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Construction, testing of the 1 MW, 130-260 GHz Fusion-FEM
Energy Technology Data Exchange (ETDEWEB)
During the previous 9 months the major part of the Fusion-FEM has been constructed. The 2 MV Insulated Core Transformer, the electron gun, the accelerator, the focusing lenses and the undulator have been tested on-site. In the present - temporary - set-up, the electron beam line consists of a 12 A, 80 keV thermionic electron gun, a 2 MeV dc accelerator, beam transport optics, the undulator and a collector. The gun is mounted in the high voltage terminal, which is now at -2 MV, and the undulator and mm-wave system am at ground potential outside the SF{sub 6}-filled pressure tank. This so-called inverse set-up allows easy access to the larger part of the beam line, the undulator and the mm-wave system, which is important in the conditioning phase. The decelerator and depressed collector am not yet installed. The design of the electron beam line has been optimised using the GPS particle-tracking code and the TOSCA code. The TOSCA code is used for accurate field ...
1995-12-31
British Library Electronic Table of Contents (United Kingdom)
Abstract Juvenile cobia (Rachycentron canadum) (100-g) were fed four moist diets (447-476-g-kg-1-dry-wt) where 0, 130, 260 or 390-g-kg-1 of concentrated lizardfish (Saurida undosquamis) silage replaced fresh lizardfish, respectively. Blood and livers were sampled at 0, 6, 12, 24 and 48-h postfeeding at the end of the 3-week experiment. At 6-h postfeeding in all groups, maximum concentrations of most plasma essential amino acids were observed, while significantly lower levels of most non-essential amino acid levels were recorded compared to the other sampled times. At 6 and 12-h after feeding, the concentration of most plasma free amino acid (FAA) increased with an increase in dietary fish silage levels. Most FAA in livers of all groups peaked at 12 and 24-h postfeeding. However, at 48-h po...
2011-01-01
Controlled Bidirectional Quantum Direct Communication by Using a GHZ State
A controlled bidirectional quantum secret direct communication scheme is proposed by using a Greenberger-Horne-Zeilinger (GHZ) state. In the scheme, two users can exchange their secret messages simultaneously with a set of devices under the control of a third party. The security of the scheme is analysed and confirmed.
2006-07-01
The KCAL VERA 22 GHz calibrator survey
We observed at 22 GHz with the VLBI array VERA a sample of 1536 sources with correlated flux densities brighter than 200 mJy at 8 GHz. One half of target sources has been detected. The detection limit was around 200 mJy. We derived the correlated flux densities of 877 detected sources in three ranges of projected baseline lengths. The objective of these observations was to determine the suitability of given sources as phase calibrators for dual-beam and phase-referencing observations at high frequencies. Preliminary results indicate that the number of compact extragalactic sources at 22 GHz brighter than a given correlated flux density level is twice less than at 8 GHz.
2011-01-01
Energy Technology Data Exchange (ETDEWEB)
Eight cross spiders (Araneus diadematus) were exposed overnight (16 h) during web-building activity to pulsed 9.6-GHz microwaves at average power densities of 10, 1, and 0.1 mW/sq. cm. (estimated SARs 40, 4, and 0.4 mW/g). Under these conditions, 9.6-GHz pulsed microwaves did not affect the web-spinning ability of the cross spider.
1986-01-01
A preliminary design for a one GHz NMR spectrometer magnet
International Nuclear Information System (INIS)
The authors have performed a preliminary design for a persistent GHz NMR magnet at 23.5 T and 1.8 K operating conditions. In this paper the authors shall address the issues of realistic conductor selection, the coil design, the magnetic and mechanical analysis of the coil, and the required field uniformity. In addition, they shall describe the GHz magnet cryostat with a practical 1.8 K J-T refrigerator system. Finally vibration isolation system and field shield design and its associated field harmonics will be analyzed.
1993-09-20
Low-noise Josephson mixers at 115 GHz using recyclable point contacts
International Nuclear Information System (INIS)
Thermally recyclable Nb point-contact Josephson junctions are investigated as low-noise mixers with an external local oscillator at 115 GHz. The best single sideband mixer noise temperature achieved is 140 ( +- 20) K with a (SSB) conversion loss of 2.4 ( +- 0.5) dB. Such rugged junctions are suitable for use in practical receivers and should give unprecedented sensitivity at the shorter millimeter wavelengths.
Josephson junctions as heterodyne detectors
International Nuclear Information System (INIS)
Heterodyne detection with a point-contact Josephson junction has been investigated both experimentally and theoretically. The measured performance of the device at 36 GHz is in good agreement with the theory. By operating vanadium point contacts at 1.4 K, the authors have achieved a single-sideband (SSB) mixer noise temperature of 54 K with a conversion gain of 1.35 and a signal bandwidth on the order of 1 GHz. A potentially impressive performance for these devices at submillimeter wavelengths can be extrapolated from the results.
Design and fabrication of a traveling-wave muffin-tin accelerating structure at 90 GHz
Energy Technology Data Exchange (ETDEWEB)
A prototype of a muffin-tin accelerating structure operating at 32 times the SLAC frequency (2.856 GHz) was built for research in high gradient acceleration. A traveling-wave design with single input and output feeds was chosen for the prototype which was fabricated by wire electrodischarge machining. Features of the mechanical design for the prototype are described. Design improvements are presented including considerations of cooling and vacuum.
1997-05-01
17- and 24-GHz observations of southern pulsars
We present observations of PSRs J0437-4715, J0738-4042, J0835-4510, J0908-4913, J1048-5832, J1622-4950, J1644-4559, J1721-3532 and J1740-3015 at 17 GHz using the Parkes radio telescope. All nine were detected at 17 GHz, additionally, we detected PSR J0835-4510 and J1622-4950 at 24 GHz. Polarization profiles of each pulsar and the variation with frequency are discussed. In general, we find that the highly polarized edge components of young pulsars continue to dominate their profiles at 17 GHz. Older pulsars (?105 yr) appear to be almost completely depolarized. Our detection of PSR J0437-4715 is the highest frequency observation of a millisecond pulsar to date, and implies a luminosity at 17 GHz of 14 ?Jy kpc2, and a mean spectral index of 2.2. We find that the spectral index of the magnetar PSR J1622-4950 is flat between 1.4 and 24 GHz, similar to the other ...
2011-06-01
Energy Technology Data Exchange (ETDEWEB)
The LS electromagnetic band (1-4 GHz) is widely used both in domestic and industrial domains. Several studies suggested that the biological systems would exhibit a specific sensitivity to the 2.45 GHz microwaves (water resonance frequency). Potential human health hazards and especially a disruption of the cholinergic system have been reported, due to exposure to microwaves even at low power density. This work presents a multi-parametric study of freely moving rat where neuro-physiology was investigated during 70 hours using neurochemical (micro-dialysis technique), electrophysiological, behavioral (vigilance stages quantification) and thermo-physiological approaches. The rats were exposed 24 hours to a 2.45 GHz pulsed electromagnetic field at low power density. In this exposure conditions, no significant effect have been reported. (authors)
2007-06-15
High power testing of a 17 GHz photocathode RF gun
Energy Technology Data Exchange (ETDEWEB)
The authors report experimental results on a high gradient 17 GHz RF photocathode gun. The photocathode RF gun is a novel electron beam source intended to meet the requirements set by future high-energy linear colliders and next generation free electron lasers. A coupled pair of pillbox TM{sub 010}-like resonators is excited by sidewall coupled microwaves at 17 GHz. A picosecond ultraviolet laser pulse illuminates one wall of the structure at the axis of symmetry. Electrons are released by the photoelectric effect and are accelerated by the electric field of the microwaves in the cavity. The high frequency of operation raises the RF breakdown limit allowing strong electric fields to be used. In turn, the intense fields result in rapid acceleration of the electrons to relativistic speeds and reduced space charge induced emittance growth.
1996-12-31
Energy Technology Data Exchange (ETDEWEB)
Anesthetized rats were exposed to 5.6-GHz continuous-wave radiofrequency radiation (RFR) at an average power density of 60 mW/Sq. cm (average specific absorption rate 12 W/kg). Exposure was performed to raise colonic temperature from 38.5 to 39.5C. Following acute administration of chlorpromazine, body temperature exhibited a faster return to baseline temperature when exposure was discontinued. When exposure was initiated at 38.5C and continued until lethal temperature resulted, chlorpromazine-treated animals exhibited significantly shorter survival times than saline-treated animals. Thus, although chlorpromazine enhanced thermoregulatory efficiency at colonic temperature below 39.5 deg C, the drug caused increased susceptibility to terminal RFR. The present results, when compared with previous studies of irradiation at 2.8 GHz, indicate that the effects of chlorpromazine on thermal response to RFR during intermittent and terminal exposure are ...
1988-01-01
Propagation data at 20/40 GHz and the propagation needs of Milstar
There are a number of propagation issues that need further investigation for efficient system planning for EHF communication systems. Especially needed are better cloud and rain characterizations. A method for estimating one of the rain induced effects of interest, outage duration, is presented.
1994-08-01
Energy Technology Data Exchange (ETDEWEB)
The authors report a two-temperature RF bias stress test on nominal 1.2 W 7.5 GHz GaAs/AlGaAs HBT unit cell amplifiers. MTTF`s of 2020 and 1340 hours were obtained at Tj = 218{degrees}C and 245{degrees}C, respectively, under nominal input bias. An activation energy of 0.42 eV is estimated, consistent with published results for similar devices under DC bias stress.
1995-12-31
Josephson effect mm-wave receivers
International Nuclear Information System (INIS)
Josephson effect heterodyne mixers with external local oscillators are very promising low noise mm-wave receivers for applications such as radio astronomy. Experiments at 36 GHz have shown that both the noise and the conversion efficiency of mixers made using Nb point contacts are in quantitative agreement with values calculated from the resistively shunted junction (RSJ) model. Preliminary measurements at 140 GHz suggest that this agreement extends to higher frequencies. In this paper the theoretical limits to the sensitivity of such receivers are explored as a function of the signal frequency. (Auth.).
5 GHz 200 Mbit/s radio over polymer fibre link with envelope detection at 650 nm wavelength
DEFF Research Database (Denmark)
All-optical envelope detection of a 5 GHz 200 Mbit/s modulated radio frequency signal is achieved using a 650 nm resonant cavity light emitting diode. Error-free transmission is achieved over a 50 m-long link of 1 mm diameter graded index polymer optical fibre (POF). The presented system has potential applications in low cost and low complexity short range wireless and wireline POF-based transmission links.
2008-01-01
Satellite CMB anisotropy missions and new generation of balloon-borne and ground experiments, make use of complex multi-frequency instruments at the focus of a meter class telescope. Between 70 GHz and 300 GHz, where foreground contamination is minimum, it is extremely important to reach the best trade-off between the improvement of the angular resolution and the minimization of the straylight contamination mainly due to the Galactic emission. We focus here, as a working case, on the 30 and 100 GHz channels of the Planck Low Frequency Instrument (LFI). We evaluate the GSC introduced by the most relevant Galactic foreground components for a reference set of optical configurations. We show that it is possible to improve the angular resolution of 5-7% by keeping the overall GSC below the level of few microKelvin. A comparison between the level of straylight introduced by the different Galactic components for different beam ...
2003-01-01
We review results from general relativistic axisymmetric magnetohydrodynamic simulations of accretion in Sgr A*. We use general relativistic radiative transfer methods and to produce a broad band (from millimeter to gamma-rays) spectrum. Using a ray tracing scheme we also model images of Sgr A* and compare the size of image to the VLBI observations at 230 GHz. We perform a parameter survey and study radiative properties of the flow models for various black hole spins, ion to electron temperature ratios, and inclinations. We scale our models to reconstruct the flux and the spectral slope around 230 GHz. The combination of Monte Carlo spectral energy distribution calculations and 230 GHz image modeling constrains the parameter space of the numerical models. Our models suggest rather high black hole spin ($a_*\\approx 0.9$), electron temperatures close to the ion temperature ($T_i/T_e \\sim 3$) and high inclination angles ($i ...
2010-01-01
High frequency VLBI observations of the scatter broadened quasar B2005+403
The quasar B2005+403 located behind the Cygnus region, is a suitable object for studying the interplay between propagation effects, which are extrinsic to the source and source intrinsic variability. On the basis of VLBI experiments performed at 1.6, 5, 8, 15, 22, and 43GHz between 1992-2003 and parallel multi-frequency monitoring of the total flux density, we investigated the variability of total flux density and source structure. Below 8 GHz, the point-like VLBI source is affected by scatter-broadening of the turbulent interstellar medium, which is located along the line of sight and likely associated with the Cygnus region. We present and discuss the measured frequency dependence of the source size, which shows a power-law with slope of -1.91+/-0.05. From the measured scattering angle at 1GHz of 77.1+/-4.0mas a SM=0.43+/-0.04 m^{-20/3} kpc is derived, consistent with the general properties of the ISM in this direction. ...
2006-01-01
Energy Technology Data Exchange (ETDEWEB)
The peak flux relationship between hard X-rays and microwaves from solar flares is studied using about 400 events simultaneously recorded with the hard X-ray burst spectrometer on the SMM satellite and the Nobeyama 17 GHz radiometer. The data indicate that the hard X-ray and microwave peak fluxes correlate best for X-ray energies of less than about 80 keV for impulsive flares and greater than about 360 keV for extended flares. By postulating that electrons responsible for microwave emission at 17 GHz are those emitting hard X-rays at these photon energies, it is concluded that: (1) in impulsive flares, microwaves at about 20 GHz are emitted mainly by electrons of less than about 200 keV from a layer through which the electrons stream down into the thick-target hard X-ray source; and (2) in extended flares, microwaves are emitted mainly by MeV electrons trapped in a coronal loop or loops. 59 references.
1988-01-01
Deterministic secure direct communication using GHZ states and swapping quantum entanglement
International Nuclear Information System (INIS)
We present a deterministic secure direct communication scheme via entanglement swapping, where a set of ordered maximally entangled three-particle states (GHZ states), initially shared by three spatially separated parties, Alice, Bob and Charlie, functions as a quantum information channel. After ensuring the safety of the quantum channel, Alice and Bob apply a series of local operations on their respective particles according to the tripartite stipulation and the secret message they both want to send to Charlie. By three of Alice, Bob and Charlie's Bell measurement results, Charlie is able to infer the secret messages directly. The secret messages are faithfully transmitted from Alice and Bob to Charlie via initially shared pairs of GHZ states without revealing any information to a potential eavesdropper. Since there is no transmission of the qubits carrying the secret message between any two of them in the public channel, it is completely ...
2005-06-24
British Library Electronic Table of Contents (United Kingdom)
This paper presents experimental investigations of the all-optical synchronization of a distributed Bragg reflector (DBR) laser self-pulsating at 40GHz on various injected bit-rate signals. Even though there is no modulation applied to this laser, it exhibits a modulation of its output emission, measured at 39.7GHz with a linewidth of 30MHz. Such performance is exploited in all-optical clock recovery for a return-to-zero data stream at 40Gbit/s. The SP-DBR laser wavelength and the injected signal wavelength are 10nm apart. All-optical synchronization is demonstrated at 40Gbit/s with a linewidth of less than 20MHz for injected signals at 10 and 20Gbit/s, respectively. Thus the SP-DBR laser proves to be very versatile and can be synchronized on various bit-rate data signals.
2009-01-01
International Nuclear Information System (INIS)
Power extraction using a dielectric-loaded (DL) waveguide is a way to generate high-power radio frequency (RF) waves for future particle accelerators, especially for two-beam-acceleration. In a two-beam-acceleration scheme, a low-energy, high-current particle beam is passed through a deceleration section of waveguide (decelerator), where the power from the beam is partially transferred to trailing electromagnetic waves (wakefields); then with a properly designed RF output coupler, the power generated in the decelerator is extracted to an output waveguide, where finally the power can be transmitted and used to accelerate another usually high-energy low-current beam. The decelerator, together with the RF output coupler, is called a power extractor. At Argonne Wakefield Accelerator (AWA), we designed a 7.8GHz power extractor with a circular DL waveguide and tested it with single electron bunches and bunch trains. The output RF frequency (7.8GHz) ...
The Planck-ATCA Coeval Observations project: the faint sample
British Library Electronic Table of Contents (United Kingdom)
Abstract The Planck-ATCA Coeval Observations (PACO) project collected data between 4.5 and 40 GHz for 482 sources selected within the Australia Telescope 20 GHz (AT20G) catalogue and observed with the Australia Telescope Compact Array. Observations were done almost simultaneously with the-Planck-satellite, in the period between 2009 July and 2010 August. In this paper, we present and discuss the data for the complete sample of 159 sources with-SAT20G > 200-mJy in the South Ecliptic Pole region. The Planck Early Release Compact Source Catalogue (ERCSC) contains 57 of our sources. A comparison between the PACO catalogue and the ERCSC confirms that the reliability of the latter is better than 95-per cent. The missing ERCSC sources are typically associated with the Large Magellanic Cloud, the ...
2011-01-01
British Library Electronic Table of Contents (United Kingdom)
A novel method of simultaneous realization of optical carrier-suppression and single-sideband modulation using fiber Fabry-Perot tunable filter is presented. In order to enhance transmission performance of radio over fiber links, we use a fiber Fabry-Perot tunable filter to filter out one sideband as well as suppress the optical carrier power. The results demonstrate 20.5dB and 14.2dB improvement in the signal noise ratios when 18GHz and 10GHz microwave signals carrying 5Mbit/s quadrature-phase-shift-keyed (QPSK) format data is transmitted over 35 km single mode fiber, respectively.
2006-01-01
Submegahertz linewidth at 240 GHz from an injection-locked free-electron laser
International Nuclear Information System (INIS)
Radiation from an ultrastable 240 GHz solid state source has been injected, through an isolator, into the cavity of the University of California, Santa Barbara millimeter-wave free-electron laser (FEL). High-power FEL emission, normally distributed among many of the cavity's longitudinal modes, is concentrated into the single mode to which the solid state source has been tuned. The linewidth of the FEL emission is 0.5 MHz, consistent with the Fourier transform limit for the 2 #mu#s pulses. This demonstration of frequency-stable, ultranarrow-band FEL emission is a critical milestone on the road to FEL-based pulsed electron paramagnetic resonance spectroscopy.
2007-10-22
High power testing of a 17 GHz photocathode RF gun
Energy Technology Data Exchange (ETDEWEB)
The physics and technological issues involved in high gradient particle acceleration at high microwave (RF) frequencies are under study at MIT. The 17 GHz photocathode RF gun has a 1 1/2 cell ({pi} mode) room temperature cooper cavity. High power tests have been conducted at 5-10 MW levels with 100 ns pulses. A maximum surface electric field of 250 MV/m was achieved. This corresponds to an average on-axis gradient of 150 MeV/m. The gradient was also verified by a preliminary electron beam energy measurement. Even high gradients are expected in our next cavity design.
1995-12-31
Chinese research on high-power microwaves. Studies in Chinese Science
Energy Technology Data Exchange (ETDEWEB)
The study examines advances in Chinese High Power Microwaves (HPM) research and its associated technologies: pulsed power, high-power microwave sources, and high-power microwave components. It draws from open literature published in Chinese and English, communication with US scholars who have visited China recently, and communication with Chinese researchers in the United States. The study is limited to frequencies ranging from 1 GHz to 300 GHz. It includes both high peak power microwaves and high average power microwaves. The technical review section of this study is ordered in technological sequence, starting with the pulsed-power systems required to form the intense relativistic electron beams, then assessing microwave source research and development, and finally discussing high-power microwave components.
1990-05-01
5 GHz GaAs monolithic astable multivibrator type voltage controlled oscillator
A 5 GHz GaAs monolithic astable multivibrator-type voltage-controlled oscillator has been developed. The monolithic oscillator uses 2 micron long self-aligned TiW-silicide gate MESFETs as well as GaAs Schottky diodes for capacitance. Good agreement between the experiment and calculations for oscillation frequency characteristics versus control voltage is obtained by assuming donor density in the FET active layer to be a Gaussian distribution. This oscillator is useful for monolithic front ends and phase-locked oscillators used in microwave signal processing. X-band oscillation frequency can be obtained with 1 micron long gate FET and low loss resonance inductors.
1984-03-01
Niobium superconducting cavity
This 5-cell superconducting cavity, made from bulk-Nb, stems from the period of general studies, not all directed towards direct use at LEP. This one is dimensioned for 1.5 GHz, the frequency used at CEBAF and also studied at Saclay (LEP RF was 352.2 MHz). See also 7908227, 8007354, 8209255, 8210054, 8312339.
1980-01-01
Experimental realization of Dicke states of up to six qubits for multiparty quantum networking
We report the first experimental generation and characterization of a six-photon Dicke state and demonstrate its remarkable versatility by projecting out four- and five-photon Dicke states, in addition to four-photon GHZ- and W-states. These multipartite states are studied by developing experimentally favorable characterization tools. Furthermore, we show that Dicke states have interesting applications in multiparty quantum networking protocols such as open-destination teleportation, telecloning and quantum secret sharing.
2009-01-01
Evolution of longitudinal modes in low voltage FEL
Energy Technology Data Exchange (ETDEWEB)
A low voltage FEL operating at 130 kV which can be run cw with a continuous electron beam current level up to 12 mA has been constructed for the X-Band microwave range (8-12 GHz). In this poster, we will report on the dependence on time, after the electron beam is switched on, of the growth and competition of those longitudinal modes in the cavity having nett gain.
1995-12-31
Application of coherent lidar to ion measurements in plasma diagnostics
Energy Technology Data Exchange (ETDEWEB)
A coherent lidar system has been constructed for the measurement of alpha particles in a burning plasma. The lidar system consists of a pulsed CO{sub 2} laser transmitter and a heterodyne receiver. The receiver local oscillator is a cw, sequence-band CO{sub 2} laser operating with a 63.23 GHz offset from the transmitter.
1997-03-01
Simulations of the Microwave Sky
Energy Technology Data Exchange (ETDEWEB)
We create realistic, full-sky, half-arcminute resolution simulations of the microwave sky matched to the most recent astrophysical observations. The primary purpose of these simulations is to test the data reduction pipeline for the Atacama Cosmology Telescope (ACT) experiment; however, we have widened the frequency coverage beyond the ACT bands and utilized the easily accessible HEALPix map format to make these simulations applicable to other current and near future microwave background experiments. Some of the novel features of these simulations are that the radio and infrared galaxy populations are correlated with the galaxy cluster and group populations, the primordial microwave background is lensed by the dark matter structure in the simulation via a ray-tracing code, the contribution to the thermal and kinetic Sunyaev-Zel'dovich (SZ) signals from galaxy clusters, groups, and the intergalactic medium has been included, and the gas prescription to model the SZ signals has ...
2009-12-16
Transformation of the ATOMKI-ECRIS into a Plasma Device
International Nuclear Information System (INIS)
Complete text of publication follows. In order to extend the capabilities of the electron cyclotron resonance (ECR) ion source (ECRIS) of ATOMKI it has been transformed into a special plasma facility [1,2]. The transformation is reversible and was simply done by changing several main components of the ion source by new ones, namely: the hexapole magnet, the plasma chamber and the microwave source. The basic requirements of the transformation were: (1) most parts of the present ECRIS should be used in the new assembly in the same way and (2) the transformation time between the two operation modes should not be more than 2-3 days (in both directions). The following sub-systems are used identically in both configurations: solenoid coils, vacuum system, gas dosing system, ovens, probes. The extraction optics and beam transport system can also be used in the new configuration to check the components and charge-state of the plasma. A new, large, but unusually thin cylindrical NdFeB hexapole ...
2006-01-01
TTF HOM Data Analysis with Curve Fitting Method
Energy Technology Data Exchange (ETDEWEB)
To investigate the possibility of using HOM signals induced in SC cavities as beam and cavity diagnostics, narrow band (20 MHz) data was recorded around the strong TE111-6(6{pi}/9-like) dipole modes (1.7 GHz) in the 40 L-band (1.3 GHz) cavities at the DESY TTF facility. The analyses of these data have so far focused on using a Singular Value Decomposition (SVD) technique to correlate the signals with each other and data from conventional BPMs to show the dipole signals provide an alternate means of measuring the beam trajectory. However, these analyses do not extract the modal information (i.e., frequencies and Q's of the nearly degenerate horizontal and vertical modes). In this paper, we described a method to fit the signal frequency spectrum to obtain this information, and then use the resulting mode amplitudes and phases together with conventional BPM data to determine the mode polarizations and relative centers and tilts. Compared ...
2009-07-14
NATIONAL HIGH MAGENTIC FIELD LABORATORY FEL INJECTOR DESIGN CONSIDERATION
Energy Technology Data Exchange (ETDEWEB)
A Numerical study of beam dynamics was performed for two injector systems for the proposed National High Magnetic Field Laboratory at the Florida State University (FSU) Free Electron Laser (FEL) facility. The first considered a system consisting of a thermionic DC gun, two buncher cavities operated at 260 MHz and 1.3 GHz and two TESLA type cavities, and is very similar to the injector of the ELBE Radiation Source. The second system we studied uses a DC photogun (a copy of JLab FEL electron gun), one buncher cavity operated at 1.3 GHz and two TESLA type cavities. The study is based on PARMELA simulations and takes into account operational experience of both the JLab FEL and the Radiation Source ELBE. The simulations predict the second system will have a much smaller longitudinal emittance. For this reason the DC photo gun based injector is preferred for the proposed FSU FEL facility.
2007-06-25
International Nuclear Information System (INIS)
Ordered mesoporous C-TiO2 nanocomposites with crystalline framework were prepared by the evaporation-induced triconstituent co-assembly method. The products were characterized by XRD, TEM, N2 adsorption-desorption and TG. Their microwave absorption properties were investigated by mixing the product and epoxy resin. It is found that the peak with minimum reflection loss value moves to lower frequencies and the ordered mesoporous C-TiO2 nanocomposite possesses an excellent microwave absorbing property with the maximum reflection loss of -25.4 dB and the bandwidth lower than -10 dB is 6.6 GHz. The attenuation of microwave can be attributed to dielectric loss and their absorption mechanism is discussed in detail. The mesoporous C-TiO2 nanocomposites also exhibit a lower infrared emissivity in the wavelength from 8 to 14 ?m than that of TiO2-free powder. -- Graphical abstract: Ordered mesoporous C-TiO2 nanocomposite with crystalline framework possess excellent microwave ...
2010-12-01
Extended radio emission in MOJAVE Blazars: Challenges to Unification
We present the results of a study on the 1.4 GHz kpc-scale radio emission in the complete flux density limited MOJAVE sample, comprising 135 radio-loud AGNs. While extended emission is detected in the majority of the sources, about 7% of the sources exhibit only radio core emission. Many BL Lacs exhibit extended radio power and kpc-scale morphology typical of powerful FRII jets, while a substantial number of quasars possess radio powers intermediate between FRIs and FRIIs. This poses challenges to the simple radio-loud unified scheme, which links BL Lacs to FRIs and quasars to FRIIs. We find a significant correlation between extended radio emission and pc-scale jet speeds: the more radio powerful sources possess faster jets. This indicates that the 1.4 GHz (or low frequency) radio emission is indeed related to jet kinetic power. Various properties such as extended radio power and apparent pc-scale jet speeds vary smoothly between different ...
2010-01-01
Demonstration and Optimization of a Drive Laser for an X-Band Photoinjector
Energy Technology Data Exchange (ETDEWEB)
Recently, a drive laser for an S-band (2.86 GHz) rf photoinjector, designed to provide a pulse that has a flat temporal and spatial profile, has been built, commissioned, and put into service as part of the LLNL Compton-scattering monoenergetic {gamma}-ray source program. This laser is based on an all-fiber oscillator and front-end amplification system, and provides both the laser light to generate the electrons as well as the rf signal that is amplified to accelerate them. Now, a new 11.424 GHz photoinjector is being developed, which has required a revised design for the laser system. The higher frequency has placed more stringent requirements on the synchronization stability, delivered pulse length, and pulse rise times to maintain the desired emittance. Presented here are the overall design and measured performance of the current system and a discussion of what changes are being made to address observed shortcomings and more demanding ...
2009-04-17
CLUSTER: a high frequency H-mode coupled cavity linac for low and medium energies
We propose an innovative linear accelerating structure, particularly suited for hadrontherapy applications. Its two main features are compactness and good power efficiency at low beam velocities: the first is achieved through a high working frequency and a consequent high accelerating gradient, the second is obtained by coupling several H-mode cavities together. The structure is called CLUSTER, which stands for "Coupled-cavity Linac USing Transverse Electric Radial field". In order to compare the performance of this structure with other hadrontherapy linac designs involving high frequencies, a conceptual study has been performed for an operating frequency of 3 GHz. Moreover a proof of principle has been obtained through RF measurements on a prototype operating at 1 GHz. An accelerator complex using a CLUSTER linac is also considered for protontherapy purposes. The whole complex is called cyclinac and is composed of a commercial cyclotron ...
2006-01-01
We propose a simultaneous quantum secure direct communication scheme between one party and other three parties via four-particle GHZ states and swapping quantum entanglement. In the scheme, three spatially separated senders, Alice, Bob and Charlie, transmit their secret messages to a remote receiver Diana by performing a series of local operations on their respective particles according to the quadripartite stipulation. From Alice, Bob, Charlie and Diana's Bell measurement results, Diana can infer the secret messages. If a perfect quantum channel is used, the secret messages are faithfully transmitted from Alice, Bob and Charlie to Diana via initially shared pairs of four-particle GHZ states without revealing any information to a potential eavesdropper. As there is no transmission of the qubits carrying the secret message in the public channel, it is completely secure for the direct secret communication. This scheme can be considered as a ...
2005-10-01
A Distinctive Disk-Jet Coupling in the Seyfert-1 AGN NGC 4051
We report on the results of a simultaneous monitoring campaign employing eight Chandra X-ray (0.5-10 keV) and six VLA/EVLA (8.4 GHz) radio observations of NGC 4051 over seven months. Evidence for compact jets is observed in the 8.4 GHz radio band; This builds on mounting evidence that jet production may be prevalent even in radio-quiet Seyferts. Assuming comparatively negligible local diffuse emission in the nucleus, the results also demonstrate an inverse correlation of L_radio proportional to L_X-ray ^(-0.72+/-0.04) . Current research linking the mass of supermassive black holes and stellar-mass black holes in the "low/hard" state to X-ray luminosities and radio luminosities suggest a "fundamental plane of accretion onto black holes" that has a positive correlation of L_radio proportional to L_X-ray^(0.67+/-0.12) . Our simultaneous results differ from this relation by more than 11 sigma, indicating that a separate mode of accretion and ...
2010-01-01
Thermonuclear reactivity of D-T fusion plasma with spin-polarized fuel
Energy Technology Data Exchange (ETDEWEB)
The thermonuclear reactivity of deuterium(D) - tritium(T) fusion plasma with spin-polarized fuel has been studied. Two mechanisms of depolarization, collisions and waves, in the high temperature fusion plasma have been considered. The binary collisions have been found not to change the nuclear spin states. The waves with a frequency of a few GHz, however, changes the spin states appreciably, when {delta}B/B{sub 0} (the ratio of the amplitude of the fluctuating magnetic field to the external field) becomes larger than 10{sup -5}. (author)
1999-04-01
International Nuclear Information System (INIS)
We studied the niobium re-entrant cavity utilized by the Australian group in the Niobe gravitational wave detector. Instead of using their non-contact re-entrant cavity, we plan to change it to a closed one to be used in the parametric transducers of the Brazilian Mario Schenberg detector. The performance of the transducer depends on some cavity parameters such as the electrical Q and the electrical coupling. We measured the resonant frequency and the loaded electrical Q as a function of the probe position in a closed niobium #approx#15 GHz cavity operating at 4.2 K.
2004-03-07
Progress and Plans for R&D and the Conceptual Design of the ILC Main Linacs
The International Linear Collider Main Linacs are based on superconducting accelerator structures operating at 1.3 GHz. The basis for this design has been developed and tested at DESY and R&D is progressing at many laboratories around the world including DESY, Orsay, KEK, FNAL, SLAC, Cornell, and JLAB. The status of the TESLA-style cavities and rf system will be reviewed and parameters for the ILC linac will be described. The role of the different linac test facilities will discussed and the critical items and R&D program to support a Conceptual Design and Technical Design will be outlined.
2005-01-01
Operational status of the Brookhaven National Laboratory Accelerator Test Facility
International Nuclear Information System (INIS)
Initial design parameters and early operational results of a 50 MeV high brightness electron linear accelerator are described. The system utilizes a radio frequency electron gun operating at a frequency of 2.856 GHz and a nominal output energy of 4.5 MeV followed by two, 2#pi#/3 mode, disc loaded, traveling wave accelerating sections. The gun cathode is photo excited with short (6 psec) laser pulses giving design peak currents of a few hundred amperes. The system will be utilized to carry out infra-red FEL studies and investigation of new high gradient accelerating structures.
1990-06-11
Method of the cementing of material
Energy Technology Data Exchange (ETDEWEB)
Invention relates to woodworking industry and concerns method of cementing of materials of foam plastic with duralumin, glued plywood, etc. Known methods of cementing of materials by effect of electromagnetic field of superhigh frequencies are unproductive and do not make it possible to cement parts on the plane. Target of invention - acceleration of process of cementing of planar, including of complex configuration, parts and assemblies from wood, foam plastic, duralumin, glued plywood and other materials. For this material is cemented under the effect of directed electromagnetic field of superhigh frequency in the range 01-50 GHz, the specific power of 0.5-15 W/cm3.
1990-10-30
Inverse free electron laser beat-wave accelerator research
International Nuclear Information System (INIS)
A calculation on the stabilization of the sideband instability in the free electron laser (FEL) and inverse FEL (IFEL) was completed. The issue arises in connection with the use of a tapered (''variable-parameter'') undulator of extended length, such as might be used in an ''enhanced efficiency'' traveling-wave FEL or an IFEL accelerator. In addition, the FEL facility at Columbia was configured as a traveling wave amplifier for a 10-kW signal from a 24-GHz magnetron. The space charge field in the bunches of the FEL was measured. Completed work has been published.
Determining top dead center in fired internal combustion engines by microwaves
Energy Technology Data Exchange (ETDEWEB)
For the determination of top dead center (TDC) of a running engine a measuring system using microwaves was developed by AEG and Volkswagen AG. The measuring method utilizes the Doppler shift of the microwaves, which were reflected at the up and down moving piston, and the varying resonance properties of the combustion chamber. The system works with a frequency of 61.4 GHz and can be used as well for spark ignition as form compression ignition engines, particularly for direct injection engines. The output signal is symmetrical to TDC. For data acquisition and data processing, i.e. the calculation of the point of symmetry, the computer system FARES is used in a special assembly.
1986-01-01
We report on the design, fabrication and testing of two superconducting passive microwave components, a quadrature hybrid and a 20 dB directional coupler. These components are designed to be integrated with superconducting qubits or Josephson parametric amplifiers and used in quantum information processing applications. For the coupler, we measure return loss and isolation > 20 dB, and insertion loss 20 dB and insertion loss < 0.3 dB in a 10% band around 6.5 GHz. These values are within the design specifications of our application; however, we find a 7% difference between the designed and measured center frequency for the hybrid.
2010-01-01
We analyse the capacity of a simultaneous quantum secure direct communication scheme between the central party and other M parties via M+1-particle GHZ states and swapping quantum entanglement. It is shown that the encoding scheme should be secret if other M parties wants to transmit M+1 bit classical messages to the centre party secretly. However, when the encoding scheme is announced publicly, we prove that the capacity of the scheme in transmitting the secret messages is 2 bits, no matter how large M is.
2006-10-01
British Library Electronic Table of Contents (United Kingdom)
We have measured the frequency-dependent dielectric function of semi-crystalline polybutylene terephthalate (PBT) in the terahertz region between 100?GHz and approximately 2.8?THz. A characteristic band is observed around 2.38?THz. The intensity of this band is a good indicator of the degree of crystallinity of the different samples. A potential assignment of this band is proposed, based on the comparison with spectroscopic data of the structurally very similar polyethylene terephtalate (PET). Furthermore, the frequency-dependent index of refraction of PBT reveals more insight about the morphology and different thermal history of the samples under investigation.
2011-01-01
Analysis of the beam bunching produced by a free electron laser
International Nuclear Information System (INIS)
A high-power microwave Free Electron Laser (FEL) experiment has been performed to study the inherent electron beam bunching that occurs in the FEL interaction. An induction linac delivered a 1 kA, 2.2 MeV electron beam to a FEL amplifier. In the process of amplifying the input signal of frequency 35 GHz to power levels of the order of 10 MW, the electron beam was bunched by the ponderomotive force. In this paper we describe the FEL experiment and the optical technique that was used to observe the bunches. Their properties as functions of the basic FEL parameters are discussed. copyright 1996 American Institute of Physics.
Energy Technology Data Exchange (ETDEWEB)
The MTX explored the plasma heating effects of 140 GHz microwaves from both Gyrotrons and from the IMP FEL wiggler. The Gyrotron was long pulse length (0.5 seconds maximum) and the FEL produced short-pulse length, high-peak power, single and burst modes of 140 GHZ microwaves. Full-power operations of the IMP FEL wiggler were commenced in April of 1992 and continued into October of 1992. The Experimental Test Accelerator H (ETA-II) provided a 50-nanosecond, 6-MeV, 2--3 kAmp electron beam that was introduced co-linear into the IMP FEL with a 140 GHz Gyrotron master oscillator (MO). The FEL was able to amplify the MO signal from approximately 7 kW to peaks consistently in the range of 1--2 GW. This microwave pulse was transmitted into the MTX and allowed the exploration of the linear and non-linear effects of short pulse, intense power in the MTX plasma. Single pulses were used to explore and gain operating experience in the ...
1993-10-06
Thermoregulatory responses of rats exposed to 9. 3-GHz radio-frequency radiation
Energy Technology Data Exchange (ETDEWEB)
Ketamine-anesthetized Sprague-Dawley rats were exposed in H orientation to far-field 9.3-GHz continuous-wave (CW) and pulsed (2 microseconds 500 pps) radiofrequency radiation (RFR) at average power densities of 30 and 60 mW/sq. cm (whole-body average specific absorption rates of 9.3 and 18.6 W/kg, respectively). Irradiation was conducted to cyclicly increase colonic temperature from 38.5 to 39.5 C. Colonic, tympanic, and subcutaneous temperatures, ECG, blood pressure, and respiratory rate were continuously recorded during experimentation. At both power densities, the subcutaneous and tympanic temperature increases significantly exceeded the colonic temperature increase. At both exposure levels, heart rate increased significantly during irradiation and returned to baseline when exposure was discontinued. Blood pressure and respiratory rate did not significantly change during irradiation. There were no significant differences between the effects of CW and pulsed RFR ...
1987-10-15
Terahertz time-domain spectroscopy of atmospheric water vapor from 0.4 to 2.7 THz.
Energy Technology Data Exchange (ETDEWEB)
We conducted broadband absorption measurements of atmospheric water vapor in the ground state, X {sup 1}A{sub 1} (000), from 0.4 to 2.7 THz with a pressure broadening-limited resolution of 6.2 GHz using pulsed, terahertz time-domain spectroscopy (THz-TDS). We measured a total of seventy-two absorption lines and forty-nine lines were identified as H{sub 2}{sup 16}O resonances. All the H{sub 2}{sup 16}O lines identified were confirmed by comparing their center frequencies to experimental values available in the literature.
2005-10-01
International Nuclear Information System (INIS)
In this paper, a time-domain equivalent circuit method is applied to solve dispersion of coupled-cavity travelling-wave tube (CCTWT). First, the time-domain circuit equations of CCTWT coupled-cavity chain are deduced from the equivalent circuit model. Then, the equations are solved numerically by fourth-order Runge-Kutta method and a program CTTDCP is developed using MATLAB. Last, a L-band CCTWT is calculated using CTTDCP and the cavity pass-band of this tube is computed to be 1.08-1.48 GHz, which is consistent with the experimental results and the simulation results of electromagnetic code and demonstrates the validity of the time-domain equivalent circuit method. In addition, a new design method which uses the equivalent circuit method and electromagnetic simulation together to optimize the cold cavity characteristics of CCTWT is proposed. (authors)
2008-09-01
Quantum secure direct communication by EPR pairs and entanglement swapping
We present a quantum secure direct communication scheme achieved by swapping quantum entanglement. In this scheme a set of ordered Einstein-Podolsky-Rosen (EPR) pairs is used as a quantum information channel for sending secret messages directly. After insuring the safety of the quantum channel, the sender Alice encodes the secret messages directly by applying a series local operations on her particle sequences according to their stipulation. Using three EPR pairs, three bits of secret classical information can be faithfully transmitted from Alice to remote Bob without revealing any information to a potential eavesdropper. By both Alice and Bob's GHZ state measurement results, Bob is able to read out the encoded secret messages directly. The protocol is completely secure if perfect quantum channel is used, because there is not a transmission of the qubits carrying the secret message between Alice and Bob in the public channel.
2004-03-01
Physiological changes in rats after exposure to low levels of microwaves
Energy Technology Data Exchange (ETDEWEB)
The effects of exposure to sublethal levels of microwaves were studied. Young albino rats of both sexes were exposed for 60 days to 7.5-GHz microwaves (1.0-KHz square wave modulation, average power 0.6 mW/cm2) for 3 h daily. During and after microwave exposure several physiological parameters were measured in both control and exposed animals. It was found that the animals exposed to microwaves tended to eat and drink less and thus showed a smaller gain in body weight. Some of the hematological parameters and organ weights were also significantly different. It is proposed that a nonspecific stress response due to microwave exposure and mediated through the central nervous system is responsible for the observed physiological changes.
1990-08-01
Monitoring transplanting operation of rice crop using passive microwave radiometer data
British Library Electronic Table of Contents (United Kingdom)
This study highlights a methodology to detect the transplanting operation of wetland rice at a regional scale using SSM/I brightness temperature in frequencies like 19, 37 and 85 GHz with vertical polarization. A cloud removal algorithm was used to make weekly composites of the brightness temperature, which were used to estimate the soil wetness index (SWI). Flooding of rice fields with water for transplanting induces very high change in SWI due to contrasting dielectric constant of water (80) and soil (4). Different weather conditions and fractional wet area under the footprint of sensor affect SWI, hence absolute value of SWI was not adequate. Therefore, multi-year SWI anomaly was used to generate a threshold value of SWI change to detect when SWI change between two consecutive weeks was...
2011-01-01
Microwave excitation of a CO/sub 2/ laser. Master's thesis
Energy Technology Data Exchange (ETDEWEB)
A flowing carbon dioxide laser was operated at low pressures up to 4 torr. Excitation of the laser was provided using various combinations of direct current (DC), pulsed microwave, and continuous wave (CW) microwave excitation. The microwaves were in the 2.45 GHz band and were coupled into the gas using a slow-wave interdigital transmission line. Laser output of 25 milliwatts (mw) was achieved using a DC discharge only. A combination of a DC discharge and pulsed microwaves doubled the output and resulted in some modulation. Changing the laser gas mixture and pulsed microwave field characteristics allowed some flexibility in the modulation. Lasing was not achieved with excitation from the CW microwaves alone due to the formation of localized discharges. Using pulsed microwaves to sustain the discharge and CW microwaves to pump the laser, a quasi-CW output of 55 mw was achieved.
1983-12-01
British Library Electronic Table of Contents (United Kingdom)
Cfiber/Si3N4 composites were prepared by hot-pressed sintering using a-Si3N4 powders, short carbon fibers and sintering additives as starting materials. The mechanical and dielectric properties of these composites were studied. When the short carbon fiber content of the composites increases from 0 to 1wt.%, the fracture toughness increases from 3.456 to 4.203MPam1/2, and both the real and imaginary part of permittivity increase greatly over the frequency range 8.2-12.4GHz. These effects were due to the anisotropy of short carbon fibers.
2007-01-01
Generation of number-phase minimum uncertainty states
Energy Technology Data Exchange (ETDEWEB)
The difference between the two nonclassical lights, i.e., the squeezed state and number-phase minimum uncertainty state (NUS) is discussed. The four different generation principles for NUS are described. They are: unitary evolution using self-phase modulation; nonunitary state reduction by the first kind measurement; controlled state reduction by quantum correlation measurement-feedback, and high saturated laser oscillation with suppressed-pump-noise. The constant current-driven semiconductor laser based on the last principle generated the NUS with photon number noise reduced below the standard quantum limit by 40 percent in the entire frequency region from dc to 1.1 GHz. Several applications of NUS including quantum communication, quantum mechanical computers and interferometric gravitational detection are discussed briefly. This presentation is represented by viewgraphs only.
1987-01-01
Energy Technology Data Exchange (ETDEWEB)
The transmission of electrical energy by use of underground cables is increasing. Fault location techniques have certain limitations; incipient fault detection and location would help reduce the maintenance cost of these lines as well as improve the reliability of service. The report discusses some test results related to RF-probing techniques applied to high-voltage transmission lines. The high-frequency losses and attenuation in high-voltage cables places certain ultimate limitations on RF-probing techniques for incipient fault detection. Time-domain reflectrometry methods were employed to assess the RF-transmission properties of high-voltage cables at frequencies as high as 6 GHz. Fast-Fourier-transform deconvolution was used to obtain loss measurements as a function of frequency. The loss mechanisms were identified. The measurement hardware and methods are discussed as well as analysis approach leading to the conclusions.
1986-04-01
Energy Technology Data Exchange (ETDEWEB)
Increased concern about potential health problems related to exposure to nonionizing electromagnetic fields (EMF) has occurred recently. The most recent epidemiological studies have dealt mainly with effects of extremely low frequency EMF on fetal development and cancer. This paper summarizes noteworthy aspects or recent reviews and studies in this area of research. There has been increased concern recently about potential health problems related to exposure to nonionizing electromagnetic fields (EMF). Although some questions have been raised concerning exposure to radiofrequency radiation (at frequencies up to 300 GHz), the major focus has been on fields of extremely low frequency (especially 60 Hz). The most recent epidemiologic studies have dealt mainly with effects of extremely-low-frequency EMF on fetal development and with the initiation or promotion of cancer.
1991-12-31
A principle of charged particle trapping by RF electromagnetic field in the spherical cavity
Energy Technology Data Exchange (ETDEWEB)
A new principle of particle trapping in the simple spherical cavity using both electric and magnetic components of radiofrequency electromagnetic field is proposed. The electric component of H {sub 12} oscillating mode drives the fast particle oscillations, while the magnetic component synchronously bends the trajectories to the cavity center. A specially developed theory of particle stability predicts dense and energetic electron cluster in the trap. Numerical simulations of particle dynamics in the complete electromagnetic field taking into account both space charge and particle-induced magnetic field are in good agreement with the analytic results, giving a density of 2.6*10{sup 1} electrons/cm{sup 3} and an average kinetic energy of around 30 keV at an operating frequency of 3 GHz. Being used at lower frequency, spherical cavity can trap protons and heavier ions too, but with lower density and kinetic energy.
2005-11-21
Thermal action of 2. 45 GHz microwaves on the cytoplasm of Chinese hamster cells
Energy Technology Data Exchange (ETDEWEB)
In order to demonstrate possible specific effects of microwaves at the cellular level V-79 Chinese hamster cells were exposed to 2.45-GHz radiation at power levels of 20-200 mW/cm2 and at specific absorption rates of 10-100 mW/g. Intracellular cytoplasmic changes were observed by fluorescence polarization using a method based on the intracellular enzymatic hydrolysis of nonfluorescent fluorescein diacetate (FDA). At levels of absorbed energy below 90 J/g, modifications of microviscosity and mitochondrial state were absent, but a slight stimulation of enzymatic hydrolysis of FDA was observed which may be explained by microwave-induced alterations of cellular membranes possibly due to differences in heating pattern of microwaves compared to water-bath heating. At levels of absorbed energy above 90 J/g, the decrease of enzymatic hydrolysis of FDA, increase in degree of polarization, and increase of permeation of the fluorescent marker correlated well with the decrease ...
1984-01-01
SUBMILLIMETER ARRAY OBSERVATIONS TOWARD THE MASSIVE STAR-FORMING CORE MM1 OF W75N
International Nuclear Information System (INIS)
The massive star-forming core MM1 of W75N was observed using the Submillimeter Array with #approx#1'' and 2'' spatial resolutions at 217 and 347 GHz, respectively. From the 217 GHz continuum we found that the MM1 core consists of two sources, separated by about 1'': MM1a (#approx#0.6 M_s_u_n) and MM1b (#approx#1.4 M_s_u_n), located near the radio continuum sources VLA 2/VLA 3 and VLA 1, respectively. Within MM1b, two gas clumps were found to be expanding away from VLA 1 at about #+-#3 km s"-"1, as a result of the most recent star formation activity in the region. Observed molecular lines show emission peaks at two positions, MM1a and MM1b: sulfur-bearing species have emission peaks toward MM1a, but methanol and saturated species at MM1b. We identified high-temperature (#approx#200 K) gas toward MM1a and the hot core in MM1b. This segregation may result from the evolution of the massive star-forming core. In the very early phase of star ...
2010-11-10
Radiofrequency electromagnetic fields in the Cookridge area of Leeds
Energy Technology Data Exchange (ETDEWEB)
On the 8 and 9 May 2002 representatives of the National Radiological Protection Board (NRPB) performed a radiofrequency electromagnetic field survey in the Cookridge area of Leeds in order to assess exposure to radio signals from transmitters mounted on a water tower/a lattice tower and a radio station tower. Guidelines on limiting exposure to radio signals have been published by NRPB and the International Commission on Non-Ionizing Radiation Protection (ICNIRP). These guidelines are designed to prevent established adverse effects on human health. During this survey, the total exposures due to all radio signals from 30 MHz to 18000 MHz (18 GHz) were measured. This frequency range was chosen as it includes mobile phone base station transmissions, which are at around 900 and 1800 MHz and super high frequency (SHF) transmissions from most of the large microwave dish antennas mounted on the towers. In addition, other major sources of radiofrequency electromagnetic ...
2002-07-01
Quantum dots for lasers, amplifiers and computing
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. ...
2005-07-07
Energy Technology Data Exchange (ETDEWEB)
The Two-Beam Accelerator (TBA) consists of a long high-gradient accelerator structure (HGS) adjacent to an equal-length Free Electron Laser (FEL). In the FEL, a beam propagates through a long series of undulators. At regular intervals, waveguides couple microwave power out of the FEL into the HGS. To replenish energy given up by the FEL beam to the microwave field induction accelerator units are placed periodically along the length or the FEL. In this manner it is expected to achieve gradients of more than 250 MV/m and thus have serious option for a 1 TeV /times/ 1 TeV linear collider. The state of present theoretical understanding of the TBA is presented with particular emphasis upon operation of the ''steady-state'' FEL, phase and amplitude control of the rf wave, and suppression of sideband instabilities. Experimental work has focused upon the development of a suitable HGS and the testing of this structure using the Electron Laser Facility (ELF). ...
1987-08-01
The Brazilian spherical detector: progress and plans
International Nuclear Information System (INIS)
We are building the Schenberg gravitational wave detector at the Physics Institute of University of Sao Paulo as programmed by the Brazilian Graviton Project. The antenna and its vibration isolation system are already built, and we have made a first cryogenic run for an overall test, in which we measured the antenna mechanical Q (figure of merit). We also have built a 10.21 GHz oscillator with phase noise performance better than -120 dBc at 3.2 kHz to pump an initial CuAl6% two-mode transducer. We plan to prepare this spherical antenna for a first operational run at 4.2 K with a single transducer and an initial target sensitivity of h #approx# 2 x 10"-"2"1 Hz"-"1"/"2 in a 50 Hz bandwidth around 3.2 kHz soon. Here we present details of this plan and some recent results of the development of this project.
2004-03-07
Radial distribution of superthermal electrons measured with ECE (abstract)
International Nuclear Information System (INIS)
To aid in the study of lower hybrid current drive as a means of current profile control, the radial profile and velocity distribution of the fast current-carrying electrons and their time evolution must be known. As part of the recent effort to understand this fast electron transport, a diagnostic has been installed on PBX-M to measure the electron cyclotron emission from the fast electrons. An oblique horizontal view of upshifted cyclotron emission in the midplane can give radial as well as velocity space information about the fast electrons. Emission in X mode frequencies refracted by the right-hand cutoff is radially localized. The observed emission at a specific frequency comes only from the radial region r_t_u_r_n=#0. Emission measured by this new diagnostic has been found to be radially localized as predicted. It is also expected that localized moments of the distribution function may be obtained from these data. A superheterodyne receiver at 60--90 GHz has ...
0854-01-01
Pulse compression in a free electron laser amplifier
International Nuclear Information System (INIS)
We have studied both theoretically and experimentally a new scheme of active pulse compression in a free electron laser (FEL) amplifier. The pulse compression scheme presented here is the following. A frequency-chirped pulse is injected into the FEL interaction region. Because of the high gain and narrow bandwidth of the FEL interaction, only the resonant frequency band of the pulse is actively amplified, resulting in a short pulse of high power coherent radiation at the output of the laser. For our experimental parameters (beam voltage #approx =# 150 kV, current #approx =# 5.0 A, wiggler period #approx =# 3.5 cm and gain #approx =# 10 dB), pulses of a few nanoseconds were generated at #approx =# 10 GHz after an interaction length of 2.30 m, in good agreement with theoretical expectations. For the same input pulses (width > 100 ns, frequency chirp #alpha#/2#pi# #approx =# 5 MHz/ns), the obtention of such compression ratios would require hundreds of meters of ...
PSDE/SAT-2: Communication system architecture study, executive summary
The PSDE/SAT-2 multimission satellite designed to offer a flight opportunity to different experimental communication payloads and verify the feasibility of advanced space technologies is described. It was conceived for expriment in the framework of the European DRS (Data Relay Satellite) program thus providing intersatellite and interorbit communication links, but also experimental and preoperative services. Payloads include optical communication single access payload (LSA); S-Band single access payload; S-Band multiple access payload; land mobile experimental payload; navigation payload; 40/50 GHz communication payload; and millimeter wave propagation payload. The orbital slot and interference analysis identified a limited number of orbital positions for the mission interleaved between Eutelsat satellites (i.e., 14 deg 30 min E and 17 deg 30 min E). A coordination is required in Ku-Band with Eutelsat satellites and in Ka-Band with ITALSAT (Italy) and TOR-12 (USSR) ...
1988-01-01
Mode-locked YAG-Nd ring laser with unidirectional stimulated emission
Energy Technology Data Exchange (ETDEWEB)
The traveling-wave mode in ring lasers is achieved by two methods: by a reversing mirror, and by using an intracavity nonreciprocal device. This paper is devoted to realization of the traveling-wave mode in a mode-locked YAG-Nd ring laser by a method proposed by Tomov et al. This method uses two intracavity Q-switches. In mode-locked operation, pulses are generated that can be considered short compared with the period of modulation T = L/C (where L is the length of the perimeter of the cavity). Analysis shows that if the shift of the switching signals corresponds to the time of travel of a light pulse between Q-switches, the pulse in one direction will pass the Q-switches at instants of zero losses, while losses in the other direction will be maximized for a distance between Q-switches of L/4, and will be zero for a distance L/2. Experimental verification of the proposed method gave unidirectional lasing with an intensity ratio in the two directions of at least 600:1, the intensity of ...
1981-05-01
Energy Technology Data Exchange (ETDEWEB)
The paper reported on an experiment on measurement of concentration of highly concentrated coal slurry using microwaves carried out at Miike coal preparation works. The purpose of the experiment was to investigate applicability of microwave moisture content measurement of slurry of a mixture of coal and coal particles and to use it to the control of process such as coal preparation and processing. In the experiment, a method for measuring the slurry concentration was adopted in which the container filled with highly concentrated coal slurry was irradiated with microwaves and the damping of strength of the penetrating microwaves was detected. As a result of the experiment, it was found out that there was a big correlation between the capacitive concentration of slurry and the damping ratio of microwaves. When irradiating slurry with microwaves of 1GHz frequency, a big correlation between the concentration and the damping ratio was seen in capacitive concentration of ...
1996-09-30
Limits on the Diffuse Radio and Hard X-ray Emission of Abell 2199
The Westerbork Northern Sky Survey (WENSS) and the NRAO/VLA Sky Survey (NVSS) were used to determine an upper limit to the diffuse radio flux from the nearby cluster Abell 2199. For the entire cluster, this limit is <3.25 Jy at 327 MHz from WENSS; for the inner 15' radius, the limit is <168 mJy at 1.4 GHz. These limits are used to constrain the cluster magnetic field by requiring that the radio flux be consistent with the hard X-ray (HXR) flux observed by BeppoSAX, assuming that the observed HXR excess is due to inverse Compton (IC) scattering of cosmic microwave background photons by relativistic electrons in the intracluster gas. We find that the magnetic field must be very weak (<0.073 uG) in order to avoid producing an observable radio halo. We also consider the possibility that the HXR excess is due to nonthermal bremsstrahlung (NTB) by a population of suprathermal electrons which are being accelerated to higher energies. We find that a NTB model ...
1999-01-01
High field ESR of P-doped Si for Quantum Computing Application
Energy Technology Data Exchange (ETDEWEB)
We measured ESR of phosphorous-doped silicon with a low concentration of P, n, at high magnetic fields and low temperatures to investigate the states of nuclear spin. A sample with n = 6.52 x 10{sup 16} /cm{sup 3} was studied at 2.85 T (80 GHz) from 30 K to 2.3 K by field-modulating cw-ESR for a fixed 0 dB power. As the temperature was lowered, the out-of-phase signal appeared around 18 K, reached at a maximum intensity at 13 K, and disappeared around 6 K. The out-of-phase signal is referred to the field modulation. The in-phase signal started to change from the derivative of absorption spectrum at high temperatures to absorption-like shape around 15 K and asymmetry of intensity for two peaks of hyperfine-separated signals increased as temperatures was lowered. Below 10 K, the saturation of the in-phase signal started to appear. We speculate that the asymmetry is caused by saturation effect and dynamic nuclear polarization of {sup 31}P nuclear spin due to drastic ...
2009-02-01
Fast Implementation of Matched Filter Based Automatic Alignment Image Processing
Energy Technology Data Exchange (ETDEWEB)
Video images of laser beams imprinted with distinguishable features are used for alignment of 192 laser beams at the National Ignition Facility (NIF). Algorithms designed to determine the position of these beams enable the control system to perform the task of alignment. Centroiding is a common approach used for determining the position of beams. However, real world beam images suffer from intensity fluctuation or other distortions which make such an approach susceptible to higher position measurement variability. Matched filtering used for identifying the beam position results in greater stability of position measurement compared to that obtained using the centroiding technique. However, this gain is achieved at the expense of extra processing time required for each beam image. In this work we explore the possibility of using a field programmable logic array (FPGA) to speed up these computations. The results indicate a performance improvement of 20 using the FPGA relative to a 3 ...
2008-04-02
Electromagnetic radiation unmasked
International Nuclear Information System (INIS)
This article describes the nature of the electromagnetic waves, what they are and how do they affect us. Current concern is focused on exposure to low level power-frequency magnetic fields like microwave radiation from mobile phones and leaking microwave ovens; high power radiation from defence and airport radars; fields close to high voltage transmission lines; radio frequency fields from industrial welders and heaters and DC magnetic fields in aluminium smelters. These fields with frequency less than 300 GHz do not carry sufficient energy to break chemical bonds and it is assumed that they cannot damage cell DNA. The amount of radiation absorbed by a human exposed to far field electromagnetic radiation (EMR) depends on the orientation and size of the person. In the 30-300 MHz range it is possible to excite resonance in the whole or partial body such as the head. It is emphasised that since there are some evidence that electromagnetic fields do harm, a policy of ...
1996-01-01
Electromagnetic fields and cancer: how ICNIRP has dealt with the issue
International Nuclear Information System (INIS)
Whether exposure to electromagnetic fields (EMFs) cause cancer has been vigorously debated for many years and has been the most vexing issue with which ICNIRP has had to deal during its short existence. There have been three parts of the electromagnetic spectrum that the issue of cancer has raised: static (0 Hz) magnetic fields, extremely low frequency (ELF) fields (defined as > 0-300 Hz, but concerns have been raised almost exclusively at the power frequencies of 50/60 Hz), and radiofrequency (RF) fields (300 Hz -300 GHz). By far the major problems have arisen during the construction of new high voltage transmission lines and mobile telephone systems. Actions by protest groups concerned with possible health effects, especially with cancer in children, has now reached such a scale that it is costing electrical utilities and communications companies billions of dollars annually world-wide. With such high stakes, ICNIRP has had to be extremely careful in its ...
1996-04-01
EPR investigation of some traditional oriental irradiated spices
International Nuclear Information System (INIS)
The 9.50 GHz electron paramagnetic resonance (EPR) spectra of unirradiated and "6"0Co #gamma#-ray irradiated cardamom (Elettaria cardamomum L. Maton, Zingiberaceae), ginger ((Zingiber officinale Rosc., Zingiberaceae), and saffron (Crocus sativus L., Iridaceae) have been investigated at room temperature. All unirradiated spices presented a weak resonance line with g-factors around free-electron ones. After #gamma#-ray irradiation at an absorbed dose of up to 11.3 kGy, the presence of EPR spectra whose amplitude increase monotonously with the absorbed dose has been noticed with all spices. A 100 "oC isothermal annealing of 11.3 kGy irradiated samples has shown a differential reduction of amplitude of various components that compose initial spectra, but even after 3.6 h of thermal treatment, the remaining amplitude represents no less then 30% of the initial ones. The same peculiarities have been noticed after 83 days storage at room temperature but after 340 days ...
2007-06-01
Complex permittivity and complex permeability of Sr ions substituted Ba ferrite at X-band
International Nuclear Information System (INIS)
M-type hexagonal ferrite composition, Ba(1-x)SrxFe12O19 (x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0), was prepared by a two route ceramic method. Complex permittivity (?'-j?'') and complex permeability (?'-j?'') have been measured using a network analyzer from 8.2 to 12.4 GHz X-ray diffraction confirmed the M-type hexagonal structure and a scanned electron micrograph was used to analyze the grain size distribution of ferrite. Substitution of Sr2+ ions causes an increase in porosity that deteriorates the electromagnetic and microstructural properties in the doped samples. Both dielectric constant and dielectric loss are enhanced in comparison to the permeability and magnetic loss over the entire frequency region. This is due to a resistivity variation and the formation of Fe2+ ions, which increases the hopping mechanism between Fe2+ and Fe3+ ions.
2008-05-01
Energy Technology Data Exchange (ETDEWEB)
A newly constructed Fourier transform microwave spectrometer has been used to record the pure rotational spectra of four isotopomers of SrS ({sup 88}Sr{sup 32}S, {sup 87}Sr{sup 32}S, {sup 86}Sr{sup 32}S, and {sup 88}Sr{sup 34}S) between 6 and 26 GHz. The molecules were produced by reacting laser ablated strontium with carbonyl sulfide (0.1% in argon). Pure rotational transitions in the ground, first and second vibrational states have been observed. The data set has enabled a multi-isotopomer fit. Born-Oppenheimer breakdown terms for both atoms have been determined. The {sup 87}Sr nuclear quadrupole coupling constant in {sup 87}Sr{sup 32}S has been determined for the first time.
2007-12-06
Energy Technology Data Exchange (ETDEWEB)
The influence of low-level microwaves (2.45 GHz, CW, 2 and 5 mW.cm/sup -2/) was studied on various models of previsional animal psychopharmacology involving tests of motor activity, stereotypy, convulsions and hypothermia after a standard 30 min irradiation. The results obtained on 933 rodents allow to conclude that: (1) there is no interaction between microwaves and the studied convulsants and stimulants; (2) there is a possibility of potentialization of the behavioral effects of a tranquilizer; (3) there is a thermogenic effect of microwaves; (4) there is no change of the blood-brain barrier permeability. The demonstration of a thermal effect of microwaves during radiations lower than 10 mW.cm/sup -2/ the safety threshold admitted presently (a value below which the exposure duration comes under regulation) could explain the energetic nature of certain effects of microwaves up-to-now described as non-thermal.
1982-01-01
Air breakdown induced by a high-power short-pulse microwave
Energy Technology Data Exchange (ETDEWEB)
At Himeji Institute of Technology, the high power microwaves with the peak power of 20 MW, frequency of 12 GHz and pulse duration of 14 ns have been produced with a virtual cathode oscillator (vircator). These high power microwaves offer new applications in various fields. One problem in laser-triggered lightning experiment is the strong attenuation of laser energy by rain, cloud and laser-produced plasma. Microwaves propagate in thundercloud with small loss, and also are able to irradiate much extensive region of targets. In this paper, the fundamental experiment on the air breakdown induced by high power, short pulse microwaves is reported. The experimental setup of the vircator diode for microwave generation is shown. The typical evolution of diode voltage, electron beam current and microwave emission from the top in the course of time is shown. The experimental setup for microwave-induced air breakdown and the experimental procedure are explained. The results ...
1996-05-01
A gas-jet ECR ion source at TRIGA-SPEC
International Nuclear Information System (INIS)
The TRIGA-SPEC experiment has been installed recently at the research reactor TRIGA Mainz. Ground state properties like masses, charge radii, spins, and moments of short-lived nuclides can be determined with very-high precision using the Penning trap mass spectrometer TRIGA-TRAP, and the collinear laser spectroscopy setup TRIGA-LASER. Short-lived neutron-rich radionuclides in the mass range 80 < A < 140 are produced by thermal neutron induced fission of e.g. U-235, Pu-239 or Cf-249, respectively. For the extraction and ionization of the fission products a gas-jet system is coupled to a 2.45-GHz ECR ion source for the production of singly charged ions. The gas-jet has been tested on-line and fission products have been extracted. First off-line tests of the ion source have been performed successfully with argon gas. The results of the commissioning test of the ion source and the on-line coupling of the experiments are presented.
2010-03-08
Theory of low voltage annular beam free-electron lasers
Energy Technology Data Exchange (ETDEWEB)
An nonlinear analysis of an annular beam propagating through a cylindrical waveguide in the presence of a helical wiggler and an axial guide field is presented. The analysis is based upon the ARACHNE simulation which is a non-wiggler-averaged slow-time-scale simulation code in which the electromagnetic field is represented as a superposition of the TE and TM modes in a vacuum waveguide, and the beam space-charge waves are represented as a superposition of Gould-Trivelpiece modes. The DC self-electric and self-magnetic fields are also included in the model. ARACHNE has been extensively benchmarked against experiments at MIT and NRL in the past with good agreement, but all of these experiments have dealt with solid electron beams and beam voltages in excess of 200 kV. In seeking to reduce the beam voltage requirements we now consider the effect of operation with an annular beam. One advantage to be obtained by using an annular beam is that, for a fixed beam current, the effect of the DC ...
1995-12-31
Recent Korean R&D in Satellite Communications
The R&D in satellite communications in Korea has been driven mainly by KCC (Korea Communications Commission) but in a small scale compared to Korea space development program organized by MEST (Ministry of Education, Science and Technology). Public and civilian satcom sector R&D has been led mainly by ETRI with small/medium companies contrary to rare investment in private sector while military sector R&D has been orchestrated by ADD with defense industry. By the COMS (Communication, Ocean and Meteorological Satellite) experimental Ka-band payload, Korea pursues a space qualification of own technology for national infrastructure evolution as well as industrialization of space R&D results. Once COMS launched and space qualified in 2009, subsequent application experiments and new technology R&D like UHDTV will entail service and industry promotion. The payload technology is expected for the next Korean commercial satellites or for new OBP satellites. The COMS ground ...
2009-01-01
International Nuclear Information System (INIS)
We report on the ultraviolet laser absorption spectroscopy of atomic Gd at 394-554 nm where two transition lines are place very closely by using a frequency-doubled beam of external-cavity diode laser (ECDL). One is from 999.121 to 26337.071 cm-1 and the other from 0 to 25337.755 cm-1. If two transition lines are placed closely within a continuous fine tuning range, the real-time measurement of the atomic excitation temperature is possible without any significant time consumption because at least two transition lines originating from different low-lying energy levels need to be investigated for the Boltzmann-plot. Since the spectral difference between the two transitions is only about 0.195 cm-1 (5.85 GHz), it is possible to record both the absorption spectra simultaneously as shown in Fig. 1. But the transition probabilities (or oscillator strengths) of these lines have not been measured accurately yet to the best of our knowledge. We report on the newly measured ...
2003-11-07
Energy Technology Data Exchange (ETDEWEB)
Free-electron laser (FEL) experiments have been conducted with the 38-MeV L-band electron linac at the Institute of Scientific and Industrial Research, Osaka University. It is a 1.3 GHz RF linac with a thermoionic gun, and equipped with two 12th and one 6th sub-harmonic prebunchers for producing the high-intensity single-bunch beam with a charge up to 67 nC/bunch. For oscillation experiments of FEL, the gun is replaced with that with a smaller cathode area in order to reduce the emittance of the beam. The normalized emittance has been measured to be 200 {pi} mm-mrad. The linac is operated in the long-pulse mode and one of the 12th sub-harmonic bunchers and the 6th sub-harmonic buncher are operated, so that the time duration of the macropulse is 4 {mu}s and the spacing between micropulses is 9.2 ns. The length of the micropulse is 30-40 ps and the charge in each micropulse is 2 nC. The electron beam from the linac is transported to a wiggler which has the period ...
1995-12-31
Implementation of Accelerated Beam-Specific Matched-Filter-Based Optical Alignment
Energy Technology Data Exchange (ETDEWEB)
Accurate automated alignment of laser beams in the National Ignition Facility (NIF) is essential for achieving extreme temperature and pressure required for inertial confinement fusion. The alignment achieved by the integrated control systems relies on algorithms processing video images to determine the position of the laser beam images in real-time. Alignment images that exhibit wide variations in beam quality require a matched-filter algorithm for position detection. One challenge in designing a matched-filter based algorithm is to construct a filter template that is resilient to variations in imaging conditions while guaranteeing accurate position determination. A second challenge is to process the image as fast as possible. This paper describes the development of a new analytical template that captures key recurring features present in the beam image to accurately estimate the beam position under good image quality conditions. Depending on the features present in a particular beam, ...
2009-01-29
Energy Technology Data Exchange (ETDEWEB)
This progress report consists of an article, the abstract of which follows, and apparently the references and vita from a proposal. A review of perturbation diagnostics applied to microwave resonant cavity discharges is presented. The classical microwave perturbation technique examines the shift in the resonant frequency and cavity quality factor of the resonant cavity caused by low electron density discharges. However, modifications presented here allow the analysis to be applied to discharges with electron densities beyond the limit predicted by perturbation theory. An {open_quote}exact{close_quote} perturbation analysis is presented which models the discharge as a separate dielectric, thereby removing the restrictions on electron density imposed by the classical technique. The {open_quote}exact{close_quote} method also uses measurements of the shifts in the resonant conditions of the cavity. Thirdly, an electromagnetic analysis is presented which uses a characteristic equation, ...
1992-12-31
Abnormal cardiovascular responses induced by localized high power microwave exposure
Energy Technology Data Exchange (ETDEWEB)
A hypothesis of microwave-induced circulatory under perfusion was tested in ketamine anesthetized rats whose heart rate, mean arterial pressure, pulse pressure, respiration rate, and body temperatures were monitored continuously. Fifty-eight ventral head and neck exposures in a waveguide consisted of sham-exposure and exposure to continuous wave (CW) and pulsed 1.25 GHz microwaves for 5 min. The 0.5 Hz and 16 Hz pulsemodulated microwaves were delivered at 400 kW peak power. The CW microwaves were 2 and 6.4 W. The average specific absorption rate was 4.75 W/kg per watt transmitted in the brain and 17.15 W/kg per watt transmitted in the neck. Respiration rate and mean arterial pressure were not altered. Changes in heart rate and pulse pressure were observed in rats exposed to higher power but not to the lower average power microwaves. Depression of pulse pressure, an indication of a decrease in stroke volume, and increased or decreased heart rate were noted in ...
1992-05-01
A high-power millimeter-wave sheet beam free-electron laser amplifier
International Nuclear Information System (INIS)
The results of experiments with a short period (9.6 mm) wiggler sheet electron beam (1.0 mm x 2.0 cm) millimeter-wave free electron laser (FEL) amplifier are presented. This FEL amplifier utilized a strong wiggler field for sheet beam confinement in the narrow beam dimension and an offset-pole side-focusing technique for the wide dimension beam confinement. The beam analysis herein includes finite emittance and space-charge effects. High-current beam propagation was achieved as a result of extensive analytical studies and experimental optimization. A design optimization resulted in a low sensitivity to structure errors and beam velocity spread, as well as a low required beam energy. A maximum gain of 24 dB was achieved with a 1-kW injected signal power at 86 GHz, a 450-kV beam voltage, 17-A beam current, 3.8-kG wiggler magnetic field, and a 74-period wiggler length. The maximum gain with a one-watt injected millimeter-wave power was observed to be over 30 dB. The ...
On the impact of low power density microwaves in some living tissues
Energy Technology Data Exchange (ETDEWEB)
The biomedical and ecological interest for the microwave impact on the Earth biosphere is continuously increased since the industrial, military and communication activities strongly contribute to the electromagnetic stress of living bodies. In the next the authors present some of the main results obtained regarding the microwave exposure of various types of biological material: bacteria, fungi, young plant seedlings, dry seeds, animal tissues. The electromagnetic exposure was carried out in open space in well controlled environmental conditions by using 10.75 GHz/1 m W cm{sup -2} microwaves. Biochemical assays and cytogenetic tests have been carried out to reveal the changes induced post irradiation. The response of some pathogen bacteria, have been emphasized by means of turbidimetric measurements - the stimulatory effect being noticed at the level of the microbial population density (the stimulation of the human body microbial flora seems to be one of the side ...
2006-07-01
Review of JT-60U experimental results from February to October, 1999
International Nuclear Information System (INIS)
In 1999, the plasma parameters of reversed shear (RS) plasmas had been extended in 1) DT-equivalent fusion power gain Q_D_T"e"q - 0.5 (n_D(0)#tau#_ET_i(0) - 4x10"2"0 m"-"3#centre dot#keV#centre dot#s) for 0.8 s and 2) full non-inductive current drive with 80% of the bootstrap current fraction. Physics of the internal transport barriers (ITBs) in RS plasmas, including the energy transport and the formation of ITB, were extensively studied. A nearly full current drive (92% non-inductively) was obtained with negative ion based neutral beam (NNB) injection (360 keV, 3.4 MW) in a high #beta#_p H-mode plasma (I_p=1.5 MA, B_T=3.7 T, q_9_5=4.2) with high plasma performance (#beta#_N=2.4 and H_8_9=2.56). Rise in the central electron temperature (T_e - 9 keV) resulted in the current drive efficiency #eta#_C_D of NNB reached 1.3x10"1"9 A/W/m"2, the highest for the neutral beam current drive. As for the H-mode plasmas, decrease in the pedestal ion temperature due to strong gas was found cause ...
1994-06-01
Quantum information processing in nanostructures[Quantum optics; Quantum computing
Energy Technology Data Exchange (ETDEWEB)
Since information has been regarded os a physical entity, the field of quantum information theory has blossomed. This brings novel applications, such as quantum computation. This field has attracted the attention of numerous researchers with backgrounds ranging from computer science, mathematics and engineering, to the physical sciences. Thus, we now have an interdisciplinary field where great efforts are being made in order to build devices that should allow for the processing of information at a quantum level, and also in the understanding of the complex structure of some physical processes at a more basic level. This thesis is devoted to the theoretical study of structures at the nanometer-scale, 'nanostructures', through physical processes that mainly involve the solid-state and quantum optics, in order to propose reliable schemes for the processing of quantum information. Initially, the main results of quantum information theory and quantum computation are ...
2002-07-01
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