Nonequilibrium effects in α-particle-induced reactions in Cs and I

2000 ◽  
Vol 78 (2) ◽  
pp. 133-139 ◽  
Author(s):  
M K Bhardwaj ◽  
I A Rizvi ◽  
A K Chaubey
Keyword(s):  
Cross Sections ◽  
Gamma Ray ◽  
Theoretical Calculations ◽  
High Energy ◽  
Particle Energy ◽  
Substantial Contribution ◽  
Equilibrium Geometry ◽  
Activation Technique ◽  
Excitation Functions ◽  
Stacked Foil Activation Technique

The excitation functions for the reactions 127I(α,n)130Cs, 127I(α,2n)129Cs, 127I(α,4n)127Cs, 133Cs(α,2n)135La, and 133Cs(α,4n)133La have been measured up to 50 MeV alpha-particle energy using the stacked-foil activation technique and Ge(Li) gamma-ray spectroscopy. The measured cross sections were compared with theoretical calculations considering equilibrium as well as the pre-equilibrium geometry-dependent hybrid models of Blann. The high-energy tails of the excitation functions show a substantial contribution from pre-equilibrium emission. A general agreement is observed between the experimental results and theoretical predictions with an initial exciton configuration n0 = 4(2n + 2p + 0h).PACS No. 25.40-h

EXCITATION FUNCTIONS OF α-INDUCED REACTIONS IN COBALT AND PRE-EQUILIBRIUM EFFECTS

2004 ◽  
Vol 13 (03) ◽  
pp. 585-595 ◽  
Author(s):  
M. AFZAL ANSARI ◽  
MOUNER A. Abd. ALSLAM ◽  
N. P. M. SATHIK ◽  
M. ISMAIL ◽  
M. H. RASHID
Keyword(s):  
Experimental Data ◽  
Reaction Mechanism ◽  
Theoretical Calculations ◽  
Particle Energy ◽  
Activation Technique ◽  
Thermodynamical Equilibrium ◽  
Excitation Functions ◽  
Model Code ◽  
A Value ◽  
Stacked Foil Activation Technique

Excitation functions for the reactions (α,2n), (α,αn), (α,α2n), (α,α3n) and (α,2pn) have been measured using 57 Co as a target up to 50 MeV α-particle energy. The stacked foil activation technique and γ-ray spectroscopy method has been employed. Measured excitation functions are compared with the geometry dependent hybrid (GDH) model. A comparison shows that the pure equilibrium (EQ) compound reaction mechanism is incapable of reproducing the experimental data while the pre-equilibrium (PE) reaction mechanism along with equilibrium (EQ) decay, where it is considered that pre-equilibrium emission of particles take place prior to the establishment of the thermodynamical equilibrium of the system, is able to reproduce the experimental data. The GDH model code ALICE-91 has been used for theoretical calculations. A value of initial exciton number n0=4 with configuration (2 neutron + 2 proton + 0 hole) has been found to give the satisfactory reproduction of experimental excitation functions.

Non-equilibrium emission of neutrons in α-particle induced reactions with holmium

2008 ◽  
Vol 86 (3) ◽  
pp. 495-500 ◽  
Author(s):  
Avinash Agarwal ◽  
I A Rizvi ◽  
A K Chaubey
Keyword(s):  
Compound Nucleus ◽  
Computer Code ◽  
High Energy ◽  
Activation Technique ◽  
Excitation Functions ◽  
Equilibrium Reaction ◽  
Experimental Trend ◽  
Γ Ray ◽  
Stacked Foil Activation Technique ◽  
Equilibrium Emission

The stacked-foil activation technique followed by off line high-purity Ge γ-ray spectroscopy was used for the measurement of the excitation functions for energies up to 50 MeV for the 165Ho(α, 2n) 167Tm, 165Ho(α, 3n) 166Tm, and 165Ho(α, 4n) 165Tm reactions. The measured excitation functions were compared with theoretical predications considering equilibrium as well as pre-equilibrium reaction mechanisms according to the geometry-dependent hybrid (GDH) model of Blann using computer code ALICE-91. The high-energy parts of the excitation functions are due to the pre-equilibrium reaction mechanism, while the low-energy parts are mediated by compound-nucleus decay. It was found that the compound-nucleus-decay mechanism alone is unable to explain the experimental trend of our data. The pre-equilibrium fraction was also calculated. PACS Nos.: 22.55.–e, 27.60.+j

Analysis of the excitation function of alpha-particle-induced reactions on natural silver

1996 ◽  
Vol 74 (9-10) ◽  
pp. 618-625 ◽  
Author(s):  
H. B. Patel ◽  
M. S. Gadkari ◽  
Bhruna Dave ◽  
N. L. Singh ◽  
S. Mukherjee
Keyword(s):  
Cross Sections ◽  
Gamma Ray ◽  
Residual Nucleus ◽  
Reaction Cross ◽  
Activation Technique ◽  
Individual Reaction ◽  
Reaction Channels ◽  
Stacked Foil Activation Technique ◽  
The Individual ◽  
Reaction Cross Sections

Excitation functions of the reactions 107Ag[(α, n); (α, 2n); (α, αn); (α, α2n)] and,109Ag[(α, 2n); (α, 3n); (α, 4n); (α, α3n); (α, α4n)] were investigated up to 70 MeV by the stacked foil activation technique and Ge(Li) gamma-ray spectroscopy method. Since the natural silver used as the target has two odd mass stable isotopes of abundance 51.83% (107Ag) and 48.17% (109Ag), their activation in some cases gives the same residual nucleus through different reaction channels, but with very different Q values. In such cases, the individual reaction cross sections are separated with the help of the ratio of theoretical cross sections. The experimental cross sections were compared with the predictions of a pre-equilibrium hybrid model. The (α, xn) reactions are fairly well reproduced with initial exciton number n0 = 4(4p0h), whereas (α, αxn) reactions are underestimated in magnitude by a factor of five to six.

scholarly journals Investigation of cross sections of deuteron induced nuclear reactions on selenium up to 50 MeV

2021 ◽  
Vol 57 (4) ◽  
Author(s):  
Ferenc Tárkányi ◽  
Sándor Takács ◽  
Ferenc Ditrói ◽  
Zoltán Szűcs ◽  
Károly Brezovcsik ◽  
...  
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Gamma Ray ◽  
Nuclear Reactions ◽  
Particle Energy ◽  
Gamma Ray Spectrometry ◽  
Excitation Functions ◽  
On Line ◽  
Theoretical Model Codes ◽  
Activation Cross Sections

AbstractIn the frame of a systematic study of deuteron induced nuclear reactions on all elements, activation cross sections on $$^{\mathrm {nat}}$$ nat Se were investigated. Excitation functions were measured up to 50 MeV particle energy for production of $$^{\mathrm {82}}$$ 82 Br(m$$+)$$ + ) ,$$^{\mathrm {80m}}$$ 80 m Br, $$^{\mathrm {77}}$$ 77 Br(m$$+)$$ + ) ,$$^{\mathrm {76}}$$ 76 Br(m$$+)$$ + ) , $$^{\mathrm {75}}$$ 75 Br, $$^{\mathrm {75}}$$ 75 Se(cum), $$^{\mathrm {73}}$$ 73 Se(cum), $$^{\mathrm {76}}$$ 76 As,$$^{\mathrm {74}}$$ 74 As, $$^{\mathrm {73}}$$ 73 As(cum), $$^{\mathrm {72}}$$ 72 As and $$^{\mathrm {71}}$$ 71 As(cum) by using the activation method through stacked foil irradiation followed by off-line gamma-ray spectrometry. The experimental results were compared to the earlier experimental data and to excitation functions calculated with the ALICE-D and EMPIRE-D theoretical model codes and data given in the TENDL-2019 on-line library based on TALYS calculations.

STUDY OF EXCITATION FUNCTIONS IN Rh(α, xn) Ag REACTIONS

1996 ◽  
Vol 05 (02) ◽  
pp. 345-352 ◽  
Author(s):  
M. AFZAL ANSARI ◽  
N.P.M. SATHIK ◽  
B.P. SINGH ◽  
M.G.V. SANKARACHARYULU ◽  
R. PRASAD
Keyword(s):  
Experimental Data ◽  
Compound Nucleus ◽  
Alpha Particle ◽  
Computer Code ◽  
Particle Energy ◽  
Activation Technique ◽  
Excitation Functions ◽  
Foil Activation ◽  
Alpha Particle Energy ◽  
Stacked Foil Activation Technique

The excitation functions for the reactions 103 Rh (α, n)106 m Ag , 103 Rh (α, 2n)105 Ag , and 103 Rh (α, 3n)104 Ag have been measured between 10 and 40 MeV alpha-particle energy, using the stacked foil activation technique. Excitation functions are also calculated theoretically using the Geometry Dependent Hybrid (GDH) model. The computer code ALICE/LIVERMORE-82 has been used which takes into account the pre-equilibrium contribution along with the equilibrium decay of the compound nucleus. It has been found that initial exciton number n0=4 gives a satisfactory reproduction of experimental data.

Measurement and analysis of excitation functions for alpha-particle-induced reactions in rhenium

2004 ◽  
Vol 82 (3) ◽  
pp. 227-237
Author(s):  
N L Singh ◽  
M S Gadkari
Keyword(s):  
Cross Sections ◽  
Residual Nucleus ◽  
Reaction Cross ◽  
Activation Technique ◽  
Excitation Functions ◽  
Theoretical Predictions ◽  
Reaction Channels ◽  
Stacked Foil Activation Technique ◽  
The Individual ◽  
First Time

Excitation functions of the reactions 185Re[(α,n); (α,2n); (α,3n)] and 187Re[(α,n); (α,2n); (α,3n); (α,4n)] were investigated up to 50 MeV using the stacked-foil activation technique and high-purity germanium γ-ray spectroscopy method. Since the natural rhenium used as a target has two odd-mass stable isotopes of abundance 37.4% (185Re) and 62.6% (187Re), their activation in some cases gives the same residual nucleus through different reaction channels, but with very different Q values. In such cases, the individual reaction cross sections are separated with the help of the ratio of theoretical cross sections. The experimental cross sections were compared with the theoretical predictions considering equilibrium as well as pre-equilibrium contributions using code ALICE/90. It was found that the initial exciton configuration n0 = 4 (4p0h) appears to give a good fit to the experimental data. To the best of our knowledge, the excitation functions for 185Re[(α,n); (α,2n); (α,3n)] and 187Re[(α,3n); (α,4n)] reactions were measured for the first time. PACS No.: 25.55.–e

Cross sections for d-3H neutron interactions with samarium isotopes

2016 ◽  
Vol 104 (8) ◽  
Author(s):  
Junhua Luo ◽  
Chunlei Wu ◽  
Li Jiang ◽  
Long He
Keyword(s):  
Experimental Data ◽  
Neutron Flux ◽  
Cross Sections ◽  
Theoretical Calculations ◽  
Nuclear Model ◽  
Activation Technique ◽  
Incident Neutron ◽  
Reaction Threshold ◽  
Talys 1.6 ◽  
The Cross

Abstract:The cross sections for (n,x) reactions on samarium isotopes were measured at (d-T) neutron energies of 13.5 and 14.8 MeV with the activation technique. Samples were activated along with Nb and Al monitor foils to determine the incident neutron flux. Theoretical calculations of excitation functions were performed using the nuclear model codes TALYS-1.6 and EMPIRE-3.2 Malta with default parameters, at neutron energies varying from the reaction threshold to 20 MeV. The results were discussed and compared with experimental data found in the literature. At neutron energies 13.5 and 14.8 MeV, the cross sections of the

Nonequilibrium effects in α-particle induced reactions on gallium isotopes

1989 ◽  
Vol 67 (9) ◽  
pp. 870-875 ◽  
Author(s):  
I. A. Rizvi ◽  
M. K. Bhardwaj ◽  
M. Afzal Ansari ◽  
A. K. Chaubey
Keyword(s):  
Cross Sections ◽  
Residual Nucleus ◽  
Reaction Cross ◽  
Activation Technique ◽  
Individual Reaction ◽  
Reaction Channels ◽  
Stacked Foil Activation Technique ◽  
The Individual ◽  
Reaction Cross Sections

The stacked foil activation technique and Ge(Li) γ-ray spectroscopy have been employed for the determination of the excitation functions, up to 60 MeV, of six reactions, 69Ga(α,n), (α,2n), (α,3n), (α,p3n); 71Ga(α,n) and (α,4n). Since natural gallium used as the target has two odd-mass stable isotopes of abundance, 69Ga(60.1%) and 71Ga(39.9%), their activation in some cases gives the same residual nucleus through different reaction channels, but with very different Q values. In such cases, the individual reaction cross sections are separated with the help of the ratio of their theoretical cross sections. A preliminary theoretical comparison with the preequilibrium geometry-dependent hybrid (GDH) model has been done using an initial exciton number no = 4 (2n + 2p + 0h), and general agreement was found for all reactions at high energies.

ALPHA-INDUCED REACTIONS IN ANTIMONY

1994 ◽  
Vol 03 (01) ◽  
pp. 239-248 ◽  
Author(s):  
M.K. BHARDWAJ ◽  
I.A. RIZVI ◽  
A.K. CHAUBEY
Keyword(s):  
Excitation Function ◽  
Beam Energy ◽  
Gamma Ray ◽  
Computer Code ◽  
Reaction Yield ◽  
Activation Technique ◽  
Model Calculations ◽  
Equilibrium Fraction ◽  
Foil Activation ◽  
Stacked Foil Activation Technique

The excitation function of α-induced reactions on 121Sb and 123Sb has been measured. The α-beam energy ranges from 55.0±0.5 MeV to 21.9±1.2 MeV. In these experiments, the stacked foil activation technique was used. The reaction yield was measured by counting the gamma ray activity produced by the alpha-induced reactions. Results so obtained were compared with the calculations from the geometry-dependent hybrid (GDH) model. The assumption of initial exciton number n0=4 with n=2, p=2 and h=0 best satisfies the results measured in the present work. The model calculations were done using the ALICE/LIVERMORE-82 computer code. The pre-equilibrium fraction has also been calculated.

Bremsstrahlung linear polarization

1989 ◽  
Vol 67 (6) ◽  
pp. 545-561
Author(s):  
W. Del Bianco ◽  
M. Carignan
Keyword(s):  
Differential Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Linear Polarization ◽  
Differential Cross ◽  
Born Approximation ◽  
Gamma Ray ◽  
High Energy ◽  
Scattered Electron ◽  
Triple Differential Cross Section

The dependence of the bremsstrahlung perpendicular and parallel triple differential cross sections and the linear polarization on the angles and energies of the incident and scattered electron and of the emitted gamma-ray has been studied in the high-energy small-angle hypothesis. The expression used for the bremsstrahlung triple differential cross section is valid in the Born approximation and for an unscreened Coulomb potential of the nucleus.

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