urn:nasa:pds:context:instrument:mimi-inca.co 1.0 1.20.0.0 Product_Context MIMI INCA 2023-07-05 1.0 Initial version describing MIMI INCA as a unique instrument, rather than as a component of the MIMI instrument. urn:nasa:pds:context:instrument_host:spacecraft.co::1.0 instrument_to_instrument_host Krimigis, S.M., D.G. Mitchell, D.C. Hamilton, S. Livi, J. Dandouras, S. Jaskulek, T.P. Armstrong, J.D. Boldt, A.F. Cheng, G. Gloeckler, J.R. Hayes, K.C. Hsieh, W.-H. Ip, E.P. Keath, E. Kirsch, N. Krupp, L.J. Lanzerotti, R. Lundgren, B.H. Mauk, R.W. McEntire, E.C. Roelof, C.E. Schlemm, B.E. Tossman, B. Wilken, and D.J. Williams, Magnetosphere Imaging Instrument (MIMI) on the Cassini Mission to Saturn/Titan, Space Sci Rev. 114, 233-329 (2004). https://doi.org/10.1007/s11214-004-1410-8 reference.KRIMIGISETAL2004 Kusterer, M.B., L.M. Burke, Level 1A File Layouts, Cassini/MIMI Data Analysis Center Level 1A File Layouts, The Johns Hopkins University Applied Physics Laboratory Document, Revision 18, December 2003. reference.KUSTERER-BURKE2003 Manweiler, J.W., W.A. Rasmuss, and S. Joy, MIMI Standard Data Products and Archive Volume Software Interface Specification, v2.1, JPL Document D-31634, Cassini document IO-AR-006, 2005. reference.MANWEILERETAL2005 MIMI Ion Neutral Camera Charged Particle Detector Spectrum Analyzer not applicable not applicable The text of this instrument description has been abstracted from the instrument paper [KRIMIGISETAL2004]: Krimigis, S.M., Magnetosphere Imaging Instrument (MIMI) on the Cassini Mission to Saturn/Titan, in Space Science Reviews, Springer Science and Business Media, B.V., formerly Kluwer Academic Publishers B.V., Vol. 114, No. 1-4, pp. 233-329, December 2004. Calibration: ============ Calibration processes are accomplished via both flight software and ground processing software. Flight software is used primarily to accommodate variations in measurements due to spacecraft motion. Ground based calibration is accomplished through a combination of calibration data values (see COMIMI_0000) coupled with various algorithms to generate particle flux from measured count rates. Operational Modes: =========================== The INCA detector has the capability to be placed in either ion mode or neutral mode. Ion mode indicates that the potential of the deflection plates is set to zero so that ions are also counted along with neutrals. Neutral mode identifies that there is a potential applied to the plates that will cause the ions to deflect away from the entrance aperture and not be counted. The efficiency of this process is strongly dependent upon the applied plate potential. The applied plate potential is a configurable parameter within the system and is based upon the science goals, dust environment, and the expected plasma and high energy particle distributions. Operational Considerations: =========================== The MIMI power consumption is nomially ~19.0 W. Typical operations include the capability to sense 6-7 orders of magnitude in particle flux over a dynamic energy range for electrons of 30 KeV to 5 MeV and for ions from 3 KeV to 160 MeV. Data quality is affected by direct sun exposure into the instruments and INCA operations are tailored to reduce the possibility of direct dust particle impacts into the sensor aperture during ring crossings. Sensors: ========== The MIMI experiment consists of three independent sensors: Charge Energy Mass Spectrometer (CHEMS), Ion Neutral Camera (INCA), and Low Energy Magnetospheric Measurements (LEMMS). Each sensor has specific targeted energies and populations to be examined and collectively provide the ability to fully characterize the energetic charged and neutral particle population in the Saturnian Magnetosphere as well as the Solar Wind, the Jovian Magnetosphere, and the Earth Magnetosphere. Each sensor is a combination of geometric components, silicon detectors, micrpchannel plates, and electronics/software components that give them the ability to fully answer the missions scientific objectives. When the spacecraft is spinning the MIMI sensors obtain measurements over a full four pi steradians. The different MIMI sensors share common electronics and provide complimentary measurements of energetic plasma distributions, composition, and energy spectrum, and the interaction of that plasma with the extended atmosphere and moons of Saturn. The INCA sensor is separately mounted and nearly co-aligned with the remote sensing instruments, with a field of view of 120 degrees in latitude and 90 degrees in azimuth, centered on a vector rotated 9.5 degrees toward the spacecraft +x axis from the -y axis. INCA makes two different types of measurements. It obtains the directional distribution, energy spectra, and crude composition of magnetospheric ions between 7 keV/nuc and 500 keV/nuc and it makes remote images of the global distribution of the energetic neutral emission of hot plasmas in the Saturnian magnetosphere, measuring the composition and energy spectra of those energetic neutrals for each image pixel. Frames diagram -------------- All MIMI telescope directions are described in terms of the spacecraft fixed frame. INCA is separately mounted and nearly co-aligned with the remote sensing instruments with a latitudinal field of view of 120 degrees and an azimuthal field of view of 90 degrees centered on a vector rotated 9.5 degrees toward the spacecraft +x axis from the -y axis. There are no otherwise specifically defined Cassini MIMI frames. Electronics: ============ Signals from the sensors are first processed by the analog electronics and then by the digital processing unit (DPU). With respect to INCA thebdata is shifted into appropriate bins based upon the current spacecraft orientation and spin rates. The INCA instrument has the ability through the use of high voltage potentials applied to the aperture plates to deflect ions away from the entrance slit and instead image neutral particles. When the high voltage supply is turned off then the instrument see both neutrals and ions. The DPU unit's primary function is to catalog incoming particle measurements based upon underlying logic and to count events in accumulation bins. The DPU also packages the data along with the instrument housekeeping data (instrument states) and then integrated into telemetry for broadcast to ground station. Parameters that control the high voltage supplies, the selection of priority counters etc, are expected to be updated periodically under normal operating conditions. Data compression and sampling techniques are used to maximize data return within the bandwidth allocated to the experiment.