results with iscool a new radio frequency quadrupole cooler and buncher at isolde
DESCRIPTION
Results with ISCOOL a new Radio Frequency Quadrupole Cooler and Buncher at ISOLDE. P. Delahaye, H. Fr å nberg, AB-OP-PSB, ISCOOL, COLLAPS, ISOLDE collaboration. Where at ISOLDE. ISCOOL. Installation in pictures. INSTALLATION. Implementation of the RFQ into the ISOLDE vacuum system. - PowerPoint PPT PresentationTRANSCRIPT
ISOLDE WS 2007
Results with ISCOOL a new Radio Frequency
Quadrupole Cooler and Buncher at ISOLDE
P. Delahaye, H. Frånberg,
AB-OP-PSB, ISCOOL, COLLAPS, ISOLDE collaboration
ISOLDE WS 2007
ISCOOL
Where at ISOLDE
ISOLDE WS 2007
Installation in pictures
ISOLDE WS 2007
INSTALLATIONImplementation of the RFQ into the ISOLDE
vacuum system.Construction of HV platform and HV cage of
the RFQ. Standard controls in the working sets: QP
arrays for the RFQ and for the beam tuning after the cooler.– RF and gas still on LabVIEW.
ISOLDE WS 2007
OPERATION OF ISCOOL
• Set-up by the ISOLDE operators.
• Improved transmission past the switchyard Improved (faster and easier) set-up for the beam
to the experiments
ISOLDE WS 2007
Principle
RFV
Three elements:RF quadrupolar fieldRadial
confinement
DC potentialsExtracting ion in bunches or in continuous mode
Buffer gas Ion motion cooling
ISOLDE WS 2007
Transmissions
• Potentials along the axis
Transmission dependence on the emittance of the ISOLDE ion sources.ISOLDE on-line surface ion sources has smaller emittance than ISOLDE FEBIAD ion sources (<25 π·mm mrad). The off-line tests were performed with an ion source with ε = 35π mm mrad
80eV
5-2V/cm
~1E-2 mbar 4He10-2mbar l/s
EXTRACTIONINJECTION
50V (30V enough)
TRAPPING
0 20 40 60 80 100 120 1400
20
40
60
80
100
Mass
Tra
nsm
issi
on
on-line surface ionsourceon-line plasma ionsourceoff-line surface ionsource
ISOLDE WS 2007
Bunching mode
30-60 keV
80eV5-2V/cm
~1E-2 mbar 4He10-2mbar l/s EXTRACTIONINJECTION
50V (30V enough)
TRAPPING
ISOLDE WS 2007
Cooling time• TOF < 1ms from the
entrance to the exit of the RFQ– No losses for short
lived ions.• 1 passage is enough
to get a cold beam – as measured off-line,
and other labs as predicted by simulations for other systems
-200 0 200 400 600 800 1000 1200 1400 1600 1800-1
0
1
2
3
4
4.0x10-4
6.0x10-4
8.0x10-4
1.0x10-3
1.2x10-3
1.4x10-3
1.6x10-3
Bea
m g
ate
Time [s]
MC
P
ISOLDE WS 2007
Emittance measurements (off-line)~35p·mm·mrad 95% emittance
~2.2p·mm·mrad 95% emittance
• 10 x decrease of the beam emittance– The worst case scenario
at ISOLDE is the FEBIAD ion source with >25 p·mm·mrad emmittance.
• Injection efficiency into the cooler is depending on the beam emittance from the ISOLDE target and ion source unit.
ISOLDE WS 2007
0.00E+000 4.00E+008 8.00E+008 1.20E+009-2.00E+007
0.00E+000
2.00E+007
4.00E+007
6.00E+007
8.00E+007
1.00E+008
1.20E+008
1.40E+008
1.60E+008
Ext
ract
ed
ion
s
Injected ions
Space charge limits• Up to 108/s!! As
measured with FC (data under analysis with MCP)
0 1x109 2x109 3x109 4x109 5x109
0.0
2.0x107
4.0x107
6.0x107
8.0x107
1.0x108
1.2x108
1.4x108
Ext
ract
ed io
ns
Injected ions
39K, Collection time=10 ms–1 secExtraction time 150 us
85Rb
0.0 5.0x107 1.0x108 1.5x108 2.0x108 2.5x108
0.0
2.0x106
4.0x106
6.0x106
8.0x106
1.0x107
1.2x107
1.4x107
Ext
ract
ed io
ns
Injected ions
23Na
ISOLDE WS 2007
Bunch width
Depends on the space charge and cooling time
-40 -20 0 20 40 60 80 100 120 140
-8x10-3
-7x10-3
-6x10-3
-5x10-3
-4x10-3
-3x10-3
-2x10-3
-1x10-3
0
1x10-3
2x10-3
MC
P s
igna
l
Time [s]
10 ms 100 ms 1000 ms
Collection time=cooling time
ISOLDE WS 2007
Yield measurements• 26Na T1/2=1.07 s
• 48K T1/2=6.8 s
• Yields in continuous mode: – 26Na :1.2e6 at/uC– 48K: 2.2e4 at/uC
• Yields in bunched mode – analysis under progress
ISOLDE WS 2007
HOT SPOTS
0.5 µSv/h15 µSv/h
10 µSv/h
3 µSv/h
10 µSv/h
15 µSv/h
5 µSv/h5 µSv/h
0.5 µSv/h
Beam direction
ISOLDE WS 2007
Results• High transmission efficiencies• Easy beam tuning to experiments• Yield measurements continuous vs. bunched
mode• Losses due to trapping time (analysis in
progress • First measurements with radioactive isotopes
performed together with COLLAPS (see next talk)
ISOLDE WS 2007
ISOLDE HRS + Cooled beams
HRSIS
COO
L
ISOLDE WS 2007
OutlookUp to October 2007:
From Nov. 2007:
Next step:
Upgrade of HRS Mag 90:
EURISOL HIE Isolde:
ISOLDE WS 2007
Thanks to:• AB-OP-PSB-iso
team: Pascal, Erwin, Magnus, Emiliano and Tim.
• AB/ATB• AB/CO• AB/PO• AB/VAC
• SC/RP• ISOLDE
collaboration• COLLAPS
collaboration• ISCOOL
collaboration
ISOLDE WS 2007