Lou Jian-Ling, Chen Jie，Ye Yan-Lin
Peking University, China
November 8th, 2015
JCNP2015
Content
 Motivation
 Experimental setup
 Data analysis
 Summary and disscussion
The halo nucleus 11Be
 Neutron loosely bound
Sn=0.504 MeV
 Larger radius
rms= 2.91 fm
 Parity inversion： intruder state
 10Be core + 1 valance n
Intruder
dominate
10Be
Core excited to 2+
PRC 85 (2012) 051303R
0 d3/2
1 s1/2
0 d5/2
⑳
11Be
inversion
⑧
0 p1/2
0 p3/2
+)
gs(1/2
0 p1/2
1 s1/2
0
0+ × 1s1/2
s1/2
PRL 108, 192701 (2012),10Be(d,p)
S~0.71(5)
0 d5/2
0
p1/2
2+
2+ × 0d5/2
PLB 461, 22-27 (1999) 11Be(p,d) S~16%
PRL 84, 35(2000) 11Be 1n removal
S~22%
Reaction， momentum distribution
12Be = 11Be + n
Intruder state
[6]F. C. Barker, J. Phys. G 2, L45 (1976).
Normal state
12Be
•Isomeric state： 02+ 331(12) ns
Two decay modes:
E2 decay: 130 keV and 2.11 MeV gamma-rays
E0 decay: internal conversion: negligible
e+e- pair creation 511keV gamma
17(2)%
isomer
83(2)%
Physics Letters B 560 (2003) 31–36;
Physics Letters B 654 (2007) 87-91.
0 d3/2
1 s1/2
0 d5/2
⑳
12Be (0+
gs
)
⑧
0 p1/2
0 p1/2
0 p3/2
0 s1/2
(0s)4(0p)8 0ћω
Normal
1 s1/2
0 d5/2
(0s)4(0p)6(1s0d)2 2ћω
Intruder state
01+ G.S
02+ Isomer
Inutruder
normal
intruder
Isomer
reference
No data: no data or no calculation
Not: Intruder state is not dominant
Dominant: Intruder state is domina
Uncertainty: no d-wave, could not m
norm
al
s
d
p
F.C.Barke
33
34
32
56
2
42 Dominant dominant J.Phys.G 36,038001,2009;
J.Phys.G 2, L45,1976
H.T.Fortune and
R.Sherr
53
15
32
25
7
68 dominant
Not
Phys.Rev.C 74,024301,2006; J.Phys.G
038002,2009;
Phys.Rev.C83,044313,2011.
C.Romero-Redondo
Three –body model
?
10- 13-19 1513
23
68
?
Not
Phys.Rev.C 77,054313,2008.
G.Blanchon pp-RPA
25
18.5
0
19 Not
M.Dufour
58
s d
G.S
74
p
dominant
dominant Phys.Rev.C 82,034313,2010.
NCSM
16
59
no
Not
No data
Nucl.Phys.A 836,242,2010.
Knock -out reaction
68
32
no
dominant
No data
Phys.Rev.Lett 85,266,2000;
Phys.Rev.Lett 96,032502,2006.
no
60 dominant
Not
Phys.Rev.lett 108,122501,2012.
0.56
0.48
0.44
Charge exchange
reaction
no
no
25
Transfer reaction
0.28
no
no
0.73 no
no uncertainty dominant
~0.20
no
no
0.32- no
0.95
no uncertainty uncertainty Phys.Rev.C 88,044619,2013
no
Phys.lett.B 682,391,2010.
Ground state：transfer reaction could not give the unambiguous result, are no conflict with
Isomeric state：transfer reaction contradict with Charge-exchange
Knock-out experiment(2ћω)
 78 MeV/u
12Be+9Be(s
wave)
Phys.Rev.Lett 85,266,2000.
don’t distinguish (1s1/2)2 and (0p1/2)2 configurations ------gamma rays
not sensitive to the (0d5/2)2 configuration--------10Be+n fragments
 39 MeV/u
12Be+12C(s
p d wave)
Phys.Rev.Lett 96,032502,2006.
4 NaI detectors: detect the first excited state of 11Be at 320keV(0p1/2)
Demon: detect n, n+10Be reconstruct the excited state of 11Be at 1.78
MeV(0d5/2)
Discriminate isomeric states from ground state
12B(1+)(7Li, 7Be)12Be(
2ћω) Phys.Rev.Lett 108,122501,2012.
 Gamow-Teller transition
Selected rules: Δ L=0, Δ S=1 , Select p-wave（normal）.
 Clearly distinguish the first two 0+ states of 12Be.
01+ 25（5)% 02+ 60(5)% --intruder states are dominant
for ground state(01+), but not for isomeric state( 02+)
11Be(d,p)12Be
reaction(0ћω) Phys.Lett.B 682,391,2010.
 Two annular DSSD
Phys Rev C 88,044619,2013
 Select s-wave（abnormal）
 Identify the excited states of 12Be
01+ 0.28 ,
02+ 0.73 , intruder state dominate
Phys.Rev.C 85,051303(R),2012.
1. 01+ ：normalization,
unsure deuterium content
2. 02+ : Mix with 2+ state.
separate them incorrectly
Normalization factor for beam.
Incident energy is about 2.8 MeV/nucleon
Target thickness: 1.0 mg/cm2
No 0-degree detectors due to higher beam intensity
Thick target and Gamma detectors to discriminate the excited states of 12Be.
01+， SF = 0.15~0.25；
02+ ， SF = 0.32-0.98.
(1) For 01+:
no coincidence with 12Be
Larger background
(2)For 02+
Larger C.M angles
(3) No elastic scattering data
For 11Be+d and 12Be+p
G.S SF = 0.15 ~ 0.25
Isomeric： SF = 0.32 ~ 0.95 .
OPs of entrance channel (11Be+d) and exit channel (12Be+p) affect SF extraction largly.
Goal of the proposed experiment
 Main goal:
Investigate the intruder s-wave strength in the ground state and
low-lying excited state of 12Be via the d(11Be,p) transfer reaction
at 20-30 MeV/u.
 20-30 MeV/u : to get the highest beam intensity
1. SF is independent of the incident energy in large energy range
2. reduce the effect of complicated reaction mechanism
3. beam production rate times reaction cross sections
4. 55MeV/nucleon 12Be+p elastic scattering data exist
The New ideas
 Decrease the background
Coincident measurement of 10-12Be and light-charged particles
 Measure the elastic scattering Channel at the same experiment
 remove the effect of proton in CD2 target
Compare the elastic scattering data of 11Be+p to 11Be+d to get the
proton content in CD2 target.
 New technique to separate 02+, measure Smaller angles data
implantation-decay-detect gamma( stopping and decay)
Kinematics
Experimental Setup
C, CD2, CH2, Empty target were used.
 Beam :






Primary beam: 13C
Energy:
57.7 MeV/u
Intensity at F3: 1.5*10^4pps
Purity:
95%
Contamination: mainly 9Li
Energy dispersion: 2%
Intensity:
800 enA
Secondary beam : 11Be
On zero Tele: 2.0*10^4pps
Energy: 27 MeV/nucleon
Beam time:
10 days
Beam
11Be,
about 95%
9Li
8Li
Elastic scattering Data of 11Be+p
and 11Be + d
Extract Optical potential for the
Entrance channel of transfer reaction
11Be
elastic and inelastic scattering on proton
PID in Tele0
Cut 11Be
Elastic scattering
Cut 10Be
Break up
ADWA method：
Provide the OP
Of entrance channel
Systematic is good.
Require normalization
Factor
Provide by D.Y.Pang and J.Chen
[1] 38.3 MeV/nucleon PLB 2008, 658: 198-202
[2] 49.3 MeV/nucleon PLB 1997, 401: 9-14
[3] 63.7 Mev/nucleon PLB 2004,596: 54-60
Provide by A.M.Moro
DCE: dynamic core excitation
CDCC: Continuum discreted
coupled channel
XCDCC: Extended CDCC,
include core excitation
with core
excitation
Without core
excitation
11Be
elastic and inelastic scattering on deuteron
Energy in DSSD / artificial unit
PID on the zero degree telescope
energy spectrum for 11Be
cut 11Be on Tele0
11Be
cut 10Be on Tele0
10Be
Energy in SSD/MeV
Energy/MeV
Provide by D.Y.Pang and J.Chen
Global JLM potential can reproduce
the Angular distribution of 11Be+d
DWBA: provide 11Be+d OP
[1] PRC 83, 064619 (2011)
[2] JPG 39 (2012) 095101
Provide by A.M.Moro
Good d + 10Be OP, Need more discussion
Angle of deuteron(degree)
Energy of deuteron(MeV)
Angle of 11Be(degree)
nergy of deuteron(MeV)
Counts
H in CD2 target (9.5%)
Angle of Deuteron(degree)
OP of the exit channel
We need 51 MeV/nucleon data
100
Experimental data at 55 MeV/nucleon
CH89 V = 0.70
d/dR
80
Curve 1
60
40
20
0
0
10
20
30
40
50
c.m(degree)
Curve 1: Optical model fitting
Curve 2: 12C+p OP
Physics Letters B 343 (1995) 53-58;
Using CH89 systematic OP to refit the
Angular distributions to get the exit channel OP
d(11Be,p)12Be Transfer reaction
Counts/500 keV
Proton coincident with 12Be
Isomeric mixed with 2+ and 1Mean=-2.14MeV
Sigma=0.65Me
Mean=0.22MeV
Sigma=0.5MeV
G.S
12Be
Energy(MeV)
Q-value
Angle(degree)
Isomeric state(E0 decay was used)
e+e- pair
creation
T1/2 = 331 ns
E2: 17%
130 keV and 2100 keV
Counts/ 30 keV
E0: 83%
511 keV
S. Shimoura et al., Physics Letters B 560 (2003) 31–36;
S. Shimoura et al., Physics Letters B 654 (2007) 87-91.
Energy(keV)
12Be
+ proton + gamma
Differential cross sections and SF
Isomeric state
Ground state
27A MeV
(DWBA)
5A MeV
(DWBA)[1]
2.8 A MeV
(DWBA)[2]
G.S
0.14+0.04-0.04
0.25+0.03-0.07
Isomer
0.24+0.08-0.08
0.73+0.27-0.40
0.15~0.25
0.32~0.95
Fresco input file is provided by D.Y.Pang
[1] ]Phys.lett.B 682,391,2010.
[2] Phys.Rev.C 88,044619,2013
Error： 68% confidence
G.S SF is in consistent with previous results
Isomeric state ‘s SF is inconsistent
01+ G.S
02+ Isomer
Inutruder
normal
intruder
G.S
Isomer
reference
norm
al
(1) G.S: only get s-wave SF, could not get d-wave and p-wave content.
Consistent with
s other
d experimental
p
s d p results within error bar
F.C.Barke
33
34
32
56
2
42 Dominant dominant J.Phys.G 36,038001,2009;
J.Phys.G 2, L45,1976
(2) Isomeric state: very small s-wave SF from experiment
H.T.Fortune
and theoretical
53
15 calculations
32
25 7 to
68see
dominant
Notconfiguration
Phys.Rev.Ccomponent
74,024301,2006; J.Phys.G
Need more
Intruder
R.Sherr
038002,2009;
Phys.Rev.C83,044313,2011.
C.Romero-Redondo
Three –body model
?
10- 13-19 1513
23
68
?
G.Blanchon pp-RPA
25
18.5
0
19 Not
M.Dufour
58
74
dominant
Not
Phys.Rev.C 77,054313,2008.
dominant Phys.Rev.C 82,034313,2010.
NCSM
16
59
no
Not
No data
Nucl.Phys.A 836,242,2010.
Knock -out reaction
68
32
no
dominant
No data
Phys.Rev.Lett 85,266,2000;
Phys.Rev.Lett 96,032502,2006.
no
60 dominant
Not
Phys.Rev.lett 108,122501,2012.
0.56
0.48
0.44
Charge exchange
reaction
no
no
25
Transfer reaction
0.28
no
no
0.73 no
no uncertainty dominant
0.15~0
.25
no
no
0.32- no
0.95
no uncertainty uncertainty Phys.Rev.C 88,044619,2013
0.14
no
no
0.24 no
no D-wave?
Our result
no
D-wave?
Phys.lett.B 682,391,2010.
Summary
 OP for 11Be+d are extracted from the same experiment
Global OP including 11Be density can reproduce angular distribution
Core excitation of 11Be is important
the effect of H percent in CD2 target are removed
 New experimental technical to detect isomeric state
implant----stop-----decay
get the angular distributions in smaller C.M system
 DWBA method is used to extract the s-wave SF
G.S : SF = 0.14+0.04-0.04, not in conflict with other experimental results
Isomeric state: SF = 0.24+0.08-0.08, Consistent with other experimental result
 ADWA calculations for these three sets data
 More theoretical calculations to explain our results
Intruder state
Normal state
Collaborators
Chen Jie, Ye Yanlin, Li Zhihuan, Li Qite, Ge Yucheng,
Jiang Dongxing, Hua Hui, Yang Zaihong, Sun Yelei,
Tian zheng yang,Li Jing, Jiang Wei, Zang Hongliang
Aoi, Ong Hooi Jin, Eiji Ideguchi, Tetsuya, Mana, Suzuki,
Tran Trong
Jenny lee, Wu Jin, Liu Hongna, Wen Chao
Pang Danyang
A.M.Moro
Test Results for PKU silicon detector
5.486 MeV
缺一张环形硅的测试图。
detected by
Energy spectrum of 241Am detected
by400 um Annular DSSD
5.443 MeV
Energy spectrum of
300 um DSSD
241Am
Energy resolution is about 0.5—0.6%
(FWHM).
Energy resolution is about 0.7—0.8%
(FWHM).
Dead layer is about 0.6 um silicon layer equivalence .
Provide by J.Chen
Time resolution of NaI(Tl) detector
OUT
NaI
ADC
N568B
trigger
FOUT
60Co
Plastic
CFD
CFD
delay
and
trigger
stop
TDC
start
Time resolution of NaI(Tl) detector is
about 1.7ns(FWHM).
The time signal will be recorded in the experiment, which will be used to identify
the delayed gamma events.
Give the uniform SF at different incident energies.
The decay from Ex = 2.68 MeV to 02+ , which can
not be distinguished from the direct population 02+ ,
can be ignored.
0.4%
99.6%
The gamma decay probability is proportional to
Er3, only 0.4% 1- state will decay to 02+ .
eq. 3C-16 of the Bohr Mottelson textbook.
Provided by Pro.Aoi-san
Therefore, we can reach our preliminary physical
goal with the thick target.
TOF (ns)
From Target CD2
From silicon detector
TDC: Common-stop mode
Proton: Most are from 0-degree
silicon detector
E(MeV)
PID in 0-degree telescope
10Be
11Be
PID with !(time cut)
12Be
4He
DSSD Energy
DSSD Energy
PID without proton-time cut
11Be
10Be
12Be
8Li
SSD1 Energy
PID with time cutCtarget
DSSD Energy
DSSD Energy
SSD1 Energy
PID with proton-time cut
4He
SSD1 Energy
SSD1 Energy
Carbon background
Without Carbon background
ΔE
ΔE
With Carbon background
Energy/MeV
Energy/MeV
Counts/100ns
T1/2 = 350(50) ns
T (ns)