I OFL. - EK . . WO a :. . . :. ORNL P 2438 • meno. 2 1 . . . .. + • : . . . . * . - : . - .. . . - TFFSEER I pinia 1.25 1.1.4 16 1 -1 i . MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDARDS -1963 ; MA ORNL. -- 2438 Conf-660906-18 :-ORNL > AEC - OFFICIAL SEP 2 2 1966 Analysis of the Analogue state Resonaces in 208 pb (p.p.) 208 pb and 208 Pb (p.p') 208Pb* Processes* CESTI PRICES Taro Tamura Oak Ridge National Laboratory, Oak Ridge, Te LC $ 400, MN.SE ORNI - AES-OFFIC (abstract) .win- ... ... . Analysis was made of the data on the analogue state resonances in the 208 Pb (p.p.) 208pb and 208 Pb (p.p.) 208Pb* processes in terms of an extended coupled-channel calcu- . lation. Rather good agreement with experiment was obtained. The derived spectroscopic factor was also in accord.... with that obtained from a (d,p) analysis. : RELEASED FOR ANNOUNCEMENT ' IN NUCLEAR SCIENCE ABSTRACTS LEGAL NOTICE This report was prepared 38 an account of Goverament sponsored work. 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"Research sponsored by the U. S. Atomic Energy Commission under contract with the Union Carbide Corporation. ORNL – AEC - OFFICIAL ORNI - AEC - OFFICIAL i .. .. a ORNI - AEC - OFFICIAL ORNL - AEC - OFFICIAL a ANALYSIS OF THE ANALOGUE STATE RESOLIANCE IN 208Pb (p, p.) 208pb and 208Pb (p,p') 208P6 PROCESSES* . . . S by Taro Tamura, Oak Ridge National Laboratory, Oak Ridge, Tennesse It is known that isobaric analogue state resonances appear in (p,p') processes as well as in (p,p.) processes”). Analysis of the excitation functions in such resonances in (P,P.) processes have been made, either in terms of the R- matrix theory“) or of the coupled-channel calculations' (C.c.), and useful spectroscopic informations were derived from such analyses. The purpose of the present paper is to dicuss the extention of the C.C. procedure to a combined analysis of the (PP) and (p,p') resonances. The coupled equations that are to be solved for that purpose can be constructed in the following way. First we write down the coupled equations that describe the scatter- ing of a proton by a (core) nucleus c, chosen as a target. We assume that the proton has an energy E. We then write down exactly the same equation for a neutron to be bound to a nucleus A, which is the analogue of C; A = T_C. The energy ORNI - AEC - OFFICIAL "Research sponsored by the U. S. Atomic Energy Commission under contract with the Union Carbide Corporation. ORNE - AEC - OFFICIAL - 2 - ORNI PAEC - OFFICIAL of the neutron is given by E. = E. - A', where se is the Coulomb energy of a proton plus the neutron-proton mass ORNI - AEC - OFFICIAL difference. We are interested in the case in which 4 ESO and thus E (0. We then finall; introduce an interaction of the form (t.T)U, (r) which couples the proton part of the equations to the neutron part. If these equations are solved, the cross sections for the (P,P) and (p,p') processes are obtained. Let us assume that we succeed in fitting the experimental excitation functions of these prócesses in this way, and thus that e ... - be appropriate values of the parameters involved in these equa- .-*-:* - tions are fixed. The next task we should do is to solve the - . .-'- neutron part of the equations, after dropping the coupling to the proton part but keeping the above parameters as they are. Note that the derived equations are now all in the negative energy state, and what we shall obtain by solving these equations is one of their eigensolutions. Take as an example, the scattering of a proton with E ~ 15 MeV by 208Pb, and assume that the coupling of the of ground state channel to the 3™ state (at 2.615 MeV) channel is the only important coupling to be considered. We know that there occurs a JT - 24 analogue state resonance in the 208 Pb + p system for E. ~ 15 MeV. The eigensolution, that is obtained in the last step of the calculation explained above, is nothing ORNI – AEC - OFFICIAL ORNL - A'. - OFFICIAL JYK-234- INYO - 3 - hut the eigenfunction of the + ground states of 209pb, and at may be written as ORNI - AEC - OFFICIAL 15/2 at = ot you in t(43-84-) , j=3/2 where or means the.. wave function of a state in "*°pb, '4 that of a neutron and a vector coupling. et suves, Y . If yo of (1) is normalized to unity, then i Bot, t - 5 y. try Par (2) is nothing but the spectroscopic factor, which is to have the same meaning, and thus the same value with the spectro- scopic factor that will be obtained from the analysis of a 208 Pb (d,p) 209 Pb (**) reaction with the angular-momentum trans- the other hand the quantity 83-,;- - 5 43-(e)? dr (3) is the spectroscopic factor that is to be compared with the one obtained from a 208Pb(3-) * (d,p) 209 Pb (at) reaction (i.e.f' an experiment with a target in an excited state) with an angular- momentum transfer j. Obviously the latter type of experiment: sing ORNL - A'. - OFFICIAL ORNL - AEC - OFFICIAL - 4 - ORNL - AEC - OFFICIAL is unfeasible, but the quantity in (3) can certainly be obtained from our analysis. The result of the theoretical fitting to the experimental excitation functions, is shown in Fig. 1, and it is seen that the agreement is rather good. The spectroscopic factors obtained are Sot;2+ = 0.893, (4.1) 83,1 = 0.027, 83-, 4- 0.0002, 83-4 = 0.004, $3–= 0.001, 93-12 = 0.011, 93-1 = 0.009, (4.2) $3-= 0.055. Among the results given in (4) the value 50+,24 = 0.893 is in very good agreement with the value S = 0.90 as obtained in a recent preliminary analysis of a 40° Pb(d,p) reaction®). The reasonable fit to experiment obtained in Fig. 1, . and the good agreement of our spectroscopic factor to the (d,p) value seem to indicate that our approach is basically correct, and with further more extensive calculations would prove to be a powerful tool for the nuclear spectroscopy. ORNL - AEC - OFFICIAL M . www. .. ... O - - 5 - - - - References ORNI - AEC - OFFICIAL ORNI - AEC - OFFICIAL w 1. - See e.g. G. A. Jones, A. M. Lane and G. C. Morrison, Phys. Letters 11.,329 (1964); S. A. A. Zaidi, F. von Brentano, D. Rieck and J. P. Wurn, Phys. Letters 19, 45 (1965). * 2. D. Robson, Phys. Rev. 137, B535 (1965). See e.g. T. Tamura, Proceedings of the Conference on Isobaric Spin in Nuclear Physics, (Tallahassee, March 1966), Academic Press, to be published. T. Tan.ura, Rev. Mod. Phys. 37, 171 (1965). A.M.Lane, Phys. Rev. Letters 8 171 (1962). C. D. Kavaloski, J. S. Lilley, P. Richard and N. Stein, Phys. Rev. Letters, 16, 807 (1.966). . C. F. Moor, L. J. Parish, P, von Brentano and s. A. A. Zaidi, to be published. . ? G. Muehlehner, A. Poltoraki, w. c. Parkinson and P. H. Bassel, private communication. Captior. of Fig. 1 The 208Pb(p,p.) 208Pb and 208Pb (p,p'; 208pb* (3-) excitation functions. The experimental data shown are part of the data given in refs. 6 and 27. The theoretical curve is for 0 = 170°. The curve for 0 = 165° is only very slightly. different from those for 1700. . 2 S'+ ORNI - AEC - OFFICIAL ORNL - AEC - OFFICIAL 1 * 10 . ORNL-DWG 66 - 6845 -- ORNI - AEC - OFFICIAL 208 pbt p. O AUSTIN (470°) • SEATTLE (4659) ELASTIC SCATTERING تستمتعخشمممنتنة dolds (mb/steradian) 2.615 MeV) . be 0.30 to vinner 1 0.20 . 0.10 ngryzatim ORNL - AEC - OFFICIAL _ 13.5 14.0 15.5 16.0 16.5 14.5 15.0 ED:LAB (MeV) W . a . . . - 2 -.. . . ..: END DATE FILMED 10/21 / 66 S. .