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