status report of the lisol laser ion source yu.kudryavtsev, t.cocolios, m.facina, j.gentens,...
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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 1/24
CYCLONE 30CYCLONE 110
CYCLONE 44
LISOL
LASERS
Louvain-la-Neuve Radioactive Beam FacilityLouvain-la-Neuve Radioactive Beam Facility
LASER ION SOURCE
Yu.Kudryavtsev, SMI06, March 27-28, 2006 2/24
LISOL laser ion source
Energy (eV)
0
4
laser
+ ++
separator
primarybeam
SPIG
gas cell
Ar
target
3-10mg/cm2
40 kV
Time profiles of laser-ionized stable
Ni-58 from a filament
~1994
We need to provide:
1. Efficient laser ionization
2. Survival of laser-produced ions in a small volume around the exit hole
Weak beam, 1nA, 1ms
Strong beam, 1uA,20ms
Yu.Kudryavtsev, SMI06, March 27-28, 2006 3/24
Yu.Kudryavtsev, SMI06, March 27-28, 2006
LISOL Laser Ion Source is used since 1994 in
1. Light ion-induced fusion evaporation reactions (Co,Ni,Mn)
2. Heavy ion-induced fusion evaporation reactions (Rh,Ru,Ti)
3. Proton-induced fission of U-238 (Ni,Co,Fe,Cu)
4. Stopping of 185 MeV Ni beam in a gas cell
5. Products from spontaneous fission Californium-252 (Rh,Ru,Mo,Pd)
4/24
Lay out of the gas cell and ion extraction
filament
Fusion cell
Fission cell
Yu.Kudryavtsev, SMI06, March 27-28, 2006 5/24
500mbar Ar
1e-5mbar
1e-2 mbar
Dye Laser 2
Dye Laser 1
SHG
Synchron. Unit
Telescope
Telescope
Laser Ion Source at the LISOL front end
Reference Cell
Energy meters
15 m
1
2
TOF SEM
Laser System
Excimer laser 1
LPX240, 200Hz, 15ns
Excimer laser 2
LPX240, 200Hz, 15ns
Tunable range
225 - 800 nm
Yu.Kudryavtsev, SMI06, March 27-28, 2006 6/24
Atomic beam
Autoionizing stateEnergy (eV)
0
4
I.P.
Yu.Kudryavtsev, SMI06, March 27-28, 2006
Laser System
Yu.Kudryavtsev, SMI06, March 27-28, 2006
Excimer lasers
Dye lasers
SHG
Reference cell
towards LIS
7/24
Two-step laser ionization schemes
at LISOL
- found @ tested on-line
- found @ tested off-line
Yu.Kudryavtsev, SMI06, March 27-28, 2006
80% of all elements can be ionized by the LISOL laser system in two steps
The aim – refractory elements (thin target and fast extracion)
8/24
Yu.Kudryavtsev, SMI06, March 27-28, 2006
Calculated fission cross section
1.00E-06
1.00E-05
1.00E-04
1.00E-03
1.00E-02
1.00E-01
1.00E+00
60 62 64 66 68 70 72 74 76 78mass number
cros
s se
ctio
n [m
b] Fe
Co
Ni
p oly eth y len + b o rax
L ea d b rick s
C u + Z n
beam
im p lan ta tion tap e
p lastic d etectorsβ
MINIBALL
MINIBALL
DETECTOR
DETECTOR
γ γ
Detection set-up
9/24
Z
29
28
27
26
Proton-induced fission of U-238 Proton-induced fission of U-238
- Studied isotopes
- Isotopes measured in 2005
Yu.Kudryavtsev, SMI06, March 27-28, 2006
66Fe176 keV
66Fe807 keV
66Fe881 keV
6 6 F e9 1 8 k eV
66Fe930 keV
66Fe471 keV
66C o1246 keV
66C o1425 keV
66Fe1022 keV
66Fe176 keV
66Fe807 keV
66Fe881 keV
6 6 F e9 1 8 k eV
66Fe930 keV
66Fe471 keV
66C o1246 keV
66C o1425 keV
66Fe1022 keV
F e ß -g a te d sp e c tr a O n (r e d )/O ff (b lu e ) -r e so n a n c e 66
6 7 F e1 8 9
6 7 F e1 2 5 1 k e V
67Fe2054 keV
67Fe2080 keV
67Fe2087 keV6 7 F e
1 8 9 k e V
k e V6 7 C o
6 9 4
6 7 F e1 2 5 1 k e V
67Fe2054 keV
67Fe2080 keV
67Fe2087 keV
F e ß -g a te d sp e c tr a O n (r e d )/O ff(b lu e )-re so n a n c e 6 7
p oly eth y len + b o rax
L ea d b rick s
C u + Z n
beam
im p lan ta tion tap e
p lastic d etectorsβ
MINIBALL
MINIBALL
DETECTOR
DETECTOR
γ γ
Gamma spectroscopy of neutron-reach Fe isotopes
In June 2006 – 192 hours of beam time (protons 30 MeV)
10/24
Yu.Kudryavtsev, SMI06, March 27-28, 2006
Isospin symmetry test
54Fe(3He,3n) 54NiN=Z
Accurate comparison of Gamow -Teller transitions for A=46, 50 and 54 in beta decay and in (3He,t) reactions
11/24
180
Yu.Kudryavtsev, SMI06, March 27-28, 2006
I937=250(35), Pk/B = 2.3
922 keV:411+511
keV
Half-life fit:
Beam ON Beam OFF
T1/2 = 109 (13) ms
I937=177(16), Pk/B = 11.3
P = 12 at/C
P = 17 at/C
Production of proton-reach nickel-54 isotope
3He2+
In April 2006 – 168 hours of beam time (3He 45MeV)
54Fe(3He,3n) 54NiTest experiment in 2005
12/24
Yu.Kudryavtsev, SMI06, March 27-28, 2006
Spontaneously fission of Californium-252
0
0.5
1
1.5
2
2.5
3
3.5
4
80 90 100 110 120 130 140 150 160
Mass, a.u.
Yie
ld,
%
34Se
35Br
36Kr
37Rb
38Sr
39Y
40 Zr
41 NB
42 Mo
43 Tc
44 Ru
45 Rh
46 Pd
47 Ag
48 Cd
49 In
50 Sn
51Sb
52Te
53I
54Xe
55Cs
56Ba
57La
58Ce
59Pr
60Nd
61Pm
Independent Yields of Spontaneous Fission for Cf-252
105 MeV 85 MeV
112Rh
Life time – 2.645 y252Cf decays: 96.9% to 3.1% to fission fragments
13/24
Yu.Kudryavtsev, SMI06, March 27-28, 2006
Cf-252 gas cell
Exit hole
Gas in
Water cooling
Filament
Laser beams
Heating
Length – 16 cmInner diameter – 7 cmExit hole diameter – 0.5 mmEvacuation time (Ar) – 0 - 10 s
14/24
Yu.Kudryavtsev, SMI06, March 27-28, 2006
Gas cell for production of radioactive ions from spontaneously fission Cf-252
Californium - 252 source:
Diameter – 3 mmActivity – 25 MBq, April 2004, (4 ) Transmission through degrader foil – 33%Fission fragments inside gas – 2 E5 at/s
Plasma density – 1e8 ion-el pairs/cm3
Recombination time – 0.1 s
500 mbar Ar
Laser beams
Cf-252
Movable holder
Al foil, 6u+
+
++
+
+
αα
α
α
αα
α
α
α
+ +
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.00
100
200
300
400
Distance from Cf source, cm
CsRh
-3
-2
-1
0
1
2
3
-3 -2 -1 0 1 2 3
Y, cm
Z, c
m
Rh
SRIM calculation
15/24
1. Survival of elements with different chemical properties can be studied
2. Absolute efficiency can be measured
500 mbar Ar
Yu.Kudryavtsev, SMI06, March 27-28, 2006
-gated gamma spectrum of Rh-112 from Cf-252 source
0.1
1
10
100
1000
0 20 40 60 80 100
distance (exit hole-Cf252), mm
pro
du
cti
on
Rh
-112m
, at/
s
lasers-ONlasers-OFF
Laser enhancement for Rh-112 isotopes from Cf-252 source
0
5
10
15
20
25
30
35
40
0 200 400 600 800 1000 1200
energy, keV
cou
nts
/ch
ann
el
0
100
200
300
400
500
600
0 200 400 600 800 1000 1200
energy, keV
cou
nts
/ch
ann
el
lasers - ON
lasers - OFF
560 keV
560 keV
252Cf
Ar- 500mbar
52 mm
Yield of 112Rh into gas – 2.6% -> 5000 at/sLaser ionized mass separated yield – 250 at/sEfficiency – 5 %Selectivity: – 160
16/24
Yu.Kudryavtsev, SMI06, March 27-28, 2006
Gamma spectroscopy using spontaneously fission Cf-252 source
114Rh
Lasers - ON
Lasers - OFF
10
100
1000
10000
105 110 115 120
Mass, A.U.
Calcu
lated
yield
, at/s
42 Mo
43 Tc
44 Ru
45 Rh
46 Pd
47 Ag
48 Cd
Spectroscopy 113Rh -116Rh
Branching ratios, life-times
17/24
252Cf
Ar- 500mbar
52 mm
Yu.Kudryavtsev, SMI06, March 27-28, 2006
1,0E+01
1,0E+02
1,0E+03
1,0E+04
137 138 139 140 141 142 143 144 145 146
Cesium isotope, A.U.
Yie
ld o
f ce
siu
m is
oto
pe,
ato
ms/
s Fed into Ar gas
Measured after mass-separation
Efficiency, %
Yield of Cesium isotopes from Californium source
40%
500 mbar Ar
SPIG transport eff. – 60%
Mass separator eff. – 90%
74% of Cs atoms stay in a single charge state
Ionization potential of Cesium - 3.9 eV
Distance to the exit hole-32 mm
252Cf
Ar- 500mbar
32 mm
18/24
Yu.Kudryavtsev, SMI06, March 27-28, 2006
0.01
0.1
1
10
0 20 40 60 80 100 120
Distance exit hole - Cf-252 source, mm
Nor
mal
ized
yie
ld o
f Cs-
140
and
Cs-
142
142Cs T1/2=1,7s
140Cs T1/2= 64s
Life-time corrected on an evacuation time inside the gas cell
Survival of Cesium Ions in Argon
Short-leaved isotope can be used to probe the evacuation time
inside the gas cell
252Cf
Ar- 500mbar
Distance
19/24
Yu.Kudryavtsev, SMI06, March 27-28, 2006
The problem to be solved:Ion source efficiency at high cyclotron beam current
20/24
Yu.Kudryavtsev, SMI06, March 27-28, 2006
10-1 100 101 102 103 104 105 106 107 108 109 1010 1011
10-8
10-7
10-6
1x10-5
1x10-4
10-3
10-2
10-1
100
Lasers off
40Ar
58Ni
Eff
icie
ncy
Cyclotron beam current (pps)
58Ni
Lasers onlasersgas
Laser Ion Source Efficiency for Rh-95
0%
2%
4%
6%
8%
10%
12%
14%
16%
18%
20%
1.0E+09 1.0E+10 1.0E+11 1.0E+12
I cyclo [part/sec]
LIS
Eff
icie
ncy
[%
]
Laser ion source efficiency for heavy ion-induced fusion evaporation reaction
Extraction efficiency as function of primary 58Ni beam intensity
40Ar + 58Ni => 98Pd* => Rh/Ru + xp yn
95Rh
Ni beam
40Ar
21/24
Lasers -offgas
58Ni beam
Recombination of laser-produced ions at high beam intensity
Yu.Kudryavtsev, SMI06, March 27-28, 2006
Time profile of extracted 40Ar ions
High plasma density in the laser ionization region
22/24
2.9E10ions/s
Lasersgas
58Ni beam
Collector plate
Collection of electrons after the cyclotron pulse
Yu.Kudryavtsev, SMI06, March 27-28, 2006 23/24
Collection of electrons before laser ionization increases ion signal
Laser beams
gas
Target
Stopping volume
Ionization volume
Cyclotron beam
Separation of stopping and ionization volumes
Yu.Kudryavtsev, SMI06, March 27-28, 2006 24/24
Evacuation time inside the cell
0,01
0,1
1
10
100
0 1 2 3 4 5 6 7 8 9 10 11 12
Distance from the exit hole, cm
Ev
ac
ua
tio
n t
ime
, s
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