WorldWideScience

Sample records for cavities

  1. Cavities

    Science.gov (United States)

    ... the bacteria produce acids that cause decay. Tooth pain occurs after decay reaches the inside of the tooth. Dentists can detect cavities by examining the teeth and taking x-rays periodically. Good oral hygiene and regular dental care plus a healthy diet can help prevent cavities. ...

  2. Superconducting cavities

    International Nuclear Information System (INIS)

    The basic properties of superconducting cavities for electron accelerators are discussed with special emphasis on the following topics: technical motivation for the use of superconducting cavities; surface impedance; the critical field of superconductors; anomalous losses; materials other than niobium; technological achievements for accelerating cavities. (author)

  3. Dental cavities

    Science.gov (United States)

    ... leading to cavities. Treatment may involve: Fillings Crowns Root canals Dentists fill teeth by removing the decayed tooth ... gold, porcelain, or porcelain attached to metal. A root canal is recommended if the nerve in a tooth ...

  4. 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.

  5. accelerating cavity

    CERN Multimedia

    On the inside of the cavitytThere 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.

  6. Cavity magnomechanics

    Science.gov (United States)

    Zou, Chang-Ling; Zhang, Xufeng; Jiang, Liang; Tang, Hong

    2016-05-01

    Recently, cavity magnonics has attracted much attention for potential applications of coherent information transduction and hybrid quantum devices. The magnon is a collective spin wave excitation in ferromagnetic material. It is magnetically tunability, with long coherence time and non-reciprocical interaction with electro-magnetic fields. We report the coherent coupling between magnon, microwave photon and phonon. First, we demonstrate strong coupling and ultrastrong coupling between the magnon in YIG sphere and microwave photon in three-dimensional cavity. Then, based on the hybridized magnon-photon modes, we observe the triply resonant magnon-mcirowave photon-phonon coupling, where the ultrahigh-Q mechanical vibration of YIG sphere is dispersively coupled with the magnon via magnetostrictive interaction. We observe interesting phenomena, including electromagnetically induced transparency/absorption and parametric amplification. In particular, benefit from the large tunability of the magnon, we demonstrate a tunable microwave amplifier with gain as high as 30 dB. The single crystal YIG also has excellent optical properties, and thus provide a unique platform bridging MHz, GHz and THz information carriers. Finally, we present the latest progress towards coherent magnon to optical photon conversion.

  7. Cavity magnomechanics

    Science.gov (United States)

    Zhang, Xufeng; Zou, Changling; Jiang, Liang; Tang, Hong X.

    Mechanical oscillators have been recently widely utilized to couple with optical and microwave photons in a variety of hybrid quantum systems, but they all lack the tunability. The magnetostrictive force provides an alternative mechanism to allow phonon to couple with a different type of information carrier-magnon, the collective excitation of magnetization whose frequency can be tuned by a bias magnetic field. Here, we demonstrate an intriguing hybrid system that consists of a magnonic, a mechanical, and a microwave resonator. The magnon-phonon interaction results in hallmark coherent phenomena such as magnomechanically induced transparency/absorption and magnomechanical parametric amplification. The magnetic field dependence of magnon provides our system with unprecedented tunability. Moreover, the great flexibility of our system allows us to achieve triple resonance among magnon, phonon and photon, which drastically enhances the magnomechanical interaction. Our work demonstrates the fundamental principle of cavity magnetomechanics, opening up great opportunities in various applications, such as tunable microwave filter and amplifier, long-lifetime quantum memories, microwave-to-optics conversion.

  8. Crab Cavity Development

    CERN Document Server

    Calaga, R; Burt, G; Ratti, A

    2015-01-01

    The HL-LHC upgrade will use deflecting (or crab) cavities to compensate for geometric luminosity loss at low β* and non-zero crossing angle. A local scheme with crab cavity pairs across the IPs is used employing compact crab cavities at 400 MHz. Design of the cavities, the cryomodules and the RF system is well advanced. The LHC crab cavities will be validated initially with proton beam in the SPS.

  9. Superconducting crab cavity

    International Nuclear Information System (INIS)

    Complete overlapping of the electron and positron bunches at colliding point can be attained by using the strong time-depending electromagnetic RF field in the superconducting crab cavity. Commissioning of the crab cavities started in February 2007 at KEKB. Effective head-on collision of electron and positron has been achieved successfully. After introduction of crab crossing and crab cavity, the structure and the fabrication of the KEKB superconducting crab cavity are discussed. (author)

  10. RF Cavity Design

    CERN Document Server

    Jensen, E

    2014-01-01

    After a short overview of a general approach to cavity design, we sketch the derivation of waveguide modes from plane waves and of cavity fields from waveguide modes. The characteristic parameters describing cavities and their performance are defined and explained. An equivalent circuit is introduced and extended to explain beam loading and higher order modes. Finally travelling- and standing-wave multi-gap cavities are introduced using the Brillouin diagram.

  11. Beam cavity interaction

    CERN Document Server

    Gamp, A

    2011-01-01

    We begin by giving a description of the rf generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, rf feedback, and feed-forward are described. Examples of digital rf phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  12. Cavity turnover and equilibrium cavity densities in a cottonwood bottomland

    Science.gov (United States)

    Sedgwick, James A.; Knopf, Fritz L.

    1992-01-01

    A fundamental factor regulating the numbers of secondary cavity nesting (SCN) birds is the number of extant cavities available for nesting. The number of available cavities may be thought of as being in an approximate equilibrium maintained by a very rough balance between recruitment and loss of cavities. Based on estimates of cavity recruitment and loss, we ascertained equilibrium cavity densities in a mature plains cottonwood (Populus sargentii) bottomland along the South Platte River in northeastern Colorado. Annual cavity recruitment, derived from density estimates of primary cavity nesting (PCN) birds and cavity excavation rates, was estimated to be 71-86 new cavities excavated/100 ha. Of 180 active cavities of 11 species of cavity-nesting birds found in 1985 and 1986, 83 were no longer usable by 1990, giving an average instantaneous rate of cavity loss of r = -0.230. From these values of cavity recruitment and cavity loss, equilibrium cavity density along the South Platte is 238-289 cavities/100 ha. This range of equilibrium cavity density is only slightly above the minimum of 205 cavities/100 ha required by SCN's and suggests that cavity availability may be limiting SCN densities along the South Platte River. We submit that snag management alone does not adequately address SCN habitat needs, and that cavity management, expressed in terms of cavity turnover and cavity densities, may be more useful.

  13. Electromagnetic SCRF Cavity Tuner

    Energy Technology Data Exchange (ETDEWEB)

    Kashikhin, V.; Borissov, E.; Foster, G.W.; Makulski, A.; Pischalnikov, Y.; Khabiboulline, T.; /Fermilab

    2009-05-01

    A novel prototype of SCRF cavity tuner is being designed and tested at Fermilab. This is a superconducting C-type iron dominated magnet having a 10 mm gap, axial symmetry, and a 1 Tesla field. Inside the gap is mounted a superconducting coil capable of moving {+-} 1 mm and producing a longitudinal force up to {+-} 1.5 kN. The static force applied to the RF cavity flanges provides a long-term cavity geometry tuning to a nominal frequency. The same coil powered by fast AC current pulse delivers mechanical perturbation for fast cavity tuning. This fast mechanical perturbation could be used to compensate a dynamic RF cavity detuning caused by cavity Lorentz forces and microphonics. A special configuration of magnet system was designed and tested.

  14. Superconducting cavity development

    International Nuclear Information System (INIS)

    Design and development work of the superconducting cavities for the Neutron Science Project is being continued since 1995. In the cavity design work, RF and structural analyses were carried out in order to determine the cavity shape and to obtain the RF and structural parameters. In the cavity development work, preparation of the test facility, fabrication and tests of the two single-cell prototype cavities of β=0.5 were performed. Good performance of the cavity was demonstrated in the test; obtained surface peak electric field of 44 MV/m is much higher than the design value of 16 MV/m. Resonant frequency shifts due to the vacuum load and the Lorentz force were also measured in the test. (author)

  15. 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.

  16. Optically measuring interior cavities

    Science.gov (United States)

    Stone, Gary Franklin

    2009-11-03

    A method of measuring the three-dimensional volume or perimeter shape of an interior cavity includes the steps of collecting a first optical slice of data that represents a partial volume or perimeter shape of the interior cavity, collecting additional optical slices of data that represents a partial volume or perimeter shape of the interior cavity, and combining the first optical slice of data and the additional optical slices of data to calculate of the three-dimensional volume or perimeter shape of the interior cavity.

  17. SPS accelerating cavity

    CERN Multimedia

    CERN PhotoLab

    1981-01-01

    One of the SPS accelerating cavities (200 MHz, travelling wave structure). The power that is fed into the upstream end of the cavity is extracted at the downstream end and sent into a dump load. See 7603195 for more details, 7411032 for the travelling wave structure, and also 8011289, 8302397.

  18. SPS accelerating cavity

    CERN Multimedia

    1980-01-01

    One of the SPS acceleration cavities (200 MHz, travelling wave structure). On the ceiling one sees the coaxial transmission line which feeds the power from the amplifier, located in a surface building above, to the upstream end of the cavity. See 7603195 for more details, 7411032 for the travelling wave structure, and also 8104138, 8302397.

  19. Superconducting RF cavities

    CERN Document Server

    Bernard, Philippe

    1999-01-01

    It was 20 years ago when the research and development programme for LEP superconducting cavities was initiated. It lasted about 10 years. Today, my aim is not to tell you in great detail about the many innovations made thanks to our research, but I would like to point out some milestones in the development of superconducting cavities where Emilio's influence was particularly important.

  20. Ferrite loaded rf cavity

    International Nuclear Information System (INIS)

    The mechanism of a ferrite-loaded rf cavity is explained from the point of view of its operation. Then, an analysis of the automatic cavity-tuning system is presented using the transfer function; and a systematic analysis of a beam-feedback system using transfer functions is also presented. (author)

  1. Superconducting cavities for LEP

    CERN Multimedia

    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. Passivated niobium cavities

    Science.gov (United States)

    Myneni, Ganapati Rao; Hjorvarsson, Bjorgvin; Ciovati, Gianluigi

    2006-12-19

    A niobium cavity exhibiting high quality factors at high gradients is provided by treating a niobium cavity through a process comprising: 1) removing surface oxides by plasma etching or a similar process; 2) removing hydrogen or other gases absorbed in the bulk niobium by high temperature treatment of the cavity under ultra high vacuum to achieve hydrogen outgassing; and 3) assuring the long term chemical stability of the niobium cavity by applying a passivating layer of a superconducting material having a superconducting transition temperature higher than niobium thereby reducing losses from electron (cooper pair) scattering in the near surface region of the interior of the niobium cavity. According to a preferred embodiment, the passivating layer comprises niobium nitride (NbN) applied by reactive sputtering.

  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. 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.

  5. Hydroforming of elliptical cavities

    Science.gov (United States)

    Singer, W.; Singer, X.; Jelezov, I.; Kneisel, P.

    2015-02-01

    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 Eacc 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 Eacc of 30 - 35 MV /m were measured after BCP and Eacc 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 Eacc=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 double-cell cavities of the TESLA shape have been

  6. 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

  7. SPS RF cavity

    CERN Multimedia

    1974-01-01

    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. A power of up to 790 kW can be supplied to each giving a total accelerating voltage of about 8 MV. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities.

  8. SPS accelerating cavity

    CERN Multimedia

    1983-01-01

    See photo 8202397: View towards the downstream end of one of the SPS accelerating cavities (200 MHz, travelling wave structure). See 7603195 and 8011289 for more details, 7411032 for the travelling wave structure, and also 8104138.

  9. SPS accelerating cavity

    CERN Multimedia

    1983-01-01

    View towards the downstream end of one of the SPS accelerating cavities (200 MHz, travelling wave structure). See 7603195 and 8011289 for more details, 7411032 for the travelling wave structure, and also 8104138.

  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. Moving Detectors in Cavities

    CERN Document Server

    Obadia, N

    2007-01-01

    We consider two-level detectors, coupled to a quantum scalar field, moving inside cavities. We highlight some pathological resonant effects due to abrupt boundaries, and decide to describe the cavity by switching smoothly the interaction by a time-dependent gate-like function. Considering uniformly accelerated trajectories, we show that some specific choices of non-adiabatic switching have led to hazardous interpretations about the enhancement of the Unruh effect in cavities. More specifically, we show that the emission/absorption ratio takes arbitrary high values according to the emitted quanta properties and to the transients undergone at the entrance and the exit of the cavity, {\\it independently of the acceleration}. An explicit example is provided where we show that inertial and uniformly accelerated world-lines can even lead to the same ``pseudo-temperature''.

  12. SPS accelerating cavity

    CERN Multimedia

    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.

  13. Melatonin and Oral Cavity

    OpenAIRE

    Murat İnanç Cengiz; Seda Cengiz; Hom-Lay Wang

    2012-01-01

    While initially the oral cavity was considered to be mainly a source of various bacteria, their toxins and antigens, recent studies showed that it may also be a location of oxidative stress and periodontal inflammation. Accordingly, this paper focuses on the involvement of melatonin in oxidative stress diseases of oral cavity as well as on potential therapeutic implications of melatonin in dental disorders. Melatonin has immunomodulatory and antioxidant activities, stimulates the proliferatio...

  14. Oral cavity and leprosy

    OpenAIRE

    Shambulingappa Pallagatti; Soheyl Sheikh; Anupreet Kaur; Amit Aggarwal; Ravinder Singh2

    2012-01-01

    Although leprosy involves the oral cavity in up to 60% of the patients, examination of the oral cavity in leprosy clinics or oral health science clinics is often neglected. Oral involvement in leprosy can broadly be divided into non-specific and specific lesions. In this review, we discuss various oral manifestations in leprosy patients so as to increase the awareness about this aspect among dermatologists and dental surgeons.

  15. Hydroforming of Elliptical Cavities

    OpenAIRE

    W. Singer; Singer, X.; Jelezov, I.; Kneisel, P.

    2015-01-01

    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 ...

  16. 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....

  17. Metasurface external cavity laser

    Science.gov (United States)

    Xu, Luyao; Curwen, Christopher A.; Hon, Philip W. C.; Chen, Qi-Sheng; Itoh, Tatsuo; Williams, Benjamin S.

    2015-11-01

    A vertical-external-cavity surface-emitting-laser is demonstrated in the terahertz range, which is based upon an amplifying metasurface reflector composed of a sub-wavelength array of antenna-coupled quantum-cascade sub-cavities. Lasing is possible when the metasurface reflector is placed into a low-loss external cavity such that the external cavity—not the sub-cavities—determines the beam properties. A near-Gaussian beam of 4.3° × 5.1° divergence is observed and an output power level >5 mW is achieved. The polarized response of the metasurface allows the use of a wire-grid polarizer as an output coupler that is continuously tunable.

  18. Metasurface external cavity laser

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Luyao, E-mail: luyaoxu.ee@ucla.edu; Curwen, Christopher A.; Williams, Benjamin S. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); California NanoSystems Institute, University of California, Los Angeles, California 90095 (United States); Hon, Philip W. C.; Itoh, Tatsuo [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Chen, Qi-Sheng [Northrop Grumman Aerospace Systems, Redondo Beach, California 90278 (United States)

    2015-11-30

    A vertical-external-cavity surface-emitting-laser is demonstrated in the terahertz range, which is based upon an amplifying metasurface reflector composed of a sub-wavelength array of antenna-coupled quantum-cascade sub-cavities. Lasing is possible when the metasurface reflector is placed into a low-loss external cavity such that the external cavity—not the sub-cavities—determines the beam properties. A near-Gaussian beam of 4.3° × 5.1° divergence is observed and an output power level >5 mW is achieved. The polarized response of the metasurface allows the use of a wire-grid polarizer as an output coupler that is continuously tunable.

  19. 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.

  20. SPS accelerating cavity

    CERN Multimedia

    1983-01-01

    See photo 8302397: View from the downstream end of one of the SPS accelerating cavities (200 MHz, travelling wave structure). See 7603195 and 8011289 for more details, 7411032 for the travelling wave structure, and also 8104138. Giacomo Primadei stands on the left.

  1. Laser cavity modelling

    OpenAIRE

    Damakoa, I.; Audounet, J.; Bouyssou, G.; Vassilieff, G.

    1993-01-01

    Two approachs of modelling nonhomogeneous cavity laser are presented. They are based on the beam propagation method which allows the use of fast Fourier transform (FFT). The resulting procedures provide selfconsistent solutions to the Maxwell and diffusion equations. Results are given to illustrate the two methods.


  2. 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.

  3. Cavity launchers for ICRF

    International Nuclear Information System (INIS)

    A type of resonant coil cavity is analyzed as a launcher for ICRF. This approach offers the advantages of: (1) convenient and flexible sizing, (2) ease of operation and maintenance, and (3) high power handling capability. We present results for resonance conditions, mode structures, power handling capabilities, and sensitivity to variation in plasma parameters

  4. Statistical electromagnetics: Complex cavities

    NARCIS (Netherlands)

    Naus, H.W.L.

    2008-01-01

    A selection of the literature on the statistical description of electromagnetic fields and complex cavities is concisely reviewed. Some essential concepts, for example, the application of the central limit theorem and the maximum entropy principle, are scrutinized. Implicit assumptions, biased choic

  5. 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 ...

  6. Niobium superconducting cavity

    CERN Multimedia

    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.

  7. Implosion of the small cavity and large cavity cannonball targets

    International Nuclear Information System (INIS)

    Recent results of cannonball target implosion research are briefly reviewed with theoretical predictions for GEKKO XII experiments. The cannonball targets are classified into two types according to the cavity size ; small cavity and large cavity. The compression mechanisms of the two types are discussed. (author)

  8. Seamless/bonded niobium cavities

    Science.gov (United States)

    Singer, W.

    2006-07-01

    Technological aspects and performance of seamless cavities produced by hydroforming are presented. Problems related to the fabrication of seamless cavities from bulk niobium are mainly solved thanks to the progress of the last years. The highest achieved accelerating gradients are comparable for both seamless and welded versions (ca. 40 MV/m) Nevertheless further development of seamless cavities is desirable in order to avoid the careful preparation of parts for welding and get reliable statistic. Fabrication of NbCu clad cavities from bimetallic tubes is an interesting option that gives new opportunity to the seamless technique. On the one hand it allows reducing the niobium costs contribution; on the other hand it increases the thermal stability of the cavity. The highest accelerating gradient achieved on seamless NbCu clad single cell cavities (ca. 40 MV/m) is comparable to the one reached on bulk Nb cavities. Fabrication of multi-cell NbCu cavities by hydroforming was recently proven.

  9. Changeability of Oral Cavity Environment

    OpenAIRE

    Surdacka, Anna; Strzyka³a, 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...

  10. 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.

  11. 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.  

  12. RF superconducting cavities

    CERN Document Server

    Kojima, Y

    1980-01-01

    The history and present activity in research on RF superconducting cavities in various countries are reviewed. The program of the July 1980 Karlsruhe workshop is reproduced and research activity in this field at Stanford HEPL and SLAC, Cornell, Oregon, Brookhaven, KEK (Japan), Weismann (Israel), Genoa, CERN and Karlsruhe (KfK) listed. The theoretical basis of surface resistance and intracavity magnetic field, multipacing and non-resonant electron loading are outlined. (20 refs).

  13. Entangling atoms in bad cavities

    OpenAIRE

    Sorensen, Anders S.; Molmer, Klaus

    2002-01-01

    We propose a method to produce entangled spin squeezed states of a large number of atoms inside an optical cavity. By illuminating the atoms with bichromatic light, the coupling to the cavity induces pairwise exchange of excitations which entangles the atoms. Unlike most proposals for entangling atoms by cavity QED, our proposal does not require the strong coupling regime g^2/\\kappa\\Gamma>> 1, where g is the atom cavity coupling strength, \\kappa is the cavity decay rate, and \\Gamma is the dec...

  14. Cavity Backed Slot Antenna

    Directory of Open Access Journals (Sweden)

    Sarang Masani, Ila Parmar, Hitendra Jadeja

    2013-05-01

    Full Text Available Among the current driving forces in wireless communications, there is a need for compact, efficient, inexpensive and reproducible antennas. In some instances, particularly long-distance applications, radiators with directive, high-gain characteristics are necessary. This paper proposes a cavity-backed slot antenna to that end. This antenna will enhance the gain, directivity and can also be easily flush mounted to the flying object. The shape and size of the slot can be effectively utilized to get the desired result. The proposed antenna is feed by waveguide which facilitate it to be applicable at high power operation where coaxial cable fails due to skin effect. Present antenna is verified using Numerical Technique called Finite Element Method FEM. The conception of this antenna is realized by the software HFSS “Ansoft-High Frequency Structure Simulator”. By properly selecting shapes, dimensions of the slots and number of slot affects the parameters like return loss, gain along Θ, Ø directions, Cartesian plot and radiation pattern .The Backing of cavity to the slot antenna provide the basics of the gain enhancement and the slot loading effect and the cavity volume plays an important role in achieving the desired return loss at the specific frequency.The simulated antenna shows the 7.0944 db of gain and return loss of -28.60. The proposed antenna works at 6 GHz.

  15. Crab Cavities for Linear Colliders

    International Nuclear Information System (INIS)

    Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favour a 3.9 GHz superconducting, multi-cell cavity as the solution for ILC, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are fundamental issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders.

  16. Crab Cavities for Linear Colliders

    Energy Technology Data Exchange (ETDEWEB)

    Burt, G.; Ambattu, P.; Carter, R.; Dexter, A.; Tahir, I.; /Cockcroft Inst. Accel. Sci. Tech. /Lancaster U.; Beard, C.; Dykes, M.; Goudket, P.; Kalinin, A.; Ma, L.; McIntosh, P.; /Daresbury; Shulte, D.; /CERN; Jones, Roger M.; /Cockcroft Inst. Accel. Sci. Tech. /Manchester U.; Bellantoni, L.; Chase, B.; Church, M.; Khabouline, T.; Latina, A.; /Fermilab; Adolphsen, C.; Li, Z.; Seryi, Andrei; /SLAC

    2011-11-08

    Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favour a 3.9 GHz superconducting, multi-cell cavity as the solution for ILC, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are fundamental issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders.

  17. Crab cavities for linear colliders

    CERN Document Server

    Burt, G; Carter, R; Dexter, A; Tahir, I; Beard, C; Dykes, M; Goudket, P; Kalinin, A; Ma, L; McIntosh, P; Shulte, D; Jones, Roger M; Bellantoni, L; Chase, B; Church, M; Khabouline, T; Latina, A; Adolphsen, C; Li, Z; Seryi, Andrei; Xiao, L

    2008-01-01

    Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favour a 3.9 GHz superconducting, multi-cell cavity as the solution for ILC, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are fundamental issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders.

  18. 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.

  19. Frequency control of radiofrequency cavity

    OpenAIRE

    Menart, Jure

    2014-01-01

    This work describes the design, development and application of the system for frequency control of EMMA accelerator radiofrequency cavity. The problem with the radiofrequency cavities is, that because of various factors (change in the environmental temperature, mechanical stress, ...), they are continuously frequency detuning. The consequence of the frequency detuning is that electromagnetic field in the cavity is not optimal for the acceleration of the particles. For this reason the resonant...

  20. Single ion cavity QED experiments

    International Nuclear Information System (INIS)

    Full text: We have set up a spherical Paul trap for a storing a single Ca+ ion placed in the center of a high finesse near confocal resonator. We report on experiments demonstrating the coupling of the narrow S1/2-D5/2 transition to the cavity internal light field. Due to the coupling, the ion acts as sensitive probe for the cavity internal field. We are able to map the field distribution by measuring the excitation probability. Scanning the cavity over the resonance imprints a Doppler frequency shift on the cavity field which leads to a spectral shift and a asymmetric broadening of the S-D transition. (author)

  1. Cavity coalescence in superplastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Stowell, M.J.; Livesey, D.W.; Ridley, N.

    1984-01-01

    An analysis of the probability distribution function of particles randomly dispersed in a solid has been applied to cavitation during superplastic deformation and a method of predicting cavity coalescence developed. Cavity size distribution data were obtained from two microduplex nickel-silver alloys deformed superplastically to various extents at elevated temperature, and compared to theoretical predictions. Excellent agreement occurred for small void sizes but the model underestimated the number of voids in the largest size groups. It is argued that the discrepancy results from a combination of effects due to non-random cavity distributions and to enhanced growth rates and incomplete spheroidization of the largest cavities.

  2. Surface state photonic bandgap cavities

    OpenAIRE

    Rahachou, A. I.; Zozoulenko, I. V.

    2005-01-01

    We propose and analyze a new type of a resonant high-Q cavity for lasing, sensing or filtering applications, which is based on a surface states of a finite photonic crystal. We demonstrate that such the cavity can have a Q factor comparable with that one of conventional photonic band-gap defect mode cavities. At the same time, the distinguished feature of the surface mode cavity is that it is situated directly at the surface of the photonic crystal. This might open up new possibilities for de...

  3. Nanofriction in Cavity Quantum Electrodynamics.

    Science.gov (United States)

    Fogarty, T; Cormick, C; Landa, H; Stojanović, Vladimir M; Demler, E; Morigi, Giovanna

    2015-12-01

    The dynamics of cold trapped ions in a high-finesse resonator results from the interplay between the long-range Coulomb repulsion and the cavity-induced interactions. The latter are due to multiple scatterings of laser photons inside the cavity and become relevant when the laser pump is sufficiently strong to overcome photon decay. We study the stationary states of ions coupled with a mode of a standing-wave cavity as a function of the cavity and laser parameters, when the typical length scales of the two self-organizing processes, Coulomb crystallization and photon-mediated interactions, are incommensurate. The dynamics are frustrated and in specific limiting cases can be cast in terms of the Frenkel-Kontorova model, which reproduces features of friction in one dimension. We numerically recover the sliding and pinned phases. For strong cavity nonlinearities, they are in general separated by bistable regions where superlubric and stick-slip dynamics coexist. The cavity, moreover, acts as a thermal reservoir and can cool the chain vibrations to temperatures controlled by the cavity parameters and by the ions' phase. These features are imprinted in the radiation emitted by the cavity, which is readily measurable in state-of-the-art setups of cavity quantum electrodynamics. PMID:26684118

  4. Two-cavity gyroklystron with self-excited input cavity

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, E.V.; Zasypkin, E.V. [Inst. of Applied Physics, Novgorod (Russian Federation)

    1995-12-31

    A new type of gyro-oscillator-two cavity gyroklystron with self-excited input cavity (or, for simplicity, two-cavity gyrokylstron oscillator) is proposed. In this device, the autooscillations excited in the first cavity modulate electrons by energy, electrons are bunched in the drift space, and then the bunches excite powerful oscillations in the second (output) cavity. Since, as in gyroklystron, the optimal second cavity length L{sub 2} does not exceed 2-2.5 {lambda} ({lambda} is the operating wavelength), its Q-factor Q{sub 2} {approximately} (L{sub 2}/{lambda}){sup 2} should be essentially lower than cavity Q-factor of a traditional gyrotron. It allows to diminish the RF ohmic losses in the second cavity and to enhance the output power without the efficiency reduction. A simplest theory of such oscillator has been developed. Predicted by theory, the output power enhancement (in comparison with that for an ordinary gyrotron) has been demonstrated experimentally.

  5. Frequency Tuning for a DQW Crab Cavity

    CERN Document Server

    Verdú-Andrés, Silvia; Ben-Zvi, Ilan; Calaga, Rama; Capatina, Ofelia; Leuxe, Raphael; Skaritka, John; Wu, Qiong; Xiao, Binping; Zanoni, Carlo

    2016-01-01

    The nominal operating frequency for the HL-LHC crab cavities is 400.79 MHz within a bandwidth of ±60kHz. Attaining the required cavity tune implies a good understanding of all the processes that influence the cavity frequency from the moment when the cavity parts are being fabricated until the cavity is installed and under operation. Different tuning options will be available for the DQW crab cavity of LHC. This paper details the different steps in the cavity fabrication and preparation that may introduce a shift in the cavity frequency and introduces the different tuning methods foreseen to bring the cavity frequency to meet the specifications.

  6. A Scanning Cavity Microscope

    CERN Document Server

    Mader, Matthias; Hänsch, Theodor W; Hunger, David

    2014-01-01

    Imaging of the optical properties of individual nanosystems beyond fluorescence can provide a wealth of information. However, the minute signals for absorption and dispersion are challenging to observe, and only specialized techniques requiring sophisticated noise rejection are available. Here we use signal enhancement in a scanning optical microcavity to demonstrate ultra-sensitive imaging. Harnessing multiple interactions of probe light with a sample within an optical resonator, we achieve a 1700-fold signal enhancement compared to diffraction-limited microscopy. We demonstrate quantitative imaging of the extinction cross section of gold nanoparticles with a sensitivity below 1 nm2, we show a method to improve spatial resolution potentially below the diffraction limit by using higher order cavity modes, and we present measurements of the birefringence and extinction contrast of gold nanorods. The demonstrated simultaneous enhancement of absorptive and dispersive signals promises intriguing potential for opt...

  7. Superconducting cavity model for LEP

    CERN Multimedia

    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.

  8. Fiber cavities for atom chips

    OpenAIRE

    Klappauf, B.G.; Horak, P.; Kazansky, P. G.

    2003-01-01

    We present experimental realizations of several micro-cavities, constructed from standard fiber optic components, which meet the theoretical criteria for single atom detection from laser-cooled samples. We discuss integration of these cavities into state-of-the-art 'atom chips'.

  9. Design of a cavity filter

    International Nuclear Information System (INIS)

    A cavity filter was developed for the SSRF 0-mode beam feedback. The filter is used to pick up the 500 MHz signal from the storage ring beam. The Superfish was used to simulate the model of the cavity bandpass filter. The design method, parameters of the filter and results of beam measurements are described in this paper. (authors)

  10. Study on superconducting accelerating cavities

    International Nuclear Information System (INIS)

    A test cavity of cylindrical shape has been designed and constructed to study superconducting accelerating cavities for TRISTAN e+e- Ring. Higher order modes have been calculated by using SUPERFISH program and an analytical method, and measured. The measured resonant frequencies well agree with the calculated results. (author)

  11. Technical tasks in superconducting cavities

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Kenji [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

    1997-11-01

    The feature of superconducting rf cavities is an extremely small surface resistance on the wall. It brings a large energy saving in the operation, even those are cooled with liquid helium. That also makes possible to operate themselves in a higher field gradient comparing to normal conducting cavities, and brings to make accelerators compact. These merits are very important for the future accelerator engineering which is planed at JAERI for the neutron material science and nuclear waste transmutation. This machine is a high intensity proton linac and uses sc cavities in the medium and high {beta} sections. In this paper, starting R and D of proton superconducting cavities, several important technical points which come from the small surface resistance of sc cavities, are present to succeed it and also differences between the medium and high - {beta} structures are discussed. (author)

  12. 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.

  13. 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.

  14. Cavity beam position monitors

    International Nuclear Information System (INIS)

    Beam-based alignment and feedback systems are essential for the operation of future linear colliders and free electron lasers. A certain number of beam position monitors with a resolution in the submicron range are needed at selected locations. Most beam position monitors detect the electric or the magnetic field excited by a beam of charged particles at different locations around the beam pipe. In resonant monitors, however, the excitation of special field configurations by an off-center beam is detected. These structures offer a large signal per micron displacement. This paper is an attempt to summarize the fundamental characteristics of resonant monitors, their advantages and shortcomings. Emphasis will be on the design of cylindrical cavities, in particular on the estimation of expected signals, of resolution limits and the resulting beam distortion. This includes also a short introduction into numerical methods. Fabrication, tuning, and other practical problems will be reviewed briefly. Finally, some resonant devices used for beam position diagnostics will be discussed and listed

  15. Three-dimensional cavity calculations

    International Nuclear Information System (INIS)

    The existence of a code that solves for the resonant electromagnetic modes of oscillation in arbitrarily-shaped three-dimensional cavities opens new possibilities in rf-structure analysis and research. The URMEL-3D code, the product of a multi-year collaboration between DESY, KFA-Juelich, and Los Alamos, has been used in some exploratory studies to determine the feasibility of using a 3-D code to calculate the properties of several practical rf structures. The results are reported here for three cases: the jungle gym, two coupled cavities, and a waveguide-cavity coupling problem

  16. Beam - cavity interaction beam loading

    International Nuclear Information System (INIS)

    The interaction of a beam with a cavity and a generator in cyclic accelerators or storage rings is investigated. Application of Maxwell's equations together with the nonuniform boundary condition allows one to get an equivalent circuit for a beam-loaded cavity. The general equation for beam loading is obtained on the basis of the equivalent circuit, and the beam admittance is calculated. Formulas for power consumption by a beam-loaded cavity are derived, and the optimal tuning and coupling factor are analyzed. (author)

  17. Transferring a cavity field entangled state in cavity QED

    Energy Technology Data Exchange (ETDEWEB)

    Ye Liu [Anhui Key Laboratory of Information Material and Devices, School of Physics and Material Science, Anhui University, Hefei 230039 (China); Guo Guangcan [Key Laboratory of Quantum Information, University of Science and Technology of China, Chinese Academy of Sciences, Hefei 230026 (China)

    2005-08-01

    We propose a scheme for transferring an entanglement of zero- and one-photon states from one cavity to another. The scheme, which has 100% success probability, is mainly based on a two-mode cavity dispersively interacting with a three-level atom in the {lambda} configuration and does not involve Bell-state measurement. This scheme can also be used to teleport an unknown atomic state.

  18. SRF Cavity Fabrication and Materials

    CERN Document Server

    Singer, W

    2014-01-01

    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...

  19. 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.

  20. Geometry-Invariant Resonant Cavities

    CERN Document Server

    Liberal, Iñigo; Engheta, Nader

    2015-01-01

    Resonant cavities are one of the basic building blocks in various disciplines of science and technology, with numerous applications ranging from abstract theoretical modeling to everyday life devices. The eigenfrequencies of conventional cavities are a function of its geometry, and, thus, the size and shape of a resonant cavity is selected in order to operate at a specific frequency. Here, we demonstrate theoretically the existence of geometry-invariant resonant cavities, i.e., resonators whose eigenfrequency is invariant with respect to geometrical deformations. This effect is obtained by exploiting the unusual properties of zero-index metamaterials, which enable decoupling of the time and spatial field variations. This new class of resonators may inspire alternative design concepts, and it might lead to the first generation of deformable resonant devices.

  1. CRAB Cavity in CERN SPS

    International Nuclear Information System (INIS)

    Beam collisions with a crossing angle at the interaction point are often necessary in colliders to reduce the effects of parasitic collisions which induce emittance growth and decrease beam lifetime. The crossing angle reduces the geometrical overlap of the beams and hence the luminosity. Crab cavity offer a promising way to compensate the crossing angle and to realize effective head-on collisions. Moreover, the crab crossing mitigates the synchro-betatron resonances due to the crossing angle. A crab cavity experiment in SPS is proposed as a proof of principle before deciding on a full crab-cavity implementation in the LHC. In this paper, we investigate the effects of a single crab cavity on beam dynamics in the SPS and life time.

  2. LEP Radio Frequency Copper Cavities

    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.

  3. Single and Coupled Nanobeam Cavities

    DEFF Research Database (Denmark)

    Ivinskaya, Aliaksandra; Lavrinenko, Andrei; Shyroki, Dzmitry M.; A. Sukhorukov, Andrey

    This book collects chapters on different theoretical and experimental aspects of photonics crystals for Nanophotonics applications. It is divided in two parts - a theoretical section and an experimental and applicative section. The first part includes chapters developing several numerical methods...... for analysis and design of photonic crystal devices, such as 2D ring resonators for filters, single and coupled nanobeam cavities, birefringence in photonic crystal cavities, threshold analysis in photonic crystal lasers, gap solitons in photonic crystals, novel photonic atolls, dynamic...

  4. RRR Characteristics for SRF Cavities

    OpenAIRE

    Jung, Yoochul; Hyun, Myungook; Joung, Mijoung

    2015-01-01

    The first heavy ion accelerator is being constructed by the rare isotope science project (RISP) launched by the Institute of Basic Science (IBS) in South Korea. Four different types of superconducting cavities were designed, and prototypes were fabricated such as a quarter wave resonator (QWR), a half wave resonator (HWR) and a single spoke resonator (SSR). One of the critical factors determining performances of the superconducting cavities is a residual resistance ratio (RRR). The RRR values...

  5. TEM observations of crack tip: cavity interactions

    International Nuclear Information System (INIS)

    Crack tip-cavity interactions have been studied by performing room temperature deformation experiments in a transmission electron microscope on ion-irradiated type 316 stainless steel with small helium containing cavities. Slip dislocations emitted from a crack tip cut, sheared, and thereby elongated cavities without a volume enlargement. As the crack tip approached, a cavity volume enlargement occurred. Instead of the cavities continuing to enlarge until they touch, the walls between the cavities fractured. Fracture surface dimples do not correlate in size or density with these enlarged cavities

  6. Normal Conducting RF Cavity for MICE

    Energy Technology Data Exchange (ETDEWEB)

    Li, D.; DeMello, A.; Virostek, S.; Zisman, M.; Summers, D.

    2010-05-23

    Normal conducting RF cavities must be used for the cooling section of the international Muon Ionization Cooling Experiment (MICE), currently under construction at Rutherford Appleton Laboratory (RAL) in the UK. Eight 201-MHz cavities are needed for the MICE cooling section; fabrication of the first five cavities is complete. We report the cavity fabrication status including cavity design, fabrication techniques and preliminary low power RF measurements.

  7. Normal Conducting RF Cavity for MICE

    International Nuclear Information System (INIS)

    Normal conducting RF cavities must be used for the cooling section of the international Muon Ionization Cooling Experiment (MICE), currently under construction at Rutherford Appleton Laboratory (RAL) in the UK. Eight 201-MHz cavities are needed for the MICE cooling section; fabrication of the first five cavities is complete. We report the cavity fabrication status including cavity design, fabrication techniques and preliminary low power RF measurements.

  8. Cavity optomechanics and its applications

    Science.gov (United States)

    Bhattacharya, Mishkatul

    2009-05-01

    Cavity optomechanics is an emerging field at the intersection of quantum optics, atomic physics, nanoscience and gravitational wave interferometry. It involves cavities (with one or more mechanical degrees of freedom) driven by laser radiation. The ensuing optical control of macroscopic mechanical motion may have implications for precision sensing, coherent control of atoms and molecules, and quantum information processing. Due to recent innovations optomechanical physics has been realized in a variety of experimental systems spanning many orders of magnitude in mass and time-scales. In this talk, I will first introduce the basic paradigm of a laser-driven two mirror cavity used for cooling a vibrational mode. A three-mirror configuration recently implemented using a partially transmissive dielectric membrane in a high finesse cavity will then be discussed, and shown to be superior to the two-mirror design in a number of ways. One implication of the three-mirror configuration is the possibility of scaling optomechanical techniques to multiple oscillators. This topic will be explored by analysing the case of two membranes in a cavity where it will be shown that the collective(center-of-mass and breathing) modes of vibration can be cooled independently, analogous to a chain of trapped ions. Finally, future directions for possible applications to the control of atoms and molecules will be indicated briefly.

  9. Development of Side Coupled Cavities

    International Nuclear Information System (INIS)

    Side coupled Cavities are good candidates for proton accelerations in the 90-180 MeV range, as it has been first proposed for the CERN LINAC4 project. A side coupled Linac is made of a lump chain of resonant cavities, alternatively accelerating and coupling. A side coupled cavity has been designed in a CERN-LPSC collaboration to achieve LINAC4 requirements. After RF studies, a complete thermal study has been done, showing that 10-15% is the absolute maximum duty-cycle achievable by such a cavity. Error studies have been developed. They have shown that a tuning ring is mandatory and that a K equals 3% coupling factor is a good choice. A prototype has been built and each cell has been measured and tuned. A simple and accurate method has been used to get both the resonant frequency and the coupling factor, with a movable tuner and a linear fit. A similar method has been used to get the second order coupling factor. A large dispersion is observed on K. This is mainly due to the shape of the coupling apertures, which are very sensitive to mechanical errors. A future and realistic design must be very careful to guarantee a constant aperture (the important parameter is more the dispersion of k than its exact value). Finally, we analyse how to tune the cavity. This has to checked carefully and probably improved or corrected. Results are expected for mid-2008

  10. The ESS spoke cavity cryomodules

    Science.gov (United States)

    Bousson, Sebastien; Darve, Christine; Duthil, Patxi; Elias, Nuno; Molloy, Steve; Reynet, Denis; Thermeau, Jean-Pierre

    2014-01-01

    The European Spallation Source (ESS) is a multi-disciplinary research centre under design and construction in Lund, Sweden. This new facility is funded by a collaboration of 17 European countries and is expected to be up to 30 times brighter than today's leading facilities and neutron sources. The ESS will enable new opportunities for researchers in the fields of life sciences, energy, environmental technology, cultural heritage and fundamental physics. A 5 MW long pulse proton accelerator is used to reach this goal. The pulsed length is 2.86 ms, the repetition frequency is 14 Hz (4 % duty cycle), and the beam current is 62.5 mA. It is composed of one string of spoke cavity cryomodule and two strings of elliptical cavity cryomodules. This paper introduces the thermo-mechanical design and expected operation of the ESS spoke cavity cryomodules. These cryomodules contain two double spoke bulk Niobium cavities operating at 2 K and at a frequency of 352.21 MHz. The superconducting section of the Spoke Linac accelerates the beam from 90 MeV to 220 MeV. A Spoke Cavity Cryomodule Technology Demonstrator will be built and tested in order to validate the ESS series production.

  11. The ESS elliptical cavity cryomodules

    Science.gov (United States)

    Darve, Christine; Bosland, Pierre; Devanz, Guillaume; Olivier, Gilles; Renard, Bertrand; Thermeau, Jean-Pierre

    2014-01-01

    The European Spallation Source (ESS) is a multi-disciplinary research centre under design and construction in Lund, Sweden. This new facility is funded by a collaboration of 17 European countries and is expected to be up to 30 times brighter than today's leading facilities and neutron sources. The ESS will enable new opportunities for researchers in the fields of life sciences, energy, environmental technology, cultural heritage and fundamental physics. A 5 MW long pulse proton accelerator is used to reach this goal. The pulsed length is 2.86 ms, the repetition frequency is 14 Hz (4 % duty cycle), and the beam current is 62.5 mA. The superconducting section of the Linac accelerates the beam from 80 MeV to 2.0 GeV. It is composed of one string of spoke cavity cryomodule and two strings of elliptical cavity cryomodules. These cryomodules contain four elliptical Niobium cavities operating at 2 K and at a frequency of 704.42 MHz. This paper introduces the thermo-mechanical design, the prototyping and the expected operation of the ESS elliptical cavity cryomodules. An Elliptical Cavity Cryomodule Technology Demonstrator (ECCTD) will be built and tested in order to validate the ESS series production.

  12. A SURVEY OF CORONAL CAVITY DENSITY PROFILES

    International Nuclear Information System (INIS)

    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 Rsun 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 Rsun 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.

  13. Phoxonic crystals and cavity optomechanics

    Science.gov (United States)

    Djafari-Rouhani, Bahram; El-Jallal, Said; Pennec, Yan

    2016-05-01

    Phoxonic crystals are dual phononic/photonic crystals exhibiting simultaneously band gaps for both types of excitations. Therefore, they have the ability to confine phonons and photons in the same cavity and in turn allow the enhancement of their interaction. In this paper, we review some of our theoretical works on cavity optomechanical interactions in different types of phoxonic crystals, including two-dimensional, slab, and nanobeam structures. Two mechanisms are behind the phonon-photon interaction, namely the photoelastic and the moving interface effects. Coupling rates of a few MHz are obtained with high-frequency phonons of a few GHz. Finally, we give some preliminary results about the optomechanical interaction when a metallic nanoparticle is introduced into the cavity, giving rise to coupled photon-plasmon modes or, in the case of very small particles, to an enhancement of the electric field at the position of the particle. xml:lang="fr"

  14. Crab cavities for the LHC

    International Nuclear Information System (INIS)

    For the high-luminosity LHC upgrade program (HL-LHC), the installation of crab cavities (CC) is essential to compensate the geometric luminosity loss due to the crossing angle and for luminosity leveling. One of the major challenges is the compatibility with machine protection in the regime of >500 MJ stored beam energy. Especially in a failure case (e.g. a CC quench or sparking in the coupler), the voltage and/or phase of a CC can change significantly with a fast time-constant of the order of a LHC-turn. This can lead to large, global betatron oscillations of the beam. The status of the LHC crab cavity upgrade program is presented and the influence of crab cavities on the beam dynamics is discussed. Necessary countermeasures to limit the impact of CC failures to an acceptable level are specified and operational scenarios that are compatible with machine protection considerations are proposed.

  15. RRR Characteristics for SRF cavities

    Science.gov (United States)

    Jung, Yoochul; Hyun, Myungook; Joung, Mijoung

    2015-10-01

    The first heavy ion accelerator is being constructed by the rare isotope science project (RISP) launched by the Institute of Basic Science (IBS) in South Korea. Four different types of superconducting cavities were designed, and prototypes such as a quarter-wave resonator (QWR), a half-wave resonator (HWR) and a single-spoke resonator (SSR) were fabricated. One of the critical factors determining the performances of superconducting cavities is the residual resistance ratio (RRR). The RRR values essentially represent how pure niobium is and how fast niobium can transmit heat. In general, the RRR degrades during electron beam welding due to impurity incorporation. Thus, it is important to maintain the RRR above a certain value at which a niobium cavity shows target performance. In this study, RRR degradation related with electron beam welding conditions, for example, the welding power, welding speed, and vacuum level, will be discussed.

  16. RRR Characteristics for SRF Cavities

    CERN Document Server

    Jung, Yoochul; Joung, Mijoung

    2015-01-01

    The first heavy ion accelerator is being constructed by the rare isotope science project (RISP) launched by the Institute of Basic Science (IBS) in South Korea. Four different types of superconducting cavities were designed, and prototypes were fabricated such as a quarter wave resonator (QWR), a half wave resonator (HWR) and a single spoke resonator (SSR). One of the critical factors determining performances of the superconducting cavities is a residual resistance ratio (RRR). The RRR values essentially represent how much niobium is pure and how fast niobium can transmit heat as well. In general, the RRR degrades during electron beam welding due to the impurity incorporation. Thus it is important to maintain RRR above a certain value at which a niobium cavity shows target performance. In this study, RRR degradation related with electron beam welding conditions, for example, welding power, welding speed, and vacuum level will be discussed.

  17. Cavity Solitons in VCSEL Devices

    Directory of Open Access Journals (Sweden)

    S. Barbay

    2011-01-01

    Full Text Available We review advances on the experimental study of cavity solitons in VCSELs in the past decade. We emphasize on the design and fabrication of electrically or optically pumped broad-area VCSELs used for CSs formation and review different experimental configurations. Potential applications of CSs in the field of photonics are discussed, in particular the use of CSs for all-optical processing of information and for VCSELs characterization. Prospects on self-localization studies based on vertical cavity devices involving new physical mechanisms are also given.

  18. Radiography of the abdominal cavity

    International Nuclear Information System (INIS)

    Radiography is a very important part of the diagnostic procedure in many small animal diseases. Technically perfect X-rays are essential for the exact diagnosis. The general appearance of the abdominal cavity should be evaluated at first, e.g. the overall contrast and the definition of the visualized organs. Then particular attention should be paid, if there is any peritoneal effusion or free air in the peritoneal cavity. Subsequently each radiographically visible organ has to be evaluated for its position, size, shape and radiographic density

  19. Protein dynamics: hydration and cavities

    Directory of Open Access Journals (Sweden)

    K. Heremans

    2005-08-01

    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.

  20. Nanobeam Cavities for Reconfigurable Photonics

    OpenAIRE

    Deotare, Parag

    2012-01-01

    We investigate the design, fabrication, and experimental characterization of high quality factor photonic crystal nanobeam cavities, with theoretical quality factors of \\(1.4 × 10^7\\) in silicon, operating at ~1550 nm. By detecting the cross-polarized resonantly scattered light from a normally incident laser beam, we measure a quality factor of nearly \\(7.5 × 10^5\\). We show on-chip integration of the cavities using waveguides and an inverse taper geometry based mode size converters, and also...

  1. Synchronization in an optomechanical cavity.

    Science.gov (United States)

    Shlomi, Keren; Yuvaraj, D; Baskin, Ilya; Suchoi, Oren; Winik, Roni; Buks, Eyal

    2015-03-01

    We study self-excited oscillations (SEO) in an on-fiber optomechanical cavity. Synchronization is observed when the optical power that is injected into the cavity is periodically modulated. A theoretical analysis based on the Fokker-Planck equation evaluates the expected phase space distribution (PSD) of the self-oscillating mechanical resonator. A tomography technique is employed for extracting PSD from the measured reflected optical power. Time-resolved state tomography measurements are performed to study phase diffusion and phase locking of the SEO. The detuning region inside which synchronization occurs is experimentally determined and the results are compared with the theoretical prediction. PMID:25871175

  2. 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...... trachomatis, yeasts and viruses were taken preoperatively from the apex of the vagina and cervical os. Immediately after hysterectomy the uterus was opened under sterile conditions and samples obtained from the isthmus and fundus of the uterine cavity for microbiological examination. Wet smears were taken...

  3. Field emission in RF cavities

    International Nuclear Information System (INIS)

    Electron field emission limits the accelerating gradient in superconducting cavities. It is shown how and why it is an important problem. The phenomenology of field emission is then described, both in DC and RF regimes. Merits of a few plausible 'remedies' to field emission are discussed. (author)

  4. Nasal cavity and frontal sinuses

    International Nuclear Information System (INIS)

    The anatomy, diagnostic principles, and surgical techniques relating to the nasal cavity and frontal sinuses are reviewed. Disorders are considered under headings of infectious, neoplastic, and miscellaneous conditions. For each disease condition, an attempt is made to emphasize particular problems and discuss new developments on treatment. Specific recommendations have been made where possible, along with the expected outcome

  5. 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...

  6. Hydrofracture from a growing cavity

    International Nuclear Information System (INIS)

    The Los Alamos KRAK code has been used to calculate fracturing away from the growing cavity formed by a nuclear detonation. In the 55 ms before rebound, the stress in the surrounding rock is decreasing, and conditions for fracture propagation are good. During this interval, hydrofractures driven by the high-temperature, high-pressure gases within the cavity grow readily. Fracture growth slows when the stress increases as the residual hoop is formed during rebound. However, cracks are found to escape through the residual stress field. The effects of initial conditions and zoning on the numerical calculations are discussed, and the roles of the media saturation and roughness are briefly considered. The largest uncertainty in these calculations is the manner in which the effective pressure used in computing crack widths is extended into the cavity region. Because the present calculations have been done using a very conservative scheme, actual fractures should grow even more readily. We conclude that hydrofracture is an important, if not dominant, process in transporting mass and energy out of a cavity formed by a nuclear detonation

  7. Cavity length below chute aerators

    Institute of Scientific and Technical Information of China (English)

    WU JianHua; RUAN ShiPing

    2008-01-01

    It is proved that air entrainment is one of the efficient measures dealing with cavitation control for the release works of hydropower projects. There are many factors to be considered in designing a chute aerator. One of the most important factors concerns the cavity length below the aerator, which has outstanding effects on air entrainment against cavitation damage. It is crucial to determine reasonable emergence angle for the calculation of the cavity length. In the present paper the overall effects of structural and hydraulic parameters on the emergence angle of the flow from the aerator were analyzed. Four improved expressions of the emergence angle with weight coefficient were investigated through experimental data of 68 points observed from 12 aerators of 6 hydropower projects, of both model and prototype, on the basis of error theory. A method to calculate the cavity length below aerators was suggested, which considers overall effects of the above mentioned parameters. Comparison between the method in this paper and the other five methods of calculating the cavity length showed that the present method is much more reliable than the existing methods while the mean error of the method is less than others.

  8. Cavity length below chute aerators

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    It is proved that air entrainment is one of the efficient measures dealing with cavi-tation control for the release works of hydropower projects. There are many factors to be considered in designing a chute aerator. One of the most important factors concerns the cavity length below the aerator,which has outstanding effects on air entrainment against cavitation damage. It is crucial to determine reasonable emergence angle for the calculation of the cavity length. In the present paper the overall effects of structural and hydraulic parameters on the emergence angle of the flow from the aerator were analyzed. Four improved expressions of the emer-gence angle with weight coefficient were investigated through experimental data of 68 points observed from 12 aerators of 6 hydropower projects,of both model and prototype,on the basis of error theory. A method to calculate the cavity length be-low aerators was suggested,which considers overall effects of the above men-tioned parameters. Comparison between the method in this paper and the other five methods of calculating the cavity length showed that the present method is much more reliable than the existing methods while the mean error of the method is less than others.

  9. Large-mode enhancement cavities.

    Science.gov (United States)

    Carstens, Henning; Holzberger, Simon; Kaster, Jan; Weitenberg, Johannes; Pervak, Volodymyr; Apolonski, Alexander; Fill, Ernst; Krausz, Ferenc; Pupeza, Ioachim

    2013-05-01

    In passive enhancement cavities the achievable power level is limited by mirror damage. Here, we address the design of robust optical resonators with large spot sizes on all mirrors, a measure that promises to mitigate this limitation by decreasing both the intensity and the thermal gradient on the mirror surfaces. We introduce a misalignment sensitivity metric to evaluate the robustness of resonator designs. We identify the standard bow-tie resonator operated close to the inner stability edge as the most robust large-mode cavity and implement this cavity with two spherical mirrors with 600 mm radius of curvature, two plane mirrors and a round trip length of 1.2 m, demonstrating a stable power enhancement of near-infrared laser light by a factor of 2000. Beam radii of 5.7 mm × 2.6 mm (sagittal × tangential 1/e(2) intensity radius) on all mirrors are obtained. We propose a simple all-reflective ellipticity compensation scheme. This will enable a significant increase of the attainable power and intensity levels in enhancement cavities. PMID:23670017

  10. 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.

  11. Nanobeam cavities for Reconfigurable Photonics

    Science.gov (United States)

    Deotare, Parag B.

    We investigate the design, fabrication, and experimental characterization of high quality factor photonic crystal nanobeam cavities, with theoretical quality factors of 1.4 x 107 in silicon, operating at ˜ 1550 nm. By detecting the cross-polarized resonantly scattered light from a normally incident laser beam, we measure a quality factor of nearly 7.5 x 105. We show on-chip integration of the cavities using waveguides and an inverse taper geometry based mode size converters, and also demonstrate tuning of the optical resonance using thermo-optic effect. We also study coupled cavities and show that the single nanobeam cavity modes are coupled into even and odd superposition modes. Using electrostatic force and taking advantage of the highly dispersive nature of the even mode to the nanobeam separation, we demonstrate dynamically reconfigurable optical filters tunable continuously and reversibly over a 9.5 nm wavelength range. The electrostatic force, obtained by applying bias voltages directly to the nanobeams, is used to control the spacing between the nanobeams, which in turn results in tuning of the cavity resonance. The observed tuning trends were confirmed through simulations that modeled the electrostatic actuation as well as the optical resonances in our reconfigurable geometries. Finally we demonstrate reconfiguration of coupled cavities by using optical gradient force induced mechanical actuation. Propagating waveguide modes that exist over wide wavelength range are used to actuate the structures and in that way control the resonance of a localized cavity mode. Using this all-optical approach, more than 18 linewidths of tuning range is demonstrated. Using an on-chip temperature self-referencing method that we developed, we determined that 20% of the total tuning was due to optomechanical reconfiguration and the rest due to thermo-optic effects. By operating the device at frequencies higher than the thermal cut-off, we show high speed operation dominated by

  12. Generating photon pulses with an oscillating cavity

    OpenAIRE

    Lambrecht, A.(Laboratoire Kastler-Brossel, CNRS, ENS, Collège de France, UPMC, Campus Jussieu, 75252 Paris, France); Jaekel, M. T.; Reynaud, S

    1998-01-01

    We study the generation of photon pulses from thermal field fluctuations through opto-mechanical coupling to a cavity with an oscillatory motion. Pulses are regularly spaced and become sharp for a high finesse cavity.

  13. Coupled Photonic Crystal Cavity Array Laser

    DEFF Research Database (Denmark)

    Schubert, Martin

    quantum dots are carried out. In agreement with a simple gain model the structures do not show stimulated emission. The spectral splitting due to the coupling between single cavities as well as arrays of cavities is studied theoretically and experimentally. Lasing is observed for photonic crystal cavity......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...... structures with quantum wells. A detailed Analysis is conducted on single cavities, two coupled cavities and arrays of coupled cavities. The lasing threshold is determined by measuring the photoluminescence intensity depending on the excitation power. Changes in the linewidth and peak position for different...

  14. Operational experience with crab cavities at KEKB

    OpenAIRE

    Funakoshi, Y.; Group, for the KEKB Commissioning

    2014-01-01

    KEKB was in operation from December 1988 to June 2010. The crab cavities were installed at KEKB in February 2007 and worked very stably until the end of KEKB operation. Operational experience of the crab cavities with beams is described.

  15. Stages of Lip and Oral Cavity Cancer

    Science.gov (United States)

    ... common treatment for all stages of lip and oral cavity cancer. Surgery may include the following: Wide local excision : Removal ... cancer may have spread from the lip and oral cavity. Plastic surgery : An operation that restores or improves the appearance ...

  16. What Are Oral Cavity and Oropharyngeal Cancers?

    Science.gov (United States)

    ... Research Get Involved Find Local ACS Learn About Cancer » Oral Cavity and Oropharyngeal Cancer » Detailed Guide » What are ... how cancers start and spread, see What Is Cancer? Oral cavity cancer, or just oral cancer, is cancer ...

  17. Magnetosheath cavities: case studies using Cluster observations

    OpenAIRE

    Katırcıoğlu, F. T.; Z. Kaymaz; D. G. Sibeck; Dandouras, I.

    2009-01-01

    This paper presents examples of magnetosheath cavities in Cluster spacecraft observations. The cavities are accompanied by high energy particles in the magnetosheath and characterized by depressed magnetic fields and densities. Flow speeds decrease and temperatures increase within the cavities. All magnetosheath parameters show increased variability within the cavities when the energetic particle flux is high. We predict outward motion of the magnetopause boundary in respons...

  18. Parametric resonance in tunable superconducting cavities

    OpenAIRE

    Wustmann, Waltraut; Shumeiko, Vitaly

    2013-01-01

    We develop a theory of parametric resonance in tunable superconducting cavities. The nonlinearity introduced by the superconducting quantum interference device (SQUID) attached to the cavity and damping due to connection of the cavity to a transmission line are taken into consideration. We study in detail the nonlinear classical dynamics of the cavity field below and above the parametric threshold for the degenerate parametric resonance, featuring regimes of multistability and parametric radi...

  19. Prototype storage cavity for LEP accelerating RF

    CERN Multimedia

    1980-01-01

    The principle of an RF storage cavity was demonstrated with this prototype, working at 500 MHz. Ian Wilso seems to hold it in his hands. The storage cavities had 4 portholes, 1 each for: RF feed; tuning; connection to the accelerating cavity; vacuum pump. The final storage cavities were larger, to suit the lower LEP accelerating frequency of 352.2 MHz. See also 8002294, 8006510X, 8109346, 8407619X, and Annual Report 1980, p.115.

  20. Theory and technology for superconducting cavities

    CERN Document Server

    Lengeler, Herbert

    1993-01-01

    The course will address Physicist and Engineers who are newcomers in the field of accelerators and accelerating cavities. The elements of RF-Superconductivity will be presented with special relevance to accelerating cavities. The present ststus of achievable accelerating fields and RF losses will be given and their link to the special technologies for cavity fabrication and surface treatments will be stressed. Cavity auxiliaries like main couplers, higher order mode couplers and frequency tuners will be described.

  1. Cavity QED experiments with ion Coulomb crystals

    DEFF Research Database (Denmark)

    Herskind, Peter Fønss; Dantan, Aurélien; Marler, Joan; Albert, Magnus; Drewsen, Michael

    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....

  2. Cavity-water interface is polar

    OpenAIRE

    Friesen, Allan D.; Matyushov, Dmitry V.

    2010-01-01

    We present the results of numerical simulations of the electrostatics and dynamics of water hydration shells surrounding Kihara cavities given by a Lennard-Jones (LJ) layer at the surface of a hard-sphere cavity. The local dielectric response of the hydration layer substantially exceeds that of bulk water, with the magnitude of the dielectric constant peak in the shell increasing with the growing cavity size. The polar shell propagates into bulk water to approximately the cavity radius. The s...

  3. CLASSIFYING NODULAR LESIONS OF ORAL CAVITY

    OpenAIRE

    Sumit Bhateja

    2013-01-01

    Diagnosis of many lesions of the oral cavity is challenging to most cliniciansbecause of their uncommon prevalence. A number of cystic, osteodystrophic,microbial, tumor and tumor like lesions of the oral cavity are present withcharacteristic exophytic/raised surface; which makes their diagnosis and studysimpler. The present article is attempted at classifying the common nodular lesions ofthe oral cavity.

  4. Nanometer cavities studied by positron annihilation

    International Nuclear Information System (INIS)

    Positronium (Ps) is trapped in cavities in insulating solids, and the lifetime of ortho Ps is determined by the size of the cavity. The information on the properties of the cavities obtained by use of the standard slow positron beam and the 'normal' positron annihilation techniques is compared for several selected cases. (author)

  5. Computer codes for RF cavity design

    International Nuclear Information System (INIS)

    In RF cavity design, numerical modeling is assuming an increasingly important role with the help of sophisticated computer codes and powerful yet affordable computers. A description of the cavity codes in use in the accelerator community has been given previously. The present paper will address the latest developments and discuss their applications to cavity tuning and matching problems. (Author) 8 refs., 10 figs

  6. Computer codes for RF cavity design

    International Nuclear Information System (INIS)

    In RF cavity design, numerical modeling is assuming an increasingly important role with the help of sophisticated computer codes and powerful yet affordable computers. A description of the cavity codes in use in the accelerator community has been given previously. The present paper will address the latest developments and discuss their applications to cavity toning and matching problems

  7. Diffusion stabilizes cavity solitons in bidirectional lasers

    OpenAIRE

    Perez-Arjona, Isabel; Sanchez-Morcillo, Victor; Redondo, Javier; Staliunas, Kestutis; Roldan, Eugenio

    2009-01-01

    We study the influence of field diffusion on the spatial localized structures (cavity solitons) recently predicted in bidirectional lasers. We find twofold positive role of the diffusion: 1) it increases the stability range of the individual (isolated) solitons; 2) it reduces the long-range interaction between the cavity solitons. Latter allows the independent manipulation (writing and erasing) of individual cavity solitons.

  8. Power coupler for the ILC crab cavity

    Energy Technology Data Exchange (ETDEWEB)

    Burt, G.; Dexter, A.; Jenkins, R.; /Lancaster U.; Beard, C.; Goudket, P.; McIntosh, P.A.; /Daresbury; Bellantoni, Leo; /Fermilab

    2007-06-01

    The ILC crab cavity will require the design of an appropriate power coupler. The beam-loading in dipole mode cavities is considerably more variable than accelerating cavities, hence simulations have been performed to establish the required external Q. Simulations of a suitable coupler were then performed and were verified using a normal conducting prototype with variable coupler tips.

  9. Non-reacting flow visualization of supersonic combustor based on cavity and cavity-strut flameholder

    Science.gov (United States)

    Zhao, Yanhui; Liang, Jianhan; Zhao, Yuxin

    2016-04-01

    Nano-particle planer laser scattering and particle image velocimetry technology are employed to observe the flow field of scramjet combustors based on cavity and cavity-strut flameholder. Density field and velocity distribution inside combustors are obtained. Mainstream fluid enters into cavity nearby side wall in experimental observation because side wall shock waves interact with bottom wall boundary layer. Cavity fluid is entrained into mainstream in the middle of combustor meanwhile. Flow past cavity displays obvious three dimensional characteristics in both combustors. But cavity-strut combustor displays asymmetrical flow field because of strut configuration. Mass exchange between mainstream and cavity fluid is evaluated by statistic mass flow rate into cavity. Mass flow rate near side wall is raised to 6.62 times of the value in the middle of cavity combustor while it is 5.1 times in cavity-strut combustor. Further study is needed to injection strategies and realistic flow characteristics on condition of combustion.

  10. Status of the ILC Crab Cavity Development

    International Nuclear Information System (INIS)

    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.

  11. 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.

  12. A micropillar for cavity optomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, Aurélien; Neuhaus, Leonhard; Deléglise, Samuel; Briant, Tristan; Cohadon, Pierre-François; Heidmann, Antoine [Laboratoire Kastler Brossel, UPMC-ENS-CNRS, Paris (France); Van Brackel, Emmanuel [Département de Physique, ENS, Paris (France); Chartier, Claude; Ducloux, Olivier; Le Traon, Olivier [Département Mesures Physiques, ONERA, Châtillon (France); Michel, Christophe; Pinard, Laurent; Flaminio, Raffaele [Laboratoire des Matériaux Avancés, IN2P3-CNRS, Lyon (France)

    2014-12-04

    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.

  13. RF cavity vacuum interlock system

    Science.gov (United States)

    Jordan, K.; Crawford, K.; Bundy, R.; Dylla, H. F.; Heckman, J.; Marshall, J.; Nichols, R.; Osullivan, S.; Preble, J.; Robb, J.

    1992-03-01

    The Continuous Electron Beam Accelerator Facility (CEBAF), a continuous wave (CW) 4 GeV Electron Accelerator is undergoing construction in Newport News, Virginia. When completed in 1994, the accelerator will be the largest installation of radio-frequency superconductivity. Production of cryomodules, the fundamental building block of the machine, has started. A cryomodule consists of four sets of pairs of 1497 MHz, 5 cell niobium cavities contained in separate helium vessels and mounted in a cryostat with appropriate end caps for helium supply and return. Beam vacuum of the cavities, the connecting beam piping, the waveguides, and the cryostat insulating vacuum are crucial to the performance of the machine. The design and initial experience of the vacuum systems for the first 2 1/4 cryomodules that makeup the 45 MEV injector are discussed.

  14. Multi-color Cavity Metrology

    CERN Document Server

    Izumi, Kiwamu; Barr, Bryan; Betzwieser, Joseph; Brooks, Aidan; Dahl, Katrin; Doravari, Suresh; Driggers, Jennifer C; Korth, W Zach; Miao, Haixing; Rollins, Jameson; Vass, Stephen; Yeaton-Massey, David; Adhikari, Rana

    2012-01-01

    Long baseline laser interferometers used for gravitational wave detection have proven to be very complicated to control. In order to have sufficient sensitivity to astrophysical gravitational waves, a set of multiple coupled optical cavities comprising the interferometer must be brought into resonance with the laser field. A set of multi-input, multi-output servos then lock these cavities into place via feedback control. This procedure, known as lock acquisition, has proven to be a vexing problem and has reduced greatly the reliability and duty factor of the past generation of laser interferometers. In this article, we describe a technique for bringing the interferometer from an uncontrolled state into resonance by using harmonically related external fields to provide a deterministic hierarchical control. This technique reduces the effect of the external seismic disturbances by four orders of magnitude and promises to greatly enhance the stability and reliability of the current generation of gravitational wav...

  15. Tuberculosis involving the oral cavity

    OpenAIRE

    Ferguson, Kathleen A.; McCormack, David G

    1993-01-01

    The oral cavity is a rare site for extrapulmonary tuberculosis. A case is reported of a young woman with dysphagia and oral ulceration. The original mucosal biopsy was negative on smear for acid-fast bacilli, and the patient subsequently developed pulmonary symptoms. A diagnosis of Mycobacterium tuberculosis was ultimately made on open lung biopsy. Complete resolution of both mouth lesion and chest involvement occurred with standard antituberculous therapy.

  16. Quantum signalling in cavity QED

    OpenAIRE

    Jonsson, Robert H.; Martin-Martinez, Eduardo; Kempf, Achim

    2013-01-01

    We consider quantum signalling between two-level quantum systems in a cavity, in the pertubative regime of the earliest possible arrival times of the signal. We present two main results: First we find that, perhaps surprisingly, the analogue of amplitude modulated signalling (Alice using her energy eigenstates |g>, |e>, as in the Fermi problem) is generally sub-optimal for communication. Namely, e.g., phase modulated signalling (Alice using, e.g., |+>,|e>-states) overcomes the quantum noise a...

  17. Retention proposal in complex cavities.

    Directory of Open Access Journals (Sweden)

    Pedro Alvarez Rodríguez

    2003-12-01

    Full Text Available Background: Dental Operatory is the main structure in which Odontology lies. It is not an easy discipline that gives enjoyable results with little effort due to the difficulties that a correct reconstruction of a destroyed dental element offers.The frequency with which pulpar injury occurs while anchoring additional retainers in complex cavities, the technical difficulties the lack of these devices cause and the need to simplify dental procedures lead this study to show the advantages to substitute additional retainers for a retainer surcus. Method: An observational descriptive study was applied to 53 patients(42% of the universe , sample which was selected by means of a simple randomized sample . From a proximal-occlusal cavity, the preparations were extended in a box-like shape towards the bucal or lingual region and the additional retainers were substituted for a surcus which was performed in the gingival wall of the preparation. Calcium Hydroxide of rapid dryness was used as a cavity cover and Policarboxilate cement as a base; then the amalgam restoration was performed. The number of restorations were studied taking into account the patient´s age and the failures due to fractures of amalgam, loss of vitality and periapical changes were assessed taking into consideration the patient´s age and a one- year follow up. Results: Most of the amalgam restorations were performed in patients aged from 35 to 59 years and the relative frequencies due to fractures of amalgam, loss of vitality and periapical changes were very low. Conclusion: The substitution of additional retainers for a retainer surcus in complex cavities of vital molars showed to be advantageous because it guarantees a less degree of pulpar damage and less pulpar damage.

  18. CRAB Cavity in CERN SPS

    OpenAIRE

    Kim, H. J.; Sen, T.

    2012-01-01

    Beam collisions with a crossing angle at the interaction point have been applied in high intensity colliders to reduce the effects of parasitic collisions which induce emittance growth and beam lifetime deterioration. The crossing angle causes the geometrical reduction of the luminosity. Crab cavity can be one of the most promising ways to compensate the crossing angle and to realize effective head-on collisions. Moreover, the crab crossing mitigates the synchro-betatron resonances due to the...

  19. Retention proposal in complex cavities.

    OpenAIRE

    Pedro Alvarez Rodríguez; Eduardo M. Curbeira Hernández; Eduardo Duarte Marrero; Yisell Peláez Rivas; Aracelis Navarro Sánchez

    2003-01-01

    Background: Dental Operatory is the main structure in which Odontology lies. It is not an easy discipline that gives enjoyable results with little effort due to the difficulties that a correct reconstruction of a destroyed dental element offers.The frequency with which pulpar injury occurs while anchoring additional retainers in complex cavities, the technical difficulties the lack of these devices cause and the need to simplify dental procedures lead this study to show the advantages to subs...

  20. Superconducting versus normal conducting cavities

    OpenAIRE

    Podlech, Holger

    2013-01-01

    One of the most important issues of high-power hadron linacs is the choice of technology with respect to superconducting or room-temperature operation. The favour for a specific technology depends on several parameters such as the beam energy, beam current, beam power and duty factor. This contribution gives an overview of the comparison between superconducting and normal conducting cavities. This includes basic radiofrequency (RF) parameters, design criteria, limitations, required RF and plu...

  1. LHC crab-cavity aspects and strategy

    International Nuclear Information System (INIS)

    The 3rd LHC Crab Cavity workshop (LHC-CC09) took place at CERN in October 2009. It reviewed the current status and identified a clear strategy towards a future crab-cavity implementation. Following the success of crab cavities in KEK-B and the strong potential for luminosity gain and leveling, CERN will pursue crab crossing for the LHC upgrade. We present a summary and outcome of the variousworkshop sessions which have led to the LHC crab-cavity strategy, covering topics like layout, cavity design, integration, machine protection, and a potential validation test in the SPS.

  2. Cavity lining in primary teeth.

    Science.gov (United States)

    Chauhan, Ravi

    2016-03-01

    Data sourcesEmbase, Medline, Cochrane Central, Biomed Central and Open Grey databases and bibliographies of identified studies.Study selectionRandomised controlled trials investigating humans with primary caries lesions receiving operative treatment involving caries removal and restoration, with minimum two treatment groups comparing different cavity treatments before restoration (no lining versus lining) were included.Data extraction and synthesisData were extracted independently by two reviewers and study quality assessed using the Cochrane risk of bias tool. Random effect meta-analysis was carried out.ResultsThree studies involving a total of 89 patients were included. All the studies involved primary teeth and were conducted in Brazil. Follow-up periods ranged from 26-53 months. All the studies were considered to be at high risk of bias. Restoring the cavity without lining did not significantly affect the risk of failure. The quality of the evidence was low.ConclusionsCurrent evidence does not support strong recommendations to use or not to use liners after caries removal and before restoring cavities. Our findings are restricted to primary teeth after selective excavation, with only one liner (calcium hydroxide) being used for comparison. PMID:27012571

  3. Novel Geometries for the LHC Crab Cavity

    International Nuclear Information System (INIS)

    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 but the frequency cannot be increased any higher due to the long bunch length of the LHC beam. This will require a novel compact crab cavity design. A superconducting version of a two rod coaxial deflecting cavity as a suitable design is proposed in this paper.

  4. Construction of cavity fabrication facility in KEK

    International Nuclear Information System (INIS)

    In the development of the superconducting cavity for accelerator that is the main composition equipment of international linear collider (ILC), electron beam welding (EBW) becomes an important process on the cavity of which the Nb material is used. The technology of EBW influences the cavity performance that is cavity gradient. Because of EBW in the equator part of cavities and large amount of process is needed for cavity manufacturing process. In KEK we constructs the pilot plant where the superconducting cavity processing technology by EBW. A clean room was completed as of March of 2010, and the main process equipment except EBW and the CP processor were installed in a clean room. As for the EBW machine, it is scheduled to install it in March, 2011. (author)

  5. SPS RF System an Accelerating 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.

  6. Scaled experiments of explosions in cavities

    Science.gov (United States)

    Grun, J.; Cranch, G. A.; Lunsford, R.; Compton, S.; Walton, O. R.; Weaver, J.; Dunlop, W.; Fournier, K. B.

    2016-05-01

    Consequences of an explosion inside an air-filled cavity under the earth's surface are partly duplicated in a laboratory experiment on spatial scales 1000 smaller. The experiment measures shock pressures coupled into a block of material by an explosion inside a gas-filled cavity therein. The explosion is generated by suddenly heating a thin foil that is located near the cavity center with a short laser pulse, which turns the foil into expanding plasma, most of whose energy drives a blast wave in the cavity gas. Variables in the experiment are the cavity radius and explosion energy. Measurements and GEODYN code simulations show that shock pressures measured in the block exhibit a weak dependence on scaled cavity radius up to ˜25 m/kt1/3, above which they decrease rapidly. Possible mechanisms giving rise to this behavior are described. The applicability of this work to validating codes used to simulate full-scale cavity explosions is discussed.

  7. CHECHIA cavity driving with FPGA controller

    International Nuclear Information System (INIS)

    The initial control of the superconductive cavity has recently been performed by applying the FPGA (Field Programmable Gate Array) technology system in DESY Hamburg. This first experiment turned attention to the general recognition of the cavity features and projected control methods. The electrical model of the cavity is taken as a consideration origin. The calibration of the signal channel is considered as a key preparation for an efficient cavity driving. The cavity parameters identification is confirmed as a proper approach for the required performance: driving on resonance during filling and field stabilization during flattop time with reasonable power consumption. The feed-forward and feedback modes were applied successfully for the CHECHIA cavity driving. Representative results of experiments are presented for different levels of the cavity field gradient. (orig.)

  8. 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

  9. Observation and characterization of cavity Rydberg polaritons

    Science.gov (United States)

    Ningyuan, Jia; Georgakopoulos, Alexandros; Ryou, Albert; Schine, Nathan; Sommer, Ariel; Simon, Jonathan

    2016-04-01

    We experimentally demonstrate the emergence of a robust quasiparticle, the cavity Rydberg polariton, when an optical cavity photon hybridizes with a collective Rydberg excitation of a laser-cooled atomic ensemble. Free-space Rydberg polaritons have recently drawn intense interest as tools for quantum information processing and few-body quantum science. Here, we explore the properties of their cavity counterparts in the single-particle sector, observing an enhanced lifetime and slowed dynamics characteristic of cavity dark polaritons. We measure the range of cavity frequencies over which the polaritons persist, corresponding to the spectral width available for polariton quantum dynamics, and the speed limit for quantum information processing. Further, we observe a cavity-induced suppression of inhomogeneous broadening channels and demonstrate the formation of Rydberg polaritons in a multimode cavity. In conjunction with recent demonstrations of Rydberg-induced cavity nonlinearities, our results point the way towards using cavity Rydberg polaritons as a platform for creating high-fidelity photonic quantum materials and, more broadly, indicate that cavity dark polaritons offer enhanced stability and control uniquely suited to optical quantum information processing applications beyond the Rydberg paradigm.

  10. Cavities Formation in Sedimentary Deposits

    Czech Academy of Sciences Publication Activity Database

    Kulaviak, Lukáš; Růžička, Marek; Drahoš, Jiří; Hladil, Jindřich

    Bratislava: Slovak Society of Chemical Engineering , 2008 - (Markoš, J.), s. 241 ISBN 978-80-227-2903-1. [35th International Conference of Slovak Society of Chemical Engineering . Tatranské Matliare (SK), 26.05.2008-30.05.2008] R&D Projects: GA ČR GA104/07/1110; GA ČR GA104/06/1418; GA AV ČR IAAX00130702; GA ČR GP104/06/P287 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z30130516 Keywords : suspension * cavities * stromatactis Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  11. Broadband tuning of optomechanical cavities

    Science.gov (United States)

    Wiederhecker, Gustavo S.; Manipatruni, Sasikanth; Lee, Sunwoo; Lipson, Michal

    2011-01-01

    We demonstrate broadband tuning of an optomechanical microcavity optical resonance by exploring the large optomechanical coupling of a double-wheel microcavity and its uniquely low mechanical stiffness. Using a pump laser with only 13 mW at telecom wavelengths we show tuning of the silicon nitride microcavity resonances over 32 nm. This corresponds to a tuning power efficiency of only 400 $\\mu$W/nm. By choosing a relatively low optical Q resonance ($\\approx$18,000) we prevent the cavity from reaching the regime of regenerative optomechanical oscillations. The static mechanical displacement induced by optical gradient forces is estimated to be as large as 60 nm.

  12. Mass renormalization in cavity QED

    International Nuclear Information System (INIS)

    We show that the presence of a background medium and a boundary surface or surfaces in cavity QED produces no change in the energy shift of a free charged particle due to its coupling to the fluctuating electromagnetic field of the vacuum. This clarifies that the electromagnetic and the observed mass of the charged particle are not affected by the modification of the field of the vacuum. The calculations are nonrelativistic and restricted to the dipole approximation but are otherwise based on the general requirements of causality.

  13. Broadband Tuning of Optomechanical Cavities

    OpenAIRE

    Wiederhecker, Gustavo S.; Manipatruni, Sasikanth; Lee, Sunwoo; Lipson, Michal

    2010-01-01

    We demonstrate broadband tuning of an optomechanical microcavity optical resonance by exploring the large optomechanical coupling of a double-wheel microcavity and its uniquely low mechanical stiffness. Using a pump laser with only 13 mW at telecom wavelengths we show tuning of the silicon nitride microcavity resonances over 32 nm. This corresponds to a tuning power efficiency of only 400 $\\mu$W/nm. By choosing a relatively low optical Q resonance ($\\approx$18,000) we prevent the cavity from ...

  14. Broadband Tuning of Optomechanical Cavities

    CERN Document Server

    Wiederhecker, Gustavo S; Lee, Sunwoo; Lipson, Michal

    2010-01-01

    We demonstrate broadband tuning of an optomechanical microcavity optical resonance by exploring the large optomechanical coupling of a double-wheel microcavity and its uniquely low mechanical stiffness. Using a pump laser with only 13 mW at telecom wavelengths we show tuning of the silicon nitride microcavity resonances over 32 nm. This corresponds to a tuning power efficiency of only 400 $\\mu$W/nm. By choosing a relatively low optical Q resonance ($\\approx$18,000) we prevent the cavity from reaching the regime of regenerative optomechanical oscillations. The static mechanical displacement induced by optical gradient forces is estimated to be as large as 60 nm.

  15. Basketballs as spherical acoustic cavities

    Science.gov (United States)

    Russell, Daniel A.

    2010-06-01

    The sound field resulting from striking a basketball is found to be rich in frequency content, with over 50 partials in the frequency range of 0-12 kHz. The frequencies are found to closely match theoretical expectations for standing wave patterns inside a spherical cavity. Because of the degenerate nature of the mode shapes, explicit identification of the modes is not possible without internal investigation with a microphone probe. A basketball proves to be an interesting application of a boundary value problem involving spherical coordinates.

  16. Deterministic cavity quantum electrodynamics with trapped ions

    International Nuclear Information System (INIS)

    We have employed radio-frequency trapping to localize a single 40Ca+-ion in a high-finesse optical cavity. By means of laser Doppler cooling, the position spread of the ion's wavefunction along the cavity axis was reduced to 42 nm, a fraction of the resonance wavelength of ionized calcium (λ = 397 nm). By controlling the position of the ion in the optical field, continuous and completely deterministic coupling of ion and field was realized. The precise three-dimensional location of the ion in the cavity was measured by observing the fluorescent light emitted upon excitation in the cavity field. The single-ion system is ideally suited to implement cavity quantum electrodynamics under cw conditions. To this end we operate the cavity on the D3/2-P1/2 transition of 40Ca+ (λ 866 nm). Applications include the controlled generation of single-photon pulses with high efficiency and two-ion quantum gates

  17. Silicon Integrated Cavity Optomechanical Transducer

    Science.gov (United States)

    Zou, Jie; Miao, Houxun; Michels, Thomas; Liu, Yuxiang; Srinivasan, Kartik; Aksyuk, Vladimir

    2013-03-01

    Cavity optomechanics enables measurements of mechanical motion at the fundamental limits of precision imposed by quantum mechanics. However, the need to align and couple devices to off-chip optical components hinders development, miniaturization and broader application of ultrahigh sensitivity chip-scale optomechanical transducers. Here we demonstrate a fully integrated and optical fiber pigtailed optomechanical transducer with a high Q silicon micro-disk cavity near-field coupled to a nanoscale cantilever. We detect the motion of the cantilever by measuring the resonant frequency shift of the whispering gallery mode of the micro-disk. The sensitivity near the standard quantum limit can be reached with sub-uW optical power. Our on-chip approach combines compactness and stability with great design flexibility: the geometry of the micro-disk and cantilever can be tailored to optimize the mechanical/optical Q factors and tune the mechanical frequency over two orders of magnitudes. Electrical transduction in addition to optical transduction was also demonstrated and both can be used to effectively cool the cantilever. Moreover, cantilevers with sharp tips overhanging the chip edge were fabricated to potentially allow the mechanical cantilever to be coupled to a wide range of off-chip systems, such as spins, DNA, nanostructures and atoms on clean surfaces.

  18. Malignant melanoma of the oral cavity

    OpenAIRE

    M.S. Hashemi Pour

    2006-01-01

    Oral malignant melanoma is a rare disease. The common sites of its occurrence are the palate and gingiva with the maxillary arch being affected 80% of the time. Because of their presence at relatively obscure areas in the oral cavity, most of the malignant melanomas of the oral cavity are diagnosed at a late stage. These lesions are associated with poor prognosis. The dental clinician must therefore carefully examine the head, neck, and oral cavity, and any pigmented lesion that may ex...

  19. Hybrid Microwave-Cavity Heat Engine

    OpenAIRE

    Bergenfeldt, Christian; Samuelsson, Peter; Sothmann, Björn; Flindt, Christian; Büttiker, Markus

    2013-01-01

    We propose and analyze the use of hybrid microwave cavities as quantum heat engines. A possible realization consists of two macroscopically separated quantum dot conductors coupled capacitively to the fundamental mode of a microwave cavity. We demonstrate that an electrical current can be induced in one conductor through cavity-mediated processes by heating up the other conductor. The heat engine can reach Carnot efficiency with optimal conversion of heat to work. When the system delivers the...

  20. Effects of subsurface cavity expansion in clays

    OpenAIRE

    Au, SKA; Yeung, AT; Soga, K; Cheng, YM

    2007-01-01

    Subsurface cavity expansion in clay induced by compaction grouting can generate upward displacement of clay and/or increase in effective stress leading to consolidation, resulting in settlement compensation and/or shear strength enhancement respectively. However, the two potential benefits of subsurface cavity expansion may offset each other. Experiments and numerical simulations on the engineering behaviour of E-grade kaolin induced by subsurface pressure-controlled cavity expansion were con...

  1. Development of a cavity enhanced aerosol albedometer

    OpenAIRE

    Zhao, W.; Xu, X.; Dong, M.; Chen, W.; X. Gu; Hu, C; Huang, Y.; Gao, X; Huang, W.; Zhang, W

    2014-01-01

    We report on the development of a cavity enhanced aerosol single scattering albedometer incorporating incoherent broad-band cavity-enhanced spectroscopy (IBBCEAS) approach and an integrating sphere (IS) for simultaneous in situ measurements of aerosol scattering and extinction coefficients in the exact same sample volume. The cavity enhanced albedometer employed a blue light-emitting diode (LED) based IBBCEAS approach for the measurement of wavelength-resolv...

  2. Status of ERL superconducting spoke cavity development

    International Nuclear Information System (INIS)

    We have launched a 5-year research program to develop superconducting spoke cavity for laser Compton scattered (LCS) photon sources. For realizing a wide use of LCS X-ray and gamma-ray sources in academic and industrial applications, we adopt 325-MHz superconducting spoke cavity to electron beam drivers. In this paper, we present our developing status of cavity shape optimization and fabrication design. (author)

  3. Theory of clustered-cavity gyroklystron

    Science.gov (United States)

    Nusinovich, G. S.; Antonsen, T. M.; Guo, H.; Granatstein, V. L.

    2002-09-01

    An analytical theory of a new device configuration, a clustered-cavity gyroklystron, is developed. The device considered has two clusters of cavities: an input cluster and an output cluster. The results show that, by using a cluster cavity concept, the bandwidth of gyroklystrons can be enlarged significantly without sacrifice of gain or efficiency which may lead to the development of a new type of high power, moderate bandwidth millimeter-wave amplifier. The theory has also been used to analyze the effect of stagger tuning between cavity frequencies within a single cluster, as well as between different clusters on the bandwidth and gain of the device.

  4. Single-mode cavity with HOMs absorber

    International Nuclear Information System (INIS)

    We present a new 500 MHz cavity which has a simple damped structure for the 1.5 GeV high-brilliant VUV ring. The feature of the cavity design is that higher-order modes (HOMs) propagate out from the cavity through the beam duct with a large diameter and are absorbed in resistive parts in the duct. A low power measurement on a prototype model of the cavity was carried out and the Q-values of HOMs were confirmed to strongly reduce. Thus the coupled-bunch instabilities due to HOMs are expected to be sufficiently suppressed. (author)

  5. Design studies of SSC coupled cavity linac

    International Nuclear Information System (INIS)

    The SSC coupled cavity linac (CCL) will be a side coupled structure operating at 1284 MHz to accelerate a nominal 25 mA H- beam from 70 MeV to 600 MeV. The authors present results of both cavity design and beam dynamics studies. Each accelerating cavity is optimized by SUPERFISH; coupled cavity characteristics in the region of low-, mid- and high-energies are checked by MAFIA-3D. MAFIA-3D was also used to design the bridge coupler systems. The beam dynamics and error analysis are simulated by CCLDYN and CCLTRACE. Possible future upgrade of the CCL to 1 GeV is also discussed

  6. Optimization of a lasertron double output cavity

    International Nuclear Information System (INIS)

    Double output cavities have been used experimentally to increase the efficiency of high-power klystrons. We have used particle-in-cell simulations with the 2 + 1/2 dimensional code MASK to optimize the design of double output cavities for the lasertron under development at SLAC. We discuss design considerations for double output cavities (e.g., optimum choice of voltages and phases, efficiency, wall interception, breakdown). We describe how one calculates the cavity impedance matrix from the gap voltages and phases. Some results of the effect of varying voltage, perveance, and pulse are reported

  7. Introductory lecture on waveguides and cavities

    International Nuclear Information System (INIS)

    This lecture has two parts: waveguides and cavities. Basic topics are discussed which can serve as bases for the following lectures. Many of the results obtained in the first part concerning waveguides are applied in the second part in the discussion on cavity properties, since a cavity can be considered as a part of a waveguide, a cavity resonant mode being a superposition of two counter-travelling waves in the waveguide. In deriving most of the mathematical formulas, complex number representation - that is, phasor forms - are used. For the final results, however, real number representations are also provided as much as possible as an aid to a more intuitive understanding. (author)

  8. 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.

  9. 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.

  10. Generation of Cluster States in Cavity QED

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yan-Li; YANG Li-Jia; DAI Hong-Yi

    2007-01-01

    We propose two schemes for the generation of cluster states in the context of cavity quantum electrodynamics (QED).In the first scheme,we prepare multi-cavity cluster states with information encoded in the coherent states.The second scheme is to generate multi-atom cluster states,where qubits are represented by the states of cascade Rydberg atoms.Both the schemes are based on the atom-cavity interaction and the atomic spontaneous radiation can be effciently reduced since the cavity frequency is largely detuned from the atomic transition frequency.

  11. Design of the ILC Crab Cavity System

    International Nuclear Information System (INIS)

    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

  12. 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 to......We present a principle for the temperature stabilization of photonic crystal (PhC) cavities based on optofluidics. We introduce an analytic method enabling a specific mode of a cavity to be made wavelength insensitive to changes in ambient temperature. Using this analysis, we experimentally...

  13. Optically coupled cavities for wavelength switching

    International Nuclear Information System (INIS)

    An optical bistable device which presents hysteresis behavior is proposed and experimentally demonstrated. The system finds applications in wavelength switching, pulse reshaping and optical bistability. It is based on two optically coupled cavities named master and slave. Each cavity includes a semiconductor optical amplifier (SOA), acting as the gain medium of the laser, and two pair of fiber Bragg gratings (FBG) which define the lasing wavelength (being different in each cavity). Finally, a variable optical coupler (VOC) is employed to couple both cavities. Experimental characterization of the system performance is made analyzing the effects of the coupling coefficient between the two cavities and the driving current in each SOA. The properties of the hysteretic bistable curve and switching can be controlled by adjusting these parameters and the loss in the cavities. By selecting the output wavelength (λ1 or λ2) with an external filter it is possible to choose either the invert or non-invert switched signal. Experiments were developed employing both optical discrete components and a photonic integrated circuit. They show that for 8 m-long cavities the maximum switching frequency is about 500 KHz, and for 4 m-long cavities a minimum rise-time about 21 ns was measured. The switching time can be reduced by shortening the cavity lengths and using photonic integrated circuits.

  14. Engineering topological materials in microwave cavity arrays

    CERN Document Server

    Anderson, Brandon M; Owens, Clai; Schuster, David I; Simon, Jonathan

    2016-01-01

    We present a scalable architecture for the exploration of interacting topological phases of photons in arrays of microwave cavities, using established techniques from cavity and circuit quantum electrodynamics. A time-reversal symmetry breaking (non-reciprocal) flux is induced by coupling the microwave cavities to ferrites, allowing for the production of a variety of topological band structures including the $\\alpha=1/4$ Hofstadter model. Effective photon-photon interactions are included by coupling the cavities to superconducting qubits, and are sufficient to produce a $\

  15. Fabrication of Glass Micro-Cavities for Cavity QED Experiments

    CERN Document Server

    Roy, Arpan

    2011-01-01

    We report a process for fabricating high quality, defect-free spherical mirror templates suitable for developing high finesse optical Fabry-Perot resonators. The process utilizes the controlled reflow of borosilicate glass and differential pressure to produce mirrors with 0.3 nanometer surface roughness. The dimensions of the mirrors are in the 0.5-5mm range making them suitable candidates for integration with on-chip neutral atom and ion experiments where enhanced interaction between atoms and photons are required. Moreover the mirror curvature, dimension and placement is readily controlled and the process can easily provide an array of such mirrors. We show that cavities constructed with these mirror templates are well suited to quantum information applications such as single photon sources and atom-photon entanglement.

  16. Optimization of the output cavity for a three cavity X-band gyroklystron amplifier

    International Nuclear Information System (INIS)

    Experimental results of the Univ. of Maryland three-cavity gyroklystron indicate that interactions past the output cavity have enhanced the tube's efficiency. The tube operated at 10 GHz in the TE01 mode. At beam parameters of 425 kV, 204 A, and α=0.7, the three-cavity gyroklystron produced 27 MW at 32% efficiency with gain of 36 dB and pulse energy of 39 J. Four different three-cavity circuits were studied experimentally. These circuits differed mainly in the geometry of the output cavity. Each of these circuits was found to have two distinct operating regimes, which were controlled by the magnetic guide field taper across the circuit. By observing the effects of perturbing the guide field after the output cavity; and using an electric field probe in the output cavity it is shown that one regime corresponds to a CARM-like interaction after the output cavity

  17. Controlling dipole squeezing of two atoms inside a cavity via manipulating an atom outside the cavity

    Institute of Scientific and Technical Information of China (English)

    Liu Tang-Kun; Wang Ji-Suo; Feng Jian; Zhan Ming-Sheng

    2004-01-01

    Considering that three two-level atoms are initially in the GHZ single state and two of the atoms are simultaneously put into a cavity initially in the coherent state, we investigate the dipole squeezing properties of the two atoms inside the cavity under the condition of resonant interaction. It is shown that dipole squeezing properties of the two atoms inside the cavity are strongly affected by rotation manipulating of the atom outside the cavity.

  18. 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.

  19. Superconducting cavities developments efforts at RRCAT

    International Nuclear Information System (INIS)

    Superconducting RE cavities are the work-horse for many existing and proposed linear accelerators. Raja Ramanna Centre for Advanced Technology (RRCAT) has initiated a comprehensive R and D program for development of Superconducting RF cavities suitable for high energy accelerator application like SNS and ADS. For the initial phase of technology demonstration several prototype 1.3 GHz single cell-cavities have been developed. The work began with development of prototype single cell cavities in aluminum and copper. This helped in development of cavity manufacturing process, proving various tooling and learning on various mechanical and RF qualification processes. The parts manufacturing was done at RRCAT and Electron beam welding was carried out at Indian industry. These cavities further served during commissioning trials for various cavity processing infrastructure being developed at RRCAT and are also a potential candidate for Niobium thin film deposition R and D. Based on the above experience, few single cell cavities were developed in fine grain niobium. The critical technology of forming and machining of niobium and the intermediate RF qualification were developed at RRCAT. The EB welding of bulk niobium cavities was carried out in collaboration with IUAC, New Delhi at their facility. As a next logical step efforts are now on for development of multicell cavities. The prototype dumbbells and end group made of aluminium, comprising of RF and HOM couplers ports have also been developed, with their LB welding done at Indian industry. In this paper we shall present the development efforts towards manufacturing of 1.3 GHz single cell cavities and their initial processing and qualification. (author)

  20. External cavity quantum cascade laser

    International Nuclear Information System (INIS)

    In this paper we review the progress of the development of mid-infrared quantum cascade lasers (QCLs) operated in an external cavity configuration. We concentrate on QCLs based on the bound-to-continuum design, since this design is especially suitable for broadband applications. Since they were first demonstrated, these laser-based tunable sources have improved in performance in terms of output power, duty cycle, operation temperature and tuneability. Nowadays they are an interesting alternative to FTIRs for some applications. They operate at room temperature, feature a high spectral resolution while being small in size. They were successfully used in different absorption spectroscopy techniques. Due to their vast potential for applications in industry, medicine, security and research, these sources enjoy increasing interest within the research community as well as in industry. (topical review)

  1. Cavity Voltage Phase Modulation MD

    CERN Document Server

    Mastoridis, T; Butterworth, A; Molendijk, J; Tuckmantel, J

    2012-01-01

    The LHC RF/LLRF system is currently setup for extremely stable RF voltage to minimize transient beam loading eects. The present scheme cannot be extended beyond nominal beam current since the demanded power would push the klystrons to saturation. For beam currents above nominal (and possibly earlier), the cavity phase modulation by the beam will be not be corrected (transient beam loading), but the strong RF feedback and One-Turn Delay feedback will still be active for loop and beam stability in physics. To achieve this, the voltage set point will be adapted for each bunch. The goal of this MD was to test an iterative algorithm that would adjust the voltage set point to achieve the optimal phase modulation for klystron forward power considerations.

  2. Cavity pressure history of contained nuclear explosions

    International Nuclear Information System (INIS)

    Knowledge of pressure in cavities created by contained nuclear explosions is useful for estimating the possibility of venting radioactive debris to the atmosphere. Measurements of cavity pressure, or temperature, would be helpful in evaluating the correctness of present code predictions of underground explosions. In instrumenting and interpreting such measurements it is necessary to have good theoretical estimates of cavity pressures. In this paper cavity pressure is estimated at the time when cavity growth is complete. Its subsequent decrease due to heat loss from the cavity to the surrounding media is also predicted. The starting pressure (the pressure at the end of cavity growth) is obtained by adiabatic expansion to the final cavity size of the vaporized rock gas sphere created by the explosion. Estimates of cavity size can be obtained by stress propagation computer codes, such as SOC and TENSOR. However, such estimates require considerable time and effort. In this paper, cavity size is estimated using a scheme involving simple hand calculations. The prediction is complicated by uncertainties in the knowledge of silica water system chemistry and a lack of information concerning possible blowoff of wall material during cavity growth. If wall material blows off, it can significantly change the water content in the cavity, compared to the water content in the ambient media. After cavity growth is complete, the pressure will change because of heat loss to the surrounding media. Heat transfer by convection, radiation and conduction is considered, and its effect on the pressure is calculated. Analysis of cavity heat transfer is made difficult by the complex nature of processes which occur at the wall where melting, vaporization and condensation of the gaseous rock can all occur. Furthermore, the melted wall material could be removed by flowing or dripping to the cavity floor. It could also be removed by expansion of the steam contained in the melt (blowoff) and by

  3. Scheme for Implementation of Quantum Game in Cavity QED

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-Chun; CAO Shu-Ai; WU Yue-Qin; FANG Mao-Fa; LI Huai-Fan; ZHENG Xiao-Juan; ZHAO Ren; WANG Xin-Wen; LI Ze-Hua

    2008-01-01

    We propose an experimentally feasible scheme to implement two-player quantum game in cavity quantum electrodynamics (QED). During the process, the cavity is only virtually excited, thus our scheme is insensitive to the cavity field states and cavity decay. The scheme can be realized in the range of current cavity QED techniques.

  4. Scheme for Implementation of Quantum Game in Cavity QED

    International Nuclear Information System (INIS)

    We propose an experimentally feasible scheme to implement two-player quantum game in cavity quantum electrodynamics (QED). During the process, the cavity is only virtually excited, thus our scheme is insensitive to the cavity field states and cavity decay. The scheme can be realized in the range of current cavity QED techniques.

  5. Carcinomas of the nasal cavity

    International Nuclear Information System (INIS)

    Between 1969-1985, 45 patients with carcinomas of the nasal cavity proper received curative treatment. Of these, 30 had squamous cell carcinoma, 1 un-differentiated carcinoma, 9 adenocarcinoma and 5 adenoid cystic carcinoma. 18 Patients were treated with definitive radiotherapy (interstitial brachy-therapy in 5 patients and external beam therapy in 13 patients), 27 received surgery and radiotherapy. Median length of follow-up was 11 years (range 2.8-16.8 years). 36 Patients had no evidence of disease at the last follow-up visit. All 14 patients with carcinoma of nasal septum had the disease controlled. 9/31 Patients with lesions of lateral wall and floor died of the disease, 5 of uncontrolled local disease, 2 of distant metastases, 2 of both. Disease specific survival rates at 5 and 10 years were 83 and 80%, the corresponding overall survival rates were 75 and 60%. Blindness occurred in 4 patients, 2 due to orbital exenteration and 2 to radiation injury to the cornea and optic pathway. Other infrequent side effects were bone necrosis, dental decay, nasal stenosis and septal perforation. This study indicated that prognosis of patients with nasal cavity carcinoma was better than that of patients with maxillary sinus cancer treated during the same era. In addition, the study showed that carcinoma of the nasal septum were smaller than those of lateral wall and floor at diagnosis, so that excellent control could be achieved by definitive radiotherapy; when accessible, interstitial brachytherapy might be the treatment of choice in such patients. (author). 18 refs.; 4 figs.; 2 tabs

  6. Cavity Pressure Behaviour in Micro Injection Moulding

    DEFF Research Database (Denmark)

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

    2010-01-01

    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...

  7. Spallation neutron source RF cavity bias system

    International Nuclear Information System (INIS)

    The Spallation Neutron Source r.f. cavity bias system is described under the topic headings: bias system, r.f. cavity, cables, d.c. bias power supply, transistor regulator and control system. Calculation of 4 core 300 mm solid aluminium cable inductance, coaxial shunt frequency response and transistor regulator computed frequency response, are discussed in appendices 1-3. (U.K.)

  8. Cavity-enhanced absorption for optical refrigeration

    CERN Document Server

    Seletskiy, Denis V; Sheik-Bahae, Mansoor

    2009-01-01

    A 20-fold increase over the single path optical absorption is demonstrated with a low loss medium placed in a resonant cavity. This has been applied to laser cooling of Yb:ZBLAN glass resulting in 90% absorption of the incident pump light. A coupled-cavity scheme to achieve active optical impedance matching is analyzed.

  9. Agent for roentgenocontrast examination of cavities

    International Nuclear Information System (INIS)

    The water-soluble agent, additionaly containing starch, agar, water, is suggested to increase accuracy of injured cavity diagnostics. The method for roentgenocontrast agent preparation on the base of starch-agar gel is described. Advantages of the agent suggested in comparison with those of roentgenologic cavity investigation used are shown

  10. Large grain cavities from pure niobium ingot

    Science.gov (United States)

    Myneni, Ganapati Rao; Kneisel, Peter; Cameiro, Tadeu

    2012-03-06

    Niobium cavities are fabricated by the drawing and ironing of as cast niobium ingot slices rather than from cold rolled niobium sheet. This method results in the production of niobium cavities having a minimum of grain boundaries at a significantly reduced cost as compared to the production of such structures from cold rolled sheet.

  11. High-current SRF cavity design

    Science.gov (United States)

    Meidlinger, D.; Grimm, T. L.; Hartung, W.

    2006-07-01

    For high current applications, it is desirable for the cavity shape to have a low longitudinal loss factor and to have a high beam-breakup threshold current. This paper briefly describes three different cavities designed for this purpose: a six-cell elliptical cavity for particles traveling at the speed of light, a two-cell elliptical cavity for subluminal particle speeds, and a single cell cavity which uses the TM012 mode for acceleration. SUPERFISH simulations predict the peak fields in both of the elliptical cavities will not exceed the TeSLA values by more than 10% but both will have 28.7% larger apertures. The elliptical designs assume the bunch frequency equals the accelerating mode frequency. The beam pipe radius is chosen so that the cutoff frequency is less than twice that of the accelerating mode. Hence all of the monopole and dipole higher-order modes (HOMs) that can be driven by the beam have low loaded Q values. This simplifies the problem of HOM damping. The TM012 cavity is predicted to have much higher peak fields than a π-mode elliptical cavity, but offers potential advantages from its simplified shape; it is essentially a circular waveguide with curved end plates. This basic shape results in easier fabrication and simplified tuning.

  12. High-current SRF cavity design

    International Nuclear Information System (INIS)

    For high current applications, it is desirable for the cavity shape to have a low longitudinal loss factor and to have a high beam-breakup threshold current. This paper briefly describes three different cavities designed for this purpose: a six-cell elliptical cavity for particles traveling at the speed of light, a two-cell elliptical cavity for subluminal particle speeds, and a single cell cavity which uses the TM012 mode for acceleration. SUPERFISH simulations predict the peak fields in both of the elliptical cavities will not exceed the TeSLA values by more than 10% but both will have 28.7% larger apertures. The elliptical designs assume the bunch frequency equals the accelerating mode frequency. The beam pipe radius is chosen so that the cutoff frequency is less than twice that of the accelerating mode. Hence all of the monopole and dipole higher-order modes (HOMs) that can be driven by the beam have low loaded Q values. This simplifies the problem of HOM damping. The TM012 cavity is predicted to have much higher peak fields than a π-mode elliptical cavity, but offers potential advantages from its simplified shape; it is essentially a circular waveguide with curved end plates. This basic shape results in easier fabrication and simplified tuning

  13. Superconducting accelerating four-cell cavity

    CERN Multimedia

    1980-01-01

    A close view of the four-cell cavity. This was a prototype designed for LEP2 (LEP1 had warm copper cavities as accelerating elements). The first successful tests were made in December 1980 - reaching a Q = 10^6. (see photo 8012650X)

  14. 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...

  15. Cavity cooling below the recoil limit.

    Science.gov (United States)

    Wolke, Matthias; Klinner, Julian; Keßler, Hans; Hemmerich, Andreas

    2012-07-01

    Conventional laser cooling relies on repeated electronic excitations by near-resonant light, which constrains its area of application to a selected number of atomic species prepared at moderate particle densities. Optical cavities with sufficiently large Purcell factors allow for laser cooling schemes, avoiding these limitations. Here, we report on an atom-cavity system, combining a Purcell factor above 40 with a cavity bandwidth below the recoil frequency associated with the kinetic energy transfer in a single photon scattering event. This lets us access a yet-unexplored regime of atom-cavity interactions, in which the atomic motion can be manipulated by targeted dissipation with sub-recoil resolution. We demonstrate cavity-induced heating of a Bose-Einstein condensate and subsequent cooling at particle densities and temperatures incompatible with conventional laser cooling. PMID:22767925

  16. Optomechanical photon shuttling between photonic cavities

    CERN Document Server

    Li, Huan

    2014-01-01

    Mechanical motion of photonic devices driven by optical forces provides a profound means of coupling between optical fields. The current focus of these optomechanical effects has been on cavity optomechanics systems in which co-localized optical and mechanical modes interact strongly to enable wave-mixing between photons and phonons and backaction cooling of mechanical modes. Alternatively, extended mechanical modes can also induce strong nonlocal effects on propagating optical fields or multiple localized optical modes at distances. Here, we demonstrate a novel multi-cavity optomechanical device: a "photon see-saw", in which torsional optomechanical motion can shuttle photons between two photonic crystal nanocavities. The resonance frequencies of the two cavities, one on each side of the see-saw, are modulated anti-symmetrically by the device's rotation. Pumping photons into one cavity excites optomechanical self-oscillation which strongly modulates the inter-cavity coupling and shuttles photons to the other...

  17. Air flow in a collapsing cavity

    CERN Document Server

    Peters, Ivo R; Lohse, Detlef; van der Meer, Devaraj

    2013-01-01

    We experimentally study the airflow in a collapsing cavity created by the impact of a circular disk on a water surface. We measure the air velocity in the collapsing neck in two ways: Directly, by means of employing particle image velocimetry of smoke injected into the cavity and indirectly, by determining the time rate of change of the volume of the cavity at pinch-off and deducing the air flow in the neck under the assumption that the air is incompressible. We compare our experiments to boundary integral simulations and show that close to the moment of pinch-off, compressibility of the air starts to play a crucial role in the behavior of the cavity. Finally, we measure how the air flow rate at pinch-off depends on the Froude number and explain the observed dependence using a theoretical model of the cavity collapse.

  18. Vertical external cavity surface emitting semiconductor lasers

    CERN Document Server

    Holm, M

    2001-01-01

    Active stabilisation showed a relative locked linewidth of approx 3 kHz. Coarse tuning over 7 nm was achieved using a 3-plate birefingent filter plate while fine-tuning using cavity length change allowed tuning over 250 MHz. Vertical external cavity semiconductor lasers have emerged as an interesting technology based on current vertical cavity semiconductor laser knowledge. High power output into a single transverse mode has attracted companies requiring good fibre coupling for telecommunications systems. The structure comprises of a grown semiconductor Bragg reflector topped with a multiple quantum well gain region. This is then included in an external cavity. This device is then optically pumped to promote laser action. Theoretical modelling of AIGaAs based VECSEL structures was undertaken, showing the effect of device design on laser characteristics. A simple 3-mirror cavity was constructed to assess the static characteristics of the structure. Up to 153 mW of output power was achieved in a single transver...

  19. HOM dampers for KEKB crab cavity

    International Nuclear Information System (INIS)

    KEKB accelerator is a high luminosity electron positron collider with high beam currents. Two crab cavities were installed in the KEKB ring in January 2007 and the crab crossing operation was started. The ferrite HOM dampers of the crab cavity successfully absorbed HOM powers more than 10 kW and enabled the cavity operation with high beam currents. KEKB recently achieved the world record of the luminosity of 21 nb-1s-1. The HOM dampers contributed to stable operations of the crab cavity at high beam currents. We will present HOM dampers for the crab cavity, absorbed HOM powers in the HOM dampers during high beam current operations and an addition of SiC HOM damper for higher beam current operations. (author)

  20. Casimir forces of metallic microstructures into cavities

    Science.gov (United States)

    Kenanakis, George; Soukoulis, Costas M.; Economou, Eleftherios N.

    2015-08-01

    A theoretical estimate of the Casimir force of a metallic structure embedded into a cubic cavity is proposed. We demonstrate that by calculating the eigenmodes of the system we can determine the Casimir force, which can be either attractive or repulsive, by simply changing the geometry of the structures relative to the walls of the cavity. In this analysis, several cases of structures are taken into account, from rectangular slabs to chiral "omega" particles, and the predicted data are consistent with recent literature. We demonstrate that the sidewalls of the studied cavity contribute decisively to the repulsive Casimir force between the system and the nearby top surface of the cavity. Finally, we provide evidence that the medium embedded into the studied cavity (and especially its permittivity) can change the intensity of the Casimir force, while its repulsive nature, once established (owing to favorable geometrical features), remains quite robust.

  1. Statistics of magnetoconductance in ballistic cavities

    International Nuclear Information System (INIS)

    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

  2. Niobium Cavity Electropolishing Modelling and Optimisation

    CERN Document Server

    Ferreira, L M A; Forel, S; Shirra, J A

    2013-01-01

    It’s widely accepted that electropolishing (EP) is the most suitable surface finishing process to achieve high performance bulk Nb accelerating cavities. At CERN and in preparation for the processing of the 704 MHz high-beta Superconducting Proton Linac (SPL) cavities a new vertical electropolishing facility has been assembled and a study is on-going for the modelling of electropolishing on cavities with COMSOL® software. In a first phase, the electrochemical parameters were taken into account for a fixed process temperature and flow rate, and are presented in this poster as well as the results obtained on a real SPL single cell cavity. The procedure to acquire the data used as input for the simulation is presented. The modelling procedure adopted to optimise the cathode geometry, aimed at a uniform current density distribution in the cavity cell for the minimum working potential and total current is explained. Some preliminary results on fluid dynamics is also briefly described.

  3. HIE-ISOLDE cavity production – results from thermal modelling of the cavity during sputtering

    CERN Document Server

    Kupiainen, P

    2013-01-01

    The HIE-ISOLDE project is in the phase of cavity production and optimization. Cavities are made of copper and sputtered niobium. We build an ANSYS model to model thermal distributions and heat flows in the cavity structure. We limited the analysis to handle the cavity during sputtering and investigated the effect of different coating power. The aim was to check how results compare to experimental data and vary boundary conditions to improve the model. With two boundary conditions (fixed room and cavity top temperatures), we observed a power loss due to fixed temperature, as expected. The temperature gradient between the bottom and top cavity did not reach the values of the experimental data. With one boundary condition (fixed temperature on sputtering chamber structure), the expected linear proportionality was observed clearly between the temperatures of the cavity and the power. The temperature gradients were also observed to increase with power. We observed an offset in the data compared to experimental dat...

  4. Prototype superconducting radio-frequency cavity for LEP

    CERN Multimedia

    1985-01-01

    This niobium superconducting cavity was part of the prototype stages for an upgrade to LEP, known as LEP-2. Superconducting cavities would eventually replace the traditional copper cavities and allow beam energies of 100 GeV.

  5. Cryogenic rf test of the first plasma etched SRF cavity

    OpenAIRE

    Upadhyay, J.; Palczewski, A.; Popović, S.; Valente-Feliciano, A. -M.; Im, D.; Phillips, L; Vušković, L.

    2016-01-01

    Plasma etching has a potential to be an alternative processing technology for superconducting radio frequency (SRF) cavities. An apparatus and a method are developed for plasma etching of the inner surfaces of SRF cavities. To test the effect of the plasma etching on the cavity rf performance, a 1497 MHz single cell SRF cavity is used. The single cell cavity is mechanically polished, buffer chemically etched afterwards and rf tested at cryogenic temperatures for a baseline test. This cavity i...

  6. Present status of superconducting cavity developments

    Energy Technology Data Exchange (ETDEWEB)

    Ouchi, Nobuo; Kusano, Joichi; Hasegawa, Kazuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    1997-11-01

    An R and D work of a superconducting (SC) cavity for the high intensity proton linac has begun at JAERI in collaboration with KEK. The RF field calculation and the structural analysis have been made to determine the cavity shape in the proton energy range between 100 and 1500 MeV. The results indicate the feasibility of a SC proton linac. A vertical test stand with clean room, water rinsing system, cavity evacuation pumping system, cryostat and data acquisition system has been installed to demonstrate the cavity performance. A single cell cavity of {beta}=0.5 has been fabricated and tested at the test stand to obtain the Q-value and the maximum surface electric field strength. The measured Q-values have been found to be high enough for our requirement while the field strength was limited to about 75% of the specification by the multipacting. We describe the preliminary design of the SC cavity, the overview of the vertical test stand and experimental results of the single cell cavity. (author)

  7. Present status of superconducting cavity developments

    International Nuclear Information System (INIS)

    An R and D work of a superconducting (SC) cavity for the high intensity proton linac has begun at JAERI in collaboration with KEK. The RF field calculation and the structural analysis have been made to determine the cavity shape in the proton energy range between 100 and 1500 MeV. The results indicate the feasibility of a SC proton linac. A vertical test stand with clean room, water rinsing system, cavity evacuation pumping system, cryostat and data acquisition system has been installed to demonstrate the cavity performance. A single cell cavity of β=0.5 has been fabricated and tested at the test stand to obtain the Q-value and the maximum surface electric field strength. The measured Q-values have been found to be high enough for our requirement while the field strength was limited to about 75% of the specification by the multipacting. We describe the preliminary design of the SC cavity, the overview of the vertical test stand and experimental results of the single cell cavity. (author)

  8. Preparation and handling of superconducting RF cavities

    International Nuclear Information System (INIS)

    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.)

  9. Optimized Multi-Ion Cavity Coupling

    Science.gov (United States)

    Begley, Stephen; Vogt, Markus; Gulati, Gurpreet Kaur; Takahashi, Hiroki; Keller, Matthias

    2016-06-01

    Recent technological advances in cavity quantum electrodynamics (CQED) are paving the way to utilize multiple quantum emitters confined in a single optical cavity. In such systems, it is crucially important to control the quantum mechanical coupling of individual emitters to the cavity mode. In this regard, combining ion trap technologies with CQED provides a particularly promising approach due to the well-established motional control over trapped ions. Here, we experimentally demonstrate coupling of up to five trapped ions in a string to a high-finesse optical cavity. By changing the axial position and spacing of the ions in a fully deterministic manner, we systematically characterize their coupling to the cavity mode through visibility measurements of the cavity emission. In good agreement with the theoretical model, the results demonstrate that the geometrical configuration of multiple trapped ions can be manipulated to obtain optimal cavity coupling. Our system presents a new ground for exploring CQED with multiple quantum emitters, enabled by the highly controllable collective light-matter interaction.

  10. Resonant-cavity antenna for plasma heating

    International Nuclear Information System (INIS)

    This patent describes a magnetic confinement plasma device having a plasma. The plasma is immersed in a strong magnetic field and confined within an evacuated plasma chamber. A wave launcher for launching electromagnetic waves in the range of frequencies of 10 MHz to 200 MHz energizes and thereby heats the plasma. The wave launcher is spaced-apart from the plasma. The wave launcher comprises: a resonant cavity, including resonant chamber walls for containing electromagnetic fields; connection means connecting the resonant cavity to a transmission line carrying electromagnetic wave energy to the resonant cavity; at least one capacitive reactive element, and at least one inductive reactive element disposed within the resonant cavity; the capacitive reactive member separated from the chamber walls of the resonant cavity by a first predefined gap, with the capacitive reactive member and the chamber walls of the resonant cavity oriented approximately tangential to the strong magnetic field; the capacitive and the inductive reactive elements spaced apart from the plasma a second predetermined distance which at least partially determines the frequency of the launched waves; and the resonant cavity cooperating with the capacitive and the inductive reactive elements so as to launch electromagnetic waves in the range of frequencies, toward the plasma

  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. Superconducting cavity driving with FPGA controller

    International Nuclear Information System (INIS)

    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.)

  13. Construction of cavity fabrication facility in KEK (2)

    International Nuclear Information System (INIS)

    In developing superconducting cavities for accelerator which are major components of the International Linear Collider (ILC), electron beam welding (EBW) is absolutely necessary because Nb material is used for cavities. The technology of EBW influences the cavity performance that is cavity accelerator gradient. Because of EBW in the equator part of cavities and large amount of process is needed for cavity manufacturing process. In KEK we constructed the cavity fabrication facility which is a pilot plant for the superconducting cavity processing technology. As of March in 2010, clean room was completed and the major equipment, the EBW and CP treatment equipment, have been installed in the clean room in April, 2011. (author)

  14. Demonstration of superconducting micromachined cavities

    International Nuclear Information System (INIS)

    Superconducting enclosures will be key components of scalable quantum computing devices based on circuit quantum electrodynamics. Within a densely integrated device, they can protect qubits from noise and serve as quantum memory units. Whether constructed by machining bulk pieces of metal or microfabricating wafers, 3D enclosures are typically assembled from two or more parts. The resulting seams potentially dissipate crossing currents and limit performance. In this letter, we present measured quality factors of superconducting cavity resonators of several materials, dimensions, and seam locations. We observe that superconducting indium can be a low-loss RF conductor and form low-loss seams. Leveraging this, we create a superconducting micromachined resonator with indium that has a quality factor of two million, despite a greatly reduced mode volume. Inter-layer coupling to this type of resonator is achieved by an aperture located under a planar transmission line. The described techniques demonstrate a proof-of-principle for multilayer microwave integrated quantum circuits for scalable quantum computing

  15. Cancer of the oral cavity

    International Nuclear Information System (INIS)

    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

  16. Demonstration of superconducting micromachined cavities

    Energy Technology Data Exchange (ETDEWEB)

    Brecht, T., E-mail: teresa.brecht@yale.edu; Reagor, M.; Chu, Y.; Pfaff, W.; Wang, C.; Frunzio, L.; Devoret, M. H.; Schoelkopf, R. J. [Department of Applied Physics, Yale University, New Haven, Connecticut 06511 (United States)

    2015-11-09

    Superconducting enclosures will be key components of scalable quantum computing devices based on circuit quantum electrodynamics. Within a densely integrated device, they can protect qubits from noise and serve as quantum memory units. Whether constructed by machining bulk pieces of metal or microfabricating wafers, 3D enclosures are typically assembled from two or more parts. The resulting seams potentially dissipate crossing currents and limit performance. In this letter, we present measured quality factors of superconducting cavity resonators of several materials, dimensions, and seam locations. We observe that superconducting indium can be a low-loss RF conductor and form low-loss seams. Leveraging this, we create a superconducting micromachined resonator with indium that has a quality factor of two million, despite a greatly reduced mode volume. Inter-layer coupling to this type of resonator is achieved by an aperture located under a planar transmission line. The described techniques demonstrate a proof-of-principle for multilayer microwave integrated quantum circuits for scalable quantum computing.

  17. Demonstration of superconducting micromachined cavities

    Science.gov (United States)

    Brecht, T.; Reagor, M.; Chu, Y.; Pfaff, W.; Wang, C.; Frunzio, L.; Devoret, M. H.; Schoelkopf, R. J.

    2015-11-01

    Superconducting enclosures will be key components of scalable quantum computing devices based on circuit quantum electrodynamics. Within a densely integrated device, they can protect qubits from noise and serve as quantum memory units. Whether constructed by machining bulk pieces of metal or microfabricating wafers, 3D enclosures are typically assembled from two or more parts. The resulting seams potentially dissipate crossing currents and limit performance. In this letter, we present measured quality factors of superconducting cavity resonators of several materials, dimensions, and seam locations. We observe that superconducting indium can be a low-loss RF conductor and form low-loss seams. Leveraging this, we create a superconducting micromachined resonator with indium that has a quality factor of two million, despite a greatly reduced mode volume. Inter-layer coupling to this type of resonator is achieved by an aperture located under a planar transmission line. The described techniques demonstrate a proof-of-principle for multilayer microwave integrated quantum circuits for scalable quantum computing.

  18. FPGA based real time RF cavity simulator for superconducting RF cavity

    International Nuclear Information System (INIS)

    RF cavity is one of the most important component in an accelerator, it is used for producing appropriate electromagnetic fields to accelerate the charged particles. The response of RF cavity to an input RF signal depends on the various operating conditions. Actual operating conditions of RF cavity are difficult to create in lab and also RF cavity is not easily available which limits the study and testing of RF systems that involve RF cavity. This calls for the requirement of a real time hardware model of the RF cavity which can be integrated with other RF systems for their testing in lab. This limitation is even more severe for superconducting RF cavities which need to be operated with the required cryogenics. Thus a real time hardware model of the superconducting RF cavity has been realized on FPGA. Real time RF Cavity simulator can be used to study the response of RF cavity under various operating conditions and for testing and optimization of other RF sub-systems particularly the Low Level RF feedback control systems in lab

  19. The nasal cavity microbiota of healthy adults

    OpenAIRE

    Bassis, Christine M.; Tang, Alice L.; Young, Vincent B.; Pynnonen, Melissa A

    2014-01-01

    Background The microbiota of the nares has been widely studied. However, relatively few studies have investigated the microbiota of the nasal cavity posterior to the nares. This distinct environment has the potential to contain a distinct microbiota and play an important role in health. Results We obtained 35,142 high-quality bacterial 16S rRNA-encoding gene sequence reads from the nasal cavity and oral cavity (the dorsum of the tongue and the buccal mucosa) of 12 healthy adult humans and dep...

  20. Clamshell microwave cavities having a superconductive coating

    Energy Technology Data Exchange (ETDEWEB)

    Cooke, D. Wayne (Los Alamos, NM); Arendt, Paul N. (Los Alamos, NM); Piel, Helmut (Wuppertal, DE)

    1994-01-01

    A microwave cavity including a pair of opposing clamshell halves, such halves comprised of a metal selected from the group consisting of silver, copper, or a silver-based alloy, wherein the cavity is further characterized as exhibiting a dominant TE.sub.011 mode is provided together with an embodiment wherein the interior concave surfaces of the clamshell halves are coated with a superconductive material. In the case of copper clamshell halves, the microwave cavity has a Q-value of about 1.2.times.10.sup.5 as measured at a temperature of 10K and a frequency of 10 GHz.

  1. Cavity-Controlled Chemistry in Molecular Ensembles

    Science.gov (United States)

    Herrera, Felipe; Spano, Frank C.

    2016-06-01

    The demonstration of strong and ultrastrong coupling regimes of cavity QED with polyatomic molecules has opened new routes to control chemical dynamics at the nanoscale. We show that strong resonant coupling of a cavity field with an electronic transition can effectively decouple collective electronic and nuclear degrees of freedom in a disordered molecular ensemble, even for molecules with high-frequency quantum vibrational modes having strong electron-vibration interactions. This type of polaron decoupling can be used to control chemical reactions. We show that the rate of electron transfer reactions in a cavity can be orders of magnitude larger than in free space for a wide class of organic molecular species.

  2. RF cavity evaluation with the code SUPERFISH

    International Nuclear Information System (INIS)

    The computer code SUPERFISH calculates axisymmetric rf fields and is most applicable to re-entrant cavities of an Alvarez linac. Some sample results are shown for the first Alvarez's in NUMATRON project. On the other hand the code can also be effectivily applied to TE modes excited in an RFQ linac when the cavity is approximately considered as positioning at an infinite distance from the symmetry axis. The evaluation was made for several RFQ cavities, models I, II and a test linac named LITL, and useful results for the resonator design were obtained. (author)

  3. 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....

  4. Cavity-controlled chemistry in molecular ensembles

    CERN Document Server

    Herrera, Felipe

    2015-01-01

    The demonstration of strong and ultrastrong coupling regimes of cavity QED with polyatomic molecules has opened new routes to control chemical dynamics at the nanoscale. We show that strong resonant coupling of a cavity field with an electronic transition can effectively decouple collective electronic and nuclear degrees of freedom in a disordered molecular ensemble, even for molecules with high-frequency quantum vibrational modes having strong electron-vibration interactions. This type of polaron decoupling can be used to control chemical reactions. We show that the rate of electron transfer reactions in a cavity can be orders of magnitude larger than in free space, for a wide class of organic molecular species.

  5. Shallow Cavities in Multiple-Planet Systems

    OpenAIRE

    Duffell, Paul C.; Dong, Ruobing

    2014-01-01

    Large cavities are often observed in protoplanetary disks, which might suggest the presence of planets opening gaps in the disk. Multiple planets are necessary to produce a wide cavity in the gas. However, multiple planets may also be a burden to the carving out of very deep gaps. When additional planets are added to the system, the time-dependent perturbations from these additional satellites can stir up gas in the gap, suppressing cavity opening. In this study, we perform two-dimensional nu...

  6. LHC Crab Cavity Coupler Test Boxes

    CERN Document Server

    Mitchell, James; Burt, Graeme; Calaga, Rama; Macpherson, Alick; Montesinos, Eric; Silva, Subashini; Tutte, Adam; Xiao, Binping

    2016-01-01

    The LHC double quarter wave (DQW) crab cavities have two different types of Higher Order Mode (HOM) couplers in addition to a fundamental power coupler (FPC). The FPC requires conditioning, so to achieve this we have designed a radio-frequency (RF) quarter wave resonator to provide high transmission between two opposing FPCs. For the HOM couplers we must ensure that the stop-band filter is positioned at the cavity frequency and that peak transmission occurs at the same frequencies as the strongest HOMs. We have designed two test boxes which preserve the cavity spectral response in order to test the couplers.

  7. Coherent cavity networks with complete connectivity

    OpenAIRE

    Kyoseva, Elica S.; Beige, Almut; Kwek, Leong Chuan

    2011-01-01

    When cavity photons couple to an optical fiber with a continuum of modes, they usually leak out within a finite amount of time. However, if the fiber is about one meter long and linked to a mirror, photons bounce back and forth within the fiber on a much faster time scale. As a result, {\\em dynamical decoupling} prevents the cavity photons from entering the fiber. In this paper we use the simultaneous dynamical decoupling of a large number of distant cavities from the fiber modes of linear op...

  8. Q degradations in superconducting niobium cavities

    International Nuclear Information System (INIS)

    In the past year, several laboratories around the world have observed degradations of the Q value of superconducting niobium cavities made from high thermal conductivity niobium under certain cooldown conditions. Especially under slow cooldown or warmup to temperatures < 200 K of larger systems severe degradations have been reported. A systematic study of the influence of the cooldown speed, warmup conditions, multiple cooldowns and chemical surface treatment on cavity performance of cavities manufactured from niobium of different purity has been conducted. Possible cures such as anodic oxidation are being explored and results of these investigations are reported

  9. Perturbing Open Cavities: Anomalous Resonance Frequency Shifts in a Hybrid Cavity-Nanoantenna System.

    Science.gov (United States)

    Ruesink, Freek; Doeleman, Hugo M; Hendrikx, Ruud; Koenderink, A Femius; Verhagen, Ewold

    2015-11-13

    The influence of a small perturbation on a cavity mode plays an important role in fields like optical sensing, cavity quantum electrodynamics, and cavity optomechanics. Typically, the resulting cavity frequency shift directly relates to the polarizability of the perturbation. Here, we demonstrate that particles perturbing a radiating cavity can induce strong frequency shifts that are opposite to, and even exceed, the effects based on the particles' polarizability. A full electrodynamic theory reveals that these anomalous results rely on a nontrivial phase relation between cavity and nanoparticle radiation, allowing backaction via the radiation continuum. In addition, an intuitive model based on coupled mode theory is presented that relates the phenomenon to retardation. Because of the ubiquity of dissipation, we expect these findings to benefit the understanding and engineering of a wide class of systems. PMID:26613442

  10. Striped-double cavity fabry-perot interferometers using both glass and air cavities

    Energy Technology Data Exchange (ETDEWEB)

    Perry, S; Steinmetz, L

    1998-07-08

    We have used piezo-driven Fabry-Perot interferometers in the past far many continuous velocity-time measurements of fast moving surfaces. In order to avoid the annoying drift of some of these devices, we have developed and used inexpensive, solid glass, striped etalons with lengths up to 64 mm. Usable apertures are 35 mm by 80 mm with a finess of 25. A roundabout technique was devised for double cavity operation. We built a passive thermal housing for temperature stability, with tilt and height adjustments. We have also developed and used our first fixed etalon air-spaced cavity with a rotatable glass double- cavity insert. The rotation allows the referee cavity fractional order to be adjusted separately from that of the main cavity. It needs very little thermal protection, and eliminates the need for a roundabout scheme for double cavity operation, but is more costly than the solid glass version I

  11. Ion-cavity system for quantum networks

    International Nuclear Information System (INIS)

    Full text: A single atom interacting with a single mode of a cavity allows us to probe the quantum interaction between light and matter. In the context of quantum networks, such a system can provide an interface between stationary and flying qubits, making it possible for single photons to transport quantum information between the network nodes. We study a single 40Ca+ ion trapped inside a high-finesse optical resonator. First, we demonstrate and characterize a single-photon source, in which a vacuum-stimulated Raman process transfers atomic population between two Zeeman states of the ion, creating a single photon in the cavity. We evaluate the photon statistics by measuring the second-order correlation function. Moreover, we obtain the photon temporal profile and investigate the dynamics of the process. Secondly, we perform Raman spectroscopy using the cavity. Residual motion of the ion introduces motional sidebands in the Raman spectrum and thus offers prospects for cavity-assisted cooling. (author)

  12. High-Q ferrite-tuned cavity

    International Nuclear Information System (INIS)

    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

  13. Working on an LHC superconducting cavity

    CERN Multimedia

    Laurent Guiraud

    2000-01-01

    The delicate superconducting equipment for CERN’s LHC collider has to be assembled in ultra-clean conditions to safeguard performance. Here we see the power supply being installed on one of the superconducting cavities.

  14. 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.

  15. On Catastrophe and Cavitation for Spherical Cavity

    Institute of Scientific and Technical Information of China (English)

    MingJIN; KefuHUANG; 等

    1999-01-01

    This work deals with catastrophe of a spherical cavity and cavitation of a spherical cavity for Hooke material with 1/2 Poisson's ratio.A nonlinear problem.which is the Cauchy traction problem,is solved analytically.The governing equations are written on the deformed region or on the present configuration.And the conditions are described on moving boundary.A closed form solution is found.Furthermore,a bifurcation solution in closed form is given from the trivial homogeneous solution of a solid sphere.The results indicate that there is a tangent bifurcation on the displacement-load curve for a sphere with a cavity.On the tangent bifurcation point,the cavity grows up suddenly,which is a kind of catastrophe,And there is a pitchfork bifurcation on the displacement-load curve for a solid sphere.On the pitchfork bifurcation point.there is a cavitation in the solid sphere.

  16. Photon filters in a microwave cavity

    CERN Document Server

    Larson, J

    2003-01-01

    In an earlier paper we have concluded that time-dependent parameters in atom-mode interaction can be utilized to modify the quantum field in a cavity. When an atom shoots through the cavity field, it is expected to experience a trigonometric time dependence of its coupling constant. We investigate the possibilities this offers to modify the field. As a point of comparison we use the solvable Rosen-Zener model, which has parameter dependencies roughly similar to the ones expected in a real cavity. We do confirm that by repeatedly sending atoms through the cavity, we can obtain filters on the photon states. Highly non-classical states can be obtained. We find that the Rosen-Zener model is more sensitive to the detuning than the case of a trigonometric coupling.

  17. Cavity-enhanced spectroscopy and sensing

    CERN Document Server

    Loock, Hans-Peter

    2014-01-01

    The book reviews the dramatic recent advances in the use of optical resonators for high sensitivity and high resolution molecular spectroscopy as well as for chemical, mechanical and physical sensing.  It encompasses a variety of cavities including those made of two or more mirrors, optical fiber loops, fiber gratings and spherical cavities. The book focuses on novel techniques and their applications. Each chapter is written by an expert and/or pioneer in the field. These experts also provide the theoretical background in optics and molecular physics where needed. Examples of recent breakthroughs include the use of frequency combs (Nobel prize 2005) for cavity enhanced sensing and spectroscopy, the use of novel cavity materials and geometries, the development of optical heterodyne detection techniques combined to active frequency-locking schemes. These methods allow the use and interrogation of optical resonators with a variety of coherent light sources for trace gas detection and sensing of strain, temperat...

  18. Malignant melanoma of the oral cavity

    Directory of Open Access Journals (Sweden)

    Ebenezer Jagadish

    2006-01-01

    Full Text Available Oral malignant melanoma is a rare disease. The common sites of its occurrence are the palate and gingiva with the maxillary arch being affected 80% of the time. Because of their presence at relatively obscure areas in the oral cavity, most of the malignant melanomas of the oral cavity are diagnosed at a late stage. These lesions are associated with poor prognosis. The dental clinician must therefore carefully examine the head, neck, and oral cavity, and any pigmented lesion that may exhibit growth potential must be biopsied. This article describes a case of malignant melanoma that was present in the oral cavity and briefly reviews the relevant literature that explains the nature of this lesion.

  19. Photonic crystal cavities with metallic Schottky contacts

    International Nuclear Information System (INIS)

    We report about the fabrication and analysis of high Q photonic crystal cavities with metallic Schottky-contacts. The structures are based on GaAs n-i membranes with an InGaAs quantum well in the i-region and nanostructured low ohmic metal top-gates. They are designed for photocurrent readout within the cavity and fast electric manipulations. The cavity structures are characterized by photoluminescence and photocurrent spectroscopy under resonant excitation. We find strong cavity resonances in the photocurrent spectra and surprisingly high Q-factors up to 6500. Temperature dependent photocurrent measurements in the region between 4.5 K and 310 K show an exponential enhancement of the photocurrent signal and an external quantum efficiency up to 0.26

  20. Reducing the convective losses of cavity receivers

    Science.gov (United States)

    Flesch, Robert; Grobbel, Johannes; Stadler, Hannes; Uhlig, Ralf; Hoffschmidt, Bernhard

    2016-05-01

    Convective losses reduce the efficiency of cavity receivers used in solar power towers especially under windy conditions. Therefore, measures should be taken to reduce these losses. In this paper two different measures are analyzed: an air curtain and a partial window which covers one third of the aperture opening. The cavity without modifications and the usage of a partial window were analyzed in a cryogenic wind tunnel at -173°C. The cryogenic environment allows transforming the results from the small model cavity to a large scale receiver with Gr≈3.9.1010. The cavity with the two modifications in the wind tunnel environment was analyzed with a CFD model as well. By comparing the numerical and experimental results the model was validated. Both modifications are capable of reducing the convection losses. In the best case a reduction of about 50 % was achieved.

  1. Wakefield Damping for the CLIC Crab Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Ambattu, P.K.; Burt, G.; Dexter, A.C.; Carter, R.G.; /Cockcroft Inst. Accel. Sci. Tech. /Lancaster U.; Khan, V.; Jones, R.M.; /Cockcroft Inst. Accel. Sci. Tech. /Manchester U.; Dolgashev, V.; /SLAC

    2011-12-01

    A crab cavity is required in the CLIC to allow effective head-on collision of bunches at the IP. A high operating frequency is preferred as the deflection voltage required for a given rotation angle and the RF phase tolerance for a crab cavity are inversely proportional to the operating frequency. The short bunch spacing of the CLIC scheme and the high sensitivity of the crab cavity to dipole kicks demand very high damping of the inter-bunch wakes, the major contributor to the luminosity loss of colliding bunches. This paper investigates the nature of the wakefields in the CLIC crab cavity and the possibility of using various damping schemes to suppress them effectively.

  2. Wakefield damping for the CLIC crab cavity

    CERN Document Server

    Ambattu, P K; Dexter, A C; Carter, R G; Khan, V; Jones, R M; Dolgashev, V

    2009-01-01

    A crab cavity is required in the CLIC to allow effective head-on collision of bunches at the IP. A high operating frequency is preferred as the deflection voltage required for a given rotation angle and the RF phase tolerance for a crab cavity are inversely proportional to the operating frequency. The short bunch spacing of the CLIC scheme and the high sensitivity of the crab cavity to dipole kicks demand very high damping of the inter-bunch wakes, the major contributor to the luminosity loss of colliding bunches. This paper investigates the nature of the wakefields in the CLIC crab cavity and the possibility of using various damping schemes to suppress them effectively.

  3. WAKEFIELD DAMPING FOR THE CLIC CRAB CAVITY

    CERN Document Server

    Ambattu, P; Dexter, A; Carter, R; Khan, V; Jones, R; Dolgashev, V

    2009-01-01

    A crab cavity is required in the CLIC to allow effective head-on collision of bunches at the IP. A high operating frequency is preferred as the deflection voltage required for a given rotation angle and the RF phase tolerance for a crab cavity are inversely proportional to the operating frequency. The short bunch spacing of the CLIC scheme and the high sensitivity of the crab cavity to dipole kicks demand very high damping of the inter-bunch wakes, the major contributor to the luminosity loss of colliding bunches. This paper investigates the nature of the wakefields in the CLIC crab cavity and the possibility of using various damping schemes to suppress them effectively.

  4. Nb3Sn for Radio Frequency Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Godeke, A.

    2006-12-18

    In this article, the suitability of Nb3Sn to improve theperformance of superconducting Radio-Frequency (RF)cavities is discussed.The use of Nb3Sn in RF cavitiesis recognized as an enabling technology toretain a veryhigh cavity quality factor (Q0) at 4.2 K and tosignificantly improve the cavity accelerating efficiency per unitlength(Eacc). This potential arises through the fundamental properties ofNb3Sn. The properties that are extensively characterized in theliterature are, however, mainly related to improvements in currentcarrying capacity (Jc) in the vortex state. Much less is available forthe Meissner state, which is of key importance to cavities. Relevantdata, available for the Meissner state is summarized, and it is shown howthis already validates the use of Nb3Sn. In addition, missing knowledgeis highlighted and suggestions are given for further Meissner statespecific research.

  5. LEP superconducting cavities go into storage

    CERN Multimedia

    Patrice Loïez

    2001-01-01

    Superconducting radio-frequency cavities from the LEP-2 phase (1996-2000) are put into storage in the tunnel that once housed the Intersecting Storage Rings (ISR), the world’s first proton collider, located at CERN.

  6. Barrier Cavities in the Brookhaven AGS

    International Nuclear Information System (INIS)

    In collaboration with KEK two barrier cavities, each generating 40 kV per turn have been installed in the Brookhaven AGS. Machine studies are described and their implications for high intensity operations are discussed

  7. Radiotherapy for Oral Cavity Cancer

    International Nuclear Information System (INIS)

    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 60Co 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

  8. A ''monochromatic'' RF-cavity

    International Nuclear Information System (INIS)

    The Electron-Positron-Accumulation ring (EPA)in the LEP injector chain acts as a particle buffer between the fast-cycling (100Hz) LEP Injector Linac (LIL) and the slow-cycling (0.8 Hz) CERN Proton Synchrotron (CPS). EPA has a circumference of 126m and has operated after start-up in June 1986 at 500 MeV. Only e- have been stored while e+ operation is scheduled for March 1987. The nominal EPA intensities are 2.5 X 1010 e- per bunch corresponding to a total current of 76 mA and 38 mA in 8 bunches. However, a current of 240 MA has already been stored. A nominal LIL pulse is 12 ns long but 25 ns is typical. The intensity is 9/pulse. In order to have a large longitudinal acceptance the lowest possible harmonic number h=8 was chosen for EPA yielding frf=19 MHz. The maximum r.f. voltage Vrf=50 kV is determined by the momentum acceptance (+-1.2%) of the bucket required by the e- LIL pulse. The longitudinal matching to the CPS did not impose further constraints except that adiabatic reduction of Vrf to about 10 kV prior to ejection is required if the CPS accelerates with frf=7.6 MHz. Since the 8 bunches are closely spaced, parasitic higher modes in the cavity have no time to decay. Therefore, efficient damping of these modes is required. Care was taken that other ring elements would not produce high-Q parasitic resonances

  9. The emission properties of an atom inside a cavity when manipulating the atoms outside the cavity

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wen; YE Liu; XIONG Kuang-wei; ZHANG Jin

    2003-01-01

    Considering three two-level atoms initially in the GHZ state, then one atom of them is put into an initially empty cavity and made resonant interaction. It is shown that the emission properties of the atom inside the cavity can be affected only when both of the atoms outside the cavity have been manipulated. This conclusion can also be generalized to n two-level atoms.

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

    CERN Multimedia

    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.

  11. Cavity QED on a nanofiber using a composite photonic crystal cavity

    CERN Document Server

    Yalla, Ramachandrarao; Nayak, Kali P; Hakuta, Kohzo

    2014-01-01

    We demonstrate cavity QED conditions in the Purcell regime for single quantum emitters on the surface of an optical nanofiber. The cavity is formed by combining an optical nanofiber and a nanofabricated grating to create a composite photonic crystal cavity. Using this technique, significant enhancement of the spontaneous emission rate into the nanofiber guided modes is observed for single quantum dots. Our results pave the way for enhanced on-fiber light-matter interfaces with clear applications to quantum networks.

  12. Electrically Pumped Vertical-Cavity Amplifiers

    DEFF Research Database (Denmark)

    Greibe, Tine

    2007-01-01

    In this work, the design of electrically pumped vertical cavity semiconductor optical amplifiers (eVCAs) for use in a mode-locked external-cavity laser has been developed, investigated and analysed. Four different eVCAs, one top-emitting and three bottom emitting structures, have been designed and...... discussed. The thesis concludes with recommendations for further work towards the realisation of compact electrically pumped mode-locked vertical externalcavity surface emitting lasers....

  13. Collapse of Non-Axisymmetric Cavities

    OpenAIRE

    Enriquez, Oscar R.; Peters, Ivo R.; Gekle, Stephan; Schmidt, Laura; Versluis, Michel; van der Meer, Devaraj; Lohse, Detlef

    2009-01-01

    A round disk with a harmonic disturbance impacts on a water surface and creates a non-axisymmetric cavity which collapses under the influence of hydrostatic pressure. We use disks deformed with mode m=2 to m=6. For all mode numbers we find clear evidence for a phase inversion of the cavity wall during the collapse. We present a fluid dynamics video showing high speed imaging of different modes, pointing out the characteristic features during collapse.

  14. Resonance control in SRF cavities at FNAL

    Energy Technology Data Exchange (ETDEWEB)

    Schappert, W.; Pischalnikov, Y.; /Fermilab; Scorrano, M.; /INFN, Pisa

    2011-03-01

    The Lorentz force can dynamically detune pulsed Superconducting RF cavities. Considerable additional RF power can be required to maintain the accelerating gradient if no effort is made to compensate for this detuning. Compensation systems using piezo actuators have been used successfully at DESY and elsewhere to control Lorentz Force Detuning (LFD). Recently, Fermilab has developed an adaptive compensation system for cavities in the Horizontal Test Stand, in the SRF Accelerator Test Facility, and for the proposed Project X.

  15. Comments on Crab Cavity HOM Power

    CERN Document Server

    Calaga, Rama; CERN. Geneva. ATS Department

    2013-01-01

    Due to large beam current in the LHC and the luminosity upgrade (HL-LHC) which will further double the current, higher order mode (HOM) power of the superconducting crab cavities can easily reach a few kilowatts in the worst case scenario of resonant excitation. This report aims at estimating the HOM power to be extracted for a generalized HOM of crab cavity with realistic filling schemes in the LHC.

  16. Dynamically Reconfigurable Photonic Crystal Nanobeam Cavities

    OpenAIRE

    Frank, Ian W.; Deotare, Parag B.; McCutcheon, Murray W.; Loncar, Marko

    2009-01-01

    Wavelength-scale, high Q-factor photonic crystal cavities have emerged as a platform of choice for on-chip manipulation of optical signals, with applications ranging from low-power optical signal processing and cavity quantum electrodynamics, to biochemical sensing. Many of these applications, however, are limited by the fabrication tolerances and the inability to precisely control the resonant wavelength of fabricated structures. Various techniques for post-fabrication wavelength trimming an...

  17. LHC Crab Cavity Progress and Outlook

    CERN Document Server

    Calaga, R

    2013-01-01

    Three novel superconducting RF crab cavity designs proposed for the LHC luminosity upgrade have rapidly progressed. First Niobium prototypes are reaching close to the design performance and beyond. The highlights of the RF test results from the prototypes along with design modifications for initial beam tests in the SPS are presented. The status of the cryomodule development, integration into the SPS and the beam tests in view of validating the crab cavity system for LHC upgrade are addressed.

  18. Beam induced RF cavity transient voltage

    International Nuclear Information System (INIS)

    We calculate the transient voltage induced in a radio frequency (RF) cavity by the injection of a relativistic bunched beam into a circular accelerator. A simplified model of the beam induced voltage, using a single tone current signal, is generated and compared with the voltage induced by a more realistic model of a point-like bunched beam. The high Q limit of the bunched beam model is shown to be related simply to the simplified model. Both models are shown to induce voltages at the resonant frequency ωr of the cavity and at an integer multiple of the bunch revolution frequency (i.e. the accelerating frequency for powered cavity operation) hω0. The presence of two nearby frequencies in the cavity leads to a modulation of the carrier wave exp(jhω0t). A special emphasis is placed in this paper on studying the modulation function. These models prove useful for computing the transient voltage induced in superconducting RF cavities, which was the motivation behind this research. The modulation of the transient cavity voltage discussed in this paper is the physical basis of the recently observed and explained new kind of longitudinal rigid dipole mode which differs from the conventional Robinson mode

  19. Study of CSR longitudinal bunch compression cavity

    International Nuclear Information System (INIS)

    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 238U72+ 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)

  20. Laser plasma interactions in fused silica cavities

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Xianzhong; Mao, Xianglei; Mao, Samuel S.; Yoo, Jong H.; Greif, Ralph; Russo, Richard E.

    2003-06-24

    The effect of laser energy on formation of a plasma inside a cavity was investigated. The temperature and electron number density of laser-induced plasmas in a fused silica cavity were determined using spectroscopic methods, and compared with laser ablation on a flat surface. Plasma temperature and electron number density during laser ablation in a cavity with aspect ratio of 4 increased faster with irradiance after the laser irradiance reached a threshold of 5 GW/cm{sup 2}. The threshold irradiance of particulate ejection was lower for laser ablation in a cavity compared with on a flat surface; the greater the cavity aspect ratio, the lower the threshold irradiance. The ionization of silicon becomes saturated and the crater depths were increased approximately by an order of magnitude after the irradiance reached the threshold. Phase explosion was discussed to explain the large change of both plasma characteristics and mass removal when irradiance increased beyond a threshold value. Self-focusing of the laser beam was discussed to be responsible for the decrease of the threshold in cavities.

  1. Flux expulsion variation in SRF cavities

    CERN Document Server

    Posen, S; Romanenko, A; Melnychuk, O; Sergatskov, D A; Martinello, M; Checchin, M; Crawford, A C

    2015-01-01

    Treating a cavity with nitrogen doping significantly increases $Q_0$ at medium fields, reducing cryogenic costs for high duty factor linear accelerators such as LCLS II. N-doping also makes cavities more sensitive to increased residual resistance due to trapped magnetic flux, making it critical to either have extremely effective magnetic shielding, or to prevent flux from being trapped in the cavity during cooldown. In this paper, we report on results of a study of flux expulsion. We discuss possible ways in which flux can be pinned in the inner surface, outer surface, or bulk of a cavity, and we present experimental results studying these mechanisms. We show that grain structure appears to play a key role and that a cavity that expelled flux poorly changed to expelling flux well after a high temperature furnace treatment. We further show that after furnace treatment, this cavity exhibited a significant improvement in quality factor when cooled in an external magnetic field. We conclude with implications for ...

  2. "Fine grain Nb tube for SRF cavities"

    Energy Technology Data Exchange (ETDEWEB)

    Robert E. Barber

    2012-07-08

    Superconducting radio frequency (SRF) cavities used in charged particle linear accelerators, are currently fabricated by deep drawing niobium sheets and welding the drawn dishes together. The Nb sheet has a non-uniform microstructure, which leads to unpredictable cavity shape and surface roughness, and inconsistent "spring-back" during forming. In addition, weld zones cause hot spots during cavity operation. These factors limit linear accelerator performance and increase cavity manufacturing cost. Equal channel angular extrusion (ECAE) can be used to refine and homogenize the microstructure of Nb tube for subsequent hydroforming into SRF cavities. Careful selection of deformation and heat treatment conditions during the processing steps can give a uniform and consistent microstructure in the tube, leading to improved deformability and lower manufacturing costs. Favorable microstructures were achieved in short test samples of RRR Nb tube, which may be particularly suitable for hydroforming into SRF cavity strings. The approach demonstrated could be applicable to microstructure engineering of other tube materials including tantalum, titanium, and zirconium.

  3. Cavity Mode Frequencies and Large Optomechanical Coupling in Two-Membrane Cavity Optomechanics

    CERN Document Server

    Li, J; Malossi, N; Vitali, D

    2015-01-01

    We study the cavity mode frequencies of a Fabry-Perot cavity containing two vibrating dielectric membranes and the corresponding optomechanical coupling. Due to optical interference, extremely large optomechanical coupling of the membrane relative motion is achieved when the two membranes are placed very close to a resonance of the inner cavity formed by the two membranes, and in the limit of highly reflective membranes. The upper bound of the coupling strength is given by the optomechanical coupling associated with the much shorter inner cavity, consistently with the analysis of A. Xuereb et al., Phys. Rev. Lett. 109, 223601 (2012).

  4. Vector cavity solitons in broad area Vertical-Cavity Surface-Emitting Lasers.

    Science.gov (United States)

    Averlant, Etienne; Tlidi, Mustapha; Thienpont, Hugo; Ackemann, Thorsten; Panajotov, Krassimir

    2016-01-01

    We report the experimental observation of two-dimensional vector cavity solitons in a Vertical-Cavity Surface-Emitting Laser (VCSEL) under linearly polarized optical injection when varying optical injection linear polarization direction. The polarization of the cavity soliton is not the one of the optical injection as it acquires a distinct ellipticity. These experimental results are qualitatively reproduced by the spin-flip VCSEL model. Our findings open the road to polarization multiplexing when using cavity solitons in broad-area lasers as pixels in information technology. PMID:26847004

  5. Teleportation of a Weak Coherent Cavity Field State

    Science.gov (United States)

    Cardoso, Wesley B.; Qiang, Wen-Chao; Avelar, Ardiley T.

    2016-07-01

    In this paper we propose a scheme to teleport a weak coherent cavity field state. The scheme relies on the resonant atom-field interaction inside a high-Q cavity. The mean photon-number of the cavity field is assumed much smaller than one, hence the field decay inside the cavity can be effectively suppressed.

  6. Teleportation of atomic states with a weak coherent cavity field

    Institute of Scientific and Technical Information of China (English)

    Zheng Shi-Biao

    2005-01-01

    A scheme is proposed for the teleportation of an unknown atomic state. The scheme is based on the resonant interaction of atoms with a coherent cavity field. The mean photon-number of the cavity field is much smaller than one and thus the cavity decay can be effectively suppressed. Another adwntage of the scheme is that only one cavity is required.

  7. 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. As...

  8. Teleportation of a Weak Coherent Cavity Field State

    Science.gov (United States)

    Cardoso, Wesley B.; Qiang, Wen-Chao; Avelar, Ardiley T.

    2016-02-01

    In this paper we propose a scheme to teleport a weak coherent cavity field state. The scheme relies on the resonant atom-field interaction inside a high-Q cavity. The mean photon-number of the cavity field is assumed much smaller than one, hence the field decay inside the cavity can be effectively suppressed.

  9. 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...

  10. Two cavity autoacceleration of an intense relativistic electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, P.D.; Lockner, T.R.

    1985-01-01

    Two autoacceleration cavities have been used to accelerate an 11-kA electron beam from 2 MeV to approx. =2.8 MeV. The two 40-..cap omega.. cavities each accelerated the beam by approx. =400 kV with no observable interaction between the two cavities over several cavity transmit times. 6 figs.

  11. Two cavity autoacceleration of an intense relativistic electron beam

    International Nuclear Information System (INIS)

    Two autoacceleration cavities have been used to accelerate an 11-kA electron beam from 2 MeV to approx. =2.8 MeV. The two 40-Ω cavities each accelerated the beam by approx. =400 kV with no observable interaction between the two cavities over several cavity transmit times. 6 figs

  12. Scheme for implementing quantum secret sharing via cavity QED

    Institute of Scientific and Technical Information of China (English)

    Chen Zhi-Hua; Lin Xiu-Min

    2005-01-01

    An experimentally feasible scheme for implementing quantum secret sharing via cavity quantum electrodynamics (QED) is proposed. The scheme requires the large detuning of the cavity field from the atomic transition, the cavity is only virtually excited, thus the requirement on the quality factor of the cavity is greatly loosened.

  13. IMRT in oral cavity cancer

    International Nuclear Information System (INIS)

    Except for early T1,2 N0 stages, the prognosis for patients with oral cavity cancer (OCC) is reported to be worse than for carcinoma in other sites of the head and neck (HNC). The aim of this work was to assess disease outcome in OCC following IMRT. Between January 2002 and January 2007, 346 HNC patients have been treated with curative intensity modulated radiation therapy (IMRT) at the Department of Radiation Oncology, University Hospital Zurich. Fifty eight of these (16%) were referred for postoperative (28) or definitive (30) radiation therapy of OCC. 40 of the 58 OCC patients (69%) presented with locally advanced T3/4 or recurred lesions. Doses between 60 and 70 Gy were applied, combined with simultaneous cisplatin based chemotherapy in 78%. Outcome analyses were performed using Kaplan Meier curves. In addition, comparisons were performed between this IMRT OCC cohort and historic in-house cohorts of 33 conventionally irradiated (3DCRT) and 30 surgery only patients treated over the last 10 years. OCC patients treated with postoperative IMRT showed the highest local control (LC) rate of all assessed treatment sequence subgroups (92% LC at 2 years). Historic postoperative 3DCRT patients and patients treated with surgery alone reached LC rates of ~70–80%. Definitively irradiated patients revealed poorest LC rates with ~30 and 40% following 3DCRT and IMRT, respectively. T1 stage resulted in an expectedly significantly higher LC rate (95%, n = 19, p < 0.05) than T2-4 and recurred stages (LC ~50–60%, n = 102). Analyses according to the diagnosis revealed significantly lower LC in OCC following definitive IMRT than that in pharyngeal tumors treated with definitive IMRT in the same time period (43% vs 82% at 2 years, p < 0.0001), while the LC rate of OCC following postoperative IMRT was as high as in pharyngeal tumors treated with postoperative IMRT (>90% at 2 years). Postoperative IMRT of OCC resulted in the highest local control rate of the assessed treatment

  14. JLab SRF Cavity Fabrication Errors, Consequences and Lessons Learned

    Energy Technology Data Exchange (ETDEWEB)

    Frank Marhauser

    2011-09-01

    Today, elliptical superconducting RF (SRF) cavities are preferably made from deep-drawn niobium sheets as pursued at Jefferson Laboratory (JLab). The fabrication of a cavity incorporates various cavity cell machining, trimming and electron beam welding (EBW) steps as well as surface chemistry that add to forming errors creating geometrical deviations of the cavity shape from its design. An analysis of in-house built cavities over the last years revealed significant errors in cavity production. Past fabrication flaws are described and lessons learned applied successfully to the most recent in-house series production of multi-cell cavities.

  15. Superconducting RF Cavity Frequency and Field Distribution Sensitivity Simulation

    CERN Document Server

    An, Sun

    2005-01-01

    Frequency and electromagnetic field distribution sensitivity of a superconducting RF (SRF) cavity due to cavity's small deformation are the fundamental phyical paramethers in cavity and tuner design. At low temperature, the frequency sensitivity can be obtained by measuring prototype cavity, but it is not easy to test the filed distribution sensitivity. This paper presents and describes a simulation method combining ANSYS and SUPERFISH to calculate the cavity frequency and field distribution variation due to cavity's small deformation caused by mechanical force, radiation force, thermal expansion etc.. As an example, the simulation results of the frequency and field flatness sensitivity on the SNS cavities were confirmed by their test results.

  16. Superconducting drift-tube cavity development for the RIA driver

    International Nuclear Information System (INIS)

    This paper reports the design and development of two intermediate-velocity superconducting cavities and design of an associated cryomodule for the RIA driver linac. The two cavity types are a 115 MHz, βGEOM = 0.15 quarter-wave resonant (QWR) cavity, and a 173 MHz, βGEOM = 0.26 half-wave loaded cavity. Both cavities are well-corrected for dipole and quadrupole asymmetries in the accelerating field. The cryomodule is being designed to incorporate a separate vacuum system for cavity vacuum to provide a particulate-free environment for the superconducting cavities

  17. Efficient Characterization of Protein Cavities within Molecular Simulation Trajectories: trj_cavity.

    Science.gov (United States)

    Paramo, Teresa; East, Alexandra; Garzón, Diana; Ulmschneider, Martin B; Bond, Peter J

    2014-05-13

    Protein cavities and tunnels are critical in determining phenomena such as ligand binding, molecular transport, and enzyme catalysis. Molecular dynamics (MD) simulations enable the exploration of the flexibility and conformational plasticity of protein cavities, extending the information available from static experimental structures relevant to, for example, drug design. Here, we present a new tool (trj_cavity) implemented within the GROMACS ( www.gromacs.org ) framework for the rapid identification and characterization of cavities detected within MD trajectories. trj_cavity is optimized for usability and computational efficiency and is applicable to the time-dependent analysis of any cavity topology, and optional specialized descriptors can be used to characterize, for example, protein channels. Its novel grid-based algorithm performs an efficient neighbor search whose calculation time is linear with system size, and a comparison of performance with other widely used cavity analysis programs reveals an orders-of-magnitude improvement in the computational cost. To demonstrate its potential for revealing novel mechanistic insights, trj_cavity has been used to analyze long-time scale simulation trajectories for three diverse protein cavity systems. This has helped to reveal, respectively, the lipid binding mechanism in the deep hydrophobic cavity of a soluble mite-allergen protein, Der p 2; a means for shuttling carbohydrates between the surface-exposed substrate-binding and catalytic pockets of a multidomain, membrane-proximal pullulanase, PulA; and the structural basis for selectivity in the transmembrane pore of a voltage-gated sodium channel (NavMs), embedded within a lipid bilayer environment. trj_cavity is available for download under an open-source license ( http://sourceforge.net/projects/trjcavity ). A simplified, GROMACS-independent version may also be compiled. PMID:26580540

  18. 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

  19. Beam loading in magnicon deflection cavities

    Energy Technology Data Exchange (ETDEWEB)

    Hafizi, B. [ICARUS Research, Inc., Bethesda, MD (United States); Gold, S.H. [Naval Research Lab., Washington, DC (United States). Plasma Physics Div.

    1997-02-01

    The radio frequency (RF) source for the next linear collider (NLC) is required to generate a power of 1/2--1 GW per tube in a 200-ns pulse, or 100--200 J of energy in a pulse of up to a few {micro}s in duration, at a frequency of 10--20 GHz. A variety of RF sources are under investigation at the present time aimed at fulfilling the needs of the NLC. These include the X-band klystron, Gyroklystron, traveling-wave tube, harmonic convertor, chopper-driven traveling-wave tube, and magnicon. Here, analysis of the beam-deflection cavity interaction in a magnicon is presented and compared with experiment. For a driven cavity a dispersion relation is obtained wherein the interaction modifies the cold-cavity factor and the resonance frequency. In terms of a lumped-parameter equivalent circuit the interaction corresponds to a complex-values beam admittance Y{sub b} in parallel with the cavity admittance. The response of the gain cavities is modified by the same admittance. In a magnicon, Y{sub b} is a sensitive function of the solenoidal focusing magnetic field B{sub 0}, thus providing a convenient means of adjusting the cavity properties in experiments. When the relativistic gyrofrequency is twice the drive frequency, ImY{sub b} = 0 and the beam does not load the cavity. Analytical expressions of the variation of the detuning, instantaneous bandwidth (i.e., loaded quality factor) and gain with B{sub 0} are derived. Simulation results are presented to verify the linear analysis with ideal beams and to illustrate the modifications due to finite beam emittance. Results of the magnicon experiment at the Naval Research Laboratory are examined in the light of the analysis.

  20. Superconducting cavity material for the European XFEL

    Science.gov (United States)

    Singer, W.; Singer, X.; Brinkmann, A.; Iversen, J.; Matheisen, A.; Navitski, A.; Tamashevich, Y.; Michelato, P.; Monaco, L.

    2015-08-01

    Analysis of the strategy for superconducting cavity material procurement and quality management is done on the basis of the experience with the cavity production for the European x-ray free electron laser (EXFEL) facility. An adjustment of the material specification to EXFEL requirements, procurement of material, quality control (QC), documentation, and shipment to cavity producers have been worked out and carried out by DESY. A multistep process of qualification of the material suppliers included detailed material testing, single- and nine-cell cavity fabrication, and cryogenic radiofrequency tests. Production of about 25 000 semi-finished parts of high purity niobium and niobium-titanium alloy in a period of three years has been divided finally between companies Heraeus, Tokyo Denkai, Ningxia OTIC, and PLANSEE. Consideration of large-grain (LG) material as a possible option for the EXFEL has resulted in the production of one cryogenic module consisting of seven (out of eight) LG cavities. LG materials fulfilled the EXFEL requirements and showed even 25% to 30% higher unloaded quality factor. A possible shortage of the required quantity of LG material on the market led, however, to the choice of conventional fine-grain (FG) material. Eddy-current scanning (ECS) has been applied as an additional QC tool for the niobium sheets and contributed significantly to the material qualification and sorting. Two percent of the sheets have been rejected, which potentially could affect up to one-third of the cavities. The main imperfections and defects in the rejected sheets have been analyzed. Samples containing foreign material inclusions have been extracted from the sheets and electrochemically polished. Some inclusions remained even after 150 μm surface layer removal. Indications of foreign material inclusions have been found in the industrially fabricated and treated cavities and a deeper analysis of the defects has been performed.

  1. Nonprobabilistic teleportation of field state via cavity QED

    OpenAIRE

    De Carvalho, Carlos Renato; Guerra, Emerson S.; Jalbert, Ginette; Garreau, Jean Claude

    2007-01-01

    International audience In this article we discuss a teleportation scheme of coherent states of cavity field. The experimental realization proposed makes use of cavity quatum electrodynamics involving the interaction of Rydberg atoms with micromaser and Ramsey cavities. In our scheme the Ramsey cavities and the atoms play the role of auxiliary systems used to teleport the state from a micromaser cavity to another. We show that, even if the correct atomic detection fails in the first trials,...

  2. Availability of tree cavities in a sal forest of Nepal

    OpenAIRE

    Bhusal P; Czeszczewik D; Walankiewicz W; Churski M; Baral R; Lamichhane BR; Mikusinski G

    2016-01-01

    Tree cavities are important structural elements of forest ecosystem that host numerous birds, mammals and other cavity-dependent organisms. Pattern of cavity distribution in temperate and boreal forests are relatively well studied, yet little is known about cavities in tropical and subtropical forests. We compared cavity availability in relation to tree condition (living tree and snag), tree species and DBH class between two different sites in a subtropical deciduous sal forest in Nepal: the ...

  3. Superconducting RF cavity R&D for future accelerators

    OpenAIRE

    Ginsburg, C.M.

    2009-01-01

    High-beta superconducting radiofrequency (SRF) elliptical cavities are being developed for several accelerator projects including Project X, the European XFEL, and the International Linear Collider (ILC). Fermilab has recently established an extensive infrastructure for SRF cavity R&D for future accelerators, including cavity surface processing and testing and cavity assembly into cryomodules. Some highlights of the global effort in SRF R&D toward improving cavity performance, and Fermilab SR...

  4. The main linac cavity for Cornell's energy recovery linac: Cavity design through horizontal cryomodule prototype test

    International Nuclear Information System (INIS)

    Future particle accelerators will require continuous wave operation of SRF cavities capable of supporting high beam currents. An example of this is the Energy Recovery Linac (ERL) at Cornell University, a next generation light source designed to run high currents (100 mA) with a high bunch repetition rate (1.3 GHz). Obtaining the beam emittance necessary to meet design specification requires strong damping of higher-order modes that can lead to beam breakup. We discuss the optimization and verification of the accelerating cavity. Next we show that an ERL constructed from the optimized cavity geometry – including realistic shape errors – can support beam currents in excess of 300 mA while still maintaining beam stability. A niobium prototype 7-cell cavity was fabricated and tested in a horizontal cryomodule. We show that the prototype cavity exceeds quality factor and gradient specifications of 2×1010 at 16.2 MV/m at 1.8 K by 50%, reaching Q=(3.0±0.3)×1010. The prototype cavity also satisfies all design constraints and has a higher order mode spectrum consistent with the optimized shape geometry. At 1.6 K, the cavity set a record for quality factor of a multicell cavity installed in a horizontal cryomodule reaching Q=(6.1±0.6)×1010

  5. ANALYSIS OF THE SLOT HEATING OF THE COUPLED CAVITY LINAC CAVITY

    International Nuclear Information System (INIS)

    CCL cavities are figures of revolution about the beam axis. An automated tuning program sets up the geometry for a symmetric accelerating cavity and runs SUPERFISH [1] repetitively, varying the geometry to tune each cavity to the desired frequency for the electromagnetic fields. SUPERFISH [1] solves Maxwell's equations in 2-D. A large portion of the RF power (60-80%) applied to accelerate protons is a waste heat deposited on the inside of the copper cavity. This waste heat is removed most efficiently with water circulating through cooling passages. The waste heat needs to be removed in order to minimize thermal deformations and with it control the resonance of the cavities. A slot between the main cavity and coupled cavity receives additional heating that is not captured in the 2-D analysis. This heating causes deformation of the region and with it frequency shift. This paper covers the estimation of the slot heating and three-dimensional thermal and structural analysis of the CCL cavity

  6. Transferring of a Two-Mode Entangled State Between Two Cavities via Cavity QED

    Institute of Scientific and Technical Information of China (English)

    WU Tao; NI Zhi-Xiang; YE Liu

    2007-01-01

    We propose a scheme for transferring of a two-mode entanglement of zero- or one-photon entangled states between two cavities via atom-cavity field resonant interaction.In our proposal,in order to transfer the entangled state,we only need two identical two-level atoms and a two-mode cavity for receiving the teleported state.This scheme does not require Bell-state measurement and performing any transformations to reconstruct the initial state.And the transfer can occur with 100% success probability in a simple manner.And a network for transferring of a two-mode entangled state between cavities is suggested.This scheme can also be extended to transfer N-mode entangled state of cavity.

  7. 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.

  8. Dispersive optomechanics: a membrane inside a cavity

    International Nuclear Information System (INIS)

    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 104-105. The imaginary part of the membrane's index of refraction is found to be ∼10-4. 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.

  9. A spherical cavity model for quadrupolar dielectrics.

    Science.gov (United States)

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

    2016-03-21

    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 ε 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. PMID:27004882

  10. Spindle cell carcinoma of the nasal cavity

    Directory of Open Access Journals (Sweden)

    Mark D DeLacure

    2013-02-01

    Full Text Available Spindle cell carcinoma (SpCC is a unique variant of squamous cell carcinoma (SCC. SpCC confined to the nasal cavity is extremely rare, with only one case having been previously reported. We present a case report of nasal cavity SpCC and review the literature on this rare entity. A 29-year-old male presented with intermittent epistaxis from the left nasal cavity. On physical examination, the patient had an ulcerated mass in the left nasal vestibule and a biopsy showed a proliferation of spindle and epitheliod cells. The patient underwent wide local excision of the mass via a lateral alotomy approach and reconstruction with a composite conchal bowl skin and cartilage graft. Histologically, the mass had dyplastic squamous epithelium and spindle-shaped cells admixed with epitheliod cells. Immunohistochemistry was only positive for pancytokeratin AE1/AE3 and vimentin. Six months after surgery, the patient continues to have no evidence of disease. On literature review, only one previous case of SpCC confined to the nasal cavity was identified. We present a rare case of nasal cavity SpCC. No definite treatment protocol exists for this unique entity, but we believe that this tumor should primarily be treated with aggressive, wide local excision. Adjuvant radiation and/or chemotherapy have also been used anecdotally.

  11. 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...

  12. DISCHARGING MASTOID CAVITY: A CLINICAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    Praveen Kumar

    2015-05-01

    Full Text Available CONTEXT: A discharging mastoid cavity is a frustrating condition for both patient and surgeon and can occur after a canal wall down mastoidectomy operation . AIMS: To determine the percentage of patients having a discharging mastoid cavity and to establish the aetiological factors responsible for it . SETTING: Academic tertiary care referral institution . DESIGN: Prospective study MATERIALS AND METHODS: One hundred and sixty nine patie nts with chronic suppurative otitis media with cholesteatoma who underwent a canal wall down mastoidectomy were included in the study . These patients were regularly followed up to detect the occurrence of discharging mastoid cavity . RESULTS: Forty one ( 24 . 26% patients had a discharging mastoid cavity after a mean follow up of 4 . 2 years . The main causes were tympanic membrane perforation with exposed middle ear mucosa and open eustachian tube in thirty two patients ( 78 . 04% , followed by meatal stenosis in twenty five patients ( 60 . 97% and high facial ridge in twenty patients ( 48 . 78% . CONCLUSIONS: Tympanic membrane perforation with exposure of middle ear mucosa , meatal stenosis and a high facial ridge are important causes for a discharging mastoid cavity .

  13. Unifying Brillouin scattering and cavity optomechanics

    Science.gov (United States)

    Van Laer, Raphaël; Baets, Roel; Van Thourhout, Dries

    2016-05-01

    So far, Brillouin scattering and cavity optomechanics have been mostly disconnected branches of research, although both deal with photon-phonon coupling. This begs for the development of a broader theory that contains both fields. Here, we derive the dynamics of optomechanical cavities from that of Brillouin-active waveguides. This explicit transition elucidates the link between phenomena such as Brillouin amplification and electromagnetically induced transparency. It proves that effects familiar from cavity optomechanics all have traveling-wave partners, but not vice versa. We reveal a close connection between two parameters of central importance in these fields: the Brillouin gain coefficient and the zero-point optomechanical coupling rate. This enables comparisons between systems as diverse as ultracold atom clouds, plasmonic Raman cavities, and nanoscale silicon waveguides. In addition, back-of-the-envelope calculations show that unobserved effects, such as photon-assisted amplification of traveling phonons, are now accessible in existing systems. Finally, we formulate both circuit- and cavity-oriented optomechanics in terms of vacuum coupling rates, cooperativities, and gain coefficients, thus reflecting the similarities in the underlying physics.

  14. Tooth structure and fracture strength of cavities

    DEFF Research Database (Denmark)

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

    2007-01-01

    (Groups I, II and III) and indirect inlay cavities (Groups IV, V and VI) were prepared maintaining standardized dimensions: 2-mm deep pulpal floors, 1.5-mm wide gingival walls and 2-mm high axial walls. Buccolingual width of the occlusal box was established at 1/4 (Groups I and IV), 1/3 (Groups II and V...... 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...... mass loss (13.91%) than composite resin preparations with the same width (10.02%). 1/2-inlay cavities had 21.34% of mass loss versus 16.19% for the 1/2-composite resin cavities. Fracture strength means (in kgf) were: GI = 187.65; GII = 143.62; GIII = 74.10; GIV = 164.22; GV = 101.92; GVI = 50...

  15. CT findings of malignant nasal cavity tumors

    International Nuclear Information System (INIS)

    To evaluate the CT findings of malignant nasal cavity tumors. Retrospective analysis was performed on 20 patients with pathologically-proven malignant nasal cavity tumors. Using CT, we analysed their location, extent of bone destruction and of involvement of adjacent structures, and enhancing pattern. A total of 20 cases included nine squamous cell carcinomas, three olfactory neuroblastomas, three lymphomas, two polymorphic reticulosis, one adenoid cystic carcinoma, one undifferentiated carcinoma and one metastasis from renal cell carcinoma. All cases except one adenoid cystic carcinoma and one squamous cell carcinoma revealed bone destruction or erosion. Aggressive bone destruction and irregular enhancement were seen in eight cases of squamous cell carcinoma, seven cases of which showed involvement of the adjacent paranasal sinuses, nasopharynx, and orbit. Olfactory neuroblastomas were centered in the superior nasal cavity and the adjacent ethmoid sinus, and erosion or destruction of the cribriform plate had occurred. Lymphomas showed bilateral involvement, with uniform contrast enhancement. Polymorphic reticuloses showed perforation or erosion of the nasal septum, with bilateral involvement of the nasal cavity. The location, presence of bone destruction, involvement of adjacent structures, and enhancement pattern of tumor on CT can be helpful for the differential diagnosis of malignant nasal cavity tumors

  16. Observing different quantum trajectories in cavity QED

    CERN Document Server

    Santos, Marcelo França

    2011-01-01

    The experimental observation of quantum jumps is an example of single open quantum systems that, when monitored, evolve in terms of stochastic trajectories conditioned on measurements results. Here we present a proposal that allows the experimental observation of a much larger class of quantum trajectories in cavity QED systems. In particular, our scheme allows for the monitoring of engineered thermal baths that are crucial for recent proposals for probing entanglement decay and also for entanglement protection. The scheme relies on the interaction of a three-level atom and a cavity mode that interchangeably play the roles of system and probe. If the atom is detected the evolution of the cavity fields follows quantum trajectories and vice-versa.

  17. Dynamically Reconfigurable Photonic Crystal Nanobeam Cavities

    CERN Document Server

    Frank, Ian W; McCutcheon, Murray W; Loncar, Marko

    2009-01-01

    Wavelength-scale, high Q-factor photonic crystal cavities have emerged as a platform of choice for on-chip manipulation of optical signals, with applications ranging from low-power optical signal processing and cavity quantum electrodynamics, to biochemical sensing. Many of these applications, however, are limited by the fabrication tolerances and the inability to precisely control the resonant wavelength of fabricated structures. Various techniques for post-fabrication wavelength trimming and dynamical wavelength control -- using, for example, thermal effects, free carrier injection, low temperature gas condensation, and immersion in fluids -- have been explored. However, these methods are often limited by small tuning ranges, high power consumption, or the inability to tune continuously or reversibly. In this letter, by combining nano-electro-mechanical systems (NEMS) and nanophotonics, we demonstrate reconfigurable photonic crystal nanobeam cavities that can be continuously and dynamically tuned using elec...

  18. CEBAF cavity fabrication - a successful technology transfer

    International Nuclear Information System (INIS)

    Babcock ampersand Wilcox (B ampersand W) has successfully completed an R.F. accelerator technology transfer with Cornell University for CEBAF, the Continuous Electron Beam Accelerator Facility. With this transfer of technology, B ampersand W has commercially fabricated four niobium LE-5 R.F. cavities, 12 niobium spool pieces, and 12 niobium adaptors for CEBAF. The fourth niobium cavity was warm tuned to specification at the B ampersand W test facility. The industrialization of the accelerator technology benefits the scientific community because industry can provide large scale production resources, including standardized procedures, processes, and specifications, to assist in the construction of accelerator/collider projects. B ampersand W has taken laboratory technology and developed standardized industrial procedures and processes for the fabrication of the CEBAF/Cornell R.F. cavity. B ampersand W's industrialization of accelerator technology is discussed herein. 5 refs., 1 fig

  19. Plasmonic coaxial waveguide-cavity devices.

    Science.gov (United States)

    Mahigir, Amirreza; Dastmalchi, Pouya; Shin, Wonseok; Fan, Shanhui; Veronis, Georgios

    2015-08-10

    We theoretically investigate three-dimensional plasmonic waveguide-cavity structures, built by side-coupling stub resonators that consist of plasmonic coaxial waveguides of finite length, to a plasmonic coaxial waveguide. The resonators are terminated either in a short or an open circuit. We show that the properties of these waveguide-cavity systems can be accurately described using a single-mode scattering matrix theory. We also show that, with proper choice of their design parameters, three-dimensional plasmonic coaxial waveguide-cavity devices and two-dimensional metal-dielectric-metal devices can have nearly identical transmission spectra. Thus, three-dimensional plasmonic coaxial waveguides offer a platform for practical implementation of two-dimensional metal-dielectric-metal device designs. PMID:26367907

  20. Nitrogen doping study in ingot niobium cavities

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-01

    Thermal diffusion of nitrogen in niobium superconducting radio frequency cavities at temperature ~800 °C has resulted in the increase in quality factor with a low-field Q-rise extending to Bp > 90 mT. However, the maximum accelerating gradient of these doped cavities often deteriorates below the values achieved by standard treatments prior to doping. Here, we present the results of the measurements on ingot niobium cavities doped with nitrogen at 800 °C. The rf measurements were carried out after the successive electropolishing to remove small amount of material from the inner surface layer. The result showed higher breakdown field with lower quality factor as material removal increases.

  1. Minimum wakefield achievable by waveguide damped cavity

    International Nuclear Information System (INIS)

    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

  2. Enhancements to cavity quantum electrodynamics system

    CERN Document Server

    Cimmarusti, A D; Norris, D G; Orozco, L A

    2011-01-01

    We show the planned upgrade of a cavity QED experimental apparatus. The system consists of an optical cavity and an ensemble of ultracold $^{85}$Rb atoms coupled to its mode. We propose enhancements to both. First, we document the building process for a new cavity, with a planned finesse of $\\sim$20000. We address problems of maintaining mirror integrity during mounting and improving vibration isolation. Second, we propose improvements to the cold atom source in order to achieve better optical pumping and control over the flux of atoms. We consider a 2-D optical molasses for atomic beam deflection, and show computer simulation results for evaluating the design. We also examine the possibility of all-optical atomic beam focusing, but find that it requires unreasonable experimental parameters.

  3. Observing spin optodynamical analog of cavity optomechanics

    Science.gov (United States)

    Gerber, Justin; Kohler, Jonathan; Spethmann, Nicolas; Schreppler, Sydney; Stamper-Kurn, Dan

    2016-05-01

    Cavity Optomechanics has been realized in many diverse systems and led to many interesting results such as ponderomotive squeezing of light, beyond-SQL measurement sensitivity, and squeezing of mechanical oscillators. Optical cavities also allow sensitive measurements of the spin of an atomic ensemble. It has been proposed to utilize this sensitivity to realize an analog of optomechanics by measuring the precession of small excitations of a spin-oscillator around a transverse magnetic field. I will present our recent work in which we realize optomechanical analogs in our system such as cavity-assisted cooling and amplification and optical spring shifts. In addition, the presence of a high-energy `ground state' of the spin oscillator allows the realization of an effective negative mass oscillator which is demonstrated by an inverted sideband asymmetry. In our ongoing work we attempt to realize coherent quantum noise cancelation by coupling spin oscillation with mechanical oscillation.

  4. High brightness angled cavity quantum cascade lasers

    International Nuclear Information System (INIS)

    A quantum cascade laser (QCL) with an output power of 203 W is demonstrated in pulsed mode at 283 K with an angled cavity. The device has a ridge width of 300 μm, a cavity length of 5.8 mm, and a tilt angle of 12°. The back facet is high reflection coated, and the front facet is anti-reflection coated. The emitting wavelength is around 4.8 μm. In distinct contrast to a straight cavity broad area QCL, the lateral far field is single lobed with a divergence angle of only 3°. An ultrahigh brightness value of 156 MW cm−2 sr−1 is obtained, which marks the brightest QCL to date

  5. Beam cavity interaction computer code for linacs

    International Nuclear Information System (INIS)

    A computer code BCI was used to calculate the energy loss of beam bunches in two types of cavities being studied in ORNL. The merit of the proposed on-axis coupled structure for CHEER is discussed in terms of beam energy loss. A calculation for a simple structure consisting of two accelerating cells and a coupling cell is performed. The amplitude modulation of the wake field is interpreted as the excitation of the zero and π coupled-resonator modes and coupling coefficients are derived. Beam loading of a cw linear accelerator is studied by calculating the bunch energy loss and cavity energy when a cavity is excited resonantly with a series of beam bunches. Calculations of non-resonant excitation are also presented

  6. Cryogenic system for TRISTAN superconducting RF cavity

    International Nuclear Information System (INIS)

    Superconducting RF cavities will be installed in TRISTAN at KEK to upgrade the electron-positron beam energy to 33 GeV x 33 GeV. Two 5-cell cavities are coupled together, enclosed in a cryostat, and cooled by liquid helium pool boiling. The cryogenic system for the cavities is described and a system flow diagram constructed. Heat loads are estimated and component specifications are given. The capacity of the helium refrigerator is 4 kW at 4.4 K with liquid nitrogen precooling and two expansion turbines. The system is designed to be upgraded to 6.5 kW with added expansion turbines and compressors and the elimination of liquid nitrogen

  7. TM01 mode accelerating cavity optimization

    International Nuclear Information System (INIS)

    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 (TM01 mode) relative to the maximum effective shunt impedance ZT2 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 (TM02 mode) for the disk and washer structure

  8. Crab cavity for the B-factories

    International Nuclear Information System (INIS)

    In order to realize the crab crossing scheme desired for B-factories, we have designed single cell superconducting crab cavities operating in TMI 10 mode. A coaxial beam pipe was attached to damp dangerous monopole and dipole parasitic modes. We designed two kinds of cell shape depending on the method to cure the unwanted polarization of TMI 10 mode; one is a round cell which will be slightly polarized and the other is an extremely polarized (squashed) cell. Necessary kick voltage can be obtained with the present technology of superconducting cavities. We have measured the coaxial beam pipe and a squashed crab cavity of one-third scale copper/aluminum model. The Q of all the dangerous monopole and dipole modes are damped to less than the order of 100, as was expected by calculations. High Q of the crabbing mode is also assured with a notch filter

  9. Cover slip external cavity diode laser

    CERN Document Server

    Carr, Adra V; Waitukaitis, Scott R; Perreault, John D; Lonij, Vincent P A; Cronin, Alexander D

    2007-01-01

    The design of a 671 nm diode laser with a mode-hop-free tuning range of 40 GHz is described. This long tuning range is achieved by simultaneously ramping the external cavity length with the laser injection current. The external cavity consists of a microscope cover slip mounted on piezoelectric actuators. In such a configuration the laser output pointing remains fixed, independent of its frequency. Using a diode with an output power of 5-7 mW, the laser linewidth was found to be smaller than 30 MHz. This cover slip cavity and feedforward laser current control system is simple, economical, robust, and easy to use for spectroscopy, as we demonstrate with lithium vapor and lithium atom beam experiments.

  10. High brightness angled cavity quantum cascade lasers

    Energy Technology Data Exchange (ETDEWEB)

    Heydari, D.; Bai, Y.; Bandyopadhyay, N.; Slivken, S.; Razeghi, M., E-mail: razeghi@eecs.northwestern.edu [Center for Quantum Devices, Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois 60208 (United States)

    2015-03-02

    A quantum cascade laser (QCL) with an output power of 203 W is demonstrated in pulsed mode at 283 K with an angled cavity. The device has a ridge width of 300 μm, a cavity length of 5.8 mm, and a tilt angle of 12°. The back facet is high reflection coated, and the front facet is anti-reflection coated. The emitting wavelength is around 4.8 μm. In distinct contrast to a straight cavity broad area QCL, the lateral far field is single lobed with a divergence angle of only 3°. An ultrahigh brightness value of 156 MW cm{sup −2 }sr{sup −1} is obtained, which marks the brightest QCL to date.

  11. Coaxial cavity vircator with enhanced efficiency

    Science.gov (United States)

    Liu, G. Z.; Shao, H.; Yang, Z. F.; Song, Z. M.; Chen, C. H.; Sun, J.; Zhang, Y. P.

    2008-04-01

    A vircator with a coaxial cavity has the potential to increase the beam-microwave conversion efficiency. According to the E-field distribution pattern of the modes in the anode cavity of a coaxial vircator, the resonant frequency band of the injected electron beam and the lowest two operating modes are derived. The main frequency of the virtual cathode is also deduced. The optimal operating frequency and high-efficiency designing method of a coaxial cavity vircator is discussed. An experimental setup is designed and built to test the high-power microwave (HPM) generation mechanism described by theoretical analysis as well as increase the power efficiency. HPM frequency obtained in the experiment is in good agreement with the analysis. The power and energy efficiencies obtained in the experiment are, respectively, 8.7% and 6.8% with 50 ns pulse width. Frequency and phase stable HPM radiation is observed as well as pulse shortening is evidently depressed.

  12. Prominence mass supply and the cavity

    International Nuclear Information System (INIS)

    A prevalent but untested paradigm is often used to describe the prominence-cavity system: the cavity is under-dense because it is 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 evolution of the prominence and the surrounding corona. We examine the evidence for a prominence-cavity connection by comparing the TNE model with diagnostics of dynamic extreme ultraviolet (EUV) emission surrounding the prominence, specifically prominence horns. Horns are correlated extensions of prominence 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 Å bandpass near the 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 our 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.

  13. Electrostatically tunable optomechanical "zipper" cavity laser

    CERN Document Server

    Perahia, Raviv; Meenehan, Sean; Alegre, Thiago P Mayer; Painter, Oskar

    2010-01-01

    A tunable nanoscale "zipper" laser cavity, formed from two doubly clamped photonic crystal nanobeams, is demonstrated. Pulsed, room temperature, optically pumped lasing action at a wavelength of 1.3 micron is observed for cavities formed in a thin membrane containing InAsP/GaInAsP quantum-wells. Metal electrodes are deposited on the ends of the nanobeams to allow for micro-electro-mechanical actuation. Electrostatic tuning and modulation of the laser wavelength is demonstrated at a rate of 0.25nm/V^2 and a frequency as high as 6.7MHz, respectively.

  14. Progress in diagnostic techniques for sc cavities

    International Nuclear Information System (INIS)

    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

  15. 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.

  16. Optical cavity resonator in an expanding universe

    Science.gov (United States)

    Kopeikin, Sergei M.

    2015-02-01

    We study the cosmological evolution of frequency of a standing electromagnetic wave in a resonant optical cavity placed to the expanding manifold described by the Robertson-Walker metric. Because of the Einstein principle of equivalence (EEP), one can find a local coordinate system (a local freely falling frame), in which spacetime is locally Minkowskian. However, due to the conformal nature of the Robertson-Walker metric the conventional transformation to the local inertial coordinates introduces ambiguity in the physical interpretation of the local time coordinate, . Therefore, contrary to a common-sense expectation, a straightforward implementation of EEP alone does not allow us to unambiguously decide whether atomic clocks based on quantum transitions of atoms, ticks at the same rate as the clocks based on electromagnetic modes of a cavity. To resolve this ambiguity we have to analyse the cavity rigidity and the oscillation of its electromagnetic modes in an expanding universe by employing the full machinery of the Maxwell equations irrespectively of the underlying theory of gravity. We proceed in this way and found out that the size of the cavity and the electromagnetic frequency experience an adiabatic drift in conformal (unphysical) coordinates as the universe expands in accordance with the Hubble law. We set up the oscillation equation for the resonant electromagnetic modes, solve it by the WKB approximation, and reduce the coordinate-dependent quantities to their counterparts measured by a local observer who counts time with atomic clock. The solution shows that there is a perfect mutual cancellation of the adiabatic drift of cavity's frequency by space transformation to local coordinates and the time counted by the clocks based on electromagnetic modes of cavity has the same rate as that of atomic clocks. We conclude that if general relativity is correct and the local expansion of space is isotropic there should be no cosmological drift of frequency of a

  17. Fundamental Research in Superconducting RF Cavity Design

    Energy Technology Data Exchange (ETDEWEB)

    Georg Hoffstaetter

    2012-11-13

    This is a 3-year SRF R&D proposal with two main goals: 1) to benefit near term high gradient SRF applications by understanding the causes of quench at high fields in present-day niobium cavities 2) to open the long-range prospects for SRF applications by experimentally verifying the recent exciting theoretical predication for new cavity materials such as Nb3Sn and MgB2. These predictions shwo that ultimately gradients of 100Mv/m to 200MV/m may become possible as material imperfections are overcome.

  18. Cavity-induced quantum cooperative phenomena

    Science.gov (United States)

    Plastina, F.; Falcone, G.; Francica, F.; Liberti, G.; Piperno, F.; Maniscalco, S.

    2010-09-01

    Two kinds of cooperative effects are discussed for two-level atoms (qubits) interacting with an electromagnetic resonator, both of them concerning Dicke super-radiance. The first is a static, critical phenomenon: the so-called super-radiant phase transition, occurring when a large number of qubits are coupled to a single cavity mode giving rise to a quantum phase transition for a critical value of the interaction strength. The second is a dynamic phenomenon, producing (among other effects) the generation and/or preservation of entanglement between qubits even in the presence of cavity losses.

  19. Cavity-induced quantum cooperative phenomena

    International Nuclear Information System (INIS)

    Two kinds of cooperative effects are discussed for two-level atoms (qubits) interacting with an electromagnetic resonator, both of them concerning Dicke super-radiance. The first is a static, critical phenomenon: the so-called super-radiant phase transition, occurring when a large number of qubits are coupled to a single cavity mode giving rise to a quantum phase transition for a critical value of the interaction strength. The second is a dynamic phenomenon, producing (among other effects) the generation and/or preservation of entanglement between qubits even in the presence of cavity losses.

  20. BNl 703 MHz superconducting RF cavity testing

    International Nuclear Information System (INIS)

    The BNL 5-cell, 703 MHz superconducting accelerating cavity has been installed in the high-current ERL experiment. This experiment will function as a proving ground for the development of high-current machines in general and is particularly targeted at beam development for an electron-ion collider (eRHIC). The cavity performed well in vertical tests, demonstrating gradients of 20 MV/m and a Q0 of 1e10. Here we will present its performance in the horizontal tests, and discuss technical issues involved in its implementation in the ERL.

  1. 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

  2. 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

  3. 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.

  4. Accelerating RF cavity of the Booster

    CERN Multimedia

    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.

  5. Effective mode volumes for leaky optical cavities

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst; Van Vlack, Cole; Hughes, Stephen

    2011-01-01

    definition of an effective mode volume is ambiguous and not applicable. Instead, we propose an alternative effective mode volume which can be easily evaluated based on the mode calculation methods typically applied in the literature and which is directly applicable to a much wider range of physical systems.......We show that for optical cavities with any finite dissipation, the term “cavity mode” should be understood as a solution to the Helmholtz equation with outgoing wave boundary conditions. This choice of boundary condition renders the problem non-Hermitian, and we demonstrate that the common...

  6. Availability of tree cavities in a sal forest of Nepal

    Directory of Open Access Journals (Sweden)

    Bhusal P

    2016-04-01

    Full Text Available Tree cavities are important structural elements of forest ecosystem that host numerous birds, mammals and other cavity-dependent organisms. Pattern of cavity distribution in temperate and boreal forests are relatively well studied, yet little is known about cavities in tropical and subtropical forests. We compared cavity availability in relation to tree condition (living tree and snag, tree species and DBH class between two different sites in a subtropical deciduous sal forest in Nepal: the Chitwan National Park Forest (the park site and the Khorsor Buffer Zone Forest (the buffer site. Surveys for tree cavities were conducted in 2013 on 50 circular sample plots of size 0.1 ha. We recorded 40 cavity trees in the park site and 31 cavity trees in the buffer site. Density of cavities was on average 22.4 ha-1 in the park site and 19.2 ha-1 in the buffer site. Cavities occurred mostly in living trees (85.9% cavity trees and were formed mostly by damage and decay (natural cavities: 74% or by woodpecker activity (excavated cavities: 26%. Most were observed on three tree species: Shorea robusta, Dillenia pentagyna and Syzygium operculatum, with a mean diameter of 43 cm (range: 12-111 cm. S. operculatum, Myrsine semiserrata and Semecarpus anacardium were overrepresented among tree species with cavities. In snags, 25.0% of all cavities were found in the park site and 8.3% in the buffer site, while snags represented 4.2% and 2.2% of all trees in the two sites, respectively. Statistical anaysis indicated that tree species, tree condition and particularly diameter (DBH were important variables for the prediction of cavity presence. We recommend cavity-bearing tree species to be better protected by forest management in order to help maintain the community of cavity dwellers.

  7. Nonprobabilistic teleportation of field state via cavity QED

    CERN Document Server

    De Carvalho, C R; Jalbert, G; Garreau, J C; Carvalho, Carlos Renato De; Guerra, Emerson S.; Jalbert, Ginette; Garreau, Jean Claude

    2007-01-01

    In this article we discuss a teleportation scheme of coherent states of cavity field. The experimental realization proposed makes use of cavity quatum electrodynamics involving the interaction of Rydberg atoms with micromaser and Ramsey cavities. In our scheme the Ramsey cavities and the atoms play the role of auxiliary systems used to teleport the state from a micromaser cavity to another. We show that, even if the correct atomic detection fails in the first trials, one can succeed in teleportating the cavity field state if the proper measurement occurs in a later atom.

  8. 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.

  9. Nonprobabilistic teleportation of a field state via cavity QED

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, C R [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cx. Postal 68528, 21941-972 Rio de Janeiro, RJ (Brazil); Guerra, E S [Departamento de Fisica, Universidade Federal Rural do Rio de Janeiro, Cx. Postal 23851, 23890-000 Seropedica, RJ (Brazil); Jalbert, Ginette [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cx. Postal 68528, 21941-972 Rio de Janeiro, RJ (Brazil); Garreau, J C [Laboratoire de Physique des Lasers, Atomes et Molecules, Universite des Sciences et Technologies de Lille, Bat. P5, F-59650 Villeneuve d' Ascq Cedex (France)

    2007-03-28

    In this paper, we discuss a teleportation scheme of coherent states of a cavity field. The experimental realization proposed makes use of cavity quantum electrodynamics, involving the interaction of Rydberg atoms with micromaser and Ramsey cavities. In our scheme the Ramsey cavities and the atoms play the role of auxiliary systems used to teleport the state from one micromaser cavity to another. We show that, even if the correct atomic detection fails in the first trials, one can succeed in teleportating the cavity field state if proper measurement occurs in a later atom.

  10. Controlled coupling of photonic crystal cavities using photochromic tuning

    CERN Document Server

    Cai, Tao; Solomon, Glenn S; Waks, Edo

    2013-01-01

    We present a method to control the resonant coupling interaction in a coupled-cavity photonic crystal molecule by using a local and reversible photochromic tuning technique. We demonstrate the ability to tune both a two-cavity and a three-cavity photonic crystal molecule through the resonance condition by selectively tuning the individual cavities. Using this technique, we can quantitatively determine important parameters of the coupled-cavity system such as the photon tunneling rate. This method can be scaled to photonic crystal molecules with larger numbers of cavities, which provides a versatile method for studying strong interactions in coupled resonator arrays.

  11. Observation of dressed intra-cavity dark states

    OpenAIRE

    Wang, Yanhua; Zhang, Jiepeng; Zhu, Yifu

    2011-01-01

    Cavity electromagnetically induced transparency in a coherently prepared cavity-atom system is manifested as a narrow transmission peak of a weak probe laser coupled into the cavity mode. We show that with a resonant pump laser coupling the cavity-confined four-level atoms from free space, the narrow transmission peak of the cavity EIT is split into two peaks. The two peaks represent the dressed intra-cavity dark states and have a frequency separation approximately equal to the Rabi frequency...

  12. 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.......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....

  13. Efficient generation of Bell-cat states in remote cavities

    Institute of Scientific and Technical Information of China (English)

    LI Xing; ZHANG Ying-Jie; XIA Yun-Jie

    2008-01-01

    In the context of cavity quantum electrodynamics (QED), a potential scheme is proposed to generate entangled coherentstates. The scheme includes twice interactions of two-level atoms with cavities. In the first interaction, two atoms are sentinto a microwave cavity with the large detuning respectively. And then the second interaction is that the two atoms enteranother microwave cavity and are driven by a resonant classical field meantime. When we choose the proper interactiontime and make measurement on the two atoms, the two microwave cavity mode fields are determinatively entangled. Inaddition, it is easy to generalize the scheme to multi-cavity and multi-atom.

  14. Preparation of Macroscopic Quantum Superposition States of Cavity Modes Using rf-SQUIDs in a Cavity

    Institute of Scientific and Technical Information of China (English)

    WANG Bo

    2008-01-01

    We propose a potential scheme of preparing Schrodinger-cat state of the cavity mode by placing an rf-superconducting quantum interference device (rf-SQUID) in a single-mode microwave cavity. By properly adjusting the detuning and the strength regarding the radiation fields, we show how to generate single-mode Schrodinger-eat state. Generalizing this method we discuss the generation of the engtangled coherent states. The experimental feasibility of our scheme is discussed under consideration of the cavity decay.

  15. Imaging the treated oral cavity and oropharynx

    International Nuclear Information System (INIS)

    Cross-sectional imaging has become essential in the evaluation of the treated oral cavity and oropharynx. The purpose of this paper is to review the imaging guidelines for the evaluation of this region and to detail the typical changes encountered on imaging following surgical and radiation treatment for cancer

  16. Inflammatory Hyperplasia of the Oral Cavity

    OpenAIRE

    Sudarshan, Ramachandran; Vijayabala, G. Sree; Kumar, KS Prem

    2012-01-01

    Oral inflammatory hyperplasias' are the most common oral abnormalities. It manifests as diverse signs and symptoms. It may occur in any part of the oral cavity. They occur mainly due to reactive stimulus hence these lesions are called reactive hyperplasia. Distinguishing these entities and removal of etiological factors are essential. This review illustrates the various hyperplasia of the oral mucosa. Anahtar Kelimeler:

  17. Natural convection inside an irregular porous cavity

    International Nuclear Information System (INIS)

    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)

  18. Congenital malformation of inner ear, single cavity

    International Nuclear Information System (INIS)

    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.

  19. Optical cavity resonator in an expanding universe

    CERN Document Server

    Kopeikin, Sergei

    2014-01-01

    We study evolution of frequency of a standing electromagnetic (EM) wave in a resonant optical cavity placed to the expanding manifold described by the Robertson-Walker metric. One builds a local coordinate system in which spacetime is locally Minkowskian. However, due to the conformal nature of the Robertson-Walker metric the conventional transformation to the local inertial coordinates introduces ambiguity in the physical interpretation of the local time coordinate. Therefore, contrary to a common-sense expectation, a straightforward implementation of EEP alone does not allow us to decide whether atomic clocks ticks at the same rate as the clocks based on EM modes of a cavity. To resolve the ambiguity we analyzed the cavity rigidity and the oscillation of its EM modes in an expanding universe by employing the Maxwell equations. We found out that both the size of the cavity and the EM frequency experience an adiabatic drift in conformal coordinates as the universe expands. We set up the oscillation equation f...

  20. Superconducting Cavities for the APT Accelerator

    Science.gov (United States)

    Krawczyk, Frank L.; Gentzlinger, Robert C.; Montoya, Debbie I.; Rusnak, Brian; Shapiro, Alan H.

    1997-05-01

    One type of design for an Accelerator Production of Tritium (APT) facility being investigated at LANL consists mainly of a linear accelerator using superconducting rf cavities for the acceleration of a high current cw proton beam. For electron accelerators with particles moving at almost the speed of light (β=1.0), resonators with a rounded shape, consisting of elliptical, circular and straight sections, are well established. They are referred to as ``elliptical'' cavities. For the APT-design, this shape has been adapted for much slower proton beams from a β of less than 0.64 to slightly above 0.82. This is a new energy range, in which resonators of an elliptical type have never been used before. Simulations with the well-proven electromagnetic modeling tools MAFIA and SUPERFISH were performed. The structures have been optimized for their rf properties as well as for beam dynamics requirements. Single cell test cavities are under construction and will be tested in our structures laboratory. Their performance in terms of obtainable gradients, Q and multipacting behavior, as well as a comparison of the major rf parameters with the results of the cavity simulations, will be reported.

  1. Thermal infrared detection of cavities in trees

    International Nuclear Information System (INIS)

    The authors present a Remote Sensing System for detecting internal cavities in trees, using a thermal infrared apparatus which combines the benefit of instant data with the additional advantages of not requiring scaffolding or crews and (above all) of not entailing any injury or damage to the tree

  2. Circuit model for cavity with a port

    International Nuclear Information System (INIS)

    These notes present, by way of an example, the calculation of lumped circuit elements to model a cavity that is connected to a transmission line through a coupling loop. This example is featured in a well-known text. It is adopted here to illustrate the concept and the procedures involved in the calculation of equivalent circuit elements. Its generalization is indicated. (author)

  3. Hybrid ion chains inside an optical cavity

    Science.gov (United States)

    Zhou, Zichao; Siverns, James; Quraishi, Qudsia

    2016-05-01

    Trapped ions remain a leading candidate for the implementation of large-scale quantum networks. These networks require nodes that can store and process quantum information as well as communicate with each other though photonic flying qubits. We propose to use hybrid ion chains of barium, for communication, and ytterbium, for quantum information processing. We report on progress in setting up a hybrid ion chain in a versatile four-blade trap using high numerical aperture collection optics. Although the visible photons produced from barium ions are more favorable as they are not suitable for long distance fiber communication. With this in mind, we intend to implement frequency conversion to overcome this issue. Also, with the view toward increasing the flying-qubit production rate, we propose a cavity-based system to enhance interactions between the ions and photons. The cavity axis is to be placed along the axial direction of the trap allowing a chain of multiple ions to interact with the cavity at the same time. With this configuration the atom-photon coupling strength can be improved by sqrt(N), where N is the number of ions. Experiments will focus on exploring the dynamics of hybrid ion chain, dual species quantum information processing, two-colour entanglement and phase gates assisted by the ion-cavity coupling are to be explored.

  4. Microwave Reentrant Cavities for Quantum Devices

    Science.gov (United States)

    Carvalho, Natalia C.; Bourhill, Jeremy; Creedon, Daniel; Goryachev, Maxim; Galliou, Serge; Tobar, Michael

    A microwave reentrant cavity is a device able to provide a very sensitive high-Q microwave mode. Its design can be highly advantageous for electromechanical devices and quantum measurements. In this sense, a tuneable device based on a narrow-gap superconducting reentrant cavity is under development. The resonant frequency is able to be fine-tuned over a range larger than 500 MHz at 10 mK with an electrical Q-factor of 105. Such a cavity could possibly accommodate a transmon qubit to control and manipulate its quantum state. We are also working on the investigation of bulk acoustic wave (BAW) resonators in microwave reentrant cavities. BAW resonators offer a promising way to process quantum information through the coupling between microwaves and acoustic phonons. Thus, we are developing a device able to excite phonons through non-linearities and the piezoelectricity of the plano-convex quartz crystal. We will detail our experiments that work towards cooling gram scale phonon resonances to the quantum ground state. Funded by ARC Grant No. CE110001013 (Australia) and National Counsel of Technological and Scientific Development (Brazil).

  5. 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...

  6. Pressure equalisation of brick masonry cavity walls

    NARCIS (Netherlands)

    Geurts, C.P.W.; Bouma, P.W.; Aghaei, A.

    2005-01-01

    This paper describes two full-scale experiments in which the pressure distribution over the layers of brick masonry cavity walls is studied. The first experiment focuses on the specification of the wind loads on both outer and inner leafs of these walls. The second experiment is set-up to find a mod

  7. 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.

  8. Rf field emission in superconducting cavities

    International Nuclear Information System (INIS)

    Field emission is the most serious problem faced today to achieve higher gradients in superconducting accelerator cavities. Both multipacting and thermal breakdown, which used to be dominant problems of the past are well understood and under control in accelerating cavities designed for velocity of light particles. Experience at CERN, Cornell, DESY, KEK and Wuppertal show that FE is now the usual mechanism limiting achievable accelerating fields for single and multi-cell structures. Peak surface electric fields between 12 and 30 Mv/m and peak surface magnetic fields between 200 and 600 Oersted are achieved in full scale structures corresponding to accelerating gradients between 5 and 12 MeV/m. In single cell cavities peak surface electric fields up to 60 Mv/m and magnetic fields up to 1050 Oe have been achieved. When compared with the 200 Mv/m dc surface fields achieved with cm2 size, clean, heat-treated Nb surfaces, and with the 2400 Oe theoretical rf critical magnetic field capability of Nb it is clear that there remains much room for improvement with Nb cavities. Results with 3000 Mhz heat treated cavities have shown that overall FE loading is less after heat treatment and high fields can be reached more frequently. To improve the understanding of FE behavior in rf fields from cold surfaces, a high speed, superfluid He, thermometer based diagnostic system has been completed. Studies indicate that condensed gases play an important role in FE, so that it would be a worthwhile attempt to look for comparable phenomena in dc FE studies. It has also been established that a Nb surface which can withstand a field of 30 Mv/m does not degrade on exposure to dust-free air, so that this avenue is not a rich source of emitters. 11 references, 13 figures, 1 table

  9. Writing and erasing of temporal cavity solitons by direct phase modulation of the cavity driving field

    CERN Document Server

    Jang, Jae K; Murdoch, Stuart G; Coen, Stephane

    2015-01-01

    Temporal cavity solitons (CSs) are persisting pulses of light that can manifest themselves in continuously driven passive resonators, such as macroscopic fiber ring cavities and monolithic microresonators. Experiments so far have demonstrated two techniques for their excitation, yet both possess drawbacks in the form of system complexity or lack of control over soliton positioning. Here we experimentally demonstrate a new CS writing scheme that alleviates these deficiencies. Specifically, we show that temporal CSs can be excited at arbitrary positions through direct phase modulation of the cavity driving field, and that this technique also allows existing CSs to be selectively erased. Our results constitute the first experimental demonstration of temporal cavity soliton excitation via direct phase modulation, as well as their selective erasure (by any means). These advances reduce the complexity of CS excitation and could lead to controlled pulse generation in monolithic microresonators.

  10. Cavity solitons in broad-area vertical-cavity surface-emitting lasers below threshold

    International Nuclear Information System (INIS)

    Cavity solitons are stationary self-organized bright intensity peaks which form over a homogeneous background in the section of broad area radiation beams. They are generated by shining a writing/erasing laser pulse into a nonlinear optical cavity, driven by a holding beam. The ability to control their location and their motion by introducing phase or amplitude gradients in the holding beam makes them interesting as mobile pixels for all-optical processing units. We show the generation of a number of cavity solitons in broad-area vertical cavity semiconductor microresonators electrically pumped above transparency but slightly below threshold. We analyze the switching process in details. The observed spots can be written, erased, and manipulated as independent objects, as predicted by the theoretical model. An especially tailored one is used to simulate the studied phenomena and to compare our simulations to the experimental findings with good agreement

  11. Process for treatment of inside surface of superconducting cavities (cavity resonators)

    International Nuclear Information System (INIS)

    A cavity of an acceleration unit built up from one or more individual resonators is filled to about half way with ceramic grinding bodies and with water, and turned slowly at about 9 rpm. The rotation is maintained for about a week. The inner surface of the cavity is thus smoothed and freed of faults, so that the cavity can be used without difficulty in superconducting operation with improved properties. By this simple process, success is achieved in increasing the practically possible longitudinal field strength for acceleration by at least a factor of 2 or more, i.e. one can save at least half the acceleration units. To remove grinding wear, the cavity is also filled with an acid mixture of about 1 part of HF, 1 part of HNO3 and 6 parts of H3PO4 and cleaned, and the surface is etched. (orig.)

  12. Tunable 2D Photonic Crystal Cavities for Cavity Electro-Optomechanics

    OpenAIRE

    Winger, Martin; Alegre, Thiago P. Mayer; Safavi-Naeini, Amir H.; Painter, Oskar

    2011-01-01

    We present and demonstrate a novel electro-opto-mechanical structure based on a slotted waveguide photonic-crystal cavity, in which electrostatics and optics couple simultaneously to the same "phonon" resonance.

  13. Incompressible Laminar Flow Over a Three-Dimensional Rectangular Cavity

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper investigates unsteady incompressible flow over cavities,Previous research in in compressible cavity-flow has included flow inside and past a 2-dimensional cavity,and flow inside a 3-dimensional cavity,driven by a moving lid.The present research is focused on incompressible flow past a 3-dimensional open shallow cavity.This involves the complex interaction etween the external flow and the re-circulating flow within the cavity.In particular,computation was performed on a 3-dimensonal shallow rectangular cavity with a laminar boundary layer at the cavity and a Reynolds number of 5,000 and 10,000,respectively,A CFD approach,based on the unsteady Navier-Stokes equation for 3-dimensional incompressible flow,was used in the study.Typical results of the computation are presented.Theses results reveal the highly unsteady and complex vortical structures at high Reynolds numbers.

  14. How Are Nasal Cavity and Paranasal Sinus Cancers Staged?

    Science.gov (United States)

    ... by stage How are nasal cavity and paranasal sinus cancers staged? Staging is a process that tells ... cavity or ethmoid sinuses. T categories for maxillary sinus cancer TX: Primary (main) tumor cannot be assessed. ...

  15. MMIC Cavity Oscillator at 50 and 94 GHz (2007040) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An innovative, ultra-low phase-noise, fully integrated single-chip cavity oscillator is proposed. The cavity is built on a standard MMIC process and has a quality...

  16. Treatment Options by Stage (Lip and Oral Cavity Cancer)

    Science.gov (United States)

    ... common treatment for all stages of lip and oral cavity cancer. Surgery may include the following: Wide local excision : Removal ... cancer may have spread from the lip and oral cavity. Plastic surgery : An operation that restores or improves the appearance ...

  17. General Information about Lip and Oral Cavity Cancer

    Science.gov (United States)

    ... common treatment for all stages of lip and oral cavity cancer. Surgery may include the following: Wide local excision : Removal ... cancer may have spread from the lip and oral cavity. Plastic surgery : An operation that restores or improves the appearance ...

  18. Treatment Option Overview (Lip and Oral Cavity Cancer)

    Science.gov (United States)

    ... common treatment for all stages of lip and oral cavity cancer. Surgery may include the following: Wide local excision : Removal ... cancer may have spread from the lip and oral cavity. Plastic surgery : An operation that restores or improves the appearance ...

  19. Treatment Options for Recurrent Lip and Oral Cavity Cancer

    Science.gov (United States)

    ... common treatment for all stages of lip and oral cavity cancer. Surgery may include the following: Wide local excision : Removal ... cancer may have spread from the lip and oral cavity. Plastic surgery : An operation that restores or improves the appearance ...

  20. Detection Of Multilayer Cavities By Employing RC-DTH Air Hammer System And Cavity Auto Scanning Laser System

    Science.gov (United States)

    Luo, Yongjiang; Li, Lijia; Peng, Jianming; Yin, Kun; Li, Peng; Gan, Xin; Zhao, Letao; Su, Wei

    2015-12-01

    The subterranean cavities are seriously threatened to construction and mining safety, and it's important to obtain the exact localization and dimensions of subterranean cavities for the planning of geotechnical and mining activities. Geophysical investigation is an alternative method for cavity detection, but it usually failed for the uncertainly solution of information and data obtained by Geophysical methods. Drilling is considered as the most accurate method for cavity detection. However, the conventional drilling methods can only be used for single cavity detection, and there is no effective solution for multilayer cavities detection have been reported. In this paper, a reverse circulation (RC) down-the-hole (DTH) air hammer system with a special structured drill bit is built and a cavity auto scanning laser system based on laser range finding technique was employed to confirm the localization and dimensions of the cavities. This RC-DTH air hammer system allows drilling through the upper cavities and putting the cavity auto scanning laser system into the cavity area through the central passage of the drill tools to protect the detection system from collapsing of borehole wall. The RC-DTH air hammer system was built, and field tests were conducted in Lanxian County Iron Ore District, which is located in Lv Liang city of Shan Xi province, the northwest of china. Field tests show that employing the RC-DTH air hammer system assisted by the cavity auto scanning laser system is an efficiency method to detect multilayer cavities.

  1. Teleportation of Atomic States via Cavity Quantum Electrodynamics

    CERN Document Server

    Guerra, E S

    2004-01-01

    In this article we discuss a scheme of teleportation of atomic states. The experimental realization proposed makes use of cavity Quatum Electrodynamics involving the interaction of Rydberg atoms with a micromaser cavity prepared in a coherent state. We start presenting a scheme to prepare atomic Bell states via the interaction of atoms with a cavity. In our scheme the cavity and some atoms play the role of auxiliary systems used to achieve the teleportation.

  2. Coupled beam motion in a storage ring with crab cavities

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaobiao [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-11-16

    We studied the coupled beam motion in a storage ring between the transverse and longitudinal directions introduced by crab cavities. Analytic form of the linear decoupling transformation is derived. Also, the equilibrium bunch distribution in an electron storage ring with a crab cavity is given, including contribution to the eigen-emittance induced by the crab cavity. Application to the short pulse generation scheme using crab cavities [1] is considered.

  3. Installation and Commissioning of CYCIAE-100 RF Cavity

    Institute of Scientific and Technical Information of China (English)

    JI; Bin; XING; Jian-sheng; LIU; Geng-shou; YIN; Zhi-guo; ZHANG; Tian-jue; LEI; Yu; FU; Xiao-liang; LI; Peng-zhan; LV; Yin-long; ZHU; Peng-fei; FU; Li-cheng; LIU; Jie; ZHANG; De-zhi; CUI; Bai-yao; DONG; Huan-jun; WANG; Zhen-hui

    2013-01-01

    The RF cavity is used to establish electrical field for the particle acceleration in the cyclotron,the stability of the RF cavity affects the RF system directly.A RF cavity with high quality can reduce thepower consumption of the RF system and make the cooling system simple.A good design is the first step towards RF cavity with high quality.The installation and commissioning are the next important process to achieve an excellent performance.The height of the

  4. Coupled beam motion in a storage ring with crab cavities

    CERN Document Server

    Huang, Xiaobiao

    2015-01-01

    We studied the coupled beam motion in a storage ring between the transverse and longitudinal directions introduced by crab cavities. Analytic form of the linear decoupling transformation is derived. The equilibrium bunch distribution in an electron storage ring with a crab cavity is given, including contribution to the eigen-emittance induced by the crab cavity. Application to the short pulse generation scheme using crab cavities is considered.

  5. Coupled beam motion in a storage ring with crab cavities

    Science.gov (United States)

    Huang, Xiaobiao

    2016-02-01

    We studied the coupled beam motion in a storage ring between the transverse and longitudinal directions introduced by crab cavities. The analytic form of the linear decoupling transformation is derived. The equilibrium bunch distribution in an electron storage ring with a crab cavity is given, including contribution to the eigenemittance induced by the crab cavity. Application to the short pulse generation scheme using crab cavities is considered.

  6. Beam commissioning of KEKB crab cavity RF system

    International Nuclear Information System (INIS)

    KEKB started the first crab crossing operation in February 2007 with two superconducting crab cavities. After four months operation dedicated for machine tuning, physics run with high-current beams resumed in October with the crab crossing. The crab cavities have been working stably for one and a half years. The crab cavity RF system, commissioning process and performance of the crab cavities with high-current beams are presented. (author)

  7. Optical fiber tips functionalized with semiconductor photonic crystal cavities

    OpenAIRE

    Shambat, Gary; Provine, J; Rivoire, Kelley; Sarmiento, Tomas; Harris, James; Vuckovic, Jelena

    2011-01-01

    We demonstrate a simple and rapid epoxy-based method for transferring photonic crystal cavities to the facets of optical fibers. Passive Si cavities were measured via fiber taper coupling as well as direct transmission from the fiber facet. Active quantum dot containing GaAs cavities showed photoluminescence that was collected both in free space and back through the original fiber. Cavities maintain a high quality factor (2000-4000) in both material systems. This new design architecture provi...

  8. Three-qubit Fredkin gate based on cavity quantum electrodynamics

    Institute of Scientific and Technical Information of China (English)

    Shao Xiao-Qiang; Chen Li; Zhang Shou

    2009-01-01

    This paper presents a scheme for implementing a Fredkin gate on three modes of a cavity.The scheme is based on the dispersive atom-cavity interaction.By modulating the cavity frequency and the atomic transition frequency appropriately,it obtains the effective form of nonlinear interaction between photons in the three-mode cavity.This availability is testified via numerical analysis.It also considers both the situations with and without dissipation.

  9. Preparation of the W state via cavity QED

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jin; YE Liu

    2004-01-01

    A scheme for preparation of the tripartite W state via cavity quantum electrodynamics is presented in this paper. And the scheme can be generalized to prepare the n-atom W states. The second part of this paper shows how to prepare n-cavity W states. All cavities involved are initially in the vacuum states, thus the requirement on the quality factor of the cavities is greatly loosened.

  10. 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...

  11. Photonic Band Gap structures: A new approach to accelerator cavities

    Energy Technology Data Exchange (ETDEWEB)

    Kroll, N. [California Univ., San Diego, La Jolla, CA (United States). Dept. of Physics]|[Stanford Linear Accelerator Center, Menlo Park, CA (United States); Smith, D.R.; Schultz, S. [California Univ., San Diego, La Jolla, CA (United States). Dept. of Physics

    1992-12-31

    We introduce a new accelerator cavity design based on Photonic Band Gap (PGB) structures. The PGB cavity consists of a two-dimensional periodic array of high dielectric, low loss cylinders with a single removal defect, bounded on top and bottom by conducting sheets. We present the results of both numerical simulations and experimental measurements on the PGB cavity.

  12. Input cavity for high-order asymmetric-mode gyroklystron

    Science.gov (United States)

    Danilov, Yu. Yu.

    2012-06-01

    A new input cavity design for a high-order asymmetric-mode gyroklystron is proposed. Methods of the selective excitation of a resonant mode with a rotating field structure and the prevention of cavity self-excitation at harmonics of the gyrofrequency are proposed. Results of experimental investigation of the H711 mode cavity for a multimegawatt pulsed gyroklystron are presented.

  13. Computation Of An Optimal Laser Cavity Using Splines

    Science.gov (United States)

    Pantelic, Dejan V.; Janevski, Zoran D.

    1989-03-01

    As an attempt to improve the efficiency of a solid state laser cavity, a non-elliptical cavity is proposed. Efficiency was calculated by the ray trace method and the cavity was simulated using a novel approach with splines. Computation shows that substantial gain in efficiency can be achieved for a close coupled configuration.

  14. Photonic Band Gap structures: A new approach to accelerator cavities

    International Nuclear Information System (INIS)

    We introduce a new accelerator cavity design based on Photonic Band Gap (PGB) structures. The PGB cavity consists of a two-dimensional periodic array of high dielectric, low loss cylinders with a single removal defect, bounded on top and bottom by conducting sheets. We present the results of both numerical simulations and experimental measurements on the PGB cavity

  15. 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...

  16. BIOREACTOR WITH LID FOR EASY ACCESS TO INCUBATION CAVITY

    OpenAIRE

    Fey, S J; Wrzesinski, Krzysztof

    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.

  17. The Spindle Cell Neoplasms of the Oral Cavity

    OpenAIRE

    Shamim, Thorakkal

    2015-01-01

    Spindle cell neoplasms are defined as neoplasms that consist of spindle-shaped cells in the histopathology. Spindle cell neoplasms can affect the oral cavity. In the oral cavity, the origin of the spindle cell neoplasms may be traced to epithelial, mesenchymal and odontogenic components. This article aims to review the spindle cell neoplasms of the oral cavity with emphasis on histopathology.

  18. 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.

  19. Transverse beam cavity interaction. Pt. 2

    International Nuclear Information System (INIS)

    Intense bunches of charged particles in accelerators excite transverse higher modes in accelerating cavities. These higher modes lead to an interaction between widely separated bunches. Such multi bunch or multi turn instabilities due to long range forces can be described by the cavity mode frequencies and field patterns. For structures of cylindrical symmetry a computer code named URMEL is described which calculates resonant modes of any azimuthal mode number m=0,1,2.. (monopole, dipole, quadrupole, etc.). The eigenfrequencies are found as linear eigenvalues of a large matrix and simple mathematical procedures guarantee that no modes are missed. The combined use of URMEL in frequency domain and of the complementary code TBCI in time domain enables a complete analysis of long range -low frequency- forces (narrow band impedances) and short range -high frequency- forces (broad band impedances). (orig.)

  20. Parametric instabilities in the LCGT arm cavity

    Science.gov (United States)

    Yamamoto, K.; Uchiyama, T.; Miyoki, S.; Ohashi, M.; Kuroda, K.; Numata, K.

    2008-07-01

    We evaluated the parametric instabilities of LCGT (Japanese interferometric gravitational wave detector project) arm cavity. The number of unstable modes of LCGT is 10-times smaller than that of Advanced LIGO (USA). Since the strength of the instabilities of LCGT depends on the mirror curvature more weakly than that of Advanced LIGO, the requirement of the mirror curvature accuracy is easier to be achieved. The difference in the parametric instabilities between LCGT and Advanced LIGO is because of the thermal noise reduction methods (LCGT, cooling sapphire mirrors; Advanced LIGO, fused silica mirrors with larger laser beams), which are the main strategies of the projects. Elastic Q reduction by the barrel surface (0.2 mm thickness Ta2O5) coating is effective to suppress instabilities in the LCGT arm cavity. Therefore, the cryogenic interferometer is a smart solution for the parametric instabilities in addition to thermal noise and thermal lensing.

  1. Parametric instabilities in the LCGT arm cavity

    CERN Document Server

    Yamamoto, K; Miyoki, S; Ohashi, M; Kuroda, K; Numata, K

    2008-01-01

    We evaluated the parametric instabilities of LCGT (Japanese interferometric gravitational wave detector project) arm cavity. The number of unstable modes of LCGT is 10-times smaller than that of Advanced LIGO (U.S.A.). Since the strength of the instabilities of LCGT depends on the mirror curvature more weakly than that of Advanced LIGO, the requirement of the mirror curvature accuracy is easier to be achieved. The difference in the parametric instabilities between LCGT and Advanced LIGO is because of the thermal noise reduction methods (LCGT, cooling sapphire mirrors; Advanced LIGO, fused silica mirrors with larger laser beams), which are the main strategies of the projects. Elastic Q reduction by the barrel surface (0.2 mm thickness Ta$_2$O$_5$) coating is effective to suppress instabilities in the LCGT arm cavity. Therefore, the cryogenic interferometer is a smart solution for the parametric instabilities in addition to thermal noise and thermal lensing.

  2. Unifying Brillouin scattering and cavity optomechanics

    CERN Document Server

    Van Laer, Raphaël; Baets, Roel; Van Thourhout, Dries

    2015-01-01

    So far, Brillouin scattering and cavity optomechanics were mostly disconnected branches of research. Both deal with photon-phonon coupling, but a number of differences impeded their unambiguous fusion. Here, we reveal a close connection between two parameters of central importance in these fields: the Brillouin gain coefficient $\\tilde{\\mathcal{G}}$ and the zero-point optomechanical coupling rate $g_{0}$. In addition, we derive the dynamical cavity equations from the coupled-mode description of a Brillouin waveguide. This explicit transition shows the unity of optomechanical phenomena, such as stimulated Brillouin scattering and electromagnetically induced transparency, regardless of whether they occur in waveguides or in resonators. Therefore, the fields can no longer be disentangled. We propose an experimental manifestation of the link in silicon photonic nanowires.

  3. 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.

  4. Prototype rf cavity for the HISTRAP accelerator

    International Nuclear Information System (INIS)

    HISTRAP, a proposed synchrotron-cooling-storage ring designed to both accelerate and decelerate very highly charged very heavy ions for atomic physics research, requires an rf accelerating system to provide /+-/2.5 kV of peak accelerating voltage per turn while tuning through a 13.5:1 frequency range in a fraction of a second. A prototype half-wave, single gap rf cavity with biased ferrite tuning was built and tested over a continuous tuning range of 200 kHz through 2.7 MHz. Initial test results establish the feasibility of using ferrite tuning at the required rf power levels. The resonant system is located entirely outside of the accelerator's 15cm ID beam line vacuum enclosure except for a single rf window which serves as an accelerating gap. Physical separation of the cavity and the beam line permits in situ vacuum baking of the beam line at 300/degree/C

  5. Postirradiation flap infection about the oral cavity

    International Nuclear Information System (INIS)

    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

  6. Dielectric supported radio-frequency cavities

    Energy Technology Data Exchange (ETDEWEB)

    Yu, David U. L. (Rancho Palos Verdes, CA); Lee, Terry G. (Cupertino, CA)

    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.

  7. Buoyant Bubbles and Cavities in Galaxy Clusters

    Science.gov (United States)

    Jones, Thomas

    The latest generation of X-ray observatories has revealed a rich array of complex structures in galaxy intracluster media (ICMs). Remarkable among these discoveries is the common existence of X-ray ICM 'cavities' filled with radio synchrotron-emitting relativistic plasma. The cavities, which are generally paired and often multiple, range in size from a few kpc up to hundreds of kpc, are evidently the depositories of AGN jets. The energy contents of these 'bubbles' range above 1060 erg, making them potentially important players in ICM thermodynamics. They also carry potentially important cosmic ray and magnetic field constituents. The important problems of understanding their stability and dynamics, including how and where they share their contents are very active research topics that I will address in this talk. This work is supported by the US National Science Foundation and the University of Minnesota Supercomputing Institute.

  8. Quantum Dynamics of Nonlinear Cavity Systems

    CERN Document Server

    Nation, Paul D

    2010-01-01

    We investigate the quantum dynamics of three different configurations of nonlinear cavity systems. To begin, we carry out a quantum analysis of a dc superconducting quantum interference device (SQUID) mechanical displacement detector comprised of a SQUID with a mechanically compliant loop segment. The SQUID is approximated by a nonlinear current-dependent inductor, inducing a flux tunable nonlinear Duffing term in the cavity equation of motion. Expressions are derived for the detector signal and noise response where it is found that a soft-spring Duffing self-interaction enables a closer approach to the displacement detection standard quantum limit, as well as cooling closer to the ground state. Next, we make use of a superconducting transmission line formed from an array of dc-SQUIDs for investigating analogue Hawking radiation. Biasing the array with a space-time varying flux modifies the propagation velocity of the transmission line, leading to an effective metric with a horizon. This setup allows for quan...

  9. Cavity techniques for holographic data storage recording.

    Science.gov (United States)

    Miller, Bo E; Takashima, Yuzuru

    2016-03-21

    Conventionally, reading and writing of data holograms utilizes a fraction of the light power because of a trade off in write and read efficiencies. This system constraint can be mitigated by applying a resonator cavity. Cavities enable more efficient use of the available light leading to enhanced read and write data rates with no additional energy cost. This enhancement is inversely related to diffraction efficiency, so these techniques work well for large capacity holographic data storage having low diffraction efficiency. The enhancement in write data transfer rate is evaluated by writing plane wave holograms and image bearing holograms in Fe:LiNbO3 with a 532 nm wavelength laser. We confirmed 1.2 times enhancement in write data rate, out of a 1.4 theoretical maximum for materials absorption of 16%. PMID:27136822

  10. A microelectromechanically controlled cavity optomechanical sensing system

    CERN Document Server

    Miao, Houxun; Aksyuk, Vladimir

    2012-01-01

    Microelectromechanical systems (MEMS) have been applied to many measurement problems in physics, chemistry, biology and medicine. In parallel, cavity optomechanical systems have achieved quantum-limited displacement sensitivity and ground state cooling of nanoscale objects. By integrating a novel cavity optomechanical structure into an actuated MEMS sensing platform, we demonstrate a system with high quality-factor interferometric readout, electrical tuning of the optomechanical coupling by two orders of magnitude, and a mechanical transfer function adjustable via feedback. The platform separates optical and mechanical components, allowing flexible customization for specific scientific and commercial applications. We achieve displacement sensitivity of 4.6 fm/Hz^1/2 and force sensitivity of 53 aN/Hz^1/2 with only 250 nW optical power launched into the sensor. Cold-damping feedback is used to reduce the thermal mechanical vibration of the sensor by 3 orders of magnitude and to broaden the sensor bandwidth by a...

  11. 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.

  12. Non-perturbative calculations in cavity - QCD

    International Nuclear Information System (INIS)

    Thus far most calculations in cavity QCD have relied on perturbation theory to leading or next to leading order in αs. An attempt is made to go beyond pertubation theory and solve cavity QCD to arbitrary order in αs in a truncated Hilbert space. To this end, the matrix elements of the interaction Hamiltonian are evaluated, using basis states containing a sufficiently large number of gluons and/or quark-antiquark pairs. The spectrum and eigenvectors of the Hamiltonian are obtained by diagonolizing the Hamilton matrix. As a simple example, the interacting quark-antiquark system in a truncated basis consisting of quark-antiquark and quark-antquark-gluon states is treated. 3 figs., 5 refs

  13. 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.

  14. Optical cavity and transport system for FELI

    International Nuclear Information System (INIS)

    FELI (Free Electron Laser Research Institute, Inc.) is aiming at FIR-, IR-, VISIBLE-, and UV-FEL (spectral range from 0.3 to 22.7μm) generation using 30-, 75-, 120-, 165-MeV beams, respectively. The linear accelerator and four undulators are installed in the ground floor and five FEL users rooms are located in the third floor, so the longest FEL transport pass is about 80m long. We will adopt hole out coupling for FIR- and IR-FEL optical cavities. The output beam is collimated by an inverted telescope and transported to the users rooms via N2 purged pipes. Achieving optical beam stability and quality are primary concerns. For keeping optical beam stability and quality, a beam axis control unit and a position monitoring system are used. These optical cavities and FEL transport systems are under construction and will be used for FIR- and IR-FEL experiments in this summer. (author)

  15. A COMPARATIVE STUDY ON COPPER-PLATED UTERINE CAVITY SHAPED IUD AND NON-COPPER BEARING UTERINE CAVITY SHAPED IUD

    Institute of Scientific and Technical Information of China (English)

    ZENGQing-Gu; etal

    1989-01-01

    A comparative randomized clinical trial was carried out between two uterine cavity shaped IUDs: the copper-plated uterine cavity shaped IUD(UCDCu) and non-copper bearing uterine cavity shaped IUD(UCD). The IUDs were used by 1004 and 1005 women

  16. Cavity cooling and normal-mode spectroscopy of a bound atom-cavity system

    International Nuclear Information System (INIS)

    Full text: Single atoms strongly coupled to the field of an optical cavity form an attractive system for the realization of an atom-light interface useful for quantum information protocols. An experimental implementation of these schemes requires atoms which are trapped, cooled and localized in the cavity mode at a region of strong coupling. In the experiment presented here, single atoms are trapped and stored in a far-detuned intracavity dipole trap. We demonstrate cavity cooling by illuminating the system with a weak, slightly blue-detuned light beam. This extends the storage time of an atom, which is limited by parametric heating from fluctuations of the intracavity dipole trap, by more than a factor of two. The observed cooling force is of Sisyphus-type and was predicted. A special feature of this force is that it does not rely on the spontaneous emission of a photon by the atom, and therefore the cooling force is at least five times larger than the force achievable for free-space cooling methods with comparable excitation of a two-level atom. Preparing single atoms strongly-coupled to the mode of a high-finesse cavity in this way, we observe two well-resolved normal-mode peaks both in transmission of the cavity as well as in the trap lifetime. The experimental data agree well with a Monte Carlo simulation, demonstrating the localization of the atom to within a tenth of a wavelength at a cavity antinode. The ability to individually excite the normal modes of a bound atom-cavity system shows that we have reached good control over this fundamental quantum system. (author)

  17. Inflammatory Hyperplasia of the Oral Cavity

    OpenAIRE

    Ramachandran Sudarshan; G. Sree Vijayabala; KS Prem Kumar

    2012-01-01

    Oral inflammatory hyperplasias’ are the most common oral abnormalities. It manifests as diverse signs and symptoms. It may occur in any part of the oral cavity. They occur mainly due to reactive stimulus hence these lesions are called reactive hyperplasia. Distinguishing these entities and removal of etiological factors are essential. This review illustrates the various hyperplasia of the oral mucosa. Anahtar Kelimeler: [Archives Medical Review Journal 2012; 21(4.000): 299-307

  18. Thresholdless Lasing of Nitride Nanobeam Cavities

    OpenAIRE

    Jagsch, Stefan T.; Triviño, Noelia Vico; Callsen, Gordon; Kalinowski, Stefan; Rousseau, Ian M.; Carlin, Jean-François; Butté, Raphaël; Hoffmann, Axel; Grandjean, Nicolas; Reitzenstein, Stephan

    2016-01-01

    Exploring the limit of thresholdless operation is a central goal in the development of nanolasers. It goes along with a vivid debate about how to prove and interpret thresholdless lasing. Moreover, it is also relevant regarding future applications of nanolasers and large-scale photonic integration requiring energy-efficient coherent light emitters with small footprint. We present close to ideal lasing behavior of GaN nanobeam cavities grown on silicon. Due to their high optical quality, such ...

  19. Glial heterotopia of the oral cavity

    OpenAIRE

    Lizardo, Radhames E.; Simone Langness; Hassan Mumun; James Murphy; Robert Newbury; Patricia Bromberger; Bickler, Stephen W.

    2015-01-01

    We report an unusual case of a glial heterotopia arising from the oral cavity of an African neonate. The patient presented with an external pedunculated oral mass which was connected to the anterior hard palate by a firm, rubbery stalk of mucosal tissue. While the mass appeared painless, it interfered with the infant's feeding and was disturbing to the parents. After a computed tomography scan excluded an intracranial connection, the mass was excised at its base and sent for biopsy. Histopath...

  20. 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.

  1. Rotationally induced vortices in optical cavity modes

    CERN Document Server

    Habraken, Steven J M

    2008-01-01

    We show that vortices appear in the modes of an astigmatic optical cavity when it is put into rotation about its optical axis. We study the properties of these vortices and discuss numerical results for a specific realization of such a set-up. Our method is exact up to first order of the time-dependent paraxial approximation and involves bosonic ladder operators in the spirit of the quantum-mechanical harmonic oscillator.

  2. Water clusters confined in icosahedral fullerene cavities

    International Nuclear Information System (INIS)

    Graphical abstract: ■ Display Omitted Highlights: ► We model the interaction energy of water clusters confined in fullerene cavities. ► C60 and C180 are chosen as icosahedral cavities. ► The rigid TIP4P and flexible q-TIP4P/F water–water potentials are used. ► While C60 can confine exothermically only one water molecule, C180 does up to 17. ► New global minimum structures are reported for water clusters inside C180. - Abstract: Likely candidates for the global energy minima of endohedral (H2O)N-C60 and (H2O)N-C180, and exohedral (H2O)NC180 water–fullerene clusters with N ⩽ 20, are found using basin-hopping global optimization. The potential energy surfaces are constructed using both the rigid TIP4P and the flexible q-TIP4P/F potentials to model the water–water interaction, together with a Lennard–Jones potential for the water–fullerene interaction. In agreement with previous ab initio studies, we find that the small C60 cavity is able to encapsulate exothermically only one water molecule. On the other hand, the larger C180 cavity can encapsulate up to 17 water molecules exothermically. This threshold value is higher than that reported in a previous ab initio study (N ⩽ 12). New confined water cluster structures are found. One which is particularly interesting is the structure of (H2O)14-C180, with the water molecules forming an internal cage in which six oxygen atoms are located at the vertices of an almost regular octahedron and the eight remaining ones lie on top of the octahedron faces. For N ⩾ 15 one water molecule is always present at the center of the water cage, which is distorted to accommodate the extra molecules.

  3. Cavity QED Detection of Interfering Matter Waves

    OpenAIRE

    Bourdel, T; Donner, T.; Ritter, S; Öttl, A.; Köhl, M.; Esslinger, T.

    2005-01-01

    We observe the build-up of a matter wave interference pattern from single atom detection events in a double-slit experiment. The interference arises from two overlapping atom laser beams extracted from a Rubidium Bose-Einstein condensate. Our detector is a high-finesse optical cavity which realizes the quantum measurement of the presence of an atom and thereby projects delocalized atoms into a state with zero or one atom in the resonator. The experiment reveals simultaneously the granular and...

  4. Electromagnetic design of DTL cavity for LEHIPA

    International Nuclear Information System (INIS)

    This paper describes the electromagnetic design of the DTL. The 20 design of OTL cavities has been done using SUPERFISH in order to tune them to the operating frequency of 352.21 MHz with maximum shunt impedance. In order to incorporate the features that break the 20 symmetry, the 3D electromagnetic field simulations have been done using CST Microwave Studio code. The tuner and vacuum port have been modeled and their effect on the resonant frequency has been studied. (author)

  5. ORAL CAVITY: A MIRROR TO HIV MANIFESTATIONS

    OpenAIRE

    Harpreet Singh Grover; Amit Bhardwaj; Prateek Gupta

    2013-01-01

    A multitude of oral lesions have been described in individuals infected with the human immunodeficiency virus. Human immunodeficiency virus infection is a major interest and concern to dentists and other health care workers because of the many varieties of oral lesions often associated with Human immunodeficiency virus infection. Individual’s tested seropositive for Human immunodeficiency virus infections are more susceptible to occurrence of lesions in oral cavity. This review covers the cli...

  6. HARMONIC CAVITY PERFORMANCE FOR NSLS-II

    Energy Technology Data Exchange (ETDEWEB)

    BLEDNYKH, A.; KRINSKY, S.; PODOBEDOV, B.; ROSE, J.; TOWNE, N.; WANG, J.M.

    2005-05-15

    NSLS-II is a 3 GeV ultra-high brightness storage ring planned to succeed the present NSLS rings at BNL. Ultralow emittance combined with short bunch length means that it is critical to minimize the effects of Touschek scattering and coherent instabilities. Improved lifetime and stability can be achieved by including a third-harmonic RF cavity in the baseline design. This paper describes the required harmonic RF parameters and the expected system performance.

  7. Controlling spin relaxation with a cavity

    Science.gov (United States)

    Bienfait, A.; Pla, J. J.; Kubo, Y.; Zhou, X.; Stern, M.; Lo, C. C.; Weis, C. D.; Schenkel, T.; Vion, D.; Esteve, D.; Morton, J. J. L.; Bertet, P.

    2016-03-01

    Spontaneous emission of radiation is one of the fundamental mechanisms by which an excited quantum system returns to equilibrium. For spins, however, spontaneous emission is generally negligible compared to other non-radiative relaxation processes because of the weak coupling between the magnetic dipole and the electromagnetic field. In 1946, Purcell realized that the rate of spontaneous emission can be greatly enhanced by placing the quantum system in a resonant cavity. This effect has since been used extensively to control the lifetime of atoms and semiconducting heterostructures coupled to microwave or optical cavities, and is essential for the realization of high-efficiency single-photon sources. Here we report the application of this idea to spins in solids. By coupling donor spins in silicon to a superconducting microwave cavity with a high quality factor and a small mode volume, we reach the regime in which spontaneous emission constitutes the dominant mechanism of spin relaxation. The relaxation rate is increased by three orders of magnitude as the spins are tuned to the cavity resonance, demonstrating that energy relaxation can be controlled on demand. Our results provide a general way to initialize spin systems into their ground state and therefore have applications in magnetic resonance and quantum information processing. They also demonstrate that the coupling between the magnetic dipole of a spin and the electromagnetic field can be enhanced up to the point at which quantum fluctuations have a marked effect on the spin dynamics; as such, they represent an important step towards the coherent magnetic coupling of individual spins to microwave photons.

  8. Capture cavity II results at FNAL

    International Nuclear Information System (INIS)

    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

  9. The electromagnetic Casimir effect of spherical cavity

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The Casimir effect results from the zero-point energy of vacuum. A spherical cavity can be divided into three regions, and we make an analysis of every region and then give a formal solution of Casimir energy. The zeta-function regularization is also used to dispel the divergence of the summation. At the end, we can see the Casimir effect of a single sphere is included in our results.

  10. New Device for the Oral Cavity

    OpenAIRE

    Virginia Pentón García

    2010-01-01

    Background: Apart from the instruments used to work and develop adequate treatments, there are some other instruments in General Dentistry and in Orthodontics in particular, called auxiliary instruments or accessories that help to get a better view of surgical field. A capable surgeon appreciates good instruments and recognizes their urgent need in an efficient way. Objective: To show a new device to work in the oral cavity. Methods: the device which was made of 1,8 mm stainless steal wire...

  11. Rotationally induced vortices in optical cavity modes

    Science.gov (United States)

    Habraken, Steven J. M.; Nienhuis, Gerard

    2009-09-01

    We show that vortices appear in the modes of an astigmatic optical cavity when it is put into rotation about its optical axis. We study the properties of these vortices and discuss numerical results for a specific realization of such a set-up. Our method is exact up to first order in the time-dependent paraxial approximation and involves bosonic ladder operators in the spirit of the quantum-mechanical harmonic oscillator.

  12. Superconducting RF cavities film of bulk

    CERN Document Server

    Darriulat, Pierre

    1999-01-01

    The successful operation of LEP2 has demonstrated the feasibility of using on a large scale copper accelerating cavities coated with a thin superconducting niobium film. Yet other existing or planned installations such as CEBAF and TESLA, rely instead on the bulk niobium technology. The reason is a wide spread belief that the film technology would suffer from fundamental limitations preventing high gradients to be reached...

  13. Quasieigenstate coalescence in an atom-cavity quantum composite.

    Science.gov (United States)

    Choi, Youngwoon; Kang, Sungsam; Lim, Sooin; Kim, Wookrae; Kim, Jung-Ryul; Lee, Jai-Hyung; An, Kyungwon

    2010-04-16

    We report the first direct observation of an exceptional point (EP) in an open quantum composite of a single atom and a high-Q cavity mode. The atom-cavity coupling constant was made a continuous variable by utilizing the multisublevel nature of a single rubidium atom when it is optimally coupled to the cavity mode. The spectroscopic properties of quasieigenstates of the atom-cavity composite were experimentally investigated near the EP. Branch-point singularity of quasieigenenergies was observed and its 4pi symmetry was demonstrated. Consequently, the cavity transmission at the quasieigenstate was observed to exhibit a critical behavior at the EP. PMID:20481988

  14. 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.

  15. 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.

  16. Rapid cavity prototyping using mode matching and globalised scattering matrix

    CERN Document Server

    Shinton, I

    2009-01-01

    Cavity design using traditional mesh based numerical means (such as the finite element or finite difference methods) require large mesh calculations in order to obtain accurate values and cavity optimisation is often not achieved. Here we present a mode matching scheme which utilises a globalised scattering matrix approach that allows cavities with curved surfaces (i.e. cavities with elliptical irises and or equators) to be accurately simulated allowing rapid cavity prototyping and optimisation to be achieved. Results on structures in the CLIC main

  17. Experimental investigation of natural convection losses from open cavities

    International Nuclear Information System (INIS)

    Experimental results for natural convection in a cavity are reported. Both constrained andd unconstrained cavity geometries were studied. Detailed velocity profiles were obtained using Laser doppler velocimetry for Rayleigh numbers between 3 x 1010 and 2 x 1011, corresponding to a constant elevated wall temperature boundary condition. Characteristics of two-dimensional and three-dimensional flows obtained with dye flow visualization are discussed, including boundary layer transition to turbulence, flow patterns in the cavity, and flow outside of the cavity. Local Nusselt number is correlated with local Rayleigh number for constrained and unconstrained cavities

  18. Photon collection from a trapped ion--cavity system

    OpenAIRE

    Sterk, J. D.; Luo, L.; Manning, T. A.; P. Maunz; Monroe, C.

    2011-01-01

    We present the design and implementation of a trapped ion cavity QED system. A single ytterbium ion is confined by a micron-scale ion trap inside a 2 mm optical cavity. The ion is coherently pumped by near resonant laser light while the cavity output is monitored as a function of pump intensity and cavity detuning. We observe a Purcell enhancement of scattered light into the solid angle subtended by the optical cavity, as well as a three-peak structure arising from strongly driving the atom. ...

  19. 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.

  20. Scheme for Quantum Entanglement Swapping on Cavity QED System

    Institute of Scientific and Technical Information of China (English)

    CHEN Chang-Yong; YU Yan

    2006-01-01

    We propose a scheme for realizing quantum entanglement swapping between the atoms in cavity QED.With only virtual excitation of the cavity during the interaction between the atoms and cavity, the scheme is insensitive to the cavity mode states and the cavity decay. The ideas can also be utilized for realizing entanglement swapping between the atomic levels in a single atom and the atomic levels in the Bell states and between the atomic levels in the Bell states and the atomic levels in the W states.

  1. Scheme for Generation of Entanglement among Bimodal Cavities

    Institute of Scientific and Technical Information of China (English)

    SONG Xin-Guo; FENG Xun-Li

    2004-01-01

    @@ We present a scheme for generation of an entangled state in many spatially separated bimodal cavity modes via cavity quantum electrodynamics. A V-type three-level atom, initially prepared in a coherent superposition of its excited states, successively passes through both the bimodal cavities. If the atom is measured in its ground state after leaving the last cavity, an entangled state of many cavity modes can be generated. The conditions to generate the maximally entangled state with unity probability are worked out.

  2. Preparation of W state in resonant bimodal cavity quantum electrodynamics

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A scheme is proposed for generating entangled W states with four cavity modes. In this scheme, we send a Ⅴ-type three-level atom through two identical two-mode cavities in succession. After the atom exits from the second cavity,the four cavity modes are prepared in the W state. On the other hand we can obtain three-atom W states by sending three Ⅴ-type three-level atoms through a two-mode cavity in turn. The present scheme does not require conditional measurement, and it is easily generalized to preparing 2n-mode W states and n-atom W states.

  3. 35 GHz, 4-Cavity Gyroklystron Amplifier Experiment

    Science.gov (United States)

    Garven, M.; Calame, J. P.; Danly, B. G.; Levush, B.; Wood, F.

    1998-11-01

    Gyroklystron amplifiers operating in the Ka-band are attractive sources for the next generation of millimeter wave radars and are currently under investigation at the Naval Research Laboratory (NRL). A four-cavity, 35 GHz gyroklystron experiment has been designed to demonstrate higher saturated gain (50dB) than previous experiments at NRL( J. J. Choi et al, IEEE Trans. Plasma Sci. 26(3), 416, 1998.). Non-linear, time-dependent simulations of the 4-cavity gyroklystron amplifier design using MAGYKL(P. E. Latham et al IEEE Trans. Plasma Sci. 22, 804, 1994.) predict 35% efficiency, 225 kW peak power, 50 dB saturated gain and a -3 dB bandwidth of 0.6%. For this four-cavity gyroklystron, the interaction between the TE_01 mode and a 70 kV, 9 A electron beam was studied with α=1.3 and an rms perpendicular velocity spread of 9%. Initial studies have shown that variations in magnetic field and voltage affect the trade-offs between power, bandwidth and efficiency. Theoretical design studies and experimental progress will be presented.

  4. [Pigmented lesions of the oral cavity].

    Science.gov (United States)

    Brocheriou, C; Kuffer, R; Verola, O

    1985-01-01

    Pigmented lesions of the oral cavity are of multiple origin. They can be subdivided as follows: non tumoral pigmentations, non melanin pigmented tumors or tumor-like lesions, benign melanin pigmented tumors and malignant melanomas. Among non tumoral pigmented lesions, some of them show melanin deposits: they can be associated with a systemic disease (Peutz Jeghers syndrome, Addison's disease) or have a medicamentous origin, or belong to a lichen migricans. Non tumoral and non melanin pigmentations are principally due to a heavy metal accumulation or an accidental tatoo arising after tooth treatment. Peripheral giant cell granuloma, so-called giant cell epulis is the major non pigmented non melanin pseudotumoral lesion; pigmentation is due to hemosiderin deposits. In the oral cavity nevi are principally of the intramucosal type. Blue nevus, the second type in frequency, is usually located on the hard palate. Primary malignant melanomas are rare in the oral cavity, but it is--because its very bad prognosis--the most important lesion. In order to improve the survival it is necessary to do the diagnosis as early as possible. PMID:3833244

  5. Effects of cavity configuration on composite restoration.

    Science.gov (United States)

    Choi, Kyoung-Kyu; Ryu, Gil-Joo; Choi, Seung-Mo; Lee, Min-Jo; Park, Sang-Jin; Ferracane, Jack L

    2004-01-01

    This study evaluated the effects of various cavity configurations on the bond strength, microleakage, flexural strength and elastic modulus of a hybrid (Clearfil AP-X) and a microhybrid (Esthet-X) composite restorative. After the specimens were made with C-factors of less than 1, 2.4 and 3.4, flexural strength and elastic modulus were evaluated in three-point bending using a mechanical testing machine. Fragments of the fractured specimens were selected randomly and the fracture surfaces were examined in SEM. To evaluate the microtensile bond strength and microleakage of composite restorations in bovine cavities, C-factors (ratio of bonded to non-bonded cavity surface) were controlled as 1.0, 2.3, 3.0 and 3.7. All specimens were stored in distilled water at 37 degrees C for 24 hours and tested in a universal testing machine (EZ Test, Shimadzu, Japan). For the microleakage test, teeth with restorations were stained with silver nitrate and examined by two examiners under a stereomicroscope at 40x magnification. The hybrid composite showed higher mechanical properties than the microhybrid composite. The flexural strength and elastic modulus of both composites decreased when polymerized under greater constraint, that is, with increasing C-factor. Mean microtensile bond strength to dentin was also decreased with increasing C-factor for both types of composites. Microleakage scores for the hybrid composite restorations were generally higher than the microhybrid composite. PMID:15279488

  6. Erosion Modeling Analysis for SME Tank Cavity

    International Nuclear Information System (INIS)

    Previous computational work to evaluate erosion in the DWPF Slurry Mix Evaporator vessel has been extended to address the potential for the erosion to accelerate because of changes to the tank bottom profile. The same erosion mechanism identified in the previous work, abrasive erosion driven by high wall shear stress, was applied to the current evaluation. The current work extends the previous analysis by incorporating the observed changes to the tank bottom and coil support structure in the vicinity of the coil guides. The results show that wall shear on the tank bottom is about the same magnitude as found in previous results. Shear stresses in the eroded cavities are reduced compared to those that caused the initial erosion to the extent that anticipated continued erosion of those locations is minimal. If SR operations were continued at an agitator speed of 130 rpm, the edge of the existing eroded cavities would probably smooth out, while the rate of erosion at the bottom of the cavity would decrease significantly with time. Further, reducing the agitator speed to 103 rpm will reduce shear stresses throughout the bottom region of the tank enough to essentially preclude any significant continued erosion. Because this report is an extension to previously documented work, most background information has been omitted. A complete discussion of the motivation for both the analysis and the modeling is provided in Lee et al., ''Erosion Modeling Analysis for Modified DWPF SR Tank''

  7. Recent status of superconducting accelerator cavities

    International Nuclear Information System (INIS)

    RF Superconductivity has become an important technology for particle accelerators for high energy physics, nuclear physics and free electron lasers. More than 100 MVolts of Superconducting RF (SRF) cavities have been installed in accelerators for heavy ions and operated at gradients of 2-3 MV/m in excess of 105 hours. More than 500 MVolts are installed in electron accelerators and operated at gradients of 4-6 MV/m in excess of 104 hours. Enouraged by this success, another 500 meters of SRF cavities are in the production line, the major fraction to upgrade the energy of LEP to 100 GeV and to build CEBAF. New applications are forthcoming for a 1 GeV pion accelerator (PILAC) and for a high current e+e- collider in the B-quark energy range (B-factory). For the next linear collider in the TeV energy range, there are many compelling attractions to use SRF, if the gradients can be improved substantially and the costs lowered. Substantial progress has been made in understanding performance limitations and in inventing cures through better cavity geometries, materials and processes. Techniques are now in hand to reach 15-20 MV/m accelerating. In light of this progress, the potential of high gradient SRF for a TeV Energy Superconducting Linear Accelerator (TESLA) will be explored. (author)

  8. Cavity cooling of an optically levitated nanoparticle

    CERN Document Server

    Kiesel, Nikolai; Delic, Uros; Grass, David; Kaltenbaek, Rainer; Aspelmeyer, Markus

    2013-01-01

    The ability to trap and to manipulate individual atoms is at the heart of current implementations of quantum simulations, quantum computing, and long-distance quantum communication. Controlling the motion of larger particles opens up yet new avenues for quantum science, both for the study of fundamental quantum phenomena in the context of matter wave interference, and for new sensing and transduction applications in the context of quantum optomechanics. Specifically, it has been suggested that cavity cooling of a single nanoparticle in high vacuum allows for the generation of quantum states of motion in a room-temperature environment as well as for unprecedented force sensitivity. Here, we take the first steps into this regime. We demonstrate cavity cooling of an optically levitated nanoparticle consisting of approximately 10e9 atoms. The particle is trapped at modest vacuum levels of a few millibar in the standing-wave field of an optical cavity and is cooled through coherent scattering into the modes of the...

  9. 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...

  10. Atraumatic restorative treatment in atypical cavities

    Directory of Open Access Journals (Sweden)

    Letícia Simino Carvalho

    2009-10-01

    Full Text Available The atraumatic restorative treatment has been widely divulged among professionals in the area of Pediatric Dentistry. This restorative technique is included in the philosophy of Minimal Intervention and is considered one of the most conservative treatments, because only the layer of infected dentin caries is removed. Moreover, the atraumatic restorative treatment has been shown to be less painful than conventional approaches, and local anesthesia is rarely required. After the removal of the infected dentin, the cavities are filled with glass ionomer cement, a material that has antimicrobial capacity, good marginal sealing and constant fluorine release and recharge. In spite of the increasing number of studies about atraumatic restorative treatment, only studies related to restorations in occlusal cavities have shown scientific evidences about the technique. The aim of this study was to evaluate the feasibility of atraumatic restorative treatment in cavities with 3 or more surfaces involved, by means of a clinical case report of a patient with extensive dstruction in primary teeth, who was submitted to atraumatic restorative treatment, and observe the result of the treatment after one year of clinical and radiographic control.

  11. Cavity filling water control below aerator devices

    Institute of Scientific and Technical Information of China (English)

    钱尚拓; 吴建华; 马飞; 徐建荣; 彭育; 汪振

    2014-01-01

    With the rapid development of high dam projects within China, the dragon-drop-tail spillway tunnel is introduced and widely used. In view of the high water head and the large flow velocity on the dragon-drop-tail section, aerator devices are usually placed for the cavitation damage control. For the device placed in its initial position, it is a serious concern to design a suitable flow regime of the cavity and to control the cavity filling water due to the large flow depth and the low Froude number through this aera-tor. In this study, the relationships between the geometries of the aerator device and the jet impact angle of the lower trajectory of the flow are theoretically analyzed with/without a local slope. Nine test cases with different geometries are designed, the effectiveness of the filling water control is experimentally investigated under different operation conditions, and two criteria of the local slope design are proposed. It is concluded that the cavity flow regime and the filling water can be improved if a small impact angle and some sui-table geometries of the local slope are designed.

  12. Superconducting cavities for the APT accelerator

    International Nuclear Information System (INIS)

    The design of an Accelerator Production of Tritium (APT) facility being investigated at Los Alamos includes a linear accelerator using superconducting rf-cavities for the acceleration of a high-current cw proton beam. For electron accelerators with particles moving at the speed of light (β ∼ 1.0), resonators with a rounded shape, consisting of ellipsoidal and cylindrical sections, are well established. They are referred to as elliptical cavities. For the APT-design, this shape has been adapted for much slower proton beams with β ranging from 0.60 to 0.94. This is a new energy range, in which resonators of an elliptical type have never been used before. Simulations with the well-proven electromagnetic modeling tools MAFIA and SUPERFISH were performed. The structures have been optimized for their rf and mechanical properties as well as for beam dynamics requirements. The TRAK-RF simulation code is used to investigate potential multipacting in these structures. All the simulations will be put to a final test in experiments performed on single cell cavities that have started in the structures laboratory

  13. Machining of cavities for travelling wave LINAC

    International Nuclear Information System (INIS)

    A Traveling Wave (T.W.), 2π/3 mode electron linear accelerator of 2856 MHz is under development at CAT for radiation processing of agricultural products. This LINAC consists of a thermionic triode electron gun, TW buncher section and Regular Section. Machining of input/output couplers, regular section cells and disc were carried out using CNC lathe LAL- 2 BT and CNC milling machine BMV - 40. This paper highlights the dimensional and geometrical requirements of cavities, problems encountered during machining of OFE copper and their solutions to achieve high precision with ultrahigh surface finish. The performance of Linac depends upon a number of factors such as operating vacuum level, accuracies of cavity dimensions, materials, and surface finish of cavities comprising the LINAC. Each of these depends upon material and fabrication techniques used for manufacturing OFE copper of higher purity has been used since they offer lower surface resistivity and lower power losses. With CNC tuning and milling machines, the high surface finish has been achieved with higher dimensional and geometrical accuracies

  14. Feedback-free optical cavity with self-resonating mechanism

    Science.gov (United States)

    Uesugi, Y.; Hosaka, Y.; Honda, Y.; Kosuge, A.; Sakaue, K.; Omori, T.; Takahashi, T.; Urakawa, J.; Washio, M.

    2016-05-01

    We demonstrated the operation of a high finesse optical cavity without utilizing an active feedback system to stabilize the resonance. The effective finesse, which is a finesse including the overall system performance, of the cavity was measured to be 394 000 ± 10 000, and the laser power stored in the cavity was 2.52 ± 0.13 kW, which is approximately 187 000 times greater than the incident power to the cavity. The stored power was stabilized with a fluctuation of 1.7%, and we confirmed continuous cavity operation for more than two hours. This result has the potential to trigger an innovative evolution for applications that use optical resonant cavities such as compact photon sources with laser-Compton scattering or cavity enhanced absorption spectroscopy.

  15. Cryogenic rf test of the first plasma etched SRF cavity

    CERN Document Server

    Upadhyay, J; Popović, S; Valente-Feliciano, A -M; Im, D; Phillips, L; Vušković, L

    2016-01-01

    Plasma etching has a potential to be an alternative processing technology for superconducting radio frequency (SRF) cavities. An apparatus and a method are developed for plasma etching of the inner surfaces of SRF cavities. To test the effect of the plasma etching on the cavity rf performance, a 1497 MHz single cell SRF cavity is used. The single cell cavity is mechanically polished, buffer chemically etched afterwards and rf tested at cryogenic temperatures for a baseline test. This cavity is then plasma processed. The processing was accomplished by moving axially the inner electrode and the gas flow inlet in a step-wise manner to establish segmented plasma processing. The cavity is rf tested afterwards at cryogenic temperatures. The rf test and surface condition results are presented.

  16. Design and HOM study of Indus-1 RF cavity

    International Nuclear Information System (INIS)

    The radio frequency systems for booster and INDUS-1 storage ring have the same operating frequency 31.613 MHz. Capacitive loaded RF cavities at this frequency have been designed for both rings. Indus-1 storage ring had been commissioned at 450 MeV; beam current around 200 mA has been stored. The pressure in booster RF cavity is slightly higher than the remaining ring, which may degrade beam performance. Hence it was decided to replace booster RF cavity by INDUS-l RF cavity and newly designed RF cavity (presented in this paper) will be used for INDUS-1 ring. New INDUS-l RF cavity of torrespherical type has been designed. This paper describes the design feature of RF cavity and its Higher Order Modes (HOM) frequencies up to beam pipe cut-off frequency. (author)

  17. Blasting practices in a quarry with karstic cavities

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The blasting practices in a limestone quarry with karstic cavities have been presented. The existence of karstic cavities in the quarry has reduced blasting efficiency significantly. In order to improve blasting efficiency different blasting strategies (loading holes with ANFO in plastic bag, recording cavity location along the holes and charging the holes according to this information, and modifying blasting pattern according to karstic cavities) had been implemented and the results were evaluated on per ton cost basis. It was concluded that efficient blasting in such aquarries requires determining the size and shape of karstic cavities and based on this information, to modify the blast pattern and charge the holes. The suggested method is to record the cavity along the drill hole and to generate 3D model of cavities. By doing this, the production cost in the limestone quarry has decreased from 0.407 $/t to 0.354 $/t.

  18. Drag reduction using a multi-cavity at the afterbody

    Science.gov (United States)

    Sanmiguel-Rojas, Enrique; Martín-Alcántara, Antonio; Gutiérrez-Montes, Cándido; Martínez-Bazán, Carlos; Burgos, Manuel A.; Hidalgo-Martínez, Manuel

    2013-11-01

    We present a numerical study on the drag reduction of a two-dimensional bluff body with a blunt trailing edge, which has a chord length L, body height H and spanwise width W, being H / W cavity as a multi-cavity of variable depth h at the base of the body. It is observed within the range, 0 cavity depths are necessary to reach the same drag reduction with a multi-cavity than with a single-cavity. On the other hand, the temporal evolution of the drag coefficient shows a lower standard deviation with a multi-cavity than with a single-cavity, which is manifested in the flow as a wake with a lower level of disorder. This work was supported by Junta de Andalucía under project PI10-TEP5702.

  19. Radiologic and clinical observation of tuberculous cavity in initial treatment

    International Nuclear Information System (INIS)

    Tuberculous cavity is important in diagnosis and observation in the course of pulmonary tuberculosis. Author analyzed the radiologic findings of cavity and average months of negative conversion in AFB culture in 89 cases of initial treatment. The results were as follows: 1. The more number of cavities, the longer period in negative conversion of AFB culture. 2. No relation between sums of diameter and thickness of cavity and average months of negative conversion in AFB culture. 3. In the cases of cavity with air-fluid level took longer period in negative conversion og AFB culture than those of cavity without air-fluid level, significantly. 4. No relation between radiologic findings of cavity and results of chemotherapy for pulmonary tuberculosis.

  20. Effects of modulated electron beams and cavities on reditrons

    Science.gov (United States)

    Kwan, T. J. T.; Davis, H. A.; Fulton, R. D.; Sherwood, E. G.

    The virtual cathode, when formed in a cavity, can generate microwaves at different cavity modes depending on the geometry of the cavity. We found that the formation and the oscillation frequency of the virtual cathode in a reditron can be significantly influenced by cavity designs. The length of a cavity can play a role in frequency and mode selection. Our simulations showed that TM sub 012 and TM sub 033 were excited for cavity lengths of 15.0 cm and 22.5 cm, respectively. In addition to the cavity effects on reditrons, we discovered that highly modulated electron beams can be produced in reditrons. Full modulation (100 percent) of the transmitted electron beam current has been confirmed in our simulations. We further showed that incorporation of an inverse diode configuration can achieve microwave production efficiency of 26 percent.

  1. Effects of modulated electron beams and cavities on reditrons

    Energy Technology Data Exchange (ETDEWEB)

    Kwan, T.J.T.; Davis, H.A.; Fulton, R.D.; Sherwood, E.G.

    1988-01-01

    The virtual cathode, when formed in a cavity, can generate microwaves at different cavity modes depending on the geometry of the cavity. We found that the formation and the oscillation frequency of the virtual cathode in a reditron can be significantly influenced by cavity designs. The length of a cavity can play a role in frequency and mode selection. Our simulations showed that TM/sub 012/ and TM/sub 033/ were excited for cavity lengths of 15.0 cm and 22.5 cm, respectively. In addition to the cavity effects on reditrons, we discovered that highly modulated electron beams can be produced in reditrons. Full modulation (100/percent/) of the transmitted electron beam current has been confirmed in our simulations. We further showed that incorporation of an inverse diode configuration can achieve microwave production efficiency of 26/percent/. 11 refs., 8 figs.

  2. Development project for ERL superconducting spoke cavity accelerator

    International Nuclear Information System (INIS)

    We are proposing non-destructive assay system of nuclear materials with laser Compton scattering combined with an energy-recovery linac (ERL) and a laser. Since constructing accelerator system for nuclear safe guard and security requires small cavities, spoke cavities have many advantages such as shortening the distance between cavities, small frequency detune due to micro-phonics and easy adjustment of field distribution for strong cell coupling. Calculations of optimized cavity shape and HOM coupler shape have been performed and rf properties with aluminum spoke cavity model have been also measured. Considering refrigerator system required for superconducting accelerator, we are planning to develop 325MHz spoke cavity which can be practically operated with 4K liquid helium. We have started to fabricate the niobium 3-cell spoke cavity and will check the performance at the vertical test. (author)

  3. Formation of cavities in Si and their chemisorption of metals

    International Nuclear Information System (INIS)

    Nanometer-size cavities formed in Si by He+ implantation and annealing are examined with cross-section TEM. During annealing at 700 C or above, He degasses from the specimens, leaving uhv cavities with reactive Si bonds on their walls. Cavity microstructures have been characterized in detail for an implanted fluence of 1 x 1017 He/cm2: cavity volume remains approximately constant (0.75 lattice sites/He) for anneals from 700 to ∼1000 C, while surface area (3 to 7 times the wafer area) decreases with temperature as the cavities coarsen. The cavities are found to getter up to ∼1 monolayer of Cu or Au from solution in Si without second-phase formation, thus identifying the trapping mechanism as chemisorption on the cavity walls

  4. Writing and erasing of temporal cavity solitons by direct phase modulation of the cavity driving field.

    Science.gov (United States)

    Jang, Jae K; Erkintalo, Miro; Murdoch, Stuart G; Coen, Stéphane

    2015-10-15

    Temporal cavity solitons (CSs) are persisting pulses of light that can manifest themselves in continuously driven passive resonators, such as macroscopic fiber ring cavities and monolithic microresonators. Experiments so far have demonstrated two techniques for their excitation, yet both possess drawbacks in the form of system complexity or lack of control over soliton positioning. Here we experimentally demonstrate a new CS writing scheme that alleviates these deficiencies. Specifically, we show that temporal CSs can be excited at arbitrary positions through direct phase modulation of the cavity driving field, and that this technique also allows existing CSs to be selectively erased. Our results constitute the first experimental demonstration of temporal CS excitation via direct phase modulation, as well as their selective erasure (by any means). These advances reduce the complexity of CS excitation and could lead to controlled pulse generation in monolithic microresonators. PMID:26469612

  5. Linear cavity optical-feedback cavity-enhanced absorption spectroscopy with a quantum cascade laser.

    Science.gov (United States)

    Bergin, A G V; Hancock, G; Ritchie, G A D; Weidmann, D

    2013-07-15

    A cw distributed feedback quantum cascade laser (DFB-QCL) coupled to a two-mirror linear optical cavity has been used to successfully demonstrate optical-feedback cavity-enhanced absorption spectroscopy (OF-CEAS) at 5.5 μm. The noise-equivalent absorption coefficient, α(min), was 2.4×10(-8) cm(-1) for 1 s averaging, limited by etalon-fringing. The temporal stability of the instrument allows NO detection down to 5 ppb in 2 s. PMID:23939085

  6. HOMs simulation and measurement results of IHEP02 cavity

    Science.gov (United States)

    Zheng, Hong-Juan; Zhai, Ji-Yuan; Zhao, Tong-Xian; Gao, Jie

    2015-11-01

    In accelerator RF cavities, there exists not only the fundamental mode which is used to accelerate the beam, but also higher order modes (HOMs). The higher order modes excited by the beam can seriously affect beam quality, especially for the higher R/Q modes. 1.3 GHz low-loss 9-cell superconducting cavity as a candidate for ILC high gradient cavity, the properties of higher order mode has not been studied carefully. IHEP based on existing low loss cavity, designed and developed a large grain size 1.3 GHz low-loss 9-cell superconducting cavity (IHEP02 cavity). The higher order mode coupler of IHEP02 used TESLA coupler's design. As a result of the limitation of the mechanical design, the distance between higher order mode coupler and end cell is larger than TESLA cavity. This paper reports on measured results of higher order modes in the IHEP02 1.3 GHz low-loss 9-cell superconducting cavity. Using different methods, Qe of the dangerous modes passbands have been obtained. The results are compared with TESLA cavity results. R/Q of the first three passbands have also been obtained by simulation and compared with the results of the TESLA cavity. Supported by Knowledge Innovation Project of The Chinese Academy of Sciences

  7. Cavities and atomic packing in protein structures and interfaces.

    Directory of Open Access Journals (Sweden)

    Shrihari Sonavane

    2008-09-01

    Full Text Available A comparative analysis of cavities enclosed in a tertiary structure of proteins and interfaces formed by the interaction of two protein subunits in obligate and non-obligate categories (represented by homodimeric molecules and heterocomplexes, respectively is presented. The total volume of cavities increases with the size of the protein (or the interface, though the exact relationship may vary in different cases. Likewise, for individual cavities also there is quantitative dependence of the volume on the number of atoms (or residues lining the cavity. The larger cavities tend to be less spherical, solvated, and the interfaces are enriched in these. On average 15 A(3 of cavity volume is found to accommodate single water, with another 40-45 A(3 needed for each additional solvent molecule. Polar atoms/residues have a higher propensity to line solvated cavities. Relative to the frequency of occurrence in the whole structure (or interface, residues in beta-strands are found more often lining the cavities, and those in turn and loop the least. Any depression in one chain not complemented by a protrusion in the other results in a cavity in the protein-protein interface. Through the use of the Voronoi volume, the packing of residues involved in protein-protein interaction has been compared to that in the protein interior. For a comparable number of atoms the interface has about twice the number of cavities relative to the tertiary structure.

  8. Cavity parameters identification for TESLA control system development

    International Nuclear Information System (INIS)

    The control system modeling for the TESLA - TeV-Energy Superconducting Linear Accelerator project has been developed for the efficient stabilization of the pulsed, accelerating EM field of the resonator. The cavity parameters identification is an essential task for the comprehensive control algorithm. The TESLA cavity simulator has been successfully implemented by applying very high speed FPGA - Field Programmable Gate Array technology. The electromechanical model of the cavity resonator includes the basic features - Lorentz force detuning and beam loading. The parameters identification bases on the electrical model of the cavity. The model is represented by the state space equation for the envelope of the cavity voltage driven by the current generator and the beam loading. For a given model structure, the over-determined matrix equation is created covering the long enough measurement range with the solution according to the least squares method. A low degree polynomial approximation is applied to estimate the time-varying cavity detuning during the pulse. The measurement channel distortion is considered, leading to the external cavity model seen by the controller. The comprehensive algorithm of the cavity parameters identification has been implemented in the Matlab system with different modes of the operation. Some experimental results have been presented for different cavity operational conditions. The following considerations have lead to the synthesis of the efficient algorithm for the cavity control system predicted for the potential FPGA technology implementation. (orig.)

  9. Progress on SCRF cavity manufacturing activities at RRCAT

    International Nuclear Information System (INIS)

    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 Eacc of 20.3 MV/m at 2 K and 42 MV/m at 1.5-1.7 K with Qo of 2 x 1010 . The 650 MHz single cell cavity has achieved the Eacc > 19.3 MV/m with Q> 4x 1010 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)

  10. Development of a cavity enhanced aerosol albedometer

    Directory of Open Access Journals (Sweden)

    W. Zhao

    2014-03-01

    Full Text Available We report on the development of a cavity enhanced aerosol single scattering albedometer incorporating incoherent broad-band cavity-enhanced spectroscopy (IBBCEAS approach and an integrating sphere (IS for simultaneous in situ measurements of aerosol scattering and extinction coefficients in the exact same sample volume. The cavity enhanced albedometer employed a blue light-emitting diode (LED based IBBCEAS approach for the measurement of wavelength-resolved aerosol optical extinction over the spectral range of 445–480 nm. An integrating sphere nephelometer coupled to the IBBCEAS setup was used for the measurement of aerosol scattering. The scattering signal was measured with a single channel photomultiplier tube (PMT, providing an integrated value over a narrow bandwidth (FWHM ~ 9 nm in the spectral region of 465–474 nm. A scattering coefficient at a wavelength of 470 nm was deduced as an averaged scattering value and used for data analysis and instrumental performance comparison. Performance evaluation of the albedometer was carried out using laboratory-generated particles and ambient aerosol. The scattering and extinction measurements of monodisperse polystyrene latex (PSL spheres generated in laboratory proved excellent correlation between two channels of the albedometer. The retrieved refractive index (RI from the measured scattering and extinction efficiencies agreed well with the values reported in previously published papers. Aerosol light scattering and extinction coefficients, single scattering albedo (SSA and NO2 concentrations in an ambient sample were directly and simultaneously measured using the developed albedometer. The developed instrument was validated via an intercomparison of the measured aerosol scattering coefficient and NO2 trace concentration against a TSI 3563 integrating nephelometer and a chemiluminescence detector, respectively.

  11. Structure an dynamics in cavity quantum electrodynamics

    International Nuclear Information System (INIS)

    Much of the theoretical background related to the radiative processes for atoms in the presence of boundaries comes from two often disjoint areas, namely cavity quantum electrodynamics and optical bistability with two-state atoms. While the former of these areas has been associated to a large degree with studies in a perturbative domain of altered associated to a large degree with studies in a perturbative domain of altered emission processes in the presence of boundaries other than those of free space, the latter is often viewed from the perspective of hysteresis cycles and device applications. With the exception of the laser, however, perhaps the most extensive investigations of quantum statistical processes in quantum optics are to be found in the literature on bistability with two-state atoms and on cavity QED. Unfortunately, the degree of overlap of these two areas has not always been fully appreciated. This circumstance is perhaps due in part to the fact that the investigation of dynamical processes in cavity QED has had as its cornerstone the Jaynes-Cummings problem, with extensions to include, for example, small amounts of dissipation. On the other hand, a principle aspect of the bistability literature has been the study of quantum fluctuations in open systems for which dissipation plays a central role, but for which the coherent quantum dynamics of the Haynes-Cummings model are to a large measure lost due to the usual assumption of large system size and weak coupling (as in the standard theory of the laser). 132 refs., 26 figs., 1 tab

  12. Multiple metastatic tumors in the oral cavity

    OpenAIRE

    V.T. Beena; Swagatika Panda; Heera, R.; Rajeev, R.

    2011-01-01

    Metastatic lesions to the oral region are uncommon and account for approximately 1% of all malignant oral tumors. In 25% of the cases, oral metastases are found to be the first sign of the metastatic spread; and in 23% of the cases, it is the first indication of an undiscovered malignancy at a distant site. Metastases to oral soft tissues are even less frequent than jaw bones. Because of its rarity, the clinical presentation of a metastatic lesion in the oral cavity can be deceiving, leading ...

  13. Pump down rate for SRF cavities

    International Nuclear Information System (INIS)

    This note is about calculations aimed at quantifying adequate pumping speeds of evacuation of normally humid clean-room air from typical Superconducting Radiofrequency (SRF) cavities. The subject is of high relevance to the semiconductor industry, where the yield of VLSI (Very Large Scale Integration) chip production is affected by micron size particles which may cause fatal defects to their micron and sub-micron features. The recent availability of particle counters capable of operating in vacuum has stimulated measurements at reduced pressures in this subject

  14. Glial heterotopia of the oral cavity

    Directory of Open Access Journals (Sweden)

    Radhames E. Lizardo

    2015-07-01

    Full Text Available We report an unusual case of a glial heterotopia arising from the oral cavity of an African neonate. The patient presented with an external pedunculated oral mass which was connected to the anterior hard palate by a firm, rubbery stalk of mucosal tissue. While the mass appeared painless, it interfered with the infant's feeding and was disturbing to the parents. After a computed tomography scan excluded an intracranial connection, the mass was excised at its base and sent for biopsy. Histopathology examination confirmed glial heterotopia. Glial heterotopias should be included in the differential diagnosis of congenital masses in the oral region.

  15. Common problems of the oral cavity.

    Science.gov (United States)

    Halvorsen, J G

    1990-06-01

    The oral cavity is an area of the human body that is often given only cursory surveillance by primary care physicians. In this article, I have discussed a comprehensive approach for collecting subjective and objective data from the patient that is pertinent to oral conditions. Most common and critical problems have been reviewed in detail, focusing on their definition, epidemiology, pathophysiology, clinical manifestations, diagnosis, and management. This review is intended to sensitize physicians to the need to evaluate oral complaints more completely, to diagnose them more accurately, and to treat them more successfully. PMID:2196616

  16. Bifurcation structure of an optical ring cavity

    DEFF Research Database (Denmark)

    Kubstrup, C.; Mosekilde, Erik

    1996-01-01

    One- and two-dimensional continuation techniques are applied to determine the basic bifurcation structure for an optical ring cavity with a nonlinear absorbing element (the Ikeda Map). By virtue of the periodic structure of the map, families of similar solutions develop in parameter space. Within...... the individual family, the organization of the solutions exhibit an infinite number of regulatory arranged domains, the so-called swallow tails. We discuss the origin of this structure which has recently been observed in a variety of other systems as well....

  17. ORAL CAVITY: A MIRROR TO HIV MANIFESTATIONS

    Directory of Open Access Journals (Sweden)

    Harpreet Singh Grover

    2013-03-01

    Full Text Available A multitude of oral lesions have been described in individuals infected with the human immunodeficiency virus. Human immunodeficiency virus infection is a major interest and concern to dentists and other health care workers because of the many varieties of oral lesions often associated with Human immunodeficiency virus infection. Individual’s tested seropositive for Human immunodeficiency virus infections are more susceptible to occurrence of lesions in oral cavity. This review covers the clinical and therapeutics aspects of Human immunodeficiency virus associated oral diseases. Data was collected from detailed search through research and review articles of scientific journals and magazines as well as through Pubmed and National medical library database.

  18. Parallel Computation for Natural Convection in Cavities

    Science.gov (United States)

    Wang, P.; Ferraro, R. D.

    1995-01-01

    Parallel computation for thermal convective flows in cavities with adiabatic horizontal boundaries and driven by differential heating of the two vertical end walls, is investigated using supercomputers. A parallel computation code has been implemented using a finite-difference method with a multigrid elliptic solver and a Dufort-Frankel scheme. The domain decomposition techniques are discussed in detail. The parallel code is numerically stable, computationally efficient, and portable to various parallel architectures which support either PVM or NX libraries for communications. Finally, numerical results for various Rayleigh numbers and Prandtl numbers are presented.

  19. Cavities determine the pressure unfolding of proteins

    OpenAIRE

    Roche, Julien; Caro, Jose A.; Norberto, Douglas R.; Barthe, Philippe; Roumestand, Christian; Schlessman, Jamie L.; Garcia, Angel E.; García-Moreno E., Bertrand; Royer, Catherine A.

    2012-01-01

    It has been known for nearly 100 years that pressure unfolds proteins, yet the physical basis of this effect is not understood. Unfolding by pressure implies that the molar volume of the unfolded state of a protein is smaller than that of the folded state. This decrease in volume has been proposed to arise from differences between the density of bulk water and water associated with the protein, from pressure-dependent changes in the structure of bulk water, from the loss of internal cavities ...

  20. Oral Cavity Clear Cell Odontogenic Carcinoma.

    Science.gov (United States)

    Ginat, Daniel Thomas; Villaflor, Victoria; Cipriani, Nicole A

    2016-06-01

    A case of clear cell odontogenic carcinoma of the oral cavity is described in this sine qua non radiology-pathology correlation article. CT demonstrated a solid and cystic mass arising from the mandible. Histology demonstrated variably-sized nests of clear to pale eosinophilic cells with occasional central necrosis embedded in a hyalinized to fibrocellular stroma. The specimen was also positive for the characteristic rearrangement of the EWSR1 (22q12) locus in 93.5 % of interphase cells. PMID:25994920

  1. Macroscopic Quantum Superposition in Cavity Optomechanics.

    Science.gov (United States)

    Liao, Jie-Qiao; Tian, Lin

    2016-04-22

    Quantum superposition in mechanical systems is not only key evidence for macroscopic quantum coherence, but can also be utilized in modern quantum technology. Here we propose an efficient approach for creating macroscopically distinct mechanical superposition states in a two-mode optomechanical system. Photon hopping between the two cavity modes is modulated sinusoidally. The modulated photon tunneling enables an ultrastrong radiation-pressure force acting on the mechanical resonator, and hence significantly increases the mechanical displacement induced by a single photon. We study systematically the generation of the Yurke-Stoler-like states in the presence of system dissipations. We also discuss the experimental implementation of this scheme. PMID:27152802

  2. 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.

  3. Manifestation of psoriasis in the oral cavity.

    Science.gov (United States)

    Fatahzadeh, Mahnaz

    2016-03-01

    Despite the common prevalence of cutaneous psoriasis, the existence of manifestations in the oral cavity is subject to controversy. In this article, dermatologic psoriasis is reviewed, and a patient with generalized, symptomatic oral mucosal erythema resembling atrophic candidiasis synchronous with flare of chronic skin psoriasis is described. Diagnostic work up and therapeutic response supported that these mucosal findings were the oral counterpart of cutaneous disease. Dental providers should be familiar with the signs and symptoms of oral psoriasis, institute appropriate preventive measures, and provide palliation directed at symptomatic oral changes of psoriasis. PMID:26665263

  4. A coupled microwave-cavity system in the Rydberg-atom cavity detector for dark matter axions

    CERN Document Server

    Tada, M; Shibata, M; Kominato, K; Ogawa, I; Funahashi, H; Yamamoto, K; Matsuki, S

    2001-01-01

    A coupled microwave-cavity system of cylindrical TM$_{010}$ single-mode has been developed to search for dark matter axions around 10 $\\mu {\\rm eV}$(2.4 GHz) with the Rydberg-atom cavity detector at 10 mK range temperature. One component of the coupled cavity (conversion cavity) made of oxygen-free high-conductivity copper is used to convert an axion into a single photon with the Primakoff process in the strong magnetic field, while the other component (detection cavity) made of Nb is utilized to detect the converted photons with Rydberg atoms passed through it without magnetic field. Top of the detection cavity is attached to the bottom flange of the mixing chamber of a dilution refrigerator, thus the whole cavity is cooled down to 10 mK range to reduce the background thermal blackbody-photons in the cavity. The cavity resonant frequency is tunable over $\\sim$ 15% by moving dielectric rods inserted independently into each part of the cavities along the cylindrical axis. In order to reduce the heat load from ...

  5. Mode identification and cavity stretching for the prototype storage ring cavity

    International Nuclear Information System (INIS)

    The Advanced Photon Source (APS) storage ring uses single cell cavities. As described in the paper ''Coupled Bunch Instabilities in the APS Ring'' by L. Emery, several of the higher order modes (HOM) in these cavities cause instability thresholds below the desired operating level. In order to clearly identify these modes, an experimental method of measuring the fields is necessary. A well- known technique is measurement with probes or loops extending in from the walls, but this cannot be used in the interior. A different approach is the use of small perturbations which cause a frequency shift that is related in a known way to the local field. This perturbation can be calculated for objects of needle-shaped, spherical, and disk-shaped form. With proper use this method can give very accurate measurements of the direction and magnitude of the electric and magnetic fields. This report gives examples of a method of measuring electric field strengths in a resonant cavity. It is shown that insertion of a metallic bead (needle), whose dimensions are small compared to the wavelength, perturbs the frequency of a resonant electromagnetic cavity by an amount that depends upon the local electric field at the position of the perturbing object

  6. Cavity quantum electrodynamics of a quantum dot in a micropillar cavity: comparison between experiment and theory

    DEFF Research Database (Denmark)

    Madsen, Kristian Høeg; Ates, Serkan; Reitzenstein, S.;

    2010-01-01

    The coupling between a quantum dot (QD) and a micropillar cavity is experimentally investigated by performing time-resolved, correlation, and two-photon interference measurements. The Jaynes-Cummings model including dissipative Lindblad terms and dephasing is analyzed, and all the parameters for ...

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

    Science.gov (United States)

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

    2006-07-01

    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.

  8. Manufacturing of indigenous RF cavity for Indus-2

    International Nuclear Information System (INIS)

    At present four, 505.8 MHz, imported copper RF cavities are being used in Indus-2 synchrotron radiation source. These cavities are used to impart energy to the electron beam to attain the required energy level and also maintain it. From first stage of accelerator i.e booster synchrotron the electron beam is injected into Indus-2 ring where the beam energy is increased from 550 MeV to 2.5 GeV using these cavities. Indigenous developmental work is initiated to fabricate RF cavities using in-house manufacturing facilities. For fabrication of this cavity various innovative tasks were executed which includes, development of forming tools, optimization of machining parameters, development of cutting tools, various brazing trials, brazing procedure qualification, design and development of machining and brazing fixtures, optimization of chemical cleaning procedure etc. The paper also discusses about specifications of the cavity, its vacuum testing and RF testing results. (author)

  9. 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.

  10. Reactive RF Tuning For Compensation of a Detuned Accelerating Cavity

    International Nuclear Information System (INIS)

    The resonant frequency of an accelerating RF cavity is detuned from the desired frequency by certain physical disturbances, such as thermal and other mechanical wall distortions. Cavity wall distortions due to microphonics (acoustic vibrations) and the Lorentz force (radiation pressure) can be serious problems in pulsed RF operation of superconducting (SRF) cavities with thin cavity walls and a high quality factor. The resulting detuning results a change of input reactance. The offset reactance at the cavity input may be tuned out properly with a reactive element in the input transmission line, so that the generator RF power can be delivered efficiently to the cavity. A fast response electrical tuner may be built for compensating high frequency detuning without any mechanical coupling

  11. 201 MHz Cavity R and D for MUCOOL and MICE

    International Nuclear Information System (INIS)

    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

  12. Stability analysis for bad cavity lasers with inhomogeneously broadened gain

    CERN Document Server

    Kazakov, Georgy A

    2016-01-01

    Bad cavity lasers are experiencing renewed interest in the context of active optical frequency standards, due to their enhanced robustness against fluctuations of the laser cavity. The gain medium would consist of narrow-linewidth atoms, either trapped inside the cavity or intersecting the cavity mode dynamically. A finite velocity distribution, atomic interactions, or interactions of realistic multilevel atoms with external field leads to an inhomogeneous broadening of the atomic gain profile. This can bring the bad cavity laser to operate in unstable regimes characterized by complex temporal patterns of the field amplitude. We present a new and efficient method for the stability analysis of bad cavity lasers with inhomogeneously broadened gain. We apply this method to identify the steady-state solutions for the metrology-relevant case of spin-1/2 atoms interacting with an external magnetic field.

  13. The first operation of 56 MHz SRF cavity in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Q. [Brookhaven National Lab. (BNL), Upton, NY (United States); Belomestnykh, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Ben-Zvi, I. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); DeSanto, L. [Brookhaven National Lab. (BNL), Upton, NY (United States); Goldberg, D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Harvey, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Hayes, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); McIntyre, G. [Brookhaven National Lab. (BNL), Upton, NY (United States); Mernick, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Orfin, P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Seberg, S. [Brookhaven National Lab. (BNL), Upton, NY (United States); Severino, F. [Brookhaven National Lab. (BNL), Upton, NY (United States); Smith, K. [Brookhaven National Lab. (BNL), Upton, NY (United States); Than, R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Zaltsman, A. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-05-03

    A 56 MHz superconducting RF cavity has been designed, fabricated and installed in the Relativistic Heavy Ion Collider (RHIC). The cavity operates at 4.4 K with a “quiet helium source” to isolate the cavity from environmental acoustic noise. The cavity is a beam driven quarter wave resonator. It is detuned and damped during injection and acceleration cycles and is brought to operation only at store energy. For a first test operation, the cavity voltage was stabilized at 300 kV with full beam current. Within both Au + Au and asymmetrical Au + He3 collisions, luminosity improvement was detected from direct measurement, and the hourglass effect was reduced. One higher order mode (HOM) coupler was installed on the cavity. We report in this paper on our measurement of a broadband HOM spectrum excited by the Au beam.

  14. GaN hemispherical micro-cavities

    Science.gov (United States)

    Zhang, Yiyun; Feng, Cong; Wang, T.; Choi, H. W.

    2016-01-01

    GaN-based micro-dome optical cavities supported on Si pedestals have been demonstrated by dry etching through gradually shrinking microspheres followed by wet-etch undercutting. Optically pumped whispering-gallery modes (WGMs) have been observed in the near-ultraviolet within the mushroom-like cavities, which do not support Fabry-Pérot resonances. The WGMs blue-shift monotonously as the excitation energies are around the lasing threshold. Concurrently, the mode-hopping effect is observed as the gain spectrum red-shifts under higher excitations. As the excitation energy density exceeds ˜15.1 mJ/cm2, amplified spontaneous emission followed by optical lasing is attained at room temperature, evident from a super-linear increase in emission intensity together with linewidth reduction to ˜0.7 nm for the dominant WGM. Optical behaviors within these WGM microcavities are further investigated using numerical computations and three-dimensional finite-difference time-domain simulations.

  15. Ultrasonic Abrasion: An Alternative for Cavity Preparation

    Directory of Open Access Journals (Sweden)

    Áurea Simone Barrôso VIEIRA

    2007-05-01

    Full Text Available Introduction: Restorative dentistry aims to repair damages caused by caries disease. Along the years, researchers have developed effective and less invasive methods with the goal of preserving the teeth from caries destruction. Therefore, the improvement of scientific knowledge, auxiliary diagnostic systems, dental materials, and new instruments has changed the approaches and treatments in this field. In addition to conservative removal of carious tissue, patient’s comfort has also become a concern in modern dentistry.Purpose: Considering that ultrasonic abrasion has attracted great interest of dental professionals, this article discusses an alternative technique for cavity preparation by literature review, addressing its indications, contra-indications, advantages and limitations compared to the conventional high-speed method.Conclusion: There are not many studies on this subject. The available studies have demonstrated several qualities of the ultrasonic abrasion system, but some aspects remain unclear. Therefore, it is important to highlight that laboratorial and clinical studies in primary/permanent teeth should be conducted to elucidate questionable issues, such as time of cavity preparation, topography, presence of smear layer and microleakage, in order to offer safety to the extensive use of this new technology for both the professional and the patient. In this context, the dentist should always be attentive to innovations referring to minimally invasive techniques.

  16. The inner cavity of the circumnuclear disc

    CERN Document Server

    Blank, Marvin; Frank, Adam; Carroll-Nellenback, Jonathan J; Duschl, Wolfgang J

    2016-01-01

    The circumnuclear disc (CND) orbiting the Galaxy's central black hole is a reservoir of material that can ultimately provide energy through accretion, or form stars in the presence of the black hole, as evidenced by the stellar cluster that is presently located at the CND's centre. In this paper, we report the results of a computational study of the dynamics of the CND. The results lead us to question two paradigms that are prevalent in previous research on the Galactic Centre. The first is that the disc's inner cavity is maintained by the interaction of the central stellar cluster's strong winds with the disc's inner rim, and second, that the presence of unstable clumps in the disc implies that the CND is a transient feature. Our simulations show that, in the absence of a magnetic field, the interaction of the wind with the inner disc rim actually leads to a filling of the inner cavity within a few orbital time-scales, contrary to previous expectations. However, including the effects of magnetic fields stabi...

  17. Cavity-assisted quantum bath engineering

    Science.gov (United States)

    Murch, Kater

    2013-03-01

    In practice, quantum systems are never completely isolated, but instead interact with degrees of freedom in the surrounding environment, eventually leading to decoherence. Precision measurement techniques such as nuclear magnetic resonance and interferometry, as well as envisioned quantum schemes for computation, simulation, and data encryption, rely on the ability to prepare and preserve delicate quantum superpositions and entanglement. The conventional route to long-lived quantum coherence involves minimizing coupling to a dissipative bath. Paradoxically, it is possible to instead engineer specific couplings to a quantum environment that allow dissipation to actually preserve coherence. I will discuss our recent demonstration of quantum bath engineering for a superconducting qubit 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 qubit to an arbitrarily specified coherent superposition of the ground and excited states. In the presence of background thermal excitations, this mechanism increases the state purity and effectively cools the dressed atom state to a low temperature. We envision that future multi-qubit implementations could enable the preparation of entangled many-body states suitable for quantum simulation and computation. This work was supported by the IARPA CSQ program.

  18. Rf cavity primer for cyclic proton accelerators

    International Nuclear Information System (INIS)

    The purpose of this note is to describe the electrical and mechanical properites of particle accelerator rf cavities in a manner which will be useful to physics and engineering graduates entering the accelerator field. The discussion will be limited to proton (or antiproton) synchrotron accelerators or storage rings operating roughly in the range of 20 to 200 MHz. The very high gradient, fixed frequency UHF or microwave devices appropriate for electron machines and the somewhat lower frequency and broader bandwidth devices required for heavy ion accelerators are discussed extensively in other papers in this series. While it is common pratice to employ field calculation programs such as SUPERFISH, URMEL, or MAFIA as design aids in the development of rf cavities, we attempt here to elucidate various of the design parameters commonly dealt with in proton machines through the use of simple standing wave coaxial resonator expressions. In so doing, we treat only standing wave structures. Although low-impedance, moderately broad pass-band travelling wave accelerating systems are used in the CERN SPS, such systems are more commonly found in linacs, and they have not been used widely in large cyclic accelerators. Two appendices providing useful supporting material regarding relativistic particle dynamics and synchrotron motion in cyclic accelerators are added to supplement the text

  19. ANT tuner retrofit for LEB cavity

    International Nuclear Information System (INIS)

    This report describes a ferrite tuner design for the LEB cavity that utilizes techniques for bonding ferrite to metallic cooling plates that is utilized in the high-power rf and microwave industry. A test tuner was designed to fit into the existing LEB-built magnet and onto the Grimm LEB Cavity. It will require a new vacuum window in order to attain maximal tuning range and high voltage capability and a new center conductor of longer length and a different vacuum window connection than the Grimm center conductor. However, the new center conductor will be essentially identical to the Grimm center conductor in its basic construction and in the way it connects to the stand for support. The tuner is mechanically very similar to high-power stacked circulators built by ANT of Germany and was designed according to ANT's established engineering and design criteria and SSC LEB tuning and power requirements. The tuner design incorporates thin tiles of ferrite glued using a high-radiation-resistance epoxy to copper-plated stainless steel cooling plates of thickness 6.5 mm with water cooling channels inside the plates. The cooling plates constitute 16 pie-shaped segments arranged in a disk. They are electrically isolated from each other to suppress eddy currents. Five of these disks are arranged in parallel with high-pressure rf contacts between the plates at the outer radius. The end walls are slotted copper-plated stainless steel of thickness 3 mm

  20. Imaging of the peritoneal cavity in CAPD.

    Science.gov (United States)

    Wankowicz, Z; Pietrzak, B; Skrobowska, E

    1996-01-01

    The aim of our study was the use of the optimal imaging of the peritoneal cavity (PC) for continuous ambulatory peritoneal dialysis (CAPD)-related problems. Ultrasonography (USG), direct abdominal radiography (DAR), peritoneoscintigraphy (PSG), and standard peritoneo-computed tomography (PCT) with reconstruction (R-PCT) were performed in 25 patients on CAPD from three to 44 months. Studies were done at the beginning of CAPD (1-3 months) as well as in the noncomplicated and complicated course of CAPD. Group 1 comprised 17 patients in whom 77 PC images were taken in the non-complicated course of CAPD. Group II comprised 15 patients in whom 65 images were taken during or after complications. For USG and DAR we used standard equipment, PSG was done with sulfur colloid labeled with technetium 99m (Tc 99m), PCT, and R-PCT were done with Omnipaque and Somatom HiQ Siemens unit. In PCT, two- and three dimensional reconstruction were done by our own computer program. USG was recommended for imaging of tunnel infections, exit-site infection (ESI), and adhesion. PSG was useful in almost all observed complications of CAPD except thickening of the peritoneal membrane (PM). Standard PCT with R-PCT was more useful than PCT because of a more legible image of the peritoneal cavity, which gives the possibility of monitoring fluid distribution and measuring of intraperitoneal fluid volume. PMID:8728239

  1. Rf cavity primer for cyclic proton accelerators

    Science.gov (United States)

    Griffin, J. E.

    1988-04-01

    The electrical and mechanical properities of particle accelerator rf cavities are described in a manner which will be useful to physics and engineering graduates entering the accelerator field. The discussion is limited to proton (or antiproton) synchrotron accelerators or storage rings operating roughly in the range of 20 to 200 MHz. The very high gradient, fixed frequency UHF or microwave devices appropriate for electron machines and the somewhat lower frequency and broader bandwidth devices required for heavy ion accelerators are discussed extensively in other papers in this series. While it is common practice to employ field calculation programs such as SUPERFISH, URMEL, or MAFIA as design aids in the development of rf cavities, we attempt here to elucidate various of the design parameters commonly dealt with in proton machines through the use of simple standing wave coaxial resonator expressions. In so doing, we treat only standing wave structures. Although low-impedance, moderately broad pass-band travelling wave accelerating systems are used in the CERN SPS, such systems are more commonly found in linacs, and they have not been used widely in large cyclic accelerators. Two appendices providing useful supporting material regarding relativistic particle dynamics and synchrotron motion in cyclic accelerators are added to supplement the text.

  2. 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.

  3. Field quantization for open optical cavities

    CERN Document Server

    Viviescas, C

    2003-01-01

    We study the quantum properties of the electromagnetic field in optical cavities coupled to an arbitrary number of escape channels. We consider both inhomogeneous dielectric resonators with a scalar dielectric constant $\\epsilon({\\bf r})$ and cavities defined by mirrors of arbitrary shape. Using the Feshbach projector technique we quantize the field in terms of a set of resonator and bath modes. We rigorously show that the field Hamiltonian reduces to the system--and--bath Hamiltonian of quantum optics. The field dynamics is investigated using the input--output theory of Gardiner and Collet. In the case of strong coupling to the external radiation field we find spectrally overlapping resonator modes. The mode dynamics is coupled due to the damping and noise inflicted by the external field. For wave chaotic resonators the mode dynamics is determined by a non--Hermitean random matrix. Upon including an amplifying medium, our dynamics of open-resonator modes may serve as a starting point for a quantum theory of ...

  4. 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.

  5. Charge fluctuations in open chaotic cavities

    International Nuclear Information System (INIS)

    We present a discussion of the charge response and the charge fluctuations of mesoscopic chaotic cavities in terms of a generalized Wigner-Smith matrix. The Wigner-Smith matrix is well known in investigations of time-delay of quantum scattering. It is expressed in terms of the scattering matrix and its derivatives with energy. We consider a similar matrix but instead of an energy derivative, we investigate the derivative with regard to the electric potential. The resulting matrix is then the operator of charge. If this charge operator is combined with a self-consistent treatment of Coulomb interaction, the charge operator determines the capacitance of the system, the non-dissipative ac-linear response, the RC-time with a novel charge relaxation resistance, and in the presence of transport a resistance that governs the displacement currents induced into a nearby conductor. In particular, these capacitances and resistances determine the relaxation rate and dephasing rate of a nearby qubit (a double quantum dot). We discuss the role of screening of mesoscopic chaotic detectors. Coulomb interaction effects in quantum pumping and in photon assisted electron-hole shot noise are treated similarly. For the latter, we present novel results for chaotic cavities with non-ideal leads

  6. Devil's Staircase in an Optomechanical Cavity

    CERN Document Server

    Wang, Hui; Buks, Eyal

    2016-01-01

    We study self-excited oscillation (SEO) in an on-fiber optomechanical cavity. While the phase of SEO randomly diffuses in time when the laser power that is injected into the cavity is kept constant, phase locking may occur when the laser power is periodically modulated in time. We investigate the dependence of phase locking on the amplitude and frequency of the laser power modulation. We find that phase locking can be induced with a relatively low modulation amplitude provided that the ratio between the modulation frequency and the frequency of SEO is tuned close to a rational number of relatively low hierarchy in the Farey tree. To account for the experimental results a one dimensional map, which allows evaluating the time evolution of the phase of SEO, is theoretically derived. By calculating the winding number of the one dimensional map the regions of phase locking can be mapped in the plane of modulation amplitude and modulation frequency. Comparison between the theoretical predictions and the experimenta...

  7. On the applicability of conventional transmission line theory within cavities

    OpenAIRE

    Gronwald, F.

    2006-01-01

    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 properti...

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

    OpenAIRE

    Kalaitsidou, Ioanna G.; Ioannis T. Astreidis; Kontos, Konstantinos I.; Lazaridou, Maria N.; Eleni T. Bourlidou; Gerasimidou, Domniki K; Vladika, Natalia P.; Mangoudi, Doxa L.

    2015-01-01

    ABSTRACT 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 approac...

  9. Linear Epidermal Nevus of the Oral Cavity: A Rare Diagnosis

    OpenAIRE

    Mariana Dutra de Cássia Ferreira Santos; Alexandre Scalli Mathias Duarte; Guilherme Machado de Carvalho; Alexandre Caixeta Guimarães; Carlos Eduardo Monteiro Zappelini; Ana Cristina Coelho Dal Rio; Maria Elvira Pizzigatti Corrêa; Albina Messias de Almeida Milani Altemani; Ester Maria Danielli Nicola

    2012-01-01

    Linear epidermal nevus is an uncommon diagnosis of benign lesions of the oral cavity. It is characterized by a congenital malformation arising from the ectoderm cells, which are arranged according to a typical linear configuration known as Blaschko’s lines. We report a case of linear epidermal nevus of oral cavity in a 51-year-old lady or woman. The linear epidermal nevus of the oral cavity, although rare, can be considered a differential diagnosis of oral papillomatosis (OP). The histopathol...

  10. Realization of a semiconductor-based cavity soliton laser

    OpenAIRE

    Tanguy, Y.; Ackemann, T.; Firth, W. J.; Jaeger, R.

    2007-01-01

    The realization of a cavity soliton laser using a vertical-cavity surface-emitting semiconductor gain structure coupled to an external cavity with a frequency-selective element is reported. All-optical control of bistable solitonic emission states representing small microlasers is demonstrated by injection of an external beam. The control scheme is phase-insensitive and hence expected to be robust for all-optical processing applications. The motility of these structures is also demonstrated.

  11. Commissioning Cornell OSTs for SRF cavity testing at Jlab

    International Nuclear Information System (INIS)

    Understanding the current quench limitations in SRF cavities is a topicessential for any SRF accelerator that requires high fields. This understanding crucially depends on correct and precise quench identification. Second sound quench detection in superfluid liquid helium with oscillating superleak transducers is a technique recently applied at Cornell University as a fast and versatile method for quench identification in SRF cavities. Having adopted Cornell design, we report in this contribution on our experience with OST for quench identification in different cavities at JLab

  12. Modeling of Electromagnetic Heating in RF Copper Accelerating Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Awida, M. H. [Fermilab; Gonin, I. [Fermilab; Romanov, Romanov [Fermilab; Khabiboulline, T. [Fermilab; Yakovlev, V. [Fermilab

    2016-01-17

    Electromagnetic heating is a critical issue in normal conducting copper RF cavities that are employed in particle accelerators. With several tens to hundreds of kilowatts dissipated RF power, there must be an effective cooling scheme whether it is water or air based or even a combination of both. In this paper we investigate the electromagnetic heating in multiple cavities that were designed at Fermilab exploring how the electromagnetic and thermal analyses are coupled together to properly design the cooling of such cavities.

  13. Triangular nanobeam photonic cavities in single crystal diamond

    OpenAIRE

    Bayn, Igal; Meyler, Boris; Salzman, Joseph; Kalish, Rafi

    2011-01-01

    Diamond photonics provides an attractive architecture to explore room temperature cavity quantum electrodynamics and to realize scalable multi-qubit computing. Here we review the present state of diamond photonic technology. The design, fabrication and characterization of a novel triangular cross section nanobeam cavity produced in a single crystal diamond is demonstrated. The present cavity design, based on a triangular cross section allows vertical confinement and better signal collection e...

  14. Damping of the hom's in a multicell superconducting cavity

    International Nuclear Information System (INIS)

    The damping of higher order modes (HOM) was studied for the design of a recirculating linac with superconducting cavities. Measurements on a large iris aperture 5 cell copper cavity equipped with two coaxial HOM couplers, designed for the 1.5 GHz accelerating mode are reported. A cavity design with a smaller number of cells and iris diameters, associated with simpler couplers, resulting in a better optimization for HOM damping and the fundamental mode parameters, is proposed

  15. Quantum superdense coding via cavity-assisted interactions

    International Nuclear Information System (INIS)

    Quantum superdense coding (QSC) is an example of how entanglement can be used to minimize the number of carriers of classical information. This paper proposes two schemes for implementing QSC by means of cavity assisted interactions with single-photon pulses. The schemes are insensitive to the cavity decay and the thermal field, thus it might be realizable based on the current cavity QED techniques

  16. Scalable photonic quantum computation through cavity-assisted interaction

    CERN Document Server

    Duan, L M

    2003-01-01

    We propose a scheme for scalable photonic quantum computation based on cavity assisted interaction between single-photon pulses. The prototypical quantum controlled phase-flip gate between the single-photon pulses is achieved by successively reflecting them from an optical cavity with a single-trapped atom. Our proposed protocol is shown to be robust to practical nose and experimental imperfections in current cavity-QED setups.

  17. The subperitoneal space and peritoneal cavity: basic concepts

    OpenAIRE

    Harpreet K. Pannu; Oliphant, Michael

    2015-01-01

    The subperitoneal space and peritoneal cavity are two mutually exclusive spaces that are separated by the peritoneum. Each is a single continuous space with interconnected regions. Disease can spread either within the subperitoneal space or within the peritoneal cavity to distant sites in the abdomen and pelvis via these interconnecting pathways. Disease can also cross the peritoneum to spread from the subperitoneal space to the peritoneal cavity or vice versa.

  18. Oral cavity metastasis: An unusual presentation of carcinoma prostate

    OpenAIRE

    Damodaran, Dileep; Kathiresan, N.; Satheesan, B.

    2008-01-01

    Oral cavity cancers form the third most common cancers among men in south India. The oral cavity is a very rare site for metastases and has been described in various cancers, particularly lung, breast, kidney and colon carcinoma. Here a very rare case of a buccal metastasis from prostate carcinoma that was originally evaluated as a primary oral cavity malignancy is presented. Histopathological examination of a biopsy of the lesion revealed papillary adenocarcinoma Grade II, nuclear Grade II, ...

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

    Energy Technology Data Exchange (ETDEWEB)

    Kamada, Masaki; Mori, Michiya; Sugawara, Kazuyoshi; Yamada, Yoko; Kurihara, Kazuteru; Shirasaka, Haruki; Nishiguchi, Takashi; Ando, Ritoku; Kamada, Keiichi [Kanazawa Univ., Faculty of Science, Dept. of Physics, Kanazawa, Ishikawa (Japan)

    2002-06-01

    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)

  20. Compensation of the Crossing Angle with Crab Cavities at KEKB

    CERN Document Server

    Abe, T; Akemoto, M; Akiyama, A; Arinaga, M; Ebihara, K; Egawa, K; Enomoto, A; Flanagan, J; Fukuda, S; Fukuma, H; Funakoshi, Y; Furukawa, K; Furuya, T; Hara, K; Higo, T; Hiramatsu, S; Hisamatsu, H; Honma, H; Honma, T; Hosoyama, K; Ieiri, T; Iida, N; Ikeda, H; Ikeda, M; Inagaki, S; Isagawa, S; Ishii, H; Kabe, A; Kadokura, E; Kageyama, T; Kakihara, K; Kako, E; Kamada, S; Kamitani, T; Kanazawa, K; Katagiri, H; Kato, S; Kawamoto, T; Kazakov, S; Kikuchi, M; Kikutani, E; Kitagawa, K; Koiso, H; Kojima, Y; Komada, I; Kubo, T; Kudo, K; Kudo, N; Marutsuka, K; Masuzawa, M; Matsumoto, S; Matsumoto, T; Michizono, S; Mikawa, K; Mimashi, T; Mitsunobu, S; Mori, K; Morita, A; Morita, Y; Nakai, H; Nakajima, H; Nakamura, T T; Nakanishi, H; Nakanishi, K; Nakao, K; Ninomiya, S; Ogawa, Y; Ohmi, K; Ohsawa, S; Ohsawa, Y; Ohnishi, Y; Ohuchi, N; Oide, K; Ono, M; Ozaki, T; Saitô, K; Sakai, H; Sakamoto, Y; Sato, M; Satoh, M; Shibata, K; Shidara, T; Shirai, M; Shirakawa, A; Sueno, T; Suetake, M; Suetsugu, Y; Sugahara, R; Sugimura, T; Suwada, T; Tajima, O; Takano, S; Takasaki, S; Takenaka, T; Takeuchi, Y; Tawada, M; Tejima, M; Tobiyama, M; Tokuda, N; Uehara, S; Uno, S; Yamamoto, Y; Yano, Y; Yokoyama, K; Yoshida, Ma; Yoshida, Mi; Yoshimoto, S; Yoshino, K; Perevedentsev, E; Shatilov, D N

    2007-01-01

    Crab cavities have been installed in the KEKB B--Factory rings to compensate the crossing angle at the collision point and thus increase luminosity. The beam operation with crab crossing has been done since February 2007. This is the first experience with such cavities in colliders or storage rings. The crab cavities have been working without serious issues. While higher specific luminosity than the geometrical gain has been achieved, further study is necessary and under way to reach the prediction of simulation.