1 #class tools::histo::h1d
 2 #title nb steps of primary particle
 3 #dimension 1
 4 #axis fixed 100 0 300
 5 #annotation axis_x.title 
 6 #bin_number 102
 7 entries
 8 0
 9 0
10 0
11 3
12 50
13 351
14 1147
15 2314
16 2645
17 1979
18 1002
19 368
20 110
21 27
22 4
23 0