NANUF03 - Bucharest - September 7-12 2003 Page 1 Optimisation of UCx targets Optimisation of UCx targets for fission induced by fast for fission induced by fast neutrons or electrons. neutrons or electrons. Application for the SPIRAL 2 project and the ALTO project O. Bajeat a) , S. Essabaa a) , JM. Gautier e) , Y. Huguet b) , F. Ibrahim a) , P. Jardin b) , C. Lau a) , N. Lecesne b) , R. Leroy b) , F.Nizery, c) , M.Mirea d) , F. Pellemoine b) , A. Plukis c) , D. Ridikas c) MG. Saint-Laurent b) , ACC Villari b) 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, France d) NIPNE, P.O. Box, MG-6, Bucarest, Romania e) LPC, 6, boulevard du Maréchal Juin, 14050 Caen Cedex, France Olivier BAJEAT
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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
NANUF03 - Bucharest - September 7-12 2003 Page 2
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
NANUF03 - Bucharest - September 7-12 2003 Page 3
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
NANUF03 - Bucharest - September 7-12 2003 Page 4
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
NANUF03 - Bucharest - September 7-12 2003 Page 5
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)
NANUF03 - Bucharest - September 7-12 2003 Page 6
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+
NANUF03 - Bucharest - September 7-12 2003 Page 7
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
NANUF03 - Bucharest - September 7-12 2003 Page 8
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
NANUF03 - Bucharest - September 7-12 2003 Page 9
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
NANUF03 - Bucharest - September 7-12 2003 Page 10
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
NANUF03 - Bucharest - September 7-12 2003 Page 11
SPIRAL 2: two possible targetsSPIRAL 2: two possible targets
Target 2Target 2
Target 1
NANUF03 - Bucharest - September 7-12 2003 Page 12
194 MeV per fission
300 W for 1013 fissions/s
SPIRAL 2: thermal aspectSPIRAL 2: thermal aspect
NANUF03 - Bucharest - September 7-12 2003 Page 13
SPIRAL 2: the ovenSPIRAL 2: the oven
graphite container
reflectors
support
Electrical connections
oven
insulators
Cooled chamber
NANUF03 - Bucharest - September 7-12 2003 Page 14
ALTOALTO
ALTO : photofission
50 MeV electrons / 10 µA => 1011 fissions/s
under construction
operational in 2005 at IPN Orsay
NANUF03 - Bucharest - September 7-12 2003 Page 15
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
NANUF03 - Bucharest - September 7-12 2003 Page 16
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
NANUF03 - Bucharest - September 7-12 2003 Page 17
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
NANUF03 - Bucharest - September 7-12 2003 Page 18
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
NANUF03 - Bucharest - September 7-12 2003 Page 19
ALTO: the shape of the targetALTO: the shape of the target
NANUF03 - Bucharest - September 7-12 2003 Page 20
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
NANUF03 - Bucharest - September 7-12 2003 Page 21
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.
NANUF03 - Bucharest - September 7-12 2003 Page 22
Release times (SPIRAL 2 and ALTO)Release times (SPIRAL 2 and ALTO)