add limit for the thickness and radius

[subindev-d]

Is your feature request related to a problem? Please describe.
Once the #31 is merged , need to implement limits for the new parameteres tFermi and radius
Describe the solution you'd like
The minimum value for the tFermi should be > R * .915723
Maxmimum value of the radius should be < 2 * 2.2291e-5 * pow(A, 1.0 / 3.0) - 0.90676e-5