Single-proton states in 155Eu

1979 ◽  
Vol 57 (2) ◽  
pp. 271-285 ◽  
Author(s):  
D. G. Burke ◽  
G. Løvhøiden ◽  
O. Straume ◽  
E. R. Flynn ◽  
J. W. Sunier
Keyword(s):  
Cross Sections ◽  
Alpha Particles ◽  
Angular Distributions ◽  
Tandem Accelerator ◽  
Analyzing Powers ◽  
Rotational Bands ◽  
Nilsson Model ◽  
Scientific Laboratory ◽  
Position Sensitive ◽  
Photographic Emulsions

The [Formula: see text] reaction was studied using 17 MeV polarized tritons from the tandem Van de Graaff accelerator at the Los Alamos Scientific Laboratory. The alpha particles were analyzed using a Q3D magnetic spectrometer and detected with a helical-cathode position-sensitive counter. The overall resolution was ~ 18 keV FWHM. Some additional exposures, performed using unpolarized tritons on a thinner target, had a resolution of ~ 12 keV FWHM and were helpful in the interpretation of a number of multiplets. Measurements of the 154Sm(α,t)155Eu reaction were made using 25 MeV alpha beams from the McMaster University tandem accelerator. The triton spectra were analyzed with a magnetic spectrograph using photographic emulsions for detectors, yielding a resolution of ~ 10 keV FWHM. By comparing the measured angular distributions of [Formula: see text] cross sections and analyzing powers with DWBA predictions it was possible to assign spins and parities to many levels. The present results confirm earlier assignments of rotational bands based on the low-lying 5/2+[413], 5/2−[532], and 3/2+[411] orbitals. In addition, states at higher excitation have now been assigned to the 1/2+[411], 1/2+[420], and 7/2+[404] orbitals, and a 3/2+[422] band is tentatively proposed. The spectroscopic strengths can be explained reasonably well by the Nilsson model when pairing and Coriolis mixing effects are included.

Odd Proton States in 165Tm, 167Tm, 169Tm, and 171Tm

1974 ◽  
Vol 52 (21) ◽  
pp. 2108-2126 ◽  
Author(s):  
H. C. Cheung ◽  
D. G. Burke ◽  
G. Løvhøiden
Keyword(s):  
Proton Transfer ◽  
Nuclear Structure ◽  
Cross Sections ◽  
Quadrupole Deformation ◽  
Angular Distributions ◽  
Coriolis Coupling ◽  
Reaction Products ◽  
Structure Factors ◽  
Nilsson Model ◽  
Photographic Emulsions

Proton states in the odd mass isotopes 165Tm, 167Tm, 169Tm, and 171Tm have been studied using (3He, d) and (α, t) reactions with 24 MeV 3He and 27 MeV 4He beams. The reaction products were analyzed with a magnetic spectrograph and detected with photographic emulsions, giving a resolution (FWHM) of 16–18 keV. The proton transfer l values were determined from (3He, d) angular distributions and from the ratios of (3He, d) and (α, t) cross sections. Nuclear structure factors, extracted using DWBA cross sections, were compared to those predicted by the Nilsson model with pairing corrections and Coriolis coupling included. Most of the previous assignments for low lying proton states have been confirmed, and several new ones were made. It is shown that the energy systematics of the intrinsic proton states cannot be attributed to variations in the quadrupole deformation, ε2, but can be explained by a small monotonic variation in the hexadecapole deformation, ε4.

A study of levels in 155Dy using the (d,t) and (3He,α) reactions

1976 ◽  
Vol 54 (12) ◽  
pp. 1258-1273 ◽  
Author(s):  
O. Straume ◽  
D. G. Burke ◽  
T. F. Thorsteinsen
Keyword(s):  
Nuclear Structure ◽  
Cross Sections ◽  
Negative Parity ◽  
Positive Parity ◽  
Angular Distributions ◽  
Coriolis Coupling ◽  
Reaction Products ◽  
Nilsson Model ◽  
Photographic Emulsions ◽  
Peak Widths

The (d,t) and (3He, α) reactions on a target of 156Dy have been used to study the nuclear structure of 155Dy. Beams of 15 MeV deuterons and 24 MeV 3He were obtained from the McMaster University FN tandem Van de Graaff accelerator. The reaction products were analyzed with an Enge-type magnetic spectrograph and detected in photographic emulsions. The (d,t) reaction was studied at 15 angles with typical peak widths (FWHM) of ~ 6 keV and (3He,α) exposures were made at 5 angles with peak widths of ~ 18 keV. The (d,t) angular distributions and ratios of the (3He,α) and (d,t) cross sections were used to determine l values for a number of transitions. It is found that the positive parity states can be described in terms of the Nilsson model when Coriolis coupling is included while for the negative parity states only the gross features are well-described this way.

Nuclear Reaction Studies of 151Sm

1973 ◽  
Vol 51 (18) ◽  
pp. 2000-2022 ◽  
Author(s):  
D. E. Nelson ◽  
D. G. Burke ◽  
J. C. Waddington ◽  
W. B. Cook
Keyword(s):  
Cross Sections ◽  
Coulomb Excitation ◽  
Negative Parity ◽  
Angular Distributions ◽  
Neutron Transfer ◽  
Reaction Products ◽  
Single Neutron ◽  
Nilsson Model ◽  
Nuclear Levels ◽  
Photographic Emulsions

Properties of nuclear levels in 151Sm have been studied by measuring angular distributions for the 152Sm(d,t)151Sm reaction and spectra at several angles for the 152Sm(3He,α)151Sm and 150Sm(d,p)151Sm reactions. The reaction products were analyzed with a magnetic spectrograph and detected with photographic emulsions. Transfer l values were deduced from the (d,t) angular distributions and from the ratios of (3He,α) and (d,t) cross sections. The (d,t), (d,p), and (3He,α) reactions on targets of 151Sm were also studied in order to learn more about the wave function of the 151Sm ground state. The low-lying positive parity levels can be described by the Nilsson model with Coriolis and ΔN = 2 interactions included. However, the properties of the low energy negative parity states could not be explained as easily. No mixture of Nilsson states was found which could simultaneously explain the single neutron transfer intensities and the Coulomb excitation probabilities from previous measurements.

A Study of Levels in 149Nd using the (d, t) and (3He, α) Reactions

1973 ◽  
Vol 51 (4) ◽  
pp. 455-464 ◽  
Author(s):  
D. G. Burke ◽  
J. C. Waddington ◽  
D. E. Nelson ◽  
J. Buckley
Keyword(s):  
Cross Sections ◽  
Ground State ◽  
State Transition ◽  
Angular Distributions ◽  
Ground State Transition ◽  
Reaction Products ◽  
Q Value ◽  
Nilsson Model ◽  
Photographic Emulsions ◽  
Peak Widths

Triton spectra from the 150Nd(d, t)149Nd reaction have been measured at 15 angles using beams of 12 MeV deuterons. The 150Nd(3He, α)149Nd reaction was studied at four angles with 24 MeV 3He beams. In all cases the reaction products were analyzed with an Enge-type magnetic spectrograph and detected with photographic emulsions. The peak widths (FWHM) were approximately 8 keV for the (d, t) studies and 25 keV for the (3He, α) spectra. It is now evident that the highest energy triton group ascribed to the 150Nd(d, t)149Nd reaction in previous works does not correspond to the ground state transition. According to the current interpretation the ground state transition has a Q value of −1.122 ± 0.010 MeV. The (d, t) angular distributions and the ratios of (3He, α) and (d, t) cross sections at selected angles were used to determine l values for a number of the transitions. Three states in 149Nd at 481, 813, and 986 keV are definitely populated by l = 0 transitions and thus have Iπ = 1/2+. A strongly perturbed band consisting of a mixture of Nilsson states from the i13/2 shell has been found, with properties similar to the corresponding bands in the isotones 151Sm and 153Gd. The total observed intensity for each of the l values 0, 1, 2, and 6 cannot be explained by the extreme single-particle shell model but is consistent with that predicted by the Nilsson model. However, the splitting of the strength among the observed states cannot be explained by the basic Nilsson model.

A Study of Levels in 153Gd Using the (d,t) and (3He,α) Reactions

1973 ◽  
Vol 51 (22) ◽  
pp. 2354-2368 ◽  
Author(s):  
G. Løvhøiden ◽  
D. G. Burke
Keyword(s):  
Cross Sections ◽  
Negative Parity ◽  
Positive Parity ◽  
Angular Distributions ◽  
Reaction Products ◽  
Ground State Band ◽  
Intensity Pattern ◽  
Nilsson Model ◽  
State Band ◽  
Photographic Emulsions

Triton spectra from the 154Gd(d,t)153Gd reaction have been measured at 15 angles using a beam of 15 MeV deuterons. The 154Gd(3He,α)153Gd reaction was studied at 4 angles with a 24 MeV 3He beam. The reaction products were analyzed with an Enge-type magnetic spectrograph and detected with photographic emulsions. The (d,t) angular distributions and ratios of the (3He,α) and (d,t) cross sections were used to determine l values for a number of transitions. Members of the strongly perturbed band consisting of a mixture of Nilsson states from the i13/2 shell have been populated. An attempt has been made to describe some of the positive parity states in terms of the Nilsson model with Coriolis and ΔN = 2 mixings included. As spin assignments are now available for a large number of positive parity levels, it is possible to see a better developed pattern for this mixing than was presented previously. Although the observed intensity pattern for the 3/2−[521] ground-state band agrees with expectations, the remaining negative parity states cannot be easily explained in terms of the basic Nilsson model.

Systematic nonlocal optical model potential for nucleons

2015 ◽  
Vol 24 (01) ◽  
pp. 1550006 ◽  
Author(s):  
Yuan Tian ◽  
Dan-Yang Pang ◽  
Zhong-Yu Ma
Keyword(s):  
Cross Sections ◽  
Optical Model ◽  
Model Potential ◽  
Nucl Phys ◽  
Angular Distributions ◽  
Model Calculations ◽  
Analyzing Powers ◽  
Optical Model Potential ◽  
Fitting Procedures ◽  
Scattering Cross Sections

Based on the Perey–Buck nonlocal optical model potential, F. Perey and B. Buck, Nucl. Phys. 32 (1962) 353, we obtain a new set of nonlocal optical model potential (NLOMP) parameters for proton and neutron scattering off nuclei. The experimental angular distributions of nucleon scattering off nuclei ranging from 27 Al to 208 Pb with incident energies around 10 MeV to 30 MeV are adopted in the fitting procedures. This NLOMP is energy independent. The chi-squares χ2 obtained in the fittings are comparable to those from the KD03 phenomenological local optical model potentials (OMP) A. Koning and J. Delaroche, Nucl. Phys. A 713 (2003) 231. Good agreement is found in comparisons between optical model calculations using this NLOMP and KD03 in their reproduction to the experimental angular distributions of elastic scattering cross-sections and analyzing powers.

A STUDY OF THE Be9(He3, n)C11 REACTION

1963 ◽  
Vol 41 (7) ◽  
pp. 1036-1046 ◽  
Author(s):  
L. van der Zwan ◽  
A. T. Stewart ◽  
J. Y. Park ◽  
E. Merzbacher
Keyword(s):  
Compound Nucleus ◽  
Cross Sections ◽  
Interaction Mechanism ◽  
Direct Interaction ◽  
Particle Energy ◽  
Energy Spectra ◽  
Angular Distributions ◽  
Proton Recoil ◽  
The Cross ◽  
Photographic Emulsions

The energy spectra and angular distributions of the emergent neutrons from the Be9(He3, n)C11 reaction have been obtained for an incident He3-particle energy of 2 Mev with the technique of observing proton recoil in photographic emulsions. The cross sections were normalized to Be9(He3, p)B11 data observed simultaneously at 90° to the beam. The lack of similarity in the (He3, n) and (He3, p) mirror reactions to some residual states suggests a direct interaction mechanism rather than compound nucleus. An attempt to analyze some of the data in terms of double particle stripping has been made.

scholarly journals On the Experimental Investigation of the Angular Distributions in the Reaction 112Cd(p,γ)113In

2019 ◽  
Vol 26 ◽  
pp. 188
Author(s):  
A. Zyriliou ◽  
A. Khaliel ◽  
T. J. Mertzimekis
Keyword(s):  
Cross Sections ◽  
Nuclear Physics ◽  
Gamma Ray ◽  
Reaction Cross ◽  
Angular Distributions ◽  
Special Focus ◽  
Tandem Accelerator ◽  
Section Data ◽  
Hpge Detectors ◽  
Low Energies

Some of the mid–weight nuclei lie in the region of the isotopic chart where the astrophysical p-process has a prominent role in the nucleosynthetic scenarios. Experimentally deduced reaction cross section data can provide stringent tests for the astrophysical models, especially at low energies. In this framework, the reaction 112Cd(p,γ)113In has been studied experimentally at four proton beam energies 2.8 ≤ Ep≤ 3.4 MeV, partly inside the astrophysically interesting Gamow window. Proton beams were provided by the 5.5 MV T11 Van de Graaff Tandem Accelerator of the Institute of Nuclear Physics of the National Center for Scientific Research (NCSR) “Demokritos”. In–beam spectroscopy was carried out with an array of four HPGe detectors sitting on a rotating table. In total, eight (8) different angles were used to record gamma–ray spectra. Special focus was given on constructing the angular distribution of each gamma–ray feeding the ground state of 113In directly, so as to determine the reaction cross sections from the in–beam data, exclusively. The resulting cross sections were compared to Hauser–Feshbach calculations using the code TALYS v1.9.

Proton States in 155Tb, 157Tb, 159Tb, and 161Tb

1972 ◽  
Vol 50 (24) ◽  
pp. 3152-3171 ◽  
Author(s):  
J. C. Tippett ◽  
D. G. Burke
Keyword(s):  
Cross Sections ◽  
Rotational Level ◽  
The State ◽  
Alpha Particles ◽  
Particle State ◽  
Reaction Products ◽  
Proton Transfers ◽  
Spectroscopic Factors ◽  
I 11 ◽  
Photographic Emulsions

Proton states in the odd terbium isotopes 155Tb, 157Tb, 159Tb, and 161Tb have been studied using (3He,d) and (α,t) reactions. The beams of 24 MeV 3He and 25 MeV alpha particles were produced by the McMaster University model FN tandem Van de Graaff accelerator. The reaction products were analyzed with an Enge split-pole magnetic spectrograph and detected with photographic emulsions. The ratios of cross sections in the (3He,d) and (α,t) reactions were used as an indication of the/values for the proton transfers, and the spectroscopic factors were extracted using DWBA calculations. The results of the present work confirm the assignments of the 3/2+ [411] and 5/2+[413] Nilsson orbitals in all four isotopes. The I = 11/2 states of the 5/2−[532] and 7/2−[523] orbitals were identified in 161Tb and 159Tb and their assignments confirmed in 157Tb and 155Tb. It was necessary to invoke appreciable Coriolis mixing between these two orbitals in order to describe the observed rotational level spacings and the spectroscopic strengths. The assignments of the 7/2+[404] orbital were confirmed in 155Tb and 157Tb and this orbital was identified in 159Tb and 161Tb. Previous assignments of the 1/2+ [411] particle state with vibrational admixtures were confirmed in 157Tb and 159Tb and the state was identified in 161Tb. The present results support earlier evidence for the existence of a second fragment of the 1/2+[411] orbital in 159Tb and suggest the presence of a similar state in 157Tb. In each of the isotopes the 5/2+[402] orbital was assigned and a tentative assignment for the 1/2−[541] orbital was proposed.

States in the N = 87 Nuclei 149Sm and 151Gd Populated by the (d, t) and (3He,α) Reactions

1975 ◽  
Vol 53 (12) ◽  
pp. 1182-1192 ◽  
Author(s):  
G. Løvhøiden ◽  
D. G. Burke
Keyword(s):  
Spherical Shell ◽  
Shell Model ◽  
High Spin ◽  
Cross Sections ◽  
Striking Feature ◽  
Angular Distributions ◽  
Spin States ◽  
Reaction Products ◽  
Photographic Emulsions

The (d, t) and (3He, α) reactions on targets of 150Sm and 152Gd have been studied using a magnetic spectrograph and photographic emulsions to analyze and detect the reaction products. The (3He, α) spectra were measured at two angles for each target using 24 MeV beams of 3He. The 150Sm(d, t)149Sm reaction was studied at 13 angles with 12 MeV deuterons. The 152Gd(d, t)151Gd spectra were recorded at 4 angles with 15 MeV deuterons. The l values for a number of low spin states were determined from the (d, t) angular distributions. The ratios of (3He, α) and (d, t) cross sections were used to obtain l values for several other states. It is possible to explain the observed strength in terms of the spherical shell model although there is fragmentation of the spherical states. One striking feature is the similarity in the structures of the two nuclei. In both 149Sm and 151Gd there are high spin i13/2 states at ~0.85 MeV and h11/2 states at ~1.25 MeV.

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