Concept Study for an Advanced Mass and Ionic Charge Composition Experiment (AMICCE)
for Future NASA Missions, 15-R9583

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Principal Investigators
Mihir Desai
Frédéric Allegrini
Stefano Livi
David J. McComas

Inclusive Dates:  10/01/05 – 10/01/07

Background - Solar energetic particles (SEP) associated with coronal mass ejections or CMEs occur with little or no advance warning, and are often accompanied by high-energy ions that pose severe radiation hazards for humans and hardware in space. Recently, composition measurements from NASA's Advanced Composition Explorer (ACE) spacecraft have provided compelling evidence that the source material for such CME-related SEP events originates from the suprathermal tail between approximately 2 to 100 keV/nucleon rather than from the more abundant solar wind peak near approximately 1 to 2 keV/nucleon. Presently, however, properties of the suprathermal tail are not well known mainly because current solar wind instruments are relatively insensitive in the approximately 2 to 100 keV/nucleon energy range, while energetic particle instruments use solid-state detectors with high ( approximately 50 to 100 keV) lower-energy thresholds. Thus, these new findings have inspired numerous scientific investigations and competing hardware efforts to participate in a frantic race to be the first to measure and explore the uncharted suprathermal energy region. Furthermore, at present the ionic charge state and isotopic composition of the accelerated ion populations in the approximately 0.1 to 10 MeV/nucleon energy range are typically obtained by two or more large instruments on the same spacecraft. For example, SEPICA and ULEIS on ACE collectively weigh about 60 kg. However, such large instruments are highly unlikely to fly on future NASA missions.

This project will investigate the feasibility of an innovative concept for a single lightweight (less than approximately 15 kg) instrument that can measure the ionic charge state, isotopic, and elemental abundances of both the suprathermal and the energetic particle populations in the heliosphere. A single instrument that makes detailed composition measurements of the hitherto unexplored suprathermal tail between approximately 8 to 100 keV/nucleon and of the energetic ions between approximately 0.1 to 10 MeV/nucleon will provide a much-needed breakthrough in making charged particle measurements in the heliosphere. SwRI's new instrument – Advanced Mass and Ionic Charge Composition Experiment (AMICCE) – will easily meet the scientific requirements of three or more separate state-of-the-art instruments, and will therefore provide enough flexibility to remain within the stringent payload allocation for a variety of upcoming NASA and European heliospheric missions. 

Approach - The project was divided into four tasks:

  • Optimization and simulations of the electrostatic analyzer (ESA)
  • Optimization and simulations of the Time-of-Flight (TOF)
  • Design, fabrication, and testing of the ESA prototype
  • Publication of results in a scientific refereed journal

Accomplishments - The project team successfully modeled, designed, built, and tested a laboratory prototype for an innovative electrostatic analyzer (ESA) for AMICCE. The team also finished simulations and optimized the TOF section of the instrument, and designed and ordered a collimator for the ESA. Results are being organized for publication in a peer-reviewed scientific journal.

The work resulting from this internal research effort has also enabled SwRI to successfully propose for a Supporting Research and Technology (SR&T) grant from NASA to further develop the concept over a period of three years. The ESA-collimator assembly will be tested using the funding from this project. An instrument paper demonstrating the proof-of-concept in conjunction with further development work from the NASA SR&T grant will increase the technology readiness level of AMICCE and be ready for the next announcements of opportunity from NASA for future missions such as the Inner Heliospheric Sentinels.

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