Beam Transfer Lines for the Spallation Neutron Source
Beam Transfer Lines for the Spallation Neutron Source
D. Raparia, Y. Y. Lee, W. T. Weng and J. Wei
D. Raparia, Brookhaven
Y. Y. Lee,National
W. T.Laboratory
Weng and J. Wei
P. O. Box
5000, Upton,
NY Laboratory
11793, Upton, USA
Brookhaven
National
Box 5000,
Upton,Source
NY 11793,
USA to have low beam losses for hand on
Abstract. Beam transfer lines forP.
theO.Spallation
Neutron
(SNS)Upton,
are designed
maintenance
while
satisfying
the
facility
footprint
requirements.
There
are
two
main
transfer
lines, losses
High Energy
Abstract. Beam transfer lines for the Spallation Neutron Source (SNS) are designedbeam
to have
low beam
for handBeam
on
Transport
(HEBT)
whichthe
connect
conducting
linac toThere
the accumulator
andtransfer
Ring tolines,
Target
Beam
transport
maintenance
while line
satisfying
facilitysuper
footprint
requirements.
are two mainring
beam
High
Energy
Beam
(RTBT)
which
transfers
beamconnect
from accumulator
ring tolinac
the target.
HEBT line not
transfer
the beam
from
linac to ring but
Transport
(HEBT)
line which
super conducting
to the accumulator
ringonly
and Ring
to Target
Beam
transport
also
prepare
beam
for ring
injection,
correct the ring
energy
jitter
fromHEBT
the linac,
energy
for the
(RTBT)
which
transfers
beam
from accumulator
to the
target.
line provide
not only required
transfer the
beamspread
from linac
to ring but
injection,
clean
thefor
transverse
and longitudinal
halo particles
fromthethe
beam,
determine
theenergy
linac beam
quality,
also prepare
beam
ring injection,
correct the energy
jitter from
linac,
provide
required
spread
for theand
ringprovide the
protection
to thethe
accumulator
RTBT line halo
transport
the beam
from
ringdetermine
to target while
fulfilling
the target
injection, clean
transverse ring.
and longitudinal
particles
from the
beam,
the linac
beam quality,
andrequirements
provide the of
beam
size, to
maximum
current density,
beam
onthe
thebeam
targetfrom
in case
kickerthe
failure,
protect theoftarget
protection
the accumulator
ring. RTBT
linemoment
transport
ring of
to ring
targetextraction
while fulfilling
targetand
requirements
beamthe
size,
maximum
current density, beam moment on the target in case of ring extraction kicker failure, and protect the target
from
ring
fault conditions.
from the ring fault conditions.
INTRODUCTION
INTRODUCTION
The 1.4 MW Spallation Neutron Source (SNS) is
The
1.4 MW Spallation
Neutron
SourceLaboratory,
(SNS) is
under
construction
in Oak Ridge
National
under
construction
in
Oak
Ridge
National
Laboratory,
order of magnitude higher power than any other
order ofmachines.
magnitudeThe
higher
power
thanis any
other
existing
whole
facility
design
for
existing machines. The whole facility is design for
low un-controlled
beam losses for hand on
low un-controlled
beam losses for hand on
maintenance. The SNS[1] consists l.OGeV super
maintenance. The SNS[1] consists 1.0GeV super
conducting Linac[2] and an accumulator ring[3] and
conducting Linac[2] and an accumulator ring[3] and
two
High Energy
Energy Beam
BeamTransfer
Transfer
two main
main transfer
transfer lines.
lines. High
(HEBT)
line[4]
connects
super
conducting
Linac
the
(HEBT) line[4] connects super conducting Linac totothe
accumulator
ring
and
Ring
to
Target
Beam
Transfer
accumulator ring and Ring to Target Beam Transfer
(RTBT)
accumulator ting
ting toto the
the
(RTBT) line[5]
line[5] connects
connects accumulator
target.
These
lines
are
carefully
designed
to
have
low
target. These lines are carefully designed to have low
uncontrolled
with several
several new
newfeatures
featuresinin
uncontrolled beam
beam losses
losses with
these
corrector and
and spreader
spreadercavities,
cavities,
these lines
lines like
like energy
energy corrector
collimators
collimators etc.
etc.
FIGURE 1.
1. SNS
SNS transfer
FIGURE
transfer lines
lines and
andring
ringlayout.
layout.
HIGH ENERGY BEAM TRANSFER
HIGH
ENERGY BEAM TRANSFER
LINE
LINE
-
HEBT is about 180 meter long and carry H ion with
HEBT
is aboutcurrent
180 meter
longinand
carry
ion with
peak average
of 38 mA
1 ms
longH"pulses
at
peak
average
38 mA
1 ms
long
the rate
of 60 current
Hz. Theof
HEBT
notin
only
carry
thepulses
H- ionat
the rate of 60 Hz. The HEBT not only carry the H" ion
but also optically matches linac and ring, correct the
but
also optically
linac
and ring,
energy
jitter frommatches
the linac,
increase
the correct
energy the
spread
energy
jittertofrom
thebeam
linac,stability
increasein
thethe
energy
of beam
avoid
ring,spread
clean the
oftransverse
beam to avoid
stability halo
in thecoming
ring, clean
the the
and beam
longitudinal
from
transverse
and
longitudinal
halo
coming
from
the
linac, characterize the beam from linac, and protect
linac,
characterize
beam fromThe
linac,
and features
protect of
ring from
the faulttheconditions.
general
ring from the fault conditions. The general features of
this line are, the magnetic filed in dipole and
this line are, the magnetic filed in dipole and
quadrupoles and vacuum are low enough to control
quadrupoles and vacuum are low enough to control
Lorentz
and gas stripping of H" for energies 800 -1300
Lorentz and gas stripping of H- for energies 800 –1300
MeV[6].
The
ratio
aperture
to the
beam
MeV[6]. The
ratio
of of
aperture
to the
rmsrms
beam
sizesize
is is
kept
greater
than
10
through
out
the
line
except
energy
kept greater than 10 through out the line except energy
corrector, spreader
, spreaderandand
collimators.
Figure
1 shows
corrector
collimators.
Figure
1 shows
the
layout
of
the
HEBT,
Ring
and
RTBT.
For
the layout of the HEBT, Ring and RTBT. For easeease
of of
operation
and
stability
reasons
the
lattice
of
the
operation and stability reasons the lattice of the is is
chosenis isFODO
FODOwhich
which
matches
linac
chosen
matches
thethe
linac
andand
ringring
doublet-FODOlattices.
lattices.Figure
Figure
2 shows
amplitude
doublet-FODO
2 shows
the the
amplitude
function(β(p
) and
dispersion
function
along
x y,p
function
) yand
thethe
dispersion
function
(η) (r|)
along
x ,β
theHEBT.
HEBT.
We
consider
HEBT
as having
three
the
We
cancan
consider
thethe
HEBT
as having
three
sections:Linac-Achromat
Linac-Achromat
Matching
Section
(LAMS),
sections:
Matching
Section
(LAMS),
Achromat,and
andAchromat-Ring
Achromat-RingMatching
Matching
Section
Achromat,
Section
(ARMS).
to to
thethe
bend
to the
ring,
there
is ais a
(ARMS).InInaddition
addition
bend
to the
ring,
there
straight
straight beam
beam line
line used
used for for linac
linacbeam
beam
characterization,
in in
Fig.Fig.
1. 1.TheThe
firstfirst
fivefive
characterization,as asshown
shown
cells
linac
(LAMS)
are are
usedused
to to
cells(8(8m/cell)
m/cell)after
afterthethe
linac
(LAMS)
characterize
the
linac
beam,
match
beam
into
the
characterize the linac beam, match beam into the
achromat,
beam
halo.
TheThe
energy
corrector
achromat,collimate
collimate
beam
halo.
energy
corrector
cavity
is
located
in
the
last
half
cell
of
the
LAMS.
cavity is located in the last half cell of the
LAMS.
Following
thethe
four
cellcell
long
achromat
(14(14
m/cell)
Followingthis,
this,
four
long
achromat
m/cell)
provides
selection
by by
cleaning
up the
beam
providesmomentum
momentum
selection
cleaning
up the
beam
energy
dispersion
energyhalo
haloat atthethepoint
pointof ofmaximum
maximum
dispersion
(ηx=6.4m). The remaining six cells (8 m/cell) are used
(r| =6.4m). The remaining six cells (8 m/cell) are used
for xmatching the beam into the accumulator ring,
for matching the beam into the accumulator ring,
diagnostics. The energy spreader cavity is located in
diagnostics. The energy spreader cavity is located in
the first cell following the achromat (in the ARMS),
the
cell following
thederivative
achromatare(inzero.
the There
ARMS),
wherefirst
the dispersion
and its
where
the
dispersion
and
its
derivative
are
zero.
There
are eight horizontal and eight vertical dipole correctors
are
eight
horizontal
and
eight
vertical
dipole
correctors
placed in strategic positions of small apertures in the
placed in strategic positions of small apertures in the
CP642, High Intensity and High Brightness Hadron Beams: 20th ICFA Advanced Beam Dynamics Workshop on
High Intensity and High Brightness Hadron Beams, edited by W. Chou, Y. Mori, D. Neuffer, and J.-F. Ostiguy
© 2002 American Institute of Physics 0-7354-0097-0/02/$ 19.00
130
line. The line has following new features to control
losses.
line.
line. The
The line
line has
has following
following new features to control
losses.
losses.
FIGURE 2. The βx ,βy and ηx along the HEBT.
FIGURE 2.
2. The
The pβxx ,p
,βyy and r|ηxx along
along the
the HEBT.
HEBT.
FIGURE
Transverse and Longitudinal Collimators
Transverse and
and Longitudinal
Longitudinal Collimators
Transverse
To remove the transverse and longitudinal halo
To remove
remove the
the transverse
transverse and longitudinal halo
To
from
the
beam,
we
introduce
adjustable carbon foils in
from
the
beam,
we
introduce
adjustable carbon foils in
frompath
the beam,
we introduce
adjustable
the
of
beam
to
intercept
the tails. After the
the path
path of
of beam
the
-beam to intercept the tails. After the
- ion through the foil, the two electrons
passage
the
H
ion through
through
the foil,
passage the
the H"
H ion
passage
the
foil, the
the two
two electrons
electrons
are
H
focusing lattice
lattice deviatesthe
the
areremoved
removed and
and the
the H"
H- focusing
focusing
are
removed
and
the
lattice deviates
deviates the
proton
tails
into
large
massive
absorbers.
There
are
proton
tails
into
large
massive
absorbers.
There
are
proton tails into large massive absorbers. There are aa a
total
foil.Four
Fourtransverse
transverse
totalof
offive
fiveset
set of
of such
such
adjustable
total
of
five
set
of
such adjustable
adjustable foil.
foil.
Four
transverse
(2(2
in
x
and
y)
are
located
just
after
linac
andfifth
fifth
(2each
each
in
x
and
y)
are
located
just
after
linac
each in x and y) are located just after linac and
and
fifth
one
is
located
in
the
achromat
at
the
high
dispersion[7]
one
is
located
in
the
achromat
at
the
high
dispersion[7]
one is located in the achromat at the high dispersion[7]
60 60
40 40
20 20
0
0
-20 15
-20 15
-40
17
17
19
19
21
21
23
23
25
25
27
27
29
29
31
31
-40
-60
-60
FIGURE 3.
Carbon foils
foils and
and absorber
FIGURE
Carbon
layout
inin
FIGURE
3.3. Carbon
foils
and absorber
absorberlayout
layoutin
HEBT.
HEBT.
HEBT.
Figure 33 shows
shows the
the layout
layout of
of the
the adjustable
adjustable foils
and
Figure
foils
and
Figure
3 shows
the layout
of between
the adjustable
foils
and
absorbers.
The
phase
advance
adjustable
foils
absorbers. The
The phase
phase advance
advance between
adjustable
foils
absorbers.
between
adjustable
foils
is 90°
90° (in
(in each
each plane)
plane) providing
providing the
most efficient
cut
the
cut
isisof90°
(inphase
each plane)
providing
the most
mostefficient
efficient
cut
the
space.
For
H
collimation
by
charge
of
the
phase
space.
For
H"
collimation
by
charge
ofexchange
the phase
space. For ofHthecollimation
by by
charge
the interception
secondary halo
the
exchange the
the interception
interception of
the
halo
bybythe
exchange
the secondary
secondary
haloimpact
the
absorber is 100%
efficient.of Still,
due to small
absorber
is
100%
efficient.
Still,
due
to
small
impact
absorber
is 100%
efficient.
Still,
due toprobability
small impact
parameters,
the protons
have
a finite
of
parameters, the protons have a finite probability of
parameters,
theabsorber
protons without
have a being
finite removed.
probability
escaping the
Weof
escaping the absorber without being removed. We
simulate the
of protons
material of
escaping
the passage
absorber
withoutthrough
being the
removed.
We
simulate the passage of protons through the material of
the absorber
with Monte
Carlo through
code. The
absorption
simulate
the
passage
of
protons
the
material
the absorber with Monte Carlo code. The absorptionof
efficiency
forwith
the Monte
secondary
protons
ranges
88 to 95
the
absorberfor
Carlo
code.ranges
The absorption
efficiency
the secondary
protons
88 to 95
%.
efficiency
for the secondary protons ranges 88 to 95
%.
%. For longitudinal halo collimation, a charge
For longitudinal
halo
collimation,
a charge
exchange
foil is located
in high
dispersion region
in
For longitudinal
halo
collimation,
a charge
exchange
foil
is
located
in
high
dispersion
region
in
the
HEBT
achromat
to
remove
the
longitudinal
tails
exchange
foil
is located
in highthe
dispersion
region
in
the
HEBT
achromat
to
remove
longitudinal
tails
from the beam before entering the ring. After being
the
HEBT
achromat
to
remove
the
longitudinal
tails
from
the the
beam
beforeare
entering
thebyring.
stripped,
protons
deviated
the After
dipole being
filed
from
the
beam
before
entering
the
ring.
After being
stripped,
the
protons
are
deviated
by
the
dipole
into a large absorber outside the beam trajectory. filed
The
stripped,
the
protons
areafter
deviated
the
dipole The
filed
into
a large
outside
the beam
trajectory.
vacuum
pipeabsorber
geometry
foil
hasbybeen
adjusted
to
vacuum
pipeabsorber
geometry
after foil
been
adjusted The
to
into
a large
outside
the has
beam
trajectory.
vacuum pipe geometry after foil has been adjusted to
131
clear the dipole and drive the protons on the absorber.
In
this
case,
the
absorption
efficiency
in the
collimator
clear the
the dipole
dipole and
and drive
drive the
the protons
protons on
on the
theabsorber.
absorber.
clear
is
100%,
as
protons
are
deviated
from
the
main path
In this
this case,
case, the
the absorption
absorption efficiency
efficiency ininthe
thecollimator
collimator
In
and
hit
the
absorber
located
outside
the
accelerator.
is 100%,
100%, as
as protons
protons are
are deviated
deviated from
from the
the main
main path
path
is
and hit
hit the
the absorber
absorber located
located outside
outsidethe
theaccelerator.
accelerator.
and
Energy Corrector and Spreader Cavity
Corrector
and
Spreader
Cavity
Energy
Corrector
Cavity
Beam
from and
theSpreader
linac will
have 2.0 MeV energy
jitter
and
3.5°the
forlinac
phase
jitter
due
0.5° energy
and
0.5 %
Beam
from
the
linac
will
have
2.0toMeV
MeV
energy
Beam
from
will
have
2.0
amplitude
error
linac.
To and
remove
these
jitter
and 3.5°
3.5°control
for phase
phase
jitterindue
due
0.5°
and
0.5%%
jitter
and
for
jitter
toto 0.5°
0.5
phase and
amplitude
MHz
(linac
amplitude
control
error
linac.
To
remove
these
amplitude
control
error ininjitter
linac. an
To 805
remove
these
phase
and
an
805
MHz
phase
and amplitude
amplitude
jitter
anjust
805
MHz
(linac
frequency)
RF cavity jitter
is
place
before
the(linac
achromat
frequency)
cavity
isis place
before
the
achromat
frequency)
RF
cavity
place
just
before
theparticle
achromat
which isRF
phase
lock
to thejust
linac.
The
due to
which
is
lock
the
which
is phase
phase
lock to
towill
the linac.
linac.
The
particle
due
energy
difference
sufferThe
theparticle
phasedue
sliptotowith
energy
energy
difference
will suffer
suffer the
the phase
phase
slip with
with
respectdifference
to design will
momentum
given
by slip
respect
respect to
to design
design momentum
momentumgiven
givenby
by
γ
∆T L
2πf
∆φ ≡ γ
T L
∆AT
φ L ≡L — γ7—
∆A,*
γ +——
1) T 2βπcf
(
γ (γ + 1) T βc
where β,γ are the relativistic parameters, T is the
where
β,γ
are
relativistic
parameters,
TT isis the
where
p,ykinetic
are the
the
relativistic
parameters,
the l is
design
energy
and
fthe
is
the frequency
and
design
kinetic
energy
and
f
is
frequency
and
l 1isis
design
kinetic
energy
and
f
is
the
frequency
and
length for
the phase
slip. The
required voltage
is given
length
length for
for the
the phase
phase slip.
slip. The
The required
required voltage
voltageisisgiven
given
by
V
=∆E/sin(φ
).
The
energy
jitter
after
the
0
Slip
by
Slip). The
by V
V00=∆E/sin(φ
=AE/sin((|)siip).
The energy
energy jitter
jitter after
after the
the
corrector
cavity
0.2
MeV
was
achieved
which
is
corrector
corrector cavity
cavity 0.2
0.2 MeV
MeV was
was achieved
achieved which
which isis
within
the
requirement
of
the
ring.
within
within the
the requirement
requirement of
ofthe
thering.
ring.
SNS
accumulator
need
4 MeV
energy
SNS
accumulator
ring
also
need
±±44±
MeV
energy
SNS
accumulator
ringring
alsoalso
need
MeV
energy
spread
for
stability
reason.
This
is
achieved
by
placing
spread
for
stability
reason.
This
is
achieved
by
placing
spread for stability reason. This is achieved by placing
another
RF
cavity
after
the
achromat
which
frequency
another
cavity
after
achromat
which
frequency
another
RFRF
cavity
after
thethe
achromat
which
frequency
is
100
kHz
different
than
the
frequency.
about
100
kHz
different
the
linac
frequency.
is isabout
about
100
kHz
different
thanthan
thelinac
linac
frequency.
The
linac
bunches
see
different
phase
asasthey
arrive
atat at
The
linac
bunches
different
phase
as they
arrive
The
linac
bunches
seesee
different
phase
they
arrive
this
cavity
and
gain/loss
different
energies
depending
this
cavity
gain/loss
different
energies
depending
this
cavity
andand
gain/loss
different
energies
depending
on
cavity
voltage,
hence
creating
required
energy
cavity
voltage,
hence
creating
required
energy
ononthe
thethe
cavity
voltage,
hence
creating
required
energy
spread
without
creating
energy
tails.
spread
without
creating
energy
tails.
spread
without
creating
energy
tails.
RING
TO
TARGET
TRANSFER
LINE
RING
TO
TARGET
TRANSFER
LINE
RING
TO
TARGET
TRANSFER
LINE
Ring
to
Beam
Transfer
(RTBT)
line
Ring
to Target
Target
Beam
Transfer
(RTBT)
lineisline
isabout
about
Ring
to
Target
Beam
Transfer
(RTBT)
is about
150
meter
long
and
carry
the
beam
from
the
150
meter
long
andand
carry
the the
beam
fromfrom
the ring
ring ring
150
meter
long
carry
beam
the
extraction
region
to
target
and
provide
the
extraction
region
to the
thethe
target
andand
provide
thedesired
desired
extraction
region
to
target
provide
the desired
footprint
for
the
accelerator
complex.
The
general
footprint
for
the
accelerator
complex.
The
general
footprint
for
the
accelerator
complex.
The
general
features of this line are, the line is immune to one
features
of ofthis
lineline
are,are,
thethe
lineline
is is
immune
to one
features
this
immune
to one
kicker failure and the ratio of acceptance to rms
kicker failure and the ratio of acceptance to rms
kicker
failure
and
the
ratio
of
acceptance
to
emittance is more than 20. Figure 4 shows the rms
emittance is more than 20. Figure 4 shows the
emittanceandis the
moredispersion
than 20.function
Figure along
4 shows
amplitude
the the
amplitude and the dispersion function along the
RTBT.
amplitude
and
the
dispersion
function
along
the
RTBT.
RTBT.
The line has following function (a) extraction (b) beam
The line has following function (a) extraction (b) beam
dump
from device
failure(a)
(d) beam spreader
The(c)
lineprotect
has following
function
(b) beam
dump
(c)
protect
from device
failure (d)extraction
beam spreader
and
(e)
diagnostics.
Following
the
extraction
system
dump
(c)
protect
from
device
failure
(d)
beam
spreader
and (e) diagnostics. Following the extraction system
beam
can
be
dumped straight
through
aextraction
16.8° dipole
and
(e)
diagnostics.
Following
the
system
beam canAfter
be dumped
straight
16.8°fordipole
magnet.
the
magnet
two through
cellthrough
are aused
thedipole
beam
can
be
dumped
straight
a
16.8°
magnet. After
thewhich
magnet
two cell
for the
collimator
protect
line are
fromused
dipole
magnet. system
After the
magnet
two
cell
arethe
used
for the
collimator
system
which
protect
line
from
the
failure. Following another six cells of transport,dipole
the
collimator
system
which
protect
line
from
the
dipole
failure.
Following another
sixare
cells
offor
transport,
the
last
five quadrupoles
in the line
used
final beam
failure.
Following
another
six
cells
of
transport,
last
five
quadrupoles
in
the
line
are
used
for
final
beam
spreading to produced the beam sized required at the the
spreading
produced the
beam
required
at thebeam
last five to
quadrupoles
in the
linesized
are used
for final
target.
target.
spreading to produced the beam sized required at the
target.
Beam Spreader
Spreader
^mm
BeamThe
Spreader
beam spreader consists of five radiation
radiation hard
hard
near
the
end
of
the
RTBT.
These
five
quadrupoles
The beam spreader consists of five radiation hard 36
diameter
aperture
provide
cm
provide
the
quadrupoles
near
the endquadrupoles
of the RTBT.
Thesethe
fivedesired
36
size
at
the
target.
Due
to
thermal
considerations
beam
considerations
cm diameter aperture quadrupoles provide the desired
density
on the target
of the
target,
beam
beam
size
at thethe
target.
Duecurrent
to thermal
considerations
22
A/m
.. This
requirement
remainthebelow
requirement
ofmust
the target,
beam 0.25
current
density
on the
target
2
in a non-Gaussian
beam
in
results
distribution
in space
space
must
remain
below 0.25 A/m
. distribution
This requirement
results
in a non-Gaussian
distribution
space
(with un-normalized
rms beam
emittance
of 24
mm
mrad).
24 πnin
mm
mrad).
The un-normalized
required current
distribution
is mrad).
achieved
(with
rmsdensity
emittance
of 24 π mm
achieved
The
required
current
density
distribution
is
achieved
using
painting
scheme
described
elsewhere[8].
elsewhere[8].
using painting scheme described elsewhere[8].
Beam collimation
Beam collimation
The RTBT acceptance is 480 πn mm
mm mrad
mrad and
and the
the
The
RTBTbeam
acceptance
is 480
π mm
mrad
and the
emittance
(100%)
from
the ring
is 240
expected
240
expected
beam The
emittance
ringthat
is 240
line is(100%)
design from
such
aa way
ifif one
nπ mm mrad.
such the
way
that
one
πof
mm
mrad. The
linefail
is design
suchpass
a way
that
oneline
fourteen
kicker
beam will
through
throughifthe
the
line
ofwithout
fourteenscraping.
kicker failTo
beam
will pass
the line
protect
the through
line from
device
device
without
scraping.
To
protect
the
line
from
device
failures such as more than one kicker or
dipole
failure,
or dipole failure,
failures such as more than one kicker or dipole failure,
there are two collimators 90° apart in
in phase
phase advance
advance
there are two collimators 90° apart in phase advance
are placed just after the 16.8° dipole. The acceptances
are placed just after the 16.8° dipole. The acceptances
of these collimators are 300 and 400 πn mm
mrad in
of these collimators are 300 andand
400 π mmmm
mrad in in
horizontal and vertical plane respectively.
horizontal and vertical plane respectively.
FIGURE 4.
4. The
The pβxx ,p
,βyy and
and r|ηxx,,r|ηyy along
alongthe
theRTBT.
RTBT.
FIGURE
FIGURE 4. The βx ,βy and ηx, ηy along the RTBT.
The phase
phase advance
advance between
between kickers and target is
The
Thethat
phase
advance between kickers and target
is
nπ, so
so
in event
event
nrc,
that in
of a kicker failure beam will not
nπ,
so
that
in
event
of
a
kicker
failure
beam
will
not
move at
at the
the target.
target. Figure
Figure 55 shows
shows the
the closed
closed orbit
orbit for
move
move at kickers
the target.
Figure 5 shows the closed orbit for
different
failure.
different
kickers failure.
different kickers failure.
4-
f s
REFERENCES
REFERENCES
Holkamp,
“The
SNS
Linac
Storage
Ring:
1. N.N.
N.Holkamp,
Holkamp,“The
"TheSNS
SNSLinac
Linac
and
Storage
Ring:
1.1.
andand
Storage
Ring:
Challenges
and
Progress
Towards
Meeting
Them”,
Challenges
and
Progress
Towards
Meeting
Them",
Challenges and Progress Towards Meeting Them”,
EPAC2002.
2002.
EPAC
2002.
EPAC
186
2. S.S.
Nath,
“Selected
Aspect
of
Linac”,
EPAC
2.2.
“Selected
Aspect
of SNS
Linac”,
EPAC
S.Nath,
Nath,et et
etal.,al.,
al.,
"Selected
Aspect
of SNS
SNS
Linac",
EPAC
2002
2002
2002
FIGURE
5.
Close
orbit due to
to kickers
kickersfailure.
failure.
FIGURE5.
5.Close
Close orbit
FIGURE
kickers
failure.
J.Wei,
Wei,et et
“Low-Loss
Design
High
Intensity
3.3.
Design
for for
thethe
High
Intensity
3. J.J.
Wei,
etal.,al.,
al.,“Low-Loss
"Low-Loss
Design
for
the
High
Intensity
AccumulatorRing
Ring
Spallation
Neutron
Source”,
Accumulator
thethe
Spallation
Neutron
Source”,
Accumulator
Ringof of
of
the
Spallation
Neutron
Source",
PRST-AB,
080101,
1-19,2001
PRST-AB,
3, 3,
080101,
pp.pp.
1-19,2001
PRST-AB,
3,
080101,
pp.
1-19,2001
frit
Extraction
Extraction
Extraction
Theextraction
extraction of
of the
is done
done
The
extraction
of
the beam
beam is
done in
in aaa single
singleturn
turn
The
in
single
turn
with
full
aperture
at
repetition
frequency
of
with
full
aperture
at
a
pulse
repetition
frequency
of
60
with full aperture at a pulse repetition frequency of60
60
Hz.
The
extraction
system
consists
of
two
sets
(seven
Hz.
The
extraction
system
consists
of
two
sets
(seven
Hz. The extraction system consists of two sets (seven
each) kicker
kicker magnets
magnets and
and aaa Lambertson
Lambertson
each)
kicker
magnets
and
Lambertson magnet
magnet
each)
magnet
septum
and
a
dipole
magnet.
The
septum and
and aa dipole
dipole magnet.
magnet. The
The Lambertson
Lambertson septum
septum
septum
Lambertson
septum
magnet will
will receive
receive the
the vertically
vertically kicked
magnet
kicked down
down beam
beam
magnet
will receive
the vertically
kicked
down
beam
and
will
provide
large
deflection
angle
(16.8°)
and will
will provide
provide large
large deflection
deflection angle
angle (16.8°)
(16.8°) toto
to
and
enableejection
ejection horizontally
horizontally
from
the
accumulator
ring.
enable
from
the
accumulator
ring.
enable
ejection
horizontally
from
the
accumulator
ring.
dipole, which
which is
is 540°
540° phase
phase advance
AAdipole,
dipole,
advance away
awayfrom
fromthe
the
A
which
is 540°
phase
advance
away
from
the
Lamberton
magnet,
bends
the
beam
horizontally
ininthe
Lamberton
magnet,
bends
the
beam
horizontally
the
Lamberton
magnet,
bendsmaking
the beam
in the
same direction
by 16.8°,
thehorizontally
extraction system
same
direction
by
16.8°,
making
the
extraction
system
same
directionThe
by Lambertson
16.8°, making
the extraction
achromatic.
magnet
is rotated system
2.55°
achromatic. The
The Lambertson
Lambertson magnet
magnet is
is rotated
rotated 2.55°
2.55°
achromatic.
anti-clock wise to neutralize the vertical kick
from the
anti-clock
wise
to
neutralize
the
vertical
kick
from
the
anti-clock
wise
to neutralize
vertical
kickdifference
from the
kickers and
making
the beamthe
about
9 inches
kickers
and
making
the
beam
about
9
inches
difference
kickers
and
theRTBT
beambeam
aboutheight.
9 inches difference
between
themaking
ring and
between the
the ring
ring and
and RTBT
RTBT beam
beam height.
height.
between
4.4.
NSNS
High
Energy
Beam
4. D.D.
Raparia,
“The
NSNS
High
Energy
Beam
D. Raparia,
Raparia,et et
etal.,al.,
al.,“The
"The
NSNS
High
Energy
Beam
Transport
Line”,
Proc.
1997
Particle
Accelerator
Transport
Line”,
Proc.
1997
Particle
Accelerator
Transport Line", Proc. 1997 Particle Accelerator
Conference,
p. p.
162.
Conference,
162.
Conference,
p.
162.
5.5. D.D.Raparia,
et al.,al.,“The
SNS Ring
to Target
Beam
5. D. Raparia,
Raparia, et
et al., “The
"The SNS
SNS Ring
Ring to
to Target
Target Beam
Beam
Transport
Line”,
Proc.
1999
Particle
Accelerator
Transport
Line”,
Proc.
1999
Particle
Accelerator
Transport
Line",
Proc.
1999
Particle
Accelerator
Conference,
p. p.
1297.
Conference,
Conference,
p. 1297.
1297.
6.6.D.D.Raparia,
et
al.,
“Dependence
of the
SNS Transfer
lineslines
Raparia, et
“Dependence
of
the
Transfer
6. and
D. Raparia,
et al.,
al.,Ring
"Dependence
of Energy”,
the SNS
SNS Proc.
Transfer
lines
Accumulator
on on
thethe
Linac
2001
and
Accumulator
Ring
Linac
Energy”,
Proc.
2001
and
Accumulator
Ring
on
the
Linac
Energy",
Proc.
2001
Particle
Accelerator
Conference,
p. 3260.
Particle
Accelerator
Conference,
p. 3260.
Particle Accelerator Conference, p. 3260.
7. N. Catalan-Lasheras, and D. Raparia, “The Collimation
7. N.
N. Catalan-Lasheras,
and
Raparia,
“The Collimation
7.
Catalan-Lasheras,
and D.
D.
Raparia,
System
of the SNS Transfer
Lines,
Proc. "The
2001 Collimation
Particle
System
of
the
SNS
Transfer Lines,
Proc.
2001
System
of
the
SNS
Transfer
Lines,
Proc.
2001 Particle
Particle
Accelerator Conference, p. 3263.
Accelerator Conference,
Accelerator
Conference, p.
p. 3263.
3263.
8. J. Beebe-Wang, et al., “Transverse Phase Space Painting
8.
J.
et
“Transverse
Phase
Painting
8. for
J. Beebe-Wang,
Beebe-Wang,
et al.,
al., Ring
"Transverse
Phase
Space 1999
Painting
SNS Accumulator
Injection”,
, Space
Proc.
for
SNS
Accumulator
Ring
Injection”,
,
Proc.
Particle
Accelerator
Conference,
p.
1743.
for SNS Accumulator Ring Injection", , Proc. 1999
1999
Particle
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p.
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132