A New Spectrometer in RIBF-- SAMURAI --

Ken-ichiro YONEDARIKEN Nishina Center

Carpathian Summer School 2012, June 24 – July ７ , 2012

SAMURAI -- broadband spectrometer in RIBF --

Superconducting Analyzer for MUlti-particle from RAdio Isotope Beam with

7Tm of bending power

RI beamfrom BigRIPS

target

superconductingcoil

pole(2m dia.)

rotate

vacuum chamber

Kinematically complete measurements by detecting multiple particles in coincidence

Superconducting Magnet3T with 2m dia. pole (designed resolution 1/700)

80cm gap (vertical) Heavy Ion Detectors Proton Detectors Neutron Detectors Large Vacuum Chamber Rotational Stage

Invariant Mass MeasurementMissing Mass Measurement

ProtonHeavy Ion

Neutron

ZeroDegree

(old)

RRC

RILAC

RIPS

RARF

ZeroDegree

SAMURAI Here

History & Current Status of SAMURAI

• 1997 ? Design study started• …• Dec 2007 budget announcement

– 1.5B Yen, FY2008-2011

Magnet, detectors,… fabricated

• Oct 2010 – on-site magnet construction started

• Jun 2011 – designed maximum magnetic field attained

• Feb 2012– Detectors, cabling, vacuum, everything done

Mar 2012 commissioning May 2012 1st series of experiments carried out

Spokesperson Prof. T. Kobayashi (Tohoku) Co-spokesperson Prof. T. Motobayashi (RIKEN) Project Manager KY(RIKEN)

Large acceptance

0m-5m 5m 10m 15m

BeamlineTriplet Q

wall

Rotatablebase

magnetneutron hodoscope +10o

+5o

-5o

-10o

-15o

Pit

target

Beam linedetectors

A/Z=10.73GeV/c

A/Z=21.45GeV/c

A/Z=32.2GeV/c

trackingdetector

TOF

RI beam

plan view ZT=-4m

Vacuumchamber

wall

+5o

-5o

0m-5m 5m 10m 15m

BeamlineTriplet Q

Rotatablebase

neutron hodoscope

Pit

target

Beam linedetectorsRI beam

side view ZT=-4m roof

trackingdetector

TOF

Large momentum byte Rmax / Rmin ~ 2 – 3 (magnet rotatable)

Large angular acceptance for neutron, vertical – 5 degrees horizontal – 10 degrees (~100% coverage

up to Erel ~ 3MeV, ~ 50% coverage

at Erel ~ 10 MeV)

Photos ~magnet construction~

Rails for rotatable base Rotatable base with the first layer

Magnet yoke with poles

Coils with cryostats, LHe vessels

Vacuum chamber COMPLETED MAR 2011

SAMURAI Current View

Various Configuration

(, n) reaction: neutron-rich side (, p) reaction: proton-rich side (p,p’), (p,2p), (p,pn), …

pol. d-induced reaction EOS measurement

Various usage Variety of physics subjects covered with SAMURAI

SAMURAI allows versatile usage

Invariant Mass Spectroscopy

Invariant Mass M

A

Target

b Incident beam

A

A*

a

A*

a+b

Aa+b

22 )()( baba PPEEM

)( barel MMME

Excitation Energy

Coulomb Breakup – 1n Case

Non energy-weighted sum rule

1 2 3 4Excitation Energy (MeV)

0

0.5

1.0

dB(E

1)/d

Ex(

e2 fm

2 /M

eV)

T. Nakamura et al.,PLB 331,296 (1994)N. Fukuda et al.,PRC 70,054606 (2004)

Huge Strength appearsat low Ex(usually <10-3)

signature of halo structure

23

4

3)1()1( r

A

ZedEx

dEx

EdBEB

H. Esbensen et al.,NPA 542,310 (1992)

fmr 16.077.52

Coulomb Breakup – 2n Case

T. Nakamura et al.,PRL 96, 252502 (2006)

B(E1) = 1.42±0.18 e2fm2

11Li+Pb

221

2

)(4

3)1( rr

A

ZeEB

)cos( 12212

22

1 rrrr

Extraporated B(E1) 1.78(22) e2fm2

<θ12>= 48+14deg-18

NOT 90 deg !!

(, n) reaction: neutron-rich side

Detector System (, n) measurement mode

NEBULA

Detectors for Heavy Ion

• Detectors for Heavy Ion• Position measurement

• Drift Chambers Beam / Fragments

• Charge measurement• Ion Chambers Beam / Fragments

• Velocity measurement• Plastic hodoscope• Cherenkov counter

• Total E measurement• Pure CsI detector

• NEBULA• Plastic scintillator

• 240 modules• Effective Area: 3.6 m (H) × 1.8 m (V)

~ 100 % coverage @ Erel < 3 MeV ~ 40 % coverage @ Erel ~ 10 MeV

• Efficiency ~ 66 % (Half: ~40 %)

Half volume is ready in summer 2010.

All detectors are ready in 2011.

Pb target

Commissioning in March 2012

• Start all detectors, DAQs, with beam• Beam transport to SAMURAI• Heavy ion detectors optimization• NEBULA calibration

– Time-zero with high-energy gamma– Efficiency measurement (inc. 2n cross talk)

with 7Li(p,n) reaction

• Brho scan• HI-neutron coincidence measurement

– 17C 16C+n 15B+n– 15C 14C+n– 14Be12Be+2n

Everything worked fine !!

Resolution check

Goal resolution R/R achieved

Plots byDr Isobe

Brho scan @ 3T

Day-One Experiments

• “Spectroscopy of unbound oxygen isotopes”– Spokesperson: Yosuke Kondo (Tokyo Tech)– Observation of unbound oxygen isotopes

• “Exclusive Coulomb Breakup of neutron drip-line Nuclei” – Spokesperson: Takashi Nakamura (Tokyo Tech)– Coulomb breakup of neutron-rich boron and carbon isotopes

• “Structure of 18,19B and 21,22C”– Spokesperson: Nigel Orr/Julien Gibelin (LPC-Caen)– Observation of unbound states in neutron-rich boron and carbon

isotopes

•May 5 – 28, 2012, successfully done

•Now data analysis ongoing

Various Configuration

(, n) reaction: neutron-rich side (, p) reaction: proton-rich side (p,p’), (p,2p), (p,pn), …

pol. d-induced reaction EOS measurement

SAMURAI allows versatile usage

READY !!

Commissioned in March ’12

DAY-ONE exps in M

ay ‘12

Various usage Variety of physics subjects covered with SAMURAI

Nucleosynthesis in p-rich region: rp-processNucleosynthesis in p-rich region: rp-processVery hot, dense environment Very hot, dense environment

such as nova, such as nova, -ray burst-ray burst Hydrogen burningHydrogen burning proton captureproton capture

decaydecay

sequentially to produce sequentially to produce

heavier elementsheavier elements

Important to understandImportant to understandnatural abundancenatural abundance （（ esp. p-nucleiesp. p-nuclei ））cosmic cosmic -rays-rays from from

　　　　　　 ongoing nucleosynthesisongoing nucleosynthesis

Energy production in starsEnergy production in stars

……....

Need proton capture cross section of unstable nucleiNeed proton capture cross section of unstable nucleiNe novaM.Wiescher et.al. Phil. Trans. R. Soc. Lond. (1998)

{

γ

23Al

High-Z target (Pb)

22Mg

p

23Al*

Incident beam

2222Mg(p,Mg(p,))2323AlAl 2323Al(Al(,p),p)2222MgMg2626Si(p,Si(p,))2727PP 2727P(P(,p),p)2626SiSi

~ 60nb~ 60nb ~ ~ 4mb4mb

23Al22Mg + p

Inverse reaction

Cross section far larger Detailed valance + virtual photons

Coulomb Breakup – 1p Case-- Inverse of (p,) reaction --

Resonant capture strength Resonant capture strength 2j+1

(2j1+1)(2j2+1)p

+p

23Al22Mg + p~

whenp

p

Determination of is importantIn Coulomb dissociation, measured excitation cross section

B(E2)

Resonant Capture-- Importance of --

==

0 1000 2000 3000 4000

Relative energy [keV]

Cou

nts

/150

keV

・ energy resolution 170 keV (Erel = 400 keV)・ identify reaction through the first excited state clearly.

continuum component: E1 , constant astrophysical S -factor

1st excited state(objective state)

Higher excited state

Cosmic γ-emitter

Ne novaM.Wiescher et.al. Phil. Trans. R. Soc. Lond. (1998)

0.1 0.2 0.5 1.0 2.0 T [GK]

106

104

102

100

ρ [

g/c

m3]

βdecay is favored

Which?

Nucleosynthesis in explosive hydrogen burning(Novae, X-ray bursts)

Nova Model M1 : J.Jose et al Astrophys. J. 520 347 (1999) M2 : C. Iliadis et.al. Astrophys. J. Supp. 142 105 (2002)

　　Coulomb Breakup in heavy regionCoulomb Breakup in heavy region　　　　 candidates of waiting point, bottle neckcandidates of waiting point, bottle neck

　　　　 understand origin of p-nuclei, natural abundanceunderstand origin of p-nuclei, natural abundance

RequirementsRequirements・ ・ Heavy elements productionHeavy elements production RIPSRIPS 　　 RIBF + BigRIPSRIBF + BigRIPS

・ ・ Improvement exp. resolutionImprovement exp. resolution Silicon Telescope Silicon Telescope

SAMURAI SAMURAI spectrometer spectrometer

resolution ~ 1/700 resolution ~ 1/700

up to up to 100100SnSn

Thielemann et al., Prog. Part. Nucl. Phys. 46 (2001) 5.

Coulomb Breakup in Ni - Sn regionCoulomb Breakup in Ni - Sn region

• Detectors for Proton• Proton Drift Chamber• Plastic Hodoscope

• Silicon Strip Detector• Broad dynamic range Both proton & heavy ion (Z < 50) hit the detector• Capability of high density

signal processing Signals of about 2500ch in total

Modify integrated ASD circuitHINP16C in collaboration with

Texas A&M, Washington Univ, Louisiana (TWL) collaboration

HINP16C --- 16ch processing in 1 chiptwo output for energy and timing

Detector System (, p) measurement mode

Detectors for Proton

(, p) reaction: proton-rich side

All detectors are ready in 2011.

Detectors for Heavy Ion

Silicon Strip Detector

Pb target

To be ready in 2013.

Various Configuration

(, n) reaction: neutron-rich side (, p) reaction: proton-rich side (p,p’), (p,2p), (p,pn), …

pol. d-induced reaction EOS measurement

SAMURAI allows versatile usage

READY !!

Commissioned in March ’12

DAY-ONE exps in M

ay ‘12

TO BE READY

in 2013

US-RIKEN collaboration

Various usage Variety of physics subjects covered with SAMURAI

Nuclear EOS Study by using TPC

Symmetry energySymmetry energy

/)( pn

2)()0,(),( symEEE

)0,()1,(),(

2

1)(

0

2

2

EEE

Esym

• Asymmetric system

• High density (e.g. ~20)

1: neutron star

} measurement required

Au+Au

?

MSU

RIBF

GSI

Isospin diffusion, n-p flow

Pion production

RIBF can constrain the symmetry energy at ~ 20.

Requires data with controlled variations in system asymmetry

RIBF can constrain the symmetry energy at ~ 20.

Requires data with controlled variations in system asymmetry

Xia

o, e

t al., a

rXiv:0

80

8.0

18

6 (2

00

8)

Re

isdo

rf, et a

l., NP

A 7

81

(20

07

) 45

9.

Asymmetric system 124Sn+132Sn(~0.24), @340AMeV(~20)

TPC+NEBULA JPN+US collaboration

Ready in 2014

Rigid Top PlatePrimary structural member,reinforced with ribs.Holds pad plane and wire planes.

Front End ElectronicsLiquid Cooled

Pad Plane (108x112)Used to measure particle ionization tracks

Field CageDefines uniform electric field.Contains detector gas.

Thin-Walled EnclosureProtects internal components, seals insulation gas volume, and acts as major structural member

Voltage Step-DownPrevent sparking from cathode (20kV) to ground

Target Mechanism

Calibration Laser Optics

beam

SAMURAI TPC: Exploded View

RailsInserting TPC into SAMURAI vacuum chamber

Proposed research program

• Typical rates at 104/s are 3-4 pions/s of each charge and about 5 n’s/s Goal is to run up to 105 /s

• Ideal would be to run 3-4 weeks/year. This corresponds to two experiments that each measure two pairs of systems: e.g. 132Sn+124Sn, 105Sn+112Sn at one incident energy.

Probe Devices Elab/A(MeV)

Part./s MainFoci

PossibleReactions

FY

+-,p, n,t,3He

TPCNebula

200-300350

104-105 Esym

mn*, mp*

132Sn+124Sn, 105Sn+112Sn, 52Ca+48Ca, 36Ca+40Ca124Sn+124Sn, 112Sn+112Sn

2014

+- p, n,t,3He

TPCNebula

200-300 104-105 nn,pp

np

100Zr+40Ca, 100Ag+40Ca, 107Sn+40Ca, 127Sn+40Ca

2015 -2017

Slide by T. Murakami

Various Configuration

(, n) reaction: neutron-rich side (, p) reaction: proton-rich side (p,p’), (p,2p), (p,pn), …

pol. d-induced reaction EOS measurement

SAMURAI allows versatile usage

READY !!

Commissioned in March ’12

DAY-ONE exps in M

ay ‘12

TO BE READY

in 2013

US-RIKEN collaboration

TO BE READY

in 2014

SAMURAI-TPC collaboration

(US-KYOTO-RIKEN)

Various usage Variety of physics subjects covered with SAMURAI

Various Configuration

(, n) reaction: neutron-rich side (, p) reaction: proton-rich side (p,p’), (p,2p), (p,pn), …

pol. d-induced reaction EOS measurement

SAMURAI allows versatile usage

READY !!

Commissioned in March ’12

DAY-ONE exps in M

ay ‘12

TO BE READY

in 2013

US-RIKEN collaboration

TO BE READY

in 2014

Tohoku-RIKEN TO BE READY

in 2014

SAMURAI-TPC collaboration

(US-KYOTO-RIKEN)

Various usage Variety of physics subjects covered with SAMURAI

Various Configuration

(, n) reaction: neutron-rich side (, p) reaction: proton-rich side (p,p’), (p,2p), (p,pn), …

pol. d-induced reaction EOS measurement

SAMURAI allows versatile usage

READY !!

Commissioned in March ’12

DAY-ONE exps in M

ay ‘12

TO BE READY

in 2013

US-RIKEN collaboration

TO BE READY

in 2014

Tohoku-RIKEN

Exps approved

Beaumel (Orsay)

Sakaguchi (Kyushu)

Sasano (RIKEN)

New Detector

MINOS (Saclay)

to be ready in 2014

TO BE READY

in 2014

SAMURAI-TPC collaboration

(US-KYOTO-RIKEN)

Various usage Variety of physics subjects covered with SAMURAI

Construction Members

Construction Team Member (*Leader)

Magnet and Infrastructure:

Vacuum system and Utilities:

Heavy ion detectors:

Y. Matsuda (Kyoto), K. Sekiguchi, N. Chiga, graduate students, T. Kobayashi* (Tohoku), H. Otsu (RIKEN)

Neutron detectors (NEBULA):R. Tanaka (Tokyo Tech), Y. Satou (Seoul National Univ.)

Proton detectors:

K. Yoneda*, Y. Togano, M. Kurokawa, A. Taketani, H. Murakami, T. Motobayashi (RIKEN), K. Kurita (Rikkyo), T. Kobayashi (Tohoku), L. Trache (Texas A&M) and the TWL collaboration

Polarized deuteron induced reaction experiment devices: K. Sekiguchi*, T. Kobayashi, Y. Matsuda, graduate students (Tohoku)

Time projection chamber:

H. Sakurai (RIKEN), W.G. Lynch (Michigan State) and SAMURAI TPC collaboration

In-House Work Force: Research Instruments Group (T. Kubo - Group Leader)

SAMURAI Team (T. Motobayashi*, H. Sato, Y. Shimizu, K. Yoneda)

T. Kobayashi (Tohoku) ・ SpokespersonT. Motobayashi (RIKEN) ・ Co-spokespersonK. Yoneda (RIKEN) ・ Project manager

H. Sato*, K. Kusaka, J. Ohnishi, H. Okuno, T. Kubo (RIKEN)

H. Otsu*, Y. Shimizu (RIKEN)

T. Nakamura*, Y. Kondo, Y. Kawada, T. Sako,

T. Murakami* (Kyoto), T. Isobe, A. Taketani, S. Nishimura, Y. Nakai,

Summary

• SAMURAI started working– Commissioning in March 2012– Day-One experiments in May 2012– All done successfully

• Extension of SAMURAI collaboration– Construction base Physics outcome

• We welcome your participationin SAMURAI collaboration !!

Thank you for your attention !Thank you for your attention !