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 Nuclear disintegrations produced by cosmic rays

1949 ◽  
Vol 196 (1046) ◽  
pp. 325-343 ◽  
Keyword(s):  
Cosmic Radiation ◽  
High Energy ◽  
Energy Spectra ◽  
Angular Distributions ◽  
Excitation Energies ◽  
Wide Range ◽  
High Energy Tail ◽  
Energy And Angular Distributions ◽  
Photographic Emulsions ◽  
Α Particles

Measurements have been made on the energy and angular distributions of the charged particles from disintegration ‘stars’ produced in the silver and bromine nuclei of photographic emulsions exposed to cosmic radiation. The observations extended over a wide range of excitation energies (100 to 700 MeV). The energy spectra and angular distributions of the protons can be explained in all cases by simple evaporation theory. This energy distribution shows also a high-energy tail consisting of direct knock-on protons and slow mesons. At high excitation energies the α-particles exhibit collimation effects which are probably due to localized ‘boiling’ or a form of fission.

COLD FUSION REACTIONS USING NEUTRON-RICH PROJECTILES

2013 ◽  
Vol 22 (08) ◽  
pp. 1350061 ◽  
Author(s):  
A. SULAKSONO
Keyword(s):  
Cross Section ◽  
Compound Nucleus ◽  
Cross Sections ◽  
Estimation Method ◽  
Cold Fusion ◽  
Evaporation Residue ◽  
Fusion Reactions ◽  
Fusion Barrier ◽  
The Cross ◽  
Evaporation Residues

This paper studies the formation cross-sections of super heavy (SH) nuclei in some cold fusion reactions of radioactive neutron-rich projectiles with double-magic 208 Pb target. In this study, the cross-sections of capture, fusion and evaporation residues in one- and two-neutron (1n and 2n) channels are calculated by using neutron-rich Fe , Ni and Zn projectiles are compared to the cross-sections calculated using stable Fe , Ni and Zn projectiles. The heights of fusion barrier and their positions in all reactions considered in this study are also compared to the heights and positions calculated using the estimation method proposed by Dutt and Puri. For cold fusion reactions with stable Fe , Ni and Zn projectiles, the heights of fusion barrier and the cross-sections of evaporation residues in 1n and 2n channels are compared to their corresponding experimental data. In general, for reactions using projectiles with the same proton number, the neutron-rich projectile is found to yield relatively-heavier mass of SH nucleus and larger evaporation residue cross-section, compared to those of the corresponding stable projectiles. However, in certain reactions, the cross-sections of neutron-rich projectile can be slightly larger or slightly smaller than that of the corresponding stable projectile. This behavior is highly affected by the charge of projectile and the fission barrier of the formed compound nucleus (CN). In addition, the 292114 is found to be the heaviest compound nucleus formed in cold fusion reaction by using neutron-rich nuclei as the projectile, but the cross-section of evaporation residue in one-neutron channel is still around few pico barns (pb).

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.

Decay of the112Sn compound nucleus: Excitation functions of evaporation residues, energy spectra, and angular distributions of evaporated protons and alphas

1997 ◽  
Vol 56 (5) ◽  
pp. 2582-2596 ◽  
Author(s):  
Bency John ◽  
S. K. Kataria ◽  
B. S. Tomar ◽  
A. Goswami ◽  
G. K. Gubbi ◽  
...  
Keyword(s):  
Compound Nucleus ◽  
Energy Spectra ◽  
Angular Distributions ◽  
Excitation Functions ◽  
Evaporation Residues

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.

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.

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.

Reaction mechanism of the 16O + d reactions

1970 ◽  
Vol 48 (19) ◽  
pp. 2235-2253 ◽  
Author(s):  
N. E. Davison ◽  
W. K. Dawson ◽  
G. Roy ◽  
W. J. McDonald
Keyword(s):  
Experimental Data ◽  
Compound Nucleus ◽  
Cross Sections ◽  
Direct Interaction ◽  
Scattering Data ◽  
Orbit Potential ◽  
Spectroscopic Factors ◽  
Theoretical Predictions ◽  
Using Data ◽  
Good Agreement

The reactions 16O(d,d)16O, 16O(d,p)17O, and 16O(d,n)17F have been studied in the deuteron energy range 4.00–6.00 MeV in order to determine to what extent current theories can satisfactorily describe these reactions. It was found that the theoretical curves from both the optical and DWBA models fit the experimental data significantly better when the deuteron optical-model potentials had been obtained using a spin–orbit potential in the analysis of the elastic scattering data. Spectroscopic factors obtained for the ground and first-excited states of 17O and 17F using the DWBA theory are in satisfactory agreement with theoretical predictions and with values obtained by previous workers. Small, but nonzero, spectroscopic factors have been obtained for the states at 3.058 and 3.846 MeV excitation in 17O using data measured in this work and in previous experiments. The sum of the calculated direct interaction and compound-nucleus cross sections is in good agreement with experimental data for all states studied, whether they were populated primarily by direct or compound-nucleus reactions. The calculated compound-nucleus lifetimes are also in agreement with values obtained from an analysis of the fluctuations in the yield curves.

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