To install iXAFS, drag the application into your Applications folder.  iXAFS 
contains a complete set of the Horae and IFEFFIT applications.

iXAFS understands .prj and .apj files, so you can now double click on them or 
drag them onto the iXAFS icon in the dock.  iXAFS will automatically launch 
Artemis to open .apj files.  If you click on an Athena .prj file, iXAFS will 
load its location.  You may then click on the Athena or Artemis icon to open 
the file. You can have multiple instances of Athena and Artemis running at 
the same time.  Additionally, you may select a directory in which Athena or 
Artemis should be run.

iXAFS is a universal binary that should work on OS X 10.4 and greater systems. 
Apple's X11 for Mac OS X is required.