Accelerator, radiation and x-ray optics simulation framework

An Introduction to Ocelot

Ocelot is a multiphysics simulation toolkit designed for studying FEL and storage ring-based light sources. Ocelot is written in Python. Its central concept is the writing of python's scripts for simulations with the usage of Ocelot's modules and functions and the standard Python libraries.

Ocelot includes following main modules:

Ocelot extensively uses Python's NumPy (Numerical Python) and SciPy (Scientific Python) libraries, which enable efficient in-core numerical and scientific computation within Python and give you access to various mathematical and optimization techniques and algorithms. To produce high quality figures Python's matplotlib library is used.

It is an open source project and it is being developed by physicists from The European XFEL, DESY (Germany), NRC Kurchatov Institute (Russia).

We still have no documentation but you can find a lot of examples in /demos/ folder including this tutorial

Ocelot user profile

Ocelot is designed for researchers who want to have the flexibility that is given by high-level languages such as Matlab, Python (with Numpy and SciPy) or Mathematica. However if someone needs a GUI it can be developed using Python's libraries like a PyQtGraph or PyQt.


The tutorial includes 7 simple examples dediacted to beam dynamics and optics. However, you should have a basic understanding of Computer Programming terminologies. A basic understanding of Python language is a plus.

This tutorial requires the following packages:

Optional, but highly recommended for speeding up calculations

Orbit Correction module

The easiest way to get these is to download and install the (large) Anaconda software distribution.

Alternatively, you can download and install miniconda. The following command will install all required packages:

$ conda install numpy scipy matplotlib jupyter

Ocelot installation

Anaconda Cloud recommended

The easiest way to install OCELOT is to use Anaconda cloud. In that case use command:

 $ conda install -c ocelot-collab ocelot

Clone OCELOT from GitHub:

$ git clone

or download last release zip file. Now you can install OCELOT from the source:

$ python install

Another way is download ocelot from GitHub

  1. you have to download from GitHub zip file.
  2. Unzip to your working folder /your_working_dir/.
  3. Add ../your_working_dir/ocelot-master to PYTHONPATH

    • Windows 7: go to Control Panel -> System and Security -> System -> Advance System Settings -> Environment Variables. and in User variables add /your_working_dir/ocelot-master/ to PYTHONPATH. If variable PYTHONPATH does not exist, create it

    Variable name: PYTHONPATH

    Variable value: ../your_working_dir/ocelot-master/

    • Linux:
      $ export PYTHONPATH=/your_working_dir/ocelot-master:$PYTHONPATH

To launch "ipython notebook" or "jupyter notebook"

in command line run following commands:

$ ipython notebook


$ ipython notebook --notebook-dir="path_to_your_directory"


$ jupyter notebook --notebook-dir="path_to_your_directory"

OCELOT jupyter tutorials

You can download OCELOT jupyter tutorials (release v18.02) using GitHub link zip file.


Photon field simulation


Disclaimer: The OCELOT code comes with absolutely NO warranty. The authors of the OCELOT do not take any responsibility for any damage to equipments or personnel injury that may result from the use of the code.