Galileo Spacecraft Pages
Appendix E. EPD File Structure (continued)
5. LEMMS PHA Block
Source: T. P. Armstrong, April 1985
The LEMMS PHA data are acquired in a cycle of 91 SCLK counts (91 packets of 2/3 second in length). During this 60 2/3 second interval 11 spectra from the A detector, one from E and one from F are acquired. Each spectrum consists of 47 energy channels accumulated in 2/3 of a second (12 degrees of rotation at the nominal spin rate). The shortest logical record interval for this data is 60 2/3 seconds. A logical record will consist of a variable number of physical records. There will be three records in the format listed below for each step position which occurs in this time interval. The groups of three records will have LEMMS data from Detectors A, E, and F. If all possible motor positions were present in the interval, there would be 24 physical records per logical record interval. Each physical record has approximately 12 k bytes.
|1||Spin rate at start||1 4-byte real|
|2||Spin rate at end||1 4-byte real|
|3||Number of spins in this average||1 4-byte real|
|4||Number of full sectors||1 4-byte integer|
|5||Step position of this record||1 4-byte integer|
|6||Detector flag: 0="fill," 1=A, 2=E, 3=F||1 4-byte integer|
|7||PHA(47,32) Detector A, E, or F Pulse Height Spectrum
|8||IPHADQ(47,32) Data presence and quality flag for item 6
|9||RA30(9,33) Count rates for detector A, E, or F
|10||IDQ(9,33) Data presence/quality flags
Next: 6. Rate Calc Block
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Updated 10/12/04, T. Hunt-Ward