SIT Release Notes: The following are cumulative release notes for the STEREO/IMPACT Suprathermal Ion Telescope (SIT) Level-1 datasets. As new datasets are released or old datasets are processed, this file will be extended. The assessment of data quality, such as for instrument saturations, represents the best current knowledge and may be retroactively updated in future releases. General notes and caveats regarding all SIT data are in another file (sit_caveats) that should consulted first. ============================================================================= SIT-A first operational data begins Jan 1, 2007 ============================================================================= SIT-B first operational data begins Jan 27, 2007 ============================================================================= posted 5/15/2009: 2009-132 22:59 (May 12) - 2009-136 02:40 (May 16) SIT-B out of calibration due to S/C reset ============================================================================= posted 8/10/2009: 2009-216 09:35 (Aug 4) - 2009-218 12:30 (Aug 6) SIT-A out of calibration due to S/C reset ============================================================================= posted 5/27/2010: 2010-144 12:27 (May 24) - 2010-146 03:35 (May 26) SIT-B data gap due to lack of DSN coverage; some other smaller gaps in May 2010 for same reason ============================================================================= posted 1/14/2011: 2011-008 21:25 (Jan 8) - 2011-013 19:11 (Jan 13) SIT-B out of calibration due to IMPACT power off ============================================================================= posted 4/20/2011: 2011-110 14:00 (April 20) -- SIT-A revised lookup tables improve accuracy of intensity boxes above ~1 MeV/nucleon; starting on day 111.0, onboard ROM boxes are used to calculate SIT-A intensities, with improved statistics in intense periods ============================================================================= posted 5/10/2011: 2011-125 17:04 (May 5) -- SIT-B revised lookup tables improve accuracy of track widths for rate boxes; starting on day 127.0, onboard ROM boxes are used to calculate SIT-B intensities, with improved statistics in intense periods ============================================================================= posted 7/12/2011: ROM box correction factors used to correct for coarseness in on-board matrix binning; applied to SIT-A starting 2011/110 and SIT-B 2011/125 (not used for earlier data). Errors affecting pulse-height analysis intensity calculation during some periods corrected. To be sure up to date intensities are used, users should replace all earlier files with files generated on or after July 11, 2011 ============================================================================= posted 9/23/2011: 2011-262-15:40 (Sept 19) to 2011-265-19:53 (Sept 22)-- SIT-A out of calibration due to IMPACT power off ============================================================================= posted 11/21/2012: 2012-205.0 (July 23) to 2012-207.0 (July 26) -- SIT-A out of calibration due to high intensities ============================================================================= posted 7/16/2014: 2014-187.71 (July 6) to 2014-195.65 (July 14) -- SIT-A out of calibration due to turn-off and HV ramp up for side lobe testing ============================================================================= posted 8/12/2014: The three lowest energy Fe energy bins for SIT-A and SIT-B removed due to uncertainties in resolution and calibration from ASCII data files posted at IMPACT/SEP web site (http://www.srl.caltech.edu/STEREO/Public/SIT_public.html). Fe files regenerated with lowest energy bin starting at 0.080 MeV/nuc. Users should replace all earlier Fe files with files generated on or after Aug 11, 2014. Other elements (H, 4He, O) not affected, and Fe energy bins starting at 0.080 MeV/nuc and higher not affected; however, format of the Fe files is changed since the three columns with the lowest energy bins have been removed. ============================================================================= posted 6/23/2015: 2012-149 00:00 (May 28) - 2012-149 12:00 (May 28) SIT-A out of calibration due high intensity levels saturating MCP response ============================================================================= posted 6/23/2015: 2012-205 05:00 (Jul 23) - 2012-206 06:00 (Jul 24) SIT-A out of calibration due high intensity levels saturating MCP response ============================================================================= posted 6/23/2015: 2013-234 01:00 (Aug 22) - 2012-235 02:00 (Aug 23) SIT-A out of calibration due high intensity levels saturating MCP response ============================================================================= posted 6/23/2015: 2014-244 00:00 (Sep 1) - 2014-246 02:00 (Sep 3) SIT-B out of calibration due high intensity levels saturating MCP response ============================================================================= posted 7/16/2015: 2015-79.66 (Mar 20) to 2015-190.80 (July 9) -- SIT-A off off for solar conjunction ============================================================================= posted 7/21/2015: 2015-190.80 (July 9) to ~2023 THIS POST FROM THE SEP INSTRUMENT SUITE WEB PAGE APPLIES TO SIT: Change in SEP Instrument Suite Viewing Directions: After solar conjunction, the two STEREO spacecraft have been rolled 180 degrees about the spacecraft-Sun line in order to allow the high gain antenna to remain pointing at Earth. Consequently, the nominal pointing directions of the SEP suite of instruments are now different. This will remain the case until the spacecraft pass by Earth again in 2023. ============================================================================= posted 8/27/2015: 2015-190.80 (July 9) to 2015-238.0 (August 26) (inclusive) SIT-A matrix rates out of calibration due to lookup table load problem during post-conjunction weak uplink period; obsolete tables in use; He intensity is roughly a factor of 5 low. ============================================================================= posted 8/27/2015: 2014-268 00:00 (Sep 25) - 2014-272 00:00 (Sep 29) SIT-B out of calibration due high intensity levels saturating MCP response ============================================================================= posted 9/1/2015: all ascii files of SIT 1-day, 1-hour, 10-min, and 1-min averages have been recomputed using improved SIT-A and -B calibrations obtained from comparison with LET spectra from a large set of SEP events. The changes are not large, but to be up to date, users should download the new set. The changes are incorporated into all files generated Aug. 30, 2015 or later. ============================================================================= posted 12/22/2015: all SIT multipanel plots for the solar conjunction period 2014/230 through 2015-319 have been recomputed using the instrument beacon data instead of the usual science data (see SIT description document). In terms of data packets, for SIT this corresponds to using the APID 624 packets (beacon) instead of the APID 605 packets (rates) since coverage for APID 605 was very low, while coverage for the APID 624 packet was nearly complete. However, the beacon packets carry a separate set of rates which are not identical to the APID 605 rates. The differences are: 1) the beacon rates cover the energy interval 120-360 keV/nuc, while the APID 605 rates used for the plots use a smaller interval 160-223 keV/nuc. 2) the beacon rates combine C, N, & O, while the APID 605 rate has O separate To maintain the comparability of the SIT multipanel plots for this period compared to others, the APID 605 and 624 rates were compared over the period 2014/65-100, and scaling factors derived that improve the match between the two sets of rates. The scaling factors applied were: a) beacon 120-360 keV/nuc He rate multiplied by 1.8 to approximate He 160-223 keV/n b) beacon 120-360 keV/nuc CNO rate multiplied by 1.2 to approximate O 160-223 keV/n c) beacon 120-360 keV/nuc Fe rate multiplied by 1.75 to approximate Fe 160-223 keV/n These factors are used for the posted multipanel plots ONLY, and are not used for the listings of SIT beacon data which also contain additional energy bands. ============================================================================= posted 11/13/2018: SIT-A matrix box calculations showed errors following the reset and table loads following the Sept 23, 2018 turn off due to a single event upset in the SEP data system. SIT-A matrix rates should not be used after Sept 23, 2018. Plots for posting on the web, and ascii files were switched over to intensities calculated with PHA data. =============================================================================