scenarios for the slhc and the vlhc walter scandale, frank zimmermann cern hcp2007 we acknowledge...
TRANSCRIPT
Scenarios for the sLHC and the vLHC
Walter Scandale, Frank Zimmermann
CERN
HCP2007We acknowledge the support of the European Community-Research Infrastructure Activity under the FP6 "Structuring the European Research Area" programme (CARE, contract number RII3-CT-2003-506395)
outline• LHC upgrade: why and when ?• beam parameters• the two selected scenarios for luminosity upgrade– features, – Bunch structure– IR layout, – merits and challenges
• luminosity leveling ?• summary & recommendations for the sLHC
• perspective for higher energy hadron collisions– VLHC at FNAL – dLHC and tLHC at CERN– R&D– possible plans
0
10
20
30
40
50
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70
0 2 4 6 8 10
years
nb-1
IR quadrupole lifetime ≥ 8 years owing to high radiation doses
halving time of the statistical error ≥ 5 y already after 4-5 y of operation
luminosity upgrade to be planned by the middle of next decade
LHC luminosity upgrade: why and when?
How fast performance is expected to increase:
4 y up to nominal L 4 y up to nominal L & 2 y up to ultimate L
4 y up to ultimate
0
2
4
6
8
10
12
14
16
0 2 4 6 8 10 12 14 16
years
years to halving the statistical error0
200
400
600
800
1000
1200
1400
1600
integrated luminosity [fb-1]
LHC luminosity upgrade: the LARP perspective
Courtesy of V. Shiltsev - FNAL
Name Event DateName Event Date55
W. Scandale/F. Zimmermann, 13.02.2007
parameterparameter symbolsymbol nominalnominal ultimateultimate 12.5 ns, short
transverse emittancetransverse emittance [[m]m] 3.753.75 3.753.75 3.75
protons per bunchprotons per bunch NNbb [10 [101111]] 1.151.15 1.71.7 1.7
bunch spacingbunch spacing t [ns]t [ns] 2525 2525 12.5
beam currentbeam current I [A]I [A] 0.580.58 0.860.86 1.72
longitudinal profilelongitudinal profile GaussGauss GaussGauss Gauss
rms bunch lengthrms bunch length zz [cm] [cm] 7.557.55 7.557.55 3.78
beta* at IP1&5beta* at IP1&5 [m][m] 0.550.55 0.50.5 0.25
full crossing anglefull crossing angle c c [[rad]rad] 285285 315315 445
Piwinski parameterPiwinski parameter cczz/(2*/(2*xx*)*) 0.640.64 0.750.75 0.75
peak luminositypeak luminosity LL [10 [103434 cm cm-2-2ss-1-1]] 11 2.32.3 9.2
peak events per crossingpeak events per crossing 1919 4444 88
initial lumi lifetimeinitial lumi lifetime LL [h] [h] 2222 1414 7.2
effective luminosity effective luminosity (T(Tturnaroundturnaround=10 h)=10 h)
LLeff eff [10[103434 cm cm-2-2ss-1-1]] 0.460.46 0.910.91 2.7
TTrun,optrun,opt [h] [h] 21.221.2 17.017.0 12.0
effective luminosity effective luminosity (T(Tturnaroundturnaround=5 h)=5 h)
LLeff eff [10[103434 cm cm-2-2ss-1-1]] 0.560.56 1.151.15 3.6
TTrun,optrun,opt [h] [h] 15.015.0 12.012.0 8.5
e-c heat SEY=1.4(1.3)e-c heat SEY=1.4(1.3) P [W/m]P [W/m] 1.07 (0.44)1.07 (0.44) 1.04 (0.59)1.04 (0.59) 13.34 (7.85)
SR heat load 4.6-20 KSR heat load 4.6-20 K PPSRSR [W/m] [W/m] 0.170.17 0.250.25 0.5
image current heat image current heat PPICIC [W/m] [W/m] 0.150.15 0.330.33 1.87
gas-s. 100 h (10 h) gas-s. 100 h (10 h) bb PPgasgas [W/m] [W/m] 0.04 (0.38)0.04 (0.38) 0.06 (0.56)0.06 (0.56) 0.113 (1.13)
extent luminous regionextent luminous region l [cm] 4.54.5 4.34.3 2.1
commentcommentpartial wire
c.
(heat load induced by Sync.Rad + image current larger than the local heat load capacity)
baselineupgradeparameters2001-2005
abandonedatLUMI’06
total heat 15.6 W/m >> 2.4 W/m
Name Event DateName Event Date66
W. Scandale/F. Zimmermann, 13.02.2007
parameterparameter symbolsymbol 25 ns, small * 50 ns, long
transverse emittancetransverse emittance [[m]m] 3.75 3.75
protons per bunchprotons per bunch NNbb [10 [101111]] 1.7 4.9
bunch spacingbunch spacing t [ns]t [ns] 25 50
beam currentbeam current I [A]I [A] 0.86 1.22
longitudinal profilelongitudinal profile Gauss Flat
rms bunch lengthrms bunch length zz [cm] [cm] 7.55 11.8
beta* at IP1&5beta* at IP1&5 [m][m] 0.08 0.25
full crossing anglefull crossing angle c c [[rad]rad] 0 381
Piwinski parameterPiwinski parameter cczz/(2*/(2*xx*)*) 0 2.0
hourglass reduction hourglass reduction 0.86 0.99
peak luminositypeak luminosity LL [10 [103434 cm cm-2-2ss-1-1]] 15.5 10.7
peak events per crossingpeak events per crossing 294 403
initial lumi lifetimeinitial lumi lifetime LL [h] [h] 2.2 4.5
effective luminosity effective luminosity (T(Tturnaroundturnaround=10 h)=10 h)
LLeff eff [10[103434 cm cm-2-2ss-1-1]] 2.4 2.5
TTrun,optrun,opt [h] [h] 6.6 9.5
effective luminosity effective luminosity (T(Tturnaroundturnaround=5 h)=5 h)
LLeff eff [10[103434 cm cm-2-2ss-1-1]] 3.6 3.5
TTrun,optrun,opt [h] [h] 4.6 6.7
e-c heat SEY=1.4(1.3)e-c heat SEY=1.4(1.3) P [W/m]P [W/m] 1.04 (0.59) 0.36 (0.1)
SR heat load 4.6-20 KSR heat load 4.6-20 K PPSRSR [W/m] [W/m] 0.25 0.36
image current heat image current heat PPICIC [W/m] [W/m] 0.33 0.78
gas-s. 100 h (10 h) gas-s. 100 h (10 h) bb PPgasgas [W/m] [W/m] 0.06 (0.56) 0.09 (0.9)
extent luminous regionextent luminous region l [cm] 3.7 5.3
commentcomment D0 + crab (+ Q0) wire comp.
New upgradescenarios
compromisesbetween# of pile up events and heat load
injector upgrade
Crossing with large Piwinski angle
aggressive triplet
challenges
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannW. Scandale/F. Zimmermann, 19.03.2007
for operation at beam-beam limitwith alternating planes of crossing at two IPs, luminosity equation can be written as
25 ns 50 ns 50 ns
50 ns
where Qbb = total beam-beam tune shift
(the change of Fh-g due to hourglass effect is neglected above)
Luminosity at the beam-beam limit
€
L ≈ πγ nb
γε( ) frev
rp2β *
ΔQbb2 1+ Θ2 FprofileFh − g
Name Event DateName Event Date88
W. Scandale/F. Zimmermann, 13.02.2007
luminosity reduction factor from
crossing angle
R 0.85 (nominal LHC)
x
zcR
2 ;
1
12
≡ΘΘ+
=
Piwinski angle
Name Event DateName Event Date99
W. Scandale/F. Zimmermann, 13.02.2007
25-ns ultra-low-25-ns ultra-low- upgrade upgrade scenarioscenario stay with ultimate LHC beam stay with ultimate LHC beam
(1.7x10(1.7x101111 protons/bunch, 25 protons/bunch, 25 spacing)spacing)
squeeze squeeze * below ~10 cm in ATLAS & * below ~10 cm in ATLAS & CMS CMS
add early-separation dipoles in add early-separation dipoles in detectors, one at ~ 3 m, the other detectors, one at ~ 3 m, the other at ~ 8 m from IPat ~ 8 m from IP
possibly also add quadrupole-possibly also add quadrupole-doublet inside detector at ~13 m doublet inside detector at ~13 m from IP from IP
and add crab cavities (and add crab cavities (ffPiwinskiPiwinski~ 0), ~ 0), and/or shorten bunches with and/or shorten bunches with massive addt’l RFmassive addt’l RF
new hardware inside ATLAS & CMS, new hardware inside ATLAS & CMS,
first hadron-beam crab cavities first hadron-beam crab cavities
(J.-P. Koutchouk et al)
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannW. Scandale/F. Zimmermann, 19.03.2007
CMS & ATLAS IR layout for 25-ns option
ultimate bunch intensity & near head-on collision (RΘ1)
stronger triplet magnetsD0 dipole
small-
angle
crab c
avity
Q0 quad’s
l* = 22 m
Magnets
embedded
in the e
xpt.
apparatu
s
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannW. Scandale/F. Zimmermann, 19.03.2007
challenges: •D0 dipole deep inside detector (~3 m from IP),
•Q0 doublet inside detector (~13 m from IP & slim magnet technology),
•crab cavity for hadron beams (emittance growth ?),
•4 parasitic collisions at 4-5 separation,•“chromatic beam-beam” Q’eff ~ z/(4*),
•poor beam and luminosity lifetime ~ *
merits:•negligible long-range collisions,
•reduced geometric luminosity loss,
•no increase in beam current beyond ultimate
25-ns scenario assessment (accelerator
view point)
Name Event DateName Event Date1212
W. Scandale/F. Zimmermann, 13.02.2007
50-ns high intensity upgrade 50-ns high intensity upgrade scenarioscenario
double bunch spacingdouble bunch spacing
longer & more intense bunches with longer & more intense bunches with ffPiwinskiPiwinski~ 2~ 2
keep keep *~25 cm (achieved by stronger *~25 cm (achieved by stronger low-low- quads alone) quads alone)
do not add any elements inside do not add any elements inside detectorsdetectors
long-range beam-beam wire long-range beam-beam wire compensation compensation
novel operating regime for hadron novel operating regime for hadron colliderscolliders
(W. Scandale, F.Zimmermann & PAF)
add early-separation dipoles, one at ~ 5 m, the other at ~ 9 add early-separation dipoles, one at ~ 5 m, the other at ~ 9 m from IPm from IP Reduce the current Reduce the current Almost head-on crossing angleAlmost head-on crossing angle
Variant (not yet studied)
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannW. Scandale/F. Zimmermann, 19.03.2007
CMS & ATLAS IR layout for 50-ns option
long bunches & nonzero crossing angle & wire compensation
wire
compensator
stronger triplet magnets
l* = 22 m
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannW. Scandale/F. Zimmermann, 19.03.2007
merits:• no elements in detector, no crab cavities,
• lower chromaticity,
• less demand on IR quadrupoles (NbTi possible)challenges:
• operation with large Piwinski parameter unproven for hadron beams,
• high bunch charge,
• beam production and acceleration through SPS,
• “chromatic beam-beam” Q’eff ~ z/(4*),
• larger beam current,
• wire compensation (established last validation in RHIC)
50-ns scenario assessment (accelerator view point)
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannW. Scandale/F. Zimmermann, 19.03.2007
IR upgrade optics“compact low-gradient” NbTi, *=25 cm
<75 T/m (Riccardo De Maria, Oliver Bruning)
“modular low gradient” NbTi, *=25 cm <90 T/m (Riccardo De Maria, Oliver Bruning)
“low max low-gradient” NbTi, *=25 cm <125 T/m (Riccardo De Maria, Oliver Bruning)
standard Nb3Sn upgrade, *=25 cm ~200 T/m, 2 versions with different magnet parameters(Tanaji Sen et al, Emmanuel Laface, Walter Scandale)
+ crab-waist sextupole insertions? (LNF/FP7)include sextupoles to compansate the glass-hours effect
early separation with *=8 cm, Nb3Sn includes D0; either triplet closer to IP; being prepared for PAC’07 (Jean-Pierre Koutchouk et al)
Use of Q0being finalized for PAC’07 (E. Laface, W.Scandale)
compatiblewith50-nsupgradepath
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannW. Scandale/F. Zimmermann, 19.03.2007
crab waist scheme
⎟⎟⎠
⎞⎜⎜⎝
⎛−=
cyI
xpH
θ
2
4
1 2
minimizes at s=x/c
focal plane
realization:add sextupoles at right phase distance from IP
initiated and led by LNF in the frame of FP7;first beam tests at DAFNE later in 2007
Hamiltonian
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannW. Scandale/F. Zimmermann, 19.03.2007
25 ns spacing
50 ns spacing
IP1& 5 luminosity evolution for 25-ns & 50-ns spacing
averageluminosity
initial luminosity peakmay not be useful for physics
Turnaround time 10hOptimized run duration
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannW. Scandale/F. Zimmermann, 19.03.2007
25 ns spacing
50 ns spacing
IP1& 5 event pile up for 25-ns and 50-ns spacing
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannW. Scandale/F. Zimmermann, 19.03.2007
new upgrade bunch structures
25 ns
50 ns
nominal
25 ns
ultimate& 25-ns upgrade
50-ns upgrade,no collisions @S-LHCb!
50 ns
50-ns upgradewith 25-ns collisionsin LHCb
25 ns
new altern
ative!
new baseli
ne!
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannF. Zimmermann, W. Scandale, 19.03.2007
S-LHCb collision parametersparameter symbol 25 ns, offset 25 ns, late collision 50 ns, satellites
collision spacing Tcoll 25 ns 25 ns 25 ns
protons per bunch Nb [1011] 1.7 1.7 4.9 & 0.3
longitudinal profile Gaussian Gaussian flat
rms bunch length z [cm] 7.55 7.55 11.8
beta* at LHCb [m] 0.08 3 3
rms beam size x,y* [m] 6 40 40
rms divergence x’,y’* [rad] 80 13 13
full crossing angle c [urad] 550 180 180
Piwinski parameter cz/(2*x*) 3.3 0.18 0.28
peak luminosity L [1033 cm-2s-1] 1.13 2.1 2.4
effective luminosity (5 h turnaround time) Leff [1033 cm-2s-1] 0.25 0.35 0.67
initial lumi lifetime L [h] 1.8 2.8 9
length of lum. region l [cm] 1.6 5.3 8.0
rms length of luminous region:
€
1
σ l2
≈2
σ z2
+θ c
2
2σ *x,y2
⎛
⎝ ⎜ ⎜
⎞
⎠ ⎟ ⎟
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannF. Zimmermann, W. Scandale, 19.03.2007
luminosity leveling in IP1&5
experiments prefer more constant luminosity, less pile up at the start of run, higher luminosity at end
how could we achieve this?
50-ns higher- scheme:dynamic squeeze, and/ordynamic reduction in bunch length (less invasive)
25-ns low- scheme: dynamic squeeze orNovel proposal under investigation based on the change the crossing angle (G. Sterbini)
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannF. Zimmermann, W. Scandale, 19.03.2007
constLL ≈= 0constn
LXingevents
b
inel ≈=0/
beam intensitydecays linearly
length of run average luminosity
leveling equations
€
N = N 0 −L0σ totnIP
nb
t
€
trun =ΔN maxnb
Lσ tot nIP
€
Lave =L0
1+L0σ tot nIP
ΔN maxnb
Tturn−around
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannF. Zimmermann, W. Scandale, 19.03.2007
25 ns, low *,with leveling
50 ns, long bunches, with leveling
events/crossing 300 300
run time N/A 2.5 h
av. luminosity N/A 2.6x1034s-1cm-2
events/crossing 150 150
run time 2.5 h 14.8 h
av. luminosity 2.6x1034s-1cm-2 2.9x1034s-1cm-2
events/crossing 75 75
run time 9.9 h 26.4 h
av. luminosity 2.6x1034s-1cm-2 1.7x1034s-1cm-2
assuming 5 h turn-around time
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannF. Zimmermann, W. Scandale, 19.03.2007
25 ns spacing
50 ns spacing
IP1& 5 luminosity evolution for 25-ns & 50-ns spacingwith leveling
averageluminosity
PAF/POFPA Meeting 20 November 2006LHC Upgrade Beam Parameters, Frank ZimmermannF. Zimmermann, W. Scandale, 19.03.2007
25 ns spacing
50 ns spacing
IP1& 5 event pile up for 25-ns and 50-ns spacingwith leveling
Name Event DateName Event Date2626
W. Scandale/F. Zimmermann, 13.02.2007
summary summary • two scenarios of L~10two scenarios of L~103535 cm cm-2-2ss-1-1 for which for which heat load and #events/crossing are heat load and #events/crossing are acceptableacceptable
• 25-ns option25-ns option: pushes : pushes *; requires slim *; requires slim magnets inside detector, crab cavities, magnets inside detector, crab cavities, & high gradient large aperture (Nb& high gradient large aperture (Nb33Sn) Sn) quadrupolesquadrupoles and/or Q0 doublet; and/or Q0 doublet; attractive if total beam current is attractive if total beam current is limited; transformed to a 50-ns spacing limited; transformed to a 50-ns spacing by keeping only 1/2 the number of by keeping only 1/2 the number of bunches bunches
• 50-ns option:50-ns option: has fewer longer bunches has fewer longer bunches of higher charge ; can be realized with of higher charge ; can be realized with NbTi technologyNbTi technology if needed ; compatible if needed ; compatible with LHCb ; open issues are with LHCb ; open issues are SPS upgrade SPS upgrade & beam-beam effects at large Piwinski & beam-beam effects at large Piwinski angleangle; luminosity leveling may be done ; luminosity leveling may be done via bunch length and via via bunch length and via * tuning* tuning
Name Event DateName Event Date2727
W. Scandale/F. Zimmermann, 13.02.2007
recommendationsrecommendations•luminosity levelingluminosity leveling should be should be seriously considered in all cases: seriously considered in all cases: • more regular flow of eventsmore regular flow of events• moderate decrease in average moderate decrease in average
luminosityluminosity
•long-bunch 50-ns option entails long-bunch 50-ns option entails less riskless risk and less uncertainties; and less uncertainties; however with the drawback of the however with the drawback of the larger bunch populationlarger bunch population
•25-ns option is an optimal back up25-ns option is an optimal back up until we have gained some until we have gained some experience with the real LHC experience with the real LHC
•concrete optics solutionsconcrete optics solutions, , beam-beam-beam tracking studiesbeam tracking studies, and , and beam-beam-beam machine experimentsbeam machine experiments are needed are needed for both scenarios for both scenarios
The VLHC versus the LHC energy upgrade
LHC VLHC (20 01)
nominal dou bler tr ipler Sta ge 1 Sta ge 2
Peri me te r , km 26. 7 233
CM Ener gy, TeV 14 28 42 40 175
Dipole f ie ld, T 8 .4 16.8 25. 2 2 10
S upercon ductor Nb Ti Nb 3Sn HTS Nb Ti Nb 3Sn
Fermilab-TM-2149June 11, 2001
www.vlhc.org
Design Study for a Staged Very Large Hadron Collider
Build a long tunnel.Fill it with a “cheap” 40 TeV collider.Later, upgrade to a 200 TeV collider in the same tunnel.– Spreads the cost – Produces exciting energy-frontier physics sooner & cheaper
– Allows time to develop cost-reducing technologies for Stage 2
– vigorous R&D program in magnets and underground construction required.
•This is a time-tested formula for success
Main Ring TevatronLEP LHC
The two Stages of the VLHC
Stage 1 Stage 2
Total Circumference (km) 233 233
Center- of- Mass Energy (TeV) 40 200
Number of interaction regions 2 2
Peak luminosity (cm- 2s- 1) 1 x 1034 2.0 x 1034
Dipole field at collision energy (T) 2 11.2
Average arc bend radius (km) 35.0 35.0
I nitial Number of Protons per Bunch 2.6 x 1010 5.4 x 109
Bunch Spacing (ns) 18.8 18.8
* at collision (m) 0.3 0.5
Free space in the interaction region (m) ± 20 ± 30
Interactions per bunch crossing at Lpeak 21 55
Debris power per IR (kW) 6 94
Synchrotron radiation power (W/m/beam) 0.03 5.7
Average power use (MW) for collider ring 25 100
Parameters of the VLHC
Cost estimate ~ 4 G$o no detectors (2 halls included), o no EDI, o no indirect costs, o no escalation, o no contingency
2001 prices and c.a. 2001 technology. o No cost reduction assumed from R&D o Cost almost independent of the
choice of the B-field
Stage-1 at 40 TeV and 1034 luminosityo large tunnel to be build in the Fermilab area
o total construction time ~ 10 years
o Logistics and management complex
o only 20 MW of refrigeration power, comparable to the Tevatron.
o significant money and time saving by building the VLHC at FNAL
Cost drivers for the stage-1 (at FNAL)
30cm support tube/ vacuum jacketCryo-lines
100kA return bus
vacuum chambers
SC transmission line(100 kA)
2-in-1 warm iron
Superferric: 2T B- field
100kA Transmission Line
Combined function dipole (no quadrupoles needed)
65m Length
Self-contained including Cryogenic System and Electronics Cabling
Warm Vacuum System
Transmission line magnet for Stage-1
The Stage-2 VLHC can reach 200 TeV and 2x1034 or possibly significantly more in the 233 km tunnel. o A large-circumference ring is a great advantage for Stage-2
o A high-energy, high B-field (B > 12 T) VLHC in a small-circumference ring may not be realistic (too much synchrotron radiation).
o To demonstrate feasibility and to reduce cost, there is the need for R&D in the following items
high-field magnet,
vacuum in presence of large radiated power
efficient tunneling
photon stopper.
Stage-2
Superconducting magnets based on Nb3Sn
Stage-2 Dipole Single-layer common coil
Stage-2 Dipole Warm-iron Cosine Q
Magnets for Stage-2
Synchrotron radiation
Beam screen
There is an optimal size of the coolant pipe and of the beam screen temperature for a given synchrotron emission regime
€
Eturn =e2
3ε 0
β 3
r
E
m0c2
⎛
⎝ ⎜
⎞
⎠ ⎟
4
Synchrotron radiation masks look promising.
Preliminary tests already performed at FNAL.
They will decrease refrigerator power and permit higher energy and luminosity.
They are practical only in a large-circumference tunnel.
BEAM SCREEN
SLOT
GAP
PHOTON-STOP
Photon stoppers
PSR<10 W/m/beam peak
tL > 2 tsr
Interaction per cross < 60
L units 1034 cm-2s-1
Optimum Dipole Field
€
Eturn =e2
3ε 0
β 3
r
E
m0c2
⎛
⎝ ⎜
⎞
⎠ ⎟
4
The cutoffs are field too low, not enough damping, field too high, too much synchrad power so required aperture too large.
Luminosity scale
LHC energy doubler 14*14 TeV dipole field Bnom = 16.8 T, Bdesign = 18.5-19.3 T
(10-15% margin)
o superconductor - Nb3Sn
o 10-13 T field demonstrated in several 1-m long Nb3Sn dipole models
o DLHC magnet parameters well above the demonstrated Nb3Sn magnet technology
R&D and construction time and cost estimates o 10+ years for magnet technology development and demonstration
o Magnet production by industry ~ 8-10 years
o High cost for R&D and construction (cost of dipoles > 3GCHF ?)
LHC energy tripler 21*21 TeV
dipole field Bnom = 25 T, Bdesign = 28-29 T (10-15% margin)
o superconductor - HTS-BSCCO (low demand) or Nb3Sn
o Magnet technology to be fully demonstrated
o DLHC magnet parameters well above the demonstrated Nb3Sn magnet technology
Large aperture dipole to accommodate an efficient beam screen
R&D and construction time and cost/risk estimates o 20++ years for magnet technology development and
demonstrationo Extremely high R&D and construction cost and risk
SC cable to be developed, Magnetic coil stress requires innovative dipole cross section
o Magnet production by industry (?) ?? years
LHC, sLHC, DLHC perspective
VLHC perspective