RIBF experiments by usingRIBF experiments by using Ge detectors

Eiji IdeguchiEiji Ideguchi

CNS, University of Tokyo

CollaboratorsCollaborators• CNS E. Ideguchi, S. Shimoura, S. Michimasa, S. Ota, 

A Saito H Miya S GoA. Saito, H. Miya, S. Go• RIKEN N. Aoi, K. Yoneda, S. Takeuchi, M. Kurokawa, H. Baba, 

P. Doornenbal, H. Scheit, D. Steppenbeck, M. Matsushita, K Li H Wang T Kubo T Ohnishi H Takeda D KamedaK. Li, H. Wang, T. Kubo, T. Ohnishi, H. Takeda, D. Kameda, N. Fukuda, H. Sakurai, T. Motobayashi

• Kyushu T. MorikawaKEK N I i Y Hi YX W t b H Mi t k• KEK N. Imai, Y. Hirayama, Y.X. Watanabe, H. Miyatake

• JAEA M. Oshima, M. Koizumi, Y. Toh, A. Kimura, K. Furutaka, S. Nakamura, F. Kitatani, Y. Hatsukawa, H. Harada

Chib I t M S k• Chiba Inst.  M. SugawakraTech.

• KTH B. Cederwall, T. Bäck• ANL M.P. Carpenter, R.V.F. Janssens, S. Zhu• LBNL P. Fallon, R.M. Clark• Senshu M. Oi

IntroductionIntroductionPhysics cases

l d f i i i h l iAnomalous deformation in neutron‐rich nucleinew deformed region near N≈40 Cr nuclei

Prolate‐oblate shape coexistenceProlate‐oblate shape coexistenceNeurton‐rich Fe, Cr, Mo region

Deformed shell structures SD states in neutron‐ rich nuclei near 48Ca

Experimental methodLif i i R il Di M h dLife‐time measurements using Recoil Distance Method Experiment with fast RI beamDegraded beam at RIBF + Ge array (GRAPE Gretina/GRETA)Degraded beam at RIBF + Ge array (GRAPE, Gretina/GRETA)

Low‐energy Multiple Coulomb excitationFusion evaporation(Multiple neutron transfer)

Anomalous deformation in neutron‐rich nuclei

~64Cr

4034

4042Si ?

20 28 32Mg

2 6 816 20

12Be

Study of 60,62Cr• Recent study of 60,62Cr  by N.Aoi

et al.• (p p’) experiment at RIPS

Phys. Rev. Lett. 102, 012502 (2009)

• (p,p’) experiment at RIPS• New deformed region near 60Cr

– Deformation length δpp’g pp– Ex(2+), Ex(4+)– R4/2

• Shell model with GXPF1A• Shell model with GXPF1A– pf shell up to N=34– pf + gd N≧36

P. Adrich et al., Phys. Rev. C77, 054306 (2008)

B(E2) by life time measurements

Estimated 2ndary beam intensity by LISE++y y y67Co 68Co

1.40E-01 7.86.E-03Primary beam: 76Ge 345MeV/uIntensity : 30pnA 1.40E 01 7.86.E 03

64Fe 65Fe 66Fe 67Fe

1.38E+04 2.44E+04 1.18E+04 4.05E+0061 62 63 64 65 66

Intensity : 30pnAPrimary target: 9Be 2.2g/cm2

61Mn 62Mn 63Mn 64Mn 65Mn 66Mn

6.63E+03 6.36E+04 3.84E+04 1.06E+04 2.50E+03 1.70E-0259Cr 60Cr 61Cr 62Cr 63Cr 64Cr

3.48E+02 4.74E+04 1.65E+04 4.05E+03 5.97E+02 6.48E+0158V 59V 60V 61V 62V 63V

1 00E+00 4 41E+03 7 71E+02 1 03E+02 8 73E+00 3 54E 011.00E+00 4.41E+03 7.71E+02 1.03E+02 8.73E+00 3.54E-0157Ti 58Ti 59Ti 60Ti 61Ti 62Ti

9.81E+00 9.69E+01 9.00E+00 9.54E-01 1.83E-02 1.88E-0456Sc 57Sc 58Sc 59Sc 60Sc

1.65E-01 3.15E-01 2.68E-02 1.17E-03 1.74E-0555Ca 56Ca 57Ca 58CaCa Ca Ca Ca

3.33E-03 9.24E-04 4.20E-05 9.30E-07

Method of the experimentMethod of the experiment• Recoil distance method

v

D

τvDd eI /−=I I

Plunger deviceto be developedsoon

df II + If Id

Previous RDM measurement of 32Mgg

• Primary beam: 40Ar, 95MeV/u, 50pnA

• Secondary beam by using RIPS:32Mg 64MeV/u 1kpps 17%32Mg, 64MeV/u, 1kpps, 17%33Al(38%), 34Al(20%), 35Si(16%)

• Secondary target + degraderSpacer

Life time measurement by RDMGRAPE with BGO R400n, M.Suzuki et al. Space

Au degrader190mg/cm2

Au target1 35 / 21.35g/cm2

D = 0.6, 1.2, 5 mm

GRAPE (Gamma‐Ray detector Array with

18x2 segmented Ge

GRAPE  (Gamma Ray detector Array with Position and Energy sensitivity)

40

65 100

18x2 segmented Ge detectorsHigh Resolution

200 60

00High Resolution2.5 keV intrinsic resolution for 1.3 MeV

140

50

140

γHigh Sensitivity

Ω 5 % f 1 M V

267

222

εΩ ~ 5 % for 1 MeV γPosition Sensitive

Resolution of Doppler 60

Liquid Nitrogen Dewer

Resolution of Doppler Correction ~ 1 %

Goal: 1mm position resolution for z-direction

Block diagramFast Amp

Sum Ampp

Differentiation×2Pre Amp×9×2 TDC

Σ Ind. Zero crossdiS. Amp disc.

ADCGRAPE

Segment550 550 550

Central segment Side segments Corner segments

400

450

500

400

450

500

400

450

500

otal

Sum

250

300

350

-100 -80 -60 -40 -20 0 20 40 60 80 100

centerHistogram ID = 101

250

300

350

-100 -80 -60 -40 -20 0 20 40 60 80 100

sideHistogram ID = 102

250

300

350

-100 -80 -60 -40 -20 0 20 40 60 80 100

cornerHistogram ID = 103

T to

M. Kurokawa et al., IEEE Trans. Nucl. Sci. , 50(2003)1309 Ttotal – Tseg.

Pulse Shape AnalysisPulse Shape Analysis

β=0.3

Δz (σ) ~ 1.35 mm

GRAPE: DAQ upgradeDigital Signal ProcessingDigital Signal Processing

Sum AmpFast AmpDifferentiation×2Pre Amp TDCSum Amp Differentiation×2Pre Amp

Σ Ind. Zero crossdisc

TDC

GRAPE S. Ampdisc.

ADCGRAPE

Data taking system

Ge detector

Preamp out

Digital signal Processor

Digitized wave form data!digitized

Current

To get the digitized data, our group uses Digital Signal Processor.Signals from detector go into DSP, and are digitized by FLASH ADC.  Data are taken at 100 MHz sampling

Ge detector  Digital signal Processor Current

Data are taken at 100 MHz sampling. 

t

What is Moments?The 1st moment corresponds to the average of the pulse. 

f(t)

The 2nd moment corresponds to RMS.

<σ><σ>

<T><T>

tMoments include  characteristics of  pulse shape.

itusing these momentsusing these moments

p p

For digital pulse shape analysis we have to handle large

zz‐‐position?position?

For digital pulse shape analysis, we have to handle large amount of data  from FLASH ADC. But using a few parameter “moments” will extract the position.

S. Go et al. 

Simulation of 1st momentCorrelation between 

“T(sum)” vs

“T(hit)‐T(sum)” 

T( ) dT(sum) correspondsto the distance of electrodes.

T(hit) can split theinteraction point in thedetector “left” and

Each color dot corresponds to z‐position. Each curve shows (x y) points

“right”

curve shows  (x, y) points.  

Simulation data are given by    M. Kurokawa

Gamma ‐ray

1st moments from experimental data by using 22Na source. Events of Comptonscattering are selected. The data reproduce the consequence of simulation.

Experiment at RIBFGRAPE: RDMmeasurementGRAPE:  RDM measurementDALI2 :   new excited states, 

coincidence(GRAPE) 1% f 120°ε(GRAPE)～ 1% for 120 , 

～ 0.5% for 145°ε(DALI2)  ～ 10%

GRAPE DALI2

RI beams

GRAPE+DALI @ F8 of BigRIPS+ZDS lineGRAPE+DALI @ F8 of BigRIPS+ZDS line

Degraded beam at RIBF + Ge array g y(GRAPE, Gretina/GRETA)

Low‐energy Multiple Coulomb excitationLow energy Multiple Coulomb excitation→ High‐spin states→ Sign of Q moment by reorientation→ Sign of Q moment by reorientationFusion evaporation→ High‐spin states (SD band of 48Ca)→ High spin states (SD band of  Ca)Multiple neutron transfer, …

66F

Al 4.3g/cm2 Al 0.6g/cm2

76Ge (345MeV/u) + 9Be(2.4g/cm2) → 66Fe66Fe

g/ g/Energy:0～11MeV/u

Production of Low‐energy RI beamNuclear reaction : 46Ar(9Be,xn)55-xTi GRAPE (Gamma-Ray detector Array with

Position and Energy sensitivity

RIPS facility at RIKEN

Rotatable degraderAl 0.3mm

Wedge degrader

Plastic Scintillator

PPACsSuper conducted TripletQuadruple Magnet (STQ)

Clover Ge

Wedge degraderAl 0.6mm

F2 PPACSecondary target9Be 10um

Primary target9B 1 625

F1 PPAC

Beam energy

46Ar

48Ca primary beam63 A MeV

9Be 1.625mm

Secondary 46Ar beamBeam rate : ～1 Mcps@F3

purity : ～95%

Beam image50Beam energy

purity : ～95%0

-50

Doppler correction:2 PPACs before 2ndary target

→ Beam Image, incident angle on target

0-50 50 (mm)0 2 4 6 8 10(MeV/u)

F2 Plastic－F3PPAC TOF→ Beam Energy

GRAPE(CNS Ge Array, position sensitive)

Setup for Multiple Coulex. Exp.p p p

☞ ToF → EnergyPb target

PSD : 33°～ 83°9 ° 14 °F2 plastic － F3 PPAC

☞ PPAC1,2

97°～ 147°PPAC3: 0°～ 9°

→ Position, Angle on target☞ GRAPE or Gretina/GRETA

GRAPE→ γ ray measurement

• Deformed region β～0.3

F3F2

Ge Ge Ge

Target PSD

Deformed region β 0.3• B(E2) enhancement

～30 ：60Cr

PlasticAlR t t bl

PPAC1PPAC3

PPAC2

～100 ：102Mo

～200 ：168Dy• How high spin states can be Rotatable

Degrader Ge Ge Ge• How high‐spin states can be observed?

EndEnd