J. Lettry CERN AB-ATB 10 March 05 1
EURISOL targetry challengesEURISOL shall deliver beams of 3 orders of magnitude
higher intensity than 1999 yields.
• Design of “oven + heat-transport system” target containers dissipating a direct GeV p-beam dc-power of > 100 kW to produce spallation generated RIBs.
• Computational optimization of the wall material and target geometry of a chosen element from a “target vessel, transfer line & ion-source” system to improve the release efficiency.
• Improve ion-source efficiencies and beam purity.• Design high power density spallation n-sources (10 MW/l) • Design actinide targets intercepting efficiently the
neutrons generated by high power density n- sources.
J. Lettry CERN AB-ATB 10 March 05 2
Introduction to ISOL RIB facilitiesIsotope Separation On Line
• ISOLDE• TRIUMF
J. Lettry CERN AB-ATB 10 March 05 3
ISOLDE target handling.
Class A laboratoryΣIsotopes (Activity/LA) > 10’000
J. Lettry CERN AB-ATB 10 March 05 4
ISOL “Thick” targets
(1 GeV ~ 200 g/cm2)
Protons
+/- 8V500A
+/- 9V1000A
*
Pre-Separation, SeparationExtraction, beam optics
Ionisation
Molecular transportEffusion
DiffusionDiffusion
Nucl. reaction
Target material 5-200 g/cm2
“Oven - Radiator” (Ta,Mo,Nb, C …)
Ion-source & Transfer line
(Ta,Mo,Nb, C …)
J. Lettry CERN AB-ATB 10 March 05 5
ISOLDE Front-End Technical design
Faraday cup & QP triplet Section
Exchangeable Target and Ion-Source
coupling section
x-y Electrostatic steering+ z Movement
External alignment
Quick exchangeof spare parts
+60 kV
S. Marzari& ATB-IF
5×1019 p/y5 MGy/y
Strategy: 2 FE + 1spareProduction needs: 1 FE/3years“Minor” repair after 1 year of cooling
J. Lettry CERN AB-ATB 10 March 05 6
6 ≤ Z ≤ 92 Target materials
25 Elements,~ 40 compounds:
Oxides, CarbidesMolten metals, - saltsThin foils, Powders
Target thickness: 4-220 g/cm2
Cross section σ (Eproton)
0
20
40
60
80
100
C Al Si Ca Sc Ti V Mg Ge Sr Zr Nb Sn Te Ba La Ce Gd Ta W Ir Au Pb Th U
Spallation, Fragmentation & fission
Beam power for ISOL-RIB production:Liquids (1-2 kW), Solids (5 kW),
Ta, Nb, SiC (20-30 kW @ TRIUMF)
J. Lettry CERN AB-ATB 10 March 05 7
0
20
40
60
80
100
0 20 40 60 80 100 120 140 160
Neutrons
Z
181-Ta 1.0 GeVNat. & stable
Ta + 1 GeV p, CASCABLA, A. Junghans
1 GeV proton induced Spallation
J. Lettry CERN AB-ATB 10 March 05 8
Chemically selective RIB Ion-sources
Surface ion-source
Negative ion-sources
FEBIAD ion-sources
RILIS, Elements available 2004
ECR 1+
1 2H He
3 4 5 6 7 8 9 10Li Be B C N O F Ne
7.0%11 12 13 14 15 16 17 18
Na Mg Al Si P S Cl Ar9.8%
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
19.2% 0.8% 6.6% 4.9%37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe14.0% 8.8% 8.5%
55 56 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
87 88 104 105 106 107 108 109Fr Ra Ac
57 58 59 60 61 62 63 64 65 66 67 68 69 70 71La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
2.0% 12.5%89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lw
J. Lettry CERN AB-ATB 10 March 05 9
Ion-sources efficiencies
0
5
10
15
20
25
0 20 40 60 80 100Z
Ioni
zatio
n po
tent
ial
[eV
]
ECR ?NegativePlasmaSurface
0.1%
1.0%
10.0%
100.0%
0 4 8 12 16 20 24
Ionisation potential [4-25 eV]
Ioni
satio
n ef
ficie
ncy RILIS
ECR FEBIAD
W-surface
LaB6-surfaceKENIS
Electron Affinity [0-4 eV]
RILIS
J. Lettry CERN AB-ATB 10 March 05 10
Release efficiencyeffusion, diffusion
0.1
1
10
100
1000
10000
100000
1 10 100 1000 10000 100000
T delay + 1/2 collection [ms]
Cou
nt ra
te [H
z]
Data
Bg & Coll. Corr.
25Na (59.6s)UC-118 2100°C
32Na (13.5 ms)33Na (8.2 ms)
…..
J. Lettry CERN AB-ATB 10 March 05 11
0
20
40
60
80
100
0 20 40 60 80 100 120 140 160
neutrons
z
< 1s< 1 min< 1h< 1day< 1 week< 1 month< 1 year> 1 yNat. & stable
Half lives
J. Lettry CERN AB-ATB 10 March 05 12
0
20
40
60
80
100
0 20 40 60 80 100 120 140 160Neutrons
Z
ISOLDENat. & stable
ISOLDE yields: ~750 RIBs produced (1963-2004)
J. Lettry CERN AB-ATB 10 March 05 13
EURISOL -- EURISOL DS
• 4 years EU project published end 2003; • Conclusion: RIB yields enhancement
predicted (vs. 1999 data) by factors of 2 to 4 orders of magnitude !
• 2005 EURISOL-DS to address the remaining technological challenges
J. Lettry CERN AB-ATB 10 March 05 14
EURISOL target stations
• 3×100 kW direct irradiation• Fissile target surrounding a spallation n-source
– >100 kW Solid converters (RAL 800 kW operational)– 4 MW Hg-jet
J. Lettry CERN AB-ATB 10 March 05 15
Top view
3 × 100 kWTarget stations
Beam distribution
4 MWTarget station
Target handling
Experimental hall
~1 GeV p-driver
J. Lettry CERN AB-ATB 10 March 05 16
100 kw direct irradiation
• Target Materials: > 25– Thickness, Heat transport, dose rate– Diffusion and Effusion delays
• Chemical nature of the target: 6• Oven Materials: 4• Elements to be produced: > 70• Transfer line: 4
– Drift fields• Ion source: 5
– Stabilisation of the production (Std. eff., life time, reproduce on-line the best off-line results).
– Radiation Hardness.– Selectivity vs. isobars.
• Maintenance, vacuum vessel, pumps, radioactive Waste handling.
OneOneStandard
Front-end ??
100100Target and Ion-source systems
J. Lettry CERN AB-ATB 10 March 05 17
TEST casesTEST cases 100 kW direct• Targets
– Actinide target (carbide)• UC2+C, ThC2+C• W-converter, Moderator & Reflector
– Metal foil target (solid)• Ta, Nb
– Oxide powder of fiber • BeO + converter• Insulating materials low dE/dx• Low density
– Molten metal (Liquid)• Vapor condensation
• Ion-sources– Mono ECR– RILIS, Surface– FEBIAD
• Elements– He, Li, Be, Hg …
Spin off is expected on: - Similar target materials
- Elements from the same chemical group
44 Targets 44 Ion-sources11 Front-end
Synergy with β-beam
J. Lettry CERN AB-ATB 10 March 05 18
SiC Triumf
J. Lettry CERN AB-ATB 10 March 05 19
Mass separator
Confinement of radioactve gases
(cold trap)
Target stationChemically selective ion-source (RILIS)
Confinement of the activity, RIB-selection
J. Lettry CERN AB-ATB 10 March 05 20
Target plugs
J. Lettry CERN AB-ATB 10 March 05 21
Actinide target• Cylindrical, donut or C-shaped optimized
vs. n-flux … and target exchange.• Target material: Test of the release
properties of high density UC2 vs. UC2+C powder
• Thermal equilibrium issue: the target is kept at 2200ºC while its inner or close by placed Hg-n-spallation source Has to evacuate ~1 MW.
11 Target ?55 Ion-sources11 Front-end
Synergy with SNS, SPIRAL II and SPESCompetitive method: high flux reactors
235U-fission at MAAF
J. Lettry CERN AB-ATB 10 March 05 22
p- or n-induced fission
Fission probability
1.0E-04
1.0E-03
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1.0E+02
0 50 100 150 200
A [amu]
Fiss
ion
prob
abili
ty [
%]
238U, 1.4 GeV p,f (2.59 barn) CASCABLA
238U, 600 MeV p,f (2.25 barn) CASCABLA
235U, Thermal n,f ( 582 barn)
J. Lettry CERN AB-ATB 10 March 05 23
Spallation n-sources• Cooled Ta or W-rods• Hg stream or confined Hg-jet
ISOLDE n-spallation source: Ta(W)-rod mounted below
the UC target (before irradiation)
- Engineering study of the thermal hydraulics, fluid dynamics and construction materials of a window free liquid-metal converter.- Study of an innovative waste management in the liquid Hg-loop e.g. by means of Hg distillation.- Engineering design and construction of a functional Hg-loop.- Off-line testing and validation of the thermal hydraulics and fluid dynamics.- Detailed planning and proposal for subsequent in-beam test in collaboration with other Hg target users.- Engineering design of the entire target stationand its handling method
J. Lettry CERN AB-ATB 10 March 05 24
Cs-yields UC2-183
1E+0
1E+1
1E+2
1E+3
1E+4
1E+5
1E+6
1E+7
1E+8
1E+9
1E+10
132 134 136 138 140 142 144 146 148 150
Cs mass
Yiel
d (1
/C
)
0
20
40
60
80
100
ratio
[-]
p+ on UC-targetp+ on Ta-converterRatio
Spallation Fission
Kr, Xe and Cs yields, Ta-W converter
The yields of very n-rich isotopes obtained via neutron induced fission of Th or U
are close to those of high energy protons.Further developments:
Geometrical optimum and n-reflectors
0
2
4
6
8
10
135 140 145 150Xe mass [amu]
1GeV
1.4GeV
0
2
4
6
8
10
85 90 95 100Kr mass [amu]
Y (p
) / Y
(n)
UC2 + W-converter
J. Lettry CERN AB-ATB 10 March 05 25
Conclusion
• The EURISOL-DS-targetry group proposes: – 4 test cases to define the front-end of the
100 kW target stations (T3).– Investigation of a spallation n-source based
on Hg loop (4 MW) (T2) and cooled solids (<1 MW) (T4).
– Compare yields of high-density and powder of actinide carbides (T4).
• Decision on EU-funding of the EURISOL DS project in June 2004
J. Lettry CERN AB-ATB 10 March 05 26
0
4
8
12
16
CERN PSI LMU UCL CEA
Sta
ff FT
E
AvailableReq. Contr.
EU-funding 890 kEuros
CERN
PSI
LMU
UCLCEA
T3 – direct target
HR
Material
Travel
Total estimated Cost (k€): 2439Contribution from UE (k€): 890