WorldWideScience

Sample records for cavity receivers

  1. Thermal Model of a Dish Stirling Cavity-Receiver

    Directory of Open Access Journals (Sweden)

    Rubén Gil

    2015-01-01

    Full Text Available This paper presents a thermal model for a dish Stirling cavity based on the finite differences method. This model is a theoretical tool to optimize the cavity in terms of thermal efficiency. One of the main outcomes of this work is the evaluation of radiative exchange using the radiosity method; for that purpose, the view factors of all surfaces involved have been accurately calculated. Moreover, this model enables the variation of the cavity and receiver dimensions and the materials to determine the optimal cavity design. The tool has been used to study the cavity optimization regarding geometry parameters and material properties. Receiver absorptivity has been identified as the most influential property of the materials. The optimal aperture height depends on the minimum focal space.

  2. Radiometric measurement of temperature distributions in solar cavity receivers

    Science.gov (United States)

    Thacher, E. F.; Giannola, P. S.

    1989-03-01

    An engineering tool incorporating a scanning infrared radiometer, an image digitizer, a microcomputer, and the software to drive the system was developed to allow remote mapping of the temperature distribution in solar cavity receivers. Using enclosure analysis, the infrared image processing program extracts the irradiance map from the radiosity map of the cavity to yield an emissive power map. Using the calibration curve of the radiometer and the emissivity of the surface of the cavity, the emissive power map is transformed into a temperature map. The system was tested by comparing its calculated temperatures to temperatures measured by thermocouples at several locations on the surfaces of heated model cavity receivers. The average relative error for the cavities ranged from 4.6 percent to 34.9 percent, with the relative error on the base usually less than half that on the wall. Some work was also carried out to compensate the detected radiosity field for the system transfer function error of the scanner system.

  3. Design of a cavity heat pipe receiver experiment

    Science.gov (United States)

    Schneider, Michael G.; Brege, Mark H.; Greenlee, William J.

    1992-01-01

    A cavity heat pipe experiment has been designed to test the critical issues involved with incorporating thermal energy storage canisters into a heat pipe. The experiment is a replication of the operation of a heat receiver for a Brayton solar dynamic power cycle. The heat receiver is composed of a cylindrical receptor surface and an annular heat pipe with thermal energy storage canisters and gaseous working fluid heat exchanger tubes surrounding it. Hardware for the cavity heat pipe experiment will consist of a sector of the heat pipe, complete with gas tube and thermal energy storage canisters. Thermal cycling tests will be performed on the heat pipe sector to simulate the normal energy charge/discharge cycle of the receiver in a spacecraft application.

  4. The ADMX Sidecar cavity and receiver-chain

    Science.gov (United States)

    Boutan, Christian; ADMX Collaboration

    2015-04-01

    The Axion Dark Matter eXperiment (ADMX) searches for dark-matter axions by looking for their resonant conversion to microwave photons in a strong magnetic field. If ADMX rules out axions in the 500 MHz - 2 GHz frequency range, new technologies and cavity geometries will need to be explored to find higher mass axions. ADMX Sidecar is a higher frequency pathfinder experiment that uses a miniature resonant cavity to search for axions in the 2 GHz - 10 GHz frequency range. The Sidecar cavity shares the magnetic field and cryogenics of the main experiment but the data pipeline and receiver-chain are new and independent of the existing infrastructure. Unlike the main experiment, which uses gear-boxes and fiberglass shafts to translate the motion of room temperature motors into the cryogenic space, piezoelectric motors are used to adjust the Sidecar tuning rod position and antenna depth. Here I discuss the design, construction and status of ADMX Sidecar. Supported by DOE Grants DE-FG02-97ER41029, DE-FG02-96ER40956, DE- AC52-07NA27344, DE-AC03-76SF00098, NSF Grant 1067242, and the Livermore LDRD program.

  5. Solar heated-air cavity receiver development (SHARE)

    Energy Technology Data Exchange (ETDEWEB)

    Jarvinen, P. O.

    1978-01-01

    Studies of advanced receivers for solar thermal heated-air Brayton power systems have been under way at MIT/Lincoln Laboratory since 1975 and have shown that the ceramic domed cavity receiver concept is a promising approach for central receiver systems. Development of the novel ceramic receiver concept, which heats pressurized gas to 1800/sup 0/F (1000/sup 0/C) for use with gas turbine units, has been proceeding under Department of Energy sponsorship since May 1978. The advanced development program is focused on the solution of technologically pacing items in the receiver; for instance, the development of a high-temperature seal between the pressurized air and high-temperature ceramic dome material. Progress made on a number of elements in the development program including ceramic dome stress calculations, metalization of ceramics, selection of a preferred receiver/dome sealing approach, and mechanical seal leak measurement is discussed. The continuing experimental program to develop and demonstrate seals on ceramic domes to one-foot diameter is described.

  6. Thermal modeling of a pressurized air cavity receiver for solar dish Stirling system

    Science.gov (United States)

    Zou, Chongzhe; Zhang, Yanping; Falcoz, Quentin; Neveu, Pierre; Li, Jianlan; Zhang, Cheng

    2017-06-01

    A solar cavity receiver model for the dish collector system is designed in response to growing demand of renewable energy. In the present research field, no investigations into the geometric parameters of a cavity receiver have been performed. The cylindrical receiver in this study is composed of an enclosed bottom at the back, an aperture at the front, a helical pipe inside the cavity and an insulation layer on the external surface of the cavity. The influence of several critical receiver parameters on the thermal efficiency is analyzed in this paper: cavity inner diameter and cavity length. The thermal model in this paper is solved considering the cavity dimensions as variables. Implementing the model into EES, each parameter influence is separately investigated, and a preliminary optimization method is proposed.

  7. Study of heat transfer through a cavity receiver for a solar powered advanced Stirling engine generator

    International Nuclear Information System (INIS)

    Hussain, T.; Islam, M.D.; Kubo, I.; Watanabe, T.

    2016-01-01

    Stirling engine operated by concentrated solar energy can be a great mean to generate power. Highly concentrated solar radiations with minimum heat loss from cavity receiver are required to operate the Stirling engine. Therefore, heat transfer study of the cavity receiver is required for the maximum utilization of solar energy with minimum heat losses for the efficient Stirling engine generator. In this study, experiments were performed to find the most suitable cavity receiver configuration for maximum solar radiation utilizations by an Advanced Stirling Engine Generator (ADSEG). Dimensionless parameter: aperture ration (AR = d/D) and aperture position (AP = H/D) were used to characterize the different configurations of cylindrical cavity receiver. Experimental heat loss analysis (Convection, radiation and total heat loss) as well as air film temperature profiles along the wall height (H) of the receiver for different configurations of the cavity receiver was performed in this experiment for its selection. Based on experimental results, among the four different configurations of cylindrical cavity receiver, Type IV (AR = 0.5 AP = 0.53) was found to be the most suitable receiver for the ADSEG system.

  8. Experimental and numerical analysis of convective heat losses from spherical cavity receiver of solar concentrator

    Directory of Open Access Journals (Sweden)

    Shewale Vinod C.

    2017-01-01

    Full Text Available Spherical cavity receiver of solar concentrator is made up of Cu tubing material having cavity diameter 385 mm to analyze the different heat losses such as conduction, convection and radiation. As the convection loss plays major role in heat loss analysis of cavity receiver, the experimental analysis is carried out to study convective heat loss for the temperature range of 55-75°C at 0°, 15°, 30°, 45°, 60°, and 90° inclination angle of downward facing cavity receiver. The numerical analysis is carried out to study convective heat loss for the low temperature range (55-75°C as well as high temperature range (150-300 °C for no wind condition only. The experimental set-up mainly consists of spherical cavity receiver which is insulated with glass wool insulation to reduce the heat losses from outside surface. The numerical analysis is carried out by using CFD software and the results are compared with the experimental results and found good agreement. The result shows that the convective loss increases with decrease in cavity inclination angle and decreases with decrease in mean cavity receiver temperature. The maximum losses are obtained at 0° inclination angle and the minimum losses are obtained at 90° inclination angle of cavity due to increase in stagnation zone in to the cavity from 0° to 90° inclination. The Nusselt number correlation is developed for the low temperature range 55-75°C based on the experimental data. The analysis is also carried out to study the effect of wind speed and wind direction on convective heat losses. The convective heat losses are studied for two wind speeds (3 m/s and 5 m/s and four wind directions [α is 0° (Side-on wind, 30°, 60°, and 90° (head-on wind]. It is found that the convective heat losses for both wind speed are higher than the losses obtained by no wind test. The highest heat losses are found for wind direction α is 60° with respect to receiver stand and lowest heat losses are found

  9. The flow distribution in the parallel tubes of the cavity receiver under variable heat flux

    International Nuclear Information System (INIS)

    Hao, Yun; Wang, Yueshe; Hu, Tian

    2016-01-01

    Highlights: • An experimental loop is built to find the flow distribution in the parallel tubes. • With the concentration of heat flux, two-phase flow makes distribution more uneven. • The total flow rate is chosen appropriately for a wider heat flux distribution. • A suitable system pressure is essential for the optimization of flow distribution. - Abstract: As an optical component of tower solar thermal power station, the heliostat mirror reflects sunlight to one point of the heated surface in the solar cavity receiver, called as one-point focusing system. The radiation heat flux concentrated in the cavity receiver is always non-uniform temporally and spatially, which may lead to extremely local over-heat on the receiver evaporation panels. In this paper, an electrical heated evaporating experimental loop, including five parallel vertical tubes, is set up to evaluate the hydrodynamic characteristics of evaporation panels in a solar cavity receiver under various non-uniform heat flux. The influence of the heat flux concentration ratio, total flow rate, and system pressure on the flow distribution of parallel tubes is discussed. It is found that the flow distribution becomes significantly worse with the increase of heat flux and concentration ratio; and as the system pressure decreased, the flow distribution is improved. It is extremely important to obtain these interesting findings for the safe and stable operation of solar cavity receiver, and can also provide valuable references for the design and optimization of operating parameters solar tower power station system.

  10. Wind effects on convective heat loss from a cavity receiver for a parabolic concentrating solar collector

    Energy Technology Data Exchange (ETDEWEB)

    Ma, R.Y. [California State Polytechnic Univ., Pomoma, CA (United States). Dept. of Mechanical Engineering

    1993-09-01

    Tests were performed to determine the convective heat loss characteristics of a cavity receiver for a parabolid dish concentrating solar collector for various tilt angles and wind speeds of 0-24 mph. Natural (no wind) convective heat loss from the receiver is the highest for a horizontal receiver orientation and negligible with the reveler facing straight down. Convection from the receiver is substantially increased by the presence of side-on wind for all receiver tilt angles. For head-on wind, convective heat loss with the receiver facing straight down is approximately the same as that for side-on wind. Overall it was found that for wind speeds of 20--24 mph, convective heat loss from the receiver can be as much as three times that occurring without wind.

  11. Effects of Absorber Emissivity on Thermal Performance of a Solar Cavity Receiver

    Directory of Open Access Journals (Sweden)

    Jiabin Fang

    2014-01-01

    Full Text Available Solar cavity receiver is a key component to realize the light-heat conversion in tower-type solar power system. It usually has an aperture for concentrated sunlight coming in, and the heat loss is unavoidable because of this aperture. Generally, in order to improve the thermal efficiency, a layer of coating having high absorptivity for sunlight would be covered on the surface of the absorber tubes inside the cavity receiver. As a result, it is necessary to investigate the effects of the emissivity of absorber tubes on the thermal performance of the receiver. In the present work, the thermal performances of the receiver with different absorber emissivity were numerically simulated. The results showed that the thermal efficiency increases and the total heat loss decreases with increasing emissivity of absorber tubes. However, the thermal efficiency increases by only 1.6% when the emissivity of tubes varies from 0.2 to 0.8. Therefore, the change of absorber emissivity has slight effect on the thermal performance of the receiver. The reason for variation tendency of performance curves was also carefully analyzed. It was found that the temperature reduction of the cavity walls causes the decrease of the radiative heat loss and the convective heat loss.

  12. Thermodynamic analysis of an organic rankine cycle using a tubular solar cavity receiver

    International Nuclear Information System (INIS)

    Loni, R.; Kasaeian, A.B.; Mahian, O.; Sahin, A.Z.

    2016-01-01

    Highlights: • A non-regenerative Organic Rankine Cycle has been analyzed. • R113, R601, R11, R141b, Ethanol and Methanol were used as the working fluid. • A parabolic dish concentrator with a square prismatic cavity receiver was used. • Thermal efficiency, second law efficiency, and net power output were analyzed. - Abstract: In this study, a non-regenerative Organic Rankine Cycle (ORC) has been thermodynamically analyzed under superheated conditions, constant evaporator pressure of 2.5 MPa, and condenser temperature of 300 K. R113, R601, R11, R141b, Ethanol and Methanol were employed as the working fluid. A parabolic dish concentrator with a square prismatic tubular cavity receiver was used as the heat source of the ORC system. The effects of the tube diameter, the cavity depth, and the solar irradiation on the thermodynamic performance of the selected working fluid were investigated. Some thermodynamic parameters were analyzed in this study. These thermodynamic parameters included the thermal efficiency, second law efficiency, total irreversibility, availability ratio, mass flow rate, and net power output. The results showed that, among the selected working fluids, methanol had the highest thermal efficiency, net power output, second law efficiency, and availability ratio in the range of turbine inlet temperature (TIT) considered. On the other hand, methanol had the smallest total irreversibility in the same range of TIT. The results showed also that mass flow rate and consequently the net power output increased for higher solar irradiation, smaller tube diameter, and for the case of cubical cavity receiver (i.e. cavity depth h equal to the receiver aperture side length a).

  13. Solar power generation by use of Stirling engine and heat loss analysis of its cavity receiver

    Science.gov (United States)

    Hussain, Tassawar

    Since concentrated power generation by Stirling engine has the highest efficiency therefore efficient power generation by concentrated systems using a Stirling engine was a primary motive of this research. A 1 kW Stirling engine was used to generate solar power using a Fresnel lens as a concentrator. Before operating On-Sun test, engine's performance test was conducted by combustion test. Propane gas with air was used to provide input heat to the Stirling Engine and 350W power was generated with 14% efficiency of the engine. Two kinds of receivers were used for On-Sun test, first type was the Inconel tubes with trapped helium gas and the second one was the heat pipe. Heat pipe with sodium as a working fluid is considered the best approach to transfer the uniform heat from the receiver to the helium gas in the heater head of the engine. A Number of On-Sun experiments were performed to generate the power. A minimum 1kW input power was required to generate power from the Stirling engine but it was concluded that the available Fresnel lens was not enough to provide sufficient input to the Stirling engine and hence engine was lagged to generate the solar power. Later on, for a high energy input a Beam Down system was also used to concentrate the solar light on the heater head of the Stirling engine. Beam down solar system in Masdar City UAE, constructed in 2009 is a variation of central receiver plant with cassegrainian optics. Around 1.5kW heat input was achieved from the Beam Down System and it was predicted that the engine receiver at beam down has the significant heat losses of about 900W. These high heat losses were the major hurdles to get the operating temperature (973K) of the heat pipes; hence power could not be generated even during the Beam Down test. Experiments were also performed to find the most suitable Cavity Receiver configuration for maximum solar radiation utilizations by engine receiver. Dimensionless parameter aperture ration (AR=d/D) and aperture

  14. A comparative Thermal Analysis of conventional parabolic receiver tube and Cavity model tube in a Solar Parabolic Concentrator

    Science.gov (United States)

    Arumugam, S.; Ramakrishna, P.; Sangavi, S.

    2018-02-01

    Improvements in heating technology with solar energy is gaining focus, especially solar parabolic collectors. Solar heating in conventional parabolic collectors is done with the help of radiation concentration on receiver tubes. Conventional receiver tubes are open to atmosphere and loose heat by ambient air currents. In order to reduce the convection losses and also to improve the aperture area, we designed a tube with cavity. This study is a comparative performance behaviour of conventional tube and cavity model tube. The performance formulae were derived for the cavity model based on conventional model. Reduction in overall heat loss coefficient was observed for cavity model, though collector heat removal factor and collector efficiency were nearly same for both models. Improvement in efficiency was also observed in the cavity model’s performance. The approach towards the design of a cavity model tube as the receiver tube in solar parabolic collectors gave improved results and proved as a good consideration.

  15. Modeling study on the thermal performance of a modified cavity receiver with glass window and secondary reflector

    International Nuclear Information System (INIS)

    Chang, Huawei; Duan, Chen; Wen, Ke; Liu, Yuting; Xiang, Can; Wan, Zhongmin; He, Sinian; Jing, Changwei; Shu, Shuiming

    2015-01-01

    Highlights: • A modified cavity receiver with glass window and secondary reflector is presented. • Optical and thermal performance of the modified cavity receiver is investigated. • Effects of glass window and secondary reflector are analyzed with comparison study. - Abstract: The development of a cavity receiver for a 1 kW beta type solar Stirling engine is presented in this work. The proposed receiver is composed of an additional quartz glass window and a secondary reflector aiming at improving the thermal performance. Monte-Carlo ray-tracing method is adopted to study the optical property and calculate radiative exchange factors of the solar collector system. The results show that the radiation flux sent to the proposed cavity receiver is 5003 W, and the optical efficiency of this receiver is 70.8%. Numerical simulation is conducted to investigate the thermal performance of this modified receiver. The proposed receiver is also compared with other three simulated receivers combining the presence and absence of the quartz glass window and the secondary reflector. The numerical simulation results show that the modified receiver with both quartz glass window and secondary trumpet reflector outperformed other designs, and its heat loss is reduced about 56% compared to the initial receiver without both quartz glass window and secondary reflector. Hence, the impact factors on the modified receiver radiation and convection heat transfer are well analyzed including temperature, the inner surface orientation and emissivity. The research indicates that the proposed cavity receiver can efficiently reduce the heat loss from cavity and is suitable for Stirling engine applications.

  16. Cavities

    Science.gov (United States)

    ... mother's bacteria from being passed to the child. Treatment of Cavities Fluoride Fillings Root canal or tooth extraction If ... to help the world be well. From developing new therapies that treat and prevent disease to helping people ...

  17. Numerical research of dynamic characteristics in tower solar cavity receiver based on step-change radiation flux

    Science.gov (United States)

    Chen, Zhengwei; Wang, Yueshe; Hao, Yun; Wang, Qizhi

    2013-07-01

    The solar cavity receiver is an important light-energy to thermal-energy convector in the tower solar thermal power plant system. The heat flux in the inner surface of the cavity will show the characteristics of non-continuous step change especially in non-normal and transient weather conditions, which may result in a continuous dynamic variation of the characteristic parameters. Therefore, the research of dynamic characteristics of the receiver plays a very important role in the operation and the control safely in solar cavity receiver system. In this paper, based on the non-continuous step change of radiation flux, a non-linear dynamic model is put forward to obtain the effects of the non-continuous step change radiation flux and step change feed water flow on the receiver performance by sequential modular approach. The subject investigated in our study is a 1MW solar power station constructed in Yanqing County, Beijing. This study has obtained the dynamic responses of the characteristic parameters in the cavity receiver, such as drum pressure, drum water level, main steam flow and main steam enthalpy under step change radiation flux. And the influence law of step-change feed water flow to the dynamic characteristics in the receiver also has been analyzed. The results have a reference value for the safe operation and the control in solar cavity receiver system.

  18. Combining ray tracing and CFD in the thermal analysis of a parabolic dish tubular cavity receiver

    Science.gov (United States)

    Craig, Ken J.; Marsberg, Justin; Meyer, Josua P.

    2016-05-01

    This paper describes the numerical evaluation of a tubular receiver used in a dish Brayton cycle. In previous work considering the use of Computational Fluid Dynamics (CFD) to perform the calculation of the absorbed radiation from the parabolic dish into the cavity as well as the resulting conjugate heat transfer, it was shown that an axi-symmetric model of the dish and receiver absorbing surfaces was useful in reducing the computational cost required for a full 3-D discrete ordinates solution, but concerns remained about its accuracy. To increase the accuracy, the Monte Carlo ray tracer SolTrace is used to perform the calculation of the absorbed radiation profile to be used in the conjugate heat transfer CFD simulation. The paper describes an approach for incorporating a complex geometry like a tubular receiver generated using CFD software into SolTrace. The results illustrate the variation of CFD mesh density that translates into the number of elements in SolTrace as well as the number of rays used in the Monte Carlo approach and their effect on obtaining a resolution-independent solution. The conjugate heat transfer CFD simulation illustrates the effect of applying the SolTrace surface heat flux profile solution as a volumetric heat source to heat up the air inside the tube. Heat losses due to convection and thermal re-radiation are also determined as a function of different tube absorptivities.

  19. Cavities

    Science.gov (United States)

    ... Additional Content Medical News Cavities ˈkav-ət-ē (Dental Caries) By James T. Ubertalli, DMD, Private Practice, Hingham, ... access to dental care, and better treatment for tooth decay and periodontal disease. When teeth are lost, chewing is greatly hindered, and speaking ...

  20. The efficiency of an open-cavity tubular solar receiver for a small-scale solar thermal Brayton cycle

    International Nuclear Information System (INIS)

    Le Roux, W.G.; Bello-Ochende, T.; Meyer, J.P.

    2014-01-01

    Highlights: • Results show efficiencies of a low-cost stainless steel tubular cavity receiver. • Optimum ratio of 0.0035 is found for receiver aperture area to concentrator area. • Smaller receiver tube and higher mass flow rate increase receiver efficiency. • Larger tube and smaller mass flow rate increase second law efficiency. • Large-tube receiver performs better in the small-scale solar thermal Brayton cycle. - Abstract: The first law and second law efficiencies are determined for a stainless steel closed-tube open rectangular cavity solar receiver. It is to be used in a small-scale solar thermal Brayton cycle using a micro-turbine with low compressor pressure ratios. There are many different variables at play to model the air temperature increase of the air running through such a receiver. These variables include concentrator shape, concentrator diameter, concentrator rim angle, concentrator reflectivity, concentrator optical error, solar tracking error, receiver aperture area, receiver material, effect of wind, receiver tube diameter, inlet temperature and mass flow rate through the receiver. All these variables are considered in this paper. The Brayton cycle requires very high receiver surface temperatures in order to be successful. These high temperatures, however, have many disadvantages in terms of heat loss from the receiver, especially radiation heat loss. With the help of ray-tracing software, SolTrace, and receiver modelling techniques, an optimum receiver-to-concentrator-area ratio of A′ ≈ 0.0035 was found for a concentrator with 45° rim angle, 10 mrad optical error and 1° tracking error. A method to determine the temperature profile and net heat transfer rate along the length of the receiver tube is presented. Receiver efficiencies are shown in terms of mass flow rate, receiver tube diameter, pressure drop, maximum receiver surface temperature and inlet temperature of the working fluid. For a 4.8 m diameter parabolic dish, the

  1. Short range micro-power impulse radar with high resolution swept range gate with damped transmit and receive cavities

    Science.gov (United States)

    McEwan, Thomas E.

    1998-01-01

    A radar range finder and hidden object locator is based on ultra-wide band radar with a high resolution swept range gate. The device generates an equivalent time amplitude scan with atypical range of 4 inches to 20 feet, and an analog range resolution as limited by a jitter of on the order of 0.01 inches. A differential sampling receiver is employed to effectively eliminate ringing and other aberrations induced in the receiver by the near proximity of the transmit antenna, so a background subtraction is not needed, simplifying the circuitry while improving performance. Uses of the invention include a replacement of ultrasound devices for fluid level sensing, automotive radar, such as cruise control and parking assistance, hidden object location, such as stud and rebar finding. Also, this technology can be used when positioned over a highway lane to collect vehicle count and speed data for traffic control. Techniques are used to reduce clutter in the receive signal, such as decoupling the receive and transmit cavities by placing a space between them, using conductive or radiative damping elements on the cavities, and using terminating plates on the sides of the openings.

  2. Thermal performance prediction and sensitivity analysis for future deployment of molten salt cavity receiver solar power plants in Algeria

    International Nuclear Information System (INIS)

    Boudaoud, S.; Khellaf, A.; Mohammedi, K.; Behar, O.

    2015-01-01

    Highlights: • Performance of power plant with molten salt cavity receiver is assessed. • A method has been used to optimize the plant solar multiple, capacity factor and LEC. • Comparison of the simulated results to those of PS20 has shown good agreement. • Higher fossil fuel fraction reduces the LEC and increases the capacity factor. • Highland and Sahara regions are suitable for CRS plants deployment. - Abstract: Of all Concentrating Solar Power (CSP) technologies available today, the molten salt solar power plant appears to be the most important option for providing a major share of the clean and renewable electricity needed in the future. In the present paper, a technical and economic analysis for the implementation of a probable molten salt cavity receiver thermal power plant in Algeria has been carried out. In order to do so, we have investigated the effect of solar field size, storage capacity factor, solar radiation intensity, hybridization and power plant capacity on the thermal efficiency and electricity cost of the selected plant. The system advisor model has been used to perform the technical performance and the economic assessment for different locations (coastal, highland and Sahara regions) in Algeria. Taking into account various factors, a method has been applied to optimize the solar multiple and the capacity factor of the plant, to get a trade-off between the incremental investment costs of the heliostat field and the thermal energy storage. The analysis has shown that the use of higher fossil fuel fraction significantly reduces the levelized electricity cost (LEC) and sensibly increases the capacity factor (CF). The present study indicates that hybrid molten salt solar tower power technology is very promising. The CF and the LEC have been found to be respectively of the order of 71% and 0.35 $/kW e . For solar-only power plants, these parameters are respectively about 27% and 0.63 $/kW e . Therefore, hybrid central receiver systems are

  3. Impact of start-up and shut-down losses on the economic benefit of an integrated hybrid solar cavity receiver and combustor

    International Nuclear Information System (INIS)

    Lim, Jin Han; Hu, Eric; Nathan, Graham J.

    2016-01-01

    Highlights: • We present the benefits of integrating a solar cavity receiver and a combustor. • The hybrid solar receiver combustor is compared with its equivalent hybrid. • The start-up losses of the back-up boiler are calculated for a variable resource. • Levelized cost of electricity is reduced by up to 17%. • Fuel consumption is reduced by up to 31%. - Abstract: The impact of avoiding the start-up and shut-down losses of a solar thermal power plant by directly integrating the back-up boiler into a tubular solar-only cavity receiver is studied using a multiple time-step, piecewise-continuous model. A steady-state analytical model of the mass and energy flows through both this device and a solar-only cavity receiver reported previously are incorporated within a model of the solar power generating plant with storage. The performance of the Hybrid Solar Receiver Combustor (HSRC) is compared with an equivalent reference conventional hybrid solar thermal system employing a solar-only cavity receiver and a back-up boiler. The model accounts for start-up and shut-down losses of the boiler, threshold losses of the solar-only cavity receiver and the amount of trace heating required to avoid cooling of the heat transfer fluid. The model is implemented for a 12 month/five year time-series of historical Direct Normal Irradiation (DNI) at 1 h time-steps to account for the variability in the solar resource at four sites spanning Australia and the USA. A method to optimize the size of the heliostat field is also reported, based on the dumped fraction of solar power from the heliostat field. The Levelized Cost of Electricity (LCOE) for the HSRC configuration was estimated to be reduced by up to 17% relative to the equivalent conventional hybrid solar thermal system depending on the cost of the fuel, the storage capacity and the solar resource, while the fuel consumption was estimated to be reduced by some 12–31%.

  4. Free convective heat loss from cavity-type solar furnace; Solar receiver kara no shizen tairyu ni yoru netsusonshitsu

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, I.; Ito, N. [Meiji University, Tokyo (Japan)

    1996-10-27

    Free convective heat loss from solar heat receivers was studied, using three laboratory model receivers (different in depth L and aperture diameter d) heated by electric heaters. Most of the heat produced by heaters was transmitted to the air inside. The cylindrical vessel walls were fully insulated against heat. Heat loss being supposed to result mainly from transfer by free convection, the experiment results were edited by use of Nusselt number Nu and Rayley number Ra. Relations between Nu(D/d){sup m1} and Ra(L/D){sup m2} were plotted in a chart. Here, D is the receiver inner diameter, and m1 and m2 are constants that can be determined by computation. Tests points were provided approximately lineally, irrespective of D, L, or receiver inclination. Air currents were found to produce one or more swirls inside, thanks to the current visualization technique, when the receiver inclination was not sharper than 120{degree} (except 0{degree}). The number of swirls increased as the inner wall temperature rose. This kind of behavior of air currents directly affects the degree of heat loss. 9 refs., 4 figs.

  5. Proposal of a fluid flow layout to improve the heat transfer in the active absorber surface of solar central cavity receivers

    International Nuclear Information System (INIS)

    Montes, M.J.; Rovira, A.; Martínez-Val, J.M.; Ramos, A.

    2012-01-01

    The main objective of concentrated solar power is to increase the thermal energy of a fluid, for the fluid to be used, for example, in a power cycle to generate electricity. Such applications present the requirement of appropriately designing the receiver active absorber surface, as the incident radiation flux can be very high. Besides that, the solar image in the receiver is not uniform, so conventional boilers designs are not well suited for these purposes. That point is particularly critical in solar central receivers systems (CRS), where concentrated solar flux is usually above 500 kW/m 2 , causing thermal and mechanical stress in the absorber panels. This paper analyzes a new thermofluidynamic design of a solar central receiver, which optimizes the heat transfer in the absorber surface. This conceptual receiver presents the following characteristics: the fluid flow pattern is designed according to the radiation flux map symmetry, so more uniform fluid temperatures at the receiver outlet are achieved; the heat transfer irreversibilities are reduced by circulating the fluid from the lower temperature region to the higher temperature region of the absorber surface; the width of each pass is adjusted to the solar flux gradient, to get lower temperature differences between the side tubes of the same pass; and the cooling requirement is ensured by means of adjusting the fluid flow velocity per tube, taking into account the pressure drop. This conceptual scheme has been applied to the particular case of a molten salt single cavity receiver, although the configuration proposed is suitable for other receiver designs and working fluids. - Highlights: ► The solar receiver design proposed optimizes heat transfer in the absorber surface. ► The fluid flow pattern is designed according to the solar flux map symmetry at noon. ► The fluid circulates from the lower to the higher temperature regions. ► The width of each pass is adjusted to the solar flux gradient.

  6. Dental cavities

    Science.gov (United States)

    ... acids in plaque damage the enamel covering your teeth. It also creates holes in the tooth called cavities. Cavities usually do not hurt, unless they grow very large and affect nerves or cause a tooth fracture. An untreated cavity can lead to an infection ...

  7. Cavity-cavity conditional logic

    Science.gov (United States)

    Rosenblum, Serge; Gao, Yvonne Y.; Reinhold, Philip; Wang, Chen; Axline, Christopher; Frunzio, Luigi; Girvin, Steven M.; Jiang, Liang; Mirrahimi, Mazyar; Devoret, Michel H.; Schoelkopf, Robert J.

    In a superconducting circuit architecture, the highest coherence times are typically offered by 3D cavities. Moreover, these cavities offer a hardware-efficient way of redundantly encoding quantum information. While single-qubit control on a cavity has already been demonstrated, there is a need for a universal two-qubit gate between such cavities. In this talk, we demonstrate a cavity-cavity gate by parametric pumping on a fixed-frequency transmon interacting with the two cavities. Every gate application lowers the state fidelity by only 1%, while maintaining an entangling rate on-off ratio of 29dB. Additionally, we show that the gate is applicable not only to qubits consisting of single photons, but also to more complex encodings. These results illustrate the usefulness of cavities beyond the mere storage of quantum information, and pave the way towards gates between error-corrected logical qubits.

  8. Cavity types

    CERN Document Server

    Gerigk, Frank

    2011-01-01

    In the field of particle accelerators the most common use of RF cavities is to increase the particle velocity of traversing particles. This feature makes them one of the core ingredients of every accelerator, and in the case of linear accelerators they are even the dominant machine component. Since there are many different types of accelerator, RF cavities have been optimized for different purposes and with different abilities, e.g., cavities with fixed or variable RF frequency, cavities for short or long pulses/CW operation, superconducting and normal-conducting cavities. This lecture starts with a brief historical introduction and an explanation on how to get from Maxwell's equations to a simple cavity. Then, cavities will be classified by the type of mode that is employed for acceleration, and an explanation is given as to why certain modes are used in particular cavity types. The lecture will close with a comparison of normal versus superconducting cavities and a few words on the actual power consumption ...

  9. Digital Cavity Resonance Monitor, alternative method of measuring cavity microphonics

    International Nuclear Information System (INIS)

    Tomasz Plawski; G. Davis; Hai Dong; J. Hovater; John Musson; Thomas Powers

    2005-01-01

    As is well known, mechanical vibration or microphonics in a cryomodule causes the cavity resonance frequency to change at the vibration frequency. One way to measure the cavity microphonics is to drive the cavity with a Phase Locked Loop. Measurement of the instantaneous frequency or PLL error signal provides information about the cavity microphonic frequencies. Although the PLL error signal is available directly, precision frequency measurements require additional instrumentation, a Cavity Resonance Monitor (CRM). The analog version of such a device has been successfully used for several cavity tests [1]. In this paper we present a prototype of a Digital Cavity Resonance Monitor designed and built in the last year. The hardware of this instrument consists of an RF downconverter, digital quadrature demodulator and digital processor motherboard (Altera FPGA). The motherboard processes received data and computes frequency changes with a resolution of 0.2 Hz, with a 3 kHz output bandwidth

  10. accelerating cavity

    CERN Multimedia

    On the inside of the cavity there is a layer of niobium. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment.

  11. radiofrequency cavity

    CERN Multimedia

    1988-01-01

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  12. Cavity Optomechanics

    OpenAIRE

    Kippenberg, T. J.; Vahala, K. J.

    2007-01-01

    The coupling of mechanical and optical degrees of freedom via radiation pressure has been a subject of early research in the context of gravitational wave detection. Recent experimental advances have allowed studying for the first time the modifications of mechanical dynamics provided by radiation pressure. This paper reviews the consequences of back-action of light confined in whispering-gallery dielectric micro-cavities, and presents a unified treatment of its two manifestations: notably th...

  13. Call for Papers: Cavity QED

    Science.gov (United States)

    Lange, W.; Gerard, J.-M.

    2003-06-01

    Cavity QED interactions of light and matter have been investigated in a wide range of systems covering the spectrum from microwaves to optical frequencies, using media as diverse as single atoms and semiconductors. Impressive progress has been achieved technologically as well as conceptually. This topical issue of Journal of Optics B: Quantum and Semiclassical Optics is intended to provide a comprehensive account of the current state of the art of cavity QED by uniting contributions from researchers active across this field. As Guest Editors of this topical issue, we invite manuscripts on current theoretical and experimental work on any aspects of cavity QED. The topics to be covered will include, but are not limited to: bulletCavity QED in optical microcavities bulletSemiconductor cavity QED bulletQuantum dot cavity QED bulletRydberg atoms in microwave cavities bulletPhotonic crystal cavity QED bulletMicrosphere resonators bulletMicrolasers and micromasers bulletMicrodroplets bulletDielectric cavity QED bulletCavity QED-based quantum information processing bulletQuantum state engineering in cavities The DEADLINE for submission of contributions is 31 July 2003 to allow the topical issue to appear in about February 2004. All papers will be peer-reviewed in accordance with the normal refereeing procedures and standards of Journal of Optics B: Quantum and Semiclassical Optics. Advice on publishing your work in the journal may be found at www.iop.org/journals/authors/jopb. Submissions should ideally be in either standard LaTeX form or Microsoft Word. There are no page charges for publication. In addition to the usual 50 free reprints, the corresponding author of each paper published will receive a complimentary copy of the topical issue. Contributions to the topical issue should if possible be submitted electronically at www.iop.org/journals/jopb. or by e-mail to jopb@iop.org. Authors unable to submit online or by e-mail may send hard copy contributions (enclosing the

  14. Status of the ILC Crab Cavity Development

    Energy Technology Data Exchange (ETDEWEB)

    Burt, G.; Dexter, A.; /Cockcroft Inst. Accel. Sci. Tech.; Beard, C.; Goudket, P.; McIntosh, P.; /Daresbury; Bellantoni, L.; /Fermilab; Grimm, T.; Li, Z.; Xiao, L.; /SLAC

    2011-10-20

    The International Linear Collider (ILC) will require two dipole cavities to 'crab' the electron and positron bunches prior to their collision. It is proposed to use two 9 cell SCRF dipole cavities operating at a frequency of 3.9 GHz, with a transverse gradient of 3.8MV/m in order to provide the required transverse kick. Extensive numerical modelling of this cavity and its couplers has been performed. Aluminium prototypes have been manufactured and tested to measure the RF properties of the cavity and couplers. In addition single cell niobium prototypes have been manufactured and tested in a vertical cryostat. The International Collider (ILC) [1] collides bunches of electrons and positrons at a crossing angle of 14 mrad. The angle between these bunches causes a loss in luminosity due to geometric effects [2]. The luminosity lost from this geometric effect can be recovered by rotating the bunches into alignment prior to collision. One possible method of rotating the bunches is to use a crab cavity [3]. A crab cavity is a transverse defecting cavity, where the phase of the cavity is such that the head and tail of the bunch receive equal and opposite kicks. As the bunches are only 500 nm wide in the horizontal plane, the cavity phase must be strictly controlled to avoid the bunch centre being deflected too much. In order to keep the phase stability within the required limits it is required that the cavity be superconducting to avoid thermal effects in both the cavity and its RF source. At the location of the crab cavity in the ILC there is only 23 cm separation between the centre of the cavity and the extraction line, hence the cavity must be small enough to fit in this space. This, along with the difficulty of making high frequency SRF components, set the frequency of the cavity to 3.9 GHz.

  15. Solar thermal energy receiver

    Science.gov (United States)

    Baker, Karl W. (Inventor); Dustin, Miles O. (Inventor)

    1992-01-01

    A plurality of heat pipes in a shell receive concentrated solar energy and transfer the energy to a heat activated system. To provide for even distribution of the energy despite uneven impingement of solar energy on the heat pipes, absence of solar energy at times, or failure of one or more of the heat pipes, energy storage means are disposed on the heat pipes which extend through a heat pipe thermal coupling means into the heat activated device. To enhance energy transfer to the heat activated device, the heat pipe coupling cavity means may be provided with extensions into the device. For use with a Stirling engine having passages for working gas, heat transfer members may be positioned to contact the gas and the heat pipes. The shell may be divided into sections by transverse walls. To prevent cavity working fluid from collecting in the extensions, a porous body is positioned in the cavity.

  16. Segmented trapped vortex cavity

    Science.gov (United States)

    Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

    2010-01-01

    An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

  17. Analysis of mechanical fabrication experience with CEBAF's production SRF cavities

    International Nuclear Information System (INIS)

    Mammosser, J.; Kneisel, P.; Benesch, J.

    1993-06-01

    CEBAF has received a total of 360 five-cell niobium cavities, the largest group of industrially fabricated superconducting cavities so far. An extensive data base exists on the fabrication, surface treatment, assembly and cavity performance parameters. Analysis of the mechanical features of the cavities includes the following: the spread in fabrication tolerances of the cells derived from field profiles of the ''as fabricated'' cavities and the ''as fabricated'' external Q-values of the fundamental power coupler compared to dimensional deviations. A comparison is made of the pressure sensitivity of cavities made of materials from different manufacturers between 760 torr (4.2 K) and 23 torr (2 K)

  18. Books Received

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. Books Received. Articles in Resonance – Journal of Science Education. Volume 1 Issue 1 January 1996 pp 118-118 Books Received. Books Received · More Details Fulltext PDF. Volume 1 Issue 2 February 1996 pp 120-120 Books Received. Books Received.

  19. The LHC superconducting cavities

    CERN Document Server

    Boussard, Daniel; Häbel, E; Kindermann, H P; Losito, R; Marque, S; Rödel, V; Stirbet, M

    1999-01-01

    The LHC RF system, which must handle high intensity (0.5 A d.c.) beams, makes use of superconducting single-cell cavities, best suited to minimizing the effects of periodic transient beam loading. There will be eight cavities per beam, each capable of delivering 2 MV (5 MV/m accelerating field) at 400 MHz. The cavities themselves are now being manufactured by industry, using niobium-on-copper technology which gives full satisfaction at LEP. A cavity unit includes a helium tank (4.5 K operating temperature) built around a cavity cell, RF and HOM couplers and a mechanical tuner, all housed in a modular cryostat. Four-unit modules are ultimately foreseen for the LHC (two per beam), while at present a prototype version with two complete units is being extensively tested. In addition to a detailed description of the cavity and its ancillary equipment, the first test results of the prototype will be reported.

  20. LEP copper accelerating cavities

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    These copper cavities were used to generate the radio frequency electric field that was used to accelerate electrons and positrons around the 27-km Large Electron-Positron (LEP) collider at CERN, which ran from 1989 to 2000. The copper cavities were gradually replaced from 1996 with new superconducting cavities allowing the collision energy to rise from 90 GeV to 200 GeV by mid-1999.

  1. Superconducting cavities for LEP

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Above: a 350 MHz superconducting accelerating cavity in niobium of the type envisaged for accelerating electrons and positrons in later phases of LEP. Below: a small 1 GHz cavity used for investigating the surface problems of superconducting niobium. Albert Insomby stays on the right. See Annual Report 1983 p. 51.

  2. SPS RF Cavity

    CERN Multimedia

    1975-01-01

    The picture shows one of the two initially installed cavities. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also gradually increased: by end 1980 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412017X, 7411048X, 7505074.

  3. SPS RF Accelerating Cavity

    CERN Multimedia

    1979-01-01

    This picture shows one of the 2 new cavities installed in 1978-1979. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also increased: to the first 2 MW plant a second 2 MW plant was added and by end 1979 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412016X, 7412017X, 7411048X

  4. Superconducting TESLA cavities

    Directory of Open Access Journals (Sweden)

    B. Aune

    2000-09-01

    Full Text Available The conceptional design of the proposed linear electron-positron collider TESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with an accelerating gradient of E_{acc}≥25 MV/m at a quality factor Q_{0}≥5×10^{9}. The design goal for the cavities of the TESLA Test Facility (TTF linac was set to the more moderate value of E_{acc}≥15 MV/m. In a first series of 27 industrially produced TTF cavities the average gradient at Q_{0}=5×10^{9} was measured to be 20.1±6.2 MV/m, excluding a few cavities suffering from serious fabrication or material defects. In the second production of 24 TTF cavities, additional quality control measures were introduced, in particular, an eddy-current scan to eliminate niobium sheets with foreign material inclusions and stringent prescriptions for carrying out the electron-beam welds. The average gradient of these cavities at Q_{0}=5×10^{9} amounts to 25.0±3.2 MV/m with the exception of one cavity suffering from a weld defect. Hence only a moderate improvement in production and preparation techniques will be needed to meet the ambitious TESLA goal with an adequate safety margin. In this paper we present a detailed description of the design, fabrication, and preparation of the TESLA Test Facility cavities and their associated components and report on cavity performance in test cryostats and with electron beam in the TTF linac. The ongoing research and development towards higher gradients is briefly addressed.

  5. Hydroforming of elliptical cavities

    Directory of Open Access Journals (Sweden)

    W. Singer

    2015-02-01

    Full Text Available Activities of the past several years in developing the technique of forming seamless (weldless cavity cells by hydroforming are summarized. An overview of the technique developed at DESY for the fabrication of single cells and multicells of the TESLA cavity shape is given and the major rf results are presented. The forming is performed by expanding a seamless tube with internal water pressure while simultaneously swaging it axially. Prior to the expansion the tube is necked at the iris area and at the ends. Tube radii and axial displacements are computer controlled during the forming process in accordance with results of finite element method simulations for necking and expansion using the experimentally obtained strain-stress relationship of tube material. In cooperation with industry different methods of niobium seamless tube production have been explored. The most appropriate and successful method is a combination of spinning or deep drawing with flow forming. Several single-cell niobium cavities of the 1.3 GHz TESLA shape were produced by hydroforming. They reached accelerating gradients E_{acc} up to 35  MV/m after buffered chemical polishing (BCP and up to 42  MV/m after electropolishing (EP. More recent work concentrated on fabrication and testing of multicell and nine-cell cavities. Several seamless two- and three-cell units were explored. Accelerating gradients E_{acc} of 30–35  MV/m were measured after BCP and E_{acc} up to 40  MV/m were reached after EP. Nine-cell niobium cavities combining three three-cell units were completed at the company E. Zanon. These cavities reached accelerating gradients of E_{acc}=30–35  MV/m. One cavity is successfully integrated in an XFEL cryomodule and is used in the operation of the FLASH linear accelerator at DESY. Additionally the fabrication of bimetallic single-cell and multicell NbCu cavities by hydroforming was successfully developed. Several NbCu clad single-cell and

  6. Multicolor cavity soliton.

    Science.gov (United States)

    Luo, Rui; Liang, Hanxiao; Lin, Qiang

    2016-07-25

    We show a new class of complex solitary wave that exists in a nonlinear optical cavity with appropriate dispersion characteristics. The cavity soliton consists of multiple soliton-like spectro-temporal components that exhibit distinctive colors but coincide in time and share a common phase, formed together via strong inter-soliton four-wave mixing and Cherenkov radiation. The multicolor cavity soliton shows intriguing spectral locking characteristics and remarkable capability of spectrum management to tailor soliton frequencies, which would be very useful for versatile generation and manipulation of multi-octave spanning phase-locked Kerr frequency combs, with great potential for applications in frequency metrology, optical frequency synthesis, and spectroscopy.

  7. Cavity-enhanced spectroscopies

    CERN Document Server

    van Zee, Roger

    2003-01-01

    ""Cavity-Enhanced Spectroscopy"" discusses the use of optical resonators and lasers to make sensitive spectroscopic measurements. This volume is written by the researcchers who pioneered these methods. The book reviews both the theory and practice behind these spectroscopic tools and discusses the scientific discoveries uncovered by these techniques. It begins with a chapter on the use of optical resonators for frequency stabilization of lasers, which is followed by in-depth chapters discussing cavity ring-down spectroscopy, frequency-modulated, cavity-enhanced spectroscopy, intracavity spectr

  8. Tuned optical cavity magnetometer

    Science.gov (United States)

    Okandan, Murat; Schwindt, Peter

    2010-11-02

    An atomic magnetometer is disclosed which utilizes an optical cavity formed from a grating and a mirror, with a vapor cell containing an alkali metal vapor located inside the optical cavity. Lasers are used to magnetically polarize the alkali metal vapor and to probe the vapor and generate a diffracted laser beam which can be used to sense a magnetic field. Electrostatic actuators can be used in the magnetometer for positioning of the mirror, or for modulation thereof. Another optical cavity can also be formed from the mirror and a second grating for sensing, adjusting, or stabilizing the position of the mirror.

  9. Heat loss from an open cavity

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, C.G. [California State Polytechnic Univ., Pomona, CA (United States). Coll. of Engineering

    1995-12-01

    Cavity type receivers are used extensively in concentrating solar thermal energy collecting systems. The Solar Total Energy Project (STEP) in Shenandoah, Georgia is a large scale field test for the collection of solar thermal energy. The STEP experiment consists of a large field array of solar collectors used to supplement the process steam, cooling and other electrical power requirements of an adjacent knitwear manufacturing facility. The purpose of the tests, conducted for this study, was to isolate and quantify the radiative, conductive, and convective components of total heat loss, and to determine the effects of operating temperature, receiver angle, and aperture size on cavity heat loss. An analytical model for radiative heat loss was developed and compared with two other methods used to determine radiative heat loss. A proposed convective heat loss correlation, including effects of aperture size, receiver operating temperature, and receiver angle is presented. The resulting data is a source to evaluate the STEP measurements.

  10. accelerating cavity from LEP

    CERN Multimedia

    This is an accelerating cavity from LEP, with a layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities are now used in LEP to double the energy of the particle beams.

  11. SPS accelerating cavity

    CERN Multimedia

    CERN PhotoLab

    1976-01-01

    The SPS started up with 2 accelerating cavities (each consisting of 5 tank sections) in LSS3. They have a 200 MHz travelling wave structure (see 7411032 and 7802190) and 750 kW of power is fed to each of the cavities from a 1 MW tetrode power amplifier, located in a surface building above, via a coaxial transmission line. Clemens Zettler, builder of the SPS RF system, is standing at the side of one of the cavities. In 1978 and 1979 another 2 cavities were added and entered service in 1980. These were part of the intensity improvement programme and served well for the new role of the SPS as proton-antiproton collider. See also 7411032, 8011289, 8104138, 8302397.

  12. Hybrid vertical cavity laser

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2010-01-01

    A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide.......A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide....

  13. The Superconducting TESLA Cavities

    CERN Document Server

    Aune, B.; Bloess, D.; Bonin, B.; Bosotti, A.; Champion, M.; Crawford, C.; Deppe, G.; Dwersteg, B.; Edwards, D.A.; Edwards, H.T.; Ferrario, M.; Fouaidy, M.; Gall, P-D.; Gamp, A.; Gössel, A.; Graber, J.; Hubert, D.; Hüning, M.; Juillard, M.; Junquera, T.; Kaiser, H.; Kreps, G.; Kuchnir, M.; Lange, R.; Leenen, M.; Liepe, M.; Lilje, L.; Matheisen, A.; Möller, W-D.; Mosnier, A.; Padamsee, H.; Pagani, C.; Pekeler, M.; Peters, H-B.; Peters, O.; Proch, D.; Rehlich, K.; Reschke, D.; Safa, H.; Schilcher, T.; Schmüser, P.; Sekutowicz, J.; Simrock, S.; Singer, W.; Tigner, M.; Trines, D.; Twarowski, K.; Weichert, G.; Weisend, J.; Wojtkiewicz, J.; Wolff, S.; Zapfe, K.

    2000-01-01

    The conceptional design of the proposed linear electron-positron colliderTESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with anaccelerating gradient of Eacc >= 25 MV/m at a quality factor Q0 > 5E+9. Thedesign goal for the cavities of the TESLA Test Facility (TTF) linac was set tothe more moderate value of Eacc >= 15 MV/m. In a first series of 27industrially produced TTF cavities the average gradient at Q0 = 5E+9 wasmeasured to be 20.1 +- 6.2 MV/m, excluding a few cavities suffering fromserious fabrication or material defects. In the second production of 24 TTFcavities additional quality control measures were introduced, in particular aneddy-current scan to eliminate niobium sheets with foreign material inclusionsand stringent prescriptions for carrying out the electron-beam welds. Theaverage gradient of these cavities at Q0 = 5E+9 amounts to 25.0 +- 3.2 MV/mwith the exception of one cavity suffering from a weld defect. Hence only amoderate improvement in production and preparation technique...

  14. Books Received

    Indian Academy of Sciences (India)

    Books Received. Challenge and Thrill of Pre-College. Mathematics. V Krishnamurthy et al. New Age International. 1996, Rs.220. Mathematics for Science. S M Uppal and H M Humphreys. New Age International. 1996, Rs.17S. Physics for Engineers. M R Srinivasan. New Age Publications. 1996. Statement about ownership ...

  15. Large Grain Niobium Cavity R&D in Asia and the Future

    Energy Technology Data Exchange (ETDEWEB)

    Saito, K; Furuta, F; Saeki, T; Inoue, H; Shim, J; Ahn, J; Kim, E S; Xu, Q; Zong, Z; Gao, J; Kneisel, P; Myneni, G R

    2007-09-01

    The status of the large grain niobium cavity R&D in Asia and the future scope are presented. Recently KEK has received CBMM and NingXia large grain niobium sheets through collaborations. KEK has fabricated 1.3 GHz single cell cavities using these materials and measured the cavity performance. Those results are presented in this paper.

  16. Materials for superconducting cavities

    International Nuclear Information System (INIS)

    Bonin, B.

    1996-01-01

    The ideal material for superconducting cavities should exhibit a high critical temperature, a high critical field, and, above all, a low surface resistance. Unfortunately, these requirements can be conflicting and a compromise has to be found. To date, most superconducting cavities for accelerators are made of niobium. The reasons for this choice are discussed. Thin films of other materials such as NbN, Nb 3 Sn, or even YBCO compounds can also be envisaged and are presently investigated in various laboratories. It is shown that their success will depend critically on the crystalline perfection of these films. (author)

  17. Experimental investigation of cavity flows

    Energy Technology Data Exchange (ETDEWEB)

    Loeland, Tore

    1998-12-31

    This thesis uses LDV (Laser Doppler Velocimetry), PIV (Particle Image Velocimetry) and Laser Sheet flow Visualisation to study flow inside three different cavity configurations. For sloping cavities, the vortex structure inside the cavities is found to depend upon the flow direction past the cavity. The shape of the downstream corner is a key factor in destroying the boundary layer flow entering the cavity. The experimental results agree well with numerical simulations of the same geometrical configurations. The results of the investigations are used to find the influence of the cavity flow on the accuracy of the ultrasonic flowmeter. A method to compensate for the cavity velocities is suggested. It is found that the relative deviation caused by the cavity velocities depend linearly on the pipe flow. It appears that the flow inside the cavities should not be neglected as done in the draft for the ISO technical report on ultrasonic flowmeters. 58 refs., 147 figs., 2 tabs.

  18. Superconducting elliptical cavities

    CERN Document Server

    Sekutowicz, J K

    2011-01-01

    We give a brief overview of the history, state of the art, and future for elliptical superconducting cavities. Principles of the cell shape optimization, criteria for multi-cell structures design, HOM damping schemes and other features are discussed along with examples of superconducting structures for various applications.

  19. LEP superconducting cavity

    CERN Multimedia

    1995-01-01

    Engineers work in a clean room on one of the superconducting cavities for the upgrade to the LEP accelerator, known as LEP-2. The use of superconductors allow higher electric fields to be produced so that higher beam energies can be reached.

  20. Additive Manufactured Superconducting Cavities

    Science.gov (United States)

    Holland, Eric; Rosen, Yaniv; Woolleet, Nathan; Materise, Nicholas; Voisin, Thomas; Wang, Morris; Mireles, Jorge; Carosi, Gianpaolo; Dubois, Jonathan

    Superconducting radio frequency cavities provide an ultra-low dissipative environment, which has enabled fundamental investigations in quantum mechanics, materials properties, and the search for new particles in and beyond the standard model. However, resonator designs are constrained by limitations in conventional machining techniques. For example, current through a seam is a limiting factor in performance for many waveguide cavities. Development of highly reproducible methods for metallic parts through additive manufacturing, referred to colloquially as 3D printing\\x9D, opens the possibility for novel cavity designs which cannot be implemented through conventional methods. We present preliminary investigations of superconducting cavities made through a selective laser melting process, which compacts a granular powder via a high-power laser according to a digitally defined geometry. Initial work suggests that assuming a loss model and numerically optimizing a geometry to minimize dissipation results in modest improvements in device performance. Furthermore, a subset of titanium alloys, particularly, a titanium, aluminum, vanadium alloy (Ti - 6Al - 4V) exhibits properties indicative of a high kinetic inductance material. This work is supported by LDRD 16-SI-004.

  1. Niobium superconducting cavity

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    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.

  2. What's a Cavity?

    Science.gov (United States)

    ... and deeper over time. Cavities are also called dental caries (say: KARE-eez), and if you have a ... made up mostly of the germs that cause tooth decay. The bacteria in your mouth make acids and when plaque clings to your teeth, the acids can eat away at the outermost ...

  3. Filling a Conical Cavity

    Science.gov (United States)

    Nye, Kyle; Eslam-Panah, Azar

    2016-11-01

    Root canal treatment involves the removal of infected tissue inside the tooth's canal system and filling the space with a dense sealing agent to prevent further infection. A good root canal treatment happens when the canals are filled homogeneously and tightly down to the root apex. Such a tooth is able to provide valuable service for an entire lifetime. However, there are some examples of poorly performed root canals where the anterior and posterior routes are not filled completely. Small packets of air can be trapped in narrow access cavities when restoring with resin composites. Such teeth can cause trouble even after many years and lead the conditions like acute bone infection or abscesses. In this study, the filling of dead-end conical cavities with various liquids is reported. The first case studies included conical cavity models with different angles and lengths to visualize the filling process. In this investigation, the rate and completeness at which a variety of liquids fill the cavity were observed to find ideal conditions for the process. Then, a 3D printed model of the scaled representation of a molar with prepared post spaces was used to simulate the root canal treatment. The results of this study can be used to gain a better understanding of the restoration for endodontically treated teeth.

  4. Changeability of Oral Cavity Environment

    OpenAIRE

    Surdacka, Anna; Strzyka?a, Krystyna; Rydzewska, Anna

    2007-01-01

    Objectives In dentistry, the results of in vivo studies on drugs, dental fillings or prostheses are routinely evaluated based on selected oral cavity environment parameters at specific time points. Such evaluation may be confounded by ongoing changes in the oral cavity environment induced by diet, drug use, stress and other factors. The study aimed to confirm oral cavity environment changeability. Methods 24 healthy individuals aged 20?30 had their oral cavity environment prepared by having p...

  5. Optimization of photonic crystal cavities

    DEFF Research Database (Denmark)

    Wang, Fengwen; Sigmund, Ole

    2017-01-01

    We present optimization of photonic crystal cavities. The optimization problem is formulated to maximize the Purcell factor of a photonic crystal cavity. Both topology optimization and air-hole-based shape optimization are utilized for the design process. Numerical results demonstrate...... that the Purcell factor of the photonic crystal cavity can be significantly improved through optimization....

  6. Single-cavity SLED device

    International Nuclear Information System (INIS)

    Lippmann, B.A.

    1984-09-01

    The conventional SLED device used at SLAC requires two cavities. However, the same effect can be obtained with a single cavity; the theory and operation of the device is the same, only the hardware is changed. The single-cavity device is described here

  7. Hollow waveguide cavity ringdown spectroscopy

    Science.gov (United States)

    Dreyer, Chris (Inventor); Mungas, Greg S. (Inventor)

    2012-01-01

    Laser light is confined in a hollow waveguide between two highly reflective mirrors. This waveguide cavity is used to conduct Cavity Ringdown Absorption Spectroscopy of loss mechanisms in the cavity including absorption or scattering by gases, liquid, solids, and/or optical elements.

  8. Benchmarking Microwave Cavity Dark Matter Searches using a Radioactive Source

    CERN Multimedia

    Caspers, F

    2014-01-01

    A radioactive source is proposed as a calibration device to verify the sensitivity of a microwave dark matter search experiment. The interaction of e.g., electrons travelling in an arbitrary direction and velocity through an electromagnetically “empty” microwave cavity can be calculated numerically. We give an estimation of the energy deposited by a charged particle into a particular mode. Numerical examples are given for beta emitters and two particular cases: interaction with a field free cavity and interaction with a cavity which already contains an electromagnetic field. Each particle delivers a certain amount of energy related to the modal R/Q value of the cavity. The transferred energy is a function of the particles trajectory and its velocity. It results in a resonant response of the cavity, which can be observed using a sensitive microwave receiver, provided that the deposited energy is significantly above the single photon threshold.

  9. Colloquium: cavity optomechanics

    CERN Multimedia

    2011-01-01

    Monday 14 November 2011, 17:00 Ecole de Physique, Auditoire Stueckelberg Université de Genève Cavity optomechanics: controlling micro mechanical oscillators with laser light Prof. Tobias Kippenberg EPFL, Lausanne Laser light can be used to cool and to control trapped ions, atoms and molecules at the quantum level. This has lead to spectacular advances such as the most precise atomic clocks. An outstanding frontier is the control with lasers of nano- and micro-mechancial systems. Recent advances in cavity optomechanics have allowed such elementary control for the first time, enabling mechanical systems to be ground state cooled leading to readout with quantum limited sensitivity and permitting to explore new device concepts resulting from radiation pressure.  

  10. Design and Performance of the LCLS Cavity BPM System

    Energy Technology Data Exchange (ETDEWEB)

    Lill, R.M.; Morrison, L.H.; Norum, W.E.; Sereno, N.; Waldschmidt, G.J.; Walters, D.R.; /Argonne; Smith, S.; Straumann, T.; /SLAC

    2008-01-23

    In this paper we present the design of the beam position monitor (BPM) system for the LCLS undulator, which features a high-resolution X-band cavity BPM. Each BPM has a TM{sub 010} monopole reference cavity and a TM{sub 110} dipole cavity designed to operate at a center frequency of 11.384 GHz. The signal processing electronics features a low noise single-stage three-channel heterodyne receiver that has selectable gain and a phase locking local oscillator. We will discuss the system specifications, design, and prototype test results.

  11. Design and performance of the LCLS cavity BPM system.

    Energy Technology Data Exchange (ETDEWEB)

    Lill, R.; Norum, E.; Morrison, L.; Sereno, N.; Waldschmidt, G.; Walters, D.; Smith, S.; Straumann, T.; SLAC

    2008-01-01

    In this paper we present the design of the beam position monitor (BPM) system for the LCLS undulator, which features a high-resolution X-band cavity BPM. Each BPM has a TM{sub 010} monopole reference cavity and a TM{sub 110} dipole cavity designed to operate at a center frequency of 11.384 GHz. The signal processing electronics features a low- noise single-stage three-channel heterodyne receiver that has selectable gain and a phase locking local oscillator. We will discuss the system specifications, design, and prototype test results.

  12. Design and Performance of the LCLS Cavity BPM System

    International Nuclear Information System (INIS)

    Lill, R.M.; Morrison, L.H.; Norum, W.E.; Sereno, N.; Waldschmidt, G.J.; Walters, D.R.; Argonne; Smith, S.; Straumann, T.

    2008-01-01

    In this paper we present the design of the beam position monitor (BPM) system for the LCLS undulator, which features a high-resolution X-band cavity BPM. Each BPM has a TM 010 monopole reference cavity and a TM 110 dipole cavity designed to operate at a center frequency of 11.384 GHz. The signal processing electronics features a low noise single-stage three-channel heterodyne receiver that has selectable gain and a phase locking local oscillator. We will discuss the system specifications, design, and prototype test results

  13. Design and performance of the LCLS cavity BPM system

    International Nuclear Information System (INIS)

    Lill, R.; Norum, E.; Morrison, L.; Sereno, N.; Waldschmidt, G.; Walters, D.; Smith, S.; Straumann, T.

    2008-01-01

    In this paper we present the design of the beam position monitor (BPM) system for the LCLS undulator, which features a high-resolution X-band cavity BPM. Each BPM has a TM 010 monopole reference cavity and a TM 110 dipole cavity designed to operate at a center frequency of 11.384 GHz. The signal processing electronics features a low- noise single-stage three-channel heterodyne receiver that has selectable gain and a phase locking local oscillator. We will discuss the system specifications, design, and prototype test results.

  14. Selective Transfer of Superposition of Coherent States by Exploiting a Cavity QED System

    Science.gov (United States)

    Behzadi, N.; Rudsary, S. Kazemi

    2015-05-01

    We propose a scheme on the basis of a N + 2 identical single-mode coupled-cavity QED system for selective transfer of a qubit constructed from superposition of standard coherent states. The cavities arranged in such way that the intermediate or channel cavity is connected uniformly to the sender and N receiver cavities. We consider N different ternary sets of identical QDs whose QDs have been distributed in the sender, channel and one of the receiver cavities respectively. We demonstrate a situation in which the dynamics of the system is confined selectively in a sub sector belongs to one of the ternary set of QDs. This selective dynamics is able to transfer the coherent state-constructed qubit (CSCQ) from the sender party to the desired receiver one reliably. Also, we illustrate that the scheme is optimally robust due to dissipations arises from photon losses in the cavities.

  15. ISR RF cavities

    CERN Multimedia

    1983-01-01

    In each ISR ring the radiofrequency cavities were installed in one 9 m long straight section. The RF system of the ISR had the main purpose to stack buckets of particles (most of the time protons)coming from the CPS and also to accelerate the stacked beam. The installed RF power per ring was 18 kW giving a peak accelerating voltage of 20 kV. The system had a very fine regulation feature allowing to lower the voltage down to 75 V in a smooth and well controlled fashion.

  16. Cavity Pull Rod: Device to Promote Single Crystal Growth from the Melt

    Science.gov (United States)

    Goldsby, Jon (Inventor)

    2017-01-01

    A pull rod for use in producing a single crystal from a molten alloy is provided that includes an elongated rod having a first end and a second end, a first cavity defined at the first end and a second cavity defined at the first end and in communication with the first cavity. The first cavity receives the molten alloy and the second cavity vents a gas from the molten alloy to thereby template a single crystal when the pull rod is dipped into and extracted from the molten alloy.

  17. Bioengineering in the oral cavity: our experience

    Directory of Open Access Journals (Sweden)

    Catalfamo L

    2013-10-01

    Full Text Available L Catalfamo,1 E Belli,2 C Nava,1 E Mici,1 A Calvo,1 B D'Alessandro,1 FS De Ponte1 1Unit of Maxillofacial Surgery, University of Messina, Azienda Ospedaliera Universitaria, Policlinico G Martino, Messina, Italy; 2Unit of Maxillofacial Surgery, University Rome Sapienza, Azienda Ospedaliera Sant Andrea, Rome, Italy Background: To date, there are no studies reported in the literature on the possible use of bovine collagen, oxidized regenerated cellulose, or synthetic hyaluronic acid medications in the oral cavity. The aim of this paper is to report the use of bovine collagen, oxidized regenerated cellulose, and synthetic hyaluronic acid medications to improve wound healing in the oral cavity by stimulating granulomatous tissue. Methods: From 2007 to 2011, 80 patients (median age 67 years suffering from oral mucosal lesions participated in this double-blind study. The patients were divided into two groups, each consisting of 40 patients. One group received conventional medications, while the other group of patients were treated with the advanced medications. Results: Advanced medications allowed re-epithelialization of the wound margin in 2–20 days, whereas patients receiving conventional medication showed a median healing duration of 45 days. Conclusion: The results of this study demonstrate that treating oral mucosal wounds with advanced medication has an advantage with regard to wound healing time, allowing patients to have a rapid, functional, and esthetic recovery. Keywords: bioengineering, oral cavity, mucosal recovery

  18. Oral cavity eumycetoma

    Directory of Open Access Journals (Sweden)

    Gisele Alborghetti Nai

    2011-06-01

    Full Text Available Mycetoma is a pathological process in which eumycotic (fungal or actinomycotic causative agents from exogenous source produce grains. It is a localized chronic and deforming infectious disease of subcutaneous tissue, skin and bones. We report the first case of eumycetoma of the oral cavity in world literature. CASE REPORT: A 43-year-old male patient, complaining of swelling and fistula in the hard palate. On examination, swelling of the anterior and middle hard palate, with fistula draining a dark liquid was observed. The panoramic radiograph showed extensive radiolucent area involving the region of teeth 21-26 and the computerized tomography showed communication with the nasal cavity, suggesting the diagnosis of periapical cyst. Surgery was performed to remove the lesion. Histopathological examination revealed purulent material with characteristic grain. Gram staining for bacteria was negative and Grocott-Gomori staining for the detection of fungi was positive, concluding the diagnosis of eumycetoma. The patient was treated with ketoconazole for nine months, and was considered cured at the end of treatment. CONCLUSION: Histopathological examination, using histochemical staining, and direct microscopic grains examination can provide the distinction between eumycetoma and actinomycetoma accurately.

  19. Development of large grain cavities

    Directory of Open Access Journals (Sweden)

    W. Singer

    2013-01-01

    Full Text Available DESY activities on 1.3 GHz tesla shape single cell and nine-cell large grain (LG resonators are presented; results of the past five years are covered. The R&D program explores the potential for production of elliptical superconducting cavities. The main efforts have been devoted to material investigation, development of LG disk production, cavity fabrication from this material, and a search for appropriate treatment. More than 250 LG disks are manufactured; several single cell and 11 nine-cell resonators are produced and rf tested after buffered chemical polishing and after additional electropolishing. A maximum accelerating gradient of approximately 45  MV/m for this type of cavity was achieved in two resonators. Two of the LG cavities have been installed and are currently being used in the FLASH accelerator operation. Assembly of a cryomodule, consisting of LG cavities only, is in the works. Perspectives of the LG cavity application are discussed.

  20. Cavity quantum-electrodynamical response to a gravitational wave

    Energy Technology Data Exchange (ETDEWEB)

    Gerlach, U.H. (Department of Mathematics, Ohio State University, Columbus, Ohio 43210 (United States))

    1992-08-15

    What is the rate of information transfer from a gravitational wave (GW) transmitter to a receiver To this end we consider how electromagnetic modes in a cylindrical cavity respond to circularly polarized gravitational radiation. It is found that a GW changes the refractive index inside the cavity. In fact, the cavity interior becomes birefringent for electromagnetic modes circulating in opposite directions. A linearly polarized cavity mode is thus subjected to Faraday rotation by the GW. In addition, for a cavity mode circulating in the same sense as the GW, the refractive index becomes complex: the cavity interior exhibits antidamping, but only over a finite interval of the applied GW frequency. Inside this interval the cavity mode becomes unstable and its frequency locks onto one-half the GW frequency ( parametric excitation''). Outside this interval the cavity mode breaks the lock-in synchronization with the GW. Instead, the mode evolves in a stable fashion and, like a counterrotating mode, only suffers a frequency pulling away from its unperturbed value. The quantum-mechanical response of the cavity oscillator is expressed as a spinning top precessing around a fictitious magnetic field in a fictitious three-dimensional Lorentz space. In the absence of any impinging GW this magnetic field is timelike and straight up. In the presence of a GW this magnetic field gets changed. The vectorial change is directly related to the frequency and the maximum amplitude of the GW. The resultant magnetic field is tilted and timelike for stable evolution, but spacelike for unstable evolution. The set of observables of a simple harmonic oscillator (SHO) is decomposed into mutually exclusive and jointly exhaustive sets of spin-{ital j} objects. They make up the finite representations of the symmetry group of the three-dimensional Lorentz space arena for the cavity oscillator influenced by a GW.

  1. MEDICI reactor cavity model

    International Nuclear Information System (INIS)

    Bergeron, K.D.; Trebilcock, W.

    1983-01-01

    The MEDICI reactor cavity model is currently under development with the goal of providing a flexible, relatively realistic treatment of ex-vessel severe accident phenomena suitable for large-system codes like CONTAIN and MELCOR. The code is being developed with an emphasis on top-down design, to facilitate adaptability and multiple applications. A brief description of the overall code structure is provided. One of the key new models is then described in more detail. This is a dynamic quench model for debris beds. An example calculation using this model is presented. The question of whether it is necessary to consider the simultaneous motion of the quench front and ablation of the concrete is addressed with some scoping models

  2. Superconducting cavity model for LEP

    CERN Document Server

    CERN PhotoLab

    1979-01-01

    A superconducting cavity model is being prepared for testing in a vertical cryostat.At the top of the assembly jig is H.Preis while A.Scharding adjusts some diagnostic equipment to the cavity. See also photo 7912501X.

  3. Superconducting Storage Cavity for RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi,I.

    2009-01-02

    This document provides a top-level description of a superconducting cavity designed to store hadron beams in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It refers to more detailed documents covering the various issues in designing, constructing and operating this cavity. The superconducting storage cavity is designed to operate at a harmonic of the bunch frequency of RHIC at a relatively low frequency of 56 MHz. The current storage cavities of RHIC operate at 197 MHz and are normal-conducting. The use of a superconducting cavity allows for a high gap voltage, over 2 MV. The combination of a high voltage and low frequency provides various advantages stemming from the resulting large longitudinal acceptance bucket.

  4. Mechanical Properties of Niobium Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Dhakal, Pashupati [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Matalevich, Joseph R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Myneni, Ganapati Rao [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    The mechanical stability of bulk Nb cavity is an important aspect to be considered in relation to cavity material, geometry and treatments. Mechanical properties of Nb are typically obtained from uniaxial tensile tests of small samples. In this contribution we report the results of measurements of the resonant frequency and local strain along the contour of single-cell cavities made of ingot and fine-grain Nb of different purity subjected to increasing uniform differential pressure, up to 6 atm. Measurements have been done on cavities subjected to different heat treatments. Good agreement between finite element analysis simulations and experimental data in the elastic regime was obtained with a single set of values of Young’s modulus and Poisson’s ratio. The experimental results indicate that the yield strength of medium-purity ingot Nb cavities is higher than that of fine-grain, high-purity Nb.

  5. Changeability of oral cavity environment.

    Science.gov (United States)

    Surdacka, Anna; Strzyka A, Krystyna; Rydzewska, Anna

    2007-01-01

    In dentistry, the results of in vivo studies on drugs, dental fillings or prostheses are routinely evaluated based on selected oral cavity environment parameters at specific time points. Such evaluation may be confounded by ongoing changes in the oral cavity environment induced by diet, drug use, stress and other factors. The study aimed to confirm oral cavity environment changeability. 24 healthy individuals aged 20-30 had their oral cavity environment prepared by having professional hygiene procedures performed and caries lesions filled. Baseline examination and the examination two years afterwards, evaluated clinical and laboratory parameters of oral cavity environment. Caries incidence was determined based on DMFT and DMFS values, oral cavity hygiene on Plaque Index (acc. Silness & Loe) and Hygiene Index (acc. O'Leary), and the gingival status on Gingival Index (acc. Loe & Silness) and Gingival Bleeding Index (acc. Ainamo & Bay). Saliva osmolarity, pH and concentrations of Ca(2+), Pi, Na(+), Cl(-), total protein, albumins, F(-) and Sr(2+) were determined. The results confirmed ongoing changeability of the oral cavity environment. After 2 years of the study reduction in oral cavity hygiene parameters PLI and HI (P<0.1), and gingival indices as well as lower saliva concentration of Ca(2+) (P<.001), Pi (P<.06), K(+) (P<.04), Sr(2+) (P<.03), Na(+) (P<.1), against the baseline values, were observed. Total protein and albumin saliva concentrations were also significantly lower. Physiological oral cavity environment is subject to constant, individually different, changes which should be considered when analysing studies that employ oral cavity environment parameters.

  6. The quest for high-gradient superconducting cavities

    International Nuclear Information System (INIS)

    Padamsee, H.

    1999-01-01

    Superconducting RF cavities excel in applications requiring continuous waves or long pulse voltages. Since power losses in the walls of the cavity increase as the square of the accelerating voltage, copper cavities become uneconomical as demand for high continuous wave voltage grows with particle energy. For these reasons, RF superconductivity has become an important technology for high energy and high luminosity accelerators. The state of art in performance of sheet metal niobium cavities is best represented by the statistics of more than 300 5-cell, 1.5-GHz cavities built for CEBAF. Key aspects responsible for the outstanding performance of the CEBAF cavities set are the anti-multipactor, elliptical cell shape, good fabrication and welding techniques, high thermal conductivity niobium, and clean surface preparation. On average, field emission starts at the electric field of 8.7 MV/m, but there is a large spread, even though the cavities received nominally the same surface treatment and assembly procedures. In some cavities, field emission was detected as low as 3 MV/m. In others, it was found to be as high as 19 MV/m. As we will discuss, the reason for the large spread in the gradients is the large spread in emitter characteristics and the random occurrence of emitters on the surface. One important phenomenon that limits the achievable RF magnetic field is thermal breakdown of superconductivity, originating at sub-millimeter-size regions of high RF loss, called defects. Simulation reveal that if the defect is a normal conducting region of 200 mm radius, it will break down at 5 MV/m. Producing high gradients and high Q in superconducting cavities demands excellent control of material properties and surface cleanliness. The spread in gradients that arises from the random occurrence of defects and emitters must be reduced. It will be important to improve installation procedures to preserve the excellent gradients now obtained in laboratory test in vertical cryostats

  7. Nonlocal Intracranial Cavity Extraction

    Science.gov (United States)

    Manjón, José V.; Eskildsen, Simon F.; Coupé, Pierrick; Romero, José E.; Collins, D. Louis; Robles, Montserrat

    2014-01-01

    Automatic and accurate methods to estimate normalized regional brain volumes from MRI data are valuable tools which may help to obtain an objective diagnosis and followup of many neurological diseases. To estimate such regional brain volumes, the intracranial cavity volume (ICV) is often used for normalization. However, the high variability of brain shape and size due to normal intersubject variability, normal changes occurring over the lifespan, and abnormal changes due to disease makes the ICV estimation problem challenging. In this paper, we present a new approach to perform ICV extraction based on the use of a library of prelabeled brain images to capture the large variability of brain shapes. To this end, an improved nonlocal label fusion scheme based on BEaST technique is proposed to increase the accuracy of the ICV estimation. The proposed method is compared with recent state-of-the-art methods and the results demonstrate an improved performance both in terms of accuracy and reproducibility while maintaining a reduced computational burden. PMID:25328511

  8. Nonlocal Intracranial Cavity Extraction

    Directory of Open Access Journals (Sweden)

    José V. Manjón

    2014-01-01

    Full Text Available Automatic and accurate methods to estimate normalized regional brain volumes from MRI data are valuable tools which may help to obtain an objective diagnosis and followup of many neurological diseases. To estimate such regional brain volumes, the intracranial cavity volume (ICV is often used for normalization. However, the high variability of brain shape and size due to normal intersubject variability, normal changes occurring over the lifespan, and abnormal changes due to disease makes the ICV estimation problem challenging. In this paper, we present a new approach to perform ICV extraction based on the use of a library of prelabeled brain images to capture the large variability of brain shapes. To this end, an improved nonlocal label fusion scheme based on BEaST technique is proposed to increase the accuracy of the ICV estimation. The proposed method is compared with recent state-of-the-art methods and the results demonstrate an improved performance both in terms of accuracy and reproducibility while maintaining a reduced computational burden.

  9. Frequency-feedback cavity enhanced spectrometer

    Science.gov (United States)

    Hovde, David Christian; Gomez, Anthony

    2015-08-18

    A spectrometer comprising an optical cavity, a light source capable of producing light at one or more wavelengths transmitted by the cavity and with the light directed at the cavity, a detector and optics positioned to collect light transmitted by the cavity, feedback electronics causing oscillation of amplitude of the optical signal on the detector at a frequency that depends on cavity losses, and a sensor measuring the oscillation frequency to determine the cavity losses.

  10. Electronic warfare receivers and receiving systems

    CERN Document Server

    Poisel, Richard A

    2014-01-01

    Receivers systems are considered the core of electronic warfare (EW) intercept systems. Without them, the fundamental purpose of such systems is null and void. This book considers the major elements that make up receiver systems and the receivers that go in them.This resource provides system design engineers with techniques for design and development of EW receivers for modern modulations (spread spectrum) in addition to receivers for older, common modulation formats. Each major module in these receivers is considered in detail. Design information is included as well as performance tradeoffs o

  11. Radiotherapy for Oral Cavity Cancer

    International Nuclear Information System (INIS)

    Shim, Jae Won

    1993-01-01

    Eighty five patients of oral cavity cancer, treated with radiation at the Department of Therapeutic Radiology, Korea Cancer Center Hospital, during the period from March 1985 to September 1990 were analyzed retrospectively. Among 85 patients, 37 patients were treated with radiation only and 48 patients were treated with radiation following surgery And 70 patients received external irradiation only by 60 Co with or without electron, the others were 7 patients for external irradiation plus interstitial implantation and 8 patients for external irradiation plus oral cone electron therapy. Primary sites were mobile tongue for 40 patients, mouth floor for 17 patients, palate for 12 patients, gingiva including retromolar trigone for 10 patients, buccal mucosa for 5 patients, and lip for 1 patient. According to pathologic classification, squamous cell carcinoma was the most common (77 patients). According to AJC TNM stage, stage I + II were 28 patients and stage III + IV were 57 patients. Acturial overall survival rate at 3 years was 43.9%, 3 year survival rates were 60.9% for stage I + II, and 23.1% for stage III + IV, respectively. As a prognostic factor, primary T stage was a significant factor (p<0.01). The others, age, location, lymph node metastasis, surgery, radiation dose, and cell differentiation were not statistically significant. Among those factors, radiation plus surgery was more effective than radiation only in T3 + T4 or in any N stage although it was not statistically sufficient(p<0.1). From those results, it was conclusive that definitive radiotherapy was more effective than surgery especially in the view of pertaining of anatomical integrity and function in early stage, and radiation plus surgery was considered to be better therapeutic tool in advanced stage

  12. Bistability of Cavity Magnon Polaritons

    Science.gov (United States)

    Wang, Yi-Pu; Zhang, Guo-Qiang; Zhang, Dengke; Li, Tie-Fu; Hu, C.-M.; You, J. Q.

    2018-01-01

    We report the first observation of the magnon-polariton bistability in a cavity magnonics system consisting of cavity photons strongly interacting with the magnons in a small yttrium iron garnet (YIG) sphere. The bistable behaviors emerged as sharp frequency switchings of the cavity magnon polaritons (CMPs) and related to the transition between states with large and small numbers of polaritons. In our experiment, we align, respectively, the [100] and [110] crystallographic axes of the YIG sphere parallel to the static magnetic field and find very different bistable behaviors (e.g., clockwise and counter-clockwise hysteresis loops) in these two cases. The experimental results are well fitted and explained as being due to the Kerr nonlinearity with either a positive or negative coefficient. Moreover, when the magnetic field is tuned away from the anticrossing point of CMPs, we observe simultaneous bistability of both magnons and cavity photons by applying a drive field on the lower branch.

  13. Niobium LEP 2 accelerating cavities

    CERN Multimedia

    An accelerating cavity from LEP. This could be cut open to show the layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities were used in an upgrade of the LEP accelerator to double the energy of the particle beams.

  14. Loggerhead oral cavity morphometry study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Standard external morphometrics and internal oral cavity morphometrics data were collected on wild and captive reared loggerhead sea turtles in size classes ranging...

  15. SRF Cavity Fabrication and Materials

    CERN Document Server

    Singer, W

    2014-07-17

    The technological and metallurgical requirements of material for highgradient superconducting cavities are described. High-purity niobium, as the preferred metal for the fabrication of superconducting accelerating cavities, should meet exact specifications. The content of interstitial impurities such as oxygen, nitrogen, and carbon must be below 10μg/g. The hydrogen content should be kept below 2μg/g to prevent degradation of the Q-value under certain cool-down conditions. The material should be free of flaws (foreign material inclusions or cracks and laminations) that can initiate a thermal breakdown. Defects may be detected by quality control methods such as eddy current scanning and identified by a number of special methods. Conventional and alternative cavity fabrication methods are reviewed. Conventionally, niobium cavities are fabricated from sheet niobium by the formation of half-cells by deep drawing, followed by trim machining and Electron-Beam Welding (EBW). The welding of half-cells is a delicate...

  16. Bistability of Cavity Magnon Polaritons.

    Science.gov (United States)

    Wang, Yi-Pu; Zhang, Guo-Qiang; Zhang, Dengke; Li, Tie-Fu; Hu, C-M; You, J Q

    2018-02-02

    We report the first observation of the magnon-polariton bistability in a cavity magnonics system consisting of cavity photons strongly interacting with the magnons in a small yttrium iron garnet (YIG) sphere. The bistable behaviors emerged as sharp frequency switchings of the cavity magnon polaritons (CMPs) and related to the transition between states with large and small numbers of polaritons. In our experiment, we align, respectively, the [100] and [110] crystallographic axes of the YIG sphere parallel to the static magnetic field and find very different bistable behaviors (e.g., clockwise and counter-clockwise hysteresis loops) in these two cases. The experimental results are well fitted and explained as being due to the Kerr nonlinearity with either a positive or negative coefficient. Moreover, when the magnetic field is tuned away from the anticrossing point of CMPs, we observe simultaneous bistability of both magnons and cavity photons by applying a drive field on the lower branch.

  17. Squamous cell carcinoma of the oral cavity

    International Nuclear Information System (INIS)

    Lindeloev, B.; Kirkegaard, J.; Hansen, H.S.; Copenhagen Univ. Hospital

    1990-01-01

    Three hundred and four patients with squamous cell carcinomas of the oral cavity were treated at the Finsen Institute in cooperation with the ENT-surgical departments between 1978 and 1982. The primary treatment consisted of radiotherapy alone in 74%, surgery alone in 4%, and a combination of radiotherapy and surgery in 15% of the patients. 2% received other treatment (cryotherapy), 5% did not complete the planned radiotherapy, and 1% were not treated at all. Of 203 patients with tumour remnant or first recurrence, 45% were operated, 2% received radiotherapy, and 2% combined treatment. This treatment strategy made 38% of the patients free of disease in the follow-up period (3 1/2 to 8 years) or until the patients died from other causes. Fifty-nine percent of the patients died from their oral carcinomas. Tumour size (T), lymph node status (N), and tumour stage were as expected important prognostic factors. (orig.)

  18. Assessment of a Cavity to Optimize Ultrasonic Efficiency to Remove Intraradicular Posts.

    Science.gov (United States)

    Graça, Izabela Araujo Aguiar; Sponchiado Júnior, Emílio Carlos; Marques, André Augusto Franco; de Moura Martins, Leandro; Garrido, Ângela Delfina Bittencourt

    2017-08-01

    The study assessed an in vitro protocol for the removal of cast metal posts using ultrasonic vibration in multirooted teeth by drilling a cavity in the coronal portion of the post followed by ultrasound application in the cavity. Forty endodontically treated molars received intraradicular cast posts and were divided into 4 groups according to the removal protocol: the control group, no cavity and no ultrasonic vibration; the ultrasonic group, no cavity and ultrasonic vibration in the coronal portion of the core; the cavity group, a cavity in the core and no ultrasonic vibration; and the cavity ultrasonic group, a cavity in the core and ultrasonic vibration inside the cavity. The traction test was performed on all samples using a universal testing machine (EMIC DL-2000; EMIC Equipamentos e Sistemas de Ensaio LTDA, São José dos Pinhais, PR, Brazil) at a speed of 1 mm/min, obtaining values in Newtons. The data were statistically analyzed using analysis of variance and the Tukey-Kramer test (P ultrasonic group = 283.09 N, cavity group = 244.00 N, and cavity ultrasonic group = 237.69 N). The lowest mean strength was found in the group that received ultrasonic vibration inside the cavity. Preparing a cavity in the coronal core followed by ultrasonic vibration reduces the traction force required for removal. The removal protocol was effective for removing posts in multirooted teeth cemented with zinc phosphate. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  19. Transmitter-receiver system

    NARCIS (Netherlands)

    De Weerdt, E.; Van Kampen, E.J.; Chu, Q.P.

    2009-01-01

    The invention relates to a transmitter-receiver system comprising at least three transmitters and at least a first receiver and a second receiver, wherein the receivers are connected to a computing device that is arranged to analyse signals that said receivers receive from said transmitters and to

  20. Sterility of the uterine cavity

    DEFF Research Database (Denmark)

    Møller, Birger R.; Kristiansen, Frank V.; Thorsen, Poul

    1995-01-01

    In a prospective open study the sterility of the uterine cavity was evaluated in 99 women admitted for hysterectomy. The indications for hysterectomy were in most cases persistent irregular vaginal bleeding and fibromyomas of the uterus. Samples for both aerobic and anaerobic bacteria, Chlamydia ...... which may play a causative role in endometritis. The results indicate that inflammation of the uterine cavity should be evaluated by hysteroscopic examination before hysterectomy is undertaken in patients with persistent irregular vaginal bleeding. Udgivelsesdato: 1995-Mar...

  1. LEP Radio Frequency Copper Cavity

    CERN Multimedia

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  2. 21 CFR 872.3260 - Cavity varnish.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cavity varnish. 872.3260 Section 872.3260 Food and... DENTAL DEVICES Prosthetic Devices § 872.3260 Cavity varnish. (a) Identification. Cavity varnish is a device that consists of a compound intended to coat a prepared cavity of a tooth before insertion of...

  3. Inter-assemblage facilitation: the functional diversity of cavity-producing beetles drives the size diversity of cavity-nesting bees.

    Science.gov (United States)

    Sydenham, Markus A K; Häusler, Lise D; Moe, Stein R; Eldegard, Katrine

    2016-01-01

    Inter-specific interactions are important drivers and maintainers of biodiversity. Compared to trophic and competitive interactions, the role of non-trophic facilitation among species has received less attention. Cavity-nesting bees nest in old beetle borings in dead wood, with restricted diameters corresponding to the body size of the bee species. The aim of this study was to test the hypothesis that the functional diversity of cavity-producing wood boring beetles - in terms of cavity diameters - drives the size diversity of cavity-nesting bees. The invertebrate communities were sampled in 30 sites, located in forested landscapes along an elevational gradient. We regressed the species richness and abundance of cavity nesting bees against the species richness and abundance of wood boring beetles, non-wood boring beetles and elevation. The proportion of cavity nesting bees in bee species assemblage was regressed against the species richness and abundance of wood boring beetles. We also tested the relationships between the size diversity of cavity nesting bees and wood boring beetles. The species richness and abundance of cavity nesting bees increased with the species richness and abundance of wood boring beetles. No such relationship was found for non-wood boring beetles. The abundance of wood boring beetles was also related to an increased proportion of cavity nesting bee individuals. Moreover, the size diversity of cavity-nesting bees increased with the functional diversity of wood boring beetles. Specifically, the mean and dispersion of bee body sizes increased with the functional dispersion of large wood boring beetles. The positive relationships between cavity producing bees and cavity nesting bees suggest that non-trophic facilitative interactions between species assemblages play important roles in organizing bee species assemblages. Considering a community-wide approach may therefore be required if we are to successfully understand and conserve wild bee

  4. Engineering interactions between long-lived cavities

    Science.gov (United States)

    Gao, Yvonne; Rosenblum, Serge; Reinhold, Philip; Wang, Chen; Axline, Christopher; Frunzio, Luigi; Girvin, Steven M.; Jiang, Liang; Mirrahimi, Mazyar; Devoret, Michel H.; Schoelkopf, Robert J.

    The availability of large Hilbert dimensions and outstanding coherence properties make superconducting cavities promising systems for storing quantum information. Recent experiments in cQED has demonstrated that redundantly encoding logical qubits in such cavities is a hardware-efficient approach toward error-correctable quantum memories. In order to tap into the power of these protected memories for quantum information processing, robust inter-cavity operations are required. A simple way to realise such operations between two cavities is using the non-linearity of the Josephson junction. To do so, we adopt a multi-cavity architecture where a fixed-frequency, single junction transmon simultaneously couples to two highly coherent 3D cavities. Using only external RF drives, we demonstrate transmon-cavity as well as cavity-cavity SWAP operations and show that such interactions are essential building blocks for implementing multi-cavity conditional logics.

  5. Thermal conditions within tree cavities in ponderosa pine (Pinus ponderosa) forests: potential implications for cavity users

    Science.gov (United States)

    Vierling, Kerri T.; Lorenz, Teresa J.; Cunningham, Patrick; Potterf, Kelsi

    2017-11-01

    Tree cavities provide critical roosting and breeding sites for multiple species, and thermal environments in these cavities are important to understand. Our objectives were to (1) describe thermal characteristics in cavities between June 3 and August 9, 2014, and (2) investigate the environmental factors that influence cavity temperatures. We placed iButtons in 84 different cavities in ponderosa pine (Pinus ponderosa) forests in central Washington, and took hourly measurements for at least 8 days in each cavity. Temperatures above 40 °C are generally lethal to developing avian embryos, and 18% of the cavities had internal temperatures of ≥ 40 °C for at least 1 h of each day. We modeled daily maximum cavity temperature, the amplitude of daily cavity temperatures, and the difference between the mean internal cavity and mean ambient temperatures as a function of several environmental variables. These variables included canopy cover, tree diameter at cavity height, cavity volume, entrance area, the hardness of the cavity body, the hardness of the cavity sill (which is the wood below the cavity entrance which forms the barrier between the cavity and the external environment), and sill width. Ambient temperature had the largest effect size for maximum cavity temperature and amplitude. Larger trees with harder sills may provide more thermally stable cavity environments, and decayed sills were positively associated with maximum cavity temperatures. Summer temperatures are projected to increase in this region, and additional research is needed to determine how the thermal environments of cavities will influence species occupancy, breeding, and survival.

  6. Quasistatic Cavity Resonance for Ubiquitous Wireless Power Transfer.

    Directory of Open Access Journals (Sweden)

    Matthew J Chabalko

    Full Text Available Wireless power delivery has the potential to seamlessly power our electrical devices as easily as data is transmitted through the air. However, existing solutions are limited to near contact distances and do not provide the geometric freedom to enable automatic and un-aided charging. We introduce quasistatic cavity resonance (QSCR, which can enable purpose-built structures, such as cabinets, rooms, and warehouses, to generate quasistatic magnetic fields that safely deliver kilowatts of power to mobile receivers contained nearly anywhere within. A theoretical model of a quasistatic cavity resonator is derived, and field distributions along with power transfer efficiency are validated against measured results. An experimental demonstration shows that a 54 m3 QSCR room can deliver power to small coil receivers in nearly any position with 40% to 95% efficiency. Finally, a detailed safety analysis shows that up to 1900 watts can be transmitted to a coil receiver enabling safe and ubiquitous wireless power.

  7. Receiver Test Selection Criteria

    Science.gov (United States)

    2015-03-12

    The DOT requests that GPS manufacturers submit receivers for test in the following TWG categories: - Aviation (non-certified), cellular, general location/navigation, high precision, timing, networks, and space-based receivers - Each receiver should b...

  8. Cavity QED with atomic mirrors

    Science.gov (United States)

    Chang, D. E.; Jiang, L.; Gorshkov, A. V.; Kimble, H. J.

    2012-06-01

    A promising approach to merge atomic systems with scalable photonics has emerged recently, which consists of trapping cold atoms near tapered nanofibers. Here, we describe a novel technique to achieve strong, coherent coupling between a single atom and photon in such a system. Our approach makes use of collective enhancement effects, which allow a lattice of atoms to form a high-finesse cavity within the fiber. We show that a specially designated ‘impurity’ atom within the cavity can experience strongly enhanced interactions with single photons in the fiber. Under realistic conditions, a ‘strong coupling’ regime can be reached, wherein it becomes feasible to observe vacuum Rabi oscillations between the excited impurity atom and a single cavity quantum. This technique can form the basis for a scalable quantum information network using atom-nanofiber systems.

  9. A SURVEY OF CORONAL CAVITY DENSITY PROFILES

    International Nuclear Information System (INIS)

    Fuller, J.; Gibson, S. E.

    2009-01-01

    Coronal cavities are common features of the solar corona that appear as darkened regions at the base of coronal helmet streamers in coronagraph images. Their darkened appearance indicates that they are regions of lowered density embedded within the comparatively higher density helmet streamer. Despite interfering projection effects of the surrounding helmet streamer (which we refer to as the cavity rim), Fuller et al. have shown that under certain conditions it is possible to use a Van de Hulst inversion of white-light polarized brightness (pB) data to calculate the electron density of both the cavity and cavity rim plasma. In this article, we apply minor modifications to the methods of Fuller et al. in order to improve the accuracy and versatility of the inversion process, and use the new methods to calculate density profiles for both the cavity and cavity rim in 24 cavity systems. We also examine trends in cavity morphology and how departures from the model geometry affect our density calculations. The density calculations reveal that in all 24 cases the cavity plasma has a flatter density profile than the plasma of the cavity rim, meaning that the cavity has a larger density depletion at low altitudes than it does at high altitudes. We find that the mean cavity density is over four times greater than that of a coronal hole at an altitude of 1.2 R sun and that every cavity in the sample is over twice as dense as a coronal hole at this altitude. Furthermore, we find that different cavity systems near solar maximum span a greater range in density at 1.2 R sun than do cavity systems near solar minimum, with a slight trend toward higher densities for systems nearer to solar maximum. Finally, we found no significant correlation of cavity density properties with cavity height-indeed, cavities show remarkably similar density depletions-except for the two smallest cavities that show significantly greater depletion.

  10. Coeliac cavity ultrasonic diagnosis apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Ando, O.; Suwaki, T.

    1983-07-05

    A coeliac cavity ultrasonic diagnosis apparatus is disclosed which includes an ultrasonic transducer or scanner portion adapted to be inserted into a coeliac cavity to effect a sector scan of an ultrasonic beam to produce an ultrasonic image of internal tissues and in which the ultrasonic oscillator on the one hand and an ultrasonic reflecting mirror and rotary disc on the other hand are relatively rotated so as to effect the sector scan of the ultrasonic beam and the rotary angle of the rotary disc is detected so as to obtain a deflecting angle of the ultrasonic beam and a display on a cathode ray tube of a precise ultrasonic picture image.

  11. Protein dynamics: hydration and cavities

    Directory of Open Access Journals (Sweden)

    Heremans K.

    2005-01-01

    Full Text Available The temperature-pressure behavior of proteins seems to be unique among the biological macromolecules. Thermodynamic as well as kinetic data show the typical elliptical stability diagram. This may be extended by assuming that the unfolded state gives rise to volume and enthalpy-driven liquid-liquid transitions. A molecular interpretation follows from the temperature and the pressure dependence of the hydration and cavities. We suggest that positron annihilation spectroscopy can provide additional quantitative evidence for the contributions of cavities to the dynamics of proteins. Only mature amyloid fibrils that form from unfolded proteins are very resistant to pressure treatment.

  12. A heat receiver design for solar dynamic space power systems

    Science.gov (United States)

    Baker, Karl W.; Dustin, Miles O.; Crane, Roger

    1990-01-01

    An advanced heat pipe receiver designed for a solar dynamic space power system is described. The power system consists of a solar concentrator, solar heat receiver, Stirling heat engine, linear alternator and waste heat radiator. The solar concentrator focuses the sun's energy into a heat receiver. The engine and alternator convert a portion of this energy to electric power and the remaining heat is rejected by a waste heat radiator. Primary liquid metal heat pipes transport heat energy to the Stirling engine. Thermal energy storage allows this power system to operate during the shade portion of an orbit. Lithium fluoride/calcium fluoride eutectic is the thermal energy storage material. Thermal energy storage canisters are attached to the midsection of each heat pipe. The primary heat pipes pass through a secondary vapor cavity heat pipe near the engine and receiver interface. The secondary vapor cavity heat pipe serves three important functions. First, it smooths out hot spots in the solar cavity and provides even distribution of heat to the engine. Second, the event of a heat pipe failure, the secondary heat pipe cavity can efficiently transfer heat from other operating primary heat pipes to the engine heat exchanger of the defunct heat pipe. Third, the secondary heat pipe vapor cavity reduces temperature drops caused by heat flow into the engine. This unique design provides a high level of reliability and performance.

  13. Conduction cooling systems for linear accelerator cavities

    Science.gov (United States)

    Kephart, Robert

    2017-05-02

    A conduction cooling system for linear accelerator cavities. The system conducts heat from the cavities to a refrigeration unit using at least one cavity cooler interconnected with a cooling connector. The cavity cooler and cooling connector are both made from solid material having a very high thermal conductivity of approximately 1.times.10.sup.4 W m.sup.-1 K.sup.-1 at temperatures of approximately 4 degrees K. This allows for very simple and effective conduction of waste heat from the linear accelerator cavities to the cavity cooler, along the cooling connector, and thence to the refrigeration unit.

  14. Hybrid Vertical-Cavity Laser

    DEFF Research Database (Denmark)

    2010-01-01

    The present invention provides a light source (2) for light circuits on a silicon platform (3). A vertical laser cavity is formed by a gain region (101) arranged between a top mirror (4) and a bottom grating-mirror (12) in a grating region (11) in a silicon layer (10) on a substrate. A waveguide ...

  15. "Grinding" cavities in polyurethane foam

    Science.gov (United States)

    Brower, J. R.; Davey, R. E.; Dixon, W. F.; Robb, P. H.; Zebus, P. P.

    1980-01-01

    Grinding tool installed on conventional milling machine cuts precise cavities in foam blocks. Method is well suited for prototype or midsize production runs and can be adapted to computer control for mass production. Method saves time and materials compared to bonding or hot wire techniques.

  16. On the collapse of cavities

    Science.gov (United States)

    Bourne, N. K.

    The collapse of a single cavity, or a cloud of bubbles has several physical consequences when in proximity to a structure or resident within a material during deformation. The earliest recognized of these was cavitation erosion of the propellers of steam ships. However, other processes include the rapid collapse of cavities leading to hot spots in explosives from which reaction ensues, or the more recent phenomenon of light generation by oscillating single bubbles or clouds. In the collapse of a cavity, the least considered but the most important mechanism is asymmetric closure. One of the consequences of this is the formation of jets leading to local high pressures and shears that result in the damage or reaction mechanisms observed. The challenge for the future remains in understanding the effects of cloud cavitation since it is likely that only one bubble in perhaps millions in a cloud catalyses an event. The review follows the author's work in the understanding of shock-induced cavity collapse and highlights several results which indicate the importance of this problem in a variety of fields.

  17. A 200 MHz prebunching cavity

    CERN Multimedia

    1977-01-01

    This cavity was installed in the PS ring and proved very efficient in providing a modulation on the PS beam before it is injected into the SPS machine. Moreover it allowed longitudinal instabilities studies at high intensities. Roberto Cappi stands on the left.

  18. Improving cooling of cavity blackbodies

    Science.gov (United States)

    Barrat, Catherine; Chauvel, Gildas

    2013-10-01

    A cavity blackbody is the appropriate IR reference source for IR sensors which require high radiance levels. It combines high emissivity independent from wavelength and high speed warm up and high stability thanks to its light trap structure. However, the inconvenient of this structure is that it leads to a prohibitive cooling time. HGH developed a method to speed up the cooling time.

  19. Seismic resonances of acoustic cavities

    Science.gov (United States)

    Schneider, F. M.; Esterhazy, S.; Perugia, I.; Bokelmann, G.

    2016-12-01

    The goal of an On-Site Inspection (OSI) is to clarify at a possible testsite whether a member state of the Comprehensive nuclear Test Ban Treaty (CTBT)has violated its rules by conducting a underground nuclear test. Compared toatmospheric and underwater tests underground nuclear explosions are the mostdifficult to detect.One primary structural target for the field team during an OSI is the detectionof an underground cavity, created by underground nuclear explosions. Theapplication of seismic-resonances of the cavity for its detection has beenproposed in the CTBT by mentioning "resonance seismometry" as possibletechnique during OSIs. We modeled the interaction of a seismic wave-field withan underground cavity by a sphere filled with an acoustic medium surrounded byan elastic full space. For this setting the solution of the seismic wave-fieldcan be computed analytically. Using this approach the appearance of acousticresonances can be predicted in the theoretical calculations. Resonance peaksappear in the spectrum derived for the elastic domain surrounding the acousticcavity, which scale in width with the density of the acoustic medium. For lowdensities in the acoustic medium as for an gas-filled cavity, the spectralpeaks become very narrow and therefore hard to resolve. The resonancefrequencies, however can be correlated to the discrete set of eigenmodes of theacoustic cavity and can thus be predicted if the dimension of the cavity isknown. Origin of the resonance peaks are internal reverberations of wavescoupling in the acoustic domain and causing an echoing signal that couples outto the elastic domain again. In the gas-filled case the amplitudes in timedomain are very low.Beside theoretical considerations we seek to find real data examples fromsimilar settings. As example we analyze a 3D active seismic data set fromFelsőpetény, Hungary that has been conducted between 2012 and 2014 on behalf ofthe CTBTO. In the subsurface of this area a former clay mine is

  20. Waveguide based external cavity semiconductor lasers

    NARCIS (Netherlands)

    Oldenbeuving, Ruud; Klein, E.J.; Offerhaus, Herman L.; Lee, Christopher James; Verhaegen, M.; Boller, Klaus J.

    2012-01-01

    We report on progress of the project waveguide based external cavity semiconductor laser (WECSL) arrays. Here we present the latest results on our efforts to mode lock an array of tunable, external cavity semiconductor lasers.

  1. Optical cavity furnace for semiconductor wafer processing

    Science.gov (United States)

    Sopori, Bhushan L.

    2014-08-05

    An optical cavity furnace 10 having multiple optical energy sources 12 associated with an optical cavity 18 of the furnace. The multiple optical energy sources 12 may be lamps or other devices suitable for producing an appropriate level of optical energy. The optical cavity furnace 10 may also include one or more reflectors 14 and one or more walls 16 associated with the optical energy sources 12 such that the reflectors 14 and walls 16 define the optical cavity 18. The walls 16 may have any desired configuration or shape to enhance operation of the furnace as an optical cavity 18. The optical energy sources 12 may be positioned at any location with respect to the reflectors 14 and walls defining the optical cavity. The optical cavity furnace 10 may further include a semiconductor wafer transport system 22 for transporting one or more semiconductor wafers 20 through the optical cavity.

  2. An economical wireless cavity-nest viewer

    Science.gov (United States)

    Daniel P. Huebner; Sarah R. Hurteau

    2007-01-01

    Inspection of cavity nests and nest boxes is often required during studies of cavity-nesting birds, and fiberscopes and pole-mounted video cameras are sometimes used for such inspection. However, the cost of these systems may be prohibitive for some potential users. We describe a user-built, wireless cavity viewer that can be used to access cavities as high as 15 m and...

  3. Cavity QED experiments with ion Coulomb crystals

    DEFF Research Database (Denmark)

    Herskind, Peter Fønss; Dantan, Aurélien; Marler, Joan

    2009-01-01

    Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained.......Cavity QED experimental results demonstrating collective strong coupling between ensembles of atomic ions cooled into Coulomb crystals and optical cavity fields have been achieved. Collective Zeeman coherence times of milliseconds have furthermore been obtained....

  4. Solar heat receiver

    Science.gov (United States)

    Hunt, Arlon J.; Hansen, Leif J.; Evans, David B.

    1985-01-01

    A receiver for converting solar energy to heat a gas to temperatures from 700.degree.-900.degree. C. The receiver is formed to minimize impingement of radiation on the walls and to provide maximum heating at and near the entry of the gas exit. Also, the receiver is formed to provide controlled movement of the gas to be heated to minimize wall temperatures. The receiver is designed for use with gas containing fine heat absorbing particles, such as carbon particles.

  5. Diagram of a LEP superconducting cavity

    CERN Multimedia

    1991-01-01

    This diagram gives a schematic representation of the superconducting radio-frequency cavities at LEP. Liquid helium is used to cool the cavity to 4.5 degrees above absolute zero so that very high electric fields can be produced, increasing the operating energy of the accelerator. Superconducting cavities were used only in the LEP-2 phase of the accelerator, from 1996 to 2000.

  6. Gastrophysics of the Oral Cavity.

    Science.gov (United States)

    Mouritsen, Ole G

    2016-01-01

    Gastrophysics is the science that pertains to the physical and physico-chemical description of the empirical world of gastronomy, with focus on sensory perception in the oral cavity and how it is related to the materials properties of food and cooking processes. Flavor (taste and smell), mouthfeel, chemesthesis, and astringency are all related to the chemical properties and the texture of the food and how the food is transformed in the oral cavity. The present topical review will primarily focus attention on the somatosensory perception of food (mouthfeel or texture) and how it interacts with basic tastes (sour, bitter, sweet, salty, and umami) and chemesthetic action. Issues regarding diet, nutrition, and health will be put into an evolutionary perspective, and some mention will be made of umami and its importance for (oral) health.

  7. A micropillar for cavity optomechanics

    Science.gov (United States)

    Kuhn, Aurélien; Neuhaus, Leonhard; Van Brackel, Emmanuel; Chartier, Claude; Ducloux, Olivier; Le Traon, Olivier; Michel, Christophe; Pinard, Laurent; Flaminio, Raffaele; Deléglise, Samuel; Briant, Tristan; Cohadon, Pierre-François; Heidmann, Antoine

    2014-12-01

    Demonstrating the quantum ground state of a macroscopic mechanical object is a major experimental challenge in physics, at the origin of the rapid emergence of cavity optomechanics. We have developed a new generation of optomechanical devices, based on a microgram quartz micropillar with a very high mechanical quality factor. The structure is used as end mirror in a Fabry-Perot cavity with a high optical finesse, leading to ultra-sensitive interferometric measurement of the resonator displacement. We expect to reach the ground state of this optomechanical resonator by combining cryogenic cooling in a dilution fridge at 30 mK and radiation-pressure cooling. We have already carried out a quantum-limited measurement of the micropillar thermal noise at low temperature.

  8. Droplet based cavities and lasers

    DEFF Research Database (Denmark)

    Mølhave, Kristian; Kristensen, Anders; Mortensen, Asger

    2009-01-01

    The self-organized and molecularly smooth surface on liquid microdroplets makes them attractive as optical cavities with very high quality factors. This chapter describes the basic theory of optical modes in spherical droplets. The mechanical properties including vibrational excitation are also...... described, and their implications for microdroplet resonator technology are discussed. Optofluidic implementations of microdroplet resonators are reviewed with emphasis on the basic optomechanical properties....

  9. Optomechanic interactions in phoxonic cavities

    Directory of Open Access Journals (Sweden)

    Bahram Djafari-Rouhani

    2014-12-01

    Full Text Available Phoxonic crystals are periodic structures exhibiting simultaneous phononic and photonic band gaps, thus allowing the confinement of both excitations in the same cavity. The phonon-photon interaction can be enhanced due to the overlap of both waves in the cavity. In this paper, we discuss some of our recent theoretical works on the strength of the optomechanic coupling, based on both photoelastic and moving interfaces mechanisms, in different (2D, slabs, strips phoxonic crystals cavities. The cases of two-dimensional infinite and slab structures will enable us to mention the important role of the symmetry and degeneracy of the modes, as well as the role of the materials whose photoelastic constants can be wavelength dependent. Depending on the phonon-photon pair, the photoelastic and moving interface mechanisms can contribute in phase or out-of-phase. Then, the main part of the paper will be devoted to the optomechanic interaction in a corrugated nanobeam waveguide exhibiting dual phononic/photonic band gaps. Such structures can provide photonic modes with very high quality factor, high frequency phononic modes of a few GHz inside a gap and optomechanical coupling rate reaching a few MHz.

  10. Optomechanic interactions in phoxonic cavities

    Energy Technology Data Exchange (ETDEWEB)

    Djafari-Rouhani, Bahram; Oudich, Mourad; Pennec, Yan [Institut d’Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, UFR de physique, Université Lille1, Cité Scientifique, 59652, Villeneuve d’Ascq (France); El-Jallal, Said [Institut d’Electronique, de Microélectronique et de Nanotechnologie (IEMN), UMR CNRS 8520, UFR de physique, Université Lille1, Cité Scientifique, 59652, Villeneuve d’Ascq (France); Physique du Rayonnement et de l’Interaction Laser Matière, Faculté des sciences, Université de Moulay Ismail, Meknès (Morocco)

    2014-12-15

    Phoxonic crystals are periodic structures exhibiting simultaneous phononic and photonic band gaps, thus allowing the confinement of both excitations in the same cavity. The phonon-photon interaction can be enhanced due to the overlap of both waves in the cavity. In this paper, we discuss some of our recent theoretical works on the strength of the optomechanic coupling, based on both photoelastic and moving interfaces mechanisms, in different (2D, slabs, strips) phoxonic crystals cavities. The cases of two-dimensional infinite and slab structures will enable us to mention the important role of the symmetry and degeneracy of the modes, as well as the role of the materials whose photoelastic constants can be wavelength dependent. Depending on the phonon-photon pair, the photoelastic and moving interface mechanisms can contribute in phase or out-of-phase. Then, the main part of the paper will be devoted to the optomechanic interaction in a corrugated nanobeam waveguide exhibiting dual phononic/photonic band gaps. Such structures can provide photonic modes with very high quality factor, high frequency phononic modes of a few GHz inside a gap and optomechanical coupling rate reaching a few MHz.

  11. Investigation of superconducting niobium 1170 MHz cavities

    International Nuclear Information System (INIS)

    Anashin, V.V.; Bibko, S.I.; Fadeyev, E.I.

    1988-01-01

    The design, fabrication and experiments with superconducting L-band single cell cavities are described. These cavities model a cell of an accelerating RF structure. The cavities have been fabricated from technical grade and higher purity grade sheet niobium using deep-drawing, electron beam welding and chemical polishing. They have spherical geometry and are excited in the TM 010 mode. A computerized set-up was used for cavity tests. Qo=1.5 x 10 9 and E acc = 4.3 MV/m were obtained in the cavity made of higher purity grade niobium. 6 references, 8 figures, 3 tables

  12. Cavity Optomechanics at Millikelvin Temperatures

    Science.gov (United States)

    Meenehan, Sean Michael

    The field of cavity optomechanics, which concerns the coupling of a mechanical object's motion to the electromagnetic field of a high finesse cavity, allows for exquisitely sensitive measurements of mechanical motion, from large-scale gravitational wave detection to microscale accelerometers. Moreover, it provides a potential means to control and engineer the state of a macroscopic mechanical object at the quantum level, provided one can realize sufficiently strong interaction strengths relative to the ambient thermal noise. Recent experiments utilizing the optomechanical interaction to cool mechanical resonators to their motional quantum ground state allow for a variety of quantum engineering applications, including preparation of non-classical mechanical states and coherent optical to microwave conversion. Optomechanical crystals (OMCs), in which bandgaps for both optical and mechanical waves can be introduced through patterning of a material, provide one particularly attractive means for realizing strong interactions between high-frequency mechanical resonators and near-infrared light. Beyond the usual paradigm of cavity optomechanics involving isolated single mechanical elements, OMCs can also be fashioned into planar circuits for photons and phonons, and arrays of optomechanical elements can be interconnected via optical and acoustic waveguides. Such coupled OMC arrays have been proposed as a way to realize quantum optomechanical memories, nanomechanical circuits for continuous variable quantum information processing and phononic quantum networks, and as a platform for engineering and studying quantum many-body physics of optomechanical meta-materials. However, while ground state occupancies (that is, average phonon occupancies less than one) have been achieved in OMC cavities utilizing laser cooling techniques, parasitic absorption and the concomitant degradation of the mechanical quality factor fundamentally limit this approach. On the other hand, the high

  13. STRUCTURAL ANALYSIS OF SUPERCONDUCTING ACCELERATOR CAVITIES

    International Nuclear Information System (INIS)

    Schrage, D.

    2000-01-01

    The static and dynamic structural behavior of superconducting cavities for various projects was determined by finite element structural analysis. The β = 0.61 cavity shape for the Neutron Science Project was studied in detail and found to meet all design requirements if fabricated from five millimeter thick material with a single annular stiffener. This 600 MHz cavity will have a Lorentz coefficient of minus1.8 Hz/(Mv/meter) 2 and a lowest structural resonance of more than 100 Hz. Cavities at β = 0.48, 0.61, and 0.77 were analyzed for a Neutron Science Project concept which would incorporate 7-cell cavities. The medium and high beta cavities were found to meet all criteria but it was not possible to generate a β = 0.48 cavity with a Lorentz coefficient of less than minus3 Hz/(Mv/meter) 2

  14. Novel Geometries for the LHC Crab Cavity

    Energy Technology Data Exchange (ETDEWEB)

    B. Hall, G. Burt, C. Lingwood, R. Rimmer, H. Wang

    2010-05-23

    The planned luminosity upgrade to LHC is likely to necessitate a large crossing angle and a local crab crossing scheme. For this scheme crab cavities align bunches prior to collision. The scheme requires at least four such cavities, a pair on each beam line either side of the interaction point (IP). Upstream cavities initiate rotation and downstream cavities cancel rotation. Cancellation is usually done at a location where the optics has re-aligned the bunch. The beam line separation near the IP necessitates a more compact design than is possible with elliptical cavities such as those used at KEK. The reduction in size must be achieved without an increase in the operational frequency to maintain compatibility with the long bunch length of the LHC. This paper proposes a suitable superconducting variant of a four rod coaxial deflecting cavity (to be phased as a crab cavity), and presents analytical models and simulations of suitable designs.

  15. Novel Geometries for the LHC Crab Cavity

    Energy Technology Data Exchange (ETDEWEB)

    B. Hall,G. Burt,C. Lingwood,Robert Rimmer,Haipeng Wang; Hall, B. [CI Lancaster University (Great Britain); Burt, G. [CI Lancaster University (Great Britain); Lingwood, C. [CI Lancaster University (Great Britain); Rimmer, Robert [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Wang, Haipeng [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2010-05-01

    The planned luminosity upgrade to LHC is likely to necessitate a large crossing angle and a local crab crossing scheme. For this scheme crab cavities align bunches prior to collision. The scheme requires at least four such cavities, a pair on each beam line either side of the interaction point (IP). Upstream cavities initiate rotation and downstream cavities cancel rotation. Cancellation is usually done at a location where the optics has re-aligned the bunch. The beam line separation near the IP necessitates a more compact design than is possible with elliptical cavities such as those used at KEK. The reduction in size must be achieved without an increase in the operational frequency to maintain compatibility with the long bunch length of the LHC. This paper proposes a suitable superconducting variant of a four rod coaxial deflecting cavity (to be phased as a crab cavity), and presents analytical models and simulations of suitable designs.

  16. Low complexity MIMO receivers

    CERN Document Server

    Bai, Lin; Yu, Quan

    2014-01-01

    Multiple-input multiple-output (MIMO) systems can increase the spectral efficiency in wireless communications. However, the interference becomes the major drawback that leads to high computational complexity at both transmitter and receiver. In particular, the complexity of MIMO receivers can be prohibitively high. As an efficient mathematical tool to devise low complexity approaches that mitigate the interference in MIMO systems, lattice reduction (LR) has been widely studied and employed over the last decade. The co-authors of this book are world's leading experts on MIMO receivers, and here they share the key findings of their research over years. They detail a range of key techniques for receiver design as multiple transmitted and received signals are available. The authors first introduce the principle of signal detection and the LR in mathematical aspects. They then move on to discuss the use of LR in low complexity MIMO receiver design with respect to different aspects, including uncoded MIMO detection...

  17. Delphi Accounts Receivable Module -

    Data.gov (United States)

    Department of Transportation — Delphi accounts receivable module contains the following data elements, but are not limited to customer information, cash receipts, line of accounting details, bill...

  18. Understanding cavity QED effects from cavity classical electrodynamics

    International Nuclear Information System (INIS)

    Taddei, M.M.; Kort-Kamp, W.J.M.; Farina, C.

    2011-01-01

    Full text: Our work intends to show how cavity classical electrodynamics can be used for achieving results with direct quantum analogues. It is shown how the classical interaction between a real radiating electric dipole and a perfectly-conducting surface can be used to obtain information about some cavity quantum electrodynamics effects related to radiative properties of atomic systems. Based on the case of an oscillating electric dipole (a classical representation of an excited atom) in front of a perfectly-conducting sphere, two main physical quantities can be computed, the classical dipole frequency shift and the change in the rate of energy loss from radiation reaction, both due to the presence of the sphere. The link from classical to quantum can be made via interpreting, for example, the dipole frequency as the atom's dominant transition frequency. The frequency shift due to the sphere can be related through E = (h/2π) to the energy shift of the system, i.e., the dispersive interaction between the atom and the sphere; while the change in energy loss can be related to the alteration of the atom's spontaneous emission due to the sphere. The amazing result is that this classical method, once corresponded classical quantities to quantum ones such as exemplified above with frequency, can predict the two above-mentioned quantum effects analytically with the correct functional dependencies on all geometric and atomic parameters, being off only by a constant pre factor. (author)

  19. Temperature Structure of a Coronal Cavity

    Science.gov (United States)

    Kucera, T. A.; Gibson, S. E.; Schmit, D. J.

    2011-01-01

    we analyze the temperature structure of a coronal cavity observed in Aug. 2007. coronal cavities are long, low-density structures located over filament neutral lines and are often seen as dark elliptical features at the solar limb in white light, EUV and x-rays. when these structures erupt they form the cavity portions of CMEs. It is important to establish the temperature structure of cavities in order to understand the thermodynamics of cavities in relation to their three-dimensional magnetic structure. To analyze the temperature we compare temperature ratios of a series of iron lines observed by the Hinode/EUv Imaging spectrometer (EIS). We also use those lines to constrain a forward model of the emission from the cavity and streamer. The model assumes a coronal streamer with a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel lenth. Temperature and density can be varied as a function of altitude both in the cavity and streamer. The general cavity morphology and the cavity and streamer density have already been modeled using data from STEREO's SECCHI/EUVI and Hinode/EIS (Gibson et al 2010 and Schmit & Gibson 2011).

  20. Cancer of the oral cavity.

    Science.gov (United States)

    Montero, Pablo H; Patel, Snehal G

    2015-07-01

    Cancer of the oral cavity is one of the most common malignancies worldwide. Although early diagnosis is relatively easy, presentation with advanced disease is not uncommon. The standard of care is primary surgical resection with or without postoperative adjuvant therapy. Improvements in surgical techniques combined with the routine use of postoperative radiation or chemoradiation therapy have resulted in improved survival. Successful treatment is predicated on multidisciplinary treatment strategies to maximize oncologic control and minimize impact of therapy on form and function. Prevention of oral cancer requires better education about lifestyle-related risk factors, and improved awareness and tools for early diagnosis. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Rebuild of Capture Cavity 1 at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Harms, E. [Fermilab; Arkan, T. [Fermilab; Borissov, E. [Fermilab; Dhanaraj, N. [Fermilab; Hocker, A. [Fermilab; Orlov, Y. [Fermilab; Peterson, T. [Fermilab; Premo, K. [Fermilab

    2014-01-01

    The front end of the proposed Advanced Superconducting Test Accelerator at Fermilab employs two single cavity cryomodules, known as 'Capture Cavity 1' and 'Capture Cavity 2', for the first stage of acceleration. Capture Cavity 1 was previously used as the accelerating structure for the A0 Photoinjector to a peak energy of ~14 MeV. In its new location a gradient of ~25 MV/m is required. This has necessitated a major rebuild of the cryomodule including replacement of the cavity with a higher gradient one. Retrofitting the cavity and making upgrades to the module required significant redesign. The design choices and their rationale, summary of the rebuild, and early test results are presented.

  2. Cantilever piezoelectric energy harvester with multiple cavities

    International Nuclear Information System (INIS)

    S Srinivasulu Raju; M Umapathy; G Uma

    2015-01-01

    Energy harvesting employing piezoelectric materials in mechanical structures such as cantilever beams, plates, diaphragms, etc, has been an emerging area of research in recent years. The research in this area is also focused on structural tailoring to improve the harvested power from the energy harvesters. Towards this aim, this paper presents a method for improving the harvested power from a cantilever piezoelectric energy harvester by introducing multiple rectangular cavities. A generalized model for a piezoelectric energy harvester with multiple rectangular cavities at a single section and two sections is developed. A method is suggested to optimize the thickness of the cavities and the number of cavities required to generate a higher output voltage for a given cantilever beam structure. The performance of the optimized energy harvesters is evaluated analytically and through experimentation. The simulation and experimental results show that the performance of the energy harvester can be increased with multiple cavities compared to the harvester with a single cavity. (paper)

  3. Unique space saving accelerator cavity design

    International Nuclear Information System (INIS)

    Kim, H.; Fugitt, J.; Crosby, F.; Johnson, R.

    1981-03-01

    A cavity with 3 series gaps was designed and modeled to operate at 70 MHz as a SuperHILAC post acceleration buncher (8.5 MeV/A). Because of a cross-coupling scheme, the 3 cells operate in the 1/2 β lambda mode instead of the β lambda mode of an Alvarez cavity. This coupling results in a cavity with diameter reduced from 3 to less than one meter and a length half that of an Alvarez cavity for the same energy gain. The 3 gaps are electrically in parallel but mechanically in series. The cavity has high Q and shunt impedance. This type of cavity appears to be useful for low velocity beams with β less than or equal to 0.2

  4. [The oral cavity condition in patients with high blood pressure].

    Science.gov (United States)

    Rosiak, Joanna; Kubić-Filiks, Beata; Szymańska, Jolanta

    2015-10-01

    The incidence of high blood pressure in adults is estimated at ca. 30-40% of the general population. Both hypertension disease and hypertensive drugs affect the condition of the patients' oral cavity. A review of the current literature shows that disorders most frequently found in the masticatory organ of patients with hypertension include: xerostomia, changes in salivary glands, gum hypertrophy, lichenoid lesions, taste disorders, and paraesthesias. The authors emphasize that patients with high blood pressure, along with the treatment of the underlying disease, should receive prophylactic and therapeutic dental care. This would enable reduction and/or elimination of unpleasant complaints, and also help prevent the emergence of secondary disorders in the patients' oral cavity as a result of hypertension pharmacotherapy. © 2015 MEDPRESS.

  5. MHD natural convection in open inclined square cavity with a heated circular cylinder

    Science.gov (United States)

    Hosain, Sheikh Anwar; Alim, M. A.; Saha, Satrajit Kumar

    2017-06-01

    MHD natural convection in open cavity becomes very important in many scientific and engineering problems, because of it's application in the design of electronic devices, solar thermal receivers, uncovered flat plate solar collectors having rows of vertical strips, geothermal reservoirs, etc. Several experiments and numerical investigations have been presented for describing the phenomenon of natural convection in open cavity for two decades. MHD natural convection and fluid flow in a two-dimensional open inclined square cavity with a heated circular cylinder was considered. The opposite wall to the opening side of the cavity was first kept to constant heat flux q, at the same time the surrounding fluid interacting with the aperture was maintained to an ambient temperature T∞. The top and bottom wall was kept to low and high temperature respectively. The fluid with different Prandtl numbers. The properties of the fluid are assumed to be constant. As a result a buoyancy force is created inside the cavity due to temperature difference and natural convection is formed inside the cavity. The Computational Fluid Dynamics (CFD) code are used to discretize the solution domain and represent the numerical result to graphical form.. Triangular meshes are used to obtain the solution of the problem. The streamlines and isotherms are produced, heat transfer parameter Nu are obtained. The results are presented in graphical as well as tabular form. The results show that heat flux decreases for increasing inclination of the cavity and the heat flux is a increasing function of Prandtl number Pr and decreasing function of Hartmann number Ha. It is observed that fluid moves counterclockwise around the cylinder in the cavity. Various recirculations are formed around the cylinder. The almost all isotherm lines are concentrated at the right lower corner of the cavity. The object of this work is to develop a Mathematical model regarding the effect of MHD natural convection flow around

  6. Design of 325 MHz spoke cavity

    International Nuclear Information System (INIS)

    Sha Peng; Huang Hong; Dai Jianping; Zu Guoquan; Li Han

    2012-01-01

    Spoke cavity can be used in the low-energy section of the proton accelerator. It has many significant advantages: compact structure, high value of R/Q, etc. The ADS (Accelerator Driven System) project will adopt many spoke cavities with different β values. Therefore, IHEP has began the research of β=0.14, 325 MHz spoke cavity. In this pa per, the dimensions, RF performances and mechanical properties of it are studied. (authors)

  7. Induced Cavities for Photonic Quantum Gates

    Science.gov (United States)

    Lahad, Ohr; Firstenberg, Ofer

    2017-09-01

    Effective cavities can be optically induced in atomic media and employed to strengthen optical nonlinearities. Here we study the integration of induced cavities with a photonic quantum gate based on Rydberg blockade. Accounting for loss in the atomic medium, we calculate the corresponding finesse and gate infidelity. Our analysis shows that the conventional limits imposed by the blockade optical depth are mitigated by the induced cavity in long media, thus establishing the total optical depth of the medium as a complementary resource.

  8. Alexandrite Lidar Receiver

    National Research Council Canada - National Science Library

    Wilkerson, Thomas

    2000-01-01

    ...". The chosen vendor, Orca Photonics, In. (Redmond, WA), in close collaboration with USU personnel, built a portable, computerized lidar system that not only is suitable as a receiver for a near IR alexandrite laser, but also contains an independent Nd...

  9. JSSG - SPACED RECEIVER MEASUREMENTS.

    Science.gov (United States)

    The height of ionospheric irregularities was measured by several laboratories belonging to the Joint Satellite Studies Group, using spaced receiver techniques. The method of analysis and results obtained are presented. (Author)

  10. Solar energy receiver

    Science.gov (United States)

    Schwartz, Jacob

    1978-01-01

    An improved long-life design for solar energy receivers provides for greatly reduced thermally induced stress and permits the utilization of less expensive heat exchanger materials while maintaining receiver efficiencies in excess of 85% without undue expenditure of energy to circulate the working fluid. In one embodiment, the flow index for the receiver is first set as close as practical to a value such that the Graetz number yields the optimal heat transfer coefficient per unit of pumping energy, in this case, 6. The convective index for the receiver is then set as closely as practical to two times the flow index so as to obtain optimal efficiency per unit mass of material.

  11. Receiver Gain Modulation Circuit

    Science.gov (United States)

    Jones, Hollis; Racette, Paul; Walker, David; Gu, Dazhen

    2011-01-01

    A receiver gain modulation circuit (RGMC) was developed that modulates the power gain of the output of a radiometer receiver with a test signal. As the radiometer receiver switches between calibration noise references, the test signal is mixed with the calibrated noise and thus produces an ensemble set of measurements from which ensemble statistical analysis can be used to extract statistical information about the test signal. The RGMC is an enabling technology of the ensemble detector. As a key component for achieving ensemble detection and analysis, the RGMC has broad aeronautical and space applications. The RGMC can be used to test and develop new calibration algorithms, for example, to detect gain anomalies, and/or correct for slow drifts that affect climate-quality measurements over an accelerated time scale. A generalized approach to analyzing radiometer system designs yields a mathematical treatment of noise reference measurements in calibration algorithms. By treating the measurements from the different noise references as ensemble samples of the receiver state, i.e. receiver gain, a quantitative description of the non-stationary properties of the underlying receiver fluctuations can be derived. Excellent agreement has been obtained between model calculations and radiometric measurements. The mathematical formulation is equivalent to modulating the gain of a stable receiver with an externally generated signal and is the basis for ensemble detection and analysis (EDA). The concept of generating ensemble data sets using an ensemble detector is similar to the ensemble data sets generated as part of ensemble empirical mode decomposition (EEMD) with exception of a key distinguishing factor. EEMD adds noise to the signal under study whereas EDA mixes the signal with calibrated noise. It is mixing with calibrated noise that permits the measurement of temporal-functional variability of uncertainty in the underlying process. The RGMC permits the evaluation of EDA by

  12. Novel Geometries for the LHC CRAB Cavity

    CERN Document Server

    Hall, Ben

    2010-01-01

    In 2017 the LHC is envisioned to increase its luminosity via an upgrade. This upgrade is likely to require a large crossing angle hence a crab cavity is required to align the bunches prior to collision. There are two possible schemes for crab cavity implementation, global and local. In a global crab cavity the crab cavity is far from the IP and the bunch rotates back and forward as it traverses around the accelerator in a closed orbit. For this scheme a two-cell elliptical squashed cavity at 800 MHz is preferred. To avoid any potential beam instabilities all the parasitic modes of the cavities must be damped strongly, however crab cavities have lower order and same order modes in addition to the usual higher order modes and hence a novel damping scheme must be used to provide sufficient damping of these modes. In the local scheme two crab cavities are placed at each side of the IP two start and stop rotation of the bunches. This would require crab cavities much smaller transversely than in the global scheme b...

  13. Mechanical Properties of Ingot Nb Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi; Dhakal, Pashupati; Kneisel, Peter; Mammosser, John; Matalevich, Joseph; Rao Myneni, Ganapati

    2014-07-01

    This contribution presents the results of measurements of the resonant frequency and of strain along the contour of a single-cell cavity made of ingot Nb subjected to increasing uniform differential pressure, up to 6 atm. The data were used to infer mechanical properties of this material after cavity fabrication, by comparison with the results from simulation calculations done with ANSYS. The objective is to provide useful information about the mechanical properties of ingot Nb cavities which can be used in the design phase of SRF cavities intended to be built with this material.

  14. Superconducting niobium cavity with cooling fins

    International Nuclear Information System (INIS)

    Isagawa, Shigeru.

    1978-04-01

    Cooling efficiency of a superconducting cavity is shown to be improved by applying a fin structure. Internal heating can be suppressed in a certain degree and the higher rf field is expected to be reached on surfaces of the cavity which is immersed in superfluid He 4 liquid. The rf measurements were made on a C-band niobium cavity with cylindrical and circular fins around the wall. Fields of 39 mT and 25 MV/m were attained for TM 010 mode cavity after surface treatments including high temperature annealing in a UHV furnace. (auth.)

  15. Design of the ILC Crab Cavity System

    Energy Technology Data Exchange (ETDEWEB)

    Adolphsen, C.; Beard, C.; Bellantoni, L.; Burt, G.; Carter, R.; Chase, B.; Church, M.; Dexter, A.; Dykes, M.; Edwards, H.; Goudket, P; Jenkins, R.; Jones, R.M.; Kalinin,; Khabiboulline, T.; Ko, K.; Latina, A.; Li, Z.; Ma, L.; McIntosh, P.; Ng, C.; /SLAC /Daresbury /Fermilab /Cockcroft Inst. Accel. Sci. Tech. /CERN

    2007-08-15

    The International Linear Collider (ILC) has a 14 mrad crossing angle in order to aid extraction of spent bunches. As a result of the bunch shape at the interaction point, this crossing angle at the collision causes a large luminosity loss which can be recovered by rotating the bunches prior to collision using a crab cavity. The ILC baseline crab cavity is a 9-cell superconducting dipole cavity operating at a frequency of 3.9 GHz. In this paper the design of the ILC crab cavity and its phase control system, as selected for the RDR in February 2007 is described in fuller detail.

  16. Primary leiomyosarcoma of peritoneal cavity

    Directory of Open Access Journals (Sweden)

    Jyotsna Naresh Bharti

    2014-03-01

    Full Text Available Leiomyosarcomas of soft tissue are the rare tumors and the retroperitoneum is the most common site involved. We report a case of primary leiomyosarcoma of the peritoneal cavity which clinically presented with suprapubic, freely mobile, nontender mass which measured 10×10 cm in size. Contrast enhanced computed tomography revealed well defined heterogenous hypodense solid cystic mass. The mass was surgically excised out in its entirety. The histopathological examination revealed spindle cells arranged in alternating fascicles having pleomorphic nuclei, indistinct margin and eosinophilic cytoplasm with foci of haemorrhage, necrosis and 5-6 mitosis/HPF. The spindle cells were immunoreactive for smooth muscle actin, desmin and negative for S-100, CD-34 and c-kit. Histopathology and immunohistochemistry were helpful in making the final confirmatory diagnosis. Leiomyosarcomas are aggressive tumors, with poor prognosis and often difficult to treat. The survival rates are lowest among all soft tissue sarcomas.

  17. Epithelial Dysplasia in Oral Cavity

    Directory of Open Access Journals (Sweden)

    Samaneh Shirani

    2014-09-01

    Full Text Available Among oral lesions, we encounter a series of malignant epithelial lesions that go through clinical and histopathologic processes in order to be diagnosed. Identifying these processes along with the etiology knowledge of these lesions is very important in prevention and early treatments. Dysplasia is the step preceding the formation of squamous cell carcinoma in lesions which have the potential to undergo dysplasia. Identification of etiological factors, clinical and histopathologic methods has been the topic of many articles. This article, reviews various articles presenting oral cavity dysplasia, new clinical methods of identifying lesions, and the immunohistochemical research which proposes various markers for providing more precise identification of such lesions. This article also briefly analyzes new treatment methods such as tissue engineering.

  18. Solar power conversion system with directionally- and spectrally-selective properties based on a reflective cavity

    Science.gov (United States)

    Boriskina, Svetlana; Kraemer, Daniel; McEnaney, Kenneth; Weinstein, Lee A.; Chen, Gang

    2018-03-13

    Solar power conversion system. The system includes a cavity formed within an enclosure having highly specularly reflecting in the IR spectrum inside walls, the enclosure having an opening to receive solar radiation. An absorber is positioned within the cavity for receiving the solar radiation resulting in heating of the absorber structure. In a preferred embodiment, the system further contains an energy conversion and storage devices thermally-linked to the absorber by heat conduction, convection, far-field or near-field thermal radiation.

  19. Hydrodynamic Drag on Streamlined Projectiles and Cavities

    KAUST Repository

    Jetly, Aditya

    2016-04-19

    The air cavity formation resulting from the water-entry of solid objects has been the subject of extensive research due to its application in various fields such as biology, marine vehicles, sports and oil and gas industries. Recently we demonstrated that at certain conditions following the closing of the air cavity formed by the initial impact of a superhydrophobic sphere on a free water surface a stable streamlined shape air cavity can remain attached to the sphere. The formation of superhydrophobic sphere and attached air cavity reaches a steady state during the free fall. In this thesis we further explore this novel phenomenon to quantify the drag on streamlined shape cavities. The drag on the sphere-cavity formation is then compared with the drag on solid projectile which were designed to have self-similar shape to that of the cavity. The solid projectiles of adjustable weight were produced using 3D printing technique. In a set of experiments on the free fall of projectile we determined the variation of projectiles drag coefficient as a function of the projectiles length to diameter ratio and the projectiles specific weight, covering a range of intermediate Reynolds number, Re ~ 104 – 105 which are characteristic for our streamlined cavity experiments. Parallel free fall experiment with sphere attached streamlined air cavity and projectile of the same shape and effective weight clearly demonstrated the drag reduction effect due to the stress-free boundary condition at cavity liquid interface. The streamlined cavity experiments can be used as the upper bound estimate of the drag reduction by air layers naturally sustained on superhydrophobic surfaces in contact with water. In the final part of the thesis we design an experiment to test the drag reduction capacity of robust superhydrophobic coatings deposited on the surface of various model vessels.

  20. 'Chaos' in superregenerative receivers

    International Nuclear Information System (INIS)

    Commercon, Jean-Claude; Badard, Robert

    2005-01-01

    The superregenerative principle has been known since the early 1920s. The circuit is extremely simple and extremely sensitive. Today, superheterodyne receivers generally supplant superregenerative receivers in most applications because there are several undesirable characteristics: poor selectivity, reradiation, etc. Superregenerative receivers undergo a revival in recent papers for wireless systems, where low cost and very low power consumption are relevant: house/building meters (such as water, energy, gas counter), personal computer environment (keyboard, mouse), etc. Another drawback is the noise level which is higher than that of a well-designed superheterodyne receiver; without an antenna input signal, the output of the receiver hears in an earphone as a waterfall noise; this sound principally is the inherent input noise amplified and detected by the circuit; however, when the input noise is negligible with respect of an antenna input signal, we are faced to an other source of 'noise' self-generated by the superregenerative working. The main objective of this paper concerns this self-generated noise coming from an exponential growing followed by a re-injection process for which the final state is a function of the phase of the input signal

  1. Central solar energy receiver

    Science.gov (United States)

    Drost, M. Kevin

    1983-01-01

    An improved tower-mounted central solar energy receiver for heating air drawn through the receiver by an induced draft fan. A number of vertically oriented, energy absorbing, fin-shaped slats are radially arranged in a number of concentric cylindrical arrays on top of the tower coaxially surrounding a pipe having air holes through which the fan draws air which is heated by the slats which receive the solar radiation from a heliostat field. A number of vertically oriented and wedge-shaped columns are radially arranged in a number of concentric cylindrical clusters surrounding the slat arrays. The columns have two mirror-reflecting sides to reflect radiation into the slat arrays and one energy absorbing side to reduce reradiation and reflection from the slat arrays.

  2. Solar central receiver reformer system for ammonia plants

    Science.gov (United States)

    1980-07-01

    An overview of a study to retrofit the Valley Nitrogen Producers, Inc., El Centro, California 600 ST/SD Ammonia Plant with Solar Central Receiver Technology is presented. The retrofit system consists of a solar central receiver reformer (SCRR) operating in parallel with the existing fossil fired reformer. Steam and hydrocarbon react in the catalyst filled tubes of the inner cavity receiver to form a hydrogen rich mixture which is the syngas feed for the ammonia production. The SCRR system will displace natural gas presently used in the fossil reformer combustion chamber.

  3. Wideband CMOS receivers

    CERN Document Server

    Oliveira, Luis

    2015-01-01

    This book demonstrates how to design a wideband receiver operating in current mode, in which the noise and non-linearity are reduced, implemented in a low cost single chip, using standard CMOS technology.  The authors present a solution to remove the transimpedance amplifier (TIA) block and connect directly the mixer’s output to a passive second-order continuous-time Σ∆ analog to digital converter (ADC), which operates in current-mode. These techniques enable the reduction of area, power consumption, and cost in modern CMOS receivers.

  4. Solar Pilot Plant, Phase I. Preliminary design report. Volume IV. Receiver subsystem (CDRL item 2). [Contains engineering drawings

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-05-01

    The Honeywell receiver subsystem design uses well established fossil technology and consists of a cavity receiver housing, a steam generator, a cavity barrier, piping, and a support tower. The steam generator absorbs the redirected solar energy from the collector subsystem and converts it to superheated steam which drives the turbine. The receiver is adequately shielded to protect personnel and equipment. A cavity barrier is lowered at night to conserve heat and expedite startup the following day. This volume contains the subsystem design and methodology and the correlation with the design and performance characteristics of the SRE steam generator which was fabricated and successfully tested during the program.

  5. Temperature stabilization of optofluidic photonic crystal cavities

    DEFF Research Database (Denmark)

    Kamutsch, Christian; Smith, Cameron L.C.; Graham, Alexandra

    2009-01-01

    demonstrate a PhC cavity with a quality factor of Q15 000 that exhibits a temperature-independent resonance. Temperature-stable cavities constitute a major building block in the development of a large suite of applications from high-sensitivity sensor systems for chemical and biomedical applications...

  6. Tooth structure and fracture strength of cavities

    DEFF Research Database (Denmark)

    Mondelli, José; Sene, Fábio; Ramos, Renata Pereira

    2007-01-01

    This study evaluated, in vitro, the loss of tooth substance after cavity preparation for direct and indirect restorations and its relationship with fracture strength of the prepared teeth. Sixty sound human maxillary first premolars were assigned to 6 groups (n=10). MOD direct composite cavities...

  7. Superconducting rf cavities for accelerator application

    International Nuclear Information System (INIS)

    Proch, D.

    1988-01-01

    The subject of this paper is a review of superconducting cavities for accelerator application (β = 1). The layout of a typical accelerating unit is described and important parameters are discussed. Recent cavity measurements and storage ring beam tests are reported and the present state of the art is summarized

  8. Telescopic Examination of the mastoid Cavity

    OpenAIRE

    Bhandari, Anita; Sharma, Man Prakash; Bapna, A. S.

    1998-01-01

    Otoendoscopy enables viewing of different angles of the tympanomastoid area and approach to them for better prognosis. A comparative study of post-operative mastoid cavities has been done using the Hopkin’s rod telescope, Otoscope and microscope. Various procedures have also been done successfully on the mastoid cavity using the telescope on an outdoor basis.

  9. Toroidal 12 cavity klystron : a novel approach

    International Nuclear Information System (INIS)

    Hazarika, A.B.R.

    2013-01-01

    A toroidal 12 cavity klystron is designed to provide with high energy power with the high frequency microwave RF- plasma generated from it. The cavities are positioned in clock hour positions. The theoretical modeling and designing is done to study the novel approach. (author)

  10. Prototype storage cavity for LEP accelerating RF

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    The principle of an RF storage cavity was demonstrated with this prototype, working at 500 MHz. The final storage cavities were larger, to suit the LEP accelerating frequency of 352.2 MHz. Cu-tubes for watercooling are brazed onto the upper half, the lower half is to follow. See also 8006061, 8109346, 8407619X, and Annual Report 1980, p.115.

  11. The gastro-oesophageal common cavity revisited

    NARCIS (Netherlands)

    Aanen, M. C.; Bredenoord, A. J.; Samsom, M.; Smout, A. J. P. M.

    2006-01-01

    The manometric common cavity phenomenon has been used as indicator of gastro-oesophageal reflux of liquid or gaseous substances. Using combined pH and impedance recording as reference standard the value of a common cavity as indicator of gastro-oesophageal reflux was tested. Ten healthy male

  12. Geometric Model of a Coronal Cavity

    Science.gov (United States)

    Kucera, Therese A.; Gibson, S. E.; Ratawicki, D.; Dove, J.; deToma, G.; Hao, J.; Hudson, H. S.; Marque, C.; McIntosh, P. S.; Reeves, K. K.; hide

    2010-01-01

    We observed a coronal cavity from August 8-18 2007 during a multi-instrument observing campaign organized under the auspices of the International Heliophysical Year (IHY). Here we present initial efforts to model the cavity with a geometrical streamer-cavity model. The model is based the white-light streamer mode] of Gibson et a]. (2003 ), which has been enhanced by the addition of a cavity and the capability to model EUV and X-ray emission. The cavity is modeled with an elliptical cross-section and Gaussian fall-off in length and width inside the streamer. Density and temperature can be varied in the streamer and cavity and constrained via comparison with data. Although this model is purely morphological, it allows for three-dimensional, multi-temperature analysis and characterization of the data, which can then provide constraints for future physical modeling. Initial comparisons to STEREO/EUVI images of the cavity and streamer show that the model can provide a good fit to the data. This work is part of the effort of the International Space Science Institute International Team on Prominence Cavities

  13. Dissipative preparation of entanglement in optical cavities

    DEFF Research Database (Denmark)

    Kastoryano, Michael James; Reiter, Florentin; Sørensen, Anders Søndberg

    2011-01-01

    We propose a novel scheme for the preparation of a maximally entangled state of two atoms in an optical cavity. Starting from an arbitrary initial state, a singlet state is prepared as the unique fixed point of a dissipative quantum dynamical process. In our scheme, cavity decay is no longer...

  14. Inertial confinement fusion reactor cavity phenomena

    International Nuclear Information System (INIS)

    Bohachevsky, I.O.; Hafer, J.F.; Devaney, J.J.; Pendergrass, J.H.

    1978-01-01

    Cavity phenomena in Inertial Confinement Fusion (ICF) are created by the interaction of energy released by the fuel pellet microexplosion with the medium inside the reactor cavity. The ambient state of the medium in ICF reactor cavities is restricted primarily by its effects on laser beam propagation and on the fuel pellet trajectory. Therefore, a relatively wide choice of ambient conditions can be exploited to gain first-wall protection and advantages in energy extraction. Depending on the choice of ambient cavity conditions and on fuel pellet design, a variety of physical phenomena may develop and dominate the ICF reactor cavity design. Because of the cavity phenomena, the forms of energy released by the fuel-pellet microexplosion are modified before reaching the first wall, thus giving rise to different cavity design problems. The types of cavity phenomena encountered in the conceptual design of ICF reactors are examined, the approaches available for their modeling and analysis are discussed, and some results are presented. Most phenomena are sufficiently well understood to permit valid engineering assessments of the proposed ICF reactor concepts

  15. Tooth structure and fracture strength of cavities

    DEFF Research Database (Denmark)

    Mondelli, José; Sene, Fábio; Ramos, Renata Pereira

    2007-01-01

    This study evaluated, in vitro, the loss of tooth substance after cavity preparation for direct and indirect restorations and its relationship with fracture strength of the prepared teeth. Sixty sound human maxillary first premolars were assigned to 6 groups (n=10). MOD direct composite cavities......) or 1/2 (Groups III and VI) of the intercuspal distance. Teeth were weighed (digital balance accurate to 0.001 g) before and after preparation to record tooth substance mass lost during cavity preparation. The prepared teeth were submitted to occlusal loading to determine their fracture strength using...... a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed by two-way ANOVA and Tukey test (alpha= 0.05). 1/4-inlay cavities had higher percent mean mass loss (9.71%) than composite resin cavities with the same width (7.07%). 1/3-inlay preparations also produced higher percent mean...

  16. Fiber cavities with integrated mode matching optics.

    Science.gov (United States)

    Gulati, Gurpreet Kaur; Takahashi, Hiroki; Podoliak, Nina; Horak, Peter; Keller, Matthias

    2017-07-17

    In fiber based Fabry-Pérot Cavities (FFPCs), limited spatial mode matching between the cavity mode and input/output modes has been the main hindrance for many applications. We have demonstrated a versatile mode matching method for FFPCs. Our novel design employs an assembly of a graded-index and large core multimode fiber directly spliced to a single mode fiber. This all-fiber assembly transforms the propagating mode of the single mode fiber to match with the mode of a FFPC. As a result, we have measured a mode matching of 90% for a cavity length of ~400 μm. This is a significant improvement compared to conventional FFPCs coupled with just a single mode fiber, especially at long cavity lengths. Adjusting the parameters of the assembly, the fundamental cavity mode can be matched with the mode of almost any single mode fiber, making this approach highly versatile and integrable.

  17. Statistics of magnetoconductance in ballistic cavities

    International Nuclear Information System (INIS)

    Yang, X.; Ishio, H.; Burgdoerfer, J.

    1995-01-01

    The statistical properties of magnetoconductance in ballistic microcavities are investigated numerically. The distribution of conductance for chaotic cavities is found to follow the renormalized Porter-Thomas distribution suggested by random-matrix theory for the Gaussian ensemble while the conductance distribution of regular cavities in magnetic fields is nonuniversal and shifted towards the maximum value for a given number of open channels. The renormalized Porter-Thomas distribution implies a universal dependence of fluctuation amplitude on the mean conductance for chaotic cavities in the absence of time-reversal symmetry. The fluctuation amplitude for regular cavities is found to be larger than the saturation value of the fluctuation amplitude of chaotic cavities predicted by random-matrix theory. The change of the mean conductance as a function of the external magnetic field is consistent with semiclassical predictions

  18. New achievements in RF cavity manufacturing

    International Nuclear Information System (INIS)

    Lippmann, G.; Pimiskern, K.; Kaiser, H.

    1993-01-01

    Dornier has been engaged in development, manufacturing and testing of Cu-, Cu/Nb- and Nb-cavities for many years. Recently, several different types of RF cavities were manufactured. A prototype superconducting (s.c.) B-Factory accelerating cavity (1-cell, 500 MHz) was delivered to Cornell University, Laboratory of Nuclear Studies. A second lot of 6 s.c. cavities (20-cell, 3000 MHz) was fabricated on contract from Technical University of Darmstadt for the S-DALINAC facility. Finally, the first copper RF structures (9-cell, 1300 MHz) for TESLA were finished and delivered to DESY, two s.c. niobium structures of the same design are in production. Highlights from the manufacturing processes of these cavities are described and first performance results will be reported

  19. Sender-Receiver Games

    NARCIS (Netherlands)

    Peeters, R.J.A.P.; Potters, J.A.M.

    1999-01-01

    Standard game-theoretic solution concepts do not guarantee meaningful commu- nication in cheap-talk games. In this paper, we define a solution concept which guarantees communication for a large class of games by designing a behavior pro- tocol which the receiver uses to judge messages sent by the

  20. Luminescent photonic crystal cavities for fiber-optic sensors, coupled dissimilar cavities and optofluidics

    Science.gov (United States)

    Dündar, Mehmet A.; Wang, Bowen; Siahaan, Timothy; Voorbraak, Joost A. M.; Speijcken, Noud W. L.; Nötzel, Richard; van der Hoek, Marinus J.; He, Sailing; Fiore, Andrea; Van der Heijden, Rob W.

    2012-06-01

    Photonic crystal (PhC) cavities made in broadband luminescent material offer attractive possibilities for flexible active devices. The luminescence enables the cavity to operate as an autonomous entity. New applications of this property are demonstrated for cavities made in the InGaAsP underetched semiconductor membrane with embedded InAs Quantum Dots that emit in the range of 1400-1600 nm. Planar photonic crystal membrane nanocavities were released from the parent chip by mechanical nanomanipulation. The released cavity particle could be bonded on an arbitrary surface, which was exploited to make a novel fiber-optic tip sensor with a PhC cavity attached to the tip. A single mode from a short cavity is shown to couple simultaneously to at least three cavity modes of a long cavity, as concluded from level anticrossing data when the small cavity was photothermally tuned. Reconfigurable and movable cavities were created by locally varying the infiltration status by liquid oil near a PhC waveguide or defect cavity. Liquid was displaced locally on a micron scale using capillary force effects or laser-induced evaporation and condensation phenomena.

  1. Cavity solitons and localized patterns in a finite-size optical cavity

    Energy Technology Data Exchange (ETDEWEB)

    Kozyreff, G. [Optique Nonlineaire Theorique, Universite Libre de Bruxelles (U.L.B.), CP 231 (Belgium); Gelens, L. [Applied Physics Research Group (APHY), Vrije Universiteit Brussel (Belgium)

    2011-08-15

    In appropriate ranges of parameters, laser-driven nonlinear optical cavities can support a wide variety of optical patterns, which could be used to carry information. The intensity peaks appearing in these patterns are called cavity solitons and are individually addressable. Using the Lugiato-Lefever equation to model a perfectly homogeneous cavity, we show that cavity solitons can only be located at discrete points and at a minimal distance from the edges. Other localized states which are attached to the edges are identified. By interpreting these patterns in an information coding frame, the information capacity of this dynamical system is evaluated. The results are explained analytically in terms of the the tail characteristics of the cavity solitons. Finally, the influence of boundaries and of cavity imperfections on cavity solitons are compared.

  2. Mucoceles of the oral cavity in pediatric patients

    Directory of Open Access Journals (Sweden)

    Chung Wei Wu

    2011-07-01

    Full Text Available Mucoceles are quite common in the oral cavity, but reports on pediatric patients are very rare. The aims of this study were to present our data and experience in the treatment of mucoceles of the oral cavity in pediatric patients, to compare them with those of other countries, and to remind the pediatric physician to devote much attention to lesions of the oral cavity in children. This retrospective study is based on the record of the patients who received surgical treatment for mucoceles of the oral cavity with pathologic confirmation at the Department of Dentistry, Kaohsiung Medical University Hospital, Taiwan, between 2000 and 2004. Patients younger than 18 years were included in this study. The analyzed data included age, gender, site, size, histopathologic findings, surgical methods, and complications. There were a total of 289 patients with mucoceles confirmed by histopathologic examination. As many as 64 patients were younger than 18 years. Of the 64, 34 were girls and 30 were boys; 89.1% of the lesions were in the lower lip; and 48.4% of the lesions were less than 5 mm in diameter. Histopathologic findings showed that all mucoceles were of the extravasation type. As many as 30 patients were treated by carbon dioxide laser vaporization, and two cases recurred (6.67%; 34 patients were treated by surgical excision, and the recurrence rate (5.88% was not statistically different for the treatment methods. The laser vaporization has the advantage of less bleeding, no sutures, and saving time, especially suitable for children with oral mucocele.

  3. Cancer of the oral cavity

    International Nuclear Information System (INIS)

    Wang, C.C.

    1987-01-01

    Squamous cell carcinomas of the oral cavity are curable. When early tumor (T1 and T2) is diagnosed and treated, cure rates by surgery or irradiation are high. The choice of therapeutic modalities for these lesions is complex and depends on the site of origin and size of the tumor, the presence or absence of nodal metastases, and the age, physical, medical, and socioeconomic status of the patient. Other factors include the willingness of the patient to return for a protracted course of radiation therapy, the skill of the physician, and the relative morbidity and cosmesis of the two forms of treatment. In general, surgery may be considered for early (T1) lesions if the deformity resulting from surgery is minimal. If resection involves major morbidity, such as a deformity that alters cosmesis or the function of the speech and swallowing mechanisms, then radiation therapy is preferred. For medium-sized (T2) tumors, superficial radiation therapy is the treatment of choice, for it controls the disease and preserves normal function and anatomy. Surgery is reserved for radiation failures. Extensive disease (T3 and T4) often associated with bone and muscle involvement and cervical lymph node metastases is rarely curable by radiation therapy or surgery alone; a combined approach using radiation therapy and surgery is therefore the procedure of choice

  4. LEP superconducting accelerating cavity module

    CERN Multimedia

    1995-01-01

    With its 27-kilometre circumference, the Large Electron-Positron (LEP) collider was the largest electron-positron accelerator ever built. The excavation of the LEP tunnel was Europe’s largest civil-engineering project prior to the Channel Tunnel. Three tunnel-boring machines started excavating the tunnel in February 1985 and the ring was completed three years later. In its first phase of operation, LEP consisted of 5176 magnets and 128 accelerating cavities. CERN’s accelerator complex provided the particles and four enormous detectors, ALEPH, DELPHI, L3 and OPAL, observed the collisions. LEP was commissioned in July 1989 and the first beam circulated in the collider on 14 July. The collider's initial energy was chosen to be around 91 GeV, so that Z bosons could be produced. The Z boson and its charged partner the W boson, both discovered at CERN in 1983, are responsible for the weak force, which drives the Sun, for example. Observing the creation and decay of the short-lived Z boson was a critical test of...

  5. The MEDICI reactor cavity model

    International Nuclear Information System (INIS)

    Bergeron, K.D.; Trebikock, W.

    1983-01-01

    The MEDICI reactor cavity model is currently under development with the goal of providing a flexible, relatively realistic treatment of ex-vessel severe accident phenomena suitable for large system codes like CONTAIN and MELCOR. The code is being developed with an emphasis on top-down design, to facilitate adaptability and multiple applications. A brief description of the overall code structure is provided. One of the key new models is then described in more detail. This is a dynamic quench model for debris beds. An example calculation using this model is presented. The question of whether it is necessary to consider the simultaneous motion of the quench front and ablation of the concrete is addressed with some scoping models. It is found that for realistic parameters and coolable beds, concrete ablation is too slow a process to be important on the quenching time scale. Remelt in the dry zone, however, is found to be potentially important on this time scale, so quench and remelt are considered simultaneously

  6. Hydroforming of Tesla Cavities at Desy

    International Nuclear Information System (INIS)

    Singer, W.; Kaiser, H.; Singer, X.; Gonin, I.; Zhelezov, I.; Khabibullin, T.; Kneisel, P.; Saito, K.

    2000-01-01

    Since several years the development of seamless niobium cavity fabrication by hydro forming is being pursued at DESY. This technique offers the possibility of lower cost of fabrication and perhaps better rf performance of the cavities because of the elimination of electron-beam welds, which in the standard fabrication technique have sometimes lead to inferior cavity performance due to defects. Several single cell 1300 MHz cavities have been formed from high purity seamless niobium tubes, which are under computer control expanded with internal pressure while simultaneously being swaged axially. The seamless tubes have been made by either back extrusion and flow forming or by spinning or deep drawing. Standard surface treatment techniques such as high temperature post purification, buffered chemical polishing (BCP), electropolishing (EP) and high pressure ultra pure water rinsing (HPR) have been applied to these cavities. The cavities exhibited high Q - values of 2 x 10 10 at 2K and residual resistances as low as 3 n(Omega) after the removal of a surface layer of app. 100 (micro)m by BCP. Surprisingly, even at high gradients up to the maximum measured values of E acc ∼ 33 MV/m the Q-value did not decrease in the absence of field emission as often observed. After electropolishing of additional 100 (micro)m one of the cavities reached an accelerating gradient of E acc (ge) 42 MV/m

  7. Preparation and handling of superconducting RF cavities

    International Nuclear Information System (INIS)

    Furuya, Takaaki

    1990-01-01

    The present paper outlines the recent preparation methods for superconducting cavities used in various laboratories and universities, and reports the problems of the cavity fabrication at KEK as an example of mass production. Preparation and handling are first addressed, focusing on material, fabrication, surface treatment, rinsing, clean environment, and heat treatment. Cavity production at KEK is then described, centering on defects on the surface and clean environments. Field gradients of more than 20 MV/m have been obtained by 1.5-3 GHz single cavities, for multi-cell cavities Eacc of 10 MV/m are available at any frequency range. The successful construction of thirty-two cavities for TRISTAN at KEK is due to the careful checking of the surface and quality control of all processes against the surface defects and contaminations. Eacc of 5 MV/m has been achieved by 94 % of the TRISTAN cavities at the first cold test, but 6 % of them had to be reworked because of the surface defects. These defects could not be detected by an X-ray photograph or visual inspections during the fabrication processes. (N.K.)

  8. Passive control of supersonic cavity flowfields

    Science.gov (United States)

    Chokani, N.; Kim, I.

    1991-01-01

    A computational investigation has been conducted to study the effect and mechanisms of the passive control of a supersonic flow over a rectangular two-dimensional cavity. The passive control was included through the use of a porous surface over a vent chamber in the floor of the cavity. The passive control effectively suppressed the low-frequency pressure oscillations for the open type cavity, (length-to-depth ratio = 6.0). The mechanism for the suppression was observed to be the stabilization of the motion of the free shear layer. For the closed type cavity flow, (length-to-depth ratio = 17.5), the passive control modified the flowfield to nearly that of an open type cavity flow; further the cavity drag was reduced by a factor of four. The computational results of both cases showed good agreement with the available experimental data and the predictions of a semiempirical formula. This study demonstrates that the passive control concept can be used to improve the aerodynamic characteristics of open and closed cavity flowfields.

  9. The CEBAF separator cavity resonance control system

    International Nuclear Information System (INIS)

    M. Wissmann; C. Hovater; A. Guerra; T. Plawski

    2005-01-01

    The CEBAF energy upgrade will increase the maximum beam energy from 6 GeV to 12 GeV available to the experimental halls. RF deflection cavities (separators) are used to direct the electron beam to the three halls. The resulting increase in RF separator cavity gradient and subsequent increase in RF power needed for these higher energies will require the cavities to have active resonance control. Currently, at the present 4 to 6 GeV energies, the cavities are tuned mechanically and then stabilized with Low Conductivity Water (LCW) which is maintained at a constant temperature of 95 Fahrenheit. This approach is no longer feasible and an active resonance control system that controls both water temperature and flow has been designed and built. The system uses a commercial PLC with embedded PID controls to regulate water temperature and flow to the cavities. The system allows the operator to remotely adjust temperature/flow and consequently cavity resonance for the full range of beam energies. Ultimately, closed loop control will be maintained by monitoring each cavity's reflected power. This paper describes this system

  10. Forward Modeling of a Coronal Cavity

    Science.gov (United States)

    Kucera, T. A.; Gibson, S. E.; Schmit, D. J.

    2011-01-01

    We apply a forward model of emission from a coronal cavity in an effort to determine the temperature and density distribution in the cavity. Coronal cavities are long, low-density structures located over filament neutral lines and are often seen as dark elliptical features at the solar limb in white light, EUV and X-rays. When these structures erupt they form the cavity portions of CMEs The model consists of a coronal streamer model with a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel length. Temperature and density can be varied as a function of altitude both in the cavity and streamer. We apply this model to a cavity observed in Aug. 2007 by a wide array of instruments including Hinode/EIS, STEREO/EUVI and SOHO/EIT. Studies such as these will ultimately help us understand the the original structures which erupt to become CMEs and ICMES, one of the prime Solar Orbiter objectives.

  11. Superconducting cavity driving with FPGA controller

    Energy Technology Data Exchange (ETDEWEB)

    Czarski, T.; Koprek, W.; Pozniak, K.T.; Romaniuk, R.S. [Warsaw Univ. of Technology (Poland); Simrock, S.; Brand, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Chase, B.; Carcagno, R.; Cancelo, G. [Fermi National Accelerator Lab., Batavia, IL (United States); Koeth, T.W. [Rutgers - the State Univ. of New Jersey, NJ (United States)

    2006-07-01

    The digital control of several superconducting cavities for a linear accelerator is presented. The laboratory setup of the CHECHIA cavity and ACC1 module of the VU-FEL TTF in DESY-Hamburg have both been driven by a Field Programmable Gate Array (FPGA) based system. Additionally, a single 9-cell TESLA Superconducting cavity of the FNPL Photo Injector at FERMILAB has been remotely controlled from WUT-ISE laboratory with the support of the DESY team using the same FPGA control system. These experiments focused attention on the general recognition of the cavity features and projected control methods. An electrical model of the resonator was taken as a starting point. Calibration of the signal path is considered key in preparation for the efficient driving of a cavity. Identification of the resonator parameters has been proven to be a successful approach in achieving required performance; i.e. driving on resonance during filling and field stabilization during flattop time while requiring reasonable levels of power consumption. Feed-forward and feedback modes were successfully applied in operating the cavities. Representative results of the experiments are presented for different levels of the cavity field gradient. (orig.)

  12. Design of the Advanced LIGO recycling cavities.

    Science.gov (United States)

    Arain, Muzammil A; Mueller, Guido

    2008-07-07

    The current LIGO detectors will undergo an upgrade which is expected to improve their sensitivity and bandwidth significantly. These advanced gravitational-wave detectors will employ stable recycling cavities to better confine their spatial eigenmodes instead of the currently installed marginally stable power recycling cavity. In this letter we describe the general layout of the recycling cavities and give specific values for a first possible design. We also address the issue of mode mismatch due to manufacturing tolerance of optical elements and present a passive compensation scheme based upon optimizing the distances between optical elements.

  13. Interaction of IREB with a cavity

    International Nuclear Information System (INIS)

    Sawhney, R.; Mishra, Mamta; Purkayastha, A.D.; Rambabu, P.; Maheshwari, K.P.

    1991-01-01

    The propagation of an intense pulsed relativistic electron beam (IREB) through a cavity resonator is considered. The cavity gets shock excited. The electromagnetic fields so generated interact with the beam in such a way that the energy is transferred from the front of the beam to the back. As a result the beams gets energized but shortened in time. Analysis for the chosen dominant mode of the cavity viz. TMsub(010) is carried out. The induced electric field excited is calculated and the accelerating potential is estimated. The results are compared with the recent-experiments. (author). 5 refs., 1 fig

  14. Micro-Cavity Fluidic Dye Laser

    DEFF Research Database (Denmark)

    Helbo, Bjarne; Kristensen, Anders; Menon, Aric Kumaran

    2003-01-01

    We have successfully designed, fabricated and characterized a micro-cavity fluidic dye laser with metallic mirrors, which can be integrated with polymer based lab-on-a-chip microsystems without further processing steps. A simple rate-equation model is used to predict the average pumping power...... threshold for lasing as function of cavity-mirror reflectance, laser dye concentration and cavity length. The laser device is characterized using the laser dye Rhodamine 6G dissolved in ethanol. Lasing is observed, and the influence of dye concentration is investigated....

  15. Indirect coupling of magnons by cavity photons

    Science.gov (United States)

    Zare Rameshti, Babak; Bauer, Gerrit E. W.

    2018-01-01

    The interaction between two magnetic spheres in microwave cavities is studied by Mie scattering theory beyond the magnetostatic and rotating wave approximations. We demonstrate that two spatially separated dielectric and magnetic spheres can be strongly coupled over a long distance by the electric field component of standing microwave cavity modes. The interactions split acoustical (dark) and optical (bright) modes in a way that can be mapped on a molecular orbital theory of the hydrogen molecule. Breaking the symmetry by assigning different radii to the two spheres introduces "ionic" character to the magnonic bonds. These results illustrate the coherent and controlled energy exchange between objects in microwave cavities.

  16. Analysis of dual coupler nested coupled cavities.

    Science.gov (United States)

    Adib, George A; Sabry, Yasser M; Khalil, Diaa

    2017-12-01

    Coupled ring resonators are now forming the basic building blocks in several optical systems serving different applications. In many of these applications, a small full width at half maximum is required, along with a large free spectral range. In this work, a configuration of passive coupled cavities constituting dual coupler nested cavities is proposed. A theoretical study of the configuration is presented allowing us to obtain analytical expressions of its different spectral characteristics. The transfer function of the configuration is also used to generate design curves while comparing these results with analytical expressions. Finally, the configuration is compared with other coupled cavity configurations.

  17. Cavity Pressure Behaviour in Micro Injection Moulding

    DEFF Research Database (Denmark)

    Griffiths, C.A.; Dimov, S.S.; Scholz, S.

    2010-01-01

    Process monitoring of micro injection moulding (µIM) is of crusial importance to analyse the effect of different parameter settings on the process and to assess its quality. Quality factors related to cavity pressure can provide useful information directly connected with the dyanmics of the process...... as well as with the filling of the cavity by the polymer melt. In this paper, two parameters derived from cavity pressure over time (i.e. pressure work). The influence of four µIM parameters (melt temperature, mould temperature, injection speed, aand packing pressure) on the two pressure-related outputs...

  18. Upgraded cavities for the positron accumulator ring of the APS

    International Nuclear Information System (INIS)

    Kang, Y.W.; Jiang, X.; Mangra, D.

    1997-01-01

    Upgraded versions of cavities for the APS positron accumulator ring (PAR) have been built and are being tested. Two cavities are in the PAR: a fundamental 9.8-MHz cavity and a twelfth harmonic 117.3-MHz cavity. Both cavities have been manufactured for higher voltage operation with improved Q-factors, reliability, and tuning capability. Both cavities employ current-controlled ferrite tuners for control of the resonant frequency. The harmonic cavity can be operated in either a pulsed mode or a CW mode. The rf properties of the cavities are presented

  19. Ultra-wideband receiver

    Science.gov (United States)

    McEwan, Thomas E.

    1994-01-01

    An ultra-wideband (UWB) receiver utilizes a strobed input line with a sampler connected to an amplifier. In a differential configuration, .+-.UWB inputs are connected to separate antennas or to two halves of a dipole antenna. The two input lines include samplers which are commonly strobed by a gating pulse with a very low duty cycle. In a single ended configuration, only a single strobed input line and sampler is utilized. The samplers integrate, or average, up to 10,000 pulses to achieve high sensitivity and good rejection of uncorrelated signals.

  20. Nanohybrid vs. fine hybrid composite in extended Class II cavities after six years

    NARCIS (Netherlands)

    Krämer, N.; García-Godoy, F.; Reinelt, C.; Feilzer, A.J.; Frankenberger, R.

    2011-01-01

    Objectives In a controlled prospective split-mouth study, clinical behavior of two different resin composites in extended Class II cavities was observed over six years. Methods Thirty patients received 68 direct resin composite restorations (Solobond M + Grandio: n = 36; Syntac + Tetric Ceram: n =

  1. Fabrication, Treatment and Testing of a 1.6 Cell Photo-injector Cavity for HZB

    Energy Technology Data Exchange (ETDEWEB)

    P. Kneisel, T. Kamps, J. Knobloch, O. Kugeler, A. Neumann, R. Nietubyc, J.K. Sekutowicz

    2011-03-01

    As part of a CRADA (Cooperative Research and Development Agreement) between Forschungszentrum Dresden (FZD) and JLab we have fabricated and tested after appropriate surface treatment a 1.5 cell, 1300 MHz RRR niobium photo-injector cavity to be used in a demonstration test at BESSY*. Following a baseline test at JLab, the cavity received a lead spot coating of ~8 mm diameter deposited with a cathode arc at the Soltan Institute on the endplate made from large grain niobium. It had been demonstrated in earlier tests with a DESY built 1.5 cell cavity the original design that a lead spot of this size can be a good electron source, when irradiated with a laser light of 213 nm . In the initial test with the lead spot we could measure a peak surface electric field of ~ 29 MV/m; after a second surface treatment, carried out to improve the cavity performance, but which was not done with sufficient precaution, the lead spot was destroyed and the cavity had to be coated a second time. This contribution reports about the experiences and results obtained with this cavity.

  2. High-Q ferrite-tuned cavity

    International Nuclear Information System (INIS)

    Carlini, R.D.; Thiessen, H.A.; Potter, J.M.; Earley, L.M.

    1983-01-01

    Rapid cycling proton synchrotrons, such as the proposed LAMPF II accelerator, require approximately 10 MV per turn rf with 17% tuning range near 50 MHz. The traditional approach to ferrite-tuned cavities uses a ferrite which is longitudinally biased (rf magnetic field parallel to bias field). This method leads to unacceptably high losses in the ferrite. At Los Alamos, we are developing a cavity with transverse bias (rf magnetic field perpendicular to the bias field) that makes use of the tensor permeability of the ferrite. Initial tests of a small (10-cm-diam) quarter-wave singly re-entrant cavity tuned by several different ferrites indicate that the losses in the ferrite can be made negligible compared with the losses due to the surface resistivity of the copper cavity

  3. Molding of L band niobium superconductor cavity

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Hitoshi; Funahashi, Yoshisato; Saito, Kenji; Noguchi, Shuichi; Koizumi, Susumu [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1995-07-01

    A cavity to produce high accelerating electron field was developed. The L-band (1.3 GHz) niobium superconductor unit cell cavity was ellipsoid with {phi}217.3 mm outer diameter and 2.5 mm thickness and consisted of two pieces of half cell, two beam pipes and flange. A deep drawing process was adapted. In spite of the first trial manufacture, each good cavity was obtained. Characteristic properties of niobium materials, molding method of cavity, extension of sheet after molding, production of beam pipe, accuracy and the cost were explained. Niobium materials. showed tensile strength 15.6 kg/mm{sup 2}, load-carrying capacity 4.1 kg/mm{sup 2}, density 8.57, extension 42.5% and RRR (resistance residual ratio){>=}200. (S.Y.)

  4. section of an accelerating cavity from LEP

    CERN Multimedia

    This is a section of an accelerating cavity from LEP, cut in half to show the layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities are now used in LEP to double the energy of the particle beams.

  5. Degreasing and cleaning superconducting RF Niobium cavities

    Energy Technology Data Exchange (ETDEWEB)

    Rauchmiller, Michael; Kellett, Ron; /Fermilab

    2011-09-01

    The purpose and scope of this report is to detail the steps necessary for degreasing and cleaning of superconducting RF Niobium cavities in the A0 clean room. It lists the required equipment and the cleaning procedure.

  6. Circuit QED with 3D cavities

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Edwar; Baust, Alexander; Zhong, Ling; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany); Anderson, Gustav; Wang, Lujun; Eder, Peter; Fischer, Michael; Goetz, Jan; Haeberlein, Max; Schwarz, Manuel; Wulschner, Karl Friedrich; Deppe, Frank; Fedorov, Kirill; Huebl, Hans; Menzel, Edwin [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Marx, Achim [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany)

    2015-07-01

    In typical circuit QED systems on-chip superconducting qubits are coupled to integrated coplanar microwave resonators. Due to the planar geometry, the resonators are often a limiting factor regarding the total coherence of the system. Alternatively, similar hybrid systems can be realized using 3D microwave cavities. Here, we present design considerations for the 3D microwave cavity as well as the superconducting transmon qubit. Moreover, we show experimental data of a high purity aluminum cavity demonstrating quality factors above 1.4 .10{sup 6} at the single photon level and a temperature of 50 mK. Our experiments also demonstrate that the quality factor is less dependent on the power compared to planar resonator geometries. Furthermore, we present strategies for tuning both the cavity and the qubit individually.

  7. Cavity-Enhanced Transport of Charge

    Science.gov (United States)

    Hagenmüller, David; Schachenmayer, Johannes; Schütz, Stefan; Genes, Claudiu; Pupillo, Guido

    2017-12-01

    We theoretically investigate charge transport through electronic bands of a mesoscopic one-dimensional system, where interband transitions are coupled to a confined cavity mode, initially prepared close to its vacuum. This coupling leads to light-matter hybridization where the dressed fermionic bands interact via absorption and emission of dressed cavity photons. Using a self-consistent nonequilibrium Green's function method, we compute electronic transmissions and cavity photon spectra and demonstrate how light-matter coupling can lead to an enhancement of charge conductivity in the steady state. We find that depending on cavity loss rate, electronic bandwidth, and coupling strength, the dynamics involves either an individual or a collective response of Bloch states, and we explain how this affects the current enhancement. We show that the charge conductivity enhancement can reach orders of magnitudes under experimentally relevant conditions.

  8. Cavity squeezing by a quantum conductor

    International Nuclear Information System (INIS)

    Mendes, Udson C; Mora, Christophe

    2015-01-01

    Hybrid architectures integrating mesoscopic electronic conductors with resonant microwave cavities have a great potential for investigating unexplored regimes of electron–photon coupling. In this context, producing nonclassical squeezed light is a key step towards quantum communication with scalable solid-state devices. Here we show that parametric driving of the electronic conductor induces a squeezed steady state in the cavity. We find that squeezing properties of the cavity are essentially determined by the electronic noise correlators of the quantum conductor. In the case of a tunnel junction, we predict that squeezing is optimized by applying a time-periodic series of quantized δ—peaks in the bias voltage. For an asymmetric quantum dot, we show that a sharp Leviton pulse is able to achieve perfect cavity squeezing. (paper)

  9. Design of an optical cavity for gravimetry

    Science.gov (United States)

    Billion Reyes, M. S.; Lopez-Vazquez, A.; Pimenta, W. M.; Gonzalez, M. A.; Franco-Villafane, J. A.; Gomez, E.

    2017-04-01

    Atomic interferometry is a widely used method to perform precision measurements of accelerations. We enhance the interferometric signal by adding an optical cavity around the free-falling atoms inside of a vacuum chamber. We use a bow-tie configuration to support a traveling wave and avoid spatial fluctuations in the light shift. To induce collective behavior (entangled state), we design the optical cavity with a cooperativity factor higher than one. We present the characterization of an optical cavity with a maximized beam waist to reach homogeneous illumination of the atomic cloud. The mirrors have high reflectivity (R =99.999%) at 780 nm, in a non-confocal arrangement so that we can excite transverse modes independently or simultaneously. We describe our progress to achieve a transverse mode closer to a flat-top and a cavity design that fits our geometrical restrictions. Funding from CONACYT.

  10. Mechanical design and fabrication of power feed cavity test setup

    International Nuclear Information System (INIS)

    Ghodke, S.R.; Dhavle, A.S.; Sharma, Vijay; Sarkar, Shreya; Kumar, Mahendra; Nayak, Susanta; Barnwal, Rajesh; Jayaprakash, D.; Mondal, J.; Nimje, V.T.; Mittal, K.C.; Gantayet, L.M.

    2013-01-01

    Power feed cavity set up consists of nine number of accelerating cavity and eight numbers of coupling cavity for testing of power feed cavity with coupling flange for 2856 MHz S band standing wave coupled cavity linac. When we are assembling the cavity and applying the pressure, its resonance frequency changes with applied pressure/load. After some critical pressure/load frequency change becomes negligible or zero. This set up will be used to find out assembly performance of power feed cavity and its coupler. Top four cavity or eight half cells as well as bottom four cavity or eight half cells will be brazed separately. Power feed cavity will be sandwiched between this two brazed cavity assemblies. This paper discuss about linear motion bush, linear motion rod, load cell, hydraulic actuator, power pack, stepper motor PLC control, jig boring, alignment, tolerances and assembly procedure for this test setup. (author)

  11. HOM power in FCC-ee cavities

    CERN Document Server

    Karpov, Ivan; Chapochnikova, Elena

    2018-01-01

    This Note summarizes the results of the power loss calculations for FCC-ee machines with 400.79 MHz cavity options. The requirements for the single-cell cavity design and for the operation with beam are obtained from the results for the high-current FCC-ee machine (Z). For other machines the power loss is sufficiently low and can be absorbed and extracted by foreseen HOM couplers.

  12. Cavity-Assisted Quantum Bath Engineering

    Science.gov (United States)

    Murch, K. W.; Vool, U.; Zhou, D.; Weber, S. J.; Girvin, S. M.; Siddiqi, I.

    2012-11-01

    We demonstrate quantum bath engineering for a superconducting artificial atom coupled to a microwave cavity. By tailoring the spectrum of microwave photon shot noise in the cavity, we create a dissipative environment that autonomously relaxes the atom to an arbitrarily specified coherent superposition of the ground and excited states. In the presence of background thermal excitations, this mechanism increases state purity and effectively cools the dressed atom state to a low temperature.

  13. Performance experience with the CEBAF SRF cavities

    Energy Technology Data Exchange (ETDEWEB)

    Reece, C.; Benesch, J.; Drury, M.; Hovater, C.; Mammosser, J.; Preble, J.

    1995-12-31

    The full complement of 169 pairs of niobium superconducting cavities has been installed in the CEBAF accelerator. This paper surveys the performance characteristics of these cavities in vertical tests, commissioning in the tunnel, and operational experience to date. Although installed performance exceeds specifications, and 3.2 GeV beam has been delivered on target, present systems do not consistently preserve the high performance obtained in vertical dewar tests as operational capability. Principal sources of these limitations are discussed.

  14. Ultrasensitive and broadband magnetometry with cavity optomechanics

    DEFF Research Database (Denmark)

    Li, Bei-Bei; Bulla, Douglas; Bilek, Jan

    2017-01-01

    We achieved sensitivity of 30 pT/Hz1/2 and working bandwidth larger than 100 MHz, using cavity optomechanical magnetometry, and also demonstrated quantum light enhanced sensitivity in such a magnetometer.......We achieved sensitivity of 30 pT/Hz1/2 and working bandwidth larger than 100 MHz, using cavity optomechanical magnetometry, and also demonstrated quantum light enhanced sensitivity in such a magnetometer....

  15. Quantum cavities with alternating boundary conditions

    Science.gov (United States)

    Facchi, Paolo; Garnero, Giancarlo; Ligabò, Marilena

    2018-03-01

    We consider the quantum dynamics of a free nonrelativistic particle moving in a cavity and we analyze the effect of a rapid switching between two different boundary conditions. We show that this procedure induces, in the limit of infinitely frequent switchings, a new effective dynamics in the cavity related to a novel boundary condition. We obtain a dynamical composition law for boundary conditions which gives the emerging boundary condition in terms of the two initial ones.

  16. Early 500 MHz prototype LEP RF Cavity with superposed storage cavity

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    The principle of transferring the RF power back and forth between the accelerating cavity and a side-coupled storage cavity was demonstrated with this 500 MHz prototype. In LEP, the accelerating frequency was 352.2 MHz, and accelerating and storage cavities were consequently larger. See also 8002294, 8006061, 8407619X, and Annual Reports 1980, p.115; 1981, p.95; 1985, vol.I, p.13.

  17. User's guide for MIRVAL: a computer code for comparing designs of heliostat-receiver optics for central receiver solar power plants

    Energy Technology Data Exchange (ETDEWEB)

    Leary, P L; Hankins, J D

    1979-02-01

    MIRVAL is a Monte Carlo program which simulates the heliostats and a portion of the receiver for solar energy central receiver power plants. Models for three receiver types and four kinds of heliostats are included in the code. The three receiver types modeled are an external cylinder, a cylindrical cavity with a downward-facing aperature, and a north-facing cavity. Three heliostats which track in elevation and azimuth are modeled, one of which is enclosed in a plastic dome. The fourth type consists of a rack of louvered reflective panels with the rack rotatable about a fixed horizontal axis. Phenomena whose effects are simulated are shadowing, blocking, mirror tracking, random errors in tracking and in the conformation of the reflective surface, optical figure of the reflective surface, insolation, angular distribution of incoming sun rays to account for limb darkening and scattering, attenuation of light between the mirrors and the receiver, reflectivity of the mirror surface, and mirror aiming strategy.

  18. Study of CSR longitudinal bunch compression cavity

    International Nuclear Information System (INIS)

    Yin Dayu; Li Peng; Liu Yong; Xie Qingchun

    2009-01-01

    The scheme of longitudinal bunch compression cavity for the Cooling Storage Ring (CSR)is an important issue. Plasma physics experiments require high density heavy ion beam and short pulsed bunch,which can be produced by non-adiabatic compression of bunch implemented by a fast compression with 90 degree rotation in the longitudinal phase space. The phase space rotation in fast compression is initiated by a fast jump of the RF-voltage amplitude. For this purpose, the CSR longitudinal bunch compression cavity, loaded with FINEMET-FT-1M is studied and simulated with MAFIA code. In this paper, the CSR longitudinal bunch compression cavity is simulated and the initial bunch length of 238 U 72+ with 250 MeV/u will be compressed from 200 ns to 50 ns.The construction and RF properties of the CSR longitudinal bunch compression cavity are simulated and calculated also with MAFIA code. The operation frequency of the cavity is 1.15 MHz with peak voltage of 80 kV, and the cavity can be used to compress heavy ions in the CSR. (authors)

  19. The CEBAF Separator Cavity Resonance Control System

    CERN Document Server

    Wissmann, Mark J; Hovater, Curt; Plawski, Tomasz

    2005-01-01

    The CEBAF energy upgrade from 6 GeV to 12GeV will increase the range of beam energies available to the experimental halls. RF deflection cavities (separators) are used to direct the electron beam to the three experimental halls. Consequently with the increase in RF separator cavity gradient needed for the higher energies, RF power will also increase requiring the cavities to have active resonance control. At the 6 GeV energy, the cavities are tuned mechanically and then stabilized with Low Conductivity Water (LCW), which is maintained at constant temperature of 95o Fahrenheit. This is no longer feasible and an active resonance control system, that controls both water temperature and flow has been built. The system uses a commercial PLC with embedded PID controls to control water temperature and flow to the cavities. The system allows the operator to remotely adjust temperature/flow and consequently cavity resonance for the full range of beam energies. Ultimately closed loop control will be maintained by monit...

  20. Estimating tree cavity distributions from historical FIA data

    Science.gov (United States)

    Mark D. Nelson; Charlotte. Roy

    2012-01-01

    Tree cavities provide important habitat features for a variety of wildlife species. We describe an approach for using historical FIA data to estimate the number of trees containing cavities during the 1990s in seven states of the Upper Midwest. We estimated a total of 280 million cavity-containing trees. Iowa and Missouri had the highest percentages of cavity-...

  1. Soliton laser: A computational two-cavity model

    DEFF Research Database (Denmark)

    Berg, P.; If, F.; Christiansen, Peter Leth

    1987-01-01

    An improved computational two-cavity model of the soliton laser proposed and designed by Mollenauer and Stolen [Opt. Lett. 9, 13 (1984)] is obtained through refinements of (i) the laser cavity model, (ii) the pulse propagation in the fiber cavity, and (iii) the coupling between the two cavities...

  2. RF BREAKDOWN STUDIES USING PRESSURIZED CAVITIES

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Rolland

    2014-09-21

    Many present and future particle accelerators are limited by the maximum electric gradient and peak surface fields that can be realized in RF cavities. Despite considerable effort, a comprehensive theory of RF breakdown has not been achieved and mitigation techniques to improve practical maximum accelerating gradients have had only limited success. Part of the problem is that RF breakdown in an evacuated cavity involves a complex mixture of effects, which include the geometry, metallurgy, and surface preparation of the accelerating structures and the make-up and pressure of the residual gas in which plasmas form. Studies showed that high gradients can be achieved quickly in 805 MHz RF cavities pressurized with dense hydrogen gas, as needed for muon cooling channels, without the need for long conditioning times, even in the presence of strong external magnetic fields. This positive result was expected because the dense gas can practically eliminate dark currents and multipacting. In this project we used this high pressure technique to suppress effects of residual vacuum and geometry that are found in evacuated cavities in order to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of magnetic field, frequency, and surface preparation. One of the interesting and useful outcomes of this project was the unanticipated collaborations with LANL and Fermilab that led to new insights as to the operation of evacuated normal-conducting RF cavities in high external magnetic fields. Other accomplishments included: (1) RF breakdown experiments to test the effects of SF6 dopant in H2 and He gases with Sn, Al, and Cu electrodes were carried out in an 805 MHz cavity and compared to calculations and computer simulations. The heavy corrosion caused by the SF6 components led to the suggestion that a small admixture of oxygen, instead of SF6, to the hydrogen would allow the same advantages without the corrosion in a practical muon beam line. (2) A

  3. CERN apprentice receives award

    CERN Multimedia

    2008-01-01

    Another CERN apprentice has received an award for the quality of his work. Stéphane Küng (centre), at the UIG ceremony last November, presided over by Geneva State Councillor Pierre-François Unger, Head of the Department of Economics and Health. Electronics technician Stéphane Küng was honoured in November by the Social Foundation of the Union Industrielle Genevoise (UIG) as one of Geneva’s eight best apprentices in the field of mechatronics. The 20-year-old Genevan obtained his Federal apprentice’s certificate (Certificat fédéral de capacité - CFC) in June 2007, achieving excellent marks in his written tests at the Centre d’Enseignement Professionnel Technique et Artisanal (CEPTA). Like more than 200 youngsters before him, Stéphane Küng spent part of his four-year sandwich course working at CERN, where he followed many practical training courses and gained valuable hands-on experience in various technical groups and labs. "It’ always very gr...

  4. High field conditioning of cryogenic RF cavities

    International Nuclear Information System (INIS)

    Cole, M.; Debiak, T.; Lom, C.; Shephard, W.; Sredniawski, J.

    1993-01-01

    Space-based and other related accelerators have conditioning and operation requirements that are not found in most machines. The use of cryogenic copper, relatively poor vacuum, and limited power storage and operating time put unusual demands on the high-field conditioning process and present some concerns. Two CW cryogenic engineering model open-quotes sparkerclose quotes cavities have been fabricated and tested to fairly high field levels. Tests included initial and repeated conditioning as well as sustained RF operations. The two cavities were an engineering model TDL and an engineering model RFQ. Both cavities operated at 425 MHz. The DTL was conditioned to 46 MV/m at 100% duty factor (CW) at cryogenic temperature. This corresponds to a gap voltage of 433 kV and a real estate accelerating gradient (energy gain/total cavity length) of 6.97 MV/m. The authors believe this to be record performance for cryo CW operation. During cryo pulsed operation, the same cavity reached 48 MV/m with 200 μsec pulses at 0.5% DF. The RFQ was conditioned to 30 MV/m CW at cryo, 85 kV gap voltage. During a brief period of cryo pulsed operation, the RFQ operated at 46 MV/m, or 125 kV gap voltage. Reconditioning experiments were performed on both cavities and no problems were encountered. It should be noted that the vacuum levels were not very stringent during these tests and no special cleanliness or handling procedures were followed. The results of these tests indicate that cavities can run CW without difficulty at cryogenic temperatures at normal conservative field levels. Higher field operation may well be possible, and if better vacuums are used and more attention is paid to cleanliness, much higher fields may be attainable

  5. Natural cavity characteristics and cavity bird abundance on West Virginia forested islands of the Ohio River

    Science.gov (United States)

    James T. Anderson; Karen A. Riesz

    2013-01-01

    Wildlife habitats connected with forested islands and their back channels (areas where commercial traffic is prohibited) on the Ohio River are valuable to diverse species. However, quantitative data on the importance of these areas to cavity-nesting birds are lacking. We compared cavity-nesting bird use and habitat between back and navigational channel sides of islands...

  6. Dispersive optomechanics: a membrane inside a cavity

    Energy Technology Data Exchange (ETDEWEB)

    Jayich, A M; Sankey, J C; Zwickl, B M; Yang, C; Thompson, J D; Girvin, S M; Harris, J G E [Department of Physics, Yale University, New Haven, CT (United States); Clerk, A A [Department of Physics, McGill University, Montreal (Canada); Marquardt, F [Department of Physics, Arnold-Sommerfeld-Center for Theoretical Physics and Center for Nanoscience, Muenchen (Germany)], E-mail: jack.harris@yale.edu

    2008-09-15

    We present the results of theoretical and experimental studies of dispersively coupled (or 'membrane in the middle') optomechanical systems. We calculate the linear optical properties of a high finesse cavity containing a thin dielectric membrane. We focus on the cavity's transmission, reflection and finesse as a function of the membrane's position along the cavity axis and as a function of its optical loss. We compare these calculations with measurements and find excellent agreement in cavities with empty-cavity finesses in the range 10{sup 4}-10{sup 5}. The imaginary part of the membrane's index of refraction is found to be {approx}10{sup -4}. We calculate the laser cooling performance of this system, with a particular focus on the less-intuitive regime in which photons 'tunnel' through the membrane on a timescale comparable to the membrane's period of oscillation. Lastly, we present calculations of quantum non-demolition measurements of the membrane's phonon number in the low signal-to-noise regime where the phonon lifetime is comparable to the QND readout time.

  7. Cavity electromagnetically induced transparency with Rydberg atoms

    Science.gov (United States)

    Bakar Ali, Abu; Ziauddin

    2018-02-01

    Cavity electromagnetically induced transparency (EIT) is revisited via the input probe field intensity. A strongly interacting Rydberg atomic medium ensemble is considered in a cavity, where atoms behave as superatoms (SAs) under the dipole blockade mechanism. Each atom in the strongly interacting Rydberg atomic medium (87 Rb) follows a three-level cascade atomic configuration. A strong control and weak probe field are employed in the cavity with the ensemble of Rydberg atoms. The features of the reflected and transmitted probe light are studied under the influence of the input probe field intensity. A transparency peak (cavity EIT) is revealed at a resonance condition for small values of input probe field intensity. The manipulation of the cavity EIT is reported by tuning the strength of the input probe field intensity. Further, the phase and group delay of the transmitted and reflected probe light are studied. It is found that group delay and phase in the reflected light are negative, while for the transmitted light they are positive. The magnitude control of group delay in the transmitted and reflected light is investigated via the input probe field intensity.

  8. Multi-Mode Cavity Accelerator Structure

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yong [Yale Univ., New Haven, CT (United States); Hirshfield, Jay Leonard [Omega-P R& D, Inc., New Haven, CT (United States)

    2016-11-10

    This project aimed to develop a prototype for a novel accelerator structure comprising coupled cavities that are tuned to support modes with harmonically-related eigenfrequencies, with the goal of reaching an acceleration gradient >200 MeV/m and a breakdown rate <10-7/pulse/meter. Phase I involved computations, design, and preliminary engineering of a prototype multi-harmonic cavity accelerator structure; plus tests of a bimodal cavity. A computational procedure was used to design an optimized profile for a bimodal cavity with high shunt impedance and low surface fields to maximize the reduction in temperature rise ΔT. This cavity supports the TM010 mode and its 2nd harmonic TM011 mode. Its fundamental frequency is at 12 GHz, to benchmark against the empirical criteria proposed within the worldwide High Gradient collaboration for X-band copper structures; namely, a surface electric field Esurmax< 260 MV/m and pulsed surface heating ΔTmax< 56 °K. With optimized geometry, amplitude and relative phase of the two modes, reductions are found in surface pulsed heating, modified Poynting vector, and total RF power—as compared with operation at the same acceleration gradient using only the fundamental mode.

  9. A spherical cavity model for quadrupolar dielectrics

    Science.gov (United States)

    Dimitrova, Iglika M.; Slavchov, Radomir I.; Ivanov, Tzanko; Mosbach, Sebastian

    2016-03-01

    The dielectric properties of a fluid composed of molecules possessing both dipole and quadrupole moments are studied based on a model of the Onsager type (molecule in the centre of a spherical cavity). The dielectric permittivity ɛ and the macroscopic quadrupole polarizability αQ of the fluid are related to the basic molecular characteristics (molecular dipole, polarizability, quadrupole, quadrupolarizability). The effect of αQ is to increase the reaction field, to bring forth reaction field gradient, to decrease the cavity field, and to bring forth cavity field gradient. The effects from the quadrupole terms are significant in the case of small cavity size in a non-polar liquid. The quadrupoles in the medium are shown to have a small but measurable effect on the dielectric permittivity of several liquids (Ar, Kr, Xe, CH4, N2, CO2, CS2, C6H6, H2O, CH3OH). The theory is used to calculate the macroscopic quadrupolarizabilities of these fluids as functions of pressure and temperature. The cavity radii are also determined for these liquids, and it is shown that they are functions of density only. This extension of Onsager's theory will be important for non-polar solutions (fuel, crude oil, liquid CO2), especially at increased pressures.

  10. CERN Developments for 704 MHz Superconducting Cavities

    CERN Document Server

    Capatina, O; Aviles Santillana, I; Arnau Izquierdo, G; Bonomi, R; Calatroni, S; Chambrillon, J; Gerigk, F; Garoby, R; Guinchard, M; Junginger, T; Malabaila, M; Marques Antunes Ferreira, L; Mikulas, S; Parma, V; Pillon, F; Renaglia, T; Schirm, K; Tardy, T; Therasse, M; Vacca, A; Valverde Alonso, N; Vande Craen, A

    2013-01-01

    The Superconducting Proton Linac (SPL) is an R&D effort coordinated by CERN in partnership with other international laboratories. It is aiming at developing key technologies for the construction of a multi-megawatt proton linac based on state-of-the-art RF superconducting technology, which would serve as a driver in new physics facilities for neutrinos and/or Radioactive Ion Beam (RIB). Amongst the main objectives of this R&D effort, is the development of 704 MHz bulk niobium beta=1 elliptical cavities, operating at 2 K with a maximum accelerating gradient of 25 MV/m, and the testing of a string of cavities integrated in a machine-type cryomodule. The cavity together with its helium tank had to be carefully designed in coherence with the innovative design of the cryomodule. New fabrication methods have also been explored. Five such niobium cavities and two copper cavities are in fabrication. The key design aspects are discussed, the results of the alternative fabrication methods presented and the stat...

  11. Long Wave Infrared Cavity Enhanced Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Taubman, Matthew S.; Scott, David C.; Cannon, Bret D.; Myers, Tanya L.; Bonebrake, Christopher A.; Aker, Pam M.; Wojcik, Michael D.; Munley, John T.; Nguyen, Vinh T.; Schultz, John F.

    2004-10-01

    The principal goal of Pacific Northwest National Laboratory's (PNNL's) long wave infrared (LWIR) cavity enhanced sensor (CES) project is to explore ultra-sensitive spectroscopic techniques and apply them to the development of LWIR chemical sensors needed for detecting weapons proliferation. This includes detecting not only the weapons of mass destruction (WMDs) themselves, but also signatures of their production and/or detonation. The LWIR CES project is concerned exclusively with developing point sensors; other portions of PNNL's IR Sensors program address stand off detection. PNNL's LWIR CES research is distinguished from that done by others by the use quantum cascade lasers (QCLs) as the light source. QCLs are novel devices, and a significant fraction of our research has been devoted to developing the procedures and hardware required to implement them most effectively for chemical sensing. This report details the progress we have made on our LWIR CES sensor development. During FY02, PNNL investigated three LWIR CES implementations beginning with the easiest to implement, direct cavity-enhanced detection (simple CES), including a technique of intermediate difficulty, cavity-dithered phase-sensitive detection (FM recovery CES) through to the most complex technique, that of resonant sideband cavity-enhanced detection also known as noise-immune cavity-enhanced optical heterodyne molecular spectroscopy, or NICE-OHMS.

  12. Influence of void ratio on thermal performance of heat pipe receiver

    International Nuclear Information System (INIS)

    Gui Xiaohong; Tang Dawei; Liang Shiqiang; Lin Bin; Yuan Xiugan

    2012-01-01

    Highlights: ► The temperature gradient increases significantly and the utility ratio of PCM decreases obviously as void ratio increases. ► Void cavity influences the process of phase change greatly. ► PCM melts slowly during sunlight periods and freezes slowly during eclipse periods as void ratio increases. ► The temperature gradient of PCM zone is very significant with the effect of void cavity. - Abstract: In this paper, influence of void ratio on thermal performance of heat pipe receiver under microgravity is numerically simulated. Accordingly, mathematical model is set up. Numerical method is offered. The temperature field of Phase Change Material (PCM) canister is shown. Numerical results are compared with numerical ones of National Aeronautics and Space Administration (NASA). Numerical results show that the temperature gradient increases significantly and the utility ratio of PCM decreases obviously as void ratio increases. Void cavity influences the process of phase change greatly. PCM melts slowly during sunlight periods and freezes slowly during eclipse periods as void ratio increases. The thermal resistance of void cavity is much bigger than that of PCM canister wall. Void cavity prevents the heat transfer between PCM zone and canister wall. The temperature gradient of PCM zone is very significant with the effect of void cavity. So the thermal stress of heat pipe receiver may increase, and the lifetime may decrease as void ratio increases.

  13. Scheme for the implementation of a universal quantum cloning machine via cavity-assisted atomic collisions in cavity QED

    International Nuclear Information System (INIS)

    Zou Xubo; Pahlke, K.; Mathis, W.

    2003-01-01

    We propose a scheme to implement the 1→2 universal quantum cloning machine of Buzek and Hillery [Phys. Rev. A 54, 1844 (1996)] in the context of cavity QED. The scheme requires cavity-assisted collision processes between atoms, which cross through nonresonant cavity fields in the vacuum states. The cavity fields are only virtually excited to face the decoherence problem. That's why the requirements on the cavity quality factor can be loosened

  14. TM01 mode accelerating cavity optimization

    International Nuclear Information System (INIS)

    Manca, J.J.; Knapp, E.A.

    1978-08-01

    The cost of an accelerator depends greatly upon the effective use of rf power for particle acceleration. Before completing an accelerator design, an optimization of the accelerating cells relative to the effective shunt impedance should be made to measure the structure's efficiency in providing a high and effective acceleration of particles for a given rf power. Optimization of the accelerating cell resonant at f/sub r/ = 1350 MHz (TM 01 mode) relative to the maximum effective shunt impedance ZT 2 was performed at the Los Alamos Scientific Laboratory using the computer program SUPERFISH. The study was parametric; one parameter was changed while the others were held constant. Frequency adjustments were made by changing the cavity radius. Results presented in this report can be used to design similar cavities at different resonant frequencies or to design a more complicated cavity (TM 02 mode) for the disk and washer structure

  15. Single Atoms in Nearly Concentric Cavity

    Science.gov (United States)

    Utama, Adrian Nugraha; Nguyen, Chi Huan; Lewty, Nick; Kurtsiefer, Christian; Quantum Optics Group Team

    2017-04-01

    Strong interaction between photons and neutral single atoms are usually observed in cavity quantum electrodynamics (CQED) systems with high finesse mirrors and small physical volume. We demonstrate another approach that employs a near concentric cavity with relatively low finesse mirrors ( 100) and large physical separation between mirrors ( 10 mm). The transmission spectrum of our CQED system with trapped single atoms is observed to exhibit two resolved normal mode peaks, in which the single atom cooperativity is estimated to be around 0.4. The cooperativity of the system can be improved further by increasing the finesse of the mirrors or moving the cavity closer to the concentric point. The successful realization of concentric CQED systems will open opportunities for scaling up with applications in quantum computing. This work is supported by the National Research Foundation and Ministry of Education, Singapore.

  16. PEP-II RF cavity revisited

    International Nuclear Information System (INIS)

    Rimmer, R.A.; Koehler, G.; Li, D.; Hartman, N.; Folwell, N.; Hodgson, J.; Ko, K.; McCandless, B.

    1999-01-01

    This report describes the results of numerical simulations of the PEP-II RF cavity performed after the completion of the construction phase of the project and comparisons are made to previous calculations and measured results. These analyses were performed to evaluate new calculation techniques for the HOM distribution and RF surface heating that were not available at the time of the original design. These include the use of a high frequency electromagnetic element in ANSYS and the new Omega 3P code to study wall losses, and the development of broadband time domain simulation methods in MAFIA for the HOM loading. The computed HOM spectrum is compared with cavity measurements and observed beam-induced signals. The cavity fabrication method is reviewed, with the benefit of hindsight, and simplifications are discussed

  17. Enhanced Method for Cavity Impedance Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Frank Marhauser, Robert Rimmer, Kai Tian, Haipeng Wang

    2009-05-01

    With the proposal of medium to high average current accelerator facilities the demand for cavities with extremely low Higher Order Mode (HOM) impedances is increasing. Modern numerical tools are still under development to more thoroughly predict impedances that need to take into account complex absorbing boundaries and lossy materials. With the usually large problem size it is preferable to utilize massive parallel computing when applicable and available. Apart from such computational issues, we have developed methods using available computer resources to enhance the information that can be extracted from a cavities? wakefield computed in time domain. In particular this is helpful for a careful assessment of the extracted RF power and the mitigation of potential beam break-up or emittance diluting effects, a figure of merit for the cavity performance. The method is described as well as an example of its implementation.

  18. Coupled Photonic Crystal Cavity Array Laser

    DEFF Research Database (Denmark)

    Schubert, Martin

    This thesis describes the design, fabrication and characterization of photonic crystal slab lasers. The main focus is on coupled photonic crystal cavity lasers which are examined in great detail. The cavity type which is mainly explored consists of a defect formed by a single missing hole...... in the quadratic lattice. Processing techniques are developed and optimized in order fabricate photonic crystals membranes in gallium arsenide with quantum dots as gain medium and in indium gallium arsenide phosphide with quantum wells as gain medium. Several key issues in process to ensure good quality...... are identified such as the size and material for the carrier wafer in the III-V etch and the importance of removing all remains of the e-beam lithography mask after the etch of the hard mask. Detailed simulations are shown for a simple system with two coupled cavities in different coupling directions...

  19. Circuit QED with 3D cavities

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Edwar; Eder, Peter; Fischer, Michael; Goetz, Jan; Deppe, Frank; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany); Physik-Department, TU Muenchen, 85748 Garching (Germany); Nanosystems Initiative Munich (NIM), 80799 Muenchen (Germany); Haeberlein, Max; Wulschner, Karl Friedrich [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany); Physik-Department, TU Muenchen, 85748 Garching (Germany); Fedorov, Kirill; Marx, Achim [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, 85748 Garching (Germany)

    2016-07-01

    In typical circuit QED systems, on-chip superconducting qubits are coupled to integrated coplanar microwave resonators. Due to the planar geometry, the resonators are often a limiting factor regarding the total coherence of the system. Alternatively, similar hybrid systems can be realized using 3D microwave cavities. Here, we present studies on transmon qubits capacitively coupled to 3D cavities. The internal quality factors of our 3D cavities, machined out of high purity aluminum, are above 1.4 .10{sup 6} at the single photon level and a temperature of 50 mK. For characterization of the sample, we perform dispersive shift measurements up to the third energy level of the qubit. We show simulations and data describing the effect of the transmon geometry on it's capacitive properties. In addition, we present progress towards an integrated quantum memory application.

  20. Minimum wakefield achievable by waveguide damped cavity

    International Nuclear Information System (INIS)

    Lin, X.E.; Kroll, N.M.

    1995-01-01

    The authors use an equivalent circuit to model a waveguide damped cavity. Both exponentially damped and persistent (decay t -3/2 ) components of the wakefield are derived from this model. The result shows that for a cavity with resonant frequency a fixed interval above waveguide cutoff, the persistent wakefield amplitude is inversely proportional to the external Q value of the damped mode. The competition of the two terms results in an optimal Q value, which gives a minimum wakefield as a function of the distance behind the source particle. The minimum wakefield increases when the resonant frequency approaches the waveguide cutoff. The results agree very well with computer simulation on a real cavity-waveguide system

  1. Cavity lining after excavating caries lesions

    DEFF Research Database (Denmark)

    Schwendicke, Falk; Göstemeyer, Gerd; Gluud, Christian

    2015-01-01

    OBJECTIVES: After removal of dentin caries lesions, cavity lining has been advocated. Non-clinical data support this approach, but clinical data are sparse and ambiguous. We aimed at evaluating the benefits and harms of cavity lining using meta-analysis and Trial Sequential Analysis. DATA: We...... included randomized clinical trials comparing restorations without versus with cavity lining for treating primary caries lesions. Only trials reporting failure (defined as need to re-retreat) after ≥1 year follow-up were included. Trial selection, data extraction, and risk of bias assessment were conducted....... STUDY SELECTION: From 128 studies, three randomized trials (89/130 patients or teeth), all treating primary teeth, were included. The trials had high risk of bias. All trials compared no lining versus calcium hydroxide lining after selective caries removal followed by adhesive restoration. Follow...

  2. Prominence Mass Supply and the Cavity

    Science.gov (United States)

    Schmit, Donald J.; Gibson, S.; Luna, M.; Karpen, J.; Innes, D.

    2013-01-01

    A prevalent but untested paradigm is often used to describe the prominence-cavity system; the cavity is under-dense because it it evacuated by supplying mass to the condensed prominence. The thermal non-equilibrium (TNE) model of prominence formation offers a theoretical framework to predict the thermodynamic evolutin of the prominence and the surrounding corona. We examine the evidence for a prominence-cavity connection by comparing the TNE model and diagnostics of dynamic extreme ultraviolet (EUV) emission surrounding the prominence, specifically prominence horns. Horns are correlated extensions of prminence plasma and coronal plasma which appear to connect the prominence and cavity. The TNE model predicts that large-scale brightenings will occur in the Solar Dynamics Observatory Atmospheric Imaging Assembly 171 A badpass near he prominence that are associated with the cooling phase of condensation formation. In our simulations, variations in the magnitude of footpoint heating lead to variations in the duration, spatial scale, and temporal offset between emission enhancements in the other EUV bandpasses. While these predictions match well a subset of the horn observations, the range of variations in the observed structures is not captured by the model. We discuss the implications of one-dimensional loop simulations for the three-dimensional time-averaged equilibrium in the prominence and the cavity. Evidence suggests that horns are likely caused by condensing prominence plasma, but the larger question of whether this process produces a density-depleted cavity requires a more tightly constrained model of heating and better knowledge of the associated magnetic structure.

  3. Long bunch trains measured using a prototype cavity beam position monitor for the Compact Linear Collider

    Directory of Open Access Journals (Sweden)

    F. J. Cullinan

    2015-11-01

    Full Text Available The Compact Linear Collider (CLIC requires beam position monitors (BPMs with 50 nm spatial resolution for alignment of the beam line elements in the main linac and beam delivery system. Furthermore, the BPMs must be able to make multiple independent measurements within a single 156 ns long bunch train. A prototype cavity BPM for CLIC has been manufactured and tested on the probe beam line at the 3rd CLIC Test Facility (CTF3 at CERN. The transverse beam position is determined from the electromagnetic resonant modes excited by the beam in the two cavities of the pickup, the position cavity and the reference cavity. The mode that is measured in each cavity resonates at 15 GHz and has a loaded quality factor that is below 200. Analytical expressions for the amplitude, phase and total energy of signals from long trains of bunches have been derived and the main conclusions are discussed. The results of the beam tests are presented. The variable gain of the receiver electronics has been characterized using beam excited signals and the form of the signals for different beam pulse lengths with the 2/3  ns bunch spacing has been observed. The sensitivity of the reference cavity signal to charge and the horizontal position signal to beam offset have been measured and are compared with theoretical predictions based on laboratory measurements of the BPM pickup and the form of the resonant cavity modes as determined by numerical simulation. Finally, the BPM was calibrated so that the beam position jitter at the BPM location could be measured. It is expected that the beam jitter scales linearly with the beam size and so the results are compared to predicted values for the latter.

  4. Seismic wave interaction with underground cavities

    Science.gov (United States)

    Schneider, Felix M.; Esterhazy, Sofi; Perugia, Ilaria; Bokelmann, Götz

    2016-04-01

    Realization of the future Comprehensive Nuclear Test Ban Treaty (CTBT) will require ensuring its compliance, making the CTBT a prime example of forensic seismology. Following indications of a nuclear explosion obtained on the basis of the (IMS) monitoring network further evidence needs to be sought at the location of the suspicious event. For such an On-Site Inspection (OSI) at a possible nuclear test site the treaty lists several techniques that can be carried out by the inspection team, including aftershock monitoring and the conduction of active seismic surveys. While those techniques are already well established, a third group of methods labeled as "resonance seismometry" is less well defined and needs further elaboration. A prime structural target that is expected to be present as a remnant of an underground nuclear explosion is a cavity at the location and depth the bomb was fired. Originally "resonance seismometry" referred to resonant seismic emission of the cavity within the medium that could be stimulated by an incident seismic wave of the right frequency and observed as peaks in the spectrum of seismic stations in the vicinity of the cavity. However, it is not yet clear which are the conditions for which resonant emissions of the cavity could be observed. In order to define distance-, frequency- and amplitude ranges at which resonant emissions could be observed we study the interaction of seismic waves with underground cavities. As a generic model for possible resonances we use a spherical acoustic cavity in an elastic full-space. To solve the forward problem for the full elastic wave field around acoustic spherical inclusions, we implemented an analytical solution (Korneev, 1993). This yields the possibility of generating scattering cross-sections, amplitude spectrums and synthetic seismograms for plane incident waves. Here, we focus on the questions whether or not we can expect resonant responses in the wave field scattered from the cavity. We show

  5. Plasma processing of superconducting radio frequency cavities

    Science.gov (United States)

    Upadhyay, Janardan

    The development of plasma processing technology of superconducting radio frequency (SRF) cavities not only provides a chemical free and less expensive processing method, but also opens up the possibility for controlled modification of the inner surfaces of the cavity for better superconducting properties. The research was focused on the transition of plasma etching from two dimensional flat surfaces to inner surfaces of three dimensional (3D) structures. The results could be applicable to a variety of inner surfaces of 3D structures other than SRF cavities. Understanding the Ar/Cl2 plasma etching mechanism is crucial for achieving the desired modification of Nb SRF cavities. In the process of developing plasma etching technology, an apparatus was built and a method was developed to plasma etch a single cell Pill Box cavity. The plasma characterization was done with the help of optical emission spectroscopy. The Nb etch rate at various points of this cavity was measured before processing the SRF cavity. Cylindrical ring-type samples of Nb placed on the inner surface of the outer wall were used to measure the dependence of the process parameters on plasma etching. The measured etch rate dependence on the pressure, rf power, dc bias, temperature, Cl2 concentration and diameter of the inner electrode was determined. The etch rate mechanism was studied by varying the temperature of the outer wall, the dc bias on the inner electrode and gas conditions. In a coaxial plasma reactor, uniform plasma etching along the cylindrical structure is a challenging task due to depletion of the active radicals along the gas flow direction. The dependence of etch rate uniformity along the cylindrical axis was determined as a function of process parameters. The formation of dc self-biases due to surface area asymmetry in this type of plasma and its variation on the pressure, rf power and gas composition was measured. Enhancing the surface area of the inner electrode to reduce the

  6. Coherent acoustic excitation of cavity polaritons

    DEFF Research Database (Denmark)

    Poel, Mike van der; de Lima, M. M.; Hey, R.

    and highly nonlinear optical response.Our sample consists of epitaxially grown GaAs/AlGaAs QWs located at the anti-node ofa high Q lambda cavity, which is resonant with the QW excitonic transition3. The SAWfield, which is excited by an interdigital transducer on the piezoelectric GaAs samplesurface......, modulates the refractive index and displaces the material causing a harmonicmodulation of the PBG structure1. This periodic modulation of the cavity-exciton systemleads to in-plane mini-Brillouin zone (MBZ) formation. The very high vacuum-Rabisplitting of our sample enables us to clearly resolve...

  7. Electrically Pumped Vertical-Cavity Amplifiers

    DEFF Research Database (Denmark)

    Greibe, Tine

    2007-01-01

    . Detailed descriptions of the structure designs, clean room processing procedures and characterisations of the designs are presented in this thesis. Furthermore, comprehensive simulations of carrier distributions in the quantum well sections and the gain saturation of the different designs are performed...... of one of our bottom-emitting designs are good. It has an optical output power that is promising for use in an external-cavity mode-locked laser. The growth of the structure however went wrong and the structure has no net gain, which spoiled our chances to investigate it further in an external cavity...

  8. Parasitic Cavities Losses in SPEAR-2

    Energy Technology Data Exchange (ETDEWEB)

    Sands, M.; /SLAC

    2016-12-19

    In PEP the large number of particles in a bunch, together with the small bunch length, may cause grievous energy loss from the beam to parasitic modes in the accelerating cavities. I have recently tried to estimate the parasitic cavity in PEP, based on a paper of Keil and I have obtained the result that the loss to parasitic modes will be about 10 MeV per particle per revolution for a bunch length of about 10 cm. In this note, I bring together some of the considerations that might bear on an experimental investigation of the loss using SPEAR-2.

  9. Short-cavity squeezing in barium

    Science.gov (United States)

    Hope, D. M.; Bachor, H-A.; Manson, P. J.; Mcclelland, D. E.

    1992-01-01

    Broadband phase sensitive noise and squeezing were experimentally observed in a system of barium atoms interacting with a single mode of a short optical cavity. Squeezing of 13 +/- 3 percent was observed. A maximum possible squeezing of 45 +/- 8 percent could be inferred for out experimental conditions, after correction for measured loss factors. Noise reductions below the quantum limit were found over a range of detection frequencies 60-170 MHz and were best for high cavity transmission and large optical depths. The amount of squeezing observed is consistent with theoretical predictions from a full quantum statistical model of the system.

  10. Numerical simulation of coupler cavities for linacs

    Energy Technology Data Exchange (ETDEWEB)

    Ng, C.K.; Derutyer, H.; Ko, K.

    1993-04-01

    We present numerical procedures involved in the evaluation of the performance of coupler cavities for linacs. The MAFIA code is used to simulate an X-Band accelerator section in the time domain. The input/output coupler cavities for the structure arc of the symmetrical double-input design. We calculate the transmission properties of the coupler and compare the results with measurements. We compare the performance of the symmetrical double-input design with that of the conventional single-input type by evaluating the field amplitude and phase asymmetries. We also evaluate the peak field gradient in the computer.

  11. Coupled Geomechanical Simulations of UCG Cavity Evolution

    Energy Technology Data Exchange (ETDEWEB)

    Morris, J P; Buscheck, T A; Hao, Y

    2009-07-13

    This paper presents recent work from an ongoing project to develop predictive tools for cavity/combustion-zone growth and to gain quantitative understanding of the processes and conditions (both natural and engineered) affecting underground coal gasification (UCG). In this paper we will focus upon the development of coupled geomechanical capabilities for simulating the evolution of the UCG cavity using discrete element methodologies. The Discrete Element Method (DEM) has unique advantages for facilitating the prediction of the mechanical response of fractured rock masses, such as cleated coal seams. In contrast with continuum approaches, the interfaces within the coal can be explicitly included and combinations of both elastic and plastic anisotropic response are simulated directly. Additionally, the DEM facilitates estimation of changes in hydraulic properties by providing estimates of changes in cleat aperture. Simulation of cavity evolution involves a range of coupled processes and the mechanical response of the host coal and adjoining rockmass plays a role in every stage of UCG operations. For example, cavity collapse during the burn has significant effect upon the rate of the burn itself. In the vicinity of the cavity, collapse and fracturing may result in enhanced hydraulic conductivity of the rock matrix in the coal and caprock above the burn chamber. Even far from the cavity, stresses due to subsidence may be sufficient to induce new fractures linking previously isolated aquifers. These mechanical processes are key in understanding the risk of unacceptable subsidence and the potential for groundwater contamination. These mechanical processes are inherently non-linear, involving significant inelastic response, especially in the region closest to the cavity. In addition, the response of the rock mass involves both continuum and discrete mechanical behavior. We have recently coupled the LDEC (Livermore Distinct Element Code) and NUFT (Non

  12. Accelerating RF cavity of the Booster

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    Each of the 4 PS Booster rings has a single accelerating cavity. It consists of 2 quarter-wave ferrite-loaded resonators. There are 2 figure-of-eight loops on the ferrite loads for tuning the frequency throughout the acceleration cycle, from 3 to 8 MHz (from 50 MeV at injection to the original Booster energy of 800 MeV, 2 GeV today). The cavities have a flat design, to fit the ring-to-ring distance of 36 cm. The tube for forced-air cooling is visible in the left front. See also 8301084.

  13. Accelerating RF cavity of the Booster

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Each of the 4 PS Booster rings has a single accelerating cavity.It consists of 2 quarter-wave ferrite-loaded resonators. 2 figure-of-eight loops tune the frequency throughout the accelerating cycle, from 3 to 8 MHz (from 50 MeV at injection to the original Booster energy of 800 MeV, 2 GeV today). The cavities have a flat design, to fit the ring-to-ring distance of 36 cm, and are forced-air cooled. The 2 round objects in the front-compartments are the final-stage power-tetrodes. See also 8111095.

  14. Short-cavity squeezing in barium

    International Nuclear Information System (INIS)

    Hope, D.M.; Bachor, H-A.; Manson, P.J.; Mcclelland, D.E.

    1992-01-01

    Broadband phase sensitive noise and squeezing were experimentally observed in a system of barium atoms interacting with a single mode of a short optical cavity. Squeezing of 13 +/- 3 percent was observed. A maximum possible squeezing of 45 +/- 8 percent could be inferred for out experimental conditions, after correction for measured loss factors. Noise reductions below the quantum limit were found over a range of detection frequencies 60-170 MHz and were best for high cavity transmission and large optical depths. The amount of squeezing observed is consistent with theoretical predictions from a full quantum statistical model of the system

  15. Progress in diagnostic techniques for sc cavities

    International Nuclear Information System (INIS)

    Reece, C.E.

    1988-01-01

    While routinely achieved performance characteristics of superconducting cavities have now reached a level which makes them useful in large scale applications, achieving this level has come only through the knowledge gained by systematic studies of performance limiting phenomena. Despite the very real progress that has been made, the routine performance of superconducting cavities still falls far short of both the theoretical expectations and the performance of a few exception examples. It is the task of systematically applied diagnostic techniques to reveal additional information concerning the response of superconducting surfaces to applied RF fields. Here recent developments in diagnostic techniques are discussed. 18 references, 12 figures

  16. Outcomes of oral cavity squamous cell carcinoma in pediatric patients.

    Science.gov (United States)

    Morris, Luc G T; Ganly, Ian

    2010-04-01

    Oral cavity squamous cell carcinoma (OCSCC) is uncommon in young patients and rare in the pediatric population. OCSCC is believed to behave aggressively in this age group, but the existing literature is limited to case reports. The objective of this study was to compare survival outcomes in pediatric and adult patients with oral cavity squamous cell carcinoma. We performed a population-based study of 54 pediatric (age cancer registry. Overall survival (OS) and disease-specific survival (DSS) were analyzed using the Kaplan-Meier method. Cox multivariable regression was used to control for covariates including gender, stage, histologic grade and treatment modality. Pediatric patients with OCSCC experienced significantly better 5 year DSS than adult patients (75.3% vs. 63.5%, p=0.02). Pediatric patients were also more likely to be female (37.0% vs. 31.7%, p=0.04) and to receive surgery (87.0% vs. 68.6%, ppediatric and adult groups experienced equivalent DSS (p=0.64). Pediatric patients with OCSCC experience better survival than adult patients. When differences in patient, tumor and treatment-related characteristics are adjusted for, the two groups experience equivalent survival. Copyright 2010 Elsevier Ltd. All rights reserved.

  17. Advanced acoustic cavity technology. [for hydrogen oxygen rocket engines

    Science.gov (United States)

    Hines, W. S.; Oberg, C. L.; Kusak, L.

    1974-01-01

    A series of rocket motor firings was performed in a modified linear aerospike thrust chamber with the H2/O2 propellant combination to allow determination of the physical properties of the combustion gases in acoustic cavities located in the chamber side walls. A preliminary analytical study was first conducted to define theoretically both the appropriate cavity dimensions and the combustion gas flow field adjacent to the cavity openings. During the subsequent motor firings, cavity gas temperature profiles were measured and gas samples were withdrawn from the bottom of the cavities for compositional analysis by measurement of pressure/temperature variation and gas chromatography. Data were obtained with both radially and axially oriented cavities and with and without hydrogen bleed flow through the cavities. A simplified procedure was developed for predicting gas cavity and acoustic velocity for use in acoustic cavity design analyses.

  18. School-Based Dental Sealant Programs Prevent Cavities And Are Cost-Effective.

    Science.gov (United States)

    Griffin, Susan; Naavaal, Shillpa; Scherrer, Christina; Griffin, Paul M; Harris, Kate; Chattopadhyay, Sajal

    2016-12-01

    Untreated cavities can have far-reaching negative consequences for people's ability to eat, speak, and learn. By adolescence, 27 percent of low-income children in the United States will have untreated cavities. School-based sealant programs typically provide dental sealants (a protective coating that adheres to the surface of molars) at little or no cost to students attending schools in areas with low socioeconomic status. These programs have been shown to increase the number of students receiving sealants and to prevent cavities. We analyzed the cost-effectiveness of school sealant programs using data (from school programs in fourteen states between 2013 and 2014) on children's cavity risk, including the effects of untreated cavities on a child's quality of life. We found that providing sealants in school programs to 1,000 children would prevent 485 fillings and 1.59 disability-adjusted life-years. School-based sealant programs saved society money and remained cost-effective across a wide range of reasonable values. Project HOPE—The People-to-People Health Foundation, Inc.

  19. GNSS Software Receiver for UAVs

    DEFF Research Database (Denmark)

    Olesen, Daniel Madelung; Jakobsen, Jakob; von Benzon, Hans-Henrik

    2016-01-01

    This paper describes the current activities of GPS/GNSS Software receiver development at DTU Space. GNSS Software receivers have received a great deal of attention in the last two decades and numerous implementations have already been presented. DTU Space has just recently started development of ...... of our own GNSS software-receiver targeted for mini UAV applications, and we will in in this paper present our current progress and briefly discuss the benefits of Software Receivers in relation to our research interests.......This paper describes the current activities of GPS/GNSS Software receiver development at DTU Space. GNSS Software receivers have received a great deal of attention in the last two decades and numerous implementations have already been presented. DTU Space has just recently started development...

  20. Influence from cavity decay on geometric quantum computation in the large-detuning cavity QED model

    International Nuclear Information System (INIS)

    Chen Changyong; Zhang Xiaolong; Deng Zhijiao; Gao Kelin; Feng Mang

    2006-01-01

    We introduce a general displacement operator to investigate the unconventional geometric quantum computation with dissipation under the model of many identical three-level atoms in a cavity, driven by a classical field. Our concrete calculation is made for the case of two atoms, based on a previous scheme [S.-B. Zheng, Phys. Rev. A 70, 052320 (2004)] for the large-detuning interaction of the atoms with the cavity mode. The analytical results we present will be helpful for experimental realization of geometric quantum computation in real cavities

  1. A concentrated solar cavity absorber with direct heat transfer through recirculating metallic particles

    Energy Technology Data Exchange (ETDEWEB)

    Sarker, M. R. I., E-mail: islamrabiul@yahoo.com; Saha, Manabendra, E-mail: manabendra.saha@adelaide.edu.au, E-mail: manab04me@gmail.com; Beg, R. A. [Department of Mechanical Engineering, Rajshahi University of Engineering and Technology, Rajshahi-6204 (Bangladesh)

    2016-07-12

    A recirculating flow solar particle cavity absorber (receiver) is modeled to investigate the flow behavior and heat transfer characteristics of a novel developing concept. It features a continuous recirculating flow of non-reacting metallic particles (black silicon carbide) with air which are used as a thermal enhancement medium. The aim of the present study is to numerically investigate the thermal behavior and flow characteristics of the proposed concept. The proposed solar particle receiver is modeled using two phase discrete particle model (DPM), RNG k-flow model and discrete ordinate (DO) radiation model. Numerical analysis is carried out considering a solar receiver with only air and the mixture of non-reacting particles and air as a heat transfer as well as heat carrying medium. The parametric investigation is conducted considering the incident solar flux on the receiver aperture and changing air flow rate and recirculation rate inside the receiver. A stand-alone feature of the recirculating flow solar particle receiver concept is that the particles are directly exposed to concentrated solar radiation monotonously through recirculating flow inside the receiver and results in efficient irradiation absorption and convective heat transfer to air that help to achieve high temperature air and consequently increase in thermal efficiency. This paper presents, results from the developed concept and highlights its flow behavior and potential to enhance the heat transfer from metallic particles to air by maximizing heat carrying capacity of the heat transfer medium. The imposed milestones for the present system will be helpful to understand the radiation absorption mechanism of the particles in a recirculating flow based receiver, the thermal transport between the particles, the air and the cavity, and the fluid dynamics of the air and particle in the cavity.

  2. Injector Cavities Fabrication, Vertical Test Performance and Primary Cryomodule Design

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haipeng [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Cheng, Guangfeng [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Clemens, William [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Davis, G [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Macha, Kurt [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Overton, Roland [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Spell, D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    After the electromagnetic design and the mechanical design of a β=0.6, 2-cell elliptical SRF cavity, the cavity has been fabricated. Then both 2-cell and 7-cell cavities have been bench tuned to the target values of frequency, coupling external Q and field flatness. After buffer chemistry polishing (BCP) and high pressure rinses (HPR), Vertical 2K cavity test results have been satisfied the specifications and ready for the string assembly. We will report the cavity performance including Lorenz Force Detuning (LFD) and Higher Order Modes (HOM) damping data. Its integration with cavity tuners to the cryomodule design will be reported.

  3. Screening for Oral Cavity Cancer: A 1-year Experience of a Regional Hospital in Taiwan.

    Science.gov (United States)

    Chi, T H; Yuan, C H; Chen, R F

    2014-01-01

    The purpose of this study was to analyze the risk factors affecting precancerous lesions, and cancer of oral cavity, and to assess efficacy of visual screening for oral mucosal lesions. The medical records of patients older than 30 years of age with history of habitual cigarette smoking or betel quid chewing that received screening for oral mucosal lesions between January 2012 and December 2012 were retrospectively reviewed. The patients' age, gender, risk factors, screening findings, and histopathology results of biopsy were included for further analysis. A total of 1341 patients were enrolled in this study. There were 1080 males and 261 females ranging from 30 to 96 years of age, with a mean age of 53.9±13.6 years. After screening, 226 (16.9%) were found to be positive of oral lesions. Among these 226 patients, 69 (30.5%) underwent biopsy under local anesthesia, and the histopathology showed malignancy in 13 (5.8%). All of the confirmed malignant cases were squamous cell carcinoma. Among them, 12 received further staging examination and one was lost to follow-up resulting in unknown stage. The early stage oral cavity cancer (stage I and II) accounted for 84.6% (11/13). The detection rate of early stage oral cavity cancer in our study was reasonable. Therefore, visual screening for oral cavity cancer is recommended for patients with habitual cigarette smoking or betel quid chewing.

  4. Atmospheric signals produced by cavity rebound

    International Nuclear Information System (INIS)

    Jones, E.M.; App, F.N.; Whitaker, R.W.

    1993-01-01

    An analysis of the atmospheric acoustic signals produced by a class of low-yield tests conducted just below the base of the alluvial cover in Yucca Flat of the Nevada Test Site (NTS), has revealed a clear manifestation of an elastic, cavity rebound signal. We use modeling as the basis for understanding the observed phenomena

  5. AGN Heating Through Cavities and Shocks

    NARCIS (Netherlands)

    Nulsen, P.E.J.; Jones, C.; Forman, W.R.; David, L.P.; McNamara, B.R.; Rafferty, D.A.; Bîrzan, L.; Wise, M.

    2007-01-01

    Three comments are made on AGN heating of cooling flows. A simple physical argument is used to show that the enthalpy of a buoyant radio lobe is converted to heat in its wake. Thus, a significant part of ``cavity'' enthalpy is likely to end up as heat. Second, the properties of the repeated weak

  6. Lambda shifted photonic crystal cavity laser

    DEFF Research Database (Denmark)

    Schubert, Martin; Skovgård, Troels Suhr; Ek, Sara

    2010-01-01

    We propose and demonstrate an alternative type of photonic crystal laser design that shifts all the holes in the lattice by a fixed fraction of the targeted emission wavelength. The structures are realized in InGaAsP =1.15 with InGaAsP quantum wells =1.52 as gain material. Cavities with shifts of...

  7. The Design of the Orthogonal Box Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Moretti, Alfred; /Fermilab

    2010-09-15

    The muon collider and/or the neutrino factory require large accelerating electric field gradients immersed in large (3 to 6 T) solenoidal magnetic fields for ionization cooling of muon beams. Our original vacuum breakdown study demonstrated a loss of achievable peak accelerating gradient in solenoidal magnetic fields by a factor 2 or greater. The Muon Collaboration has developed a theory of a method to suppress high electric field breakdown in vacuum cavities needed for a Muon collider or neutrino factory. It has been shown in our studies and by others that high gradient electric field emitted electrons (dark current) are the primary cause of breakdown. A DC magnetic field orthogonal to the RF electric accelerating field prevents dark current high field emitted electrons from traveling across the accelerating gap and then will prevent breakdown. We have decided to test this theory by building a special cavity in the shape of vacuum box. Figure 1 is a simplified view of the cavity design. The design is based on an 805 MHz WR975 waveguide cavity resonating in the TE{sub 101} mode. For the TE{sub 101} mode the resonant frequency f{sub 0} is given by the relationship f{sub 0} = c[(I/a){sup 2} + (m/b){sup 2} + (n/d){sup 2}]{sup 0.5}/2 where a and d are the lengths of the base sides and b is the height of the box in MKS units and c is the velocity of light.

  8. Wall compliance and violin cavity modes.

    Science.gov (United States)

    Bissinger, George

    2003-03-01

    Violin corpus wall compliance, which has a substantial effect on cavity mode frequencies, was added to Shaw's two-degree-of-freedom (2DOF) network model for A0 ("main air") and A1 (lowest length mode included in "main wood") cavity modes. The 2DOF model predicts a V(-0.25) volume dependence for A0 for rigid violin-shaped cavities, to which a semiempirical compliance correction term, V(-x(c)) (optimization parameter x(c)) consistent with cavity acoustical compliance and violin-based scaling was added. Optimizing x(c) over A0 and A1 frequencies measured for a Hutchins-Schelleng violin octet yielded x(c) approximately 0.08. This markedly improved A0 and A1 frequency predictions to within approximately +/- 10% of experiment over a range of about 4.5:1 in length, 10:1 in f-hole area, 3:1 in top plate thickness, and 128:1 in volume. Compliance is a plausible explanation for A1 falling close to the "main wood" resonance, not increasingly higher for the larger instruments, which were scaled successively shorter compared to the violin for ergonomic and practical reasons. Similarly incorporating compliance for A2 and A4 (lowest lower-/upper-bout modes, respectively) improves frequency predictions within +/-20% over the octet.

  9. Lasers with intra-cavity phase elements

    Science.gov (United States)

    Gulses, A. Alkan; Kurtz, Russell; Islas, Gabriel; Anisimov, Igor

    2018-02-01

    Conventional laser resonators yield multimodal output, especially at high powers and short cavity lengths. Since highorder modes exhibit large divergence, it is desirable to suppress them to improve laser quality. Traditionally, such modal discriminations can be achieved by simple apertures that provide absorptive loss for large diameter modes, while allowing the lower orders, such as the fundamental Gaussian, to pass through. However, modal discrimination may not be sufficient for short-cavity lasers, resulting in multimodal operation as well as power loss and overheating in the absorptive part of the aperture. In research to improve laser mode control with minimal energy loss, systematic experiments have been executed using phase-only elements. These were composed of an intra-cavity step function and a diffractive out-coupler made of a computer-generated hologram. The platform was a 15-cm long solid-state laser that employs a neodymium-doped yttrium orthovanadate crystal rod, producing 1064 nm multimodal laser output. The intra-cavity phase elements (PEs) were shown to be highly effective in obtaining beams with reduced M-squared values and increased output powers, yielding improved values of radiance. The utilization of more sophisticated diffractive elements is promising for more difficult laser systems.

  10. A variational computation for coved cavity structure

    International Nuclear Information System (INIS)

    Pan Weimin; Zhou Wenzhen

    1992-01-01

    In order to improve the beam quality and reduce the beam breakup and wake effects caused by the high beam current in electron linac, the coved cavity with big beam hole is used in the world. A variational method is used, and the results are similar to that of Boeing Company

  11. Congenital malformation of inner ear, single cavity

    International Nuclear Information System (INIS)

    Torres Pazmino, Julio Cesar; Marrugo Pardo, Gilberto Eduardo

    2010-01-01

    Congenital malformations of the inner ear are rare conditions, but their detection requires high diagnostic accuracy. In this report we describe the case of a patient with single or common cavity, discuss the corresponding radiological images, describe the treatment of this patient with a cochlear implant, and review the classification and differential diagnosis of the other anomalies of the inner ear.

  12. Quantization of Electromagnetic Fields in Cavities

    Science.gov (United States)

    Kakazu, Kiyotaka; Oshiro, Kazunori

    1996-01-01

    A quantization procedure for the electromagnetic field in a rectangular cavity with perfect conductor walls is presented, where a decomposition formula of the field plays an essential role. All vector mode functions are obtained by using the decomposition. After expanding the field in terms of the vector mode functions, we get the quantized electromagnetic Hamiltonian.

  13. Nonlinear Analysis of Cavities in Rock Salt

    DEFF Research Database (Denmark)

    Ottosen, N. S.; Krenk, Steen

    1979-01-01

    The paper covers some material and computational aspects of the rock mechanics of leached cavities in salt. A material model is presented in which the instantaneous stiffness of the salt is obtained by interpolation between the unloaded state and a relevant failure state. The model enables predic...

  14. Pressurized rf cavities in ionizing beams

    Directory of Open Access Journals (Sweden)

    B. Freemire

    2016-06-01

    Full Text Available A muon collider or Higgs factory requires significant reduction of the six dimensional emittance of the beam prior to acceleration. One method to accomplish this involves building a cooling channel using high pressure gas filled radio frequency cavities. The performance of such a cavity when subjected to an intense particle beam must be investigated before this technology can be validated. To this end, a high pressure gas filled radio frequency (rf test cell was built and placed in a 400 MeV beam line from the Fermilab linac to study the plasma evolution and its effect on the cavity. Hydrogen, deuterium, helium and nitrogen gases were studied. Additionally, sulfur hexafluoride and dry air were used as dopants to aid in the removal of plasma electrons. Measurements were made using a variety of beam intensities, gas pressures, dopant concentrations, and cavity rf electric fields, both with and without a 3 T external solenoidal magnetic field. Energy dissipation per electron-ion pair, electron-ion recombination rates, ion-ion recombination rates, and electron attachment times to SF_{6} and O_{2} were measured.

  15. Plasma Evolution within an Erupting Coronal Cavity

    Science.gov (United States)

    Long, David M.; Harra, Louise K.; Matthews, Sarah A.; Warren, Harry P.; Lee, Kyoung-Sun; Doschek, George A.; Hara, Hirohisa; Jenkins, Jack M.

    2018-03-01

    Coronal cavities have previously been observed to be associated with long-lived quiescent filaments and are thought to correspond to the associated magnetic flux rope. Although the standard flare model predicts a coronal cavity corresponding to the erupting flux rope, these have only been observed using broadband imaging data, restricting an analysis to the plane-of-sky. We present a unique set of spectroscopic observations of an active region filament seen erupting at the solar limb in the extreme ultraviolet. The cavity erupted and expanded rapidly, with the change in rise phase contemporaneous with an increase in nonthermal electron energy flux of the associated flare. Hot and cool filamentary material was observed to rise with the erupting flux rope, disappearing suddenly as the cavity appeared. Although strongly blueshifted plasma continued to be observed flowing from the apex of the erupting flux rope, this outflow soon ceased. These results indicate that the sudden injection of energy from the flare beneath forced the rapid eruption and expansion of the flux rope, driving strong plasma flows, which resulted in the eruption of an under-dense filamentary flux rope.

  16. All-optical tunable photonic crystal cavity

    DEFF Research Database (Denmark)

    Pu, Minhao; Liu, Liu; Ou, Haiyan

    2010-01-01

    We demonstrate an ultra-small photonic crystal cavity with two resonant modes. An all-optical tuning operation based on the free-carrier plasma effect is, for the first time, realized utilizing a continuous wave light source. The termo-optical effect is minimized by isoproponal infiltration...

  17. Direct Numerical Simulation of Driven Cavity Flows

    NARCIS (Netherlands)

    Verstappen, R.; Wissink, J.G.; Veldman, A.E.P.

    Direct numerical simulations of 2D driven cavity flows have been performed. The simulations exhibit that the flow converges to a periodically oscillating state at Re=11,000, and reveal that the dynamics is chaotic at Re=22,000. The dimension of the attractor and the Kolmogorov entropy have been

  18. Characterization and simulation of a pillbox cavity

    CERN Document Server

    Moran Guizan, Carla

    2017-01-01

    A cylindrical pillbox cavity is characterized and its principal parameters, such as the cut-off frequencies of the modes, the quality factor and R/Q figure, are calculated. Additionally, these measurements are compared with an analytical analysis and with a simulation with the software CST Studio to determine how precise they are.

  19. Shear Layer Dynamics in Resonating Cavity Flows

    National Research Council Canada - National Science Library

    Ukeiley, Lawrence

    2004-01-01

    .... The PIV data was also combined with the surface pressure measurements through the application of the Quadratic Stochastic Estimation procedure to provide time resolved snapshots of the flow field. Examination of these results indicate the strong pumping action of the cavity regardless of whether resonance existed and was used to visualize the large scale structures interacting with the aft wall.

  20. Natural convection inside an irregular porous cavity

    International Nuclear Information System (INIS)

    Beltran, Jorge I. LLagostera; Trevisan, Osvair Vidal

    1990-01-01

    Natural convection flow induced by heating from below in a irregular porous cavity is investigated numerically. The influence of the modified Rayleigh number and geometric ratios on heat transfer and fluid flow is studied. Global and local Nusselt for Rayleigh numbers covering the range 0 - 1600 and for several geometric ratios. The fluid flow and the temperature field are illustrated by contour maps. (author)

  1. Accoustic Localization of Breakdown in Radio Frequency Accelerating Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Peter Gwin [IIT, Chicago

    2016-07-01

    Current designs for muon accelerators require high-gradient radio frequency (RF) cavities to be placed in solenoidal magnetic fields. These fields help contain and efficiently reduce the phase space volume of source muons in order to create a usable muon beam for collider and neutrino experiments. In this context and in general, the use of RF cavities in strong magnetic fields has its challenges. It has been found that placing normal conducting RF cavities in strong magnetic fields reduces the threshold at which RF cavity breakdown occurs. To aid the effort to study RF cavity breakdown in magnetic fields, it would be helpful to have a diagnostic tool which can localize the source of breakdown sparks inside the cavity. These sparks generate thermal shocks to small regions of the inner cavity wall that can be detected and localized using microphones attached to the outer cavity surface. Details on RF cavity sound sources as well as the hardware, software, and algorithms used to localize the source of sound emitted from breakdown thermal shocks are presented. In addition, results from simulations and experiments on three RF cavities, namely the Aluminum Mock Cavity, the High-Pressure Cavity, and the Modular Cavity, are also given. These results demonstrate the validity and effectiveness of the described technique for acoustic localization of breakdown.

  2. Cavity Processing and Preparation of 650 MHz Elliptical Cell Cavities for PIP-II

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, Allan [Fermilab; Chandrasekaran, Saravan Kumar [Fermilab; Grassellino, Anna [Fermilab; Melnychuk, Oleksandr [Fermilab; Merio, Margherita [Fermilab; Reid, Thomas [Argonne (main); Sergatskov, Dmitri [Fermilab

    2017-05-01

    The PIP-II project at Fermilab requires fifteen 650 MHz SRF cryomodules as part of the 800 MeV LINAC that will provide a high intensity proton beam to the Fermilab neutrino program. A total of fifty-seven high-performance SRF cavities will populate the cryomodules and will operate in both pulsed and continuous wave modes. These cavities will be processed and prepared for performance testing utilizing adapted cavity processing infrastructure already in place at Fermilab and Argonne. The processing recipes implemented for these structures will incorporate state-of-the art processing and cleaning techniques developed for 1.3 GHz SRF cavities for the ILC, XFEL, and LCLS-II projects. This paper describes the details of the processing recipes and associated chemistry, heat treatment, and cleanroom processes at the Fermilab and Argonne cavity processing facilities. This paper also presents single and multi-cell cavity test results with quality factors above 5·10¹⁰ and accelerating gradients above 30 MV/m.

  3. HOM study and parameter calculation of the TESLA cavity model

    CERN Document Server

    Zeng, Ri-Hua; Gerigk Frank; Wang Guang-Wei; Wegner Rolf; Liu Rong; Schuh Marcel

    2010-01-01

    The Superconducting Proton Linac (SPL) is the project for a superconducting, high current H-accelerator at CERN. To find dangerous higher order modes (HOMs) in the SPL superconducting cavities, simulation and analysis for the cavity model using simulation tools are necessary. The. existing TESLA 9-cell cavity geometry data have been used for the initial construction of the models in HFSS. Monopole, dipole and quadrupole modes have been obtained by applying different symmetry boundaries on various cavity models. In calculation, scripting language in HFSS was used to create scripts to automatically calculate the parameters of modes in these cavity models (these scripts are also available in other cavities with different cell numbers and geometric structures). The results calculated automatically are then compared with the values given in the TESLA paper. The optimized cavity model with the minimum error will be taken as the base for further simulation of the SPL cavities.

  4. Microfabrication of cavities in polydimethylsiloxane using DRIE silicon molds.

    Science.gov (United States)

    Giang, Ut-Binh T; Lee, Dooyoung; King, Michael R; DeLouise, Lisa A

    2007-12-01

    We present a novel method to create cavities in PDMS that is simple and exhibits wide process latitude allowing control over the radius of curvature to form shallow concave pits or deep spherical cavities.

  5. Theory of optical cavity and laser with output coupling

    OpenAIRE

    氏原, 紀公雄

    2006-01-01

    A quantum-mechanical analysis of an optical cavity having output coupling is presented withapplications to the laser theory. The rigorous treatment of the output coupling allows unifiedanalysis of the optical field inside and outside of the cavity. This treatment had lead to a newexpression for the laser line-width that contained the influences of non-uniform oscillating fielddistribution of the real cavity mode as well as the deviation from the cavity field mode due to non-uniformgain satura...

  6. Conceptual design of advanced central receiver power system. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Tracey, T. R.

    1978-09-01

    The design of a 300 MWe tower focus power plant which uses molten salt heat transfer fluids and sensible heat storage is described in detail. The system consists of nine heliostat fields with 7711 heliostats in each. Four cavity receivers are located at the top of a 155-meter tower. Tasks include: (1) review and analysis of preliminary specification; (2) parametric analysis; (3) selection of preferred configuration; (4) commercial plant conceptual design; (5) assessment of commercial-sized advanced central power system; (6) development plan; (7) program plan; (8) reports and data; (9) program management; (10) safety analysis; and (11) material study and test program. (WHK)

  7. Cryogenic cavity detector for a large-scale cold dark-matter axion search

    CERN Document Server

    Peng, H; Daw, E; Golubev, N A; Hagmann, C A; Kinion, D; Laveigne, J; Moltz, D M; Nezrick, F A; Powell, J; Rosenberg, L J; Sikivie, P; Stoeffl, W; Sullivan, N S; Tanner, D B; Turner, M S; Bibber, K V

    2000-01-01

    An axion detector consisting of a tunable high-Q cavity, a superconducting magnet, and a superheterodyne receiver with an ultra-low noise pre-amplifier has been built to search for galactic halo axions in the mass range of 1.3-13 mu eV. The detector instrumentation, search process, and data analysis are described. For the first time, this class of detector has reached sufficient sensitivity to detect halo axions with high confidence.

  8. Solar advanced internal film receiver

    International Nuclear Information System (INIS)

    Torre Cabezas, M. de la

    1990-01-01

    In a Solar Central Internal Film Receiver, the heat absorbing fluid (a molten nitrate salt) flows in a thin film down over the non illuminated side of an absorber panel. Since the molten salt working fluid is not contained in complicated tube manifolds, the receiver design is simples than a conventional tube type-receiver resulting in a lower cost and a more reliable receiver. The Internal Film Receiver can be considered as an alternative to the Direct Absorption Receiver, in the event that the current problems of the last one can not be solved. It also describes here the test facility which will be used for its solar test, and the test plans foreseen. (Author) 17 refs

  9. Communications receivers principles and design

    CERN Document Server

    Rohde, Ulrich L; Zahnd, Hans

    2017-01-01

    This thoroughly updated guide offers comprehensive explanations of the science behind today’s radio receivers along with practical guidance on designing, constructing, and maintaining real-world communications systems. You will explore system planning, antennas and antenna coupling, amplifiers and gain control, filters, mixers, demodulation, digital communication, and the latest software defined radio (SDR) technology. Written by a team of telecommunication experts, Communications Receivers: Principles and Design, Fourth Edition, features technical illustrations, schematic diagrams, and detailed examples. Coverage includes: • Basic radio considerations • Radio receiver characteristics • Receiver system planning • Receiver implementation considerations • RF and baseband techniques for Software-Defined Radios • Transceiver SDR considerations • Antennas and antenna coupling • Mixers • Frequency sources and control • Ancillary receiver circuits • Performance measurement

  10. Scaling of reactor cavity wall loads and stresses

    International Nuclear Information System (INIS)

    Bohachevsky, I.O.

    1977-11-01

    Scalings of reactor cavity wall loads and stresses are determined by deriving an analytic expression in terms of relevant parameters for each loading induced in the reactor cavity walls by fuel pellet microexplosion and by deriving associated expressions relating resulting stresses to shell thicknesses. Also identified are problems that require additional investigations to obtain satisfactory explicit stress estimates for the reactor cavity walls

  11. Diagnostic Role of Neutrophil-Lymphocyte Ratio in Oral Cavity ...

    African Journals Online (AJOL)

    2018-02-07

    Feb 7, 2018 ... Aim: In this study, we aimed to evaluate the diagnostic role of neutrophil– lymphocyte ratio (NLR) and other hemogram parameters in differentiating nonmalignant oral cavity lesions from oral cavity cancers. Methods: Ninety- five patients who were performed oral cavity biopsy between the years 2013 and.

  12. Meeting to discuss laser cavity design for photon linear collider ...

    Indian Academy of Sciences (India)

    The design is fairly insensitive to displacements transverse to the beam but very sensitive to change in length of the cavity (as the power enhancement of the laser cavity is lost). In fact an accuracy of less than 1 nm is required, which implies that adaptive optics are required to maintain the cavity enhancement. Power deposit ...

  13. Decoherence in semiconductor cavity QED systems due to phonon couplings

    DEFF Research Database (Denmark)

    Nielsen, Per Kær; Mørk, Jesper

    2014-01-01

    We investigate the effect of electron-phonon interactions on the coherence properties of single photons emitted from a semiconductor cavity QED (quantum electrodynamics) system, i.e., a quantum dot embedded in an optical cavity. The degree of indistinguishability, governing the quantum mechanical...... diagonalization approach. We find that for large cavity decay rates the perturbation theory may break down....

  14. 21 CFR 872.3250 - Calcium hydroxide cavity liner.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

  15. 21 CFR 872.6030 - Oral cavity abrasive polishing agent.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Oral cavity abrasive polishing agent. 872.6030... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6030 Oral cavity abrasive polishing agent. (a) Identification. An oral cavity abrasive polishing agent is a device in paste or powder form...

  16. Diagnostic Role of Neutrophil-Lymphocyte Ratio in Oral Cavity ...

    African Journals Online (AJOL)

    Aim: In this study, we aimed to evaluate the diagnostic role of neutrophil– lymphocyte ratio (NLR) and other hemogram parameters in differentiating nonmalignant oral cavity lesions from oral cavity cancers. Methods: Ninetyfive patients who were performed oral cavity biopsy between the years 2013 and 2015 were ...

  17. Use of a fiberscope for examining cavity nests

    Science.gov (United States)

    Kathryn L. Purcell

    1997-01-01

    A system is described that uses a fiberscope to view nests in cavities to provide detailed information on eggs and nestlings. The flexible probe can be inserted around bends, and the tip articulates to allow viewing of the entire cavity and nest. A light guide bundle furnishes light to enable viewing of dark cavities and optical fibers transmit the impage from the lens...

  18. BIOREACTOR WITH LID FOR EASY ACCESS TO INCUBATION CAVITY

    DEFF Research Database (Denmark)

    2012-01-01

    There is provided a bioreactor which is provided with a lid (13) that facilitates access to the incubation cavity. Specifically the end wall of the incubation cavity is constituted by the lid (13) so that removal of the cap renders the incubation cavity fully accessible....

  19. Investigation of free air in peritoneal cavity

    International Nuclear Information System (INIS)

    Park, Sam Gyoun; Park, Bok Hwan; Lee, Dong Hoon; Oh, Jang Suk

    1972-01-01

    On the radiographic findings of simple abdomen, detection of free air in peritoneal cavity indicates a perforation of hollow viscus. In general, free air in abdomen indicate perforation of hollow viscus caused by various disease conditions, i.e. perforation of peptic ulcer, ulcerating malignancy, colon diverticulitis and rupture of pneumatosis cystoides intestinale etc., or by trauma, however it can be rarely noticeable in the cases of intraabdominal infection with overgrowth of gas forming organisms. Eighty eight cases of free air in peritoneal cavity were analysed during the period from July, 1970 to August, 1972 at Kyungpook National University Hospital. As shown in the following tables, various clinical findings were analysed; overview of cases, causating factors and location of rupture, and it's seasonal preponderance

  20. Electro Polishing of Niobium Cavities at DESY

    CERN Document Server

    Matheisen, A; Morales, H; Petersen, B; Schmoekel, M; Steinhau-Kühl, N

    2004-01-01

    At DESY a facility for electro polishing (EP) of the super conducting (s.c.) TESLA/TTF cavities have been built and is operational since summer 2003. The EP infrastructure is capable to handle single-cell structures and the standard TESLA/ TTF nine-cell cavities. Several electro polishing processes have been made since and acceleration voltage up to 40 MV/m have been reached in nine cell structures. We report on measurements and experiences gained since 2003 as well as on handling procedures developed for the preparation of electro polished resonators. Specific data like heat production, variation of current density and bath aging will be presented. Another important point for reproducible results is the quality control of the electro polishing process. First quality control steps to be implanted in the EP procedure for large-scale production will be described.

  1. Multipass optical cavity for inverse Compton interactions

    Energy Technology Data Exchange (ETDEWEB)

    Rollason, A.J. E-mail: a.j.rollason@keele.ac.uk; Fang, X.; Dugdale, D.E

    2004-07-01

    The recycling of laser beams in the focal region of non-resonant multipass optical cavities has been investigated as a means of providing a high intensity of photons for weak interaction experiments. Ray-tracing simulations and measurements with an Ar-ion laser have been carried out to examine the intensity profiles of the laser field in different 2-mirror geometries. In particular, the use of such cavities in the generation of X-rays by inverse Compton scattering is considered. X-ray yields are calculated for electron beams of 0.05, 0.1, 0.2 and 0.5 mm diameter yielding enhancement factors of 10-200 compared to a free space laser interaction.

  2. Postirradiation flap infection about the oral cavity

    International Nuclear Information System (INIS)

    Cabbabe, E.B.; Herbold, D.R.; Sunwoo, Y.C.; Baroudi, I.F.

    1983-01-01

    Postirradiation alteration of oral flora is well documented in the literature. Infection as a complication leading to partial or complete loss of a flap used to reconstruct a defect in the oral cavity is a worrisome outcome. We describe how a flap that was judged clinically to be viable became overwhelmingly infected with the Klebsiella oxytoca, an oral cavity pathogen encountered in this patient following irradiation. Local and systemic changes led to detachment of the flap. This complication may be explained, in view of the absence of venous congestion or arterial ischemia both clinically and pathologically, by the proven contamination of the flap by the Klebsiella pathogen. Local factors resulted in lower resistance and subsequent overwhelming infection. Discussion of the case, review of pertinent literature, and proposed solutions are presented

  3. HOM Couplers for CERN SPL Cavities

    CERN Document Server

    Papke, Kai; Van Rienen, U

    2013-01-01

    Higher-Order-Modes (HOMs) may affect beam stability and refrigeration requirements of superconducting proton linacs such as the SPL, which is studied at CERN as the driver for future neutrino facilities. In order to limit beam-induced HOM effects, CERN considers the use of HOM couplers on the cut-off tubes of the 5-cell superconducting cavities. These couplers consist of resonant antennas shaped as loops or probes, which are designed to couple to modes of a specific frequency range. In this paper the design process is presented and a comparison is made between various design options for the medium and high-beta SPL cavities, both operating at 704.4 MHz. The RF characteristics and thermal behaviour of the various designs are discussed.

  4. Tunable Q-Factor RF Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Balcazar, Mario D. [Fermilab; Yonehara, Katsuya [Fermilab; Moretti, Alfred [Fermilab; Kazakevitch, Gregory [Fermilab

    2018-01-01

    Intense neutrino beam is a unique probe for researching beyond the standard model. Fermilab is the main institution to produce the most powerful and widespectrum neutrino beam. From that respective, a radiation robust beam diagnostic system is a critical element in order to maintain the quality of the neutrino beam. Within this context, a novel radiation-resistive beam profile monitor based on a gasfilled RF cavity is proposed. The goal of this measurement is to study a tunable Qfactor RF cavity to determine the accuracy of the RF signal as a function of the quality factor. Specifically, measurement error of the Q-factor in the RF calibration is investigated. Then, the RF system will be improved to minimize signal error.

  5. Investigation of free air in peritoneal cavity

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sam Gyoun; Park, Bok Hwan; Lee, Dong Hoon; Oh, Jang Suk [Kyungpook National University School of Medicine, Taegu (Korea, Republic of)

    1972-12-15

    On the radiographic findings of simple abdomen, detection of free air in peritoneal cavity indicates a perforation of hollow viscus. In general, free air in abdomen indicate perforation of hollow viscus caused by various disease conditions, i.e. perforation of peptic ulcer, ulcerating malignancy, colon diverticulitis and rupture of pneumatosis cystoides intestinale etc., or by trauma, however it can be rarely noticeable in the cases of intraabdominal infection with overgrowth of gas forming organisms. Eighty eight cases of free air in peritoneal cavity were analysed during the period from July, 1970 to August, 1972 at Kyungpook National University Hospital. As shown in the following tables, various clinical findings were analysed; overview of cases, causating factors and location of rupture, and it's seasonal preponderance.

  6. HPV and cancer of the oral cavity.

    Science.gov (United States)

    Hübbers, Christian U; Akgül, Baki

    2015-01-01

    Increased awareness of human papillomavirus (HPV) as an etiological cause of head and neck squamous cell carcinoma has increased the interest in analysis of distinct oral sub-sites. It is currently under debate, whether HPV plays a role in the development of squamous cell carcinoma of the oral cavity (OSCC). The weakness in most published studies is the lack of performing different HPV detection tests combined with analysis for biological activity of the virus. In addition, different sub-sites of the oral cavity had been combined to a single entity, which retrospectively leads to a highly heterogeneous basis of data. In this review we mainly discuss the unclear role of HPV in OSCC development.

  7. Dielectric supported radio-frequency cavities

    Science.gov (United States)

    Yu, David U. L.; Lee, Terry G.

    2000-01-01

    A device which improves the electrical and thermomechanical performance of an RF cavity, for example, in a disk-loaded accelerating structure. A washer made of polycrystalline diamond is brazed in the middle to a copper disk washer and at the outer edge to the plane wave transformer tank wall, thus dissipating heat from the copper disk to the outer tank wall while at the same time providing strong mechanical support to the metal disk. The washer structure eliminates the longitudinal connecting rods and cooling channels used in the currently available cavities, and as a result minimizes problems such as shunt impedance degradation and field distortion in the plane wave transformer, and mechanical deflection and uneven cooling of the disk assembly.

  8. Quantum networks based on cavity QED

    Energy Technology Data Exchange (ETDEWEB)

    Ritter, Stephan; Bochmann, Joerg; Figueroa, Eden; Hahn, Carolin; Kalb, Norbert; Muecke, Martin; Neuzner, Andreas; Noelleke, Christian; Reiserer, Andreas; Uphoff, Manuel; Rempe, Gerhard [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching (Germany)

    2014-07-01

    Quantum repeaters require an efficient interface between stationary quantum memories and flying photons. Single atoms in optical cavities are ideally suited as universal quantum network nodes that are capable of sending, storing, retrieving, and even processing quantum information. We demonstrate this by presenting an elementary version of a quantum network based on two identical nodes in remote, independent laboratories. The reversible exchange of quantum information and the creation of remote entanglement are achieved by exchange of a single photon. Quantum teleportation is implemented using a time-resolved photonic Bell-state measurement. Quantum control over all degrees of freedom of the single atom also allows for the nondestructive detection of flying photons and the implementation of a quantum gate between the spin state of the atom and the polarization of a photon upon its reflection from the cavity. Our approach to quantum networking offers a clear perspective for scalability and provides the essential components for the realization of a quantum repeater.

  9. Dental Sealants Prevent Cavities PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    2016-10-18

    This 60 second public service announcement is based on the October 2016 CDC Vital Signs report. Dental sealants, applied soon after a child's permanent molars come in, can protect against cavities for up to nine years. Applying sealants in schools for low-income children could save millions in dental treatment costs.  Created: 10/18/2016 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 10/18/2016.

  10. Capture cavity II results at FNAL

    Energy Technology Data Exchange (ETDEWEB)

    Branlard, Julien; Chase, Brian; Cancelo, G.; Carcagno, R.; Edwards, H.; Fliller, R.; Hanna, B.; Harms, Elvan; Hocker, A.; Koeth, T.; Kucera, M.; /Fermilab

    2007-06-01

    As part of the research and development towards the International Linear Collider (ILC), several test facilities have been developed at Fermilab. This paper presents the latest Low Level RF (LLRF) results obtained with Capture Cavity II (CCII) at the ILC Test Accelerator (ILCTA) test facility. The main focus will be on controls and RF operations using the SIMCON based LLRF system developed in DESY [1]. Details about hardware upgrades and future work will be discussed.

  11. Single cavity Fabry-Perot modulator enhancements and integrated vertically coupled cavity light-emitting diode

    Science.gov (United States)

    Liu, Daxin

    Fabry-Perot modulators with Multi-Quantum Wells (MQWs) cavities have been studied with great interest during recent years. Usually operating as intensity modulators, these devices have very high modulation contrast ratios, can be operated at very high speed, can be easily made into two dimensional arrays and can be integrated with silicon ICs. They are thus very promising for optical interconnects, optical switching and image processing applications. But before these modulators are to be used in real applications, there are several issues that need to be solved, including the parasitic phase modulation, the bandwidth of such modulators and the alignment of modulator operation wavelength with the wavelength of lasers or light emitting diodes. In this work, the phase properties of Fabry-Perot reflection modulators will be discussed first and an experimental method using a modified Michelson interferometer to characterize the exact phase change will be demonstrated. It is demonstrated that the phase of the reflection light beam from a Fabry-Perot modulator is determined not only by the refractive index change inside the cavity but also by the absorption change inside the cavity. With the purpose of expanding the limited bandwidth of such modulator, devices with short passive cavities are designed and fabricated, the results are described and trade-offs between modulation depth and bandwidth will be discussed. In order to solve the problem of alignment and expand the functionality of Fabry-Perot modulators further, vertically coupled cavity devices with each cavity being electrically controlled independently have been developed. Both a coupled cavity modulator and an integrated light emitting diode with a transmission Fabry-Perot modulator are demonstrated; the first device enhances the modulation bandwidth while the second device has the potential of combining the advantage of high speed operation of MQWs modulators with the long lifetime and low cost of light

  12. Direct Numerical Simulation of Automobile Cavity Tones

    Science.gov (United States)

    Kurbatskii, Konstantin; Tam, Christopher K. W.

    2000-01-01

    The Navier Stokes equation is solved computationally by the Dispersion-Relation-Preserving (DRP) scheme for the flow and acoustic fields associated with a laminar boundary layer flow over an automobile door cavity. In this work, the flow Reynolds number is restricted to R(sub delta*) < 3400; the range of Reynolds number for which laminar flow may be maintained. This investigation focuses on two aspects of the problem, namely, the effect of boundary layer thickness on the cavity tone frequency and intensity and the effect of the size of the computation domain on the accuracy of the numerical simulation. It is found that the tone frequency decreases with an increase in boundary layer thickness. When the boundary layer is thicker than a certain critical value, depending on the flow speed, no tone is emitted by the cavity. Computationally, solutions of aeroacoustics problems are known to be sensitive to the size of the computation domain. Numerical experiments indicate that the use of a small domain could result in normal mode type acoustic oscillations in the entire computation domain leading to an increase in tone frequency and intensity. When the computation domain is expanded so that the boundaries are at least one wavelength away from the noise source, the computed tone frequency and intensity are found to be computation domain size independent.

  13. Quasilinear infiltration from an elliptical cavity

    Science.gov (United States)

    Kuhlman, Kristopher L.; Warrick, Arthur W.

    2008-08-01

    We develop analytic solutions to the linearized steady-state Richards equation for head and total flowrate due to an elliptic cylinder cavity with a specified pressure head boundary condition. They are generalizations of the circular cylinder cavity solutions of Philip [Philip JR. Steady infiltration from circular cylindrical cavities. Soil Sci Soc Am J 1984;48:270-8]. The circular and strip sources are limiting cases of the elliptical cylinder solution, derived for both horizontally- and vertically-aligned ellipses. We give approximate rational polynomial expressions for total flowrate from an elliptical cylinder over a range of sizes and shapes. The exact elliptical solution is in terms of Mathieu functions, which themselves are generalizations of and computed from trigonometric and Bessel functions. The required Mathieu functions are computed from a matrix eigenvector problem, a modern approach that is straightforward to implement using available linear algebra libraries. Although less efficient and potentially less accurate than the iterative continued fraction approach, the matrix approach is simpler to understand and implement and is valid over a wider parameter range.

  14. Coupling superconducting qubits via a cavity bus.

    Science.gov (United States)

    Majer, J; Chow, J M; Gambetta, J M; Koch, Jens; Johnson, B R; Schreier, J A; Frunzio, L; Schuster, D I; Houck, A A; Wallraff, A; Blais, A; Devoret, M H; Girvin, S M; Schoelkopf, R J

    2007-09-27

    Superconducting circuits are promising candidates for constructing quantum bits (qubits) in a quantum computer; single-qubit operations are now routine, and several examples of two-qubit interactions and gates have been demonstrated. These experiments show that two nearby qubits can be readily coupled with local interactions. Performing gate operations between an arbitrary pair of distant qubits is highly desirable for any quantum computer architecture, but has not yet been demonstrated. An efficient way to achieve this goal is to couple the qubits to a 'quantum bus', which distributes quantum information among the qubits. Here we show the implementation of such a quantum bus, using microwave photons confined in a transmission line cavity, to couple two superconducting qubits on opposite sides of a chip. The interaction is mediated by the exchange of virtual rather than real photons, avoiding cavity-induced loss. Using fast control of the qubits to switch the coupling effectively on and off, we demonstrate coherent transfer of quantum states between the qubits. The cavity is also used to perform multiplexed control and measurement of the qubit states. This approach can be expanded to more than two qubits, and is an attractive architecture for quantum information processing on a chip.

  15. Magnetic resonance imaging of syrinx cavity

    International Nuclear Information System (INIS)

    Fukuda, Teruo; Inoue, Yuichi; Nemoto, Yutaka

    1987-01-01

    Syrinx cavity may result from a number of intramedullary tumors or non-neoplastic conditions such as Chiari malformation, trauma and meningitis. The surgical procedure to repair the syrinx is quite different between the cases with spinal cord tumor and without tumor. Therefore, it is important to determine whether syrinx is associated with tumor or not before surgery. We reviewed MR images of 26 cases with syrinx cavity; 20 of which were not associated with tumor (12 Chiari malformation, 5 trauma, 1 meningitis, 1 hydrocephalus, 1 idiopathic) and 6 of which were associated with intramedullary tumor (3 ependymoma, 2 astrocytoma, 1 hemangioendothelioma). The syrinx showed low signal in all 26 cases on T1 weighted images (SE 600/40). All 6 cases with syrinx associated with intramedullary tumor showed high intensity on T2 weighted images (SE 2000/120). On the other hand, the syrinx of 19 of 20 cases with no tumor condition showed reduced intensity on T2 weighted images. Only one post-traumatic small syrinx showed high signal. This was quite different between the cases with spinal cord tumor and without tumor. Therefore, when the syrinx cavity shows high signal on T2 weighted images, an intramedullary tumor is strongly suggested. (author)

  16. Canine oral cavity neoplasias - Brief review

    Directory of Open Access Journals (Sweden)

    João Filipe Requicha

    2015-03-01

    Full Text Available ABSTRACT. Requicha J.F., Pires M. dos A., Albuquerque C.M. & Viegas C.A. [Canine oral cavity neoplasias - Brief review.] Neoplasias da cavidade oral do cão - Breve revisão. Revista Brasileira de Medicina Veterinária, 37(1:41-46, 2015. Faculdade de Medicina Veterinária, Universidade Lusófona de Humanidades e Tecnologias, Campo Grande, 1749-024 Lisboa, Portugal e Department of Veterinary Sciences, School of Agriculture and Veterinary Sciences, University of Trás-os-Montes e Alto Douro, P.O. Box 1013, 5001-801 Vila Real, Portugal. E-mail: jfrequicha@gmail.com Oral proliferative lesions are relatively common in domestic carnivores but, fortunately, a lot of these lesions are benign. The oral cavity is place of 6% of all tumours in dogs, being the sixth most important localization of neoplasias in this specie. The non-odontogenic tumors arise from structures of the oral cavity, except from dental tissue, and they are mostly malignant. Odontogenic tumors are those originated from the dental structures. In the case of tumors of non-odontogenic, will be described the oral papillomatosis, the melanoma, the squamous cell carcinoma, and the fibrosarcoma. Among the odontogenic tumors, the focus will be on the epulides, ameloblastoma, odontoma and dentigerous cysts.

  17. Fundamental tests in Cavity Quantum Electrodynamics

    CERN Multimedia

    CERN. Geneva

    2010-01-01

    At the dawn of quantum physics, Einstein and Bohr had the dream to confine a photon in a box and to use this contraption in order to illustrate the strange laws of the quantum world. Cavity Quantum Electrodynamics has now made this dream real, allowing us to actually achieve in the laboratory variants of the thought experiments of the founding fathers of quantum theory. In our work at Ecole Normale Supérieure, we use a beam of Rydberg atoms to manipulate and probe non-destructively microwave photons trapped in a very high Q superconducting cavity. We realize ideal quantum non-demolition (QND) measurements of photon numbers, observe the radiation quantum jumps due to cavity relaxation and prepare non-classical fields such as Fock and Schrödinger cat states. Combining QND photon counting with a homodyne mixing method, we reconstruct the Wigner functions of these non-classical states and, by taking snapshots of these functions at increasing times, obtain movies of the decoherence process. These experiments ope...

  18. A new awakening for accelerator cavities

    CERN Multimedia

    Katarina Anthony

    2013-01-01

    Imagine: an accelerator unbound by length; one that can bring a beam up to the TeV level in just a few hundred metres. Sounds like a dream? Perhaps not for long. At CERN’s Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE), physicists may soon be working to bring this contemporary fairy-tale to life.   The AWAKE experiment in the CNGS facility. Wherever you find a modern linear particle accelerator, you’ll find with it a lengthy series of RF accelerating cavities. Although based on technology first developed over half a century ago, RF cavities have dominated the accelerating world since their inception. However, new developments in plasma accelerator systems may soon be bringing a new player into the game. By harnessing the power of wakefields generated by beams in plasma cells, physicists may be able to produce accelerator gradients of many GV/m –  hundreds of times higher than those achieved in current RF cavities. “Plasma wakef...

  19. A split-cavity design for the incorporation of a DC bias in a 3D microwave cavity

    NARCIS (Netherlands)

    Cohen, M.A.; Yuan, M.; de Jong, B.W.A.; Beukers, Ewout; Bosman, S.J.; Steele, G.A.

    2017-01-01

    We report on a technique for applying a DC bias in a 3D microwave cavity. We achieve this by isolating the two halves of the cavity with a dielectric and directly using them as DC electrodes. As a proof of concept, we embed a variable capacitance diode in the cavity and tune the resonant

  20. High Gain Advanced GPS Receiver

    National Research Council Canada - National Science Library

    Brown, Alison; Zhang, Gengsheng

    2006-01-01

    NAVSYS High Gain Advanced GPS Receiver (HAGR) uses a digital beam-steering antenna array to enable up to eight GPS satellites to be tracked, each with up to 10 dBi of additional antenna gain over a conventional receiver solution...

  1. Optical single photons on-demand teleported from microwave cavities

    Science.gov (United States)

    Barzanjeh, Sh; Vitali, D.; Tombesi, P.

    2013-03-01

    We propose a scheme for entangling the optical and microwave output modes of the respective cavities by using a micro mechanical resonator. The micro mechanical resonator, on one side, is capacitively coupled to the microwave cavity and, on the other side, it is coupled to a high-finesses optical cavity. We then show how this continuous variable entanglement can be profitably used to teleport the non-Gaussian number state |1> and the superposition (|0\\rangle +|1\\rangle )/\\sqrt 2 from the microwave cavity output mode onto an output of the optical cavity mode with fidelity much larger than the no-cloning limit.

  2. Control of ring lasers by means of coupled cavities

    DEFF Research Database (Denmark)

    Abitan, Haim; Andersen, Ulrik Lund; Skettrup, Torben

    2000-01-01

    Summary form only. Coupling of optical cavities offers a means of controlling the properties of one cavity (e.g. a laser) by making adjustments to another, external cavity. In this contribution we consider a unidirectional ring laser (bow-tie laser) coupled to an external ring cavity. Using...... different configurations we can control the out-coupling from the ring laser thereby influencing the threshold and the circulating power in the different ring cavities. This may be used to obtain the best balance between the passive losses and a nonlinear loss such as e.g. conversion to the second harmonic...... or operation of an optical parametric oscillator....

  3. Geometrically induced surface polaritons in planar nanostructured metallic cavities

    Energy Technology Data Exchange (ETDEWEB)

    Davids, P. S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Intravia, F [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dalvit, Diego A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-01-14

    We examine the modal structure and dispersion of periodically nanostructured planar metallic cavities within the scattering matrix formulation. By nanostructuring a metallic grating in a planar cavity, artificial surface excitations or spoof plasmon modes are induced with dispersion determined by the periodicity and geometric characteristics of the grating. These spoof surface plasmon modes are shown to give rise to new cavity polaritonic modes at short mirror separations that modify the density of modes in nanostructured cavities. The increased modal density of states form cavity polarirons have a large impact on the fluctuation induced electromagnetic forces and enhanced hear transfer at short separations.

  4. Status of the LCLS-II Accelerating Cavity Production

    Energy Technology Data Exchange (ETDEWEB)

    Daly, Ed [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Marhauser, Frank [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Fitzpatrick, Jarrod A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Palczewski, Ari D. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Preble, Joe [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Wilson, Katherine M. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Grimm, C. J. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Burrill, Andrew B. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Gonnella, Daniel [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2017-05-01

    Cavity serial production for the LCLS-II 4 GeV CM SRF linac has started. A quantity of 266 accelerating cavities has been ordered from two industrial vendors. Jefferson Laboratory leads the cavity procurement activities for the project and has successfully transferred the Nitrogen-Doping process to the industrial partners in the initial phase, which is now being applied for the production cavities. We report on the results from vendor qualification and the status of the cavity production for LCLS-II.

  5. Compression Pad Cavity Heating Augmentation on Orion Heat Shield

    Science.gov (United States)

    Hollis, Brian R.

    2011-01-01

    An experimental study has been conducted to assess the effects of compression pad cavities on the aeroheating environment of the Project Orion Crew Exploration Vehicle heat shield. Testing was conducted in Mach 6 and 10 perfect-gas wind tunnels to obtain heating measurements in and around the compression pads cavities using global phosphor thermography. Data were obtained over a wide range of Reynolds numbers that produced laminar, transitional, and turbulent flow within and downstream of the cavities. The effects of cavity dimensions on boundary-layer transition and heating augmentation levels were studied. Correlations were developed for transition onset and for the average cavity-heating augmentation.

  6. Production of superconducting 1.3-GHz cavities for the European X-ray Free Electron Laser

    Science.gov (United States)

    Singer, W.; Brinkmann, A.; Brinkmann, R.; Iversen, J.; Matheisen, A.; Moeller, W.-D.; Navitski, A.; Reschke, D.; Schaffran, J.; Sulimov, A.; Walker, N.; Weise, H.; Michelato, P.; Monaco, L.; Pagani, C.; Wiencek, M.

    2016-09-01

    The production of over 800 1.3-GHz superconducting (SC) cavities for the European X-ray Free Electron Laser (EXFEL), the largest in the history of cavity fabrication, has now been successfully completed. In the past, manufacturing of SC resonators was only partly industrialized; the main challenge for the EXFEL production was transferring the high-performance surface treatment to industry. The production was shared by the two companies RI Research Instruments GmbH (RI) and Ettore Zanon S.p.A. (EZ) on the principle of "build to print". DESY provided the high-purity niobium and NbTi for the resonators. Conformity with the European Pressure Equipment Directive (PED) was developed together with the contracted notified body TUEV NORD. New or upgraded infrastructure has been established at both companies. Series production and delivery of fully-equipped cavities ready for cold rf testing was started in December 2012, and finished in December 2015. More than half the cavities delivered to DESY as specified (referred to "as received") fulfilled the EXFEL specification. Further improvement of low-performing cavities was achieved by supplementary surface treatment at DESY or at the companies. The final achieved average gradient exceeded the EXFEL specification by approximately 25%. In the following paper, experience with the 1.3-GHz cavity production for EXFEL is reported and the main lessons learned are discussed.

  7. UWB delay and multiply receiver

    Energy Technology Data Exchange (ETDEWEB)

    Dallum, Gregory E.; Pratt, Garth C.; Haugen, Peter C.; Romero, Carlos E.

    2013-09-10

    An ultra-wideband (UWB) delay and multiply receiver is formed of a receive antenna; a variable gain attenuator connected to the receive antenna; a signal splitter connected to the variable gain attenuator; a multiplier having one input connected to an undelayed signal from the signal splitter and another input connected to a delayed signal from the signal splitter, the delay between the splitter signals being equal to the spacing between pulses from a transmitter whose pulses are being received by the receive antenna; a peak detection circuit connected to the output of the multiplier and connected to the variable gain attenuator to control the variable gain attenuator to maintain a constant amplitude output from the multiplier; and a digital output circuit connected to the output of the multiplier.

  8. Gas Cavities inside Dust Cavities in Disks Inferred from ALMA Observations

    Science.gov (United States)

    van der Marel, Nienke; van Dishoeck, Ewine F.; Bruderer, Simon; Pinilla, Paola; van Kempen, Tim; Perez, Laura; Isella, Andrea

    2016-01-01

    Protoplanetary disks with cavities in their dust distribution, also named transitional disks, are expected to be in the middle of active evolution and possibly planet formation. In recent years, millimeter-dust rings observed by ALMA have been suggested to have their origin in dust traps, caused by pressure bumps. One of the ways to generate these is by the presence of planets, which lower the gas density along their orbit and create pressure bumps at the edge. We present spatially resolved ALMA Cycle 0 and Cycle 1 observations of CO and CO isotopologues of several famous transitional disks. Gas is found to be present inside the dust cavities, but at a reduced level compared with the gas surface density profile of the outer disk. The dust and gas emission are quantified using the physical-chemical modeling code DALI. In the majority of these disks we find clear evidence for a drop in gas density of at least a factor of 10 inside the cavity, whereas the dust density drops by at least a factor 1000. The CO isotopologue observations reveal that the gas cavities are significantly smaller than the dust cavities. These gas structures suggest clearing by one or more planetary-mass companions.

  9. Rigorous analysis of trapped modes in accelerating cavities

    Directory of Open Access Journals (Sweden)

    Rolf Schuhmann

    2000-12-01

    Full Text Available We report the development of different algorithms for the calculation of quality factors of eigenmodes in accelerating cavities, which have resonance frequencies above the cutoff frequency of the beam tubes. The analysis is based on a discretization of such cavity structures by the finite integration technique, and the radiation at the open boundaries is systematically taken into account by different approaches in time and frequency domain. Results indicate that even single cell cavities of the TESLA type show Q values of 10^{3} and multicell cavities values in excess of 10^{4}. Thus these modes may cause considerable beam instabilities. Comparison with the conventional method of analyzing closed cavities and identifying modes with little change in frequency as a function of boundary condition shows qualitative differences. Some modes from the closed cavity model do not exist in the open structure and thus would be misinterpreted as trapped modes when only a closed cavity analysis is employed.

  10. Radiation-pressure-mediated control of an optomechanical cavity

    Science.gov (United States)

    Cripe, Jonathan; Aggarwal, Nancy; Singh, Robinjeet; Lanza, Robert; Libson, Adam; Yap, Min Jet; Cole, Garrett D.; McClelland, David E.; Mavalvala, Nergis; Corbitt, Thomas

    2018-01-01

    We describe and demonstrate a method to control a detuned movable-mirror Fabry-Pérot cavity using radiation pressure in the presence of a strong optical spring. At frequencies below the optical spring resonance, self-locking of the cavity is achieved intrinsically by the optomechanical (OM) interaction between the cavity field and the movable end mirror. The OM interaction results in a high rigidity and reduced susceptibility of the mirror to external forces. However, due to a finite delay time in the cavity, this enhanced rigidity is accompanied by an antidamping force, which destabilizes the cavity. The cavity is stabilized by applying external feedback in a frequency band around the optical spring resonance. The error signal is sensed in the amplitude quadrature of the transmitted beam with a photodetector. An amplitude modulator in the input path to the cavity modulates the light intensity to provide the stabilizing radiation pressure force.

  11. Multiple cavities in myocardium of left ventricle after irradiation therapy for breast cancer. A case report

    Energy Technology Data Exchange (ETDEWEB)

    Miyake, Shinobu; Kato, Hiroshi; Koizumi, Katsumi [Nishi-Kobe Medical Center (Japan)] (and others)

    1999-09-01

    A 68-year-old woman was admitted to our hospital with congestive heart failure. She had been diagnosed with hypertrophic cardiomyopathy 12 years ago in another hospital. She had received irradiation therapy for left breast cancer 33 years ago after resection of her left breast. Echocardiography revealed left ventricular hypertrophy and wall motion hypokinesis, and multiple cavities in the myocardium of the left ventricle, interventricular septum, and anterior wall. Some cavities were observed to connect to the left ventricular cavity and Doppler echocardiography showed slow velocity flows in them different from that of the coronary artery. The pathologic diagnosis was severe sclerosis of the left coronary artery, especially the left descending artery and its branch, which was the area with irradiation. Histopathology revealed sclerotic changes of the coronary artery causing acute and chronic myocardial infarction, and incomplete regeneration and hypertrophy of cardiac cells. There was no sign of hypertrophic cardiomyopathy. Myocardial degeneration and deciduation were present next to the cavities connected to left ventricle-like fistulas. (author)

  12. Detuning related coupler kick variation of a superconducting nine-cell 1.3 GHz cavity

    Science.gov (United States)

    Hellert, Thorsten; Dohlus, Martin

    2018-04-01

    Superconducting TESLA-type cavities are widely used to accelerate electrons in long bunch trains, such as in high repetition rate free electron lasers. The TESLA cavity is equipped with two higher order mode couplers and a fundamental power coupler (FPC), which break the axial symmetry of the cavity. The passing electrons therefore experience axially asymmetrical coupler kicks, which depend on the transverse beam position at the couplers and the rf phase. The resulting emittance dilution has been studied in detail in the literature. However, the kick induced by the FPC depends explicitly on the ratio of the forward to the backward traveling waves at the coupler, which has received little attention. The intention of this paper is to present the concept of discrete coupler kicks with a novel approach of separating the field disturbances related to the standing wave and a reflection dependent part. Particular attention is directed to the role of the penetration depth of the FPC antenna, which determines the loaded quality factor of the cavity. The developed beam transport model is compared to dedicated experiments at FLASH and European XFEL. Both the observed transverse coupling and detuning related coupler kick variations are in good agreement with the model. Finally, the expected trajectory variations due to coupler kick variations at European XFEL are investigated and results of numerical studies are presented.

  13. A 250 GHz planar low noise Schottky receiver

    Science.gov (United States)

    Ali-Ahmad, Walid Y.; Bishop, William L.; Crowe, Thomas W.; Rebeiz, Gabriel M.

    1993-01-01

    A planar quasi-optical Schottky receiver based on the quasi-integrated horn antenna has been developed and tested over the 230-280 GHz bandwidth. The receiver consists of a planar GaAs Schottky diode placed at the feed of a dipole-probe suspended on a thin dielectric membrane in an etched-pyramidal horn cavity. The diode has a 1.21 micron anode diameter and a low parasitic capacitance due to the use of an etched surface channel. The antenna-mixer results in a measured DSB conversion loss and noise temperature at 258 GHz of 7.2 dB +/- 0.5 dB and 1310 K +/- 70 K, respectively, at room temperature. The design is compatible with SIS mixers, and the low cost of fabrication and simplicity makes it ideal for submillimeter-wave imaging arrays requiring a 10-20 percent bandwidth.

  14. Effects of cavity-cavity interaction on the entanglement dynamics of a generalized double Jaynes-Cummings model

    Science.gov (United States)

    Pandit, Mahasweta; Das, Sreetama; Singha Roy, Sudipto; Shekhar Dhar, Himadri; Sen, Ujjwal

    2018-02-01

    We consider a generalized double Jaynes-Cummings model consisting of two isolated two-level atoms, each contained in a lossless cavity that interact with each other through a controlled photon-hopping mechanism. We analytically show that at low values of such a mediated cavity-cavity interaction, the temporal evolution of entanglement between the atoms, under the effects of cavity perturbation, exhibits the well-known phenomenon of entanglement sudden death (ESD). Interestingly, for moderately large interaction values, a complete preclusion of ESD is achieved, irrespective of its value in the initial atomic state. Our results provide a model to sustain entanglement between two atomic qubits, under the adverse effect of cavity induced perturbation, by introducing a non-intrusive inter-cavity photon exchange that can be physically realized through cavity-QED setups in contemporary experiments.

  15. Solar dynamic heat receiver technology

    Science.gov (United States)

    Sedgwick, Leigh M.

    1991-01-01

    A full-size, solar dynamic heat receiver was designed to meet the requirements specified for electrical power modules on the U.S. Space Station, Freedom. The heat receiver supplies thermal energy to power a heat engine in a closed Brayton cycle using a mixture of helium-xenon gas as the working fluid. The electrical power output of the engine, 25 kW, requires a 100 kW thermal input throughout a 90 minute orbit, including when the spacecraft is eclipsed for up to 36 minutes from the sun. The heat receiver employs an integral thermal energy storage system utilizing the latent heat available through the phase change of a high-temperature salt mixture. A near eutectic mixture of lithium fluoride and calcium difluoride is used as the phase change material. The salt is contained within a felt metal matrix which enhances heat transfer and controls the salt void distribution during solidification. Fabrication of the receiver is complete and it was delivered to NASA for verification testing in a simulated low-Earth-orbit environment. This document reviews the receiver design and describes its fabrication history. The major elements required to operate the receiver during testing are also described.

  16. Solar Pilot Plant, Phase I. Preliminary design report. Volume II, Book 2. Central receiver optical model users manual. CDRL item 2. [HELIAKI code

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-05-01

    HELIAKI is a FORTRAN computer program which simulates the optical/thermal performance of a central receiver solar thermal power plant for the dynamic conversion of solar-generated heat to electricity. The solar power plant which this program simulates consists of a field of individual sun tracking mirror units, or heliostats, redirecting sunlight into a cavity, called the receiver, mounted atop a tower. The program calculates the power retained by that cavity receiver at any point in time or the energy into the receiver over a year's time using a Monte Carlo ray trace technique to solve the multiple integral equations. An artist's concept of this plant is shown.

  17. LTCC-Based Highly Integrated Millimeter-Wave Receiver Front-End Module

    Science.gov (United States)

    Xia, Lei; Xu, Ruimin; Yan, Bo

    2006-07-01

    This paper presents the design and fabrication of a highly integrated Low Temperature Co-fired Ceramic (LTCC) receiver front-end module. This LTCC module is a dual channel receiver module, works at Ka-band, and fabricated including six Ferro A6M dielectric layers and five metal layers, contains eight embedded resistors and eight MMICs. All MMICs are mounted into pre-making cavities on the top surface of the LTCC substrate. Three slot coupled waveguide-to-microstrip transitions are integrated at LTCC substrate to realize RF and LO signal input. The developed module is highly integrated and reliable, which has a compact size of 58 × 50 × 22 mm3 (including the metal cavity). Each channel of the receiver has the noise figure of less than 9 dB and the gain of more than 24 dB at Ka-band.

  18. Elliptical superconducting RF cavities for FRIB energy upgrade

    Science.gov (United States)

    Ostroumov, P. N.; Contreras, C.; Plastun, A. S.; Rathke, J.; Schultheiss, T.; Taylor, A.; Wei, J.; Xu, M.; Xu, T.; Zhao, Q.; Gonin, I. V.; Khabiboulline, T.; Pischalnikov, Y.; Yakovlev, V. P.

    2018-04-01

    The multi-physics design of a five cell, βG = 0 . 61, 644 MHz superconducting elliptical cavity being developed for an energy upgrade in the Facility for Rare Isotope Beams (FRIB) is presented. The FRIB energy upgrade from 200 MeV/u to 400 MeV/u for heaviest uranium ions will increase the intensities of rare isotope beams by nearly an order of magnitude. After studying three different frequencies, 1288 MHz, 805 MHz, and 644 MHz, the 644 MHz cavity was shown to provide the highest energy gain per cavity for both uranium and protons. The FRIB upgrade will include 11 cryomodules containing 5 cavities each and installed in 80-meter available space in the tunnel. The cavity development included extensive multi-physics optimization, mechanical and engineering analysis. The development of a niobium cavity is complete and two cavities are being fabricated in industry. The detailed design of the cavity sub-systems such as fundamental power coupler and dynamic tuner are currently being pursued. In the overall design of the cavity and its sub-systems we extensively applied experience gained during the development of 650 MHz low-beta cavities at Fermi National Accelerator Laboratory (FNAL) for the Proton Improvement Plan (PIP) II.

  19. Photoprocesses of photosensitizing drugs within cyclodextrin cavities.

    Science.gov (United States)

    Monti, Sandra; Sortino, Salvatore

    2002-09-01

    Recently some interest has been focused on the photobehavior of CD-drug inclusion complexes in relation to the problem of the biological photosensitization by drugs. This review is dedicated to the illustration of the mechanistic aspects of the photoprocesses occurring in some non-steroidal anti-inflammatory drugs (NSAIDs), with photosensitising side effects, within CD cavities. It is shown how the photobehavior of the CD-drug associates can help to model the photoreactivity of the drugs in biological sites. The limitations for the use of CDs as protective systems for the clinical administration of photosensitising drugs is also evidenced.

  20. Criteria for vacuum breakdown in rf cavities

    International Nuclear Information System (INIS)

    Peter, W.; Faehl, R.J.; Kadish, A.; Thode, L.E.

    1983-01-01

    A new high-voltage scaling based on Kilpatrick's criterion is presented that suggests that voltages more than twice the Kilpatrick limit can be obtained with identical initial conditions of vacuum and surface cleanliness. The calculations are based on the experimentally observed decrease in secondary electron emission with increasing ion-impact energy above 100 keV. A generalized secondary-emission package has been developed to simulate actual cavity dynamics in conjunction with our 2 1/2-dimensional fully electromagnetic particle-in-cell code CEMIT. The results are discussed with application to the suppression of vacuum breakdown in rf accelerator devices

  1. Wave Dynamical Chaos in Superconducting Microwave Cavities

    CERN Document Server

    Rehfeld, H; Dembowski, C; Gräf, H D; Hofferbert, R; Richter, A; Lengeler, Herbert

    1997-01-01

    During the last few years we have studied the chaotic behavior of special Euclidian geometries, so-called billiards, from the quantum or in more general sense "wave dynamical" point of view. Due to the equivalence between the stationary Schroedinger equation and the classical Helmholtz equation in the two-dimensional case (plain billiards), it is possible to simulate "quantum chaos" with the help of macroscopic, superconducting microwave cavities. Using this technique we investigated spectra of three billiards from the family of Pascal's Snails (Robnik-Billiards) with a different chaoticity in each case in order to test predictions of standard stochastical models for classical chaotic systems.

  2. Giant Submandibular Calculus Eroding Oral Cavity Mucosa

    Directory of Open Access Journals (Sweden)

    Eng Haw Lim

    2017-09-01

    Full Text Available Sialolithiasis is the formation of calculi or sialoliths in the salivary gland. It is the most common benign condition of the salivary gland. Sialolithiasis can occur in all salivary glands. The submandibular gland is most commonly affected followed by the parotid gland. Calculi commonly measure less than 10 mm. Calculi of more than 15 mm are termed giant salivary gland calculi and are infrequently reported in the literature. Here, we report a case of unusually large submandibular gland calculus of 5 cm in greatest dimension which caused erosion of the oral cavity.

  3. Fiberoptic microphone using a polymeric cavity

    Science.gov (United States)

    Wang, Wei-Chih; Soetanto, William; Gu, Kebin

    2011-04-01

    The fabrication and experimental investigation of a fiberoptic microphone is described. The sensing element is a silicon diaphragm with gold thin film coating that is positioned inside a silicone rubber mold at the end of a single mode optical fiber. Thus, a Fabry-Perot interferometer is formed between the inner fiber and the diaphragm. An acoustic pressure change is detected by using the developed microphone. The polymeric cavity and silicon diaphragm-based system exhibits excellent physicochemical properties with a small, simple, low cost, and lightweight design. The system is also electromagnetic interference / radio frequency interference immunity due to the use of fiberoptics.

  4. Giant Submandibular Calculus Eroding Oral Cavity Mucosa.

    Science.gov (United States)

    Lim, Eng Haw; Nadarajah, Sanjeevan; Mohamad, Irfan

    2017-09-01

    Sialolithiasis is the formation of calculi or sialoliths in the salivary gland. It is the most common benign condition of the salivary gland. Sialolithiasis can occur in all salivary glands. The submandibular gland is most commonly affected followed by the parotid gland. Calculi commonly measure less than 10 mm. Calculi of more than 15 mm are termed giant salivary gland calculi and are infrequently reported in the literature. Here, we report a case of unusually large submandibular gland calculus of 5 cm in greatest dimension which caused erosion of the oral cavity.

  5. Intra-cavity vortex beam generation

    CSIR Research Space (South Africa)

    Naidoo, Darryl

    2011-08-01

    Full Text Available in Fig. 3. For a Gaussian pump beam (Fig. 4(a)) we achieved a Gaussian output (Fig. 4(b)) and for a ring shaped pump beam (Fig. 4(c)) we achieved a LG01 (Fig. 4(d)) eigenmode of pure modal quality. The idea of pump shaping is employed to a plano... plano-concave laser cavity with a ring shaped pump intensity profile. The beam shaping element could be removed to revert back to the Gaussian pump scenario. Proc. of SPIE Vol. 8130 813009-4 Downloaded from SPIE Digital Library on 30 Sep 2011...

  6. Interacting collective modes in a laser cavity

    International Nuclear Information System (INIS)

    Graca, E.L.; Brito, A.L. de; Baseia, B.

    1985-01-01

    Collective operators are defined for the quantized radiation field in a one-dimensional laser cavity coupled to a semi-infinite outside region and the overlaps of neighbouring collective modes are considered to show how they modify, in the linear appoximation, the time evolution of the radiation field below threshold. The model and procedure work directly within a continuous spectrum of modes and allow us to get an improved insight on the prescription for the laser field in single-mode operation. (Author) [pt

  7. Cavity enhanced rephased amplified spontaneous emission

    International Nuclear Information System (INIS)

    A Williamson, Lewis; J Longdell, Jevon

    2014-01-01

    Amplified spontaneous emission is usually treated as an incoherent noise process. Recent theoretical and experimental work using rephasing optical pulses has shown that rephased amplified spontaneous emission (RASE) is a potential source of wide bandwidth time-delayed entanglement. Due to poor echo efficiency the plain RASE protocol does not in theory achieve perfect entanglement. Experiments done to date show a very small amount of entanglement at best. Here we show that RASE can, in principle, produce perfect multimode time-delayed two mode squeezing when the active medium is placed inside a Q-switched cavity. (paper)

  8. Superconducting RF Cavities Past, Present and Future

    CERN Document Server

    Chiaveri, Enrico

    2003-01-01

    In the last two decades many laboratories around the world, notably Argonne (ANL), TJNAF (formerly CEBAF), CERN, DESY and KEK, decided to develop the technology of superconducting (SC) accelerating cavities. The aim was either to increase the accelerator energy or to save electrical consumption or both. This technology has been used extensively in the operating machines showing good performances and strong reliability. At present, the technology using bulk niobium (Nb) or Nb coated on copper (Cu) is mature enough to be applied for many different applications, such as synchrotron light sources and spallation neutron drivers. Results, R&D work and future projects will be presented with emphasis on application to linear accelerators.

  9. A Rare Tumor of Nasal Cavity: Glomangiopericytoma

    Directory of Open Access Journals (Sweden)

    Aysegul Verim

    2014-01-01

    Full Text Available Glomangiopericytoma is a rare vascular neoplasm characterized by a pattern of prominent perivascular growth. A 72-year-old woman was admitted to our clinic complaining of nasal obstruction, frequent epistaxis, and facial pain. A reddish tumor filling the left nasal cavity was observed on endoscopy and treated with endoscopic excision. Microscopically, closely packed cells interspersed with numerous thin-walled, branching staghorn vessels were seen. Glomangiopericytoma is categorized as a borderline low malignancy tumor by WHO classification. Long-term follow-up with systemic examination is necessary due to high risk of recurrence.

  10. Different optical properties in different periodic slot cavity geometrical morphologies

    Science.gov (United States)

    Zhou, Jing; Shen, Meng; Du, Lan; Deng, Caisong; Ni, Haibin; Wang, Ming

    2016-09-01

    In this paper, optical properties of two-dimensional periodic annular slot cavity arrays in hexagonal close-packing on a silica substrate are theoretically characterized by finite difference time domain (FDTD) simulation method. By simulating reflectance spectra, electric field distribution, and charge distribution, we confirm that multiple cylindrical surface plasmon resonances can be excited in annular inclined slot cavities by linearly polarized light, in which the four reflectance dips are attributed to Fabry-Perot cavity resonances in the coaxial cavity. A coaxial waveguide mode TE11 will exist in these annular cavities, and the wavelengths of these reflectance dips are effectively tailored by changing the geometrical pattern of slot cavity and the dielectric materials filled in the cavities. These resonant wavelengths are localized in annular cavities with large electric field enhancement and dissipate gradually due to metal loss. The formation of an absorption peak can be explained from the aspect of phase matching conditions. We observed that the proposed structure can be tuned over the broad spectral range of 600-4000 nm by changing the outer and inner radii of the annular gaps, gap surface topography. Meanwhile, different lengths of the cavity may cause the shift of resonance dips. Also, we study the field enhancement at different vertical locations of the slit. In addition, dielectric materials filling in the annular gaps will result in a shift of the resonance wavelengths, which make the annular cavities good candidates for refractive index sensors. The refractive index sensitivity of annular cavities can also be tuned by the geometry size and the media around the cavity. Annular cavities with novel applications can be implied as surface enhanced Raman spectra substrates, refractive index sensors, nano-lasers, and optical trappers. Project supported by the National Natural Science Foundation of China (Grant No. 61178044), the Natural Science Foundation

  11. Progress on SCRF cavity manufacturing activities at RRCAT

    International Nuclear Information System (INIS)

    Puntambekar, A.; Dwivedi, J.; Mundra, G.; Srivastava, P.; Joshi, S.C.; Gupta, P.D.

    2015-01-01

    The work on development of SCRF cavities and associated technologies is ongoing at RRCAT to support its upcoming projects involving SC LINAC. RRCAT is also a member of Indian Institution Fermilab Collaboration (IIFC) working on development of SCRF cavities and associated technologies. Subsequent to 1.3 GHz single cell SCRF cavities, a 650 MHz single cell, a 1.3 GHz five cell and a 1.3 GHz nine cell SCRF cavities have been fabricated. These were tested for their mechanical, vacuum and RF qualifications at RRCAT for pre qualifications. The 1.3 GHz five cell SCRF cavity and 650 MHz single cell SCRF cavity has been processed and successfully tested at Fermi lab under IIFC. The 1.3 GHz five-cell cavity has achieved E acc of 20.3 MV/m at 2 K and 42 MV/m at 1.5-1.7 K with Q o of 2 x 10 10 . The 650 MHz single cell cavity has achieved the E acc > 19.3 MV/m with Q> 4x 10 10 at 2K. A 15 kW Electron Beam Welding (EBW) Machine has also been installed and commissioned at RRCAT as part of special infrastructure for development of SCRF cavities. One each 1.3 GHz and 650 MHz single cell SCRF cavities have also been fabricated using this EBW facility. Present focus of work is towards development of 650 MHz (β=0.92) multi-cell SCRF cavities. This paper will present the various technology development efforts on SCRF cavity fabrication, cavity test results and future plans. (author)

  12. HIGH-EFFICIENCY INFRARED RECEIVER

    Directory of Open Access Journals (Sweden)

    A. K. Esman

    2016-01-01

    Full Text Available Recent research and development show promising use of high-performance solid-state receivers of the electromagnetic radiation. These receivers are based on the low-barrier Schottky diodes. The approach to the design of the receivers on the basis of delta-doped low-barrier Schottky diodes with beam leads without bias is especially actively developing because for uncooled receivers of the microwave radiation these diodes have virtually no competition. The purpose of this work is to improve the main parameters and characteristics that determine the practical relevance of the receivers of mid-infrared electromagnetic radiation at the operating room temperature by modifying the electrodes configuration of the diode and optimizing the distance between them. Proposed original design solution of the integrated receiver of mid-infrared radiation on the basis of the low-barrier Schottky diodes with beam leads allows to effectively adjust its main parameters and characteristics. Simulation of the electromagnetic characteristics of the proposed receiver by using the software package HFSS with the basic algorithm of a finite element method which implemented to calculate the behavior of electromagnetic fields on an arbitrary geometry with a predetermined material properties have shown that when the inner parts of the electrodes of the low-barrier Schottky diode is performed in the concentric elliptical convex-concave shape, it can be reduce the reflection losses to -57.75 dB and the standing wave ratio to 1.003 while increasing the directivity up to 23 at a wavelength of 6.09 μm. At this time, the rounded radii of the inner parts of the anode and cathode electrodes are equal 212 nm and 318 nm respectively and the gap setting between them is 106 nm. These parameters will improve the efficiency of the developed infrared optical-promising and electronic equipment for various purposes intended for work in the mid-infrared wavelength range. 

  13. A tunable waveguide to cavity coupler for high power accelerator cavities

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rajesh, E-mail: krajesh@barc.gov.in [LEHIPA, Physics Group, Bhabha Atomic Research Centre, Mumbai 400085 (India); Singh, P. [LEHIPA, Physics Group, Bhabha Atomic Research Centre, Mumbai 400085 (India); Unnikrishnan, Divya; Kumar, Girish [Department of Electrical Engineering, IIT Bombay, Mumbai 400076 (India)

    2012-02-01

    The end iris ridge waveguide couplers are used to couple power to accelerator cavities through a reduced size coupling port. However, higher electric and magnetic fields due to reduced size lead to strict requirements on dimensional tolerances during coupler fabrication process. It is shown by detailed parametric analysis that even small dimensional changes during manufacturing or operation can lead to undesired shift in design frequency and deterioration of return loss. Hence, transmitted power testing of two couplers connected back to back without an intermediate cavity cannot be carried out. Here, we propose cylindrical static tuners on impedance matching section to relax the dimensional tolerance requirements. It is also shown that an iris coupled coupler-cavity system is more tolerant towards coupler dimensional changes than a stand-alone coupler. However, same tuners can find use for tuning the coupling coefficient of coupler-cavity system. The proposed tuning scheme is expected to reduce the coupler manufacturing costs and provide an useful alternative for coupling coefficient tuning over iris machining.

  14. PPM Receiver Implemented in Software

    Science.gov (United States)

    Gray, Andrew; Kang, Edward; Lay, Norman; Vilnrotter, Victor; Srinivasan, Meera; Lee, Clement

    2010-01-01

    A computer program has been written as a tool for developing optical pulse-position- modulation (PPM) receivers in which photodetector outputs are fed to analog-to-digital converters (ADCs) and all subsequent signal processing is performed digitally. The program can be used, for example, to simulate an all-digital version of the PPM receiver described in Parallel Processing of Broad-Band PPM Signals (NPO-40711), which appears elsewhere in this issue of NASA Tech Briefs. The program can also be translated into a design for digital PPM receiver hardware. The most notable innovation embodied in the software and the underlying PPM-reception concept is a digital processing subsystem that performs synchronization of PPM time slots, even though the digital processing is, itself, asynchronous in the sense that no attempt is made to synchronize it with the incoming optical signal a priori and there is no feedback to analog signal processing subsystems or ADCs. Functions performed by the software receiver include time-slot synchronization, symbol synchronization, coding preprocessing, and diagnostic functions. The program is written in the MATLAB and Simulink software system. The software receiver is highly parameterized and, hence, programmable: for example, slot- and symbol-synchronization filters have programmable bandwidths.

  15. Development of oral cavity inspecting system

    Science.gov (United States)

    Zhang, Hongxia; Wu, Di; Jia, Dagong; Zhang, Yimo

    2009-11-01

    An oral cavity inspecting system is designed and developed to inspect the detail of teeth. The inspecting system is composed of microscopic imaging part, illuminating part, image capture and processing, display part. The two groups of cemented lenses were optimized to minimize the optical aberration and the collimated beam light is gotten between the two lenses. A relay lens is adopted to allow the probe to access the oral cavity depth. The illumination optic fiber is used and the brightness and color temperature can be adjustable. The illumination fiber end surface is oblique cut and the optimum angle is 37°. The image of teeth is imaged on CMOS and captured into computer. The illumination intensity and uniformity were tested and the proper parameter is set. Foucault chart was observed and the system resolution is higher than 100lp/mm. The oral inspecting system is used to test standard tooth model and patho-teeth model. The tooth image is clear and the details can be observed. The experimental results show that the system could meet dental medical application requirements.

  16. Polarization dynamics of VCSELs in external cavities

    Science.gov (United States)

    Marconi, M.; Javaloyes, J.; Barland, S.; Balle, S.; Giudici, M.

    2014-05-01

    We review the dynamics of VCSELs that experience both Polarization-Selective Feedback (PSF) and Crossed- Polarization Reinjection (XPR). Different regimes of regular pulsation were found. For strong enough XPR levels, the VCSEL emission in each of its linearly-polarized components displays a square-wave modulation which regularity is greatly enhanced by small levels of PSF. Such a square-wave is in antiphase for the two polarizations, and it turns out to be stable and robust over broad intervals of current. The frequency of the square-wave is determined by the length of the XPR arm. For weak levels of PSF and XPR, the VCSEL emits a regular train of short optical pulses arising from the locking of the modes in the PSF cavity. The frequency of the pulse train is stable on short time scales, but it wanders with a characteristic time scale of hundreds of roundtrips in the PSF cavity. The experimental results are successfully explained by an extension of the Spin-Flip Model that incorporates gain saturation and the effects of PSF and XPR.

  17. VERY HIGH RESOLUTION RF CAVITY BPM

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Marc C

    2003-05-27

    Linear collider (LC) interaction region beam sizes and component position stability requirements are expected to be a few nanometers[1]. It is important to show that the related tolerances can be achieved, with an electron beam if possible. Using recently developed component stabilization technology, very high-resolution beam position monitors (BPM's), and the ultra-low emittance beam at the KEK ATF, we plan to demonstrate the required stabilization. Our first step is to develop high-resolution RF cavity beam position monitors, using either C or X band frequencies. A C-band cavity BPM with a resolution of 25 nm has been reported in tests at FFTB [2]. By correcting for the effects of non-axial trajectories and using both position and angle BPM movers, we expect to be able to demonstrate a resolution of 2 to 3 nm over a dynamic range of {+-} 20 {micro}m. We report on the progress of the tests here.

  18. Cavity Microwave Searches for Cosmological Axions

    Energy Technology Data Exchange (ETDEWEB)

    Carosi, G; van Bibber, K

    2007-01-22

    This chapter will cover the search for dark matter axions based on microwave cavity experiments proposed by Pierre Sikivie. We will start with a brief overview of halo dark matter and the axion as a candidate. The principle of resonant conversion of axions in an external magnetic field will be described as well as practical considerations in optimizing the experiment as a signal-to-noise problem. A major focus of this chapter will be the two complementary strategies for ultra-low noise detection of the microwave photons--the 'photon-as-wave' approach (i.e. conventional heterojunction amplifiers and soon to be quantum-limited SQUID devices), and 'photon-as-particle' (i.e. Rydberg-atom single-quantum detection). Experimental results will be presented; these experiments have already reached well into the range of sensitivity to exclude plausible axion models, for limited ranges of mass. The section will conclude with a discussion of future plans and challenges for the microwave cavity experiment.

  19. Status of superconducting RF cavity development

    International Nuclear Information System (INIS)

    Shepard, K.W.

    1989-01-01

    For several reasons, a brief historical review seems appropriate at this time. The twenty-fifth anniversary of the first acceleration of beam with a superconducting cavity will occur shortly [1,2,3]. Also, the scope of accelerator applications of superconducting radio-frequency (SRF) devices has, within the last few months, begun to increase rapidly [4] - to the point that it seems likely that early expectations for this technology will largely be fulfilled. Since the object is to accelerate beam, a simple one parameter measure of the technology is the total of how much beam has been accelerated. Figure 1 shows the total accumulated voltage in tests and/or operation of superconducting accelerating cavities with beam, up to the time indicated, as reported in the open literature [4-35]. This parameter has been divided into two terms: first, the subtotal for electron accelerating velocity-of-light structures, and second the subtotal for low-velocity, ion accelerating structures. To restate: each of these terms represents as a function of time an integrated, accumulative total voltage produced by SRF hardware and demonstrated with beam. 56 refs., 4 figs

  20. Porous photonic crystal external cavity laser biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Qinglan [Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Peh, Jessie; Hergenrother, Paul J. [Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Cunningham, Brian T. [Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

    2016-08-15

    We report the design, fabrication, and testing of a photonic crystal (PC) biosensor structure that incorporates a porous high refractive index TiO{sub 2} dielectric film that enables immobilization of capture proteins within an enhanced surface-area volume that spatially overlaps with the regions of resonant electromagnetic fields where biomolecular binding can produce the greatest shifts in photonic crystal resonant wavelength. Despite the nanoscale porosity of the sensor structure, the PC slab exhibits narrowband and high efficiency resonant reflection, enabling the structure to serve as a wavelength-tunable element of an external cavity laser. In the context of sensing small molecule interactions with much larger immobilized proteins, we demonstrate that the porous structure provides 3.7× larger biosensor signals than an equivalent nonporous structure, while the external cavity laser (ECL) detection method provides capability for sensing picometer-scale shifts in the PC resonant wavelength caused by small molecule binding. The porous ECL achieves a record high figure of merit for label-free optical biosensors.

  1. Cavity plasmon polaritons in monolayer graphene

    International Nuclear Information System (INIS)

    Kotov, O.V.; Lozovik, Yu.E.

    2011-01-01

    Plasmon polaritons in a new system, a monolayer doped graphene embedded in optical microcavity, are studied here. The dispersion law for lower and upper cavity plasmon polaritons is obtained. Peculiarities of Rabi splitting for the system are analyzed; particularly, role of Dirac-like spinor (envelope) wave functions in graphene and corresponding angle factors are considered. Typical Rabi frequencies for maximal (acceptable for Dirac-like electron spectra) Fermi energy and frequencies of polaritons near polariton gap are estimated. The plasmon polaritons in considered system can be used for high-speed information transfer in the THz region. -- Highlights: → Plasmon polaritons in a monolayer doped graphene embedded in optical microcavity, are studied here. → The dispersion law for lower and upper cavity plasmon polaritons is obtained. → Peculiarities of Rabi splitting for the system are analyzed. → Role of Dirac-like wave functions in graphene and corresponding angle factors are considered. → Typical Rabi frequencies and frequencies of polaritons near polariton gap are estimated.

  2. Superconducting accelerating cavity for KEK B-factory

    International Nuclear Information System (INIS)

    Furuya, T.; Asano, K.; Mitsunobu, S.; Tajima, T.; Takahashi, T.; Ishi, Y.; Kijima, Y.; Murai, T.; Sennyu, K.

    1996-01-01

    KEKB is an asymmetric collider of 3.5 GeV x 8 GeV with the circulating beams of 2.6 A(e - ) and 1.1 A(e + ). These high currents require the RF cavities which have sufficiently damped higher order modes (HOMs), because RF cavities are the main source of the ring impedance that can cause the single bunch and coupled bunch instabilities. Another problem is a multibunch instability due to the accelerating mode. Two types of accelerating cavities are under development for the RF system of KEKB: a new normal conducting cavity (ARES) and a superconducting (SC) cavity. In this paper, recent activity of an SC accelerating cavity for KEKB is reported. (K.A.)

  3. Optical cavity cooling of mechanical modes of a semiconductor nanomembrane

    DEFF Research Database (Denmark)

    Usami, Koji; Naesby, A.; Bagci, Tolga

    2012-01-01

    Mechanical oscillators can be optically cooled using a technique known as optical-cavity back-action. Cooling of composite metal–semiconductor mirrors, dielectric mirrors and dielectric membranes has been demonstrated. Here we report cavity cooling of mechanical modes in a high-quality-factor and......Mechanical oscillators can be optically cooled using a technique known as optical-cavity back-action. Cooling of composite metal–semiconductor mirrors, dielectric mirrors and dielectric membranes has been demonstrated. Here we report cavity cooling of mechanical modes in a high......-quality-factor and optically active semiconductor nanomembrane. The cooling is a result of electron–hole generation by cavity photons. Consequently, the cooling factor depends on the optical wavelength, varies drastically in the vicinity of the semiconductor bandgap, and follows the excitonic absorption behaviour...... an alternative cooling mechanism that is a result of electronic stress via the deformation potential, and outline future directions for cavity optomechanics with optically active semiconductors....

  4. Construction of 714 MHz HOM-free accelerating cavities.

    Science.gov (United States)

    Sakanaka, S; Hinode, F; Kubo, K; Urakawa, J

    1998-05-01

    A new 'higher-order-mode (HOM)-free' accelerating cavity has been developed which can provide an accelerating voltage of more than 400 kV per cavity at a frequency of 714 MHz. The harmful HOMs in the cavities, which can induce beam instabilities at high beam currents, were heavily damped by using four special waveguide ports and broadband microwave loads. Two cavities of this design were installed in the 1.54 GeV accelerator test facility (ATF) damping ring at KEK, and successfully stored beams. This cavity will also be very useful for synchrotron light sources. The basic design, characteristics of HOMs and construction of this cavity are reported.

  5. 17 GHz photonic band gap cavity with improved input coupling

    Directory of Open Access Journals (Sweden)

    M. A. Shapiro

    2001-04-01

    Full Text Available We present the theoretical design and cold test of a 17 GHz photonic band gap (PBG cavity with improved coupling from an external rectangular waveguide. The PBG cavity is made of a triangular lattice of metal rods with a defect (missing rod in the center. The TM_{010}-like defect mode was chosen as the operating mode. Experimental results are presented demonstrating that critical coupling into the cavity can be achieved by partial withdrawal or removal of some rods from the lattice, a result that agrees with simulations. A detailed design of the PBG accelerator structure is compared with a conventional (pillbox cavity. One advantage of the PBG cavity is that its resonance frequency is much less perturbed by the input/output coupling structure than in a comparable pillbox cavity. The PBG structure is attractive for future accelerator applications.

  6. Quantum noise interference and backaction cooling in cavity nanomechanics.

    Science.gov (United States)

    Elste, Florian; Girvin, S M; Clerk, A A

    2009-05-22

    We present a theoretical analysis of a novel cavity electromechanical system where a mechanical resonator directly modulates the damping rate kappa of a driven electromagnetic cavity. We show that via a destructive interference of quantum noise, the driven cavity can effectively act like a zero-temperature bath irrespective of the ratio kappa/omega_{M}, where omega_{M} is the mechanical frequency. This scheme thus allows one to cool the mechanical resonator to its ground state without requiring the cavity to be in the so-called good cavity limit kappa < omega_{M}. The system described here could be implemented directly using setups similar to those used in recent experiments in cavity electromechanics.

  7. RF kicker cavity to increase control in common transport lines

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, David R.; Ament, Lucas J. P.

    2017-04-18

    A method of controlling e-beam transport where electron bunches with different characteristics travel through the same beam pipe. An RF kicker cavity is added at the beginning of the common transport pipe or at various locations along the common transport path to achieve independent control of different bunch types. RF energy is applied by the kicker cavity kicks some portion of the electron bunches, separating the bunches in phase space to allow independent control via optics, or separating bunches into different beam pipes. The RF kicker cavity is operated at a specific frequency to enable kicking of different types of bunches in different directions. The phase of the cavity is set such that the selected type of bunch passes through the cavity when the RF field is at a node, leaving that type of bunch unaffected. Beam optics may be added downstream of the kicker cavity to cause a further separation in phase space.

  8. 201 MHz Cavity R and D for MUCOOL and MICE

    International Nuclear Information System (INIS)

    Li, Derun; Virostek, Steve; Zisman, Michael; Norem, Jim; Bross, Alan; Moretti, Alfred; Norris, Barry; Torun, Yagmur; Phillips, Larry; Rimmer, Robert; Stirbet, Mircea; Reep, Michael; Summers, Don

    2006-01-01

    We describe the design, fabrication, analysis and preliminary testing of the prototype 201 MHz copper cavity for a muon ionization cooling channel. Cavity applications include the Muon Ionization Cooling Experiment (MICE) as well as cooling channels for a neutrino factory or a muon collider. This cavity was developed by the US muon cooling (MUCOOL) collaboration and is being tested in the MUCOOL Test Area (MTA) at Fermilab. To achieve a high accelerating gradient, the cavity beam irises are terminated by a pair of curved, thin beryllium windows. Several fabrication methods developed for the cavity and windows are novel and offer significant cost savings as compared to conventional construction methods. The cavity's thermal and structural performances are simulated with an FEA model. Preliminary high power RF commissioning results will be presented

  9. Driven-Dissipative Supersolid in a Ring Cavity

    Science.gov (United States)

    Mivehvar, Farokh; Ostermann, Stefan; Piazza, Francesco; Ritsch, Helmut

    2018-03-01

    Supersolids are characterized by the counterintuitive coexistence of superfluid and crystalline order. Here we study a supersolid phase emerging in the steady state of a driven-dissipative system. We consider a transversely pumped Bose-Einstein condensate trapped along the axis of a ring cavity and coherently coupled to a pair of degenerate counterpropagating cavity modes. Above a threshold pump strength the interference of photons scattered into the two cavity modes results in an emergent superradiant lattice, which spontaneously breaks the continuous translational symmetry towards a periodic atomic pattern. The crystalline steady state inherits the superfluidity of the Bose-Einstein condensate, thus exhibiting genuine properties of a supersolid. A gapless collective Goldstone mode correspondingly appears in the superradiant phase, which can be nondestructively monitored via the relative phase of the two cavity modes on the cavity output. Despite cavity-photon losses the Goldstone mode remains undamped, indicating the robustness of the supersolid phase.

  10. Cavity Quantum Electrodynamics of Continuously Monitored Bose-Condensed Atoms

    Directory of Open Access Journals (Sweden)

    Mark D. Lee

    2015-09-01

    Full Text Available We study cavity quantum electrodynamics of Bose-condensed atoms that are subjected to continuous monitoring of the light leaking out of the cavity. Due to a given detection record of each stochastic realization, individual runs spontaneously break the symmetry of the spatial profile of the atom cloud and this symmetry can be restored by considering ensemble averages over many realizations. We show that the cavity optomechanical excitations of the condensate can be engineered to target specific collective modes. This is achieved by exploiting the spatial structure and symmetries of the collective modes and light fields. The cavity fields can be utilized both for strong driving of the collective modes and for their measurement. In the weak excitation limit the condensate–cavity system may be employed as a sensitive phonon detector which operates by counting photons outside the cavity that have been selectively scattered by desired phonons.

  11. M10.3.1: LHC crab cavity specifications completed

    CERN Document Server

    Ciapala, E

    2010-01-01

    • The starting point of Sub-task 1 is to determine the full LHC system requirements for the crab cavity system. This milestone concerns completion of basic specifications for the crab cavity system. This comprises the beam requirements, the cavity impedance constraints, the operating conditions and constraints, the layout and integration constraints in LHC and very importantly machine protection issues. The specifications of the cavity itself and its ancillaries follow from these system requirements and on the technology chosen for the cavity design. • The beam requirements result from the known parameters of the LHC upgrade lattice and the expected LHC beam parameters at ultimate bunch intensity. There are boundary conditions imposed by certain beam parameters such as the bunch length and intensity and by the machine layout, mainly the available beam pipe separations at the proposed cavity positions. Requirements on RF noise and stability are tight, to avoid emittance blow-up. Machine protection issues a...

  12. LHC crab cavity specifications milestone: M10.3.1

    CERN Document Server

    Calaga, R; Jensen, E; McIntosh, P; Shaposhnikova, E; Tuckmantel, J; Zimmermann, F

    2010-01-01

    The starting point of Sub-task 1 is to determine the full LHC system requirements for the crab cavity system. This milestone concerns completion of basic specifications for the crab cavity system. This comprises the beam requirements, the cavity impedance constraints, the operating conditions and constraints, the layout and integration constraints in LHC and very importantly machine protection issues. The specifications of the cavity itself and its ancillaries follow from these system requirements and on the technology chosen for the cavity design. The beam requirements result from the known parameters of the LHC upgrade lattice and the expected LHC beam parameters at ultimate bunch intensity. There are boundary conditions imposed by certain beam parameters such as the bunch length and intensity and by the machine layout, mainly the available beam pipe separations at the proposed cavity positions. Requirements on RF noise and stability are tight, to avoid emittance blow-up. Machine protection issues arise fro...

  13. A database for superconducting cavities for the TESLA Test Facility

    International Nuclear Information System (INIS)

    Gall, P.D.; Goessel, A.; Gubarev, V.; Iversen, J.

    2006-01-01

    We look back on 10 years experience using a database for superconducting cavities for the TESLA Test Facility (TTF). The database was developed to collect data of every preparation step and measurement in order to optimize cavity production and preparation techniques to meet the ambitious goal of high accelerating gradients at high quality factors. Data from 110 superconducting 9-cell cavities, 50 single cell cavities, several 2- to 7-cell cavities and about 60 RF couplers were collected in the database. In addition, company measurements on sub-assemblies and parts forming the next 30 9-cell cavities were stored, thus establishing the database as part of a quality management system. This database is dynamically accessible via an extensive graphical web-interface based on ORACLE products, which enables the users to select and analyse the collected data easily from anywhere

  14. Central solar-energy receiver

    Science.gov (United States)

    Not Available

    1981-10-27

    An improved tower-mounted central solar energy receiver for heating air drawn through the receiver by an induced draft fan is described. A number of vertically oriented, energy absorbing, fin-shaped slats are radially arranged in a number of concentric cylindrical arrays on top of the tower coaxially surrounding a pipe having air holes through which the fan draws air which is heated by the slats which receive the solar radiation from a heliostat field. A number of vertically oriented and wedge-shaped columns are radially arranged in a number of concentric cylindrical clusters surrounding the slat arrays. The columns have two mirror-reflecting sides to reflect radiation into the slat arrays and one energy absorbing side to reduce reradiation and reflection from the slat arrays.

  15. Design and calibration of the 34 GHz Yale microwave cavity experiment

    Energy Technology Data Exchange (ETDEWEB)

    Slocum, P.L., E-mail: penny.slocum@yale.edu [Department of Physics, Yale University, PO Box 208120, New Haven, CT 06520 (United States); Baker, O.K. [Department of Physics, Yale University, PO Box 208120, New Haven, CT 06520 (United States); Hirshfield, J.L. [Department of Physics, Yale University, PO Box 208120, New Haven, CT 06520 (United States); Omega-P, Inc., 291 Whitney Ave., Suite 401, New Haven, CT 06511 (United States); Jiang, Y.; Malagon, A.T.; Martin, A.J.; Shchelkunov, S. [Department of Physics, Yale University, PO Box 208120, New Haven, CT 06520 (United States); Szymkowiak, A. [Department of Physics, Yale University, PO Box 208120, New Haven, CT 06520 (United States); Department of Astronomy, Yale University, PO Box 208101, New Haven, CT 06520 (United States)

    2015-01-11

    Several proposed models of the cold dark matter in the universe include light neutral bosons with sub-eV masses. In many cases their detection hinges on their infrequent interactions with Standard Model photons at sub-eV energies. We describe the design and performance of an experiment to search for aberrations from the broadband noise power associated with a 5 K copper resonant cavity in the vicinity of 34 GHz (0.1 meV). The cavity, microwave receiver, and data reduction are described. Several configurations of the experiment are discussed in terms of their impact on the sensitivity of the search for axion-like particles and hidden sector photons.

  16. First Test Results of the 4-ROD Crab Cavity

    CERN Document Server

    Ambattu, P; Burt, G; Calaga, R; Capatina, O; Calatroni, S; Ciapala, E; Doherty, D; Ferreira, L; Jensen, E; Hall, B; Lingwood, C; Maesen, P; Mongelluzzo, A; Renaglia, T; Therasse, M

    2013-01-01

    The first compact prototype crab cavity with the 4rod geometry has undergone surface treatment and cold testing. Due to the complex geometry and unique fabrication procedure, RF validation of the field at beyond the nominal operating voltage at a sufficiently high Q0 is an important pre-requisite. Preliminary results of the first cold tests are presented along with cavity performance at different stages of the cavity processing is described.

  17. Cavity enhanced immunoassay measurements in microtiter plates using BBCEAS

    OpenAIRE

    Bajuszova, Z; Ali, Z; Scott, SM; Seetohul, LN; Islam, M

    2016-01-01

    We report on the first detailed use of broadband cavity enhanced absorption spectroscopy (BBCEAS) as a detection system for immunoassay. A vertical R ≥ 0.99 optical cavity was integrated with a motorised XY stage, which functioned as a receptacle for 96 well microtiter plates. The custom built cavity enhanced microplate reader was used to make measurements on a commercially available osteocalcin sandwich ELISA kit. A 30 fold increase in path length was obtained with a minimum detectable chang...

  18. Ultimate Gradient Limitation in Niobium Superconducting Accelerating Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Checchin, Mattia [Illinois Inst. of Technology, Chicago, IL (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Grassellino, Anna [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Martinello, Martina [Illinois Inst. of Technology, Chicago, IL (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Posen, Sam [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Romanenko, Alexander [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Zasadzinski, John [Illinois Inst. of Technology, Chicago, IL (United States)

    2016-06-01

    The present study is addressed to the theoretical description of the ultimate gradient limitation in SRF cavities. Our intent is to exploit experimental data to confirm models which provide feed-backs on how to improve the current state-of-art. New theoretical insight on the cavities limiting factor can be suitable to improve the quench field of N-doped cavities, and therefore to take advantage of high Q0 at high gradients.

  19. Prototype 350 MHz niobium spoke-loaded cavities

    International Nuclear Information System (INIS)

    Delayen, J. R.; Kedzie, M.; Mammosser, J.; Piller, C.; Shepard, K. W.

    1999-01-01

    This paper reports the development of 350 MHz superconducting cavities of a spoke-loaded geometry, intended for the velocity range 0.2 < v/c < 0.6. Two prototype single-cell cavities have been designed, one optimized for velocity v/c = 0.4, and the other for v/c = 0.29. Construction of the prototype niobium cavities is nearly complete. Details of the design and construction are discussed, along with the results of cold tests

  20. Prototype 350 MHz niobium spoke-loaded cavities.

    Energy Technology Data Exchange (ETDEWEB)

    Delayen, J. R.; Kedzie, M.; Mammosser, J.; Piller, C.; Shepard, K. W.

    1999-05-10

    This paper reports the development of 350 MHz superconducting cavities of a spoke-loaded geometry, intended for the velocity range 0.2 < v/c < 0.6. Two prototype single-cell cavities have been designed, one optimized for velocity v/c = 0.4, and the other for v/c = 0.29. Construction of the prototype niobium cavities is nearly complete. Details of the design and construction are discussed, along with the results of cold tests.

  1. Hydrodynamic modeling of semi-planing hulls with air cavities

    Directory of Open Access Journals (Sweden)

    Konstantin I. Matveev

    2015-05-01

    Full Text Available High-speed heavy loaded monohull ships can benefit from application of drag-reducing air cavities under stepped hull bottoms. The subject of this paper is the steady hydrodynamic modeling of semi-planing air-cavity hulls. The current method is based on a linearized potential-flow theory for surface flows. The mathematical model description and parametric calculation results for a selected configuration with pressurized and open air cavities are presented.

  2. Trains of electron pulses generation using multi-stage cavities

    International Nuclear Information System (INIS)

    Kamada, Masaki; Mori, Michiya; Sugawara, Kazuyoshi; Yamada, Yoko; Kurihara, Kazuteru; Shirasaka, Haruki; Nishiguchi, Takashi; Ando, Ritoku; Kamada, Keiichi

    2002-01-01

    Automodulation of an intense relativistic electron beam was reexamined experimentally to obtain trains of subnanosecond electron bunches. Sufficient beam modulation with frequency larger than 1 GHz was expected for the trains of subnanosecond bunches. It was obtained when a short pulse electron beam with energy of 550 keV, current of 4 kA, pulse duration of 12 ns and current rise time of 2ns was injected to a series of four coaxial cavities with the length of 75 mm. However, only a poor modulation was observed when a long pulse electron beam of 700 keV, 4 kA, 175 ns with current rise time of 20 ns was injected to the same cavities. Transmission line theory as well PIC code simulation suggested that the round trip time for the electromagnetic wave in the cavity must be longer than the rise time of the beam current to obtain the high level current modulation. Therefore, we studied experimentally how the ratio between the beam current rise time and the length of the cavity affects on the level of current modulation. Single cavity experiments were carried out with the short pulse beam. Single cavity with the length of 75, 150 or 300 mm was utilized. The round trip times for 75 and 150 mm cavities are shorter than the current rise time of 2 ns. The experiments with a 75 or 150 mm cavity resulted in suppression of the modulation amplitude. In the case of a 300 mm cavity, the high level modulation was obtained. The simulation results showed good agreements with the experimental results. We employed a series of cavities with decreasing lengths to improve the current rise time. For the short pulse beam, the high level current 1 GHz modulation was obtained when two 75 mm cavities were set at the downstream side of cavities with lengths of 300 mm and 150 mm. (author)

  3. Nanohybrid composite vs. fine hybrid composite in extended class II cavities: clinical and microscopic results after 2 years.

    Science.gov (United States)

    Krämer, Norbert; Reinelt, Christian; García-Godoy, Franklin; Taschner, Michael; Petschelt, Anselm; Frankenberger, Roland

    2009-08-01

    To evaluate the clinical behavior of two different resin composites in Class II cavities over a period of 2 years in a controlled prospective split-mouth study. 30 subjects received 68 direct resin composite restorations (Grandio bonded with Solobond M: n=36, Tetric Ceram bonded with Syntac: n=32) by one dentist in a private practice. All restorations were replacement restorations, 24 cavities (35%) revealed no enamel at the bottom of the proximal box, in 33 cavities (48%) the proximal enamel width was 0.05; Mann-Whitney U-test). A significant deterioration was found over time for marginal integrity, tooth integrity, restoration integrity and proximal contact (P < 0.05; Friedman test). SLM and SEM analysis of restoration margins only revealed differences in the amount of detectable perfect margins, in favor of Tetric Ceram (P < 0.05). Both materials performed satisfactorily over the 2-year observation period.

  4. Superconducting spoke cavities for high-velocity applications

    Energy Technology Data Exchange (ETDEWEB)

    Hopper, Christopher S. [Old Dominion U.; Delayen, Jean R. [Old Dominion U., JLAB

    2013-10-01

    To date, superconducting spoke cavities have been designed, developed, and tested for particle velocities up to {beta}{sub 0}~0.6, but there is a growing interest in possible applications of multispoke cavities for high-velocity applications. We have explored the design parameter space for low-frequency, high-velocity, double-spoke superconducting cavities in order to determine how each design parameter affects the electromagnetic properties, in particular the surface electromagnetic fields and the shunt impedance. We present detailed design for cavities operating at 325 and 352 MHz and optimized for {beta}{sub 0}~=0.82 and 1.

  5. Physical simulations of cavity closure in a creeping material

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, H.J.; Preece, D.S.

    1985-09-01

    The finite element method has been used extensively to predict the creep closure of underground petroleum storage cavities in rock salt. Even though the numerical modeling requires many simplifying assumptions, the predictions have generally correlated with field data from instrumented wellheads, however, the field data are rather limited. To gain an insight into the behavior of three-dimensional arrays of cavities and to obtain a larger data base for the verification of analytical simulations of creep closure, a series of six centrifuge simulation experiments were performed using a cylindrical block of modeling clay, a creeping material. Three of the simulations were conducted with single, centerline cavities, and three were conducted with a symmetric array of three cavities surrounding a central cavity. The models were subjected to body force loading using a centrifuge. For the single cavity experiments, the models were tested at accelerations of 100, 125 and 150 g's for 2 hours. For the multi-cavity experiments, the simulations were conducted at 100 g's for 3.25 hours. The results are analyzed using dimensional analyses. The analyses illustrate that the centrifuge simulations yield self-consistent simulations of the creep closure of fluid-filled cavities and that the interaction of three-dimensional cavity layouts can be investigated using this technique.

  6. Accelerator cavities as a probe of millicharged particles

    Energy Technology Data Exchange (ETDEWEB)

    Gies, H. [Heidelberg Univ. (Germany). Inst. fuer Theoretische Physik; Jaeckel, J.; Ringwald, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2006-08-15

    We investigate Schwinger pair production of millicharged fermions in the strong electric field of cavities used for particle accelerators. Even without a direct detection mechanism at hand, millicharged particles, if they exist, contribute to the energy loss of the cavity and thus leave an imprint on the cavity's quality factor. Already conservative estimates substantially constrain the electric charge of these hypothetical particles; the resulting bounds are competitive with the currently best laboratory bounds which arise from experiments based on polarized laser light propagating in a magnetic field. We propose an experimental setup for measuring the electric current comprised of the millicharged particles produced in the cavity. (orig.)

  7. Thermal and dynamic effects in electron beam welding cavities

    Energy Technology Data Exchange (ETDEWEB)

    Schauer, D.A.

    1977-08-01

    An experimental and analytical study of the temperature distributions along the molten metal surface in an electron beam welding cavity is described. Surface temperature distributions in cavities were measured with a narrow band infrared radiation pyrometer. The availability of the cavity temperature measurements allowed estimates to be made for the vapor pressure and surface energy forces as a function of cavity position. The results indicated a force imbalance occurred in the cavity. It is postulated that at the location of the force imbalance a liquid material projection forms periodically and moves into the path of the electron beam. The liquid in this projection is driven towards the bottom, partially filling the cavity. This action is followed by the electron beam pushing the liquid aside to form a maximum depth cavity. This process is then repeated. An analysis for predicting cavity oscillation frequency shows reasonable agreement with frequencies measured at the weld root determined from weld sections. A study of the measured temperature distributions in cavities of varying depth combined with the force imbalance observations led to an interpretation of when spiking might occur. A procedure is proposed for determining the spiking tendency for a given set of weld parameters. The results of this study permit a designer to select apriori the best set of weld parameters to achieve a weld of predictable quality.

  8. Thermal and dynamic effects in electron beam welding cavities

    International Nuclear Information System (INIS)

    Schauer, D.A.

    1977-08-01

    An experimental and analytical study of the temperature distributions along the molten metal surface in an electron beam welding cavity is described. Surface temperature distributions in cavities were measured with a narrow band infrared radiation pyrometer. The availability of the cavity temperature measurements allowed estimates to be made for the vapor pressure and surface energy forces as a function of cavity position. The results indicated a force imbalance occurred in the cavity. It is postulated that at the location of the force imbalance a liquid material projection forms periodically and moves into the path of the electron beam. The liquid in this projection is driven towards the bottom, partially filling the cavity. This action is followed by the electron beam pushing the liquid aside to form a maximum depth cavity. This process is then repeated. An analysis for predicting cavity oscillation frequency shows reasonable agreement with frequencies measured at the weld root determined from weld sections. A study of the measured temperature distributions in cavities of varying depth combined with the force imbalance observations led to an interpretation of when spiking might occur. A procedure is proposed for determining the spiking tendency for a given set of weld parameters. The results of this study permit a designer to select apriori the best set of weld parameters to achieve a weld of predictable quality

  9. Improved surface treatment of the superconducting TESLA cavities

    CERN Document Server

    Lilje, L; Benvenuti, Cristoforo; Bloess, D; Charrier, J P; Chiaveri, Enrico; Ferreira, L; Losito, R; Matheisen, A; Preis, H; Proch, D; Reschke, D; Safa, H; Schmüser, P; Trines, D; Visentin, B; Wenninger, Horst

    2004-01-01

    The proposed linear electron-positron collider TESLA is based on 1.3 GHz superconducting niobium cavities for particle acceleration. For a centre-of-mass energy of 500 GeV, an accelerating field of 23.4 MV/m is required which is reliably achieved with a niobium surface preparation by chemical etching. An upgrade of the collider to 800 GeV requires an improved cavity preparation technique. In this paper, results are presented on single-cell cavities which demonstrate that fields of up to 40 MV/m are accessible by electrolytic polishing of the inner surface of the cavity.

  10. Experimental analysis of surface finish in normal conducting cavities

    Science.gov (United States)

    Zarrebini-Esfahani, A.; Aslaninejad, M.; Ristic, M.; Long, K.

    2017-10-01

    A normal conducting 805 MHz test cavity with an in built button shaped sample is used to conduct a series of surface treatment experiments. The button enhances the local fields and influences the likelihood of an RF breakdown event. Because of their smaller sizes, compared to the whole cavity surface, they allow practical investigations of the effects of cavity surface preparation in relation to RF breakdown. Manufacturing techniques and steps for preparing the buttons to improve the surface quality are described in detail. It was observed that even after the final stage of the surface treatment, defects on the surface of the cavities still could be found.

  11. Investigation on computation of elliptical microwave plasma cavity

    Science.gov (United States)

    Liao, Xiaoli; Liu, Hua; Zhang, Kai

    2008-12-01

    In recent years, the advance of the elliptical resonant cavity and focus cavity is known by many people. There are homogeneous and multipatternal virtues in the focus dimensional microwave field of the elliptical resonant cavity. It is very suitable for applying the low power microwave biological effect equipment. However, when designing the elliptical resonant cavity may meet the problems of complex and huge computation need to be solved. This paper proposed the simple way of approximate processing the Mathieu function. It can greatly simplify the difficulty and decrease the scale of computation. This method can satisfy the requirements of research and development within project permitted precision.

  12. Fabrication process for the PEP II RF cavities

    Energy Technology Data Exchange (ETDEWEB)

    Franks, R.M.; Rimmer, R.A. [Lawrence Berkeley National Lab., CA (United States); Schwarz, H. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1997-06-05

    This paper presents the major steps used in the fabrication of the 26 RF Cavities required for the PEP-II B-factory. Several unique applications of conventional processes have been developed and successfully implemented: electron beam welding (EBW), with minimal porosity, of .75 inch (19 mm) copper cross-sections; extensive 5-axis milling of water channels; electroplating of .37 inch (10 mm) thick OFE copper; tuning of the cavity by profiling beam noses prior to final joining with the cavity body; and machining of the cavity interior, are described here.

  13. Multipactor in crossed rf fields on the cavity equator

    Directory of Open Access Journals (Sweden)

    Valery Shemelin

    2013-01-01

    Full Text Available Multipactor discharge in an accelerating superconducting elliptic cavity occurs usually near its equator. As simulations show, the dimensions of the trajectories of multipacting electrons are very small compared to the dimensions of a cavity. This feature gives a way for solving explicit equations of motion instead of cumbersome simulations. Electric and magnetic fields near the cavity equator are presented in a form of expansions up to the third power of coordinates. Comparisons with numerical calculations of fields made with the SLANS code for the TESLA cavity cells, as well as with the analytical solution for a spherical cavity, are done. These fields are used for solving the equations of motion of electrons in crossed rf fields near the equator. Based on the analysis of these equations, general features of multipacting in this area are obtained. Results are compared with simulations and experimental data. The experimental formulas for multipacting zones are explained and their dependence on the cavity geometries is shown. Because of small sizes of electron trajectories, the influence of the weld seams is taken into account. This suggests a possible explanation of multipacting in a cavity which was not found by simulations. The developed approach allows evaluation of multipacting in a cavity without its simulations but after an analysis of fields in the equatorial region. These fields can be computed by any code used for cavity calculation.

  14. Internalization of Calcium Oxalate Calculi Developed in Narrow Cavities

    Directory of Open Access Journals (Sweden)

    Fèlix Grases

    2014-03-01

    Full Text Available We describe the case of a patient with calcium oxalate monohydrate and calcium oxalate dihydrate calculi occluded in cavities. All those calculi were located inside narrow cavities covered with a thin epithelium that permits their visualization. Urinary biochemical analysis showed high calciuria, not hypercalciuria, hypocitraturia, and a ratio [calcium]/[citrate] >0.33. The existence of cavities of very low urodynamic efficacy was decisive in the formation of such calculi. It is important to emphasize that we observed a thin epithelium covering such cavities, demonstrating that this epithelium may be formed after the development of the calculi through a re-epithelialization process.

  15. Cavity characterization for general use in linear electron accelerators

    International Nuclear Information System (INIS)

    Souza Neto, M.V. de.

    1985-01-01

    The main objective of this work is to is to develop measurement techniques for the characterization of microwave cavities used in linear electron accelerators. Methods are developed for the measurement of parameters that are essential to the design of an accelerator structure using conventional techniques of resonant cavities at low power. Disk-loaded cavities were designed and built, similar to those in most existing linear electron accelerators. As a result, the methods developed and the estimated accuracy were compared with those from other investigators. The results of this work are relevant for the design of cavities with the objective of developing linear electron accelerators. (author) [pt

  16. A novel nano-sensor based on optomechanical crystal cavity

    Science.gov (United States)

    Zhang, Yeping; Ai, Jie; Ma, Jingfang

    2017-10-01

    Optical devices based on new sensing principle are widely used in biochemical and medical area. Nowadays, mass sensing based on monitoring the frequency shifts induced by added mass in oscillators is a well-known and widely used technique. It is interesting to note that for nanoscience and nanotechnology applications there is a strong demand for very sensitive mass sensors, being the target a sensor for single molecule detection. The desired mass resolution for very few or even single molecule detection, has to be below the femtogram range. Considering the strong interaction between high co-localized optical mode and mechanical mode in optomechanical crystal (OMC) cavities, we investigate OMC splitnanobeam cavities in silicon operating near at the 1550nm to achieve high optomechanical coupling rate and ultra-small motion mass. Theoretical investigations of the optical and mechanical characteristic for the proposed cavity are carried out. By adjusting the structural parameters, the cavity's effective motion mass below 10fg and mechanical frequency exceed 10GHz. The transmission spectrum of the cavity is sensitive to the sample which located on the center of the cavity. We conducted the fabrication and the characterization of this cavity sensor on the silicon-on-insulator (SOI) chip. By using vertical coupling between the tapered fiber and the SOI chip, we measured the transmission spectrum of the cavity, and verify this cavity is promising for ultimate precision mass sensing and detection.

  17. Nylon Sleeve for Cavity Amplifier Holds Tuning Despite Heat

    Science.gov (United States)

    Derr, Lloyd

    1964-01-01

    The problem: Detuning of cavity amplifiers with change in temperature. This results in deterioration of the performance of the amplifier at its design frequency. In cavity amplifiers and filters it is desirable that constant performance be maintained regardless of thermal changes. These changes often cause an "off resonance shift" in a cavity filter and a deterioration of performance in a cavity amplifier. The solution: Mount the tuning probe in a nylon sleeve. Thermal expansion and contraction of the nylon nullifies unwanted capacitive and inductive changes in the resonant elements.

  18. Cerebellar cortical infarct cavities and vertebral artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Cocker, Laurens J.L. de [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Kliniek Sint-Jan Radiologie, Brussels (Belgium); Compter, A.; Kappelle, L.J.; Worp, H.B. van der [University Medical Center Utrecht, Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, Utrecht (Netherlands); Luijten, P.R.; Hendrikse, J. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands)

    2016-09-15

    Cerebellar cortical infarct cavities are a newly recognised entity associated with atherothromboembolic cerebrovascular disease and worse physical functioning. We aimed to investigate the relationship of cerebellar cortical infarct cavities with symptomatic vertebrobasilar ischaemia and with vascular risk factors. We evaluated the MR images of 46 patients with a recent vertebrobasilar TIA or stroke and a symptomatic vertebral artery stenosis ≥50 % from the Vertebral Artery Stenting Trial (VAST) for the presence of cerebellar cortical infarct cavities ≤1.5 cm. At inclusion in VAST, data were obtained on age, sex, history of vertebrobasilar TIA or stroke, and vascular risk factors. Adjusted risk ratios were calculated with Poisson regression analyses for the relation between cerebellar cortical infarct cavities and vascular risk factors. Sixteen out of 46 (35 %) patients showed cerebellar cortical infarct cavities on the initial MRI, and only one of these 16 patients was known with a previous vertebrobasilar TIA or stroke. In patients with symptomatic vertebrobasilar ischaemia, risk factor profiles of patients with cerebellar cortical infarct cavities were not different from patients without these cavities. Cerebellar cortical infarct cavities are seen on MRI in as much as one third of patients with recently symptomatic vertebral artery stenosis. Since patients usually have no prior history of vertebrobasilar TIA or stroke, cerebellar cortical infarct cavities should be added to the spectrum of common incidental brain infarcts visible on routine MRI. (orig.)

  19. Ring cavity for a Raman capillary waveguide amplifier

    Science.gov (United States)

    Kurnit, N.A.

    1981-01-27

    A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

  20. Ring cavity for a Raman capillary waveguide amplifir

    Science.gov (United States)

    Kurnit, N.A.

    1981-01-27

    A regenerative ring amplifier and regenerative ring oscillator are described which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO/sub 2/ laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplified Stokes signal is synchronous with the mode-locked spikes of the incoming CO/sub 2/ laser pump signal.

  1. Tunable cavity resonator including a plurality of MEMS beams

    Science.gov (United States)

    Peroulis, Dimitrios; Fruehling, Adam; Small, Joshua Azariah; Liu, Xiaoguang; Irshad, Wasim; Arif, Muhammad Shoaib

    2015-10-20

    A tunable cavity resonator includes a substrate, a cap structure, and a tuning assembly. The cap structure extends from the substrate, and at least one of the substrate and the cap structure defines a resonator cavity. The tuning assembly is positioned at least partially within the resonator cavity. The tuning assembly includes a plurality of fixed-fixed MEMS beams configured for controllable movement relative to the substrate between an activated position and a deactivated position in order to tune a resonant frequency of the tunable cavity resonator.

  2. HOM frequency control of SRF cavity in high current ERLs

    Science.gov (United States)

    Xu, Chen; Ben-Zvi, Ilan

    2018-03-01

    The acceleration of high-current beam in Superconducting Radio Frequency (SRF) cavities is a challenging but essential for a variety of advanced accelerators. SRF cavities should be carefully designed to minimize the High Order Modes (HOM) power generated in the cavities by the beam current. The reduction of HOM power we demonstrate in a particular case can be quite large. This paper presents a method to systematically control the HOM resonance frequencies in the initial design phase to minimize the HOM power generation. This method is expected to be beneficial for the design of high SRF cavities addressing a variety of Energy Recovery Linac (ERL) applications.

  3. Demonstration of an optical enhancement cavity with 10 micron wavelength

    Science.gov (United States)

    Sakaue, K.; Washio, M.; Endo, A.

    2015-05-01

    We have been developing a pulsed-laser optical enhancement cavity for laser-Compton scattering (LCS). LCS can produce high brightness X-ray through the collision between relativistic electrons generated from the accelerator and high power laser photons with a compact facility. In order to increase the number of collisions/sec, high repetition rate accelerator and laser are required. For the laser system, an optical enhancement cavity is the most powerful tool for LCS, thus we have been developing the cavity for storing 1 micron laser pulse. On the other hand, the resulting X-ray energy can be changed by the collision laser wavelength. If we have another optical cavity with different wavelength, the multicolor, quasi-monochromatic, high brightness and compact X-ray source can be realized. Therefore, we started to develop an optical cavity at 10 micron wavelength with CO2 laser. At this wavelength region, the absorption loss is dominant compared with scattering loss. Thus we carefully chose the optical mirrors for enhancement cavity. We demonstrated a more than 200 enhancement factor with 795 finesse optical cavity at 10 micron CO2 laser. Moreover, 2.3 kW storage in the optical cavity was successfully demonstrated. The design of optical cavity, first experimental results and future prospects will be presented at the conference.

  4. Perfect routing of quantum information in regular cavity QED networks

    Science.gov (United States)

    Behzadi, Naghi; Rudsary, Sobhan Kazemi; Salmasi, Bahram Ahansaz

    2013-12-01

    We introduce a scheme for perfect routing of quantum states and entanglement in regular cavity QED networks. The couplings between the cavities are quasi-uniform and each cavity is doped with a two-level atom. Quasi-uniform couplings leads the system to evolve in invariant subspaces. Combination the evolutions of the system in its invariant subspaces with quite simple local operations on atoms in the networks, gives the perfect routing of quantum states and entanglement through the network. To provide the protocol be robust due to decoherence arisen from photon loss, the field mode of the cavities are only virtually excited.

  5. Rf drive system for the CEBAF superconducting cavities

    International Nuclear Information System (INIS)

    Fugitt, J.A.; Moore, T.L.

    1986-01-01

    To obtain the maximum accelerating gradient, the CEBAF RF system uses an individually controlled RF drive chain for each superconducting cavity. This allows one to adjust each cavity to its individual maximum field. Due to material purity and manufacturing tolerances of the cavities, it is expected that this maximum value will be distributed over an almost 2 to 1 gradient range. The requirement for precise individual phase and gradient control of 420 superconducting accelerating cavities, is accomplished through the use of individual fault tolerant RF drive chains and self monitoring control electronics. This might be thought of as the Phased Array approach to accelerator RF systems

  6. Books Received Information and Announcements ...

    Indian Academy of Sciences (India)

    Books Received. Tradition, Science and Society. 5 Balachandra Roo. Navakarnataka. 1990, Rs.1S. A Textbook of Biology - Volume 2. P KG Nair, K P Achor, M J Hegde and 5 G Prabhu. Himalaya Publishing House. 1996, Rs.1S0. Indus Script - Its Nature and Structure. B V SUbbarayappa. New Era Publications. 1996 ...

  7. Advances in SIS receiver technology

    Science.gov (United States)

    Frerking, M. A.

    1988-01-01

    Significant advances in SIS receiver technology since the last Asilomar meeting include: superconductor materials, integrated inductive tuning elements, and planar mounting structures. The effect of these advances is to push the upper frequency operating limit from about 600 to 1500 GHz, and to enhance the feasibility of focal plane arrays of heterodyne receivers. A fundamental high frequency operating limit of SIS mixers is set by the superconducting energy gap. A practical limitation for high frequency operation of SIS junctions is their parasitic capacitance and resistance. The performance of the mixer will be degraded by the Resistor-Capacitor rolloff. Several designs were reported for inductive elements integrated on the same substrate as the SIS junctions to tune out the bulk junction capacitance. Most millimeter SIS-based heterodyne receivers have used waveguide coupling structures. Technology has advanced to the state where programs that have a high probability of success can be defined to produce arrays of SIS receivers for frequencies as high as 1500 GHz.

  8. Madhu Sudan Receives Nevanlinna Prize

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 12. Madhu Sudan Receives Nevanlinna Prize. Meena Mahajan Priti Shankar ... Author Affiliations. Meena Mahajan1 Priti Shankar1. Department of Computer Science and Automation, Indian Institute of Science, Bangaiore 560 012, India.

  9. Partitioning of a DRM receiver

    NARCIS (Netherlands)

    Wolkotte, P.T.; Smit, Gerardus Johannes Maria; Smit, L.T.

    In this article we present the results of partitioning the OFDM baseband processing of a DRM receiver into smaller independent processes. Furthermore, we give a short introduction into the relevant parts of the DRM standard. Based on the number of multiplications and additions we can map individual

  10. A pulsated weak-resonant-cavity laser diode with transient wavelength scanning and tracking for injection-locked RZ transmission.

    Science.gov (United States)

    Lin, Gong-Ru; Chi, Yu-Chieh; Liao, Yu-Sheng; Kuo, Hao-Chung; Liao, Zhi-Wang; Wang, Hai-Lin; Lin, Gong-Cheng

    2012-06-18

    By spectrally slicing a single longitudinal-mode from a master weak-resonant-cavity Fabry-Perot laser diode with transient wavelength scanning and tracking functions, the broadened self-injection-locking of a slave weak-resonant-cavity Fabry-Perot laser diode is demonstrated to achieve bi-directional transmission in a 200-GHz array-waveguide-grating channelized dense-wavelength-division-multiplexing passive optical network system. Both the down- and up-stream slave weak-resonant-cavity Fabry-Perot laser diodes are non-return-to-zero modulated below threshold and coherently injection-locked to deliver the pulsed carrier for 25-km bi-directional 2.5 Gbits/s return-to-zero transmission. The master weak-resonant-cavity Fabry-Perot laser diode is gain-switched at near threshold condition and delivers an optical coherent pulse-train with its mode linewidth broadened from 0.2 to 0.8 nm by transient wavelength scanning, which facilitates the broadband injection-locking of the slave weak-resonant-cavity Fabry-Perot laser diodes with a threshold current reducing by 10 mA. Such a transient wavelength scanning induced spectral broadening greatly releases the limitation on wavelength injection-locking range required for the slave weak-resonant-cavity Fabry-Perot laser diode. The theoretical modeling and numerical simulation on the wavelength scanning and tracking effects of the master and slave weak-resonant-cavity Fabry-Perot laser diodes are performed. The receiving power sensitivity for back-to-back transmission at bit-error-rate transmission is less than 2 dB for all 16 channels.

  11. Solar central receiver reformer system for ammonia plants

    Science.gov (United States)

    1980-07-01

    Details of the conceptual design, economic analysis, and development plan for a solar central receiver system for retrofitting the Valley Nitrogen Producers, Inc., El Centro, California 600 ST/SD Ammonia Plant are presented. The retrofit system consists of a solar central receiver reformer (SCRR) operating in parallel with the existing fossil fired reformer. Steam and hydrocarbon react in the catalyst filled tubes of the inner cavity receiver to form a hydrogen rich mixture which is the syngas feed for the ammonia production. The SCRR system displaces natural gas presently used in the fossil reformer combustion chamber. The solar reformer retrofit system characteristics and its interface with the existing plant are simple, incorporating state of the art components with proven technology. A northfield composed of one thousand forty second generation heliostats provides solar energy to the receiver which is positioned on top of a 90 meter high steel tower. The overall economics of this system can provide over 20% discount cash flow rate of return with proper investment and market conditions.

  12. Is the human nasal cavity at risk from inhaled radionuclides?

    International Nuclear Information System (INIS)

    Boecker, B.B.; Hahn, F.F.; Cuddihy, R.G.; Snipes, M.B.; McClellan, R.O.

    1986-01-01

    In a series of three life-span studies in which beagle dogs inhaled relatively soluble forms of beta-emitting radionuclides, a number of cancers of the nasal cavity have arisen at long times after the inhalation exposure. No such cancers were observed in the control dogs. Data obtained in other studies involving serial sacrifice of dogs that received these radionuclides in similar forms have shown that high local concentrations of the radionuclides can persist in nasal turbinates for long periods of time, depending on the physical half-life of the radionuclide inhaled. Several nasal carcinomas have also been observed in dogs injected with 137 CsCl in which the relative concentrations of beta activity in the turbinate region were not as pronounced as in the above studies. Similar risks of sinonasal cancer were calculated for dogs in each of these studies regardless of differences in radionuclide, dosimetry, and route of administration. Since sinonasal cancers have occurred in people exposed to alpha-emitting radionuclides, it is reasonable to assume this could occur with beta emitters as well. Radiation protection guidelines should account for the sinonasal region being at risk. 23 refs., 1 fig., 6 tabs

  13. Cavity-type hypersonic phononic crystals

    International Nuclear Information System (INIS)

    Sato, A; Fytas, G; Pennec, Y; Djafari-Rouhani, B; Yanagishita, T; Masuda, H; Knoll, W

    2012-01-01

    We report on the engineering of the phonon dispersion diagram in monodomain anodic porous alumina (APA) films through the porosity and physical state of the material residing in the nanopores. Lattice symmetry and inclusion materials are theoretically identified to be the main factors which control the hypersonic acoustic wave propagation. This involves the interaction between the longitudinal and the transverse modes in the effective medium and a flat band characteristic of the material residing in the cavities. Air and filled nanopores, therefore, display markedly different dispersion relations and the inclusion materials lead to a locally resonant structural behavior uniquely determining their properties under confinement. APA films emerge as a new platform to investigate the rich acoustic phenomena of structured composite matter. (paper)

  14. Compact and highly efficient laser pump cavity

    Science.gov (United States)

    Chang, Jim J.; Bass, Isaac L.; Zapata, Luis E.

    1999-01-01

    A new, compact, side-pumped laser pump cavity design which uses non-conventional optics for injection of laser-diode light into a laser pump chamber includes a plurality of elongated light concentration channels. In one embodiment, the light concentration channels are compound parabolic concentrators (CPC) which have very small exit apertures so that light will not escape from the pumping chamber and will be multiply reflected through the laser rod. This new design effectively traps the pump radiation inside the pump chamber that encloses the laser rod. It enables more uniform laser pumping and highly effective recycle of pump radiation, leading to significantly improved laser performance. This new design also effectively widens the acceptable radiation wavelength of the diodes, resulting in a more reliable laser performance with lower cost.

  15. Photon momentum and optical forces in cavities

    DEFF Research Database (Denmark)

    Partanen, Mikko; Häyrynen, Teppo; Oksanen, Jani

    2016-01-01

    During the past century, the electromagnetic field momentum in material media has been under debate in the Abraham-Minkowski controversy as convincing arguments have been advanced in favor of both the Abraham and Minkowski forms of photon momentum. Here we study the photon momentum and optical...... forces in cavity structures in the cases of dynamical and steady-state fields. In the description of the single-photon transmission process, we use a field-kinetic one-photon theory. Our model suggests that in the medium photons couple with the induced atomic dipoles forming polariton quasiparticles...... with the Minkowski form momentum. The Abraham momentum can be associated to the electromagnetic field part of the coupled polariton state. The polariton with the Minkowski momentum is shown to obey the uniform center of mass of energy motion that has previously been interpreted to support only the Abraham momentum...

  16. Long Wave Infrared Cavity Enhanced Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Taubman, Matthew S.; Scott, David C.; Cannon, Bret D.; Myers, Tanya L.; Munley, John T.; Nguyen, Vinh T.; Schultz, John F.

    2005-12-01

    The principal goal of Pacific Northwest National Laboratory's (PNNL's) long wave infrared (LWIR) cavity enhanced sensor (CES) task is to explore ultra-sensitive spectroscopic chemical sensing techniques and apply them to detecting proliferation of weapons of mass destruction (WMD). Our primary application is detecting signatures of WMD production, but LWIR CES techniques are also capable of detecting chemical weapons. The LWIR CES task is concerned exclusively with developing novel point sensors; stand-off detection is addressed by other PNNL tasks and projects. PNNL's LWIR CES research is distinguished from that done by others by the use quantum cascade lasers (QCLs) as the light source. QCLs are novel devices, and a significant fraction of our research has been devoted to developing the procedures and hardware required to implement them most effectively for chemical sensing. This report details the progress we have made on LWIR CES sensor development.

  17. Miniature Cavity-Enhanced Diamond Magnetometer

    Science.gov (United States)

    Chatzidrosos, Georgios; Wickenbrock, Arne; Bougas, Lykourgos; Leefer, Nathan; Wu, Teng; Jensen, Kasper; Dumeige, Yannick; Budker, Dmitry

    2017-10-01

    We present a highly sensitive miniaturized cavity-enhanced room-temperature magnetic-field sensor based on nitrogen-vacancy centers in diamond. The magnetic resonance signal is detected by probing absorption on the 1042-nm spin-singlet transition. To improve the absorptive signal the diamond is placed in an optical resonator. The device has a magnetic-field sensitivity of 28 pT /√{Hz } , a projected photon shot-noise-limited sensitivity of 22 pT /√{Hz } , and an estimated quantum projection-noise-limited sensitivity of 0.43 pT /√{Hz } with the sensing volume of ˜390 μ m ×4500 μ m2 . The presented miniaturized device is the basis for an endoscopic magnetic-field sensor for biomedical applications.

  18. Climate Modeling: Ocean Cavities below Ice Shelves

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Mark Roger [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Computer, Computational, and Statistical Sciences Division

    2016-09-12

    The Accelerated Climate Model for Energy (ACME), a new initiative by the U.S. Department of Energy, includes unstructured-mesh ocean, land-ice, and sea-ice components using the Model for Prediction Across Scales (MPAS) framework. The ability to run coupled high-resolution global simulations efficiently on large, high-performance computers is a priority for ACME. Sub-ice shelf ocean cavities are a significant new capability in ACME, and will be used to better understand how changing ocean temperature and currents influence glacial melting and retreat. These simulations take advantage of the horizontal variable-resolution mesh and adaptive vertical coordinate in MPAS-Ocean, in order to place high resolution below ice shelves and near grounding lines.

  19. Quantum quincunx in cavity quantum electrodynamics

    International Nuclear Information System (INIS)

    Sanders, Barry C.; Bartlett, Stephen D.; Tregenna, Ben; Knight, Peter L.

    2003-01-01

    We introduce the quantum quincunx, which physically demonstrates the quantum walk and is analogous to Galton's quincunx for demonstrating the random walk by employing gravity to draw pellets through pegs on a board, thereby yielding a binomial distribution of final peg locations. In contradistinction to the theoretical studies of quantum walks over orthogonal lattice states, we introduce quantum walks over nonorthogonal lattice states (specifically, coherent states on a circle) to demonstrate that the key features of a quantum walk are observable albeit for strict parameter ranges. A quantum quincunx may be realized with current cavity quantum electrodynamics capabilities, and precise control over decoherence in such experiments allows a remarkable decrease in the position noise, or spread, with increasing decoherence

  20. The splitring loaded RF-cavity

    Science.gov (United States)

    Müller, Eckhard; Klein, Horst

    1984-07-01

    Experimental and theoretical work was done on the splitring loaded resonant rf-cavity. Formulae are derived for the determination of the resonance frequencies, Rp-value and shunt impedance dependent on the resonator geometry. The calculations were verified by experiments carried out by the authors as well as by measurements reported in literature. The theoretical and experimental optimizations were incorporated in a construction of a normal-conducting section laid out for a resonance frequency of 108 MHz, a particle velocity corresponding to β = v/ c = 0.057 and with an Rp-value of 14.5 MΩ producing an acceleration voltage of 1 MV. This resonator is part of a small postaccelerator, installed at the Frankfurt single-ended 7 MV CN Van de Graaff generator and has been tested with a particle beam.

  1. Electronic cigarette explosions involving the oral cavity.

    Science.gov (United States)

    Harrison, Rebecca; Hicklin, David

    2016-11-01

    The use of electronic cigarettes (e-cigarettes) is a rapidly growing trend throughout the United States. E-cigarettes have been linked to the risk of causing explosion and fire. Data are limited on the associated health hazards of e-cigarette use, particularly long-term effects, and available information often presents conflicting conclusions. In addition, an e-cigarette explosion and fire can pose a unique treatment challenge to the dental care provider because the oral cavity may be affected heavily. In this particular case, the patient's injuries included intraoral burns, luxation injuries, and alveolar fractures. This case report aims to help clinicians gain an increased knowledge about e-cigarette design, use, and risks; discuss the risk of spontaneous failure and explosion of e-cigarettes with patients; and understand the treatment challenges posed by an e-cigarette explosion. Copyright © 2016 American Dental Association. Published by Elsevier Inc. All rights reserved.

  2. Air riding seal with purge cavity

    Science.gov (United States)

    Sexton, Thomas D; Mills, Jacob A

    2017-08-15

    An air riding seal for a turbine in a gas turbine engine, where an annular piston is axial moveable within an annular piston chamber formed in a stator of the turbine and forms a seal with a surface on the rotor using pressurized air that forms a cushion in a pocket of the annular piston. A purge cavity is formed on the annular piston and is connected to a purge hole that extends through the annular piston to a lower pressure region around the annular piston or through the rotor to an opposite side. The annular piston is sealed also with inner and outer seals that can be a labyrinth seal to form an additional seal than the cushion of air in the pocket to prevent the face of the air riding seal from overheating.

  3. Cavity Microwave Searches for Cosmological Axions

    CERN Multimedia

    CERN. Geneva

    2005-01-01

    The lecture will cover the searches for dark matter axions based on the microwave cavity experiment of Sikivie. The topics will begin with a brief overview of halo dark matter, and the axion as a candidate. The principle of resonant conversion of axions in an external magnetic field will be described, and practical considerations in optimizing the experiment as a signal-to-noise problem. A major focus of the lecture will be the two complementary strategies for ultra-low noise detection of the microwave photons - the "photon-as-wave" approach (i.e. conventional heterojunction amplifiers and soon quantum-limited SQUID devices), and "photon-as-particle" (i.e. Rydberg-atom single-quantum detection). Experimental results will be presented; these experiments have already reached well into the range of sensitivity to exclude plausible axion models, for limited ranges of mass. The lecture will conclude with a discussion of future plans and challenges for the microwave ca...

  4. Cavity optomechanics in gallium phosphide microdisks

    International Nuclear Information System (INIS)

    Mitchell, Matthew; Barclay, Paul E.; Hryciw, Aaron C.

    2014-01-01

    We demonstrate gallium phosphide (GaP) microdisk optical cavities with intrinsic quality factors >2.8 × 10 5 and mode volumes 3 , and study their nonlinear and optomechanical properties. For optical intensities up to 8.0 × 10 4 intracavity photons, we observe optical loss in the microcavity to decrease with increasing intensity, indicating that saturable absorption sites are present in the GaP material, and that two-photon absorption is not significant. We observe optomechanical coupling between optical modes of the microdisk around 1.5 μm and several mechanical resonances, and measure an optical spring effect consistent with a theoretically predicted optomechanical coupling rate g 0 /2π∼30 kHz for the fundamental mechanical radial breathing mode at 488 MHz

  5. Three-Dimensional Morphology of a Coronal Prominence Cavity

    Science.gov (United States)

    Gibson, S. E.; Kucera, T. A.; Rastawicki, D.; Dove, J.; deToma, G.; Hao, J.; Hill, S.; Hudson, H. S.; Marque, C.; McIntosh, P. S.; hide

    2010-01-01

    We present a three-dimensional density model of coronal prominence cavities, and a morphological fit that has been tightly constrained by a uniquely well-observed cavity. Observations were obtained as part of an International Heliophysical Year campaign by instruments from a variety of space- and ground-based observatories, spanning wavelengths from radio to soft-X-ray to integrated white light. From these data it is clear that the prominence cavity is the limb manifestation of a longitudinally-extended polar-crown filament channel, and that the cavity is a region of low density relative to the surrounding corona. As a first step towards quantifying density and temperature from campaign spectroscopic data, we establish the three-dimensional morphology of the cavity. This is critical for taking line-of-sight projection effects into account, since cavities are not localized in the plane of the sky and the corona is optically thin. We have augmented a global coronal streamer model to include a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel length. We have developed a semi-automated routine that fits ellipses to cross-sections of the cavity as it rotates past the solar limb, and have applied it to Extreme Ultraviolet Imager (EUVI) observations from the two Solar Terrestrial Relations Observatory (STEREO) spacecraft. This defines the morphological parameters of our model, from which we reproduce forward-modeled cavity observables. We find that cavity morphology and orientation, in combination with the viewpoints of the observing spacecraft, explains the observed variation in cavity visibility for the east vs. west limbs

  6. Isolation of intact sub-dermal secretory cavities from Eucalyptus

    Directory of Open Access Journals (Sweden)

    Goodger Jason QD

    2010-09-01

    Full Text Available Abstract Background The biosynthesis of plant natural products in sub-dermal secretory cavities is poorly understood at the molecular level, largely due to the difficulty of physically isolating these structures for study. Our aim was to develop a protocol for isolating live and intact sub-dermal secretory cavities, and to do this, we used leaves from three species of Eucalyptus with cavities that are relatively large and rich in essential oils. Results Leaves were digested using a variety of commercially available enzymes. A pectinase from Aspergillus niger was found to allow isolation of intact cavities after a relatively short incubation (12 h, with no visible artifacts from digestion and no loss of cellular integrity or cavity contents. Several measurements indicated the potential of the isolated cavities for further functional studies. First, the cavities were found to consume oxygen at a rate that is comparable to that estimated from leaf respiratory rates. Second, mRNA was extracted from cavities, and it was used to amplify a cDNA fragment with high similarity to that of a monoterpene synthase. Third, the contents of the cavity lumen were extracted, showing an unexpectedly low abundance of volatile essential oils and a sizeable amount of non-volatile material, which is contrary to the widely accepted role of secretory cavities as predominantly essential oil repositories. Conclusions The protocol described herein is likely to be adaptable to a range of Eucalyptus species with sub-dermal secretory cavities, and should find wide application in studies of the developmental and functional biology of these structures, and the biosynthesis of the plant natural products they contain.

  7. Commensal communism and the oral cavity.

    Science.gov (United States)

    Henderson, B; Wilson, M

    1998-09-01

    The world we live in contains unimaginable numbers of bacteria, and these and other single-celled creatures represent the major diversity of life on our planet. During the last decade or so, the complexity and intimacy of the interactions which occur between bacteria and host eukaryotic cells during the process of infection have begun to emerge. The study of such interactions is the subject of the new discipline of cellular microbiology. This intimacy of bacteria/host interactions creates a major paradox. The average human being is 90% bacteria in terms of cell numbers. These bacteria constitute the commensal or normal microflora and populate the mucosal surfaces of the oral cavity, gastrointestinal tract, urogenital tract, and the surface of the skin. In bacterial infections, much of the pathology is due to the release of a range of bacterial components (e.g., modulins such as lipopolysaccharide, peptidoglycan, DNA, molecular chaperones), which induce the synthesis of the local hormone-like molecules known as pro-inflammatory cytokines. However, such components must also be constantly released by the vast numbers of bacteria constituting the normal microflora and, as a consequence, our mucosae should constantly be in a state of inflammation. This is patently not the case, and a hypothesis is forwarded to account for this "commensal paradox", namely, that our commensal bacteria and mucosal surfaces exist in a state of bio-communism, forming a unified "tissue" in which interactions between bacteria and epithelia are finely balanced to ensure bacterial survival and prevent the induction of damaging inflammation. Evidence is emerging that bacteria can produce a variety of proteins which can inhibit the synthesis/release of inflammatory cytokines. The authors predict that such proteins are simply one part of an extensive signaling system which occurs between bacteria and epithelial cells at mucosal surfaces such as those found in the oral cavity.

  8. Scintillation-Hardened GPS Receiver

    Science.gov (United States)

    Stephens, Donald R.

    2015-01-01

    CommLargo, Inc., has developed a scintillation-hardened Global Positioning System (GPS) receiver that improves reliability for low-orbit missions and complies with NASA's Space Telecommunications Radio System (STRS) architecture standards. A software-defined radio (SDR) implementation allows a single hardware element to function as either a conventional radio or as a GPS receiver, providing backup and redundancy for platforms such as the International Space Station (ISS) and high-value remote sensing platforms. The innovation's flexible SDR implementation reduces cost, weight, and power requirements. Scintillation hardening improves mission reliability and variability. In Phase I, CommLargo refactored an open-source GPS software package with Kalman filter-based tracking loops to improve performance during scintillation and also demonstrated improved navigation during a geomagnetic storm. In Phase II, the company generated a new field-programmable gate array (FPGA)-based GPS waveform to demonstrate on NASA's Space Communication and Navigation (SCaN) test bed.

  9. Dynamic resonance of light in Fabry-Perot cavities

    International Nuclear Information System (INIS)

    Rakhmanov, M.; Savage, R.L.; Reitze, D.H.; Tanner, D.B.

    2002-01-01

    The dynamics of light in Fabry-Perot cavities with varying length and input laser frequency are analyzed. At high frequencies, the response to length variations is very different from the response to laser frequency variations. Implications for kilometer-scale Fabry-Perot cavities such as those utilized in gravitational-wave detectors are discussed

  10. Short Note Ground cavity nest temperatures and their relevance to ...

    African Journals Online (AJOL)

    Blue Swallows Hirundo atrocaerulea are Critically Endangered within South Africa. They nest in natural underground holes in mist-belt grasslands. Temperature dataloggers were used to record ground cavity nest (Tn) and ambient temperature (Ta) for one artificial and 11 natural Blue Swallow nests. Mean ground cavity Tn ...

  11. Toward more accurate loss tangent measurements in reentrant cavities

    Energy Technology Data Exchange (ETDEWEB)

    Moyer, R. D.

    1980-05-01

    Karpova has described an absolute method for measurement of dielectric properties of a solid in a coaxial reentrant cavity. His cavity resonance equation yields very accurate results for dielectric constants. However, he presented only approximate expressions for the loss tangent. This report presents more exact expressions for that quantity and summarizes some experimental results.

  12. High-R Walls for Remodeling. Wall Cavity Moisture Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Wiehagen, J. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Kochkin, V. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States)

    2012-12-01

    The focus of the study is on the performance of wall systems, and in particular, the moisture characteristics inside the wall cavity and in the wood sheathing. Furthermore, while this research will initially address new home construction, the goal is to address potential moisture issues in wall cavities of existing homes when insulation and air sealing improvements are made.

  13. Analysis of adiabatic transfer in cavity quantum electrodynamics

    Indian Academy of Sciences (India)

    A three-level atom in a configuration trapped in an optical cavity forms a basic unit in a number of proposed protocols for quantum information processing. This system allows for efficient storage of cavity photons into long-lived atomic excitations, and their retrieval with high fidelity, in an adiabatic transfer process through ...

  14. Ultrafast Dynamics of Vibration-Cavity Polariton Modes

    Science.gov (United States)

    Owrutsky, Jeff; Dunkelberger, Adam; Fears, Kenan; Simpkins, Blake; Spann, Bryan

    Vibrational modes of polymers, liquids, and solvated compounds can couple to Fabry-Perot optical cavity modes, creating vibration-cavity polariton modes whose energy tunes with the cavity length and incidence angle. Here we report the pump-probe infrared spectroscopy of vibration-cavity polaritons in cavity-coupled W(CO)6. At very early times, we observe quantum beating between the two polariton states find an anomalously low degree of excitation. After the quantum beating, we directly observe spectroscopic signatures of excited-state absorption from both polariton modes and uncoupled reservoir modes. An analytical expression for cavity transmission reproduces these signatures. The upper polariton mode relaxes ten times more quickly than the uncoupled vibrational mode and the polariton lifetime depends on the angle of incidence of the infrared pulses. Coupling to an optical cavity gives a means of control of the lifetime of vibration-cavity polaritons and could have important implications for chemical reactivity in vibrationally excited molecules.

  15. High-R Walls for Remodeling: Wall Cavity Moisture Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Wiehagen, J.; Kochkin, V.

    2012-12-01

    The focus of the study is on the performance of wall systems, and in particular, the moisture characteristics inside the wall cavity and in the wood sheathing. Furthermore, while this research will initially address new home construction, the goal is to address potential moisture issues in wall cavities of existing homes when insulation and air sealing improvements are made.

  16. Manufacturing of the L band 9-cell niobium cavity

    International Nuclear Information System (INIS)

    Matsuoka, Masanori; Ohkubo, Kohichi; Yamanaka, Toshiyuki; Kako, Eiji; Saito, Kenji; Shishido, Toshio; Ono, Masaaki; Noguchi, Shuichi.

    1993-01-01

    Since 1990, L-band niobium superconducting cavities have been developed with collaboration between our company and National Laboratory for High Energy Physics (KEK). The manufacturing procedure and the performance of 9-cell superconducting cavity are presented. The maximum accelerating gradient of 12 MV/m was attained in a cold test. (author)

  17. Cavity Ring-down Spectroscopic System And Method

    KAUST Repository

    Alquaity, Awad Bin Saud

    2015-05-14

    A system and method for cavity ring-down spectroscopy can include a pulsed quantum cascade laser, an optical ring-down cavity, a photodetector, and an oscilloscope. The system and method can produce pulse widths of less than 200 ns with bandwidths greater than 300 pm, as well as provide temporal resolution of greater than 10 .mu.s.

  18. Tree structure and cavity microclimate: implications for bats and birds.

    Science.gov (United States)

    Clement, Matthew J; Castleberry, Steven B

    2013-05-01

    It is widely assumed that tree cavity structure and microclimate affect cavity selection and use in cavity-dwelling bats and birds. Despite the interest in tree structure and microclimate, the relationship between the two has rarely been quantified. Currently available data often comes from artificial structures that may not accurately represent conditions in natural cavities. We collected data on tree cavity structure and microclimate from 45 trees in five cypress-gum swamps in the Coastal Plain of Georgia in the United States in 2008. We used hierarchical linear models to predict cavity microclimate from tree structure and ambient temperature and humidity, and used Aikaike's information criterion to select the most parsimonious models. We found large differences in microclimate among trees, but tree structure variables explained 80% of variation common to all trees. We argue that the determinants of microclimate are complex and multidimensional, and therefore cavity microclimate cannot be deduced easily from simple tree structures. Furthermore, we found that daily fluctuations in ambient conditions strongly affect microclimate, indicating that greater weather fluctuations will cause greater differences among tree cavities.

  19. [Stafne's cavity. Review and apropos of 6 cases].

    Science.gov (United States)

    Grau Cases, J; Gay Escoda, C; Hernández Alfaro, F

    1991-02-01

    A retrospective study of 6 cases of Stafne's static cavities is presented in a review of 1536 cases of maxillary cysts. We have found an incidence 4:2 for men. All cases have been detected casually. The sialography show a relationship between cavities and the submaxillary gland. The treatment was surgical in four cases and conservative in two.

  20. On unsteady reacting flow in a channel with a cavity

    Directory of Open Access Journals (Sweden)

    Ivar Ø. Sand

    1991-10-01

    Full Text Available The problem investigated is the stability of a flame anchored by recirculation within a channel with a cavity, acting as a two-dimensional approximation to a gas turbine combustion chamber. This is related to experiments of Vaneveld, Hom and Oppenheim (1982. The hypothesis studied is that hydrodynamic oscillations within the cavity can lead to flashback.

  1. A generic travelling wave solution in dissipative laser cavity

    Indian Academy of Sciences (India)

    2016-09-09

    Sep 9, 2016 ... Abstract. A large family of cosh-Gaussian travelling wave solution of a complex Ginzburg–Landau equation. (CGLE), that describes dissipative semiconductor laser cavity is derived. Using perturbation method, the stabil- ity region is identified. Bifurcation analysis is done by smoothly varying the cavity loss ...

  2. Single-cell LEP-type cavity on measurement stand

    CERN Multimedia

    CERN PhotoLab

    1982-01-01

    A single-cell cavity, made of copper, with tapered connectors for impedance measurements. It was used as a model of LEP-type superconducting cavities, to investigate impedance and higher-order modes and operated at around 600 MHz (the LEP acceleration frequency was 352.2 MHz). See 8202500.

  3. Integral storage-bulb and microwave cavity for masers

    Science.gov (United States)

    Reinhardt, V. S.

    1980-01-01

    Mechanically-stable integral storage-bulb/microwave cavity made out of single piece of fused quartz improves frequency stability. Single-piece construction eliminates joints, making cavity dimensionally and hence frequency-stable. Fused quartz is used because of its low thermal expansion coefficient.

  4. Biological and chemical characteristics of the coral gastric cavity

    Science.gov (United States)

    Agostini, S.; Suzuki, Y.; Higuchi, T.; Casareto, B. E.; Yoshinaga, K.; Nakano, Y.; Fujimura, H.

    2012-03-01

    All corals have a common structure: two tissue layers enclose a lumen, which forms the gastric cavity. Few studies have described the processes occurring inside the gastric cavity and its chemical and biological characteristics. Here, we show that the coral gastric cavity has distinct chemical characteristics with respect to dissolved O2, pH, alkalinity, and nutrients (vitamin B12, nitrate, nitrite, ammonium, and phosphate) and also harbors a distinct bacterial community. From these results, the gastric cavity can be described as a semi-closed sub-environment within the coral. Dissolved O2 shows very low constant concentrations in the deepest parts of the cavity, creating a compartmentalized, anoxic environment. The pH is lower in the cavity than in the surrounding water and, like alkalinity, shows day/night variations different from those of the surrounding water. Nutrient concentrations in the cavity are greater than the concentrations found in reef waters, especially for phosphate and vitamin B12. The source of these nutrients may be internal production by symbiotic bacteria and/or the remineralization of organic matter ingested or produced by the corals. The importance of the bacteria inhabiting the gastric cavity is supported by the finding of a high bacterial abundance and a specific bacterial community with affiliation to bacteria found in other corals and in the guts of other organisms. The findings presented here open a new area of research that may help us to understand the processes that maintain coral health.

  5. RF cavity using liquid dielectric for tuning and cooling

    Science.gov (United States)

    Popovic, Milorad [Warrenville, IL; Johnson, Rolland P [Newport News, VA

    2012-04-17

    A system for accelerating particles includes an RF cavity that contains a ferrite core and a liquid dielectric. Characteristics of the ferrite core and the liquid dielectric, among other factors, determine the resonant frequency of the RF cavity. The liquid dielectric is circulated to cool the ferrite core during the operation of the system.

  6. High pressure discharges in cavities formed by microfabrication techniques

    International Nuclear Information System (INIS)

    Khan, B.A.; Cammack, D.A.; Pinker, R.D.; Racz, J.

    1997-01-01

    High pressure discharges are the basis of small high intensity light sources. In this work, we demonstrate the formation of high pressure discharges, in cavities formed by applying micromachining and integrated circuit techniques to quartz substrates. Cavities containing varying amounts of mercury and argon were fabricated to obtain high pressure discharges. A high pressure mercury discharge was formed in the electrodeless cavities by exciting them with a microwave source, operating at 2.45 GHz and in the electroded cavities by applying a dc voltage. The contraction of the discharge into a high pressure arc was observed. A broad emission spectrum due to self-absorption and collisions between excited atoms and normal atoms, typical of high pressure mercury discharges, was measured. The light output and efficacy increased with increasing pressure. The measured voltage was used to estimate the pressure within the electroded cavities, which is as high as 127 atm for one of the two cavities discussed in this work. Efficacies over 40 lumens per watt were obtained for the electrodeless cavities and over 50 scr(l)m/W for the electroded cavities. copyright 1997 American Institute of Physics

  7. Nasal cavity of the farmed african catfish Clarias gariepinus ...

    African Journals Online (AJOL)

    The nasal cavity microanatomy of farmed fingerlings of African catfish, Clarias gariepunus was investigated to fill existing knowledge gap on its histology from available literatures. This becomes very important as no gustatory cell was reported from previous researches on the fingerling digestive tract. A slice of nasal cavity of ...

  8. Polarisation dynamics of a birefringent Fabry-Perot cavity

    Science.gov (United States)

    Ejlli, A.; Della Valle, F.; Zavattini, G.

    2018-02-01

    Optical Fabry-Perot cavities always show a non-degeneracy of two orthogonal polarisation states. This is due to the unavoidable birefringence of dielectric mirrors whose effects are extremely important in Fabry-Perot-based high-accuracy polarimeters: in birefringent cavities, ellipticities and rotations mix. We have developed and present here a theory of the polarisation state dynamics in a birefringent Fabry-Perot resonator, and we validate it through measurements performed with the polarimeter of the PVLAS experiment. The measurements are performed while a laser is frequency-locked to the cavity, and provide values for the phase difference between the two orthogonal polarisation components introduced by the combination of the two cavity mirrors (equivalent wave-plate) and for the finesse of the cavity. The theoretical formulas and the experimental data agree well showing that the consequences of the mirror birefringence must be taken into account in this and in any other similar experiment.

  9. Dependence of transmon qubit relaxation rate on cavity photon population

    Science.gov (United States)

    Mundhada, S. O.; Shankar, S.; Liu, Y.; Hatridge, M.; Narla, A.; Sliwa, K. M.; Girvin, S. M.; Devoret, M. H.

    2015-03-01

    In circuit QED experiments, a qubit is dispersively coupled to a cavity such that the cavity frequency depends on the qubit state. This dispersive shift enables quantum non-demolition readout of the qubit by exciting the cavity with a microwave pulse and detecting the phase shift of the reflected signal. However, this cavity excitation has been observed in experiments to increase the qubit relaxation rate, hence demolishing the qubit state and limiting the maximum measurement strength. Here we experimentally study this effect in a transmon qubit coupled to a three-dimensional superconducting cavity. We also explore alternate qubit circuits designed to mitigate this demolition effect. Work supported by: IARPA, ARO, and NSF.

  10. A Pass Band Performance Simulation Code of Coupled Cavities

    CERN Document Server

    Tao, X

    2004-01-01

    A simulation code of accelerating cavities named PPSC is developed by the solutions of the microwave equivalent circuit equations. PPSC can give the pass band performance of periodic or non-periodic accelerating structures, such as the dispersion frequency and the reflection factor of the cavity, the field distribution of each mode and so on. The natural parameters of the structure, such as the number of the cavities, the resonant frequencies and Q-factors of each cavity, the coupling factor between two cavities, and the locations of the couplers, can be changed easily to see the different results of the simulation. The code is written based on MS Visual Basic under MS windows. With these, a user-friendly interface is made. Some simple examples was simulated and gave reliable results.

  11. Cavity formation by the impact of Leidenfrost spheres

    KAUST Repository

    Marston, Jeremy

    2012-05-01

    We report observations of cavity formation and subsequent collapse when a heated sphere impacts onto a liquid pool. When the sphere temperature is much greater than the boiling point of the liquid, we observe an inverted Leidenfrost effect where the sphere is encompassed by a vapour layer that prevents physical contact with the liquid. This creates the ultimate non-wetting scenario during sphere penetration through a free surface, producing very smooth cavity walls. In some cases during initial entry, however, the liquid contacts the sphere at the equator, leading to the formation of a dual cavity structure. For cold sphere impacts, where a contact line is observed, we reveal details of the contact line pinning, which initially forms a sawtooth pattern. We also observe surface waves on the cavity interface for cold spheres. We compare our experimental results to previous studies of cavity dynamics and, in particular, the influence of hydrophobicity on the entry of the sphere. © 2012 Cambridge University Press.

  12. Cavity preparation machine for the standardization of in vitro preparations

    Directory of Open Access Journals (Sweden)

    Carlos José Soares

    2008-09-01

    Full Text Available Several in vitro studies employ the confection of cavity preparations that are difficult to standardize by means of manual high speed handpieces. This study presents the development of a cavity preparation machine designed to standardize in vitro cavity preparations. A metal base of 25 mm x 25 mm x 4 mm (length x width x height was coupled to a small mobile table which was designed to be able to move by means of two precision micrometers (0.01-mm accuracy in the horizontal directions (right-left, and back-front. A high speed handpiece was coupled to a metallic connecting rod which had an accurate dial indicator enabling control of the vertical movement. The high speed handpiece is also able to move 180° around its longitudinal axis and 360° around its transversal axis. The suggested cavity preparation machine precisely helps in the standardization of cavity preparations for in vitro studies.

  13. Novel High Cooperativity Photon-Magnon Cavity QED

    Science.gov (United States)

    Tobar, Michael; Bourhill, Jeremy; Kostylev, Nikita; G, Maxim; Creedon, Daniel

    Novel microwave cavities are presented, which couple photons and magnons in YIG spheres in a super- and ultra-strong way at around 20 mK in temperature. Few/Single photon couplings (or normal mode splitting, 2g) of more than 6 GHz at microwave frequencies are obtained. Types of cavities include multiple post reentrant cavities, which co-couple photons at different frequencies with a coupling greater that the free spectral range, as well as spherical loaded dielectric cavity resonators. In such cavities we show that the bare dielectric properties can be obtained by polarizing all magnon modes to high energy using a 7 Tesla magnet. We also show that at zero-field, collective effects of the spins significantly perturb the photon modes. Other effects like time-reversal symmetry breaking are observed.

  14. Complex envelope control of pulsed accelerating fields in superconducting cavities

    CERN Document Server

    Czarski, T

    2010-01-01

    A digital control system for superconducting cavities of a linear accelerator is presented in this work. FPGA (Field Programmable Gate Arrays) based controller, managed by MATLAB, was developed to investigate a novel firmware implementation. The LLRF - Low Level Radio Frequency system for FLASH project in DESY is introduced. Essential modeling of a cavity resonator with signal and power analysis is considered as a key approach to the control methods. An electrical model is represented by the non-stationary state space equation for the complex envelope of the cavity voltage driven by the current generator and the beam loading. The electromechanical model of the superconducting cavity resonator including the Lorentz force detuning has been developed for a simulation purpose. The digital signal processing is proposed for the field vector detection. The field vector sum control is considered for multiple cavities driven by one klystron. An algebraic, complex domain model is proposed for the system analysis. The c...

  15. Millimeter-long fiber Fabry-Perot cavities.

    Science.gov (United States)

    Ott, Konstantin; Garcia, Sebastien; Kohlhaas, Ralf; Schüppert, Klemens; Rosenbusch, Peter; Long, Romain; Reichel, Jakob

    2016-05-02

    We demonstrate fiber Fabry-Perot (FFP) cavities with concave mirrors that can be operated at cavity lengths as large as 1.5 mm without significant deterioration of the finesse. This is achieved by using a laser dot machining technique to shape spherical mirrors with ultralow roughness and employing single-mode fibers with large mode area for good mode matching to the cavity. Additionally, in contrast to previous FFPs, these cavities can be used over an octave-spanning frequency range with adequate coatings. We also show directly that shape deviations caused by the fiber's index profile lead to a finesse decrease as observed in earlier attempts to build long FFP cavities, and show a way to overcome this problem.

  16. Heat transfer in window frames with internal cavities

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsen, Arild

    2001-07-01

    Heat transfer in window frames with internal air cavities is studied in this thesis. Investigations focus on two- and three-dimensional natural convection effects inside air cavities, the dependence of the emissivity on the thermal transmittance, and the emissivity of anodized and untreated aluminium profiles. The investigations are mostly conducted on window frames which are the same size as real frames found in residential buildings. Numerical and experimental investigations were performed to study the effectiveness of one commercial Computational Fluid Dynamics (CFD) program for simulating combined natural convection and heat transfer in simple three-dimensional window frames with internal air cavities. The accuracy of the conjugate CFD simulations was evaluated by comparing results for surface temperature on the warm side of the specimens to results from experiments that use infrared (IR) thermography to map surface temperatures during steady-state thermal tests. In general, there was good agreement between the simulations and experiments. Two-dimensional computational fluid dynamic and conduction simulations are performed to study the difference between treating air cavities as a fluid and as a solid when calculating the thermal transmittance of window frames. The simulations show that traditional software codes, simulating only conduction and using equivalent conductivities for the air cavities, give Uvalues that compare well with results from fluid flow simulations. The difference between the two models are mostly limited to the temperature distribution inside air cavities. It is also found that cavities with an interconnection less than about 7 mm can be treated as separate cavities. Three-dimensional natural convection effects in simple and custom-made PVC and thermally broken aluminum window frames with one open internal cavity were studied, with the use of CFD simulations and thermography experiments. Focus was put on corner effects and heat transfer

  17. Researches on bake effect on RF superconducting cavities

    International Nuclear Information System (INIS)

    Hao Jiankui; Zhao Kui; Zhu Feng

    2005-01-01

    The Q-slope at high gradient affects the performance of superconducting cavity greatly. Recent researches show that low temperature (100-150) degree C heat treatment (bake) has positive effects on the performance of superconducting cavities. A lot of cavity tests are analyzed based on bake treatment. The average gradient E acc,max and E acc at Q=1 x 10 10 are increased by more than 3.5 MV/m. Q at E acc,max is increased and the Q-slope is improved. Analysis on bake temperature shows that higher bake temperature leads to higher Q value. Comparison of BCP and EP cavities shows that at least 60-80 μm EP is needed for BCP surface. More than 10-15 μm removal of the surface by BCP will degrade the performance of an EP cavity. Oxygen diffusion model is used to illustrate bake effect. (authors)

  18. Metastatic Tumours to the Oral Cavity: Report of Three Cases

    Directory of Open Access Journals (Sweden)

    Ioanna G. Kalaitsidou

    2015-12-01

    Full Text Available Background: Metastatic tumours to the oral cavity from distant organs are uncommon and represent approximately 1 - 3% of all oral malignancies. Such metastases can occur to the bone or to the oral soft tissues. Almost any malignancy from any site is capable of metastasis to the oral cavity and a wide variety of tumours have been reported to spread to the mouth. Methods: Careful examination of the oral cavity and a high degree of clinical suspicion as well as a multidisciplinary approach are suggested. Results: In this article we present three patients, a female and two males with metastatic tumours to the oral cavity, who were referred to our Department. The primary tumours were invasive lobular breast carcinoma, gastric adenocarcinoma and small cell lung carcinoma respectively. Conclusions: Metastases to the oral cavity are quite uncommon among population. They usually present with symptoms similar to odontogenic infections and benign tumours, causing a delayed diagnosis and treatment.

  19. Temperature Mapping of Nitrogen-doped Niobium Superconducting Radiofrequency Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Makita, Junki [Old Dominion Univ., Norfolk, VA (United States); Ciovati, Gianluigi [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Dhakal, Pashupati [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    It was recently shown that diffusing nitrogen on the inner surface of superconducting radiofrequency (SRF) cavities at high temperature can improve the quality factor of the niobium cavity. However, a reduction of the quench field is also typically found. To better understand the location of rf losses and quench, we used a thermometry system to map the temperature of the outer surface of ingot Nb cavities after nitrogen doping and electropolishing. Surface temperature of the cavities was recorded while increasing the rf power and also during the quenching. The results of thermal mapping showed no precursor heating on the cavities and quenching to be ignited near the equator where the surface magnetic field is maximum. Hot-spots at the equator area during multipacting were also detected by thermal mapping.

  20. Apparatus and process for passivating an SRF cavity

    Science.gov (United States)

    Myneni, Ganapati Rao; Wallace, John P

    2014-12-02

    An apparatus and process for the production of a niobium cavity exhibiting high quality factors at high gradients is provided. The apparatus comprises a first chamber positioned within a second chamber, an RF generator and vacuum pumping systems. The process comprises placing the niobium cavity in a first chamber of the apparatus; thermally treating the cavity by high temperature in the first chamber while maintaining high vacuum in the first and second chambers; and applying a passivating thin film layer to a surface of the cavity in the presence of a gaseous mixture and an RF field. Further a niobium cavity exhibiting high quality factors at high gradients produced by the method of the invention is provided.

  1. Magnetic Flux Expulsion Studies in Niobium SRF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Posen, Sam [Fermilab; Checchin, Mattia [Fermilab; Crawford, Anthony [Fermilab; Grassellino, Anna [Fermilab; Martinello, Martina [Fermilab; Melnychuk, Oleksandr [Fermilab; Romanenko, Alexander [Fermilab; Sergatskov, Dmitri [Fermilab; Trenikhina, Yulia [Fermilab

    2016-06-01

    With the recent discovery of nitrogen doping treatment for SRF cavities, ultra-high quality factors at medium accelerating fields are regularly achieved in vertical RF tests. To preserve these quality factors into the cryomodule, it is important to consider background magnetic fields, which can become trapped in the surface of the cavity during cooldown and cause Q₀ degradation. Building on the recent discovery that spatial thermal gradients during cooldown can significantly improve expulsion of magnetic flux, a detailed study was performed of flux expulsion on two cavities with different furnace treatments that are cooled in magnetic fields amplitudes representative of what is expected in a realistic cryomodule. In this contribution, we summarize these cavity results, in order to improve understanding of the impact of flux expulsion on cavity performance.

  2. Treatment outcome of advance staged oral cavity cancer: concurrent chemoradiotherapy compared with primary surgery.

    Science.gov (United States)

    Tangthongkum, Manupol; Kirtsreesakul, Virat; Supanimitjaroenporn, Pasawat; Leelasawatsuk, Peesit

    2017-06-01

    Concurrent chemoradiotherapy (CCRT) has been reported as effective and has become an acceptable treatment in advanced oral cancer. However, to date there is insufficient data to conclude that CCRT provides a good survival outcome. The purpose of this study was to compare survival rates and complications in patients with resectable advanced oral cavity squamous cell carcinoma treated with either CCRT or surgery with adjuvant radiotherapy (RT)/chemoradiotherapy (CRT). Stage III or IVa oral cavity carcinoma patients treated with curative intent by either CCRT or surgery with adjuvant RT were identified over a 7-year period (2009-2015). Survival rates and treatment complications were analyzed and compared between the two groups. 61 patients underwent CCRT and 128 patients underwent surgical excision and received postoperative RT. There was no statistically significant difference in survival outcome between the two treatment groups. 5-year overall survival rates (OS) were 33 versus 24% (P = 0.191) and the disease-specific survival rates (DSS) were 27 versus 25% (P = 0.857) when comparing the CCRT group and surgery with adjuvant RT/CRT group, respectively. Long-term complications were comparable between the two groups. CCRT has comparable survival outcome and complications for the treatment of advanced oral cavity squamous cell carcinoma, compared to surgery with adjuvant RT/CRT.

  3. Intensity-Modulated Radiotherapy in Postoperative Treatment of Oral Cavity Cancers

    International Nuclear Information System (INIS)

    Gomez, Daniel R.; Zhung, Joanne E.; Gomez, Jennifer; Chan, Kelvin; Wu, Abraham J.; Wolden, Suzanne L.; Pfister, David G.; Shaha, Ashok; Shah, Jatin P.; Kraus, Dennis H.; Wong, Richard J.; Lee, Nancy Y.

    2009-01-01

    Purpose: To present our single-institution experience of intensity-modulated radiotherapy (IMRT) for oral cavity cancer. Methods and Materials: Between September 2000 and December 2006, 35 patients with histologically confirmed squamous cell carcinoma of the oral cavity underwent surgery followed by postoperative IMRT. The sites included were buccal mucosa in 8, oral tongue in 11, floor of the mouth in 9, gingiva in 4, hard palate in 2, and retromolar trigone in 1. Most patients had Stage III-IV disease (80%). Ten patients (29%) also received concurrent postoperative chemotherapy with IMRT. The median prescribed radiation dose was 60 Gy. Results: The median follow-up for surviving patients was 28.1 months (range, 11.9-85.1). Treatment failure occurred in 11 cases as follows: local in 4, regional in 2, and distant metastases in 5. Of the 5 patients with distant metastases, 2 presented with dermal metastases. The 2- and 3-year estimates of locoregional progression-free survival, distant metastasis-free survival, disease-free survival, and overall survival were 84% and 77%, 85% and 85%, 70% and 64%, and 74% and 74%, respectively. Acute Grade 2 or greater dermatitis, mucositis, and esophageal reactions were experienced by 54%, 66%, and 40% of the patients, respectively. Documented late complications included trismus (17%) and osteoradionecrosis (5%). Conclusion: IMRT as an adjuvant treatment after surgical resection for oral cavity tumors is feasible and effective, with promising results and acceptable toxicity

  4. Nanohybrid vs. fine hybrid composite in extended class II cavities: 8-year results.

    Science.gov (United States)

    Frankenberger, Roland; Reinelt, Christian; Krämer, Norbert

    2014-01-01

    In a controlled prospective split-mouth study, clinical behavior of two different resin composites in extended class II cavities was observed over 8 years. Thirty patients received 68 direct resin composite restorations (Solobond M/Grandio, Voco--n = 36; Syntac/Tetric Ceram, Ivoclar Vivadent--n = 32) by one dentist in a private practice. Thirty-five percent of cavities revealed no enamel at the bottom of the proximal box, 48% of cavities provided Grandio restoration was lost due to bulk fracture. One Tetric Ceram restoration suffered drop out due to cusp fracture having been not related to the restoration itself. Neither restorative materials nor localization of the restorations had a significant influence on any criterion except color (darker for Grandio). Restorations in molars performed inferior compared with premolars regarding marginal integrity (4 years), restoration integrity (6, 12, 24, 48, and 96 months), and tooth integrity (12, 48, 72, and 96 months). Irrespective of the resin composite used, significant changes over time were found for all criteria evaluated in clinical examinations. Beyond the 4-year recall, marginal staining increased. Both phenomena were found earlier in molars compared with premolars. Tooth integrity significantly deteriorated because of increasing enamel cracks and chippings over time. Both materials performed satisfactorily over the 8-year observation period. Due to the extension of the restorations, wear was clearly visible after 8 years of clinical service. Hybrid and nanohybrid resin composites show an acceptable clinical performance after 8 years of service.

  5. Developmental changes in primary cilia in the mouse tooth germ and oral cavity.

    Science.gov (United States)

    Hisamoto, Meri; Goto, Marie; Muto, Mami; Nio-Kobayashi, Junko; Iwanaga, Toshihiko; Yokoyama, Atsuro

    2016-01-01

    The primary cilium, a sensory apparatus, functions as both a chemical and mechanical sensor to receive environmental stimuli. The present study focused on the primary cilia in the epithelialmesenchymal interaction during tooth development. We examined the localization and direction of projection of primary cilia in the tooth germ and oral cavity of mice by immunohistochemical observation. Adenylyl cyclase 3 (ACIII)-immunolabeled cilia were visible in the inner/outer enamel epithelium of molars at the fetal stage and then conspicuously developed in the odontoblast layer postnatally. The primary cilia in ameloblasts and odontoblasts-shown by the double staining of acetylated tubulin and γ-tubulin-were regularly arranged from postnatal Day12, projecting apart from each other. The periodontal ligament possessed ACIII-positive cilia, which gathered on both sides of the dentin/cement and alveolar bone in postnatal days. In the oral cavity, numerous long primary cilia immunoreactive for ACIII were condensed at subepithelial stromal cells in the oral processes in fetuses, while postnatally a small number of short cilia were dispersed throughout the stroma of the oral cavity. These findings suggest that the primary cilia showing stage- and regionspecific morphology are involved in the epithelial-mesenchymal interaction during tooth development via mechano- and/or chemoreception for growth factors.

  6. Communication received from South Africa

    International Nuclear Information System (INIS)

    1984-02-01

    The document reproduces the press release with a statement by Dr. J.W.L. de Villiers, Executive Chairman of the Atomic Energy Corporation of South Africa Limited, issued on 31 January 1984 and included in the letter received by the Director General of the IAEA from the Resident Representative of South Africa to the Agency on 31 January 1984. This statement refers to the transfer of nuclear material equipment and technology by South Africa to other countries and the Non-Proliferation Treaty

  7. Perception of dental illness among persons receiving public assistance in Montreal.

    Science.gov (United States)

    Bedos, Christophe; Brodeur, Jean-Marc; Levine, Alissa; Richard, Lucie; Boucheron, Laurence; Mereus, Witnisse

    2005-08-01

    We examined rationales for behaviors related to dental care among persons receiving public assistance in Montreal, Quebec. Fifty-seven persons receiving public assistance participated in 8 focus groups conducted in 2002. Sessions were recorded on audiotape and transcribed; analyses included debriefing sessions and coding and interpreting transcribed data. In the absence of dental pain and any visible cavity, persons receiving public assistance believed they were free of dental illness. However, they knew that dental pain signals a pathological process that progressively leads to tooth decay and, therefore, should be treated by a dentist. However, when in pain, despite recognizing that they needed professional treatment, they preferred to wait and suffer because of a fear of painful dental treatments and a reluctance to undertake certain procedures. Persons receiving public assistance have perceptions about dental health and illness that prevent them from receiving early treatment for tooth decay, which may lead to disagreements with dentists when planning dental treatments.

  8. Superconducting Prototype Cavities for the Spallation Neutron Source (SNS) Project

    International Nuclear Information System (INIS)

    Ciovati, G.; Kneisel, P.; Brawley, J.; Bundy, R.; Campisi, I.; Davis, K.; Macha, K.; Machie, D.; Mammosser, J.; Morgan, S.; Sundelin, R.; Turlington, L.; Wilson, K.; Doleans, M.; Kim, S.H.; Barni, D.; Pagani, C.; Pierini, P.; Matsumoto, K.; Mitchell, R.; Schrage, D.; Parodi, R.; Sekutowicz, J.; Ylae-Oijala, P.

    2001-01-01

    The Spallation Neutron Source project includes a superconducting linac section in the energy range from 192 MeV to 1000 MeV, operating at a frequency of 805 MHz at 2.1 K. For this energy range two types of cavities are needed with geometrical beta - values of beta= 0.61 and beta= 0.81. An aggressive cavity prototyping program is being pursued at Jlab, which calls for fabricating and testing of four beta= 0.61 cavities and two beta= 0.81 cavities. Both types consist of six cells made from high purity niobium and feature one HOM coupler on each beam pipe and a port for a high power coaxial input coupler. Three of the four beta= 0.61 cavities will be used for a cryomodule test in early 2002. At this time four medium beta cavities and one high beta cavity have been completed at JLab. The first tests on the beta=0.61 cavity and the beta= 0.81 exceeded the design values for gradient and Q - value: E acc = 1 0.3 MV/m and Q = 5 x 10 9 at 2.1K for beta= 0.61 and E acc = 12.3 MV/m and Q = 5 x 10 9 at 2.1K for beta= 0.81. One of the medium beta cavities has been equipped with an integrated helium vessel and measurements of the static and dynamic Lorentz force detuning will be done and compared to the ''bare'' cavities. In addition two single cell cavities have been fabricated, equipped with welded-on HOM couplers. They are being used to evaluate the HOM couplers with respect to multipacting, fundamental mode rejection and HOM damping as far as possible in a single cell. This paper will describe the cavity design with respect to electrical and mechanical features, the fabrication efforts and the results obtained with the different cavities existing at the time of this workshop

  9. Broadband direct RF digitization receivers

    CERN Document Server

    Jamin, Olivier

    2014-01-01

    This book discusses the trade-offs involved in designing direct RF digitization receivers for the radio frequency and digital signal processing domains.  A system-level framework is developed, quantifying the relevant impairments of the signal processing chain, through a comprehensive system-level analysis.  Special focus is given to noise analysis (thermal noise, quantization noise, saturation noise, signal-dependent noise), broadband non-linear distortion analysis, including the impact of the sampling strategy (low-pass, band-pass), analysis of time-interleaved ADC channel mismatches, sampling clock purity and digital channel selection. The system-level framework described is applied to the design of a cable multi-channel RF direct digitization receiver. An optimum RF signal conditioning, and some algorithms (automatic gain control loop, RF front-end amplitude equalization control loop) are used to relax the requirements of a 2.7GHz 11-bit ADC. A two-chip implementation is presented, using BiCMOS and 65nm...

  10. Design of an ammonia closed-loop storage system in a CSP power plant with a power tower cavity receiver

    Science.gov (United States)

    Abdiwe, Ramadan; Haider, Markus

    2017-06-01

    In this study the thermochemical system using ammonia as energy storage carrier is investigated and a transient mathematical model using MATLAB software was developed to predict the behavior of the ammonia closed-loop storage system including but not limited to the ammonia solar reactor and the ammonia synthesis reactor. The MATLAB model contains transient mass and energy balances as well as chemical equilibrium model for each relevant system component. For the importance of the dissociation and formation processes in the system, a Computational Fluid Dynamics (CFD) simulation on the ammonia solar and synthesis reactors has been performed. The CFD commercial package FLUENT is used for the simulation study and all the important mechanisms for packed bed reactors are taken into account, such as momentum, heat and mass transfer, and chemical reactions. The FLUENT simulation reveals the profiles inside both reactors and compared them with the profiles from the MATLAB code.

  11. Primary malignant melanoma of the nasal cavity.

    Science.gov (United States)

    Uysal, Ismail Önder; Misir, Mustafa; Polat, Kerem; Altuntaş, Emine Elif; Atalar, Mehmet Haydar; Tuncer, Ersin; Müderris, Suphi

    2012-01-01

    Primary malignant melanoma of the nose and paranasal sinus mucosa is a rare disease and seen in less than 1% among all melanomas. Malignant melanomas have 2 origins: cutaneous and mucosal. The mucosal form has a worse prognosis because of its aggressiveness compared with that of the cutaneous form. Mucosal melanomas often occur at a rate of 2% to 3% among all melanomas and are typically found in the nasal cavity and paranasal sinuses. Generally, it is more common in males and in those older than 50 years. In this study, 4 patients were observed at the Cumhuriyet University Faculty of Medicine; 2 of them were a 64-year-old man and an 82-year-old woman who had a malignant melanoma originating from the nasal septal mucosa, 1 patient was a 72-year-old woman whose malignant melanoma originated from the inferior turbinate, and 1 patient was a 77-year-old woman with a sinonasally located melanoma. The conditions of these patients were discussed under the light of literature instructions.

  12. Heat transfer in rotor/stator cavity

    Science.gov (United States)

    Tuliszka-Sznitko, Ewa; Majchrowski, Wojciech; Kiełczewski, Kamil

    2011-12-01

    In the paper we analyze the results of DNS/LES of the flow with heat transfer in the rotor/stator cavity. The rotor and the outer cylinder are heated. Computations have been performed for wide range of Reynolds numbers and aspect ratios. Computations are based on the efficient pseudo-spectral Chebyshev-Fourier method. In LES we used a Lagrangian dynamic subgrid-scale model of turbulence. Analysis allowed to check the influence of the aspect ratio and Reynolds number on the statistics and the structure of the flow. We analyzed all six Reynolds stress tensor components, turbulent fluctuations, three turbulent heat fluxes and different structural parameters which can be useful for modeling purposes. The distributions of Nusselt numbers obtained for different Re and aspect rations along disks are given. We also investigated influence of thermal Rosssby number as well as distributions of temperature along heated disk on statistics. Computations have shown that turbulence is mostly concentrated in the stator boundary layer with a maximum at the junction between the stator and the outer cylinder. The results are compared to the experimental and numerical data taken from literature.

  13. Dynamic Color Displays Using Stepwise Cavity Resonators.

    Science.gov (United States)

    Chen, Yiqin; Duan, Xiaoyang; Matuschek, Marcus; Zhou, Yanming; Neubrech, Frank; Duan, Huigao; Liu, Na

    2017-09-13

    High-resolution multicolor printing based on pixelated optical nanostructures is of great importance for promoting advances in color display science. So far, most of the work in this field has been focused on achieving static colors, limiting many potential applications. This inevitably calls for the development of dynamic color displays with advanced and innovative functionalities. In this Letter, we demonstrate a novel dynamic color printing scheme using magnesium-based pixelated Fabry-Pérot cavities by gray scale nanolithography. With controlled hydrogenation and dehydrogenation, magnesium undergoes unique metal and dielectric transitions, enabling distinct blank and color states from the pixelated Fabry-Pérot resonators. Following such a scheme, we first demonstrate dynamic Ishihara plates, in which the encrypted images can only be read out using hydrogen as information decoding key. We also demonstrate a new type of dynamic color generation, which enables fascinating transformations between black/white printing and color printing with fine tonal tuning. Our work will find wide-ranging applications in full-color printing and displays, colorimetric sensing, information encryption and anticounterfeiting.

  14. The MEDICI reactor cavity model: Chapter 5

    International Nuclear Information System (INIS)

    Bergeron, K.D.; Trebilcock, W.

    1983-01-01

    The MEDICI reactor cavity model is currently under development with the goal of providing a flexible, relatively realistic treatment of ex-vessel severe accident phenomena suitable for large system codes like CONTAIN and MELCOR. The code is being developed with an emphasis on top-down design, to facilitate adaptability and multiple applications. A brief description of the overall code structure is provided. One of the key new models is then described in more detail. This is a dynamic quench model for debris beds. An example calculation using this model is presented. The question of whether it is necessary to consider the simultaneous motion of the quench front and ablation of the concrete is addressed with some scoping models. It is found that for realistic parameters and coolable beds, concrete ablation is too slow a process to be important on the quenching time scale. Remelt in the dry zone, however, is found to be potentially important on this time scale, so quench and remelt are considered simultaneously

  15. Modeling of Coupled Nano-Cavity Lasers

    DEFF Research Database (Denmark)

    Skovgård, Troels Suhr

    Modeling of nanocavity light emitting semiconductor devices is done using the semiconductor laser rate equations with spontaneous and stimulated emission terms modified for Purcell enhanced recombination. The modified terms include details about the optical and electronic density-of-states and it......Modeling of nanocavity light emitting semiconductor devices is done using the semiconductor laser rate equations with spontaneous and stimulated emission terms modified for Purcell enhanced recombination. The modified terms include details about the optical and electronic density......-of-states relative to the optical density-of-states. The low effective Purcell eect for quantum well devices limits the highest possible modulation bandwidth to a few tens of gigahertz, which is comparable to the performance of conventional diode lasers. Compared to quantum well devices, quantum dot devices have...... is useful for design of coupled systems. A tight-binding description for coupled nanocavity lasers is developed and employed to investigate the phase-locking behavior for the system of two coupled cavities. Phase-locking is found to be critically dependent on exact parameter values and to be dicult...

  16. Gross morphology of rhea oropharyngeal cavity

    Directory of Open Access Journals (Sweden)

    Marcio N. Rodrigues

    2012-12-01

    Full Text Available The rhea (Rhea americana americana is an american bird belonging to Ratite's family. Studies related to its morphology are still scarce. This study aims to describe the macroscopic structures of the oropharyngeal cavity. Five heads (2 to 6 months old formalin preserved were anatomically dissected to expose the oropharynx. The oropharynx of the rhea was "bell-shaped" composed by the maxillary and mandibular rhamphotheca. The roof and floor presented two distinct regions different in colour of the mucosa. The rostral region was pale pink contrasting to grey coloured caudal region. The median longitudinal ridge extended rostrally from the apex of the choana to the tip of the beak in the roof and it is clearly more prominent and rigid than the homolog in the floor that appeared thin and stretched merely along the rostral portion of the regio interramalis. The floor was formed by the interramal region, (regio interramalis tongue and laryngeal mound containing glove-shaped glottis. This study confirmed the basic morphology of the oropharinx of the rhea. However, important morphological information not previously described is highlighted and contradictory information present in the literature is clarified.

  17. Development and application of 3D RF cavity code MAFIA

    International Nuclear Information System (INIS)

    Gao Tieta

    1992-01-01

    The design of a asymmetric RF cavity requires a code that can treat 3D structure. This paper describes the characteristics, functions and applications of the 3D RF cavity computer-aided design (CAD) program MAFIA. The 3D geometry design of non-axial symmetric RF cavity with a coupler is realized by CAD method. A kind of data input is presented that can save not only machine memory, but also the CPU time, and large programs can be run on a medium-small size machine. The numerical simulation of a L-band RF cavity is presented and the modeling results agree well with its experimental values. We have also compared electric properties of the RF cavity with variant geometry by applying 3D numerical and graphic simulations. The influence on electric and magnetic fields by adding a input coupler or HOM coupler at the side of a RF cavity is analysed. Adding a coupler to a RF cavity can cause the change of resonance frequency. A method that can compensate the variation of frequency is also presented

  18. Cavity RF mode analysis using a boundary-integral method

    International Nuclear Information System (INIS)

    Jong, M.S. de; Adams, F.P.

    1993-01-01

    A 3-dimensional boundary-integral method has been developed for rf cavity mode analysis. A frequency-dependent, homogeneous linear matrix equation is generated from a variant of the magnetic field integral equation (MFIE) where the domain of integration is a closed surface specifying the rf envelope of the cavity. Frequencies at which the MFIE has non-zero solutions are mode frequencies of the cavity, and the solutions are the corresponding surface magnetic field distributions. The MFIE can then be used to calculate the electric and magnetic field at any other point inside the cavity. Forward iteration is used to find the largest complex eigenvalue of the matrix at a specific frequency. This eigenvalue is 1 when the frequency corresponds to a cavity rf resonance. The matrix equivalent of the MFIE is produced by approximating the cavity surface by a set of perfectly conducting surface elements, and assuming that the surface magnetic field has constant amplitude on each element. The method can handle cavities with complex symmetries, and be easily integrated with finite-element heat-transfer and stress analysis codes

  19. The use of microperforated plates to attenuate cavity resonances

    DEFF Research Database (Denmark)

    Fenech, Benjamin; Keith, Graeme; Jacobsen, Finn

    2006-01-01

    The use of microperforated plates to introduce damping in a closed cavity is examined. By placing a microperforated plate well inside the cavity instead of near a wall as traditionally done in room acoustics, high attenuation can be obtained for specific acoustic modes, compared with the lower at......'s functions. The results, which are validated experimentally, show that a microperforated plate can provide substantial attenuation of modes in a cavity. One possible application of these findings is the treatment of boiler tones in heat-exchanger cavities.......The use of microperforated plates to introduce damping in a closed cavity is examined. By placing a microperforated plate well inside the cavity instead of near a wall as traditionally done in room acoustics, high attenuation can be obtained for specific acoustic modes, compared with the lower...... attenuation that can be obtained in a broad frequency range with the conventional position of the plate. An analytical method for predicting the attenuation is presented. The method involves finding complex eigenvalues and eigenfunctions for the modified cavity and makes it possible to predict Green...

  20. Surface processing for bulk niobium superconducting radio frequency cavities

    Science.gov (United States)

    Kelly, M. P.; Reid, T.

    2017-04-01

    The majority of niobium cavities for superconducting particle accelerators continue to be fabricated from thin-walled (2-4 mm) polycrystalline niobium sheet and, as a final step, require material removal from the radio frequency (RF) surface in order to achieve performance needed for use as practical accelerator devices. More recently bulk niobium in the form of, single- or large-grain slices cut from an ingot has become a viable alternative for some cavity types. In both cases the so-called damaged layer must be chemically etched or electrochemically polished away. The methods for doing this date back at least four decades, however, vigorous empirical studies on real cavities and more fundamental studies on niobium samples at laboratories worldwide have led to seemingly modest improvements that, when taken together, constitute a substantial advance in the reproducibility for surface processing techniques and overall cavity performance. This article reviews the development of niobium cavity surface processing, and summarizes results of recent studies. We place some emphasis on practical details for real cavity processing systems which are difficult to find in the literature but are, nonetheless, crucial for achieving the good and reproducible cavity performance. New approaches for bulk niobium surface treatment which aim to reduce cost or increase performance, including alternate chemical recipes, barrel polishing and ‘nitrogen doping’ of the RF surface, continue to be pursued and are closely linked to the requirements for surface processing.

  1. Recent Developments in SRF Cavity Science and Performance

    Energy Technology Data Exchange (ETDEWEB)

    G. Ciovati

    2006-08-10

    The performances of SRF cavities made of high purity bulk niobium have been improving in the last few years and surface magnetic fields (Bp) close to the thermodynamic critical field of niobium have been achieved in a few cases. The recommendation made in 2004 in favor of SRF as the technology of choice for the International Linear Collider (ILC), requires improving the reliability of multi-cell cavities operating at accelerating gradients (Eacc) of the order of 35 MV/m. Additionally, a better understanding of the present limitations to cavity performance, such as the high-field Q-drop is needed. This contribution presents some recent developments in SRF cavity science and performance. Among the most significant advances of the last few years, new cavity shapes with lower ratio Bp/Eacc were designed and tested. Cavities made of large-grain niobium became available, promising lower cost at comparable performance to standard fine-grain ones and several tests on single-cell cavities were done to gain a better understanding of high-field losses. In addition, studies to improve the reliability of electropolishing are being carried out by several research groups.

  2. Momentum diffusion for coupled atom-cavity oscillators

    International Nuclear Information System (INIS)

    Murr, K.; Maunz, P.; Pinkse, P. W. H.; Puppe, T.; Schuster, I.; Rempe, G.; Vitali, D.

    2006-01-01

    It is shown that the momentum diffusion of free-space laser cooling has a natural correspondence in optical cavities when the internal state of the atom is treated as a harmonic oscillator. We derive a general expression for the momentum diffusion, which is valid for most configurations of interest: The atom or the cavity or both can be probed by lasers, with or without the presence of traps inducing local atomic frequency shifts. It is shown that, albeit the (possibly strong) coupling between atom and cavity, it is sufficient for deriving the momentum diffusion to consider that the atom couples to a mean cavity field, which gives a first contribution, and that the cavity mode couples to a mean atomic dipole, giving a second contribution. Both contributions have an intuitive form and present a clear symmetry. The total diffusion is the sum of these two contributions plus the diffusion originating from the fluctuations of the forces due to the coupling to the vacuum modes other than the cavity mode (the so-called spontaneous emission term). Examples are given that help to evaluate the heating rates induced by an optical cavity for experiments operating at low atomic saturation. We also point out intriguing situations where the atom is heated although it cannot scatter light

  3. Photodynamic Therapy Using Temoporfin Before Surgery in Treating Patients With Recurrent Oral Cavity or Oropharyngeal Cancer

    Science.gov (United States)

    2014-09-02

    Recurrent Squamous Cell Carcinoma of the Lip and Oral Cavity; Recurrent Squamous Cell Carcinoma of the Oropharynx; Recurrent Verrucous Carcinoma of the Oral Cavity; Stage I Squamous Cell Carcinoma of the Lip and Oral Cavity; Stage I Squamous Cell Carcinoma of the Oropharynx; Stage I Verrucous Carcinoma of the Oral Cavity; Stage II Squamous Cell Carcinoma of the Lip and Oral Cavity; Stage II Squamous Cell Carcinoma of the Oropharynx; Stage II Verrucous Carcinoma of the Oral Cavity; Tongue Cancer

  4. Optical re-injection in cavity-enhanced absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Leen, J. Brian, E-mail: b.leen@lgrinc.com; O’Keefe, Anthony [Los Gatos Research, 67 E. Evelyn Avenue, Suite 3, Mountain View, California 94041 (United States)

    2014-09-15

    Non-mode-matched cavity-enhanced absorption spectrometry (e.g., cavity ringdown spectroscopy and integrated cavity output spectroscopy) is commonly used for the ultrasensitive detection of trace gases. These techniques are attractive for their simplicity and robustness, but their performance may be limited by the reflection of light from the front mirror and the resulting low optical transmission. Although this low transmitted power can sometimes be overcome with higher power lasers and lower noise detectors (e.g., in the near-infrared), many regimes exist where the available light intensity or photodetector sensitivity limits instrument performance (e.g., in the mid-infrared). In this article, we describe a method of repeatedly re-injecting light reflected off the front mirror of the optical cavity to boost the cavity's circulating power and deliver more light to the photodetector and thus increase the signal-to-noise ratio of the absorption measurement. We model and experimentally demonstrate the method's performance using off-axis cavity ringdown spectroscopy (OA-CRDS) with a broadly tunable external cavity quantum cascade laser. The power coupled through the cavity to the detector is increased by a factor of 22.5. The cavity loss is measured with a precision of 2 × 10{sup −10} cm{sup −1}/√(Hz;) an increase of 12 times over the standard off-axis configuration without reinjection and comparable to the best reported sensitivities in the mid-infrared. Finally, the re-injected CRDS system is used to measure the spectrum of several volatile organic compounds, demonstrating the improved ability to resolve weakly absorbing spectroscopic features.

  5. Evaluation of the Helicobacteraceae in the oral cavity of dogs.

    Science.gov (United States)

    Craven, Melanie; Recordati, Camilla; Gualdi, Valentina; Pengo, Graziano; Luini, Mario; Scanziani, Eugenio; Simpson, Kenneth W

    2011-11-01

    To determine the Helicobacter spp present in the oral cavity of dogs and the relationship of those organisms with gastric Helicobacter spp to better define the potential for dog-human and dog-dog transmission. Saliva and dental plaque from 28 dogs and gastric biopsy specimens from a subset of 8 dogs. PCR-based screening for Helicobacter spp was conducted on samples obtained from the oral cavity of 28 dogs. Comparative analysis was conducted on Helicobacteraceae 16S rDNA clone libraries from the oral cavity and stomach of a subset of 8 dogs (5 vomiting and 3 healthy) that had positive PCR results for Helicobacter spp. Helicobacteraceae DNA was identified in the oral cavity of 24 of 28 dogs. Analysis of cloned 16S rDNA amplicons from 8 dogs revealed that Wolinella spp was the most common (8/8 dogs) and abundant (52/57 [91%] clones) member of the Helicobacteraceae family in the oral cavity. Only 2 of 8 dogs harbored Helicobacter spp in the oral cavity, and 1 of those was coinfected with Helicobacter heilmannii and Helicobacter felis in samples obtained from the stomach and saliva. Evaluation of oral cavity DNA with Wolinella-specific PCR primers yielded positive results for 16 of 20 other dogs (24/28 samples were positive for Wolinella spp). Wolinella spp rather than Helicobacter spp were the predominant Helicobacteraceae in the oral cavity of dogs. The oral cavity of dogs was apparently not a zoonotically important reservoir of Helicobacter spp that were non-Helicobacter pylori organisms.

  6. Novel deflecting cavity design for eRHIC

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Q.; Belomestnykh, S.; Ben-Zvi, I.

    2011-07-25

    To prevent significant loss of the luminosity due to large crossing angle in the future ERL based Electron Ion Collider at BNL (eRHIC), there is a demand for crab cavities. In this article, we will present a novel design of the deflecting/crabbing 181 MHz superconducting RF cavity that will fulfil the requirements of eRHIC. The quarter-wave resonator structure of the new cavity possesses many advantages, such as compact size, high R{sub t}/Q, the absence of the same order mode and lower order mode, and easy higher order mode damping. We will present the properties and characteristics of the new cavity in detail. As the accelerator systems grow in complexity, developing compact and efficient deflecting cavities is of great interest. Such cavities will benefit situations where the beam line space is limited. The future linac-ring type electron-ion collider requires implementation of a crab-crossing scheme for both beams at the interaction region. The ion beam has a long bunches and high rigidity. Therefore, it requires a low frequency, large kicking angle deflector. The frequency of the deflecting mode for the current collider design is 181 MHz, and the deflecting angle is {approx}5 mrad for each beam. At such low frequency, the previous designs of the crab cavities will have very large dimensions, and also will be confronted by typical problems of damping the Lower Order Mode (LOM), the Same Order Mode (SOM), and as usual, the Higher Order Modes (HOM). In this paper we describe how one can use the concept of a quarter-wave (QW) resonator for a deflecting/crabbing cavity, and use its fundamental mode to deflect the beam. The simplicity of the cavity geometry and the large separation between its fundamental mode and the first HOM make it very attractive.

  7. CERN physicist receives Einstein Medal

    CERN Multimedia

    2006-01-01

    On 29 June the CERN theorist Gabriele Veneziano was awarded the prestigious Albert Einstein Medal for significant contributions to the understanding of string theory. This award is given by the Albert Einstein Society in Bern to individuals whose scientific contributions relate to the work of Einstein. Former recipients include exceptional physicists such as Murray Gell-Mann last year, but also Stephen Hawking and Victor Weisskopf. Gabriele Veneziano, a member of the integrated CERN Theory Team since 1977, led the Theory Division from 1994 to 1997 and has already received many prestigious prizes for his outstanding work, including the Enrico Fermi Prize (see CERN Courier, November 2005), the Dannie Heineman Prize for mathematical physics of the American Physical Society in 2004 (see Bulletin No. 47/2003), and the I. Ya. Pomeranchuk Prize of the Institute of Theoretical and Experimental Physics (Moscow) in 1999.

  8. On the applicability of conventional transmission line theory within cavities

    Directory of Open Access Journals (Sweden)

    F. Gronwald

    2006-01-01

    Full Text Available We investigate whether or not conventional transmission line theory needs to be modified if transmission lines are considered that are located in a cavity rather than in free space. Our analysis is based on coupled Pocklington's equations that can be reduced to integral equations for the antenna mode and the transmission line mode. Under the usual assumptions of conventional transmission line theory these modes do approximately decouple within a cavity. As a result, cavity properties will primarily influence the antenna mode but not the transmission line mode.

  9. Calculation of mechanical vibration frequencies of stiffened superconducting cavities

    International Nuclear Information System (INIS)

    Black, S.J.; Spalek, G.

    1992-01-01

    We calculated the frequencies of transverse and longitudinal mechanical-vibration modes of the HEPL- modified, CERN/DESY four-cell superconducting cavity, using finite-element techniques. We compared the results of these calculations, including the stiffening of the cavity with rods, with mode frequencies measured at HEPL. The correlation between data was significant. The same techniques were also used to design and optimize the stiffening scheme for the seven-cell 805-MHz superconducting cavity being developed at Los Alamos. In this report, we describe the final stiffening scheme and the results of our calculations

  10. Status of SCRF cavity and ADS development in Japan

    International Nuclear Information System (INIS)

    Yamamoto, Akira

    2011-01-01

    SCRF cavity technology has progressed with high-energy particle accelerator programs in Japan. It was first applied for TRISTAN program at KEK, in early 1980s, and it is expected to be a key technology to realize the next energy-frontier lepton collider such as ILC, and/or intensity-frontier proton accelerators hopefully to be realized in Japan. The JPARC project as a joint program between JAEA and KEK is scoping to realize ADS program with the linac upgrade using a superconducting cavity system, as a future program. The talk will cover an overview of the SCRF cavity development and the ADS development in Japan. (author)

  11. Open waveguide cavity using a negative index medium.

    Science.gov (United States)

    Yan, Wei; Shen, Linfang

    2008-12-01

    An open waveguide cavity formed by a pair of planar waveguides, in which one guiding layer is a negative index medium and the other is a positive index medium, is theoretically demonstrated. For such a waveguide cavity the resonant frequency is independent of the total length of the waveguide system. With the coupled mode theory it is shown that energy flow circulation can be established through the special coupling between the waveguides at the resonant frequency, and thus the wave fields are localized. This phenomenon is further verified numerically with the finite-difference time-domain method. The quality factor of the open waveguide cavity is also discussed.

  12. Squeezing-enhanced measurement sensitivity in a cavity optomechanical system

    DEFF Research Database (Denmark)

    Kerdoncuff, Hugo; Hoff, Ulrich Busk; Harris, Glen I.

    2015-01-01

    We determine the theoretical limits to squeezing-enhanced measurement sensitivity of mechanical motion in a cavity optomechanical system. The motion of a mechanical resonator is transduced onto quadrature fluctuations of a cavity optical field and a measurement is performed on the optical field...... exiting the cavity. We compare measurement sensitivities obtained with coherent probing and quantum-enhanced probing of the mechanical motion, i.e. the coherent probe field carries vacuum states and quadrature squeezed vacuum states at sideband frequencies, respectively. We find that quantum...

  13. Wakefield calculation for superconducting TM110 cavity without azimuthal symmetry

    Energy Technology Data Exchange (ETDEWEB)

    Bellantoni, Leo; /Fermilab; Burt, Graeme; /Lancaster U.

    2006-08-01

    The 3.9GHz TM{sub 110} mode deflecting cavity developed at FNAL has many applications, including use as a longitudinal bunch profile diagnostic, and as a crab cavity candidate for the ILC. These applications involve beams with substantial time structure. For the 13-cell version intended for the bunch profile application, long-range wakes have been evaluated in the frequency domain and short-range wakes have been evaluated in the time domain. Higher-order interactions of the main field in the cavity with the beam have also been parameterized. Pedagogic derivations are included as appendices.

  14. RF-cavity for the X-ray generator NESTOR

    International Nuclear Information System (INIS)

    Androsov, V.P.; Gvozd, A.M.; Karnaukhov, I.M.; Telegin, Yu.N.; Chernov, K.N.; Ostreyko, G.N.; Sedlyarov, I.K.

    2007-01-01

    In the Kharkov Institute of Physics and Technology 225 MeV electron storage ring NESTOR is under development. The paper describes the design and parameters of a 700 MHz cavity that has been fabricated at BINP for the NESTOR RF-system. Now the low-power and vacuum tests of the cavity are under way at BINP. We present here the results of 3D simulations of the cavity with ANSYS code. The problem of multibunch instabilities in NESTOR is also discussed

  15. A fast cavity dumper for a picosecond glass laser

    Science.gov (United States)

    Oak, S. M.; Bindra, K. S.; Narayan, B. S.; Khardekar, R. K.

    1991-02-01

    A fast cavity dumper for picosecond glass laser has been made. The optical and electrical characterization of the cavity dumper is described. An avalanche transistor Marx bank generator drives the cavity dumper. Up to 5 kV peak amplitude and 1.5 ns fall time negative polarity step pulses are generated by the Marx bank circuit. With a capacitive load like Pockels cell the pulse fall time increases to 4 ns. Optical switching times as fast as 2 ns (10%-90%) are experimentally measured. The contrast ratio of 1000 is obtained after a double pass through an amplifier. Single picosecond pulses are produced with an energy jitter of 10%.

  16. First prototype Copper-Niobium RF Superconducting Cavity

    CERN Multimedia

    1983-01-01

    This is the first RF superconducting cavity made of copper with a very thin layer of pure niobium deposited on the inner wall by sputtering. This new developpment lead to a considerable increase of performance and stability of superconducting cavities and to non-negligible economy. The work was carried out in the ISR workshop. This technique was adopted for the LEP II accelerating cavities. At the centre is Cristoforo Benvenuti, inventor of this important technology, with his assistants, Nadia Circelli and Max Hauer, carrying the sputtering electrode. See also 8209255, 8312339.

  17. Study of medium beta elliptical cavities for CADS

    Science.gov (United States)

    Wen, Liangjian; Zhang, Shenghu; Li, Yongming; Wang, Ruoxu; Guo, Hao; Zhang, Cong; Jia, Huan; Jiang, Tiancai; Li, Chunlong; He, Yuan

    2016-02-01

    The China Accelerator-Driven Sub-critical System (CADS) is a high intensity proton facility to dispose of nuclear waste and generate electric power. CADS is based on a 1.5 GeV, 10 mA CW superconducting (SC) linac as a driver. The high energy section of the linac is composed of two families of SC elliptical cavities which are designed with geometrical beta 0.63 and 0.82. In this paper, the 650 MHz β=0.63 SC elliptical cavity is studied, including cavity optimization, multipacting, high order modes (HOMs) and generator RF power calculation. Supported by National Natural Science Foundation of China (91426303)

  18. Double diffusion in arbitrary porous cavity: Part II

    Science.gov (United States)

    Ahamad, N. Ameer; Kamangar, Sarfaraz; Salman Ahmed N., J.; Soudagar, Manzoor Elahi M.; Khan, T. M. Yunus

    2017-07-01

    Heat and mass transfer in porous medium is one of the fundamental topics of interest. The present article is dedicated to study the effect of a small block placed at center of left vertical surface of the cavity. The block is maintained at isothermal temperature That three of its edges attached with porous medium. The left surface of cavity is maintained at highest concentration and right surface at lowest concentration. The right surface of cavity is at cold isothermal temperature Tc. Governing equations are converted into matrix form of equations with the help of finite element method and solved iteratively by using a computer code generated in MATLAB.

  19. Electromagnetic Wave Chaos in Gradient Refractive Index Optical Cavities

    International Nuclear Information System (INIS)

    Wilkinson, P. B.; Fromhold, T. M.; Taylor, R. P.; Micolich, A. P.

    2001-01-01

    Electromagnetic wave chaos is investigated using two-dimensional optical cavities formed in a cylindrical gradient refractive index lens with reflective surfaces. When the planar ends of the lens are cut at an angle to its axis, the geometrical ray paths are chaotic. In this regime, the electromagnetic mode spectrum of the cavity is modulated by both real and ghost periodic ray paths, which also 'scar' the electric field intensity distributions of many modes. When the cavity is coupled to waveguides, the eigenmodes generate complex series of resonant peaks in the electromagnetic transmission spectrum

  20. Heat and mass transfer in porous cavity: Assisting flow

    Energy Technology Data Exchange (ETDEWEB)

    Badruddin, Irfan Anjum [Dept. of Mechanical Engineering, University of Malaya, Kuala Lumpur, 50603 (Malaysia); Quadir, G. A. [School of Mechatronic Engineering, University Malaysia Perlis, Pauh Putra, 02600 Arau, Perlis (Malaysia)

    2016-06-08

    In this paper, investigation of heat and mass transfer in a porous cavity is carried out. The governing partial differential equations are non-dimensionalised and solved using finite element method. The left vertical surface of the cavity is maintained at constant temperature and concentration which are higher than the ambient temperature and concentration applied at right vertical surface. The top and bottom walls of the cavity are adiabatic. Heat transfer is assumed to take place by natural convection and radiation. The investigation is carried out for assisting flow when buoyancy and gravity force act in same direction.