = D’x x + x Dx x
with H: H = 2 + 2
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Basic properties of the NS-FFAG
A . Particle orbits B. Lattice
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Muon accelerationConcept introduced 1999 at Montauk meeting –Trbojevic, Courant, Garren) using the light source lattice with small emittance minimized H function
- Extremely strong focusing with small dispersion function. - large energy acceptance.- tunes variation- very small orbit offsets- small magnets
Basic properties of the NS-FFAG
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Recent example of the muon acceleration collaboration with the Muon.inc
Orbits magnified 100 timesFrom 2.5 GeV- 10GeV
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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New Concept: Multipass Linac with racetrack FFAG
Chicane
Chicane
Chicane Chicane
Non-scaling FFAG arc
20 Cavities
20 Cavities
Non-scaling FFAG arc
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Layout of the RHIC tunnel
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Possible locations of the magnets
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Previous solution (PAC07)
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Previous work on the non-scaling FFAG in RHIC tunnel
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Layout of the Arc in RHIC
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Design of the arcs – from the densely populated FODO cells for the 2 - 10 GeV electrons
N=648 cellsL=3.6965 mR1=381.23249 mLBD=1.6 mLQF=1.0 m
For the p/p=[0,-80 %]BBD = + 0.078 TBQF = + 0.199 T
GF= 9.15 T/mGD= - 5.4 T/m
@ electron energy=3.8 GeVBmax=0.078 - 5.4 -0.048)=-0.34 TBmax=0.199 +9.150.069)=-0.43T
r=381.23 m
762.
46 m
Orbits are magnified 1000 times
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Design of the arcs – from the densely populated FODO cells for the energy range of 2.4 -> 10 GeV electrons
Orbits in the arc cell – there are 648 cells in the whole ring
Bd/2 Bd/2Bf
0.8 m0.8 m 1.0 m0.5483 m
3.696228 m
44 mm
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Design of the arcs – from the densely populated
betatron functions vs. momentum
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Design of the arcs – from the densely populated
betatron functions vs. momentum
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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The linac – triplets with cavities
10 GeV2.4 GeV
Qd QdQf QfCavity Cavity
7.393 m
Gf =15.8 T/mGd=-10.4 T/m
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Superconducting linac: Betatron Function dependence on energy
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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New concept of the linac – Tunes per Linac cell
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Matching cell – arc to linac
The matching cell lengthis: L=2 3.696 m = 7.393 m
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Design of the large cells – match to the linac
7.393069 m
0.8 m 1.0 m 0.8 m1.0 m
Orbit offset are identical to the arc orbit offsets
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Design of the arcs – Matching to the linac
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Larger cells to match to linac from arcs
Lp_cell Ln_cellLn_cell Lp_cell
Orbit offsets are zero
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Creating the 4.6 m around the detectors
4.6 meters
4.6 m
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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229 meters
SeparationOf 4.6 meters
The whole ring with two straight sections - linacs
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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229 meters
SeparationOf 4.6 meters
The whole ring with two straight sections - linacs
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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The linac
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Time of flight – Path length dependence on energy
Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008
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Summary:• The non-scaling FFAG concept could be applied for eRHIC within the existing tunnel.
• The non-scaling FFAG arc has been constructed to accept in a single pipe electrons in energy range from 2.4 – 10 GeV with a circular 10 GeV electron orbit, maximum orbit offsets of ~70 mm for the lowest energies, and with the maximum magnetic fields of 0.4 T at the lowest energy. The magnetic field strengths for the 10 GeV electrons are Bmax< 0.2 T.
• A new concept of energy recovery linac with small changes in the betatron functions for the six times in energy range has been presented for the first time.
• Possibilities of bypasses and time of flight adjustments have been explored.
• Matching between the arcs and straight sections for linac needs to be improved.
• A special beam line to send electrons towards the detector need to be designed.
