ACE/ULEIS Release Notes: The following are cumulative release notes for the ACE Ultra Low Energy Isotope Spectrometer (ULEIS) Level-2 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. ============================================================================= Time periods of significance to the Level-2 data are as follows: 1998-071 14:00 - 1998-073 15:45 No data due instrument commanding. 1998-111 07:30 - 1998-111 14:30 Instrument saturation. 1998-120 02:00 - 1998-120 06:00 Instrument saturation. 1998-124 01:00 - 1998-125 05:00 Instrument saturation. 1998-161 16:50 - 1998-167 16:35 No data due to possible C&DH reset problem. 1998-226 18:12 - 1998-226 19:21 No data due instrument commanding. 1998-227 14:18 - 1998-227 16:55 No data due instrument commanding. 1998-237 15:00 - 1998-240 00:00 Instrument saturation. 1998-238 01:00 - 1998-238 21:30 Instrument saturation. 1998-267 22:30 - 1998-268 04:00 Instrument saturation. 1998-317 15:00 - 1998-324 19:10 No data due to Leonid shower protection. 2000-047 13:15 - 2000-049 09:45 No data due to instrument commanding. 2000-116 15:00 - 2000-118 00:00 Instrument commanding. 2000-160 06:00 - 2000-161 00:00 Instrument saturation. 2000-175 12:00 - 2000-175 18:00 Instrument saturation. 2000-195 06:00 - 2000-198 00:00 Instrument saturation. 2001-090 00:00 - 2001-090 06:00 Instrument saturation. 2001-101 12:00 - 2001-101 16:00 Instrument saturation. 2001-118 00:00 - 2001-118 12:00 Instrument saturation. 2001-268 18:00 - 2001-270 00:00 Instrument saturation. 2001-282 17:25 - 2001-283 22:10 Instrument commanding. 2001-299 16:20 Automatic aperture door operation commenced (see entry below for October 26, 2001). 2001-359 06:00 - 2001-361 00:00 Possible instrument saturation. 2002-111 04:30 - 2002-113 00:00 Possible instrument saturation. 2003-301 10:20 - 2003-302 13:00 Approximate period in which the instrument had significant dead time due to high count rates. During this time, the dead time varied, with a maximum value of about 83% during the most intense portions of the event. 2003-306 18:00 - 2003-308 06:00 Possible instrument saturation. ============================================================================= February 22, 1999: Release of DOY 50 of 1998 -- DOY 8 of 1999, Version 1 of ULEIS Level-2 data. Each data file contains documentation of time tagged ion fluxes measurements and statistical flux uncertainties. Data are hourly averages of the flux measurements. The datafiles are processed based on daily files of Level-1 data. Bad or missing data is filled with -999.9, except at beginning or end of day when data is not supplied. Time tags are good to better than 128 seconds and mark the beginning of the data averaging interval. Alignment of sensors is such that a cone, angled 60 degrees down from the spacecraft +Z axis (oriented to be within 20 degree of the sun), completes a sweeps of a 20 degree-wide arc with each spin of the spacecraft. ----------------------------------------------------------------------------- May 18, 1999: Release of DOY 36 -- 116 of 1999, Version 1 of ULEIS Level-2 data. Formats for data files are the same as before. ----------------------------------------------------------------------------- September 2, 1999: Release of DOY 117 -- 143 of 1999, Version 1 of ULEIS Level-2 data. Formats for data files are the same as before. ------------------------------------------------------------------------------ September 24, 1999: Release of DOY 144 -- 251 of 1999, Version 1 of ULEIS Level-2 data. Formats for data files are the same as before. ------------------------------------------------------------------------------ September 27, 1999: Release of DOY 9 -- 35 of 1999, Version 1 of ULEIS Level-2 data. Formats for data files are the same as before. ------------------------------------------------------------------------------ December 3, 1999: Release of DOY 252 -- 305 of 1999, Version 1 of ULEIS Level-2 data. Formats for data files are the same as before. ------------------------------------------------------------------------------ February 17, 2000: Release of this data interval brings ULEIS Level-2 data release to DOY 21 of 2000. Formats for data files are the same as before. ------------------------------------------------------------------------------- March 2, 2000: Release of this data interval brings ULEIS Level-2 data release to DOY 48 of 2000. Formats for data files are the same as before. ------------------------------------------------------------------------------- March 30, 2000: Release of this data interval brings ULEIS Level-2 data release to DOY 76 of 2000. Formats for data files are the same as before. ------------------------------------------------------------------------------- October 26, 2001: Automatic door operation commenced on Oct 26 (DOY 299), 2001, and greatly reduces the incidence of saturation and loss of MCP gain during intense events. When the door moves to change the size of the entrance aperture of the instrument, the door location is telemetered in the instrument housekeeping data. Existing software automatically adjusts the instrument geometry factor for such periods, and so the ULEIS Level 2 fluxes at the ASC need no correction for door motion. ------------------------------------------------------------------------------- November 30, 2003: New release of data, from start of mission to date, that includes updated instrument calibration efficiency, release 7. This was done to account for changing MCP gains and was based on cross calibrations with data from other instruments on ACE and Wind. MCP efficiency change varies over time through-out the mission and is species dependent. The latest release represents the current best knowledge from the PI team on the instrument efficiency change. Formats for data files are the same as before. -------------------------------------------------------------------------------