Reaction with light nuclei

Nuclear reactions group: Cracow – Kiev – Warsaw

Andrzej Sołtan Institute of Nuclear Studies, ul. Hoża 69, 00-681 Warsaw, Poland
K.Rusek, S. Yu. Mezhevych

Institute of Nuclear Research, Prospect Nauki 47, 03680 Kiev, Ukraine
A.T.Rudchik, V.M. Kyryanchuk, A.V. Mokhnach, O.A. Momotyuk, Val.M. Pirnak, O. Ponkratenko, V. Romanyshyn, A.A. Rudchik

H.Niewodniczański Institute of Nuclear Physics, ul. Radzikowskiego 152, 31-342 Cracow, Poland
A. Budzanowski, B.Czech, S.Kliczewski, R. Siudak, I.Skwirczyńska

Kharkiv State University, 61077 Kharkiv, Ukraine
E.Koshchy

Heavy Ion Laboratory of Warsaw University, ul. Pasteura 5A, 02-093 Warsaw, Poland
T. Czosnyka, J. Choiński, A. Stolarz

Military University of Technology, ul. Kaliskiego 2, 00-908 Warsaw, Poland
L.Głowacka

Contact: Krzysztof Rusek, Krzysztof.Rusek(at)fuw.edu.pl

Nuclear reactions are the main source of experimental information on the structure of nuclei, mechanisms of nuclear processes and properties of nucleus-nucleus interaction. This information, for instance, may be obtained from the theoretical analysis of angular distributions of the measured reaction products. The present theoretical models used for such an analysis are parameterized, and the parameters describing nuclear structure, mechanisms of reactions and nucleus-nucleus interactions are closely related to each other. Therefore, for the reliable determination of these parameters a broad set of experimental data is demanded for reactions with different nuclei in the entrance and exit channels and at different energies. Thus, obtaining new experimental data remains an urgent task in nuclear physics.

We perform experiments with the ¹⁰B³⁺, ¹¹B²⁺, ¹²C²⁺, ¹⁴N³⁺ and ¹⁸O⁴⁺ ion beams, accelerated at Warsaw Cyclotron U-200P up to an energy of 5-10 MeV/A, which are scattered from the ^6,7Li, ⁹Be, ^12,13,14C targets. The experimentally obtained angular distributions of the reaction products are analyzed by means of the coupled-reaction-channels method, and the parameters describing the structure of the nuclei, mechanisms of nuclear reactions and nucleus-nucleus interactions are deduced. We start with the investigation of the elastic and inelastic scattering in order to obtain a reliable set of optical model parameters describing the nucleus-nucleus interaction in the entrance channel, which are then employed in the calculations of different transfer processes leading to the production of the experimentally observed nuclei in the exit reaction channels.

EXPERIMENTAL SETUP “SYRENA” AT WARSAW CYCLOTRON

The setup is located in section “B” of the experimental hall of the Heavy Ion Laboratory of Warsaw University. The picture of the scattering chamber is shown in Fig.1. In the center of the chamber a frame with targets is fixed on a movable rod. The scattering chamber has two movable platforms on which the detectors are mounted. Three-channel ΔE-E spectrometer, with the gas-filled ionization chamber serving as the ΔE – detector, is mounted on the lower platform (see Fig.2). At the backward side of the ionization chamber silicon E-detectors (approx. 500 μm), stopping the reaction products, are mounted. Angular separation between the channels is 9.5^o. On the upper platform the second ΔE-E spectrometer consisted of the silicon ΔE (approx. 60 μm) and E (approx. 500 μm) detectors is placed.

Figure 1: Scattering chamber of the experimental setup “SYRENA”.

Figure 2: The scattering chamber in the inside.

In Fig.3 a typical two-dimensional energy spectrum of the ⁷Li(¹²C,X) reaction products at E_lab(¹²C) = 115 MeV registered at Θ_lab = 15^o by the silicon ΔE-E spectrometer is shown. Very good energy resolution of the detectors leads to a good separations between Li, Be, B, C and N isotopes.

Figure 3: ΔE-E spectrum of the ⁷Li(¹²C,X) reaction products.

RESULTS OBTAINED USING THE BEAM FROM THE WARSAW CYCLOTRON

So far we have published five papers (see the list below). They contain new experimental data sets as well as many interesting conclusions drawn from the data analyses. As an example we present in Fig. 4 the angular distribution of the inelastically scattered ¹¹B from ¹⁴C target leading to the excitation of the 7.012 MeV (2+) excited state of ¹⁴C. The curves present results of the coupled-channels calculations. Collective model of the target nucleus was assumed. The short dashed curve was obtained assuming the positive quadrupole deformation (β₂ = +0.2) of ¹⁴C, while the solid curve was obtained with the negative quadrupole deformation (β₂ = -0.2.).

Figure 4: The results of the calculations compared to the experimental data.

BIBLIOGRAPHY

(The experimental data obtained at Warsaw Cyclotron serves as the experimental material for four PhD theses as well as two DSc dissertations)

A.T.Rudchik, A.Budzanowski, V.K.Chernievsky, B.Czech, L.Glowacka, S.Kliczewski, A.V.Mokhnach, O.A.Momotyuk, S.E.Omelchuk, V.M.Pirnak, K.Rusek, R.Siudak, I.Skwirczynska, A.Szczurek, L.Zemlo,
The ¹¹B + ¹²C Elastic and Inelastic Scattering at E_lab(¹¹B) = 49 MeV and Energy Dependence of the ¹¹B + ¹²C Interaction,
Nucl.Phys. A695, 51 (2001)
S.Yu.Mezhevych, K.Rusek,
Quadrupole deformation of ¹¹B (3/2-, 5.02 MeV) excited states from ¹¹B + ¹²C scattering,
Acta Phys.Pol. B34, 2415 (2003)
A.T.Rudchik, V.M.Kyryanchuk, A.Budzanowski, V.K.Chernievsky, B.Czech, T.Czosnyka, A.V.Glowacka, S.Kliczewski, E.I.Koshchy, S.Yu.Mezhevych, A.V.Mokhnach, K.Rusek, S.B.Sakuta, R.Siudak, I.Skwirczynska, A.Szczurek, L.Zemlo,
Mechanism of large angle enhancement of the ⁹Be+¹¹B scattering,
Nucl.Phys. A714, 391 (2003)
S.Yu.Mezhevych, K.Rusek, A.T.Rudchik, A.Budzanowski, V.K.Chernievsky, B.Czech, J.Choinski, L.Glowacka, S.Kliczewski, E.I.Koshchy, V.M.Kyryanchuk, A.V.Mokhnach, A.A.Rudchik, S.B.Sakuta, R.Siudak, I.Skwirczynska, A.Szczurek, L.Zemlo,
The ¹³C + ¹¹B elastic and inelastic scattering and isotopic effects in the ^12,13C + ¹¹B scattering,
Nucl.Phys. A724, 29 (2003)
V.M.Kyryanchuk, A.T.Rudchik, A.Budzanowski, V.K.Chernievsky, T.Czosnyka, B.Czech, L.Glowacka, S.Kliczewski, E.I.Koshchy, S.Yu.Mezhevych, A.V.Mokhnach, K.Rusek, S.B.Sakuta, R.Siudak, I.Skwirczynska, A.Szczurek, L.Zemlo,
One-nucleon transfer reaction ⁹Be(¹¹B, ¹⁰B)10Be and optical potential for the ¹⁰B + ¹⁰Be interaction,
Nucl.Phys. A726, 231 (2003)
S.Yu.Mezhevych, K.Rusek, A.T.Rudchik, A.Budzanowski, B.Czech, J.Choinski, L.Glowacka, S.Kliczewski, E.I.Koshchy, V.M.Kyryanchuk, A.V.Mokhnach, A.A.Rudchik, S.B.Sakuta, R.Siudak, I.Skwirczynska, A.Szczurek,
Structure of ¹⁴C from ¹¹B + ¹⁴C scattering,
submitted to Nucl.Phys. A
A.A.Rudchik, A.T.Rudchik, A.Budzanowski, A.Szczurek, B.Czech, T.Czosnyka, J.Choinski, L.Glowacka, S.Kliczewski, E.I.Koshchy, S.Yu.Mezhevych, A.V.Mokhnach, O.A.Momotyuk, Val.M.Pirnak, R.Siudak, I.Skwirczynska,
Mechanism of ¹²C(¹¹B,¹⁵N)8Be reaction and ⁸Be + ¹⁵N optical model potential,
submitted to Eur. Phys. J. A