3rd International Symposium On Nuclear Symmetry EnergyNSCL/FRIB,MSU, MI,USA, July 22-26

Experimental effort to study Symmetry Energy with the Cooling Storage Ring at Lanzhouwith the Cooling Storage Ring at Lanzhou

Zhigang Xiao

Tsinghua University, Beijing

N X (CCNU) S kNu Xu (CCNU) : Spokesperson Zhiyu Sun (IMP-CAS) : Beam Line/Dipole/ExperimentLei Zhao (USTC) : Read-out electronics/DAQL M Duan (IMP CAS) : For MWDC design assembling and testL. M. Duan (IMP-CAS) : For MWDC design, assembling and testYi Wang (THU) : TOFMing Shao(USTC) : TOFYuGang Ma Fei Lu (SINAP): TPCYuGang Ma, Fei Lu (SINAP): TPCXiang Ming Sun (CCNU) : Silicon Pixel Detector/ZDC

物 理 系

OutlineCEE

Pion probe to Esym(ρ) at ~2ρ0Machine and DetectorPhase I Experiment and

detector R&DOutlook

Esym(ρ) with π-/π+ ratio: Soft or Stiff ? CEE

Physics Letters B 683 (2010) 140–144PRL 102 (2009) 062502

Stiff

l iti itSoft

Physics Letters B 718 (2013) 1510–1514or loss sensitivity on γJun Hong, NUSYM13 Poster

Model Dependent PuzzleCEE

Theoretically:

Treating of pion is model dependent, other effects to be considered…

Theoretically:

Need to compare more pion related quantities, and more diagnostic spectra …

to achieve further understanding on pionproduction and transport in HIC

Not cite unpublished data

Diagnostics  ICEE

400 AM V8 fm/c 400 AMeV

10 fm/c 12 fm/c

• A soft EOS leads to a enhanced N/Z at high density  

Diagnostics IICEE

High density achieved in the central region, where a g de s ty ac eved t e ce t a eg o , w e e alarger N/Z asymmetry is experienced with a softer Esym(ρ).

Experimentally …CEE

More data at different beam energy Beam Energy Scan in sensitive regime

More Systems with rather sensitivityMore Systems with rather sensitivity

More data at different phase coverage Whole phase space comparison

Samurai TPC project (MSU/RIKEN)

and others ……

p j ( )

OutlinePion probe to Esym(ρ) at ~2ρ0Machine and DetectorPhase I Experiment and detector R&DOutlookOutlook

Introduction to HIRFL: Beam facilitiesCEE

N

SSC

SFC: ≤ 10 AMeV (H.I.), 17~35 MeV (p)SSC: ≤ 100 AMeV (H.I.), ≤ 110 MeV (p)

SFC

SSC ( ), (p)CSRm: ≤ 1000 AMeV (H.I.), ≤ 2.8 GeV (p)

CSRe

L2

RIB

LL

LL

1

CSRm

RIB

L

CSRIBLL1: RIBs at tens of AMeVRIBLL2: RIBs at hundreds of A MeVCSRe: storage ring with deceleration

Introduction to HIRFL: Exper. SitesCEE

CEE

HPLUS10

HPLUS

⑥ CEECEE – CSR External-Target Experiment

HIRFL‐CSR energy range is favoredCEE

48Ca+48Ca 1.40

124Sn+124Sn 1.48

197Au+197Au 1.49

CEE conceptual designCEE

Main ParametersCEE

Main Feature Designed Main Feature Designed

Emin 0 3 GeV/u Emax 2 8 GeV/u (p)Emin 0.3 GeV/u Emax 2.8 GeV/u (p)

Heaviest Sys. U+U Max. Rate 104 Hz

# Ch l 2*104 C >50%# Channels 2*104 Coverage >50%

P Resolution 5% Syst. Error 10%

Physics with CEECEE

1）Asymmetry nuclear EOS2）Reaction dynamics2）Reaction dynamics 3）Medium Effect ）4）Λ hyper-nuclei

5）N*

Possible ObservablesCEE

Isospin related observablesIsotope resolved phase space distribution

Isospin diffusion at high energyNucleon scattering by mean field Flow…

Elastic scattering and few body processHyper nuclei and N* research

Dipole concept CEE

Central Field 0.5 T

Field Dimension ~1 m×1 m×1.5 m3

Inhomogeneity 1%

Total Size ～2.5×3×4 m3

Total Weight 200 Ton

Prototype of a superconductive magnet(Made in IMP, for FAIR)

Silicon Pixel DetectorCEE

Wafel

ChipChip

Pixel Dimension：64x64

Pixel Size：Pixel Size：

80umx80 um

(TopMetal)

CCNU

MRPC – TOF concept  CEE

NormalHigh Gra.High Reso MRPC

High Count、High Gra High Reso

500M V 600M V 800M V

High Reso. MRPC High Gra. High Reso.

Momentum 500MeV 600MeV 800MeV

Pion

#1 56 47 45

#2 51 48 40sample #2 51 48 40

#3 46 48 45

#1 29 32 36Proton sample #2 28 30 35

#3 31 31 35

MWDC  ConceptCEE

Large Area MWDC array Structure:Three sense plane，Two arms, Six MWDCstotal area 12 m2total area ~12 m2.Expected Performance:R< 300 μm, MIPs Efficiency per layer >95%。

Area (W×H) 1280×1200 1440×1300 1760×1500

Sense Wires 416 464 560

Pieces 2 2 2

St t Φ20 W(A ) T i 60 WiStructureAnode Plane

Φ20μm W(Au) ，Tension 60g，Wire Distance10mm；

Field Wire Φ75μm Be-Cu，Tension 120gStructure Φ75μm Be Cu Distance 2mm TensionStructureCathode Plane

Φ75μm Be-Cu，Distance 2mm，Tension 120g；

Total Readout 2880 Total Area 12.1m2

MIP Efficiency η>96％(Single Layer)

Position Resolution

σ<300μm

TPC conceptCEE

Readout Are ~1.2 m× 0.9 m

# Ch l 11000 (110 100)# Channel ~11000 (110×100)

Paddle Size 9 mm × 9 mm

D ift l th 60Drift length 60 cm

Working Gas 90% Ar + 10% CH4

Fi ld 150V/Field 150V/cm

dE/dx  Range Z<=3, π,p,d,t,He‐Li

T k R l ti 2 5~3Track Resolution 2.5~3 cm

Max. Multiplicity 200

OutlinePion probe to Esym(ρ) at ~2ρ0Machine and DetectorPhase I Experiment and detector R&DOutlookOutlook

CEE Phase ICEE

TOF Wall

Neutron Wall

MWDC

Target

STARTSTART

Dipole

Whether The physics still there?CEE

Test BeamCEE

• C+C @ 200,600 MeV/u• Three MWPC tracking• 12 TOF Strips + Start• 1 Neutron Wall• Inclusive• Inclusive • B~0.4T，reversible

0/1 resolution4 mm wire distance

Test Experiment OutputCEE

12C+12C 600AMeV

Pπ+ Pπ+π-

Experiment: 600 MeV/u

Simulation: σMWPC=1.5 mm≈4/(12)0.5

1) Tracks reconstructed well, Pion ratio ~ 1 in C+C

2) Li it d l t i d t t l ti d di t b k d2) Limited electronics, detector resolution and dirty background …

3) Systematic error not controlled

MWDC  ParametersCEE

Three Layers，

0 and ±30° tilting。

Design and Manufactory of MWDCCEE

Soldering Wire and FrameWiring: × 。 Leak rate Test

Soldering Wire and FrameFrame=1.6m×1.6m。

Wire Frame/Tension Preset A Large MWDC to be completed

Installed for Beam Test

ElectronicsCEE

PXI based DAQ

Electronics test with MWDCCEE

300

400

ps)

250

300

350)

200

reso

lutio

n (p

150

200

250

h of

TO

T (n

s

0

100time

50

100wid

t

800full-energy peak

0 0.5 1 1.50

amplitude (V)0 100 200 300 400 500 600

0

input charge (mV)0.04

100%

)

400

600

ber

escape peak0 02

0.03

nt re

solu

tin (*

200

400nu

m

0.01

0.02

mea

sure

men

0 2000 4000 6000 80000

peak channel number

0 100 200 300 400 500 6000

input charge (mV)

char

ge m

Large MWDC Prototype TestCEE

Large MWDC Prototype TestCEE

0 9

1.0

y

100

103 )

0.8

0.9

ficie

ncy

η>97％ 10 gai

n(3

0.7

Eff η

1Effe

ctiv

e1550 1600 1650 1700 1750 1800

0.6

Sense wire voltage(V)1300 1400 1500 1600 1700 1800

1EVoltage(V)Sense wire voltage(V) g ( )

Large MWDC Prototype Test

0.5

0.6

mm

) track residual MW DC detector

0.4

olut

ion

σ(m

0.2

0.3

R

eso

1550 1600 1650 1700 1750 18000.1

Sense wire voltage(V)

Best Residue: σ=240μm @ 1700+ VBest Residue: σ=240μm @ 1700 V

Tracking Test with MWDC arrayCEE

Drift Length ResolutionCEE

SimulationsCEE

Digitization and Event DisplayDetector Construction

Geant 4 Simulation Framework Done

Track ReconstructionCEE

δP ~ 5%

Simulation: ITOF – Short flight lengthCEE

Typical flight length < 0.5m

Due to short flight length, TOF g g ,PID can’t extend the PID range of dE/dx much.

ITOF used as trigger detectors onlydetectors only

Momentum resolution / Flight Length effectsCEE

Y-axis: 3σ separation momentum limit

1. Forward momentum resolution: <5%

p

2. i-TOF for trigger only

To do nextCEE

1) Detector Array Installation

2) Online System extension

3) Integration of the whole system

4) Tests4) Tests ……

> 3 years’ work ! 3 years work !

OutlookCEE

The symmetry energy at supra-saturation density is of highscientific interest Large pushing effort both experimentallyscientific interest. Large pushing effort, both experimentallyand theoretically, is witnessed in China.A large spectrometer called CEE is being proposed atA large spectrometer, called CEE, is being proposed atHIRFL-CSR.A phase-I experiment is being built, with MWDC being theA phase I experiment is being built, with MWDC being themajor tracking detector.

1000 km ahead

Thank you!k y