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OPTIMIZED SOLENOID BASED CAPTURE MECHANISM FOR A MUON COLLIDER/NEUTRINO FACTORY TARGET SYSTEM HISHAM KAMAL SAYED BROOKHAVEN NATIONAL LABORATORY MAP COLLABORATION MEETING FERMILAB 2013
OPTIMIZED SOLENOID BASED CAPTURE MECHANISM FOR A MUON COLLIDER/NEUTRINO FACTORY TARGET SYSTEM
HISHAM KAMAL SAYED BROOKHAVEN NATIONAL LABORATORY
MAP COLLABORATION MEETING FERMILAB 2013
INTRODUCTION & LAYOUT
Muon Capture in Target & Front END
Ø Capture Solenoid Field Study: Ø Optimizing quantity: Muon (Pions) count – transverse capture
- Target Solenoid peak field - Final end field
Ø Optimizing quality: Muon (Pions) longitudinal phase space (transverse-longitudinal coupling) – transverse-longitudinal capture - Taper field profile
Ø Optimizing the time of flight of incident beam (Buncher-Rotator RF phase) Ø Transverse focusing field in decay-channel-buncher-rotator Ø Match to ionization cooling channel for every end field case 1.5 T à 3.5 T Ø Performance of front end as a function of proton bunch length Ø Realistic Coil Design & performance optimization
Hisham Sayed - MAP meeting 2013 6/20/13
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MUON COLLIDER/NEUTRINO FACTORY LAYOUT
Target System Solenoid: Capture µ± of energies ~ 100-400 MeV from a 4-MW proton beam (E ~ 8 GeV).
Hisham Sayed - MAP meeting 2013 6/20/13
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TARGET SYSTEM CURRENT BASELINE DESIGN
Ø Production of 1014 µ/s from 1015 p/s (≈ 4 MW proton beam)
Ø Proton beam readily tilted with respect to magnetic axis.
Ø Shielding of the superconducting magnets from radiation is a major issue.
SC magnets
Resistive magnets
Proton beam and Mercury jet
Tungsten beads
Mercury collection pool With splash mitigator
5-T copper magnet insert; 10-T Nb3Sn coil + 5-T NbTi outsert. Desirable to eliminate the copper magnet (or replace by a 20-T HTS insert).
Ø Hg Target Ø Proton Beam
Ø E=8 GeV Ø Solenoid Field
Ø IDS120h à 20 T peak field at target position (Z=-37.5) Ø Aperture at Target R=7.5 cm - End aperture R = 30 cm Ø Fixed Field Z = 15 m à Bz=1.5 T
Ø Production: Muons within energy KE cut 40-180 MeV end of decay channel
Ø Nμ+π+κ/NP=0.3-0.4
Hisham Sayed - MAP meeting 2013 6/20/13
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TAPERED TARGET SOLENOID OPTIMIZATION
0
5
10
15
20
0 5 10 15 20 25 30 35
Bz
[T]
z [m]
Ltaper= 5 [m]Ltaper=15 [m]Ltaper=25 [m]Ltaper=35 [m]
0
5
10
15
20
0 5 10 15 20 25 30 35
Bz
[T]
z [m]
Ltaper= 5 [m]Ltaper=15 [m]Ltaper=25 [m]Ltaper=35 [m]
0
5
10
15
20
0 5 10 15 20 25 30 35
Bz
[T]
z [m]
Ltaper= 5 [m]Ltaper=15 [m]Ltaper=25 [m]Ltaper=35 [m]
0
5
10
15
20
0 5 10 15 20 25 30 35
Bz
[T]
z [m]
Ltaper= 5 [m]Ltaper=15 [m]Ltaper=25 [m]Ltaper=35 [m]
0
5
10
15
20
0 5 10 15 20 25 30 35
Bz
[T]
z [m]
Ltaper= 5 [m]Ltaper=15 [m]Ltaper=25 [m]Ltaper=35 [m]
0
5
10
15
20
0 5 10 15 20 25 30 35
Bz
[T]
z [m]
Ltaper= 5 [m]Ltaper=15 [m]Ltaper=25 [m]Ltaper=35 [m]
0 5
10 15
20 25
30 35 0
0.05 0.1
0.15 0.2
0.25 0.3
0.35 0.4
0.45 0.5
0 2 4 6 8
10 12 14 16 18 20
Bz(
z,R
) [T
]
z [m]
R [m]
Bz(
z,R
) [T
]
Inverse-Cubic Taper Bz (0, zi < z < z f ) =
B1[1+ a1(z− z1)+ a2 (z− z1)
2 + a3(z− z1)3]p
a1= − B1'
pB1a2 = 3
(B1 / B2 )1/p −1
(z2 − z1)2 −
2a1z2 − z1
a3 = −2(B1 / B2 )
1/p −1(z2 − z1)
3 +a1
(z2 − z1)2
Bz (r, z) = (−1)nn∑ a0
(2n) (z)(n!)2
( r2)2n
Off-axis field approximation Br (r, z) = (−1)n+1n∑ a0
(2n+1)(z)(n+1)(n!)2
( r2)2n+1
a0(n) =
dna0dzn
=dnBz (0, z)
dzn
1.5 T 2.5 T 3.5 T
1.5 T 2.5 T 3.5 T
5
6/20/13 Hisham Sayed - MAP meeting 2013
MARS SIMULATIONS & TRANSMISSION
0.35
0.36
0.37
0.38
0.39
0.4
0.41
0.42
500 1000 1500 2000 2500 3000 3500 4000 4500
N[m
uons
]/N[p
]
Zend [m]
Bz=20 -> 1.5 T15 -> 1.5 T
15 -> 1.66 T15 -> 1.8 T
MARS1510 Simulation: Counting muons at 50 m with K.E. 80-140 MeV
Ltaper [cm]
rfinal =30 cm
Rini=7.5-10 cm
Bi=20-15 T
Hisham Sayed - MAP meeting 2013 6/20/13
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LONGITUDINAL PHASE SPACE DISTRIBUTIONS (SHORT VERSUS LONG TAPER)
Hisham Sayed - MAP meeting 2013 6/20/13
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Long adiabatic taper 40 m
Short taper 4 m
End of taper End of Decay
PHASE SPACE DISTRIBUTIONS (SHORT VERSUS LONG TAPER)
Short Taper Long Taper
T-Pz Correlations at end of decay channel Long Solenoid taper: Ø More particles Ø More dispersed (misses the buncher acceptance windows) Short Solenoid taper: more condensed distributions that fits more particles within the buncher acceptance windows
Hisham Sayed - MAP meeting 2013 6/20/13
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PHASE SPACE DISTRIBUTIONS (SHORT VERSUS LONG TAPER)
Short Taper 4 m Long Taper 40 m
T-Pz phase space at end of decay channel
Hisham Sayed - MAP meeting 2013 6/20/13
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Long Solenoid taper: Ø More particles Ø More dispersed (misses the buncher
acceptance windows)
Short Solenoid taper: Ø Higher density t-pz distribution Ø Fits more particles within the
acceptance of buncher/rotator
PHASE SPACE - SHORT VERSUS LONG TAPER
0
0.2
0.4
0.6
0.8
1
160 180 200 220 240 260 280 300
Pz [GeV/c]
T [nsec]
Bz=20-1.5 z=50 m
Ltaper=4.00 GoodLtaper=40.00 Good
Shor
t Tap
er
Long
Tap
er
Short Taper
Long Taper
T-Pz Correlations at end of decay channel of good particles
Good Particles
Green: Initial distribution of good particles which were bunched and cooled in 4D cooling channel
Hisham Sayed - MAP meeting 2013 6/20/13
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PERFORMANCE DEPENDENCE ON TIME OF FLIGHT (RF PHASE)
0
200
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1000
1200
1400
1600
1800
0 2 4 6 8 10
Meson/Proton
Time [nsec]
t=2.044e-09 sect=2.544e-09 sect=3.044e-09 sect=3.544e-09 sect=4.044e-09 sec
t=4.544e-09 sec -BSLINEt=5.044e-09 sect=5.544e-09 sect=6.044e-09 sect=6.544e-09 sec
0
0.01
0.02
0.03
0.04
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0.08
-5 0 5 10 15
MARS1015 2012OLDOLD
TOA Proton
s at z=-‐200 cm
TOA Proton
s at z=-‐75 cm
Hisham Sayed -‐ MAP meeJng 2013 6/20/13
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0
2000
4000
6000
8000
10000
12000
0 50 100 150 200 250 300 350
Muon+/proton
z [m]
TOA vs. End n1 Ltaper=8 m B=20-1.5T
TOA=5.38012e-09TOA=4.88014e-09TOA=3.88019e-09TOA=2.88023e-09TOA=1.88028e-09TOA=1.3803e-09
TOA=8.80321e-10TOA=3.80343e-10
TOA=-6.19613e-10TOA=-1.61957e-09TOA=-2.11955e-09TOA=-3.1195e-09
TOA=-4.11946e-09
2000
3000
4000
5000
6000
7000
8000
9000
0 5 10 15 20 25 30 35
Muon
Iteration
"output.all.dat" u 2Optimizing RF Phase
FRONT END PERFORMANCE
Using baseline cooling section (140 cooling cell)
Using longer cooling section (200 Cooling cell)
Hisham Sayed - MAP meeting 2013 6/20/13
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0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.1
0.11
0.12
0 5 10 15 20 25 30 35 40
Muon/proton
Taper Length [m]
Bz=20-1.5TBz=15-1.5TBz=15-2.5T
0.08
0.085
0.09
0.095
0.1
0.105
0.11
0.115
0.12
0.125
0 5 10 15 20 25 30 35 40
Muon/proton
Taper Length [m]
Bz=20-1.5TBz=15-1.5TBz=15-2.5T
~ 30%
~ 30%
High statistics tracking of Muons through the front end
FRONT END PERFORMANCE Using longer cooling section
(200 Cooling cell)
Hisham Sayed - MAP meeting 2013 6/20/13
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High statistics tracking of Muons through the front end
0 5 10 15 200.08
0.09
0.1
0.11
0.12
0.13
0.14
Taper Length [m]
Nm
uon/
Npr
oton
Bz=20−1.5TBz=20−2.0TBz=20−2.5TBz=15−1.5TBz=15−2.0TBz=15−2.5T
0.11
0.115
0.12
0.125
0.13
0.135
0.14
0 0.5 1 1.5 2 2.5 3
Muon+/proton
Proton Bunch Length [nsec]
Bz(Target)=15 TBz(Target)=20 T
0.115
0.12
0.125
0.13
0.135
0.14
0.145
0.15
0.155
0.16
1.5 2 2.5 3 3.5
Muon+/proton
Constant Bz [T]
MUON YIELD VERSUS END FIELD & BUNCH LENGTH
Bunch length=0 nsec
Muon yield versus end field Muon yield versus Proton Bunch Length
Performance of FE as function of Constant solenoid filed in Decay Channel – Buncher – Rotator (matched to +/- 2.8 T ionization cooling channel)
~ 3% loss per 1 nsec increase in bunch length
Baseline
Bz(Target)=20 T 20% for every 1 T incerease in
constant field
Hisham Sayed - MAP meeting 2013 6/20/13
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NEW SHORT TARGET CAPTURE REALISTIC MAGNET (WEGGEL)
6/18/13
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Muon Target Capture Magnet Short Taper length =7 m- B=20-1.5 T
−5 0 5 10 15 20 25−2
−1.5
−1
−0.5
0
0.5
1
1.5
2
Z [m]
Y [m
] Bz=1.5T
Bz=20 T
On axis field [scale /20 T]
Target Magnets
Decay channel Triplet
Taper Magnets
Hisham Sayed BNL −5 0 5 10 15 20 25−3
−2
−1
0
1
2
3
Z [m]
Y [m
] Bz=2.5T
Bz=20 T
On axis field [scale /20 T]
Target Magnets
Decay channel Triplet
Taper Magnets
Muon Target Capture Magnet Short Taper length =5 m- B=20-2.5 T
0 5 10 15 20 25Z [m] 0 0.05
0.1 0.15
0.2 0.25
0.3
R [m] 0 2 4 6 8
10 12 14 16 18 20
z [T] 0 2 4 6 8 10 12 14 16 18 20
NEW SHORT TARGET CAPTURE MAGNET (WEGGEL)
6/18/13
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Muon Target Short Taper Magnet taper length =7 m- B=20-1.5 & 2.5 T
Target SC Magnets Field Map calculated from realistic coils
Bz [T]
Hisham Sayed BNL
Engineering (V. Grave) IDS120_20-1.5T7m2+5 Cryo 1
NEW DECAY CHANNEL REALISTIC MAGNET (WEGGEL)
6/19/13
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Hisham Sayed BNL
0 2 4 6 8 101.3
1.35
1.4
1.45
1.5
1.55
1.6
Magnet Length [m] Inner R [m] Outer R [m] J [A/mm2]
1 0.19 0.6 0.68 47.18
2 3.8 0.6 0.63 40.00
3 0.19 0.6 0.68 47.18
IDS120L20-1.5T 7m
Ø The pions produced in the target decay to muons in a Decay Channel (50 m) Ø Three superconducting coils (5-m-long ) Bz(r=0) ~ 1.5 or 2.5 T solenoid field. Ø Suppress stop bands in the momentum transmission.
Axial-field profile of two Decay-Channel modules
7 m 5 m
REALISTIC COIL BASED DECAY CHANNEL SOLENOID STOP BAND STUDY
6/21/13
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Suppression of stop bands in the Decay Channel: Tracking muons through decay channel 10 cells (50 m) optimize magnet design for best performance
Transmission: Constant 1.5 Solenoid Field %67 IDS120L20to1.5T7m %62 Modified IDS120L20to1.5T7m %66
Hisham Sayed BNL
0
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500
600
700
800
900
1000
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55
N
P [GeV/c]
Modified 1.5 T Channel v021.5 T Channel v02
IDS120L20to1.5T7m IDS120L20to1.5T7m
0
100
200
300
400
500
600
700
800
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55
Muon
Ptot [GeV/c]
1.5 T constant solenoid fieldField generated from Coils
Optimization
CONCLUSION & SUMMARY
Hisham Sayed -‐ MAP meeJng 2013 6/20/13
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1- Target Solenoid parameters that affect the particle Capture & Transmission at target or after cooling Initial peak Field – Taper length – End Field 2- Impact: Short taper preserves the longitudinal phase-space à muons can be captured efficiently in the buncher-phase rotation sections and more muons at the end of cooling. The maximum yield requires taper length of 7-5 m for all cases (20-15T) (1.5-3.5T) for any bunch length. 3- Final constant end field increases the yield by 20% for every 1 T increase in the field beyond the 1.5 T baseline 4- Initial proton bunch length influence the muon/proton yield at the end of the cooling channel ~ 3% reduction per 1 nsec increase in bunch length. 5- Realistic Coil design.
