NGRM - Next Generation Radiation Monitor

NGRM data is provided as part of the SWE Service Network’s General Data Services.
Access it via the SWE Data Browser or through HAPI.

The Instrument

NGRM is the second Space Weather instrument flying as part of ESA’s Distributed Space weather Sensor System (D3S). The first NGRM unit was placed on the GEO European Data Relay System - C (EDRS-C) spacecraft, the second is hosted on board the Low Earth Orbit (LEO) Sentinel-6 Michael Freilich (S6-MF) and the third one is on board the first GEO Meteosat Third Generation-Imager (MTG-I 1).

NGRM entails two particle sensors, the electron detector (ED) consisting of 16 circular silicon strip detectors with a circular step collimator on top, and the stacked detector (SD) comprising an assembly of seven silicon detectors layered with several aluminum and tantalum degraders. Incident charged particles are registered according to the detection logic in one of 16 electron or one of 10 proton channels. [L. Desorgher et al., 2013]

ED and SD have been calibrated with both experimental and numerical means. The electron (proton) response functions (RF) of ED and SD have been derived using 4π-and linear-beam GEANT4 simulations slightly re-adjusted with experimental results based on the unit’s experimental calibrations at the Proton Irradiation and the Electron Monochromator Facilities at Paul Scherrer Institute, Switzerland.

NGRM flux datasets

For the derivation of electron and proton flux products, two different methods have been applied; the Bow-Tie (BT) analysis and the Genetic Correlative Unfolding Method (GenCORUM).

The BT analysis applies to the response functions of the detectors channels and allows the derivation of a scaling factor for the conversion of the detector’s count rates to flux products for an energy value that minimizes the uncertainties expected at the encountered space radiation environment (cf. Sandberg et al 2019)

The GenCORUM [Aminalragia-Giamini et. al 2018] is an artificial intelligence method which employs a Cased-Based Reasoning (CBR) process coupled with a Genetic Algorithm (GA). The CBR process performs an initial crude unfolding taking into account the count-rates measured from all the detector channels simultaneously, and the GA optimizes the resulted flux values.

The characteristics of the provided NGRM Level 1 (L1) flux are provided below. Note that the datasets include also timestamps, ephemeris data (in the ECI coordinate system) and magnetic coordinates (L, L*, MLT etc). The magnetic coordinates were derived using the UNILIB library (accessible here) assuming the IGRF model for the internal, and the quiet Olson-Pfitzer 1977 model for the external magnetic field components.

LEO S6-MF/NGRM L1 datasets

The Sentinel-6 Michael Freilich (S6-MF) satellite was launched on November 2020 in a LEO with 1336 km orbit altitude and 66° orbit inclination.
The current data release of S6-MF/NGRM flux Level 1 datasets consists of

eumetsat_sentinel6mf_ngrm_science_ep_l1_bt_v1

which includes proton omnidirectional differential fluxes FPDO[ (cm2 s sr MeV)-1 ] and integral fluxes FEIO[ (cm2 s sr)-1] estimated using simple geometric factors derived with a BT method, and the

eumetsat_sentinel6mf_ngrm_science_ep_l1_bt_v1

which includes electron omnidirectional differential fluxes FEDO[ (cm2 s sr MeV)-1 ] de-convoluted using the GenCORUM. The energy bins and the respective energies [MeV] per particle and spectra type of the provided datasets are given in Table 1

Table 1. Energy bins of the S6-MF/NGRM flux Level 1 datasets

Energy Bin	FEDO_ENERGY	FEIO_ENERGY	FPDO_ENERGY
1	0.180	0.15	5.0
2	0.270	0.25	9.0
3	0.400	0.35	10
4	0.600	0.4	15
5	0.880	0.5	50
6	1.30	0.65	73
7	1.93	0.8	-
8	2.90	0.9	-
9	3.40	1.0	-
10	4.00	1.1	-
11	-	1.2	-
12	-	1.3	-
13	-	1.4	-
14	-	1.5	-
15	-	1.6	-
16	-	1.7	-

For more details on the S6-MF/NGRM data sets, please consult the Data Description Document

GEO EDRS-C/NGRM L1 datasets

The EDRS-C spacecraft, launched on August of 2019, is located in GEO at 31° East.
The current data release of EDRS-C/NGRM flux Level 1 datasets consists of

gsoc_edrsc_ngrm_spid204030251_science_ep_l1_bt_v3

which includes proton omnidirectional differential fluxes FPDO[ (cm2 s sr MeV)-1 ] and integral fluxes FEIO[ (cm2 s sr)-1] estimated using simple geometric factors derived with a BT method, and the

gsoc_edrsc_ngrm_spid204030251_science_ep_l1_gc_v3

which includes electron omnidirectional differential fluxes FEDO[ (cm2 s sr MeV)-1 ] de-convoluted using the GenCORUM. The energy bins and the respective energies [MeV] per particle and spectra type of the provided datasets are given in Table 2

Table 2. Energy bins of the EDRS-C/NGRM flux Level 1 datasets

Energy Bin	FEDO_ENERGY	FEIO_ENERGY	FPDO_ENERGY
1	0.180	0.209	5.5
2	0.270	0.235	8.8
3	0.400	0.286	14.8
4	0.600	0.338	33.9
5	0.880	0.455	46.1
6	1.30	0.594	76.2
7	1.93	0.736	-
8	2.90	0.841	-
9	3.40	0.944	-
10	4.00	1.043	-
11	-	1.20	-
12	-	1.40	-
13	-	1.60	-
14	-	1.80	-
15	-	2.00	-
16	-	2.20	-

For more details on the EDRS-C/NGRM data sets, please consult the Data Description Document

The following paper discusses the released EDRS-C/NGRM data:
I. Sandberg et al., 'First results and analysis from ESA Next Generation Radiation Monitor unit on-board EDRS-C,' in IEEE Transactions on Nuclear Science, doi: 10.1109/TNS.2022.3160108.

The SWE Service Network also provides a series of products based on EDRS-C/NGRM measurements:

Figure 1. Illustration of ESA’s Distributed Space Weather Sensor System concept planned to be realised through hosted payload missions as well as dedicated small satellite missions.