Boschitz, E.T.

Chabre, M.

Conzett, H.E.

Shield, E.

Slobodrian, R.J.

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Lawrence Berkeley National LaboratoryRecent WorkTitlePOLARIZATION IN p-He4 SCATTERING BETWEEN 27 AND 63 MeVPermalinkhttps://escholarship.org/uc/item/7h8470f4AuthorsBoschitz, E.T.Chabre, M.Conzett, H.E.et al.Publication Date1965-08-01eScholarship.org Powered by the California Digital LibraryUniversity of CaliforniaUCRL-16216 University of California Ernest 0. Radiation lawrence Laboratory POLARIZATION IN p-He 4 SCATTERING BETWEEN 27 AND 63 MeV TWO-WEEK LOAN COPY This is a library Circulating Copy which may be borrowed for two weeks. For a personal retention copy. call Tech. Info. Dioision, Ext. 5545 Berkeley, California DISCLAIMER This document was prepared as an account of work sponsored by the United States Government. While this document is believed to contain correct information, neither the United States Government nor any agency thereof, nor the Regents of the University of California, nor any of their employees, makes any warranty, express or implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by its trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or the Regents of the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof or the Regents of the University of California. '· l .. •' ·< <-· . ~: ":' ' · .. · .. -. :.,, '·~ ,·1 ... . ·, ••• ,I •' ._; ·~ ·, •j I, ·' ... ·.· ~·.' , .. ·, f ',., .. 1 . ' ·, ··:·i .. ,·, ·~"··:-··· :···, : ',; UNIVERSITY OF CALIFORNIA Lawrence Radiation Laboratory .. Berkeley, California ., AEC Contract No. W-74o5..,eng-48 ·.;.· UCRL-16216 FE. -':r • Boschitz]-M. Chabr~, H •. E. Conzett, E~ Shield, and R. J. Slobodrian . · .. August 1965 :' ,.-·:,· •,:·.· •·'•, ·, '•', ... . ,·1' -.··.-·, ~ ·' . Paper presented. at Int~rne.tional. Conferenqe ori- Polarization Phenomena of · . . ' '. . ~. . Nuclecms, Kernforschungszentrum Karlsruhe~ September ·6-10, 1965. '·" ',:,l ~\ . ,. " ·., . . . . . 4 * POLARIZATION IN p-He SCATTERING BETWEEN 27 AND. 63 MeV t . '* -E, ·T. Boschitz, M. Chabre, H. E. Conzett, E. Shield, and R. J. Slobodrian Lawrence Radiation Laboratory University of California Berkeley, California ·Using the polarized-proton facility at the Berkeley 88-inch cyclotron, we have measured the asymmetries in the elastic scattering of polarized protons 4 from He at energies of 26.8, 34.2, 44.1, 54.8, and 63.3 MeV. These energies were selected so that-experimental results would then be available at approxi-mately 5-MeV intervals over the region 10 to 63 MeV, the latter being _the maxi-mum energy available at this facility. With the beam polarization P1 known . I from ~xperimental results, we then determined from the measured asymmetries E(E,e) the polarizations P(E,e) = E(E,e)jP1• A phase-shift analysis of these and other data available throughout this energy range has been started, and ~e report here preliminary results of this analysis. Figure 1 shows our data along with those from the Rutherford Laboratory at 29, 4o, and 48 Me~) and 21-MeV data from Berkeley2 ). The polarizations calculated from the phase-shift solutions are also shown. Available or inter-4) polated differential cross-section data3 ' were included-in the analysis at all energies, although such data at 66 MeV were limited to c.m. angles forward of 60°. The 55-MeV polarization results show a continuation of the trend estab-lished with the lower energy data, and they are in substantial disagreement with the polarization calculat~d by Kanada and Horikawa5? from phase s~ifts ' .• 4) derived from analysis of 55-MeV differential cross section data ·• Their calculated P(e) has three maxima, of values approximately +o.37, -0.77, and +0.93 near c.m. angtes of 50, 95, and 125 degrees, respectively . .. · ,, 'j Figure 2 shows our preliminary phase-shift results. We use the nota-,. + +t ~ . th ~; exp(2i5;) fbr the (complex) amplitude of the outgoing l partial tion -2-... ' '. . :: . : ·~. . . + + -wave, so that T} · (T};) and 51 (5~), the absorption parameter and nuclear phase shift for the j = 1+ 1/2 (j = 1-1/2) state, are real. The smooth curves show ± .· .the_general _energy dependence.of the 51, although the actual preliminary values show some scatter about these curves. Until further more complete searches are made, we do not.ascribe physical significance to the slightly oscillatory be~ havior of'5i and 5~ near and above 40 MeV. As is seen in the table listing the + values of T}~, there are accompanying variations in these parameters in the same energy region. This behavior is not to be expected because all possible'reaction thresholds occur at lower energies, and so a smoother behavior would be more plausible •. The arrows at 22.9 and 35.2 MeV in Fig. 2 mark the threshold for the first reaction channel, going to d+3Re, and the energy at which all channels are ::open; the last being the 3p+2n five-body channel. In this energy interval J.he absorption appears to be strongest in the 1 = 2 (j = 5/2) partial wave, with appreciable absorption also taking place in the 1 = 1 (j = 1/2) and 1• = 3 (j = 7/2) waves. We see no evidence of threshold effects, but data more closely spaced in energy would be required in order. to study such questions. . 1 We are grateful to A. W. Stetz for providing the.computer program for phase-shift analysis and to W. F. Tivol for his considerable efforts in de-pugging and running the program. _,. ·' \ . / -3- UCRL-16216 FOOTNOTES AND REFERENCES * . . . .. This work was performed .under the auspices ofthe U. S. Atomic Energy Commission. t . . . ·On leave from NASA Lewis Research.Center, Cleveland, Ohio., * NATO fellow on ~eave from CNRS, Institut Fourier, Grenoble, France. l. 2. M. K. Craddock, R. C. Hanna, L. P. Robertson and B. W. Davies, Phys. Letters L' 335.(1963); P. L. A. Progress Report, NIPL/R/60, 44, 1963. H. E. Conzett, G. Igo, and A. Nir, private communication. P. W., Allison, Thesis, University of Colorado, 1964;. S. M. Bunch, H. H. Forster,. and C. C. Kim, NucL Phys. 53, 241 (1964); M. K. Brussel and J. Williams, Phys. Rev .. 89, 422 (1953); B. W. Davies, M. K, Craddock, R. C. Hanna, L. p, Robertsonland R. E. Shamu, P. L .. A. Progress Report, NIRL/R/81; 69, 1964; A. M. Cormock, J.,;\N. Palmieri, N. F. Ramsey and Richard Wilson, Phys. ,: Rev. 115, 599 ( l9b9) . · ' ~ 4. S. Hayakawa, N. Hbrikawa, R. Kajikawa, K. Kikuchi, H. Kobayakawa, ~:~ ~ . • K. Matsuda, S. NAkata andY. Sumi., ;j, Phys. Soc. Japan 19, 2004 (1964). li ' 5. H. Kanada and N. Horikawa, Nagoya University, Physics Department Report T-5, March 1965., ., -4-. ' FIGURE CAPriONS . 4 'ig.· ·1. Polarization ~(e) irr p- He elastic scattering. · UCRL-16216 I , The dots are the experimental aata ( referenc_es . in text). The curves represent values calculated in this analysis. Fig. 2. · Phase-shift paramete~s from preliminary analysis of the data. The symbols are ·defined in the text • .. \ . I . ·; ·;· , ..• , r'' ·1-. -5-0.5 ec.m. (deg) MUB-7490 (J Fig. 1 · -6-Fig. 2 , This report was prepared as an account of Government sponsored work. Neither the United States, nor the Com-m1ss1on, nor any person acting on behalf of the Commission: A. Makes any warranty or representatio.n, expressed or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this report, or that the use of any information, appa-ratus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of any infor-mation, apparatus, method, or process disclosed in this report. As used in the above, "person acting on behalf of the Commission" includes any employee or contractor of the Com.,. mission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employee of such contractor prepares, disseminates, or provides access t6, any information pursuant to his employment or contract with the Commission, or his employment with such contractor. 0 

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POLARIZATION IN p-He4 SCATTERING BETWEEN 27 AND 63 MeV

https://escholarship.org/uc/item/7h8470f4

POLARIZATION IN p-He4 SCATTERING BETWEEN 27 AND 63 MeV

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