JUICE RADiation–hard Electron Monitor (RADEM) bundle ================================================================================================================================================================================== ================================================================================================================================================================================== This bundle contains the following primary collections: data_raw - raw data products browse_raw - browse images for data products in the data_raw collection document - documentation miscellaneous - miscellaneous documents or files ================================================================================================================================================================================== ************INSTRUMENT INFORMATION************ ================================================================================================================================================================================== The RADiation–hard Electron Monitor (RADEM) is an instrument designed for the ESA JUpiter ICy moons Explorer (JUICE) space mission. As a part of the Cosmic Vision programme, JUICE will spend over three years exploring the Jovian system and its icy moons, in particular: Ganymede, Callisto and Europa. RADEM's main objective is to serve as an on–board radiation monitor providing information on particle fluxes and their energy spectra. It consists of four detector heads: 1) Electron Detector Head (EDH) - designed to measure electrons with energies between 0.3-40 MeV covering fluxes up 10^9 particles/cm^2/s without saturation. 2) Proton Detector Head (PDH) - designed to measure protons with energies between 5-250 MeV with a peak flux of to 10^8 particles/cm^2/s. 3) Heavy Ion Detector Head (HIDH) - designed to measure Helium to Oxygen with a Linear Energy Transfer from 0.1 to 10 MeV*cm^2/mg with a maximum flux over 10^5 particles/cm^2/s. 3) Directional Detector Head (DDH) - designed to measure electron angular distribution of ~35% of the sky from 0.3 to 2.0 MeV without any energy resolution. Each detector is connected to a readout Application–Specific Integrated Circuit (ASIC), designed especially for the JUICE mission, with the exception of the PDH and HIDH which share an ASIC. The ASIC is highly reconfigurable being able to completely change the sensitivity of each detector. RADEM will change configuration over time meaning that its sensitivity will also change. A list with the periods corresponding to each configuration as well as their settings can be found on the EAICD. RADEM is prepared to work in the following modes: - Calibration - Safe - Normal ================================================================================================================================================================================== ************DATA FORMAT************ ================================================================================================================================================================================== RADEM data is stored in two .cdf file types with corresponding labels (.lbx): sc - science and hk - housekeeping The hk files have operational information including the RADEM's operation mode. Science data is only acquired when RADEM_MODE is in Normal mode. However, flight calibrations are also made in this Normal mode - refer to the **CAVEATS/WARNING** section in this file for more information. The sc files contain the measurements made by the detectors integrated in time (default is 60s - check INTEGRATION_TIME variable in the files). In the data_raw, detector observations are split into eight ELECTRONS bins (EDH), eight PROTONS bins (PDH), two HEAVY_IONS bins (HIDH), 31 DD bins (DDH), and 12 CUSTOM bins (mix of EDH and PDH - check the EAICD). The sensitivity of each bin depends on the configuration (see the EAICD for more information). ================================================================================================================================================================================== ************CAVEATS/WARNINGS************ ================================================================================================================================================================================== 14.04.2023 - 30.04.2023: NECP - Non scientific data. 30.08.2023 - Onwards: A few directional sensors are fully masked/shadowed by the spacecraft (DD Bins 8, 9, 16-19, 25-28). 30.08.2023 - Onwards: The first Heavy ion detector diode is unresponsive since launch. 30.08.2023 - 30.08.2023: RADEM Configuration 1: detectors in single coincidence. 30.04.2024 - 30.04.2024: Software test - do not use data. 21.05.2024 - 28.05.2024: Threshold scan (flight calibration) - do not use data. 09.07.2024 - 09.07.2024: RADEM Configuration 2. Large reconfiguration of the coincidence logic and its thresholds. 04.08.2024 - 04.08.2024: Third re-configuration. Small reconfiguration of Proton Bin 3. ================================================================================================================================================================================== ************CONFIGURATIONS************ ================================================================================================================================================================================== Configuration 1 --------------- In this configuration all detectors work in single coincidence. The main objective was to maximize its sensitivity to cosmic rays to test all sensors. This means that all detectors are measuring electrons, protons and heavy ions at the same time. However, they are more sensitive to protons and to heavy ions than to electrons. Moreover, proton fluxes are typically much higher than that of heavy ions so the response to protons should dominate even with large contamination from electrons and heavy ions. Configuration 2 --------------- The PDH was changed to multiple coincidence. The CUSTOM channels are now being used. The thresholds of all detectors with the exception of the second HIDH were changed significantly. PROTONS variable are well separated in energy (see EAICD) with almost no contamination from either electrons or heavy ions. ELECTRONS variable measure electrons above a certain energy (see EAICD or metadata). The first bin is contaminated by low energy protons (~7.8 MeV). All bins are contaminated by high energy protons (>~ 45-70 MeV). DD bins measure electrons above 0.3 MeV (0º, and 22.5º zenith sensors), 0.35 MeV (45º zenith sensors), and 0.5 MeV (67.5º sensors). All bins are contaminated by high energy protons (>~ 40-50 MeV). HEAVY_IONS bin 2 measures ions with energies between 30.9-90 MeV/nucleon and above 100 MeV/nucleon. CUSTOM channels measure a variety of particles and energies (check EAICD) ==================================================================================================================================================================================