DeltaSigma experiment First measurement of the cross section

Delta-Sigma experiment First measurement of the cross section ratio in charge-exchange (np) reactions on H 2/D 2 at 0° and T = 1, 1. 2 Ge. V Dubna, Joint Institute for Nuclear Research Veksler and Baldin Laboratory of High Energies Morozov A. A.

Participants of the Dubna "DELTA-SIGMA" Experiment S. A. Averichev, L. S. Azhgirey, N. G. Anischenko, V. D. Bartenev, N. A. Blinov, N. S. Borisov, S. B. Borzakov, Yu. T. Borzunov, Yu. P. Bushuev, L. P. Chernenko, E. V. Chernykh, V. F. Chumakov, L. B. Golovanov, A. Janata, S. A. Dolgii, A. N. Fedorov, V. V. Fimushkin, M. Finger Jr, A. D. Kirillov, A. D. Kovalenko, V. G. Kolomiets, N. I. Kochelev, V. A. Krasnov, P. Krstonosich, E. S. Kuzmin, N. A. Kuzmin, V. P. Ladygin, A. B. Lazarev, A. N. Livanov, P. K. Maniakov, V. N. Matafonov, E. A. Matyushevsky, A. A. Morozov, A. B. Neganov, G. P. Nikolaevsky, A. A. Nomofilov, Tz. Panteleev, Yu. K. Pilipenko, I. L. Pisarev, Yu. A. Plis, V. Yu. Prytkov, P. A. Rukoyatkin, A. L. Svetov, M. Slunechka, V. Slunechkova, A. Yu. Starikov, L. N. Strunov, V. I. Sharov, S. N. Shilov, R. A. Shindin, Yu. A. Usov, T. A. Vasiliev, V. I. Volkov, E. I. Vorobiev, I. P. Yudin, V. N. Zhmyrov, I. V. Zaitsev. Joint Institute for Nuclear Research, Dubna V. G. Baryshevsky, K. G. Batrakov, T. I. Klimkovich, S. L. Cherkas RNNP, Belorussian State University, Belorussia N. A. Bazhanov, A. A. Zhdanov, A. I. Kovalev, A. N. Prokofiev, V. A. Schedrov Peterburg Institute of Nuclear Physics, Gatchina G. M. Gurevich Institute for Nuclear Research, RAS, Moscow V. G. Antonenko, Yu. P. Polunin Russian Scientific Center "Kurchatov Institute", Moscow G. Durand, F. Lehar. A. de Lesquen DAPNIA, Saclay, France A. P. Dzyubak, A. A. Lukhanin Kharkov Institute of Physics and Technology, Kharkov, Ukraine

The Delta-Sigma Experiment Research Program

The Delta-Sigma Experiment Research Program

Delta-Sigma spectrometer q Magnet SP 94 q Liquid H 2/D 2 Target q Neutron monitors (M 1, 2) Multiwire proportional chambers (Gx, Gy, 1 x, 2 x, 3 y, 4 x, 4 y) placed in front of and behind the magnet q Veto-counter (A), trigger scintillation counters (S 1, ST 1, 2, 3), q q. Time-of-Flight (TOF 1, 2) system

Delta-Sigma spectrometer q Magnet SP 94 q Liquid H 2/D 2 Target Multiwire proportional chambers (Gx, Gy, 1 x, 2 x, 3 y, 4 x, 4 y) placed in front of and behind the magnet q Veto-counter (A), trigger scintillation counters (S 1, ST 1, 2, 3), q

System for Target Surrounding

The momentum spectra of deuteron beam, used for calibration of the spectrometer

The momentum spectra of charged particles , detected by spectrometer using H 2 and D 2 liquid targets, at the neutron beam energy of 1. 0 Ge. V. The main contribution in background (inelastic) peak is due to the binary reaction with excitation of Δ°-resonance.

The momentum spectra of charged particles , detected by spectrometer using H 2 and D 2 liquid targets, at the neutron beam energy of 1. 2 Ge. V. The main contribution in background (inelastic) peak is due to the binary reaction with excitation of Δ°-resonance.

Time-of-Flight System

Time-of-Flight System

Time-of-Flight System

Detected Events Distribution in the θ vs φ Plane

Differential cross section and ratio Rdp calculation

Angular dependence of differential cross section of the np→pn process near 0°, obtained with H 2 and D 2 targets at Tn = 1. 0 Ge. V.

Angular dependence of differential cross section of the np→pn process near 0°, obtained with H 2 and D 2 targets at Tn = 1. 0 Ge. V.

The ratio Rdp at neutron energy Tn =1 Ge. V. The ratio Rdp(0) was obtained by the extrapolation of the direct line approximating of experimental Rdp(θ) data (with χ2≈ 0. 5) Rdp(0)=0. 52 ± 0. 02

The ratio Rdp at neutron energy Tn =1. 2 Ge. V. The ratio Rdp(0) was obtained by the extrapolation of the direct line approximating of experimental Rdp(θ) data (with χ2≈ 0. 5) Rdp(0)=0. 5 ± 0. 02

Results Our preliminary results on the momentum spectra of elastic charge exchange protons with H 2 target and corresponding dσ/dΩ(np) at 1. 0 and 1. 2 Ge. V are in agreement with the existing data: [1] G. Bizard, F. Bonthonneau, J. L. Laville et al. : Nucl. Phys. B 85 (1975) 14. [2] G. Bizard, F. Bonthonneau, J. L. Laville et al. : Nucl. Phys. B 108 (1976) 189. p

Results p Preliminary results of measurements of the ratio Rdp=dσ/dΩ(np) / dσ/dΩ(nd) at 0° were obtained at the first time at Tn ≥ 1 Ge. V. Rdp(0)=0. 52± 0. 02 (Tn = 1 Ge. V) Rdp(0)=0. 50± 0. 02 (Tn = 1. 2 Ge. V)

Results

Conclusion A number of physical and methodical results on investigation of the elastic np→pn charge-exchange process over a few Ge. V region are presented. The possibilities for A 00 kk(np), A 00 nn(np) and Rdp measurements, using prepared magnetic spectrometer, were demonstrated. ----------------------------------------------------We are grateful to the JINR, JINR VBLHE and DLNP Directorates for these investigations support. The investigations were supported in part by the Russian Foundation for Basic Research (Grant № 02– 17129).