LET Behind Level 1 sectored species/energy-bin masks.
The masks files define which species/energy combinations are not reliable.
For each row:
	The timestamp in column 1 is the END of the period
	for which the masks file in column 2 applies.
BEGIN
2007-03-29T15:46:32.500	LET_Level1_sectored_masks_behind_000.txt
2010-08-02T06:41:00.000	LET_Level1_sectored_masks_behind_001.txt
2010-08-02T14:44:00.000 LET_Level1_sectored_masks_behind_002.txt
2010-08-03T04:29:00.000 LET_Level1_sectored_masks_behind_001.txt
2010-08-03T09:07:00.000 LET_Level1_sectored_masks_behind_002.txt
2010-11-22T17:01:07.000	LET_Level1_sectored_masks_behind_001.txt
2011-01-09T00:00:00.000	LET_Level1_sectored_masks_behind_003.txt
2011-01-12T16:06:14.250	LET_Level1_sectored_masks_behind_bad.txt
2011-03-08T03:46:00.000	LET_Level1_sectored_masks_behind_003.txt
2011-03-08T09:11:00.000	LET_Level1_sectored_masks_behind_d12.txt
2011-03-08T14:58:00.000	LET_Level1_sectored_masks_behind_003.txt
2011-03-08T17:48:00.000	LET_Level1_sectored_masks_behind_d12.txt
2011-03-31T23:33:00.000	LET_Level1_sectored_masks_behind_003.txt
2011-04-01T00:27:00.000	LET_Level1_sectored_masks_behind_d12.txt
2011-04-01T01:25:00.000	LET_Level1_sectored_masks_behind_003.txt
2011-04-01T02:21:00.000	LET_Level1_sectored_masks_behind_d12.txt
2011-05-31T00:20:00.000 LET_Level1_sectored_masks_behind_003.txt
2011-06-09T19:16:19.000	LET_Level1_sectored_masks_behind_bad.txt
2011-06-30T17:23:39.000	LET_Level1_sectored_masks_behind_ori.txt
2011-09-22T13:29:00.000	LET_Level1_sectored_masks_behind_003.txt
2011-09-23T03:30:00.000	LET_Level1_sectored_masks_behind_d12.txt
2011-09-24T10:48:00.000	LET_Level1_sectored_masks_behind_d03.txt
2011-09-26T06:59:00.000	LET_Level1_sectored_masks_behind_d12.txt
2011-10-03T19:47:00.000	LET_Level1_sectored_masks_behind_003.txt
2011-10-04T01:49:00.000	LET_Level1_sectored_masks_behind_d12.txt
2037-01-01T00:00:00.000	LET_Level1_sectored_masks_behind_003.txt
ENDENDENDENDENDENDENDEN	ENDENDENDENDENDENDENDENDENDENDEN