Page 1NANUF03 - Bucharest - September 7-12 2003 Optimisation of UCx targets for fission induced by fast neutrons or electrons. Optimisation of UCx targets

NANUF03 - Bucharest - September 7-12 2003 Page 1

Optimisation of UCx targets for fission Optimisation of UCx targets for fission induced by fast neutrons or electrons. induced by fast neutrons or electrons. Application for the SPIRAL 2 project

and the ALTO project

O. Bajeata), S. Essabaaa), JM. Gautiere), Y. Huguetb), F. Ibrahima), P. Jardinb), C. Laua),

N. Lecesneb), R. Leroyb), F.Nizery,c), M.Miread), F. Pellemoineb), A. Plukis c), D. Ridikasc)

MG. Saint-Laurentb), ACC Villarib)

a)Institut de Physique Nucleaire, 91406 Orsay, France b)GANIL, Bd H. Becquerel 14076 Caen cedex 5, France

c)DAPNIA, CEA Saclay, 91191 Gif sur Yvette, Franced)NIPNE, P.O. Box, MG-6, Bucarest, Romania

e)LPC, 6, boulevard du Maréchal Juin, 14050 Caen Cedex, France

Olivier BAJEAT


UCx Target by ISOLDE methodUCx Target by ISOLDE method

UO2 + 6C UC + 2C0 + 3C UC2 + 2C0 + 2C

The 3 steps of the manufacturing

- Mixing powder precursors

UO2 (~ 20 m) and C (44 m)

- Compressing the pellets

~ 8 tons/cm2

- Carburation

Heating under vacuum up to 2000 °C

Pellets diameter 14 mm


Experimental results with the two waysExperimental results with the two ways

Comparison with experimentsPerformed with the same

Conditions using deuterons20, 26, 50, 80 et 130 MeV

Photo-fission at CERN

a) electrons

b) neutrons


Experimental results with the two waysExperimental results with the two ways

Xe Kr

~ 4 ~ 4

Comparison of rare gas production with fast neutrons and Comparison of rare gas production with fast neutrons and photofissionphotofission

Ref.: F. Ibrahim et al. Photofission for the production of radioactive beams: experimental data from on-line measurement. European Physical Journal A 15, 2002, pp. 357-360


SPIRAL 2SPIRAL 2

SPIRAL 2 : fast neutrons

40 MeV deuterons / 5 mA on C converter => 1013 fissions/s

Technical studies in progress until end 2004

2008 at GANIL (Caen)


SPIRAL 2SPIRAL 2

ECS

LINACRFQ

D+

ions

ions

LASER

RFQbeam dump

Sépar. spectro HR

N+

identif.CO-CSS1

LIRAT

Sépar.

extension LINAC

physique avec ions

physique avec neutronsq/a = 1/6

q/a = 1/3

D+


SPIRAL 2 project: the target-ion source system SPIRAL 2 project: the target-ion source system

0,2m

1,4 m1m

0,75m

0,32m

2,25m

Primary beam Secondary beam


SPIRAL 2: the FICNER codeSPIRAL 2: the FICNER code

Angular distribution of neutronswhith a 40 MeV deuteron beam onto a C converter

0,00E+00

5,00E+13

1,00E+14

1,50E+14

2,00E+14

2,50E+14

3,00E+14

0 5 10 15 20 25 30 35 40 45 50

angle in degres

nb o

f neu

tron

s pe

r st

érad

ian

per

mA

mean = 1.25 barns

Ref.: M. Mirea et al. Modeling a neutron rich nuclei source. European Physical Journal A 11, 2001, pp. 59-78

ddxdydpyxzA

Nfbeam

)(.sin),,,(1

.238

N.

25.12 )1.141()(

P

1 d --> 0.02 n


SPIRAL 2: the target sizeSPIRAL 2: the target size

UCx targets production apparent density = 1,87 g U/cm3;

beam 10*40, distance entrance conv./target = 40

0,00E+00

1,00E+13

2,00E+13

3,00E+13

4,00E+13

5,00E+13

0 50 100 150 200

length in en mm

nb o

f fis

sion

s/s diam, 50

diam, 65

diam, 75

diam, 100

Effect of the distance converter-target on the productionPellets diam. 60 mm thick. 1 mm space : 0,3 mm (apparent density = 1,87 g U/cm3)

0,00E+00

5,00E+12

1,00E+13

1,50E+13

2,00E+13

2,50E+13

3,00E+13

3,50E+13

0 20 40 60 80 100

distance between the end of the converter and the front of the target in mm

nb

of

fis

sio

ns

/s p

er

5 m

A

L=50 mm

L=100 mm

L=150 mm

Distance converter-target

Diameter and length


SPIRAL 2: the target shapeSPIRAL 2: the target shape

What about a conical shape ?

1.7 1013 f/s 1.6 1013 f/s 1.6 1013 f/s


SPIRAL 2: two possible targetsSPIRAL 2: two possible targets

Target 2Target 2

Target 1


194 MeV per fission

300 W for 1013 fissions/s

SPIRAL 2: thermal aspectSPIRAL 2: thermal aspect


SPIRAL 2: the ovenSPIRAL 2: the oven

graphite container

reflectors

support

Electrical connections

oven

insulators

Cooled chamber


ALTOALTO

ALTO : photofission

50 MeV electrons / 10 µA => 1011 fissions/s

under construction

operational in 2005 at IPN Orsay


Photofission: the FICEL codePhotofission: the FICEL code

Electrons slowing down

Photon productionfolding angular electron spread

and bremsstrhalung differential cross section

lungbremsstrhacollision dx

dE

dx

dE

dx

dE

ddE

dEE f

e

2

,,

dEddE

dEp

ddE

dExF

eE

E

fe

t

22

)(),,(

F de teta

Ref.: M. Mirea et al. Exploratory analysis of a neutron-rich nuclei source based on photo-fission Nuclear Instruments and Methods in Physics Research B 201, 2003, pp. 433-448

θ


ALTO: the FICEL codeALTO: the FICEL code

angular distribution of photons 11-17 MeV produced at different depth in an UCx target

0

0,5

1

1,5

2

2,5

0 5 10 15 20 25 30

angle in degres

nb

of

ph

oto

ns

/sr/

cm/e

-

x=2 mm

x=4 mm

x=6 mm

x=10 mm

Photon production


Photofission: the FICEL codePhotofission: the FICEL code

)1)((

)(

)().().()( )()( ZEzE

z

eENE

EdzeENEzNf

Ex

dEdxdzNftotalNf,,

)()(

θ

gamma attenuation in uranium

0,04

0,05

0,06

0,07

0,08

0,09

0,1

0 10 20 30 40 50

gamma energy (MeV)

mu

in c

m2/

g

)(E )(Efission cross section

0

0,05

0,1

0,15

0,2

0 10 20 30 40

E gamma in MeV

fissi

on c

ross

sec

tion

in

barn

Geant dipolar resonance


ALTO: the target productionALTO: the target production

Production of UCx target by photofissiondiameter 14 mm

0,0E+00

5,0E+10

1,0E+11

1,5E+11

2,0E+11

0 5 10 15 20

length in cm

nb

of

fiss

ion

s/s

for

10

µA

density 1,8

density 2,4

density 3,6

density 11


ALTO: the shape of the targetALTO: the shape of the target


ALTO: energy depositionALTO: energy deposition

Energie deposition in a UCx target diameter 14 mm

by 50 MeV electron beam without converter

0

1

2

3

4

5

6

7

8

9

10

0 1 2 3 4 5 6 7 8 9 10

depth in cm

dE

/dz

in M

eV

/cm

350 watt in the target

QQQ coll


ALTO: target with converterALTO: target with converter

)arg()( etctNfconvNfNf

)arg()arg()( etteQettQconvQQ coll

target production with converterUCx target diam.14 length 100; converter tungsten in touch

irradiated by 50 MeV electron beam

0,0E+00

2,0E+09

4,0E+09

6,0E+09

8,0E+09

1,0E+10

1,2E+10

1,4E+10

whithoutconv

1 mm 2 mm 4 mm 5 mm 7 mm 8 mm

converter thickness

Nb

of

fis

sio

ns

pe

r m

icro

co

ulo

mb

Nf target

Nf conv.


Release times (SPIRAL 2 and ALTO)Release times (SPIRAL 2 and ALTO)

MCNPX model for effusion study

• exact geometry description• Ec = 3/2 kT , T=2000°C

• source with cosine distribution on the surface


Release time (SPIRAL 2 and ALTO)Release time (SPIRAL 2 and ALTO)

Which space between pellets ? (Preliminary results)

--> Large space isn’t necessary


Accélérateur Linéaire auprès du Tandem d’Orsay

ALTO:ALTO: Accélérateur Linéaire Auprès Accélérateur Linéaire Auprès du Tandem du Tandem d’Orsayd’Orsay

Section

Beam stop

Target / ion source

PARRNe Separator

Experiments with electrons

Klystron


ALTO: specificationsALTO: specifications

50 MeV / 10 µA electron beam connected to the PARRNE 2 set up (used with 25 MeV / 1 µA deuton)

fission yields × 100

5 photofission experiments of 3 weeks of irradiation per year

Industrial applications

Exploitation from 2005

Budget: about 1M €Accelerating section from CERN (LEP injector)

RF equipment from LAL (Orsay)


ALTO: implantationALTO: implantation

Séparateur

Linac 50 MeV

Cible UCx


ALTOALTO

Accelerating section (from CERN)

Target / ion sourceQuads

Buncher


ALTO: characteristicsALTO: characteristics

Beam stopper

Accelerating section

Beamstopper

E-gun

Pre-buncherBuncher

screen

MI

UMA

Beam profiler

WCM

Magnet

PARRNe target

Frequency : 2,99855 GHz Repetition rate: 100 Hz max

Energy : 50 MeV max Impulsion current duration: 2ns to 2µs

Mean current max : 10 µA Maximum emittance: 6 mm.mrad at 50 MeV

Modulator 3GHz

gun

beam

10 ps

333 ps

2 ns to 4 µs

10 ms to 40 ms (100 Hz to 25 Hz)4,5 µs

< 70 mA

< 10 µA mean50 mA

1,8 A

0 to 1 A

0 to 10 A


ALTO: the target-ion sourceALTO: the target-ion source

Ion sources: MK5, surface ionisation, laser...


ALTO: other applicationsALTO: other applications

Biochemistry

Industrial applications

Biochemistry under ionizing radiation

Irradiation of proteins

Study of DNA under radiation

Study of electronic componentsunder irradiation

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Page 1NANUF03 - Bucharest - September 7-12 2003 Optimisation of UCx targets for fission induced by fast neutrons or electrons. Optimisation of UCx targets