Space Research Laboratory

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===== 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. 

  * [[ged_progs|Programs]]
  * [[ged_data|ERNE Data]]
  * [[ged_structs|Data Structures]]
  * [[ged_params|Parameters]]
  * [[ged_examples|Examples]]

==== 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  |

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

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=== 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  |

<typo fs:smaller; ff:courier>
(nbsp)(nbsp)(nbsp)(nbsp)(bcircle)(nbsp)a: Calibration data is available for selected periods only.\\
(nbsp)(nbsp)(nbsp)(nbsp)(bcircle)(nbsp)b: Disk file structure indicated. The nominal reader output will have the lower\\
(nbsp)(nbsp)(nbsp)(nbsp)(nbsp)(nbsp)(nbsp)(nbsp)(nbsp)energy channels, which are covered only by the LED-I (thin D1 detectors), discarded.
</typo>

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