Spectroscopic Study of the Intruder States in 12Be via (d , p)
Transfer ReactionChen Jie , Lou Jian-Ling, Ye Yan-Lin
Peking University, ChinaAugust 17, 2012
The halo nucleus 11Be
Neutron loosely bound Sn=0.504 MeVLarger radius rms= 2.91 fm Parity inversion : intruder state
10Be core + 1 valance n
0 s1/2
0 p3/20 p1/2
0 d5/2
0 d3/21 s1/2
PRC 85 (2012) 051303R
⑳
⑧1 s1/2 0 p1/2
0 d5/2
0+ × 1s1/2 2+ × 0d5/2
11Begs(1/2+)
2+
0 p1/2
Nearly 100% intruder state in 1 1Beg . s
PRL 108, 192701 (2012),10Be(d,p) S~0.71(5)
inversion
10Be Core excited to 2+
PLB 461, 22-27 (1999) 11Be(p,d) S~16%
PRL 84, 35(2000) 11Be 1n removalReaction , momentum distribution S~22%
[6]F. C. Barker, J. Phys. G 2, L45 (1976).
Intruder state
Normal state
12Be = 11Be + n
or
12Be• disappearance of conventional magic number : N=8• Isomeric state : 02
+ 331(12) ns
Two decay modes: E2 decay: 130 keV and 2.11 MeV gamma-rays 17(2)%E0 decay: internal conversion: negligible e+e- pair creation 511keV gamma 83(2)%
Physics Letters B 560 (2003) 31–36;
Physics Letters B 654 (2007) 87-91.
0 s1/20 p3/2
0 d5/2
0 d3/21 s1/2
0 p1/2
⑳
⑧1 s1/2
Normal Intruder state
12Begs(0+)
0 d5/20 p1/2
(0s)4(0p)8 0ћω (0s)4(0p)6(1s0d)2 2ћω
isomer
01+ G.S 02
+ Isomer G.S Isomer reference
Inutruder normal intruder normal
s d p 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 36, 038002,2009; Phys.Rev.C83,044313,2011.
C.Romero-RedondoThree –body model
? 10-13
13-19 15-23
6-8
? dominant Not Phys.Rev.C 77,054313,2008.
G.Blanchon pp-RPA 25 18.5 58 74 0 19 Not dominant
Phys.Rev.C 82,034313,2010.
M.Dufour 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.
Charge exchange reaction
no no 25 no no 60 dominant Not Phys.Rev.lett 108,122501,2012.
Transfer reaction 0.28 no no 0.73 no no uncertainty dominant Phys.lett.B 682,391,2010.
~0.20 no no 0.32-0.95
no no uncertainty uncertainty Phys.Rev.C 88,044619,2013
Ground state : transfer reaction could not give the clear result, are no conflict with others Isomeric state : transfer reaction contradict with Charge-exchange
No data: no data or no calculationNot: Intruder state is not dominantDominant: Intruder state is dominantUncertainty: no d-wave, could not make sure
Knock-out experiment(2ћω)78 MeV/u 12Be+9Be(s wave)
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) 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)
Phys.Rev.Lett 85,266,2000.
Phys.Rev.Lett 96,032502,2006.
Both are questioned by the mixture of isomeric state in the 1 2Be secondarybeam.
12B(1+)(7Li, 7Be)12Be( 2ћω)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)Two annular DSSDSelect s-wave ( abnormal )Identify the excited states of 12Be
01+ 0.28 ,
02+ 0.73 Intruder state dominate
Phys.Rev.Lett 108,122501,2012.
Phys.Lett.B 682,391,2010.
Phys Rev C 88,044619,2013
Discriminate isomeric states from ground state
1. 01+ : normalization,
unsure deuterium content
2. 02+ : Mix with 2+ state.
separate them incorrectly
Normalization factor for beam.
Phys.Rev.C 85,051303(R),2012.
Questioned by H.T.Fortune and R.Sherr.
Incident energy is about 2.8 MeV/nucleonTarget thickness: 1.0 mg/cm^2No 0-degree detectors due to higher beam intensityThick target and Gamma detectors to discriminate the excited states of 12Be.
(1) For 01+: no coincidence with 12BeLarger background
(2)For 02+Larger C.M angles
(3)target :H Percent(larger)
(4) No elastic scattering dataFor 11Be+d and 12Be+p
01+ , SF = 0.15~0.25 ;02+ , SF = 0.32-0.98.
G.S SF = 0.15 ~ 0.25Isomeric : SF = 0.32 ~ 0.95 .
OPs of entrance channel (11Be+d) and exit channel (12Be+p) affect SF extraction largly.
Goal of the proposed experimentMain 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
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)
Measure the elastic scattering Channel at the same experiment
Kinematics
Experimental Setup
Tele0Tele2
Tele1Annular DSSD
Beam
NaI
Beam :
Primary beam: 13C Intensity: 800 enAEnergy: 57.7 MeV/u Secondary beam : 11Be Intensity at F3: 1.5*10^4pps On zero Tele:
2.0*10^4ppsPurity: 90%--93% Energy: 27 MeV/nucleonContamination: mainly 9Li Beam time: 10 daysEnergy dispersion: 2%
Beam11Be
10Be
9Li
8Li
11Be
9Li
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 protonPID on the zero degree telescope
Kinematic loci for protons in coincidence with 11Be on Tele0
Energy spectrum for 11Be
cut 11Be on Tele0
cut 10Be on Tele0
Solid angle---Geant4 simulation
60 65 70 75 80 85 900.0001
0.001
0.01
0.1
ADWA method :Provide the OPOf entrance channel
Systematic is good.Need normalizationFactor
Prelim
inary
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.MoroDCE: dynamic core excitationG0: OP-N Gaussian potential fitting deuteron 3s1 phase-shiftsBX: deformed n+10Be (particle-rotor model of Nunes et al)CDCC: Continuum discreted coupled channelXCDCC: Extended CDCC
Core excitation is important
Prelim
inary
with core
excitation
Without core
excitation
11Be elastic and inelastic scattering on deuteronPID on the zero degree telescope energy spectrum for 11Be
cut 10Be on Tele0
cut 11Be on Tele011Be
10Be
Energy/MeVEnergy in SSD/MeV
Energy in
DSSD / a
rtificial u
nit
Provide by D.Y.Pang and J.Chen
Global JLM potential can reproduce the Angular distribution of 11Be+d
DWBA: provide 11Be+d OP
Provide by A.M.MoroNeed more discussion
Prelim
inary
[1] PRC 83, 064619 (2011)
[2] JPG 39 (2012) 095101
H in CD2 target (9.5%)
dh
Angle of 11Be(degree)
An
gle
of
deu
tero
n(d
eg
ree)
Angle of Deuteron(degree)
En
erg
y of
deu
tero
n(M
eV
)E
nerg
y of
deu
tero
n(M
eV
)
Angle of Deuteron(degree)Q-Value(MeV)
Cou
nts
d
dH
H
Prelim
inary
OP of the exit channel
We need 51 MeV/nucleon data
Physics Letters B 343 (1995) 53-58;
Curve 1: Optical model fittingCurve 2: 12C+p OP
0 10 20 30 40 500
20
40
60
80
100 Experimental data at 55 MeV/nucleon
CH89 V = 0.70
Curve 1
d/d
R
c.m(degree)
Using CH89 systematic OP to refit the Angular distributions to get the exit channel OP
Transfer reaction
Proton coincident with 12Be
Angle(degree)
En
erg
y(M
eV
)
Mean=0.22MeVSigma=0.5MeV
Mean=-2.14MeVSigma=0.65Me
Q-value
Cou
nts
/500 k
eV
12Be
G.S
Isomeric mixed with 2+ and 1-
Prelim
inary
Experimental Setup
Tele0Tele2
Tele1Annular DSSD
Beam
NaINaI(Tl) + PMTHigh-voltage affects gainGain varies with time
Peak channel varies with time
80 100 120 140 160 180 200 220 240 260 2802220
2240
2260
2280
2300
2320
2340
Open chamber
Open chamber
Time(File number)
Peak c
han
nel
Before
after
11Be beta-decay
Energy(keV)
Cou
nts
/10keV
Cou
nts
/30keV
Resolution become better
Prelim
inary
Isomeric state(E0 decay was used)
T1/2 = 331 ns
E2: 17%130 keV and 2100 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.
e+e- pair creation
Gamma+ proton + 12Be
Mean= 528keVSigma= 24.8keV
Energy(keV)
Cou
nts
/ 30
keV
Prelim
inary
Half-life of isomeric stateProton ( around 2MeV in Q_value ) + 511keV gamma
T (ns)
T1/2 = 350(50) nsCou
nts
/100n
s T ½ = 331 (12) nsPLB 560 (2003) 31–36;
PLB 654 (2007) 87-91. Prelim
inary
Differential cross sections and SF
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 0.15~0.25
Isomer 0.24+0.08-0.08 0.73+0.27
-0.400.32~0.95
Fresco input file is provided by D.Y.Pang Error : 68% confidence G.S SF is in consistent with previous
resultsIsomeric state ‘s SF is inconsistent
Prelim
inary
[1] ]Phys.lett.B 682,391,2010.
[2] Phys.Rev.C 88,044619,2013
Ground state
Isomeric state
01+ G.S 02
+ Isomer G.S Isomer reference
Inutruder normal intruder normal
s d p 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 36, 038002,2009; Phys.Rev.C83,044313,2011.
C.Romero-RedondoThree –body model
? 10-13
13-19 15-23
6-8
? dominant Not Phys.Rev.C 77,054313,2008.
G.Blanchon pp-RPA 25 18.5 58 74 0 19 Not dominant
Phys.Rev.C 82,034313,2010.
M.Dufour 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.
Charge exchange reaction
no no 25 no no 60 dominant Not Phys.Rev.lett 108,122501,2012.
Transfer reaction 0.28 no no 0.73 no no uncertainty dominant Phys.lett.B 682,391,2010.
0.15~0.25
no no 0.32-0.95
no no uncertainty uncertainty Phys.Rev.C 88,044619,2013
Our result 0.14 no no 0.24 no no D-wave? Not
(1)G.S: only get s-wave SF, could not get d-wave and p-wave content. Consistent with other experimental results within error bar
(2)Isomeric state: very small s-wave SF from experiment, small d-wave content from theory, so intruder states might not dominate.
consistent with other experimental results with error bar
SummaryOP 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 dataMore theoretical calculations to explain our
results
Intruder state
Normal stateor
Collaborators
Osaka University, Japan Aoi, Ong Hooi Jin, Eiji Ideguchi, Tetsuya, Mana, Suzuki, Tran Trong
RIKEN, JapanJenny lee, Wu Jin, Liu Hongna, Wen Chao
Beihang University, ChinaPang Danyang
Universidad de Sevilla, SpainA.M.Moro
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
Peking University, China
Thank you for attention!
Test Results for PKU silicon detector
5.486 MeV
5.443 MeV
Energy spectrum of 241Am detected by300 um DSSD
Energy resolution is about 0.5—0.6%(FWHM).
Energy spectrum of 241Am detected by400 um Annular DSSD
Energy resolution is about 0.7—0.8%(FWHM).
缺一张环形硅的测试图。
Dead layer is about 0.6 um silicon layer equivalence . Provide by J.Chen
Time resolution of NaI(Tl) detector
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 identifythe delayed gamma events.
60Co
NaI
Plastic
CFD
N568B
OUT
FOUT
ADC
delay
and
trigger
CFD
TDCstart
stoptrigger
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.
The gamma decay probability is proportional to Er3, only 0.4% 1- state will decay to 02
+ .
99.6%
0.4%
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.
E(MeV)
TO
F (
ns)
From silicon detector
From Target CD2
TDC: Common-stop modeProton: Most are from 0-degree silicon detector
11Be10Be
12Be
4He
8Li
PID with proton-time cut
11Be10Be 12Be
4He
DS
SD
En
erg
yD
SS
D
En
erg
y
SSD1 Energy
SSD1 Energy
PID without proton-time cut
DS
SD
En
erg
y
SSD1 Energy
PID with !(time cut)
SSD1 Energy
DS
SD
En
erg
y
PID with time cut-Ctarget
PID in 0-degree telescope
Carbon background
With Carbon background
Energy/MeV
ΔE
Energy/MeV
ΔE
Without Carbon background
Prelim
inary