1 status of emma shinji machida cclrc/ral/astec 23 april, 2006 machida/doc/nufact/...
TRANSCRIPT
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Status of EMMA
Shinji Machida
CCLRC/RAL/ASTeC
23 April, 2006
http://hadron.kek.jp/~machida/doc/nufact/
ffag/machida_20060423.ppt & pdf
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Background
• Electron model of non scaling FFAG was proposed. It is a scaled down model of muon from 10 to 20 GeV ring.
• Beam dynamics aspects are discussed in a regular phone meeting, every two weeks.
• Engineering design recently started at Daresbury Laboratory.
• First iteration of cost estimate has been done.• Proposal is submitted to BT.
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Goals and specifications
Gutter acceleration
Resonance crossing
Large acceptance
Commissioning procedure
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Goal (gutter acceleration)
• Study items– Dependence of “a” and “b” parameters.
– Time of flight variation.– Effects of errors in voltage and phase.– Effects of injection mismatch in longitudinal phase.
• Requirements for hardware– RF frequency: f/f = 10-3 ?– RF voltage: factor of 4 or 6 ?– Precision of RF phase:– Independent knobs for dipole and quadrupole components
€
a =qV
ω ⋅ΔT ⋅ΔE
€
b =T0
ΔTEnergy gainper phase slip
RF frequency relativeto revolution f
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RF frequency range
Calculation by Berg shows we need Df/f = 6 x 10-3
for some operating point.
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RF voltage range
• “a” parameter is proportional to RF voltage and inversely proportional to T.
• If T increases by factor 3 for some operating point, RF voltage increase by the same factor to obtain the same “a”.€
a =qV
ω ⋅ΔT ⋅ΔE
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Phase precision
20x10-3
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1.00.80.60.40.20.0RF phase/2Pi
slope=1.0
• One RF cycle is 770 ps.• Precision of 1 degree means 2 ps.
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Independent knobs for D and Q
• There was a proposal at Fermilab to combine permanent magnet and coils.
• Daresbury people assume a full and a half quadrupole in a movable table.
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Goal (resonance crossing)
• Study items– Tune – Different source of resonance lines.– Crossing rate.– Effects of known misalignments and field errors.– Effects of mismatch at injection.
• Requirements for hardware– Variable gradient: 25% ?– Precision of alignments: 100 m ?– Gradient error: 10-3 ?– RF voltage: factor of 4 ?
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Gradient range
To explore tune space, gradient has a variation of 25%.
Calculation by Berg
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y and y vs. g (scaling parameter of the order of gap)
g [m] g [m]
vert
ical
tune
Ver
tica
l bet
a fu
ncti
on [
m]
Beam size increases 10-15% when g=20-30 mm.
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Alignment errors
• QD– Dipole field: 0.13 T– Quadrupole field: 4.6 T/m– 0.0001 m displacement is 0.46 x 10-3 T or 3.5 x 10-3 of dipole
• QF– Dipole field: 0.051 T– Quadrupole field: 7.4 T/m– 0.0001 m displacement is 0.74 x 10-3 T or 1.5 x 10-2 of dipole
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RF voltage
• If it is high enough to demonstrate “fast crossing”?
• How low can we reduce voltage to simulate “slow crossing” with stable operation?
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Injection mismatch
• Design of injection line to control injection matching.
• How many knobs: quadrupole and steering?
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Goal (large acceptance)
• Study items– Aperture survey at fixed energy.– Acceleration of large transverse amplitude.
• Requirements for hardware– Enough aperture: Main magnet does not have
problem.
RF cavity may have.– RF voltage: factor of 2 ?– Second or third harmonic RF ?– Scanning magnet
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Magnet aperture
Calculation by Berg shows the aperture range of+-20 mm at QD and +-30 mm at QF.
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RF cavity aperture
Rsh
0.0000E+00
2.0000E+05
4.0000E+05
6.0000E+05
8.0000E+05
1.0000E+06
1.2000E+06
1.4000E+06
1.6000E+06
1.8000E+06
2.0000E+06
20 25 30 35 40 45
Rsh
• Cost estimate is based on 25 mm diameter.• We prefer the aperture more than 45 mm.
Calculation by C.D.Beard
Shunt impedance decrease by 33%.
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RF voltage range (10-20GeV muon ring)
E=0 pi, V=1Dp/p=0.36%
E=30 pi, V=1Dp/p=2.8%
E=30 pi, V=1.4Dp/p=0.88%
V/V_nominal
Dp/
p_rm
s
1 2
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higher harmonics (10-20GeV muon ring)
E=0 pi, h=1Dp/p=0.36%
E=0 pi, h=1+2Dp/p=0.42%
E=30 pi, h=1+2Dp/p=0.58%
E=30 pi, h=1+3Dp/p=0.77%
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Goal (commissioning)
• Study items– Time of flight measurement.
• Requirements for hardware
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Commissioning
• Only an injection momentum beam is available when we start commissioning of muon ring.
– Parabola curve without high momentum beam.– “b” parameter without high momentum beam.– How we measure ToF with a single turn?
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Missing items
• Injection and extraction– Optics– Kickers
• Diagnostics – Circulating beam– Extracted beam
• Alternative (low) frequency RF requirement and design.
• and others
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Hardware status
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Magnets
• Gradient is -4.6 T/m for D and 7.4 T/m for F.• Half a yoke for D and full quadrupole for F.• Dipole component is controlled by magnet position.
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RF cavity
• Frequency is 1.3 GHz.• Tuning stubs and RF coupler.• Aperture (diameter) is 25 mm.
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A few cells in a stand
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Layout at Daresbury Laboratory
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Cost estimate• RF cavity system (only for fundamental)
– RF cavity 286,000 (pounds)– Waveguide distribution 331,500– RF amplifier 960,000– Cabling 24,000– HV supply transformer 8,000
• Diagnostics 154,000
• Magnets– Main magnets 466,430– Injection&extraction kicker 40,000
• Mechanical&vacuum chamber 290,400
• Vacuum equipment 134,300
• Controls 121,662
• Electrical (power supply) 298,950
• Cooling&services 70,000
• Civil 42,000
Total 3,227,242 + 1,330,000 (staff)= 4,557,242 (8.1 M$, 9.5 OkuYen, 6.6 Euro)
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Summary
• Physics discussion continues.• Continuous update of parameters and its range.
– We need more details discussions: what parameter region we want to study.
– Iteration between physics requirements and engineering design.
• More precise figure of cost.
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Crossing of x-2y=0
Coupling is visible just before the final energy(red: horizontal (0 p mm), blue: vertical (3 mm)).