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Jan 1996

Volume 67, Issue 1, pp. 1-334

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Analytical thermal lens instrumentation

Mladen Franko and Chieu D. Tran

Rev. Sci. Instrum. 67, 1 (1996); http://dx.doi.org/10.1063/1.1147512 (18 pages) | Cited 134 times

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This review describes recent instrumentation developments of the thermal lens techniques. It will begin with a brief discussion of the theory of the techniques. Its main focus is, however, on the detail description of various instruments. Specifically, the discussion will begin with the description of single beam instruments which were initially developed following by dual beam instruments. Elaboration will be focused on some of the most sophisticated instruments which were developed recently. These include differential thermal lens instruments, multiwavelength and spectral tunable instruments, circular dichroism spectropolarimeters, rotoreflecting instruments, and miniaturized thermal lens instruments. Selection of lasers, focusing, modulation, sample position, sample cells, data acquisition, noise reduction, and applications of acousto‐optic tunable filters will also be discussed. The future of the techniques in terms of instrumentation will be finally forecasted. © 1996 American Institute of Physics.
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07.60.-j Optical instruments and equipment
82.80.Ms Mass spectrometry (including SIMS, multiphoton ionization and resonance ionization mass spectrometry, MALDI)

Photothermal dielectric spectroscopic microscope

Yasuo Cho and Tomoyuki Kumamaru

Rev. Sci. Instrum. 67, 19 (1996); http://dx.doi.org/10.1063/1.1146544 (10 pages) | Cited 5 times

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A new photothermal technique is proposed. It is based on the temperature characteristic of the dielectric constant of light‐irradiated material. When chopped light is absorbed in a dielectric material, an alternating variation of capacitance is caused by the heat produced due to light absorption and is detected by using a frequency demodulation technique. A quantitative derivation is presented for the alternating capacitance variation in terms of the optical, thermal, dielectric, and geometric parameters of the system. The experimental results for lead zirconate titanate ceramics, barium titanate single‐crystal, TiO2–Bi2Ti4O11 ceramics, and ethyl alcohol are shown, where the observed signals agree with theoretical ones very well. © 1996 American Institute of Physics.
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07.60.-j Optical instruments and equipment
77.84.-s Dielectric, piezoelectric, ferroelectric, and antiferroelectric materials
78.20.N- Thermo-optic effects
78.20.nb Photothermal effects

The 3ω technique for measuring dynamic specific heat and thermal conductivity of a liquid or solid

I. K. Moon, Y. H. Jeong, and S. I. Kwun

Rev. Sci. Instrum. 67, 29 (1996); http://dx.doi.org/10.1063/1.1146545 (7 pages) | Cited 45 times

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We show how to measure dynamic specific heat and thermal conductivity of a solid or liquid sample using the 3ω technique, which is an ac‐modulation method where we use a heater simultaneously as the sensor. By varying the width of the heater relative to the thermal decay length, one can choose the proper regime to measure thermal conductivity or specific heat. The technique is applied to window glass and the results confirm the validity of the method. Experimental results for potassium dihydrogen phosphate crystal demonstrate the first‐order transition at the Curie point, and the dynamic specific heat of supercooled liquid potassium–calcium nitrate is shown. © 1996 American Institute of Physics.
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07.20.-n Thermal instruments and apparatus
65.20.-w Thermal properties of liquids
65.40.-b Thermal properties of crystalline solids
65.60.+a Thermal properties of amorphous solids and glasses: heat capacity, thermal expansion, etc.
65.80.-g Thermal properties of small particles, nanocrystals, nanotubes, and other related systems
65.40.gd Entropy

High frequency intensity modulation of a CO2 waveguide laser by mode‐locking techniques

John Tulip and Jean‐Robert Simard

Rev. Sci. Instrum. 67, 36 (1996); http://dx.doi.org/10.1063/1.1146546 (5 pages)

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Mode‐locking techniques are well known for the generation of short pulses. However, little work has been done to evaluate the use of this technique with long wavelength (10.6 μm) CO2 waveguide lasers. For this region of the spectrum, mode locking has the advantage of requiring smaller modulation voltage than other conventional modulation techniques which makes possible the generation of pulses at a frequency higher than 100 MHz. The efficient generation of pulses at these frequencies makes this type of laser attractive for active imaging at long wavelengths. In this paper, the design of a mode‐locked waveguide CO2 laser is reported and its characteristics of operation are compared with an existing model. Significant depth of modulation is observed at 190 MHz with an applied modulation voltage lower than 50 V. From the comparison between the experimental results and the theoretical model, improvements are proposed. © 1996 American Institute of Physics.
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42.55.Lt Gas lasers including excimer and metal-vapor lasers
42.60.Fc Modulation, tuning, and mode locking

A compact frequency domain fluorometer with a directly modulated deuterium light source

C. G. Morgan, Y. Hua, A. K Mitchell, J. G. Murray, and A. D. Boardman

Rev. Sci. Instrum. 67, 41 (1996); http://dx.doi.org/10.1063/1.1147228 (7 pages) | Cited 3 times

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A phase fluorometer based on a low‐cost and versatile high‐frequency modulated light source and a fast gain‐modulated photomultiplier is described. The apparatus is particularly well‐suited to high‐sensitivity frequency‐domain fluorescence measurements requiring ultraviolet excitation. The system is very compact since it features a directly modulated light source, a miniature photomultiplier tube, and an rf synthesizer on a PC board. Equipped with a suitable fiber optic probe sensor, the device has potential as a portable unit for a wide range of remote sensing applications. The lamp can be modulated at frequencies up to 120 MHz and the phase fluorometer has been tested at up to 70 MHz with a range of fluorescent lifetime standards containing quinine sulfate quenched with sodium chloride. © 1996 American Institute of Physics.
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07.57.-c Infrared, submillimeter wave, microwave and radiowave instruments and equipment
07.60.-j Optical instruments and equipment
78.47.-p Spectroscopy of solid state dynamics

The method of fluorescence decays simultaneous analysis

Vladimir V. Apanasovich and Eugene G. Novikov

Rev. Sci. Instrum. 67, 48 (1996); http://dx.doi.org/10.1063/1.1147226 (7 pages) | Cited 3 times

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A new method of high speed simultaneous deconvolution of multiple fluorescence decays with equal lifetimes and variable amplitudes is offered. The absence of need for initial guesses and comparably high accuracy make it suitable for obtaining initial conditions for other methods like iterative least squares. We discuss optimizations of the deconvolution procedure based on reductions of the matrix dimension. This establishes a higher processing speed and requires less computer memory. The properties and potential of this method were investigated through tests on simulated decay surfaces. © 1996 American Institute of Physics.
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07.57.-c Infrared, submillimeter wave, microwave and radiowave instruments and equipment
07.60.-j Optical instruments and equipment

Actively quenched single‐photon avalanche diode for high repetition rate time‐gated photon counting

A. Spinelli, L. M. Davis, and H. Dautet

Rev. Sci. Instrum. 67, 55 (1996); http://dx.doi.org/10.1063/1.1146551 (7 pages) | Cited 18 times

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This paper reports an experimental characterization of the EG&G SPCM‐AQ single‐photon avalanche diode module with an active quenching bias circuit that gives a dead time of ∼35 ns for use in high count rate, fast timing applications. A quantum efficiency of ≳70% and an optimal timing jitter with a full width at one‐thousandth maximum of 1.5 ns is obtained if the light is tightly focused to a spot of <25 μm in the center of the active region, if the signal from the diode before the active quenching circuitry is used as input to the timing electronics, and if an external dead time of ∼55 ns is imposed. Under these conditions, the total probability of obtaining an afterpulse is found to be ∼2×10−3. Limitations of existing time‐correlated single‐photon counting instrumentation for count rates exceeding 106 s−1 are discussed. © 1996 American Institute of Physics.
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85.60.Dw Photodiodes; phototransistors; photoresistors

A comparison of an elliptical multipole wiggler and crystal optics for the production of circularly polarized x rays

J. C. Lang, George Srajer, and Roger J. Dejus

Rev. Sci. Instrum. 67, 62 (1996); http://dx.doi.org/10.1063/1.1146552 (6 pages) | Cited 1 time

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We have compared the circularly polarized x‐ray flux obtained from an elliptical multipole wiggler to that obtained from a planar undulator combined with phase retarding crystal optics. This comparison is carried out for low (3.5–13 keV) and high (50–100 keV) x‐ray energies. For both these energy regimes, we demonstrate that phase retarding crystal optics are not only a viable alternative to specialized insertion devices but in some cases provide a superior source of circularly polarized x rays. © 1996 American Institute of Physics.
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07.85.Fv X- and γ-ray sources, mirrors, gratings, and detectors
41.50.+h X-ray beams and x-ray optics

An interleaved comb ion deflection gate for m/z selection in time‐of‐flight mass spectrometry

Paul R. Vlasak, Douglas J. Beussman, Michael R. Davenport, and Christie G. Enke

Rev. Sci. Instrum. 67, 68 (1996); http://dx.doi.org/10.1063/1.1146553 (5 pages) | Cited 34 times

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Modulation of an ion beam is crucial to several applications in time‐of‐flight (TOF) mass spectrometry, especially for tandem TOF instruments which require selection of a particular precursor m/z (mass to charge) value prior to fragmentation. Here we present a detailed description of an ‘‘interleaved comb’’ ion deflection gate device with suitable electronics which offers a performance advantage over the more commonly used deflection plate devices. We demonstrate unit mass resolution for selection to m/z 167 in the tandem TOF instrument constructed in our laboratory. Calculations suggest that the real time of unit resolution for our experimental arrangement is greater than 300. © 1996 American Institute of Physics.
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07.75.+h Mass spectrometers
41.85.Ct Particle beam shaping, beam splitting

Resonance frequency estimation of a bridged loop‐gap resonator used for magnetic resonance measurements

Hiroshi Hirata and Mitsuhiro Ono

Rev. Sci. Instrum. 67, 73 (1996); http://dx.doi.org/10.1063/1.1146554 (6 pages) | Cited 20 times

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This paper presents a method for estimating the resonance frequency of a bridged loop‐gap resonator (BLGR). It first describes the structure of the BLGR and its equivalent electrical circuit, and then a procedure for calculating the resonance frequency is revealed. In this procedure, node analysis, which is a circuit theory, is applied to calculate the branch voltages of the equivalent circuit. Finally, this paper reports on the calculations and measurements of the resonance frequency, and the validity of the method for estimating resonance frequency. © 1996 American Institute of Physics.
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07.57.Pt Submillimeter wave, microwave and radiowave spectrometers; magnetic resonance spectrometers, auxiliary equipment, and techniques

Description and performance of a highly versatile, low‐cost fiber‐optic confocal Raman microscope

C. M. Stellman, K. S. Booksh, J. E. Reddic, and M. L. Myrick

Rev. Sci. Instrum. 67, 79 (1996); http://dx.doi.org/10.1063/1.1146555 (6 pages)

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A versatile fiber‐optic confocal Raman microscope has been developed. Fiber optics provide remote capabilities for the microscope and the ability to use multiple excitation sources and detection schemes. The horizontal and vertical resolutions of the instrument have been determined by monitoring spectral changes while scanning known interfaces and microparticles. The mini‐ mum detectable particle size has been determined via the spectroscopic analysis of calibrated polystyrene microspheres. The horizontal resolution has additionally been tested in the imaging of a 10 μm glass fiber embedded in an epoxy matrix. © 1996 American Institute of Physics.
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07.60.Vg Fiber-optic instruments

A technique for mapping three‐dimensional number densities of species in laser produced plumes

R. A. Al‐Wazzan, C. L. S. Lewis, and T. Morrow

Rev. Sci. Instrum. 67, 85 (1996); http://dx.doi.org/10.1063/1.1146556 (4 pages) | Cited 12 times

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The potential of a diagnostic technique to provide quantitative three‐dimensional (3D) density distributions of species in a low temperature laser‐produced plume is shown. An expanded, short pulse, tunable dye laser is used to probe the plume at a set time during the expansion. Simultaneous recording of two‐dimensional in‐line absorbance maps and orthogonal recording of laser induced fluorescence permits the 3D density mapping by scanning the dye laser frequency. Preliminary data, supported by a simple model, is presented for the case of Ba II ions in a YBCO plume heated by a KrF laser. © 1996 American Institute of Physics.
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52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.77.Bn Etching and cleaning
52.77.Dq Plasma-based ion implantation and deposition

High resolution low dose scattered gamma‐ray tomography

R. S. Thoe

Rev. Sci. Instrum. 67, 89 (1996); http://dx.doi.org/10.1063/1.1146557 (13 pages) | Cited 2 times

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This paper discusses a technique which uses Compton scattered gamma radiation to obtain high contrast, highly spatially resolved, three‐dimensional images in optically opaque objects. A highly desirable property of this technology is that this method allows the acquisition of radiographs without the necessity of placing the object between the source and detector. This paper describes a prototype apparatus which is capable of obtaining images with a spatial resolution of about 1 mm at a depth of 25 mm in steel of normal density with the source and detector both on the same side of the object. Some modeling calculations, reconstruction algorithms, and data verifying the performance of this technique will be presented as well as details of how the efficiency and throughput of this system could be increased by over two orders of magnitude. © 1996 American Institute of Physics.
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07.85.-m X- and γ-ray instruments
42.30.Wb Image reconstruction; tomography

Sensor measurement and experimental control in nuclear magnetic resonance imaging

Derrick P. Green, Bruce J. Balcom, and Thomas J. Lees

Rev. Sci. Instrum. 67, 102 (1996); http://dx.doi.org/10.1063/1.1147585 (6 pages) | Cited 2 times

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A dual purpose sensor acquisition and experimental control system which functions in the demanding environment of a nuclear magnetic resonance imaging (NMRI) spectrometer is described. The system ensures accurate sensor readings during imaging and protects sensitive electronic equipment from the effects of the intense radio frequency pulses and magnetic field gradient switches in NMRI. A homebuilt isolation network was constructed with isolation transformers and optoisolators. A variety of hardware and software methods are implemented to ensure accurate sensor data. The system also allows for the ready incorporation of external events into the NMRI pulse sequence. LabVIEWTM, a graphical programming environment, is the heart of our acquisition/control system. LabVIEW’s graphical interface and modular design enables flexible programs to be constructed which are easily understood and modified by the user. Applications of the system, monitoring photopolymerization and controlling ultrasonic cavitation in conjunction with NMRI, are outlined. © 1996 American Institute of Physics.
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07.57.Pt Submillimeter wave, microwave and radiowave spectrometers; magnetic resonance spectrometers, auxiliary equipment, and techniques
76.60.Pc NMR imaging

Adjustable nanofabricated atomic size contacts

J. M. van Ruitenbeek, A. Alvarez, I. Piñeyro, C. Grahmann, P. Joyez, M. H. Devoret, D. Esteve, and C. Urbina

Rev. Sci. Instrum. 67, 108 (1996); http://dx.doi.org/10.1063/1.1146558 (4 pages) | Cited 101 times

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Metallic point contacts and tunnel junctions with a small and adjustable number of conduction channels have been obtained in the last few years using scanning tunneling microscope and break junction techniques. For conventional break junctions, the reported drift of the interelectrode spacing in the tunnel regime is typically of the order of 0.5 pm/min (1 pm=10−12 m). We have nanofabricated break junctions which display a drift smaller than 0.2 pm/h. The improvement results from the scaling down by two orders of magnitude of the device dimensions. We describe the nanofabrication process, which can be adapted to most metals. We have performed measurements on Al, Cu, and Nb devices. The results illustrate the ability of the technique to explore phenomenalike conductance quantization and two level fluctuations. These new adjustable atomic size contacts and tunnel junctions can be integrated in complex circuits. © 1996 American Institute of Physics.
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73.40.Jn Metal-to-metal contacts
74.45.+c Proximity effects; Andreev reflection; SN and SNS junctions
81.07.-b Nanoscale materials and structures: fabrication and characterization
81.16.-c Methods of micro- and nanofabrication and processing
85.35.-p Nanoelectronic devices

Micromachined infrared sensors using tunneling displacement transducers

T. W. Kenny, J. K. Reynolds, J. A. Podosek, E. C. Vote, L. M. Miller, H. K. Rockstad, and W. J. Kaiser

Rev. Sci. Instrum. 67, 112 (1996); http://dx.doi.org/10.1063/1.1146559 (17 pages) | Cited 18 times

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Uncooled infrared sensors are important for a number of technological and scientific measurements. We have designed, built, and tested a new uncooled infrared sensor which is made by silicon micromachining. This infrared sensor uses a tunneling displacement transducer to detect the thermal expansion of a small volume of trapped gas. Prototype devices based on this design have been operated with NEP better than 3×10−10 W/√Hz at 25 Hz, which is competitive with the best comparably sized uncooled sensors available. This article will describe the design, fabrication, and operation of all elements of this sensor. © 1996 American Institute of Physics.
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07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
85.60.Gz Photodetectors (including infrared and CCD detectors)

Cryogenic linear ion trap for accurate spectroscopy

M. E. Poitzsch, J. C. Bergquist, W. M. Itano, and D. J. Wineland

Rev. Sci. Instrum. 67, 129 (1996); http://dx.doi.org/10.1063/1.1146560 (6 pages) | Cited 16 times

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We have observed linear ‘‘crystals’’ of up to tens of laser‐cooled 199Hg+ ions in a linear rf ion trap. The trap operates at liquid‐He temperature and is designed for use as a prototype 40.5 GHz frequency standard with high accuracy and stability. © 1996 American Institute of Physics.
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06.20.F- Units and standards
37.10.De Atom cooling methods
37.10.Gh Atom traps and guides

An apparatus for multiparametric studies of ion–surface collisions

V. A. Esaulov, O. Grizzi, L. Guillemot, M. Huels, S. Lacombe, and Vu Ngoc Tuan

Rev. Sci. Instrum. 67, 135 (1996); http://dx.doi.org/10.1063/1.1146561 (10 pages) | Cited 22 times

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This paper describes the design and tests of an ultrahigh vacuum apparatus built for the study of particle surface interactions, with emphasis on ion scattering experiments. The system was designed to provide facilities for angle resolved electron spectroscopy, ion scattering spectroscopy (ISS), Auger electron spectroscopy (AES), and ultraviolet photoelectron spectroscopy (UPS). It has provisions for photon spectroscopy and fixed angle time‐of‐flight (TOF) scattering and recoiling spectrometry. Mass selected ion beams in the energy range from a few eV to a few keV can be produced in a continuous or pulsed mode. Two independent, parallel plate tandem electrostatic analyzers, which can rotate around the sample are employed. The angular range spanned is analysis‐type dependent and varies from 0° to 135°. One of the analyzers was designed for low energy secondary electron spectroscopy (0–100 eV) and the other one for ISS and AES measurements in the energy range from a few eV to 5 keV. The system disposes of a Czerny–Turner monochromator for optical spectroscopy in the visible. TOF analysis can be performed for 7° and 38° scattering angles and a flight length of 2.2 m. Alternatively, a large area detector set at 20 cm from the collision center allows TOF and charge fraction measurements over an angular range from 0° to 110°. We describe various tests of the different components of the apparatus and some results of experiments on ion scattering. © 1996 American Institute of Physics.
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07.81.+a Electron and ion spectrometers
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces

Effect of local electric fields on microchannel plate detection of incident 20 keV protons

H. O. Funsten, D. M. Suszcynsky, R. W. Harper, J. E. Nordholt, and B. L. Barraclough

Rev. Sci. Instrum. 67, 145 (1996); http://dx.doi.org/10.1063/1.1146562 (10 pages) | Cited 8 times

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We present data demonstrating the influence of an applied electric field E oriented normal to the input surface of a microchannel plate (MCP) detector on the critical operating parameters of the detector, including the quantum detection efficiency, the spatial resolution, and pulse height distribution. The MCP detector response is characterized using 20 keV protons as the primary radiation. An applied electric field E<−4 V/mm, where a negative value of E corresponds to a nearby object that is biased positive relative to the input surface, results in a high spatial resolution and a quantum detection efficiency that is approximately equal to the open area ratio of the MCP. An electric field −1<E<5 V/mm results in low spatial resolution, in which up to 32% of the measured signal appears as a localized noise that extends several millimeters from the point of ion impact, and a maximum quantum detection efficiency of approximately 0.87. Furthermore, a separate peak in the pulse‐height distribution arises from ions striking the web of the MCP detector and has a much lower pulse magnitude than that of ions striking channels. For E≳5 V/mm, the spatial resolution increases, and the quantum detection efficiency slightly decreases from its maximum value with increasing E. The characteristics of each of these electric field configurations are analyzed in the context of the yield and transport of secondary electrons created at the web of the MCP detector, and the results can be scaled to other ions and energies according to the secondary electron yield of ions striking the web. © 1996 American Institute of Physics.
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29.40.Gx Tracking and position-sensitive detectors

Volume scaling and magnetic field scaling on SC‐ECRIS at MSU‐NSCL

S. Gammino, G. Ciavola, T. Antaya, and K. Harrison

Rev. Sci. Instrum. 67, 155 (1996); http://dx.doi.org/10.1063/1.1146563 (6 pages) | Cited 8 times

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The application of the high B mode concept has allowed an effective upgrading of the superconducting electron cyclotron resonance (ECR) ion source SC‐ECRIS, which is now one of the best operating ECR ion sources in the world in terms of highly charged ion production. To increase the high charge state intensities and the total extracted current we tried to enlarge the plasma volume, but no clear evidence of volume effects was substantially achieved. We also tried to increase the magnetic field of the trap. The theory which led to these experiments is outlined in the following along with the results of tests using larger plasma volumes and tests with larger magnetic field. Even if the theoretical basis is not always well established, the beneficial effect of magnetic field enhancement on ECR source performances is confirmed. The capability of superconducting ECR ion sources to get higher results with respect to room temperature source by means of a higher and variable hexapolar field is underlined. © 1996 American Institute of Physics.
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07.77.Ka Charged-particle beam sources and detectors
52.50.Gj Plasma heating by particle beams

Computer controlled high‐voltage injector

F. Constantin, M. Dumitru, and G. Korschinek

Rev. Sci. Instrum. 67, 161 (1996); http://dx.doi.org/10.1063/1.1146564 (4 pages)

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This paper reports the results of the operation, under active computer control, of a high‐voltage (400 kV) injector. The automation system uses a microcomputer placed on the high‐voltage deck of the ion source, which takes over some of the process control decisions, and a master IBM‐PC at ground potential. Various ion beams (p, H+2, H+3, d, He+, He2+) have been produced, proving the reliability of the system. A maximum value of 460 kV accelerating potential has been reached during the tests. The beam fulfills the requirements for the operation of a room‐temperature IH linac. By using a modular expandable computer system the acceleration voltage is continuously adjusted keeping its standard error within 0.1%. A future enlargement of the injector has been taken into account and the upgrading of the control system for an electron cyclotron resonance ion source would be very simple. © 1996 American Institute of Physics.
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07.05.Dz Control systems
29.25.Ni Ion sources: positive and negative

Polarization reversal of stored proton beams in the Indiana Cooler

B. von Przewoski, W. A. Dezarn, J. Doskow, J. G. Hardie, H. O. Meyer, R. E. Pollock, T. Rinckel, F. Sperisen, W. Haeberli, B. Lorentz, F. Rathmann, T. Wise, and P. V. Pancella

Rev. Sci. Instrum. 67, 165 (1996); http://dx.doi.org/10.1063/1.1146565 (5 pages) | Cited 15 times

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A spin flipper of reliable and robust long‐term operation was developed and has been used successfully at the Indiana University Cooler Storage Ring. To reverse the polarization of the stored beam, the frequency of a rf solenoid is swept adiabatically across a depolarizing resonance frequency. Depolarizing sidebands to the resonance are eliminated by shorting out the ring’s bunching rf cavity prior to the frequency sweep. With the spin flipper it is no longer necessary to dump the stored beam and to refill the ring with protons of opposite spin state. Rather, beam accumulation continues without reversing the spin at injection, and instead the polarization of the stored beam is flipped periodically. Thus the luminosity is significantly increased when the flipper is used. © 1996 American Institute of Physics.
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29.20.db Storage rings and colliders
29.27.Hj Polarized beams

Moiré deflectometry diagnostic for transient plasma, using a multipulse N2 laser

B. Moosman, V. M. Bystritskii, C. J. Boswell, and F. J. Wessel

Rev. Sci. Instrum. 67, 170 (1996); http://dx.doi.org/10.1063/1.1146566 (8 pages) | Cited 7 times

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We have designed a multipulse laser system to measure nanosecond time scale, plasma‐density gradients by moiré deflectometry. The complete system consists of four, transverse‐excited, atmospheric pressure (TEA) N2 laser oscillators and two low‐pressure N2 laser amplifiers; two oscillator pulses are injected into a single amplifier. The amplified pulses are less than 1 ns in duration, with a variable, interpulse time of 4–10 ns. As described here, two TEA oscillators and a single amplifier were used to image air‐density gradients in an expanding, air‐shock wave produced by a spark discharge. © 1996 American Institute of Physics.
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52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.80.Mg Arcs; sparks; lightning; atmospheric electricity

High‐speed surface temperature measurements on plasma facing materials for fusion applications

Masanori Araki and Masanobu Kobayashi

Rev. Sci. Instrum. 67, 178 (1996); http://dx.doi.org/10.1063/1.1146567 (7 pages) | Cited 4 times

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For the lifetime evaluation of plasma facing materials in fusion experimental machines, it is essential to investigate their surface behavior and their temperature responses during an off‐normal event such as the plasma disruptions. An infrared thermometer with a sampling speed as fast as 1×10−6 s/data, namely, the high‐speed infrared thermometer (HSIR), has been developed by the National Research Laboratory of Metrology in Japan. To evaluate an applicability of the newly developed HSIR on the surface temperature measurement of plasma facing materials, high heat flux beam irradiation experiments have been performed with three different materials under the surface heat fluxes up to 170 MW/m2 for 0.04 s in a hydrogen ion beam test facility at the Japan Atomic Energy Research Institute. As for the results, HSIR can be applicable for measuring the surface temperature responses of the armor tile materials with a little modification. It is also confirmed that surface temperatures measured with the HSIR thermometer show good agreement with the analytical results for stainless steel and carbon based materials at a temperature range of up to 2500 °C. However, for aluminum the HSIR could measure the temperature of the high dense vapor cloud which was produced during the heating due to lower melting temperature. Based on the result, a multichannel arrayed HSIR thermometer has been designed and fabricated. © 1996 American Institute of Physics.
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07.20.Ka High-temperature instrumentation; pyrometers
28.52.Lf Components and instrumentation

Electrical single probe with an automatic positioner

R. López, L. Meléndez, A. M. Sánchez, E. Gaytán, E. Chávez, R. Valencia, G. Cruz, M. G. Olayo, and A. Flores

Rev. Sci. Instrum. 67, 185 (1996); http://dx.doi.org/10.1063/1.1146568 (3 pages) | Cited 1 time

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An easy to assemble and inexpensive plasma diagnostic system is presented. An electrical single probe and its vacuum and electrical isolation arrangement, integrated to an automatic positioner device, has been constructed and tested in plasma environments. This system provides a more precise estimation of the probe electrode position than others previously proposed in the literature. To control the probe electrode position an electronic circuit based in a microcontroller device is used. This automatic positioner avoids the troubles related to a manual operation. © 1996 American Institute of Physics.
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06.60.Sx Positioning and alignment; manipulating, remote handling
52.70.Ds Electric and magnetic measurements
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