FRAGMENTATION OF RELATIVISTIC 10 C NUCLEI IN NUCLEI EMULSION K. MAMATKULOV JINR, Dubna September

10 C 4 He p p 8 Be p p Energy levels of 10 C An example micrograph of nuclear fragmentation on event 10 C → 2He + 2H.

Irradiation of emulsion with beam nuclei 7 Be, 10 C and 12 N. Determination of charge of beam particles in the emulsion The mean-free path λ(А) for inelastic interactions depending on the mass of the projectile nuclei А; the curve - calculation by the value of Bradta Peters. Distribution of the secondary beam nuclei tracks (solid line) and fragments (dashed line) by the number of δ-electrons.  Viewed plates – 12 pcs.  The total length at viewing of primary tracks – m.  Number of total events – 7241  Number of events ("white stars“) – 608 λ exp.( 10 C) = 14.8 ± 0.9 cm λ calc. ( 10 C) = 14.7 cm

The observed fragmentation channels of 10 C nuclei ("White stars") Table 1. Channels ( 10 С)N ws =227100%N tf =627100% 2He+2H He+4H He ( 2 3 Не + 4 Не ) H Be + He B+H Li+3H С+n

Distribution of the fragments of the polar of emission angle formed in the "white stars" 10 C → 2He + 2H. (dotted line - isotopes H, solid line - He fragments) Rayleigh distribution for H and Не   (Н) = (51 ± 3) × rad   (Не) = (17 ± 1) × rad by the statistical model   ( 1 Н) ≈ 47× rad   ( 4 Не) ≈ 19 × rad

Identification of the isotopic composition of the fragments H and He Fig.(а). Distribution of the fragments by value pβc of the "white" stars 10 C  2He + 2H (solid line – He; shaded histogram – H) and 9 C  3 3 He (dotted line) Fig.(b). Distribution of the fragments by value pβc of the "white" stars, identified as 10 C  2 3 Не + 4 Нe (solid line) and 10 C  7 Bе + 3 He (shaded histogram) a)a) b)b)

9 Be  2  10 С  2α+2p Distributions of the “white” stars 10 С  2α+2p over energy Q 2α of pairs 2 

Distributions of the “white” stars 10 С  2α+2p over energy Q 2α+p of triples 2  + p 10 С  2α+2p provided that He= 4 He, H= 1 H 10 С → 9 В+р → 8 Ве+2р → 2α+2р

Rayleigh distribution  Pt ( 9 В) = (92  15) МeV/c by the statistical model  Pt ( 9 В) =93 MeV/c 10 С → 9 В + р → 8 Ве + 2р → 2α + 2р

Conclusions  The report presents the results of research fragmentation of nuclei 10 C with energy of 1.2 A GeV, the first derived at the Nuclotron, JINR.  Search and charge measurements of "white" stars are executed in 12 layers. On the total length of viewing of primary traces of m was found 7241 inelastic interactions, including 608 "white" stars. The mean free path of nuclei 10 C was equal to λ C = 14.8 ± 0.9 sm.  Conducted identification on the isotopic composition of the produced fragments H and He by value p  c for events 2He + 2H. In the gathered statistics of "white" stars 2He + 2H all He nuclei correspond to isotope 4 He (α), and H - 1 H (p).  Distribution of charge topology indicates the lead role of the channel with a charge configuration 10 C → 2α + 2p (82%)  The process of fragmentation of nuclei 10 C → 2α +2 p in case (≈ 30%) have a cascade character 10 C → 9 B → 8 Be by analogy with the nucleus 9 Be.  Further analysis of the angular distributions 2α + 2p will be directed to the events without formation of nuclei 8 Be g.s and 9 B. In particular, will be performed search the decays of nuclear resonances 5 Li and 6 Be.

Thank you for attention!