ErgSat/Hep

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High-Energy Electron Experiments (HEP)

Members

  • PI
    • Takefumi Mitani (JAXA/ISAS)
  • Co-I
    • Takeshi Takashima (JAXA/ISAS)
    • Satoshi Kasahara (Univ. of Tokyo)

Rules of the Road

  • For the general data policy for the ERG satellite, please refer to this webpage.

Specific to HEP Data

Rules of the Road for HEP Level 2 data

  • For details of the instrument, please refer to the following article:
    • Mitani, T., Takashima, T., Kasahara, S., Miyake, W., and Hirahara, M. (2018). High-energy electron experiments (HEP) aboard the ERG (Arase) satellite. Earth, Planets and Space, 70(1), 77. https://doi.org/10.1186/s40623-018-0853-1
  • The users should be aware that the current version of Level-2 data may still contain contamination to flux values due to penetration of higher energy electrons and protons. The users should analyze data carefully not only for quantitative studies but also qualitative examination.
  • It is highly recommended to establish contact and work together with the PI team from the early stage of the user's study. Level-2 data can be updated in future if necessary. Please make sure to use the latest version of data for the analyses.
  • Further information on the data can be found at the following wiki page: https://ergsc.isee.nagoya-u.ac.jp/mw/index.php/ErgSat/Hep
  • Questions, comments, and any feedback relevant to the data should be directed to the HEP team (E-mail: erg_hep_info at isee.nagoya-u.ac.jp).

Updates on the Instrument Status, Data, Calibration, and Notes

  • 20170114
    • N/A
Dates not in operation
HEP-L HEP-H
1 2017-04-19 16:04 - 2017-04-19 17:10
2 2017-04-21 12:35 - 2017-04-22 05:04
3 2017-04-23 04:40 - 2017-04-23 10:33
4 2017-06-20 13:12 - 2017-06-20 17:26 2017-05-26 08:35 - 2017-05-29 13:10
5 2017-07-10 15:48 - 2017-07-12 08:57 2017-08-14 08:36 - 2017-08-14 08:52
6 2017-07-23 07:01 - 2017-07-24 03:37
7 2017-08-10 09:37 - 2017-08-10 11:27
8 2017-08-11 04:34 - 2017-08-11 05:13
9 2017-08-12 16:56 - 2017-08-14 08:50
10 2017-08-20 15:39 - 2017-08-21 06:52


Past articles archived here


Instrument Specifications

  • Energy range: ~70 keV to ~1 MeV for HEP-L, ~0.7 to ~2 MeV for HEP-H
  • Energy resolution: ~11% at 300 keV (FWHM) for HEP-L, ~17% at 750 keV (FWHM) for HEP-H
  • Energy steps: 16 energy bins for HEP-L and HEP-H
  • Particle species: Electron
  • Sensor field of view: 10° (azimuth) × 180° (elevation)
  • Number of elevation channel: 15 (5 channels for each SSD)
  • Geometrical factor
    • ~4×10-6 to ~3×10-5 [cm2 str] for HEP-L
    • ~6×10-5 to ~1×10-4 [cm2 str] for HEP-L
  • Time resolution: ~ 8s for full 3-D distribution function

Observation Modes

  • Normal observation mode
    • Generate a 3-D distribution function per satellite's spin (~8s).

Observation Mode Changes

  • March, 20, 2017
    • The instrument started the regular observations.
  • Jun 8-21, 2017
    • Some operations were performed to optimize the observation mode. Data collection was suspended intermittently.
  • 6 UT, Jun 21, 2017
    • The regular observation was resumed (to present).

Calibration Information

  • Caution on the lowest energy channel of HEP-L and HEP-H
    • The 0th energy channel of HEP-L and the 0th energy channel of HEP-H are designed to measure all incident electrons with energies below 70 keV and 100 keV, respectively. However, these energy-integrated channels actually have ambiguity in lowest threshold energy for detection, which introduces some level of uncertainty in differential flux value. Currently the threshold energies derived by a coordinated simulation are used to convert raw count values to flux values for the lowest energy bins. The data user should be aware that differential flux values for these channels in data files might differ from true flux values.

Science Data Products

Level-2 3-D flux Data
Name Description Dimension Nominal Time Resolution Data Load Routine for SPEDAS
Epoch_L Time label in the CDF_TT2000 format for HEP-L for each spin sector (time) 0.5s (nominal time interval for each spin sector) ----
rawcnt_L raw count of HEP-L for each spin sector (time) x 16(energy) x 15(elevation ch) 0.5s erg_load_hep
FEDU_L Uni-directional differential number flux for HEP-L for each spin sector (time) x 16(energy) x 15(elevation ch) 0.5s erg_load_hep
FEDU_L_Energy Energy bin boundaries for HEP-L 2(min,max) x 16(energy) ---- erg_load_hep
FEDU_L_Angle_sga Looking direction in SGA coordinates of each elevation channel for HEP-L 2(elevation, azimuth) x 15(elevation ch) ---- erg_load_hep
FEDU_L_Angle_gse Looking direction in GSE coordinates of each elevation channel for HEP-L (time) x 2(elevation, azimuth) x 15(elevation ch) 0.5s erg_load_hep
FEDU_L_quality_index Data quality flag for HEP-L data (time) x 16(energy) x 15(elevation ch) 0.5s erg_load_hep
livetime_ratio_L Ratio of live time of detectors to the entire measurement time for HEP-L (time) x 3(head) 0.5s erg_load_hep
Epoch_H Time label in the CDF_TT2000 format for HEP-H for each spin sector (time) 0.5s (nominal time interval for each spin sector) erg_load_hep
rawcnt_H raw count of HEP-H for each spin sector (time) x 11(energy) x 15(elevation ch) 0.5s erg_load_hep
FEDU_H Uni-directional differential number flux for HEP-H for each spin sector (time) x 11(energy) x 15(elevation ch) 0.5s erg_load_hep
FEDU_H_Energy Energy bin boundaries for HEP-H 2(min,max) x 11(energy) ---- erg_load_hep
FEDU_H_Angle_sga Looking direction in SGA coordinates of each elevation channel for HEP-H 2(elevation, azimuth) x 15(elevation ch) ---- erg_load_hep
FEDU_H_Angle_gse Looking direction in GSE coordinates of each elevation channel for HEP-H (time) x 2(elevation, azimuth) x 15(elevation ch) 0.5s erg_load_hep
FEDU_H_quality_index Data quality flag for HEP-H data (time) x 11(energy) x 15(elevation ch) 0.5s erg_load_hep
livetime_ratio_H Ratio of live time of detectors to the entire measurement time for HEP-H (time) x 3(head) 0.5s erg_load_hep
Level-2 Omniflux Data
Name Description Dimension Nominal Time Resolution Data Load Routine for SPEDAS
Epoch_L Time label in the CDF_TT2000 format for HEP-L (the start time of each spin) (time) 8s (nominal spin period) erg_load_hep
FEDO_L Omni-directional differential flux for HEP-L (time) x 16(energy) 8s erg_load_hep
FEDO_L_Energy Energy bins for HEP-L 2(min,max) x 16(energy) 8s erg_load_hep
Epoch_H Time label in the CDF_TT2000 format for HEP-H (the start time of each spin) (time) 8s erg_load_hep
FEDO_H Omni-directional differential flux for HEP-H (time) x 11(energy) 8s erg_load_hep
FEDO_H_Energy Energy bins for HEP-H 2(min,max) x 11(energy) 8s erg_load_hep


Level-3 Data
Name Description Dimension Nominal Time Resolution Data Load Routine for SPEDAS

Data Inventory (Data Archive Status)

Data repository: http://ergsc.isee.nagoya-u.ac.jp/data/ergsc/satellite/erg/hepe/

Name Processed until Latest Calibration Version Remarks