Angular momentum generation in nuclear fission
J. N. N Wilson
(1)
,
D. Thisse
(1)
,
M. Lebois
(1)
,
N. Jovančević
(1)
,
D. Gjestvang
(2)
,
R. Canavan
(3)
,
M. Rudigier
(4)
,
D. Etasse
(5)
,
R-B. Gerst
,
L. Gaudefroy
(6)
,
E. Adamska
(7)
,
P. Adsley
(1)
,
A. Algora
(8)
,
M. Babo
(1)
,
K. Belvedere
(3)
,
J. Benito
(9)
,
G. Benzoni
(10)
,
A. Blazhev
(11)
,
A. Boso
(12)
,
S. Bottoni
(10)
,
M. Bunce
(12)
,
R. Chakma
(1)
,
N. Cieplicka-Oryńczak
(13)
,
S. Courtin
(14)
,
M. L Cortés
(15)
,
P. Davies
(16)
,
C. Delafosse
(1)
,
Muriel Fallot
(17)
,
B. Fornal
(13)
,
L. Fraile
(9)
,
A. Gottardo
(18)
,
V. Guadilla
(17)
,
G. Häfner
(1)
,
K. Hauschild
(1)
,
M. Heine
(14)
,
C. Henrich
(4)
,
I. Homm
(4)
,
F. Ibrahim
(1)
,
Ł. W Iskra
(10)
,
P. Ivanov
(12)
,
S. Jazrawi
(3)
,
A. Korgul
(7)
,
P. Koseoglou
(11)
,
T. Kröll
(4)
,
T. Kurtukian-Nieto
(19)
,
L. Le Meur
(17)
,
S. Leoni
(10)
,
J. Ljungvall
(1)
,
A. Lopez-Martens
(1)
,
R. Lozeva
(1)
,
I. Matea
(1)
,
K. Miernik
(7)
,
J. Nemer
(1)
,
S. Oberstedt
(20)
,
W. Paulsen
(2)
,
M. Piersa
(7)
,
Y. Popovitch
(1)
,
C. Porzio
(10)
,
L. Qi
(1)
,
D. Ralet
(21)
,
P. H Regan
(3)
,
K. Rezynkina
(18)
,
V. Sánchez-Tembleque
(9)
,
S. Siem
(2)
,
C. Schmitt
(14)
,
P.-A. Söderström
(22)
,
C. Sürder
(4)
,
G. Tocabens
(1)
,
V. Vedia
(9)
,
D. Verney
(1)
,
N. Warr
(11)
,
B. Wasilewska
(13)
,
J. Wiederhold
(4)
,
M. Yavahchova
(23)
,
F. Zeiser
(2)
,
S. Ziliani
(10)
1
IJCLab -
Laboratoire de Physique des 2 Infinis Irène Joliot-Curie
2 UiO - University of Oslo
3 Department of Physics, University of Surrey
4 TU Darmstadt - Technische Universität Darmstadt - Technical University of Darmstadt
5 LPCC - Laboratoire de physique corpusculaire de Caen
6 DAM/DIF - DAM Île-de-France
7 UW - University of Warsaw
8 UV - Facultat de Fisica [València]
9 UCM - Universidad Complutense de Madrid = Complutense University of Madrid [Madrid]
10 UNIMI - Università degli Studi di Milano = University of Milan
11 Institut für Kernphysik der Universität zu Köln
12 NPL - National Physical Laboratory [Teddington]
13 IFJ - Instytut Fizyki Jądrowej PAN
14 IPHC - Institut Pluridisciplinaire Hubert Curien
15 RIKEN - RIKEN - Institute of Physical and Chemical Research [Japon]
16 University of Manchester [Manchester]
17 SUBATECH - Laboratoire de physique subatomique et des technologies associées
18 INFN, Sezione di Padova - Istituto Nazionale di Fisica Nucleare, Sezione di Padova
19 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan
20 JRC - European Commission - Joint Research Centre [Geel]
21 GANIL - Grand Accélérateur National d'Ions Lourds
22 Horia Hulubei Natl Inst Phys & Nucl Engn IFIN HH, ELI NP Dept, Reactorului Str 30, Magurele 077125, Romania
23 Софийски университет = Sofia University
2 UiO - University of Oslo
3 Department of Physics, University of Surrey
4 TU Darmstadt - Technische Universität Darmstadt - Technical University of Darmstadt
5 LPCC - Laboratoire de physique corpusculaire de Caen
6 DAM/DIF - DAM Île-de-France
7 UW - University of Warsaw
8 UV - Facultat de Fisica [València]
9 UCM - Universidad Complutense de Madrid = Complutense University of Madrid [Madrid]
10 UNIMI - Università degli Studi di Milano = University of Milan
11 Institut für Kernphysik der Universität zu Köln
12 NPL - National Physical Laboratory [Teddington]
13 IFJ - Instytut Fizyki Jądrowej PAN
14 IPHC - Institut Pluridisciplinaire Hubert Curien
15 RIKEN - RIKEN - Institute of Physical and Chemical Research [Japon]
16 University of Manchester [Manchester]
17 SUBATECH - Laboratoire de physique subatomique et des technologies associées
18 INFN, Sezione di Padova - Istituto Nazionale di Fisica Nucleare, Sezione di Padova
19 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan
20 JRC - European Commission - Joint Research Centre [Geel]
21 GANIL - Grand Accélérateur National d'Ions Lourds
22 Horia Hulubei Natl Inst Phys & Nucl Engn IFIN HH, ELI NP Dept, Reactorului Str 30, Magurele 077125, Romania
23 Софийски университет = Sofia University
R-B. Gerst
- Fonction : Auteur
G. Benzoni
- Fonction : Auteur
- PersonId : 755374
- ORCID : 0000-0002-7938-0338
C. Delafosse
- Fonction : Auteur
- PersonId : 1264426
- IdHAL : c-delafosse
Muriel Fallot
- Fonction : Auteur
- PersonId : 177532
- IdHAL : muriel-fallot
- ORCID : 0000-0001-8650-2578
- IdRef : 070163537
B. Fornal
- Fonction : Auteur
- PersonId : 755162
- ORCID : 0000-0002-1142-8067
- IdRef : 219941858
K. Hauschild
- Fonction : Auteur
- PersonId : 750506
- IdHAL : karl-hauschild-ijclab
- ORCID : 0000-0003-2862-2445
- IdRef : 196405564
S. Leoni
- Fonction : Auteur
- PersonId : 755161
- ORCID : 0000-0002-3691-0749
J. Ljungvall
- Fonction : Auteur
- PersonId : 737836
- IdHAL : joa-ljungvall
- ORCID : 0000-0003-1938-1889
- IdRef : 234661593
A. Lopez-Martens
- Fonction : Auteur
- PersonId : 755144
- IdHAL : araceli-lopez-martens
- ORCID : 0000-0001-9985-6228
- IdRef : 163696829
S. Ziliani
- Fonction : Auteur
- PersonId : 763971
- ORCID : 0000-0001-5328-720X
Résumé
When a heavy atomic nucleus splits (fission), the resulting fragments are observed to emerge spinning1; this phenomenon has been a mystery in nuclear physics for over 40 years2,3. The internal generation of typically six or seven units of angular momentum in each fragment is particularly puzzling for systems that start with zero, or almost zero, spin. There are currently no experimental observations that enable decisive discrimination between the many competing theories for the mechanism that generates the angular momentum4,5,6,7,8,9,10,11,12. Nevertheless, the consensus is that excitation of collective vibrational modes generates the intrinsic spin before the nucleus splits (pre-scission). Here we show that there is no significant correlation between the spins of the fragment partners, which leads us to conclude that angular momentum in fission is actually generated after the nucleus splits (post-scission). We present comprehensive data showing that the average spin is strongly mass-dependent, varying in saw-tooth distributions. We observe no notable dependence of fragment spin on the mass or charge of the partner nucleus, confirming the uncorrelated post-scission nature of the spin mechanism. To explain these observations, we propose that the collective motion of nucleons in the ruptured neck of the fissioning system generates two independent torques, analogous to the snapping of an elastic band. A parameterization based on occupation of angular momentum states according to statistical theory describes the full range of experimental data well. This insight into the role of spin in nuclear fission is not only important for the fundamental understanding and theoretical description of fission, but also has consequences for the γ-ray heating problem in nuclear reactors13,14, for the study of the structure of neutron-rich isotopes15,16, and for the synthesis and stability of super-heavy elements17,18.
Domaines
Physique [physics]| Origine | Fichiers produits par l'(les) auteur(s) |
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