 Usmin:	minimal supply voltage
 Usimax:	maximal ionization
 Us:	typical maintaning
 Icmin:	minimal cathode current
 Icminp:	minimal pulse cathode current
 Ic:	typical cathode current
 Icp:	typical pulse cathode current
 Icmax:	maximal cathode curren
 Icmaxp:	maximal pulse cathode current
 Symh.:	symbol height
