plot "q8gain.dat" t "beamD=6.1mm"w errorbars points 1 5    
set grid
set xrange [0:1.6]
set yrange [0:1.5]
set title "beam distance=6.1mm space charge effect"
set xlabel "1stpulse charge(pc)"
set ylabel "ratio"
replot
save "bd6mm.gnu"
set term post landscape "Times-Roman" 36
set output "bd6mm.ps"
replot



5.3:4.5:3.0:2.2: