Grinnell College
Iowa State University
University of Utah

GrISU(tah) is a package of programs for simulating the development of amospheric showers and telescope response to atmospheric shower Cherenkov fronts. The package also contains a data analysis program to process the data generated by the detector model. Because the development of GrISU started in the context of the VERITAS experiment,  the package also contains tools for analysing and displaying VERITAS data as well as VERITAS specific configuration files.

The package is currently maintained by Charlie Duke (CD) and Stephan LeBohec (SLB). It is made up of 5 main programs of different origins:
  • The shower development simulation program used in GrISU is an older version of the kascade program taken from the ISUSim package. CD made numerous changes in the I/O and we now refer to it as kascade7. Glenn Sembroski (Purdue University) and Mary Kertzman (DePauw University) originally developed the kascade code.Glenn Sembroski and Mary Kertzman's most recent version compiles under Absoft-F77 and is thus VMS compatible.  It is the most developed and updated of all kascade version and  it is now included in this package.
  • The Cherenkov light emission and propagation program (cherenk) was developed at ISU by David Carter-Lewis and Gora Mohanty.  CD introduced the timing  and  implemented the control interface.
  • The detector simulation program (grisudet) was developed by CD and SLB. The program structure and some hardware models are inspired from SLB's earlier work on the CAT imaging telescope.
  • The analysis program (analysis) was developed by CD and SLB.
  • The final product analysis program (datareader) was originally developed by Pierre Colin and SLB but many corrections and additions were made by students at the department of Physics and Astronomy of the University of Utah (Michelle Hui, Gary Finnegan, Paul Nunez and others).
The program used to read VERITAS data was originally developed by John Quinn and Filip Pizlo. It has been modified by Michael Daniel to generate the GrISU specific format.

Distribution and Feedback:

Anyone is welcome to download the GrISU package to use it for any chosen purpose under the terms specified in the GNU General Public License. An explicit reference to the package and this distribution page should be given in publication of studies using the GrISU package. Comments and suggestions can be made by writing to the email distribution list (grisuATphysicsDOTedu ) in which you can be included on demand to receive information on new version releases and participate to GrISU related discussions and developments. Comments about the web page itself should be sent to .

Download and information:
Download the latest version (the name of the gziped tar file is the date of the version)
Modifications logbook and links to older versions
Manual pages for the latest version (We have to say that unfortunately we have failed keeping the manual up to date so if you see inconsistancies, do not be surprized and contact us for help.)
Plots, figures and animations produced with GrISU

Other programs:
Dirk Petry informed us that Grisu is the name of a dragon firefighter very popular among kids in Germany