In support of the development of a multiple stage pulse modulator at the Los Alamos National Laboratory, we have developed a first generation, multiple output timing and trigger generator. Exploiting Commercial Off The Shelf (COTS) Micro Controller Units (MCU's), the timing and trigger generator provides 32 independent outputs with a timing resolution of about 500 ns.

A 1/10(th) scaled prototype pulse modulator for an Inertial Electrostatic Confinement (IEC) neutron source has been designed and tested at Los Alamos National Laboratory (LANL). The scaled prototype modulator is based on a solid-state Marx architecture and has an output voltage of 13 kV and an output current of 10 A. The modulator has a variable pulse width between 50 pis and 1 ms with < 5% droop at all pulse widths. The modulator operates with a duty factor up to 5% and has a maximum pulse repetition frequency of 1 kHz.The use of a solid-state Marx modulator in this application has several potential benefits. These benefits include variable pulse width and amplitude, inherent switch overcurrent and transient overvoltage protection, and increased efficiency over DC supplies used in this application. Several new features were incorporated into this design including inductorless charging, fully snubberless operation, and stage fusing.The scaled prototype modulator has been tested using a 1 k Omega resistive load, Test results are given. Short (50 mu s) and long (1 ms) pulses are demonstrated as well as high duty factor operation (1 kHz rep rate at a 50 mu s pulse width for a 5% duty factor). Pulse agility of the modulator is demonstrated through turning the individual Marx stages on and off in sequence producing ramp, pyramid, and reverse pyramid waveforms.

Currently ongoing at Los Alamos National Laboratory is a program to develop high-power, planar 100-300 GHz traveling-wave tubes (TWTs). The promise of planar TWT technology is: 1) the radio-frequency (RF) structures lend themselves well to established micro-fabrication techniques: and 2) by spreading the electron beam in one dimension, we effectively eliminate the beam self force and can transport a high net beam current, resulting in very high-power devices. An enabling technology for this effort is a sheet electron beam source

Currently ongoing at Los Alamos National Laboratory is a program to develop high-power, planar 100 300 GHz traveling-wave tubes. A necessary part of this effort is a sheet electron beam source. Previously, we have described a novel asymmetric solenoid lens concept for transforming the circular beam from a high-perveance electron gun to a planar configuration. The lens is a standard electromagnetic solenoid with elliptical, instead of circular, pole apertures. The elliptical pole openings result in asymmetric focusing, which in turn forms an elliptical sheet beam suitable for our planar structures. Here we report the first experimental demonstration of this lens.

An IGBT modulator has been developed to drive a 120 kV, 23 A Pierce electron gun. The modulator is capable of producing pulses up to 10 mus in width at repetition rates up to 10 Hz with no active reset. The pulse rise time on the electron gun will be approximately 2 mus and the remaining 8 mus of flattop is tuned to have a ripple of less than 1 percent rms. The modulator technology was developed from a previous 50 kV prototype. The modulator consists of six boards, each with one EUPEC IGBT that drives a single common step-up transformer wound on METGLAS 2605 SC cores. The six transformer cores share a common bifilar output secondary winding. The modulator uses a fiber optic trigger system and has a high voltage cable output with an epoxy receptacle on the oil end and a ceramic receptacle on the vacuum end. The 120 kV electron gun was manufactured by MDS Co. and will be used to generate sheet electron beams from the standard pencil beam produced by the Pierce electron gun

Simulations have indicated that emerging electron sheet-beam technology can drive simple rippled and stepped waveguide traveling-wave tubes with extremely high gain. There are many design possibilities that need to be evaluated. The interaction can be made with the n=-1 (backward wave), n=0 (fundamental forward wave), or n=+1 (first space harmonic forward wave) interactions. In this paper, we discuss some of the fundamental design issues.

We have designed and are testing a large orbit gyroklystron amplifier for 1.3 GHz operation in 65 ns pulses. The ultimate power output goal is 500 MW with a gain in excess of 20 dB. This initial investigation is intended to lay the groundwork for operation at 11.4 GHz for particle accelerator applications, and also at frequencies of up to 35 GHz for other uses. Computational design has been performed with the resonant cavity code MAFIA and the particle in cell codes MERLIN and ISIS. Electron beam optics through a magnetic cusp was also studied with ISIS and MERLIN, and verified experimentally, to develop a suitable electron beam trajectory from the diode into the resonator region. Performance tests of a single stage device have been performed. An unsaturated gain of 43 dB has been observed using 4 kW of input drive, yielding an amplified output of 100 MW. >

A new method of RF communications with inherent security has been demonstrated at Los Alamos using chaos masking. In the past several years many papers have described this secure chaos concept theoretically but LANL has the first operating prototype communications system. This chaos communications method is similar to spread spectrum techniques. The chaos masking of a transmitted signal is created by operating a non-linear amplifier (TWT) in saturation with controlled feedback. The system receiver uses an identical TWT that de-codes the chaos masking similar to the correlation methods of a spread spectrum receiver

Thermally-induced Doppler broadening of neutron absorption resonances can be used as a unique signature of the temperature of individual isotopes in a mixture. This principle can be exploited for temperature measurements in situations where conventional measurement techniques are not available, such as measurement of temperatures of individual parts of a system in a severe environment, or of components selectively heated by chemical, electromagnetic, or nuclear processes. Interpretation of the broadened absorption data is normally done by comparison to a nuclear physics model of the absorption process. This paper reports a study of the feasibility of interpreting the data with a trained neural network model.