Energy deposited on the first channel in lithium 6 chamber

The pulse amplitude spectrum was calculated about lithium 6 chamber, the result is:

the magnitude on the first channel is especially large, what induced this?
it seems the magnitude on the first channel is normal by Mcnp6, here is the result:

Dear @Newconcept_1979,

if you are using the DETECT scoring with zero minimum energy, then all events where no energy is deposited in the detector is still added to the first bin.

You can avoid this, by

  1. Setting the minimum energy to a marginal value, like 1e-12, or
  2. Set the detector region as a trigger as well in coincidence with itself.


@horvathd , thanks for your reply!