KPL/IK COSIMA Instrument kernel =========================================================================== This instrument kernel (I-kernel) contains COSIMA parameters and field-of-view definition. Version and Date --------------------------------------------------------------------------- Version 1.4 -- July 27, 2017 -- Marc Costa Sitja, ESAC/ESA Jouni Ryno, FMI Updated instrument description. Corrected FOV Angular Size and IFOV definitions. Version 1.3 -- December 22, 2005 -- Jorge Diaz del Rio, RSSD/ESA Corrected FOV Angular Size and IFOV definitions. Version 1.2 -- December 19, 2005 -- Herwig Hoefner, MPE Re-corrected field of view, reference [7] is correct, do does [5] drawings. Table in [5] will be updated. Version 1.1 -- December 8, 2005 -- Martin Hilchenbach, MPS Corrected field of view [7]. Version 1.0 -- March 15, 2005 -- Boris Semenov, NAIF/JPL Version number change for the first official release. Version 0.1 -- September 2, 2004 -- Boris Semenov, NAIF/JPL Filled in instrument overview section (copied from [6]). Version 0.0 -- August 5, 2004 -- Boris Semenov, NAIF/JPL Initial release. References --------------------------------------------------------------------------- 1. ``Kernel Pool Required Reading'' 2. ``C-kernel Required Reading'' 3. ``COSIMA EID, Part B'', ROS-EST-RS-3011/EID B, 2001-05-15 4. Rosetta Frames Definition Kernel (FK), latest version. 5. ``COSIMA Users Manual'', RO-ROS-MAN-1009, 2002-12-18 6. ESA Science and Technology Web Server, Rosetta Instruments Area, http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=35061 7. RO-COS-TN-51061, Mechanical Interface Drawings 8. E-mail from Jouni Ryno (Jouni.Ryno@fmi.fi), Subject: ``[SPICE Service]: COSIMA Instrument Kernel Review'', 30th May 2017 Implementation Notes -------------------------------------------------------- Applications that need SPICE I-kernel data must ``load'' the I-kernel file, normally during program initialization. Loading the kernel using the SPICELIB routine FURNSH causes the data items and their associated values present in the kernel to become associated with a data structure called the ``kernel pool.'' The application program may then obtain the value(s) for any IK data item using the SPICELIB routines GDPOOL, GIPOOL, GCPOOL. Routine GETFOV may be used if the file contains instrument field-of-view (FOV) specification. See [1] for details. This file was created with, and can be updated with a text editor or word processor. Conventions for Specifying Data -------------------------------------------------------- Data items are specified using ``keyword=value'' assignments [1]. All keywords referencing values in this I-kernel start with the characters `INS' followed by the NAIF Rosetta instrument ID code, constructed using the spacecraft ID number (-226) followed by the NAIF three digit ID number for COSIMA (140). The remainder of the keyword is an underscore character followed by the unique name of the data item. For example, the boresight of the COSIMA FOV is specified by INS-226140_BORESIGHT The upper bound on the length of all keywords is 32 characters. If a keyword is included in more than one file, or if the same keyword appears more than once within a single file, the last assignment supersedes any earlier assignments. Overview -------------------------------------------------------- From [6]: COSIMA (Cometary Secondary Ion Mass Analyser) is a secondary ion mass spectrometer equipped with a dust collector, a primary ion gun, and an optical microscope for target characterization. Dust from the near comet environment is collected on a target. The target is then moved under a microscope where the positions of any dust particles are determined. The cometary dust particles are then bombarded with pulses of indium ions from the primary ion gun. The resulting secondary ions are extracted into the time-of-flight mass spectrometer. The core of the COSIMA instrument is a time-of-flight (TOF) secondary ion mass spectrometer (SIMS) equipped with a dust collector, a primary ion gun, and an optical microscope (COSISCOPE) for target characterization. Once one of the targets on the target wheel has been exposed to cometary dust it is moved in front of the microscope and imaged under shallow angle illumination provided by light emitting diodes. On-board image evaluation detects the presence and location of dust particles with diameters exceeding a few micro meters and calculates their position relative to the target reference point. Once the presence of features of interest is established, the target is moved in front of the mass spectrometer. Three nanosecond duration pulses of indium-115 with an energy of 10 keV and about 10 mirco meters in diameter from the primary ion gun hit the selected feature. Secondary ions from the cometary matter are extracted by the secondary ion extraction lens (SIL) into the TOF section. After passing deflection plates for beam steering the ions travel through a field free section. Next they pass a two stage reflector, return through the drift section to the ion detector. Its main element is a single stage microsphere plate, where the ions are detected. The arrival time of each ion is measured with an accuracy of about 2 ns. Precision in the timing of the primary ion pulses, the correct selection of the dimensions and the voltages of the mass spectrometer and the accurate measurement of the secondary ion flight time are needed to obtain high mass resolution in the COSIMA instrument. A mass resolution of 2000 is achieved for ions having a flight time of 16 mirco seconds, which occurs for ion masses of above 28 Daltons (atomic mass units). Summary of COSIMA Characteristics Primary ion source Liquid metal field ion source plus ion optics producing monoisotopic beam of 115In ions, 10 keV beam energy, 10 mkm beam diameter, 3 ns duration pulses, 2000 pulses per second maximum repetition rate Secondary ion detector Microsphere plate Mass resolution (for ion masses of above 28 Da) > 2000 Mass (kg) 19.1 Dimensions (l x w x h, mm) 394 x 973 x 378 Power consumption (average, W) 20.6 Mounting Alignment -------------------------------------------------------- Refer to the latest version of the Rosetta Frames Definition Kernel (FK) [4] for the COSIMA reference frame definitions and mounting alignment information. Apparent FOV Layout -------------------------------------------------------- This section provides a diagram illustrating the COSIMA FOV layout in the COSIMA reference frame. ^ | direction of | flight | ^ +Xcosima (down-track) | | --- +---------|---------+ ^ | | | | | | | | | | | | | | | | 17.7 deg | x-------------> +Ycosima (cross-track) | | +Zcosima | | | | | | | V | | --- +-------------------+ | 32 deg | Boresight (+Z axis) |<----------------->| is into the page | | FOV Parameters -------------------------------------------------------- The following COSIMA FOV parameters are included in the data section below, from [8]: ----------------------------------------------------------------- parameter value ----------------------------------------------------------------- Field of view (deg) Cross-track 32.0 Along-track 17.7 Instantaneous field of view (deg) Cross-track 21.0 Along-track 14.0 ----------------------------------------------------------------- The keywords below provide FOV angular size in radians, with the cross-track size being the first value and the along-track size being the second value in each pair. Since each FOV is just a single pixel IFOV is equal to the FOV in size and the pixel size parameters are set accordingly. \begindata INS-226140_FOV_ANGULAR_SIZE = ( 0.55850536064, 0.3089232776 ) INS-226140_IFOV = ( 0.36651914292, 0.24434609528 ) INS-226140_PIXEL_SAMPLES = ( 32000 ) INS-226140_PIXEL_LINES = ( 10000 ) INS-226140_CCD_CENTER = ( 16000, 5000 ) \begintext FOV Definitions --------------------------------------------------------------------------- This section contains definition for the COSIMA FOV. This definition is provided in the format required by the SPICE (CSPICE) function GETFOV (getfov_c). The set of assignments in the data section below defines the COSIMA FOV with respect to the COSIMA instrument frame as a rectangle of the size provided in the section above and the boresight along the +Z axis. \begindata INS-226140_FOV_FRAME = 'ROS_COSIMA' INS-226140_FOV_SHAPE = 'RECTANGLE' INS-226140_BORESIGHT = ( 0.000000 0.000000 1.000000 ) INS-226140_FOV_CLASS_SPEC = 'ANGLES' INS-226140_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-226140_FOV_REF_ANGLE = ( 8.8500 ) INS-226140_FOV_CROSS_ANGLE = ( 17.000 ) INS-226140_FOV_ANGLE_UNITS = 'DEGREES' \begintext Platform ID --------------------------------------------------------------------------- This number is the NAIF instrument ID of the platform on which the instrument is mounted. For COSIMA this platform is the spacecraft. \begindata INS-226140_PLATFORM_ID = ( -226000 ) \begintext End of IK file.