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A SPICE Model and Electrostatic Field Analysis of the MOS Turn-Off Thyristor

Description: This paper presents a circuit model and an electrostatic field analysis with an approximate model of the SDM170HK MOS turn-off thyristor (MTO) fabricated by Silicon Power Corporation. The circuit model consists of five cells, each containing two bipolar junction transistors and three resistors. The turn-off feature of the MTO was simulated by inserting an array of 21 Fairchild FDS6670A MOSFET importable sub-circuit components between the cathode and the turn-on gate. The model was then used to … more
Date: August 5, 2002
Creator: Kelly, D. Q.; Mayhall, D. J.; Wilson, M. J. & Lahowe, D. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A new time-dependent analytic model for radiation-induced photocurrent in finite 1D epitaxial diodes.

Description: Photocurrent generated by ionizing radiation represents a threat to microelectronics in radiation environments. Circuit simulation tools such as SPICE [1] can be used to analyze these threats, and typically rely on compact models for individual electrical components such as transistors and diodes. Compact models consist of a handful of differential and/or algebraic equations, and are derived by making simplifying assumptions to any of the many semiconductor transport equations. Historically, ma… more
Date: April 1, 2012
Creator: Verley, Jason C.; Axness, Carl L.; Hembree, Charles Edward; Keiter, Eric Richard & Kerr, Bert (New Mexico Institute of Mining and Technology, Socorro, NM)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Simulation Studies of the X-Ray Free-Electron Laser Oscillator

Description: Simulations of the x-ray free-electron laser (FEL) oscillator are presented that include transverse effects and realistic Bragg crystal properties with the two-dimensional code GINGER. In the present cases considered the radiation divergence is much narrower than the crystal acceptance, and the numerical algorithm can be simplified by ignoring the finite angular bandwidth of the crystal. In this regime GINGER shows that the saturated x-ray pulses have 109 photons and are nearly Fourier-limited … more
Date: August 14, 2009
Creator: Lindberg, R. R.; Shyd'ko, Y.; Kim, K. J. & Fawley, W. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Evaluate Status of Pacific Lamprey in the Clearwater River Drainage, Idaho, Annual Report 2002.

Description: In 2002 Idaho Department of Fish and Game continued investigation into the status of Pacific lamprey populations in Idaho's Clearwater River drainage. Trapping, electrofishing, and spawning ground redd surveys were used to determine Pacific lamprey distribution, life history strategies, and habitat requirements in the South Fork Clearwater River, Lochsa River, Selway River, and Middle Fork Clearwater River subbasins. Five-hundred forty-one ammocoetes were captured electroshocking 70 sites in th… more
Date: October 1, 2003
Creator: Cochnauer, Tim & Claire, Christopher
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

An Enhanced GINGERSimulation Code with Harmonic Emission and HDF5IO Capabilities

Description: GINGER [1] is an axisymmetric, polychromatic (r-z-t) FEL simulation code originally developed in the mid-1980's to model the performance of single-pass amplifiers. Over the past 15 years GINGER's capabilities have been extended to include more complicated configurations such as undulators with drift spaces, dispersive sections, and vacuum chamber wakefield effects; multi-pass oscillators; and multi-stage harmonic cascades. Its coding base has been tuned to permit running effectively on platform… more
Date: September 1, 2006
Creator: Fawley, William M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Tunable Soft X-Ray Oscillators

Description: A concept for a tunable soft x-ray free electron laser (FEL) photon source is presented and studied numerically. The concept is based on echo-enabled harmonic generation (EEHG), wherein two modulator-chicane sections impose high harmonic structure with much greater efficacy as compared to conventional high harmonic FELs that use only one modulator-chicane section. The idea proposed here is to replace the external laser power sources in the EEHG modulators with FEL oscillators, and to combine th… more
Date: September 17, 2010
Creator: Wurtele, Jonathan; Gandhi, Punut; Gu, X-W; Fawley, William M; Reinsch, Matthia; Penn, Gregory et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

XFEL Oscillator Simulation Including Angle-Dependent Crystal Reflectivity

Description: The oscillator package within the GINGER FEL simulation code has now been extended to include angle-dependent reflectivity properties of Bragg crystals. Previously, the package was modified to include frequencydependent reflectivity in order to model x-ray FEL oscillators from start-up from shot noise through to saturation. We present a summary of the algorithms used for modeling the crystal reflectivity and radiation propagation outside the undulator, discussing various numerical issues releva… more
Date: August 23, 2010
Creator: Fawley, William; Lindberg, Ryan; Kim, K. J. & Shvyd'ko, Yuri
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

LCLS X-Ray FEL Output Performance in the Presence of HighlyTime-Dependent Undulator Wakefields

Description: Energy loss due to wakefields within a long undulator, if not compensated by an appropriate tapering of the magnetic field strength, can degrade the FEL process by detuning the resonant FEL frequency. The wakefields arise from the vacuum chamber wall resistivity, its surface roughness, and abrupt changes in its aperture. For LCLS parameters, the resistive-wall component is the most critical and depends upon the chamber material (e.g., Cu) and its radius. Of recent interest[1] is the so-called '… more
Date: August 25, 2005
Creator: Bane, Karl L. F.; Emma, Paul; Huang, Heinz-Dieter Nuhn; Stupakov, Gennady; Fawley, William M. & Reiche, Sven
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Simulation studies of a XUV/soft X-ray harmonic-cascade FEL for the proposed LBNL recirculating linac*

Description: Presently there is significant interest at LBNL in designing and building a facility for ultrafast (i.e. femtosecond time scale) x-ray science based upon a superconducting, recirculating RF linac (see Corlett et al. for more details). In addition to producing synchrotron radiation pulses in the 1-15 keV energy range, we are also considering adding one or more free-electron laser (FEL) beamlines using a harmonic cascade approach to produce coherent XUV soft X-ray emission beginning with a strong… more
Date: June 2, 2003
Creator: Fawley, W. M.; Barletta, W. A.; Corlett, J. N. & Zholents, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Observations of z-dependent microbunching harmonic intensities using COTR in a SASE FEL.

Description: The nonlinear generation of harmonics in a self-amplified spontaneous emission (SASE) free-electron laser (FEL) continues to be of interest. Complementary to such studies is the search for information on the electron beam microbunching harmonic components, which are revealed by coherent optical transition radiation (COTR) experiments. An initial z-dependent set of data has been obtained with the fundamental at 530 nm and the second harmonic at 265 nm. The latter data were collected after every … more
Date: September 24, 2002
Creator: Lumpkin, A. H.; Biedron, S. G.; Dejus, R. J.; Berg, W. J.; Borland, M.; Chae, Y. C. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Harmonic cascade FEL designs for LUX

Description: LUX is a design concept for an ultrafast X-ray science facility, based on an electron beam accelerated to GeV energies in are circulating linac. Included in the design are short duration (200 fs or shorter FWHM) light sources using multiple stages of higher harmonic generation, seeded by a 200-250 nm laser of similar duration. This laser modulates the energy of a group of electrons within the electron bunch; this section of the electron bunch then produces radiation at a higher harmonic after e… more
Date: July 16, 2004
Creator: Penn, G.; Reinsch, M.; Wurtele, J.; Corlett, J. N.; Fawley, W. M.; Zholents, A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Optimization Studies of the FERMI at ELETTRA FEL Design

Description: The FERMI at ELETTRA project at Sincotrone Trieste involves two FEL's, each based upon the principle of seeded harmonic generation and using the existing ELETTRA injection linac at 1.2 GeV beam energy. Scheduled to be completed in 2008, FEL-1 will operate in 40-100 nm wavelength range and will involve one stage of harmonic up-conversion. The second undulator line, FEL-2, will begin operation two years later in the 10-40 nm wavelength range and use two harmonic stages operating as a cascade. The… more
Date: August 25, 2005
Creator: De Ninno, Giovanni; Fawley, William M.; Penn, Gregory E. & Graves,William
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The Induction of Chaos in Electronic Circuits Final Report-October 1, 2001

Description: This project, now known by the name ''Chaos in Electronic Circuits,'' was originally tasked as a two-year project to examine various ''fault'' or ''non-normal'' operational states of common electronic circuits with some focus on determining the feasibility of exploiting these states. Efforts over the two-year duration of this project have been dominated by the study of the chaotic behavior of electronic circuits. These efforts have included setting up laboratory space and hardware for conductin… more
Date: April 1, 2003
Creator: R.M.Wheat, Jr.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Spontaneous and amplified radiation at the initial stage of a SASE FEL.

Description: At the initial stage of a self-amplified spontaneous emission (SASE) free-electron laser (FEL), spontaneous undulator radiation in certain experimental configurations can dominate the amplified signal over an extended undulator distance. In this paper they study both the spontaneous and the amplified radiation in the framework of the paraxial wave equation and determine the transition from the dominance of spontaneous emission to exponential amplification. They compare theoretical expectations … more
Date: November 1, 2002
Creator: Huang, Z. & Kim, K. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Optimization of the LCLS X-Ray FEL Output Performance in the Presence of Strong Undulator Wakefields

Description: The Linac Coherent Light Source (LCLS) Free-Electron Laser will operate in the wavelength range of 1.5 to 15 Angstroms. Energy loss due to wakefields within the long undulator can degrade the FEL process by detuning the resonant FEL frequency. The wakefields arise from the vacuum chamber wall resistivity, its surface roughness, and abrupt changes in its aperture. For LCLS parameters, the resistive component is the most critical and depends upon the chamber material (e.g. Cu) and its radius. To … more
Date: March 17, 2006
Creator: Reiche, S.; Bane, K. L. F.; Emma, P.; Huang, Z.; Nuhn, H. D.; Stupakov, G. V. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

LCLS X-Ray FEL Output Performance in the Presence of Highly Time-Dependent Undulator Wakefields

Description: Energy loss due to wakefields within a long undulator, if not compensated by an appropriate tapering of the magnetic field strength, can degrade the FEL process by detuning the resonant FEL frequency. The wakefields arise from the vacuum chamber wall resistivity, its surface roughness, and abrupt changes in its aperture. For LCLS parameters, the resistive-wall component is the most critical and depends upon the chamber material (e.g., Cu) and its radius. Of recent interest[1] is the so-called '… more
Date: September 30, 2005
Creator: Fawley, W. M.; Bane, K. L. F.; Emma, P.; Huang, Z.; Nuhn, H. D.; Stupakov, G. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Start-Up of FEL Oscillator from Shot Noise

Description: In free-electron laser (FEL) oscillators, as inself-amplified spontaneous emission (SASE) FELs, the buildup of cavitypower starts from shot noise resulting from the discreteness ofelectronic charge. It is important to do the start-up analysis for thebuild-up of cavity power in order to fix the macropulse width from theelectron accelerator such that the system reaches saturation. In thispaper, we use the time-dependent simulation code GINGER [1]toperformthis analysis. We present results of this … more
Date: January 25, 2007
Creator: Kumar, V.; Krishnagopal, S. & Fawley, W. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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