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Sample records for split coaxial rfq

  1. Split coaxial RFQ structure with modulated vanes

    International Nuclear Information System (INIS)

    Arai, S.

    1983-10-01

    A new split coaxial RFO structure with modulated vanes is proposed. The structure is designed to accelerate 238 U 4+ from 1.68 keV/u to 45.1 keV/u at frequency of 12.5 MHz. The cavity is 1.6 m in diameter and 8 m in length. The cavity consists of four cavity modules divided by three stems which support horizontal and vertical vanes periodically and alternatively. At the same time, problems on the beam dynamics and design procedures are described and discussed. (orig.)

  2. Analysis of a multi-module split coaxial RFQ

    International Nuclear Information System (INIS)

    Arai, Shigeaki.

    1986-11-01

    A split coaxial RFQ linac with modulated vanes is under development for acceleration of very heavy ions. As a first step, a 1/4 scaled model with flat vanes has been constructed. Easy assembling of vanes and good mechanical stability of the structure have been achieved by employing a multi-module cavity arrangement. In this paper, theoretical treatments for the estimation of rf parameters and the interpretation of resonance characteristics are described in detail and their results are compared with the experimental data. The resonant frequency predicted by using the estimated inductance and the measured capacitance agrees with the experimental value within 2 % accuracy. Dispersion characteristics and longitudinal voltage distribution at each resonance mode are qualitatively well explained by an equivalent circuit analysis. (author)

  3. Design study of a 25.5-MHz split coaxial RFQ

    International Nuclear Information System (INIS)

    Arai, Shigeaki; Imanishi, Akira; Morimoto, Teruhisa; Shibuya, Shinji; Tojyo, Eiki; Tokuda, Noboru.

    1989-08-01

    A 25.5-MHz split coaxial RFQ with modulated vanes is now being fabricated. The RFQ, 2.1 m in length and 0.9 m in diameter, will accelerate ions with a charge-to-mass ratio greater than 1/30 from 1 keV/n up to 45.4 keV/n. The design works on beam dynamics and cavity fabrication are reported. (author)

  4. Acceleration tests of the INS 25.5-MHz split coaxial RFQ

    International Nuclear Information System (INIS)

    Arai, S.; Imanishi, A.; Morimoto, T.; Tojyo, E.; Tokuda, N.; Shibuya, S.

    1991-05-01

    The INS 25.5-MHz split coaxial RFQ, a linac that accelerates ions with a charge-to-mass ratio greater than 1/30 from 1 to 45.4 keV/u, is now undergoing acceleration tests with a beam of molecular nitrogen (N 2 + ) ions. Results so far obtained show that the RFQ operates in accordance with the design. Presented are preliminary results on the beam performance: emittances of the in- and output beams, output energy and its spread, and beam transmission. (author)

  5. RF tests on the INS 25.5-MHz split coaxial RFQ

    International Nuclear Information System (INIS)

    Shibuya, S.; Arai, S.; Imanishi, A.; Morimoto, T.; Tojyo, E.; Tokuda, N.

    1990-09-01

    A 25.5-MHz split coaxial RFQ with modulated vanes has been constructed. This RFQ will accelerate heavy ions with a charge-to-mass ratio greater than 1/30. We have finished field measurements and obtained the following results: the field strengths between neighboring vanes are same within ±0.6 % over the vane length; the distribution of the intervane voltage in the axial direction is almost flat. Through high power tests so far conducted, we have attained an intervane voltage of 110 kV under a pulse operation with a peak power of 70 kW and a duty factor of 0.9 %. The cavity is thus almost ready for acceleration tests. (author)

  6. Acceleration performance of a 50-MHz split coaxial RFQ and the design of a 25.5-MHz prototype

    International Nuclear Information System (INIS)

    Tokuda, N.; Arai, S.; Fukushima, T.; Morimoto, T.; Tojyo, E.

    1989-03-01

    Acceleration tests on a 50-MHz split coaxial RFQ have been conducted at INS. The 2-m long RFQ has accelerated protons from 2 to 60 keV. The experimental results concerning beam emittance and transmission efficiency agree with predictions of a computer simulation. Following this success, we are fabricating a 25.5-MHz prototype of 2-m long. The issues of the study are to establish a structure standing a high-power operation and to accelerate heavy ions with a charge-to-mass ratio larger than 1/30. (author)

  7. Development of a split coaxial RFQ for the JHP heavy ion linac

    International Nuclear Information System (INIS)

    Arai, Shigeaki.

    1990-05-01

    A split coaxial RFQ (SCRFQ) is being developed as the front-end structure of the heavy-ion linac chain planned in the Japanese Hadron Project (JHP). The features of the INS SCRFQ is that four modulated vanes are installed and that the whole cavity comprises short module cavities. The fundamental problems concerning to the rf and mechanical characteristics were clarified and solved through studies with a cold model. This model was then converted to an accelerating model working at 50 MHz. Acceleration tests using a proton beam showed that the linac had the designed performance. A 25.5-MHz prototype for a JHP machine is now under development. The cavity, 2.1 m in length and 0.9 m in diameter, has been built, and will accelerate ions with a charge-to-mass ratio greater than 1/30 from 1 keV/u to 45 keV/u. From low-power tests so far conducted, we have found that the cavity has good rf characteristics. (author)

  8. The split coaxial linac structure and its RF modes

    International Nuclear Information System (INIS)

    Mueller, R.W.

    1989-01-01

    The Split Coaxial Cavity structure has been invented and applied for the first time in the heavy-ion RFQ linac MAXILAC of GSI. It has an ideally flat RF voltage distribution and a good power economy. From another standpoint, it is a member of the small family of linac structures where the two modes, the wanted one and the unflatness mode, are clearly and strictly separable. The unflatness or ''Q Line'' mode is analyzed in more detail in this paper. It is necessary for the understanding of the interaction of the beam with the cavity, possible beam instabilities resulting from it, and for curing these instabilities with the chance of obtaining improved beams. (orig.)

  9. Low frequency RFQ linacs for heavy ion fusion

    International Nuclear Information System (INIS)

    Moretti, A.; Watson, J.M.; Martin, R.L.; Lari, R.J.; Stockley, R.L.

    1982-01-01

    Low frequency, radio frequency quadrupole (RFQ) structures are under study at Argonne National Laboratory (ANL) as the low-velocity portion of an rf linac driver for heavy ion inertial confinement fusion. Besides offering a direct comparison with the present ANL front end, it would provide a second low-velocity Xe +1 linac for funneling experiments at 22.9 MeV. Heavy ion RFQ accelerators are characterized by their low rf operating frequency of about 10 MHz. The large size of a manifold-fed four-vane, 10 MHz RFQ resonator structure (about 6 m in diameter) makes it unacceptable for heavy ions; therefore, alternate structures are under study at Argonne. The structures under study are: (1) a Wideroe-type structure with external stub lines, (2) a Wideroe-type structure with the stub lines internal to the structure, (3) a split coaxial line resonator with modulated vanes, and (4) a interdigital line resonator with modulated cylindrical rods. The split coaxial line resonator seems best at this low frequency. It is compact and very efficient. About 15.5 m of linac structure excited with 560 kW of rf power is sufficient to accelerate 30 mA of Xe +1 with 97% transmission efficiency from 250 keV to 3 MeV

  10. Investigation of a Novel Coaxial Power-Split Hybrid Powertrain for Mining Trucks

    Directory of Open Access Journals (Sweden)

    Weiwei Yang

    2018-01-01

    Full Text Available Due to the different working conditions and specification requirements of mining trucks when compared to commercial passenger vehicles, better fuel efficiency of mining trucks could lead to more significant economic benefits. Therefore, investigating a hybrid transmission system becomes essential. A coaxial power-split hybrid powertrain system for mining trucks is presented in this paper. The system is characterized as comprising an engine, a generator (MG1, a motor (MC2, two sets of planetary gears, and a clutch (CL1. There are six primary operation modes for the hybrid system including the electric motor mode, the engine mode, the hybrid electric mode, the hybrid and assist mode, the regenerative mode, and the stationary charging mode. The mathematical model of the coaxial power-split hybrid system is established according to the requirements of vehicle dynamic performance and fuel economy performance in a given driving cycle. A hybrid vehicle model based on a rule-based control strategy is established to evaluate the fuel economy. Compared with the Toyota Hybrid System (THS and the conventional mechanical vehicle system using a diesel engine, the simulation results based on an enterprise project indicate that the proposed hybrid system can enhance the vehicle’s fuel economy by 8.21% and 22.45%, respectively, during the given mining driving cycle. The simulation results can be used as a reference to study the feasibility of the proposed coaxial hybrid system whose full potential needs to be further investigated by adopting non-causal control strategies.

  11. RFQ preinjectors

    Science.gov (United States)

    Alessi, J. G.

    1989-04-01

    The radio frequency quadrupole (RFQ) accelerator has become the method of choice as a preinjector for many proton and heavy ion linacs injecting into synchrotrons, and can also be used for injection directly into small synchrotrons. In addition to its use in most new preinjector lines being built or proposed, several laboratories have replaced Cockcroft-Wallon accelerators with RFQs. Among the advantages of the RFQ are its simplicity and reliability, compact size, and relatively low cost. The fact that the ion source is located nearly at ground potential is also very advantageous. A survey of operating RFQ preinjectors is given, as well as the status of some RFQ preinjectors which are presently under development.

  12. RFQ preinjectors

    International Nuclear Information System (INIS)

    Alessi, J.G.

    1988-01-01

    The Radio Frequency Quadrupole (RFQ) accelerator has become the method of choice as a preinjector for many proton and heavy ion linacs injecting into synchrotrons, and can be used for injection directly into small synchrotrons. In addition to its use in most new preinjector lines being built or proposed, several laboratories have replaced Cockcroft-Walton accelerators with RFQs. Among the advantages of the RFQ are its simplicity and reliability, compact size, and relatively low cost. The fact that the ion source is located nearly at ground potential is also very advantageous. A survey of operating RFQ preinjectors is given, as well as the status of some RFQ preinjectors which are presently under development. 25 refs

  13. Performance analysis of a novel coaxial power-split hybrid powertrain using a CNG engine and supercapacitors

    International Nuclear Information System (INIS)

    Ouyang, Minggao; Zhang, Weilin; Wang, Enhua; Yang, Fuyuan; Li, Jianqiu; Li, Zhongyan; Yu, Ping; Ye, Xiao

    2015-01-01

    Highlights: • Four different types of hybrid powertrain for heavy-duty vehicles are reviewed. • A novel coaxial power-split hybrid powertrain is proposed and models are developed. • Performance characteristics are analyzed and compared to a conventional powertrain. • Fuel saving potential is evaluated and explained using energy efficiency method. - Abstract: Energy conservation is a very important task for the automotive industry. The use of hybrid electric vehicles can improve energy efficiency, thus reducing fuel consumption and carbon emissions. In this research, the performance characteristics of a novel coaxial power-split hybrid powertrain for a transit bus are presented. The power sources are a combination of a compressed natural gas (CNG) engine and supercapacitors. A mathematical model for the coaxial power-split hybrid powertrain is established. Subsequently, an analysis program is developed based on Matlab and Advisor. The parameters are specified using experimental data. Afterwards, a rule-based control strategy is designed and optimized from the viewpoint of energy efficiency. Later, the system performance is evaluated using the Chinese Transit Bus City Driving Cycle and compared to a conventional powertrain. The results indicate that the proposed coaxial power-split hybrid powertrain can fulfill the requirements of the transit bus and enhance the energy efficiency dramatically. Moreover, the average energy efficiency of the supercapacitors was found to be above 97% over the entire driving cycle. Using supercapacitors as energy storage devices for the coaxial power-split hybrid powertrain can effectively recover the kinetic energy during regenerative braking and is a good solution for transit buses that require frequent acceleration and deceleration.

  14. Beam tests of the 12 MHz RFQ RIB injector for ATLAS

    International Nuclear Information System (INIS)

    Kaye, R. A.

    1999-01-01

    In recent tests without beam, the Argonne 12 MHz split-coaxial radio-frequency quadruple (RFQ) achieved a cw intervane voltage of more than 100 kV, the design operating voltage for the device. This voltage is sufficient for the RFQ to function as the first stage of a RIB injector for the Argonne Tandem Linear Accelerator System (ATLAS). Previously reported beam dynamics calculations for the structure predict longitudinal emittance growth of only a few keV·ns for beams of mass 132 and above with transverse emittance of 0.27 π mm·mrad (normalized). Such beam quality is not typical of RFQ devices. The work reported here is preparation for tests with beams of mass up to 132. Beam diagnostic stations are being developed to measure the energy gain and beam quality of heavy ions accelerated by the RFQ using the Dynamitron accelerator facility at the ANL Physics Division as the injector. Beam diagnostic development includes provisions for performing the measurements with both a Si charged-particle detector and an electrostatic energy spectrometer system

  15. Development of an RFQ linac for unstable nuclei

    International Nuclear Information System (INIS)

    Arai, S.; Imanishi, A.; Morimoto, T.; Shibuya, S.; Tojyo, E.; Tokuda, N.

    1990-05-01

    A split coaxial RFQ (SCRFQ) is being developed for accelerating unstable nuclei with a charge-to-mass ratio larger than 1/60 from 1 to 170 keV/u in the JHP heavy-ion linac. The SCRFQ is equipped with modulated vanes to generate ideal quadrupole and accelerating fields. The fundamental problems on the SCRFQ have been clarified and solved through studies on a cold model, and the excellent accelerating performance has been confirmed by using a proton accelerating model working at 50 MHz. A 25.5-MHz prototype for the JHP SCRFQ is now under development. The prototype, 2.1 m in length and 0.9 m in diameter, will accelerate ions with a charge-to-mass ratio larger than 1/30 from 1 to 45 keV/u. Low-power tests conducted so far show that the prototype cavity has good rf characteristics. (author)

  16. Cw RFQ development

    International Nuclear Information System (INIS)

    Schriber, S.O.

    1985-01-01

    A review of research and development related to fabricating and operating radio-frequency quadrupole (RFQ) structures at 100% duty cycle [continuous wave (cw)] is presented, with emphasis on work at the Los Alamos National Laboratory, the Chalk River Nuclear Laboratories, and the University of Frankfurt. Activities in other areas that have an impact on operating cw RFQ systems will be highlighted. 27 refs

  17. RFQ1 diagnostic devices

    International Nuclear Information System (INIS)

    Chidley, B.G.; Arbique, G.M.; de Jong, M.S.; McMichael, G.E.; Michel, W.L.; Smith, B.H.

    1991-01-01

    The diagnostic devices in use on RFQ1 will be described. They consist of a double-slit emittance-measuring unit, a 45 degree deflection energy-analysis magnet, parametric current transformers, optical beam sensors, beam-stop current monitors, and an x-ray end-point analyzer. All of these devices are able to operate up to the full output current of RFQ1 (75 mA cw at 0.6 MeV)

  18. RFQ development at Los Alamos

    International Nuclear Information System (INIS)

    Wangler, T.P.; Crandall, K.R.; Stokes, R.H.

    1982-01-01

    The basic principles of the radio-frequency quadrupole (RFQ) linac are reviewed and a summary of past and present Los Alamos work is presented. Some beam-dynamics effects, important for RFQ design, are discussed. A design example is shown for xenon and a brief discussion of low-frequency RFQ structures is given

  19. RFQ development at LBL

    International Nuclear Information System (INIS)

    Abbott, S.; Brodzik, D.; Gough, R.A.; Howard, D.; Lancaster, H.; Mac Gill, R.; Rovanpera, S.; Schneider, H.

    1983-01-01

    The radio frequency quadrupole (RFQ) is a structure which can efficiently focus, bunch and accelerate low velocity ion beams. It has many features which make it particularly attractive for applications in the biomedical and nuclear sciences. There are two projects in progress at LBL where the incorporation of heavy ion RFQ technology offers substantial benefits: in the upgrade of the Bevatron local injector, and in the design of a dedicated heavy ion medical accelerator. In order to meet the requirements of these two important applications, a 200 MHz RFQ structure has been designed for ions with charge to mass ratios as low as 0.14, and a low RF power scale model has been built and tested. Construction of the high power model has begun. The status of this project is reviewed and a summary of technical specifications given

  20. RFQ development at INS

    International Nuclear Information System (INIS)

    Nakanishi, T.; Ueda, N.; Arai, S.

    1984-01-01

    The INS RFQ linac 'LITL' (Lithium Ion Test Linac) with a four vane structure is driven with a single loop coupler, and accelerates ions with q/A >= 1/7 from 5 to 138 keV/u through the vane length of 1.22 m. The acceleration tests show the LITL has acceptances predicted by a computer simulation. Operation of the machine is easy and stable. On the basis of the experience with the successful operation, we are designing and constructing a longer RFQ with cw operation. The 100 MHz RFQ linac of --7 m long accelerates ions with q/A = 1/7 to 800 keV/u. The machine consists of four tanks with vanes of 1.8 m. A computer simulation shows that misalignments within 0.1 mm of the beam axes of the tanks scarecely affect particle motions. (author)

  1. Tuning the LEDA RFQ 6.7 MeV accelerator

    International Nuclear Information System (INIS)

    Young, L.M.; Rybarcyk, L.

    1998-01-01

    This paper presents the results of tuning the 8 meter long Radio Frequency Quadrupole (RFQ) built for the Low Energy Demonstration Accelerator (LEDA). This 350-MHz RFQ is split into four 2-meter-long-RFQs. Then they are joined with resonant coupling to form an 8-meter-long RFQ. This improves both the longitudinal stability and the transverse stability of this long RFQ. The frequencies of the modes near the RFQ mode are measured. The authors show the effect on the RF fields of an error in the temperature of each one of the 2-meter-long-RFQs. Slug tuners distributed along the outer walls tune the RFQ. The program RFQTUNE is used to determine the length of the tuners. The tuners are machined to length when the final tuning is complete

  2. RFQ modeling computer program

    International Nuclear Information System (INIS)

    Potter, J.M.

    1985-01-01

    The mathematical background for a multiport-network-solving program is described. A method for accurately numerically modeling an arbitrary, continuous, multiport transmission line is discussed. A modification to the transmission-line equations to accommodate multiple rf drives is presented. An improved model for the radio-frequency quadrupole (RFQ) accelerator that corrects previous errors is given. This model permits treating the RFQ as a true eight-port network for simplicity in interpreting the field distribution and ensures that all modes propagate at the same velocity in the high-frequency limit. The flexibility of the multiport model is illustrated by simple modifications to otherwise two-dimensional systems that permit modeling them as linear chains of multiport networks

  3. Design for a superconducting niobium RFQ structure

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K W; Kennedy, W L; Sagalovsky, L [Argonne National Lab., IL (United States)

    1992-11-01

    This paper reports a design for a niobium superconducting RFQ operating at 192 Mhz. The structure is of the rod and post type, novel in that each of four rods is supported by two posts oriented radially with respect to the beam axis. Although the geometry has four-fold rotation symmetry, the dipole-quadrupole mode splitting is large, giving good mechanical tolerances. The simplicity of the geometry enables designing for good mechanical stability while minimizing tooling costs for fabrication with niobium. Results of MAFIA numerical modeling, measurements on a copper model, and plans for a beam test are discussed. (Author) fig., 7 refs.

  4. Construction of a superconducting RFQ structure

    International Nuclear Information System (INIS)

    Shepard, K.W.; Kennedy, W.L.; Crandall, K.R.

    1993-01-01

    This paper reports the design and construction status of a niobium superconducting RFQ operating at 194 MHz. The structure is of the rod and post type, novel in that each of four rods is supported by two posts oriented radially with respect to the beam axis. Although the geometry has four-fold rotation symmetry, the dipole-quadrupole mode splitting is large, giving good mechanical tolerances. The simplicity of the geometry enables designing for good mechanical stability while minimizing tooling costs for fabrication with niobium. Design details of a prototype niobium resonator, results of measurements on room temperature models, and construction status are discussed

  5. Design for a superconducting niobium RFQ structure

    International Nuclear Information System (INIS)

    Shepard, K.W.; Kennedy, W.L.; Sagalovsky, L.

    1992-01-01

    This paper reports a design for a niobium superconducting RFQ operating at 192 Mhz. The structure is of the rod and post type, novel in that each of four rods is supported by two posts oriented radially with respect to the beam axis. Although the geometry has four-fold rotation symmetry, the dipole-quadrupole mode splitting is large, giving good mechanical tolerances. The simplicity of the geometry enables designing for good mechanical stability while minimizing tooling cost for fabrication with niobium. Results of MAFIA numerical modeling, measurements on a copper model, and plans for a beam test are discussed

  6. Design for a superconducting niobium RFQ structure

    International Nuclear Information System (INIS)

    Shepard, K.W.; Kennedy, W.L.; Sagalovsky, L.

    1992-01-01

    This paper reports a design for a niobium superconducting RFQ operating at 192 Mhz. The structure is of the rod and post type, novel in that each of four rods is supported by two posts oriented radially with respect to the beam axis. Although the geometry has four-fold rotation symmetry, the dipole-quadrupole mode splitting is large, giving good mechanical tolerances. The simplicity of the geometry enables designing for good mechanical stability while minimizing tooling costs for fabrication with niobium. Results of MAFIA numerical modeling, measurements on a copper model, and plans for a beam test are discussed. (Author) fig., 7 refs

  7. Construction of a superconducting RFQ structure

    International Nuclear Information System (INIS)

    Shepard, K.W.; Givens, J.; Potter, J.M.

    1994-01-01

    This paper reports the development status of a niobium superconducting RFQ operating at 194 Mhz. The structure is of the rod and post type, novel in that each of four rods is supported by two posts oriented radially with respect to the beam axis. Although the geometry has four-fold rotation symmetry, the dipole-quadrupole mode splitting is large, giving good mechanical tolerances. The length of the structure is 52 cm, and the vanes are modulated to enable tests with an ion beam. The construction of a prototype niobium resonator is described

  8. Design for a superconducting niobium RFQ structure

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K.W.; Kennedy, W.L.; Sagalovsky, L.

    1992-01-01

    This paper reports a design for a niobium superconducting RFQ operating at 192 Mhz. The structure is of the rod and post type, novel in that each of four rods is supported by two posts oriented radially with respect to the beam axis. Although the geometry has four-fold rotation symmetry, the dipole-quadrupole mode splitting is large, giving good mechanical tolerances. The simplicity of the geometry enables designing for good mechanical stability while minimizing tooling cost for fabrication with niobium. Results of MAFIA numerical modeling, measurements on a copper model, and plans for a beam test are discussed.

  9. Construction of a superconducting RFQ structure

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K.W.; Kennedy, W.L. [Argonne National Lab., IL (United States); Crandall, K.R. [AccSys Technology, Inc., Pleasanton, CA (United States)

    1993-07-01

    This paper reports the design and construction status of a niobium superconducting RFQ operating at 194 MHz. The structure is of the rod and post type, novel in that each of four rods is supported by two posts oriented radially with respect to the beam axis. Although the geometry has four-fold rotation symmetry, the dipole-quadrupole mode splitting is large, giving good mechanical tolerances. The simplicity of the geometry enables designing for good mechanical stability while minimizing tooling costs for fabrication with niobium. Design details of a prototype niobium resonator, results of measurements on room temperature models, and construction status are discussed.

  10. Design for a superconducting niobium RFQ structure

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K.W.; Kennedy, W.L.; Sagalovsky, L.

    1992-09-01

    This paper reports a design for a niobium superconducting RFQ operating at 192 Mhz. The structure is of the rod and post type, novel in that each of four rods is supported by two posts oriented radially with respect to the beam axis. Although the geometry has four-fold rotation symmetry, the dipole-quadrupole mode splitting is large, giving good mechanical tolerances. The simplicity of the geometry enables designing for good mechanical stability while minimizing tooling cost for fabrication with niobium. Results of MAFIA numerical modeling, measurements on a copper model, and plans for a beam test are discussed.

  11. RFQ simulation code

    International Nuclear Information System (INIS)

    Lysenko, W.P.

    1984-04-01

    We have developed the RFQLIB simulation system to provide a means to systematically generate the new versions of radio-frequency quadrupole (RFQ) linac simulation codes that are required by the constantly changing needs of a research environment. This integrated system simplifies keeping track of the various versions of the simulation code and makes it practical to maintain complete and up-to-date documentation. In this scheme, there is a certain standard version of the simulation code that forms a library upon which new versions are built. To generate a new version of the simulation code, the routines to be modified or added are appended to a standard command file, which contains the commands to compile the new routines and link them to the routines in the library. The library itself is rarely changed. Whenever the library is modified, however, this modification is seen by all versions of the simulation code, which actually exist as different versions of the command file. All code is written according to the rules of structured programming. Modularity is enforced by not using COMMON statements, simplifying the relation of the data flow to a hierarchy diagram. Simulation results are similar to those of the PARMTEQ code, as expected, because of the similar physical model. Different capabilities, such as those for generating beams matched in detail to the structure, are available in the new code for help in testing new ideas in designing RFQ linacs

  12. RFQ'S in research and industry

    International Nuclear Information System (INIS)

    Staples, J.

    1986-06-01

    The Radio Frequency Quadrupole accelerator (RFQ) has now matured to the point where it has found wide application. Many machines are in use as part of a synchrotron injector chain with others in unique and unusual applications. Several new RFQ's are now under construction or operating since the last survey. They are of various configurations, making use of various techniques of fabrication and field stabilization. Duty factors are being pushed up, new beam dynamics design techniques are to be used and emittance blow up mechanisms are better understood. Finally, RFQ's are moving from the laboratory to the commercial marketplace

  13. Introduction to RFQ session

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1984-01-01

    It has been close to 15 years now since our colleagues I.M. Kapchinskii and V.A. Teplyakov in the USSR conceived their spatially uniform-focusing idea in the form of practical circuits for focusing and accelerating low-velocity ion beams using electrostatic fields. Almost seven years ago, J.J. Manca whetted our curiosity at Los Alamos by pointing out from Kapchinskii and Teplyakov's work a structure that could capture nearly 100% of an ion beam injected at a few tens of keV/nucleon and accelerate it with little emittance growth to a few MeV. Now the accelerator community at large has realized that a revolution has taken place, and almost everyone is involved. At the 1981 Linac Conference at Bishop's Lodge in Santa Fe, about 17 papers dealt with aspects of the radio-frequency quadrupole (RFQ) structure, as it has also come to be known. This is a brief review of the technology. 2 references, 9 figures

  14. Commissioning of the RFQ1 injector

    International Nuclear Information System (INIS)

    Arbique, G.M.; Sheikh, J.Y.; Taylor, T.; Birney, L.F.; Davidson, A.D.; Wills, J.S.C.

    1987-01-01

    The RFQ1 accelerator is being developed at Chalk River to test the limits of the cw RFQ technology. A 50 kV injector has been built and is now being commissioned as the first phase of the program. This paper describes some of the innovative features of the RFQ1 injector and reports on initial operating experience

  15. Coaxial Transducer

    National Research Council Canada - National Science Library

    Ruffa, Anthony A

    2008-01-01

    The invention as disclosed is of a coaxial transducer that uses lead zirconate titanate ceramic or other suitable material as an isolator between the conductors in a coaxial cable to transmit acoustic...

  16. RFQ pole-tip construction

    International Nuclear Information System (INIS)

    Crandall, K.R.; Stovall, J.E.

    1981-01-01

    The success of the radio-frequency quadrupole (RFQ) proof-of-principle (POP) tests conducted in 1980 at Los Alamos have essentially guaranteed that the RFQ linac will be used in many accelerator projects soon. Several RFQs are already under construction at Los Alamos, and we expect to be designing and machining the vanes for several RFQs to be built at other installations. The technique for machining the vanes for the POP RFQ was developed by Williams and Potter. While retaining their basic approach, we have modified their technique for generating the data required by the milling machine from the parameters defining the vane shapes. The objective of this exercise has been to develop a generalized fabrication procedure that could be used in commercial machine shops

  17. Rfq With An Increased Energy Gain

    CERN Document Server

    Kapin, Valery

    2004-01-01

    The radio-frequency quadrupole (RFQ) linacs are widely used in the initial part of ion accelerators. For industrial and medical applications, the size of RFQ linac as well as the construction and operation costs are important. Therefore, there is a interest to design a compact RFQ linac. In this paper, RFQ linac is studied with the aim of increasing the energy gain. Parameters of a conventional RFQ linac are usually chosen to ensure beam acceleration and stability, providing the autophasing and strong quadrupole focusing in the longitudinal and transverse directions simultaneously. As results, the accelerating efficiency of RFQ is limited by the transverse defocusing effect, and its value is below of a maximum value, which can be provided by RFQ electrodes. To facilitate these limitations, the well-known idea of alternating phase focusing (APF) is utilized. The APF effects boost transverse focusing, allowing to increase an accelerating efficiency, electrode voltage and decreasing average value of the synchron...

  18. CW RFQ fabrication and engineering

    International Nuclear Information System (INIS)

    Schrage, D.; Young, L.; Roybal, P.

    1998-01-01

    The design and fabrication of a four-vane RFQ to deliver a 100 mA CW proton beam at 6.7 MeV is described. This linac is an Oxygen-Free Electrolytic (OFE) copper structure 8 m in length and was fabricated using hydrogen furnace brazing as the joining technology

  19. New trends in RFQ-development

    International Nuclear Information System (INIS)

    Schempp, A.

    1987-01-01

    New trends in RFQ-development depending on the design goals are presented. Designs for heavy ion RFQs and for highly charged light ions from EBIS source are given. The use of the RFQ to accelerate beams, to accelerate very heavy clusters is shown. The application of the procedure funnel beams with RFQs is outlined. The beam dynamic parameters of the 4-vane RFQ for HERA are given

  20. The circular RFQ storage ring

    International Nuclear Information System (INIS)

    Ruggiero, A.G.

    1998-01-01

    This paper presents a novel idea of storage ring for the accumulation of intense beams of light and heavy ions at low energy. The new concept is a natural development of the combined features used in a conventional storage ring and an ion trap, and is basically a linear RFQ bend on itself. In summary the advantages are: smaller beam dimensions, higher beam intensity, and a more compact storage device

  1. The Circular RFQ Storage Ring

    International Nuclear Information System (INIS)

    Ruggiero, A. G.

    1999-01-01

    This paper presents a novel idea of storage ring for the accumulation of intense beams of light and heavy ions at low energy. The new concept is a natural development of the combined features of conventional storage rings and ion traps, and is basically a linear RFQ bent on itself. The advantages are: smaller beam dimensions, higher beam intensity, and a more compact storage device

  2. A cw 4-rod RFQ linac

    International Nuclear Information System (INIS)

    Fujisawa, Hiroshi

    1994-01-01

    A cw 4-rod RFQ linac system has been designed, constructed, and tested as an accelerator section of a MeV-class ion implanter system. The tank diameter is only 60 cm for 34 MHz operating frequency. An equally spaced arrangement of the RFQ electrode supporting plates is proved to be suitable for a low resonant frequency 4-rod RFQ structure. The RFQ electrode cross section is not circular but rectangular to make the handling and maintenance of the electrodes easier. The machining of the electrode is done three dimensionally. Second order corrections in the analyzing magnet of the LEBT (Low Energy Beam Transport) section assure a better transmission through and the matching to the RFQ. A new approach is introduced to measure the rf characteristics of the 4-rod RFQ. This method requires only a few capacitors and a network analyzer. Both the rf and thermal stability of the 4-rod RFQ are tested up to cw 50 kW. Beam experiments with several ions confirm the acceleration of beams to the goal energy of 83 keV/u. The ion beam intensities obtained at the RFQ output for He + , N 2+ , and C + are 32, 13, and 220 pμA, respectively. The measured beam transmissions of >80% agree with the PARMTEQ calculations. The ion implantation method also gives definitive information on the energies of an RFQ output beam. ((orig.))

  3. 4-rod RFQ linac for ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Fujisawa, Hiroshi; Hamamoto, Nariaki; Inouchi, Yutaka [Nisshin Electric Co. Ltd., Kyoto (Japan)

    1997-03-01

    A 34 MHz 4-rod RFQ linac system has been upgraded in both its rf power efficiency and beam intensity. The linac is able to accelerate in cw operation 0.83 mA of a B{sup +} ion beam from 0.03 to 0.91 MeV with transmission of 61 %. The rf power fed to the RFQ is 29 kW. The unloaded Q-value of the RFQ has been improved approximately 61 % to 5400 by copper-plating stainless steel cooling pipes in the RFQ cavity. (author)

  4. Radio-frequency quadrupole, RFQ-1

    CERN Document Server

    CERN PhotoLab

    1982-01-01

    In 1983, RFQ-1 replaced the Cockcroft-Walton generator for the acceleration of protons and H- to 520 keV. This picture shows the RFQ in a test tank (not vacuum-fit) for RF tests using the bead-pull method. See also 8202557 and 8202559. For the final version and more details, see 8303019 and 8303511.

  5. Radio-frequency quadrupole, RFQ-1

    CERN Multimedia

    CERN PhotoLab

    1982-01-01

    In 1983, RFQ-1 replaced the Cockcroft-Walton generator for the acceleration of protons and H- to 520 keV. This picture shows the RFQ in a test tank (not vacuum-fit) for RF tests using the bead-pull method. See also 8202557 and 8202558. For the final version and more details, see 8303019 and 8303511.

  6. Radio-frequency quadrupole, RFQ-1

    CERN Multimedia

    CERN PhotoLab

    1982-01-01

    In 1983, RFQ-1 replaced the Cockcroft-Walton generator for the acceleration of protons and H- to 520 keV. This picture shows the RFQ in a test-tank (not vacuum-fit) for RF tests using the bead-pull method. See also 8202558 and 8202559. For the final version and more details, see 8303019 and 8303511.

  7. Low-charge-state RFQ injector

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K.W.; Kim, J.W.

    1995-08-01

    Preliminary design work was done for a short, normally-conducting RFQ entrance section for a low-charge-state linac. Early results indicate that a low- frequency (12 MHz) RFQ, operated on a high-voltage platform, and injected with a pre-bunched beam, can provide ATLAS quality beams of ions of charge-to-mass ratio less than 1/132.

  8. RFQ scaling-law implications and examples

    International Nuclear Information System (INIS)

    Wadlinger, E.A.

    1986-01-01

    We demonstrate the utility of the RFQ scaling laws that have been previously derived. These laws are relations between accelerator parameters (electric field, fr frequency, etc.) and beam parameters (current, energy, emittance, etc.) that act as guides for designing radio-frequency quadrupoles (RFQs) by showing the various tradeoffs involved in making RFQ designs. These scaling laws give a unique family of curves, at any given synchronous particle phase, that relates the beam current, emittance, particle mass, and space-charge tune depression with the RFQ frequency and maximum vane-tip electric field when assuming equipartitioning and equal longitudinal and transverse tune depressions. These scaling curves are valid at any point in any given RFQ where there is a bunched and equipartitioned beam. We show several examples for designing RFQs, examine the performance characteristics of an existing device, and study various RFQ performance limitations required by the scaling laws

  9. Design and construction of the TIT RFQ

    International Nuclear Information System (INIS)

    Takeda, Osamu; Tanabe, Yoshio; Satoh, Kiyokazu; Kawatsu, Shosi; Okamura, Masahiro; Oguri, Yoshiyuki; Hattori, Toshiyuki.

    1993-01-01

    At Tokyo Institute of Technology (TIT) a four-vane RFQ is to be applied for inertial confinement fusion research. The RFQ(TIT RFQ) is designed for acceleration of particles with charge to mass ratio (q/A) of 1/16 from 5 keV/amu to 213 keV/amu. The planned maximum injection current is 10 mA for 16 O + and beam transmission is expected to be 60% as a result of a PIC code simulation. Structural and thermal analyses were carried out. (author)

  10. A new RFQ linac fabrication technique

    International Nuclear Information System (INIS)

    Schrage, D.; Roybal, P.; Young, L.; Clark, W.; DePaula, R.; Martinez, F.

    1994-01-01

    The use of hydrogen furnace brazing has been applied as a joining technology to the fabrication of a Radio-Frequency-Quadrupole (RFQ) linac for the Los Alamos Accelerator Performance Demonstration Facility (APDF). The design concept provides a monolithic cavity with no longitudinal rf, vacuum, or mechanical joints. A 530 MHz, 0.46 meter long engineering model RFQ has been fabricated and tested at the Los Alamos National Laboratory as a technical demonstration of this concept. It is planned that two funneled RFQ's for the APDF (7 MeV, 350 MHz, 100 mAmp CW, each eight meters in length) will be manufactured by this method

  11. RFQ device for accelerating particles

    Science.gov (United States)

    Shepard, K.W.; Delayen, J.R.

    1995-06-06

    A superconducting radio frequency quadrupole (RFQ) device includes four spaced elongated, linear, tubular rods disposed parallel to a charged particle beam axis, with each rod supported by two spaced tubular posts oriented radially with respect to the beam axis. The rod and post geometry of the device has four-fold rotation symmetry, lowers the frequency of the quadrupole mode below that of the dipole mode, and provides large dipole-quadrupole mode isolation to accommodate a range of mechanical tolerances. The simplicity of the geometry of the structure, which can be formed by joining eight simple T-sections, provides a high degree of mechanical stability, is insensitive to mechanical displacement, and is particularly adapted for fabrication with superconducting materials such as niobium. 5 figs.

  12. RFQ device for accelerating particles

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, Kenneth W. (Park Ridge, IL); Delayen, Jean R. (Naperville, IL)

    1995-01-01

    A superconducting radio frequency quadrupole (RFQ) device includes four spaced elongated, linear, tubular rods disposed parallel to a charged particle beam axis, with each rod supported by two spaced tubular posts oriented radially with respect to the beam axis. The rod and post geometry of the device has four-fold rotation symmetry, lowers the frequency of the quadrupole mode below that of the dipole mode, and provides large dipole-quadrupole mode isolation to accommodate a range of mechanical tolerances. The simplicity of the geometry of the structure, which can be formed by joining eight simple T-sections, provides a high degree of mechanical stability, is insensitive to mechanical displacement, and is particularly adapted for fabrication with superconducting materials such as niobium.

  13. Digital LLRF System for RFQ

    International Nuclear Information System (INIS)

    Agashe, Alok; Motiwala, P.D.; Bharade, S.K.; Mohan, Shyam; Joshi, Gopal; Das, D.

    2015-01-01

    A Low level RF (LLRF) system based on digital techniques has been developed for RFQ of Low Energy High Intensity Proton Accelerator (LEHIPA). The basic LLRF system for RFQ is composed of a Front end analog module housed in a 19 inch bin and a 6U cPCI based Digital board having a high speed and high density FPGA onboard, supporting 32 bit/33MHz PCI ver2.0 protocol and housed in a 19 inch cPCI crate. It also has a cPCI based CPU board with QNX operating system. The cPCI crate is connected to control room via Ethernet. Analog module conditions the input field signals from RF cavity and makes it compatible to digital board. It also amplifies RF Drive signal (Modulator output) from digital board, which goes to high power amplifier. The digital board digitally processes the input RF signals, and generates RF drive signal, which after amplification, used for driving the resonant cavity. The main features of digital board are under-sampling of input RF signals, digital in-phase and quadrature detection, and a proportional- integral (PI) controller algorithm implemented in a FPGA. The LLRF system works in CW as well as in PULSE mode. It also has a DDS implemented in VHDL, used for conditioning and tracking/tuning of the cavity. LLRF system operates under QNX based equipment frontend application and client running from control room. One analog module and one digital board set, supports one resonant cavity. The present paper describes the development of an LLRF system and its results with a test cavity. (author)

  14. Simulation of 6 1/8 inch rigid coaxial RF transmission line

    International Nuclear Information System (INIS)

    Soni, Atul; Pande, M.M.; Rao, M.K.V.; Handu, V.K.

    2006-01-01

    A radio frequency (RF) transmission line has been designed based upon rigid coaxial 6 1/8 , 50-ohm line for coupling the RF power from its source to 400 KeV radio frequency quadrupole (RFQ) accelerator. Simulation and analysis have been carried out to evaluate various RF parameters of the line. (author)

  15. Investigation of high duty factor ISR RFQ-1000

    International Nuclear Information System (INIS)

    Lu, Y.R.; Chen, C.E.; Fang, J.X.; Gao, S.L.; Guo, J. F.; Guo, Z.Y.; Li, D.S.; Li, W.G.; Pan, O.J.; Ren, X.T.; Wu, Y.; Yan, X.Q.; Yu, J.X.; Yu, M.L.; Ratzinger, U.; Deitinghoff, H.; Klein, H.; Schempp, A.

    2003-01-01

    Two Integral Split Ring (ISR) RFQs with high duty factor of 16.7% have been designed for the application of heavy ion implantation and built in the past several years at Institute of Heavy Ion Physics (IHIP) in Peking University. Two kinds of PIG ion sources with permanent magnets and LEBT were installed and optimized for the injection into these two RFQs. The positive O + and negative O - ions were extracted and accelerated separately as well as simultaneously. The output macro pulse O - beam current reached 660 μA at a transmission efficiency of more than 82%. The N + beam was also accelerated with similar transmission efficiency, but the output current intensity for positive ions were lower than the negative ions because of the extracted current limitation of ion sources. The improvements, especially for high duty factor and experimental results with the 1 MeV ISR RFQ will be presented in this paper

  16. Investigation of high duty factor ISR RFQ-1000

    Science.gov (United States)

    Lu, Y. R.; Chen, C. E.; Fang, J. X.; Gao, S. L.; Guo, J. F.; Guo, Z. Y.; Li, D. S.; Li, W. G.; Pan, O. J.; Ren, X. T.; Wu, Y.; Yan, X. Q.; Yu, J. X.; Yu, M. L.; Ratzinger, U.; Deitinghoff, H.; Klein, H.; Schempp, A.

    2003-12-01

    Two Integral Split Ring (ISR) RFQs with high duty factor of 16.7% have been designed for the application of heavy ion implantation and built in the past several years at Institute of Heavy Ion Physics (IHIP) in Peking University. Two kinds of PIG ion sources with permanent magnets and LEBT were installed and optimized for the injection into these two RFQs. The positive O+ and negative O- ions were extracted and accelerated separately as well as simultaneously. The output macro pulse O- beam current reached 660 μA at a transmission efficiency of more than 82%. The N+ beam was also accelerated with similar transmission efficiency, but the output current intensity for positive ions were lower than the negative ions because of the extracted current limitation of ion sources. The improvements, especially for high duty factor and experimental results with the 1 MeV ISR RFQ will be presented in this paper.

  17. Investigation of high duty factor ISR RFQ-1000

    CERN Document Server

    Lu, Y R; Fang, J X; Gao, S L; Guo, J F; Guo, Z Y; Li, D S; Li, W G; Pan, O J; Ren, X T; Wu, Y; Yan, X Q; Yu Jin Xiang; Yu, M L; Ratzinger, U; Deitinghoff, H; Klein, H; Schempp, A

    2003-01-01

    Two Integral Split Ring (ISR) RFQs with high duty factor of 16.7% have been designed for the application of heavy ion implantation and built in the past several years at Institute of Heavy Ion Physics (IHIP) in Peking University. Two kinds of PIG ion sources with permanent magnets and LEBT were installed and optimized for the injection into these two RFQs. The positive O**+ and negative O**- ions were extracted and accelerated separately as well as simultaneously. The output macro pulse O**- beam current reached 660muA at a transmission efficiency of more than 82%. The N**+ beam was also accelerated with similar transmission efficiency, but the output current intensity for positive ions were lower than the negative ions because of the extracted current limitation of ion sources. The improvements, especially for high duty factor and experimental results with the 1MeV ISR RFQ will be presented in this paper.

  18. Utilization of the EBIS with RFQ linacs

    International Nuclear Information System (INIS)

    Hamm, R.W.; Wangler, T.P.

    1981-01-01

    The radio-frequency quadrupole (RFQ) is a new linear accelerator structure in which rf electric fields are used to simultaneously focus, bunch, and accelerate an ion beam. Since the RFQ can provide strong focusing and adiabatic bunching at low velocities, it can capture almost all of the ions extracted from an Electron Beam Ion Source (EBIS) at a low voltage and accelerate them to an energy of 1 to 2 MeV/nucleon in a distance of only a few meters. A successful test at the Los Alamos National Laboratory has confirmed the calculated performance of this structure and has stimulated interest in its use with the EBIS for a variety of applications. The general properties of the RFQ are reviewed, and the utilization of the EBIS with this structure is discussed. Several design examples of this combination are also presented

  19. SPIRAL 2 RFQ Prototype First Tests

    CERN Document Server

    Ferdinand, Robin; Congretel, G; Curtoni, Aline; Delferriere, Olivier; Di Giacomo, Marco; France, Alain; Leboeuf, Didier; Thinel, Jean; Toussaint, Jean-Christian

    2005-01-01

    The SPIRAL2 RFQ is designed to accelerate at 88MHz two kinds of charge-over-mass ratio, Q/A, particles. The proposed injector can accelerate a 5 mA deuteron beam (Q/A=1/2) or a 1 mA particles beam with q/A=1/3 up to 0.75 MeV/A. It is a CW machine which has to show stable operation, provide the request availability, have the minimum losses in order to minimize the activation constraints and show the best quality/cost ratio. The prototype of this 4-vane RFQ has been built and tested. It allowed to verify the mechanical assembly concept (RFQ without any brazing step). The full power was easily injected in the cavity, with no concerns for the RF joints. The paper describes the different achievements.

  20. Performance of the new AGS RFQ preinjector

    International Nuclear Information System (INIS)

    Alessi, J.G.; Brennan, J.M.; Brodowski, J.

    1989-01-01

    In the fall of 1988, the 750 keV Cockcroft-Walton (C-W) preinjector for the AGS 200 MeV H/sup /minus// linac was replaced by an RFQ, in what has proved to be a very successful upgrade. The motivations for the upgrade included improved reliability, simpler maintenance, and the added convenience of having the ion source located at nearly ground potential. At the same time, the controls and instrumentation in the preinjector area were modernized. The linac has been operating full time with this RFQ preinjector since January 1, 1989, and the reliability has been excellent. The source, RFQ, and linac operate at a 5 Hz repetition rate, and the beam pulse width is approximately 450 μs. At this time, the H/sup /minus// current at 200 MeV is typically 23-25 mA, the same as previous operation with the C-W, although the capability is there to reach higher currents in the future. The layout of the new preinjector is shown in Figure 1. An important consideration in the layout of this line was the decision to leave the final 2.4 m section before the linac intact, so the optics of a second C-W injector line and polarized H/sup /minus// injection from another RFQ remained the same. The resulting line has a distance of almost 6 m from the RFQ to the linac, and there are three ''rebuncher'' cavities to maintain the bunching of the beam from the RFQ. The following sections will describe some details of the preinjector line, and then discuss the installation and performance

  1. Performance of the new AGS RFQ preinjector

    Energy Technology Data Exchange (ETDEWEB)

    Alessi, J.G.; Brennan, J.M.; Brodowski, J.; Brown, H.N.; Kponou, A.; LoDestro, V.; Montemurro, P.; Prelec, K.; Witkover, R.; Gough, R.; Staples, J.

    1989-01-01

    In the fall of 1988, the 750 keV Cockcroft-Walton (C-W) preinjector for the AGS 200 MeV H/sup /minus// linac was replaced by an RFQ, in what has proved to be a very successful upgrade. The motivations for the upgrade included improved reliability, simpler maintenance, and the added convenience of having the ion source located at nearly ground potential. At the same time, the controls and instrumentation in the preinjector area were modernized. The linac has been operating full time with this RFQ preinjector since January 1, 1989, and the reliability has been excellent. The source, RFQ, and linac operate at a 5 Hz repetition rate, and the beam pulse width is approximately 450 ..mu..s. At this time, the H/sup /minus// current at 200 MeV is typically 23-25 mA, the same as previous operation with the C-W, although the capability is there to reach higher currents in the future. The layout of the new preinjector is shown in Figure 1. An important consideration in the layout of this line was the decision to leave the final 2.4 m section before the linac intact, so the optics of a second C-W injector line and polarized H/sup /minus// injection from another RFQ remained the same. The resulting line has a distance of almost 6 m from the RFQ to the linac, and there are three ''rebuncher'' cavities to maintain the bunching of the beam from the RFQ. The following sections will describe some details of the preinjector line, and then discuss the installation and performance.

  2. General-purpose RFQ design program

    International Nuclear Information System (INIS)

    Wadlinger, E.A.

    1984-01-01

    We have written a general-purpose, radio-frequency quadrupole (RFQ) design program that allows maximum flexibility in picking design algorithms. This program optimizes the RFQ on any combination of design parameters while simultaneously satisfying mutually compatible, physically required constraint equations. It can be very useful for deriving various scaling laws for RFQs. This program has a friendly user interface in addition to checking the consistency of the user-defined requirements and is written to minimize the effort needed to incorporate additional constraint equations. We describe the program and present some examples

  3. 2.5 MeV CW 4-vane RFQ accelerator design for BNCT applications

    Science.gov (United States)

    Zhu, Xiaowen; Wang, Hu; Lu, Yuanrong; Wang, Zhi; Zhu, Kun; Zou, Yubin; Guo, Zhiyu

    2018-03-01

    Boron Neutron Capture Therapy (BNCT) promises a bright future in cancer therapy for its highly selective destruction of cancer cells, using the 10B +n→7Li +4 He reaction. It offers a more satisfactory therapeutic effect than traditional methods for the treatment of malignant brain tumors, head and neck cancer, melanoma, liver cancer and so on. A CW 4-vane RFQ, operating at 162.5 MHz, provides acceleration of a 20 mA proton beam to 2.5 MeV, bombarding a liquid lithium target for neutron production with a soft neutron energy spectrum. The fast neutron yield is about 1.73×1013 n/s. We preliminarily develop and optimize a beam shaping assembly design for the 7Li(p, n)7Be reaction with a 2.5 MeV proton beam. The epithermal neutron flux simulated at the beam port will reach up to 1 . 575 ×109 n/s/cm2. The beam dynamics design, simulation and benchmark for 2.5 MeV BNCT RFQ have been performed with both ParmteqM (V3.05) and Toutatis, with a transmission efficiency higher than 99.6% at 20 mA. To ease the thermal management in the CW RFQ operation, we adopt a modest inter-vane voltage design (U = 65 kV), though this does increase the accelerator length (reaching 5.2 m). Using the well-developed 3D electromagnetic codes, CST MWS and ANSYS HFSS, we are able to deal with the complexity of the BNCT RFQ, taking the contribution of each component in the RF volume into consideration. This allows us to optimize the longitudinal field distribution in a full-length model. Also, the parametric modeling technique is of great benefit to extensive modifications and simulations. In addition, the resonant frequency tuning of this RFQ is studied, giving the tuning sensitivities of vane channel and wall channel as -16.3 kHz/°C and 12.4 kHz/°C, respectively. Finally, both the multipacting level of this RFQ and multipacting suppressing in the coaxial coupler are investigated.

  4. A CW 4-rod RFQ for deuterons; Ein Hochleistungs-RFQ-Beschleuniger fuer Deuteronen

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, P.

    2007-06-15

    A four-rod RFQ accelerator has been built which operates in CW mode with a power consumption of 250 kW. The assembly of a high power RFQ structure requires a precise mechanical alignment and field tuning of the electrode field. The field distribution must be very flat to enable a proper operation with few losses. Adjusting of the field distribution is critical in long structures. (orig.)

  5. Properties of high current RFQ injectors

    International Nuclear Information System (INIS)

    Schempp, A.; Goethe, J.W.

    1996-01-01

    RFQ linacs are efficient, compact low energy ion structures, which have found numerous applications. They use electrical rf focusing and can capture, bunch and transmit high current ion beams. Some recent development and new projects like a heavy ion injectors for a cyclotron, and the status of the work on high current high duty factor RFQs will be discussed. (author)

  6. Cw operation of the FMIT RFQ accelerator

    International Nuclear Information System (INIS)

    Cornelius, W.D.

    1985-01-01

    Recently, we have achieved reliable cw operation of the Fusion Materials Irradiation Test (FMIT) radio-frequency quadrupole (RFQ) accelerator. In addition to the operational experiences in achieving this status, some of the modifications of the vacuum system, cooling system, and rf structure are discussed. Preliminary beam-characterization results are presented. 10 refs., 8 figs

  7. Cw rf operation of the FMIT RFQ

    International Nuclear Information System (INIS)

    Fazio, M.V.; Brandeberry, F.E.

    1985-01-01

    The 80-MHz RFQ for the Fusion Materials Irradiation Test Facility prototype accelerator has been rf conditioned for cw operation to the design field level of 17.5 MV/m (1.68 x Kilpatrick limit). Experimental results and operating experience will be discussed

  8. Properties of high current RFQ injectors

    Energy Technology Data Exchange (ETDEWEB)

    Schempp, A.; Goethe, J.W. [Frankfurt Univ. (Germany). Inst. fuer Angewandte Physik

    1996-12-31

    RFQ linacs are efficient, compact low energy ion structures, which have found numerous applications. They use electrical rf focusing and can capture, bunch and transmit high current ion beams. Some recent development and new projects like a heavy ion injectors for a cyclotron, and the status of the work on high current high duty factor RFQs will be discussed. (author) 2 refs.

  9. Reducing longitudinal emittance growth in RFQ accelerators

    International Nuclear Information System (INIS)

    Koscielniak, S.

    1994-08-01

    Bunching and capture of a monochromatic beam into an rf bucket inevitably lead to substantial emittance growth through the mechanisms of filamentation and non-adiabatic variation of parameters. We describe a three step strategy for minimizing this growth, based on a clear understanding of the non-linear beam dynamics, and apply to acceleration of heavy ions with Z/A = 1/60 (and initial kinetic energy 60 keV/u) in a radio frequency quadrupole (RFQ) operating at 25 MHz. We also describe a scheme, to further reduce the emittance, based upon the use of an external RFQ-type prebuncher before the main accelerator. The external unit permits the bunching voltage to be reduced, to inject into a moving bucket, and to reduce the structure length. (author). 7 refs., 6 figs

  10. Commissioning of the Ground Test Accelerator RFQ

    International Nuclear Information System (INIS)

    Johnson, K.F.; Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Brown, S.; Connolly, R.; Garnett, R.; Gilpatrick, J.D.; Guy, F.W.; Ingalls, W.B.; Little, C.; Lohson, R.A.; Lloyd, S.; Neuschaefer, G.; Power, J.; Saadatmand, K.; Sandoval, D.P.; Stevens, R.R.; Vaughn, G.; Wadlinger, E.A.; Weiss, R.; Yuan, V.

    1992-01-01

    The Ground Test Accelerator (GTA) has the objective of verifying much of the technology (physics and engineering) required for producing high-brightness, high-current H - beams. GTA commissioning is staged to verify the beam dynamics design of each major accelerator component as it is brought on-line. The commissioning stages are the 35 key H - injector, the 2.5 MeV Radio Frequency Quadrupole (RFQ), the Intertank Matching Section (IMS), the 3.2 MeV first 2βγ Drift Tube Linac (DTL-1) module, the 8.7 MeV 2βγ DTL (modules 1--5), and the 24 MeV GTA; all 10 DTL modules. Commissioning results from the RFQ beam experiments will be presented along with comparisons to simulations

  11. Commissioning of the ground test accelerator RFQ

    International Nuclear Information System (INIS)

    Johnson, K.F.; Sander, O.R.; Atkins, W.H.; Bolme, G.O.; Brown, S.; Garnott, R.; Gilpatrick, J.D.; Guy, F.W.; Ingalls, W.B.; Little, C.; Lohsen, R.A.; Lloyd, S.; Neuschaefer, G.; Power, J.; Sandoval, D.P.; Saadatmand, K.; Stevens, R.R.Jr.; Vaughn, G.; Wadlinger, E.A.; Yuan, V.; Connolly, R.; Weiss, R.

    1992-01-01

    The Ground Test Accelerator (GTA) has the objective of verifying much of the technology (physics and engineering) required for producing high-brightness, high-current H - beams. GTA commissioning is staged to verify the beam dynamics design of each major accelerator component as it is brought on line. The commissioning stages are the 35-keV H - injector, the 2.5-MeV radio-frequency quadrupole (RFQ), the intertank matching section (IMS), the 3.2-MeV first 2-βλ drift tube linac (DTL-1) module, the 8.7-MeV 2-βλDTL (modules 1-5), and the 24-MeV GTA (all 10 DTL modules). Commissioning results from the RFQ beam experiments are presented along with comparisons with simulations. (Author) 8 refs., 9 figs

  12. SSCL RFQ-DTL Matching Section instrumentation

    International Nuclear Information System (INIS)

    Datte, P.; Aielo, R.; Hayworth, M.

    1993-11-01

    A description of the SSCL RFQ-DTL Matching Section instrumentation is presented with emphasis on design issues and early instrumentation commissioning results. The H - beam energy through the RFQ-DTL matching section is 2.5 MeV, the beam current is 27 mA with a pulse width of 35 Its. The typical beam diameter is 3 mm. The instrumentation consists of three beam position monitors (BPM), a wire scanner, beam loss monitors (BLM), a slit and collector emittance measurement unit (EMU), a current toroid, and a Faraday cup. The instruments were designed to accommodate high current densities, have a large dynamic range with moderate bandwidths, and fit congested spaces

  13. Transmission efficiency measurement at the FNAL 4-rod RFQ

    Energy Technology Data Exchange (ETDEWEB)

    Carneiro, J. P. [Fermilab; Garcia, F. G. [Fermilab; Ostiguy, J. F. [Fermilab; Saini, A. [Fermilab; Zwaska, R. [Fermilab; Mustapha, B. [Argonne; Ostroumov, P. [Argonne

    2014-12-01

    This paper presents measurements of the beam transmission performed on the 4-rod RFQ currently under operation at Fermilab. The beam current has been measured at the RFQ exit as a function of the magnetic field strength in the two LEBT solenoids. This measurement is compared with scans performed on the FermiGrid with the beam dynamics code TRACK. A particular attention is given to the impact, on the RFQ beam transmission, of the space-charge neutralization in the LEBT.

  14. Radio-frequency quadrupole, RFQ-1

    CERN Multimedia

    Photographic Service

    1983-01-01

    Inner structure of RFQ-1, which replaced in 1983 the Cockcroft-Walton preinjector of Linac 1. It accelerated protons and negative hydrogen ions to 520 keV during the period that Linac 1 was used for LEAR (1981-1996). The precision-machined modulated electrodes ("vanes") are shaped to first bunch the dc-beam from the ion source and then provide simultaneous acceleration and focusing of the beam.

  15. A light ion four rod RFQ injector

    International Nuclear Information System (INIS)

    Schempp, A.; Ferch, M.; Klein, H.

    1987-01-01

    The four-rod RFQ has been developed in Frankfurt as an alternative solution for ion injectors. A 202 MHz resonator has been built with design parameters taken from the HERA injector (18keV-750keV, 20mA H - ). Properties of this structure are described and applications as light ion accelerator for particles from an EBIS ion source are discussed

  16. Evaluation of RF properties by orifice design for IFMIF RFQ

    International Nuclear Information System (INIS)

    Maebara, Sunao; Sugimoto, Masayoshi

    2005-03-01

    Orifices for the IFMIF RFQ have been designed and fabricated, and RF properties have been evaluated by a network analyzer. The designed orifices were installed into a vacuum port of the 1.1m-long RFQ mock-up module, and the resonant frequency and the phase difference between cavities were measured for a quadrupole operation mode of TE 210 . It was found that the RF properties are not affected on condition that slit direction with the same direction of current flow at the RFQ wall. Orifice conductance from 0.22 to 0.25 m 3 /sec by nitrogen conversion at room temperature was designed, and an ultimate pressure level of 5x10 -7 [Pa] was evaluated for the 4.1m-long central module for the IFMIF RFQ. It was concluded that the designed orifices are effective for RF properties and vacuum conductance in the IFMIF RFQ. (author)

  17. Comparison of simulation with experiment in an RFQ

    International Nuclear Information System (INIS)

    Boicourt, G.P.; Sander, O.R.; Wangler, T.P.

    1985-01-01

    The accelerator test stand (ATS) RFQ has provided an opportunity to compare the predictions of the RFQ beam-dynamics code PARMTEQ with actual operation of an RFQ. For this comparison, the code was adapted to simulate the measured operation parameters, which are somewhat different from those of the ideal design. A Monte Carlo code was written to provide input to PARMTEQ, based on measured input beam distributions. With these refinements, the code has given results that are in good agreement with measurements and has provided information leading to an explanation of an unexpected set of measurements. This paper describes the method used to generate a pseudo particle beam based on the measured transverse properties of the RFQ input beam and describes some of the comparisons between simulation and experiment. An explanation is provided for the energy-spectrum structure observed in the RFQ output beam during low-voltage operation. 3 refs., 7 figs

  18. Radio-frequency quadrupole, RFQ-1

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Inner structure of RFQ-1, which in 1984 replaced the Cockcroft-Walton preinjector of Linac 1. It accelerated protons and negative hydrogen-ions to 520 keV during the period that Linac 1 was used for LEAR (1981-1996). The precision-machined modulated electrodes ("vanes") are shaped to first bunch the dc-beam from the ion source and then provide simultaneous acceleration and focusing of the beam. See also 8303511. For pictures of pre-installation RF tests, see 8202557, 8202558, 8202559.

  19. A superconducting RFQ for an ECR injector

    International Nuclear Information System (INIS)

    Ben-Zvi, I.

    1988-01-01

    The beam dynamics and resonator properties of a superconducting radio-frequency quadrupole (RFQ) for heavy ions are discussed. The motivation is its use as a very low velocity section following an electron cyclotron resonance (ECR) source for injection into a superconducting heavy-ion linac. The constraints on the design and performance of this accelerating structure are presented. Expressions for a limiting stable phase angle and longitudinal and transverse acceptance are derived. A numerical example is given, using the SUNYLAC linac at Sony Stony Brook. Beam-dynamics calculations with PARMTEQ are reported, verifying the theoretical beam-dynamics calculations. (author) 12 refs., 1 tab

  20. Operation of a 473 MHz four-rod cavity RFQ

    International Nuclear Information System (INIS)

    Kazimi, R.; Huson, F.R.; Mackay, W.W.; Meitzler, C.R.

    1992-01-01

    We have constructed a new type of four-rod Radio Frequency Quadrupole to operate at 473 MHz. Four-rod structures have not previously been built for such a high frequency. The RFQ is designed to accelerate 10 mA of H - ions from 30 keV to 0.5 MeV. The rf measurements and beam test of the RFQ have been performed successfully. Here we present operational results of the RFQ system including measurements of the beam current, the required rf power, energy, energy spread, and emittance. (Author) 8 refs., 6 figs., 2 tabs

  1. Oxygen ion source and RFQ for Linac 1

    CERN Multimedia

    Photographic Service

    1986-01-01

    As injector to the PS Booster, Linac 1 was replaced by Linac 2 in 1980. It continued to be used for the acceleration of oxygen and sulfur ions. In 1984, its Cockcroft-Walton preinjector was replaced by an RFQ. In the foreground at the right is the oxygen ion source. A 90 deg bending magnet selects O6+ ions which are preaccelerated in an RFQ and enter Linac 1, at the far left. In the background is the proton and negative hydrogen ion source, followed by the 520 keV RFQ-1 and a bending magnet towards the entrance of Linac 1.

  2. Preliminary physical design of 7 MeV proton RFQ for the accelerator driven-energy system

    International Nuclear Information System (INIS)

    Luo Zihua

    2000-01-01

    The preliminary physical design of 7 MeV proton RFQ for the ADS (Accelerator Driven-energy System) is briefly described. The design features and the basic parameters and the design version of the RFQ are discussed. The matches between IS and RFQ and between RFQ and CCDTL/DTL are also discussed. The ideas of research for the RFQ are presented

  3. Coaxial short pulsed laser

    Science.gov (United States)

    Nelson, M.A.; Davies, T.J.

    1975-08-01

    This invention relates to a laser system of rugged design suitable for use in a field environment. The laser itself is of coaxial design with a solid potting material filling the space between components. A reservoir is employed to provide a gas lasing medium between an electrode pair, each of which is connected to one of the coaxial conductors. (auth)

  4. Feasibility studies of RFQ based 14C accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Guo Zhiyu; Liu Kexin; Yan Xueqing; Xie Yi; Fang Jiaxun; Chen Jiaer

    2007-01-01

    Electrostatic accelerators with terminal voltage less than 1 MeV have been successfully used for 14 C AMS. This contribution shows that a small RFQ accelerator may also be suitable for AMS 14 C measurements. A well-designed RFQ accelerator can realize a low energy spread and high isotopic selection with a length of less than 1 m and reasonable power consumption. Compared with small tandem accelerators, a RFQ does not need isolation gas and can accept much higher beam currents. Its stripper would be at ground potential and there would be no further acceleration after stripping, so the background from charge exchange processes should be lower. The RFQ design and system are described

  5. APT/LEDA RFQ and support frame structural analysis

    International Nuclear Information System (INIS)

    Ellis, S.

    1997-01-01

    This report documents structural analysis of the Accelerator Production of Tritium Low Energy Demonstration Accelerator (APT/LEDA) Radio Frequency Quadrupole (RFQ) accelerator structure and its associated support frame. This work was conducted for the Department of Energy in support of the APT/LEDA. Structural analysis of the RFQ was performed to quantify stress levels and deflections due to both vacuum loading and gravity loading. This analysis also verified the proposed support scheme geometry and quantified interface loads. This analysis also determined the necessary stiffness and strength requirements of the RFQ support frame verifying the conceptual design geometry and allowing specification of individual frame elements. Complete structural analysis of the frame was completed subsequently. This report details structural analysis of the RFQ assembly with regard to gravity and vacuum loads only. Thermally induced stresses from the Radio Frequency (RF) surface resistance heating were not considered

  6. Pulsed beam tests at the SANAEM RFQ beamline

    Science.gov (United States)

    Turemen, G.; Akgun, Y.; Alacakir, A.; Kilic, I.; Yasatekin, B.; Ergenlik, E.; Ogur, S.; Sunar, E.; Yildiz, V.; Ahiska, F.; Cicek, E.; Unel, G.

    2017-07-01

    A proton beamline consisting of an inductively coupled plasma (ICP) source, two solenoid magnets, two steerer magnets and a radio frequency quadrupole (RFQ) is developed at the Turkish Atomic Energy Authority’s (TAEA) Saraykoy Nuclear Research and Training Center (SNRTC-SANAEM) in Ankara. In Q4 of 2016, the RFQ was installed in the beamline. The high power tests of the RF power supply and the RF transmission line were done successfully. The high power RF conditioning of the RFQ was performed recently. The 13.56 MHz ICP source was tested in two different conditions, CW and pulsed. The characterization of the proton beam was done with ACCTs, Faraday cups and a pepper-pot emittance meter. Beam transverse emittance was measured in between the two solenoids of the LEBT. The measured beam is then reconstructed at the entrance of the RFQ by using computer simulations to determine the optimum solenoid currents for acceptance matching of the beam. This paper will introduce the pulsed beam test results at the SANAEM RFQ beamline. In addition, the high power RF conditioning of the RFQ will be discussed.

  7. Coaxial foilless diode

    OpenAIRE

    Long Kong; QingXiang Liu; XiangQiang Li; ShaoMeng Wang

    2014-01-01

    A kind of coaxial foilless diode is proposed in this paper, with the structure model and operating principle of the diode are given. The current-voltage relation of the coaxial foilless diode and the effects of structure parameters on the relation are studied by simulation. By solving the electron motion equation, the beam deviation characteristic in the presence of external magnetic field in transmission process is analyzed, and the relationship between transverse misalignment with diode par...

  8. Operational parameters of a 2.0-MeV RFQ linac

    International Nuclear Information System (INIS)

    Sander, O.R.; Purser, F.O.; Rusthoi, D.P.

    1984-01-01

    After extensive upgrading, our radio-frequency quadrupole (RFQ) linac is again installed on the accelerator test stand (ATS). The measured parameters of the RFQ, such as the output transverse emittance, transmitted beam, average energy, and energy spread is presented

  9. RFQ Cooler and Buncher (and beam line section associated)

    CERN Document Server

    Podadera-Aliseda, I

    2003-01-01

    Developing a new RFQ cooler and buncher for ISOLDE. Such a device combines an energy loss in buffer gas atom-ion collisions with confinement provided by RF-field in transverse plane. Optional confinement in longitudinal direction is provided by static potential dwell. Then, an improvement of the beam line is achieved for all the experiments at ISOLDE. The RFQ operates inside a high voltage cage of 60 kV, and with a system of turbomulecular pumps both to keep the high vacuum before/after the RFQ and to keep a low pressure (around 0,1 mbar) inside the RFQ. The project is to be thought not only as a mechanical design and construction project, unless as a project of research and development, since it is about improving (operationally and technically) the existing RFQ cooler and buncher placed around the world. Due to ion optical reasons whole beam line section has to be redesigned and constructed as a part of this project.

  10. Transmission line matching simulation for 350 MHz RF driver for 400 KeV (deuterium) RFQ based 14 MeV neutron source

    International Nuclear Information System (INIS)

    Sharma, Sonal; Pande, Manjiri; Handu, V.K.

    2009-01-01

    A 60 KW, 350 MHz tetrode based high power RF system is being developed for 400 KeV RFQ based 14 MeV neutron generator in Bhabha Atomic Research Centre to study physics of coupled neutron sources and subcritical assembly. This RF system requires a 2.5 kW RF driver which is being designed by using tetrode TH-393. At such high frequency i.e. 350 MHz, lumped components are not practically useful due to radiation losses. Therefore, techniques such as coaxial line with stub tuning are preferred, which minimizes these losses. Simulation of two such stub tuning based matched coaxial lines at the input and output of the tube has been done by using CST studio. CST STUDIO is a special tool for the 3D EM simulation of high frequency components

  11. Parametric thermal analysis of 75 MHz heavy ion RFQ

    International Nuclear Information System (INIS)

    Mishra, N.K.; Mehrotra, N.; Verma, V.; Gupta, A.K.; Bhagwat, P.V.

    2015-01-01

    An ECR based Heavy Ion Accelerator comprising of a superconducting Electron Cyclotron Resonance (ECR) Ion Source, normal conducting RFQ (Radio Frequency Quadrupole) and superconducting Niobium resonators is being developed at BARC under XII plan. A state-of-the-art 18 GHz superconducting ECR ion source (PK-ISIS) jointly configured with Pantechnik, France is operational at Van-de-Graaff, BARC. The electromagnetic design of the improved version of 75 MHz heavy ion RFQ has been reported earlier. The previous thermal study of 51 cm RFQ model showed large temperature variation axially along the vane tip. A new coolant flow scheme has been worked out to optimize the axial temperature gradient. In this paper the thermal analysis including parametric study of coolant flow rates and inlet temperature variation will be presented. (author)

  12. Resonant Control for Fermilab's PXIE RFQ

    Energy Technology Data Exchange (ETDEWEB)

    Bowring, Daniel [Fermilab; Biedron, Sandra [Colorado State U., Fort Collins; Chase, Brian [Fermilab; Czajkowski, Jerzy [Fermilab; Edelen, Auralee [Colorado State U., Fort Collins; Edelen, Jonathan [Fermilab; Milton, Stephen [Colorado State U., Fort Collins; Nicklaus, Dennis [Fermilab; Steimel, Jim [Fermilab; Zuchnik, Thomas [Fermilab

    2016-06-01

    The RFQ for Fermilab's PXIE test program is designed to accelerate a < 10 mA H⁻ CW beam to 2.1 MeV. The RFQ has a four-vane design, with four modules brazed together for a total of 4.45 m in length. The RF power required is < 130 kW at 162.5 MHz. A 3 kHz limit on the maximum allowable frequency error is imposed by the RF amplifiers. This frequency constraint must be managed entirely through differential cooling of the RFQ's vanes and outer body and associated material expansion. Simulations indicate that the body and vane coolant temperature should be controlled to within 0.1 degrees C. We present the design of the cooling network and the resonant control algorithm for this structure, as well as results from initial operation.

  13. The RF inlet of the RFQ of IPHI

    International Nuclear Information System (INIS)

    Piquet, O.; Desmons, M.; France, A.

    2005-02-01

    The power supply of the radio frequency quadrupole (RFQ) requires a new type of transition between the WR2300 waveguide and the RFQ cavity. This transition is an impedance transformer with a bottleneck shape that allows the transmission of the power along a 3.7 MHz broad pass-band centered on an operating frequency of 352.2 MHz. This design has allowed us to separate the adjustment of the transition from the setting of the coupling holes in the cavity wall. This whole transition has been tested on the RFQ mockup in order to optimize the diameter of the coupling holes. It appears that an important point for a good coupling is to be sure of good RF contacts between the different components of the transition device. (A.C.)

  14. BEAR RFQ-beam experiment aboard a rocket

    International Nuclear Information System (INIS)

    Schrage, D.; Young, L.; Campbell, B.; Billen, J.H.; Stovall, J.; Martinez, F.; Clark, W.; Bolme, G.; Gibbs, S.; King, D.; O'Shea, P.; Butler, T.; Rathke, J.; Micich, R.; Rose, J.; Richter, R.; Rosato, G.

    1989-01-01

    Los Alamos National Laboratory, Grumman, and GAR Electroformers have completed the design and fabrication of an electroformed RFQ for the BEAR (beam experiments aboard a rocket) project. The design of this 1 m long, lightweight (< 55 kg accelerator incorporates four aluminum vane/cavity quadrants joined by an electroforming process. With the vane and cavity fabricated as a monolithic structure, there are no mechanical rf, vacuum or structural joints. The completed BEAR RFQ has successfully passed flight qualification and beam transport tests in preparation for the flight, which is scheduled for March 1989. (orig.)

  15. Voltage-breakdown testing for an RFQ structure

    International Nuclear Information System (INIS)

    Williams, S.W.; DePaula, R.F.; Keffeler, D.R.; Rodenz, G.R.

    1981-01-01

    Designs for Radio Frequency Quadrupole (RFQ) accelerators of reasonable length require operation with surface fields above the threshold of Kilpatrick's Sparking Criterion. A cavity was designed using SUPERFISH to test the validity of this criterion and to determine operating limits for the Los Alamos Proof-of-Princple (POP) RFQ. The testing was done near 420 MHz, with varying qualities of surface finish on the electrodes. The experimental set-up and procedure are described, as are the data and results. A method of calibrating the test is presented

  16. BEAR RFQ-beam experiment aboard a rocket

    Energy Technology Data Exchange (ETDEWEB)

    Schrage, D.; Young, L.; Campbell, B.; Billen, J.H.; Stovall, J.; Martinez, F.; Clark, W.; Bolme, G.; Gibbs, S.; King, D.; O' Shea, P.; Butler, T. (Los Alamos National Lab., NM (USA)); Rathke, J.; Micich, R.; Rose, J. (Grumman Space Systems, Bethpage, NY (USA)); Richter, R.; Rosato, G. (GAR Electroformers, Danbury, CT (USA))

    1989-04-01

    Los Alamos National Laboratory, Grumman, and GAR Electroformers have completed the design and fabrication of an electroformed RFQ for the BEAR (beam experiments aboard a rocket) project. The design of this 1 m long, lightweight < 55 kg accelerator incorporates four aluminum vane/cavity quadrants joined by an electroforming process. With the vane and cavity fabricated as a monolithic structure, there are no mechanical rf, vacuum or structural joints. The completed BEAR RFQ has successfully passed flight qualification and beam transport tests in preparation for the flight, which is scheduled for March 1989. (orig.).

  17. Study of influence of radial matcher section end shape on RFQ cavity frequency

    International Nuclear Information System (INIS)

    Zhang Zhouli; He Yuan; Zhang Bin; Shi Aimin; Pan Gang; Du Xiaonan; Sun Liepeng; Li Derun

    2014-01-01

    To investigate the feasibility of using a form cutter to machine the Radial Matcher Section (RMS) of the Radio Frequency Quadrupole (RFQ) for the Accelerator Driven System (ADS) project at Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS), the influence of RMS end shape on the RFQ cavity frequency is studied. The results indicate that using a form cutter to machine the RMS of an RFQ will indeed influence the cavity frequency. The RMS end shape will give more influence to a shorter RFQ cavity. For the 4.2 m ADS RFQ, the influence is negligible, which means that a form cutter can be used to machine the RMS. (authors)

  18. Coaxial foilless diode

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Long; Liu, QingXiang; Li, XiangQiang; Wang, ShaoMeng [College of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031 (China)

    2014-05-15

    A kind of coaxial foilless diode is proposed in this paper, with the structure model and operating principle of the diode are given. The current-voltage relation of the coaxial foilless diode and the effects of structure parameters on the relation are studied by simulation. By solving the electron motion equation, the beam deviation characteristic in the presence of external magnetic field in transmission process is analyzed, and the relationship between transverse misalignment with diode parameters is obtained. These results should be of interest to the area of generation and propagation of radial beam for application of generating high power microwaves.

  19. Coaxial foilless diode

    Directory of Open Access Journals (Sweden)

    Long Kong

    2014-05-01

    Full Text Available A kind of coaxial foilless diode is proposed in this paper, with the structure model and operating principle of the diode are given. The current-voltage relation of the coaxial foilless diode and the effects of structure parameters on the relation are studied by simulation. By solving the electron motion equation, the beam deviation characteristic in the presence of external magnetic field in transmission process is analyzed, and the relationship between transverse misalignment with diode parameters is obtained. These results should be of interest to the area of generation and propagation of radial beam for application of generating high power microwaves.

  20. Coaxial pulse matching transformer

    International Nuclear Information System (INIS)

    Ledenev, V.V.; Khimenko, L.T.

    1986-01-01

    This paper describes a coaxial pulse matching transformer with comparatively simple design, increased mechanical strength, and low stray inductance. The transformer design makes it easy to change the turns ratio. The circuit of the device and an expression for the current multiplication factor are presented; experiments confirm the efficiency of the transformer. Apparatus with a coaxial transformer for producing high-power pulsed magnetic fields is designed (current pulses of 1-10 MA into a load and a natural frequency of 100 kHz)

  1. Coaxial transmission line - Equalization

    International Nuclear Information System (INIS)

    Bonnerue, J.L.; Fremont, Jacques; Haubtmann, Jack; Pillon, Gerard.

    1981-09-01

    The transmission of electrical signal through a coaxial line is not perfect and signal distortions are increased as much as the frequency spectrum is extended. We have designed and achieved passive filters (named equalizers) with transfer functions which are inverse of coaxial transfer functions. Doing so our attempt is to avoid definitive loss of information in the recorded data. The main feature of our equalization method lies in the fact it could be either an electrical or a numerical correction or both of them. Some examples in the use of this technique are also proposed [fr

  2. Improvement of frequency variability of the folded-coaxial radio-frequency quadrupole linac by installing a detachable stem in its resonator

    International Nuclear Information System (INIS)

    Kamigaito, Osamu; Goto, Akira; Miyazawa, Yoshitoshi; Chiba, Toshiya; Hemmi, Masatake; Kase, Masayuki; Kohara, Shigeo; Yano, Yasushige

    1995-01-01

    The beneficial effect of adding a detachable stem to the folded-coaxial resonator of the frequency-variable radio-frequency quadrupole (RFQ) linac previously reported was examined experimentally using a half-scale model as well as by numerical analyses. As a result, this simple modification was found to extend variable frequencies to a high region without increase of rf power consumption. (author)

  3. Commissioning report on the RFQ of the HITRAP decelerator

    Energy Technology Data Exchange (ETDEWEB)

    Maier, Michael; Herfurth, Frank; Yaramishev, Stepan; Neidherr, Dennis; Vorobyev, Gleb; Kotovskiy, Nikita [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Repnow, Roland [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)

    2012-07-01

    Commissioning of the HITRAP decelerator behind the experimental storage ring (ESR) has been difficult and not fully successful yet. According to simulations the present RFQ design requires beam with an input energy of 530 keV/u. This is above the limit of the IH decelerator which has been designed for 500 keV/u output energy. In order to verify the simulation results the RFQ has been set up together with a test bench behind a pelletron accelerator at the Max Planck Institute for nuclear physics in Heidelberg. This pelletron provides DC beam with A/q<3 in the desired energy range of 450-550 keV/u. This setup allows for a rapid scan through this otherwise difficult to reach parameter space. Additionally it will serve a second time as a commissioning setup for the next RFQ electrode design matched to the IH output energy. In this contribution the simulations and the experimental results of this test are compared as well as a first design study for a new RFQ decelerator structure is presented.

  4. High power coaxial ubitron

    Science.gov (United States)

    Balkcum, Adam J.

    In the ubitron, also known as the free electron laser, high power coherent radiation is generated from the interaction of an undulating electron beam with an electromagnetic signal and a static periodic magnetic wiggler field. These devices have experimentally produced high power spanning the microwave to x-ray regimes. Potential applications range from microwave radar to the study of solid state material properties. In this dissertation, the efficient production of high power microwaves (HPM) is investigated for a ubitron employing a coaxial circuit and wiggler. Designs for the particular applications of an advanced high gradient linear accelerator driver and a directed energy source are presented. The coaxial ubitron is inherently suited for the production of HPM. It utilizes an annular electron beam to drive the low loss, RF breakdown resistant TE01 mode of a large coaxial circuit. The device's large cross-sectional area greatly reduces RF wall heat loading and the current density loading at the cathode required to produce the moderate energy (500 keV) but high current (1-10 kA) annular electron beam. Focusing and wiggling of the beam is achieved using coaxial annular periodic permanent magnet (PPM) stacks without a solenoidal guide magnetic field. This wiggler configuration is compact, efficient and can propagate the multi-kiloampere electron beams required for many HPM applications. The coaxial PPM ubitron in a traveling wave amplifier, cavity oscillator and klystron configuration is investigated using linear theory and simulation codes. A condition for the dc electron beam stability in the coaxial wiggler is derived and verified using the 2-1/2 dimensional particle-in-cell code, MAGIC. New linear theories for the cavity start-oscillation current and gain in a klystron are derived. A self-consistent nonlinear theory for the ubitron-TWT and a new nonlinear theory for the ubitron oscillator are presented. These form the basis for simulation codes which, along

  5. Embryo splitting

    Directory of Open Access Journals (Sweden)

    Karl Illmensee

    2010-04-01

    Full Text Available Mammalian embryo splitting has successfully been established in farm animals. Embryo splitting is safely and efficiently used for assisted reproduction in several livestock species. In the mouse, efficient embryo splitting as well as single blastomere cloning have been developed in this animal system. In nonhuman primates embryo splitting has resulted in several pregnancies. Human embryo splitting has been reported recently. Microsurgical embryo splitting under Institutional Review Board approval has been carried out to determine its efficiency for blastocyst development. Embryo splitting at the 6–8 cell stage provided a much higher developmental efficiency compared to splitting at the 2–5 cell stage. Embryo splitting may be advantageous for providing additional embryos to be cryopreserved and for patients with low response to hormonal stimulation in assisted reproduction programs. Social and ethical issues concerning embryo splitting are included regarding ethics committee guidelines. Prognostic perspectives are presented for human embryo splitting in reproductive medicine.

  6. CO-AXIAL DISCHARGES

    Science.gov (United States)

    Luce, J.S.; Smith, L.P.

    1960-11-22

    A method and apparatus are given for producing coaxial arc discharges in an evacuated enclosure and within a strong, confining magnetic field. The arcs are maintained at a high potential difference. Electrons will diffuse to the more positive arc from the negative arc, and positive ions will diffuse from the more positive arc to the negative arc. Coaxial arc discharges have the advantage that ions which return to strike the positive arc discharge will lose no energy since they do not strike a solid wall or electrode. Those discharges are useful in confining an ionized plasma between the discharges, and have the advantage of preventing impurities from the walls of the enclosure from entering ihe plasma area because of the arc barrier set up bv the cylindrical outer arc.

  7. The Brown-Servranckx matching transformer for simultaneous RFQ to DTL H+ and H- matching

    International Nuclear Information System (INIS)

    Wadlinger, E.A.; Garnett, R.W.

    1996-01-01

    The issue involved in the simultaneous matching of H + and H - beams between an RFQ and DTL lies in the fact that both beams experience the same electric-field forces at a given position in the RFQ. Hence, the two beams are focused to the same correlation. However, matching to a DTL requires correlation of the opposite sign. The Brown-Servranckx quarter-wave (λ / 4) matching transformer system, which requires four quadrupoles, provides a method to simultaneously match H + and H - beams between an RFQ and a DTL. The method requires the use of a special RFQ section to obtain the Twiss parameter conditions β x = β y and α x = α y = 0 at the exit of the RFQ. This matching between the RFQ and DTL is described. (author)

  8. The Brown-Servranckx matching transformer for simultaneous RFQ to DTL H+ and H- matching

    International Nuclear Information System (INIS)

    Wadlinger, E.A.; Garnett, R.W.

    1996-01-01

    The issue involved in simultaneous matching of H + and H - beams between an RFQ and DTL lies in the fact that both beams experience the same electric-field forces at a given position in the RFQ. Hence, the two beams are focused to the same correlation. However, matching to a DTL requires correlation of the opposite sign. The Brown-Servranckx quarter-wave (λ/4) matching transformer system, which requires four quadrupoles, provides a method to simultaneously match H + and H - beams between an RFQ and a DTL. The method requires the use of a special RFQ section to obtain the Twiss parameter conditions β x =β y and α x =α y =0 at the exit of the RFQ. This matching between the RFQ and DTL is described

  9. Development of C{sup 6+} laser ion source and RFQ linac for carbon ion radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Sako, T., E-mail: takayuki1.sako@toshiba.co.jp; Yamaguchi, A.; Sato, K. [Toshiba Corporation, Yokohama 235-8522 (Japan); Goto, A.; Iwai, T.; Nayuki, T.; Nemoto, K.; Kayama, T. [Cancer Research Center, Yamagata University Faculty of Medicine, Yamagata 990-9585 (Japan); Takeuchi, T. [Accelerator Engineering Corporation, Chiba 263-0043 (Japan)

    2016-02-15

    A prototype C{sup 6+} injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4.

  10. Development of C6+ laser ion source and RFQ linac for carbon ion radiotherapy

    Science.gov (United States)

    Sako, T.; Yamaguchi, A.; Sato, K.; Goto, A.; Iwai, T.; Nayuki, T.; Nemoto, K.; Kayama, T.; Takeuchi, T.

    2016-02-01

    A prototype C6+ injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4.

  11. Development of C⁶⁺ laser ion source and RFQ linac for carbon ion radiotherapy.

    Science.gov (United States)

    Sako, T; Yamaguchi, A; Sato, K; Goto, A; Iwai, T; Nayuki, T; Nemoto, K; Kayama, T; Takeuchi, T

    2016-02-01

    A prototype C(6+) injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4.

  12. Development of C6+ laser ion source and RFQ linac for carbon ion radiotherapy

    International Nuclear Information System (INIS)

    Sako, T.; Yamaguchi, A.; Sato, K.; Goto, A.; Iwai, T.; Nayuki, T.; Nemoto, K.; Kayama, T.; Takeuchi, T.

    2016-01-01

    A prototype C 6+ injector using a laser ion source has been developed for a compact synchrotron dedicated to carbon ion radiotherapy. The injector consists of a laser ion source and a 4-vane radio-frequency quadrupole (RFQ) linac. Ion beams are extracted from plasma and directly injected into the RFQ. A solenoid guides the low-energy beams into the RFQ. The RFQ is designed to accelerate high-intensity pulsed beams. A structure of monolithic vanes and cavities is adopted to reduce its power consumption. In beam acceleration tests, a solenoidal magnetic field set between the laser ion source and the RFQ helped increase both the peak currents before and after the RFQ by a factor of 4

  13. Redesign of CERN LINAC3 RFQ for Lead 29+

    CERN Document Server

    Benedetti, Stefano; Lallement, Jean-Baptiste; Lombardi, Alessandra; CERN. Geneva. ATS Department

    2018-01-01

    CERN Linac3 is at the heart of the CERN Heavy Ion Facility, providing 4.2 MeV/u ion beams to the Low Energy Ion Ring (LEIR). It mostly accelerates 208Pb29+, though in recent years runs were performed with 40Ar11+ and 129Xe22+, in view of the raising interest of the physics community towards lighter ions experiments. In the framework of the LHC Injectors Upgrade (LIU) project, measurements and beam dynamics simulations showed that a transmission bottleneck of Linac3 is represented by the RFQ. As this accelerator was originally designed for 208Pb25+, the lower beam rigidity of the heavy ions currently in used – and planned to be used – permits a redesign of the RFQ aimed at increasing its transverse acceptance, and thus the transmitted beam current. The methodology adopted and the results of this study are presented.

  14. Accuracy of the manufacture of electrodes for a 433 MHz RFQ

    International Nuclear Information System (INIS)

    Budtov, A.A.; Gruzdev, V.A.; Petrov, V.I.; Svistunov, Y.A.; Marinin, G.V.

    2006-01-01

    Analysis of the dependence of the accuracy of the interelectrode distance on the accuracy of electrode surface machining for a 433 MHz four-segment radio-frequency quadrupole (RFQ) resonator is reported. The aim of the research was to determine the requirements for measurement methods and machining of the RFQ segments. Analysis of particle capture into acceleration as a function of the electrode modulation amplitude at the RFQ input is discussed

  15. Accuracy of the manufacture of electrodes for a 433 MHz RFQ

    Energy Technology Data Exchange (ETDEWEB)

    Budtov, A.A. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (NIIEFA), Scientific Production Complex of Linear Accelerators and Cyclotrons (NPK LUTS), 196641 St. Petersburg (Russian Federation); Gruzdev, V.A. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (NIIEFA), Scientific Production Complex of Linear Accelerators and Cyclotrons (NPK LUTS), 196641 St. Petersburg (Russian Federation); Petrov, V.I. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (NIIEFA), Scientific Production Complex of Linear Accelerators and Cyclotrons (NPK LUTS), 196641 St. Petersburg (Russian Federation)]. E-mail: npkluts@niiefa.spb.su; Svistunov, Y.A. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (NIIEFA), Scientific Production Complex of Linear Accelerators and Cyclotrons (NPK LUTS), 196641 St. Petersburg (Russian Federation); Marinin, G.V. [Russian Technologies Ltd., 195030 St. Peterburg (Russian Federation)

    2006-03-01

    Analysis of the dependence of the accuracy of the interelectrode distance on the accuracy of electrode surface machining for a 433 MHz four-segment radio-frequency quadrupole (RFQ) resonator is reported. The aim of the research was to determine the requirements for measurement methods and machining of the RFQ segments. Analysis of particle capture into acceleration as a function of the electrode modulation amplitude at the RFQ input is discussed.

  16. Dipole stabilizer rods for 400 keV deuteron RFQ

    International Nuclear Information System (INIS)

    Sista, V.L.S. Rao; Srivastava, S.C.L.; Pande, Rajni; Roy, Shweta; Singh, P.

    2009-01-01

    In our 400 keV deuteron RFQ for neutron production, the destructive dipolar modes are very close to the required quadrupolar mode. In order to increase the spacing between the quadrupole and dipole modes the dipolar stabilizer rods (DSR's) are used. The design of the DSR's is done using the computer code CST Microwave studio. The variation of the quadrupole and dipolar mode frequencies with the radius and length of the DSR's are studied. (author)

  17. RF structure design of the China Material Irradiation Facility RFQ

    Science.gov (United States)

    Li, Chenxing; He, Yuan; Xu, Xianbo; Zhang, Zhouli; Wang, Fengfeng; Dou, Weiping; Wang, Zhijun; Wang, Tieshan

    2017-10-01

    The radio frequency structure design of the radio frequency quadrupole (RFQ) for the front end of China Material Irradiation Facility (CMIF), which is an accelerator based neutron irradiation facility for fusion reactor material qualification, has been completed. The RFQ is specified to accelerate 10 mA continuous deuteron beams from the energies of 20 keV/u to 1.5 MeV/u within the vane length of 5250 mm. The working frequency of the RFQ is selected to 162.5 MHz and the inter-vane voltage is set to 65 kV. Four-vane cavity type is selected and the cavity structure is designed drawing on the experience of China Initiative Accelerator Driven System (CIADS) Injector II RFQ. In order to reduce the azimuthal asymmetry of the field caused from errors in fabrication and assembly, a frequency separation between the working mode and its nearest dipole mode is reached to 17.66 MHz by utilizing 20 pairs of π-mode stabilizing loops (PISLs) distributed along the longitudinal direction with equal intervals. For the purpose of tuning, 100 slug tuners were introduced to compensate the errors caused by machining and assembly. In order to obtain a homogeneous electrical field distribution along cavity, vane cutbacks are introduced and output endplate is modified. Multi-physics study of the cavity with radio frequency power and water cooling is performed to obtain the water temperature tuning coefficients. Through comparing to the worldwide CW RFQs, it is indicated that the power density of the designed structure is moderate for operation under continuous wave (CW) mode.

  18. Simulations of injection optics for an RFQ cooler and buncher

    CERN Document Server

    Eronen, Tommi

    2002-01-01

    This report is about injection of ions to a new RFQ (which stands for a Radio Frequency Quadrupole) cooler & trap which will be built at ISOLDE, CERN. This device brings very good advantages to existing beamline - for instance, lower emittance in transversal plane and lower energy spread in longitudinal direction. It will be possible to bunch the beam. Lower emittance means that ions can be focused to smaller spot thus improving precision of measurements. For laser experiments bunched beam is much more useful compared to continuous beam. Bunch can be adjusted such that lasers are synchronized with the ion bunch thus increasing signal-to-background ratio. Using buffer gas cooling is also very cost effective and easy to operate - there is only a few tunable parameters in the RFQ. Buffer gas cooling is effective only if ions are much heavier than the buffer gas. Usually this is the case at ISOLDE. One of the most crucial part in the whole RFQ project is the injection. Because of the presence of buffer gas, R...

  19. Dipole compensation of the 176 MHz MYRRHA RFQ

    Energy Technology Data Exchange (ETDEWEB)

    Kuempel, Klaus; Podlech, Holger; Lenz, Christoph; Petry, Nils [IAP, University of Frankfurt, Frankfurt am Main (Germany); Bechtold, Alexander [NTG Neue Technologien GmbH und Co.KG, Gelnhausen (Germany); Zhang, Chuan [GSI Helmholtzzentrum, Darmstadt (Germany)

    2016-07-01

    The MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) Project is planned as an accelerator driven system (ADS) for the transmutation of long-living radioactive waste. For this project a cw 4-rod-RFQ with 176 MHz and a total length of about 4 m is required. It is supposed to accelerate protons from 30 keV up to 1.5 MeV*. One of the main tasks during the development of the RFQ is the very high reliability of the accelerator to limit the thermal stress inside the reactor. Another challenge was to compensate the dipole component of the MYRRHA-RFQ which is due to the design principle of 4-rod-RFQs. This dipole component is responsible for shifting the ideal beam axis from the geometrical center of the quadrupole downwards. Design studies with CST MICROWAVE STUDIO have shown that the dipole component can be almost completely compensated by widening the stems alternately so that the current paths of the lower electrodes are increased.

  20. Frequency Selective Properties of Coaxial Transmission Lines Loaded with Combined Artificial Inclusions

    Directory of Open Access Journals (Sweden)

    Francisco Falcone

    2014-01-01

    Full Text Available The properties of a modified coaxial transmission line by periodic inclusions will be discussed. The introduction of split ring resonators, conductor stubs, air gaps, and combination of these gives rise to new frequency selective properties, such as stopband or passband behavior, observable in planar as well as volumetric metamaterial structures. These results envisage new potential applications and implementation of devices in coaxial transmission line technology.

  1. Coaxial slow source

    International Nuclear Information System (INIS)

    Brooks, R.D.; Jarboe, T.R.

    1990-01-01

    Field reversed configurations (FRCs) are a class of compact toroid with not toroidal field. The field reversed theta pinch technique has been successfully used for formation of FRCs since their inception in 1958. In this method an initial bias field is produced. After ionization of the fill gas, the current in the coil is rapidly reversed producing the radial implosion of a current sheath. At the ends of the coil the reversed field lines rapidly tear and reconnect with the bias field lines until no more bias flux remains. At this point, vacuum reversed field accumulates around the configuration which contracts axially until an equilibrium is reached. When extrapolating the use of such a technique to reactor size plasmas two main shortcomings are found. First, the initial bias field, and hence flux in a given device, which can be reconnected to form the configuration is limited from above by destructive axial dynamics. Second, the voltages required to produce rapid current reversal in the coil are very large. Clearly, a low voltage formation technique without limitations on flux addition is desirable. The Coaxial Slow Source (CSS) device was designed to meet this need. It has two coaxial theta pinch coils. Coaxial coil geometry allows for the addition of as much magnetic flux to the annular plasma between them as can be generated inside the inner coil. Furthermore the device can be operated at charging voltages less than 10 kV and on resistive diffusion, rather than implosive time scales. The inner coil is a novel, concentric, helical design so as to allow it to be cantilevered on one end to permit translation of the plasma. Following translation off the inner coil the Annular Field Reversed Configuration would be re-formed as a true FRC. In this paper we investigate the formation process in the new parallel configuration., CSSP, in which the inner and outer coils are connected in parallel to the main capacitor bank

  2. Design of 57.5 MHz CW RFQ structure for the Rare Isotope ...

    Indian Academy of Sciences (India)

    The Rare Isotope Accelerator (RIA) facility includes a driver LINAC for production of 400 kW CW heavy-ion beams. The initial acceleration of heavy ions delivered from an ECR ion source can be effectively performed by a 57.5 MHz 4 m long RFQ. The principal specifications of the RFQ are: (1) formation of extremely low ...

  3. Chracterization of the beam from the RFQ of the PIP-II Injector Test

    Energy Technology Data Exchange (ETDEWEB)

    Shemyakin, A. [Fermilab; Carneiro. J.-P., Carneiro. J.-P. [Fermilab; Hanna, B. [Fermilab; Prost, L. [Fermilab; Saini, A. [Fermilab; Scarpine, V. [Fermilab; Sista, V. L.S. [Bhabha Atomic Res. Ctr.; Steimel, J. [Fermilab

    2017-05-01

    A 2.1 MeV, 10 mA CW RFQ has been installed and commissioned at the Fermilab’s test accelerator known as PIP-II Injector Test. This report describes the measure-ments of the beam properties after acceleration in the RFQ, including the energy and emittance.

  4. Laser spectroscopy of gallium isotopes using the ISCOOL RFQ cooler

    CERN Multimedia

    Blaum, K; Kowalska, M; Ware, T; Procter, T J

    2007-01-01

    We propose to study the radioisotopes of gallium (Z=31) by collinear laser spectroscopy using the ISCOOL RFQ ion cooler. The proposed measurements on $^{62-83}$Ga will span both neutron-deficient and neutron-rich isotopes. Of key interest is the suggested development of a proton-skin in the neutron-deficient isotopes. The isotope shifts measured by laser spectroscopy will be uniquely sensitive to this feature. The measurements will also provide a wealth of new information on the gallium nuclear spins, static moments and nuclear charge radii.

  5. Status Report on the 5 Mev Iphi RFQ

    OpenAIRE

    Ferdinand, R.; Beauvais, P-Y.; Duperrier, R.; France, A.; Gaiffier, J.; Lagniel, J-M.; Painchault, M.; Simoens, F.; CEA-Saclay; DSM-DAPNIA-SEA; Balleyguier, P.; Chatel, CEA-Bruyeres le; DAM

    2000-01-01

    A 5-MeV RFQ designed for a proton current up to 100-mA CW is now under construction as part of the High Intensity Proton Injector project (IPHI). Its computed transmission is greater than 99 %. The main goals of the project are to verify the accuracy of the design codes, to gain the know-how on fabrication, tuning procedures and operations, to measure the output beam characteristics in order to optimise the higher energy part of the linac, and to reach a high availability with minimum beam tr...

  6. RFQ Designs and Beam-Loss Distributions for IFMIF

    Energy Technology Data Exchange (ETDEWEB)

    Jameson, Robert A [ORNL

    2007-01-01

    The IFMIF 125 mA cw 40 MeV accelerators will set an intensity record. Minimization of particle loss along the accelerator is a top-level requirement and requires sophisticated design intimately relating the accelerated beam and the accelerator structure. Such design technique, based on the space-charge physics of linear accelerators (linacs), is used in this report in the development of conceptual designs for the Radio-Frequency-Quadrupole (RFQ) section of the IFMIF accelerators. Design comparisons are given for the IFMIF CDR Equipartitioned RFQ, a CDR Alternative RFQ, and new IFMIF Post-CDR Equipartitioned RFQ designs. Design strategies are illustrated for combining several desirable characteristics, prioritized as minimum beam loss at energies above ~ 1 MeV, low rf power, low peak field, short length, high percentage of accelerated particles. The CDR design has ~0.073% losses above 1 MeV, requires ~1.1 MW rf structure power, has KP factor 1.7,is 12.3 m long, and accelerates ~89.6% of the input beam. A new Post-CDR design has ~0.077% losses above 1 MeV, requires ~1.1 MW rf structure power, has KP factor 1.7 and ~8 m length, and accelerates ~97% of the input beam. A complete background for the designs is given, and comparisons are made. Beam-loss distributions are used as input for nuclear physics simulations of radioactivity effects in the IFMIF accelerator hall, to give information for shielding, radiation safety and maintenance design. Beam-loss distributions resulting from a ~1M particle input distribution representative of the IFMIF ECR ion source are presented. The simulations reported were performed with a consistent family of codes. Relevant comparison with other codes has not been possible as their source code is not available. Certain differences have been noted but are not consistent over a broad range of designs and parameter range. The exact transmission found by any of these codes should be treated as indicative, as each has various sensitivities in

  7. Coaxial volumetric velocimetry

    Science.gov (United States)

    Schneiders, Jan F. G.; Scarano, Fulvio; Jux, Constantin; Sciacchitano, Andrea

    2018-06-01

    This study describes the working principles of the coaxial volumetric velocimeter (CVV) for wind tunnel measurements. The measurement system is derived from the concept of tomographic PIV in combination with recent developments of Lagrangian particle tracking. The main characteristic of the CVV is its small tomographic aperture and the coaxial arrangement between the illumination and imaging directions. The system consists of a multi-camera arrangement subtending only few degrees solid angle and a long focal depth. Contrary to established PIV practice, laser illumination is provided along the same direction as that of the camera views, reducing the optical access requirements to a single viewing direction. The laser light is expanded to illuminate the full field of view of the cameras. Such illumination and imaging conditions along a deep measurement volume dictate the use of tracer particles with a large scattering area. In the present work, helium-filled soap bubbles are used. The fundamental principles of the CVV in terms of dynamic velocity and spatial range are discussed. Maximum particle image density is shown to limit tracer particle seeding concentration and instantaneous spatial resolution. Time-averaged flow fields can be obtained at high spatial resolution by ensemble averaging. The use of the CVV for time-averaged measurements is demonstrated in two wind tunnel experiments. After comparing the CVV measurements with the potential flow in front of a sphere, the near-surface flow around a complex wind tunnel model of a cyclist is measured. The measurements yield the volumetric time-averaged velocity and vorticity field. The measurements of the streamlines in proximity of the surface give an indication of the skin-friction lines pattern, which is of use in the interpretation of the surface flow topology.

  8. Fueling by coaxial plasma guns

    International Nuclear Information System (INIS)

    Marshall, J.

    1978-01-01

    The operating principles of pulsed coaxial guns are reviewed. Some problems involved with the injection of plasma beams from these guns into containment fields are described. The injection during reactor operating conditions is then discussed

  9. The cyclotron laboratory and the RFQ accelerator in Bern

    International Nuclear Information System (INIS)

    Braccini, S.; Ereditato, A.; Kreslo, I.; Nirkko, M.; Weber, M.; Scampoli, P.; Bremen, K. von

    2013-01-01

    Two proton accelerators have been recently put in operation in Bern: an 18 MeV cyclotron and a 2 MeV RFQ linac. The commercial IBA 18/18 cyclotron, equipped with a specifically conceived 6 m long external beam line ending in a separate bunker, will provide beams for routine 18-F and other PET radioisotope production as well as for novel detector, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. The accelerator is embedded into a complex building hosting two physics laboratories and four Good Manufacturing Practice (GMP) laboratories. This project is the result of a successful collaboration between the Inselspital, the University of Bern and private investors, aiming at the constitution of a combined medical and research centre able to provide the most cutting-edge technologies in medical imaging and cancer radiation therapy. The cyclotron is complemented by the RFQ with the primary goals of elemental analysis via Particle Induced Gamma Emission (PIGE), and the detection of potentially dangerous materials with high nitrogen content using the Gamma-Resonant Nuclear Absorption (GRNA) technique. In this context, beam instrumentation devices have been developed, in particular an innovative beam profile monitor based on doped silica fibres and a setup for emittance measurements using the pepper-pot technique. On this basis, the establishment of a proton therapy centre on the campus of the Inselspital is in the phase of advanced study

  10. Conceptual designs of beam choppers for RFQ linacs

    International Nuclear Information System (INIS)

    Nath, S.; Stevens, S.R. Jr.; Wangler, T.P.

    1995-01-01

    A design study at Los Alamos of a linac/accumulator ring facility for a pulsed neutron spallation source calls for an H - beam with a chopped structure of approximately 200-ns beam-free segments every 600-ns. The required angular impulse can easily be provided with existing pulse power technology and traveling wave structures with a transverse electric field similar to those now available. The deflected beam is then restored by suitable collimation. Chopping is relatively easily done at sufficiently low energies, where the beam is easily deflected, and beam powers are not too large. However, the energy should be high enough so that the space-charge blow-up of the beam can be controlled with adequate focusing. LAMPF presently uses a traveling-wave beam chopper at 750 keV, before injection into the drift tube linac (DTL). In the new linac designs, a radiofrequency quadrupole (RFQ) linac would typically bunch and accelerate the high intensity H - beam from 100 keV to 7 MeV. In this paper, the authors present concepts for beam-chopper systems both before and after the RFQ. The beam-optics designs are presented, together with numerical simulation results

  11. The cyclotron laboratory and the RFQ accelerator in Bern

    Energy Technology Data Exchange (ETDEWEB)

    Braccini, S.; Ereditato, A.; Kreslo, I.; Nirkko, M.; Weber, M. [Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics (LHEP), University of Bern, Sidlerstrasse 5, CH-3012 Bern (Switzerland); Scampoli, P. [Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics (LHEP), University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland and Department of Physical Sciences, University Federico II, Via Cintia, I-60126 Napoli (Italy); Bremen, K. von [SWAN Isotopen AG, Inselspital, CH-3010 Bern (Switzerland)

    2013-07-18

    Two proton accelerators have been recently put in operation in Bern: an 18 MeV cyclotron and a 2 MeV RFQ linac. The commercial IBA 18/18 cyclotron, equipped with a specifically conceived 6 m long external beam line ending in a separate bunker, will provide beams for routine 18-F and other PET radioisotope production as well as for novel detector, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. The accelerator is embedded into a complex building hosting two physics laboratories and four Good Manufacturing Practice (GMP) laboratories. This project is the result of a successful collaboration between the Inselspital, the University of Bern and private investors, aiming at the constitution of a combined medical and research centre able to provide the most cutting-edge technologies in medical imaging and cancer radiation therapy. The cyclotron is complemented by the RFQ with the primary goals of elemental analysis via Particle Induced Gamma Emission (PIGE), and the detection of potentially dangerous materials with high nitrogen content using the Gamma-Resonant Nuclear Absorption (GRNA) technique. In this context, beam instrumentation devices have been developed, in particular an innovative beam profile monitor based on doped silica fibres and a setup for emittance measurements using the pepper-pot technique. On this basis, the establishment of a proton therapy centre on the campus of the Inselspital is in the phase of advanced study.

  12. Design and performance of an RFQ cooler and buncher

    Energy Technology Data Exchange (ETDEWEB)

    Szerypo, J.; Ban, G.; Le Brun, C.; Delahaye, P.; Lienard, E.; Mauger, F.; Naviliat, O.; Tamain, B. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire; Hennecart, D. [Centre Interdisciplinaire de Recherche Ions Lasers, 14 - Caen (France)

    1999-10-01

    Several new experiments, planned or in preparation at low energy radioactive beam facilities, require the cooling and bunching of radioactive beams. This may be performed with a radiofrequency quadruple (RFQ) cooler and buncher, where the ions are cooled in a buffer gas while being guided by an oscillating RFQ field. This work describes the performance of such a device, which has been designed and studied in order to be extended for the cooling of light ions. The analysis requires extensive computer simulations, which are done with two approaches: the macroscopic and the microscopic. The latter approach is able to account for the RF-heating effect and the calculations were performed by the monte Carlo method. The cooling formalism was extendedto include a charge-exchange effect. The charge-exchange cross sections were calculated theoretically in a quantum-mechanical formalism for different ion-atom combinations. The simulations have shown in particular that for the cooling of {sup 6}He{sup +} ions, {sup 4}He is excluded as buffer gas because of the resonant charge exchange processes which drastically decreases the transmission. On the other hand, the cooling of {sup 6}He{sup +} ions with H{sub 2} as buffer gas appears as a promising solution. The most relevant cooler design parameters are proposed. A project of a complete system, including the deceleration, extraction and transfer sections, is presented. (authors)

  13. Search method optimization technique for thermal design of high power RFQ structure

    International Nuclear Information System (INIS)

    Sharma, N.K.; Joshi, S.C.

    2009-01-01

    RRCAT has taken up the development of 3 MeV RFQ structure for the low energy part of 100 MeV H - ion injector linac. RFQ is a precision machined resonating structure designed for high rf duty factor. RFQ structural stability during high rf power operation is an important design issue. The thermal analysis of RFQ has been performed using ANSYS finite element analysis software and optimization of various parameters is attempted using Search Method optimization technique. It is an effective optimization technique for the systems governed by a large number of independent variables. The method involves examining a number of combinations of values of independent variables and drawing conclusions from the magnitude of the objective function at these combinations. In these methods there is a continuous improvement in the objective function throughout the course of the search and hence these methods are very efficient. The method has been employed in optimization of various parameters (called independent variables) of RFQ like cooling water flow rate, cooling water inlet temperatures, cavity thickness etc. involved in RFQ thermal design. The temperature rise within RFQ structure is the objective function during the thermal design. Using ANSYS Programming Development Language (APDL), various multiple iterative programmes are written and the analysis are performed to minimize the objective function. The dependency of the objective function on various independent variables is established and the optimum values of the parameters are evaluated. The results of the analysis are presented in the paper. (author)

  14. Development of a 325 MHz ladder-RFQ of the 4-rod-type

    Energy Technology Data Exchange (ETDEWEB)

    Schuett, Maximilian; Ratzinger, Ulrich [Institut fuer Angewandte Physik, Goethe-Universitaet, Frankfurt a. M. (Germany); Brodhage, Robert [GSI, Darmstadt (Germany)

    2015-07-01

    For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. In the low energy section, between the Ion Source and the main linac an RFQ will be used. The 325 MHz RFQ will accelerate protons from 95 keV to 3.0 MeV. This particular high frequency for an RFQ creates difficulties, which are challenging in developing this cavity. In order to define a satisfactory geometrical configuration for this resonator, both from the RF and the mechanical point of view, different designs have been examined and compared. Very promising results have been reached with a ladder type RFQ, which has been investigated since 2013. We present recent 3D simulations of the general layout and of a complete cavity demonstrating the power of a ladder type RFQ as well as measurements of a 0.8 m prototype RFQ, which was manufactured in late 2014 and designed for RF power and vacuum tests. We outline a possible RF layout for the RFQ within the new FAIR proton injector and highlight the mechanical advantages.

  15. Coaxial test fixture

    Science.gov (United States)

    Praeg, Walter F.

    1986-01-01

    An assembly is provided for testing one or more contact material samples in a vacuum environment. The samples are positioned as an inner conductive cylinder assembly which is mounted for reciprocal vertical motion as well as deflection from a vertical axis. An outer conductive cylinder is coaxially positioned around the inner cylinder and test specimen to provide a vacuum enclosure therefor. A power source needed to drive test currents through the test specimens is connected to the bottom of each conductive cylinder, through two specially formed conductive plates. The plates are similar in form, having a plurality of equal resistance current paths connecting the power source to a central connecting ring. The connecting rings are secured to the bottom of the inner conductive assembly and the outer cylinder, respectively. A hydraulic actuator is also connected to the bottom of the inner conductor assembly to adjust the pressure applied to the test specimens during testing. The test assembly controls magnetic forces such that the current distribution through the test samples is symmetrical and that contact pressure is not reduced or otherwise disturbed.

  16. Linac4 RFQ assembly is carried out before installation in Building 152

    CERN Multimedia

    Anna Pantelia

    2012-01-01

    This series of pictures documents the assembly phase of the Linac4 RFQ (Radio Frequency Quadrupole), performed at the end of July 2012. The Linac4 RFQ is made of 3 modules, 1 meter each, assembled together to accelerate the H- or proton beam from the ion source extraction at 45 kV to the energy of 3 MeV. The RFQ is the first of the Linac4 accelerating structures, which will increase to 160 MeV the beam injection energy into the PS Booster as from the end of LS2.

  17. Results of L3 BGO calorimeter calibration using an RFQ accelerator

    CERN Document Server

    Chaturvedi, U K; Gataullin, M; Gratta, Giorgio; Kirkby, D; Lu, W; Newman, H; Shvorob, A V; Tully, C; Zhu, R

    2000-01-01

    A novel calibration system based on a radiofrequency-quadrupole (RFQ) accelerator has been installed in the L3 experiment. Radiative capture of 1.85 MeV protons from the RFQ accelerator in a lithium target produces a flux of 17.6 MeV photons which are used to calibrate 11000 crystals of the L3 BGO calorimeter. In this paper we present results of the RFQ run taken in November 1997. A calibration precision of 0.6% was reached in the barrel of the L3 BGO calorimeter, and 0.7% in the BGO endcaps. (8 refs).

  18. Comparison of beam simulations with measurements for a 1.25-MeV, CW RFQ

    International Nuclear Information System (INIS)

    Smith, H.V. Jr.; Bolme, G.O.; Sherman, J.D.; Stevens, R.R. Jr.; Young, L.M.; Zaugg, T.J.

    1998-01-01

    The Low-Energy Demonstration Accelerator (LEDA) injector is tested using the Chalk River Injector Test Stand (CRITS) radio-frequency quadrupole (RFQ) as a diagnostic instrument. Fifty-keV, dc proton beams are injected into the 1.25-MeV, CW RFQ and transported to a beamstop. Computer-simulation-code predictions of the expected beam performance are compared with the measured beam currents and beam profiles. Good agreement is obtained between the measurements and the simulations at the 75-mA design RFQ output current

  19. Preliminary Study on 50MHz Heavy Ion RFQ without Pre-Bunchers

    International Nuclear Information System (INIS)

    Cho, Yong Sub; Jang, Ji Ho; Kim, Han Sung; Kwon, Hyeok Jung

    2009-01-01

    We are studying a Radio Frequency Quadrupole (RFQ) as a lower energy part for a 200-MeV/u heavy ion linear accelerator of the International Business and Science Belt Project. The RFQ accelerates the 10- keV/u heavy ion beams from ion source (hydrogen molecules to uranium) and injects the 300-keV/u beam to the superconducting linac. Table I shows the basic parameters for the RFQ accelerator. In this study, we assumed that pre-bunchers to accelerate two charge state is not required

  20. Analytical solution for the electrical properties of a radio-frequency quadrupole (RFQ) with simple vanes

    International Nuclear Information System (INIS)

    Lancaster, H.

    1982-01-01

    Although the SUPERFISH program is used for calculating the design parameters of an RFQ structure with complex vanes, an analytical solution for electrical properties of an RFQ with simple vanes provides insight into the parametric behavior of these more complicated resonators. The fields in an inclined plane wave guide with proper boundary conditions match those in one quadrant of an RFQ. The principle of duality is used to exploit the solutions to a radial transmission line in solving the field equations. Calculated are the frequency equation, frequency sensitivity factors, electric field, magnetic field, stored energy (U), power dissipation, and quality factor

  1. On development of RFQ vanes from beam dynamics data

    International Nuclear Information System (INIS)

    Chatterjee, Avik; Padhi, Rakesh; Banerjee, M.K.; Naik, Vaishali; Sanyal, Dirtha; Choudhury, Siddhartha De; Chakrabarti, Alok

    2005-01-01

    Simulation at critical steps of product development greatly helps to detect the design flaws at the earlier stage and gives a digital platform to iterate the design and process at the initial stage. This helps to reduce the risk of failure considerably and gives an alternative to reduce the number of physical prototypes for design validation. Modern concepts of virtual prototyping for predicting functional behaviour of a product and process are gaining momentum globally as it is the fully integrated approach to converge the concepts of functional design, Design for Manufacturing (DFM), Design for Assembly (DFA) and manufacturing process simulation. This concept has been partially implemented in development of RFQ (Radio Frequency Quadruple) vanes and the basic guidelines have been discussed. (author)

  2. Design of the new couplers for C-ADS RFQ

    Science.gov (United States)

    Shi, Ai-Min; Sun, Lie-Peng; Zhang, Zhou-Li; Xu, Xian-Bo; Shi, Long-Bo; Li, Chen-Xing; Wang, Wen-Bin

    2015-04-01

    A new special coupler with a kind of bowl-shaped ceramic window for a proton linear accelerator named the Chinese Accelerator Driven System (C-ADS) at the Institute of Modern Physics (IMP) has been simulated and constructed and a continuous wave (CW) beam commissioning through a four-meter long radio frequency quadruple (RFQ) was completed by the end of July 2014. In the experiments of conditioning and beam, some problems were promoted gradually such as sparking and thermal issues. Finally, two new couplers were passed with almost 110 kW CW power and 120 kW pulsed mode, respectively. The 10 mA intensity beam experiments have now been completed, and the couplers during the operation had no thermal or electro-magnetic problems. The detailed design and results are presented in the paper. Supported by Strategic Priority Research Program of Chinese Academy of Sciences (XDA03020500)

  3. Beam tests of the 12 MHz RFQ RIB injector for ATLAS

    International Nuclear Information System (INIS)

    Clifft, B. E.; Kaye, R. A.; Kedzie, M.; Shepard, K. W.

    1999-01-01

    Beam tests of the ANL 12 MHz Radio-Frequency Quadruple (RFQ), designed for use as the initial element of an injector system for radioactive beams into the existing ATLAS accelerators, are in progress. Recent high-voltage tests of the RFQ without beam achieved the design intervane voltage of 100 kV CW, enabling beam tests with A/q as large as 132 using beams from the ANL Physics Division 4 MV Dynamitron accelerator facility. Although the RFQ was designed for bunched beams, initial tests have been performed with unbunched beams. Experiments with stable, unbunched beams of singly-charged 132 Xe and 84 Kr measured the output beam energy distribution as a function of the RFQ operating voltage. The observed energies are in excellent agreement with numerical beam simulations

  4. Operating experience of upgraded radio frequency source at 76 MHz coupled to heavy ion RFQ

    International Nuclear Information System (INIS)

    Pande, Manjiri; Shiju, A.; Patel, N.R.; Shrotriya, S.D.; Bhagwat, P.V.

    2015-01-01

    A heavy ion radio frequency quadrupole (RFQ) accelerator has been developed at BARC (BARC). A RF source which was designed and developed at 76 MHz earlier, has been upgraded and coupled to heavy ion RFQ successfully. The DC bias supplies of this source have been replaced with new supplies having high efficiency and well filteration against RF interference (RFI). The driver of main power amplifier has been replaced with indigenously designed and developed unit. The earlier introduced microcontroller based interlock experienced RF noise issues. So, this circuit has been modified with the new circuit. With these modifications, the performance of the RF source was improved. Additionally, a separate low power RF source of around 100 + Watt was designed, developed and integrated with RFQ for its RF conditioning. This paper describes the details of up gradation of technologies implemented and coupling experience of this RF source with heavy ion RFQ. (author)

  5. Design and fabrication of Radio Frequency Quadrupole (RFQ) Accelerator at IUAC, New Delhi

    International Nuclear Information System (INIS)

    Ahuja, R.; Kothari, A.; Safvan, C.P.; Kumar, Sugam; Ram Sankar, P.

    2013-01-01

    As part of the accelerator augmentation program at Inter-University Accelerator Centre (IUAC), a high current injector (HCI) is being developed to inject high currents of highly charged ions into the superconducting LINAC. The ion beams produced by the Electron Cyclotron Resonance (ECR) based PKDELIS ion source will be injected into a Radio Frequency Quadrupole Accelerator (RFQ). The RFQ focuses and accelerates the ion beam. For the development of the RFQ Accelerator, a prototype of nearly half length was successfully built at IUAC to test the RF, thermal and mechanical design. The prototype is designed for 30 kW power at 48.5 MHz. This paper presents the mechanical design, fabrication and assembly of the final 2.5 m long RFQ. (author)

  6. RF Measurements and Tuning of the 750 MHz HF-RFQ

    CERN Document Server

    Koubek, Benjamin; Timmins, Marc; CERN. Geneva. ATS Department

    2017-01-01

    In the frame of the program on medical applications CERN has built a compact 750 MHz RFQ to be used as an injector for a hadron therapy linac. This RFQ was designed to accelerate protons to an energy of 5 {\\lambda} MeV within only 2 m length. It is divided into four segments and equipped with 32 tuners in total. The length of the RFQ corresponds to 5 which is considered to be close to the limit for field adjustment using only piston tuners. Moreover the high frequency, which is about double the frequency of existing RFQs, results in a sensitive structure and requires careful tuning by means of the alignment of the pumping ports and fixed tuners. This report summarises the tuning procedure, RF and bead pull measurements of the RFQ.

  7. Beam tests of the 12 MHz RFQ RIB injector for ATLAS.

    Energy Technology Data Exchange (ETDEWEB)

    Clifft, B. E.; Kaye, R. A.; Kedzie, M.; Shepard, K. W.

    1999-05-06

    Beam tests of the ANL 12 MHz Radio-Frequency Quadruple (RFQ), designed for use as the initial element of an injector system for radioactive beams into the existing ATLAS accelerators, are in progress. Recent high-voltage tests of the RFQ without beam achieved the design intervane voltage of 100 kV CW, enabling beam tests with A/q as large as 132 using beams from the ANL Physics Division 4 MV Dynamitron accelerator facility. Although the RFQ was designed for bunched beams, initial tests have been performed with unbunched beams. Experiments with stable, unbunched beams of singly-charged {sup 132}Xe and {sup 84}Kr measured the output beam energy distribution as a function of the RFQ operating voltage. The observed energies are in excellent agreement with numerical beam simulations.

  8. Operating characteristics of a 2.0-MeV RFQ

    International Nuclear Information System (INIS)

    Purser, F.O.; Wadlinger, E.A.; Sander, O.R.; Potter, J.M.; Crandall, K.R.

    1983-01-01

    A second radio-frequency quadrupole (RFQ) accelerator has been designed, constructed and operated at Los Alamos National Laboratory. The accelerator's design parameters represent a major extension from the original Los Alamos RFQ, with the new accelerator being 2.5 times as long, having three times the output energy, and with 2.5 times the current limit. The new accelerator's operating characteristics were studied for 3 months before disassembly to incorporate design mofidications. Results are discussed

  9. The mechanical design and fabrication of a ridge-loaded waveguide for an RFQ

    International Nuclear Information System (INIS)

    Valdiviez, R.; Roybal, P.; Clark, B.; Martinez, F.; Casillas, D.; Gonzales, G.; Tafoya, J.

    1998-01-01

    A Radio Frequency Quadrupole (RFQ) accelerator with an RF power input of 2 MW and an H + beam output current of 100 mAmps at 6.7 MeV, continuous duty factor utilizes twelve nearly identical ridge-loaded waveguides. The ridge-loaded, vacuum waveguides couple the RF power to the RFQ accelerating cavity. The mechanical design and fabrication of the ridge-loaded waveguides are the topics of this paper

  10. Mechanical Design, Brazing and Assembly Procedures of the LINAC4 RFQ

    CERN Document Server

    Mathot, S; Briswalter, A; Callamand, Th; Carosone, J; Favre, N; Geisser, J M; Lombardi, A; Maire, V; Malabaila, M; Pugnat, D; Richerot, Ph; Riffaut, B; Rossi, C; Timmins, M; Vacca, A; Vandoni, G; Vretenar, M

    2010-01-01

    The Linac4 RFQ will accelerate the H- beam from the ion source to the energy of 3 MeV. The RFQ is composed of three sections of one meter each, assembled by means of ultra high vacuum flanges and adjustable centring rings. The complete 3-m long RFQ will be supported isostatically over 3 points like a simple beam in order to minimise the maximum deflection. The ridge line, used to feed the RF power into the RFQ, will be supported via springs and its position adjusted in such way that no strain is introduced into the RFQ at the moment of its connection. The mechanical design has been done at CERN where the modules are completely manufactured, heat treated and brazed also. In that way, all of the processes are carefully controlled and the influence, notably of the heat treatments, has been understood in a better way. Since 2002 several four vanes RFQ modules have been brazed at CERN for the TRASCO and IPHI projects. A two-step brazing procedure has been tested. This technique is actually used for the assembly of...

  11. Calculable resistors of coaxial design

    International Nuclear Information System (INIS)

    Kucera, J; Vollmer, E; Schurr, J; Bohacek, J

    2009-01-01

    1000 Ω and 1290.64 Ω coaxial resistors with calculable frequency dependence have been realized at PTB to be used in quantum Hall effect-based impedance measurements. In contradistinction to common designs of coaxial resistors, the design described in this paper makes it possible to remove the resistive element from the shield and to handle it without cutting the outer cylindrical shield of the resistor. Emphasis has been given to manufacturing technology and suppressing unwanted sources of frequency dependence. The adjustment accuracy is better than 10 µΩ Ω −1

  12. Fueling by coaxial plasma guns

    International Nuclear Information System (INIS)

    Marshall, J.

    1977-01-01

    A review of the operational characteristics of ''snowplow'' and ''deflagration'' coaxial plasma guns is given. The injection of these plasmas into containment fields is discussed. The effect of a background plasma on low-beta injection is mentioned. The use of high-beta injection for reactor plasmas is described

  13. Properties of coaxial magnetocumulative generators

    International Nuclear Information System (INIS)

    Kidder, R.E.

    1983-01-01

    The properties of a coaxial magnetocumulative generator (MCG) in which the current increases exponetially with time are derived and discussed. Such an exponential MCG possess highly desirable performance characteristics that are readily derived and expressed in terms of simple formulas. It is concluded that an exponential MCG may approach a capability of delivering 100 megajoules to a 1 nanohenry load in 1 microsecond

  14. A review of high beam current RFQ accelerators and funnels

    International Nuclear Information System (INIS)

    Schneider, J.D.

    1998-01-01

    The authors review the design features of several high-current (> 20-mA) and high-power (> 1-mA average) proton or H - injectors, RFQs, and funnels. They include a summary of observed performance and will mention a sampling of new designs, including the proposed incorporation of beam choppers. Different programs and organizations have chosen to build the RFQ in diverse configurations. Although the majority of RFQs are either low-current or very low duty-factor, several versions have included high-current and/or high-power designs for either protons or H - ions. The challenges of cooling, handling high space-charge forces, and coupling with injectors and subsequent accelerators are significant. In all instances, beam tests were a valuable learning experience, because not always did these as-built structures perform exactly as predicted by the earlier design codes. They summarize the key operational parameters, indicate what was achieved, and highlight what was learned in these tests. Based on this generally good performance and high promise, even more challenging designs are being considered for new applications that include even higher powers, beam funnels and choppers

  15. RFQ Reaction Cells for AMS: Developments and Applications

    Directory of Open Access Journals (Sweden)

    Kieser William E.

    2013-12-01

    Full Text Available The use of anion-gas interactions in Radiofrequency Quadrupole (RFQ ion guide reaction cells has been shown to be very effective in the elimination of a number of atomic and molecular isobars which have caused difficulties for Accelerator Mass Spectrometry (AMS measurements [1,2]. This presentation begins with a review of the early work leading to the use of ion-gas reactions and continues with a discussion the recent measurements of the efficacy of this technique, some of which involve fluoride molecular anions. However, the transformation of the equipment used for these proof-of-principle measurements into a system suitable for routine analysis has required attention to aspects of the ion beam transport and gas handling subsystems. For example, the cross sections of the ion-gas reactions, involving both the analyte ion as well as the isobar, are critically dependent on the ion energy which has to be reduced from the ion source energy, usually between 20 and 80 keV, to energies typically in the range of several eV, a task complicated by the energy spread and divergence of beams from AMS sputter sources. With simulations using SIMION 8.1 [3] and tests of promising configurations in a laboratory system, principles for the design of the retarder optics have been developed. These are discussed, along with their planned implementation in a next generation analytical system.

  16. A flight-qualified RFQ for the BEAR project

    International Nuclear Information System (INIS)

    Schrage, D.; Young, L.; Campbell, B.; Billen, J.H.; Wangler, T.; Stovall, J.; Martinez, F.; Clark, W.; Gibbs, S.; Bolme, G.; O'Shea, P.; Lynch, M.; Devenport, J.; Rathke, J.; Micich, R.; Rose, J.; Richter, R.; Rosato, G.

    1989-01-01

    A 1-MeV, 30-mA, low-duty factor, 425-MHz RFQ has been designed and constructed for the BEAR (Beam Experiments Aboard a Rocket) Project by Los Alamos National Laboratory, Grumman Space Systems Division, and GAR Electroformers. The design of this 1-m-long, lightweight (<55-kg) accelerator is unique in that it was constructed of four copper-plated aluminum quadrants joined longitudinally by a room-temperature electroforming process to produce a monolithic structure. There are no rf, vacuum, or mechanical joints in the vane/cavity region of the accelerator. As part of the design/fabrication process, spark-test, cold, and engineering model RFQs were constructed and tested. The completed flight unit has successfully passed static structural and thermal tests as well as dynamic structural (shake) tests according to the launch, separation, and flight specifications. In addition, the rf field distributions and beam-transport characteristics have been measured and found to satisfy the design requirements. 12 refs., 2 figs., 3 tabs

  17. Plasma rotation in coaxial discharges

    International Nuclear Information System (INIS)

    Masoud, M.M.; Soliman, H.M.; Elkhalafawy, T.A.

    1985-01-01

    Plasma rotation has been observed near the breech of the coaxial electrodes, which propagates inside the coaxial gun and moreover this has been detected in the expansion chamber. Azimuthal component of plasma current has been detected. The measuring of the axial magnetic field distribution in time along the expansion chamber-axis shows a single maximum peak for all position. Azimuthal component of electric field exists along the axis of the expansion chamber and results for two angular positions (0 0 , 180 0 ) at r 2.5 cm has been presented. Thus it is obvious that the whole plasma bulk moves in a screw configuration before and after the focus position. 9 fig

  18. Splitting Descartes

    DEFF Research Database (Denmark)

    Schilhab, Theresa

    2007-01-01

    Kognition og Pædagogik vol. 48:10-18. 2003 Short description : The cognitivistic paradigm and Descartes' view of embodied knowledge. Abstract: That the philosopher Descartes separated the mind from the body is hardly news: He did it so effectively that his name is forever tied to that division....... But what exactly is Descartes' point? How does the Kartesian split hold up to recent biologically based learning theories?...

  19. Coaxial fundus camera for opthalmology

    Science.gov (United States)

    de Matos, Luciana; Castro, Guilherme; Castro Neto, Jarbas C.

    2015-09-01

    A Fundus Camera for ophthalmology is a high definition device which needs to meet low light illumination of the human retina, high resolution in the retina and reflection free image1. Those constraints make its optical design very sophisticated, but the most difficult to comply with is the reflection free illumination and the final alignment due to the high number of non coaxial optical components in the system. Reflection of the illumination, both in the objective and at the cornea, mask image quality, and a poor alignment make the sophisticated optical design useless. In this work we developed a totally axial optical system for a non-midriatic Fundus Camera. The illumination is performed by a LED ring, coaxial with the optical system and composed of IR of visible LEDs. The illumination ring is projected by the objective lens in the cornea. The Objective, LED illuminator, CCD lens are coaxial making the final alignment easily to perform. The CCD + capture lens module is a CCTV camera with autofocus and Zoom built in, added to a 175 mm focal length doublet corrected for infinity, making the system easily operated and very compact.

  20. Development of 350 MHz/1000 Watt intermediate power amplifier for 400 keV RFQ accelerator

    International Nuclear Information System (INIS)

    Pande, M.M.; Patel, N.R.; Shinde, K.R.; Rao, M.K.V.; Handu, V.K.

    2005-01-01

    Two numbers of high power RF systems, each delivering around 35 to 40 kW of power at 350 MHz are being developed in BARC. These High Power Amplifiers (HPA) cater to the total need of 70 kW of RF power required by the 400 keV (Deuterium) RFQ accelerator. This RFQ will replace the existing 400 keV DC accelerator of 14 MeV Neutron Generator. The RFQ will accelerate a deuterium beam from 50 keV to 400 keV to impinge upon a tritium target inside a sub critical assembly. Each of these 35 / 40 KW HPA requires a drive power of around 1000 / 1500 Watt respectively. Hence a intermediate power amplifier (IPA) bas been designed to deliver the power of 1000 Watt at the rate of 350 MHz. The paper describes the development of this amplifier

  1. REX-ISOLDE RFQ Beam Dynamics Studies using CST EM Studio

    CERN Document Server

    Fraser, M A

    2014-01-01

    The original CNC milling files used to machine the electrodes of the REX-ISOLDE RFQ were acquired in late 2012 and electrostatic simulations were carried out using CST EM Studio in order to attain a 3D field map of the electric fields in the region around the beam axis. The objective was to construct a beam dynamics simulation tool that frees us from the constraints of the PARMTEQM code, which was used to design the RFQ, and that will afford us more flexibility in the studies needed for pre-bunching into the RFQ with an external multi-harmonic buncher. This note details the geometry of the electrodes and their simulation in CST EM Studio, the implementation of particle tracking in the computed field map using TRACK and benchmarking studies with PARMTEQM v3.09.

  2. Assembly and RF Tuning of the Linac4 RFQ at CERN

    CERN Document Server

    Rossi, C; Hansen, J; Lallement, JB; Lombardi, AM; Pugnat, D; Vandoni, G; Timmins, M; Vretenar, M; Mathot, S; Piquet, O; Novo, J; Le Noa, Y; France, A; Desmons, M

    2013-01-01

    The fabrication of Linac4 is progressing at CERN with the goal of making a 160 MeV H- beam available to the LHC injection chain as from 2015. In the Linac4 the first stage of beam acceleration, after its extraction from the ion source, is provided by a Radiofrequency Quadrupole accelerator (RFQ), operating at the RF frequency of 352.2 MHz and which accelerates the ion beam to the energy of 3 MeV. The RFQ, made of three modules, one meter each, is of the four-vane kind, has been designed in the frame of a collaboration between CERN and CEA and has been completely machined and assembled at CERN. The paper describes the assembly of the RFQ structure and reports the results of RF low power measurements, in order to achieve the required accelerating field flatness within 1% of the nominal field profile.

  3. Design of a 1 MeV 3He+ RFQ for the SAIC PET accelerator facility

    International Nuclear Information System (INIS)

    Cornelius, W.D.; Young, P.E.

    1993-01-01

    The novel design of a 1 MeV 3 He + radiofrequency quadrupole (RFQ) accelerator is discussed. This RFQ is the first segment of an accelerator for the production of radioisotopes for positron emission tomography (PET) applications. This RFQ is unusual in that two specific innovations were incorporated into the design. The mechanical design is a hybrid of conventional four-vane and four-rod geometries. This hybridization reduces the physical dimensions of the accelerator without sacrificing too much in rf efficiency and has the added benefit of reducing the sensitivity to mechanical alignment errors. In addition, the beam dynamics of the last few cells was modified to tailor the output beam parameters to improve the beam transport through the next accelerator section. The details of the mechanical structure, the mechanical and electrical alignment experiences, and a comparison of the theoretical and experimental performance of this accelerator are also discussed. (orig.)

  4. CFD simulation of coaxial injectors

    Science.gov (United States)

    Landrum, D. Brian

    1993-01-01

    The development of improved performance models for the Space Shuttle Main Engine (SSME) is an important, ongoing program at NASA MSFC. These models allow prediction of overall system performance, as well as analysis of run-time anomalies which might adversely affect engine performance or safety. Due to the complexity of the flow fields associated with the SSME, NASA has increasingly turned to Computational Fluid Dynamics (CFD) techniques as modeling tools. An important component of the SSME system is the fuel preburner, which consists of a cylindrical chamber with a plate containing 264 coaxial injector elements at one end. A fuel rich mixture of gaseous hydrogen and liquid oxygen is injected and combusted in the chamber. This process preheats the hydrogen fuel before it enters the main combustion chamber, powers the hydrogen turbo-pump, and provides a heat dump for nozzle cooling. Issues of interest include the temperature and pressure fields at the turbine inlet and the thermal compatibility between the preburner chamber and injector plate. Performance anomalies can occur due to incomplete combustion, blocked injector ports, etc. The performance model should include the capability to simulate the effects of these anomalies. The current approach to the numerical simulation of the SSME fuel preburner flow field is to use a global model based on the MSFC sponsored FNDS code. This code does not have the capabilities of modeling several aspects of the problem such as detailed modeling of the coaxial injectors. Therefore, an effort has been initiated to develop a detailed simulation of the preburner coaxial injectors and provide gas phase boundary conditions just downstream of the injector face as input to the FDNS code. This simulation should include three-dimensional geometric effects such as proximity of injectors to baffles and chamber walls and interaction between injectors. This report describes an investigation into the numerical simulation of GH2/LOX coaxial

  5. Software development for the RF measurement and analysis of RFQ accelerator

    International Nuclear Information System (INIS)

    Fu Shinian

    2002-01-01

    In a high current RFQ accelerator, it is required to tightly control the beam losses and beam emittance growth. For this reason, it is demanded to accurately measure and to correctly analyze field distribution and mode components, and eventually, to tune the RF field to reach its design values. LebView is a widely used software platform for the automatic measurement and data processing. The author will present the code development on this platform for the RFQ measurement and analysis, including some applications of the codes

  6. Software development for the RF measurement and analysis of RFQ accelerator

    CERN Document Server

    Fu Shin Ian

    2002-01-01

    In a high current RFQ accelerator, it is required to tightly control the beam losses and beam emittance growth. For this reason, it is demanded to accurately measure and to correctly analyze field distribution and mode components, and eventually, to tune the RF field to reach its design values. LebView is a widely used software platform for the automatic measurement and data processing. The will present the code development on this platform for the RFQ measurement and analysis, including some applications of the codes

  7. Software development for the RF measurement and analysis of RFQ accelerator

    International Nuclear Information System (INIS)

    Fu Shinian

    2002-01-01

    In a high current RFQ accelerator, it is required to tightly control the beam losses and beam emittance growth. For this reason, it is demanded to accurately measure and to correctly analyze field distribution and mode components, and eventually, to tune the RF field to reach its design values. LebView is a widely used software platform for the automatic measurement and data processing, the authors present authors' code development on this platform for the RFQ measurement and analysis, including some applications of the codes

  8. C-w operation of a 2-MeV RFQ accelerator

    International Nuclear Information System (INIS)

    Cornelius, W.D.

    1986-01-01

    We have achieved reliable cw operation of the Fusion Materials Irradiation Test (FMIT) radio-frequency quadrupole (RFQ) accelerator and have accelerated 40 mA of H 2 + beam to an energy of 2 MeV. The technical considerations for future cw accelerator designs, based on our experience in achieving cw operation, will be presented. Also to be discussed are measurements of beam emittance, matching into the RFQ, and beam transmission through the accelerator. These measurements will be compared with results of theoretical simulations of the device. The diagnostics instrumentation developed for characterizing intense cw beams also will be discussed, as well as the performance of those devices

  9. Expériences sur les RFQ TRASCO et IPHI et développement du RFQ pour le Linac4

    CERN Document Server

    Mathot, S

    2008-01-01

    Depuis 1999, le CERN est impliqué dans le brasage sous vide des RFQ TRASCO et de IPHI depuis 2002. Pour ces deux projets, les tronçons RFQ sont constitués de 4 pôles indépendants usinés dans du cuivre OFE forgé. Ces pôles ont une longueur comprise entre 1000 et 1200 mm et doivent être assemblés avec une précision de l?ordre de 20 microns. La masse totale d?un tronçon est comprise entre 300 et 450 Kg. La procédure de brasage qui a été proposée et utilisée pour 5 tronçons jusqu'à présent consiste en deux étapes distinctes, l?une horizontale et l?autre verticale. Ce papier décrit ces étapes et les solutions utilisées pour l?alignement des pôles avant brasage. Les problèmes rencontrés, notamment en raison de la relaxation de contraintes lors du cycle thermique de brasage sont discutés. Enfin, les choix techniques retenus pour la fabrication des RFQ pour le projet Linac4 sont présentés.

  10. Development of a new RFQ beam cooler and buncher for the CANREB project at TRIUMF

    Energy Technology Data Exchange (ETDEWEB)

    Barquest, B.R. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); Bale, J.C.; Dilling, J. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); UBC Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Gwinner, G. [University of Manitoba, Department of Physics and Astronomy, Allen Building, Winnipeg, MB R3T 2N2 (Canada); Kanungo, R. [Saint Mary’s University, Astronomy and Physics Department, 923 Robie Street, Halifax, NS B3H 3C3 (Canada); Krücken, R. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada); UBC Department of Physics and Astronomy, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Pearson, M.R. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3 (Canada)

    2016-06-01

    A new radiofrequency quadrupole (RFQ) based ion beam cooler and buncher is under development for the CANadian Rare-isotope facility with Electron Beam ion source (CANREB) project at TRIUMF. The CANREB project requires an RFQ buncher that will efficiently accept continuous beams of rare isotopes from either the Advanced Rare IsotopE Laboratory (ARIEL) or Isotope Separator and ACcelerator (ISAC) target by way of a high resolution magnetic spectrometer, with energies up to 60 keV and deliver bunched beams to an electron beam ion source (EBIS) for charge breeding. The energy of the bunched beam delivered to the EBIS will be adjustable to match the requirements of the existing post acceleration infrastructure. The CANREB RFQ incorporates design considerations to facilitate ease of use over a wide range of ion masses, and is intended to accommodate incident beam rates as high as 10{sup 8} pps, delivering beam bunches at 100 Hz. An overview of the CANREB RFQ design concept will be presented, informed by results from both ion optical simulations as well as commissioning efforts with other beam cooler and buncher devices. Simulation results indicate that the design is well suited to deliver high quality bunched beams with high efficiency with as many as 10{sup 6} ions per bunch.

  11. Progress in the fabrication of the RFQ accelerator for the CERN Linac4

    CERN Document Server

    Rossi, C; Lallement, J B; Lombardi, A M; Mathot, S; Pugnat, D; Timmins, M; Vandoni, G; Vretenar, M; Desmons, M; France, A; Le Noa, Y; Novo, G; Piquet, O

    2010-01-01

    The construction of Linac4, the new 160 MeV CERN H- injector, has started with the goal of improving the LHC injection chain from 2015 with a new higher energy linac. The low energy front end of Linac4 is based on a 352 MHz, 3-m long Radiofrequency Quadrupole (RFQ) accelerator [1]. The RFQ accelerates the 70 mA, 45 keV H- beam from the RF source to the energy of 3 MeV. The fabrication of the RFQ has started at CERN in 2009 and is presently in progress, aiming at the completion of the full structure by early 2011. The RFQ consists of three modules, one meter each; the fabrication alternates machining phases and stress relief cycles, for copper stabilization. Two brazing steps are required: one to assemble the four parts composing a module, and a second one to install the stainless steel flanges. In order to monitor that the tight mechanical and alignment budget is not exceeded, metrology measurements at the CERN workshop and RF bead-pull measurements are performed during the fabrication process. In this paper ...

  12. Development of RF non-IQ sampling module for Helium RFQ LLRF system

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hae-Seong; Ahn, Tae-Sung; Kim, Seong-Gu; Kwon, Hyeok-Jung; Kim, Han-Sung; Song, Young-Gi; Seol, Kyung-Tae; Cho, Yong-Sub [KOMAC, Gyeongju (Korea, Republic of)

    2015-05-15

    KOMAC (Korea Multi-purpose Accelerator Complex) has a plan to develop the helium irradiation system. This system includes the Ion source, LEBT, RFQ, MEBT systems to transport helium particles to the target. Especially, the RFQ (Radio Frequency Quadrupole) system should receive the 200MHz RF within 1% amplitude error stability. For supplying stable 200MHz RF to the RFQ, the low-level radio frequency (LLRF) should be controlled by control system. The helium RFQ LLRF control system adopted non- IQ sampling method to sample the analog input RF. Sampled input data will be calculated to get the I, Q values. These I, Q values will be used to monitor the amplitude and phase of the RF signal. In this paper, non-IQ sampling logic and amplitude and phase calculating logic of the FPGA will be introduced. Using Xilinx ISE design suite which is tool for developing the FPGA logic module, non-IQ sampling module and amplitude and phase computing module developed. In the future, PI gain module and frequency error computing module will be developed.

  13. Simulation of the Direct Digital Synthesis module for Helium RFQ LLRF system

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hae-Seong; Ahn, Tae-Sung; Kim, Seong-Gu; Kwon, Hyeok-Jung; Kim, Han-Sung; Song, Young-Gi; Seol, Kyung-Tae; Cho, Yong-Sub [Korea Atomic Energy Research Institute, Gyeongju (Korea, Republic of)

    2015-10-15

    In this paper, the DDS module in the FPGA simulated and the analysis result will be introduced. Using Xilinx ISE design suite which is tool for developing the FPGA logic module, DDS module simulated. KOMAC (Korea Multi-purpose Accelerator Complex) has a plan to develop the helium irradiation system. This system includes the Ion source, LEBT, RFQ, MEBT systems to transport helium particles to the target. Especially, the RFQ (Radio Frequency Quadrupole) system should receive the 200 MHz RF within 1% amplitude error stability. For supplying stable 200 MHz RF to the RFQ, the LLRF (low-level radio frequency) should be controlled by control system. This helium RFQ LLRF control system have a concept to track the cavity resonance frequency. For tracking the cavity resonance frequency, the FPGA (Field Programmable Gate Array) in the digital board will tune the frequency of the output sinusoidal signal. In order to implement this frequency tracking concept, the DDS (Direct Digital Synthesis) module should be implemented in the FPGA. In the future, frequency tracking system will be tested using test cavity.

  14. Downhole transmission system comprising a coaxial capacitor

    Science.gov (United States)

    Hall, David R [Provo, UT; Pixton, David S [Lehi, UT; Johnson, Monte L [Orem, UT; Bartholomew, David B [Springville, UT; Hall, Jr., H. Tracy; Rawle, Michael [Springville, UT

    2011-05-24

    A transmission system in a downhole component comprises a plurality of data transmission elements. A coaxial cable having an inner conductor and an outer conductor is disposed within a passage in the downhole component such that at least one capacitor is disposed in the passage and having a first terminal coupled to the inner conductor and a second terminal coupled to the outer conductor. Preferably the transmission element comprises an electrically conducting coil. Preferably, within the passage a connector is adapted to electrically connect the inner conductor of the coaxial cable and the lead wire. The coaxial capacitor may be disposed between and in electrically communication with the connector and the passage. In another embodiment a connector is adapted to electrical connect a first and a second portion of the inner conductor of the coaxial cable and a coaxial capacitor is in electrical communication with the connector and the passage.

  15. Realistic simulations of coaxial atomisation

    Science.gov (United States)

    Zaleski, Stephane; Fuster, Daniel; Arrufat Jackson, Tomas; Ling, Yue; Cenni, Matteo; Scardovelli, Ruben; Tryggvason, Gretar

    2015-11-01

    We discuss advances in the methodology for Direct Numerical Simulations of coaxial atomization in typical experimental conditions. Such conditions are extremely demanding for the numerical methods. The key difficulty seems to be the combination of high density ratios, surface tension, and large Reynolds numbers. We explore how using a momentum-conserving Volume-Of-Fluid scheme allows to improve the stability and accuracy of the simulations. We show computational evidence that the use of momentum conserving methods allows to reduce the required number of grid points by an order of magnitude in the simple case of a falling rain drop. We then apply these ideas to coaxial atomization. We show that in moderate-size simulations in air-water conditions close to real experiments, instabilities are still present and then discuss ways to fix them. Among those, removing small VOF debris and improving the time-stepping scheme are two important directions.The accuracy of the simulations is then discussed in comparison with experimental results and in particular the angle of ejection of the structures. The code used for this research is free and distributed at http://parissimulator.sf.net.

  16. Plasma focusing in coaxial gun

    International Nuclear Information System (INIS)

    Soliman, H.M.; Masoud, M.M.; El-Khalafawy, T.

    1986-01-01

    A capacitor bank has been discharged between two coaxial electrodes of 6.6 cm outer diameter, 3.2 cm inner diameter and length of 31.5 cm. filled with hydrogen gas at pressure of 310 μHg. Results show that, the axial and radial plasma current reach a maximum value at a position adjacent to the gun muzzle, at which the plasma focus occurs. The measurement of the electron temperature and density and azimuthal electric field along the axis of the expansion chamber, gives a maximum value at z∼18 cm from the gun muzzle, while the axial plasma current and velocity has a minimum value at that position. These results indicate that a second point of a plasma focus has been formed at z∼18 cm from the gun muzzle, along the axis of the expansion chamber

  17. Plasma sheath axial phase dynamics in coaxial device

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, H.M. (Plasma Physics Dept., NRC, Atomic Energy Authority, Cairo (Egypt)); Masoud, M.M. (Plasma Physics Dept., NRC, Atomic Energy Authority, Cairo (Egypt))

    1994-10-01

    The study of the plasma sheath dynamics in the axial phase has been carried out in a 3 kJ coaxial system of Mather type for two different inner electrode (IE) lengths, 20 cm and 31.5 cm. For both lengths, measurements showed that the plasma sheath is splitted into two layers at the breech, which is referred to as a shock front and its magnetic piston. It has been found that the two layers of the plasma current sheath rotate around the inner electrode. At the muzzle the back layer reverse its rotation direction due to the magnetic field structure of the system. Results showed that the axial velocity of the first layer is greater than the second one all over the axial phase within the range between 1.4 and 1.7. (orig.).

  18. Plasma sheath axial phase dynamics in coaxial device

    International Nuclear Information System (INIS)

    Soliman, H.M.; Masoud, M.M.

    1994-01-01

    The study of the plasma sheath dynamics in the axial phase has been carried out in a 3 kJ coaxial system of Mather type for two different inner electrode (IE) lengths, 20 cm and 31.5 cm. For both lengths, measurements showed that the plasma sheath is splitted into two layers at the breech, which is referred to as a shock front and its magnetic piston. It has been found that the two layers of the plasma current sheath rotate around the inner electrode. At the muzzle the back layer reverse its rotation direction due to the magnetic field structure of the system. Results showed that the axial velocity of the first layer is greater than the second one all over the axial phase within the range between 1.4 and 1.7. (orig.)

  19. Production quality controls and geometric characterization of the IFMIF-RFQ modules via the usage of a Coordinate Measuring Machine

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, Luigi, E-mail: luigi.ferrari@lnl.infn.it [INFN-LNL Laboratori Nazionali di Legnaro, Legnaro (Italy); Palmieri, Antonio [INFN-LNL Laboratori Nazionali di Legnaro, Legnaro (Italy); Pepato, Adriano; Prevedello, Alessandro; Dima, Razvan; Udup, Emil [INFN-Sezione di Padova, Padova (Italy)

    2017-02-15

    Highlights: • The production phases of the IFMIF-RFQ Modules is introduced. • Metrological controls through production are described and some results reported. • Radio-Frequency test is introduced by using geometric considerations. • Results from metrology and RF test are compared. • Acceptance of the modules has been guaranteed from that comparison. - Abstract: The RFQ of the IFMIF/EVEDA project (Pérez et al., 2015) is a 9.8 m long cavity able to accelerate a 125 mA deuteron beam from the input energy of 50 keV/u to the output energy of 2.5 MeV/u. Such RFQ operates at the frequency of 175 MHz and is composed of 18 mechanical modules approximately 0.55 long each (Pepato et al., 2010) . The RFQ realization involves the I.N.F.N. Sections of Padova, Torino and Bologna, as well as the Legnaro National Laboratories (L.N.L.). The metrological measurements via CMM (Coordinate Measuring Machine) provided to be a very effective tool both for quality controls along the RFQ production phases and in the reconstruction of the cavity geometric profile for each RFQ module. The scans in the most sensitive regions with respect to RF frequency, such as modulation, tips, base-vane width and vessel height provided the values of the cavity deviations from nominal geometry to be compared with design physic-driven tolerances and with RF measurements. Moreover, the comparison between mechanical and RF measurements suggests a methodology for the geometric reconstruction of the cavity axis and determines the final machining of the end surfaces of each module in view of the coupling with the adjacent ones. In this paper a detailed description of the metrological procedures and tests and of the RFQ along its production and assembly phases will be given and it will be shown that the adopted procedure allowed the attainment of the tuning range specifications for each RFQ module.

  20. Arc Plasma Gun With Coaxial Powder Feed

    Science.gov (United States)

    Zaplatynsky, Isidor

    1988-01-01

    Redesigned plasma gun provides improved metallic and ceramic coatings. Particles injected directly through coaxial bore in cathode into central region of plasma jet. Introduced into hotter and faster region of plasma jet.

  1. Armature design for coaxial induction launchers

    International Nuclear Information System (INIS)

    Andrews, J.A.; Devine, J.R.

    1991-01-01

    This paper reports on the armature design for a coaxial induction launcher that is influenced by a large set of highly coupled parameters. The simplifying assumptions often employed in coaxial accelerator analysis, such as a uniform or sinusoidal axial distribution of the azimuthal armature current, are unrealistic in induction launchers with monolithic single-turn armatures. In order to better understand the true dynamic behavior of coaxial accelerators, the Center for Electromechanics at The University of Texas at Austin (CEM-UT) has developed series of computer codes based on the current filament method. By utilizing these performance codes in conjunction with electromagnetic (EM) and mechanical finite element programs, it is now possible to design high performance induction launchers with armatures that can withstand the considerable mechanical and thermal loads inherent in a coaxial accelerator launch

  2. High temperature co-axial winding transformers

    Science.gov (United States)

    Divan, Deepakraj M.; Novotny, Donald W.

    1993-01-01

    The analysis and design of co-axial winding transformers is presented. The design equations are derived and the different design approaches are discussed. One of the most important features of co-axial winding transformers is the fact that the leakage inductance is well controlled and can be made low. This is not the case in conventional winding transformers. In addition, the power density of co-axial winding transformers is higher than conventional ones. Hence, using co-axial winding transformers in a certain converter topology improves the power density of the converter. The design methodology used in meeting the proposed specifications of the co-axial winding transformer specifications are presented and discussed. The final transformer design was constructed in the lab. Co-axial winding transformers proved to be a good choice for high power density and high frequency applications. They have a more predictable performance compared with conventional transformers. In addition, the leakage inductance of the transformer can be controlled easily to suit a specific application. For space applications, one major concern is the extraction of heat from power apparatus to prevent excessive heating and hence damaging of these units. Because of the vacuum environment, the only way to extract heat is by using a cold plate. One advantage of co-axial winding transformers is that the surface area available to extract heat from is very large compared to conventional transformers. This stems from the unique structure of the co-axial transformer where the whole core surface area is exposed and can be utilized for cooling effectively. This is a crucial issue here since most of the losses are core losses.

  3. Design of an upgradeable 45-100 mA RFQ accelerator for FAIR

    Science.gov (United States)

    Zhang, Chuan; Schempp, Alwin

    2009-10-01

    A 325 MHz, 35 mA, 3 MeV Radio-Frequency Quadrupole (RFQ) accelerator will be operated as the first accelerating structure of the proton linac injector for the newly planned international science center Facility for Antiproton and Ion Research (FAIR) at GSI, Germany. In previous design studies, two high beam intensities, 70 and 100 mA, were used. Most recently, the design intensity has been changed to 45 mA, which is closer to the operational value. Taking advantage of the so-called New Four-Section Procedure, a new design, which is upgradable from 45 to 100 mA, has been developed for the FAIR proton RFQ. Besides the upgradability analyses, robustness studies of the new design to spatial displacements of the input beam and field errors are presented as well.

  4. Development of 400- to 450-MHz RFQ resonator-cavity mechanical designs

    International Nuclear Information System (INIS)

    Hansborough, L.D.

    1982-01-01

    In the development of the radio-frequency quadrupole (RFQ) linac, the resonator cavity's mechanical design may be a challenge similar in magnitude to that of the development of the accelerator structure itself. Experience with the all-copper 425-MHz RFQ proof-of-principle linac has demonstrated that the resonator cavity must be structurally stiff and easily tunable. This experience has led to development of copper-plated steel structures having vanes that may be moved within a cylinder for tuning. Design of a flexible vane-to-cylinder radio-frequency (rf) joint, the vane, and the cylinder has many constraints dictated by the small-diameter cavities in the 400-MHz-frequency region. Two types of flexible, mechanical vane-to-cylinder rf joints are being developed at Los Alamos: the C-seal and the rf clamp-joint

  5. The Frankfurt ECRIS-RFQ facility for materials research with highly charged ions

    International Nuclear Information System (INIS)

    Stiebing, K.; Streitz, H.; Schmidt, L.; Schremmer, A.; Bethge, K.; Schmidt-Boecking, H.; Schempp, A.; Bessler, U.; Beller, P.; Madlung, J.

    1996-01-01

    The new accelerator for the production of highly charged heavy ions, presently installed at the Institut fuer Kernphysik consists of a 14 GHz ECR source in combination with an variable-energy RFQ post-accelerator. It is designed to deliver highly charged ions in the energy range between 1 keV/u (the ECRIS beam) and 100-200 keV/u with the (variable-energy radio frequency quadrupole) VE-RFQ. Investigations of transient processes with ns time constants will be possible by a single bunch system. Another attractive feature for materials research is the combination with ion beams from the 7 MV Van de Graaff. The status of the project and first results of beam measurements will be pre sented. (orig.)

  6. A 3He++ RFQ accelerator for the production of PET isotopes

    International Nuclear Information System (INIS)

    Pasquinelli, R.J.

    1997-05-01

    Project status of the 3He ++ 10.5 MeV RFQ Linear Accelerator for the production of PET isotopes will be presented. The accelerator design was begun in September of 1995 with a goal of completion and delivery of the accelerator to BRF in Shreveport, Louisiana by the summer of 1997. The design effort and construction is concentrated in Lab G on the Fermilab campus. Some of the high lights include a 25 mA peak current 3He' ion source, four RFQ accelerating stages that are powered by surplus Fermilab linac RF stations, a gas jet charge doubler, and a novel 540 degree bending Medium Energy Beam Transport (MEBT). The machine is designed to operate at 360 Hz repetition rate with a 2.5% duty cycle. The average beam current is expected to be 150-300 micro amperes electrical, 75- 150 micro amperes particle current

  7. RF field measurement of a four-vane type RFQ with PISLs

    International Nuclear Information System (INIS)

    Ueno, A.; Yamajaki, Y.

    1992-01-01

    Field instability due to a dipole mode mixing is the most significant disadvantage of an original four-vane type radio-frequency quadrupole (RFQ) linac. In order to avoid any dipole mode mixing, several pairs of vane coupling rings (VCRs) have mainly been used so far. However the VCR has complicated shape and is difficult to fabricate, particularly in the RFQ linac operated with a high-duty factor. Thus, a new field-stabilization concept was proposed and was referred to as a π-mode stabilizing loop (PISL) in a previous paper. The results of rf characteristics measurements on a low-power model cavity with or without PISLs are presented in this paper. The measurements showed that the PISLs were capable of stabilizing the accelerating mode, reducing the ratio of a dipole mode mixing from 7% to less than 1.5% (Author) 4 figs., tab., 10 refs

  8. Design of an upgradeable 45-100 mA RFQ accelerator for FAIR

    International Nuclear Information System (INIS)

    Zhang Chuan; Schempp, Alwin

    2009-01-01

    A 325 MHz, 35 mA, 3 MeV Radio-Frequency Quadrupole (RFQ) accelerator will be operated as the first accelerating structure of the proton linac injector for the newly planned international science center Facility for Antiproton and Ion Research (FAIR) at GSI, Germany. In previous design studies, two high beam intensities, 70 and 100 mA, were used. Most recently, the design intensity has been changed to 45 mA, which is closer to the operational value. Taking advantage of the so-called New Four-Section Procedure, a new design, which is upgradable from 45 to 100 mA, has been developed for the FAIR proton RFQ. Besides the upgradability analyses, robustness studies of the new design to spatial displacements of the input beam and field errors are presented as well.

  9. Design of Range Adaptive Wireless Power Transfer System Using Non-coaxial Coils

    Science.gov (United States)

    Yang, Dongsheng; Won, Sokhui; Hong, Huan

    2017-05-01

    Wireless Power Transfer (WPT) is a remarkable technology because of its convenience and applicability in harsh environment. Particularly, Magnetic Coupling WPT (MC-WPT) is a proper method to midrange power transfer, but the frequency splitting at over-coupling range, which is related with transfer distance, is challenge of transmission efficiency. In order to overcome this phenomenon, recently the range adaptive WPT is proposed. In this paper, we aim to the type with a set of non-coaxial driving coils, so that this may remove the connection wires from PA (Power Amplifier) to driving coil. And, when the radius of driving coil is changed, on the different gaps between driving and TX coils, coupling coefficient between these is computed in both cases of coaxial and non-coaxial configurations. In addition, the designing steps for 4-coil WPT system using non-coaxial coils are described with the example. Finally, the reliability of this topology has been proved and simulated with PSPICE.

  10. RF and constructional issues in the RFQ for the CERN laser ion source

    International Nuclear Information System (INIS)

    Bourquin, P.; Pirkl, W.; Umstatter, H.-H.

    1996-01-01

    An expandable RFQ has been designed and built. Its length can be modified in steps to match the different phases of the Laser Ion Source (LIS) study. This paper describes the basic design approach, the field simulations using MAFIA, the establishment of a lumped-element equivalent circuit using PSPICE, model measurements, RF cold measurements and the strategy to trim longitudinal field flatness. Results of RF power tests are also given. (author)

  11. A 30 KW RF power amplifier for the RFQ accelerator (Paper No. CP 27)

    International Nuclear Information System (INIS)

    Luktuke, R.D.; Garud, A.N.; Murthy, P.N.K.; Sethi, R.C.

    1990-01-01

    A radio frequency quadrupole (RFQ) accelerator, to accelerate deuterons to an energy of 150 keV with beam current of 20 mA, has been designed and is under construction. This accelerator needs approximately 30 kW of RF power to generate the desired voltage of 55 kV on the electrodes, at a frequency of 45 MHz. The power amplifier is designed with four stages of RF amplification using vacuum tubes. The first two stages are built with the tubes 6146 and BEL 250 CX, to deliver about 100 watts power to the grid circuit of the pre driver. The pre driver (EIMAC 5 CX 1500 A) and the driver (BEL 4000 CX) give an output power of about 5kW, at the grid of the high power amplifier. All the four tubes operate in class A/AB mode. The high power amplifier has been designed and is being built around the BEL power tetrode tube CQK-50-2. The output from the high power amplifier is fed to the RFQ, via a matching network to tranform the plate impedance to 50 ohm loop impedeance at the RFQ. The paper presents the design aspects of the high power amplifier, matching network and the results obtained for the earlier stages. (author). 3 refs., 3 tabs., 2 figs

  12. Commissioning of the Linac4 RFQ at the 3 MeV test stand

    CERN Document Server

    Rossi, C; Bellodi, G; Broere, J; Brunner, O; Lombardi, A M; Balula, J M; Yanez, P M; Noirjean, J; Pasquino, C; Raich, U; Roncarolo, F; Vretenar, M; Desmons, M; France, A; Piquet, O

    2013-01-01

    Linac4, the future 160 MeV Hˉ injector to the CERN Proton Synchrotron Booster, is presently under construction at CERN as a first step of the planned upgrade of the LHC injectors. The low energy section of LINAC4, consisting of an ion source, a 352.2 MHz Radio Frequency Quadrupole (RFQ) and a chopper line is being commissioned in a dedicated test stand before installation in its final position in the tunnel. The RFQ is designed to accelerate a 45 keV, 70 mA, Hˉ beam to 3 MeV, with an efficiency of 95% while preserving the transverse emittance. The RFQ, a four-vane structure 3 m in length, has been designed in collaboration with CEA/IRFU and is has been fabricated at the CERN workshop. The precise fabrication has allowed achieving a field flatness of 1%. The completion of the accelerating structure in September 2012 was followed by a complete series of bead-pull measurements and by high-power conditioning to the nominal power of 0.39 MW corresponding to a voltage of 78 kV across the 3 meters. Measurements wi...

  13. Design and configuration of VME EPICS driver for He RFQ LLRF control system

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Tae-Sung; Jeong, Hae-Seong; Kim, Seong-Gu; Song, Young-Gi; Kim, Han-Sung; Seol, Kyung-Tae; Kwon, Hyeok-Jung; Cho, Yong-Sub [KOMAC, Gyeongju (Korea, Republic of)

    2015-05-15

    In Helium Radio-Frequency Quadrupole (He RFQ) development, the role of the high-power Radio-Frequency (RF) is very important because it is responsible for stable delivery and efficient acceleration of the beam. Since the amplitude control requirements of LLRF system are ±1 % (amplitude), we need a precise remote control system for this reason. This system is referred to as Low-Level RF (LLRF) control system. This paper describes the basic configuration tasks performed by hardware side and the software side to build the LLRF control system, and describes the future work of the He RFQ LLRF control system based on this paper. LLRF control system development at the He RFQ development stage is important. LLRF control system development requires the exact configuration of hardware and software. For each of the Layer configuration is completed on the software side and hardware modules: vxworks operating system installation, EPICS BASE compilation, module source code compiled, object file loading and execution on vxworks, EPICS IOC operation check, etc.

  14. Field distribution in a coaxial electrostatic wiggler

    Directory of Open Access Journals (Sweden)

    Shi-Chang Zhang

    2010-09-01

    Full Text Available The field distribution in a coaxial electrostatic wiggler corresponds to the special solution of a Laplace equation in a cylindrical coordinate system with a boundary value problem of sinusoidal ripples. This paper is devoted to the physical and mathematical treatment for an analytical solution of the field distribution in the coaxial electrostatic wiggler. The explicit expression of the solution indicates that the field distribution in the coaxial electrostatic wiggler varies according to a periodic function in the longitudinal direction, and is related to the first and second kinds of modified Bessel functions in the radial direction, respectively. Comparison shows excellent agreement between the analytical formula and the computer simulation technology (CST results. The physical application of the considered system and its analytical solution are discussed.

  15. Coaxial plasma thrusters for high specific impulse propulsion

    Science.gov (United States)

    Schoenberg, Kurt F.; Gerwin, Richard A.; Barnes, Cris W.; Henins, Ivars; Mayo, Robert; Moses, Ronald, Jr.; Scarberry, Richard; Wurden, Glen

    1991-01-01

    A fundamental basis for coaxial plasma thruster performance is presented and the steady-state, ideal MHD properties of a coaxial thruster using an annular magnetic nozzle are discussed. Formulas for power usage, thrust, mass flow rate, and specific impulse are acquired and employed to assess thruster performance. The performance estimates are compared with the observed properties of an unoptimized coaxial plasma gun. These comparisons support the hypothesis that ideal MHD has an important role in coaxial plasma thruster dynamics.

  16. Energy balance in a coaxial plasma diode

    International Nuclear Information System (INIS)

    Ivanov, A.A. Jr.

    1999-01-01

    The energy fluxes in a coaxial system with a propagating convective magnetic-field wave are considered in an electron MHD model with inertia-free electrons. In contrast to the previous results obtained by other authors, it is shown that, with allowance for a finite electron pressure after the passage of the wave front, the energy flux at the boundary between the generator and coaxial system is continuous. The balance of energy fluxes in the system is studied. The angular anode point is shown to play an important role in this balance

  17. A compact ESQ system for transport and focusing of H- beam from ion source to RFQ

    International Nuclear Information System (INIS)

    Guharay, S.K.; Allen, C.K.; Reiser, M.; Saadatmand, K.; Chang, C.R.

    1992-01-01

    A compact, 6-lens electrostatic quadrupole (ESQ) LEBT (low energy beam transport) system has been constructed at the University of Maryland to transport a 30 mA, 35 kV H - beam over a distance of about 30 cm. A short einzel lens section is included at the end of the ESQ LEBT to establish a good matching of the beam to the radio frequency quadrupole (RFQ) accelerator, and to meet the emittance requirements of the linac in the Super-conducting Super Collider. Computer code predictions on the beam dynamics through the LEBT with experimentally measured input beam data are discussed. (Author) 5 figs., 6 refs

  18. An RF driven H- source and a low energy beam injection system for RFQ operation

    International Nuclear Information System (INIS)

    Leung, K.N.; Bachman, D.A.; Chan, C.F.; McDonald, D.S.

    1992-01-01

    An RF driven H - source has been developed at LBL for use in the Superconducting Super Collider (SSC). To date, an H - current of ∼40 mA can be obtained from a 5.6-cm-diam aperture with the source operated at a pressure of about 12 m Torr and 50 kW of RF power. In order to match the accelerated H - beam into the SSC RFQ, a low-energy H - injection system has been designed. This injector produces an outgoing H - beam free of electron contamination, with small radius, large convergent angle and small projectional emittance

  19. The EBIS-RFQ couple: a fully matched heavy ion 3rd pre-injector for Saturne

    International Nuclear Information System (INIS)

    Olivier, M.; Faure, J.; Laclare, J.L.; Lefebvre, J.M.; Leleux, G.; Ropert, A.; Tkatchenko, A.; Tkatchenko, M.

    1983-01-01

    Since 1978, the 3 GeV Synchrotron Saturne is routinely operated with proton, deuteron, helium beams and, since 1981 with polarized protons and deuterons. Heavy ions are expected in the Summer of 1983 by using a new pre-injector presently under construction. As already proposed by R.W.Hamm, the marriage of an EBIS and an RFQ can be looked upon generally as a very good means of production of heavy ion beams at low energy because it combines high charges states, therefore low voltage on the terminal, and low velocity acceleration. After the RFQ, the beam is injected into Saturne through 20 MeV Alvarez linac

  20. Reconnection conditions for a coaxial plasma gun

    International Nuclear Information System (INIS)

    Berk, H.L.; Hammer, J.H.; Shearer, J.W.

    1982-01-01

    A fluid model for the flow conditions necessary to form a compact torus from the plasma ejected by a coaxial plasma gun is developed. This is done by finding the conditions for which the steady-flow equations break down. Results are found for two cases; variable external flux and variable outer-wall radius

  1. Resonant Frequency Control For the PIP-II Injector Test RFQ: Control Framework and Initial Results

    Energy Technology Data Exchange (ETDEWEB)

    Edelen, A. L. [Colorado State U.; Biedron, S. G.; Milton, S. V.; Bowring, D.; Chase, B. E.; Edelen, J. P.; Nicklaus, D.; Steimel, J.

    2016-12-16

    For the PIP-II Injector Test (PI-Test) at Fermilab, a four-vane radio frequency quadrupole (RFQ) is designed to accelerate a 30-keV, 1-mA to 10-mA, H- beam to 2.1 MeV under both pulsed and continuous wave (CW) RF operation. The available headroom of the RF amplifiers limits the maximum allowable detuning to 3 kHz, and the detuning is controlled entirely via thermal regulation. Fine control over the detuning, minimal manual intervention, and fast trip recovery is desired. In addition, having active control over both the walls and vanes provides a wider tuning range. For this, we intend to use model predictive control (MPC). To facilitate these objectives, we developed a dedicated control framework that handles higher-level system decisions as well as executes control calculations. It is written in Python in a modular fashion for easy adjustments, readability, and portability. Here we describe the framework and present the first control results for the PI-Test RFQ under pulsed and CW operation.

  2. Configuration and application of He RFQ LLRF control system based on EPICS

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Tae-Sung; Jeong, Hae-Seong; Kim, Seong-Gu; Song, Young-Gi; Kim, Han-Sung; Seol, Kyung-Tae; Kwon, Hyeok-Jung; Cho, Yong-Sub [Korea Multipurpose Accelerator Complex, Gyeongju (Korea, Republic of)

    2015-10-15

    In He RFQ device, the high-power Radio-Frequency (RF) is very important because it is responsible for the stable delivery and efficient acceleration of the beam. Since that, the control system of high-power Radio-Frequency must be developed and this system is called LLRF control system. The LLRF control system required exquisite amplitude value that has ±1 % error range. We need a precise remote control system for this reason. This paper represents the configuration of LLRF control system in terms of software layers based on EPICS. Also, this paper explains the application of LLRF control system to test environment (hardware) and represents test result and suggests future work. The LLRF control system at the He RFQ is very important. The configuration of LLRF control system is completed on the software side and hardware modules: vxworks operating system installation, EPICS BASE compilation, module source code compiled, object file loading and execution on vxworks, EPICS IOC operation check, etc. The application of LLRF control system to module is implemented well: ADC module, DAC module, EPICS IOC test.

  3. Mechanical Design and Analysis of a 200 MHz, Bolt-together RFQ forthe Accelerator Driven Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Virostek, Steve; Hoff, Matt; Li, Derun; Staples, John; Wells,Russell

    2007-06-20

    A high-yield neutron source to screen sea-land cargocontainers for shielded Special Nuclear Materials (SNM) has been designedat LBNL [1,2]. The Accelerator-Driven Neutron Source (ADNS) uses theD(d,n)3He reaction to create a forward directed neutron beam. Keycomponents are a high-current radio-frequency quadrupole (RFQ)accelerator and a high-power target capable of producing a neutron fluxof>107 n/(cm2 cdot s) at a distance of 2.5 m. The mechanical designand analysis of the four-module, bolt-together RFQ will be presentedhere. Operating at 200 MHz, the 5.1 m long RFQ will accelerate a 40 mAdeuteron beam to 6 MeV. At a 5 percent duty factor, the time-average d+beam current on target is 1.5 mA. Each of the 1.27 m long RFQ moduleswill consist of four solid OFHC copper vanes. A specially designed 3-DO-ring will provide vacuum sealing between both the vanes and themodules. RF connections are made with canted coil spring contacts. Aseries of 60 water-cooled pi-mode rods provides quadrupole modestabilization. A set of 80 evenly spaced fixed slug tuners is used forfinal frequency adjustment and local field perturbationcorrection.

  4. Mechanical Design and Analysis of a 200 MHz, Bolt-together RFQ for the Accelerator Driven Neutron Source

    International Nuclear Information System (INIS)

    Virostek, Steve; Hoff, Matt; Li, Derun; Staples, John; Wells, Russell

    2007-01-01

    A high-yield neutron source to screen sea-land cargo containers for shielded Special Nuclear Materials (SNM) has been designed at LBNL [1,2]. The Accelerator-Driven Neutron Source (ADNS) uses the D(d,n)3He reaction to create a forward directed neutron beam. Key components are a high-current radio-frequency quadrupole (RFQ) accelerator and a high-power target capable of producing a neutron flux of >107 n/(cm2 cdot s) at a distance of 2.5 m. The mechanical design and analysis of the four-module, bolt-together RFQ will be presented here. Operating at 200 MHz, the 5.1 m long RFQ will accelerate a 40 mA deuteron beam to 6 MeV. At a 5 percent duty factor, the time-average d+beam current on target is 1.5 mA. Each of the 1.27 m long RFQ modules will consist of four solid OFHC copper vanes. A specially designed 3-DO-ring will provide vacuum sealing between both the vanes and the modules. RF connections are made with canted coil spring contacts. A series of 60 water-cooled pi-mode rods provides quadrupole mode stabilization. A set of 80 evenly spaced fixed slug tuners is used for final frequency adjustment and local field perturbation correction

  5. Magnetic reconnection and precursor effect in coaxial discharge

    International Nuclear Information System (INIS)

    Masoud, M.M.; Soliman, H.M.; El-Khalafawy, T.A.

    1988-01-01

    A precursor pulse was observed ahead of the plasma sheath produced by a coaxial electrode discharge system. The velocity of the precursor pulse was 4x10 7 cmS -1 and the velocity of the plasma sheath was 6x10 6 cmS -1 . The precursor pulse was unaffected when an axial magnetic field of 6 K.G. was applied to the propagation chamber, while the plasma sheath velocity increased and downstream structure were changed. The precursor pulse was split, sometimes, into two or more peaks, had the same shape and structure of the original one. The rest gas was heated up to 20 e.V. when the precursor pulse was destructed. The precursor pulse propagation mechanism and parameters showed that it had a solitary wave structure and behaviour. A reversed magnetic field was detected, when the plasma sheath had diamagnetic properties, where magnetic reconnection took place. Magnetic reconnection was responsible for energy transfiguration and wave generation. This was due to acceleration mechanism of charged particles occurred by the induced electric field at the moment of magnetic reconnection. The detected induced electric field had a high field intensity and fast rise time pulse. Several instabilities were referred to magnetic reconnection and the precursor pulse observed was a result of such instabilities

  6. Coded Splitting Tree Protocols

    DEFF Research Database (Denmark)

    Sørensen, Jesper Hemming; Stefanovic, Cedomir; Popovski, Petar

    2013-01-01

    This paper presents a novel approach to multiple access control called coded splitting tree protocol. The approach builds on the known tree splitting protocols, code structure and successive interference cancellation (SIC). Several instances of the tree splitting protocol are initiated, each...... instance is terminated prematurely and subsequently iterated. The combined set of leaves from all the tree instances can then be viewed as a graph code, which is decodable using belief propagation. The main design problem is determining the order of splitting, which enables successful decoding as early...

  7. Flow morphing by coaxial type plasma actuator

    Science.gov (United States)

    Toyoizumi, S.; Aono, H.; Ishikawa, H.

    2017-04-01

    The purpose of study is to achieve the fluid drag reduction of a circular disk by Dielectric Barrier Discharge Plasma Actuator (DBD-PA). We here introduced “Flow Morphing” concept that flow around the body was changed by DBD-PA jet, such as the body shape morphing. Coaxial type DBD-PA injected axisymmetric jet, generating the vortex region on the pressure side of the circular disk. The vortex generated by axisymmetric plasma jet and flow around circular disk were visualized by tracer particles method. The fluid drag was measured by compression type load cell. In addition streamwise velocity was measured by an X-type hot wire probe. The extent of fluid drag reduction by coaxial type DBD-PA jet was influenced by the volume of vortex region and the diameter of plasma electrode.

  8. Concept of ceramics-free coaxial waveguide

    International Nuclear Information System (INIS)

    Arai, Hiroyuki

    1994-01-01

    A critical key point of the ITER IC antenna is ceramics support of an internal conductor of a coaxial antenna feeder close to the plasma, because dielectric loss tangent of ceramics enhanced due to neutron irradiation limits significantly the antenna injection power. This paper presents a ceramics-free waveguide to overcome this problem by a T-shaped ridged waveguide with arms for the mechanical support. This ridged waveguide has a low cutoff frequency for its small cross section, which has been proposed for the conceptual design study of Fusion Experimental Reactor (FER) IC system and the high frequency supplementary IC system for ITER. This paper presents the concept of ceramics-free coaxial waveguide consisting of the coaxial-line and the ridged waveguide. This paper also presents the cutoff frequency and the electric field distribution of the ridged waveguide calculated by a finite element method and an approximate method. The power handling capability more than 3 MW is evaluated by using the transmission-line theory and the optimized antenna impedance considering the ITER plasma parameters. We verify this transmission-line model by one-tenth scale models experimentally. (author)

  9. Coaxial antenna for lower hybrid heating

    International Nuclear Information System (INIS)

    Le Gardeur, R.J.

    1981-02-01

    A coaxial antenna for the heating of toroidal plasmas has been conceived and constructed. Being wholly metallic (stainless steel), the several coaxial ceramic passages assuring the transit of the H.F. energy into vacuum being situated far from the plasma, the use of such antennas can be envisaged in next generation machines where the environment is particularily severe. The coaxial design (having a lower internal impedance than a wave guide) reduces the electric fields present in the antenna-plasma interface, assuring, at the same time, a spatial uniformity of the fields making possible a substantial reduction in the transmitted power density. The main technological advantages (with respect to a wave guide grill structure) are: (a) simplification of the construction especially in multi-channel systems (b) quasi-elimination of the problems associated with the ceramic windows transmitting the H.F. energy (c) absence of a low frequency cut-off making possible to place launching structures in vertical chimneys where space is limited (d) an eventual reduction of certain phenomena inherent to this type of heating such as particle acceleration, space charge separation, pondemotive forces etc

  10. Development of RFQ particle dynamics simulation tools and validation with beam tests

    Energy Technology Data Exchange (ETDEWEB)

    Maus, Johannes M.

    2010-07-01

    Two different strategies of designing RFQs have been introduced. The analytic description of the electric fields inside the quadrupole channel has been derived and the two term simplification was shown as well as the limitation of these approaches. The main work of this thesis was the implementation and analysis of a multigrid Poisson solver to describe the potential and electric field of RFQs which are needed to simulate the particle dynamics accurately. The main two ingredients of a multigrid Poisson solver are the ability of a Gauss-Seidel iteration method to smooth the error of an approximation within a few iteration steps and the coarse grid principle. The smoothing corresponds to a damping of the high frequency components of the error. After the smoothing, the error term can well be approximated on a coarser grid in which the low frequency components of the error on the fine grid are converted to high frequency errors on the coarse grid which can be damped further with the same Gauss-Seidel method. After implementation, the multigrid Poisson solver was analyzed using two different type of test problems: with and without a charge density. As a charge density, a homogeneously charged ball and cylinder were used to represent the bunched and unbunched beam and placed inside a quadruple channel. The solver showed a good performance. Next, the performance of the solver to calculate the external potentials (and fields) of RFQs was analyzed. Closing the analysis of the external field, the transmission and fraction of accelerated particles of the set of 12 RFQs for the two different methods were shown. In the last chapter of this thesis some experimental work on the MAFF (Munich Accelerator for Fission Fragments) IH-RFQ is described. The MAFF RFQ was designed to accelerate very neutron-rich fission fragments for various experiments. The machine was assembled in Frankfurt and a beam test stand was built. As a part of this thesis the shunt impedance of the structure was

  11. Development of RFQ particle dynamics simulation tools and validation with beam tests

    International Nuclear Information System (INIS)

    Maus, Johannes M.

    2010-01-01

    Two different strategies of designing RFQs have been introduced. The analytic description of the electric fields inside the quadrupole channel has been derived and the two term simplification was shown as well as the limitation of these approaches. The main work of this thesis was the implementation and analysis of a multigrid Poisson solver to describe the potential and electric field of RFQs which are needed to simulate the particle dynamics accurately. The main two ingredients of a multigrid Poisson solver are the ability of a Gauss-Seidel iteration method to smooth the error of an approximation within a few iteration steps and the coarse grid principle. The smoothing corresponds to a damping of the high frequency components of the error. After the smoothing, the error term can well be approximated on a coarser grid in which the low frequency components of the error on the fine grid are converted to high frequency errors on the coarse grid which can be damped further with the same Gauss-Seidel method. After implementation, the multigrid Poisson solver was analyzed using two different type of test problems: with and without a charge density. As a charge density, a homogeneously charged ball and cylinder were used to represent the bunched and unbunched beam and placed inside a quadruple channel. The solver showed a good performance. Next, the performance of the solver to calculate the external potentials (and fields) of RFQs was analyzed. Closing the analysis of the external field, the transmission and fraction of accelerated particles of the set of 12 RFQs for the two different methods were shown. In the last chapter of this thesis some experimental work on the MAFF (Munich Accelerator for Fission Fragments) IH-RFQ is described. The MAFF RFQ was designed to accelerate very neutron-rich fission fragments for various experiments. The machine was assembled in Frankfurt and a beam test stand was built. As a part of this thesis the shunt impedance of the structure was

  12. RFQ beam cooler and buncher for collinear laser spectroscopy of rare isotopes

    Science.gov (United States)

    Barquest, B. R.; Bollen, G.; Mantica, P. F.; Minamisono, K.; Ringle, R.; Schwarz, S.; Sumithrarachchi, C. S.

    2017-09-01

    A radiofrequency quadrupole (RFQ) ion beam cooler and buncher has been developed to deliver bunched beams with low transverse emittance, energy spread, and time spread to the BECOLA collinear laser spectroscopy system at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The beam cooler and buncher contains new features which enhance performance, especially for high count rate beams, as well as simplifying construction, maintenance, and operation. The transverse emittance, energy spread, and time spread of the bunched beam, as well as buncher efficiency are reported, showcasing the capabilities of the BECOLA facility to perform collinear laser spectroscopy measurements with bunched rare isotope beams at NSCL and at the future Facility for Rare Isotope Beams (FRIB).

  13. A digital signal processor based rf control system for the TRIUMF ISAC RFQ prototype

    International Nuclear Information System (INIS)

    Fong, K.; Fang, S.; Laverty, M.

    1996-01-01

    A stand alone digital signal processor is used to control the RFQ prototype in the TRIUMF ISAC development program. The advantage of a digital control system over the traditional analogue system is that it offers the higher degree of flexibility necessary for a development system. For this application the system is designed to have the outward appearance of an analogue system, and uses dials, knobs, and switches as the operator interface. The digital signal processor is used as a feedback controller during CW rf operation, with the feedback gain parameters continually adjustable. It is also able to perform the same regulation during pulsed operation, with additional feedforward compensation for initial pulse on duration. Using a low cost analogue-to-digital converter with a sample rate of 100 kHz, a regulation bandwidth of 10 kHz is achieved. (author)

  14. Numerical simulation of simultaneous acceleration of positive and negative ions in an RFQ

    International Nuclear Information System (INIS)

    Oguri, Y.

    1994-01-01

    By means of a numerical method, beam dynamics was analyzed for an RFQ, where mixtures of positive and negative ions were injected into the quadrupole channel. In order to simulate simultaneous bunching of ions with opposite charges, motion of particles injected into the cavity during two RF periods were traced under consideration of 3D Coulomb forces between particles. Effects of neighbor bunches were also taken into account. In the radial matching section of the structure, beam divergence due to space charge force was completely suppressed by the charge neutralization. However, it has been found that the attractive forces between positive and negative ions prevent bunch formation in the bunching section, leading to longitudinal beam loss. Dependence of the beam transmission efficiency on the input beam intensity is reported. These results are compared with those obtained when injecting single ion species

  15. Computations of Torque-Balanced Coaxial Rotor Flows

    Science.gov (United States)

    Yoon, Seokkwan; Chan, William M.; Pulliam, Thomas H.

    2017-01-01

    Interactional aerodynamics has been studied for counter-rotating coaxial rotors in hover. The effects of torque balancing on the performance of coaxial-rotor systems have been investigated. The three-dimensional unsteady Navier-Stokes equations are solved on overset grids using high-order accurate schemes, dual-time stepping, and a hybrid turbulence model. Computational results for an experimental model are compared to available data. The results for a coaxial quadcopter vehicle with and without torque balancing are discussed. Understanding interactions in coaxial-rotor flows would help improve the design of next-generation autonomous drones.

  16. Market Structure and Stock Splits

    OpenAIRE

    David Michayluk; Paul Kofman

    2001-01-01

    Enhanced liquidity is one possible motivation for stock splits but empirical research frequently documents declines in liquidity following stock splits. Despite almost thirty years of inquiry, little is known about all the changes in a stock's trading activity following a stock split. We examine how liquidity measures change around more than 2,500 stock splits and find a pervasive decline in most measures. Large stock splits exhibit a more severe liquidity decline than small stock splits, esp...

  17. Quasistatic modelling of the coaxial slow source

    International Nuclear Information System (INIS)

    Hahn, K.D.; Pietrzyk, Z.A.; Vlases, G.C.

    1986-01-01

    A new 1-D Lagrangian MHD numerical code in flux coordinates has been developed for the Coaxial Slow Source (CSS) geometry. It utilizes the quasistatic approximation so that the plasma evolves as a succession of equilibria. The P=P (psi) equilibrium constraint, along with the assumption of infinitely fast axial temperature relaxation on closed field lines, is incorporated. An axially elongated, rectangular plasma is assumed. The axial length is adjusted by the global average condition, or assumed to be fixed. In this paper predictions obtained with the code, and a limited amount of comparison with experimental data are presented

  18. Concentric Split Flow Filter

    Science.gov (United States)

    Stapleton, Thomas J. (Inventor)

    2015-01-01

    A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

  19. Split Malcev algebras

    Indian Academy of Sciences (India)

    project of the Spanish Ministerio de Educación y Ciencia MTM2007-60333. References. [1] Calderón A J, On split Lie algebras with symmetric root systems, Proc. Indian. Acad. Sci (Math. Sci.) 118(2008) 351–356. [2] Calderón A J, On split Lie triple systems, Proc. Indian. Acad. Sci (Math. Sci.) 119(2009). 165–177.

  20. Stochastic split determinant algorithms

    International Nuclear Information System (INIS)

    Horvatha, Ivan

    2000-01-01

    I propose a large class of stochastic Markov processes associated with probability distributions analogous to that of lattice gauge theory with dynamical fermions. The construction incorporates the idea of approximate spectral split of the determinant through local loop action, and the idea of treating the infrared part of the split through explicit diagonalizations. I suggest that exact algorithms of practical relevance might be based on Markov processes so constructed

  1. Simple measuring rod method for the coaxiality of serial holes

    Science.gov (United States)

    Wang, Lei; Yang, Tongyu; Wang, Zhong; Ji, Yuchen; Liu, Changjie; Fu, Luhua

    2017-11-01

    Aiming at the rapid coaxiality measurement of serial hole part with a small diameter, a coaxiality measuring rod for each layer hole with a single LDS (laser displacement sensor) is proposed. This method does not require the rotation angle information of the rod, and the coaxiality of serial holes can be calculated from the measured values of LDSs after randomly rotating the measuring rod several times. With the mathematical model of the coaxiality measuring rod, each factor affecting the accuracy of coaxiality measurement is analyzed by simulation, and the installation accuracy requirements of the measuring rod and LDSs are presented. In the tolerance of a certain installation error of the measuring rod, the relative center of the hole is calculated by setting the over-determined nonlinear equations of the fitting circles of the multi-layer holes. In experiment, coaxiality measurement accuracy is realized by a 16 μm precision LDS, and the validity of the measurement method is verified. The manufacture and measurement requirements of the coaxiality measuring rod are low, by changing the position of LDSs in the measuring rod, the serial holes with different sizes and numbers can be measured. The rapid coaxiality measurement of parts can be easily implemented in industrial sites.

  2. Coaxial discharge plasma parameters and radiation emission

    International Nuclear Information System (INIS)

    Solimen, H.M.

    1993-01-01

    Results are reported for experiments carried out on a Mather type coaxial discharge plasma device. Experimental measurements of the electron temperature and density for the plasma propagated from the coaxial discharge are determined by using a biased double electric probe. The experimental results illustrated that , there are two groups of the plasma in the ejected plasma bulk, at 9 cm from the muzzle axis, the plasma reached the probe at 20 μsec from the start of discharge. The first group has electron temperature and density 27 eV and 3 x 10 14 cm -3 respectively,while The second group has 25 eV and 3 x 10 14 cm -3 respectively. The decay rate of the electron temperature and density of each group is presented. The plasma radiation spectrum is detected by a dielectric filter at 3500 A degree or 6100 A degree . The experimental measurements showed that, without or with dielectric filters, the visible radiation consists from two pulses with different magnitudes within the same half cycle of discharge. The time resolution of the soft x-ray is achieved by means of scintillator detector. The detected x-ray pulse during the first half cycle of discharge had a double peaks with different structures. All the experimental results present in this paper showed that the plasma bulk propagated in the expansion chamber, consists of two-groups. 6 fig

  3. Leapfrogging of multiple coaxial viscous vortex rings

    International Nuclear Information System (INIS)

    Cheng, M.; Lou, J.; Lim, T. T.

    2015-01-01

    A recent theoretical study [Borisov, Kilin, and Mamaev, “The dynamics of vortex rings: Leapfrogging, choreographies and the stability problem,” Regular Chaotic Dyn. 18, 33 (2013); Borisov et al., “The dynamics of vortex rings: Leapfrogging in an ideal and viscous fluid,” Fluid Dyn. Res. 46, 031415 (2014)] shows that when three coaxial vortex rings travel in the same direction in an incompressible ideal fluid, each of the vortex rings alternately slips through (or leapfrogs) the other two ahead. Here, we use a lattice Boltzmann method to simulate viscous vortex rings with an identical initial circulation, radius, and separation distance with the aim of studying how viscous effect influences the outcomes of the leapfrogging process. For the case of two identical vortex rings, our computation shows that leapfrogging can be achieved only under certain favorable conditions, which depend on Reynolds number, vortex core size, and initial separation distance between the two rings. For the case of three coaxial vortex rings, the result differs from the inviscid model and shows that the second vortex ring always slips through the leading ring first, followed by the third ring slipping through the other two ahead. A simple physical model is proposed to explain the observed behavior

  4. Microminiature coaxial cable and methods manufacture

    Science.gov (United States)

    Bongianni, W.L.

    1986-04-08

    A coaxial cable is provided having a ribbon inner conductor surrounded by a dielectric and a circumferential conductor. The coaxial cable may be microminiature comprising a very thin ribbon strip conductor from between 5 to 15 [mu]m thick and from 150 to 200 [mu]m wide, having a surrounding foamed dielectric or parylene applied thereon by a vapor plasma process and an outer conductor of an adhering high conductivity metal vacuum deposited on the dielectric. Alternately the foam dielectric embodiment may have a contiguous parylene coating applied adjacent the inner conductor or the outer conductor or both. Also, the cable may be fabricated by forming a thin ribbon of strip conductive material into an inner conductor, applying thereabout a dielectric by spraying on a solution of polystyrene and polyethylene and then vacuum depositing and adhering high conductivity metal about the dielectric. The cable strength may be increased by adding glass microfilament fibers or glass microballoons to the solution of polystyrene and polyethylene. Further, the outer conductive layer may be applied by electroless deposition in an aqueous solution rather than by vacuum deposition. A thin coating of parylene is preferably applied to the outer conductor to prevent its oxidation and inhibit mechanical abrasion. 2 figs.

  5. A new matcher type between RFQ and IH-DTL for the GSI high current heavy ion prestripper linac

    International Nuclear Information System (INIS)

    Ratzinger, U.; Tiede, R.

    1996-01-01

    The adaptation of a RFQ beam to the typical requirements at the entrance of a drift tube linac is rather difficult at high intensities and high A/q values. The high focusing power needed for such a matcher can be provided by a conventional array with rather large quadrupoles and rebuncher cavities only. Many problems arising from such a design can be avoided by using an element which is focusing in transverse and longitudinal direction at the same time, that is a short RFQ ('Super Lens') with 10 cells typically and a larger aperture as compared to the main RFQ. A xy-steerer and a short quadrupole doublet with small aperture were added to gain flexibility with regard to beam mismatch and misalignment corrections. This new concept is realised for the GSI 15 mA U 4+ injector, which is under construction. Beam dynamics calculations are presented and compared with results for a conventional solution consisting of a rebuncher and a quadrupole triplet. (author)

  6. Needleless coaxial electrospinning: A novel approach to mass production of coaxial nanofibers.

    Czech Academy of Sciences Publication Activity Database

    Vysloužilová, L.; Buzgo, Matej; Pokorný, P.; Chvojka, J.; Míčková, Andrea; Rampichová, Michala; Kula, J.; Pejchar, K.; Bílek, M.; Lukáš, D.; Amler, Evžen

    2017-01-01

    Roč. 516, 1-2 (2017), s. 293-300 ISSN 0378-5173 R&D Projects: GA ČR(CZ) GA15-15697S; GA MŠk(CZ) LO1508; GA MŠk(CZ) LO1309 Institutional support: RVO:68378041 Keywords : core- shell nanofibers * coaxial electrospinning * needleless electrospinning Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Nano-materials (production and properties) Impact factor: 3.649, year: 2016

  7. Nanoscale devices based on plasmonic coaxial waveguide resonators

    Science.gov (United States)

    Mahigir, A.; Dastmalchi, P.; Shin, W.; Fan, S.; Veronis, G.

    2015-02-01

    Waveguide-resonator systems are particularly useful for the development of several integrated photonic devices, such as tunable filters, optical switches, channel drop filters, reflectors, and impedance matching elements. In this paper, we introduce nanoscale devices based on plasmonic coaxial waveguide resonators. In particular, we investigate threedimensional nanostructures consisting of plasmonic coaxial stub resonators side-coupled to a plasmonic coaxial waveguide. We use coaxial waveguides with square cross sections, which can be fabricated using lithography-based techniques. The waveguides are placed on top of a silicon substrate, and the space between inner and outer coaxial metals is filled with silica. We use silver as the metal. We investigate structures consisting of a single plasmonic coaxial resonator, which is terminated either in a short or an open circuit, side-coupled to a coaxial waveguide. We show that the incident waveguide mode is almost completely reflected on resonance, while far from the resonance the waveguide mode is almost completely transmitted. We also show that the properties of the waveguide systems can be accurately described using a single-mode scattering matrix theory. The transmission and reflection coefficients at waveguide junctions are either calculated using the concept of the characteristic impedance or are directly numerically extracted using full-wave three-dimensional finite-difference frequency-domain simulations.

  8. Splitting Ward identity

    Energy Technology Data Exchange (ETDEWEB)

    Safari, Mahmoud [Institute for Research in Fundamental Sciences (IPM), School of Particles and Accelerators, P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

    2016-04-15

    Within the background-field framework we present a path integral derivation of the splitting Ward identity for the one-particle irreducible effective action in the presence of an infrared regulator, and make connection with earlier works on the subject. The approach is general in the sense that it does not rely on how the splitting is performed. This identity is then used to address the problem of background dependence of the effective action at an arbitrary energy scale. We next introduce the modified master equation and emphasize its role in constraining the effective action. Finally, application to general gauge theories within the geometric approach is discussed. (orig.)

  9. Splitting Ward identity

    International Nuclear Information System (INIS)

    Safari, Mahmoud

    2016-01-01

    Within the background-field framework we present a path integral derivation of the splitting Ward identity for the one-particle irreducible effective action in the presence of an infrared regulator, and make connection with earlier works on the subject. The approach is general in the sense that it does not rely on how the splitting is performed. This identity is then used to address the problem of background dependence of the effective action at an arbitrary energy scale. We next introduce the modified master equation and emphasize its role in constraining the effective action. Finally, application to general gauge theories within the geometric approach is discussed. (orig.)

  10. Coaxial Compound Helicopter for Confined Urban Operations

    Science.gov (United States)

    Johnson, Wayne; Elmore, Joshua F.; Keen, Ernest B.; Gallaher, Andrew T.; Nunez, Gerardo F.

    2016-01-01

    A rotorcraft was designed for military operations in a confined urban environment. The specifications included major increases in useful load, range, and speed relative current aircraft capabilities, with a size constraint based on the dimensions of urban streets and intersections. Analysis showed that this combination of requirements is best satisfied by a coaxial main-rotor configuration, with lift compounding to off-load the rotors at high speed, and ducted fans under the rotor disk for propulsion. The baseline design is described, and the aircraft performance is summarized for utility, attack, MEDEVAC, and cargo delivery missions. The impact on size and performance is examined for a number of excursions, including lift-offset main rotors. Technology development required to achieve this advance in capability is recommended.

  11. Coaxial tube array space transmission line characterization

    International Nuclear Information System (INIS)

    Switzer, C.A.; Bents, D.J.

    1987-01-01

    The coaxial tube array tether/transmission line used to connect an SP-100 nuclear power system to the space station was characterized over the range of reactor-to-platform separation distances of 1 to 10 km. Characterization was done with respect to array performance, physical dimensions and masses. Using a fixed design procedure, a family of designs was generated for the same power level (300 kWe), power loss (1.5 percent), and meteoroid survival probability (99.5 percent over 10 yr). To differentiate between vacuum insulated and gas insulated lines, two different maximum values of the E field were considered: 20 kV/cm (appropriate to vacuum insulation) and 50 kV/cm (compressed SF6). Core conductor, tube, bumper, standoff, spacer and bumper support dimensions, and masses were also calculated. The results of the characterization show mainly how transmission line size and mass scale with reactor-to-platform separation distance

  12. Coaxial direct-detection lidar-system

    DEFF Research Database (Denmark)

    2014-01-01

    The invention relates to a coaxial direct-detection LIDAR system for measuring velocity, temperature and/or particulate density. The system comprises a laser source for emitting a laser light beam having a lasing center frequency along an emission path. The system further comprises an optical....... Finally, the system comprises a detector system arranged to receive the return signal from the optical delivery system, the detector system comprising a narrowband optical filter and a detector, the narrowband optical filter having a filter center frequency of a pass-band, wherein the center lasing...... frequency and/or the center filter frequency may be scanned. The invention further relates to an aircraft airspeed measurement device, and a wind turbine airspeed measurement device comprising the LIDAR system....

  13. Dynamics of a coaxial plasma gun

    International Nuclear Information System (INIS)

    Raadu, M.A.

    1977-01-01

    The dynamics of an ionizing wave in a coaxial plasma gun with an azimuthal bias magnetic field is analysed in a theoretical model. Only the radial dependence is treated and instead of including a treatment of the energy balance two separate physical assumptions are made. In the first case it is assumed that the total internal electric field is given by the critical ionization velocity condition and in the second that the ionization rate is constant. For consistency wall sheaths are assumed to match the internal plasma potential to that of the walls. On the basis of momentum and particle balance the radial dependence of the electron density, current density, electric field and drift velocity are found. An electron source is required at the cathode and the relative contribution from ionization within the plasma is deduced. The assumption that there are no ion sources at the electrodes leads to a restriction on the possible values of the axial electric field. (Auth.)

  14. Operation of a CW high power RFQ test cavity: The CRNL 'sparkers'

    International Nuclear Information System (INIS)

    Hutcheon, R.M.; Schriber, S.O.; Brown, J.C.; Clements, D.W.; Campbell, H.F.; McMichael, G.E.; De Jong, M.S.

    1984-01-01

    A 270 MHz RFQ structure with 365 mm long unmodulated vanes and a 2.5 mm minimum vane-to-vane gap was used to study cw operation at surface fields in excess of 30 MV/m. The brazed OFHC solid copper structure is flood cooled and couples rf power by a drive 100p at the centre of one quadrant. Surface electric fields equivalent to twice the Kilpatrick limit were obtained at 39 kW power. The structure was rapidly conditioned with alternating periods of pulsed and cw operation to levels above 45 kW. Bremsstrahlung end point energies were used as a measure of peak vane-to-vane voltage. Several interesting observations have been made. Glowing pinpoints of light were seen near the vane tips, some extinguishing with time, others appearing - but their number and intensity increasing with rf power. Microdischarges were seen, consisting of very small localized flashes of light between the vane tips, usually accompanied by a complete collapse and re-establishment of the structure rf field over a 20 μs interval. The frequency of field collapses varied with power but was independent of gas pressure and species up to 4x10 -3 Pa. As structure power was increased above the conditioned level, a rapid succession of microdischarges would occur, increasing the reflected power beyond the fast trip level. (orig.)

  15. Co-axial electrodes gun characteristics

    International Nuclear Information System (INIS)

    Masoud, M.M.; Soliman, H.M.

    1981-01-01

    A coaxial electrodes gun is constructed with inner electrode diameter of 3.2 cm; outer electrode diameter of 6.6 cm and length of 25 cm it is connected to a condenser bank which delivers 4 K joule stored energy. The maximum power of the discharge is equal to 4.5x10 4 K watt; for 5 KV charging voltage. The inductance showed two main peak values of 0.257μH and 0.27μH. Theoretical calculations using one-dimension-single fluid model is μ sed, which shows that the maximum acceleration is at 0.5 sec, and the gas breakdown takes place at the gun breech; at the start of the discharge, will leave the gun after 1.625μ sec, also the drift velocity, the force and the magnetic field are given. The measured results show quite reasonable agreement with the calculations for most of the results, and the position of the plasma sheath inside the gun slightly deviated from the theoretical calculations due to viscosity and wall interaction, as well as other parameters which did not be take into consideration. The plasma current density of the sheath has its maximum value at Z=18 cm, the plasma will leave the coaxial source after 1.5μ sec, from the start of the discharge, which conferms with the theoretical model. Resistance of the gas between the electrodes, changes with time according to the particle injected from this source, and the maximum efficiency of the installation for charging voltage 5kV and pressure 80μ Hg is at approx.=10μ sec and 20.5μ sec

  16. Niobium coaxial quarter-wave cavities for the New Delhi booster linac

    International Nuclear Information System (INIS)

    Shepard, K.W.; Roy, A.; Potukuchi, P.N.

    1993-01-01

    This paper reports the design and construction status of a prototype superconducting niobium accelerating structure consisting of a pair of quarter-wave coaxial-line cavities which are strongly coupled with a superconducting loop. Quarter-wave resonators are two-gap accelerating structures and are relatively short, so that a large number of independently-phased cavities is required for a linac. Strongly coupling several cavities can reduce the number of independently-phased elements, but at the cost of reducing the range of useful velocity acceptance for each element. Coupling two cavities splits the accelerating rf eigenmode into two resonant modes each of which covers a portion of the full velocity acceptance range of the original single cavity mode. Using both of these resonant modes makes feasible the use of coupled cavity pairs for a linac with little loss m velocity acceptance. Design details for the niobium cavity pair and the results of preliminary tests of multipacting behavior are discussed

  17. Niobium coaxial quarter-wave cavities for the New Delhi booster linac

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, K.W. [Argonne National Lab., IL (United States); Roy, A.; Potukuchi, P.N. [Nuclear Science Centre, New Delhi (India)

    1993-07-01

    This paper reports the design and construction status of a prototype superconducting niobium accelerating structure consisting of a pair of quarter-wave coaxial-line cavities which are strongly coupled with a superconducting loop. Quarter-wave resonators are two-gap accelerating structures and are relatively short, so that a large number of independently-phased cavities is required for a linac. Strongly coupling several cavities can reduce the number of independently-phased elements, but at the cost of reducing the range of useful velocity acceptance for each element. Coupling two cavities splits the accelerating rf eigenmode into two resonant modes each of which covers a portion of the full velocity acceptance range of the original single cavity mode. Using both of these resonant modes makes feasible the use of coupled cavity pairs for a linac with little loss m velocity acceptance. Design details for the niobium cavity pair and the results of preliminary tests of multipacting behavior are discussed.

  18. Multipactor Mitigation in Coaxial Lines by Means of Permanent Magnets

    CERN Document Server

    Gonzalez-Iglesias, D; Anza, S; Vague, J; Gimeno, B; Boria, V E; Raboso, D; Vicente, C; Gil, J; Caspers, F; Conde, L

    2014-01-01

    The main aim of this paper is the analysis of the feasibility of employing permanent magnets for the multipactor mitigation in a coaxial waveguide. First, the study of a coaxial line immersed in a uniform axial magnetic field shows that multipactor can be suppressed at any RF frequency if the external magnetic field is strong enough. Both theoretical simulations and experimental tests validate this statement. Next, multipactor breakdown of a coaxial line immersed in a hollow cylindrical permanent magnet is analyzed. Numerical simulations show that multipactor can be suppressed in a certain RF frequency range. The performed experimental test campaign demonstrates the capability of the magnet to avoid the multipactor electron multiplication process.

  19. The Splitting Loope

    Science.gov (United States)

    Wilkins, Jesse L. M.; Norton, Anderson

    2011-01-01

    Teaching experiments have generated several hypotheses concerning the construction of fraction schemes and operations and relationships among them. In particular, researchers have hypothesized that children's construction of splitting operations is crucial to their construction of more advanced fractions concepts (Steffe, 2002). The authors…

  20. The Splitting Group

    Science.gov (United States)

    Norton, Anderson; Wilkins, Jesse L. M.

    2012-01-01

    Piagetian theory describes mathematical development as the construction and organization of mental operations within psychological structures. Research on student learning has identified the vital roles of two particular operations--splitting and units coordination--play in students' development of advanced fractions knowledge. Whereas Steffe and…

  1. Studies on coaxial circular array for underwater transducer applications

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.

    of the coaxial array from the next stage of investigation during which a hybrid formulation is developed to provide a computationally efficient method of calculating impedance. Different sidelobe suppression techniques including uniform and nonuniform excitations...

  2. Investigation on carbon nanomaterials: Coaxial CNT-cylinders and ...

    Indian Academy of Sciences (India)

    Wintec

    carbon cylinders of CNT stacks have been formed directly inside the quartz tube. Another study is ... producing CNTs have been devised including electric arc evaporation ... process of coaxial carbon cylinder have already been de- scribed by ...

  3. Design and experimental results of coaxial circuits for gyroklystron amplifiers

    International Nuclear Information System (INIS)

    Flaherty, M.K.E.; Lawson, W.; Cheng, J.; Calame, J.P.; Hogan, B.; Latham, P.E.; Granatstein, V.L.

    1994-01-01

    At the University of Maryland high power microwave source development for use in linear accelerator applications continues with the design and testing of coaxial circuits for gyroklystron amplifiers. This presentation will include experimental results from a coaxial gyroklystron that was tested on the current microwave test bed, and designs for second harmonic coaxial circuits for use in the next generation of the gyroklystron program. The authors present test results for a second harmonic coaxial circuit. Similar to previous second harmonic experiments the input cavity resonated at 9.886 GHz and the output frequency was 19.772 GHz. The coaxial insert was positioned in the input cavity and drift region. The inner conductor consisted of a tungsten rod with copper and ceramic cylinders covering its length. Two tungsten rods that bridged the space between the inner and outer conductors supported the whole assembly. The tube produced over 20 MW of output power with 17% efficiency. Beam interception by the tungsten rods resulted in minor damage. Comparisons with previous non-coaxial circuits showed that the coaxial configuration increased the parameter space over which stable operation was possible. Future experiments will feature an upgraded modulator and beam formation system capable of producing 300 MW of beam power. The fundamental frequency of operation is 8.568 GHz. A second harmonic coaxial gyroklystron circuit was designed for use in the new system. A scattering matrix code predicts a resonant frequency of 17.136 GHz and Q of 260 for the cavity with 95% of the outgoing microwaves in the desired TE032 mode. Efficiency studies of this second harmonic output cavity show 20% expected efficiency. Shorter second harmonic output cavity designs are also being investigated with expected efficiencies near 34%

  4. ''Theta gun,'' a multistage, coaxial, magnetic induction projectile accelerator

    International Nuclear Information System (INIS)

    Burgess, T.J.; Duggin, B.W.; Cowan, M. Jr.

    1985-11-01

    We experimentally and theoretically studied a multistage coaxial magnetic induction projectile accelerator. We call this system a ''theta gun'' to differentiate it from other coaxial accelerator concepts such as the mass driver. We conclude that this system can theoretically attain railgun performance only for large caliber or very high injection velocity and, even then, only for long coil geometry. Our experiments with a three-stage, capactor bank-driven accelerator are described. The experiments are modeled with a 1-1/2 dimensional equivalent circuit-hydrodynamics code which is also described. We derive an expression for the conditions of coaxial accelerator-railgun ''velocity breakeven'' in the absence of ohmic and hydrodynamic effects. This, in conjunction with an expression for the magnetic coupling coefficient, defines a set of geometric relations which the coaxial system must simultaneously satisfy. Conclusions concerning both the existence and configuration of a breakeven coaxial system follow from this requirement. The relative advantages and disadvantages of the coaxial induction projectile accelerator, previously cited in the literature, are critiqued from the viewpoint of our analysis and experimental results. We find that the advantages vis-a-vis the railgun have been overstated. 13 refs., 17 figs

  5. Split warhead simultaneous impact

    Directory of Open Access Journals (Sweden)

    Rahul Singh Dhari

    2017-12-01

    Full Text Available A projectile system is proposed to improve efficiency and effectiveness of damage done by anti-tank weapon system on its target by designing a ballistic projectile that can split into multiple warheads and engage a target at the same time. This idea has been developed in interest of saving time consumed from the process of reloading and additional number of rounds wasted on target during an attack. The proposed system is achieved in three steps: Firstly, a mathematical model is prepared using the basic equations of motion. Second, An Ejection Mechanism of proposed warhead is explained with the help of schematics. Third, a part of numerical simulation which is done using the MATLAB software. The final result shows various ranges and times when split can be effectively achieved. With the new system, impact points are increased and hence it has a better probability of hitting a target.

  6. Isospin splittings of baryons

    International Nuclear Information System (INIS)

    Varga, Kalman; Genovese, Marco; Richard, Jean-Marc; Silvestre-Brac, Bernard

    1998-01-01

    We discuss the isospin-breaking mass differences among baryons, with particular attention in the charm sector to the Σ c + -Σ c 0 , Σ c ++ -Σ c 0 , and Ξ c + -Ξ c 0 splittings. Simple potential models cannot accommodate the trend of the available data on charm baryons. More precise measurements would offer the possibility of testing how well potential models describe the non-perturbative limit of QCD

  7. (O)Mega split

    Energy Technology Data Exchange (ETDEWEB)

    Benakli, Karim; Darmé, Luc; Goodsell, Mark D. [Sorbonne Universités, UPMC Univ Paris 06, UMR 7589,LPTHE, F-75005, Paris (France); CNRS, UMR 7589,LPTHE, F-75005, Paris (France)

    2015-11-16

    We study two realisations of the Fake Split Supersymmetry Model (FSSM), the simplest model that can easily reproduce the experimental value of the Higgs mass for an arbitrarily high supersymmetry scale M{sub S}, as a consequence of swapping higgsinos for equivalent states, fake higgsinos, with suppressed Yukawa couplings. If the LSP is identified as the main Dark matter component, then a standard thermal history of the Universe implies upper bounds on M{sub S}, which we derive. On the other hand, we show that renormalisation group running of soft masses aboveM{sub S} barely constrains the model — in stark contrast to Split Supersymmetry — and hence we can have a “Mega Split” spectrum even with all of these assumptions and constraints, which include the requirements of a correct relic abundance, a gluino life-time compatible with Big Bang Nucleosynthesis and absence of signals in present direct detection experiments of inelastic dark matter. In an appendix we describe a related scenario, Fake Split Extended Supersymmetry, which enjoys similar properties.

  8. Study of 750 J plasma coaxial accelerator

    International Nuclear Information System (INIS)

    Mehanna, E.A.; Hassouba, M.A; Abd al-halim, M.A.

    2009-01-01

    A 750 J plasma coaxial accelerator is used to produce plasma using air at 0.2 torr pressure and 8 kv charging voltage. The discharge current and voltage traces showed that the total circuit inductance was about 1750 μH. The experimental results showed that the plasma sheath reached the muzzle after 6 μs with velocity equal to 4 cm/μs, after then it decreased, while the simulation model showed that the plasma sheath reaches the muzzle with velocity of 3 cm/μs and after one microsecond it increases to reach about 4 cm/μs after 12 μs then it decreased. The plasma temperature measurements showed that the plasma sheath reached the muzzle with temperature of about 9 eV and increase to reach about 12 eV after 8.5 μs then after it decrease. The simulation model showed that the plasma temperature at the muzzle is about 10.5 eV and continue to increase to reach 17.5 eV after 12 μs then it decrease

  9. Injection study of the Radiance 330 synchrotron with a 1.6 MeV RFQ linac

    Science.gov (United States)

    Wang, F.; Flanz, J.; Hamm, R.

    2012-09-01

    The ProTom Radiance 330 proton radiotherapy system provides the most advanced proton delivery capability to date. It supports true three-dimensional beam scanning with dynamic energy and intensity modulation. Most of the protons extracted from the synchrotron are used to treat the patient, which results in minimal neutron background in the treatment room. The patient dose rate depends upon the number of protons injected and the acceleration cycle time. Therefore, one can boost the dose rate by increasing the beam intensity at injection. Improvements to the existing tandem accelerator injector are already underway. However, an alternative way to attain higher intensity beam is to use an RFQ linac as an injector. To this end, a novel 1.6 MeV RFQ linac has been designed to specifically satisfy the small energy acceptance limits of the synchrotron. Simulations of the beam line optics and injection matching to the synchrotron have been performed using the computer codes PARMILA and TRACE-3D to determine if an additional bunching cavity is needed. Assessments of the space charge limit at the relatively low injection energy of 1.6 MeV and RF capture simulations have also been performed. Results of these studies are presented.

  10. Experimental studies of coaxial plasma gun current

    International Nuclear Information System (INIS)

    Price, D.W.

    1988-01-01

    In this investigation of a coaxial plasma gun, plasma sheath currents and related behavior are examined. Plasma behavior in the gun affects gun characteristics. Plasma gun applications are determined by the plasma behavior. The AFWL PUFF capacitor bank (72 μF, 29 nH, 120 kV) drives the plasma gun using a deuterium fill gas. The gas breakdown site is isolated from the dielectric/vacuum interface in the AFWL system. Two gas values deliver gas in the system. The first delivers gas from the gun breech and the second optional valve delivers gas to the gun muzzle. Currents and voltages are measured by Rogowski coils, B probes and capacitive voltage probes. A O-D slug model is used to predict the current, inductance, gun voltage and plasma sheath velocity. The slug model assumes the sheath transits the gun with all mass in the sheath. In the snowplow mode, the plasma sheath is thin with a sharp current rise and drop. Our system operated in a transition mode between the snowplow and deflagration modes with early snowplow behavior and late deflagration behavior. Neutrons are produced in a plasma pinch at the gun muzzle, indicating snowplow behavior. The slug theory models overall gun behavior to experimental accuracy. Experimental results are compared to four theories for plasma sheath velocities: the Alfven collisionally limited model, the Rosenbluth model, the Fishbine saturated model and a single particle drift model. Experimental velocities vary from 10 5 to 10 6 m/s. Only the single particle drift and the slug model calculations are of the right magnitude (8 x 10 5 m/s). The Fishbine and the Rosenbluth models predict slower velocities (2 x 10 5 m/s). The Alfven model is not applicable to this system

  11. Electrical properties of a co-axial plasma gun

    International Nuclear Information System (INIS)

    Allam, T.M.Y.

    1997-01-01

    The main interest of this work is to study the power discharge of capacitor bank through a coaxial electrodes system. Such arrangement is called the coaxial gun or coaxial accelerator. It is used in jet propulsion and in triggering of discharge in turbo engines or in plasma combustion arrangement. The main goal is to find out the efficiency of the system in both cases. coaxial plasma gun system has been constructed for this course of study. The plasma gun system consists of the plasma gun tube and the discharge chamber, the capacitor bank, the triggering system the vacuum system, the power supply, and safety and dumping system. Simple and efficient diagnostic techniques were used to measure the different parameters concerning the coaxial discharge system such as the Rogowski loop, the voltage divider, the magnetic probes, the double electric probe. Results were obtained using argon gas with an operating pressure ranging from 0.1 torr to 1 torr. The peak discharge current in the first half cycle was 44 K A with rise time of 6.25 μs for a bank charging voltage of 10 kv and gas pressure of 0.9 torr. 4-26 figs., 4-8 tabs., 33 refs

  12. Heat removal capability of divertor coaxial tube assembly

    International Nuclear Information System (INIS)

    Shibui, Masanao; Nakahira, Masataka; Tada, Eisuke; Takatsu, Hideyuki

    1994-05-01

    To deal with high power flowing in the divertor region, an advanced divertor concept with gas target has been proposed for use in ITER/EDA. The concept uses a divertor channel to remove the radiated power while allowing neutrals to recirculate. Candidate channel wall designs include a tube array design where many coaxial tubes are arranged in the toroidal direction to make louver. The coaxial tube consists of a Be protection tube encases many supply tubes wound helically around a return tube. V-alloy and hardened Cu-alloy have been proposed for use in the supply and return tubes. Some coolants have also been proposed for the design including pressurized He and liquid metals, because these coolants are consistent with the selection of coolants for the blanket and also meet the requirement of high temperature operation. In the coaxial tube design, the coolant area is restricted and brittle Be material is used under severe thermal cyclings. Thus, to obtain the coaxial tube with sufficient safety margin for the expected fusion power excursion, it is essential to understand its applicability limit. The paper discusses heat removal capability of the coaxial tube and recommends some design modifications. (author)

  13. High power X-band coaxial amplifier experiments

    International Nuclear Information System (INIS)

    Davis, T.J.; Nation, J.A.

    1991-01-01

    Studies are continuing on the development of X-band coaxial microwave amplifiers as a source for next generation linear colliders. Coaxial amplifiers employ an annular electron beam propagating between inner and outer drift tube conductors, a configuration which allows large increases in beam current over standard pencil beam amplifiers. Large average diameter systems may still be used without mode competition since TM mode cutoff frequencies are controlled by the separation between conductors. A number of amplifier configurations are being studied, all primed by a driven initial cavity which resonates around 9 GHz. Simple theory of coaxial systems and particle-in-cell simulations are presented, as well as initial experimental results using a 420 keV, 7-8 kA, 9 cm diameter annular beam

  14. Coaxial silver nanowire network core molybdenum oxide shell supercapacitor electrodes

    International Nuclear Information System (INIS)

    Yuksel, Recep; Coskun, Sahin; Unalan, Husnu Emrah

    2016-01-01

    We present a new hybrid material composed of molybdenum (IV) oxide (MoO 2 ) shell on highly conducting silver nanowire (Ag NW) core in the network form for the realization of coaxial Ag NW/MoO 2 nanocomposite supercapacitor electrodes. Ag NWs were simply spray coated onto glass substrates to form conductive networks and conformal MoO 2 layer was electrodeposited onto the Ag NW network to create binder-free coaxial supercapacitor electrodes. Combination of Ag NWs and pseudocapacitive MoO 2 generated an enhanced electrochemical energy storage capacity and a specific capacitance of 500.7 F/g was obtained at a current density of 0.25 A/g. Fabricated supercapacitor electrodes showed excellent capacity retention after 5000 cycles. The methods and the design investigated herein open a wide range of opportunities for nanowire based coaxial supercapacitors.

  15. Coaxial Thermoplastic Elastomer-Wrapped Carbon Nanotube Fibers for Deformable and Wearable Strain Sensors

    KAUST Repository

    Zhou, Jian; Xu, Xuezhu; Xin, Yangyang; Lubineau, Gilles

    2018-01-01

    performances in these design requirements. Here, achieving highly stretchable and sensitive strain sensors by using a coaxial structure, prepared via coaxial wet spinning of thermoplastic elastomer-wrapped carbon nanotube fibers, is proposed. The sensors attain

  16. Geometrical splitting in Monte Carlo

    International Nuclear Information System (INIS)

    Dubi, A.; Elperin, T.; Dudziak, D.J.

    1982-01-01

    A statistical model is presented by which a direct statistical approach yielded an analytic expression for the second moment, the variance ratio, and the benefit function in a model of an n surface-splitting Monte Carlo game. In addition to the insight into the dependence of the second moment on the splitting parameters the main importance of the expressions developed lies in their potential to become a basis for in-code optimization of splitting through a general algorithm. Refs

  17. Swirl Coaxial Injector Testing with LOX/RP-J

    Science.gov (United States)

    Greene, Sandra Elam; Casiano, Matt

    2013-01-01

    Testing was conducted at NASA fs Marshall Space Flight Center (MSFC) in the fall of 2012 to evaluate the operation and performance of liquid oxygen (LOX) and kerosene (RP ]1) in an existing swirl coaxial injector. While selected Russian engines use variations of swirl coaxial injectors, component level performance data has not been readily available, and all previously documented component testing at MSFC with LOX/RP ]1 had been performed using a variety of impinging injector designs. Impinging injectors have been adequate for specific LOX/RP ]1 engine applications, yet swirl coaxial injectors offer easier fabrication efforts, providing cost and schedule savings for hardware development. Swirl coaxial elements also offer more flexibility for design changes. Furthermore, testing with LOX and liquid methane propellants at MSFC showed that a swirl coaxial injector offered improved performance compared to an impinging injector. So, technical interest was generated to see if similar performance gains could be achieved with LOX/RP ]1 using a swirl coaxial injector. Results would allow such injectors to be considered for future engine concepts that require LOX/RP ]1 propellants. Existing injector and chamber hardware was used in the test assemblies. The injector had been tested in previous programs at MSFC using LOX/methane and LOX/hydrogen propellants. Minor modifications were made to the injector to accommodate the required LOX/RP ]1 flows. Mainstage tests were performed over a range of chamber pressures and mixture ratios. Additional testing included detonated gbombs h for stability data. Test results suggested characteristic velocity, C*, efficiencies for the injector were 95 ]97%. The injector also appeared dynamically stable with quick recovery from the pressure perturbations generated in the bomb tests.

  18. Design, development and operational experience of radio frequency (RF) power systems/technologies for LEHIPA and 400 keV RFQ

    International Nuclear Information System (INIS)

    Pande, Manjiri; Shrotriya, Sandip; Patel, Niranjan

    2015-01-01

    The important technology development for ion accelerators of 'accelerator driven sub critical reactor system (ADS) is being done under the program of Department of Atomic Energy (DAE). In BARC (BARC) of DAE, technology development of 400 keV radio frequency quadrupole (RFQ) accelerator is done and a 20 MeV - low energy high intensity proton accelerator (LEHIPA) is under development. A 400 KeV deuteron RFQ accelerator is already developed at BARC and its 60 kW radio frequency (RF) power system required for beam acceleration has been designed, developed and tested both in CW mode and in pulse mode for full power of 60 leW. It has been successfully integrated with RFQ via 6-1/8'', 50 ohm RF transmission line, to accelerate proton beam up to 200 KeV energy and deuteron beam to 400 KeV energy. LEHIPA requires about 3 MW of RF power for its operation. So, three 1 MW, 352 MHz RF systems based on klystron will be developed for RFQ and two DTLs. The klystron based RF system for 3 MeV RFQ is under commissioning. Its various subsystems like energy less and insulated gate bipolar transistor (IGBT) based high voltage and low voltage bias supplies, a critical and fast protection and control system - handling various types of field signals, fast acting hard wired instrumentation circuits for critical signals, 100 kV crowbar with its circuits, pulsing circuits and RF circuits have been successfully designed, developed and integrated with klystron. Latest technology development of solid state RF amplifiers at 325 MHz and 350 MHz for normal and super conducting accelerators has attained a certain power level. This paper will discuss all these high power RF systems in detail. (author)

  19. Structural aspects of coaxial oxy-fuel flames

    Science.gov (United States)

    Ditaranto, M.; Sautet, J. C.; Samaniego, J. M.

    Oxy-fuel combustion has been proven to increase thermal efficiency and to have a potential for NOx emission reduction. The study of 25-kW turbulent diffusion flames of natural gas with pure oxygen is undertaken on a coaxial burner with quarl. The structural properties are analysed by imaging the instantaneous reaction zone by OH* chemiluminescence and measuring scalar and velocity profiles. The interaction between the flame front and the shear layers present in the coaxial jets depends on the momentum ratio which dictates the turbulent structure development. Flame length and NOx emission sensitivity to air leaks in the combustion chamber are also investigated.

  20. Experimental seismic test of fluid coupled co-axial cylinders

    International Nuclear Information System (INIS)

    Chu, M.L.; Brown, S.J.; Lestingi, J.F.

    1979-01-01

    The dynamic response of fluid coupled coaxial cylindrical shells is of interest to the nuclear industry with respect to the seismic design of the reactor vessel and thermal liner. The experiments described present a series of tests which investigate the effect of the annular clearance between the cylinders (gap) on natural frequency, damping, and seismic response of both the inner and outer cylinders. The seismic input is a time history base load to the flexible fluid filled coaxial cylinders. The outer cylinder is elastically supported at both ends while the inner cylinder is supported only at the base (lower) end

  1. Snaps to Connect Coaxial and Microstrip Lines in Wearable Systems

    Directory of Open Access Journals (Sweden)

    Tiiti Kellomäki

    2012-01-01

    Full Text Available Commercial snaps (clothing fasteners can be used to connect a coaxial cable to a microstrip line. This is useful in the context of wearable antennas, especially in consumer applications and disposable connections. The measured S-parameters of the transition are presented, and an equivalent circuit and approximate equations are derived for system design purposes. The proposed connection is usable up to 1.5 GHz (10 dB return loss condition, and the frequency range can be extended to 2 GHz if a thinner, more flexible coaxial cable is used.

  2. Leaky coaxial cable signal transmission for remote facilities

    Science.gov (United States)

    Smith, S. F.; Crutcher, R. I.

    To develop reliable communications methods to meet the rigorous requirements for nuclear hot cells and similar environments, including control of cranes, transporters, and advanced servomanipulators, the Consolidated Fuel Reprocessing Program (CFRP) at Oak Ridge National Laboratory (ORNL) has conducted extensive tests of numerous technologies to determine their applicability to remote operations. To alleviate the need for large bundles of cables that must accommodate crane/transporter motion relative to the boundaries of the cell, several transmission techniques are available, including slotted-line radio-frequency couplers, infrared beams, fiber-optic cables, free-space microwave, and inductively coupled leaky coaxial cable. This paper discusses the general characteristics, mode of operation, and proposed implementation of leaky coaxial cable technology in a waste-handling facility scheduled to be built in the near future at ORNL. In addition, specific system hardware based around the use of leaky coaxial cable is described in detail. Finally, data from a series of radiation exposure tests conducted by the CFRP on several samples of the basic leaky coaxial cable and associated connectors are presented.

  3. The breakdown phase in a coaxial plasma gun

    International Nuclear Information System (INIS)

    Donges, A.; Herziger, G.; Krompholz, H.; Ruehl, F.; Schoenbach, K.

    1980-01-01

    The electrical breakdown in a coaxial plasma gun was investigated by means of optical and electrical measurements. The optimum start and operation conditions of the gun turned out to be strongly dependent on material and length of the cylindrical insulator. (orig.)

  4. Initial Results from Coaxial Helicity Injection Experiments in NSTX

    International Nuclear Information System (INIS)

    Raman, R.; Jarboe, T.R.; Mueller, D.; Schaffer, M.J.; Maqueda, R.; Nelson, B.A.; Sabbagh, S.; Bell, M.; Ewig, R.; Fredrickson, E.; Gates, D.; Hosea, J.; Ji, H.; Kaita, R.; Kaye, S.M.; Kugel, H.; Maingi, R.; Menard, J.; Ono, M.; Orvis, D.; Paolette, F.; Paul, S.; Peng, M.; Skinner, C.H.; Wilgen, W.; Zweben, S.

    2001-01-01

    Coaxial Helicity Injection (CHI) has been investigated on the National Spherical Torus Experiment (NSTX). Initial experiments produced 130 kA of toroidal current without the use of the central solenoid. The corresponding injector current was 20 kA. Discharges with pulse lengths up to 130 ms have been produced

  5. Physical properties of compact toroids generated by a coaxial source

    Energy Technology Data Exchange (ETDEWEB)

    Henins, I.; Hoida, H.W.; Jarboe, T.R.; Linford, R.K.; Marshall, J.; McKenna, K.F.; Platts, D.A.; Sherwood, A.R.

    1980-01-01

    In the CTX experiments we have been studying CTs generated with a magnetized coaxial plasma gun. CTs have been generated in prolate and oblate cylindrically symmetric metallic flux conservers. The plasma and magnetic field properties are studied through the use of magnetic probes, Thomson scattering, interferometry, and spectroscopy.

  6. Coaxial fiber supercapacitor using all-carbon material electrodes.

    Science.gov (United States)

    Le, Viet Thong; Kim, Heetae; Ghosh, Arunabha; Kim, Jaesu; Chang, Jian; Vu, Quoc An; Pham, Duy Tho; Lee, Ju-Hyuck; Kim, Sang-Woo; Lee, Young Hee

    2013-07-23

    We report a coaxial fiber supercapacitor, which consists of carbon microfiber bundles coated with multiwalled carbon nanotubes as a core electrode and carbon nanofiber paper as an outer electrode. The ratio of electrode volumes was determined by a half-cell test of each electrode. The capacitance reached 6.3 mF cm(-1) (86.8 mF cm(-2)) at a core electrode diameter of 230 μm and the measured energy density was 0.7 μWh cm(-1) (9.8 μWh cm(-2)) at a power density of 13.7 μW cm(-1) (189.4 μW cm(-2)), which were much higher than the previous reports. The change in the cyclic voltammetry characteristics was negligible at 180° bending, with excellent cycling performance. The high capacitance, high energy density, and power density of the coaxial fiber supercapacitor are attributed to not only high effective surface area due to its coaxial structure and bundle of the core electrode, but also all-carbon materials electrodes which have high conductivity. Our coaxial fiber supercapacitor can promote the development of textile electronics in near future.

  7. Online monitoring of biofouling using coaxial stub resonator technique

    NARCIS (Netherlands)

    Hoog-Antonyuk, N.A.; Mayer, M.J.J.; Miedema, H.; Olthuis, Wouter; Tomaszweska, A.A.; Paulitsch-Fuchs, A.H.; van den Berg, Albert

    Here we demonstrate the proof-of-principle that a coaxial stub resonator can be used to detect early stages of biofilm formation. After promising field tests using a stub resonator with a stainless steel inner conductor as sensitive element, the sensitivity of the system was improved by using a

  8. Coaxial TW window for power couplers and multipactor considerations

    International Nuclear Information System (INIS)

    Hanus, X.; Mosnier, A.

    1996-01-01

    A Traveling Wave coaxial window has been studied for power couplers purposes. The main features, a reduced electrical field in the ceramic and its multipacting free shape are presented. Multipacting simulations results for other window geometries, using a conical or a cylindrical ceramic are also showed. (author)

  9. Evaluating efficiency of coaxial MLC VMAT plan for spine SBRT

    Energy Technology Data Exchange (ETDEWEB)

    Son, Sang Jun; Mun, Jun Ki; Kim, Dae Ho; Yoo, Suk Hyun [Dept. of Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2014-12-15

    The purpose of the study is to evaluate the efficiency of Coaxial MLC VMAT plan (Using 273° and 350° collimator angle) That the leaf motion direction aligned with axis of OAR (Organ at risk, It means spinal cord or cauda equine in this study.) compare to Universal MLC VMAT plan (using 30° and 330 ° collimator angle) for spine SBRT. The 10 cases of spine SBRT that treated with VMAT planned by Coaxial MLC and Varian TBX were enrolled. Those cases were planned by Eclipse (Ver. 10.0.42, Varian, USA), PRO3 (Progressive Resolution Optimizer 10.0.28) and AAA (Anisotropic Analytic Algorithm Ver. 10.0.28) with coplanar 260 ° arcs and 10MV FFF (Flattening filter free). Each arc has 273° and 350 ° collimator angle, respectively. The Universal MLC VMAT plans are based on existing treatment plans. Those plans have the same parameters of existing treatment plans but collimator angle. To minimize the dose difference that shows up randomly on optimizing, all plans were optimized and calculated twice respectively. The calculation grid is 0.2 cm and all plans were normalized to the target V100%=90%. The indexes of evaluation are V10Gy, D0.03cc, Dmean of OAR (Organ at risk, It means spinal cord or cauda equine in this study.), H.I (Homogeneity index) of the target and total MU. All Coaxial VMAT plans were verified by gamma test with Mapcheck2 (Sun Nuclear Co., USA), Mapphan (Sun Nuclear Co., USA) and SNC patient (Sun Nuclear Co., USA Ver 6.1.2.18513). The difference between the coaxial and the universal VMAT plans are follow. The coaxial VMAT plan is better in the V10Gy of OAR, Up to 4.1%, at least 0.4%, the average difference was 1.9% and In the D0.03cc of OAR, Up to 83.6 cGy, at least 2.2 cGy, the average difference was 33.3 cGy. In Dmean, Up to 34.8 cGy, at least -13.0 cGy, the average difference was 9.6 cGy that say the coaxial VMAT plans are better except few cases. H.I difference Up to 0.04, at least 0.01, the average difference was 0.02 and the difference of average

  10. NOx emission characteristics in turbulent hydrogen jet flames with coaxial air

    International Nuclear Information System (INIS)

    Moon, Hee Jang; Park, Yang Ho; Yoon, Young Bin

    2009-01-01

    The characteristics of NOx emissions in pure hydrogen nonpremixed jet flames with coaxial air are analyzed numerically for a wide range of coaxial air conditions. Among the models tested in simple nonpremixed jet flame, the one-half power scaling law could be reproduced only by the Model C using the HO 2 /H 2 O 2 reaction, implying the importance of chemical nonequilibrium effect. The flame length is reduced significantly by augmenting coaxial air, and could be represented as a function of the ratio of coaxial air to fuel velocity. Predicted EINOx scaling showed a good concordance with experimental data, and the overall one-half power scaling was observed in coaxial flames with Model C when flame residence time was defined with flame volume instead of a cubic of the flame length. Different level of oxygen mass fraction at the stoichiometric surface was observed as coaxial air was increased. These different levels imply that the coaxial air strengthens the nonequilibrium effect

  11. Split-illumination electron holography

    Energy Technology Data Exchange (ETDEWEB)

    Tanigaki, Toshiaki; Aizawa, Shinji; Suzuki, Takahiro; Park, Hyun Soon [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Inada, Yoshikatsu [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan); Matsuda, Tsuyoshi [Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Taniyama, Akira [Corporate Research and Development Laboratories, Sumitomo Metal Industries, Ltd., Amagasaki, Hyogo 660-0891 (Japan); Shindo, Daisuke [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan); Tonomura, Akira [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Okinawa Institute of Science and Technology, Graduate University, Onna-son, Okinawa 904-0495 (Japan); Central Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama 350-0395 (Japan)

    2012-07-23

    We developed a split-illumination electron holography that uses an electron biprism in the illuminating system and two biprisms (applicable to one biprism) in the imaging system, enabling holographic interference micrographs of regions far from the sample edge to be obtained. Using a condenser biprism, we split an electron wave into two coherent electron waves: one wave is to illuminate an observation area far from the sample edge in the sample plane and the other wave to pass through a vacuum space outside the sample. The split-illumination holography has the potential to greatly expand the breadth of applications of electron holography.

  12. Split-illumination electron holography

    International Nuclear Information System (INIS)

    Tanigaki, Toshiaki; Aizawa, Shinji; Suzuki, Takahiro; Park, Hyun Soon; Inada, Yoshikatsu; Matsuda, Tsuyoshi; Taniyama, Akira; Shindo, Daisuke; Tonomura, Akira

    2012-01-01

    We developed a split-illumination electron holography that uses an electron biprism in the illuminating system and two biprisms (applicable to one biprism) in the imaging system, enabling holographic interference micrographs of regions far from the sample edge to be obtained. Using a condenser biprism, we split an electron wave into two coherent electron waves: one wave is to illuminate an observation area far from the sample edge in the sample plane and the other wave to pass through a vacuum space outside the sample. The split-illumination holography has the potential to greatly expand the breadth of applications of electron holography.

  13. Two-Loop Splitting Amplitudes

    International Nuclear Information System (INIS)

    Bern, Z.

    2004-01-01

    Splitting amplitudes govern the behavior of scattering amplitudes at the momenta of external legs become collinear. In this talk we outline the calculation of two-loop splitting amplitudes via the unitarity sewing method. This method retains the simple factorization properties of light-cone gauge, but avoids the need for prescriptions such as the principal value or Mandelstam-Leibbrandt ones. The encountered loop momentum integrals are then evaluated using integration-by-parts and Lorentz invariance identities. We outline a variety of applications for these splitting amplitudes

  14. Two-loop splitting amplitudes

    International Nuclear Information System (INIS)

    Bern, Z.; Dixon, L.J.; Kosower, D.A.

    2004-01-01

    Splitting amplitudes govern the behavior of scattering amplitudes at the momenta of external legs become collinear. In this talk we outline the calculation of two-loop splitting amplitudes via the unitarity sewing method. This method retains the simple factorization properties of light-cone gauge, but avoids the need for prescriptions such as the principal value or Mandelstam-Leibbrandt ones. The encountered loop momentum integrals are then evaluated using integration-by-parts and Lorentz invariance identities. We outline a variety of applications for these splitting amplitudes

  15. The Digital Feedback RF Control System of the RFQ and DTL1 for 100 MeV Proton Linac of PEFP

    CERN Document Server

    Yu In Ha; Cho, Yong-Sub; Han, Yeung-Jin; Kang Heung Sik; Kim, Sung-Chul; Kwon, Hyeok-Jung; Park, In-Soo; Tae Kim, Do; Tae Seol, Kyung

    2005-01-01

    The 100 MeV Proton linear accelerator (Linac) for the PEFP (Proton Engineering Frontier Project) will include 1 RFQ and 1 DTL1 at 350 MHz as well as 7 DTL2 cavities at 700 MHz. The low level RF system with the digital feedback RF control provides the field control to accelerate a 20mA proton beam from 50 keV to 20 MeV with a RFQ and a DTL1 at 350M Hz. The FPGA-based digital feedback RF control system has been built and is used to control cavity field amplitude within ± 1% and relative phase within ± 1°. The fast digital processing is networked to the EPICS-based control system with an embedded processor (Blackfin). In this paper, the detailed description of the digital feedback RF control system will be described with the performance test results.

  16. The toughness of split graphs

    NARCIS (Netherlands)

    Woeginger, G.J.

    1998-01-01

    In this short note we argue that the toughness of split graphs can be computed in polynomial time. This solves an open problem from a recent paper by Kratsch et al. (Discrete Math. 150 (1996) 231–245).

  17. ISR split-field magnet

    CERN Multimedia

    CERN PhotoLab

    1975-01-01

    The experimental apparatus used at intersection 4 around the Split-Field Magnet by the CERN-Bologna Collaboration (experiment R406). The plastic scintillator telescopes are used for precise pulse-height and time-of-flight measurements.

  18. Triadic split-merge sampler

    Science.gov (United States)

    van Rossum, Anne C.; Lin, Hai Xiang; Dubbeldam, Johan; van der Herik, H. Jaap

    2018-04-01

    In machine vision typical heuristic methods to extract parameterized objects out of raw data points are the Hough transform and RANSAC. Bayesian models carry the promise to optimally extract such parameterized objects given a correct definition of the model and the type of noise at hand. A category of solvers for Bayesian models are Markov chain Monte Carlo methods. Naive implementations of MCMC methods suffer from slow convergence in machine vision due to the complexity of the parameter space. Towards this blocked Gibbs and split-merge samplers have been developed that assign multiple data points to clusters at once. In this paper we introduce a new split-merge sampler, the triadic split-merge sampler, that perform steps between two and three randomly chosen clusters. This has two advantages. First, it reduces the asymmetry between the split and merge steps. Second, it is able to propose a new cluster that is composed out of data points from two different clusters. Both advantages speed up convergence which we demonstrate on a line extraction problem. We show that the triadic split-merge sampler outperforms the conventional split-merge sampler. Although this new MCMC sampler is demonstrated in this machine vision context, its application extend to the very general domain of statistical inference.

  19. Measurements of the neutron yield from a coaxial gun plasma

    International Nuclear Information System (INIS)

    Zolototrubov, I.M.; Krasnikov, A.A.; Kurishchenko, A.M.; Novikov, Yu.M.; Poryatuj, V.S.; Tolstolutskij, A.G.

    1977-01-01

    Neutron yield from deuterium plasma produced by a pulse coaxial accelerator was measured. The maximum neutron yield with 5 kj stored in a condenser battery is 3x10 6 neutron/pulse. The basis of the method of measuring neutron yield from the plasma was through the induced activity. It was shown that application of even a small uniform longitudinal magnetic field (up to 1 kOe) on the accelerator decreases several times the neutron yield. It is also shown that a small amount of stored discharge energy can produce high-temperature plasma at the output of pulse coaxial accelerator in the absense of the direct magnetic field. It is supposed that the reason for the reduction of neutron yield level in the case of applying the magnetic field is decreasing plasma density because of increasing the bunch cross-section

  20. Coaxial gun parameters and X-ray emission

    International Nuclear Information System (INIS)

    Soliman, H.M.; El-Aragi, G.M.; Saudy, A.H.; Masoud, M.M.

    1994-01-01

    The paper presents the results of investigation with 3 kJ coaxial plasma gun, which operated with argon gas at pressure 0.8 torr. The coaxial plasma gun parameters are investigated by pick up coils, double electric probe, and x-ray probe. The mean electron temperature and density of the ejected plasma are 25 eV and 10 15 cm -3 respectively. The maximum kinetic pressure of the ejected plasma in the expansion chamber appears after 10 μs from the start of the discharge current. The energetic electrons is detected by an x-ray probe which showed a single pulse of electrons with energy ≅ 3 Kev. (orig.)

  1. Plasmonic coaxial Fabry-Pérot nanocavity color filter

    Science.gov (United States)

    Si, G. Y.; Leong, E. S. P.; Danner, A. J.; Teng, J. H.

    2010-08-01

    Plamonic coaxial structures have drawn considerable attetion recently because of their unique properties. They exhibit different mechanisms of extraordinary optical transmission observed from subwavelength holes and they can support localized Fabry-Pérot plasmon modes. In this work, we experimentally demonstrate color filters based on coaxial structures fabricated in optically thick metallic films. Using nanogaps with different apertures from 160 nm down to only 40 nm, we show varying color outputs when the annular aperture arrays are illuminated with a broadband light source. Effective color-filter function is demonstrated in the optical regime. Different color outputs are observed and optical spectra are measured. In such structures, it is the propagating mode playing an important role rather than the evanescent. Resonances depend strongly on ring apertures, enabling devices with tunability of output colors using simple geometry control.

  2. Non-coaxial superposition of vector vortex beams.

    Science.gov (United States)

    Aadhi, A; Vaity, Pravin; Chithrabhanu, P; Reddy, Salla Gangi; Prabakar, Shashi; Singh, R P

    2016-02-10

    Vector vortex beams are classified into four types depending upon spatial variation in their polarization vector. We have generated all four of these types of vector vortex beams by using a modified polarization Sagnac interferometer with a vortex lens. Further, we have studied the non-coaxial superposition of two vector vortex beams. It is observed that the superposition of two vector vortex beams with same polarization singularity leads to a beam with another kind of polarization singularity in their interaction region. The results may be of importance in ultrahigh security of the polarization-encrypted data that utilizes vector vortex beams and multiple optical trapping with non-coaxial superposition of vector vortex beams. We verified our experimental results with theory.

  3. A coaxial ring-sidearm power extraction design

    International Nuclear Information System (INIS)

    Ben-Menahem, S.; Yu, D.

    1996-01-01

    We report a successful klystron power extraction design, in which a TEM coaxial mode is transmitted into TE10 mode of a WR90 rectangular waveguide at 11.42 GHz, with very little TEM reflection and almost vanishing asymmetric (TEM → TE11, or monopole to dipole) reflectance. Our coupler consists of a ring (disk) around the coaxial waveguide, and a coax-WR90 sidearm junction. The methods used in the design are numerical simulation, performed on the MAFIA3 T3 time- domain module and on the High Frequency Structure Simulator, and analytical treatment to guide the numerical runs. The demerit parameters (dipole reflectance and TEM reflection) can be reduced as much as desired (to zero in principle), the only limitation being computer run time and memory. Results are accurate to a few percent

  4. COAXIAL TWO-CHANNEL DIELECTRIC WAKE FIELD ACCELERATOR

    Energy Technology Data Exchange (ETDEWEB)

    Hirshfield, Jay L. [Omega-P, Inc.

    2013-04-30

    Theory, computations, and experimental apparatus are presented that describe and are intended to confirm novel properties of a coaxial two-channel dielectric wake field accelerator. In this configuration, an annular drive beam in the outer coaxial channel excites multimode wakefields which, in the inner channel, can accelerate a test beam to an energy much higher than the energy of the drive beam. This high transformer ratio is the result of judicious choice of the dielectric structure parameters, and of the phase separation between drive bunches and test bunches. A structure with cm-scale wakefields has been build for tests at the Argonne Wakefield Accelerator Laboratory, and a structure with mm-scale wakefields has been built for tests at the SLAC FACET facility. Both tests await scheduling by the respective facilities.

  5. Risk factor analysis of pulmonary hemorrhage complicating CT-guided lung biopsy in coaxial and non-coaxial core biopsy techniques in 650 patients

    Energy Technology Data Exchange (ETDEWEB)

    Nour-Eldin, Nour-Eldin A., E-mail: nour410@hotmail.com [Institute for Diagnostic and Interventional Radiology, Johan Wolfgang Goethe – University Hospital, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Diagnostic and Interventional Radiology Department, Cairo University Hospital, Cairo (Egypt); Alsubhi, Mohammed [Institute for Diagnostic and Interventional Radiology, Johan Wolfgang Goethe – University Hospital, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Naguib, Nagy N. [Institute for Diagnostic and Interventional Radiology, Johan Wolfgang Goethe – University Hospital, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany); Diagnostic and Interventional Radiology Department, Alexandria University Hospital, Alexandria (Egypt); Lehnert, Thomas; Emam, Ahmed; Beeres, Martin; Bodelle, Boris; Koitka, Karen; Vogl, Thomas J.; Jacobi, Volkmar [Institute for Diagnostic and Interventional Radiology, Johan Wolfgang Goethe – University Hospital, Theodor-Stern-Kai 7, 60590 Frankfurt am Main (Germany)

    2014-10-15

    Purpose: To evaluate the risk factors involved in the development of pulmonary hemorrhage complicating CT-guided biopsy of pulmonary lesions in coaxial and non-coaxial techniques. Materials and methods: Retrospective study included CT-guided percutaneous lung biopsies in 650 consecutive patients (407 males, 243 females; mean age 54.6 years, SD: 5.2) from November 2008 to June 2013. Patients were classified according to lung biopsy technique in coaxial group (318 lesions) and non-coaxial group (332 lesions). Exclusion criteria for biopsy were: lesions <5 mm in diameter, uncorrectable coagulopathy, positive-pressure ventilation, severe respiratory compromise, pulmonary arterial hypertension or refusal of the procedure. Risk factors for pulmonary hemorrhage complicating lung biopsy were classified into: (a) patient's related risk factors, (b) lesion's related risk factors and (d) technical risk factors. Radiological assessments were performed by two radiologists in consensus. Mann–Whitney U test and Fisher's exact tests for statistical analysis. p values <0.05 were considered statistically significant. Results: Incidence of pulmonary hemorrhage was 19.6% (65/332) in non-coaxial group and 22.3% (71/318) in coaxial group. The difference in incidence between both groups was statistically insignificant (p = 0.27). Hemoptysis developed in 5.4% (18/332) and in 6.3% (20/318) in the non-coaxial and coaxial groups respectively. Traversing pulmonary vessels in the needle biopsy track was a significant risk factor of the development pulmonary hemorrhage (incidence: 55.4% (36/65, p = 0.0003) in the non-coaxial group and 57.7% (41/71, p = 0.0013) in coaxial group). Other significant risk factors included: lesions of less than 2 cm (p value of 0.01 and 0.02 in non-coaxial and coaxial groups respectively), basal and middle zonal lesions in comparison to upper zonal lung lesions (p = 0.002 and 0.03 in non-coaxial and coaxial groups respectively), increased lesion

  6. Risk factor analysis of pulmonary hemorrhage complicating CT-guided lung biopsy in coaxial and non-coaxial core biopsy techniques in 650 patients

    International Nuclear Information System (INIS)

    Nour-Eldin, Nour-Eldin A.; Alsubhi, Mohammed; Naguib, Nagy N.; Lehnert, Thomas; Emam, Ahmed; Beeres, Martin; Bodelle, Boris; Koitka, Karen; Vogl, Thomas J.; Jacobi, Volkmar

    2014-01-01

    Purpose: To evaluate the risk factors involved in the development of pulmonary hemorrhage complicating CT-guided biopsy of pulmonary lesions in coaxial and non-coaxial techniques. Materials and methods: Retrospective study included CT-guided percutaneous lung biopsies in 650 consecutive patients (407 males, 243 females; mean age 54.6 years, SD: 5.2) from November 2008 to June 2013. Patients were classified according to lung biopsy technique in coaxial group (318 lesions) and non-coaxial group (332 lesions). Exclusion criteria for biopsy were: lesions <5 mm in diameter, uncorrectable coagulopathy, positive-pressure ventilation, severe respiratory compromise, pulmonary arterial hypertension or refusal of the procedure. Risk factors for pulmonary hemorrhage complicating lung biopsy were classified into: (a) patient's related risk factors, (b) lesion's related risk factors and (d) technical risk factors. Radiological assessments were performed by two radiologists in consensus. Mann–Whitney U test and Fisher's exact tests for statistical analysis. p values <0.05 were considered statistically significant. Results: Incidence of pulmonary hemorrhage was 19.6% (65/332) in non-coaxial group and 22.3% (71/318) in coaxial group. The difference in incidence between both groups was statistically insignificant (p = 0.27). Hemoptysis developed in 5.4% (18/332) and in 6.3% (20/318) in the non-coaxial and coaxial groups respectively. Traversing pulmonary vessels in the needle biopsy track was a significant risk factor of the development pulmonary hemorrhage (incidence: 55.4% (36/65, p = 0.0003) in the non-coaxial group and 57.7% (41/71, p = 0.0013) in coaxial group). Other significant risk factors included: lesions of less than 2 cm (p value of 0.01 and 0.02 in non-coaxial and coaxial groups respectively), basal and middle zonal lesions in comparison to upper zonal lung lesions (p = 0.002 and 0.03 in non-coaxial and coaxial groups respectively), increased lesion

  7. Degradation of aqueous phenol solutions by coaxial DBD reactor

    Science.gov (United States)

    Dojcinovic, B. P.; Manojlovic, D.; Roglic, G. M.; Obradovic, B. M.; Kuraica, M. M.; Puric, J.

    2008-07-01

    Solutions of 2-chlorophenol, 4-chlorophenol and 2,6-dichlorophenol in bidistilled and water from the river Danube were treated in plasma reactor. In this reactor, based on coaxial dielectric barrier discharge at atmospheric pressure, plasma is formed over a thin layer of treated water. After one pass through the reactor, starting chlorophenols concentration of 20 mg/l was diminished up to 95 %. Kinetics of the chlorophenols degradation was monitored by High Pressure Liquid Chromatography method (HPLC).

  8. rf coaxial couplers for high-intensity linear accelerators

    International Nuclear Information System (INIS)

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

    1980-02-01

    Two rf coaxial couplers that are particularly suitable for intertank connection of the disk-and-washer accelerating structure for use in high-intensity linear accelerators have been developed. These devices have very high coupling to the accelerating structure and very low rf power loss at the operating frequency, and they can be designed for any relative particle velocity β > 0.4. Focusing and monitoring devices can be located inside these couplers

  9. X-ray Radiography Measurements of Shear Coaxial Rocket Injectors

    Science.gov (United States)

    2013-05-07

    Shear coaxial jets can be found in a number of combustion devices – Turbofan engine exhaust , air blast furnaces, and liquid rocket engines ...water and gaseous nitro-gen as propellant simulants at atmospheric backpressure , the effect of momentum flux ratio and mass flux ratio, are...the effect of momentum flux ratio, mass flux ratio and post thickness on the liquid mass distribution – Use quantitative centerline profiles to

  10. Plasma gun with coaxial powder feed and adjustable cathode

    Science.gov (United States)

    Zaplatynsky, Isidor (Inventor)

    1991-01-01

    An improved plasma gun coaxially injects particles of ceramic materials having high melting temperatures into the central portion of a plasma jet. This results in a more uniform and higher temperature and velocity distribution of the sprayed particles. The position of the cathode is adjustable to facilitate optimization of the performance of the gun wherein grains of the ceramic material are melted at lower power input levels.

  11. Zero cross over timing with coaxial Ge(Li) detectors

    International Nuclear Information System (INIS)

    El-Ibiary, M.Y.

    1979-07-01

    The performance of zero cross over timing systems of the constant fraction or amplitude rise time compensated type using coaxial Ge(Li) detectors is analyzed with special attention to conditions that compromise their energy-independence advantage. The outcome is verified against existing experimental results, and the parameters that lead to minimum disperson, as well as the value of the dispersion to be expected, are given by a series of charts

  12. Particle beam dynamics in a magnetically insulated coaxial diode

    International Nuclear Information System (INIS)

    Korenev, V.G.; Magda, I.I.; Sinitsin, V.G.

    2015-01-01

    The dynamics of charged particle beams emitted from a cathode into a smooth coaxial diode with magnetic insulation is studied with the aid of 3-D PIC simulation. The processes controlling space charge formation and its evolution in the diode are modeled for geometries typical of high-voltage millimeter wave magnetrons that are characterized by very high values of emission currents, hence high space charge densities.

  13. Radiation from a Slot System in the Coaxial Line Shield

    Science.gov (United States)

    Katrich, V. A.; Lyashchenko, V. A.; Medvedev, N. V.

    2012-06-01

    The problem of electromagnetic wave excitation, scattering and radiation by the system of transverse slots, cut in the outer conductor of an infinite coaxial line, is solved by the magnetomotive forces method. The radiation and reflection coefficients of the circular and arc slot systems are investigated in dependence on slot sizes and feeder parameters. The processes of radiation into lossy material media are studied. The researches have been carried out with the interconnection between slots of internal and external regions considered.

  14. Acoustically Forced Coaxial Hydrogen / Liquid Oxygen Jet Flames

    Science.gov (United States)

    2016-05-15

    Conference Paper 3. DATES COVERED (From - To) 18 Mar 2016 – 15 May 2016 4. TITLE AND SUBTITLE Acoustically Forced Coaxial Hydrogen / Liquid Oxygen Jet...perform, display, or disclose the work. 13. SUPPLEMENTARY NOTES For presentation at 28th Annual Conference on Liquid Atomization and Spray Systems...serious problems in the development of liquid rocket engines. In order to understand and predict them, it is necessary to understand how representative

  15. Miniature Coaxial Plasma injector Diagnostics by Beam Plasma Interaction

    International Nuclear Information System (INIS)

    El-Tayeb, H.; El-Gamal, H.

    2003-01-01

    A miniature coaxial gun has been used to study the interaction between plasma beam and low density plasma formed in glow discharge. The peak discharge current flow between the coaxial electrodes was 5.25 kA as a single pulse with pulse width of 60 mu. Investigations are carried out with argon gas at pressure 0.4 Torr. The plasma stream ejected from the coaxial discharge propagates in the neutral argon atoms with mean velocity of 1.2x10 5 cm/s. The plasma stream temperature and density were 4.2 eV and 2.4x10 13 cm -3 respectively. An argon negative glow has been used as base plasma where its electron temperature and density were 2.2 eV and 6.2x10 7 cm -3 respectively. When the plasma stream propagates through the negative glow discharge region its velocity decreased to 8.8 x 10 4 cm/s and also the plasma electron temperature decreased to 3.1 eV, while the stream density remained the same. An excited wave appeared on the electric probe having frequency equal to the plasma frequency of the plasma under consideration. Simulation of the problem showed that this method could be applied for plasma diagnostics within the region of investigation. Those further studies for high temperature, dense, and magnetized plasma will be considered

  16. A Penning-assisted subkilovolt coaxial plasma source

    International Nuclear Information System (INIS)

    Wang Zhehui; Beinke, Paul D.; Barnes, Cris W.; Martin, Michael W.; Mignardot, Edward; Wurden, Glen A.; Hsu, Scott C.; Intrator, Thomas P.; Munson, Carter P.

    2005-01-01

    A Penning-assisted 20 MW coaxial plasma source (plasma gun), which can achieve breakdown at sub-kV voltages, is described. The minimum breakdown voltage is about 400 V, significantly lower than previously reported values of 1-5 kV. The Penning region for electrons is created using a permanent magnet assembly, which is mounted to the inside of the cathode of the coaxial plasma source. A theoretical model for the breakdown is given. A 900 V 0.5 F capacitor bank supplies energy for gas breakdown and plasma sustainment from 4 to 6 ms duration. Typical peak gun current is about 100 kA and gun voltage between anode and cathode after breakdown is about 200 V. A circuit model is used to understand the current-voltage characteristics of the coaxial gun plasma. Energy deposited into the plasma accounts for about 60% of the total capacitor bank energy. This plasma source is uniquely suitable for studying multi-MW multi-ms plasmas with sub-MJ capacitor bank energy

  17. Flexible supercapacitor yarns with coaxial carbon nanotube network electrodes

    International Nuclear Information System (INIS)

    Smithyman, Jesse; Liang, Richard

    2014-01-01

    Graphical abstract: - Highlights: • Fabricated flexible yarn supercapacitor with coaxial electrodes. • Use of multifunctional carbon nanotube network electrodes eliminates inactive components and enables high energy/power density. • Robust structure maintains >95% of energy/power while under deformation. - Abstract: Flexible supercapacitors with a yarn-like geometry were fabricated with coaxially arranged electrodes. Carbon nanotube (CNT) network electrodes enabled the integration of the electronic conductor and active material of each electrode into a single component. CNT yarns were employed as the inner electrode to provide the supporting structure of the device. These part integration strategies eliminated the need for inactive material, which resulted in device volumetric energy and power densities among the highest reported for flexible carbon-based EDLCs. In addition, the coaxial yarn cell design provided a robust structure able to undergo flexural deformation with minimal impact on the energy storage performance. Greater than 95% of the energy density and 99% of the power density were retained when wound around an 11 cm diameter cylinder. The electrochemical properties were characterized at stages throughout the fabrication process to provide insights and potential directions for further development of these novel cell designs

  18. Fabrication and Characterisation of Flexible Coaxial Thin Thread Supercapacitors

    Directory of Open Access Journals (Sweden)

    Fulian Qiu

    2014-08-01

    Full Text Available Flexible coaxial thin thread supercapacitors were fabricated semi-automatically using a dip coating method. A typical coaxial thin thread supercapacitor of a length of 70 cm demonstrated a specific length capacitance of 0.3 mF cm-1 (11.2 mF cm-2 and 2.18 F cm-3 at 5 mV s-1, the device exhibited good electrochemical performance with a high volume energy density of 0.22 mWh cm-3 at a power density of 22 mW cm-3. Thread supercapacitors were assembled in series and parallel combinations, the accepted models for series and parallel circuit combinations were obeyed for two coaxial thread supercapacitors. The thread shows high flexibility and uniformity of specific length capacitance, one integrated with a commercial solar cell could be charged and power a LED. The process is simple, robust and easy to scale up to make unlimited length thread supercapacitors for numerous miniaturized and flexible electronic applications.

  19. Spectral diagnostic of plasma in the coaxial gun

    International Nuclear Information System (INIS)

    Bacilek, J.; Hruska, J.; Kubes, P.

    1975-01-01

    Plasma ejected from a coaxial plasma gun was investigated spectroscopically. The coaxial gun consisted of two copper coaxial electrodes 57 and 100 mm in diameter, the length of the central electrode being 67 mm. The gun was fed by a 11 μF capacitor bank of 16 kV operating voltage. Hydrogen, helium and air were used as working gases. The emission spectra were recorded with spectrograph ISP-51 and with a monochromator-photomultiplier system. The plasma density reached its maximum of 4x10 15 cm -3 with the ejecting voltage applied some 20 to 30 μs after the gas injection. At this moment also the spectral lines of electrode material were most intensive. The electron temperature calculated from the presence of spectral lines of OII, CII and NII was about 2 eV. The velocity of fast hydrogen ions was 4x10 7 cmsec -1 calculated from the Hsub(β) line. (J.U.)

  20. Particle-like structure of coaxial Lie algebras

    Science.gov (United States)

    Vinogradov, A. M.

    2018-01-01

    This paper is a natural continuation of Vinogradov [J. Math. Phys. 58, 071703 (2017)] where we proved that any Lie algebra over an algebraically closed field or over R can be assembled in a number of steps from two elementary constituents, called dyons and triadons. Here we consider the problems of the construction and classification of those Lie algebras which can be assembled in one step from base dyons and triadons, called coaxial Lie algebras. The base dyons and triadons are Lie algebra structures that have only one non-trivial structure constant in a given basis, while coaxial Lie algebras are linear combinations of pairwise compatible base dyons and triadons. We describe the maximal families of pairwise compatible base dyons and triadons called clusters, and, as a consequence, we give a complete description of the coaxial Lie algebras. The remarkable fact is that dyons and triadons in clusters are self-organised in structural groups which are surrounded by casings and linked by connectives. We discuss generalisations and applications to the theory of deformations of Lie algebras.

  1. Construction and building of a compact RFQ spiral structure for the stopping of highly charged heavy ion beams for the HITRAP project of the GSI

    International Nuclear Information System (INIS)

    Hofmann, B.

    2007-01-01

    For experiments of the atomic-physics group of the GSI in Darmstadt an ion stopper is built, which will make low-energetic, extremely highly charged ions available. The plannings for the so-called HITRAP (highly charged ion's trap) began at the beginning of the ninetieth. With this facility highly-charged heavy ions shall be stopped in two stages to very low, thermal velocities, and be available for highly precise mass spectroscopy, measurements of the g factor of the bound electron of hydrogen-like ions, and other atomic-physics experiments. This decelerator facility shall first be built in the reinjection channel behind the ESR with the possibility, to apply all components later in teh extension of the GSI in the framework of the FAIR project in the facility for low-energetic antiprotons and ions to be newly built. the present thesis treats the development and the building of an integrated RFQ debuncher stopping accelerator, which represents a part of the HITRAP stopping structures. By this the ion beam is stopped from the IH stopping accelerator with an energy of 500 keV/u to 5 keV/u. By the integrated spiral buncher the beam can be fitted in energy and energy deviation to the subsequent cooler trap. In this thesis the foundations of the particle dynamics in a RFQ accelerator for the stopping of particle beams were worked out and realized, the particle-dynamics calculations necessary for the lay-out of such a structure performed with RFQSim, suitable RF structures with the simulation program Microwave Studio developed and studied, as well as the thermal load of the structures studied with the finite-element code ALGOR. A further, central topic of this thesis is the building and the tuning of the RFQ structure in order to reach a homogeneous as possible field distribution along the electrodes. Measurements of the fields in the RFQ were performed with a disturbing condenser, at the debuncher with a disturbing body. After successfully performed vacuum tests at the

  2. Splitting: The Development of a Measure.

    Science.gov (United States)

    Gerson, Mary-Joan

    1984-01-01

    Described the development of a scale that measures splitting as a psychological structure. The construct validity of the splitting scale is suggested by the positive relationship between splitting scores and a diagnostic measure of the narcissistic personality disorder, as well as a negative relationship between splitting scores and levels of…

  3. MAXILAC as a high current UNILAC injector

    International Nuclear Information System (INIS)

    Ungrin, J.; Klabunde, J.

    1984-08-01

    MAXILAC, an RFQ of split coaxial resonator design, will deliver heavy ion currents in the 20-30 mA range with energies in the 100-150 keV/u range. One proposed method of coupling this RFQ to UNILAC is to divide the first tank of the Wideroee section into two segments and to inject the MAXILAC beam for acceleration starting with the second segment. This injection scheme has been investigated in detail with the beam dynamics codes MIKRO, PARMT and PARMI. Other injection schemes are also considered. (orig.)

  4. Analytic study of transverse shunt resistance and even-odd mode coupling of a rod type RFQ

    International Nuclear Information System (INIS)

    Koscielniak, S.

    1994-06-01

    To minimize the ohmic power losses, it is necessary to maximize the transverse shunt resistance, R shunt . The cell of a rod-type RFQ is modelled by a parallel two-rod transmission line supported above a parallel ground conductor by two legs. Due to coupling between neighboring supports, the loading impedance is modified depending on the leg spacing. The shunt resistance is improved by reducing the cell length and increasing the leg spacing, and maximized when the legs are equally spaced. However, this is also the condition for strong excitation of the unwanted 'even-mode' in which a potential difference exists between the ends of the rods mid-plane and the grounding conductor or tank, Once the legs of the support are longitudinally separated, some even-mode excitation of the structure is inevitable because some current must be injected into the ground conductor; the even-mode excitation rises as leg separation increases. Further, when the desired odd-mode voltage is symmetric about the cell centre, the even-mode voltage is anti-symmetric This paper is a very much abridged version of two internal design notes[3], [4]. (author). 4 refs.,1 fig

  5. Split NMSSM with electroweak baryogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Demidov, S.V.; Gorbunov, D.S. [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary prospect 7a, Moscow 117312 (Russian Federation); Moscow Institute of Physics and Technology,Institutsky per. 9, Dolgoprudny 141700 (Russian Federation); Kirpichnikov, D.V. [Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary prospect 7a, Moscow 117312 (Russian Federation)

    2016-11-24

    In light of the Higgs boson discovery and other results of the LHC we reconsider generation of the baryon asymmetry in the split Supersymmetry model with an additional singlet superfield in the Higgs sector (non-minimal split SUSY). We find that successful baryogenesis during the first order electroweak phase transition is possible within a phenomenologically viable part of the model parameter space. We discuss several phenomenological consequences of this scenario, namely, predictions for the electric dipole moments of electron and neutron and collider signatures of light charginos and neutralinos.

  6. Split ring containment attachment device

    International Nuclear Information System (INIS)

    Sammel, A.G.

    1996-01-01

    A containment attachment device is described for operatively connecting a glovebag to plastic sheeting covering hazardous material. The device includes an inner split ring member connected on one end to a middle ring member wherein the free end of the split ring member is inserted through a slit in the plastic sheeting to captively engage a generally circular portion of the plastic sheeting. A collar potion having an outer ring portion is provided with fastening means for securing the device together wherein the glovebag is operatively connected to the collar portion. 5 figs

  7. Splitting strings on integrable backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Vicedo, Benoit

    2011-05-15

    We use integrability to construct the general classical splitting string solution on R x S{sup 3}. Namely, given any incoming string solution satisfying a necessary self-intersection property at some given instant in time, we use the integrability of the worldsheet {sigma}-model to construct the pair of outgoing strings resulting from a split. The solution for each outgoing string is expressed recursively through a sequence of dressing transformations, the parameters of which are determined by the solutions to Birkhoff factorization problems in an appropriate real form of the loop group of SL{sub 2}(C). (orig.)

  8. Mass splitting induced by gravitation

    International Nuclear Information System (INIS)

    Maia, M.D.

    1982-08-01

    The exact combination of internal and geometrical symmetries and the associated mass splitting problem is discussed. A 10-parameter geometrical symmetry is defined in a curved space-time in such a way that it is a combination of de Sitter groups. In the flat limit it reproduces the Poincare-group and its Lie algebra has a nilpotent action on the combined symmetry only in that limit. An explicit mass splitting expression is derived and an estimation of the order of magnitude for spin-zero mesons is made. (author)

  9. Split supersymmetry in brane models

    Indian Academy of Sciences (India)

    Type-I string theory in the presence of internal magnetic fields provides a concrete realization of split ... quantum picture of the Universe. It was then ... where the integers m, n correspond to the respective magnetic and electric charges; m is the ...

  10. VBSCan Split 2017 Workshop Summary

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Christoph Falk; et al.

    2018-01-12

    This document summarises the talks and discussions happened during the VBSCan Split17 workshop, the first general meeting of the VBSCan COST Action network. This collaboration is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

  11. Stability of split Stirling refrigerators

    NARCIS (Netherlands)

    Waele, de A.T.A.M.; Liang, W.

    2009-01-01

    In many thermal systems spontaneous mechanical oscillations are generated under the influence of large temperature gradients. Well-known examples are Taconis oscillations in liquid-helium cryostats and oscillations in thermoacoustic systems. In split Stirling refrigerators the compressor and the

  12. Interaction of plasma with magnetic fields in coaxial discharge

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, H.M.; Masoud, M.M. (National Research Centre, Cairo (Egypt))

    1991-01-01

    Previous experiments have shown that, in normal mode of focus operation (67 KJ-20 KV) i.e. without external magnetic fields, the focus exhibits instability growths as revealed by the time integrated X-ray pinhole photographs. A magnetic field which is trapped ahead of the current sheath will reduce the high ejection rate of plasma which occurs during the (r,z) collapse stage. This reduction should lead to a more uniform plasma of larger dimension. If an externally excited axial magnetic field of (10[sup 2]-10[sup 3] G) is introduced at the end of the central electrode of coaxial discharge with 45 [mu]f capacitor bank, U[sub ch]=13-17 KV, peak current [approx]0.5 MA, the decay rate of the current sheath is slowed down and the minimum radius of the column remains large enough. Experiment investigation of the X-ray emission in axial direction from a (12 KJ/20 KV, 480 KA), Mather type focus, showed that the X-ray intensity changes drastically, by superimposing an axial magnetic field of 55 G on the focus. By introducing an external axial magnetic field of intensity 2.4 KG along the coaxial electrodes, this magnetic field has a radial component at distances approach to muzzle of coaxial discharge with charging voltage 10 KV and peak discharge current 100 KA. Presence of these magnetic fields, will cause an increase in intensity of soft X-ray emission. The main purpose of this work is to study the interactions of axial and transverse magnetic fields with plasma sheath during the axial interelectrode propagation, and its effects on the X-ray emission from plasma focus. (author) 4 refs., 7 figs.

  13. Interaction of plasma with magnetic fields in coaxial discharge

    International Nuclear Information System (INIS)

    Soliman, H.M.; Masoud, M.M.

    1991-01-01

    Previous experiments have shown that, in normal mode of focus operation (67 KJ-20 KV) i.e. without external magnetic fields, the focus exhibits instability growths as revealed by the time integrated X-ray pinhole photographs. A magnetic field which is trapped ahead of the current sheath will reduce the high ejection rate of plasma which occurs during the (r,z) collapse stage. This reduction should lead to a more uniform plasma of larger dimension. If an externally excited axial magnetic field of (10 2 -10 3 G) is introduced at the end of the central electrode of coaxial discharge with 45 μf capacitor bank, U ch =13-17 KV, peak current ∼0.5 MA, the decay rate of the current sheath is slowed down and the minimum radius of the column remains large enough. Experiment investigation of the X-ray emission in axial direction from a (12 KJ/20 KV, 480 KA), Mather type focus, showed that the X-ray intensity changes drastically, by superimposing an axial magnetic field of 55 G on the focus. By introducing an external axial magnetic field of intensity 2.4 KG along the coaxial electrodes, this magnetic field has a radial component at distances approach to muzzle of coaxial discharge with charging voltage 10 KV and peak discharge current 100 KA. Presence of these magnetic fields, will cause an increase in intensity of soft X-ray emission. The main purpose of this work is to study the interactions of axial and transverse magnetic fields with plasma sheath during the axial interelectrode propagation, and its effects on the X-ray emission from plasma focus. (author) 4 refs., 7 figs

  14. Study of powder formation in reactive coaxial jets

    International Nuclear Information System (INIS)

    Ablitzer, C.

    1999-01-01

    One step of the conversion of gaseous UF 6 to solid UO 2 by dry route is the formation of particles of UO 2 F 2 in a triple coaxial jet UF 6 /N 2 /H 2 O. The characteristics of resulting powder have an influence on the properties of final particles of UO 2 , and then on the quality of pellets of nuclear fuel. So a good control of this step of the process is of interest. This study deals with an experimental investigation and a modelling of the influence of various parameters on particles obtained by reaction in a turbulent coaxial jet. For example, the influence of absolute and relative velocities of gases on particle size distributions has been investigated. Two kinds of experimental studies have been undertaken. First, the development of mixing layers in the near field of the jet has been evaluated with temperature measurements. Then, particle size distributions have been measured with a turbidimetric sensor, for particles obtained by hydrolysis of gaseous metallic chlorides (SnCl 4 , TiCl 4 ) in double and triple coaxial jets. A model has been proposed for mixing of gases and growth of particles. It takes into account the development of mixing layers, meso-mixing, micro-mixing and growth of particles through agglomeration. The influence of operating parameters, especially velocities, on experimental results appear to be different for TiCl 4 /H 2 O jets and SnCl 4 /H 2 O jets. In fact, a comparison of theoretical and experimental results shows that particles obtained by hydrolysis of TiCl 4 seem to grow mainly through agglomeration whereas another growth phenomenon may be involved for particles obtained by hydrolysis of SnCl 4 . (author)

  15. Study of fuel powder formation in reactive coaxial jets

    International Nuclear Information System (INIS)

    Ablitzer, C.

    1999-01-01

    One step of the conversion of gaseous UF 6 to solid UO 2 by dry route is the formation of particles of UO 2 F 2 in a triple coaxial jet UF 6 /N 2 /H 2 O. The characteristics of resulting powder have an influence on the properties of final particles of UO 2 , and then on the quality of pellets of nuclear fuel. So a good control of this step of the process is of interest. This study deals with an experimental investigation and modelling of the influence of various parameters on particles obtained by reaction in a turbulent coaxial jet. For example, the influence of absolute and relative velocities of gases on particle size distributions has been investigated. Two kinds of experimental studies have been undertaken. First, the development of mixing layers in the near field of the jet has been evaluated with temperature measurements. Then, particle size distributions have been measured with e turbidimetric sensor, for particles obtained by hydrolysis of gaseous metallic chlorides (SnCl 4 , TiCl 4 ) in double and triple coaxial jets. A model has been proposed for mixing of gases and growth of particles. It takes into account the development of mixing layers, meso-mixing, micro-mixing and growth of particles through agglomeration. The influence of operating parameters, especially velocities, on experimental results appear to be different for TiCl 4 /H 2 O jets and SnCl 4 /H 2 O jets. In fact, a comparison of theoretical and experimental results shows that particles obtained by hydrolysis of TiCl 4 seem to grow mainly through agglomeration whereas another growth phenomenon may be involved for particles obtained by hydrolysis of SnCl 4 . (authors)

  16. Analytical solution for a coaxial plasma gun: Weak coupling limit

    International Nuclear Information System (INIS)

    Dietz, D.

    1987-01-01

    The analytical solution of the system of coupled ODE's which describes the time evolution of an ideal (i.e., zero resistance) coaxial plasma gun operating in the snowplow mode is obtained in the weak coupling limit, i.e, when the gun is fully influenced by the driving (RLC) circuit in which it resides but the circuit is negligibly influenced by the gun. Criteria for the validity of this limit are derived and numerical examples are presented. Although others have obtained approximate, asymptotic and numerical solutions of the equations, the present analytical results seem not to have appeared previously in the literature

  17. Plasma-filled diode based on the coaxial gun

    Science.gov (United States)

    Zherlitsyn, A. A.; Kovalchuk, B. M.; Pedin, N. N.

    2012-10-01

    The paper presents the results of studies of a coaxial gun for a plasma-filled electron diode. Effects of the discharge channel diameter and gun current on characteristics of the plasma and pulse generated in the diode were investigated. The electron beam with maximum energy of ≥1 MeV at the current of ≈100 kA was obtained in the experiments with a plasma-filled diode. The energy of ≈5 kJ with the peak power of ≥100 GW dissipated in the diode.

  18. Plasma-filled diode based on the coaxial gun.

    Science.gov (United States)

    Zherlitsyn, A A; Kovalchuk, B M; Pedin, N N

    2012-10-01

    The paper presents the results of studies of a coaxial gun for a plasma-filled electron diode. Effects of the discharge channel diameter and gun current on characteristics of the plasma and pulse generated in the diode were investigated. The electron beam with maximum energy of ≥1 MeV at the current of ≈100 kA was obtained in the experiments with a plasma-filled diode. The energy of ≈5 kJ with the peak power of ≥100 GW dissipated in the diode.

  19. Space charge effects for multipactor in coaxial lines

    Energy Technology Data Exchange (ETDEWEB)

    Sorolla, E., E-mail: eden.sorolla@xlim.fr [XLIM, UMR 7252, Université de Limoges/CNRS, 123 Av. Albert Thomas, 87060 Limoges (France); Sounas, A.; Mattes, M. [Laboratoire d' Électromagnétisme et d' Acoustique (LEMA), École Polytechnique Fédérale de Lausanne, Station 11, CH-1015 Lausanne (Switzerland)

    2015-03-15

    Multipactor is a hazardous vacuum discharge produced by secondary electron emission within microwave devices of particle accelerators and telecommunication satellites. This work analyzes the dynamics of the multipactor discharge within a coaxial line for the mono-energetic electron emission model taking into account the space charge effects. The steady-state is predicted by the proposed model and an analytical expression for the maximum number of electrons released by the discharge presented. This could help to link simulations to experiments and define a multipactor onset criterion.

  20. Simulation of non-linear coaxial line using ferrite beads

    International Nuclear Information System (INIS)

    Furuya, S.; Matsumoto, H.; Tachi, K.; Takano, S.; Irisawa, J.

    2002-01-01

    A ferrite sharpener is a non-linear coaxial line using ferrite beads, which produces high-voltage, high-dV/dt pulses. We have been examining the characteristics of ferrite sharpeners experimentally, varying various parameters. Also we have made the simulation of the ferrite sharpener and compared the predictions with the experimental results in detail to analyze the characteristics of the sharpener. In this report, calculating the magnetization M of the ferrite bead, we divide the bead into n sections radially instead of adopting M at the average radius in the previous report. (author)

  1. Plasma-filled diode based on the coaxial gun

    Energy Technology Data Exchange (ETDEWEB)

    Zherlitsyn, A. A.; Kovalchuk, B. M.; Pedin, N. N. [Institute of High Current Electronics, 2/3 Academichesky Avenue, 634055 Tomsk (Russian Federation)

    2012-10-15

    The paper presents the results of studies of a coaxial gun for a plasma-filled electron diode. Effects of the discharge channel diameter and gun current on characteristics of the plasma and pulse generated in the diode were investigated. The electron beam with maximum energy of {>=}1 MeV at the current of Almost-Equal-To 100 kA was obtained in the experiments with a plasma-filled diode. The energy of Almost-Equal-To 5 kJ with the peak power of {>=}100 GW dissipated in the diode.

  2. Space charge effects for multipactor in coaxial lines

    International Nuclear Information System (INIS)

    Sorolla, E.; Sounas, A.; Mattes, M.

    2015-01-01

    Multipactor is a hazardous vacuum discharge produced by secondary electron emission within microwave devices of particle accelerators and telecommunication satellites. This work analyzes the dynamics of the multipactor discharge within a coaxial line for the mono-energetic electron emission model taking into account the space charge effects. The steady-state is predicted by the proposed model and an analytical expression for the maximum number of electrons released by the discharge presented. This could help to link simulations to experiments and define a multipactor onset criterion

  3. A Coaxial Vortex Ring Model for Vortex Breakdown

    OpenAIRE

    Blackmore, Denis; Brons, Morten; Goullet, Arnaud

    2008-01-01

    A simple - yet plausible - model for B-type vortex breakdown flows is postulated; one that is based on the immersion of a pair of slender coaxial vortex rings in a swirling flow of an ideal fluid rotating around the axis of symmetry of the rings. It is shown that this model exhibits in the advection of passive fluid particles (kinematics) just about all of the characteristics that have been observed in what is now a substantial body of published research on the phenomenon of vortex breakdown....

  4. Plasma-filled diode based on the coaxial gun

    International Nuclear Information System (INIS)

    Zherlitsyn, A. A.; Kovalchuk, B. M.; Pedin, N. N.

    2012-01-01

    The paper presents the results of studies of a coaxial gun for a plasma-filled electron diode. Effects of the discharge channel diameter and gun current on characteristics of the plasma and pulse generated in the diode were investigated. The electron beam with maximum energy of ≥1 MeV at the current of ≈100 kA was obtained in the experiments with a plasma-filled diode. The energy of ≈5 kJ with the peak power of ≥100 GW dissipated in the diode.

  5. Spatial properties of coaxial superposition of two coherent Gaussian beams

    CSIR Research Space (South Africa)

    Boubaha, B

    2013-08-01

    Full Text Available that of the first focal point owing to its larger diameter, and subsequently decreases as K increases. 3. Interferometric Beam Shaping An interesting feature of the CGB is when the param- eter K is reduced, one observes that the number of rings shown in Fig. 1... for K . It is remarkable to notice that the beam shaping properties displayed in Fig. 5 are obtained from the interference of two coherent GBs, which are coaxially superposed by resorting to a two-wave interferom- eter or by generating the modulating...

  6. Theory and Circuit Model for Lossy Coaxial Transmission Line

    Energy Technology Data Exchange (ETDEWEB)

    Genoni, T. C.; Anderson, C. N.; Clark, R. E.; Gansz-Torres, J.; Rose, D. V.; Welch, Dale Robert

    2017-04-01

    The theory of signal propagation in lossy coaxial transmission lines is revisited and new approximate analytic formulas for the line impedance and attenuation are derived. The accuracy of these formulas from DC to 100 GHz is demonstrated by comparison to numerical solutions of the exact field equations. Based on this analysis, a new circuit model is described which accurately reproduces the line response over the entire frequency range. Circuit model calculations are in excellent agreement with the numerical and analytic results, and with finite-difference-time-domain simulations which resolve the skindepths of the conducting walls.

  7. Vortex Ring Interaction With a Coaxially Aligned Cylinderical Rod

    Science.gov (United States)

    Arakeri, Jaywant H.; Rajmanoharan, P.; Koochesfahani, Manoochehr

    1998-11-01

    We present results of experiments of a fully developed vortex ring interacting with a cylinderical rod, having a rounded nose, placed coaxially in line with the motion of the ring. The pressure field of the translating ring causes unsteady boundary layer separation and results in the formation of one or more ( secondary ) vortex rings, that subsequently interact. The nature and strength of the interaction depends on the ratio of the cylinder diameter to the ring diameter. For the larger diameter cylinders the vortex ring travels a few ring diameters before it breaks up. For the smaller diameter cylinders the vortex ring speed decreases slowly and, simultaneously, its diameter increases.

  8. Noninductive Current Generation in NSTX using Coaxial Helicity Injection

    International Nuclear Information System (INIS)

    Raman, R.; Jarboe, T.R.; Mueller, D.; Schaffer, M.J.; Maqueda, R.; Nelson, B.A.; Sabbagh, S.; Bell, M.; Ewig, R.; Fredrickson, E.; Gates, D.; Hosea, J.; Jardin, S.; Ji, H.; Kaita, R.; Kaye, S.M.; Kugel, H.; Lao, L.; Maingi, R.; Menard, J.; Ono, M.; Orvis, D.; Paul, S.; Peng, M.; Skinner, C.H.; Wilgen, J.B.; Zweben, S.

    2001-01-01

    Coaxial Helicity Injection (CHI) on the National Spherical Torus Experiment (NSTX) has produced 240 kA of toroidal current without the use of the central solenoid. Values of the current multiplication ratio (CHI produced toroidal current/injector current) up to 10 were obtained, in agreement with predictions. The discharges which lasted for up to 200 ms, limited only by the programmed waveform, are more than an order of magnitude longer in duration that any CHI discharges previously produced in a Spheromak or a Spherical Torus (ST)

  9. Ionization effects and linear stability in a coaxial plasma device

    Science.gov (United States)

    Kurt, Erol; Kurt, Hilal; Bayhan, Ulku

    2009-03-01

    A 2-D computer simulation of a coaxial plasma device depending on the conservation equations of electrons, ions and excited atoms together with the Poisson equation for a plasma gun is carried out. Some characteristics of the plasma focus device (PF) such as critical wave numbers a c and voltages U c in the cases of various pressures Pare estimated in order to satisfy the necessary conditions of traveling particle densities ( i.e. plasma patterns) via a linear analysis. Oscillatory solutions are characterized by a nonzero imaginary part of the growth rate Im ( σ) for all cases. The model also predicts the minimal voltage ranges of the system for certain pressure intervals.

  10. Spoof surface plasmons propagating along a periodically corrugated coaxial waveguide

    International Nuclear Information System (INIS)

    Talebi, Nahid; Shahabadi, Mahmoud

    2010-01-01

    Using the rigorous mode-matching technique, we have investigated a periodically corrugated perfectly conducting coaxial waveguide for the possibility of propagation of localized spoof surface plasmons. To verify our results, the computed band diagram of the structure has been compared with the one obtained using the body-of-revolution finite-difference time-domain method. The obtained spoof surface plasmon modes have been shown to be highly localized and slowly propagating. Variations of the obtained modal frequencies and mode profiles as a function of the depth and width of the grooves have also been investigated.

  11. Spoof surface plasmons propagating along a periodically corrugated coaxial waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Talebi, Nahid; Shahabadi, Mahmoud, E-mail: n.talebi@ece.ut.ac.i [Photonics Research Laboratory, Center of Excellence for Applied Electromagnetic Systems, School of Electrical and Computer Engineering, University of Tehran, North Kargar Ave., Tehran (Iran, Islamic Republic of)

    2010-04-07

    Using the rigorous mode-matching technique, we have investigated a periodically corrugated perfectly conducting coaxial waveguide for the possibility of propagation of localized spoof surface plasmons. To verify our results, the computed band diagram of the structure has been compared with the one obtained using the body-of-revolution finite-difference time-domain method. The obtained spoof surface plasmon modes have been shown to be highly localized and slowly propagating. Variations of the obtained modal frequencies and mode profiles as a function of the depth and width of the grooves have also been investigated.

  12. Coaxial waveguide mode reconstruction and analysis with THz digital holography.

    Science.gov (United States)

    Wang, Xinke; Xiong, Wei; Sun, Wenfeng; Zhang, Yan

    2012-03-26

    Terahertz (THz) digital holography is employed to investigate the properties of waveguides. By using a THz digital holographic imaging system, the propagation modes of a metallic coaxial waveguide are measured and the mode patterns are restored with the inverse Fresnel diffraction algorithm. The experimental results show that the THz propagation mode inside the waveguide is a combination of four modes TE₁₁, TE₁₂, TM₁₁, and TM₁₂, which are in good agreement with the simulation results. In this work, THz digital holography presents its strong potential as a platform for waveguide mode charactering. The experimental findings provide a valuable reference for the design of THz waveguides.

  13. Cool covered sky-splitting spectrum-splitting FK

    Energy Technology Data Exchange (ETDEWEB)

    Mohedano, Rubén; Chaves, Julio; Falicoff, Waqidi; Hernandez, Maikel; Sorgato, Simone [LPI, Altadena, CA, USA and Madrid (Spain); Miñano, Juan C.; Benitez, Pablo [LPI, Altadena, CA, USA and Madrid, Spain and Universidad Politécnica de Madrid (UPM), Madrid (Spain); Buljan, Marina [Universidad Politécnica de Madrid (UPM), Madrid (Spain)

    2014-09-26

    Placing a plane mirror between the primary lens and the receiver in a Fresnel Köhler (FK) concentrator gives birth to a quite different CPV system where all the high-tech components sit on a common plane, that of the primary lens panels. The idea enables not only a thinner device (a half of the original) but also a low cost 1-step manufacturing process for the optics, automatic alignment of primary and secondary lenses, and cell/wiring protection. The concept is also compatible with two different techniques to increase the module efficiency: spectrum splitting between a 3J and a BPC Silicon cell for better usage of Direct Normal Irradiance DNI, and sky splitting to harvest the energy of the diffuse radiation and higher energy production throughout the year. Simple calculations forecast the module would convert 45% of the DNI into electricity.

  14. Terminal load response law of coaxial cable to continuous wave electromagnetic irradiation

    International Nuclear Information System (INIS)

    Pan Xiaodong; Wei Guanghui; Li Xinfeng; Lu Xinfu

    2012-01-01

    In order to study the coupling response law of continuous wave electromagnetic irradiation to coaxial cable, the typical RF coaxial cable is selected as the object under test. The equipment or subsystem connected by coaxial cable is equivalent to a lumped load. Continuous wave irradiation effect experiments under different conditions are carried out to analyze the terminal load response law of coaxial cable. The results indicate that the coaxial cable has a frequency selecting characteristic under electromagnetic irradiation, and the terminal load response voltage peak appears at a series of discrete frequency points where the test cable's relative lengths equal to semi-integers. When the coaxial cable is irradiated by continuous wave, the induced sheath current converts to the differential-mode induced voltage between inner conductor and shielding layer through transfer impedance, and the internal resistance of induced voltage source is the characteristic impedance of the coaxial cable. The change in terminal load value has no influence on the response curve. The voltages on the terminal load and the internal resistance of equivalent induced voltage source obey the principle of voltage division. Moreover, when the sheath current on the coaxial cable is in resonance, the distributed induced voltage between adjacent current nodes is in the same polarity, which can be equivalent to a single induced voltage source. The induced voltage source which is adjacent to the terminal load plays the leading role in the irradiation response process. (authors)

  15. ITER ECFR Coaxial gyrotron and window development (EU-T360). Pt. 1: Coaxial gyrotron development. Final report

    International Nuclear Information System (INIS)

    Piosczyk, B.; Braz, O.; Dammertz, G.; Kuntze, G.; Michel, G.; Moebius, A.; Thumm, M.

    1999-02-01

    Based on the experience gained with the inverse magnetron injection gun (IMIG) for coaxial cavity gyrotrons, a new 4.5 MW electron gun for operation at a cathode voltage of 90 kV and a beam current of 50 A has been designed and is currently under fabrication at Thomson Tubes Electroniques (TTE). The gun is of the diode type. Different from the LaB 6 IMIG currently used, the emission of the electrons will not be directed towards the coaxial insert but towards the anode similar like in conventional MIG gyrotron electron guns. The inner conductor is supported from the gun inner conductor side and can be aligned in a reproducible way in the fully assembled tube. The insert is cooled as required for operation at long pulses up to cw. The cathode will be equipped with an impregnated tungsten matrix emitter as used in industrial tubes. A 160/170 GHz, 1.5 MW, 100 ms pulse length coaxial gyrotron employing the new electron gun and a single-stage depressed collector has been designed. The advanced quasi-optical converter for transforming the TE -31,17 cavity mode at 165 GHz into a single RF-output wave beam (only one output window) consists of a simple launcher and two mirrors. The first mirror is quasi-elliptical and the second mirror has a non-quadratic phase-correcting surface to generate an approximately homogeneous RF-field distribution with a high fundamental Gaussian content in the window plane. First test experiments with the new gyrotron have been performed employing the available LaB 6 -IMIG. (orig.)

  16. Coaxial stability of nano-bearings constructed by double-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Huang Zaixing

    2008-01-01

    How to effectively control the coaxial stability of nano-bearings has an important influence on improving the quality of nano-bearings. Some relevant problems are studied in this paper. Firstly, we investigate basic non-coaxial modes in double-wall carbon nanotubes (DWCNTs). On the basis of analysis for these non-coaxial modes, a planar continuum model is established according to the principle of homogenization. By means of this model, a dynamic parameter λ* characterizing the coaxial stability of nano-bearings is determined. λ* is the explicit function of the angular velocity and interlayer spacing of DWCNTs. In terms of λ*, a criterion used to judge the coaxial stability of nano-bearings is given. Through discussing the influence of the angular velocity and interlayer spacing on the dynamic parameter λ*, some important conclusions are drawn

  17. Numerical Simulation of Hydrogen Air Supersonic Coaxial Jet

    Science.gov (United States)

    Dharavath, Malsur; Manna, Pulinbehari; Chakraborty, Debasis

    2017-10-01

    In the present study, the turbulent structure of coaxial supersonic H2-air jet is explored numerically by solving three dimensional RANS equations along with two equation k-ɛ turbulence model. Grid independence of the solution is demonstrated by estimating the error distribution using Grid Convergence Index. Distributions of flow parameters in different planes are analyzed to explain the mixing and combustion characteristics of high speed coaxial jets. The flow field is seen mostly diffusive in nature and hydrogen diffusion is confined to core region of the jet. Both single step laminar finite rate chemistry and turbulent reacting calculation employing EDM combustion model are performed to find the effect of turbulence-chemistry interaction in the flow field. Laminar reaction predicts higher H2 mol fraction compared to turbulent reaction because of lower reaction rate caused by turbulence chemistry interaction. Profiles of major species and temperature match well with experimental data at different axial locations; although, the computed profiles show a narrower shape in the far field region. These results demonstrate that standard two equation class turbulence model with single step kinetics based turbulence chemistry interaction can describe H2-air reaction adequately in high speed flows.

  18. A numerical study of non-isothermal turbulent coaxial jets

    Energy Technology Data Exchange (ETDEWEB)

    Kriaa, Wassim; Abderrazak, Kamel; Mhiri, Hatem [Ecole Nationale d' Ingenieurs de Monastir, Laboratoire de Mecanique des Fluides et Thermique, Monastir (Tunisia); Palec, Georges le; Bournot, Philippe [Institut de Mecanique de Marseille, Marseille (France)

    2008-07-15

    In this work, we propose to study non isothermal air-air coaxial jets with two different approaches: parabolic and elliptic approaches. The standard k-{epsilon} model and the RSM model were applied in this study. The numerical resolution of the equations governing this flow type was carried out for: the parabolic approach, by a ''home-made'' CFD code based on a finite difference method, and the elliptic approach by an industrial code (FLUENT) based on a finite volume method. In forced convection mode (Fr={infinity}), the two turbulence models are valid for the prediction of the mean flow. But for turbulent sizes, k-{epsilon} model gives results closer to those achieved in experiments compared to RSM Model. Concerning the limit of validity of the parabolic and elliptic approaches, we showed that for velocities ratio r lower than 1, the results of the two approaches were satisfactory. On the other hand, for r>1, the difference between the results became increasingly significant. In mixed convection mode (Fr{approx_equal}20), the results obtained by the two turbulence models for the mean axial velocity were very different even in the plume region. For the temperature and the turbulent sizes the two models give satisfactory results which agree well with the correlations suggested by the experimenters for X{>=}20. Thus, the second order model with {sigma}{sub t}=0.85 is more effective for a coaxial jet study in a mixed convection mode. (orig.)

  19. Contoured-gap coaxial guns for imploding plasma liner experiments

    Science.gov (United States)

    Witherspoon, F. D.; Case, A.; Brockington, S.; Cassibry, J. T.; Hsu, S. C.

    2014-10-01

    Arrays of supersonic, high momentum flux plasma jets can be used as standoff compression drivers for generating spherically imploding plasma liners for driving magneto-inertial fusion, hence the name plasma-jet-driven MIF (PJMIF). HyperV developed linear plasma jets for the Plasma Liner Experiment (PLX) at LANL where two guns were successfully tested. Further development at HyperV resulted in achieving the PLX goal of 8000 μg at 50 km/s. Prior work on contoured-gap coaxial guns demonstrated an approach to control the blowby instability and achieved substantial performance improvements. For future plasma liner experiments we propose to use contoured-gap coaxial guns with small Minirailgun injectors. We will describe such a gun for a 60-gun plasma liner experiment. Discussion topics will include impurity control, plasma jet symmetry and topology (esp. related to uniformity and compactness), velocity capability, and techniques planned for achieving gun efficiency of >50% using tailored impedance matched pulse forming networks. Mach2 and UAH SPH code simulations will be included. Work supported by US DOE DE-FG02-05ER54810.

  20. A contoured gap coaxial plasma gun with injected plasma armature

    Energy Technology Data Exchange (ETDEWEB)

    Witherspoon, F. Douglas; Case, Andrew; Messer, Sarah J.; Bomgardner, Richard II; Phillips, Michael W.; Brockington, Samuel; Elton, Raymond [HyperV Technologies Corp., Chantilly, Virginia 20151 (United States)

    2009-08-15

    A new coaxial plasma gun is described. The long term objective is to accelerate 100-200 {mu}g of plasma with density above 10{sup 17} cm{sup -3} to greater than 200 km/s with a Mach number above 10. Such high velocity dense plasma jets have a number of potential fusion applications, including plasma refueling, magnetized target fusion, injection of angular momentum into centrifugally confined mirrors, high energy density plasmas, and others. The approach uses symmetric injection of high density plasma into a coaxial electromagnetic accelerator having an annular gap geometry tailored to prevent formation of the blow-by instability. The injected plasma is generated by numerous (currently 32) radially oriented capillary discharges arranged uniformly around the circumference of the angled annular injection region of the accelerator. Magnetohydrodynamic modeling identified electrode profiles that can achieve the desired plasma jet parameters. The experimental hardware is described along with initial experimental results in which approximately 200 {mu}g has been accelerated to 100 km/s in a half-scale prototype gun. Initial observations of 64 merging injector jets in a planar cylindrical testing array are presented. Density and velocity are presently limited by available peak current and injection sources. Steps to increase both the drive current and the injected plasma mass are described for next generation experiments.

  1. Numerical modeling of deflagration mode in coaxial plasma guns

    Science.gov (United States)

    Sitaraman, Hariswaran; Raja, Laxminarayan

    2012-10-01

    Pulsed coaxial plasma guns have been used in several applications in the field of space propulsion, nuclear fusion and materials processing. These devices operate in two modes based on the delay between gas injection and breakdown initiation. Larger delay led to the plasma detonation mode where a compression wave in the form of a luminous front propagates from the breech to the muzzle. Shorter delay led to the more efficient deflagration mode characterized by a relatively diffuse plasma with higher resistivity. The overall physics of the discharge in the two modes of operation and in particular the latter remain relatively unexplored. Here we perform a computational modeling study by solving the non-ideal Magneto-hydrodynamics equations for the quasi-neutral plasma in the coaxial plasma gun. A finite volume formulation on an unstructured mesh framework with an implicit scheme is used to do stable computations. The final work will present details of important species in the plasma, particle energies and Mach number at the muzzle. A comparison of the plasma parameters will be made with the experiments reported in ref. [1]. [4pt] [1] F. R. Poehlmann et al., Phys. Plasmas 17, 123508 (2010)

  2. Engineering design of the PLX- α coaxial gun

    Science.gov (United States)

    Cruz, E.; Brockington, S.; Case, A.; Luna, M.; Witherspoon, F. D.; Thio, Y. C. Francis; PLX-α Team

    2017-10-01

    We describe the engineering and technical improvements, as well as provide a detailed overview of the design choices, of the latest PLX- α coaxial gun designed for the 60-gun scaling study of spherically imploding plasma liners as a standoff driver for plasma-jet-driven magneto-inertial fusion. Each coaxial gun incorporates a fast, dense gas injection and triggering system, a compact low-weight pfn with integral sparkgap switching, and a contoured gap designed to suppress the blow-by instability. The evolution of the latest Alpha gun is presented with emphasis on its upgraded performance. Changes include a faster more robust gas valve, better-quality ceramic insulator material and enhancements to overall design layout. These changes result in a gun with increased repeatability, reduced potential failure modes, improved fault tolerance and better than expected efficiency. A custom 600- μF, 5-kV pfn and a set of six inline sparkgap switches operated in parallel are mounted directly to the back of the gun, and are designed to reduce inductance, cost, and complexity, maximize efficiency and system reliability, and ensure symmetric current flow. This work supported by the ARPA-E ALPHA Program under contract DE-AR0000566 and Strong Atomics, LLC.

  3. Tunable engineered skin mechanics via coaxial electrospun fiber core diameter.

    Science.gov (United States)

    Blackstone, Britani Nicole; Drexler, Jason William; Powell, Heather Megan

    2014-10-01

    Autologous engineered skin (ES) offers promise as a treatment for massive full thickness burns. Unfortunately, ES is orders of magnitude weaker than normal human skin causing it to be difficult to apply surgically and subject to damage by mechanical shear in the early phases of engraftment. In addition, no manufacturing strategy has been developed to tune ES biomechanics to approximate the native biomechanics at different anatomic locations. To enhance and tune ES biomechanics, a coaxial (CoA) electrospun scaffold platform was developed from polycaprolactone (PCL, core) and gelatin (shell). The ability of the coaxial fiber core diameter to control both scaffold and tissue mechanics was investigated along with the ability of the gelatin shell to facilitate cell adhesion and skin development compared to pure gelatin, pure PCL, and a gelatin-PCL blended fiber scaffold. CoA ES exhibited increased cellular adhesion and metabolism versus PCL alone or gelatin-PCL blend and promoted the development of well stratified skin with a dense dermal layer and a differentiated epidermal layer. Biomechanics of the scaffold and ES scaled linearly with core diameter suggesting that this scaffold platform could be utilized to tailor ES mechanics for their intended grafting site and reduce graft damage in vitro and in vivo.

  4. Coaxial nanocable composed by imogolite and carbon nanotubes

    International Nuclear Information System (INIS)

    Ramírez, M.; González, R. I.; Munoz, F.; Valdivia, J. A.; Rogan, J.; Kiwi, M.

    2015-01-01

    The discovery and development of Carbon Nanotubes (CNTs) at the beginning of the 1990s has driven a major part of solid state research. The electronic properties of the CNTs have generated a large number of ideas, as building coaxial nanocables. In this work we propose a possible type of such nanocables, which is formed by three nanostructures: two conducting CNTs, where one of them is covered by an insulator (an inorganic oxide nanotube: the imogolite aluminosilicate). The theoretical calculations were carried out using the density functional tight-binding formalism, by means of the DFTB+ code. This formalism allows to calculate the band structure, which compares favorably with DFT calculations, but with a significantly lower computational cost. As a first step, we reproduce the calculations of already published results, where the formation of a nanocable composed by one CNT and the imogolite as an insulator. Afterwards, we simulate the band structure for the proposed structure to study the feasibility of the coaxial nanocable. Finally, using classical MD simulations, we study the possible mechanisms of formation of these nanocables

  5. A contoured gap coaxial plasma gun with injected plasma armature.

    Science.gov (United States)

    Witherspoon, F Douglas; Case, Andrew; Messer, Sarah J; Bomgardner, Richard; Phillips, Michael W; Brockington, Samuel; Elton, Raymond

    2009-08-01

    A new coaxial plasma gun is described. The long term objective is to accelerate 100-200 microg of plasma with density above 10(17) cm(-3) to greater than 200 km/s with a Mach number above 10. Such high velocity dense plasma jets have a number of potential fusion applications, including plasma refueling, magnetized target fusion, injection of angular momentum into centrifugally confined mirrors, high energy density plasmas, and others. The approach uses symmetric injection of high density plasma into a coaxial electromagnetic accelerator having an annular gap geometry tailored to prevent formation of the blow-by instability. The injected plasma is generated by numerous (currently 32) radially oriented capillary discharges arranged uniformly around the circumference of the angled annular injection region of the accelerator. Magnetohydrodynamic modeling identified electrode profiles that can achieve the desired plasma jet parameters. The experimental hardware is described along with initial experimental results in which approximately 200 microg has been accelerated to 100 km/s in a half-scale prototype gun. Initial observations of 64 merging injector jets in a planar cylindrical testing array are presented. Density and velocity are presently limited by available peak current and injection sources. Steps to increase both the drive current and the injected plasma mass are described for next generation experiments.

  6. A contoured gap coaxial plasma gun with injected plasma armature

    International Nuclear Information System (INIS)

    Witherspoon, F. Douglas; Case, Andrew; Messer, Sarah J.; Bomgardner, Richard II; Phillips, Michael W.; Brockington, Samuel; Elton, Raymond

    2009-01-01

    A new coaxial plasma gun is described. The long term objective is to accelerate 100-200 μg of plasma with density above 10 17 cm -3 to greater than 200 km/s with a Mach number above 10. Such high velocity dense plasma jets have a number of potential fusion applications, including plasma refueling, magnetized target fusion, injection of angular momentum into centrifugally confined mirrors, high energy density plasmas, and others. The approach uses symmetric injection of high density plasma into a coaxial electromagnetic accelerator having an annular gap geometry tailored to prevent formation of the blow-by instability. The injected plasma is generated by numerous (currently 32) radially oriented capillary discharges arranged uniformly around the circumference of the angled annular injection region of the accelerator. Magnetohydrodynamic modeling identified electrode profiles that can achieve the desired plasma jet parameters. The experimental hardware is described along with initial experimental results in which approximately 200 μg has been accelerated to 100 km/s in a half-scale prototype gun. Initial observations of 64 merging injector jets in a planar cylindrical testing array are presented. Density and velocity are presently limited by available peak current and injection sources. Steps to increase both the drive current and the injected plasma mass are described for next generation experiments.

  7. Tunable Engineered Skin Mechanics via Coaxial Electrospun Fiber Core Diameter

    Science.gov (United States)

    Blackstone, Britani Nicole; Drexler, Jason William

    2014-01-01

    Autologous engineered skin (ES) offers promise as a treatment for massive full thickness burns. Unfortunately, ES is orders of magnitude weaker than normal human skin causing it to be difficult to apply surgically and subject to damage by mechanical shear in the early phases of engraftment. In addition, no manufacturing strategy has been developed to tune ES biomechanics to approximate the native biomechanics at different anatomic locations. To enhance and tune ES biomechanics, a coaxial (CoA) electrospun scaffold platform was developed from polycaprolactone (PCL, core) and gelatin (shell). The ability of the coaxial fiber core diameter to control both scaffold and tissue mechanics was investigated along with the ability of the gelatin shell to facilitate cell adhesion and skin development compared to pure gelatin, pure PCL, and a gelatin-PCL blended fiber scaffold. CoA ES exhibited increased cellular adhesion and metabolism versus PCL alone or gelatin-PCL blend and promoted the development of well stratified skin with a dense dermal layer and a differentiated epidermal layer. Biomechanics of the scaffold and ES scaled linearly with core diameter suggesting that this scaffold platform could be utilized to tailor ES mechanics for their intended grafting site and reduce graft damage in vitro and in vivo. PMID:24712409

  8. Coaxial nanocable composed by imogolite and carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Ramírez, M.; González, R. I.; Munoz, F.; Valdivia, J. A.; Rogan, J.; Kiwi, M. [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, 7800024 (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnología, CEDENNA, Avda. Ecuador 3493, Santiago, 9170124 (Chile)

    2015-12-31

    The discovery and development of Carbon Nanotubes (CNTs) at the beginning of the 1990s has driven a major part of solid state research. The electronic properties of the CNTs have generated a large number of ideas, as building coaxial nanocables. In this work we propose a possible type of such nanocables, which is formed by three nanostructures: two conducting CNTs, where one of them is covered by an insulator (an inorganic oxide nanotube: the imogolite aluminosilicate). The theoretical calculations were carried out using the density functional tight-binding formalism, by means of the DFTB+ code. This formalism allows to calculate the band structure, which compares favorably with DFT calculations, but with a significantly lower computational cost. As a first step, we reproduce the calculations of already published results, where the formation of a nanocable composed by one CNT and the imogolite as an insulator. Afterwards, we simulate the band structure for the proposed structure to study the feasibility of the coaxial nanocable. Finally, using classical MD simulations, we study the possible mechanisms of formation of these nanocables.

  9. Cherenkov radiation in a plasma-filled, dielectric coaxial waveguide

    International Nuclear Information System (INIS)

    Wu Jianqiang

    2004-01-01

    Using the self-consistent linear field theory, Cherenkov radiation excitated by the beam-wave interaction of a thin annular relativistic electron beam in a plasma-filled, dielectric coaxial cylindrical waveguide was analyzed. The dispersion equation of the interaction, the synchronized condition and the wave growth rate were derived. The energy exchange between the wave and the electron beam in the presence of background plasma was discussed, and the effects of plasma density on the dispersion characteristics, the wave growth rate and the beam-wave energy exchange were calculated and discussed. It was clear that the Cherenkov radiation results from the coupling between the slow TM mode propagated along the waveguide and the negative-energy space-charge mode propagated along the beam, and the coupling strength is proportional to the beam density. It was theoretically demonstrated that due to the background plasma, the plasma-filled coaxial cylindrical Cherenkov maser could operate at higher frequency, get higher wave growth rate, or have higher beam current at the same operating frequency, leading to higher microwave output power. (authors)

  10. Geothermal heat exchanger with coaxial flow of fluids

    Directory of Open Access Journals (Sweden)

    Pejić Dragan M.

    2005-01-01

    Full Text Available The paper deals with a heat exchanger with coaxial flow. Two coaxial pipes of the secondary part were placed directly into a geothermal boring in such a way that geothermal water flows around the outer pipe. Starting from the energy balance of the exchanger formed in this way and the assumption of a study-state operating regime, a mathematical model was formulated. On the basis of the model, the secondary circle output temperature was determined as a function of the exchanger geometry, the coefficient of heat passing through the heat exchange areas, the average mass isobaric specific heats of fluid and mass flows. The input temperature of the exchanger secondary circle and the temperature of the geothermal water at the exit of the boring were taken as known values. Also, an analysis of changes in certain factors influencing the secondary water temperature was carried out. The parameters (flow temperature of the deep boring B-4 in Sijarinska Spa, Serbia were used. The theoretical results obtained indicate the great potential of this boring and the possible application of such an exchanger.

  11. Development of 2.45GHz compact ECR ion sources with permanent magnets

    International Nuclear Information System (INIS)

    Tojyo, E.; Ohshiro, Y.; Oyaizu, M.; Shirakabe, Y.

    1993-05-01

    Two kinds of new compact ECR ion sources have been developed by use of permanent magnets only, for the purpose of acceleration tests of the 25.5MHz INS split coaxial RFQ linac and the 50MHz one. Confined magnetic fields of sources are constructed by permanent magnets only. In this paper design parameters, structures, magnetic field distributions and extracted beam properties of these sources are described briefly. (author)

  12. Geometrical Applications of Split Octonions

    Directory of Open Access Journals (Sweden)

    Merab Gogberashvili

    2015-01-01

    Full Text Available It is shown that physical signals and space-time intervals modeled on split-octonion geometry naturally exhibit properties from conventional (3 + 1-theory (e.g., number of dimensions, existence of maximal velocities, Heisenberg uncertainty, and particle generations. This paper demonstrates these properties using an explicit representation of the automorphisms on split-octonions, the noncompact form of the exceptional Lie group G2. This group generates specific rotations of (3 + 4-vector parts of split octonions with three extra time-like coordinates and in infinitesimal limit imitates standard Poincare transformations. In this picture translations are represented by noncompact Lorentz-type rotations towards the extra time-like coordinates. It is shown how the G2 algebra’s chirality yields an intrinsic left-right asymmetry of a certain 3-vector (spin, as well as a parity violating effect on light emitted by a moving quantum system. Elementary particles are connected with the special elements of the algebra which nullify octonionic intervals. Then the zero-norm conditions lead to free particle Lagrangians, which allow virtual trajectories also and exhibit the appearance of spatial horizons governing by mass parameters.

  13. 2-Photon tandem device for water splitting

    DEFF Research Database (Denmark)

    Seger, Brian; Castelli, Ivano Eligio; Vesborg, Peter Christian Kjærgaard

    2014-01-01

    Within the field Of photocatalytic water splitting there are several strategies to achieve the goal of efficient and cheap photocatalytic water splitting. This work examines one particular strategy by focusing on monolithically stacked, two-photon photoelectrochemical cells. The overall aim...... for photocatalytic water splitting by using a large bandgap photocathode and a low bandgap photoanode with attached protection layers....

  14. Construction and building of a compact RFQ spiral structure for the stopping of highly charged heavy ion beams for the HITRAP project of the GSI; Konstruktion und Aufbau einer kompakten RFQ-Spiral-Struktur zum Abbremsen hochgeladener Schwerionenstrahlen fuer das HITRAP-Projekt der GSI

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, B.

    2007-07-01

    For experiments of the atomic-physics group of the GSI in Darmstadt an ion stopper is built, which will make low-energetic, extremely highly charged ions available. The plannings for the so-called HITRAP (highly charged ion's trap) began at the beginning of the ninetieth. With this facility highly-charged heavy ions shall be stopped in two stages to very low, thermal velocities, and be available for highly precise mass spectroscopy, measurements of the g factor of the bound electron of hydrogen-like ions, and other atomic-physics experiments. This decelerator facility shall first be built in the reinjection channel behind the ESR with the possibility, to apply all components later in teh extension of the GSI in the framework of the FAIR project in the facility for low-energetic antiprotons and ions to be newly built. the present thesis treats the development and the building of an integrated RFQ debuncher stopping accelerator, which represents a part of the HITRAP stopping structures. By this the ion beam is stopped from the IH stopping accelerator with an energy of 500 keV/u to 5 keV/u. By the integrated spiral buncher the beam can be fitted in energy and energy deviation to the subsequent cooler trap. In this thesis the foundations of the particle dynamics in a RFQ accelerator for the stopping of particle beams were worked out and realized, the particle-dynamics calculations necessary for the lay-out of such a structure performed with RFQSim, suitable RF structures with the simulation program Microwave Studio developed and studied, as well as the thermal load of the structures studied with the finite-element code ALGOR. A further, central topic of this thesis is the building and the tuning of the RFQ structure in order to reach a homogeneous as possible field distribution along the electrodes. Measurements of the fields in the RFQ were performed with a disturbing condenser, at the debuncher with a disturbing body. After successfully performed vacuum tests at

  15. Segmentation of the Outer Contact on P-Type Coaxial Germanium Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Hull, Ethan L.; Pehl, Richard H.; Lathrop, James R.; Martin, Gregory N.; Mashburn, R. B.; Miley, Harry S.; Aalseth, Craig E.; Hossbach, Todd W.

    2006-09-21

    Germanium detector arrays are needed for low-level counting facilities. The practical applications of such user facilities include characterization of low-level radioactive samples. In addition, the same detector arrays can also perform important fundamental physics measurements including the search for rare events like neutrino-less double-beta decay. Coaxial germanium detectors having segmented outer contacts will provide the next level of sensitivity improvement in low background measurements. The segmented outer detector contact allows performance of advanced pulse shape analysis measurements that provide additional background reduction. Currently, n-type (reverse electrode) germanium coaxial detectors are used whenever a segmented coaxial detector is needed because the outer boron (electron barrier) contact is thin and can be segmented. Coaxial detectors fabricated from p-type germanium cost less, have better resolution, and are larger than n-type coaxial detectors. However, it is difficult to reliably segment p-type coaxial detectors because thick (~1 mm) lithium-diffused (hole barrier) contacts are the standard outside contact for p-type coaxial detectors. During this Phase 1 Small Business Innovation Research (SBIR) we have researched the possibility of using amorphous germanium contacts as a thin outer contact of p-type coaxial detectors that can be segmented. We have developed amorphous germanium contacts that provide a very high hole barrier on small planar detectors. These easily segmented amorphous germanium contacts have been demonstrated to withstand several thousand volts/cm electric fields with no measurable leakage current (<1 pA) from charge injection over the hole barrier. We have also demonstrated that the contact can be sputter deposited around and over the curved outside surface of a small p-type coaxial detector. The amorphous contact has shown good rectification properties on the outside of a small p-type coaxial detector. These encouraging

  16. Development and optimization of a four-rod RFQ accelerator for light ions - construction and testing of a H--injector for HERA

    International Nuclear Information System (INIS)

    Ferch, M.

    1987-01-01

    In the framework of the present thesis the RF properties of a new RFQ accelerator structure were studied and optimized. After a short section about the foundations of the acceleration with RFQ resonators and the description of the most important general structure properties the operation of the λ/2 resonator in the construction developed here is described. For the quantitative description of the RF properties a theoretical model was developed which describes the RF-structure parameters with sufficient accuracy and is furthermore useful in the planning of further RF projects. For the detailed study of the oscillation shape and the field distributions resulting from this especially in the region of the quadrupolarly arranged beam guiding elements special measuring methods were improved respectively newly developed. With the knowledge resulting from this the efficiency as well as the stability of the acceleration and focusing fields could be optimized. The high-power resonator constructed in the framework of this thesis operates at a resonance frequency of 202.56 MHz and is layed out for pulsed operation. Corresponding to this only into the ground rail a cooling loop was integrated. The electrodes are rod-shaped performed. The in the ideal case sinus-shaped modulation profile of the quadrupole electrodes was approximated by a trapezoidal approximation. (orig./HSI) [de

  17. Innovative wedge axe in making split firewood

    International Nuclear Information System (INIS)

    Mutikainen, A.

    1998-01-01

    Interteam Oy, a company located in Espoo, has developed a new method for making split firewood. The tools on which the patented System Logmatic are based are wedge axe and cylindrical splitting-carrying frame. The equipment costs about 495 FIM. The block of wood to be split is placed inside the upright carrying frame and split in a series of splitting actions using the innovative wedge axe. The finished split firewood remains in the carrying frame, which (as its name indicates) also serves as the means for carrying the firewood. This innovative wedge-axe method was compared with the conventional splitting of wood using an axe (Fiskars -handy 1400 splitting axe costing about 200 FIM) in a study conducted at TTS-Institute. There were eight test subjects involved in the study. In the case of the wedge-axe method, handling of the blocks to be split and of the finished firewood was a little quicker, but in actual splitting it was a little slower than the conventional axe method. The average productivity of splitting the wood and of the work stages related to it was about 0.4 m 3 per effective hour in both methods. The methods were also equivalent of one another in terms of the load imposed by the work when measured in terms of the heart rate. As regards work safety, the wedge-axe method was superior to the conventional method, but the continuous striking action and jolting transmitted to the arms were unpleasant (orig.)

  18. NOx emission characteristics in turbulent hydrogen jet flames with coaxial air

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Hee Jang [Korea Aerospace University, Goyang (Korea, Republic of); Park, Yang Ho; Yoon, Young Bin [Seoul National University, Seoul (Korea, Republic of)

    2009-06-15

    The characteristics of NOx emissions in pure hydrogen nonpremixed jet flames with coaxial air are analyzed numerically for a wide range of coaxial air conditions. Among the models tested in simple nonpremixed jet flame, the one-half power scaling law could be reproduced only by the Model C using the HO{sub 2}/H{sub 2}O{sub 2} reaction, implying the importance of chemical nonequilibrium effect. The flame length is reduced significantly by augmenting coaxial air, and could be represented as a function of the ratio of coaxial air to fuel velocity. Predicted EINOx scaling showed a good concordance with experimental data, and the overall one-half power scaling was observed in coaxial flames with Model C when flame residence time was defined with flame volume instead of a cubic of the flame length. Different level of oxygen mass fraction at the stoichiometric surface was observed as coaxial air was increased. These different levels imply that the coaxial air strengthens the nonequilibrium effect

  19. Analysis of flame shapes in turbulent hydrogen jet flames with coaxial air

    International Nuclear Information System (INIS)

    Moon, Hee Jang

    2009-01-01

    This paper addresses the characteristics of flame shapes and flame length in three types of coaxial air flames realizable by varying coaxial air and/or fuel velocity. Forcing coaxial air into turbulent jet flames induces substantial changes in flame shapes and NOx emissions through the complex flow interferences that exist within the mixing region. Mixing enhancement driven by coaxial air results in flame volume decrease, and such a diminished flame volume finally reduces NOx emissions significantly by decreasing NOx formation zone where a fuel/air mixture burns. It is found that mixing in the vicinity of high temperature zone mainly results from the increase of diffusive flux than the convective flux, and that the increase of mass diffusion is amplified as coaxial air is increased. Besides, it is reaffirmed that nonequilibrium chemistry including HO 2 /H 2 O 2 should be taken into account for NOx prediction and scaling analysis by comparing turbulent combustion models. In addition, it is found that coaxial air can break down the self-similarity law of flames by changing mixing mechanism, and that EINOx scaling parameters based on the self-similarity law of simple jet flames may not be eligible in coaxial air flames

  20. Analysis of flame shapes in turbulent hydrogen jet flames with coaxial air

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Hee Jang [Korea Aerospace University, Goyang (Korea, Republic of)

    2009-06-15

    This paper addresses the characteristics of flame shapes and flame length in three types of coaxial air flames realizable by varying coaxial air and/or fuel velocity. Forcing coaxial air into turbulent jet flames induces substantial changes in flame shapes and NOx emissions through the complex flow interferences that exist within the mixing region. Mixing enhancement driven by coaxial air results in flame volume decrease, and such a diminished flame volume finally reduces NOx emissions significantly by decreasing NOx formation zone where a fuel/air mixture burns. It is found that mixing in the vicinity of high temperature zone mainly results from the increase of diffusive flux than the convective flux, and that the increase of mass diffusion is amplified as coaxial air is increased. Besides, it is reaffirmed that nonequilibrium chemistry including HO{sub 2}/H{sub 2}O{sub 2} should be taken into account for NOx prediction and scaling analysis by comparing turbulent combustion models. In addition, it is found that coaxial air can break down the self-similarity law of flames by changing mixing mechanism, and that EINOx scaling parameters based on the self-similarity law of simple jet flames may not be eligible in coaxial air flames

  1. Modified coaxial wire method for measurement of transfer impedance of beam position monitors

    Science.gov (United States)

    Kumar, Mukesh; Babbar, L. K.; Deo, R. K.; Puntambekar, T. A.; Senecha, V. K.

    2018-05-01

    The transfer impedance is a very important parameter of a beam position monitor (BPM) which relates its output signal with the beam current. The coaxial wire method is a standard technique to measure transfer impedance of the BPM. The conventional coaxial wire method requires impedance matching between coaxial wire and external circuits (vector network analyzer and associated cables). This paper presents a modified coaxial wire method for bench measurement of the transfer impedance of capacitive pickups like button electrodes and shoe box BPMs. Unlike the conventional coaxial wire method, in the modified coaxial wire method no impedance matching elements have been used between the device under test and the external circuit. The effect of impedance mismatch has been solved mathematically and a new expression of transfer impedance has been derived. The proposed method is verified through simulation of a button electrode BPM using cst studio suite. The new method is also applied to measure transfer impedance of a button electrode BPM developed for insertion devices of Indus-2 and the results are also compared with its simulations. Close agreement between measured and simulation results suggests that the modified coaxial wire setup can be exploited for the measurement of transfer impedance of capacitive BPMs like button electrodes and shoe box BPM.

  2. Modified coaxial wire method for measurement of transfer impedance of beam position monitors

    Directory of Open Access Journals (Sweden)

    Mukesh Kumar

    2018-05-01

    Full Text Available The transfer impedance is a very important parameter of a beam position monitor (BPM which relates its output signal with the beam current. The coaxial wire method is a standard technique to measure transfer impedance of the BPM. The conventional coaxial wire method requires impedance matching between coaxial wire and external circuits (vector network analyzer and associated cables. This paper presents a modified coaxial wire method for bench measurement of the transfer impedance of capacitive pickups like button electrodes and shoe box BPMs. Unlike the conventional coaxial wire method, in the modified coaxial wire method no impedance matching elements have been used between the device under test and the external circuit. The effect of impedance mismatch has been solved mathematically and a new expression of transfer impedance has been derived. The proposed method is verified through simulation of a button electrode BPM using cst studio suite. The new method is also applied to measure transfer impedance of a button electrode BPM developed for insertion devices of Indus-2 and the results are also compared with its simulations. Close agreement between measured and simulation results suggests that the modified coaxial wire setup can be exploited for the measurement of transfer impedance of capacitive BPMs like button electrodes and shoe box BPM.

  3. Event timing in high purity germanium coaxial detectors

    International Nuclear Information System (INIS)

    El-Ibiary, M.Y.

    1979-08-01

    The timing of gamma ray radiation in systems using high purity coaxial germanium detectors is analyzed and compared to that of systems using Ge(Li) detectors. The analysis takes into account the effect of the residual impurities on the electric field distribution, and hence on the rate of rise of the electrical pulses delivered to the timing module. Conditions under which the electric field distribution could lead to an improvement in timing performance, are identified. The results of the analysis confirm the experimental results published elsewhere and when compared with those for Ge(Li) detectors, which usually operate under conditions of charge carrier velocity saturation, confirm that high purity germanium detectors need not have inferior timing characteristics. A chart is given to provide a quantitative basis on which the trade off between the radius of the detector and its time resolution may be made

  4. Velocity limitations in coaxial plasma gun experiments with gas mixtures

    International Nuclear Information System (INIS)

    Axnaes, I.

    1976-04-01

    The velocity limitations found in many crossed field plasma experiments with neutral gas present are studied for binary mixtures of H 2 , He, N 2 O 2 , Ne and Ar. The apparatus used is a coaxial plasma gun with an azimuthal magnetic bias field. The discharge parameters are chosen so that the plasma is weakly ionized. In some of the mixtures it is found that one of the components tends to dominate in the sense that only a small amount (regarding volume) of that component is needed for the discharge to adopt a limiting velocity close to that for the pure component. Thus in a mixture between a heavy and a light component having nearly equal ionization potentials the heavy component dominates. Also if there is a considerable difference in ionization potential between the components, the component with the lowest ionization potential tends to dominate. (author)

  5. Coaxial carbon plasma gun deposition of amorphous carbon films

    Science.gov (United States)

    Sater, D. M.; Gulino, D. A.; Rutledge, S. K.

    1984-01-01

    A unique plasma gun employing coaxial carbon electrodes was used in an attempt to deposit thin films of amorphous diamond-like carbon. A number of different structural, compositional, and electrical characterization techniques were used to characterize these films. These included scanning electron microscopy, scanning transmission electron microscopy, X ray diffraction and absorption, spectrographic analysis, energy dispersive spectroscopy, and selected area electron diffraction. Optical absorption and electrical resistivity measurements were also performed. The films were determined to be primarily amorphous, with poor adhesion to fused silica substrates. Many inclusions of particulates were found to be present as well. Analysis of these particulates revealed the presence of trace impurities, such as Fe and Cu, which were also found in the graphite electrode material. The electrodes were the source of these impurities. No evidence of diamond-like crystallite structure was found in any of the film samples. Details of the apparatus, experimental procedure, and film characteristics are presented.

  6. Simulative research on reverse current in magnetically insulated coaxial diode

    Directory of Open Access Journals (Sweden)

    Danni Zhu

    2017-10-01

    Full Text Available The reverse current tends to occur in the transition region of the guiding magnetic field in a magnetically insulated coaxial diode (MICD. Influence of the guiding magnetic field on characteristics of the MICD especially on the reverse current is studied by the particle-in-cell (PIC simulation in this paper. The reverse current is confirmed to be irrelevant with the guiding magnetic field strength. However, the reverse current is clarified quantitatively to depend on the electric and magnetic field distribution in the upstream of the cathode tip. As the MICD has been widely employed in microwave tubes, a simple approach to suppress the reverse current on the premise of little change of the original diode is valuable and thus proposed. The optimum matching point between the cathode and the magnetic field is selected in consideration of the entrance depth tolerance, the diode impedance discrepancy and the reverse current coefficient.

  7. Ultra-wideband, omni-directional, low distortion coaxial antenna

    Science.gov (United States)

    Eubanks, Travis Wayne; Gibson, Christopher Lawrence

    2015-01-06

    An antenna for producing an omni-directional pattern, and using all frequencies of a frequency range simultaneously, is provided with first and second electrically conductive elements disposed coaxially relative to a central axis. The first element has a first surface of revolution about the axis, the first surface of revolution tapering radially outwardly while extending axially away from the second element to terminate at a first axial end of the first element. The second element has a second surface of revolution about the axis, the second surface of revolution tapering radially outwardly while extending axially toward the first element to terminate at a first axial end of the second element. The first and second surfaces of revolution overlap one another radially and axially, and are mutually non-conformal.

  8. Preparation and characterization of CdS/Si coaxial nanowires

    Science.gov (United States)

    Fu, X. L.; Li, L. H.; Tang, W. H.

    2006-04-01

    CdS/Si coaxial nanowires were fabricated via a simple one-step thermal evaporation of CdS powder in mass scale. Their crystallinities, general morphologies and detailed microstructures were characterized by using X-ray diffraction, scanning electron microscope, transmission electron microscope and Raman spectra. The CdS core crystallizes in a hexagonal wurtzite structure with lattice constants of a=0.4140 nm and c=0.6719 nm, and the Si shell is amorphous. Five Raman peaks from the CdS core were observed. They are 1LO at 305 cm -1, 2LO at 601 cm -1, A 1-TO at 212 cm -1, E 1-TO at 234 cm -1, and E 2 at 252 cm -1. Photoluminescence measurements show that the nanowires have two emission bands around 510 and 590 nm, which originate from the intrinsic transitions of CdS cores and the amorphous Si shells, respectively.

  9. Coaxial carbon plasma gun deposition of amorphous carbon films

    International Nuclear Information System (INIS)

    Sater, D.M.; Gulino, D.A.

    1984-03-01

    A unique plasma gun employing coaxial carbon electrodes was used in an attempt to deposit thin films of amorphous diamond-like carbon. A number of different structural, compositional, and electrical characterization techniques were used to characterize these films. These included scanning electron microscopy, scanning transmission electron microscopy, X ray diffraction and absorption, spectrographic analysis, energy dispersive spectroscopy, and selected area electron diffraction. Optical absorption and electrical resistivity measurements were also performed. The films were determined to be primarily amorphous, with poor adhesion to fused silica substrates. Many inclusions of particulates were found to be present as well. Analysis of these particulates revealed the presence of trace impurities, such as Fe and Cu, which were also found in the graphite electrode material. The electrodes were the source of these impurities. No evidence of diamond-like crystallite structure was found in any of the film samples. Details of the apparatus, experimental procedure, and film characteristics are presented

  10. High spatial resolution Kelvin probe force microscopy with coaxial probes

    International Nuclear Information System (INIS)

    Brown, Keith A; Westervelt, Robert M; Satzinger, Kevin J

    2012-01-01

    Kelvin probe force microscopy (KPFM) is a widely used technique to measure the local contact potential difference (CPD) between an AFM probe and the sample surface via the electrostatic force. The spatial resolution of KPFM is intrinsically limited by the long range of the electrostatic interaction, which includes contributions from the macroscopic cantilever and the conical tip. Here, we present coaxial AFM probes in which the cantilever and cone are shielded by a conducting shell, confining the tip–sample electrostatic interaction to a small region near the end of the tip. We have developed a technique to measure the true CPD despite the presence of the shell electrode. We find that the behavior of these probes agrees with an electrostatic model of the force, and we observe a factor of five improvement in spatial resolution relative to unshielded probes. Our discussion centers on KPFM, but the field confinement offered by these probes may improve any variant of electrostatic force microscopy. (paper)

  11. Coaxial monitoring of temperature field in selective pulsed laser melting

    Science.gov (United States)

    Liu, Che; Chen, Zhongyun; Cao, Hongzhong; Zhou, Jianhong

    2017-10-01

    Selective Laser Melting is a rapid manufacturing technology which produces complex parts layer by layer. The presence of thermal stress and thermal strain in the forming process often leads to defects in the formed parts. In order to detect fabricate errors and avoid failure which caused by thermal gradient in time. An infrared thermal imager and a high speed CCD camera were applied to build a coaxial optical system for real-time monitoring the temperature distribution and changing trend of laser affected zone in SLM forming process. Molten tracks were fabricated by SLM under different laser parameters such as frequency, pulse width. And the relationship between the laser parameters and the temperature distribution were all obtained and analyzed.

  12. Propellant Feed System for Swirl-Coaxial Injection

    Science.gov (United States)

    Reynolds, David Christopher (Inventor)

    2015-01-01

    A propellant feed system for swirl-coaxial injection of a liquid propellant includes a reservoir having a bottom plate and at least one tube originating in the bottom plate and extending therefrom. The tube has rectangular slits defined in and distributed tangentially and evenly about a portion of the tube that is disposed in the bottom plate. Drain holes are provided in the bottom plate and tunnels are defined in the bottom plate. Each tunnel fluidly couples one of the drain holes to a corresponding one of the rectangular slits. Each tunnel includes (i) a bend of at least 90.degree., and (ii) a straight portion leading to its corresponding rectangular slit wherein the straight portion is at least five times as long as a hydraulic diameter of the corresponding rectangular slit.

  13. A typology of split conjunction

    OpenAIRE

    Palancar , Enrique L.

    2012-01-01

    International audience; In this paper, I study instances of noun phrase conjunction where the conjoined noun phrase is subject and the referents of the conjuncts are human, of the type ‘John and Mary are having lunch’. More specifically, I study different, possible splits that occur in such structures, which involve the disruption of the phrasal continuity of the conjuncts, resulting in structures roughly equivalent to ‘they are having lunch with Mary’ and ‘John are having lunch with Mary’. I...

  14. Modeling of thermalization phenomena in coaxial plasma accelerators

    Science.gov (United States)

    Subramaniam, Vivek; Panneerchelvam, Premkumar; Raja, Laxminarayan L.

    2018-05-01

    Coaxial plasma accelerators are electromagnetic acceleration devices that employ a self-induced Lorentz force to produce collimated plasma jets with velocities ~50 km s‑1. The accelerator operation is characterized by the formation of an ionization/thermalization zone near gas inlet of the device that continually processes the incoming neutral gas into a highly ionized thermal plasma. In this paper, we present a 1D non-equilibrium plasma model to resolve the plasma formation and the electron-heavy species thermalization phenomena that take place in the thermalization zone. The non-equilibrium model is based on a self-consistent multi-species continuum description of the plasma with finite-rate chemistry. The thermalization zone is modelled by tracking a 1D gas-bit as it convects down the device with an initial gas pressure of 1 atm. The thermalization process occurs in two stages. The first is a plasma production stage, associated with a rapid increase in the charged species number densities facilitated by cathode surface electron emission and volumetric production processes. The production stage results in the formation of a two-temperature plasma with electron energies of ~2.5 eV in a low temperature background gas of ~300 K. The second, a temperature equilibration stage, is characterized by the energy transfer between the electrons and heavy species. The characteristic length scale for thermalization is found to be comparable to axial length of the accelerator thus putting into question the equilibrium magnetohydrodynamics assumption used in modeling coaxial accelerators.

  15. Coaxial Mono-Energetic Gamma Generator for Active Interrogation

    International Nuclear Information System (INIS)

    Ludewigt, Bernhard A.; Antolak, A.J.; Henestroza, E.; Leitner, M.; Leung, K.-N.; Waldron, W.; Wilde, S.; Kwan, J.W.

    2008-01-01

    Compact mono-energetic photon sources are sought for active interrogation systems to detect shielded special nuclear materials in, for example, cargo containers, trucks and other vehicles. A prototype gamma interrogation source has been designed and built that utilizes the 11B(p,gamma)12C reaction to produce 12 MeV gamma-rays which are near the peak of the photofission cross section. In particular, the 11B(p,gamma)12C resonance at 163 kV allows the production of gammas at low proton acceleration voltages, thus keeping the design of a gamma generator comparatively small and simple. A coaxial design has been adopted with a toroidal-shaped plasma chamber surrounding a cylindrical gamma production target. The plasma discharge is driven by a 2 MHz rf-power supply (capable up to 50 kW) using a circular rf-antenna. Permanent magnets embedded in the walls of the plasma chamber generate a multi-cusp field that confines the plasma and allows higher plasma densities and lower gas pressures. About 100 proton beamlets are extracted through a slotted plasma electrode towards the target at the center of the device that is at a negative 180 kV. The target consists of LaB6 tiles that are brazed to a water-cooled cylindrical structure. The generator is designed to operate at 500 Hz with 20 mu s long pulses, and a 1percent duty factor by pulsing the ion source rf-power. A first-generation coaxial gamma source has been built for low duty factor experiments and testing.

  16. Algebraic techniques for diagonalization of a split quaternion matrix in split quaternionic mechanics

    International Nuclear Information System (INIS)

    Jiang, Tongsong; Jiang, Ziwu; Zhang, Zhaozhong

    2015-01-01

    In the study of the relation between complexified classical and non-Hermitian quantum mechanics, physicists found that there are links to quaternionic and split quaternionic mechanics, and this leads to the possibility of employing algebraic techniques of split quaternions to tackle some problems in complexified classical and quantum mechanics. This paper, by means of real representation of a split quaternion matrix, studies the problem of diagonalization of a split quaternion matrix and gives algebraic techniques for diagonalization of split quaternion matrices in split quaternionic mechanics

  17. A steady-state fluid model of the coaxial plasma gun

    International Nuclear Information System (INIS)

    Herziger, G.; Krompholz, H.; Schneider, W.; Schoenbach, K.

    1979-01-01

    The plasma layer in a coaxial plasma gun is considered as a shock front driven by expanding magnetic fields. Analytical steady-state solutions of the fluid equations yield the plasma properties, allowing the scaling of plasma focus devices. (Auth.)

  18. Startup of reversed-field mirror reactors using coaxial plasma guns

    International Nuclear Information System (INIS)

    Smith, A.C. Jr.; Hartman, C.W.; Carlson, G.A.; Neef, W.S. Jr.; Eddleman, J.L.

    1979-01-01

    Preliminary calculations are given that indicate that a coaxial plasma gun might scale reasonably to reactor-grade operating conditions. Ongoing experiments and numerical simulations should shed some light on the validity of the described scaling laws

  19. Coaxial plasma guns as injectors of high beta linear theta pinches

    International Nuclear Information System (INIS)

    Marshall, J.

    1975-01-01

    A brief review of research on coaxial plasma guns and their use is given. Some problems and possibilities of using this gun for beam injection experiments are pointed out. Some scaling laws for gun energy are described

  20. Clinical application of multi-detector CT-guided percutaneous coaxial biopsy for pulmonary lesions

    International Nuclear Information System (INIS)

    Jia Ningyang; Liu Shiyuan; Zhang Dianbo; Xiao Xiangsheng; Li Wentao; Li Chenzhou

    2008-01-01

    Objective: To evaluate the clinical application of multi-slice CT-guided percutaneous transthoracic lung coaxial-biopsy for pulmonary lesions. Methods: 152 times of 143 patients were performed with percutaneous transthoracic coaxial biopsy under multiple-slice CT-guidance. Analysis was carried out to investigate the diagnostic accuracy and the relationship between the size of the lesions for coaxial biopsy, together with the complications. Results: The diagnostic accuracy was 94.9% with specificity of 100%, including malignant tumors 116 cases (squamous cell cancer 48 cases, adenocarcinoma 34, small cell undifferentiated carcinoma 6, large cell carcinoma 4, bronchial alveolar carcinoma 8, metastatic carcinoma 16) and 19 cases of benign ones(TB 7 cases, inflammatory pseudotumor 9, hematoma 1, lung abscess 1). The size of lesion had a significant influence on the diagnostic accuracy. Conclusions: Percutaneous transthoracic coaxial lung biopsy is a safety method, possessing a high diagnostic accuracy. (authors)

  1. An experimental study of the supersonic, dual, coaxial jets impinging on an inclined flat plate

    International Nuclear Information System (INIS)

    Kim, Jung Bae; Lee, Jun Hee; Woo, Sun Hoon; Kim, Heuy Dong

    2002-01-01

    The impinging supersonic jets have been applied for rocket launching system, thrust control, gas turbine blade cooling, etc. Recently the supersonic, dual, coaxial jets are being extensively used in many diverse fields of industrial processes since they lead to more improved performance, compared with the conventional supersonic jets impinging on an object. In the present study, experimentation is carried out to investigate the supersonic, dual, coaxial jets impinging on an inclined flat plate. A convergent-divergent nozzle with a design Mach number of 2.0 and annular sonic nozzle are used to make the dual, coaxial jet flows. The angle of the impinging flat plate is varied from 30 .deg. to 60 .deg. and the distance between the dual coaxial nozzle and flat plate is also varied. Detailed pressures on the impinging plate are measured to analyze the flow fields, which are also visualized using Schlieren optical method

  2. Coaxial Tubing Systems Increase Artificial Airway Resistance and Work of Breathing.

    Science.gov (United States)

    Wenzel, Christin; Schumann, Stefan; Spaeth, Johannes

    2017-09-01

    Tubing systems are an essential component of the ventilation circuit, connecting the ventilator to the patient's airways. Coaxial tubing systems incorporate the inspiratory tube within the lumen of the expiratory one. We hypothesized that by design, these tubing systems increase resistance to air flow compared with conventional ones. We investigated the flow-dependent pressure gradient across coaxial, conventional disposable, and conventional reusable tubing systems from 3 different manufacturers. Additionally, the additional work of breathing and perception of resistance during breathing through the different devices were determined in 18 healthy volunteers. The pressure gradient across coaxial tubing systems was up to 6 times higher compared with conventional ones (1.90 ± 0.03 cm H 2 O vs 0.34 ± 0.01 cm H 2 O, P tubing systems, accordingly. Our findings suggest that the use of coaxial tubing systems should be carefully considered with respect to their increased resistance. Copyright © 2017 by Daedalus Enterprises.

  3. Analytical calculations of the efficiency of gamma scintillators total efficiency for coaxial disk sources

    Energy Technology Data Exchange (ETDEWEB)

    Selim, Y S; Abbas, M I; Fawzy, M A [Physics Department, Faculty of Science, Alexandria University, Aleaxndria (Egypt)

    1997-12-31

    Total efficiency of clad right circular cylindrical Nal(TI) scintillation detector from a coaxial isotropic radiating circular disk source has been calculated by the of rigid mathematical expressions. Results were tabulated for various gamma energies. 2 figs., 5 tabs.

  4. Optimal estimation of ship's attitudes for beampattern corrections in a coaxial circular array

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Dev, K.K.

    A study is conducted to estimate the accurate attitude of a ship's motion and the estimation is used to arrive at the corrections required for a farfield pattern of a coaxial circular array. The relevant analytical expression is developed...

  5. Additive operator-difference schemes splitting schemes

    CERN Document Server

    Vabishchevich, Petr N

    2013-01-01

    Applied mathematical modeling isconcerned with solving unsteady problems. This bookshows how toconstruct additive difference schemes to solve approximately unsteady multi-dimensional problems for PDEs. Two classes of schemes are highlighted: methods of splitting with respect to spatial variables (alternating direction methods) and schemes of splitting into physical processes. Also regionally additive schemes (domain decomposition methods)and unconditionally stable additive schemes of multi-component splitting are considered for evolutionary equations of first and second order as well as for sy

  6. Iterative Splitting Methods for Differential Equations

    CERN Document Server

    Geiser, Juergen

    2011-01-01

    Iterative Splitting Methods for Differential Equations explains how to solve evolution equations via novel iterative-based splitting methods that efficiently use computational and memory resources. It focuses on systems of parabolic and hyperbolic equations, including convection-diffusion-reaction equations, heat equations, and wave equations. In the theoretical part of the book, the author discusses the main theorems and results of the stability and consistency analysis for ordinary differential equations. He then presents extensions of the iterative splitting methods to partial differential

  7. On the jets, kinks, and spheromaks formed by a planar magnetized coaxial gun

    OpenAIRE

    Hsu, S. C.; Bellan, P. M.

    2005-01-01

    Measurements of the various plasma configurations produced by a planar magnetized coaxial gun provide insight into the magnetic topology evolution resulting from magnetic helicity injection. Important features of the experiments are a very simple coaxial gun design so that all observed geometrical complexity is due to the intrinsic physical dynamics rather than the source shape and use of a fast multiple-frame digital camera which provides direct imaging of topologically complex shapes and dy...

  8. Novel electric double-layer capacitor with a coaxial fiber structure.

    Science.gov (United States)

    Chen, Xuli; Qiu, Longbin; Ren, Jing; Guan, Guozhen; Lin, Huijuan; Zhang, Zhitao; Chen, Peining; Wang, Yonggang; Peng, Huisheng

    2013-11-26

    A coaxial electric double-layer capacitor fiber is developed from the aligned carbon nanotube fiber and sheet, which functions as two electrodes with a polymer gel sandwiched between them. The unique coaxial structure enables a rapid transportation of ions between the two electrodes with a high electrochemical performance. These energy storage fibers are also flexible and stretchable, and can be woven into and widely used for electronic textiles. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Microwave generation enhancement of X-band CRBWO by use of coaxial dual annular cathodes

    OpenAIRE

    Yan Teng; Jun Sun; Changhua Chen; Hao Shao

    2013-01-01

    This paper presents an approach that greatly enhances both the output power and the conversion efficiency of the coaxial relativistic backward wave oscillator (CRBWO) by using coaxial dual annular cathodes, which increases the diode current rather than the diode voltage. The reasons for the maladjustment of CRBWO under a high diode voltage are analyzed theoretically. It is found that by optimization of the diode structure, the shielding effect of the space charge of the outer beams on the inn...

  10. Design and fabrication of carbon nanotube field-emission cathode with coaxial gate and ballast resistor.

    Science.gov (United States)

    Sun, Yonghai; Yeow, John T W; Jaffray, David A

    2013-10-25

    A low density vertically aligned carbon nanotube-based field-emission cathode with a ballast resistor and coaxial gate is designed and fabricated. The ballast resistor can overcome the non-uniformity of the local field-enhancement factor at the emitter apex. The self-aligned fabrication process of the coaxial gate can avoid the effects of emitter tip misalignment and height non-uniformity. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. PSPICE simulation of bipolar pulse converter based on short-circuited coaxial transmission line

    International Nuclear Information System (INIS)

    Shi Lei; Fan Yajun

    2010-01-01

    The operating principle of the bipolar pulse converter based on short-circuited coaxial transmission line type is given. The output bipolar pulses are simulated by using PSPICE program on condition of different electric length and different impedance of the short-circuited coaxial transmission line. The bipolar pulses are generated by using unipolar pulse with pulse width of 2 ns in experiment, the experimental result fit well with the simulation result. (authors)

  12. Dark matter from split seesaw

    International Nuclear Information System (INIS)

    Kusenko, Alexander; Takahashi, Fuminobu; Yanagida, Tsutomu T.

    2010-01-01

    The seesaw mechanism in models with extra dimensions is shown to be generically consistent with a broad range of Majorana masses. The resulting democracy of scales implies that the seesaw mechanism can naturally explain the smallness of neutrino masses for an arbitrarily small right-handed neutrino mass. If the scales of the seesaw parameters are split, with two right-handed neutrinos at a high scale and one at a keV scale, one can explain the matter-antimatter asymmetry of the universe, as well as dark matter. The dark matter candidate, a sterile right-handed neutrino with mass of several keV, can account for the observed pulsar velocities and for the recent data from Chandra X-ray Observatory, which suggest the existence of a 5 keV sterile right-handed neutrino.

  13. Photon-splitting cross sections

    International Nuclear Information System (INIS)

    Johannessen, A.M.; Mork, K.J.; Overbo, I.

    1980-01-01

    The differential cross section for photon splitting (scattering of one photon into two photons) in a Coulomb field, obtained earlier by Shima, has been integrated numerically to yield various differential cross sections. Energy spectra differential with respect to the energy of one of the outgoing photons are presented for several values of the primary photon energy. Selected examples of recoil momentum distributions and some interesting doubly or multiply differential cross sections are also given. Values for the total cross section are obtained essentially for all energies. The screening effect caused by atomic electrons is also taken into account, and is found to be important for high energies, as in e + e - pair production. Comparisons with various approximate results obtained by previous authors mostly show fair agreement. We also discuss the possibilities for experimental detection and find the most promising candidate to be a measurement of both photons, and their energies, at a moderately high energy

  14. Gauge mediated mini-split

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Timothy [Institute of Theoretical Science, University of Oregon,Eugene, OR 97403 (United States); Craig, Nathaniel [Department of Physics, University of California,Santa Barbara, CA 93106 (United States); Knapen, Simon [Berkeley Center for Theoretical Physics,University of California, Berkeley, CA 94720 (United States); Theoretical Physics Group,Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2016-03-15

    We propose a simple model of split supersymmetry from gauge mediation. This model features gauginos that are parametrically a loop factor lighter than scalars, accommodates a Higgs boson mass of 125 GeV, and incorporates a simple solution to the μ−b{sub μ} problem. The gaugino mass suppression can be understood as resulting from collective symmetry breaking. Imposing collider bounds on μ and requiring viable electroweak symmetry breaking implies small a-terms and small tan β — the stop mass ranges from 10{sup 5} to 10{sup 8} GeV. In contrast with models with anomaly + gravity mediation (which also predict a one-loop loop suppression for gaugino masses), our gauge mediated scenario predicts aligned squark masses and a gravitino LSP. Gluinos, electroweakinos and Higgsinos can be accessible at the LHC and/or future colliders for a wide region of the allowed parameter space.

  15. Salt splitting with ceramic membranes

    International Nuclear Information System (INIS)

    Kurath, D.

    1996-01-01

    The purpose of this task is to develop ceramic membrane technologies for salt splitting of radioactively contaminated sodium salt solutions. This technology has the potential to reduce the low-level waste (LLW) disposal volume, the pH and sodium hydroxide content for subsequent processing steps, the sodium content of interstitial liquid in high-level waste (HLW) sludges, and provide sodium hydroxide free of aluminum for recycle within processing plants at the DOE complex. Potential deployment sites include Hanford, Savannah River, and Idaho National Engineering Laboratory (INEL). The technical approach consists of electrochemical separation of sodium ions from the salt solution using sodium (Na) Super Ion Conductors (NaSICON). As the name implies, sodium ions are transported rapidly through these ceramic crystals even at room temperatures

  16. Splitting tests on rock specimens

    Energy Technology Data Exchange (ETDEWEB)

    Davies, J D; Stagg, K G

    1970-01-01

    Splitting tests are described for a square-section sandstone specimens line loaded through steel or timber packings on the top face and supported on the bottom face either on similar packings (type A specimen) or directly on the lower platen plate of the testing machine (type B specimens). The stress distribution across the vertical central plane and the horizontal central plane were determined from a linear elastic finite element analysis for both types. Two solutions were obtained for the type B specimen: one assuming no friction between the base of the specimen and the platen plate and the other assuming no relative slip between the surfaces. Vertical and horizontal strains were measured at the center of the specimens for all loads up to failure.

  17. Split supersymmetry in unified models

    International Nuclear Information System (INIS)

    Dutta, Bhaskar; Mimura, Yukihiro

    2005-01-01

    In the context of split supersymmetry, the gaugino mass spectrum seems to be very important to satisfy the dark matter content of the universe and the gauge coupling unification. In this Letter, we have considered various sources of gaugino masses in the context of unified models. We show that the gaugino mass spectrum varies in different unification pictures. In the context of SU(5), we have found that the bino/wino mass ratio can be close to one at the weak scale which is helpful to satisfy the WMAP data. The gluino/wino mass ratio is also different from the usual scenario of unified gaugino masses. The gaugino masses can be around one TeV and m SUSY is chosen so that the gluino mass does not create any cosmological problem. In the context of the Pati-Salam model, we show that the gluino mass can be made very heavy even after maintaining the unification of the gauge couplings

  18. Spin Splitting in Different Semiconductor Quantum Wells

    International Nuclear Information System (INIS)

    Hao Yafei

    2012-01-01

    We theoretically investigate the spin splitting in four undoped asymmetric quantum wells in the absence of external electric field and magnetic field. The quantum well geometry dependence of spin splitting is studied with the Rashba and the Dresselhaus spin-orbit coupling included. The results show that the structure of quantum well plays an important role in spin splitting. The Rashba and the Dresselhaus spin splitting in four asymmetric quantum wells are quite different. The origin of the distinction is discussed in this work. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  19. Salt splitting using ceramic membranes

    Energy Technology Data Exchange (ETDEWEB)

    Kurath, D.E. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-10-01

    Many radioactive aqueous wastes in the DOE complex have high concentrations of sodium that can negatively affect waste treatment and disposal operations. Sodium can decrease the durability of waste forms such as glass and is the primary contributor to large disposal volumes. Waste treatment processes such as cesium ion exchange, sludge washing, and calcination are made less efficient and more expensive because of the high sodium concentrations. Pacific Northwest National Laboratory (PNNL) and Ceramatec Inc. (Salt Lake City UT) are developing an electrochemical salt splitting process based on inorganic ceramic sodium (Na), super-ionic conductor (NaSICON) membranes that shows promise for mitigating the impact of sodium. In this process, the waste is added to the anode compartment, and an electrical potential is applied to the cell. This drives sodium ions through the membrane, but the membrane rejects most other cations (e.g., Sr{sup +2}, Cs{sup +}). The charge balance in the anode compartment is maintained by generating H{sup +} from the electrolysis of water. The charge balance in the cathode is maintained by generating OH{sup {minus}}, either from the electrolysis of water or from oxygen and water using an oxygen cathode. The normal gaseous products of the electrolysis of water are oxygen at the anode and hydrogen at the cathode. Potentially flammable gas mixtures can be prevented by providing adequate volumes of a sweep gas, using an alternative reductant or destruction of the hydrogen as it is generated. As H{sup +} is generated in the anode compartment, the pH drops. The process may be operated with either an alkaline (pH>12) or an acidic anolyte (pH <1). The benefits of salt splitting using ceramic membranes are (1) waste volume reduction and reduced chemical procurement costs by recycling of NaOH; and (2) direct reduction of sodium in process streams, which enhances subsequent operations such as cesium ion exchange, calcination, and vitrification.

  20. Coaxial nanofibers containing TiO2 in the shell for water treatment applications

    Science.gov (United States)

    Kizildag, N.; Geltmeyer, J.; Ucar, N.; De Buysser, K.; De Clerck, K.

    2017-10-01

    In recent years, the basic electrospinning setup has undergone many modifications carried out to enhance the quality and improve the functionality of the resulting nanofibers. Being one of these modifications, coaxial electrospinning has attracted great attention. It enables to use different materials in nanofiber production and produce multi-layered and functional nanofibers in one step. In this study, TiO2 has been added to the shell layer of coaxial nanofibers to develop functional nanofibers which may be used in water treatment applications. The coaxial nanofibers containing TiO2 in the shell layer are compared to uniaxial nanofibers containing TiO2 in bulk fiber structure, regarding their morphology and photocatalytic activity. Uniform uniaxial and coaxial nanofibers with TiO2 were obtained. The average nanofiber diameter of coaxial nanofibers were higher. Coaxial nanofibers, which contained lower amount of TiO2, displayed similar performance to uniaxial nanofibers with TiO2 in terms of photocatalytic degradation ability against isoproturon.

  1. SplitDist—Calculating Split-Distances for Sets of Trees

    DEFF Research Database (Denmark)

    Mailund, T

    2004-01-01

    We present a tool for comparing a set of input trees, calculating for each pair of trees the split-distances, i.e., the number of splits in one tree not present in the other.......We present a tool for comparing a set of input trees, calculating for each pair of trees the split-distances, i.e., the number of splits in one tree not present in the other....

  2. Energy efficiency of the CTX magnetized coaxial plasma source

    International Nuclear Information System (INIS)

    Fernandez, J.C.; Barnes, C.W.; Jarboe, T.R.; Knox, S.O.; Platts, D.A.; McKenna, K.F.

    1985-01-01

    The energy efficiency of the CTX coaxial plasma source in creating spheromaks is determined experimentally to be in agreement with the theoretical prediction of lambda/sub sp//lambda/sub g/, where del x B = lambda/sub sp/ B in the spheromak, and lambda/sub g/ identical with μ 0 I/sub g//phi/sub g/ with I/sub g/ the source current and phi/sub g/ the magnetic flux through either source electrode. This is shown to be equivalent to magnetic helicity conservation. The spheromak impurity radiation was measured using an absolutely calibrated single chord bolometer system. The theoretical efficiency is within the experimental uncertainty of the ratio of spheromak radiated energy to source input energy in a group of ''dirty'' discharges. But the radiation measurement uncertainty is too large to determine whether a substantial part of the excess source energy not used in the production of spheromak magnetic energy is radiated from the spheromak volume

  3. Low temperature high frequency coaxial pulse tube for space application

    Energy Technology Data Exchange (ETDEWEB)

    Charrier, Aurelia; Charles, Ivan; Rousset, Bernard; Duval, Jean-Marc [SBT, UMR-E CEA / UJF-Grenoble 1, INAC, 17, rue des Martyrs, Grenoble, F-38054 (France); Daniel, Christophe [CNES, 18, avenue Edouard Belin, Toulouse, F-31401 (France)

    2014-01-29

    The 4K stage is a critical step for space missions. The Hershel mission is using a helium bath, which is consumed day by day (after depletion, the space mission is over) while the Plank mission is equipped with one He4 Joule-Thomson cooler. Cryogenic chain without helium bath is a challenge for space missions and 4.2K Pulse-Tube working at high frequency (around 30Hz) is one option to take it up. A low temperature Pulse-Tube would be suitable for the ESA space mission EChO (Exoplanet Characterisation Observatory, expected launch in 2022), which requires around 30mW cooling power at 6K; and for the ESA space mission ATHENA (Advanced Telescope for High ENergy Astrophysics), to pre-cool the sub-kelvin cooler (few hundreds of mW at 15K). The test bench described in this paper combines a Gifford-McMahon with a coaxial Pulse-Tube. A thermal link is joining the intercept of the Pulse-Tube and the second stage of the Gifford-McMahon. This intercept is a separator between the hot and the cold regenerators of the Pulse-Tube. The work has been focused on the cold part of this cold finger. Coupled with an active phase shifter, this Pulse-Tube has been tested and optimized and temperatures as low as 6K have been obtained at 30Hz with an intercept temperature at 20K.

  4. Experimental demonstration of plasma startup by coaxial helicity injection

    International Nuclear Information System (INIS)

    Raman, R.; Jarboe, T.R.; Nelson, B.A.; Hamp, W.T.; Izzo, V.A.; O'Neill, R.G.; Redd, A.J.; Sieck, P.E.; Smith, R.J.

    2004-01-01

    Experimental results on the transfer of a coaxial-helicity-injection (CHI) produced discharge to inductive operation are reported. CHI assisted plasma startup is more robust than inductive only operation and reduces volt-seconds consumption. After handoff to inductive operation, the initial 100 kA of CHI produced current drops to 50 kA, then ramps up to 180 kA, using only 30 mVs, about 40% higher than that produced by induction alone. Results show that initiation of CHI discharges at lower densities produce higher levels of coupling current. Coupling a CHI produced discharge to induction from a precharged central solenoid has produced record currents of 290 kA using only 52 mWb of central solenoid flux. CHI discharges can also be generated while the central transformer is in the process of being precharged, during which period it induces a negative loop voltage on the CHI discharge. These significant results were obtained on the Helicity Injected Torus-II (HIT-II) [T.R. Jarboe, Fusion Technol. 15, 7 (1989)] spherical torus experiment (major/minor radius of 0.3/0.2 m and elongation of 1.5)

  5. Coaxial magnetic brakes using single-domain YBCO

    International Nuclear Information System (INIS)

    Putman, P.T.; Salama, K.

    2008-01-01

    In coaxial magnetic brakes, the changing field produced by movement of a solenoidal magnet induces a current in the wall of a conductive tube. The interaction of the field and current leads to a repulsive force that slows the motion of the magnet. For brake applications that require high force density, melt-textured YBCO is a clear choice of material for the magnet because it can carry high currents at a given field and temperature, and is inherently capable of operating in persistent current mode. We present calculations of the performance of this type of brake as a function of magnet current density for catch tubes composed of aluminum and titanium. These results are validated with low speed (20 m/s) tests. Calculations indicate that melt-textured magnets can decelerate projectiles with a mass of 1 kg from 2000 m/s to rest in distances on the order of 10 m. This suggests that this type of brake is suitable for use in hypervelocity experiments, which sometimes requires nondestructive deceleration of projectiles for diagnostic purposes

  6. Pulse shape discrimination performance of inverted coaxial Ge detectors

    Science.gov (United States)

    Domula, A.; Hult, M.; Kermaïdic, Y.; Marissens, G.; Schwingenheuer, B.; Wester, T.; Zuber, K.

    2018-05-01

    We report on the characterization of two inverted coaxial Ge detectors in the context of being employed in future 76Ge neutrinoless double beta (0 νββ) decay experiments. It is an advantage that such detectors can be produced with bigger Ge mass as compared to the planar Broad Energy Ge (BEGe) or p-type Point Contact (PPC) detectors that are currently used in the GERDA and MAJORANA DEMONSTRATOR 0 νββ decay experiments respectively. This will result in a lower background for the search of 0 νββ decay due to a reduction of detector surface to volume ratio, cables, electronics and holders which are dominating nearby radioactive sources. The measured resolution near the 76Ge Q-value at 2039 keV is 2.3 keV FWHM and their pulse-shape discrimination of background events are similar to BEGe and PPC detectors. It is concluded that this type of Ge-detector is suitable for usage in 76Ge 0 νββ decay experiments.

  7. Plasma Sheath Behavior in a Coaxial Discharge Device

    International Nuclear Information System (INIS)

    EL-Aragi, G.; Soliman, H.M.; Masoud, M.M.

    2001-01-01

    The behavior of the plasma sheath has been studied experimentally and theoretically for 3 kJ coaxial discharge device. The discharge takes place in argon gas with pressure of 0.8 mbar. The experiments are conducted with a 10 kV bank charging voltage, which corresponds to 110 kA peak discharge current with time period of 34 μs. The experimental investigations have been studied using a magnetic probes and a miniature Rogowsky coil. A snowplough model is used to drive an analytical solution of the plasma sheath behavior in axial direction. Measurements of radial distribution of plasma sheath current density J r at the muzzle, show that J r has the following relation, J r is proportional to r -1.1 . From the experimental results and theoretical calculations of axial distribution of azimuthal magnetic field induction and plasma sheath velocity, the inclination angle between the normal of the plasma sheath with the axial distance at any axial position is evaluated and it has approximately a constant value for most axial distances. Also, the axial motion of plasma sheath acceleration is estimated experimentally a max = 0.13 x 10 12 ' cm / s 2 at z = 11 cm and from theoretical calculations a max = 0.15 x 10 12 cm/ s 2 at max z = 1.6 cm. A comparison of the experimental results with the theoretical calculations, under the assumption of the snowplough model are not in agreement. (author)

  8. Motion and shape of snowplough sheets in coaxial accelerators

    International Nuclear Information System (INIS)

    Tsagas, N.F.; Mair, G.L.R.; Prinn, A.E.

    1978-01-01

    A long coaxial accelerator is filled with helium at initial gas pressure between 0.2 and 4 Torr. When connected to a large capacitor at < - 10 kV a discharge is started at one end; the central electrode has negative polarity. The velocity of the plasma sheet, the snowplough, and its shape have been derived from streak photographs for terminal currents between about 100 and 300 kA. The motion of the sheet has been analysed by balancing the electromagnetic driving force against the inertia of the mass of the gas swept up by a plane sheet taken to be impenetrable to gas atoms. The calculated positions and average sheet velocities, which involve simplifying assumptions, have been found to be in good agreement with observations at different positions and pressures. Also the shape of the sheet has been derived by allowing for the sheet's curvature in the linear momentum equation while net radial motions causing variations in profile have, at first, been excluded. The calculated shape of the sheet is very nearly that photographically observed. The axial velocity of a sheet element is evaluated under the assumption that the plasma is azimuthally uniform, free of spikes and that the vessel's wall does not affect the shape. (author)

  9. Characteristics of Oscillating Flames in a Coaxial Confined Jet

    Directory of Open Access Journals (Sweden)

    Min Suk Cha

    2010-12-01

    Full Text Available Flame characteristics when a non-premixed n-butane jet is ejected into a coaxial cylindrical tube are investigated experimentally. Flame stability depends mainly on the characteristics of flame propagation as well as air entrainment which depend on the jet momentum and on the distance between the nozzle exit and the base of a confined tube. As flow rate increases, the flame lifts off from a nozzle attached diffusion flame and a stationary lifted flame can be stabilized. The liftoff height increases nearly linearly with the average velocity at the nozzle exit. The lifted flame has a tribrachial flame structure, which consists of a rich premixed flame, a lean premixed flame, and a diffusion flame, all extending from a single location. As flow rate further increases, periodically oscillating flames are observed inside the confined tube. Once flame oscillation occurs, the flame undergoes relatively stable oscillation such that it has nearly constant oscillation amplitude and frequency. The criteria of flame oscillation are mapped as functions of nozzle diameter, the distance between nozzle and tube, and jet velocity. This type of flame oscillation can be characterized by Strouhal number in terms of flame oscillation amplitude, frequency, and jet velocity. Buoyancy driven flame oscillation which is one of the viable mechanism for flame oscillation is modeled and the results agrees qualitatively with experimental results, suggesting that the oscillation is due to periodic blowoff and flashback under the influence of buoyancy.

  10. Research of Driving Circuit in Coaxial Induction Coilgun

    Directory of Open Access Journals (Sweden)

    Yadong Zhang

    2013-09-01

    Full Text Available Power supply is crucial equipment in coaxial induction coil launcher.Configuration of the driving circuit influences the efficiency of the coil launcher directly.This paper gives a detailed analysis of the properties of the driving circuit construction based on the capacitor source. Three topologies of the driving circuit are compared including oscillation circuit, crowbar circuit and half-wave circuit. It is proved that which circuit has the better efficiency depends on the detailed parameters of the experiment, especially the crowbar resistance. Crowbar resistor regulates not only efficiency of the system, but also temperature rise of the coil. Electromagnetic force (EMF applied on the armature will be another question which influences service condition of the driving circuits. Oscillation circuit and crowbar circuit should apply to the asynchronous induction coil launcher and synchronous induction coil launcher, respectively. Half-wave circuit is seldom used in the experiment. Although efficiency of the half-wave circuit is very high, the speed of the armature is low. A simple independent half-wave circuit is suggested in this paper. Generally speaking, the comprehensive property of crowbar circuit is the most practical in the three typical circuits. Conclusions of the paper could provide guidelines for practice.

  11. Quasi-optical mode converter for a coaxial cavity gyrotron

    International Nuclear Information System (INIS)

    Jin, J.

    2007-03-01

    This work concentrates on the synthesis of the quasioptical mode converter for the 170 GHz, TE 34,19 -mode, 2MW, CW coaxial-cavity gyrotron at Forschungszentrum Karlsruhe (FZK). The improvement of the general method for the design of so-call dimpled-wall launcher to provide a good Gaussian mode content is described. This method is verified through the design of a launcher operating in the TE 22,6 mode at 118 GHz. A phase rule is proposed as a quality criterion for monitoring the optimization and the choices of parameters of the quasi-optical mode converter. High-order harmonics introduced to the launcher wall deformations are proposed for this gyrotron. The launcher is numerically optimized, the fields on the cut edges are suppressed. The fields in the launcher are well approximated by the waveguide modes, the radiated fields are calculated using the scalar diffraction integral. The procedure for the numerical optimization of the mirror system is improved, the tolerance conditions of the phase correcting mirrors are investigated. A conversion efficiency of 95.8% to the circular fundamental Gaussian distribution with 20mm beam waist and power transmission of 90% are achieved in the window plane using the optimized quasi-optical mode converter. The methods to ameliorate the initial conditions of the phase correcting mirrors are explored. (orig.)

  12. Standard Model Particles from Split Octonions

    Directory of Open Access Journals (Sweden)

    Gogberashvili M.

    2016-01-01

    Full Text Available We model physical signals using elements of the algebra of split octonions over the field of real numbers. Elementary particles are corresponded to the special elements of the algebra that nullify octonionic norms (zero divisors. It is shown that the standard model particle spectrum naturally follows from the classification of the independent primitive zero divisors of split octonions.

  13. Cheating More when the Spoils Are Split

    Science.gov (United States)

    Wiltermuth, Scott S.

    2011-01-01

    Four experiments demonstrated that people are more likely to cheat when the benefits of doing so are split with another person, even an anonymous stranger, than when the actor alone captures all of the benefits. In three of the studies, splitting the benefits of over-reporting one's performance on a task made such over-reporting seem less…

  14. Split Scheduling with Uniform Setup Times

    NARCIS (Netherlands)

    Schalekamp, F.; Sitters, R.A.; van der Ster, S.L.; Stougie, L.; Verdugo, V.; van Zuylen, A.

    2015-01-01

    We study a scheduling problem in which jobs may be split into parts, where the parts of a split job may be processed simultaneously on more than one machine. Each part of a job requires a setup time, however, on the machine where the job part is processed. During setup, a machine cannot process or

  15. Split scheduling with uniform setup times.

    NARCIS (Netherlands)

    F. Schalekamp; R.A. Sitters (René); S.L. van der Ster; L. Stougie (Leen); V. Verdugo; A. van Zuylen

    2015-01-01

    htmlabstractWe study a scheduling problem in which jobs may be split into parts, where the parts of a split job may be processed simultaneously on more than one machine. Each part of a job requires a setup time, however, on the machine where the job part is processed. During setup, a

  16. Particulate photocatalysts for overall water splitting

    Science.gov (United States)

    Chen, Shanshan; Takata, Tsuyoshi; Domen, Kazunari

    2017-10-01

    The conversion of solar energy to chemical energy is a promising way of generating renewable energy. Hydrogen production by means of water splitting over semiconductor photocatalysts is a simple, cost-effective approach to large-scale solar hydrogen synthesis. Since the discovery of the Honda-Fujishima effect, considerable progress has been made in this field, and numerous photocatalytic materials and water-splitting systems have been developed. In this Review, we summarize existing water-splitting systems based on particulate photocatalysts, focusing on the main components: light-harvesting semiconductors and co-catalysts. The essential design principles of the materials employed for overall water-splitting systems based on one-step and two-step photoexcitation are also discussed, concentrating on three elementary processes: photoabsorption, charge transfer and surface catalytic reactions. Finally, we outline challenges and potential advances associated with solar water splitting by particulate photocatalysts for future commercial applications.

  17. Morphological appearances and photo-controllable coloration of dye-doped cholesteric liquid crystal/polymer coaxial microfibers fabricated by coaxial electrospinning technique.

    Science.gov (United States)

    Lin, Jia-De; Chen, Che-Pei; Chen, Lin-Jer; Chuang, Yu-Chou; Huang, Shuan-Yu; Lee, Chia-Rong

    2016-02-08

    This study systematically investigates the morphological appearance of azo-chiral dye-doped cholesteric liquid crystal (DDCLC)/polymer coaxial microfibers obtained through the coaxial electrospinning technique and examines, for the first time, their photocontrollable reflection characteristics. Experimental results show that the quasi-continuous electrospun microfibers can be successfully fabricated at a high polymer concentration of 17.5 wt% and an optimum ratio of 2 for the feeding rates of sheath to core materials at 25 °C and a high humidity of 50% ± 2% in the spinning chamber. Furthermore, the optical controllability of the reflective features for the electrospun fibers is studied in detail by changing the concentration of the azo-chiral dopant in the core material, the UV irradiation intensity, and the core diameter of the fibers. Relevant mechanisms are addressed to explain the optical-control behaviors of the DDCLC coaxial fibers. Considering the results, optically controllable DDCLC coaxial microfibers present potential applications in UV microsensors and wearable smart textiles or swabs.

  18. Fast Plasma from a Coaxial Gun; Plasma Rapide Produit par un Canon Coaxial; Bystraya plazma iz koaksial'nogo inzhektora; Produccion de Plasma Rapido Mediante un Inyector Coaxial

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, J.; Henins, I. [Los Alamos Scientific Laboratory, Los Alamos, NM (United States)

    1966-04-15

    The coaxial gun in use here is a source or two different plasmas produced by separate mechanisms. Abundant slow ( Tilde-Operator 10{sup 7} cm/sec) deuterium plasma is produced directly by the j x B interaction of the radial plasma current and the magnetic field of the feed current along the centre electrode. The current disturbance moves through the injected gas toward the gun muzzle at Tilde-Operator 2.5 x 10{sup 7} cm/sec, storing energy behind it in magnetic field and plasma motion. The gun, with its stored energy, functions as a high power low impedance electrical generator to drive into the vacuum beyond the gun muzzle a jet of current which is the source of the fast plasma ( Tilde-Operator 5 x 10{sup 17} deuterons, Tilde-Operator 10{sup 8} cm/sec). The current jet and the plasma it produces are the subjects of these experiments. The mechanism of acceleration is complicated and imperfectly understood, but considerable insight has been gained by an extensive series of experiments, using as diagnostics the following: external diamagnetic pickup loops, intra vacuo Rogowsky loops, electric probes, external capacitive pickup electrodes, magnetic and electrostatic particle deflection analysis, spectroscopy, target light photography, time of flight with and without a guide field, d-d neutrons from the plasma volume and other methods. The picture which emerges is one of a complicated magneto-electric process taking place in front of the gun muzzle. The acceleration process depends on low gas density there as contrasted'with high density inside the gun. The fast plasma is largely derived from gas adsorbed on the electrodes. This makes necessary a clean vacuum so as to avoid contamination with highly ionized fast impurity ions (C{sup 5+}, 10{sup 8} cm/sec). Electrode material evaporates but appears not to be a serious contaminant because it comes late. The high voltage actually accelerating the ions is associated with the rapid expansion into vacuum of a magnetic flux

  19. Split-coil-system SULTAN

    International Nuclear Information System (INIS)

    Vecsey, G.

    1992-08-01

    The high field superconductor test facility SULTAN started operation successfully in May 1992. Originally designed for testing full scale conductors for the large magnets of the next generation fusion reactors, the SULTAN facility installed at PSI (Switzerland) was designed as a common venture of three European Laboratories: ENEA (Italy), ECN (Netherlands) and PSI, and built by ENEA and PSI in the framework of the Euratom Fusion Technology Program. Presently the largest facility in the world, with its superconducting split coil system generating 11 Tesla in a 0.6 m bore, it is ready now for testing superconductor samples with currents up to 50 kA at variable cooling conditions. Similar tests can be arranged also for other applications. SULTAN is offered by the European Community as a contribution to the worldwide cooperation for the next step of fusion reactor development ITER. First measurements on conductor developed by CEA (Cadarache) are now in progress. Others like those of ENEA and CERN will follow. For 1993, a test of an Italian 12 TZ model coil for fusion application is planned. SULTAN is a worldwide unique facility marking the competitive presence of Swiss technology in the field of applied superconductivity research. Based on development and design of PSI, the high field Nb 3 Sn superconductors and coils were fabricated at the works of Kabelwerke Brugg and ABB, numerous Swiss companies contributed to the success of this international effort. Financing of the Swiss contribution of SULTAN was made available by NEFF, BEW, BBW, PSI and EURATOM. (author) figs., tabs., 20 refs

  20. Coaxial two-channel high-gradient dielectric wakefield accelerator

    Directory of Open Access Journals (Sweden)

    G. V. Sotnikov

    2009-06-01

    Full Text Available A new scheme for a dielectric wakefield accelerator is proposed that employs a cylindrical multizone dielectric structure configured as two concentric dielectric tubes with outer and inner vacuum channels for drive and accelerated bunches. Analytical and numerical studies have been carried out for such coaxial dielectric-loaded structures (CDS for high-gradient acceleration. An analytical theory of wakefield excitation by particle bunches in a multizone CDS has been formulated. Numerical calculations are presented for an example of a CDS using dielectric tubes with dielectric permittivity 5.7, having external diameters of 2.121 and 0.179 mm with inner diameters of 2.095 and 0.1 mm. An annular 5 GeV, 6 nC electron bunch with rms length of 0.035 mm energizes a wakefield on the structure axis having an accelerating gradient of ∼600  MeV/m with a transformer ratio ∼8∶1. The period of the accelerating field is ∼0.33  mm. If the width of the drive bunch channel is decreased, it is possible to obtain an accelerating gradient of >1  GeV/m while keeping the transformer ratio approximately the same. Full numerical simulations using a particle-in-cell code have confirmed results of the linear theory and furthermore have shown the important influence of the quenching wave that restricts the region of the wakefield to within several periods following the drive bunch. Numerical simulations for another example have shown nearly stable transport of drive and accelerated bunches through the CDS, using a short train of drive bunches.

  1. Timing of gamma rays in coaxial germanium detector systems

    International Nuclear Information System (INIS)

    El-Ibiary, M.Y.

    1979-01-01

    A study is reported on the timing uncertainty in gamma ray coaxial germanium detector systems. The work deals with the zero cross over method which is widely used to reduce the dependence of the instant of timing on the radiation energy absorbed and on the position within the detector at which absorption takes place. It is found that the amplitude risetime compensated (ARC) method gives, under normal conditions, the best resolution at a specific energy. For higher energies, the resolution improves and there is no shift of the mean instant of timing. The method is therefore well suited for wide energy coverage. The parameters involved in implementing an ARC system for optimum performance at a specific energy are identified in terms of the preamplifier noise level and risetime. A trade off can be made between the resolutions at high and at low energies. The time resolution attained is given by means of a series of charts which use normalized dimensionless variables for ready application to any given case. Lithium compensated Ge detectors which normally operate under conditions of velocity saturation of the charge carriers by applying sufficient bias voltage create an electric field in excess of 1 kV/cm throughout the depleted region. High purity Ge detectors where velocity saturation may not be reached within certain parts of the depleted region are studied. Special attention is given to the probability of pulses being incorrectly timed because of their slow rise or small magnitude. Such incorrect timing is energy-dependent and results in a noticeable distortion of the timing spectrum that relates to a wide energy range. Limitations on system parameters to keep the probability of incorrect timing below a specified fraction are given

  2. Dynamics of two coaxial cylindrical shells containing viscous fluid

    International Nuclear Information System (INIS)

    Yeh, T.T.; Chen, S.S.

    1976-09-01

    This study was motivated by the need to design the thermal shield in reactor internals and other system components to avoid detrimental flow-induced vibrations. The system component is modeled as two coaxial shells separated by a viscous fluid. In the analysis, Flugge's shell equations of motion and linearized Navier-Stokes equation for viscous fluid are employed. First, a traveling-wave type solution is taken for shells and fluid. Then, from the interface conditions between the shells and fluid, the solution for the fluid medium is expressed in terms of shell displacements. Finally, using the shell equations of motion gives the frequency equation, from which the natural frequency, mode shape, and modal damping ratio of coupled modes can be calculated. The analytical results show a fairly good qualitative agreement with the published experimental data. Some important conclusions are as follows: (1) In computing the natural frequencies and mode shapes of uncoupled modes and coupled modes, the fluid may be considered inviscid and incompressible. (2) There exists out-of-phase and in-phase modes. The lowest natural frequency is always associated with the out-of-phase mode. (3) The lowest natural frequency of coupled modes is lower than the uncoupled modes. (4) The fluid viscosity contributes significantly to damping, in particular, the modal damping of the out-of-phase modes isrelatively large for small gaps. (5) If the fluid gap is small, or the fluid viscosity is relatively high, the simulation of the vibration Reynolds number should be included to ensure that modal damping of the model is properly accounted for. With the presented analysis and results, the frequency and damping characteristics can be analyzed and design parameters can be related to frequency and damping

  3. Investigation of multipactor breakdown in communication satellite microwave co-axial systems

    Science.gov (United States)

    Nagesh, S. K.; Revannasiddiah, D.; Shastry, S. V. K.

    2005-01-01

    Multipactor breakdown or multipactor discharge is a form of high frequency discharge that may occur in microwave components operating at very low pressures. Some RF components of multi-channel communication satellites have co-axial geometry and handle high RF power under near-vacuum conditions. The breakdown occurs due to secondary electron resonance, wherein electrons move back and forth in synchronism with the RF voltage across the gap between the inner and outer conductors of the co-axial structure. If the yield of secondary electrons from the walls of the co-axial structure is greater than unity, then the electron density increases with time and eventually leads to the breakdown. In this paper, the current due to the oscillating electrons in the co-axial geometry has been treated as a radially oriented Hertzian dipole. The electric field, due to this dipole, at any point in the coaxial structure, may then be determined by employing the dyadic Green's function technique. This field has been compared with the field that would exist in the absence of multipactor.

  4. Optimization and analysis of shape of coaxial electrode for microwave plasma in water

    International Nuclear Information System (INIS)

    Hattori, Yoshiaki; Mukasa, Shinobu; Nomura, Shinfuku; Toyota, Hiromichi

    2010-01-01

    The effect of the shape of the electrode to generate 2.45 GHz microwave plasma in pure water is examined. Three variations of a common coaxial electrode are proposed, and compared according to the power required for plasma ignition and the position of plasma ignition in pure water at 6 kPa using a high-speed camera. These coaxial electrodes are calculated using three-dimensional finite-difference time-domain method calculations. The superior shape of coaxial electrode is found to be one with a flat plane on the tip of the inner electrode and dielectric substance located below the tip of the outer electrode. The position of the plasma ignition is related to the shape of the coaxial electrode. By solving the heat-conduction equation of water around the coaxial electrode taking into account the absorption of the microwave energy, the position of the plasma ignition is found to be not where electric field is the largest, but rather where temperature is maximized.

  5. The Co-axial Flow of Injectable Solid Hydrogels with Encapsulated Cells

    Science.gov (United States)

    Stewart, Brandon; Pochan, Darrin; Sathaye, Sameer

    2013-03-01

    Hydrogels are quickly becoming an important biomaterial that can be used for the safe, localized injection of cancer drugs, the injection of stem cells into areas of interest or other biological applications. Our peptides can be self-assembled in a syringe where they form a gel, sheared by injection and, once in the body, immediately reform a localized pocket of stiff gel. My project has been designed around looking at the possibility of having a co-axial strand, in which one gel can surround another. This co-axial flow can be used to change the physical properties of our gel during injection, such as stiffening our gel using hyaluronic acid or encapsulating cells in the gel and surrounding the gel with growth medium or other biological factors. Rheology on hyaluron stiffened gels and cells encapsulated in gels was performed for comparison to the results from co-axial flow. Confocal microscopy was used to examine the coaxial gels after flow and to determine how the co-axial nature of the gels is affected by the concentration of peptide.

  6. Theoretical analysis to investigate thermal performance of co-axial heat pipe solar collector

    Energy Technology Data Exchange (ETDEWEB)

    Azad, E. [Iranian Research Organization for Science and Technology (IROST), Advanced Materials and Renewable Energy Department, Tehran (Iran, Islamic Republic of)

    2011-12-15

    The thermal performance of co-axial heat pipe solar collector which consist of a collector 15 co-axial heat pipes surrounded by a transparent envelope and which heat a fluid flowing through the condenser tubes have been predicted using heat transfer analytical methods. The analysis considers conductive and convective losses and energy transferred to a fluid flowing through the collector condenser tubes. The thermal performances of co-axial heat pipe solar collector is developed and are used to determine the collector efficiency, which is defined as the ratio of heat taken from the water flowing in the condenser tube and the solar radiation striking the collector absorber. The theoretical water outlet temperature and efficiency are compared with experimental results and it shows good agreement between them. The main advantage of this collector is that inclination of collector does not have influence on performance of co-axial heat pipe solar collector therefore it can be positioned at any angle from horizontal to vertical. In high building where the roof area is not enough the co-axial heat pipe solar collectors can be installed on the roof as well as wall of the building. The other advantage is each heat pipe can be topologically disconnected from the manifold. (orig.)

  7. A nonlinear theory of relativistic klystrons connected to a coaxial waveguide

    International Nuclear Information System (INIS)

    Uhm, H.S.; Hendricks, K.J.; Arman, M.J.; Bowers, L.; Hackett, K.E.; Spencer, T.A.; Coleman, P.D.; Lemke, R.W.

    1997-01-01

    A self-consistent nonlinear theory of current modulation in an electron beam propagating through relativistic klystrons connected to a coaxial waveguide is developed. A theoretical model of the beam-energy increase Δγ near the extraction cavity is also developed, based on the self-potential depression. The potential depression κ can be significantly reduced in the vicinity of the extraction cavity from its value at the injection point. In appropriate system parameters, the kinetic-energy increase can easily be more than 50 keV, thereby eliminating the possibility of virtual cathode in the extraction cavity. Properties of the current modulation in a klystron are also investigated, assuming that a regular cylindrical waveguide is connected to a coaxial waveguide at the propagation distance z=z 1 . Due to proximity of a grounded conductor, the beam close-quote s potential depression κ in the coaxial region is considerably less than that in the regular region. It is shown in the present analysis that amplitude of the current modulation increases drastically as the coaxial inner-conductor approaches the driving cavity. Moreover, the amplitude of the current modulation in the coaxial region changes slowly in comparison with that in the regular region

  8. A novel coaxial nozzle for in-process adjustment of electrospun scaffolds’ fiber diameter

    Directory of Open Access Journals (Sweden)

    Becker A.

    2015-09-01

    Full Text Available Electrospinning is a versatile method of producing micro- and nanofibers deposited in mats used as scaffolds for tissue engineering. Depending on the application, single or coaxial electrospinning can be used. Coaxial electrospinning enables the use of a broad spectrum of materials, the fabrication of hollow or core/shell fibers and an automatisation of the entire electrospinning process. In this regard, the design of coaxial nozzles plays a major role in a standardized as well as tailor-made scaffold fabrication. For this purpose an optimised coaxial nozzle has been designed and fabricated. Furthermore, tests have been carried out to validate the new nozzle design. With the use of the costum-made nozzle polymer concentration could be varied in a gradual manner. The variation in polymer concentration lead to fiber diameters between 0.75 to 3.25 μm. In addition, an increase in rotating velocity lead to an increase in fiber alignment as well as a slight decrease in fiber diameter. The demonstrated modifications of coaxial electrospinning proved to be a powerful tool for in-process adjustments of scaffold fabrication.

  9. Theoretical analysis to investigate thermal performance of co-axial heat pipe solar collector

    Science.gov (United States)

    Azad, E.

    2011-12-01

    The thermal performance of co-axial heat pipe solar collector which consist of a collector 15 co-axial heat pipes surrounded by a transparent envelope and which heat a fluid flowing through the condenser tubes have been predicted using heat transfer analytical methods. The analysis considers conductive and convective losses and energy transferred to a fluid flowing through the collector condenser tubes. The thermal performances of co-axial heat pipe solar collector is developed and are used to determine the collector efficiency, which is defined as the ratio of heat taken from the water flowing in the condenser tube and the solar radiation striking the collector absorber. The theoretical water outlet temperature and efficiency are compared with experimental results and it shows good agreement between them. The main advantage of this collector is that inclination of collector does not have influence on performance of co-axial heat pipe solar collector therefore it can be positioned at any angle from horizontal to vertical. In high building where the roof area is not enough the co-axial heat pipe solar collectors can be installed on the roof as well as wall of the building. The other advantage is each heat pipe can be topologically disconnected from the manifold.

  10. Fabrication and application of coaxial polyvinyl alcohol/chitosan nanofiber membranes

    Directory of Open Access Journals (Sweden)

    Kuo Ting-Yun

    2017-12-01

    Full Text Available It is difficult to fabricate chitosan-wrapped coaxial nanofibers, because highly viscous chitosan solutions might hinder the manufacturing process. To overcome this difficulty, our newly developed method, which included the addition of a small amount of gum arabic, was utilized to prepare much less viscous chitosan solutions. In this way, coaxial polyvinyl alcohol (PVA/chitosan (as core/shell nanofiber membranes were fabricated successfully by coaxial electrospinning. The core/shell structures were confirmed by TEM, and the existence of PVA and chitosan was also verified using FT-IR and TGA. The tensile strength of the nanofiber membranes was increased from 0.6-0.7 MPa to 0.8-0.9 MPa after being crosslinked with glutaraldehyde. The application potential of the PVA/chitosan nanofiber membranes was tested in drug release experiments by loading the core (PVA with theophylline as a model drug. The use of the coaxial PVA/chitosan nanofiber membranes in drug release extended the release time of theophylline from 5 minutes to 24 hours. Further, the release mechanisms could be described by the Korsmeyer-Peppas model. In summary, by combining the advantages of PVA and chitosan (good mechanical strength and good biocompatibility respectively, the coaxial PVA/chitosan nanofiber membranes are potential biomaterials for various biomedical applications.

  11. Experimental design and instability analysis of coaxial electrospray process for microencapsulation of drugs and imaging agents.

    Science.gov (United States)

    Si, Ting; Zhang, Leilei; Li, Guangbin; Roberts, Cynthia J; Yin, Xiezhen; Xu, Ronald

    2013-07-01

    Recent developments in multimodal imaging and image-guided therapy requires multilayered microparticles that encapsulate several imaging and therapeutic agents in the same carrier. However, commonly used microencapsulation processes have multiple limitations such as low encapsulation efficiency and loss of bioactivity for the encapsulated biological cargos. To overcome these limitations, we have carried out both experimental and theoretical studies on coaxial electrospray of multilayered microparticles. On the experimental side, an improved coaxial electrospray setup has been developed. A customized coaxial needle assembly combined with two ring electrodes has been used to enhance the stability of the cone and widen the process parameter range of the stable cone-jet mode. With this assembly, we have obtained poly(lactide-co-glycolide) microparticles with fine morphology and uniform size distribution. On the theoretical side, an instability analysis of the coaxial electrified jet has been performed based on the experimental parameters. The effects of process parameters on the formation of different unstable modes have been studied. The reported experimental and theoretical research represents a significant step toward quantitative control and optimization of the coaxial electrospray process for microencapsulation of multiple drugs and imaging agents in multimodal imaging and image-guided therapy.

  12. Communication: Tunnelling splitting in the phosphine molecule

    Science.gov (United States)

    Sousa-Silva, Clara; Tennyson, Jonathan; Yurchenko, Sergey N.

    2016-09-01

    Splitting due to tunnelling via the potential energy barrier has played a significant role in the study of molecular spectra since the early days of spectroscopy. The observation of the ammonia doublet led to attempts to find a phosphine analogous, but these have so far failed due to its considerably higher barrier. Full dimensional, variational nuclear motion calculations are used to predict splittings as a function of excitation energy. Simulated spectra suggest that such splittings should be observable in the near infrared via overtones of the ν2 bending mode starting with 4ν2.

  13. Communication: Tunnelling splitting in the phosphine molecule

    Energy Technology Data Exchange (ETDEWEB)

    Sousa-Silva, Clara; Tennyson, Jonathan; Yurchenko, Sergey N. [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom)

    2016-09-07

    Splitting due to tunnelling via the potential energy barrier has played a significant role in the study of molecular spectra since the early days of spectroscopy. The observation of the ammonia doublet led to attempts to find a phosphine analogous, but these have so far failed due to its considerably higher barrier. Full dimensional, variational nuclear motion calculations are used to predict splittings as a function of excitation energy. Simulated spectra suggest that such splittings should be observable in the near infrared via overtones of the ν{sub 2} bending mode starting with 4ν{sub 2}.

  14. Tensor products of higher almost split sequences

    OpenAIRE

    Pasquali, Andrea

    2015-01-01

    We investigate how the higher almost split sequences over a tensor product of algebras are related to those over each factor. Herschend and Iyama gave a precise criterion for when the tensor product of an $n$-representation finite algebra and an $m$-representation finite algebra is $(n+m)$-representation finite. In this case we give a complete description of the higher almost split sequences over the tensor product by expressing every higher almost split sequence as the mapping cone of a suit...

  15. Semi-strong split domination in graphs

    Directory of Open Access Journals (Sweden)

    Anwar Alwardi

    2014-06-01

    Full Text Available Given a graph $G = (V,E$, a dominating set $D subseteq V$ is called a semi-strong split dominating set of $G$ if $|V setminus D| geq 1$ and the maximum degree of the subgraph induced by $V setminus D$ is 1. The minimum cardinality of a semi-strong split dominating set (SSSDS of G is the semi-strong split domination number of G, denoted $gamma_{sss}(G$. In this work, we introduce the concept and prove several results regarding it.

  16. Splitting Functions at High Transverse Momentum

    CERN Document Server

    Moutafis, Rhea Penelope; CERN. Geneva. TH Department

    2017-01-01

    Among the production channels of the Higgs boson one contribution could become significant at high transverse momentum which is the radiation of a Higgs boson from another particle. This note focuses on the calculation of splitting functions and cross sections of such processes. The calculation is first carried out on the example $e\\rightarrow e\\gamma$ to illustrate the way splitting functions are calculated. Then the splitting function of $e\\rightarrow eh$ is calculated in similar fashion. This procedure can easily be generalized to processes such as $q\\rightarrow qh$ or $g\\rightarrow gh$.

  17. Splitting Strip Detector Clusters in Dense Environments

    CERN Document Server

    Nachman, Benjamin Philip; The ATLAS collaboration

    2018-01-01

    Tracking in high density environments, particularly in high energy jets, plays an important role in many physics analyses at the LHC. In such environments, there is significant degradation of track reconstruction performance. Between runs 1 and 2, ATLAS implemented an algorithm that splits pixel clusters originating from multiple charged particles, using charge information, resulting in the recovery of much of the lost efficiency. However, no attempt was made in prior work to split merged clusters in the Semi Conductor Tracker (SCT), which does not measure charge information. In spite of the lack of charge information in SCT, a cluster-splitting algorithm has been developed in this work. It is based primarily on the difference between the observed cluster width and the expected cluster width, which is derived from track incidence angle. The performance of this algorithm is found to be competitive with the existing pixel cluster splitting based on track information.

  18. Baryons electromagnetic mass splittings in potential models

    International Nuclear Information System (INIS)

    Genovese, M.; Richard, J.-M.; Silvestre-Brac, B.; Varga, K.

    1998-01-01

    We study electromagnetic mass splittings of charmed baryons. We point out discrepancies among theoretical predictions in non-relativistic potential models; none of these predictions seems supported by experimental data. A new calculation is presented

  19. Pneumothorax Complicating Coaxial and Non-coaxial CT-Guided Lung Biopsy: Comparative Analysis of Determining Risk Factors and Management of Pneumothorax in a Retrospective Review of 650 Patients.

    Science.gov (United States)

    Nour-Eldin, Nour-Eldin A; Alsubhi, Mohammed; Emam, Ahmed; Lehnert, Thomas; Beeres, Martin; Jacobi, Volkmar; Gruber-Rouh, Tatjana; Scholtz, Jan-Erik; Vogl, Thomas J; Naguib, Nagy N

    2016-02-01

    To assess the scope and determining risk factors related to the development of pneumothorax throughout CT-guided biopsy of pulmonary lesions in coaxial and non-coaxial techniques and the outcome of its management. The study included CT-guided percutaneous lung biopsies in 650 consecutive patients (407 males, 243 females; mean age 54.6 years, SD 5.2) from November 2008 to June 2013 in a retrospective design. Patients were classified according to lung biopsy technique into coaxial group (318 lesions) and non-coaxial group (332 lesions). Exclusion criteria for biopsy were lesions pneumothorax were classified into: (a) Technical risk factors, (b) patient-related risk factors, and (c) lesion-associated risk factors. Radiological assessments were performed by two radiologists in consensus. Mann-Whitney U test and Fisher's exact tests were used for statistical analysis. p values pneumothorax complicating CT-guided lung biopsy was less in the non-coaxial group (23.2 %, 77 out of 332) than the coaxial group (27 %, 86 out of 318). However, the difference in incidence between both groups was statistically insignificant (p = 0.14). Significant risk factors for the development of pneumothorax in both groups were emphysema (p pneumothorax in the non-coaxial group was significantly correlated to the number of specimens obtained (p = 0.006). This factor was statistically insignificant in the coaxial group (p = 0.45). The biopsy yield was more diagnostic and conclusive in the coaxial group in comparison to the non-coaxial group (p = 0.008). Simultaneous incidence of pneumothorax and pulmonary hemorrhage was 27.3 % (21/77) in non-coaxial group and in 30.2 % (26/86) in coaxial group. Conservative management was sufficient for treatment of 91 out of 101 patients of pneumothorax in both groups (90.1 %). Manual evacuation of pneumothorax was efficient in 44/51 patients (86.3 %) in both groups and intercostal chest tube was applied after failure of manual evacuation (7

  20. Collapsed polymer-directed synthesis of multicomponent coaxial-like nanostructures

    KAUST Repository

    Huang, Zhiqi; Liu, Yijing; Zhang, Qian; Chang, Xiaoxia; Li, Ang; Deng, Lin; Yi, Chenglin; Yang, Yang; Khashab, Niveen M.; Gong, Jinlong; Nie, Zhihong

    2016-01-01

    Multicomponent colloidal nanostructures (MCNs) exhibit intriguing topologically dependent chemical and physical properties. However, there remain significant challenges in the synthesis of MCNs with high-order complexity. Here we show the development of a general yet scalable approach for the rational design and synthesis of MCNs with unique coaxial-like construction. The site-preferential growth in this synthesis relies on the selective protection of seed nanoparticle surfaces with locally defined domains of collapsed polymers. By using this approach, we produce a gallery of coaxial-like MCNs comprising a shaped Au core surrounded by a tubular metal or metal oxide shell. This synthesis is robust and not prone to variations in kinetic factors of the synthetic process. The essential role of collapsed polymers in achieving anisotropic growth makes our approach fundamentally distinct from others. We further demonstrate that this coaxial-like construction can lead to excellent photocatalytic performance over conventional core–shell-type MCNs.

  1. A Numerical Study on Heat Transfer and Flow Characteristics of a Finned Downhole Coaxial Heat Exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chun Dong; Lee, Dong Hyun; Park, Byung-Sik; Choi, Jaejoon [Korea Institute of Energy Research (KIER), Daejeon (Korea, Republic of)

    2017-02-15

    In this study, the flow and heat transfer characteristics of the finned annular passage were investigated numerically. The annular passage simulates co-axial geothermal heat exchanger, and fins are installed on its inner wall to reduce heat loss from the production passage (annulus) to injection passage (inner pipe). A commercial CFD program, Ansys Fluent, was used with SST k-ω turbulence model. The effects of the geometric parameters of the fin on the inner tube were analyzed under the periodic boundary condition. The result indicated that most parameters had a tendency to increase with an increase in the height and angle of the fin. However, it was confirmed that the Nusselt number of the inner tube on the coaxial 15, 5, 0.3 was lower than that of the smooth tube. Additionally, the Nusselt number of the inner tube exhibited a tendency of decreasing with a decrease in the spacing in Coaxial 15, S{sub f}, 0.3.

  2. Enhancement of single mode operation in coaxial optical waveguide using DB boundary conditions

    Science.gov (United States)

    Lohia, Pooja; Prajapati, Y.; Saini, J. P.; Rai, B. S.

    2014-11-01

    In this study, a competent numerical strategy to compute the dispersion of optical waveguides is presented and propagation of electromagnetic waves in a coaxial optical waveguide with DB boundary conditions is instigated. For this intend, cylindrical coordinates are here being used to derive the DB boundary conditions and to obtain field components for the modes. The propagation constant for the waveguide to be studied is determined by solving the Bessel and the modified Bessel functions. The cutoff frequencies for various lower order modes have been calculated and their dispersion characteristics are plotted correspondingly. The behavior of the coaxial optical waveguide under DB boundary conditions is shown to be significantly different from that of coaxial optical waveguide and conventional optical waveguide under traditional or tangential boundary conditions. Finally, the effect of waveguide dimensions on the mode cutoff frequencies and fabrication issues are also addressed.

  3. Collapsed polymer-directed synthesis of multicomponent coaxial-like nanostructures

    KAUST Repository

    Huang, Zhiqi

    2016-07-19

    Multicomponent colloidal nanostructures (MCNs) exhibit intriguing topologically dependent chemical and physical properties. However, there remain significant challenges in the synthesis of MCNs with high-order complexity. Here we show the development of a general yet scalable approach for the rational design and synthesis of MCNs with unique coaxial-like construction. The site-preferential growth in this synthesis relies on the selective protection of seed nanoparticle surfaces with locally defined domains of collapsed polymers. By using this approach, we produce a gallery of coaxial-like MCNs comprising a shaped Au core surrounded by a tubular metal or metal oxide shell. This synthesis is robust and not prone to variations in kinetic factors of the synthetic process. The essential role of collapsed polymers in achieving anisotropic growth makes our approach fundamentally distinct from others. We further demonstrate that this coaxial-like construction can lead to excellent photocatalytic performance over conventional core–shell-type MCNs.

  4. Measurement scheme of kicker impedances via beam-induced voltages of coaxial cables

    Energy Technology Data Exchange (ETDEWEB)

    Shobuda, Yoshihiro, E-mail: yoshihiro.shobuda@j-parc.jp [J-PARC Center, JAEA and KEK, 2-4 Shirakata Shirane, Tokaimura, Nakagun, Ibaraki 319-1195 (Japan); Irie, Yoshiro [KEK, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Toyama, Takeshi; Kamiya, Junichiro [J-PARC Center, JAEA and KEK, 2-4 Shirakata Shirane, Tokaimura, Nakagun, Ibaraki 319-1195 (Japan); Watanabe, Masao [Ministry of Education, Culture, Sports, Science and Technology, 3-2-2 Kasumigaseki, Chiyoda, Tokyo 100-8959 (Japan)

    2013-06-11

    A new theory, which satisfies the causality condition, is developed to describe impedances of kicker magnets with coaxial cables. The theoretical results well describe measurement results, which are obtained by standard wire methods. On the other hand, when beams pass through the kicker, voltages are induced at the terminals of coaxial cables. In other words, by analyzing the voltages, the kicker impedance for the beams can be obtained. The observed impedances are consistent with the theoretical results. The theory describes the impedance for non-relativistic beams, as well. The theoretical, simulation and measurement results indicate that the horizontal kicker impedance is drastically reduced by the non-relativistic effect. -- Highlights: ► We develop an innovative method to measure kicker impedance including power cable. ► By analyzing voltages at the ends of coaxial cables, the impedance is derived. ► The horizontal impedance is reduced as the beam becomes non-relativistic.

  5. Split School of High Energy Physics 2015

    CERN Document Server

    2015-01-01

    Split School of High Energy Physics 2015 (SSHEP 2015) was held at the Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture (FESB), University of Split, from September 14 to September 18, 2015. SSHEP 2015 aimed at master and PhD students who were interested in topics pertaining to High Energy Physics. SSHEP 2015 is the sixth edition of the High Energy Physics School. Previous five editions were held at the Department of Physics, University of Sarajevo, Bosnia and Herzegovina.

  6. Split-plot designs for multistage experimentation

    DEFF Research Database (Denmark)

    Kulahci, Murat; Tyssedal, John

    2016-01-01

    at the same time will be more efficient. However, there have been only a few attempts in the literature to provide an adequate and easy-to-use approach for this problem. In this paper, we present a novel methodology for constructing two-level split-plot and multistage experiments. The methodology is based...... be accommodated in each stage. Furthermore, split-plot designs for multistage experiments with good projective properties are also provided....

  7. Splitting automorphisms of free Burnside groups

    International Nuclear Information System (INIS)

    Atabekyan, Varuzhan S

    2013-01-01

    It is proved that, if the order of a splitting automorphism of odd period n≥1003 of a free Burnside group B(m,n) is a prime, then the automorphism is inner. This implies, for every prime n≥1009, an affirmative answer to the question on the coincidence of the splitting automorphisms of period n of the group B(m,n) with the inner automorphisms (this question was posed in the 'Kourovka Notebook' in 1990). Bibliography: 17 titles.

  8. Are Ducted Mini-Splits Worth It?

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, Jonathan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Maguire, Jeffrey B [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Metzger, Cheryn E. [Pacific Northwest National Laboratory; Zhang, Jason [Pacific Northwest National Laboratory

    2018-02-01

    Ducted mini-split heat pumps are gaining popularity in some regions of the country due to their energy-efficient specifications and their ability to be hidden from sight. Although product and install costs are typically higher than the ductless mini-split heat pumps, this technology is well worth the premium for some homeowners who do not like to see an indoor unit in their living area. Due to the interest in this technology by local utilities and homeowners, the Bonneville Power Administration (BPA) has funded the Pacific Northwest National Laboratory (PNNL) and the National Renewable Energy Laboratory (NREL) to develop capabilities within the Building Energy Optimization (BEopt) tool to model ducted mini-split heat pumps. After the fundamental capabilities were added, energy-use results could be compared to other technologies that were already in BEopt, such as zonal electric resistance heat, central air source heat pumps, and ductless mini-split heat pumps. Each of these technologies was then compared using five prototype configurations in three different BPA heating zones to determine how the ducted mini-split technology would perform under different scenarios. The result of this project was a set of EnergyPlus models representing the various prototype configurations in each climate zone. Overall, the ducted mini-split heat pumps saved about 33-60% compared to zonal electric resistance heat (with window AC systems modeled in the summer). The results also showed that the ducted mini-split systems used about 4% more energy than the ductless mini-split systems, which saved about 37-64% compared to electric zonal heat (depending on the prototype and climate).

  9. Mort Rainey's Split Personality in Secret Window

    OpenAIRE

    Sandjaya, Cynthya; Limanta, Liem Satya

    2013-01-01

    Psychological issue is the main issue discussed in David Koepp's Secret Window through its main character, Mort Rainey. Rainey's psychological struggle will be the main theme in this research. This thesis examines Rainey's split personality. Furthermore, in this study, we want to analyze the process of how Mort Rainey's personality splits into two different personalities. To meet the answer of this study, we will use the theory of Dissociative Identity Disorder with a support from Sigmund Fre...

  10. Polarization Insensitivity in Double-Split Ring and Triple-Split Ring Terahertz Resonators

    International Nuclear Information System (INIS)

    Wu Qian-Nan; Lan Feng; Tang Xiao-Pin; Yang Zi-Qiang

    2015-01-01

    A modified double-split ring resonator and a modified triple-split ring resonator, which offer polarization-insensitive performance, are investigated, designed and fabricated. By displacing the two gaps of the conventional double-split ring resonator away from the center, the second resonant frequency for the 0° polarized wave and the resonant frequency for the 90° polarized wave become increasingly close to each other until they are finally identical. Theoretical and experimental results show that the modified double-split ring resonator and the modified triple-split ring resonator are insensitive to different polarized waves and show strong resonant frequency dips near 433 and 444 GHz, respectively. The results of this work suggest new opportunities for the investigation and design of polarization-dependent terahertz devices based on split ring resonators. (paper)

  11. CT-guided transthoracic cutting needle biopsy of intrathoracic lesions: Comparison between coaxial and single needle technique

    International Nuclear Information System (INIS)

    Wu, Reng-Hong; Tzeng, Wen-Sheng; Lee, Wei-Jing; Chang, Shih-Chin; Chen, Chia-Huei; Fung, Jui-Lung; Wang, Yen-Jen; Mak, Chee-Wai

    2012-01-01

    Purpose: To evaluate the complication rates and diagnostic accuracy of two different CT-guided transthoracic cutting needle biopsy techniques: coaxial method and single needle method. Methods: This study involved 198 consecutive subjects with 198 intrathoracic lesions. The first 98 consecutive subjects received a single needle cutting technique and the next 100 consecutive subjects received a coaxial technique. Both groups were compared in relation the diagnostic accuracy and complication rates. Results: No significant difference was found between the two groups concerning patient characteristics, lesions and procedure variables. There was a borderline statistical difference in the incidence of pneumothorax at within 24-h post biopsy between patients in the single needle group (5%) and the coaxial group (13%) (P = 0.053). Little difference was found in the pneumothorax rate at immediately post biopsy between the two groups, which was 28% in the single needle group and 31% in the coaxial group. There was no significant difference in the hemoptysis rate between the two groups, which was 9.2% in the single needle group and 11% in the coaxial group. Both techniques yielded an overall diagnostic accuracy of 98% for malignant lesions with similar sensitivity (single needle: 96.9% vs. coaxial: 96.4%) and specificity (single needle: 100% vs. coaxial: 100%). Conclusion: There is little difference in the pneumothorax rates and bleeding complications between patients who either received a single needle or a coaxial transthoracic cutting biopsy. Both techniques produce an overall diagnostic accuracy of 98% for malignant lesions.

  12. Numerical investigation on liquid sheets interaction characteristics of liquid-liquid coaxial swirling jets in bipropellant thruster

    International Nuclear Information System (INIS)

    Ding, Jia-Wei; Li, Guo-Xiu; Yu, Yu-Song

    2016-01-01

    Highlights: • A LES-VOF model is conducted to simulate atomization of coaxial swirling jets. • Structure and flow field of coaxial swirling jets are investigated. • Merging process occurs at the nozzle exit and generates additional perturbation. • The Rayleigh mode instability dominates the breakup of ligaments. - Abstract: Spray atomization process of a liquid-liquid coaxial swirl injector in bipropellant thruster has been investigated using volume of fluid (VOF) method coupled with large eddy simulation methodology. With fine grid resolution, detailed flow field of interacted liquid sheet has been captured and analyzed. For coaxial swirling jet, static pressure drop in the region between the liquid sheets makes two liquid sheets to approach each other and merge. A strong pressure, velocity and turbulent fluctuations are calculated near the contact position of two coaxial jets. Simulation results indicate that additional perturbations are generated due to strong radial and axial shear effects between coaxial jets. Observation of droplet formation process reveals that the Rayleigh mode instability dominates the breakup of the ligament. Droplet diameter and distribution have been investigated quantitatively. The mean diameter of the coaxial jets is between that of the inner and the outer jets. Compared with the individual swirling jets, wider size distributions of droplets are produced in the coaxial jets.

  13. Vegetation dielectric characterization using an open-ended coaxial probe

    Science.gov (United States)

    Mavrovic, A.; Roy, A.; Royer, A.; Boone, F.; Pappas, C.; Filali, B.

    2017-12-01

    The detection of freeze/thaw (F/T) physical state of soil is one of the main objectives of the SMAP mission as well as one of the secondary objectives of the SMOS mission. Annual F/T cycles have substantial impacts on surface energy budgets, permafrost conditions, as well as forest water and carbon dynamics. It has been shown that spaceborne L-band passive radiometry is a promising tool to monitor F/T due to the substantial differences between the permittivity of water and ice at these frequencies. However, the decoupling of the signal between soil and vegetation components remains challenging for all microwave remote sensing applications at various spatial scales. Radiative transfer models in the microwave domain are generally poorly parameterized to consider the non-negligible contribution of vegetation. The main objective of this research is to assess the skill of a recently developed Open-Ended Coaxial Probe (OECP) to measure the complex microwave permittivity of vegetation and soils and to derive a relation between the impact of vegetation on the microwave signal and the vegetation permittivity that could serve as a validation tool for soil models especially in frozen state. Results show that the OECP is a suitable tool to infer the radial profile of the complex permittivity in L-band of trees. A clear distinction can be made between the dielectric characterization of the sapwood where the permittivity is high because of the high permittivity of water but decrease with depth, and the heartwood where the permittivity is low and relatively constant. The seasonal cycle of the F/T state of the vegetation can also be observed since it is strongly correlated with the permittivity of the wood. The permittivity of a tree over the winter season is very low and homogenous since the permittivity of ice is significantly lower than water and the sap flow is negligible. The fluctuation of the frozen and thawed permittivity for different tree species was evaluated, focusing

  14. A novel technique for tuning of co-axial cavity of multi-beam klystron

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Sukalyan, E-mail: sstechno18@gmail.com; Bandyopadhyay, Ayan Kumar; Pal, Debashis; Kant, Deepender; Joshi, Lalit Mohan; Kumar, Bijendra; Meena, Rakesh; Rawat, Vikram [Microwave Tubes Division, CSIR-CEERI, Pilani, Rajasthan-333031 (India)

    2016-03-09

    Multi-beam Klystrons (MBKs) have gained wide acceptances in the research sector for its inherent advantages. But developing a robust tuning technique for an MBK cavity of coaxial type has still remained a challenge as these designs are very prone to suffer from asymmetric field distribution with inductive tuning of the cavity. Such asymmetry leads to inhomogeneous beam-wave interaction, an undesirable phenomenon. Described herein is a new type of coaxial cavity that has the ability to suppress the asymmetry, thereby allowing tuning of the cavity with a single tuning post.

  15. A 2 MW, 170 GHz coaxial cavity gyrotron - experimental verification of the design of main components

    Energy Technology Data Exchange (ETDEWEB)

    Piosczyk, B [Forschungszentrum Karlsruhe, Association EURATOM-FZK, Institut fuer Hochleistungsimpuls- und Mikrowellentechnik (IHM), Postfach 3640, D-76021 Karlsruhe (Germany); Dammertz, G [Forschungszentrum Karlsruhe, Association EURATOM-FZK, Institut fuer Hochleistungsimpuls- und Mikrowellentechnik (IHM), Postfach 3640, D-76021 Karlsruhe (Germany); Dumbrajs, O [Department of Engineering Physics and Mathematics, Helsinki University of Technology, Association EURATOM-TEKES, FIN-02150 Espoo (Finland)] (and others)

    2005-01-01

    A 2 MW, CW, 170 GHz coaxial cavity gyrotron is under development in cooperation between European Research Institutions (FZK Karlsruhe, CRPP Lausanne, HUT Helsinki) and the European tube industry (TED, Velizy, France). The design of critical components has recently been examined experimentally at FZK Karlsruhe with a short pulse ({approx} few ms) coaxial cavity gyrotron. This gyrotron uses the same cavity and the same quasioptical (q.o.) RF-output system as designed for the industrial prototype and a very similar electron gun.

  16. Design, fabrication and comparison of two power combiners: cylindrical and coaxial cavities

    Directory of Open Access Journals (Sweden)

    A M Poursaleh

    2017-08-01

    Full Text Available Resonant structure is one of the proposed methods in combining power in RF systems of  RF accelerators. In this structure, fabrication of RF power divider or combiner using coaxial and cylindrical cavity is important. In this study, two combiners, in the same frequency band, are designed and fabricated; and their results are compared. The experimental results confirmed the simulation results and showed that compared with cyclical cavity, the power combiner with coaxial cavity is smaller, more easily adjustable, and is more suitable for use in RF systems of RF accelerators

  17. Development of coaxial ultrasonic probe for fatty liver diagnostic system using ultrasonic velocity change

    Science.gov (United States)

    Hori, Makoto; Yokota, Daiki; Aotani, Yuhei; Kumagai, Yuta; Wada, Kenji; Matsunaka, Toshiyuki; Morikawa, Hiroyasu; Horinaka, Hiromichi

    2017-07-01

    A diagnostic system for fatty liver at an early stage is needed because fatty liver is linked to metabolic syndrome. We have already proposed a fatty liver diagnosis method based on the temperature coefficient of ultrasonic velocity. In this study, we fabricated a coaxial ultrasonic probe by integrating two kinds of transducers for warming and signal detection. The diagnosis system equipped with the coaxial probe was applied to tissue-mimicking phantoms including the fat area. The fat content rates corresponding to the set rates of the phantoms were estimated by the ultrasonic velocity-change method.

  18. A comparison of the screening performance of braided coaxial and triaxial cables

    International Nuclear Information System (INIS)

    Fowler, E.P.

    1975-03-01

    The screening performance of a coaxial screened circuit is derived from measurements of the surface transfer impedance, capacitive coupling and conductor eccentricity on short lengths of cable. This is then extended to a triaxial screen considering all the ways the two screens can be connected. Comparison of calculated performance and measured results on a 10m length show that the mechanisms of coupling interact to make triaxial cable screening worse than expected and, in fact, frequently no better than a coaxial cable. The use of superscreened cables is found to overcome all the problems known in triaxial cables. (author)

  19. Modeling of Coaxial Slot Waveguides Using Analytical and Numerical Approaches: Revisited

    Directory of Open Access Journals (Sweden)

    Kok Yeow You

    2012-01-01

    Full Text Available Our reviews of analytical methods and numerical methods for coaxial slot waveguides are presented. The theories, background, and physical principles related to frequency-domain electromagnetic equations for coaxial waveguides are reassessed. Comparisons of the accuracies of various types of admittance and impedance equations and numerical simulations are made, and the fringing field at the aperture sensor, which is represented by the lumped capacitance circuit, is evaluated. The accuracy and limitations of the analytical equations are explained in detail. The reasons for the replacement of analytical methods by numerical methods are outlined.

  20. Coaxial Thermoplastic Elastomer-Wrapped Carbon Nanotube Fibers for Deformable and Wearable Strain Sensors

    KAUST Repository

    Zhou, Jian

    2018-01-22

    Highly conductive and stretchable fibers are crucial components of wearable electronics systems. Excellent electrical conductivity, stretchability, and wearability are required from such fibers. Existing technologies still display limited performances in these design requirements. Here, achieving highly stretchable and sensitive strain sensors by using a coaxial structure, prepared via coaxial wet spinning of thermoplastic elastomer-wrapped carbon nanotube fibers, is proposed. The sensors attain high sensitivity (with a gauge factor of 425 at 100% strain), high stretchability, and high linearity. They are also reproducible and durable. Their use as safe sensing components on deformable cable, expandable surfaces, and wearable textiles is demonstrated.

  1. All carbon coaxial supercapacitors based on hollow carbon nanotube sleeve structure

    International Nuclear Information System (INIS)

    Zang, Xiaobei; Xu, Ruiqiao; Zhang, Yangyang; Zhang, Li; Wei, Jinquan; Wang, Kunlin; Zhu, Hongwei; Li, Xinming

    2015-01-01

    All carbon coaxial supercapacitors based on hollow carbon nanotube (CNT) sleeve structure are assembled and tested. The key advantage of the structure is that the inner core electrode is variable from CNT sleeve sponges, to CNT fibers, reduced graphene oxide fibers, and graphene woven fabrics. By changing core electrodes from sleeve sponges to CNT fibers, the electrochemical performance has been significantly enhanced. The capacitance based on sleeve sponge + CNT fiber double the capacitances of double-sleeve sponge supercapacitors thanks to reduction of the series and internal resistances. Besides, the coaxial sleeve structure possesses many other features, including high rate capacitance, long cycle life, and good flexibility. (paper)

  2. Reversal of Flux Closure States in Cobalt Nanoparticle Rings With Coaxial Magnetic Pulses

    DEFF Research Database (Denmark)

    Kasama, T; Dunin-Borkowski, Rafal E.; Scheinfein, MR

    2008-01-01

    Bistable flux closure (FC) states in Co nanoparticle rings can be switched reversibly by applying a coaxial magnetic field (H-z). The FC switching phenomena can be reproduced by micromagnetics simulations, which also reveal novel magnetic states at intermediate applied field strengths.......Bistable flux closure (FC) states in Co nanoparticle rings can be switched reversibly by applying a coaxial magnetic field (H-z). The FC switching phenomena can be reproduced by micromagnetics simulations, which also reveal novel magnetic states at intermediate applied field strengths....

  3. Multipactor in a Coaxial Line Under the Presence of an Axial DC Magnetic Field

    CERN Document Server

    González-Iglesias, D; Anza, S; Vague, J; Gimeno, B; Boria, V E; Raboso, D; Vicente, C; Gil, J; Caspers, F; Conde, L

    2012-01-01

    The main goal of this letter is the analysis of the multipactor effect within a coaxial waveguide structure when an external axial dc magnetic field is applied. We have designed and manufactured a coaxial waveguide sample that has been immersed within a long solenoid. Numerical and experimental results confirm a significant change in the RF breakdown behavior with regard to the case without the axial dc magnetic field, as well as the existence of single- and double-surface multipactor regimes. Good agreement between theory and experimental data has been found.

  4. Evaluation of Mandibular Anatomy Associated With Bad Splits in Sagittal Split Ramus Osteotomy of Mandible.

    Science.gov (United States)

    Wang, Tongyue; Han, Jeong Joon; Oh, Hee-Kyun; Park, Hong-Ju; Jung, Seunggon; Park, Yeong-Joon; Kook, Min-Suk

    2016-07-01

    This study aimed to identify risk factors associated with bad splits during sagittal split ramus osteotomy by using three-dimensional computed tomography. This study included 8 bad splits and 47 normal patients without bad splits. Mandibular anatomic parameters related to osteotomy line were measured. These included anteroposterior width of the ramus at level of lingula, distance between external oblique ridge and lingula, distance between sigmoid notch and inferior border of mandible, mandibular angle, distance between inferior outer surface of mandibular canal and inferior border of mandible under distal root of second molar (MCEM), buccolingual thickness of the ramus at level of lingula, and buccolingual thickness of the area just distal to first molar (BTM1) and second molar (BTM2). The incidence of bad splits in 625 sagittal split osteotomies was 1.28%. Compared with normal group, bad split group exhibited significantly thinner BTM2 and shorter sigmoid notch and inferior border of mandible (P bad splits. These anatomic data may help surgeons to choose the safest surgical techniques and best osteotomy sites.

  5. An algorithm for the split-feasibility problems with application to the split-equality problem.

    Science.gov (United States)

    Chuang, Chih-Sheng; Chen, Chi-Ming

    2017-01-01

    In this paper, we study the split-feasibility problem in Hilbert spaces by using the projected reflected gradient algorithm. As applications, we study the convex linear inverse problem and the split-equality problem in Hilbert spaces, and we give new algorithms for these problems. Finally, numerical results are given for our main results.

  6. Pneumothorax Complicating Coaxial and Non-coaxial CT-Guided Lung Biopsy: Comparative Analysis of Determining Risk Factors and Management of Pneumothorax in a Retrospective Review of 650 Patients

    Energy Technology Data Exchange (ETDEWEB)

    Nour-Eldin, Nour-Eldin A., E-mail: nour410@hotmail.com; Alsubhi, Mohammed, E-mail: mohammedal-subhi@yahoo.com; Emam, Ahmed, E-mail: morgan101002@hotmail.com; Lehnert, Thomas, E-mail: thomas.lehnert@kgu.de; Beeres, Martin, E-mail: beeres@gmx.net; Jacobi, Volkmar, E-mail: volkmar.jacobi@kgu.de; Gruber-Rouh, Tatjana, E-mail: tatjanagruber2004@yahoo.com; Scholtz, Jan-Erik, E-mail: janerikscholtz@gmail.com; Vogl, Thomas J., E-mail: t.vogl@em.uni-frankfurt.de; Naguib, Nagy N., E-mail: nagynnn@yahoo.com [Johan Wolfgang Goethe – University Hospital, Institute for Diagnostic and Interventional Radiology (Germany)

    2016-02-15

    PurposeTo assess the scope and determining risk factors related to the development of pneumothorax throughout CT-guided biopsy of pulmonary lesions in coaxial and non-coaxial techniques and the outcome of its management.Materials and MethodsThe study included CT-guided percutaneous lung biopsies in 650 consecutive patients (407 males, 243 females; mean age 54.6 years, SD 5.2) from November 2008 to June 2013 in a retrospective design. Patients were classified according to lung biopsy technique into coaxial group (318 lesions) and non-coaxial group (332 lesions). Exclusion criteria for biopsy were lesions <5 mm in diameter, uncorrectable coagulopathy, positive-pressure ventilation, severe respiratory compromise, pulmonary arterial hypertension, or refusal of the procedure. Risk factors related to the occurrence of pneumothorax were classified into: (a) Technical risk factors, (b) patient-related risk factors, and (c) lesion-associated risk factors. Radiological assessments were performed by two radiologists in consensus. Mann–Whitney U test and Fisher’s exact tests were used for statistical analysis. p values <0.05 were considered statistically significant.ResultsThe incidence of pneumothorax complicating CT-guided lung biopsy was less in the non-coaxial group (23.2 %, 77 out of 332) than the coaxial group (27 %, 86 out of 318). However, the difference in incidence between both groups was statistically insignificant (p = 0.14). Significant risk factors for the development of pneumothorax in both groups were emphysema (p < 0.001 in both groups), traversing a fissure with the biopsy needle (p value 0.005 in non-coaxial group and 0.001 in coaxial group), small lesion, less than 2 cm in diameter (p value of 0.02 in both groups), location of the lesion in the basal or mid sections of the lung (p = 0.003 and <0.001 in non-coaxial and coaxial groups, respectively), and increased needle track path within the lung tissue of more than 2.5 cm (p = 0.01 in both

  7. Pneumothorax Complicating Coaxial and Non-coaxial CT-Guided Lung Biopsy: Comparative Analysis of Determining Risk Factors and Management of Pneumothorax in a Retrospective Review of 650 Patients

    International Nuclear Information System (INIS)

    Nour-Eldin, Nour-Eldin A.; Alsubhi, Mohammed; Emam, Ahmed; Lehnert, Thomas; Beeres, Martin; Jacobi, Volkmar; Gruber-Rouh, Tatjana; Scholtz, Jan-Erik; Vogl, Thomas J.; Naguib, Nagy N.

    2016-01-01

    PurposeTo assess the scope and determining risk factors related to the development of pneumothorax throughout CT-guided biopsy of pulmonary lesions in coaxial and non-coaxial techniques and the outcome of its management.Materials and MethodsThe study included CT-guided percutaneous lung biopsies in 650 consecutive patients (407 males, 243 females; mean age 54.6 years, SD 5.2) from November 2008 to June 2013 in a retrospective design. Patients were classified according to lung biopsy technique into coaxial group (318 lesions) and non-coaxial group (332 lesions). Exclusion criteria for biopsy were lesions <5 mm in diameter, uncorrectable coagulopathy, positive-pressure ventilation, severe respiratory compromise, pulmonary arterial hypertension, or refusal of the procedure. Risk factors related to the occurrence of pneumothorax were classified into: (a) Technical risk factors, (b) patient-related risk factors, and (c) lesion-associated risk factors. Radiological assessments were performed by two radiologists in consensus. Mann–Whitney U test and Fisher’s exact tests were used for statistical analysis. p values <0.05 were considered statistically significant.ResultsThe incidence of pneumothorax complicating CT-guided lung biopsy was less in the non-coaxial group (23.2 %, 77 out of 332) than the coaxial group (27 %, 86 out of 318). However, the difference in incidence between both groups was statistically insignificant (p = 0.14). Significant risk factors for the development of pneumothorax in both groups were emphysema (p < 0.001 in both groups), traversing a fissure with the biopsy needle (p value 0.005 in non-coaxial group and 0.001 in coaxial group), small lesion, less than 2 cm in diameter (p value of 0.02 in both groups), location of the lesion in the basal or mid sections of the lung (p = 0.003 and <0.001 in non-coaxial and coaxial groups, respectively), and increased needle track path within the lung tissue of more than 2.5 cm (p = 0.01 in both

  8. Urban pattern: Layout design by hierarchical domain splitting

    KAUST Repository

    Yang, Yongliang; Wang, Jun; Vouga, Etienne; Wonka, Peter

    2013-01-01

    We present a framework for generating street networks and parcel layouts. Our goal is the generation of high-quality layouts that can be used for urban planning and virtual environments. We propose a solution based on hierarchical domain splitting using two splitting types: streamline-based splitting, which splits a region along one or multiple streamlines of a cross field, and template-based splitting, which warps pre-designed templates to a region and uses the interior geometry of the template as the splitting lines. We combine these two splitting approaches into a hierarchical framework, providing automatic and interactive tools to explore the design space.

  9. Urban pattern: Layout design by hierarchical domain splitting

    KAUST Repository

    Yang, Yongliang

    2013-11-06

    We present a framework for generating street networks and parcel layouts. Our goal is the generation of high-quality layouts that can be used for urban planning and virtual environments. We propose a solution based on hierarchical domain splitting using two splitting types: streamline-based splitting, which splits a region along one or multiple streamlines of a cross field, and template-based splitting, which warps pre-designed templates to a region and uses the interior geometry of the template as the splitting lines. We combine these two splitting approaches into a hierarchical framework, providing automatic and interactive tools to explore the design space.

  10. Superradiant laser emission from rhodamine 6G and rhodamine B using a coaxial flashpump.

    Science.gov (United States)

    Mumola, P. B.

    1972-01-01

    Superradiant laser emission has been observed from ethanol solutions of rhodamine 6G and rhodamine B using a coaxial flashlamp pump. The dependence of input threshold energy on dye concentration is examined. The possibility of exciting other dyes to superradiance is discussed.

  11. Study of the electrical signals observed during the initial stage in a coaxial gun

    International Nuclear Information System (INIS)

    Moreno, C.; Vieytes, R.

    1995-01-01

    In this work high frequency oscillations further experimental data, along with its theoretical modeling will be given for initial phase in a coaxial gun constructed to be used in technological applications of plasma. Particular attention was devoted to find any dependence between the measured frequencies and the operating pressure and voltage. 1 ref., 1 fig., 1 tab

  12. Axial magnetic field restriction of plasma sheath in a coaxial discharge

    International Nuclear Information System (INIS)

    Masoud, M. M.; Soliman, H. M.; Ibrahim, F. A.

    1999-01-01

    The study deals with the effect of an applied axial magnetic field on the dynamics and parameters of the plasma sheath and the expanded plasma in a coaxial discharge. Experimental investigations were carried out with a 3 kJ coaxial discharge device of a Mather geometry. The discharge takes place in Hydrogen gas with base pressure of 1 torr. The experiments were conducted with a 10 kV bank voltage, which corresponds to 100 kA discharge currents. The investigations have shown that the maximum axial plasma sheath velocity is decreased by 20% when applying the external axial magnetic field along the coaxial electrodes of intensity 2.6 kG. The experimental results of axial magnetic field intensity B z along the coaxial electrodes indicated that the application of external axial magnetic field causes an increases of B z ∼ 40% at a mid-distance between the breech and the muzzle and a decrease by 75% at the muzzle. The experimental results of expanded plasma electron temperature T e and density n e cleared that when the axial magnetic field is applied the maximum T e is decreased by 2.6 and 3 times, while the maximum n e is increased by 2.8 and 2 times for the first and second half cycles respectively. (author)

  13. Use of coaxial plasma guns to start up field-reversed-mirror reactors

    International Nuclear Information System (INIS)

    Smith, A.C. Jr.; Carlson, G.A.; Eddleman, J.L.; Hartman, C.W.; Neef, W.S. Jr.

    1980-01-01

    Application of a magnetized coaxial plasma gun for start-up of a field-reversed-mirror reactor is considered. The design is based on preliminary scaling laws and is compared to the design of the start-up gun used in the Beta II experiment

  14. The geomagnetic field - An explanation for the microturbulence in coaxial gun plasmas

    International Nuclear Information System (INIS)

    Mather, J.W.; Ahluwalia, H.S.

    1988-01-01

    The authors describe the complexity introduced by the geomagnetic field in several regions of a coaxial gun plasma device. It is shown that the annihilation of the swept-up geomagnetic flux, trapped within the highly compressed turbulent plasma, provides an explanation for varied performance and experimental results

  15. Improved theory of time domain reflectometry with variable coaxial cable length for electrical conductivity measurements

    Science.gov (United States)

    Although empirical models have been developed previously, a mechanistic model is needed for estimating electrical conductivity (EC) using time domain reflectometry (TDR) with variable lengths of coaxial cable. The goals of this study are to: (1) derive a mechanistic model based on multisection tra...

  16. Coaxiality of stress and strain in anisotropic no-tension materials

    Czech Academy of Sciences Publication Activity Database

    Padovani, C.; Šilhavý, Miroslav

    2013-01-01

    Roč. 48, č. 2 (2013), s. 487-489 ISSN 0025-6455 Institutional support: RVO:67985840 Keywords : anisotropy * coaxiality * no-tension materials Subject RIV: BA - General Mathematics Impact factor: 1.815, year: 2013 http://link.springer.com/article/10.1007%2Fs11012-012-9690-7

  17. Nonlinear theory of a cyclotron autoresonance maser (CARM) amplifier with outer-slotted-coaxial waveguide

    International Nuclear Information System (INIS)

    Qiu Chunrong; Ouyang Zhengbiao; Zhang Shichang; Zhang Huibo; Jin Jianbo; Lai Yingxin

    2005-01-01

    A self-consistent nonlinear theory for the outer-slotted-coaxial-waveguide cyclotron autoresonance maser (CARM) amplifier is presented, which includes the characteristic equation of the wave, coupling equation of the wave with the relativistic electron beam and the simulation model. The influences of the magnetic field, the slot depth and width are investigated. The interesting characteristic of the device is that the mode competition can be efficiently suppressed by slotting the outer wall of the coaxial waveguide. A typical example is given by the theoretical design of a 137 GHz outer-slotted-coaxial-waveguide CARM amplifier by utilizing an electron beam with a voltage of 90 kV, current of 50 A, velocity pitch angle of 0.85 and a magnetic field of 43.0 kG. The nonlinear simulation predicts a power of 467.9 kW, an electronic efficiency of 10.4% and a saturated gain of 46.7 dB, if the electron beam has no velocity spread. However, the axial velocity spread deteriorates the device; for example, if the axial velocity spread is 2%, the peak power decreases to 332.4 kW with an efficiency of 7.4% and a saturated gain of 45.22 dB. Simulation shows that the efficiency of the outer-slotted-coaxial-waveguide CARM amplifier may be increased from 10.4% to 29.6% by tapering the magnetic field

  18. Symmetric splitting of very light systems

    International Nuclear Information System (INIS)

    Grotowski, K.; Majka, Z.; Planeta, R.

    1985-01-01

    Fission reactions that produce fragments close to one half the mass of the composite system are traditionally observed in heavy nuclei. In light systems, symmetric splitting is rarely observed and poorly understood. It would be interesting to verify the existence of the symmetric splitting of compound nuclei with A 12 C + 40 Ca, 141 MeV 9 Be + 40 Ca and 153 MeV 6 Li + 40 Ca. The out-of-plane correlation of symmetric products was also measured for the reaction 186 MeV 12 C + 40 Ca. The coincidence measurements of the 12 C + 40 Ca system demonstrated that essentially all of the inclusive yield of symmetric products around 40 0 results from a binary decay. To characterize the dependence of the symmetric splitting process on the excitation energy of the 12 C + 40 C system, inclusive measurements were made at bombarding energies of 74, 132, 162, and 185 MeV

  19. High efficiency beam splitting for H- accelerators

    International Nuclear Information System (INIS)

    Kramer, S.L.; Stipp, V.; Krieger, C.; Madsen, J.

    1985-01-01

    Beam splitting for high energy accelerators has typically involved a significant loss of beam and radiation. This paper reports on a new method of splitting beams for H - accelerators. This technique uses a high intensity flash of light to strip a fraction of the H - beam to H 0 which are then easily separated by a small bending magnet. A system using a 900-watt (average electrical power) flashlamp and a highly efficient collector will provide 10 -3 to 10 -2 splitting of a 50 MeV H - beam. Results on the operation and comparisons with stripping cross sections are presented. Also discussed is the possibility for developing this system to yield a higher stripping fraction

  20. Optimal Aerodynamic Design of Conventional and Coaxial Helicopter Rotors in Hover and Forward Flight

    Science.gov (United States)

    Giovanetti, Eli B.

    This dissertation investigates the optimal aerodynamic performance and design of conventional and coaxial helicopters in hover and forward flight using conventional and higher harmonic blade pitch control. First, we describe a method for determining the blade geometry, azimuthal blade pitch inputs, optimal shaft angle (rotor angle of attack), and division of propulsive and lifting forces among the components that minimize the total power for a given forward flight condition. The optimal design problem is cast as a variational statement that is discretized using a vortex lattice wake to model inviscid forces, combined with two-dimensional drag polars to model profile losses. The resulting nonlinear constrained optimization problem is solved via Newton iteration. We investigate the optimal design of a compound vehicle in forward flight comprised of a coaxial rotor system, a propeller, and optionally, a fixed wing. We show that higher harmonic control substantially reduces required power, and that both rotor and propeller efficiencies play an important role in determining the optimal shaft angle, which in turn affects the optimal design of each component. Second, we present a variational approach for determining the optimal (minimum power) torque-balanced coaxial hovering rotor using Blade Element Momentum Theory including swirl. We show that the optimal hovering coaxial rotor generates only a small percentage of its total thrust on the portion of the lower rotor operating in the upper rotor's contracted wake, resulting in an optimal design with very different upper and lower rotor twist and chord distributions. We also show that the swirl component of induced velocity has a relatively small effect on rotor performance at the disk loadings typical of helicopter rotors. Third, we describe a more refined model of the wake of a hovering conventional or coaxial rotor. We approximate the rotor or coaxial rotors as actuator disks (though not necessarily uniformly loaded

  1. Electroweak splitting functions and high energy showering

    Science.gov (United States)

    Chen, Junmou; Han, Tao; Tweedie, Brock

    2017-11-01

    We derive the electroweak (EW) collinear splitting functions for the Standard Model, including the massive fermions, gauge bosons and the Higgs boson. We first present the splitting functions in the limit of unbroken SU(2) L × U(1) Y and discuss their general features in the collinear and soft-collinear regimes. These are the leading contributions at a splitting scale ( k T ) far above the EW scale ( v). We then systematically incorporate EW symmetry breaking (EWSB), which leads to the emergence of additional "ultra-collinear" splitting phenomena and naive violations of the Goldstone-boson Equivalence Theorem. We suggest a particularly convenient choice of non-covariant gauge (dubbed "Goldstone Equivalence Gauge") that disentangles the effects of Goldstone bosons and gauge fields in the presence of EWSB, and allows trivial book-keeping of leading power corrections in v/ k T . We implement a comprehensive, practical EW showering scheme based on these splitting functions using a Sudakov evolution formalism. Novel features in the implementation include a complete accounting of ultra-collinear effects, matching between shower and decay, kinematic back-reaction corrections in multi-stage showers, and mixed-state evolution of neutral bosons ( γ/ Z/ h) using density-matrices. We employ the EW showering formalism to study a number of important physical processes at O (1-10 TeV) energies. They include (a) electroweak partons in the initial state as the basis for vector-boson-fusion; (b) the emergence of "weak jets" such as those initiated by transverse gauge bosons, with individual splitting probabilities as large as O (35%); (c) EW showers initiated by top quarks, including Higgs bosons in the final state; (d) the occurrence of O (1) interference effects within EW showers involving the neutral bosons; and (e) EW corrections to new physics processes, as illustrated by production of a heavy vector boson ( W ') and the subsequent showering of its decay products.

  2. Double Coaxial Microcatheter Technique for Glue Embolization of Renal Arteriovenous Malformations

    International Nuclear Information System (INIS)

    Uchikawa, Yoko; Mori, Kensaku; Shiigai, Masanari; Konishi, Takahiro; Hoshiai, Sodai; Ishigro, Toshitaka; Hiyama, Takashi; Nakai, Yasunobu; Minami, Manabu

    2015-01-01

    PurposeTo demonstrate the technical benefit of the double coaxial microcatheter technique for embolization of renal arteriovenous malformations (AVMs) with n-butyl cyanoacrylate and iodized oil (glue).Materials and MethodsSix consecutive patients (1 man and 5 women; mean age 61 years; range 44–77 years) with renal AVMs were included. Five patients had hematuria, and one had a risk of heart failure due to a large intrarenal arteriovenous shunt. All patients underwent transarterial embolization using glue and the double coaxial microcatheter technique with outer 2.6F and inner 1.9F microcatheters. After glue injection, the inner microcatheter was retracted, while the outer microcatheter was retained. We assessed the complications and clinical outcomes of this technique.ResultsTechnical success was achieved in all patients. In 9 sessions, 34 feeding arteries were embolized with glue using the double coaxial microcatheter technique, 1 was embolized with glue using a single microcatheter, and 2 were embolized with coils. The double coaxial microcatheter technique was useful for selecting small tortuous feeding arteries, preventing glue reflux to the proximal arteries, and approaching multiple feeding arteries without complete retraction of the microcatheters. As a minor complication, glue migrated into the venous system in four patients without any sequelae. In all patients, favorable clinical outcomes, including hematuria cessation in five patients and improvement of the large intrarenal arteriovenous shunt in one patient, were obtained without deterioration of renal function.ConclusionGlue embolization with the double coaxial microcatheter technique was useful for treating renal AVMs with multiple tortuous feeding arteries

  3. Double Coaxial Microcatheter Technique for Glue Embolization of Renal Arteriovenous Malformations

    Energy Technology Data Exchange (ETDEWEB)

    Uchikawa, Yoko, E-mail: jauchikawa@gmail.com [University of Tsukuba Hospital, Department of Radiology (Japan); Mori, Kensaku, E-mail: moriken@md.tsukuba.ac.jp [University of Tsukuba, Department of Radiology, Faculty of Medicine (Japan); Shiigai, Masanari, E-mail: m-41gai@yahoo.co.jp [Tsukuba Medical Center Hospital, Department of Radiology (Japan); Konishi, Takahiro, E-mail: soratobukangaruu@gmail.com [University of Tsukuba Hospital, Department of Radiology (Japan); Hoshiai, Sodai, E-mail: hoshiai@sb4.so-net.ne.jp [Ibaraki Prefectural Central Hospital, Department of Radiology (Japan); Ishigro, Toshitaka, E-mail: suzutokei@gmail.com; Hiyama, Takashi, E-mail: med-tak@hotmail.com [University of Tsukuba Hospital, Department of Radiology (Japan); Nakai, Yasunobu, E-mail: nakaiya@tmch.or.jp [Tsukuba Medical Center Hospital, Department of Neurosurgery (Japan); Minami, Manabu, E-mail: mminami@md.tsukuba.ac.jp [University of Tsukuba, Department of Radiology, Faculty of Medicine (Japan)

    2015-10-15

    PurposeTo demonstrate the technical benefit of the double coaxial microcatheter technique for embolization of renal arteriovenous malformations (AVMs) with n-butyl cyanoacrylate and iodized oil (glue).Materials and MethodsSix consecutive patients (1 man and 5 women; mean age 61 years; range 44–77 years) with renal AVMs were included. Five patients had hematuria, and one had a risk of heart failure due to a large intrarenal arteriovenous shunt. All patients underwent transarterial embolization using glue and the double coaxial microcatheter technique with outer 2.6F and inner 1.9F microcatheters. After glue injection, the inner microcatheter was retracted, while the outer microcatheter was retained. We assessed the complications and clinical outcomes of this technique.ResultsTechnical success was achieved in all patients. In 9 sessions, 34 feeding arteries were embolized with glue using the double coaxial microcatheter technique, 1 was embolized with glue using a single microcatheter, and 2 were embolized with coils. The double coaxial microcatheter technique was useful for selecting small tortuous feeding arteries, preventing glue reflux to the proximal arteries, and approaching multiple feeding arteries without complete retraction of the microcatheters. As a minor complication, glue migrated into the venous system in four patients without any sequelae. In all patients, favorable clinical outcomes, including hematuria cessation in five patients and improvement of the large intrarenal arteriovenous shunt in one patient, were obtained without deterioration of renal function.ConclusionGlue embolization with the double coaxial microcatheter technique was useful for treating renal AVMs with multiple tortuous feeding arteries.

  4. Splitting Strategy for Simulating Genetic Regulatory Networks

    Directory of Open Access Journals (Sweden)

    Xiong You

    2014-01-01

    Full Text Available The splitting approach is developed for the numerical simulation of genetic regulatory networks with a stable steady-state structure. The numerical results of the simulation of a one-gene network, a two-gene network, and a p53-mdm2 network show that the new splitting methods constructed in this paper are remarkably more effective and more suitable for long-term computation with large steps than the traditional general-purpose Runge-Kutta methods. The new methods have no restriction on the choice of stepsize due to their infinitely large stability regions.

  5. On geometrical splitting in nonanalog Monte Carlo

    International Nuclear Information System (INIS)

    Lux, I.

    1985-01-01

    A very general geometrical procedure is considered, and it is shown how the free flights, the statistical weights and the contribution of particles participating in splitting are to be chosen in order to reach unbiased estimates in games where the transition kernels are nonanalog. Equations governing the second moment of the score and the number of flights to be stimulated are derived. It is shown that the post-splitting weights of the fragments are to be chosen equal to reach maximum gain in variance. Conditions are derived under which the expected number of flights remains finite. Simplified example illustrate the optimization of the procedure (author)

  6. Reversible perspective and splitting in time.

    Science.gov (United States)

    Hart, Helen Schoenhals

    2012-01-01

    The element of time--the experience of it and the defensive use of it--is explored in conjunction with the use of reversible perspective as a psychotic defense. Clinical material from a long analysis illustrates how a psychotic patient used the reversible perspective, with its static splitting, to abolish the experience of time. When he improved and the reversible perspective became less effective for him, he replaced it with a more dynamic splitting mechanism using time gaps. With further improvement, the patient began to experience the passage of time, and along with it the excruciating pain of separation, envy, and loss.

  7. Investigation on discharge characteristics of a coaxial dielectric barrier discharge reactor driven by AC and ns power sources

    Science.gov (United States)

    Qian, WANG; Feng, LIU; Chuanrun, MIAO; Bing, YAN; Zhi, FANG

    2018-03-01

    A coaxial dielectric barrier discharge (DBD) reactor with double layer dielectric barriers has been developed for exhaust gas treatment and excited either by AC power or nanosecond (ns) pulse to generate atmospheric pressure plasma. The comparative study on the discharge characteristics of the discharge uniformity, power deposition, energy efficiency, and operation temperature between AC and ns pulsed coaxial DBD is carried out in terms of optical and electrical characteristics and operation temperature for optimizing the coaxial DBD reactor performance. The voltages across the air gap and dielectric layer and the conduction and displacement currents are extracted from the applied voltages and measured currents of AC and ns pulsed coaxial DBDs for the calculation of the power depositions and energy efficiencies through an equivalent electrical model. The discharge uniformity and operating temperature of the coaxial DBD reactor are monitored and analyzed by optical images and infrared camera. A heat conduction model is used to calculate the temperature of the internal quartz tube. It is found that the ns pulsed coaxial DBD has a much higher instantaneous power deposition in plasma, a lower total power consumption, and a higher energy efficiency compared with that excited by AC power and is more homogeneous and stable. The temperature of the outside wall of the AC and ns pulse excited coaxial DBD reaches 158 °C and 64.3 °C after 900 s operation, respectively. The experimental results on the comparison of the discharge characteristics of coaxial DBDs excited by different powers are significant for understanding of the mechanism of DBDs, reducing energy loss, and optimizing the performance of coaxial DBD in industrial applications.

  8. A Randomised Clinical Trial to Compare Coaxial and Noncoaxial Techniques in Percutaneous Core Needle Biopsy of Renal Parenchyma

    International Nuclear Information System (INIS)

    Babaei Jandaghi, Ali; Lebady, Mohammadkazem; Zamani, Athar-Alsadat; Heidarzadeh, Abtin; Monfared, Ali; Pourghorban, Ramin

    2017-01-01

    PurposeTo compare the coaxial and noncoaxial techniques of renal parenchymal core needle biopsy.Materials and MethodsThis is an institutional review board-approved randomised controlled trial comparing 83 patients (male, n = 49) who underwent renal parenchymal core biopsy with coaxial method and 83 patients (male, n = 40) with noncoaxial method. The rate of complications, the number of glomerular profiles, and the procedural time were evaluated in a comparison of the two methods. Correlation between the presence of renal parenchymal disease and the rate of complication was also evaluated.ResultsThe procedural time was significantly shorter in the coaxial technique (coaxial group, 5 ± 1 min; noncoaxial group, 14 ± 2 min; p < 0.001). The rates of complications for the coaxial method was significantly lower than the noncoaxial method (coaxial group, 10.8 %; noncoaxial group, 24.1 %; p = 0.025). There was no significant correlation between gender and the rate of complication. The number of glomerular profiles was significantly higher in patents who underwent renal biopsy with the coaxial method (coaxial group, 18.2 ± 9.1; noncoaxial group, 8.6 ± 5.5; p < 0.001). In the whole study population, the rate of complications was significantly higher in patients with a pathologic renal parenchyma compared to those with a normal parenchyma (19/71 vs. 10/95; p = 0.006).ConclusionsRenal parenchymal biopsy using a coaxial needle is a faster and safer method with a lower rate of complications.

  9. A Randomised Clinical Trial to Compare Coaxial and Noncoaxial Techniques in Percutaneous Core Needle Biopsy of Renal Parenchyma

    Energy Technology Data Exchange (ETDEWEB)

    Babaei Jandaghi, Ali [Guilan University of Medical Sciences, Department of Radiology, Poursina Hospital (Iran, Islamic Republic of); Lebady, Mohammadkazem; Zamani, Athar-Alsadat [Guilan University of Medical Sciences, Urology Research Center, Razi Hospital (Iran, Islamic Republic of); Heidarzadeh, Abtin [Guilan University of Medical Sciences, Department of Community Medicine (Iran, Islamic Republic of); Monfared, Ali [Guilan University of Medical Sciences, Urology Research Center, Razi Hospital (Iran, Islamic Republic of); Pourghorban, Ramin, E-mail: ramin-p2005@yahoo.com [Tehran University of Medical Sciences, Department of Radiology, Imam Khomeini Hospital Complex (Iran, Islamic Republic of)

    2017-01-15

    PurposeTo compare the coaxial and noncoaxial techniques of renal parenchymal core needle biopsy.Materials and MethodsThis is an institutional review board-approved randomised controlled trial comparing 83 patients (male, n = 49) who underwent renal parenchymal core biopsy with coaxial method and 83 patients (male, n = 40) with noncoaxial method. The rate of complications, the number of glomerular profiles, and the procedural time were evaluated in a comparison of the two methods. Correlation between the presence of renal parenchymal disease and the rate of complication was also evaluated.ResultsThe procedural time was significantly shorter in the coaxial technique (coaxial group, 5 ± 1 min; noncoaxial group, 14 ± 2 min; p < 0.001). The rates of complications for the coaxial method was significantly lower than the noncoaxial method (coaxial group, 10.8 %; noncoaxial group, 24.1 %; p = 0.025). There was no significant correlation between gender and the rate of complication. The number of glomerular profiles was significantly higher in patents who underwent renal biopsy with the coaxial method (coaxial group, 18.2 ± 9.1; noncoaxial group, 8.6 ± 5.5; p < 0.001). In the whole study population, the rate of complications was significantly higher in patients with a pathologic renal parenchyma compared to those with a normal parenchyma (19/71 vs. 10/95; p = 0.006).ConclusionsRenal parenchymal biopsy using a coaxial needle is a faster and safer method with a lower rate of complications.

  10. Research on a 170 GHz, 2 MW coaxial cavity gyrotron with inner-outer corrugation

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Shenyong, E-mail: houshenyong@sohu.com [Yangtze Normal University, Chongqing, 408001 (China); Yu, Sheng; Li, Hongfu [University of Electronics Science and Technology of China, Chengdu 610054 (China)

    2015-03-15

    In this paper, a coaxial cavity gyrotron with inner-outer corrugation is researched. The electron kineto-equations and the first order transmission line equations of the gyrotron are derived from Lorentz force equation and the transmission line theory, respectively. And then, a 2 MW, 170 GHz coaxial cavity gyrotron with inner-outer corrugation is designed. By means of numerical calculation, the beam-wave interaction of the coaxial cavity gyrotron with inner-outer corrugation is investigated. Results show that the efficient and the outpower of the gyrotron are 42.3% and 2.38 MW, respectively.

  11. Severe Intraoperative Hypercapnia Complicating an Unsual Malfunction of the Inner Tube of a Co-axial (BAIN'S Circuit

    Directory of Open Access Journals (Sweden)

    Youssef Emam Youssef

    2010-04-01

    Full Text Available The Bain's co-axial circuit system is fully established in general anaesthesia practice. It is favoured for its light weight and suitability for head and neck surgery. However, there are numerous published reports of malfunction of the inner tube of the Bain's co-axial circuit, with potentially lethal complications for the patient. This report presents a case in which a patient connected to a reused Bain's circuit (Datex-Ohmeda developed severe hypercapnia in the early intraoperative period due to unusual defect of the inner tube. This report tests and outlines the integrity of co-axial circuits and also reviews the available literature.

  12. Bad splits in bilateral sagittal split osteotomy: systematic review of fracture patterns.

    Science.gov (United States)

    Steenen, S A; Becking, A G

    2016-07-01

    An unfavourable and unanticipated pattern of the mandibular sagittal split osteotomy is generally referred to as a 'bad split'. Few restorative techniques to manage the situation have been described. In this article, a classification of reported bad split pattern types is proposed and appropriate salvage procedures to manage the different types of undesired fracture are presented. A systematic review was undertaken, yielding a total of 33 studies published between 1971 and 2015. These reported a total of 458 cases of bad splits among 19,527 sagittal ramus osteotomies in 10,271 patients. The total reported incidence of bad split was 2.3% of sagittal splits. The most frequently encountered were buccal plate fractures of the proximal segment (types 1A-F) and lingual fractures of the distal segment (types 2A and 2B). Coronoid fractures (type 3) and condylar neck fractures (type 4) have seldom been reported. The various types of bad split may require different salvage approaches. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  13. DETECTION OF FLUX EMERGENCE, SPLITTING, MERGING, AND CANCELLATION OF NETWORK FIELD. I. SPLITTING AND MERGING

    Energy Technology Data Exchange (ETDEWEB)

    Iida, Y.; Yokoyama, T. [Department of Earth and Planetary Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Hagenaar, H. J. [Lockheed Martin Advanced Technology Center, Org. ADBS, Building 252, 3251 Hanover Street, Palo Alto, CA 94304 (United States)

    2012-06-20

    Frequencies of magnetic patch processes on the supergranule boundary, namely, flux emergence, splitting, merging, and cancellation, are investigated through automatic detection. We use a set of line-of-sight magnetograms taken by the Solar Optical Telescope (SOT) on board the Hinode satellite. We found 1636 positive patches and 1637 negative patches in the data set, whose time duration is 3.5 hr and field of view is 112'' Multiplication-Sign 112''. The total numbers of magnetic processes are as follows: 493 positive and 482 negative splittings, 536 positive and 535 negative mergings, 86 cancellations, and 3 emergences. The total numbers of emergence and cancellation are significantly smaller than those of splitting and merging. Further, the frequency dependence of the merging and splitting processes on the flux content are investigated. Merging has a weak dependence on the flux content with a power-law index of only 0.28. The timescale for splitting is found to be independent of the parent flux content before splitting, which corresponds to {approx}33 minutes. It is also found that patches split into any flux contents with the same probability. This splitting has a power-law distribution of the flux content with an index of -2 as a time-independent solution. These results support that the frequency distribution of the flux content in the analyzed flux range is rapidly maintained by merging and splitting, namely, surface processes. We suggest a model for frequency distributions of cancellation and emergence based on this idea.

  14. The split delivery capacitated team orienteering problem

    NARCIS (Netherlands)

    Archetti, C.; Bianchessi, N.; Speranza, M. G.; Hertz, A.

    2014-01-01

    In this article, we study the capacitated team orienteering problem where split deliveries are allowed. A set of potential customers is given, each associated with a demand and a profit. The set of customers to be served by a fleet of capacitated vehicles has to be identified in such a way that the

  15. Basic dynamics of split Stirling refrigerators

    NARCIS (Netherlands)

    Waele, de A.T.A.M.; Liang, W.

    2008-01-01

    The basic features of the split Stirling refrigerator, driven by a linear compressor, are described. Friction of the compressor piston and of the regenerator, and the viscous losses due to the gas flow through the regenerator matrix are taken into account. The temp. at the cold end is an input

  16. "Split Cast Mounting: Review and New Technique".

    Science.gov (United States)

    Gundawar, S M; Pande, Neelam A; Jaiswal, Priti; Radke, U M

    2014-12-01

    For the fabrication of a prosthesis, the Prosthodontist meticulously performs all the steps. The laboratory technician then make every effort/strives to perform the remaining lab procedures. However when the processed dentures are remounted on the articulator, some changes are seen. These changes may be divided into two categories: Pre-insertion and post-insertion changes, which deal with the physical properties of the materials involved (Parker, J Prosthet Dent 31:335-342, 1974). Split cast mounting is the method of mounting casts on the articulator. It is essentially a maxillary cast constructed in two parts with a horizontal division. The procedure allows for the verification of the accuracy of the initial mounting and the ease of removal and replacement of the cast. This provides a precise means of correcting the changes in occlusion occurring as a result of the processing technique (Nogueira et al., J Prosthet Dent 91:386-388, 2004). Instability of the split mounting has always been a problem to the Prosthodontist thereby limiting its use. There are various materials mentioned in the literature. The new technique by using Dowel pins and twill thread is very easy, cheaper and simple way to stabilize the split mounting. It is useful and easy in day to day laboratory procedures. The article presents different methods of split cast mounting and the new procedure using easily available materials in prosthetic laboratory.

  17. Splitting up Beta’s change

    OpenAIRE

    Suarez, Ronny

    2014-01-01

    In this paper we estimated IBM beta from 2000 to 2013, then using differential equation mathematical formula we split up the annual beta’s change attributed to the volatility market effect, the stock volatility effect, the correlation effect and the jointly effect of these variables.

  18. Czech, Slovak science ten years after split

    CERN Multimedia

    2003-01-01

    Ten years after the split of Czechoslovakia Czech and Slovak science are facing the same difficulties: shortage of money for research, poor salaries, obsolete equipment and brain drain, especially of the young, according to a feature in the Daily Lidove Noviny (1 page).

  19. Forced splitting of fractions in CE

    NARCIS (Netherlands)

    Zalewski, D.R.; Schlautmann, Stefan; Gardeniers, Johannes G.E.

    2008-01-01

    In order to increase the electrophoretic separation between fractions of analytes on a microfluidic chip, without the need for a longer separation channel, we propose and demonstrate a preparative electrokinetic procedure by which overlapping or closely spaced fractions are automatically split. The

  20. The Split sudâmja

    Directory of Open Access Journals (Sweden)

    Petar Šimunović

    1991-12-01

    Full Text Available The name of the Split feast Sudamja!Sudajma ("festa sancti Domnii" has not yet been adequately explained. The author believes that the name originated from the Old Dalmatian adjective san(ctu + Domnĭu. In the adjective santu the cluster /an/ in front of·a consonant gave in Croatian the back nasal /q/ pronounced until the end of the 10th century and giving /u/ after that. In this way the forms *Sudumja and similar originated. The short stressed /u/ in the closed syllable was percieved by the Croatian folk as their semivowel which later gave /a/ = Sudamja. The author connects this feature with that in the toponimes Makar ( /jm/ is well known in Croatian dialectology (sumja > sujma, and it resembles the metatheses which occurs in the Split toponimes: Sukošjân > Sukojšãn ( < *santu Cassianu, Pojišân/Pojšiin (< *pasianu < Pansianu. The author finds the same feature in the toponime Dumjača (: *Dumi- + -ača. He considers these features as Croatian popular adaptations which have not occured in the personal name Dujam, the toponime Dujmovača "terrae s. Domnii" and in the adjective sandujamski, because of the link with the saint's name Domnio!Duymo etc., which has been well liked and is frequent as name of Split Romas as well as Croats from the foundation of Split, has never been broken.