Abstract

      In the present work, the stopping powers of alpha particle energies from near threshold energy to 10 MeV for light elements (₃⁷Li, ₅¹¹B, ₆¹³C, ₈¹⁸O, ₉¹⁹F, ₁₀²²Ne,  ₁₁²³Na, ₁₄³⁰Si) and medium elements (₂₁⁴⁵Sc, ₂₄⁵²Cr, ₂₆⁵⁷Fe, ₂₈⁶²Ni) have been calculated using the Zeigler formula.

      The cross-sections of the nuclear reactions ₃⁷Li(a,n)₅¹⁰B_{, 5}¹¹B(a,n)₇¹⁴N_{, 6}¹³C(a,n)₈¹⁶O_{, 8}¹⁸O(a,n)₁₀²¹Ne, ₉¹⁹F(a,n)₁₁²²Na_{, 10}²²Ne(a,n)₁₂²⁵Mg_{, 11}²³Na(a,n)₁₃²⁶Al_{, 14}³⁰Si(a,n)₁₆³³S_{, 21}⁴⁵Sc(a,n)₂₃⁴⁸V, ₂₄⁵²Cr(a,n)₂₆⁵⁵Fe, ₂₆⁵⁷Fe(a,n)₂₈⁶⁰Ni, ₂₈⁶²Ni(a,n)₃₀⁶⁵Zn have been calculated from those of the inverse nuclear reactions such as ₅¹⁰B(n,a)₃⁷Li, ₇¹⁴N(n,a)₅¹¹B, ₈¹⁶O(n,a)₆¹³C, ₁₀²¹Ne(n,a)₈¹⁸O, ₁₁²²Na(n,a)₉¹⁹F, ₁₂²⁵Mg(n,a)₁₀²²Ne, ₁₃²⁶Al(n,a)₁₁²³Na, ₁₆³³S(n,a)₁₄³⁰Si, ₂₃⁴⁸V(n,a)₂₁⁴⁵Sc, ₂₆⁵⁵Fe(n,a)₂₄⁵²Cr, ₂₈⁶⁰Ni(n,a)₂₆⁵⁷Fe, ₃₀⁶⁵Zn(n,a)₂₈⁶²Ni using the reciprocity theorem. The obtained results have been rearranged and interpolated for α-particle energies from near threshold up to (10 MeV) in steps of 0.050 MeV by using the MATLAB computer program in lab. System. The obtained data were used to calculate the weighted average of the cross-section in unit of (mb).

The obtained weighted average of the cross-sections (mb) were taken into consideration and used to calculate the neutron yields (n/10⁶α) of the above reactions as a function of α-particle energies in the lab. System.

      The kinetic energies (T_α) and the branching ratios of each α-emitters such as (²¹⁰Po, ²³⁴U, ²³⁵U, ²³⁸U, ²³⁸Pu, ²³⁹Pu and ²⁴¹Am) are taken into consideration to calculate the mean kinetic energy <T_α>.

      The polynomial expressions have been used to fit the calculated  neutron yields of the studied light and medium elements to determine the neutron yields  from the best fitting equations with minimum (CHISQ) at various α-particle energies in the lab. system.

   Empirical formulae for light elements of a set of reactions such as ⁷Li(α,n)¹⁰B, ¹¹B(α,n)¹⁴N and ¹⁹F(a,n)²²Na and for medium elements of a set of reactions such as ⁴⁵Sc(α,n)⁴⁸V, ⁵⁷Fe(α,n)⁶⁰Ni  and ⁶²Ni(α,n)⁶⁵Zn have been used to calculate the neutron yields (n/10⁶α) for each reactions as a function of α-particle energies in lab. system and the atomic number (Z) of the target nucleus.                                       

 posted:25-10-2017