d_d_fusion_t Function

function d_d_fusion_t(eb) result(sigma)
    !+Calculates total cross section at a given Deuterium energy, `eb`,
    !+for the Tritium branch of Deuterium-Deutrium nuclear reactions
    !+
    !+###Equation
    !+$$ D + D \rightarrow T(1.01 MeV) + p(3.02 MeV) (50%)$$
    !+
    !+###References
    !+* Equations 8-9
    !+* Table IV in Ref. 7 [[atomic_tables(module)]]
    real(Float64), intent(in) :: eb
        !+ Deuterium energy [keV]
    real(Float64)             :: sigma
        !+ Cross Section [\(cm^2\)]

    real(Float64), dimension(5), parameter :: A = [ 5.5576d4,  2.1054d2,  &
                                                   -3.2638d-2, 1.4987d-6, &
                                                    1.8181d-10 ]
    real(Float64), dimension(4), parameter :: B = [0.d0,0.d0,0.d0,0.d0]
    real(Float64), parameter :: Bg = 31.3970
    real(Float64) :: S, E

    E = min(max(eb,0.5),5000.0)

    S = (A(1) + E*(A(2) + E*(A(3) + E*(A(4) + E*A(5))))) / &
        (1    + E*(B(1) + E*(B(2) + E*(B(3) + E*B(4)))))

    sigma = (1.0d-27)*(S/(E*exp(Bg/sqrt(E))))

end function d_d_fusion_t