do you get output during inactive cycles when you are using the "det" or "set csw" option? In both case that behavior is a bit unexpected and I can't seem to reproduce it with a simple input. For "csw" the check should be already at fission.c
Lines 348-350 of fission.c should be
Code: Select all
if ((RDB[DATA_CYCLE_IDX] > RDB[DATA_CRIT_SKIP]) &&
((ptr = (long)RDB[DATA_PTR_CRIT_SRC_DET]) > VALID_PTR))
WriteSourceFile(ptr, x, y, z, *u, *v, *w, E, 1.0, t0 + td, id);
Is your version of fission.c missing that check?
As for the detector option, collision detectors should not be scored before the beginning of the active cycles.
For the second part of your question, by 'initial conditions' do you mean "momentary neutron positions"? Setting up a detector
you can tally a certain fraction (defined by <frac>) of all of the virtual interactions sampled by Serpent~2. This provides a nice distribution of neutrons at random points of their life, i.e., not only at the fission source point. To use that distribution as an initial source for your transient simulation, you'll also have to set the time coordinate (last value) of each source point to zero and the weight of each source point (the second last value) to one. Edit: You can also set the source type to 2 in your source definition for automatic resetting of time and weight.