The Polarized Internal Target at ANKE: First Results
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The Polarized Internal Target at ANKE:First Results
Kirill Grigoryev
Institut für Kernphysik, Forschungszentrum Jülich
PhD student from Petersburg Nuclear Physic Institute (PNPI),Gatchina, Russia
Kyoto
October 03, 2006
03.10.2006 Kirill Grigoryev @ SPIN2006 2
COSY COoler SYnchrotron
• internal experiments – with the circulating beam (ANKE, COSY-11, EDDA)
• external experiments – with the extracted beam (BIG KARL, TOF)
with momenta up to 3.7 GeV/c
ANKE at COSY
Targets• Solid strip• Cluster jet• Polarized gas cell ( polarized gas jet )
Magnets• D2 – spectrometer magnet• D1, D3 – beam bending magnets
Detector systems• Positive & Negative• Forward & Backward• Spectator Detectors
Spectrometer ANKE
p, p, d, d→ →
03.10.2006 Kirill Grigoryev @ SPIN2006 3
Polarized Internal Gas Target
Setup at the laboratory
Summer 2003 – Atomic Beam Source is ready for using in experiments
PIT main components:ABS
• H or D• H beam intensity (2 HFS)
7.6 . 1016 atoms/s• Beam size at the IP
σ = 2.85 ± 0.42 mm• Polarization for hydrogen
PZ = 0.89 ± 0.01
PZ =-0.96 ± 0.01
Lamb-Shift PolarimeterTarget chamber with Storage Cell
Setup at the COSY experimental hall
End of 2004 – Start of the PIT transportation to the COSY experimental hall
ABS with infrastructure at the COSY experimental hall
Summer 2005 – After commissioning source is ready for installation at COSY
Setup at ANKE at COSY
July 2005 – ABS is installed at the ANKE-experiment area at COSY
Work only
Work only
beginsbegins
03.10.2006 Kirill Grigoryev @ SPIN2006 4
Magnetic Stray Field from D2 Magnet
x
y
z
90150135
61530
302555
4026300
200550300
60100300
303355
calculated field strength (G)measured field strength (G)permissible field strength for the device
given by the producer (G)
x
y
z
90150135
61530
302555
4026300
200550300
60100300
303355
x
y
zx
y
z
90150135
61530
302555
4026300
200550300
60100300
303355
calculated field strength (G)measured field strength (G)permissible field strength for the device
given by the producer (G)
ABS with shielded components at ANKE
03.10.2006 Kirill Grigoryev @ SPIN2006 5
Test of the Medium-field RF-Transition Unit
0 . 0 E + 0 0
5 . 0 E - 0 8
1 . 0 E - 0 7
1 . 5 E - 0 7
2 . 0 E - 0 7
2 . 5 E - 0 7
3 . 0 E - 0 7
0 200 400 600 800 1000 1200 1400D2 current, A
Pre
ssur
e in
the
tar
get
cham
ber,
e-7
mba
r .
H beam OFF H beam ON, states 1 + 2 H beam ON, state 1 only
3.0
2.5
2.0
1.5
1.0
0.5
0.0
field strength in the D2 gap0 T 1.58 T
0 . 0 E + 0 0
5 . 0 E - 0 8
1 . 0 E - 0 7
1 . 5 E - 0 7
2 . 0 E - 0 7
2 . 5 E - 0 7
3 . 0 E - 0 7
0 200 400 600 800 1000 1200 1400D2 current, A
Pre
ssur
e in
the
tar
get
cham
ber,
e-7
mba
r .
H beam OFF H beam ON, states 1 + 2 H beam ON, state 1 only
3.0
2.5
2.0
1.5
1.0
0.5
0.0
field strength in the D2 gap0 T 1.58 T
No dependence of MFT on D2 field No dependence of MFT on D2 field Shielding ok Shielding ok
03.10.2006 Kirill Grigoryev @ SPIN2006 6
PIT at ANKE
Using of the ABS at ANKE
jet target with storage cell
An additional methods to improve COSY beam
Electron cooling Stacking at injection
Stochastic coolingBeam scraping
03.10.2006 Kirill Grigoryev @ SPIN2006 7
ABS-jet test with catcher
Without
ABS jet
With
ABS jet
Without catcher
4.0·10-9 3.0·10-7
With catcher
4.0·10-9 3.7·10-8
ABS beam catcher
~13cm~13cm
Measured pressures in the target chamber, mbarN
um
ber
of
even
ts
integral thickness ~ 1.5 . 1011 cm-2
ABS BeamABS Beam
COSY BeamCOSY Beam
03.10.2006 Kirill Grigoryev @ SPIN2006 8
Storage cell setup
COSYbeam
XY-table Frame with storage cell and aperture
Target chamber
Feeding tube: l = 120 mm, Ø = 10 mm
Extraction tube: l = 230 mm, Ø = 10 mm
Beam tube : l = 400 mm, 20x20 mm2
400mm400mm
COSYbeam
XY-table Frame with storage cell and aperture
Target chamber
Feeding tube: l = 120 mm, Ø = 10 mm
Extraction tube: l = 230 mm, Ø = 10 mm
Beam tube : l = 400 mm, 20x20 mm2
400mm400mm
03.10.2006 Kirill Grigoryev @ SPIN2006 9
Cooler Stacking with the Storage Cell
ΘANKE beamNumber of accelerated protons to 600 MeV
no cell empty cell ABS H–fed cell
0°electron cooling 1.4x1010 3.5x109
Stacking + electron cooling
2.6x1010 2.0x1010
9.2° 6.0x109 6.4x109
28 stacks with 2s electron cooling
acceleration to Tp=600 MeVafter 58s from cycle start
Stored particles in the ring = 6.4 · 109 protons
H target thickness = 2 · 1013 atoms/cm2
Average luminosity > 1029 cm-2s-1
&&
03.10.2006 Kirill Grigoryev @ SPIN2006 10
Stochastic cooling
Cooling off
Cooling on
Tp=831 MeV
• Length of the cycle = 10 min • Minimum energy for stochastic cooling is 831MeV
03.10.2006 Kirill Grigoryev @ SPIN2006 11
PIT commissioning
N2 in cell
Tp=831 MeV
H2 in cell
Tp=831 MeV
Cell feeding with Nitrogenhelps to obtain background
from interactionswith the cell wall
Clear spot of the events from the cell-target gas
pp→dπ+ reaction
03.10.2006 Kirill Grigoryev @ SPIN2006 12
Target polarization from nuclear reaction
Used HFS 1 and 2 (only MFT).WFT would provide higher polarization in state 3, but did not work.
Tp=831 MeV
Assuming both polarization P+ and P- were equal P = 0.44±0.03
Theoretically we expect P+=0.85 and P-=-0.27(-0.18) P = 0.56 (0.51)
– HFS1– HFS2
03.10.2006 Kirill Grigoryev @ SPIN2006 13
Future plans
ongoing – Teflon coating and new cell production
Autumn ’06 – studies of nuclear polarization of molecules from
recombined polarized H and D atoms
use of the ABS in the other project ( ISTC #1861 )
December ’06 – PIT reinstallation with Lamb-shift polarimeter at ANKE
January ’07 – First double polarized experiment: dp → (pp)n→→
see talk D. Chiladze
03.10.2006 Kirill Grigoryev @ SPIN2006 14
Do we have zero field crossings along the ABS axis?
-200
-100
0
100
200
300
400
500
0 20 40 60 80 100
Bx By Bz Btotal
B, G
l , cm
1. Determine the local Larmor precession frequency ωL
2. The angular velocity of the magnetic field ωB.
As long as the ratio R=ωL/ωB is large, the spin of the atom follows the field direction. no depolarizationno depolarization
due to zero crossingsdue to zero crossings
Magnetic field along ABS axis• ID2 = 563 A• ID1D3= 1294.84 A
Magnetic field scan with ANKE at 5.3º using a 3D Hallprobe (Gatchina):
1.0E+02
1.0E+03
1.0E+04
1.0E+05
1.0E+06
1.0E+07
1.0E+08
1.0E+09
1.0E+10
0 20 40 60 80 100
wl wb wl / wb l , cm