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Compact electron beam focusing column

Description: A novel design for an electron beam focusing column has been developed at LBNL. The design is based on a low-energy spread multicusp plasma source which is used as a cathode for electron beam production. The focusing column is 10 mm in length. The electron beam is focused by means of electrostatic fields. The column is designed for a maximum voltage of 50 kV. Simulations of the electron trajectories have been performed by using the 2-D simulation code IGUN and EGUN. The electron temperature has also been incorporated into the simulations. The electron beam simulations, column design and fabrication will be discussed in this presentation.
Date: July 13, 2001
Creator: Persaud, Arun; Leung, Ka-Ngo & Reijonen, Jani
Partner: UNT Libraries Government Documents Department

A compact neutron generator using a field ionization source

Description: Field ionization as a means to create ions for compact and rugged neutron sources is pursued. Arrays of carbon nano-#12;bers promise the high #12;eld-enhancement factors required for efficient field ionization. We report on the fabrication of arrays of #12;field emitters with a density up to 10{sup 6} tips/cm{sup 2} and measure their performance characteristics using electron field emission. The critical issue of uniformity is discussed, as are efforts towards coating the nano-fibers to enhance their lifetime and surface properties.
Date: October 31, 2011
Creator: Persaud, Arun; Waldmann, Ole; Kapadia, Rehan; Takei, Kuniharu; Javey, Ali & Schenkel, Thomas
Partner: UNT Libraries Government Documents Department

Development of a compact neutron source based on field ionization processes

Description: The authors report on the use of carbon nanofiber nanoemitters to ionize deuterium atoms for the generation of neutrons in a deuterium-deuterium reaction in a preloaded target. Acceleration voltages in the range of 50-80 kV are used. Field emission of electrons is investigated to characterize the emitters. The experimental setup and sample preparation are described and first data of neutron production are presented. Ongoing experiments to increase neutron production yields by optimizing the field emitter geometry and surface conditions are discussed.
Date: November 25, 2010
Creator: Persaud, Arun; Allen, Ian; Dickinson, Michael R.; Schenkel, Thomas; Kapadia, Rehan; Takei, Kuniharu et al.
Partner: UNT Libraries Government Documents Department

Single ion implantation for solid state quantum computer development

Description: Several solid state quantum computer schemes are based on the manipulation of electron and nuclear spins of single donor atoms in a solid matrix. The fabrication of qubit arrays requires the placement of individual atoms with nanometer precision and high efficiency. In this article we describe first results from low dose, low energy implantations and our development of a low energy (<10 keV), single ion implantation scheme for {sup 31}P{sup q+} ions. When {sup 31}P{sup q+} ions impinge on a wafer surface, their potential energy (9.3 keV for P{sup 15+}) is released, and about 20 secondary electrons are emitted. The emission of multiple secondary electrons allows detection of each ion impact with 100% efficiency. The beam spot on target is controlled by beam focusing and collimation. Exactly one ion is implanted into a selected area avoiding a Poissonian distribution of implanted ions.
Date: December 18, 2001
Creator: Schenkel, Thomas; Meijers, Jan; Persaud, Arun; McDonald, Joseph W.; Holder, Joseph P. & Schneider, Dieter H.
Partner: UNT Libraries Government Documents Department

Device fabrication and transport measurements of FinFETs built with 28Si SOI wafers towards donor qubits in silicon

Description: We report fabrication of transistors in a FinFET geometry using isotopically purified silicon-28 -on-insulator (28-SOI) substrates. Donor electron spin coherence in natural silicon is limited by spectral diffusion due to the residual 29Si nuclear spin bath, making isotopically enriched nuclear spin-free 28Si substrates a promising candidate for forming spin quantum bit devices. The FinFET architecture is fully compatible with single-ion implant detection for donor-based qubits, and the donor spin-state readout through electrical detection of spin resonance. We describe device processing steps and discuss results on electrical transport measurements at 0.3 K.
Date: June 10, 2009
Creator: Lo, Cheuk Chi; Persaud, Arun; Dhuey, Scott; Olynick, Deirdre; Borondics, Ferenc; Martin, Michael C. et al.
Partner: UNT Libraries Government Documents Department