Abdenbi KHOUAJA Reaction cross section and strong absorption radius measurements of neutron-rich...
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Abdenbi KHOUAJA
Reaction cross section and strong absorption radius measurements of neutron-rich exotic nuclei
in the vicinity of closed shells N=20 and N=28
Reaction cross section and strong absorption radius measurements of neutron-rich exotic nuclei
in the vicinity of closed shells N=20 and N=28
I.N.F.NLaboratorio Nazionale del Sud
Catania
He3 He4 He6 He8
Li6 Li7 Li8 Li9 Li11
Be7 Be9 Be10 Be11 Be12 Be14
B8 B10 B11 B12 B13 B14 B15 B17 B19
C9 C10 C11 C12 C13 C14 C15 C16 C17 C18 C19 C20 C22
N12 N13 N14 N15 N16 N17 N18 N19 N20 N21 N22 N23
O13 O14 O15 O16 O17 O18 O19 O20 O21 O22 O23 O24
F17 F18 F19 F20 F21 F22 F23 F24 F25 F26 F27 F29
Ne17 Ne18 Ne19 Ne20 Ne21 Ne22 Ne23 Ne24 Ne25 Ne26 Ne27 Ne28 Ne29 Ne30 Ne32
Na20 Na21 Na22 Na23 Na24 Na25 Na26 Na27 Na28 Na29 Na30 Na31 Na32 Na33 Na34 Na35
Mg21Mg20 Mg22Mg23Mg24Mg25Mg26Mg27Mg28Mg29Mg30Mg31Mg32Mg33Mg34Mg35Mg36
Ca35 Ca36 Ca37 Ca38 Ca39 Ca40 Ca41 Ca42 Ca43 Ca44 Ca45 Ca46 Ca47 Ca48 Ca49 Ca50 Ca51 Ca52
Al22 Al23 Al24 Al25 Al26 Al27 Al28 Al29 Al30 Al31 Al32 Al33 Al34 Al35 Al36 Al37 Al38 Al39
Si22 Si23 Si24 Si25 Si26 Si27 Si28 Si29 Si30 Si31 Si32 Si33 Si34 Si35 Si36 Si37 Si38 Si39 Si40 Si41 Si42
P26 P27 P28 P29 P30 P31 P32 P33 P34 P35 P36 P37 P38 P39 P40 P41 P42 P43 P44 P45 P46
S27 S28 S29 S30 S31 S32 S33 S34 S35 S36 S37 S38 S39 S40 S41 S42 S43 S44 S45 S46 S47
Cl31 Cl32 Cl33 Cl34 Cl35 Cl36 Cl37 Cl38 Cl39 Cl40 Cl41 Cl42 Cl43 Cl44 Cl45 Cl46 Cl47 Cl48 Cl49
Ar31 Ar32 Ar33 Ar34 Ar35 Ar36 Ar37 Ar38 Ar39 Ar40 Ar41 Ar42 Ar43 Ar44 Ar45 Ar46 Ar47 Ar48 Ar49 Ar50 Ar41
S48
K35 K36 K37 K38 K39 K40 K41 K42 K43 K44 K45 K46 K47 K48 K49 K50 K51 K52
Ca53
28
26
24
22
2018
16
1412
10
8642
A.C.C.Villari et al. en 1991
N.Aissaoui et al en 1999
Chulkov, Suzuki, Ozawa et al. en 2001
I.Licot et al en 1997
Reactio
n cross
sectio
n (σ R)
to be m
easured
Ne31
Goal of the experience
Y.H.Zhang et al. en 2002
Available data of the reaction cross-section
Primary beam
Secondary beam
Alpha Spectrom
eter
GA
NIL
Degrader
9Be with thickness of 25µm
48CaEnergy=60.3A MeV
Intensity=4000nAe
Production target181Ta
22C 21C23N
17B14Be11Li
29F
32Ne
35Na
38Mg
41Al
43Si
44P45S
47Cl
New
reac
tion
cros
s sec
tion
mea
sure
men
ts
Experiment Details
L. Bianchi et al., Nucl. Instr. and Meth. A276 (1989) 509.W. Mittig et al., Bormio, Italy 1986A. Gillibert et al., Phys. Lett. B176(1986)317.
M = Q B/L.Tvol
B= M V/Q
Long flight path = 82m Time of flight ~ 700ns - 1.2 sm/m ~ 10-4
SISSISISSI
Spectromètre Spectromètre AlphaAlpha
SPEG
NaI
NaI
beam
dE1dE2
EbarE
Silicon Telescope
SPEG-GANIL
NaI
NaI
Reaction cross-sectionDirect method developed by A.C.C.Villari
(which is a variant of the known transmission method)
In this method, the stack of Silicon detectors is used as both :
Reaction target
Detection system
max
max
0
max
0 1ln/
RNd
PA
dR
dEdEdRE
A
RR
E
R
R
Masse (MeV)~Etot.Tvol2
Typical mass spectra as a function of the total energy (~ET2) for 25F (E= 45.5A MeV). Energy resolution ~ 0.23%. Effective resolution Q=2.58MeV
Spectrum obtained directly from the silicon detectors
Spectrum in coincidence with emitted gammas
Spectra (a) :
Spectra (b) :
i
reaR N
NP
coinccorrcorr
reaNN
i
reaR N
NNP
reaction probability
Reaction probability PR
)1ln(
1(2
3/13/1
3/13/13/13/12
0
R
cm
b
tP
tPtPR
Pcste
E
VEC
AA
AAaAAr
Reduced strong absorption radius :
Parametrization of S.Kox
Results
More than 70 radii are measured
19 radii are measured for the first time:
27F, 27, 30Ne, 33Na, 28, 34-35Mg, 36-38Al, 38-40Si, 41-42P, 42-44S, 45Cl.
PAEEC /014.031.0
Parametrization of the reduced strong absorption radii:
Z≤13 : evolution according to :W.Mittig et al., Phys. Rev. Lett. 59, 1889 (1987)
Z≥13 : evolution according to:N.Aissaoui et al., Phys. Rev. C60, 034614 (1999)
1)(06.020 ZNr
30/3230/)(20 ZNr
8≤Z≤18 and 12≤A≤46 :
22
20
628.4282.0164.1 Tz
ATz
Ar
r02
TZ/A
stab
ilit
y
r02r0
2
New parametrization
A.Khouaja et al (ENAM04)
A.Khouaja et al (EXON04)
Strong influence of the isospin is revealed for each isobar, New parametrization permits : To study the evolution of the matter distribution : efficiently reproduces the skin effect To give a fast indication on the existence of abnormal structures: deformation, halo… for these nuclei: 23N, 29Ne, 33Na, 35Mg, 44S, 45Cl, and 45Ar
35Mg
44S
41Ar
33Na
45Ar45Cl
Glauber Model
The effective nuclear matter radii “RMS”
The effective density distributions
permits us to deduce:
Coulomb-modified Glauber Model:
0
)(1)1(2 bdbbE
V
cm
CR
)()()()( 212122
12 bbbbbfbdbdb P
zCz
)()( 22
,, zbdzb CPCP
z
CP
pnCPnpCPnnCPppCPNNtot AA
NZZNNNZZ
))(exp()( bbT NNtot
Thickness density :
:
Transparency function :
)2
exp(4
1)(
2
2
2NNNN
bbf
089.0)679.106
exp(996.0 E
NN
Profile function :
T. ZHENG et al., Nucl. Phys. A709, 103 (2002)R.M. Devries et al., Phys. Rev. C22, 1055 (1980)
1
22,
22,
2
32,
0, 14
3
pFk
pFk
pFkk R
a
R
k
pFk
pFk
kpFk
a
Rrr
2,
2,
0,2,
exp1)(
)( 3/13/122, NorZrR pFpFk
22,
22,
22
2,2
3
71
5
3
pFn
pFnpFnn R
aRr
22,
22,
22
2,2
3
71
5
3
pFp
pFppFpp R
aRr
npm rANrAZr 222 )/()/(
2/122/12pn rrR
Matter radii: Radius Mean Square
Matter distribution: using 2pF density distribution
Skin effect
where: k=Z or N
Two free parameters
fmNaRNaR pFnA
pFp 114.3)()( 232,2,
fmNaaNaa ApFp
ApFn 401.0)()( 2,2,
.
3/12, ZrR ppFp pa
Absence of data at intermediate energy:
T.Suzuki et al.,
Phys. Rev. Lett. 75, 3244 (1995)
Presence of data at intermediate energy :
We disentangle: 3/12, NrR npFn and,
The results of T.Suzuki (Phys. Rev. Lett. 75, 3244 (1995))
Actual work
na,
Conclusion
In the same setup, more than 70 reaction cross sections are measured The measurements , for the first time, of 19 new reaction cross sections
New phenomenological parametrization is suggested for the nuclear radii in the region of closed shells N=8 and N=28, which permits :
to reproduce the skin effect far from stability to give a current indications on the existence of abnormal structure: 23N, 29Ne, 33Na,
35Mg, 44S, 45Cl, and 45Ar
We disentangle the effect of nuclear size and surface diffusivity of matter distribution using Glauber model.
Great thanks to MAGNEX’s group:A.Cunsolo, F.Cappuzzelo, J.S.Winfield,
C.Nocifiro, A.Khouaja, A.Foti, S.E.A.Orrigo, M.Cavallaro
Collaborators:D.Hirata Open University, U.KA.C.C.Villari GANIL, Caen, FranceM.Benjelloun LPTN, El jadida, MoroccoA.Khouaja LNS-INFN, Catania, Italy
Participants:H.SAVAJOLS1, W.MITTIG1, P.ROUSSEL-CHOMAZ1, N.ORR2, S. PITAE1, C.E.DEMONCHY1, L.GIOT1,
M.CHARTIER3, A.GILLIBERT4, D. BAIBORODIN5, Y. PENIONZHKEVICH6, W.CATFORD7, A.LÉPINE-SZILY8, Z.DLOUHY6
1GANIL (IN2P3/CNRS – DSM/CEA), B.P. 55027 14076 Caen Cedex 5 France2LPC, ISMRA et Université de Caen, F-6704 Caen, France
3University of Liverpool, Dept. of Physics, Liverpool, L69 7ZE, UK4SPHN (DAPNIA/CEA), CEN Saclay, F-91191 Gif-sur Yvette, France
5FLNR, JINR, Dubna, P.O.Box 79, 101000 Moscow, Russia6Nucl.Phys.Ins., ASCR, 25068 Rez, Czech Republic
7University of Surrey, Stoy Fill, Nuclear Physics Dept, Guilford, GU27XH, UK8University of São-Paulo, IFUSP, C.P.66318, 05315-970 São –Paulo, Brazil
)2
exp(4
1)(
2
2
2NNNN
bibf
)2
exp(4
1)(
2
2
2NNNN
bbf
089.0)679.106
exp(996.0 E
NN
42
2
67.68/76.8/04.1573.13
85.113/26.25/18.1867.70
nnpp
np
cv /
NNtot
avec
)()()(exp12)( 212122
12 bbbbbfbdbddbbb P
zCz
NNtotR
)()(exp12)( 1112 bbbbddbbb P
zCz
NNtotR
finite range
zero range
R.M. Devries et al., Phys. Rev. C22, 1055 (1980)
T. ZHENG et al., Nucl. Phys. A709, 103 (2002)
S.K Charagi et al., Phys. Rev. C41, 1610 (1990)
profile function :
Discovery of a new magic number, N=16 :
A.Ozawa et al., Phys. Rev. Lett. 84, 5493(2000)
Possible existence of one-neutron halo structure : 22N, 23O, 24F
Appearance of a new magic number N=16
Magic number
Matter distribution far from stability Halo structure
Skin structure
RMF: 1n-halo nuclei: 33Na, 34Na and 35Mg
T.Suzuki et al, Nucl. Phys. A616, 286c (1997)
J.S.Wang et al., Nucl. Phys. A691, 618(2001)
17B14Be
11Be
11Li
8He
6He
I.Tanihata et al, Phys.Lett. B206, 592 (1988)
Our results are slightly small to the results of T.SuzukiThe precision of different results are amelioratedAs a preliminary results, the skin effect is revealed in the structure of these nuclei
2.79 0.132.63 0.030.262.740. 042.480.043.332.970.24724Ne
2.82 0.042.74 0.030.272.850.042.580.043.222.810.37025Ne
2.86 0.052.82 0.020.262.920.032.660.023.022.590.4726Ne
2.96 0.052.83 0.040.302.950. 052.650.053.583.160.27027Na
3.04 0.032.93 0.020.323.050.032.740.033.483.010.38528Na
3.06 0.062.98 0.020.333.100.032.770.033.402.880.44029Na
3.01 0.102.91 0.050.253.010. 062.770. 063.383.010.40029Mg
3.08 0.082.99 0.020.293.100.032.810.033.473.030.41530Mg
3.12 0.133.04 0.030.363.180. 052.810.043.703.170.37031Mg
Rn, 2pFRp, 2pFa2pFNoyaux 2/12
nr R 2/12mr T.Suzuki2/12
pr