| Description: | This instrument experienced general degradation over a period of more than a year. Please
see D120229.3 (DQPR-2693) and D120229.4 (DQPR-2763) for more information.
The 415nm channel was noisy. The noise wasn't extreme, so initially at least, the mentor
would not expect much impact in using the 415 data. However, toward the end of the
period covered by this DQR, we start seeing a general degradation of this instrument. On
20110720, after a calibration, channel 615 is dead. On 20111101 the open channel stops
functioning.
This instrument is calibrated every three months. The past couple/few calibrations showed
a steady decline in the sensitivity of 415. The declining sensitivity should be
generally accounted for by each new calibration, but as time moved one, one should become less
and less confident in those (415) data.
In general, the mentor would suggest using 20110720 as a cut-off date for reliable data
(all channels). Caution is given for all channels as the instrument is failing, though the
channels not specifically mentioned may be OK. |