Post on 11-Jan-2016
description
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
• Facility overview • Ion sources at COSY• R&D details
• Cs ionizer• Extraction • Actual investigations (ABS, LSP)
• Summary and outlook
Polarized H- and D- Beams at COSY/Jülich
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
The COSY Facility• 0.6 .. 3.65 GeV/c p and d
• polarized beams
• beam cooling
• internal and external detectors for the investigation of nuclear quark structure and dynamics, fundamental symmetries and e.g. exotic mesons, rare decays
COoler SYnchrotron
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
The COSY Injector
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Light Ions for COSY
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
0000 CsHCsHHILnI
vA
LII
Charge exchange reaction
H0(D0) + Cs0 H-(D-) + Cs+
The COSY Polarized Source
RF dischargeThermal ionizer
38 K1150 K550 K
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
The COSY Polarized Source
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Atomic Beam Source
Cesium Ionizer
and
Beam Line
The COSY Polarized Source (II)
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Cs Ionizer – Replacement of the Prototype
S. Lemaitre’s and R. Reckenfelderbäumer’s Ph.D. thesesNIM A 408, 345 (1998)
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Tungsten Ionizer
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Next Iterations
M. Eggert’s Ph.D. thesisNIM A 454, 514 (2000)
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Pulsed Version
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
• dc and pulsed operation (0.5- 3 Hz)
• 6 mA routinely @ 45keV – 25 ms 0.5 Hz
• up to 1500 hours continuous operation for COSY and experiments
• 3 sources for exchange
Development of Cs+ Sources
-4 kV
-5 kV
-6 kV
-7 kV
-7.5 kV
0
4
8
12
mA
Emitted Cs+
current
Emitted Cs+ current
5.5 mA
20 ms
55°C
60°C
65°C
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
A set of computer controlled wire scanners
• for Cs+/o diagnosis
• to judge the beam and the ionizer quality
• to optimize Cs+/o transmission
• space charge compensation by adding Argon
Focusing the Cesium Beam
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Field Gradient inside the Solenoid
1994
2005
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Beam Current vs. U and B
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Extraction and Deflection
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Improvement of Beam Extraction
H- Cs+, Cs0Mounting the extraction elements
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Focusing the Atomic (H, D) Beam
Monte-Carlo simulation
Integration over r, r’, spin and velocity
-20
0
20
Rad
ius
[mm
]
0.0 0.4 0.8 1.2 1.6Distance to 2nd hexapole [m]
0
5
10
15
20
25
Rad
ius
[mm
]
0.0 0.5 1.0 1.5Distance to 2nd hexapole [m]
60 %70 %80 %
90 %Solenoid
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Exchange of the EM hexapoles
EM diameter 220 mm
PM diameter 80 mm
220
mm
M. Altmeier’s and O. Felden’s Ph.D. thesesNIM A 626, 117 (1997)
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Neutral Beam Profile Scanner
Estimation of the atomic beam size and position by using the Cs scanner inside the atomic beam part and a compression tube
0,E+00
2,E+15
4,E+15
6,E+15
8,E+15
1,E+16
-20 -15 -10 -5 0 5 10 15 20
horizontal wire position [ mm ]
inte
ns
ity
[a
tom
s /
se
c ]
0,E+00
1,E+16
2,E+16
3,E+16
4,E+16
5,E+16
6,E+16
inte
gra
ted
sig
na
l
0,E+00
2,E+15
4,E+15
6,E+15
8,E+15
1,E+16
-20 -15 -10 -5 0 5 10 15 20
vertical wire position [ mm ]
inte
ns
ity
[ a
tom
s/
se
c ]
0,E+00
1,E+16
2,E+16
3,E+16
4,E+16
5,E+16
6,E+16
inte
gra
ted
sig
na
l
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
2 4 6 8 10 12 14 160
20
40
60
80
100
120
140
160
180
200
ato
mic
hyd
rog
en
be
am
de
nsi
ty(T
OF
- m
V)
number of molecules (rel. units)
T_n = 36 K T_n = 77 K
2 4 6 8 10 12 14 16
600
800
1000
1200
1400
1600
1800
2000
2200
2400
mo
st p
rob
ab
le v
elo
city
(m
/s)
number of molecules (rel. units)
T_n = 36 K T_n = 77 K
2 4 6 8 10 12 14 160
20
40
60
80
100
figu
re o
f me
rit
number of molecules (rel. units)
T_n = 36 K T_n = 77 K
Estimation of density and velocity
The density was measured with a TOF mass spectrometer.
Figure of merit = density / v²
(magnet acceptance ~ 1/T)
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Dissociator Development
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Dissociator Development
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Dissociator Development
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Improved Density with new Design
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Lambshift Polarimeter
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Lambshift Polarimeter
Ready for first beam!
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Summary: Intensity record for deuterons
unpolarized deuterons switching to polarized deuterons
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Summary: Intensity and polarization
Beam current at the source exit Polarization inside COSY
Data from Exp. EDDA
(pp – elastic scattering)
Pavg = (91.4 2.2 ) %
Institute for Nuclear Physics (IKP) r.gebel@fz-juelich.de
Ralf Gebel – PSTP 2007 – 10.-14.September 2007
Outlook
• Beam for the Lambshift Polarimeter
• Improved atomic beam stage for COSY Operation
Thank you! Thank you!
Acknowledgments: A.S. Belov (ABS, LSP...)R. Engels (LSP)