# Cylindrical source specification **URL:** \ **Category:** User Support\ **Created:** [July 8, 2019, 7:33pm UTC](https://openmc.discourse.group/t/cylindrical-source-specification/456 "2019-07-08T19:33:09Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Vedha](https://avatars.discourse-cdn.com/v4/letter/v/6bbea6/32.png) [@Vedha](https://openmc.discourse.group/u/Vedha)\ **Post date:** [July 8, 2019, 7:33pm UTC](https://openmc.discourse.group/t/cylindrical-source-specification/456/1 "2019-07-08T19:33:09Z")
Hi fellow users! Is there a way to specify cylindrical distribution of source sites in a fixed source problem? Thanks, Vedha ---
**Author:** ![paulromano](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/paulromano/32/486_2.png) [@paulromano](https://openmc.discourse.group/u/paulromano)\ **Post date:** [July 8, 2019, 8:53pm UTC](https://openmc.discourse.group/t/cylindrical-source-specification/456/2 "2019-07-08T20:53:56Z")
Hi Vedha, At the moment, there is no good way to specifying a cylindrical distribution of source sites using the preexisting classes. However, you could manually sample source sites in a cylinder yourself and then use a source file to achieve almost the same thing. If you’re interested in implementing a cylindrical source and submitting a pull request to the code, let us know and we can give some advice on where to start. Best regards, Paul ---
**Author:** ![Shimwell](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/shimwell/32/3876_2.png) [@Shimwell](https://openmc.discourse.group/u/Shimwell)\ **Post date:** [July 8, 2019, 9:30pm UTC](https://openmc.discourse.group/t/cylindrical-source-specification/456/3 "2019-07-08T21:30:02Z")
Another option is to use the Dlopen source [https://github.com/openmc-dev/openmc/pull/1257](https://github.com/openmc-dev/openmc/pull/1257) Best Jon