The electron field-emission properties of carbon nanotubes enable the fabrication of cold cathodes for a variety of vacuum device applications. The utilization of these cathodes is an attractive alternative for the replacement of thermionic or hot cathodes for generating X-rays. Miniature X-ray tubes have been fabricated using triode-style carbon nanotubebased cathodes. In this paper we report ...

The 3D finite-element gun and collector modeling code, MICHELLE, has been under development at SAIC in collaboration with industrial partners and national laboratories (ref. 1). This development program has been designed to address the shortcomings of current beam optics simulation and modeling tools for vacuum electron devices. The program specifically targets problem classes including gridded...

Understanding how the interactions between a chromophore and its surrounding protein control the function of a photoactive protein remains a challenge. Here, we present the results of photoelectron spectroscopy measurements and quantum chemistry calculations aimed at investigating how substitution at the coumaryl tail of the photoactive yellow protein chromophore controls competing relaxation p...

High average power FELs require high average current electron injectors capable of generating high quality, short duration electron bunches with a repetition rate equal to the frequency of the rf linac. In this paper we propose, analyze and simulate an rf-gated, gridded thermionic electron gun for use in high average power FELs. Thermionic cathodes can provide the necessary high current, have l...

A photoelectron spectroscopy study of the anionic model chromophore of the green fluorescent protein is presented. From the photoelectron spectra taken at 3.496 eV, 4.62 eV, and 6.15 eV the vertical and adiabatic detachment energies are determined to be 2.8 ± 0.1 eV and 2.6 ± 0.2 eV, respectively. The vertical detachment energy is higher than the S1← S0 absorption maximum (2.57 eV) and indicate...

0167-9317/$ see front matter 2009 Elsevier B.V. A doi:10.1016/j.mee.2009.03.123 q This paper was presented in MNE 2008 c www.mne-conf.org. * Corresponding author. Address: Department of E neering, Imperial College London, South Kensington C Tel.: +44 207 5946232. E-mail address: [email protected] (Z.A.K. D 1 JSPS Fellow. Si nanocrystals and nanochains, prepared by material synthesis, pro...

Material models which incorporate the basic characteristics of the underlying physics in a given semiconductor material are the core of device modeling. We employ a Monte Carlo (MC) technique to investigate stationary electron transport in GaN and AlGaN [1]. We obtain a set of model parameters which gives agreement with experimental data available for different physical conditions (doping, temp...