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Mass spectrometry is one of the most powerful techniques that allows qualitative and quantitative characterization of chemical compounds. However, bulky high vacuum system required for analysis process limits application to professional laboratories. These restrictions can be overcome by replacing them with miniature high vacuum MEMS (Micro-Electro-Mechanical System). Our group, as the first in the...
We report on the transition from field electron emission to plasma discharges. During an experiment with a miniaturized field emission electron source a plasma discharge accompanied by a luminous effect was observed. A novel graphical evaluation method was used to interpret and to compare the observed phenomenon.
For the realization of a miniaturized field emission electron source we tested benzocyclobutene (BCB) as a new spacer material between cathode and anode. We fabricated black silicon emitters and characterized the emission behavior with an integrated 5 μm thin and large-area spacer of BCB. The integrated BCB layer allows the realization of a compact electron source with only two components consisting...
We present our work on the development and characterization of a practical and robust LaB6 based cold field emitter electron source. To this end we prepared a Tantalum mounted single crystal LaB6 rod that was chemically etched, yielding an apex size of 2μm. The obtained tip is loaded into a ultra high vacuum chamber for pulsed emission in the μs regime, using extraction voltage pulsing. Further processing...
Ion mobility spectrometers (IMS) are measurement devices for fast and ultra-sensitive trace gas analysis. Most IMS employ radioactive electron sources, such as 3H or 63Ni, to provide free electrons with high kinetic energy at atmospheric pressure for initiating a chemical gas phase ionization of the analytes. The disadvantage of these radioactive materials are legal restrictions and the electron emission...
The institute of aerospace engineering at TU Dresden is developing a highly miniaturized field emission electric propulsion (FEEP) system for Nano-satellites, called CubeSats. The presented propulsion system NanoFEEP is composed of the actual field emission thrusters and a carbon nanotubes silicon chip used as a cold electron source for neutralizing the electric charging behavior of the spacecraft...
A control circuit to stabilize the flux of electrons transmitted through an extractor electrode is presented. By controlling the emission current a fluctuation with a standard deviation of 0.015% is observed. However, the achievable stability of the transmitted electron current is limited due to a variation of the extraction grid current ratio showing a standard deviation of 4.33%. By regulating the...
We fabricated field emission electron sources and applied for the glass sealed x-ray tube for medical imaging devices. The x-ray tube consists of an electron beam with a patterned grown CNT emitters with RAP process. Those electron beam shows higher electron emission current and transmittance after glass seal. With the x-ray tube, we success to measure medical image with finger and high resolution...
We fabricated high resolution electron beam with carbon nanotube cold cathode for microscopy application. The electron beam shows a resolution of 165 μm with phosphor light area measurement and higher emission current more than 60 μA. The electron beam has 9 individual electron sources with CNTs. The electron emission current depend on the length and pitches between CNT emitters. The isolated individual...
The purpose of the present work is to study anticorrelation between quantum efficiency and spin-polarization, which is a characteristic feature of GaAs photocathodes. We employ the Monte Carlo techniques to simulate in detail the photo-absorption, electron transport, and tunnelling of electrons through the potential barrier at the surface of p-doped GaAs activated to negative electron affinity (NEA)...
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