M
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NEW APPLICATIONS OF
MLJCl—S^FP
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Proceedings of the International Workshop on the
NEW APPLICATIONS OF
Bucharest, Romania 7-12 September 2003
editors
A. C. Mueller
Institut de Physique Nucleaire, France
M. Mirea
National Institute for
Physics
and Nuclear Engineering,
Romania
L. Tassan-Got
Institut de Physique Nucleaire, France
\[p
World
Scientific
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NEW APPLICATIONS OF NUCLEAR FISSION
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PREFACE
This volume contains the lectures and contributions presented at the
International Workshop "New Applications of Nuclear Fission"
(NANUF03), held at Bucharest, in Romania, from 7 September to 12
September 2003.
NANUF03 is the 4
th
international meeting in a series organized by
the European Commission Center of Excellence IDRANAP (Inter-
Disciplinary Research and Applications Based on Nuclear and Atomic
Physics) from the "Horia Hulubei" National Institute for Physics and
Nuclear Engineering (IFIN-HH). The European Commission, under
contract ICA1-CT-2000-70023, generously sponsored this meeting. The
workshop topics covered new experimental and theoretical studies
focused on the modern developments of nuclear fission aiming at
various applications in a wide range of fields. It was an occasion to bring
together scientists working in different fields related to nuclear fission in
order to disseminate experience and knowledge in the benefit of the
community.
The main topics of the workshop were: radioactive beam facilities
based on nuclear fission; nuclear waste transmutations and the future
accelerator driven systems; fission and spallation nuclear data and
modeling;
experimental and theoretical advances in the study of nuclear
fission;
fusion reactions and decay modes of superheavy nuclei; stability
against fission and many body systems and superasymmetric and
multicluster fission. A few contributions presented by very young

researchers emerging from connected domains were also accepted.
The atmosphere during the workshop was stimulating due to the
scientific level of the excellent lectures and the interesting contributions,
offering an excellent frame for discussions and raising new suggestions
and ideas.
The opening address was given by Dr. E. Dragulescu, General
Director of the National Institute for Physics and Nuclear Engineering,
and the IDRANAP European Center of Excellence was presented by Dr.
F. Buzatu, the Scientific Director.
The meeting took benefits from the presence of Dr. L. Biro, Minister
Secretary of State with Nuclear Safety, who presented a documented
image of the nuclear energy in Romania and emphasized the
importance of a durable development based on nuclear power plants.
Prof. A.C. Mueller illustrated the importance of international
VII
VIM
collaborations in the context offered by the 6 European Framework
Program and contributed to enhance the synergies within Romanian
researchers.
Special thanks are addressed to Prof. Yu.P. Gangrsky who
presented the concluding remarks in an outstanding manner.
We also thank to the International Advisory Committee consisting of
Y. Abe (Kyoto), F. Buzatu (Bucharest), R. Casten (Yale), M. Ciocanescu
(Pitesti), E. Dragulescu (Bucharest), C. Gheorghiu (Pitesti), W. Greiner
(Frankfurt am Main), J.H. Hamilton (Nashville), S. Hofmann
(Darmstadt), M.G. Itkis (Dubna), G. Muenzenberg (Darmstadt), Y.
Nagame (Tokai), W. von Oertzen (Berlin), Yu.Ts. Oganessian (Dubna),
D.N. Poenaru (Bucharest), A.V. Ramayya (Nashville), W. Scheid
(Giessen), K H. Schmidt (Darmstadt) and P. Schuck (Orsay).
The scientific secretary, Dr. Amalia Pop, and the technical secretary,

Mrs.
Alia Orascu, have done an extremely valuable and complex activity
for the preparation of the meeting and managed difficult matters during
the workshop efficiently, contributing essentially to the success.
We want to thank Mr. E. Pauna, Mr. A. Sokolov and Mr. G. Chisner
for their technical assistance.
A special acknowledgement is dedicated to Mr. M. Duma and Mrs.
Cristina Aiftimiei for their activity concerning the web design.
A.C.
Mueller
M. Mirea
CONTENTS
Preface vii
Fission Approach to Heavy Particle Radioactivities 1
D.N. Poenaru. R.A. Gherghescu and
W.
Greiner
MYRRHA, a Multipurpose European ADS for R&D 9
H.A. Abderrahim
Fusion-fission Dynamics and Synthesis of the Superheavy 14
Elements
Y.Abe
Quasifission of the Dinuclear System 25
G.G. Adamian, N.V. Antonenko and
W.
Scheid
Microscopic Optical Potential for Nuclear Transmutation, 31
Fusion Reactors and ADS Projects
M. Avrigeanu,
V.

Avrigeanu, M. Duma, W. von Oertzen
and
A.
Plompen
Identification of Excited
10
Be Clusters Born in Ternary Fission 41
of
262
Cf
A.
V.
Daniel.
G.M. Ter-Akopian, G.S. Popeko,
A.S.
Fomichev,
A.M. Rodin, Yu.
Ts.
Oganessian,
J.H. Hamilton, A.V. Ramayya, J. Kormicki, J.K. Hwang,
D. Fong, P. Gore, J.D. Cole, M. Jandel, L Krupa,
J. Kliman, J.O. Rasmussen, A.O. Macchiavelli,
I.Y. Lee, S C. Wu, M.A. Stoyerand
R.
Donangelo
Production of Photofission Fragments and Study of their 48
Nuclear Structure
Yu. P. Gangrsky and
Yu.
E. Penionzhkevich

Variation of Charge Density in Fusion Reactions 54
R.A. Gherghescu, D.N. Poenaru and
W.
Greiner
IX
X
Parent Di-Nuclear Quasimolecular States as Exotic Resonant 60
States
N. Grama, C. Grama and
I.
Zamfirescu
Fission Investigations and Evaluation Activities at IRMM 67
F J.
Hambsch. S. Oberstedt, G. Vladuca and
A.
Tudora
Investigation of GeV Proton-Induced Spallation Reactions 75
D.
Hilscher.
C M. Herbach, U. Jahnke, V.G. Tishchenko,
J. Galin, B.
Lott,
A. Letourneau, A. Peghaire, D. Filges,
F. Goldenbaum, K.
Nunighoff,
H. Schaal, G. Sterzenbach,
M.
Wohlmuther,
L Pienkowski, W.U. Schroder and
J.

Joke
Evidence for Transient Effects in Fission 82
B. Jurado. K H. Schmidt, C. Schmitt, A. Kelic, J. Benlliure
andA.R. Junghans
Traps for Fission Product Ions at IGISOL 89
S.
Kopecky.
T.
Eronen, U.
Hager,
J. Hakala, J.
Huikari,
A.
Jokinen,
V.S.
Kolhinen, A. Nieminen, H. Penttila,
S. Rinta-Antila, J. Szerypo and
J.
Aysto
Triple-Humped Fission Barrier and Clusterization in the 95
Actinide Region
A.
Krasznahorkay. M. Csatlos, J. Gulyas, M. Hunyadi,
A.
Krasznahorkay
Jr.,
Z. Mate,
P.G.
Thirolf,
D. Habs,

Y.
Eisermann, G.
Graw,
R. Hertenberger, H.J.
Maier,
O. Schaile, H.F. Wirth,
T.
Faestermann, M.N. Harakeh,
M.
Heil,
F.
Kaeppeler and
R.
Reifarth
Microscopic Analysis of the a-Decay in Heavy and Superheavy 101
Nuclei
D.S. Delion, A. Sandulescu and
W.
Greiner
Searching for Critical Point Nuclei in Fission Products 110
N.
V.
Zamfir.
E.A. McCutchan and R.F Casten
Fission Barriers in the Quasi-Molecular Shape Path 118
G.
Rover.
C. Bonilla, K. Zbiri and
R.A.
Gherghescu

XI
Probing the
11
Li Halo Structure by Two-Neutron Interferometry 124
Experiments
M. Petrascu. A. Constantinescu, I. Cruceru, M. Giurgiu,
A.
Isbasescu, H. Petrascu, I. Tanihata,
T.
Kobayashi,
K. Morimoto, K.
Katori,
A. Ozawa, K. Yoshida,
T.
Suda
and
S.
Nishimura
Dissipation in a Wide Range of Mass-Asymmetries 132
M. Mirea
Physics with SPIRAL and SPIRAL 2 138
M. Lewitowicz
Two-Proton Radioactivity of
45
Fe 146
C. Borcea
Optimization of ISOL UC
X
Targets for Fission Induced by 155
Fast Neutrons or Electrons

O.
Bajeat.
S. Essabaa,
F.
Ibrahim, C. Lau,
Y.
Huguet,
P.
Jardin, N. Lecesne, R.
Leroy,
F.
Pellemoine,
M.G. Saint-Laurent, A.C.C.
Villari,
F.
Nizery,
A. Piukis,
D. Ridikas, J.M. Gautier and
M.
Mirea
The ALTO Project: A 50 MeV Electron Beam at IPN Orsay 160
O.
Bajeat.
J.
Arianer,
P.
Ausset, J.M.
Buhour,
J.N. Cayla,
M. Chabot,

F.
Clapier,
J.L. Coacolo, M. Ducourtieux,
S. Essabaa, H.
Lefort,
F.
Ibrahim, M. Kaminski,
J.C. Lescornet, J.
Lesrel,
A.
Said,
S. M'Garrech,
J. P. Prestel, B. Waastand
G.
Bienvenu
Sensibility of Isomeric Ratios and Excitation Functions to 162
Statistical Model Parameters for the (
4
'
68
He,n,3n)-Reactions
T.V.
Chuvilskaya. A.A. Shirokova
andM.
Herman
Fragment Mass Distribution of the
239
Pu(d,pf) Reaction via 164
the Superdeformed (3-vibrational Resonance
K. Nishio. H. Ikezoe,

Y.
Nagame, S. Mitsuoka, I. Nishinaka,
L Duan, K. Satou, M.
Asai,
H. Haba, K. Tsukada,
N. Shinohara and
S.
Ichikawa
XII
Fingerprints of Finite Size Effects in Nuclear Multifregimentation 166
Ad. R. Raduta andAI. H. Raduta
Systematics of the Alpha-Decay to Vibrational 2
+
States 170
S. Peltonen. J. Suhonen and
D.S.
Delion
Analysis of a Neutron-Rich Nuclei Source Based on Photo- 172
fission
M. Mirea. L. Groza, O.
Bajeat,
F
Clapier,
S. Essabaa,
F.
Ibrahim, A.C.
Mueller,
J. Proust, N. Pauwels and
S. Kandry-Rody
Numerical Code for Symmetric Two-Center Shell Model 174

P. Stoica
Deformed Open Quantum Systems 176
A.
Isar
Decommissioning the Research Nuclear Reactor VVR-S 178
Magurele-Bucharest: Analyze, Justification and Selection
of Decommissioning Strategy
M. Dragusin,
V.
Popa, A. Boicu, C. Tuca. I. lorga
and
C.
Mustata
K-Shell
Vacancy Production and Sharing in (0.2-1.75) MeV/u Fe, 181
Co + Cr Collisions
C. Ciortea, I. Piticu, D. Fluerasu. D.E. Dumitriu,
A.
Enulescu, MM.
GugiuandA.T.
Radu
Some Fission Yields for
235
U(n,f),
239
Pu(n,f),
238
U(n,f) 183
Reactions in ZE Neutron Spectrum
C. Garlea and

I.
Garlea
Recalibration of Some Sealed Fission Chambers—France in 185
MARK III, Mol, Belgium Facility
H.A. Abderahim, I. Garlea. C. Kelerman and
C.
Garlea
XIII
Muon Decay, a Possibility for Precise Measurements of Muon 190
Charge Ratio in the Low Energy Range (<
1
GeV/c)
B. Mitrica. A. Bercuci, I.M. Brancus, J. Wentz, M. Petcu,
H.
Rebel,
C. Aiftimiei, M. Duma and
G.
Toma
Research and Development Activities as Support for 193
Decommissioning of the Research Reactor VVR-S Magurele
M. Dragusin
Light Heavy-Ion Dissipative Collisions at Low Energy 195
A.
Pop. A. Andronic, I. Berceanu, M. Duma, D. Moisa,
M. Petrovici,
V.
Simion, G. Imme, G. Lanzano, A- Pagano,
G.
Raciti,
R. Coniglione, A. Del

Zoppo,
P.
Piatelli,
P. Sapienza, N. Colonna, G. d'Erasmo and
A.
Pantaleo
Estimates of the a Rates for Deformed Superheavy Nuclei 197
/. Silisteanu, W. Scheid, M. Rizea andA.O. Silisteanu
List of Participants
201
FISSION APPROACH TO HEAVY PARTICLE
RADIOACTIVITIES
D.
N. POENARU AND R. A. GHERGHESCU
Horia Hulubei National Institute of Physics and Nuclear Engineering,
RO-077125, Bucharest-Magurele, Romania, E-mail:
W. GREINER
Frankfurt Institute for Advanced Studies, J. W. Goethe Universitat,
Pf 111932, D-60054 Frankfurt am Main, Germany
Heavy particle radioactivity predicted in 1980 was experimentally confirmed since
1984.
The obtained until now data on half-lives and branching ratios relative to
a-decay of
14
C,
18
'
20
O,
23

F, 22,24-26
Nei
28,30
Mg and
32,34g;
rad
i
0
activities are
in good agreement with predicted values within the analytical superasymmetric
fission (ASAF) model. The strong shell effect may be further exploited to search
for new cluster emitters.
1.
Introduction
In order to predict heavy particle radioactivities in 1980 and to arrive at
a unified approach of cluster decay modes, alpha disintegration, and cold
fission, before the first experimental confirmation
3
in 1984, we developed
and used a series of fission theories in a wide range of mass asymmetry,
namely: fragmentation theory, numerical (NuSAF) and analytical (ASAF)
superasymmetric fission models, and a semiempirical formula for a-decay
(see the multiauthored book
*
and the references therein).
As normally expected, being intermediate phenomena between fission
and a-decay, cluster radioactivities have been treated
2
'
1

either as extremely
asymmetric cold fission phenomena or in a similar way to a-decay, but with
heavier emitted particles
4
'
5
. The main difference from model to model con-
sists in the method used to calculate the preformation probability or the
half-life. There are also different relationships for the nuclear radii, inter-
action potentials, as well as for the frequency of assaults on the potential
barrier.
Particularly useful has been the ASAF model, improved successively
1
2
since 1980, allowing us
to
predict the half-lives and branching ratios rela-
tive
to
a-decay for more than 150 different kinds of cluster radioactivities,
including all cases experimentally determined so far. Several other models
have been introduced since 1985 (see the cited papers
in
Refs.
1
and 6).
The performed measurements
7_14
of
cluster decay modes, showing

a
good agreement with calculated half-lives within analytical superasymmet-
ric fission model, are included
in a
comprehensive half-life systematics
15
from which other possible candidates
for
future experiments may
be
ob-
tained. The experimental data on half-lives and branching ratios relative
to a-decay
of
14
C,
18
'
20
O,
23
F, 22,24-26^ 28,30
Mg
and
32,
3
4
Si radioac
.
tivities are

in
good agreement with predicted values within the analytical
superasymmetric fission (ASAF) model.
The fine structure
16
was predicted
17
before the discovery
of
1989
in
Orsay. The measurements
18
with superconducting magnetic spectrometer
SOLENO were repetead with the best accuracy ever obtained
19
in
1995.
2.
Cold fission
In the usual mechanism of fission,
a
significant part (about 25-35 MeV)
of
the released energy
Q is
used
to
deform and excite the fragments (which
subsequently cool down by neutron and 7-ray emissions); hence the total

kinetic energy
of
the fragments, TKE,
is
always smaller than
Q.
Since
1980
a
new mechanism has been experimentally observed
-
cold fission
10
characterized by
a
very high TKE, practically exhausting the Q-value, and
a compact scission configuration. Experimental data have been collected
in two regions
of
nuclei: (a) thermal neutron induced fission
on
some tar-
gets like 233,235
Uj
238
Np)
239,241
p
U)
245

Cni)
^
the
spontaneous fission
of
252
Cf;
(b)
the
bimodal
21
spontaneous mass-symmetrical fission
of
258
Fm,
259,260
Md;
258,262
NO; &nd
260
104 The
yieM
rf the
cold fisgion
mec
hanism
is comparable to that of the usual fission events
in
the latter region, but
it

is much lower (about five-six orders
of
magnitude)
in
the former.
We have systematically studied the cold fission process viewed as cluster
radioactivity within our ASAF model.
22
'
23
The cold fission properties
of
transuranium nuclei
are
dominated
by the
interplay between
the
magic
number of neutrons,
N =
82, and protons,
Z =
50, in one or both fragments.
The best conditions for symmetric cold fission are fulfilled by
264
Fm, leading
to identical doubly magic fragments
132
Sn.

A
spectrum
of
the
234
U
half-
lives versus the mass and atomic numbers
of
the fragments illustrates the
idea
of a
unified treatment
of
different decay modes over
a
wide range
of
3
mass asymmetry. Three distinct groups, a-decay, cluster radioactivities,
and cold fission, can be seen, in good agreement with experimental results.
3.
Region of cluster emitters
From the energetical point of view (released energy Q
>
0) the area of heavy
particle radioactivity
is
extended well beyond that
of

a-decay. Neverthe-
less,
the largest branching ratio with respect
to a
emission experimentally
determined up
to
now is
b
a
= T
a
/T ~
10~
9
. At the limit
of
experimental
sensitivity, the smallest branching ratio measured already
is of
the order
of 10~
16
for
34
Si decay
of
242
Cm and the longest upper limit
of

the
half-
life (for
24
-
26
Ne radioactivity
of
232
Th)
is T >
10
292
s.
Consequently we
126
„
82
• Be
0
C
B
0
sNe oMg
H
Si
Figure 1. Part of the nuclear chart showing the predicted (within ASAF model) emitters
and
the
most probable emitted heavy particles from nuclei heavier than

the
doubly
magic
208
Pb, the region where successful experiments have been performed. The line
of beta-stability
is
marked with black squares. The selection condition was
T <
10
30
s,
b
a
>
1(T
17
.
selected from the very large number
of
cluster emitters those fulfilling si-
multaneously the conditions
T
< 10
30
s
and
b
a
>

10
-17
.
The nuclear chart
of cluster emitters obtained
in
such
a
way
for N >
126 and
Z >
82
is
plotted
in
Fig.
1.
This
is
the region
in
which successful experiments have
been performed.
The cluster emitters
221
Fr,
221
-
224

-
226
Ra,
225
Ac, 228,
23
o
Th)
23ip
aj
230,232-236
U;
236,238p
Ui
and
242
Cm
^
e
j
ther
p^gfofe
or not
f
ar
fr
om
stabil
.
ity nuclei. Few examples from the total of about 300 stable nuclides found

in nature are shown
in
Fig.
1.
Following Green, the line
of
beta stability
can be approximated by
A={Z- 100)/0.6
+ y/(Z -
100)
2
/0.36
+
200Z/0.3
(1)
Another island
of
very proton-rich cluster emitters above the doubly
magic
100
Sn is not shown on the above mentioned figure.
4
4.
Shell effects
The surface of calculated half-lives (within ASAF model) of heavy nuclei
against
14
C radioactivity and the measured points are plotted in Fig. 2.
A strong shell effect can be seen: as a rule the shortest value of the

half-
life (maximum of 1/T) is obtained when the daughter nucleus has a magic
number of neutrons (Nj = 126) and/or protons
{Z&
= 82). For
14
C decay
Figure 2. The surface of calculated half-lives (within ASAF model) of heavy nuclei
against
14
C radioactivity and the measured points. Daughter nuclei are Pb isotopes.
The peak of maximum probability (shortest half-life) corresponds to
222
Ra for which
the daughter is the doubly magic
208
Pb.
modes the peak of maximum probability (shortest half-life) corresponds to
222
Ra for which the daughter is the doubly magic
208
Pb.
As can be seen in table 1, from 26 identified emitters and 9 determined
upper limits (u) one has:
• 9 +2u — doubly magic daughter g^
8
Pb
12
6
• 9 — magic proton number Za = 82

• 6 + 4u — magic neutron number N^ = 126.
225
There are only 2+3u exceptions: Z
d
^ 82 N
d
^ 126:
in -•
10
JNei4 +
80
Ugl28,
'Ac -• i
4
C
8
+ I^Biiag;
233
U -*
2
|Mg
16
+
2
°
5
Hg
125
;
23

*U -+
2
«Mg
16
and
236
U -+
28
.Mg
16
+
2
°
8
Hg
128
.
+ 80
M
g
,127)
5
We continue to present the shell effects in the next section.
Table 1. Performed experiments. Prom 26 identifications and 9 upper limits 24 + 6 belong
to this table. Magic nucleon numbers of the daughter. Par is an abreviation for parent.
Zd =
Par.
222
Ra
226

Th
228
Th
231
Pa
230 TJ
232-[j
233 "[J
234
U
236p
u
238p
u
242
Cm
=
82 N
d
= 126
Fragments
14
C
8
l
8
o
20
O
8

U
23
F
22
Ne
24
Ne
25
Ne
26
Ne
28
Mg
30
Mg
34
Si
20
i
8
Pbl26
i
8
Pb!26
15
8
Pbl26
i
8
Pbl26

I^PblSe
i
8
Pbl26
|§
8
Pb!26
I^PblSe
i
8
Pbl26
§§
8
Pbl26
i
8
Pbl26
Par.
221
Ra
223
Ra
224
Ra
226
Ra
233 TJ
234
n
236

TJ
235
TJ
238p
u
Z
d
= 82
Fragments
14
C
8
14
C
8
14
c
8
14
c
8
24
Ne
24
Ne
24
Ne
25
Ne
28

Mg
i
7
Pb
i
9
Pb
|
2
°Pb
|
2
2
Pb
§°9Pb
§2°Pb
|
2
X
Pb
l
2
°Pb
i
2
°Pb
Par.
221^.
230'pj
1

231
Pa
232
Th
234
TJ
236
TJ
237
Np
238p
u
240p
u
241
Am
N
d
= 126
Fragments
14
C
8
24
Ne
24
Ne
26
Ne
28

Mg
30
Mg
30
Mg
32
Si
34
Si
20
34
Si
20
207
T1
12
6
206
Hgl26
207
Tli26
206
Hg
126
206
Hgl26
206
H
gl2
6

207
T1
126
206
Hgi26
206
Hgl26
207
T1
126
5. New candidates
By comparing the systematics of calculated values and of experimental
data one can list
15
other possible candidates for future experiments:
220,222,223
Fr;
223,224
Ac> and
225
Th
M
u
c
emitte
rs;
229
Th for
20
O radioac-

tivity;
229
Pa for
22
Ne decay mode;
230
'
232
Pa,
231
U, and
233
Np for
24
Ne
radioactivity;
234
Pu for
26
Mg decay mode;
234
-
235
Np and
2
35,237p
u
^
28
Mg

emitters, as well as
238
>
239
Am and
239_241
Cm for
32
Si radioactivity. Also
33
Si decay of
241
Cm could be observed.
In the table 2 one may see
• 3 cases with doubly magic daughter g2
8
Pbi26
• 6 with magic proton number Zd = 82
• 8 with magic neutron number Nd = 126.
There are nine exceptions with Zd ^ 82 Nd ^ 126:
220m. _v 14/"
1
i 206npi . 222r\. _v 14/~< _i_ 208x1
*r ->•
6
^8 + 81
11
125,
*T -t
6

<^8 + 81
il
127)
223
Fr -+ i
4
C
8
+ i?
9
Tl
128
;
224
Ac -»• £
4
C
8
+ H°Bi
127
;
225
Th -»• i
4
C
8
+ l^PoiaT;
230
Pa ->
24

Ne
14
+
I?
6
T1
125
;
232
Pa -+
24
Ne
14
+
1?
8
T1
127
;
234
Np ->
2
lMg
16
+
I°
6
T1
125
,

6
Table 2. Candidates for new experiments; 14 cases with magic nucleon numbers of the
daughter out of the total number 23.
Z
d
= 82 N
d
= 126
Par.
234p
u
240
Cm
241
Cm
Fragments
26
M
g 208p
bl26
32
Si §0
8
Pb
12
6
33
Si i
8
Pbl26

Z
d
= 82
Par.
229
Th
231U
235p
u
237p
u
239
C
m
241 Cm
Fragments
20
O 209
Pb
24
Ne §§
7
Pb
28
Mg
|07
pb
28
Mg §°
9

Pb
32 Si |07p
b
32
Si |09p
b
N
d
= 126
Par.
223
Ac
229p
a
233
Np
235
Np
239
Am
Fragments
14
C
8
209
B
;
126
22
Ne

207
Th26
24
Ne
209
Bii2
6
28
Mg
207
Tll26
32 Si 207
Tll26
and
238
Am -• ?
2
Mg
18
+
2
°
6
T1
125
.
6. Emission of
14
C in competition with
12

C
In 1984 there was a discussion: why
14
C and not the three alphas
12
C is
emitted from
223
Ra? Based on alpha-like theory one would expect a three-a
structure to be preformed and emitted with maximum probability. On the
other hand let us have a closer look at the following equation expressing the
halflife in terms of three model-dependent quantities (frequency of assaults,
preformation probability, and the penetrability of the external part of the
barrier):
T=l
~T
=
~^P
l
°S
T
=
io
sF-^gS-\ogP (2)
where F = In 2/v with v denoting the frequency of assaults on the barrier
in the process of quantum penetrability. As may be seen in Fig. 3, despite
a slightly smaller preformation probability, the Q-value is higher and the
potential barrier for emission of
14
C is smaller so that a higher penetrability

makes a shorter half-life. The shell effects of the emitted particle
6
4
Cg
with
magic neutron number are also playing a role.
7. Half life estimation with the universal curve
The preformation probability can be calculated within a fission model as a
penetrabilty of the internal part of the barrier, which corresponds to still
overlapping fragments. With good approximation, by assuming v = con-
stant and S —
S(A
e
),
one can obtain the universal curve for any kind of
cluster decay mode, including a decay:
logT = - logP - 22.169 + 0.598(A
e
- 1) (3)
7
12 13 14 15 16
45
40
35
30
25
2U
15
It)
45

40
3b
30
25
20
15
10
I
• I ' I '
'
223
R
a
Q(MeV)
log
T(s)
-logs j
log P
7 — -logF(s) S' ~
-
"••••^
^^ ^f
- •^^^ ^^ —
_
^^""N^^
_
— — —
""" "~
• —
1 | 1 | 1 | 1

:
222
Ra :
^~
/
s
' v^
y ^ "
—<\
TV-
^ /
s
^^^Sw S
= , i , \-~T~ i
12 13
14
15 16
Figure 3. Q-values, halflives T, and the three model dependent quantities (F = the
preexponential factor, 5 = preformation probability, and P = the penetrability of ex-
ternal part of the barrier) versus the mass number A
e
of the emitted carbon (Z
e
=6)
cluster from
223
Ra (top) and
222
Ra (bottom).
where the penetrability of the external part of the barrier is easily calculated

- logP = Q.22&7Z{n
A
Z
d
Z
e
R
b
fl
2
[arccos y/r - y/r(l - r)
(4)
with r = Rt/Rb, Rt = 1.2249(A
d
/3
+
Al
/3
),
R
b
= 1.43998Z
d
Z
e
/Q, and
HA
=
A
d

A
e
/A.
Acknowledgments
This work was partly supported by the Centre of Excellence IDRANAP un-
der contract ICA1-CT-2000-70023 with European Commission, Brussels, by
8
UNESCO (UVE-ROSTE Contract 875.737.2),
by
Gesellschaft
fur
Schweri-
onenforschung (GSI), Darmstadt,
by
Bundesministerium
fur
Bildung
und
Forschung (BMBF), Bonn,
and by
Ministry
of
Education
and
Research,
Bucharest.
References
1.
D.N.
Poenaru,

W.
Greiner,
in
Nuclear Decay Modes,
(IOP
Publishing, Bris-
tol,
1996), Chap.
6, pp.
275-336.
2.
A.
Sandulescu,
D. N.
Poenaru
and W.
Greiner,
Sov. J.
Part. Nucl.
11, 528
(1980).
3.
H. J.
Rose
and G. A.
Jones, Nature
307, 245
(1984).
4.
R.

Blendowske,
T.
Pliessbach
and H.
Walliser, Chap.
7 in Ref.
1
, pp.
337-349.
5.
R. G.
Lovas,
R. J.
Liotta,
A.
Insolia,
K.
Varga
and D. S.
Delion, Phys.
Rep.
294,
265
(1998).
6.
D. N.
Poenaru
and W.
Greiner (Eds), Handbook
of

Nuclear Properties
(Clarendon Press, Oxford, 1996).
7.
P. B.
Price, Annu.
Rev.
Nucl. Part.
Sci. 39, 19
(1989);
P. B.
Price
and S.
W. Barwick,
Ch. 8 in Ref.
23
, Vol. II, p. 205.
8.
W.
Henning
and W.
Kutschera,
Ch. 7 in Ref.
23
, Vol. II, p. 188.
9.
E.
Hourany,
Ch. 8 in Ref.
1
, p. 350.

10.
R.
Bonetti
and A.
Guglielmetti,
Ch. 9 in Ref.
1
, p. 370.
11.
Pan
Qiangyan
et al.,
High Energy Phys. Nucl.
23, 1039
(1999); Chinese Phys.
Lett.
16, 251
(1999); Phys.
Rev. C 62,
044612 (2001).
12.
R.
Bonetti,
C.
Carbonini,
A.
Guglielmetti,
M.
Hussonnois,
D.

Trubert
and
C.
Le
Naour, Nucl. Phys.
A 686, 64
(2001).
13.
S. P.
Tretyakova
et al.
Radiat. Meas.
34, 241
(2001);
A. A.
Ogloblin
et al.,
Phys.
Rev. 61,
034301 (2000).
14.
A.
Enulescu
et al.
Radiat. Meas.
28, 555
(1997).
15.
D.N.
Poenaru,

Y.
Nagame,
R.A.
Gherghescu,
W.
Greiner, Phys.
Rev., C65
(2002) 054308; Erratum
C66
049902.
16.
M.
Mirea
and R. K.
Gupta,
in
Heavy Elements
and
Related
New
Phenomena
Vol.
II
(World Scientific, Singapore,
1999) p. 673.
17.
M.
Greiner
and W.
Scheid,

J.
Phys.
G, 12,
L229 (1986).
18.
D. N.
Poenaru
and W.
Greiner (Eds), Experimental Techniques
in
Nuclear
Physics (Walter
de
Gruyter, Berlin, 1997).
19.
E.
Hourany
et al.
Phys.
Rev. C 52, 267
(1995);
E.
Hourany,
I. H.
Plonski
and
D. N.
Poenaru,
Ch. 4 in Ref.
18

, p. 117.
20.
C.
Signarbieux
et al., J.
Phys. Lett. (Paris)
42,
L437 (1981).
21.
E.K.
Hulet
et al.,
Phys.
Rev.
Lett.
56, 313
(1986).
22.
D. N.
Poenaru,
J. A.
Maruhn,
W.
Greiner,
M.
Iva§cu,
D.
Mazilu
and R.
Gherghescu,

Z.
Phys.
A 328, 309
(1987).
23.
D. N.
Poenaru,
M.
Iva§cu
and W.
Greiner,
Ch. 7 in
Particle Emission from
Nuclei,
Vol. Ill (CRC,
Boca Raton,
FL, 1989) p. 203.
MYRRHA, A MULTIPURPOSE EUROPEAN ADS FOR R&D
HAMID AIT ABDERRAfflM*
SCK-CEN,
Boeretang
200,
B-2400
Mol,
Belgium
1.
Introduction
Since 1997 SCK»CEN is developing MYRRHA in collaboration with various
European laboratories as a multipurpose Accelerator Driven System (ADS) for
R&D applications [1]. In its present status, the MYRRHA project is based on

the coupling of a (350 MeV- 5 mA) LINAC proton accelerator with a liquid
Pb-Bi windowless spallation target and a neutron multiplying sub-critical core
(SC) cooled by Pb-Bi in a pool type configuration (see Fig. 1).
2.
Spallation target
The spallation target circuit (see Fig. 2) is fully separated from the core coolant
as a vacuum tight unit whose internal heat production is removed to the SC
pool. For achieving high performance core characteristics, we had to cope with
a drastic geometrical constraint during the spallation target design. Indeed, the
available central hole in the core four housing the spallation source is limited to
roughly 10 cm diameter and that lead to a current density of -130 uA/cm
2
on
the hypothetical window target. Therefore, we decided to design the MYRRHA
spallation target as a windowless target. The choice of using a 350 MeV
protons is also putting a constraint in terms of heat deposition in the target.
Indeed, the proton penetration in the Pb-Bi is limited to 13 cm leading to a heat
deposition of -1.4 MW in a volume of 0.5 liter. This led us to choose the
solution of a liquid Pb-Bi target.
3.
Sub-critical core
The SC has fast neutron spectrum properties and the capability of housing
several islands with thermal spectrum regions located in In-Pile Sections (IPS)
in or at the periphery of the fast core. The fast core is fuelled with typical fast
reactor fuel pins arranged in hexagonal assemblies with an active length of 600
,
9
10
mm. The three central hexagons are housing the spallation module. The
MOX

Proton Beam
Tube
•-I.'
m\
*
r
\
J!
-if
•1 •
Spallation Loop
:for-Pb-Bi
Double-Vessel for
Lead-Bismuth
Eutectic Coolant
I-
i
3
t
t
>
*
•Tl:
I
f w- ^ r -1 •• •
'A
Subcritical Core
•Ylth Spallation
I'arget
Figure 1. MYRRHA spallation loop cut-away.

fuel has Pu contents of 30% and 20%. The Pu isotopic vector is the one typical
resulting from the U0
2
LWR reprocessing.
4.
Containment building
The facility is designed to be operated to a large extent thanks to remote
handling. Therefore, the design called for a dedicated building containment
arrangement as illustrated in Fig. 3.
A remote handling system based on the Man-In-The-Loop principle
implemented with two bi-lateral force reflecting servo-manipulators working
under Master-Slave mode has been recommended on basis of similar
implementation in fusion projects. The slave servo-manipulators will be
11
commanded by remote operators using kinematically identical master
manipulators supported with CCTV feedback. The manipulators will
have
ELECTRICAL MOTOR
• HYDRAULIC
PRIMARY DRIVE
LM CONDITIO!!!)
VESSEL
SUCTION POINT
OF MHDPUMP
IMPELLER SECTION
LM-LM HEAT
EXCHANGER
VACUUM PUMPING
DUCT
GUIDERAILFDR

MOUNTING INTO CORE
CO-AXIAL LM FEED
DRAG LIMITED FLOW
ANNULAR SECTION
SPALLATION
SOURCE FEED
Figure 2. MYRRH A spallation loop cut-away.
additional robotic capabilities to maximize operational capabilities. The slave
manipulators will be positioned close to the task environment by means of
remotely controlled transporters with sufficient reach and degrees of freedom to
position the slave at all relevant locations around the MYRRHA machine. The
concept relies on the ability of the servo-manipulators and the video feedback
systems to create a sense of presence for the operators at the task location. In
practice all of the MYRRHA maintenance tasks will be performed directly by
personnel using the arms, a range of cameras and cranes in much the same way