Science.gov

Sample records for cyclotron beam intensity

  1. Method of enhancing cyclotron beam intensity

    DOEpatents

    Hudson, Ed D.; Mallory, Merrit L.

    1977-01-01

    When an easily ionized support gas such as xenon is added to the cold cathode in sources of the Oak Ridge Isochronous Cyclotron, large beam enhancements are produced. For example, .sup.20 Ne.sup.7+ is increased from 0.05 enA to 27 enA, and .sup.16 O.sup.5+ intensities in excess of 35 e.mu.A have been extracted for periods up to 30 minutes. Approximately 0.15 cc/min of the easily ionized support gas is supplied to the ion source through a separate gas feed line and the primary gas flow is reduced by about 30%.

  2. High intensity ion beam injection into the 88-inch cyclotron

    SciTech Connect

    Wutte, Daniela; Clark, Dave J.; Laune, Bernard; Leitner,Matthaeus A.; Lyneis, Claude M.

    2000-05-31

    Low cross section experiments to produce super-heavyelements have increased the demand for high intensity heavy ion beams atenergies of about 5 MeV/nucleon at the 88-Inch Cyclotron at the LawrenceBerkeley National Laboratory. Therefore, efforts are underway to increasethe overall ion beam transmission through the axial injection line andthe cyclotron. The ion beam emittance has been measured for various ionmasses and charge states. Beam transport simulations including spacecharge effects were performed for both of the injection line and the ionsource extraction. The relatively low nominal injection voltage of 10 kVwas found to be the main factor for ion beam losses, because of beam blowup due to space charge forces at higher intensities. Consequently,experiments and simulations have been performed at higherinjectionenergies, and it was demonstrated that the ion beams could still becentered in the cyclotron at these energies. Therefore, the new injectorion source VENUS and its ion beam transport system (currently underconstruction at the 88-Inch Cyclotron) are designed for extractionvoltages up to 30 kV.

  3. High intensity proton beam transportation through fringe field of 70 MeV compact cyclotron to beam line targets

    NASA Astrophysics Data System (ADS)

    Zhang, Xu; Li, Ming; Wei, Sumin; Xing, Jiansheng; Hu, Yueming; Johnson, Richard R.; Piazza, Leandro; Ryjkov, Vladimir

    2016-06-01

    From the stripping points, the high intensity proton beam of a compact cyclotron travels through the fringe field area of the machine to the combination magnet. Starting from there the beams with various energy is transferred to the switching magnet for distribution to the beam line targets. In the design of the extraction and transport system for the compact proton cyclotron facilities, such as the 70 MeV in France and the 100 MeV in China, the space charge effect as the beam crosses the fringe field has not been previously considered; neither has the impact on transverse beam envelope coupled from the longitudinal direction. Those have been concerned much more with the higher beam-power because of the beam loss problem. In this paper, based on the mapping data of 70 MeV cyclotron including the fringe field by BEST Cyclotron Inc (BEST) and combination magnet field by China Institute of Atomic Energy (CIAE), the beam extraction and transport are investigated for the 70 MeV cyclotron used on the SPES project at Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro (INFN-LNL). The study includes the space charge effect and longitudinal and transverse coupling mentioned above, as well as the matching of beam optics using the beam line for medical isotope production as an example. In addition, the designs of the ±45° switching magnets and the 60° bending magnet for the extracted beam with the energy from 35 MeV to 70 MeV have been made. Parts of the construction and field measurements of those magnets have been done as well. The current result shows that, the design considers the complexity of the compact cyclotron extraction area and fits the requirements of the extraction and transport for high intensity proton beam, especially at mA intensity levels.

  4. The design and construction of a pulsed beam generation system based on high intensity cyclotron

    NASA Astrophysics Data System (ADS)

    An, ShiZhong; Yin, ZhiGuo; Li, PengZhan; Song, GuoFang; Wu, LongCheng; Guan, FengPing; Xie, HuaiDong; Jia, XianLu; Lu, YinLong; Zhang, TianJue

    2011-12-01

    In order to perform the studies on a pulsed beam generation system based on a high intensity cyclotron, a test beam line with a pulsed beam generation for a 10 MeV compact cyclotron (CYCIAE-10) has been designed and constructed at China Institute of Atomic Energy (CIAE). A 70 MHz continuous H-beam can be pulsed to the pulse length of less than 10 ns with a repetition rate of 4.4 MHz. The sine waveform with a frequency of 2.2 MHz is adopted for the chopper and a mesh structure with single drift and dual gaps is used for the 70 MHz buncher. A helical resonator is designed and constructed based on simulations and experiments on the RF matching for the chopper. A helical inductance loop that is exceptionally large of its kind and equipped with water cooling for the resonator has been successfully wound and a 500 W solid RF amplifier has been manufactured. A special measuring device has been designed, which can be used to measure both the DC beam and the pulsed beam. The required pulsed beam was obtained after pulsed beam tuning.

  5. Design of the axial beam line for the injection of high intensity beams into the Laboratorio Nazionale del Sud superconducting cyclotron

    NASA Astrophysics Data System (ADS)

    Gammino, S.; Ciavola, G.

    1996-03-01

    At Laboratorio Nazionale del Sud the superconducting electron cyclotron resonance source SERSE will be used as injector for the K-800 Superconducting Cyclotron which in the future will provide the intense light ion beams to be used as primary beams for the radioactive beam project EXCYT. The goal is to inject and accelerate a few pμA of fully stripped carbon and oxygen into the cyclotron with an emittance as close as possible to the typical acceptance of the cyclotron, which should be in the order of 50π mm mrad. The study of the beam line has been carried out by taking into account both the phase space growth due to space charge and the aberrations inside the magnets. The design has been based on the results of different codes (TRANSPORT, GIOSP, PARMILA). A few details on the diagnostics will also be given. The assembly of the beam line is scheduled for the summer of 1996, just before the transfer of the source SERSE from Grenoble to Catania.

  6. High intensity beams from electron cyclotron resonance ion sources: A study of efficient extraction and transport system (invited)

    NASA Astrophysics Data System (ADS)

    Gammino, S.; Ciavola, G.; Celona, L.; Andò, L.; Passarello, S.; Zhang, X. Zh.; Spädtke, P.; Winkler, M.

    2004-05-01

    A study of the design of extraction and transport system for high intensity beams that will be produced by the next generation electron cyclotron resonance ion source (ECRIS) was carried out in the frame of a European collaboration devoted to the definition of the main parameters of third generation ECRIS. High intensity production tests carried out in the previous years at INFN-LNS have shown evidence for the need to review the main concepts of the beam analysis and transport when high currents of low energy highly charged ions are extracted from the source. The transport of such low energy beams becomes critical as soon as the total current exceeds a few mA. The study reported here is based on the calculated parameters for the GyroSERSE source and the computer simulations have been carried out to obtain low emittance beams. The design of the extraction system was carried out by means of the KOBRA (three dimensional) code. The study of the beam line has been carried out with the codes GIOS, GICO, and TRANSPORT by taking into account both the phase space growth due to space charge and to the aberrations inside the magnets. The description of some different beam line options will be also given.

  7. Intense beam production of highly charged heavy ions by the superconducting electron cyclotron resonance ion source SECRAL (invited)a)

    NASA Astrophysics Data System (ADS)

    Zhao, H. W.; Sun, L. T.; Zhang, X. Z.; Guo, X. H.; Cao, Y.; Lu, W.; Zhang, Z. M.; Yuan, P.; Song, M. T.; Zhao, H. Y.; Jin, T.; Shang, Y.; Zhan, W. L.; Wei, B. W.; Xie, D. Z.

    2008-02-01

    There has been increasing demand to provide higher beam intensity and high enough beam energy for heavy ion accelerator and some other applications, which has driven electron cyclotron resonance (ECR) ion source to produce higher charge state ions with higher beam intensity. One of development trends for highly charged ECR ion source is to build new generation ECR sources by utilization of superconducting magnet technology. SECRAL (superconducting ECR ion source with advanced design in Lanzhou) was successfully built to produce intense beams of highly charged ion for Heavy Ion Research Facility in Lanzhou (HIRFL). The ion source has been optimized to be operated at 28GHz for its maximum performance. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. An innovative design of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6T at injection, 2.2T at extraction, and a radial sextupole field of 2.0T at plasma chamber wall. During the commissioning phase at 18GHz with a stainless steel chamber, tests with various gases and some metals have been conducted with microwave power less than 3.5kW by two 18GHz rf generators. It demonstrates the performance is very promising. Some record ion beam intensities have been produced, for instance, 810eμA of O7+, 505eμA of Xe20+, 306eμA of Xe27+, and so on. The effect of the magnetic field configuration on the ion source performance has been studied experimentally. SECRAL has been put into operation to provide highly charged ion beams for HIRFL facility since May 2007.

  8. Intense beam production of highly charged heavy ions by the superconducting electron cyclotron resonance ion source SECRAL.

    PubMed

    Zhao, H W; Sun, L T; Zhang, X Z; Guo, X H; Cao, Y; Lu, W; Zhang, Z M; Yuan, P; Song, M T; Zhao, H Y; Jin, T; Shang, Y; Zhan, W L; Wei, B W; Xie, D Z

    2008-02-01

    There has been increasing demand to provide higher beam intensity and high enough beam energy for heavy ion accelerator and some other applications, which has driven electron cyclotron resonance (ECR) ion source to produce higher charge state ions with higher beam intensity. One of development trends for highly charged ECR ion source is to build new generation ECR sources by utilization of superconducting magnet technology. SECRAL (superconducting ECR ion source with advanced design in Lanzhou) was successfully built to produce intense beams of highly charged ion for Heavy Ion Research Facility in Lanzhou (HIRFL). The ion source has been optimized to be operated at 28 GHz for its maximum performance. The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping. An innovative design of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28 GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6 T at injection, 2.2 T at extraction, and a radial sextupole field of 2.0 T at plasma chamber wall. During the commissioning phase at 18 GHz with a stainless steel chamber, tests with various gases and some metals have been conducted with microwave power less than 3.5 kW by two 18 GHz rf generators. It demonstrates the performance is very promising. Some record ion beam intensities have been produced, for instance, 810 e microA of O(7+), 505 e microA of Xe(20+), 306 e microA of Xe(27+), and so on. The effect of the magnetic field configuration on the ion source performance has been studied experimentally. SECRAL has been put into operation to provide highly charged ion beams for HIRFL facility since May 2007. PMID:18315105

  9. Note: {sup 6}Li III light intensity observation for {sup 6}Li{sup 3+} ion beam operation at Hyper-Electron Cyclotron Resonance ion source

    SciTech Connect

    Muto, Hideshi; Ohshiro, Yukimitsu; Yamaka, Shoichi; Yamaguchi, Hidetoshi; Shimoura, Susumu; Watanabe, Shin-ichi; Oyaizu, Michihiro; Kobayashi, Kiyoshi; Kotaka, Yasuteru; Nishimura, Makoto; Kase, Masayuki; Kubono, Shigeru; Hattori, Toshiyuki

    2014-12-15

    The light intensity of {sup 6}Li III line spectrum at λ = 516.7 nm was observed during {sup 6}Li{sup 3+} beam tuning at the Hyper-Electron Cyclotron Resonance (ECR) ion source. Separation of ion species of the same charge to mass ratio with an electromagnetic mass analyzer is known to be an exceptionally complex process. However, {sup 6}Li III line intensity observation conducted in this study gives new insights into its simplification of this process. The light intensity of {sup 6}Li III line spectrum from the ECR plasma was found to have a strong correlation with the extracted {sup 6}Li{sup 3+} beam intensity from the RIKEN Azimuthal Varying Field cyclotron.

  10. Ion source and injection line for high intensity medical cyclotron

    SciTech Connect

    Jia, XianLu Guan, Fengping; Yao, Hongjuan; Zhang, TianJue; Yang, Jianjun; Song, Guofang; Ge, Tao; Qin, Jiuchang

    2014-02-15

    A 14 MeV high intensity compact cyclotron, CYCIAE-14, was built at China Institute of Atomic Energy (CIAE). An injection system based on the external H− ion source was used on CYCIAE-14 so as to provide high intensity beam, while most positron emission tomography cyclotrons adopt internal ion source. A beam intensity of 100 μA/14 MeV was extracted from the cyclotron with a small multi-cusp H− ion source (CIAE-CH-I type) and a short injection line, which the H− ion source of 3 mA/25 keV H− beam with emittance of 0.3π mm mrad and the injection line of with only 1.2 m from the extraction of ion source to the medial plane of the cyclotron. To increase the extracted beam intensity of the cyclotron, a new ion source (CIAE-CH-II type) of 9.1 mA was used, with maximum of 500 μA was achieved from the cyclotron. The design and test results of the ion source and injection line optimized for high intensity acceleration will be given in this paper.

  11. Development of a fast cyclotron gas stopper for intense rare isotope beams from projectile fragmentation: Study of ion extraction with a radiofrequency carpet

    SciTech Connect

    Bollen, Georg; Morrissey, David

    2011-01-16

    Research and development has been performed in support of the design of a future rare isotope beam facility in the US. An important aspect of plans for earlier RIA (Rare Isotope Accelerator) and a requirement of FRIB (Facility of Rare Isotope Beams) to be built at Michigan State University are the availability of so-called “stopped beams” for research that contributes to answering questions like how elements in the universe are created and to provide better insight into the nature of Fundamental Interactions. In order to create “stopped beams” techniques are required that transform fast rare isotopes beams as they are available directly after addresses questions like the origin of that will allow and High priority is given to the evaluation of intensity limitations and the efficiency of stopping of fast fragment beams in gas cells and to the exploration of options to increase the efficiency and the reduction of space charge effects. Systematic studies performed at MSU as part of the RIA R&D with a linear gas cell under conditions close to those expected at RIA and related simulations confirm that the efficiency of stopping and extracting ions decreases with increasing beam intensity. Similar results have also been observed at RIKEN in Japan. These results indicate the concepts presently under study will not be able to cover the full range of intensities of fast beams expected at RIA without major losses. The development of a more robust concept is therefore critical to the RIA concept. Recent new beam simulation studies performed at the NSCL show that the stopping of heavy ions in a weakly focusing gas-filled magnetic field can overcome the intensity limitation of present systems while simultaneously providing a much faster ion extraction. We propose to design and build such a cyclotron gas stopper and to test it at the NSCL under conditions as close as possible to those found at RIA.

  12. Cyclotrons for the production of radioactive beams

    SciTech Connect

    Clark, D.J.

    1990-01-01

    This paper describes the characteristics and design choices for modern cyclotrons. Cyclotrons can be used in 3 areas in the radioactive beam field: the production of high energy heavy ion beams for use in fragmentation, the spallation of targets with high energy protons, and the acceleration of radioactive beams from low energy to the MeV/u range. 16 refs., 6 figs.

  13. Influence of injection beam emittance on beam transmission efficiency in a cyclotron

    SciTech Connect

    Kurashima, Satoshi Kashiwagi, Hirotsugu; Miyawaki, Nobumasa; Yoshida, Ken-Ichi; Okumura, Susumu

    2014-02-15

    The JAEA AVF cyclotron accelerates various kinds of high-energy ion beams for research in biotechnology and materials science. Beam intensities of an ion species of the order of 10{sup −9}–10{sup −6} ampere are often required for various experiments performed sequentially over a day. To provide ion beams with sufficient intensity and stability, an operator has to retune an ion source in a short time. However, the beam intensity downstream of the cyclotron rarely increases in proportion to the intensity at the ion source. To understand the cause of this beam behavior, transmission efficiencies of a {sup 12}C{sup 5+} beam from an electron cyclotron resonance ion source to the cyclotron were measured for various conditions of the ion source. Moreover, a feasible region for acceleration in the emittance of the injection beam was clarified using a transverse-acceptance measuring system. We confirmed that the beam emittance and profile were changed depending on the condition of the ion source and that matching between the beam emittance and the acceptance of the cyclotron was degraded. However, after fine-tuning to improve the matching, beam intensity downstream of the cyclotron increased.

  14. The electromagnetic ion cyclotron beam anisotropy instability

    NASA Technical Reports Server (NTRS)

    Peter Gary, S.; Schriver, David

    1987-01-01

    Electromagnetic instabilities driven by an anisotropic, relatively cool ion beam are studied for the case in which both the beam and the instabilities propagate parallel or antiparallel to a uniform magnetic field. At modest beam-core relative drift speeds, sufficiently large perpendicular-to-parallel beam temperature ratios and sufficiently large plasma beta, the mode of fastest growth rate is the ion cyclotron beam anisotropy instability. Because the right-hand polarized waves observed upstream of slow shocks in the earth's magnetotail can lead to the appropriate beam anisotropy, the ion cyclotron instability may be present and account for the left-hand polarized magnetic waves observed there. Also, because of its relatively low phase speed, the ion cyclotron beam anisotropy instability may provide the scattering necessary for ion Fermi acceleration at slow shocks of sufficiently high plasma beta.

  15. Development of a fast scintillator based beam phase measurement system for compact superconducting cyclotrons

    SciTech Connect

    Bhattacharjee, Tanushyam; Kanti Dey, Malay; Dhara, Partha; Roy, Suvodeep; Debnath, Jayanta; Balakrishna Bhole, Rajendra; Dutta, Atanu; Pradhan, Jedidiah; Pal, Sarbajit; Pal, Gautam; Roy, Amitava; Chakrabarti, Alok

    2013-05-15

    In an isochronous cyclotron, measurements of central phase of the ion beam with respect to rf and the phase width provide a way to tune the cyclotron for maximum energy gain per turn and efficient extraction. We report here the development of a phase measurement system and the measurements carried out at the Variable Energy Cyclotron Centre's (VECC's) K= 500 superconducting cyclotron. The technique comprises detecting prompt {gamma}-rays resulting from the interaction of cyclotron ion beam with an aluminium target mounted on a radial probe in coincidence with cyclotron rf. An assembly comprising a fast scintillator and a liquid light-guide inserted inside the cyclotron was used to detect the {gamma}-rays and to transfer the light signal outside the cyclotron where a matching photo-multiplier tube was used for light to electrical signal conversion. The typical beam intensity for this measurement was a few times 10{sup 11} pps.

  16. Beam injection improvement for electron cyclotron resonance charge breeders

    SciTech Connect

    Lamy, T.; Angot, J.; Sortais, P.; Thuillier, T.

    2012-02-15

    The injection of a 1+ beam into an electron cyclotron resonance (ECR) charge breeder is classically performed through a grounded tube placed on its axis at the injection side. This tube presents various disadvantages for the operation of an ECR charge breeder. First experiments without a grounded tube show a better use of the microwave power and a better charge breeding efficiency. The optical acceptance of the charge breeder without decelerating tube allows the injection of high intensity 1+ ion beams at high energy, allowing metals sputtering inside the ion source. The use of this method for refractory metallic ion beams production is evaluated.

  17. High-intensity cyclotron for the IsoDAR experiment

    NASA Astrophysics Data System (ADS)

    Campo, D.; IsoDAR Collaboration

    2015-03-01

    The IsoDAR experiment is the MIT proposal to investigate about several neutrino properties, in order to explain some anomalies experimentally observed. It requires 10mA of proton beam at the energy of 60MeV to produce a high-intensity electron antineutrino flux from the production and the decay of 8Li: it is an ambitious goal for the accelerator design, due also to the fact that the machine has to be placed near a neutrino detector, like KAMLAND or WATCHMAN, located in underground sites. A compact cyclotron able to accelerate H2+ molecule beam up to energy of 60MeV/amu is under study. The critical issues of this machine concern the beam injection due to the effects of space charge, the efficiency of the beam extraction and the technical solutions needed to the machine assembly. Here, the innovative solutions and the preliminary results achieved by the IsoDAR team are discussed.

  18. The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole.

    PubMed

    Rodrigues, G; Becker, R; Hamm, R W; Baskaran, R; Kanjilal, D; Roy, A

    2014-02-01

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged (238)U(40+) (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam. PMID:24593474

  19. The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole

    SciTech Connect

    Rodrigues, G. Kanjilal, D.; Roy, A.; Becker, R.; Baskaran, R.

    2014-02-15

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged {sup 238}U{sup 40+} (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

  20. The direct injection of intense ion beams from a high field electron cyclotron resonance ion source into a radio frequency quadrupole

    NASA Astrophysics Data System (ADS)

    Rodrigues, G.; Becker, R.; Hamm, R. W.; Baskaran, R.; Kanjilal, D.; Roy, A.

    2014-02-01

    The ion current achievable from high intensity ECR sources for highly charged ions is limited by the high space charge. This makes classical extraction systems for the transport and subsequent matching to a radio frequency quadrupole (RFQ) accelerator less efficient. The direct plasma injection (DPI) method developed originally for the laser ion source avoids these problems and uses the combined focusing of the gap between the ion source and the RFQ vanes (or rods) and the focusing of the rf fields from the RFQ penetrating into this gap. For high performance ECR sources that use superconducting solenoids, the stray magnetic field of the source in addition to the DPI scheme provides focusing against the space charge blow-up of the beam. A combined extraction/matching system has been designed for a high performance ECR ion source injecting into an RFQ, allowing a total beam current of 10 mA from the ion source for the production of highly charged 238U40+ (1.33 mA) to be injected at an ion source voltage of 60 kV. In this design, the features of IGUN have been used to take into account the rf-focusing of an RFQ channel (without modulation), the electrostatic field between ion source extraction and the RFQ vanes, the magnetic stray field of the ECR superconducting solenoid, and the defocusing space charge of an ion beam. The stray magnetic field is shown to be critical in the case of a matched beam.

  1. A hybrid electron cyclotron resonance metal ion source with integrated sputter magnetron for the production of an intense Al+ ion beam

    NASA Astrophysics Data System (ADS)

    Weichsel, T.; Hartung, U.; Kopte, T.; Zschornack, G.; Kreller, M.; Philipp, A.

    2015-09-01

    A metal ion source prototype has been developed: a combination of magnetron sputter technology with 2.45 GHz electron cyclotron resonance (ECR) ion source technology—a so called magnetron ECR ion source (MECRIS). An integrated ring-shaped sputter magnetron with an Al target is acting as a powerful metal atom supply in order to produce an intense current of singly charged metal ions. Preliminary experiments show that an Al+ ion current with a density of 167 μA/cm2 is extracted from the source at an acceleration voltage of 27 kV. Spatially resolved double Langmuir probe measurements and optical emission spectroscopy were used to study the plasma states of the ion source: sputter magnetron, ECR, and MECRIS plasma. Electron density and temperature as well as Al atom density were determined as a function of microwave and sputter magnetron power. The effect of ECR heating is strongly pronounced in the center of the source. There the electron density is increased by one order of magnitude from 6 × 109 cm-3 to 6 × 1010 cm-3 and the electron temperature is enhanced from about 5 eV to 12 eV, when the ECR plasma is ignited to the magnetron plasma. Operating the magnetron at constant power, it was observed that its discharge current is raised from 1.8 A to 4.8 A, when the ECR discharge was superimposed with a microwave power of 2 kW. At the same time, the discharge voltage decreased from about 560 V to 210 V, clearly indicating a higher plasma density of the MECRIS mode. The optical emission spectrum of the MECRIS plasma is dominated by lines of excited Al atoms and shows a significant contribution of lines arising from singly ionized Al. Plasma emission photography with a CCD camera was used to prove probe measurements and to identify separated plasma emission zones originating from the ECR and magnetron discharge.

  2. A hybrid electron cyclotron resonance metal ion source with integrated sputter magnetron for the production of an intense Al{sup +} ion beam

    SciTech Connect

    Weichsel, T. Hartung, U.; Kopte, T.; Zschornack, G.; Kreller, M.; Philipp, A.

    2015-09-15

    A metal ion source prototype has been developed: a combination of magnetron sputter technology with 2.45 GHz electron cyclotron resonance (ECR) ion source technology—a so called magnetron ECR ion source (MECRIS). An integrated ring-shaped sputter magnetron with an Al target is acting as a powerful metal atom supply in order to produce an intense current of singly charged metal ions. Preliminary experiments show that an Al{sup +} ion current with a density of 167 μA/cm{sup 2} is extracted from the source at an acceleration voltage of 27 kV. Spatially resolved double Langmuir probe measurements and optical emission spectroscopy were used to study the plasma states of the ion source: sputter magnetron, ECR, and MECRIS plasma. Electron density and temperature as well as Al atom density were determined as a function of microwave and sputter magnetron power. The effect of ECR heating is strongly pronounced in the center of the source. There the electron density is increased by one order of magnitude from 6 × 10{sup 9} cm{sup −3} to 6 × 10{sup 10} cm{sup −3} and the electron temperature is enhanced from about 5 eV to 12 eV, when the ECR plasma is ignited to the magnetron plasma. Operating the magnetron at constant power, it was observed that its discharge current is raised from 1.8 A to 4.8 A, when the ECR discharge was superimposed with a microwave power of 2 kW. At the same time, the discharge voltage decreased from about 560 V to 210 V, clearly indicating a higher plasma density of the MECRIS mode. The optical emission spectrum of the MECRIS plasma is dominated by lines of excited Al atoms and shows a significant contribution of lines arising from singly ionized Al. Plasma emission photography with a CCD camera was used to prove probe measurements and to identify separated plasma emission zones originating from the ECR and magnetron discharge.

  3. A hybrid electron cyclotron resonance metal ion source with integrated sputter magnetron for the production of an intense Al⁺ ion beam.

    PubMed

    Weichsel, T; Hartung, U; Kopte, T; Zschornack, G; Kreller, M; Philipp, A

    2015-09-01

    A metal ion source prototype has been developed: a combination of magnetron sputter technology with 2.45 GHz electron cyclotron resonance (ECR) ion source technology-a so called magnetron ECR ion source (MECRIS). An integrated ring-shaped sputter magnetron with an Al target is acting as a powerful metal atom supply in order to produce an intense current of singly charged metal ions. Preliminary experiments show that an Al(+) ion current with a density of 167 μA/cm(2) is extracted from the source at an acceleration voltage of 27 kV. Spatially resolved double Langmuir probe measurements and optical emission spectroscopy were used to study the plasma states of the ion source: sputter magnetron, ECR, and MECRIS plasma. Electron density and temperature as well as Al atom density were determined as a function of microwave and sputter magnetron power. The effect of ECR heating is strongly pronounced in the center of the source. There the electron density is increased by one order of magnitude from 6 × 10(9) cm(-3) to 6 × 10(10) cm(-3) and the electron temperature is enhanced from about 5 eV to 12 eV, when the ECR plasma is ignited to the magnetron plasma. Operating the magnetron at constant power, it was observed that its discharge current is raised from 1.8 A to 4.8 A, when the ECR discharge was superimposed with a microwave power of 2 kW. At the same time, the discharge voltage decreased from about 560 V to 210 V, clearly indicating a higher plasma density of the MECRIS mode. The optical emission spectrum of the MECRIS plasma is dominated by lines of excited Al atoms and shows a significant contribution of lines arising from singly ionized Al. Plasma emission photography with a CCD camera was used to prove probe measurements and to identify separated plasma emission zones originating from the ECR and magnetron discharge. PMID:26429434

  4. Intense ion beam generator

    DOEpatents

    Humphries, Jr., Stanley; Sudan, Ravindra N.

    1977-08-30

    Methods and apparatus for producing intense megavolt ion beams are disclosed. In one embodiment, a reflex triode-type pulsed ion accelerator is described which produces ion pulses of more than 5 kiloamperes current with a peak energy of 3 MeV. In other embodiments, the device is constructed so as to focus the beam of ions for high concentration and ease of extraction, and magnetic insulation is provided to increase the efficiency of operation.

  5. A real-time beam-profile monitor for a PET cyclotron

    NASA Astrophysics Data System (ADS)

    Hoehr, C.; Uittenbosch, T.; Verzilov, V.; English, W.; Buckley, K.; Gray, D.; Kellog, S.; Cameron, D.; Schaffer, P.

    2012-12-01

    Beam profiles in medical cyclotrons are traditionally measured using techniques that do not provide any information about short-term fluctuations of the beam shape or beam intensity. To overcome this, we have developed a real-time harp beam profile monitor which can withstand beam power in excess of 300 W. The monitor and electronics were constructed and applied toward a 13 MeV proton beam with current of up to 25 μA. Herein are reported preliminary beam-profile measurement results.

  6. A real-time beam-profile monitor for a PET cyclotron

    SciTech Connect

    Hoehr, C.; Uittenbosch, T.; Verzilov, V.; English, W.; Buckley, K.; Gray, D.; Kellog, S.; Cameron, D.; Schaffer, P.

    2012-12-19

    Beam profiles in medical cyclotrons are traditionally measured using techniques that do not provide any information about short-term fluctuations of the beam shape or beam intensity. To overcome this, we have developed a real-time harp beam profile monitor which can withstand beam power in excess of 300 W. The monitor and electronics were constructed and applied toward a 13 MeV proton beam with current of up to 25 {mu}A. Herein are reported preliminary beam-profile measurement results.

  7. Vortex Dynamics and Shear-Layer Instability in High-Intensity Cyclotrons

    NASA Astrophysics Data System (ADS)

    Cerfon, Antoine J.

    2016-04-01

    We show that the space-charge dynamics of high-intensity beams in the plane perpendicular to the magnetic field in cyclotrons is described by the two-dimensional Euler equations for an incompressible fluid. This analogy with fluid dynamics gives a unified and intuitive framework to explain the beam spiraling and beam breakup behavior observed in experiments and in simulations. Specifically, we demonstrate that beam breakup is the result of a classical instability occurring in fluids subject to a sheared flow. We give scaling laws for the instability and predict the nonlinear evolution of beams subject to it. Our work suggests that cyclotrons may be uniquely suited for the experimental study of shear layers and vortex distributions that are not achievable in Penning-Malmberg traps.

  8. Vortex Dynamics and Shear-Layer Instability in High-Intensity Cyclotrons.

    PubMed

    Cerfon, Antoine J

    2016-04-29

    We show that the space-charge dynamics of high-intensity beams in the plane perpendicular to the magnetic field in cyclotrons is described by the two-dimensional Euler equations for an incompressible fluid. This analogy with fluid dynamics gives a unified and intuitive framework to explain the beam spiraling and beam breakup behavior observed in experiments and in simulations. Specifically, we demonstrate that beam breakup is the result of a classical instability occurring in fluids subject to a sheared flow. We give scaling laws for the instability and predict the nonlinear evolution of beams subject to it. Our work suggests that cyclotrons may be uniquely suited for the experimental study of shear layers and vortex distributions that are not achievable in Penning-Malmberg traps. PMID:27176525

  9. Cyclotron axial ion-beam-buncher system

    SciTech Connect

    Hamm, R.W.; Swenson, D.A.; Wangler, T.P.

    1982-02-11

    Adiabatic ion bunching is achieved in a cyclotron axial ion injection system through the incorporation of a radio frequency quadrupole system, which receives ions from an external ion source via an accelerate-decelerate system and a focusing einzel lens system, and which adiabatically bunches and then injects the ions into the median plane of a cyclotron via an electrostatic quadrupole system and an inflection mirror.

  10. Ion-beam-driven electrostatic ion cyclotron instabilities

    SciTech Connect

    Miura, A.; Okuda, H.; Ashour-Abdalla, M.

    1982-10-01

    We present results of numerical simulations on the electrostatic ion cyclotron instabilities driven by the ion beam parallel to the magnetic field. For the beam speed exceeding the thermal speed of background ions and the beam temperature much lower than the background ion temperature, it is found that the instability results in strong perpendicular heating and slowing down of parallel drift of the beam ions, leading to the saturation of the instability. Applications to plasma heating and space plasma physics are discussed.

  11. Production of a highly charged uranium ion beam with RIKEN superconducting electron cyclotron resonance ion source

    SciTech Connect

    Higurashi, Y.; Ohnishi, J.; Nakagawa, T.; Haba, H.; Fujimaki, M.; Komiyama, M.; Kamigaito, O.; Tamura, M.; Aihara, T.; Uchiyama, A.

    2012-02-15

    A highly charged uranium (U) ion beam is produced from the RIKEN superconducting electron cyclotron resonance ion source using 18 and 28 GHz microwaves. The sputtering method is used to produce this U ion beam. The beam intensity is strongly dependent on the rod position and sputtering voltage. We observe that the emittance of U{sup 35+} for 28 GHz microwaves is almost the same as that for 18 GHz microwaves. It seems that the beam intensity of U ions produced using 28 GHz microwaves is higher than that produced using 18 GHz microwaves at the same Radio Frequency (RF) power.

  12. Enhancement of beam pulse controllability for a single-pulse formation system of a cyclotron.

    PubMed

    Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Okumura, Susumu; Taguchi, Mitsumasa; Fukuda, Mitsuhiro

    2015-07-01

    The single-pulse formation technique using a beam chopping system consisting of two types of high-voltage beam kickers was improved to enhance the quality and intensity of the single-pulse beam with a pulse interval over 1 μs at the Japan Atomic Energy Agency cyclotron facility. A contamination rate of neighboring beam bunches in the single-pulse beam was reduced to less than 0.1%. Long-term purification of the single pulse beam was guaranteed by the well-controlled magnetic field stabilization system for the cyclotron magnet. Reduction of the multi-turn extraction number for suppressing the neighboring beam bunch contamination was achieved by restriction of a beam phase width and precise optimization of a particle acceleration phase. In addition, the single-pulse beam intensity was increased by a factor of two or more by a combination of two types of beam bunchers using sinusoidal and saw-tooth voltage waveforms. Provision of the high quality intense single-pulse beam contributed to improve the accuracy of experiments for investigation of scintillation light time-profile and for neutron energy measurement by a time-of-flight method. PMID:26233376

  13. Enhancement of beam pulse controllability for a single-pulse formation system of a cyclotron

    SciTech Connect

    Kurashima, Satoshi Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Okumura, Susumu; Taguchi, Mitsumasa; Fukuda, Mitsuhiro

    2015-07-15

    The single-pulse formation technique using a beam chopping system consisting of two types of high-voltage beam kickers was improved to enhance the quality and intensity of the single-pulse beam with a pulse interval over 1 μs at the Japan Atomic Energy Agency cyclotron facility. A contamination rate of neighboring beam bunches in the single-pulse beam was reduced to less than 0.1%. Long-term purification of the single pulse beam was guaranteed by the well-controlled magnetic field stabilization system for the cyclotron magnet. Reduction of the multi-turn extraction number for suppressing the neighboring beam bunch contamination was achieved by restriction of a beam phase width and precise optimization of a particle acceleration phase. In addition, the single-pulse beam intensity was increased by a factor of two or more by a combination of two types of beam bunchers using sinusoidal and saw-tooth voltage waveforms. Provision of the high quality intense single-pulse beam contributed to improve the accuracy of experiments for investigation of scintillation light time-profile and for neutron energy measurement by a time-of-flight method.

  14. Manipulation of the micro and macro-structure of beams extracted from cyclotrons

    SciTech Connect

    Laxdal, R.E.

    1995-09-01

    It is standard practice in cyclotrons to alter the extracted micro-pulse width by using center-region slits and/or by chopping the beam before injection. The macro-structure can also be varied by means of pulsed or sinusoidal deflection devices before injection and/or after extraction. All above methods, however, involve cutting away the unwanted beam, thus reducing the time-averaged intensity. This paper will focus on some methods used to alter the time structure of extracted beams without significant beam loss. For example radial gradients in the accelerating fields from rf cavities can be utilized to compress, expand or even split longitudinally the circulating particle bunches. The macro-structure of the extracted beam can be altered by employing resonant extraction methods and replacing the static magnetic bump with either a pulsed or a sinusoidal transverse perturbation. The methods are most suitable for H cyclotrons but may also be considered in a limited scope for cyclotrons using direct extraction. Results of computer simulations and beam tests on the TRIUMF 500 MeV H{sup {minus}} cyclotron will be presented.

  15. Neutral particle beam intensity controller

    DOEpatents

    Dagenhart, W.K.

    1984-05-29

    The neutral beam intensity controller is based on selected magnetic defocusing of the ion beam prior to neutralization. The defocused portion of the beam is dumped onto a beam dump disposed perpendicular to the beam axis. Selective defocusing is accomplished by means of a magnetic field generator disposed about the neutralizer so that the field is transverse to the beam axis. The magnetic field intensity is varied to provide the selected partial beam defocusing of the ions prior to neutralization. The desired focused neutral beam portion passes along the beam path through a defining aperture in the beam dump, thereby controlling the desired fraction of neutral particles transmitted to a utilization device without altering the kinetic energy level of the desired neutral particle fraction. By proper selection of the magnetic field intensity, virtually zero through 100% intensity control of the neutral beam is achieved.

  16. Production of high intensity 48Ca for the 88-Inch Cyclotron and other updates

    NASA Astrophysics Data System (ADS)

    Benitez, J. Y.; Franzen, K. Y.; Hodgkinson, A.; Lyneis, C. M.; Strohmeier, M.; Thullier, T.; Todd, D.; Xie, D.

    2014-02-01

    Recently the Versatile ECR for NUclear Science (VENUS) ion source was engaged in a 60-day long campaign to deliver high intensity 48Ca11+ beam to the 88-Inch Cyclotron. As the first long term use of VENUS for multi-week heavy-element research, new methods were developed to maximize oven to target efficiency. First, the tuning parameters of VENUS for injection into the cyclotron proved to be very different than those used to tune VENUS for maximum beam output of the desired charge state immediately following its bending magnet. Second, helium with no oxygen support gas was used to maximize the efficiency. The performance of VENUS and its low temperature oven used to produce the stable requested 75 eμA of 48Ca11+ beam current was impressive. The consumption of 48Ca in VENUS using the low temperature oven was checked roughly weekly, and was found to be on average 0.27 mg/h with an ionization efficiency into the 11+ charge state of 5.0%. No degradation in performance was noted over time. In addition, with the successful operation of VENUS the 88-Inch cyclotron was able to extract a record 2 pμA of 48Ca11+, with a VENUS output beam current of 219 eμA. The paper describes the characteristics of the VENUS tune used for maximum transport efficiency into the cyclotron as well as ongoing efforts to improve the transport efficiency from VENUS into the cyclotron. In addition, we briefly present details regarding the recent successful repair of the cryostat vacuum system.

  17. Production of high intensity {sup 48}Ca for the 88-Inch Cyclotron and other updates

    SciTech Connect

    Benitez, J. Y.; Hodgkinson, A.; Lyneis, C. M. Strohmeier, M.; Thullier, T.; Todd, D.; Xie, D.; Franzen, K. Y.

    2014-02-15

    Recently the Versatile ECR for NUclear Science (VENUS) ion source was engaged in a 60-day long campaign to deliver high intensity {sup 48}Ca{sup 11+} beam to the 88-Inch Cyclotron. As the first long term use of VENUS for multi-week heavy-element research, new methods were developed to maximize oven to target efficiency. First, the tuning parameters of VENUS for injection into the cyclotron proved to be very different than those used to tune VENUS for maximum beam output of the desired charge state immediately following its bending magnet. Second, helium with no oxygen support gas was used to maximize the efficiency. The performance of VENUS and its low temperature oven used to produce the stable requested 75 eμA of {sup 48}Ca{sup 11+} beam current was impressive. The consumption of {sup 48}Ca in VENUS using the low temperature oven was checked roughly weekly, and was found to be on average 0.27 mg/h with an ionization efficiency into the 11+ charge state of 5.0%. No degradation in performance was noted over time. In addition, with the successful operation of VENUS the 88-Inch cyclotron was able to extract a record 2 pμA of {sup 48}Ca{sup 11+}, with a VENUS output beam current of 219 eμA. The paper describes the characteristics of the VENUS tune used for maximum transport efficiency into the cyclotron as well as ongoing efforts to improve the transport efficiency from VENUS into the cyclotron. In addition, we briefly present details regarding the recent successful repair of the cryostat vacuum system.

  18. Theory and simulation of the beam cyclotron instability.

    NASA Technical Reports Server (NTRS)

    Lampe, M.; Manheimer, W. M.; Mcbride, J. B.; Orens, J. H.; Papadopoulos, K.; Shanny, R.; Sudan, R. N.

    1972-01-01

    A theory of plasma beam cyclotron instability is developed on the basis of computer simulation experiments. The theory holds that at certain turbulence levels, electron cross-field diffusion which supresses the electron gyroresonances is created by turbulent wave-particle interactions in a plasma beam after a period of quasi-linear exponential development of turbulence. The stabilizing effect of Landau ion damping is noted. The behavior of cold and hot ions is discussed.

  19. Beam halo in high-intensity beams

    SciTech Connect

    Wangler, T.P. )

    1993-12-25

    In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which in projection to the 2-D phase spaces results in a 2-component beam consisting of an inner core and a diffuse outer halo. The beam-halo is of concern for a next generation of cw, high-power proton linacs that could be applied to intense neutron generators for nuclear materials processing. We describe what has been learned about beam halo and the evolution of space-charge dominated beams using numerical simulations of initial laminar beams in uniform linear focusing channels. We present initial results from a study of beam entropy for an intense space-charge dominated beam.

  20. Beam halo in high-intensity beams

    SciTech Connect

    Wangler, T.P.

    1993-06-01

    In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which in projection to the 2-D phase spaces results in a 2-component beam consisting of an inner core and a diffuse outer halo. The beam-halo is of concern for a next generation of cw, high-power proton linacs that could be applied to intense neutron generators for nuclear materials processing. The author describes what has been learned about beam halo and the evolution of space-charge dominated beams using numerical simulations of initial laminar beams in uniform linear focusing channels. Initial results are presented from a study of beam entropy for an intense space-charge dominated beam.

  1. Beam halo in high-intensity beams

    SciTech Connect

    Wangler, T.P.

    1993-01-01

    In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which in projection to the 2-D phase spaces results in a 2-component beam consisting of an inner core and a diffuse outer halo. The beam-halo is of concern for a next generation of cw, high-power proton linacs that could be applied to intense neutron generators for nuclear materials processing. The author describes what has been learned about beam halo and the evolution of space-charge dominated beams using numerical simulations of initial laminar beams in uniform linear focusing channels. Initial results are presented from a study of beam entropy for an intense space-charge dominated beam.

  2. Electromagnetic ion beam instabilities - Growth at cyclotron harmonic wave numbers

    NASA Technical Reports Server (NTRS)

    Smith, Charles W.; Gary, S. Peter

    1987-01-01

    The linear theory of electromagnetic ion beam instabilities for arbitrary angles of propagation is studied, with an emphasis on the conditions necessary to generate unstable modes at low harmonics of the ion cyclotron resonance condition. The present results extend the analysis of Smith et al. (1985). That paper considered only the plasma parameters at a time during which harmonic wave modes were observed in the earth's foreshock. The parameters of that paper are used as the basis of parametric variations here to establish the range of beam properties which may give rise to observable harmonic spectra. It is shown that the growth rates of both left-hand and right-hand cyclotron harmonic instabilities are enhanced by an increase in the beam temperature anisotropy and/or the beam speed. Decreases in the beam density and/or the core-ion beta reduce the overall growth of the cyclotron harmonic instabilities but favor the growth of these modes over the growth of the nonresonant instability and thereby enhance the observability of the harmonics.

  3. Neutral particle beam intensity controller

    DOEpatents

    Dagenhart, William K.

    1986-01-01

    A neutral beam intensity controller is provided for a neutral beam generator in which a neutral beam is established by accelerating ions from an ion source into a gas neutralizer. An amplitude modulated, rotating magnetic field is applied to the accelerated ion beam in the gas neutralizer to defocus the resultant neutral beam in a controlled manner to achieve intensity control of the neutral beam along the beam axis at constant beam energy. The rotating magnetic field alters the orbits of ions in the gas neutralizer before they are neutralized, thereby controlling the fraction of neutral particles transmitted out of the neutralizer along the central beam axis to a fusion device or the like. The altered path or defocused neutral particles are sprayed onto an actively cooled beam dump disposed perpendicular to the neutral beam axis and having a central open for passage of the focused beam at the central axis of the beamline. Virtually zero therough 100% intensity control is achieved by varying the magnetic field strength without altering the ion source beam intensity or its species yield.

  4. Note: Production of a mercury beam with an electron cyclotron resonance ion source

    SciTech Connect

    Vondrasek, R.; Pardo, R.; Scott, R.

    2013-11-15

    An electron cyclotron resonance ion source has been utilized to produce mercury beams with intensities of 4.5 eμA of {sup 202}Hg{sup 29+} and 3.0 eμA of {sup 202}Hg{sup 31+} from natural abundance mercury metal. The production technique relies on the evaporation of liquid mercury into the source plasma vacuum region and utilizes elemental mercury instead of a volatile organic compound as the neutral feed material.

  5. Electron cyclotron beam measurement system in the Large Helical Device

    SciTech Connect

    Kamio, S. Takahashi, H.; Kubo, S.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Ito, S.; Kobayashi, S.; Mizuno, Y.; Okada, K.; Osakabe, M.; Mutoh, T.

    2014-11-15

    In order to evaluate the electron cyclotron (EC) heating power inside the Large Helical Device vacuum vessel and to investigate the physics of the interaction between the EC beam and the plasma, a direct measurement system for the EC beam transmitted through the plasma column was developed. The system consists of an EC beam target plate, which is made of isotropic graphite and faces against the EC beam through the plasma, and an IR camera for measuring the target plate temperature increase by the transmitted EC beam. This system is applicable to the high magnetic field (up to 2.75 T) and plasma density (up to 0.8 × 10{sup 19} m{sup −3}). This system successfully evaluated the transmitted EC beam profile and the refraction.

  6. Spiral design and beam dynamics for a variable energy cyclotron

    SciTech Connect

    Baltz, A.J.; Chasman, C.; Thorn, C.E.

    1981-01-01

    Beam-orbit studies were performed for the conversion of the SREL synchrocyclotron magnet for use as a room temperature, multiparticle, isochronous cyclotron. Based on model magnet measurements of field profiles for 8 to 23/sup 0/K gauss hill fields, a four sector spiral pole tip design has been realized which allows all isotope species of heavy ion beams to be accelerated to required final energies. The total spiral angle of 38/sup 0/ allows injection of the beams from the MP tandem into the cyclotron through a valley. The two valey RF system of 140 kV peak accelerates beams on harmonic numbers 2, 3, 4, 6 and 10 at 14 to 21 MHz. Computer calculations indicated acceptable ..nu../sub z/, ..nu../sub r/ and phase space beam characteristics and passing of resonances for typical beams considered: /sup 16/O at 8 and 150 MeV/amu, /sup 60/Ni at 100 MeV/amu and /sup 238/U at 2.5 and 16 MeV/amu. Single turn extraction is achieved with electrostatic deflection.

  7. Intense low energy positron beams

    SciTech Connect

    Lynn, K.G.; Jacobsen, F.M.

    1993-12-31

    Intense positron beams are under development or being considered at several laboratories. Already today a few accelerator based high intensity, low brightness e{sup +} beams exist producing of the order of 10{sup 8} {minus} 10{sup 9} e{sup +}/sec. Several laboratories are aiming at high intensity, high brightness e{sup +} beams with intensities greater than 10{sup 9} e{sup +}/sec and current densities of the order of 10{sup 13} {minus} 10{sup 14} e{sup +} sec{sup {minus}} {sup 1}cm{sup {minus}2}. Intense e{sup +} beams can be realized in two ways (or in a combination thereof) either through a development of more efficient B{sup +} moderators or by increasing the available activity of B{sup +} particles. In this review we shall mainly concentrate on the latter approach. In atomic physics the main trust for these developments is to be able to measure differential and high energy cross-sections in e{sup +} collisions with atoms and molecules. Within solid state physics high intensity, high brightness e{sup +} beams are in demand in areas such as the re-emission e{sup +} microscope, two dimensional angular correlation of annihilation radiation, low energy e{sup +} diffraction and other fields. Intense e{sup +} beams are also important for the development of positronium beams, as well as exotic experiments such as Bose condensation and Ps liquid studies.

  8. Performance of the beam chamber vacuum system of K = 500 cyclotron at Variable Energy Cyclotron Centre Kolkata

    SciTech Connect

    Pal, Gautam DuttaGupta, Anjan; Chakrabarti, Alok

    2014-07-15

    The beam chamber of Variable Energy Cyclotron Centre, Kolkata's K = 500 superconducting cyclotron is pumped by liquid helium cooled cryopanel with liquid nitrogen cooled radiation shield. Performance of the vacuum system was evaluated by cooling the cryopanel assembly with liquid nitrogen and liquid helium. Direct measurement of beam chamber pressure is quite difficult because of space restrictions and the presence of high magnetic field. Pressure gauges were placed away from the beam chamber. The beam chamber pressure was evaluated using a Monte Carlo simulation software for vacuum system and compared with measurements. The details of the vacuum system, measurements, and estimation of pressure of the beam chamber are described in this paper.

  9. Multiaperture ion beam extraction from gas-dynamic electron cyclotron resonance source of multicharged ions

    SciTech Connect

    Sidorov, A.; Dorf, M.; Zorin, V.; Bokhanov, A.; Izotov, I.; Razin, S.; Skalyga, V.; Rossbach, J.; Spaedtke, P.; Balabaev, A.

    2008-02-15

    Electron cyclotron resonance ion source with quasi-gas-dynamic regime of plasma confinement (ReGIS), constructed at the Institute of Applied Physics, Russia, provides opportunities for extracting intense and high-brightness multicharged ion beams. Despite the short plasma lifetime in a magnetic trap of a ReGIS, the degree of multiple ionization may be significantly enhanced by the increase in power and frequency of the applied microwave radiation. The present work is focused on studying the intense beam quality of this source by the pepper-pot method. A single beamlet emittance measured by the pepper-pot method was found to be {approx}70 {pi} mm mrad, and the total extracted beam current obtained at 14 kV extraction voltage was {approx}25 mA. The results of the numerical simulations of ion beam extraction are found to be in good agreement with experimental data.

  10. Intensity-symmetric Airy beams.

    PubMed

    Vaveliuk, P; Lencina, Alberto; Rodrigo, Jose A; Martnez-Matos, Ó

    2015-03-01

    Theoretical, numerical, and experimental research on a novel family of Airy beams in rectangular coordinates having a symmetric transverse pattern of light intensity is presented. The intensity-symmetric Airy beams include both the symmetric Airy beam whose field amplitude is an even function of the transverse coordinates and the antisymmetric Airy beam whose field amplitude is an odd function of such coordinates. The theoretical foundations are based on the relationship of the symmetries of the spectral phase with the cosine and sine Fourier transforms. These beams are analyzed in a propagation range also including the region preceding the Fourier plane. These beams exhibit autofocusing, collapse, self-bending, and reversal propagation. Moreover, the intensity distribution is strongly asymmetric with respect to the Fourier plane. All these peculiar features were not reported for other classes of paraxial beams in a rectangular frame. The experimental generation of intensity-symmetric Airy beams is demonstrated supporting the theoretical predictions. Possible applications in planar waveguide writing and optical trapping are also discussed. PMID:26366655

  11. SUPERCONDUCTING RING CYCLOTRON FOR RIKEN RI BEAM FACTORY IN JAPAN

    SciTech Connect

    Okuno, H.; Dantsuka, T.; Yamada, K.; Kase, M.; Maie, T.; Kamigaito, O.

    2010-04-09

    Since 1997, RIKEN Nishina Center has been constructing the Radioactive Isotope Beam Factory (RIBF) and succeeded in beam commissioning of its accelerator complex at the end of 2006. The world's first superconducting ring cyclotron (SRC) is the final booster in the RIBF accelerator complex which is able to accelerate all-element heavy ions to a speed of about 70% of the velocity of light. The ring cyclotron consists of 6 major superconducting sector magnets with a maximum field of 3.8 T. The total stored energy is 235 MJ, and its overall sizes are 19 m diameter, 8 m height and 8,300 tons. The magnet system assembly was completed in August 2005, and successfully reached the maximum field in November 2005. The first beam was extracted at the end of 2006 and the first uranium beam was extracted in March 2007. However operation of the helium refrigerator was not satisfactory although the commissioning of SRC was successful. Operation was stopped every two month due to degradation of its cooling power. In February 2008 the reason of the degradation was revealed to be oil contamination. Operation of the cryogenic system was restarted from August 2008 after hard task to clean up the helium refrigerator and to add oil separators to the compressor. After restoration long-term steady operation to keep the magnet superconducting continued for about 8 months with no sign of degradation of cooling capacity.

  12. The new bern PET cyclotron, its research beam line, and the development of an innovative beam monitor detector

    SciTech Connect

    Braccini, Saverio

    2013-04-19

    The new Bern cyclotron laboratory aims at industrial radioisotope production for PET diagnostics and multidisciplinary research by means of a specifically conceived beam transfer line, terminated in a separate bunker. In this framework, an innovative beam monitor detector based on doped silica and optical fibres has been designed, constructed, and tested. Scintillation light produced by Ce and Sb doped silica fibres moving across the beam is measured, giving information on beam position, shape, and intensity. The doped fibres are coupled to commercial optical fibres, allowing the read-out of the signal far away from the radiation source. This general-purpose device can be easily adapted for any accelerator used in medical applications and is suitable either for low currents used in hadrontherapy or for currents up to a few {mu}A for radioisotope production, as well as for both pulsed and continuous beams.

  13. Intense positron beam at KEK

    NASA Astrophysics Data System (ADS)

    Kurihara, Toshikazu; Yagishita, Akira; Enomoto, Atsushi; Kobayashi, Hitoshi; Shidara, Tetsuo; Shirakawa, Akihiro; Nakahara, Kazuo; Saitou, Haruo; Inoue, Kouji; Nagashima, Yasuyuki; Hyodo, Toshio; Nagai, Yasuyoshi; Hasegawa, Masayuki; Inoue, Yoshi; Kogure, Yoshiaki; Doyama, Masao

    2000-08-01

    A positron beam is a useful probe for investigating the electronic states in solids, especially concerning the surface states. The advantage of utilizing positron beams is in their simpler interactions with matter, owing to the absence of any exchange forces, in contrast to the case of low-energy electrons. However, such studies as low-energy positron diffraction, positron microscopy and positronium (Ps) spectroscopy, which require high intensity slow-positron beams, are very limited due to the poor intensity obtained from a conventional radioactive-isotope-based positron source. In conventional laboratories, the slow-positron intensity is restricted to 10 6 e +/s due to the strength of the available radioactive source. An accelerator based slow-positron source is a good candidate for increasing the slow-positron intensity. One of the results using a high intensity pulsed positron beam is presented as a study of the origins of a Ps emitted from SiO 2. We also describe the two-dimensional angular correlation of annihilation radiation (2D-ACAR) measurement system with slow-positron beams and a positron microscope.

  14. An electron cyclotron resonance ion source based low energy ion beam platform.

    PubMed

    Sun, L T; Shang, Y; Ma, B H; Zhang, X Z; Feng, Y C; Li, X X; Wang, H; Guo, X H; Song, M T; Zhao, H Y; Zhang, Z M; Zhao, H W; Xie, D Z

    2008-02-01

    To satisfy the requirements of surface and atomic physics study in the field of low energy multiple charge state ion incident experiments, a low energy (10 eV/q-20 keV/q) ion beam platform is under design at IMP. A simple test bench has been set up to test the ion beam deceleration systems. Considering virtues such as structure simplicity, easy handling, compactness, cost saving, etc., an all-permanent magnet ECRIS LAPECR1 [Lanzhou all-permanent magnet electron cyclotron resonance (ECR) ion source No. 1] working at 14.5 GHz has been adopted to produce intense medium and low charge state ion beams. LAPECR1 source has already been ignited. Some intense low charge state ion beams have been produced on it, but the first test also reveals that many problems are existing on the ion beam transmission line. The ion beam transmission mismatches result in the depressed performance of LAPECR1, which will be discussed in this paper. To obtain ultralow energy ion beam, after being analyzed by a double-focusing analyzer magnet, the selected ion beam will be further decelerated by two afocal deceleration lens systems, which is still under design. This design has taken into consideration both ions slowing down and also ion beam focusing. In this paper, the conceptual design of deceleration system will be discussed. PMID:18315202

  15. Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS.

    PubMed

    Thomae, R; Conradie, J; Fourie, D; Mira, J; Nemulodi, F; Kuechler, D; Toivanen, V

    2016-02-01

    At iThemba Laboratory for Accelerator Based Sciences (iThemba LABS) an electron cyclotron ion source was installed and commissioned. This source is a copy of the Grenoble Test Source (GTS) for the production of highly charged ions. The source is similar to the GTS-LHC at CERN and named GTS2. A collaboration between the Accelerators and Beam Physics Group of CERN and the Accelerator and Engineering Department of iThemba LABS was proposed in which the development of high intensity argon and xenon beams is envisaged. In this paper, we present beam experiments with the GTS2 at iThemba LABS, in which the results of continuous wave and afterglow operation of xenon ion beams with oxygen as supporting gases are presented. PMID:26931949

  16. Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS

    NASA Astrophysics Data System (ADS)

    Thomae, R.; Conradie, J.; Fourie, D.; Mira, J.; Nemulodi, F.; Kuechler, D.; Toivanen, V.

    2016-02-01

    At iThemba Laboratory for Accelerator Based Sciences (iThemba LABS) an electron cyclotron ion source was installed and commissioned. This source is a copy of the Grenoble Test Source (GTS) for the production of highly charged ions. The source is similar to the GTS-LHC at CERN and named GTS2. A collaboration between the Accelerators and Beam Physics Group of CERN and the Accelerator and Engineering Department of iThemba LABS was proposed in which the development of high intensity argon and xenon beams is envisaged. In this paper, we present beam experiments with the GTS2 at iThemba LABS, in which the results of continuous wave and afterglow operation of xenon ion beams with oxygen as supporting gases are presented.

  17. Influence of static electron beam`s self-fields on the cyclotron-undulator resonance

    SciTech Connect

    Rozanov, N.E.; Golub, Yu.Ya. |

    1995-12-31

    When undulators with a leading magnetic field B are used, the regime of double resonance is possible in which an undulator period is equal to an electron cyclotron wavelength. In the vicinity of this resonance an amplitude of particle oscillations in the undulator strongly depends on a difference between B and a resonant value of the leading magnetic field. Consequently, it is important to investigate a role of self-fields of the electron beam, in particular, due to its influence on the electron cyclotron wavelength. At the paper analytically and by numerical simulation the influence of the static fields of the annular electron beam on its dynamics in the axisymmetrical magnetic undulator with the leading magnetic field in the vicinity of the cyclotron-undulator resonance is investigated. It is shown that the value of the resonant magnetic field is changed with the rise of beam`s current. A shift of the resonant magnetic field may be both to larger values of B and to smaller ones, when different values of beam and waveguide radii, beam energy and undulator period are considered. A width of the resonance (on B - scale) is increased with the beam current.

  18. All-magnetic extraction for cyclotron beam reacceleration

    DOEpatents

    Hudson, E.D.; Mallory, M.L.

    1975-07-22

    An isochronous cyclotron can be modified to provide an initial electron stripping stage, a complete acceleration of the stripped ions through the cyclotron to a first energy state, means for returning the ions to an intermediate cyclotron orbit through a second stripping stage, further acceleration of the now higher energy stripped ions through the cyclotron to their final energy, and final extraction of the ions from the cyclotron. (auth)

  19. Production of beams from solid materials at Center for Nuclear Study electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Ohshiro, Y.; Yamaka, S.; Watanabe, S.; Kobayashi, K.; Kotaka, Y.; Nishimura, M.; Kase, M.; Muto, H.; Yamaguchi, H.; Shimoura, S.

    2014-02-01

    Two methods for the feed of vapor from solid materials in the Center for Nuclear Study ECR ion source are described. A rod placed near the wall of the plasma chamber, operating up to a melting point of 2600 °C, has been used for CaO, SiO2, and FeO. An oven with a number of openings, operating up to 800 °C, has been used for P2O5, Li, and S. Typical ion beam intensities of 7Li2+, 6Li3+, 40Ca12+, and 56Fe15+ are achieved 280, 75, 28, and 7 eμA, respectively. High intensity heavy ion beams are stably supplied into the azimuthally varying field cyclotron.

  20. Coherent and Tunable Terahertz Radiation from Graphene Surface Plasmon Polarirons Excited by Cyclotron Electron Beam.

    PubMed

    Zhao, Tao; Gong, Sen; Hu, Min; Zhong, Renbin; Liu, Diwei; Chen, Xiaoxing; Zhang, Ping; Wang, Xinran; Zhang, Chao; Wu, Peiheng; Liu, Shenggang

    2015-01-01

    Terahertz (THz) radiation can revolutionize modern science and technology. To this date, it remains big challenges to develop intense, coherent and tunable THz radiation sources that can cover the whole THz frequency region either by means of only electronics (both vacuum electronics and semiconductor electronics) or of only photonics (lasers, for example, quantum cascade laser). Here we present a mechanism which can overcome these difficulties in THz radiation generation. Due to the natural periodicity of 2π of both the circular cylindrical graphene structure and cyclotron electron beam (CEB), the surface plasmon polaritions (SPPs) dispersion can cross the light line of dielectric, making transformation of SPPs into radiation immediately possible. The dual natural periodicity also brings significant excellences to the excitation and the transformation. The fundamental and hybrid SPPs modes can be excited and transformed into radiation. The excited SPPs propagate along the cyclotron trajectory together with the beam and gain energy from the beam continuously. The radiation density is enhanced over 300 times, up to 10(5) W/cm(2). The radiation frequency can be widely tuned by adjusting the beam energy or chemical potential. This mechanism opens a way for developing desired THz radiation sources to cover the whole THz frequency regime. PMID:26525516

  1. Coherent and Tunable Terahertz Radiation from Graphene Surface Plasmon Polarirons Excited by Cyclotron Electron Beam

    NASA Astrophysics Data System (ADS)

    Zhao, Tao; Gong, Sen; Hu, Min; Zhong, Renbin; Liu, Diwei; Chen, Xiaoxing; Zhang, Ping; Wang, Xinran; Zhang, Chao; Wu, Peiheng; Liu, Shenggang

    2015-11-01

    Terahertz (THz) radiation can revolutionize modern science and technology. To this date, it remains big challenges to develop intense, coherent and tunable THz radiation sources that can cover the whole THz frequency region either by means of only electronics (both vacuum electronics and semiconductor electronics) or of only photonics (lasers, for example, quantum cascade laser). Here we present a mechanism which can overcome these difficulties in THz radiation generation. Due to the natural periodicity of 2π of both the circular cylindrical graphene structure and cyclotron electron beam (CEB), the surface plasmon polaritions (SPPs) dispersion can cross the light line of dielectric, making transformation of SPPs into radiation immediately possible. The dual natural periodicity also brings significant excellences to the excitation and the transformation. The fundamental and hybrid SPPs modes can be excited and transformed into radiation. The excited SPPs propagate along the cyclotron trajectory together with the beam and gain energy from the beam continuously. The radiation density is enhanced over 300 times, up to 105 W/cm2. The radiation frequency can be widely tuned by adjusting the beam energy or chemical potential. This mechanism opens a way for developing desired THz radiation sources to cover the whole THz frequency regime.

  2. Coherent and Tunable Terahertz Radiation from Graphene Surface Plasmon Polarirons Excited by Cyclotron Electron Beam

    PubMed Central

    Zhao, Tao; Gong, Sen; Hu, Min; Zhong, Renbin; Liu, Diwei; Chen, Xiaoxing; Zhang, Ping; Wang, Xinran; Zhang, Chao; Wu, Peiheng; Liu, Shenggang

    2015-01-01

    Terahertz (THz) radiation can revolutionize modern science and technology. To this date, it remains big challenges to develop intense, coherent and tunable THz radiation sources that can cover the whole THz frequency region either by means of only electronics (both vacuum electronics and semiconductor electronics) or of only photonics (lasers, for example, quantum cascade laser). Here we present a mechanism which can overcome these difficulties in THz radiation generation. Due to the natural periodicity of 2π of both the circular cylindrical graphene structure and cyclotron electron beam (CEB), the surface plasmon polaritions (SPPs) dispersion can cross the light line of dielectric, making transformation of SPPs into radiation immediately possible. The dual natural periodicity also brings significant excellences to the excitation and the transformation. The fundamental and hybrid SPPs modes can be excited and transformed into radiation. The excited SPPs propagate along the cyclotron trajectory together with the beam and gain energy from the beam continuously. The radiation density is enhanced over 300 times, up to 105 W/cm2. The radiation frequency can be widely tuned by adjusting the beam energy or chemical potential. This mechanism opens a way for developing desired THz radiation sources to cover the whole THz frequency regime. PMID:26525516

  3. Means for obtaining a metal ion beam from a heavy-ion cyclotron source

    DOEpatents

    Hudson, E.D.; Mallory, M.L.

    1975-08-01

    A description is given of a modification to a cyclotron ion source used in producing a high intensity metal ion beam. A small amount of an inert support gas maintains the usual plasma arc, except that it is necessary for the support gas to have a heavy mass, e.g., xenon or krypton as opposed to neon. A plate, fabricated from the metal (or anything that can be sputtered) to be ionized, is mounted on the back wall of the ion source arc chamber and is bombarded by returning energetic low-charged gas ions that fail to cross the initial accelerating gap between the ion source and the accelerating electrode. Some of the atoms that are dislodged from the plate by the returning gas ions become ionized and are extracted as a useful beam of heavy ions. (auth)

  4. Prospects for advanced electron cyclotron resonance and electron beam ion source charge breeding methods for EURISOL

    SciTech Connect

    Delahaye, P.; Jardin, P.; Maunoury, L.; Traykov, E.; Varenne, F.; Angot, J.; Lamy, T.; Sortais, P.; Thuillier, T.; Ban, G.; Celona, L.; Lunney, D.; Choinski, J.; Gmaj, P.; Jakubowski, A.; Steckiewicz, O.; Kalvas, T.; and others

    2012-02-15

    As the most ambitious concept of isotope separation on line (ISOL) facility, EURISOL aims at producing unprecedented intensities of post-accelerated radioactive isotopes. Charge breeding, which transforms the charge state of radioactive beams from 1+ to an n+ charge state prior to post-acceleration, is a key technology which has to overcome the following challenges: high charge states for high energies, efficiency, rapidity and purity. On the roadmap to EURISOL, a dedicated R and D is being undertaken to push forward the frontiers of the present state-of-the-art techniques which use either electron cyclotron resonance or electron beam ion sources. We describe here the guidelines of this R and D.

  5. Beam intensity upgrade at Fermilab

    SciTech Connect

    Marchionni, A.; /Fermilab

    2006-07-01

    The performance of the Fermilab proton accelerator complex is reviewed. The coming into operation of the NuMI neutrino line and the implementation of slip-stacking to increase the anti-proton production rate has pushed the total beam intensity in the Main Injector up to {approx} 3 x 10{sup 13} protons/pulse. A maximum beam power of 270 kW has been delivered on the NuMI target during the first year of operation. A plan is in place to increase it to 350 kW, in parallel with the operation of the Collider program. As more machines of the Fermilab complex become available with the termination of the Collider operation, a set of upgrades are being planned to reach first 700 kW and then 1.2 MW by reducing the Main Injector cycle time and by implementing proton stacking.

  6. Cyclotron Institute Upgrade Project

    SciTech Connect

    Clark, Henry; Yennello, Sherry; Tribble, Robert

    2014-08-26

    The Cyclotron Institute at Texas A&M University has upgraded its accelerator facilities to extend research capabilities with both stable and radioactive beams. The upgrade is divided into three major tasks: (1) re-commission the K-150 (88”) cyclotron, couple it to existing beam lines to provide intense stable beams into the K-500 experimental areas and use it as a driver to produce radioactive beams; (2) develop light ion and heavy ion guides for stopping radioactive ions created with the K-150 beams; and (3) transport 1+ ions from the ion guides into a charge-breeding electron-cyclotron-resonance ion source (CB-ECR) to produce highly-charged radioactive ions for acceleration in the K-500 cyclotron. When completed, the upgraded facility will provide high-quality re-accelerated secondary beams in a unique energy range in the world.

  7. The beam commissioning of BRIF and future cyclotron development at CIAE

    NASA Astrophysics Data System (ADS)

    Zhang, Tianjue; Yang, Jianjun

    2016-06-01

    As an upgrade project of the existing HI-13 tandem accelerator facility, the Beijing Radioactive Ion-beam Facility (BRIF) is being constructed in China Institute of Atomic Energy (CIAE). This project consists of an 100 MeV proton compact cyclotron, a two-stage ISOL system, a superconducting linac booster and various experimental terminals. The beam commissioning of the cyclotron was launched by the end of 2013 and on July 4, 2014 the first 100 MeV proton beam was received on a temporary target which was positioned at the outlet of the cyclotron. The beam current was stably maintained at above 25 μA for about 9 h on July 25, 2014 and the cyclotron is now ready for providing CW proton beam on target-source for RIB production. The beam current is expected to be increased to 200-500 μA in the coming years. The installation of the ISOL system is finished and the stable ion beam test shows it can reach a mass resolution better than 10,000. It is expected to generate dozens of RIB by 100 MeV proton beam. In addition, this paper also introduces the recent progress of the pre-study of an 800 MeV, 3-4 MW separate-sector proton cyclotron, which is aimed to provide high power proton beam for various applications, such as neutron and neutrino physics, proton radiography and nuclear data measurement and ADS system.

  8. The rare isotope beams production at the Texas A and M university Cyclotron Institute

    SciTech Connect

    Tabacaru, G.; May, D. P.; Chubarian, G.; Clark, H.; Kim, G. J.; Tribble, R. E.; Arje, J.

    2013-04-19

    The Cyclotron Institute at Texas A and M initiated an upgrade project for the production of radioactive-ion beams that incorporates a light-ion guide (LIG) and a heavy-ion guide coupled (HIG) with an Electron Cyclotron Resonance Ion Source (ECRIS) constructed for charge-boosting (CB-ECRIS). This scheme is intended to produce radioactive beams suitable for injection into the K500 superconducting cyclotron. The current status of the project and details on the ion sources and devices used in the project is presented.

  9. Production of rare isotope beams at the Texas A and M University Cyclotron Institute

    SciTech Connect

    Tabacaru, G.; May, D. P.; Chubarian, G.; Clark, H.; Kim, G. J.; Tribble, R. E.; Arje, J.

    2012-02-15

    The Cyclotron Institute at Texas A and M is currently configuring a scheme for the production of radioactive-ion beams that incorporates a light-ion guide and a heavy-ion guide coupled with an electron-cyclotron-resonance ion source constructed for charge-breeding. This scheme is part of an upgrade to the facility and is intended to produce radioactive beams suitable for injection into the K500 superconducting cyclotron. The current status of the project and details on the ion sources used in the project is presented.

  10. Electron Cyclotron Maser Emissions from Evolving Fast Electron Beams

    NASA Astrophysics Data System (ADS)

    Tang, J. F.; Wu, D. J.; Chen, L.; Zhao, G. Q.; Tan, C. M.

    2016-05-01

    Fast electron beams (FEBs) are common products of solar active phenomena. Solar radio bursts are an important diagnostic tool for understanding FEBs and the solar plasma environment in which they propagate along solar magnetic fields. In particular, the evolution of the energy spectrum and velocity distribution of FEBs due to the interaction with the ambient plasma and field during propagation can significantly influence the efficiency and properties of their emissions. In this paper, we discuss the possible evolution of the energy spectrum and velocity distribution of FEBs due to energy loss processes and the pitch-angle effect caused by magnetic field inhomogeneity, and we analyze the effects of the evolution on electron-cyclotron maser (ECM) emission, which is one of the most important mechanisms for producing solar radio bursts by FEBs. Our results show that the growth rates all decrease with the energy loss factor Q, but increase with the magnetic mirror ratio σ as well as with the steepness index δ. Moreover, the evolution of FEBs can also significantly influence the fastest growing mode and the fastest growing phase angle. This leads to the change of the polarization sense of the ECM emission. In particular, our results also reveal that an FEB that undergoes different evolution processes will generate different types of ECM emission. We believe the present results to be very helpful for a more comprehensive understanding of the dynamic spectra of solar radio bursts.

  11. A real-time intercepting beam-profile monitor for a medical cyclotron

    SciTech Connect

    Hendriks, C.; Uittenbosch, T.; Cameron, D.; Kellogg, S.; Gray, D.; Buckley, K.; Schaffer, P.; Verzilov, V.; Hoehr, C.

    2013-11-15

    There is a lack of real-time continuous beam-diagnostic tools for medical cyclotrons due to high power deposition during proton irradiation. To overcome this limitation, we have developed a profile monitor that is capable of providing continuous feedback about beam shape and current in real time while it is inserted in the beam path. This enables users to optimize the beam profile and observe fluctuations in the beam over time with periodic insertion of the monitor.

  12. 150 {mu}A 18F{sup -} target and beam port upgrade for the IBA 18/9 cyclotron

    SciTech Connect

    Stokely, M. H.; Peeples, J. L.; Poorman, M. C.; Magerl, M.; Siemer, T.; Brisard, P.; Wieland, B. W.

    2012-12-19

    A high power ({approx}3 kW) target platform has been developed for the IBA 18/9 cyclotron. New designs for the airlock, collimator and target subsystems have been fabricated and deployed. The primary project goal is reliable commercial production of 18F{sup -} at 150 {mu}A or greater, while secondary goals include improving serviceability and extending service intervals relative to OEM systems. Reliable operation in a production environment has been observed at beam currents up to 140 {mu}A. Challenges include ion source lifetime and localized peaking in the beam intensity distribution.

  13. Ion beam driven resonant ion-cyclotron instability in a magnetized dusty plasma

    SciTech Connect

    Prakash, Ved; Vijayshri; Sharma, Suresh C.; Gupta, Ruby

    2014-03-15

    Electrostatic ion cyclotron waves are excited by axial ion beam in a dusty plasma via Cerenkov and slow cyclotron interaction. The dispersion relation of the instability is derived in the presence of positively/negatively charged dust grains. The minimum beam velocity needed for the excitation is estimated for different values of relative density of negatively charged dust grains. It is shown that the minimum beam velocity needed for excitation increases as the charge density carried by dust increases. Temperature of electrons and ions, charge and mass of dust grains, external static magnetic field and finite boundary of dusty plasma significantly modify the dispersion properties of these waves and play a crucial role in the growth of resonant ion cyclotron instability. The ion cyclotron modes with phase velocity comparable to the beam velocity possess a large growth rate. The maximum value of growth rate increases with the beam density and scales as the one-third power of the beam density in Cerenkov interaction and is proportional to the square root of beam density in slow cyclotron interaction.

  14. Beam experiments towards high-intensity beams in RHIC

    SciTech Connect

    Montag C.; Ahrens, L.; Brennan, J.M.; Blaskiewicz, M.; Drees, A.; Fischer, W.; Hayes, T.; Huang, H.; Mernick, K.; Robert-Demolaize, G.; Smith, K.; Than, R.; Thieberger, P.; Yip, K.; Zeno, K.; Zhang, S.Y.

    2012-05-20

    Proton bunch intensities in RHIC are planned to be increased from 2 {center_dot} 10{sup 11} to 3 {center_dot} 10{sup 11} protons per bunch to increase the luminosity, together with head-on beam-beam compensation using electron lenses. To study the feasibility of the intensity increase, beam experiments are being performed. Recent experimental results are presented.

  15. Intelligent low-level RF system by non-destructive beam monitoring device for cyclotrons

    NASA Astrophysics Data System (ADS)

    Sharifi Asadi Malafeh, M. S.; Ghergherehchi, M.; Afarideh, H.; Chai, J. S.; Yoon, Sang Kim

    2016-04-01

    The project of a 10 MeV PET cyclotron accelerator for medical diagnosis and treatment was started at Amirkabir University of Technology in 2012. The low-level RF system of the cyclotron accelerator is designed to stabilize acceleration voltage and control the resonance frequency of the cavity. In this work an Intelligent Low Level Radio Frequency Circuit or ILLRF, suitable for most AVF cyclotron accelerators, is designed using a beam monitoring device and narrow band tunable band-pass filter. In this design, the RF phase detection does not need signal processing by a microcontroller.

  16. A generalised formulation of beam-shadow measurement in spiral-sector superconducting cyclotron

    NASA Astrophysics Data System (ADS)

    Pradhan, Jedidiah; Dey, Malay Kanti; Chakrabarti, Alok

    2014-06-01

    A generalised analysis of coherent radial oscillation through shadow measurements on the beam in a spiral-sector, superconducting cyclotron is discussed here. Experimental measurements of shadow cast by one beam-probe on another have been used to study beam behaviour at different radial positions of the K500 superconducting cyclotron at this institute. The correlation of radial oscillation and shadow measurements as well as the motion of orbit centre are also described. The modulation of turn separation by coherent radial oscillation is used to estimate the oscillation amplitude and dee voltage.

  17. A CW radiofrequency ion source for production of negative hydrogen ion beams for cyclotrons

    SciTech Connect

    Kalvas, T.; Tarvainen, O.; Komppula, J.; Koivisto, H.; Tuunanen, J.; Potkins, D.; Stewart, T.; Dehnel, M. P.

    2015-04-08

    A CW 13.56 MHz radiofrequency-driven ion source RADIS for production of H{sup −} and D{sup −} beams is under development for replacing the filament-driven ion source of the MCC30/15 cyclotron. The RF ion source has a 16-pole multicusp plasma chamber, an electromagnet-based magnetic filter and an external planar spiral RF antenna behind an AlN window. The extraction is a 5-electrode system with an adjustable puller electrode voltage for optimizing the beam formation, a water-cooled electron dump electrode and an accelerating einzel lens. At 2650 W of RF power, the source produces 1 mA of H{sup −} (2.6 mA/cm{sup 2}), which is the intensity needed at injection for production of 200 µA H{sup +} with the filament-driven ion source. A simple pepperpot device has been developed for characterizing the beam emittance. Plans for improving the power efficiency with the use of a new permanent magnet front plate is discussed.

  18. Note: Effect of hot liner in producing 40,48Ca beam from RIKEN 18-GHz electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Ozeki, K.; Higurashi, Y.; Kidera, M.; Nakagawa, T.

    2015-01-01

    In order to produce a high-intensity and stable 48Ca beam from the RIKEN 18-GHz electron cyclotron resonance ion source, we have begun testing the production of a calcium beam using a micro-oven. To minimize the consumption rate of the material (48Ca), we introduced the "hot liner" method and investigated the effect of the liner on the material consumption rate. The micro-oven was first used to produce the 48Ca beam for experiments in the RIKEN radioisotope beam factory, and a stable beam could be supplied for a long time with low consumption rate.

  19. Note: Effect of hot liner in producing {sup 40,48}Ca beam from RIKEN 18-GHz electron cyclotron resonance ion source

    SciTech Connect

    Ozeki, K. Higurashi, Y.; Kidera, M.; Nakagawa, T.

    2015-01-15

    In order to produce a high-intensity and stable {sup 48}Ca beam from the RIKEN 18-GHz electron cyclotron resonance ion source, we have begun testing the production of a calcium beam using a micro-oven. To minimize the consumption rate of the material ({sup 48}Ca), we introduced the “hot liner” method and investigated the effect of the liner on the material consumption rate. The micro-oven was first used to produce the {sup 48}Ca beam for experiments in the RIKEN radioisotope beam factory, and a stable beam could be supplied for a long time with low consumption rate.

  20. A 600 MeV cyclotron for radioactive beam production

    SciTech Connect

    Clark, D.J.

    1993-05-17

    The magnetic field design for a 600 MeV proton cyclotron is described. The cyclotron has a single stage, a normal conducting magnet coil and a 9.8 m outside yoke diameter. It has 8 sectors, with a transition to 4 sectors in the center region. The magnetic field design was done using 1958 Harwell rectangular ridge system measurements and was compared with recent 3-dimensional field calculations with the program TOSCA at NSCL. The center region 4--8 sector transition focussing was also checked with TOSCA.

  1. Beam diagnostics for high intensity hadron accelerators

    NASA Astrophysics Data System (ADS)

    Ausset, Patrick; Gardès, Daniel

    2007-07-01

    High intensity hadron beam accelerators have been recently proposed and developed either for the production of high intensity secondary beams for Nuclear and Particle Physics research (EURISOL, SPIRAL2, FAIR), or Applied Physics in the field of Accelerator Driven System and waste transmutation (EUROTRANS). For these applications, high power Linear Accelerator (LINAC) are planned to produce and accelerate hadron beams up to 1 GeV. Both commissioning and operation of these accelerators require dedicated beam instrumentation able to monitor and characterize on line as completely as possible the produced beams having a power in the range of 1 MW. Beam current, transverse beam centroı¨d position and profiles and beam energy are the most important characteristics that have to be measured. Due to the high average power of the beam, nondestructive or at least minimally intercepting beam sensors are required. Beam instrumentation for IPHI (CEA/DSM and CNRS/IN2P3 collaboration) which is a high intensity proton (3 MeV, 100 mA, CW operation) injector initially designed to be a possible front end for this kind of LINAC is under realization. Beam diagnostics already under operation, developments in progress will be described and will introduce a more general description of high power beam instrumentation.

  2. Beam extraction and high stability operation of high current electron cyclotron resonance proton ion source

    SciTech Connect

    Roychowdhury, P. Mishra, L.; Kewlani, H.; Mittal, K. C.; Patil, D. S.

    2014-03-15

    A high current electron cyclotron resonance proton ion source is designed and developed for the low energy high intensity proton accelerator at Bhabha Atomic Research Centre. The plasma discharge in the ion source is stabilized by minimizing the reflected microwave power using four stub auto tuner and magnetic field. The optimization of extraction geometry is performed using PBGUNS code by varying the aperture, shape, accelerating gap, and the potential on the electrodes. While operating the source, it was found that the two layered microwave window (6 mm quartz plate and 2 mm boron nitride plate) was damaged (a fine hole was drilled) by the back-streaming electrons after continuous operation of the source for 3 h at beam current of 20–40 mA. The microwave window was then shifted from the line of sight of the back-streaming electrons and located after the water-cooled H-plane bend. In this configuration the stable operation of the high current ion source for several hours is achieved. The ion beam is extracted from the source by biasing plasma electrode, puller electrode, and ground electrode to +10 to +50 kV, −2 to −4 kV, and 0 kV, respectively. The total ion beam current of 30–40 mA is recorded on Faraday cup at 40 keV of beam energy at 600–1000 W of microwave power, 800–1000 G axial magnetic field and (1.2–3.9) × 10{sup −3} mbar of neutral hydrogen gas pressure in the plasma chamber. The dependence of beam current on extraction voltage, microwave power, and gas pressure is investigated in the range of operation of the ion source.

  3. High intensity muon beam source for neutrino beam experiments

    NASA Astrophysics Data System (ADS)

    Kamal Sayed, Hisham

    2015-09-01

    High intensity muon beams are essential for Muon accelerators like Neutrino Factories and Muon Colliders. In this study we report on a global optimization of the muon beam production and capture based on end-to-end simulations of the Muon Front End. The study includes the pion beam production target geometry, capture field profile, and forming muon beam into microbunches for further acceleration. The interplay between the transverse and longitudinal beam dynamics during the capture and transport of muon beam is evaluated and discussed. The goal of the optimization is to provide a set of design parameters that delivers high intensity muon beam that could be fit within the acceptance of a muon beam accelerator.

  4. Electron Cooling of Intense Ion Beam

    SciTech Connect

    Dietrich, J.; Kamerdjiev, V.; Maier, R.; Prasuhn, D.; Stein, J.; Stockhorst, H.; Korotaev, Yu.; Meshkov, I.; Sidorin, A.; Smirnov, A.

    2006-03-20

    Results of experimental studies of the electron cooling of a proton beam at COSY (Juelich, Germany) are presented. Intensity of the proton beam is limited by two general effects: particle loss directly after the injection and development of instability in a deep cooled ion beam. Results of the instability investigations performed at COSY during last years are presented in this report in comparison with previous results from HIMAC (Chiba, Japan) CELSIUS (Uppsala, Sweden) and LEAR (CERN). Methods of the instability suppression, which allow increasing the cooled beam intensity, are described. This work is supported by RFBR grant no. 05-02-16320 and INTAS grant no. 03-54-5584.

  5. A vertical-beam target station and high-power targetry for the cyclotron production of radionuclides with medium energy protons

    NASA Astrophysics Data System (ADS)

    Steyn, G. F.; Vermeulen, C.; Botha, A. H.; Conradie, J. L.; Crafford, J. P. A.; Delsink, J. L. G.; Dietrich, J.; du Plessis, H.; Fourie, D. T.; Kormány, Z.; van Niekerk, M. J.; Rohwer, P. F.; Stodart, N. P.; de Villiers, J. G.

    2013-11-01

    A vertical-beam target station (VBTS) is described to exploit the high-intensity proton beams delivered by the upgraded separated-sector cyclotron of iThemba LABS for the production of longer-lived, high value radionuclides such as 22Na, 68Ge and 82Sr. Aspects of the targetry are discussed as well as a beam splitter, which makes it possible to perform radionuclide production bombardments simultaneously in two irradiation vaults. With tandem targets in two stations, four targets can be bombarded simultaneously. The delivery of 66 MeV proton beams of higher intensity has been realized by installing fixed frequency, flat-top RF resonators on both the main cyclotron and an injector cyclotron. The increase in beam intensity also required new non-destructive diagnostic components in the relevant high-energy beamlines. An overview is given of the current radionuclide production target stations, their similarities and differences and the role of the VBTS in the production programme.

  6. Transport in JET H-mode Plasmas with Beam and Ion Cyclotron Heating

    SciTech Connect

    R.V. Budny, et. al.

    2012-07-13

    Ion Cyclotron (IC) Range of Frequency waves and neutral beam (NB) injection are planned for heating in ITER and other future tokamaks. It is important to understand transport in plasmas with NB and IC to plan, predict, and improve transport and confinement. Transport predictions require simulations of the heating profiles, and for this, accurate modeling of the IC and NB heating is needed.

  7. Emittance growth in intense beams

    SciTech Connect

    Wangler, T.P.; Mills, R.S.; Crandall, K.R.

    1987-03-01

    Recent progress in the study of high-current, low-emittance, charged-particle beams may have a significant influence in the design of future linear accelerators and beam-transport systems for higher brightness applications. Three space-charge-induced rms-emittance-growth mechanisms are now well established: (1) charge-density redistribution, (2) kinetic-energy exchange toward equipartitioning, and (3) coherent instabilities driven by periodic focusing systems. We report the results from a numerical simulation study of emittance in a high-current radio-frequency quadrupole (RFQ) linear accelerator, and present a new semiempirical equation for the observed emittance growth, which agrees well with the emittance growth predicted from numerical simulation codes.

  8. Asymmetric dee-voltage compensation of beam off-centering in the milan superconducting cyclotron

    SciTech Connect

    Milinkovic, Lj.; Fabrici, E.; Ostojic, R.

    1985-10-01

    An analysis of the effects of orbit off-centering on the beam extraction in the Milan superconducting cyclotron is made, and the sensitivity of axial beam loss and radial phase space distortions to beam off-centering determined for various acceleration conditions. We conclude that the first field harmonic compensation of beam off-centering is ineffective in the region of the operating diagram where the Walkinshaw resonance precedes the ..nu.. /SUB r/ =1 resonance. Asymmetric dee-voltage compensation is considered in these cases, and the domain of validity of the method determined. A semi-empirical relation for dee-voltage distribution is deduced, and the extraction efficiency discussed.

  9. BEAM HALO FORMATION IN HIGH-INTENSITY BEAMS.

    SciTech Connect

    FEDOTOV, A.V.

    2005-03-18

    Studies of beam halo became unavoidable feature of high-intensity machines where uncontrolled beam loss should be kept to extremely small level. For a well controlled stable beam such a loss is typically associated with the low density halo surrounding beam core. In order to minimize uncontrolled beam loss or improve performance of an accelerator, it is very important to understand what are the sources of halo formation in a specific machine of interest. The dominant mechanisms are, in fact, different in linear accelerators, circular machines or Energy Recovering Linacs (ERL). In this paper, we summarize basic mechanisms of halo formation in high-intensity beams and discuss their application to various types of accelerators of interest, such as linacs, rings and ERL.

  10. Short rise time intense electron beam generator

    DOEpatents

    Olson, C.L.

    1984-03-16

    A generator for producing an intense relativisitc electron beam having a subnanosecond current rise time includes a conventional generator of intense relativistic electrons feeding into a short electrically conductive drift tube including a cavity containing a working gas at a low enough pressure to prevent the input beam from significantly ionizing the working gas. Ionizing means such as a laser simultaneously ionize the entire volume of working gas in the cavity to generate an output beam having a rise time less than one nanosecond.

  11. Short rise time intense electron beam generator

    DOEpatents

    Olson, Craig L.

    1987-01-01

    A generator for producing an intense relativistic electron beam having a subnanosecond current rise time includes a conventional generator of intense relativistic electrons feeding into a short electrically conductive drift tube including a cavity containing a working gas at a low enough pressure to prevent the input beam from significantly ionizing the working gas. Ionizing means such as a laser simultaneously ionize the entire volume of working gas in the cavity to generate an output beam having a rise time less than one nanosecond.

  12. Intense ion beams accelerated by ultra-intense laser pulses

    NASA Astrophysics Data System (ADS)

    Roth, Markus; Cowan, T. E.; Gauthier, J. C.; Vehn, J. Meyer-Ter; Allen, M.; Audebert, P.; Blazevic, A.; Fuchs, J.; Geissel, M.; Hegelich, M.; Karsch, S.; Pukhov, A.; Schlegel, T.

    2002-04-01

    The discovery of intense ion beams off solid targets irradiated by ultra-intense laser pulses has become the subject of extensive international interest. These highly collimated, energetic beams of protons and heavy ions are strongly depending on the laser parameters as well as on the properties of the irradiated targets. Therefore we have studied the influence of the target conditions on laser-accelerated ion beams generated by multi-terawatt lasers. The experiments were performed using the 100 TW laser facility at Laboratoire pour l'Utilisation des Laser Intense (LULI). The targets were irradiated by pulses up to 5×1019 W/cm2 (~300 fs,λ=1.05 μm) at normal incidence. A strong dependence on the surface conditions, conductivity, shape and purity was observed. The plasma density on the front and rear surface was determined by laser interferometry. We characterized the ion beam by means of magnetic spectrometers, radiochromic film, nuclear activation and Thompson parabolas. The strong dependence of the ion beam acceleration on the conditions on the target back surface was confirmed in agreement with predictions based on the target normal sheath acceleration (TNSA) mechanism. Finally shaping of the ion beam has been demonstrated by the appropriate tailoring of the target. .

  13. Radiative trapping in intense laser beams

    NASA Astrophysics Data System (ADS)

    Kirk, J. G.

    2016-08-01

    The dynamics of electrons in counter-propagating, circularly polarized laser beams are shown to exhibit attractors whose ability to trap particles depends on the ratio of the beam intensities and a single parameter describing radiation reaction. Analytical expressions are found for the underlying limit cycles and the parameter range in which they are stable. In high-intensity optical pulses, where radiation reaction strongly modifies the trajectories, the production of collimated gamma-rays and the initiation of non-linear cascades of electron–positron pairs can be optimized by a suitable choice of the intensity ratio.

  14. Production of intense metal ion beams from ECR ion sources using the MIVOC method

    NASA Astrophysics Data System (ADS)

    Bogomolov, S. L.; Bondarchenko, A. E.; Efremov, A. A.; Kuzmenkov, K. I.; Lebedev, A. N.; Lebedev, K. V.; Lebedev, V. Ya.; Loginov, V. N.; Mironov, V. E.; Yazvitsky, N. Yu.

    2015-12-01

    The production of metal ion beams by electron cyclotron resonance (ECR) ion sources using the MIVOC (Metal Ions from Volatile Compounds) method is described. The method is based on the use of metal compounds which have high vapor pressure at room temperature, e.g., C2B10H12, Fe(C5H5)2, etc. Intense ion beams of B and Fe were produced using this method at the FLNR JINR cyclotrons. Experiments on the production of cobalt, chromium, vanadium, germanium, and hafnium ion beams were performed at the test bench of ECR ion sources. Main efforts were put into production and acceleration of 50Ti ion beams at the U-400 cyclotron. The experiments on the production of 50Ti ion beams were performed at the test bench using natural and enriched compounds of titanium (CH3)5C5Ti(CH3)3. In these experiments, 80 μA 48Ti5+ and 70 μA 48Ti11+ beam currents were obtained at different settings of the source. Following successful tests, two 3-week runs were performed with 50Ti beams at the U-400 cyclotron aimed to perform experiments on the spectroscopy of superheavy elements. The intensity of the injected 50Ti5+ beam was 50-60 μA. The source worked stably during experiments. The compound consumption rate was determined at about 2.4 mg/h, which corresponded to the 50Ti consumption of 0.6 mg/h.

  15. Magnet design and beam dynamics in computed fields for the DC-350 cyclotron

    NASA Astrophysics Data System (ADS)

    Kazarinov, N. Yu.; Sazonov, M. N.

    2008-12-01

    The DC-350 is an isochronous cyclotron designed in the Flerov Laboratory of Nuclear Reaction (FLNR). It is intended for accelerating ions with a mass-to-charge ratio A/Z within an interval of 5-10 and with an energy of 3-12 MeV/u at the extraction radius. These ion beams will be used in nuclear and applied physics experiments. The paper describes the results of a 3D magnet simulation. The cyclotron magnet and IM90 analiziting-bend magnet of the axial injection channel are studied here. The influence of correction coils on the cyclotron magnet is calculated. All magnet fields were calculated by MERMAID 3D code [1].

  16. Beam intensity increases at the intense pulsed neutron source accelerator

    SciTech Connect

    Potts, C.; Brumwell, F.; Norem, J.; Rauchas, A.; Stipp, V.; Volk, G.

    1985-01-01

    The Intense Pulsed Neutron Source (IPNS) accelerator system has managed a 40% increase in time average beam current over the last two years. Currents of up to 15.6..mu..A (3.25 x 10/sup 12/ protons at 30 Hz) have been successfully accelerated and cleanly extracted. Our high current operation demands low loss beam handling to permit hands-on maintenance. Synchrotron beam handling efficiencies of 90% are routine. A new H/sup -/ ion source which was installed in March of 1983 offered the opportunity to get above 8 ..mu..A but an instability caused unacceptable losses when attempting to operate at 10 ..mu..A and above. Simple techniques to control the instabilities were introduced and have worked well. These techniques are discussed below. Other improvements in the regulation of various power supplies have provided greatly improved low energy orbit stability and contributed substantially to the increased beam current.

  17. Nuclear astrophysics with intense photon beam

    SciTech Connect

    Shizuma, Toshiyuki

    2012-07-09

    Quasi-monochromatic photon beams generated by inverse Compton scattering of laser light with high energy electrons can be used for precise measurements of photoneutrons and resonant scattered {gamma} rays. Extremely high intensity and small energy spreading width of the photon beam expected at the ELI Nuclear Physics facility would increase the experimental sensitivities considerably. Possible photonuclear reaction measurements relevant to the p-process nucleosynthesis are discussed.

  18. Electron Cloud Cyclotron Resonances in the Presence of a Short-bunch-length Relativistic Beam

    SciTech Connect

    Celata, C.M.; Furman, Miguel A.; Vay, J.-L.; Yu, Jennifer W.

    2008-09-02

    Computer simulations using the 2D code"POSINST" were used to study the formation of the electron cloud in the wiggler section of the positron damping ring of the International Linear Collider. In order to simulate an x-y slice of the wiggler (i.e., a slice perpendicular to the beam velocity), each simulation assumed a constant vertical magnetic field. At values of the magnetic field where the cyclotron frequency was an integral multiple of the bunch frequency, and where the field strength was less than approximately 0.6 T, equilibrium average electron densities were up to three times the density found at other neighboring field values. Effects of this resonance between the bunch and cyclotron frequency are expected to be non-negligible when the beam bunch length is much less than the product of the electron cyclotron period and the beam velocity, for a beam moving at v~;;c. Details of the dynamics of the resonance are described.

  19. AGS RESONANT EXTRACTION WITH HIGH INTENSITY BEAMS.

    SciTech Connect

    AHRENS,L.; BROWN,K.; GLENN,J.W.; ROSER,T.; TSOUPAS,N.; VANASSELT,W.

    1999-03-29

    The Brookhaven AGS third integer resonant extraction system allows the AGS to provide high quality, high intensity 25.5 GeV/c proton beams simultaneously to four target stations and as many as 8 experiments. With the increasing intensities (over 7 x 10{sup 13} protons/pulse) and associated longer spill periods (2.4 to 3 seconds long), we continue to run with low losses and high quality low modulation continuous current beams.[1] Learning to extract and transport these higher intensity beams has required a process of careful modeling and experimentation. We have had to learn how to correct for various instabilities and how to better match extraction and the transport lines to the higher emittance beams being accelerated in the AGS. Techniques employed include ''RF'' methods to smooth out momentum distributions and fine structure. We will present results of detailed multi-particle tracking modeling studies which enabled us to develop a clear understanding of beam loss mechanisms in the transport and extraction process. We will report on our status, experiences, and the present understanding of the intensity limitations imposed by resonant extraction and transport to fixed target stations.

  20. Intense steady state electron beam generator

    DOEpatents

    Hershcovitch, Ady; Kovarik, Vincent J.; Prelec, Krsto

    1990-01-01

    An intense, steady state, low emittance electron beam generator is formed by operating a hollow cathode discharge plasma source at critical levels in combination with an extraction electrode and a target electrode that are operable to extract a beam of fast primary electrons from the plasma source through a negatively biased grid that is critically operated to repel bulk electrons toward the plasma source while allowing the fast primary electrons to move toward the target in the desired beam that can be successfully transported for relatively large distances, such as one or more meters away from the plasma source.

  1. Intense steady state electron beam generator

    DOEpatents

    Hershcovitch, A.; Kovarik, V.J.; Prelec, K.

    1990-07-17

    An intense, steady state, low emittance electron beam generator is formed by operating a hollow cathode discharge plasma source at critical levels in combination with an extraction electrode and a target electrode that are operable to extract a beam of fast primary electrons from the plasma source through a negatively biased grid that is critically operated to repel bulk electrons toward the plasma source while allowing the fast primary electrons to move toward the target in the desired beam that can be successfully transported for relatively large distances, such as one or more meters away from the plasma source. 2 figs.

  2. BEAM LOSS MECHANISMS IN HIGH INTENSITY LINACS

    SciTech Connect

    Plum, Michael A

    2012-01-01

    In the present operation of the Oak Ridge Spallation Neutron Source, 60-Hz, 825-us H beam pulses are accelerated to 910 MeV, and then compressed to less than a microsecond in the storage ring, to deliver 1 MW of beam power to the spallation target. The beam loss in the superconducting portion of the linac is higher than expected, and it has shown a surprising counter-intuitive correlation with quadrupole magnetic fields, with a loss minimum occurring when the quadrupoles are set to approximately half their design values. This behavior can now be explained by a recent set of experiments that show the beam loss is primarily due to intra-beam stripping. Beam halo is another important beam loss contributor, and collimation in the 2.5 MeV Medium Energy Beam Transport has proven to be an effective mitigation strategy. In this presentation, we will summarize these and other beam loss mechanisms that are important for high intensity linacs.

  3. Focusing and neutralization of intense beams

    SciTech Connect

    Yu, Simon S.; Anders, Andre; Bieniosek, F.M.; Eylon, Shmuel; Henestroza, Enrique; Roy, Prabir; Shuman, Derek; Waldron, William; Sharp, William; Rose, Dave; Welch, Dale; Efthimion, Philip; Gilson, Eric

    2003-05-01

    In heavy ion inertial confinement fusion systems, intense beams of ions must be transported from the exit of the final focus magnet system through the target chamber to hit millimeter spot sizes on the target. Effective plasma neutralization of intense ion beams through the target chamber is essential for the viability of an economically competitive heavy ion fusion power plant. The physics of neutralized drift has been studied extensively with PIC simulations. To provide quantitative comparisons of theoretical predictions with experiment, the Heavy Ion Fusion Virtual National Laboratory has completed the construction and has begun experimentation with the NTX (Neutralized Transport Experiment) as shown in Figure 1. The experiment consists of 3 phases, each with physics issues of its own. Phase 1 is designed to generate a very high brightness potassium beam with variable perveance, using a beam aperturing technique. Phase 2 consists of magnetic transport through four pulsed quadrupoles. Here, beam tuning as well as the effects of phase space dilution through higher order nonlinear fields must be understood. In Phase 3, a converging ion beam at the exit of the magnetic section is transported through a drift section with plasma sources for beam neutralization, and the final spot size is measured under various conditions of neutralization. In this paper, we present first results from all 3 phases of the experiment.

  4. Fan-beam intensity modulated proton therapy

    SciTech Connect

    Hill, Patrick; Westerly, David; Mackie, Thomas

    2013-11-15

    Purpose: This paper presents a concept for a proton therapy system capable of delivering intensity modulated proton therapy using a fan beam of protons. This system would allow present and future gantry-based facilities to deliver state-of-the-art proton therapy with the greater normal tissue sparing made possible by intensity modulation techniques.Methods: A method for producing a divergent fan beam of protons using a pair of electromagnetic quadrupoles is described and particle transport through the quadrupole doublet is simulated using a commercially available software package. To manipulate the fan beam of protons, a modulation device is developed. This modulator inserts or retracts acrylic leaves of varying thickness from subsections of the fan beam. Each subsection, or beam channel, creates what effectively becomes a beam spot within the fan area. Each channel is able to provide 0–255 mm of range shift for its associated beam spot, or stop the beam and act as an intensity modulator. Results of particle transport simulations through the quadrupole system are incorporated into the MCNPX Monte Carlo transport code along with a model of the range and intensity modulation device. Several design parameters were investigated and optimized, culminating in the ability to create topotherapy treatment plans using distal-edge tracking on both phantom and patient datasets.Results: Beam transport calculations show that a pair of electromagnetic quadrupoles can be used to create a divergent fan beam of 200 MeV protons over a distance of 2.1 m. The quadrupole lengths were 30 and 48 cm, respectively, with transverse field gradients less than 20 T/m, which is within the range of water-cooled magnets for the quadrupole radii used. MCNPX simulations of topotherapy treatment plans suggest that, when using the distal edge tracking delivery method, many delivery angles are more important than insisting on narrow beam channel widths in order to obtain conformal target coverage

  5. Fan-beam intensity modulated proton therapy

    PubMed Central

    Hill, Patrick; Westerly, David; Mackie, Thomas

    2013-01-01

    Purpose: This paper presents a concept for a proton therapy system capable of delivering intensity modulated proton therapy using a fan beam of protons. This system would allow present and future gantry-based facilities to deliver state-of-the-art proton therapy with the greater normal tissue sparing made possible by intensity modulation techniques. Methods: A method for producing a divergent fan beam of protons using a pair of electromagnetic quadrupoles is described and particle transport through the quadrupole doublet is simulated using a commercially available software package. To manipulate the fan beam of protons, a modulation device is developed. This modulator inserts or retracts acrylic leaves of varying thickness from subsections of the fan beam. Each subsection, or beam channel, creates what effectively becomes a beam spot within the fan area. Each channel is able to provide 0–255 mm of range shift for its associated beam spot, or stop the beam and act as an intensity modulator. Results of particle transport simulations through the quadrupole system are incorporated into the MCNPX Monte Carlo transport code along with a model of the range and intensity modulation device. Several design parameters were investigated and optimized, culminating in the ability to create topotherapy treatment plans using distal-edge tracking on both phantom and patient datasets. Results: Beam transport calculations show that a pair of electromagnetic quadrupoles can be used to create a divergent fan beam of 200 MeV protons over a distance of 2.1 m. The quadrupole lengths were 30 and 48 cm, respectively, with transverse field gradients less than 20 T/m, which is within the range of water-cooled magnets for the quadrupole radii used. MCNPX simulations of topotherapy treatment plans suggest that, when using the distal edge tracking delivery method, many delivery angles are more important than insisting on narrow beam channel widths in order to obtain conformal target coverage

  6. Preliminary design of a RFQ direct injection scheme for the IsoDAR high intensity H₂⁺ cyclotron.

    PubMed

    Winklehner, D; Hamm, R; Alonso, J; Conrad, J M; Axani, S

    2016-02-01

    IsoDAR (Isotope Decay-At-Rest) is a novel experiment designed to measure neutrino oscillations through ν̄(e) disappearance, thus providing a definitive search for sterile neutrinos. In order to generate the necessary anti-neutrino flux, a high intensity primary proton beam is needed. In IsoDAR, H2(+) is accelerated and is stripped into protons just before the target, to overcome space charge issues at injection. As part of the design, we have refined an old proposal to use a RFQ to axially inject bunched H2(+) ions into the driver cyclotron. This method has several advantages over a classical low energy beam transport (LEBT) design: (1) The bunching efficiency is higher than for the previously considered two-gap buncher and thus the overall injection efficiency is higher. This relaxes the constraints on the H2(+) current required from the ion source. (2) The overall length of the LEBT can be reduced. (3) The RFQ can also accelerate the ions. This enables the ion source platform high voltage to be reduced from 70 kV to 15 kV, making underground installation easier. We are presenting the preliminary RFQ design parameters and first beam dynamics simulations from the ion source to the spiral inflector entrance. PMID:26932101

  7. Preliminary design of a RFQ direct injection scheme for the IsoDAR high intensity H 2+ cyclotron

    NASA Astrophysics Data System (ADS)

    Winklehner, D.; Hamm, R.; Alonso, J.; Conrad, J. M.; Axani, S.

    2016-02-01

    IsoDAR (Isotope Decay-At-Rest) is a novel experiment designed to measure neutrino oscillations through ν ¯ e disappearance, thus providing a definitive search for sterile neutrinos. In order to generate the necessary anti-neutrino flux, a high intensity primary proton beam is needed. In IsoDAR, H 2+ is accelerated and is stripped into protons just before the target, to overcome space charge issues at injection. As part of the design, we have refined an old proposal to use a RFQ to axially inject bunched H 2+ ions into the driver cyclotron. This method has several advantages over a classical low energy beam transport (LEBT) design: (1) The bunching efficiency is higher than for the previously considered two-gap buncher and thus the overall injection efficiency is higher. This relaxes the constraints on the H 2+ current required from the ion source. (2) The overall length of the LEBT can be reduced. (3) The RFQ can also accelerate the ions. This enables the ion source platform high voltage to be reduced from 70 kV to 15 kV, making underground installation easier. We are presenting the preliminary RFQ design parameters and first beam dynamics simulations from the ion source to the spiral inflector entrance.

  8. Particle simulation of intense electron cyclotron heating and beat-wave current drive

    SciTech Connect

    Cohen, B.I.

    1987-10-12

    High-power free-electron lasers make new methods possible for heating plasmas and driving current in toroidal plasmas with electromagnetic waves. We have undertaken particle simulation studies with one and two dimensional, relativistic particle simulation codes of intense pulsed electron cyclotron heating and beat-wave current drive. The particle simulation methods here are conventional: the algorithms are time-centered, second-order-accurate, explicit, leap-frog difference schemes. The use of conventional methods restricts the range of space and time scales to be relatively compact in the problems addressed. Nevertheless, experimentally relevant simulations have been performed. 10 refs., 2 figs.

  9. CLOVERLEAF CYCLOTRON

    DOEpatents

    McMillan, E.M.; Judd, D.L.

    1959-02-01

    A cyclotron is presented embodying a unique magnetic field configuration, which configuration increases in intensity with radius and therefore compensates for the reltivistic mass effect, the field having further convolutions productive of axial stability in the particle beam. By reconciling the seemingly opposed requirements of mass increase compensation on one hand and anial stability on the other, the production of extremely high current particle beams in the relativistie energy range is made feasible. Certain further advantages inhere in the invention, notably an increase in the usable magnet gap, simplified and more efficient extraction of the beam from the accelerator, and ready adaptation to the use of multiply phased excitation as contrasted with the single phased systems herstofore utilized. General

  10. Intense diagnostic neutral beam development for ITER

    SciTech Connect

    Rej, D.J.; Henins, I.; Fonck, R.J.; Kim, Y.J.

    1992-05-01

    For the next-generation, burning tokamak plasmas such as ITER, diagnostic neutral beams and beam spectroscopy will continue to be used to determine a variety of plasma parameters such as ion temperature, rotation, fluctuations, impurity content, current density profile, and confined alpha particle density and energy distribution. Present-day low-current, long-pulse beam technology will be unable to provide the required signal intensities because of higher beam attenuation and background bremsstrahlung radiation in these larger, higher-density plasmas. To address this problem, we are developing a short-pulse, intense diagnostic neutral beam. Protons or deuterons are accelerated using magnetic-insulated ion-diode technology, and neutralized in a transient gas cell. A prototype 25-kA, 100-kV, 1-{mu}s accelerator is under construction at Los Alamos. Initial experiments will focus on ITER-related issues of beam energy distribution, current density, pulse length, divergence, propagation, impurity content, reproducibility, and maintenance.

  11. Intense diagnostic neutral beam development for ITER

    SciTech Connect

    Rej, D.J.; Henins, I. ); Fonck, R.J.; Kim, Y.J. . Dept. of Nuclear Engineering and Engineering Physics)

    1992-01-01

    For the next-generation, burning tokamak plasmas such as ITER, diagnostic neutral beams and beam spectroscopy will continue to be used to determine a variety of plasma parameters such as ion temperature, rotation, fluctuations, impurity content, current density profile, and confined alpha particle density and energy distribution. Present-day low-current, long-pulse beam technology will be unable to provide the required signal intensities because of higher beam attenuation and background bremsstrahlung radiation in these larger, higher-density plasmas. To address this problem, we are developing a short-pulse, intense diagnostic neutral beam. Protons or deuterons are accelerated using magnetic-insulated ion-diode technology, and neutralized in a transient gas cell. A prototype 25-kA, 100-kV, 1-{mu}s accelerator is under construction at Los Alamos. Initial experiments will focus on ITER-related issues of beam energy distribution, current density, pulse length, divergence, propagation, impurity content, reproducibility, and maintenance.

  12. Investigations on the structure of the extracted ion beam from an electron cyclotron resonance ion source

    SciTech Connect

    Spaedtke, P.; Lang, R.; Maeder, J.; Rossbach, J.; Tinschert, K.; Maimone, F.

    2012-02-15

    Using improved beam diagnostic tools, the structure of an ion beam extracted from an electron cyclotron resonance ion source (ECRIS) becomes visible. Especially viewing targets to display the beam profile and pepper pot devices for emittance measurements turned out to be very useful. On the contrary, diagnostic tools integrating over one space coordinate like wire harps for profile measurements or slit-slit devices, respectively slit-grid devices to measure the emittance might be applicable for beam transport investigations in a quadrupole channel, but are not very meaningful for investigations regarding the given ECRIS symmetry. Here we try to reproduce the experimentally found structure on the ion beam by simulation. For the simulation, a certain model has to be used to reproduce the experimental results. The model is also described in this paper.

  13. Transverse distribution of beam current oscillations of a 14 GHz electron cyclotron resonance ion source.

    PubMed

    Tarvainen, O; Toivanen, V; Komppula, J; Kalvas, T; Koivisto, H

    2014-02-01

    The temporal stability of oxygen ion beams has been studied with the 14 GHz A-ECR at JYFL (University of Jyvaskyla, Department of Physics). A sector Faraday cup was employed to measure the distribution of the beam current oscillations across the beam profile. The spatial and temporal characteristics of two different oscillation "modes" often observed with the JYFL 14 GHz ECRIS are discussed. It was observed that the low frequency oscillations below 200 Hz are distributed almost uniformly. In the high frequency oscillation "mode," with frequencies >300 Hz at the core of the beam, carrying most of the current, oscillates with smaller amplitude than the peripheral parts of the beam. The results help to explain differences observed between the two oscillation modes in terms of the transport efficiency through the JYFL K-130 cyclotron. The dependence of the oscillation pattern on ion source parameters is a strong indication that the mechanisms driving the fluctuations are plasma effects. PMID:24593488

  14. Dynamic cyclotron resonance in relativistic microwave devices with linear electron beams

    SciTech Connect

    Vlasov, A.N.; Kornienko, V.N.; Cherepenin, V.A. |

    1995-12-31

    In the present work the authors analyze theoretically and by numerical simulation dependencies of output radiation versus magnitude of focusing magnetic field when magnetic field magnitude is sufficiently smaller than value corresponding to cyclotron absorption. The high frequency electromagnetic field amplitude is high for optimum regimes with high efficiency level. In this case some electrons are accelerated and different electrons are decelerated during interaction inside device. As a result, cyclotron resonance conditions are different for different electron groups. The authors have found theoretically condition of dynamic cyclotron resonance when it is possible to improve efficiency of interaction in devices with distributed interaction such as TWT, BWO, generator of diffractional radiation by combination of Cherenkov and cyclotron interactions in strong nonlinear regimes with optimum efficiency levels. The numerical simulation of the interaction between initially linear electron beam and electromagnetic field show that there are regions of efficiency improvement up to 50 and amplitude of high-frequency electromagnetic field. One of the important features of such combined interaction is dependence on relativistic factor. They have found optimum region of relativistic factors by numerical simulation. The results of numerical simulation were compared with experimental data refer to relativistic diffractional generators and multiwave Cherenkov generators. Good agreement in value of optimum magnitude of guiding magnetic field was obtained.

  15. Cyclotron-undulator cooling of a free-electron-laser beam

    SciTech Connect

    Bandurkin, I. V.; Kuzikov, S. V.; Savilov, A. V.

    2014-08-18

    We propose methods of fast cooling of an electron beam, which are based on wiggling of particles in an undulator in the presence of an axial magnetic field. We use a strong dependence of the axial electron velocity on the oscillatory velocity, when the electron cyclotron frequency is close to the frequency of electron wiggling in the undulator field. The abnormal character of this dependence (when the oscillatory velocity increases with the increase of the input axial velocity) can be a basis of various methods for fast cooling of moderately relativistic (several MeV) electron beams.

  16. A kinetic cyclotron maser instability associated with a hollow beam of electrons

    NASA Technical Reports Server (NTRS)

    Wu, C. S.; Freund, H. P.

    1984-01-01

    A kinetic cyclotron maser instability associated with a hollow-beam distribution function is studied. The instability differs from that discussed for the gyrotron device in two respects: in the present case the momentum dispersion is substantial, and furthermore there exists a low-energy background plasma. On the basis of physical arguments it can be demonstrated that the hollow-beam distribution is far more unstable than the loss cone distribution which has been extensively investigated in recent years. A criterion for maximum growth rate is established on the basis of consideration of the resonance ellipse. The validity of this criterion is supported by the results of numerical calculation.

  17. Beam tracking simulation in the central region of a 13 MeV PET cyclotron

    NASA Astrophysics Data System (ADS)

    Anggraita, Pramudita; Santosa, Budi; Taufik, Mulyani, Emy; Diah, Frida Iswinning

    2012-06-01

    This paper reports the trajectories simulation of proton beam in the central region of a 13 MeV PET cyclotron, operating with negative proton beam (for easier beam extraction using a stripper foil), 40 kV peak accelerating dee voltage at fourth harmonic frequency of 77.88 MHz, and average magnetic field of 1.275 T. The central region covers fields of 240mm × 240mm × 30mm size at 1mm resolution. The calculation was also done at finer 0.25mm resolution covering fields of 30mm × 30mm × 4mm size to see the effects of 0.55mm horizontal width of the ion source window and the halted trajectories of positive proton beam. The simulations show up to 7 turns of orbital trajectories, reaching about 1 MeV of beam energy. The distribution of accelerating electric fields and magnetic fields inside the cyclotron were calculated in 3 dimension using Opera3D code and Tosca modules for static magnetic and electric fields. The trajectory simulation was carried out using Scilab 5.3.3 code.

  18. A simple method to measure proton beam energy in a standard medical cyclotron.

    PubMed

    Burrage, J W; Asad, A H; Fox, R A; Price, R I; Campbell, A M; Siddiqui, S

    2009-06-01

    A simple and rapid technique to measure the proton beam energy in the external beam line of a medical cyclotron has been examined. A stack of 0.1 mm thick high purity copper (Cu) foils was bombarded and the relative activity of 65Zn produced in each foil was compared to a computational model that predicted activity, based on proton stopping power, reaction cross-sectional data, and beam energy. In the model, the beam energy was altered iteratively until the best match between computed and measured relative activities of the stack of disks was obtained. The main advantage of this method is that it does not require the comparison of the activities of different isotopes of zinc arising from (p, xn) reactions in the Cu, which would require the gamma photon detector being calibrated for different energy responses. Using this technique the proton beam energy of a nominally 18 MeV standard isochronous medical cyclotron was measured as 17.49 +/- 0.04 (SD) MeV, with a precision of 0.2% CV. PMID:19623860

  19. Cyclotron autoresonant accelerator for electron beam dry scrubbing of flue gases

    SciTech Connect

    LaPointe, M.A.; Hirshfield, J.L.; Hirshfield, J.L.; Wang, Changbiao

    1999-06-01

    Design and construction is underway for a novel rf electron accelerator for electron beam dry scrubbing (EBDS) of flue gases emanating from fossil-fuel burners. This machine, a cyclotron autoresonance accelerator (CARA), has already shown itself capable of converting rf power to electron beam power with efficiency values as high as 96{percent}. This proof-of-principle experiment will utilize a 300 kV, 33 A Pierce type electron gun and up to 24 MW of available rf power at 2.856 GHz to produce 1.0 MeV, 33 MW electron beam pulses. The self-scanning conical beam from the high power CARA will be evaluated for EBDS and other possible environmental applications. {copyright} {ital 1999 American Institute of Physics.}

  20. Cyclotron autoresonant accelerator for electron beam dry scrubbing of flue gases

    SciTech Connect

    LaPointe, M. A.; Hirshfield, J. L.; Wang Changbiao

    1999-06-10

    Design and construction is underway for a novel rf electron accelerator for electron beam dry scrubbing (EBDS) of flue gases emanating from fossil-fuel burners. This machine, a cyclotron autoresonance accelerator (CARA), has already shown itself capable of converting rf power to electron beam power with efficiency values as high as 96%. This proof-of-principle experiment will utilize a 300 kV, 33 A Pierce type electron gun and up to 24 MW of available rf power at 2.856 GHz to produce 1.0 MeV, 33 MW electron beam pulses. The self-scanning conical beam from the high power CARA will be evaluated for EBDS and other possible environmental applications.

  1. Coherent light in intense spatiospectral twin beams

    NASA Astrophysics Data System (ADS)

    Peřina, Jan

    2016-06-01

    Intense spatio-spectral twin beams generated in the regime with pump depletion are analyzed applying a suggested quantum model that treats the signal, idler, and pump fields in the same way. The model assumes the signal and idler fields in the form of the generalized superposition of signal and noise and reveals nonzero signal coherent components in both fields, contrary to the models developed earlier. The influence of coherent components on the properties of intense twin beams is elucidated. The interference pattern formed in the process of sum-frequency generation and that of the Hong-Ou-Mandel interferometer are shown to be able to experimentally confirm the presence of coherent components.

  2. Extraction of D- beams from the cyclotron JULIC for injection into the cooler synchrotron COSY

    NASA Astrophysics Data System (ADS)

    Bräutigam, W.; Brings, R.; Gad, N.; Gebel, R.; Jungwirth, H.; Maier, R.; Rindfleisch, U.

    2001-12-01

    The cooler synchrotron COSY was intended from its inception to provide also deuteron beams which, in addition to protons, could considerably expand the range of experiments accessible at this accelerator facility. A major obstacle to deliver the required D- beams with the injector cyclotron JULIC has been its electrostatic septum deflector at extraction. After the conversion of JULIC into a negative ion machine, operation of the original deflector at the voltage levels necessary for D- extraction proved to be impossible with reversed polarity due to severe electrical strength problems like sparking and dark currents. The design and development of a suitable septum deflector turned out to be a challenging and tedious process lasting several years. The new device is in operation since January 2000 and the cyclotron was successfully tested in October for delivering D- beams at 75 MeV with an extracted current in the order of 10 μA. Development, test procedures and characteristics of the new electrostatic septum deflector are reported together with its operational performance to date. Results achieved during the first test run with D- ions are presented, including injection and acceleration of the deuteron beam in COSY.

  3. Positron microanalysis with high intensity beams

    SciTech Connect

    Hulett, L.D. Jr.; Donohue, D.L.

    1990-01-01

    One of the more common applications for a high intensity slow positron facility will be microanalysis of solid materials. In the first section of this paper some examples are given of procedures that can be developed. Since most of the attendees of this workshop are experts in positron spectroscopy, comprehensive descriptions will be omitted. With the exception of positron emission microscopy, most of the procedures will be based on those already in common use with broad beams. The utility of the methods have all been demonstrated, but material scientists use very few of them because positron microbeams are not generally available. A high intensity positron facility will make microbeams easier to obtain and partially alleviate this situation. All microanalysis techniques listed below will have a common requirement, which is the ability to locate the microscopic detail or area of interest and to focus the positron beam exclusively on it. The last section of this paper is a suggestion of how a high intensity positron facility might be designed so as to have this capability built in. The method will involve locating the specimen by scanning it with the microbeam of positrons and inducing a secondary electron image that will immediately reveal whether or not the positron beam is striking the proper portion of the specimen. This scanning positron microscope' will be a somewhat prosaic analog of the conventional SEM. It will, however, be an indispensable utility that will enhance the practicality of positron microanalysis techniques. 6 refs., 1 fig.

  4. Experimental observation of acoustic emissions generated by a pulsed proton beam from a hospital-based clinical cyclotron

    SciTech Connect

    Jones, Kevin C.; Solberg, Timothy D.; Avery, Stephen; Vander Stappen, François; Janssens, Guillaume; Prieels, Damien; Bawiec, Christopher R.; Lewin, Peter A.; Sehgal, Chandra M.

    2015-12-15

    Purpose: To measure the acoustic signal generated by a pulsed proton spill from a hospital-based clinical cyclotron. Methods: An electronic function generator modulated the IBA C230 isochronous cyclotron to create a pulsed proton beam. The acoustic emissions generated by the proton beam were measured in water using a hydrophone. The acoustic measurements were repeated with increasing proton current and increasing distance between detector and beam. Results: The cyclotron generated proton spills with rise times of 18 μs and a maximum measured instantaneous proton current of 790 nA. Acoustic emissions generated by the proton energy deposition were measured to be on the order of mPa. The origin of the acoustic wave was identified as the proton beam based on the correlation between acoustic emission arrival time and distance between the hydrophone and proton beam. The acoustic frequency spectrum peaked at 10 kHz, and the acoustic pressure amplitude increased monotonically with increasing proton current. Conclusions: The authors report the first observation of acoustic emissions generated by a proton beam from a hospital-based clinical cyclotron. When modulated by an electronic function generator, the cyclotron is capable of creating proton spills with fast rise times (18 μs) and high instantaneous currents (790 nA). Measurements of the proton-generated acoustic emissions in a clinical setting may provide a method for in vivo proton range verification and patient monitoring.

  5. Charge breeding results and future prospects with electron cyclotron resonance ion source and electron beam ion source (invited).

    PubMed

    Vondrasek, R; Levand, A; Pardo, R; Savard, G; Scott, R

    2012-02-01

    The Californium Rare Ion Breeder Upgrade (CARIBU) of the Argonne National Laboratory ATLAS facility will provide low-energy and reaccelerated neutron-rich radioactive beams for the nuclear physics program. A 70 mCi (252)Cf source produces fission fragments which are thermalized and collected by a helium gas catcher into a low-energy particle beam with a charge of 1+ or 2+. An electron cyclotron resonance (ECR) ion source functions as a charge breeder in order to raise the ion charge sufficiently for acceleration in the ATLAS linac. The final CARIBU configuration will utilize a 1 Ci (252)Cf source to produce radioactive beams with intensities up to 10(6) ions∕s for use in the ATLAS facility. The ECR charge breeder has been tested with stable beam injection and has achieved charge breeding efficiencies of 3.6% for (23)Na(8+), 15.6% for (84)Kr(17+), and 13.7% for (85)Rb(19+) with typical breeding times of 10 ms∕charge state. For the first radioactive beams, a charge breeding efficiency of 11.7% has been achieved for (143)Cs(27+) and 14.7% for (143)Ba(27+). The project has been commissioned with a radioactive beam of (143)Ba(27+) accelerated to 6.1 MeV∕u. In order to take advantage of its lower residual contamination, an EBIS charge breeder will replace the ECR charge breeder in the next two years. The advantages and disadvantages of the two techniques are compared taking into account the requirements of the next generation radioactive beam facilities. PMID:22380254

  6. Charge breeding results and future prospects with electron cyclotron resonance ion source and electron beam ion source (invited)

    SciTech Connect

    Vondrasek, R.; Levand, A.; Pardo, R.; Savard, G.; Scott, R.

    2012-02-15

    The Californium Rare Ion Breeder Upgrade (CARIBU) of the Argonne National Laboratory ATLAS facility will provide low-energy and reaccelerated neutron-rich radioactive beams for the nuclear physics program. A 70 mCi {sup 252}Cf source produces fission fragments which are thermalized and collected by a helium gas catcher into a low-energy particle beam with a charge of 1+ or 2+. An electron cyclotron resonance (ECR) ion source functions as a charge breeder in order to raise the ion charge sufficiently for acceleration in the ATLAS linac. The final CARIBU configuration will utilize a 1 Ci {sup 252}Cf source to produce radioactive beams with intensities up to 10{sup 6} ions/s for use in the ATLAS facility. The ECR charge breeder has been tested with stable beam injection and has achieved charge breeding efficiencies of 3.6% for {sup 23}Na{sup 8+}, 15.6% for {sup 84}Kr{sup 17+}, and 13.7% for {sup 85}Rb{sup 19+} with typical breeding times of 10 ms/charge state. For the first radioactive beams, a charge breeding efficiency of 11.7% has been achieved for {sup 143}Cs{sup 27+} and 14.7% for {sup 143}Ba{sup 27+}. The project has been commissioned with a radioactive beam of {sup 143}Ba{sup 27+} accelerated to 6.1 MeV/u. In order to take advantage of its lower residual contamination, an EBIS charge breeder will replace the ECR charge breeder in the next two years. The advantages and disadvantages of the two techniques are compared taking into account the requirements of the next generation radioactive beam facilities.

  7. External beam's nozzle design for the CRC cyclotron PIXE/PIGE

    NASA Astrophysics Data System (ADS)

    Choi, Yeon-Gyeong; Kim, Yu-Seok

    2015-02-01

    Recently, 13-MeV proton cyclotrons have been applied to non-destructive trace element analytical techniques, such as proton-induced X-ray emission (PIXE) and proton-induced gamma-ray emission (PIGE). A new extended beam line has been designed for PIXE/PIGE measurements in order to deliver protons to the target with minimal losses, thus reducing secondary radiation. A target chamber for PIXE/PIGE measurements is installed at the end of the extended beam line, and the beam size may be optimized by using a series of collimators that are located in front of the target. The optimized proton beam, with low currents (˜nA) for PIXE/PIGE experiments, requires a small beam size with variable energies from ˜10 keV to 3 MeV. Based on the ionization cross-section curve, a 3-MeV proton beam has been determined to be suitable for PIXE/PIGE measurements. Therefore, the 13-MeV protons extracted from the cyclotron must be reduced to 3 MeV, and this is achieved through the incorporation of an energy degrader. The appropriate thickness of the energy degrader has been estimated by using the stopping range in matter (SRIM) program. Also, suitable materials must be used for the construction of the collimator and the energy degrader in order to meet the requirements of low neutron activation due to the application of protons. In this study, we evaluated a number of suitable materials with low neutron yields and with little energy spread as the beam passes through the energy degrader and collimator. The appropriate thickness of the energy degrader for the reduction of the proton energy from 13 MeV to 3 MeV was determined using the SRIM code. Also, the neutron yield at the nozzle was estimated using the MCNPX code.

  8. The nonlinear theory of slow-wave electron cyclotron masers with inclusion of the beam velocity spread

    SciTech Connect

    Kong, Ling-Bao; Wang, Hong-Yu; Hou, Zhi-Ling; Jin, Hai-Bo; Du, Chao-Hai

    2013-12-15

    The nonlinear theory of slow-wave electron cyclotron masers (ECM) with an initially straight electron beam is developed. The evolution equation of the nonlinear beam electron energy is derived. The numerical studies of the slow-wave ECM efficiency with inclusion of Gaussian beam velocity spread are presented. It is shown that the velocity spread reduces the interaction efficiency. -- Highlights: •The theory of slow-wave electron cyclotron masers is considered. •The calculation of efficiency under the resonance condition is presented. •The efficiency under Gaussian velocity spreads has been obtained.

  9. Simulation of high power broadband cyclotron autoresonance maser amplifier and electron beam experiments

    NASA Astrophysics Data System (ADS)

    Speirs, D. C.; Phelps, A. D. R.; Konoplev, I. V.; Cross, A. W.; He, W.

    2004-04-01

    The design, simulation, and preliminary experimental implementation of an efficient, broadband cyclotron autoresonance maser (CARM) amplifier operating over the 9-13 GHz frequency band is presented. The amplifier is based on a high current accelerator capable of generating a ˜35 A pencil electron beam at an accelerating voltage of ˜450 kV. A full three-dimensional numerical model of the CARM amplifier has been constructed within the particle-in-cell code KARAT taking into account electron beam parameters derived from simulation and experiment. An electron beam current of 32A at an accelerating voltage of 400 kV was measured. Numerical simulations demonstrate the possibility of obtaining 37 dB gain and an interaction efficiency of 17%. In addition a viable amplification bandwidth of 9-13 GHz is apparent, with a minimum gain and efficiency of 25 dB and 10%, respectively, at the boundaries of the amplification band. The peak modeled efficiency and gain (17%, 37 dB) were obtained at a frequency of 12 GHz. Computational simulations have also revealed correlation between the instantaneous amplification bandwidth and the spectral width of cyclotron superradiant emission within the system.

  10. Intense Pulsed Heavy Ion Beam Technology

    NASA Astrophysics Data System (ADS)

    Masugata, Katsumi; Ito, Hiroaki

    Development of intense pulsed heavy ion beam accelerator technology is described for the application of materials processing. Gas puff plasma gun and vacuum arc discharge plasma gun were developed as an active ion source for magnetically insulated pulsed ion diode. Source plasma of nitrogen and aluminum were successfully produced with the gas puff plasma gun and the vacuum arc plasma gun, respectively. The ion diode was successfully operated with gas puff plasma gun at diode voltage 190 kV, diode current 2.2 kA and nitrogen ion beam of ion current density 27 A/cm2 was obtained. The ion composition was evaluated by a Thomson parabola spectrometer and the purity of the nitrogen ion beam was estimated to be 86%. The diode also operated with aluminum ion source of vacuum arc plasma gun. The ion diode was operated at 200 kV, 12 kA, and aluminum ion beam of current density 230 A/cm2 was obtained. The beam consists of aluminum ions (Al(1-3)+) of energy 60-400 keV, and protons (90-130 keV), and the purity was estimated to be 89 %. The development of the bipolar pulse accelerator (BPA) was reported. A double coaxial type bipolar pulse generator was developed as the power supply of the BPA. The generator was tested with dummy load of 7.5 ohm, bipolar pulses of -138 kV, 72 ns (1st pulse) and +130 kV, 70 ns (2nd pulse) were succesively generated. By applying the bipolar pulse to the drift tube of the BPA, nitrogen ion beam of 2 A/cm2 was observed in the cathode, which suggests the bipolar pulse acceleration.

  11. Adaptive Vlasov Simulations of Intense Beams

    SciTech Connect

    Sonnendruecker, Eric; Gutnic, Michael; Haefele, Matthieu; Lemaire, Jean-Louis

    2005-06-08

    Most simulations of intense particle beams are performed nowadays using Particle In Cell (PIC) techniques. Direct grid based Vlasov methods have also been used but mostly for 1D simulations as they become very costly in higher dimensions when using uniform phase space grids. We have recently introduced adaptive mesh refinement techniques that allow us to automatically concentrate the grid points at places where the distribution function is varying most. In this paper we shall introduce this technique and show how it can be used to improve the efficiency of grid based Vlasov solvers.

  12. Cyclotron Autoresonance Accelerator for Electron Beam Dry Scrubbing of Flue Gases

    NASA Astrophysics Data System (ADS)

    Hirshfield, J. L.; Wang, Changbiao

    1997-05-01

    A novel, self-scanning, highly-efficient electron beam source is proposed for electron beam dry scrubbing (EBDS) of flue gases. The beam is prepared using cyclotron autoresonance acceleration (CARA),(C. Wang and J. L. Hirshfield, Phys. Rev. E 51), 2456 (1995); B. Hafizi, P. Sprangle , and J. L. Hirshfield, Phys. Rev. E 50, 3077 (1994). which has already demonstrated an rf efficiency of above 90% experimentally.(M. A. LaPointe, R. B. Yoder, C. Wang, A. K. Ganguly, and J. L. Hirshfield, Phys. Rev. Lett. 76), 2718 (1996). Simulations were done for a 250 kV, 25 A warm beam which is accelerated in a 130 cm CARA using an rf power of 21 MW at 2.856 GHz. The accelerated beam has an energy of up to 1.0 MV, corresponding to 98% acceleration efficiency. The beam can scan across the escaping flue gas with a conical angle of about 11 degrees after a 60-cm down-tapered-to-zero magnetic field. The conical scan angle is adjustable by changing the slope of the tapered magnetic field.

  13. BEST medical radioisotope production cyclotrons

    SciTech Connect

    Sabaiduc, Vasile; Milton, Bruce; Suthanthiran, Krishnan; Johnson, Richard R.; Gelbart, W. Z.

    2013-04-19

    Best Cyclotron Systems Inc (BCSI) is currently developing 14 MeV, 25 MeV, 35MeV and 70MeV cyclotrons for radioisotope production and research applications as well as the entire spectrum of targets and nuclear synthesis modules for the production of Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT) and radiation therapy isotopes. The company is a subsidiary of Best Medical International, renowned in the field of medical instrumentation and radiation therapy. All cyclotrons have external negative hydrogen ion sources, four radial sectors with two dees in opposite valleys, cryogenic vacuum system and simultaneous beam extraction on opposite lines. The beam intensity ranges from 400 {mu}A to 1000 {mu}A, depending on the cyclotron energy and application.

  14. BEST medical radioisotope production cyclotrons

    NASA Astrophysics Data System (ADS)

    Sabaiduc, Vasile; Milton, Bruce; Suthanthiran, Krishnan; Gelbart, W. Z.; Johnson, Richard R.

    2013-04-01

    Best Cyclotron Systems Inc (BCSI) is currently developing 14 MeV, 25 MeV, 35MeV and 70MeV cyclotrons for radioisotope production and research applications as well as the entire spectrum of targets and nuclear synthesis modules for the production of Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT) and radiation therapy isotopes. The company is a subsidiary of Best Medical International, renowned in the field of medical instrumentation and radiation therapy. All cyclotrons have external negative hydrogen ion sources, four radial sectors with two dees in opposite valleys, cryogenic vacuum system and simultaneous beam extraction on opposite lines. The beam intensity ranges from 400 μA to 1000 μA, depending on the cyclotron energy and application [1].

  15. The effect of electron beams on cyclotron maser emission excited by lower-energy cutoffs

    NASA Astrophysics Data System (ADS)

    Zhao, G. Q.; Feng, H. Q.; Wu, D. J.

    2016-05-01

    Electron-cyclotron maser (ECM) is one of the most important emission mechanisms in astrophysics and can be excited efficiently by lower-energy cutoffs of power-law electrons. These non-thermal electrons probably propagate as a directed collimated beam along ambient magnetic fields. This paper investigates the ECM, in which the effect of electron beams is emphasized. Results show the dependence of emission properties of the ECM on the beam feature. The maximum growth rate of the extraordinary mode (X2) rapidly decreases as the beam momentum increases, while the growth rate of the ordinary mode (O1) changes slightly. In particular, the ordinary mode can overcome the extraordinary mode and becomes the fastest growth mode once the beam momentum is large enough. This research presents an extension of the conventional studies on ECM driven by lower-energy cutoffs and may be helpful to understand better the emission process of solar type I radio bursts, which are dominated by the ordinary mode emission.

  16. Intense muon beams and neutrino factories

    SciTech Connect

    Parsa, Z.

    2000-10-05

    High intensity muon sources are needed in exploring neutrino factories, lepton flavor violating muon processes, and lower energy experiments as the stepping phase towards building higher energy {mu}{sup +}{mu}{sup {minus}} colliders. We present a brief overview, sketch of a neutrino source, and an example of a muon storage ring at BNL with detector(s) at Fermilab, Sudan, etc. Physics with low energy neutrino beams based on muon storage rings ({mu}SR) and conventional Horn Facilities are described and compared. CP violation Asymmetries and a new Statistical Figure of Merit to be used for comparison is given. Improvements in the sensitivity of low energy experiments to study Flavor changing neutral currents are also included.

  17. INTENSE NEUTRINO BEAMS AND LEPTONIC CP VIOLATION.

    SciTech Connect

    MARCIANO, W.; PARSA, Z.

    2006-06-13

    Effects of the Leptonic CP violating phase, {delta}, on 3 generation neutrino oscillation rates and asymmetries are discussed. A figure of merit argument is used to show that our ability to measure the phase 6 is rather insensitive to the value of {theta}{sub 13} (for sin{sup 2} 2{theta}{sub 13} {approx}> 0.01) as well as the detector distance (for very long oscillation baselines). Using a study of {nu}{sub {mu}} {yields} {nu}{sub e} oscillations for BNL-Homestake (2540 km) we show that a conventional horn focused wide band neutrino beam generated by an intense 1-2 MW proton source combined with a very large water Cherenkov detector (250-500 kton) should be able to determine {delta} to about {+-}15{sup o} in 5 x 10{sup 7} sec. of running. In addition, such an effort would also measure the other oscillation parameters ({theta}{sub ij}, {Delta}m{sub ij}{sup 2}) with high precision. Similar findings apply to a Fermilab-Homestake (1280 km) baseline. We also briefly discuss features of Superbeams, Neutrino Factories and Beta-Beams.

  18. Materials processing with intense pulsed ion beams

    SciTech Connect

    Rej, D.J.; Davis, H.A.; Olson, J.C.

    1996-12-31

    We review research investigating the application of intense pulsed ion beams (IPIBs) for the surface treatment and coating of materials. The short range (0.1-10 {mu}m) and high-energy density (1-50 J/cm{sup 2}) of these short-pulsed ({le} 1 {mu}s) beams (with ion currents I = 5 - 50 kA, and energies E = 100 - 1000 keV) make them ideal to flash-heat a target surface, similar to the more familiar pulsed laser processes. IPIB surface treatment induces rapid melt and solidification at up to 10{sup 10} K/s to cause amorphous layer formation and the production of non-equilibrium microstructures. At higher energy density the target surface is vaporized, and the ablated vapor is condensed as coatings onto adjacent substrates or as nanophase powders. Progress towards the development of robust, high-repetition rate IPIB accelerators is presented along with economic estimates for the cost of ownership of this technology.

  19. Beam loss studies in high-intensity heavy-ion linacs

    NASA Astrophysics Data System (ADS)

    Ostroumov, P. N.; Aseev, V. N.; Mustapha, B.

    2004-09-01

    The proposed Rare Isotope Accelerator (RIA) Facility, an innovative exotic-beam facility for the production of high-quality beams of short-lived isotopes, consists of a fully superconducting 1.4GV driver linac and a 140MV postaccelerator. To produce sufficient intensities of secondary beams the driver linac will provide 400kW primary beams of any ion from hydrogen to uranium. Because of the high intensity of the primary beams the beam losses must be minimized to avoid radioactivation of the accelerator equipment. To keep the power deposited by the particles lost on the accelerator structures below 1 W/m, the relative beam losses per unit length should be less than 10-5, especially along the high-energy section of the linac. A new beam dynamics simulation code TRACK has been developed and used for beam loss studies in the RIA driver linac. In the TRACK code, ions are tracked through the three-dimensional electromagnetic fields of every element of the linac starting from the electron cyclotron resonance (ECR) ion source to the production target. The simulation starts with a multicomponent dc ion beam extracted from the ECR. The space charge forces are included in the simulations. They are especially important in the front end of the driver linac. Beam losses are studied by tracking a large number of particles (up to 106) through the whole linac considering all sources of error such us element misalignments, rf field errors, and stripper thickness fluctuations. For each configuration of the linac, multiple sets of error values have been randomly generated and used in the calculations. The results are then combined to calculate important beam parameters, estimate beam losses, and characterize the corresponding linac configuration. To track a large number of particles for a comprehensive number of error sets (up to 500), the code TRACK was parallelized and run on the Jazz computer cluster at ANL.

  20. Terahertz electron cyclotron maser interactions with an axis-encircling electron beam

    SciTech Connect

    Li, G. D.; Kao, S. H.; Chang, P. C.; Chu, K. R.

    2015-04-15

    To generate terahertz radiation via the electron cyclotron maser instability, harmonic interactions are essential in order to reduce the required magnetic field to a practical value. Also, high-order mode operation is required to avoid excessive Ohmic losses. The weaker harmonic interaction and mode competition associated with an over-moded structure present challenging problems to overcome. The axis-encircling electron beam is a well-known recipe for both problems. It strengthens the harmonic interaction, as well as minimizing the competing modes. Here, we examine these advantages through a broad data base obtained for a low-power, step-tunable, gyrotron oscillator. Linear results indicate far more higher-harmonic modes can be excited with an axis-encircling electron beam than with an off-axis electron beam. However, multi-mode, time-dependent simulations reveal an intrinsic tendency for a higher-harmonic mode to switch over to a lower-harmonic mode at a high beam current or upon a rapid current rise. Methods are presented to identify the narrow windows in the parameter space for stable harmonic interactions.

  1. Model for the description of ion beam extraction from electron cyclotron resonance ion sources

    SciTech Connect

    Spaedtke, P.

    2010-02-15

    The finite difference method trajectory code KOBRA3-INP has been developed now for 25 years to perform the simulation of ion beam extraction in three dimensions. Meanwhile, the code has been validated for different applications: high current ion beam extraction from plasma sources for ion implantation technology, neutral gas heating in fusion devices, or ion thrusters for space propulsion. One major issue of the development of this code was to improve the flexibility of the applied model for the simulation of different types of particle sources. Fixed emitter sources might be simulated with that code as well as laser ion sources, Penning ion sources, electron cyclotron resonance ion sources (ECRISs), or H{sup -} sources, which require the simulation of negative ions, negative electrons, and positive charges simultaneously. The model which has been developed for ECRIS has now been used to explore the conditions for the ion beam extraction from a still nonexisting ion source, a so called ARC-ECRIS [P. Suominen and F. Wenander, Rev. Sci. Instrum. 79, 02A305 (2008)]. It has to be shown whether the plasma generator has similar properties like regular ECRIS. However, the emittance of the extracted beam seems to be much better compared to an ECRIS equipped with a hexapole.

  2. Electron cyclotron resonance ion source experience at the Heidelberg Ion Beam Therapy Center.

    PubMed

    Winkelmann, T; Cee, R; Haberer, T; Naas, B; Peters, A; Scheloske, S; Spädtke, P; Tinschert, K

    2008-02-01

    Radiotherapy with heavy ions is an upcoming cancer treatment method with to date unparalleled precision. It associates higher control rates particularly for radiation resistant tumor species with reduced adverse effects compared to conventional photon therapy. The accelerator beam lines and structures of the Heidelberg Ion Beam Therapy Center (HIT) have been designed under the leadership of GSI, Darmstadt with contributions of the IAP Frankfurt. Currently, the accelerator is under commissioning, while the injector linac has been completed. When the patient treatment begins in 2008, HIT will be the first medical heavy ion accelerator in Europe. This presentation will provide an overview about the project, with special attention given to the 14.5 GHz electron cyclotron resonance (ECR) ion sources in operation with carbon, hydrogen, helium, and oxygen, and the experience of one year of continuous operation. It also displays examples for beam emittances, measured in the low energy beam transport. In addition to the outlook of further developments at the ECR ion sources for a continuously stable operation, this paper focuses on some of the technical processings of the past year. PMID:18315121

  3. Terahertz electron cyclotron maser interactions with an axis-encircling electron beam

    NASA Astrophysics Data System (ADS)

    Li, G. D.; Kao, S. H.; Chang, P. C.; Chu, K. R.

    2015-04-01

    To generate terahertz radiation via the electron cyclotron maser instability, harmonic interactions are essential in order to reduce the required magnetic field to a practical value. Also, high-order mode operation is required to avoid excessive Ohmic losses. The weaker harmonic interaction and mode competition associated with an over-moded structure present challenging problems to overcome. The axis-encircling electron beam is a well-known recipe for both problems. It strengthens the harmonic interaction, as well as minimizing the competing modes. Here, we examine these advantages through a broad data base obtained for a low-power, step-tunable, gyrotron oscillator. Linear results indicate far more higher-harmonic modes can be excited with an axis-encircling electron beam than with an off-axis electron beam. However, multi-mode, time-dependent simulations reveal an intrinsic tendency for a higher-harmonic mode to switch over to a lower-harmonic mode at a high beam current or upon a rapid current rise. Methods are presented to identify the narrow windows in the parameter space for stable harmonic interactions.

  4. Studies of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN.

    PubMed

    Toivanen, V; Küchler, D

    2016-02-01

    The 14.5 GHz GTS-LHC Electron Cyclotron Resonance Ion Source (ECRIS) provides multiply charged heavy ion beams for the CERN experimental program. The GTS-LHC beam formation has been studied extensively with lead, argon, and xenon beams with varied beam extraction conditions using the ion optical code IBSimu. The simulation model predicts self-consistently the formation of triangular and hollow beam structures which are often associated with ECRIS ion beams, as well as beam loss patterns which match the observed beam induced markings in the extraction region. These studies provide a better understanding of the properties of the extracted beams and a way to diagnose the extraction system performance and limitations, which is otherwise challenging due to the lack of direct diagnostics in this region and the limited availability of the ion source for development work. PMID:26932095

  5. Studies of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN

    NASA Astrophysics Data System (ADS)

    Toivanen, V.; Küchler, D.

    2016-02-01

    The 14.5 GHz GTS-LHC Electron Cyclotron Resonance Ion Source (ECRIS) provides multiply charged heavy ion beams for the CERN experimental program. The GTS-LHC beam formation has been studied extensively with lead, argon, and xenon beams with varied beam extraction conditions using the ion optical code IBSimu. The simulation model predicts self-consistently the formation of triangular and hollow beam structures which are often associated with ECRIS ion beams, as well as beam loss patterns which match the observed beam induced markings in the extraction region. These studies provide a better understanding of the properties of the extracted beams and a way to diagnose the extraction system performance and limitations, which is otherwise challenging due to the lack of direct diagnostics in this region and the limited availability of the ion source for development work.

  6. Parametric coupling of lower hybrid wave with gyrating ion beam driven ion cyclotron instability in a plasma

    SciTech Connect

    Singh, Rohtash; Tripathi, V. K.

    2013-07-15

    A lower hybrid wave, launched into a tokamak for supplementary heating in the presence of neutral beam turned gyrating ion beam, is seen to excite some prominent channels of parametric decay. The beam driven deuterium cyclotron mode is further destabilized by the lower hybrid pump through the nonlinear 4-wave coupling, involving higher and lower frequency lower hybrid sidebands, when ω{sub 0}/k{sub 0z}v{sub 0z}=(1−ω{sub LH}{sup 2}/ω{sub 0}{sup 2}) , where ω{sub LH} is the lower hybrid frequency, ω{sub 0} and k{sub 0z} are the frequency and parallel wave number of the pump wave, and v{sub 0z} is the velocity of ion beam parallel to the magnetic field. The growth rate increases with parallel wave number of the ion-cyclotron mode. The pump is also susceptible to parametric upconversion into an upper sideband shifted by the frequency of the negative energy deuterium cyclotron mode. For typical parameters, the growth rate of this channel is around one fiftieth of deuterium cyclotron frequency and falls off with the transverse wave number of the mode.

  7. Funnel cone for focusing intense ion beams on a target

    SciTech Connect

    Bieniosek, F.M.; Henestroza, E.; Ni, P.

    2009-10-05

    We describe a funnel cone for concentrating an ion beam on a target. The cone utilizes the reflection characteristic of ion beams on solid walls to focus the incident beam andincrease beam intensity on target. The cone has been modeled with the TRIM code. A prototype has been tested and installed for use in the 350-keV K+ NDCX target chamber.

  8. Influence of constant, alternating and cyclotron low-intensity electromagnetic fields on fibroblast proliferative activity in vitro.

    PubMed

    Afinogenov, Gennadi; Afinogenova, Anna; Kalinin, Andrey

    2009-01-01

    Available data allow assuming the presence of stimulation of reparative processes under influence of low-intensity electromagnetic field, commensurable with a magnetic field of the Earth. Research of effects of low-intensity electromagnetic fields on fibroblast proliferative activity in human lungs in cell culture was performed.The influence of a constant electromagnetic field, an alternating electromagnetic field by frequency of 50 Hz and cyclotron electromagnetic field with identical intensity for all kinds of fields - 80 mcTl - on value of cellular mass and a correlation of live and dead cells in culture is investigated in three series of experiments. We used the universal electromagnetic radiator generating all three kinds of fields and supplied by a magnetometer which allows measuring the intensity of accurate within 0.1 mcTl including taking into account the Earth's magnetic field intensity.The peak value for stimulation cellular proliferation in the present experiences was two-hour influence by any of the specified kinds of electromagnetic fields. The irradiation by cyclotron electromagnetic field conducts positive dynamics in growth of live cells (up to 206+/-22%) and decreases the number of dead cells (down to 31+/-6%). Application of cyclotron magnetic fields promoted creation of optimum conditions for proliferation. As a result of researches we observed the reliable 30% increase of nitro-tetrazolium index (in nitro-tetrazolium blue test) after irradiation by cyclotron electromagnetic field in experience that testifies to strengthening of the cell breathing of living cells.In our opinion, it is necessary to pay attention not only to a pure gain of cells, but also to reduction of number dead cells that can be criterion of creation of optimum conditions for their specific development and valuable functioning. PMID:20204088

  9. A new and simple calibration-independent method for measuring the beam energy of a cyclotron.

    PubMed

    Gagnon, Katherine; Jensen, Mikael; Thisgaard, Helge; Publicover, Julia; Lapi, Suzanne; McQuarrie, Steve A; Ruth, Thomas J

    2011-01-01

    This work recommends a new and simple-to-perform method for measuring the beam energy of an accelerator. The proposed method requires the irradiation of two monitor foils interspaced by an energy degrader. The primary advantage of the proposed method, which makes this method unique from previous energy evaluation strategies that employ the use of monitor foils, is that this method is independent of the detector efficiency calibration. This method was evaluated by performing proton activation of (nat)Cu foils using both a cyclotron and a tandem Van de Graaff accelerator. The monitor foil activities were read using a dose calibrator set to an arbitrary calibration setting. Excellent agreement was noted between the nominal and measured proton energies. PMID:20926304

  10. Proton heating and beam formation via parametrically unstable Alfven-cyclotron waves

    NASA Astrophysics Data System (ADS)

    Marsch, Eckart; Araneda, Jaime; -Vinas, Adolfo F.

    Vlasov theory and one-dimensional hybrid simulations are used to study the effects that compressible fluctuations driven by parametric instabilities of Alfvén/cyclotron waves have on proe ton velocity distributions. Field-aligned proton beams are generated during the saturation phase of the wave-particle interaction, with a drift speed which is slightly greater than the Alfvén speed and is maintained until the end of the simulation. The main part of the dise tribution becomes anisotropic due to phase mixing as is typically observed in the velocity distributions measured in the fast solar wind. We identify the key instabilities and also find that even in the parameter regime, where fluid theory appears to be appropriate, strong kinetic effects still prevail.

  11. Transverse beam shape measurements of intense proton beams using optical transition radiation

    SciTech Connect

    Scarpine, Victor E.; /Fermilab

    2012-03-01

    A number of particle physics experiments are being proposed as part of the Department of Energy HEP Intensity Frontier. Many of these experiments will utilize megawatt level proton beams onto targets to form secondary beams of muons, kaons and neutrinos. These experiments require transverse size measurements of the incident proton beam onto target for each beam spill. Because of the high power levels, most beam intercepting profiling techniques will not work at full beam intensity. The possibility of utilizing optical transition radiation (OTR) for high intensity proton beam profiling is discussed. In addition, previous measurements of OTR beam profiles from the NuMI beamline are presented.

  12. Intense beams: The past, present, and future

    SciTech Connect

    Yonas, G.; Sweeney, M.A.

    1998-06-01

    Nobody could have predicted the circuitous course of the last 30 years of progress in intense beams and pulsed power. There were many discoveries and twists and turns along the way, but the steady flow of understanding and technological advances has sustained the field. Pulsed power research began in the early 1960s with the development of the technology to test the reliability of nuclear weapons in a pulsed radiation environment. Because of the effort in the 1970s on an electron beam approach to inertial confinement fusion (ICF) at Sandia National Laboratories and at the Kurchatov Institute, simulation codes, diagnostics, and innovative pulsed power techniques such as self-magnetic insulation were developed. The electron approach ended in 1979, and the more promising ion approach continued. At the same time, z pinches, used since the early 1970s to evaluate the response of materials to keV X rays, were considered as an alternative to drive ICF capsules. The use of z pinches for ICF was discontinued in 1984 because of budget cuts and the belief that ions offered a route to the standoff requirement for energy applications. Now, in 1998, because of budget limitations and the 1995 discovery that the soft x-ray power achievable in a z-pinch implosion can be greatly enhanced, the ion approach has been suspended, and a new facility, X-1, proposed to achieve high yield in the laboratory with z pinches. In this paper the authors review the research paths that led to these changes, describe the present status of z pinches, and predict what the future holds. Although nobody can predict the future, the past 30 years have taught us some lessons that can be applied to the next 30 years. The paper concludes with some of these lessons learned.

  13. Electron cyclotron resonance 140 mA D(+) beam extraction optimization for IFMIF EVEDA accelerator.

    PubMed

    Delferrière, O; De Menezes, D; Gobin, R; Harrault, F; Tuske, O

    2008-02-01

    Based on the experience of the SILHI electron cyclotron resonance (ECR) ion source for the IPHI accelerator, which produces routinely 100-120 mA H(+) beam, the CEA-Saclay is in charge of the design and realization of the 140 mA cw deuteron source for the IFMIF project (International Fusion Materials Irradiation Facility). IFMIF is an accelerator-based neutron irradiation facility consisting of two accelerators of 125 mA D(+) beam at 40 MeV that hit in parallel a lithium target. IFMIF utilizes the deuteron-lithium (d-Li) neutron, producing a reaction to simulate the 14 MeV neutron environment in deuterium-tritium (D-T) fusion reactors. In the framework of the IFMIF EVEDA phase (Engineering Validation and Engineering Design Activities), we are studying a cw ECR ion source with a new extraction system to allow high current extraction while keeping a low divergence as well as a small emittance. Starting from SILHI five-electrode system with H(+) ions, the extracted beam characteristics as well as electric field conditions are compared with the cases of four- and three-electrode extraction systems. Experimental results made on the SILHI source with H(+) ions are briefly discussed. Extensive experimental results on the new source test bench BETSI are expected as soon as the design and fabrication of a dedicated extraction system with a new set of electrodes will be finished. PMID:18315214

  14. Design of large vacuum chamber for VEC superconducting cyclotron beam line switching magnet

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Sumantra; Nandi, Chinmoy; Gayen, Subhasis; Roy, Suvadeep; Mishra, Santosh Kumar; Ramrao Bajirao, Sanjay; Pal, Gautam; Mallik, C.

    2012-11-01

    VEC K500 superconducting cyclotron will be used to accelerate heavy ion. The accelerated beam will be transported to different beam halls by using large switching magnets. The vacuum chamber for the switching magnet is around 1000 mm long. It has a height of 85 mm and width varying from 100 mm to 360 mm. The material for the chamber has been chosen as SS304.The material for the vacuum chamber for the switching magnet has been chosen as SS304. Design of the vessel was done as per ASME Boiler and Pressure Vessel Code, Section VIII, Division 1. It was observed that primary stress values exceed the allowable limit. Since, the magnet was already designed with a fixed pole gap; increase of the vacuum chamber plate thickness restricts the space for beam transport. Design was optimized using stress analysis software ANSYS. Analysis was started using plate thickness of 4 mm. The stress was found higher than the allowable level. The analysis was repeated by increasing plate thickness to 6 mm, resulting in the reduction of stress level below the allowable level. In order to reduce the stress concentration due to sharp bend, chamfering was done at the corner, where the stress level was higher. The thickness of the plate at the corner was increased from 6 mm to 10 mm. These measures resulted in reduction of localized stress.

  15. Fast neutral beam ion source coupled to a Fourier transform ion cyclotron resonance mass spectrometer

    SciTech Connect

    Hill, N.C.; Limbach, P.A.; Shomo, R.E. II; Marshall, A.G. ); Appelhans, A.D.; Delmore, J.E. )

    1991-11-01

    The coupling of an autoneutralizing SF{sup {minus}}{sub 6} fast ion-beam gun to a Fourier transform ion cyclotron resonance (FT/ICR) mass spectrometer is described. The fast neutral beam provides for secondary-ion-type FT/ICR mass analysis (e.g., production of abundant pseudomolecular (M+H){sup +} ions) of involatile samples without the need for external ion injection, since ions are formed at the entrance to the ICR ion trap. The design, construction, and testing of the hybrid instrument are described. The feasibility of the experiment (for both broadband and high-resolution FT/ICR positive-ion mass spectra) is demonstrated with {ital tetra}-butylammonium bromide and a Tylenol{sup ( )} sample. The ability to analyze high molecular weight polymers with high mass resolution is demonstrated for Teflon{sup ( )}. All of the advantages of the fast neutral beam ion source previously demonstrated with quadrupole mass analysis are preserved, and the additional advantages of FT/ICR mass analysis (e.g., high mass resolving power, ion trapping) are retained.

  16. Fast neutral beam ion source coupled to a Fourier transform ion cyclotron resonance mass spectrometer

    NASA Astrophysics Data System (ADS)

    Hill, Nicholas C.; Limbach, Patrick A.; Shomo, Ronald E., II; Marshall, Alan G.; Appelhans, Anthony D.; Delmore, James E.

    1991-11-01

    The coupling of an autoneutralizing SF-6 fast ion-beam gun to a Fourier transform ion cyclotron resonance (FT/ICR) mass spectrometer is described. The fast neutral beam provides for secondary-ion-type FT/ICR mass analysis [e.g., production of abundant pseudomolecular (M+H)+ ions] of involatile samples without the need for external ion injection, since ions are formed at the entrance to the ICR ion trap. The design, construction, and testing of the hybrid instrument are described. The feasibility of the experiment (for both broadband and high-resolution FT/ICR positive-ion mass spectra) is demonstrated with tetra-butylammonium bromide and a Tylenol■ sample. The ability to analyze high molecular weight polymers with high mass resolution is demonstrated for Teflon■. All of the advantages of the fast neutral beam ion source previously demonstrated with quadrupole mass analysis are preserved, and the additional advantages of FT/ICR mass analysis (e.g., high mass resolving power, ion trapping) are retained.

  17. Longitudinal Density Modulation and Energy Conversion in Intense Beams

    SciTech Connect

    Harris, J; Neumann, J; Tian, K; O'Shea, P

    2006-02-17

    Density modulation of charged particle beams may occur as a consequence of deliberate action, or may occur inadvertently because of imperfections in the particle source or acceleration method. In the case of intense beams, where space charge and external focusing govern the beam dynamics, density modulation may under some circumstances be converted to velocity modulation, with a corresponding conversion of potential energy to kinetic energy. Whether this will occur depends on the properties of the beam and the initial modulation. This paper describes the evolution of discrete and continuous density modulations on intense beams, and discusses three recent experiments related to the dynamics of density-modulated electron beams.

  18. A measurement of the fast-neutron sensitivity of a Geiger - Müller detector in the pulsed neutron beam from a superconducting cyclotron

    NASA Astrophysics Data System (ADS)

    Maughan, R. L.; Yudelev, M.; Kota, C.

    1996-08-01

    The value of a commercially available miniature energy compensated Geiger - Müller (GM) detector has been determined using the modified lead attenuation method of Hough. The measurements were made in a d(48.5) - Be neutron beam produced by the superconducting cyclotron based neutron therapy facility at Harper Hospital. The unique problems associated with making measurements in a 2 ms duration pulsed beam with a 20% duty cycle are discussed. The beam monitoring system, which allows the beam pulse shape at low beam intensities to be measured, is described. By gating the GM output with a discriminator pulse derived from the beam pulse shape, the gamma-ray count rates and dead-time corrections within the 2 ms pulse and between pulses can be measured separately. The value of determined for this GM detector is consistent with the values measured by other workers with identical and similar detectors in neutron beams with comparable, but not identical, neutron spectra.

  19. SU-E-T-388: Estimating the Radioactivity Inventory of a Cyclotron Based Pencil Beam Proton Therapy Facility

    SciTech Connect

    Langen, K; Chen, S

    2014-06-01

    Purpose: Parts of the cyclotron and energy degrader are incidentally activated by protons lost during the acceleration and transport of protons for radiation therapy. An understanding of the radioactive material inventory is needed when regulatory requirements are assessed. Methods: First, the tumor dose and volume is used to determine the required energy deposition. For spot scanning, the tumor length along the beam path determines the number of required energy layers. For each energy layer the energy deposition per proton can be calculated from the residual proton range within the tumor. Assuming a typical layer weighting, an effective energy deposition per proton can then be calculated. The total number of required protons and the number of protons per energy layer can then be calculated. For each energy layer, proton losses in the energy degrader are calculated separately since its transmission efficiency, and hence the amount of protons lost, is energy dependent. The degrader efficiency also determines the number of protons requested from the cyclotron. The cyclotron extraction efficiency allows a calculation of the proton losses within the cyclotron. The saturation activity induced in the cyclotron and the degrader is equal to the production rate R for isotopes whose half-life is shorter that the projected cyclotron life time. R can be calculated from the proton loss rate and published production cross sections. Results: About 1/3 of the saturation activity is produced in the cyclotron and 2/3 in the energy degrader. For a projected case mix and a patient load of 1100 fractions per week at 1.8 Gy per fraction a combined activity of 180 mCi was estimated at saturation. Conclusion: Calculations were used to support to application of a radioactive materials license for the possession of 200 mCi of activity for isotopes with atomic numbers ranging from 1-83.

  20. Comparison of short-lived medical isotopes activation by laser thin target induced protons and conventional cyclotron proton beams

    NASA Astrophysics Data System (ADS)

    Murray, Joseph; Dudnikova, Galina; Liu, Tung-Chang; Papadopoulos, Dennis; Sagdeev, Roald; Su, J. J.; UMD MicroPET Team

    2014-10-01

    Production diagnostic or therapeutic nuclear medicines are either by nuclear reactors or by ion accelerators. In general, diagnostic nuclear radioisotopes have a very short half-life varying from tens of minutes for PET tracers and few hours for SPECT tracers. Thus supplies of PET and SPECT radiotracers are limited by regional production facilities. For example 18F-fluorodeoxyglucose (FDG) is the most desired tracer for positron emission tomography because its 110 minutes half-life is sufficient long for transport from production facilities to nearby users. From nuclear activation to completing image taking must be done within 4 hours. Decentralized production of diagnostic radioisotopes will be idea to make high specific activity radiotracers available to researches and clinicians. 11 C, 13 N, 15 O and 18 F can be produced in the energy range from 10-20 MeV by protons. Protons of energies up to tens of MeV generated by intense laser interacting with hydrogen containing targets have been demonstrated by many groups in the past decade. We use 2D PIC code for proton acceleration, Geant4 Monte Carlo code for nuclei activation to compare the yields and specific activities of short-lived isotopes produced by cyclotron proton beams and laser driven protons.

  1. Formation of multi-charged ion beams by focusing effect of mid-electrode on electron cyclotron resonance ion source

    SciTech Connect

    Imai, Youta Kimura, Daiju; Kurisu, Yosuke; Nozaki, Dai; Yano, Keisuke; Kumakura, Sho; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

    2014-02-15

    We are constructing a tandem type electron cyclotron resonance ion source (ECRIS) and a beam line for extracting ion beams. The ion beam is extracted from the second stage by an accel-decel extraction system with a single-hole and the ion beam current on each electrode is measured. The total ion beam current is measured by a faraday cup downstream the extraction electrodes. We measure these currents as a function of the mid-electrode potential. We also change the gap length between electrodes and perform similar measurement. The behaviors of these currents obtained experimentally against the mid-electrode potential show qualitatively good agreement with a simple theoretical consideration including sheath potential effects. The effect of mid-electrode potential is very useful for decreasing the beam loss for enhancing ion beam current extracted from ECRIS.

  2. Fermilab main injector: High intensity operation and beam loss control

    NASA Astrophysics Data System (ADS)

    Brown, Bruce C.; Adamson, Philip; Capista, David; Chou, Weiren; Kourbanis, Ioanis; Morris, Denton K.; Seiya, Kiyomi; Wu, Guan Hong; Yang, Ming-Jen

    2013-07-01

    From 2005 through 2012, the Fermilab Main Injector provided intense beams of 120 GeV protons to produce neutrino beams and antiprotons. Hardware improvements in conjunction with improved diagnostics allowed the system to reach sustained operation at 400 kW beam power. Transmission was very high except for beam lost at or near the 8 GeV injection energy where 95% beam transmission results in about 1.5 kW of beam loss. By minimizing and localizing loss, residual radiation levels fell while beam power was doubled. Lost beam was directed to either the collimation system or to the beam abort. Critical apertures were increased while improved instrumentation allowed optimal use of available apertures. We will summarize the improvements required to achieve high intensity, the impact of various loss control tools and the status and trends in residual radiation in the Main Injector.

  3. Electron-beam-assisted dry etching for GaAs using electron cyclotron resonance plasma electron source

    NASA Astrophysics Data System (ADS)

    Watanabe, Heiji; Matsui, Shinji

    1992-12-01

    Electron-beam (EB)-assisted dry etching of GaAs using Ar electron cyclotron resonance (ECR) plasma as an electron shower source is developed to achieve a low energy and high current density electron beam (EB). The rate of EB-assisted dry etching is more than ten times larger than for Cl2 gas etching.It is confirmed, through photoluminescence measurement, that this etching method causes less damage than ion beam techniques and is very effective for damaged layer removal. Using this technique, a 0.4 μm linewidth low-damage fine structure of GaAs was fabricated.

  4. Doubling Main Injector beam intensity using RF barrier

    SciTech Connect

    King-Yuen Ng

    2002-09-30

    Using rf barriers, 12 booster batches can be injected into the Fermilab Main Injector continuously, thus doubling the usual beam intensity. After that, adiabatic capture of the beam into 53 MHz buckets can be accomplished in about 10 ms. The beam loading voltages in the rf cavities are small and they can be eliminated by a combination of counterphasing and mechanical shorts.

  5. Beam diagnostics at high-intensity storage rings

    SciTech Connect

    Plum, M.

    1993-11-01

    Beam diagnostics at high-intensity facilities feature their own special set of problems and characteristics. Issues peculiar to high-intensity storage rings include beam loss, beam halos, extraction efficiency, beam in the gap, clearing electrodes, and beam-profile measurement. The Los Alamos Proton Storage Ring (PSR) is a nice example of a high-intensity storage ring. The author discusses in some detail three diagnostic systems currently in use at the PSR: the beam-loss-monitor system, the electron-clearing system, and the beam-in-the-gap monitor. Much of the discussion is inspired by the problems that were encountered and the useful things learned while commissioning and developing the PSR. Another inspiration is the work on the next-generation neutron-spallation source, also known as the National Center for Neutron Research (NCNR).

  6. Beam diagnostics at high-intensity storage rings

    SciTech Connect

    Plum, M. )

    1994-10-10

    Beam diagnostics at high-intensity facilities feature their own special set of problems and characteristics, issues peculiar to high-intensity storage rings include beam loss, beam halos, extraction efficiency, beam in the gap, clearing electrodes, and beam-profile measurement. The Los Alamos Proton Storage Ring (PSR) is a nice example of a high-intensity storage ring. I will discuss in some detail three diagnostic systems currently in use at the PSR: the beam-loss-monitor system, the electron-clearing system, and the beam-in-the-gap monitor. Much of our discussion is inspired by the problems we have encountered and the useful things we have learned while commissioning and developing the PSR. Another inspiration is our work on the next-generation neutron-spallation source, also known as the National Center for Neutron Research (NCNR).

  7. Intensity dependence of relativistic focusing of intense laser beams propagating in plasmas

    SciTech Connect

    Liu Mingwei; Zhou Bingju; Yi Yougen; Liu Xiaojuan; Tang Liqiang

    2007-10-15

    Optical guiding of an intense laser beam propagating in uniform plasmas is analyzed by means of the variational method. The focusing properties of the beam are shown to be governed by the laser power as well as the laser intensity. An increase in the laser intensity leads to an enhancement of ponderomotive self-channeling but a stronger weakening of relativistic self-focusing. The oscillations of the beam spot size along the propagation distance come from the variability of the focusing force in terms of the laser intensity; and the dependence on the laser intensity is negligible in the weakly relativistic limit.

  8. Intense beams from gases generated by a permanent magnet ECR ion source at PKUa)

    NASA Astrophysics Data System (ADS)

    Ren, H. T.; Peng, S. X.; Lu, P. N.; Yan, S.; Zhou, Q. F.; Zhao, J.; Yuan, Z. X.; Guo, Z. Y.; Chen, J. E.

    2012-02-01

    An electron cyclotron resonance (ECR) ion source is designed for the production of high-current ion beams of various gaseous elements. At the Peking University (PKU), the primary study is focused on developing suitable permanent magnet ECR ion sources (PMECRs) for separated function radio frequency quadrupole (SFRFQ) accelerator and for Peking University Neutron Imaging Facility. Recently, other kinds of high-intensity ion beams are required for new acceleration structure demonstration, simulation of fusion reactor material irradiation, aviation bearing modification, and other applications. So we expanded the ion beam category from O+, H+, and D+ to N+, Ar+, and He+. Up to now, about 120 mA of H+, 83 mA of D+, 50 mA of O+, 63 mA of N+, 70 mA of Ar+, and 65 mA of He+ extracted at 50 kV through a ϕ 6 mm aperture were produced by the PMECRs at PKU. Their rms emittances are less than 0.2 π mm mrad. Tungsten samples were irradiated by H+ or He+ beam extracted from this ion source and H/He holes and bubbles have been observed on the samples. A method to produce a high intensity H/He mixed beam to study synergistic effect is developed for nuclear material irradiation. To design a He+ beam injector for coupled radio frequency quadruple and SFRFQ cavity, He+ beam transmission experiments were carried out on PKU low energy beam transport test bench and the transmission was less than 50%. It indicated that some electrode modifications must be done to decrease the divergence of He+ beam.

  9. Intense beams from gases generated by a permanent magnet ECR ion source at PKU.

    PubMed

    Ren, H T; Peng, S X; Lu, P N; Yan, S; Zhou, Q F; Zhao, J; Yuan, Z X; Guo, Z Y; Chen, J E

    2012-02-01

    An electron cyclotron resonance (ECR) ion source is designed for the production of high-current ion beams of various gaseous elements. At the Peking University (PKU), the primary study is focused on developing suitable permanent magnet ECR ion sources (PMECRs) for separated function radio frequency quadrupole (SFRFQ) accelerator and for Peking University Neutron Imaging Facility. Recently, other kinds of high-intensity ion beams are required for new acceleration structure demonstration, simulation of fusion reactor material irradiation, aviation bearing modification, and other applications. So we expanded the ion beam category from O(+), H(+), and D(+) to N(+), Ar(+), and He(+). Up to now, about 120 mA of H(+), 83 mA of D(+), 50 mA of O(+), 63 mA of N(+), 70 mA of Ar(+), and 65 mA of He(+) extracted at 50 kV through a φ 6 mm aperture were produced by the PMECRs at PKU. Their rms emittances are less than 0.2 π mm mrad. Tungsten samples were irradiated by H(+) or He(+) beam extracted from this ion source and H∕He holes and bubbles have been observed on the samples. A method to produce a high intensity H∕He mixed beam to study synergistic effect is developed for nuclear material irradiation. To design a He(+) beam injector for coupled radio frequency quadruple and SFRFQ cavity, He(+) beam transmission experiments were carried out on PKU low energy beam transport test bench and the transmission was less than 50%. It indicated that some electrode modifications must be done to decrease the divergence of He(+) beam. PMID:22380337

  10. Development status of an intense beam klystron

    SciTech Connect

    Coleman, P.D.; Lemke, R.W.; Hendricks, K.J.; Arman, M.J.; Bowers, L.A.

    1994-10-01

    Investigations are being performed on a high current (16 kA), mildly relativistic (400kV), L-band klystron source. Experiments are in an early stage, and thus far have progressed to beam modulation studies. This paper discusses general klystron design considerations, beam propagation results, initial modulation results, and various extraction techniques being considered.

  11. Intense non-relativistic cesium ion beam

    SciTech Connect

    Lampel, M.C.

    1984-02-01

    The Heavy Ion Fusion group at Lawrence Berkeley Laboratory has constructed the One Ampere Cesium Injector as a proof of principle source to supply an induction linac with a high charge density and high brightness ion beam. This is studied here. An electron beam probe was developed as the major diagnostic tool for characterizing ion beam space charge. Electron beam probe data inversion is accomplished with the EBEAM code and a parametrically adjusted model radial charge distribution. The longitudinal charge distribution was not derived, although it is possible to do so. The radial charge distribution that is derived reveals an unexpected halo of trapped electrons surrounding the ion beam. A charge fluid theory of the effect of finite electron temperature on the focusing of neutralized ion beams (Nucl. Fus. 21, 529 (1981)) is applied to the problem of the Cesium beam final focus at the end of the injector. It is shown that the theory's predictions and assumptions are consistent with the experimental data, and that it accounts for the observed ion beam radius of approx. 5 cm, and the electron halo, including the determination of an electron Debye length of approx. 10 cm.

  12. Final focus system for high intensity beams

    SciTech Connect

    Henestroza, E.; Bieniosek, F.M.; Eylon, S.; Roy, P.K.; Yu, S.S.

    2003-05-01

    The NTX experiment at the Heavy Ion Fusion Virtual National Laboratory is exploring the performance of neutralized final focus systems for high perveance heavy ion beams. The NTX final focus system produces a converging beam at the entrance to the neutralized drift section where it focuses to a small spot. The final focus lattice consists of four pulsed quadrupole magnets. The main issues are the control of emittance growth due to high order fields from magnetic multipoles and image fields. We will present experimental results from NTX on beam envelope and phase space distributions, and compare these results with particle simulations using the particle-in-cell code WARP.

  13. Cyclotrons: From Science to Human Health

    NASA Astrophysics Data System (ADS)

    Craddock, Michael

    2011-04-01

    Lawrence's invention of the cyclotron, whose 80th anniversary we have just celebrated, not only revolutionized nuclear physics, but proved the starting point for a whole variety of recirculating accelerators, from the smallest microtron to the largest synchrotron, that have had an enormous impact in almost every branch of science and in several areas of medicine and industry. Cyclotrons themselves have proved remarkably adaptable, incorporating a variety of new ideas and technologies over the years: frequency modulation, edge focusing, AG focusing, separate magnet sectors, axial and azimuthal injection, ring geometries, stripping extraction, superconducting magnets and rf...... Even FFAGs, those most complex members of the cyclotron (fixed-magnetic-field) family, are making a comeback. Currently there are more than 50 medium or large cyclotrons around the world devoted to research. These provide intense primary beams of protons or stable ions, and correspondingly intense secondary beams of neutrons, pions, muons and radioactive ions, for experiments in nuclear, particle and condensed-matter physics, and in the materials and life sciences. Far outnumbering these, however, are the 800 or so small and medium cyclotrons used to produce radioisotopes for medical and other purposes. In addition, a rapidly growing number of 230-MeV proton cyclotrons are being built for cancer therapy -12 brought into operation since 1998 and as many more in the works. Altogether, cyclotrons are flourishing!

  14. Space charge instabilities in gyrotron beams and theory of gyro-traveling-wave-amplifiers at cyclotron harmonics

    SciTech Connect

    Li, H.

    1993-01-01

    This dissertation concerns itself with two important issues in the study of gyrotrons. In Part I, the authors study the space charge instabilities in gyrotron electron beams via both solution of the linear dispersion equation and the nonlinear particle simulation. The linear analysis addressed the stabilizing effects of energy spread in the beams and the gradient of the external magnetic field. The nonlinear multi-frequency simulation demonstrates that the energy spread induced by multiple unstable waves in the nonlinear saturation stage is more significant than the corresponding spread induced by a single unstable wave. This indicates that the deleterious effect on the quality of the beam will be greater than previously expected, and emphasizes the need to design electron guns which are stable to this wave mode. In Part II, the authors develop a generalized theory of gyro-traveling-wave tubes (gyro-TWTs) operating at arbitrary cyclotron harmonics. In the framework of small signal theory, the authors obtain and analyze the dispersion equation and discuss a problem of spurious counterpropagating waves excitation. In the large-signal study, the authors predict the possibility of achieving high efficiency of operation at the first four cyclotron harmonics and show that the orbital efficiency of the relativistic gyro-TWT operating at the second cyclotron harmonic with large frequency up-conversion may exceed 60%. The results obtained also demonstrate that the sensitivity of the harmonic gyro-TWT efficiency with respect to the electron velocity spread strongly depends on axial wavenumbers of the travelling waves.

  15. Collective Focusing of a Plasma-Neutralized Intense Ion Beam Propagating Along a Weak Solenoidal Magnetic Field

    NASA Astrophysics Data System (ADS)

    Dorf, Mikhail A.; Kaganovich, Igor D.; Startsev, Edward A.; Davidson, Ronald C.

    2009-11-01

    Two schemes are considered for focusing intense ion beams utilizing the collective dynamics of plasma electrons. In the first approach, an ion beam propagates through a neutralizing background plasma along a uniform magnetic field. In the second approach, an ion beam passes through a finite size plasma, extracts neutralizing electrons from the plasma, and then enters a magnetic lens. In the both cases, a strong radial electric field is produced due to the collective electron dynamics. This self-electric field provides the enhanced transverse focusing of the ion beam. Detailed analytical and advanced numerical studies using particle-in-cell simulations are performed for both approaches. The radial focusing force acting on beam ions is calculated for an arbitrary ratio between the electron cyclotron and plasma frequencies. Collective focusing effects are shown to be important for the design of heavy ion drivers for high energy density and warm dense matter physics applications.

  16. Intense microwave and particle beams; Proceedings of the Meeting, Los Angeles, CA, Jan. 16-19, 1990

    SciTech Connect

    Brandt, H.E.

    1990-01-01

    Various papers on intense microwave and particle beams are presented. Individual topics addressed include: influence of beam loading on the operation of the relativistic klystron amplifier, gain and efficiency studies of a high-power traveling-wave-tube amplifier, relativistic O-type oscillator-amplifier systems, stability of mutually coupled oscillators, effects of a dense background plasma on the dispersion of backward wave oscillators, scalarized photon analysis of spontaneous emission in the uniform magnetic field FEL, tunable 200-GHz electron cyclotron maser, plasma-filled dielectric Cerenkov maser, MIT 35-GHz cyclotron autoresonance maser amplifier, array feed/reflector antenna design for intense microwave beams, propagation of an intense microwave beam from a phased array. Also discussed are: electromagnetic missile from a nonuniform aperture field, backscattering of electromagnetic missiles, plasma waveguide, electromagnetic missiles from currents on fractal sets, effects of high-power RF fields in the atmosphere and the ionosphere, pulsed sources and currents for acoustic and electromagnetic bullets, digital transmitter array for producing enhanced ionization.

  17. The development of the high intensity electron cyclotron resonance ion source at China Institute of Atomic Energy.

    PubMed

    Tang, B; Ma, R; Ma, Y; Chen, L; Huang, Q; Liang, H; Cui, B; Jiang, W

    2014-02-01

    High-current microwave ion source has been under development over 15 years for accelerator driven sub-critical system research at China Institute of Atomic Energy, and the beam intensity higher than 140 mA proton beam is produced by this ion source with long lifetime and high reliability. The emittance of high intensity continue-wave and pulse beam is measured on a test-bench in the laboratory. Based on the good performance of this proton ion source, a new 120 mA deuterium ion source is proposed for a high intensity neutron generator. The ion source details and status will be presented. PMID:24593490

  18. Final report to US Department of Energy: Cyclotron autoresonance accelerator for electron beam dry scrubbing of flue gases

    SciTech Connect

    Hirshfield, J.L.

    2001-05-25

    Several designs have been built and operated of microwave cyclotron autoresonance accelerators (CARA's) with electron beam parameters suitable for remediation of pollutants in flue gas emissions from coal-burning power plants. CARA designs have also been developed with a TW-level 10.6 micron laser driver for electron acceleration from 50 to 100 MeV, and with UHF drivers for proton acceleration to over 500 MeV. Dose requirements for reducing SO2, NOx, and particulates in flue gas emissions to acceptable levels have been surveyed, and used to optimize the design of an electron beam source to deliver this dose.

  19. Neutralized transport of high intensity beams

    SciTech Connect

    Henestroza, E.; Yu, S.S.; Eylon, S.; Roy, P.K.; Anders, A.; Sharp, W.; Efthimion, P.; Gilson, E.; Welch, D.; Rose, D.

    2003-05-01

    The NTX experiment at the Heavy Ion Fusion Virtual National Laboratory is exploring the performance of neutralized final focus systems for high perveance heavy ion beams. A converging ion beam at the exit of the final focus magnetic system is injected into a neutralized drift section. The neutralization is provided by a metal arc source and an RF plasma source. Effects of a ''plasma plug'', where electrons are extracted from a localized plasma in the upstream end of the drift section, and are then dragged along by the ion potential, as well as the ''volumetric plasma'', where neutralization is provided by the plasma laid down along the ion path, are both studied and their relative effects on the beam spot size are compared. Comparisons with 3-D PIC code predictions will also be presented.

  20. RCNP cyclotron facility and application program

    NASA Astrophysics Data System (ADS)

    Hatanaka, Kichiji

    2013-05-01

    The RCNP cyclotron cascade system consists of K140 AVF cyclotron and K400 ring cyclotron and is providing high quality beams for various experiments. Three kinds of neutron sources are developed for applications as well as fundamental physics. They provide monoenergetic neutrons at 10-400 MeV, white neutrons with the same energy spectra as terrestrial neutrons on the earth, and ultra cold neutrons with energies below 210 neV. There are increasing demands for high intensity beams and even to improve the quality. In order to increase the physics research opportunities, a new injector cyclotron is proposed, which has four separated sector magnets and two accelerating cavities. Sector magnets are designed to use High Temperature Superconducting (HTS) wire. At RCNP, we have been developing magnets with HTS wires for a decade.

  1. Gridded Electron Guns and Modulation of Intense Beams

    SciTech Connect

    Harris, J R; O'Shea, P G

    2006-05-02

    Gridded guns are useful for producing modulated electron beams. This modulation is generally limited to simple gating of the beam, but may be used to apply structure to the beam pulse shape. In intense beams, this structure spawns space charge waves whose dynamics depend in part on the relative strengths of the velocity and density variations which comprise the initial current modulation. In this paper, we calculate the strengths of beam current and velocity modulation produced in a gridded electron gun, and show that under normal conditions the initial modulation is dominated by density variation rather than velocity variation.

  2. Anisotropy-driven collective instability in intense charged particle beams

    NASA Astrophysics Data System (ADS)

    Startsev, Edward A.; Davidson, Ronald C.; Qin, Hong

    2005-12-01

    The classical electrostatic Harris instability is generalized to the case of a one-component intense charged particle beam with anisotropic temperature including the important effects of finite transverse geometry and beam space charge. For a long, coasting beam, the eigenmode code bEASt have been used to determine detailed 3D stability properties over a wide range of temperature anisotropy and beam intensity. A simple theoretical model is developed which describes the essential features of the linear stage of the instability. Both the simulations and the analytical theory clearly show that moderately intense beams are linearly unstable to short-wavelength perturbations provided the ratio of the longitudinal temperature to the transverse temperature is smaller than some threshold value. The delta-f particle-in-cell code BEST has been used to study the detailed nonlinear evolution and saturation of the instability.

  3. Formation of a conical distribution and intense ion heating in the presence of hydrogen cyclotron waves

    NASA Astrophysics Data System (ADS)

    Okuda, H.; Ashour-Abdalla, M.

    1981-07-01

    In the considered investigation, it is assumed that the field aligned currents are responsible for producing electrostatic harmonic cyclotron waves (EHC). Using a one-dimensional simulation model in which the electron velocity distribution is maintained by a constant injection of the initial distribution, it is shown that, in contrast to earlier initial value simulations, EHC waves grow to a large amplitude, resulting in the formation of an anisotropic ion velocity distribution. Both the heating rate and the anisotropy are in reasonable agreement with the quasi-linear theory, taking into account the cyclotron resonance. The results show that the saturation is due to the combined effects of wave induced diffusion in an electron velocity space and the heating of ions perpendicularly. Both these effects reduce the growth rate.

  4. Intense electron beam propagation across a magnetic field

    SciTech Connect

    Zhang, X.; Striffler, C.D.; Yao, R.L.; Destler, W.W.; Reiser, M.P.

    1989-01-01

    In this paper we consider the propagation of an intense electron-ion beam across an applied magnetic field. In the absence of the applied field, the beam system is in a Bennett equilibrium state that involves electrons with both large axial and thermal velocities and a cold stationary space-charge neutralizing ion species. Typical parameters under consideration are V{sub o} {approximately} 1 MV, I {approximately} 5 kA, T{sub e} {approximately} 100 keV, and beam radii {approximately} 1 cm. We find that in the intense beam regime, the propagation is limited due to space-charge depression caused by the deflection of the electron beam by the transverse field. This critical field is of the order of the peak self-magnetic field of the electron beam which is substantially higher than the single particle cut-off field. 8 refs., 3 figs.

  5. Beam Charge Asymmetry Monitors for Low Intensity Continuous Electron Beam

    SciTech Connect

    Jean-Claude Denard; Arne P. Freyberger; Youri Sharabian

    2001-05-01

    Experimental Hall B at Jefferson Lab typically operates with CW electron beam currents in the range of 1 - 10 nA. This low beam current coupled with a 30 Hz flip rate of the beam helicity required the development of new devices to measure and monitor the beam charge asymmetry. We have developed four independent devices with sufficient bandwidth for readout at 30 Hz rate: a synchrotron light monitor (SLM), two backward optical transition radiation monitors (OTR) and a Faraday Cup. Photomultipliers operating in current mode provided the readout of the light from the SLM and the OTRs, while high bandwidth electronics provided the readout from the Faraday cup. Using {approximately}6 helicity pairs, we measured the beam charge asymmetry to a statistically accuracy which is better than 0.05%. We present the results from the successful operation of these devices during the fall 2000 physics program. The reliability and the bandwidth of the devices allowed us to control the gain on the source laser by means of a feedback loop.

  6. Improving Plating by Use of Intense Acoustic Beams

    NASA Technical Reports Server (NTRS)

    Oeftering, Richard C.; Denofrio, Charles

    2003-01-01

    An improved method of selective plating of metals and possibly other materials involves the use of directed high-intensity acoustic beams. The beams, typically in the ultrasonic frequency range, can be generated by fixed-focus transducers (see figure) or by phased arrays of transducers excited, variously, by continuous waves, tone bursts, or single pulses. The nonlinear effects produced by these beams are used to alter plating processes in ways that are advantageous.

  7. Drift compression of an intense neutralized ion beam

    SciTech Connect

    Roy, P.K.; Yu, S.S.; Henestroza, E.; Anders, A.; Bieniosek, F.M.; Coleman, J.; Eylon, S.; Greenway, W.G.; Leitner, M.; Logan, B.G.; Waldron, W.L.; Welch, D.R.; Thoma, C.; Sefkow, A.B.; Gilson, E.P.; Efthimion, P.C.; Davidson, R.C.

    2004-10-25

    Longitudinal compression of a tailored-velocity, intense neutralized ion beam has been demonstrated. The compression takes place in a 1-2 m drift section filled with plasma to provide space-charge neutralization. An induction cell produces a head-to-tail velocity ramp that longitudinally compresses the neutralized beam, enhancing the beam peak current by a factor of 50 and producing a pulse duration of about 3 ns. this measurement has been confirmed independently with two different diagnostic systems.

  8. Straight low energy beam transport for intense uranium beams

    NASA Astrophysics Data System (ADS)

    Xiao, C.; Groening, L.; Vormann, H.; Mickat, S.; Hollinger, R.; Adonin, A.; Orzhekhovskaya, A.; Maier, M.; Al-Omari, H.; Barth, W.; Kester, O. K.; Yaramyshev, S.

    2015-07-01

    A new high current uranium ion source and dedicated Low Energy Beam Transport (LEBT) will be built at the GSI High Current Injector (HSI). This LEBT will be integrated into the existing complex which already comprises two branches. The paper presents the design and dynamics simulation using the TRACE-3D and TRACK code. The simulation results illustrate that this straight LEBT can transport uranium beams over a wide range of space-charge compensation, and can provide 15.4 (14.2) mA U4+ inside of the effective acceptance of the subsequent RFQ assuming the space-charge is compensated to 100% (95%).

  9. New tandem type ion source based on electron cyclotron resonance for universal source of synthesized ion beams

    SciTech Connect

    Kato, Yushi Kurisu, Yosuke; Nozaki, Dai; Yano, Keisuke; Kimura, Daiju; Kumakura, Sho; Imai, Youta; Nishiokada, Takuya; Sato, Fuminobu; Iida, Toshiyuki

    2014-02-15

    A new tandem type source has been constructed on the basis of electron cyclotron resonance (ECR) plasma for producing synthesized ion beams. We investigate feasibility and hope to realize the device which has wide range operation window in a single device to produce many kinds of ion beams based on ECR ion source (ECRIS). It is considered that ECR plasmas are necessary to be available to individual operations with different plasma parameters. Both of analysis of ion beams and investigation of plasma parameters are conducted on produced plasmas. We describe construction of the new tandem type ion source based on ECRIS with wide operation window for aiming at producing synthesized ion beams as this new source can be a universal source.

  10. Transverse-longitudinal coupling in intense beams

    SciTech Connect

    Wang, T.S.F.; Smith, L.

    1981-03-01

    The coupling between transverse and longitudinal perturbations is studied self-consistently by considering a beam of K-V distribution. The analysis is carried out within the context of linearized Vlasov-Maxwell equations and electrostatic approximation. The perturbation is assumed to be azimuthally symmetric but axially non-uniform (k/sub z/ is not equal to 0). It is shown that the coupling affects both the longitudinal and transverse modes significantly in the high density and low frequency region. Two new classes of longitudinal modes are found which would not exist if the transverse motions of particles are neglected. The effect of resistive wall impedance on beam stability is also studied. It is found that the longitudinal impedance can cause the transverse modes also to be weakly unstable.

  11. Self-Induced Transparency and Electromagnetic Pulse Compression in a Plasma or an Electron Beam under Cyclotron Resonance Conditions

    SciTech Connect

    Ginzburg, N. S.; Zotova, I. V.; Sergeev, A. S.

    2010-12-30

    Based on analogy to the well-known process of the self-induced transparency of an optical pulse propagating through a passive two-level medium we describe similar effects for a microwave pulse interacting with a cold plasma or rectilinear electron beam under cyclotron resonance condition. It is shown that with increasing amplitude and duration of an incident pulse the linear cyclotron absorption is replaced by the self-induced transparency when the pulse propagates without damping. In fact, the initial pulse decomposes to one or several solitons with amplitude and duration defined by its velocity. In a certain parameter range, the single soliton formation is accompanied by significant compression of the initial electromagnetic pulse. We suggest using the effect of self-compression for producing multigigawatt picosecond microwave pulses.

  12. Raman conversion in intense femtosecond Bessel beams in air

    NASA Astrophysics Data System (ADS)

    Scheller, Maik; Chen, Xi; Ariunbold, Gombojav O.; Born, Norman; Moloney, Jerome; Kolesik, Miroslav; Polynkin, Pavel

    2014-05-01

    We demonstrate experimentally that bright and nearly collimated radiation can be efficiently generated in air pumped by an intense femtosecond Bessel beam. We show that this nonlinear conversion process is driven by the rotational Raman response of air molecules. Under optimum conditions, the conversion efficiency from the Bessel pump into the on-axis propagating beam exceeds 15% and is limited by the onset of intensity clamping and plasma refraction on the beam axis. Our experimental findings are in excellent agreement with numerical simulations based on the standard model for the ultrafast nonlinear response of air.

  13. Aperture Effects and Mismatch Oscillations in an Intense Electron Beam

    SciTech Connect

    Harris, J R; O'Shea, P G

    2008-05-12

    When an electron beam is apertured, the transmitted beam current is the product of the incident beam current density and the aperture area. Space charge forces generally cause an increase in incident beam current to result in an increase in incident beam spot size. Under certain circumstances, the spot size will increase faster than the current, resulting in a decrease in current extracted from the aperture. When using a gridded electron gun, this can give rise to negative transconductance. In this paper, we explore this effect in the case of an intense beam propagating in a uniform focusing channel. We show that proper placement of the aperture can decouple the current extracted from the aperture from fluctuations in the source current, and that apertures can serve to alter longitudinal space charge wave propagation by changing the relative contribution of velocity and current modulation present in the beam.

  14. A room temperature electron cyclotron resonance ion source for the DC-110 cyclotron

    SciTech Connect

    Efremov, A. Bogomolov, S.; Lebedev, A.; Loginov, V.; Yazvitsky, N.

    2014-02-15

    The project of the DC-110 cyclotron facility to provide applied research in the nanotechnologies (track pore membranes, surface modification of materials, etc.) has been designed by the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research (Dubna). The facility includes the isochronous cyclotron DC-110 for accelerating the intensive Ar, Kr, Xe ion beams with 2.5 MeV/nucleon fixed energy. The cyclotron is equipped with system of axial injection and ECR ion source DECRIS-5, operating at the frequency of 18 GHz. This article reviews the design and construction of DECRIS-5 ion source along with some initial commissioning results.

  15. Stopping intense beams of internally cold molecules via centrifugal forces

    NASA Astrophysics Data System (ADS)

    Wu, Xing; Gantner, Thomas; Zeppenfeld, Martin; Chervenkov, Sotir; Rempe, Gerhard

    2016-05-01

    Cryogenic buffer-gas cooling produces intense beams of internally cold molecules. It offers a versatile source for studying collision dynamics and reaction pathways in the cold regime, and could open new avenues for controlled chemistry, precision spectroscopy, and exploration of fundamental physics. However, an efficient deceleration of these beams still presents a challenge. Here, we demonstrate that intense and continuous beams of electrically guided molecules produced by a cryogenic buffer-gas cell can be brought to a halt by the centrifugal force in a rotating frame. Various molecules (e.g. CH3F and CF3CCH) are decelerated to below 20m /s at a corresponding output intensity of ~ 6 ×109mm-2 .s-1 . In addition, our RF-resonant depletion detection shows that up to 90 % rotational-state purity can be achieved in the so-produced slow molecular beams.

  16. Limiting current of intense electron beams in a decelerating gap

    NASA Astrophysics Data System (ADS)

    Nusinovich, G. S.; Beaudoin, B. L.; Thompson, C.; Karakkad, J. A.; Antonsen, T. M.

    2016-02-01

    For numerous applications, it is desirable to develop electron beam driven efficient sources of electromagnetic radiation that are capable of producing the required power at beam voltages as low as possible. This trend is limited by space charge effects that cause the reduction of electron kinetic energy and can lead to electron reflection. So far, this effect was analyzed for intense beams propagating in uniform metallic pipes. In the present study, the limiting currents of intense electron beams are analyzed for the case of beam propagation in the tubes with gaps. A general treatment is illustrated by an example evaluating the limiting current in a high-power, tunable 1-10 MHz inductive output tube (IOT), which is currently under development for ionospheric modification. Results of the analytical theory are compared to results of numerical simulations. The results obtained allow one to estimate the interaction efficiency of IOTs.

  17. An improved high intensity recycling helium-3 beam source

    SciTech Connect

    Hedgeland, H.; Kole, P. R.; Allison, W.; Ellis, J.; Jardine, A. P.

    2009-07-15

    We describe an improved high intensity, recycling, supersonic atomic beam source. Changes address several issues previously limiting performance and reliability of the apparatus, including the use of newly available vacuum pumps and modifications to the recycling system. We achieve a source intensity of 2.5x10{sup 19} atoms/s/sr, almost twice that previously achievable during recycling. Current limits on intensity are discussed.

  18. An improved high intensity recycling helium-3 beam source.

    PubMed

    Hedgeland, H; Kole, P R; Allison, W; Ellis, J; Jardine, A P

    2009-07-01

    We describe an improved high intensity, recycling, supersonic atomic beam source. Changes address several issues previously limiting performance and reliability of the apparatus, including the use of newly available vacuum pumps and modifications to the recycling system. We achieve a source intensity of 2.5 x 10(19) atoms/s/sr, almost twice that previously achievable during recycling. Current limits on intensity are discussed. PMID:19655995

  19. Beam instrumentation for future high intense hadron accelerators at Fermilab

    SciTech Connect

    Wendt, M.; Hu, M.; Tassotto, G.; Thurman-Keup, R.; Scarpine, V.; Shin, S.; Zagel, J.; /Fermilab

    2008-08-01

    High intensity hadron beams of up to 2 MW beam power are a key element of new proposed experimental facilities at Fermilab. Project X, which includes a SCRF 8 GeV H{sup -} linac, will be the centerpiece of future HEP activities in the neutrino sector. After a short overview of this, and other proposed projects, we present the current status of the beam instrumentation activities at Fermilab with a few examples. With upgrades and improvements they can meet the requirements of the new beam facilities, however design and development of new instruments is needed, as shown by the prototype and conceptual examples in the last section.

  20. Acceleration of electrons by a tightly focused intense laser beam.

    PubMed

    Li, Jian-Xing; Zang, Wei-Ping; Li, Ya-Dong; Tian, Jian-Guo

    2009-07-01

    The recent proposal to use Weinger transformation field (WTF) [Opt. Express 17, 4959-4969 (2009)] for describing tightly focused laser beams is investigated here in detail. In order to validate the accuracy of WTF, we derive the numerical field (NF) from the plane wave spectrum method. WTF is compared with NF and Lax series field (LSF). Results show that LSF is accurate close to the beam axis and divergent far from the beam axis, and WTF is always accurate. Moreover, electron dynamics in a tightly focused intense laser beam are simulated by LSF, WTF and NF, respectively. The results obtained by WTF are shown to be accurate. PMID:19582099

  1. Dose conformation of intensity-modulated stereotactic photon beams, proton beams, and intensity-modulated proton beams for intracranial lesions

    SciTech Connect

    Baumert, Brigitta G. . E-mail: brigitta.baumert@maastro.nl; Norton, Ian A.; Lomax, Antony J.; Davis, J.B.

    2004-11-15

    Purpose: This study evaluates photon beam intensity-modulated stereotactic radiotherapy (IMSRT) based on dynamic leaf motion of a micromultileaf collimator (mMLC), proton beams, and intensity-modulated proton therapy (IMPT) with respect to target coverage and organs at risk. Methods and materials: Dose plans of 6 stereotactically treated patients were recalculated for IMSRT by use of the same field setup and an inverse planning algorithm. Proton and IMPT plans were calculated anew. Three different tumor shapes, multifocal, ovoid, and irregular, were analyzed, as well as dose to organs-at-risk (OAR) in the vicinity of the planning target volume (PTV). Dose distributions were calculated from beam-setup data for a manual mMLC for stereotactically guided conformal radiotherapy (SCRT), a dynamic mMLC for IMSRT, the spot-scanning technique for protons, and a modified spot-scanning technique for IMPT. SCRT was included for a part of the comparison. Criteria for assessment were PTV coverage, dose-volume histograms (DVH), volumes of specific isodoses, and the dose to OAR. Results: Dose conformation to the PTV is equally good for all three techniques and tumor shapes considered. The volumes of the 90% and 80% isodose were comparable for all techniques. For the 50% isodose volume, a divergence between the two modes was seen. In 3 cases, this volume is smaller for IMSRT, and in the 3 other cases, it is smaller for IMPT. This difference was even more pronounced for the volumes of the 30% isodose; IMPT shows further improvement over conventional protons. OAR in concavities (e.g., the brainstem) were similarly well spared by protons and IMSRT. IMPT spares critical organs best. Fewer proton beams are required to achieve similar results. Conclusions: The addition of intensity modulation improves the conformality of mMLC-based SCRT. Conformation of dose to the PTV is comparable for IMSRT, protons, and IMPT. Concerning the sparing of OAR, IMSRT is equivalent to IMPT, and IMPT is

  2. Space-Charge Waves and Instabilities in Intense Beams

    NASA Astrophysics Data System (ADS)

    Wang, J. G.

    1997-11-01

    Advancced accelerator applications, such as drivers for heavy ion inertial fusion, high-intensity synchrotrons for spallation neutron sources, high energy boosters, free electron lasers, high-power microwave generators, etc., require ever-increasing beam intensity. An important beam dynamics issue in such beams is the collective behavior of charged particles due to their space charge effects. This includes the phenomena of space-charge waves and instabilities excited on beams by external perturbations. It is very crucial to fully understand these phenomena in order to develop advanced accelerators for various applications. At the University of Maryland we have been conducting experimental programs to study space-charge waves and longitudinal instabilities by employing low-energy, high-current, space-charge dominated electron beams. Localized perturbations on the beams are generated from a gridded electron gun. In a conducting transport channel focused by short solenoids, these perturbations evolve into space-charge waves propagating on the beams. The wave speed is measured and many beam parameters are determined with this technique. The reflection of space-charge waves at the shoulder of an initially rectangular beam bunch is also observed. In a resistive-wall channel focused by a uniform long solenoid, the space-charge waves suffer longitudinal instability. The properties of the instabilities are studied in detail in the long wavelength range. In this talk we review our experimental results on the waves and instabilities and compare with theory.

  3. Emittance Growth in Intense Non-Circular Beams

    NASA Astrophysics Data System (ADS)

    Anderson, O. A.

    1997-05-01

    The electrostatic energy of intense beams in linear uniform focusing channels is minimized when the initial beam configuration is both uniform and round.(In the case of quadrupole focusing, this means round on the average.) Deviations from either uniformity or roundness produce free energy and emittance growth. Over the past 25 years, the consequences of beam nonuniformity have been thoroughly investigated for the case of round beams. Recently, there has been interest in more complex beam configurations such as those that occur in Heavy Ion Fusion (HIF) combiners or splitters. We discuss free energy and emittance growth for a variety of cases: (a) square beams, (b) hexagonal beams, (c) beams bounded by a quadrant or sextant of a circle, (d) rectangular beams, (e) elliptical beams, (f) pairs of beamlets, and (g) arrays of many beamlets. Cases (a) and (b) are approximations for large arrays of beamlets as proposed for HIF combiners or for negative-ion sources. Beam splitting, suggested for a particular HIF final focus scheme, leads to (c). The large emittance growth in cases (d)-(f), calculated by a new method,(O.A. Anderson, Proceedings of EPAC 96 conference.) illustrates the importance of maintaining symmetry. Practical examples are given for several cases.

  4. The generation and application of intense pulsed ion beams

    NASA Astrophysics Data System (ADS)

    Golden, J.; Kapetanakos, C. A.; Pasour, J. A.; Mahaffey, R. A.

    1981-04-01

    Means for the generation of pulsed, ultrahigh power beams of low-atomic-mass ions are considered, and potential applications of the beams in thermonuclear fusion and other applications are discussed. The intense ion beam sources represent an extension of the pulsed-power technology of relativistic electron beams, employing transmission lines powered by Marx generators to produce pulses of 25-100 nsec duration, energies of 0.1-2 MV, currents of 1 kA to 1 MA, and power levels above 1 GW. The most successful approach to intense pulsed beam generation is based on the acceleration of plasma ions within vacuum-diode-like sources involving the processes of plasma generation, ion extraction, and the suppression of the electron current, which may be accomplished by reflexing, pinching or magnetic insulation. Ion beams thus generated have been used to form transient, field-reversed ion layers and to excite high-power gas lasers. Intense ion beams are also under investigation as drivers of inertial confinement in thermonuclear reactors.

  5. On-line measurements of proton beam current from a PET cyclotron using a thin aluminum foil

    NASA Astrophysics Data System (ADS)

    Ghithan, S.; do Carmo, S. J. C.; Ferreira Marques, R.; Fraga, F. A. F.; Simões, H.; Alves, F.; Crespo, P.

    2013-07-01

    The number of cyclotrons capable of accelerating protons to about 20 MeV is increasing throughout the world. Originally aiming at the production of positron emission tomography (PET) radionuclides, some of these facilities are equipped with several beam lines suitable for scientific research. Radiobiology, radiophysiology, and other dosimetric studies can be performed using these beam lines. In this work, we measured the Bragg peak of the protons from a PET cyclotron using a stacked target consisting of several aluminum foils interleaved with polyethylene sheets, readout by in-house made transimpedance electronics. The measured Bragg peak is consistent with simulations performed using the SRIM/TRIM simulation toolkit. Furthermore, we report on experimental results aiming at measuring proton beam currents down to 10 pA using a thin aluminum foil (20-μm-thick). The aluminum was chosen for this task because it is radiation hard, it has low density and low radiation activity, and finally because it is easily available at negligible cost. This method allows for calculating the dose delivered to a target during an irradiation with high efficiency, and with minimal proton energy loss and scattering.

  6. Upgrade of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN.

    PubMed

    Toivanen, V; Bellodi, G; Dimov, V; Küchler, D; Lombardi, A M; Maintrot, M

    2016-02-01

    Linac3 is the first accelerator in the heavy ion injector chain of the Large Hadron Collider (LHC), providing multiply charged heavy ion beams for the CERN experimental program. The ion beams are produced with GTS-LHC, a 14.5 GHz electron cyclotron resonance ion source, operated in afterglow mode. Improvement of the GTS-LHC beam formation and beam transport along Linac3 is part of the upgrade program of the injector chain in preparation for the future high luminosity LHC. A mismatch between the ion beam properties in the ion source extraction region and the acceptance of the following Low Energy Beam Transport (LEBT) section has been identified as one of the factors limiting the Linac3 performance. The installation of a new focusing element, an einzel lens, into the GTS-LHC extraction region is foreseen as a part of the Linac3 upgrade, as well as a redesign of the first section of the LEBT. Details of the upgrade and results of a beam dynamics study of the extraction region and LEBT modifications will be presented. PMID:26932084

  7. Upgrade of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN

    NASA Astrophysics Data System (ADS)

    Toivanen, V.; Bellodi, G.; Dimov, V.; Küchler, D.; Lombardi, A. M.; Maintrot, M.

    2016-02-01

    Linac3 is the first accelerator in the heavy ion injector chain of the Large Hadron Collider (LHC), providing multiply charged heavy ion beams for the CERN experimental program. The ion beams are produced with GTS-LHC, a 14.5 GHz electron cyclotron resonance ion source, operated in afterglow mode. Improvement of the GTS-LHC beam formation and beam transport along Linac3 is part of the upgrade program of the injector chain in preparation for the future high luminosity LHC. A mismatch between the ion beam properties in the ion source extraction region and the acceptance of the following Low Energy Beam Transport (LEBT) section has been identified as one of the factors limiting the Linac3 performance. The installation of a new focusing element, an einzel lens, into the GTS-LHC extraction region is foreseen as a part of the Linac3 upgrade, as well as a redesign of the first section of the LEBT. Details of the upgrade and results of a beam dynamics study of the extraction region and LEBT modifications will be presented.

  8. Precision monitoring of relative beam intensity for Mu2e

    SciTech Connect

    Evans, N.J.; Kopp, S.E.; Prebys, E.; /Fermilab

    2011-04-01

    For future experiments at the intensity frontier, precise and accurate knowledge of beam time structure will be critical to understanding backgrounds. The proposed Mu2e experiment will utilize {approx}200 ns (FW) bunches of 3 x 10{sup 7} protons at 8 GeV with a bunch-to-bunch period of 1695 ns. The out-of-bunch beam must be suppressed by a factor of 10{sup -10} relative to in-bunch beam and continuously monitored. I propose a Cerenkov-based particle telescope to measure secondary production from beam interactions in a several tens of microns thick foil. Correlating timing information with beam passage will allow the determination of relative beam intensity to arbitrary precision given a sufficiently long integration time. The goal is to verify out-of-bunch extinction to the level 10{sup -6} in the span of several seconds. This will allow near real-time monitoring of the initial extinction of the beam resonantly extracted from Fermilabs Debuncher before a system of AC dipoles and collimators, which will provide the final extinction. The effect on beam emittance is minimal, allowing the necessary continuous measurement. I will present the detector design and some concerns about bunch growth during the resonant extraction.

  9. Point Scanning Microscope with Adaptive Illumination Beam Intensity

    NASA Astrophysics Data System (ADS)

    Das, Abhijit; Boruah, B. R.

    2011-10-01

    In this paper we describe a point scanning optical microscope where the illumination beam can be programmably controlled in real time using a liquid crystal spatial light modulator (LCSLM). With an appropriate pattern displayed on the LCSLM, the device can be made to act as a binary diffraction hologram. In the proposed microscope the illumination beam is in fact the +1 order beam diffracted from the binary hologram. By displaying a sequence of binary holograms it is possible to make a beam scanning, similar to a conventional scanning microscope. Here we use a computer generated holography technique to compute the binary holograms which facilitate complete control of the amplitude and phase profile of the illumination beam. In a number of microscopy applications using reflected light, the reflectivity of the sample plane may differ from region to region. Therefore if a single illumination beam intensity is used for the whole sample plane, then the regions with less reflectivity will be imaged with poor signal to noise ratio. In our proposed microscope the sample plane is first imaged to determine the regions of weak reflectivity. Holograms are then computed to make the illumination beam adapt to the reflectivity variations in the given sample plane. The image obtained with the modified set of holograms have superior signal to noise ratio all over, relative to a conventional point scanning microscope with a fixed intensity illumination beam. In this paper we present some preliminary results using the proposed setup.

  10. Nonlinear dynamics of optical absorption of intense beams

    NASA Astrophysics Data System (ADS)

    Corbett, D.; van Oosten, C. L.; Warner, M.

    2008-07-01

    On traversing materials with absorbing dyes, weak optical beams decay exponentially (a Beer profile), while intense beams develop in time a profile that is spatially linear until at great depth it becomes spatially exponential. This anomalous, deep penetration, due to photobleaching of surface layers, is important for heavy dye loading and intense beams, for instance in photo-actuation. We address the problem of the evolution in time from initial Beer’s Law to a finally deeply-penetrating optical profile in dyes. Our largely analytic solution of the coupled, nonlinear, partial differential equations governing the spatiotemporal decay of the Poynting flux and the nonlinear population dynamics of the photo-active molecules under intense irradiation has application to optomechanical devices.

  11. Core-halo issues for a very high intensity beam

    SciTech Connect

    Nghiem, P. A. P.; Chauvin, N.; Uriot, D.

    2014-02-17

    The relevance of classical parameters like beam emittance and envelope used to describe a particle beam is questioned in case of a high intensity accelerator. In the presence of strong space charge effects that affect the beam differently following its density, the much less dense halo part behaves differently from the much denser core part. A method for precisely determining the core-halo limit is proposed, that allows characterizing the halo and the core independently. Results in 1D case are given and discussed. Expected developments extending the method to 2D, 4D, or 6D phase spaces are examined.

  12. Physics design of linear accelerators for intense ion beams

    SciTech Connect

    Wangler, T.P.

    1988-01-01

    Advances in the physics and technology of linear accelerators for intense ion beams are leading to new methods for the design of such machines. The physical effects that limit beam current and brightness are better understood and provide the criteria for choosing the rf frequency and for determining optimum focusing configurations to control longitudinal and transverse emittances. During the past decade, the use of developments such as the radio-frequency quadrupole, multiple beams, funneling, ramped-field linac tanks, and self-matching linac tanks is leading to greater design flexibility and improved performance capabilities. 39 refs., 3 tabs., 1 fig.

  13. Suppression of current fluctuations in an intense electron beam

    SciTech Connect

    Harris, J. R.; Lewellen, J. W.

    2010-10-15

    When an intense beam encounters an aperture, the transmitted current depends on the properties of the beam and the transport channel, as well as those of the aperture itself. In some cases, an increase in the incident beam current will be exactly compensated by an increase in the incident beam area, so that the current density at the aperture remains unchanged. When this occurs, the transmitted beam current becomes independent of changes in the incident beam current, providing a passive means for suppressing current fluctuations in the beam. In this article, a key requirement for the existence of this condition is derived. This requirement is shown to be fulfilled in the case of an idealized uniform focusing channel in the small-signal limit, but to be violated when the current fluctuations are not small. Even in this case, the apertured transport system retains the ability to suppress--but not totally eliminate--fluctuations in the transmitted beam current for a wide range of incident beam currents.

  14. Intense ion beam neutralization using underdense background plasma

    SciTech Connect

    Berdanier, William; Roy, Prabir K.; Kaganovich, Igor

    2015-01-15

    Producing an overdense background plasma for neutralization purposes with a density that is high compared to the beam density is not always experimentally possible. We show that even an underdense background plasma with a small relative density can achieve high neutralization of intense ion beam pulses. Using particle-in-cell simulations, we show that if the total plasma electron charge is not sufficient to neutralize the beam charge, electron emitters are necessary for effective neutralization but are not needed if the plasma volume is so large that the total available charge in the electrons exceeds that of the ion beam. Several regimes of possible underdense/tenuous neutralization plasma densities are investigated with and without electron emitters or dense plasma at periphery regions, including the case of electron emitters without plasma, which does not effectively neutralize the beam. Over 95% neutralization is achieved for even very underdense background plasma with plasma density 1/15th the beam density. We compare results of particle-in-cell simulations with an analytic model of neutralization and find close agreement with the particle-in-cell simulations. Further, we show experimental data from the National Drift Compression experiment-II group that verifies the result that underdense plasma can neutralize intense heavy ion beams effectively.

  15. A conceptual design for a primary cyclotron for the ISL radioactive beam project

    SciTech Connect

    Clark, D.J.

    1992-07-01

    A design for a 600 MeV proton cyclotron is described. Features include a single stage with external ion source, a normal conducting magnet coil with 2 T peak field in the hills, and dees in valleys. The design can be extended to 800 and 1000 MeV.

  16. Realization of a phase bunching effect for minimization of beam phase width in a central region of an AVF cyclotron

    NASA Astrophysics Data System (ADS)

    Miyawaki, Nobumasa; Fukuda, Mitsuhiro; Kurashima, Satoshi; Okumura, Susumu; Kashiwagi, Hirotsugu; Nara, Takayuki; Ishibori, Ikuo; Yoshida, Ken-ichi; Yokota, Watalu; Nakamura, Yoshiteru; Arakawa, Kazuo; Kamiya, Tomihiro

    2011-04-01

    A phase bunching effect has been achieved for the first time using a rising slope of the dee voltage waveform produced at the first acceleration gap between the RF shielding cover of the inflector and the puller in the new central region of the JAEA AVF cyclotron. The feasibility of the phase bunching effect in the central region for a two-dee system with a span angle of 86° in three acceleration harmonic modes was assessed by a simple geometrical analysis of particle trajectories and a three-dimensional beam orbit simulation using the calculated electric field and a measured magnetic field. The simulation indicated that the initial beam phase width of 40 RF degrees is compressed to 11 RF degrees (about 28% of the initial phase width) in the second harmonic mode. A phase width of 1.5 RF degrees FWHM for a 260 MeV 20Ne7+ beam accelerated in the second harmonic mode was observed when using a 4 mm phase slit gap. The phase width reduction was considerably enhanced by the bunching effect, compared with the beam phase width of 7.3 RF degrees FWHM in the same harmonic mode for a 10 MeV H+ beam accelerated in the original central region. The ratio of the beam current for the 1.5 RF degrees FWHM phase width with 4 mm phase slit gap restriction to the full beam current without the phase slit was drastically improved to 80%, while the beam current was less than 1% of the full beam when narrowing the phase slit gap to obtain the 7.3 RF degrees FWHM phase width in the original central region.

  17. Internal dynamics of intense twin beams and their coherence

    PubMed Central

    Peřina, Jan; Haderka, Ondřej; Allevi, Alessia; Bondani, Maria

    2016-01-01

    The dynamics of intense twin beams in pump-depleted parametric down-conversion is studied. A generalized parametric approximation is suggested to solve the quantum model. Its comparison with a semiclassical model valid for larger twin-beam intensities confirms its applicability. The experimentally observed maxima in the spectral and spatial intensity auto- and cross- correlation functions depending on pump power are explained in terms of different speeds of the (back-) flow of energy between the individual down-converted modes and the corresponding pump modes. This effect is also responsible for the gradual replacement of the initial exponential growth of the down-converted fields by the linear one. Furthermore, it forms a minimum in the curve giving the effective number of twin-beam modes. These effects manifest a tight relation between the twin-beam coherence and its internal structure, as clearly visible in the model. Multiple maxima in the intensity correlation functions originating in the oscillations of energy flow between the pump and down-converted modes are theoretically predicted. PMID:26924749

  18. Experimental and numerical study of high intensity argon cluster beams

    SciTech Connect

    Korobeishchikov, N. G.; Kalyada, V. V.; Shmakov, A. A.; Zarvin, A. E.; Skovorodko, P. A.

    2014-12-09

    Experimental and numerical investigations of expansion of argon with homogeneous condensation in supersonic conical nozzle and in free jet behind it were carried out. Optimal parameters (stagnation pressure, nozzle-skimmer distance) for the formation of cluster beam with maximum intensity were determined. Two available models for nonequilibrium nucleation were tested. The numerical results are in satisfactory agreement with the measured data.

  19. Internal dynamics of intense twin beams and their coherence.

    PubMed

    Peřina, Jan; Haderka, Ondřej; Allevi, Alessia; Bondani, Maria

    2016-01-01

    The dynamics of intense twin beams in pump-depleted parametric down-conversion is studied. A generalized parametric approximation is suggested to solve the quantum model. Its comparison with a semiclassical model valid for larger twin-beam intensities confirms its applicability. The experimentally observed maxima in the spectral and spatial intensity auto- and cross- correlation functions depending on pump power are explained in terms of different speeds of the (back-) flow of energy between the individual down-converted modes and the corresponding pump modes. This effect is also responsible for the gradual replacement of the initial exponential growth of the down-converted fields by the linear one. Furthermore, it forms a minimum in the curve giving the effective number of twin-beam modes. These effects manifest a tight relation between the twin-beam coherence and its internal structure, as clearly visible in the model. Multiple maxima in the intensity correlation functions originating in the oscillations of energy flow between the pump and down-converted modes are theoretically predicted. PMID:26924749

  20. Full characterization of an intense pulsed hyperthermal molecular beam

    SciTech Connect

    Watanabe, D.; Che, D.-C.; Fukuyama, T.; Hashinokuchi, M.; Teraoka, Y.; Kasai, T.

    2005-05-15

    A molecular beam technique for generating an intense pulsed hyperthermal molecular beam (pulsed HTMB) was developed. The beam source consists of a pulse valve, a cooling-water bottle that protects the pulse valve from heat transfer of the high temperature nozzle, and a nozzle with a heater. The point was a pulse-valve operation with the high temperature nozzle which was 30-mm long and was made of pyrolytic boron nitride. The pulsed HTMB of HCl was practically generated. The total beam intensity of the pulsed HTMB was measured by a quadrupole mass spectrometer. It was determined that the beam intensity of the pulsed HTMB was two orders of magnitude larger than that obtained in continuous-HTMB conditions. The pulsed HTMB of HCl was fully characterized by means of (2+1) resonance-enhanced multiphoton ionization and ion time-of-flight techniques. We found that the velocity distribution of the pulsed HTMB was well expressed as supersonic molecular beams. At the highest nozzle temperature of 1400 K, the mean translational energy value of HCl molecules was 1.38 eV. The translational energy distribution of the pulsed HTMB covered a range from 0.8 to 1.6 eV. The fraction of higher translational energy molecules greater than 1.0 eV was 80% in the 1400 K nozzle. The rotational state distributions of HCl molecules in the pulsed HTMB were expressed as the Boltzmann distribution. While the rotational temperature decreased by an adiabatic expansion of the beam, the vibrational temperature, which was determined by the ratio of the ground-state population to the excited state one, almost equaled the nozzle temperature.

  1. Intense Muon Beams for Experiments at Project X

    SciTech Connect

    C.M. Ankenbrandt, R.P. Johnson, C. Y. Yoshikawa, V.S. Kashikhin, D.V. Neuffer, J. Miller, R.A. Rimmer

    2011-03-01

    A coherent approach for providing muon beams to several experiments for the intensity-frontier program at Project X is described. Concepts developed for the front end of a muon collider/neutrino factory facility, such as phase rotation and ionization cooling, are applied, but with significant differences. High-intensity experiments typically require high-duty-factor beams pulsed at a time interval commensurate with the muon lifetime. It is challenging to provide large RF voltages at high duty factor, especially in the presence of intense radiation and strong magnetic fields, which may preclude the use of superconducting RF cavities. As an alternative, cavities made of materials such as ultra-pure Al and Be, which become very good –but not super– conductors at cryogenic temperatures, can be used.

  2. Numerical phase retrieval from beam intensity measurements in three planes

    NASA Astrophysics Data System (ADS)

    Bruel, Laurent

    2003-05-01

    A system and method have been developed at CEA to retrieve phase information from multiple intensity measurements along a laser beam. The device has been patented. Commonly used devices for beam measurement provide phase and intensity information separately or with a rather poor resolution whereas the MIROMA method provides both at the same time, allowing direct use of the results in numerical models. Usual phase retrieval algorithms use two intensity measurements, typically the image plane and the focal plane (Gerschberg-Saxton algorithm) related by a Fourier transform, or the image plane and a lightly defocus plane (D.L. Misell). The principal drawback of such iterative algorithms is their inability to provide unambiguous convergence in all situations. The algorithms can stagnate on bad solutions and the error between measured and calculated intensities remains unacceptable. If three planes rather than two are used, the data redundancy created confers to the method good convergence capability and noise immunity. It provides an excellent agreement between intensity determined from the retrieved phase data set in the image plane and intensity measurements in any diffraction plane. The method employed for MIROMA is inspired from GS algorithm, replacing Fourier transforms by a beam-propagating kernel with gradient search accelerating techniques and special care for phase branch cuts. A fast one dimensional algorithm provides an initial guess for the iterative algorithm. Applications of the algorithm on synthetic data find out the best reconstruction planes that have to be chosen. Robustness and sensibility are evaluated. Results on collimated and distorted laser beams are presented.

  3. Intense Ion Beam for Warm Dense Matter Physics

    SciTech Connect

    Coleman, Joshua Eugene

    2008-05-23

    The Neutralized Drift Compression Experiment (NDCX) at Lawrence Berkeley National Laboratory is exploring the physical limits of compression and focusing of ion beams for heating material to warm dense matter (WDM) and fusion ignition conditions. The NDCX is a beam transport experiment with several components at a scale comparable to an inertial fusion energy driver. The NDCX is an accelerator which consists of a low-emittance ion source, high-current injector, solenoid matching section, induction bunching module, beam neutralization section, and final focusing system. The principal objectives of the experiment are to control the beam envelope, demonstrate effective neutralization of the beam space-charge, control the velocity tilt on the beam, and understand defocusing effects, field imperfections, and limitations on peak intensity such as emittance and aberrations. Target heating experiments with space-charge dominated ion beams require simultaneous longitudinal bunching and transverse focusing. A four-solenoid lattice is used to tune the beam envelope to the necessary focusing conditions before entering the induction bunching module. The induction bunching module provides a head-to-tail velocity ramp necessary to achieve peak axial compression at the desired focal plane. Downstream of the induction gap a plasma column neutralizes the beam space charge so only emittance limits the focused beam intensity. We present results of beam transport through a solenoid matching section and simultaneous focusing of a singly charged K{sup +} ion bunch at an ion energy of 0.3 MeV. The results include a qualitative comparison of experimental and calculated results after the solenoid matching section, which include time resolved current density, transverse distributions, and phase-space of the beam at different diagnostic planes. Electron cloud and gas measurements in the solenoid lattice and in the vicinity of intercepting diagnostics are also presented. Finally, comparisons

  4. Transport of intense beams of highly charged ions

    NASA Astrophysics Data System (ADS)

    Winkler, M.; Gammino, S.; Ciavola, G.; Celona, L.; Spadtke, P.; Tinschert, K.

    2005-10-01

    The new generation of ion sources delivers beams with intensities of several mA. This requires a careful design of the analysing system and the low-energy beam transport (LEBT) from the source to the subsequent systems. At INFN-LNS, high intensity proton sources (TRIPS [L. Celona, G. Ciavola, S. Gammino et al ., Rev. Sci. Instrum. 75(5) 1423 (2004)], PM-TRIPS [G. Ciavola, L. Celona, S. Gammino et al ., Rev. Sci. Instrum. 75(5) 1453 (2004)]) as well as ECR ion sources for the production of highly charged high-intensity heavy ion beams are developed (SERSE [S. Gammino, G. Ciavola, L. Celona et al ., Rev. Sci. Instrum. 72(11) 4090 (2001), and references therein], GyroSERSE [S. Gammino et al ., Rev. Sci. Instrum. 75(5) 1637 (2004)], MS-ECRIS [G. Ciavola et al ., (2005), 11th Int. Conf. on Ion Sources, Caen, (in press)]). In this paper, we present ion-optical design studies of various LEBT systems for ion-sources devoted to the production of intense beams. Calculations were performed using the computer codes GIOS [H. Wollnik, J. Brezina and M. Berz, NIM A 258 (1987)], GICO [M. Berz, H.C. Hoffmann, and H. Wollnik, NIM A 258 (1987)], and TRANSPORT [K.L. Brown, F. Rothacker and D.C. Carey, SLAC-R-95-462, Fermilab-Pub-95/069, UC-414 (1995)]. Simulations take into account the expected phase space growth of the beam emittance due to space-charge effects and image aberrations introduced by the magnetic elements.

  5. Collective Temperature Anisotropy Instabilities in Intense Charged Particle Beams

    NASA Astrophysics Data System (ADS)

    Startsev, Edward

    2006-10-01

    Periodic focusing accelerators, transport systems and storage rings have a wide range of applications ranging from basic scientific research in high energy and nuclear physics, to applications such as ion-beam-driven high energy density physics and fusion, and spallation neutron sources. Of particular importance at the high beam currents and charge densities of practical interest, are the effects of the intense self fields produced by the beam space charge and current on determining the detailed equilibrium, stability and transport properties. Charged particle beams confined by external focusing fields represent an example of nonneutral plasma. A characteristic feature of such plasmas is the non-uniformity of the equilibrium density profiles and the nonlinearity of the self fields, which makes detailed analytical investigation very difficult. The development and application of advanced numerical tools such as eigenmode codes [1] and Monte-Carlo particle simulation methods [2] are often the only tractable approach to understand the underlying physics of different instabilities familiar in electrically neutral plasmas which may cause a degradation in beam quality. Two such instabilities are the electrostatic Harris instability [2] and the electromagnetic Weibel instability [1], both driven by a large temperature anisotropy which develops naturally in accelerators. The beam acceleration causes a large reduction in the longitudinal temperature and provides the free energy to drive collective temperature anisotropy instabilities. Such instabilities may lead to an increase in the longitudinal velocity spread, which will make focusing the beam difficult, and may impose a limit on the beam luminosity and the minimum spot size achievable in focusing experiments. This paper reviews recent advances in the theory and simulation of collective instabilities in intense charged particle beams caused by temperature anisotropy. We also describe new simulation tools that have been

  6. Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trap

    SciTech Connect

    Nikolaev, A. G.; Savkin, K. P.; Oks, E. M.; Vizir, A. V.; Yushkov, G. Yu.; Vodopyanov, A. V.; Izotov, I. V.; Mansfeld, D. A.

    2012-02-15

    A method for generating high charge state heavy metal ion beams based on high power microwave heating of vacuum arc plasma confined in a magnetic trap under electron cyclotron resonance conditions has been developed. A feature of the work described here is the use of a cusp magnetic field with inherent ''minimum-B'' structure as the confinement geometry, as opposed to a simple mirror device as we have reported on previously. The cusp configuration has been successfully used for microwave heating of gas discharge plasma and extraction from the plasma of highly charged, high current, gaseous ion beams. Now we use the trap for heavy metal ion beam generation. Two different approaches were used for injecting the vacuum arc metal plasma into the trap - axial injection from a miniature arc source located on-axis near the microwave window, and radial injection from sources mounted radially at the midplane of the trap. Here, we describe preliminary results of heating vacuum arc plasma in a cusp magnetic trap by pulsed (400 {mu}s) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

  7. Excitation of electrostatic ion-cyclotron waves by an ion beam in a two-ion component plasma

    SciTech Connect

    Sharma, Jyotsna; Sharma, Suresh C.

    2010-12-15

    An ion beam propagating through a magnetized plasma cylinder containing electrons, light positive potassium ions (K{sup +}), and heavy positive cesium ions (Cs{sup +}) drives electrostatic ion cyclotron (EIC) waves to instability via Cerenkov interaction. Two EIC wave modes are present, the K{sup +} and Cs{sup +} modes. The unstable wave frequencies and the growth rate of both the light positive ion and heavy positive ion modes increase with an increase in their relative ion concentrations. The growth rate of both the unstable modes (K{sup +} and Cs{sup +}) scales one-third power of the beam density. The real part of the frequency of both the unstable modes (K{sup +} and Cs{sup +}) increases with the beam energy and scales as almost one-half power of the beam energy. Numerical calculations of the growth rate and mode frequencies have been carried out for the parameters of the experiment of Suszcynsky et al. [J. Geophys. Res. 94, 8966 (1989)]. It is found that the unstable wave frequencies of both the light positive ion and heavy positive ion modes increase with the magnetic fields in accordance with the experimental observations.

  8. High intensity positron beam and angular correlation experiments at Livermore

    SciTech Connect

    Howell, R.H.; Rosenberg, I.J.; Meyer, P.; Fluss, M.J.

    1985-03-01

    A positron beam apparatus that produces a variable energy positron beam with sufficient intensity to perform new positron experiments in an ultrahigh vacuum environment has been installed at the Lawrence Livermore 100 MeV electron linac. We have installed two large area position sensitive gamma-ray detectors to measure angular correlations in two dimensions and a separate highly collimated detector to measure positronium energy distributions by time-of-flight velocity determination. Data from measurements on single crystals of Cu will be described.

  9. HIGH ENERGY DENSITY PHYSICS EXPERIMENTS WITH INTENSE HEAVY ION BEAMS

    SciTech Connect

    Henestroza, E.; Leitner, M.; Logan, B.G.; More, R.M.; Roy, P.K.; Ni, P.; Seidl, P.A.; Waldron, W.L.; Barnard, J.J.

    2010-03-16

    The US heavy ion fusion science program has developed techniques for heating ion-beam-driven warm dense matter (WDM) targets. The WDM conditions are to be achieved by combined longitudinal and transverse space-charge neutralized drift compression of the ion beam to provide a hot spot on the target with a beam spot size of about 1 mm, and pulse length about 1-2 ns. As a technique for heating volumetric samples of matter to high energy density, intense beams of heavy ions are capable of delivering precise and uniform beam energy deposition dE/dx, in a relatively large sample size, and the ability to heat any solid-phase target material. Initial experiments use a 0.3 MeV K+ beam (below the Bragg peak) from the NDCX-I accelerator. Future plans include target experiments using the NDCX-II accelerator, which is designed to heat targets at the Bragg peak using a 3-6 MeV lithium ion beam. The range of the beams in solid matter targets is about 1 micron, which can be lengthened by using porous targets at reduced density. We have completed the fabrication of a new experimental target chamber facility for WDM experiments, and implemented initial target diagnostics to be used for the first target experiments in NDCX-1. The target chamber has been installed on the NDCX-I beamline. The target diagnostics include a fast multi-channel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. Initial WDM experiments will heat targets by compressed NDCX-I beams and will explore measurement of temperature and other target parameters. Experiments are planned in areas such as dense electronegative targets, porous target homogenization and two-phase equation of state.

  10. HIGH ENERGY DENSITY PHYSICS EXPERIMENTS WITH INTENSE HEAVY ION BEAMS

    SciTech Connect

    Bieniosek, F.M.; Henestroza, E.; Leitner, M.; Logan, B.G.; More, R.M.; Roy, P.K.; Ni, P.; Seidl, P.A.; Waldron, W.L.; Barnard, J.J.

    2008-08-01

    The US heavy ion fusion science program has developed techniques for heating ion-beam-driven warm dense matter (WDM) targets. The WDM conditions are to be achieved by combined longitudinal and transverse space-charge neutralized drift compression of the ion beam to provide a hot spot on the target with a beam spot size of about 1 mm, and pulse length about 1-2 ns. As a technique for heating volumetric samples of matter to high energy density, intense beams of heavy ions are capable of delivering precise and uniform beam energy deposition dE/dx, in a relatively large sample size, and the ability to heat any solid-phase target material. Initial experiments use a 0.3 MeV K+ beam (below the Bragg peak) from the NDCX-I accelerator. Future plans include target experiments using the NDCX-II accelerator, which is designed to heat targets at the Bragg peak using a 3-6 MeV lithium ion beam. The range of the beams in solid matter targets is about 1 micron, which can be lengthened by using porous targets at reduced density. We have completed the fabrication of a new experimental target chamber facility for WDM experiments, and implemented initial target diagnostics to be used for the first target experiments in NDCX-1. The target chamber has been installed on the NDCX-I beamline. The target diagnostics include a fast multi-channel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. Initial WDM experiments will heat targets by compressed NDCX-I beams and will explore measurement of temperature and other target parameters. Experiments are planned in areas such as dense electronegative targets, porous target homogenization and two-phase equation of state.

  11. Compact antenna for two-dimensional beam scan in the JT-60U electron cyclotron heating/current drive system

    SciTech Connect

    Moriyama, S.; Kajiwara, K.; Takahashi, K.; Kasugai, A.; Seki, M.; Ikeda, Y.; Fujii, T.

    2005-11-15

    A compact antenna system was designed and fabricated to enable millimeter-wave beam scanning in the toroidal and poloidal directions of the JT-60U tokamak for electron cyclotron heating (ECH) and electron cyclotron current drive (ECCD) experiments. The antenna consists of a fast movable flat mirror mounted on the tokamak vacuum vessel and a rotary focusing mirror attached at the end of the waveguide that is supported from outside the vacuum vessel. This separate support concept enables a compact structure inside a shallow port (0.68x0.54x0.2 m) that is shared with a subport for an independent diagnostic system. During a plasma shot, the flat mirror is driven by a servomotor with a 3-m-long drive shaft to reduce the influence of the high magnetic field on the motor. The focusing mirror is rotated by a simple mechanism utilizing a push rod and an air cylinder. The antenna has been operated reliably for 3 years after a small improvement to the rotary drive mechanism. It has made significant contributions to ECH and ECCD experiments, especially the current profile control in JT-60U.

  12. Studies of extraction and transport system for highly charged ion beam of 18 GHz superconducting electron cyclotron resonance ion source at Research Center for Nuclear Physics.

    PubMed

    Yorita, T; Hatanaka, K; Fukuda, M; Ueda, H; Yasuda, Y; Morinobu, S; Tamii, A; Kamakura, K

    2014-02-01

    An 18 GHz superconducting electron cyclotron resonance ion source is installed to increase beam currents and to extend the variety of ions especially for highly charged heavy ions which can be accelerated by cyclotrons of Research Center for Nuclear Physics (RCNP), Osaka University. The beam production developments of several ions from B to Xe have been already done [T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 79, 02A311 (2008) and T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 81, 02A332 (2010)] and the further studies for those beam extraction and its transport have been done in order to increase the beam current more. The plasma electrode, extraction electrode, and einzel lens are modified. Especially extraction electrode can be applied minus voltage for the beam extraction and it works well to improve the extracted beam current. The extraction voltage dependences of transmission and emittance also have been studied for beam current improvement which is injected into azimuthally varying field cyclotron at RCNP. PMID:24593475

  13. Studies of extraction and transport system for highly charged ion beam of 18 GHz superconducting electron cyclotron resonance ion source at Research Center for Nuclear Physics

    SciTech Connect

    Yorita, T. Hatanaka, K.; Fukuda, M.; Ueda, H.; Yasuda, Y.; Morinobu, S.; Tamii, A.; Kamakura, K.

    2014-02-15

    An 18 GHz superconducting electron cyclotron resonance ion source is installed to increase beam currents and to extend the variety of ions especially for highly charged heavy ions which can be accelerated by cyclotrons of Research Center for Nuclear Physics (RCNP), Osaka University. The beam production developments of several ions from B to Xe have been already done [T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 79, 02A311 (2008) and T. Yorita, K. Hatanaka, M. Fukuda, M. Kibayashi, S. Morinobu, H.Okamura, and A. Tamii, Rev. Sci. Instrum. 81, 02A332 (2010)] and the further studies for those beam extraction and its transport have been done in order to increase the beam current more. The plasma electrode, extraction electrode, and einzel lens are modified. Especially extraction electrode can be applied minus voltage for the beam extraction and it works well to improve the extracted beam current. The extraction voltage dependences of transmission and emittance also have been studied for beam current improvement which is injected into azimuthally varying field cyclotron at RCNP.

  14. Survey of Collective Instabilities and Beam-Plasma Interactions in Intense Heavy Ion Beams

    SciTech Connect

    Davidson, Ronald C.; Dorf, Mikhail A.; Kaganovich, Igor D.; Qin, Hong; Startsev, Edward A.; Rose, David V.; Lund, Steven M.; Welch, Dale R.; Sefkow, Adam

    2008-06-19

    This paper presents a survey of the present theoretical understanding based on advanced analytical and numerical studies of collective processes and beam-plasma interactions in intense heavy ion beams for applications to ion-beam-driven high energy density physics and heavy ion fusion. The topics include: discussion of the conditions for quiescent beam propagation over long distances; and the electrostatic Harris instability and the transverse electromagnetic Weibel instability in highly anisotropic, intense one-component ion beams. In the longitudinal drift compression and transverse compression regions, collective processes associated with the interaction of the intense ion beam with a charge-neutralizing background plasma are described, including the electrostatic electron-ion two-stream instability, the multispecies electromagnetic Weibel instability, and collective excitations in the presence of a solenoidal magnetic field. The effects of a velocity tilt on reducing two-stream instability growth rates are also discussed. Operating regimes are identified where the possible deleterious effects of collective processes on beam quality are minimized.

  15. Emittance of positron beams produced in intense laser plasma interaction

    SciTech Connect

    Chen Hui; Hazi, A.; Link, A.; Anderson, S.; Gronberg, J.; Izumi, N.; Tommasini, R.; Wilks, S.; Sheppard, J. C.; Meyerhofer, D. D.; Baldis, H. A.; Marley, E.; Park, J.; Williams, G. J.; Fedosejev, R.; Kerr, S.

    2013-01-15

    The first measurement of the emittance of intense laser-produced positron beams has been made. The emittance values were derived through measurements of positron beam divergence and source size for different peak positron energies under various laser conditions. For one of these laser conditions, we used a one dimensional pepper-pot technique to refine the emittance value. The laser-produced positrons have a geometric emittance between 100 and 500 mm{center_dot}mrad, comparable to the positron sources used at existing accelerators. With 10{sup 10}-10{sup 12} positrons per bunch, this low emittance beam, which is quasi-monoenergetic in the energy range of 5-20 MeV, may be useful as an alternative positron source for future accelerators.

  16. Excitation of the surface flute waves in electron cyclotron frequency range by internal rotating electron beam in a coaxial waveguide

    NASA Astrophysics Data System (ADS)

    Blednov, O.; Girka, I.; Girka, V.; Pavlenko, I.; Sydora, R.

    2014-12-01

    The initial stage of interaction between a gyrating beam of electrons, which move along Larmor orbits in a narrow gap between a cylindrical plasma layer and an internal screen of a metal coaxial waveguide and electromagnetic eigen waves, is studied theoretically. These waves are extraordinary polarized ones; they propagate along the azimuthal angle across an axial external steady magnetic field in the electron cyclotron frequency range. The numerical analysis shows that the excitation process is stable enough in respect to changing plasma waveguide parameters. The wider the plasma layer, the broader the range of plasma waveguide parameters within which effective wave excitation takes place. The main influence on the excitation of these modes is performed by the applied axial magnetic field, namely: its increase leads to an increase of growth rate and a broadening of the range of the waveguide parameters within which wave excitation is effective.

  17. Spatially resolved measurements of electron cyclotron resonance ion source beam profile characteristics

    SciTech Connect

    Panitzsch, Lauri; Stalder, Michael; Wimmer-Schweingruber, Robert F.

    2011-03-15

    Simulations predict that the concentric rings and the triangular structures in the profiles of strongly focused ion beams that are found in different experiments should be dominated by ion species with the same or at least similar m/q-ratio. To verify these theoretical predictions we have tuned our ECR ion source to deliver a beam consisting of multiple ion species whose particular m/q-depending focusing ranges from weakly focused to overfocused. We then recorded spatially resolved charge-state distributions of the beam profile at characteristic positions in the plane perpendicular to the beam line. The results validate theoretical predictions and are summarized in this paper. To achieve the required beam profile characteristics we moved the extraction along the beam line to achieve stronger focusing than by only changing the extraction voltage. To fit the regions of interest of the beam profile into the transmission area of the sector magnet, we steered the beam by moving the extraction in the plane perpendicular to the beam axis. The results of both investigations, beam focusing and beam steering by using a 3D-movable extraction, are also reported in this paper. A brief overview of the new beam monitor extensively used during these measurements, the Faraday cup array, is also given.

  18. Facility for intense diagnostic neutral beam (IDNB) development

    SciTech Connect

    Kasik, R.J.; Hinckley, W.B.; Bartsch, R.R.; Rej, D.J.; Henins, I.; Greenly, J.B.

    1993-08-01

    An intense, pulsed neutral beam source is under development for use as a probe beam on hot, burning plasmas such as in the international thermonuclear experimental reactor (ITER) which is presently in the planning stage. A pulsed, neutral hydrogen beam of 10s of kilo amperes of current can have an alpha particle, charge-exchange-recombination-spectroscopy (alpha-CHERS) signal-to-noise ratio of {approximately} 10. This beam would allow the measurement, on a single pulse of a few hundred nanoseconds duration, of the local alpha particle distribution function as well as other features of the tokamak plasma such as current density profile, impurity density, and microturbulence spectrum. The cross-sections for the CHERS diagnostic dictate operation with proton energies greater than {approximately}50keV. A pulsed neutral hydrogen source of this voltage and intensity can be achieved by neutralizing the ion flux from a magnetized ion-diode. The cross-sections for attachment and stripping, when coupled with scaling from Child-Langmiur, space-charge-limited, ion-current flow imply operation below - 100keV for maximum neutral fluence. The development of a flashover-anode, ion source for forthcoming evaluation of a neutralizing section is described below. This source operates in the accelerator voltage range 70 to 100keV. Eventually, the flashover-anode, magnetized ion-diode will be replaced with a plasma-anode, magnetized ion-diode.

  19. Transport of intense ion beams and space charge compensation issues in low energy beam lines (invited)

    SciTech Connect

    Chauvin, N.; Delferriere, O.; Duperrier, R.; Gobin, R.; Nghiem, P. A. P.; Uriot, D.

    2012-02-15

    Over the last few years, the interest of the international scientific community for high power accelerators in the megawatt range has been increasing. For such machines, the ion source has to deliver a beam intensity that ranges from several tens up to a hundred of mA. One of the major challenges is to extract and transport the beam while minimizing the emittance growth and optimizing its injection into the radio frequency quadrupole. Consequently, it is crucial to perform precise simulations and cautious design of the low energy beam transport (LEBT) line. In particular, the beam dynamics calculations have to take into account not only the space charge effects but also the space charge compensation of the beam induced by ionization of the residual gas. The physical phenomena occurring in a high intensity LEBT and their possible effects on the beam are presented, with a particular emphasis on space charge compensation. Then, beam transport issues in different kind of LEBTs are briefly reviewed. The SOLMAXP particle-in-cell code dedicated to the modeling of the transport of charge particles under a space charge compensation regime is described. Finally, beam dynamics simulations results obtained with SOLMAXP are presented in the case of international fusion materials irradiation facility injector.

  20. Dosimetry for ocular proton beam therapy at the Harvard Cyclotron Laboratory based on the ICRU Report 59.

    PubMed

    Newhauser, W D; Burns, J; Smith, A R

    2002-09-01

    The Massachusetts General Hospital, the Harvard Cyclotron Laboratory (HCL), and the Massachusetts Eye and Ear Infirmary have treated almost 3000 patients with ocular disease using high-energy external-beam proton radiation therapy since 1975. The absorbed dose standard for ocular proton therapy beams at HCL was based on a fluence measurement with a Faraday cup (FC). A majority of proton therapy centers worldwide, however, use an absorbed dose standard that is based on an ionization chamber (IC) technique. The ion chamber calibration is deduced from a measurement in a reference 60Co photon field together with a calculated correction factor that takes into account differences in a chamber's response in 60Co and proton fields. In this work, we implemented an ionization chamber-based absolute dosimetry system for the HCL ocular beamline based on the recommendations given in Report 59 by the International Commission on Radiation Units and Measurements. Comparative measurements revealed that the FC system yields an absorbed dose to water value that is 1.1% higher than was obtained with the IC system. That difference is small compared with the experimental uncertainties and is clinically insignificant. In June of 1998, we adopted the IC-based method as our standard practice for the ocular beam. PMID:12349914

  1. Plasma neutralization models for intense ion beam transport in plasma

    SciTech Connect

    Kaganovich, Igor D.; Startsev, Edward A.; Davidson, Ronald C.; O'Rourke, Sean; Lee, Edward P.

    2003-05-01

    Plasma neutralization of an intense ion pulse is of interest for many applications, including plasma lenses, heavy ion fusion, cosmic ray propagation, etc. An analytical electron fluid model has been developed based on the assumption of long charge bunches (l{sub b} >> r{sub b}). Theoretical predictions are compared with the results of calculations utilizing a particle-in-cell (PIC) code. The cold electron fluid results agree well with the PIC simulations for ion beam propagation through a background plasma. The analytical predictions for the degree of ion beam charge and current neutralization also agree well with the results of the numerical simulations. The model predicts very good charge neutralization (>99%) during quasi-steady-state propagation, provided the beam pulse duration {tau}{sub b} is much longer than the electron plasma period 2{pi}/{omega}{sub p}, where {omega}{sub p} = (4{pi}e{sup 2}n{sub p}/m){sup 1/2} is the electron plasma frequency, and n{sub p} is the background plasma density. In the opposite limit, the beam pulse excites large-amplitude plasma waves. The analytical formulas derived in this paper can provide an important benchmark for numerical codes, and provide scaling relations for different beam and plasma parameters.

  2. Energy gain and spectral tailoring of ion beams using ultra-high intensity laser beams

    NASA Astrophysics Data System (ADS)

    Prasad, Rajendra; Swantusch, Marco; Cerchez, Mirela; Spickermann, Sven; Auorand, Bastian; Wowra, Thomas; Boeker, Juergen; Willi, Oswald

    2015-11-01

    The field of laser driven ion acceleration over the past decade has produced a huge amount of research. Nowadays, several multi-beam facilities with high rep rate system, e.g. ELI, are being developed across the world for different kinds of experiments. The study of interaction dynamics of multiple beams possessing ultra-high intensity and ultra-short pulse duration is of vital importance. Here, we present the first experimental results on ion acceleration using two ultra-high intensity beams. Thanks to the unique capability of Arcturus laser at HHU Düsseldorf, two almost identical, independent beams in laser parameters such as intensity (>1020 W/cm2), pulse duration (30 fs) and contrast (>1010), could be accessed. Both beams are focused onto a 5 μm thin Ti target. While ensuring spatial overlap of the two beams, at relative temporal delay of ~ 50 ps (optimum delay), the proton and carbon ion energies were enhanced by factor of 1.5. Moreover, strong modulation in C4+ions near the high energy cut-off is observed later than the optimum delay for the proton enhancement. This offers controlled tailoring of the spectral content of heavy ions.

  3. Relativistic focusing and ponderomotive channeling of intense laser beams

    PubMed

    Hafizi; Ting; Sprangle; Hubbard

    2000-09-01

    The ponderomotive force associated with an intense laser beam expels electrons radially and can lead to cavitation in plasma. Relativistic effects as well as ponderomotive expulsion of electrons modify the refractive index. An envelope equation for the laser spot size is derived, using the source-dependent expansion method with Laguerre-Gaussian eigenfunctions, and reduced to quadrature. The envelope equation is valid for arbitrary laser intensity within the long pulse, quasistatic approximation and neglects instabilities. Solutions of the envelope equation are discussed in terms of an effective potential for the laser spot size. An analytical expression for the effective potential is given. For laser powers exceeding the critical power for relativistic self-focusing the analysis indicates that a significant contraction of the spot size and a corresponding increase in intensity is possible. PMID:11088939

  4. Relativistic focusing and ponderomotive channeling of intense laser beams

    SciTech Connect

    Hafizi, B.; Ting, A.; Sprangle, P.; Hubbard, R. F.

    2000-09-01

    The ponderomotive force associated with an intense laser beam expels electrons radially and can lead to cavitation in plasma. Relativistic effects as well as ponderomotive expulsion of electrons modify the refractive index. An envelope equation for the laser spot size is derived, using the source-dependent expansion method with Laguerre-Gaussian eigenfunctions, and reduced to quadrature. The envelope equation is valid for arbitrary laser intensity within the long pulse, quasistatic approximation and neglects instabilities. Solutions of the envelope equation are discussed in terms of an effective potential for the laser spot size. An analytical expression for the effective potential is given. For laser powers exceeding the critical power for relativistic self-focusing the analysis indicates that a significant contraction of the spot size and a corresponding increase in intensity is possible. (c) 2000 The American Physical Society.

  5. Optimization of a charge-state analyzer for electron cyclotron resonance ion source beams

    SciTech Connect

    Saminathan, S.; Beijers, J. P. M.; Kremers, H. R.; Mironov, V.; Mulder, J.; Brandenburg, S.

    2012-07-15

    A detailed experimental and simulation study of the extraction of a 24 keV He{sup +} beam from an ECR ion source and the subsequent beam transport through an analyzing magnet is presented. We find that such a slow ion beam is very sensitive to space-charge forces, but also that the neutralization of the beam's space charge by secondary electrons is virtually complete for beam currents up to at least 0.5 mA. The beam emittance directly behind the extraction system is 65 {pi} mm mrad and is determined by the fact that the ion beam is extracted in the strong magnetic fringe field of the ion source. The relatively large emittance of the beam and its non-paraxiality lead, in combination with a relatively small magnet gap, to significant beam losses and a five-fold increase of the effective beam emittance during its transport through the analyzing magnet. The calculated beam profile and phase-space distributions in the image plane of the analyzing magnet agree well with measurements. The kinematic and magnet aberrations have been studied using the calculated second-order transfer map of the analyzing magnet, with which we can reproduce the phase-space distributions of the ion beam behind the analyzing magnet. Using the transfer map and trajectory calculations we have worked out an aberration compensation scheme based on the addition of compensating hexapole components to the main dipole field by modifying the shape of the poles. The simulations predict that by compensating the kinematic and geometric aberrations in this way and enlarging the pole gap the overall beam transport efficiency can be increased from 16% to 45%.

  6. Optimization of a charge-state analyzer for electron cyclotron resonance ion source beams.

    PubMed

    Saminathan, S; Beijers, J P M; Kremers, H R; Mironov, V; Mulder, J; Brandenburg, S

    2012-07-01

    A detailed experimental and simulation study of the extraction of a 24 keV He(+) beam from an ECR ion source and the subsequent beam transport through an analyzing magnet is presented. We find that such a slow ion beam is very sensitive to space-charge forces, but also that the neutralization of the beam's space charge by secondary electrons is virtually complete for beam currents up to at least 0.5 mA. The beam emittance directly behind the extraction system is 65 π mm mrad and is determined by the fact that the ion beam is extracted in the strong magnetic fringe field of the ion source. The relatively large emittance of the beam and its non-paraxiality lead, in combination with a relatively small magnet gap, to significant beam losses and a five-fold increase of the effective beam emittance during its transport through the analyzing magnet. The calculated beam profile and phase-space distributions in the image plane of the analyzing magnet agree well with measurements. The kinematic and magnet aberrations have been studied using the calculated second-order transfer map of the analyzing magnet, with which we can reproduce the phase-space distributions of the ion beam behind the analyzing magnet. Using the transfer map and trajectory calculations we have worked out an aberration compensation scheme based on the addition of compensating hexapole components to the main dipole field by modifying the shape of the poles. The simulations predict that by compensating the kinematic and geometric aberrations in this way and enlarging the pole gap the overall beam transport efficiency can be increased from 16% to 45%. PMID:22852683

  7. SIMULATION OF INTENSE BEAMS FOR HEAVY ION FUSION

    SciTech Connect

    Friedman, A

    2004-06-10

    Computer simulations of intense ion beams play a key role in the Heavy Ion Fusion research program. Along with analytic theory, they are used to develop future experiments, guide ongoing experiments, and aid in the analysis and interpretation of experimental results. They also afford access to regimes not yet accessible in the experimental program. The U.S. Heavy Ion Fusion Virtual National Laboratory and its collaborators have developed state-of-the art computational tools, related both to codes used for stationary plasmas and to codes used for traditional accelerator applications, but necessarily differing from each in important respects. These tools model beams in varying levels of detail and at widely varying computational cost. They include moment models (envelope equations and fluid descriptions), particle-in-cell methods (electrostatic and electromagnetic), nonlinear-perturbative descriptions (''{delta}f''), and continuum Vlasov methods. Increasingly, it is becoming clear that it is necessary to simulate not just the beams themselves, but also the environment in which they exist, be it an intentionally-created plasma or an unwanted cloud of electrons and gas. In this paper, examples of the application of simulation tools to intense ion beam physics are presented, including support of present-day experiments, fundamental beam physics studies, and the development of future experiments. Throughout, new computational models are described and their utility explained. These include Mesh Refinement (and its dynamic variant, Adaptive Mesh Refinement); improved electron cloud and gas models, and an electron advance scheme that allows use of larger time steps; and moving-mesh and adaptive-mesh Vlasov methods.

  8. Electrostatic ion cyclotron waves in a plasma with an ion beam and counterstreaming bulk electrons - Waves in the zero-frequency band

    NASA Astrophysics Data System (ADS)

    Singh, N.; Conrad, J. R.; Schunk, R. W.

    1985-12-01

    A common feature of the auroral plasma in the region above field-aligned (parallel) potential drops are electrostatic hydrogen cyclotron (EHC) waves. The present paper has the objective to show that wave excitation in the zero-frequency band can occur when the ion beams and the current-carrying bulk electrons counterstream. The instability mechanism involves the Landau interaction of the slow (negative energy) ion-beam-cyclotron waves with the drifting electrons and also with the target (background) ions. Only the latter resonant interaction between the beam and the target ions was considered by Okuda and Nishikawa (1984). In this study, it is shown that an electron drift makes an additional unstable contribution to the waves in the zero-frequency band, including those discussed by Okuda and Nishikawa.

  9. Beams for the Intensity Frontier of Particle Physics

    NASA Astrophysics Data System (ADS)

    Tschirhart, Robert S.

    2014-02-01

    Advances in high intensity beams have driven particle physics forward since the inception of the field. State-of-the-art and next generation high intensity beams will drive experiments searching for ultrarare processes sensitive through quantum corrections to new particle states far beyond the reach of direct production in foreseeable beam colliders. The recent discovery of the ultrarare B meson decay Bs → μμ, with a branching fraction of 3 × 10-9 for example, has set stringent limits on new physics within direct reach of the Large Hadron Collider. Today, even in the context of the Higgs boson discovery, observation of finite neutrino masses is the only laboratory evidence of physics beyond the Standard Model of particle physics. The tiny mass scale of neutrinos may foretell and one day expose physics that connects quarks and leptons together at the "grand unification" scale and may be the portal through which our world came to the matter-dominated state so different from conditions we expect in the early universe. Here we describe next generation neutrino and rare processes experiments that will deeply probe these and other questions central to the field of particle physics.

  10. Modeling nitrogen plasmas produced by intense electron beams

    NASA Astrophysics Data System (ADS)

    Angus, J. R.; Mosher, D.; Swanekamp, S. B.; Ottinger, P. F.; Schumer, J. W.; Hinshelwood, D. D.

    2016-05-01

    A new gas-chemistry model is presented to treat the breakdown of a nitrogen gas with pressures on the order of 1 Torr from intense electron beams with current densities on the order of 10 kA/cm2 and pulse durations on the order of 100 ns. For these parameter regimes, the gas transitions from a weakly ionized molecular state to a strongly ionized atomic state on the time scale of the beam pulse. The model is coupled to a 0D-circuit model using the rigid-beam approximation that can be driven by specifying the time and spatial profiles of the beam pulse. Simulation results are in good agreement with experimental measurements of the line-integrated electron density from experiments done using the Gamble II generator at the Naval Research Laboratory. It is found that the species are mostly in the ground and metastable states during the atomic phase, but that ionization proceeds predominantly through thermal ionization of optically allowed states with excitation energies close to the ionization limit.

  11. Bipolar pulse generator for intense pulsed ion beam accelerator

    SciTech Connect

    Ito, H.; Igawa, K.; Kitamura, I.; Masugata, K.

    2007-01-15

    A new type of pulsed ion beam accelerator named ''bipolar pulse accelerator'' (BPA) has been proposed in order to improve the purity of intense pulsed ion beams. To confirm the principle of the BPA, we developed a bipolar pulse generator for the bipolar pulse experiment, which consists of a Marx generator and a pulse forming line (PFL) with a rail gap switch on its end. In this article, we report the first experimental result of the bipolar pulse and evaluate the electrical characteristics of the bipolar pulse generator. When the bipolar pulse generator was operated at 70% of the full charge condition of the PFL, the bipolar pulse with the first (-138 kV, 72 ns) and the second pulse (+130 kV, 70 ns) was successfully obtained. The evaluation of the electrical characteristics indicates that the developed generator can produce the bipolar pulse with fast rise time and sharp reversing time.

  12. Bipolar pulse generator for intense pulsed ion beam accelerator.

    PubMed

    Ito, H; Igawa, K; Kitamura, I; Masugata, K

    2007-01-01

    A new type of pulsed ion beam accelerator named "bipolar pulse accelerator" (BPA) has been proposed in order to improve the purity of intense pulsed ion beams. To confirm the principle of the BPA, we developed a bipolar pulse generator for the bipolar pulse experiment, which consists of a Marx generator and a pulse forming line (PFL) with a rail gap switch on its end. In this article, we report the first experimental result of the bipolar pulse and evaluate the electrical characteristics of the bipolar pulse generator. When the bipolar pulse generator was operated at 70% of the full charge condition of the PFL, the bipolar pulse with the first (-138 kV, 72 ns) and the second pulse (+130 kV, 70 ns) was successfully obtained. The evaluation of the electrical characteristics indicates that the developed generator can produce the bipolar pulse with fast rise time and sharp reversing time. PMID:17503918

  13. INERTIAL FUSION DRIVEN BY INTENSE HEAVY-ION BEAMS

    SciTech Connect

    Sharp, W. M.; Friedman, A.; Grote, D. P.; Barnard, J. J.; Cohen, R. H.; Dorf, M. A.; Lund, S. M.; Perkins, L. J.; Terry, M. R.; Logan, B. G.; Bieniosek, F. M.; Faltens, A.; Henestroza, E.; Jung, J. Y.; Kwan, J. W.; Lee, E. P.; Lidia, S. M.; Ni, P. A.; Reginato, L. L.; Roy, P. K.; Seidl, P. A.; Takakuwa, J. H.; Vay, J.-L.; Waldron, W. L.; Davidson, R. C.; Gilson, E. P.; Kaganovich, I. D.; Qin, H.; Startsev, E.; Haber, I.; Kishek, R. A.; Koniges, A. E.

    2011-03-31

    Intense heavy-ion beams have long been considered a promising driver option for inertial-fusion energy production. This paper briefly compares inertial confinement fusion (ICF) to the more-familiar magnetic-confinement approach and presents some advantages of using beams of heavy ions to drive ICF instead of lasers. Key design choices in heavy-ion fusion (HIF) facilities are discussed, particularly the type of accelerator. We then review experiments carried out at Lawrence Berkeley National Laboratory (LBNL) over the past thirty years to understand various aspects of HIF driver physics. A brief review follows of present HIF research in the US and abroad, focusing on a new facility, NDCX-II, being built at LBNL to study the physics of warm dense matter heated by ions, as well as aspects of HIF target physics. Future research directions are briefly summarized.

  14. Design Aspects of Focal Beams From High-Intensity Arrays

    PubMed Central

    Stephens, Douglas N.; Kruse, Dustin E.; Qin, Shengping; Ferrara, Katherine W.

    2011-01-01

    As the applications of ultrasonic thermal therapies expand, the design of the high-intensity array must address both the energy delivery of the main beam and the character and relevance of off-target beam energy. We simulate the acoustic field performance of a selected set of circular arrays organized by array format, including flat versus curved arrays, periodic versus random arrays, and center void diameter variations. Performance metrics are based on the −3-dB focal main lobe (FML) positioning range, axial grating lobe (AGL) temperatures, and side lobe levels. Using finite-element analysis, we evaluate the relative heating of the FML and the AGLs. All arrays have a maximum diameter of 100λ, with element count ranging from 64 to 1024 and continuous wave frequency of 1.5 MHz. First, we show that a 50% spherical annulus produces focus beam side lobes which decay as a function of lateral distance at nearly 87% of the exponential rate of a full aperture. Second, for the arrays studied, the efficiency of power delivery over the −3-dB focus positioning range for spherical arrays is at least 2-fold greater than for flat arrays; the 256-element case shows a 5-fold advantage for the spherical array. Third, AGL heating can be significant as the focal target is moved to its distal half-intensity depth from the natural focus. Increasing the element count of a randomized array to 256 elements decreases the AGL-to-FML heating ratio to 0.12 at the distal half-intensity depth. Further increases in element count yield modest improvements. A 49% improvement in the AGL-to-peak heating ratio is predicted by using the Sumanaweera spiral element pattern with randomization. PMID:21859578

  15. A high intensity positron beam at the Brookhaven reactor

    SciTech Connect

    Weber, M.; Lynn, K.G.; Roellig, L.O.; Mills, A.P. Jr.; Moodenbaugh, A.R.

    1987-01-01

    We describe a high intensity, low energy positron beam utilizing high specific activity /sup 64/Cu sources (870 Ci/g) produced in a reactor with high thermal neutron flux. Fast-to-slow moderation can be performed in a self moderation mode or with a transmission moderator. Slow positron rates up to 1.6 x 10/sup 8/ e/sup +//s with a half life of 12.8 h are calculated. Up to 1.0 x 10/sup 8/ e/sup +//s have been observed. New developments including a Ne moderator and an on-line isotope separation process are discussed. 21 refs., 9 figs.

  16. Anomalous behavior of LEED beam intensity during annealing

    NASA Astrophysics Data System (ADS)

    Fu, Tsu-Yi; Liu, T. F.; Su, C. W.; Shern, C. S.; Chen, R. H.

    2000-10-01

    Low-energy electron diffraction was used to study the annealing effects of 1 ML Ag on the ultra-thin-film Co/Pt (111). The behavior of the specular beam intensity versus temperature is anomalous. Besides the normal Debye-Waller effect, a bend occurs at 550 K, and a dramatic increase occurs at a higher temperature. A corresponding study by Auger electron spectroscopy and ultraviolet photoelectron spectroscopy indicates that the bend results from the Co inter-diffusion. The anomalous increase indicates that a more stable state forms at a higher temperature. The Co coverage plays an important role in determining the turning temperature. Possible mechanisms are discussed.

  17. Profiles of ion beams and plasma parameters on a multi-frequencies microwaves large bore electron cyclotron resonance ion source with permanent magnets

    SciTech Connect

    Kato, Yushi; Sakamoto, Naoki; Kiriyama, Ryutaro; Takenaka, Tomoya; Kurisu, Yosuke; Nozaki, Dai; Sato, Fuminobu; Iida, Toshiyuki

    2012-02-15

    In order to contribute to various applications of plasma and beams based on an electron cyclotron resonance, a new concept on magnetic field with all magnets on plasma production and confinement has been proposed with enhanced efficiency for broad and dense ion beam. The magnetic field configuration consists of a pair of comb-shaped magnet surrounding plasma chamber cylindrically. Resonance zones corresponding for 2.45 GHz and 11-13 GHz frequencies are positioned at spatially different positions. We launch simultaneously multiplex frequencies microwaves operated individually, try to control profiles of the plasma parameters and the extracted ion beams, and to measure them in detail.

  18. Computer modeling of a compact isochronous cyclotron

    NASA Astrophysics Data System (ADS)

    Smirnov, V. L.

    2015-11-01

    The computer modeling methods of a compact isochronous cyclotron are described. The main stages of analysis of accelerator facilities systems are considered. The described methods are based on theoretical fundamentals of cyclotron physics and mention highlights of creation of the physical project of a compact cyclotron. The main attention is paid to the analysis of the beam dynamics, formation of a magnetic field, stability of the movement, and a realistic assessment of intensity of the generated bunch of particles. In the article, the stages of development of the accelerator computer model, analytical ways of assessment of the accelerator parameters, and the basic technique of the numerical analysis of dynamics of the particles are described.

  19. Beam Phase Space of an Intense Ion Beam in a Neutralizing Plasma

    NASA Astrophysics Data System (ADS)

    Seidl, Peter A.; Bazouin, Guillaume; Beneytout, Alice; Lidia, Steven M.; Vay, Jean-Luc; Grote, David P.

    2011-10-01

    The Neutralized Drift Compression Experiment (NDCX-I) generates high intensity ion beams to explore warm dense matter physics. Transverse final focusing is accomplished with an 8-Tesla, 10-cm long pulsed solenoid magnet combined with a background neutralizing plasma to effectively cancel the space charge field of the ion beam. We report on phase space measurements of the beam before the neutralization channel and of the focused ion beam at the target plane. These are compared to WARP particle-in-cell simulations of the ion beam propagation through the focusing system and neutralizing plasma. Due to the orientation of the plasma sources with respect to the focusing magnet, the plasma distribution within the final focusing lens is strongly affected by the magnetic field, an effect which can influence the peak intensity at the target and which is included in the model of the experiment. Work performed under auspices of U.S. DoE by LLNL, LBNL under Contracts DE-AC52-07NA27344, DE-AC02-05CH1123.

  20. Plasma opening switch for long-pulse intense ion beam

    SciTech Connect

    Davis, H.A.; Mason, R.J.; Bartsch, R.R.; Greenly, J.B.; Rej, D.J.

    1992-01-01

    A Plasma Opening Switch (POS) is being developed at Los Alamos, as part of an intense ion beam experiment with special application to materials processing. The switch must conduct up to 100 kA for 600 ns, and open quickly to avoid premature gap closure in the ion beam diode load. Power multiplication is not a necessity, but prepulse suppression is. A positive central polarity is desirable, since with it an ion beam can be conveniently launched beyond the switch from the central anode toward a negatively charged target. Thus, otherwise by virtue of traditional scaling rules, a POS was designed with a 1.25 cm radius inner anode, and a 4.75 cm radius outer cathode. This has been constructed, and subjected to circuit, and simulational analysis. The computations are being performed with the 2D ANTHEM implicit code. Preliminary results show a marked difference in switching dynamics, when the central positive polarity is used in place of the more conventional opposite choice. Opening goes by the fast development of a central anode magnetic layer, rather than by the more conventional slow evolution of a cathode gap. With the central anode, higher fill densities are needed to achieve desired conduction times. This has suggested switch design improvements, which are discussed.

  1. Plasma opening switch for long-pulse intense ion beam

    SciTech Connect

    Davis, H.A.; Mason, R.J.; Bartsch, R.R.; Greenly, J.B.; Rej, D.J.

    1992-08-01

    A Plasma Opening Switch (POS) is being developed at Los Alamos, as part of an intense ion beam experiment with special application to materials processing. The switch must conduct up to 100 kA for 600 ns, and open quickly to avoid premature gap closure in the ion beam diode load. Power multiplication is not a necessity, but prepulse suppression is. A positive central polarity is desirable, since with it an ion beam can be conveniently launched beyond the switch from the central anode toward a negatively charged target. Thus, otherwise by virtue of traditional scaling rules, a POS was designed with a 1.25 cm radius inner anode, and a 4.75 cm radius outer cathode. This has been constructed, and subjected to circuit, and simulational analysis. The computations are being performed with the 2D ANTHEM implicit code. Preliminary results show a marked difference in switching dynamics, when the central positive polarity is used in place of the more conventional opposite choice. Opening goes by the fast development of a central anode magnetic layer, rather than by the more conventional slow evolution of a cathode gap. With the central anode, higher fill densities are needed to achieve desired conduction times. This has suggested switch design improvements, which are discussed.

  2. Production of high intensity Beta beams at the ISOLDE facility

    NASA Astrophysics Data System (ADS)

    Hodák, Rastislav; Stora, Thierry; Mendonça, Tania M.

    2011-12-01

    We discuss a design study devoted to a construction of the Beta beams facility at CERN, a next generation European facility aiming for a production of pure and collimated ultra-relativistic beam of electron (anti)neutrinos with help of accelerated β-decaying radioactive ions circulating in a storage decay ring. This high intense source of (anti)neutrinos directed towards a remote underground neutrino detector will allow to measure neutrino oscillations with high accuracy offering a unique chance for establishing a value of the β13 mixing angle and CP violating phase. Recently, a significant progress have been achieved on the conceptual design of high power targets required for a production and an extraction of two baseline isotopes, 6He and 18Ne, at the unexampled rate of several 1013 ions/s. There is a possibility to produce these isotopes using the so-called Isotope Separation On Line (ISOL) method at the ISOLDE facility (CERN). The 6He production is realized by taking advantage of the 9Be(n,α)6He reaction and with help of spallation neutrons and porous BeO target material. The production of 18Ne through the 19F(p,2n)18Ne reaction at required intensities is even more challenging. Currently, a molten salt (NaF) loop target is proposed for a production of high rate of 18Ne required for the Beta beams project. The progress on the design study associated with new data and plans for future is briefly presented.

  3. K-130 Cyclotron vacuum system

    NASA Astrophysics Data System (ADS)

    Yadav, R. C.; Bhattacharya, S.; Bhole, R. B.; Roy, Anindya; Pal, Sarbajit; Mallik, C.; Bhandari, R. K.

    2012-11-01

    The vacuum system for K-130 cyclotron has been operational since 1977. It consists of two sub-systems, main vacuum system and beam line vacuum system. The main vacuum system is designed to achieve and maintain vacuum of about 1 × 10-6 mbar inside the 23 m3 volume of acceleration chamber comprising the Resonator tank and the Dee tank. The beam line vacuum system is required for transporting the extracted beam with minimum loss. These vacuum systems consist of diffusion pumps backed by mechanical pumps like roots and rotary pumps. The large vacuum pumps and valves of the cyclotron vacuum system were operational for more than twenty five years. In recent times, problems of frequent failures and maintenance were occurring due to aging and lack of appropriate spares. Hence, modernisation of the vacuum systems was taken up in order to ensure a stable high voltage for radio frequency system and the extraction system. This is required for efficient acceleration and transportation of high intensity ion beam. The vacuum systems have been upgraded by replacing several pumps, valves, gauges and freon units. The relay based control system for main vacuum system has also been replaced by PLC based state of the art control system. The upgraded control system enables inclusion of additional operational logics and safety interlocks into the system. The paper presents the details of the vacuum system and describes the modifications carried out for improving the performance and reliability of the vacuum system.

  4. Neutron beam characterization at the Intense Pulsed Neutron Source.

    SciTech Connect

    Iverson, E. B.

    1998-05-18

    The Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory is a spallation neutron source dedicated to materials research. Its three cryogenic methane moderators provide twelve neutron beams to fourteen neutron scattering instruments and test facilities. The moderators at IPNS are of cryogenic methane (CH{sub 4}); one of liquid methane at 100 K, and two of solid methane at 30 K. These moderators produce intense beams of both cold and thermal neutrons. The moderators are each of a different physical configuration in order to tailor their performance for the instruments and facilities that operate on the neutron beams. As part of the ongoing operation of IPNS, as well as new enhancements to the target, moderator, and reflector systems, we have performed experiments characterizing the energy and time distribution of neutrons in the various beams. These measurements provide absolutely normalized energy spectra using foil activation techniques joined with time-of-flight measurements, and energy-dependent time distributions using a time-focused crystal analyzer. The IPNS accelerator system delivers 14 {micro}A of 450 MeV protons, in 100 ns pulses at 30 Hz, to a target composed of water-cooled depleted uranium disks. The solid methane ''H'' moderator is 100 by 100 by 45 mm in size, centerline poisoned with 0.25 mg/mm{sup 2} gadolinium, and decoupled from the graphite reflector with 0.5 mm of cadmium. The liquid methane ''F'' moderator, which is viewed from both faces, is also 100 by 100 by 45 mm in size, gadolinium poisoned 16 mm below each of the two viewed surfaces, and decoupled from the graphite reflector with cadmium. The solid methane ''C'' moderator has a re-entrant ''grooved'' geometry. The moderator is 100 by 100 by 80 mm overall, with 40 mm deep 12 mm wide horizontal grooves in the viewed surface. These grooves cover 50% of the viewed surface area. The ''C'' moderator is unpoisoned, but is decoupled from the graphite reflector with 0.5 mm of cadmium.

  5. Electron Production and Collective Field Generation in Intense Particle Beams

    SciTech Connect

    Molvik, A W; Vay, J; Cohen, R; Friedman, A; Lee, E; Verboncoeur, J; Covo, M K

    2006-02-09

    Electron cloud effects (ECEs) are increasingly recognized as important, but incompletely understood, dynamical phenomena, which can severely limit the performance of present electron colliders, the next generation of high-intensity rings, such as PEP-II upgrade, LHC, and the SNS, the SIS 100/200, or future high-intensity heavy ion accelerators such as envisioned in Heavy Ion Inertial Fusion (HIF). Deleterious effects include ion-electron instabilities, emittance growth, particle loss, increase in vacuum pressure, added heat load at the vacuum chamber walls, and interference with certain beam diagnostics. Extrapolation of present experience to significantly higher beam intensities is uncertain given the present level of understanding. With coordinated LDRD projects at LLNL and LBNL, we undertook a comprehensive R&D program including experiments, theory and simulations to better understand the phenomena, establish the essential parameters, and develop mitigating mechanisms. This LDRD project laid the essential groundwork for such a program. We developed insights into the essential processes, modeled the relevant physics, and implemented these models in computational production tools that can be used for self-consistent study of the effect on ion beams. We validated the models and tools through comparison with experimental data, including data from new diagnostics that we developed as part of this work and validated on the High-Current Experiment (HCX) at LBNL. We applied these models to High-Energy Physics (HEP) and other advanced accelerators. This project was highly successful, as evidenced by the two paragraphs above, and six paragraphs following that are taken from our 2003 proposal with minor editing that mostly consisted of changing the tense. Further benchmarks of outstanding performance are: we had 13 publications with 8 of them in refereed journals, our work was recognized by the accelerator and plasma physics communities by 8 invited papers and we have 5

  6. Accessing defect dynamics using intense, nanosecond pulsed ion beams

    SciTech Connect

    Persaud, A.; Barnard, J. J.; Guo, H.; Hosemann, P.; Lidia, S.; Minor, A. M.; Seidl, P. A.; Schenkel, T.

    2015-06-18

    Gaining in-situ access to relaxation dynamics of radiation induced defects will lead to a better understanding of materials and is important for the verification of theoretical models and simulations. We show preliminary results from experiments at the new Neutralized Drift Compression Experiment (NDCX-II) at Lawrence Berkeley National Laboratory that will enable in-situ access to defect dynamics through pump-probe experiments. Here, the unique capabilities of the NDCX-II accelerator to generate intense, nanosecond pulsed ion beams are utilized. Preliminary data of channeling experiments using lithium and potassium ions and silicon membranes are shown. We compare these data to simulation results using Crystal Trim. Furthermore, we discuss the improvements to the accelerator to higher performance levels and the new diagnostics tools that are being incorporated.

  7. Accessing defect dynamics using intense, nanosecond pulsed ion beams

    DOE PAGESBeta

    Persaud, A.; Barnard, J. J.; Guo, H.; Hosemann, P.; Lidia, S.; Minor, A. M.; Seidl, P. A.; Schenkel, T.

    2015-06-18

    Gaining in-situ access to relaxation dynamics of radiation induced defects will lead to a better understanding of materials and is important for the verification of theoretical models and simulations. We show preliminary results from experiments at the new Neutralized Drift Compression Experiment (NDCX-II) at Lawrence Berkeley National Laboratory that will enable in-situ access to defect dynamics through pump-probe experiments. Here, the unique capabilities of the NDCX-II accelerator to generate intense, nanosecond pulsed ion beams are utilized. Preliminary data of channeling experiments using lithium and potassium ions and silicon membranes are shown. We compare these data to simulation results using Crystalmore » Trim. Furthermore, we discuss the improvements to the accelerator to higher performance levels and the new diagnostics tools that are being incorporated.« less

  8. Infrared imaging diagnostics for intense pulsed electron beam

    SciTech Connect

    Yu, Xiao; Shen, Jie; Liu, Wenbin; Zhong, Haowen; Zhang, Jie; Zhang, Gaolong; Le, Xiaoyun; Qu, Miao; Yan, Sha

    2015-08-15

    Infrared imaging diagnostic method for two-dimensional calorimetric diagnostics has been developed for intense pulsed electron beam (IPEB). By using a 100-μm-thick tungsten film as the infrared heat sink for IPEB, the emitting uniformity of the electron source can be analyzed to evaluate the efficiency and stability of the diode system. Two-dimensional axisymmetric finite element method heat transfer simulation, combined with Monte Carlo calculation, was performed for error estimation and optimization of the method. The test of the method was finished with IPEB generated by explosive emission electron diode with pulse duration (FWHM) of 80 ns, electron energy up to 450 keV, and a total beam current of over 1 kA. The results showed that it is possible to measure the cross-sectional energy density distribution of IPEB with energy sensitivity of 0.1 J/cm{sup 2} and spatial resolution of 1 mm. The technical details, such as irradiation protection of bremsstrahlung γ photons and the functional extensibility of the method were discussed in this work.

  9. The stress intensity factor for the double cantilever beam

    NASA Technical Reports Server (NTRS)

    Fichter, W. B.

    1983-01-01

    Fourier transforms and the Wiener-Hopf technique are used in conjunction with plane elastostatics to examine the singular crack tip stress field in the double cantilever beam (DCB) specimen. In place of the Dirac delta function, a family of functions which duplicates the important features of the concentrated forces without introducing unmanageable mathematical complexities is used as a loading function. With terms of order h-squared/a-squared retained in the series expansion, the dimensionless stress intensity factor is found to be K (h to the 1/2)/P = 12 to the 1/2 (a/h + 0.6728 + 0.0377 h-squared/a-squared), in which P is the magnitude of the concentrated forces per unit thickness, a is the distance from the crack tip to the points of load application, and h is the height of each cantilever beam. The result is similar to that obtained by Gross and Srawley by fitting a line to discrete results from their boundary collocation analysis.

  10. Three-Dimensional Perturbative Particle Simulation of Intense Ion Beams

    NASA Astrophysics Data System (ADS)

    Lee, W. Wei-Li; Stoltz, Peter H.; Davidson, Ronald C.; Qin, Hong

    1998-11-01

    A three-dimensional nonlinear perturbative (δ f) particle simulation scheme is under developement for studying the stability and transport properties of an intense ion beam propagating through background electrons and a periodic focusing lattice,(Q. Qian, W. Lee, and R. C. Davidson, Phys. Plasmas 4), 1915 (1997).^,(P. H. Stoltz, W. W. Lee, R. C. Davidson, this conference.) in which the distribution function is split into equilibrium and perturbed parts. To further facilitate the simulations, a mode expansion scheme (C. Z. Cheng and H. Okuda, J. Comp. Phys. 25), 133 (1977). for the perturbative scheme has been developed, in which only a few long wavelength modes along the direction of propagation are kept. The code will be useful for many applications in beam physics and is an intermediate step toward a fully three-dimensional multi-species code. The algorithm and its applications to the electron-proton instability (R. C. Davidson, P. H. Stoltz, W. W. Lee and T.-S. Wang, this conference.) in proton linacs and storage rings will be reported.

  11. Ultraviolet Lasing in Air Caused by Intense Relativistic Electron Beams.

    NASA Astrophysics Data System (ADS)

    Atchison, Walter Louis

    As an intense relativistic electron beam (REB) passes through the atmosphere, it interacts heavily with the N_2 present and produces a large population of excited molecules. Calculations presented indicate that the excitation rates and the Franck-Condon factors combine to cause a population inversion for selected states in the triplet manifold of N_2. This inversion and the geometry of the propagating beam causes amplified spontaneous emission which is greatest in the axially direction of REB propagation. The ultraviolet (UV) yields from the N_2 triplet states caused by a REB have been calculated for the pressure range 0.5 to 1000 torr. As the REB and UV pulse propagate together at or near the speed of light, an interesting condition results. Normal geometric and temporal considerations which affect typical discharge lasers do not, in this case, limit the pulse width and total amplitude of the UV pulse. Calculations predict significant yields at pressures above 100 torr. The yield in this region is aided by the electron cascade caused by the primary electrons of the REB. Measurements along the propagation axis using the LLNL Experimental Test Accelerator (ETA), while insufficient to verify the pressure dependence, indicate enhancement of 3371 A emissions by at least a factor of 1000 over the level predicted by spontaneous emission alone.

  12. Infrared imaging diagnostics for intense pulsed electron beam.

    PubMed

    Yu, Xiao; Shen, Jie; Qu, Miao; Liu, Wenbin; Zhong, Haowen; Zhang, Jie; Yan, Sha; Zhang, Gaolong; Le, Xiaoyun

    2015-08-01

    Infrared imaging diagnostic method for two-dimensional calorimetric diagnostics has been developed for intense pulsed electron beam (IPEB). By using a 100-μm-thick tungsten film as the infrared heat sink for IPEB, the emitting uniformity of the electron source can be analyzed to evaluate the efficiency and stability of the diode system. Two-dimensional axisymmetric finite element method heat transfer simulation, combined with Monte Carlo calculation, was performed for error estimation and optimization of the method. The test of the method was finished with IPEB generated by explosive emission electron diode with pulse duration (FWHM) of 80 ns, electron energy up to 450 keV, and a total beam current of over 1 kA. The results showed that it is possible to measure the cross-sectional energy density distribution of IPEB with energy sensitivity of 0.1 J/cm(2) and spatial resolution of 1 mm. The technical details, such as irradiation protection of bremsstrahlung γ photons and the functional extensibility of the method were discussed in this work. PMID:26329179

  13. A sub-nanosecond rise time intense electron beam source

    NASA Astrophysics Data System (ADS)

    Kumar, R.; Chandra, R.; Mitra, S.; Beg, M. D.; Sharma, D. K.; Sharma, A.; Mittal, K. C.

    2014-04-01

    This paper presents the design and development of a 75 kV, 55 A, 2 nanosecond duration, <= 850 ps rise time, single shot, intense ( >= 100 A/cm2) electron beam source and also the measurement technique adopted in sub-nanosecond regime. A 200 kV (nanosecond pulse) coaxial pulse forming line (PFL) based pulser is designed to drive a cold cathode explosive emission electron gun. The electron gun diode consists with a planer graphite cathode, which has the emission area of 8 mm diameter and a SS 304L anode mesh. Vacuum is achieved of the order of 3.5e-5 mbar by using a diffusion pump, backed by rotary pump. At the diagnostic side for diode voltage measurement a fast response copper sulphate aqueous solution resistive voltage divider is designed and implemented. For the beam current diagnostic a graphite Faraday cup is designed with taking care of response time in GHz (1.0-3.0 GHz) regime. The circuit diagram, voltage and current waveforms and the experimental setup is presented.

  14. STEREO and Wind Observations of Intense Cyclotron Harmonic Waves at the Earth's Bow Shock and Inside the Magnetosheath

    NASA Technical Reports Server (NTRS)

    Breneman, A. W.; Cattell, C.

    2013-01-01

    We present the first observations of electron cyclotron harmonic waves at the Earth's bow shock from STEREO and Wind burst waveform captures. These waves are observed at magnetic field gradients at a variety of shock geometries ranging from quasi-parallel to nearly perpendicular along with whistler mode waves, ion acoustic waves, and electrostatic solitary waves. Large amplitude cyclotron harmonic waveforms are also observed in the magnetosheath in association with magnetic field gradients convected past the bow shock. Amplitudes of the cyclotron harmonic waves range from a few tens to more than 500 millivolts/meter peak-peak. A comparison between the short (15 meters) and long (100 meters) Wind spin plane antennas shows a similar response at low harmonics and a stronger response on the short antenna at higher harmonics. This indicates that wavelengths are not significantly larger than 100 meters, consistent with the electron cyclotron radius. Waveforms are broadband and polarizations are distinctively comma-shaped with significant power both perpendicular and parallel to the magnetic field. Harmonics tend to be more prominent in the perpendicular directions. These observations indicate that the waves consist of a combination of perpendicular Bernstein waves and field-aligned waves without harmonics. A likely source is the electron cyclotron drift instability which is a coupling between Bernstein and ion acoustic waves. These waves are the most common type of high-frequency wave seen by STEREO during bow shock crossings and magnetosheath traversals and our observations suggest that they are an important component of the high-frequency turbulent spectrum in these regions.

  15. Varying stopping and self-focusing of intense proton beams as they heat solid density matter

    NASA Astrophysics Data System (ADS)

    Kim, J.; McGuffey, C.; Qiao, B.; Wei, M. S.; Grabowski, P. E.; Beg, F. N.

    2016-04-01

    Transport of intense proton beams in solid-density matter is numerically investigated using an implicit hybrid particle-in-cell code. Both collective effects and stopping for individual beam particles are included through the electromagnetic fields solver and stopping power calculations utilizing the varying local target conditions, allowing self-consistent transport studies. Two target heating mechanisms, the beam energy deposition and Ohmic heating driven by the return current, are compared. The dependences of proton beam transport in solid targets on the beam parameters are systematically analyzed, i.e., simulations with various beam intensities, pulse durations, kinetic energies, and energy distributions are compared. The proton beam deposition profile and ultimate target temperature show strong dependence on intensity and pulse duration. A strong magnetic field is generated from a proton beam with high density and tight beam radius, resulting in focusing of the beam and localized heating of the target up to hundreds of eV.

  16. Images of Complex Interactions of an Intense Ion Beam with Plasma Electrons

    SciTech Connect

    Igor D. Kaganovich; Edward Startsev; Ronald C. Davidson

    2004-08-03

    Ion beam propagation in a background plasma is an important scientific issue for many practical applications. The process of ion beam charge and current neutralization is complex because plasma electrons move in strong electric and magnetic fields of the beam. Computer simulation images of plasma interaction with an intense ion beam pulse are presented.

  17. Nondestructive synchronous beam current monitor

    SciTech Connect

    Covo, Michel Kireeff

    2014-12-15

    A fast current transformer is mounted after the deflectors of the Berkeley 88-Inch Cyclotron. The measured signal is amplified and connected to the input of a lock-in amplifier. The lock-in amplifier performs a synchronous detection of the signal at the cyclotron second harmonic frequency. The magnitude of the signal detected is calibrated against a Faraday cup and corresponds to the beam intensity. It has exceptional resolution, long term stability, and can measure the beam current leaving the cyclotron as low as 1 nA.

  18. Dosimetry in radiobiological studies with the heavy ion beam of the Warsaw cyclotron

    NASA Astrophysics Data System (ADS)

    Kaźmierczak, U.; Banaś, D.; Braziewicz, J.; Czub, J.; Jaskóła, M.; Korman, A.; Kruszewski, M.; Lankoff, A.; Lisowska, H.; Malinowska, A.; Stępkowski, T.; Szefliński, Z.; Wojewódzka, M.

    2015-12-01

    The aim of this study was to verify various dosimetry methods in the irradiation of biological materials with a 12C ion beam at the Heavy Ion Laboratory of the University of Warsaw. To this end the number of ions hitting the cell nucleus, calculated on the basis of the Si-detector system used in the set-up, was compared with the number of ion tracks counted in irradiated Solid State Nuclear Track Detectors and with the number of ion tracks detected in irradiated Chinese Hamster Ovary cells processed for the γ-H2AX assay. Tests results were self-consistent and confirmed that the system serves its dosimetric purpose.

  19. Numerical investigation of auroral cyclotron maser processes

    SciTech Connect

    Speirs, D. C.; Ronald, K.; McConville, S. L.; Gillespie, K. M.; Phelps, A. D. R.; Cross, A. W.; Robertson, C. W.; Whyte, C. G.; He, W.; Bingham, R.; Vorgul, I.; Cairns, R. A.; Kellett, B. J.

    2010-05-15

    When a mainly rectilinear electron beam is subject to significant magnetic compression, conservation of magnetic moment results in the formation of a horseshoe shaped velocity distribution. It has been shown that such a distribution is unstable to cyclotron emission and may be responsible for the generation of auroral kilometric radiation--an intense rf emission sourced at high altitudes in the terrestrial auroral magnetosphere. Particle-in-cell code simulations have been undertaken to investigate the dynamics of the cyclotron emission process in the absence of cavity boundaries with particular consideration of the spatial growth rate, spectral output and rf conversion efficiency. Computations reveal that a well-defined cyclotron emission process occurs albeit with a low spatial growth rate compared with waveguide bounded simulations. The rf output is near perpendicular to the electron beam with a slight backward-wave character reflected in the spectral output with a well defined peak at 2.68 GHz, just below the relativistic electron cyclotron frequency. The corresponding rf conversion efficiency of 1.1% is comparable to waveguide bounded simulations and consistent with the predictions of kinetic theory that suggest efficient, spectrally well defined emission can be obtained from an electron horseshoe distribution in the absence of radiation boundaries.

  20. Formation of a conical distribution and intense ion heating in the presence of hydrogen cyclotron waves. [in earth ionosphere

    NASA Technical Reports Server (NTRS)

    Okuda, H.; Ashour-Abdalla, M.

    1981-01-01

    In the considered investigation, it is assumed that the field aligned currents are responsible for producing electrostatic harmonic cyclotron waves (EHC). Using a one-dimensional simulation model in which the electron velocity distribution is maintained by a constant injection of the initial distribution, it is shown that, in contrast to earlier initial value simulations, EHC waves grow to a large amplitude, resulting in the formation of an anisotropic ion velocity distribution. Both the heating rate and the anisotropy are in reasonable agreement with the quasi-linear theory, taking into account the cyclotron resonance. The results show that the saturation is due to the combined effects of wave induced diffusion in an electron velocity space and the heating of ions perpendicularly. Both these effects reduce the growth rate.

  1. Routine {sup 18}F{sup -} production with 180 {mu}A to 200 {mu}A target beam current on a GE PETtrace 800 cyclotron

    SciTech Connect

    Eberl, S.; Eriksson, T.; Svedberg, O.; Norling, J.; Henderson, D.; Lam, P.; Bourdier, T.; Fulham, M.

    2012-12-19

    Through upgrades and enhancements, which are now standard on current PETtrace 800 cyclotrons, a GE PETtrace cyclotron installed in 2002 has demonstrated reliable routine [{sup 18}F]FDG production at total target beam currents of 180 {mu}A without detriment to saturation and [{sup 18}F]FDG yields. Routine production at 200 {mu}A has been achieved and its evaluation is continuing. Self-shielded target using W/Cu alloy for the target body afforded a reduction in dose rate from the Havar foils by a factor of {approx} 8-10, reducing dose from the targets and need for removing targets during maintenance. The main activation product in the shield is {sup 187}W (T1/2 24 h). The {sup 60}Co ((T1/2 5.3 y) activation is about 250 times less at 24 h post EOB and is not considered a major issue despite its long half-life.

  2. Development of a pepper-pot device to determine the emittance of an ion beam generated by electron cyclotron resonance ion sources

    SciTech Connect

    Strohmeier, M.; Benitez, J. Y.; Leitner, D.; Lyneis, C. M.; Todd, D. S.; Bantel, M.

    2010-02-15

    This paper describes the recent development and commissioning of a pepper-pot emittance meter at the Lawrence Berkeley National Laboratory (LBNL). It is based on a potassium bromide (KBr) scintillator screen in combination with a charged coupled device camera. Pepper-pot scanners record the full four-dimensional transverse phase space emittances which are particularly interesting for electron cyclotron resonance ion sources. The strengths and limitations of evaluating emittances using optical pepper-pot scanners are described and systematic errors induced by the optical data acquisition system will be presented. Light yield tests of KBr exposed to different ion species and first emittance measurement data using ion beams extracted from the 6.4 GHz LBNL electron cyclotron resonance ion source are presented and discussed.

  3. Development of a pepper-pot device to determine the emittance of an ion beam generated by electron cyclotron resonance ion sources.

    PubMed

    Strohmeier, M; Benitez, J Y; Leitner, D; Lyneis, C M; Todd, D S; Bantel, M

    2010-02-01

    This paper describes the recent development and commissioning of a pepper-pot emittance meter at the Lawrence Berkeley National Laboratory (LBNL). It is based on a potassium bromide (KBr) scintillator screen in combination with a charged coupled device camera. Pepper-pot scanners record the full four-dimensional transverse phase space emittances which are particularly interesting for electron cyclotron resonance ion sources. The strengths and limitations of evaluating emittances using optical pepper-pot scanners are described and systematic errors induced by the optical data acquisition system will be presented. Light yield tests of KBr exposed to different ion species and first emittance measurement data using ion beams extracted from the 6.4 GHz LBNL electron cyclotron resonance ion source are presented and discussed. PMID:20192450

  4. Operation of the intensity monitors in beam transport lines at Fermilab during Run II¹

    DOE PAGESBeta

    Crisp, J.; Fellenz, B.; Fitzgerald, J.; Heikkinen, D.; Ibrahim, M. A.

    2011-10-06

    The intensity of charged particle beams at Fermilab must be kept within pre-determined safety and operational envelopes in part by assuring all beam within a few percent has been transported from any source to destination. Beam instensity monitors with toroidial pickups provide such beam intensity measurements in the transport lines between accelerators at FNAL. With Run II, much effort was made to continually improve the resolution and accuracy of the system.

  5. Phase and synchronous detector theory as applied to beam position and intensity measurements

    SciTech Connect

    Gilpatrick, J.D.

    1995-05-01

    A popular signal processing technique for beam position measurements uses the principle of amplitude-to-phase (AM/PM) conversion and phase detection. This technique processes position-sensitive beam-image-current probe-signals into output signals that are proportional to the beam`s position. These same probe signals may be summed and processed in a different fashion to provide output signals that are proportional to the peak beam current which is typically referred to as beam intensity. This paper derives the transfer functions for the AM/PM beam position and peak beam current processors.

  6. Truncated Thermal Equilibrium Distribution for Intense Beam Propagation

    SciTech Connect

    Ronald C. Davidson; Hong Qin; Steven M. Lund

    2003-02-26

    An intense charged-particle beam with directed kinetic energy ({lambda}{sub b}-1)m{sub b}c{sup 2} propagates in the z-direction through an applied focusing field with transverse focusing force modeled by F{sub foc} = -{lambda}{sub b}m{sub b}{omega}{sub beta}{sup 2} {perpendicular} x {perpendicular} in the smooth focusing approximation. This paper examines properties of the axisymmetric, truncated thermal equilibrium distribution F(sub)b(r,p perpendicular) = A exp (-H Perpendicular/T perpendicular (sub)b) = (H perpendicular-E(sub)b), where A, T perpendicular (sub)b, and E (sub)b are positive constants, and H perpendicular is the Hamiltonian for transverse particle motion. The equilibrium profiles for beam number density, n(sub)b(r) = * d{sup 2}pF(sub)b(r,p perpendicular), and transverse temperature, T perpendicular (sub)b(r) = * d{sup 2}p(p{sup 2} perpendicular/2 lambda (sbu)bm (sub)b)F(sub)b(r,p perpendicular), are calculated self-consistently including space-charge effects. Several properties of the equilibrium profiles are noteworthy. For example, the beam has a sharp outer edge radius r(sub)b with n(sub)b(r greater than or equal to rb) = 0, where r(sub)b depends on the value of E(sub)b/T (sub)perpendicular(sub)b. In addition, unlike the choice of a semi-Gaussian distribution, F{sup SG}(sub)b = A exp (-p{sup 2}(sub)perpendicular/2lambda(sub)bm(sub)bTperpendicular(sub)b) = (r-r(sub)b), the truncated thermal equilibrium distribution F(sub)b(r,p) depends on (r,p) only through the single-particle constant of the motion Hperpendiuclar and is therefore a true steady-state solution (*/*t = 0) of the nonlinear Vlasov-Maxwell equations.

  7. Analytical Solutions for the Nonlinear Longitudinal Drift Compression (Expansion) of Intense Charged Particle Beams

    SciTech Connect

    Edward A. Startsev; Ronald C. Davidson

    2004-04-09

    To achieve high focal spot intensities in heavy ion fusion, the ion beam must be compressed longitudinally by factors of ten to one hundred before it is focused onto the target. The longitudinal compression is achieved by imposing an initial velocity profile tilt on the drifting beam. In this paper, the problem of longitudinal drift compression of intense charged particle beams is solved analytically for the two important cases corresponding to a cold beam, and a pressure-dominated beam, using a one-dimensional warm-fluid model describing the longitudinal beam dynamics.

  8. The WARP Code: Modeling High Intensity Ion Beams

    SciTech Connect

    Grote, D P; Friedman, A; Vay, J L; Haber, I

    2004-12-09

    The Warp code, developed for heavy-ion driven inertial fusion energy studies, is used to model high intensity ion (and electron) beams. Significant capability has been incorporated in Warp, allowing nearly all sections of an accelerator to be modeled, beginning with the source. Warp has as its core an explicit, three-dimensional, particle-in-cell model. Alongside this is a rich set of tools for describing the applied fields of the accelerator lattice, and embedded conducting surfaces (which are captured at sub-grid resolution). Also incorporated are models with reduced dimensionality: an axisymmetric model and a transverse ''slice'' model. The code takes advantage of modern programming techniques, including object orientation, parallelism, and scripting (via Python). It is at the forefront in the use of the computational technique of adaptive mesh refinement, which has been particularly successful in the area of diode and injector modeling, both steady-state and time-dependent. In the presentation, some of the major aspects of Warp will be overviewed, especially those that could be useful in modeling ECR sources. Warp has been benchmarked against both theory and experiment. Recent results will be presented showing good agreement of Warp with experimental results from the STS500 injector test stand. Additional information can be found on the web page http://hif.lbl.gov/theory/WARP{_}summary.html.

  9. Static analysis of possible emittance growth of intense charged particle beams with thermal equilibrium distribution

    SciTech Connect

    Kikuchi, Takashi; Horioka, Kazuhiko

    2009-05-15

    Possible emittance growths of intense, nonuniform beams during a transport in a focusing channel are derived as a function of nonlinear field energy and space charge tune depression factors. The nonlinear field energy of the beam with thermal equilibrium distribution is estimated by considering the particle distribution across the cross section of the beam. The results show that the possible emittance growth can be suppressed by keeping the beam particle in thermal equilibrium distribution during the beam transport.

  10. In-situ determination of energy species yields of intense particle beams

    DOEpatents

    Kugel, Henry W.; Kaita, Robert

    1987-01-01

    An arrangement is provided for the in-situ determination of energy species yields of intense particle beams. The beam is directed onto a target surface of known composition, such that Rutherford backscattering of the beam occurs. The yield-energy characteristic response of the beam to backscattering from the target is analyzed using Rutherford backscattering techniques to determine the yields of energy species components of the beam.

  11. In-situ determination of energy species yields of intense particle beams

    DOEpatents

    Kugel, Henry W.; Kaita, Robert

    1987-03-03

    An arrangement is provided for the in-situ determination of energy species yields of intense particle beams. The beam is directed onto a target surface of known composition, such that Rutherford backscattering of the beam occurs. The yield-energy characteristic response of the beam to backscattering from the target is analyzed using Rutherford backscattering techniques to determine the yields of energy species components of the beam.

  12. Non-invasive measurments of intense relativistic electron beam size

    NASA Astrophysics Data System (ADS)

    Ekdahl, Carl; McCuistian, Trent; Moir, David; Rodriguez, Patrick; Broste, William; Johnson, Jeff

    2000-10-01

    To understand relativistic electron beam transport dynamics the size of the beam is often measured using invasive techniques such as imaging the Cerenkov or OTR light emitted from a screen inserted into the beam. These techniques would completely disrupt the DARHT 2 beam, so we are developing a non-invasive method using diamagnetic loops. We show that through conservation of canonical angular momentum the RMS radius of the beam can be found by measuring the magnetic flux excluded by the diamagnetic beam. Furthermore, this measurement is shown to be independent of the details of the beam radial current profile for DARHT 2 parameters. We present results from our test and calibration experiments, as well as results of beam radius measurements on the 20-MeV DARHT 1 accelerator.

  13. Development of an 18 GHz superconducting electron cyclotron resonance ion source at RCNP.

    PubMed

    Yorita, Tetsuhiko; Hatanaka, Kichiji; Fukuda, Mitsuhiro; Kibayashi, Mitsuru; Morinobu, Shunpei; Okamura, Hiroyuki; Tamii, Atsushi

    2008-02-01

    An 18 GHz superconducting electron cyclotron resonance ion source has recently been developed and installed in order to extend the variety and the intensity of ions at the RCNP coupled cyclotron facility. Production of several ions such as O, N, Ar, Kr, etc., is now under development and some of them have already been used for user experiments. For example, highly charged heavy ion beams like (86)Kr(21+,23+) and intense (16)O(5+,6+) and (15)N(6+) ion beams have been provided for experiments. The metal ion from volatile compounds method for boron ions has been developed as well. PMID:18315101

  14. Evolution of the axial electron cyclotron maser instability, with applications to solar microwave spikes

    NASA Technical Reports Server (NTRS)

    Vlahos, Loukas; Sprangle, Phillip

    1987-01-01

    The nonlinear evolution of cyclotron radiation from streaming and gyrating electrons in an external magnetic field is analyzed. The nonlinear dynamics of both the fields and the particles are treated fully relativistically and self-consistently. The model includes a background plasma and electrostatic effects. The analytical and numerical results show that a substantial portion of the beam particle energy can be converted to electromagnetic wave energy at frequencies far above the electron cyclotron frequency. In general, the excited radiation can propagate parallel to the magnetic field and, hence, escape gyrothermal absorption at higher cyclotron harmonics. The high-frequency Doppler-shifted cyclotron instability can have saturation efficiencies far higher than those associated with well-known instabilities of the electron cyclotron maser type. Although the analysis is general, the possibility of using this model to explain the intense radio emission observed from the sun is explored in detail.

  15. Electrostatic ion (hydrogen) cyclotron and ion acoustic wave instabilities in regions of upward field-aligned current and upward ion beams

    NASA Astrophysics Data System (ADS)

    Bergmann, R.

    1984-02-01

    An investigation is made into the stability of electrostatic hydrogen ion cyclotron and ion acoustic waves in a model plasma where an ion beam, population 2, and oppositely directed drifting electrons pass through a stationary ion background, population 1. The excited wave properties are then compared with the characteristics of the unstable modes observed on the S3-3 satellite. Three temperature regimes are studied: (1) Te greater than Ti2 much greater than Ti1, (2) Ti2 greater than Te not less than Ti1, and (3) Te approximately equal to Ti1 greater than Ti2. It is found that the ion beam acts as a free energy source only in regime 1. This regime is also highly unstable to the electrons as a free energy source. Unstable modes in regimes 2 and 3 seem to best satisfy the electrostatic hydrogen cyclotron wave (EHC) properties at 1 earth radius. For these cases the electrons are the free energy source, the beam supplies damping.

  16. 14 CFR 27.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 27.1395 Section 27.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 27.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  17. 14 CFR 27.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 27.1395 Section 27.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 27.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  18. 14 CFR 25.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 25.1395 Section 25.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 25.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  19. 14 CFR 25.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 25.1395 Section 25.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 25.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  20. 14 CFR 25.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 25.1395 Section 25.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 25.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  1. 14 CFR 29.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 29.1395 Section 29.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 29.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  2. 14 CFR 23.1395 - Maximum intensities in overlapping beams of position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maximum intensities in overlapping beams of position lights. 23.1395 Section 23.1395 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT... AIRPLANES Equipment Lights § 23.1395 Maximum intensities in overlapping beams of position lights....

  3. 14 CFR 23.1395 - Maximum intensities in overlapping beams of position lights.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Maximum intensities in overlapping beams of position lights. 23.1395 Section 23.1395 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT... AIRPLANES Equipment Lights § 23.1395 Maximum intensities in overlapping beams of position lights....

  4. 14 CFR 27.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 27.1395 Section 27.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 27.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  5. 14 CFR 27.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 27.1395 Section 27.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 27.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  6. 14 CFR 23.1395 - Maximum intensities in overlapping beams of position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum intensities in overlapping beams of position lights. 23.1395 Section 23.1395 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT... AIRPLANES Equipment Lights § 23.1395 Maximum intensities in overlapping beams of position lights....

  7. 14 CFR 23.1395 - Maximum intensities in overlapping beams of position lights.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maximum intensities in overlapping beams of position lights. 23.1395 Section 23.1395 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT... AIRPLANES Equipment Lights § 23.1395 Maximum intensities in overlapping beams of position lights....

  8. 14 CFR 29.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 29.1395 Section 29.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 29.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  9. 14 CFR 29.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 29.1395 Section 29.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 29.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  10. 14 CFR 29.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 29.1395 Section 29.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 29.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  11. 14 CFR 25.1395 - Maximum intensities in overlapping beams of forward and rear position lights.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum intensities in overlapping beams of forward and rear position lights. 25.1395 Section 25.1395 Aeronautics and Space FEDERAL AVIATION... Equipment Lights § 25.1395 Maximum intensities in overlapping beams of forward and rear position lights....

  12. Development of an Accelerator Mass Spectrometer based on a Cyclotron

    SciTech Connect

    Kim, Dogyun; Bhang, Hyeongchan; Kim, Jongwon

    2011-12-13

    An accelerator mass spectrometer based on a cyclotron has been developed, and a prototype of the injection beam line has been constructed. Mass resolution of the cyclotron is designed to be over 4000. A sawtooth RF buncher in the beam line and a flat-topping RF system for the cyclotron were utilized to enhance beam transmission efficiency, which is a primary factor for improvement compared to previous cyclotron mass spectrometers. The injection beam line comprises an ion source, Einzel lens, RF buncher, 90 deg. dipole magnet and a slit box containing beam diagnostic devices. A carbon beam was measured at the location of the slit box, and beam phase spaces will be measured. The design of a cyclotron magnet was done, and orbit tracking was carried out using cyclotron optics codes. A scheme of radial injection was chosen to place a beam on the equilibrium orbit of the cyclotron. The injection scheme will be optimized after the beam measurements are completed.

  13. Measurements of ion cyclotron range of frequencies mode converted wave intensity with phase contrast imaging in Alcator C-Mod and comparison with full-wave simulations

    SciTech Connect

    Tsujii, N.; Porkolab, M.; Bonoli, P. T.; Lin, Y.; Wright, J. C.; Wukitch, S. J.; Jaeger, E. F.; Green, D. L.; Harvey, R. W.

    2012-08-15

    Radio frequency waves in the ion cyclotron range of frequencies (ICRF) are widely used to heat tokamak plasmas. In ICRF heating schemes involving multiple ion species, the launched fast waves convert to ion cyclotron waves or ion Bernstein waves at the two-ion hybrid resonances. Mode converted waves are of interest as actuators to optimise plasma performance through current drive and flow drive. In order to describe these processes accurately in a realistic tokamak geometry, numerical simulations are essential, and it is important that these codes be validated against experiment. In this study, the mode converted waves were measured using a phase contrast imaging technique in D-H and D-{sup 3}He plasmas. The measured mode converted wave intensity in the D-{sup 3}He mode conversion regime was found to be a factor of {approx}50 weaker than the full-wave predictions. The discrepancy was reduced in the hydrogen minority heating regime, where mode conversion is weaker.

  14. New and improved apparatus and method for monitoring the intensities of charged-particle beams

    DOEpatents

    Varma, M.N.; Baum, J.W.

    1981-01-16

    Charged particle beam monitoring means are disposed in the path of a charged particle beam in an experimental device. The monitoring means comprise a beam monitoring component which is operable to prevent passage of a portion of beam, while concomitantly permitting passage of another portion thereof for incidence in an experimental chamber, and providing a signal (I/sub m/) indicative of the intensity of the beam portion which is not passed. Caibration means are disposed in the experimental chamber in the path of the said another beam portion and are operable to provide a signal (I/sub f/) indicative of the intensity thereof. Means are provided to determine the ratio (R) between said signals whereby, after suitable calibration, the calibration means may be removed from the experimental chamber and the intensity of the said another beam portion determined by monitoring of the monitoring means signal, per se.

  15. Collisional pumping for the production of intense spin-polarized neutral beams: target considerations. Revision

    SciTech Connect

    Stearns, J.W.; Burrell, C.F.; Kaplan, S.N.; Pyle, R.V.; Ruby, L.; Schlachter, A.S.

    1985-04-01

    Polarized beams at intensity levels heretofore not considered feasible have recently been proposed for heating and fueling fusion plasmas. Polarized-beam fueling could increase fusion rates by 50% as well as allow control of the directionality of the fusion products. A process which we have recently described, and called collisional pumping, promises to produce beams of polarized ions vastly more intense than producible by current methods.

  16. Radioactive by-products of a self-shielded cyclotron and the liquid target system for F-18 routine production.

    PubMed

    Kambali, I; Suryanto, H; Parwanto

    2016-06-01

    Routine production of F-18 radionuclide using proton beams accelerated in a cyclotron could potentially generate residual radioisotopes in the cyclotron vicinity which eventually become major safety concerns over radiation exposure to the workers. In this investigation, a typical 11-MeV proton, self-shielded cyclotron has been assessed for its residual radiation sources in the cyclotron's shielding, tank/chamber, cave wall as well as target system. Using a portable gamma ray spectroscopy system, the radiation measurement in the cyclotron environment has been carried out. Experimental results indicate that relatively long-lived radioisotopes such as Mn-54, Zn-65 and Eu-152 are detected in the inner and outer surface of the cyclotron shielding respectively while Mn-54 spectrum is observed around the cyclotron chamber. Weak intensity of Eu-152 radioisotope is again spotted in the inner and outer surface of the cyclotron cave wall. Angular distribution measurement of the Eu-152 shows that the intensity slightly drops with increasing observation angle relative to the proton beam incoming angle. In the target system, gamma rays from Co-56, Mn-52, Co-60, Mn-54, Ag-110 m are identified. TALYS-calculated nuclear cross-section data are used to study the origins of the radioactive by-products. PMID:26867652

  17. FINAL FOCUS ION BEAM INTENSITY FROM TUNGSTEN FOIL CALORIMETER AND SCINTILLATOR IN NDCX-I

    SciTech Connect

    Lidia, S.M.; Bieniosek, F.; Henestroza, E.; Ni, P.; Seidl, P.

    2010-04-30

    Laboratory high energy density experiments using ion beam drivers rely upon the delivery of high-current, high-brightness ion beams with high peak intensity onto targets. Solid-state scintillators are typically used to measure the ion beam spatial profile but they display dose-dependent degradation and aging effects. These effects produce uncertainties and limit the accuracy of measuring peak beam intensities delivered to the target. For beam tuning and characterizing the incident beam intensity, we have developed a cross-calibrating diagnostic suite that extends the upper limit of measurable peak intensity dynamic range. Absolute intensity calibration is obtained with a 3 {micro}m thick tungsten foil calorimeter and streak spectrometer. We present experimental evidence for peak intensity measures in excess of 400 kW/cm{sup 2} using a 0.3 MV, 25 mA, 5-20 {micro}sec K{sup +1} beam. Radiative models and thermal diffusion effects are discussed because they affect temporal and spatial resolution of beam intensity profiles.

  18. Arc-based smoothing of ion beam intensity on targets

    NASA Astrophysics Data System (ADS)

    Friedman, Alex

    2012-06-01

    By manipulating a set of ion beams upstream of a target, it is possible to arrange for a smoother deposition pattern, so as to achieve more uniform illumination of the target. A uniform energy deposition pattern is important for applications including ion-beam-driven high energy density physics and heavy-ion beam-driven inertial fusion energy ("heavy-ion fusion"). Here, we consider an approach to such smoothing that is based on rapidly "wobbling" each of the beams back and forth along a short arc-shaped path, via oscillating fields applied upstream of the final pulse compression. In this technique, uniformity is achieved in the time-averaged sense; this is sufficient provided the beam oscillation timescale is short relative to the hydrodynamic timescale of the target implosion. This work builds on two earlier concepts: elliptical beams applied to a distributed-radiator target [D. A. Callahan and M. Tabak, Phys. Plasmas 7, 2083 (2000)] and beams that are wobbled so as to trace a number of full rotations around a circular or elliptical path [R. C. Arnold et al., Nucl. Instrum. Methods 199, 557 (1982)]. Here, we describe the arc-based smoothing approach and compare it to results obtainable using an elliptical-beam prescription. In particular, we assess the potential of these approaches for minimization of azimuthal asymmetry, for the case of a ring of beams arranged on a cone. It is found that, for small numbers of beams on the ring, the arc-based smoothing approach offers superior uniformity. In contrast with the full-rotation approach, arc-based smoothing remains usable when the geometry precludes wobbling the beams around a full circle, e.g., for the X-target [E. Henestroza, B. G. Logan, and L. J. Perkins, Phys. Plasmas 18, 032702 (2011)] and some classes of distributed-radiator targets.

  19. Arc-based smoothing of ion beam intensity on targets

    SciTech Connect

    Friedman, Alex

    2012-06-20

    Manipulating a set of ion beams upstream of a target, makes it possible to arrange a smoother deposition pattern, so as to achieve more uniform illumination of the target. A uniform energy deposition pattern is important for applications including ion-beam-driven high energy density physics and heavy-ion beam-driven inertial fusion energy (“heavy-ion fusion”). Here, we consider an approach to such smoothing that is based on rapidly “wobbling” each of the beams back and forth along a short arc-shaped path, via oscillating fields applied upstream of the final pulse compression. In this technique, uniformity is achieved in the time-averaged sense; this is sufficient provided the beam oscillation timescale is short relative to the hydrodynamic timescale of the target implosion. This work builds on two earlier concepts: elliptical beams applied to a distributed-radiator target [D. A. Callahan and M. Tabak, Phys. Plasmas 7, 2083 (2000)] and beams that are wobbled so as to trace a number of full rotations around a circular or elliptical path [R. C. Arnold et al., Nucl. Instrum. Methods 199, 557 (1982)]. Here, we describe the arc-based smoothing approach and compare it to results obtainable using an elliptical-beam prescription. In particular, we assess the potential of these approaches for minimization of azimuthal asymmetry, for the case of a ring of beams arranged on a cone. We also found that, for small numbers of beams on the ring, the arc-based smoothing approach offers superior uniformity. In contrast with the full-rotation approach, arc-based smoothing remains usable when the geometry precludes wobbling the beams around a full circle, e.g., for the X-target [E. Henestroza, B. G. Logan, and L. J. Perkins, Phys. Plasmas 18, 032702 (2011)] and some classes of distributed-radiator targets.

  20. Arc-based smoothing of ion beam intensity on targets

    SciTech Connect

    Friedman, Alex

    2012-06-15

    By manipulating a set of ion beams upstream of a target, it is possible to arrange for a smoother deposition pattern, so as to achieve more uniform illumination of the target. A uniform energy deposition pattern is important for applications including ion-beam-driven high energy density physics and heavy-ion beam-driven inertial fusion energy ('heavy-ion fusion'). Here, we consider an approach to such smoothing that is based on rapidly 'wobbling' each of the beams back and forth along a short arc-shaped path, via oscillating fields applied upstream of the final pulse compression. In this technique, uniformity is achieved in the time-averaged sense; this is sufficient provided the beam oscillation timescale is short relative to the hydrodynamic timescale of the target implosion. This work builds on two earlier concepts: elliptical beams applied to a distributed-radiator target [D. A. Callahan and M. Tabak, Phys. Plasmas 7, 2083 (2000)] and beams that are wobbled so as to trace a number of full rotations around a circular or elliptical path [R. C. Arnold et al., Nucl. Instrum. Methods 199, 557 (1982)]. Here, we describe the arc-based smoothing approach and compare it to results obtainable using an elliptical-beam prescription. In particular, we assess the potential of these approaches for minimization of azimuthal asymmetry, for the case of a ring of beams arranged on a cone. It is found that, for small numbers of beams on the ring, the arc-based smoothing approach offers superior uniformity. In contrast with the full-rotation approach, arc-based smoothing remains usable when the geometry precludes wobbling the beams around a full circle, e.g., for the X-target [E. Henestroza, B. G. Logan, and L. J. Perkins, Phys. Plasmas 18, 032702 (2011)] and some classes of distributed-radiator targets.

  1. Arc-based smoothing of ion beam intensity on targets

    DOE PAGESBeta

    Friedman, Alex

    2012-06-20

    Manipulating a set of ion beams upstream of a target, makes it possible to arrange a smoother deposition pattern, so as to achieve more uniform illumination of the target. A uniform energy deposition pattern is important for applications including ion-beam-driven high energy density physics and heavy-ion beam-driven inertial fusion energy (“heavy-ion fusion”). Here, we consider an approach to such smoothing that is based on rapidly “wobbling” each of the beams back and forth along a short arc-shaped path, via oscillating fields applied upstream of the final pulse compression. In this technique, uniformity is achieved in the time-averaged sense; this ismore » sufficient provided the beam oscillation timescale is short relative to the hydrodynamic timescale of the target implosion. This work builds on two earlier concepts: elliptical beams applied to a distributed-radiator target [D. A. Callahan and M. Tabak, Phys. Plasmas 7, 2083 (2000)] and beams that are wobbled so as to trace a number of full rotations around a circular or elliptical path [R. C. Arnold et al., Nucl. Instrum. Methods 199, 557 (1982)]. Here, we describe the arc-based smoothing approach and compare it to results obtainable using an elliptical-beam prescription. In particular, we assess the potential of these approaches for minimization of azimuthal asymmetry, for the case of a ring of beams arranged on a cone. We also found that, for small numbers of beams on the ring, the arc-based smoothing approach offers superior uniformity. In contrast with the full-rotation approach, arc-based smoothing remains usable when the geometry precludes wobbling the beams around a full circle, e.g., for the X-target [E. Henestroza, B. G. Logan, and L. J. Perkins, Phys. Plasmas 18, 032702 (2011)] and some classes of distributed-radiator targets.« less

  2. Average intensity and directionality of partially coherent model beams propagating in turbulent ocean.

    PubMed

    Wu, Yuqian; Zhang, Yixin; Zhu, Yun

    2016-08-01

    We studied Gaussian beams with three different partially coherent models, including the Gaussian-Schell model (GSM), Laguerre-Gaussian Schell model (LGSM), and Bessel-Gaussian Schell model (BGSM), propagating through oceanic turbulence. The expressions of average intensity, beam spreading, and beam wander for GSM, LGSM, and BGSM beams in the paraxial channel are derived. We make a contrast for the three models in numerical simulations and find that the GSM beam has smaller spreading than the others, and the LGSM beam needs longer propagation distance to transform into a well-like profile of average intensity than the BGSM beam in the same conditions. The salinity fluctuation has a greater contribution to the wander of LGSM and BGSM beams than that of the temperature fluctuation. Our results can be helpful in the design of an optical wireless communication link operating in oceanic environment. PMID:27505642

  3. Effect of turbulent atmosphere on the on-axis average intensity of Pearcey–Gaussian beam

    NASA Astrophysics Data System (ADS)

    F, Boufalah; L, Dalil-Essakali; H, Nebdi; A, Belafhal

    2016-06-01

    The propagation characteristics of the Pearcey–Gaussian (PG) beam in turbulent atmosphere are investigated in this paper. The Pearcey beam is a new kind of paraxial beam, based on the Pearcey function of catastrophe theory, which describes diffraction about a cusp caustic. By using the extended Huygens–Fresnel integral formula in the paraxial approximation and the Rytov theory, an analytical expression of axial intensity for the considered beam family is derived. Some numerical results for PG beam propagating in atmospheric turbulence are given by studying the influences of some factors, including incident beam parameters and turbulence strengths.

  4. Self-pinched transport of an intense proton beam

    SciTech Connect

    Ottinger, P. F.; Young, F. C.; Stephanakis, S. J.; Rose, D. V.; Neri, J. M.; Weber, B. V.; Myers, M. C.; Hinshelwood, D. D.; Mosher, D.; Olson, C. L.

    2000-01-01

    Ion beam self-pinched transport (SPT) experiments have been carried out using a 1.1-MeV, 100-kA proton beam. A Rutherford scattering diagnostic and a LiF nuclear activation diagnostic measured the number of protons within a 5 cm radius at 50 cm into the transport region that was filled with low-pressure helium. Time-integrated signals from both diagnostics indicate self-pinching of the ion beam in a helium pressure window between 35 and 80 mTorr. Signals from these two diagnostics are consistent with ballistic transport at pressures above and below this SPT pressure window. Interferometric measurements of electron densities during beam injection into vacuum are consistent with ballistic transport with co-moving electrons. Interferometric measurements for beam injection into helium show that the electron density increases quadratically with pressure through the SPT window and roughly linearly with pressure above the SPT window. The ionization fraction of the helium plateaus at about 1.5% for pressures above 80 mTorr. In the SPT window, the electron density is 3 to 20 times the beam density. Numerical simulations of these beam transport experiments produce results that are in qualitative agreement with the experimental measurements. (c) 2000 American Institute of Physics.

  5. Combined infrared multiphoton dissociation and electron-capture dissociation using co-linear and overlapping beams in Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Mihalca, Romulus; van der Burgt, Yuri E M; McDonnell, Liam A; Duursma, Marc; Cerjak, Iliya; Heck, Albert J R; Heeren, Ron M A

    2006-01-01

    A novel set-up for Fourier transform ion cyclotron resonance mass spectrometry (FTICR) is reported for simultaneous infrared multiphoton dissociation (IRMPD) and electron-capture dissociation (ECD). An unmodified electron gun ensures complete, on-axis overlap between the electron and the photon beams. The instrumentation, design and implementation of this novel approach are described. In this configuration the IR beam is directed into the ICR cell using a pneumatically actuated mirror inserted into the ion-optical path. Concept validation was made using different combinations of IRMPD and ECD irradiation events on two standard peptides. The ability to perform efficient IRMPD, ECD and especially simultaneous IRMPD and ECD using lower irradiation times is demonstrated. The increase in primary sequence coverage, with the combined IRMPD and ECD set-up, also increases the confidence in peptide and protein assignments. PMID:16705647

  6. Note: Design and initial results of a multi-pulsed intense electron beam source

    NASA Astrophysics Data System (ADS)

    Xia, L.; Zhang, H.; Yang, A.; Shen, Y.; Wang, W.; Wen, L.; Zhang, K.; Shi, J.; Zhang, L.; Deng, J.

    2014-06-01

    A multi-pulsed intense electron beam source is introduced, including the design and the initial experimental results. The source can generate a burst of three pulses of intense electron beams with energy of 2-3 MeV and beam intensities of around 2.5 kA. An inductive adder is chosen to generate the pulsed diode voltages and a dispenser cathode is chosen to emit electron beams. The test results indicate that the design of the source is reliable. The multi-pulsed diode voltage is up to 2.5 MV and the beam intensities are more than 2 kA at the exit of the source with small variation.

  7. Note: Design and initial results of a multi-pulsed intense electron beam source.

    PubMed

    Xia, L; Zhang, H; Yang, A; Shen, Y; Wang, W; Wen, L; Zhang, K; Shi, J; Zhang, L; Deng, J

    2014-06-01

    A multi-pulsed intense electron beam source is introduced, including the design and the initial experimental results. The source can generate a burst of three pulses of intense electron beams with energy of 2-3 MeV and beam intensities of around 2.5 kA. An inductive adder is chosen to generate the pulsed diode voltages and a dispenser cathode is chosen to emit electron beams. The test results indicate that the design of the source is reliable. The multi-pulsed diode voltage is up to 2.5 MV and the beam intensities are more than 2 kA at the exit of the source with small variation. PMID:24985872

  8. Intense ion beams accelerated by relativistic laser plasmas

    NASA Astrophysics Data System (ADS)

    Roth, Markus; Cowan, Thomas E.; Gauthier, Jean-Claude J.; Allen, Matthew; Audebert, Patrick; Blazevic, Abel; Fuchs, Julien; Geissel, Matthias; Hegelich, Manuel; Karsch, S.; Meyer-ter-Vehn, Jurgen; Pukhov, Alexander; Schlegel, Theodor

    2001-12-01

    We have studied the influence of the target properties on laser-accelerated proton and ion beams generated by the LULI multi-terawatt laser. A strong dependence of the ion emission on the surface conditions, conductivity, shape and material of the thin foil targets were observed. We have performed a full characterization of the ion beam using magnetic spectrometers, Thompson parabolas, radiochromic film and nuclear activation techniques. The strong dependence of the ion beam acceleration on the conditions on the target back surface was found in agreement with theoretical predictions based on the target normal sheath acceleration (TNSA) mechanism. Proton kinetic energies up to 25 MeV have been observed.

  9. Emission of an intense electron beam from a ceramic honeycomb

    NASA Astrophysics Data System (ADS)

    Friedman, M.; Myers, M.; Hegeler, F.; Swanekamp, S. B.; Sethian, J. D.; Ludeking, L.

    2003-01-01

    Inserting a slab of honeycomb ceramic in front of the emitting surface of a large-area cathode improves the electron beam emission uniformity, decreases the beam current rise and fall times, and maintains a more constant diode impedance. Moreover, changing the cathode material from velvet to carbon fiber achieved a more robust cathode that starts to emit at a higher electric field without a degradation in beam uniformity. In addition, an 80% reduction in the postshot diode pressure was also observed when gamma alumina was deposited on the ceramic. A possible explanation is that reabsorption and recycling of adsorbed gases takes place.

  10. Systems for controlling the intensity variations in a laser beam and for frequency conversion thereof

    DOEpatents

    Skupsky, Stanley; Craxton, R. Stephen; Soures, John

    1990-01-01

    In order to control the intensity of a laser beam so that its intensity varies uniformly and provides uniform illumination of a target, such as a laser fusion target, a broad bandwidth laser pulse is spectrally dispersed spatially so that the frequency components thereof are spread apart. A disperser (grating) provides an output beam which varies spatially in wavelength in at least one direction transverse to the direction of propagation of the beam. Temporal spread (time delay) across the beam is corrected by using a phase delay device (a time delay compensation echelon). The dispersed beam may be amplified with laser amplifiers and frequency converted (doubled, tripled or quadrupled in frequency) with nonlinear optical elements (birefringent crystals). The spectral variation across the beam is compensated by varying the angle of incidence on one of the crystals with respect to the crystal optical axis utilizing a lens which diverges the beam. Another lens after the frequency converter may be used to recollimate the beam. The frequency converted beam is recombined so that portions of different frequency interfere and, unlike interference between waves of the same wavelength, there results an intensity pattern with rapid temoral oscillations which average out rapidly in time thereby producing uniform illumination on target. A distributed phase plate (also known as a random phase mask), through which the spectrally dispersed beam is passed and then focused on a target, is used to provide the interference pattern which becomes nearly modulation free and uniform in intensity in the direction of the spectral variation.

  11. Systems for controlling the intensity variations in a laser beam and for frequency conversion thereof

    DOEpatents

    Skupsky, S.; Craxton, R.S.; Soures, J.

    1990-10-02

    In order to control the intensity of a laser beam so that its intensity varies uniformly and provides uniform illumination of a target, such as a laser fusion target, a broad bandwidth laser pulse is spectrally dispersed spatially so that the frequency components thereof are spread apart. A disperser (grating) provides an output beam which varies spatially in wavelength in at least one direction transverse to the direction of propagation of the beam. Temporal spread (time delay) across the beam is corrected by using a phase delay device (a time delay compensation echelon). The dispersed beam may be amplified with laser amplifiers and frequency converted (doubled, tripled or quadrupled in frequency) with nonlinear optical elements (birefringent crystals). The spectral variation across the beam is compensated by varying the angle of incidence on one of the crystals with respect to the crystal optical axis utilizing a lens which diverges the beam. Another lens after the frequency converter may be used to recollimate the beam. The frequency converted beam is recombined so that portions of different frequency interfere and, unlike interference between waves of the same wavelength, there results an intensity pattern with rapid temporal oscillations which average out rapidly in time thereby producing uniform illumination on target. A distributed phase plate (also known as a random phase mask), through which the spectrally dispersed beam is passed and then focused on a target, is used to provide the interference pattern which becomes nearly modulation free and uniform in intensity in the direction of the spectral variation. 16 figs.

  12. Study of a final focus system for high intensity beams

    SciTech Connect

    Henestroza, Enrique; Eylon, Shmuel; Roy, Prabir K.; Yu, Simon S.; Bieniosek, Frank M.; Shuman, Derek B.; Waldron, William L.

    2004-06-01

    The NTX experiment at the Heavy Ion Fusion Virtual National Laboratory is exploring the performance of neutralized final focus systems for high perveance heavy ion beams. The final focus scenario in an HIF driver consists of several large aperture quadrupole magnets followed by a drift section in which the beam space charge is neutralized by a plasma. This beam is required to hit a millimeter-sized target spot at the end of the drift section. The objective of the NTX experiments and associated theory and simulations is to study the various physical mechanisms that determine the final spot size (radius r{sub s}) at a given distance (f) from the end of the last quadrupole. In a fusion driver, f is the standoff distance required to keep the chamber wall and superconducting magnets properly protected. The NTX final quadrupole focusing system produces a converging beam at the entrance to the neutralized drift section where it focuses to a small spot. The final spot is determined by the conditions of the beam entering the quadrupole section, the beam dynamics in the magnetic lattice, and the plasma neutralization dynamics in the drift section. The main issues are the control of emittance growth due to high order fields from magnetic multipoles and image fields. In this paper, we will describe the theoretical and experimental aspects of the beam dynamics in the quadrupole lattice, and how these physical effects influence the final beam size. In particular, we present theoretical and experimental results on the dependence of final spot size on geometric aberrations and perveance.

  13. Studies on low energy beam transport for high intensity high charged ions at IMP

    SciTech Connect

    Yang, Y. Lu, W.; Fang, X.; University of Chinese Academy of Sciences, Beijing 100039 ; Sun, L. T.; Hu, Q.; Cao, Y.; Feng, Y. C.; Zhang, X. Z.; Zhao, H. W.; Xie, D. Z.

    2014-02-15

    Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou (SECRAL) is an advanced fully superconducting ECR ion source at IMP designed to be operational at the microwave frequency of 18–24 GHz. The existing SECRAL beam transmission line is composed of a solenoid lens and a 110° analyzing magnet. Simulations of particle tracking with 3D space charge effect and realistic 3D magnetic fields through the line were performed using particle-in-cell code. The results of the beam dynamics show that such a low energy beam is very sensitive to the space charge effect and significantly suffers from the second-order aberration of the analyzing magnet resulting in large emittance. However, the second-order aberration could be reduced by adding compensating sextupole components in the beam line. On this basis, a new 110° analyzing magnet with relatively larger acceptance and smaller aberration is designed and will be used in the design of low energy beam transport line for a new superconducting ECR ion source SECRAL-II. The features of the analyzer and the corresponding beam trajectory calculation will be detailed and discussed in this paper.

  14. Studies on low energy beam transport for high intensity high charged ions at IMP.

    PubMed

    Yang, Y; Sun, L T; Hu, Q; Cao, Y; Lu, W; Feng, Y C; Fang, X; Zhang, X Z; Zhao, H W; Xie, D Z

    2014-02-01

    Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou (SECRAL) is an advanced fully superconducting ECR ion source at IMP designed to be operational at the microwave frequency of 18-24 GHz. The existing SECRAL beam transmission line is composed of a solenoid lens and a 110° analyzing magnet. Simulations of particle tracking with 3D space charge effect and realistic 3D magnetic fields through the line were performed using particle-in-cell code. The results of the beam dynamics show that such a low energy beam is very sensitive to the space charge effect and significantly suffers from the second-order aberration of the analyzing magnet resulting in large emittance. However, the second-order aberration could be reduced by adding compensating sextupole components in the beam line. On this basis, a new 110° analyzing magnet with relatively larger acceptance and smaller aberration is designed and will be used in the design of low energy beam transport line for a new superconducting ECR ion source SECRAL-II. The features of the analyzer and the corresponding beam trajectory calculation will be detailed and discussed in this paper. PMID:24593453

  15. Progress toward a microsecond duration, repetitive, intense-ion beam for active spectroscopic measurements on ITER

    SciTech Connect

    Davis, H.A.; Bartsch, R.R.; Barnes, C.W.

    1996-06-01

    The authors describe the design of an intense, pulsed, repetitive, neutral beam based on magnetically insulated diode technology for injection into ITER for spectroscopic measurements of thermalizing alpha particle and thermal helium density profiles, ion temperature, plasma rotation, and low Z impurity concentrations in the confinement region. The beam is being developed to enhance low signal-to-noise ratios expected with conventional steady-state ion beams because of severe beam attenuation and intense bremstrahlung emission. A 5 GW (e.g., 100 keV, 50 kA) one-microsecond-duration beam would increase the signal by 10{sup 3} compared to a conventional 5 MW beam with signal-to-noise ratios comparable to those from a chopped conventional beam in one second.

  16. A new luminescence beam profile monitor for intense proton and heavy ion beams

    SciTech Connect

    Tsang,T.; Bellavia, S.; Connolly, R.; Gassner, D.; Makdisi, Y.; Russo, T.; Thieberger, P.; Trbojevic, D.; Zelenski, A.

    2008-10-01

    A new luminescence beam profile monitor is realized in the polarized hydrogen gas jet target at the Relativistic Heavy Ion Collider (RHIC) facility. In addition to the spin polarization of the proton beam being routinely measured by the hydrogen gas jet, the luminescence produced by beam-hydrogen excitation leads to a strong Balmer series lines emission. A selected hydrogen Balmer line is spectrally filtered and imaged to produce the transverse RHIC proton beam shape with unprecedented details on the RHIC beam profile. Alternatively, when the passage of the high energy RHIC gold ion beam excited only the residual gas molecules in the beam path, sufficient ion beam induced luminescence is produced and the transverse gold ion beam profile is obtained. The measured transverse beam sizes and the calculated emittances provide an independent confirmation of the RHIC beam characteristics and to verify the emittance conservation along the RHIC accelerator. This optical beam diagnostic technique by making use of the beam induced fluorescence from injected or residual gas offers a truly noninvasive particle beam characterization, and provides a visual observation of proton and heavy ion beams. Combined with a longitudinal bunch measurement system, a 3-dimensional spatial particle beam profile can be reconstructed tomographically.

  17. High intensity high charge state ion beam production with an evaporative cooling magnet ECRIS.

    PubMed

    Lu, W; Qian, C; Sun, L T; Zhang, X Z; Fang, X; Guo, J W; Yang, Y; Feng, Y C; Ma, B H; Xiong, B; Ruan, L; Zhao, H W; Zhan, W L; Xie, D

    2016-02-01

    LECR4 (Lanzhou ECR ion source No. 4) is a room temperature electron cyclotron resonance ion source, designed to produce high current, high charge state ion beams for the SSC-LINAC injector (a new injector for sector separated cyclotron) at the Institute of Modern Physics. LECR4 also serves as a PoP machine for the application of evaporative cooling technology in accelerator field. To achieve those goals, LECR4 ECR ion source has been optimized for the operation at 18 GHz. During 2014, LECR4 ion source was commissioned at 18 GHz microwave of 1.6 kW. To further study the influence of injection stage to the production of medium and high charge state ion beams, in March 2015, the injection stage with pumping system was installed, and some optimum results were produced, such as 560 eμA of O(7+), 620 eμA of Ar(11+), 430 eμA of Ar(12+), 430 eμA of Xe(20+), and so on. The comparison will be discussed in the paper. PMID:26931956

  18. High intensity high charge state ion beam production with an evaporative cooling magnet ECRIS

    NASA Astrophysics Data System (ADS)

    Lu, W.; Qian, C.; Sun, L. T.; Zhang, X. Z.; Fang, X.; Guo, J. W.; Yang, Y.; Feng, Y. C.; Ma, B. H.; Xiong, B.; Ruan, L.; Zhao, H. W.; Zhan, W. L.; Xie, D.

    2016-02-01

    LECR4 (Lanzhou ECR ion source No. 4) is a room temperature electron cyclotron resonance ion source, designed to produce high current, high charge state ion beams for the SSC-LINAC injector (a new injector for sector separated cyclotron) at the Institute of Modern Physics. LECR4 also serves as a PoP machine for the application of evaporative cooling technology in accelerator field. To achieve those goals, LECR4 ECR ion source has been optimized for the operation at 18 GHz. During 2014, LECR4 ion source was commissioned at 18 GHz microwave of 1.6 kW. To further study the influence of injection stage to the production of medium and high charge state ion beams, in March 2015, the injection stage with pumping system was installed, and some optimum results were produced, such as 560 eμA of O7+, 620 eμA of Ar11+, 430 eμA of Ar12+, 430 eμA of Xe20+, and so on. The comparison will be discussed in the paper.

  19. Longitudinal confinement and matching of an intense electron beam

    NASA Astrophysics Data System (ADS)

    Beaudoin, B.; Haber, I.; Kishek, R. A.; Bernal, S.; Koeth, T.; Sutter, D.; O'Shea, P. G.; Reiser, M.

    2011-01-01

    An induction cell has successfully been demonstrated to longitudinally confine a space-charge dominated bunch for over a thousand turns (>11.52 km) in the University of Maryland Electron Ring [Haber et al., Nucl. Instrum. Methods Phys. Res. A 606, 64 (2009) and R. A. Kishek et al., Int. J. Mod. Phys. A 22, 3838 (2007)]. With the use of synchronized periodic focusing fields, the beam is confined for multiple turns overcoming the longitudinal space-charge forces. Experimental results show that an optimum longitudinal match is obtained when the focusing frequency for containment of the 0.52 mA beam is applied at every fifth turn. Containment of the beam bunch is achievable at lower focusing frequencies, at the cost of a reduction in the transported charge from the lack of sufficient focusing. Containment is also obtainable, if the confinement fields overfocus the bunch, exciting multiple waves at the bunch ends, which propagate into the central region of the beam, distorting the overall constant current beam shape.

  20. Population inversions in ablation plasmas generated by intense electron beams

    NASA Astrophysics Data System (ADS)

    Gilgenbach, R. M.; Kammash, T.; Brake, M. L.

    1988-11-01

    Experiments during the past three years have concerned the generation and spectroscopic study of electron beam-driven carbon plasmas in order to explore the production of optical and ultraviolet radiation from nonequilibrium populations. The output of MELBA (Michigan Electron Long Beam Accelerator), has been connected to an electron beam diode consisting of an aluminum (or brass) cathode stalk and a carbon anode. Magnetic field coils have been designed, procured, and utilized to focus the electron beam. A side viewing port permitted spectroscopic diagnostics to view across the surface of the anode. Spectroscopic diagnosis has been performed using a 1 m spectrograph capable of operation from the vacuum ultraviolet through the visible. This spectrograph is coupled to a 1024 channel optical multichannel analyzer. Spectra taken during the initial 400 ns period of the e-beam pulse showed a low effective charge plasma with primarily molecular components (C2, CH) as well as atomic hydrogen and singly ionized carbon (CII). When the generator pulse was crowbarred after the first 400 ns, the spectra revealed a continuation of the low charge state plasma.

  1. Field energy and RMS emittance in intense particle beams

    SciTech Connect

    Wangler, T.P.; Crandall, K.R.; Mills, R.S.; Reiser, M.

    1986-04-25

    An equation is presented for continuous beam with azimuthal symmetry and continuous linear focusing; the equation expresses a relationship between the rate of change for squared rms emittance and the rate of change for a quantity we call the nonlinear field energy. The nonlinear field energy depends on the shape of the charge distribution and corresponds to the residual field energy possessed by beams with nonuniform charge distributions. The equation can be integrated for the case of an rms matched beam to yield a formula for space-charge-induced emittance growth that we have tested numerically for a variety of initial distributions. The results provide a framework for discussing the scaling of rms emittance growth and an explanation for the well-established lower limit on output emittance.

  2. Development of a Negative Hydrogen Ion Source for Spatial Beam Profile Measurement of a High Intensity Positive Ion Beam

    SciTech Connect

    Shinto, Katsuhiro; Wada, Motoi; Nishida, Tomoaki; Demura, Yasuhiro; Sasaki, Daichi; Tsumori, Katsuyoshi; Nishiura, Masaki; Kaneko, Osamu; Kisaki, Masashi; Sasao, Mamiko

    2011-09-26

    We have been developing a negative hydrogen ion (H{sup -} ion) source for a spatial beam profile monitor of a high intensity positive ion beam as a new diagnostic tool. In case of a high intensity continuous-wave (CW) deuteron (D{sup +}) beam for the International Fusion Materials Irradiation Facility (IFMIF), it is difficult to measure the beam qualities in the severe high radiation environment during about one-year cyclic operation period. Conventional techniques are next to unusable for diagnostics in the operation period of about eleven months and for maintenance in the one-month shutdown period. Therefore, we have proposed an active beam probe system by using a negative ion beam and started an experimental study for the proof-of-principle (PoP) of the new spatial beam profile monitoring tool. In this paper, we present the status of development of the H{sup -} ion source as a probe beam source for the PoP experiment.

  3. Production of intense beams of polarized negative hydrogen ions by double charge exchange in alkali vapour

    NASA Astrophysics Data System (ADS)

    Gruëbler, W.; Schmelzbach, P. A.

    1983-07-01

    The intensity of the polarized negative hydrogen ion beam of the ETHZ atomic beam polarized ion source has been substantially improved by a new double charge exchange device. Increasing the diameter of the charge exchange canal to 1.4 cm results in a beam output of the source of 6 μA of polarized negative hydrogen ions. Further improvements of the charge exchanger are proposed and discussed. With an updated design of the atomic beam apparatus, beams of 0.5 mA polarized negative hydrogen ions may be obtained from such a source.

  4. Propagation instabilities of high-intensity laser-produced electron beams.

    PubMed

    Tatarakis, M; Beg, F N; Clark, E L; Dangor, A E; Edwards, R D; Evans, R G; Goldsack, T J; Ledingham, K W D; Norreys, P A; Sinclair, M A; Wei, M-S; Zepf, M; Krushelnick, K

    2003-05-01

    Measurements of energetic electron beams generated from ultrahigh intensity laser interactions (I>10(19) W/cm(2)) with dense plasmas are discussed. These interactions have been shown to produce very directional beams, although with a broad energy spectrum. In the regime where the beam density approaches the density of the background plasma, we show that these beams are unstable to filamentation and "hosing" instabilities. Particle-in-cell simulations also indicate the development of such instabilities. This is a regime of particular interest for inertial confinement fusion applications of these beams (i.e., "fast ignition"). PMID:12786076

  5. Compact integrated X-ray intensity and beam position monitor based on rare gas scintillation

    SciTech Connect

    Revesz, Peter; Ruff, Jacob; Dale, Darren; Krawczyk, Thomas

    2013-05-15

    We have created and tested a compact integrated X-ray beam intensity and position monitor using Ar-gas scintillation. The light generated inside the device's cavity is detected by diametrically opposed PIN diodes located above and below the beam. The intensity is derived from the sum of the top and bottom signals, while the beam position is calculated from the difference-over-sum of the two signals. The device was tested at Cornell High Energy Synchrotron Source with both 17 keV and 59 keV x-rays. For intensity monitoring, the Ar-scintillation monitor performance is comparable to standard ion chambers in terms of precision. As an X-ray beam position monitor the new device response is linear with vertical beam position over a 2 mm span with a precision of 2 {mu}m.

  6. Key elements of space charge compensation on a low energy high intensity beam injector

    SciTech Connect

    Peng Shixiang; Lu Pengnan; Ren Haitao; Zhao Jie; Chen Jia; Xu Yuan; Guo Zhiyu; Chen Jia'er; Zhao Hongwei; Sun Liangting

    2013-03-15

    Space charge effect (SCE) along the beam line will decrease beam quality. Space charge compensation (SCC) with extra gas injection is a high-efficiency method to reduce SCE. In this paper, we will report the experimental results on the beam profile, potential distribution, beam emittance, and beam transmission efficiency of a 35 keV/90 mA H{sup +} beam and a 40 keV/10 mA He{sup +} beam compensated by Ar/Kr. The influence of gas type, gas flow, and injection location will be discussed. Emphasis is laid on the consideration of SCC when designing and commissioning a high intensity ion beam injector. Based on measured data, a new definition of space charge compensation degree is proposed.

  7. Key elements of space charge compensation on a low energy high intensity beam injector.

    PubMed

    Peng, Shixiang; Lu, Pengnan; Ren, Haitao; Zhao, Jie; Chen, Jia; Xu, Yuan; Guo, Zhiyu; Chen, Jia'er; Zhao, Hongwei; Sun, Liangting

    2013-03-01

    Space charge effect (SCE) along the beam line will decrease beam quality. Space charge compensation (SCC) with extra gas injection is a high-efficiency method to reduce SCE. In this paper, we will report the experimental results on the beam profile, potential distribution, beam emittance, and beam transmission efficiency of a 35 keV∕90 mA H(+) beam and a 40 keV∕10 mA He(+) beam compensated by Ar∕Kr. The influence of gas type, gas flow, and injection location will be discussed. Emphasis is laid on the consideration of SCC when designing and commissioning a high intensity ion beam injector. Based on measured data, a new definition of space charge compensation degree is proposed. PMID:23556812

  8. Spatial and spectral coherence in propagating high-intensity twin beams

    PubMed Central

    Haderka, Ondřej; Machulka, Radek; Peřina, Jan; Allevi, Alessia; Bondani, Maria

    2015-01-01

    Spatial and spectral coherence of high-intensity twin-beam states propagating from the near-field to the far-field configurations is experimentally investigated by measuring intensity auto- and cross-correlation functions. The experimental setup includes a moving crystal and an iCCD camera placed at the output plane of an imaging spectrometer. Evolution from the tight near-field spatial position cross-correlations to the far-field momentum cross-correlations, accompanied by changeless spectral cross-correlations, is observed. Intensity autocorrelation functions and beam profiles are also monitored as they provide the number of degrees of freedom constituting the down-converted beams. The strength of intensity cross-correlations as an alternative quantity for the determination of the number of degrees of freedom is also measured. The relation between the beam coherence and the number of degrees of freedom is discussed. PMID:26403609

  9. Apparatus and process for active pulse intensity control of laser beam

    DOEpatents

    Wilcox, Russell B.

    1992-01-01

    An optically controlled laser pulse energy control apparatus and process is disclosed wherein variations in the energy of a portion of the laser beam are used to vary the resistance of a photodetector such as a photoresistor through which a control voltage is fed to a light intensity controlling device through which a second portion of the laser beam passes. Light attenuation means are provided to vary the intensity of the laser light used to control the resistance of the photodetector. An optical delay path is provided through which the second portion of the beam travels before reaching the light intensity controlling device. The control voltage is supplied by a variable power supply. The apparatus may be tuned to properly attenuate the laser beam passing through the intensity controlling device by adjusting the power supply, the optical delay path, or the light attenuating means.

  10. Increase of the beam intensity for BNCT by changing the core configuration at THOR.

    PubMed

    Liu, H M; Peir, J J; Liu, Y H; Tsai, P E; Jiang, S H

    2009-07-01

    In this article, we will consider several core configurations and run the core calculation with MCNP to obtain the neutrons distribution at THOR. The thermal neutron flux inside the vertical tubes (VT-B-VT-E) and the fast neutron flux in the first row facing to the boron neutron capture therapy (BNCT) facility (I3-I5) were tallied for indication. Based on these simulation results, the fuel elements were rearranged during the annual repair period in 2007. The epithermal neutron flux at the center of BNCT beam exit in air was measured again, and the results showed that the beam intensity increased by 50%. Comparing the neutron intensities both in reactor core and at the BNCT beam exit for several core configurations, the results show that the BNCT beam intensity can be increased without decreasing the neutron intensity in core. PMID:19394237

  11. Evidence that the electrostatic ion cyclotron instability is saturated by ion heating. [in auroral arc

    NASA Technical Reports Server (NTRS)

    Kelley, M. C.; Bering, E. A.; Mozer, F. S.

    1975-01-01

    Observations have been made of electric field oscillations near the local ion gyro frequency and of an intense beam of plasma ions at the edge of an auroral arc. The observations are in good agreement with ion heating as the saturation mechanism for electrostatic ion cyclotron waves.

  12. A 3 Ghz photoelectron gun for high beam intensity

    SciTech Connect

    Bossart, R.; Braun, H.; Dehler, M.

    1995-12-31

    The CLIC Test Facility (CTF) for new accelerator structures of the proposed Compact Linear Collider (CLIC) is to be equipped with a new RF gun containing a laser driven photocathode. The new 3 GHz gun with photocathode shall produce a bunch train of 48 electron bunches of 25 nC charge each with a bunch length of 8 - 15 ps fwhm. The new RF gun consists of 2{1/2} cells and accelerates the beam to an energy of 7 MeV with a peak field gradient Ez = 100 MV/m. The strong space charge forces at low beam energy caused by the high charge density of the electron bunches must be contained by radial and longitudinal RF focusing in the RF gun. Radial RF focusing is applied by a conical backplane around the photocathode in the first cell where the electrons have a low energy. Longitudinal RF focusing is obtained by varying the length of each of the three cells of the gun. The total electric charge of the bunch train exceeds 1{mu}C and causes strong beam loading to the RF structures so that the stored energy is reduced to half of the unloaded RF energy. The RF gun under construction is being optimized by MAFIA beam simulations for an injector assembly comprising a second accelerating RF structure of 4 cells and an intermediate solenoid magnet correcting the beam divergence of the 2{1/2} cell gun. The scheme with two accelerating RF sections will provide a linear energy increase along the bunch suitable for further compression of the bunch length in a magnetic chicane.

  13. Designing Neutralized Drift Compression for Focusing of Intense Ion Beam Pulses in a Background Plasma

    SciTech Connect

    Kaganovich, I.D.; Davidson, R.C.; Dorf, M.; Startsev, E.A.; Barnard, J.J.; Friedman, A.; Lee, E.P.; Lidia, S.M.; Logan, B.G.; Roy, P.K.; Seidl, P.A.; Welch, D.R.; Sefkow, A.B.

    2009-04-28

    Neutralized drift compression offers an effective method for particle beam focusing and current amplification. In neutralized drift compression, a linear radial and longitudinal velocity drift is applied to a beam pulse, so that the beam pulse compresses as it drifts in the drift-compression section. The beam intensity can increase more than a factor of 100 in both the radial and longitudinal directions, resulting in more than 10,000 times increase in the beam number density during this process. The self-electric and self-magnetic fields can prevent tight ballistic focusing and have to be neutralized by supplying neutralizing electrons. This paper presents a survey of the present theoretical understanding of the drift compression process and plasma neutralization of intense particle beams. The optimal configuration of focusing and neutralizing elements is discussed in this paper.

  14. Optical apparatus using liquid crystals for shaping the spatial intensity of optical beams having designated wavelengths

    DOEpatents

    Jacobs, Stephen D.; Cerqua, Kathleen A.

    1987-01-01

    The spatial intensity profile of an optical beam of designated wavelengths, such as a laser beam, is shaped (the beam is apodized) by means of cholesteric liquid crystals of opposite chirality disposed successively along the path of the beam. The crystals have curved surfaces, which may be defined by a lens which defines the thickness of the liquid crystal fluid gap in a liquid crystal cell, so as to vary the selective reflection of the designated wavelength across the aperture of the beam. In this way, a soft aperture is provided. By using tandem cell pairs having liquid crystals of opposite chirality, but of different pitch, and with lenses of different curvature, beams of different wavelengths which are projected colinearly along the path may be individually tailored in spatial intensity profile.

  15. Transverse Beam Halo Measurements at High Intensity Neutrino Source (HINS) using Vibrating Wire Monitor

    SciTech Connect

    Chung, M.; Hanna, B.; Scarpine, V.; Shiltsev, V.; Steimel, J.; Artinian, S.; Arutunian, S.

    2015-02-26

    The measurement and control of beam halos will be critical for the applications of future high-intensity hadron linacs. In particular, beam profile monitors require a very high dynamic range when used for the transverse beam halo measurements. In this study, the Vibrating Wire Monitor (VWM) with aperture 60 mm was installed at the High Intensity Neutrino Source (HINS) front-end to measure the transverse beam halo. A vibrating wire is excited at its resonance frequency with the help of a magnetic feedback loop, and the vibrating and sensitive wires are connected through a balanced arm. The sensitive wire is moved into the beam halo region by a stepper motor controlled translational stage. We study the feasibility of the vibrating wire for the transverse beam halo measurements in the low-energy front-end of the proton linac.

  16. Optical apparatus using liquid crystals for shaping the spatial intensity of optical beams having designated wavelengths

    DOEpatents

    Jacobs, S.D.; Cerqua, K.A.

    1987-07-14

    The spatial intensity profile of an optical beam of designated wavelengths, such as a laser beam, is shaped (the beam is apodized) by means of cholesteric liquid crystals of opposite chirality disposed successively along the path of the beam. The crystals have curved surfaces, which may be defined by a lens which defines the thickness of the liquid crystal fluid gap in a liquid crystal cell, so as to vary the selective reflection of the designated wavelength across the aperture of the beam. In this way, a soft aperture is provided. By using tandem cell pairs having liquid crystals of opposite chirality, but of different pitch, and with lenses of different curvature, beams of different wavelengths which are projected colinearly along the path may be individually tailored in spatial intensity profile. 11 figs.

  17. The L3A facility at the Vinča Institute: Surface modification of materials, by heavy ion beams from an electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Dobrosavljević, A.; Milosavljević, M.; Bibić, N.; Efremov, A.

    2000-02-01

    This article describes the L3A experimental facility for surface modification of materials at the Vinča Institute of Nuclear Sciences, in Belgrade. This facility was completed and put into operation in May 1998. It is connected to the mVINIS ion source, an electron cyclotron resonance ion source capable of producing a wide range of multiply charged ions from gaseous and solid substances. The heavy ion beams obtained from mVINIS are separated by charge to mass ratio (q/m) and transported to the target chamber for sample irradiation and modification. The target chamber is equipped with a multipurpose target holder, an electron-beam evaporation source for thin layer deposition, a residual gas analyzer, and other auxiliary equipment. There is also an additional low energy argon ion source for target preparation/sputtering and for ion beam assisted deposition. In this article we describe the layout and performances of the L3A facility, the experience gained during 1 yr of operation, and the requirements imposed by the current and future experimental programs. Currently, there are 24 experimental programs competing for the ion beam time at the L3A facility.

  18. Production of intense negative hydrogen beams with polarized nuclei by selective neutralization of cold negative ions

    DOEpatents

    Hershcovitch, A.

    1984-02-13

    A process for selectively neutralizing H/sup -/ ions in a magnetic field to produce an intense negative hydrogen ion beam with spin polarized protons. Characteristic features of the process include providing a multi-ampere beam of H/sup -/ ions that are

  19. Device to color modulate a stationary light beam gives high intensity

    NASA Technical Reports Server (NTRS)

    Gantz, W. A.

    1966-01-01

    Signal controlled system color modulates a beam of light while also providing high intensity and a stationary beam, either collimated or focused. The color modulation acquired by the presented system can be compatible with any color film by employing color filters formed to provide a color wedge having a color distribution compatible with the films color sensitivity.

  20. Stabilization of signal beam intensity for fault-tolerant automatic routing with double phase conjugate mirrors

    NASA Astrophysics Data System (ADS)

    Kato, Hayato; Okamoto, Atsushi; Bunsen, Masatoshi

    2004-06-01

    We have proposed a fault-tolerant automatic routing method with two photorefractive double phase conjugate mirrors (DPCMs) for free space optical communication by now. In this method, a signal beam can be all-optically and automatically switched from a main line to a backup line when the main line is shut off by obstacles. The optical link between a transmitter and a receiver is kept without any electronic devices and complex optical configuration because the adequate communication line is automatically selected by two DPCMs which are generated by the signal beam and support beams in one photorefractive crystal. In this report, we equalize the signal beam intensities on the main line and the backup line to increase the reliability of communication. If a coupling strength ratio between two DPCMs is inappropriate, the signal beam intensities on both lines become inequality and this induces the increase of the bit error rate in beam detection. Therefore, it is necessary to adjust the signal beam intensities by changing the coupling strength ratio between two DPCMs. We show that the signal beam intensities on both lines can be equalized completely by using the optimum coupling strength ratio between two DPCMs, e.g. about 1.28 in BaTiO3 crystal.

  1. Production of multicharged radioactive ion beams: New results for the 1+-->n+ method with the MINIMAFIOS and SARA-CAPRICE electron cyclotron resonance ion sources

    NASA Astrophysics Data System (ADS)

    Lamy, T.; Bruandet, J.-F.; Chauvin, N.; Curdy, J.-C.; Fruneau, M.; Geller, R.; Gimond, G.; Sole, P.; Vieux-Rochas, J.-L.; Gaubert, G.; Maunoury, L.; Sortais, P.; Villari, A. C. C.

    1998-02-01

    The backward and forward injection of a 1+ ion beam in a MINIMAFIOS type electron cyclotron resonance ion source (ECRIS) have given good results for the 1+→n+ method. Due to the technological simplicity of the forward injection, additional experiments have been performed with this configuration. Different primary sources (1+) have been used for the injection (2.45 GHz ECRIS, hollow cathode source, simplified 10 GHz NANOGAN type ECRIS), an increase of the performances has already been obtained (Zn, Kr, Ar), and a measurement of the absolute efficiency with the NANOGAN type-MINIMAFIOS association is performed. Due to the high performance of the 10 GHz CAPRICE source used as a highly charged ion injector in the first cyclotron of SARA (Système Accélérateur Rhône-Alpes), it has been tested as a different n+ source for the 1+→n+ method. In this purpose, a low energy spread-low emittance thermoionization Rb ion source has been used as 1+ injector. A standard operation of the SARA-CAPRICE source has been kept with respect to the microwave coupling. The spectra of the Rbn+ ions extracted are compared when using N2 and O2 as support gases. The highest efficiency is obtained for the Rb13+.

  2. Production of multicharged radioactive ion beams: New results for the 1+-->n+ method with the MINIMAFIOS and SARA-CAPRICE electron cyclotron resonance ion sources

    NASA Astrophysics Data System (ADS)

    Lamy, T.; Bruandet, J.-F.; Chauvin, N.; Curdy, J.-C.; Fruneau, M.; Geller, R.; Gimond, G.; Sole, P.; Vieux-Rochas, J.-L.; Gaubert, G.; Maunoury, L.; Sortais, P.; Villari, A. C. C.

    1998-03-01

    The backward and forward injection of a 1+ ion beam in a MINIMAFIOS type electron cyclotron resonance ion source (ECRIS) have given good results for the 1+→n+ method. Due to the technological simplicity of the forward injection, additional experiments have been performed with this configuration. Different primary sources (1+) have been used for the injection (2.45 GHz ECRIS, hollow cathode source, simplified 10 GHz NANOGAN type ECRIS), an increase of the performances has already been obtained (Zn, Kr, Ar), and a measurement of the absolute efficiency with the NANOGAN type-MINIMAFIOS association is performed. Due to the high performance of the 10 GHz CAPRICE source used as a highly charged ion injector in the first cyclotron of SARA (Système Accélérateur Rhône-Alpes), it has been tested as a different n+ source for the 1+→n+ method. In this purpose, a low energy spread-low emittance thermoionization Rb ion source has been used as 1+ injector. A standard operation of the SARA-CAPRICE source has been kept with respect to the microwave coupling. The spectra of the Rbn+ ions extracted are compared when using N2 and O2 as support gases. The highest efficiency is obtained for the Rb13+.

  3. Space–time characterization of ultra-intense femtosecond laser beams

    NASA Astrophysics Data System (ADS)

    Pariente, G.; Gallet, V.; Borot, A.; Gobert, O.; Quéré, F.

    2016-08-01

    Femtosecond lasers can now deliver ultrahigh intensities at focus, making it possible to induce relativistic motion of charged particles with light and opening the way to new generations of compact particle accelerators and X-ray sources. With diameters of up to tens of centimetres, ultra-intense laser beams tend to suffer from spatiotemporal distortions, that is, a spatial dependence of their temporal properties that can dramatically reduce their peak intensities. At present, however, these intense electromagnetic fields are characterized and optimized in space and time separately. Here, we present the first complete spatiotemporal experimental reconstruction of the field E(t,r) for a 100 TW peak-power laser, and reveal the spatiotemporal distortions that can affect such beams. This new measurement capability opens the way to in-depth characterization and optimization of ultra-intense lasers and ultimately to the advanced control of relativistic motion of matter with femtosecond laser beams structured in space–time.

  4. Experimental study of magnetically confined hollow electron beams in the Tevatron as collimators for intense high-energy hadron beams

    SciTech Connect

    Stancari, G.; Annala, G.; Shiltsev, V.; Still, D.; Valishev, A.; Vorobiev, L.; /Fermilab

    2011-03-01

    Magnetically confined hollow electron beams for controlled halo removal in high-energy colliders such as the Tevatron or the LHC may extend traditional collimation systems beyond the intensity limits imposed by tolerable losses. They may also improve collimation performance by suppressing loss spikes due to beam jitter and by increasing capture efficiency. A hollow electron gun was designed and tested at Fermilab for this purpose. It was installed in one of the Tevatron electron lenses in the summer of 2010. We present the results of the first experimental tests of the hollow-beam collimation concept on 980-GeV antiproton bunches in the Tevatron.

  5. Implications of the Electrostatic Approximation in the Beam Frame on the Nonlinear Vlasov-Maxwell Equations for Intense Beam Propagation

    SciTech Connect

    Ronald C. Davidson; W. Wei-li Lee; Hong Qin; Edward Startsev

    2001-11-08

    This paper develops a clear procedure for solving the nonlinear Vlasov-Maxwell equations for a one-component intense charged particle beam or finite-length charge bunch propagating through a cylindrical conducting pipe (radius r = r(subscript)w = const.), and confined by an applied focusing force. In particular, the nonlinear Vlasov-Maxwell equations are Lorentz-transformed to the beam frame ('primed' variables) moving with axial velocity relative to the laboratory. In the beam frame, the particle motions are nonrelativistic for the applications of practical interest, already a major simplification. Then, in the beam frame, we make the electrostatic approximation which fully incorporates beam space-charge effects, but neglects any fast electromagnetic processes with transverse polarization (e.g., light waves). The resulting Vlasov-Maxwell equations are then Lorentz-transformed back to the laboratory frame, and properties of the self-generated fields and resulting nonlinear Vlasov-Maxwell equations in the laboratory frame are discussed.

  6. Effect of angular spread on the intensity distribution of arbitrarily shaped electron beams

    SciTech Connect

    Mohan, R.; Chui, C.S.; Fontenla, D.; Han, K.; Ballon, D.

    1988-03-01

    Knowledge of the relative intensity distribution at the patient's surface is essential for pencil beam calculations of three-dimensional dose distributions for arbitrarily shaped electron beams. To calculate the relative intensity distribution, the spatial spread resulting from angular spread is convolved with a two-dimensional step function whose shape corresponds to the applicator aperture. Two different approaches to obtain angular spread or the equivalent spatial spread are investigated. In the first method, the pencil beam angular spread is assumed to be Gaussian in shape. The angular spread constants (sigma theta) are then obtained from the slopes of measured intensity profiles. In the second method, the angular spread, in the form of an array of numerical values, is obtained by the deconvolution of measured intensity profiles. After obtaining the angular spread, the calculation for convolution is done in a number of parallel planes normal to the central axis at various distances from the electron collimator. Intensity at any arbitrary point in space is computed by interpolating between intensity distributions in adjacent planes on either side of the point. The effects of variations in angular spread as a function of field size for two treatment machines, one with a scanned electron beam and the other with a scattering foil, have been studied. The consequences of assuming angular spread to be of Gaussian shape are also examined. The electron intensity calculation techniques described in this paper apply primarily to methods of dose calculations that employ pencil beams generated using Monte Carlo simulations.

  7. Intensity Effects of the FACET Beam in the SLAC Linac

    SciTech Connect

    Decker, F.-J.; Lipkowitz, N.; Sheppard, J.; White, G.R.; Wienands, U.; Woodley, M.; Yocky, G.; /SLAC

    2012-07-03

    The beam for FACET (Facility for Advanced aCcelerator Experimental Tests) at SLAC requires an energy-time correlation ('chirp') along the linac, so it can be compressed in two chicanes, one at the midpoint in sector 10 and one W-shaped chicane just before the FACET experimental area. The induced correlation has the opposite sign to the typical used for BNS damping, and therefore any orbit variations away from the center kick the tail of the beam more than the head, causing a shear in the beam and emittance growth. Any dispersion created along the linac has similar effects due to the high (>1.2% rms) energy spread necessary for compression. The initial huge emittances could be reduced by a factor of 10, but were still bigger than expected by a factor of 2-3. Normalized emittance of 3 {micro}m-rad in Sector 2 blew up to 150 {micro}m-rad in Sector 11 but could be reduced to about 6-12 {micro}m-rad, for the vertical plane although the results were not very stable. Investigating possible root causes for this, we found locations where up to 10 mm dispersion was created along the linac, which were finally verified with strong steering and up to 7 mm settling of the linac accelerator at these locations.

  8. Electron cyclotron resonance plasma source by using Ku-band traveling-wave tube amplifier for broad ion-beam processing

    NASA Astrophysics Data System (ADS)

    Asaji, Toyohisa; Sasaki, Hiroshi; Kato, Yushi; Sato, Fuminobu; Iida, Toshiyuki; Saito, Junji

    2006-03-01

    A new electron cyclotron resonance (ECR) plasma source has been developed for broad ion-beam processing. A Ku-band traveling-wave tube amplifier (11-13GHz) is adopted to generate high-density plasma under low-pressure conditions. An eight-pole magnetic field is selected to improve good uniformity and plasma confinement. The ECR zone for 11GHz microwaves, i.e., 0.393T, is formed within 6.5mm of the inner wall of a chamber. The ECR plasma is generated by low microwave power (˜200W). The radial profile of plasma density and electron temperature is measured with a Langmuir probe. The plasma density is approximately 3×1017m-3 at the microwave power of 200W. The uniformity of the density is within ±12.6% over 140mm in diameter.

  9. Deuterium beam acceleration with 3rd harmonic ion cyclotron resonance heating in Joint European Torus: Sawtooth stabilization and Alfvén eigenmodes

    NASA Astrophysics Data System (ADS)

    Gassner, T.; Schoepf, K.; Sharapov, S. E.; Kiptily, V. G.; Pinches, S. D.; Hellesen, C.; Eriksson, J.; JET-EFDA contributors

    2012-03-01

    Experiments on accelerating NBI-produced deuterium (D) beam ions from their injection energy of ˜110 keV up to the MeV energy range with 3rd harmonic ion cyclotron resonance heating were performed on the Joint European Torus [P. H. Rebut and B. E. Keen, Fusion Technol. 11, 13 (1987)]. A renewed set of nuclear diagnostics was used for analysing fast D ions during sawtooth stabilization, monster sawtooth crashes, and during excitation of Alfvén eigenmodes (AEs) residing inside the q = 1 radius. The measurements and modeling of the fast ions with the nonlinear HAGIS code [S. D. Pinches et al., Comput. Phys. Commun. 111, 133 (1998)] show that monster sawtooth crashes are strongly facilitated by the AE-induced re-distribution of the fast D ions from inside the q = 1 radius to the plasma edge.

  10. Dependence of ion beam current on position of mobile plate tuner in multi-frequencies microwaves electron cyclotron resonance ion source.

    PubMed

    Kurisu, Yosuke; Kiriyama, Ryutaro; Takenaka, Tomoya; Nozaki, Dai; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

    2012-02-01

    We are constructing a tandem-type electron cyclotron resonance ion source (ECRIS). The first stage of this can supply 2.45 GHz and 11-13 GHz microwaves to plasma chamber individually and simultaneously. We optimize the beam current I(FC) by the mobile plate tuner. The I(FC) is affected by the position of the mobile plate tuner in the chamber as like a circular cavity resonator. We aim to clarify the relation between the I(FC) and the ion saturation current in the ECRIS against the position of the mobile plate tuner. We obtained the result that the variation of the plasma density contributes largely to the variation of the I(FC) when we change the position of the mobile plate tuner. PMID:22380157

  11. Structure and morphology characters of GaN grown by ECR-MBE using hydrogen-nitrogen mixed gas plasma[Electron Cyclotron Resonance-Molecular Beam Epitaxy

    SciTech Connect

    Araki, Tsutomu; Chiba, Yasuo; Nanishi, Yasushi

    2000-07-01

    GaN growth by electron-cyclotron-resonance plasma-excited molecular beam epitaxy using hydrogen-nitrogen mixed gas plasma were carried out on GaN templates with a different polar-surface. Structure and surface morphology of the GaN layers were characterized using transmission electron microscopy. The GaN layer grown with hydrogen on N-polar template showed a relatively flat morphology including hillocks. Columnar domain existed in the center of the hillock, which might be attributed to the existence of tiny inversion domain with Ga-polarity. On the other hand, columnar structure was formed in the GaN layer grown with hydrogen on Ga-polar template.

  12. Dependence of ion beam current on position of mobile plate tuner in multi-frequencies microwaves electron cyclotron resonance ion source

    SciTech Connect

    Kurisu, Yosuke; Kiriyama, Ryutaro; Takenaka, Tomoya; Nozaki, Dai; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

    2012-02-15

    We are constructing a tandem-type electron cyclotron resonance ion source (ECRIS). The first stage of this can supply 2.45 GHz and 11-13 GHz microwaves to plasma chamber individually and simultaneously. We optimize the beam current I{sub FC} by the mobile plate tuner. The I{sub FC} is affected by the position of the mobile plate tuner in the chamber as like a circular cavity resonator. We aim to clarify the relation between the I{sub FC} and the ion saturation current in the ECRIS against the position of the mobile plate tuner. We obtained the result that the variation of the plasma density contributes largely to the variation of the I{sub FC} when we change the position of the mobile plate tuner.

  13. Emittance growth of an nonequilibrium intense electron beam in a transport channel with discrete focusing

    SciTech Connect

    Carlsten, B.E.

    1997-02-01

    The author analyzes the emittance growth mechanisms for a continuous, intense electron beam in a focusing transport channel, over distances short enough that the beam does not reach equilibrium. The emittance grows from the effect of nonlinear forces arising from (1) current density nonuniformities, (2) energy variations leading to nonlinearities in the space-charge force even if the current density is uniform, (3) axial variations in the radial vector potential, (4) an axial velocity shear along the beam, and (5) an energy redistribution of the beam as the beam compresses or expands. The emittance growth is studied analytically and numerically for the cases of balanced flow, tight focusing, and slight beam scalloping, and is additionally studied numerically for an existing 6-MeV induction linear accelerator. Rules for minimizing the emittance along a beamline are established. Some emittance growth will always occur, both from current density nonuniformities that arise along the transport and from beam radius changes along the transport.

  14. RF control hardware design for CYCIAE-100 cyclotron

    NASA Astrophysics Data System (ADS)

    Yin, Zhiguo; Fu, Xiaoliang; Ji, Bin; Zhao, Zhenlu; Zhang, Tianjue; Li, Pengzhan; Wei, Junyi; Xing, Jiansheng; Wang, Chuan

    2015-11-01

    The Beijing Radioactive Ion-beam Facility project is being constructed by BRIF division of China Institute of Atomic Energy. In this project, a 100 MeV high intensity compact proton cyclotron is built for multiple applications. The first successful beam extraction of CYCIAE-100 cyclotron was done in the middle of 2014. The extracted proton beam energy is 100 MeV and the beam current is more than 20 μA. The RF system of the CYCIAE-100 cyclotron includes two half-wavelength cavities, two 100 kW tetrode amplifiers and power transmission line systems (all above are independent from each other) and two sets of Low Level RF control crates. Each set of LLRF control includes an amplitude control unit, a tuning control unit, a phase control unit, a local Digital Signal Process control unit and an Advanced RISC Machines based EPICS IOC unit. These two identical LLRF control crates share one common reference clock and take advantages of modern digital technologies (e.g. DSP and Direct Digital Synthesizer) to achieve closed loop voltage and phase regulations of the dee-voltage. In the beam commission, the measured dee-voltage stability of RF system is better than 0.1% and phase stability is better than 0.03°. The hardware design of the LLRF system will be reviewed in this paper.

  15. Combined infrared multiphoton dissociation and electron capture dissociation with a hollow electron beam in Fourier transform ion cyclotron resonance mass spectrometry.

    PubMed

    Tsybin, Youri O; Witt, Matthias; Baykut, Gökhan; Kjeldsen, Frank; Håkansson, Per

    2003-01-01

    An electron injection system based on an indirectly heated ring-shaped dispenser cathode has been developed and installed in a 7 Tesla Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. This new hardware design allows high-rate electron capture dissociation (ECD) to be carried out by a hollow electron beam coaxial with the ion cyclotron resonance (ICR) trap. Infrared multiphoton dissociation (IRMPD) can also be performed with an on-axis IR-laser beam passing through a hole at the centre of the dispenser cathode. Electron and photon irradiation times of the order of 100 ms are required for efficient ECD and IRMPD, respectively. As ECD and IRMPD generate fragments of different types (mostly c, z and b, y, respectively), complementary structural information that improves the characterization of peptides and proteins by FTICR mass spectrometry can be obtained. The developed technique enables the consecutive or simultaneous use of the ECD and IRMPD methods within a single FTICR experimental sequence and on the same ensemble of trapped ions in multistage tandem (MS/MS/MS or MS(n)) mass spectrometry. Flexible changing between ECD and IRMPD should present advantages for the analysis of protein digests separated by liquid chromatography prior to FTICRMS. Furthermore, ion activation by either electron or laser irradiation prior to, as well as after, dissociation by IRMPD or ECD increases the efficiency of ion fragmentation, including the w-type fragment ion formation, and improves sequencing of peptides with multiple disulfide bridges. The developed instrumental configuration is essential for combined ECD and IRMPD on FTICR mass spectrometers with limited access into the ICR trap. PMID:12872281

  16. Scanning beam switch experiment for intense rf power generation

    NASA Astrophysics Data System (ADS)

    Humphries, Stanley, Jr.; Babcock, Steven R.; Wilson, J. M.; Adler, Richard J.

    1991-04-01

    1407_57The SBS_1 experiment at Sandia National Laboratories is designed to demonstrate the feasibility of the Scanning Beam Switch for high-power rf generation. The primary application is to pulsed rf linacs and high-frequency induction accelerators. It is expected that the apparatus will generate rf output power exceeding 100 MW at 50 MHz over a 5 microsecond(s) pulse. The device can operate as an oscillator or high gain amplifier. To achieve the capability for long-macropulse and high-duty-cycle operation, SBS_1 uses a large dispenser cathode and vacuum triode input driver.

  17. Laboratory Astrophysics Using High Intensity Particle and Photon Beams

    SciTech Connect

    Chen, Pisin

    2001-12-12

    History has shown that the symbiosis between direct observations and laboratory studies is instrumental in the progress of astrophysics. Recent years have seen growing interests in the laboratory investigation of astrophysical phenomena that can be addressed by high densities and advancement of technologies in lasers as well as high-energy particle beams. We will give examples on how frontier phenomena such as black holes, supernovae, gamma ray bursts, ultra high-energy cosmic rays, etc., can be investigated in the laboratory setting. Finally, we describe a possible laboratory astrophysics facility to be developed at SLAC.

  18. Laboratory Astrophysics Using High Intensity Particle and Photon Beams

    SciTech Connect

    Chen, Pisin

    2009-12-12

    History has shown that the symbiosis between direct observations and laboratory studies is instrumental in the progress of astrophysics. Recent years have seen growing interests in the laboratory investigation of astrophysical phenomena that can be addressed by high densities and advancement of technologies in lasers as well as high-energy particle beams. We will give examples on how frontier phenomena such as black holes, supernovae, gamma ray bursts, ultra high-energy cosmic rays, etc., can be investigated in the laboratory setting. Finally, we describe a possible laboratory astrophysics facility to be developed at SLAC.

  19. Quantification of beam complexity in intensity-modulated radiation therapy treatment plans

    SciTech Connect

    Du, Weiliang Cho, Sang Hyun; Zhang, Xiaodong; Kudchadker, Rajat J.; Hoffman, Karen E.

    2014-02-15

    Purpose: Excessive complexity in intensity-modulated radiation therapy (IMRT) plans increases the dose uncertainty, prolongs the treatment time, and increases the susceptibility to changes in patient or target geometry. To date, the tools for quantitative assessment of IMRT beam complexity are still lacking. In this study, The authors have sought to develop metrics to characterize different aspects of beam complexity and investigate the beam complexity for IMRT plans of different disease sites. Methods: The authors evaluated the beam complexity scores for 65 step-and-shoot IMRT plans from three sites (prostate, head and neck, and spine) and 26 volumetric-modulated arc therapy (VMAT) plans for the prostate. On the basis of the beam apertures and monitor unit weights of all segments, the authors calculated the mean aperture area, extent of aperture shape irregularity, and degree of beam modulation for each beam. Then the beam complexity values were averaged to obtain the complexity metrics of the IMRT plans. The authors studied the correlation between the beam complexity metrics and the quality assurance (QA) results. Finally, the effects of treatment planning parameters on beam complexity were studied. Results: The beam complexity scores were not uniform among the prostate IMRT beams from different gantry angles. The lateral beams had larger monitor units and smaller shape irregularity, while the anterior-posterior beams had larger modulation values. On average, the prostate IMRT plans had the smallest aperture irregularity, beam modulation, and normalized monitor units; the head and neck IMRT plans had large beam irregularity and beam modulation; and the spine stereotactic radiation therapy plans often had small beam apertures, which may have been associated with the relatively large discrepancies between planned and QA measured doses. There were weak correlations between the beam complexity scores and the measured dose errors. The prostate VMAT beams showed

  20. Estimation of photoneutron intensities around radiotherapy linear accelerator 23-MV photon beam.

    PubMed

    Shweikani, R; Anjak, O

    2015-05-01

    CR-39 solid-state nuclear track detectors (SSNTDs) were used to study the variations of fast neutron relative intensities around a high-energy (23MV) linear accelerator (Varian 21EX) photon beam. The variations were determined on the patient plane at 0, 50, 100, 150 and 200cm from the isocenter of the photon beam. In addition, photoneutron intensities and distributions at isocenter level with field size of 40×40cm(2) at Source Axis Distance (SAD)=100cm around 23MV photon beam were also determined. The results showed that the photoneutron intensities decreased rapidly by increasing the distance from the center of the x-ray beam towards the periphery, for the open fields. PMID:25770858

  1. Slant path average intensity of finite optical beam propagating in turbulent atmosphere

    NASA Astrophysics Data System (ADS)

    Zhang, Yixin; Wang, Gaogang

    2006-10-01

    The average intensity of finite laser beam propagating through turbulent atmosphere is calculated from the extended Huygens Fresnel principle. Formulas are presented for the slant path average intensity from an arbitrarily truncated Gaussian beam. The new expressions are derived from the modified von Karman spectrum for refractive-index fluctuations, quadratic approximation of the structure function, and Gaussian approximation for the product of Gaussian function and Bessel function. It is shown that the form of average intensity is not a Gaussian function but a polynomial of the power of the binomial function, Gaussian function, and the incomplete gamma function. The results also show that the mean irradiance of a finite optical beam propagating in slant path turbulent atmosphere not only depends on the effective beam radius at the transmitting aperture plane, propagation distance, and long-term lateral coherence length of spherical wave, but also on the radius of emit aperture.

  2. EBIS/T charge breeding for intense rare isotope beams at MSU

    SciTech Connect

    Schwarz, S.; Bollen, Georg; Kester, O.; Kittimanapun, K.; Lapierre, A.; Lopez-Urrutia, J. R. Crespo; Dilling, J.; Ames, F.; Ahle, Larry; Beiersdorfer, P.; Marrs, R. E.; Beene, James R; Mendez, II, Anthony J; Stracener, Daniel W; Lindroos, M.; Wenander, F.

    2010-01-01

    Experiments with reaccelerated beams are an essential component of the science program of existing and future rare isotope beam facilities. NSCL is currently constructing ReA3, a reaccelerator for rare isotopes that have been produced by projectile fragmentation and in-flight fission and that have been thermalized in a gas stopper. The resulting low-energy beam will be brought to an Electron Beam Ion Source/Trap (EBIS/T) in order to obtain highly charged ions at an energy of 12 keV/u. This charge breeder is followed by a compact linear accelerator with a maximum beam energy of 3MeV/u for U-238 and higher energies for lighter isotopes. Next-generation rare isotope beam facilities like the Facility for Rare Isotope Beams FRIB, but also existing Isotope Separator On-line (ISOL) facilities are expected to provide rare-isotope beam rates in the order of 10(11) particles per second for reacceleration. At present the most promising scheme to efficiently start the reacceleration of these intense beams is the use of a next-generation high-current charge-breeder based on an EBIS/T. MSU has formed a collaboration to develop an EBIT for this purpose. A new high-current EBIS/T breeder will be developed and constructed at MSU, where also first tests on achievable beam rate capability will be performed. The EBIT is planned to be installed at the Isotope Separator and Accelerator facility ISAC at TRIUMF laboratory for on-line tests with rare isotope beams and to provide intense energetic reaccelerated radioactive beams. The status of the ReA3-EBIS/T in the NSCL reaccelerator project is given with a brief summary of results, followed by a discussion of plans for the future high-intensity EBIS/T charge breeder.

  3. Design features and performance of the LAMPF high-intensity beam area

    SciTech Connect

    Agnew, L.; Grisham, D.; Macek, R.J.; Sommer, W.F.; Werbeck, R.D.

    1983-01-01

    LAMPF is a multi-purpose high-intensity meson factory capable of producing a 1 mA beam of 800-MeV protons. The three target cells and the beam stop facilities in the high intensity area have many special design features that are required for operation in the presence of high heat loads and intense radiation fields where accessibility is extremely limited. Reliable targets, beam windows, beam stops, beam transport and diagnostic components, vacuum enclosures, and auxiliary systems have been developed. Sophisticated remote-handling systems are employed for maintenance. Complex protection systems have been developed to guard against damage caused by errant beam. Beam availability approaching 90% has been achieved at currents of 600 to 700 ..mu..A. A new facility for direct proton and neutron radiation effects studies will be installed in 1985. The new facility will provide an integrated spallation neutron flux of up to 5 x 10/sup 17/ m/sup -2/s/sup -1/ and will anable proton irradiation studies in the primary beam.

  4. Correction of linear-array lidar intensity data using an optimal beam shaping approach

    NASA Astrophysics Data System (ADS)

    Xu, Fan; Wang, Yuanqing; Yang, Xingyu; Zhang, Bingqing; Li, Fenfang

    2016-08-01

    The linear-array lidar has been recently developed and applied for its superiority of vertically non-scanning, large field of view, high sensitivity and high precision. The beam shaper is the key component for the linear-array detection. However, the traditional beam shaping approaches can hardly satisfy our requirement for obtaining unbiased and complete backscattered intensity data. The required beam distribution should roughly be oblate U-shaped rather than Gaussian or uniform. Thus, an optimal beam shaping approach is proposed in this paper. By employing a pair of conical lenses and a cylindrical lens behind the beam expander, the expanded Gaussian laser was shaped to a line-shaped beam whose intensity distribution is more consistent with the required distribution. To provide a better fit to the requirement, off-axis method is adopted. The design of the optimal beam shaping module is mathematically explained and the experimental verification of the module performance is also presented in this paper. The experimental results indicate that the optimal beam shaping approach can effectively correct the intensity image and provide ~30% gain of detection area over traditional approach, thus improving the imaging quality of linear-array lidar.

  5. The intensity distribution of hollow Gaussian beams focused by a lens with spherical aberration

    NASA Astrophysics Data System (ADS)

    Alkelly, Abdu A.; Al-Nadary, H.; Alhijry, Ibraheem A.

    2011-01-01

    We developed an expression that describes the hollow Gaussian beams (HGBs) passing through a spherically aberrated lens by using the Collins formula. The radial intensity distribution in both spherical aberration SA free lens, lens that exhibits relatively large in both positive spherical aberration PSA, and negative spherical aberration NSA is calculated. Numerical calculations are made and the results show that the PSA and NSA have a strong influence on the intensity distribution especially at the focus. The study showed remarkable results for which there is no hollow Gaussian beam at a large NSA along the optical axis at the focus. In addition, we found that the DSS, and wr of focused hollow Gaussian beams in the focal region depend not only on the beam radius, and beam order; but also on the spherical aberration.

  6. Cryogenic gas target system for intense RI beam productions in nuclear astrophysics

    SciTech Connect

    Wakabayashi, Y.; Yamaguchi, H.; Hayakawa, S.; Kurihara, Y.; Amadio, G.; Fujikawa, H.; Kubono, S.; Binh, D. N.; He, J. J.; Kim, A.

    2008-05-21

    A cryogenic gas target system was newly developed to produce intense RI beams at the low-energy in-flight radio-isotope beam separator (CRIB) of the University of Tokyo. The main features of the cryogenic gas target system are the direct cooling of the target cell by a liquid N{sub 2} finger and the circulation of the target gas that goes through the liquid N{sub 2} tank. Hydrogen gas was cooled down to 85-90 K by liquid nitrogen and used as a secondary beam production target which has a thickness of 2.3 mg/cm{sup 2} at the gas pressure of 760 Torr. Intense RI beams, such as a {sup 7}Be beam of 2x10{sup 8} particles per second, were successfully produced using the target.

  7. Simulation of electron behavior in PIG ion source for 9 MeV cyclotron

    NASA Astrophysics Data System (ADS)

    J. Mu, X.; Ghergherehchi, M.; H. Yeon, Y.; W. Kim, J.; S. Chai, J.

    2014-12-01

    In this paper, we focus on a PIG source for producing intense H-ions inside a 9 MeV cyclotron. The properties of the PIG ion source were simulated for a variety of electric field distributions and magnetic field strengths using a CST particle studio. After analyzing the secondary electron emission (SEE) as a function of both magnetic and electric field strengths, we found that for the modeled PIG geometry, a magnetic field strength of 0.2 T provided the best results in terms of the number of secondary electrons. Furthermore, at 0.2 T, the number of secondary electrons proved to be greatest regardless of the cathode potential. Also, the modified PIG ion source with quartz insulation tubes was tested in a KIRAMS-13 cyclotron by varying the gas flow rate and arc current, respectively. The capacity of the designed ion source was also demonstrated by producing plasma inside the constructed 9 MeV cyclotron. As a result, the ion source is verified as being capable of producing an intense H- beam and high ion beam current for the desired 9 MeV cyclotron. The simulation results provide experimental constraints for optimizing the strength of the plasma and final ion beam current at a target inside a cyclotron.

  8. A beam intensity monitor for the Loma Linda cancer therapy proton accelerator

    SciTech Connect

    Coutrakon, G.; Miller, D. ); Kross, B.J.; Anderson, D.F. ); DeLuca, P. Jr.; Siebers, J. )

    1991-07-01

    A beam intensity monitor was tested in a 230-MeV proton beam at the Loma Linda Proton Therapy Accelerator during its commissioning at Fermi National Accelerator Laboratory. The intensity monitor was designed to regulate the beam intensity extracted from the proton synchrotron. The proton beam is tunable between 70 and 250 MeV with an adjustable intensity between 10{sup 10} and 10{sup 11} protons per spill. A beam spill is typically 1 s long with a 2-s repetition period. The intensity monitor must be radiation hard, expose minimum mass to the beam, and measure intensity to 1% in 1-ms time intervals. To this end, a 5-cm-thick xenon gas scintillator optically coupled to a photomultiplier tube (PMT) was tested to measure its response to the proton beam. The gas cell was operated at 1.2 atm of pressure and has 12.7-{mu}m-thick titanium entrance and exit foils. The total mass exposed to the beam is 0.14 g/cm{sup 2} and is dominated by the titanium windows. This mass corresponds to a range attenuation equal to 1.4 mm of water. The energy lost to the xenon gas is about 70 keV per proton. Each passing proton will produce approximately 2000 photons. With a detection efficiency on the order of 0.05% for this UV light, one would anticipate over 10{sup 10} photoelectrons per second. In a 1-ms time bin there will be approximately 10{sup 7} photoelectrons. This yields a resolution limited by systematics. For unregulated 0.4-s proton spills, we observe a response bandwidth in excess of 10{sup 4} Hz. While signal-to-noise and linearity were not easily measured, we estimate as few as 10{sup 3} protons can be observed suggesting a dynamic range in excess of 10{sup 5} is available.

  9. A beam intensity monitor for the Loma Linda cancer therapy proton accelerator.

    PubMed

    Coutrakon, G; Miller, D; Kross, B J; Anderson, D F; DeLuca, P; Siebers, J

    1991-01-01

    A beam intensity monitor was tested in a 230-MeV proton beam at the Loma Linda Proton Therapy Accelerator during its commissioning at Fermi National Accelerator Laboratory. The intensity monitor was designed to regulate the beam intensity extracted from the proton synchrotron. The proton beam is tunable between 70 and 250 MeV with an adjustable intensity between 10(10) and 10(11) protons per spill. A beam spill is typically 1 s long with a 2-s repetition period. The intensity monitor must be radiation hard, expose minimum mass to the beam, and measure intensity to 1% in 1-ms time intervals. To this end, a 5-cm-thick xenon gas scintillator optically coupled to a photomultiplier tube (PMT) was tested to measure its response to the proton beam. The gas cell was operated at 1.2 atm of pressure and has 12.7-microns-thick titanium entrance and exit foils. The total mass exposed to the beam is 0.14 g/cm2 and is dominated by the titanium windows. This mass corresponds to a range attenuation equal to 1.4 mm of water. The energy lost to the xenon gas is about 70 keV per proton. Each passing proton will produce approximately 2000 photons. With a detection efficiency on the order of 0.05% for this UV light, one would anticipate over 10(10) photoelectrons per second. In a 1-ms time bin there will be approximately 10(7) photoelectrons. This yields a resolution limited by systematics. For unregulated 0.4-s proton spills, we observe a response bandwidth in excess of 10(4) Hz. While signal-to-noise and linearity were not easily measured, we estimate as few as 10(3) protons can be observed suggesting a dynamic range in excess of 10(5) is available. PMID:1656180

  10. Density and potential measurements in an intense ion-beam-generated plasma

    SciTech Connect

    Abt, N.E.

    1982-05-01

    Neutral beams are created by intense large area ion beams which are neutralized in a gas cell. The interaction of the beam with the gas cell creates a plasma. Such a plasma is studied here. The basic plasma parameters, electron temperature, density, and plasma potential, are measured as a function of beam current and neutral gas pressure. These measurements are compared to a model based on the solution of Poisson's equation. Because of the cylindrical geometry the equation cannot be solved analytically. Details of the numerical method are presented.

  11. Core-halo limit and internal dynamics of high intensity beams

    SciTech Connect

    Nghiem, P. A. P.; Valette, M.; Chauvin, N.; Pichoff, N.; Uriot, D.

    2015-08-15

    The dynamics of high-intensity beams largely depends on their internal space charge forces. These forces are responsible of non-linear coupling, emittance growth, and halo generation. They contribute to shape the beam density profile. As a consequence, an analysis of this profile can be a precious indicator capable of revealing the internal dynamics of the beam. This paper recalls the precise core-halo limit determination proposed earlier, then studies its behavior through a wide range of beam profiles, and finally shows its relevance as an indicator of the limit separating the two space charge field regimes of the core and the halo.

  12. Results of RIKEN superconducting electron cyclotron resonance ion source with 28 GHz.

    PubMed

    Higurashi, Y; Ohnishi, J; Nakagawa, T; Haba, H; Tamura, M; Aihara, T; Fujimaki, M; Komiyama, M; Uchiyama, A; Kamigaito, O

    2012-02-01

    We measured the beam intensity of highly charged heavy ions and x-ray heat load for RIKEN superconducting electron cyclotron resonance ion source with 28 GHz microwaves under the various conditions. The beam intensity of Xe(20+) became maximum at B(min) ∼ 0.65 T, which was ∼65% of the magnetic field strength of electron cyclotron resonance (B(ECR)) for 28 GHz microwaves. We observed that the heat load of x-ray increased with decreasing gas pressure and field gradient at resonance zone. It seems that the beam intensity of highly charged heavy ions with 28 GHz is higher than that with 18 GHz at same RF power. PMID:22380155

  13. Method and apparatus for measuring the momentum, energy, power, and power density profile of intense particle beams

    DOEpatents

    Gammel, George M.; Kugel, Henry W.

    1992-10-06

    A method and apparatus for determining the power, momentum, energy, and power density profile of high momentum mass flow. Small probe projectiles of appropriate size, shape and composition are propelled through an intense particle beam at equal intervals along an axis perpendicular to the beam direction. Probe projectiles are deflected by collisions with beam particles. The net beam-induced deflection of each projectile is measured after it passes through the intense particle beam into an array of suitable detectors.

  14. Spherical cluster analysis for beam angle optimization in intensity-modulated radiation therapy treatment planning

    NASA Astrophysics Data System (ADS)

    Bangert, Mark; Oelfke, Uwe

    2010-10-01

    An intuitive heuristic to establish beam configurations for intensity-modulated radiation therapy is introduced as an extension of beam ensemble selection strategies applying scalar scoring functions. It is validated by treatment plan comparisons for three intra-cranial, pancreas, and prostate cases each. Based on a patient specific matrix listing the radiological quality of candidate beam directions individually for every target voxel, a set of locally ideal beam angles is generated. The spherical distribution of locally ideal beam angles is characteristic for every treatment site and patient: ideal beam angles typically cluster around distinct orientations. We interpret the cluster centroids, which are identified with a spherical K-means algorithm, as irradiation angles of an intensity-modulated radiation therapy treatment plan. The fluence profiles are subsequently optimized during a conventional inverse planning process. The average computation time for the pre-optimization of a beam ensemble is six minutes on a state-of-the-art work station. The treatment planning study demonstrates the potential benefit of the proposed beam angle optimization strategy. For the three prostate cases under investigation, the standard treatment plans applying nine coplanar equi-spaced beams and treatment plans applying an optimized non-coplanar nine-beam ensemble yield clinically comparable dose distributions. For symmetric patient geometries, the dose distribution formed by nine equi-spaced coplanar beams cannot be improved significantly. For the three pancreas and intra-cranial cases under investigation, the optimized non-coplanar beam ensembles enable better sparing of organs at risk while guaranteeing equivalent target coverage. Beam angle optimization by spherical cluster analysis shows the biggest impact for target volumes located asymmetrically within the patient and close to organs at risk.

  15. Phase-contrast tomography with low-intensity beams

    SciTech Connect

    Rehacek, J.; Hradil, Z.; Zawisky, M.; Dubus, F.; Bonse, U.

    2005-02-01

    In newly developed neutron phase tomography, wave properties of neutrons are exploited for the nondestructive testing of the internal structure of matter. We show how limitations due to small available intensities of present neutron sources can be overcome by using an advanced maximum-likelihood reconstruction algorithm. Unlike the standard filtered back-projection, the developed procedure gives reasonable results also when used on very noisy data or data consisting of only a few measured projections. This is demonstrated by means of simulations and also experimentally. The proposed method leads to considerably shorter measuring times and/or increased precision.

  16. First charge breeding of a rare-isotope beam with the electron-beam ion trap of the ReA post-accelerator at the National Superconducting Cyclotron Laboratory

    NASA Astrophysics Data System (ADS)

    Lapierre, A.; Schwarz, S.; Baumann, T. M.; Cooper, K.; Kittimanapun, K.; Rodriguez, A. J.; Sumithrarachchi, C.; Williams, S. J.; Wittmer, W.; Leitner, D.; Bollen, G.

    2014-02-01

    An electron-beam ion trap (EBIT) charge breeder is being brought into operation at the National Superconducting Cyclotron Laboratory at Michigan State University. The EBIT is part of the ReA post-accelerator for reacceleration of rare isotopes, which are thermalized in a gas "stopping" cell after being produced at high energy by projectile fragmentation. The ReA EBIT has a distinctive design; it is characterized by a high-current electron gun and a two-field superconducting magnet to optimize the capture and charge-breeding efficiency of continuously injected singly charged ion beams. Following a brief overview of the reaccelerator system and the ReA EBIT, this paper presents the latest commissioning results, particularly, charge breeding and reacceleration of the highly charged rare isotopes, 76Ga24 +, 25 +.

  17. Commercial compact cyclotrons in the 90`s

    SciTech Connect

    Milton, B.F.

    1995-09-01

    Cyclotrons continue to be efficient accelerators for radio-isotope production. In recent years, developments in the accelerator technology have greatly increased the practical beam current in these machines while also improving the overall system reliability. These developments combined with the development of new isotopes for medicine and industry, and a retiring of older machines indicate a strong future for commercial cyclotrons. In this paper the authors will survey recent developments in the areas of cyclotron technology, as they relate to the new generation of commercial cyclotrons. Design criteria for the different types of commercial cyclotrons will be presented, with reference to those demands that differ from those in a research oriented cyclotron project. The authors also discuss the possibility of systems designed for higher energies and capable of extracted beam currents of up to 2.0 mA.

  18. Optimizing the emission, propagation, and focusing of an intense electron beam

    SciTech Connect

    Pepitone, K. Gardelle, J. Modin, P.

    2015-05-14

    Intense electron beams can be used to study the dynamical response of materials under shocks in order to adjust the models developed for hydrodynamics simulations. We present in this paper a characterization of beams produced in a field emission diode coupled to the generator RKA at CEA/CESTA. Cherenkov emission, produced by the beam interacting in a fused silica disk, was observed by fast optical cameras to estimate beam homogeneity. GEANT4 simulations were performed to estimate the transfer function of the silica target and to optimize the anode foil. First, we chose the best cathode material available among the most common materials used in field emission systems. In addition, we found that by optimization of the anode thickness, we could improve the spatial homogeneity of the beam which is of prime importance for computing the interaction of the beam with materials. Next, we changed the beam fluence by increasing the beam current and by reducing the beam radius. Finally, we studied the propagation and focusing of the electron beam in low pressure gases and observed that we could use self-magnetic field focusing in order to increase beam fluence at the target location. The experimental results are in good agreement with PIC simulations.

  19. Design of a compact Faraday cup for low energy, low intensity ion beams

    NASA Astrophysics Data System (ADS)

    Cantero, E. D.; Sosa, A.; Andreazza, W.; Bravin, E.; Lanaia, D.; Voulot, D.; Welsch, C. P.

    2016-01-01

    Beam intensity is one of the key parameters in particle accelerators, in particular during machine commissioning, but also during operation for experiments. At low beam energies and low intensities a number of challenges arise in its measurement as commonly used non-invasive devices are no longer sensitive enough. It then becomes necessary to stop the beam in order to measure its absolute intensity. A very compact Faraday cup for determining ion beam currents from a few nanoamperes down to picoamperes for the HIE-ISOLDE post-accelerator at CERN has been designed, built and tested with beam. It has a large aperture diameter of 30 mm and a total length of only 16 mm, making it one of the most compact designs ever used. In this paper we present the different steps that were involved in the design and optimization of this device, including beam tests with two early prototypes and the final monitor. We also present an analysis of the losses caused by secondary particle emission for different repelling electrode voltages and beam energies. Finally, we show that results obtained from an analytical model for electron loss probability combined with Monte Carlo simulations of particles trajectories provide a very good agreement with experimental data.

  20. Energy Loss of High Intensity Focused Proton Beams Penetrating Metal Foils

    NASA Astrophysics Data System (ADS)

    McGuffey, C.; Qiao, B.; Kim, J.; Beg, F. N.; Wei, M. S.; Evans, M.; Fitzsimmons, P.; Stephens, R. B.; Chen, S. N.; Fuchs, J.; Nilson, P. M.; Canning, D.; Mastrosimone, D.; Foord, M. E.

    2014-10-01

    Shortpulse-laser-driven intense ion beams are appealing for applications in probing and creating high energy density plasmas. Such a beam isochorically heats and rapidly ionizes any target it enters into warm dense matter with uncertain transport and stopping properties. Here we present experimental measurements taken with the 1.25 kJ, 10 ps OMEGA EP BL shortpulse laser of the proton and carbon spectra after passing through metal foils. The laser irradiated spherically curved C targets with intensity 4×1018 W/cm2, producing proton beams with 3 MeV slope temperature and a sharp low energy cutoff at 5 MeV which has not been observed on lower energy, shorter pulse intense lasers. The beam either diverged freely or was focused to estimated 1016 p +/cm2 ps by a surrounding structure before entering the metal foils (Al or Ag and a Cu tracer layer). The proton and ion spectra were altered by the foil depending on material and whether or not the beam was focused. Transverse proton radiography probed the target with ps temporal and 10 micron spatial resolution, indicating an electrostatic field on the foil may also have affected the beam. We present complementary particle-in-cell simulations of the beam generation and transport to the foils. This work was supported by the DOE/NNSA National Laser User Facility program, Contract DE-SC0001265.

  1. Extraction of intense beams from ECR ion sources and electrostatic acceleration

    NASA Astrophysics Data System (ADS)

    Cavenago, M.; Galata, A.

    2005-10-01

    High-space charge effects and problems related to beam transport are discussed in the context of an electron cyclotron-resonance ion sources extraction and pre-acceleration low emittance line (which works as the injector of a new superconducting Radio Frequency Quadruple (RFQ) under commissioning at Laboratori Nazionali di Legnaro (LNL)) at several values of the extracted beam current. In the extractor, both the cases of short-range magnetic fringe field (virtual source approximation) and large-range fringe field are simulated. Analytical expression of ion flow and plasma sheaths are easily incorporated in the charged fluid approach and in numerical modeling with three-dimensional simulation programs, which can treat several coupled field variables and lower space dimension (known as multiphysics codes). Advantages of flexibility and of representation of finer details are remarked. Effects of plasma potential and extraction hole thickness (0.5 mm) on the plasma meniscus can be resolved, even in the context of a simulation including 1 m long objects. An example of beam injection into an acceleration tube is also given, results are consistent with the tube-design goals and with the experimentally observed parameters.

  2. A high intensity H2 + multicusp ion source for the isotope decay-at-rest experiment, IsoDAR

    NASA Astrophysics Data System (ADS)

    Axani, S.; Winklehner, D.; Alonso, J.; Conrad, J. M.

    2016-02-01

    The Isotope Decay-At-Rest (IsoDAR) experimental program aims to decisively test the sterile neutrino hypothesis. In essence, it is a novel cyclotron based neutrino factory that will improve the frontiers in both high-intensity cyclotrons and electron flavor anti-neutrino sources. By using a source in which the usual H- ions are replaced with the more tightly bound H2 + ions, we can negate the effects of Lorentz stripping in a cyclotron, reduce the overall perveance due to the space-charge effect, and deliver twice the number of protons per nuclei on target. To produce the H2 + , we are currently developing a dedicated multicusp ion source, MIST-1 (generation-1 Multicusp Ion Source Technologies at MIT), and a low-energy beam transport system for the IsoDAR cyclotron. This will increase the overall H2 + current leading up to the cyclotron and improve the emittance of the beam injected into the cyclotron.

  3. Laser-driven beam lines for delivering intensity modulated radiation therapy with particle beams

    NASA Astrophysics Data System (ADS)

    Hofmann, K. M.; Schell, S.; Wilkens, J. J.

    2013-07-01

    Laser-accelerated particles can provide a promising opportunity for radiation therapy of cancer. Potential advantages arise from combining a compact, cost-efficient treatment unit with the physical advantages in dose delivery of charged particle beams. We consider different dose delivery schemes and the required devices to design a possible treatment unit. The secondary radiation produced in several beam line elements remains a challenge to be addressed.

  4. Laser-driven beam lines for delivering intensity modulated radiation therapy with particle beams

    SciTech Connect

    Hofmann, K. M.; Schell, S.; Wilkens, J. J.

    2013-07-26

    Laser-accelerated particles can provide a promising opportunity for radiation therapy of cancer. Potential advantages arise from combining a compact, cost-efficient treatment unit with the physical advantages in dose delivery of charged particle beams. We consider different dose delivery schemes and the required devices to design a possible treatment unit. The secondary radiation produced in several beam line elements remains a challenge to be addressed.

  5. The RHIC p-Carbon CNI Polarimeter Upgrade For The Beam Polarization And Intensity Measurements

    SciTech Connect

    Zelenski, A.; Bazilevski, A.; Bunce, G.; Gill, R.; Huang, H.; Mahler, G.; Makdisi, Y.; Morozov, B.; Nemesure, S.; Russo, T.; Steski, D.; Sivertz, M.

    2009-08-04

    Proton polarization measurements in the AGS and RHIC (Relativistic Heavy Ion Collider at the beam energies 24-250 GeV) are based on proton-carbon and proton-proton elastic scattering in the Coulomb Nuclear Interference (CNI) region. Polarimeter operation in the scanning mode also gives polarization profile and beam intensity profile (beam emittance) measurements. Bunch by bunch emittance measurement is a very powerful tool for machine setup. Presently, the polarization and beam intensity profile measurements (in both vertical and horizontal planes) are restricted by the long target switching time and possible target destruction during this complicated motion. The RHIC polarimeters were operated near the limit of the counting rate for present silicon strip detectors. The ongoing polarimeter upgrade for the 2009 run will address all these problems. The upgrade should allow significant reduction of the polarization measurement errors by making feasible the complete polarization measurements, which includes polarization profiles in both the horizontal and vertical planes.

  6. Resonant self-trapping of high intensity Bessel beams in underdense plasmas.

    PubMed

    Fan, J; Parra, E; Kim, K Y; Alexeev, I; Milchberg, H M; Cooley, J; Antonsen, T M

    2002-05-01

    We present a comprehensive report based on recent work [Phys. Rev. Lett. 84, 3085 (2000)] on resonant self-trapping and enhanced absorption of high power Bessel beams in underdense plasmas. The trapping resonance is strongly dependent on initial gas pressure, Bessel-beam geometry, and laser wavelength. Analytic estimates, and simulations using a one-dimensional Bessel-beam-plasma interaction code consistently explain the experimental observations. These results are for longer, moderate intensity pulses where the self-trapping channel is induced by laser-heated plasma thermal pressure. To explore the extension of this effect to ultrashort, intense pulsed Bessel beams, we perform propagation simulations using the code WAKE [Phys. Rev. E 53, R2068 (1996)]. We find that self-trapping can occur as a result of a plasma refractive index channel induced by the combined effects of relativistic motion of electrons and their ponderomotive expulsion. PMID:12059716

  7. Prospects and limitations of cyclotron resonance laser acceleration

    SciTech Connect

    Chen, C. )

    1992-07-01

    The cyclotron resonance laser (CRL) accelerator is a novel concept of accelerating continuous charged-particle beams to moderately or highly relativistic energies. This paper discusses prospects and limitations of this concept. In particular, a three-dimensional, self-consistent theory is used to analyze the nonlinear interaction of an electron beam with an intense traveling electromagnetic wave in such an accelerator. The parameter regimes of experimental interest are identified on the basis of scaling calculations. The results of simulation modeling of a multimegavolt electron CRL accelerator are presented. The possibility of building continuous-wave (cw) CRL accelerators is discussed.

  8. Ionization chamber response in intensity-modulated radiotherapy beams

    NASA Astrophysics Data System (ADS)

    Markovic, Alexander

    static beam penumbras but was not optimal when used with IMRT fields. Low numbers of monitor units delivered during each subfield of an IMRT treatment can force the linac control system to skip segments which introduces dosimetric error. For individual IMRT fields this effect accounted for an error of up to +/-4%. It was found that most of this error possesses a degree of randomness that is expected to cancel over the delivery of all fields in a clinical situation.

  9. The cyclotron development activities at CIAE

    NASA Astrophysics Data System (ADS)

    Zhang, Tianjue; Li, Zhenguo; An, Shizhong; Yin, Zhiguo; Yang, Jianjun; Yang, Fang

    2011-12-01

    The cyclotron has an obvious advantage in offering high average current and beam power. Cyclotron development for various applications, e.g. radioactive ion-beam (RIB) generation, clean nuclear energy systems, medical diagnostics and isotope production, were performed at China Institute of Atomic Energy (CIAE) for over 50 years. At the moment two cyclotrons are being built at CIAE, the 100 MeV, CYCIAE-100, and a 14 MeV, the CYCIAE-14. Meanwhile, we are designing and proposing to build a number of cyclotrons with different energies, among them are the CYCIAE-70, the CYCIAE-800, and the upgrading of CYCIAE-CRM, which is going to increase its beam current to mA level. The contribution will present an overall introduction to the cyclotron development activities conducted at CIAE, with different emphasis to each project in order to demonstrate the design and construction highlights.

  10. Nonlinear delta(f) Simulations of Collective Effects in Intense Charged Particle Beams

    SciTech Connect

    Hong Qin

    2003-01-21

    A nonlinear delta(f) particle simulation method based on the Vlasov-Maxwell equations has been recently developed to study collective processes in high-intensity beams, where space-charge and magnetic self-field effects play a critical role in determining the nonlinear beam dynamics. Implemented in the Beam Equilibrium, Stability and Transport (BEST) code [H. Qin, R.C. Davidson, and W.W. Lee, Physical Review -- Special Topics on Accelerator and Beams 3 (2000) 084401; 3 (2000) 109901.], the nonlinear delta(f) method provides a low-noise and self-consistent tool for simulating collective interactions and nonlinear dynamics of high-intensity beams in modern and next-generation accelerators and storage rings, such as the Spallation Neutron Source and heavy ion fusion drivers. A wide range of linear eigenmodes of high-intensity charged-particle beams can be systematically studied using the BEST code. Simulation results for the electron-proton two-stream instability in the Proton Storage Ring experiment [R. Macek, et al., in Proc. of the Particle Accelerator Conference, Chicago, 2001 (IEEE, Piscataway, NJ, 2001), Vol. 1, p. 688.] at the Los Alamos National Laboratory agree well with experimental observations. Large-scale parallel simulations have also been carried out for the ion-electron two-stream instability in the very-high-intensity heavy ion beams envisioned for heavy ion fusion applications. In both cases, the simulation results indicate that the dominant two-stream instability has a dipole-mode (hose-like) structure and can be stabilized by a modest axial momentum spread of the beam particles.

  11. 650 mm long liquid hydrogen target for use in a high intensity electron beam

    SciTech Connect

    Mark, J.W.

    1984-02-01

    This paper describes a 650 mm long liquid hydrogen targetr constructed for use in the high intensity electron beam at the Stanford Linear Accelerator Center (SLAC). The main design problem was to construct a target that would permit the heat deposited by the electron beam to be removed rapidly without boiling the hydrogen so as to maintain constant target density for optimum data taking. Design requirements, cosntruction details and operating experience are discussed.

  12. FEL on slow cyclotron wave

    SciTech Connect

    Silivra, A.

    1995-12-31

    A physical mechanism of interaction of fast electromagnetic wave with slow cyclotron wave of relativistic electron beam in a FEL with helical wiggler field is described. It is shown that: (1) interaction is possible for both group of steady state electron trajectories (2) positive gain is achieved within certain interval of guide field strength (3) operation wavelength for group 1 trajectories ({Omega}{sub 0}/{gamma} < k{omega}{upsilon}{parallel}) is shorter than for the conventional FEL synchronism. A nonlinear analysis shows that efficiency of slow cyclotron FEL is restricted mainly by a breakdown of a single electron synchronism due to dependence of (modified) electron cyclotron frequency on an energy of electron. Nevertheless, as numerical simulation shows, typical efficiency of 15 % order is achieved in millimeter wavelength band for the midrelativistic ({gamma}= 3 {divided_by} 4) slow cyclotron wave FEL. Tapering of magnetic field results in a substantial increase of efficiency.

  13. Probability density function of the intensity of a laser beam propagating in the maritime environment.

    PubMed

    Korotkova, Olga; Avramov-Zamurovic, Svetlana; Malek-Madani, Reza; Nelson, Charles

    2011-10-10

    A number of field experiments measuring the fluctuating intensity of a laser beam propagating along horizontal paths in the maritime environment is performed over sub-kilometer distances at the United States Naval Academy. Both above the ground and over the water links are explored. Two different detection schemes, one photographing the beam on a white board, and the other capturing the beam directly using a ccd sensor, gave consistent results. The probability density function (pdf) of the fluctuating intensity is reconstructed with the help of two theoretical models: the Gamma-Gamma and the Gamma-Laguerre, and compared with the intensity's histograms. It is found that the on-ground experimental results are in good agreement with theoretical predictions. The results obtained above the water paths lead to appreciable discrepancies, especially in the case of the Gamma-Gamma model. These discrepancies are attributed to the presence of the various scatterers along the path of the beam, such as water droplets, aerosols and other airborne particles. Our paper's main contribution is providing a methodology for computing the pdf function of the laser beam intensity in the maritime environment using field measurements. PMID:21997043

  14. Low-emittance monoenergetic electron and ion beams from ultra-intense laser-solid interactions

    SciTech Connect

    Cowan, T E; Roth, M; Allen, M M; Johnson, J; Hatchett, S P; Le Sage, G P; Wilks, S C

    2000-03-03

    Recent experiments at the LLNL Petawatt Laser have demonstrated the generation of intense, high energy beams of electrons and ions from the interaction of ultra-intense laser light with solid targets. Focused laser intensities as high as 6 x 10{sup 20} W/cm{sup 2} are achieved, at which point the quiver energies of the target electrons extend to {approx}10 MeV. In this new, fully relativistic regime of laser-plasma interactions, nuclear processes become important and nuclear techniques are required to diagnose the high-energy particle production. In recent experiments we have observed electrons accelerated to 100 MeV, up to 60 MeV brehmsstrahlung generation, photo-nuclear fission and positron-electron pair creation. We also have observed monoenergetic jets of electrons having sufficiently small emittance to be interesting as a laser-accelerated beam, if the production mechanism could be understood and controlled. The huge flux of multi-MeV ponderomotively accelerated electrons produced in the laser-solid interaction is also observed to accelerate contaminant ions from the rear surface of the solid target up to 50 MeV. We describe spectroscopic measurements which reveal intense monoenergetic beam features in the proton energy spectrum. The total spectrum contains >10{sup 13} protons, while the monoenergetic beam pulses contain {approx}1 nC of protons, and exhibits a longitudinal and transverse emittance smaller than conventional RF proton accelerator beams.

  15. Physics of Neutralization of Intense High-Energy Ion Beam Pulses by Electrons

    SciTech Connect

    Kaganovich, I. D.; Davidson, R. C.; Dorf, M. A.; Startsev, E. A.; Sefkow, A. B.; Lee, E. P.; Friedman, A.

    2010-04-28

    Neutralization and focusing of intense charged particle beam pulses by electrons forms the basis for a wide range of applications to high energy accelerators and colliders, heavy ion fusion, and astrophysics. For example, for ballistic propagation of intense ion beam pulses, background plasma can be used to effectively neutralize the beam charge and current, so that the self-electric and self- magnetic fields do not affect the ballistic propagation of the beam. From the practical perspective of designing advanced plasma sources for beam neutralization, a robust theory should be able to predict the self-electric and self-magnetic fields during beam propagation through the background plasma. The major scaling relations for the self-electric and self-magnetic fields of intense ion charge bunches propagating through background plasma have been determined taking into account the effects of transients during beam entry into the plasma, the excitation of collective plasma waves, the effects of gas ionization, finite electron temperature, and applied solenoidal and dipole magnetic fields. Accounting for plasma production by gas ionization yields a larger self-magnetic field of the ion beam compared to the case without ionization, and a wake of current density and self-magnetic field perturbations is generated behind the beam pulse. A solenoidal magnetic field can be applied for controlling the beam propagation. Making use of theoretical models and advanced numerical simulations, it is shown that even a small applied magnetic field of about 100G can strongly affect the beam neutralization. It has also been demonstrated that in the presence of an applied magnetic field the ion beam pulse can excite large-amplitude whistler waves, thereby producing a complex structure of self-electric and self-magnetic fields. The presence of an applied solenoidal magnetic field may also cause a strong enhancement of the radial self-electric field of the beam pulse propagating through the

  16. Physics of Neutralization of Intense Charged Particle Beam Pulses by a Background Plasma

    SciTech Connect

    Kaganovich, I.D.; Davidson, R.C.; Dorf, M.A.; Startsev, E.A.; Sefkow, A.B; Friedman, A.F.; Lee, E.P.

    2009-09-03

    Neutralization and focusing of intense charged particle beam pulses by a background plasma forms the basis for a wide range of applications to high energy accelerators and colliders, heavy ion fusion, and astrophysics. For example, for ballistic propagation of intense ion beam pulses, background plasma can be used to effectively neutralize the beam charge and current, so that the self-electric and self-magnetic fields do not affect the ballistic propagation of the beam. From the practical perspective of designing advanced plasma sources for beam neutralization, a robust theory should be able to predict the self-electric and self-magnetic fields during beam propagation through the background plasma. The major scaling relations for the self-electric and self-magnetic fields of intense ion charge bunches propagating through background plasma have been determined taking into account the effects of transients during beam entry into the plasma, the excitation of collective plasma waves, the effects of gas ionization, finite electron temperature, and applied solenoidal and dipole magnetic fields. Accounting for plasma production by gas ionization yields a larger self-magnetic field of the ion beam compared to the case without ionization, and a wake of current density and self-magnetic field perturbations is generated behind the beam pulse. A solenoidal magnetic field can be applied for controlling the beam propagation. Making use of theoretical models and advanced numerical simulations, it is shown that even a small applied magnetic field of about 100G can strongly affect the beam neutralization. It has also been demonstrated that in the presence of an applied magnetic field the ion beam pulse can excite large-amplitude whistler waves, thereby producing a complex structure of self-electric and self-magnetic fields. The presence of an applied solenoidal magnetic field may also cause a strong enhancement of the radial self-electric field of the beam pulse propagating

  17. Physics of neutralization of intense high-energy ion beam pulses by electrons

    SciTech Connect

    Kaganovich, I. D.; Davidson, R. C.; Dorf, M. A.; Startsev, E. A.; Sefkow, A. B.; Lee, E. P.; Friedman, A.

    2010-05-15

    Neutralization and focusing of intense charged particle beam pulses by electrons form the basis for a wide range of applications to high energy accelerators and colliders, heavy ion fusion, and astrophysics. For example, for ballistic propagation of intense ion beam pulses, background plasma can be used to effectively neutralize the beam charge and current, so that the self-electric and self-magnetic fields do not affect the ballistic propagation of the beam. From the practical perspective of designing advanced plasma sources for beam neutralization, a robust theory should be able to predict the self-electric and self-magnetic fields during beam propagation through the background plasma. The major scaling relations for the self-electric and self-magnetic fields of intense ion charge bunches propagating through background plasma have been determined taking into account the effects of transients during beam entry into the plasma, the excitation of collective plasma waves, the effects of gas ionization, finite electron temperature, and applied solenoidal and dipole magnetic fields. Accounting for plasma production by gas ionization yields a larger self-magnetic field of the ion beam compared to the case without ionization, and a wake of current density and self-magnetic field perturbations is generated behind the beam pulse. A solenoidal magnetic field can be applied for controlling the beam propagation. Making use of theoretical models and advanced numerical simulations, it is shown that even a small applied magnetic field of about 100 G can strongly affect the beam neutralization. It has also been demonstrated that in the presence of an applied magnetic field the ion beam pulse can excite large-amplitude whistler waves, thereby producing a complex structure of self-electric and self-magnetic fields. The presence of an applied solenoidal magnetic field may also cause a strong enhancement of the radial self-electric field of the beam pulse propagating through the

  18. Focusing of intense and divergent ion beams in a magnetic mass analyzer

    SciTech Connect

    Jianlin, Ke; Changgeng, Zhou; Rui, Qiu; Yonghong, Hu

    2014-07-15

    A magnetic mass analyzer is used to determine the beam composition of a vacuum arc ion source. In the analyzer, we used the concentric multi-ring electrodes to focus the intense and divergent ion beams. We describe the principle, design, and the test results of the focusing device. The diameter of the beam profile is less than 20 mm when the accelerating voltage is 30 kV and the focusing voltage is about 2.0 kV. The focusing device has been successfully used in the magnetic mass analyzer to separate Ti{sup +}, Ti{sup 2+}, and Ti{sup 3+}.

  19. Development of a silicon micro-strip detector for tracking high intensity secondary beams

    NASA Astrophysics Data System (ADS)

    Kiuchi, R.; Asano, H.; Hasegawa, S.; Honda, R.; Ichikawa, Y.; Imai, K.; Joo, C. W.; Nakazawa, K.; Sako, H.; Sato, S.; Shirotori, K.; Sugimura, H.; Tanida, K.; Watabe, T.

    2014-11-01

    A single-sided silicon micro-strip detector (SSD) has been developed as a tracking detector for hadron experiments at J-PARC where secondary meson beams with intensities of up to 108 Hz are available. The performance of the detector has been investigated and verified in a series of test beam experiments in the years 2009-2011. The hole mobility was deduced from the analysis of cluster events. The beam rate dependence was measured in terms of timing resolution, signal-to-noise ratio, and hit efficiency. This paper describes the detector with its read-out system, details of the test experiments, and discusses the performance achieved.

  20. Hose instability and wake generation by an intense electron beam in a self-ionized gas.

    PubMed

    Deng, S; Barnes, C D; Clayton, C E; O'Connell, C; Decker, F J; Fonseca, R A; Huang, C; Hogan, M J; Iverson, R; Johnson, D K; Joshi, C; Katsouleas, T; Krejcik, P; Lu, W; Mori, W B; Muggli, P; Oz, E; Tsung, F; Walz, D; Zhou, M

    2006-02-01

    The propagation of an intense relativistic electron beam through a gas that is self-ionized by the beam's space charge and wakefields is examined analytically and with 3D particle-in-cell simulations. Instability arises from the coupling between a beam and the offset plasma channel it creates when it is perturbed. The traditional electron hose instability in a preformed plasma is replaced with this slower growth instability depending on the radius of the ionization channel compared to the electron blowout radius. A new regime for hose stable plasma wakefield acceleration is suggested. PMID:16486834

  1. Stationary self-focusing of intense laser beam in cold quantum plasma using ramp density profile

    SciTech Connect

    Habibi, M.; Ghamari, F.

    2012-10-15

    By using a transient density profile, we have demonstrated stationary self-focusing of an electromagnetic Gaussian beam in cold quantum plasma. The paper is devoted to the prospects of using upward increasing ramp density profile of an inhomogeneous nonlinear medium with quantum effects in self-focusing mechanism of high intense laser beam. We have found that the upward ramp density profile in addition to quantum effects causes much higher oscillation and better focusing of laser beam in cold quantum plasma in comparison to that in the classical relativistic case. Our computational results reveal the importance and influence of formation of electron density profiles in enhancing laser self-focusing.

  2. Hose Instability and Wake Generation By An Intense Electron Beam in a Self-Ionized Gas

    SciTech Connect

    Deng, S.; Barnes, C.D.; Clayton, C.E.; O'Connell, C.; Decker, F.J.; Fonseca, R.A.; Huang, C.; Hogan, M.J.; Iverson, R.; Johnson, D.K.; Joshi, C.; Katsouleas, T.; Krejcik, P.; Lu, W.; Mori, W.B.; Muggli, P.; Oz, E.; Tsung, F.; Walz, D.; Zhou, M.; /Southern California U. /UCLA /SLAC

    2006-04-12

    The propagation of an intense relativistic electron beam through a gas that is self-ionized by the beam's space charge and wakefields is examined analytically and with 3D particle-in-cell simulations. Instability arises from the coupling between a beam and the offset plasma channel it creates when it is perturbed. The traditional electron hose instability in a preformed plasma is replaced with this slower growth instability depending on the radius of the ionization channel compared to the electron blowout radius. A new regime for hose stable plasma wakefield acceleration is suggested.

  3. Generation of equal-intensity coherent optical beams by binary geometrical phase on metasurface

    NASA Astrophysics Data System (ADS)

    Wang, Zheng-Han; Jiang, Shang-Chi; Xiong, Xiang; Peng, Ru-Wen; Wang, Mu

    2016-06-01

    We report here the design and realization of a broadband, equal-intensity optical beam splitter with a dispersion-free binary geometric phase on a metasurface with unit cell consisting of two mirror-symmetric elements. We demonstrate experimentally that two identical beams can be efficiently generated with incidence of any polarization. The efficiency of the device reaches 80% at 1120 nm and keeps larger than 70% in the range of 1000-1400 nm. We suggest that this approach for generating identical, coherent beams have wide applications in diffraction optics and in entangled photon light source for quantum communication.

  4. Observations of the filamentation of high-intensity laser-produced electron beams

    SciTech Connect

    Wei, M.S.; Beg, F.N.; Dangor, A.E.; Gopal, A.; Tatarakis, M.; Krushelnick, K.; Clark, E.L.; Evans, R.G.; Ledingham, K.W.D.; McKenna, P.; Norreys, P.A.; Zepf, M.

    2004-11-01

    Filamented electron beams have been observed to be emitted from the rear of thin solid targets irradiated by a high-intensity short-pulse laser when there is low-density plasma present at the back of the target. These observations are consistent with a laser-generated beam of relativistic electrons propagating through the target, which is subsequently fragmented by a Weibel-like instability in the low-density plasma at the rear. These measurements are in agreement with particle-in-cell simulations and theory, since the filamentation instability is predicted to be dramatically enhanced when the electron beam density approaches that of the background plasma.

  5. Propagation of an intense laser beam in a tapered plasma channel

    SciTech Connect

    Jha, Pallavi; Singh, Ram Gopal; Upadhyaya, Ajay K.; Mishra, Rohit K.

    2008-03-15

    Propagation characteristics and modulation instability of an intense laser beam propagating in an axially tapered plasma channel, having a parabolic radial density profile, are studied. Using the source-dependent expansion technique, the evolution equation for the laser spot is set up and conditions for propagation of the laser beam with a constant spot size (matched beam) are obtained. Further, the dispersion relation and growth rate of modulation instability of the laser pulse as it propagates through linearly and quadratically tapered plasma channels, have been obtained.

  6. Long path-length experimental studies of longitudinal phenomena in intense beams

    NASA Astrophysics Data System (ADS)

    Beaudoin, B. L.; Haber, I.; Kishek, R. A.; Bernal, S.; Koeth, T. W.

    2016-05-01

    Intense charged particle beams are nonneutral plasmas as they can support a host of plasma waves and instabilities. The longitudinal physics, for a long beam, can often be reasonably described by a 1-D cold-fluid model with a geometry factor to account for the transverse effects. The plasma physics of such beams has been extensively studied theoretically and computationally for decades, but until recently, the only experimental measurements were carried out on relatively short linacs. This work reviews experimental studies over the past five years on the University of Maryland Electron Ring, investigating longitudinal phenomena over time scales of thousands of plasma periods, illustrating good agreement with simulations.

  7. Self-consistent simulation studies of periodically focused intense charged-particle beams

    NASA Astrophysics Data System (ADS)

    Chen, C.; Jameson, R. A.

    1995-09-01

    A self-consistent two-dimensional model is used to investigate intense charged-particle beam propagation through a periodic solenoidal focusing channel, particularly in the regime in which there is a mismatch between the beam and the focusing channel. The present self-consistent studies confirm that mismatched beams exhibit nonlinear resonances and chaotic behavior in the envelope evolution, as predicted by an earlier envelope analysis [C. Chen and R. C. Davidson, Phys. Rev. Lett. 72, 2195 (1994)]. Transient effects due to emittance growth are studied, and halo formation is investigated. The halo size is estimated. The halo characteristics for a periodic focusing channel are found to be qualitatively the same as those for a uniform focusing channel. A threshold condition is obtained numerically for halo formation in mismatched beams in a uniform focusing channel, which indicates that relative envelope mismatch must be kept well below 20% to prevent space-charge-dominated beams from developing halos.

  8. Focusing of short-pulse high-intensity laser-accelerated proton beams

    NASA Astrophysics Data System (ADS)

    Bartal, Teresa; Foord, Mark E.; Bellei, Claudio; Key, Michael H.; Flippo, Kirk A.; Gaillard, Sandrine A.; Offermann, Dustin T.; Patel, Pravesh K.; Jarrott, Leonard C.; Higginson, Drew P.; Roth, Markus; Otten, Anke; Kraus, Dominik; Stephens, Richard B.; McLean, Harry S.; Giraldez, Emilio M.; Wei, Mingsheng S.; Gautier, Donald C.; Beg, Farhat N.

    2012-02-01

    Recent progress in generating high-energy (>50MeV) protons from intense laser-matter interactions (1018-1021Wcm-2 refs , , , , , , ) has opened up new areas of research, with applications in radiography, oncology, astrophysics, medical imaging, high-energy-density physics, and ion-proton beam fast ignition. With the discovery of proton focusing with curved surfaces, rapid advances in these areas will be driven by improved focusing technologies. Here we report on the first investigation of the generation and focusing of a proton beam using a cone-shaped target. We clearly show that the focusing is strongly affected by the electric fields in the beam in both open and enclosed (cone) geometries, bending the trajectories near the axis. Also in the cone geometry, a sheath electric field effectively `channels' the proton beam through the cone tip, substantially improving the beam focusing properties. These results agree well with particle simulations and provide the physics basis for many future applications.

  9. Rapid Cycling Synchrotrons and Accumulator Rings for High-Intensity Hadron Beams

    NASA Astrophysics Data System (ADS)

    Tang, Jingyu

    2014-02-01

    Boosted by the needs in high-energy physics and nuclear physics and also multidisciplinary applications, high-intensity proton synchrotrons and accumulator rings have been developed quickly around the world over the last 30 years. New projects and plans are proposed with even higher beam power. The proton beam power has increased from less than 10 kW in the 1970s to about 1 MW level today, and the required beam power in the coming decade is a few MW. This article reviews the achievements in designing and constructing rapid cycling synchrotrons (RCSs) and accumulator rings (ARs) and the future development trends, principally on proton beams but also including heavy ion beams. It presents the evolution of RCS and AR machines, today's design philosophy, relevant accelerator physics, and also state-of-the-art accelerator technology.

  10. A mask for high-intensity heavy-ion beams in the MAYA active target

    NASA Astrophysics Data System (ADS)

    Rodríguez-Tajes, C.; Pancin, J.; Damoy, S.; Roger, T.; Babo, M.; Caamaño, M.; Farget, F.; Grinyer, G. F.; Jacquot, B.; Pérez-Loureiro, D.; Ramos, D.; Suzuki, D.

    2014-12-01

    The use of high-intensity and/or heavy-ion beams in active targets and time-projection chambers is often limited by the strong ionization produced by the beam. Besides the difficulties associated with the saturation of the detector and electronics, beam-related signals may hide the physical events of interest or reduce the detector performance. In addition, space-charge effects may deteriorate the homogeneity of the electric drift field and distort the subsequent reconstruction of particle trajectories. In anticipation of future projects involving such conditions, a dedicated beam mask has been developed and tested in the MAYA active target. Experimental results with a 136Xe beam are presented.

  11. Nonlinear interaction of intense hypergeometric Gaussian subfamily laser beams in plasma

    NASA Astrophysics Data System (ADS)

    Sobhani, H.; Vaziri (Khamedi), M.; Rooholamininejad, H.; Bahrampour, A. R.

    2016-07-01

    Propagation of Hypergeometric-Gaussian laser beam in a nonlinear plasma medium is investigated by considering the Source Dependent Expansion method. A subfamily of Hypergeometric-Gaussian beams with a non-negative, even and integer radial index, can be expressed as the linear superposition of finite number of Laguerre-Gaussian functions. Propagation of Hypergeometric-Gaussian beams in a nonlinear plasma medium depends on the value of radial index. The bright rings' number of these beams is changed during the propagation in plasma medium. The effect of beam vortex charge number l and initial (input) beam intensity on the self-focusing of Hypergeometric-Gaussian beams is explored. Also, by choosing the suitable initial conditions, Hypergeometric-Gaussian subfamily beams can be converted to one or more mode components that a typical of mode conversion may be occurred. The self-focusing of these winding beams can be used to control the focusing force and improve the electron bunch quality in laser plasma accelerators.

  12. Intial characterization fo a commerical electron gun for profiling high intensity proton beams in Project X

    SciTech Connect

    Thurman-Keup, R.; Johnson, A.S.; Lumpkin, A.H.; Thangaraj, J.C.T.; Zhang, D.; Blokland, W.; /Oak Ridge

    2011-03-01

    Measuring the profile of a high-intensity proton beam is problematic in that traditional invasive techniques such as flying wires don't survive the encounter with the beam. One alternative is the use of an electron beam as a probe of the charge distribution in the proton beam as was done at the Spallation Neutron Source at ORNL. Here we present an initial characterization of the beam from a commercial electron gun from Kimball Physics, intended for use in the Fermilab Main Injector for Project X. Despite the fact that the horizontal spot size is abnormally large in the high current measurement, the spot size at the downstream cross X2 is reasonable in the context of measuring the deflection. A thin foil OTR would help with the beam heating and should be tried. The next phase of this experiment is to simulate the proton beam with a pair of current carrying wires and to design and construct a fast deflector. Some of the remaining issues to be considered include determining the minimum beam current needed to observe the deflected beam for a given sweep time and the impact of longitudinal variations in the charge density of the bunch.

  13. A high-current electron gun for the electron beam ion trap at the National Superconducting Cyclotron Laboratory

    SciTech Connect

    Schwarz, S. Baumann, T. M.; Kittimanapun, K.; Lapierre, A.; Snyder, A.

    2014-02-15

    The Electron Beam Ion Trap (EBIT) in NSCL’s reaccelerator ReA uses continuous ion injection and accumulation. In order to maximize capture efficiency and minimize breeding time into high charge states, the EBIT requires a high-current/high current-density electron beam. A new electron gun insert based on a concave Ba-dispenser cathode has been designed and built to increase the current transmitted through the EBIT’s superconducting magnet. With the new insert, stable EBIT operating conditions with 0.8 A of electron beam have been established. The design of the electron gun is presented together with calculated and measured perveance data. In order to assess the experimental compression of the electron beam, a pinhole CCD camera has been set up to measure the electron beam radius. The camera observes X-rays emitted from highly charged ions, excited by the electron beam. Initial tests with this camera setup will be presented. They indicate that a current density of 640 A/cm{sup 2} has been reached when the EBIT magnet was operated at 4 T.

  14. A high-current electron gun for the electron beam ion trap at the National Superconducting Cyclotron Laboratory.

    PubMed

    Schwarz, S; Baumann, T M; Kittimanapun, K; Lapierre, A; Snyder, A

    2014-02-01

    The Electron Beam Ion Trap (EBIT) in NSCL's reaccelerator ReA uses continuous ion injection and accumulation. In order to maximize capture efficiency and minimize breeding time into high charge states, the EBIT requires a high-current/high current-density electron beam. A new electron gun insert based on a concave Ba-dispenser cathode has been designed and built to increase the current transmitted through the EBIT's superconducting magnet. With the new insert, stable EBIT operating conditions with 0.8 A of electron beam have been established. The design of the electron gun is presented together with calculated and measured perveance data. In order to assess the experimental compression of the electron beam, a pinhole CCD camera has been set up to measure the electron beam radius. The camera observes X-rays emitted from highly charged ions, excited by the electron beam. Initial tests with this camera setup will be presented. They indicate that a current density of 640 A/cm(2) has been reached when the EBIT magnet was operated at 4 T. PMID:24593604

  15. A high-current electron gun for the electron beam ion trap at the National Superconducting Cyclotron Laboratory

    NASA Astrophysics Data System (ADS)

    Schwarz, S.; Baumann, T. M.; Kittimanapun, K.; Lapierre, A.; Snyder, A.

    2014-02-01

    The Electron Beam Ion Trap (EBIT) in NSCL's reaccelerator ReA uses continuous ion injection and accumulation. In order to maximize capture efficiency and minimize breeding time into high charge states, the EBIT requires a high-current/high current-density electron beam. A new electron gun insert based on a concave Ba-dispenser cathode has been designed and built to increase the current transmitted through the EBIT's superconducting magnet. With the new insert, stable EBIT operating conditions with 0.8 A of electron beam have been established. The design of the electron gun is presented together with calculated and measured perveance data. In order to assess the experimental compression of the electron beam, a pinhole CCD camera has been set up to measure the electron beam radius. The camera observes X-rays emitted from highly charged ions, excited by the electron beam. Initial tests with this camera setup will be presented. They indicate that a current density of 640 A/cm2 has been reached when the EBIT magnet was operated at 4 T.

  16. The University of Maryland Electron Ring: A Model Recirculator for Intense Beam Physics Research

    SciTech Connect

    Bernal, S.; Li, H.; Cui, Y.; Feldman, D.; Godlove, T.; Haber, I.; Huo, Y.; Harris, J.; Kishek, R.A.; Quinn, B.; Reiser, M.; Walter, M.; Wilson, M.; Zou, Y.; O'Shea, P.G.

    2004-12-07

    The University of Maryland Electron Ring (UMER), designed for transport studies of space-charge dominated beams in a strong focusing lattice, is nearing completion. Low energy, high intensity electron beams provide an excellent model system for experimental studies with relevance to all areas that require high quality, intense charged-particle beams. In addition, UMER constitutes an important tool for benchmarking of computer codes. When completed, the UMER lattice will consist of 36 alternating-focusing (FODO) periods over an 11.5-m circumference. Current studies in UMER over about 2/3 of the ring include beam-envelope matching, halo formation, asymmetrical focusing, and longitudinal dynamics (beam bunch erosion and wave propagation.) Near future, multi-turn operation of the ring will allow us to address important additional issues such as resonance-traversal, energy spread and others. The main diagnostics are phosphor screens and capacitive beam position monitors placed at the center of each 200 bending section. In addition, pepper-pot and slit-wire emittance meters are in operation. The range of beam currents used corresponds to space charge tune depressions from 0.2 to 0.8, which is unprecedented for a circular machine.

  17. High-intensity, high-brightness polarized and unpolarized beam production in charge-exchange collisions

    SciTech Connect

    Zelenski, A.; Ritter, J.; Zubets, V.; Steski, D.; Atoian, G.; Davydenko, V.; Ivanov, A.; Kolmogorov, A.

    2011-03-28

    Basic limitations on the high-intensity H{sup -} ion beam production were experimentally studied in charge-exchange collisions of the neutral atomic hydrogen beam in the Na-vapour jet ionizer cell. These studies are the part of the polarized source upgrade (to 10 mA peak current and 85% polarization) project for RHIC. In the source the atomic hydrogen beam of a 5-10 keV energy and total (equivalent) current up to 5 A is produced by neutralization of proton beam in pulsed hydrogen gas target. Formation of the proton beam (from the surface of the plasma emitter with a low transverse ion temperature {approx}0.2 eV) is produced by four-electrode spherical multi-aperture ion-optical system with geometrical focusing. The hydrogen atomic beam intensity up to 1.0 A/cm{sup 2} (equivalent) was obtained in the Na-jet ionizer aperture of a 2.0 cm diameter. At the first stage of the experiment H-beam with 36 mA current, 5 keV energy and {approx}1.0 cm {center_dot} mrad normalized emittance was obtained using the flat grids and magnetic focusing.

  18. Evaluation of intensity based beam-shaping method with Rib-phantom HIFU sonications

    NASA Astrophysics Data System (ADS)

    Tillander, Matti; Köhler, Max; Koskela, Julius; Ylihautala, Mika

    2012-11-01

    The relation between rib bone heating during HIFU therapy and incident intensity on the bone surface was examined using an experimental setup and simulations with ray-tracer. The relation was found to be linear yet the data had large variance. The result was successfully applied to an intensity-based beam-shaping algorithm, which was fast enough for online therapy planning, and used to protect the ribs from overheating during intercostal sonications to a HIFU phantom containing two porcine rib bones.

  19. Spatial shaping of intense femtosecond beams for the generation of high-energy attosecond pulses

    NASA Astrophysics Data System (ADS)

    Constant, E.; Dubrouil, A.; Hort, O.; Petit, S.; Descamps, D.; Mével, E.

    2012-04-01

    We generate high-order harmonics with a spatially shaped TW laser beam. We present and analyse in detail a new approach for shaping an intense laser field to a flat-top intensity profile near focus. We show that this approach is well adapted for high harmonic generation with high-energy fundamental pulses and highlight the possibilities for generating high-energy attosecond pulses.

  20. Computer-assisted selection of coplanar beam orientations in intensity-modulated radiation therapy*

    NASA Astrophysics Data System (ADS)

    Pugachev, A.; Xing, L.

    2001-09-01

    In intensity-modulated radiation therapy (IMRT), the incident beam orientations are often determined by a trial and error search. The conventional beam's-eye view (BEV) tool becomes less helpful in IMRT because it is frequently required that beams go through organs at risk (OARs) in order to achieve a compromise between the dosimetric objectives of the planning target volume (PTV) and the OARs. In this paper, we report a beam's-eye view dosimetrics (BEVD) technique to assist in the selection of beam orientations in IMRT. In our method, each beam portal is divided into a grid of beamlets. A score function is introduced to measure the `goodness' of each beamlet at a given gantry angle. The score is determined by the maximum PTV dose deliverable by the beamlet without exceeding the tolerance doses of the OARs and normal tissue located in the path of the beamlet. The overall score of the gantry angle is given by a sum of the scores of all beamlets. For a given patient, the score function is evaluated for each possible beam orientation. The directions with the highest scores are then selected as the candidates for beam placement. This procedure is similar to the BEV approach used in conventional radiation therapy, except that the evaluation by a human is replaced by a score function to take into account the intensity modulation. This technique allows one to select beam orientations without the excessive computing overhead of computer optimization of beam orientation. It also provides useful insight into the problem of selection of beam orientation and is especially valuable for complicated cases where the PTV is surrounded by several sensitive structures and where it is difficult to select a set of `good' beam orientations. Several two-dimensional (2D) model cases were used to test the proposed technique. The plans obtained using the BEVD-selected beam orientations were compared with the plans obtained using equiangular spaced beams. For all the model cases investigated

  1. System for obtaining smooth laser beams where intensity variations are reduced by spectral dispersion of the laser light (SSD)

    DOEpatents

    Skupsky, Stanley; Kessler, Terrance J.; Short, Robert W.; Craxton, Stephen; Letzring, Samuel A.; Soures, John

    1991-01-01

    In an SSD (smoothing by spectral dispersion) system which reduces the time-averaged spatial variations in intensity of the laser light to provide uniform illumination of a laser fusion target, an electro-optic phase modulator through which a laser beam passes produces a broadband output beam by imposing a frequency modulated bandwidth on the laser beam. A grating provides spatial and angular spectral dispersion of the beam. Due to the phase modulation, the frequencies ("colors") cycle across the beam. The dispersed beam may be amplified and frequency converted (e.g., tripled) in a plurality of beam lines. A distributed phase plate (DPP) in each line is irradiated by the spectrally dispersed beam and the beam is focused on the target where a smooth (uniform intensity) pattern is produced. The color cycling enhances smoothing and the use of a frequency modulated laser pulse prevents the formation of high intensity spikes which could damage the laser medium in the power amplifiers.

  2. Investigation of Generation, Acceleration, Transport and Final Focusing of High-Intensity Heavy Ion Beams from Sources to Targets

    SciTech Connect

    Chiping Chen

    2006-10-26

    Under the auspices of the research grant, the Intense Beam Theoretical Research Goup at Massachusetts Institute of Technology's Plasma Science and Fusion Center made significant contributions in a number of important areas in the HIF and HEDP research, including: (a) Derivation of rms envelope equations and study of rms envelope dynamics for high-intensity heavy ion beams in a small-aperture AG focusing transport systems; (b) Identification of a new mechanism for chaotic particle motion, halo formation, and beam loss in high-intensity heavy ion beams in a small-aperture AG focusing systems; Development of elliptic beam theory; (d) Study of Physics Issues in the Neutralization Transport Experiment (NTX).

  3. Excitation of broadband electrostatic noise and of hydrogen cyclotron waves by a perpendicular ion beam in multi-ion plasma

    NASA Astrophysics Data System (ADS)

    Malingre, M.; Pottelette, R.

    1985-05-01

    Results from the PORCUPINE experiment show that a perpendicular heavy ion beams, injected into an O(+) dominated plasma which contains a small concentration of H(+), induces a broadband electrostatic noise near the lower hybrid frequency and also discrete elecrostatic emissions at frequencies close to multiples of the hydrogen gyrofrequency. The dependence of these instabilities on the parameters characteristics of the beam-background plasma system is studied. It is shown that, provided the beam is of sufficiently high density and low temperature, the frequency range of the broadband noise extends continuously from zero frequency up to the lower hybrid frequency. In this case the harmonics of the hydrogen gyrofrequency are also excited but their growth rates are much lower than that of the broadband emission, up to two of three orders of magnitude for the first harmonics.

  4. Nonlinear Delta-f Particle Simulations of Collective Effects in High Intensity Charged Particle Beams

    NASA Astrophysics Data System (ADS)

    Qin, Hong; Davidson, Ronald C.; Startsev, Edward A.

    2004-11-01

    A wide range of collective effects in high intensity charged particle beams have been numerically studied using the nonlinear delta-f particle simulation method implemented in the Beam Equilibrium Stability and Transport (BEST) code. For the electron-ion two-stream instability in high intensity accelerators and storage rings, the secondary electron yield effects are self-consistently studied by coupling the secondary electron yield library CMEE with the instability simulations. Progress has also been made in applying the delta-f particle simulation method to bunched beams, and a three-dimensional equilibrium solver has been implemented. With the help of recently developed parallel diagnostic techniques, we are able to characterize the chaotic particle dynamics under the influences of collective instabilities as well as three-dimensional equilibrium fields. To further extend the application areas of the delta-f particle simulation method, 2D domain decomposition is being developed using the Message Passing Interface, and three-dimensional equilibria with anisotropic temperature in the transverse and longitudinal directions are being investigated. References: [1] R. C. Davidson and H. Qin, An Introduction to the Physics of Intense Charged Particle Beams in High Energy Accelerators, World Scientific (2001). [2] H. Qin, Physics of Plasmas 10, 2078 (2003). [3] H. Qin, E. A. Startsev, and R. C. Davidson, Physical Review Special Topics on Accelerators and Beams 6, 014401 (2003).

  5. Weibel and Two-Stream Instabilities for Intense Charged Particle Beam Propagation through Neutralizing Background Plasma

    SciTech Connect

    Ronald C. Davidson; Igor Kaganovich; Edward A. Startsev

    2004-04-09

    Properties of the multi-species electromagnetic Weibel and electrostatic two-stream instabilities are investigated for an intense ion beam propagating through background plasma. Assuming that the background plasma electrons provide complete charge and current neutralization, detailed linear stability properties are calculated within the framework of a macroscopic cold-fluid model for a wide range of system parameters.

  6. Assessment of beam intensity profiles in an iodine laser using optical fibers

    NASA Astrophysics Data System (ADS)

    Raffo, C. A.; Rebollo, M. A.; Doti, R.

    1985-05-01

    A method has been developed for measuring the spatial profile of the output beam of an iodine laser at 1.315 μm, which requires only using two optical fibers, one for collecting a reference signal and the other for detecting the laser intensity at a given point of the wavefront. The precision is sufficient for laser engineering purposes.

  7. Michigan state upgrade to produce intense radioactive ion beams by fragmentation technique

    SciTech Connect

    Lubkin, G.B.

    1997-05-01

    This article describes the planned upgrading of accelerator facilities to produce intense radioactive ion beams, by a fragmentation technique, for experimental simulation of nucleosynthesis in novas and supernovas. (AIP) {ital 1997 American Institute of Physics.} {copyright} {ital 1997} {ital American Institute of Physics}

  8. Macroscopic Description of Pressure-anisotropy-driven Collective Instability in Intense Charged Particle Beams

    SciTech Connect

    Sean Strasburg; Ronald C. Davidson

    2000-05-30

    The macroscopic warm-fluid model developed by Lund and Davidson [Phys.Plasmas 5, 3028 (1998)] is used in the smooth-focusing approximation to investigate detailed stability properties of an intense charged particle beam with pressure anisotropy, assuming small-amplitude electrostatic pertubations about a waterbag equilibrium.

  9. Commissioning the new high power rf system for the AGS with high intensity beam

    SciTech Connect

    Brennan, J.M.; Ciardullo, D.J.; Deng, D.P; Hayes, T.; Onillon, E.; Otis, A.; Sanders, R.T.; Zaltsman, A.

    1994-08-01

    A new high power rf system has been installed in the AGS in order to raise the beam loading limit to beyond 6 {times} 10{sup 13} protons per pulse. The old system was limited to 2.2 {times} 10{sup l3} ppp by: available real power, multi-loop instability, and transient beam loading during batch filling from the Booster. The key components of the new system are: new power amplifiers in the tunnel using the Thomson-CSF TH573 300kW tetrode, rf feedback around the power stage, and reduction of the 10 cavities` R/Q by 1.8 by additional gap capacitors. Commissioning of the new rf system with high intensity beam is described. The intensity goal for the 1994 running period is 4 {times} 10{sup 13} ppp. To date, 3.7 {times} 10{sup 13} ppp has been achieved.

  10. Thermomagnetic recording and magneto-optic playback system having constant intensity laser beam control

    NASA Technical Reports Server (NTRS)

    Lewicki, G. W.; Guisinger, J. E. (Inventor)

    1973-01-01

    A system is developed for maintaining the intensity of a laser beam at a constant level in a thermomagnetic recording and magneto-optic playback system in which an isotropic film is heated along a continuous path by the laser beam for recording. As each successive area of the path is heated locally to the vicinity of its Curie point in the presence of a controlled magnetic field, a magneto-optic density is produced proportional to the amplitude of the controlled magnetic field. To play back the recorded signal, the intensity of the laser beam is reduced and a Faraday or Kerr effect analyzer is used, with a photodetector, as a transducer for producing an output signal.

  11. Ion Beams in Short-Pulse, High Intensity Laser Matter Interactions.

    NASA Astrophysics Data System (ADS)

    Lasinski, B. F.; Langdon, A. B.; Still, C. H.; Tabak, M.; Town, R. P. J.; Kruer, W. L.; Wilks, S. C.; Welch, D. R.

    2002-11-01

    Experiments on the interaction of short pulse high intensity lasers with thin foils have produced intense ion beams with surprisingly good emittance. We report on explicit PIC and hybrid particle-fluid simulations motivated by these experiments. In addition, we study the focusing of these beams and their possible collective effects. The LSP code footnote D. R. Welch, et al, Nucl. Inst. Meth. Phys. Res. A 242, 134 (2001). uses a direct implicit particle-in-cell algorithm in 2 or 3 dimensions to solve for the beam particles and the background particles are treated as a fluid. Implications for the fast ignitor concept footnote M. Tabak, et al, Phys. Plasmas 1, 1626 (1994). in which energetic fast particles transport energy to the high-density compressed fuel will be discussed.

  12. Calculation of synchrotron radiation from high intensity electron beam at eRHIC

    SciTech Connect

    Jing Y.; Chubar, O.; Litvinenko, V.

    2012-05-20

    The Electron-Relativistic Heavy Ion Collider (eRHIC) at Brookhaven National Lab is an upgrade project for the existing RHIC. A 30 GeV energy recovery linac (ERL) will provide a high charge and high quality electron beam to collide with proton and ion beams. This will improve the luminosity by at least 2 orders of magnitude. The synchrotron radiation (SR) from the bending magnets and strong quadrupoles for such an intense beam could be penetrating the vacuum chamber and producing hazards to electronic devices and undesired background for detectors. In this paper, we calculate the SR spectral intensity, power density distributions and heat load on the chamber wall. We suggest the wall thickness required to stop the SR and estimate spectral characteristics of the residual and scattered background radiation outside the chamber.

  13. Scintillating screens sensitivity and resolution studies for low energy, low intensity beam diagnostics.

    PubMed

    Harasimowicz, Janusz; Cosentino, Luigi; Finocchiaro, Paolo; Pappalardo, Alfio; Welsch, Carsten P

    2010-10-01

    In order to investigate the limits of scintillating screens for beam profile monitoring in the ultra-low energy, ultra-low intensity regime, CsI:Tl, YAG:Ce, and a Tb glass-based scintillating fiber optic plate (SFOP) were tested. The screens response to 200 and 50 keV proton beams with intensities ranging from a few picoampere down to the subfemtoampere region was examined. In the following paper, the sensitivity and resolution studies are presented in detail for CsI:Tl and the SFOP, the two most sensitive screens. In addition, a possible use of scintillators for ultra-low energy antiproton beam monitoring is discussed. PMID:21034082

  14. Paul Trap Simulator Experiment to Model Intense Beam Propagation in Alternating-gradient Transport Systems

    SciTech Connect

    Erik P. Gilson; Ronald C. Davidson; Philip C. Efthimion; Richard Majeski

    2004-01-29

    The results presented here demonstrate that the Paul Trap Simulator Experiment (PTSX) simulates the propagation of intense charged particle beams over distances of many kilometers through magnetic alternating-gradient (AG) transport systems by making use of the similarity between the transverse dynamics of particles in the two systems. Plasmas have been trapped that correspond to normalized intensity parameters s = wp2 (0)/2wq2 * 0.8, where wp(r) is the plasmas frequency and wq is the average transverse focusing frequency in the smooth-focusing approximation. The measured root-mean-squared (RMS) radius of the beam is consistent with a model, equally applicable to both PTSX and AG systems that balances the average inward confining force against the outward pressure-gradient and space-charge forces. The PTSX device confines one-component cesium ion plasmas for hundreds of milliseconds, which is equivalent to over 10 km of beam propagation.

  15. Production of intense negative hydrogen beams with polarized nuclei by selective neutralization of negative ions

    DOEpatents

    Hershcovitch, Ady

    1987-01-01

    A process for selectively neutralizing H.sup.- ions in a magnetic field to produce an intense negative hydrogen ion beam with spin polarized protons. Characteristic features of the process include providing a multi-ampere beam of H.sup.- ions that are intersected by a beam of laser light. Photodetachment is effected in a uniform magnetic field that is provided around the beam of H.sup.- ions to spin polarize the H.sup.- ions and produce first and second populations or groups of ions, having their respective proton spin aligned either with the magnetic field or opposite to it. The intersecting beam of laser light is directed to selectively neutralize a majority of the ions in only one population, or given spin polarized group of H.sup.- ions, without neutralizing the ions in the other group thereby forming a population of H.sup.- ions each of which has its proton spin down, and a second group or population of H.sup.o atoms having proton spin up. Finally, the two groups of ions are separated from each other by magnetically bending the group of H.sup.- ions away from the group of neutralized ions, thereby to form an intense H.sup.- ion beam that is directed toward a predetermined objective.

  16. Analysis of the dynamic behavior of an intense charged particle beam using the semigroup approach

    NASA Astrophysics Data System (ADS)

    Stafford, M. A.

    1985-05-01

    Dynamic models of a charged particle beam subject to external electromagnetic fields are cast into the abstract Cauchy problem form. Various applications of intense charged particle beams, i.e., beams whose self electromagnetic fields are significant, might require, or be enhanced by, the use of dynamic control constructed from suitably processed measurements of the state of the beam. This research provides a mathematical foundation for future engineering development of estimation and control designs for such beams. Beginning with the Vlasov equation, successively simpler models of intense beams are presented, along with their corresponding assumptions. Expression of a model in abstract Cauchy problem form is useful in determining whether the model is well posed. Solutions of well-posed problems can be expressed in terms of a one-parameter semigroup of linear operators. (The state transition matrix for a system of linear, ordinary, first-order, constant coefficient differential equations is a special case of such a semigroup.) The semigroup point of view allows the application of the rapidly maturing modern control theory of infinite-dimensional systems. An appropriate underlying Banach space is identified for a simple, but non-trivial, single degree of freedom model (the electrostatic approximation model), and the associated one-parameter semigroup of linear operators is characterized.

  17. The Intense Slow Positron Beam Facility at the NC State University PULSTAR Reactor

    SciTech Connect

    Hawari, Ayman I.; Moxom, Jeremy; Hathaway, Alfred G.; Brown, Benjamin; Xu, Jun

    2009-03-10

    An intense slow positron beam is in its early stages of operation at the 1-MW open-pool PULSTAR research reactor at North Carolina State University. The positron beam line is installed in a beam port that has a 30-cmx30-cm cross sectional view of the core. The positrons are created in a tungsten converter/moderator by pair-production using gamma rays produced in the reactor core and by neutron capture reactions in cadmium cladding surrounding the tungsten. Upon moderation, slow ({approx}3 eV) positrons that are emitted from the moderator are electrostatically extracted, focused and magnetically guided until they exit the reactor biological shield with 1-keV energy, approximately 3-cm beam diameter and an intensity exceeding 6x10{sup 8} positrons per second. A magnetic beam switch and transport system has been installed and tested that directs the beam into one of two spectrometers. The spectrometers are designed to implement state-of-the-art PALS and DBS techniques to perform positron and positronium annihilation studies of nanophases in matter.

  18. ECR (Electron Cyclotron Resonance) source for the HHIRF (Holifield Heavy Ion Research Facility) tandem accelerator

    SciTech Connect

    Olsen, D.K.; Alton, G.D.; Dowling, D.T.; Haynes, D.L.; Jones, C.M.; Juras, R.C.; Lane, S.N.; Meigs, M.J.; Mills, G.D.; Mosko, S.W.; Tatum, B.A.

    1990-01-01

    Electron Cyclotron Resonance, ECR, ion source technology has developed rapidly since the original pioneering work of R. Geller and his group at Grenoble in the early 1970s. These ion sources are capable of producing intense beams of highly charged positive ions and are used extensively for cyclotron injection, linac injection, and atomic physics research. In this paper, the advantages of using an ECR heavy-ion source in the terminal of the Holifield Heavy Ion Research Facility (HHIRF) 25-MV tandem accelerator is discussed. A possible ECR system for installation in the HHIRF tandem terminal is described.

  19. High intensity single bunch operation with heavy periodic transient beam loading in wide band rf cavities

    NASA Astrophysics Data System (ADS)

    Tamura, Fumihiko; Hotchi, Hideaki; Schnase, Alexander; Yoshii, Masahito; Yamamoto, Masanobu; Ohmori, Chihiro; Nomura, Masahiro; Toda, Makoto; Shimada, Taihei; Hasegawa, Katsushi; Hara, Keigo

    2015-09-01

    The rapid cycling synchrotron (RCS) in the Japan Proton Accelerator Research Complex (J-PARC) was originally designed to accelerate two high intensity bunches, while some of neutron experiments in the materials and life science experimental facility and a muon experiment using main ring beams require a single bunch operation mode, in which one of the two rf buckets is filled and the other is empty. The beam intensity in the single bunch operation has been limited by longitudinal beam losses due to the rf bucket distortions by the wake voltage of the odd harmonics (h =1 ,3 ,5 ) in the wide band magnetic alloy cavities. We installed an additional rf feedforward system to compensate the wake voltages of the odd harmonics (h =1 ,3 ,5 ). The additional system has a similar structure as the existing feedforward system for the even harmonics (h =2 ,4 ,6 ). We describe the function of the feedforward system for the odd harmonics, the commissioning methodology, and the commissioning results. The longitudinal beam losses during the single bunch acceleration disappeared with feedforward for the odd harmonics. We also confirmed that the beam quality in the single bunch acceleration are similar to that of the normal operation with two bunches. Thus, high intensity single bunch acceleration at the intensity of 2.3 ×1013 protons per bunch has been achieved in the J-PARC RCS. This article is a follow-up of our previous article, Phys. Rev. ST Accel. Beams 14, 051004 (2011). The feedforward system extension for single bunch operation was successful.

  20. Studies on a Q/A selector for the SECRAL electron cyclotron resonance ion source

    SciTech Connect

    Yang, Y.; Sun, L. T.; Feng, Y. C.; Fang, X.; Lu, W.; Zhang, W. H.; Cao, Y.; Zhang, X. Z.; Zhao, H. W.

    2014-08-15

    Electron cyclotron resonance ion sources are widely used in heavy ion accelerators in the world because they are capable of producing high current beams of highly charged ions. However, the design of the Q/A selector system for these devices is challenging, because it must have a sufficient ion resolution while controlling the beam emittance growth. Moreover, this system has to be matched for a wide range of ion beam species with different intensities. In this paper, research on the Q/A selector system at the SECRAL (Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou) platform both in experiment and simulation is presented. Based on this study, a new Q/A selector system has been designed for SECRAL II. The features of the new design including beam simulations are also presented.

  1. Studies on a Q/A selector for the SECRAL electron cyclotron resonance ion source.

    PubMed

    Yang, Y; Sun, L T; Feng, Y C; Fang, X; Lu, W; Zhang, W H; Cao, Y; Zhang, X Z; Zhao, H W

    2014-08-01

    Electron cyclotron resonance ion sources are widely used in heavy ion accelerators in the world because they are capable of producing high current beams of highly charged ions. However, the design of the Q/A selector system for these devices is challenging, because it must have a sufficient ion resolution while controlling the beam emittance growth. Moreover, this system has to be matched for a wide range of ion beam species with different intensities. In this paper, research on the Q/A selector system at the SECRAL (Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou) platform both in experiment and simulation is presented. Based on this study, a new Q/A selector system has been designed for SECRAL II. The features of the new design including beam simulations are also presented. PMID:25173256

  2. Parasitic slow extraction of extremely weak beam from a high-intensity proton rapid cycling synchrotron

    NASA Astrophysics Data System (ADS)

    Zou, Ye; Tang, Jingyu; Yang, Zheng; Jing, Hantao

    2014-02-01

    This paper proposes a novel method to extract extremely weak beam from a high-intensity proton rapid cycling synchrotron (RCS) in the parasitic mode, while maintaining the normal fast extraction. The usual slow extraction method from a synchrotron by employing third-order resonance cannot be applied in a high-intensity RCS due to a very short flat-top at the extraction energy and the strict control on beam loss. The proposed parasitic slow extraction method moves the beam to scrape a scattering foil prior to the fast beam extraction by employing either a local orbit bump or momentum deviation or their combination, so that the halo part of the beam will be scattered. A part of the scattered particles will be extracted from the RCS and guided to the experimental area. The slow extraction process can last about a few milliseconds before the beam is extracted by the fast extraction system. The method has been applied to the RCS of China Spallation Neutron Source. With 1.6 GeV in the extraction energy, 62.5 μA in the average current and 25 Hz in the repetition rate for the RCS, the proton intensity by the slow extraction method can be up to 2×104 protons per cycle or 5×105 protons per second. The extracted beam has also a good time structure of approximately uniform in a spill which is required for many applications such as detector tests. Detailed studies including the scattering effect in the foil, the local orbit bump by the bump magnets and dispersive orbit bump by modifying the RF pattern, the multi-particle simulations by ORBIT and TURTLE codes, and some technical features for the extraction magnets are presented.

  3. Cryogenic system upgrade for the National Superconducting Cyclotron Laboratory

    SciTech Connect

    A. McCartney; V. Ganni; H. Laumer; D. Arenius; J. Creel; W. Chronis; K. Davidson

    2002-05-10

    The National Superconducting Cyclotron Laboratory (NSCL) is a National Science Foundation supported facility, with additional support from Michigan State University (MSU). The facility consists of two superconducting cyclotrons and over fifty individual cryostats, each containing several superconducting magnets that are used in the beam transport system. The facility also has a superconducting ion source and a large superconducting spectrograph. To support this facility we operated two helium refrigerators producing approximate 900W at 4.5K. In July of 1999, construction of a new beam analysis system, the A1900, was started. The laboratory was reconfigured to couple the two cyclotrons in series to enable the facility to produce higher intensity radioactive beams than previously possible in the stand-alone mode. In addition, the helium distribution system was upgraded with new transfer lines and a new distribution box. The new requirements increased the refrigeration load to more than 1 KW at 4.5K. To support this increased cryogenic load, the existing two helium cryogenic plants, were at best, marginal in capacity. This would have required both plants to run at full capacity, maximum efficiency and availability. To achieve higher reliability, availability, and process transient capacity for magnet cool down and filling, a decision was made to obtain a larger cryogenic plant to support the new system. The following paper describes the important aspects and capabilities of the new cryogenic system to accomplish this goal.

  4. High intensity ion guides and purification techniques for low energy radioactive ion beams

    NASA Astrophysics Data System (ADS)

    Grévy, S.

    2016-06-01

    This report gives an overview of the different devices which can be used for the purification of high intensity low energy radioactive ion beams: high resolution magnetic separators (HRS), multi-reflection time-of-flight mass separators (MR-TOF-MS) and Penning traps (PT). An overview of HRS, existing or in development, and the methods to increase the resolving power are presented. The MR-TOF-MS of ISOLTRAP and other projects having been presented during this conference, only the main characteristics of such devices are discussed. Concerning the PT, intensively used to measure masses with high precisions, we will present the PIPERADE project which aims to provide pure beams of exotic nuclei with unprecedent intensities at the future DESIR/SPIRAL2 facility.

  5. Scaling to Ultra-High Intensities by High-Energy Petawatt Beam Combining

    SciTech Connect

    Siders, C W; Jovanovic, I; Crane, J; Rushford, M; Lucianetti, A; Barty, C J

    2006-06-23

    The output pulse energy from a single-aperture high-energy laser amplifier (e.g. fusion lasers such as NIF and LMJ) are critically limited by a number of factors including optical damage, which places an upper bound on the operating fluence; parasitic gain, which limits together with manufacturing costs the maximum aperture size to {approx} 40-cm; and non-linear phase effects which limits the peak intensity. For 20-ns narrow band pulses down to transform-limited sub-picosecond pulses, these limiters combine to yield 10-kJ to 1-kJ maximum pulse energies with up to petawatt peak power. For example, the Advanced Radiographic Capability (ARC) project at NIF is designed to provide kilo-Joule pulses from 0.75-ps to 50-ps, with peak focused intensity above 10{sup 19} W/cm{sup 2}. Using such a high-energy petawatt (HEPW) beamline as a modular unit, they discuss large-scale architectures for coherently combining multiple HEPW pulses from independent apertures, called CAPE (Coherent Addition of Pulses for Energy), to significantly increase the peak achievable focused intensity. Importantly, the maximum intensity achievable with CAPE increases non-linearly. Clearly, the total integrated energy grows linearly with the number of apertures N used. However, as CAPE combines beams in the focal plane by increasing the angular convergence to focus (i.e. the f-number decreases), the foal spot diameter scales inversely with N. Hence the peak intensity scales as N{sup 2}. Using design estimates for the focal spot size and output pulse energy (limited by damage fluence on the final compressor gratings) versus compressed pulse duration in the ARC system, Figure 2 shows the scaled focal spot intensity and total energy for various CAPE configurations from 1,2,4, ..., up to 192 total beams. They see from the fixture that the peak intensity for event modest 8 to 16 beam combinations reaches the 10{sup 21} to 10{sup 22} W/cm{sup 2} regime. With greater number of apertures, or with

  6. Experimental demonstration of tomographic slit technique for measurement of arbitrary intensity profiles of light beams

    NASA Astrophysics Data System (ADS)

    Soto, José; Rendón, Manuel; Martín, Manuel

    1997-10-01

    We demonstrate experimentally an optical imaging method that makes use of a slit to collect tomographic projection data of arbitrarily shaped light beams; a tomographic backprojection algorithm is then used to reconstruct the intensity profiles of these beams. Two different implementations of the method are presented. In one, a single slit is scanned and rotated in front of the laser beam. In the other, the sides of a polygonal slit, which is linearly displaced in a x-y plane perpendicular to the beam, are used to collect the data. This latter version is more suitable than the other for adaptation at micrometer-size scale. A mathematical justification is given here for the superior performance against laser-power fluctuations of the tomographic slit technique compared with the better-known tomographic knife-edge technique.

  7. Theoretical and Computational Investigation of Periodically Focused Intense Charged-Particle Beams

    SciTech Connect

    Chen, Chiping

    2013-06-26

    The purpose of this report is to summarize results of theoretical and computational investigations of periodically focused intense charged-particle beams in parameter regimes relevant to the development of advanced high-brightness, high-power accelerators for high-energy physics research. The breakthroughs and highlights in our research in the period from April 1, 2010 to March 30, 2013 were: a) Theory and simulation of adiabatic thermal Child-Langmuir flow; b) Particle-in-cell simulations of adiabatic thermal beams in periodic solenoidal focusing field; c)Dynamics of charged particles in an adiabatic thermal beam equilibrium in a periodic solenoidal focusing field; d) Training of undergraduate researchers and graduate student in accelerator and beam physics. A brief introduction and summary is presented. Detailed descriptions of research results are provided in an appendix of publications at the end of the report.

  8. Numerical studies of the Weibel Instability in Intense Charged Particle Beams with Large Energy Anisotropy

    NASA Astrophysics Data System (ADS)

    Lee, Wei-Li; Startsev, Edward A.; Davidson, Ronald C.

    2004-11-01

    In intense charged particle beams with large temperature anisotropy free energy is available to drive a transverse electromagnetic Weibel-type instability. The finite transverse geometry of the confined beam makes a detailed theoretical investigation difficult. In this paper the newly developed bEASt (beam eigenmode and spectra) code which solves the linearized Vlasov-Maxwell equations is used to investigate the detailed properties of the Weibel instability for a long charge bunch propagating through a cylindrical pipe of radius r_w. The stability analysis is carried out for azimuthally symmetric perturbations about a two-temperature thermal equilibrium distribution in the smooth-focusing approximation. To study the nonlinear stage of the instability, the Darwin model is being developed and incorporated into the Beam Equilibrium Stability and Transport(BEST) code.

  9. Review of intense-ion-beam propagation with a view toward measuring ion energy

    SciTech Connect

    Garcia, M.

    1982-08-25

    The subject of this review is intense ion beam propagation and the possibilities of measuring time dependent ion energy in the beam. Propagation effects discussed include charge separation, charge and current autoneutralization, electron thermalization and current neutralization decay. The interaction of a plasma beam with material obstacles, like collimators, and with transverse magnetic fields is also described. Depending on beam energy, density and pulse length, these interactions can include material ablation with plasmadynamic flow and undeflected propagation across transverse magnetic fields by a polarization drift. On the basis of this review I conclude that three diagnostics: a single floating potential probe, net current probes (Faraday cups) and a Rutherford scattering spectrometer appear capable of giving prompt, time dependent ion energy measurements.

  10. Super-intense femtosecond multichannel laser system with coherent beam combining

    NASA Astrophysics Data System (ADS)

    Bagayev, S. N.; Trunov, V. I.; Pestryakov, E. V.; Frolov, S. A.; Leshchenko, V. E.; Kokh, A. E.; Vasiliev, V. A.

    2014-07-01

    The conceptual design of ultra-high intensity multichannel laser system with coherent beam combining is presented. Design of 1 PW and 10 PW laser channels with pulse repetition rate of 10 Hz based on optical parametric amplification in LBO crystals is considered. Requirements of the most critical pulse parameters for high efficiency coherent beam combining and their dependence on the number of channels is analyzed. Experimentally coherent beam combining of parametrically amplified compressed femtosecond pulses is demonstrated for the first time. Original two-loop relative timing jitter active stabilization scheme is proposed and experimentally investigated. 97% coherent beam combining efficiency is achieved with 110 as relative timing jitter.

  11. A low-temperature growth process of GaAs by electron-cyclotron-resonance plasma-excited molecular-beam-epitaxy (ECR-MBE)

    NASA Astrophysics Data System (ADS)

    Kondo, Naoto; Nanishi, Yasushi

    1988-09-01

    Taking advantage of plasma excitation, surface cleaning and growth process are realized at low temperatures by electron-cyclotron-resonance (ECR) plasma-excited molecular-beam-epitaxy (MBE). Prior to growth, substrates are cleaned by exposure to hydrogen plasma at temperatures ranging from 300 to 550°C. Arsine gas is introduced and cracked in an ECR plasma generation chamber. Gallium is supplied either as trimethylgallium (TMG) or as metallic Ga. Epitaxial films are successfully grown at substrate temperatures low as 430°C for the TMG-arsine system and 350°C for the metallic Ga-arsine system. The growth rate for the TMG-arsine system is found to be governed by a balance between TMG decomposition and surface atom desorption. By contrast, the metallic Ga-arsine system is only governed by the desorption process. Exposure to plasma is found to promote desorption of atoms migrating on the substrate surface. The interface between the substrate and the epitaxial layer produced by the ECR-MBE process is found to be clean without piling up of impurity.

  12. Neutron spectra produced by 30, 35 and 40 MeV proton beams at KIRAMS MC-50 cyclotron with a thick beryllium target

    NASA Astrophysics Data System (ADS)

    Shin, Jae Won; Bak, Sang-In; Ham, Cheolmin; In, Eun Jin; Kim, Do Yoon; Min, Kyung Joo; Zhou, Yujie; Park, Tae-Sun; Hong, Seung-Woo; Bhoraskar, V. N.

    2015-10-01

    Neutrons over a wide range of energies are produced by bombarding a 1.05 cm thick beryllium target with protons of different energies delivered by the MC-50 Cyclotron of the Korea Institute of Radiological Medical Sciences (KIRAMS). The neutron flux Φ(En) versus neutron energy En, produced by protons of 30, 35, and 40 MeV energies, was obtained by using the GEANT4 code with a data-based hadronic model. For the experimental validation of the simulated neutron spectra, a number of pure aluminum and iron oxide samples were irradiated with the neutrons produced by 30, 35, and 40 MeV protons at 20 μA beam current. The gamma-ray activities of 24Na and 56Mn produced, respectively, through 27Al(n,α)24Na and 56Fe(n,p)56Mn reactions were measured by a HPGe detector. The neutron flux Φ(En) at each neutron energy from the simulation was multiplied with the evaluated cross-sections σ(En) of the respective nuclear reaction, and the summation ∑ Φ(En) σ(En) was calculated over the neutron spectrum for each proton energy of 30, 35, and 40 MeV. The measured gamma-ray activities of 24Na and 56Mn were found in good agreement with the activities estimated by using the summed values of ∑ Φ(En) σ(En) along with other parameters in a neutron activation method.

  13. Beam orientation optimization for intensity modulated radiation therapy using adaptive l2,1-minimization

    NASA Astrophysics Data System (ADS)

    Jia, Xun; Men, Chunhua; Lou, Yifei; Jiang, Steve B.

    2011-10-01

    Beam orientation optimization (BOO) is a key component in the process of intensity modulated radiation therapy treatment planning. It determines to what degree one can achieve a good treatment plan in the subsequent plan optimization process. In this paper, we have developed a BOO algorithm via adaptive l2, 1-minimization. Specifically, we introduce a sparsity objective function term into our model which contains weighting factors for each beam angle adaptively adjusted during the optimization process. Such an objective function favors a small number of beam angles. By optimizing a total objective function consisting of a dosimetric term and the sparsity term, we are able to identify unimportant beam angles and gradually remove them without largely sacrificing the dosimetric objective. In one typical prostate case, the convergence property of our algorithm, as well as how beam angles are selected during the optimization process, is demonstrated. Fluence map optimization (FMO) is then performed based on the optimized beam angles. The resulting plan quality is presented and is found to be better than that of equiangular beam orientations. We have further systematically validated our algorithm in the contexts of 5-9 coplanar beams for five prostate cases and one head and neck case. For each case, the final FMO objective function value is used to compare the optimized beam orientations with the equiangular ones. It is found that, in the majority of cases tested, our BOO algorithm leads to beam configurations which attain lower FMO objective function values than those of corresponding equiangular cases, indicating the effectiveness of our BOO algorithm. Superior plan qualities are also demonstrated by comparing DVH curves between BOO plans and equiangular plans.

  14. Grating monochromator for electron cyclotron resonance ion source operation.

    PubMed

    Muto, Hideshi; Ohshiro, Yukimitsu; Yamaka, Shouichi; Watanabe, Shin-ichi; Oyaizu, Michihiro; Kubono, Shigeru; Yamaguchi, Hidetoshi; Kase, Masayuki; Hattori, Toshiyuki; Shimoura, Susumu

    2013-07-01

    Recently, we started to observe optical line spectra from an ECR plasma using a grating monochromator with a photomultiplier. The light intensity of line spectrum from the ECR plasma had a strong correlation with ion beam intensity measured by a magnetic mass analyzer. This correlation is a significant information for beam tuning because it allows the extraction of the desired ion species from the ECR plasma. Separation of ion species of the same charge to mass ratio with an electromagnetic mass analyzer is known to be an exceptionally complex process, but this research gives new insights into its simplification. In this paper, the grating monochromator method for beam tuning of a Hyper-ECR ion source as an injector for RIKEN azimuthal varying field (AVF) cyclotron is described. PMID:23902055

  15. Controlling precise magnetic field configuration around electron cyclotron resonance zone for enhancing plasma parameters and beam current

    SciTech Connect

    Yano, Keisuke Kurisu, Yosuke; Nozaki, Dai; Kimura, Daiju; Imai, Youta; Kumakura, Sho; Sato, Fuminobu; Kato, Yushi; Iida, Toshiyuki

    2014-02-15

    Multi-charged ion source which has wide operating conditions is required in various application fields. We have constructed tandem type ECR ion source (ECRIS); one of the features of its main stage is an additional coil for controlling magnetic field distribution around the mirror bottom precisely. Here the effect of magnetic field variation caused by the additional coil is experimentally considered in terms of plasma parameters and beam current as the first investigation of the main stage plasma. Furthermore, behavior of magnetic lines of force flowing from the ECR zone is calculated, and is compared with measurement results aiming for better understanding of interrelationship between plasma production and ion beam generation on the ECRIS.

  16. Three-dimensional numerical studies of the temperature anisotropy instability in intense charged particle beams

    NASA Astrophysics Data System (ADS)

    Startsev, Edward A.; Davidson, Ronald C.; Qin, Hong

    2005-05-01

    In neutral plasmas with a uniform magnetic field and strongly anisotropic distribution function (T∥/T⊥≪1) an electrostatic Harris-type collective instability may develop if the plasma is sufficiently dense. Such anisotropies develop naturally in accelerators, and a similar instability may lead to a deterioration of the beam quality in a one-component nonneutral charged particle beam. The instability may also lead to an increase in the longitudinal velocity spread, which would make the focusing of the beam difficult and impose a limit on the minimum spot size achievable in heavy ion fusion experiments. This paper reports the results of recent numerical studies of the temperature anisotropy instability using the newly developed Beam Eigenmodes And Spectra (bEASt) code for space-charge-dominated, low-emittance beams with large tune depression (ν/ν0≪1). Such high-intensity beams are relevant to next-step experiments such as the Integrated Beam Experiment (IBX), which would serve as proof-of-principal experiment for heavy-ion fusion.

  17. Formation of plasma and ion flux on a target, irradiated by an intense electron beam

    SciTech Connect

    Engelko, Vladimir; Mueller, Georg

    2005-07-01

    Theoretical consideration shows that under the influence of an intense electron beam, first, an ion flux and then plasma are formed on the surface of a target. The target plasma is created when the density of the ion flux achieves a certain limiting value. The time necessary for the plasma formation depends on the beam current density and the efficiency of gas desorption and ionization. This time is few microseconds under typical vacuum conditions of about 5.0x10{sup -5} mbar, electron-beam current density in the range of 10 A/cm{sup 2}, and kinetic energy of electrons in the range of 100 keV. When the density of the ion flux reaches a limiting value the beam potential decreases to a level, which is half of the initial one. A transient layer is formed between the plasma boundary and the electron beam. For conditions mentioned above its length are few centimeters. The target plasma expands into the beam drift region, with a velocity increasing in time. The expansion of the target plasma is the main reason for neutralization of the electron-beam space charge.

  18. New Capabilities for Modeling Intense Beams in Heavy Ion Fusion Drivers

    SciTech Connect

    Friedman, A; Barnard, J J; Bieniosek, F M; Celata, C M; Cohen, R H; Davidson, R C; Grote, D P; Haber, I; Henestroza, E; Lee, E P; Lund, S M; Qin, H; Sharp, W M; Startsev, E; Vay, J L

    2003-09-09

    Significant advances have been made in modeling the intense beams of heavy-ion beam-driven Inertial Fusion Energy (Heavy Ion Fusion). In this paper, a roadmap for a validated, predictive driver simulation capability, building on improved codes and experimental diagnostics, is presented, as are examples of progress. The Mesh Refinement and Particle-in-Cell methods were integrated in the WARP code; this capability supported an injector experiment that determined the achievable current rise time, in good agreement with calculations. In a complementary effort, a new injector approach based on the merging of {approx}100 small beamlets was simulated, its basic feasibility established, and an experimental test designed. Time-dependent 3D simulations of the High Current Experiment (HCX) were performed, yielding voltage waveforms for an upcoming study of bunch-end control. Studies of collective beam modes which must be taken into account in driver designs were carried out. The value of using experimental data to tomographically ''synthesize'' a 4D beam particle distribution and so initialize a simulation was established; this work motivated further development of new diagnostics which yield 3D projections of the beam phase space. Other developments, including improved modeling of ion beam focusing and transport through the fusion chamber environment and onto the target, and of stray electrons and their effects on ion beams, are briefly noted.

  19. Nonlinear Plasma Waves Excitation by Intense Ion Beams in Background Plasma

    SciTech Connect

    Igor D. Kaganovich; Edward A. Startsev; Ronald C. Davidson

    2004-04-15

    Plasma neutralization of an intense ion pulse is of interest for many applications, including plasma lenses, heavy ion fusion, cosmic ray propagation, etc. An analytical electron fluid model has been developed to describe the plasma response to a propagating ion beam. The model predicts very good charge neutralization during quasi-steady-state propagation, provided the beam pulse duration {tau}{sub b} is much longer than the electron plasma period 2{pi}/{omega}{sub p}, where {omega}{sub p} = (4{pi}e{sup 2}n{sub p}/m){sup 1/2} is the electron plasma frequency and n{sub p} is the background plasma density. In the opposite limit, the beam pulse excites large-amplitude plasma waves. If the beam density is larger than the background plasma density, the plasma waves break. Theoretical predictions are compared with the results of calculations utilizing a particle-in-cell (PIC) code. The cold electron fluid results agree well with the PIC simulations for ion beam propagation through a background plasma. The reduced fluid description derived in this paper can provide an important benchmark for numerical codes and yield scaling relations for different beam and plasma parameters. The visualization of numerical simulation data shows complex collective phenomena during beam entry and exit from the plasma.

  20. ECR (Electron Cyclotron Resonance) ion sources for cyclotrons

    SciTech Connect

    Lyneis, C.M.

    1986-10-01

    In the last decade ECR (Electron Cyclotron Resonance) ion sources have evolved from a single large, power consuming, complex prototype into a variety of compact, simple, reliable, efficient, high performance sources of high charge state ions for accelerators and atomic physics. The coupling of ECR sources to cyclotrons has resulted in significant performance gains in energy, intensity, reliability, and variety of ion species. Seven ECR sources are in regular operation with cyclotrons and numerous other projects are under development or in the planning stag. At least four laboratories have ECR sources dedicated for atomic physics research and other atomic physics programs share ECR sources with cyclotrons. An ECR source is now installed on the injector for the CERN SPS synchrotron to accelerate O/sup 8 +/ to relativistic energies. A project is underway at Argonne to couple an ECR source to a superconducting heavy-ion linac. Although tremendous progress has been made, the field of ECR sources is still a relatively young technology and there is still the potential for further advances both in source development and understanding of the plasma physics. The development of ECR sources is reviewed. The important physics mechanisms which come into play in the operation of ECR Sources are discussed, along with various models for charge state distributions (CSD). The design and performance of several ECR sources are compared. The 88-Inch Cyclotron and the LBL ECR is used as an example of cyclotron+ECR operation. The future of ECR sources is considered.

  1. Measurements of radiobiological effectiveness in the 85 MeV proton beam produced at the cyclotron CYCLONE of Louvain-la-Neuve, Belgium

    SciTech Connect

    Gueulette, J.; Gregoire, V.; Octave-Prignot, M.; Wambersie, A.

    1996-01-01

    The RBE of the 85 MeV proton beam produced at the cyclotron of Louvain-la-Neuve using {sup 60}Co {gamma} rays as the reference radiation was determined for survival of Chinese hamster ovary cells in vitro and for intestinal crypt regeneration in mice in vivo. Cell survival curves determined at different depths yielded, for a surviving fraction (SF) of 0.01, RBE values of 1.11 {+-} 0.05 at the initial plateau of the unmodulated beam, 1.10 {+-} 0.03 at the middle of a 0.5-cm spread-out Bragg peak (SOBP), 1.03 {+-} 0.03 at the beginning of a 3-cm SOBP and 1.07 {+-} 0.03 at the end of a 3-cm SOBP. The highest RBE values were obtained at the middle of the 0.5-cm SOBP and at the end of the 3-cm SOBP (RBE = 1.22 and 1.16, respectively, at SF = 0.5), although the variations are not statistically significant. Irradiations with 3-Gy fractions separated by an interval of 3.5 h yielded RBEs of 1.11 {+-} 0.30 and 0.90 {+-} 0.32 at the initial plateau and at the middle of the 0.5-cm SOBP, respectively. Irradiations of mice at the middle of the 3-cm SOBP yielded an RBE of 1.08 {+-} 0.03 for 20 regenerated crypts at a proton dose of 12.3 Gy. 18 refs., 4 figs., 1 tab.

  2. Soft x-ray intensity profile measurements of electron cyclotron heated plasmas using semiconductor detector arrays in GAMMA 10 tandem mirror

    SciTech Connect

    Minami, R. Imai, T.; Kariya, T.; Numakura, T.; Eguchi, T.; Kawarasaki, R.; Nakazawa, K.; Kato, T.; Sato, F.; Nanzai, H.; Uehara, M.; Endo, Y.; Ichimura, M.

    2014-11-15

    Temporally and spatially resolved soft x-ray analyses of electron cyclotron heated plasmas are carried out by using semiconductor detector arrays in the GAMMA 10 tandem mirror. The detector array has 16-channel for the measurements of plasma x-ray profiles so as to make x-ray tomographic reconstructions. The characteristics of the detector array make it possible to obtain spatially resolved plasma electron temperatures down to a few tens eV and investigate various magnetohydrodynamic activities. High power electron cyclotron heating experiment for the central-cell region in GAMMA 10 has been started in order to reduce the electron drag by increasing the electron temperature.

  3. Theory of relativistic cyclotron masers

    NASA Astrophysics Data System (ADS)

    Nusinovich, G. S.; Latham, P. E.; Dumbrajs, O.

    1995-07-01

    In this paper we have made an attempt to review the present status of the theory of cyclotron masers with relativistic electron beams. After discussing the basic features of electron-cyclotron radiation under conditions of normal and anomalous Doppler frequency shifts, we consider particle deceleration by a constant amplitude electromagnetic wave in a constant magnetic field using the formalism developed earlier for cyclotron autoresonance acceleration of electrons. An optimal cyclotron resonance mismatch was found that corresponds to the possibility of complete deceleration of relativistic electrons. Then, interaction of relativistic electrons with resonator fields is considered and the efficiency increase due to electron prebunching is demonstrated in a simple model. Since an efficient interaction of relativistic electrons with the large amplitude electromagnetic field of a resonator occurs at a short distance, where electrons make a small number of electron orbits, the issue of the simultaneous interaction of electrons with the field at several cyclotron harmonics is discussed. Finally, we consider deceleration of a prebunched electron beam by a traveling electromagnetic wave in a tapered magnetic field. This simple modeling is illustrated with a number of simulations of relativistic gyroklystrons and gyrotwistrons (gyrodevices in which the bunching cavity of the gyroklystron is combined with the output waveguide of the gyro-traveling-wave-tube).

  4. Production of intense attosecond vector beam pulse trains based on harmonics

    NASA Astrophysics Data System (ADS)

    Han, Yu-Jing; Liao, Guo-Qian; Chen, Li-Ming; Li, Yu-Tong; Wang, Wei-Min; Zhang, Jie

    2015-11-01

    We provide the first report on the harmonics generated by an intense femtosecond vector beam that is normally incident on a solid target. By using 2D particle-in-cell (PIC) codes, we observe the third and the fifth harmonic signals with the same vector structure as the driving beam, and obtain an attosecond vector beam pulse train. We also show that the conversion efficiencies of the third and the fifth harmonics reach their maxima for a plasma density of four times the critical density due to the plasma resonating with the driving force. This method provides a new means of generating intense extreme ultraviolet (XUV) vector beams via ultra-intense laser-driven harmonics. Project supported by the National Basic Research Program of China (Grant Nos. 2013CBA01501 and 2013CBA01504), the National Key Scientific Instrument and Equipment Development Project of China (Grant No. 2012YQ120047), Chinese Academy of Science Key Program, the National Natural Science of China (Grant Nos. 11135012 and 11375262), and the Project of Shandong Province Higher Educational Science and Technology Program, China (Grant No. J11LA52).

  5. Intense laser beams; Proceedings of the Meeting, Los Angeles, CA, Jan. 23, 24, 1992

    NASA Technical Reports Server (NTRS)

    Wade, Richard C. (Editor); Ulrich, Peter B. (Editor)

    1992-01-01

    Various papers on intense laser beams are presented. Individual topics addressed include: novel methods of copper vapor laser excitation, UCLA IR FEL, lasing characteristics of a large-bore copper vapor laser (CVL), copper density measurement of a large-bore CVL, high-power XeCl excimer laser, solid state direct-drive circuit for pumping gas lasers, united energy model for FELs, intensity and frequency instabilities in double-mode CO2 lasers, comparison of output power stabilities of CO and CO2 lasers, increasing efficiency of sealed-off CO lasers, thermal effects in singlet delta oxygen generation, optical extraction from the chemical oxygen-iodine laser medium, generation and laser diagnostic analysis of bismuth fluoride. Also discussed are: high-Q resonator design for an HF overtone chemical lasers, improved coatings for HF overtone lasers, scaled atmospheric blooming experiment, simulation on producing conjugate field using deformable mirrors, paraxial theory of amplitude correction, potential capabilities of adaptive optical systems in the atmosphere, power beaming research at NASA, system evaluations of laser power beaming options, performance projections for laser beam power to space, independent assessment of laser power beaming options, removal of atmospheric CFCs by lasers, efficiency of vaporization cutting by CVL.

  6. Monoenergetic beams of relativistic electrons from intense laser-plasma interactions.

    PubMed

    Mangles, S P D; Murphy, C D; Najmudin, Z; Thomas, A G R; Collier, J L; Dangor, A E; Divall, E J; Foster, P S; Gallacher, J G; Hooker, C J; Jaroszynski, D A; Langley, A J; Mori, W B; Norreys, P A; Tsung, F S; Viskup, R; Walton, B R; Krushelnick, K

    2004-09-30

    High-power lasers that fit into a university-scale laboratory can now reach focused intensities of more than 10(19) W cm(-2) at high repetition rates. Such lasers are capable of producing beams of energetic electrons, protons and gamma-rays. Relativistic electrons are generated through the breaking of large-amplitude relativistic plasma waves created in the wake of the laser pulse as it propagates through a plasma, or through a direct interaction between the laser field and the electrons in the plasma. However, the electron beams produced from previous laser-plasma experiments have a large energy spread, limiting their use for potential applications. Here we report high-resolution energy measurements of the electron beams produced from intense laser-plasma interactions, showing that--under particular plasma conditions--it is possible to generate beams of relativistic electrons with low divergence and a small energy spread (less than three per cent). The monoenergetic features were observed in the electron energy spectrum for plasma densities just above a threshold required for breaking of the plasma wave. These features were observed consistently in the electron spectrum, although the energy of the beam was observed to vary from shot to shot. If the issue of energy reproducibility can be addressed, it should be possible to generate ultrashort monoenergetic electron bunches of tunable energy, holding great promise for the future development of 'table-top' particle accelerators. PMID:15457251

  7. Early Beam Injection Scheme for the Fermilab Booster: A Path for Intensity Upgrade

    SciTech Connect

    Bhat, C. M.

    2015-10-28

    Over the past decade, Fermilab has focused efforts on the intensity frontier physics and is committed to increase the average beam power delivered to the neutrino and muon programs substantially. Many upgrades to the existing injector accelerators, namely, the current 400 MeV LINAC and the Booster, are in progress under the Proton Improvement Plan (PIP). Proton Improvement Plan-II (PIP-II) proposes to replace the existing 400 MeV LINAC by a new 800 MeV LINAC, as an injector to the Booster which will increase Booster output power by nearly a factor of two from the PIP design value by the end of its completion. In any case, the Fermilab Booster is going to play a very significant role for nearly next two decades. In this context, I have developed and investigated a new beam injection scheme called "early injection scheme" (EIS) for the Booster with the goal to significantly increase the beam intensity output from the Booster thereby increasing the beam power to the HEP experiments even before PIP-II era. The scheme, if implemented, will also help improve the slip-stacking efficiency in the MI/RR. Here I present results from recent simulations, beam studies, current status and future plans for the new scheme.

  8. Relative phase interactions of two copropagating laser beams in underdense plasmas at different intensities and spot sizes

    SciTech Connect

    Mahdy, A. I.

    2010-06-15

    The mutual interactions of two copropagating laser beams at a relative phase are studied using a two-dimensional fluid code. The interactions are investigated in underdense plasma at selected beam configurations and beam parameters for two separate nonlinearities, i.e., the ponderomotive and the relativistic nonlinearity. The selected beam configurations are introduced by different initial transverse spot size perturbations (finite and infinite) and different initial transversal intensity distributions (nonuniform and uniform) over those spot sizes and the selected beam parameters are given by different initial beam intensities relevant to each nonlinearity. In the ponderomotive nonlinearity, simulation results show that no mutual interactions are demonstrated between the copropagating beams regardless of the initial beam configurations and parameters. In nonlinear relativistic simulations, the mutual interactions between the beams are clearly observed, a mutual repulsion is formed in the presence of initial intensities that are nonuniformly distributed over finite spot sizes, and an effective strongly modulated mutual attraction takes places in the presence of initial intensities that are uniformly distributed over infinite spot sizes. Moreover, it is found in these simulations that increasing the initial beam intensities improves the attraction properties between the copropagationg beams.

  9. Development of CNS Active Target for Deuteron Induced Reactions with High Intensity Exotic Beam

    NASA Astrophysics Data System (ADS)

    Ota, Shinsuke; Tokieda, H.; Lee, C. S.; Kojima, R.; Watanabe, Y. N.; Corsi, A.; Dozono, M.; Gibelin, J.; Hashimoto, T.; Kawabata, T.; Kawase, S.; Kubono, S.; Kubota, Y.; Maeda, Y.; Matsubara, H.; Matsuda, Y.; Michimasa, S.; Nakao, T.; Nishi, T.; Obertelli, A.; Otsu, H.; Santamaria, C.; Sasano, M.; Takaki, M.; Tanaka, Y.; Leung, T.; Uesaka, T.; Yako, K.; Yamaguchi, H.; Zenihiro, J.; Takada, E.

    An active target system called CAT, has been developed aiming at the measurement of deuteron induced reactions with high intensity beams in inverse kinematics. The CAT consists of a time projection chamber using THGEM and an array of Si detectors or NaI scintilators. The effective gain for the recoil particle is deisgned to be 5 - 10 × 103, while one for the beam is reduced by 102 using mesh grid to match the amplified signal to the dynamic range same as the one for recoil particle. The structure of CAT and the effect of the mesh grid are reported.

  10. Investigation on the Influence of Different Laser Beam Intensity Distributions on Keyhole Geometry During Laser Welding

    NASA Astrophysics Data System (ADS)

    Volpp, J.

    An analytical quasi-static model of the keyhole during laser deep penetration welding is introduced. This model is used to calculate the keyhole geometry depending on spatial laser beam intensity. Keyhole shapes can be found solving the energy and pressure equations. All necessary physical effects like Fresnel and plasma absorption, heat conduction and vaporization are implemented in the model. For evaluation a Gaussian and a top hat beam profile were used. Experimental measurements of the keyhole shape using copper inlays in aluminum base material show good agreement with the results of the modeling.

  11. Intense ion beams as a tool for opacity measurements in warm dense matter

    SciTech Connect

    Abdallah, Joseph; Tauschwiz, An; Jacoby, J; Maruhn, J A; Novikov, V G; Tauschwitz, A; Onkels, E; Wittle, K; Rosmej, F B; Schott, R

    2009-01-01

    Opacity measurements in warm dense matter (WDM) provide a valuable benchmark for the diverging theoretical models in this regime. Heating of thin foils with intense heavy-ion beams allows one to create isolated samples of warm dense matter suitable for experimental determination of frequency-dependent opacities. A prerequisite for the measurements is the isothermal expansion of the heated foil. Hydrodynamic simulations predict that this condition is fulfilled. The analysis shows that existing ion-beam accelerators are capable to contribute to this field of research.

  12. Nonlinear d--ta-f Simulation Studies of Intense Charged Particle Beams with Large Temperature Anisotropy

    SciTech Connect

    Edward A. Startsev; Ronald C. Davidson; Hong Qin

    2002-05-07

    In this paper, a 3-D nonlinear perturbative particle simulation code (BEST) [H. Qin, R.C. Davidson and W.W. Lee, Physical Review Special Topics on Accelerators and Beams 3 (2000) 084401] is used to systematically study the stability properties of intense nonneutral charged particle beams with large temperature anisotropy (T{sub {perpendicular}b} >> T{sub {parallel}b}). The most unstable modes are identified, and their eigen frequencies, radial mode structure, and nonlinear dynamics are determined for axisymmetric perturbations with {partial_derivative}/{partial_derivative}{theta} = 0.

  13. Shaping of spherical light intensity based on the interference of tightly focused beams with different polarizations

    NASA Astrophysics Data System (ADS)

    Khonina, Svetlana N.; Ustinov, Andrey V.; Volotovsky, Sergey G.

    2014-08-01

    We consider the shaping of spherical intensity distributions based on the interference of counter-propagating tightly focused vortex beams with different polarizations. The formation of 3D distributions is performed using a simple method of optimization of the width and position of the single annular aperture. The optimum parameters for the narrow aperture are calculated analytically. In addition the wide aperture parameters are numerically adjusted. It is shown that depending on the polarization, the additional vortex phase and/or phase shift in the beams allow to form either solid light balls or light spheres of subwavelength radius. They consist of the various electric field components.

  14. The calculation of the dynamics of interaction between intense electron beams and dielectrics

    SciTech Connect

    Milyavskii, V.V.; Skvortsov, V.A.

    1995-09-01

    A mathematical model is constructed and a numerical investigation performed of the interaction between an intense relativistic electron beam and a solid high-molecular dielectric. The model is based on the equations of mechanics of continuum, electrodynamics, and kinetics, describing the accumulation and relaxation of space charge and shock-wave processes, as well as the evolution of electric field in the sample. A semiempirical procedure is proposed for the calculation of energy deposition by an electron beam in a target in the presence of a nonuniform electric field.

  15. Theory of electron-cyclotron-resonance laser accelerators

    SciTech Connect

    Chen, C. )

    1992-11-15

    The cyclotron-resonance laser (CRL) accelerator is a novel concept of accelerating continuous charged-particle beams to moderately or highly relativistic energies. This paper discusses prospects and limitations of this concept. In particular, the nonlinear coupling of an intense traveling electromagnetic wave with an electron beam in a guide magnetic field is studied, and the effects of wave dispersion on particle acceleration are analyzed. For a tenuous beam, it is shown in a single-particle theory that the maximum energy gain and the maximum acceleration distance for the beam electrons in CRL accelerators with optimal magnetic taper exhibit power-law scaling on the degree of wave dispersion (measured by the parameter [omega]/[ital ck][sub [parallel

  16. CT to Cone-beam CT Deformable Registration With Simultaneous Intensity Correction

    PubMed Central

    Zhen, Xin; Gu, Xuejun; Yan, Hao; Zhou, Linghong; Jia, Xun; Jiang, Steve B.

    2012-01-01

    Computed tomography (CT) to cone-beam computed tomography (CBCT) deformable image registration (DIR) is a crucial step in adaptive radiation therapy. Current intensity-based registration algorithms, such as demons, may fail in the context of CT-CBCT DIR because of inconsistent intensities between the two modalities. In this paper, we propose a variant of demons, called Deformation with Intensity Simultaneously Corrected (DISC), to deal with CT-CBCT DIR. DISC distinguishes itself from the original demons algorithm by performing an adaptive intensity correction step on the CBCT image at every iteration step of the demons registration. Specifically, the intensity correction of a voxel in CBCT is achieved by matching the first and the second moments of the voxel intensities inside a patch around the voxel with those on the CT image. It is expected that such a strategy can remove artifacts in the CBCT image, as well as ensuring the intensity consistency between the two modalities. DISC is implemented on computer graphics processing units (GPUs) in compute unified device architecture (CUDA) programming environment. The performance of DISC is evaluated on a simulated patient case and six clinical head-and-neck cancer patient data. It is found that DISC is robust against the CBCT artifacts and intensity inconsistency and significantly improves the registration accuracy when compared with the original demons. PMID:23032638

  17. Nonlinear resonance and envelope instability of intense beam in axial symmetric periodic channel

    NASA Astrophysics Data System (ADS)

    Li, Chao; Liu, Zhicong; Zhao, Yaliang; Qin, Qing

    2016-03-01

    When an intense charged particle beam propagates through a given periodic focusing channel, it will experience the phenomena of nonlinear resonance, collective instability or chaotic motion with different conditions. In this paper, the collective envelope instability mechanisms are studied for symmetric beam propagation in an axially symmetric periodic channel. The beam is characterized as collectively stable if there exists a stable fixed point (SFP) located at the matched beam condition (rm , 0) in (r ,pr) phase space. It is found that the well-known collective envelope instability is dynamically related to the period-two orbits bifurcation of the matched SFP, meanwhile the unique stable SFP turns into an unstable saddle-node, surrounded by 1/2 resonance islands. However, higher orders of resonance (l / n, n > 2) coming from period-n bifurcation will not lead to collective beam instability because a new SFP emerges immediately upon the bifurcation process. The orders of SFP bifurcation is numerically depicted by the envelope tune ν=ϕ/360, where ϕ is the eigenphase of the Poincar e ´ tangent map T(s) in one focusing period at SFP, as functions of depressed phase advance. With strong space charge, due to these resonances from SFP bifurcation could be overlapped, mismatched beam would even show chaotic motion. For specific parameters, regular orbits, resonance islands, chaotic regions formed by resonance overlapping are clearly depicted with frequency analysis and Lyapunov spectral exponents, a method that may prove useful when extended to higher phase-space dimensions.

  18. Compact energy selector for use with intense, short-pulse laser produced proton beams

    NASA Astrophysics Data System (ADS)

    Hazi, Andrew; Chen, Hui; Perez, Frederic; Marley, Edward; Park, Jaebum; Williams, Jackson; Vassura, Laura; Fuchs, Julien; Chen, Sophia; Shepherd, Ronnie

    2012-10-01

    Irradiation of thin solid targets with short, intense laser pulses produces energetic charged particles. The proton and ion beams generated from such laser-plasma interactions have several attractive features, but usually exhibit a broad energy distribution extending up to tens of MeV. However for some applications, such as energy-loss measurements in plasmas or injection into high-energy accelerators, quasi-mono energetic beams are preferred [1]. We have designed, built and tested a small (9 x 7 x 5 cm^3) energy selector for use with laser-produced proton beams in beam-plasma interaction experiments that utilize multiple laser beams. The device uses permanent magnets in a dipole configuration, with a fixed entrance aperture and an adjustable exit slit to select a narrow portion of the broad energy distribution in the beam. The energy selector was tested in a recent experiment at the Titan laser at Livermore. Sample data from the experiment and simulations of the device's characteristics will be presented. [4pt] [1] T. Toncian, et al., ``Ultrafast Laser--Driven Microlens to Focus and Energy-Select Mega--Electron Volt Protons,'' Science, 312, 410 (2006).

  19. Novel neutralized-beam intense neutron source for fusion technology development

    SciTech Connect

    Osher, J.E.; Perkins, L.J.

    1983-07-08

    We describe a neutralized-beam intense neutron source (NBINS) as a relevant application of fusion technology for the type of high-current ion sources and neutral beamlines now being developed for heating and fueling of magnetic-fusion-energy confinement systems. This near-term application would support parallel development of highly reliable steady-state higher-voltage neutral D/sup 0/ and T/sup 0/ beams and provide a relatively inexpensive source of fusion neutrons for materials testing at up to reactor-like wall conditions. Beam-target examples described incude a 50-A mixed D-T total (ions plus neutrals) space-charge-neutralized beam at 120 keV incident on a liquid Li drive-in target, or a 50-A T/sup 0/ + T/sup +/ space-charge-neutralized beam incident on either a LiD or gas D/sub 2/ target with calculated 14-MeV neutron yields of 2 x 10/sup 15//s, 7 x 10/sup 15//s, or 1.6 x 10/sup 16//s, respectively. The severe local heat loading on the target surface is expected to limit the allowed beam focus and minimum target size to greater than or equal to 25 cm/sup 2/.

  20. Multiple reflection high-energy electron diffraction beam intensity measurement system

    NASA Technical Reports Server (NTRS)

    Resh, J. S.; Jamison, K. D.; Strozier, J.; Ignatiev, A.

    1990-01-01

    A video-based analysis system for reflection high-energy electron diffraction (RHEED) is described which simultaneously measures the intensities and profiles of multiple diffraction beams. This system is used to record real-time RHEED intensity oscillations for layer-by-layer epitaxial growth. Fast Fourier transform analysis of the oscillation data is used to directly determine the growth rate and to accurately obtain phase information about the oscillations. This system is demonstrated and compared to other methods of recording RHEED oscillation data.