| quotient of dN by da and by dt, where dN is the increment of the number of particles incident on a cross-sectional area da in the time interval dt |
N0 = d2N/da dt
Note 1 to entry: Generally the term neutron (or other particle) flux is used.
Note 2 to entry: This quantity is expressed in reciprocal seconds per unit area (m−2 s−1 or cm−2 s−1).
Note 3 to entry: This entry was numbered 393-14-27 in IEC 60050-393:2003.