wavel.	cross section	error limit

230	3.15e-18	2.0e-19
240	3.50e-18	1.3e-19
250	3.57e-18	1.5e-19
260	2.80e-18	7.0e-20
270	2.00e-18	1.3e-19
280	1.10e-18	2.1e-19