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