摘要:

We have developed a photonic high‐speed analog data recording system that, when compared with conventional oscilloscope‐based systems, offers greater economy, higher bandwidth, electrical isolation, and compactness. The basis of this approach is to record analog photonic signals rather than analog electrical signals. A key component is the prototype high‐speed multi‐ channel data recorder. Initial demonstrations of this photonic system in pulsed power experiments have already shown its versatility and usefulness. We describe the system and its integration with newly developed photonic sensors and discuss its overall impact in diagnostic technology.

ISSN:0034-6748    

DOI:10.1063/1.1138530

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A new type of plasma calorimeter has been developed for laser light absorption and measurement of laser irradiated targets. The principle of this detector is the same as a bolometer; plasmas and x rays are absorbed by a thin glass plate which is transparent enough for laser light, and temperature rise of the absorber plate is detected by a faint increase of the resistance of a nickel resistance bulb. The structure and application example are described.

ISSN:0034-6748    

DOI:10.1063/1.1138435

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A multichannel heterodyne radiometer in the frequency range 50–75 GHz which has been used to measure the second‐harmonic cyclotron emission of the Thor Tokomak plasma is described. Real‐time frequency switching, analog output averaging, autocalibration, data‐acquisition, and graphical display are all functions performed under control of an Apple II personal computer. Typical experimental results are presented to illustrate the measuring capabilities of the instrument.

ISSN:0034-6748    

DOI:10.1063/1.1138436

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

An optical diagnostic consisting of a periscope which relays images of the torus interior to an array of cameras is used on the Tokamak Fusion Test Reactor (TFTR) to view plasma discharge phenomena and inspect the vacuum vessel internal structures in both the visible and near‐infrared wavelength regions. Three periscopes view through 20‐cm‐diam fused‐silica windows which are spaced around the torus midplane to provide a viewing coverage of approximately 75% of the vacuum vessel internal surface area. The periscopes have  f/8 optics and motor‐driven controls for focusing, magnification selection (5°, 20°, and 60° field of view), elevation and azimuth setting, mast rotation, filter selection, iris aperture, and viewing port selection. The four viewing ports on each periscope are equipped with multiple imaging devices which include: (1) an inspection eyepiece, (2) standard (RCA TC2900) and fast (RETICON) framing rate television cameras, (3) a PtSi CCD infrared imaging camera, (4) a 35‐mm Nikon F3 still camera, or (5) a 16‐mm Locam II movie camera with variable framing rate up to 500 fps. Operation of the periscope‐camera system is controlled either locally or remotely through a computer‐CAMAC interface. A description of the equipment and examples of its application are presented.

ISSN:0034-6748    

DOI:10.1063/1.1138437

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A liquid‐He/liquid‐N2cryostat system has been developed to freeze D2gas and extrude fibers of solid deuterium into a vacuum chamber. Fibers that are 40 &mgr;m in diameter and 10 cm long have been successfully and routinely produced. The fibers are observed to remain constant in physical dimensions for several minutes. A fiber will be used as the electrical load for a pulsed power machine in a program investigating the properties of dense, ohmically heated plasmas for controlled thermonuclear fusion.

ISSN:0034-6748    

DOI:10.1063/1.1138438

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A large area, indirectly heated cathode capable of continuous, high‐ current electron emission is described. The cathode assembly utilizes an indirectly heated lanthanum molybdenum carbide (LaMo) disk as the thermionic electron emitter. Other cathode shapes are also discussed. The disk cathode emits up to 500 A of electrons at an average of 11 A/cm2in continuous operation in a plasma discharge. LaMo material is machinable and is not fragile even after extended operation. Careful fabrication and conditioning of the LaMo carbide surface is required. The electron emission capability depends strongly on producing the proper fine grain structure of the molybdenum carbide surface layer to allow adequate diffusion of lanthanum to the surface. Failure to produce the correct surface structure results in intermittent electron emission. The electron emission was not affected by exposure to both air and water during operation, but the emission is poisoned by small amounts of tungsten on the surface. After proper preparation, this intermediate temperature electron emitter is very rugged and has a long lifetime.

ISSN:0034-6748    

DOI:10.1063/1.1138439

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

Microwave power resonant to the local electron cyclotron frequency has been coupled into the plasma discharge chamber of a hot‐cathode PIG (Philips or Penning Ionization Gauge) ion source. The extracted ion beam was monitored for changes in characteristics of the beam with and without application of the microwave power. No change was seen in the ion charge state distribution. A small but significant reduction in the beam noise level was seen, and this technique may thus find application in situations where beam quiescence is important.

ISSN:0034-6748    

DOI:10.1063/1.1138440

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

The differential ion flux probe (DIF probe) is a scientific instrument capable of deconvolving a multiplicity of ion streams, differing in flow direction and/or energy, and independently determining the flow direction, current density, temperature, and energy of each stream. The original instrument concept was developed for laboratory investigations in the area of plasma dynamics and was reported [N. H. Stone, Rev. Sci. Instrum.48, 1458 (1977). Since then, the DIF probe has been redesigned and developed into a flight instrument to provide measurements of disturbed plasma flow conditions within the terrestrial ionosphere. It has flown on the STS‐3 Space Shuttle mission, on sounding rockets, and recently on the Spacelab‐2 mission as part of the plasma diagnostics package (PDP) experiment. Herein, we discuss the unique design and operational characteristics required for the flight model of the DIF probe.

ISSN:0034-6748    

DOI:10.1063/1.1138441

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A diamond anvil type high‐pressure cell for a low‐temperature experiment with an optical system is described. The diamond anvil type pressure cell is actuated by helium gas in the cryostat at low temperatures. The optical system is for the pressure calibration at low temperatures by the use of the ruby fluorescence method and forinsitudirect observation of the sample at low temperatures. A pressure more than 40 GPa has been continuously generated and the pressure is determinedinsituby the ruby scale with an accuracy of 0.3 below 35 GPa and 0.6 above 35 GPa.

ISSN:0034-6748    

DOI:10.1063/1.1138442

出版商:AIP    

年代:1985

数据来源: AIP

摘要:

A microwave apparatus for phase boundary determinations of corrosive fluid mixtures to 1.7 kbar and 588 K is described. The apparatus measures shifts in a static microwave energy field caused by changes in sample dielectric properties. The measured interactions involve the entire sample cell; sample volumes are small (∼25 cm3); phase transitions are measured directly. Details of the microwave apparatus and the microwave technique are discussed. Data are presented for pure fluids and for an acid‐gas/heavy oil mixture that demonstrate the performance of the apparatus.

ISSN:0034-6748    

DOI:10.1063/1.1138443

出版商:AIP    

年代:1985

数据来源: AIP