HINS ProtonSource/LEBT Beam Measurement Meeting on HINS Beam Dynamics and Diagnostics March 13, 2009...
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Transcript of HINS ProtonSource/LEBT Beam Measurement Meeting on HINS Beam Dynamics and Diagnostics March 13, 2009...
HINS ProtonSource/LEBT Beam Measurement
Meeting on HINS Beam Dynamics and Diagnostics
March 13, 2009
Salah Chaurize
Vic Scarpine
Wai-Ming Tam
Content
• Layout of HINS proton source/LEBT
• Beam profile measurement using wire scanner
• Steering capability of the trim dipole magnets
• Beam rotation by focusing solenoid
Pictures of LEBT and Wire Scanner
Proton Source Solenoid Wire
Scanner
Beam Energy = 48 keV
Beam Current = 8 mA
Name Range [Amp] [Gauss]
US Upstream Solenoid 410 – 490 3800 – 4600
DS Download Solenoid 450 – 570 4200 – 5300
UH Upstream Horizontal Trim 0 – 3 0 – 100
UV Upstream Vertical Trim 0 – 3 0 – 100
DH Downstream Horizontal Trim 0 – 3 0 – 100
DV Downstream Vertical Trim 0 – 3 0 – 100
Layout of LEBT
Wire Scanner
US DSUH, UV DH, DV
Proton
17 cm
52 cm 22.4 cm
17 cm
kpipexagxag ),,(),,( 02220111
backgroundconstant k
16.5cm radius pipe
)(1
2
)(exp),,(
22
2
20
0
r
xrr
pipe
xxaxag
Expression used for fitting:
where
A Typical Fit
Proton Other species
A Typical Wire Scan
For a typical fit, standard deviation for is about 2%.
Beam Pipe
Other species fill out the whole beam pipe.
Horizontal Beam Width
The strength of the upstream solenoid has little effect on beam size.
The size of the beam waist is measured to be ~0.7 mm.
Vertical Beam Width
The strength of the upstream solenoid has little effect on beam size.
The size of the beam waist is measured to be ~0.6 mm.
Asymmetric Beam
The beam is asymmetric.
Beam asymmetry can be due to misalignment in beamline and/or possibly from the proton source itself.
Comparison to TRACK Simulation
Input Beam for TRACK:
ε(n,rms) = 0.233 πmm-mrad
α = -1.82
β = 0.331 mm/mrad
US = 380 Amps
Current = 8 mAEnergy = 50 keV
Wire Scanner
West
Up
EastDown
Trim Dipole Steering
Trim dipoles at 100 Gauss.
All possible combinations of trim setting fall inside the diamond.
18 mm
18 mm
55o
Steering effect is rotated by the downstream solenoid.
Beam Rotation by Solenoid
Azimuthal Kick
Paper by K.T. McDonald
Solenoid
Azimuthal Kick
mc
LeB
p
eBL
effm
h
2
1
2
12
1
Angle of rotation thru solenoid
Leff
x̂
Center of Solenoid
Azimuthal Kick
Helical Path
Uniform Field
Beam Rotation by Solenoid
DS = 450 to 570 Amps
Exact location of beam needed to be analyzed.
Rotation of beam as a function of solenoid field matches well with calculations.
mc
LeB
p
eBL effm
h
2
1
2
1
2
1
Conclusion
• Beam waist at wire scanner rms ~ 0.7 mm
• Beam is asymmetric. It can possibly be due to misalignment.
• Trim dipoles steer beam +/- 9 mm both planes.
• Beam rotation due to solenoid agrees with model. Model can possibly be used to determine solenoid misalignment.
8.1 cm
Vanes of RFQ
Wire Scanner
14 cm
Downstream Solenoid
5.9 cm
Distance Between WS and RFQ
There is a known distance between the wire scanner and the vanes of the RFQ.
US = 440 amp
DS = 510 amp
Uni-Polar Steering Dipole
DV (Down)
DH (East)
UV (Up)
UH (West)
DV
DH
UVUH
UH
UV
DV
DH
Symmetric
Uni-Polar Steering Dipole
Downstream trims give more steering.
DS = 450 to 570 Amps
US = 410 to 490 Amps
Vertical Beam Width