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JEDI (Jupiter Energetic-particle Detector Instrument), is an instrument on the Juno spacecraft orbiting planet Jupiter. It is part of a suite of instruments to study the magnetosphere of Jupiter. JEDI consists of three identical detectors that use microchannel plates and foil layers to detect the energy, angle, and types of ion within a certain range. It can detect electrons between 40 and 500 keV (Kilo electron-volts), and hydrogen and oxygen from a few tens of keV to less than 1000 keV (1 MeV). JEDI uses radiation hardened Application Specific Integrated Circuits (ASIC)s. JEDI was turned on in January 2016 while still en route to Jupiter to also study interplanetary space.
JEDI is designed to collect data on "energy, spectra, mass species (H, He, O, S), and angular distributions"; the plan is to study the energies and distribution of charged particles. It can detect them at between 30 keV and 1 GeV, whereas JADE, another instrument on the spacecraft, is designed to observe below 30 keV. One of the concepts being studied is that energy from Jupiter's rotation is being converted into its atmosphere and magnetosphere.
It is radiation hardened to collect in situ data on the planet's auroral magnetic field lines, the equatorial magnetosphere, and the polar ionosphere It was built by the Johns Hopkins University Applied Physics Laboratory (APL). One of the goals is to understand the aurora, and how particles are accelerated to such high speeds. One of the mysteries of Jupiter is that X-rays are emitted from the poles, but do not seem to come from the auroral ring.
Each detector has a field of view of 120 degree by 12 degrees, and they are positioned to provide a 360 degree (a full circle) view of the sky along that axis.
JEDI can detected particles from 30 to 1000 keV including:
In relation to other space missions, an instrument on the Earth-orbiting Van Allen Probes (launched 2012), called RBSPICE, is nearly identical to JEDI. This type of instrument is also similar to the PEPSSI instrument on New Horizons (Pluto/Kupiter probe).