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Fission Study using Multi-nucleon Transfer Reactions
( Surrogate Reactions )
重イオン多核子移行反応による核分裂特性の研究(代理反応)
Katsuhisa Nishio
Advanced Science Research Center
Japan Atomic Energy Agency
西尾 勝久
日本原子力研究開発機構
先端基礎研究センター
ND2018, 29-30 Nov., Tokyo Institute of Technology1
Japan Atomic Energy Agency (JAEA)
K. Nishio, K. Hirose, H. Makii, R. Orlandi, K. Tsukada, M. Asai, A. Toyoshima, T.K.Sato, Y. Ito, Y. Nagame
University of York, JAEA
A.N. Andreyev
China Institute of Atomic Energy
S. Yan, C.J. Lin
Kindai University
Y. Aritomo, S. Tanaka, Y. Miyamoto, M. Okubayashi, S. Ishizaki
Tokyo Institute of Technology
K. Ratha, S. Chiba
University of Bordeaux
I. Tsekhanovich, B. Jurado
Kyoto University
T. Ohtsuki
ORNL
K. Rykaczewski, R.A. Boll
Collaborators
Tokai Campus, JAEATokyo
Tandem facility
J-PARC
20UR
Contents
☑ Multi-nucleon transfer (MNT) reactions and fission
☑ Experimental setup
☑ Experimental results and discussions
☑ Fission experiments using 254Es
☑ Summary
4
Nuclear Structure and Fission
5
Liquid drop model
Saddle Point
Ground state shape
scission
240U
Including shell energy correction
2nd Saddle point
Ground state shape
scission
Fission isomer
1st Saddle point
Fission fragment mass distributions is one of the important observable
to know the structure of deformed nucleus.
Highly excitation energy Low excitation energy
A.N. Andreyev, K. Nishio, K.-H. Schmidt, Reports on Progress in Physics, 81, 016301(2018)
Measured Fragment Mass/Charge Yield ~1995
Data for low-energy fissions,
Excitation energy ≦ Bf+10MeV
Measured Fission-Fragment Mass/Charge Yields ~2017
R. Léguillon et al., Phys. Lett. B 761, 125 (2016)
K. Hirose et al. Phys. Rev. Letters, 119, 222501 (2017)A.N. Andreyev, K. Nishio, K.-H. Schmidt, Reports on Progress in Physics, 81, 016301(2018)
②原子核構造(理論)Multi-nucleon transfer reactions and fission
In the multi-nucleon transfer (MNT) reactions:
(1) We can generate many nuclei depending on transfer channels.
(2) Excitation energy of compound nucleus distributes widely.
238U
18O
240U*…
16O...
238U
18O
Silicon ΔE-E
Ener
gy
Fission fragment detector
Fission
8Measured and Planned experiments using 18O beam and targets of 232Th, 238U, 248Cm, 237Np, 249Cf, 243Am, 249Bk, 254Es
(1) Fission probability and Fission barrier height.
(2) Fission fragment mass distributions.
(3) Fission fragment angular distributions.
(4) Prompt neutrons accompanied by fission.
Barrier
n
nLiquid Scintillator
(47 detetors )
Experimental Setup
recoilSilicon ΔE-E
DE
DE (75 μm)
12 detectors
E (300 μm)
16 strips
φ
θ
Multi-wire proportional Counter
Targets and Detectors
~ 30 - 60 μg/cm2
~ ø2.0 mm Position Sensitive
200 x 200 mm2
MWPCTarget (248Cm) Silicon ΔE-E detector
ΔE = 75 μm
Thickness fluctuation < 1 μm.
18O + 248Cm (Ebeam= 162MeV)
18O ( 248Cm*) 17O ( 249Cm*) 16O ( 250Cm*)
14C ( 252Cf*) 13C ( 253Cf*) 12C ( 254Cf*)
15N ( 251Bk*) 14N ( 252Bk*)
DE
(MeV
)
Eres (MeV)
Particle Identification using ΔE–E Telescope
O
F
N
C
B
Be
Liα
Elastic Scattering
Fission Probability and Fission Barrier Height
238U(18O, 16O)240U*E
ven
ts /
0.5
MeV
Even
ts /
0.5
MeV
Fis
sio
n P
rob
ab
ility
Excitation Energy (MeV)
238U(18O,16O)240U*
0 5 10 15 20 25
4000
8000
12000
0 5 10 15 20 25
300
600
900
0 5 10 15 20 25
0.1
0.2
0.3
2nd 3rdBf
Bfexp = 5.5 MeV
Excitation energy (MeV)
Fis
sio
n P
robabili
ty
of C
om
pound N
ucle
us
Bfcal = 6.38 MeV (P. Mӧller)
n
n
3rd
2nd
1st
Pote
ntial
Deformation
Fission after neutron evaporation is called “Multi-chance fissions”
238U(18O,17N)239Np*238U(18O,16N)240Np*
238U(18O,16C)240Pu* 238U(18O,15C)241Pu*
Bf(cal) =5.57 MeV 6.01 MeV
5.98 MeV
6.35 MeV
P. Mӧller et al.,
PRC 79, 064304 (2009)
Fission Barrier Height from MNT reactions
Excitation energy (MeV) Excitation energy (MeV)
Excitation energy (MeV) Excitation energy (MeV)
Fiss
ion
Pro
bab
ility
Fiss
ion
Pro
bab
ility
Fiss
ion
Pro
bab
ility
Fiss
ion
Pro
bab
ility5.92 MeV
B.N. Lu et al.,
PRC 89, 014323 (2014)
Poster Presentation by Kean Kun Ratha (PA13)
Extending the Fission Barrier Data using MNT Reactions
Theory (KUYT)Theory (ETFSI)
Theory (Mӧller)
Available Data (33)RIPL-2, RMP (Bjornholm)
JAEA MNT Setup
4
8
12
16
20
U (Z=92)
Pu (Z=94)
Cm (Z=96)
Cf (Z=98)
Fm (Z=100)
Np (Z=93)
Am (Z=95)
Bk (Z=97)
Es (Z=99)
Md (Z=101)
130 140 150 160 170 180 1900
4
8
12
16
20
2468
1012
2468
1012
0.2 MeV
2468
1012
4
8
12
16
20
2468
1012
130 140 150 160 170 180 190
2468
1012
2468
1012
2468
1012
◇Planned at JAEA
We plan to obtain 34 new
fission barrier data using the
reaction of
18O +
237Np, 244Pu, 241,243Am, 248Cm, 249Bk, 249Cf, 254Es
〇
●
18
4
16
2
15
2
18
4
16
2
15
2
Neutron Number
Fis
sio
n B
arr
ier
Heig
ht
(MeV
)
4
8
12
16
20
U (Z=92)
Pu (Z=94)
Cm (Z=96)
Cf (Z=98)
Fm (Z=100)
Np (Z=93)
Am (Z=95)
Bk (Z=97)
Es (Z=99)
Md (Z=101)
130 140 150 160 170 180 1900
4
8
12
16
20
2468
1012
2468
1012
0.2 MeV
2468
1012
4
8
12
16
20
2468
1012
130 140 150 160 170 180 190
2468
1012
2468
1012
2468
1012
Fission Events registered on the Excitation Energy of Compound Nucleus
and Fragment Mass
Fragment Mass (u)
Exc
itat
ion
Ene
rgy
(MeV
)
60 80 100 120 140 160 1800
10
20
30
40
50
60
237Np(18O,19O)236Np*
Bf = 6.3 MeV
Fragment Mass (u)
Excita
tio
n E
ne
rgy (
Me
V)
Fission fragment
mass distributions
34.2 MeV
22.3 MeV
17.8 MeV
16.3 MeV
14.3 MeV
12.8 MeV
E*=12.3-13.3
E*=13.8-14.8
E*=15.8-16.8
E*=17.3-18.3
Fragment Mass (u)
Yie
ld (
%)
E*=21.75-23.75
E*=33.70-35.70
60 80 100 120 140 160 180012345012345012345
237Np(18O,19O)236Np p+235U (Ferguson) p+235U (Ferguson, Broadened with =4.0u)
012345012345
p+235U (Mulgin) p+235U (Broadened with =4.0u)
012345
Fragment Mass (u)Y
ield
(%
)
33.7-35.7 MeV
21.8-23.8 MeV
17.3-18.3 MeV
15.8-16.8 MeV
13.8-14.8 MeV
12.3-13.3 MeV
p + 235U = 236Np*
Ferguson (1973)
Mulgin (2009)
Benchmark of Fission Fragment Mass Distribution (FFMDs)
Excitation Energy
237Np (18O,19O) 236Np*
Present Data
Good agreement with the literature data is found.
Fission Fragment Mass Distributions (FFMDs) obtained in 18O + 237Np
Fragment Mass (u)
237Np 238Np 239Np 238Pu 239Pu240Pu 241Pu
240Am 241Am 242Am 243Am236Np
0
2
4
6
0
2
4
6
0
2
4
6
0
2
4
6
0
2
4
6
0
2
4
6
100 2000
2
4
6
100 200 100 200 100 200 100 200 100 200 100 200 100 200 100 200 100 200 100 200
7-10 MeV
10-20 MeV
20-30 MeV
30-40 MeV
40-50 MeV
50-60 MeV
60-70 MeV
100 200
Yie
ld (
%)
Fission data for 23 nuclides are obtained in the single experiment.
238-241Pu 240-243Am
243Cm 244Cm 245Cm 244Bk 245Bk246Bk 247
Bk246Cf 247Cf 248Cf 249Cf
242Cm
0
2
4
6
0
2
4
6
0
2
4
6
0
2
4
6
0
2
4
6
0
2
4
6
100 2000
2
4
6
100 200 100 200 100 200 100 200 100 200 100 200 100 200 100 200 100 200 100 200
7-10 MeV
10-20 MeV
20-30 MeV
30-40 MeV
40-50 MeV
50-60 MeV
60-70 MeV
100 200
242-245Cm 244-246Bk 246-249CfExcitation Energy (MeV)
50-60
30-40
20-30
10-20
5-10
40-50
60-70
236-239Np
18O + 232Th
18O + 238U
18O + 248Cm
Average Masses of Heavy(H) and Light (L) Fragments
Excitation Energy
Range
= 10 - 20 MeV
1st
chance
2nd
3rd
4th
Effects of Compound Nucleus Neutron-emission on FFMDs Role of Multi-chance Fission on FFMDs
Langevin Calculation240U (E*= 45 MeV)
Poster Presentation by Shoya Tanaka (PA10)
Experimental Data in Comparison with Langevin Calculation
Excitation Energy (MeV)
40-50
30-40
20-30
10-20
0
5
0
5
0
5
0
5
80 1600
5
80 160 80 160 80 160 80 160 80 160 80 160
Yield
(%
)
Fragment mass (u)
E* (MeV)
55
45
35
25
15
238Pu 239Pu 240Pu 241Pu 242Pu 243Pu 244Pu ( = 0.60) ( = 0.55)( = 0.55)( = 0.50)( = 0.50)( = 0.50)( = 0.45)
0
5
0
5
0
5
0
5
80 1600
5
80 160 80 160 80 160 80 160 80 160 80 160
236Np 237Np 238Np 239Np 240Np 241Np 242Np ( = 0.60) ( = 0.55)( = 0.55)( = 0.50)( = 0.50)( = 0.50)( = 0.45)
Yield
(%
)
Fragment mass (u)
E* (MeV)
55
45
35
25
15
0
5
0
5
0
5
0
5
80 1600
5
80 160 80 160 80 160 80 160 80 160 80 160
( = 0.50)( = 0.50)( = 0.45)( = 0.40) ( = 0.50)
Yield
(%
)
Fragment mass (u)
E* (MeV)
55
45
35
25
15
240U 239U 235U 238U 237U 236U 234U ( = 0.35) ( = 0.40)
With multi-chance fission
Without multi-chance fission
234,235,236,237,238,239,240U 236,237,238,239,240,241,242Np 238,239,240,241,242,243,244Pu
Experimental dataLangevin calculation by S. Tanaka, Kindai Univ.
Y. Aritomo and S. Chiba, Phys. Rev. C 88, 044614 (2013).
Fragment Mass (u)
Yie
ld (
%)
Data from 18O+232Th and 18O + 238U
N=146
Effects of Compound Nucleus Neutron-emission on FFMDs Neutron Multiplicity at the Excitation Energy corresponding to
Thermal Neutron-induced Fissions
● This work□ JENDL-4.0
Mass number of Fissioning Nucleus
ҧ𝜈Np Pu Am
Toward Understanding the Spins of Compound Nucleus
(1) Fission Probability F
issio
n P
rob
ab
ility
Excitation Energy (MeV)
Statistical Model Calculation
We are getting an evidence that
fission probability changes with
scattering angle.
238U
18O
240U*…
16O...
238U
18O
Fission probability changes with the spins of compound nucleus.
Fission fragment angular distribution has Information on spins of compound nucleus.
J (rotation) Axis
Ejectile
K
Fragment
Fragment
𝜃𝑓
Projectile
θ
φ
238U(18O,16O)240U*
W=
d
fiss/dW
(arb
.)cosqf
No Rotation
Toward Understanding the Spins of Compound Nucleus
(2) Fission Fragment Angular Distribution
We are getting an evidence that compound
nucleus spins are proportional to the number of
transferred nucleons.
258Fm
Literature data for Spontaneous fission
AsymmetricSharp
Symmetric
Fissions of Fermium and Heavier-element Isotopes
256Fm
254Es (T1/2=276 days)99
Multi-Mode Fissions
Standard mode
Several fission modes can coexist in heavy- & neutron-rich nuclei.
Mixture of three modes
Two cluster-like
A. Staszczak et al., Phys. Rev. C 80, 014309 (2009). 25
Neutron-rich Nuclei
Super-heavy Elements
254Es from Oak Ridge National Labratory
https://neutrons.ornl.gov/hfir
Fermium (element 100 )
Einsteinium (99)
Californium (98)
Berkelium (97)
Curium (96)
0.3 μg of 254Es obtained in Oct 2017.
We plan to obtain it in 2019.
~ μg
~ ng
~ mg
Seed nuclides
4He
Start detector
254Es
Stop detector
Fragment 1
Fragment 2
Multi-wire proportional Counter
e-
Fragment
e-Film
Micro-channel Plate
Detector
In-beam fission measurement in 4He + 254Es = 258Md*101
27
254Es Target
(10 ng on Φ2mm)
BeamTarget
Fragment 2
Fragment 1
Double-Velocity Measurement
60 80 100 120 140 160 180 20050
100
150
200
250
300
TKEaverage
Q-value
Fragment mass (u)
TK
E (
MeV)
250Cf
Spontaneous Fission
60 80 100 120 140 160 1800
1
2
3
4
5
6
7
250Cf
Yie
ld (%
)
Fragment Mass (u)
Present
Hoffman
Fission of 250Cf and 258Md* (Preliminary Data)
254Es
D.C. Hofmann et al.,
Phys. Rev. C, 7, 276 (1973)
α
250Cf (Spontaneous Fission)
Yie
ld (
%)
To
tal K
ine
tic E
nerg
y (
MeV
)
Fragment mass (u)
Q-value
Hofmann
(1973) Present
β-250Bk
60 80 100 120 140 160 180 2000
1
2
3
4
5
6
7
258Md
Yie
ld (%
)
Fragment Mass (u)
Present
E* = 15.0 (MeV)60 80 100 120 140 160 180 200
50
100
150
200
250
300
350
TKEaverage
Q-value
Fragment mass (u)
TK
E (
MeV)
258Md
E* = 15.0 (MeV)
Fragment mass (u)
Yie
ld (
%)
4He + 254Es = 258Md ( Excitation energy 15.0 MeV )
To
tal K
ine
tic E
nerg
y (
MeV
)
4He
Q-value
Present
98 101
Summary
☑ Multi-nucleon transfer reaction is a powerful tool to study fission and to
take fission data. Fission data include information of MNT process itself.
☑ Effects of multi-chance fission on fission fragment mass distributions
are discussed.
☑ We plan to measure the fission barrier data up to mendelevium (Md),
the element 101.
☑ Assignment of the spins of compound nucleus is our next challenge.
☑ We started to obtain fission data for fermium region using 254Es, for the
strong benchmark of fission model. 29
25 – 27 March 2019, Tokai, Japan