G.W. Foster AAC May 2001 1
VLHC Design StudyTechnical Aspects
G.W. FosterMay ‘01
G.W. Foster AAC May 2001 2
OUTLINE
• Stage 1 Magnets• Cryogenics (Stage 1 and Stage 2)• (PJL → Stage 2 Magnets & Synch Rad)• Stage 1 Subsystems• Beam Abort & Radiation Considerations
G.W. Foster AAC May 2001 3
Transmission Line Magnet
• 2-in-1 warm iron warm bore superferric• alternating gradient (no quads)• 100kA Transmission Line• all-piping cryogenic system
230
660 REF.
SUPERCONDUCTINGTRANSMISSION LINE
100 kA RETURN BUS
CRYOPIPES
VACUUMCHAMBER
Support Tube /Vacuum Jacket
G.W. Foster AAC May 2001 4
Corrector Region (every 135m)
G.W. Foster AAC May 2001 5
VLHC-1 Magnet Summary
Magnet Type Bnom (T) Gnom (T/m) Lmag (m) Number ofelements
Notes
Gradient dipole (arc) 1.97 9.73 67.75 3136 Main Arc MagnetsGradient dipole (DS) 1.80 16.88 48.81 160 Dispersion SuppressorsStraight sect quads 70 4.8 - 6.8 464 Room temp. conventionalLow β quadrupoles 300 9.2 - 10.9 8 Supercond. IR QuadsSpecial dipoles 1.95 25 - 35 52 Separation, recombination,
and cross-overCorrectors Air-cooled Iron/Copper
Dipole (horiz.) 1.0 0.50 1648 Every “F” locationDipole (vert.) 1.0 0.50 1648 Every “D” locationQuadrupole 25 0.50 3296 Every F&D locationSextupole 1750 T/m2 0.80 3296 Every F&D location
G.W. Foster AAC May 2001 6
Main Dipole MagnetsMain Arc Dipole Dispersion Suppressor
Magnet air gap in the orbit center 20 mm 22.26 mmBeam Pipe Inner Dimensions 18 mm x 28 mm (elliptical)Separation Between Beams 150 mmMagnet length 65.74 m 48.81 mHalf-cell length 135.5 m 101.6 mSagitta in Magnet 1.6 cm 0.6 cmGradient ± 4.73 %/cm ± 9.449%/cm
injection 0.1 T 0.09 TMagnetic field:maximum 1.966 T 1.766 Tinjection 20 mmGood field diameter
(< 0.02%): maximum 10 mmTransmission Line Design Current 100 kACurrent at 20 TeV 87.5 kAMagnetic field energy @100 kA 790 kJ (12 kJ/m) 473 kJ (10 kJ/m)Superconducting cable Braided NbTi with Braided Cu StabilizerSpecified Max. Temp of Conductor 6.5-6.7 KNominal Max Temp of Cryo System 6.0 KIron Core 1 mm Laminated low carbon Steel (AISI 1008 or better)
G.W. Foster AAC May 2001 7
Why 65m Magnets?• Other Reasonable choices will work:
– 1/8 cell (38m), 1/2 Cell (135m)• Weight = 33 tons, similar to LHC = 35 tons• 65m Magnet can have lifting fixture
– pick magnet by 2 points, fixture fits in tunnel• All cables can be factory installed on 65m
– but not on shorter (1/8 cell) magnets• Tunnel labor for splicing ~$10M• Cryo load from splices ~10% of 4.5K load• Factory ~1.5x size for 2x length magnets
G.W. Foster AAC May 2001 8
2-D Magnetic and Mechanical• Upper & Lower
half-cores welded together
• Gap spacer from nonmagnetic 316L
• 1 mm laminations• Holes in poles to
control saturation sextupole and gradient shift
G.W. Foster AAC May 2001 9
B vs. Current
• 1.966 Tesla (=20 TeV) at 87.5 kA. • Transmission line design current is 100 kA.
0
0.5
1
1.5
2
0 20 40 60 80
I (kA)
B (
T)
G.W. Foster AAC May 2001 10
Control of Saturation Sextupole
• Need correctors above ~1.8T• No loss of dynamic aperture at 1.966T
Effect of Slots on Saturation Sextupole(Field Shape change between 1.8T and 1.25T)
-25
-20
-15
-10
-5
0
5
-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1
X (cm)
Diffe
renc
e in
Fie
ld S
hape
at 1
.8T
and
1.3T
(x 1
E4)
No Slots (Calculated)
With Slots (Calculated)With Slots (Measured) file:my0z1-00
G.W. Foster AAC May 2001 11
Control of Gradient Shift
• Correctors sized to regulate tune and β up to design field of 1.966T.
Gradient Shift vs. BWith and Without Slots in the Poles
-25
-20
-15
-10
-5
0
5
0 0.5 1 1.5 2 2.5B (Tesla)
Gra
dien
t (un
its @
1cm
) m
inus
Gra
d@1.
25Te
sla
Slots in Pole (Calculated)
No Slots (Calculated)
Measured with Slots file: my0z1-00
G.W. Foster AAC May 2001 12
Transmission Line Design Requirements
• Enough NbTi to carry 100kA at 6.5K, 1T– (includes margin: TNOM= 6.0K, INOM=87.5kA)
• 2.5cm clear bore for He transport 9.5 km• Enough Cu to survive quench with τ = 1 sec• Withstand 35 Bar quench pressure• Conductor centered +/- 0.5mm• Low heat leak: < 50mW/m• Survive cooldown with ends constrained
⇒ Invar™ transmission line piping
G.W. Foster AAC May 2001 13
G.W. Foster AAC May 2001 14
Three Transmission Line Variants
BRAIDED CONDUCTOR(Drive and Current Return)
Drive Bus Return Bus Bus in Corr. Space
Cu/SC ratio in strand 1.8 1.8 1.3
Diameter (mm) 0.648 0.648 0.808
Cond. Type Braid Braid 9 Rutherford Cables
Number of strands 288 288 270
Cu Wire dia. (mm) 0.64 0.64 0.64
Number of wires 240 288 288
Inner Pipe ID .(mm) 25.3 36.8 36.8
Outer Pipe OD (mm) 38.1 47.1 50.1
Max working Pressure (bar) 40 40 40
RUTHERFORD CONDUCTOR(Corrector Region)
G.W. Foster AAC May 2001 15
Operating Margin
Tm
ax =
6.1
K
Iop = 90 kA
0.7 K Margin
0
20
40
60
80
100
120
140
0 2 4 6 8Temperature (K )
Cur
rent
(kA
)
~ 0.7°K margin at design current of 87.5 kA~ 25kA margin at nominal peak temperature of 6.0 K
The design trades extra superconductor ($50M total) for simpler cryo ($110M)
G.W. Foster AAC May 2001 16
What is most cost-effective Operating Temperature?Tradeoff: Refrigeration vs. Superconductor Costs
TOTAL(Cryo + SC)
Cryo System CostScaled by Carnot
NbTi Conductor
52,800 kA-mat 1 Tesla
DesignPoint
0
50
100
150
200
250
4 4.5 5 5.5 6 6.5 7 7.5 8 8.5
Peak Operating Temperature (deg K)
Cost
Com
pone
nt ($
M)
G.W. Foster AAC May 2001 17
Mechanical Issues
• Gravitational Sag• Force and Stresses from adjusters• Gap Stability under magnetic forces• Cold-to-warm forces on spider• longitudinal forces, bellows, interconnects
G.W. Foster AAC May 2001 18
Longitudinal Forces
• All pipes anchored to ground every 135m• Transmission line pipes are Invar• Other Cryo pipes have bellows• Vacuum jackets have anchors & bellows
every 135m• Designated break points for coolant accidents
G.W. Foster AAC May 2001 19
Magnet Ends
• Dog-leg transmission line downwards to provide field-free region for correctors
• Handle large forces between conductors with cold-to-cold structural connection
G.W. Foster AAC May 2001 20
Corrector Magnets • Dipole, quad, and 6-pole correctors every half-cell• Dipole correctors: full aperture scan @3 TeV• Quadrupole: corrects gradient shift at 1.96T• 6-pole: corrects saturation sextupole at 1.96T• correctors independently powered to correct for
systematic & random errors in arc magnets
G.W. Foster AAC May 2001 21
Orbit Corrector StrengthNumber of Magnet Moves vs. Time
to Maintain Closed Orbit Distortion at Flat-topWithin Various Tolerances
Perfect Closed Orbit
0.1 mm Peak COD
0.5 mm Peak COD
1.0 mm Peak COD
2.0 mm Peak COD
Corrector Bend 7.5 urad
B*L = 0.5 T-m at 20 TeV
0.25mm RMS Survey Err
1mrad Dipole Roll
dB/Bo = 3E-4
270m x 90 Degree Cells
1 H/V Corrector/halfcell
ATL const 5E-6
Circumference 225km
0
20
40
60
80
100
120
140
160
180
200
0 1 2 3 4 5 6 7 8 9 10
Years Since Initia l Insta lla tion
Num
ber
of M
agne
ts M
oved
G.W. Foster AAC May 2001 22
Corrector SummaryCorrector type Horizontal
DipoleVerticalDipole
Quadru-pole
Sextupole
Quantity 1720 1720 3136 3136
Maximum magnet strength 1.0 T 1.0 T 25 T/m 1750 T/m²
Field quality, 18 mm diameter area, % 1.0 1.0 1.0 1.0
Effective magnet field length, m 0.5 0.5 0.5 0.8
Integrated field at r = 1 cm, T-m 0.5 0.5 0.125 0.14
Magnet core length, m 0.48 0.48 0.5 0.8
Current, A 25 25 1.0 1.0
Voltage, V 23 23 140 175
Power, W 600 600 150 200
Number of coils per magnet 1 1 4 6
Number of turns per coil 640 640 1240 633
Copper conductor diameter, mm 5 x 5 5 x 5 1 1
Copper weight, kg 250 250 40 50
Core weight, kg 300 220 30 50
G.W. Foster AAC May 2001 23
IR Magnets for Stage 1• 300 T/m• 85mm aperture• 4.5K Nb3Sn• Synergy w/ LHC
upgrade quads• LHC-like layout• All other IR
magnets use warm iron
G.W. Foster AAC May 2001 24
Straight Section Quads
• Warm magnets chosen for cost & integration• Fit side-by-side on 150mm beam centers
G.W. Foster AAC May 2001 25
CRYOGENICS
• Stage 1: 6 Plants, each [email protected] equiv– 12 MW total wall power (17MW installed)– ~15% additional for SCRF option, IR’s etc.– Installed power 150% of nominal
• Stage 2: 12 Plants, each [email protected] equiv.– 85 MW total Wall Power (113 MW installed)– ~3.5x LHC
G.W. Foster AAC May 2001 26
Split ColdboxRing Layout
40 km
G.W. Foster AAC May 2001 27
Piping in Transmission Line Magnet
Vacuum Jacket(Aluminum Extrusion)
Transmission Line1.5" OD / 1.1" IDInvar + Cu + NbTi
Magnet Support Tube& Cryo Vacuum Jacket12" OD x 0.25" WallCarbon Steel
BeamPipes
Flow Return for FarTransmission Line(1st half-loop only)
Shield ReturnHeader 3" Invar tube
Shield Supply Header3" x 0.050" WallInvar Tube
Current Return Bus2.5" OD / 2.1" IDInvar + Cu + NbTi
70K40K
4.5K
6.5K
40-60K Shield Traces2 x 0.25" Invar Tubes
4.5K
Warm Iron
300K
Warm GasReturn Header6" PipeOn Tunnel Wall
G.W. Foster AAC May 2001 28
4.5K-6K Supercritical Flow
G.W. Foster AAC May 2001 29
40km Sector LayoutRefrigerator
Helium Pressure Relief Valves
G.W. Foster AAC May 2001 30
Stage 1 Heat Loads
Primary 4.5K Secondary 40KSTATIC
Near LoopMechanical Supports, [mW/m] 53 670Superinsulation, [mW/m] 15 864
Far LoopMechanical Supports, [mW/m] 53 670Superinsulation, [mW/m] 13 864
DYNAMICBeam Loss, [mW/m] 2 1Superconductor Splice, [mW/m] 7 -
G.W. Foster AAC May 2001 31
Transmission Line Cryostat
• Resist Vertical Decentering Force• Low Heat Leak
G.W. Foster AAC May 2001 32
Stage 1 Ring Cryogenics Summary Shield
Near Loop Far Loop Near Loop Far Loop
Temp in [K] 4.50 4.52 5.44 5.40 37.00Press in [bar] 4.00 3.80 2.00 2.50 17.00Enthalpy in [J/g] 12.09 12.09 33.92 27.18 207.28Entropy in [J/(g*K)] 3.52 3.56 8.19 6.69 14.76Temp out [K] 5.57 5.39 5.80 5.54 70.00Press out [bar] 2.80 2.50 1.90 2.10 13.00Enthalpy out [J/g] 26.40 26.66 37.79 34.24 381.66Entropy out [J/(g*K)] 6.44 6.59 8.96 8.18 18.71Predicted heat load [W/m] 0.044 0.044 0.024 0.022 1.534Distance [m] 19400 19400 19400 19400 38800Design total heat [kW] 0.85 0.85 0.47 0.43 60Mass flow [g/sec] 60 59 120 60 341Design ideal power [kW] 103 107 27 53 345
Magnets ShieldPredicted heat load [kW] 2.6 60Heat uncertainty factor [-] 1.25 1.25Design Heat Load [kW] 3.2 74Design mass flow [g/sec] 120 348Design ideal power [kW] 291 3454.5 K equiv design power [kW] 4.43 5.26Efficiency (fraction Carnot) [-] 0.28 0.28Nominal operating power [kW] 1039 1233Overcapacity factor [-] 1.3 1.3Installed operating power (kW) 1351 1603
Operating wall plug power for one sector (MW) 2.0Installed wall plug power for cryogenics for one sector (MW) 3.0Operating wall plug power for cryogenics for entire accelerator (MW) 11.8Installed wall plug power for cryogenics for entire accelerator (MW) 17.7
MagnetsTransmission Line Current Return Bus
IR’s and RF add ~10kW to
on-site load.
(May cover this with CHL since Tevatron is not
ramping)
G.W. Foster AAC May 2001 33
Stage 2 Cryogenics
dQdQ fQ
Tom Peterson19 March 2001High Field VLHC cell flow concept with S. Zlobin electrical scheme
5.5 K, 1.8 bar helium return and quench header
Quench and cooldown valveShield and beam screen flow valve
80 K, 20 bar helium thermal shield supply and beam screen supply
110 K, 17 bar helium shield return flow and transfer line shield
4 IPS (11 cm) pipe
5 IPS (14 cm) pipe
6 IPS (17 cm) pipe
One 270 meter cell
Transfer line
D D D D D DD D
4.5 K, 4 bar magnet helium flow
Magnet cryostat1.5 inch (3.8 cm) tube
D D D D D D
80 K to 90 K thermal shield
90 K to 110 K beam screens
C C C
Four 25 kA bus in 4 IPS (11 cm) helium pipe
Jumper connections
Dipole bus and coil leads
Defocussing quad bus and coil leadsFocussing quad bus and coil leads
Spool LargeSpool
Spool
300 K, 1.2 bar helium gas return Relief and cooldown valve
6 IPS (17 cm) pipe
26 inch (66 cm) OD transfer line vacuum shell
D D D
Pipe includes 4.5 K, 4 bar helium flow parallel to magnet flow
(Include vacuum breaks)
36 inch (92 cm) magnet cryostat vacuum shell
G.W. Foster AAC May 2001 34
Stage 2 Cryogenics SummaryShield supply Shield return pipepipe Thermal shield Beam screen and thermal shield Magnet cold mass(in transfer line) (magnet) (two beams) (transfer line)
Temp in (K) 77.00 77.61 87.58 77.61 4.5Press in (bar) 20.0 19.4 19.3 18.1 4.0Temp out (K) 77.61 87.58 106.58 108.82 5.5Press out (bar) 19.4 19.3 18.1 17.7 1.8
Predicted heat load (W/m) 0.1 4.2 10.0 2.2 0.83Heat uncertainty factor 1.25 1.25 1.00 1.25 1.25Design heat load (W/m) 0.13 5.25 10.00 2.75 1.04Distance (m) 9700.0 9700.0 7824.0 9700.0 9700.0Design total heat (kW) 1.2 50.9 78.2 26.7 10.1Design mass flow (g/s) 1104.0 13.6 6.8 1104.0 422.7
Design ideal power (kW) 10.4 137.5 194.5 63.0 647.34.5 K equiv design power (kW) 0.2 2.1 3.0 1.0 9.9
Efficiency (fraction Carnot) 0.30 0.30 0.30 0.30 0.30Efficiency in Watts/Watt (W/W) 28.7 9.0 8.3 7.9 214.4Nominal operating power (kW) 34.8 458.2 648.5 210.1 2157.6
Overcapacity factor 1.30 1.30 1.30 1.30 1.30Installed operating power (kW) 45.2 595.7 843.0 273.1 2804.8
Percent of power 1.0% 12.6% 17.9% 5.8% 59.4%
Total installed operating power for one 10 km string (MW) 4.7Total installed 4.5 K equivalent power for one 10 km string (kW) 21.2
Number of above "strings" in accelerator 24Operating wall plug power for cryogenics for entire accelerator (MW) 85.7Installed wall plug power for cryogenics for entire accelerator (MW) 113.3Installed 4.5 K equivalent power for entire accelerator (kW) 508.9Installed number of LHC system equivalents 3.5
G.W. Foster AAC May 2001 35
Radiofrequency Systems(Sergey Belomestnykh)
Stage 1 Stage 2Acceleration Storage Acceleration Storage
Beam current 190 mA 68.9 mABeam energy 0.9 – 20 TeV 20 TeV 10 – 87.5 TeV 87.5 TeV
Acceleration time 1000 sec 2000 secAcceleration per turn 14.8 MV 39.4 – 18.15 MV
Acceleration power (2 beams) 5.62 MW 4.134 MWSynch. rad. loss per turn 0.03 MeV 12.37 MeV
Total s.r. power (2 beams) 13 kW 2.1 MWRevolution frequency 1286.5 Hz
Bunch length, rms 142 mm 66 mm 81.9 mm 33.7 mmSynchrotron tune 0.00845 0.00179 .00280 .00189
Synchrotron frequency 10.87 Hz 2.30 Hz 3.60 Hz 2.43 HzBunch frequency 53.1 MHz
Number of buckets 41280Bunch spacing 5.646 m, 18.8 ns
RF harmonic number 288960RF frequency (7×53.1) 371.7 MHz
RF wavelength 80.65 cmRF voltage 50 MV 50 MV 50 MV 200 MV
Accelerating gradient 7.75 MV/mVoltage per cavity 3.125 MV
R/Q 89 OhmQ factor at 8 MV/m 2×109
Number of cavities 32 (16+16) 128 (64+64)Cavities per cryostat 4RF cavity wall losses 55 W
Cryostat static heat leak 60 WTotal cryogenic heat load 2.24 kW 8.96 kWBeam power per cavity 176 kW 0.406 kW 42.4 kW peak 16.4 kW
Number of 500 kW klystrons 16 (8+8) 16 (8+8)Number of cavities per klystron 2 8
• Either Warm Copper or SC RF systems are possible
• Superconducting RF chosen for Design Study
• Need to integrate coalescing cavities (if needed).
G.W. Foster AAC May 2001 36
Ramp Optimization - Stage 2 Ramp for High Field Ring
0
5
10
15
20
25
30
35
40
45
50
0 500 1000 1500 2000 2500
Ramp Time (sec)
Pow
er S
uppl
y Cu
rren
t(kA)
, Po
wer
Sup
ply
Tota
l Vol
tage
(kV)
,RF
Ram
ping
Vol
tage
(MV/
turn
)or
Pow
er P
er S
exta
nt (M
W)
RF accelerating MV/Turn
PS Pow er per Sextant (MW)
PS Voltage (kV total)
PS Current (kA)
Voltage Limitedfor first 35% of Ramp
Magnet Power Limited for rest of Ramp.
Stage 1 is always
RF Limited
G.W. Foster AAC May 2001 37
Power Supplies, Quench Protection,and Current Leads - Stage 1
TransmissionLine Power
Supply
IR QuadrupolePower Supplies
(sect 5.1.4)
Straight sectionWarm MagnetPower Supplies
CorrectorMagnets
(warm copper)Number 1 2 16 approx. 12,000Location FNAL at Experiments Straights Quad locationsVoltage per supply 62 10V typ. 1000V typ. 100 TypCurrent per supply 100kA 25kA 200A typ 2A typRamping MVA (tot) 6.2 MVA 1 MVA - -DC Power (total) 0.4 MW 0.6 MW 7.4 MW 2.1 MWLCW Consumption - - 150 liters/sec (air cooled)Quench Detection 1 Circuit at PS 2 circuits/quad - -Quench Protection Dumps @ 20km 4 heaters/quad - -SC Current leads 100kA-pair 60kA-pair - -
Peak RampingSupply Power 17.7 MW
Total Power SupplyPower in Collision 10.5 MW
G.W. Foster AAC May 2001 38
G.W. Foster AAC May 2001 39
100kA MAIN DIPOLE POWER SUPPLY
• Single Supply on-site at FNAL• Above or Underground?• 6.2 MVA ~1/6 of Main Injector• +/-62V ramps magnets in 1000 secs• Actually 2 supplies in series:
1) +/-62V Ramping Supply (SCR)2) +2.5V Precision Holding Supply
G.W. Foster AAC May 2001 40
• 12-phase SCR Bridge• 2 Quadrant Operation• Parallel 8.5kA modules similar to FMI
RAMPING POWER SUPPLY
G.W. Foster AAC May 2001 41
HOLDING POWER SUPPLY
• +2.5V Single Quadrant Operation• Overcomes Series Drops in busswork,
SC leads, Splices, and SCR Bypass Switch• 2 KHz Switching supply• Parallel ten 10kA modules• Stagger Phasing of modules to reduce ripple• Synchronize to Revolution Frequency to
eliminate emittance growth from noise
G.W. Foster AAC May 2001 42
100kA Power Supply and Current Leads
G.W. Foster AAC May 2001 43
100kA Power Supply Assembly for MP6 String Test
G.W. Foster AAC May 2001 44
Stability Against Quenches From Beam Losses
• Full shower development and energy deposition calculated (Mokhov).
• Warm iron design can tolerate ~20x more beam loss than conventional cold-bore magnet, probably more.
Beam Loss Points
G.W. Foster AAC May 2001 45
Magnetic EnergyDump System - Stage 1
• 10kJ/m stored energy in magnet requires active energy dump.
• 2 GJ Stage 1 vs. 10 GJ LHC • When quench detected, current diverted to
series dump resistor to extract magnetic energy.
• 1 second dump time reasonable.• Practical limit +/-3kV to ground
G.W. Foster AAC May 2001 46
VLHC Magnetic EnergyDump System
• Requires dump resistors and switches to be spaced ~20km.
0.06 Ohm
0.06 H
Quench Cell 20km Long
MagnetString
Dump Switchand Resistor
G.W. Foster AAC May 2001 47
Advantages of Superconducting Dump Switch
• Zero Power Dissipation.• Small heat leak (safety leads).• Easy to re-cool by venting He into warm gas
return.• No LCW.• Small quench trigger power ~1kJ.• Can be spaced far from utilities.
G.W. Foster AAC May 2001 48
Transmission Line Current 100 kAMagnetic Stored Energy @100kA 10 kJ/meter, 2100 MJ/ringMagnet Inductance at low field 3uH/m 600mH/ringEnergy Dump Time Constant 1 second
Peak Voltage To Ground during Dump ± 3 kVI2t during dump 5 x 109 Amp2SecondsPeak Temperature of Conductor During Quench 250KPeak Pressure of Helium During Quench 35 BarPressure relief during quench Every 2 cells (500m)
Effective Copper Cross Section of Conductor 3cm2
Quench Detection Threshold 1 VoltQuench Detection Method (primary) Analog bucking with midpoint of current return busQuench Detection Method (backup) Deviation from V=LdI/dt at power supply
terminals
Energy Dump Resistance 60 mΩ per location,Dump Switch Locations at cryoplants and midpoint of arc (20km spacing)Dump Switches Quenched superconducting cables 65m longSuperconducting Dump Switch Conductor 1:1 CuNi:NbTi “Switch Wire”Cryogenic Dump Resistor Thermal Mass 65m long x 20cm2 Thick Wall Invar pipeFinal Dump Temperature after Dump from 100kA 325KLHe Required for recovery after Dump from 100kA 1600 liters (less if shield flow used for pre-cooling)
Table 5.2.2.3 - Stage 1 Quench Detection and ProtectionParameters
G.W. Foster AAC May 2001 49
Power Dissipation and LCW Summary - Stage 1Heat Load Total Loads Total kW LCW Flow (l/min)
Resistive Magnets 188 4480 3200
Power Supply Cooling 22 500 600
RF Klystrons 16 3760 6400
RF Loads & Recirculators 16 5600 4500
Beam Stop 1 500 600
On-Site
Straight
Sections
Total (on-site) 227 14840 15300
Resistive Magnets 176 3320 3500
Power Supply Cooling 9 550 600
Beam Collimation - 40 50
Far Side
Straight
SectionsTotal (far side) 185 3910 4150
LCW Systems Total 412 18750 19150
G.W. Foster AAC May 2001 50
LCW System (FNAL Site)
PowerSupply
RFKlystron
Utility Straight
CryoBend
PowerSupply
IR1 Straight
CryoBend
CrossOver
CryoBend
Pump From Tunnel to Surface
IR2 Straight
CryoBend
PowerSupply
RFKlystron
Utility Straight
BeamDump
Main Ring Ponds and LCW System
3 km 3 km
Comparable to MI-60 LCW System of Fermilab Main Injector
G.W. Foster AAC May 2001 51
ARC INSTRUMENTATION• Electronics
modules each half-cell ~135m
• Shielded Coffin• Minimizes
Cables• Average Power
in Tunnel ~15W/m
• Mostly correctors
R 72 in
Ø6in
Electronics Module
Ø12.00in
G.W. Foster AAC May 2001 52
Local Electronics Modules
G.W. Foster AAC May 2001 53
Cabling Pre-Installed on MagnetELECTRONICS MODULE AT EACH ARC HALF-CELL (135m
G.W. Foster AAC May 2001 54
Power Distribution In Tunnel
1kV DC 100 kW
AC from Surface
RedundantBulk DC Suppliesin Walk-In AlcoveEvery 10 km
Control
CorrectorMagnets(6-8 total.)
RedundantDC-DCConvertersIn LocalElectronicsModulesEvery 135m
1kV DC 100 kW
Redundant 1kV DC Feeder Looping Ring
250W
1400W
G.W. Foster AAC May 2001 55
Beam Vacuum System(Turner, Pivi, Kennedy)
G.W. Foster AAC May 2001 56
Vacuum System
• Aluminum Extrusion is placed inside magnet core after bakeout and magnet test
• Vertically pre-loaded against laminations
• No in situ bakeout.
G.W. Foster AAC May 2001 57
Beam Lifetime During Vacuum Cleanup
0 20 40 60 80 1000
50
100
150
200
250
300
350
400
450
500
proton proton lifetime τpp
beam gas-scattering lifetime τg
Beam lifetime τb
Life
time
(hrs
)
Time (hrs)
~200-hour vacuum lifetime
after 5 stores
G.W. Foster AAC May 2001 58
Beam Pipe Apertures
20mm
Ø20mm
22mm
Ø50mmØ46mm Ø23 mm
40mm
Ø40mm
10mm20mm
28mm30mm
18mm
20mm
28mm
30mm
18mm20mm
28mm30mm
18mm20mm
QUADRUPOLEor Quad Corrector
ARC DIPOLEor Horiz. Corrector ( F location)
ARC DIPOLE ( D location)
Vertical Corrector ( D location)
STRAIGHT SECTION BEAM PIPE
SEXTUPOLE CORRECTOR(F & D Locations)
INJECTION LAMBERTSON LARGE APERTURE QUADNEAR INJECTION LAMBERTSON
G.W. Foster AAC May 2001 59
BPM SYSTEM
• Button Style Pickups
• ~ 5 m cable to readout electronics
• Either AM/PM conversion or Log Amps OK
Beam Position MonitorX & Y, “Button” style
Calibration can be verified in situwith independent quad correctors
G.W. Foster AAC May 2001 60
BLM SYSTEM
• Mission-Critical• Redundant:
– Two full-length BLMs per magnet
– Read-out at alternate halfcell locations
• Maintenance-Free Design
G.W. Foster AAC May 2001 61
Once-per-Turn Instrumentation
FUNCTION Occurances Readout Frequency CommentsTune Measurement a few/ring 10 Hz Use Arc Module DSP’s for FFT?Beam Current Toroids 1/ring Also on injection linesSampled Bunch Display 1/ring 1 Hz Fast Bunch Integrator 1/ring 1 Hz Synchrotron Light Monitor 1/ring 1 Hz Ion Profile Monitor 2/ring .1 Hz Small beam size may be challengingFlying Wires 1/ring ~few per store
• Can be mostly copied from Tevatron/MI systems• Easily fit into Warm Utility Straight Sections
G.W. Foster AAC May 2001 62
Beam Damper (Lambertson/Marriner)
D D D D D D D DF F F F F F F
KickerPickup KickerPickup
9ns PulseStretcher
Strip LinePickup Cable
Driver
270m Foam Coax Line
PA Kicker
90° Betatron Phase Advance between Pickup & Kicker
G.W. Foster AAC May 2001 63
Radiation and Beam Abort
• Beam energy can liquefy 400 liters of SS(LHC beams can only liquefy 50 liters)
• Three Qualitatively New Features:1) Beam Sweeper failure will damage dump
⇒ sacrificial plug upstream of dump.2) Beam Sweeper failure will melt hole in
window ⇒ close gate valve.3) Beam Cleaner Secondary Collimators
Must be Water Cooled ⇒ do it.
G.W. Foster AAC May 2001 64
Beam Abort
X-Y Sweeper Magnet
Sacrificial Absorber (for Sweeper Failure)
Spiral Sweep on Graphite Absorber Block
Lambertson
Beam Window
Aluminum, Steel, & Cement Sarcaphagus
Kicker
300m 3000 m
Circulating Beam
• Under normal circumstances the extracted beam beam is swept in a spiral pattern to spread the energy across the graphite dump.
• If the sweeper magnet fails, the beam travels straight ahead into a sacrificial graphite rod which takes the damage and must be replaced. Beam window also fails.
G.W. Foster AAC May 2001 65
Beam Collimation System(Drozhdin)
• Purpose-Built System works nearly perfectly
• 20kW power in secondary collimators (→ LCW)
G.W. Foster AAC May 2001 66
Worst-Case Beam Accident• 2.8 GJ ~ 8x LHC Beam Energy (400 liters SS)