KPL/IK FREND Instrument Kernel =============================================================================== This instrument kernel (I-kernel) contains the ExoMars-2016 Trace Gas Orbiter (TGO) Fine Resolution Epithermal Neutron Detector (FREND) instrument geometric parameters and field-of-view (FOV) definitions. Version and Date ------------------------------------------------------------------------------- Version 0.6 -- April 9, 2021 -- Ricardo Valles Blanco, ESAC/ESA Fixed typos for PDS4 Bundle release Version 2.0, and updated contact information. Version 0.5 -- July 20, 2017 -- Marc Costa Sitja, ESAC/ESA Updated FoV reference angle and minor typos. Version 0.4 -- September 26, 2016 -- Marc Costa Sitja, ESAC/ESA After FREND review in the ExoMars 2016 SWT #11 only one FOV is required. FREND 3He detectors (TGO_FREND_HE) and FREND stilbene scintillator detector (TGO_FREND_SC) definitions have been removed and FREND full (TGO_FREND) has been renamed to FREND detectors. The INS-143210_PLATFORM_ID INS-143220_PLATFORM_ID ids have also been removed. Version 0.3 -- August 2, 2016 -- Marc Costa Sitja, ESAC/ESA Corrected minor typos. Preliminary version. Pending review by the FREND instrument team. Version 0.2 -- May 24, 2016 -- Jorge Diaz del Rio, ODC Space Corrected TGO_FREND_SC frame definition. Preliminary version. Pending review by the TGO Science Operations and by the FREND instrument team. Version 0.1 -- May 19, 2016 -- Jorge Diaz del Rio, ODC Space Added instrument description. Added TGO_FREND Full FoV definition. Corrected TGO_FREND_HE and TGO_FREND_SC reference frame values. Preliminary version. Pending review by the TGO Science Operations and by the FREND instrument team. Version 0.0 -- September 21, 2015 -- Anton Ledkov, IKI Initial Release. References ------------------------------------------------------------------------------- 1. ``Kernel Pool Required Reading'' 2. ExoMars-2016 Frames Definition Kernel (FK), latest version. 3. http://l503.iki.rssi.ru/FREND-en.html 4. ``FREND Mechanical ICD Drawings,'' EXM-FR-DRW-IKI-0020, Issue 1.2, 1 March 2015 Contact Information ------------------------------------------------------------------------------- If you have any questions regarding this file contact SPICE support at ESA: Alfredo Escalante Lopez (+34) 91-8131-429 spice@sciops.esa.int or SPICE support at IKI: Anton Ledkov +7 (495) 333-12-66 aledkov@rssi.ru or NAIF at JPL: Boris Semenov +1 (818) 354-8136 Boris.Semenov@jpl.nasa.gov Implementation Notes ------------------------------------------------------------------------------- Applications that need SPICE I-kernel data must ``load'' the I-kernel file, normally during program initialization. The SPICE routine FURNSH loads a kernel file into the pool as shown below. CALL FURNSH ( 'frame_kernel_name' ) -- FORTRAN furnsh_c ( "frame_kernel_name" ); -- C cspice_furnsh, frame_kernel_name -- IDL cspice_furnsh( 'frame_kernel_name' ) -- MATLAB furnsh( frame_kernel_name ) -- PYTHON* 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''. Once the file has been loaded, the SPICE routine GETFOV (getfov_c in C, cspice_getfov in IDL and MATLAB and cspice.getfov in PYTHON) can be used to retrieve FOV parameters for a given instrument or structure. The application program may obtain the value(s) for any other IK data item using the SPICELIB routines GDPOOL, GIPOOL, GCPOOL (gdpool_c, gipool_c, gcpool_c in C, cspice_gdpool, cspice_gipool, cspice_gcpool in IDL and MATLAB, cspice.gcpool in PYTHON). See [2] for details. This file was created with, and can be updated with a text editor or word processor. * SPICEYPY is a non-official, community developed Python wrapper for the NAIF SPICE toolkit. Its development is managed on Github. It is available at: https://github.com/AndrewAnnex/SpiceyPy Naming Conventions and 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 TGO instrument ID code, constructed using the spacecraft ID number (-143) followed by the NAIF three digit ID number for FREND module. These IDs are defined in [2] as follows: Name NAIF ID --------------------- --------- TGO_FREND -143200 The remainder of the keyword name is an underscore character followed by the unique name of the data item. For example, the FREND stilbene scintillator detector boresight direction in the TGO_FREND frame is specified by: INS-143200_BORESIGHT The upper bound on the length of the name of any data item is 32 characters. If the same item is included in more than one file, or if the same item appears more than once within a single file, the latest value supersedes any earlier values. Instrument Description ------------------------------------------------------------------------------- FREND contains four 3He counters for neutrons with energies from 0.4 keV to 500 keV, and stilbene-based scintillator for high-energy neutrons (up to 10 MeV) (see [3]). All of them have a narrow field of view (FOV) with a pixel size corresponding to 40 km on the Martian surface. The instrument also includes a dosimetry module, which will constantly monitor the radiation environment while in orbit around the planet. The 3He detectors are proportional counters filled with helium-3 under a pressure of 6 atmospheres and placed inside four openings of the collimator. Each of them counts neutrons independently, such that the count statistics is higher (and, thus, maps are statistically more reliable) and the instrument is more resistant to failures. These detectors measure neutrons with energies ranging from 0.4 to 500 keV. The Scintillation counter, which uses stilbene crystal, measures fast neutrons with energies between 0.5-10 MeV. The counter is placed inside the collimator. Scintillation module includes an anti-coincidence shielding, to discriminate between signals from high-energy charged particles and neutrons. FREND's collimation module is a passive element, encasing all five detectors. The collimator consists of two layers, the outer one made of high-density polyethylene, the inner one of enriched boron powder (B10). Neutrons, hitting the collimator's sides, are slowed down by polyethylene, with a large number of hydrogen atoms. So thermalized neutrons then pass through and get into the B10 layer, which absorbs them. The collimator's opening angle narrows FOV of the detectors to the spot with a diameter of 40 km on the Martian surface, when seen from the circular orbit with 400 km altitude -which is the one allocated for TGO-. The Liulin-MO dosimetry module's detection system consists of two telescopes with 2 semiconductor detectors (effective area of 2 cm2) each. The Dosimeter's energy resolution is not lower than 100 keV in 100keV - 8MeV energy release range (in the detector) and not lower than 350 keV in a 8 - 70 MeV range. Mounting Alignment ------------------------------------------------------------------------------- Refer to the latest version of the ExoMars-2016 Frames Definition Kernel (FK) [2] for the FREND reference frame definitions and mounting alignment information. FREND Detectors Layout ------------------------------------------------------------------------------- This section provides an overview of the FREND 3He and stilbene scintillation detectors layout and the location of the dosimetry module with respect to the detectors. The drawings have been taken from [4]. -Y FREND side (spacecraft science deck) view: --------------------------------------------- +Ysc .-----------. x---------> | Dosimeter | | +Zsc | | | .---------------------------------------------. | | _____________________________ | | +Xsc | .' '. | v | .' . --- . . --- . '. | | / / \ / \ \ | | . . . . . . | | | | | | | | | | | . . . . | | | | \ / \ / | | | | . ___ . . - . . ___ . | | | | / \ +Zfrend | | | | +Yfrend x---------> | | | | \ | / | | | | . --- . . | . . --- . | | | | / \ | / \ | | | | . . | . . | | | | | | v | | | | | . . . +Xfrend . . | | \ \ / \ / / | | . . ___ . . ___ . . | | '. .' | | '---------------------------' | '---------------------------------------------' +Ysc and +Yfrend are into the page. +Z FREND side view: ------------------- \\ __________________// .--------------------| \\ | Dosimeter | Electrical Connectors | .---------------------------'------------------\\ v | // ------- '----------__________ \\ """"""""""...........___ // 15 deg FoV | A | \\ __________..........'''''''''''---' // ------- ."""""""""" \\ ^ | // | '"""""""""""""""""""""_________ +Zfrend +Yfrend | o-------------> | _____________________""""""""""'--|-B // v | | \\ ------- '----------__________ | +Xfrend // """"""""""....v......___ \\ 15 deg FoV | A | // __________..........'''''''''''---' \\ ------- ."""""""""" // ^ | \\ | '----------------------------------------------// \\ +Zsc +Ysc o---------> | A: 3He Counter | B: Scintillator | v +Xsc +Zsc and +Zfrend are out of the page. FOV Definitions -------------------------------------------------------- The FREND Detectors Field of view is defined based on the shape of the detectors aperture in the -Y instrument side, and the distance to detector along this axis from the aperture, corresponding to a circular field of view with a half cone of 7.5 degrees (see [4], NR26-1). The instrument and detectors boresight is along the -Y TGO_FREND axis pointing --nominally-- towards the s/c nadir direction. This section contains an assignment defining the FREND FOV. This definition is based on the FREND detector layout provided in the previous section and are provided in a format consistent with/required by the SPICE TOOLKIT function GETFOV. FREND detectors (TGO_FREND) FoV: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The FoV definitions correspond to the NAIF Body Name: TGO_FREND. \begindata INS-143200_NAME = 'TGO_FREND' INS-143200_BORESIGHT = ( 0.000000 -1.000000 0.000000 ) INS-143200_FOV_FRAME = 'TGO_FREND' INS-143200_FOV_SHAPE = 'CIRCLE' INS-143200_FOV_CLASS_SPEC = 'ANGLES' INS-143200_FOV_REF_VECTOR = ( 1.000000 0.000000 0.000000 ) INS-143200_FOV_REF_ANGLE = ( 7.50000 ) INS-143200_FOV_ANGLE_UNITS = 'DEGREES' \begintext Platform ID ------------------------------------------------------------------------------- This number is the NAIF instrument ID of the platform on which the sensors are mounted. For the Fine Resolution Epithermal Neutron Detector (FREND) platform is spacecraft. Please refer to the latest version of the ExoMars-2016 NAIF ID Codes Definitions [3] for mapping of ID codes to sensor and structure names. \begindata INS-143200_PLATFORM_ID = ( -143000 ) \begintext End of IK File.