# Benchmark against MCNP and Tripoli4 unsatisfactory

**URL:** <https://openmc.discourse.group/t/benchmark-against-mcnp-and-tripoli4-unsatisfactory/3154>\
**Category:** Validation and Verification\
**Created:** [June 27, 2023, 12:55pm UTC](https://openmc.discourse.group/t/benchmark-against-mcnp-and-tripoli4-unsatisfactory/3154 "2023-06-27T12:55:51Z")\
**Posts on this page:** 1\
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**Author:** ![yrrepy](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/yrrepy/32/2365_2.png) [@yrrepy](https://openmc.discourse.group/u/yrrepy)\
**Post date:** [June 27, 2023, 9:18pm UTC](https://openmc.discourse.group/t/benchmark-against-mcnp-and-tripoli4-unsatisfactory/3154/4 "2023-06-27T21:18:17Z")

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Because OpenMC subdivides the energy. Most of the photon kerma energy is in the ‘electron’ bin.

> [@Photon heating](https://openmc.discourse.group/t/photon-heating/619/4):
>
> Yes, I do suggest taking the sum of photon+electron+positron. If the positron energy is negative, that means that too much energy was given to photons, so when you add them together it should balance out. In most cases I’ve looked at, the positron energy is not negative; I’m not sure if there is something about your particular case that causes that behavior. Best, Paul

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