# energy_low(keV)  energy_high(keV)  fractional_rms  fractional_rms_error
     0.300000          0.460000              -NaN              -NaN    
     0.460000          0.700000         0.0234637         0.0246868    
     0.700000           1.00000         0.0672565         0.0167508    
      1.00000           1.54000         0.0334494         0.0391629    
      1.54000           2.40000              -NaN              -NaN    
      2.40000           4.80000          0.119481         0.0388917    
      4.80000           10.0000         0.0615029         0.0475658