Space Research Laboratory

GED

GED (Get Erne Data) is a set of IDL programs and auxiliary files for reading and manipulating ERNE level-2 and level-3 science data. In addition, ged is also the name of the main function of the system.

In principle there is only one ged program user needs to know: ged, an IDL function that acts as a front end for the other ged programs. The other functions are called automatically as needed based on the requested data type and prosessing parameter (IDL keyword) settings. However, an effective use of the system at its current state requires also some knowledge of what happens 'behind the scenes'. Specifically user should be aware what keywords are available to control the processing of the data in question. The available keywords depend on the 'lower level' functions that are used to read and process each data type.

Quick Refence

The Data stucture entries link to pages with information on the names and types of the fields of the corresponding structures. From the GED reader pages the user can check e.g., the set of available keywords. These keywords are acknowledged when making a ged request for the corresponding type of ERNE data.

Level-2

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All the level-2 data is read by the same reader function: ged_l2_a. The data types and the associated data structures are listed in the table below.

Level-2
Data type	f10	f30	f40	f50	Data structure	Description	Note
counters	x				TscCounters_a	ESU science counters
“		x			TscCounters_b	ESU science counters
”			x		TscCounters_c	ESU science counters
“				x	TscCounters_d	ESU science counters
10s_spectra	x				Tsc10sCntrs_a	LED+HED 10 second spectra
pn_spectra	x				TscEcntrs_a	LED+HED on-board spectra
led_spectra		x	x	x	TledEcntrs_b	LED on-board spectra
hed_spectra		x	x	x	ThedEcntrs_b	HED on-board spectra
led_pha	x	x	x	x	TscHeader_a	LED pulse height data (file input)	a
”	x	x	x	x	TledPHAevent_a	LED pulse height data (file input)	a
“	x	x	x	x	TledPHArecord_a	LED pulse height data (output)	b
hed_pha	x	x	x	x	TscHeader_a	HED pulse height data (file input)	a
”	x	x	x	x	ThedPHAevent_a	HED pulse height data (file input)	a
“	x	x	x	x	ThedPHArecord_a	HED pulse height data (output)	b
hed_electrons	x				ThedElectronCntrs_a	HED “electrons”
hed_relat		x	x	x	ThedElectronCntrs_b	HED “electrons”
hed_anisotropy_AN	x				ThedDirCntrs_a	HED dx-dy-profiles: 0-5	c
hed_anisotropy_BN	x				ThedDirCntrs_b	HED phi-theta tables: 0-5	c
hed_dirdistrN		x	x	x	ThedDirCntrs_c	HED phi-theta tables: 0-5	c

    ● a: INPUT, from a lev-2 file. For each measurement period ('minute'): Science Header
         followed by two bytes (fillMode and nEvents) and then nEvents number of PHA event
         structures for the period.
    ● b: OUTPUT, function result: array of records of the indicated type.
    ● c: N = anisotropy (direction distribution) channel number (0..5).

Level-3

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For level-3 there are different ged-functions depending on the data type and telemetry format. The indicated data structure is the one used in the corresponding disk file record. The actual reader output might differ depending on the selected filtering.

Level-3
Data type	f10	f40	f50	Data structure	GED reader	Description	Note
corr	x	x	x	Tcorr_a	ged_l3_corr	Counters used in data normalization
pHe_spectra	x			TobSpectra_a	ged_l3_spectra	proton and He onboard spectra
spectra		x	x	TobSpectra_b	”	p, He3 and He4 onboard spectra
led_pha	x	x	x	TledPartData_a	ged_l3_pha	LED pulse height data
hed_pha	x	x	x	ThedPartData_a	“	HED pulse height data
hed_pha_calib	x	x	x	ThedPartData_c	”	HED pulse height calibration data	a
led_dirspectra		x	x	TledDirSpectra_a	ged_l3_leddirspectra	LED direction spectra	b

    ● a: Calibration data is available for selected periods only.
    ● b: Disk file structure indicated. The nominal reader output will have the lower
         energy channels, which are covered only by the LED-I (thin D1 detectors), discarded.