Study of light nuclei cluster structure with nuclear track emulsion

Denis Artemenkov VBLHEP, JINR EFB22-Krakow-2013

BECQUEREL at the JINR Nuclotron is devoted systematic exploration of clustering features of light stable and radioactive nuclei.

The fragmentation of a large variety of light nuclei was investigated using the emulsions exposed to few A GeV nuclear beams at JINR Nuclotron. A nuclear track emulsion is used to explore the fragmentation of the relativistic nuclei

.

Ongoing emulsion experiments

Experiments Country Area Gel weight (dry)

~30,000kg

Producer Film/ Gel

Film

Status Special requirements

OPERA experiment Internatio nal Japan 100,000 m 2 Fuji Produced Refreshing function.

Double Hyper nuclei a few 1000 kg 3 kg

Not decided

Gel Doing R&D For thick type emulsion Balloon cosmic-ray Japan 10 m 2 Fuji Film Produced Dark Matter Muon radiography single experiment.

~10 experiments Japan, Italy Bern, Italy, Japan a few m 2 /exp.

~ 50m 2 /total 1 kg (1-2 year) a few kg/exp Nagoya / to be done Fuji or Nagoya 15 kg/total Gel Film Doing R&D Produced or to be produced.

crystal size ~ 10nm Medical applications hadron therapy basic study beam study Proton radiography Dosimetry R&D Japan Bern Bern Bern 10 m 2 1 m 2 1 m 2 5 m 2 3 kg 0.3kg

0.3kg

1.5 kg Fuji / done Fuji / done Fuji / Film Film Film Film Produced Produced Produced Produced 3

12

C→3α

4

12

C



3



, 3.65 A GeV (PAVICOM image)

5

http://neutrontech.ru

12

C(n,n’)3α, E

n

= 14.1 MeV

DVIN - explosives detector on the basis of fast tagged neutron method for complex program for population safety in transport 3α (~3-5 ) μm

8 Be, 2 + -?

8 Be, 0 +

M

2 

Q

2     2 

m

2 

M

2   

E

 1

E

 2 2 

m

 

p

 1

p

 2 cos(  12 )   1 2 6

9

Be→2α

(1.2 A GeV)

7

8

Opening angle distribution of two α-particles

9 Be  2   9 Be Θ 

Θ, mrad <Θ>, mrad σ Θ , mrad

Fraction (Events)

Θ n (0 - 10.5) Θ w (15.0 – 45.0) 4.4 ± 0.2

27.0 ± 0.6

2.1 ± 0.2

5.9 ± 0.6

0.56 ± 0.04 (164) 0.44 ± 0.04 (130) Fractions of events Θ

n

and Θ

w

demonstrate compliance with weights 0 states of a

8

Be core, adopted in the two-body model, ω

0+

= 0.535 and ω

2+ +

and 2

+

= 0.465 [1,2]. They indicate the presence of these states as components of the ground state of the

9

Be nucleus.

1. Y. L. Parfenova and Ch. Leclercq-Willain, «Hyperfine anomaly in Be isotopes and neutron spatial distribution: A three-cluster model for 9 Be», Phys. Rev. C 72, 054304 (2005).

2. Y. L. Parfenova and Ch. Leclercq-Willain, «Hyperfine anomaly in Be isotopes in the cluster model and the neutron spatial distribution», Phys. Rev. C 72, 024312(2005)

9

10

C→2α+2p

(1.2 A GeV)

10

10 C

∑Z

fr

N

ws

N

tf

2He + 2H 159 211 He+4H 16 76 6H 8 16

11

10 С → 9 В+

р

→ 8 Ве+2

р (25-30%)

12

Modeling of 10 C fragmentation with Geant4

Model (CHIPS)

10

C



Em

 2   2

p

Experiment

Q

2  

M

2   2 

m

 13

7

Be→α+

3

He (2

3

He)

7

Be→

6

Be→α+2p

(1.2 A GeV)

14

7 Be  2He

He 7 Be

Channel 4 Не+ 3 Не n b =0 32 2Не n b >0 24 3 Не+ 3 Не 14 9 Total event number 56 23 12 C  7 Be ( 12 N+ 10 C+ 7 Be at 1.2 A GeV, 2006 ) 7 Li  7 Be ( 1.2 A GeV, 2004)

The coherent dissociation of

7

Be nuclei is mainly attributable to two-cluster structure

3 He + 4 He. 3

He clusters contribution is twice of the

4

He one, indicating the strong manifestation of

3

He clustering in relativistic processes. This type of clustering is most pronounced in channel

4 He +

dissociation of

7

Be nuclei, not accompanied by the emission of neutrons

3

He in coherent

( 12 N+ 10 C+ 12 7 C  7 Be Be at 1.2 A GeV) 2006 7 Li  7 Be (1.2 A GeV) 2004

Q

4

He

 3

He



M

4

He

 3

He



m

4

He



m

3

He

 1 , 59

MeV

7 Be 7 Be 7 Be



He+2H H He H 7 Be



6 Be+n



4 He+2 1 H+n 6 Be n n p 4 He

?

p

7

Be

 6

Be

 4

He

 2

p

6 Ве

Q

4

He

 2

p



M

4

He

 2

p



m

4

He

 2

m p

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Summary

The presented observations serve as an illustration of prospects of the Nuclotron and NTE for nuclear physics researches.

Due to a record space resolution the emulsion technique provides unique entirety in studying of light nuclei, especially, neutron-deficient ones. Providing the 3D observation of narrow dissociation vertices this classical technique gives novel possibilities of moving toward more and more complicated nuclear systems.

The results of an exclusive study of the interactions of relativistic 7,9 Be, 10,12 C nuclei lead to the conclusion that the known features of their structure are clearly manifested in very peripheral dissociations

.

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Thursday, 12 th September, Poster session.

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