The Go4 Project page

New release: Go4 Version 6.3.0 (January 11th, 2024):

Support of Qt6; cmake build system (optional)

ROOT 6 with Qt5 web canvas for Linux, MacOS, and Windows 11

Go4  within docker container for all platforms

HTTP Server and web browser GUI

Python scripting in analysis and GUI

Optional HDF5 data format for event I/O


  •  Introduction (pdf )
  • Reference  (pdf )
  • Sourcecode browser (doxygen)  (html)


Enable Go4 environment at GSI linux:

For,, or

. /cvmfs/   

     (enables most recent Go4 Version)

. /cvmfs/ <versiontag>

     (enables version by number, e.g. 501-02)

. /cvmfs/ -h 

    (shows list of installed Go4 versions)


What is Go4?

The object-oriented system Go4 (GSI Object Oriented On-line Off-line system)  is based on ROOT (R. Brun et al.) with the specific requirements of the low and medium energy nuclear and atomic physics experiments implemented as extensions.

Go4separates analysis and GUI in two tasks which could run on different nodes. Communication is done through threads and sockets. The GUI is built with the Qt widget library using the Qt designer. Qt and ROOT are interfaced by QtROOT. Full ROOT functionality including menus and graphics is available without modifications. The Go4 analysis framework provides the syntax to organize the analysis in steps which can be controlled from the GUI. Each step has its own IO and processing classes. 
The Go4 event classes can be used to construct at runtime complex (composite) events which are stored by Go4 in trees and branches without explicit programming. 
The Go4 GUI includes a browser and tree viewer which can be used without analysis to process standard ROOT files. The tree viewer resolves arbitrary hierarchy levels of composite event trees.


Go4  has been developed on Linux  and was tested e.g. in the following environments:

OpenSUSE Leap 15, OpenSuSe Tumbleweed, Debian 7/8/9,  Ubuntu,...
with compilers: gcc  4.x.x,..., gcc 10.2.x
It should be portable to other UNIX platforms supported by ROOT.

Since June 2015: Go4 v5 with full control via HTTP server (Go4 GUI or web browser)

Since October 2019: Go4 v6 with ROOT6 /Qt5 webcanvas without X11 for Linux, MacOS, Windows

New since May 2021: Support of Qt6; cmake build system; docker container with SuSe Tumbleweed