BEABP jswiniarcernch Linac4 Linac first stage of accelerator complex Linac2 50Mev Linac225 years of technological advanceLINAC4 Linac4 160MeV high duty cycle for possible future high intensity facility ID: 778204
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Slide1
DTL Acceptance studies
Jerzy ŚwiniarskiBE-ABPjswiniar@cern.ch
Slide2Linac4
Linac – first stage of accelerator complexLinac2 – 50MevLinac2+25 years of technological advance=LINAC4Linac4 – 160MeV + high duty cycle for possible future high intensity facility
CCDTL
PIMS
3MeV
50MeV
102MeV
160MeV
CHOPPER
RFQ
H-
3MeV
45keV
DTL
Slide3DTL
352.2MhzTank1 – 12MeVTank2 – 30MeVTank3 – 50MeVAcceptance
Error Studies
Slide4Name
Tank 1Tank 2Tank 3
FFDDFFDD
FFDD
FFDD
FDFD
FFDD
FDFD
FDFD
FDFD13FDFDFDFD
FDFD
Slide5Acceptance
Area in phase spaceParticles survived and were properly acceleratedUsually – at the injection pointMy simulations – in the half of 1st quadrupoleScanning“BigBeam
”
Slide6ScanningProbe beam – small in all planes
Approximation of “point” in phase spaceSpace charge turned offInitial position and divergence shift – position
in phase
space
Transmissions
≈0% or ≈100%
Slide7„Big beam”
Beam big in one plane – other planes do not affect calculations
Uniform distribution of
particles
Area
covers
all the
acceptanceSpace charge turned offObserving lost
particlesALL – lost = survivors = acceptance
Slide8Results
Scanning – XX’
Big
Beam
– XX’
Slide9Results
Scanning – YY’
Big
Beam
– YY’
Slide10Results
XX'
SCANNING
BIGBEAM
Δ[%]
FFDD
53.428
[
mm*mRad
]
53.048[mm*mRad
]0.711
FDFD
54.404[mm*mRad]
54.454
[mm*mRad]
-0.092
FDFD13
60.030[
mm*mRad]
59.922
[mm*mrad
]0.179
Both
method
s give very simillar
results
Big
Beam
–
definitely
faster
+
ability
to
observe
each
tank
Big
Beam
–
simulation-only
method
Real
measurements
with
pencilbeam
and
steering
magnets
YY'
SCANNING
BIGBEAM
Δ[%]
FFDD
50.555
[
mm*mRad
]
51.421
[
mm*mRad
]
-1.714
FDFD
52.152
[
mm*mRad
]
53.010
[
mm*mRad
]
-1.645
FDFD13
58.410
[
mm*mRad
]
58.983
[
mm*mRad
]
-0.980
Slide11Real measurements
Dump not necesarry for measurementsFirst magnet changes position
Second magnet right before
entrance
of DTL
changes
divergence
Slide12Longitudinal acceptance
Only with scanningThe same idea like in
transverse planes
Shifting
in
phase and energyOutput
filter in phase and energy - -0.22-0.35Rad, 45-55MeVOnly properly
accelerated particlesAcademic method
only
Slide13Errors Studies
Structure’s sensitivity to production and assembly errors – misalignments of
quadrupolesStatistical simulations
using
big
beam
methodRandom misalignment
errors in each runGaussian distribution (σ
=0.01), 3000 simulationsIndependent misalignments in x and y
Simulations made twice – checking
acceptance of each plane
Slide14Errors Studies
Result – CDF (cumulative distribution function)Different acceptances of
each structureNormalization
with
different
factors
Plane\StructureFDFD
FFDDX-X’9.341
9.653
Y-Y’9.3414
9.6154
Slide15FDFD
slightly
more sensitive
Bigger
acceptance
in FDFDLines
crossing – bigger acceptances more probable
in FDFDWorst
case:
FDFDFFDD
X-X’49.5%
64.9%
Y-Y’52.2%
60.2%
Slide16Summary:
Both methods can be used for transverse acceptance – in
future probably
also
for
longitudinal
FDFD
more sensitive to misalignments
, however with bigger acceptance
Slide17Thank You
for Your attention