wavel.	cross section	error limit

200	1.70e-18	5.3e-19
207	2.07e-18	2.1e-19
220	2.38e-18	3.0e-19
230	2.35e-18	2.6e-19
240	2.13e-18	5.5e-19
250	2.05e-18	2.4e-19
260	1.57e-18	4.1e-19
270	6.50e-19