摘要:

Experimental data for five fusion reactions of D, T, and3He below 1 MeV are reviewed. Analytical formulas are given for the reaction rates as functions of the temperature, up tokT=100 keV. These formulas depart appreciably from some currently used whenkT<3 keV.

ISSN:0021-8979    

DOI:10.1063/1.326748

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

In the presence of an ambient medium and an external magnetic field, ultrarelativistic charged particles emit synchrotron‐?erenkov radiation. For cases in which the classical synchroton frequency greatly exceeds any characteristic absorption frequency of the medium, i.e., when the medium can effectively be treated as a free‐electron gas, the photon production rates depend sensitively on the ratio of the synchroton frequency to the relativistically boosted electron plasma frequency. In principle this connection can be exploited for the construction of high‐energy electron detectors (E≳2 GeV). These counters allow for the simultaneous determination of the electron energy, and a mass discrimination between electrons and higher‐mass singly charged particles. The relative merits of synchrotron‐?erenkov detectors and some standard counters are briefly discussed.

ISSN:0021-8979    

DOI:10.1063/1.326749

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Stopping powers derivable from Lindhard’s dielectric theory of stopping for a charged particle in a uniform electron gas are calculated as a continuous function of electron density for a wide variety of projectile energies ranging from 102to 104keV/amu. Results are presented for electron densities varying from 1022to 1032electrons/cm3, a range which includes electron densities generally found for the energy bands of solids and for the atomic levels of atoms.

ISSN:0021-8979    

DOI:10.1063/1.326750

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The role of bromine‐reactive common metallic impurities on the life and output of a quartz bromine lamp has been examined. A series of tests with one lamp type showed that impurities such as Fe, Ni, Cr, and Cu reacted with bromine and formed stable bromides that deposited at the cooler end sections of the quartz bulb. If the minimum temperature of this deposit zone was increased from ∼300 to ≳ 500 °C during lamp burning, these deposits became volatile and the regenerative cycle became functional for those cases where the metallic‐impurity–to–bromine ratio was high and had previously affected the cycle. The metallic impurities were identified in the deposits; their release was also monitored during lamp burning. A thermochemical interpretation of the results of the tests and analytical findings is presented.

ISSN:0021-8979    

DOI:10.1063/1.326751

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The ratio of emission of the electron‐excitedK&bgr; lines to the sum ofK&agr; andK&bgr; lines was measured for several elements with a lithium‐drifted silicon detector. The measured intensities were corrected for background, line overlap, and absorption within the target and within the detector. The results are compared with those obtained by other investigators.

ISSN:0021-8979    

DOI:10.1063/1.326752

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The principal processes controlling the emission of charged and neutral particles and complexes from positive liquid‐gallium points for voltages at or above ∼5 kV are briefly summarized. The components of the extractor and collector current and the fluctuations of the latter are investigated as well as the dependence of the currents on retarding and accelerating potentials that are applied to the collector. The effect of secondary electrons released from the collector by the impact of fast positive ions is examined as well as the suppression of these electrons by means of reversing or deflecting electric or magnetic fields of moderate magnitude. Feeble emission of visible light is observed at the collector surface when condensed gallium evaporates under bombardment of fast particles. The formation and life of protrusions and of the flow of neutral atoms and droplets are discussed.

ISSN:0021-8979    

DOI:10.1063/1.326753

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The Boersch effect is calculated for two electron‐beam configurations: an ideal lens leading to a single crossover and an electron gun which has no crossover. The results agree with previous work both as to the spatial spreading caused by space charge and the energy broadening due to electron‐electron interactions. The energy spread produced in a gun with no crossover is clearly demonstrated and shown as a function of emitting area and beam current.

ISSN:0021-8979    

DOI:10.1063/1.326754

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A description is presented of an experimental study of the growth and propagation of a large‐amplitude slow space‐charge wave on a weakly relativistic electron beam. The wave is grown as a result of an unstable interaction between a slow space‐charge wave on the electron beam, and the TM modes of a periodic waveguide. Following wave growth the modulated beam is propagated through a cylindrical waveguide. Experimental results show that we have grown, and can propagate, a coherent wave, having a peak electric field of 60 kV/cm, with a phase velocity of 0.29c. The results presented have application to the collective acceleration of ions in intense relativistic electron beams.

ISSN:0021-8979    

DOI:10.1063/1.326755

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The rotationally symmetric solution &fgr; (r,z) satisfying ∇2&fgr;=0 in the region exterior to a cylinder of radiusAon which the boundary values are given by &fgr; (A,z<0) =&fgr; (A,z≳L) =0 and &fgr; (A,z) =F(z) for 0<z<Lis represented by a Fourier‐Bessel integral, which can be approximated by a Fourier‐Bessel series. It is shown how the quality of the approximation can be improved by ensuring that the period of the series is sufficiently large. For a finite period the error of the approximation can be understood either in terms of induced charge distributions on two parallel planes, or by considering an infinity of image charge distributions atr=A. The error can be reduced by eliminating the images of potential distributions, which is done numerically through the addition of a suitably chosen auxiliary Fourier‐Bessel series.

ISSN:0021-8979    

DOI:10.1063/1.326756

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The results are reported of a theoretical study on the pulsed HBr chemical laser using a mixture of H2and Br2, utilizing numerical analysis by pulsed chemical‐laser code. The HBr laser output performance as characterized by laser energy, power, pulse width, and vibrational population distribution was examined as a function of the initial dissociation rate and the H2/Br2mixture ratio for a mixture at 100 Torr. The effect of HBr(0) in an HBr chemical laser must be taken into account, especially in applying HBr chemical lasers to the optical pumping of CO2and HBr gases, since the 4.2‐&mgr;m laser emission useful for such pumping comes from theP1−0(J) andP2−1(J) lines. In this paper, the effect of added HBr(0) on output performance was also studied.

ISSN:0021-8979    

DOI:10.1063/1.326757

出版商:AIP    

年代:1979

数据来源: AIP