Editing Advanced Composition Explorer (section)

=== Solar Isotope Spectrometer (SIS) ===
[[File:ACE-sis sm.jpg|thumb|SIS]]
The Solar Isotope Spectrometer (SIS) provides high-resolution measurements of the isotopic composition of energetic nuclei from He to Zn (Z=2 to 30) over the energy range from ~10 to ~100 MeV/nucleon. During large solar events, SIS measures the isotopic abundances of solar energetic particles to determine directly the composition of the [[solar corona]] and to study particle acceleration processes. During solar quiet times, SIS measures the isotopes of low-energy cosmic rays from the Galaxy and isotopes of the anomalous [[cosmic ray]] component, which originates in the nearby interstellar medium. SIS has two telescopes composed of silicon solid-state detectors that provide measurements of the nuclear charge, mass, and kinetic energy of incident nuclei. Within each telescope, particle trajectories are measured with a pair of two-dimensional silicon strip detectors instrumented with custom very-large-scale integrated (VLSI) electronics to provide both position and energy-loss measurements. SIS was specially designed to achieve excellent mass resolution under the extreme, high flux conditions encountered in large solar particle events. It provides a geometry factor of 40&nbsp;cm<sup>2</sup> sr, significantly greater than earlier solar particle isotope spectrometers.<ref name=stone98c>{{cite journal |last=Stone |first=E. C. |title=The Solar Isotope Spectrometer for the Advanced Composition Explorer |journal=Space Science Reviews |date=July 1998 |volume=86 |pages=357–408 |doi=10.1023/A:1005027929871 |bibcode=1998SSRv...86..357S |s2cid=16609619 |display-authors=et al.}}</ref>