Showing papers on "Full width at half maximum published in 1976"

Very high radiance edge-emitting LED

Abstract: In this paper we describe a new light-emitting diode (LED) whose radiance is 1000 W/cm2sr, an order of magnitude higher than any previous LED The LED is an (AlGa)As double-heterojunction edge-emitting structure This structure acts as a waveguide for the internally generated light, and with appropriate Al concentration difference at the heterojunctions ( \Deltax \approx 03 ) and active region width (∼500A), the radiation pattern perpendicular to the junction can be less than 30° (FWHM) For fiber-optic communications this LED is capable of coupling 850 μw, at a coupling loss of only -10 dB into a 014-numerical-aperture (NA), 90-μm-diam low-loss fiber The LED is capable of being directly modulated at 250 MHz and has a spectral width of less than 300 A

Pseudopotential theory of the width of the long wavelength plasmon in simple metals

Abstract: The full width at half maximum (FWHM) of long wave-length plasmons in simple metals is derived in a form convenient for application. The line width is a measure of the strength of the pseudopotential, and very good agreement with recent experimental measurements is found for a representative set of nearly-free-electron (NFE) metals. The dispersion of the FWHM is also discussed.

Optimization of isolated electron pulses in the picosecond range from a linear accelerator using a streak camera–TV diagnostic system

Abstract: We describe the technique and the results of a measurement of the width of a fine structure pulse from our L‐band electron linear accelerator. The pulse width was measured by measuring the width of the Cerenkov light pulse generated by the electron beam using a streak camera–TV camera–computer system. With very low beam currents, a pulse width of 20 psec (FWHM) was measured, while at higher beam currents a pulse width of 27 psec was measured showing a space‐charge effect. In addition, a broad energy spectrum for the electrons or improper focusing into a 270° bending magnet was also shown to increase the pulse width of the beam after it had traversed the magnet.

Impulse and Frequency Response of Channel Electron Multipliers

Abstract: Publisher Summary This chapter analyzes the secondary electron multiplication within the channel electron multipliers (CEM) by computer simulation to obtain the impulse response characteristics of a CEM, which is excited by a single electron Transit time, rise time, and full width at half maximum of the output pulse are obtained from the computer simulation The Fourier transform of the output pulse gives the frequency response of the CEM The analysis shows that thinner channel plates with finer capillaries have faster responses Calculations for a channel 40 μm in diameter and 2 mm long operated at 3 kV show it to have a flat response up to 53 GHz and to have an output pulse width of 61 ps The results show that a CEM plate of fine microchannels is superior for high speed operation to the crossed field electron multiplier designed for high speed photon detection The phase shift that has a linear relation to frequency is described It is found that only signal delay is important in describing the transmission of the wave

Neutron spectrum at 0° from 83.7 MeV deuterons on beryllium

Abstract: The neutron spectrum measured at 0\ifmmode^\circ\else\textdegree\fi{} from 83.7 MeV deuteron bombardment of a thick beryllium target is bell-shaped with a peak at about 34 MeV and a full width at half maximum of about 22 MeV. Measurements down to 4 MeV show no indication of an evaporation peak. While the shape of the spectrum calculated on the basis of the Serber model for deuteron stripping is similar to the observed shape, the width of the calculated spectrum is broader than that observed. The broadening occurs primarily on the low-energy side of the spectrum. The same features are revealed in further calculations of the 0\ifmmode^\circ\else\textdegree\fi{} spectrum from 53.8 MeV deuterons on a thick beryllium target.

A crossed beam apparatus for ion-molecule reactions with negative ions

Abstract: An instrument for the study of charge transfer processes and ion-molecule reactions with negative ions has been constructed. It consists of an electron bombardment source, a primary ion mass analyser, an energy analyser and an accelerating lens followed by the reaction chamber and a secondary mass analyser. Mass analysed primary ion beams of experimentally useful intensities are produced over an energy range (in the laboratory system) from 0.2 eV to 100 eV with an energy spread of about 0.2 eV (full width at half maximum) above 2 eV.

Measurement of Energy Distribution of Low Energy Light Ions through Copper Film and its Statistical Analysis

Abstract: Energy distributions of protons and helium ions passing through copper films of thicknesses from 300 to 800 A have been measured in the energy range 4 to 16 keV, and the variation of the full width at half maximum with film thicknesses and average ion energies has been investigated. It is found that this width increases slightly with increasing film thickness and increases in a parabolic form with increasing average ion energy. Those experimental results are analyzed by the statistical procedure of the multiple inelastic collision in which the unevenness of film thickness is taken into consideration, and further, the inelastic scattering process is discussed.