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Proton Delivery to Target
Keith Gollwitzer
Accelerator Division
Fermilab
MAP 2012 Winter Meeting March 7, 2012
Gollwitzer -- Proton Delivery to Target 2
Outline• Conceptual delivery of beam to target• Effects of target solenoids on proton
beam(s)– Cross check with some work on target
optimization– Further investigations
• Parallel work done by Eliana Gianfelice-Wendt and myself– Tracking, Matrices, Spreadsheets....
March 7, 2012
Gollwitzer -- Proton Delivery to Target 3
Neutrino Factory Delivery Concept
• Task Force concept is to operate the pulsed linac at 15 Hz.
• Accumulate 9 or 12 bunches• Transfer 3 bunches to Compressor• Rotate and then extract bunches with
correct bunch spacing of 120 μs
– Effectively 45 or 60 Hz
March 7, 2012
Gollwitzer -- Proton Delivery to Target 4
Muon Collider Delivery Concept
• Task Force concept is to operate the pulsed linac at 15 Hz.
• Accumulate 4 to 8 bunches• Transfer all bunches to Compressor• Rotate and then extract bunches in single
turn• Each bunch is sent on a different path
(trombone) so that they all arrive at the target instantaneously
March 7, 2012
5Gollwitzer -- Proton Delivery to Target
Muon Collider Trombone
March 7, 2012
Gollwitzer -- Proton Delivery to Target 6
Single Beam to Target
• Want to know how solenoid will affect proton beam line
• Start from work done on optimizing target– Ding, Berg, Cline and Kirk, “Optimization of a
mercury jet target for a neutrino factory or a muon collider”, PRST-AB 14. 111002 (2011)
– Uses 2011 target station concept and varies many parameters to optimize the number of usable muons (uses 8 GeV proton beam)
March 7, 2012
7Gollwitzer -- Proton Delivery to Target
PRST-AB Optimization
March 7, 2012
Jet/Solenoid angle: 96.7 mradJet/Proton Beam angle: 27 mrad at IPJet radius: 0.4cmProton Beam Energy: 8 GeV
Proton Beam is GaussianProton Beam Radius (rms) is 30% of jet radiusSolenoid Field is 20 T in interaction regionJet is in y-z plane
Gollwitzer -- Proton Delivery to Target 8
PRST-AB Optimization
• Initial optimization is with beam coming from below– Roll angle of 180o
• Investigate proton beam azimuthal approach– Propagate proton beam back to -75 cm– Helical paths for beam to always intersect at
(0 cm, 0 cm, -37.5 cm)– Investigated 15 paths with different roll angles
into the jet
March 7, 2012
9Gollwitzer -- Proton Delivery to Target
Need Solenoid Information
March 7, 2012
“The Target System Baseline”, Kirk & McDonald (Feb 4, 2011)
Proton Beam in Solenoid
field
10Gollwitzer -- Proton Delivery to Target
Solenoids Layout
March 7, 2012
z (cm)
r (cm)
11Gollwitzer -- Proton Delivery to Target
Field on axis
March 7, 2012
z (cm)
B_z (T)
12Gollwitzer -- Proton Delivery to Target
Radial field
March 7, 2012 z (cm)
B_r (
T)
r = 7 cm
From Ding
13Gollwitzer -- Proton Delivery to Target
Reproducing PRST-AB Beam Paths -75 cm to -37.5cm
March 7, 2012
14Gollwitzer -- Proton Delivery to Target
Beam Distance from Jet
March 7, 2012
Clea
ranc
e is
in b
eam
sig
mas
at -
75 c
m
15Gollwitzer -- Proton Delivery to Target
X & Y vs Z
March 7, 2012
16Gollwitzer -- Proton Delivery to Target
X vs Y
March 7, 2012
8m to IP
0.5m to IP
Gollwitzer -- Proton Delivery to Target 17
Single Beam Path• Optimization of
muons per roll angle results in roll of 264o
• Roll of 95.4o results in hitting jet twiceZ = -123 and -37.5 cm
March 7, 2012
Gollwitzer -- Proton Delivery to Target 18
Beam Size
Z [m] σrms [cm]
-3 1.06
-4 1.45
-5 1.85
-6 2.25
-7 2.65
-8 3.05
• At IP, σrms = 0.12 cm
• Optimization shows that β* ≥ 0.3 m – Requires ε ≤ 4.8 μm
• For β* = 0.3 m
March 7, 2012
Gollwitzer -- Proton Delivery to Target 19
Multiple Beam Paths• Start with four beam paths separated by
roll angle of 90o
• Want to be away from path which could hit jet (or apparatus)– Want to be 45o from this path
• Will investigate the distance between beam centers
• Beam Paths’ Rolls:– 50.4o, 140.4o, 230.4o and 320.4o
March 7, 2012
20Gollwitzer -- Proton Delivery to Target
Four Beam Paths
March 7, 2012
8m to IP 0.5m to IP
Distance to jet 0.5m to IP
21Gollwitzer -- Proton Delivery to Target
X vs Y at Different Z
March 7, 2012
22Gollwitzer -- Proton Delivery to Target
X vs Y at Different Z
March 7, 2012
-3m -4m -5m
-6m -7m -8m
23Gollwitzer -- Proton Delivery to Target
Distance Between Beam Paths
March 7, 2012
Distance from “opposite” paths
Distance from nearest paths
σrms
Gollwitzer -- Proton Delivery to Target 24
Summary
March 7, 2012
Extras
March 7, 2012 Gollwitzer -- Proton Delivery to Target 25