SGP/RL/C1 - Invalid mode 0 data

On 20081112 the filter wheel for the wide field-of-view (WFOV) channel was incorrectly 
rotated. The net effect was that we were recording neutral density filter data when we 
should have been collecting data with the channels completely blocked (mode 0 data). As a 
result, the WFOV mode 0 data contains contributions from the pulse return and the solar 
background that should not be present. The mode 0 data is used in the rlprof_merge VAP to 
remove the electronic background level from the analog signal. After the problem was 
identified the filter wheel was set back to its proper rotation on 20090112.
A work-around has been implemented in the rlprof_merge VAP to handle the lack of valid 
mode 0 during the affected period. The work-around involves computing the electronic 
background from pre-pulse data during nighttime periods only. With this technique we are not 
able to estimate the range-dependence of the electronic backgound, as we did before. 
However, this range dependence is typically quite weak, and so the impact on the rlprof_merge 
output is expected to be minimal.

The WFOV mode 0 data contains contributions from the pulse return and the solar 

background during the affected period. If one is trying to estimate the electronic background 
level for the raw analog data it is best to use the pre-pulse (gates 0 to ~380) data 
during nighttime periods.

• water_counts_low_glue_coef_slope
• electronic_background_elastic_analog_low
• elastic_counts_low_glue_coef_slope
• electronic_background_nitrogen_analog_low
• water_counts_low
• nitrogen_counts_low_glue_coef_slope
• electronic_background_water_analog_low
• elastic_counts_low
• elastic_counts_low_glue_coef_offset
• nitrogen_counts_low_glue_coef_offset
• water_counts_low_glue_coef_offset
• nitrogen_counts_low

• water_counts_low
• water_analog_low
• nitrogen_analog_low
• elastic_counts_low
• elastic_analog_low
• nitrogen_counts_low