The BECQUEREL Project Progress Report for Years 2006

The BECQUEREL Project: Progress Report for Years 2006 -8 and Plans for 2009 -11 D. A. Artemenkov, V. Bradnov, A. I. Malakhov, D. O. Krivenkov, P. A. Rukoyatkin, V. V. Rusakova, T. V. Shchedrina, P. I. Zarubin, I. G Zarubina V. I. Veksler and A. M. Baldin Laboratory of High Energy Phyiscs, JINR, Dubna, Russia M. M. Chernyavsky, S. P. Kharlamov, S. G. Gerasimov, L. A. Goncharova, G. I. Orlova, N. G. Peresadko, N. G. Polukhina P. N. Lebedev Physical Institute RAS, Moscow, Russia М. Haiduc, A. Neagu, E. Stefan Institute of Space Sciences, Bucharest-Magurele, Romania A. A. Moiseenko, V. R. Sarkisyan Erevan Physical Institute, Erevan, Armenia R. Stanoeva Institute for Nuclear Research and Nuclear Energy BAS, Sofia, Bulgaria S. Vokal Safarik University, Kosice, Slovakia

Nuclear beams of energy higher than 1 A Ge. V are recognized as a novel opportunity for the nuclear structure explorations. Among all variety of the nuclear interactions the peripheral dissociation bears uniquely complete information about the excited nucleus states above particle decay thresholds. The BECQUEREL Project (Beryllium (Boron) Clustering Quest in Relativistic Multifragmentation) at the JINR Nuclotron is devoted systematic exploration of clustering features of light stable and radioactive nuclei. A nuclear track emulsion is used to explore the fragmentation of the relativistic nuclei down to the most peripheral interactions - nuclear "white" stars. This technique provides a record spatial resolution and allows one to observe the 3 D images of peripheral collisions. The analysis of the relativistic fragmentation of neutron-deficient isotopes has special advantages owing to a larger fraction of observable nucleons.

Nuclear Track Emulsions Superposition of microphotographs of interaction of relativistic nucleus 32 S and human hair taken with MBI-9 microscope and NIKON camera

NUCLOTRON: 2. 1 А Ge. V 132 events 1. 2 A Ge. V 14 N → 3 He + H 50 “white” stars (2 events 6 He+3 He+4 He+1 H) Tatjana Shchedrina

Physics Program Nuclear Clustering

CO 2 laser

Zpr/Apr = 4/9 10 B → 9 Be

370 events 1. 2 A Ge. V 9 Be→ 2 He +1. 7 Me. V 144 “white” stars 27 stars with target proton recoil (g-particle) 39 stars with heavy fragment of target nucleus (b-particle) Denis Artemenkov

0+, 8 Be(92 Ke. V, 6. 8 e. V) 2+, 8 Be(2. 9 Me. V, 1. 5 Me. V)

Suggested analysis: 2000 events 9 Be + p → 2α Nadezhda Kornegrutsa

Zpr/Apr = 4/7 7 Li → 7 Be

Me. V 1. 6 6. 9 25. 3 21. 2 5. 6

Zpr/Apr = 5/8 10 B → 8 B

Diagram of peripheral dissociation of relativistic 8 B nucleus in EM field of Ag nucleus Nearer approach of the nuclei with an impact parameter (a), absorption of quasireal photon by 8 B nucleus (b), 8 B dissociation on fragment pair - p and 7 Be (c).

8 В (1. 2 A Ge. V) → Ralica Stanoeva 7 Ве +p

8 B → 3 He 2 + 2 H

Zpr/Apr = 2/3 12 C → 9 C

Major task: 9 С exposure analysis of Dmitry Krivenkov

Zpr/Apr = 5/12 12 C → 12 N

Suggested 10 C exposure

10 С

1. 0 A Гэ. В 10 B→ 23 Не+4 Не

Suggested 11 C exposure

2. 0 A Ge. V 11 B→ 4 Не+7 Be

CONCLUDING REMARKS The presented observations serve as an illustration of prospects of the Nuclotron for nuclear physics and astrophysics researches. In spite of an extraordinarily large distinction from the nuclear excitation energy the relativistic scale does not impede investigations of nuclear interactions down to energy scale typical for nuclear astrophysics, but on the contrary gives advantages. The major one of them is the possibility of principle of observing and investigating multi-particle systems. The investigations with light nuclei provide a basis for challenging studies of increasingly complicated systems He – H - n produced via multifragmentation of heavier relativistic nuclei in the energy scale relevant for nuclear astrophysics. In this respect, the motivated prospects are associated with a detailed analysis of the already observed fragment jets in the events of EM&Diffractive dissociation of Au nuclei at 10. 6 A Ge. V and Pb nuclei at 160 A Ge. V. Due to a record space resolution the emulsion technique provides unique entirety in studying of light nuclei, especially, neutron-deficient ones. Providing the 3 D observation of narrow dissociation vertices this classical technique gives novel possibilities of moving toward more and more complicated nuclear systems. Therefore this technique deserves upgrade, without changes in its detection basics, with the aim to speed up the microscope scanning for rather rare events of peripheral dissociation.

28 3. 65 A Ge. V Si 2+2+2+1

NUCLOTRON: 1 A Ge. V Elena Stefan Alina-Tania Neagu 56 Fe

SPS: 158 A Ge. V/c Pb 1 2 4 5 3 6

Наименование узлов и систем установки, ресурсов, источников финансирования Основные узлы и оборудование 1. Датчики для микроскопов 2. Электроника, ФЭУ Предложения лабораторий по распределению финансирования и ресурсов 2 г. 35 тыс. долл. 20 тыс. долл. 100 1. 20 тыс. дол. 2. 60 тыс. долл. 1 г. 100 35 тыс. долл. 20 тыс. долл. ОП ОИЯИ – нормо Необходимые ресурсы час механические работы – электроника КБ ЛАБОРАТОРИЯ ООЭП Стоимость узлов (тыс. долл. ) установки. Потребности в ресурсах 1 чел. год Ускоритель (Нуклотрон) Реактор ЭВМ (тип) 1 чел. год Эксплуатационные расходы бюджет Затраты из бюджета, в том числе инвалюные средства внебюджетные Вклады коллаборантов Средства по грантам Вклады спонсоров Средства по договорам Другие источники и т. д. Источники финансирования 80 тыс. долл. 4 г. 5 г.

Запрос на приобретение электронной аппаратуры формирования пучков на 2009 -11 гг. 1. Фотоумножители (Hamamatsu, Photonis) 700 Euro 7 шт. 5000 Euro 2. Зарядово-цифровой преобразователь CAEN C 1205 или аналогичный 4000 Euro 1 шт. 4000 Euro 3. Материалы и радиоэлектронные комплектующие детекторов и приемной электроники 2500 Euro 4. Осциллограф TDS 3000 B 8000 Euro 3000 Euro 1 шт. 8000 Euro Итого: 20000 Euro (7000 Euro в год)

8 В (1. 2 A Ge. V) → 2 Не + Н

Measured Charges of Secondary Fragments of 8 В Nucei Density of δ-electrons per 1 мм length of beam particles Zfr > 2.

8 B: Total PT (7 Be+p) EMD “white”stars n h≠ 0