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


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)


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


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


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


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


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


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


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


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


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


ABS beam profileABS beam profile

σ = 2.85 ± 0.42


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


Apertures tests at COSYApertures tests at COSY

COSYbeam

XY-table Frame with apertures

Vacuum camber


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


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


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


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…

The Polarized Internal Gas Target of ANKE at COSY

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