摘要:

The 3‐MeV protons created byd(d, p)tfusion reactions in a moderately sized tokamak leave the plasma on trajectories determined by the position of their birth and by the poloidal magnetic field. Pitch‐angle resolution of the escaping 3‐MeV protons can separately resolve the spatial distribution of thed(d, p)tfusion reactions and the poloidal field distribution inside the tokamak. These diagnostic techniques have been demonstrated on PLT with an array of collimated surface barrier detectors.

ISSN:0034-6748    

DOI:10.1063/1.1138277

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

We present a new method of plasma potential measurement with a differential emissive probe. The dc heated probes are combined with a feedback loop control circuit to measure plasma potential automatically. In addition, it is shown that connecting to the central point of the filaments reduces the effect on the emissive currents of voltage drops across the filaments. The decay time constant of half‐cycle heated emissive probe current during the off heating cycle is shown to depend on the initial emission current and on the bias voltage.

ISSN:0034-6748    

DOI:10.1063/1.1138278

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Energy spectra of neutral hydrogen beams produced at the prototype JT‐60 neutral beam injector unit were measured by the solid‐state detector which was developed for a neutral particle analyzer for fusion devices. The ion beam species ratio estimated from the energy spectra agreed well with that measured by the Doppler‐shift spectrometer.

ISSN:0034-6748    

DOI:10.1063/1.1138279

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Tunable laser spectroscopy has recently been used in diagnosing the chemistry and physics of plasma, combustion, and chemical vapor deposition reactors. However, the impact of these spectroscopic techniques on real‐time process monitoring has been limited to date. One of the reasons for this is the difficulty in tuning the laser frequency to a specific transition and having it remain there for more than a few minutes. I describe a simple method by which these difficulties can be circumvented and frequency tuning can be controlled remotely. A microprocessor is used to regulate the gas flow of a pressure tuned oscillator so that constant pressure (and, indirectly, freqency) is maintained (for excitation of a particular transition) or swept (to record an excitation or absorption spectrum). As a natural extension the pressure can be slaved to a wavemeter so that direct frequency control can be achieved.

ISSN:0034-6748    

DOI:10.1063/1.1138280

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

High‐performance electrodes for gas discharge devices such as lasers often require surfaces of compound curvature which are both difficult to describe and difficult to manufacture. This paper describes a simple microcomputer method for generating sophisticated electrode shapes on a numerically controlled milling machine. As an example, a Rogowski cross‐section electrode with end profiling was fabricated using an Apple IIe computer with an RS‐232 serial interface to the milling machine.

ISSN:0034-6748    

DOI:10.1063/1.1138281

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A commercial vidicon detector, designed for scientific purposes with user‐controlled target scanning, was modified to produce a computer‐controlled optional composite video signal permitting rapid acquisition of two‐dimensional data. A video preamplifier and a processing amplifier were incorporated in the camera head, and a special function card, providing the composite video signals, was inserted into a spare slot of the control unit; minor wiring changes were required to accommodate these modifications. A resolution in excess of 400 lines is obtained in the horizontal direction, and a 10‐&mgr; reticle is clearly resolved through a microscope.

ISSN:0034-6748    

DOI:10.1063/1.1138282

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A method of internal calibration is developed that allows one to ascertain the monexponentiality of a reference compound fluorescence decay and to determine its lifetime with high accuracy. It is shown that when the fluorescence decays of several samples are analyzed as a function of the reference lifetime, which is used to calculate the ‘‘lamp profile,’’ all the data are consistent with each other only if the fluorescence of all the used compounds decays monoexponentially and the correct lifetime forp‐terphenyl, which is used as reference compound, is between 1.02 and 1.03 ns.

ISSN:0034-6748    

DOI:10.1063/1.1138283

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A heterodyne Michelson interferometer‐type laser probe has been designed and constructed. The probe is used to measure subangstrom continuous ultrasonic displacements from rough surfaces. The probe optical and electronic design ensure optimal use of the available laser intensity, immunity from ambient vibrations, and ease of calibration.

ISSN:0034-6748    

DOI:10.1063/1.1138284

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

An optical tracking system comprising a visible HeNe laser, an imaging detector, and a microprocessor‐controlled mirror, has been designed to track a moving retroreflector located up to 500 m away from an atmospheric instrument and simultaneously direct spectrally tunable infrared laser radiation to the retroreflector for double‐ended, long‐path absorption measurements of atmospheric species. The tracker has been tested during the recent flight of a balloon‐borne tunable diode laser absorption spectrometer which monitors the concentrations of stratospheric species within a volume defined by a 0.14‐m‐diameter retroreflector lowered 500 m below the instrument gondola.

ISSN:0034-6748    

DOI:10.1063/1.1138285

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Aerosol seeding of gas flows by laser‐induced particle formation is demonstrated. A pulsed Nd:YAG laser (1.06 &mgr;) is used to optically break down a mixture of SF6and H2in an inert carrier gas. Small sulfur particles form quickly and can be used to visualize gas flows by Mie scattering.

ISSN:0034-6748    

DOI:10.1063/1.1138286

出版商:AIP    

年代:1985

数据来源: AIP