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Direct-events are the count rates detected in each time-of-flight (TOF) bin. There are 256 bins. The values in each bin are accumulated over a superspin (32 spins) and every other bin is trickled down in the spin headers of the next superspin. The even-numbered (0-254) bins are reported in even number superspins and the odd numbered (1-255) bins in odd-numbered superspins. Superspins are numbered from 0-7. The superspin number can be determined by dividing the spin number (0-255) by 32.
Starting early in the mission, the time-of-flight bins started to loose the ability to detect ions, probably as a result of the radiation leak. As a result, TIDE lost its ability to distinguish masses because masses are defined by a range of TOF bins. See TIDE Mass Calibration (mass_calib.v8) for details about mass descriptions.
Daily direct-event summary color spectrogram plots were created from 03/20/96 to 02/22/00. Monthly trend spectrograms were created from April 1996 to January 2000. The .gif and .pdf versions of these files are stored in the MSFC and GSFC plot archives in /archive/po_tid_plt_yymm/spectrograms/direct_events/ and have the filenames: tyymmddh1m1_h2m2.sg_de and tyymm_trend.de_sum. Each plot has a panel for the 7 polar angle channels. Color is logged counts/sample. The panel vertical axis is TOF bin number and horizontal axis is time in hours or days. Mass resolution was pretty much gone by September 1996.
The daily spectrograms were created briefly after the voltage on the Start MCP voltage was changed from -2600 to -3400 volts. Testing started on 09/28/06 and the voltage was permanently changed on 10/06/06. The daily spectrograms were created for 09/28/06 through 04/21/07.
The direct-event data can also be plotted as line plots. These were typically used during real-time commanding early in the mission and they are created at the same time and in the same plot file as the count rate strip charts. Some examples are kept in tideteam/start_mcp_ramp/1996/strip-charts and tideteam/2006_ions/strip-charts.
Both the line plots and the spectrograms can be created using the TIDE processing software.
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Last Updated: September 2008