Fail-safe Cold Cathode Ionizer

In response to NASAs call for development of enabling technologies for space exploration instrumentation such as mass spectrometers, Physical Sciences Inc. (PSI) is developing a novel cold cathode ionizer. The ionizer, which is being optimized for application to Heliophysics mass spectroscopy in Low Earth Orbit (LEO) combines exceptionally low power consumption, high output current densities, high reliability and an extremely compact form factor. PSIs cold cathode ionizer is also uniquely resistant to degradation by the hyperthermal atomic oxygen present in LEO. The properties render PSIs cold cathode technology uniquely suited to use near Earth, particularly those flown on cubesats and similar small spacecraft platforms. In Phase I of the development program, PSI successfully demonstrated the operating principle behind the cold cathode electron gun, yielding stable emission current densities over 60 mA/cm2 in a breadboard device. In Phase II, PSI will optimize the field emission technology while shrinking and ruggedizing the devices. The Phase II program will culminate in delivery of a flight-capable cold cathode ionizer to NASA meeting or exceeding every key performance parameter required for integration into cubesat-based mass spectrometers for Heliophysics applications. PSI is developing a cold cathode ionizer and electron gun that generates high emission currents at low voltages while drawing little more power than is contained in the beam itself. This design is therefor much more efficient than traditional thermionic electron guns. The cathode is also made of a material that is highly resistant to degradation by atomic oxygen bombardment in low Earth orbit, and it is highly miniaturized, making it uniquely suited to use in instruments for NASA programs in small satellites and close Earth. The technical objectives of the program are to demonstrate emission current densities, beam kinetic energy, operating temperature range and survivability in LEO for the ionizer. PSI will also deliver results of a study measuring the erosion rate of key materials under hyprthermal atomic oxygen bombardment simulating a LEO environment. Physical Sciences Inc. will deliver a flight-worthy, characterized cold cathode ionizer to NASA by the end of the Phase II program, as well as a test report, progress reports and a final report detailing program achievements and ionizer capabilities.
Benefits: Mass spectrometers for planetary and space environment studies, particularly the mini time-of-flight mass spectrometers being developed for Heliophysics applications. Future applications in instrumentation for outer worlds and their moons, as well as any instrument requiring high flux electron beams. Space Force personnel have expressed interest in the ionizer technology for LEO and sub-orbital mass spectrometer applications, as well as for other applications. There are also applications to electron accelerators and to x-ray generators for applications such as time and space resolved x-ray sources for medical imagers.