I've seen several discussions on the forum regarding neutron flux estimation using detectors and flux units. Excuse me, I still have a few questions (Note: I am using Serpent 2.1.24):

1) TOT_FLUX is the total flux integrated over the geometry and all energy groups. In the User's Manual, it is written that "All flux values are divided by volume" (page 86). I did the following test: I defined a detector for the flux estimation in all volumes, and I specified 1 energy group. Then, I did summation over all bins. If I don’t divide the obtained value by the total volume, I get the same value as TOT_FLUX. Otherwise, if I divide by the volume, the flux values are different. Do I misinterpret anything or there is an inaccuracy in the User's Manual?

The detectors are the following:

Code: Select all

```
ene 2 3 100 1E-11 20.0
det All1 de 2 du 0 dv 1.0e4
det All2 de 2 du 0
```

2) Could you please correct me, if my understanding of the flux unites in SERPENT is wrong?

- TOT_FLUX value is in [n/cm^2/s]

- The output from the flux detector after the division by volume also provides flux in [n/cm^2/s]

For example, the following detector provides flux [n/cm^2/s] as a function of energy [MeV] (flux spectrum in other words) for the whole reactor.

Code: Select all

```
ene 2 3 100 1E-11 20.0
det All de 2 du 0 dv 1.0e4
```

Thank you very much in advance for your response!

With best regards,

Sasha.