The Polarized Internal Gas Target of ANKE at COSY
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Transcript of The Polarized Internal Gas Target of ANKE at COSY
The Polarized Internal Gas TargetThe Polarized Internal Gas Targetof ANKE at COSYof ANKE at COSY
1616thth International Spin Physics Symposium International Spin Physics Symposium
Trieste, ItalyTrieste, Italy
OOctober 15ctober 15,, 2004 2004
Kirill GrigorievKirill Grigoriev
Institute for Nuclear Physics (IKP) Institute for Nuclear Physics (IKP)
Forschungszentrum, JülichForschungszentrum, Jülich
15.10.200415.10.2004 Kirill Grigoriev @ SPIN'04Kirill Grigoriev @ SPIN'04 22
OutlineOutline
• IntroductionIntroduction• Atomic Beam SourceAtomic Beam Source• Lamb-Shift Lamb-Shift PPolarimeterolarimeter• StorageStorage Cell prototypesCell prototypes• Apertures tApertures testest at COSY at COSY• OutlookOutlook
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COSY COSY COoler SYnchrotron COoler SYnchrotron
COSY:
• storage ring for polarized proton and deuteron beams• with momentum range 600 - 3700 MeV/c
COSY used for:
• internal experiments - with the circulating beam (ANKE, COSY-11, EDDA, PISA)• external experiments - with the extracted beam (BIG KARL, JESSICA, NESSI, TOF)
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ANKE at COSYANKE at COSY
Targets• Solid strip• Cluster• Polarized
Magnets• D2 – spectrometer magnet• D1, D3 – beam bending magnets
Detector systems• Positive & Negative• Forward & Backward• Spectator Detectors
Spectrometer ANKE
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PIT at ANKEPIT at ANKE
Technical constraints• Installation time of the PIT is limited to 3-4 days
• D2 is movable →→ needs sophisticated supporting bridge between D1 and D2
• Tunnel width is limited →→ 60° angle between LSP components
• ABS axis is 50 cm away from D2 yoke →→ shielding from the stray field is needed Polarized internal gas target setup at ANKE
Storage cellPolarimeter
ABS
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Stray field MAFIA calculationStray field MAFIA calculation
x
y
z
Field map cut at the storage cell center(COSY coordinate z = 0)
xx
yy
60-90 G135 G
5-6 G30 G
30 G55 G
35-45 G300 G
200 G300 G
50-60 G300 G
30 G55 G
30 G - calculated field magnitude55 G - permissible field of device
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Laboratory SetupLaboratory Setup
Setup at the laboratory
Setup at the laboratory consist of:
• Atomic Beam Source
• Test chamber with storage cell prototype
• Lamb-Shift Polarimeter
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Atomic Beam SourceAtomic Beam Source
PI I ~ 10 mbar-6
PI ~ 10 mbar-4
PI II ~ 10 mbar-7
PIV ~ 10 mbar-8
1st group of 6-pole magnetsPole-tip fields are:
#1 1.654 T 10/14 mm
#2 1.684 T
#3 1.625 T
16/22 mm
mm28
2nd group of 6-pole magnetsPole-tip fields are:
#4 1.565 T
#5 1.621 T
#6 1.621 T
30 mm
30 mm
30 mm
Nozzle cooling systemTemperature range: 50-300 K
DissociatorPrimary flow (H /D ) range: 1 10 - 5 mbar l/s
Second2 2 -3
ary flow (O ) range: 1 10 - 0.5 mbar l/sRF power: 0 - 600 W @ 13.56 MHz
2 -3
Medium Field Transition unit (MFT)Frequency: 58.7 MHz (H )Magnetic field: up to ~ 2 kG
2
Strong Field Transition unit (SFT)Frequency: 1425.2 MHz (H )Magnetic field: up to ~ 3 kG
2
Weak Field Transition unit (WFT)Frequency: 14 MHz (H )Magnetic field: up to ~ 3 kG
2
Movable bafflesAl casting
Central reference platestainless steel (t ~ 50 mm)
H beam intensity~ 8.0x1016 at/s
hig
h f
req
uen
cy
tra
nsi
tio
n u
nit
hf onhf off
rf dissociatorH H + H2
sp
in s
epa
rati
on
6
-po
le m
ag
net
sWorking principle
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Lamb-Shift PolarimeterLamb-Shift Polarimeter
Lamb-Shift Polarimeter layout
B
N
Typical Ly-α spectrum
I o n is e r C s c e l l S p in f i l t e rQ u e n c h in g
c h a m b e r
Ph
oto
mu
ltip
lie
r
t
B
BB B
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ABS beam polarization measurementsABS beam polarization measurements
Ly-α spectra of hydrogen and deuterium measured with LSP
Hydrogen
P = 0.89±0.01z
P = –0.96±0.01z
300 350 400 450 500 550Magnetic field, a.u.
P
P
z
z
(Ly-a) = +0.78MFT 2-3teor= +1
mI=–1/2
50 100 150 200 250 300 350 400 450 500 5500
20406080
100120140160180
N(Ly
-)
P
P
z(Ly-a) = -0.86MFT 2-3WFT 1-3
= -1zteor
mI=+1/2
mI=–1/2
Deuterium
P = 0.73±0.05z P = –0.82±0.06z
500 550 600 650 700 750 800 85040
60
80
100
120
140
160 P
P
z(Ly- ) = +0.68
MFT 3-4SFT 2-6
P
P
zz
z
(Ly- ) = +0.68
= +1= +1
z
z
teor
teor
N(Ly
-)
mI=+1
mI=–1mI=0
500 550 600 650
40
60
80
100
120
140 P
P
z(Ly- ) = -0.76
MFT 3-4WFT 1-4 2-3
P
P
zz
z
(Ly- ) = +0.57
= -1= +1
z
z
teor
teorN(Ly
-)
mI=+1 mI=0
P = 0.77±0.06zz P = –1.17±0.08zz
500 550 600 650 700 750 800 850
40
60
80
100
120P
P
z(Ly- ) = 0
WFT 1-4SFT 2-6
P
P
zz
z
(Ly- ) = +0.72
= 0= +1
z
z
teor
teor
N(Ly
-) mI=+1 mI=–1
mI=0
500 550 600 650
40
60
80
100
120
140
N(Ly
-)
mI=+1
mI=0
Magnetic field, a.u.
Magnetic field, a.u. Magnetic field, a.u.
Magnetic field, a.u. Magnetic field, a.u.
150 200 2500
20406080
100120140160180
N(Ly
-)
mI=+1/2
700 750 800 850
mI=–1
700 750 800 850
P
P
z(Ly- ) = -0.06
WFT 1-4SFT 3-5
P
P
zz
z
(Ly- ) = -1.09
= 0= -2
z
z
teor
teor
mI=–1
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PIT test setupPIT test setupA
tom
ic B
eam
Sou
rce
Storagecell prototype
Ioniser Wien filter Cs cell Spin filterQuenchingchamber
Pho
tom
ultip
lier
tB
B B B B
Layout of the test setup at laboratory
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ABS beam profile at cellABS beam profile at cell
Storage cell prototype Top view of beam profile on glass with molybdenum oxide
ABSbeam
COSYbeam
COSYbeam
beamextractedfrom cell
COSYbeam
COSYbeam
beamextractedfrom cell
ABSbeam
ABSbeam
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ABS beam profileABS beam profile
σ = 2.85 ± 0.42
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Cell prototypeCell prototype
ABSbeam
COSYbeam
Target gassample
Beams directions at storage cell
ABS beam profile is known
• Target gas sample profile can be simulated if shapes of all tubes are known
COSY beam profile should be analyzed
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Apertures tests at COSYApertures tests at COSY
COSYbeam
XY-table Frame with apertures
Vacuum camber
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Principle of the apertures tests at COSYPrinciple of the apertures tests at COSY 1. Beam in the center of the aperture
50 mm
2. Aperture moves to the right until intensity drops +5 mm
3. Aperture moves to theleft until intensity drops 11 mm
Beam diameter = Aperture inner width - ( Distance 2 + Distance 3 )
Beam intensity is maximum
0
100
200
300
400
500
600
700
800
-25 -20 -15 -10 -5 0 5 10 15 20 25
X coordinates, mm
bea
m in
ten
sity
, a.u
.
Beam intensity start decrease
0
100
200
300
400
500
600
700
800
-25 -20 -15 -10 -5 0 5 10 15 20 25
X coordinates, mm
bea
m i
nte
nsi
ty,
a.u
.
Distance 2
Beam intensity start decrease
0
100
200
300
400
500
600
700
800
-25 -20 -15 -10 -5 0 5 10 15 20 25
X coordinates, mm
bea
m i
nte
nsi
ty,
a.u
.
Distance 3
Distance 2
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Apertures tests at COSYApertures tests at COSY
Tests at injection Tests with an accelerated beam
0
100
200
300
400
500
600
700
800
-25 -20 -15 -10 -5 0 5 10 15 20 25
X coordinates, mm
bea
m i
nte
nsi
ty,
a.u
.
0
100
200
300
400
500
600
700
800
-12.5 -10 -7.5 -5 -2.5 0 2.5 5 7.5 10 12.5
Y coordinates, mm
be
am
inte
ns
ity
, a.u
.
0
0.2
0.4
0.6
0.8
1
-25 -20 -15 -10 -5 0 5 10 15 20 25X beam position, mm
be
am
in
ten
sit
y, a.u
.
target ON target OFF
0
0.2
0.4
0.6
0.8
1
-12.5 -10 -7.5 -5 -2.5 0 2.5 5 7.5 10 12.5
Y beam position, mm
be
am
in
ten
sit
y, a.u
.
target ON target OFF
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Estimated COSY-beam profileEstimated COSY-beam profile
at injection
with an accelerated beam
cluster target offcluster target on
(density ~ 1014 at/s)
36x16 mm 9x12 mm 16x15 mm
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Time scheduleTime schedule
Before end 2004 – transfer of ABS and LSP
to COSY hall
Spring 2005 – cell prototype tests at ANKE with
unpolarized storage cell target
Summer 2005 – first installation of PIT at COSY,
commissioning and initial research
After all – ready for all kinds of experiments
with Polarized Internal Gas Target !!!
in progress…
approved…
to be scheduled…