California Institute of Technology

James E Polk

Frank Greer

Mohammad Mehdi Mojarradi

Daniel W Wilson

Karl Y Yee

Cecile D Jung-Kubiak

Richard E Muller

Victor E White

Matthew R Dickie

Colleen M Marrese-Reading

Juergen Mueller

John R Anderson

Nima Rouhi

Colleen Marrese

Pedro P Guerrero Vela

Aspects include a method for treating a polycrystalline material, the method comprising: exposing a surface of the polycrystalline material to a plasma thereby changing the surface of the polycrystalline material from being characterized by a starting condition to being characterized by a treated condition; wherein: the surface comprises a plurality of crystallites each having the composition MB, M being a metal element; the plasma comprises ions, the ions being characterized by an average ion flux selected from the range of 1.5 to 100 A/cmand an average ion energy that is less than a sputtering threshold energy; the starting condition of the surface is characterized by a first average work function and the treated condition of the surface is characterized by a second average work function; and the second average work function is less than the first average work function.

Method and apparatus for reducing the work function of polycrystalline metal hexaboride

Micro-emitter arrays and methods of microfabricating such emitter arrays are provided. The microfabricated emitter arrays incorporate a plurality of emitters with heights greater than 280 microns with uniformity of +/&#x2212;10 microns arranged on a supporting silicon substrate, each emitter comprising an elongated body extending from the top surface of the substrate and incorporating at least one emitter tip on the distal end of the elongated body thereof. The emitters may be disposed on the substrate in an ordered array in an X by Y grid pattern, wherein X and Y can be any number greater than zero. The micro-emitter arrays may utilize a LMIS propellant source including, for example, gallium, indium, bismuth, or tin. The substrate may incorporate at least one through-via providing a fluid pathway for the LMIS propellant to flow from a propellant reservoir beneath the substrate to the top substrate surface whereupon the micro-emitter array is disposed.

Micro-emitters for electrospray systems

A micro-colloid thruster system may be fabricated using micro electromechanical system (MEMS) fabrication techniques. A beam of charged droplets may be extracted from an emitter tip in an emitter array by an extractor electrode and accelerated by an accelerator electrode to produce thrust. The micro-colloid thruster system may be used as the main propulsion system for microspacecraft and for precision maneuvers in larger spacecraft.

Micro-colloid thruster system

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Pasadena, CA, United States of America

James E Polk