This widget is used to enter  information relative to the frequency at which probes (in 3D)
have to be written in the probes file
(having the extension ".his".)
Warning : 
Make sure  the data entered in this field are coherent with the option taken, ie either an integer, or 
a real (in s) or a list of instant (in s).
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 SYRTHES version   : VERSION_SYRTHES
 Name help file  : Le2_3D_Op.html
 I. Rupp, C. Peniguel  -  may 2014
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