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 !
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