eventio 0.3.0

Python read-only implementation of the EventIO file format

A Python (read-only) implementation of the EventIO data format invented by Konrad Bernloehr as used for example by the IACT extension for CORSIKA: https://www.ikp.kit.edu/corsika

Reading the data of the following Objects is currently supported:

Code	Description
1200	CORSIKA Run Header
1201	CORSIKA Telescope Positions
1202	CORSIKA Event Header
1203	CORSIKA Array Offsets
1204	CORSIKA Telescope Data
1205	IACT Photons
1209	CORSIKA Event End Block
1210	CORSIKA Run End Block
1211	CORSIKA Longitudinal Block
1212	CORSIKA Input Card

The following blocks are known, but reading their data is not (yet) implemented:

Code	Description
1206	IACT Layout
1207	IACT Trigger Time
1208	IACT PhotoElectrons

install with

pip install eventio

Open a file produced by the IACT CORSIKA extension

First Example

One may iterate over an instance of IACTFile class in order to retrieve events. Events have a small number of fields. The most important one is the photon_bunches field, which is dictionary mapping telescope ids to a simple structured np.array, containing the typical parameters Cherekov photons bunches in Corsika have, like:

• x, y coordinate in the observation plane (in cm)

• direction cosine cx, cy in x and y direction of the incident angle of the photon

• wavelength lambda of the photon (in nm)

• number of photons associated with this bunch

• the time since the first interaction (in ns, I believe)

• the production height of the photon bunch (called zem)

• a bool flag, whether the photon was scattered in the atmosphere

An event has the following attributes: * header: a dictionary containing the Corsika Event Header data * end_block: a numpy array containing the Corsika Event End data * time_offset, x_offset, y_offsett, the offset of the array

This prints the number of photons for the first telescope in every event:

import eventio

with eventio.IACTFile('data/telescope.dat') as f:
    for event in f:
        print(event.photon_buches[0]['photons'].sum())

Second Example

If you like to plot the origin of the Cherenkov photons of the first event in file data/telescope.dat for the first telescope, have a look into this example

It might look similar to this picture:

an example shower

Low level access

For more low level access to the items of an EventIO file (or to implement a higher level abstraction like IACTFile) one can use the EventIOFile class which gives access to the Objects and subitems in EventIO files.

This is how our test file looks like in the low level view:

In [1]: import eventio

In [2]: eventio.EventIOFile('eventio/resources/one_shower.dat')
Out[2]:
EventIOFile(path=eventio/resources/one_shower.dat, objects=[
  CorsikaRunHeader(first=0, length=1096)
  CorsikaInputCard(first=1112, length=448)
  CorsikaTelescopeDefinition(first=1576, length=20)
  CorsikaEventHeader(first=1612, length=1096)
  CorsikaArrayOffsets(first=2724, length=16)
  CorsikaTelescopeData(first=2756, length=6136, subitems=1)
  CorsikaEventEndBlock(first=8908, length=1096)
  CorsikaRunEndBlock(first=10020, length=16)
])

And this is how a sim_telarray file looks like (sim_telarray objects are not implemted yet):

In [3]: eventio.EventIOFile('gamma_test.simtel')
Out[3]:
EventIOFile(path=../../CTA/ctapipe/ctapipe-extra/datasets/gamma_test.simtel, objects=[
  UnknownObject[70](first=0, length=11960, subitems=131)
  UnknownObject[70](first=11976, length=1744732, subitems=21526)
  UnknownObject[70](first=1756724, length=838000, subitems=11186)
  UnknownObject[2000](first=2594740, length=1876)
    ...
  UnknownObject[2010](first=50007852, length=1782080, subitems=19)
  UnknownObject[2021](first=51789948, length=12)
  UnknownObject[2026](first=51789976, length=3536)
  UnknownObject[2010](first=51793528, length=1560656, subitems=9)
])