Status Report of the LISOL Laser Ion Source

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Status Report of the LISOL Laser Ion Source

• Yu.Kudryavtsev, T.Cocolios, M.Facina, J.Gentens,
  M.Huyse, O.Ivanov, D.Pauwels, M.Sawicka, P.Van
  den Bergh, P.Van Duppen,
• Instituut voor Kern- en Stralingsfysika, K.U.
  Leuven,
• Celestijnenlaan 200 D, B-3001 Leuven, Belgium.

Yu.Kudryavtsev, SMI06, March 27-28, 2006
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Louvain-la-Neuve Radioactive Beam Facility
CYCLONE 110
CYCLONE 30
CYCLONE 44
LISOL
LASER ION SOURCE
LASERS
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Yu.Kudryavtsev, SMI06, March 27-28, 2006
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LISOL laser ion source
Time profiles of laser-ionized stable Ni-58 from
a filament
1994
Weak beam, 1nA, 1ms
We need to provide 1. Efficient laser
ionization 2. Survival of laser-produced ions in
a small volume around the exit hole
Strong beam, 1uA,20ms
Yu.Kudryavtsev, SMI06, March 27-28, 2006
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• LISOL Laser Ion Source is used since 1994 in
• Light ion-induced fusion evaporation reactions
  (Co,Ni,Mn)
• Heavy ion-induced fusion evaporation reactions
  (Rh,Ru,Ti)
• Proton-induced fission of U-238 (Ni,Co,Fe,Cu)
• Stopping of 185 MeV Ni beam in a gas cell
• Products from spontaneous fission Californium-252
  (Rh,Ru,Mo,Pd)

Yu.Kudryavtsev, SMI06, March 27-28, 2006
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Lay out of the gas cell and ion extraction
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Laser System
?2
Telescope
Excimer laser 2 LPX240, 200Hz, 15ns
Dye Laser 2
Synchron. Unit  
Energy meters
Telescope  
 
?1
Excimer laser 1 LPX240, 200Hz, 15ns

 
Dye Laser 1
SHG  
TOF SEM
Atomic beam
Reference Cell
Laser Ion Source at the LISOL front end
Tunable range 225 - 800 nm
15 m
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Laser System
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Two-step laser ionization schemes at LISOL
80 of all elements can be ionized by the LISOL
laser system in two steps The aim refractory
elements (thin target and fast extracion)
- found _at_ tested on-line
- found _at_ tested off-line
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Proton-induced fission of U-238
Z 29 28 27 26
Detection set-up
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Gamma spectroscopy of neutron-reach Fe isotopes
In June 2006 192 hours of beam time (protons 30
MeV)
Yu.Kudryavtsev, SMI06, March 27-28, 2006
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180
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Production of proton-reach nickel-54 isotope
In April 2006 168 hours of beam time (3He
45MeV) 54Fe(3He,3n) 54Ni
Test experiment in 2005
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Spontaneously fission of Californium-252
Life time 2.645 y 252Cf decays
96.9 to ? 3.1 to
fission fragments
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Cf-252 gas cell
Length 16 cm Inner diameter 7 cm Exit hole
diameter 0.5 mm Evacuation time (Ar) 0 - 10 s
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Gas cell for production of radioactive ions from
spontaneously fission Cf-252
Californium - 252 source Diameter 3
mm Activity 25 MBq, April 2004, (4 ? )
Transmission through degrader foil 33 Fission
fragments inside gas 2 E5 at/s
500 mbar Ar
a
a
Al foil, 6u
a



a
Movable holder


a


Plasma density 1e8 ion-el pairs/cm3 Recombinatio
n time 0.1 s

Cf-252
a
a
a
a
1. Survival of elements with different chemical
properties can be studied 2. Absolute efficiency
can be measured
Laser beams
SRIM calculation
Rh
500 mbar Ar
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Yu.Kudryavtsev, SMI06, March 27-28, 2006
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?-gated gamma spectrum of Rh-112 from Cf-252
source
Laser enhancement for Rh-112 isotopes from Cf-252
source
lasers - ON
560 keV
560 keV
Yield of 112Rh into gas 2.6 -gt 5000
at/s Laser ionized mass separated yield 250
at/s Efficiency 5 Selectivity 160
lasers - OFF
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Gamma spectroscopy using spontaneously fission
Cf-252 source
Spectroscopy 113Rh -116Rh Branching ratios,
life-times
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Yield of Cesium isotopes from Californium source
SPIG transport eff. 60 Mass separator eff.
90
500 mbar Ar
74 of Cs atoms stay in a single charge state
Ionization potential of Cesium - 3.9 eV
40
Distance to the exit hole-32 mm
32 mm
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Survival of Cesium Ions in Argon
Short-leaved isotope can be used to probe the
evacuation time inside the gas cell
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The problem to be solved Ion source efficiency
at high cyclotron beam current
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Laser ion source efficiency for heavy ion-induced
fusion evaporation reaction
40Ar 58Ni gt 98Pd gt Rh/Ru xp yn
95Rh
40Ar
Extraction efficiency as function of primary 58Ni
beam intensity
Ni beam
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Recombination of laser-produced ions at high beam
intensity
Time profile of extracted 40Ar ions
High plasma density in the laser ionization region
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Collection of electrons after the cyclotron pulse
2.9E10ions/s
Collection of electrons before laser ionization
increases ion signal
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