Two thermal neutron beams are injected from opposite directi

Two thermal neutron beams are injected from opposite directions into a thin sample of At a given point in the sample, the beam intensities are 10^12 neutrons/cm^2 sec from the left and 1 times 10^12 neutrons/cm^2,sec from the right, Compute: (a) the at this point,

Solution

Answer:

Neutron Flux

In 235U fission, one thermal neutron causes the 3 neutons after fission

So, the neutron flux = 3 x 10¹² + 3 x 2 x 10¹² = 9 x 10¹² neutrons/cm²

Neutron current density

J (along the direction of incidence) = 2 x 10¹² - 1 x 10¹² = 1 x 10¹²