Article

1998 ◽  
Vol 76 (10) ◽  
pp. 785-791
Author(s):  
N L Singh ◽  
D J Shah ◽  
H B Patel

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

1994 ◽  
Vol 03 (01) ◽  
pp. 239-248 ◽  
Author(s):  
M.K. BHARDWAJ ◽  
I.A. RIZVI ◽  
A.K. CHAUBEY

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.


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

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.


1994 ◽  
Vol 03 (03) ◽  
pp. 909-917
Author(s):  
A.V. MOHAN RAO ◽  
S.N. CHINTALAPUDI

Alpha particle-induced reactions on the target element vanadium were investigated from threshold up to 55 MeV using the foil-stack activation technique and the Ge(Li) gamma ray spectroscopy method. Excitation functions for the formation of reaction residues 54Mn, 52Mn, 51Cr, 48V, 47Sc, 46Sc were investigated. The experimental cross-sections were compared with the predictions based on updated hybrid model (ALICE/90) using n0=4 (4p0h) and level density parameter a=A/9. A general agreement was found for all the reactions of (α, xn) type. However, the model failed badly in all cases of (α, zαxn) type of reactions.


1989 ◽  
Vol 67 (11) ◽  
pp. 1091-1096 ◽  
Author(s):  
I. A. Rizvi ◽  
M. K. Bhardwaj ◽  
M. Afzal Ansari ◽  
A. K. Chaubey

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.


2000 ◽  
Vol 78 (2) ◽  
pp. 133-139 ◽  
Author(s):  
M K Bhardwaj ◽  
I A Rizvi ◽  
A K Chaubey

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


1993 ◽  
Vol 71 (3-4) ◽  
pp. 115-121 ◽  
Author(s):  
N. L. Singh ◽  
S. Agarwal ◽  
J. Rama Rao

The excitation functions of 51V [(α, xn), x = 1.3; (α, p3n); (α, α3n) (α, 2α)] and 59Co[(α, 2n); (α, αxn); x = 1, 2] reactions were measured up to 50 MeV by the stacked-foil activation technique and high-resolution Ce(Li)–HPGe spectroscopy method. Of these 51V(α, xnypzα) reactions were studied for the first time with better accuracy than earlier measurements, which were done with a poor resolution scintillation–Ge(Li) detectors some 20 years ago. In the case of 59Co, existing data show large discrepancies at low energy. Comparisons are presented with the prediction of hybrid and exciton models. While for the (α, xn) type of reactions, reasonably explainable pre-equilibrium contributions are found, there seem to be indications of direct inelastic scattering effects in the (α, αxn) type of reactions.


1996 ◽  
Vol 74 (9-10) ◽  
pp. 618-625 ◽  
Author(s):  
H. B. Patel ◽  
M. S. Gadkari ◽  
Bhruna Dave ◽  
N. L. Singh ◽  
S. Mukherjee

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.


2020 ◽  
Vol 239 ◽  
pp. 20009
Author(s):  
Mayeen Uddin Khandaker ◽  
Kotaro Nagatsu ◽  
Honoka Obata ◽  
Katsuyuki Minegishi ◽  
Ming-Rong Zhang ◽  
...  

The excitation function of the natCu(3He,x)65Zn nuclear reaction was measured from its threshold up to 53 MeV incident energy relative to the natTi(3He,x)48V monitor reaction by using the conventional stacked foil activation technique combined with HPGe γ-ray spectrometry. Our result is systematically higher than the IAEA recommendation, and more experimental works are desired especially above 25 MeV.


2020 ◽  
Vol 239 ◽  
pp. 17010
Author(s):  
Jaromir Mrazek ◽  
Eva Simeckova ◽  
Radomir Behal ◽  
Vadim Glagolev ◽  
František Vesely ◽  
...  

The proton, deuteron and alpha induced reactions are of a great interest for the assessment of induced radioactivity of accelerator components, targets and beam stoppers as well as isotope production for medicine and also to nuclear astrophysics. We present a new irradiation chamber for activation measurements, that forms a prolongation of long-term experimental activities using stacked-foil activation technique in NPI CAS, Řež. The chamber is based on an airlock system and is coupled to a pneumatic transfer system delivered by KIT Karlsruhe. This system is installed in GANIL/SPIRAL2-NFS and will be used for proton, deuteron and alpha particle activation measurements with long- and short-lived isotopes.


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