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OPTIMIZED SOLENOID BASED CAPTURE MECHANISM FOR A MUON COLLIDER/NEUTRINO FACTORY TARGET SYSTEM
HISHAM KAMAL SAYED Physics Department
BROOKHAVEN NATIONAL LABORATORY
HIGGS FACTORY UCLA MARCH 22 2013
LAYOUT
1-‐ Introducing Muon Collider Target & Front END 3-‐ Capture Solenoid Field Study: QuesNons that needs answers
u What are the target Solenoid parameters that affect the parNcle Capture & Transmission at target or aTer cooling
u Can/How Capture Solenoid change the quanNty & quality of captured parNcles ?! u Does the Nme of arrival affect the efficiency of the capturing mechanism? u Does the proton bunch length influence the muon/proton yield at the end of the cooling channel ?
4-‐ Muon yield at end of decay channel 5-‐ Muon yield at end of cooling channel 6-‐ Taper scan 7-‐ Time of arrival dependence & Nme scan 8-‐ Results of taper & TOA opNmizaNon
Hisham Sayed -‐ Higgs factory UCLA 13/22/13
2
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 -‐ Higgs factory UCLA 13/22/13
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TARGET SYSTEM CURRENT BASELINE DESIGN
Ø ProducNon of 1014 µ/s from 1015 p/s (≈ 4 MW proton beam)
Ø Capturing low energy π's Ø Solenoid coils can be some distance from proton beam.
Ø ≥ 10-‐year life against radiaNon damage at 4 MW. Ø Proton beam readily Nlted with respect to magneNc
axis. Ø ⇒ Beam dump (mercury pool) out of the way of
secondary π's and µ's. Ø Shielding of the superconducNng magnets from
radiaNon is a major issue. Ø Magnet stored energy ~ 3 GJ
SC magnets
ResisNve magnets
Proton beam and Mercury jet
Tungsten beads
Mercury collecNon pool With splash miNgator
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 θTarget=0.137 rad Ø RTarget=0.404 cm
Ø Proton Beam Ø E=8 GeV Ø θBeam=0.117 rad Ø σx=σy=0.1212 cm (Gaussian DistribuNon)
Ø Solenoid Field Ø IDS120h à 20 T peak field at target posiNon (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 ProducNon: Muons within energy KE cut 40-‐180 MeV end of decay channel
Ø Nμ+π+κ/NP=0.3-‐0.4 Hisham Sayed -‐ Higgs factory UCLA 13/22/13
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TAPERED TARGET SOLENOID
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 approximaNon 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
MARS SIMULATIONS & TRANSMISSION
0
0.1
0.2
0.3
0.4
0.5
0.6
0 50 100 150 200 250 300
N [
Muon
s]
Z [m]
Ltaper= 4.00 m n1Ltaper= 12.00 m n1Ltaper= 24.00 m n1Ltaper= 40.00 m n1Ltaper= 4.00 m n0
Ltaper= 12.00 m n0Ltaper= 24.00 m n0Ltaper= 40.00 m n0
Ltaper= 4.00 m NLtaper= 12.00 m NLtaper= 24.00 m NLtaper= 40.00 m N
Nmuons{Good}
Nmuons{Pz cut}
Nmuons{All cuts}
Good parNcles condiNons/cuts Ø Survived the buncher-‐phase rotator and cooling
secNons Ø AcceleraNon acceptance cuts
Ø 0.1 <Pz< 0.3 GeV Ø Transverse cut R < 0.03 m Ø Longitudinal cut < 0.015 m
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
MARS simulaNon results CounNng muons at 50 m with K.E. 80-‐140 MeV MARS-‐ICOOL simulaNon results
CounNng muons at various z
Ltaper [cm]
rfinal=30 cm
Rini=7.5-‐10 cm
Bi=20-‐15 T
Hisham Sayed -‐ Higgs factory UCLA 13/22/13
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PHASE SPACE DISTRIBUTIONS (SHORT VERSUS LONG TAPER)
0
0.0005
0.001
0.0015
0.002
0.0025
0.003
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45
Meson/Proton
R [m]
Bz=20-1.5 z=50
Ltaper=4.00Ltaper=40.00
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0 0.5 1 1.5 2 2.5 3
Meson/Proton
Pz [GeV/c]
Bz=20-1.5 z=50 m
Ltaper=4.00 Ltaper=40.00
0
0.001
0.002
0.003
0.004
0.005
0.006
0.007
0.008
0.009
0 0.05 0.1 0.15 0.2 0.25
Meson/Proton
Pt [GeV/c]
Bz=20-1.5 z=50
Ltaper=4.00 Ltaper=40.00
0
0.0005
0.001
0.0015
0.002
0.0025
0.003
0.0035
0.004
0 1 2 3 4 5 6 7
Meson/Proton
Ptotal [GeV/c]
Bz=20-1.5 z=50 m
Ltaper=4.00 Ltaper=40.00
π Good μ
All μ
Good μ
All μ
Good μ
All μ
Good μ
All μ
No difference between short & long solenoid taper produced parNcles Hisham Sayed -‐ Higgs factory UCLA 13/22/13
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PHASE SPACE DISTRIBUTIONS (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
Short T
aper
Long Taper
Short Taper
Long Taper
T-‐Pz CorrelaNons at end of decay channel
Good ParNcles
Long Solenoid taper: Ø More parNcles Ø More dispersed (misses the buncher
acceptance windows) Short Solenoid taper: more condensed distribuNons that fits more parNcles within the acceptance window)
Hisham Sayed -‐ Higgs factory UCLA 13/22/13
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PERFORMANCE DEPENDENCE ON TIME OF ARRIVAL
0
0.02
0.04
0.06
0.08
0.1
0.12
0 50 100 150 200 250 300
Muon+/proton
Z [m]
Bz=15-1.5T Ltaper= 5.000
DTOA=2.044e-09 DTOA=4.044e-09 DTOA=6.544e-09
DTOA=1.1544e-08
0
0.02
0.04
0.06
0.08
0.1
0.12
0 50 100 150 200 250 300
Muon+/proton
Z [m]
Bz=20-1.5T Ltaper= 5.000
DTOA=2.044e-09 DTOA=4.044e-09 DTOA=6.544e-09
DTOA=1.1544e-08
0
200
400
600
800
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
0.05
0.06
0.07
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 -‐ Higgs factory UCLA 13/22/13
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MORE COOLING ?!
0
2000
4000
6000
8000
10000
12000
0 50 100 150 200 250 300 350
Muon+/proton
z [m]
Ltaper vs. n1 B=20-1.5T
TOA=8.80321e-10 Ltaper=2.00TOA=3.80343e-10 Ltaper=4.00TOA=8.80321e-10 Ltaper=6.00TOA=8.80321e-10 Ltaper=8.00
TOA=8.80321e-10 Ltaper=12.00TOA=8.80321e-10 Ltaper=20.00
0
2000
4000
6000
8000
10000
12000
0 50 100 150 200 250 300 350Muon+/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
Baseline cooling end 140 cell (z=265 m)
For every taper length opNmized TOA For 8 m taper length TOA scan
Hisham Sayed -‐ Higgs factory UCLA 13/22/13
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TIME & TAPER LENGTH SCAN
0.01
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]
Max n1 voer z
Bz=20->1.5TBz=15->1.5TBz=15->2.0TBz=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
z [m]
Ltaper vs. n1
B=20-1.5TB=15-1.5TB=15-2.0TB=15-2.5T
Using baseline cooling secNon (140 cooling cell)
Using longer cooling secNon (200 Cooling cell)
Hisham Sayed -‐ Higgs factory UCLA 13/22/13
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TIME & TAPER LENGTH SCAN
-5
-4
-3
-2
-1
0
1
2
0 5 10 15 20 25 30 35 40
Time of Arrival [nsec]
Target Solenoid Taper Length [m]
B=20-1.5TB=15-1.5TB=15-2.0TB=15-2.5T
TOA for opNmum throughput at end of cooling for each capture solenoid case
Hisham Sayed -‐ Higgs factory UCLA 13/22/13
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OPTIMIZED MUON PRODUCTION AT END OF FRONTEND (BPEAK=20-‐15 T)
0.04
0.06
0.08
0.1
0.12
0.14
0 2 4 6 8 10
Nmoun/Nproton
Taper Length [m]
Pancake Proton Beam Bzi=20 T
Bz=20-1.5TBz=20-2.0TBz=20-2.5TBz=20-3.5T
Baseline
Hisham Sayed -‐ Higgs factory UCLA 13/22/13
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>%20
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0 2 4 6 8 10
Nmoun/Nproton
Taper Length [m]
Pancake Proton Beam Bzi=15 T
Bz=15-1.5TBz=15-2.0TBz=15-2.5TBz=15-3.5T
MUON YIELD VERSUS END FIELD & BUNCH LENGTH
0.11
0.115
0.12
0.125
0.13
0.135
0.14
0 0.5 1 1.5 2 2.5 3 3.5 4
Nmoun/Nproton
Bunch Length [nsec]
Production - Proton Bunch Length
Bi=15 T
Bi=20 T
Bunch length=0 nsec
0.11
0.115
0.12
0.125
0.13
0.135
0.14
1 1.5 2 2.5 3 3.5 4
Nmoun/Nproton
B end [T]
Production -Final Solenoid Field
Bi=15TBi=20T
Muon yield versus end field Muon yield versus Proton Bunch Length
Losses at B=3.5T might be due to match to the cooling secNon
2.5% loss per 1 nsec increase in bunch length
Baseline Baseline
20% increase
5% 10%
Hisham Sayed -‐ Higgs factory UCLA 13/22/13
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1-‐ Target Solenoid parameters that affect the parNcle Capture & Transmission at target or aTer cooling IniNal peak Field – Taper length – End Field 2-‐ Can Capture Solenoid change the quanNty & quality of captured parNcles ?! yes & yes a-‐ QuanNty: More muons captured with adiabaNc long taper than short taper. b-‐ Quality: Produce be�er quality muons that can be captured efficiently in the buncher-‐phase rotaNon secNons. 3-‐ How the capture solenoid field parameters influence the muon yield a-‐ Peak field (changes quanNty) b-‐ Taper length (quality) c-‐ Final constant end field (quanNty) 4-‐ Does the Nme of arrival affect the efficiency of the capturing mechanism? Yes. Needs to be included in the opNmizaNn of the FE 5-‐ Does the proton bunch length influence the muon/proton yield at the end of the cooling channel ? How? Yes, %2.5 reducNon per 1 nsec increase in bunch length.
CONCLUSION & SUMMARY
Hisham Sayed -‐ Higgs factory UCLA 13/22/13
15
CONCLUSION & SUMMARY
Ø The maximum yield requires taper length of 4-‐5 m for all cases (20-‐15T)
(1.5-‐3.5T) for any bunch length.
Ø Longer cooling channel is required to reach maximum cooling.
Ø Higher end field à more muon yield
Ø Longer bunch à Less yield we loos about 2.5% per 1 nsec increase in bunch
length.
Hisham Sayed -‐ Higgs factory UCLA 13/22/13
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