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Dec 2005

Volume 76, Issue 12, Articles (12xxxx)

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Optical absorption spectrum measurement of films at a low temperature using photothermal bending spectroscopy

Hitoe Habuchi and Daisuke Harada

Rev. Sci. Instrum. 76, 123907 (2005); http://dx.doi.org/10.1063/1.2149148 (4 pages)

Online Publication Date: 27 December 2005

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The optical absorption spectrum of a semiconductor film was obtained at a low temperature using an optical cantilever method called photothermal bending spectroscopy. The film, clamped on one side in a cryostat, was uniformly cooled with nitrogen gas. The product of the measurable optical absorption coefficient and the thickness of the film was better than 1×10−3 at 110 K. We demonstrated that the 1.74 eV peak in the optical absorption spectrum of a C60 film could not be observed at room temperature, but could be observed at 110 K due to a sharpening of the Urbach tail slope.
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78.66.Tr Fullerenes and related materials
78.40.Ri Fullerenes and related materials
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)
82.80.Kq Energy-conversion spectro-analytical methods (e.g., photoacoustic, photothermal, and optogalvanic spectroscopic methods)
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Design and characterization of late-mixing flash pyrolytic reactor molecular-beam source

Hahkjoon Kim, Kristin S. Dooley, Elizabeth R. Johnson, and Simon W. North

Rev. Sci. Instrum. 76, 124101 (2005); http://dx.doi.org/10.1063/1.2148991 (3 pages) | Cited 10 times

Online Publication Date: 14 December 2005

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We report on the design and characterization of an intense pulsed beam source for the generation of expansion-cooled radical species. The source combines both dual pulsed valve late mixing for coexpansion of reactive gases with a pyrolytic end nozzle as a flash kinetic reactor. As a demonstration of the source we present evidence of BrO and ClO radical production and subsequent photodissociation studies of these species using velocity map ion imaging. The radicals are characterized by a rotational temperature of 150±40 K although substantially lower temperatures should be possible.
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07.77.Gx Atomic and molecular beam sources and detectors
82.30.Lp Decomposition reactions (pyrolysis, dissociation, and fragmentation)
82.50.-m Photochemistry
82.30.Cf Atom and radical reactions; chain reactions; molecule-molecule reactions

Heated quartz microbalance to study thermally deposited calcareous scale

C. Gabrielli, H. Perrot, P. Rousseau, A. Belghazi, T. Chevrot, J. M. Colin, and C. Simonet

Rev. Sci. Instrum. 76, 124102 (2005); http://dx.doi.org/10.1063/1.2126573 (9 pages) | Cited 1 time

Online Publication Date: 21 December 2005

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The scaling effect can affect drastically all equipment where water is used. In general, the phenomenon is amplified with hot fluids or hot pipes as, for example, conditions found in the heat exchangers. Thus, dramatic damages can occur that lead to dangerous economic consequences. The basic idea in this article is to promote the development of tools that can characterize the scaling power under certain conditions. A sophisticated heated quartz crystal microbalance was built and its performance was evaluated. It was shown that the scale must be deposited onto the sensor surface in an identic way compared with current scaling deposition conditions and the kinetics of deposition evaluated thanks to the microbalance response.
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07.10.Lw Balance systems, tensile machines, etc.
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
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Instrumentation for video-rate near-infrared diffuse optical tomography

Daqing Piao, Hamid Dehghani, Shudong Jiang, Subhadra Srinivasan, and Brian W. Pogue

Rev. Sci. Instrum. 76, 124301 (2005); http://dx.doi.org/10.1063/1.2149147 (13 pages) | Cited 11 times

Online Publication Date: 21 December 2005

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This article describes the design, rationale, and system performance of a rapid imaging near-infrared diffuse optical tomography system that is capable of collecting tomographic measurements at video rate. Data-acquisition speed of 35 frames/s is achieved by spectral encoding of the sources, followed by spectral decoding of all detection channels in parallel in a spectrometer and using charge-coupled-device (CCD)-based detection. The combination of spectral decoding of the source lights horizontally in a spectrometer and spatial separation of the detector positions vertically at the entrance slit provides separate data for the entire set of source-detector pairs which can be acquired at the frame rate of the CCD camera. The described system features eight sources at an overall 785 nm center band with an average of 1.25 nm spacing in wavelength and eight detectors evenly deployed in a 27 mm array designed for imaging with small animal tissues. The system performs with localization error of 2.5 mm, and absorption recovering uncertainty of 16.7%. The point spread function of the imaging is estimated to be 4.1 mm when near to the edge and 10.4 mm at the center of the imaging array. Capture of transient changes of absorption coefficient in a dynamic phantom are also presented.
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87.63.L- Visual imaging
87.56.Da Ancillary equipment
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Development of a simulator of a satellite-to-satellite interferometer for determination of the Earth’s gravity field

Shigeo Nagano, Mizuhiko Hosokawa, Hiroo Kunimori, Taizoh Yoshino, Seiji Kawamura, Masashi Ohkawa, and Takashi Sato

Rev. Sci. Instrum. 76, 124501 (2005); http://dx.doi.org/10.1063/1.2140280 (10 pages) | Cited 1 time

Online Publication Date: 14 December 2005

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A satellite-to-satellite laser interferometer is essential for a future gravity-field mission to improve the accuracy and spatial resolution of the Earth’s gravity model. We have designed a ground-based simulator of a satellite-to-satellite interferometer, which aims to evaluate instrument error reflecting on the accuracy of the gravity-field retrieval and achieve the essential technologies required to measure the intersatellite range rate. The developed simulator was successfully operated with a range-rate sensitivity of 40 nm/s/math in the measurement band of 10−2–1 Hz. From a primary demonstration, it was confirmed to be available for experimental simulation of the satellite-to-satellite interferometer in the laboratory. The simulator will be a powerful tool for establishing guidelines for the development of future gravity missions.
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91.10.Pp Geodetic techniques; gravimetric measurements and instruments
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Theoretical and experimental behavior of a compact magnetically insulated line oscillator electromagnetic structure

Richard Cousin, Jean Larour, Pierre Raymond, Joseph Wey, Philippe Gouard, and Alain Joseph Durand

Rev. Sci. Instrum. 76, 124701 (2005); http://dx.doi.org/10.1063/1.2141004 (8 pages) | Cited 13 times

Online Publication Date: 21 December 2005

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The magnetically insulated line oscillator (MILO) is a high power microwave source capable of delivering output powers greater than 1 GW at a frequency of several gigahertz. The device is a crossed electric and magnetic field oscillator without any external structure to establish the static magnetic field, required to guide the electron beam, thus making it compact. We report on a compact MILO device based on the U.S. Air-Force design where all dimensions are reduced by a factor of 2. All the key points are reviewed using the Electromagnetic-PIC (Particle-In-Cell) code MAGIC in two-dimensional geometry. The operating frequency of such a device is 2.44 GHz, leading to an output power slightly above 1 GW for an operating voltage of 500 kV and a maximum current of 45 kA. The output power can be increased up to 2 GW by optimizing the output coupling and reducing the beam loading effect. The analysis of the compact electromagnetic structure is based on the calculation of the external Q factor (Qext). The Qext coefficient is calculated for each resonant frequency of the four-cell coupled periodic resonator which accounts for the main part of the MILO slow wave structure. The optimized geometrical parameters such as the extractor vane radius (Rext = 47 mm) and the collector length (Lcol = 92 mm), which constitutes the output coupling section, lead to a maximum of simulated output power. A prototype has been built according to this geometry. The compact MILO structure is characterized by some cold tests (without electron beam) injecting a low rf power by a network analyzer; experimental results are presented and discussed in comparison with the simulation.
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84.30.Ng Oscillators, pulse generators, and function generators
84.40.Dc Microwave circuits
85.70.-w Magnetic devices
41.20.-q Applied classical electromagnetism
02.40.-k Geometry, differential geometry, and topology

A cryogenic voltage amplifier with 36 MHz bandwidth using discrete GaAs metal-semiconductor field-effect transistors

B. H. Hu and C. H. Yang

Rev. Sci. Instrum. 76, 124702 (2005); http://dx.doi.org/10.1063/1.2140224 (4 pages) | Cited 1 time

Online Publication Date: 27 December 2005

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We report a design procedure and performance of a voltage amplifier using commercially available GaAs metal-semiconductor field-effect transistors. There are two stages: a common-source amplifier that provides a moderate gain, followed by a common-drain stage for driving the 50 Ω coaxial cable. The overall voltage gain measured at 4.2 K with a 50 Ω load is 3.3, with a bandwidth of 36 MHz. The input-referred voltage noise is measured to be approximately 3.2 nV/√Hz in a wide frequency range.
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84.30.Le Amplifiers
85.30.Tv Field effect devices

Design and performance of sliced-aperture corrugated feed horn antennas

J. Singal, E. Wollack, A. Kogut, M. Limon, P. Mirel, P. Lubin, and M. Seiffert

Rev. Sci. Instrum. 76, 124703 (2005); http://dx.doi.org/10.1063/1.2148990 (4 pages) | Cited 4 times

Online Publication Date: 27 December 2005

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We report on the design of corrugated feed horn microwave antennas at 3.3, 5.6, 7.8, and 10.2 GHz for the absolute radiometer for cosmology, astrophysics, and diffuse emission experiment. These horns have low sidelobe symmetrical beams with 12° full width at half power, and three noteworthy features: a 30° slice at the aperture, a profiled rather than a linear taper, and a slowly varying groove depth along the length of the horn. The profiled taper and varying groove depth provided a narrow beam given the existing physical spatial constraints of the instrument in which the horns are used. The 30° slice was necessary for instrumental considerations and has a minimal effect on the symmetry of the beam. The slice reduces the effective aperture radius and overall length to that corresponding to an unsliced horn with an aperture at roughly the middle of the slice and does not introduce any undesirable effects.
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84.40.Ba Antennas: theory, components and accessories
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
95.55.Jz Radio telescopes and instrumentation; heterodyne receivers
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Calibration of a thermocouple for measurement of oscillating temperature

Yusuke Tashiro, Tetushi Biwa, and Taichi Yazaki

Rev. Sci. Instrum. 76, 124901 (2005); http://dx.doi.org/10.1063/1.2140489 (5 pages) | Cited 4 times

Online Publication Date: 14 December 2005

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We report on the dynamic calibration of a thermocouple for the measurement of the oscillating temperature. Temperature oscillation is induced in a gas-filled tube by a periodically forced pressure oscillation and measured by a thermocouple. The radial profile of the measured temperature oscillations is compared with the theoretical one, which is determined from the simultaneously measured pressure. A response function of the thermocouple is obtained from the difference in amplitude and phase angle between them by varying the diameter of the thermocouple, oscillating frequency, tube radius, and working gas. We can obtain a true temperature oscillation by using the response function given in this experiment.
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43.20.+g General linear acoustics
43.58.+z Acoustical measurements and instrumentation

1ω, 2ω, and 3ω methods for measurements of thermal properties

Chris Dames and Gang Chen

Rev. Sci. Instrum. 76, 124902 (2005); http://dx.doi.org/10.1063/1.2130718 (14 pages) | Cited 49 times

Online Publication Date: 21 December 2005

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3ω methods are commonly used to measure the thermal conductivity of a substrate adjacent to a strip heater or the thermal conductivity and specific heat of a suspended wire. Here we consider the general case of a line heater that is also used to sense temperature. Analysis of all harmonics is presented in terms of generic thermal and electrical transfer functions and is readily adapted to other experimental configurations. We identify voltage signals at 2ω and 1ω that contain the same information about the thermal properties as the 3ω signal. The 2ω voltage requires a dc offset at the current source. The 1ω voltage requires a very stable current source, but eliminates the need for higher-harmonic detection, and is advantageous for studying the dynamics of systems with very fast thermal response times. The 1ω, 2ω, and 3ω methods compare favorably with experiments using a suspended platinum wire and a line heater on a Pyrex substrate. With a modern lock-in amplifier, no common-mode voltage subtraction is necessary, which simplifies the experiment compared to the common practice of balancing a bridge or using a multiplying digital-to-analog converter. We also show that the widespread practice of using a voltage source to approximate a current source is only valid when the sample resistance is small compared to the total electrical resistance of the circuit, and derive and experimentally verify a correction factor to be used otherwise.
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07.20.-n Thermal instruments and apparatus
72.15.Eb Electrical and thermal conduction in crystalline metals and alloys

Automatic procedure for the correction of thermoelastic stress analysis data acquired in nonadiabatic conditions

A. Gallotti and A. Salerno

Rev. Sci. Instrum. 76, 124903 (2005); http://dx.doi.org/10.1063/1.2140446 (7 pages) | Cited 1 time

Online Publication Date: 29 December 2005

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Thermoelastic stress analysis (TSA), performed on metallic components with a high diffusivity coefficient, seldom reaches adiabatic conditions. As a consequence, TSA results are affected by an attenuation whose entity varies locally, preventing the use of TSA as a reliable quantitative investigation means. The recovery of the adiabatic temperature and of the correct value of the first stress invariant, directly linked to it, can only be performed making an assumption on the local stress distribution. This article presents a method for automatically choosing, among a number of stress distribution functions, the one that performs the best correction of the raw TSA data. The implementation of this automatic correction procedure in a computer program allowed the point-by-point correction of whole TSA images.
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46.80.+j Measurement methods and techniques in continuum mechanics of solids
46.25.Hf Thermoelasticity and electromagnetic elasticity (electroelasticity, magnetoelasticity)
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Characterization system for resonant micro- and nanocantilevers

Rasmus Sandberg, Anja Boisen, and Winnie Svendsen

Rev. Sci. Instrum. 76, 125101 (2005); http://dx.doi.org/10.1063/1.2140284 (6 pages) | Cited 6 times

Online Publication Date: 14 December 2005

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We present a system for characterization of the resonant properties of micro- and nanocantilever sensors. The system has been constructed as a vacuum chamber with capabilities for controlling environmental conditions such as pressure, temperature, and chemical constituents. Characterization can be achieved either electrically or using a specialized laser-optical detection system. The system has been used to characterize the resonant properties of SiO2 cantilevers as well as other resonant structures. We present experimental results of a SiO2 resonant cantilever, showing an exceptional accuracy in resonant frequency determination, and demonstrating the importance of resonance characterization in a controlled environment.
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07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
07.10.Cm Micromechanical devices and systems
07.30.Kf Vacuum chambers, auxiliary apparatus, and materials
46.40.Ff Resonance, damping, and dynamic stability

Microscopic four-point probe based on SU-8 cantilevers

S. Keller, S. Mouaziz, G. Boero, and J. Brugger

Rev. Sci. Instrum. 76, 125102 (2005); http://dx.doi.org/10.1063/1.2140443 (4 pages) | Cited 6 times

Online Publication Date: 14 December 2005

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A microscopic four-point probe (μ4PP) for resistivity measurements on thin films was designed and fabricated using the negative photoresist SU-8 as base material. The device consists of four microscopic cantilevers, each of them supporting a probe tip at the extremity. The high flexibility of SU-8 ensures a stable electrical point contact between samples and probe tip with all four electrodes even on rough surfaces. With the presented surface micromachining process, μ4PPs with a probe-to-probe spacing of 10–20 μm were fabricated. Resistivity measurements on thin Au, Al, and Pt films were performed successfully. The measured sheet resistances differ by less than 5% from those obtained by a commercial macroscopic resistivity meter. Due to the low contact forces (Fcont<10−4 N), the μ4PP is suitable to be applied also to fragile materials such as conducting polymers. Here the authors demonstrate the possibility of performing resistivity measurements on 100-nm-thick pentacene (C22H14) films with a sheet resistance Rs>106 Ω/◻.
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84.37.+q Measurements in electric variables (including voltage, current, resistance, capacitance, inductance, impedance, and admittance, etc.)
07.10.Cm Micromechanical devices and systems
73.61.Ph Polymers; organic compounds
73.61.At Metal and metallic alloys
73.40.-c Electronic transport in interface structures

Microfabricated continuous-flow, turbulent, microsecond mixer

Zigurts K. Majumdar, Jason D. B. Sutin, and Robert M. Clegg

Rev. Sci. Instrum. 76, 125103 (2005); http://dx.doi.org/10.1063/1.2130332 (11 pages) | Cited 4 times

Online Publication Date: 21 December 2005

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We present a microfabricated, continuous-flow, turbulent mixing device that can mix two or more fluids to complete homogeneity on the molecular scale in the microsecond range. The current design is compact, portable, relatively simple to fabricate, adaptable for various measurement techniques, and consumes small sample volumes. The entire mixing process is observable and we use this feature to characterize the dependence of the progress of mixing on the flow velocity. We present details of the mixer’s construction and optical data acquisition using fluorescence. Because the mixer is constructed using microfabrication technology, it is inexpensive and alterations are easy to explore. We show that the dependence of mixing times and pressure drop on the flow velocity agree well with theoretical expectations for turbulent pipe flow. This provides useful guidelines in predicting performance of this type of mixing device.
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85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices

Pulsed laser heating and temperature determination in a diamond anvil cell

S. Deemyad, E. Sterer, C. Barthel, S. Rekhi, J. Tempere, and Isaac F. Silvera

Rev. Sci. Instrum. 76, 125104 (2005); http://dx.doi.org/10.1063/1.2140493 (4 pages) | Cited 12 times

Online Publication Date: 21 December 2005

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Pulsed laser heating in a diamond anvil cell has several advantages over cw heating: it can suppress thermally activated diffusion of the pressurization medium into the gasket and diamond, suppress chemical reactions of impurities with the sample and environment, requires far less average power and thus less heating of the sample environment, and can attain very high temperatures. It was recently shown that it is possible to accurately measure the melting point of platinum and other materials at ambient conditions using a pulsed laser and a simple ungated CCD detector, measuring the time-averaged irradiance. We show that this same technique can be used for high-pressure samples in a diamond anvil cell. As a demonstration, the high-pressure melting curve of iron is reproduced and compared to literature values.
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42.62.Eh Metrological applications; optical frequency synthesizers for precision spectroscopy
64.70.D- Solid-liquid transitions
07.20.Dt Thermometers
07.35.+k High-pressure apparatus; shock tubes; diamond anvil cells

Design of a bidirectional actuator for a nanopositioning system with a permanent magnet and an electromagnet

K. H. Kim and D. G. Gweon

Rev. Sci. Instrum. 76, 125105 (2005); http://dx.doi.org/10.1063/1.2148999 (8 pages) | Cited 2 times

Online Publication Date: 21 December 2005

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A precision bidirectional linear actuator for ultraprecision systems is proposed and designed in this article. The actuator is composed of a symmetric structure with a force generation unit and a guide mechanism. The force generation part consists of a permanent magnet and an electromagnet, which generate a permanent and a reversible flux, respectively. The combination of permanent and reversible fluxes makes various flux densities in its air gaps between the moving part and the fixed yokes. The difference between flux densities in the lower and upper gaps creates forces for bidirectional linear motions of hundreds of micrometers. As a guide mechanism, two circular plates and one shaft are used. Reducing other forces generated by motions, except the z-directional motion, these circular plates in the form of a flexure endow the actuator with smooth motion, freedom from wear, and a high stiffness for a rapid settling time. The function of the shaft is to transfer motion to an object. Finally, the total body has a symmetric structure enabling it to be stable in terms of thermal error. The actuator is designed with the software tools MAXWELL™2D and PRO-MECHANICA™. The designed actuator is evaluated with a linear current amplifier, a laser Doppler vibrometer for nanometer resolution, a dynamic signal analyzer for frequency responses of the proposed actuator, and a simple proportional-integral-derivative controller for its tracking performance.
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89.20.Kk Engineering
85.70.-w Magnetic devices
46.70.De Beams, plates, and shells

Temperature-controlled autocollimator with ultrahigh angular measuring precision

Jie Yuan, Xingwu Long, and Kaiyong Yang

Rev. Sci. Instrum. 76, 125106 (2005); http://dx.doi.org/10.1063/1.2149010 (6 pages) | Cited 8 times

Online Publication Date: 21 December 2005

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A temperature-controlled autocollimator with ultrahigh angular measuring precision is proposed in this article, which is different from our previous publication [J. Yuan and X. W. Long, Rev. Sci. Instrum. 74, 1362 (2003)] . The autocollimator consists of a zoom lens illuminating a charge-coupled device (CCD). This design provides a compact size and increased stability without compromising precision. Moreover, this design makes it possible to detect a target mirror with either plane reflectors or spherical reflectors. Devices for shock absorption and heat insulation were implemented to diminish external interferences. A special temperature-control system for the autocollimator is designed to control the temperature of the autocollimator. The temperature of the autocollimator fluctuates less than ±0.01 °C. The CCD camera’s noise is a fatal obstacle that prevents us from achieving an ultrahigh angular measuring precision. In this article, the influence of the CCD camera’s noise on the measuring resolution is analyzed theoretically in detail. Based on the analysis, some special noise-suppressing methods to eliminate the influence of the CCD camera’s noise are proposed. Both the influence of the CCD camera’s noise and the noise-suppressing methods have not been discussed in our previous publication [J. Yuan and X. W. Long, Rev. Sci. Instrum. 74, 1362 (2003)] . By using the methods mentioned above, the measuring precision of the autocollimator has been greatly improved and the requirements on the external condition have been greatly reduced. The method is proved to be reliable by a prototype experiment. Two-axis angular displacement can be measured simultaneously and a measuring precision of 0.005 arcsec has been achieved, which is currently the highest measuring precision in the world.
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42.79.Ag Apertures, collimators
07.20.-n Thermal instruments and apparatus
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)
42.15.Eq Optical system design

Nanosecond rise time air-core current transformer for long-pulse current measurement in pulsed power

R. Shukla, A. Shyam, S. Chaturvedi, R. Kumar, D. Lathi, V. Chaudhary, R. Verma, K. Debnath, S. Sharma, J. Sonara, K. Shah, and B. Adhikary

Rev. Sci. Instrum. 76, 125107 (2005); http://dx.doi.org/10.1063/1.2149011 (6 pages) | Cited 4 times

Online Publication Date: 27 December 2005

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A slow-wave delay line type air-core (nonmagnetic Nylon former) current transformer fabricated using silver epoxy for the measurement of currents of long pulse durations and few nanoseconds rise times is reported in this article. The advantage of using silver epoxy is that it fills all the voids between coil and shield and enhances the proximity of the coil to the shield, leading to a high value of distributed capacitance. Thus the transit time of the coil increases and it can measure fast current pulses of longer durations. Increasing the inductance of the coil can compensate for the resulting reduction in the sensitivity of the coil for matched termination. An easy experimental technique to find the value of the matched terminating resistor is also reported in this article. We have also done simulations of the slow wave current transformer using PSPICE.
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84.37.+q Measurements in electric variables (including voltage, current, resistance, capacitance, inductance, impedance, and admittance, etc.)
84.32.Hh Inductors and coils; wiring
84.30.-r Electronic circuits

Machine vision for high-precision volume measurement applied to levitated containerless material processing

R. C. Bradshaw, D. P. Schmidt, J. R. Rogers, K. F. Kelton, and R. W. Hyers

Rev. Sci. Instrum. 76, 125108 (2005); http://dx.doi.org/10.1063/1.2140490 (8 pages) | Cited 9 times

Online Publication Date: 29 December 2005

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By combining the best practices in optical dilatometry with numerical methods, a high-speed and high-precision technique has been developed to measure the volume of levitated, containerlessly processed samples with subpixel resolution. Containerless processing provides the ability to study highly reactive materials without the possibility of contamination affecting thermophysical properties. Levitation is a common technique used to isolate a sample as it is being processed. Noncontact optical measurement of thermophysical properties is very important as traditional measuring methods cannot be used. Modern, digitally recorded images require advanced numerical routines to recover the subpixel locations of sample edges and, in turn, produce high-precision measurements.
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06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)

Resonant-cavity approach to noninvasive, pulse-to-pulse emittance measurement

J. S. Kim, C. D. Nantista, R. H. Miller, and A. W. Weidemann

Rev. Sci. Instrum. 76, 125109 (2005); http://dx.doi.org/10.1063/1.2149191 (13 pages)

Online Publication Date: 29 December 2005

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We present a resonant-cavity approach for noninvasive, pulse-to-pulse, beam emittance measurements of noncircular multibunch beams. In a resonant cavity, desired field components can be enhanced up to QLλ/π, where QLλ is the loaded quality factor of the resonant mode λ, when the cavity resonant mode matches the bunch frequency of a bunch-train beam pulse. In particular, a quad cavity, with its quadrupole mode (TM220 for rectangular cavities) at beam operating frequency, rotated 45° with respect to the beamline, extracts the beam quadrupole moment exclusively, utilizing the symmetry of the cavity and some simple networks to suppress common modes. Six successive beam quadrupole-moment measurements, performed at different betatron phases in a linear transport system, determine the beam emittance, i.e., the beam size and shape in the beam’s phase space, if the beam current and position at these points are known. In the presence of x-y beam coupling, ten measurements are required. One measurement alone provides the rms beam size of a large aspect ratio beam. The resolution for such a measurement of rms beam size with the rectangular quad-cavity monitor presented in this article is estimated to be on the order of 10 μm. A prototype quad cavity was fabricated and preliminary beam tests were performed at the Next Linear Collider Test Accelerator at the Stanford Linear Accelerator Center. The results were mainly limited by beam jitter and uncertainty in the beam position measurement at the cavity location. This motivated the development of a position-emittance integrated monitor [ J. S. Kim et al., Rev. Sci. Instrum. 76, 073302 (2005) ].
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29.27.Fh Beam characteristics
29.27.Eg Beam handling; beam transport
41.85.Ct Particle beam shaping, beam splitting
29.20.-c Accelerators
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Closed, heated reaction chamber design for dynamic high-temperature x-ray-diffraction analyses of gas/solid displacement reactions

Michael S. Haluska, Robert L. Snyder, Kenneth H. Sandhage, and Scott T. Misture

Rev. Sci. Instrum. 76, 126101 (2005); http://dx.doi.org/10.1063/1.2136076 (4 pages) | Cited 1 time

Online Publication Date: 14 December 2005

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A closed, x-ray transparent chamber for containing a hot reactive gas (generated from an internal condensed source) has been designed and evaluated for use in dynamic x-ray-diffraction analysis of a gas/solid displacement reaction. The chamber consisted of a square-bottom base and lid machined from dense pyrolytic graphite. The base contained a flat pedestal, upon which SiO2 microshells (the reactant oxide) were placed, raised above adjacent cavities holding Mg flakes (the condensed precursor to the reactive gas). Upon heating to 650 °C, the Mg evaporated and reacted with the SiO2 inside the sealed chamber. By passing incident and diffracted x rays through the vertical side walls of the chamber and by blocking undesired graphite-diffracted x rays with platinum, the Mg(g)/SiO2(s) displacement reaction could be tracked with time. This is the first use of dynamic high-temperature x-ray diffraction analysis to monitor the progress of a displacement reaction involving a reactant gas that was generated and confined within a closed reaction chamber.
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82.40.-g Chemical kinetics and reactions: special regimes and techniques
82.30.Hk Chemical exchanges (substitution, atom transfer, abstraction, disproportionation, and group exchange)
82.20.-w Chemical kinetics and dynamics
82.80.Ej X-ray, Mössbauer, and other γ-ray spectroscopic analysis methods

Debris characteristics of a laser-produced tin plasma for extreme ultraviolet source

Takeshi Higashiguchi, Chirag Rajyaguru, Naoto Dojyo, Yosuke Taniguchi, Koji Sakita, Shoichi Kubodera, and Wataru Sasaki

Rev. Sci. Instrum. 76, 126102 (2005); http://dx.doi.org/10.1063/1.2136874 (3 pages) | Cited 7 times

Online Publication Date: 14 December 2005

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We measured debris characteristics of a tin (Sn) plasma produced by a 10-ns infrared Nd:YAG laser. A maximum kinetic energy of 7 keV of tin ions was observed. Such suprathermal tin ions emitted from a solid planar target consisted of singly and doubly ionized tin ions. Both suprathermal ions and neutral fragments emitted from a target showed the angular distributions of cos4 θ which were narrower than the 13.5-nm extreme ultraviolet (EUV) emission distribution of cos0.5 θ. These measurements would give important information on debris mitigation for efficient EUV sources in the next generation lithography.
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52.70.Nc Particle measurements
52.38.Mf Laser ablation
52.50.Jm Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.)
52.25.Os Emission, absorption, and scattering of electromagnetic radiation

Self-oscillating rubidium magnetometer using nonlinear magneto-optical rotation

P. D. D. Schwindt, L. Hollberg, and J. Kitching

Rev. Sci. Instrum. 76, 126103 (2005); http://dx.doi.org/10.1063/1.2136885 (4 pages) | Cited 20 times

Online Publication Date: 14 December 2005

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The detection of nonlinear magneto-optical rotation (NMOR) of polarized light through alkali atomic vapor is a highly sensitive technique for measuring magnetic fields. We demonstrate that when using frequency modulated light to excite the NMOR resonance, it is possible to cause the system to self-oscillate. The NMOR signal is not a simple replica of the sine wave modulation of the light, but rather contains many higher harmonics of the modulation frequency, and we implement two ways of processing the signal to recover the fundamental modulation frequency in the feedback loop and induce self-oscillation. Self-oscillation simplifies and reduces the power consumption of the electronics required to operate a magnetometer, making the NMOR technique attractive for commercialized magnetic sensors.
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07.55.Ge Magnetometers for magnetic field measurements
85.70.Sq Magnetooptical devices

73-W-long pulse kinetically enhanced copper vapor laser using wide aperture discharge tube

B. Singh, V. V. Subramaniam, S. R. Daultabad, and A. Chakraborty

Rev. Sci. Instrum. 76, 126104 (2005); http://dx.doi.org/10.1063/1.2149003 (3 pages) | Cited 4 times

Online Publication Date: 21 December 2005

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A wide aperture kinetically enhanced copper vapor laser consisting of a ∼ 47 mm bore and 1450 mm length discharge tube is demonstrated with moderate input power of ∼ 5 kW, and overall efficiency of ∼ 1.45%. The laser pulse durations were observed to be ∼ 60 ns full width at half maximum. An increase in output power from 17 to 73 W at ∼ 9.4 kHz (a factor of ∼ 4.3) has been achieved due to kinetic enhancement effects in this laser. Output laser pulse shape monitoring was used for optimization of maximum output power from the laser.
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42.55.Lt Gas lasers including excimer and metal-vapor lasers
42.60.By Design of specific laser systems
42.65.Re Ultrafast processes; optical pulse generation and pulse compression
42.60.Fc Modulation, tuning, and mode locking

On unique parameters and unified formal form of hot-wire anemometric sensor model

P. Ligęza

Rev. Sci. Instrum. 76, 126105 (2005); http://dx.doi.org/10.1063/1.2140491 (3 pages) | Cited 1 time

Online Publication Date: 27 December 2005

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This note reviews the extensively adopted equations used as models of hot-wire anemometric sensors. An unified formal form of the mathematical model of a hot-wire anemometric sensor with otherwise defined parameters is proposed. Those parameters, static and dynamic, have simple physical interpretation and can be easily determined. They show directly the range of sensor application. They determine the metrological properties of the given sensor in the actual medium. Hence, the parameters' values might be ascribed to each sensor in the given medium and be quoted in manufacturers’ catalogues, supplementing the sensor specifications. Because of their simple physical interpretation, those parameters allow the direct comparison of the fundamental metrological properties of various sensors and selection of the optimal sensor for the given research measurement application. The parameters are also useful in modeling complex hot-wire systems.
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06.30.Gv Velocity, acceleration, and rotation
01.30.Rr Surveys and tutorial papers; resource letters
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