Energy Technology Data Exchange (ETDEWEB)

A method for preparing metal for heating by infrared radiance to enable uniform and consistent heating. The surface of one or more metal parts, such as aluminum or aluminum alloy parts, is treated to alter the surface finish to affect the reflectivity of the surface. The surface reflectivity is evaluated, such as by taking measurements at one or more points on the surface, to determine if a desired reflectivity has been achieved. The treating and measuring are performed until the measuring indicates that the desired reflectivity has been achieved. Once the treating has altered the surface finish to achieve the desired reflectivity, the metal part may then be exposed to infrared radiance to heat the metal part to a desired temperature, and that heating will be substantially consistent throughout by virtue of the desired reflectivity.

CERN Document Server

Predictions and measurements of a multimode waveguide interferometer operating in a fibre coupled, ``dual-mode'' regime are reported. With a 1.32 micrometer source, a complete switching cycle of the output beam is produced by a 10.0 nanometer incremental change in the 8.0 micrometer width of the hollow planar mirror waveguide. This equates to a fringe spacing of $\\sim\\lambda /130$. This is an order of magnitude smaller than previously reported results for this form of interferometer.

International Nuclear Information System (INIS)

We report the observation of quantum interference in superfluid 4He. The interferometer, an analog of a dc-superconducting quantum interference device (SQUID), employs a recently reported phenomenon wherein superfluid 4He exhibits Josephson frequency oscillations in an array of submicron apertures. An interference pattern is generated by reorienting the loop of the superfluid 'SQUID' with respect to the Earth's rotation vector, thereby varying the rotation flux in the loop. The experiment is performed at 2 K, a temperature 2000 times higher than previously achieved with superfluid 3He. We find that the interference exists not only when the aperture array current-phase relation is a sinusoidal function characteristic of the Josephson effect, but also at lower temperatures where it is linear and oscillations occur by phase slips. The modest requirements for the interferometer (2 K cryogenics and fabrication of apertures at the level of 100 nm) ...

International Nuclear Information System (INIS)

Current effort of the TAMA project is focused on establishment of the interferometer operation with a new vibration isolation system, called 'Seismic Attenuation System' (SAS). The SAS employs a multiple stage structure to realize soft spring for all of directions, as well as utilizes active control systems to stabilize mechanical resonances in the low frequency region below 1 Hz. The SASs were installed for four test masses, resulting in improvement of cavity length fluctuation below 150 Hz. We describe the structure of the SAS and its local active control system, and the status of the interferometer.

International Nuclear Information System (INIS)

In conducting aircraft surveys for uranium, it is found that temperature inversions can give spurious results because they promote accumulation of radon gas in the atmosphere. The "2"1"4Bi (daughter product of radon) gamma-rays detected from the atmosphere-borne radon are difficult to separate from the "2"1"4Bi gamma-rays originating from the ground, and providing a signature for uranium deposits. The purpose of the present study was to examine the feasibility of making remote temperature soundings of the atmosphere below a low-flying aircraft (140 m or less above ground) by the inversion of radiance measurements taken in the 15-micron carbon dioxide absorption band. Such measurements would identify those temperature inversion conditions possibly leading to an unacceptably large background of gamma-rays from the atmospheric radon. Thus, the incidence of spurious aerial survey data could be greatly reduced. An atmospheric model was set up and the selection of layers ...

Science.gov (United States)

Fabry Perot interferometry is a method of determining instantaneous velocities of an object in motion. The interferometer system is composed of the Fabry Perot interferometer, a laser, an electronic streak camera, and several focusing lenses. The first tests discussed were done on exploding bridgewire devices. During these tests, several system parameters were changed. These changes did not seem to affect the data, which appeared to be consistent. The second tests performed focused on slapper-type devices. It was determined that sandblasted, vapor-deposited aluminum on the slapper material would be required to yield quality data. Streak camera failure prevented much data from being collected. An effort is being made to replace the current streak camera. After it is replaced, a Fabry Perot and velocity interferometry system for any reflector comparison will be made. The results will be published as the conclusion to this report.

CERN Document Server

The concept of the 'white-light cavity' has recently generated considerable research interest in the context of gravitational wave detection. Cavity designs are proposed using negative (or anomalous) dispersion in an intracavity medium to make the cavity resonate over a large range of frequencies and still maintain a high cavity build-up. This paper presents the first experimental attempt and demonstration of white-light effect in a meter long ring cavity using an intracavity atomic medium. The medium's negative dispersion is caused by bi-frequency Raman gain in an atomic vapor cell. Although the white light condition was not perfectly achieved and improvements in experimental control are still desirable, significantly broad cavity response over bandwidth greater than 20 MHz has been observed. These devices will have potential applications in new generation laser interferometer gravitational wave detectors.

CERN Document Server

A possibility of geophysical measurements using the large scale laser interferometrical gravitational wave antenna is discussed. An interferometer with suspended mirrors can be used as a gradiometer measuring variations of an angle between gravity force vectors acting on the spatially separated suspensions. We analyze restrictions imposed by the atmospheric noises on feasibility of such measurements. Two models of the atmosphere are invoked: a quiet atmosphere with a hydrostatic coupling of pressure and density and a dynamic model of moving region of the density anomaly (cyclone). Both models lead to similar conclusions up to numerical factors. Besides the hydrostatic approximation, we use a model of turbulent atmosphere with the pressure fluctuation spectrum f^{-7/3} to explore the Newtonian noise in a higher frequency domain (up to 10 Hz) predicting the gravitational noise background for modern gravitational wave detectors. Our estimates show that this could pose ...

Energy Technology Data Exchange (ETDEWEB)

The effects of fine-particle C, such as diesel soot, on the optical properties of urban haze in the visible wavelength range were explored to determine the dominant effects and to see if simple parameters (such as visual range in green) provide an adequate measure of these effects. It is known that fine-particle C absorbs more strongly in the blue than in the red, so that when it is mixed with a white pigment, the resulting gray can appear somewhat brown. The possibility of a similar effect in urban hazes was investigated, but found not to occur. When the sun is overhead, the near-horizon sky chromaticities caused by mixtures of fine-particle C and non-absorbing aerosol can also be produced by non-absorbing aerosols alone. It is shown that absorbing aerosol will darken the horizon sky, and a simple equation for the radiance of the horizon sky is derived. The effect of absorbing aerosol on the distance at which white and black objects can be seen is calculated.

International Nuclear Information System (INIS)

We discuss the use of active control to reduce mirror position fluctuations at the quantum level. We have shown in a recent experiment that it is possible to reduce the thermal noise of a mirror by measuring and controlling its motion with an optomechanical sensor based on a high-finesse optical cavity. This approach can be extended to lock the mirror motion at the quantum level, and to suppress the quantum effects of radiation pressure in interferometric measurements such as gravitational-wave detectors. The sensitivity improvement is furthermore independent of losses in the interferometer.

Science.gov (United States)

The dynamic behavior of electrooptic bistable devices with delayed feedback is investigated theoretically and experimentally. The operation principle of the system is analyzed by the method of iterated maps. Stable, bistable, periodic, higher periodic, and chaotic solutions are discussed and realized experimentally by using an integrated Mach-Zehnder interferometer on LiNbO3 as a basic nonlinear element. Taking into account the periodic modulator characteristic, the application of this device as a simple and fast bistable and monostable multivibrator is demonstrated. In addition, the synchronization properties of the astable multivibrator are investigated.

Energy Technology Data Exchange (ETDEWEB)

An embodiment of a mercury-free fluorescent lamp combines a low pressure rare gas discharges with a phosphor having a quantum efficiency grater than one. The choice of the rare gas depends on a number of factors, one of which is the resonance transition energy. Less demand is placed the quantum efficiency of the phosphor for a lower energy resonance photon. Xenon has the lowest energy resonance transition of the stable rare gases at 8.5 eV (147 nm) and thus is a good candidate to study. The usefulness of a xenon-based discharge depends on the radiant emittance of the discharge at the resonance wavelength of 147 nm. The radiant emittance from a low pressure xenon positive column discharge is measured using two independent techniques. The first relies on the measurement of the resonance level density using absorption techniques. The effective decay rate of the resonance level is calculated using radiation trapping theory. The product of this density and trapped decay rate yields the ...

CERN Document Server

The DARWIN mission is an Infrared free flying interferometer mission based on the new technique of nulling interferometry. Its main objective is to detect and characterize other Earth-like planets, analyze the composition of their atmospheres and their capability to sustain life, as we know it. DARWIN is currently in definition phase. This PhD work that has been undertaken within the DARWIN team at the European Space Agency (ESA) addresses two crucial aspects of the mission. Firstly, a DARWIN target star list has been established that includes characteristics of the target star sample that will be critical for final mission design, such as, luminosity, distance, spectral classification, stellar variability, multiplicity, location and radius of the star. Constrains were applied as set by planet evolution theory and mission architecture. Secondly, a number of alternative mission architectures have been evaluated on the basis of interferometer ...

Energy Technology Data Exchange (ETDEWEB)

A modulation transfer function (MTF) calibration method based on binary pseudo-random (BPR) gratings and arrays [Proc. SPIE 7077-7 (2007), Opt. Eng. 47, 073602 (2008)] has been proven to be an effective MTF calibration method for a number of interferometric microscopes and a scatterometer [Nucl. Instr. and Meth. A616, 172 (2010)]. Here we report on a further expansion of the application range of the method. We describe the MTF calibration of a 6 inch phase shifting Fizeau interferometer. Beyond providing a direct measurement of the interferometer's MTF, tests with a BPR array surface have revealed an asymmetry in the instrument's data processing algorithm that fundamentally limits its bandwidth. Moreover, the tests have illustrated the effects of the instrument's detrending and filtering procedures on power spectral density measurements. The details of the development of a BPR test sample suitable for calibration of ...

CERN Document Server

We discuss the advantages which the next generation interferometer SKA (the Square Kilometer Array) will bring for Very Long Baseline Interferometry (VLBI) at centimeter wavelengths. With a sensitivity to micro-Jy level flux density, a brightness temperature limit of about 10.000 K, and an expected dynamic range in future VLBI maps of better than 1.000.000, the impact of SKA on the research of compact extragalactic radio sources and their energetic jets will be very strong. We discuss some consequences, including a possible combination of SKA with future space VLBI missions.

Energy Technology Data Exchange (ETDEWEB)

The ongoing upgrade of the Los Alamos Free-Electron Laser (FEL) Facility involves the addition of a photoelectric injector (PEI) and acceleration capability to about 40 MeV. The electron-beam and high-speed diagnostics provide key measurements of charge, beam position and profile, divergence emittance, energy (centroid, spread, slew, and extraction efficiency), micropulse duration, and phase stability. Preliminary results on the facility include optical transition radiation interferometer measurements of divergence (1 to 2 mrad), FEL extraction efficiency (0.6 {plus minus} 0.2%), and drive laser phase stability (< 2 ps (rms)). 10 refs.

International Nuclear Information System (INIS)

An interferometric technique for hard X-rays is presented. It is based on two transmission gratings and a phase-stepping technique, and it provides separate radiographs of the phase and absorption profiles of bulk samples. Tomographic reconstruction yields quantitative three-dimensional maps of the X-ray refractive index and of the attenuation coefficient, with a spatial resolution down to a few microns. The method is mechanically robust, it requires little monochromaticity, and can be scaled up to large fields of view. These are important prerequisites for use with laboratory X-ray sources. Numerous applications ranging from wave front sensing to medical radiography are presently under investigation.

Energy Technology Data Exchange (ETDEWEB)

The potential retinal hazard of dental visible-light photopolymerization units and the efficacy of protective lenses for reducing the potential hazards were assessed. The spectral radiance profiles of 11 visible-light photopolymerization units were measured; and the results were then weighted according to the American Conference of Governmental Industrial Hygienists (ACGIH) Blue Light and Thermal Hazard Functions. The results indicate that there are no thermal hazards to the retina even for the worst case condition. None of the blue-light hazard maximum permissible exposure times is short enough to be of concern unless the individual operator chooses to focus on the light source for an extended period. Those individuals who elect to stare at the light during curing procedures should consider the purchase of protective lenses. The special transmission profiles of 16 protective lenses were measured and new permissible exposure limits calculated for each lens/unit ...

Energy Technology Data Exchange (ETDEWEB)

Concerning the gamma emitters, the only analysis on soils put in evidence the presence of cesium-137 ({sup 137}Cs), that does not come from the cyclotron functioning but from past man action as the Chernobylsk accident and the nuclear weapon tests in atmosphere. Independently of the functioning of the installation, we observe an increase of the ambient gamma radiation only near radioactive waste storage. It results of the storage of the former cyclotron elements. The induced increase is moderated because at 5 meters the values do not exceed the background noise. In relation with the functioning of the installation an increase of the ambient gamma radiation is noticed. Two causes are to considered: the release of radionuclides in atmosphere with gaseous effluents and the radiance of radiation sources inside the building. After the stopping of the installation (48 h at least), no increase of gamma radiation is observed. About the neutrons monitoring, the measures ...

Science.gov (United States)

The in-flight wavelength calibration for the Ozone Monitoring Instrument is discussed. The observed variability in the wavelength scale is two orders of magnitude larger than caused by temperature changes in the instrument. These wavelength variations are the result of rapid changes in time in the radiance levels during an individual observation in the presence of clouds or snow and ice. We have developed a data processing method to account and correct for these changes. In February 2005 this correction was implemented in the official data processing stream. We explain in detail how and how accurately this method works. Before correction, the error in the wavelength scale can be as much as a few tenths of a pixel; after correction it is mostly less than 1/100th of a pixel, which is the required preflight accuracy. This means that higher-level products such as the total column amounts of ozone, NO2, and SO2 are not significantly affected. It is expected that these ...

International Nuclear Information System (INIS)

We present the design of a diagnostic system to measure electron cyclotron absorption at the second harmonic E-mode resonance in the JET pumped divertor plasma. The diagnostic will measure transmission as a function of frequency along one or more sightlines from which the spatial profile of the n_eT_e product will be deduced. The divertor is briefly described, and the electron cyclotron resonance physics relevant to this measurement is reviewed. The problems of measuring transmission using an oversized transmission system are discussed and the chosen measurement technique, a swept frequency interferometer using a coherent radiation source, is described. A prototype of the instrument has been assembled to test the measurement technique. Some data demonstrating the instrument's characteristics are presented. The nonresonant losses, which may affect the interpretation of the measurement, are also discussed. (orig.).

International Nuclear Information System (INIS)

Time-differential magnetic moment measurements on the first-excited Isup(#pi#)=2"+ states in "2"0Ne and "2"4Mg with mean lives of 1.0 and 2.1 ps, respectively are described. The lifetime of the latter state was determined simultaneously. A special detection geometry was designed to improve the experimental #gamma#-ray anisotropy measured with finite-size detectors. For "2"0Ne also a time-integral measurement with charge-state separation was performed. The necessary electronics circuitry built to perform these complicated measurements and the plunger assembly with laser interferometer are also described. A magnetic moment measurement of "2"2Ne(2_1"+) with tau=5.0 ps and transient field measurements at low and high recoil velocities are reported. A discussion of possible extensions of the techniques are given. (Auth.).

International Nuclear Information System (INIS)

The bandwidth of LIGO-like terrestrial interferometric gravitational wave detectors is set by the pole of the Fabry-Perot cavities within the arms of the Michelson interferometer. This constraint arises because the gain of gravitational wave-induced signal sidebands is limited to frequencies within the linewidth of the cavities. The nature of standard Fabry-Perot cavities is such that one cannot independently adjust for increased gain without suffering a loss of bandwidth. If these quantities could be decoupled, the resulting improvement in bandwidth may lead to viable high frequency detectors. A pair of anti-parallel diffraction gratings within a Fabry-Perot cavity can increase the bandwidth of a LIGO-scale detector by a factor of #approx#1000.

CERN Document Server

The detection of a stochastic background of gravitational waves could significantly impact our understanding of the physical processes that shaped the early Universe. The challenge lies in separating the cosmological signal from other stochastic processes such as instrument noise and astrophysical foregrounds. One approach is to build two or more detectors and cross correlate their output, thereby enhancing the common gravitational wave signal relative to the uncorrelated instrument noise. When only one detector is available, as will likely be the case with the Laser Interferometer Space Antenna (LISA), alternative analysis techniques must be developed. Here we show that models of the noise and signal transfer functions can be used to tease apart the gravitational and instrument noise contributions. We discuss the role of gravitational wave insensitive "null channels" formed from particular combinations of the time delay interferometry, and derive a new combination ...

Energy Technology Data Exchange (ETDEWEB)

Measurements are presented of the distribution of average friction factors (f) as well as local and average ({ovr Nu}) heat transfer coefficients for fully developed channel flows with two rib-roughened opposite walls. The temperature measurements were made by using both a laser holographic interferometer and thermocouples. In addition, the reattachment length was determined by flow visualization. The Reynolds number (Re) was varied from 5.0 {times} 10{sup 3} to 5.4 {times} 10{sup 4}; the rib pitch-to-height ratios (Pi/H) were 10, 15, 20; and the rib height-to-hydraulic diameter ratios (H/De) were 0.063, 0.081, and 0.106. The detailed results allowed the peaks of heat transfer augmentation and the regions susceptible to hot spots to be located and allowed the relative contribution of the rib surface and the channel wall to the heat transfer augmentation to be determined. Moreover, relative to a smooth duct, the enhancement of both {ovr Nu} and f at various Re, ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this program was to characterize Time Of Arrival Detectors (TOAD) pins response to shock loading with respect to risetime, amplitude, repeatability and consistency. TOAD pins were subjected to impacts of 35 to 420 kilobars amplitude and approximately 1 ms pulse width to investigate the timing spread of four pins and the voltage output profile of the individual pins. Sets of pins were also aged at 45{degrees}, 60{degrees}, and 80{degrees}C for approximately nine weeks before shock testing at 315 kilobars impact stress. Four sets of pins were heated to 50.2{degrees}C (125{degrees}F) for approximately two hours and then impacted at either 50 or 315 kilobars. Also, four sets of pins were aged at 60{degrees}C for nine weeks and then heated to 50.2{degrees}C before shock testing at 50 and 315 kilobars impact stress, respectively. Particle velocity measurements at the contact point between the stainless steel targets and TOAD pins were made using a Velocity ...

Energy Technology Data Exchange (ETDEWEB)

The consistency of different instruments and methods for measuring two-dimensional (2D) power spectral density (PSD) distributions are investigated. The instruments are an interferometric microscope, an atomic force microscope (AFM) and the X-ray Reflectivity and Scattering experimental facility, all available at Lawrence Berkeley National Laboratory. The measurements were performed with a gold-coated mirror with a highly polished stainless steel substrate. It was shown that these three techniques provide essentially consistent results. For the stainless steel mirror, an envelope over all measured PSD distributions can be described with an inverse power-law PSD function. It is also shown that the measurements can be corrected for the specific spatial frequency dependent systematic errors of the instruments. The AFM and the X-ray scattering measurements were used to determine the modulation transfer function of the interferometric microscope. The corresponding correction procedure is ...

Energy Technology Data Exchange (ETDEWEB)

For InAs-GaAs based quantum dot lasers emitting at 1300 nm, digital modulation showing an open eye pattern up to 12 Gb s{sup -1} at room temperature is demonstrated, at 10 Gb s{sup -1} the bit error rate is below 10{sup -12} at -2 dB m receiver power. Cut-off frequencies up to 20 GHz are realised for lasers emitting at 1.1 {mu}m. Passively mode-locked QD lasers generate optical pulses with repetition frequencies between 5 and 50 GHz, with a minimum Fourier limited pulse length of 3 ps. The uncorrelated jitter is below 1 ps. We use here deeply etched narrow ridge waveguide structures which show excellent performance similar to shallow mesa structures, but a circular far field at a ridge width of 1 {mu}m, improving coupling efficiency into fibres. No beam filamentation of the fundamental mode, low a-factors and strongly reduced sensitivity to optical feedback are observed. QD lasers are thus superior to QW lasers for any system or network. Quantum dot semiconductor optical amplifier (QD ...

International Nuclear Information System (INIS)

A 450 MeV Synchrotron Radiation Source, Indus-1 is being constructed at Centre for Advanced Technology at Indore in central India. This paper narrates our experience in construction and alignment of synchrotron machines which was first of its kind for most of us. Careful design, planning and execution of the work yielded modest results so that alignment accuracies between 0.1 to 0.3 mm could be achieved (in booster synchrotron) and, which have proved to be adequate up till now. The building of the SRS complex was constructed such that machine rings have their foundations isolated from rest of the building. A number of 100 x 150 mm size steel plates were embedded in the concrete of floor and walls to serve as base for reference surveying marks which were established later. The pre-injector and booster ring are enclosed in a radiation shielding zone with separate ventilation system. Dipoles, quadrupoles and a few sextupoles were fiducialised during their field mappings; on a CNC ...