Science.gov

Sample records for nine-cell tesla cavity

  1. Wakefield and RF Kicks Due to Coupler Asymmetry in TESLA-Type Accelerating Cavities

    SciTech Connect

    Bane, K.L.F.; Adolphsen, C.; Li, Z.; Dohlus, M.; Zagorodnov, I.; Gonin, I.; Lunin, A.; Solyak, N.; Yakovlev, V.; Gjonaj, E.; Weiland, T.; /Darmstadt, Tech. Hochsch.

    2008-07-07

    In a future linear collider, such as the International Linear Collider (ILC), trains of high current, low emittance bunches will be accelerated in a linac before colliding at the interaction point. Asymmetries in the accelerating cavities of the linac will generate fields that will kick the beam transversely and degrade the beam emittance and thus the collider performance. In the main linac of the ILC, which is filled with TESLA-type superconducting cavities, it is the fundamental (FM) and higher mode (HM) couplers that are asymmetric and thus the source of such kicks. The kicks are of two types: one, due to (the asymmetry in) the fundamental RF fields and the other, due to transverse wakefields that are generated by the beam even when it is on axis. In this report we calculate the strength of these kicks and estimate their effect on the ILC beam. The TESLA cavity comprises nine cells, one HM coupler in the upstream end, and one (identical, though rotated) HM coupler and one FM coupler in the downstream end (for their shapes and location see Figs. 1, 2) [1]. The cavity is 1.1 m long, the iris radius 35 mm, and the coupler beam pipe radius 39 mm. Note that the couplers reach closer to the axis than the irises, down to a distance of 30 mm.

  2. Hydroforming of Tesla Cavities at Desy

    SciTech Connect

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

    2000-07-01

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

  3. Note on the SC Linear Collider TESLA Cavity Design

    NASA Astrophysics Data System (ADS)

    Sekutowicz, J.; Proch, D.; Tang, C.

    1997-05-01

    The experience we have gained over the last few years from experiments with superconducting cavities for the TESLA test facility justifies a revision of the design decided almost five years ago. The proposed new design takes advantage of the high quality factor Q0 > 10^10 and the low electron emission as demonstrated by some tested cavities. The main aim of the new design is to simplify the production and preparation of sc cavities and thus to reduce the cost of the linear collider. The new cavity shape has an enlarged iris diameter with the following advantages: significant lower loss factors, simplified and less expensive scheme for the HOM damping, suitability of hydroforming and higher stability of the field profile.

  4. A Single Crystal Niobium RF Cavity of the TESLA Shape

    SciTech Connect

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

    2007-08-09

    A fabrication method for single crystal niobium cavities of the TESLA shape was proposed on the basis of metallographic investigations and electron beam welding tests on niobium single crystals. These tests showed that a cavity can be produced without grain boundaries even in the welding area. An appropriate annealing allows the outgassing of hydrogen and stress relaxation of the material without destruction of the single crystal. A prototype single crystal single cell cavity was build. An accelerating gradient of 37.5 MV/m was reached after approximately 110 {mu}m of Buffered Chemical Polishing (BCP) and in situ baking at 120 deg. C for 6 hrs with a quality factor exceeding 2x1010 at 1.8 K. The developed fabrication method can be extended to fabrication of multi cell cavities.

  5. A Single Crystal Niobium RF Cavity of the TESLA Shape

    SciTech Connect

    W. Singer; X. Singer; P. Kneisel

    2007-09-01

    A fabrication method for single crystal niobium cavities of the TESLA shape was proposed on the basis of metallographic investigations and electron beam welding tests on niobium single crystals. These tests showed that a cavity can be produced without grain boundaries even in the welding area. An appropriate annealing allows the outgassing of hydrogen and stress relaxation of the material without destruction of the single crystal. A prototype single crystal single cell cavity was built. An accelerating gradient of 37.5 MV/m was reached after approximately 110 mu-m of Buffered Chanical Polishing (BCP) and in situ baking at 120°C for 6 hrs with a quality factor exceeding 2x1010 at 1.8 K. The developed fabrication method can be extended to fabrication of multi cell cavities.

  6. Coaxial Coupling Scheme for TESLA/ILC-type Cavities

    SciTech Connect

    J.K. Sekutowicz, P. Kneisel

    2010-05-01

    This paper reports about our efforts to develop a flangeable coaxial coupler for both HOM and fundamental coupling for 9-cell TESLA/ILC-type cavities. The cavities were designed in early 90‘s for pulsed operation with a low duty factor, less than 1 %. The proposed design of the coupler has been done in a way, that the magnetic flux B at the flange connection is minimized and only a field of <5 mT would be present at the accelerating field Eacc of ~ 36 MV/m (B =150 mT in the cavity). Even though we achieved reasonably high Q-values at low field, the cavity/coupler combination was limited in the cw mode to only ~ 7 MV/m, where a thermally initiated degradation occurred. We have improved the cooling conditions by initially drilling radial channels every 30 degrees, then every 15 degrees into the shorting plate. The modified prototype performed well up to 9 MV/m in cw mode. This paper reports about our experiences with the further modified coaxial coupler and about test results in cw and low duty cycle pulsed mode, similar to the TESLA/ILC operation conditions.

  7. MEASUREMENT OF THE TRANSVERSE BEAM DYNAMICS IN A TESLA-TYPE SUPERCONDUCTING CAVITY

    SciTech Connect

    Halavanau, A.; Eddy, N.; Edstrom, D.; Lunin, A.; Piot, P.; Ruan, J.; Solyak, N.

    2016-09-26

    Superconducting linacs are capable of producing intense, ultra-stable, high-quality electron beams that have widespread applications in Science and Industry. Many project are based on the 1.3-GHz TESLA-type superconducting cavity. In this paper we provide an update on a recent experiment aimed at measuring the transfer matrix of a TESLA cavity at the Fermilab Accelerator Science and Technology (FAST) facility. The results are discussed and compared with analytical and numerical simulations.

  8. Preliminary Measurement of the Transfer Matrix of a TESLA-type Cavity at FAST

    SciTech Connect

    Halavanau, Aliaksei; Eddy, Nathan; Edstrom, Dean; Lunin, Andrei; Piot, Philippe; Ruan, Jinhao; Santucci, James; Solyak, Nikolay

    2016-06-01

    Superconducting linacs are capable of producing intense, ultra-stable, high-quality electron beams that have widespread application in Science and Industry. Many current and planned projects employ 1.3-GHz 9-cell superconducting cavities of the TESLA design*. In the present paper we discuss the transverse-focusing properties of such a cavity and non-ideal transverse-map effects introduced by field asymmetries in the vicinity of the input and high-order-mode radiofrequency (RF) couplers**. We especially consider the case of a cavity located downstream of an RF-gun in a setup similar to the photoinjector of the Fermilab Accelerator Science and Technology (FAST) facility. Preliminary experimental measurements of the CC2 cavity transverse matrix were carried out at the FAST facility. The results are discussed and compared with analytical and numerical simulations.

  9. Steering and focusing effects in TESLA cavity due to high order mode and input couplers

    SciTech Connect

    Piot, P.; Dohlus, M.; Flottmann, K.; Marx, M.; Wipf, S.G.; /DESY

    2005-05-01

    Many state-of-art electron accelerator proposals incorporate TESLA-type superconducting radio-frequency (rf) cavities [1]. These standing wave rf cavities include rf input couplers and a pair of high order mode (HOM) couplers to absorb the energy associated to HOM field excited as the bunch passes through the cavity. In the present paper we investigate, using numerical simulations, the impact of the input and HOM couplers on the beam dynamics to zeroth and first order in initial position, and present parametric studies of the strength of these effects for various incoming beam energies. We finally study the impact of this asymmetric field on the beam dynamics, taking as an example the low energy section of the X-ray FEL injector.

  10. Design, performance and production of the Fermilab TESLA RF input couplers

    SciTech Connect

    Champion, M.

    1996-10-01

    The TeV Energy Superconducting Linear Accelerator (TESLA) requires as one of its technical components a radiofrequency (rf) input coupler that transfers 1.3 GHz rf energy from the rf distribution system to a nine-cell superconducting accelerating cavity operating at a temperature of 1.8 K. The input coupler design is driven by numerous design criteria, which result in a rather complicated implementation. The production of twelve input couplers for the TESLA Test Facility (TTF) is underway at Fermilab, with the first two couplers having been delivered late in 1995. This paper discusses the Fermilab TESLA rf input coupler design, recent test results, and production issues.

  11. Cold RF test and associated mechanical features correlation of a TESLA-style 9-cell superconducting niobium cavity built in China

    SciTech Connect

    Dai, Jing; Quan, Sheng-Wen; Zhang, Bao-Cheng; Lin, Lin; Hao, Jian-Kui; Zhu, Feng; Xu, Wen-Can; He, Fei-Si; Jin, Song; Wang, Fang; Liu, Ke-Xin; Geng, R L; Zhao, Kui

    2012-02-01

    The RF performance of a 1.3 GHz 9-cell superconducting niobium cavity was evaluated at cryogenic temperatures following surface processing by using the standard ILC-style recipe. The cavity is a TESLA-style 9-cell superconducting niobium cavity, with complete end group components including a higher order mode coupler, built in China for practical applications. An accelerating gradient of 28.6 MV/m was achieved at an unloaded quality factor of 4 x 10{sup 9}. The morphological property of mechanical features on the RF surface of this cavity was characterized through optical inspection. Correlation between the observed mechanical features and the RF performance of the cavity is attempted.

  12. Hydroforming of elliptical cavities

    NASA Astrophysics Data System (ADS)

    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

  13. Hydroforming of elliptical cavities

    DOE PAGES

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

    2015-02-27

    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 resultsmore » 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

  14. Hydroforming of elliptical cavities

    SciTech Connect

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

    2015-02-27

    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

  15. Photon collider at TESLA

    NASA Astrophysics Data System (ADS)

    Telnov, Valery

    2001-10-01

    High energy photon colliders ( γγ, γe) based on backward Compton scattering of laser light is a very natural addition to e +e - linear colliders. In this report, we consider this option for the TESLA project. Recent study has shown that the horizontal emittance in the TESLA damping ring can be further decreased by a factor of four. In this case, the γγ luminosity in the high energy part of spectrum can reach about (1/3) Le +e -. Typical cross-sections of interesting processes in γγ collisions are higher than those in e +e - collisions by about one order of magnitude, so the number of events in γγ collisions will be more than that in e +e - collisions. Photon colliders can, certainly, give additional information and they are the best for the study of many phenomena. The main question is now the technical feasibility. The key new element in photon colliders is a very powerful laser system. An external optical cavity is a promising approach for the TESLA project. A free electron laser is another option. However, a more straightforward solution is "an optical storage ring (optical trap)" with a diode pumped solid state laser injector which is today technically feasible. This paper briefly reviews the status of a photon collider based on the linear collider TESLA, its possible parameters and existing problems.

  16. TESLA & ILC Cryomodules

    SciTech Connect

    Peterson, T. J.; Weisend, II, J. G.

    2016-01-01

    The TESLA collaboration developed a unique variant of SRF cryomodule designs, the chief feature being use of the large, low pressure helium vapor return pipe as the structural support backbone of the cryomodule. Additional innovative features include all cryogenic piping within the cryomodule (no parallel external cryogenic transfer line), long strings of RF cavities within a single cryomodule, and cryomodules connected in series. Several projects, including FLASH and XFEL at DESY, LCLS-II at SLAC, and the ILC technical design have adopted this general design concept. Advantages include saving space by eliminating the external transfer line, relatively tight packing of RF cavities along the beamline due to fewer warm-cold transitions, and potentially lower costs. However, a primary disadvantage is the relative lack of independence for warm-up, replacement, and cool-down of individual cryomodules.

  17. Cavity Alighment Using Beam Induced Higher Order Modes Signals in the TTF Linac

    SciTech Connect

    Ross, M.; Frisch, J.; Hacker, K.E.; Jones, R.M.; McCormick, D.; O'Connell, C.; Smith, T.; Napoly, O.; Paparella, R.; Baboi, N.; Wendt, M.; /DESY

    2005-07-06

    Each nine cell superconducting (SC) accelerator cavity in the TESLA Test Facility (TTF) at DESY [1] has two higher order mode (HOM) couplers that efficiently remove the HOM power [2]. They can also provide useful diagnostic signals. The most interesting modes are in the first 2 cavity dipole passbands. They are easy to identify and their amplitude depends linearly on the beam offset from the cavity axis making them excellent beam position monitors (BPM). By steering the beam through an eight-cavity cryomodule, we can use the HOM signals to estimate internal residual alignment errors and minimize wakefield related beam emittance growth. We built and tested a time-domain based waveform recorder system that captures information from each mode in these two bands on each beam pulse. In this paper we present a preliminary experimental study of the single-bunch generated HOM signals at the TTF linac including estimates of cavity alignment precision and HOM BPM resolution.

  18. Report on first TESLA window assembly test

    SciTech Connect

    Sun, D.; Koepke, K.

    1993-10-01

    RF input couplers for the superconducting cavities of the TESLA are under development at DESY and Fermilab. The coaxial part of the Fermilab input coupler has been tested up to 1.7 MW at Fermilab using 805 MHz rf power source. The test results, procedure and test setup are described.

  19. Edison vs. Tesla

    ScienceCinema

    Hogan, Kathleen; Wallace, Hal; Ivestor, Rob

    2016-07-12

    As Edison vs. Tesla week heats up at the Energy Department, we are exploring the rivalry between Thomas Edison and Nikola Tesla and how their work is still impacting the way we use energy today. Whether you're on Team Tesla or Team Edison, both inventors were key players in creating things like batteries, power plants and wireless technologies -- all innovations we still use today. And as we move toward a clean energy future, energy efficient lighting, like LED bulbs, and more efficient electric motors not only help us save money on electricity costs but help combat climate change. For this, Tesla and Edison both deserve our recognition.

  20. Edison vs. Tesla

    SciTech Connect

    Hogan, Kathleen; Wallace, Hal; Ivestor, Rob

    2013-11-20

    As Edison vs. Tesla week heats up at the Energy Department, we are exploring the rivalry between Thomas Edison and Nikola Tesla and how their work is still impacting the way we use energy today. Whether you're on Team Tesla or Team Edison, both inventors were key players in creating things like batteries, power plants and wireless technologies -- all innovations we still use today. And as we move toward a clean energy future, energy efficient lighting, like LED bulbs, and more efficient electric motors not only help us save money on electricity costs but help combat climate change. For this, Tesla and Edison both deserve our recognition.

  1. TESLA Coil Research

    DTIC Science & Technology

    1992-05-01

    Sloan’s work was actually predated by the earlier work of Nikola Tesla . Sloan mistakenly identified " Tesla Coils" as lumped tuned resonators. The...Lefvw WsnJ L REPORT o]i 3. REPRT TYPE AND OATES COVEIRD May 1992 Special/Aug 1992 - May 1992 Z TITLE AND 5U§nUT S. FUNDING NUMIHRS Tesla Coil Research...STATEMENT 1211. ’ISTRIUUTION COOD Approved for public release; dis~ribution is unlimited 13. ABSTRACT (Masrmum 200 worw) High repetition rate Tesla

  2. A laser system for the TESLA photon collider based on an external ring resonator

    NASA Astrophysics Data System (ADS)

    Will, I.; Quast, T.; Redlin, H.; Sandner, W.

    2001-10-01

    We present a concept of a laser system for a photon collider at the TESLA linac. It is based on an external optical ring cavity which is pumped by a short-pulse laser. A detailed discussion of the geometry of the external cavity is given.

  3. [70 years of Nikola Tesla studies].

    PubMed

    Juznic, Stanislav

    2013-01-01

    Nikola Tesla's studies of chemistry are described including his not very scholarly affair in Maribor. After almost a century and half of hypothesis at least usable scenario of Tesla's life and "work" in Maribor is provided. The chemistry achievements of Tesla's most influential professors Martin Sekulić and Tesla's Graz professors are put into the limelight. The fact that Tesla in Graz studied on the technological chemistry Faculty of Polytechnic is focused.

  4. Nikola Tesla: the Moon's rotation.

    NASA Astrophysics Data System (ADS)

    Tomić, A.; Jovanović, B. S.

    1993-09-01

    The review of three articles by N. Tesla, published in the year 1919 in the journal "Electrical experimenter" is given, with special reference to the astronomical contents and to circumstances in which they appeared.

  5. [Nikola Tesla in medicine, too].

    PubMed

    Hanzek, Branko; Jakobović, Zvonimir

    2007-12-01

    Using primary and secondary sources we have shown in this paper the influence of Nikola Tesla's work on the field of medicine. The description of his experiments conduced within secondary-school education programs aimed to present the popularization of his work in Croatia. Although Tesla was dedicated primarily to physics and was not directly involved in biomedical research, his work significantly contributed to paving the way of medical physics particularly radiology and high-frequency electrotherapy.

  6. Report on the TESLA Engineering Study/Review

    SciTech Connect

    Cornuelle, John C.

    2002-08-30

    In March, 2001, the TESLA Collaboration published its Technical Design Report (TDR, see references and links in Appendix), the first sentence of which stated ''...TESLA (TeV-Energy Superconducting Linear Collider) (will be) a superconducting electron-positron collider of initially 500 GeV total energy, extendable to 800 GeV, and an integrated X-ray laser laboratory.'' The TDR included cost and manpower estimates for a 500 GeV e{sup +}e{sup -} collider (250 on 250 GeV) based on superconducting RF cavity technology. This was submitted as a proposal to the German government. The government asked the German Science Council to evaluate this proposal. The recommendation from this body is anticipated to be available by November 2002. The government has indicated that it will react on this recommendation by mid-2003. In June 2001, Steve Holmes, Fermilab's Associate Director for Accelerators, commissioned Helen Edwards and Peter Garbincius to organize a study of the TESLA Technical Design Report and the associated cost and manpower estimates. Since the elements and methodology used in producing the TESLA cost estimate were somewhat different from those used in preparing similar estimates for projects within the U.S., it is important to understand the similarities, differences, and equivalences between the TESLA estimate and U.S. cost estimates. In particular, the project cost estimate includes only purchased equipment, materials, and services, but not manpower from DESY or other TESLA collaborating institutions, which is listed separately. It does not include the R&D on the TESLA Test Facility (TTF) nor the costs of preparing the TDR nor the costs of performing the conceptual studies so far. The manpower for the pre-operations commissioning program (up to beam) is included in the estimate, but not the electrical power or liquid Nitrogen (for initial cooldown of the cryogenics plant). There is no inclusion of any contingency or management reserve. If the U.S. were to become

  7. Adapting TESLA technology for future cw light sources using HoBiCaT

    NASA Astrophysics Data System (ADS)

    Kugeler, O.; Neumann, A.; Anders, W.; Knobloch, J.

    2010-07-01

    The HoBiCaT facility has been set up and operated at the Helmholtz-Zentrum-Berlin and BESSY since 2005. Its purpose is testing superconducting cavities in cw mode of operation and it was successfully demonstrated that TESLA pulsed technology can be used for cw mode of operation with only minor changes. Issues that were addressed comprise of elevated dynamic thermal losses in the cavity walls, necessary modifications in the cryogenics and the cavity processing, the optimum choice of operational parameters such as cavity temperature or bandwidth, the characterization of higher order modes in the cavity, and the usability of existing tuners and couplers for cw.

  8. Electromagnetic SCRF Cavity Tuner

    SciTech Connect

    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.

  9. Nikola Tesla Educational Opportunity School.

    ERIC Educational Resources Information Center

    Design Cost Data, 2001

    2001-01-01

    Describes the architectural design, costs, general description, and square footage data for the Nikola Tesla Educational Opportunity School in Colorado Springs, Colorado. A floor plan and photos are included along with a list of manufacturers and suppliers used for the project. (GR)

  10. A Wire Position Monitor System for the 1.3 FHZ Tesla-Style Cryomodule at the Fermilab New-Muon-Lab Accelerator

    SciTech Connect

    Eddy, N.; Fellenz, B.; Prieto, P.; Semenov, A.; Voy, D.C.; Wendt, M.; /Fermilab

    2011-08-17

    The first cryomodule for the beam test facility at the Fermilab New-Muon-Lab building is currently under RF commissioning. Among other diagnostics systems, the transverse position of the helium gas return pipe with the connected 1.3 GHz SRF accelerating cavities is measured along the {approx}15 m long module using a stretched-wire position monitoring system. An overview of the wire position monitor system technology is given, along with preliminary results taken at the initial module cooldown, and during further testing. As the measurement system offers a high resolution, we also discuss options for use as a vibration detector. An electron beam test facility, based on superconducting RF (SRF) TESLA-style cryomodules is currently under construction at the Fermilab New-Muon-Lab (NML) building. The first, so-called type III+, cryomodule (CM-1), equipped with eight 1.3 GHz nine-cell accelerating cavities was recently cooled down to 2 K, and is currently under RF conditioning. The transverse alignment of the cavity string within the cryomodule is crucial for minimizing transverse kick and beam break-up effects, generated by the high-order dipole modes of misaligned accelerating structures. An optimum alignment can only be guaranteed during the assembly of the cavity string, i.e. at room temperatures. The final position of the cavities after cooldown is uncontrollable, and therefore unknown. A wire position monitoring system (WPM) can help to understand the transverse motion of the cavities during cooldown, their final location and the long term position stability after cryo-temperatures are settled, as well as the position reproducibility for several cold-warm cycles. It also may serve as vibration sensor, as the wire acts as a high-Q resonant detector for mechanical vibrations in the low-audio frequency range. The WPM system consists out of a stretched-wire position detection system, provided with help of INFN-Milano and DESY Hamburg, and RF generation and read

  11. Tesla - A Flash of a Genius

    NASA Astrophysics Data System (ADS)

    Teodorani, M.

    2005-10-01

    This book, which is entirely dedicated to the inventions of scientist Nikola Tesla, is divided into three parts: a) all the most important innovative technological creations from the alternate current to the death ray, Tesla research in fundamental physics with a particular attention to the concept of "ether", ball lightning physics; b) the life and the bright mind of Nikola Tesla and the reasons why some of his most recent findings were not accepted by the establishment; c) a critical discussion of the most important work by Tesla followers.

  12. [Nikola Tesla: flashes of inspiration].

    PubMed

    Villarejo-Galende, Albero; Herrero-San Martín, Alejandro

    2013-01-16

    Nikola Tesla (1856-1943) was one of the greatest inventors in history and a key player in the revolution that led to the large-scale use of electricity. He also made important contributions to such diverse fields as x-rays, remote control, radio, the theory of consciousness or electromagnetism. In his honour, the international unit of magnetic induction was named after him. Yet, his fame is scarce in comparison with that of other inventors of the time, such as Edison, with whom he had several heated arguments. He was a rather odd, reserved person who lived for his inventions, the ideas for which came to him in moments of inspiration. In his autobiography he relates these flashes with a number of neuropsychiatric manifestations, which can be seen to include migraine auras, synaesthesiae, obsessions and compulsions.

  13. A modified post damping ring bunch compressor beamline for the TESLA linear collider

    SciTech Connect

    Philippe R.-G. Piot; Winfried Decking

    2004-03-23

    We propose a modified bunch compressor beamline, downstream of the damping ring, for the TESLA linear collider. This modified beamline uses a third harmonic radio-frequency section based on the 3.9 GHz superconducting cavity under development at Fermilab. In our design the beam deceleration is about {approx}50 MeV instead of {approx}450 MeV in the original design proposed.

  14. Conduction-coupled Tesla transformer.

    PubMed

    Reed, J L

    2015-03-01

    A proof-of-principle Tesla transformer circuit is introduced. The new transformer exhibits the high voltage-high power output signal of shock-excited transformers. The circuit, with specification of proper circuit element values, is capable of obtaining extreme oscillatory voltages. The primary and secondary portions of the circuit communicate solely by conduction. The destructive arcing between the primary and secondary inductors in electromagnetically coupled transformers is ubiquitous. Flashover is eliminated in the new transformer as the high-voltage inductors do not interpenetrate and so do not possess an annular volume of electric field. The inductors are remote from one another. The high voltage secondary inductor is isolated in space, except for a base feed conductor, and obtains earth by its self-capacitance to the surroundings. Governing equations, for the ideal case of no damping, are developed from first principles. Experimental, theoretical, and circuit simulator data are presented for the new transformer. Commercial high-temperature superconductors are discussed as a means to eliminate the counter-intuitive damping due to small primary inductances in both the electromagnetic-coupled and new conduction-coupled transformers.

  15. Science up to 100 tesla

    SciTech Connect

    Campbell, L.J.

    1995-05-01

    100 Tesla is the highest attainable field that can be held for milli-sec in a non-destructive magnet. The strongest steels turn soft under stresses of 4GPa, which is the magnetic pressure of 100 T. Until there is a breakthrough in materials, magnets having all the low temperature and high pressure trimmings will be limited to about 100 T. Within the field range 1-100 T far more resources are now devoted to producing the highest possible continuous fields (40+5 T) than to producing longer pulsed fields above 50 T. This illustrates that the utility of the field can be more important than the strength of the field to researchers in condensed matter. Discoveries are typically made in new territory, but this can be new combinations of pressure, temperature, and magnetic field, or new probes and new materials. If any activity has kept up with the proliferation of new experiments and new facilities in high magnetic field research it is the listing of experiments that could and should be done in high fields. Part of the reason for the vitality of high field research is that high fields provide a generic environment. Compared to particle accelerators and plasma machines a high field laboratory is a setting for generic science, like synchrotron light sources or neutron scattering centers. Although the latter two installations probes states, while a magnetic field creates a state. Because it is unrealistic to try to list all the science opportunities at high fields, the author list sources for lists in the public domain and gives a few examples.

  16. Accelerator aspects of photon colliders at TESLA

    NASA Astrophysics Data System (ADS)

    Walker, Nicholas J.

    2001-10-01

    The TESLA linear collider is being primarily designed as a 500- 800 GeV centre of mass e +e - linear collider. However, a second interaction region is being incorporated into the design with a crossing angle of 32 mrad, which is suitable for use as a γγ collider. In this paper we will review those aspects of the current machine design which are critical to the operation of TESLA as a photon collider, paying particular attention to the preservation of small horizontal emittances, and—in the absence of beamstrahlung—limits on reduced horizontal beam cross-section at the interaction point.

  17. First results of testing 3.9 GHz TM(010) superconducting cavity

    SciTech Connect

    Solyak, N.A.; Bellantoni, L.; Berenc, T.G.; Edwards, H.T.; Gonin, I.V.; Khabiboulline, T.N.; /Fermilab

    2004-10-01

    Fermilab is developing third harmonic 3.9 GHz superconducting cavity to improve performances of A0 and TTF photoinjectors. In frame of this project we have built and tested two nine-cell copper models and one 3-cell niobium cavity. Properties of the high order modes were carefully studied in a chain of two copper cavities at room temperature. In paper we discuss results of cold tests of the 3-cell cavity before and after BCP.

  18. Nikola Tesla, the Ether and his Telautomaton

    NASA Astrophysics Data System (ADS)

    Milar, Kendall

    2014-03-01

    In the nineteenth century physicists' understanding of the ether changed dramatically. New developments in thermodynamics, energy physics, and electricity and magnetism dictated new properties of the ether. These have traditionally been examined from the perspective of the scientists re-conceptualizing the ether. However Nikola Tesla, a prolific inventor and writer, presents a different picture of nineteenth century physics. Alongside the displays that showcased his inventions he presented alternative interpretations of physical, physiological and even psychical research. This is particularly evident in his telautomaton, a radio remote controlled boat. This invention and Tesla's descriptions of it showcase some of his novel interpretations of physical theories. He offered a perspective on nineteenth century physics that focused on practical application instead of experiment. Sometimes the understanding of physical theories that Tesla reached was counterproductive to his own inventive work; other times he offered new insights. Tesla's utilitarian interpretation of physical theories suggests a more scientifically curious and invested inventor than previously described and a connection between the scientific and inventive communities.

  19. Feasibility Study of a HOM IOT for TESLA

    NASA Astrophysics Data System (ADS)

    Schütt, Petra; Weiland, Thomas; Gamp, Alexander; Lu, Fuhai

    1997-05-01

    For the TESLA linear collider 1.3 GHz RF sources with 10 MW peak power and about 70% efficiency are needed. As an alternative to the development of a Multibeam-Klystron, we investigate the feasibility of an IOT (Inductive Output Tube). This is a very compact RF source: The time structure of the beam is produced by a gated emission cathode and the output cavity is directly adjacent to the anode. Unlike IOTs, conventional klystrons lose some of their design efficiency when they are operated below saturation, because only the RF component of the beam is reduced and not the DC beam current. In contrast to this the cathode current of an IOT is controlled by the drive power. In order to keep the gun voltage low, we investigate a device with a hollow beam where the output cavity is excited in a higher order mode (HOM), as was recently suggested by CPI(E.Lien, H.Bohlen, US Patent Application Serial No. 08/413,034). Computer simulations are carried out with the CAD-system MAFIA. First, an existing Klystrode TM IOT built by CPI is analysed. Simulation results will be shown and compared to experimental data. Based upon this experience, a design strategy is discussed for the HOM IOT.

  20. Performance of Single Crystal Niobium Cavities

    SciTech Connect

    Kneisel, Peter; Ciovati, Gianluigi; Singer, Waldemar; Singer, Xenia; Reschke, Detlef; Brinkmann, A.

    2008-07-01

    We have fabricated and tested a total of six single cell niobium cavities, made from single crystal, high purity niobium. Two of the three cavities of the TESLA shape (1300 MHz) were made from Heraeus niobium by extending a smaller single crystal by rolling and annealing steps; the third cavity was made by spinning from CBMM material. The three other cavities of the scaled "Low Loss" (LL) shape (two) and "High Gradient" (HG) shape (one) resonated at 2.3 GHz and were fabricated from "as received" single crystals, both from Heraeus and CBMM niobium. After appropriate surface treatments by buffered chemical polishing and electropolishing most cavities performed quite nicely and peak surface magnetic fields of ~ 160 mT or above corresponding to accelerating gradients between 38 MV/m and 45 MV/m were reached. This paper reports about the performance of these cavities.

  1. Design and scaling of microscale Tesla turbines

    NASA Astrophysics Data System (ADS)

    Krishnan, Vedavalli G.; Romanin, Vince; Carey, Van P.; Maharbiz, Michel M.

    2013-12-01

    We report on the scaling properties and loss mechanisms of Tesla turbines and provide design recommendations for scaling such turbines to the millimeter scale. Specifically, we provide design, fabrication and experimental data for a low-pressure head hydro Tesla micro-turbine. We derive the analytical turbine performance for incompressible flow and then develop a more detailed model that predicts experimental performance by including a variety of loss mechanisms. We report the correlation between them and the experimental results. Turbines with 1 cm rotors, 36% peak efficiency (at 2 cm3 s-1 flow) and 45 mW unloaded peak power (at 12 cm3 s-1 flow) are demonstrated. We analyze the causes for head loss and shaft power loss and derive constraints on turbine design. We then analyze the effect of scaling down on turbine efficiency, power density and rotor revolutions/min. Based on the analysis, we make recommendations for the design of ˜1 mm microscale Tesla turbines.

  2. 76 FR 60124 - Tesla Motors, Inc.; Grant of Petition for Temporary Exemption From the Electronic Stability...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-28

    ... TRANSPORTATION National Highway Traffic Safety Administration Tesla Motors, Inc.; Grant of Petition for Temporary... Stability Control Systems. SUMMARY: This notice grants the petition of Tesla Motors, Inc. (Tesla) for the....S.C. 30113 and the procedures in 49 CFR Part 555, Tesla Motors, Inc. (Tesla) submitted a...

  3. Performance of 3-cell Seamless Niobium cavities

    SciTech Connect

    Kneisel, Peter K.; Ciovati, Gianluigi; Jelezov, I.; Singer, W.; Singer, X.

    2009-11-01

    In the last several months we have surface treated and cryogenically tested three TESLA-type 3-cell cavities, which had been manufactured at DESY as seamless assemblies by hydroforming. The cavities were completed at JLab with beam tube/flange assemblies. All three cavities performed very well after they had been post-purified with titanium at 1250C for 3 hrs. The cavities, two of which consisted of an end cell and 2 center cells and one was a center cell assembly, achieved gradients of Eacc = 32 MV/m, 34 MV/m and 35 MV/m without quenches. The performance was limited by the appearance of the “Q-drop” in the absence of field emission. This contribution reports about the various measurements undertaken with these cavities.

  4. Design of half-reentrant SRF cavities

    NASA Astrophysics Data System (ADS)

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

    2006-07-01

    The shape of a TeSLA inner cell can be improved to lower the peak surface magnetic field at the expense of a higher peak surface electric field by making the cell reentrant. Such a single-cell cavity was designed and tested at Cornell, setting a world record accelerating gradient [V. Shemelin et al., An optimized shape cavity for TESLA: concept and fabrication, 11th Workshop on RF Superconductivity, Travemünde, Germany, September 8-12, 2003; R. Geng, H. Padamsee, Reentrant cavity and first test result, Pushing the Limits of RF Superconductivity Workshop, Argonne National Laboratory, September 22-24, 2004]. However, the disadvantage to a cavity is that liquids become trapped in the reentrant portion when it is vertically hung during high pressure rinsing. While this was overcome for Cornell’s single-cell cavity by flipping it several times between high pressure rinse cycles, this may not be feasible for a multi-cell cavity. One solution to this problem is to make the cavity reentrant on only one side, leaving the opposite wall angle at six degrees for fluid drainage. This idea was first presented in 2004 [T.L. Grimm et al., IEEE Transactions on Applied Superconductivity 15(6) (2005) 2393]. Preliminary designs of two new half-reentrant (HR) inner cells have since been completed, one at a high cell-to-cell coupling of 2.1% (high- kcc HR) and the other at 1.5% (low- kcc HR). The parameters of a HR cavity are comparable to a fully reentrant cavity, with the added benefit that a HR cavity can be easily cleaned with current technology.

  5. Control System Design for Automatic Cavity Tuning Machines

    SciTech Connect

    Carcagno, R.; Khabiboulline, T.; Kotelnikov, S.; Makulski, A.; Nehring, R.; Nogiec, J.; Ross, M.; Schappert, W.; Goessel, A.; Iversen, J.; Klinke, D.; /DESY

    2009-05-01

    A series of four automatic tuning machines for 9-cell TESLA-type cavities are being developed and fabricated in a collaborative effort among DESY, FNAL, and KEK. These machines are intended to support high-throughput cavity fabrication for construction of large SRF-based accelerator projects. Two of these machines will be delivered to cavity vendors for the tuning of XFEL cavities. The control system for these machines must support a high level of automation adequate for industrial use by non-experts operators. This paper describes the control system hardware and software design for these machines.

  6. Jakob Narkiewicz-Jodko-Tesla ``Predecessor''

    NASA Astrophysics Data System (ADS)

    Samuilov, Vladimir; Kiselev, Vladimir

    2014-03-01

    Prof. Jakob Narkiewicz-Jodko (1947-1905) is a bright figure in the history of science of the XIXth century. His major discoveries are: Electrography - the method of the visualization of electric discharge from the bodies due to the application of high strength and high frequency electric fields, and one of the first observations of the propagation of the electromagnetic waives and information transfer over the distances. We review Prof. Jakob Narkiewicz-Jodko's research results and explain our point why we consider him as the predecessor of Nikola Tesla.

  7. First Operating Experiences of Beam Position Monitors in the TESLA Test Facility Linac

    NASA Astrophysics Data System (ADS)

    Lorenz, R.; Sachwitz, M.; Schreiber, H. J.; Tonisch, F.; Castellano, M.; Patteri, P.; Tazzioli, F.; Catani, L.

    1997-05-01

    Different types of monitors where installed in the TESLA Test Facility Linac to measure the beam position. At each superconducting quadrupole, the transverse beam position will be measured with a resolution of better than 10 μm, using a cylindrical cavity excited in the TM_110-mode by an off-center beam. In addition, two 'warm' cavities working at room temperature were built for the Injector I and the Bunch Compressor. The amplitude of the TM_110-mode and its phase are measured in a homodyne receiver. For the experimental area, stripline monitors having a resolution of better than 100 μm were built, tested and installed. The averaged position of the whole bunch train of Injector I is measured in a narrowband receiver using the amplitude-to-phase conversion. This paper summarizes the designs, cold tests and first operating experiences of both monitor types.

  8. Neuromagnetic effects of pico-Tesla stimulation.

    PubMed

    Troebinger, Luzia; Anninos, Photios; Barnes, Gareth

    2015-09-01

    We used a double-blind experimental design to look for an effect of pico-Tesla magnetic stimulation in healthy subjects. Pico-Tesla stimulation is thought to increase the dominant frequency of 2-7 Hz oscillations in the human brain. We used magnetoencephalography to measure resting state brain activity. Each subject had two separate recording sessions consisting of three runs in between which they were given real or sham pT stimulation. We then tried to predict the real and sham stimulation sessions based on changes in the mean peak frequency in the 2-7 Hz band. Our predictions for these individual runs were 8 out of 14 at chance level (p = 0.39). After unblinding, we found no significant effect (p = 0.11) of an increase in the frequency range (2-7 Hz) across the subject group. Finally, we performed a Bayesian model comparison between the effect size predicted from previous clinical studies and a null model. Even though this study had a sensitivity advantage of at least one order of magnitude over previous work, we found the null model to be significantly (2000 times) more likely.

  9. Quantitative techniques for musculoskeletal MRI at 7 Tesla.

    PubMed

    Bangerter, Neal K; Taylor, Meredith D; Tarbox, Grayson J; Palmer, Antony J; Park, Daniel J

    2016-12-01

    Whole-body 7 Tesla MRI scanners have been approved solely for research since they appeared on the market over 10 years ago, but may soon be approved for selected clinical neurological and musculoskeletal applications in both the EU and the United States. There has been considerable research work on musculoskeletal applications at 7 Tesla over the past decade, including techniques for ultra-high resolution morphological imaging, 3D T2 and T2* mapping, ultra-short TE applications, diffusion tensor imaging of cartilage, and several techniques for assessing proteoglycan content in cartilage. Most of this work has been done in the knee or other extremities, due to technical difficulties associated with scanning areas such as the hip and torso at 7 Tesla. In this manuscript, we first provide some technical context for 7 Tesla imaging, including challenges and potential advantages. We then review the major quantitative MRI techniques being applied to musculoskeletal applications on 7 Tesla whole-body systems.

  10. Nikola Tesla: the man behind the magnetic field unit.

    PubMed

    Roguin, Ariel

    2004-03-01

    The magnetic field strength of both the magnet and gradient coils used in MR imaging equipment is measured in Tesla units, which are named for Nikola Tesla. This article presents the life and achievements of this Serbian-American inventor and researcher who discovered the rotating magnetic field, the basis of most alternating-current machinery. Nikola Tesla had 700 patents in the United States and Europe that covered every aspect of science and technology. Tesla's discoveries include the Tesla coil, AC electrical conduction, improved lighting, newer forms of turbine engines, robotics, fluorescent light, wireless transmission of electrical energy, radio, remote control, discovery of cosmic radio waves, and the use of the ionosphere for scientific purposes. He was a genius whose discoveries had a pivotal role in advancing us into the modern era.

  11. Recent Progress of RF Cavity Study at Mucool Test Area

    SciTech Connect

    Yonehara, Katsuya; /Fermilab

    2011-12-02

    Summar of presentation is: (1) MTA is a multi task working space to investigate RF cavities for R&D of muon beam cooling channel - (a) Intense 400 MeV H{sup -} beam, (b) Handle hydrogen (flammable) gas, (c) 5 Tesla SC solenoid magnet, (d) He cryogenic/recycling system; (2) Pillbox cavity has been refurbished to search better RF material - Beryllium button test will be happened soon; (3) E x B effect has been tested in a box cavity - Under study (result seems not to be desirable); (4) 201 MHz RF cavity with SRF cavity treatment has been tested at low magnetic field - (a) Observed some B field effect on maximum field gradient and (b) Further study is needed (large bore SC magnet will be delivered end of 2011); and (5) HPRF cavity beam test has started - (a) No RF breakdown observed and (b) Design a new HPRF cavity to investigate more plasma loading effect.

  12. Optimization of the Low Loss SRF Cavity for the ILC

    SciTech Connect

    Sekutowicz, J.S.; Kneisel, P.; Higo, T.; Morozumi, Y.; Saito, K.; Ge, L.; Ko, Yong-kyu; Lee, L.; Li, Z.; Ng, C.K.; Schussman, G.L.; Xiao, L.; /SLAC

    2008-01-18

    The Low-Loss shape cavity design has been proposed as a possible alternative to the baseline TESLA cavity design for the ILC main linacs. The advantages of this design over the TESLA cavity are its lower cryogenic loss, and higher achievable gradient due to lower surface fields. High gradient prototypes for such designs have been tested at KEK (ICHIRO) and TJNAF (LL). However, issues related to HOM damping and multipacting still need to be addressed. Preliminary numerical studies of the prototype cavities have shown unacceptable damping factors for some higher-order dipole modes if the typical TESLA HOM couplers are directly adapted to the design. The resulting wakefield will dilute the beam emittance thus reducing the machine luminosity. Furthermore, high gradient tests on a 9-cell prototype at KEK have experienced multipacting barriers although a single LL cell had achieved a high gradient. From simulations, multipacting activities are found to occur in the end-groups of the cavity. In this paper, we will present the optimization results of the end-groups for the Low-Loss designs for effective HOM damping and alleviation of multipacting.

  13. Nikola Tesla and the wireless transmission of energy

    SciTech Connect

    Marincic, A.S.

    1982-10-01

    Nikola Tesla, the inventor of the polyphase-current system, is best known for his contribution regarding induction and other types of alternating-current machines. His patents and his published and unpublished notes about wireless transmission of energy are less known and, if known to some extent, they are usually wrongly interpreted. For many years the author studied Tesla's works on wireless transmission of energy and that what is given here is a review of relevant documents, unpublished notes and letters from the archives of the Nikola Tesla Museum in Belgrade. An attempt is made to explain Tesla's physical model on the basis of which he concluded that the wireless transmission of energy on a global scale is possible. His model is critically examined in view of the present day knowledge of extremely low frequency propagation phenomena.

  14. Progress toward 10 tesla accelerator dipoles

    SciTech Connect

    Hassenzahl, W.; Gilbert, G.; Taylor, C.; Meuser, R.

    1983-08-01

    A 9.1 T central field has been achieved in a Nb-Ti dipole operating in pressurized helium II at 1.8 K. Three different Nb-Ti dipoles, without iron yokes, have achieved central fields of 8.0, 8.6, and 9.1 T - all short sample performance for the conductors at 1.8 K. In helium I, at 4.3 K, the maximum central fields are from 1.5 to 2.0 T lower. Ten-tesla magnets have been designed for both Nb-Ti operating at 1.8 K and Nb/sub 3/Sn operating at 4.2 K. They are based on a very small beam aperture, (40 to 45 mm), very high current density in the superconductors (over 1000 A/mm/sup 2/), and a very low ratio of stabilizing copper to superconductor (about 1). Both layer and block designs have been developed that utilize Rutherford Cable. Magnet cycling from 0 to 6 T has been carried out for field change rate up to 1 T/s; the cyclic heating at 1 T/s is 36 W per meter. At a more representative rate of 0.2 T/s the heating rate is only 2 W/m. Progress in the program to use Nb/sub 3/Sn and NbTi superconductor, in 10 T accelerator magnets is also discussed.

  15. Wake fields in 9-cell TESLA accelerating structures : Spectral Element Discontinuous Galerkin (SEDG) simulations.

    SciTech Connect

    Min, M.; Fischer, P. F.; Chae, Y.-C.

    2007-01-01

    Using our recently developed high-order accurate Maxwell solver, NEKCEM, we carried out longitudinal wakefield calculations for a 9-cell TESLA cavity structure in 3D. Indirect method is used for wake potential calculations. Computational results with NEKCEM are compared with those of GdfidL. NEKCEM uses a spectral element discontinuous Galerkin (SEDG) method based on a domain decomposition approach using spectral-element discretizations on Gauss-Lobatto-Legendre grids with body-conforming hexahedral meshes. The numerical scheme is designed to ensure high-order spectral accuracy, using the discontinuous Galerkin form with boundary conditions weakly enforced through a flux term between elements. Concerns related to implementation on wake potential calculations are discussed, and wake potential calculations with indirect method by NEKCEM compared with the results of the finite difference time-domain code GdfidL.

  16. Superconducting cavities for particle accelerators

    NASA Astrophysics Data System (ADS)

    Padamsee, H.

    1992-02-01

    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. Encouraged by this success, another 500 meters of SRF cavities are in the production line. New applications for High Energy Physics are forthcoming for high current e+e- colliders 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.

  17. Quantitative techniques for musculoskeletal MRI at 7 Tesla

    PubMed Central

    Taylor, Meredith D.; Tarbox, Grayson J.; Palmer, Antony J.; Park, Daniel J.

    2016-01-01

    Whole-body 7 Tesla MRI scanners have been approved solely for research since they appeared on the market over 10 years ago, but may soon be approved for selected clinical neurological and musculoskeletal applications in both the EU and the United States. There has been considerable research work on musculoskeletal applications at 7 Tesla over the past decade, including techniques for ultra-high resolution morphological imaging, 3D T2 and T2* mapping, ultra-short TE applications, diffusion tensor imaging of cartilage, and several techniques for assessing proteoglycan content in cartilage. Most of this work has been done in the knee or other extremities, due to technical difficulties associated with scanning areas such as the hip and torso at 7 Tesla. In this manuscript, we first provide some technical context for 7 Tesla imaging, including challenges and potential advantages. We then review the major quantitative MRI techniques being applied to musculoskeletal applications on 7 Tesla whole-body systems. PMID:28090448

  18. Novel High Cooperativity Photon-Magnon Cavity QED

    NASA Astrophysics Data System (ADS)

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

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

  19. [Studies of three-dimensional cardiac late gadolinium enhancement MRI at 3.0 Tesla].

    PubMed

    Ishimoto, Takeshi; Ishihara, Masaru; Ikeda, Takayuki; Kawakami, Momoe

    2008-12-20

    Cardiac late Gadolinium enhancement MR imaging has been shown to allow assessment of myocardial viability in patients with ischemic heart disease. The current standard approach is a 3D inversion recovery sequence at 1.5 Tesla. The aims of this study were to evaluate the technique feasibility and clinical utility of MR viability imaging at 3.0 Tesla in patients with myocardial infarction and cardiomyopathy. In phantom and volunteer studies, the inversion time required to suppress the signal of interests and tissues was prolonged at 3.0 Tesla. In the clinical study, the average inversion time to suppress the signal of myocardium at 3.0 Tesla with respect to MR viability imaging at 1.5 Tesla was at 15 min after the administration of contrast agent (304.0+/-29.2 at 3.0 Tesla vs. 283.9+/-20.9 at 1.5 Tesla). The contrast between infarction and viable myocardium was equal at both field strengths (4.06+/-1.30 at 3.0 Tesla vs. 4.42+/-1.85 at 1.5 Tesla). Even at this early stage, MR viability imaging at 3.0 Tesla provides high quality images in patients with myocardial infarction. The inversion time is significantly prolonged at 3.0 Tesla. The contrast between infarction and viable myocardium at 3.0 Tesla are equal to 1.5 Tesla. Further investigation is needed for this technical improvement, for clinical evaluation, and for limitations.

  20. A Study of Thermocurrent Induced Magnetic Fields in ILC Cavities

    SciTech Connect

    Crawford, Anthony C.; Cooley, Victoria

    2014-03-31

    The case of axisymmetric ILC-type cavities with titanium helium vessels is investigated. A first-order estimate for magnetic field within the SRF current layer is presented. The induced magnetic field is found to be not more than 1.4x10-8 Tesla = 0.14 milligauss for the case of axial symmetry. Magnetic fields due to symmetry breaking effects are discussed.

  1. Cavity magnomechanics

    PubMed Central

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

    2016-01-01

    A dielectric body couples with electromagnetic fields through radiation pressure and electrostrictive forces, which mediate phonon-photon coupling in cavity optomechanics. In a magnetic medium, according to the Korteweg-Helmholtz formula, which describes the electromagnetic force density acting on a medium, magneostrictive forces should arise and lead to phonon-magnon interaction. We report such a coupled phonon-magnon system based on ferrimagnetic spheres, which we term as cavity magnomechanics, by analogy to cavity optomechanics. Coherent phonon-magnon interactions, including electromagnetically induced transparency and absorption, are demonstrated. Because of the strong hybridization of magnon and microwave photon modes and their high tunability, our platform exhibits new features including parametric amplification of magnons and phonons, triple-resonant photon-magnon-phonon coupling, and phonon lasing. Our work demonstrates the fundamental principle of cavity magnomechanics and its application as a new information transduction platform based on coherent coupling between photons, phonons, and magnons. PMID:27034983

  2. Three-dimensional flow measurements in a tesla turbine rotor

    NASA Astrophysics Data System (ADS)

    Fuchs, Thomas; Schosser, Constantin; Hain, Rainer; Kaehler, Christian

    2015-11-01

    Tesla turbines are fluid mechanical devices converting flow energy into rotation energy by two physical effects: friction and adhesion. The advantages of the tesla turbine are its simple and robust design, as well as its scalability, which makes it suitable for custom power supply solutions, and renewable energy applications. To this day, there is a lack of experimental data to validate theoretical studies, and CFD simulations of these turbines. This work presents a comprehensive analysis of the flow through a tesla turbine rotor gap, with a gap height of only 0.5 mm, by means of three-dimensional Particle Tracking Velocimetry (3D-PTV). For laminar flows, the experimental results match the theory very well, since the measured flow profiles show the predicted second order parabolic shape in radial direction and a fourth order behavior in circumferential direction. In addition to these laminar measurements, turbulent flows at higher mass flow rates were investigated.

  3. Challenges for picoTesla Magnetic-Tunnel-Junction Sensors

    NASA Astrophysics Data System (ADS)

    Egelhoff, William; Pong, Philip; McMichael, Robert; Nowak, Edmund; Edelstein, Alan; Burnett, James; Fisher, Greg

    2008-03-01

    The extension of small, inexpensive, low-power, low frequency, ultra-sensitive magnetic sensors to fields between 1 nanoTesla and 1 picoTesla, an area currently dominated by fluxgates, optically-pumped magnetometers, and SQUIDS, would be a paradigm shift for the field of magnetic sensors. The necessary elements for picoTesla MTJ sensors have been identified by modeling the noise characteristics. The results help identify the experimental challenges that exist in the integration of the necessary components of the sensor and illustrate the trade-offs that must be considered. For example, values of the TMR above 100% contribute very little, while lowering the saturation field of the free layer below 10 Oe is essential. These and other insights identify the critical issues than need attention and can guide research into productive directions.

  4. Optic Nerve Assessment Using 7-Tesla Magnetic Resonance Imaging

    PubMed Central

    Singh, Arun D.; Platt, Sean M.; Lystad, Lisa; Lowe, Mark; Oh, Sehong; Jones, Stephen E.; Alzahrani, Yahya; Plesec, Thomas

    2016-01-01

    Purpose The purpose of this study was to correlate high-resolution magnetic resonance imaging (MRI) and histologic findings in a case of juxtapapillary choroidal melanoma with clinical evidence of optic nerve invasion. Methods With institutional review board approval, an enucleated globe with choroidal melanoma and optic nerve invasion was imaged using a 7-tesla MRI followed by histopathologic evaluation. Results Optical coherence tomography, B-scan ultrasonography, and 1.5-tesla MRI of the orbit (1-mm sections) could not detect optic disc invasion. Ex vivo, 7-tesla MRI detected optic nerve invasion, which correlated with histopathologic features. Conclusions Our case demonstrates the potential to document the existence of optic nerve invasion in the presence of an intraocular tumor, a feature that has a major bearing on decision making, particularly for consideration of enucleation. PMID:27239461

  5. Time Synchronization in Hierarchical TESLA Wireless Sensor Networks

    SciTech Connect

    Jason L. Wright; Milos Manic

    2009-08-01

    Time synchronization and event time correlation are important in wireless sensor networks. In particular, time is used to create a sequence events or time line to answer questions of cause and effect. Time is also used as a basis for determining the freshness of received packets and the validity of cryptographic certificates. This paper presents secure method of time synchronization and event time correlation for TESLA-based hierarchical wireless sensor networks. The method demonstrates that events in a TESLA network can be accurately timestamped by adding only a few pieces of data to the existing protocol.

  6. Paul Drude's Prediction of Nonreciprocal Mutual Inductance for Tesla Transformers

    PubMed Central

    McGuyer, Bart

    2014-01-01

    Inductors, transmission lines, and Tesla transformers have been modeled with lumped-element equivalent circuits for over a century. In a well-known paper from 1904, Paul Drude predicts that the mutual inductance for an unloaded Tesla transformer should be nonreciprocal. This historical curiosity is mostly forgotten today, perhaps because it appears incorrect. However, Drude's prediction is shown to be correct for the conditions treated, demonstrating the importance of constraints in deriving equivalent circuits for distributed systems. The predicted nonreciprocity is not fundamental, but instead is an artifact of the misrepresentation of energy by an equivalent circuit. The application to modern equivalent circuits is discussed. PMID:25542040

  7. Investigation of Thermal Acoustic Effects on SRF Cavities within CM1 at Fermilab

    SciTech Connect

    McGee, Mike; Harms, Elvin; Klebaner, Arkadiy; Leibfritz, Jerry; Martinez, Alex; Pischalnikov, Yuriy; Schappert, Warren

    2016-06-01

    Two TESLA-style 8-cavity cryomodules have been operated at Fermilab Accelerator Science and Technology (FAST), formerly the Superconducting Radio Frequency (SRF) Accelerator Test Facility. Operational instabilities were revealed during Radio Frequency (RF) power studies. These observations were complemented by the characterization of thermal acoustic effects on cavity microphonics manifested by apparent noisy boiling of helium involving vapor bubble and liquid vibration. The thermal acoustic measurements also consider pressure and temperature spikes which drive the phenomenon at low and high frequencies.

  8. Overview of high gradient SRF R&D for ILC cavities at Jefferson Lab

    SciTech Connect

    Geng, Rongli

    2009-11-01

    We report the progress on high gradient R&D of ILC cavities at Jefferson Lab (JLab) since the Beijing workshop. Routine 9-cell cavity electropolishing (EP) processing and RF testing has been enhanced with added surface mapping and T-mapping instrumentations. 12 new 9-cell cavities (10 of them are baseline fine-grain TESLA-shape cavities: 5 built by ACCEL/Research Instruments, 4 by AES and 1 by JLab; 2 of them are alternative cavities: 1 fine-grain ICHIRO-shape cavity built by KEK/Japan industry and 1 large-grain TESLA-shape cavity built by JLab) are EP processed and tested. 76 EP cycles are accumulated, corresponding to more than 200 hours of active EP time. Field emission (FE) and quench behaviors of electropolished 9-cell cavities are studied. EP process continues to be optimized, resulting in advanced procedures and hence improved cavity performance. Several 9-cell cavities reached 35 MV/m after the first light EP processing. FE-free performance has been demonstrated in 9-cell cavities in 35-40 MV/m range. 1-cell cavity studies explore new techniques for defect removal as well as advanced integrated cavity processing. Surface studies of niobium samples electropolished together with real cavities provide new insight into the nature of field emitters. Close cooperation with the US cavity fabrication industry has been undertaking with the successful achievement of 41 MV/m for the first time in a 9-cell ILC cavity built by AES. As the size of the data set grows, it is now possible to construct gradient yield curves, from which one can see that significant progress has been made in raising the high gradient yield.

  9. 77 FR 60672 - Grant of Authority for Subzone Status; Tesla Motors, Inc., (Electric Passenger Vehicles), Palo...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-04

    ... Foreign-Trade Zones Board Grant of Authority for Subzone Status; Tesla Motors, Inc., (Electric Passenger... establish a special-purpose subzone at the electric passenger vehicle manufacturing facilities of Tesla... electric passenger vehicles and related powertrain components at the Tesla Motors, Inc., facilities...

  10. Recent progress of RF cavity study at Mucool Test Area

    NASA Astrophysics Data System (ADS)

    Yonehara, Katsuya; MTA working Group

    2013-02-01

    In order to develop an RF cavity that is applicable for a muon beam cooling channel, a new facility, called Mucool Test Area (MTA) has been built at Fermilab. MTA is a unique facility whose purpose is to test RF cavities in various conditions. There are 201 and 805 MHz high power sources, a 4-Tesla solenoid magnet, a cryogenic system including a Helium liquifier, an explosion proof apparatus to operate gaseous/liquid Hydrogen, and a beam transport line to send an intense H- beam from the Fermilab Linac accelerator to the MTA hall. Recent activities at MTA will be discussed in this document.

  11. Individual RF Test Results of the Cavities Used in the First US-built ILC-type Cryomodule

    SciTech Connect

    Hocker, A; Harms, E R; Lunin, A; Sergatskov, D A; Sukhanov, A I; Eremeev, G V; Geng, R L; Ozelis, J P

    2012-07-01

    Eight 1.3-GHz, nine-cell SRF cavities have been installed in a cryomodule intended to demonstrate the ILC design goal of 31.5 MV/m. These cavities all underwent two types of individual RF testing: a low-power continuous-wave test of the 'bare' cavity and a high-power pulsed test of the 'dressed' cavity. Presented here is a discussion of the results from these tests and a comparison of their performance in the two configurations.

  12. Identifying Needed Technical Standards: The LITA TESLA Committee at Work.

    ERIC Educational Resources Information Center

    Carter, Ruth C.

    1984-01-01

    Efforts of the Technical Standards for Library Automation Committee (TESLA), a division-wide committee of the Library Information and Technology Association (LITA) of the American Library Association, are described. The current status of suggested technical standards and recommended action are detailed. Five sources are given. (Author/EJS)

  13. Superconducting cavity material for the European XFEL

    NASA Astrophysics Data System (ADS)

    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.

  14. Development of the third harmonic SC cavity at Fermilab

    SciTech Connect

    Nikolay Solyak et al.

    2004-08-05

    The third harmonic 3.9 GHz superconducting cavity was recently proposed by DESY for a new generation of high brightness photo-injector (TTF photoinjector-2) to compensate nonlinear distortion of the longitudinal phase space due to RF curvature of the 1.3 GHz TESLA cavities [1,2]. Installation of the 3rd harmonic cavity will allow us to generate ultra-short (<50 {micro}m rms) highly charged electron bunches with an extremely small transverse normalized emittance (<1 {micro}m). This is required to support a new generation of linear colliders, free electron lasers and synchrotron radiation sources. In this paper we present the current status of the 3rd harmonic cavity being developed at Fermilab. We discuss the design procedure, the building and testing of the copper and niobium half-cells and components, the design of input and HOM couplers.

  15. Functionality of veterinary identification microchips following low- (0.5 tesla) and high-field (3 tesla) magnetic resonance imaging.

    PubMed

    Piesnack, Susann; Frame, Mairi E; Oechtering, Gerhard; Ludewig, Eberhard

    2013-01-01

    The ability to read patient identification microchips relies on the use of radiofrequency pulses. Since radiofrequency pulses also form an integral part of the magnetic resonance imaging (MRI) process, the possibility of loss of microchip function during MRI scanning is of concern. Previous clinical trials have shown microchip function to be unaffected by MR imaging using a field strength of 1 Tesla and 1.5. As veterinary MRI scanners range widely in field strength, this study was devised to determine whether exposure to lower or higher field strengths than 1 Tesla would affect the function of different types of microchip. In a phantom study, a total of 300 International Standards Organisation (ISO)-approved microchips (100 each of three different types: ISO FDX-B 1.4 × 9 mm, ISO FDX-B 2.12 × 12 mm, ISO HDX 3.8 × 23 mm) were tested in a low field (0.5) and a high field scanner (3.0 Tesla). A total of 50 microchips of each type were tested in each scanner. The phantom was composed of a fluid-filled freezer pack onto which a plastic pillow and a cardboard strip with affixed microchips were positioned. Following an MRI scan protocol simulating a head study, all of the microchips were accurately readable. Neither 0.5 nor 3 Tesla imaging affected microchip function in this study.

  16. 76 FR 33402 - Tesla Motors, Inc.; Receipt of Petition for Renewal of Temporary Exemption from the Advanced Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-08

    ... National Highway Traffic Safety Administration Tesla Motors, Inc.; Receipt of Petition for Renewal of... Part 555, Tesla Motors, Inc., has petitioned the agency for renewal of a temporary exemption from... procedures in 49 CFR Part 555, Tesla Motors, Inc., (Tesla) has submitted a petition asking the agency...

  17. Optimization of the Low-Loss SRF Cavity for the ILC

    SciTech Connect

    Z. Li; L. Ge; K. Ko; L. Lee; C.-K. Ng; G. L. Schussman; L. Xiao; T. Higo; Y. Morozumi; K. Saito; P. Kneisel; J. S. Sekutowicz

    2007-08-01

    The Low-Loss shape cavity design has been proposed as a possible alternative to the baseline TESLA cavity design for the ILC. The advantages of this design over the TESLA cavity are its lower cryogenic loss, and higher achievable gradient due to lower surface fields. High gradient prototypes for such designs have been tested at KEK (ICHIRO) and JLab (LL). However, issues related to HOM damping and multipacting (MP) still need to be addressed. Preliminary numerical studies of the prototype cavities have shown unacceptable damping for some higher-order dipole modes if the typical TESLA HOM couplers are directly adapted to the design. The resulting wakefield will dilute the beam emittance thus reduces the machine luminosity. Furthermore, high gradient tests on a 9-cell prototype at KEK have experienced MP barriers although a single LL cell had achieved a high gradient. From simulations, MP activities are found to occur in the end-groups of the cavity. In this paper, we will present the optimization results of the end-groups for the Low-Loss shape for effective HOM damping and alleviation of multipacting. Comparisons of simulation results with measurements will also be presented.

  18. Multi circular-cavity surface coil for magnetic resonance imaging of monkey's brain at 4 Tesla

    NASA Astrophysics Data System (ADS)

    Osorio, A. I.; Solis-Najera, S. E.; Vázquez, F.; Wang, R. L.; Tomasi, D.; Rodriguez, A. O.

    2014-11-01

    Animal models in medical research has been used to study humans diseases for several decades. The use of different imaging techniques together with different animal models offers a great advantage due to the possibility to study some human pathologies without the necessity of chirurgical intervention. The employ of magnetic resonance imaging for the acquisition of anatomical and functional images is an excellent tool because its noninvasive nature. Dedicated coils to perform magnetic resonance imaging experiments are obligatory due to the improvement on the signal-to-noise ratio and reduced specific absorption ratio. A specifically designed surface coil for magnetic resonance imaging of monkey's brain is proposed based on the multi circular-slot coil. Numerical simulations of the magnetic and electric fields were also performed using the Finite Integration Method to solve Maxwell's equations for this particular coil design and, to study the behavior of various vector magnetic field configurations and specific absorption ratio. Monkey's brain images were then acquired with a research-dedicated magnetic resonance imaging system at 4T, to evaluate the anatomical images with conventional imaging sequences. This coil showed good quality images of a monkey's brain and full compatibility with standard pulse sequences implemented in research-dedicated imager.

  19. A 10 tesla table-top controlled waveform magnet.

    PubMed

    Roy Choudhury, Aditya N; Venkataraman, V

    2012-04-01

    Controlled waveform magnets (CWMs) are a class of pulsed magnets whose pulse shape with time can be programmed by the user. With a CWM, the user gains control not only over the magnitude of the field but also over its rate of change. In this work we present a table-top CWM, driven by a capacitor bank, capable of producing virtually any user-shaped magnetic field waveform up to 10 tesla. Insulated gate bipolar transistor chips have been paralleled to form the high current switch and paralleled chips of SiC Schottky diodes form the crowbar diode module. Sample controlled waveforms including flat-tops up to 10 tesla and some triangular magnetic field pulses have been successfully generated for 10-20 ms with a ripple <1%.

  20. Utilizing Gas Filled Cavities for the Generation of an Intense Muon Source

    SciTech Connect

    Stratakis, Diktys; Neuffer, David V.

    2015-05-01

    A key requirement for designing intense muon sources is operating rf cavities in multi-tesla magnetic fields. Recently, a proof-of-principle experiment demonstrated that an rf cavity filed with high pressure hydrogen gas could meet this goal. In this study, rigorous simulation is used to design and evaluate the performance of an intense muon source with gas filled cavities. We present a new lattice design and compare our results with conventional schemes. We detail the influence of gas pressure on the muon production rate.

  1. Utilizing gas-filled cavities for the generation of an intense muon source

    SciTech Connect

    Stratakis, Diktys; Neuffer, David V.

    2015-05-03

    A key requirement for designing intense muon sources is operating rf cavities in multi-tesla magnetic fields. Recently, a proof-of-principle experiment demonstrated that an rf cavity filed with high pressure hydrogen gas could meet this goal. In this study, rigorous simulation is used to design and evaluate the performance of an intense muon source with gas filled cavities. We present a new lattice design and compare our results with conventional schemes. We detail the influence of gas pressure on the muon production rate.

  2. RF optimization and analysis of the 805-MHz cavity for the MuCool program using ACE3P

    NASA Astrophysics Data System (ADS)

    Li, Zenghai; Ge, Lixin; Adolphsen, Chris; Li, Derun; Bowring, Daniel

    2012-12-01

    An 805 MHz pillbox cavity tested at Fermilab's MTA facility showed significant degradation in gradient when operated in a several Tesla solenoidal magnetic field. We have used the advanced ACE3P simulation codes developed at SLAC to study the cavity dark current and multipacting characteristics to gain more insight into the gradient limitations. We also checked whether there is an optimal cavity length that minimizes the dark current impact energy. Finally, we have improved on the cavity design, significantly lowering the fields outside the beam area. These and other results are presented in this paper.

  3. RF optimization and analysis of the 805-MHz cavity for the MuCool program using ACE3P

    SciTech Connect

    Li Zenghai; Ge Lixin; Adolphsen, Chris; Li Derun; Bowring, Daniel

    2012-12-21

    An 805 MHz pillbox cavity tested at Fermilab's MTA facility showed significant degradation in gradient when operated in a several Tesla solenoidal magnetic field. We have used the advanced ACE3P simulation codes developed at SLAC to study the cavity dark current and multipacting characteristics to gain more insight into the gradient limitations. We also checked whether there is an optimal cavity length that minimizes the dark current impact energy. Finally, we have improved on the cavity design, significantly lowering the fields outside the beam area. These and other results are presented in this paper.

  4. RHQT Nb3Al 15-Tesla magnet design study

    SciTech Connect

    Yamada, R.; Ambrosio, G.; Barzi, E.; Kashikin, V.; Kikuchi, A.; Novitski, I.; Takeuchi, T.; Wake, M.; Zlobin, A.; /Fermilab /NIMC, Tsukuba /KEK, Tsukuba

    2005-09-01

    Feasibility study of 15-Tesla dipole magnets wound with a new copper stabilized RHQT Nb{sub 3}Al Rutherford cable is presented. A new practical long copper stabilized RHQT Nb{sub 3}Al strand is presented, which is being developed and manufactured at the National Institute of Material Science (NIMS) in Japan. It has achieved a non-copper J{sub c} of 1000A/mm{sup 2} at 15 Tesla at 4.2K, with a copper over non-copper ratio of 1.04, and a filament size less than 50 microns. For this design study a short Rutherford cable with 28 Nb{sub 3}Al strands of 1 mm diameter will be fabricated late this year. The cosine theta magnet cross section is designed using ROXIE, and the stress and strain in the coil is estimated and studied with the characteristics of the Nb{sub 3}Al strand. The advantages and disadvantages of the Nb{sub 3}Al cable are compared with the prevailing Nb{sub 3}Sn cable from the point of view of stress-strain, J{sub c}, and possible degradation of stabilizer due to cabling. The Nb{sub 3}Al coil of the magnet, which will be made by wind and react method, has to be heat treated at 800 degree C for 10 hours. As preparation for the 15 Tesla magnet, a series of tests on strand and Rutherford cables are considered.

  5. Multi-purpose 805 MHz Pillbox RF Cavity for Muon Acceleration Studies

    SciTech Connect

    Kurennoy, Sergey S.; Chan, Kwok-Chi Dominic; Jason, Andrew; Miyadera, Haruo; Turchi, Peter J.

    2011-01-01

    An 805 MHz RF pillbox cavity has been designed and constructed to investigate potential muon beam acceleration and cooling techniques. The cavity can operate at vacuum or under pressure to 100 atmospheres, at room temperature or in a liquid nitrogen bath at 77 K. The cavity is designed for easy assembly and disassembly with bolted construction using aluminum seals. The surfaces of the end walls of the cavity can be replaced with different materials such as copper, aluminum, beryllium, or molybdenum, and with different geometries such as shaped windows or grid structures. Different surface treatments such as electro polished, high-pressure water cleaned, and atomic layer deposition are being considered for testing. The cavity has been designed to fit inside the 5-Tesla solenoid in the MuCool Test Area at Fermilab. Current status of the cavity prepared for initial conditioning and operation in the external magnetic field is discussed.

  6. Copper Prototype Measurements of the HOM, LOM And SOM Couplers for the ILC Crab Cavity

    SciTech Connect

    Burt, G.; Ambattu, P.K.; Dexter, A.C.; Bellantoni, L.; Goudket, P.; McIntosh, P.A.; Li, Z.; Xiao, L.; /SLAC

    2011-11-04

    The ILC Crab Cavity is positioned close to the IP and delivered luminosity is very sensitive to the wakefields induced in it by the beam. A set of couplers were designed to couple to and damp the spurious modes of the crab cavity. As the crab cavity operates using a dipole mode, it has different damping requirements from an accelerating cavity. A separate coupler is required for the monopole modes below the operating frequency of 3.9 GHz (known as the LOMs), the opposite polarization of the operating mode (the SOM), and the modes above the operating frequency (the HOMs). Prototypes of each of these couplers have been manufactured out of copper and measured attached to an aluminum nine cell prototype of the cavity and their external Q factors were measured. The results were found to agree well with numerical simulations.

  7. Copper Prototype Measurements of the HOM, LOM and SOM Couplers for the ILC Crab Cavity

    SciTech Connect

    Burt, G.; Ambattu, P.K.; Dexter, A.C.; Bellantoni, L.; Goudket, P.; McIntosh, P.A.; Li, Z.; Xiao, L.; /SLAC

    2008-06-23

    The ILC Crab Cavity is positioned close to the IP and delivered luminosity is very sensitive to the wakefields induced in it by the beam. A set of couplers were designed to couple to and damp the spurious modes of the crab cavity. As the crab cavity operates using a dipole mode, it has different damping requirements from an accelerating cavity. A separate coupler is required for the monopole modes below the operating frequency of 3.9 GHz (known as the LOMs), the opposite polarization of the operating mode (the SOM), and the modes above the operating frequency (the HOMs). Prototypes of each of these couplers have been manufactured out of copper and measured attached to an aluminum nine cell prototype of the cavity and their external Q factors were measured. The results were found to agree well with numerical simulations.

  8. Capture cavity cryomodule for quantum beam experiment at KEK superconducting RF test facility

    NASA Astrophysics Data System (ADS)

    Tsuchiya, K.; Hara, K.; Hayano, H.; Kako, E.; Kojima, Y.; Kondo, Y.; Nakai, H.; Noguchi, S.; Ohuchi, N.; Terashima, A.; Horikoshi, A.; Semba, T.

    2014-01-01

    A capture cavity cryomodule was fabricated and used in a beam line for quantum beam experiments at the Superconducting RF Test Facility (STF) of the High Energy Accelerator Research Organization in Japan. The cryomodule is about 4 m long and contains two nine-cell cavities. The cross section is almost the same as that of the STF cryomodules that were fabricated to develop superconducting RF cavities for the International Linear Collider. An attempt was made to reduce the large deflection of the helium gas return pipe (GRP) that was observed in the STF cryomodules during cool-down and warm-up. This paper briefly describes the structure and cryogenic performance of the captures cavity cryomodule, and also reports the measured displacement of the GRP and the cavity-containing helium vessels during regular operation.

  9. Comments on the New Tesla Electromagnetics. Part I. Discrepancies in Present EM Theory,

    DTIC Science & Technology

    1982-01-01

    new "superrelativity" to describe the expanded electromagnetic reality uncovered by Nikola Tesla . (14) "Charge" is assumed to be quantized, in addition...California, 94030, 1980. The present electromagnetics is just a special case of a much more fundamental electromagnetics discovered by Nikola Tesla , just...AD-RI27 574 COMMENTS ON THE NEW TESLA ELECTROMAGNET ICS PART I L/i DISCREPANCIES IN PRESENT EM THEORY(U) BEARDEN (THOMAS E) HUNTSVILLE AL T E BEARDEN

  10. Exploration of material removal rate of srf elliptical cavities as a function of media type and cavity shape on niobium and copper using centrifugal barrel polishing (cbp)

    SciTech Connect

    Palczewski, Ari; Ciovati, Gianluigi; Li, Yongming; Geng, Rongli

    2013-09-01

    Centrifugal barrel polishing (cbp) for SRF application is becoming more wide spread as the technique for cavity surface preparation. CBP is now being used in some form at SRF laboratories around the world including in the US, Europe and Asia. Before the process can become as mature as wet chemistry like eletro-polishing (EP) and buffered chemical polishing (BCP) there are many questions which remain unanswered. One of these topics includes the uniformity of removal as a function of cavity shape and material type. In this presentation we show CBP removal rates for various media types on 1.3 GHz TESLA and 1.5 GHz CEBAF large/fine grain niobium cavities, and 1.3GHz low surface field copper cavity. The data will also include calculated RF frequency shift modeling non-uniform removal as a function of cavity position and comparing them with CBP results.

  11. Automated hippocampal subfield segmentation at 7 tesla MRI

    PubMed Central

    Wisse, Laura E.M.; Kuijf, Hugo J.; Honingh, Anita M.; Wang, Hongzhi; Pluta, John B.; Das, Sandhitsu R.; Wolk, David A.; Zwanenburg, Jaco J.M.; Yushkevich, Paul A.; Geerlings, Mirjam I.

    2015-01-01

    Purpose We aimed to evaluate an automated technique to segment hippocampal subfields and the entorhinal cortex (ERC) at 7 tesla MRI. Materials and Methods Cornu Ammonis (CA)1, CA2, CA3, dentate gyrus (DG), subiculum (SUB) and ERC were manually segmented, covering most of the long axis of the hippocampus, on 0.70 mm3 T2-weighted 7 tesla images of twenty-six participants (59±9 years, 46% men). The Automated Segmentation of Hippocampal Subfields (ASHS) approach was applied and evaluated using leave-one-out cross-validation. Results Comparison of automated segmentations with corresponding manual segmentation yielded a Dice similarity coefficient (DSC) of >0.75 for CA1, DG, SUB and ERC; and >0.54 for CA2 and CA3. Intraclass correlation coefficients (ICC) were >0.74 for CA1, DG and SUB; and >0.43 for CA2, CA3 and the ERC. Restricting the comparison of the ERC segmentation to a smaller range along the anterior-posterior axis improved both ICCs (left: 0.71; right: 0.82) and DSCs (left: 0.78; right: 0.77). The accuracy of ASHS vs a manual rater was lower, though only slightly for most subfields, than the intra-rater reliability of an expert manual rater, but was similar or slightly higher than the accuracy of an expert vs. a manual rater with ~170h of training for almost all subfields. Conclusion This work demonstrates the feasibility of using a computational technique to automatically label hippocampal subfields and the ERC at 7 tesla MRI, with a high accuracy for most subfields that is competitive with the labor intensive manual segmentation. The software and atlas are publicly available: http://www.nitrc.org/projects/ashs/. PMID:26846925

  12. Field quality measurements of a 2-Tesla transmission line magnet

    SciTech Connect

    Velev, G.V.; Foster, W.; Kashikhin, V.; Mazur, P.; Oleck, A.; Piekarz, H.; Schlabach, P.; Sylvester, C.; Wake, M.; /KEK, Tsukuba

    2005-09-01

    A prototype 2-Tesla superconducting transmission line magnet for future hadron colliders was designed, built and tested at Fermilab. The 1.5 m long, combined-function gradient-dipole magnet has a vertical pole aperture of 20 mm. To measure the magnetic field quality in such a small magnet aperture, a specialized rotating coil of 15.2 mm diameter, 0.69 m long was fabricated. Using this probe, a program of magnetic field quality measurements was successfully performed. Results of the measurements are presented and discussed.

  13. What's a Cavity?

    MedlinePlus

    ... cavity (say: KA-vuh-tee) develops when a tooth decays (say: dih-KAZE), or breaks down. A cavity ... and deeper over time. Cavities are also called dental caries (say: KARE-eez), and if you have a ...

  14. 77 FR 22383 - Petition for Exemption From the Federal Motor Vehicle Motor Theft Prevention Standard; TESLA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-13

    ... National Highway Traffic Safety Administration Petition for Exemption From the Federal Motor Vehicle Motor... full the petition of Tesla Motors Inc's. (Tesla) for an exemption of the Model S vehicle line in... is likely to be as effective in reducing and deterring motor vehicle theft as compliance with...

  15. Dark Current and X Ray Measurements of an 805 MHz Pillbox Cavity

    SciTech Connect

    J. Norem; P. Gruber; A. Bross; S. Geer; A. Moretti; Z Qian; D. M. Kaplan; Y. Torun; R. Rimmer; Derun Li; M. Zisman

    2003-05-01

    The muon cooling systems proposed for neutrino factories require low frequency (201 MHz) RF cavities with Be windows, at high gradient (Eacc {approx} 16 MV/m), in strong solenoidal magnetic field ({approx} 5 T). For the proposed Muon Ionization Cooling Experiment (MICE) [1], an experimental demonstration of cooling, we have an additional constraint that we must operate sensitive particle detectors very close to the RF cavities, which produce backgrounds from dark currents and x rays. To understand the processes involved in cavity conditioning and operation near particle detectors, we have constructed a test facility at Lab G of Fermilab, where a 5 Tesla superconducting solenoid, a 14 MW peak power klystron and a pillbox test cavity at 805 MHz are available. We present measurements of dark currents, x rays and surface structure from the pillbox cavity, with both copper and beryllium endplates, and discuss the interaction between surface structure and radiation backgrounds produced.

  16. Tuned cavity magnetometer sensitivity.

    SciTech Connect

    Okandan, Murat; Schwindt, Peter

    2009-09-01

    We have developed a high sensitivity (Tesla/{radical}Hz), non-cryogenic magnetometer that utilizes a novel optical (interferometric) detection technique. Further miniaturization and low-power operation are key advantages of this magnetometer, when compared to systems using SQUIDs which require liquid Helium temperatures and associated overhead to achieve similar sensitivity levels.

  17. 76 FR 60118 - Tesla Motors, Inc. Grant of Petition for Renewal of a Temporary Exemption From the Advanced Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-28

    ... National Highway Traffic Safety Administration Tesla Motors, Inc. Grant of Petition for Renewal of a... (FMVSS) No. 208, Occupant Crash Protection. SUMMARY: This notice grants the petition of Tesla Motors, Inc. (Tesla) for the renewal of a temporary exemption of its Roadster model from the advanced air...

  18. Hydrogen Degassing Study During the Heat Treatment of 1.3-GHZ SRF Cavities

    SciTech Connect

    Joung, Mijoung; Kim, H. J.; Rowe, A.; Wong, M.

    2013-10-02

    Superconducting radio frequency (SRF) cavities undergo a number of processes as part of its manufacturing procedure in order to optimize their performance. Among these processes is a high temperature hydrogen degas heat treatment used to prevent 'Q' decrease. The heat treatment occurs in the processing sequence after either chemically or mechanically polishing the cavity. This paper summarizes the hydrogen measurements during the heat treatment of a sample of chemically and mechanically polished single-cell and nine-cell 1.3-GHz cavities. The hydrogen measurements are analyzed according the polishing method, the polishing history, the amount of time that the cavity was baked at 800°C, and the temperature ramp rate.

  19. Dual frequency optical cavity

    DOEpatents

    George, E.V.; Schipper, J.F.

    Method and apparatus for generating two distinct laser frequencies in an optical cavity, using a T configuration laser cavity and means for intermittently increasing or decreasing the index of refraction n of an associated transmission medium in one arm of the optical cavity to enhance laser action in one arm or the second arm of the cavity.

  20. Dual frequency optical cavity

    DOEpatents

    George, E. Victor; Schipper, John F.

    1985-01-01

    Method and apparatus for generating two distinct laser frequencies in an optical cavity, using a "T" configuration laser cavity and means for intermittently increasing or decreasing the index of refraction n of an associated transmission medium in one arm of the optical cavity to enhance laser action in one arm or the second arm of the cavity.

  1. The NHMFL 60 tesla, 100 millisecond pulsed magnet

    SciTech Connect

    Boenig, H.J.; Campbell, L.J.; Rickel, D.G.; Rogers, J.D.; Schillig, J.B.; Sims, J.R.; Pernambuco-Wise, P.; Schneider-Muntau, H.J.

    1992-11-09

    Among the new facilities to be offered by the National Science Foundation through the National High Magnetic Field Laboratory (NHMFL) are pulsed fields that can only be achieved at a national user facility by virtue of their strength, duration, and volume. In particular, a 44 mm bore pulsed magnet giving a 60 tesla field for 100 ms is in the final design stage. This magnet will be powered by a 1.4 GW motor-generator at Los Alamos and is an important step toward proving design principles that will be needed for the higher field quasi-stationary pulsed magnets that this power source is capable of driving. This report will discuss specifications and parameters of this magnet.

  2. Report on the TESLA engineering study/review

    SciTech Connect

    C. Boffo et al.

    2002-07-18

    A team from Argonne National Lab, Cornell, Fermilab, Jefferson Lab, and SLAC has studied the TESLA TDR and its associated cost and manpower estimates, concentrating on the five largest cost sub-systems (Main Linac Modules, Main Linac RF Systems, Civil Engineering, Machine Infrastructure, and XFEL Incremental). These elements were concerned mainly with providing energy reach. We did not study the lower cost, but still technically challenging elements providing luminosity and physics capability, namely damping rings, beam delivery system, beam injection system, positron production, polarized beams, etc. The study did not attempt to validate the TDR cost estimates, but rather its purpose was to understand the technology and status of the large cost items, and the methodology by which their estimated cost was determined. In addition, topics of project oversight were studied.

  3. Sampling Hyperpolarized Molecules Utilizing a 1 Tesla Permanent Magnetic Field

    PubMed Central

    Tee, Sui Seng; DiGialleonardo, Valentina; Eskandari, Roozbeh; Jeong, Sangmoo; Granlund, Kristin L.; Miloushev, Vesselin; Poot, Alex J.; Truong, Steven; Alvarez, Julio A.; Aldeborgh, Hannah N.; Keshari, Kayvan R.

    2016-01-01

    Hyperpolarized magnetic resonance spectroscopy (HP MRS) using dynamic nuclear polarization (DNP) is a technique that has greatly enhanced the sensitivity of detecting 13C nuclei. However, the HP MRS polarization decays in the liquid state according to the spin-lattice relaxation time (T1) of the nucleus. Sampling of the signal also destroys polarization, resulting in a limited temporal ability to observe biologically interesting reactions. In this study, we demonstrate that sampling hyperpolarized signals using a permanent magnet at 1 Tesla (1T) is a simple and cost-effective method to increase T1s without sacrificing signal-to-noise. Biologically-relevant information may be obtained with a permanent magnet using enzyme solutions and in whole cells. Of significance, our findings indicate that changes in pyruvate metabolism can also be quantified in a xenograft model at this field strength. PMID:27597137

  4. Operating nanoliter scale NMR microcoils in a 1 tesla field

    NASA Astrophysics Data System (ADS)

    McDowell, Andrew F.; Adolphi, Natalie L.

    2007-09-01

    Microcoil probes enclosing sample volumes of 1.2, 3.3, 7.0, and 81 nanoliters are constructed as nuclear magnetic resonance (NMR) detectors for operation in a 1 tesla permanent magnet. The probes for the three smallest volumes utilize a novel auxiliary tuning inductor for which the design criteria are given. The signal-to-noise ratio (SNR) and line width of water samples are measured. Based on the measured DC resistance of the microcoils, together with the calculated radio frequency (RF) resistance of the tuning inductor, the SNR is calculated and shown to agree with the measured values. The details of the calculations indicate that the auxiliary inductor does not degrade the NMR probe performance. The diameter of the wire used to construct the microcoils is shown to affect the signal line widths.

  5. MRI at 7 Tesla and above: demonstrated and potential capabilities.

    PubMed

    Kraff, Oliver; Fischer, Anja; Nagel, Armin M; Mönninghoff, Christoph; Ladd, Mark E

    2015-01-01

    With more than 40 installed MR systems worldwide operating at 7 Tesla or higher, ultra-high-field (UHF) imaging has been established as a platform for clinically oriented research in recent years. Along with technical developments that, in part, have also been successfully transferred to lower field strengths, MR imaging and spectroscopy at UHF have demonstrated capabilities and potentials for clinical diagnostics in a variety of studies. In terms of applications, this overview article focuses on already achieved advantages for in vivo imaging, i.e., in imaging the brain and joints of the musculoskeletal system, but also considers developments in body imaging, which is particularly challenging. Furthermore, new applications for clinical diagnostics such as X-nuclei imaging and spectroscopy, which only really become feasible at ultra-high magnetic fields, will be presented.

  6. Sampling Hyperpolarized Molecules Utilizing a 1 Tesla Permanent Magnetic Field

    NASA Astrophysics Data System (ADS)

    Tee, Sui Seng; Digialleonardo, Valentina; Eskandari, Roozbeh; Jeong, Sangmoo; Granlund, Kristin L.; Miloushev, Vesselin; Poot, Alex J.; Truong, Steven; Alvarez, Julio A.; Aldeborgh, Hannah N.; Keshari, Kayvan R.

    2016-09-01

    Hyperpolarized magnetic resonance spectroscopy (HP MRS) using dynamic nuclear polarization (DNP) is a technique that has greatly enhanced the sensitivity of detecting 13C nuclei. However, the HP MRS polarization decays in the liquid state according to the spin-lattice relaxation time (T1) of the nucleus. Sampling of the signal also destroys polarization, resulting in a limited temporal ability to observe biologically interesting reactions. In this study, we demonstrate that sampling hyperpolarized signals using a permanent magnet at 1 Tesla (1T) is a simple and cost-effective method to increase T1s without sacrificing signal-to-noise. Biologically-relevant information may be obtained with a permanent magnet using enzyme solutions and in whole cells. Of significance, our findings indicate that changes in pyruvate metabolism can also be quantified in a xenograft model at this field strength.

  7. Design and prototype fabrication of a 30 tesla cryogenic magnet

    NASA Technical Reports Server (NTRS)

    Prok, G. M.; Swanson, M. C.; Brown, G. V.

    1977-01-01

    A liquid neon cooled magnet was designed to produce 30 teslas in steady operation. To ensure the correctness of the heat transfer relationships used, supercritical neon heat transfer tests were made. Other tests made before the final design included tests on the effect of the magnetic field on pump motors, tensile shear tests on the cryogenic adhesives, and simulated flow studies for the coolant. The magnet will consist of two pairs of coils, cooled by forced convection of supercritical neon. Heat from the supercritical neon will be rejected through heat exchangers which are made of roll bonded copper panels and are submerged in a pool of saturated liquid neon. A partial mock up coil was wound to identify the tooling required to wind the magnet. This was followed by winding a prototype pair of coils. The prototype winding established procedures for fabricating the final magnet and revealed slight changes needed in the final design.

  8. Comparison of the TESLA, NLC and CLIC beam collimation performance

    SciTech Connect

    Alexandr I Drozhdin et al.

    2003-03-27

    This note describes studies performed in the framework of the Collimation Task Force organized to support the work of the International Linear Collider Technical Review Committee. The post-linac beam-collimation systems in the TESLA, JLC/NLC and CLIC linear-collider designs are compared using the same computer code under the same assumptions. Their performance is quantified in terms of beam-halo and synchrotron-radiation collimation efficiency. The performance of the current designs varies across projects, and does not always meet the original design goals. But these comparisons suggest that achieving the required performance in a future linear collider is feasible. The post-TRC plans of the Collimation Task Force are briefly outlined in closing.

  9. Measurement of Microwave Parameters of a Superconducting Niobium Cavity

    NASA Astrophysics Data System (ADS)

    Azaryan, N. S.; Baturitskii, M. A.; Budagov, Yu. A.; Demin, D. L.; Dem‧yanov, S. E.; Karpovich, V. A.; Kniga, V. V.; Krivosheev, R. M.; Lyubetskii, N. V.; Maksimov, S. I.; Pobol‧, I. L.; Rodionova, V. N.; Shirkov, G. D.; Shumeiko, N. M.; Yurevich, S. V.

    2017-01-01

    This paper describes a method for direct measurement of the amplitude-frequency characteristics and the Q factor of empty superconducting niobium radio frequency Tesla-type cavities. An automated measuring complex that permits recording the superconductivity effect and measuring high Q values has been developed. Measurements have been made of the Q factors of the investigated objects (the first domestic 1.3-GHz niobium cavities) at a level no lower than 0.1·109 (with a maximum value of 1.2·1010) and a level of relative losses lower than 130 dB (with a minimum factor of 139.7 dB) at liquid nitrogen temperature.

  10. State of the art of multicell SC cavities and perspectives

    SciTech Connect

    Peter Kneisel

    2002-08-01

    Superconducting cavity technology has made major progresses in the last decade with the introduction of high purity niobium on an industrial scale and, at the same time, by an improved understanding of the limiting processes in cavity performance, such as multipacting, field emission loading and thermal break-down. Multicell niobium cavities for beta = 1 particle acceleration, e.g. for the TESLA project, are routinely exceeding gradients of Eacc = 20 MV/m after the application of surface preparation techniques such as buffered chemical polishing or electropolishing, high pressure ultrapure water rinsing, UHV heat treatment and clean room assembly. The successes of the technology for beta = 1 accelerators has triggered a whole set of possible future applications for beta < 1 particle acceleration such as spallation neutron sources (SNS, ESS), transmutation of nuclear waste (TRASCO, ASH) or rare isotopes (RIA). The most advanced of these projects is SNS now under construction at Oak Ridge National Laboratory. This paper will review the technical solutions adopted to advance SRF technology and their impact on cavity performance, based on the SNS prototyping efforts. 2K at these high gradients are no longer out of reach. For the accelerator builder the challenge remains to come up with a good and reasonable design, which takes into account the status of the technology and does not over-estimate the achievable cavity performances in a large assembly such as, e.g., a multi-cavity cryo-module. In the following the criteria for multi-cell sc cavity design are reviewed and it is attempted to give a snapshot of the present status of multi-cell cavity performances.

  11. Cryogenic Test of a Coaxial Coupling Scheme for Fundamental and Higher Order Modes in Superconducting Cavities

    SciTech Connect

    J.K. Sekutowicz, P. Kneisel

    2009-05-01

    A coaxial coupling device located in the beam pipe of the TESLA type superconducting cavities provides for better propagation of Higher Order Modes (HOMs) and their strong damping in appropriate HOM couplers. Additionally, it also provides efficient coupling for fundamental mode RF power into the superconducting cavity. The whole coupling device can be designed as a detachable system. If appropriately dimensioned, the magnetic field can be minimized to a negligible level at the flange position. This scheme, presented previously*, provides for several advantages: strong HOM damping, flangeable solution, exchangeability of the HOM damping device on a cavity, less complexity of the superconducting cavity, possible cost advantages. This contribution will describe the results of the first cryogenic test.

  12. OPTIMIZING CENTRIFUGAL BARREL POLISHING FOR MIRROR FINISH SRF CAVITY AND RF TESTS AT JEFFERSON LAB

    SciTech Connect

    Ari Palczewski, Rongli Geng, Hui Tian

    2012-07-01

    We performed Centrifugal Barrel Polishing (CBP) on a 1.3 GHz fine grain TESLA single cell cavity and 1.5 GHz fine grain CEBAF high gradient superconducting radio frequency (SRF) single cell cavity following a modified recipe originally developed at Fermi National Accelerator Lab (FNAL). We were able to obtain a mirror like surface similar to that obtained at FNAL, while reducing the number of CBP steps and total processing time. This paper will discuss the change in surface and subsequent cavity performance post CBP, after a 800 C bake (no pre-bake chemistry) and minimal controlled electro-polishing (10 micron). In addition to Q vs. E{sub ACC} thermometry mapping with preheating characteristics and optical inspection of the cavity after CBP will also be shown.

  13. High-Gradient Tests of the Single-Cell SC Cavity with a Feedback Waveguide

    SciTech Connect

    Yakovlev, V.; Solyak, N.; Wu, G.; Ge, M.; Gonin, I.; Khabiboulline, T.; Ozelis, J.; Rowe, A.; Avrakhov, P.; Kanareykin, A.; Rathke, J.

    2010-11-04

    Use of a superconducting (SC) traveling-wave accelerating (STWA) structure with a small phase advance per cell, rather than a standing-wave structure, may provide a significant increase in the accelerating gradient in the ILC linac [1]. For the same surface electric and magnetic fields, the STWA achieves an accelerating gradient 1.2 larger than TESLA-like standing-wave cavities. In addition, the STWA allows longer acceleration cavities, reducing the number of gaps between them. However, the STWA structure requires a SC feedback waveguide to return the few hundreds of MW of circulating RF power from the structure output to the structure input. A test single-cell cavity with feedback was designed and manufactured to demonstrate the possibility of proper processing to achieve a high accelerating gradient. The first results of high-gradient tests of a prototype 1.3 GHz single-cell cavity with feedback waveguide will be presented.

  14. Hydroforming of Multi-Cell Niobium and NbCu-Clad Cavities

    SciTech Connect

    X. Singer, I. Jelezov, A. Matheisen, W. Singer, P. Kneisel

    2009-05-01

    Technological aspects of seamless tube fabrication and multi-cell cavity production by hydroforming will be discussed. Problems related to the fabrication of seamless cavities from bulk niobium are mainly solved. Several two cell- and three cell- niobium cavities have been produced by hydroforming at DESY. A 9-cell cavity of the TESLA shape has been completed from three sub-sections at company ZANON. The cavity was treated by electropolishing (EP) and successfully RF-tested. Two 3-cell units equipped with niobium beam pipes are being RF-tested after BCP surface treatment. The temperature mapping method with Jlab’s two-cell thermometry system is applied for performance analysis. It is of particular interest to compare the seamless cavity quench locations to those from standard cavities. The cryogenic test results and the T-mapping findings will be discussed. Of special interest is the combination of the seamless technique with NbCu cladding, i.e. the fabrication of cavity from bimetallic clad NbCu tube by hydroforming. Fabrication of single-cell and multi-cell NbCu clad cavities by hydroforming from bimetallic tubes is proven. Some test results will be presented.

  15. Beamstrahlung Photon Load on the TESLA Extraction Septum Blade(LCC-0104)

    SciTech Connect

    Seryi, A

    2003-10-02

    This note describes work performed in the framework of the International Linear Collider Technical Review Committee [1] to estimate the power load on the TESLA extraction septum blade due to beamstrahlung photons. It is shown, that under realistic conditions the photon load can be several orders of magnitude higher than what was estimated in the TESLA TDR [2] for the ideal Gaussian beams, potentially representing a serious limitation of the current design.

  16. Dobutamine stress cardiovascular magnetic resonance at 3 Tesla

    PubMed Central

    Kelle, S; Hamdan, A; Schnackenburg, B; Köhler, U; Klein, C; Nagel, E; Fleck, E

    2008-01-01

    Purpose The assessment of inducible wall motion abnormalities during high-dose dobutamine-stress cardiovascular magnetic resonance (DCMR) is well established for the identification of myocardial ischemia at 1.5 Tesla. Its feasibility at higher field strengths has not been reported. The present study was performed to prospectively determine the feasibility and diagnostic accuracy of DCMR at 3 Tesla for depicting hemodynamically significant coronary artery stenosis (≥ 50% diameter stenosis) in patients with suspected or known coronary artery disease (CAD). Materials and methods Thirty consecutive patients (6 women) (66 ± 9.3 years) were scheduled for DCMR between January and May 2007 for detection of coronary artery disease. Patients were examined with a Philips Achieva 3 Tesla system (Philips Healthcare, Best, The Netherlands), using a spoiled gradient echo cine sequence. Technical parameters were: spatial resolution 2 × 2 × 8 mm3, 30 heart phases, spoiled gradient echo TR/TE: 4.5/2.6 msec, flip angle 15°. Images were acquired at rest and stress in accordance with a standardized high-dose dobutamine-atropine protocol during short breath-holds in three short and three long-axis views. Dobutamine was administered using a standard protocol (10 μg increments every 3 minutes up to 40 μg dobutamine/kg body weight/minute plus atropine if required to reach target heart rate). The study protocol included administration of 0.1 mmol/kg/body weight Gd-DTPA before the cine images at rest were acquired to improve the image quality. The examination was terminated if new or worsening wall-motion abnormalities or chest pain occurred or when > 85% of age-predicted maximum heart rate was reached. Myocardial ischemia was defined as new onset of wall-motion abnormality in at least one segment. In addition, late gadolinium enhancement (LGE) was performed. Images were evaluated by two blinded readers. Diagnostic accuracy was determined with coronary angiography as the reference

  17. Defect detection inside superconducting 1.3 GHz cavities by means of x-ray fluorescence spectroscopy

    SciTech Connect

    Bertucci, M.; Michelato, P.; Moretti, M.; Navitski, A.; Pagani, C.

    2016-01-15

    X-ray fluorescence probe for detection of foreign material inclusions on the inner surface of superconducting cavities has been developed and tested. The setup detects trace element content such as a few micrograms of impurities responsible for thermal breakdown phenomena limiting the cavity performance. The setup has been customized for the geometry of 1.3 GHz TESLA-type niobium cavities and focuses on the surface of equator area at around 103 mm from the centre axis of the cavities with around 20 mm detection spot. More precise localization of inclusions can be reconstructed by means of angular or lateral displacement of the cavity. Preliminary tests confirmed a very low detection limit for elements laying in the high efficiency spectrum zone (from 5 to 10 keV), and a high angular resolution allowing an accurate localization of defects within the equator surface.

  18. Design of a horizontal test cryostat for superconducting RF cavities for the FREIA facility at Uppsala University

    SciTech Connect

    Chevalier, N. R.; Thermeau, J.-P.; Bujard, P.; Junquera, T.; Hermansson, L.; Kern, R. Santiago; Ruber, R.

    2014-01-29

    Uppsala University is constructing a large scale facility, called FREIA (Facility for Research Instrumentation and Accelerator Development). FREIA includes a helium liquefier and an accelerator test facility and has the capacity to test superconducting radio-frequency (RF) cavities with the same RF system and RF power level as in an accelerator. A central element of FREIA is a horizontal test cryostat connected in closed loop to a helium liquefier. This cryostat can house two fully equipped (tuners, piezo, power coupler, helium tank) superconducting cavities to perform full RF high power tests and operate at temperatures between 1.8 K and 4.2 K. The cryostat is designed to accommodate a large array of superconducting cavities and magnets, among which the European Spallation Source (ESS) type spoke and high-β elliptical cavities as well as TESLA/ILC type elliptical cavities. The present status of the project and the design of the cryostat are reported.

  19. Cascading Tesla Oscillating Flow Diode for Stirling Engine Gas Bearings

    NASA Technical Reports Server (NTRS)

    Dyson, Rodger

    2012-01-01

    Replacing the mechanical check-valve in a Stirling engine with a micromachined, non-moving-part flow diode eliminates moving parts and reduces the risk of microparticle clogging. At very small scales, helium gas has sufficient mass momentum that it can act as a flow controller in a similar way as a transistor can redirect electrical signals with a smaller bias signal. The innovation here forces helium gas to flow in predominantly one direction by offering a clear, straight-path microchannel in one direction of flow, but then through a sophisticated geometry, the reversed flow is forced through a tortuous path. This redirection is achieved by using microfluid channel flow to force the much larger main flow into this tortuous path. While microdiodes have been developed in the past, this innovation cascades Tesla diodes to create a much higher pressure in the gas bearing supply plenum. In addition, the special shape of the leaves captures loose particles that would otherwise clog the microchannel of the gas bearing pads.

  20. A passively suspended Tesla pump left ventricular assist device.

    PubMed

    Izraelev, Valentin; Weiss, William J; Fritz, Bryan; Newswanger, Raymond K; Paterson, Eric G; Snyder, Alan; Medvitz, Richard B; Cysyk, Joshua; Pae, Walter E; Hicks, Dennis; Lukic, Branka; Rosenberg, Gerson

    2009-01-01

    The design and initial test results of a new passively suspended Tesla type left ventricular assist device blood pump are described. Computational fluid dynamics (CFD) analysis was used in the design of the pump. Overall size of the prototype device is 50 mm in diameter and 75 mm in length. The pump rotor has a density lower than that of blood and when spinning inside the stator in blood it creates a buoyant centering force that suspends the rotor in the radial direction. The axial magnetic force between the rotor and stator restrain the rotor in the axial direction. The pump is capable of pumping up to 10 L/min at a 70 mm Hg head rise at 8,000 revolutions per minute (RPM). The pump has demonstrated a normalized index of hemolysis level below 0.02 mg/dL for flows between 2 and 9.7 L/min. An inlet pressure sensor has also been incorporated into the inlet cannula wall and will be used for control purposes. One initial in vivo study showed an encouraging result. Further CFD modeling refinements are planned and endurance testing of the device.

  1. Design and prototype fabrication of a 30 tesla cryogenic magnet

    NASA Technical Reports Server (NTRS)

    Prok, G. M.; Swanson, M. C.; Brown, G. V.

    1977-01-01

    A liquid-neon-cooled magnet has been designed to produce 30 teslas in steady operation. Its feasibility was established by a previously reported parametric study. To ensure the correctness of the heat transfer relationships used, supercritical neon heat transfer tests were made. Other tests made before the final design included tests on the effect of the magnetic field on pump motors; tensile-shear tests on the cryogenic adhesives; and simulated flow studies for the coolant. The magnet will be made of two pairs of coils, cooled by forced convection of supercritical neon. Heat from the supercritical neon will be rejected through heat exchangers which are made of roll-bonded copper panels and are submerged in a pool of saturated liquid neon. A partial mock-up coil was wound to identify the tooling required to wind the magnet. This was followed by winding a prototype pair of coils. The prototype winding established procedures for fabricating the final magnet and revealed slight changes needed in the final design.

  2. A Passively-Suspended Tesla Pump Left Ventricular Assist Device

    PubMed Central

    Izraelev, Valentin; Weiss, William J.; Fritz, Bryan; Newswanger, Raymond K.; Paterson, Eric G.; Snyder, Alan; Medvitz, Richard B.; Cysyk, Joshua; Pae, Walter E.; Hicks, Dennis; Lukic, Branka; Rosenberg, Gerson

    2009-01-01

    The design and initial test results of a new passively suspended Tesla type LAVD blood pump are described. CFD analysis was used in the design of the pump. Overall size of the prototype device is 50 mm in diameter and 75 mm in length. The pump rotor has a density lower than that of blood and when spinning inside the stator in blood it creates a buoyant centering force that suspends the rotor in the radial direction. The axial magnetic force between the rotor and stator restrain the rotor in the axial direction. The pump is capable of pumping up to 10 liters/min at a 70 mmHg head rise at 8000 RPM. The pump has demonstrated a normalized index of hemolysis level below .02 mg/dL for flows between 2 and 9.7 L/min. An inlet pressure sensor has also been incorporated into the inlet cannula wall and will be used for control purposes. One initial in vivo study showed an encouraging result. Further CFD modeling refinements are planned as well as endurance testing of the device. PMID:19770799

  3. RESONANT CAVITY EXCITATION SYSTEM

    DOEpatents

    Baker, W.R.; Kerns, Q.A.; Riedel, J.

    1959-01-13

    An apparatus is presented for exciting a cavity resonator with a minimum of difficulty and, more specifically describes a sub-exciter and an amplifier type pre-exciter for the high-frequency cxcitation of large cavities. Instead of applying full voltage to the main oscillator, a sub-excitation voltage is initially used to establish a base level of oscillation in the cavity. A portion of the cavity encrgy is coupled to the input of the pre-exciter where it is amplified and fed back into the cavity when the pre-exciter is energized. After the voltage in the cavity resonator has reached maximum value under excitation by the pre-exciter, full voltage is applied to the oscillator and the pre-exciter is tunned off. The cavity is then excited to the maximum high voltage value of radio frequency by the oscillator.

  4. [Examination of upper abdominal region in high spatial resolution diffusion-weighted imaging using 3-Tesla MRI].

    PubMed

    Terada, Masaki; Matsushita, Hiroki; Oosugi, Masanori; Inoue, Kazuyasu; Yaegashi, Taku; Anma, Takeshi

    2009-03-20

    The advantage of the higher signal-to-noise ratio (SNR) of 3-Tesla magnetic resonance imaging (3-Tesla) has the possibility of contributing to the improvement of high spatial resolution without causing image deterioration. In this study, we compared SNR and the apparent diffusion coefficient (ADC) value with 3-Tesla as the condition in the diffusion-weighted image (DWI) parameter of the 1.5-Tesla magnetic resonance imaging (1.5-Tesla) and we examined the high spatial resolution images in the imaging method [respiratory-triggering (RT) method and breath free (BF) method] and artifact (motion and zebra) in the upper abdominal region of DWI at 3-Tesla. We have optimized scan parameters based on phantom and in vivo study. As a result, 3-Tesla was able to obtain about 1.5 times SNR in comparison with the 1.5-Tesla, ADC value had few differences. Moreover, the RT method was effective in correcting the influence of respiratory movement in comparison with the BF method, and image improvement by the effective acquisition of SNR and reduction of the artifact were provided. Thus, DWI of upper abdominal region was a useful sequence for the high spatial resolution in 3-Tesla.

  5. The pioneers of interplanetary communication: From Gauss to Tesla

    NASA Astrophysics Data System (ADS)

    Raulin-Cerceau, Florence

    2010-12-01

    The present overview covers the period from 1820 to the beginning of the 20th century. Emphasis is laid on the latter half of the 19th century because many efforts have been done at that time to elaborate schemes for contacting our neighboring planets by interplanetary telegraphy. This period knew many advances not only in planetary studies but also in the nascent field of telecommunications. Such a context led astronomers who were also interested in the problem of planetary habitability, to envisage that other planets could be contacted, especially the planet Mars. Interplanetary communication using a celestial telegraphy was planned during this period of great speculations about life on Mars. This paper focuses on four authors: the Frenchmen C. Flammarion, Ch. Cros, A. Mercier and the Serbian N. Tesla, who formulated early proposals to communicate with Mars or Venus. The first proposals (which remained only theoretical) showed that an initial reflection had started as early as the second part of the 19th century on the type of language that could be both universal and distinguishable from a natural signal. Literary history of interplanetary communication preceded by far the scientific one. Authors of the 1900s were very prolific on this topic. French fictions are mentioned in this paper as examples of such a literature. This incursion into selected texts stresses the fact that the problem of techniques and messages employed to communicate with other planets goes beyond the strict scientific framework. Finally, this paper aims to highlight the similarities as well as the differences between the different proposals and to underline what that could possibly help present SETI research to define messages supposed to be sent to other planetary systems.

  6. Synchronous optical transmission data link integrated with FPGA for TESLA FEL SIMCON system: long data vector optical transceiver module tests

    NASA Astrophysics Data System (ADS)

    Zielinski, Jerzy S.; Pozniak, Krzysztof T.; Romaniuk, Ryszard S.

    2006-10-01

    The X-ray free-electron laser X-FEL that is being planned at the DESY research center in cooperation with European partners will produce high-intensity ultra-short X-ray flashes with the properties of laser light. This new light source, which can only be described in terms of superlatives, will open up a whole range of new possibilities for the natural sciences. It could also offer very promising opportunities for industrial users. SIMCON (SIMulator and CONtroller) is the project of the fast, low latency digital controller dedicated to the LLRF system in VUV FEL experiment. The main purpose of the project is to create a controller to stabilize the vector sum of fields in cavities of one cryo-module in the experiment. The device can be also used as the simulator of the cavity and test bench for other devices. The synchronic, optical link project was made for the accelerator X-FEL laser TESLA, the LLRF control system experiment at DESY, Hamburg. The control and diagnostic data is transmitted up to 2.5Gbit/s through a plastic fiber in a distance up to a few hundred meters. The link is synchronized once after power up, and never resynchronized when data is transmitted with maximum speed. The one way link bit error rate is less then 10 -15. The transceiver component written in VHDL that works in the dedicated Altera® Stratix® GX FPGA circuit. During the work in the PERG laboratory a 2.5Gbit/s serial link with the long vector parallel interface transceiver was created. Long-Data-Vector transceiver transmits 16bit vector each 8ns with 120ns latency.

  7. Cavity enhanced terahertz modulation

    SciTech Connect

    Born, N.; Scheller, M.; Moloney, J. V.; Koch, M.

    2014-03-10

    We present a versatile concept for all optical terahertz (THz) amplitude modulators based on a Fabry-Pérot semiconductor cavity design. Employing the high reflectivity of two parallel meta-surfaces allows for trapping selected THz photons within the cavity and thus only a weak optical modulation of the semiconductor absorbance is required to significantly damp the field within the cavity. The optical switching yields to modulation depths of more than 90% with insertion efficiencies of 80%.

  8. A Laminar Flow-Based Microfluidic Tesla Pump via Lithography Enabled 3D Printing.

    PubMed

    Habhab, Mohammed-Baker; Ismail, Tania; Lo, Joe Fujiou

    2016-11-23

    Tesla turbine and its applications in power generation and fluid flow were demonstrated by Nicholas Tesla in 1913. However, its real-world implementations were limited by the difficulty to maintain laminar flow between rotor disks, transient efficiencies during rotor acceleration, and the lack of other applications that fully utilize the continuous flow outputs. All of the aforementioned limits of Tesla turbines can be addressed by scaling to the microfluidic flow regime. Demonstrated here is a microscale Tesla pump designed and fabricated using a Digital Light Processing (DLP) based 3D printer with 43 µm lateral and 30 µm thickness resolutions. The miniaturized pump is characterized by low Reynolds number of 1000 and a flow rate of up to 12.6 mL/min at 1200 rpm, unloaded. It is capable of driving a mixer network to generate microfluidic gradient. The continuous, laminar flow from Tesla turbines is well-suited to the needs of flow-sensitive microfluidics, where the integrated pump will enable numerous compact lab-on-a-chip applications.

  9. Diagnostic usefulness of 3 tesla MRI of the brain for cushing disease in a child.

    PubMed

    Ono, Erina; Ozawa, Ayako; Matoba, Kaori; Motoki, Takanori; Tajima, Asako; Miyata, Ichiro; Ito, Junko; Inoshita, Naoko; Yamada, Syozo; Ida, Hiroyuki

    2011-10-01

    It is sometimes difficult to confirm the location of a microadenoma in Cushing disease. Recently, we experienced an 11-yr-old female case of Cushing disease with hyperprolactinemia. She was referred to our hospital because of decrease of height velocity with body weight gain. On admission, she had typical symptoms of Cushing syndrome. Although no pituitary microadenomas were detected on 1.5 Tesla MRI of the brain, endocrinological examinations including IPS and CS sampling were consistent with Cushing disease with hyperprolactinemia. Oral administration of methyrapone instead of neurosurgery was started after discharge, but subsequent 3 Tesla MRI of the brain clearly demonstrated a 3-mm less-enhanced lesion in the left side of the pituitary gland. Finally, transsphenoidal surgery was performed, and a 3.5-mm left-sided microadenoma was resected. Compared with 1.5 Tesla MRI, 3 Tesla MRI offers the advantage of a higher signal to noise ratio (SNR), which provides higher resolution and proper image quality. Therefore, 3 Tesla MRI is a very useful tool to localize microadenomas in Cushing disease in children as well as in adults. It will be the first choice of radiological examinations in suspected cases of Cushing disease.

  10. A Laminar Flow-Based Microfluidic Tesla Pump via Lithography Enabled 3D Printing

    PubMed Central

    Habhab, Mohammed-Baker; Ismail, Tania; Lo, Joe Fujiou

    2016-01-01

    Tesla turbine and its applications in power generation and fluid flow were demonstrated by Nicholas Tesla in 1913. However, its real-world implementations were limited by the difficulty to maintain laminar flow between rotor disks, transient efficiencies during rotor acceleration, and the lack of other applications that fully utilize the continuous flow outputs. All of the aforementioned limits of Tesla turbines can be addressed by scaling to the microfluidic flow regime. Demonstrated here is a microscale Tesla pump designed and fabricated using a Digital Light Processing (DLP) based 3D printer with 43 µm lateral and 30 µm thickness resolutions. The miniaturized pump is characterized by low Reynolds number of 1000 and a flow rate of up to 12.6 mL/min at 1200 rpm, unloaded. It is capable of driving a mixer network to generate microfluidic gradient. The continuous, laminar flow from Tesla turbines is well-suited to the needs of flow-sensitive microfluidics, where the integrated pump will enable numerous compact lab-on-a-chip applications. PMID:27886051

  11. Optically measuring interior cavities

    SciTech Connect

    Stone, Gary Franklin

    2008-12-21

    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.

  12. A new approach to calculate the transport matrix in RF cavities

    SciTech Connect

    Eidelman, Yu.; Mokhov, N.; Nagaitsev, S.; Solyak, N.; /Fermilab

    2011-03-01

    A realistic approach to calculate the transport matrix in RF cavities is developed. It is based on joint solution of equations of longitudinal and transverse motion of a charged particle in an electromagnetic field of the linac. This field is a given by distribution (measured or calculated) of the component of the longitudinal electric field on the axis of the linac. New approach is compared with other matrix methods to solve the same problem. The comparison with code ASTRA has been carried out. Complete agreement for tracking results for a TESLA-type cavity is achieved. A corresponding algorithm will be implemented into the MARS15 code. A realistic approach to calculate the transport matrix in RF cavities is developed. Complete agreement for tracking results with existed code ASTRA is achieved. New algorithm will be implemented into MARS15 code.

  13. Development of Large Grain/Single Crystal Niobium Cavity Technology at Jefferson Lab

    NASA Astrophysics Data System (ADS)

    Kneisel, P.; Myneni, G. R.; Ciovati, G.; Sekutowicz, J.; Carneiro, T.

    2007-08-01

    Approximately two years ago we started to develop high performance niobium accelerating cavities based on large grain or single crystal high purity niobium. We have fabricated and tested 15 single cell cavities of various shapes and frequencies between 1300 MHz and 2300 MHz using material from a total of 9 different very large grain niobium ingots from four niobium suppliers. The materials differed not only in grain sizes, but also in RRR — value and in the amount of Ta contained in the material. In one ingot supplied by CBMM the central grain exceeded 7 inches in diameter and this was used to fabricate two 2.2 GHz cavities. A single crystal 1300 MHz mono-cell cavity was also produced at DESY by rolling out a single crystal to the size required for this cavity. It was sent to Jlab for surface treatment and testing. In addition, we have fabricated three 7-cell cavities: two of the Jlab high gradient (HG) shape and one of the ILC Low Loss shape. Two 9-cell TESLA shape cavities are presently in fabrication at Jlab and are close to completion.

  14. Development of Large Grain/Single Crystal Niobium Cavity Technology at Jefferson Lab

    SciTech Connect

    Kneisel, P.; Myneni, G. R.; Ciovati, G.; Sekutowicz, J.; Carneiro, T.

    2007-08-09

    Approximately two years ago we started to develop high performance niobium accelerating cavities based on large grain or single crystal high purity niobium. We have fabricated and tested 15 single cell cavities of various shapes and frequencies between 1300 MHz and 2300 MHz using material from a total of 9 different very large grain niobium ingots from four niobium suppliers. The materials differed not only in grain sizes, but also in RRR - value and in the amount of Ta contained in the material. In one ingot supplied by CBMM the central grain exceeded 7 inches in diameter and this was used to fabricate two 2.2 GHz cavities. A single crystal 1300 MHz mono-cell cavity was also produced at DESY by rolling out a single crystal to the size required for this cavity. It was sent to Jlab for surface treatment and testing. In addition, we have fabricated three 7-cell cavities: two of the Jlab high gradient (HG) shape and one of the ILC Low Loss shape. Two 9-cell TESLA shape cavities are presently in fabrication at Jlab and are close to completion.

  15. Development of large Grain/Single Crystal Niobium Cavity Technology at Jefferson Lab

    SciTech Connect

    Peter Kneisel; J. Sekutowicz; T. Carneiro; G. Ciovati

    2006-10-31

    Approximately two years ago we started to develop high performance niobium accelerating cavities based on large grain or single crystal high purity niobium. We have fabricated and tested 15 single cell cavities of various shapes and frequencies between 1300 MHz and 2300 MHz using material from a total of 9 different very large grain niobium ingots from four niobium suppliers. The materials differed not only in grain sizes, but also in RRR ? value and in the amount of Ta contained in the material. In one ingot supplied by CBMM the central grain exceeded 7 inches in diameter and this was used to fabricate two 2.2 GHz cavities. A single crystal 1300 MHz mono-cell cavity was also produced at DESY by rolling out a single crystal to the size required for this cavity. It was sent to Jlab for surface treatment and testing. In addition, we have fabricated three 7-cell cavities: two of the Jlab high gradient (HG) shape and one of the ILC Low Loss shape. Two 9-cell TESLA shape cavities are presently in fabrication at Jlab and are close to completion.

  16. Progress on a Cavity with Beryllium Walls for Muon Ionization Cooling Channel R&D.

    SciTech Connect

    Bowring, D. L.; DeMello, A. J.; Lambert, A. R.; Li, D.; Virostek, S.; Zisman, M.; Kaplan, D.; Palmer, R. B.

    2012-05-20

    The Muon Accelerator Program (MAP) collaboration is working to develop an ionization cooling channel for muon beams. An ionization cooling channel requires the operation of high-gradient, normal-conducting RF cavities in multi-Tesla solenoidal magnetic fields. However, experiments conducted at Fermilab?s MuCool Test Area (MTA) show that increasing the solenoidal field strength reduces the maximum achievable cavity gradient. This gradient limit is characterized by an RF breakdown process that has caused significant damage to copper cavity interiors. The damage may be caused by field-emitted electrons, focused by the solenoidal magnetic field onto small areas of the inner cavity surface. Local heating may then induce material fatigue and surface damage. Fabricating a cavity with beryllium walls would mitigate this damage due to beryllium?s low density, low thermal expansion, and high electrical and thermal conductivity. We address the design and fabrication of a pillbox RF cavity with beryllium walls, in order to evaluate the performance of high-gradient cavities in strong magnetic fields.

  17. Note: Tesla based pulse generator for electrical breakdown study of liquid dielectrics

    NASA Astrophysics Data System (ADS)

    Veda Prakash, G.; Kumar, R.; Patel, J.; Saurabh, K.; Shyam, A.

    2013-12-01

    In the process of studying charge holding capability and delay time for breakdown in liquids under nanosecond (ns) time scales, a Tesla based pulse generator has been developed. Pulse generator is a combination of Tesla transformer, pulse forming line, a fast closing switch, and test chamber. Use of Tesla transformer over conventional Marx generators makes the pulse generator very compact, cost effective, and requires less maintenance. The system has been designed and developed to deliver maximum output voltage of 300 kV and rise time of the order of tens of nanoseconds. The paper deals with the system design parameters, breakdown test procedure, and various experimental results. To validate the pulse generator performance, experimental results have been compared with PSPICE simulation software and are in good agreement with simulation results.

  18. Liquid neon heat transfer as applied to a 30 tesla cryomagnet

    NASA Technical Reports Server (NTRS)

    Papell, S. S.; Hendricks, R. C.

    1975-01-01

    Since superconducting magnets cooled by liquid helium are limited to magnetic fields of about 18 teslas, the design of a 30 tesla cryomagnet necessitates forced convection liquid neon heat transfer in small coolant channels. As these channels are too small to handle the vapor flow if the coolant were to boil, the design philosophy calls for suppressing boiling by subjecting the fluid to high pressures. Forced convection heat transfer data are obtained by using a blowdown technique to force the fluid vertically through a resistance-heated instrumented tube. The data are obtained at inlet temperatures between 28 and 34 K and system pressures between 28 to 29 bars. Data correlation is limited to a very narrow range of test conditions, since the tests were designed to simulate the heat transfer characteristics in the coolant channels of the 30 tesla cryomagnet concerned. The results can therefore be applied directly to the design of the magnet system.-

  19. Nikola Tesla: Why was he so much resisted and forgotten? [Retrospectroscope].

    PubMed

    Valentinuzzi, Max E; Ortiz, Martin Hill; Cervantes, Daniel; Leder, Ron S

    2016-01-01

    Recently, during the Christmas season, a friend of mine visited me and, sneaking a look at my bookshelves, found two rather old Nikola Tesla biographies, which I had used to prepare a "Retrospectroscope" column for the then-named IEEE Engineering in Medicine and Biology Magazine when our dear friend Alvin Wald was its editor-inchief [2]. Eighteen years have elapsed since then; soon, the idea came up of revamping the article. Cynthia Weber, the magazine's current associate editor, considered it acceptable, and here is the new note divided in two parts: that is, a slightly revised version of the original article followed by new material, including some quite interesting information regarding Tesla's homes and laboratories. On top of this, Tesla is not devoid of a science fiction touch, as mentioned at the end.

  20. What's a Cavity?

    MedlinePlus

    ... and deeper over time. Cavities are also called dental caries (say: KARE-eez), and if you have a cavity, it's important to get it repaired. But why would your ... and when plaque clings to your teeth, the acids can eat away at the outermost ...

  1. CAVITY EXCITATION CIRCUIT

    DOEpatents

    Franck, J.V.

    1959-10-20

    An electronic oscillator is described for energizing a resonant cavity and to a system for stabilizing the operatin g frequency of the oscillator at the particular frequency necessary to establish a particular preferred field configuration or mode in the cavity, in this instance a linear accelerator. A freely rnnning oscillator has an output coupled to a resonant cavity wherein a field may be built up at any one of several adjacent frequencies. A pickup loop in the cavity is suitably shielded and positioned in the cavity so that only energy at the panticular desired frequency is fed back to stabilize the oscillator. A phase and gain control is in cluded in the feedback line.

  2. Passivated niobium cavities

    DOEpatents

    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. Magnetic Semiconductor Quantum Wells in High Fields to 60 Tesla: Photoluminescence Linewidth Annealing at Magnetization Steps

    SciTech Connect

    Awschalom, D.D.; Crooker, S.A.; Lyo, S.K.; Rickel, D.G.; Samarth, N.

    1999-05-24

    Magnetic semiconductors offer a unique possibility for strongly tuning the intrinsic alloy disorder potential with applied magnetic field. We report the direct observation of a series of step-like reductions in the magnetic alloy disorder potential in single ZnSe/Zn(Cd,Mn)Se quantum wells between O and 60 Tesla. This disorder, measured through the linewidth of low temperature photoluminescence spectra drops abruptly at -19, 36, and 53 Tesla, in concert with observed magnetization steps. Conventional models of alloy disorder (developed for nonmagnetic semiconductors) reproduce the general shape of the data, but markedly underestimate the size of the linewidth reduction.

  4. 3.0 Tesla vs 1.5 Tesla breast magnetic resonance imaging in newly diagnosed breast cancer patients

    PubMed Central

    Butler, Reni S; Chen, Christine; Vashi, Reena; Hooley, Regina J; Philpotts, Liane E

    2013-01-01

    AIM: To compare 3.0 Tesla (T) vs 1.5T magnetic resonance (MR) imaging systems in newly diagnosed breast cancer patients. METHODS: Upon Institutional Review Board approval, a Health Insurance Portability and Accountability Act-compliant retrospective review of 147 consecutive 3.0T MR examinations and 98 consecutive 1.5T MR examinations in patients with newly diagnosed breast cancer between 7/2009 and 5/2010 was performed. Eleven patients who underwent neoadjuvant chemotherapy in the 3.0T group were excluded. Mammographically occult suspicious lesions (BIRADS Code 4 and 5) additional to the index cancer in the ipsilateral and contralateral breast were identified. Lesion characteristics and pathologic diagnoses were recorded, and results achieved with both systems compared. Statistical significance was analyzed using Fisher’s exact test. RESULTS: In the 3.0T group, 206 suspicious lesions were identified in 55% (75/136) of patients and 96% (198/206) of these lesions were biopsied. In the 1.5T group, 98 suspicious lesions were identified in 53% (52/98) of patients and 90% (88/98) of these lesions were biopsied. Biopsy results yielded additional malignancies in 24% of patients in the 3.0T group vs 14% of patients in the 1.5T group (33/136 vs 14/98, P = 0.07). Average size and histology of the additional cancers was comparable. Of patients who had a suspicious MR imaging study, additional cancers were found in 44% of patients in the 3.0T group vs 27% in the 1.5T group (33/75 vs 14/52, P = 0.06), yielding a higher positive predictive value (PPV) for biopsies performed with the 3.0T system. CONCLUSION: 3.0T MR imaging detected more additional malignancies in patients with newly diagnosed breast cancer and yielded a higher PPV for biopsies performed with the 3.0T system. PMID:24003354

  5. Tuned optical cavity magnetometer

    DOEpatents

    Okandan, Murat; Schwindt, Peter

    2010-11-02

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

  6. [3 Tesla MRI: successful results with higher field strengths].

    PubMed

    Schmitt, F; Grosu, D; Mohr, C; Purdy, D; Salem, K; Scott, K T; Stoeckel, B

    2004-01-01

    The recent development of 3 Tesla MRI (3T MRI) has been fueled by promise of increased signal-to-noise ratio(SNR). Many are excited about the opportunity to not only use the increased SNR for clearer images, but also the chance to exchange it for better resolution or faster scans. These possibilities have caused a rapid increase in the market for 3T MRI, where the faster scanning tips an already advantageous economic outlook in favor of the user. As a result, the global market for 3T has grown from a research only market just a few years ago to an ever-increasing clinically oriented customer base. There are, however, significant obstacles to 3T MRI presented by the physics at higher field strengths. For example, the T1 relaxation times are prolonged with increasing magnet field strength. Further, the increased RF-energy deposition (SAR), the larger the chemical shift and the stronger susceptibility effect have to be considered as challenges. It is critical that one looks at both the advantages and disadvantages of using 3T. While there are many issues to address aand a number of different methods for doing so, to properly tackle each of these concerns will take time and effort on the part od researchers and clinicians. The optimization of 3T MRI scanning will have to be a combined effort, though much of the work to date has been in neuroimaging. Multiple applications have been explored in addition to clinical anatomical imaging, where resolution is improved showing structure in the brain never seen before in human MRI. Body and cardiac imaging provide a great challenge but are also achievable at 3T. As an example, the full range of clinical applications currently achieved on today's state-of-the-art 1.5T cardiac MR scanners has also been demonstrated at 3T. In the body, the full range of contrast is available over large fields of view allowing whole liver studies in the clinic or, as needed, one may choose a smaller field of view for high-resolution imaging of the

  7. Shot noise startup of the 6 nm SASE FEL at the TESLA test facility

    NASA Astrophysics Data System (ADS)

    Pierini, P.; Fawley, W. M.

    1996-02-01

    We present here the results of an extensive simulation activity for the TESLA SASE FEL. We have used the program GINGER to determine the FEL saturation length and the power fluctuations from shot to shot. The spectral properties of the output power and the correlation functions are investigated and compared with available theoretical models.

  8. Prospects for 6 to 10 tesla magnets for a TEVATRON upgrade

    SciTech Connect

    Mantsch, Paul M.

    1988-07-08

    The first SSC physics is at least 10 years away. An upgrade of the Fermilab Tevatron will ensure the continuity of a vigorous high-energy physics program until the SSC turns on. Three basic proposals are under consideration: /bar p/p at 3 /times/ 10/sup 31/ --Increase luminosity by improvements to the p source. pp at 1 TeV and 2 /times/ 10/sup 32/--Move the main ring to a new tunnel, build a second Tevatron ring, and /bar p/p > 1.5 TeV and 7 /times/ 10/sup 30/--Replace the tevatron with a higher energy ring. The last two options requires about a hundred 6.6-tesla dipoles in addition to a ring of Tevatron strength (4.4 T) magnets. These higher-field magnets are necessary in both rings to lengthen the straight sections in order to realize the collision optics. The third option requires a ring of magnets of 6.6 T or slightly higher to replace the present Tevatron plus a number of special 8--9 tesla magnets. The viability of the high-energy option then depends on the practicality of sizable numbers of reliable 8--9 tesla dipoles as well as 800 6.6-tesla dipoles. The following develops a specification for an 8.8 T dipole, examines the design considerations and reviews the current state of high-field magnet development. 22 figs., 3 tabs.

  9. 76 FR 47639 - Tesla Motors, Inc.; Receipt of Petition for Temporary Exemption From the Electronic Stability...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-05

    ... determine how best to optimize its battery design and vehicle software for future vehicle offerings such as... database of information for its future vehicle offerings. Tesla states that it cannot replicate this data... long range, highway-capable, battery-powered electric vehicle in the United States will lead to...

  10. Design study of 15-Tesla RHQT Nb3Al block type dipole magnet

    SciTech Connect

    Yamada, R.; Ambrosio, G.; Barzi, E.; Kashikin, V.; Kikuchi, A.; Novitski, I.; Takeuchi, T.; Wake, M.; Zlobin, A.; /Fermilab /NIMC, Tsukuba /KEK, Tsukuba

    2005-09-01

    The design study of the block type 15-Tesla RHQT Nb{sub 3}Al dipole magnet, and its merits over Nb{sub 3}Sn magnets are presented. The copper stabilized RHQT Nb{sub 3}Al strand is now becoming commercially available for the application to the accelerator magnets. A 1 mm diameter RHQT Nb{sub 3}Al strand with filament size about 50 {mu}, non-copper Jc about 1000 A/mm{sup 2} at 15 Tesla at 4.2K, copper ratio of 50%, can now be produced over several hundred meters. The stress and strain characteristics of the Nb{sub 3}Al strand are superior to the Nb{sub 3}Sn strand. Another advantage is that it can tolerate a longitudinal strain up to 0.55%. The RHQT Nb{sub 3}Al Rutherford cable will have less chance of contamination of the stabilizer, compared to Nb{sub 3}Sn cable. These characteristics of the RHQT Nb{sub 3}Al will be beneficial for designing and producing 15-Tesla dipole magnets. An example 15-Tesla magnet cross section, utilizing the RHQT Nb{sub 3}Sn strand is presented. A systematic investigation on RHQT Nb{sub 3}Al strands, its Rutherford cables, and building a small racetrack magnet for cable testing are proposed.

  11. Encouraging a "Romantic Understanding" of Science: The Effect of the Nikola Tesla Story

    ERIC Educational Resources Information Center

    Hadzigeorgiou, Yannis; Klassen, Stephen; Klassen, Cathrine Froese

    2012-01-01

    The purpose of this paper is to discuss and apply the notion of romantic understanding by outlining its features and its potential role in science education, to identify its features in the story of Nikola Tesla, and to describe an empirical study conducted to determine the effect of telling such a story to Grade 9 students. Elaborated features of…

  12. INVESTIGATION OF BREAKDOWN INDUCED SURFACE DAMAGE ON 805 MHZ PILLBOX CAVITY INTERIOR SURFACES

    SciTech Connect

    Jana, M. R.; Chung, M.; Leonova, M.; Moretti, A.; Tollestrup, A.; Yonehara, K.; Freemire, B.; Torun, Y.; Bowring, D.; Flanagan, G.

    2013-09-25

    The MuCool Test Area (MTA) at Fermilab is a facility to develop the technology required for ionization cooling for a future Muon Collider and/or Neutrino Factory. As part of this research program, we have tested two 805 MHz vacuum RF cavities in a multi-Tesla magnetic field to study the effects of the static magnetic field on the cavity operation. This study gives useful information on field emitters in the cavity, dark current, surface conditioning, breakdown mechanisms and material properties of the cavity. All these factors determine the maximum accelerating gradient in the cavity. This paper discusses the image processing technique for quantitative estimation of spark damage spot distribution on cavity interior surfaces. The distribution is compared with the electric field distribution predicted by a computer code calculation. The local spark density is proportional to probability of surface breakdown and shows a power law dependence on the maximum electric field (E). This E dependence is consistent with the dark current calculated from the Fowler-Nordheim equation.

  13. CIRCULAR CAVITY SLOT ANTENNA

    DOEpatents

    Kerley, P.L.

    1959-01-01

    A small-size antenna having a doughnut-shaped field pattern and which can act both as an antenna and a resonant circuit is described. The antenna is of the slotted type and comprises a resonant cavity with a center hole. A circular slot is provided in one wall of the cavity concentric with the hole and a radio frequency source is connected across the slot. The pattern and loading of the antenna are adjusted by varying the position and shape of a center element slidably disposed within the hole and projecting from the slotted side of the resonant cavity. The disclosed structure may also be used to propagate the oscillator signal down a transniission line by replacing the center element with one leg of the transmission line in a spaced relation from the walls of the cavity.

  14. Ring resonant cavities for spectroscopy

    DOEpatents

    Zare, R.N.; Martin, J.; Paldus, B.A.; Xie, J.

    1999-06-15

    Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS). 6 figs.

  15. Ring resonant cavities for spectroscopy

    DOEpatents

    Zare, Richard N.; Martin, Juergen; Paldus, Barbara A.; Xie, Jinchun

    1999-01-01

    Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS).

  16. Coupled resonator vertical cavity laser

    SciTech Connect

    Choquette, K.D.; Chow, W.W.; Hou, H.Q.; Geib, K.M.; Hammons, B.E.

    1998-01-01

    The monolithic integration of coupled resonators within a vertical cavity laser opens up new possibilities due to the unique ability to tailor the interaction between the cavities. The authors report the first electrically injected coupled resonator vertical-cavity laser diode and demonstrate novel characteristics arising from the cavity coupling, including methods for external modulation of the laser. A coupled mode theory is used model the output modulation of the coupled resonator vertical cavity laser.

  17. Metasurface external cavity laser

    SciTech Connect

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

    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.

  18. Video Toroid Cavity Imager

    DOEpatents

    Gerald, II, Rex E.; Sanchez, Jairo; Rathke, Jerome W.

    2004-08-10

    A video toroid cavity imager for in situ measurement of electrochemical properties of an electrolytic material sample includes a cylindrical toroid cavity resonator containing the sample and employs NMR and video imaging for providing high-resolution spectral and visual information of molecular characteristics of the sample on a real-time basis. A large magnetic field is applied to the sample under controlled temperature and pressure conditions to simultaneously provide NMR spectroscopy and video imaging capabilities for investigating electrochemical transformations of materials or the evolution of long-range molecular aggregation during cooling of hydrocarbon melts. The video toroid cavity imager includes a miniature commercial video camera with an adjustable lens, a modified compression coin cell imager with a fiat circular principal detector element, and a sample mounted on a transparent circular glass disk, and provides NMR information as well as a video image of a sample, such as a polymer film, with micrometer resolution.

  19. Effect of non-uniform surface resistance on the quality factor of superconducting niobium cavity

    NASA Astrophysics Data System (ADS)

    Tan, Weiwei; Lu, Xiangyang; Yang, Ziqin; Zhao, Jifei; Yang, Deyu; Yang, Yujia

    2016-08-01

    The formula Rs = G /Q0 is commonly used in the calculation of the surface resistance of radio frequency niobium superconducting cavities. The applying of such equation is under the assumption that surface resistance is consistent over the cavity. However, the distribution of the magnetic field varies over the cavity. The magnetic field in the equator is much higher than that in the iris. According to Thermal Feedback Theory, it leads non-uniform distribution of the density of heat flux, which results in a different temperature distribution along the cavity inter surface. The BCS surface resistance, which depends largely on the temperature, is different in each local inner surface. In this paper, the effect of surface non-uniform resistance on the quality factor has been studied, through the calculation of Q0 in the original definition of it. The results show that it is necessary to consider the non-uniform distribution of magnetic field when the accelerating field is above 20 MV/m for TESLA cavities. Also, the effect of inhomogeneity of residual resistance on the quality factor is discussed. Its distribution barely affects the quality factor.

  20. Application of extremum seeking for time-varying systems to resonance control of RF cavities

    SciTech Connect

    Scheinker, Alexander

    2016-09-13

    A recently developed form of extremum seeking for time-varying systems is implemented in hardware for the resonance control of radio-frequency cavities without phase measurements. Normal conducting RF cavity resonance control is performed via a slug tuner, while superconducting TESLA-type cavity resonance control is performed via piezo actuators. The controller maintains resonance by minimizing reflected power by utilizing model-independent adaptive feedback. Unlike standard phase-measurement-based resonance control, the presented approach is not sensitive to arbitrary phase shifts of the RF signals due to temperature-dependent cable length or phasemeasurement hardware changes. The phase independence of this method removes common slowly varying drifts and required periodic recalibration of phase-based methods. A general overview of the adaptive controller is presented along with the proof of principle experimental results at room temperature. Lastly, this method allows us to both maintain a cavity at a desired resonance frequency and also to dynamically modify its resonance frequency to track the unknown time-varying frequency of an RF source, thereby maintaining maximal cavity field strength, based only on power-level measurements.

  1. Application of extremum seeking for time-varying systems to resonance control of RF cavities

    DOE PAGES

    Scheinker, Alexander

    2016-09-13

    A recently developed form of extremum seeking for time-varying systems is implemented in hardware for the resonance control of radio-frequency cavities without phase measurements. Normal conducting RF cavity resonance control is performed via a slug tuner, while superconducting TESLA-type cavity resonance control is performed via piezo actuators. The controller maintains resonance by minimizing reflected power by utilizing model-independent adaptive feedback. Unlike standard phase-measurement-based resonance control, the presented approach is not sensitive to arbitrary phase shifts of the RF signals due to temperature-dependent cable length or phasemeasurement hardware changes. The phase independence of this method removes common slowly varying drifts andmore » required periodic recalibration of phase-based methods. A general overview of the adaptive controller is presented along with the proof of principle experimental results at room temperature. Lastly, this method allows us to both maintain a cavity at a desired resonance frequency and also to dynamically modify its resonance frequency to track the unknown time-varying frequency of an RF source, thereby maintaining maximal cavity field strength, based only on power-level measurements.« less

  2. A technique for monitoring fast tuner piezoactuator preload forces for superconducting rf cavities

    SciTech Connect

    Pischalnikov, Y.; Branlard, J.; Carcagno, R.; Chase, B.; Edwards, H.; Orris, D.; Makulski, A.; McGee, M.; Nehring, R.; Poloubotko, V.; Sylvester, C.; /Fermilab

    2007-06-01

    The technology for mechanically compensating Lorentz Force detuning in superconducting RF cavities has already been developed at DESY. One technique is based on commercial piezoelectric actuators and was successfully demonstrated on TESLA cavities [1]. Piezo actuators for fast tuners can operate in a frequency range up to several kHz; however, it is very important to maintain a constant static force (preload) on the piezo actuator in the range of 10 to 50% of its specified blocking force. Determining the preload force during cool-down, warm-up, or re-tuning of the cavity is difficult without instrumentation, and exceeding the specified range can permanently damage the piezo stack. A technique based on strain gauge technology for superconducting magnets has been applied to fast tuners for monitoring the preload on the piezoelectric assembly. The design and testing of piezo actuator preload sensor technology is discussed. Results from measurements of preload sensors installed on the tuner of the Capture Cavity II (CCII)[2] tested at FNAL are presented. These results include measurements during cool-down, warmup, and cavity tuning along with dynamic Lorentz force compensation.

  3. Design study of steady-state 30-tesla liquid-neon-cooled magnet

    NASA Technical Reports Server (NTRS)

    Prok, G. M.; Brown, G. V.

    1976-01-01

    A design for a 30-tesla, liquid-neon-cooled magnet was reported which is capable of continuous operation. Cooled by nonboiling, forced-convection heat transfer to liquid neon flowing at 2.8 cu m/min in a closed, pressurized heat-transfer loop and structurally supported by a tapered structural ribbon, the tape-wound coils with a high-purity-aluminum conductor will produce over 30 teslas for 1 minute at 850 kilowatts. The magnet will have an inside diameter of 7.5 centimeters and an outside diameter of 54 centimeters. The minimum current density at design field will be 15.7 kA/sq cm.

  4. Rapid Parametric Mapping of the Longitudinal Relaxation Time T1 Using Two-Dimensional Variable Flip Angle Magnetic Resonance Imaging at 1.5 Tesla, 3 Tesla, and 7 Tesla

    PubMed Central

    Dieringer, Matthias A.; Deimling, Michael; Santoro, Davide; Wuerfel, Jens; Madai, Vince I.; Sobesky, Jan; von Knobelsdorff-Brenkenhoff, Florian; Schulz-Menger, Jeanette; Niendorf, Thoralf

    2014-01-01

    Introduction Visual but subjective reading of longitudinal relaxation time (T1) weighted magnetic resonance images is commonly used for the detection of brain pathologies. For this non-quantitative measure, diagnostic quality depends on hardware configuration, imaging parameters, radio frequency transmission field (B1+) uniformity, as well as observer experience. Parametric quantification of the tissue T1 relaxation parameter offsets the propensity for these effects, but is typically time consuming. For this reason, this study examines the feasibility of rapid 2D T1 quantification using a variable flip angles (VFA) approach at magnetic field strengths of 1.5 Tesla, 3 Tesla, and 7 Tesla. These efforts include validation in phantom experiments and application for brain T1 mapping. Methods T1 quantification included simulations of the Bloch equations to correct for slice profile imperfections, and a correction for B1+. Fast gradient echo acquisitions were conducted using three adjusted flip angles for the proposed T1 quantification approach that was benchmarked against slice profile uncorrected 2D VFA and an inversion-recovery spin-echo based reference method. Brain T1 mapping was performed in six healthy subjects, one multiple sclerosis patient, and one stroke patient. Results Phantom experiments showed a mean T1 estimation error of (-63±1.5)% for slice profile uncorrected 2D VFA and (0.2±1.4)% for the proposed approach compared to the reference method. Scan time for single slice T1 mapping including B1+ mapping could be reduced to 5 seconds using an in-plane resolution of (2×2) mm2, which equals a scan time reduction of more than 99% compared to the reference method. Conclusion Our results demonstrate that rapid 2D T1 quantification using a variable flip angle approach is feasible at 1.5T/3T/7T. It represents a valuable alternative for rapid T1 mapping due to the gain in speed versus conventional approaches. This progress may serve to enhance the capabilities of

  5. Programmable infusion pump and catheter: evaluation using 3-tesla magnetic resonance imaging.

    PubMed

    Shellock, Frank G; Crivelli, Rocco; Venugopalan, Ramakrishna

    2008-07-01

    Objective.  This study assessed 3-Tesla magnetic resonance imaging (MRI) issues for a programmable infusion pump and associated catheters. Methods.  A programmable infusion pump and associated catheters (MedStream Programmable Infusion Pump, 40 mL; SureStream TI Coil-Reinforced Intraspinal Catheter; SureStream TI Connector; and SureStream Silicone Catheter; Codman and Shurtleff Inc., a Johnson & Johnson Company, Raynham, MA, USA) underwent evaluation for magnetic field interactions (deflection angle and torque), heating (transmit/receive body radiofrequency coil; whole-body averaged specific absorption rate, 3 W/kg for 15 min), functional changes (before and after MRI using eight different MRI conditions), and artifacts (T1-weighted spin-echo and gradient-echo pulse sequences) at 3-Tesla. Results.  The programmable infusion pump and associated catheters exhibited minor magnetic field interactions. Heating was not excessive (≤ 1.9°), especially considering the experimental conditions used for this evaluation (ie, relatively high radiofrequency power/specific absorption rate level and use of a nonperfused phantom). The function of three out of six pumps was temporarily altered by exposures to 3-Tesla MRI conditions. Reset was achieved in each case. Artifacts were relatively large for the pump and minor for the catheter. Conclusions.  The programmable infusion pump and catheters will not pose increased risk to a patient examined using 3-Tesla MRI as long as specific safety guidelines are followed, which includes interrogation of the pump post-MRI to ensure proper settings. Artifacts for the programmable infusion pump may impact the diagnostic use of MRI if the area of interest is in the same area or near the device.

  6. Filling a Conical Cavity

    NASA Astrophysics Data System (ADS)

    Nye, Kyle; Eslam-Panah, Azar

    2016-11-01

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

  7. Melatonin and Oral Cavity

    PubMed Central

    Cengiz, Murat İnanç; Cengiz, Seda; Wang, Hom-Lay

    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 proliferation of collagen and osseous tissue, and acts as a protector against cellular degeneration associated with aging and toxin exposure. Arising out of its antioxidant actions, melatonin protects against inflammatory processes and cellular damage caused by the toxic derivates of oxygen. As a result of these actions, melatonin may be useful as a coadjuvant in the treatment of certain conditions of the oral cavity. However, the most important effect of melatonin seems to result from its potent antioxidant, immunomodulatory, protective, and anticancer properties. Thus, melatonin could be used therapeutically for instance, locally, in the oral cavity damage of mechanical, bacterial, fungal, or viral origin, in postsurgical wounds caused by tooth extractions and other oral surgeries. Additionally, it can help bone formation in various autoimmunological disorders such as Sjorgen syndrome, in periodontal diseases, in toxic effects of dental materials, in dental implants, and in oral cancers. PMID:22792106

  8. 7-Tesla MRI demonstrates absence of structural lesions in patients with vestibular paroxysmia

    PubMed Central

    Rommer, Paulus S.; Wiest, Gerald; Kronnerwetter, Claudia; Zach, Heidemarie; Loader, Benjamin; Elwischger, Kirsten; Trattnig, Siegfried

    2015-01-01

    Vestibular parxoysmia (VP) is a rare vestibular disorder. A neurovascular cross-compression (NVCC) between the vestibulochochlear nerve and an artery seems to be responsible for short attacks of vertigo in this entity. An NVCC can be seen in up to every fourth subject. The significance of these findings is not clear, as not all subjects suffer from symptoms. The aim of the present study was to assess possible structural lesions of the vestibulocochlear nerve by means of high field magnetic resonance imaging (MRI), and whether high field MRI may help to differentiate symptomatic from asymptomatic subjects. 7 Tesla MRI was performed in six patients with VP and confirmed NVCC seen on 1.5 and 3.0 MRI. No structural abnormalities were detected in any of the patients in 7 Tesla MRI. These findings imply that high field MRI does not help to differentiate between symptomatic and asymptomatic NVCC and that the symptoms of VP are not caused by structural nerve lesions. This supports the hypothesis that the nystagmus associated with VP has to be conceived pathophysiologically as an excitatory vestibular phenomenon, being not related to vestibular hypofunction. 7 Tesla MRI outperforms conventional MRI in image resolution and may be useful in vestibular disorders. PMID:26106306

  9. An 8-GW long-pulse generator based on Tesla transformer and pulse forming network.

    PubMed

    Su, Jiancang; Zhang, Xibo; Li, Rui; Zhao, Liang; Sun, Xu; Wang, Limin; Zeng, Bo; Cheng, Jie; Wang, Ying; Peng, Jianchang; Song, Xiaoxin

    2014-06-01

    A long-pulse generator TPG700L based on a Tesla transformer and a series pulse forming network (PFN) is constructed to generate intense electron beams for the purpose of high power microwave (HPM) generation. The TPG700L mainly consists of a 12-stage PFN, a built-in Tesla transformer in a pulse forming line, a three-electrode gas switch, a transmission line with a trigger, and a load. The Tesla transformer and the compact PFN are the key technologies for the development of the TPG700L. This generator can output electrical pulses with a width as long as 200 ns at a level of 8 GW and a repetition rate of 50 Hz. When used to drive a relative backward wave oscillator for HPM generation, the electrical pulse width is about 100 ns on a voltage level of 520 kV. Factors affecting the pulse waveform of the TPG700L are also discussed. At present, the TPG700L performs well for long-pulse HPM generation in our laboratory.

  10. An 8-GW long-pulse generator based on Tesla transformer and pulse forming network

    SciTech Connect

    Su, Jiancang; Zhang, Xibo; Li, Rui; Zhao, Liang Sun, Xu; Wang, Limin; Zeng, Bo; Cheng, Jie; Wang, Ying; Peng, Jianchang; Song, Xiaoxin

    2014-06-15

    A long-pulse generator TPG700L based on a Tesla transformer and a series pulse forming network (PFN) is constructed to generate intense electron beams for the purpose of high power microwave (HPM) generation. The TPG700L mainly consists of a 12-stage PFN, a built-in Tesla transformer in a pulse forming line, a three-electrode gas switch, a transmission line with a trigger, and a load. The Tesla transformer and the compact PFN are the key technologies for the development of the TPG700L. This generator can output electrical pulses with a width as long as 200 ns at a level of 8 GW and a repetition rate of 50 Hz. When used to drive a relative backward wave oscillator for HPM generation, the electrical pulse width is about 100 ns on a voltage level of 520 kV. Factors affecting the pulse waveform of the TPG700L are also discussed. At present, the TPG700L performs well for long-pulse HPM generation in our laboratory.

  11. Assessment of MRI Issues at 3 Tesla for a New Metallic Tissue Marker.

    PubMed

    Cronenweth, Charlotte M; Shellock, Frank G

    2015-01-01

    Purpose. To assess the MRI issues at 3 Tesla for a metallic tissue marker used to localize removal areas of tissue abnormalities. Materials and Methods. A newly designed, metallic tissue marker (Achieve Marker, CareFusion, Vernon Hills, IL) used to mark biopsy sites, particularly in breasts, was assessed for MRI issues which included standardized tests to determine magnetic field interactions (i.e., translational attraction and torque), MRI-related heating, and artifacts at 3 Tesla. Temperature changes were determined for the marker using a gelled-saline-filled phantom. MRI was performed at a relatively high specific absorption rate (whole body averaged SAR, 2.9-W/kg). MRI artifacts were evaluated using T1-weighted, spin echo and gradient echo pulse sequences. Results. The marker displayed minimal magnetic field interactions (2-degree deflection angle and no torque). MRI-related heating was only 0.1°C above background heating (i.e., the heating without the tissue marker present). Artifacts seen as localized signal loss were relatively small in relation to the size and shape of the marker. Conclusions. Based on the findings, the new metallic tissue marker is acceptable or "MR Conditional" (using current labeling terminology) for a patient undergoing an MRI procedure at 3 Tesla or less.

  12. Focused tight dressing does not prevent cochlear implant magnet migration under 1.5 Tesla MRI.

    PubMed

    Cuda, D; Murri, A; Succo, G

    2013-04-01

    We report a retrospective case of inner magnet migration, which occurred after 1.5 Tesla MRI scanning in an adult recipient of a bilateral cochlear implant (CI) despite a focused head dressing. The patient, bilaterally implanted with Nucleus 5 CIs (Cochlear LTD, Sydney, Australia), underwent a 1.5 Tesla cholangio-MRI scan for biliary duct pathology. In subsequent days, a focal skin alteration appeared over the left inner coil. Plain skull radiographs showed partial magnet migration on the left side. Surgical exploration confirmed magnet twisting; the magnet was effectively repositioned. Left CI performance was restored to pre-migration level. The wound healed without complications. Thus, focused dressing does not prevent magnet migration in CI recipients undergoing 1.5 Tesla MRI. All patients should be counselled on this potential complication. A minor surgical procedure is required to reposition the magnet. Nevertheless, timely diagnosis is necessary to prevent skin breakdown and subsequent device contamination. Plain skull radiograph is very effective in identifying magnet twisting; it should be performed systematically after MRI or minimally on all suspected cases.

  13. 7-Tesla MRI demonstrates absence of structural lesions in patients with vestibular paroxysmia.

    PubMed

    Rommer, Paulus S; Wiest, Gerald; Kronnerwetter, Claudia; Zach, Heidemarie; Loader, Benjamin; Elwischger, Kirsten; Trattnig, Siegfried

    2015-01-01

    Vestibular parxoysmia (VP) is a rare vestibular disorder. A neurovascular cross-compression (NVCC) between the vestibulochochlear nerve and an artery seems to be responsible for short attacks of vertigo in this entity. An NVCC can be seen in up to every fourth subject. The significance of these findings is not clear, as not all subjects suffer from symptoms. The aim of the present study was to assess possible structural lesions of the vestibulocochlear nerve by means of high field magnetic resonance imaging (MRI), and whether high field MRI may help to differentiate symptomatic from asymptomatic subjects. 7 Tesla MRI was performed in six patients with VP and confirmed NVCC seen on 1.5 and 3.0 MRI. No structural abnormalities were detected in any of the patients in 7 Tesla MRI. These findings imply that high field MRI does not help to differentiate between symptomatic and asymptomatic NVCC and that the symptoms of VP are not caused by structural nerve lesions. This supports the hypothesis that the nystagmus associated with VP has to be conceived pathophysiologically as an excitatory vestibular phenomenon, being not related to vestibular hypofunction. 7 Tesla MRI outperforms conventional MRI in image resolution and may be useful in vestibular disorders.

  14. A Tesla-type repetitive nanosecond pulse generator for solid dielectric breakdown research.

    PubMed

    Zhao, Liang; Pan, Ya Feng; Su, Jian Cang; Zhang, Xi Bo; Wang, Li Min; Fang, Jin Peng; Sun, Xu; Lui, Rui

    2013-10-01

    A Tesla-type repetitive nanosecond pulse generator including a pair of electrode and a matched absorption resistor is established for the application of solid dielectric breakdown research. As major components, a built-in Tesla transformer and a gas-gap switch are designed to boost and shape the output pulse, respectively; the electrode is to form the anticipated electric field; the resistor is parallel to the electrode to absorb the reflected energy from the test sample. The parameters of the generator are a pulse width of 10 ns, a rise and fall time of 3 ns, and a maximum amplitude of 300 kV. By modifying the primary circuit of the Tesla transformer, the generator can produce both positive and negative pulses at a repetition rate of 1-50 Hz. In addition, a real-time measurement and control system is established based on the solid dielectric breakdown requirements for this generator. With this system, experiments on test samples made of common insulation materials in pulsed power systems are conducted. The preliminary experimental results show that the constructed generator is capable to research the solid dielectric breakdown phenomenon on a nanosecond time scale.

  15. Broadband cavity electromagnetically induced transparency

    SciTech Connect

    Wei Xiaogang; Wang Yanhua; Zhang Jiepeng; Zhu Yifu

    2011-10-15

    Cavity electromagnetically induced transparency (EIT) is created in a three-level atomic system confined in a cavity and coupled to a free-space control laser and is manifested as a narrow transmission peak of a probe laser coupled into the cavity mode and tuned to the two-photon Raman resonance with the control laser. Cavity EIT can be observed with a control laser detuned from the atomic transition frequency in a range limited by the vacuum Rabi splitting of two cavity-atom normal modes. This leads to the broadband cavity EIT obtained in the coupled-cavity-atom system with a free-space, broadband control laser. We report an experimental observation of broadband cavity EIT in cold Rb atoms with a frequency-modulated control laser and discuss its application in multichannel and multifrequency light memory.

  16. Single-cavity SLED device

    SciTech Connect

    Lippmann, B.A.

    1984-09-01

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

  17. [Myxofibrosarcoma in the abdominal cavity].

    PubMed

    Janů, F

    2016-01-01

    A number of benign and malignant tumors may develop in the abdominal cavity. Sarcomas are rather rare tumors of the abdominal cavity. They are often diagnosed at advanced growth stages as their local growth can cause clinical problems to the patients. The author presents a case report of myxofibrosarcoma in the abdominal cavity.Key words: myxofibrosarcoma.

  18. Hollow waveguide cavity ringdown spectroscopy

    NASA Technical Reports Server (NTRS)

    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.

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

    SciTech Connect

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

    2005-09-20

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

  20. CAVITY CONTROL ALGORITHM

    SciTech Connect

    Tomasz Plawski, J. Hovater

    2010-09-01

    A digital low level radio frequency (RF) system typically incorporates either a heterodyne or direct sampling technique, followed by fast ADCs, then an FPGA, and finally a transmitting DAC. This universal platform opens up the possibilities for a variety of control algorithm implementations. The foremost concern for an RF control system is cavity field stability, and to meet the required quality of regulation, the chosen control system needs to have sufficient feedback gain. In this paper we will investigate the effectiveness of the regulation for three basic control system algorithms: I&Q (In-phase and Quadrature), Amplitude & Phase and digital SEL (Self Exciting Loop) along with the example of the Jefferson Lab 12 GeV cavity field control system.

  1. Cavity enhanced atomic magnetometry.

    PubMed

    Crepaz, Herbert; Ley, Li Yuan; Dumke, Rainer

    2015-10-20

    Atom sensing based on Faraday rotation is an indispensable method for precision measurements, universally suitable for both hot and cold atomic systems. Here we demonstrate an all-optical magnetometer where the optical cell for Faraday rotation spectroscopy is augmented with a low finesse cavity. Unlike in previous experiments, where specifically designed multipass cells had been employed, our scheme allows to use conventional, spherical vapour cells. Spherical shaped cells have the advantage that they can be effectively coated inside with a spin relaxation suppressing layer providing long spin coherence times without addition of a buffer gas. Cavity enhancement shows in an increase in optical polarization rotation and sensitivity compared to single-pass configurations.

  2. Cavity enhanced atomic magnetometry

    PubMed Central

    Crepaz, Herbert; Ley, Li Yuan; Dumke, Rainer

    2015-01-01

    Atom sensing based on Faraday rotation is an indispensable method for precision measurements, universally suitable for both hot and cold atomic systems. Here we demonstrate an all-optical magnetometer where the optical cell for Faraday rotation spectroscopy is augmented with a low finesse cavity. Unlike in previous experiments, where specifically designed multipass cells had been employed, our scheme allows to use conventional, spherical vapour cells. Spherical shaped cells have the advantage that they can be effectively coated inside with a spin relaxation suppressing layer providing long spin coherence times without addition of a buffer gas. Cavity enhancement shows in an increase in optical polarization rotation and sensitivity compared to single-pass configurations. PMID:26481853

  3. RF Cavity Characterization with VORPAL

    SciTech Connect

    C. Nieter, C. Roark, P. Stoltz, C.D. Zhou, F. Marhauser

    2011-03-01

    When designing a radio frequency (RF) accelerating cavity structure various figures of merit are considered before coming to a final cavity design. These figures of merit include specific field and geometry based quantities such as the ratio of the shunt impedance to the quality factor (R/Q) or the normalized peak fields in the cavity. Other important measures of cavity performance include the peak surface fields as well as possible multipacting resonances in the cavity. High fidelity simulations of these structures can provide a good estimate of these important quantities before any cavity prototypes are built. We will present VORPAL simulations of a simple pillbox structure where these quantities can be calculated analytically and compare them to the results from the VORPAL simulations. We will then use VORPAL to calculate these figures of merit and potential multipacting resonances for two cavity designs under development at Jefferson National Lab for Project X.

  4. Crab Cavities for Linear Colliders

    SciTech Connect

    Burt, G.; Ambattu, P.; 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; /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.

  5. Simulation of RF Cavity Dark Current In Presence of Helical Magnetic Field

    SciTech Connect

    Romanov, Gennady; Kashikhin, Vladimir; /Fermilab

    2012-05-01

    In order to produce muon beam of high enough quality to be used for a Muon Collider, its large phase space must be cooled several orders of magnitude. This task can be accomplished by ionization cooling. Ionization cooling consists of passing a high-emittance muon beam alternately through regions of low Z material, such as liquid hydrogen, and very high accelerating RF cavities within a multi-Tesla solenoidal focusing channel. But first high power tests of RF cavity with beryllium windows in solenoidal magnetic field showed a dramatic drop in accelerating gradient due to RF breakdowns. It has been concluded that external magnetic fields parallel to RF electric field significantly modifies the performance of RF cavities. However, magnetic field in Helical Cooling Channel has a strong dipole component in addition to solenoidal one. The dipole component essentially changes electron motion in a cavity compare to pure solenoidal case, making dark current less focused at field emission sites. The simulation of dark current dynamic in HCC performed with CST Studio Suit is presented in this paper.

  6. Simulation of RF Cavity Dark Current in Presence of Helical Magnetic Field

    SciTech Connect

    Romanov, Gennady; Kashikhin, Vladimir; /Unlisted

    2010-09-01

    In order to produce muon beam of high enough quality to be used for a Muon Collider, its large phase space must be cooled several orders of magnitude. This task can be accomplished by ionization cooling. Ionization cooling consists of passing a high-emittance muon beam alternately through regions of low Z material, such as liquid hydrogen, and very high accelerating RF cavities within a multi-Tesla solenoidal focusing channel. But first high power tests of RF cavity with beryllium windows in solenoidal magnetic field showed a dramatic drop in accelerating gradient due to RF breakdowns. It has been concluded that external magnetic fields parallel to RF electric field significantly modifies the performance of RF cavities. However, magnetic field in Helical Cooling Channel has a strong dipole component in addition to solenoidal one. The dipole component essentially changes electron motion in a cavity compare to pure solenoidal case, making dark current less focused at field emission sites. The simulation of dark current dynamic in HCC performed with CST Studio Suit is presented in this paper.

  7. Tesla: An application for real-time data analysis in High Energy Physics

    NASA Astrophysics Data System (ADS)

    Aaij, R.; Amato, S.; Anderlini, L.; Benson, S.; Cattaneo, M.; Clemencic, M.; Couturier, B.; Frank, M.; Gligorov, V. V.; Head, T.; Jones, C.; Komarov, I.; Lupton, O.; Matev, R.; Raven, G.; Sciascia, B.; Skwarnicki, T.; Spradlin, P.; Stahl, S.; Storaci, B.; Vesterinen, M.

    2016-11-01

    Upgrades to the LHCb computing infrastructure in the first long shutdown of the LHC have allowed for high quality decay information to be calculated by the software trigger making a separate offline event reconstruction unnecessary. Furthermore, the storage space of the triggered candidate is an order of magnitude smaller than the entire raw event that would otherwise need to be persisted. Tesla is an application designed to process the information calculated by the trigger, with the resulting output used to directly perform physics measurements.

  8. Poly-coil design for a 60 tesla quasi-stationary magnet

    NASA Astrophysics Data System (ADS)

    Boenig, H. J.; Campbell, L. J.; Hodgdon, M. L.; Lopez, E. A.; Rickel, D. G.; Rogers, J. D.; Schillig, J. B.; Sims, J. R.; Pernambuco-Wise, P.; Schneider-Muntau, H. J.

    1993-02-01

    Among the new facilities to be offered by the National Science Foundation through the National High Magnetic Field Laboratory (NHMFL) are pulsed fields that can only be achieved at a national user facility by virtue of their strength, duration, and volume. In particular, a 44 mm bore pulsed magnet giving a 60 tesla field for 100 ms is in the final design stage. This magnet will be powered by a 1.4 GW motor-generator at Los Alamos and is an important step toward proving design principles that will be needed for the higher field quasi-stationary pulsed magnets that this power source is capable of driving.

  9. Experimental determination of magnetohydrodynamic seawater thruster performance in a two Tesla test facility

    SciTech Connect

    Picologlou, B.; Doss, E.; Black, D.; Sikes, W.C.

    1992-09-01

    A two Tesla test facility was designed, built, and operated to investigate the performance of magnetohydrodynamic (MHD) seawater thrusters. The results of this investigation are used to validate MHD thruster performance computer models. The facility test loop, its components, and their design are presented in detail. Additionally, the test matrix and its rational are discussed. finally, representative experimental results of the test program are presented, and are compared to pretest computer model predictions. Good agreement between predicted and measured data has served to validate the thruster performance computer models.

  10. Experimental determination of magnetohydrodynamic seawater thruster performance in a two Tesla test facility

    SciTech Connect

    Picologlou, B.; Doss, E.; Black, D. ); Sikes, W.C. )

    1992-01-01

    A two Tesla test facility was designed, built, and operated to investigate the performance of magnetohydrodynamic (MHD) seawater thrusters. The results of this investigation are used to validate MHD thruster performance computer models. The facility test loop, its components, and their design are presented in detail. Additionally, the test matrix and its rational are discussed. finally, representative experimental results of the test program are presented, and are compared to pretest computer model predictions. Good agreement between predicted and measured data has served to validate the thruster performance computer models.

  11. Experimental determination of magnetohydrodynamic seawater thruster performance in a two Tesla test facility

    NASA Astrophysics Data System (ADS)

    Picologlou, B.; Doss, E.; Black, D.; Sikes, W. C.

    1992-08-01

    A two Tesla test facility was designed, built, and operated to investigate the performance of magnetohydrodynamic (MHD) seawater thrusters. The results of this investigation are used to validate MHD thruster performance computer models. The facility test loop, its components, and their design are presented in detail. Additionally, the test matrix and its rational are discussed. Finally, representative experimental results of the test program are presented, and are compared to pretest computer model predictions. Good agreement between predicted and measured data has served to validate the thruster performance computer models.

  12. Science and Technology of the TESLA Electron-Positron Linear Collider

    NASA Astrophysics Data System (ADS)

    Wagner, Albrecht

    2002-07-01

    Recent analyses of the long term future of particles physics in Asia, Europe, and the U.S.A. have led to the consensus that the next major facility to be built to unravel the secrets of the micro-cosmos is an electron-positron linear collider in the energy range of 500 to 1000 GeV. This collider should be constructed in an as timely fashion as possible to overlap with the Large Hadron Collider, under construction at CERN. Here, the scientific potential and the technological aspects of the TESLA projects, a superconducting collider with an integrated X-ray laser laboratory, are summarised.

  13. 3.0 Tesla magnetic resonance imaging: A new standard in liver imaging?

    PubMed

    Girometti, Rossano

    2015-07-28

    An ever-increasing number of 3.0 Tesla (T) magnets are installed worldwide. Moving from the standard of 1.5 T to higher field strength implies a number of potential advantage and drawbacks, requiring careful optimization of imaging protocols or implementation of novel hardware components. Clinical practice and literature review suggest that state-of-the-art 3.0 T is equivalent to 1.5 T in the assessment of focal liver lesions and diffuse liver disease. Therefore, further technical improvements are needed in order to fully exploit the potential of higher field strength.

  14. Liquid neon heat transfer as applied to a 30 tesla cryomagnet

    NASA Technical Reports Server (NTRS)

    Papell, S. S.; Hendricks, R. C.

    1975-01-01

    A 30-tesla magnet design is studied which calls for forced convection liquid neon heat transfer in small coolant channels. The design also requires suppressing boiling by subjecting the fluid to high pressures through use of magnet coils enclosed in a pressure vessel which is maintained at the critical pressure of liquid neon. This high pressure reduces the possibility of the system flow instabilities which may occur at low pressures. The forced convection heat transfer data presented were obtained by using a blowdown technique to force the fluid to flow vertically through a resistance heated, instrumented tube.

  15. COMPARISON OF THE TESLA, NLC AND CLIC BEAM-COLLIMATION SYSTEM PERFORMANCE

    SciTech Connect

    Seryi, Andrei

    2003-05-28

    This report describes studies performed in the frame-work of the Collimation Task Force organized to support the work of the second International Linear Collider Technical Review Committee. The post-linac beam-collimation systems in the TESLA, JLC/NLC and CLIC linear-collider designs are compared using the same computer code under the same assumptions. Their performance is quantified in terms of beam-halo and synchrotron-radiation collimation efficiency. The performance of the current designs varies across projects, and does not always meet the original design goals. But these comparisons suggest that achieving the required performance in a future linear collider is feasible.

  16. Comparison of the TESLA, NLC and CLIC beam-collimation system performance

    SciTech Connect

    Alexandr I Drozhdin; Grahame Blair; Lewis P Keller

    2003-05-28

    This report describes studies performed in the framework of the Collimation Task Force organized to support the work of the International Linear Collider Technical Review Committee. The post-linac beam-collimation systems in the TESLA, JLC/NLC and CLIC linear-collider designs are compared using the same computer code under the same assumptions. Their performance is quantified in terms of beam-halo and synchrotron-radiation collimation efficiency. The performance of the current designs varies across projects, and does not always meet the original design goals. But these comparisons suggest that achieving the required performance in a future linear collider is feasible.

  17. Assessment of the immune responsiveness of mice exposed to a 1. 5-Tesla stationary magnetic field

    SciTech Connect

    Tenforde, T.S.; Shifrine, M.

    1984-01-01

    Humoral and cell-mediated immune responses were assayed following a 6-day exposure of LAF1/J mice to a 1.50 Tesla (1 T . 10(4) Gauss) stationary magnetic field. In tests of the immune response to sheep erythrocytes, the number of Jerne plaques formed by spleen lymphocytes and the level of serum IgM were not significantly different for the exposed mice in comparison with control animals. Tests for mitogen-induced lymphocyte proliferation also demonstrated no significant differences in the response of spleen lymphocytes from exposed and control groups of mice.

  18. 3.0 Tesla magnetic resonance imaging: A new standard in liver imaging?

    PubMed Central

    Girometti, Rossano

    2015-01-01

    An ever-increasing number of 3.0 Tesla (T) magnets are installed worldwide. Moving from the standard of 1.5 T to higher field strength implies a number of potential advantage and drawbacks, requiring careful optimization of imaging protocols or implementation of novel hardware components. Clinical practice and literature review suggest that state-of-the-art 3.0 T is equivalent to 1.5 T in the assessment of focal liver lesions and diffuse liver disease. Therefore, further technical improvements are needed in order to fully exploit the potential of higher field strength. PMID:26244063

  19. Cavity soliton billiards

    SciTech Connect

    Prati, F.; Lugiato, L. A.; Tissoni, G.; Brambilla, M.

    2011-11-15

    The motion of a self-propelled cavity soliton in a laser where the pump profile acts as a square billiard is investigated. In the long-term dynamics, only closed trajectories are possible, exhibiting nonspecular reflections with striking similarities to walking droplets in a vibrated liquid bath. Open orbits can be achieved either by introducing scattering defects in the pump profile or in the presence of more than two solitons, due to their interaction. Such dynamical properties can be exploited for applications such as a compact soliton-force microscope.

  20. Cavity optomechanical magnetometer.

    PubMed

    Forstner, S; Prams, S; Knittel, J; van Ooijen, E D; Swaim, J D; Harris, G I; Szorkovszky, A; Bowen, W P; Rubinsztein-Dunlop, H

    2012-03-23

    A cavity optomechanical magnetometer is demonstrated. The magnetic-field-induced expansion of a magnetostrictive material is resonantly transduced onto the physical structure of a highly compliant optical microresonator and read out optically with ultrahigh sensitivity. A peak magnetic field sensitivity of 400  nT  Hz(-1/2) is achieved, with theoretical modeling predicting the possibility of sensitivities below 1  pT  Hz(-1/2). This chip-based magnetometer combines high sensitivity and large dynamic range with small size and room temperature operation.

  1. Update on coaxial coupling scheme for International Linear Collider-type cavities

    SciTech Connect

    Peter Kneisel, Jacek Sekutowicz

    2010-02-17

    This paper reports on our efforts to develop a flangeable coaxial coupler for both higher order mode and fundamental coupling for nine-cell ILC-type cavities, which were designed in the early 1990’s for pulsed operation with a duty factor less than 1%. The design of the coupler has been done in such a way that the rf magnetic flux B at the flange connection was minimized and only a field of <5 mT would be present for an operation at an accelerating field Eacc~36 MV/m (B~150 mT) in the cavity. Even though we achieved reasonably high Q values at low field, the cavity/coupler combination was limited in the cw mode to only ~7 MV/m, where a thermally initiated degradation occurred. We believed that this limitation was caused by poor cooling of the shorting plate and inner tube in the coaxial coupler; therefore, we have improved the cooling conditions by initially drilling radial cooling channels every 30 degrees, then every 15 degrees into the shorting plate and eventually removing the “bridges” between the channels. This paper reports on our experiences with the modified coaxial coupler under cw and pulsed conditions.

  2. Applications of cavity optomechanics

    NASA Astrophysics Data System (ADS)

    Metcalfe, Michael

    2014-09-01

    "Cavity-optomechanics" aims to study the quantum properties of mechanical systems. A common strategy implemented in order to achieve this goal couples a high finesse photonic cavity to a high quality factor mechanical resonator. Then, using feedback forces such as radiation pressure, one can cool the mechanical mode of interest into the quantum ground state and create non-classical states of mechanical motion. On the path towards achieving these goals, many near-term applications of this field have emerged. After briefly introducing optomechanical systems and describing the current state-of-the-art experimental results, this article summarizes some of the more exciting practical applications such as ultra-sensitive, high bandwidth accelerometers and force sensors, low phase noise x-band integrated microwave oscillators and optical signal processing such as optical delay-lines, wavelength converters, and tunable optical filters. In this rapidly evolving field, new applications are emerging at a fast pace, but this article concentrates on the aforementioned lab-based applications as these are the most promising avenues for near-term real-world applications. New basic science applications are also becoming apparent such as the generation of squeezed light, testing gravitational theories and for providing a link between disparate quantum systems.

  3. JLEIC SRF cavity RF Design

    SciTech Connect

    Wang, Shaoheng; Guo, Jiquan; Wang, Haipeng; Rimmer, Robert A.

    2016-05-01

    The initial design of a low higher order modes (HOM) impedance superconducting RF (SRF) cavity is presented in this paper. The design of this SRF cavity is for the proposed Jefferson Lab Electron Ion Collider (JLEIC). The electron ring of JLEIC will operate with electrons of 3 to 10 GeV energy. The ion ring of JLEIC will operate with protons of up to 100 GeV energy. The bunch lengths in both rings are ~12 mm (RMS). In order to maintain the short bunch length in the ion ring, SRF cavities are adopted to provide large enough gradient. In the first phase of JLEIC, the PEP II RF cavities will be reused in the electron ring to lower the initial cost. The frequency of the SRF cavities is chosen to be the second harmonic of PEP II cavities, 952.6 MHz. In the second phase of JLEIC, the same frequency SRF cavities may replace the normal conducting PEP II cavities to achieve higher luminosity at high energy. At low energies, the synchro-tron radiation damping effect is quite weak, to avoid the coupled bunch instability caused by the intense closely-spaced electron bunches, low HOM impedance of the SRF cavities combined with longitudinal feedback sys-tem will be necessary.

  4. Nanofriction in Cavity Quantum Electrodynamics

    NASA Astrophysics Data System (ADS)

    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.

  5. Nanofriction in Cavity Quantum Electrodynamics.

    PubMed

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

    2015-12-04

    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.

  6. Cavity coalescence in superplastic deformation

    SciTech Connect

    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.

  7. Chemical exchange saturation transfer MR imaging of Parkinson’s disease at 3 Tesla

    PubMed Central

    Li, Chunmei; Peng, Shuai; Wang, Rui; Chen, Haibo; Su, Wen; Zhao, Xuna; Zhou, Jinyuan; Chen, Min

    2015-01-01

    Objectives To demonstrate the feasibility of using chemical exchange saturation transfer (CEST) imaging to detect Parkinson’s disease (PD) in patients at 3 Tesla. Methods Twenty-seven PD patients (17 men and 10 women; age range, 54–77 years) and 22 age-matched normal controls (13 men and 9 women; age range, 55–73 years) were examined on a 3-Tesla MRI system. Magnetization transfer spectra with 31 different frequency offsets (−6 to 6 ppm) were acquired at two transverse slices of the head, including the basal ganglia and midbrain. One-way analysis of variance tests was used to compare the differences in CEST imaging signals between PD patients and normal controls. Results Total CEST signal between the offsets of 0 and 4 ppm in the substantia nigra was significantly lower in PD patients than in normal controls (P=0.006), which could be associated with the loss of dopaminergic neurons. Protein-based CEST imaging signals at the offset of 3.5 ppm in the globus pallidus, putamen and caudate were significantly increased in PD patients, compared to normal controls (P<0.001, P=0.003, P<0.001, respectively). Conclusions CEST imaging signals could potentially serve as imaging biomarkers to aid in the non-invasive molecular diagnosis of PD. PMID:25038850

  8. 3D calculations of the Superconducting Super Collider (SSC) 3 Tesla magnet

    SciTech Connect

    Lari, R.J.

    1984-01-01

    A 20 TeV Superconducting Super Collider (SSC) proton accelerator is being proposed by the High Energy Physics Community. One proposal would consist of a ring of magnets 164 km in circumference with a field strength of 3 Tesla and would cost 2.7 billion dollars. The magnet consists of stacked steel laminations with superconducting coils. The desired field uniformity is obtained for all fields from 0.2 to 3 Tesla by using three (or more) different pole shapes. These three different laminations are stacked in the order 1-2-3-1-2-3-... creating a truly three dimensional geometry. A three laminated stack 1-2-3 with periodic boundary conditions at 1 and 3 was assigned about 5000 finite elements per lamination and solved using the computer program TOSCA. To check the TOSCA results, the field of each of the three different shaped laminations was calculated separately using periodic boundary conditions and compared to the two dimensional field calculations using TRIM. This was done for a constant permeability of 2000 and using the B-H table for fully annealed 1010 steel. The difference of the field calculations in the region of interest was always less than +-.2%

  9. In vivo sensitivity estimation and imaging acceleration with rotating RF coil arrays at 7 Tesla.

    PubMed

    Li, Mingyan; Jin, Jin; Zuo, Zhentao; Liu, Feng; Trakic, Adnan; Weber, Ewald; Zhuo, Yan; Xue, Rong; Crozier, Stuart

    2015-03-01

    Using a new rotating SENSitivity Encoding (rotating-SENSE) algorithm, we have successfully demonstrated that the rotating radiofrequency coil array (RRFCA) was capable of achieving a significant reduction in scan time and a uniform image reconstruction for a homogeneous phantom at 7 Tesla. However, at 7 Tesla the in vivo sensitivity profiles (B1(-)) become distinct at various angular positions. Therefore, sensitivity maps at other angular positions cannot be obtained by numerically rotating the acquired ones. In this work, a novel sensitivity estimation method for the RRFCA was developed and validated with human brain imaging. This method employed a library database and registration techniques to estimate coil sensitivity at an arbitrary angular position. The estimated sensitivity maps were then compared to the acquired sensitivity maps. The results indicate that the proposed method is capable of accurately estimating both magnitude and phase of sensitivity at an arbitrary angular position, which enables us to employ the rotating-SENSE algorithm to accelerate acquisition and reconstruct image. Compared to a stationary coil array with the same number of coil elements, the RRFCA was able to reconstruct images with better quality at a high reduction factor. It is hoped that the proposed rotation-dependent sensitivity estimation algorithm and the acceleration ability of the RRFCA will be particularly useful for ultra high field MRI.

  10. Encouraging a "Romantic Understanding" of Science: The Effect of the Nikola Tesla Story

    NASA Astrophysics Data System (ADS)

    Hadzigeorgiou, Yannis; Klassen, Stephen; Klassen, Cathrine Froese

    2012-08-01

    The purpose of this paper is to discuss and apply the notion of romantic understanding by outlining its features and its potential role in science education, to identify its features in the story of Nikola Tesla, and to describe an empirical study conducted to determine the effect of telling such a story to Grade 9 students. Elaborated features of the story are the humanization of meaning, an association with heroes and heroic qualities, the limits of reality and extremes of experience, a sense of wonder, and a contesting of conventions and conventional ideas. The study demonstrates the learning benefits of encouraging a romantic understanding through a story that is structured explicitly around the identified features, in this instance in the context of the production and transmission of alternating current electricity. Quantitative and qualitative analyses of journal entries showed that the group of students who were encouraged to understand the concept of alternating current romantically (the experimental group) became more involved with both the content and the context of the story than a comparison group of students who were taught the concept explicitly, without a context (the control group). The students in the experimental group also performed statistically better on a science-content test taken 1 week and again 8 weeks after the indicated teaching intervention. This finding, along with the content analyses of students' journals, provided evidence of romantic understanding of the science content for those students who listened to the Tesla story.

  11. Shock induced cavity collapse

    NASA Astrophysics Data System (ADS)

    Skidmore, Jonathan; Doyle, Hugo; Tully, Brett; Betney, Matthew; Foster, Peta; Ringrose, Tim; Ramasamy, Rohan; Parkin, James; Edwards, Tom; Hawker, Nicholas

    2016-10-01

    Results from the experimental investigation of cavity collapse driven by a strong planar shock (>6km/s) are presented. Data from high speed framing cameras, laser backlit diagnostics and time-resolved pyromety are used to validate the results of hydrodynamic front-tracking simulations. As a code validation exercise, a 2-stage light gas gun was used to accelerate a 1g Polycarbonate projectile to velocities exceeding 6km/s; impact with a PMMA target containing a gas filled void results in the formation of a strong shockwave with pressures exceeding 1Mbar. The subsequent phenomena associated with the collapse of the void and excitation of the inert gas fill are recorded and compared to simulated data. Variation of the mass density and atomic number of the gas fill is used to alter the plasma parameters furthering the extent of the code validation.

  12. A scanning cavity microscope

    PubMed Central

    Mader, Matthias; Reichel, Jakob; Hänsch, Theodor W.; Hunger, David

    2015-01-01

    Imaging 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 high-finesse scanning optical microcavity to demonstrate ultra-sensitive imaging. Harnessing multiple interactions of probe light with a sample within an optical resonator, we achieve a 1,700-fold signal enhancement compared with diffraction-limited microscopy. We demonstrate quantitative imaging of the extinction cross-section of gold nanoparticles with a sensitivity less than 1 nm2; we show a method to improve the 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 optical studies of nanomaterials, molecules and biological nanosystems. PMID:26105690

  13. Quench studies of ILC cavities

    SciTech Connect

    Eremeev, Grigory; Geng, Rongli; Palczewski, Ari; Dai, Jin

    2011-07-01

    Quench limits accelerating gradient in SRF cavities to a gradient lower than theoretically expected for superconducting niobium. Identification of the quenching site with thermometry and OST, optical inspection, and replica of the culprit is an ongoing effort at Jefferson Lab aimed at better understanding of this limiting phenomenon. In this contribution we present our finding with several SRF cavities that were limited by quench.

  14. Superconducting Storage Cavity for RHIC

    SciTech Connect

    Ben-Zvi,I.

    2009-01-02

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

  15. Monochromatic radio frequency accelerating cavity

    DOEpatents

    Giordano, Salvatore

    1985-01-01

    A radio frequency resonant cavity having a fundamental resonant frequency and characterized by being free of spurious modes. A plurality of spaced electrically conductive bars are arranged in a generally cylindrical array within the cavity to define a chamber between the bars and an outer solid cylindrically shaped wall of the cavity. A first and second plurality of mode perturbing rods are mounted in two groups at determined random locations to extend radially and axially into the cavity thereby to perturb spurious modes and cause their fields to extend through passageways between the bars and into the chamber. At least one body of lossy material is disposed within the chamber to damp all spurious modes that do extend into the chamber thereby enabling the cavity to operate free of undesired spurious modes.

  16. Monochromatic radio frequency accelerating cavity

    DOEpatents

    Giordano, S.

    1984-02-09

    A radio frequency resonant cavity having a fundamental resonant frequency and characterized by being free of spurious modes. A plurality of spaced electrically conductive bars are arranged in a generally cylindrical array within the cavity to define a chamber between the bars and an outer solid cylindrically shaped wall of the cavity. A first and second plurality of mode perturbing rods are mounted in two groups at determined random locations to extend radially and axially into the cavity thereby to perturb spurious modes and cause their fields to extend through passageways between the bars and into the chamber. At least one body of lossy material is disposed within the chamber to damp all spurious modes that do extend into the chamber thereby enabling the cavity to operate free of undesired spurious modes.

  17. Mechanical Properties of Niobium Cavities

    SciTech Connect

    Ciovati, Gianluigi; Dhakal, Pashupati; Matalevich, Joseph R.; Myneni, Ganapati Rao

    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.

  18. Design and simulation of 3½-cell superconducting gun cavity and beam dynamics studies of the SASE-FEL System at the Institute of Accelerator Technologies at Ankara University

    NASA Astrophysics Data System (ADS)

    Yildiz, H. Duran; Cakir, R.; Porsuk, D.

    2015-06-01

    Design and simulation of a superconducting gun cavity with 3½ cells have been studied in order to give the first push to the electron beam for the linear accelerating system at The Institute of Accelerator Technologies at Ankara University. Electrons are accelerated through the gun cavity with the help of the Radiofrequency power suppliers from cryogenic systems. Accelerating gradient should be as high as possible to accelerate electron beam inside the cavity. In this study, electron beam reaches to 9.17 MeV energy at the end of the gun cavity with the accelerating gradient; Ec=19.21 MV/m. 1.3 GHz gun cavity consists of three TESLA-like shaped cells while the special designed gun-cell includes a cathode plug. Optimized important beam parameters inside the gun cavity, average beam current 3 mA, transverse emittance 2.5 mm mrad, repetition rate 30 MHz and other parameters are obtained for the SASE-FEL System. The Superfish/Poisson program is used to design each cell of the superconducting cavity. Superconducting gun cavity and Radiofrequency properties are studied by utilizing 2D Superfish/Poisson, 3D Computer Simulation Technology Microwave Studio, and 3D Computer Simulation Technology Particle Studio. Superfish/Poisson is also used to optimize the geometry of the cavity cells to get the highest accelerating gradient. The behavior of the particles along the beamline is included in this study. ASTRA Code is used to track the particles.

  19. 77 FR 2269 - Foreign-Trade Zone 18-San Jose, CA, Application for Subzone, Tesla Motors, Inc. (Electric...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-17

    ... the foreign components used in export production. The company anticipates that 40 to 65 percent of the... procedures. Customs duties also could possibly be deferred or reduced on foreign status production equipment. Tesla would also be exempt from duty payments on foreign inputs that become scrap during the...

  20. Comparison of different undulator schemes with superimposed alternating gradients for the VUV-FEL at the TESLA Test Facility

    SciTech Connect

    Pflueger, J.; Nikitina, Y.M.

    1995-12-31

    For the VUV-FEL at the TESLA Test Facility an undulator with a total length of 30 m is needed. In this study three different approaches to realize an undulator with a sinusoidal plus a superimposed quadrupolar field were studied with the 3D code MAFIA.

  1. Recurrent ulnar nerve entrapment at the elbow: Correlation of surgical findings and 3-Tesla magnetic resonance neurography.

    PubMed

    Chhabra, Avneesh; Wadhwa, Vibhor; Thakkar, Rashmi S; Carrino, John A; Dellon, A Lee

    2013-01-01

    The authors describe the correlation between 3-Tesla magnetic resonance neurography (MRN) and surgical findings in two patients who underwent multiple previous failed ulnar nerve surgeries. MRN correctly localized the site of the abnormality. Prospectively observed MRN findings of perineural fibrosis, ulnar nerve re-entrapment abnormalities, medial antebrachial cutaneous neuroma and additional median nerve entrapment were confirmed surgically.

  2. Human in vivo cardiac phosphorus NMR spectroscopy at 3.0 Tesla

    NASA Astrophysics Data System (ADS)

    Bruner, Angela Properzio

    One of the newest methods with great potential for use in clinical diagnosis of heart disease is human, cardiac, phosphorus NMR spectroscopy (cardiac p 31 MRS). Cardiac p31 MRS is able to provide quantitative, non-invasive, functional information about the myocardial energy metabolites such as pH, phosphocreatine (PCr), and adenosinetriphosphate (ATP). In addition to the use of cardiac p3l MRS for other types of cardiac problems, studies have shown that the ratio of PCr/ATP and pH are sensitive and specific markers of ischemia at the myocardial level. In human studies, typically performed at 1.5 Tesla, PCr/ATP has been relatively easy to measure but often requires long scan times to provide adequate signal-to-noise (SNR). In addition, pH which relies on identification of inorganic phosphate (Pi), has rarely been obtained. Significant improvement in the quality of cardiac p31 MRS was achieved through the use of the General Electric SIGNATM 3.0 Tesla whole body magnet, improved coil designs and optimized pulse sequences. Phantom and human studies performed on many types of imaging and spectroscopy sequences, identified breathhold gradient-echo imaging and oblique DRESS p31 spectroscopy as the best compromises between SNR, flexibility and quality localization. Both single-turn and quadrature 10-cm diameter, p31 radiofrequency coils, were tested with the quadrature coil providing greater SNR, but at a greater depth to avoid skeletal muscle contamination. Cardiac p31 MRS obtained in just 6 to 8 minutes, gated, showed both improved SNR and discernment of Pi allowing for pH measurement. A handgrip, in-magnet exerciser was designed, created and tested at 1.5 and 3.0 Tesla on volunteers and patients. In ischemic patients, this exercise was adequate to cause a repeated drop in PCr/ATP and pH with approximately eight minutes of isometric exercise at 30% maximum effort. As expected from literature, this exercise did not cause a drop in PCr/ATP for reference volunteers.

  3. Role of MRI in Evaluation of Malignant Lesions of Tongue and Oral Cavity

    PubMed Central

    Singh, Amandeep; Thukral, Chuni Lal; Gupta, Kamlesh; Sood, Arvinder Singh; Singla, Hanish; Singh, Kunwarpal

    2017-01-01

    Summary Background Aim of the present study was to evaluate the role of MRI in staging of malignant lesions of the oral cavity and to correlate MRI findings with clinical/surgical and anatomical-pathological findings, wherever possible. Material/Methods The study included 50 patients who presented with malignant lesions of the oral cavity and were referred to radiology departments for MRI. All patients included were subjected to a detailed physical examination following which MRI was carried out on Philips Gyroscan Achieva 1.5 Tesla unit. Results In the study, the highest number of patients were found to have tongue malignancy (82%) followed by buccal mucosa and gingivobuccal sulcus malignancy (18%). The highest number of patients was in the age group of 51–60 years (32%). The incidence was higher in males (96%). There was moderate agreement (k=0.537) for T stage between the clinical and MRI staging assessments. The agreement for N stage between clinical and MRI staging assessments was fair (k=0.328). The final diagnosis was made by histopathology in 22 patients. The agreement for T stage was good/substantial (k=0.790) and for N stage was moderate (k=0.458) between MRI and histopathology staging assessments. Conclusions MRI provides satisfactory accuracy for preoperative estimation of tumor thickness and predicting occult cervical nodal metastasis. MRI is the preferred modality in evaluation and staging of oral cavity malignancy which helps a clinician for planning of treatment. PMID:28289481

  4. Laser Scanner for Tile-Cavity Measurement

    NASA Technical Reports Server (NTRS)

    Yoshino, Stanley Y.; Wykes, Donald H.; Hagen, George R.; Lotgering, Gene E.; Gaynor, Michael B.; Westerlund, Paul G.; Baal, Thomas A.

    1987-01-01

    Irregular surfaces mapped and digitized for numerical-control machinery. Fast, accurate laser scanning system measures size and shape of cavity without making any physical contact with cavity and walls. Measurements processed into control signals for numerically controlled machining of tile or block to fit cavity. System generates map of grid points representing cavity and portion of outer surface surrounding cavity. Map data used to control milling machine, which cuts tile or block to fit in cavity.

  5. Frequency-feedback cavity enhanced spectrometer

    DOEpatents

    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.

  6. Impairment of chondrocyte biosynthetic activity by exposure to 3-tesla high-field magnetic resonance imaging is temporary.

    PubMed

    Sunk, Ilse-Gerlinde; Trattnig, Siegfried; Graninger, Winfried B; Amoyo, Love; Tuerk, Birgit; Steiner, Carl-Walter; Smolen, Josef S; Bobacz, Klaus

    2006-01-01

    The influence of magnetic resonance imaging (MRI) devices at high field strengths on living tissues is unknown. We investigated the effects of a 3-tesla electromagnetic field (EMF) on the biosynthetic activity of bovine articular cartilage. Bovine articular cartilage was obtained from juvenile and adult animals. Whole joints or cartilage explants were subjected to a pulsed 3-tesla EMF; controls were left unexposed. Synthesis of sulfated glycosaminoglycans (sGAGs) was measured by using [35S]sulfate incorporation; mRNA encoding the cartilage markers aggrecan and type II collagen, as well as IL-1beta, were analyzed by RT-PCR. Furthermore, effects of the 3-tesla EMF were determined over the course of time directly after exposure (day 0) and at days 3 and 6. In addition, the influence of a 1.5-tesla EMF on cartilage sGAG synthesis was evaluated. Chondrocyte cell death was assessed by staining with Annexin V and TdT-mediated dUTP nick end labelling (TUNEL). Exposure to the EMF resulted in a significant decrease in cartilage macromolecule synthesis. Gene expression of both aggrecan and IL-1beta, but not of collagen type II, was reduced in comparison with controls. Staining with Annexin V and TUNEL revealed no evidence of cell death. Interestingly, chondrocytes regained their biosynthetic activity within 3 days after exposure, as shown by proteoglycan synthesis rate and mRNA expression levels. Cartilage samples exposed to a 1.5-tesla EMF remained unaffected. Although MRI devices with a field strength of more than 1.5 T provide a better signal-to-noise ratio and thereby higher spatial resolution, their high field strength impairs the biosynthetic activity of articular chondrocytes in vitro. Although this decrease in biosynthetic activity seems to be transient, articular cartilage exposed to high-energy EMF may become vulnerable to damage.

  7. Nonlocal Intracranial Cavity Extraction

    PubMed Central

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

    2014-01-01

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

  8. Composite resonator vertical cavity laser diode

    SciTech Connect

    Choquette, K.D.; Hou, H.Q.; Chow, W.W.; Geib, K.M.; Hammons, B.E.

    1998-05-01

    The use of two coupled laser cavities has been employed in edge emitting semiconductor lasers for mode suppression and frequency stabilization. The incorporation of coupled resonators within a vertical cavity laser opens up new possibilities due to the unique ability to tailor the interaction between the cavities. Composite resonators can be utilized to control spectral and temporal properties within the laser; previous studies of coupled cavity vertical cavity lasers have employed photopumped structures. The authors report the first composite resonator vertical cavity laser diode consisting of two optical cavities and three monolithic distributed Bragg reflectors. Cavity coupling effects and two techniques for external modulation of the laser are described.

  9. Cavity-state preparation using adiabatic transfer

    NASA Astrophysics Data System (ADS)

    Larson, Jonas; Andersson, Erika

    2005-05-01

    We show how to prepare a variety of cavity field states for multiple cavities. The state preparation technique used is related to the method of stimulated adiabatic Raman passage. The cavity modes are coupled by atoms, making it possible to transfer an arbitrary cavity field state from one cavity to another and also to prepare nontrivial cavity field states. In particular, we show how to prepare entangled states of two or more cavities, such as an Einstein-Podolsky-Rosen state and a W state, as well as various entangled superpositions of coherent states in different cavities, including Schrödinger cat states. The theoretical considerations are supported by numerical simulations.

  10. Optical Signatures from Magnetic 2-D Electron Gases in High Magnetic Fields to 60 Tesla

    SciTech Connect

    Crooker, S.A.; Kikkawa, J.M.; Awschalom, D.D.; Smorchikova, I.P.; Samarth, N.

    1998-11-08

    We present experiments in the 60 Tesla Long-Pulse magnet at the Los Alamos National High Magnetic Field Lab (NHMFL) focusing on the high-field, low temperature photoluminescence (PL) from modulation-doped ZnSe/Zn(Cd,Mn)Se single quantum wells. High-speed charge-coupled array detectors and the long (2 second) duration of the magnet pulse permit continuous acquisition of optical spectra throughout a single magnet shot. High-field PL studies of the magnetic 2D electron gases at temperatures down to 350mK reveal clear intensity oscillations corresponding to integer quantum Hall filling factors, from which we determine the density of the electron gas. At very high magnetic fields, steps in the PL energy are observed which correspond to the partial unlocking of antiferromagnetically bound pairs of Mn2+ spins.

  11. D-zero rototrack: first stage of D-zero 2 Tesla solenoid field mapping device

    SciTech Connect

    Yamada, R.; Korienek, J.; Krider, J.; Lindenmeyer, C.; Miksa, D.; Miksa, R.

    1997-09-01

    A simple and portable field mapping device was developed at Fermilab and successfully used to test the D0 2 Tesla solenoid at Toshiba Works in Japan. A description of the mechanical structure, electric driving and control system, and software of the field mapping device is given. Four Hall probe elements of Group3 Digital Gaussmeters are mounted on the radial extension arm of a carriage, which is mounted on a central rotating beam. The system gives two dimensional motions (axial and rotational) to the Hall probes. To make the system compact and portable, we used a laptop computer with PCMCIA cards. For the control system we used commercially available software LabVIEW and Motion Toolbox, and for the data analysis we used Microsoft Excel.

  12. A test of a 2 Tesla superconducting transmission line magnet system

    SciTech Connect

    Piekarz, Henryk; Carcagno, Ruben; Claypool, Brad; Foster, George W.; Hays, Steven L.; Huang, Yuenian; Kashikhin, Vladimir; Malamud, Ernest; Mazur, Peter O.; Nehring, Roger; Oleck, Andrew; Rabehl, Roger; Schlabach, Phil; Sylvester, Cosmore; Velev, Gueorgui; Volk, James; Wake, Masayoshi; /KEK, Tsukuba

    2005-09-01

    Superconducting transmission line magnet test system for an injector accelerator of a staged VLHC proton-proton colliding beam accelerator has been built and operated at Fermilab. The 1.5 m long, twin-aperture, combined function dipole magnet of 2 Tesla field is excited by a single turn 100 kA transmission line superconductor. The 100 kA dc current is generated using dc-dc switching converters powered by a bulk 240 kW supply. A pair of horizontally placed conventional leads facilitates transfer of this current to the magnet transmission line superconductor operating at liquid helium temperature. Fabrication of magnet components and magnet assembly work are described. The magnet test system and its operation are presented, and the performance is summarized.

  13. Preattentive mechanisms of change detection in early auditory cortex: a 7 Tesla fMRI study.

    PubMed

    Szycik, G R; Stadler, J; Brechmann, A; Münte, T F

    2013-12-03

    The auditory system continuously monitors the environment for irregularities in an automatic, preattentive fashion. This is presumably accomplished by two mechanisms: a sensory mechanism detects a deviant sound on the basis of differential refractoriness of neural populations sensitive to the standard and deviant sounds, whereas the cognitive mechanism reveals deviance by comparing incoming auditory information with a template derived from previous input. Using fast event-related high-resolution functional magnetic resonance imaging at 7 Tesla we show that both mechanisms can be mapped to different parts of the auditory cortex both at the group level and the single-subject level. The sensory mechanism is supported by primary auditory areas in Heschl's gyrus whereas the cognitive mechanism is implemented in more anterior secondary auditory areas. Both mechanisms are equally engaged by simple sine-wave tones and speech-related phonemes indicating that streams of speech and non-speech stimuli are processed in a similar fashion.

  14. Fabrication and characterization of a MEMS nano-Tesla ferromagnetic-piezoelectric magnetic sensor array

    NASA Astrophysics Data System (ADS)

    Qu, Peng; Gollapudi, Sreenivasulu; Bidthanapally, Rao; Srinivasan, Gopalan; Petrov, Vladimir; Qu, Hongwei

    2016-06-01

    A self-biased MEMS magnetic sensor array with ferromagnetic-piezoelectric composites has been fabricated and characterized. The array with two Quartz-Nickel-Metglas cantilevers with nano-tesla sensitivity was fabricated by MEMS processes including silicon-quartz low temperature bonding, quartz wafer thinning, and electroplating of thick nickel thin films. Under self-biasing due to magnetization grading of ferromagnetic layer, magnetoelectric coefficients of 6.6 and 5.6 V/cm Oe and resolutions of ˜0.58 and ˜0.75 nT are obtained at the mechanical resonant frequencies of 191.5 and 184.8 Hz for the two sensors in the array, respectively. Such arrays have the potential for applications in biomagnetic imaging technologies including magneto-cardiography.

  15. Shot noise startup of the 6 NM SASE FEL at the Tesla Test Facility

    SciTech Connect

    Pierini, P.; Fawley, W.M.

    1995-12-31

    We present here an analysis of the shot noise startup of the 6 nm SASE FEI proposal at the TESLA Test Facility in DESY The statistical of the saturation length and output power due to the intrinsic randomness of the noise startup are investigated with the use of the 2D time dependent code GINGER, that takes into account propagation effects and models shot noise. We then provide estimates for the spectral contents and linewidth of the emitted radiation and describe its spiking characteristics. The output radiation will develop superradiant spikes seeded by the shot noise in the electron beam, which can entrance the average emitted power at the expense of some spectral broadening.

  16. Current Progress in Fabrication of a 14 Tesla Nb3Sn Dipole

    NASA Astrophysics Data System (ADS)

    Holik, Eddie, III; Benson, Christopher; Damborsky, Kyle; Diaczenko, Nick; Elliott, Tim; Garrison, Ray; Jaisle, Andrew; McInturff, Alfred; McIntyre, Peter; Sattarov, Dior

    2012-03-01

    The Accelerator Technology Laboratory at Texas A&M is fabricating a model dipole magnet, TAMU3, designed to operate at a 14 Tesla bore field. The dipole employs an advanced internal-tin Nb3Sn/Cu composite strand with enhanced current density. The coils must be processed through a heat treatment after winding, during which the Sn within the heterogeneous strands diffuse into the Cu/Nb matrix to form high-performance superconducting layers. Heat treatment of the first coil assembly revealed tin leakage from the Sn cores that was caused by omission of a pre-anneal step in the heat treatment. We are evaluating the electrical properties of the coil, the microstructure and short-sample superconducting performance of cut-off samples of current leads to determine the extent of damage to the performance of the windings. Results of those tests and plans for construction of TAMU3 will be presented.

  17. Parameter study of the VUV-FEL at the Tesla Test Facility

    SciTech Connect

    Brefeld, W.; Faatz, B.

    1995-12-31

    In this contribution we present a detailed study of the influence of the electron beam and machine parameters on the performance of the TTF VUV FEL, which is in its design stage at DESY. The TTF FEL will be a 6 nm SASE device operating with the beam provided by the Tesla Test Facility superconducting linac, driven by an rf photcathode gun. The FEL output power and saturation length have been assessed with the use of different 2D3-D steady state simulation codes. The parameter range over which the FEL would reach saturation within the specified undulator length of 25 to 30 m have been determined and checked against semi-analytical expressions.

  18. GRASE imaging at 3 Tesla with template interactive phase-encoding.

    PubMed

    Jovicich, J; Norris, D G

    1998-06-01

    A new method for ordering the phase-encoding gradient is proposed, and an application for short effective TE gradient- and spin-echo (GRASE) imaging is demonstrated. The proposed method calculates the phase-encoding order from the signal decay of a template scan (hence "template interactive phase-encoding" or TIPE). Computer simulations are used to compare the point spread functions of different phase-encoding orders giving short effective echo times (kb centric GRASE, centric GRASE, centric TIPE). The conventional centric phase-encoding order is also considered for GRASE. The conventional centric method is sensitive to both amplitude and phase modulation of the signal in k-space. The centric TIPE method gives the least amplitude modulation artifacts but is vulnerable to phase artifacts. The TIPE experiment was implemented on a 3 Tesla system. To the best of our knowledge, we present the first in vivo GRASE images at this field strength.

  19. Design of the superconducting magnet for 9.4 Tesla whole-body magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Li, Y.; Wang, Q.; Dai, Y.; Ni, Z.; Zhu, X.; Li, L.; Zhao, B.; Chen, S.

    2017-02-01

    A superconducting magnet for 9.4 Tesla whole-body magnetic resonance imaging is designed and fabricated in Institute of Electrical Engineering, Chinese Academy of Sciences. In this paper, the electromagnetic design methods of the main coils and compensating coils are presented. Sensitivity analysis is performed for all superconducting coils. The design of the superconducting shimming coils is also presented and the design of electromagnetic decoupling of the Z2 coils from the main coils is introduced. Stress and strain analysis with both averaged and detailed models is performed with finite element method. A quench simulation code with anisotropic continuum model and control volume method is developed by us and is verified by experimental study. By means of the quench simulation code, the quench protection system for the 9.4 T magnet is designed for the main coils, the compensating coils and the shimming coils. The magnet cryostat design with zero helium boiling-off technology is also introduced.

  20. LEFT VERSUS RIGHT HEMISPHERE DIFFERENCES IN BRAIN CONNECTIVITY: 4-TESLA HARDI TRACTOGRAPHY IN 569 TWINS.

    PubMed

    Daianu, Madelaine; Jahanshad, Neda; Dennis, Emily L; Toga, Arthur W; McMahon, Katie L; de Zubicaray, Greig I; Martin, Nicholas G; Wright, Margaret J; Hickie, Ian B; Thompson, Paul M

    2012-05-01

    Diffusion imaging can map anatomical connectivity in the living brain, offering new insights into fundamental questions such as how the left and right brain hemispheres differ. Anatomical brain asymmetries are related to speech and language abilities, but less is known about left/right hemisphere differences in brain wiring. To assess this, we scanned 457 young adults (age 23.4±2.0 SD years) and 112 adolescents (age 12-16) with 4-Tesla 105-gradient high-angular resolution diffusion imaging. We extracted fiber tracts throughout the brain with a Hough transform method. A 70×70 connectivity matrix was created, for each subject, based on the proportion of fibers intersecting 70 cortical regions. We identified significant differences in the proportions of fibers intersecting left and right hemisphere cortical regions. The degree of asymmetry in the connectivity matrices varied with age, as did the asymmetry in network topology measures such as the small-world effect.

  1. Magnet Design and Analysis of a 40 Tesla Long Pulse System Energized by a Battery Bank

    NASA Astrophysics Data System (ADS)

    Lv, Y. L.; Peng, T.; Wang, G. B.; Ding, T. H.; Han, X. T.; Pan, Y.; Li, L.

    2013-03-01

    A 40 tesla long pulse magnet and a battery bank as the power supply have been designed. This is now under construction at the Wuhan National High Magnetic Field Center. The 22 mm bore magnet will generate smooth pulses with duration 1 s and rise time 0.5 s. The battery bank consists of 945 12V/200 Ah lead-acid battery cells. The magnet and battery bank were optimized by codes developed in-house and by ANSYS. The coil was made from soft copper with internal reinforcement by fiber-epoxy composite; it is divided into two sections connected in series. The inner section consists of helix coils with each layer reinforced by Zylon composite. The outer section will be wound from copper sheet and externally reinforced by carbon fiber composite.

  2. Comparison of the TESLA, NLC and CLIC Beam Collimation Systems Performance

    SciTech Connect

    Keller, Lewis P

    2003-03-27

    This note describes studies performed in the framework of the Collimation Task Force organized to support the work of the International Linear Collider Technical Review Committee. The post-linac beam-collimation systems in the TESLA, JLC/NLC and CLIC linear-collider designs are compared using the same computer code under the same assumptions. Their performance is quantified in terms of beam-halo and synchrotron-radiation collimation efficiency. The performance of the current designs varies across projects and does not always meet the original design goals. However, these comparisons suggest that achieving the required performance in a future linear collider is feasible. The post-TRC plans of the Collimation Task Force are outlined briefly in closing.

  3. Acoustic confinement in superlattice cavities

    NASA Astrophysics Data System (ADS)

    Garcia-Sanchez, Daniel; Déleglise, Samuel; Thomas, Jean-Louis; Atkinson, Paola; Lagoin, Camille; Perrin, Bernard

    2016-09-01

    The large coupling rate between the acoustic and optical fields confined in GaAs/AlAs superlattice cavities makes them appealing systems for cavity optomechanics. We have developed a mathematical model based on the scattering matrix that allows the acoustic guided modes to be predicted in nano and micropillar superlattice cavities. We demonstrate here that the reflection at the surface boundary considerably modifies the acoustic quality factor and leads to significant confinement at the micropillar center. Our mathematical model also predicts unprecedented acoustic Fano resonances on nanopillars featuring small mode volumes and very high mechanical quality factors, making them attractive systems for optomechanical applications.

  4. Novel Crab Cavity RF Design

    SciTech Connect

    Dudas, A.; Neubauer, M. L.; Sah, R.; Rimmer, B.; Wang, H.

    2011-03-01

    A 20-50 MV integrated transverse voltage is required for the Electron-Ion Collider. The most promising of the crab cavity designs that have been proposed in the last five years are the TEM type crab cavities because of the higher transverse impedance. The TEM design approach is extended here to a hybrid crab cavity that includes the input power coupler as an integral part of the design. A prototype was built with Phase I monies and tested at JLAB. The results reported on, and a system for achieving 20-50 MV is proposed.

  5. Low-noise nano superconducting quantum interference device operating in Tesla magnetic fields.

    PubMed

    Schwarz, Tobias; Nagel, Joachim; Wölbing, Roman; Kemmler, Matthias; Kleiner, Reinhold; Koelle, Dieter

    2013-01-22

    Superconductivity in the cuprate YBa(2)Cu(3)O(7) (YBCO) persists up to huge magnetic fields (B) up to several tens of Teslas, and sensitive direct current (dc) superconducting quantum interference devices (SQUIDs) can be realized in epitaxially grown YBCO films by using grain boundary Josephson junctions (GBJs). Here we present the realization of high-quality YBCO nanoSQUIDs, patterned by focused ion beam milling. We demonstrate low-noise performance of such a SQUID up to B = 1 T applied parallel to the plane of the SQUID loop at the temperature T = 4.2 K. The GBJs are shunted by a thin Au layer to provide nonhysteretic current voltage characteristics, and the SQUID incorporates a 90 nm wide constriction which is used for on-chip modulation of the magnetic flux through the SQUID loop. The white flux noise of the device increases only slightly from 1.3 μΦ(0)/(Hz)(1/2) at B = 0 to 2.3 μΦ(0)/(Hz))(1/2) at 1 T. Assuming that a point-like magnetic particle with magnetization in the plane of the SQUID loop is placed directly on top of the constriction and taking into account the geometry of the SQUID, we calculate a spin sensitivity S(μ)(1/2) = 62 μ(B)/(Hz))(1/2) at B = 0 and 110 μ(B)/(Hz))(1/2) at 1 T. The demonstration of low noise of such a SQUID in Tesla fields is a decisive step toward utilizing the full potential of ultrasensitive nanoSQUIDs for direct measurements of magnetic hysteresis curves of magnetic nanoparticles and molecular magnets.

  6. Magnetic Texture & Frustration in Quantum Magnets via Strain Measurements to 100 Tesla

    NASA Astrophysics Data System (ADS)

    Jaime, Marcelo

    2014-03-01

    Strong geometrical frustration in magnets leads to exotic states, such as spin liquids, spin supersolids, magnetic solitons, and complex magnetic textures. SrCu2(BO3)2 , a spin-1/2 Heisenberg antiferromagnet in the archetypical Shastry-Sutherland lattice, exhibits a rich spectrum of magnetization plateaus and stripe-like magnetic textures in applied fields. We observed new magnetic textures via optical FBG magnetostriction and magnetocaloric measurements in fields up to 100.75 Tesla at 73.6 T and at 82 T which we attribute, using a controlled density matrix renormalization group approach, to a 2/5 plateau and to the long-predicted 1/2-saturation plateau. The plateau predicted at 2/5 saturation is particularly interesting since strain appears to be the only experimental probe with enough sensitivity to reveal it as magnetization probes see a much more gradual change in the same field range. BiCu2PO6 is a frustrated two-leg spin ladder compound with a spin gap that can be closed with a magnetic field of approximately 20T to induce a soliton lattice. Time permitting, I will also discuss magnetization, magnetostriction and specific heat vs magnetic fields to 65 T used to obtain the anisotropic (H,T) phase diagram in BiCu2PO6 single crystal samples. Work at the NHMFL was supported by the National Science Foundation, the US Department of Energy Office of Basic Energy Science through the project ``Science at 100 Tesla,'' and the State of Florida.

  7. A 10 Kelvin 3 Tesla Magnet for Space Flight ADR Systems

    NASA Technical Reports Server (NTRS)

    Tuttle, Jim; Shirron, Peter; Canavan, Edgar; DiPirro, Michael; Riall, Sara; Pourrahimi, Shahin

    2003-01-01

    Many future space flight missions are expected to use adiabatic demagnetization refrigerators (ADRs) to reach detector operating temperatures well below one Kelvin. The goal is to operate each ADR with a mechanical cooler as its heat sink, thus avoiding the use of liquid cryogens. Although mechanical coolers are being developed to operate at temperatures of 6 Kelvin and below, there is a large efficiency cost associated with operating them at the bottom of their temperature range. For the multi-stage ADR system being developed at Goddard Space Flight Center, the goal is to operate with a 10 Kelvin mechanical cooler heat sink. With currently available paramagnetic materials, the highest temperature ADR stage in such a system will require a magnetic field of approximately three Tesla. Thus the goal is to develop a small, lightweight three Tesla superconducting magnet for operation at 10 Kelvin. It is important that this magnet have a low current/field ratio. Because traditional NbTi magnets do not operate safely above about six Kelvin, a magnet with a higher Tc is required. The primary focus has been on Nb3Sn magnets. Since standard Nb3Sn wire must be coated with thick insulation, wound on a magnet mandrel and then reacted, standard Nb,Sn magnets are quite heavy and require high currents Superconducting Systems developed a Nb3Sn wire which can be drawn down to small diameter, reacted, coated with thin insulation and then wound on a small diameter coil form. By using this smaller wire and operating closer to the wire s critical current, it should be possible to reduce the mass and operating current of 10 Kelvin magnets. Using this "react-then-wind" technology, Superconducting Systems has produced prototype 10 Kelvin magnets. This paper describes the development and testing of these magnets and discusses the outlook for including 10 Kelvin magnets on space-flight missions.

  8. Light storage and cavity supermodes in two coupled optomechanical cavities

    NASA Astrophysics Data System (ADS)

    He, Yong

    2016-12-01

    We theoretically investigate a hybrid optomechanical system including two coupled optomechanical cavities in the presence of two strong pump fields and a weak probe field. The photon-hopping coupling of the cavities gives rise to two cavity supermodes whose resonant frequencies can be obtained in the probe transmission spectrum. In a strong photon-hopping coupling regime, there is a large coupling rate between the probe field and one of the two cavity supermodes that is called a bright mode. The optomechanical couplings between the bright mode and two mechanical resonators can cause double optomechanically induced transparency (OMIT), which can be employed to both separately and simultaneously store two weak probe pulses with different central frequencies. We obtain the group delay (light storage time) of the probe field in the hybrid optomechanical system. The results suggest that compared with that of a single cavity optomechanical system, the maximum value of the storage time roughly quadrupled in a particular case. The physical origin of the results is discussed. The hybrid optomechanical system opens an avenue of light storage in cavity optomechanics.

  9. Geometry-invariant resonant cavities

    PubMed Central

    Liberal, I.; Mahmoud, A. M.; Engheta, N.

    2016-01-01

    Resonant cavities are one of the basic building blocks in various disciplines of science and technology, with numerous applications ranging from abstract theoretical modelling to everyday life devices. The eigenfrequencies of conventional cavities are a function of their geometry, and, thus, the size and shape of a resonant cavity is selected to operate at a specific frequency. Here we demonstrate theoretically the existence of geometry-invariant resonant cavities, that is, resonators whose eigenfrequencies are invariant with respect to geometrical deformations of their external boundaries. This effect is obtained by exploiting the unusual properties of zero-index metamaterials, such as epsilon-near-zero media, which enable decoupling of the temporal and spatial field variations in the lossless limit. This new class of resonators may inspire alternative design concepts, and it might lead to the first generation of deformable resonant devices. PMID:27010103

  10. CRAB Cavity in CERN SPS

    SciTech Connect

    Kim, H.J.; Sen, T.; /Fermilab

    2010-05-01

    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.

  11. Geometry-invariant resonant cavities

    NASA Astrophysics Data System (ADS)

    Liberal, I.; Mahmoud, A. M.; Engheta, N.

    2016-03-01

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

  12. [Radiotherapy for oral cavity cancers].

    PubMed

    Lapeyre, M; Biau, J; Racadot, S; Moreira, J F; Berger, L; Peiffert, D

    2016-09-01

    Intensity modulated radiation therapy (IMRT) and brachytherapy are standard techniques for the irradiation of oral cavity cancers. These techniques are detailed in terms of indication, preparation, delineation and selection of the volumes, dosimetry and patient positioning control.

  13. Active Control of Open Cavities

    NASA Technical Reports Server (NTRS)

    UKeiley, Lawrence

    2010-01-01

    Open loop edge blowing was demonstrated as an effective method for reducing the broad band and tonal components of the fluctuating surface pressure in open cavities. Closed loop has been successfully applied to low Mach number open cavities. Need to push actuators that are viable for closed loop control in bandwidth and output. Need a better understanding of the effects of control on the flow through detailed measurements so better actuation strategies can be developed.

  14. Cavity alignment using fringe scanning

    NASA Astrophysics Data System (ADS)

    Sinkunaite, Laura Paulina; Kawabe, Keita; Landry, Michael

    2017-01-01

    LIGO employs two 4-km long Fabry-Pérot arm cavities, which need to be aligned in order for an interferometer to be locked on a TEM00 mode. Once the cavity is locked, alignment signals can be derived from wave-front sensors which measure the TEM01 mode content. However, the alignment state is not always good enough for locking on TEM00. Even when this is the case, the alignment can be evaluated using a free swinging cavity, that shows flashes when higher-order modes become resonant. By moving test masses, small changes are made to the mirror orientation, and hence the TEM00 mode can be optimized iteratively. Currently, this is a manual procedure, and thus it is very time-consuming. Therefore, this project is aimed to study another possible way to lock the cavity on the TEM00 mode. Misalignment information can also be extracted from the power of the higher-order modes transmitted through the cavity. This talk will present an algorithm for this alternative and faster way to derive the alignment state of the arm cavities. Supported by APS FIP, NSF, and Caltech SFP.

  15. Fabrication of elliptical SRF cavities

    NASA Astrophysics Data System (ADS)

    Singer, W.

    2017-03-01

    The technological and metallurgical requirements of material for high-gradient 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 10 μg g-1. The hydrogen content should be kept below 2 μg g-1 to prevent degradation of the quality factor (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. Traditional and alternative cavity mechanical 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. The welding of half-cells is a delicate procedure, requiring intermediate cleaning steps and a careful choice of weld parameters to achieve full penetration of the joints. A challenge for a welded construction is the tight mechanical and electrical tolerances. These can be maintained by a combination of mechanical and radio-frequency measurements on half-cells and by careful tracking of weld shrinkage. The main aspects of quality assurance and quality management are mentioned. The experiences of 800 cavities produced for the European XFEL are presented. Another cavity fabrication approach is slicing discs from the ingot and producing cavities by deep drawing and electron beam welding. Accelerating gradients at the level of 35-45 MV m-1 can be achieved by applying electrochemical polishing treatment. The single-crystal option (grain boundary free) is discussed. It seems that in this case, high performance can be achieved by a simplified treatment procedure. Fabrication of the elliptical resonators from a seamless pipe as an alternative is briefly described. This technology has yielded good

  16. Normal Conducting RF Cavity for MICE

    SciTech Connect

    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.

  17. The ESS elliptical cavity cryomodules

    SciTech Connect

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

    2014-01-29

    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.

  18. The ESS spoke cavity cryomodules

    SciTech Connect

    Bousson, Sebastien; Duthil, Patxi; Reynet, Denis; Thermeau, Jean-Pierre

    2014-01-29

    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.

  19. Coupling of an overdriven cavity

    SciTech Connect

    Garbin, H D

    1993-11-01

    It is well known that when a nuclear test is conducted in a sufficiently large cavity, the resulting seismic signal is sharply reduced when compared to a normal tamped event. Cavity explosions are of interest in the seismic verification community because of this possibility of reducing the seismic energy generated which can lower signal amplitudes and make detection difficult. Reduced amplitudes would also lower seismic yield estimates which has implications in a Threshold Test Ban Treaty (TTBT). In the past several years, there have been a number of nuclear tests at NTS (Nevada Test Site) inside hemispherical cavities. Two such tests were MILL YARD and MISTY ECHO which had instrumentation at the surface and in the free-field. These two tests differ in one important aspect. MILL YARD was completely decoupled i.e., the cavity wall behaved in an elastic manner. It was estimated that MILL YARD`s ground motion was reduced by a factor of at least 70. In contrast, MISTY ECHO was detonated in a hemispherical cavity with the same dimensions as MILL YARD, but with a much larger device yield. This caused an inelastic behavior on the wall and the explosion was not fully decoupled.

  20. Modules for 6.0 Tesla, vertically separated, clustered or distributed lattices

    SciTech Connect

    Peggs, S.

    1985-10-01

    A total of four lattices have been designed for distributed and (3,3) clustered versions of the SSC, and are available in the SSC database, SSCDB. These lattices are constructed of the same four basic modules, which with only minor tuning can be re-organised to form many conceivable realistic geometries. One module is trivial, consisting of regular cells in a long main arc. The description of the other three modules is the central theme of this report. Potential improvements in both the modules and their implementation are also mentioned. The lattices, with the generic name VSDlbnn.DAT, are in MAD/standard input format in the [SSCDB.LATTICES] directory of the database. Lower case letters in the generic name represent variable characters, where {open_quotes}b{close_quotes} is either C or D, according to whether the lattice is (3,3) Clustered or Distributed, and where {open_quotes}nn{close_quotes} is 01 or 10, according to whether the collision beta is {beta}{sup *} = 1.0 or 10.0 metres, in luminosity or injection lattices. The general title {open_quotes}VS{close_quotes} stands for the Vertical Separation of the two beam lines, with a (total) separation in the main arcs of 0.70 metres, while the notation {open_quotes}Dl{close_quotes} reflects the regular cell dipoles of 6.0 Tesla ({open_quotes}D{close_quotes}), with a phase advance per cell of 60 degrees ({open_quotes}1{close_quotes}). The half cell length is 100 metres. It would be useful for lattice designers and users in the SSC design community to agree on some such lattice naming convention, even if the agreement is merely informal. Two criticisms of the above convention are first, that since the magnet selection for the SSC has fixed the dipole field to be close to 6.4 Tesla, the {open_quotes}D{close_quotes} definition of dipole strength is redundant, and second, that collision betas of less than 1.0 metre can not be handled unless three digits, {open_quotes}nnn{close_quotes}, are included.

  1. Magnetic resonance imaging investigation of the bone conduction implant – a pilot study at 1.5 Tesla

    PubMed Central

    Jansson, Karl-Johan Fredén; Håkansson, Bo; Reinfeldt, Sabine; Rigato, Cristina; Eeg-Olofsson, Måns

    2015-01-01

    Purpose The objective of this pilot study was to investigate if an active bone conduction implant (BCI) used in an ongoing clinical study withstands magnetic resonance imaging (MRI) of 1.5 Tesla. In particular, the MRI effects on maximum power output (MPO), total harmonic distortion (THD), and demagnetization were investigated. Implant activation and image artifacts were also evaluated. Methods and materials One implant was placed on the head of a test person at the position corresponding to the normal position of an implanted BCI and applied with a static pressure using a bandage and scanned in a 1.5 Tesla MRI camera. Scanning was performed both with and without the implant, in three orthogonal planes, and for one spin-echo and one gradient-echo pulse sequence. Implant functionality was verified in-between the scans using an audio processor programmed to generate a sequence of tones when attached to the implant. Objective verification was also carried out by measuring MPO and THD on a skull simulator as well as retention force, before and after MRI. Results It was found that the exposure of 1.5 Tesla MRI only had a minor effect on the MPO, ie, it decreased over all frequencies with an average of 1.1±2.1 dB. The THD remained unchanged above 300 Hz and was increased only at lower frequencies. The retention magnet was demagnetized by 5%. The maximum image artifacts reached a distance of 9 and 10 cm from the implant in the coronal plane for the spin-echo and the gradient-echo sequence, respectively. The test person reported no MRI induced sound from the implant. Conclusion This pilot study indicates that the present BCI may withstand 1.5 Tesla MRI with only minor effects on its performance. No MRI induced sound was reported, but the head image was highly distorted near the implant. PMID:26604836

  2. A SURVEY OF CORONAL CAVITY DENSITY PROFILES

    SciTech Connect

    Fuller, J.; Gibson, S. E.

    2009-08-01

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

  3. Sex hormone status in male rats after exposure to 50 Hz, 5 mTesla magnetic field.

    PubMed

    Mostafa, R M; Moustafa, Y M; Ali, F M; Shafik, A

    2006-01-01

    The question of whether extremely low frequency magnetic fields can affect biological system has attracted attention. The theoretical possibility of such an interaction is often questioned and the site of interaction is unknown. The influence of extremely low frequency magnetic field of 50 Hz, 5 mTesla on sex hormone status was studied. 60 male albino rats were divided into 6 groups and were continuously exposed to 50 Hz, 5 mTesla magnetic field generated by magnetic field chamber for periods of 1, 2 and 4 weeks. For each experimental point, sham treated group was used as a control. Assay of serum testosterone LH, FSH, and prolactin were performed. Serum testosterone showed no significant changes. FSH showed significant increase than sham exposed group after 1 week magnetic field exposure. LH showed significant increase than sham exposed group only after 4 weeks magnetic field exposure, while serum prolactin hormone level showed a significant increase in all magnetic field exposed groups than sham exposed animals. Exposure to 50 Hz, 5 mTesla magnetic field for periods of 1, 2 and 4 weeks has no effect on testosterone level, some changes on FSH and LH serum levels and increase in serum prolactin level.

  4. Is the Ellipsoid Formula the New Standard for 3-Tesla MRI Prostate Volume Calculation without Endorectal Coil?

    PubMed

    Haas, Matthias; Günzel, Karsten; Miller, Kurt; Hamm, Bernd; Cash, Hannes; Asbach, Patrick

    2017-01-01

    Prostate volume in multiparametric MRI (mpMRI) is of clinical importance. For 3-Tesla mpMRI without endorectal coil, there is no distinctive standard for volume calculation. We tested the accuracy of the ellipsoid formula with planimetric volume measurements as reference and investigated the correlation of gland volume and cancer detection rate on MRI/ultrasound (MRI/US) fusion-guided biopsy. One hundred forty-three patients with findings on 3-Tesla mpMRI suspicious of cancer and subsequent MRI/US fusion-guided targeted biopsy and additional systematic biopsy were analyzed. T2-weighted images were used for measuring the prostate diameters and for planimetric volume measurement by a segmentation software. Planimetric and calculated prostate volumes were compared with clinical data. The median prostate volume was 48.1 ml (interquartile range (IQR) 36.9-62.1 ml). Volume calculated by the ellipsoid formula showed a strong concordance with planimetric volume, with a tendency to underestimate prostate volume (median volume 43.1 ml (IQR 31.2-58.8 ml); r = 0.903, p < 0.001). There was a moderate, significant inverse correlation of prostate volume to a positive biopsy result (r = -0.24, p = 0.004). The ellipsoid formula gives sufficient approximation of prostate volume on 3-Tesla mpMRI without endorectal coil. It allows a fast, valid volume calculation in prostate MRI datasets.

  5. RRR Characteristics for SRF cavities

    NASA Astrophysics Data System (ADS)

    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.

  6. Cavity-controlled spectral singularity.

    PubMed

    Nireekshan Reddy, K; Dutta Gupta, S

    2014-08-01

    We study theoretically a parity-time (PT)-symmetric, saturable, balanced gain-loss system in a ring-cavity configuration. The saturable gain and loss are modeled by a two-level medium with or without population inversion. We show that the specifics of the spectral singularity can be fully controlled by the cavity and the atomic detuning parameters. The theory is based on the mean-field approximation, as in the standard theory of optical bistability. Further, in the linear regime we demonstrate the regularization of the singularity in detuned systems, while larger input power levels are shown to be adequate to limit the infinite growth in absence of detunings.

  7. Synchronization in an optomechanical cavity

    NASA Astrophysics Data System (ADS)

    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.

  8. Temperature optimization for superconducting cavities

    SciTech Connect

    Rode, Claus

    1999-06-01

    Since our previous analysis of optimized operating temperature of superconducting cavities in an accelerator a decade ago, significant additional information has been discovered about SRF cavities. The most significant is the Q0 (quality factor) shift across the Lambda line at higher gradients as a result of a slope in Q0 vs. Eacc above Lambda. This is a result of the changing heat conduction conditions. We discuss temperature optimizations as a function of gradient and frequency. The refrigeration hardware impacts and changes in cycle efficiency are presented.

  9. Experimental cavity pressure distributions at supersonic speeds

    NASA Technical Reports Server (NTRS)

    Stallings, Robert L., Jr.; Wilcox, Floyd J., Jr.

    1987-01-01

    An investigation was conducted to define pressure distributions for rectangular cavities over a range of free-stream Mach numbers and cavity dimensions. These pressure distributions together with schlieren photographs are used to define the critical values of cavity length-to-depth ratio that separate open type cavity flows from closed type cavity flows. For closed type cavity flow, the shear layer expands over the cavity leading edge and impinges on the cavity floor, whereas for open type cavity flow, the shear layer bridges the cavity. The tests were conducted by using a flat-plate model permitting the cavity length to be remotely varied from 0.5 to 12 in. Cavity depths and widths were varied from 0.5 to 2.5 in. The flat-plate boundary layer approaching the cavity was turbulent and had a thickness of approximately 0.2 in. at the cavity front face for the range of test Mach numbers from 1.5 to 2.86. Presented are a discussion of the results and a complete tabulation of the experimental data.

  10. Performance Analysis of Memory Transfers and GEMM Subroutines on NVIDIA Tesla GPU Cluster

    SciTech Connect

    Allada, Veerendra, Benjegerdes, Troy; Bode, Brett

    2009-08-31

    Commodity clusters augmented with application accelerators are evolving as competitive high performance computing systems. The Graphical Processing Unit (GPU) with a very high arithmetic density and performance per price ratio is a good platform for the scientific application acceleration. In addition to the interconnect bottlenecks among the cluster compute nodes, the cost of memory copies between the host and the GPU device have to be carefully amortized to improve the overall efficiency of the application. Scientific applications also rely on efficient implementation of the BAsic Linear Algebra Subroutines (BLAS), among which the General Matrix Multiply (GEMM) is considered as the workhorse subroutine. In this paper, they study the performance of the memory copies and GEMM subroutines that are critical to port the computational chemistry algorithms to the GPU clusters. To that end, a benchmark based on the NetPIPE framework is developed to evaluate the latency and bandwidth of the memory copies between the host and the GPU device. The performance of the single and double precision GEMM subroutines from the NVIDIA CUBLAS 2.0 library are studied. The results have been compared with that of the BLAS routines from the Intel Math Kernel Library (MKL) to understand the computational trade-offs. The test bed is a Intel Xeon cluster equipped with NVIDIA Tesla GPUs.

  11. MEG evaluation of pico-Tesla external TMS on multiple sclerosis patients.

    PubMed

    Anninos, P; Adamopoulos, A; Kotini, A; Tsagas, N

    2016-07-01

    Magnetoencephalographic (MEG) recordings of 10 multiple sclerosis (MS) patients (2 men, 8 women, mean 41.3±9.5 years, mean disease duration 12.7±7.2 years) were obtained using a whole-head 122 - channel MEG system in a magnetically shielded room of low magnetic noise. Our experimental design was double-blind in order to look for possible effect of external pico - Tesla Transcranial Magnetic Stimulation (pT-TMS). The external pT-TMS was applied on the MS patients with proper field characteristics (magnetic field amplitude: 1-7.5pT, frequency: the alpha-rhythm of the patient 8-13Hz) which were obtained prior to the application of pT-TMS. Each MS patient had two separate recording sessions consisting of 3 runs in between where were given real or sham pT-TMS. It was then tried to predict the real and sham stimulation sessions based on the changes in the mean peak frequency difference (MPFD) observed in the brain of the patients in the 2-7Hz frequency band. After unblinding it was found a significant effect of an increase of frequencies in the range of 2-7Hz across the subjects followed by an improvement and normalization of the MEG.

  12. New microwave beam position monitors for the TESLA test facility—FEL

    NASA Astrophysics Data System (ADS)

    Kamps, T.; Lorenz, R.

    1998-12-01

    Beam-based alignment is essential for the operation of the SASE-FEL at the TESLA Test Facility Linac. In order to ensure the overlap of the photon beam and the electron beam, the position of the electron beam has to be measured along the undulator beamline with a high resolution. Due to the severe space limitations, a new microwave concept is being considered. It is based on special ridged waveguides coupling by small slots to the magnetic field of the electron beam. The four waveguides and slots of each monitor were split into two symmetric pairs separated in beam direction. All waveguides are about 35 degrees apart in azimuth from the horizontal axis and will be fabricated using electro-discharge machining (EDM). Waveguide-to-coax adaptors were designed to couple the signal of each waveguide into a coaxial cable. The goal is to measure the averaged position of a bunch train in a narrowband receiver with a center frequency of 12 GHz. A prototype of this monitor was built and tested on a testbench, as well as at the CLIC Test Facility at CERN. The paper summarizes the concept, the design, and further improvements of the waveguide monitor.

  13. Constructing a 4-TESLA Large Thin Solenoid at the Limit of what can BE Safely Operated

    NASA Astrophysics Data System (ADS)

    Hervé, A.

    The 4-tesla, 6 m free bore CMS solenoid has been successfully tested, operated and mapped at CERN during the autumn of 2006 in a surface hall and fully recommissioned in the underground experimental area in the autumn of 2008. The conceptual design started in 1990, the R&D studies in 1993, and the construction was approved in 1997. At the time the main parameters of this project were considered beyond what was thought possible as, in particular, the total stored magnetic energy reaches 2.6 GJ for a specific magnetic energy density exceeding 11 kJ/kg of cold mass. During this period, the international design and construction team had to make several important technical choices, particularly mechanical ones, to maximize the chances of reaching the nominal induction of 4 T. These design choices are explained and critically reviewed in the light of what is presently known to determine if better solutions would be possible today for constructing a new large high-field thin solenoid for a future detector magnet.

  14. Constructing a 4-Tesla Large Thin Solenoid at the Limit of what can BE Safely Operated

    NASA Astrophysics Data System (ADS)

    Hervé, A.

    The 4-tesla, 6m free bore CMS solenoid has been successfully tested, operated and mapped at CERN during the autumn of 2006 in a surface hall and fully recommissioned in the underground experimental area in the autumn of 2008. The conceptual design started in 1990, the R&D studies in 1993, and the construction was approved in 1997. At the time the main parameters of this project were considered beyond what was thought possible as, in particular, the total stored magnetic energy reaches 2.6GJ for a specific magnetic energy density exceeding 11 kJ/kg of cold mass. During this period, the international design and construction team had to make several important technical choices, particularly mechanical ones, to maximize the chances of reaching the nominal induction of 4T. These design choices are explained and critically reviewed in the light of what is presently known to determine if better solutions would be possible today for constructing a new large high-field thin solenoid for a future detector magnet.

  15. Imaging islets labeled with magnetic nanoparticles at 1.5 Tesla.

    PubMed

    Tai, Joo Ho; Foster, Paula; Rosales, Alma; Feng, Biao; Hasilo, Craig; Martinez, Violetta; Ramadan, Soha; Snir, Jonatan; Melling, C W James; Dhanvantari, Savita; Rutt, Brian; White, David J G

    2006-11-01

    We have developed a magnetic resonance imaging (MRI) technique for imaging Feridex (superparamagnetic iron oxide [SPIO])-labeled islets of Langerhans using a standard clinical 1.5-Tesla (T) scanner and employing steady-state acquisition imaging sequence (3DFIESTA). Both porcine and rat islets were labeled with SPIO by a transfection technique using a combination of poly-l-lysine and electroporation. Electron microscopy demonstrated presence of SPIO particles within the individual islet cells, including beta-cells and particles trapped between cell membranes. Our labeling method produced a transfection rate of 860 pg to 3.4 ng iron per islet, dependent on the size of the islet. The labeling procedure did not disrupt either the function or viability of the islets. In vitro 3DFIESTA magnetic resonance images of single-labeled islets corresponded with their optical images. In vivo T2*-weighted scan using 1.5 T detected as few as 200 SPIO-labeled islets transplanted under rat kidney capsule, which correlated with immunohistochemistry of the transplant for insulin and iron. Ex vivo 3DFIESTA images of kidneys containing 200, 800 or 2,000 SPIO-labeled islet isografts showed good correlation between signal loss and increasing numbers of islets. These data provide evidence that islets can be labeled with SPIO and imaged using clinically available 1.5- T MRI.

  16. Tuning magnetic disorder in diluted magnetic semiconductors using high fields to 89 Tesla

    SciTech Connect

    Crooker, Scott A; Samarth, Nitin

    2008-01-01

    We describe recent and ongoing studies at the National High Magnetic Field Laboratory at Los Alamos using the new '100 Tesla Multi-Shot Magnet', which is presently delivering fields up to {approx}89 T during its commissioning. We discuss the first experiments performed in this magnet system, wherein the linewidth of low-temperature photoluminescence spectra was used to directly reveal the degree of magnetic alloy disorder 'seen' by excitons in single Zn{sub 0.80}Cd{sub 0.22}Mn{sub 0.08}Se quantum wells. The magnetic potential landscape in II-VI diluted magnetic semiconductors (DMS) is typically smoothed when the embedded Mn{sup 2+} spins align in an applied field. However, an important (but heretofore untested) prediction of current models of compositional disorder is that magnetic alloy fluctuations in many DMS compounds should increase again in very large magnetic fields approaching 100 T. We observed precisely this increase above {approx}70 T, in agreement with a simple model of magnetic alloy disorder.

  17. An inverted-microstrip resonator for human head proton MR imaging at 7 tesla.

    PubMed

    Zhang, Xiaoliang; Ugurbil, Kamil; Sainati, Robert; Chen, Wei

    2005-03-01

    As an extension of the previously developed microstrip transmission line (MTL) RF coil design, a high-frequency RF volume coil using multiple inverted MTL (iMTL) resonators for human head imaging at high magnetic field strength of 7 tesla (T) is reported. Compared to conventional MTL resonators, iMTL resonators can operate at higher frequency with lower losses and, thus, are suitable for designs of high-frequency RF volume coils with large coil size for human MR imaging and spectroscopy at high fields. An approach using capacitive terminations was analyzed and applied to the design of the iMTL volume coil for improving RF field homogeneity and broadening frequency-tuning range. A performance-comparison study was conducted between the prototype iMTL volume coil and a custom-built TEM volume coil at 7 T. The iMTL volume coil presents a comparable SNR and intrinsic B1 homogeneity to the TEM volume coil. Phantom and the human head images acquired using the iMTL volume coil are also presented. The proposed iMTL volume coil provides an efficient and alternative solution to design high-frequency and large-size volume coils for human MR applications at very high fields.

  18. Human brain diffusion tensor imaging at submillimeter isotropic resolution on a 3Tesla clinical MRI scanner.

    PubMed

    Chang, Hing-Chiu; Sundman, Mark; Petit, Laurent; Guhaniyogi, Shayan; Chu, Mei-Lan; Petty, Christopher; Song, Allen W; Chen, Nan-kuei

    2015-09-01

    The advantages of high-resolution diffusion tensor imaging (DTI) have been demonstrated in a recent post-mortem human brain study (Miller et al., NeuroImage 2011;57(1):167-181), showing that white matter fiber tracts can be much more accurately detected in data at a submillimeter isotropic resolution. To our knowledge, in vivo human brain DTI at a submillimeter isotropic resolution has not been routinely achieved yet because of the difficulty in simultaneously achieving high resolution and high signal-to-noise ratio (SNR) in DTI scans. Here we report a 3D multi-slab interleaved EPI acquisition integrated with multiplexed sensitivity encoded (MUSE) reconstruction, to achieve high-quality, high-SNR and submillimeter isotropic resolution (0.85×0.85×0.85mm(3)) in vivo human brain DTI on a 3Tesla clinical MRI scanner. In agreement with the previously reported post-mortem human brain DTI study, our in vivo data show that the structural connectivity networks of human brains can be mapped more accurately and completely with high-resolution DTI as compared with conventional DTI (e.g., 2×2×2mm(3)).

  19. 21 Tesla Fourier Transform Ion Cyclotron Resonance Mass Spectrometer Greatly Expands Mass Spectrometry Toolbox

    NASA Astrophysics Data System (ADS)

    Shaw, Jared B.; Lin, Tzu-Yung; Leach, Franklin E.; Tolmachev, Aleksey V.; Tolić, Nikola; Robinson, Errol W.; Koppenaal, David W.; Paša-Tolić, Ljiljana

    2016-12-01

    We provide the initial performance evaluation of a 21 Tesla Fourier transform ion cyclotron resonance mass spectrometer operating at the Environmental Molecular Sciences Laboratory at the Pacific Northwest National Laboratory. The spectrometer constructed for the 21T system employs a commercial dual linear ion trap mass spectrometer coupled to a FTICR spectrometer designed and built in-house. Performance gains from moving to higher magnetic field strength are exemplified by the measurement of peptide isotopic fine structure, complex natural organic matter mixtures, and large proteins. Accurate determination of isotopic fine structure was demonstrated for doubly charged Substance P with minimal spectral averaging, and 8158 molecular formulas assigned to Suwannee River Fulvic Acid standard with root-mean-square (RMS) error of 10 ppb. We also demonstrated superior performance for intact proteins; namely, broadband isotopic resolution of the entire charge state distribution of apo-transferrin (78 kDa) and facile isotopic resolution of monoclonal antibody under a variety of acquisition parameters (e.g., 6 s time-domains with absorption mode processing yielded resolution of approximately 1 M at m/z = 2700).

  20. 7 Tesla fMRI Reveals Systematic Functional Organization for Binocular Disparity in Dorsal Visual Cortex

    PubMed Central

    Goncalves, Nuno R.; Ban, Hiroshi; Sánchez-Panchuelo, Rosa M.; Francis, Susan T.; Schluppeck, Denis

    2015-01-01

    The binocular disparity between the views of the world registered by the left and right eyes provides a powerful signal about the depth structure of the environment. Despite increasing knowledge of the cortical areas that process disparity from animal models, comparatively little is known about the local architecture of stereoscopic processing in the human brain. Here, we take advantage of the high spatial specificity and image contrast offered by 7 tesla fMRI to test for systematic organization of disparity representations in the human brain. Participants viewed random dot stereogram stimuli depicting different depth positions while we recorded fMRI responses from dorsomedial visual cortex. We repeated measurements across three separate imaging sessions. Using a series of computational modeling approaches, we report three main advances in understanding disparity organization in the human brain. First, we show that disparity preferences are clustered and that this organization persists across imaging sessions, particularly in area V3A. Second, we observe differences between the local distribution of voxel responses in early and dorsomedial visual areas, suggesting different cortical organization. Third, using modeling of voxel responses, we show that higher dorsal areas (V3A, V3B/KO) have properties that are characteristic of human depth judgments: a simple model that uses tuning parameters estimated from fMRI data captures known variations in human psychophysical performance. Together, these findings indicate that human dorsal visual cortex contains selective cortical structures for disparity that may support the neural computations that underlie depth perception. PMID:25698743

  1. A Tesla-pulse forming line-plasma opening switch pulsed power generator

    NASA Astrophysics Data System (ADS)

    Novac, B. M.; Kumar, R.; Smith, I. R.

    2010-10-01

    A pulsed power generator based on a high-voltage Tesla transformer which charges a 3.85 Ω/55 ns water-filled pulse forming line to 300 kV has been developed at Loughborough University as a training tool for pulsed power students. The generator uses all forms of insulation specific to pulsed power technology, liquid (oil and water), gas (SF6), and magnetic insulation in vacuum, and a number of fast voltage and current sensors are implemented for diagnostic purposes. A miniature (centimeter-size) plasma opening switch has recently been coupled to the output of the pulse forming line, with the overall system comprising the first phase of a program aimed at the development of a novel repetitive, table-top generator capable of producing 15 GW pulses for high power microwave loads. Technical details of all the generator components and the main experimental results obtained during the program and demonstrations of their performance are presented in the paper, together with a description of the various diagnostic tools involved. In particular, it is shown that the miniature plasma opening switch is capable of reducing the rise time of the input current while significantly increasing the load power. Future plans are outlined in the conclusions.

  2. Feasibility of MHD submarine propulsion. Phase II, MHD propulsion: Testing in a two Tesla test facility

    SciTech Connect

    Doss, E.D.; Sikes, W.C.

    1992-09-01

    This report describes the work performed during Phase 1 and Phase 2 of the collaborative research program established between Argonne National Laboratory (ANL) and Newport News Shipbuilding and Dry Dock Company (NNS). Phase I of the program focused on the development of computer models for Magnetohydrodynamic (MHD) propulsion. Phase 2 focused on the experimental validation of the thruster performance models and the identification, through testing, of any phenomena which may impact the attractiveness of this propulsion system for shipboard applications. The report discusses in detail the work performed in Phase 2 of the program. In Phase 2, a two Tesla test facility was designed, built, and operated. The facility test loop, its components, and their design are presented. The test matrix and its rationale are discussed. Representative experimental results of the test program are presented, and are compared to computer model predictions. In general, the results of the tests and their comparison with the predictions indicate that thephenomena affecting the performance of MHD seawater thrusters are well understood and can be accurately predicted with the developed thruster computer models.

  3. An efficient tensor transpose algorithm for multicore CPU, Intel Xeon Phi, and NVidia Tesla GPU

    SciTech Connect

    Lyakh, Dmitry I.

    2015-01-05

    An efficient parallel tensor transpose algorithm is suggested for shared-memory computing units, namely, multicore CPU, Intel Xeon Phi, and NVidia GPU. The algorithm operates on dense tensors (multidimensional arrays) and is based on the optimization of cache utilization on x86 CPU and the use of shared memory on NVidia GPU. From the applied side, the ultimate goal is to minimize the overhead encountered in the transformation of tensor contractions into matrix multiplications in computer implementations of advanced methods of quantum many-body theory (e.g., in electronic structure theory and nuclear physics). A particular accent is made on higher-dimensional tensors that typically appear in the so-called multireference correlated methods of electronic structure theory. Depending on tensor dimensionality, the presented optimized algorithms can achieve an order of magnitude speedup on x86 CPUs and 2-3 times speedup on NVidia Tesla K20X GPU with respect to the na ve scattering algorithm (no memory access optimization). Furthermore, the tensor transpose routines developed in this work have been incorporated into a general-purpose tensor algebra library (TAL-SH).

  4. An efficient tensor transpose algorithm for multicore CPU, Intel Xeon Phi, and NVidia Tesla GPU

    DOE PAGES

    Lyakh, Dmitry I.

    2015-01-05

    An efficient parallel tensor transpose algorithm is suggested for shared-memory computing units, namely, multicore CPU, Intel Xeon Phi, and NVidia GPU. The algorithm operates on dense tensors (multidimensional arrays) and is based on the optimization of cache utilization on x86 CPU and the use of shared memory on NVidia GPU. From the applied side, the ultimate goal is to minimize the overhead encountered in the transformation of tensor contractions into matrix multiplications in computer implementations of advanced methods of quantum many-body theory (e.g., in electronic structure theory and nuclear physics). A particular accent is made on higher-dimensional tensors that typicallymore » appear in the so-called multireference correlated methods of electronic structure theory. Depending on tensor dimensionality, the presented optimized algorithms can achieve an order of magnitude speedup on x86 CPUs and 2-3 times speedup on NVidia Tesla K20X GPU with respect to the na ve scattering algorithm (no memory access optimization). Furthermore, the tensor transpose routines developed in this work have been incorporated into a general-purpose tensor algebra library (TAL-SH).« less

  5. A combined study of MEG and pico-Tesla TMS on children with autism disorder.

    PubMed

    Anninos, Photios; Chatzimichael, Athanasios; Adamopoulos, Adam; Kotini, Athanasia; Tsagas, Nicolaos

    2016-12-01

    Magnetoencephalographic (MEG) recordings from the brain of 10 children with autism (6 boys and 4 girls, with ages range from 5-12 years, mean[Formula: see text][Formula: see text][Formula: see text]SD: 8.3[Formula: see text][Formula: see text][Formula: see text]2.1) were obtained using a whole-head 122-channel MEG system in a magnetically shielded room of low magnetic noise. A double-blind experimental design was used in order to look for possible effect of external pico-Tesla Transcranial Magnetic Stimulation (pT-TMS). The pT-TMS was applied on the brain of the autistic children with proper field characteristics (magnetic field amplitude: 1-7.5[Formula: see text]pT, frequency: the alpha - rhythm of the patient 8-13[Formula: see text]Hz). After unblinding it was found a significant effect of an increase of frequencies in the range of 2-7[Formula: see text]Hz across the subjects followed by an improvement and normalization of their MEG recordings. The statistical analysis of our results showed a statistical significance at 6 out of 10 patients (60%). It is also observed an increase of alpha activity in autistic children at the end of one month after pT-TMS treatment at home. In conclusion, the application of pT-TMS has the prospective to be a noninvasive, safe and important modality in the management of autism children.

  6. Dynamic Multi-Coil Shimming of the Human Brain at 7 Tesla

    PubMed Central

    Juchem, Christoph; Nixon, Terence W.; McIntyre, Scott; Boer, Vincent O.; Rothman, Douglas L.; de Graaf, Robin A.

    2011-01-01

    High quality magnetic field homogenization of the human brain (i.e. shimming) for MR imaging and spectroscopy is a demanding task. The susceptibility differences between air and tissue are a longstanding problem as they induce complex field distortions in the prefrontal cortex and the temporal lobes. To date, the theoretical gains of high field MR have only been realized partially in the human brain due to limited magnetic field homogeneity. A novel shimming technique for the human brain is presented that is based on the combination of non-orthogonal basis fields from 48 individual, circular coils. Custom-built amplifier electronics enabled the dynamic application of the multi-coil shim fields in a slice-specific fashion. Dynamic multi-coil (DMC) shimming is shown to eliminate most of the magnetic field inhomogeneity apparent in the human brain at 7 Tesla and provided improved performance compared to state-of-the-art dynamic shim updating with zero through third order spherical harmonic functions. The novel technique paves the way for high field MR applications of the human brain for which excellent magnetic field homogeneity is a prerequisite. PMID:21824794

  7. The Safety of MR Conditional Cochlear Implant at 1.5 Tesla Magnetic Resonance Imaging System.

    PubMed

    Takahashi, Daisuke; Ogura, Akio; Hayashi, Norio; Seino, Shinya; Kawai, Ryosuke; Matsuda, Tsuyoshi; Doi, Tsukasa; Tsuchihashi, Toshio

    2016-08-01

    In magnetic resonance imaging (MRI) examination of the patients with the cochlear implant, only limited data have a mention for safety information in the instruction manual supplied by the manufacturers. Therefore, imaging operators require more detailed safety information for implant device. We conducted detailed examination about displacement force, torque, and demagnetizing of the cochlear implant magnet based on American Society for Testing and Materials (ASTM) standard using the PULSAR and CONCERTO (MED-EL) with 1.5 tesla MRI system. As a result, the displacement force and the torque of the implant magnet were less than the numerical values descried in the manual. Therefore, these have almost no effect on the body under the condition described in a manual. In addition, the demagnetizing factor of the cochlear implant magnet occurred by a change magnetic field. The demagnetization depended on the direction of a line of magnetic force of the static magnetic field and the implant magnet. In conclusion, the operator must warn the position of the patients on inducing in the magnet room.

  8. Studies on a VUV free electron laser at the TESLA Test Facility at DESY

    SciTech Connect

    Rossbach, J.

    1995-12-31

    The TESLA Test Facility (TTF) currently under construction at DESY is a test-bed for acceleration sections of a high-gradient, high efficiency superconducting linear collider. Due to ist unrivaled ability to sustain high beam quality during acceleration, a superconducting rf linac is considered the optimum choice to drive a Free Electron Laser (FEL). We aim at a photon wavelength of {lambda} = 6 manometer utilizing the TTF after is has been extended to 1 GeV beam energy. Due to lack of mirrors and seed-lasers in this wavelength regime, a single pass FEL and Self-Amplified-Spontaneous-Emission (SASE) is considered. A first test is foreseen at a larger photon wavelength. The overall design as well as both electron and photon beam properties will be discussed. To reach the desired photon wavelength, the main components that have to be added to the TTF are: (a) a low emittance rf gun including space charge compensation (b) a two stage bunch compressor increasing the peak bunch current from 100 A up to 2500 A (c) four more accelerating modules to achieve 1 GeV beam energy (d) a 25 m long undulator (period length 27 mm, peak field 0.5 T) The average brillance will be larger than 1-10{sup 22}photons/s/mm{sup 2}/mrad{sup 2}/0.1%. Each 800 {mu}s long pulse will contain up to 7200 equidistant bunches. The repetition frequency of the linac is 10 Hz.

  9. Two-Slotted Surface Coil Array for Magnetic Resonance Imaging at 4 Tesla

    SciTech Connect

    Solis, S. E.; Hernandez, J. A.; Rodriguez, A. O.; Tomasi, D.

    2008-08-11

    Arrays of antennas have been widely accepted for magnetic resonance imaging applications due to their high signal-to-noise ratio (SNR) over large volumes of interest. A new surface coil based on the magnetron tube and called slotted surface coil, has been recently introduced by our group. This coil design experimentally demonstrated a significant improvement over the circular-shaped coil when used in the receive-only mode. The slotted coils formed a two-sheet structure with a 90 deg. separation and each coil had 6 circular slots. Numerical simulations were performed using the finite element method for this coil design to study the behaviour of the array magnetic field. Then, we developed a two-coil array for brain magnetic resonance imaging to be operated at the resonant frequency of 170 MHz in the transceiver mode. Phantom images were acquired with our coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. Numerical simulations demonstrated that electromagnetic interaction between the coil elements is negligible, and that the magnetic field showed a good uniformity. In vitro images showed the feasibility of this coil array for standard pulses for high field magnetic resonance imaging.

  10. Computational fluid dynamics design and analysis of a passively suspended Tesla pump left ventricular assist device.

    PubMed

    Medvitz, Richard B; Boger, David A; Izraelev, Valentin; Rosenberg, Gerson; Paterson, Eric G

    2011-05-01

    This article summarizes the use of computational fluid dynamics (CFD) to design a novel suspended Tesla left ventricular assist device. Several design variants were analyzed to study the parameters affecting device performance. CFD was performed at pump speeds of 6500, 6750, and 7000 rpm and at flow rates varying from 3 to 7 liters per minute (LPM). The CFD showed that shortening the plates nearest the pump inlet reduced the separations formed beneath the upper plate leading edges and provided a more uniform flow distribution through the rotor gaps, both of which positively affected the device hydrodynamic performance. The final pump design was found to produce a head rise of 77 mm Hg with a hydraulic efficiency of 16% at the design conditions of 6 LPM through flow and a 6750 rpm rotation rate. To assess the device hemodynamics the strain rate fields were evaluated. The wall shear stresses demonstrated that the pump wall shear stresses were likely adequate to inhibit thrombus deposition. Finally, an integrated field hemolysis model was applied to the CFD results to assess the effects of design variation and operating conditions on the device hemolytic performance.

  11. Mapping quantal touch using 7 Tesla functional magnetic resonance imaging and single-unit intraneural microstimulation

    PubMed Central

    Sanchez Panchuelo, Rosa Maria; Ackerley, Rochelle; Glover, Paul M; Bowtell, Richard W; Wessberg, Johan

    2016-01-01

    Using ultra-high field 7 Tesla (7T) functional magnetic resonance imaging (fMRI), we map the cortical and perceptual responses elicited by intraneural microstimulation (INMS) of single mechanoreceptive afferent units in the median nerve, in humans. Activations are compared to those produced by applying vibrotactile stimulation to the unit’s receptive field, and unit-type perceptual reports are analyzed. We show that INMS and vibrotactile stimulation engage overlapping areas within the topographically appropriate digit representation in the primary somatosensory cortex. Additional brain regions in bilateral secondary somatosensory cortex, premotor cortex, primary motor cortex, insula and posterior parietal cortex, as well as in contralateral prefrontal cortex are also shown to be activated in response to INMS. The combination of INMS and 7T fMRI opens up an unprecedented opportunity to bridge the gap between first-order mechanoreceptive afferent input codes and their spatial, dynamic and perceptual representations in human cortex. DOI: http://dx.doi.org/10.7554/eLife.12812.001 PMID:27154626

  12. Practical Methods for Improving B1+ Homogeneity in 3 Tesla Breast Imaging

    PubMed Central

    Winkler, Simone A.; Rutt, Brian K.

    2016-01-01

    Purpose To improve image contrast and B1+ field homogeneity in 3 Tesla (T) breast MR. Materials and Methods Two practical B1+ shimming methods for 3T breast MR are presented; low-cost passive shimming using local pads of high dielectric permittivity (εr from 0 to 100), and two-channel radiofrequency (RF) shimming (adjusting Q-I amplitude ratios and phase differences of 0 to −4 dB and 90 to 45 degrees), as well as a combination of both methods. The technique has been studied both in simulation using a numerical body model with added mammary tissue and in vivo in six subjects. Results Large improvements are observed with both methods, leading to a decrease in left–right B1+ asymmetry ratio of 1.24 to 1.00 (simulation) and from 1.26 to 1.01 (in vivo). RF safety was not adversely affected. Conclusion Both RF shimming and dielectric shimming were shown to improve inhomogeneity in the B1+ field in 3T breast MR. PMID:24723508

  13. Electromagnetic perspective on the operation of RF coils at 1.5-11.7 Tesla.

    PubMed

    Ibrahim, Tamer S; Mitchell, Chad; Schmalbrock, Petra; Lee, Robert; Chakeres, Donald W

    2005-09-01

    In this work experimental and numerical studies of the MR signal were performed at frequencies ranging from 64 MHz to 485 MHz, utilizing three different MRI coils: a single-strut transverse electromagnetic (TEM)-based coil, a TEM resonator, and a high-pass birdcage coil. The experimental analyses were conducted using 1.5 and 8 Tesla whole-body systems and volume RF head coils. The simulation data were obtained utilizing an in-house-developed finite difference time domain (FDTD) model. Pertinent data from the numerical and experimental setups were compared, and a remarkable agreement between the two methods was found that clearly demonstrates the effectiveness of the FDTD method when it is applied rigorously. The numerical and experimental studies demonstrate the complexity of the electromagnetic (EM) fields and their role in the MR signal. These studies also reveal unique similarities and differences between the transmit and receive field distributions at various field strengths. Finally, for ultra high-field operations, it was demonstrated mathematically, numerically, and experimentally that highly asymmetric inhomogeneous images can be acquired even for linear excitation, symmetrical load geometries, and symmetrical load positioning within the coil.

  14. Comparison of 3 and 7 Tesla Magnetic Resonance Imaging of Obstructive Hydrocephalus Caused by Tectal Glioma

    PubMed Central

    Moon, Hyeong Cheol; Baek, Hyeon-Man

    2016-01-01

    Obstructive hydrocephalus caused by tectal glioma, which relived by neuroendoscopy, have been described using 3.0 Tesla magnetic resonance imaging (3T MRI) so far, we present the results obtained from 3T and 7T MRI in this patient. A 21-year-old woman presented at our hospital with gait disturbance, hormonal insufficiency, and urinary incontinence that began prior to 6 years of age. 3.0T MRI revealed a non-enhancing tectal mass along with obstructive hydrocephalus. The mass measured approximately 1.1×1.0×1.2 cm. An endoscopic third ventriculostomy was performed to relieve the hydrocephalus. We compared hydrocephalus and cerebrospinal fluid (CSF) flow findings from 3T and 7T MRI, both preoperative and postoperative at 1, 6 months. Intraventricular CSF voiding on T2-weighted images obtained with 7T MRI showed greater fluid inversion than those obtained with 3T MRI. This study shows that 7T brain MRI can provide detailed information on hydrocephalus caused by tectal glioma. Further studies are needed to develop refined 7T MRI protocols for better images of hydrocephalus. PMID:27867929

  15. Examining the McGurk illusion using high-field 7 Tesla functional MRI

    PubMed Central

    Szycik, Gregor R.; Stadler, Jörg; Tempelmann, Claus; Münte, Thomas F.

    2012-01-01

    In natural communication speech perception is profoundly influenced by observable mouth movements. The additional visual information can greatly facilitate intelligibility but incongruent visual information may also lead to novel percepts that neither match the auditory nor the visual information as evidenced by the McGurk effect. Recent models of audiovisual (AV) speech perception accentuate the role of speech motor areas and the integrative brain sites in the vicinity of the superior temporal sulcus (STS) for speech perception. In this event-related 7 Tesla fMRI study we used three naturally spoken syllable pairs with matching AV information and one syllable pair designed to elicit the McGurk illusion. The data analysis focused on brain sites involved in processing and fusing of AV speech and engaged in the analysis of auditory and visual differences within AV presented speech. Successful fusion of AV speech is related to activity within the STS of both hemispheres. Our data supports and extends the audio-visual-motor model of speech perception by dissociating areas involved in perceptual fusion from areas more generally related to the processing of AV incongruence. PMID:22529797

  16. Effect of 1. 5 tesla nuclear magnetic resonance imaging scanner on implanted permanent pacemakers

    SciTech Connect

    Hayes, D.L.; Holmes, D.R. Jr.; Gray, J.E.

    1987-10-01

    Patients with a permanent pacemaker are currently restricted from diagnostic nuclear magnetic resonance (NMR) imaging because of potential adverse effects on the pacemaker by the magnet. Previous work has shown that NMR imaging will result in asynchronous pacing of the pulse generator within a given distance of the magnet. The radiofrequency signal generated by the system may also result in rapid cardiac pacing, which may have deleterious effects. This study utilized a 1.5 tesla unit in an in vivo laboratory animal to evaluate the unit's effects on eight different pulse generators from two manufacturers. All pacemakers functioned in an asynchronous mode when placed within a certain distance of the magnet. In addition, transient reed switch inhibition was observed. Seven of the eight pulse generators paced rapidly when exposed to the radiofrequency signal and there was a dramatic decrease in arterial blood pressure. Whether effective rapid cardiac pacing would occur could not be predicted before exposure to the magnetic resonance unit. Nuclear magnetic resonance imaging with high magnetic fields in patients with a pacemaker should continue to be avoided until the mechanism of the rapid cardiac pacing can be further delineated and either predicted or prevented.

  17. CFD Design and Analysis of a Passively Suspended Tesla Pump Left Ventricular Assist Device

    PubMed Central

    Medvitz, Richard B.; Boger, David A.; Izraelev, Valentin; Rosenberg, Gerson; Paterson, Eric G.

    2012-01-01

    This paper summarizes the use of computational fluid dynamics (CFD) to design a novelly suspended Tesla LVAD. Several design variants were analyzed to study the parameters affecting device performance. CFD was performed at pump speeds of 6500, 6750 and 7000 RPM and at flow rates varying from 3 to 7 liter-per-minute (LPM). The CFD showed that shortening the plates nearest the pump inlet reduced the separations formed beneath the upper plate leading edges and provided a more uniform flow distribution through the rotor gaps, both of which positively affected the device hydrodynamic performance. The final pump design was found to produce a head rise of 77 mmHg with a hydraulic efficiency of 16% at the design conditions of 6 LPM throughflow and a 6750 RPM rotation rate. To assess the device hemodynamics the strain rate fields were evaluated. The wall shear stresses demonstrated that the pump wall shear stresses were likely adequate to inhibit thrombus deposition. Finally, an integrated field hemolysis model was applied to the CFD results to assess the effects of design variation and operating conditions on the device hemolytic performance. PMID:21595722

  18. 21 Tesla Fourier Transform Ion Cyclotron Resonance Mass Spectrometer Greatly Expands Mass Spectrometry Toolbox

    SciTech Connect

    Shaw, Jared B.; Lin, Tzu-Yung; Leach, Franklin E.; Tolmachev, Aleksey V.; Tolić, Nikola; Robinson, Errol W.; Koppenaal, David W.; Paša-Tolić, Ljiljana

    2016-10-12

    We provide the initial performance evaluation of a 21 Tesla Fourier transform ion cyclotron resonance mass spectrometer operating at the Environmental Molecular Sciences Laboratory at Pacific Northwest National Laboratory. The spectrometer constructed for the 21T system employs a commercial dual linear ion trap mass spectrometer coupled to a FTICR spectrometer designed and built in-house. Performance gains from moving to higher magnetic field strength are exemplified by the measurement of peptide isotopic fine structure, complex natural organic matter mixtures, and large proteins. Accurate determination of isotopic fine structure was demonstrated for doubly charged substance P with minimal spectral averaging, and 8,158 molecular formulas assigned to Suwannee River Fulvic Acid standard with RMS error of 10 ppb. We also demonstrated superior performance for intact proteins; namely, broadband isotopic resolution of the entire charge state distribution of apotransferrin (78 kDa) and facile isotopic resolution of monoclonal antibody under a variety of acquisition parameters (e.g. 6 s time-domains with absorption mode processing yielded resolution of approximately 1M at m/z =2,700).

  19. Partial epilepsy: A pictorial review of 3 TESLA magnetic resonance imaging features

    PubMed Central

    Abud, Lucas Giansante; Thivard, Lionel; Abud, Thiago Giansante; Nakiri, Guilherme Seizem; dos Santos, Antonio Carlos; Dormont, Didier

    2015-01-01

    Epilepsy is a disease with serious consequences for patients and society. In many cases seizures are sufficiently disabling to justify surgical evaluation. In this context, Magnetic Resonance Imaging (MRI) is one of the most valuable tools for the preoperative localization of epileptogenic foci. Because these lesions show a large variety of presentations (including subtle imaging characteristics), their analysis requires careful and systematic interpretation of MRI data. Several studies have shown that 3 Tesla (T) MRI provides a better image quality than 1.5 T MRI regarding the detection and characterization of structural lesions, indicating that high-field-strength imaging should be considered for patients with intractable epilepsy who might benefit from surgery. Likewise, advanced MRI postprocessing and quantitative analysis techniques such as thickness and volume measurements of cortical gray matter have emerged and in the near future, these techniques will routinely enable more precise evaluations of such patients. Finally, the familiarity with radiologic findings of the potential epileptogenic substrates in association with combined use of higher field strengths (3 T, 7 T, and greater) and new quantitative analytical post-processing techniques will lead to improvements regarding the clinical imaging of these patients. We present a pictorial review of the major pathologies related to partial epilepsy, highlighting the key findings of 3 T MRI. PMID:26375569

  20. 7 tesla FMRI reveals systematic functional organization for binocular disparity in dorsal visual cortex.

    PubMed

    Goncalves, Nuno R; Ban, Hiroshi; Sánchez-Panchuelo, Rosa M; Francis, Susan T; Schluppeck, Denis; Welchman, Andrew E

    2015-02-18

    The binocular disparity between the views of the world registered by the left and right eyes provides a powerful signal about the depth structure of the environment. Despite increasing knowledge of the cortical areas that process disparity from animal models, comparatively little is known about the local architecture of stereoscopic processing in the human brain. Here, we take advantage of the high spatial specificity and image contrast offered by 7 tesla fMRI to test for systematic organization of disparity representations in the human brain. Participants viewed random dot stereogram stimuli depicting different depth positions while we recorded fMRI responses from dorsomedial visual cortex. We repeated measurements across three separate imaging sessions. Using a series of computational modeling approaches, we report three main advances in understanding disparity organization in the human brain. First, we show that disparity preferences are clustered and that this organization persists across imaging sessions, particularly in area V3A. Second, we observe differences between the local distribution of voxel responses in early and dorsomedial visual areas, suggesting different cortical organization. Third, using modeling of voxel responses, we show that higher dorsal areas (V3A, V3B/KO) have properties that are characteristic of human depth judgments: a simple model that uses tuning parameters estimated from fMRI data captures known variations in human psychophysical performance. Together, these findings indicate that human dorsal visual cortex contains selective cortical structures for disparity that may support the neural computations that underlie depth perception.

  1. Measurement and evaluation of the acoustic noise of a 3 Tesla MR scanner.

    PubMed

    Hattori, Yoko; Fukatsu, Hiroshi; Ishigaki, Takeo

    2007-01-01

    We measured the sound level and frequencies of the acoustic noise generated by a 3 Tesla (T) MR scanner, and investigated the subjective sound level for 30 healthy volunteers with either earplugs, headphones or both. The sound level of 3T was found to be higher than that of 1.5T in all sequences. The peak sound pressure level of 3T ranged from 125.7 dB for MR angiography to 130.7 dB for single shot EPI on the linear scale. The equivalent noise level was from 110.0 dB for FLAIR to 115.8 dB for T1-IR on the A-weighted scale, which exceeded 99 dB, the level regulated by the International Electrotechnical Commission (IEC). The study of the subjective sound level showed that the effect of noise reduction was not significantly different between earplugs and headphones. However, the use of both devices could reduce the subjective sound level significantly better than either one alone (P < 0.01). Thus we propose wearing both devices for ear-protection during 3T examinations.

  2. Pressurized H2 rf Cavities in Ionizing Beams and Magnetic Fields

    SciTech Connect

    Chung, M.; Collura, M. G.; Flanagan, G.; Freemire, B.; Hanlet, P. M.; Jana, M. R.; Johnson, R. P.; Kaplan, D. M.; Leonova, M.; Moretti, A.; Popovic, M.; Schwarz, T.; Tollestrup, A.; Torun, Y.; Yonehara, K.

    2013-10-01

    A major technological challenge in building a muon cooling channel is operating RF cavities in multi-tesla external magnetic fields. We report the first experimental characterization of a high pressure gas-filled 805 MHz RF cavity for use with intense ionizing beams and strong external magnetic fields. RF power consumption by beam-induced plasma was investigated with hydrogen and deuterium gases with pressures between 20 and 100 atm and peak RF gradients between 5 and 50 MV/m. The energy absorption per ion pair-RF cycle ranges from 10-18 to 10-16 J. The low pressure case agrees well with an analytical model based on electron and ion mobilities. Varying concentrations of oxygen gas were investigated to remove free electrons from the cavity and reduce the RF power consumption. Measurements of the electron attachment time to oxygen and rate of ion-ion recombination were also made. Additionally, we demonstrate the operation of the gas-filled RF cavity in a solenoidal field of up to 3 T, finding no major magnetic field dependence. These results indicate that a high pressure gas-filled cavity is potentially a viable technology for muon ionization cooling.

  3. Optimization of Beam Injection Into the First Accelerating Module at TTF With Cavity Dipole Mode Signals

    SciTech Connect

    Baboi, N.; Kreps, G.; Schlarb, H.; Wendt, M.; Frisch, J.; McCormick, D.; Ross, M.; Smith, T.; Napoly, O.; Paparella, R.G.; /DSM, DAPNIA, Saclay

    2006-04-10

    The TESLA Test Facility (TTF) is a user facility for intense VUV-FEL light. The facility is densely equipped with diagnostics, essential in obtaining the necessary beam parameters, in particular the low emittance. However there is no dedicated component for alignment of the beam in the accelerating modules, each containing eight superconducting cavities. Large beam offsets can lead to an increase of the beam emittance. The centering of the beam in these modules is therefore important, mostly at the low energy end. A misalignment of the first TTF module with respect to the gun axis has already been observed using cavity dipole modes. This paper presents the experimental results of the optimization of the beam injection into the first module, based on the monitoring of dipole modes through the couplers installed for wakefield damping. For this we use a spectrum analyzer together with a multiplexer. By scanning the beam position and tilt with two pairs of steerers, we can find the trajectory which minimizes the dipole modes amplitude. The impact of the beam steering in the module on the beam is discussed. A time domain setup is also being presented.

  4. Analog detection for cavity lifetime spectroscopy

    DOEpatents

    Zare, Richard N.; Harb, Charles C.; Paldus, Barbara A.; Spence, Thomas G.

    2001-05-15

    An analog detection system for determining a ring-down rate or decay rate 1/.tau. of an exponentially decaying ring-down beam issuing from a lifetime or ring-down cavity during a ring-down phase. Alternatively, the analog detection system determines a build-up rate of an exponentially growing beam issuing from the cavity during a ring-up phase. The analog system can be employed in continuous wave cavity ring-down spectroscopy (CW CRDS) and pulsed CRDS (P CRDS) arrangements utilizing any type of ring-down cavity including ring-cavities and linear cavities.

  5. Analog detection for cavity lifetime spectroscopy

    DOEpatents

    Zare, Richard N.; Harb, Charles C.; Paldus, Barbara A.; Spence, Thomas G.

    2003-01-01

    An analog detection system for determining a ring-down rate or decay rate 1/.tau. of an exponentially decaying ring-down beam issuing from a lifetime or ring-down cavity during a ring-down phase. Alternatively, the analog detection system determines a build-up rate of an exponentially growing beam issuing from the cavity during a ring-up phase. The analog system can be employed in continuous wave cavity ring-down spectroscopy (CW CRDS) and pulsed CRDS (P CRDS) arrangements utilizing any type of ring-down cavity including ring-cavities and linear cavities.

  6. Progress on a Be Cavity Design

    SciTech Connect

    Li, D.; Virostek, S.; Zisman, M. S.; Palmer, R.; Stratakis, D.

    2011-10-06

    Previous RF experiments with normal-conducting cavities have demonstrated that there is a significant degradation in maximum gradient when the cavity is subjected to a strong axial magnetic field. We have developed a model suggesting that a cavity with beryllium walls may perform better than copper cavities. In this paper we outline the issues that led us to propose fabricating a Be-wall cavity. We also discuss a concept for fabricating such a cavity and mention some of the manufacturing issues we expect to face.

  7. Progress on a Be Cavity Design

    SciTech Connect

    Li, D.; Palmer, R.; Stratakis, D.; Virostek, S.; Zisman, Michael S.

    2010-12-24

    Previous RF experiments with normal-conducting cavities have demonstrated that there is a significant degradation in maximum gradient when the cavity is subjected to a strong axial magnetic field. We have developed a model suggesting that a cavity with beryllium walls may perform better than copper cavities. In this paper we outline the issues that led us to propose fabricating a Be-wall cavity. We also discuss a concept for fabricating such a cavity and mention some of the manufacturing issues we expect to face.

  8. Quench Studies of Six High Temperature Nitrogen Doped 9 Cell Cavities for Use in the LCLS-II Baseline Prototype Cryomodule at Jefferson Laboratory

    SciTech Connect

    Palczewski, Ari; Geng, Rongli; Eremeev, Grigory; Reece, Charles

    2015-09-01

    Jefferson Lab (JLab) processed six nine-cell cavities as part of a small-scale production for LCLS-II cavity processing development utilizing the promising nitrogen-doping process. Various nitrogen-doping recipes have been scrutinized to optimize process parameters with the aim to guarantee an unloaded quality factor (Q_0) of 2.7∙1010 at an accelerating field (Eacc) of 16 MV/m at 2.0 K in the cryomodule. During the R&D phase the characteristic Q0 vs. Eacc performance curve of the cavities has been measured in JLab’s vertical test area at 2 K. The findings showed the characteristic rise of the Q0 with Eacc as expected from nitrogen-doping. Initially, five cavities achieved an average Q0 of 3.3·1010 at the limiting Eacc averaging to 16.8 MV/m, while one cavity experienced an early quench accompanied by an unusual Q_0 vs. Eacc curve. The project accounts for a cavity performance loss from the vertical dewar test (with or without the helium vessel) to the horizontal performance in a cryomodule, such that these results leave no save margin to the cryomodule specification. Consequently, a refinement of the nitrogen-doping has been initiated to guarantee an average quench field above 20 MV/m without impeding the Q_0. This paper covers the refinement work performed for each cavity, which depends on the initial results, as well as a quench analysis carried out before and after the rework during the vertical RF tests as far as applicable.

  9. Facing rim cavities fluctuation modes

    NASA Astrophysics Data System (ADS)

    Casalino, Damiano; Ribeiro, André F. P.; Fares, Ehab

    2014-06-01

    Cavity modes taking place in the rims of two opposite wheels are investigated through Lattice-Boltzmann CFD simulations. Based on previous observations carried out by the authors during the BANC-II/LAGOON landing gear aeroacoustic study, a resonance mode can take place in the volume between the wheels of a two-wheel landing gear, involving a coupling between shear-layer vortical fluctuations and acoustic modes resulting from the combination of round cavity modes and wheel-to-wheel transversal acoustic modes. As a result, side force fluctuations and tonal noise side radiation take place. A parametric study of the cavity mode properties is carried out in the present work by varying the distance between the wheels. Moreover, the effects due to the presence of the axle are investigated by removing the axle from the two-wheel assembly. The azimuthal properties of the modes are scrutinized by filtering the unsteady flow in narrow bands around the tonal frequencies and investigating the azimuthal structure of the filtered fluctuation modes. Estimation of the tone frequencies with an ad hoc proposed analytical formula confirms the observed modal properties of the filtered unsteady flow solutions. The present study constitutes a primary step in the description of facing rim cavity modes as a possible source of landing gear tonal noise.

  10. A STUDY OF FERRITE CAVITY.

    SciTech Connect

    ZHAO, Y.

    2002-04-19

    This note addresses the general concerns for the design of a ferrite cavity. The parameters are specified for the RCMS, for which the frequency ramp is in the range of 1.27 MHz to 6.44 MHz, or a ratio of 1:5.

  11. Fibre ring cavity semiconductor laser

    SciTech Connect

    Duraev, V P; Medvedev, S V

    2013-10-31

    This paper presents a study of semiconductor lasers having a polarisation maintaining fibre ring cavity. We examine the operating principle and report main characteristics of a semiconductor ring laser, in particular in single- and multiple-frequency regimes, and discuss its application areas. (lasers)

  12. "Grinding" cavities in polyurethane foam

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

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

  13. Piezoelectric tunable microwave superconducting cavity

    NASA Astrophysics Data System (ADS)

    Carvalho, N. C.; Fan, Y.; Tobar, M. E.

    2016-09-01

    In the context of engineered quantum systems, there is a demand for superconducting tunable devices, able to operate with high-quality factors at power levels equivalent to only a few photons. In this work, we developed a 3D microwave re-entrant cavity with such characteristics ready to provide a very fine-tuning of a high-Q resonant mode over a large dynamic range. This system has an electronic tuning mechanism based on a mechanically amplified piezoelectric actuator, which controls the resonator dominant mode frequency by changing the cavity narrow gap by very small displacements. Experiments were conducted at room and dilution refrigerator temperatures showing a large dynamic range up to 4 GHz and 1 GHz, respectively, and were compared to a finite element method model simulated data. At elevated microwave power input, nonlinear thermal effects were observed to destroy the superconductivity of the cavity due to the large electric fields generated in the small gap of the re-entrant cavity.

  14. Cavity Enhanced Velocity Modulation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Siller, Brian; Mills, Andrew; McCall, Benjamin J.

    2010-06-01

    Velocity modulation spectroscopy has traditionally been used with a unidirectional multipass White cell to obtain several passes through a plasma in order to obtain strong signals from the absorption of ions, but the total number of passes allowed by this type of setup is limited to ˜8. By placing an optical cavity around an N_2^+ plasma and locking the cavity to a Ti:Sapphire laser, the effective number of passes has been increased to several hundred. Demodulating the signal from the transmitted light at twice the plasma frequency (due to the symmetric nature of the cavity) gives a 2nd derivative lineshape for ions and a Gaussian lineshape for excited neutrals. N_2^+ and N_2^* have been observed to be 78° out of phase with one another. The different lineshapes and phases allow for discrimination and separation of the ion and neutral signals. The high intensity laser light within the cavity causes the transitions to saturate, which allows for the observation of lamb dips; this opens the door to sub-Doppler spectroscopy, as well as to studies of ion-neutral collisional rate coefficients.

  15. Particle-in-cell based parameter study of 12-cavity, 12-cathode rising-sun relativistic magnetrons for improved performance

    SciTech Connect

    Majzoobi, A.; Joshi, R. P. Neuber, A. A.; Dickens, J. C.

    2015-10-15

    Particle-in-cell simulations are performed to analyze the efficiency, output power and leakage currents in a 12-Cavity, 12-Cathode rising-sun magnetron with diffraction output (MDO). The central goal is to conduct a parameter study of a rising-sun magnetron that comprehensively incorporates performance enhancing features such as transparent cathodes, axial extraction, the use of endcaps, and cathode extensions. Our optimum results demonstrate peak output power of about 2.1 GW, with efficiencies of ∼70% and low leakage currents at a magnetic field of 0.45 Tesla, a 400 kV bias with a single endcap, for a range of cathode extensions between 3 and 6 centimeters.

  16. Optical cavity furnace for semiconductor wafer processing

    DOEpatents

    Sopori, Bhushan L.

    2014-08-05

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

  17. 21 CFR 872.3260 - Cavity varnish.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DENTAL DEVICES Prosthetic Devices § 872.3260 Cavity varnish. (a) Identification. Cavity varnish is a... restorative materials. The device is intended to prevent penetration of restorative materials, such as...

  18. Multipacting analysis for JLAB ampere class cavities

    SciTech Connect

    Genfa Wu; Mircea Stirbet; Haipeng Wang; Robert Rimmer; Evan Donoghue

    2005-07-10

    JLAB's ampere class 5-cell cavities require a moderate accelerating gradient (16.7 {approx} 20MV/m). Electron multipacting activity in the machine operating range can degrade the expected performance. A survey was conducted in the area of multipacting analysis for beta=1 electron cavity shapes, including options for the new high current cavity shape. The results obtained provided useful guidance to the final cavity shape adopted and to its expected performance.

  19. Modeling and cavity optimization of an external cavity semiconductor laser

    NASA Astrophysics Data System (ADS)

    Feies, Valentin I.; Montrosset, Ivo

    2004-09-01

    Semiconductor external cavity lasers (ECL) have a wide range of applications in the field of DWDM and measurement systems. One of their most important features is the continuous tuning without mode hopping in a wide wavelength range. In this paper we present a modelling approach for an ECL in Littman-Metcalf configuration carried out for optimising: 1) the laser diode position inside the cavity in order to maximize the range of continuous wavelength tuning without mode hopping and without cavity-length adjustment and 2) the choice of the detuning of the operating wavelength respect to the Bragg condition in order to minimize the four-wave mixing (FWM) effects and the effect of a non-perfect antireflection coating (ARC). A realistic example has been analyzed and therefore we considered: the wavelength dependence of the modal gain, linewidth enhancement factor and grating selectivity, as well as the modal refractive index change with carrier injection, operating wavelength and temperature. The implemented numerical tools allow also to obtain some specifications on the grating selectivity and the ARC design.

  20. High resolution MRI anatomy of the cat brain at 3 Tesla

    PubMed Central

    Gray-Edwards, Heather L.; Salibi, Nouha; Josephson, Eleanor M.; Hudson, Judith A.; Cox, Nancy R.; Randle, Ashley N.; McCurdy, Victoria J.; Bradbury, Allison M.; Wilson, Diane U.; Beyers, Ronald J.; Denney, Thomas S.; Martin, Douglas R.

    2014-01-01

    Background Feline models of neurologic diseases, such as lysosomal storage diseases, leukodystrophies, Parkinson’s disease, stroke and NeuroAIDS, accurately recreate many aspects of human disease allowing for comparative study of neuropathology and the testing of novel therapeutics. Here we describe in vivo visualization of fine structures within the feline brain that were previously only visible post mortem. New Method 3 Tesla MR images were acquired using T1-weighted (T1w) 3D magnetization-prepared rapid gradient echo (MPRAGE) sequence (0.4mm isotropic resolution) and T2-weighted (T2w) turbo spin echo (TSE) images (0.3×0.3×1 mm3 resolution). Anatomic structures were identified based on feline and canine histology. Results T2w high resolution MR images with detailed structural identification are provided in transverse, sagittal and dorsal planes. T1w MR images are provided electronically in three dimensions for unrestricted spatial evaluation. Comparison with Existing Methods Many areas of the feline brain previously unresolvable on MRI are clearly visible in three orientations, including the dentate, interpositus and fastigial cerebellar nuclei, cranial nerves, lateral geniculate nucleus, optic radiation, cochlea, caudal colliculus, temporal lobe, precuneus, spinocerebellar tract, vestibular nuclei, reticular formation, pyramids and rostral and middle cerebral arteries. Additionally, the feline brain is represented in 3 dimensions for the first time. Conclusions These data establish normal appearance of detailed anatomical structures of the feline brain, which provide reference when evaluating neurologic disease or testing efficacy of novel therapeutics in animal models. PMID:24525327

  1. Axonal diameter and density estimated with 7-Tesla hybrid diffusion imaging in transgenic Alzheimer rats

    NASA Astrophysics Data System (ADS)

    Daianu, Madelaine; Jacobs, Russell E.; Town, Terrence; Thompson, Paul M.

    2016-03-01

    Diffusion-weighted MR imaging (DWI) is a powerful tool to study brain tissue microstructure. DWI is sensitive to subtle changes in the white matter (WM), and can provide insight into abnormal brain changes in diseases such as Alzheimer's disease (AD). In this study, we used 7-Tesla hybrid diffusion imaging (HYDI) to scan 3 transgenic rats (line TgF344-AD; that model the full clinico-pathological spectrum of the human disease) ex vivo at 10, 15 and 24 months. We acquired 300 DWI volumes across 5 q-sampling shells (b=1000, 3000, 4000, 8000, 12000 s/mm2). From the top three b-value shells with highest signal-to-noise ratios, we reconstructed markers of WM disease, including indices of axon density and diameter in the corpus callosum (CC) - directly quantifying processes that occur in AD. As expected, apparent anisotropy progressively decreased with age; there were also decreases in the intra- and extra-axonal MR signal along axons. Axonal diameters were larger in segments of the CC (splenium and body, but not genu), possibly indicating neuritic dystrophy - characterized by enlarged axons and dendrites as previously observed at the ultrastructural level (see Cohen et al., J. Neurosci. 2013). This was further supported by increases in MR signals trapped in glial cells, CSF and possibly other small compartments in WM structures. Finally, tractography detected fewer fibers in the CC at 10 versus 24 months of age. These novel findings offer great potential to provide technical and scientific insight into the biology of brain disease.

  2. In vivo 7 Tesla imaging of the dentate granule cell layer in Schizophrenia

    PubMed Central

    Kirov, Ivan I.; Hardy, Caitlin J.; Matsuda, Kant; Messinger, Julie; Cankurtaran, Ceylan Z.; Warren, Melina; Wiggins, Graham C.; Perry, Nissa N.; Babb, James S.; Goetz, Raymond R.; George, Ajax; Malaspina, Dolores; Gonen, Oded

    2013-01-01

    PURPOSE The hippocampus is central to the pathophysiology of schizophrenia. Histology shows abnormalities in the dentate granule cell layer (DGCL), but its small size (~100 micron thickness) has precluded in vivo human studies. We used ultra high field magnetic resonance imaging (MRI) to compare DGCL morphology of schizophrenic patients to matched controls’. METHOD Bilateral hippocampi of 16 schizophrenia patients (10 male) 40.7±10.6 years old (mean ±standard deviation) were imaged at 7 Tesla MRI with heavily T2*-weighted gradient-echo sequence at 232 micron in-plane resolution (0.08 μL image voxels). Fifteen matched controls (8 male, 35.6±9.4 years old) and one ex vivo post mortem hippocampus (that also underwent histopathology) were scanned with same protocol. Three blinded neuroradiologists rated each DGCL on a qualitative scale of 1 to 6 (from “not discernible” to “easily visible, appearing dark gray or black”) and mean left and right DGCL scores were compared using a non-parametric Mann-Whitney test. RESULTS MRI identification of the DGCL was validated with histopathology. Mean right and left DGCL ratings in patients (3.2±1.0 and 3.5±1.2) were not statistically different from controls’ (3.9±1.1 and 3.8±0.8), but patients’ had a trend for lower right DGCL score (p=0.07), which was significantly associated with patient diagnosis (p=0.05). The optimal 48% sensitivity and 80% specificity for schizophrenia was achieved with a DGCL rating of ≤2. CONCLUSION Decreased contrast in the right DGCL in schizophrenia was predictive of schizophrenia diagnosis. Better utility of this metric as a schizophrenia biomarker may be achieved in future studies of patients with homogeneous disease subtypes and progression rates. PMID:23664589

  3. Gadolinium Enhanced MR Coronary Vessel Wall Imaging at 3.0 Tesla.

    PubMed

    Kelle, Sebastian; Schlendorf, Kelly; Hirsch, Glenn A; Gerstenblith, Gary; Fleck, Eckart; Weiss, Robert G; Stuber, Matthias

    2010-10-11

    Purpose. We evaluated the influence of the time between low-dose gadolinium (Gd) contrast administration and coronary vessel wall enhancement (LGE) detected by 3T magnetic resonance imaging (MRI) in healthy subjects and patients with coronary artery disease (CAD). Materials and Methods. Four healthy subjects (4 men, mean age 29 ± 3 years and eleven CAD patients (6 women, mean age 61 ± 10 years) were studied on a commercial 3.0 Tesla (T) whole-body MR imaging system (Achieva 3.0 T; Philips, Best, The Netherlands). T1-weighted inversion-recovery coronary magnetic resonance imaging (MRI) was repeated up to 75 minutes after administration of low-dose Gadolinium (Gd) (0.1 mmol/kg Gd-DTPA). Results. LGE was seen in none of the healthy subjects, however in all of the CAD patients. In CAD patients, fifty-six of 62 (90.3%) segments showed LGE of the coronary artery vessel wall at time-interval 1 after contrast. At time-interval 2, 34 of 42 (81.0%) and at time-interval 3, 29 of 39 evaluable segments (74.4%) were enhanced. Conclusion. In this work, we demonstrate LGE of the coronary artery vessel wall using 3.0 T MRI after a single, low-dose Gd contrast injection in CAD patients but not in healthy subjects. In the majority of the evaluated coronary segments in CAD patients, LGE of the coronary vessel wall was already detectable 30-45 minutes after administration of the contrast agent.

  4. Prostate cancer detection using multiparametric 3 – tesla MRI and fusion biopsy: preliminary results

    PubMed Central

    Mussi, Thais Caldara; Garcia, Rodrigo Gobbo; de Queiroz, Marcos Roberto Gomes; Lemos, Gustavo Caserta; Baroni, Ronaldo Hueb

    2016-01-01

    ABSTRACT Objective: To evaluate the diagnostic efficacy of transrectal ultrasonography (US) biopsy with imaging fusion using multiparametric (mp) magnetic resonance imaging (MRI) in patients with suspicion of prostate cancer (PCa), with an emphasis on clinically significant tumors according to histological criteria. Materials and Methods: A total of 189 consecutive US/MRI fusion biopsies were performed obtaining systematic and guided samples of suspicious areas on mpMRI using a 3 Tesla magnet without endorectal coil. Clinical significance for prostate cancer was established based on Epstein criteria. Results: In our casuistic, the average Gleason score was 7 and the average PSA was 5.0ng/mL. Of the 189 patients that received US/MRI biopsies, 110 (58.2%) were positive for PCa. Of those cases, 88 (80%) were clinically significant, accounting for 46.6% of all patients. We divided the MRI findings into 5 Likert scales of probability of having clinically significant PCa. The positivity of US/MRI biopsy for clinically significant PCa was 0%, 17.6% 23.5%, 53.4% and 84.4% for Likert scores 1, 2, 3, 4 and 5, respectively. There was a statistically significant difference in terms of biopsy results between different levels of suspicion on mpMRI and also when biopsy results were divided into groups of clinically non-significant versus clinically significant between different levels of suspicion on mpMRI (p-value <0.05 in both analyzes). Conclusion: We found that there is a significant difference in cancer detection using US/MRI fusion biopsy between low-probability and intermediate/high probability Likert scores using mpMRI. PMID:27532112

  5. A 0.5 Tesla Transverse-Field Alternating Magnetic Field Demagnetizer

    NASA Astrophysics Data System (ADS)

    Schillinger, W. E.; Morris, E. R.; Finn, D. R.; Coe, R. S.

    2015-12-01

    We have built an alternating field demagnetizer that can routinely achieve a maximum field of 0.5 Tesla. It uses an amorphous magnetic core with an air-cooled coil. We have started with a 0.5 T design, which satisfies most of our immediate needs, but we can certainly achieve higher fields. In our design, the magnetic field is transverse to the bore and uniform to 1% over a standard (25 mm) paleomagnetic sample. It is powered by a 1 kW power amplifier and is compatible with our existing sample handler for automated demagnetization and measurement (Morris et al., 2009). It's much higher peak field has enabled us to completely demagnetize many of the samples that previously we could not with commercial equipment. This capability is especially needed for high-coercivity sedimentary and igneous rocks that contain magnetic minerals that alter during thermal demagnetization. It will also enable detailed automated demagnetization of high coercivity phases in extraterrestrial samples, such as native iron, iron-alloy and sulfide minerals that are common in lunar rocks and meteorites. Furthermore, it has opened the door for us to use the rock-magnetic technique of component analysis, using coercivity distributions derived from very detailed AF demagnetization of NRM and remanence produced in the laboratory to characterize the magnetic mineralogy of sedimentary rocks. In addition to the many benefits this instrument has brought to our own research, a much broader potential impact is to replace the transverse coils in automated AF demagnetization systems, which typically are limited to peak fields around 0.1 T.

  6. Clinical Evaluation of Stereotactic Target Localization Using 3-Tesla MRI for Radiosurgery Planning

    SciTech Connect

    MacFadden, Derek; Zhang Beibei; Brock, Kristy K.; Hodaie, Mojgan; Laperriere, Normand; Schwartz, Michael; Tsao, May; Stainsby, Jeffrey; Lockwood, Gina; Mikulis, David; Menard, Cynthia

    2010-04-15

    Purpose: Increasing the magnetic resonance imaging (MRI) field strength can improve image resolution and quality, but concerns remain regarding the influence on geometric fidelity. The objectives of the present study were to spatially investigate the effect of 3-Tesla (3T) MRI on clinical target localization for stereotactic radiosurgery. Methods and Materials: A total of 39 patients were enrolled in a research ethics board-approved prospective clinical trial. Imaging (1.5T and 3T MRI and computed tomography) was performed after stereotactic frame placement. Stereotactic target localization at 1.5T vs. 3T was retrospectively analyzed in a representative cohort of patients with tumor (n = 4) and functional (n = 5) radiosurgical targets. The spatial congruency of the tumor gross target volumes was determined by the mean discrepancy between the average gross target volume surfaces at 1.5T and 3T. Reproducibility was assessed by the displacement from an averaged surface and volume congruency. Spatial congruency and the reproducibility of functional radiosurgical targets was determined by comparing the mean and standard deviation of the isocenter coordinates. Results: Overall, the mean absolute discrepancy across all patients was 0.67 mm (95% confidence interval, 0.51-0.83), significantly <1 mm (p < .010). No differences were found in the overall interuser target volume congruence (mean, 84% for 1.5T vs. 84% for 3T, p > .4), and the gross target volume surface mean displacements were similar within and between users. The overall average isocenter coordinate discrepancy for the functional targets at 1.5T and 3T was 0.33 mm (95% confidence interval, 0.20-0.48), with no patient-specific differences between the mean values (p >.2) or standard deviations (p >.1). Conclusion: Our results have provided clinically relevant evidence supporting the spatial validity of 3T MRI for use in stereotactic radiosurgery under the imaging conditions used.

  7. Discrete wavelength-locked external cavity laser

    NASA Technical Reports Server (NTRS)

    Pilgrim, Jeffrey S. (Inventor); Silver, Joel A. (Inventor)

    2005-01-01

    An external cavity laser (and method of generating laser light) comprising: a laser light source; means for collimating light output by the laser light source; a diffraction grating receiving collimated light; a cavity feedback mirror reflecting light received from the diffraction grating back to the diffraction grating; and means for reliably tuning the external cavity laser to discrete wavelengths.

  8. Photonic crystal cavities and integrated optical devices

    NASA Astrophysics Data System (ADS)

    Gan, Lin; Li, ZhiYuan

    2015-11-01

    This paper gives a brief introduction to our recent works on photonic crystal (PhC) cavities and related integrated optical structures and devices. Theoretical background and numerical methods for simulation of PhC cavities are first presented. Based on the theoretical basis, two relevant quantities, the cavity mode volume and the quality factor are discussed. Then the methods of fabrication and characterization of silicon PhC slab cavities are introduced. Several types of PhC cavities are presented, such as the usual L3 missing-hole cavity, the new concept waveguide-like parallel-hetero cavity, and the low-index nanobeam cavity. The advantages and disadvantages of each type of cavity are discussed. This will help the readers to decide which type of PhC cavities to use in particular applications. Furthermore, several integrated optical devices based on PhC cavities, such as optical filters, channel-drop filters, optical switches, and optical logic gates are described in both the working principle and operation characteristics. These devices designed and realized in our group demonstrate the wide range of applications of PhC cavities and offer possible solutions to some integrated optical problems.

  9. Power coupler for the ILC crab cavity

    SciTech Connect

    Burt, G.; Dexter, A.; Jenkins, R.; Beard, C.; Goudket, P.; McIntosh, P.A.; 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.

  10. Many-atom-cavity QED system with homogeneous atom-cavity coupling.

    PubMed

    Lee, Jongmin; Vrijsen, Geert; Teper, Igor; Hosten, Onur; Kasevich, Mark A

    2014-07-01

    We demonstrate a many-atom-cavity system with a high-finesse dual-wavelength standing wave cavity in which all participating rubidium atoms are nearly identically coupled to a 780-nm cavity mode. This homogeneous coupling is enforced by a one-dimensional optical lattice formed by the field of a 1560-nm cavity mode.

  11. A micropillar for cavity optomechanics

    SciTech Connect

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

    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.

  12. A micropillar for cavity optomechanics

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  13. Status of the ILC Crab Cavity Development

    SciTech Connect

    Burt, G.; Dexter, A.; Beard, C.; Goudket, P.; McIntosh, P.; Bellantoni, L.; 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.

  14. Magnetic spheres in microwave cavities

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    We apply Mie scattering theory to study the interaction of magnetic spheres with microwaves in cavities beyond the magnetostatic and rotating wave approximations. We demonstrate that both strong and ultrastrong coupling can be realized for stand alone magnetic spheres made from yttrium iron garnet (YIG), acting as an efficient microwave antenna. The eigenmodes of YIG spheres with radii of the order mm display distinct higher angular momentum character that has been observed in experiments.

  15. Grinding Inside A Toroidal Cavity

    NASA Technical Reports Server (NTRS)

    Mayer, Walter; Adams, James F.; Burley, Richard K.

    1987-01-01

    Weld lines ground smooth within about 0.001 in. Grinding tool for smoothing longitudinal weld lines inside toroidal cavity includes curved tunnel jig to guide grinding "mouse" along weld line. Curvature of tunnel jig matched to shape of toroid so grinding ball in mouse follows circular arc of correct radius as mouse is pushed along tunnel. Tool enables precise control of grindout shape, yet easy to use.

  16. Botryomycosis in a lung cavity

    PubMed Central

    Vinay, D; Ramasubramanian, V; Gopalakrishnan, Ram; Jessani, Laxman G

    2016-01-01

    Botryomycosis is a rare pyogranulomatous disease characterized by suppurative and often granulomatous bacterial infection of the skin, soft tissues and viscera. Only about 90 cases have been reported in world literature till date: 75% of them are cases of cutaneous botryomycosis. Of the 18 reported cases of primary pulmonary botryomycosis, only one had histologically proven botryomycosis in a lung cavity. We report here a case of primary pulmonary botryomycosis occurring in a lung cavity, which is to the best of our knowledge first such case from India. The index case was a 62 year old female who presented to us with recurrent episodes of non-massive streaky hemoptysis with CT chest revealing ‘Air Crescent’ sign with a probable fungal ball in a left upper lobe cavity. Left upper pulmonary lobectomy was done and histopathology of the cavitary tissue revealed Splendore-Hoeppli phenomenon and features suggestive of Botryomycosis. Tissue culture from the cavitary specimen grew Pseudomonas aeruginosa. Botryomycosis can mimic Aspergilloma radiologically as was seen in our case, but therapy is often a combination of both medical and surgical measures unlike Aspergilloma. PMID:27625451

  17. Optomechanic interactions in phoxonic cavities

    SciTech Connect

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

    2014-12-15

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

  18. Acoustic cavity technology for high performance injectors

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The feasibility of damping more than one mode of rocket engine combustion instability by means of differently tuned acoustic cavities sharing a common entrance was shown. Analytical procedures and acoustic modeling techniques for predicting the stability behavior of acoustic cavity designs in hot firings were developed. Full scale testing of various common entrance, dual cavity configurations, and subscale testing for the purpose of obtaining motion pictures of the cavity entrance region, to aid in determining the mechanism of cavity damping were the two major aspects of the program.

  19. Vented Cavity Radiant Barrier Assembly And Method

    DOEpatents

    Dinwoodie, Thomas L.; Jackaway, Adam D.

    2000-05-16

    A vented cavity radiant barrier assembly (2) includes a barrier (12), typically a PV module, having inner and outer surfaces (18, 22). A support assembly (14) is secured to the barrier and extends inwardly from the inner surface of the barrier to a building surface (14) creating a vented cavity (24) between the building surface and the barrier inner surface. A low emissivity element (20) is mounted at or between the building surface and the barrier inner surface. At least part of the cavity exit (30) is higher than the cavity entrance (28) to promote cooling air flow through the cavity.

  20. Controlled directional scattering cavity for tubular absorbers

    DOEpatents

    Winston, Roland

    1982-01-01

    A specular cavity is provided in which an optical receiver is emplaced. The cavity is provided with a series of V groove-like indentations (or pyramidal-type indentations) which redirect energy entering between the receiver and cavity structure onto the receiver. The aperture opening of each V groove is less than half the cavity opening and in most preferred embodiments, much less than half. This enables the optical receiver to be emplaced a distance g from the cavity wherein 0.414r

  1. LHC crab-cavity aspects and strategy

    SciTech Connect

    Calaga, R.; Tomas, R.; Zimmermann, F.

    2010-05-23

    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. Single-Bunch Electron Cloud Effects in the GLC/NLC, US-Cold and TESLA Low Emittance Transport Lines

    SciTech Connect

    Bates, D.

    2005-04-12

    This paper examines the severity of the electron cloud effects in the Low Emittance Transport (LET) of linear colliders including the Bunch-Compressor System (BCS) and Beam Delivery System (BDS). We examine the electron cloud effects in the normal-conducting GLC/NLC or X-Band, and the super-conducting US-Cold and TESLA linear collider designs through the use of specially developed computer simulation codes. An estimate of the critical cloud density is given for the BDS and BCS of the X-Band collider.

  3. Instability Thresholds And Generation of the Electron-Cloud in the GLC/NLC And Tesla Damping Rings

    SciTech Connect

    Pivi, M.

    2005-04-11

    In the beam pipe of the Damping Ring (DR) of a linear collider, an electron cloud may be produced by ionization of residual gas or photoelectrons and develop by the secondary emission process [1]. Coupling between the electrons and the circulating beam can cause coupled-bunch instabilities, coherent single-bunch instabilities or incoherent tune spreads that may lead to increased emittance, beam blow-up and ultimately to beam losses. We present recent computer simulation results for the electron cloud instability thresholds in the GLC/NLC (X-Band) main DR and for the TESLA DR.

  4. Novel Geometries for the LHC Crab Cavity

    SciTech Connect

    Hall, B.; Burt, G.; Smith, J. D.A.; Rimmer, R.; Wang, H.; Delayen, J.; Calaga, R.

    2009-05-01

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

  5. Control of Cavity Resonance Using Oscillatory Blowing

    NASA Technical Reports Server (NTRS)

    Scarfe, Alison Lamp; Chokani, Ndaona

    2000-01-01

    The near-zero net mass oscillatory blowing control of a subsonic cavity flow has been experimentally investigated. An actuator was designed and fabricated to provide both steady and oscillatory blowing over a range of blowing amplitudes and forcing frequencies. The blowing was applied just upstream of the cavity front Wall through interchangeable plate configurations These configurations enabled the effects of hole size, hole shape, and blowing angle to be examined. A significant finding is that in terms of the blowing amplitude, the near zero net mass oscillatory blowing is much more effective than steady blowing; momentum coefficients Lip two orders of magnitude smaller than those required for steady blowing are sufficient to accomplish the same control of cavity resonance. The detailed measurements obtained in the experiment include fluctuating pressure data within the cavity wall, and hot-wire measurements of the cavity shear layer. Spectral and wavelet analysis techniques are applied to understand the dynamics and mechanisms of the cavity flow with control. The oscillatory blowing, is effective in enhancing the mixing in the cavity shear layer and thus modifying the feedback loop associated with the cavity resonance. The nonlinear interactions in the cavity flow are no longer driven by the resonant cavity modes but by the forcing associated with the oscillatory blowing. The oscillatory blowing does not suppress the mode switching behavior of the cavity flow, but the amplitude modulation is reduced.

  6. Plasmonic Coupled Cavities on Moire Surfaces

    NASA Astrophysics Data System (ADS)

    Balci, Sinan; Kocabas, Askin; Karabiyik, Mustafa; Kocabas, Coskun; Aydinli, Atilla

    2010-03-01

    We investigate surface plasmon polariton (SPP) coupled cavity modes on Moire surfaces. An experimental study has been made of the propagation of SPPs on a thin silver surface that is textured with Moire surface pattern using interference lithography. The Moire surface contains periodic array of one dimensional cavities. The distance between the cavities can be controlled by changing the periodicities of Moire surface. When the SPP cavity separation is sufficiently small, we show splitting of strongly coupled plasmonic cavity modes through numerical simulations. Conversely, when the SPP cavity separation is sufficiently large, SPP cavity modes are found to be localized and do not show splitting of SPP cavity modes . This splitting of SPP cavity modes are well explained with a tight binding model that has been succesfully applied in photonic coupled cavities. Reflection measurements and numerical simulation of a large number of adjacent SPP cavities have shown a coupled resonator optical waveguide (CROW) type plasmonic waveguide band formation within the band gap region of unperturbed uniform grating.

  7. Novel Geometries for the LHC Crab Cavity

    SciTech Connect

    B. Hall,G. Burt,C. Lingwood,Robert Rimmer,Haipeng Wang; Hall, B.; Burt, G.; Lingwood, C.; Rimmer, Robert; Wang, Haipeng

    2010-05-01

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

  8. Novel Geometries for the LHC Crab Cavity

    SciTech Connect

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

    2010-05-23

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

  9. Shape Determination for Deformed Electromagnetic Cavities

    SciTech Connect

    Akcelik, Volkan; Ko, Kwok; Lee, Lie-Quan; Li, Zhenghai; Ng, Cho-Kuen; Xiao, Liling; /SLAC

    2007-12-10

    The measured physical parameters of a superconducting cavity differ from those of the designed ideal cavity. This is due to shape deviations caused by both loose machine tolerances during fabrication and by the tuning process for the accelerating mode. We present a shape determination algorithm to solve for the unknown deviations from the ideal cavity using experimentally measured cavity data. The objective is to match the results of the deformed cavity model to experimental data through least-squares minimization. The inversion variables are unknown shape deformation parameters that describe perturbations of the ideal cavity. The constraint is the Maxwell eigenvalue problem. We solve the nonlinear optimization problem using a line-search based reduced space Gauss-Newton method where we compute shape sensitivities with a discrete adjoint approach. We present two shape determination examples, one from synthetic and the other from experimental data. The results demonstrate that the proposed algorithm is very effective in determining the deformed cavity shape.

  10. Coupled Resonator Vertical Cavity Laser Diode

    SciTech Connect

    CHOQUETTE, KENT D.; CHOW, WENG W.; FISCHER, ARTHUR J.; GEIB, KENT M.; HOU, HONG Q.

    1999-09-16

    We report the operation of an electrically injected monolithic coupled resonator vertical cavity laser which consists of an active cavity containing In{sub x}Ga{sub 1{minus}x}As quantum wells optically coupled to a passive GaAs cavity. This device demonstrates novel modulation characteristics arising from dynamic changes in the coupling between the active and passive cavities. A composite mode theory is used to model the output modulation of the coupled resonator vertical cavity laser. It is shown that the laser intensity can be modulated by either forward or reverse biasing the passive cavity. Under forward biasing, the modulation is due to carrier induced changes in the refractive index, while for reverse bias operation the modulation is caused by field dependent cavity enhanced absorption.

  11. Cavity Optomechanics at Millikelvin Temperatures

    NASA Astrophysics Data System (ADS)

    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

  12. Cavities

    MedlinePlus

    ... decay at an early stage helps maintain the strength of the tooth and limits the chance of damage to the pulp. Fillings Fillings are made of various materials and may be put inside the tooth or ...

  13. Design, Construction, and Initial Test of High Spatial Resolution Thermometry Arrays for Detection of Surface Temperature Profiles on SRF Cavities in Super Fluid Helium

    SciTech Connect

    Ari Palczewski, Rongli Geng, Grigory Eremeev

    2011-07-01

    We designed and built two high resolution (0.6-0.55mm special resolution [1.1-1.2mm separation]) thermometry arrays prototypes out of the Allen Bradley 90-120 ohm 1/8 watt resistor to measure surface temperature profiles on SRF cavities. One array was designed to be physically flexible and conform to any location on a SRF cavity; the other was modeled after the common G-10/stycast 2850 thermometer and designed to fit on the equator of an ILC (Tesla 1.3GHz) SRF cavity. We will discuss the advantages and disadvantages of each array and their construction. In addition we will present a case study of the arrays performance on a real SRF cavity TB9NR001. TB9NR001 presented a unique opportunity to test the performance of each array as it contained a dual (4mm separation) cat eye defect which conventional methods such as OST (Oscillating Superleak second-sound Transducers) and full coverage thermometry mapping were unable to distinguish between. We will discuss the new arrays ability to distinguish between the two defects and their preheating performance.

  14. Tumours of the nasal cavity*

    PubMed Central

    Stünzi, H.; Hauser, B.

    1976-01-01

    Tumours of the nasal cavity are rare in domestic animals, most cases occurring in the dog. Epithelial tumours are the most common type in carnivores (dogs and cats). In general, the same types of tumour occur in domestic animals as occur in man. There was no significant predisposition for breed in dogs, but in both dogs and cats far more males than females were affected. Metastases occurred only rarely. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 9Fig. 10Fig. 11Fig. 12Fig. 5Fig. 6Fig. 7Fig. 8 PMID:1086156

  15. Cancer of the oral cavity.

    PubMed

    Montero, Pablo H; Patel, Snehal G

    2015-07-01

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

  16. [Dirofilaria in the abdominal cavity].

    PubMed

    Révész, Erzsébet; Markovics, Gabriella; Darabos, Zoltán; Tóth, Ildikó; Fok, Eva

    2008-10-01

    Number of cases of filariasis have been recently reported in the Hungarian medical literature, most of them caused by Dirofilaria repens . Dirofilaria repens is a mosquito-transmitted filarioid worm in the subcutaneous tissue of dogs and cats. Human infection manifests as either subcutaneous nodules or lung parenchymal disease, which may even be asymptomatic. The authors report a human Dirofilaria repens infection of the abdominal cavity in a 61-year-old man,who underwent laparotomy for acute abdomen. Intraoperatively, local peritonitis was detected caused by a white nemathhelminth, measured 8 cm in size. Histocytology confirmed that the infection was caused by Dirofilaria repens.

  17. Mass renormalization in cavity QED

    SciTech Connect

    Matloob, Reza

    2011-01-15

    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.

  18. Basketballs as spherical acoustic cavities

    NASA Astrophysics Data System (ADS)

    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.

  19. Subwavelength Nanopatch Cavities for Semiconductor Plasmon Lasers

    NASA Astrophysics Data System (ADS)

    Manolatou, Christina; Rana, Farhan

    2008-05-01

    We propose and analyze a family of nanoscale cavities for electrically-pumped surface-emitting semiconductor lasers that use surface plasmons to provide optical mode confinement in cavities which have dimensions in the 100-300 nm range. The proposed laser cavities are in many ways nanoscale optical versions of micropatch antennas that are commonly used at microwave/RF frequencies. Surface plasmons are not only used for mode confinement but also for output beam shaping to realize single-lobe far-field radiation patterns with narrow beam waists from subwavelength size cavities. We identify the cavity modes with the largest quality factors and modal gain, and show that in the near-IR wavelength range (1.0-1.6 microns) cavity losses (including surface plasmon losses) can be compensated by the strong mode confinement in the gain region provided by the surface plasmons themselves and the required material threshold gain values can be smaller than 700 1/cm.

  20. Cavity-enhanced spectroscopy in optical fibers.

    PubMed

    Gupta, Manish; Jiao, Hong; O'Keefe, Anthony

    2002-11-01

    Cavity-enhanced methods have been extended to fiber optics by use of fiber Bragg gratings (FBGs) as reflectors. High-finesse fiber cavities were fabricated from FBGs made in both germanium/boron-co-doped photosensitive fiber and hydrogen-loaded Corning SMF-28 fiber. Optical losses in these cavities were determined from the measured Fabry-Perot transmission spectra and cavity ring-down spectroscopy. For a 10-m-long single-mode fiber cavity, ring-down times in excess of 2 ms were observed at 1563.6 nm, and individual laser pulses were resolved. An evanescent-wave access block was produced within a fiber cavity, and an enhanced sensitivity to optical loss was observed as the external medium's refractive index was altered.

  1. Turbine disk cavity aerodynamics and heat transfer

    NASA Technical Reports Server (NTRS)

    Johnson, B. V.; Daniels, W. A.

    1992-01-01

    Experiments were conducted to define the nature of the aerodynamics and heat transfer for the flow within the disk cavities and blade attachments of a large-scale model, simulating the Space Shuttle Main Engine (SSME) turbopump drive turbines. These experiments of the aerodynamic driving mechanisms explored the following: (1) flow between the main gas path and the disk cavities; (2) coolant flow injected into the disk cavities; (3) coolant density; (4) leakage flows through the seal between blades; and (5) the role that each of these various flows has in determining the adiabatic recovery temperature at all of the critical locations within the cavities. The model and the test apparatus provide close geometrical and aerodynamic simulation of all the two-stage cavity flow regions for the SSME High Pressure Fuel Turbopump and the ability to simulate the sources and sinks for each cavity flow.

  2. Mounting system for optical frequency reference cavities

    NASA Technical Reports Server (NTRS)

    Notcutt, Mark (Inventor); Hall, John L. (Inventor); Ma, Long-Sheng (Inventor)

    2008-01-01

    A technique for reducing the vibration sensitivity of laser-stabilizing optical reference cavities is based upon an improved design and mounting method for the cavity, wherein the cavity is mounted vertically. It is suspended at one plane, around the spacer cylinder, equidistant from the mirror ends of the cavity. The suspension element is a collar of an extremely low thermal expansion coefficient material, which surrounds the spacer cylinder and contacts it uniformly. Once the collar has been properly located, it is cemented in place so that the spacer cylinder is uniformly supported and does not have to be squeezed at all. The collar also includes a number of cavities partially bored into its lower flat surface, around the axial bore. These cavities are support points, into which mounting base pins will be inserted. Hence the collar is supported at a minimum of three points.

  3. Cavity-Dumped Communication Laser Design

    NASA Technical Reports Server (NTRS)

    Roberts, W. T.

    2003-01-01

    Cavity-dumped lasers have significant advantages over more conventional Q-switched lasers for high-rate operation with pulse position modulation communications, including the ability to emit laser pulses at 1- to 10-megahertz rates, with pulse widths of 0.5 to 5 nanoseconds. A major advantage of cavity dumping is the potential to vary the cavity output percentage from pulse to pulse, maintaining the remainder of the energy in reserve for the next pulse. This article presents the results of a simplified cavity-dumped laser model, establishing the requirements for cavity efficiency and projecting the ultimate laser efficiency attainable in normal operation. In addition, a method of reducing or eliminating laser dead time is suggested that could significantly enhance communication capacity. The design of a laboratory demonstration laser is presented with estimates of required cavity efficiency and demonstration potential.

  4. Rebuild of Capture Cavity 1 at Fermilab

    SciTech Connect

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

    2014-01-01

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

  5. Coupled-cavity drift-tube linac

    DOEpatents

    Billen, James H.

    1996-01-01

    A coupled-cavity drift-tube linac (CCDTL) combines features of the Alvarez drift-tube linac (DTL) and the .pi.-mode coupled-cavity linac (CCL). In one embodiment, each accelerating cavity is a two-cell, 0-mode DTL. The center-to-center distance between accelerating gaps is .beta..lambda., where .lambda. is the free-space wavelength of the resonant mode. Adjacent accelerating cavities have oppositely directed electric fields, alternating in phase by 180 degrees. The chain of cavities operates in a .pi./2 structure mode so the coupling cavities are nominally unexcited. The CCDTL configuration provides an rf structure with high shunt impedance for intermediate velocity charged particles, i.e., particles with energies in the 20-200 MeV range.

  6. Coupled-cavity drift-tube linac

    DOEpatents

    Billen, J.H.

    1996-11-26

    A coupled-cavity drift-tube linac (CCDTL) combines features of the Alvarez drift-tube linac (DTL) and the {pi}-mode coupled-cavity linac (CCL). In one embodiment, each accelerating cavity is a two-cell, 0-mode DTL. The center-to-center distance between accelerating gaps is {beta}{lambda}, where {lambda} is the free-space wavelength of the resonant mode. Adjacent accelerating cavities have oppositely directed electric fields, alternating in phase by 180 degrees. The chain of cavities operates in a {pi}/2 structure mode so the coupling cavities are nominally unexcited. The CCDTL configuration provides an rf structure with high shunt impedance for intermediate velocity charged particles, i.e., particles with energies in the 20-200 MeV range. 5 figs.

  7. Breakthrough: Record-Setting Cavity

    ScienceCinema

    Ciovati, Gianluigi

    2016-07-12

    Gianluigi "Gigi" Ciovati, a superconducting radiofrequency scientist, discusses how scientists at the U.S. Department of Energy's Jefferson Lab in Newport News, VA, used ARRA funds to fabricate a niobium cavity for superconducting radiofrequency accelerators that has set a world record for energy efficiency. Jefferson Lab's scientists developed a new, super-hot treatment process that could soon make it possible to produce cavities more quickly and at less cost, benefitting research and healthcare around the world. Accelerators are critical to our efforts to study the structure of matter that builds our visible universe. They also are used to produce medical isotopes and particle beams for diagnosing and eradicating disease. And they offer the potential to power future nuclear power plants that produce little or no radioactive waste.around the world. Accelerators are critical to our efforts to study the structure of matter that builds our visible universe. They also are used to produce medical isotopes and particle beams for diagnosing and eradicating disease. And they offer the potential to power future nuclear power plants that produce little or no radioactive waste.

  8. SPINNING MOTIONS IN CORONAL CAVITIES

    SciTech Connect

    Wang, Y.-M.; Stenborg, G. E-mail: guillermo.stenborg.ctr.ar@nrl.navy.mi

    2010-08-20

    In movies made from Fe XII 19.5 nm images, coronal cavities that graze or are detached from the solar limb appear as continually spinning structures, with sky-plane projected flow speeds in the range 5-10 km s{sup -1}. These whirling motions often persist in the same sense for up to several days and provide strong evidence that the cavities and the immediately surrounding streamer material have the form of helical flux ropes viewed along their axes. A pronounced bias toward spin in the equatorward direction is observed during 2008. We attribute this bias to the poleward concentration of the photospheric magnetic flux near sunspot minimum, which leads to asymmetric heating along large-scale coronal loops and tends to drive a flow from higher to lower latitudes; this flow is converted into an equatorward spinning motion when the loops pinch off to form a flux rope. As sunspot activity increases and the polar fields weaken, we expect the preferred direction of the spin to reverse.

  9. Breakthrough: Record-Setting Cavity

    SciTech Connect

    Ciovati, Gianluigi

    2012-03-01

    Gianluigi "Gigi" Ciovati, a superconducting radiofrequency scientist, discusses how scientists at the U.S. Department of Energy's Jefferson Lab in Newport News, VA, used ARRA funds to fabricate a niobium cavity for superconducting radiofrequency accelerators that has set a world record for energy efficiency. Jefferson Lab's scientists developed a new, super-hot treatment process that could soon make it possible to produce cavities more quickly and at less cost, benefitting research and healthcare around the world. Accelerators are critical to our efforts to study the structure of matter that builds our visible universe. They also are used to produce medical isotopes and particle beams for diagnosing and eradicating disease. And they offer the potential to power future nuclear power plants that produce little or no radioactive waste.around the world. Accelerators are critical to our efforts to study the structure of matter that builds our visible universe. They also are used to produce medical isotopes and particle beams for diagnosing and eradicating disease. And they offer the potential to power future nuclear power plants that produce little or no radioactive waste.

  10. Compact Superconducting Crabbing and Deflecting Cavities

    SciTech Connect

    De Silva, Payagalage Subashini Uddika

    2012-09-01

    Recently, new geometries for superconducting crabbing and deflecting cavities have been developed that have significantly improved properties over those the standard TM{sub 110} cavities. They are smaller, have low surface fields, high shunt impedance and, more importantly for some of them, no lower-order-mode with a well-separated fundamental mode. This talk will present the status of the development of these cavities.

  11. Continuously tunable, split-cavity gyrotrons

    NASA Astrophysics Data System (ADS)

    Brand, G. F.; Gross, M.

    1985-12-01

    Attention is given to a gyrotron cavity configuration which is split in halves longitudinally, to allow any frequency lying between the fixed cavity resonance to be assessed by mechanically changing the separation of the two halves. Experimental results are presented which demonstrate that the rate-of-change in resonant frequency with separation is greatest if the minor axis of the cavity cross section is the one undergoing change. Excellent agreement with theory is noted for these results.

  12. Resonant-cavity antenna for plasma heating

    DOEpatents

    Perkins, Jr., Francis W.; Chiu, Shiu-Chu; Parks, Paul; Rawls, John M.

    1987-01-01

    Disclosed is a resonant coil cavity wave launcher for energizing a plasma immersed in a magnetic field. Energization includes launching fast Alfven waves to excite ion cyclotron frequency resonances in the plasma. The cavity includes inductive and capacitive reactive members spaced no further than one-quarter wavelength from a first wall confinement chamber of the plasma. The cavity wave launcher is energized by connection to a waveguide or transmission line carrying forward power from a remote radio frequency energy source.

  13. Outbursts and cavities in comets

    NASA Astrophysics Data System (ADS)

    Ipatov, Sergei

    Based on analysis of the images made during the first 13 minutes after the collision of the impact module of the Deep Impact (DI) spacecraft with Comet 9P/Tempel 1, Ipatov & A'Hearn [1] studied time variations of ejection of material after this impact. They showed that, besides the normal ejection, at time t_{e} after the DI collision between 8 s and 60 s there was a considerable additional ejection (a triggered outburst) of small (micron size) particles. It increased the mean velocities of observed small ejected particles (compared with the normal ejection). The outburst could be caused by excavation of a large cavity with dust and gas under pressure. The largest cavity excavated after the collision could be relatively deep because a considerable excess ejection lasted during about 50 s. Schultz et al. [2] concluded that the diameter d_{tc} of the DI transient crater was about 200 m. Some authors support smaller values of d_{tc}. The depth of the DI crater at t_{e}=8 s was estimated in [3] to be about 6 m for d_{tc}=200 m and 4 m for d_{tc}=100 m. The distance between the pre-impact surface of Comet 9P/Tempel 1 and the upper border of the largest excavated cavity equal to about 4-6 m, and sizes of particles inside the cavities of a few microns are in good agreement with the results obtained by Kossacki & Szutowicz [4]. In their models of the explosion of Comet 17P/Holmes, the initial sublimation front of the CO ice was located at a depth of 4 m, 10 m, or 20 m, and calculations were finished when the CO pressure exceeded the threshold value 10 kPa. It was shown that the pressure of CO vapor can rise to this value only when the nucleus is composed of very fine grains, a few microns in radius. The porous structure of comets provides enough space for sublimation. The projection of the velocity of the leading edge of the DI cloud (onto the plane perpendicular to the line of sight) was about 100-200 m/s and is typical for outburst particles ejected from comets

  14. Cavity quantum electrodynamics: coherence in context.

    PubMed

    Mabuchi, H; Doherty, A C

    2002-11-15

    Modern cavity quantum electrodynamics (cavity QED) illuminates the most fundamental aspects of coherence and decoherence in quantum mechanics. Experiments on atoms in cavities can be described by elementary models but reveal intriguing subtleties of the interplay of coherent dynamics with external couplings. Recent activity in this area has pioneered powerful new approaches to the study of quantum coherence and has fueled the growth of quantum information science. In years to come, the purview of cavity QED will continue to grow as researchers build on a rich infrastructure to attack some of the most pressing open questions in micro- and mesoscopic physics.

  15. Quantum teleportation with atoms trapped in cavities

    SciTech Connect

    Cho, Jaeyoon; Lee, Hai-Woong

    2004-09-01

    We propose a scheme to implement the quantum teleportation protocol with single atoms trapped in cavities. The scheme is based on the adiabatic passage and the polarization measurement. We show that it is possible to teleport the internal state of an atom trapped in a cavity to an atom trapped in another cavity with the success probability of 1/2 and the fidelity of 1. The scheme is resistant to a number of considerable imperfections such as the violation of the Lamb-Dicke condition, weak atom-cavity coupling, spontaneous emission, and detection inefficiency.

  16. Mechanical Properties of Ingot Nb Cavities

    SciTech Connect

    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.

  17. Cavity-locked ring down spectroscopy

    DOEpatents

    Zare, Richard N.; Paldus, Barbara A.; Harb, Charles C.; Spence, Thomas

    2000-01-01

    Distinct locking and sampling light beams are used in a cavity ring-down spectroscopy (CRDS) system to perform multiple ring-down measurements while the laser and ring-down cavity are continuously locked. The sampling and locking light beams have different frequencies, to ensure that the sampling and locking light are decoupled within the cavity. Preferably, the ring-down cavity is ring-shaped, the sampling light is s-polarized, and the locking light is p-polarized. Transmitted sampling light is used for ring-down measurements, while reflected locking light is used for locking in a Pound-Drever scheme.

  18. Design of the ILC Crab Cavity System

    SciTech Connect

    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, A.; 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.

  19. Comparison of coherently coupled multi-cavity and quantum dot embedded single cavity systems.

    PubMed

    Kocaman, Serdar; Sayan, Gönül Turhan

    2016-12-12

    Temporal group delays originating from the optical analogue to electromagnetically induced transparency (EIT) are compared in two systems. Similar transmission characteristics are observed between a coherently coupled high-Q multi-cavity array and a single quantum dot (QD) embedded cavity in the weak coupling regime. However, theoretically generated group delay values for the multi-cavity case are around two times higher. Both configurations allow direct scalability for chip-scale optical pulse trapping and coupled-cavity quantum electrodynamics (QED).

  20. Mini-cavity-dumped laser

    NASA Technical Reports Server (NTRS)

    Reed, E.

    1981-01-01

    Lasers for use in high precision satellite ranging systems consist typically of an oscillator followed by several amplifier stages. While the shortest optical pulses are achieved by using a mode locked oscillator, such an oscillator is incompatible with the compact design needed in future, highly mobile systems. The laser oscillator achieves pulse lengths approaching those obtainable by mode locking, but in a much more compact and stable design. The oscillator uses two LiNbO3 Pockels cells inside the resonator. One Q-switches the oscillator, and the other is used in a pulse slicing scheme to cavity dump a portion of the circulating optical energy. The length of the optical output pulse measured at 425 + or - 50 picoseconds.

  1. Slow plasmons in grating cavities

    NASA Astrophysics Data System (ADS)

    Aydinli, Atilla; Karademir, Ertugrul; Balci, Sinan; Kocabas, Coskun

    2016-03-01

    Recent research on surface plasmon polaritons and their applications have brought forward a wealth of information and continues to be of interest to many. In this report, we concentrate on propagating surface plasmon polaritons (SPPs) and their interaction with matter. Using grating based metallic structures, it is possible to control the electrodynamics of propagating SPPs. Biharmonic gratings loaded with periodic Si stripes allow excitation of SPPs that are localized inside the band gap with grating coupling. The cavity state is formed due to periodic effective index modulation obtained by one harmonic of the grating and loaded Si stripes. More complicated grating structures such as metallic Moiré surfaces have also been shown to form a localized state inside the band gap when excited with Kretschmann configuration.

  2. Design and 3D simulation of a two-cavity wide-gap relativistic klystron amplifier with high power injection

    SciTech Connect

    Bai Xianchen; Yang Jianhua; Zhang Jiande

    2012-08-15

    By using an electromagnetic particle-in-cell (PIC) code, an S-band two-cavity wide-gap klystron amplifier (WKA) loaded with washers/rods structure is designed and investigated for high power injection application. Influences of the washers/rods structure on the high frequency characteristics and the basic operation of the amplifier are presented. Generally, the rod structure has great impacts on the space-charge potential depression and the resonant frequency of the cavities. Nevertheless, if only the resonant frequency is tuned to the desired operation frequency, effects of the rod size on the basic operation of the amplifier are expected to be very weak. The 3-dimension (3-D) PIC simulation results show an output power of 0.98 GW corresponding to an efficiency of 33% for the WKA, with a 594 keV, 5 kA electron beam guided by an external magnetic field of 1.5 Tesla. Moreover, if a conductive plane is placed near the output gap, such as the electron collector, the beam potential energy can be further released, and the RF power can be increased to about 1.07 GW with the conversion efficiency of about 36%.

  3. The Heliosphere as Resonant Cavity

    NASA Technical Reports Server (NTRS)

    Bames, Aaron

    1999-01-01

    If a disturbance in the supersonic solar wind reaches the heliospheric shock, a number of events ensue. First, the shock itself responds with inward or outward motion. Secondly, the disturbance propagates outward through the heliosheath as a sound or magnetoacoustic wave; eventually it reaches the heliopause and is (partially) reflected back toward the termination shock. The reflected wave can return to the shock, affecting the shock's motion, and be reflected yet again. The repetition of these processes can produce a 'ringing' in the heliosheath. This suggests that it may be useful to regard the heliosheath as a resonant acoustic cavity with inner and outer boundaries at the termination shock and heliopause, respectively. To evaluate this concept we have developed a simple model of small-amplitude resonant oscillations in an outwardly flowing gas, with appropriate boundary conditions (shock on the interior, tangential discontinuity on the exterior boundary). The fundamental mode of oscillation has a period of order T approx. 2D/C, where C is the speed of sound in the heliosheath and D is the distance between the two boundaries. Typical numerical models of the heliosphere give C approx. 200-500 km/s and D approx. 20 - 100 AU, giving T approx. 0.5 - 2.5 years. Hence we suggest that motions of the heliosheath and termination shock will occur with time scales of the order of a year, and are the consequence of the resonant nature of the heliospheric cavity rather than the history of variation at the Sun and/or in the solar wind. In particular, we suggest that the motion of the termination shock may be unrelated to solar variations over the time scale of the sunspot cycle.

  4. Geophysical observations at cavity collapse

    NASA Astrophysics Data System (ADS)

    Jousset, Philippe; Bazargan-Sabet, Behrooz; Lebert, François; Bernardie, Séverine; Gourry, Jean-Christophe

    2010-05-01

    In Lorraine region (France) salt layers at about 200 meters depth are exploited by Solvay using solution mining methodology which consists in extracting the salt by dissolution, collapsing the cavern overburden during the exploitation phase and finally reclaiming the landscape by creating a water area. In this process, one of the main challenges for the exploiting company is to control the initial 120-m diameter collapse so as to minimize possible damages. In order to detect potential precursors and understand processes associated with such collapses, a wide series of monitoring techniques including micro seismics, broad-band seismology, hydro-acoustic, electromagnetism, gas probing, automatic leveling, continuous GPS, continuous gravity and borehole extensometry was set-up in the frame of an in-situ study carried out by the "Research Group for the Impact and Safety of Underground Works" (GISOS, France). Equipments were set-up well before the final collapse, giving a unique opportunity to analyze a great deal of information prior to and during the collapse process which has been successfully achieved on February the 13th, 2009 by controlling the cavity internal pressure. In this work, we present the results of data recorded by a network of 3 broadband seismometers, 2 accelerometers, 2 tilt-meters and a continuously gravity meter. We relate the variations of the brine pumping rate with the evolutions of the induced geophysical signals and finally we propose a first mechanical model for describing the controlled collapse. Beyond the studied case, extrapolation of the results obtained might contribute to the understanding of uncontrolled cavity collapses, such as pit-craters or calderas at volcanoes.

  5. Survival analysis of a critical resource for cavity-nesting communities: patterns of tree cavity longevity.

    PubMed

    Edworthy, Amanda B; Wiebe, Karen L; Martin, Kathy

    2012-09-01

    Tree cavities are a vital multi-annual resource used by cavity-nesting birds and mammals for nesting and shelter. The abundance of this resource will be influenced by the rates at which cavities are created and destroyed. We applied the demographic concepts of survival and longevity to populations of tree holes to investigate rates of loss for cavities in three tree species, as well as how characteristics of nest trees, habitat type, and species of excavator affected the persistence of tree cavities in trembling aspen, Populus tremuloides (95% of cavities were in aspen trees), in interior British Columbia, Canada. By modeling survival of 1635 nesting cavities in aspen over a time span of 16 years, we found that the decay stage of the nest tree was the most important factor determining cavity longevity. Cavities in trees with advanced decay had a relatively short median longevity of 7 years (95% CI 6-9 years), whereas those in living trees had a median longevity of more than 15 years. We found that cavity longevity was greater in continuous forest than in aspen grove habitat. Interestingly, cavities formed by weak excavators survived as long as those created by Northern Flickers (Colaptes auratus), despite occurring in more decayed tree stems. Thus, weak excavators may be selecting for characteristics that make a tree persistent, such as a broken top. Our results indicate that retention of cavities in large, live aspen trees is necessary to conserve persistent cavities, and that cavity longevity will have a large effect on the structure and function of cavity-using vertebrate communities.

  6. Hydrogen masers with cavity frequency switching servos

    NASA Technical Reports Server (NTRS)

    Peters, Harry E.; Owings, H. B.; Koppang, Paul A.

    1990-01-01

    The stability of the free-running hydrogen maser is limited by pulling of the unperturbed hydrogen transition frequency due to instability of the cavity resonance frequency. While automatic spin-exchange tuning is in principle the more basic and accurate method, the required beam intensity switching and the long servo time constant result in reduced stability for measuring intervals up to 10(exp 6) seconds. More importantly, the spin-exchange tuning method requires a second stable frequency source as a reference, ideally a second hydrogen maser, to get the best results. The cavity frequency switching servo, on the other hand, has very little effect on the maser short term stability, and is fast enough to correct for cavity drift while maintaining the cavity at the spin-exchange tuned offset required to minimize instability due to beam intensity fluctuations. Not only does the cavity frequency switching servo not require a second stable frequency source, but the frequency reference is the atomic hydrogen radiated beam signal, so that no extra RF connections need be made to the cavity, and externally generated signals that would perturb the hydrogen atom need not be transmitted through the cavity. The operation of the cavity frequency switching stabilization method is discussed and the transient response of the servo and certain other aspects of the technique that have potential for achieving improved basic accuracy are illustrated.

  7. Geometric Model of a Coronal Cavity

    NASA Technical Reports Server (NTRS)

    Kucera, Therese A.; Gibson, S. E.; Ratawicki, D.; Dove, J.; deToma, G.; Hao, J.; Hudson, H. S.; Marque, C.; McIntosh, P. S.; Reeves, K. K.; Schmidt, D. J.; Sterling, A. C.; Tripathi, D. K.; Williams, D. R.; Zhang, M.

    2010-01-01

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

  8. Compact microwave cavity for hydrogen atomic clock

    NASA Technical Reports Server (NTRS)

    Zhang, Dejun; Zhang, Yan; Fu, Yigen; Zhang, Yanjun

    1992-01-01

    A summary is presented that introduces the compact microwave cavity used in the hydrogen atomic clock. Special emphasis is placed on derivation of theoretical calculating equations of main parameters of the microwave cavity. A brief description is given of several methods for discriminating the oscillating modes. Experimental data and respective calculated values are also presented.

  9. The ADMX Microwave Cavity: Present and future

    NASA Astrophysics Data System (ADS)

    Woollett, Nathan; ADMX Collaboration

    2017-01-01

    The Axion Dark Matter eXperiment (ADMX), a direct-detection axion search, uses a tunable resonant cavity to enhance axion to photon conversion rates to a detectable level when the cavity resonance matches the mass of the axion. It has successfully taken data in the 460 - 890 MHz frequency range and is now probing a similar range with much higher sensitivity. However the axion mass is unknown and may be at higher frequencies than the currently operating system. In anticipation of future runs with an increased mass range, ADMX is conducting extensive research and development of microwave cavities. These developments include photonic band-gap cavities, multi-vane cavities, partitioned cavities, in-phase coupled cavities, and superconducting hybrid cavities. Many of these projects are in different stages between simulations and testing of physical prototypes. The status and current objectives of these projects will be presented. Supported by DOE Grants DE-SC0010280, DE-FG02-96ER40956, DE-AC52-07NA27344, DE-AC03-76SF00098, the Heising-Simons Foundation and the LLNL, FNAL and PNNL LDRD program.

  10. Fast tuning of superconducting microwave cavities

    SciTech Connect

    Sandberg, M.; Wilson, C. M.; Persson, F.; Johansson, G.; Shumeiko, V.; Bauch, T.; Duty, T.; Delsing, P.

    2008-11-07

    Photons are fundamental excitations of electromagnetic fields and can be captured in cavities. For a given cavity with a certain size, the fundamental mode has a fixed frequency f which gives the photons a specific 'color'. The cavity also has a typical lifetime {tau}, which results in a finite linewidth {delta}f. If the size of the cavity is changed fast compared to {tau}, and so that the frequency change {delta}f>>{delta}f, then it is possible to change the 'color' of the captured photons. Here we demonstrate superconducting microwave cavities, with tunable effective lengths. The tuning is obtained by varying a Josephson inductance at one end of the cavity. We show data on four different samples and demonstrate tuning by several hundred linewidths in a time {delta}t<<{tau}. Working in the few photon limit, we show that photons stored in the cavity at one frequency will leak out from the cavity with the new frequency after the detuning. The characteristics of the measured devices make them suitable for different applications such as dynamic coupling of qubits and parametric amplification.

  11. Large grain cavities from pure niobium ingot

    DOEpatents

    Myneni, Ganapati Rao [Yorktown, VA; Kneisel, Peter [Williamsburg, VA; Cameiro, Tadeu [McMurray, PA

    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.

  12. Folded cavity design for a ruby resonator

    NASA Technical Reports Server (NTRS)

    Arunkumar, K. A.; Trolinger, James D.

    1988-01-01

    A folded cavity laser resonator operating in the TEM(00) mode has been built and tested. The new oscillator configuration leads to an increase in efficiency and to better line narrowing due to the increased number of passes through the laser rod and tuning elements, respectively. The modification is shown to lead to cavity ruggedization.

  13. 21 CFR 872.3260 - Cavity varnish.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cavity varnish. 872.3260 Section 872.3260 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... device that consists of a compound intended to coat a prepared cavity of a tooth before insertion...

  14. 21 CFR 872.3260 - Cavity varnish.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cavity varnish. 872.3260 Section 872.3260 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... device that consists of a compound intended to coat a prepared cavity of a tooth before insertion...

  15. 21 CFR 872.3260 - Cavity varnish.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cavity varnish. 872.3260 Section 872.3260 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... device that consists of a compound intended to coat a prepared cavity of a tooth before insertion...

  16. 21 CFR 872.3260 - Cavity varnish.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cavity varnish. 872.3260 Section 872.3260 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... device that consists of a compound intended to coat a prepared cavity of a tooth before insertion...

  17. Developing of superconducting niobium cavities for accelerators

    NASA Astrophysics Data System (ADS)

    Pobol, I. L.; Yurevich, S. V.

    2015-11-01

    The results of a study of structure and mechanical properties of welding joints, superconducting characteristics of the material after joining of welded components of superconducting radio frequency cavities are presented. The paper also describes the results of testing of the RF 1.3 GHz single-cell niobium cavity manufactured in the PTI NAS Belarus.

  18. Tunable Microwave Cavity For Ion Source

    NASA Technical Reports Server (NTRS)

    Nakanishi, Shigeo; Calco, Frank S.; Scarpelli, August R.

    1988-01-01

    Movable probe and tuning wall adjusted to obtain resonance at microwave frequency used to generate plasma in cell at one end of microwave cavity. Electroless discharge without disadvantages of dc-cathode-discharge and RF-induction methods. To achieve precise positioning, coaxial probe extends into microwave cavity through tube.

  19. Performance Of Superconducting-Cavity Maser

    NASA Technical Reports Server (NTRS)

    Dick, G. John; Wang, Rabi T.

    1991-01-01

    Report describes experiments on operation of superconducting-cavity maser - all-cryogenic oscillator. Operates with degree of stability, at short measuring times, superior to that achievable by any other means. All components designed for cryogenic operation and stabilizing cavity very rigid, consisting of sapphire filling coated with lead.

  20. A 4 Tesla Superconducting Magnet Developed for a 6 Circle Huber Diffractometer at the XMaS Beamline

    SciTech Connect

    Thompson, P. B. J.; Brown, S. D.; Bouchenoire, L.; Mannix, D.; Paul, D. F.; Lucas, C. A.; Kervin, J.; Cooper, M. J.; Arakawa, P.; Laughon, G.

    2007-01-19

    We report here on the development and testing of a 4 Tesla cryogen free superconducting magnet designed to fit within the Euler cradle of a 6 circle Huber diffractometer, allowing scattering in both the vertical and horizontal planes. The geometry of this magnet allows the field to be applied in three orientations. The first being along the beam direction, the second with the field transverse to the beam direction a horizontal plane and finally the field can be applied vertically with respect to the beam. The magnet has a warm bore and an open geometry of 180 deg. , allowing large access to reciprocal space. A variable temperature insert has been developed, which is capable of working down to a temperature of 1.7 K and operating over a wide range of angles whilst maintaining a temperature stability of a few mK. Initial ferromagnetic diffraction measurements have been carried out on single crystal Tb and Dy samples.

  1. MHD seawater thruster performance: A comparison of predictions with experimental results from a two Tesla test facility

    SciTech Connect

    Picologlou, B.F.; Doss, E.D.; Geyer, H.K. ); Sikes, W.C.; Ranellone, R.F. )

    1992-01-01

    A two Tesla test facility was designed, built, and operated to investigate the performance of magnetohydrodynamic (MHD) seawater thrusters. The results of this investigation are used to validate a design oriented MHD thruster performance computer code. The thruster performance code consists of a one-dimensional MHD hydrodynamic model coupled to a two-dimensional electrical model. The code includes major loss mechanisms affecting the performance of the thruster. Among these losses are the joule dissipation losses, frictional losses, electrical end losses, and single electrode potential losses. The facility test loop, its components, and their design are presented in detail. Additionally, the test matrix and its rationale are discussed. Representative experimental results of the test program are presented, and are compared to pretest computer model predictions. Good agreement between predicted and measured data has served to validate the thruster performance computer models.

  2. Recent Electron-Cloud Simulation Results for the Main Damping Rings of the NLC and the TESLA Linear Colliders

    SciTech Connect

    Pivi, Mauro T F

    2003-05-19

    In the beam pipe of the Main Damping Ring (MDR) of the Next Linear Collider (NLC), ionization of residual gases and secondary emission give rise to an electron-cloud which stabilizes to equilibrium after few bunch trains. In this paper, we present recent computer simulation results for the main features of the electron cloud at the NLC and preliminary simulation results for the TESLA main damping rings, obtained with the code POSINST that has been developed at LBNL, and lately in collaboration with SLAC, over the past 7 years. Possible remedies to mitigate the effect are also discussed. We have recently included the possibility to simulate different magnetic field configurations in our code including solenoid, quadrupole, sextupole and wiggler.

  3. Recent electron-cloud simulation results for the main damping rings of the NLC and TESLA linear colliders

    SciTech Connect

    Pivi, M.; Raubenheimer, T.O.; Furman, M.A.

    2003-05-01

    In the beam pipe of the Main Damping Ring (MDR) of the Next Linear Collider (NLC), ionization of residual gases and secondary emission give rise to an electron-cloud which stabilizes to equilibrium after few bunch trains. In this paper, we present recent computer simulation results for the main features of the electron cloud at the NLC and preliminary simulation results for the TESLA main damping rings, obtained with the code POSINST that has been developed at LBNL, and lately in collaboration with SLAC, over the past 7 years. Possible remedies to mitigate the effect are also discussed. We have recently included the possibility to simulate different magnetic field configurations in our code including solenoid, quadrupole, sextupole and wiggler.

  4. Proton MRS of the unilateral substantia nigra in the human brain at 4 tesla: detection of high GABA concentrations.

    PubMed

    Oz, Gülin; Terpstra, Melissa; Tkác, Ivan; Aia, Pratibha; Lowary, Jodi; Tuite, Paul J; Gruetter, Rolf

    2006-02-01

    Parkinson's disease (PD) is characterized by loss of dopaminergic neurons in the substantia nigra (SN), the cause of which is unknown. Characterization of early SN pathology could prove beneficial in the treatment and diagnosis of PD. The present study shows that with the use of short-echo (5 ms) Stimulated-Echo Acquisition Mode (STEAM) spectroscopy and LCModel, a neurochemical profile consisting of 10 metabolites, including gamma-aminobutyric acid (GABA), glutamate (Glu), and glutathione (GSH), can be measured from the unilateral SN at 4 tesla. The neurochemical profile of the SN is unique and characterized by a fourfold higher GABA/Glu ratio compared to the cortex, in excellent agreement with established neurochemistry. The presence of elevated GABA levels in SN was validated with the use of editing, suggesting that partial volume effects were greatly reduced. These findings establish the feasibility of obtaining a neurochemical profile of the unilateral human SN by single-voxel spectroscopy in small volumes.

  5. Subglacial Silicic Eruptions: Wet Cavities and Moist Cavities.

    NASA Astrophysics Data System (ADS)

    Stevenson, J. A.; McGarvie, D. W.; Gilbert, J. S.; Smellie, J. L.

    2007-05-01

    ice produces water, however in the Kerlingarfjöll eruption (which is thought to have been relatively brief and the vesicular magma is likely to have contained less heat per unit volume) the volumes were small and the subglacial cavity could be appropriately described as 'moist'. The Prestahnúkur eruption occurred in a 'wet' cavity but 'lacustrine' conditions were never developed and the ice was always close to the edifice. Poor sorting and structure in the subglacial deposits are due to a lack of time and space for sorting to occur. In contrast to more mafic eruptions, which are characterised by very strong meltwater-ice interactions, the main influence of the ice during subglacial rhyolite eruptions is reflected in the confinement of eruptive products.

  6. Mechanical failure of cavities in poroelastic media

    SciTech Connect

    Ozkan, G.; Ortoleva, P.

    1998-12-31

    The stress-induced failure of cavities in poroelastic media is investigated using an analytical solution of the elastic matrix inclusion problem of Eshelby and a rock failure criterion. The elastic properties of the porous matrix surrounding the cavity are modeled using a self-consistent version of the theory of Berryman while the cavity collapse criterion is based on a failure condition calibrated as a function of matrix mineralogy, grain size and porosity. The influence of the latter textural variables as well as pore fluid pressure and cavity shape and orientation relative to the far-field stress are evaluated. The region of failure on the cavity surface is identified. These results are applied to the prediction of vug stability in a sedimentary basin in the context of vuggy reservoir exploration and production.

  7. Air flow in a collapsing cavity

    NASA Astrophysics Data System (ADS)

    Peters, Ivo R.; Gekle, Stephan; Lohse, Detlef; van der Meer, Devaraj

    2013-03-01

    We experimentally study the airflow in a collapsing cavity created by the impact of a circular disc 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.

  8. Cavity cooling below the recoil limit.

    PubMed

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

    2012-07-06

    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.

  9. Automated Hydroforming of Seamless Superconducting RF Cavity

    SciTech Connect

    Nagata, Tomohiko; Shinozawa, Seiichi; Abe, Noriyuki; Nagakubo, Junki; Murakami, Hirohiko; Tajima, Tsuyoshi; Inoue, Hitoshi; Yamanaka, Masashi; Ueno, Kenji

    2012-07-31

    We are studying the possibility of automated hydroforming process for seamless superconducting RF cavities. Preliminary hydroforming tests of three-cell cavities from seamless tubes made of C1020 copper have been performed. The key point of an automated forming is to monitor and strictly control some parameters such as operation time, internal pressure and material displacements. Especially, it is necessary for our studies to be able to control axial and radial deformation independently. We plan to perform the forming in two stages to increase the reliability of successful forming. In the first stage hydroforming by using intermediate constraint dies, three-cell cavities were successfully formed in less than 1 minute. In parallel, we did elongation tests on cavity-quality niobium and confirmed that it is possible to achieve an elongation of >64% in 2 stages that is required for our forming of 1.3 GHz cavities.

  10. Fast thermometry for superconducting rf cavity testing

    SciTech Connect

    Orris, Darryl; Bellantoni, Leo; Carcagno, Ruben H.; Edwards, Helen; Harms, Elvin Robert; Khabiboulline, Timergali N.; Kotelnikov, Sergey; Makulski, Andrzej; Nehring, Roger; Pischalnikov, Yuriy; /Fermilab

    2007-06-01

    Fast readout of strategically placed low heat capacity thermometry can provide valuable information of Superconducting RF (SRF) cavity performance. Such a system has proven very effective for the development and testing of new cavity designs. Recently, several resistance temperature detectors (RTDs) were installed in key regions of interest on a new 9 cell 3.9 GHz SRF cavity with integrated HOM design at FNAL. A data acquisition system was developed to read out these sensors with enough time and temperature resolution to measure temperature changes on the cavity due to heat generated from multipacting or quenching within power pulses. The design and performance of the fast thermometry system will be discussed along with results from tests of the 9 cell 3.9GHz SRF cavity.

  11. Casimir forces of metallic microstructures into cavities

    NASA Astrophysics Data System (ADS)

    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.

  12. Interaction of copper with cavities in silicon

    NASA Astrophysics Data System (ADS)

    Myers, S. M.; Follstaedt, D. M.

    1996-02-01

    Copper in Si was shown to be strongly bound at cavities formed by He ion implantation and annealing. Evolution of this system during heating was observed by Rutherford backscattering spectrometry and transmission electron microscopy. Results were mathematically modeled to characterize quantitatively the binding of Cu in the cavities and, for comparison, in precipitates of the equilibrium silicide, η-Cu3Si. Binding of Cu to cavities occurred by chemisorption on the walls, and the binding energy was determined to be 2.2±0.2 eV relative to solution in Si. The heat of solution from the silicide was found to be 1.7 eV, consistent with the published phase diagram. These findings suggest the use of cavities for metal-impurity gettering in Si devices. Hydrogen in solution in equilibrium with external H2 gas displaced Cu atoms from cavity walls, a mechanistically illuminating effect that is also of practical concern for gettering applications.

  13. Optomechanical photon shuttling between photonic cavities.

    PubMed

    Li, Huan; Li, Mo

    2014-11-01

    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 non-local effects on propagating optical fields or multiple localized optical modes at distances. Here, we demonstrate a multicavity optomechanical device 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 this 'photon see-saw', are modulated antisymmetrically 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 empty cavity during every oscillation cycle in a well-regulated fashion.

  14. Vertical-Cavity Surface-Emitting Lasers

    NASA Astrophysics Data System (ADS)

    Wilmsen, Carl W.; Temkin, Henryk; Coldren, Larry A.

    2002-01-01

    1. Introduction to VCSELs L. A. Coldren, C. W. Wilmsen and H. Temkin; 2. Fundamental issues in VCSEL design L. A. Coldren and Eric R. Hegblom; 3. Enhancement of spontaneous emission in microcavities E. F. Schubert and N. E. J. Hunt; 4. Epitaxy of vertical-cavity lasers R. P. Schneider Jr and Y. H. Young; 5. Fabrication and performance of vertical-cavity surface-emitting lasers Kent D. Choquette and Kent Geib; 6. Polarization related properties of vertical cavity lasers Dmitri Kuksenkov and Henryk Temkin; 7. Visible light emitting vertical cavity lasers Robert L. Thornton; 8. Long-wavelength vertical-cavity lasers Dubrakovo I. Babic, Joachim Piprek and John E. Bowers; 9. Overview of VCSEL applications Richard C. Williamson; 10. Optical interconnection applications and required characteristics Kenichi Kasahara; 11. VCSEL-based fiber-optic data communications Kenneth Hahn and Kirk Giboney; 12. VCSEL-based smart pixels for free space optoelectronic processing C. W. Wilmsen.

  15. Microphonics Measurements in SRF Cavities for RIA

    SciTech Connect

    Kelly, M.P.; Fuerst, Joel; Kedzie, M.; Sharamentov, S.I.; Shepard, Kenneth; Delayen, Jean

    2003-05-01

    Phase stabilization of the RIA drift tube cavities in the presence of microphonics will be a key issue for RIA. Due to the relatively low beam currents (lte 0.5 pmA) required for the RIA driver, microphonics will impact the rf power required to control the cavity fields. Microphonics measurements on the ANL Beta=0.4 single spoke cavity and on the ANL Beta=0.4 two-cell spoke cavity have been performed many at high fields and using a new "cavity resonance monitor" device developed in collaboration with JLAB. Tests on a cold two-cell spoke are the first ever on a multi-cell spoke geometry. The design is essentially a production model with an integral stainless steel housing to hold the liquid helium bath.

  16. A six-channel pediatric coil array for detection of children spinal pathologies by MRI at 1.5 Tesla

    SciTech Connect

    López Terrones, Marcos Alonso; Solís-Nájera, Sergio Enrique

    2014-11-07

    Nowadays, magnetic resonance (MR) in Mexico has become a standard technique for clinical imaging. Although most of the times the MR systems contain only coils oriented for adults. Radiologists use these coils for children studies due to the non-availability of pediatric coils. Image quality is decreased due to the low signal to noise ratio delivered to the system. The development of RF coils is always focused towards increasing SNR and optimizing the RF penetration into the sample. Moreover, spinal pathologies in children, which are an important topic in pediatric care, cover congenital and neuromuscular disorders that occur in childhood. In this work, the design of a dedicated six-channel coil for detection of spinal pathologies at 1.5 Tesla is addressed. Numerical electromagnetic simulations were performed in order to evaluate their magnetic field performance at (63.6 MHz) 1.5 Tesla. The magnetic field uniformity as well as the RF penetration depth of the coil configurations was evaluated in order to find the best/optimized coil array configuration. The coil is comprised of three rows, one with 4 coil elements and two with only one coil element. Phantom and in vivo images were acquired with the six-channel pediatric coil array. The phantom images agree with the simulated data. In vivo images acquired with the 6-channel pediatric coil array have shown very good penetration depth and homogeneity, which allow better image quality throughout the whole FOV. In addition, the parallel imaging capabilities of the array allow the acceleration of the experiments avoiding possible motion artifacts.

  17. Force and torque effects of a 1.5-Tesla MRI scanner on cardiac pacemakers and ICDs.

    PubMed

    Luechinger, R; Duru, F; Scheidegger, M B; Boesiger, P; Candinas, R

    2001-02-01

    Magnetic resonance imaging (MRI) is a widely accepted tool for the diagnosis of a variety of disease states. However, the presence of an implanted pacemaker is considered to be a strict contraindication to MRI in a vast majority of centers due to safety concerns. In phantom studies, the authors investigated the force and torque effects of the static magnetic field of MRI on pacemakers and ICDs. Thirty-one pacemakers (15 dual chamber and 16 single chamber units) from eight manufacturers and 13 ICDs from four manufacturers were exposed to the static magnetic field of a 1.5-Tesla MRI scanner. Magnetic force and acceleration measurements were obtained quantitatively, and torque measurements were made qualitatively. For pacemakers, the measured magnetic force was in the range of 0.05-3.60 N. Pacemakers released after 1995 had low magnetic force values as compared to the older devices. For these devices, the measured acceleration was even lower than the gravity of the earth (< 9.81 N/kg). Likewise, the torque levels were significantly reduced in newer generation pacemakers (< or = 2 from a scale of 6). ICD devices, except for one recent model, showed higher force (1.03-5.85 N), acceleration 9.5-34.2 N/kg), and torque (5-6 out of 6) levels. In conclusion, modern pacemakers present no safety risk with respect to magnetic force and torque induced by the static magnetic field of a 1.5-Tesla MRI scanner. However, ICD devices, despite considerable reduction in size and weight, may still pose problems due to strong magnetic force and torque.

  18. A six-channel pediatric coil array for detection of children spinal pathologies by MRI at 1.5 Tesla

    NASA Astrophysics Data System (ADS)

    López Terrones, Marcos Alonso; Solís-Nájera, Sergio Enrique

    2014-11-01

    Nowadays, magnetic resonance (MR) in Mexico has become a standard technique for clinical imaging. Although most of the times the MR systems contain only coils oriented for adults. Radiologists use these coils for children studies due to the non-availability of pediatric coils. Image quality is decreased due to the low signal to noise ratio delivered to the system. The development of RF coils is always focused towards increasing SNR and optimizing the RF penetration into the sample. Moreover, spinal pathologies in children, which are an important topic in pediatric care, cover congenital and neuromuscular disorders that occur in childhood. In this work, the design of a dedicated six-channel coil for detection of spinal pathologies at 1.5 Tesla is addressed. Numerical electromagnetic simulations were performed in order to evaluate their magnetic field performance at (63.6 MHz) 1.5 Tesla. The magnetic field uniformity as well as the RF penetration depth of the coil configurations was evaluated in order to find the best/optimized coil array configuration. The coil is comprised of three rows, one with 4 coil elements and two with only one coil element. Phantom and in vivo images were acquired with the six-channel pediatric coil array. The phantom images agree with the simulated data. In vivo images acquired with the 6-channel pediatric coil array have shown very good penetration depth and homogeneity, which allow better image quality throughout the whole FOV. In addition, the parallel imaging capabilities of the array allow the acceleration of the experiments avoiding possible motion artifacts.

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

    NASA Astrophysics Data System (ADS)

    Kozyreff, G.; Gelens, L.

    2011-08-01

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

  20. Resonant-cavity antenna for plasma heating

    SciTech Connect

    Perkins, F.W. Jr.; Chiu, S.C.; Rawls, J.M.

    1987-04-28

    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.

  1. Michelson-Morley with a Birefringent Cavity

    NASA Astrophysics Data System (ADS)

    Monsalve, Francisco J.; Hohensee, Michael; Müller, Holger

    2012-06-01

    We report on the progress of a birefringent cavity test of the isotropy of the speed of light. Previous experimental tests have constrained anisotropies in the speed of light at the level of parts in 10^17 [1-2]. These experiments search for frame-dependent variations in the resonant frequencies of two orthogonally mounted optical cavities. Uncorrelated fluctuations in the cavity lengths are a significant challenge for such experiments. Our experiment uses a single dielectric-filled cavity, and measures the difference in the resonant frequency of two orthogonally polarized modes. Anisotropies in the speed of light will manifest as a frame-dependent strain on the dielectric [3-4], giving rise to a frame-dependent variation in the cavity birefringence. By making the length of each cavity mode identical, we expect that our experiment will be less sensitive to thermal cavity fluctuations. [4pt] [1] S. Herrmann, A. Senger, K. M"ohle, M. Nagel, E.V. Kovalchuk and A. Peters, PRD 80, 105011 (2009).[2] Ch. Eisel, A. Yu. Nevsky, and S. Schiller, PRL 103, 090401 (2009).[3] H. M"uller, PRD 71, 045004 (2005).[4] V.A. Kosteleck'y and M. Mewes, PRD 80, 015020 (2009).

  2. Production of Seamless Superconducting Radio Frequency Cavities from Ultra-fine Grained Niobium, Phase II Final Report

    SciTech Connect

    Roy Crooks, Ph.D., P.E.

    2009-10-31

    The positron and electron linacs of the International Linear Collider (ILC) will require over 14,000, nine-cell, one meter length, superconducting radio frequency (SRF) cavities [ILC Reference Design Report, 2007]. Manufacturing on this scale will benefit from more efficient fabrication methods. The current methods of fabricating SRF cavities involve deep drawing of the halves of each of the elliptical cells and joining them by high-vacuum, electron beam welding, with at least 19 circumferential welds per cavity. The welding is costly and has undesirable effects on the cavity surfaces, including grain-scale surface roughening at the weld seams. Hydroforming of seamless tubes avoids welding, but hydroforming of coarse-grained seamless tubes results in strain-induced surface roughening. Surface roughness limits accelerating fields, because asperities prematurely exceed the critical magnetic field and become normal conducting. This project explored the technical and economic feasibility of an improved processing method for seamless tubes for hydroforming. Severe deformation of bulk material was first used to produce a fine structure, followed by extrusion and flow-forming methods of tube making. Extrusion of the randomly oriented, fine-grained bulk material proceeded under largely steady-state conditions, and resulted in a uniform structure, which was found to be finer and more crystallographically random than standard (high purity) RRR niobium sheet metal. A 165 mm diameter billet of RRR grade niobium was processed into five, 150 mm I.D. tubes, each over 1.8 m in length, to meet the dimensions used by the DESY ILC hydroforming machine. Mechanical properties met specifications. Costs of prototype tube production were approximately twice the price of RRR niobium sheet, and are expected to be comparable with economies of scale. Hydroforming and superconducting testing will be pursued in subsequent collaborations with DESY and Fermilab. SRF Cavities are used to construct

  3. Properties of Cusp Diamagnetic Cavities

    NASA Technical Reports Server (NTRS)

    Sheldon, Robert B.

    2003-01-01

    Progress can be reported in two areas related to characterizing the properties of cusp diamagnetic cavities. Laboratory terrella experiments have been conducted for the purpose of using neutral gas excitation as a tracer of trapped electron populations in the presence of two dipoles that are used to develop a magnetic cusp topology. Figure 1 and 2 show top and side views of two configurations. Dipole trapped electron populations appear as the two luminous annular rings. Other populations are the most intense regions are shown. Interspersed between these regions are narrow regions that represent the topological cusps in these configurations. That they contain luminous gas is evidence for cusp trapping similar to what we believe exists in the terrestrial magnetosphere. The asymmetry of these cusp regions as seen in Figure 1 is the result of a relative tilt between the two dipoles suggestive of what would be expected in space. It is in these regions that particle observations were sought, so as to validate the realization of proposed and laboratory achieved trapping in a diamagnetic cusp. Figure 3 shows particle trajectories in a modeled cusp magnetic topology for three particle energies. Blue, green, and red traces correspond to increasing energies. Due to factors discussed outside of this final report, a thorough exploration of relevant satellite observations have not been achieved.

  4. Demonstration of superconducting micromachined cavities

    SciTech Connect

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

    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.

  5. Polymer microlasers with a suspended cavity design

    NASA Astrophysics Data System (ADS)

    Vanga, Sudheer Kumar; Nalla, Venkatram; Bettiol, Andrew A.

    2015-04-01

    We report on the fabrication of microlasers with suspended cavity design in a thin layer of Rhodamine B doped SU-8 polymer using proton beam writing. Optical characterization of the fabricated three-dimensional microlasers under ambient atmosphere results in low lasing threshold of 0.5 μJ/mm2, which is an improvement by factor of 2 when compared to planar microlasers. The directional behavior is also observed in whispering gallery mode microlasers with spiral cavity design. These microlasers with suspended cavity design are not only useful in reducing the lasing threshold but also have significance in 3D photonic integrated circuits.

  6. Clamshell microwave cavities having a superconductive coating

    DOEpatents

    Cooke, D. Wayne; Arendt, Paul N.; Piel, Helmut

    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.

  7. Installation and Commissioning of a 6-Tesla Superconducting Wavelength Shifter at Taiwan Light Source

    NASA Astrophysics Data System (ADS)

    Chang, C. H.; Chang, H. P.; Chen, Jenny; Chen, J. R.; Fan, T. C.; Hwang, C. S.; Hsiung, G. Y.; Hsu, K. T.; Kuo, C. C.; Luo, G. H.; Wang, D. J.; Wang, M. H.

    2005-09-01

    The Taiwan Light Source (TLS) is the first third-generation light source in Asia. The storage ring has six straight sections one section for injection, one for the RF cavities and diagnostic instrumentation and four sections for insertion devices, which are U5, U9, EPU and W20. Generating high-energy X-ray photons is a high priority at TLS. A single hybrid type wiggler is associated with three beam lines to serve X-ray users. The installed Superconducting Wavelength Shifter (SWLS) is very compact in size and can produce very high-energy photons. The injection section at TLS can barely accommodate the SWLS. The expected multipole components of the SWLS are strong, shrink the dynamic aperture; perturb the beta function, and reduce the beam lifetime. The increase in the synchrotron radiation by the SWLS also changes beam emittance and increases the energy spread. The influence of SWLS on the low-energy, 1.5 GeV, storage-ring should not be neglected. The downstream kicker with the water-cooled copper mask must be modified to prevent a potential meltdown of the welding junction of the ceramic chamber because the heat load is high. The 1.2 μs half-sine pulse field of the kicker is then altered by the copper-made radiation mask, which is installed inside the ceramic chamber. The operating capability of cryogenic system is established to ensure the smooth commissioning of the SWLS. The magnetic field mapping, the dynamic aperture simulation data and commissioning results will be presented and discussed herein.

  8. Atomic hydrogen maser active oscillator cavity and bulb design optimization

    NASA Technical Reports Server (NTRS)

    Peters, H. E.; Washburn, P. J.

    1984-01-01

    The performance characteristics and reliability of the active oscillator atomic hydrogen maser depend upon oscillation parameters which characterize the interaction region of the maser, the resonant cavity and atom storage bulb assembly. With particular attention to use of the cavity frequency switching servo (1) to reduce cavity pulling, it is important to maintain high oscillation level, high atomic beam flux utilization efficiency, small spin exchange parameter and high cavity quality factor. It is also desirable to have a small and rigid cavity and bulb structure and to minimize the cavity temperature sensitivity. Curves for a novel hydrogen maser cavity configuration which is partially loaded with a quartz dielectric cylinder and show the relationships between cavity length, cavity diameter, bulb size, dielectric thickness, cavity quality factor, filling factor and cavity frequency temperature coefficient are presented. The results are discussed in terms of improvement in maser performance resulting from particular design choices.

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

    SciTech Connect

    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

  10. Frequency combs for cavity cascades: OPO combs and graphene-coupled cavities

    NASA Astrophysics Data System (ADS)

    Lee, Kevin F.; Kowzan, Grzegorz; Lee, C.-C.; Mohr, C.; Jiang, Jie; Schunemann, Peter G.; Schibli, T. R.; Maslowski, Piotr; Fermann, M. E.

    2017-01-01

    Frequency combs can be used directly, for example as a highly precise spectroscopic light source. They can also be used indirectly, as a bridge between devices whose high precision requirements would normally make them incompatible. Here, we demonstrate two ways that a frequency comb enables new technologies by matching optical cavities. One cavity is the laser oscillator. A second cavity is a low-threshold doubly-resonant optical parametric oscillator (OPO). Extending optical referencing to the doubly-resonant OPO turns the otherwise unstable device into an extremely precise midinfrared frequency comb. Another cavity is an optical enhancement cavity for amplifying spectral absorption in a gas. With the high speed of a graphene-modulated frequency comb, we can couple a frequency comb directly into a high-finesse cavity for trace gas detection.

  11. Fabrication of a centimeter-long cavity on a nanofiber for cavity quantum electrodynamics

    NASA Astrophysics Data System (ADS)

    Keloth, Jameesh; Nayak, K. P.; Hakuta, K.

    2017-03-01

    We report the fabrication of a 1.2 cm long cavity directly on a nanofiber using femtosecond laser ablation. The cavity modes with finesse value in the range 200-400 can still maintain the transmission between 40-60%, which can enable "strong-coupling" regime of cavity QED for a single atom trapped 200 nm away from the fiber surface. For such cavity modes, we estimate the one-pass intra-cavity transmission to be 99.53%. Other cavity modes, which can enable high cooperativity in the range 3-10, show transmission over 60-85% and are suitable for fiber-based single photon sources and quantum nonlinear optics in the "Purcell" regime.

  12. Deflecting light into resonant cavities for spectroscopy

    DOEpatents

    Zare, Richard N.; Martin, Juergen; Paldus, Barbara A.

    1998-01-01

    Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available.

  13. Deflecting light into resonant cavities for spectroscopy

    DOEpatents

    Zare, R.N.; Martin, J.; Paldus, B.A.

    1998-09-29

    Light is coupled into a cavity ring down spectroscopy (CRDS) resonant cavity using an acousto-optic modulator. The AOM allows in-coupling efficiencies in excess of 40%, which is two to three orders of magnitude higher than in conventional systems using a cavity mirror for in-coupling. The AOM shutoff time is shorter than the roundtrip time of the cavity. The higher light intensities lead to a reduction in shot noise, and allow the use of relatively insensitive but fast-responding detectors such as photovoltaic detectors. Other deflection devices such as electro-optic modulators or elements used in conventional Q-switching may be used instead of the AOM. The method is particularly useful in the mid-infrared, far-infrared, and ultraviolet wavelength ranges, for which moderately reflecting input mirrors are not widely available. 5 figs.

  14. Constant field gradient planar coupled cavity structure

    DOEpatents

    Kang, Yoon W.; Kustom, Robert L.

    1999-01-01

    A cavity structure having at least two opposing planar housing members spaced apart to accommodate the passage of a particle beam through the structure between the members. Each of the housing members have a plurality of serially aligned hollows defined therein, and also passages, formed in the members, which interconnect serially adjacent hollows to provide communication between the hollows. The opposing planar housing members are spaced and aligned such that the hollows in one member cooperate with corresponding hollows in the other member to form a plurality of resonant cavities aligned along the particle beam within the cavity structure. To facilitate the obtaining of a constant field gradient within the cavity structure, the passages are configured so as to be incrementally narrower in the direction of travel of the particle beam. In addition, the spacing distance between the opposing housing members is configured to be incrementally smaller in the direction of travel of the beam.

  15. Constant field gradient planar coupled cavity structure

    DOEpatents

    Kang, Y.W.; Kustom, R.L.

    1999-07-27

    A cavity structure is disclosed having at least two opposing planar housing members spaced apart to accommodate the passage of a particle beam through the structure between the members. Each of the housing members have a plurality of serially aligned hollows defined therein, and also passages, formed in the members, which interconnect serially adjacent hollows to provide communication between the hollows. The opposing planar housing members are spaced and aligned such that the hollows in one member cooperate with corresponding hollows in the other member to form a plurality of resonant cavities aligned along the particle beam within the cavity structure. To facilitate the obtaining of a constant field gradient within the cavity structure, the passages are configured so as to be incrementally narrower in the direction of travel of the particle beam. In addition, the spacing distance between the opposing housing members is configured to be incrementally smaller in the direction of travel of the beam. 16 figs.

  16. Degreasing and cleaning superconducting RF Niobium cavities

    SciTech Connect

    Rauchmiller, Michael; Kellett, Ron; /Fermilab

    2011-09-01

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

  17. Maser cavity servo-tuning system

    NASA Technical Reports Server (NTRS)

    Sydnor, R. L. (Inventor)

    1985-01-01

    Two collocated, weakly coupled probes, one loop and one dipole, detect the magnetic and electric fields inside a maser cavity. Signals from the probes are compared in phase, and the signal output from the phase detector is applied to a varactor, the reactance of which is coupled into the cavity by a microwave coupler. Alternatively, the varactor may be placed inside the cavity. Any deviation of phase from 90 deg as detected by the phase detector will then produce an error signal that will change the reactance coupled into the resonant cavity to change its reactance, and thus correct its resonance frequency. An alternative to using two probes is to use a single disk probe oriented to detect both the magnetic and electric fields, and thus provide the error signal directly.

  18. Nb3Sn for Radio Frequency Cavities

    SciTech Connect

    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.

  19. Interference and Chaos in Metamaterials Cavities

    NASA Astrophysics Data System (ADS)

    Litchinitser, Natalia; Jose, Jorge

    2014-03-01

    Optical metamaterials are engineered artificial nanostructures that possess optical properties not available in nature. As metamaterials research continues to mature, their practical applications as well as fundamental questions on wave propagation in these materials attract significant interest. In this talk we focus on wave propagation and interference in chaotic wave cavities with negative or near-zero index of refraction and in double-slit configurations. In this context, we explicitly consider an incomplete two-dimensional D-cavity previously studied, which shows chaotic ray propagation together with scars. We have addressed the question as to how that type of wave propagation is modified by adding metamaterials in these chaotic cavities. We find that the wave interference patterns show significant qualitatively and quantitative changes depending on the effective parameters of the cavity, illumination conditions (planes waves versus beams), and geometry of the system. We will discuss possible experimental setups where these results may be validated.

  20. Photonic crystal cavities with metallic Schottky contacts

    SciTech Connect

    Quiring, W.; Al-Hmoud, M.; Reuter, D.; Zrenner, A.; Rai, A.; Wieck, A. D.

    2015-07-27

    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.

  1. Wakefield Damping for the CLIC Crab Cavity

    SciTech Connect

    Ambattu, P.K.; Burt, G.; Dexter, A.C.; Carter, R.G.; Khan, V.; Jones, R.M.; 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. Selected computations of transonic cavity flows

    NASA Technical Reports Server (NTRS)

    Atwood, Christopher A.

    1993-01-01

    An efficient diagonal scheme implemented in an overset mesh framework has permitted the analysis of geometrically complex cavity flows via the Reynolds averaged Navier-Stokes equations. Use of rapid hyperbolic and algebraic grid methods has allowed simple specification of critical turbulent regions with an algebraic turbulence model. Comparisons between numerical and experimental results are made in two dimensions for the following problems: a backward-facing step; a resonating cavity; and two quieted cavity configurations. In three-dimensions the flow about three early concepts of the stratospheric Observatory For Infrared Astronomy (SOFIA) are compared to wind-tunnel data. Shedding frequencies of resolved shear layer structures are compared against experiment for the quieted cavities. The results demonstrate the progress of computational assessment of configuration safety and performance.

  3. Stability of proteins inside a hydrophobic cavity

    NASA Astrophysics Data System (ADS)

    Radhakrishna, Mithun; Sharma, Sumit; Kumar, Sanat K.

    2011-03-01

    Previous studies have shown that enclosing a protein in an athermal cavity stabilizes the protein against reversible unfolding by virtue of eliminating many open chain conformations. Examples of such confined spaces include pores in chromatographic columns, Anfinsen's cage in Chaperonins, interiors of Ribosomes or regions of steric occlusion inside cells. However, the situation is more complex inside a hydrophobic cavity. The protein has a tendency to adsorb on the surface of the hydrophobic cavity, but at the same time it loses conformational entropy because of confinement. We study this system using a simple Hydrophobic Polar (HP) lattice protein model. Canonical Monte Carlo (MC) simulations at different temperatures and surface hydrophobicity show that proteins are stabilized at low and moderate hydrophobicity upon adsorption. The range of surface hydrophobicity over which a protein is stable increases with a decrease in radius of the cavity.

  4. Two Dimensional Plasmonic Cavities on Moire Surfaces

    NASA Astrophysics Data System (ADS)

    Balci, Sinan; Kocabas, Askin; Karabiyik, Mustafa; Kocabas, Coskun; Aydinli, Atilla

    2010-03-01

    We investigate surface plasmon polariton (SPP) cavitiy modes on two dimensional Moire surfaces in the visible spectrum. Two dimensional hexagonal Moire surface can be recorded on a photoresist layer using Interference lithography (IL). Two sequential exposures at slightly different angles in IL generate one dimensional Moire surfaces. Further sequential exposure for the same sample at slightly different angles after turning the sample 60 degrees around its own axis generates two dimensional hexagonal Moire cavity. Spectroscopic reflection measurements have shown plasmonic band gaps and cavity states at all the azimuthal angles (omnidirectional cavity and band gap formation) investigated. The plasmonic band gap edge and the cavity states energies show six fold symmetry on the two dimensional Moire surface as measured in reflection measurements.

  5. Open safety pin in the nasal cavity.

    PubMed

    Sen, I; Sikder, B; Sinha, R; Paul, R

    2004-04-01

    Foreign bodies in the nasal cavity are common-day occurrences in Otolaryngologic practice. But an open safety pin in nose with it' s sharp end directed towards roof is a rare incidence, and available literature is silent about this presentation; it is probably, the first of it' s kind being reported. Two cases of safety pins inside the nasal cavity, one open and the other closed, have been presented here with a brief review of literature.

  6. Cellular automata in photonic cavity arrays.

    PubMed

    Li, Jing; Liew, T C H

    2016-10-31

    We propose theoretically a photonic Turing machine based on cellular automata in arrays of nonlinear cavities coupled with artificial gauge fields. The state of the system is recorded making use of the bistability of driven cavities, in which losses are fully compensated by an external continuous drive. The sequential update of the automaton layers is achieved automatically, by the local switching of bistable states, without requiring any additional synchronization or temporal control.

  7. Autoimmune Disease Manifestations in the Oral Cavity.

    PubMed

    Magliocca, Kelly R; Fitzpatrick, Sarah G

    2017-03-01

    Immune-related disorders of the oral cavity may occur as primary disease process, secondary to systemic disease or neoplasm, or as a reaction to medications and other agents. The entities represented within this group may vary significantly by severity, clinical presentation, microscopic presentation, and special testing results. The selected immune-related conditions of the oral cavity in this article are categorized and presented by their prototypical tissue reaction patterns: vesiculobullous, including acantholytic and subepithelial separation; psoriasiform; spongiotic; and lichenoid reaction patterns.

  8. Exploration of very high gradient cavities

    SciTech Connect

    Eremeev, Grigory

    2011-07-01

    Several of the 9-cell ILC cavities processed at Jlab within ongoing ILC R&D program have shown interesting behavior at high fields, such as mode mixing and sudden field emission turn-on during quench. Equipped with thermometry and oscillating superleak transducer (OST) system for quench detection, we couple our RF measurements with local dissipation measurements. In this contribution we report on our findings with high gradient SRF cavities.

  9. The comet Halley diamagnetic cavity boundary

    NASA Technical Reports Server (NTRS)

    Cravens, T. E.; Lindgren, C. J.; Puhl, P.

    1995-01-01

    The magnetometer onboard the Giotto spacecraft observed a diamagnetic cavity surrounding the nucleus of comet Halley. A narrow transition layer with enhanced plasma density is formed at this shock-like boundary as a flux of cometary ions flowing into it from within the cavity is removed by electron-ion recombination. We examine the structure of this layer using both a two-dimensional magnetohydrodynamical model and a one- dimensional hybrid code.

  10. Development of spoke cavities for RIA.

    SciTech Connect

    Shepard, K. W.; Kelly, M. P.; Fuerst, J.; Kedzie, M.; Conway, Z. A.; Physics

    2006-07-15

    This paper reports the development status of 345 MHz, 4 cm beam aperture, three-spoke-loaded, TEM-class superconducting cavities for particle velocities 0.4 < v/c < 0.8. Two prototype cavities have been operated cw at 4.2 K at accelerating gradients above 10 MV/m. Results of cold tests, including mechanical properties and microphonic behavior, are presented.

  11. Effect of Cavity QED on Entanglement

    NASA Astrophysics Data System (ADS)

    Rfifi, Saad; Siyouri, Fatimazahra

    2016-11-01

    We use a quantum electrodynamics model, to study the evolution of maximally entangled bipartite states (Bell states), as well as a maximally entangled tripartite states as a multipartite system. Furthermore, we study the entanglement behaviour of these output states in cavity QED as function of interaction time and the coupling strength. The present study discusses the separability and the entanglement limit of such states after interaction with a cavity QED.

  12. Cavity quantum electrodynamics on a nanofiber using a composite photonic crystal cavity.

    PubMed

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

    2014-10-03

    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. By 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.

  13. Scaled experiments of explosions in cavities

    DOE PAGES

    Grun, J.; Cranch, G. A.; Lunsford, R.; ...

    2016-05-11

    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 simulationsmore » show that shock pressuresmeasured 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. As a result, the applicability of this work to validating codes used to simulate full-scale cavityexplosions is discussed.« less

  14. Woodpecker cavity aeration: a predictive model.

    PubMed

    Ar, Amos; Barnea, Anat; Yom-Tov, Yoram; Mersten-Katz, Cynthia

    2004-12-15

    We studied characteristics of the Syrian woodpecker (Dendrocopos syriacus) cavities in the field and a laboratory model, and rates of gas exchange in the laboratory. Night temperature of occupied cavities is 4.3 degrees C higher than empty ones, representing energy savings of approximately 24%. Oxygen conductance (GNO2) of an empty cavity is 7.1 ml[STPD] (Torr h)(-1), and is affected by winds at velocities up to 0.8 m/s. Day and night body temperatures were 42.0 and 40.1 degrees C, respectively. Steady-state O2 consumption rates (MO2) were 3.49 +/- 0.49 and 2.53 +/- 0.26 ml[STPD] (g h)(-1) during day and night respectively -- higher than predicted by allometry. A mathematical model describing PO2 in a cavity, taking into consideration MO2, GNO2, heat convection and wind speed, from the moment birds inhabit it, was developed. It shows that on the average, one woodpecker staying in its cavity at night does not encounter hypoxic conditions. However, in nest cavities with below the average GNO2, with more inhabitants (e.g. during the breeding season), hypoxia may become a problem.

  15. Transient Microphonic Effects In Superconducting Cavities

    SciTech Connect

    Thomas Powers; G. Davis; Lawrence King

    2005-07-10

    A number of experiments were performed on an installed and operational 5-cell CEBAF cavity to determine the minimum time required to reestablish stable gradient after a cavity window arc trip. Once it was determined that gradient could be reestablished within 10 ms by applying constant power RF signal in and a voltage controlled Oscillator-phase locked loop based system (VCO-PLL), a second experiment was performed to determine if stable gradient could be reestablished using a fixed frequency RF system with a simple gradient based closed loop control system. During this test, instabilities were observed in the cavity forward power signal, which were determined to be microphonic in nature. These microphonic effects were quantified using a cavity resonance monitor and a VCO{_}PLL RF system. Two types of microphonic effects were observed depending on the type of arc event. If the arc occurred in the vacuum space between the warm and cold windows, the transient frequency shift was about 75 Hz peak-to-peak. If the arc occurred on the cavity side of the cold window the transient frequency shift was about 400 Hz peak-to-peak. The background microphonics level for the tested cavity was approximately 30 Hz peak-to-peak. Experimental results, analysis of the resultant klystron power transients, the decay time of the transients, and the implications with respect to fast reset algorithms will be presented.

  16. "Fine grain Nb tube for SRF cavities"

    SciTech Connect

    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.

  17. Scaled experiments of explosions in cavities

    SciTech Connect

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

    2016-05-11

    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 pressuresmeasured 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. As a result, the applicability of this work to validating codes used to simulate full-scale cavityexplosions is discussed.

  18. Frequency doubled, cavity dumped feedback laser

    NASA Technical Reports Server (NTRS)

    Sipes, Jr., Donald L. (Inventor); Robinson, Deborah L. (Inventor)

    1989-01-01

    Higher efficiency in cavity dumping and frequency doubling in a laser used to produce modulated output beam pulses is achieved by deflecting light out of the resonant cavity to a third mirror through a frequency doubler using an electro-optic modulator and a polarizing beamsplitter in the resonant cavity, or using just an acousto-optic modulator to deflect light out of the laser cavity in response to a control signal (electric or acoustic). The frequency doubler in front of the third mirror rotates the frequency doubled light so that it will pass out of the laser cavity through the polarizing beamsplitter, while undoubled frequency light is reflected by the polarizing beamsplitter back into the gain medium of the laser. In the case of using a type-II frequency doubler, a dichroic beamsplitter deflects out the frequency doubled light and passes the undoubled frequency light to the polarizing beamsplitter for return to the laser gain medium. If an acousto-optic modulator is used, it deflects light out of the primary laser cavity, so a polarizing beamsplitter is not needed, and only a dichroic beamsplitter is needed to separate frequency doubled light out of the path from the third mirror.

  19. Parametric resonance in tunable superconducting cavities

    NASA Astrophysics Data System (ADS)

    Wustmann, Waltraut; Shumeiko, Vitaly

    2013-05-01

    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 radiation. We investigate the phase-sensitive amplification of external signals on resonance, as well as amplification of detuned signals, and relate the amplifier performance to that of linear parametric amplifiers. We also discuss applications of the device for dispersive qubit readout. Beyond the classical response of the cavity, we investigate small quantum fluctuations around the amplified classical signals. We evaluate the noise power spectrum both for the internal field in the cavity and the output field. Other quantum-statistical properties of the noise are addressed such as squeezing spectra, second-order coherence, and two-mode entanglement.

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

    PubMed Central

    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

  1. The fluid dynamics of work transfer in the non-uniform viscous rotating flow within a Tesla disc turbomachine

    NASA Astrophysics Data System (ADS)

    Guha, Abhijit; Sengupta, Sayantan

    2014-03-01

    In this article, the fluid dynamics of work transfer within the narrow spacing (usually of the order of 100 μm) of multiple concentric discs of a Tesla disc turbomachine (turbine or compressor) has been analysed theoretically and computationally. Both the overall work transfer and its spatial development have been considered. It has been established that the work transfer mechanism in a Tesla disc turbomachine is very different from that in a conventional turbomachine, and the formulation of the Euler's work equation for the disc turbomachine contains several conceptual subtleties because of the existence of complex, three dimensional, non-uniform, viscous flow features. A work equivalence principle has been enunciated, which establishes the equality between the magnitudes of work transfer determined rigorously from two different approaches—one based on the shear stress acting on the disc surfaces and the other based on the change in angular momentum of the fluid. Care is needed in identifying the shear stress components that are responsible for the generation or absorption of useful power. It is shown from the Reynolds transport theorem that mass-flow-averaged tangential velocities (as opposed to the normally used area-averaged values) must be used in determining the change in angular momentum; the calculation has to be carefully formulated since both radial velocity (that determines throughput) and tangential velocity (that generates torque) depend strongly on the coordinate perpendicular to the disc surfaces. The principle of work transfer has been examined both in the absolute and relative frames of reference, revealing the subtle role played by Coriolis force. The concept of a new non-dimensional quantity called the torque potential fraction (Δ tilde H) is introduced. The value of Δ tilde H at any radial position increases with a decrease in inter-disc spacing. The computational fluid dynamic analysis shows that, for small value of inter-disc spacing and

  2. Dynamic Multi-Coil Technique (DYNAMITE) Shimming for Echo-Planar Imaging of the Human Brain at 7 Tesla

    PubMed Central

    Juchem, Christoph; Rudrapatna, S. Umesh; Nixon, Terence W.; de Graaf, Robin A.

    2014-01-01

    Gradient-echo echo-planar imaging (EPI) is the primary method of choice in functional MRI and other methods relying on fast MRI to image brain activation and connectivity. However, the high susceptibility of EPI towards B0 magnetic field inhomogeneity poses serious challenges. Conventional magnetic field shimming with low-order spherical harmonic (SH) functions is capable of compensating shallow field distortions, but performs poorly for global brain shimming or on specific areas with strong susceptibility-induced B0 distortions such as the prefrontal cortex (PFC). Excellent B0 homogeneity has been demonstrated recently in the human brain at 7 Tesla with the DYNAmic Multi-coIl TEchnique (DYNAMITE) for magnetic field shimming (Juchem et al., J Magn Reson (2011) 212:280-288). Here, we report the benefits of DYNAMITE shimming for multi-slice EPI and T2* mapping. A standard deviation of 13 Hz was achieved for the residual B0 distribution in the human brain at 7 Tesla with DYNAMITE shimming and was 60% lower compared to conventional shimming that employs static zero through third order SH shapes. The residual field inhomogeneity with SH shimming led to an average 8 mm shift at acquisition parameters commonly used for fMRI and was reduced to 1.5-3 mm with DYNAMITE shimming. T2* values obtained from the prefrontal and temporal cortices with DYNAMITE shimming were 10-50% longer than those measured with SH shimming. The reduction of the confounding macroscopic B0 field gradients with DYNAMITE shimming thereby promises improved access to the relevant microscopic T2* effects. The combination of high spatial resolution and DYNAMITE shimming allows largely artifact-free EPI and T2* mapping throughout the brain, including prefrontal and temporal lobe areas. DYNAMITE shimming is expected to critically benefit a wide range of MRI applications that rely on excellent B0 magnetic field conditions including EPI-based fMRI to study various cognitive processes and assessing large

  3. Analysis of the Tesla transformer operation at the first half-wave of the output voltage taking into account ohmic losses

    NASA Astrophysics Data System (ADS)

    Palchikov, E. I.; Ryabchun, A. M.

    2016-06-01

    The speed and efficiency of the Tesla transformer at the first half-wave of the output voltage are studied as a function of the Q factors of the circuits and their coupling factor. Calculated results and experimental data are considered. It is shown that for given Q factors, there is an optimal value of the coupling factor providing the highest efficiency, which can be calculated and for which designers should work.

  4. Compound parabolic concentrator with cavity for tubular absorbers

    DOEpatents

    Winston, Roland

    1983-01-01

    A compond parabolic concentrator with a V-shaped cavity is provided in which an optical receiver is emplaced. The cavity redirects all energy entering between the receiver and the cavity structure onto the receiver, if the optical receiver is emplaced a distance from the cavity not greater than 0.27 r (where r is the radius of the receiver).

  5. Teleportation of a Weak Coherent Cavity Field State

    NASA Astrophysics Data System (ADS)

    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. In vivo functional connectome of human brainstem nuclei of the ascending arousal, autonomic and motor systems by high spatial resolution 7 Tesla fMRI

    PubMed Central

    Bianciardi, Marta; Toschi, Nicola; Eichner, Cornelius; Polimeni, Jonathan R.; Setsompop, Kawin; Brown, Emery N.; Hamalainen, Matti S.; Rosen, Bruce R.; Wald, Lawrence L.

    2016-01-01

    Object To map the in vivo human functional connectivity of several brainstem nuclei with the rest of the brain by using seed-based correlation of ultra-high magnetic field functional magnetic resonance imaging (fMRI) data. Materials and Methods We used the recently developed template of 11 brainstem nuclei derived from multi-contrast structural MRI at 7 Tesla as seed regions to determine their connectivity to the rest of the brain. To achieve this, we utilized the increased contrast-to-noise ratio of 7 Tesla fMRI compared to 3 Tesla and the time efficient simultaneous multi-slice imaging to cover the brain with high spatial resolution (1.1 mm-isotropic nominal resolution) while maintaining a short repetition time (2.5 s). Results The delineated Pearson’s correlation-based functional connectivity diagrams (connectomes) of 11 brainstem nuclei of the ascending arousal, motor and autonomic systems from 12 controls are presented and discussed in the context of existing histology and animal work. Conclusion Considering that the investigated brainstem nuclei play a crucial role in several vital functions, the delineated preliminary connectomes might prove useful for future in vivo research and clinical studies of human brainstem function and pathology, including disorders of consciousness, sleep disorders, autonomic disorders, Parkinson’s disease and other motor disorders. PMID:27126248

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

    SciTech Connect

    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.

  8. Radiation measurements during cavities conditioning on APS RF test stand

    SciTech Connect

    Grudzien, D.M.; Kustom, R.L.; Moe, H.J.; Song, J.J.

    1993-07-01

    In order to determine the shielding structure around the Advanced Photon Source (APS) synchrotron and storage ring RF stations, the X-ray radiation has been measured in the near field and far field regions of the RF cavities during the normal conditioning process. Two cavity types, a prototype 352-MHz single-cell cavity and a 352-MHz five-cell cavity, are used on the APS and are conditioned in the RF test stand. Vacuum measurements are also taken on a prototype 352-MHz single-cell cavity and a 352-MHz five-cell cavity. The data will be compared with data on the five-cell cavities from CERN.

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

    SciTech Connect

    Shepard, K. W.; Kelly, M. P.; Fuerst, J. D.

    2002-09-23

    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, {beta}{sub GEOM} = 0.15 quarter-wave resonant (QWR) cavity, and a 173 MHz, {beta}{sub GEOM} = 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.

  10. RF BREAKDOWN STUDIES USING PRESSURIZED CAVITIES

    SciTech Connect

    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

  11. Beam loading in magnicon deflection cavities

    SciTech Connect

    Hafizi, B.; Gold, S.H.

    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.

  12. Generating Long Scale-Length Plasma Jets Embedded in a Uniform, Multi-Tesla Magnetic-Field

    NASA Astrophysics Data System (ADS)

    Manuel, Mario; Kuranz, Carolyn; Rasmus, Alex; Klein, Sallee; Fein, Jeff; Belancourt, Patrick; Drake, R. P.; Pollock, Brad; Hazi, Andrew; Park, Jaebum; Williams, Jackson; Chen, Hui

    2013-10-01

    Collimated plasma jets emerge in many classes of astrophysical objects and are of great interest to explore in the laboratory. In many cases, these astrophysical jets exist within a background magnetic field where the magnetic pressure approaches the plasma pressure. Recent experiments performed at the Jupiter Laser Facility utilized a custom-designed solenoid to generate the multi-tesla fields necessary to achieve proper magnetization of the plasma. Time-gated interferometry, Schlieren imaging, and proton radiography were used to characterize jet evolution and collimation under varying degrees of magnetization. Experimental results will be presented and discussed. This work is funded by the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant number DE-NA0001840, by the National Laser User Facility Program, grant number DE-NA0000850, by the Predictive Sciences Academic Alliances Program in NNSA-ASC, grant number DEFC52-08NA28616, and by NASA through Einstein Postdoctoral Fellowship grant number PF3-140111 awarded by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for NASA under contract NAS8-03060.

  13. Improving heat generation of magnetic nanoparticles by pre-orientation of particles in a static three tesla magnetic field

    NASA Astrophysics Data System (ADS)

    Beck, Mathias M.; Lammel, Christian; Gleich, Bernhard

    2017-04-01

    Inductive heating of electrically insulating materials like fiberglass reinforced thermoplastics (FRTP) without susceptors is not possible. However, due to their low thermal conductivity a volumetric heat generation method is advisable to reach short heating times to melt this material for reshaping. This can be done with magnetic nanoparticles as susceptors within the thermoplastic of the FRTP using Néel relaxation. During the heating process the particle's magnetic moment rotates with the field while the particle itself is fixed within the thermoplastic. Therefore the heat dissipation of each particle depends on its orientation within the field. To achieve the maximum heat generation of the particles we pre-oriented the particles within a plastic at the best angle to the applied AC field for induction. To do this, five mass percent nanoparticles were dispersed in an epoxy resin, which was then hardened at room temperature in a static three Tesla magnetic field. After its solidification the heating behavior of the sample was compared to a reference sample, which was hardened without a field. The oriented particles showed an increased heating rate when oriented parallel to the applied AC field. The absorption rate was 3.3 times as high as the undirected reference sample. When the alternating electromagnetic field was perpendicular to the oriented particles, the specific absorption rate was similar to that of the reference sample. We compare this result with theory and with calculations from literature, and conduct a numerical simulation.

  14. A high-resolution 7-Tesla fMRI dataset from complex natural stimulation with an audio movie

    PubMed Central

    Hanke, Michael; Baumgartner, Florian J.; Ibe, Pierre; Kaule, Falko R.; Pollmann, Stefan; Speck, Oliver; Zinke, Wolf; Stadler, Jörg

    2014-01-01

    Here we present a high-resolution functional magnetic resonance (fMRI) dataset – 20 participants recorded at high field strength (7 Tesla) during prolonged stimulation with an auditory feature film (“Forrest Gump”). In addition, a comprehensive set of auxiliary data (T1w, T2w, DTI, susceptibility-weighted image, angiography) as well as measurements to assess technical and physiological noise components have been acquired. An initial analysis confirms that these data can be used to study common and idiosyncratic brain response patterns to complex auditory stimulation. Among the potential uses of this dataset are the study of auditory attention and cognition, language and music perception, and social perception. The auxiliary measurements enable a large variety of additional analysis strategies that relate functional response patterns to structural properties of the brain. Alongside the acquired data, we provide source code and detailed information on all employed procedures – from stimulus creation to data analysis. In order to facilitate replicative and derived works, only free and open-source software was utilized. PMID:25977761

  15. iTesla Power Systems Library (iPSL): A Modelica library for phasor time-domain simulations

    NASA Astrophysics Data System (ADS)

    Vanfretti, L.; Rabuzin, T.; Baudette, M.; Murad, M.

    The iTesla Power Systems Library (iPSL) is a Modelica package providing a set of power system components for phasor time-domain modeling and simulation. The Modelica language provides a systematic approach to develop models using a formal mathematical description, that uniquely specifies the physical behavior of a component or the entire system. Furthermore, the standardized specification of the Modelica language (Modelica Association [1]) enables unambiguous model exchange by allowing any Modelica-compliant tool to utilize the models for simulation and their analyses without the need of a specific model transformation tool. As the Modelica language is being developed with open specifications, any tool that implements these requirements can be utilized. This gives users the freedom of choosing an Integrated Development Environment (IDE) of their choice. Furthermore, any integration solver can be implemented within a Modelica tool to simulate Modelica models. Additionally, Modelica is an object-oriented language, enabling code factorization and model re-use to improve the readability of a library by structuring it with object-oriented hierarchy. The developed library is released under an open source license to enable a wider distribution and let the user customize it to their specific needs. This paper describes the iPSL and provides illustrative application examples.

  16. Improved fiber-optic link for the phase reference distribution system for the TESLA technology based projects

    NASA Astrophysics Data System (ADS)

    Czuba, Krzysztof; Felber, Matthias

    2005-09-01

    The UV Free-Electron Laser (UVFEL) [1], The X-Ray Free-Electron Laser (XFEL) [2] and The International Linear Accelerator (ILC) [9] projects will require phase synchronization of various RF frequency subsystems on kilometer distances with accuracy better than 1ps. To fulfill these requirements, a phase reference distribution system concept was proposed and a prototype was developed for tests in the TESLA Test Facility 2 (TTF2). An important part of the phase reference system is the fiber-optic phase stable, long distance link described in this paper. An interferometrical scheme with feedback on phase, suppressing long term phase drifts induced by temperature changes was developed and tested in laboratory and under accelerator conditions. A motorized optical delay line was used in the system to compensate for phase errors. Described are error considerations and most important project issues like the hardware development and the real time phase controller software. The presented measurement results satisfy the design requirements. Experience gained during the experiments yielded proposals for system improvements.

  17. In vivo high-resolution localized 1H MR spectroscopy in the awake rat brain at 7 Tesla

    PubMed Central

    Xu, Su; Ji, Yadong; Chen, Xi; Yang, Yihong; Gullapalli, Rao; Masri, Radi

    2012-01-01

    In vivo localized high-resolution 1H MR spectroscopy was performed in multiple brain regions without the use of anesthetic or paralytic agents in awake head-restrained rats that were previously trained in a simulated MRI environment using a 7 Tesla MR system. Spectra were obtained using a short echo time single-voxel point-resolved spectroscopy technique with voxel size ranging from 27–32.4 mm3 in the regions of anterior cingulate cortex, somatosensory cortex, hippocampus, and thalamus. Quantifiable spectra, without the need for any additional post-processing to correct for possible motion were reliably detected including the metabolites of interest such as γ-aminobutyric acid, glutamine, glutamate, myo-inositol, N-acetylaspartate, taurine, glycerophosphorylcholine/phosphorylcholine, creatine/phosphocreatine, and N-acetylaspartate/N-acetylaspartylglutamate. The spectral quality was comparable to spectra from anesthetized animals with sufficient spectral dispersion to separate metabolites such as glutamine and glutamate. Results from this study suggest that reliable information on major metabolites can be obtained without the confounding effects of anesthesia or paralytic agents in rodents. PMID:22570299

  18. 1.5-Tesla Multiparametric-Magnetic Resonance Imaging for the detection of clinically significant prostate cancer

    PubMed Central

    POPITA, CRISTIAN; POPITA, ANCA RALUCA; SITAR-TAUT, ADELA; PETRUT, BOGDAN; FETICA, BOGDAN; COMAN, IOAN

    2017-01-01

    Background and aim Multiparametric-magnetic resonance imaging (mp-MRI) is the main imaging modality used for prostate cancer detection. The aim of this study is to evaluate the diagnostic performance of mp-MRI at 1.5-Tesla (1.5-T) for the detection of clinically significant prostate cancer. Methods In this ethical board approved prospective study, 39 patients with suspected prostate cancer were included. Patients with a history of positive prostate biopsy and patients treated for prostate cancer were excluded. All patients were examined at 1.5-T MRI, before standard transrectal ultrasonography–guided biopsy. Results The overall sensitivity, specificity, positive predictive value and negative predictive value for mp-MRI were 100%, 73.68%, 80% and 100%, respectively. Conclusion Our results showed that 1.5 T mp-MRI has a high sensitivity for detection of clinically significant prostate cancer and high negative predictive value in order to rule out significant disease. PMID:28246496

  19. High current superconductivity in FeSe0.5Te0.5-coated conductors at 30 tesla.

    PubMed

    Si, Weidong; Han, Su Jung; Shi, Xiaoya; Ehrlich, Steven N; Jaroszynski, J; Goyal, Amit; Li, Qiang

    2013-01-01

    Although high-temperature superconductor cuprates have been discovered for more than 25 years, superconductors for high-field application are still based on low-temperature superconductors, such as Nb(3)Sn. The high anisotropies, brittle textures and high manufacturing costs limit the applicability of the cuprates. Here we demonstrate that the iron superconductors, without most of the drawbacks of the cuprates, have a superior high-field performance over low-temperature superconductors at 4.2 K. With a CeO(2) buffer, critical current densities >10(6)  A cm(-2) were observed in iron-chalcogenide FeSe(0.5)Te(0.5) films grown on single-crystalline and coated conductor substrates. These films are capable of carrying critical current densities exceeding 10(5) A cm(-2) under 30 tesla magnetic fields, which are much higher than those of low-temperature superconductors. High critical current densities, low magnetic field anisotropies and relatively strong grain coupling make iron-chalcogenide-coated conductors particularly attractive for high-field applications at liquid helium temperatures.

  20. A Novel 9.4 Tesla FTICR Mass Spectrometer with Improved Sensitivity, Mass Resolution, and Mass Range

    NASA Astrophysics Data System (ADS)

    Kaiser, Nathan K.; Quinn, John P.; Blakney, Gregory T.; Hendrickson, Christopher L.; Marshall, Alan G.

    2011-08-01

    Fourier transform ion cyclotron resonance (FTICR) mass spectrometry provides unparalleled mass measurement accuracy and resolving power. However, propagation of the technique into new analytical fields requires continued advances in instrument speed and sensitivity. Here, we describe a substantial redesign of our custom-built 9.4 tesla FTICR mass spectrometer that improves sensitivity, acquisition speed, and provides an optimized platform for future instrumentation development. The instrument was designed around custom vacuum chambers for improved ion optical alignment, minimized distance from the external ion trap to magnetic field center, and high conductance for effective differential pumping. The length of the transfer optics is 30% shorter than the prior system, for reduced time-of-flight mass discrimination and increased ion transmission and trapping efficiency at the ICR cell. The ICR cell, electrical vacuum feedthroughs, and cabling have been improved to reduce the detection circuit capacitance (and improve detection sensitivity) 2-fold. The design simplifies access to the ICR cell, and the modular vacuum flange accommodates new ICR cell technology, including linearized excitation, high surface area detection, and tunable electrostatic trapping potential.

  1. Differences in Velopharyngeal Structure during Speech among Asians Revealed by 3-Tesla Magnetic Resonance Imaging Movie Mode

    PubMed Central

    Nunthayanon, Kulthida; Honda, Ei-ichi; Shimazaki, Kazuo; Ohmori, Hiroko; Inoue-Arai, Maristela Sayuri; Kurabayashi, Tohru; Ono, Takashi

    2015-01-01

    Objective. Different bony structures can affect the function of the velopharyngeal muscles. Asian populations differ morphologically, including the morphologies of their bony structures. The purpose of this study was to compare the velopharyngeal structures during speech in two Asian populations: Japanese and Thai. Methods. Ten healthy Japanese and Thai females (five each) were evaluated with a 3-Tesla (3 T) magnetic resonance imaging (MRI) scanner while they produced vowel-consonant-vowel syllable (/asa/). A gradient-echo sequence, fast low-angle shot with segmented cine and parallel imaging technique was used to obtain sagittal images of the velopharyngeal structures. Results. MRI was carried out in real time during speech production, allowing investigations of the time-to-time changes in the velopharyngeal structures. Thai subjects had a significantly longer hard palate and produced shorter consonant than Japanese subjects. The velum of the Thai participants showed significant thickening during consonant production and their retroglossal space was significantly wider at rest, whereas the dimensional change during task performance was similar in the two populations. Conclusions. The 3 T MRI movie method can be used to investigate velopharyngeal function and diagnose velopharyngeal insufficiency. The racial differences may include differences in skeletal patterns and soft-tissue morphology that result in functional differences for the affected structures. PMID:26273584

  2. Coupled-cavity QED using planar photonic crystals.

    PubMed

    Hughes, S

    2007-02-23

    We introduce a technique for controlling cavity QED by indirectly coupling two planar-photonic-crystal nanocavities through an integrated waveguide. Guided by an explicit analytical expression for the photon Green function, the resulting optical response of a single quantum dot, embedded in one of the cavities, is shown to be profoundly influenced by the distant cavity. The regimes of cavity QED, e.g., vacuum Rabi splitting, are made significantly easier and richer than with one cavity alone.

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

    NASA Astrophysics Data System (ADS)

    Valles, N.; Liepe, M.; Furuta, F.; Gi, M.; Gonnella, D.; He, Y.; Ho, K.; Hoffstaetter, G.; Klein, D. S.; O'Connell, T.; Posen, S.; Quigley, P.; Sears, J.; Stedman, G. Q.; Tigner, M.; Veshcherevich, V.

    2014-01-01

    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.

  4. Spin-cavity interactions between a quantum dot molecule and a photonic crystal cavity.

    PubMed

    Vora, Patrick M; Bracker, Allan S; Carter, Samuel G; Sweeney, Timothy M; Kim, Mijin; Kim, Chul Soo; Yang, Lily; Brereton, Peter G; Economou, Sophia E; Gammon, Daniel

    2015-07-17

    The integration of InAs/GaAs quantum dots into nanophotonic cavities has led to impressive demonstrations of cavity quantum electrodynamics. However, these demonstrations are primarily based on two-level excitonic systems. Efforts to couple long-lived quantum dot electron spin states with a cavity are only now succeeding. Here we report a two-spin-cavity system, achieved by embedding an InAs quantum dot molecule within a photonic crystal cavity. With this system we obtain a spin singlet-triplet Λ-system where the ground-state spin splitting exceeds the cavity linewidth by an order of magnitude. This allows us to observe cavity-stimulated Raman emission that is highly spin-selective. Moreover, we demonstrate the first cases of cavity-enhanced optical nonlinearities in a solid-state Λ-system. This provides an all-optical, local method to control the spin exchange splitting. Incorporation of a highly engineerable quantum dot molecule into the photonic crystal architecture advances prospects for a quantum network.

  5. Spin–cavity interactions between a quantum dot molecule and a photonic crystal cavity

    PubMed Central

    Vora, Patrick M.; Bracker, Allan S.; Carter, Samuel G.; Sweeney, Timothy M.; Kim, Mijin; Kim, Chul Soo; Yang, Lily; Brereton, Peter G.; Economou, Sophia E.; Gammon, Daniel

    2015-01-01

    The integration of InAs/GaAs quantum dots into nanophotonic cavities has led to impressive demonstrations of cavity quantum electrodynamics. However, these demonstrations are primarily based on two-level excitonic systems. Efforts to couple long-lived quantum dot electron spin states with a cavity are only now succeeding. Here we report a two-spin–cavity system, achieved by embedding an InAs quantum dot molecule within a photonic crystal cavity. With this system we obtain a spin singlet–triplet Λ-system where the ground-state spin splitting exceeds the cavity linewidth by an order of magnitude. This allows us to observe cavity-stimulated Raman emission that is highly spin-selective. Moreover, we demonstrate the first cases of cavity-enhanced optical nonlinearities in a solid-state Λ-system. This provides an all-optical, local method to control the spin exchange splitting. Incorporation of a highly engineerable quantum dot molecule into the photonic crystal architecture advances prospects for a quantum network. PMID:26184654

  6. Spin-cavity interactions between a quantum dot molecule and a photonic crystal cavity

    NASA Astrophysics Data System (ADS)

    Vora, Patrick M.; Bracker, Allan S.; Carter, Samuel G.; Sweeney, Timothy M.; Kim, Mijin; Kim, Chul Soo; Yang, Lily; Brereton, Peter G.; Economou, Sophia E.; Gammon, Daniel

    2015-07-01

    The integration of InAs/GaAs quantum dots into nanophotonic cavities has led to impressive demonstrations of cavity quantum electrodynamics. However, these demonstrations are primarily based on two-level excitonic systems. Efforts to couple long-lived quantum dot electron spin states with a cavity are only now succeeding. Here we report a two-spin-cavity system, achieved by embedding an InAs quantum dot molecule within a photonic crystal cavity. With this system we obtain a spin singlet-triplet Λ-system where the ground-state spin splitting exceeds the cavity linewidth by an order of magnitude. This allows us to observe cavity-stimulated Raman emission that is highly spin-selective. Moreover, we demonstrate the first cases of cavity-enhanced optical nonlinearities in a solid-state Λ-system. This provides an all-optical, local method to control the spin exchange splitting. Incorporation of a highly engineerable quantum dot molecule into the photonic crystal architecture advances prospects for a quantum network.

  7. Fabrication of a centimeter-long cavity on a nanofiber for cavity quantum electrodynamics.

    PubMed

    Keloth, Jameesh; Nayak, K P; Hakuta, K

    2017-03-01

    We report the fabrication of a 1.2 cm long cavity directly on a nanofiber using femtosecond laser ablation. The cavity modes with finesse values in the range of 200-400 can enable the "strong-coupling" regime of cavity QED, with high cooperativity of 10-20, for a single atom trapped 200 nm away from the fiber surface [Phys. Rev. A80, 053826 (2009)PLRAAN1050-294710.1103/PhysRevA.80.053826]. Such cavity modes can still maintain the transmission between 40%-60%, suggesting a one-pass intracavity transmission of 99.53%. Other cavity modes, which can enable cooperativity in the range of 3-10, show transmission over 60%-85% and are suitable for fiber-based single-photon sources and quantum nonlinear optics in the "Purcell" regime.

  8. Recent advances in coupled laser cavity design

    NASA Astrophysics Data System (ADS)

    Leger, James R.; Chiang, Hung-Sheng; Nilsson, Johan; Ji, Junhau; Sahu, Jayanta

    2013-03-01

    External cavity coherent beam combining represents a path forward to higher fiber laser radiance, with several groups demonstrating scalable approaches. In this paper, we review recent advances in coupled laser cavity design. In particular, we compare various designs and describe the pros and cons of each with regard to sensitivity to path length errors. Experimental measurements using a specially designed dual-core fiber demonstrate the modal loss from a superposition architecture. A second area of investigation is concerned with Q-switch suppression in coupled laser cavities. The increased cavity loss that accompanies path length errors in the laser arms can suppress lasing, causing an energy build-up in the laser inversion. When the path length errors are removed and the cavity resumes its low loss state, the stored energy can be released in a manner analogous to Q-switching, creating a giant laser pulse. Since the peak power of this pulse can be many orders of magnitude larger than the cw power, the high instantaneous intensity can cause irreparable damage to optical components. We investigate passive systems that are designed to suppress this unwanted Q-switching by allowing alternative lasing paths to clamp the gain.

  9. Long Wave Infrared Cavity Enhanced Sensors

    SciTech Connect

    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.

  10. Inflammatory oral cavity diseases of the cat.

    PubMed

    Pedersen, N C

    1992-11-01

    There is a great deal of frustration among veterinarians about the diagnosis and treatment of inflammatory diseases of the oral cavity of the cat. This frustration is due to both the high frequency of feline oral inflammatory lesions and our poor understanding of their causes. This poor understanding can be blamed on several things: (1) a rapidly emerging, but still relatively poor, understanding of feline diseases in general and nutrition in particular; (2) a tendency to lump rather than separate specific oral inflammations; (3) a tendency not to use a thorough and systematic approach to diagnosing oral cavity disease; and (4) the reluctance of veterinarians to apply what is already known about human oral cavity diseases to cats. When problems 2 through 4 are adequately addressed, it becomes apparent that we really know more about oral cavity disease in the cat than we thought we knew and that great progress has been made. The task ahead is to define, in precise medical terms, those remaining disease entities of the oral cavity that pose the greatest health risk to cats, to apply what has been already been discovered from human disease counterparts, and to study them systematically.

  11. Multi-Mode Cavity Accelerator Structure

    SciTech Connect

    Jiang, Yong; Hirshfield, Jay Leonard

    2016-11-10

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

  12. Plasmonic band gap cavities on biharmonic gratings

    NASA Astrophysics Data System (ADS)

    Kocabas, Askin; Seckin Senlik, S.; Aydinli, Atilla

    2008-05-01

    In this paper, we have experimentally demonstrated the formation of plasmonic band gap cavities in infrared and visible wavelength range. The cavity structure is based on a biharmonic metallic grating with selective high dielectric loading. A uniform metallic grating structure enables strong surface plasmon polariton (SPP) excitation and a superimposed second harmonic component forms a band gap for the propagating SPPs. We show that a high dielectric superstructure can dramatically perturb the optical properties of SPPs and enables the control of the plasmonic band gap structure. Selective patterning of the high index superstructure results in an index contrast in and outside the patterned region that forms a cavity. This allows us to excite the SPPs that localize inside the cavity at specific wavelengths, satisfying the cavity resonance condition. Experimentally, we observe the formation of a localized state in the band gap and measure the dispersion diagram. Quality factors as high as 37 have been observed in the infrared wavelength. The simplicity of the fabrication and the method of testing make this approach attractive for applications requiring localization of propagating SPPs.

  13. Expulsion of Fibroids to the Endometrial Cavity after Magnetic Resonance Imaging-guided High Intensity Focused Ultrasound Surgery (MRgFUS) Treatment of Intramural Uterine Fibroids

    PubMed Central

    Jeong, Jae-Hyeok; Hong, Gil Pyo; Kim, Yu-Ri; Hong, Da Gyo; Ha, Jae-Eun; Yeom, Jung In; Kim, Eun-Jeong; Kim, Hyung-Il

    2016-01-01

    Objectives This report seeks to introduce some cases of the patients who received magnetic resonance imaging (MRI)-guided high intensity focused ultrasound (HIFU) surgery (MRgFUS)-based intramural uterine fibroids treatment where the post-MRgFUS intramural uterine fibroids decreased in its volume and protruded towards the endometrial cavity to be expelled by hysteroscopy. Methods Of the 157 patients who had received MRgFUS treatment in the Obstetrics and Gynecology of the Hospital from March, 2015 to February, 2016; this study examined 6 of the cases where, after high intensity focused ultrasound treatment, intramural uterine fibroids protruded towards the endometrial cavity to be removed by hysteroscopic myomectomy. The high intensity focused ultrasound utilized in the cases were Philips Achieva 1.5 Tesla MR (Philips Healthcare, Best, The Netherlands) and Sonalleve HIFU system. Results The volume of fibroids ranged from 26.0 cm3 to 199.5 cm3, averaging 95.6 cm3. The major axis length ranged from 4.0 cm to 8.2 cm, averaging 6.3 cm. Fibroid location in all of the patients was in intramural uterine before treatment but after the high intensity focused ultrasound treatment, the fibroids were observed to protrude towards the endometrial cavity in at least Day 5 or up to Day 73 to allow hysteroscopic myomectomy. Conclusions In some cases, after an intramural uterine fibroid is treated with MRgFUS, fibroid volume is decreased and the fibroid protrudes towards the endometrial cavity. In this case, hysteroscopic myomectomy can be a useful solution. PMID:28119893

  14. Optical Resonant Cavity in a Nanotaper

    SciTech Connect

    Lee, Sang Hyun; Goto, Takenari; Miyazaki, Hiroshi; Chang, Jiho; Yao, Takafumi

    2010-01-01

    The present study describes an optical resonant cavity in a nanotaper with scale reduction from micro to several nanometers. Both experimental results and a finite-difference time-domain (FDTD)-based simulation suggested that the nanometer-scale taper with a diameter similar to the wavelength of light acted as a mirror, which facilitated the formation of a laser cavity and caused lasing in ZnO nanotapers. As the light inside the nanotaper propagated toward the apex, the lateral mode was reduced and reflection occurred. This report suggests that use of the resonant optical cavities in nanotapers might result in novel active and passive optical components, which will broaden the horizons of photonic technology.

  15. Plasmonic coaxial waveguide-cavity devices.

    PubMed

    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.

  16. Enhanced Method for Cavity Impedance Calculations

    SciTech Connect

    Frank Marhauser, Robert Rimmer, Kai Tian, Haipeng Wang

    2009-05-01

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

  17. Harmonic cavities for the NLC damping rings

    SciTech Connect

    de Santis, S.; Wolski, A.

    2003-05-29

    To achieve high luminosity, a linear collider needs damping rings to produce beams with very small transverse emittances. In the NLC, design constraints place the Main Damping Rings in a parameter regime where intrabeam scattering (IBS) is likely to be a limitation on the emittance, and hence on the final luminosity. It is possible to mitigate the effects of IBS by lengthening the bunch: this may be achieved by redesigning the lattice with higher momentum compaction, or by use of higher harmonic cavities. Here, we consider the latter approach. We estimate the required bunch lengthening that might be needed, outline some appropriate parameters for the harmonic cavities, and discuss some of the effects that might be introduced or exacerbated by the cavities, such as synchronous phase variation along the bunch train.

  18. Coupled External Cavity Photonic Crystal Enhanced Fluorescence

    PubMed Central

    Pokhriyal, Anusha; Lu, Meng; Ge, Chun; Cunningham, Brian T.

    2016-01-01

    We report a fundamentally new approach to enhance fluorescence in which surface adsorbed fluorophore-tagged biomolecules are excited on a photonic crystal surface that functions as a narrow bandwidth and tunable mirror of an external cavity laser. This scheme leads to ~10× increase in the electromagnetic enhancement factor compared to ordinary photonic crystal enhanced fluorescence. In our experiments, the cavity automatically tunes its lasing wavelength to the resonance wavelength of the photonic crystal, ensuring optimal on-resonance coupling even in the presence of variable device parameters and variations in the density of surface-adsorbed capture molecules. We achieve ~105× improvement in the limit of detection of a fluorophore-tagged protein compared to its detection on an unpatterned glass substrate. The enhanced fluorescence signal and easy optical alignment make cavity-coupled photonic crystals a viable approach for further reducing detection limits of optically-excited light emitters that are used in biological assays. PMID:23129575

  19. Coupled external cavity photonic crystal enhanced fluorescence.

    PubMed

    Pokhriyal, Anusha; Lu, Meng; Ge, Chun; Cunningham, Brian T

    2014-05-01

    We report a fundamentally new approach to enhance fluorescence in which surface adsorbed fluorophore-tagged biomolecules are excited on a photonic crystal surface that functions as a narrow bandwidth and tunable mirror of an external cavity laser. This scheme leads to ∼10× increase in the electromagnetic enhancement factor compared to ordinary photonic crystal enhanced fluorescence. In our experiments, the cavity automatically tunes its lasing wavelength to the resonance wavelength of the photonic crystal, ensuring optimal on-resonance coupling even in the presence of variable device parameters and variations in the density of surface-adsorbed capture molecules. We achieve ∼10(5) × improvement in the limit of detection of a fluorophore-tagged protein compared to its detection on an unpatterned glass substrate. The enhanced fluorescence signal and easy optical alignment make cavity-coupled photonic crystals a viable approach for further reducing detection limits of optically-excited light emitters that are used in biological assays.

  20. ERRATUM: Effective emissivity of a cylindrical cavity with an inclined bottom: I. Isothermal cavity Effective emissivity of a cylindrical cavity with an inclined bottom: I. Isothermal cavity

    NASA Astrophysics Data System (ADS)

    Prokhorov, Alexander V.; Hanssen, Leonard M.

    2009-12-01

    In table 2 of this paper, the values of the normal effective emissivity are presented, instead of values of the hemispherical effective emissivity for an isothermal cavity with β = 30°. Here, we present the corrected portion of table 2. Also, in figure 5 (right-side plot) and figure 6 (left column, second row), instead of a cavity with β = 58°, the plots for a cavity with slightly different geometric parameters are shown. We show here the corrected map of reflections and a three-dimensional plot of the distribution of the local normal effective emissivity. The corrected portions of table 2, figure 5 and figure 6 are given in the pdf file.