Muon Collider Ring Magnet Progress
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Transcript of Muon Collider Ring Magnet Progress
SC Magnetsat Fermilab
Muon Collider Ring Magnet Progress
Alexander Zlobin
Technical Division Fermilab
SC Magnetsat Fermilab
MC Lattie Design - Y.Alexahin FNAL, November 11 2009
Muon Collider Parameters 10
s (TeV) 1.5 3
Av. Luminosity / IP (1034/cm2/s) 0.8* 3.4
Max. bending field (T) 9.2** 14
Av. bending field in arcs (T) 7.7 12
Circumference (km) 2.6 4
No. of IPs 2 2
Repetition Rate (Hz) 15 12
Beam-beam parameter / IP 0.087 0.087
* (cm) 1 0.5
Bunch length (cm) 1 0.5
No. bunches / beam 1 1
No. muons/bunch (1012) 2 2
Norm. Trans. Emit. (m) 25 25
Energy spread (%) 0.1 0.1
Norm. long. Emit. (m) 0.07 0.07
Total RF voltage (MV) at 800MHz 60 700
+ in collision / 8GeV proton 0.008 0.007
8 GeV proton beam power (MW) 4.8 4.3
-----------------------------------------------------------------------*) With reduction by beam-beam effect**) Not 10T just by mistake
hC
Pfh
Nnf rep
b
~2
1
4
2
0L
P – average muon beam power (~ )
4
Nr
C – collider circumference (~ if B=const)
– muon lifetime (~ )
* – beta-function at IP
– beam-beam parameter
0.5 1 1.5 2
0.6
0.7
0.8
0.9
h
z /
“Hour-glass factor”
MC Ring Magnet Parameters
All Experimenters’ Meeting, 2/15/2010 2Muon Collider Ring Magnet Progress
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3
MC IR Magnet Parameters
MC Lattie Design - Y.Alexahin FNAL, November 11, 2009
Final Focus Quads 9
Requirements adopted for this design:
full aperture 2A = 10sigma_max + 2cm (Sasha Zlobin wants + 1cm more)
maximum tip field in quads = 10T (G=200T/m for 2A=10cm)
bending field 8T in large-aperture open-midplane magnets, 10T in the arcs
IR quad length < 2m (split in parts if necessary!)
Gradient (T/m) 250 187 -131 -131 -89 82
Quench @ 4.5K 282 209 146 146 (with inner radius 5mm larger)
Quench @ 1.9K 308 228 160 160
Margin @ 4.5K 1.13 1.12 1.12
Margin @ 1.9K 1.23 1.22 1.22
Is the margin sufficient? If not lower beam energy or increase * to allow for smaller aperture
We don’t need 5sigma+ half-aperture, 3sigma+ is enough: can accommodate N=50 m!
No dipole field from 6 to 16.5m, is it worthwhile to create ~2T by displacing the quads?
a (cm)
z (m)
5y
5x
All Experimenters’ Meeting, 2/15/2010 Muon Collider Ring Magnet Progress
MAP Proposal: “Work on collider lattices must go hand-in-hand with
the magnet, superconducting rf, and detector studies”.
“The proper design of this ring is a prerequisite for the success of the whole project”.
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Magnet Design Study Issues
Superconductor choice to provide the required Gnom (Bnom) in MC Ring magnets (Q and D) with the required apertures
Magnet operation temperature and margins Field quality Lorentz forces and stress management Magnet radiation heat load, lifetime,
protection Coil cooling and heat removal Magnet quench protection (magnet
inductances and stored energy) etc.
All Experimenters’ Meeting, 2/15/2010 4Muon Collider Ring Magnet Progress
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Baseline conductor – Nb3Sno Best combination of properties (Jc, Tc, Bc2, stress sensitivity)o Commercially available strands in long lengtho Good progress in Nb3Sn accelerator magnet technologies
Superconductor Choice
All Experimenters’ Meeting, 2/15/2010 5Muon Collider Ring Magnet Progress
From P. Lee
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Practical 2-layer designs, Bnom~11-12 T, Bmax~13-14 T Operation margin ~10% @ 4.5K (~20% @ 1.9K)
o Operation at 4.5K more preferable o 10% is OK for Nb3Sn magnets based on LARP studies
Good field quality aperture (<1 unit) ~2/3 coil ID Quench protection looks OK (short magnets) Max stress in Q2, Q3 >150 MPa => Nb3Sn conductor
degradation (OK based on recent LARP results) Nb3Sn IR quads with aperture 90-120 mm are modeled by LARP
Large-aperture IR Quadrupoles
All Experimenters’ Meeting, 2/15/2010 6Muon Collider Ring Magnet Progress
SC Magnetsat Fermilab Traditional 2-layer design
o Bmax(4.5/1.9 K) ~12.5/13.5 T o Margin ~55% @4.5K (~70% @1.9K)o Good field quality inside R<55 mmo Coil shielding in the midplane
shorter magnet, inner absorber, low-Z material in coil midplane,
Open midplaneo New design concepto Bmax(4.5/1.9 K)~9/10 T o Margin ~10% @4.5K (~20%@1.9K) o Field quality is limited
Large stored energy => factor of 5-8 larger than in present LHC IRQ
Design studies: margin, field quality, stress management, quench protection.
Modeling: can we make such magnets!?
8T IR Dipole
All Experimenters’ Meeting, 2/15/2010 7Muon Collider Ring Magnet Progress
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Radiation studies have been started (V. Alexakhin, N. Mokhov)
3 designs with masks: Standard optics, 5-sigma internal absorbers, shifted Q
Muons and Neutrons, Gamma and Electrons
Power distribution, heat load, radiation dose, etc.
Preliminary results are quite encouraging
Issues: o high heat load in masks, o sagitta in 6m long dipole
Study will continue
First Radiation Studies
All Experimenters’ Meeting, 2/15/2010 8Muon Collider Ring Magnet Progress
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High heat deposition (0.5-1kW/m) in magnet midplane => large power consumption => open midplane magnet design
Coil design options: shell-type vs. block-type Coil support => mechanical stricture Coil cooling => indirect cooling scheme is needed
10T Ring Dipole
All Experimenters’ Meeting, 2/15/2010 9Muon Collider Ring Magnet Progress
Aperture – 60mmBop~10T with ~10% margin at 4.5K.
Midplane gap: ~10 mm
New challenging design => model magnet R&D.FNAL plans (HFM program):•FY10 : coil, structure, tooling design and procurement•Practice coil, inner coil fabrication and test•FY11: outer coil fabrication, 1st model test •FY11-13: design and performance optimization
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Conclusions
The level of efforts on MC ring and IR studies (including magnets) has been significantly increased
Collaboration of accelerator, magnet and detector groups has been established
Significant progress has been made in 2009: MC lattice and IR optics, magnets, radiation studies, dynamic aperture… The work will continue.
Present MC Ring magnet parameters are at the limits of Nb3Sn technology
To achieve these parameters magnet design studies and experimental R&D program are neededo Large aperture quadrupole - input from LARPo Collider and IR Dipoles – to be demonstrated!
All Experimenters’ Meeting, 2/15/2010 10Muon Collider Ring Magnet Progress