Particles enter the IMAP-LoThe IMAP-Lo instrument collects, counts, categorizes, and maps interstellar neutral atoms (ISN) and energetic neutral atoms (ENAs) of energies less than 40 kiloelectron volts (keV). IMAP-Lo is mounted on a pivot platform that allows it to adjust its field-of-view to capture data across almost the entire sky, and to measure interstellar neutral atoms throughout most of the year. instrument through the ring-shaped collimatorA device at the entrance to a sensor instrument that narrows a beam of particles or waves, such as light or energetic neutral atoms, into a more parallel or aligned stream. This helps improve the precision and accuracy of measurements or imaging by reducing the spread of the beam; the “gateway” into a sensor. into the sensor head that includes the electrical systems. The collimator only lets particles from a narrow range of directions pass through it. Directionality for mapping the particles coming from the heliosphereThe bubble-like region surrounding the solar system inflated by the solar wind, shielding the solar system from interstellar radiation. and the nearby interstellar mediumThe interstellar medium is the matter that exists in the space between the stars within a galaxy. This matter includes ionized and electrically neutral gas (primarily hydrogen and helium), dust, and cosmic rays. The ISM plays a crucial role in the lifecycle of stars and galaxies. It is the reservoir from which new stars are born and into which old stars expel material when they die. is determined by where in the sky the instrument is facing. Mounted on a pivot platform, the IMAP-Lo’s field-of-viewThe area or region that can be observed or captured by a particular instrument or sensor. can be adjusted remotely to collect data over nearly 100% of the sky.

An electrified deflector shield surrounds the entire sensor head and prevents low-energy charged solar particles from entering the collimator. The collimator directs the incoming particles towards an electrified surface made of a special material that converts the neutral particles into negatively charged ions. A ring of magnets is also used to deflect electrons out of the way.

The newly charged ions are funneled into an electrostatic energy analyzer, or ESAAn Electrostatic Analyzer is an instrument used in ion optics that employs an electric field to allow the passage of only those ions or electrons that have a given specific energy. It usually also focuses these particles (concentrates them) into a smaller area.. This part of the instrument consists of two electrically charged plates that allow only ions of specific energy levels to be passed through the analyzer’s uniquely shaped channel and towards the next sensor. Ions that are too high of an energy crash into the outer plate of the channel, ions with too low of energy crash into the inner plate of the channel.

The ions that fall into that specific energy range, or passband, then reach the timeA measure of the flow of events.-of-flight (ToF) sensor. The ToF sensor uses the time needed for an ionAn atom that has become electrically charged by the gain or loss of one or more electrons. to travel between two foil surfaces. Scientists can use this timing of particles at a specific passband energy to determine the velocity of the particle. The combination of velocity and energy determine what type of particle it is, such as whether it is helium, oxygen, or hydrogen.

Learn more about imap-Lo

Using the energy levels of the converted ISN and ENA particles and the direction they entered IMAP’s collimatorA device at the entrance to a sensor instrument that narrows a beam of particles or waves, such as light or energetic neutral atoms, into a more parallel or aligned stream. This helps improve the precision and accuracy of measurements or imaging by reducing the spread of the beam; the “gateway” into a sensor., scientists can create a map using color-coded pixels that shows the origin of the different particles from the heliosphereThe bubble-like region surrounding the solar system inflated by the solar wind, shielding the solar system from interstellar radiation., as well as their energetic levels. Using the ToF sensor data, scientists like IMAP-LoThe IMAP-Lo instrument collects, counts, categorizes, and maps interstellar neutral atoms (ISN) and energetic neutral atoms (ENAs) of energies less than 40 kiloelectron volts (keV). IMAP-Lo is mounted on a pivot platform that allows it to adjust its field-of-view to capture data across almost the entire sky, and to measure interstellar neutral atoms throughout most of the year. lead Nathan Schwadron can also map the type, or species, of particle, helping us to understand better the compositionThe specific components or “ingredients” that make up a substance or type of matter. of the heliosphere protecting our solar neighborhood, as well as the composition and flow direction of the interstellar mediumThe interstellar medium is the matter that exists in the space between the stars within a galaxy. This matter includes ionized and electrically neutral gas (primarily hydrogen and helium), dust, and cosmic rays. The ISM plays a crucial role in the lifecycle of stars and galaxies. It is the reservoir from which new stars are born and into which old stars expel material when they die. where the two entities interact with each other.

Meet the Team

The IMAP-Lo instrument was built at University of New Hampshire in Durham, New Hampshire. The team is led by Nathan Schwadron, who also serves as a deputy Principal Investigator for the IMAP mission. The IMAP-Lo team also has collaborators from Southwest Research Institute (SwRI) in San Antonino, TX, the University of Bern, Bern, Switzerland, Princeton University in Princeton, NJ, and Johns Hopkins University APL in Laurel, MD. The pivot platform for IMAP-Lo was built by the Sierrra Space Aerospace Company and is managed by the Johns Hopkins University APL. 

The extreme efforts put forth by the team at SwRI to overcome many design challenges to get one of the most technically complicated parts of the instrument, the Conversion Surface and ESAAn Electrostatic Analyzer is an instrument used in ion optics that employs an electric field to allow the passage of only those ions or electrons that have a given specific energy. It usually also focuses these particles (concentrates them) into a smaller area., done on schedule was nothing short of a triumph. 

- David Heirtzler, System Engineer, IMAP-Lo