the polarized internal gas target of anke at cosy
DESCRIPTION
The Polarized Internal Gas Target of ANKE at COSY. Ralf Engels Institute for Nuclear Physics (IKP) Forschungszentrum Jülich. PST 05 Tokyo, Japan November 16, 200 5. COSY COoler SYnchrotron. COSY: storage ring for (un-) polarized proton and deuteron beams - PowerPoint PPT PresentationTRANSCRIPT
The Polarized Internal Gas TargetThe Polarized Internal Gas Targetof ANKE at COSYof ANKE at COSY
PST 05PST 05
Tokyo, JapanTokyo, Japan
November 16,November 16, 200 20055
Ralf EngelsRalf Engels
Institute for Nuclear Physics (IKP) Institute for Nuclear Physics (IKP)
Forschungszentrum JülichForschungszentrum Jülich
16.11.200516.11.2005 Ralf Engels @ PST 05Ralf Engels @ PST 05 22
COSY COSY COoler SYnchrotron COoler SYnchrotron
COSY:
• storage ring for (un-) polarized proton and deuteron beams• with momentum up to 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)
16.11.200516.11.2005 Ralf Engels @ PST 05Ralf Engels @ PST 05 33
PIT setupPIT setup
Setup at the laboratory
Polarized internal gas target setup at the laboratory consist of:
• Atomic Beam Source
• Test chamber with storage cell prototype
• Lamb-Shift Polarimeter
16.11.200516.11.2005 Ralf Engels @ PST 05Ralf Engels @ PST 05 44
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
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ABS beam profileABS beam profile
σ = 2.85 ± 0.42 mm
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Ionizer
Wien filter Cs cell Spin filterQuenchingchamber
Ph
otom
ultip
lier
tB
B
B
Cup
ABS
Deflector
B B
Lamb-Shift Polarimeter layoutLamb-Shift Polarimeter layout
16.11.200516.11.2005 Ralf Engels @ PST 05Ralf Engels @ PST 05 77
ABS beam polarization measurementsABS beam polarization measurements
Ly-α spectra of hydrogen and deuterium measured with LSP
Hydrogen
P = 0.89 0.005z ±
P = –0.96z ± 0.005
300 350 400 450 500 550
Magnetic field, a.u.
P
P
z
z
(Ly-a) = +0.78MFT 2-3
teor= +1
mI=–1/2
50 100 150 200 250 300 350 400 450 500 5500
20
40
60
80
100
120
140
160
180
N(L
y-a)
P
P
z(Ly-a) = -0.86MFT 2-3WFT 1-3
zteor
= -1
mI=+1/2
mI=–1/2
Deuterium
P = 0.73z P = –0.82z
500 550 600 650 700 750 800 850
40
60
80
100
120
140
160 P
P
z(Ly- ) = +0.68
MFT 3-4SFT 2-6
aP
P
zz
z
(Ly- ) = +0.68
= +1= +1
a
z
z
teor
teor
N(L
y-)
a
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
aP
P
zz
z
(Ly- ) = +0.57
= -1= +1
a
z
z
teor
teor
N(L
y-)
a
mI=+1 mI=0
P = 0.77zz P = –1.17zz
500 550 600 650 700 750 800 850
40
60
80
100
120P
P
z(Ly- ) = 0
WFT 1-4SFT 2-6
aP
P
zz
z
(Ly- ) = +0.72
= 0= +1
a
z
z
teor
teor
N(L
y-)
a
mI=+1 mI=–1
mI=0
500 550 600 650
40
60
80
100
120
140
N(L
y-)
a
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
20
40
60
80
100
120
140
160
180
N(L
y-a)
mI=+1/2
700 750 800 850
mI=–1
700 750 800 850
P
P
z(Ly- ) = -0.06
WFT 1-4SFT 3-5
aP
P
zz
z
(Ly- ) = -1.09
= 0= -2
a
z
z
teor
teor
mI=–1
16.11.200516.11.2005 Ralf Engels @ PST 05Ralf Engels @ PST 05 88
Ato
mic
Be
am
Sou
rce
Storagecell prototype
Ionizer Wien filter Cs cell Spin filterQuenchingchamber
Pho
tom
ultip
lier
tB
BB B B
Cup
How to measure polarization in the cellHow to measure polarization in the cell
Layout of the test setup at laboratory
ABSbeam
COSYbeam
Target gassample
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LSP resultsLSP results
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LSP resultsLSP results
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How to measure polarizationHow to measure polarization
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PIT at COSY hallPIT at COSY hall
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PIT transportationPIT transportation
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PIT @ ANKEPIT @ ANKE
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PIT @ ANKEPIT @ 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 measurementsStray field measurements
x
y
z
90 G150 G135 G
6 G15 G30 G
30 G25 G55 G
40 G26 G300 G
200 G550 G300 G
60 G100 G300 G
30 G33 G55 G
30 G - maximum calculated field magnitude45 G - measured field magnitude55 G - allowed field for device
30 G17 G
150 G48 G
30 G - measured field without shielding 17 G - measured field with shielding
x
y
z
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0.00E+00
5.00E-08
1.00E-07
1.50E-07
2.00E-07
2.50E-07
3.00E-07
0 200 400 600 800 1000 1200 1400
Current in D2, A
Pre
ssu
re in
th
e ta
rget
ch
amb
er, m
bar
.
beam off beam on, no polarization beam on, with polarization
1.00E-08
Polarization test with D2 fieldPolarization test with D2 field
Pz ~ 0.80
16.11.200516.11.2005 Ralf Engels @ PST 05Ralf Engels @ PST 05 1818
Apertures tests at COSYApertures tests at COSY
COSYbeam
XY-table Frame with apertures
Vacuum chamber
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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
Distance 3
Distance 2
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 starts to 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 starts to 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
.
16.11.200516.11.2005 Ralf Engels @ PST 05Ralf Engels @ PST 05 2020
Estimated COSY-beam profileEstimated COSY-beam profile
at injection with an accelerated beam
no target with cluster target(density ~ 1014 at/cm2)
36x16 mm 9x12 mm 16x15 mm
16.11.200516.11.2005 Ralf Engels @ PST 05Ralf Engels @ PST 05 2121
Cell test preparationCell test preparation
Aperture → 40 x 25 mm
Big cell → 30 x 20 x 220 mm entrance 600 mm2
Small cell → 15 x 15 x 220 mm entrance 225 mm2
16.11.200516.11.2005 Ralf Engels @ PST 05Ralf Engels @ PST 05 2222
PRELIMIN
ARY
Results of the cell testResults of the cell test
Target densityfor the large cell
9.4 * 10132cm
at Ratio target/backgroundfor the large cell
~ 3 – 4
Injected deuteronslarge/small cell ~ 7 – 8 Estimated target density
H2 for the small cell ~3 * 1014
2cm
at
Tests were carried out with unpolarized hydrogen gas flux ~ 10-3 mbar l/s
No cooling of the ion beam !!!
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SummarySummary
• PIT moved to COSY hall since December 2004
• PIT installed at ANKE in June-July 2005
• PIT is running since September 2005
• Cell tests without cooling in Spring 2005
Cell tests with electron cooling shifted to November 2005
• LSP will be used to measure direct beam of the ABS
• Polarization in the cells determined by the Spectator counters
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OutlookOutlook
November ’05 – next cell tests with cooling and stacking of the COSY beam
November ’05 – commissioning of the ABS-jet target at COSY
Winter ’05-’06 – ANKE target exchange from PIT to Cluster target
May ’06 – one more week for cell test at COSY
Until June ‘06 – more tests with LSP in COSY hall
new cell production with teflon coating
ISTC project 1861 : “Measurement of the nuclear
polarization in H2 / D2 molecules”
Summer ’06 – PIT reinstallation at ANKE
Autumn ’06 – first data production with jet target at ANKE
(http://www.fz-juelich.de/ikp/anke/en/proposals.shtml)
Polarized fusion
16.11.200516.11.2005 Ralf Engels @ PST 05Ralf Engels @ PST 05 2525
ISTC project 1861ISTC project 1861
16.11.200516.11.2005 Ralf Engels @ PST 05Ralf Engels @ PST 05 2626
Polarized fusionPolarized fusion
LSP
Electrostatic lenses
IonizerInsulator
2D silicon strip detectors “Interaction box”
potential 1kV-200kV
“Hot” magnets for holding field
LSP under thepotential respectto the “ground” 500V
Cryopump
90 electrostatic deflectors
o
Wienfilter
ABS