ACE/SEPICA Release Notes: Note: add newer notes to the top of this file 02 Feb 2006 Add Nitrogen data 24 March 2001 Version 6 -------------------------------------------------------------- < ver4 Level2 files produced prior to version 4 used SEPICA's matrix and sectored rates alone. The problem with this, is that it cannot take into account results of trails moving out of the box definitions in the dpu. ver4 The first version of the level2 files produced using the more advances pha/basic rate normalization method. The software producing these files could not reliably track large scale pressure changes, and it was possible for trail contamination to occur. ver5 Version 5 takes into account changes in pressure, and reliably keeps the proper trails in the proper boxes, but a bug introduced caused boxes He5, He6, He7, and He8 to give improper flux readings. ver6 Virtually identical to ver5 except for the removal of the aforementioned bug. 5 October 2000 Version 4 -------------------------------------------------------------- He rates: Two He rates have special significance because they include the ions from the internal Am241 calibration source in SEPICA. They are: He4cal and He Cal Alpha check (HeCAck). The difference between them is that HeCAck much more closely bounds the alpha particle peak. On quiet days, alphas from the Am241 source dominate the instrument counting rate. Excluding the He4cal rate from a spectrum substantially eliminates contamination by the calibration alphas. Alternatively, the external He rate in He4cal may be calculated by subtracting an average value of He4cal for quiet days. He8 spans He3, He4cal and He5 to provide a He flux at a mean energy of 1.4 MeV/nuc. He8 includes the calibration alpha rate. Heavy ion rates in the solid state detector high gain mode: When the low gain solid state detectors are in the high gain mode, the maximum measurable energy decreases. This enhances detection of He at the expense of high energy heavy ions. The following rates are available in this ssd high gain mode: Fe1 Mg1 Ne1 O1, O2 ClowE, C1, C2 He1, He2, He3, He4cal, He5, He6, He8, HeCAck H1, H2, H3 Periods when the instrument was in high-gain mode are 2000-070 to 2000-318 "LowE" rates: The rates with the "lowE" designation should always be used with caution. These rates may be contaminated by other ions, and the level of contamination may depend on the pressure in the proportional counter. The reason for this is as follows. The instrument consists of a proportional counter/solid state detector telescope. Ion species are identified by the energy they deposit in each detector. At certain low energies, the ion species are difficult to distinguish from one another. The "lowE" rates extend as far as possible into this energy range. As the pressure changes, the limiting energy for species identification changes somewhat and the automatic flux calculation algorithm may improperly include other species.