1 meson production simulations x. ding, d. b. cline ucla h. kirk, j. s. berg bnl n u f a c t 0 9...
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1
Meson Production Simulations
X. Ding, D. B. Cline UCLA
H. Kirk, J. S. Berg BNL
N u F a c t 0 9
11th International Workshop onNeutrino Factories, Superbeams and Beta Beams
July 20-25, 2009 — IlT — Chicago
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Outline
• Mercury Target Geometry and Optimized Target Parameters (Beam below Mercury Jet)
• Beam Initial Position, Beam/Jet Crossing Angle and Beam Path Length inside the Hg Jet (Beam below Mercury Jet)
• Multiple Proton Beam Entry Directions (Beam around Mercury Jet)
• Meson Production • Summary
3
Neutrino Factory Target Concept
SC Coils
Cu Coils
Fe Plug
Hg Containment
Hg Pool
4
Mercury Target Geometry
1. The proton beam is below the Hg jet at z=-75cm.2. Count all the pions and muons of positives and negatives that cross the transverse plane at z=50m.3. For this analysis we select all pions and muons with
40MeV<KE<180MeV.
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Optimized Target Parameters at z=-75cm
1. Beam and Jet cross only at z=-37.5cm. Beam angles also vary at different z. So the crossing angle at z=-75cm actually means the angle between beam moving direction and jet.
2. Previous Baseline: radius of 0.5cm,beam angle of 67mrad and beam/jet crossing angle of 33mrad.
0.3
0.35
0.4
0.45
0.5
0.55
0.6
0.65
0 10 20 30 40 50 60 70 80 90 100
TargetRadius,cm
Proton Kinetic Energy, GeV
0
20
40
60
80
100
120
140
0 10 20 30 40 50 60 70 80 90 100
BeamAngle,mrad
Proton Kinetic Energy, GeV
-5
0
5
10
15
20
25
30
0 10 20 30 40 50 60 70 80 90 100
CrossingAngle,mrad
Proton Kinetic Energy, GeV
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Meson Production w/wt Optimization
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0 10 20 30 40 50 60 70 80 90 100
Mesons/protons/GeV
Proton Kinetic Energy, GeV
without optimizationwith optimization
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Required Beam Initial Position at z=-75cm to Achieve x=y=0 at z=-37.5cm)
0 20 40 60 80 100
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Initi
al p
ositi
on o
f be
am (
x0),
cm
Proton Kinetic Energy, GeV
Initial position (x0) vz. KE
0 20 40 60 80 1002.6
2.8
3.0
3.2
3.4
3.6
3.8
4.0
4.2
4.4
4.6
Initi
al p
ositi
on (
y0),
cm
Proton Kinetic Energy, GeV
Initial position (y0) vz. KE
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Effect of Different Beam Initial Position
0.319
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Beam/Jet Crossing Angle at z=-75cm and z=-37.5cm
8GeV, 18.55mrad at z=-75cm and 27.05mrad at z=-37.5cm
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Beam Path Length inside the Mercury Jet
Nuclear interaction length for Hg is 14.58cm
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Multiple Proton Beam Entry Directions 8GeV, Roll angle(Φ): Telling us what side of the jet the
beam is on. (below: Φ=π, up: Φ=0, left: Φ= π/2,
right: Φ=3π/2) Clearance: Telling us the extent of proton beam
away from the Hg jet at z=-75cm.
xj=0, yj=3.64cm. (x0, y0) is beam initial position.
jbjj rcmrmrad 3.0,4.0,68.96
b
jjj ryyxxC
2
02
0
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Multiple Proton Beam Entry DirectionsThe Required Beam Position at z=-75cm to Keep Same Crossing Angle and 240 Roll Angle Apart at z=-37.5cm
p0
p4
p8
p12 jet(0, 3.64)
y
x
Previous Incident Beam at z=-75cm for optimization
p1p2
p3
p5
p6p7
p9
p10
p11
p13
p14
4.3% higher in meson production at p11 than at p6
=00
=960
=2640
=1920
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Multiple Proton Beam Entry Directionsx-y plot of proton relative to jet at different z
-1.6 -1.4 -1.2 -1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
z=-37.5cm
p14, z=-75cm
p11, z=-75cm
p8, z=-75cm
p5, z=-75cm
p2, z=-75cm
Vary z from -75cm to -37.5cm in steps of 2.5cmY
(pro
ton)
-Y(j
et),
cm
X(proton)-X(jet), cm
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Multiple Proton Beam Entry Directions
-50 0 50 100 150 200 250 300 350 4000
10
20
30
40
50
60
70
80
90
100
110
120
130A
ngle
, mra
d
Roll Angle, degree
Beam/Jet Crossing Angle (z=-37.5cm) Beam/Jet Crossing Angle (z=-75cm) Beam Angle to Solenoid Axis (z=-75cm) Hg Jet Angle to Solenoid Axis
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Multiple Proton Beam Entry DirectionsClearance at z=-75cm for Same Crossing Angle and
240 Roll Angle apart at z=-37.5cm
p0
p4
p6
p11
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Multiple Proton Beam Entry DirectionsMeson 40MeV<KE<180 MeV at 50m for Same Crossing
Angle and 240 Roll Angle apart at z=-37.5cm
p11
p6
p4
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Increasing Clearance of p4
26 28 30 32 34 36 38 40 42 441
2
3
4
5
6
7
Cle
aran
ce
Crossing angle of beam/jet, mrad
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Normalized Meson Production(beam below jet)
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Normalized Mesons at 50m(beam below jet)
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Summary• Target parameters of incident beam below Hg target and KE from 2 to 100GeV are optimized.• Beam angles and beam/jet crossing angles vary at low KE due to magnet field. • The beam path length inside the jet is less than 2 times of the Hg interaction length at low KE.• Layouts of multiple proton beam entry directions relative to the Hg jet at z=-75cm are determined to achieve the same crossing angle at z=-37.5cm. • There is about 4% increase in meson production at p11 compared to p6.