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Laboratory for Atmospheric and Space Physics


HILT (Heavy Ion large Area Proportional Counter Telescope for Solar and Anomalous Cosmic Rays)

The HILT sensor is designed to measure heavy ions from He to Fe in the energy range from 8 to 220 MeV/nucleon for oxygen, covering the medium-energy solar energetic ions, galactic cosmic rays, and the range of maximum intensity of the anomalous cosmic ray component. The sensor consists of a three-element ion drift chamber with two thin multi-layer entrance windows followed by an array of 16 solid state detectors and a scintillation counter with photodiodes. The HILT instrument uses a flow-through isobutane system for the drift chamber. The fluid isobutane tank in SAMPEX is located with its longitudinal axis on the spin axis of the payload. The tank is 40.6 cm long by 24.1 cm in diameter with a volume of 1.5 x 104 cm3. At launch the tank was approximately 90% filled with isobutane fluid.

Detailed description of the HILT instrument

LICA (Low Energy Ion Compositon Analyzer)

Low Energy Ion Compositon Analyzer:
The SAMPEX LICA instrument is designed to measure ~0.5–5 MeV/nucleon solar and magnetospheric ions over the range from He–Ni. The instrument is time-of-flight mass spectrometer which measures particle time-of-flight over a ~0.5 m path, and the residual energy deposited in an array of Si solid state detectors. Large area microchannel plates are used, resulting in a large geometrical factor for the instrument (0.8 cm2 sr) which is essential for accurate compositional measurements in small solar flares, and in studies of precipitating magnetospheric heavy ions.

Detailed description of the LICA instrument

MAST (Mass Spectrometer Telescope)

MAST is designed to measure the isotopic composition of elements from Li (Z=3) to Ni (Z=283 in the range from approximately 10 MeV/nucleon to several hundred MeV/nucleon. MAST consists of a combination of surface barrier and lithium-drifted solid-state detectors (11 total). Combined matrix detector positions determine the particle trajectories, allowing accurate corrections to be made for the path length variation with angle and detector response non-uniformities. Although optimized for isotopic analysis of the elements Li to Ni, MAST also performs measurements of stopping He isotopes from approximately 7 to 20 MeV/nucleon. In addition, MAST analyzes particles that penetrate the entire stack, providing differential energy spectra of the more abundant elements to well beyond the endpoint energy for stopping particles, and integral flux measurements at higher energies. A priority system ensures that the most interesting events are selected for readout, with stopping Z >= 3 events given the highest priority. However, because MAST is assigned a high telemetry data rate, the pulse heights from essentially all stopping Z >= 3 nuclei can be transmitted, even in very large flares.

Detailed description of the MAST instrument

PET (Proton/Electron Telescope)

The PET system is designed to complement MAST by measuring the energy spectra and relative composition of protons (18 to 250 MeV) and helium nuclei (18 to 350 MeV/nuclei) of solar, interplanetary, and galactic origins, and the energy spectra of solar flare and precipitating electrons from approximately 0.4 to ~30 MeV. The instrument measures both trapped and precipitating energetic particles in different parts of the SAMPEX orbit. It also has the capability to look at man-made particle populations such as positrons which are emitted by nuclear reactors that have flown previously in low-Earth orbit. The PET system can also duplicate and extend some measurement capabilities of MAST by providing energy spectra and elemental composition of nuclei from Li through Fe using a commandable high-gain mode. It provides some isotopic information on nuclei from H to Ne.

Detailed description of the PET instrument


Data Processing Unit provides overall control of the scientific payload while acquiring, combining, and compressing science data to produce the science telemetry for the mission.

Detailed description of the DPU