Wide-aperture cathodoluminescent light source based on an open discharge

The feasibility of an effective high-luminance light source based on an open discharge is considered. Experimental data for the light characteristics of different cathodoluminescent screens are presented. Phosphor coatings are excited by an electron beam initiated by a planar cathode-grid injector in an inert gas atmosphere. The feasibility of maintaining an open discharge using continuous or pulsed-periodic excitation of the gas medium in the light emitter is discussed. The use of the specular method to excite the phosphor coating of the screen makes it possible to achieve a higher luminance and a higher luminous efficacy in comparison with these characteristics for cathodophosphors. The design of the cathode-grid unit allows for a large surface area of the electron injector, making it promising for wide-aperture light sources.     

A surface discharge as a source of intense light flashes

Surface sparks on TiO₂ ceramic in Ar and Xe have been used; the intensity is greater than that of an open discharge by an order of magnitude. Under limiting conditions the discharge radiates as a blackbody at 63 000° K in Ar and at 40 000° K in Xe. Spectra and high-speed photographs of the discharge channel are presented.     

弹载脉冲光源有效光强空间分布测量装置研究

研究了脉冲光源有效光强空间分布的Blondel-Rey法,采用复合梯形数值积分实现了瞬时光强的测量,并对高色温光源测量时的光谱失配校正进行了分析。构建了基于双反射镜同步测量原理的脉冲光源有效光强空间分布测量装置,详细分析了全空间分布式旋转平台、脉冲光强探测系统、光谱失配校正用高分辨率光谱仪等重点组成部件。采用高色温调制光源对测量装置进行了校准。最后,对该装置的测量不确定度进行了分析,其扩展不确定度可以达到3.0%。     

Studies of a light source based on the retardation of supersonic pulse discharge jets

The spectral distribution of the radiated energy of an imploded plasma formed through the collision of a super-sonic plasma jet of a pulse discharge against a stationary obstacle was studied. Its brightness temperature and absorption were measured. It is shown that the plasma can served as a source of a continuous spectrum with an energy distribution similar to that of an absolute blackbody. The brightness temperature of the source was variable over a broad range by appropriate adjustment of the discharge conditions.The authors are very grateful to M. A. El'yashevich for his interest in the present study and for his valuable comments on the results.     

Comparison of discharge lamp and laser pumped cesium magnetometers

We have performed a comparison of laser (LsOPM) and lamp (LpOPM) pumped cesium vapor magnetometers. Although the LsOPM operated 50% above its shot-noise limit we found an intrinsic sensitivity of 15 fT/√Hz and 25 fT/√Hz for the LsOPM and the LpOPM, respectively. Two modes of operation, viz. the phase-stabilized and the self-oscillating modes, were investigated and found to yield a similar performance. We have compared the performance of the LsOPM and the LpOPM directly by simultaneous measurements of field fluctuations of a 2-μT magnetic field inside a multilayer magnetic shield and have used one of the magnetometers for an active field stabilization. In the stabilized mode we found a gradient instability of 25 fT within an integration time of 100 s, which represents an upper limit of the long-term stability of the magnetometers. Our research is motivated by the need for an improved control of magnetic fields and gradients in a planned neutron electric dipole experiment.This revised version was published online in August 2005 with a corrected cover date.     

High-voltage pulsed discharge in an electron source with a plasma cathode

The nature of and mechanism for producing a high-voltage discharge in an electron source with a plasma cathode are investigated. The possibility of generating pulsed electron currents with an amplitude of 10³–10⁴ A and a length of 10^–6 sec is considered.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 117–121, October, 1973.The authors thank B. M. Koval'chuk for help in developing the experimental arrangement and G. A. Mesyates for constant attention to the work and discussion of the results.     

Three-coupled-quantum-well nanostructures as a source of far-infrared entangled light

A scheme is proposed to achieve the two-mode entanglement in an asymmetric semiconductor three-coupled-quantum-well (TCQW) system based on the intersubband transitions (ISBTs). In the present scheme, the TCQW structure is trapped into a doubly resonant cavity, and the required quantum coherence effects is induced by the corresponding ISBTs, which is the key of realising entanglement. By numerically simulating the dynamics of the system, we show that the entangled cavity modes with the far-infrared wavelengh can be realised in this TCQW system. The present research provides an efficient approach to achieve far-infrared entangled light in the semiconductor nanostructures, which may have significant impact on the progress of solid-state quantum information theory.     

The delay of arc starvation saturation in an intense ion source discharge

Wall neutralization of effusing energetic plasma ions results in a substantial population of very energetic neutrals which are able to readily penetrate into the intense discharge core. These fast neutrals delay arc starvation and, when reionized, accompany an increase in ion plasma temperature.     

Vacuum anodic discharge as source of ionized fluxes of coating material

Cathodic and anodic discharges are effective sources of coating material ionized fluxes. Of special interest is the use of anodic discharges, particularly discharges with a thermoelectronic cathode. The discharge forms fluxes in high vacuum with regulated ionization and the absence of micro liquid droplets. The initiation conditions and characteristics of the discharge in the voltage range from 50 to 500 V with currents up to 5 A were investigated. The dependence of vacuum, interelectrode distance, and cathode heating temperature were considered. Conditions for the production of coating material fluxes with maximum ionization were established.