# About Crosssection libraries **URL:** \ **Category:** User Support\ **Created:** [June 9, 2021, 1:22pm UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241 "2021-06-09T13:22:22Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![Mashaba](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/mashaba/32/1328_2.png) [@Mashaba](https://openmc.discourse.group/u/Mashaba)\ **Post date:** [June 9, 2021, 1:22pm UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/1 "2021-06-09T13:22:22Z")
RuntimeError: Nuclear data library does not contain cross sections for c\_Graphite at temperatures that bound 294.0 K. I’ve been getting this error … whenever i use the command: graphite.add\_s\_alpha\_beta(‘c\_Graphite’) i have changed my cross section library to Jeff 3.3 but it still shows the same error…how can i solve this problem? ---
**Author:** ![Pranto](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/pranto/32/489_2.png) [@Pranto](https://openmc.discourse.group/u/Pranto)\ **Post date:** [June 9, 2021, 2:32pm UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/2 "2021-06-09T14:32:32Z")
Welcome to the forum @Mashaba Thermal scattering data for `Graphite` doesn’t come with the official [JEFF-3.3 library](https://www.oecd-nea.org/dbdata/jeff/jeff33/tsl.html). You can change your library to ENDF-7.1 or ENDF-8 which you can download from [official library](https://openmc.org/official-data-libraries/). ---
**Author:** ![Mashaba](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/mashaba/32/1328_2.png) [@Mashaba](https://openmc.discourse.group/u/Mashaba)\ **Post date:** [June 9, 2021, 3:59pm UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/3 "2021-06-09T15:59:06Z")
thank you so much! @Pranto i have tried both…it still shows the same error ---
**Author:** ![Pranto](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/pranto/32/489_2.png) [@Pranto](https://openmc.discourse.group/u/Pranto)\ **Post date:** [June 9, 2021, 4:36pm UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/4 "2021-06-09T16:36:00Z")
That’s strange! Ok, What is the output of ```bash grep -rw $OPENMC_CROSS_SECTIONS -e c_Graphite.h5 ``` command? ---
**Author:** ![Pranto](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/pranto/32/489_2.png) [@Pranto](https://openmc.discourse.group/u/Pranto)\ **Post date:** [June 9, 2021, 4:52pm UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/5 "2021-06-09T16:52:32Z")
> [@Mashaba](#): > > RuntimeError: Nuclear data library does not contain cross sections for c\_Graphite at temperatures that bound 294.0 K. FYI, TSL for `Graphite` is available at ```auto ['1000K', '1200K', '1600K', '2000K', '296K', '400K', '500K', '600K', '700K', '800K'] ``` temperature from both ENDF-7.1 and ENDF-8. ---
**Author:** ![Javier\_Gonzalez](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/javier_gonzalez/32/1095_2.png) [@Javier\_Gonzalez](https://openmc.discourse.group/u/Javier_Gonzalez)\ **Post date:** [June 9, 2021, 6:00pm UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/6 "2021-06-09T18:00:35Z")
Hi @Mashaba, if your graphite temperature is 294.0 K, for that temperature nuclear data doesn’t exist. In that case, you can add settings.temperature = {‘method’: ‘interpolation’} to your Settings to interpolate. More details [here](https://docs.openmc.org/en/stable/pythonapi/generated/openmc.Settings.html). ---
**Author:** ![Mashaba](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/mashaba/32/1328_2.png) [@Mashaba](https://openmc.discourse.group/u/Mashaba)\ **Post date:** [June 9, 2021, 11:57pm UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/7 "2021-06-09T23:57:13Z")
@Pranto this command shows syntax error ---
**Author:** ![Mashaba](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/mashaba/32/1328_2.png) [@Mashaba](https://openmc.discourse.group/u/Mashaba)\ **Post date:** [June 10, 2021, 12:03am UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/8 "2021-06-10T00:03:14Z")
i have done that as well. It still shows the same error ---
**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:** [June 10, 2021, 1:32am UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/9 "2021-06-10T01:32:11Z")
If you’re using temperature interpolation, you need data to be available at two temperatures that surround the actual temperature. In this case, your material is at 294 K but the lowest available temperature in the dataset is 296 K. I think your options are either to: 1. Change the temperature of the material to be slightly higher (296 or 297 K) which should have minimal impact on results, or 2. Don’t use temperature interpolation at all. The ‘nearest’ temperature method uses a tolerance of 10 K by default, so if the material is at 294 K it should work fine with the 296 K data. ---
**Author:** ![Mashaba](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/mashaba/32/1328_2.png) [@Mashaba](https://openmc.discourse.group/u/Mashaba)\ **Post date:** [June 10, 2021, 2:03am UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/10 "2021-06-10T02:03:14Z")
Apparently that problem is solved. I used the nearest option. Thank you so much! ## But i am now experiencing a runtime error given below…Is it because of the version i am using?(0.12.1) RuntimeError Traceback (most recent call last) in ----\> 1 openmc.run() ~/miniconda3/lib/python3.9/site-packages/openmc/executor.py in run(particles, threads, geometry\_debug, restart\_file, tracks, output, cwd, openmc\_exec, mpi\_args, event\_based) 225 args = mpi\_args + args 226 → 227 \_run(args, output, cwd) ~/miniconda3/lib/python3.9/site-packages/openmc/executor.py in \_run(args, output, cwd) 36 error\_msg = ’ '.join(error\_msg.split()) 37 —\> 38 raise RuntimeError(error\_msg) 39 40 RuntimeError: OpenMC aborted unexpectedly. ---
**Author:** ![Pranto](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/pranto/32/489_2.png) [@Pranto](https://openmc.discourse.group/u/Pranto)\ **Post date:** [June 10, 2021, 2:54am UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/11 "2021-06-10T02:54:10Z")
@Mashaba What did you see when you run `openmc` from the command line? ---
**Author:** ![Mashaba](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/mashaba/32/1328_2.png) [@Mashaba](https://openmc.discourse.group/u/Mashaba)\ **Post date:** [June 10, 2021, 2:58am UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/12 "2021-06-10T02:58:24Z")
i saw this after the openmc.run() command line ``` %%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%% ############### %%%%%%%%%%%%%%%%%%%%%%%% ################## %%%%%%%%%%%%%%%%%%%%%%% ################### %%%%%%%%%%%%%%%%%%%%%%% #################### %%%%%%%%%%%%%%%%%%%%%% ##################### %%%%%%%%%%%%%%%%%%%%% ###################### %%%%%%%%%%%%%%%%%%%% ####################### %%%%%%%%%%%%%%%%%% ####################### %%%%%%%%%%%%%%%%% ###################### %%%%%%%%%%%%%%%%% #################### %%%%%%%%%%%%%%%%% ################# %%%%%%%%%%%%%%%%% ############### %%%%%%%%%%%%%%%% ############ %%%%%%%%%%%%%%% ######## %%%%%%%%%%%%%% %%%%%%%%%%% | The OpenMC Monte Carlo Code Copyright | 2011-2021 MIT and OpenMC contributors License | https://docs.openmc.org/en/latest/license.html Version | 0.12.1 Git SHA1 | d49e6ccb837685e399efdef8b29e46cdc693ccec Date/Time | 2021-06-10 08:41:28 OpenMP Threads | 6 ``` Reading settings XML file… Reading cross sections XML file… Reading materials XML file… Reading geometry XML file… Reading U235 from /home/mashaba/Downloads/endfb80.tar(2)/endfb80\_hdf5/U235.h5 Reading U238 from /home/mashaba/Downloads/endfb80.tar(2)/endfb80\_hdf5/U238.h5 Reading C12 from /home/mashaba/Downloads/endfb80.tar(2)/endfb80\_hdf5/C12.h5 Reading O16 from /home/mashaba/Downloads/endfb80.tar(2)/endfb80\_hdf5/O16.h5 Reading C13 from /home/mashaba/Downloads/endfb80.tar(2)/endfb80\_hdf5/C13.h5 Reading Si28 from /home/mashaba/Downloads/endfb80.tar(2)/endfb80\_hdf5/Si28.h5 Reading Si29 from /home/mashaba/Downloads/endfb80.tar(2)/endfb80\_hdf5/Si29.h5 Reading Si30 from /home/mashaba/Downloads/endfb80.tar(2)/endfb80\_hdf5/Si30.h5 Reading He3 from /home/mashaba/Downloads/endfb80.tar(2)/endfb80\_hdf5/He3.h5 Reading He4 from /home/mashaba/Downloads/endfb80.tar(2)/endfb80\_hdf5/He4.h5 Reading c\_Graphite from /home/mashaba/Downloads/endfb80.tar(2)/endfb80\_hdf5/c\_Graphite.h5 Minimum neutron data temperature: 294.0 K Maximum neutron data temperature: 294.0 K Preparing distributed cell instances… Writing summary.h5 file… Maximum neutron transport energy: 20000000.0 eV for C13 Initializing source particles… ====================\> K EIGENVALUE SIMULATION \<==================== ---
**Author:** ![Mashaba](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/mashaba/32/1328_2.png) [@Mashaba](https://openmc.discourse.group/u/Mashaba)\ **Post date:** [June 10, 2021, 3:00am UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/13 "2021-06-10T03:00:57Z")
After showing ‘initializing source particles’ it says that openmc aborted unexpectedly @Pranto ---
**Author:** ![Pranto](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/pranto/32/489_2.png) [@Pranto](https://openmc.discourse.group/u/Pranto)\ **Post date:** [June 10, 2021, 3:15am UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/15 "2021-06-10T03:15:45Z")
@Mashaba Have you checked overlapping cell definitions? You can do this by running `openmc.run(geometry_debug=True)` ---
**Author:** ![Pranto](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/pranto/32/489_2.png) [@Pranto](https://openmc.discourse.group/u/Pranto)\ **Post date:** [June 10, 2021, 3:20am UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/16 "2021-06-10T03:20:24Z")
If you’re using temperature `nearest` method, you can set tolerance ```python settings_file.temperature = { 'method' :'nearest', 'tolerance' : 300.0 } ``` ---
**Author:** ![Mashaba](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/mashaba/32/1328_2.png) [@Mashaba](https://openmc.discourse.group/u/Mashaba)\ **Post date:** [June 10, 2021, 3:25am UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/17 "2021-06-10T03:25:17Z")
``` <=================== ``` Cell ID No. Overlap Checks 1 244530 2 2357696 3 3145491 4 3596587 5 7385881 There were 0 overlapping cells woaaahh! it is suddenly giving the outputs with INTERPOLATION COMMAND too!!!.. THANKS A TON! @Pranto ---
**Author:** ![Pranto](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/pranto/32/489_2.png) [@Pranto](https://openmc.discourse.group/u/Pranto)\ **Post date:** [June 10, 2021, 4:02am UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/18 "2021-06-10T04:02:40Z")
Great @Mashaba The output here means cell id and number of checks have been performed for each cell. You can adjust initial source particle to get a good coverage. ---
**Author:** ![Mashaba](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/mashaba/32/1328_2.png) [@Mashaba](https://openmc.discourse.group/u/Mashaba)\ **Post date:** [June 10, 2021, 4:06am UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/19 "2021-06-10T04:06:29Z")
and how should i do that…? im not sure if i understand that properly can u provide me a reference? @Pranto ---
**Author:** ![Pranto](https://yyz2.discourse-cdn.com/free1/user_avatar/openmc.discourse.group/pranto/32/489_2.png) [@Pranto](https://openmc.discourse.group/u/Pranto)\ **Post date:** [June 10, 2021, 4:38am UTC](https://openmc.discourse.group/t/about-crosssection-libraries/1241/20 "2021-06-10T04:38:24Z")
If you run openmc in `geometry-debugging `mode with fewer particles in the case of complex geometry where two surfaces are close to each other, you’ll see the number of checks quite low. In that case, you can adjust the source particle to get good coverage of each area of geometry. Don’t worry, you’re fine now, you have simple geometry.