-

Abstract

One-channel optical model (OM) approach is widely used for studying the scattering of light heavy-ions. The main problem in this model is to determine the shape of the OM potential that must produce successful results for explaining the observables of a specific reaction. In this study, the effects of shallow additional potentials, that added to the nuclear potential for describing the 16O+16O elastic scattering at the incident energies ELAB=75.0, 80.6 and 87.2MeV, have been investigated with respect to the experimental data. The most suitable phenomenological potential shape is searched by adding shallow additional potentials to the real or imaginary parts of a nuclear potential having WS2+iWS2 form that used in our OM calculations previously. The agreement between the results of the analyses and the experimental data is evaluated by the χ2 criterion. In general, the analyses using additional potentials in the imaginary part have revealed better results than the additional potentials with the real part. Furthermore, it is found that an additional potential of Woods-Saxon Derivative (WSD) shape used in the imaginary part with a potential depth of 30% reproduces the elastic angular distributions more successfully than the analyses with other shallow additional potential forms

Keywords

• 16O+16O elastic scattering, optical model, cross-section, additional potential

16O+16O Esnek Saçılmasının 5 MeV/n Civarında Sığ Ek-Potansiyeller Kullanılarak Tek-Kanal Optik Model Analizleri

Abstract

Özet: Tek-kanal optik model (OM) yaklaşımı, hafif ağır iyon saçılmalarının çalışılmasında yaygın biçimde kullanılmaktadır. Bu modeldeki temel problem, spesifik bir reaksiyonun gözlenirlerini açıklamak için başarılı sonuçlar üretebilecek bir OM potansiyel formunun belirlenmesi işlemidir. Bu çalışmada, ELAB= 75,0, 80,6 ve 87,2 MeV gelme enerjilerinde 16O+16O esnek saçılmasını açıklamak için kullanılan nükleer potansiyele eklenen sığ yapıdaki ek-potansiyellerin diferansiyel tesir-kesiti analizleri üzerindeki etkisi, deneysel veriler baz alınarak incelenmektedir. Önceki OM hesaplamalarımızda kullanılan WS2+iWS2 yapısındaki nükleer potansiyelin gerçel veya sanal kısımlarına sığ ek-potansiyeller eklenerek en uygun fenomenolojik potansiyel yapısı araştırılmıştır. Elde edilen analiz sonuçları ile deneysel veriler arasındaki uyum, χ2 hata hesabı ile değerlendirilmiştir. Genel olarak, sanal kısma eklenen ek-potansiyeller ile yapılan analizlerin gerçel kısma eklenen ek-potansiyellere göre daha iyi sonuçlar verdiği görülmüştür. Ayrıca, sanal kısma eklenen ve potansiyel derinliği %30 seçilen Wood-Saxon Derivatif (WSD) formundaki ek-potansiyelli analizlerin, diğer sığ ek-potansiyel formlarını içeren analizlere göre esnek açısal dağılım verilerini daha başarılı şekilde ürettiği bulunmuştur. Anahtar kelimeler: 16O+16O esnek saçılması, optik model, tesir-kesiti, ek-potansiyel One-Channel Optical Model Analyses of 16O+16O Elastic Scattering around 5 MeV/n by using Additional Shallow Potentials Abstract: One-channel optical model (OM) approach is widely used for studying the scattering of light heavy-ions. The main problem in this model is to determine the shape of the OM potential that must produce successful results for explaining the observables of a specific reaction. In this study, the effects of shallow additional potentials, that added to the nuclear potential for describing the 16O+16O elastic scattering at the incident energies ELAB=75.0, 80.6 and 87.2MeV, have been investigated with respect to the experimental data. The most suitable phenomenological potential shape is searched by adding shallow additional potentials to the real or imaginary parts of a nuclear potential having WS2+iWS2 form that used in our OM calculations previously. The agreement between the results of the analyses and the experimental data is evaluated by the χ2 criterion. In general, the analyses using additional potentials in the imaginary part have revealed better results than the additional potentials with the real part. Furthermore, it is found that an additional potential of Woods-Saxon Derivative (WSD) shape used in the imaginary part with a potential depth of 30% reproduces the elastic angular distributions more successfully than the analyses with other shallow additional potential forms. Key words: 16O+16O elastic scattering, optical model, cross-section, additional potential

Keywords

• 16O+16O esnek saçılması, optik model, tesir-kesiti, ek-potansiyel

References

1. Satchler G.R., 1980. Introduction to nuclear reactions, Mc Millan Press Ltd, London, pp.153-210.
2. Brandan M.E., Satchler G.R., 1997. The interaction between light heavy-ions and what it tells us, Physics Reports, 285 (4-5): 143-243.
3. Maher J.V., Sachs R.H., Siemssen R.H., Weildinger A., Bromley D.A., 1969. Nuclear interaction of oxygen with oxygen, Physical Review, 188 (4): 1665-1682.
4. Sugiyama Y., Tomita Y., Ikeoze H., Yamamuchi Y., Idenio K., Hamada S., Sugimutsu T., Hijiya M., Kondo Y., 1993. Observation of airy oscillation for the 16O+16O system at Elab=145MeV, Physics Letters B, 312 (1-2): 35-39.
5. Bartnitzky G., Blazenik A., Bohlen H.G., 1996. Model-unrestricted nucleus-nucleus scattering potentials from measurement and analysis of 16O+16O scattering, Physics Letters B, 365 (1-4): 23-28.
6. Kondo Y., Sugiyama Y., Tomita Y., Yamamuchi Y., Ikeoze H., Idenio K., Hamada S., Sugimutsu T., Hijiya M., Fujita H., 1996. Airy minimum crossing cm=90 at Elab=124MeV for the 16O+16O system, Physics Letters B, 365 (1-4): 17-22.
7. Nicoli M.P., Freeman F., Aissaou R.M., Beck N., Elanigue E., Noucier A., Morsad R., Szilner A., Basrak S., Brandan M.E., 1999. Refractive effects in the elastic scattering of light heavy ions between 5 and 10MeV/n: the 16O+16O reaction, Nuclear Physics A, 654 (1): 882-887.
8. Khoa D.T., von Ortezen W., Bohlen H.G., Nuoffer F., 2000. Study of diffractive and refractive structure in the elastic 16O+16O scattering at incident energies ranging from 124 to 1120MeV, Nuclear Physics A, 672 (1-4): 387-416.

9. Kondo Y., Robson B.A., Smith R., 1989. A deep potential description of the 16O+16O system, Physics Letters B, 227 (3-4): 310-314.
10. Brandan M.E., Satchler G.R., 1991. Optical potential ambiguities and 16O+16O at 350MeV, Physics Letters B, 256 (3-4): 311-315.
11. Gonzalez M.M., Brandan M.E., 2001. The dispersion relation applied to the radial shape and energy dependence of the 16O-16O potential at intermediate energies, Nuclear Physics A, 693 (3-4): 603- 615.
12. Khoa D.T., Bohlen H.G., von Ortezen W., Bartnitzky G., Blazevic A., Nuoffer F., Gebauer B., Mitting W, Roussel-Chomaz P., 2005. Study of reactive structure in the inelastic 16O+16O scattering at the incident energies of 250 to 1120 MeV, Nuclear Physics A, 759 (1-2), 3-22.
13. Cooper S.G., Mackintosh R.S., 1994. 16O+16O elastic scattering at 350 MeV studied by inversion, Nuclear Physics A, 576 (2): 308-316.
14. Kürkçüoğlu M.E., Aytekin H., Boztosun İ., 2006. Optical model analysis of the 16O+16O nuclear scattering reaction around Elab=5 MeV/nucleon, Gazi Üniversitesi Journal of Science, (19): 105- 112.
15. Kürkçüoğlu M.E., Aytekin H., Boztosun I., 2006. An investigation of the 16O+16O elastic scattering by using alpha-alpha double folding potential in optical model formalism, Modern Physics Letters A, 21 (29): 2217-2232.
16. Kürkçüoğlu M.E., Cof G., Aytekin H., Boztosun İ., 2013. Introducing a global optical model approach for analysing 16O+16O elastic scattering at 5-10 MeV/nucleon region, Süleyman Demirel Üniversitesi Fen Dergisi, (8): 71-81.
17. Feshbach H., Porter, C. E., Weisskopf, V. F. 1954. Model for nuclear reactions with neutrons, Physical Review, (96): 448–464.
18. Woods R. D., Saxon D.S. 1954. Diffuse surface optical model for nucleon-nuclei scattering, Physical Review, (95): 577–578.
19. Thompson, I.J., 1997. A Coupled-Channels Code (unpublished), FRESCO, England.
20. Merve TÜLÜLER e-posta: [e-mail]