176,178,180Hf İZOTOPLARINDA FOTON SAÇILMA TESİR KESİTLERİNİN HESAPLANMASI

Yıl 2013, Cilt: 1 Sayı: 2, 175 - 184, 01.12.2013

Hüseynqulu Quliyev , Ekber Gulıyev

Öz

Spini ve paritesi Iπ =1+ olan çekirdek seviyelerinin gözlenmesinde foton saçılma tesir kesitlerinin önemli yeri vardır. Bu seviyeleri karakterize eden Γγ radyasyon kalınlıkları ve B(M1) değerleri deneylerde gözlenen tesir kesitlerinden hesaplanmaktadır. Bu çalışmada makas mod uyarılmalarının esnek olamayan γ-çekirdek saçılma tesir kesitleri 176,178,180Hf izotopları için, teorik olarak dönme değişmez Kuazi-parçacık Rastgele Faz Yaklaşımı (QRPA) kullanılarak araştırılmıştır. Bu seviyelerin (K=1) foton saçılma reaksiyonlarında gözlenen σγγ›, B(M1) ve Γγ radyasyon kalınlıkları teorik sonuçlarla karşılaştırılarak incelenmiştir. Genel olarak teorik ve deney sonuçlarının, ölçüm hataları çerçevesinde, uyum içinde olduğu görülmüştür. Hesaplamalar Hf izotoplarında manyetik dipol 1+1 seviyelerin, iyi deforme çekirdeklere nazaran daha az ayrışmakta olduğunu göstermiştir. Teori düşük enerjilerde birkaç tane E1-elektrik dipol uyarılmalarının varlığını da öngörmektedir. Teorik ve deney sonuçlarının karşılaştırılması gözlenen seviyelerin paritelerinin belirlenmesinde deneycilere ipucu sağlayacaktır.

Anahtar Kelimeler

176, 178, 180Hf, Saçılma Tesir Kesiti, QRPA, Manyetik Dipol

176,178,180Hf İZOTOPLARINDA FOTON SAÇILMA TESİR KESİTLERİNİN HESAPLANMASI

Öz

In the observation of Iπ = 1+ levels ın nuclei photon scattering cross sections have an important place. Γγ radiation thickness and B (M1) values which characterize this level are calculated from the cross sections observed in the experiments. In this study non flexible γ-nuclei scattering cross sections of the scissors mode excitations for 176,178,180Hf isotopes were theoretically investigated using the rotation invariant Quasiparticle Random Phase Approximation (QRPA). σγγ’, B(M1) ve Γγ radiation thickness observed in the photon scattering reaction of these levels (K=1) is compared with the theoretical results. In general, the theoretical and experimental results in accordance with the measurement error, is seen to be ingood agrement. The calculations of the magnetic dipole 1+1 levels in Hf isotopes showed that the decompsitation in this isotope chain is less that observed in well deformed nuclei decomposed. Theory predicted the presence of a few E1-electric dipole excitations at low energies. The comparison of the theoretical and the experimental results will provide clues to the experimenters in the determination of the parity of the observed levels

Anahtar Kelimeler

176, 178, 180Hf, scattering cross section, QRPA, magnetic dipol

Kaynakça

• Davıdov A.S. “Theory of atomic nuclei’’ Atomizdat, Moscow, 1961.
• Metzger, F.R. Resonance fluorescence in nuclei. Prog. Part. Nucl.Phys.7;54-88; Metzger,
• Beil, H and Berdere, R. Monochromatic and identifiable photons used in photonuclear
• research. Note CEA-N2144, 1-130, 1980.
• Skorka, S.J. Nuclear resonance fluorescence In Nuclear Spectroscopy North Holland Publ.Company, Amsterdam; 283- 310, 1975.
• Moreh, R. Review of intense gamma sources using neutron capture. Nucl.Instr. and Meth.166;29-38 ; Studies in nuclear spectroscopy using the (γ,γ’) and the (γ,n) reactions. Nucl.Instr. and Meth. 166;69-84, 1979.
• Moreh, R. Low energy photon scattering. Intermediate Energy Nuclear Physics. World Scientific Pub.Co., Singapore; 1-63, 1982.
• Kneissl, U., Pitz, H.H., Zilges, A. Investigation of nuclear structure by resonance fluorescence scattering. Prog. Part. Nucl. Phys. 37, 349-433, 1996.
• Pitz, H.H., Berg, U.E.P., Heil, R.D., Kneissl, U., Stock, R., Wesselborg, C. , Brentano, P.
• von, Systematic study of low-lying dipole excitations in 156,158,160Gd by photon scattering.
• Nucl.Phys. A492, 411-425, 1989.
• Berg, U.E.P., Blasing, C., Drexler, J., Heil, R.D., Kneissel,U., Naatz,W., Ratzek, R.,Schennach, S., Stock, R., Weber, T., Wickert, H., Fıscher, B., Hollick, H., and Kollewe, D. Photoexcitation of low-lying collective states in 156,158,160Gd. Phys.Lett. B149, 59-63, 1984.
• Baldwin, G.C. and Klaiber, G.C. Photo- Fission in Heavy Elements. Phys. Rev.
• 71(1), 3-10, 1947.
• Goldhaber, M. and Teller, E. On nuclear dipole vibrations. Phys. Rev. 74(9), 1046- 1049, 1948.
• Bohr, A., Mottelson, B. Nuclear Structure, W.A. Benjamin, v.1, NewYork, 1969; v.2,-
• NewYork, 1975.
• Guliyev E. Doktora Tezi “SEL γ-çekirdek çarpıştırıcıları ile Nükleer spectroskopi ve kolektıf çekirdek uyarılmaları’’ Ankara Üniversitesi Fen Bilimleri Enstitüsü 2002.
• Richter, A. Trends in nuclear physcics. Nucl. Phys. A553, 417c-462c, 1993.
• Maidment, J.R. Ion acceleration at HERA. Ion99 Workshop, Desy, Germany, 1999.
• Aktaş, H., Büget, N., Çiftçi, A.K., Meriç, N., Sultansoy, S., Yavaş, Ö. New tool for “old” nuclear physics: FELγ-nucleus colliders. Nucl. Instr. and Meth. A 428, 271- 275, 1999.
• Gabrakov, S.I., Kuliev, A.A., Pyatov, N.I. States I π =1+ in even-even deformed nuclei.
• Sov. Journ. of Nucl. Phys. 12, 82-90, 1970.
• Gabrakov, S.I., Kuliev, A.A. , Pyatov N.I. Salamov, D.I.,Schuiz, H.Collective 1+-states
• in double even deformed nuclei. 1972. Nucl. Phys. A 182, 625-633, 1972.
• Soloviev, V.G. Theory of Complex Nuclei. Pergamon Press New York, 1976.
• Kuliev, A.A., Akkaya,R., Ilhan,M., Guliyev, E.,Salamov, C., Selvi S. Rotational
• invariant model of the states with Kπ=1+and their contribution to the scissors mode.
• Int.J. of Mod. Phys. E9, 249-261, 2000.
• E. Guliyev, F. Ertuğral, A.A. Kuliev “Low-lying magnetic dipole strength distribution
• in the γ -soft even-even 130-136Ba’’ Eur. Phys. J. A 27, 313, 2006.
• Gouliev, A. and Yavaş, Ö. A search for the collective Iπ=1+ excitations in 140Ce
• nucleus at FELγ-nucleus collider. Bulg. J. Phys. 27, 21-24, 2000.
• E.Guliyev, A.A.Kuliev, F.Ertugral. Systematic investigation of the low-energy dipole excitations in176,178,180Hf within rotational, translational and Galilean invariant
• quasiparticle RPA, Nucl. Phys.s A 915,78– 89, 2013.
• Dwight H.B. “Table of Integrals and other mathematical data” Edition, 4. Publisher, Macmillan, 1961.
• Dudek, J., Nazarewıcz, W., Faessler, A., Theoretical analysis of the single-particle states in the secondary minima of fissioning nuclei, Nucl. Phys. A, 412, 61-91, 1984.
• Bohr, O. and Mottelson, B. Nuclear Structure Vol 2 ed. Benjamin, New York Amsterdam,
• 1975.
• Raman, S., Nestor, C.W. and Tikkanen, P. At. Data Nucl. Data Tables 78, 1, 2001.
• Sheck, M., Belic, D., von Brentano, P., Carrol, J.J., Fransen, C., Gade, A., von Garrel, H., Kneissl, U., Kohstall, C., Linnemann, A., Pitz, H.H., Stedile, F., Toman, R. and Werner, V. Photon scattering experiments off 176Hf and systematics of low-lying dipole modes in stable even-even Hf isotopes 176,178,180Hf, Physical Review C 67, 064313, 2003.
• Pietrella, N., Beck, O., Besserer, J., Von Brentano, P., Eckert, T., Fischer R. et. al. The scissors mode other magnetic and electric dipole excitations in the transitinonal nuclei 178,180Hf, Nuclear Physics A 618, 1997.