HYPERBOLOID is a plasma spectrometer aimed at the investigation of the low energy ions dynamics in the high latitude ionosphere and magnetosphere on the INTERBALL Auroral Probe. It is a multi-directional ion mass spectrometer measuring 3D ion distribution functions over an energy range from about 0.1 to 80 eV. In normal modes of operation, the four major species H+, He+, O+ and O++ can be measured simultaneously. Special modes may be used to detect minor species such as N+ or the molecular ions. Angular and energy distributions are obtained by means of an electrostatic optics constituted of two analyzers, each of which measures ions with velocities in a half-plane. The main analyzer encompasses 16 windows at 10° intervals with individual FOV about 12° and effective entrance area about 0.8 cm^2. Its half-plane contains the spacecraft spin axis so that the instrument is able to sample practically the full space in a complete spin period (120 s). Depending on the number of windows simultaneously opened, the angular resolution can be varied from 10° to 40°, thus providing an adjustable trade off between angular and time resolution. The secondary analyzer has its half-plane almost orthogonal to the main one, with 10 windows at 15° intervals, FOV about 5° and effective entrance area about 5 to 8 times less than in the main plane. Again, from 1 to 4 windows can be activated simultaneously. This second analyzer provides partial access to the 3D features of the distributions with a much better time resolution (typically a few seconds), thus enabling to look at fast plasma variations.
Each window is followed by a spherical electrostatic energy analyzer. The nominal energy resolution is about +/-10% for the main analyzer and +/-5% for the secondary one. By pre-accelerating or decelerating the ions at the entrance of the energy analyzer, one can vary this resolution by a factor between about 0.5 and 2.
An arrangement of 2 toroidal concentrators is used to focus ions at the entrance of a magnet (which provides the mass separation), irrespective of their direction of arrival. There are 4 identical MCP detectors in the focal plane, one for each of the major ions. Depending on the ion flux they can be operated either in digital (pulse counting) or in analog (charge integration) mode, thus providing a total dynamic range of 10^11.
The temporal resolution of the instrument for a complete angular and energy scan depends on the telemetry rate and varies between 1 and 16 s.
During the first few months of operations, an ion beam emitter (RON experiment, PI K. Torkar, SRI, Graz, Austria) was used to maintain Interball Auroral potential at low positive values. During periods without active potential control, the satellite potential typically varies between 0 and +6 or +8 Volts. A -8 V potential bias is applied to Hyperboloid entrance, so that in most cases the full thermal ion distributions can be measured.
Version:2.4.0
HYPERBOLOID is a plasma spectrometer aimed at the investigation of the low energy ions dynamics in the high latitude ionosphere and magnetosphere on the INTERBALL Auroral Probe. It is a multi-directional ion mass spectrometer measuring 3D ion distribution functions over an energy range from about 0.1 to 80 eV. In normal modes of operation, the four major species H+, He+, O+ and O++ can be measured simultaneously. Special modes may be used to detect minor species such as N+ or the molecular ions. Angular and energy distributions are obtained by means of an electrostatic optics constituted of two analyzers, each of which measures ions with velocities in a half-plane. The main analyzer encompasses 16 windows at 10° intervals with individual FOV about 12° and effective entrance area about 0.8 cm^2. Its half-plane contains the spacecraft spin axis so that the instrument is able to sample practically the full space in a complete spin period (120 s). Depending on the number of windows simultaneously opened, the angular resolution can be varied from 10° to 40°, thus providing an adjustable trade off between angular and time resolution. The secondary analyzer has its half-plane almost orthogonal to the main one, with 10 windows at 15° intervals, FOV about 5° and effective entrance area about 5 to 8 times less than in the main plane. Again, from 1 to 4 windows can be activated simultaneously. This second analyzer provides partial access to the 3D features of the distributions with a much better time resolution (typically a few seconds), thus enabling to look at fast plasma variations.
Each window is followed by a spherical electrostatic energy analyzer. The nominal energy resolution is about +/-10% for the main analyzer and +/-5% for the secondary one. By pre-accelerating or decelerating the ions at the entrance of the energy analyzer, one can vary this resolution by a factor between about 0.5 and 2.
An arrangement of 2 toroidal concentrators is used to focus ions at the entrance of a magnet (which provides the mass separation), irrespective of their direction of arrival. There are 4 identical MCP detectors in the focal plane, one for each of the major ions. Depending on the ion flux they can be operated either in digital (pulse counting) or in analog (charge integration) mode, thus providing a total dynamic range of 10^11.
The temporal resolution of the instrument for a complete angular and energy scan depends on the telemetry rate and varies between 1 and 16 s.
During the first few months of operations, an ion beam emitter (RON experiment, PI K. Torkar, SRI, Graz, Austria) was used to maintain Interball Auroral potential at low positive values. During periods without active potential control, the satellite potential typically varies between 0 and +6 or +8 Volts. A -8 V potential bias is applied to Hyperboloid entrance, so that in most cases the full thermal ion distributions can be measured.
| Role | Person | StartDate | StopDate | Note | |
|---|---|---|---|---|---|
| 1. | CoInvestigator | spase://CNES/Person/CDPP-Archive/Nicolas.Dubouloz | |||
| 2. | FormerPI | spase://CNES/Person/CDPP-Archive/Jean-Jacques.Berthelier |