# Negative photon heating

**URL:** <https://openmc.discourse.group/t/negative-photon-heating/5485>\
**Category:** User Support\
**Created:** [May 7, 2025, 8:16am UTC](https://openmc.discourse.group/t/negative-photon-heating/5485 "2025-05-07T08:16:24Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![www.ebba.com](https://avatars.discourse-cdn.com/v4/letter/w/b77776/32.png) [@www.ebba.com](https://openmc.discourse.group/u/www.ebba.com)\
**Post date:** [May 7, 2025, 8:16am UTC](https://openmc.discourse.group/t/negative-photon-heating/5485/1 "2025-05-07T08:16:24Z")

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Hi!

I am looking at photon dose in a volume. The volume is separated from the source by a shield. I use the heating score over the volume cell and combine it with the particle filter for photons. I then run the problem for increasing shield thicknesses. The problem is that I get negative heating scores. Does anyone have a clue as to what I am doing wrong here?

 ![photon_heating](https://global.discourse-cdn.com/free1/uploads/openmc/original/2X/2/281e46920dc237a0ffe052edae413eeefcc83f25.png)

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**Author:** ![magnoxemo](https://avatars.discourse-cdn.com/v4/letter/m/5f8ce5/32.png) [@magnoxemo](https://openmc.discourse.group/u/magnoxemo)\
**Post date:** [May 7, 2025, 7:55pm UTC](https://openmc.discourse.group/t/negative-photon-heating/5485/2 "2025-05-07T19:55:30Z")

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Hi [www.ebba.com](http://www.ebba.com),

It would be more helpful for us if we could take a look at your script.