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in subjects: "Amplification"

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Recent US target-physics-related research in heavy-ion inertial fusion: simulations for tamped targets and for disk experiments in accelerator test facilities

Within the last few years, there have also appeared in the Heavy-Ion Fusion literature several studies of targets which have outer tampers. One-dimensional simulations indicate higher target gains with a judicious amount of tamping. But for these targets, a full investigation has not been carried through in regards to conservative criteria for fluid instabilities as well as reasonable imperfections in target fabrication and illumination symmetry which all affect target ignition and burn. Compar… more

Date: June 24, 1982

Creator: Mark, J.W.K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Optimization of microchannel plate multipliers for tracking minimum-ionizing particles

The progress in development of special Microchannel Plates for particle tracking is reported. The requirements of (1) high spatial resolution; (2) high density of information; and (3) rate capability were found to be satisfied in a thick Microchannel Plate with a CsI coating operating in a focusing magnetic field. The measurements of the Microchannel Plate detection efficiency, gain and noise are presented for several detectors. The pictures of the passage and interaction of the high energy cha… more

Date: January 1, 1981

Creator: Oba, K.; Rehak, P. & Potter, D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Efficient forward conversion in a Raman generator

Stimulated Raman scattering of an XeCl laser at 308 nm in a high pressure H/sub 2/ cell shows anomalously high conversion into first Stokes (S1) when a pumping geometry with a Fresnel number near unity is used. Specifically a quantum efficiency of 88% is obtained into S1. Comparison with a plane-wave model indicates that a theory including diffraction and 4-wave mixing may be necessary to understand the anomalous holdoff of the second Stokes component. 10 references.

Date: January 1, 1984

Creator: Carlsten, J.L.; Telle, J.M. & Wenzel, R.G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Configuring the SLC linac for injection into PEP

From time to time the normal SLC physics program is to be interrupted so that beam can be delivered to PEP. In order that the switch to PEP injection (and the switch back again) can be accomplished quickly and easily, the gun, the damping rings, the linac phase ramp, the energy profile of the linac klystrons for the scavenger bunch, and the entire positron production system are to be kept the same as in the SLC configuration. What mainly remains to be changed is the linac klystron profile for t… more

Date: December 15, 1989

Creator: Bane, K.L.F.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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The Fresh-Bunch' technique in FELs

The 'Fresh Bunch' technique is being proposed as a method of increasing the gain and power of FEL amplifiers in which the length of the optical radiation pulse is shorter than the length of the electron bunch. In multi-stage FEL, electron beam energy spread is increased by the FEL interaction in the early stages. In the 'Fresh Bunch' technique, the low energy spread of the electron beam is recovered by shifting the radiation pulse to an undisturbed part of the electron bunch, thus improving the… more

Date: January 1, 1991

Creator: Ben-Zvi, Ilan; Yang, K. M. & Yu, L. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Lasers for open structures

Laser-driven accelerator schemes place unique demands on the specifications of the invoked laser systems. We review the laser requirements for driving open microstructures. The specific advantages and disadvantages that lasers bring to this scheme are listed, and the appropriateness and scalabitity of existing technology is discussed. Finally we review the plans and status for the laser activities of the Brookhaven/Los Alamos collaboration on a proof-of-principle experiment.

Date: January 1, 1986

Creator: Bigio, I.J.; Kurnit, N.A.; Harrison, R.F. & Shimada, T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The Effect of Wiggler Errors on FEL Gain

For an FEL operating in the exponential regime before saturation, we present an analytic description of the effect on the gain of longitudinal velocity variations arising from wiggler field errors. The average gain reduction and the width of the output power distribution are expressed in terms of the mean square average of the ponderomotive phase shift per gain length. A scheme for correcting the electron trajectory using position monitors and dipole correctors is analyzed. Our work is directly… more

Date: January 1, 1991

Creator: Yu, L. H.; Krinsky, S. (Brookhaven National Lab., Upton, NY (United States)); Gluckstern, R. L. & van Zeijts, J. B. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Inertial fusion research at Lawrence Livermore National Laboratory: program status and future applications

The objectives of the Lawrence Livermore National Laboratory (LLNL) Laser Fusion Program are to understand and develop the science and technology required to utilize inertial confinement fusion (ICF) for both military and commercial applications. The results of recent experiments are described. We point out the progress in our laser studies, where we continue to develop and test the concepts, components, and materials for present and future laser systems. While there are many potential commerci… more

Date: June 5, 1986

Creator: Meier, W. R. & Hogan, W. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A comparison of three self-tuning control algorithms developed for the Bristol-Babcock controller

A brief overview of adaptive control methods relating to the design of self-tuning proportional-integral-derivative (PID) controllers is given. The methods discussed include gain scheduling, self-tuning, auto-tuning, and model-reference adaptive control systems. Several process identification and parameter adjustment methods are discussed. Characteristics of the two most common types of self-tuning controllers implemented by industry (i.e., pattern recognition and process identification) are su… more

Date: April 1, 1992

Creator: Tapp, P.A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Specific heat loading in Nd:glass lasers

The specific thermal load parameter, chi, for xenon flashlamp-pumped Nd:glass gain media is written as a function of neodymium concentration, pump pulse duration, and energy extraction efficiency. The currently available data on radiative and nonradiative decay probabilities of several commercial Nd:glasses are used to calculate and graph specific thermal load parameter values. By factoring these results into performance scaling relationships for zig-zag and disk lasers, specific Nd:glasses can… more

Date: August 7, 1985

Creator: Krupke, W. F.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Design study of a 7 kW, visible wavelength FEL

The MIT Lincoln Laboratory is investigating the possibility of building a free electron laser (FEL) operating at an average power of about 7 kW at wavelengths of 500--600 nm. Additional specifications for the FEL include a bandwidth of less than 0.1 cm{sup {minus}1} and a micropulse separation of less than 10 ns. The design study has investigated the basic design parameters of the FEL including an analysis of the electron accelerator, beam line, wiggler and optical cavity. A nonlinear model of … more

Date: January 1, 1990

Creator: Chen, S.C.; Danly, B.G.; Temkin, R.J.; Wurtele, J. & Yang, B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Gated SIT vidicon streak tube

A recently developed prototype streak tube designed to produce high gain and resolution by incorporating the streak and readout functions in one envelope thereby minimizing photon-to-change transformations and eliminating external coupling losses is presented. The tube is based upon a grid-gated Silicon-Intensified-Target Vidicon (SITV) with integral Focus Projection Scan (FPS) TV readout. Demagnifying electron optics (m=0.63) in the image section map the 40-mm-diameter photocathode image unto … more

Date: January 1, 1985

Creator: Dunbar, D. L.; Yates, G. J. & Black, J. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Generation of coherent soft x-rays using a single-pass free-electron laser amplifier

We consider a single-pass free-electron laser (FEL) amplifier, driven by an rf-linac followed by a damping ring for reduced emittance, for use in generating coherent light in the soft x-ray region. The dependence of the optical gain on electron-beam quality, studied with the three-dimensional FEL simulation code FELEX, is given and related to the expected power of self-amplified spontaneous emission. We discuss issues for the damping ring designed to achieve the required electron beam quality. … more

Date: January 1, 1988

Creator: Wang, T. F.; Goldstein, J. C.; Newnam, B. E. & McVey, B. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Recent US target-physics-related research in heavy-ion inertial fusion: simulations for tamped targets and for disk experiments in accelerator test facilities

Calculations suggest that experiments relating to disk heating, as well as beam deposition, focusing and transport can be performed within the context of current design proposals for accelerator test-facilities. Since the test-facilities have lower ion kinetic energy and beam pulse power as compared to reactor drivers, we achieve high-beam intensities at the focal spot by using short focal distance and properly designed beam optics. In this regard, the low beam emittance of suggested multi-beam… more

Date: March 22, 1982

Creator: Mark, J.W.K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Theoretical study of a high-extraction efficiency undulator for a free-electron laser oscillator

Theoretical issues in designing a high-extraction efficiency undulator for a free-electron laser oscillator are discussed. Assuming that an undulator system consists of a prebuncher undulator and a main undulator separated by a drift, design criteria of the untapered prebuncher are studied. The main undulator is designed parabolically tapered in wave number from no taper to a 30% taper. A small signal gain is enhanced at the low taper section, and the large signal gain is enhanced at the high t… more

Date: September 1, 1986

Creator: Takeda, H.; McVey, B.D. & Goldstein, J.C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fifty megawatt klystron for the Stanford Linear Collider

The proposed Stanford Linear Collider (SLC) has been designed to provide 50 on 50 GeV electron-positron collisions. The performance of the 240 klystrons driving the two-mile long linac must be upgraded to achieve at least 50 Megawatts of peak power output at a pulse of 5 ..mu..sec and a pulse repetition frequency of 180 pulses per second. The operating frequency of the upgraded linac will continue to be 2856 MHz. A klystron amplifier meeting these new requirements has been designed to operate a… more

Date: September 1, 1983

Creator: Lee, T. G.; Lebacqz, J. V. & Konrad, G. T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

ICF drivers: a comparison of some new entries and old standbys. Revision 1

There has been a great deal of progress in recent years on the development of solid state and KrF lasers, light ion diodes, and heavy ion accelerators for use as drivers in inertial confinement fusion (ICF) facilities. Two relatively new entries in the ICF driver derby are the free electron laser (FEL) and the compact torus (CT). The status and remaining technological challenges of each potential driver are described. The author discusses driver performance criteria for various reactor applicat… more

Date: July 31, 1986

Creator: Hogan, W.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Extension of free-electron lasers into the extreme ultraviolet

Encouraged by experimental operation of free-electron lasers in the visible to far-infrared, several research centers are now designing and/or building devices to extend into the vacuum-ultraviolet and soft x-ray regions below 100 nm, collectively referred to as the extreme ultraviolet. Here the peak- and average-power output of FEL oscillators and amplifiers should surpass the capabilities of any existing, continuously tunable photon sources by many orders of magnitude. These devices are certa… more

Date: January 1, 1988

Creator: Newman, B.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Count rate performance of a microchannel plate photomultiplier

The count rate dependent gain change of a microchannel plate photomultiplier has been measured. Gain changes of 60% have been observed for count rates in excess of 2 x 10/sup 5/ s/sup -1/. The microchannel plate photomultiplier was used as a multiplying element of a scintillation detector system using NaI(Tl) as the scintillator. Data are compared to a simplified model of this form of photomultiplier.

Date: January 1, 1981

Creator: Nieschmidt, E.B.; Lawrence, R.S.; Gentillon, C.D. & Vegors, S.H. Jr.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Uniform laser ablative acceleration of targets at 10/sup 14/ W/cm/sup 2/

We present the first detailed investigations of the ablative acceleration of planar targets while simultaneously using high irradiance (10/sup 14/ W/cm/sup 2/), large focal diameters (1 mm) and long laser pulse duration (3 nsec). Included are measurements of target preheat, ablation pressures and uniformity achieved under these conditions. Targets were accelerated to high velocities with velocity profile uniformity approaching that required for high gain pellet implosions.

Date: August 10, 1982

Creator: Obenschain, S. P.; Whitlock, R. R.; McLean, E. A.; Ripin, B. H.; Price, R. H.; Phillion, D. W. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

First operation of the Los Alamos free-electron laser oscillator

An FEL oscillator has been operated at wavelengths between 9 and 11 ..mu..m with a peak intracavity power of about 20 MW and an average output power of 1 kW in 70- ..mu..s pulses. We present the design parameters and operating characteristics. We report measurements of spontaneous emission, start-up of oscillations, and signal growth through approx. 9 orders of magnitude to saturation. The dependence of gain and saturation on cavity length, alignment, beam parameters, and other critical variabl… more

Date: January 1, 1983

Creator: Warren, R. W.; Newnam, B. E.; Stein, W. E.; Winston, J. G.; Sheffield, R. L.; Lynch, M. T. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Kinetic modelling of krypton fluoride laser systems

A kinetic model has been developed for the KrF* rare gas halide laser system, specifically for electron-beam pumped mixtures of krypton, fluorine, and either helium or argon. The excitation produced in the laser gas by the e-beam was calculated numerically using an algorithm checked by comparing the predicted ionization yields in the pure rare gases with their experimental values. The excitation of the laser media by multi-kilovolt x-rays was also modeled and shown to be similar to that produce… more

Date: November 1, 1983

Creator: Jancaitis, K.S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

FEL gain taking into account diffraction and electron beam emittance; generalized Madey's theorem

We derive a formula for the free electron laser gain in the small-signal, low-grain regime which resembles closely the 1-D formula but taking into account the effect of wave diffraction and electron beam divergence and betatron motion. The formula is cast in a form which exhibits clearly the role of the transverse phase space distribution of photons and electrons. 8 refs.

Date: August 1, 1991

Creator: Kim, Kwang-Je.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Free electron lasers for the production of infrared and millimeter waves

A review is presented of free electron laser (FEL) generation of electromagnetic radiation in the range from 0.5 ..mu..m to 10 mm, citing several experiments and theoretical efforts.

Date: July 1, 1986

Creator: Sessler, Andrew M.

Item Type: Article

Partner: UNT Libraries Government Documents Department