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E07 experimentSystematic Study of Double Strangeness System

with the Emulsion-counter Hybrid Method

Current StatusKazuma Nakazawa

Phys. Dept., Gifu Univ., JAPAN

Outline1. Experimental motivation for double hypernuclei2. Status of the E07 experiment

Beam, Beam line (& KURAMA) Spectrometer, Hyperball-X, SSDs, Emulsion stack mover,Emulsion handling, Scanning system

3. Summary

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Study of hadron-hadron interactionSt

rang

enes

s s = -∞[N-Star/Strange Matter]

( )( )

NAGARA event

Baryon octet ・N-N interaction

Continuous research in experiment and theory for more than 50 years

・ Y-N interactionwhere Y = (Σ, Λ)

Steadily Progressing

Study of ・Λ-Λ interaction・Ξ-N interaction

Next subject

One of the most powerful methods for the detection of D.H.N.→ Emulsion experiment !!

Nuclear Chart with Strangeness

Unstable NuclideStable Nuclide

1. Experimental motivation for study of double hypernuclei

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in ~80 Ξ- stopsKEK-E176 KEK-E373

~ 2 x 104 Ξ- tracks (followed)

S.Aoki et al., NP. A828 (2009) 191-232

~ 103 Ξ- stops

NAGARA

Ξ -

MIKAGE

Ξ -

HIDA

Ξ -

Ξ -

Ξ -

M.Danysz et al., PRL.11(1963)29;R.H.Dalitz et al., Proc. R.S.Lond.A436(1989)1

in ~4 Ξ- stops

List of double hypernuclei

4 D.H.N in 7 samples by E373

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summarized in PHYSICAL REVIEW C88, 014003(2013) J.K.Ahn et al.

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Experimental motivation

＊Detection of double hypernuclei・ 10 times’ statistics of E373 (KEK-PS) 104 Ξ-stop

~102 double hypernuclei,~10 identification of nuclide.

・ Nuclear (A) dependence of ΛΛ binding energy.・ Making S = -2 nuclear chart.・ H-dibaryon.・ Ξ-N interaction via twin hypernuclei.

＊Measurement of X ray from Ξ-atom・ Ξ-N interaction.

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2. Status of the E07 experimentE07 collaborators

aJapan Atomic Energy Agency (JAEA), Japan,bPhysics Department, Gifu University, Japan,

cDepartment of Physics, Tohoku University, Japan,dAligarh Muslim University, India,ePusan National University, Korea,

fDepartment of Physics and Astronomy, University of NewMexico, USA,gBrookhaven National Laboratory, USA,

hUniversity Colledge of London, UK,iDepartment of Physics, Kyoto University, Japan,

jCIAE, China Institute of Atomic Energy (CIAE), China,kDepartment of Physics, Toho University, Japan,

lKEK, High Energy Accelerator Research Organization, Japan,mDepartment of Physics, Nagoya University, Japan,

n Gyeongsang Nat'l University, Korea,oSeoul National University, Korea,

pResearch Center for Nuclear Physics (RCNP), Japan,qMandalay University, Myanmar,rAdanabon University, Myanmar,

sUniversity of Fukui, Japan,tShanxi Normal University, China.

K.Imaia, K.Nakazawab, H.Tamurac, S.Ahmadd, J.K.Ahne, B.Bassalleckf, R.E.Chrieng, D.H.Davish, H.Ekawai, Y.Y.Fuj, S.Fukunagak, Y.Hanf, R.Hasand, S.Hasegawaa, E.Hayatai, M.Hirosei, K.Hoshinob, K.Hosomia, S.Hwanga, M.Ieiril,

K.Itom, K.Itonagab, T.Kawaim, J.H.Kimn, S.Kinbarab, R.Kiuchio, T.Koikec, H.S.Leee, J.Y.Leeo, C.Lij, Z.M.Lij, A.Mishinab, K.Miwac, H.Noumip, S.Ogawak, S.Y.Ryue, H.Sakoa, S.Satoa, T.Satom, M.Sekimotol, H.Shibuyak, K.Shirotorip, M.K.Soeq,

H.Sugimuraa, M.Sumihamab, H.Takahashil, T.Takahashil, K.Tanidao, K.T.Tintr, A.Tokiyasup, D.Toveeh, M.Ukaic, K.Umeharab, T.Watabem, T.Yamamotoc, N.Yasudas, C.S.Yoonn, J.Yoshidab, T.Yoshidas, D.H.Zhangt, J.Zhouj,

S.H.Zhouj, and L.H.Zhuj

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K1.8 Beam Line @J-PARC

Beam Line Spectrometer

KURAMA Spectrometer

EmulsionSSDGe array

Diamond Target

QQDQmagnets

KURAMAmagnetcollimator

K-

K+

Ξ-

2. Status of the E07 experimentE07 setup

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2. Status of the E07 experimentK- beam

E13 commissioning run (May 2013)Results

MR : 15kWK mom : 1.8 GeV/cK intensity : 170k/spill K/All ~ 70%

230k/spill K/All ~ 40%

beam : K/All ~0.86, 3x105K/spill 4.8 sec. cycle

total K- : 1.1 × 1011

In proposal for 104 Ξ- stop

Enough intensity and purityfor data-taking,

Further beam tunning and parameter optimization gives better performance.

emulsion gel : 2.6 t => 2.1 t ==×0.81KURAMA gap: 50 cm => 80cm ==×1.25

changed from proposal

Yield : same as proposal

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15kW 24kW 50kW(?)

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2. Status of the E07 experiment

Beam line spectrometer

K1.8 Beam Line@J-PARC hadron hall

・MagnetsQQDQ(Q)

・Momentum resolutionΔp/p = ~10-4

・Chambers, counters, etc.almost already been equipped

・Fabricating some counters.BAC etc. finish soon

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2. Status of the E07 experimentHyperball-X

・Clover-type detector 6 units1 unit with 4 Ge crystals

・veto BGO12 BGOs around 1 unit

・Photo peak eff. : 3% @ 350keV

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・Frame design has been done. R&D for LSO calibration system & etc.be ready by existing systems on Mar. 2014.By upgrading as possible Aug. 2014

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Figure 16. Circuit board withdummy sensors and pitch-adapters.

2. Status of the E07 experimentSSDs

・DSSD (in proposal) Prototype sensors (2010) test poor performance (2012) bought ready-made SSDs (Jan. 2013)

Nbulk, t = 320μm, Size 9cm×9cm Pitch : 50μm, 1792ch (use 1536ch) Leak current ： 3μA (max) Bias Voltage ： 50～120V

・SSD Characteristics

・Cosmic ray test

Position

Cosmic ray pulse・Prototype detector (Oct. 2013)・Stacking 4 sensors (Nov. 2013)・Fabrication (Dec. 2013)・Readout check (by Mar. 2014)

AD

C

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2. Status of the E07 experimentEmulsion handling

・Room request (in proposal) Gel pouring, drying, sheet cutting, development Building in Gifu Univ. [100 m2] (2012)

Plate stacking room [~10 m2] request in J-PARC site

Drying room

Development room withthree 1200 liters’ tanks.

Pouring room andemulsion sheet cutter.

・Emulsion gel amount (changed from proposal)2.6 t 2.1 t (by budget limitation)However, the expected yield is not changeddue to the wider KURAMA gap. (discussed in K- beam)

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#ofcosmicrays(/0.1x0.1mm2 )

Days after plate making

○: Refrigerator in Gifu Univ.□: In lead box at SK×: Out of lead box at SK

Cosmic rays in the emulsion#

of C

ompt

on e

lect

rons

(/10

-3m

m3 )

3

2

1

0 0 1 2 3(x102)

(x102)

Days after plate makingCompton electrons in the emulsion

10

8

6

4

2

0 0 1 2 3 4 5 6 7 (x102)# of

Cos

mic

rays

( / 0

.1x0

.1 m

m2 )

Days after plate making

=> 105 /cm2 = 10% of exposure limit

2. Status of the E07 experimentEmulsion handling --2

・Emulsion plate makingcan be done by the end of March 2014. we postponed the final day by three months.

・Lead blocksTo avoid exposure of Compton electron and cosmic rays,all of plates are stocked in a box of lead blocks at the SKuntil K- beam exposure.

We need ~102 blocks by Jan. 2014. (~300 blocks from ICRR)

Results of E373 (KEK-PS)

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2. Status of the E07 experimentKURAMA Spectrometer

D3 (AIDA chamber) D2 (KL chamber)KURAMA Magnet

・KURAMA MagnetGap 50 cm 80 cm …… done by KOTO Gr.Ξ- stopping x1.25

・TOF wallunder fabrication.

・Chambersreadout test is on-going.

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3-dimensional image taking with NON-stop stage driving.

New piezo system CMOS CameraBaumer HXC20

UNIOPT Co., Ltd.Piezo ActuatorMIPOS600GD w/ Obj. lenz

Alpha decay in the emulsion (up);its detection by Image recognition(down).

2. Status of the E07 experimentScanning systems

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Present New

Obj. Lens ×50 (NA. 0.9) ×20 (NA. 0.35)

Camera 100Hz XC_HR300 800Hz HXC20

Pixel 512×440 pixel 2039×357 pixel

Area 130 mm×110 mm 1140 mm×200 mm

Rate(Hz) 0.3 5

Present system

130 μm

110

μm

200

μm

1140 μmNew system with piezo stage

Images of all of the emulsion plates can be obtained in a few years.

2. Status of the E07 experimentScanning systems --2

5 sets 2 sets in Gifu1 set in Korea and Toho

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#A#B

#13

#16

#15

#14

#12

range (μm)

#A 4.2 ± 0.1

#12 >11.3mm

#B 2.9 ± 0.1

#13 370.5 ± 2.8

#14 1452.7 ± 6.4

#15 1029.7 ± 1.9

#16 107.5 ± 2.7

2. Status of the E07 experimentScanning systems --3

Double Hyper. cand. (Track #A) from 106 pictures

Superimposed image

Double HYP.

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3. Summary＊For the E07 experiment

to study S = -2 systems,preparations on ( installation on Feb., 2014 ; in original plan)

K- beam ……. seems enough intensity and purity, further tuningbeam line spectr. ….. almost all has been setHyperball-X ... frame design was completed, ready in Apr. 2014SSDs ……….. be ready by the end of Jan. 2014Emulsion …… handling by the end of Mar. 2014 ~102 lead blocks are necessary!! (should be looked for)

KURAMA spectr. …… be ready in a few monthsScanning systems …. be ready in a few monthsThe E07 experiment will be ready

in April, 2014 (by using existing systems)or in Aug., 2014 (by upgrading existing systems)

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