# energy_low(keV)  energy_high(keV)  fractional_rms  fractional_rms_error
     0.300000          0.460000         0.0352395         0.0109030    
     0.460000          0.700000         0.0433989         0.0105743    
     0.700000           1.00000         0.0566982         0.0132613    
      1.00000           1.54000              -NaN              -NaN    
      1.54000           2.40000         0.0746790         0.0292675    
      2.40000           4.80000              -NaN              -NaN    
      4.80000           10.0000              -NaN              -NaN