Table of Contents
Wiki for Solar Particle Monitor (SPM) onboard BepiColombo Mercury Magnetospheric Orbiter (BC/MMO)
The Solar Particle Monitor (SPM) onboard MMO is a particle detector which is part of the housekeeping sensors (not the scientific instruments) of MMO. It consists of two silicon photo diodes (SPM1 and SPM2) with an effective area of 10 mm x 10 mm and a depletion layer thickness of 0.3 mm. Each sensor collects counts of incident particles with four different deposited energy channels (Lv.1, 2, 3, and 4). The silicon sensors are covered by a magnesium chassis and the SPM is located inside the MMO spacecraft. Radiation incident on the SPM has already passed through the satellite structure, the SPM chassis, and the chassis of other instruments, and hence the energy of the radiation coming from outer space is not measured as it is.
Members
Instrument team
- Go Murakami (JAXA, Japan)
- Haruka Ueno (JAXA, Japan)
- Takeshi Takashima (JAXA, Japan)
- Shoya Matsuda (Kanazawa University, Japan)
Data contact at Mio-SC
- Tomoaki Hori (CHS, ISEE, Nagoya Univ., Japan)
- Shota Chiba (CHS, ISEE, Nagoya Univ., Japan)
Rules of the Road for the data users
Updates on the instrument status, data, and any notes
- N/A
Instrument Specifications
- A pair of two identical pariticle monitors (SPM1 and SPM2) employing a 10 mm x 10 mm x 0.3 mm solid state dector (SSD)
- The energy range: >70 keV (as deposited energy, not incident energy)
Data release/version history
- Oct. 2025: the first release of Lv.2pre data (data ver.: r02-v02-00) to registered users.
- Dec. 2024: the first release of Lv.2pre data (data ver.: r01-v01-00) to registered users.
Calibration Information
- A set of Geant4 simulations were performed to estimate the actural incident proton energies of Lv.2 to 4 energy channels. For details, please refer to Kinoshita et al. (2025) at https://doi.org/10.1029/2024JA033147.
Science Data Products
==========Level-2pre (cruise phase) data products==========
Level-2pre count/flux Data (uncalibrated / partially calibrated)
| Data array name | Description | Dimension | Nominal time resolution | Remarks |
|---|---|---|---|---|
| epoch | Time labels in the CDF_TT2000 format | (time) | ~32 s | |
| strtime | Time labels in UTC string | (time) | ~32 s | |
| time_width | Data accumulation period in second | (time) | ~32 s | |
| mdp_ti | Time indicators given by Mission Data Processor (MDP) | (time) | ~32 s | |
| spm1_lv1_cnt | Raw count registered by SPM1 for Lv.1 channel (deposited energy: 0.0732-0.3455 MeV) | (time) | ~32 s | |
| spm1_lv2_cnt | Raw count registered by SPM1 for Lv.2 channel (deposited energy: 0.3455-0.7962 MeV) | (time) | ~32 s | |
| spm1_lv3_cnt | Raw count registered by SPM1 for Lv.3 channel (deposited energy: 0.7962-1.1481 MeV) | (time) | ~32 s | |
| spm1_lv4_cnt | Raw count registered by SPM1 for Lv.4 channel (deposited energy: >1.1481 MeV) | (time) | ~32 s | |
| spm2_lv1_cnt | Raw count registered by SPM2 for Lv.1 channel (deposited energy: 0.0732-0.3455 MeV) | (time) | ~32 s | |
| spm2_lv2_cnt | Raw count registered by SPM2 for Lv.2 channel (deposited energy: 0.3455-0.7962 MeV) | (time) | ~32 s | |
| spm2_lv3_cnt | Raw count registered by SPM2 for Lv.3 channel (deposited energy: 0.7962-1.1481 MeV) | (time) | ~32 s | |
| spm2_lv4_cnt | Raw count registered by SPM2 for Lv.4 channel (deposited energy: >1.1481 MeV) | (time) | ~32 s | |
| spm1_lv2_proton_flux | Estimated H+ differential number flux from SPM1 Lv2 at the mode energy of 135 MeV | (time) | ~32 s | Based on Kinoshita et al. [JGR, 2025] |
| spm1_lv3_proton_flux | Estimated H+ differential number flux from SPM1 Lv3 at the mode energy of 68.7 MeV | (time) | ~32 s | Based on Kinoshita et al. [JGR, 2025] |
| spm1_lv4_proton_flux | Estimated H+ differential number flux from SPM1 Lv4 at the mode energy of 44.7 MeV | (time) | ~32 s | Based on Kinoshita et al. [JGR, 2025] |
| spm2_lv2_proton_flux | Estimated H+ differential number flux from SPM2 Lv2 at the mode energy of 129 MeV | (time) | ~32 s | Based on Kinoshita et al. [JGR, 2025] |
| spm2_lv3_proton_flux | Estimated H+ differential number flux from SPM2 Lv3 at the mode energy of 73.5 MeV | (time) | ~32 s | Based on Kinoshita et al. [JGR, 2025] |
| spm2_lv4_proton_flux | Estimated H+ differential number flux from SPM2 Lv4 at the mode energy of 54.9 MeV | (time) | ~32 s | Based on Kinoshita et al. [JGR, 2025] |