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.

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

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.

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

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.

Article

1998 ◽  
Vol 76 (10) ◽  
pp. 785-791
Author(s):  
N L Singh ◽  
D J Shah ◽  
H B Patel
Keyword(s):  
Hybrid Model ◽  
Alpha Particle ◽  
Gamma Ray ◽  
Experimental Results ◽  
Particle State ◽  
Activation Technique ◽  
Natural Iron ◽  
Foil Activation ◽  
Stacked Foil Activation Technique

The stacked-foil activation technique and HPGe gamma-ray spectroscopy were used for the investigation of alpha-particle-induced reactions on natural iron up to 50 MeV. Excitation functions for the production of reaction residues 57Ni, 56Ni, 58Co, 57Co, and 56Co from alpha-particle-induced reactions on 56Fe were measured with a view to improve the quality of earlier measurements. The experimental results were compared with calculations considering equilibrium as well as preequilibrium reactions according to hybrid model of Blann (ALICE/90). It was found that the initial exciton configuration n0= 4(2p + 2n + 0h ) i.e., pure particle state appears to give a good fit to the experimental data.PACS No.: 25.60

Preequilibrium emission of multiparticles in α-induced reactions with 55Mn nucleus

1989 ◽  
Vol 67 (11) ◽  
pp. 1091-1096 ◽  
Author(s):  
I. A. Rizvi ◽  
M. K. Bhardwaj ◽  
M. Afzal Ansari ◽  
A. K. Chaubey
Keyword(s):  
Experimental Data ◽  
Hybrid Model ◽  
Spectroscopy Method ◽  
Activation Technique ◽  
Target Element ◽  
Geometry Dependent Hybrid Model ◽  
Foil Activation ◽  
Γ Ray ◽  
Stacked Foil Activation Technique ◽  
First Time

α-induced reactions on the target element Mn were investigated from 7 to 60 MeV, using the stacked-foil activation technique and the Ge(Li) γ-ray spectroscopy method. Six excitation functions for the reaction residues 58Co, 57Co, 56Co, 55Co, 54Mn, and 52gMn were measured, of which 55Mn (α,α3n) 52gMn was measured for the first time. The experimental data were compared with calculations considering equilibrium as well as preequilibrium reactions according to the geometry-dependent hybrid model of Blann (see Phys. Rev. Lett. 27, 337 (1971); 27, 700E (1971); 27, 1550E (1971)). The initial exciton number, n0 = 4, with different configurations was tested. It was found that the configuration (2n + 2p + oh) appears to give a good fit to the experimental data.

Shell and odd-even effects on alpha-particle energy spectra from the (p,α) reaction on nuclei around neutron number 50

1987 ◽  
Vol 35 (2) ◽  
pp. 467-478 ◽  
Author(s):  
I. Kumabe ◽  
Y. Mito ◽  
M. Hyakutake ◽  
N. Koori ◽  
H. Sakai ◽  
...  
Keyword(s):  
Alpha Particle ◽  
Neutron Number ◽  
Particle Energy ◽  
Energy Spectra ◽  
Alpha Particle Energy
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