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DWBA Analysis of Polarization of Protons from the 9Be(d p1)10Bex Reaction at Ed = 5.5 15.0 and 20

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Annalen der Physik. 7. Folge, Band 32, Heft 2,1976, S. 119-121
J. A. Barth, Leipzig
DWBA Anolyeis of Polarization of Protons from
the 9Be(d, pr)oW Reaction at b= 5.5,15.0, and 20.5 MeV
By I. I. BONDOUK
Institute of Atomic Physics, Cyclotron Laboratory, Bucharest (Romania)
With 1 Figure
Abstract
The polarization of protons from the OBe(d, p,) * O W reaction hes been analyzed in terms of the
DWBA theory at deuteron cnergiea 6.6, 16.0 and 20.6 MeV. Good fits were obtained which show
the usefulness of the DWBA theory for describing polarization by wing the optimum optical
model parameters.
Inhdtsiibersieht
Die Polarieation der Protonen nus der Reaktion #Be@,p l )
wurde im Rahmen der DWBA.
Theorie analysiert fur Deuteronenergien von 6,5; 16.0 und 20,6 MeV. Ea wurde eine gute Obereinstimmung erzielt, welche die Nutzlichkeit der DWBA-Theorie bei der Boechreibung der Polarisation zeigt, sofern die paasendsten Parameter des Optischen Modella benutzt werden.
1. Introduction
Since the famous BUTLERpaper [l], the (d, p) stripping reaction has become one
of the most extensively studied direct interaction process. A remarkable degree of
accuracy in fitting the measured differential cross section of this reaction a t least a t
forward angles with the DWBA theory has been achieved. From this analysis unambiguous determination of the orbital angular momentum transfer can be made
and the spectroscopic factors of the involved levels can be extracted. The study of
the polarimtion in the (d,p ) reaction has two niain p u p s e a : to test the reaction model
and to establish the tool for extracting information concerning the total angular
momentum of the transferred neutron. Since polarization measurements are difficult to
perform and time consuming the experimental data are rather scarce and incomplete.
Most measurements have been performed on light nuclei with widely spaced levels. They
are usually confined to the forwardangular regionswhere the cross sectionsare relatively
higher. The polarization of protons from the @Be(&,
pl)'OBeZ reaction has been measured
by different authors a t deuteron energies between 5.5 and 20.5 MeV [2-41.
BUZANOWSKI
et al. [5] measured the polarization of protons from the @Be(&,
pl)loBeZ
reaction a t Ed = 12.0 MeV and they analyzed their data in terms of the DWBA
theory. No analysis has been done for the measured polarizations a t the other energies.
I n the present work, the polarizations of protons from the gBe(d, p,)lOBez reaction
a t Ed = 5.5, 16.0 and 20.5 MeV are analyzed in terms of the DWBA theory. The
obtained results might give additional information about the reaction mechnism to
that obtained from the vector analyzing power of the same reaction [6, 71.
2.
DWBA An8lySiS
The DWBA calculations were carried out on the IBM 370/135 computer of the
Institute of Atomic Physics - Bucharest - Romania using the code DWUCK due to
KUNZ[S]. The optical potentials assumed were of the Saxon-Woode type with volume
I. I. BONDOUK
120
Table 1 Optical model parameters
reaction
channel
ref.
V,
r,
u
MeV
fm.
fm.
~
W
W'
7;
MeV MeV fm.
~~
~~
u'
fm.
~
Vao 7:
MeV fm.
~~
A deuteron [9] 160.0 0.90 0.9
12.09 2.10 0.60
7.6 1.20
B deuteron [lo] 102.0 1.16 0.72
13.46 1.72 0.69 10.0 0.9
C deuteron [6]
46.6 1.63 0.79 20.76
1.63 0.29 16.15 3.63
D proton
[ll] 63,3 1.18 0.48
20.6 1.63 0.22
0.063 1.18
E proton
[12]
63.0 1.17 0.76
10.3 1.32 0.51
6.20 1.01
F proton
[6]
66.7 1.17 0.76
11.2 1.32 0.66
6.2 1.01
a) W' values must be multiplied by 4 before inserting in the programm.
u"
7,
fm.
fm.
~~~~
0.9
0.6
0.81
0.48
0.76
0.76
1.30
1.30
1.30
1.22
1.30
1.30
(W) and surface ( W ' ) absorption. The neutron was asaumed to be captured in a potential well of the Saxon-Woods form with the spin-orbit potential of the Thomas type.
The well-depth parameter was adjusted to give the proper neutron binding energy.
The parameters of the optical potentials are collected in Table 1. All the possible combinations between the deuteron and proton parameters were tried a t the energy
5.5 MeV. Markedly better fits were obtained by the parameter set CF used to fit the
20 40 60 60 700720 740 i'60
0,
m. Megs.I
Fig. 1 DWBA f i b to the polarization for the %(d, pl)l0BeZ reaction. The solid
curvw illustrate resulta for the zero range approximation with zero cut-off radius.
The dashed curves illustrate resulta for the zero range approximation with 3fm
out-off radius
%(d, p l ) l o g e 2 Reaction
121
differential cross section and the polarization a t 12.0 MeV [5].'The fits a t 15.0 and
20.5 MeV were obtained by the same set of parameters. The results of the analysis are
shown in Fig. 1.
3. Conclusion
The present analysis of the polarization of protons from 9Be(d, p,)lOBeZ shows the
usefulness of the DWBA theory in describing the polarization using the optimum optical
iiiodel parameters. The direct interaction is the main process in the 9Be(d,p,)loBe5 reaction even a t energies as low as 5.5 MeV.
The author is indebted to Drs. A. BEBINDE
and C.HATEQAN
for their helpful
discuasions.
Thanks to Mr.D.MARIN for help in computational work.
Thanks are also due to Mrs C.MIRONfor her help in preparing the manuscript
for publication.
Roforenees
[l] S. T. BUTLEB,Proc. Roy. Soc. AW8, 659 (1961).
[2] L. H.REBEBand J. X. SALADIN,
Phys. Rev. 188 B1165 (1964).
[33 R. A. BLUE,K. J. STOUTand G. MARR, Nucl. Phys. Am, 601 (1967).
[4] J. S. VINCENT
and E. T. Bosclu~z,Proc. Second Symp. on polarization phenomena of nuc-
leons, Karlsruhe, 1965 and Beeel, Stuttgart, 1966, p. 427.
[GI A. BUZANOWSKI,
L. FBIENDL,W. KARCOZ,J. K u f i m f i s ~ ~B., EAZARSKA
and W. ZIPPER,
Nucl. Phys. A195, 280 (1972).
[GI D. FICK,R.KANKOWSKY,
K. KILLAN
and E.SALZBOBN,
Phys. Lett. 24,1603 (1970).
[7] D. H.LOYOD
and W.HABERLI,Bull. Am. Phys. Soc. 14, 37 (1969).
[81 D.KUNZ,University of Colorado, code DWUCK, version August, 1969, unpublished.
[9] D. L. POWELL,
G. M.GRAWLEY,B. V. N. RAO and B. A. ROBSON,Nucl. Phys. A147, 66
(1970).
[lo] A. DIGALOEIS,H. COBDSand J. NURZY~SRI,
Nucl. Phys. A168, 131 (1971).
[ l l ] H. R. BLIEDEN,G. M. TEMMER
and I(.L. WABSH,Nucl. Phys. 49, 209 (1963).
[12] F. D. BEOHETTI, Jr. and G. W. GREENLESS,
Phys. Rev. 182, 1190 (1969).
Bei der Fkdaktion eingegangen am 29. Min 1974.
Anschr. d. Verf.: Dr. I. I. BONDOUK
Institute of Atomic Physics. Cyclotron Laboratory, P. 0.Box 35
Bukareet (Rumiinien)
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protons, 9be, reaction, analysis, dwba, 10bex, polarization
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