Science.gov

Sample records for small medical cyclotron

  1. Cyclotron Production of Medical Radioisotopes

    SciTech Connect

    Avila-Rodriguez, M. A.; Zarate-Morales, A.; Flores-Moreno, A.

    2010-08-04

    The cyclotron production of radioisotopes for medical applications is gaining increased significance in diagnostic molecular imaging techniques such as PET and SPECT. In this regard, radioisotope production has never been easier or more convenient until de introduction of compact medical cyclotrons in the last few decades, which allowed the use of short-lived radioisotopes in in vivo nuclear medicine studies on a routine basis. This review outlines some general considerations about the production of radioisotopes using charged particle accelerators.

  2. 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].

  3. 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.

  4. [Evaluation of Radio-activated Compounds Produced in the Walls and Adjacent Areas of a Small Medical Cyclotron].

    PubMed

    Saito, Kyoko; Takahashi, Yasuyuki; Yamaguchi, Ichiro; Kimura, Ken-Ichi; Kanzaki, Takao; Shimada, Hirotaka; Otake, Hidenori; Oriuchi, Noboru; Endo, Keigo

    2009-01-01

    According to the (18)O(p, n) (18)F reaction, fast neutrons produced in the target will cause residual radioactivity in a cyclotron itself and in the concrete walls mainly after thermalization of neutrons.As exploratory work prior to decommissioning of a medical cyclotron facility, surface and core samples of the facility's concrete walls were collected after confirming the external radiation was at a low level based on hollow ionization chamber-type survey meter and glass dosimeter measurements. The residual radioactivity in these samples was measured by gamma-spectrometry. Residual radioactivity was detected in all of the components of the cyclotron. In the concrete, eight residual radioactive nuclides were identified. However, radioactivity concentrations of these radionuclides were less than that of (40)K which may exist generally in a natural environment. A clearance level for radioactive solid waste has not been defined nor implemented at present in Japan, and reliable evaluation will be required to minimize radioactive waste at the time of decommissioning. The present results provide basic data for establishment of regulatory guidelines for decommissioning of medical cyclotrons. PMID:21979783

  5. Direct Production of 99mTc via 100Mo(p,2n) on Small Medical Cyclotrons

    NASA Astrophysics Data System (ADS)

    Schaffer, P.; Bénard, F.; Bernstein, A.; Buckley, K.; Celler, A.; Cockburn, N.; Corsaut, J.; Dodd, M.; Economou, C.; Eriksson, T.; Frontera, M.; Hanemaayer, V.; Hook, B.; Klug, J.; Kovacs, M.; Prato, F. S.; McDiarmid, S.; Ruth, T. J.; Shanks, C.; Valliant, J. F.; Zeisler, S.; Zetterberg, U.; Zavodszky, P. A.

    From the efforts of a number of Canadian institutions and private industry collaborations, direct production of 99mTc using medical cyclotrons has recently been advanced from a 1970's academic exercise to a commercial, economically viable solution for regional production. Using GE PETtrace 880 machines our team has established preliminary saturated yields of 2.7 GBq/μA, translating to approximately 174 GBq after a 6 hour irradiation. The team is in the process of assessing the accuracy and reliability of this production value with a goal of optimizing yields by up to 50%.

  6. Development of a Medical Cyclotron Production Facility

    NASA Astrophysics Data System (ADS)

    Allen, Danny R.

    2003-08-01

    Development of a Cyclotron manufacturing facility begins with a business plan. Geographics, the size and activity of the medical community, the growth potential of the modality being served, and other business connections are all considered. This business used the customer base established by NuTech, Inc., an independent centralized nuclear pharmacy founded by Danny Allen. With two pharmacies in operation in Tyler and College Station and a customer base of 47 hospitals and clinics the existing delivery system and pharmacist staff is used for the cyclotron facility. We then added cyclotron products to contracts with these customers to guarantee a supply. We partnered with a company in the process of developing PET imaging centers. We then built an independent imaging center attached to the cyclotron facility to allow for the use of short-lived isotopes.

  7. Rotatable superconducting cyclotron adapted for medical use

    DOEpatents

    Blosser, Henry G.; Johnson, David A.; Riedel, Jack; Burleigh, Richard J.

    1985-01-01

    A superconducting cyclotron (10) rotatable on a support structure (11) in an arc of about 180.degree. around a pivot axis (A--A) and particularly adapted for medical use is described. The rotatable support structure (13, 15) is balanced by being counterweighted (14) so as to allow rotation of the cyclotron and a beam (12), such as a subparticle (neutron) or atomic particle beam, from the cyclotron in the arc around a patient. Flexible hose (25) is moveably attached to the support structure for providing a liquified gas which is supercooled to near 0.degree. K. to an inlet means (122) to a chamber (105) around superconducting coils (101, 102). The liquid (34) level in the cyclotron is maintained approximately half full so that rotation of the support structure and cyclotron through the 180.degree. can be accomplished without spilling the liquid from the cyclotron. With the coils vertically oriented, each turn of the winding is approximately half immersed in liquid (34) and half exposed to cold gas and adequate cooling to maintain superconducting temperatures in the section of coil above the liquid level is provided by the combination of cold gas/vapor and by the conductive flow of heat along each turn of the winding from the half above the liquid to the half below.

  8. Nuclear data relevant to the production of medically important {beta}{sup +} emitting radioisotopes {sup 75}Br, {sup 86}Y, {sup 94m}Tc and {sup 124}I at a small cyclotron

    SciTech Connect

    Qaim, S.M.; Roesch, F.; Scholten, B.; Stoecklin, G.; Kovacs, Z.; Tarkanyi, F.

    1994-12-31

    Excitation functions were measured for the formation of medically important positron emitting radioisotopes {sup 75}Br, {sup 86}Y, {sup 94m}Tc and {sup 124}I at a small cyclotron. The reactions investigated up to about 20 MeV included {sup 78}Kr(p,{alpha}){sup 75}Br, {sup 74}Se(d,n){sup 75}Br, {sup 86}Sr(p,n){sup 86}Y, {sup 94}Mo(p,n){sup 94m}Tc and {sup 124}Te(p,n){sup 124}I. In each case the well-known stacked-foil (in case of {sup 78}Kr gas stacked-cylinder) technique was used and the target material was isotopically enriched. From the cross section data the optimum production conditions for various radioisotopes were deduced. Whereas {sup 86}Y, {sup 94m}Tc, and {sup 124}I can be produced at a small cyclotron in quantities and purity sufficient for medical applications, the achievable batch yields of {sup 75}Br at such a cyclotron are limited.

  9. Review of Cyclotrons for the Production of Radioactive Isotopes for Medical and Industrial Applications

    NASA Astrophysics Data System (ADS)

    Schmor, Paul

    2011-02-01

    Radioactive isotopes are used in a wide range of medical, biological, environmental and industrial applications. Cyclotrons are the primary tool for producing the shorter-lived, proton-rich radioisotopes currently used in a variety of medical applications. Although the primary use of the cyclotron-produced short-lived radioisotopes is in PET/CT (positron emission tomography/computed tomography) and SPECT (single photon emission computed tomography) diagnostic medical procedures, cyclotrons are also producing longer-lived isotopes for therapeutic procedures as well as for other industrial and applied science applications. Commercial suppliers of cyclotrons are responding by providing a range of cyclotrons in the energy range of 3-70MeV for the differing needs of the various applications. These cyclotrons generally have multiple beams servicing multiple targets. This review article presents some of the applications of the radioisotopes and provides a comparison of some of the capabilities of the various current cyclotrons. The use of nuclear medicine and the number of cyclotrons supplying the needed isotopes are increasing. It is expected that there will soon be a new generation of small "tabletop" cyclotrons providing patient doses on demand.

  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. Ion source and injection line for high intensity medical cyclotron

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    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.

  12. A small low energy cyclotron for radioisotope measurements

    SciTech Connect

    Bertsche, K.J.

    1989-11-01

    Direct detection of {sup 14}C by accelerator mass spectrometry has proved to be a much more sensitive method for radiocarbon dating than the decay counting method invented earlier by Libby. A small cyclotron (the cyclotrino'') was proposed for direct detection of radiocarbon in 1980. This combined the suppression of background through the use of negative ions, which had been used effectively in tandem accelerators, with the high intrinsic mass resolution of a cyclotron. Development of a small electrostatically-focused cyclotron for use as a mass spectrometer was previously reported but the sensitivity needed for detection of {sup 14}C at natural abundance was not achieved. The major contributions of this work are the integration of a high current external ion source with a small flat-field, electrostatically-focused cyclotron to comprise a system capable of measuring {sup 14}C at natural levels, and the analysis of ion motion in such a cyclotron, including a detailed analysis of phase bunching and its effect on mass resolution. A high current cesium sputter negative ion source generates a beam of carbon ions which is pre-separated with a Wien filter and is transported to the cyclotron via a series of electrostatic lenses. Beam is injected radially into the cyclotron using electrostatic deflectors and an electrostatic mirror. Axial focusing is entirely electrostatic. A microchannel plate detector is used with a phase-grated output. In its present form the system is capable of improving the sensitivity of detecting {sup 14}C in some biomedical experiments by a factor of 10{sup 4}. Modifications are discussed which could bring about an additional factor of 100 in sensitivity, which is important for archaeological and geological applications. Possibilities for measurements of other isotopes, such as {sup 3}H, and {sup 10}Be, and {sup 26}Al, are discussed. 70 refs.

  13. Miniature cyclotron resonance ion source using small permanent magnet

    NASA Technical Reports Server (NTRS)

    Anicich, V. G.; Huntress, W. T., Jr. (Inventor)

    1980-01-01

    An ion source using the cyclotron resonance principle is described. A miniaturized ion source device is used in an air gap of a small permanent magnet with a substantially uniform field in the air gap of about 0.5 inch. The device and permanent magnet are placed in an enclosure which is maintained at a high vacuum (typically 10 to the minus 7th power) into which a sample gas can be introduced. The ion beam end of the device is placed very close to an aperture through which an ion beam can exit into the apparatus for an experiment.

  14. Miniature cyclotron resonance ion source using small permanent magnet

    NASA Astrophysics Data System (ADS)

    Anicich, V. G.; Huntress, W. T., Jr.

    1980-06-01

    An ion source using the cyclotron resonance principle is described. A miniaturized ion source device is used in an air gap of a small permanent magnet with a substantially uniform field in the air gap of about 0.5 inch. The device and permanent magnet are placed in an enclosure which is maintained at a high vacuum (typically 10 to the minus 7th power) into which a sample gas can be introduced. The ion beam end of the device is placed very close to an aperture through which an ion beam can exit into the apparatus for an experiment.

  15. Nationwide survey on the operational status of medical compact cyclotrons in Japan.

    PubMed

    Fujibuchi, Toshioh; Yamaguchi, Ichiro; Watanabe, Hiroshi; Kimura, Ken-ichi; Tanaka, Shinji; Kida, Tetsuo; Nagaoka, Hiroaki

    2009-07-01

    The management of induced radioactivity of the cyclotron itself and structures is an important issue in decommissioning of medical compact cyclotrons. To obtain basic data on the actual operational conditions of cyclotrons, we performed nationwide survey. The actual beam current was about half of the maximum beam current indicated in the official permits for cyclotron operation. The actual operating time was about 10% of the maximum operating time indicated in the official permits. The average daily radioactive-nuclide ((18)F) production was only 10% of the allowed maximum quantity. From these results, it became clear that the induced radioactivity of a cyclotron and its concrete structures based on the maximum beam current and the maximum operating time may be overestimated. These basic data are expected to be useful for a realistic evaluation and helpful in establishing a rational regulation in regard to radioactive waste control for decommissioning of medical cyclotrons. PMID:20821110

  16. A new generation of medical cyclotrons for the 90`s

    SciTech Connect

    Milton, B.F.

    1995-08-01

    Cyclotrons continue to be efficient accelerators for use in radio-isotope production. In recent years, developments in 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 indicates 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. Existing and potential markets for these cyclotrons will be presented. They will also discuss the possibility of systems capable of extracted energies up to 150 MeV and extracted beam currents of up to 2.0 mA.

  17. Target foil rupture scenario and provision for handling different models of medical cyclotrons used in India

    PubMed Central

    Shaiju, V. S.; Sharma, S. D.; Kumar, Rajesh; Sarin, B.

    2009-01-01

    Medical cyclotron is a particle accelerator used in producing short lived radiotracers such as 18F, 11C, 15O, 13N etc. These radiotracers are labeled with suitable pharmaceuticals for use to gather information related to metabolic activity of the cell using Positron Emission Tomography (PET) scan. Target foil rupture is considered one of the major emergency situations during medical cyclotron operations because there is a potential of over exposure to the working personnel. Radiation protection survey of a self-shielded medical cyclotron installation was carried out during normal and emergency conditions. It is found that the induced activity in the target foil increases with its successive usages. As a case study, we have evaluated the emergency handling procedures of GE PETtrace-6 medical cyclotron. Recommendations have also been made to reduce personal exposure while handling the target foil rupture condition such as the use of L-Bench near the target area and participation of experienced personnel. PMID:20098564

  18. Medical Care for Small Communities.

    ERIC Educational Resources Information Center

    Governor's Committee on Community Health Assistance, Raleigh, NC.

    Technological, social, economic, and political changes have increased the rapidity of changes in the pattern of living in small towns and rural areas. As a result, a large percentage of rural Americans who live at or below the poverty level are not provided adequate medical care. After realizing the shortage of physicians in North Carolina and…

  19. Hospital based superconducting cyclotron for neutron therapy: Medical physics perspective

    NASA Astrophysics Data System (ADS)

    Yudelev, M.; Burmeister, J.; Blosser, E.; Maughan, R. L.; Kota, C.

    2001-12-01

    The neutron therapy facility at the Gershenson Radiation Oncology Center, Harper University Hospital in Detroit has been operational since September 1991. The d(48.5)+Be beam is produced in a gantry mounted superconducting cyclotron designed and built at the National Superconducting Cyclotron Laboratory (NSCL). Measurements were performed in order to obtain the physical characteristics of the neutron beam and to collect the data necessary for treatment planning. This included profiles of the dose distribution in a water phantom, relative output factors and the design of various beam modifiers, i.e., wedges and tissue compensators. The beam was calibrated in accordance with international protocol for fast neutron dosimetry. Dosimetry and radiobiology intercomparions with three neutron therapy facilities were performed prior to clinical use. The radiation safety program was established in order to monitor and reduce the exposure levels of the personnel. The activation products were identified and the exposure in the treatment room was mapped. A comprehensive quality assurance (QA) program was developed to sustain safe and reliable operation of the unit at treatment standards comparable to those for conventional photon radiation. The program can be divided into three major parts: maintenance of the cyclotron and related hardware; QA of the neutron beam dosimetry and treatment delivery; safety and radiation protection. In addition the neutron beam is used in various non-clinical applications. Among these are the microdosimetric characterization of the beam, the effects of tissue heterogeneity on dose distribution, the development of boron neutron capture enhanced fast neutron therapy and variety of radiobiology experiments.

  20. Commercial and PET radioisotope manufacturing with a medical cyclotron

    NASA Astrophysics Data System (ADS)

    Boothe, T. E.; McLeod, T. F.; Plitnikas, M.; Kinney, D.; Tavano, E.; Feijoo, Y.; Smith, P.; Szelecsnyi, F.

    1993-06-01

    Mount Sinai has extensive experience in producing radionuclides for commercial sales and for incorporation into radiopharmaceuticals, including PET. Currently, an attempt is being made to supply radiochemicals to radiopharmaceutical manufacturers outside the hospital, to prepare radiopharmaceuticals for in-house use, and to prepare PET radiopharmaceuticals, such as 2-[F-18] FDG, for outside sales. This use for both commercial and PET manufacturing is atypical for a hospital-based cyclotron. To accomplish PET radiopharmaceutical sales, the hospital operates a nuclear pharmacy. A review of operational details for the past several years shows a continuing dependence on commercial sales which is reflected in research and developmental aspects and in staffing. Developmental efforts have centered primarily on radionuclide production, target development, and radiochemical processing optimization.

  1. Low current performance of the Bern medical cyclotron down to the pA range

    NASA Astrophysics Data System (ADS)

    Auger, M.; Braccini, S.; Ereditato, A.; Nesteruk, K. P.; Scampoli, P.

    2015-09-01

    A medical cyclotron accelerating H- ions to 18 MeV is in operation at the Bern University Hospital (Inselspital). It is the commercial IBA 18/18 cyclotron equipped with a specifically conceived 6 m long external beam line ending in a separate bunker. This feature is unique for a hospital-based facility and makes it possible to conduct routine radioisotope production for PET diagnostics in parallel with multidisciplinary research activities, among which are novel particle detectors, radiation biophysics, radioprotection, radiochemistry and radiopharmacy developments. Several of these activities, such as radiobiology experiments for example, require low current beams down to the pA range, while medical cyclotrons are designed for high current operation above 10 μA. In this paper, we present the first results on the low current performance of a PET medical cyclotron obtained by ion source, radio-frequency and main coil tuning. With this method, stable beam currents down to (1.5+/- 0.5 ) pA were obtained and measured with a high-sensitivity Faraday cup located at the end of the beam transport line.

  2. 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.

  3. Medical Waste Management Implications for Small Medical Facilities.

    ERIC Educational Resources Information Center

    Byrns, George; Burke, Thomas

    1992-01-01

    Discusses the implications of the Medical Waste Management Act of 1988 for small medical facilities, public health, and the environment. Reviews health and environmental risks associated with medical waste, current regulatory approaches, and classifications. Concludes that the health risk of medical wastes has been overestimated; makes

  4. Medical Waste Management Implications for Small Medical Facilities.

    ERIC Educational Resources Information Center

    Byrns, George; Burke, Thomas

    1992-01-01

    Discusses the implications of the Medical Waste Management Act of 1988 for small medical facilities, public health, and the environment. Reviews health and environmental risks associated with medical waste, current regulatory approaches, and classifications. Concludes that the health risk of medical wastes has been overestimated; makes…

  5. Evaluation Study for the Production of the Medical Isotope ^90Y, using a Cyclotron

    NASA Astrophysics Data System (ADS)

    Necsoiu, D.; Morgan, I. L.; Hupf, Homer; Armbruster, J.; Boyce, D.; El Bouanani, M.; McDaniel, F. D.

    2000-10-01

    The use of radioisotopes in therapy, medical imaging and laboratory tests is well-established worldwide. ^90Y is a very good therapeutic candidate for radioimmunotherapy applications. Traditionally, medical radioisotopes are produced using either nuclear reactors or proton accelerators. In this study, the medical isotope ^90Y has been produced using ^90Zr(n,p)^90Y nuclear reaction. Neutrons for the activation process were produced using ^natRh(p,xn) reaction with a 27 MeV proton beam from a cyclotron. Since ^90Y is a pure beta emitter, the gamma rays from the ^90Zr(n,2n)^89Zr reaction were used to quantify the incident neutron flux on the ^90Zr sample. Experimental results of the neutron production and ^90Y activity are presented.

  6. An analytical approach of thermodynamic behavior in a gas target system on a medical cyclotron.

    PubMed

    Jahangiri, Pouyan; Zacchia, Nicholas A; Buckley, Ken; Bénard, François; Schaffer, Paul; Martinez, D Mark; Hoehr, Cornelia

    2016-01-01

    An analytical model has been developed to study the thermo-mechanical behavior of gas targets used to produce medical isotopes, assuming that the system reaches steady-state. It is based on an integral analysis of the mass and energy balance of the gas-target system, the ideal gas law, and the deformation of the foil. The heat transfer coefficients for different target bodies and gases have been calculated. Excellent agreement is observed between experiments performed at TRIUMF's 13 MeV cyclotron and the model. PMID:26562450

  7. A CYCLOTRON CONCEPT TO SUPPORT ISOTOPE PRODUCTION FOR SCIENCE AND MEDICAL APPLICATIONS

    SciTech Connect

    Egle, Brian; Mirzadeh, Saed; Tatum, B Alan; Varma, Venugopal Koikal; Bradley, Eric Craig; Burgess, Thomas W; Aaron, W Scott; Binder, Jeffrey L; Beene, James R; Saltmarsh, Michael John

    2013-01-01

    In August of 2009, the Nuclear Science Advisory Committee (NSAC) recommended a variable-energy, high-current multi-particle accelerator for the production of medical radioisotopes. The Oak Ridge National Laboratory is developing a technical concept for a 70 MeV dual-extraction multi-particle cyclotron that will meet the needs identified in the NSAC report. The cyclotron, which will be located at the Holifield Radioactive Ion Beam Facility (HRIBF), will operate on a 24/7 basis and will provide approximately 6000 hours per year of quality beam time for both the production R&D and production of medical and industrial radioisotopes. The proposed cyclotron will be capable of accelerating dual beams of 30 to 70 MeV H at up to 750 A, and up to 50 A of 15-35 MeV D , 35 MeV H2, and 70 MeV -particles. In dual-extraction H mode, a total of 750 A of 70 MeV protons will be provided simultaneously to both HRIBF and Isotope Production Facility. The isotope facility will consist of two target stations: a 2 water-cooled station and a 4 water-cooled high-energy-beam research station. The multi-particle capability and high beam power will enable research into new regimes of accelerator-produced radioisotopes, such as 225Ac, 211At, 68Ge, and 7B. The capabilities of the accelerator will enable the measurement of excitation functions, thick target yield measurements, research in high-power-target design, and will support fundamental research in nuclear and radiochemistry.

  8. Radiologic assessment of a self-shield with boron-containing water for a compact medical cyclotron.

    PubMed

    Horitsugi, Genki; Fujibuchi, Toshioh; Yamaguchi, Ichiro; Eto, Akihisa; Iwamoto, Yasuo; Hashimoto, Hiromi; Hamada, Seiki; Obara, Satoshi; Watanabe, Hiroshi; Hatazawa, Jun

    2012-07-01

    The cyclotron at our hospital has a self-shield of boron-containing water. The amount of induced radioactivity in the boron-containing water shield of a compact medical cyclotron has not yet been reported. In this study, we measured the photon and neutron dose rates outside the self-shield during cyclotron operation. We estimated the induced radioactivities of the boron-containing water used for the self-shield and then measured them. We estimated the activation of concrete outside the self-shield in the cyclotron laboratory. The thermal neutron flux during cyclotron operation was estimated to be 4.72 × 10(2) cm(-2) s(-1), and the activation of concrete in a cyclotron laboratory was about three orders of magnitude lower than the clearance level of RS-G-1.7 (IAEA). The activity concentration of the boron-containing water did not exceed the concentration limit for radioactive isotopes in drainage in Japan and the exemption level for Basic Safety Standards. Consequently, the boron-containing water is treatable as non-radioactive waste. Neutrons were effectively shielded by the self-shield during cyclotron operation. PMID:22370731

  9. Evaluating secondary neutron doses of a refined shielded design for a medical cyclotron using the TLD approach

    NASA Astrophysics Data System (ADS)

    Lin, Jye-Bin; Tseng, Hsien-Chun; Liu, Wen-Shan; Lin, Ding-Bang; Hsieh, Teng-San; Chen, Chien-Yi

    2013-11-01

    An increasing number of cyclotrons at medical centers in Taiwan have been installed to generate radiopharmaceutical products. An operating cyclotron generates immense amounts of secondary neutrons from reactions such the 18O(p, n)18F, used in the production of FDG. This intense radiation can be hazardous to public health, particularly to medical personnel. To increase the yield of 18F-FDG from 4200 GBq in 2005 to 48,600 GBq in 2011, Chung Shan Medical University Hospital (CSMUH) has prolonged irradiation time without changing the target or target current to meet requirements regarding the production 18F. The CSMUH has redesigned the CTI Radioisotope Delivery System shield. The lack of data for a possible secondary neutron doses has increased due to newly designed cyclotron rooms. This work aims to evaluate secondary neutron doses at a CTI cyclotron center using a thermoluminescent dosimeter (TLD-600). Two-dimensional neutron doses were mapped and indicated that neutron doses were high as neutrons leaked through self-shielded blocks and through the L-shaped concrete shield in vault rooms. These neutron doses varied markedly among locations close to the H218O target. The Monte Carlo simulation and minimum detectable dose are also discussed and demonstrated the reliability of using the TLD-600 approach. Findings can be adopted by medical centers to identify radioactive hot spots and develop radiation protection.

  10. Use of a small off-line computer in the operation of a versatile heavy ion cyclotron

    SciTech Connect

    Gough, R.A.

    1981-03-01

    In a modern heavy ion cyclotron with variable energy and particle species, it is essential to provide the operations staff with fast and easy access to parameter information. At the Berkeley 88-Ion Cyclotron, which operates under manual control, an interactive computer program has been developed to meet this requirement. The program is written in BASIC on a small off-line computer to perform a variety of calculations for any ion species and energy. The program can provide the operator with cyclotron and beam line settings for any beam, regardless of whether or not the beam has been previously run, by utilizing the broad data base acquired over a decade of heavy ion operation. A number of additional calculations now being performed conveniently and routinely by the operations staff will be discussed. The use of this program has greatly streamlined the operation of the cyclotron because needed information can be obtained quickly and reliably.

  11. Selected Reference Aids for Small Medical Libraries *

    PubMed Central

    Duncan, Howertine Farrell

    1970-01-01

    This annotated list of 178 items is compiled as a guide to the development of the reference collection in a small medical library. Arrangement, following the pattern of the previous revision, is by broad subject groups. Titles are chiefly in English. Textbooks in subject fields have been omitted since these are covered adequately in several comprehensive guides to the literature. PMID:5439904

  12. Reclassification in a small decentralized medical library.

    PubMed

    Tong, J G; Brennen, P W; Byrd, G D

    1977-07-01

    This study describes procedures and indentifies problems in the reclassification of a small medical school library collection that is decentralized into five locations in three different communities. A total of 9,915 monographic titles (14,911 volumes) were reclassified in a nine-month period. The reclassification staff consisted of one professional, two nonprofessionals, and one partime student assistant. PMID:884347

  13. Decommissioning procedures for an 11 MeV self-shielded medical cyclotron after 16 years of working time.

    PubMed

    Calandrino, R; del Vecchio, A; Savi, A; Todde, S; Griffoni, V; Brambilla, S; Parisi, R; Simone, G; Fazio, F

    2006-06-01

    The present article describes the decommissioning of a compact, self-shielded, 11 MeV medical cyclotron. A Monte Carlo simulation of the possible nuclear reactions was performed in order to plan the decommissioning activities. In the course of the cyclotron dismantling, cyclotron components, shields, and floor concrete samples were measured. Residual activities were analyzed with a Ge(Li) detector and compared with simulation data. Doses to staff involved in the decommissioning procedure were monitored by individual TL dosimeters. The simulations identified five radioactive nuclides in shields and floor concrete: 55Fe and 45Ca (beta emitters, total specific activity: 2.29 x 10(4) Bq kg) and 152Eu, 154Eu, 60Co (gamma emitters, total specific activity: 1.62 x 10(3) Bq kg-1). Gamma-ray spectrometry confirmed the presence of gamma emitters, corresponding to a total specific activity of 3.40 x 10(2) Bq kg-1. The presence of the radioisotope 124Sb in the lead contained in the shield structure, corresponding to a simulated specific activity of 9.38 x 10(3) Bq kg-1, was experimentally confirmed. The measured dose from external exposure of the involved staff was <20 muSv, in accordance with the expected range of values between 10 and 20 muSv. The measured dose from intake was negligible. Finally, the decommissioning of the 11 MeV cyclotron does not represent a risk for the involved staff, but due to the presence of long-lived radioisotopes, the cyclotron components are to be treated as low level radioactive waste and stored in an authorized storage area. PMID:16691108

  14. 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!

  15. Radiation safety management of residual long-lived radioactivity distributed in an inner concrete wall of a medical cyclotron room.

    PubMed

    Yamaguchi, Ichiro; Kimura, Ken-ichi; Fujibuchi, Toshioh; Takahashi, Yasuyuki; Saito, Kyoko; Otake, Hidenori

    2011-07-01

    The depth distribution of residual long-lived radioactivity in the inner concrete wall of a medical cyclotron room was measured by assaying concrete cores. Seven long-lived radioactive nuclides ((46)Sc, (60)Co, (65)Zn, (134)Cs, (152)Eu, (22)Na and (54)Mn) were identified by gamma-ray spectrometry of the concrete samples. It was confirmed that the gamma-ray-emitting radionuclides induced by thermal neutrons through the (n, γ) reaction are dominant, and that the activity induced by thermal neutrons is greater at a depth of 10-30 cm, rather than at the surface of the concrete, and decreased exponentially beyond a depth of ~40 cm. Although the specific activity at the surface was greater than the clearance level for radioactive waste indicated in IAEA RS-G-1.7, the mean specific activities in the walls and floor were less than the clearance level. PMID:21498855

  16. Ion cyclotron range of frequencies heating of plasma with small impurity production

    DOEpatents

    Ohkawa, Tihiro

    1987-01-01

    Plasma including plasma ions is magnetically confined by a magnetic field. The plasma has a defined outer surface and is intersected by resonance surfaces of respective common ion cyclotron frequency of a predetermined species of plasma ions moving in the magnetic field. A radio frequency source provides radio frequency power at a radio frequency corresponding to the ion cyclotron frequency of the predetermined species of plasma ions moving in the field at a respective said resonance surface. RF launchers coupled to the radio frequency source radiate radio frequency energy at the resonance frequency onto the respective resonance surface within the plasma from a plurality of locations located outside the plasma at such respective distances from the intersections of the respective resonance surface and the defined outer surface and at such relative phases that the resulting interference pattern provides substantially null net radio frequency energy over regions near and including substantial portions of the intersections relative to the radio frequency energy provided thereby at other portions of the respective resonance surface within the plasma.

  17. Analysis of radionuclide concentration in air released through the stack of a radiopharmaceutical production facility based on a medical cyclotron

    NASA Astrophysics Data System (ADS)

    Giardina, M.; Tomarchio, E.; Greco, D.

    2015-11-01

    Positron emitting radionuclides are increasingly used in medical diagnostics and the number of radiopharmaceutical production facilities have been estimated to be growing worldwide. During the process of production and/or patient administration of radiopharmaceuticals, an amount of these radionuclides might become airborne and escape into the environment. Therefore, the analysis of radionuclide concentration in the air released to the stack is a very important issue to evaluate the dose to the population living around the plant. To this end, sampling and measurement of radionuclide concentration in air released through the stack of a Nuclear Medicine Center (NMC), provided with a cyclotron for radiopharmaceuticals production, must be routinely carried out with an automatic measurement system. In this work is presented the air monitoring system realized at "San Gaetano" NMC at Bagheria (Italy) besides the analysis of the recorded stack relesead air concentration data. Sampling of air was carried out continuously and gamma-ray spectrometric measurement are made on-line and for a short time by using a shielded Marinelli beaker filled with sampled air and a gamma detector. The use of this system allows to have 1440 values of air concentration per day from 2002, year of the start of operation with the cyclotron. Therefore, the concentration values are very many and an analysis software is needed to determine the dose to the population. A comparison with the results of a simulation code based on a Gaussian Plume air dispersion modelling allow us to confirm the no-radiological significance of the stack effluent releases in terms of dose to population and to evaluate possible improvements in the plant devices to reduce the air concentration at stack.

  18. Computerizing a Small Medical Practice Trading Tranquility for Tranquilizers

    PubMed Central

    Adams, Richard C.

    1979-01-01

    The use of micro-computers in the solo or small group medical practice environment is a relatively recent development. This paper describes the development and initial field testing of such a system, first in a solo practice, then evolving to a small group. The hardware is briefly detailed, the evolution of the software package is described, the difficulties of implementation and the future plans for the system are all outlined. As the hardware becomes more economical and universally available, use of microcomputers will certainly become commonplace, even in the small office setting, and it offers exciting possibilities for the future.

  19. Analysis of induced radionuclides in replacement parts and liquid wastes in a medical cyclotron solely used for production of 18F for [18F]FDG.

    PubMed

    Mochizuki, S; Ishigure, N; Ogata, Y; Kobayashi, T

    2013-04-01

    Radioactivities produced in replacement parts and liquid wastes in a medical cyclotron used to produce (18)F for [(18)F]FDG with 10MeV protons were analyzed. Nineteen radionuclides were found in the replacement parts and liquid wastes. Among them, long-lived (56)Co in the Havar foils is critical in terms of radioactive waste management. The estimated dose level of exposure for the operating staff during the replacement of parts was around 310μSv/y, which is smaller than the recommended dose limit for workers. PMID:23419430

  20. An interactional approach to conceptualising small talk in medical interactions

    PubMed Central

    Hudak, Pamela L.; Maynard, Douglas W.

    2013-01-01

    In medical interactions, it may seem straightforward to identify ‘small talk’ as casual or social talk superfluous to the institutional work of dealing with patients’ medical concerns. Such a broad characterisation is, however, extremely difficult to apply to actual talk, and more specificity is necessary to pursue analyses of how small talk is produced and what it achieves for participants in medical interactions. We offer an approach to delineating a subgenre of small talk called topicalised small talk (TST), derived on the basis of conversation analytically-informed analyses of routine consultations involving orthopaedic surgeons and older patients. TST is a line of talk that is referentially independent from their institutional identities as patients or surgeons, oriented instead to an aspect of the personal biography of one (or both), or to some neutral topic available to interactants in any setting (e.g. weather). Importantly, TST is an achievement of both patient and surgeon in that generation and pursuit of topic is mutually accomplished. In an exploratory but systematic analysis, when this approach was applied to a purposive sample of surgeon-patient interactions, TST was much more prevalent in visits with White than African American patients. Accounts for possible ethnic differences in TST are suggested. PMID:21545445

  1. Automated cyclotron tuning using beam phase measurements

    NASA Astrophysics Data System (ADS)

    Timmer, J. H.; Röcken, H.; Stephani, T.; Baumgarten, C.; Geisler, A.

    2006-12-01

    The ACCEL K250 superconducting cyclotron is specifically designed for the use in proton therapy systems. The compact medical 250 MeV proton accelerator fulfils all present and future beam requirements for fast scanning treatment systems and is delivered as a turn key system; no operator is routinely required. During operation of the cyclotron heat dissipation of the RF system induces a small drift in iron temperature. This temperature drift slightly detunes the magnetic field and small corrections must be made. A non-destructive beam phase detector has been developed to measure and quantify the effect of a magnetic field drift. Signal calculations were made and the design of the capacitive pickup probe was optimised to cover the desired beam current range. Measurements showed a very good agreement with the calculated signals and beam phase can be measured with currents down to 3 nA. The measured phase values are used as input for a feedback loop controlling the current in the superconducting coil. The magnetic field of the cyclotron is tuned automatically and online to maintain a fixed beam phase. Extraction efficiency is thereby optimised continuously and activation of the cyclotron is minimised. The energy and position stability of the extracted beam are well within specification.

  2. Cyclotrons and positron emitting radiopharmaceuticals

    SciTech Connect

    Wolf, A.P.; Fowler, J.S.

    1984-01-01

    The state of the art of Positron Emission Tomography (PET) technology as related to cyclotron use and radiopharmaceutical production is reviewed. The paper discusses available small cyclotrons, the positron emitters which can be produced and the yields possible, target design, and radiopharmaceutical development and application. 97 refs., 12 tabs. (ACR)

  3. Behavior of Small-Scale Density Fluctuations in Discharges with Off-Axis Electron-Cyclotron Resonance Heating in the T-10 Tokamak

    SciTech Connect

    Shelukhin, D.A.; Vershkov, V.A.; Razumova, K.A.

    2005-12-15

    In experiments on off-axis electron-cyclotron resonance heating in the T-10 tokamak, a steep gradient of the electron temperature was observed to form for a short time at a relative radius of {rho} {approx_equal} 0.25 after the heating power was switched off. Small-scale fluctuations of the electron density were studied with the help of correlation reflectometry. It was found that, in a narrow region near {rho} {approx_equal} 0.25, the amplitude of the density fluctuations was two times lower than that in the ohmic heating phase. Quasi-coherent fluctuations were suppressed over a period of time during which the steep temperature gradient existed. Measurements of the poloidal rotation velocity of turbulent fluctuations show that there is no velocity shear after the heating is switched off. An analysis of the linear growth rates of instabilities shows that the ion-temperature-gradient mode is unstable at {rho} {approx_equal} 0.25 throughout the entire discharge phase. The effect observed can be explained by an increase in the distance between the rational surfaces near the radius at which the safety factor is q = 1 due to the temporary flattening of the q profile after the off-axis electron-cyclotron resonance heating is switched off.

  4. 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.

  5. Microcomputer Systems in Solo and Small Group Medical Practices

    PubMed Central

    Bremer, Roger E.

    1978-01-01

    Technological developments of microprocessors and microcomputers will facilitate transferring the advantages of larger computer installations to solo and small group medical practices. A series of powerful forces will create the need for computer assistance, helping to overcome earlier restraints. Surveys show the physician is anxious for the help, and manufacturers have the needed advanced components under development. A typical advanced system for physical examination and clerical transactions (ASPECT) has been synthesized from the identified components at attractive economies of scale. More orderly and faster patient processing, lower costs for in-office laboratory tests, high quality, comparative diagnostic protocols, processing more patients at lower unit costs, automated administrative procedures and interface with emerging data banks are a few of the many potential benefits to the patient, the practitioner and society. Effective demonstration programs, triggering modified manufacturing and marketing patterns, are pragmatic priorities before the arsenal of these benefits can be effectively arrayed against today's greatest health care adversary - “the inflation crunch.”

  6. A low background-rate detector for ions in the 5 to 50 keV energy range to be used for radioisotope dating with a small cyclotron

    SciTech Connect

    Friedman, P.G.

    1986-11-25

    Accelerator mass spectrometry in tandem Van de Graaff accelerators has proven successful for radioisotope dating small samples. We are developing a 20 cm diameter 30 to 40 keV cyclotron dedicated to high-sensitivity radioisotope dating, initially for /sup 14/C. At this energy, range and dE/dx methods of particle identification are impossible. Thus arises the difficult problem of reliably detecting 30 to 40 keV /sup 14/C at 10/sup -2/ counts/sec in the high background environment of the cyclotron, where lower energy ions, electrons, and photons bombard the detector at much higher rates. We have developed and tested an inexpensive, generally useful ion detector that allows dark-count rates below 10/sup -4/ counts/sec and excellent background suppression. With the cyclotron tuned near the /sup 13/CH background peak, to the frequency for /sup 14/C, the detector suppresses the background to 6 x 10/sup -4/ counts/sec. For each /sup 14/C ion the detectors grazing-incidence Al/sub 2/O/sub 3/ conversion dynode emits about 20 secondary electrons, which are independently multiplied in separate pores of a microchannel plate. The output signal is proportional to the number of secondary electrons, allowing pulse-height discrimination of background. We have successfully tested the detector with positive /sup 12/C, /sup 23/Na, /sup 39/K, /sup 41/K, /sup 85/Rb, /sup 87/Rb, and /sup 133/Cs at 5 to 40 keV, and with 36 keV negative /sup 12/C and /sup 13/CH. It should detect ions and neutrals of all species, at energies above 5 keV, with good efficiency and excellent background discrimination. Counting efficiency and background discrimination improve with higher ion energy. The detector can be operated at least up to 2 x 10/sup -7/ Torr and be repeatedly exposed to air. The maximum rate is 10/sup 6.4/ ions/sec in pulse counting mode and 10/sup 9.7/ ions/sec in current integrating mode.

  7. Future cyclotron systems: An industrial perspective

    SciTech Connect

    Stevenson, N.R.; Dickie, W.J.

    1995-09-01

    The use of commercial cyclotron systems for the production of radioisotopes continues to grow on a world-wide scale. Improvements in technology have significantly increased the production capabilities of modern cyclotron-based isotope production facilities. In particular, the change to negative ion acceleration and new high power systems have resulted in dramatic improvements in reliability, increases in capacity, and decreases in personnel radiation dose. As more and more older machines are retired, decisions regarding their replacement are made based on several factors including the market`s potential and the cyclotron system`s abilities. Taking the case of the recently upgraded TR30 cyclotron at TRIUMF/Nordion, the authors investigate the requirements industrial/medical users are likely to impose on future commercial cyclotron systems and the impact this will have on cyclotron technology by the end of the century.

  8. 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

  9. JSW's baby cyclotron

    SciTech Connect

    Toda, Y.; Kaneda, Y.; Satoh, Y.; Suzukawa, I.; Yamada, T.

    1983-04-01

    Designed by The Japan Steel Works, Ltd., specially for installation in a hospital's medical department and nuclear research laboratory, '' JSW BABY CYCLOTRON '' has been developed to produce short-lived radioisotopes such as 11C, 13N, 15O and 18F. JSW's Baby Cyclotron has some design features. 1) Fixed energy and four sector azimuthally varying field. 2) Compact figure desired for hospital's nuclear medical department 3) A bitter type magnet yoke shielding activity 4) Simple control and operation 5) Easy maintenance without skilled personnel. Type BC105 (P:10MeV, d:5MeV), BC107 (P:10MeV, d:7MeV), BC168 (P:16MeV, d:8MeV) and BC1710 (P:17MeV, d:10MeV) are available according to required amount of radioisotopes. In our radioisotope production test, yield and purity of 11C, 13N, 15O and 18F are usable to clinical diagnosis.

  10. Cyclotron produced radiopharmaceuticals

    NASA Astrophysics Data System (ADS)

    Kopička, K.; Fišer, M.; Hradilek, P.; Hanč, P.; Lebeda, O.

    2003-01-01

    Some of the cyclotron-produced radionuclides may serve as important materials for the production of radiopharmaceuticals. This lecture deals with basic information relating to various aspects of these compounds. In comparison with radionuclides/compounds used for non-medical purposes, radiopharmaceuticals are subject to a broader scale of regulations, both from the safety and efficacy point of view; besides that, there are both radioactive and medical aspects that must be taken into account for any radiopharmaceutical. According to the regulations and in compliance with general rules of work with radioactivity, radiopharmaceuticals should only be prepared/manufactured under special conditions, using special areas and special equipment and applying special procedures (e.g. sterilisation, disinfection, aseptic work). Also, there are special procedures for cleaning and maintenance. Sometimes the requirements for the product safety clash with those for the safety of the personnel; several examples of solutions pertaining to these cases are given in the lecture. Also, the specific role of cyclotron radiopharmaceuticals is discussed.

  11. 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.

  12. Field mapping system for cyclotron magnet

    NASA Astrophysics Data System (ADS)

    Park, K. H.; Jung, Y. G.; Kim, D. E.; Kang, B. K.; Yoon, M.; Chai, J. S.; Kim, Y. S.

    2005-06-01

    This paper presents a Hall probe mapping system for measuring a cyclotron magnet, which has been fabricated for the 13 MeV cyclotron at the Korea Institute of Radiological and Medical Sciences. Two Hall probes are mounted on a precision mechanical x- y stage and map magnetic field in the Cartesian coordinate system. The mapping system uses the 'flying' mode field mapping method to reduce data-acquisition time. The time required for mapping the whole gap-area of the cyclotron magnet is ˜60 min. The relative measurement error for the averaged magnetic field along beam orbit is less than 0.02%. The cyclotron magnet has been corrected using field measurement data, and the achieved total phase excursion of the cyclotron after correction is less than ±15°, which is within the tolerance of ±20° for the total phase excursion.

  13. Factors Influencing Electronic Clinical Information Exchange in Small Medical Group Practices

    ERIC Educational Resources Information Center

    Kralewski, John E.; Zink, Therese; Boyle, Raymond

    2012-01-01

    Purpose: The purpose of this study was to identify the organizational factors that influence electronic health information exchange (HIE) by medical group practices in rural areas. Methods: A purposive sample of 8 small medical group practices in 3 experimental HIE regions were interviewed to determine the extent of clinical information exchange…

  14. Survey of electronic veterinary medical record adoption and use by independent small animal veterinary medical practices in Massachusetts

    PubMed Central

    Krone, Lauren M.; Brown, Catherine M.; Lindenmayer, Joann M.

    2016-01-01

    Objective To estimate the proportion of independent small animal veterinary medical practices in Massachusetts that use electronic veterinary medical records (EVMRs), determine the purposes for which EVMRs are used, and identify perceived barriers to their use. Design Survey. Sample 100 veterinarians. Procedures 213 of 517 independent small animal veterinary practices operating in Massachusetts were randomly chosen for study recruitment. One veterinarian at each practice was invited by telephone to answer a hardcopy survey regarding practice demographics, medical records type (electronic, paper, or both), purposes of EVMR use, and perceived barriers to adoption. Surveys were mailed to the first 100 veterinarians who agreed to participate. Practices were categorized by record type and size (large [≥ 5 veterinarians], medium [3 to 4 veterinarians], or small [1 to 2 veterinarians]). Results 84 surveys were returned; overall response was 84 of 213 (39.4%). The EVMRs were used alone or together with paper records in 66 of 82 (80.5%) practices. Large and medium-sized practices were significantly more likely to use EVMRs combined with paper records than were small practices. The EVMRs were most commonly used for ensuring billing, automating reminders, providing cost estimates, scheduling, recording medical and surgical information, and tracking patient health. Least common uses were identifying emerging infectious diseases, research, and insurance. Eleven veterinarians in paper record–only practices indicated reluctance to change, anticipated technological problems, time constraints, and cost were barriers to EVMR use. Conclusions and Clinical Relevance Results indicated EVMRs were underutilized as a tool for tracking and improving population health and identifying emerging infectious diseases. Efforts to facilitate adoption of EVMRs for these purposes should be strengthened by the veterinary medical, human health, and public health professions. PMID:25029312

  15. The Use of Small Group Tutorials as an Educational Strategy in Medical Education

    ERIC Educational Resources Information Center

    Ferris, Helena

    2015-01-01

    Small group tutorials are an educational strategy that is growing in popularity in medical education. This is indicative of the movement from a traditional teacher centred approach to more student-centred learning, which is characterised by active participation and autonomous learning (Hedge et al, 2011). However, small group teaching is one of…

  16. H- superconducting cyclotron for PET isotope production

    NASA Astrophysics Data System (ADS)

    Smirnov, V. L.; Vorozhtsov, S. B.; Vincent, J.

    2014-11-01

    The scientific design of a 14-MeV H- compact superconducting cyclotron for producing of the 18F and 13N isotopes has been developed. Main requirements to the facility as a medical accelerator are met in the design. In particular, the main requirement for the cyclotron was the smallest possible size due to the superconducting magnet. The calculations show that the proposed cyclotron allows extracted beam intensity over 500 μA. To increase system reliability and production rates, an external H- ion source is applied. The choice of the cyclotron concept, design of the structure elements, calculation of the electromagnetic fields and beam dynamics from the ion source to the extraction system were performed.

  17. PET - radiopharmaceutical facilities at Washington University Medical School - an overview

    SciTech Connect

    Dence, C.S.; Welch, M.J.

    1994-12-31

    The PET program at Washington University has evolved over more than three decades of research and development in the use of positron-emitting isotopes in medicine and biology. In 1962 the installation of the first hospital cyclotron in the USA was accomplished. This first machine was an Allis Chalmers (AC) cyclotron and it was operated until July, 1990. Simultaneously with this cyclotron the authors also ran a Cyclotron Corporation (TCC) CS-15 cyclotron that was purchased in 1977. Both of these cyclotrons were maintained in-house and operated with a relatively small downtime (approximately 3.5%). After the dismantling of the AC machine in 1990, a Japanese Steel Works 16/8 (JSW-16/8) cyclotron was installed in the vault. Whereas the AC cyclotron could only accelerate deuterons (6.2 MeV), the JSW - 16/8 machine can accelerate both protons and deuterons, so all of the radiopharmaceuticals can be produced on either of the two presently owned accelerators. At the end of May 1993, the medical school installed the first clinical Tandem Cascade Accelerator (TCA) a collaboration with Science Research Laboratories (SRL) of Somerville, MA. Preliminary target testing, design and development are presently under way. In 1973, the University installed the first operational PETT device in the country, and at present there is a large basic science and clinical research program involving more than a hundred staff in nuclear medicine, radiation sciences, neurology, neurosurgery, psychiatry, cardiology, pulmonary medicine, oncology, and surgery.

  18. Medical Students Perceive Better Group Learning Processes when Large Classes Are Made to Seem Small

    PubMed Central

    Hommes, Juliette; Arah, Onyebuchi A.; de Grave, Willem; Schuwirth, Lambert W. T.; Scherpbier, Albert J. J. A.; Bos, Gerard M. J.

    2014-01-01

    Objective Medical schools struggle with large classes, which might interfere with the effectiveness of learning within small groups due to students being unfamiliar to fellow students. The aim of this study was to assess the effects of making a large class seem small on the students' collaborative learning processes. Design A randomised controlled intervention study was undertaken to make a large class seem small, without the need to reduce the number of students enrolling in the medical programme. The class was divided into subsets: two small subsets (n = 50) as the intervention groups; a control group (n = 102) was mixed with the remaining students (the non-randomised group n∼100) to create one large subset. Setting The undergraduate curriculum of the Maastricht Medical School, applying the Problem-Based Learning principles. In this learning context, students learn mainly in tutorial groups, composed randomly from a large class every 6–10 weeks. Intervention The formal group learning activities were organised within the subsets. Students from the intervention groups met frequently within the formal groups, in contrast to the students from the large subset who hardly enrolled with the same students in formal activities. Main Outcome Measures Three outcome measures assessed students' group learning processes over time: learning within formally organised small groups, learning with other students in the informal context and perceptions of the intervention. Results Formal group learning processes were perceived more positive in the intervention groups from the second study year on, with a mean increase of β = 0.48. Informal group learning activities occurred almost exclusively within the subsets as defined by the intervention from the first week involved in the medical curriculum (E-I indexes>−0.69). Interviews tapped mainly positive effects and negligible negative side effects of the intervention. Conclusion Better group learning processes can be achieved in large medical schools by making large classes seem small. PMID:24736272

  19. Comparing Two Cooperative Small Group Formats Used with Physical Therapy and Medical Students

    ERIC Educational Resources Information Center

    D'Eon, Marcel; Proctor, Peggy; Reeder, Bruce

    2007-01-01

    This study compared "Structured Controversy" (a semi-formal debate like small group activity) with a traditional open discussion format for medical and physical therapy students. We found that those students who had participated in Structured Controversy changed their personal opinion on the topic more than those who were in the Open Discussion…

  20. Student Perceptions of Independent versus Facilitated Small Group Learning Approaches to Compressed Medical Anatomy Education

    ERIC Educational Resources Information Center

    Whelan, Alexander; Leddy, John J.; Mindra, Sean; Matthew Hughes, J. D.; El-Bialy, Safaa; Ramnanan, Christopher J.

    2016-01-01

    The purpose of this study was to compare student perceptions regarding two, small group learning approaches to compressed (46.5 prosection-based laboratory hours), integrated anatomy education at the University of Ottawa medical program. In the facilitated active learning (FAL) approach, tutors engage students and are expected to enable and

  1. Selected List of Books and Journals for the Small Medical Library *

    PubMed Central

    Brandon, Alfred N.

    1967-01-01

    This updated list of 388 books and 140 journals is intended as a selection aid for the small library of a hospital, medical society, clinic, or similar organization. Books and journals are arranged by subject, with the books followed by an author index, and the journals by an alphabetical title listing. PMID:6041826

  2. Student Perceptions of Independent versus Facilitated Small Group Learning Approaches to Compressed Medical Anatomy Education

    ERIC Educational Resources Information Center

    Whelan, Alexander; Leddy, John J.; Mindra, Sean; Matthew Hughes, J. D.; El-Bialy, Safaa; Ramnanan, Christopher J.

    2016-01-01

    The purpose of this study was to compare student perceptions regarding two, small group learning approaches to compressed (46.5 prosection-based laboratory hours), integrated anatomy education at the University of Ottawa medical program. In the facilitated active learning (FAL) approach, tutors engage students and are expected to enable and…

  3. Composition and production rate of medical waste from a small producer in Greece.

    PubMed

    Graikos, Anastasios; Voudrias, Evangelos; Papazachariou, Athanasios; Iosifidis, Nikolaos; Kalpakidou, Maria

    2010-01-01

    The objective of this work was to determine the composition and production rate of medical waste from the health care facility of social insurance institute, a small waste producer in Xanthi, Greece. Specifically, produced medical waste from the clinical pathology (medical microbiology) laboratory, the X-ray laboratory and the surgery and injection therapy departments of the health facility was monitored for six working weeks. A total of 240 kg medical solid waste was manually separated and weighed and 330 L of liquid medical waste was measured and classified. The hazardous waste fraction (%w/w) of the medical solid waste was 91.6% for the clinical pathology laboratory, 12.9% for the X-ray laboratory, 24.2% for the surgery departments and 17.6% for the injection therapy department. The infectious waste fraction (%w/w) of the hazardous medical solid waste was 75.6% for the clinical pathology laboratory, 0% for the X-ray laboratory, 100% for the surgery departments and 75.6% for the injection therapy department. The total hazardous medical solid waste production rate was 64+/-15 g/patient/d for the clinical pathology laboratory, 7.2+/-1.6 g/patient/d for the X-ray laboratory, 8.3+/-5.1 g/patient/d for the surgery departments and 24+/-9 g/patient/d for the injection therapy department. Liquid waste was produced by the clinical pathology laboratory (infectious-and-toxic) and the X-ray laboratory (toxic). The production rate for the clinical pathology laboratory was 0.03+/-0.003 L/patient/d and for the X-ray laboratory was 0.06+/-0.006 L/patient/d. Due to the small amount produced, it was suggested that the most suitable management scheme would be to transport the hazardous medical waste, after source-separation, to the Prefectural Hospital of Xanthi to be treated with the hospital waste. Assuming this data is representative of other small medical facilities, medical waste production can be estimated for such facilities distributed around Greece. PMID:20156673

  4. Are Risks From Medical Imaging Still too Small to Be Observed or Nonexistent?

    PubMed Central

    2015-01-01

    Several radiation-related professional societies have concluded that carcinogenic risks associated with doses below 50-100 mSv are either too small to be detected, or are nonexistent. This is especially important in the context of doses from medical imaging. Radiation exposure to the public from medical imaging procedures is rising around the world, primarily due to increased utilization of computed tomography. Professional societies and advisory bodies consistently recommend against multiplying small doses by large populations to predict excess radiation-induced cancers, in large part because of the potential for sensational claims of health impacts which do not adequately take the associated uncertainties into account. Nonetheless, numerous articles have predicted thousands of future cancers as a result of CT scanning, and this has generated considerable concern among patients and parents. In addition, some authors claim that we now have direct epidemiological evidence of carcinogenic risks from medical imaging. This paper critically examines such claims, and concludes that the evidence cited does not provide direct evidence of low-dose carcinogenicity. These claims themselves have adverse public health impacts by frightening the public away from medically justified exams. It is time for the medical and scientific communities to be more assertive in responding to sensational claims of health risks. PMID:26673121

  5. Alfven cyclotron instability and ion cyclotron emission

    SciTech Connect

    Gorelenkov, N.N.; Cheng, C.Z.

    1995-07-01

    Two-dimensional solutions of compressional Alfven eigenmodes (CAE) are studied in the cold plasma approximation. For finite inverse aspect ratio tokamak plasmas the two-dimensional eigenmode envelope is localized at the low magnetic field side with the radial and poloidal localization on the order of a/{radical}m and a/(fourth root of m), respectively, where m is the dominant poloidal mode number. Charged fusion product driven Alfven Cyclotron Instability (ACI) of the compressional Alfven eigenmodes provides the explanation for the ion cyclotron emission (ICE) spectrum observed in tokamak experiments. The ACI is excited by fast charged fusion products via Doppler shifted cyclotron wave-particle resonances. The ion cyclotron and electron Landau dampings and fast particle instability drive are calculated perturbatively for deuterium-deuterium (DD) and deuterium-tritium (DT) plasmas. Near the plasma edge at the low field side the velocity distribution function of charged fusion products is localized in both pitch angle and velocity. The poloidal localization of the eigenmode enhances the ACI growth rates by a factor of {radical}m in comparison with the previous results without poloidal envelope. The thermal ion cyclotron damping determines that only modes with eigenfrequencies at multiples of the edge cyclotron frequency of the background ions can be easily excited and form an ICE spectrum similar to the experimental observations. Theoretical understanding is given for the results of TFTR DD and DT experiments with {upsilon}{sub {alpha}0}/{upsilon}{sub A} < 1 and JET experiments with {upsilon}{sub {alpha}0}/{upsilon}{sub A} > 1.

  6. Selected List of Books and Journals for the Small Medical Library *

    PubMed Central

    Brandon, Alfred N.

    1969-01-01

    This updated list of 398 books and 141 journals is intended as a selection aid for the small library of a hospital, medical society, clinic, or similar organization. Books and journals are arranged by subject, with the books followed by an author index, and the journals by an alphabetical title listing. Items suggested for first purchase by smaller libraries are noted by an asterisk. PMID:4888285

  7. Selected List of Books and Journals for the Small Medical Library *

    PubMed Central

    Brandon, Alfred N.

    1971-01-01

    This updated list of 389 books and 135 journals is intended as a selection aid for the small library of a hospital, medical society, clinic, or similar organization. Books and journals are arranged by subject, with the books followed by an author index, and the journals by an alphabetical title listing. Items suggested for first purchase by smaller libraries are noted by an asterisk. PMID:5582092

  8. Open-Source Medical Devices (OSMD) Design of a Small Animal Radiotherapy System

    NASA Astrophysics Data System (ADS)

    Prajapati, S.; Mackie, T. R.; Jeraj, R.

    2014-03-01

    Open-Source Medical Devices (OSMD) was initiated with the goal of facilitating medical research by developing medical technologies including both hardware and software on an open-source platform. Our first project was to develop an integrated imaging and radiotherapy device for small animals that includes computed tomography (CT), positron emission tomography (PET) and radiation therapy (RT) modalities for which technical specifications were defined in the first OSMD conference held in Madison, Wisconsin, USA in December 2011. This paper specifically focuses on the development of a small animal RT (micro-RT) system by designing a binary micro multileaf collimator (bmMLC) and a small animal treatment planning system (SATPS) to enable intensity modulated RT (IMRT). Both hardware and software projects are currently under development and their current progresses are described. After the development, both bmMLC and TPS will be validated and commissioned for a micro-RT system. Both hardware design and software development will be open-sourced after completion.

  9. Selected list of books and journals for the small medical library.

    PubMed Central

    Brandon, A N; Hill, D R

    1979-01-01

    This revised list of 492 books and 138 journals is intended as a selection guide for small or medium-sized hospital libraries or for the small medical library serving a specified clientele. It can also be used as a core list by small hospital library consortia. Books and journals are categorized by subject, with the books being followed by an author index and the journals by an alphabetical title listing. Items suggested for initial purchase by smaller libraries are indicated by an asterisk. To purchase the entire collection of books and to pay for annual subscriptions to all the journals would require an expenditure of about $22,500. The cost of only the asterisked items, recommended for first purchase, totals approximately $6,100. PMID:380695

  10. Selected list of books and journals for the small medical library.

    PubMed Central

    Brandon, A N

    1977-01-01

    This revised list of 472 books and 138 journals is intended as a selection guide for small or medium-sized hospital libraries or for the small medical library serving a specified clientele. It can also be used as a core list by small hospital library consortia. Books and journals are categorized by subject, with the books being followed by an author index and the journals by an alphabetical title listing. Items suggested for initial purchase by smaller libraries are indicated by an asterisk. To purchase the entire collection of books and to pay for annual subscriptions to all the journals would require an expenditure of about $18,200. The cost of only the asterisked items recommended for first purchase totals approximately $4,500. PMID:321057

  11. Selected list of books and journals for the small medical library.

    PubMed Central

    Brandon, A N; Hill, D R

    1981-01-01

    This revised list of 539 books and 136 journals is intended as a selection guide for small or medium-sized hospital libraries or for small medical libraries in comparable health care facilities. It can also be used as a core list by consortia of small hospital libraries. Books and journals are categorized by subject; the book list is followed by an author index and the list of journals by an alphabetical title listing. Items suggested for initial purchase by smaller libraries, 137 books and 54 journals, are indicated by asterisks. To purchase the entire collection of books and to pay for annual subscriptions to all the journals would require an expenditure of about $30,000. The cost of only the asterisked items, which are recommended for first purchase, totals approximately $8,900. PMID:7225656

  12. The networks from medical knowledge and clinical practice have small-world, scale-free, and hierarchical features

    NASA Astrophysics Data System (ADS)

    Tachimori, Yutaka; Iwanaga, Hiroaki; Tahara, Takashi

    2013-12-01

    Here, we constructed and analyzed a network (henceforth, “medical knowledge network”) derived from a commonly used medical text. We show that this medical knowledge network has small-world, scale-free, and hierarchical features. We then constructed a network from data from a hospital information system that reflected actual clinical practice and found that this network also had small-world, scale-free, and hierarchical features. Moreover, we found that both the diagnosis frequency distribution of the hospital network and the diagnosis degree distribution of the medical knowledge network obeyed a similar power law. These findings suggest that the structure of clinical practice may emerge from the mutual influence of medical knowledge and clinical practice, and that the analysis of a medical knowledge network may facilitate the investigation of the characteristics of medical practice.

  13. 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.

  14. Ernest Orlando Lawrence (1901-1958), Cyclotron and Medicine

    SciTech Connect

    Chu, William T.

    2005-09-01

    On August 8, 2001, Lawrence Berkeley National Laboratory celebrated the centennial of the birth of its founder (and namesake), Ernest Orlando Lawrence. For the occasion, many speeches were given and old speeches were remembered. We recall the words of the late Luis Alvarez, a Nobel Laureate and one of the Lawrence's closest colleagues: ''Lawrence will always be remembered as the inventor of the cyclotron, but more importantly, he should be remembered as the inventor of the modern way of doing science''. J. L. Heilbron and R. W. Seidel, in the introduction of their book, ''Lawrence and His Laboratory'' stated, ''The motives and mechanisms that shaped the growth of the Laboratory helped to force deep changes in the scientific estate and in the wider society. In the entrepreneurship of its founder, Ernest Orlando Lawrence, these motives, mechanisms, and changes came together in a tight focus. He mobilized great and small philanthropists, state and local governments, corporations, and plutocrats, volunteers and virtuosos. The work they supported, from astrophysics and atomic bombs, from radiochemistry to nuclear medicine, shaped the way we observe, control, and manipulate our environment.'' Indeed, all over the civilized world, the ways we do science changed forever after Lawrence built his famed Radiation Laboratory. In this editorial, we epitomize his legacy of changing the way we do medicine, thereby affecting the health and well being of all humanity. This year marks the 75th anniversary of the invention of the cyclotron by Ernest Orlando Lawrence at the University of California at Berkeley. Lawrence conceived the idea of the cyclotron early in 1929 after reading an article by Rolf Wideroe on high-energy accelerators. In the spring of 1930 one of his students, Nels Edlefsen, constructed two crude models of a cyclotron. Later in the fall of the same year, another student, M. Stanley Livingston, constructed a 13-cm diameter model that had all the features of early cyclotrons, accelerating protons to 80,000 volts using less than 1,000 volts on a semi-circular accelerating electrode, now called the ''dee''. Following the discovery by J. D. Cockcroft and E. T. S. Walton of how to produce larger currents at higher voltages, Lawrence constructed the first two-dee 27-Inch (69-cm) Cyclotron, which produced protons and deuterons of 4.8 MeV. The 27-Inch Cyclotron was used extensively in early investigations of nuclear reactions involving neutrons and artificial radioactivity. In 1939, working with William Brobeck, Lawrence constructed the 60-Inch (150-cm) Cyclotron, which accelerated deuterons to 19 MeV. It was housed in the Crocker Laboratory, where scientists first made transmutations of some elements, discovered several transuranic elements, and created hundreds of radioisotopes of known elements. At the Crocker Laboratory the new medical modality called nuclear medicine was born, which used radioisotopes for diagnosis and treatment of human diseases. In 1939 Lawrence was awarded the Nobel Prize in Physics, and later element 103 was named ''Lawrencium'' in his honor.

  15. Selected List of Books and Journals for the Small Medical Library *

    PubMed Central

    Brandon, Alfred N.

    1973-01-01

    This updated list of 410 books and 136 journals is intended as a selection aid for the small library of a hospital, medical society, clinic, or similar organization. Books and journals are arranged by subject, with the books followed by an author index, and the journals by an alphabetical title listing. Items suggested for first purchase by smaller libraries are noted by an asterisk. To purchase the entire collection of books and to pay for the annual subscription costs of all the journals would require an expenditure of about $12,000. To acquire only those items suggested for first purchase, approximately $3,250 would be needed. PMID:4702804

  16. Selected list of books and journals for the small medical library.

    PubMed Central

    Brandon, A N; Hill, D R

    1989-01-01

    In the introduction to this revised list of 607 books and 141 journals, quality assurance programs of health care institutions and patient education are suggested as vehicles for more directly involving the hospital library and its collection in patient care. This list is intended as a selection guide for the small or medium-sized library in a hospital or comparable medical facility, or as a core collection for a consortium of small hospital libraries. Books and journals are categorized by subject; the book list is followed by an author/editor index, and the subject list of journals by an alphabetical title listing. To purchase the entire collection of books and to pay for 1989 subscriptions would require about $63,500. The cost of only the asterisked items totals $24,000. PMID:2655782

  17. Selected list of books and journals for the small medical library.

    PubMed Central

    Brandon, A N; Hill, D R

    1991-01-01

    The current financial status of the health care industry is viewed both from its effect on the hospital library collection and the response of the hospital library to the financial crisis. Predecessors of this list have been intended as selection guides for a small or medium-size library in a hospital or comparable medical facility. As the prices of books and journals continue to soar, the secondary purpose as a core collection for a consortium of small hospital libraries or a network sharing library resources may eventually become its primary use. Books (607) and journals (140) are categorized by subject; the book list is followed by an author/editor index, and the subject list of journals by an alphabetical title listing. To purchase the entire collection of books and to pay for 1991 subscriptions would require about $77,700. The cost of only the asterisked items totals $29,300. PMID:2039906

  18. Selected list of books and journals for the small medical library.

    PubMed Central

    Brandon, A N; Hill, D R

    1985-01-01

    The interrelationship of print and electronic media in the hospital library and the relevance of the "Selected List" in 1985 are discussed in the introduction to this revised list of 583 books and 138 journals. The list is meant to be a selection guide for the small or medium-size library in a hospital or comparable medical facility, or a core collection for a consortium of small hospital libraries. Books and journals are categorized by subject; the book list is followed by an author/editor index and the subject list of journals by an alphabetical title listing. Items suggested for initial purchase by smaller libraries are indicated by asterisks. To purchase the entire collection of books and to pay for 1985 subscriptions to all the journals would require about $45,200. The cost of only the asterisked items totals approximately $16,100. PMID:3888331

  19. Selected list of Books and Journals for the small medical library.

    PubMed Central

    Brandon, A N; Hill, D R

    1983-01-01

    The relationship of the "Selected List" to collection development is explored in the introduction to this revised list of 559 books and 135 journals. The list is intended as a selection guide for the small or medium-sized library in a hospital or comparable medical facility or as a core collection for a consortium of small hospital libraries. Books and journals are categorized by subject; the book list is followed by an author/editor index and the subject list of journals by an alphabetical title listing. Items suggested for initial purchase by smaller libraries (155 books and 54 journals) are indicated by asterisks. To purchase the entire collection of books and to pay for annual subscriptions would require an expenditure of about $38,900. The cost of only the asterisked items totals approximately $13,200. PMID:6190523

  20. Selected list of books and journals for the small medical library.

    PubMed Central

    Brandon, A N; Hill, D R

    1987-01-01

    The impact that the hospital librarian's use of management techniques and comprehension of the highly competitive health care environment can have on collection development and resulting information services in his or her library is reviewed in the introduction to this revised list of 600 books and 139 journals. The list is intended as a selection guide for the small or medium-size library in a hospital or comparable medical facility, or a core collection for a consortium of small hospital libraries. Books and journals are categorized by subject; the book list is followed by an author/editor index and the subject list of journals by an alphabetical title listing. Items suggested for initial purchase by smaller libraries are indicated by asterisks. To purchase the entire collection of books and to pay for 1987 subscriptions to all journals would require about $52,600. The cost of only the asterisked items totals approximately $21,000. PMID:3594025

  1. Selected list of books and journals for the small medical library.

    PubMed Central

    Brandon, A N

    1975-01-01

    This revised list of 446 books and 137 journals is intended as a selection guide for small or medium-sized hospital libraries or for the small medical library serving a specified clientele. Books and journals are categorized by subject, with the books being followed by an author index and the journals by an alphabetical title listing. Items suggested for initial purchase by smaller libraries are indicated by an asterisk. To purchase the entire collection of books and to pay for annual subscriptions to all the journals would require an expenditure for about $14,500. The cost of only the asterisked items recommended for first purchase totals approximately $4,100. PMID:1095095

  2. Effectiveness of Case-Based Learning During Small Groups Sessions at Army Medical College.

    PubMed

    Qamar, Khadija; Rehman, Sabah; Khan, Muhammad Alamgir

    2016-03-01

    Apragmatic and sequential mixed method study was conducted at Army Medical College, from October to December 2014 to determine medical students' perceptions regarding effectiveness of small groups during the CBL(case-based learning) sessions. Tutorial Group Effectiveness Instrument (TGEI) was used after written and informed consent. Free text comments about CBL were invited from the respondents and common ones, and were tabulated. The mean scores were calculated and compared among different subgroups of respondents using appropriate independent sample t-test. Content analysis of qualitative segment was done. Ap-value of less than 0.05 was taken as statistically significant. The analysis of qualitative and quantitative variables was integrated in the final interpretation phase to draw conclusion. The average age of the participants was 19.33 ±0.657 years. The difference in scores was statistically insignificant for cognitive (p = 0.537), motivational (p = 0.868), and demotivational (p = 0.125) effectiveness between males and females. Insignificant difference was also observed for qualification of the overall group productivity among male and female students (p = 0.162), and exposed and non-exposed groups (p = 0.272). The perceptions of overwhelming number of participants were in favour of small group discussion as a component of CBL. PMID:26975961

  3. Activities at iThemba LABS Cyclotron Facilities

    NASA Astrophysics Data System (ADS)

    Bark, R. M.; Cornell, J.; Lawrie, J. J.; Vilakazi, Z. Z.

    iThemba Laboratory for Acceleratory Based Sciences (iThemba LABS) is a multi-disciplinary cyclotron facility. Chief among its activities is the operation of a k=200 sepparate sector cyclotron (SSC) which provides proton beams of energies up to 200 MeV. These beams are used for fundamental nuclear physics research in the intermediate energy region, isotope production and medical physics applications. Details on developments regarding the new flagship project at iThemba LABS are also presented.

  4. Small blob identification in medical images using regional features from optimum scale.

    PubMed

    Zhang, Min; Wu, Teresa; Bennett, Kevin M

    2015-04-01

    Recent advances in medical imaging technology have greatly enhanced imaging-based diagnosis which requires computational effective and accurate algorithms to process the images (e.g., measure the objects) for quantitative assessment. In this research, we are interested in one type of imaging objects: small blobs. Examples of small blob objects are cells in histopathology images, glomeruli in MR images, etc. This problem is particularly challenging because the small blobs often have in homogeneous intensity distribution and an indistinct boundary against the background. Yet, in general, these blobs have similar sizes. Motivated by this finding, we propose a novel detector termed Hessian-based Laplacian of Gaussian (HLoG) using scale space theory as the foundation. Like most imaging detectors, an image is first smoothed via LoG. Hessian analysis is then launched to identify the single optimal scale on which a presegmentation is conducted. The advantage of the Hessian process is that it is capable of delineating the blobs. As a result, regional features can be retrieved. These features enable an unsupervised clustering algorithm for postpruning which should be more robust and sensitive than the traditional threshold-based postpruning commonly used in most imaging detectors. To test the performance of the proposed HLoG, two sets of 2-D grey medical images are studied. HLoG is compared against three state-of-the-art detectors: generalized LoG, Radial-Symmetry and LoG using precision, recall, and F-score metrics.We observe that HLoG statistically outperforms the compared detectors. PMID:25265624

  5. Medical Record Clerk Training Program, Course of Study; Student Manual: For Medical Record Personnel in Small Rural Hospitals in Colorado.

    ERIC Educational Resources Information Center

    Community Health Service (DHEW/PHS), Arlington, VA. Div. of Health Resources.

    The manual provides major topics, objectives, activities and, procedures, references and materials, and assignments for the training program. The topics covered are hospital organization and community role, organization and management of a medical records department, international classification of diseases and operations, medical terminology,…

  6. Continuing Veterinary Medical Education Needs Assessment of Small Animal Practitioners in South Korea.

    PubMed

    Chun, Myung-Sun; Hwang, Cheol-Yong

    2015-01-01

    This first survey of small animal veterinarians in Korea explores demographic patterns, previous learning experiences, and program preferences for continuing veterinary medical education (CVME). Data were analyzed to identify and describe learning needs and preferences. Respondents' average CVME hours (38.4 hours/year) exceeded the mandatory 10 hours per year. Almost all respondents recognized the importance of CVME. Lack of time and travel distance were identified as significant barriers to CVME participation. CVME courses scheduled after 9 p.m. on weekdays with a registration fee of up to $50 US per hour were preferred. Respondents clearly defined the educational quality criteria of preferred CVME programs: delivery in a series of interventions in a small seminar format, with lectures on theory combined with practical skill-building wet labs taught by experienced veterinarians and board-certified specialists. Small animal veterinarians in Korea are enthusiastic life-long learners who are strongly motivated to select CVME learning activities based on self-identified needs. The changing environment of veterinary medicine in Korea demands an evolution of CVME quality criteria, such as clear program goals reflecting veterinarians' educational needs and desirable competencies, and specific measurable learning objectives. Moreover, the current accreditation system, which does not encourage hands-on skill development formats, needs urgent improvement. PMID:26075628

  7. Development of the RF cavity for the SKKUCY-9 compact cyclotron

    NASA Astrophysics Data System (ADS)

    Shin, Seungwook; Lee, Jongchul; LEE, Byeong-No; Ha, Donghyup; Namgoong, Ho; Chai, Jongseo

    2015-09-01

    A 9 MeV compact cyclotron, named SKKUCY-9, for a radiopharmaceutical compound especially fludeoxyglucose (FDG) production for a positron emission tomography (PET) machine was developed at Sungkyunkwan University. H- ions which are produced from a Penning Ionization Gauge(PIG) ion source, travel through a normal conducting radio frequency (RF) cavity which operates at 83.2 MHz for an acceleration and electro-magnet for a beam focusing until the ions acquire energy of about 9 MeV. For installation at a small local hospital, our SKKUCY-9 cyclotron is developed to be compact and light-weight, comparable to conventional medical purpose cyclotrons. For compactness, we adapted a deep valley and large angle hill type for the electro-magnet design. Normally a RF cavity is installed inside of the empty space of the magnet valley region, which is extremely small in our case. We faced problems such as difficulties of installing the RF cavity, low Q-value. Despite of those difficulties, a compact RF cavity and its system including a RF power coupler to feed amplified RF power to the RF cavity and a fine tuner to compensate RF frequency variations was successfully developed and tested.

  8. Patterns of Relating Between Physicians and Medical Assistants in Small Family Medicine Offices

    PubMed Central

    Elder, Nancy C.; Jacobson, C. Jeffrey; Bolon, Shannon K.; Fixler, Joseph; Pallerla, Harini; Busick, Christina; Gerrety, Erica; Kinney, Dee; Regan, Saundra; Pugnale, Michael

    2014-01-01

    PURPOSE The clinician-colleague relationship is a cornerstone of relationship-centered care (RCC); in small family medicine offices, the clinician–medical assistant (MA) relationship is especially important. We sought to better understand the relationship between MA roles and the clinician-MA relationship within the RCC framework. METHODS We conducted an ethnographic study of 5 small family medicine offices (having <5 clinicians) in the Cincinnati Area Research and Improvement Group (CARInG) Network using interviews, surveys, and observations. We interviewed 19 MAs and supervisors and 11 clinicians (9 family physicians and 2 nurse practitioners) and observed 15 MAs in practice. Qualitative analysis used the editing style. RESULTS MAs’ roles in small family medicine offices were determined by MA career motivations and clinician-MA relationships. MA career motivations comprised interest in health care, easy training/workload, and customer service orientation. Clinician-MA relationships were influenced by how MAs and clinicians respond to their perceptions of MA clinical competence (illustrated predominantly by comparing MAs with nurses) and organizational structure. We propose a model, trust and verify, to describe the structure of the clinician-MA relationship. This model is informed by clinicians’ roles in hiring and managing MAs and the social familiarity of MAs and clinicians. Within the RCC framework, these findings can be seen as previously undefined constraints and freedoms in what is known as the Complex Responsive Process of Relating between clinicians and MAs. CONCLUSIONS Improved understanding of clinician-MA relationships will allow a better appreciation of how clinicians and MAs function in family medicine teams. Our findings may assist small offices undergoing practice transformation and guide future research to improve the education, training, and use of MAs in the family medicine setting. PMID:24615311

  9. Cyclotron Research and Applications

    SciTech Connect

    Mach, Rostislav

    2010-01-05

    The twenty years old cyclotron U-120M was upgraded for R and D and Production of Radiopharmaceuticals. R and D on short-lived Radiopharmaceuticals production is done at this accelerator. These Radiopharmaceuticals are eventually delivered to nearby hospitals. Development of new diagnostic radiopharmaceuticals is also pursued at the facility. your paper.

  10. Selected list of books and journals for the small medical library.

    PubMed Central

    Brandon, A N; Hill, D R

    1995-01-01

    The complementary informational access roles of the traditional hospital library book and journal collection and the high-tech Internet are viewed from a 1995 perspective. Predecessors of this list have been intended as selection guides for a small or medium-size library in a hospital or comparable medical facility. As the prices of books and journals continue on an upward spiral, the secondary purpose as a core collection for a consortium of small hospital libraries or a network sharing library resources is fast becoming its primary use. Books (610) and journals (141) are categorized by subject; the book list is followed by an author/editor index and the subject list of journals by an alphabetical title listing. Due to requests from librarians, a "minimal core" book collection consisting of 82 titles has been pulled out from the 200 asterisked initial-purchase books. To purchase the entire collection of books and to pay for 1995 subscriptions would require $93,300. The cost of only the asterisked items totals $39,000. The "minimal core" book collection costs $12,700. PMID:7599581

  11. Selected list of books and journals for the small medical library.

    PubMed Central

    Brandon, A N; Hill, D R

    1997-01-01

    The introduction to this revised list (seventeenth version) of 610 books and 141 journals addresses the origin, three decades ago, of the "Selected List of Books and Journals for the Small Medical Library," and the accomplishments of the late Alfred N. Brandon in helping health sciences librarians, and especially hospital librarians, to envision what collection development and a library collection are all about. This list is intended as a selection guide for the small or medium-size library in a hospital or similar facility. More realistically, it can function as a core collection for a library consortium. Books and journals are categorized by subject; the book list is followed by an author/editor index, and the subject list of journals by an alphabetical title listing. Due to continuing requests from librarians, a "minimal core" book collection consisting of 78 titles has been pulled out from the 200 asterisked (*) initial-purchase books and marked with daggers ([symbol: see text]). To purchase the entire collection of books and to pay for 1997 journal subscriptions would require $101,700. The cost of only the asterisked items, books and journals, totals $43,100. The "minimal core" book collection costs $12,600. PMID:9160148

  12. Student perceptions of independent versus facilitated small group learning approaches to compressed medical anatomy education.

    PubMed

    Whelan, Alexander; Leddy, John J; Mindra, Sean; Matthew Hughes, J D; El-Bialy, Safaa; Ramnanan, Christopher J

    2016-01-01

    The purpose of this study was to compare student perceptions regarding two, small group learning approaches to compressed (46.5 prosection-based laboratory hours), integrated anatomy education at the University of Ottawa medical program. In the facilitated active learning (FAL) approach, tutors engage students and are expected to enable and balance both active learning and progression through laboratory objectives. In contrast, the emphasized independent learning (EIL) approach stresses elements from the "flipped classroom" educational model: prelaboratory preparation, independent laboratory learning, and limited tutor involvement. Quantitative (Likert-style questions) and qualitative data (independent thematic analysis of open-ended commentary) from a survey of students who had completed the preclerkship curriculum identified strengths from the EIL (promoting student collaboration and communication) and FAL (successful progression through objectives) approaches. However, EIL led to student frustration related to a lack of direction and impaired completion of objectives, whereas active learning opportunities in FAL were highly variable and dependent on tutor teaching style. A "hidden curriculum" was also identified, where students (particularly EIL and clerkship students) commonly compared their compressed anatomy education or their anatomy learning environment with other approaches. Finally, while both groups highly regarded the efficiency of prosection-based learning and expressed value for cadaveric-based learning, student commentary noted that the lack of grade value dedicated to anatomy assessment limited student accountability. This study revealed critical insights into small group learning in compressed anatomy education, including the need to balance student active learning opportunities with appropriate direction and feedback (including assessment). PMID:26040541

  13. Small-scale medical waste incinerators--experiences and trials in South Africa.

    PubMed

    Rogers, David E C; Brent, Alan C

    2006-01-01

    Formal waste management services are not accessible for the majority of primary healthcare clinics on the African continent, and affordable and practicable technology solutions are required in the developing country context. In response, a protocol was established for the first quantitative and qualitative evaluation of relatively low cost small-scale incinerators for use at rural primary healthcare clinics. The protocol comprised the first phase of four, which defined the comprehensive trials of three incineration units. The trials showed that all of the units could be used to render medical waste non-infectious, and to destroy syringes or render needles unsuitable for reuse. Emission loads from the incinerators are higher than large-scale commercial incinerators, but a panel of experts considered the incinerators to be more acceptable compared to the other waste treatment and disposal options available in under-serviced rural areas. However, the incinerators must be used within a safe waste management programme that provides the necessary resources in the form of collection containers, maintenance support, acceptable energy sources, and understandable operational instructions for the incinerators, whilst minimising the exposure risks to emissions through the correct placement of the units in relation to the clinic and the surrounding communities. On-going training and awareness building are essential in order to ensure that the incinerators are correctly used as a sustainable waste treatment option. PMID:16364626

  14. Selected list of books and journals for the small medical library.

    PubMed Central

    Brandon, A N; Hill, D R

    1993-01-01

    The potential for the hospital library as an accepted patient-focused module is viewed in terms of both the present and the future--or no future--in the introduction to this revised recommended list of 606 books and 143 journals. Predecessors of this list have been intended as selection guides for a small or medium-size library in a hospital or comparable medical facility. Due to rapidly rising prices, the secondary purpose--a basic collection for a consortium of hospital libraries or a network sharing library resources--may eventually become its primary use. Books and journals are categorized by subject; the book list is followed by an author/editor index, and the subject list of journals by an alphabetical title listing. For the first time, a "minimal core collection" consisting of 85 books has been broken out from the 200 asterisked initial purchase books. To purchase the entire collection of books and to pay for the 1993 subscriptions would require about $87,000; the cost of only the asterisked books and journals totals $34,800. The "minimal core list" of books costs $11,600. PMID:8472001

  15. Hypofractionated radiotherapy for medically inoperable stage I non‐small cell lung cancer

    PubMed Central

    Jiang, Wei; Wang, Jian‐Yang; Wang, Jing‐Bo; Liang, Jun; Hui, Zhou‐Guang; Wang, Xiao‐Zhen; Zhou, Zong‐Mei

    2015-01-01

    Abstract Background To investigate the clinical outcomes and toxicity of hypofractionated radiotherapy for medically inoperable stage I non‐small cell lung cancer (NSCLC). Methods Patients treated with radiotherapy at a dose of 4–6 Gy per fraction using fixed‐field intensity modulated radiotherapy (IMRT) or volumetric‐modulated arc therapy (VMAT) at our hospital from June 2005 to December 2013 were analyzed. The total prescription doses ranged from 50–78 Gy with 4–6 Gy per fraction. The median follow‐up period was 24 months. Results A total of 65 patients with stage I NSCLC were analyzed, including 43 primary NSCLC patients and 22 patients with recurrent or second primary NSCLC. An objective response (complete or partial response) was achieved at six months in 84.6% of patients. The three‐year local control rate was 90.8%. Kaplan–Meier estimates of local failure‐free, progression‐free, overall, and cancer‐specific survival rates at three years were 90.3%, 64.3%, 68.9%, and 88.8%, respectively. The rate of symptomatic radiation pneumonitis was 16.9%, and no grade 4–5 toxicity was observed. Conclusion Favorable local control and outcome was achieved with hypofractionated radiotherapy in patients with inoperable stage I NSCLC with acceptable toxicity. The most common schedule of 6 Gy × 12 fractions may be a promising regimen, and a prospective study is in process. PMID:27148414

  16. Brandon/Hill selected list of print books and journals for the small medical library*

    PubMed Central

    Hill, Dorothy R.; Stickell, Henry N.

    2001-01-01

    After thirty-six years of biennial updates, the authors take great pride in being able to publish the nineteenth version (2001) of the “Brandon/Hill Selected List of Print Books and Journals for the Small Medical Library.” This list of 630 books and 143 journals is intended as a selection guide for health sciences libraries or similar facilities. It can also function as a core collection for a library consortium. Books and journals are categorized by subject; the book list is followed by an author/editor index, and the subject list of journals, by an alphabetical title listing. Due to continuing requests from librarians, a “minimal core list” consisting of 81 titles has been pulled out from the 217 asterisked (*) initial-purchase books and marked with daggers (†*) before the asterisks. To purchase the entire collection of 630 books and to pay for 143 2001 journal subscriptions would require $124,000. The cost of only the asterisked items, books and journals, totals $55,000. The “minimal core list” book collection costs approximately $14,300. PMID:11337945

  17. Teaching medical ethics: problem-based learning or small group discussion?

    PubMed Central

    Heidari, Akram; Adeli, Seyyed-Hassan; Taziki, Sadegh-Ali; Akbari, Valliollahe; Ghadir, Mohammad-Reza; Moosavi-Movahhed, Seyyed-Majid; Ahangari, Roghayyeh; Sadeghi-Moghaddam, Parvaneh; Mirzaee, Mohammad-Rahim; Damanpak-Moghaddam, Vahid

    2013-01-01

    Lecture is the most common teaching method used in ethics education, while problem-based learning (PBL) and small group discussion (SGD) have been introduced as more useful methods. This study compared these methods in teaching medical ethics. Twenty students (12 female and 8 male) were randomly assigned into two groups. The PBL method was used in one group, and the other group was taught using the SGD method. Twenty-five open-ended questions were used for assessment and at the end of the course, a course evaluation sheet was used to obtain the students’ views about the advantages and disadvantages of each teaching method, their level of satisfaction with the course, their interest in attending the sessions, and their opinions regarding the effect of teaching ethics on students’ behaviors. The mean score in the PBL group (16.04 ± 1.84) was higher than the SGD group (15.48 ± 2.01). The satisfaction rates in the two groups were 3.00 ± 0.47 and 2.78 ± 0.83 respectively. These differences were not statistically significant. Since the mean score and satisfaction rate in the PBL group were higher than the SGD group, the PBL method is recommended for ethics education whenever possible. PMID:23908762

  18. Software engineering risk factors in the implementation of a small electronic medical record system: the problem of scalability.

    PubMed Central

    Chiang, Michael F.; Starren, Justin B.

    2002-01-01

    The successful implementation of clinical information systems is difficult. In examining the reasons and potential solutions for this problem, the medical informatics community may benefit from the lessons of a rich body of software engineering and management literature about the failure of software projects. Based on previous studies, we present a conceptual framework for understanding the risk factors associated with large-scale projects. However, the vast majority of existing literature is based on large, enterprise-wide systems, and it unclear whether those results may be scaled down and applied to smaller projects such as departmental medical information systems. To examine this issue, we discuss the case study of a delayed electronic medical record implementation project in a small specialty practice at Columbia-Presbyterian Medical Center. While the factors contributing to the delay of this small project share some attributes with those found in larger organizations, there are important differences. The significance of these differences for groups implementing small medical information systems is discussed. PMID:12463804

  19. Intensity limitations in compact H{sup minus} cyclotrons

    SciTech Connect

    Baartman, R.A.

    1995-12-31

    At TRIUMF, we have demonstrated 2.5 mA in a compact H{sup -} cyclotron. It is worthwhile to explore possibility of going to even higher intensity. In small cyclotrons, vertical focusing vanishes at the center. The space charge tune shift further reduces vertical focusing, thus determining an upper limit on instantaneous current. Limit on average current is of course also dependent upon phase acceptance, but this can be made quite large in an H{sup -} cyclotron. Longitudinal space charge on the first turn can reduce the phase acceptance as well. For finite ion source brightness, another limit comes from bunching efficiency in presence of space charge forces. We present methods of calculating and optimizing these limits. In particular, we show that it is possible to achieve 10mA in a 50 MeV compact H{sup -} cyclotron.

  20. A small portable proton exchange membrane fuel cell and hydrogen generator for medical applications.

    PubMed

    Adlhart, O J; Rohonyi, P; Modroukas, D; Driller, J

    1997-01-01

    Small, lightweight power sources for total artificial hearts (TAH), left ventricular assist devices (LVAD), and other medical products are under development. The new power source will provide 2 to 3 times the capacity of conventional batteries. The implications of this new power source are profound. For example, for the Heartmate LVAD, 5 to 8 hours of operation are obtained with 3 lb of lead acid batteries (Personal Communication Mr. Craig Sherman, Thermo Cardiosystems, Inc TCI 11/29/96). With the same weight, as much as 14 hours of operation appear achievable with the proton exchange membrane (PEM) fuel cell power source. Energy densities near 135 watt-hour/L are achievable. These values significantly exceed those of most conventional and advanced primary and secondary batteries. The improvement is mission dependent and even applies for the short deployment cited above. The comparison to batteries becomes even more favorable if the mission length is increased. The higher capacity requires only replacement of lightweight hydride cartridges and logistically available water. Therefore, when one spare 50 L hydride cartridge weighing 115 g is added to the reactant supply the energy density of the total system increases to 230 watt-hour/kg. This new power source is comprised of a hydrogen fueled, air-breathing PEM fuel cell and a miniature hydrogen generator (US Patent No 5,514,353). The fuel cell is of novel construction and differs from conventional bipolar PEM fuel cells by the arrangement of cells on a single sheet of ion-exchange membrane. The construction avoids the weight and volume penalty of conventional bipolar stacks. The hydrogen consumed by the fuel cell is generated load-responsively in the miniature hydrogen generator, by reacting calcium hydride with water, forming in the process hydrogen and lime. The generator is cartridge rechargeable and available in capacities providing up to several hundred watt-hours of electric power. PMID:9152494

  1. Central region of SKKUCY-9 compact cyclotron

    NASA Astrophysics Data System (ADS)

    Jung, S. Y.; Kim, H. W.; Ghergherehchi, M.; Park, J. K.; Chai, J. S.; Kim, S. H.

    2014-04-01

    The development of a 9 MeV compact cyclotron for the production of radioisotopes for medical applications has been recently completed. The machine accelerates negative hydrogen ions generated from an internal PIG (Penning Ion Gauge) ion source following spiral orbits. Some of the structures designed for early beam acceleration, including a pair of center poles providing ions a circular direction, the head of the ion source, and the electrodes, are located in the center of the cyclotron. In this paper we discuss and evaluate the design of the central region that pulls the ions from the chimney of the ion source and directs them into the equilibrium orbit. The magnetic field produced by the center poles was analyzed using the magnetic solver in OPERA-3D TOSCA, and the phase error and ion equilibrium orbit, which is dependent on the kinetic energy within the designed field, were calculated using CYCLONE v8.4. The electric field produced in the acceleration gap was designed using an electrostatic solver. Then, the single beam trajectory was calculated by our own Cyclotron Beam Dynamics (CBD) code. The early orbits, vertical oscillation, acceptable RF phase and the energy gain during the early turns was evaluated. Final goal was to design the central region by the iterative optimization process and verify it with 1 MeV beam experiment.

  2. New magnet pole shape for isochronous cyclotrons

    SciTech Connect

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

    1981-01-01

    A new design has been developed for shaping pole tips to produce the radially increasing fields required for isochronous cyclotrons. The conventional solid hill poles are replaced by poles mounted over a small secondary gap which tapers radially from maximum at the magnet edge to zero near the center. Field measurements with a model magnet and calculations with the code TRIM show an increase in field at the edge of the magnet without the usual corresponding large increase in fringing, and a radial field shape more nearly field independent than for conventional hills. The flying hills have several advantages for variable energy multiparticle cyclotrons: (1) a large reduction in the power dissipated by isochronizing trim coils; (2) a more constant shape and magnitude flutter factor, eliminating flutter coils and increasing the operating range; and (3) a sharper fall-off of the fringe field, simplifying beam extraction.

  3. New magnet pole shape for isochronous cyclotrons

    SciTech Connect

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

    1981-06-01

    A new design has been developed for shaping pole tips to produce the radially increasing fields required for isochronous cyclotrons. The conventional solid hillpoles are replaced by poles mounted over a small secondary gap which tapers radially from maximum at the magnet edge to zero near the center. Field measurements with a model magnet and calculations with the code TRIM show an increase in field at the edge of the magnet without the usual corresponding large increase in fringing, and a radial field shape more nearly field independent than for conventional hills. The flying hills have several advantages for variable energy multiparticle cyclotrons: (1) a large reduction in the power dissipated by isochronizing trim coils; (2) a more constant shape and magnitude flutter factor, eliminating flutter coils and increasing the operating range; and (3) a sharper fall-off of the fringe field, simplifying beam extraction. 6 figures.

  4. Ion cyclotron resonance cell

    DOEpatents

    Weller, R.R.

    1995-02-14

    An ion cyclotron resonance cell is disclosed having two adjacent sections separated by a center trapping plate. The first section is defined by the center trapping plate, a first end trapping plate, and excitation and detector electrodes. The second section includes a second end trapping plate spaced apart from the center plate, a mirror, and an analyzer. The analyzer includes a wavelength-selective light detector, such as a detector incorporating an acousto-optical device (AOD) and a photodetector. One or more ion guides, grounded plates with holes for the ion beam, are positioned within the vacuum chamber of the mass spectrometer between the ion source and the cell. After ions are trapped and analyzed by ion cyclotron resonance techniques in the first section, the ions of interest are selected according to their mass and passed into the second section for optical spectroscopic studies. The trapped ions are excited by light from a laser and caused thereby to fluoresce. The fluorescent light emitted by the excited ions is reflected by the mirror and directed onto the detector. The AOD is scanned, and the photodetector output is recorded and analyzed. The ions remain in the second section for an extended period, enabling multiple studies to be carried out on the same ensemble of ions. 5 figs.

  5. Ion cyclotron resonance cell

    DOEpatents

    Weller, Robert R.

    1995-01-01

    An ion cyclotron resonance cell having two adjacent sections separated by a center trapping plate. The first section is defined by the center trapping plate, a first end trapping plate, and excitation and detector electrodes. The second section includes a second end trapping plate spaced apart from the center plate, a mirror, and an analyzer. The analyzer includes a wavelength-selective light detector, such as a detector incorporating an acousto-optical device (AOD) and a photodetector. One or more ion guides, grounded plates with holes for the ion beam, are positioned within the vacuum chamber of the mass spectrometer between the ion source and the cell. After ions are trapped and analyzed by ion cyclotron resonance techniques in the first section, the ions of interest are selected according to their mass and passed into the second section for optical spectroscopic studies. The trapped ions are excited by light from a laser and caused thereby to fluoresce. The fluorescent light emitted by the excited ions is reflected by the mirror and directed onto the detector. The AOD is scanned, and the photodetector output is recorded and analyzed. The ions remain in the second section for an extended period, enabling multiple studies to be carried out on the same ensemble of ions.

  6. RF cavity design for KIRAMS-430 superconducting cyclotron

    NASA Astrophysics Data System (ADS)

    Jung, In Su; Hong, Bong Hwan; Kang, Joonsun; Kim, Hyun Wook; Kim, Chang Hyeuk; Kwon, Key Ho

    2015-03-01

    The Korea Heavy Ion Medical Accelerator (KHIMA) has developed a superconducting cyclotron for the carbon therapy, which is called KIRAMS-430. The cyclotron is designed to accelerate only 12C6+ ions up to the energy of 430 MeV/u. It uses two normal conducting RF cavities. The RF frequency is about 70.76 MHz. The nominal dee voltage is 70 kV at the center and 160 kV at the extraction. The RF cavity was designed with 4 stems by using CST microwave studio (MWS). In this paper, we represent the simulation results and the optimized design of the RF cavity for the KIRAMS-430.

  7. Nonlinear cyclotron harmonic absorption

    SciTech Connect

    Seol, Jae Chun; Hegna, C. C.; Callen, J. D.

    2009-05-15

    Nonlinear oscillations of particle's energy occur when a particle stays in a resonance zone. In this work, we found that collisionless heating of particles occurs when they pass the microwave beam at first, second, and third harmonic resonances. It is found that the net energy gain of particles from the microwaves is inversely proportional to the wave frequency. It is also found that the net energy gain is dependent on the microwave beam width. The energy gain of particles from a single pass through a resonance zone has been formulated analytically. A numerical calculation has been performed and the results are in good agreement with the analytic calculation. Both analytic and numerical calculations show a strong frequency dependence and a beam width dependence of nonlinear cyclotron resonance heating.

  8. Helium cyclotron resonance within the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Mauk, B. H.; Mcilwain, C. E.; Mcpherron, R. L.

    1981-01-01

    A histogram of electromagnetic Alfven/ion cyclotron wave frequencies, sampled within the geostationary environment and normalized by the equatorial proton cyclotron frequency, shows a dramatic gap centered near the helium (He +) cyclotron frequency. Also, strongly cyclotron phase bunched helium ions (20-200 eV) have been observed directly within the vicinity of wave environments. These observations are interpreted as resulting from the absorption of the waves through cyclotron resonance by cool ambient populations of helium ions.

  9. 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.

  10. The Role of International Medical Graduates in America?s Small Rural Critical Access Hospitals

    ERIC Educational Resources Information Center

    Hagopian, Amy; Thompson, Matthew J.; Kaltenbach, Emily; Hart, L. Gary

    2004-01-01

    Critical access hospitals (CAHs) are a federal Medicare category for isolated rural facilities with 15 or fewer acute care beds that receive cost-based reimbursement from Medicare. Purpose: This study examines the role of foreign-born international medical graduates (IMGs) in the staffing of CAHs. Methods: Chief executive officers (CEOs) of CAH…

  11. The Role of International Medical Graduates in America?s Small Rural Critical Access Hospitals

    ERIC Educational Resources Information Center

    Hagopian, Amy; Thompson, Matthew J.; Kaltenbach, Emily; Hart, L. Gary

    2004-01-01

    Critical access hospitals (CAHs) are a federal Medicare category for isolated rural facilities with 15 or fewer acute care beds that receive cost-based reimbursement from Medicare. Purpose: This study examines the role of foreign-born international medical graduates (IMGs) in the staffing of CAHs. Methods: Chief executive officers (CEOs) of CAH

  12. Cyclotron targets and production technologies used for radiopharmaceuticals in NPI

    NASA Astrophysics Data System (ADS)

    Fišer, M.; Kopička, K.; Hradilek, P.; Hanč, P.; Lebeda, O.; Pánek, J.; Vognar, M.

    2003-01-01

    This paper deals with some technical aspects of the development and production of cyclotronmade radiopharmaceuticals (excluding PET). In this field, nuclear chemistry and pharmacy are in a close contact; therefore, requirements of the both should be taken into account. The principles of cyclotron targetry, separation/recovery of materials and synthesis of active substances are given, as well as issues connected with formulation of pharmaceutical forms. As the radiopharmaceuticals should fulfil the requirements on in vivo preparations, there exist a variety of demands pertaining to Good Manufacturing Practice (GMP) concept, which is also briefly discussed. A typical production chain is presented and practical examples of real technologies based on cyclotron-made radionuclides are given as they have been used in Nuclear Physics Institute of CAS (NPI). Special attention is devoted to the technology of enriched cyclotron targets. Frequently used medicinal products employing cyclotron-produced active substances are characterised (Rb/Kr generators, 123I-labelled MIBG, OIH and MAB's). The cyclotron produced radioactive implants for transluminal coronary angioplasty (radioactive stents) are introduced as an example of a medical device developed for therapeutic application.

  13. EC-5 fifth international workshop on electron cyclotron emission and electron cyclotron heating

    SciTech Connect

    Prater, R.; Lohr, J.

    1985-12-31

    This report contains papers on the following topics: electron cyclotron emission measurements; electron cyclotron emission theory; electron cyclotron heating; gyrotron development; and ECH systems and waveguide development. These paper have been indexed separately elsewhere. (LSP).

  14. Petit bourgeois health care? The big small-business of private complementary medical practice.

    PubMed

    Andrews, Gavin J; Phillips, David R

    2005-05-01

    Although small business private complementary medicine (CAM) has grown to be a significant provider of health care in many Western societies, there has been relatively little research on the sector in business terms and on its wider socio-economic position and role. Using a combined questionnaire and interview survey, and the concept of small business petit bourgeoisie as a framework, this paper considers the character of therapists and their businesses in England and Wales. The findings suggest that typical of the core characteristics of both the petit bourgeoisie and therapists are the selling of goods with a considerable market viability, at the same time financial insecurity; the modest size of businesses; small amounts of direct employment generation and business owners undertaking everyday 'hands-on' work themselves. Certain of the therapists' and business characteristics depart from the stereotypical image of a small businesses class, such as the high incidence of part-time self-employment and incomes being supplemented often by unrelated waged employment. However, given the acknowledged diversity of the petit bourgeoisie between societies and over time, the framework is arguably appropriate in this context, and private CAM a latest guise. Indeed, just as the petit bourgeoisie have traditionally found market niches either neglected or rejected by bigger business, small business CAM has provided the forms of health care neglected and sometimes rejected by orthodox medicine. PMID:15955291

  15. Multimegawatt cyclotron autoresonance accelerator

    SciTech Connect

    Hirshfield, J.L.; LaPointe, M.A.; Ganguly, A.K.; Yoder, R.B.; Wang, C.

    1996-05-01

    Means are discussed for generation of high-quality multimegawatt gyrating electron beams using rf gyroresonant acceleration. TE{sub 111}-mode cylindrical cavities in a uniform axial magnetic field have been employed for beam acceleration since 1968; such beams have more recently been employed for generation of radiation at harmonics of the gyration frequency. Use of a TE{sub 11}-mode waveguide for acceleration, rather than a cavity, is discussed. It is shown that the applied magnetic field and group velocity axial tapers allow resonance to be maintained along a waveguide, but that this is impractical in a cavity. In consequence, a waveguide cyclotron autoresonance accelerator (CARA) can operate with near-100{percent} efficiency in power transfer from rf source to beam, while cavity accelerators will, in practice, have efficiency values limited to about 40{percent}. CARA experiments are described in which an injected beam of up to 25 A, 95 kV has had up to 7.2 MW of rf power added, with efficiencies of up to 96{percent}. Such levels of efficiency are higher than observed previously in any fast-wave interaction, and are competitive with efficiency values in industrial linear accelerators. Scaling arguments suggest that good quality gyrating megavolt beams with peak and average powers of 100 MW and 100 kW can be produced using an advanced CARA, with applications in the generation of high-power microwaves and for possible remediation of flue gas pollutants. {copyright} {ital 1996 American Institute of Physics.}

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

    NASA Astrophysics Data System (ADS)

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

  17. Cyclotron and linac production of Ac-225.

    PubMed

    Melville, Graeme; Allen, Barry J

    2009-04-01

    Radium needles that were once implanted into tumours as a cancer treatment are now obsolete and constitute a radioactive waste problem, as their half-life is 1600 years. The reduction of radium by photonuclear transmutation by bombarding Ra-226 with high-energy photons from a medical linear accelerator (linac) has been investigated. A linac dose of 2800 Gy produced about 2.4 MBq (64 microCi) of Ra-225, which decays to Ac-225 and can then be used for 'Targeted Alpha Therapy' (TAT) of cancer. This result, while consistent with theoretical calculations, is far too low to be of practical use unless much larger quantities of radium are irradiated. The increasing application of Ac-225 for cancer therapy indicates the potential need for its increased production and availability. This paper investigates the possibility of producing of Ac-225 in commercial quantities, which could potentially reduce obsolete radioactive material and displace the need for expensive importation of Ac-225 from the USA and Russia in the years ahead. Scaled up production of Ac-225 could theoretically be achieved by the use of a high current cyclotron or linac. Production specifications are determined for a linac in terms of current, pulse length and frequency, as well as an examination of other factors such as radiation issues and radionuclei separation. Yields are compared with those calculated for the Australian National Cyclotron in Sydney. PMID:19135381

  18. Electron cyclotron harmonic wave acceleration

    NASA Technical Reports Server (NTRS)

    Karimabadi, H.; Menyuk, C. R.; Sprangle, P.; Vlahos, L.

    1987-01-01

    A nonlinear analysis of particle acceleration in a finite bandwidth, obliquely propagating electromagnetic cyclotron wave is presented. It has been suggested by Sprangle and Vlahos in 1983 that the narrow bandwidth cyclotron radiation emitted by the unstable electron distribution inside a flaring solar loop can accelerate electrons outside the loop by the interaction of a monochromatic wave propagating along the ambient magnetic field with the ambient electrons. It is shown here that electrons gyrating and streaming along a uniform, static magnetic field can be accelerated by interacting with the fundamental or second harmonic of a monochromatic, obliquely propagating cyclotron wave. It is also shown that the acceleration is virtually unchanged when a wave with finite bandwidth is considered. This acceleration mechanism can explain the observed high-energy electrons in type III bursts.

  19. Use of cyclotrons in medicine

    NASA Astrophysics Data System (ADS)

    Qaim, S. M.

    2004-10-01

    Cyclotrons are versatile ion-accelerating machines which find many applications in medicine. In this short review their use in hadron therapy is briefly discussed. Proton therapy is gaining significance because of its capability to treat deep-lying tumours. A strong area of application of cyclotrons involves the production of short-lived neutron deficient radiotracers for use in emission tomography, especially positron emission tomography. This fast and quantitative in vivo diagnostic technique is being increasingly used in neurology, cardiology and oncology. Besides routine patient care, considerable interdisciplinary work on development of new positron emitters is under way. A short account of those efforts is given. The use of cyclotrons in the production of radionuclides for internal radiotherapy is also briefly described.

  20. Design of Small-sized and Low-cost Front End to Medical Microwave Radiometer

    PubMed Central

    Klemetsen, O.; Birkelund, Y.; Maccarini, P. F.; Stauffer, P.; Jacobsen, S. K.

    2013-01-01

    We have investigated the possibility of building a Dicke radiometer that is inexpensive, small-sized, stable, high sensitivity and consists of readily available microwave components. The selected frequency band is at 3–4 GHz and can be used for breast cancer detection, with sufficient spatial resolution. We have found microwave components that are small (< 5mm × 5 mm) and provide sufficient sensitivity. We have built two different Dicke radiometers: One is of conventional design with Dicke switch at front end to select antenna or noise rererence and the other with a low noise amplifier before the Dicke Switch. We have tested this concept with simulations and built prototypes. The two designs provide a gain of approximately 50 dB, and bandwidth of about 500 MHz. One of the designs has a stability μ > 1 and the other design provide instability μ < 1 for a part of the pass band. The prototypes are tested for sensitivity after calibration in two different known temperature waterbaths. The results show that the design with the low noise amplifier before the Dicke switch has 36% higher sensitivity than the other design with Dicke switch in front. PMID:25324916

  1. Beam intensity modulation at the PSI Philips Cyclotron

    NASA Astrophysics Data System (ADS)

    Schmelzbach, P. A.; Stammbach, Th.

    2001-12-01

    The intensity delivered by the PSI Philips Cyclotron is controlled by means of an electrostatic deflector and collimators located close to the center of the accelerator. This system allows for the precise stabilization and smooth modulation of the beam intensity, the generation of beam pulses of variable length and repetition rate, and the fast interruption of the beam in case of emergency. This technique is particularly well suited for present and future medical applications.

  2. Cyclotrons and radiopharmaceuticals in positron emission tomography

    SciTech Connect

    Not Available

    1988-03-11

    Positron emission tomography (PET) can prober biochemical pathways in vivo and can provide quantitative data; for that purpose, tracers labeled with positron-emitting radioisotopes are essential. This report describes the tracers that are being used or that may have future use, their production by cyclotrons, and other needed resources for PET imaging. Current routine and automated methods for convenient production of labeled compounds, coupled with simple computer-controlled accelerators, can support the creation of clinical PET centers in any large medical institution, obviating the need for in-depth research teams. An alternate approach involves the development of regional centers that provide in-house service and that supply fluorine 18- and carbon 11- labeled compounds to nearby hospitals with PET machines.

  3. Brandon/Hill selected list of books and journals for the small medical library.

    PubMed Central

    Hill, D R

    1999-01-01

    The interrelationship of print and electronic media in the hospital library and its relevance to the "Brandon/Hill Selected List" in 1999 are addressed in the updated list (eighteenth version) of 627 books and 145 journals. This list is intended as a selection guide for the small or medium-size library in a hospital or similar facility. More realistically, it can function as a core collection for a library consortium. Books and journals are categorized by subject; the book list is followed by an author/editor index, and the subject list of journals by an alphabetical title listing. Due to continuing requests from librarians, a "minimal core" book collection consisting of 82 titles has been pulled out from the 214 asterisked (*) initial-purchase books and marked with daggers ([symbol: see text]). To purchase the entire collection of books and to pay for 1999 journal subscriptions would require $114,900. The cost of only the asterisked items, books and journals, totals $49,100. The "minimal core" book collection costs $13,200. PMID:10219475

  4. Electrostatic ion cyclotron velocity shear instability

    SciTech Connect

    Lemons, D.S.; Winske, D.; Gary, S.P. )

    1992-12-01

    An electrostatic ion cyclotron instability driven by sheared velocity flow perpendicular to a uniform magnetic field is investigated in the local approximation. The dispersion equation, which includes all kinetic effects and involves only one important parameter, is cast in the form of Gordeyev integrals and solved numerically. The instability occurs roughly at multiples of the ion cyclotron frequency (but modified by the shear) with the growth rate of the individual harmonics overlapping in wavenumber. At small values of the shear parameter, the instability exists in two branches, one at long wavelength, [kappa][rho][sub i] [approximately] 0.5, and one at short wavelength, [kappa][rho][sub i] > 1.5 ([kappa][rho][sub i] is the wavenumber normalized to the ion gyroradius). At larger values of the shear parameter only the longer wavelength branch persists. The growth rate of the long wavelength mode, maximized over wavenumber and frequency, increases monotonically with the shear parameter. Properties of the instability are compared to those of Ganguli et al. obtained in the nonlocal limit.

  5. Percutaneous radiofrequency ablation for medically inoperable patients with clinical stage I non-small cell lung cancer

    PubMed Central

    Liu, Baodong; Liu, Lei; Hu, Mu; Qian, Kun; Li, Yuanbo

    2015-01-01

    Background A retrospective evaluation of percutaneous radiofrequency ablation (RFA) in medically inoperable patients with clinical stage I non-small cell lung cancer (NSCLC). Methods Between 2008 and 2014, 29 medically inoperable patients with clinical stage I NSCLC underwent percutaneous RFA. We evaluated the feasibility, safety, and effectiveness. Results There were 18 men and 11 women with a median age of 78.0 years (range 56–85), mean 76.0 years. No procedure-related deaths occurred in any of the 33 ablation procedures. The mean follow-up was 25 months. The incidence of local tumor progression was 21.0% at 25 months of median time to progression after the initial RFA. The mean overall survival (OS) was 57 months (95% confidence interval (CI) 44–70 months). The mean cancer-specific survival CSS was 63 months (95% CI 50–75 months). OS was 90.5% ± 6.4% at one year, 76.4% ± 10.7% at two, and 65.5% ± 13.6% at three years. CSS was 95.2% ± 4.6% at one, 86.6% ± 9.3% at two, and 74.2% ± 13.9% at three years in all patients. The survival for stage IA and IB cancers were 87.5% and 92.3% at one, 87.5% and 73.4% at two, and 87.5% and 58.7% at three years, respectively. Survival rates were not significantly different between the two groups (P = 0.596), with mean survival times of 65 (95% CI: 51–79 months) and 55 months (95% CI: 38–71 months), respectively. Conclusion Percutaneous RFA is a safe, feasible, and effective procedure in medically inoperable clinical stage I NSCLC patients. PMID:26273379

  6. Duodenal Aspirates for Small Intestine Bacterial Overgrowth: Yield, PPIs, and Outcomes after Treatment at a Tertiary Academic Medical Center.

    PubMed

    Franco, Diana L; Disbrow, Molly B; Kahn, Allon; Koepke, Laura M; Harris, Lucinda A; Harrison, M Edwyn; Crowell, Michael D; Ramirez, Francisco C

    2015-01-01

    Duodenal aspirates are not commonly collected, but they can be easily used in detection of small intestinal bacterial overgrowth (SIBO). Proton pump inhibitor (PPI) use has been proposed to contribute to the development of SIBO. We aimed to determine the yield of SIBO-positive cultures detected in duodenal aspirates, the relationship between SIBO and PPI use, and the clinical outcomes of patients identified by this method. In a retrospective study, we analyzed electronic medical records from 1263 consecutive patients undergoing upper endoscopy at a tertiary medical center. Aspirates were collected thought out the third and fourth portions of the duodenum, and cultures were considered to be positive for SIBO if they produced more than 100,000 cfu/mL. Culture analysis of duodenal aspirates identified SIBO in one-third of patients. A significantly higher percentage of patients with SIBO use PPIs than patients without SIBO, indicating a possible association. Similar proportions of patients with SIBO improved whether or not they received antibiotic treatment, calling into question the use of this expensive therapy for this disorder. PMID:25694782

  7. Duodenal Aspirates for Small Intestine Bacterial Overgrowth: Yield, PPIs, and Outcomes after Treatment at a Tertiary Academic Medical Center

    PubMed Central

    Franco, Diana L.; Disbrow, Molly B.; Kahn, Allon; Koepke, Laura M.; Harris, Lucinda A.; Ramirez, Francisco C.

    2015-01-01

    Duodenal aspirates are not commonly collected, but they can be easily used in detection of small intestinal bacterial overgrowth (SIBO). Proton pump inhibitor (PPI) use has been proposed to contribute to the development of SIBO. We aimed to determine the yield of SIBO-positive cultures detected in duodenal aspirates, the relationship between SIBO and PPI use, and the clinical outcomes of patients identified by this method. In a retrospective study, we analyzed electronic medical records from 1263 consecutive patients undergoing upper endoscopy at a tertiary medical center. Aspirates were collected thought out the third and fourth portions of the duodenum, and cultures were considered to be positive for SIBO if they produced more than 100,000 cfu/mL. Culture analysis of duodenal aspirates identified SIBO in one-third of patients. A significantly higher percentage of patients with SIBO use PPIs than patients without SIBO, indicating a possible association. Similar proportions of patients with SIBO improved whether or not they received antibiotic treatment, calling into question the use of this expensive therapy for this disorder. PMID:25694782

  8. Excitation of low frequency waves by streaming ions via anomalous cyclotron resonance

    NASA Technical Reports Server (NTRS)

    Wu, C. S.; Dillenburg, D.; Gaffey, J. D., Jr.; Ziebell, L. F.; Goedert, J.; Freund, H. P.

    1978-01-01

    The effect of a small population of streaming ions on low-frequency waves with frequencies below the ion cyclotron frequency is analyzed for three modes of interest: Alfven waves, magnetosonic waves, and ion-cyclotron waves. The instability mechanism is the anomalous cyclotron resonance of the waves with the streaming ions. Conditions for excitation of the three types of waves are derived and expressions for the growth rates are obtained. Excitation of Alfven waves is possible even if the ratio of the densities of the streaming ions to the thermal ions is very small. For magnetosonic waves, excitation can easily occur if waves are propagating parallel or nearly parallel to the ambient magnetic field. As for ion-cyclotron waves, it is found that for the ion-whistler branch the excitation is suppressed over a broader range of wave frequencies than for the fast magnetosonic branch.

  9. The cyclotron laboratory and the RFQ accelerator in Bern

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

  10. The cyclotron laboratory and the RFQ accelerator in Bern

    SciTech Connect

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

    2013-07-18

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

  11. Design study of a superconducting cyclotron for heavy ion therapy

    NASA Astrophysics Data System (ADS)

    Kim, J.; Marti, F.; Blosser, H.

    2001-12-01

    A design study has been made for a superconducting cyclotron to accelerate q/A=0.5 ions to 400 MeV/u for radiotherapy. This work is aimed to show that a superconducting cyclotron employing pillbox yoke and circular coils is a viable and economical option as a dedicated medical accelerator as has been suggested by one of authors, H. Blosser [1]. The magnetic field is to be fixed to avoid the use of complicated trim coils, and the beam energy for patient treatment could be varied with energy degraders. Major design parameters of the magnet are presented along with the results of beam optics study related to the beam extraction.

  12. TRIUMF cyclotron vacuum system refurbishing

    NASA Astrophysics Data System (ADS)

    Sekachev, I.

    2008-03-01

    The cyclotron at TRIUMF was commissioned to full energy in 1974. The volume of the cyclotron vacuum tank is about 100 m3 and it operates at 5×10-8 Torr pressure during beam production. The pumping is mainly based on a Phillips B-20 cryogenerator (Stirling cycle 4-cylinder engine). The cryogenerator supplies helium gas at 16 K and 70 K to cryopanels in the tank. The decreasing reliability of the B-20 and demanding maintenance requirements triggered the decision to completely overhaul or replace the cryogenerator. Replacement with the LINDE-1630 helium refrigerator was found to be the most attractive (technically and economically) option. The details of the proposal with installation of the helium refrigerator and with a continuous flow liquid nitrogen shield cooling system are presented.

  13. Cyclotron resonance of composite fermions.

    PubMed

    Kukushkin, I V; Smet, J H; von Klitzing, K; Wegscheider, W

    2002-01-24

    It is occasionally possible to interpret strongly interacting many-body systems within a single-particle framework by introducing suitable fictitious entities, or 'quasi-particles'. A notable recent example of the successful application of such an approach is for a two-dimensional electron system that is exposed to a strong perpendicular magnetic field. The conduction properties of the system are governed by electron-electron interactions, which cause the fractional quantum Hall effect. Composite fermions, electrons that are dressed with magnetic flux quanta pointing opposite to the applied magnetic field, were identified as apposite quasi-particles that simplify our understanding of the fractional quantum Hall effect. They precess, like electrons, along circular cyclotron orbits, but with a diameter determined by a reduced effective magnetic field. The frequency of their cyclotron motion has hitherto remained enigmatic, as the effective mass is no longer related to the band mass of the original electrons and is entirely generated from electron-electron interactions. Here we demonstrate enhanced absorption of a microwave field in the composite fermion regime, and interpret it as a resonance with the frequency of their circular motion. From this inferred cyclotron resonance, we derive a composite fermion effective mass that varies from 0.7 to 1.2 times that of the electron mass in vacuum as their density is tuned from 0.6 x 10(11) cm(-2) to 1.2 x 10(11) cm(-2). PMID:11807549

  14. Method and apparatus for ion cyclotron spectrometry

    DOEpatents

    Dahl, David A. [Idaho Falls, ID; Scott, Jill R. [Idaho Falls, ID; McJunkin, Timothy R. [Idaho Falls, ID

    2010-08-17

    An ion cyclotron spectrometer may include a vacuum chamber that extends at least along a z-axis and means for producing a magnetic field within the vacuum chamber so that a magnetic field vector is generally parallel to the z-axis. The ion cyclotron spectrometer may also include means for producing a trapping electric field within the vacuum chamber that includes at least a first section that induces a first magnetron effect that increases a cyclotron frequency of an ion and at least a second section that induces a second magnetron effect that decreases the cyclotron frequency of an ion. The cyclotron frequency changes induced by the first and second magnetron effects substantially cancel one another so that an ion traversing the at least first and second sections will experience no net change in cyclotron frequency.

  15. 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.

  16. Adaptive multi-level conditional random fields for detection and segmentation of small enhanced pathology in medical images.

    PubMed

    Karimaghaloo, Zahra; Arnold, Douglas L; Arbel, Tal

    2016-01-01

    Detection and segmentation of large structures in an image or within a region of interest have received great attention in the medical image processing domains. However, the problem of small pathology detection and segmentation still remains an unresolved challenge due to the small size of these pathologies, their low contrast and variable position, shape and texture. In many contexts, early detection of these pathologies is critical in diagnosis and assessing the outcome of treatment. In this paper, we propose a probabilistic Adaptive Multi-level Conditional Random Fields (AMCRF) with the incorporation of higher order cliques for detecting and segmenting such pathologies. In the first level of our graphical model, a voxel-based CRF is used to identify candidate lesions. In the second level, in order to further remove falsely detected regions, a new CRF is developed that incorporates higher order textural features, which are invariant to rotation and local intensity distortions. At this level, higher order textures are considered together with the voxel-wise cliques to refine boundaries and is therefore adaptive. The proposed algorithm is tested in the context of detecting enhancing Multiple Sclerosis (MS) lesions in brain MRI, where the problem is further complicated as many of the enhancing voxels are associated with normal structures (i.e. blood vessels) or noise in the MRI. The algorithm is trained and tested on large multi-center clinical trials from Relapsing-Remitting MS patients. The effect of several different parameter learning and inference techniques is further investigated. When tested on 120 cases, the proposed method reaches a lesion detection rate of 90%, with very few false positive lesion counts on average, ranging from 0.17 for very small (3-5 voxels) to 0 for very large (50+ voxels) regions. The proposed model is further tested on a very large clinical trial containing 2770 scans where a high sensitivity of 91% with an average false positive count of 0.5 is achieved. Incorporation of contextual information at different scales is also explored. Finally, superior performance is shown upon comparing with Support Vector Machine (SVM), Random Forest and variant of an MRF. PMID:26211811

  17. FFAGs and Cyclotrons with Reverse Bends

    NASA Astrophysics Data System (ADS)

    Craddock, Michael; Rao, Yi-Nong

    2009-05-01

    This paper describes tracking studies of radial-sector FFAGs and cyclotrons with reverse bends using the cyclotron equilibrium orbit code CYCLOPS. The results for FFAGs confirm those obtained with lumped-element codes, and suggest that cyclotron codes will prove to be important tools for evaluating the measured fields of FFAG magnets. The results for radial-sector cyclotrons show that the use of negative valley fields would allow vertical focusing to be maintained, and hence allow intense cw beams to be accelerated, to energies as high as 10 GeV.

  18. Use of Modified SOAP Notes and Peer-Led Small-Group Discussion in a Medical Physiology Course: Addressing the Hidden Curriculum

    ERIC Educational Resources Information Center

    Kibble, Jonathan; Hansen, Penelope A.; Nelson, Loren

    2006-01-01

    Peer leading of small-group discussion of cases; use of modified subjective, objective, assessment of physiology (SOAP) notes; and opportunities for self-assessment were introduced into a Medical Physiology course to increase students' awareness and practice of professional behaviors. These changes arose from faculty members' understanding of the…

  19. Evaluation of the latent radiation dose from the activated radionuclides in a cyclotron vault

    NASA Astrophysics Data System (ADS)

    Kim, Hyunduk; Cho, Gyuseong; Kim, Sun A.; Kang, Bo Sun

    2015-02-01

    The production of short-lived radioisotopes for the synthesis of radiopharmaceuticals typically takes advantage of a cyclotron that accelerates a proton beam up to a few tens of MeV. The number of cyclotrons has been continuously increasing since the first operation of the MC-50 for the production of radiopharmaceuticals at the Korea Institute of Radiological & Medical Sciences (KIRAMS) in 1986, and currently 35 cyclotrons are under operation throughout the nation. As the number of operating cyclotrons has increased, concerns about radiation safety for the persons who are working at the facilities and dwelling in the vicinity of the facilities are becoming important issues. Radiation that could emit a time-dependent dose was shown to exist in a cyclotron vault after its shutdown. The calculation of the latent radiation dose rate was performed by using the MCNPX and the FISPACT. The calculated results for the activated long-lived radioisotopes in the concrete wall and the structural components of the cyclotron facility were compared with the measured data that were obtained by using gamma-ray spectroscopy with a HPGe detector.

  20. Engaging with economic evaluation methods: insights from small and medium enterprises in the UK medical devices industry after training workshops

    PubMed Central

    2012-01-01

    Background With increased governmental interest in value assessment of technologies and where medical device manufacturers are finding it increasingly necessary to become more familiar with economic evaluation methods, the study sought to explore the levels of health economics knowledge within small and medium-sized enterprises (SMEs) and to scope strategies they employ to demonstrate the value of their products to purchasers. Methods A short questionnaire was completed by participants attending one of five workshops on product development in the medical device sector that took place in England between 2007 and 2011. From all responses obtained, a large proportion of participants were based in SMEs (N = 43), and these responses were used for the analysis. Statistical analysis using non-parametric tests was performed on questions with approximately interval scales. Qualitative data from participant responses were analysed to reveal emerging themes. Results The questionnaire results revealed that 60% of SME participants (mostly company directors or managers, including product or project managers) rated themselves as having low or no knowledge of health economics prior to the workshops but the rest professed at least medium knowledge. Clinical trials and cost analyses or cost-effectiveness studies were the most highly cited means by which SMEs aim to demonstrate value of products to purchasers. Purchasers were perceived to place most importance on factors of safety, expert opinion, cost-effectiveness and price. However many companies did not utilise formal decision-making tools to prioritise these factors. There was no significant dependence of the use of decision-making tools in general with respect to professed knowledge of health economics methods. SMEs did not state a preference for any particular aspect of potential value when deciding whether to develop a product. A majority of SMEs stated they would use a health economics tool. Research and development teams or marketing and sales departments would most likely use one. Conclusion This study points to the need for further research into the education requirements of SMEs in the area of Health Technology Assessment (HTA) and also for investigation into how SMEs engage with existing HTA processes as required by assessors such as NICE. PMID:22943625

  1. Cyclotron Line Measurements with INTEGRAL

    NASA Technical Reports Server (NTRS)

    Pottschmidt, K.; Kreykenbohm, I.; Caballero, I.; Fritz, S.; Schoenherr, G.; Kretschmar, P.; Wilms, J.; McBride, V. A.; Suchy, S.; Rothschild, R. E.

    2008-01-01

    Due to its broadband energy coverage, INTEGRAL has made important contributions to observing and interpreting cyclotron lines, which are present in the 10-100 keV range of a sample of accreting pulsars. In these systems photons with energies fulfilling the resonance condition inelastically Compton scatter off electrons quantized in the accretion column above the neutron star's magnetic pole(s). This process gives rise to the broad, absorption-like lines or 'cyclotron resonant scattering features' (CRSF). The observed lines allow to directly measure the B-fields of these sources, resulting in values of a few times 1E12G. In this overview I will present recent highlights regarding CRSF observations as well as discuss current ideas and models for the physical conditions in the accretion column. Among the former are the stability of the spectrum of Vela X-1 during giant flares in 2003, the observation of three cyclotron lines during the 2004 outburst of V0332+53, the confirmation of the fundamental line at approximately 45 keV during a 2005 normal outburst of A0535-26, and the simultaneous detection of the two lines in the dipping source 4U 1907+09 (for which also a torque reversal was detected for the first time). Through these and other observations it has become increasingly apparent that two types of observations can potentially be used to constrain the accretion column geometry: the determination of energy ratios for multiple harmonic lines (only two sources with greater than 2 lines are known), was well as the evolution of the fundamental line centroid, which, for different sources, may or may not be correlated with flux. Furthermore, first steps have been taken away from the usual phenomenological description of the lines, towards a physical approach based on self-consistent CRSF modeling. Initial applications are presented.

  2. Orbit dynamics in isochronous cyclotrons

    SciTech Connect

    Welton, T.A.; Nichols, T.

    1981-01-01

    Acceleration of heavy ions in an isochronous cyclotron can lead to a ..nu../sub r/-value near unity for many turns. In ORIC, several departures from 3-fold symmetry unfortunately exist, so that a complex resonant behavior may lead to beam loss. To study these questions, a program has been initiated with the aim of devising and using very efficient algorithms for calculating the motion of ions during acceleration. The eikonal function was chosen as the basis for these studies, with methods and some results here described.

  3. The irradiation facility at the AGOR cyclotron

    NASA Astrophysics Data System (ADS)

    Brandenburg, Sytze; Ostendorf, Reint; Hofstee, Mariet; Kiewiet, Harry; Beijers, Hans

    2007-08-01

    The KVI is conducting radiobiology research using protons up to 190 MeV from the superconducting AGOR cyclotron in collaboration with the University Medical Center Groningen (UMCG) since 1998. Using the same set-up, we have started irradiations for radiation hardness studies of detectors and components for the European Space Agency (ESA) and industrial parties. For these irradiations, we use either mono-energetic protons or a simulated solar flare energy spectrum with fluxes up to 5 × 108 protons cm-2 s-1. Furthermore, tests of radiation effects such as single event upsets, are being performed with intensities down to a few particles/s. Different energies are achieved by degrading the primary beam energy. We are currently developing the capability for heavy ion irradiations in air with beams up to Xe at beam energies between 15 and 45 MeV per nucleon. Performing the irradiations in air simplifies handling and monitoring of the device under test. The high energy allows penetration to the active layer of electronic devices, without modifications to the chip housing. The different ions provide a wide range in LET.

  4. 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.

  5. Linear analysis of ion cyclotron interaction in a multicomponent plasma

    NASA Technical Reports Server (NTRS)

    Gendrin, R.; Ashour-Abdalla, M.; Omura, Y.; Quest, K.

    1984-01-01

    The mechanism by which hot anisotropic protons generate electromagnetic ion cyclotron waves in a plasma containing cold H(+) and He(+) ions is quantitatively studied. Linear growth rates (both temporal and spatial) are computed for different plasma parameters: concentration, temperature,and anisotropy of cold He(+) ions and of hot protons. It is shown that: (1) for parameters typical of the geostationary altitude the maximum growth rates are not drastically changed when a small proportion (about 1 to 20 percent) of cold He(+) ions is present; (2) because of the important cyclotron absorption by thermal He(+) ions in the vicinity of the He(+) gyrofrequency, waves which could resonate with the bulk of the He(+) distribution cannot be generated. Therefore quasi-linear effects, in a homogeneous medium at least, cannot be responsible for the heating of He(+) ions which is often observed in conjunction with ion cyclotron waves. The variation of growth rate versus wave number is also studied for its importance in selecting suitable parameters in numerical simulation experiments.

  6. Electron cyclotron resonance plasma photos

    SciTech Connect

    Racz, R.; Palinkas, J.; Biri, S.

    2010-02-15

    In order to observe and study systematically the plasma of electron cyclotron resonance (ECR) ion sources (ECRIS) we made a high number of high-resolution visible light plasma photos and movies in the ATOMKI ECRIS Laboratory. This required building the ECR ion source into an open ECR plasma device, temporarily. An 8MP digital camera was used to record photos of plasmas made from Ne, Ar, and Kr gases and from their mixtures. We studied and recorded the effect of ion source setting parameters (gas pressure, gas composition, magnetic field, and microwave power) to the shape, color, and structure of the plasma. The analysis of the photo series gave us many qualitative and numerous valuable physical information on the nature of ECR plasmas.

  7. Cyclotron resonance absorption in ionospheric plasma

    NASA Astrophysics Data System (ADS)

    Villalon, Elena

    1991-04-01

    The mode conversion of ordinary polarized electromagnetic waves into electrostatic cyclotron waves in the inhomogeneous ionospheric plasma is investigated. Near resonance the warm plasma dispersion relation is a function of the angle theta between the geomagnetic field and the density gradient and of the wave frequency omega, which lies between the electron cyclotron frequency and its doubling. The differential equations describing the electric field amplitudes near the plasma resonance are studied, including damping at the second gyroharmonic. The energy transmission coefficients and power absorbed by the cyclotron waves are calculated. The vertical penetration of the plasma wave amplitudes is estimated using a WKB analysis of the wave equation.

  8. Design study of an ultra-compact superconducting cyclotron for isotope production

    NASA Astrophysics Data System (ADS)

    Smirnov, V.; Vorozhtsov, S.; Vincent, J.

    2014-11-01

    A 12.5 MeV, 25 μA, proton compact superconducting cyclotron for medical isotope production has been designed and is currently in fabrication. The machine is initially aimed at producing 13N ammonia for Positron Emission Tomography (PET) cardiology applications. With an ultra-compact size and cost-effective price point, this system will offer clinicians unprecedented access to the preferred radiopharmaceutical isotope for cardiac PET imaging. A systems approach that carefully balanced the subsystem requirements coupled to precise beam dynamics calculations was followed. The system is designed to irradiate a liquid target internal to the cyclotron and to minimize the need for radiation shielding. The main parameters of the cyclotron, its design, and principal steps of the development work are presented here.

  9. Radio-frequency system of the KIRAMS-30 cyclotron for RI mass production

    NASA Astrophysics Data System (ADS)

    Jung, In Su; Park, Yeunsoo; Kang, Joonsun; Kang, Gun Uk; An, Dong Hyun; Hahn, Garam; Hong, Bong Hwan; Hur, Min Goo; Cho, Jun Dong; Kim, Moon-Hyun; Kwon, Key Ho

    2012-07-01

    The KHIMA (Korea Heavy Ion Medical Accelerator) had developed the KIRAMS-30 cyclotron in collaboration with the ARTI (Advanced Radiation Technology Institute). This cyclotron is able to accelerate proton for the mass production of radioisotopes. It is designed to use two normal conduct RF cavities. The resonant frequency of the ion is 15.99 MHz because of the magnet design and the beam dynamics. The RF frequency is 63.96 MHz because of the 4 th harmonic number. By using computer simulation codes, we estimated the principle design parameters of the RF system, we simulated the electric field distribution. In this paper, we present the design features, the results of quality assessment tests for the RF system, and important issues taken into consideration when designing such a cyclotron.

  10. Nonlinear evolution of electromagnetic ion cyclotron waves

    SciTech Connect

    Silin, I.; Sydora, R. D.; Mann, I. R.; Sauer, K.; Mace, R. L.

    2011-04-15

    Hybrid Vlasov-Fourier modeling is used to investigate the nonlinear evolution of electromagnetic ion cyclotron (EMIC) waves driven by proton temperature anisotropy in plasmas with a population of He{sup +} ions and a cold proton background. In the pure proton-electron plasma, most of the free energy is converted into high-amplitude waves and currents. In the nonlinear stage, within a few hundred proton gyroperiods after the saturation, the wave spectrum shifts toward lower wave numbers and frequencies, from {omega}{approx}0.6{Omega}{sub p} to below {omega}{approx}0.25{Omega}{sub p}. In the presence of even a small population of He{sup +} ions almost all of the free energy is used in He{sup +} heating. The wave activity in the saturated state moves from the linearly unstable upper branch to the linearly stable lower one. In the presence of a background of cold protons, the waves can propagate in the frequency stop-band. Our results demonstrate that linear stability theory cannot be used to estimate the characteristics of the expected saturated wave spectra in the terrestrial magnetosphere. Significantly, our nonlinear simulations produce wave spectra which are in close agreement with the EMIC waves observed in situ by satellites as well as by ground-based magnetometers positioned at the ends of the magnetic field lines.

  11. Compact millimeter wave cyclotron resonance maser

    NASA Astrophysics Data System (ADS)

    Luhmann, N. C., Jr.; McDermott, D. B.; Peebles, W. A.

    1982-08-01

    The building of the gyrotron chamber and associated apparatus is described. The system is operational and measurements have begun. Using only 50 kW of the 200 kW available from the X-band magnetron, the rf accelerator produced 100 mA, 100-250 keV beams. Millimeter wave measurements were made. The second gyrotron cavity, which was designed to be excited by approximately 150 keV beams, yielded approximately 100 W at 26-46 GHz, which corresponds to 1% electron to output wave energy conversion efficiency. This cavity was designed to be undercoupled due to start oscillation considerations. The efficiency of electron energy into cavity wave power was on order of 5%. The next cavity tested is critically coupled for higher power operation. Activities include a theoretical description of the large orbit cyclotron harmonic maser which yields encouraging values for device efficiency. Efficiencies as high as 8% are predicted at millimeter wavelength operation with a uniform magnetic field. A small signal theory of the harmonic gyrotron is developed which yields the value of beam current necessary for oscillation.

  12. 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)

  13. Application of compact electron cyclotron resonance ion source

    SciTech Connect

    Muramatsu, M.; Kitagawa, A.; Iwata, Y.; Ogawa, H.; Hojo, S.; Kubo, T.; Kato, Y.; Biri, S.; Fekete, E.; Yoshida, Y.; Drentje, A. G.

    2008-02-15

    The compact electron cyclotron resonance (ECR) ion source with a permanent magnet configuration (Kei2 source) has been developed at National Institute of Radiological Sciences for a new carbon therapy facility. The Kei2 source was designed for production of C{sup 4+} ions; its performance such as beam intensity and stability has already reached the medical requirements. Therefore, the prototype development of the source for medical use is essentially finished. Recently, we have started a few studies on other applications of the source. One is the production of fullerenes in the ECR plasma and modified fullerenes with various atoms for new materials. A second application is the production of multiply charged ions (not only carbon) for ion implantation. In this paper, some basic experiments for these applications are reported.

  14. Cyclotron radiation losses in subcompact tori

    SciTech Connect

    Tetley, W.; Miley, G.

    1980-01-01

    Subcompact tori such as the field reversed mirror (FRM) have a relatively large surface to volume ratio. This has raised concern that in advanced fuel devices cyclotron losses could prevent their viability as reactors. Indeed the cyclotron radiation produced is several times the fusion power. However, due to reabsorption in the FRM plasma, it turns out that less than 7% of the cyclotron radiation produced escapes the plasma. Then when reflection from the first wall is included, net losses are reduced further to < 3 despite a 10% hole fraction in the wall for injector ports. Finally, a global model studies of the FRM show that even if the cyclotron loss rates are four times that predicted, the reactor energy balance remains viable.

  15. 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.

  16. Method and apparatuses for ion cyclotron spectrometry

    DOEpatents

    Dahl, David A.; Scott, Jill R.; McJunkin, Timothy R.

    2012-03-06

    An ion cyclotron spectrometer may include a vacuum chamber that extends at least along a z-axis and means for producing a magnetic field within the vacuum chamber so that a magnetic field vector is generally parallel to the z-axis. The ion cyclotron spectrometer may also include means for producing a trapping electric field within the vacuum chamber. The trapping electric field may comprise a field potential that, when taken in cross-section along the z-axis, includes at least one section that is concave down and at least one section that is concave up so that ions traversing the field potential experience a net magnetron effect on a cyclotron frequency of the ions that is substantially equal to zero. Other apparatuses and a method for performing ion cyclotron spectrometry are also disclosed herein.

  17. Low energy cyclotron for radiocarbon dating

    SciTech Connect

    Welch, J.J.

    1985-01-01

    The author built and tested a low energy cyclotron for radiocarbon dating similar to a conventional mass spectrometer. These tests clearly show that with the addition of a conventional ion source, the low energy cyclotron can perform the extremely high sensitivity /sup 14/C measurements that are now done at accelerator facilities. The author found that no significant background is present when the cyclotron is tuned to accelerate /sup 14/C negative ions and the transmission efficiency is adequate to perform radiocarbon dating on milligram samples of carbon. The internal ion source used did not produce sufficient current to detect /sup 14/C directly at modern concentrations. The author shows how a conventional carbon negative ion source located outside the cyclotron magnet, would produce sufficient beam and provide for quick sample changing to make radiocarbon dating milligram samples with a modest laboratory instrument feasible.

  18. Small Group Learning in Medical Education: A Second Look at the Springer, Stanne, and Donovan Meta-Analysis.

    ERIC Educational Resources Information Center

    Colliver, Jerry A.; Feltovich, Paul J.; Verhulst, Steven J.

    2003-01-01

    Reviews the studies on which a meta-analysis by Springer, Stanne, and Donovan (1999) were based; the meta-analysis had concluded that small group learning in science, mathematics, engineering, and technology education is effective. Concludes that the meta-analysis' call for more widespread implementation of small group learning is not supported.…

  19. Collegiate-Based Emergency Medical Service: Impact on Alcohol-Related Emergency Department Transports at a Small Liberal Arts College

    ERIC Educational Resources Information Center

    Rosen, Joshua B.; Olson, Mark H.; Kelly, Marianne

    2012-01-01

    Objective: The authors examined the impact of a collegiate-based emergency medical service (CBEMS) on the frequency of emergency department (ED) transports. Participants: Students transported to the ED for acute alcohol intoxication during the Fall 2008 and the Fall 2009 semesters (N = 50). Methods: The frequency of students receiving…

  20. Building 211 cyclotron characterization survey report

    SciTech Connect

    1998-03-30

    The Building 211 Cyclotron Characterization Survey includes an assessment of the radioactive and chemical inventory of materials stored within the facility; an evaluation of the relative distribution of accelerator-produced activation products within various cyclotron components and adjacent structures; measurement of the radiation fields throughout the facility; measurement and assessment of internal and external radioactive surface contamination on various equipment, facility structures, and air-handling systems; and an assessment of lead (Pb) paint and asbestos hazards within the facility.

  1. The Cyclotron Production and Nuclear Imaging of BROMINE-77.

    NASA Astrophysics Data System (ADS)

    Galiano, Eduardo

    In this investigation, bromine-77 was produced with a medical cyclotron and imaged with gamma cameras. Br -77 emits a 240 kev photon with a half life of 56 hours. The C-Br bond is stronger than the C-I bond and bromine is not collected in the thyroid. Bromine can be used to label many organic molecules by methods analogous to radioiodination. The only North American source of Br-77 in the 70's and 80's was Los Alamos National Laboratory, but it discontinued production in 1989. In this method, a p,3n reaction on Br-77 produces Kr-77 which decays with a 1.2 hour half life to Br-77. A cyclotron generated 40 MeV proton beam is incident on a nearly saturated NaBr or LiBr solution contained in a copper or titanium target. A cooling chamber through which helium gas is flowed separates the solution from the cyclotron beam line. Helium gas is also flowed through the solution to extract Kr-77 gas. The mixture flows through a nitrogen trap where Kr-77 freezes and is allowed to decay to Br-77. Eight production runs were performed, three with a copper target and five with a titanium target with yields of 40, 104, 180, 679, 1080, 685, 762 and 118 uCi respectively. Gamma ray spectroscopy has shown the product to be very pure, however corrosion has been a major obstacle, causing the premature retirement of the copper target. Phantom and in-vivo rat nuclear images, and an autoradiograph in a rat are presented. The quality of the nuclear scans is reasonable and the autoradiograph reveals high isotope uptake in the renal parenchyma, a more moderate but uniform uptake in pulmonary and hepatic tissue, and low soft tissue uptake. There is no isotope uptake in the brain or the gastric mucosa.

  2. Note: Control of liquid helium supply to cryopanels of Kolkata superconducting cyclotron

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, T. K.; Pal, G.

    2015-02-01

    The Kolkata superconducting cyclotron utilises liquid helium to cool the main magnet niobium-titanium (NbTi) coil and the cryopanels. Three liquid helium cooled cryopanels, placed inside the dees of the radio-frequency system, maintain the high vacuum in the acceleration region of the superconducting cyclotron. The small cryostat placed inside the cryogenic distribution manifold located at the basement of the superconducting cyclotron building supplies liquid helium in parallel branches to three cold heads, used for cooling their associated cryopanels. The level in the cryostat has to be maintained at an optimum value to ensure uninterrupted flow of liquid helium to these three cold heads. This paper describes the transfer function of the overall system, its tuning parameters, and discusses the actual control of cryostat level by using these parameters.

  3. Note: control of liquid helium supply to cryopanels of Kolkata superconducting cyclotron.

    PubMed

    Bhattacharyya, T K; Pal, G

    2015-02-01

    The Kolkata superconducting cyclotron utilises liquid helium to cool the main magnet niobium-titanium (NbTi) coil and the cryopanels. Three liquid helium cooled cryopanels, placed inside the dees of the radio-frequency system, maintain the high vacuum in the acceleration region of the superconducting cyclotron. The small cryostat placed inside the cryogenic distribution manifold located at the basement of the superconducting cyclotron building supplies liquid helium in parallel branches to three cold heads, used for cooling their associated cryopanels. The level in the cryostat has to be maintained at an optimum value to ensure uninterrupted flow of liquid helium to these three cold heads. This paper describes the transfer function of the overall system, its tuning parameters, and discusses the actual control of cryostat level by using these parameters. PMID:25725894

  4. Note: Control of liquid helium supply to cryopanels of Kolkata superconducting cyclotron

    SciTech Connect

    Bhattacharyya, T. K. Pal, G.

    2015-02-15

    The Kolkata superconducting cyclotron utilises liquid helium to cool the main magnet niobium-titanium (NbTi) coil and the cryopanels. Three liquid helium cooled cryopanels, placed inside the dees of the radio-frequency system, maintain the high vacuum in the acceleration region of the superconducting cyclotron. The small cryostat placed inside the cryogenic distribution manifold located at the basement of the superconducting cyclotron building supplies liquid helium in parallel branches to three cold heads, used for cooling their associated cryopanels. The level in the cryostat has to be maintained at an optimum value to ensure uninterrupted flow of liquid helium to these three cold heads. This paper describes the transfer function of the overall system, its tuning parameters, and discusses the actual control of cryostat level by using these parameters.

  5. Differentiating Fragmentation Pathways of Cholesterol by Two-Dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    van Agthoven, Maria A.; Barrow, Mark P.; Chiron, Lionel; Coutouly, Marie-Aude; Kilgour, David; Wootton, Christopher A.; Wei, Juan; Soulby, Andrew; Delsuc, Marc-André; Rolando, Christian; O'Connor, Peter B.

    2015-12-01

    Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry is a data-independent analytical method that records the fragmentation patterns of all the compounds in a sample. This study shows the implementation of atmospheric pressure photoionization with two-dimensional (2D) Fourier transform ion cyclotron resonance mass spectrometry. In the resulting 2D mass spectrum, the fragmentation patterns of the radical and protonated species from cholesterol are differentiated. This study shows the use of fragment ion lines, precursor ion lines, and neutral loss lines in the 2D mass spectrum to determine fragmentation mechanisms of known compounds and to gain information on unknown ion species in the spectrum. In concert with high resolution mass spectrometry, 2D Fourier transform ion cyclotron resonance mass spectrometry can be a useful tool for the structural analysis of small molecules.

  6. An all permanent magnet electron cyclotron resonance ion source for heavy ion therapy

    NASA Astrophysics Data System (ADS)

    Cao, Yun; Li, Jia Qing; Sun, Liang Ting; Zhang, Xue Zhen; Feng, Yu Cheng; Wang, Hui; Ma, Bao Hua; Li, Xi Xia

    2014-02-01

    A high charge state all permanent Electron Cyclotron Resonance ion source, Lanzhou All Permanent ECR ion source no. 3-LAPECR3, has been successfully built at IMP in 2012, which will serve as the ion injector of the Heavy Ion Medical Machine (HIMM) project. As a commercial device, LAPECR3 features a compact structure, small size, and low cost. According to HIMM scenario more than 100 eμA of C5+ ion beam should be extracted from the ion source, and the beam emittance better than 75 π*mm*mrad. In recent commissioning, about 120 eμA of C5+ ion beam was got when work gas was CH4 while about 262 eμA of C5+ ion beam was obtained when work gas was C2H2 gas. The design and construction of the ion source and its low-energy transportation beam line, and the preliminary commissioning results will be presented in detail in this paper.

  7. An all permanent magnet electron cyclotron resonance ion source for heavy ion therapy

    SciTech Connect

    Cao, Yun Li, Jia Qing; Sun, Liang Ting; Zhang, Xue Zhen; Feng, Yu Cheng; Wang, Hui; Ma, Bao Hua; Li, Xi Xia

    2014-02-15

    A high charge state all permanent Electron Cyclotron Resonance ion source, Lanzhou All Permanent ECR ion source no. 3-LAPECR3, has been successfully built at IMP in 2012, which will serve as the ion injector of the Heavy Ion Medical Machine (HIMM) project. As a commercial device, LAPECR3 features a compact structure, small size, and low cost. According to HIMM scenario more than 100 eμA of C{sup 5+} ion beam should be extracted from the ion source, and the beam emittance better than 75 π*mm*mrad. In recent commissioning, about 120 eμA of C{sup 5+} ion beam was got when work gas was CH{sub 4} while about 262 eμA of C{sup 5+} ion beam was obtained when work gas was C{sub 2}H{sub 2} gas. The design and construction of the ion source and its low-energy transportation beam line, and the preliminary commissioning results will be presented in detail in this paper.

  8. Oak Ridge Isotope Production Cyclotron Facility and Target Handling

    SciTech Connect

    Bradley, Eric Craig; Varma, Venugopal Koikal; Egle, Brian; Binder, Jeffrey L; Mirzadeh, Saed; Tatum, B Alan; Burgess, Thomas W; Devore, Joe; Rennich, Mark; Saltmarsh, Michael John; Caldwell, Benjamin Cale

    2011-01-01

    Abstract The Nuclear Science Advisory Committee issued in August 2009 an Isotopes Subcommittee report that recommended the construction and operation of a variable-energy, high-current, multiparticle accelerator for producing medical radioisotopes. To meet the needs identified in the report, Oak Ridge National Laboratory is developing a technical concept for a commercial 70 MeV dual-port-extraction, multiparticle cyclotron to be located at the Holifield Radioactive Ion Beam Facility. The conceptual design of the isotope production facility as envisioned would provide two types of targets for use with this new cyclotron. One is a high-power target cooled by water circulating on both sides, and the other is a commercial target cooled only on one side. The isotope facility concept includes an isotope target vault for target irradiation and a shielded transfer station for radioactive target handling. The targets are irradiated in the isotope target vault. The irradiated targets are removed from the target vault and packaged in an adjoining shielded transfer station before being sent out for postprocessing. This paper describes the conceptual design of the target-handling capabilities required for dealing with these radioactive targets and for minimizing the contamination potential during operations.

  9. Emission of cyclotron radiation by interstellar planets

    NASA Astrophysics Data System (ADS)

    Vanhamäki, Heikki; Janhunen, Pekka

    We investigate the emission of cyclotron radiation by interstellar (or rogue) planets. In the solar system all planets that have significant magnetic fields also emit electron cyclotron radiation, usually near the auroral regions around the magnetic poles. Frequency and power of the emission depend on the characteristics of the planetary magnetic field and its interaction with surrounding plasma. In interstellar space the energy source for cyclotron emission is either 1) motion of the planet through the surrounding plasma or 2) unipolar induction by moons moving through co-rotating magnetospheric plasma (cf. Io and Jupiter). In the first case the kinetic and magnetic energy fluxes at the magnetopause have roughly the same order of magnitude, but the conversion rate of magnetic energy to cyclotron radiation is assumed to be higher because of the lower plasma density due to the near absence of ionospheric plasma source. Emission from the unipolar induction mechanism is assumed to be independent of the external environment. Our results indicate that a Jupiter-like planet moving through diffuse, strongly magnetized interstellar plasma at 100 km/s could emit up to 1011 W of cyclotron radiation, making the planet detectable up to a distance of one parsec with the Low Frequency Array. More massive and faster rotating planets with stronger magnetic fields could emit 10 times more at frequencies up to ˜200 MHz. For reference, a hot Jupiter orbiting close to its parent star could emit 1014 - 1015 W.

  10. Low energy cyclotron for radiocarbon dating

    SciTech Connect

    Welch, J.J.

    1984-12-01

    The measurement of naturally occurring radioisotopes whose half lives are less than a few hundred million years but more than a few years provides information about the temporal behavior of geologic and climatic processes, the temporal history of meteoritic bodies as well as the production mechanisms of these radioisotopes. A new extremely sensitive technique for measuring these radioisotopes at tandem Van de Graaff and cyclotron facilities has been very successful though the high cost and limited availability have been discouraging. We have built and tested a low energy cyclotron for radiocarbon dating similar in size to a conventional mass spectrometer. These tests clearly show that with the addition of a conventional ion source, the low energy cyclotron can perform the extremely high sensitivity /sup 14/C measurements that are now done at accelerator facilities. We found that no significant background is present when the cyclotron is tuned to accelerate /sup 14/C negative ions and the transmission efficiency is adequate to perform radiocarbon dating on milligram samples of carbon. The internal ion source used did not produce sufficient current to detect /sup 14/C directly at modern concentrations. We show how a conventional carbon negative ion source, located outside the cyclotron magnet, would produce sufficient beam and provide for quick sampling to make radiocarbon dating milligram samples with a modest laboratory instrument feasible.

  11. Results from an exploratory study to identify the factors that contribute to success for UK medical device small- and medium-sized enterprises.

    PubMed

    Hourd, P C; Williams, D J

    2008-07-01

    This paper reports the results from an exploratory study that sets out to identify and compare the strategic approaches and patterns of business practice employed by 14 UK small- and medium-sized enterprises to achieve success in the medical device sector of the health-care industry. An interview-based survey was used to construct individual case studies of the medical device technology (MDT) companies. A cross-case analysis was performed to search for patterns and themes that cut across these individual cases. Exploratory results revealed the heterogeneity of MDT companies and the distinctive features of the MDT innovation process that emphasize the importance of a strategic approach for achieving milestones in the product development and exploitation process and for creating value for the company and its stakeholders. Recognizing the heterogeneity of MDT companies, these exploratory findings call for further investigation to understand better the influence of components of the MDT innovation process on the commercialization life cycle and value trajectory. This is required to assist start-up or spin-out MDT companies in the UK and worldwide to navigate the critical transitions that determine access to financial and consumer markets and enhance the potential to build a successful business. This will be important not only for bioscience-based companies but also for engineering-based companies aiming to convert their activities into medical devices and the health- and social-care market. PMID:18756690

  12. Proton Beam Therapy for Patients With Medically Inoperable Stage I Non-Small-Cell Lung Cancer at the University of Tsukuba

    SciTech Connect

    Nakayama, Hidetsugu; Sugahara, Shinji; Tokita, Mari; Satoh, Hiroaki; Tsuboi, Koji; Ishikawa, Shigemi; Tokuuye, Koichi

    2010-10-01

    Purpose: To evaluate in a retrospective review the role of proton beam therapy for patients with medically inoperable Stage I non-small-cell lung cancer (NSCLC). Patients and Methods: From November 2001 to July 2008, 55 medically inoperable patients with Stage I NSCLC were treated with proton beam therapy. A total of 58 (T1/T2, 30/28) tumors were treated. The median age of study participants was 77 years (range, 52-86 years). A total dose of 66 GyE in 10 fractions was given to peripherally located tumors and 72.6 GyE in 22 fractions to centrally located tumors. Results: The rates (95% confidence interval) of overall and progression-free survival of all patients and of local control of all tumors at 2 years were 97.8% (93.6-102.0%), 88.7% (77.9-99.5%), and 97.0% (91.1-102.8%), respectively. There was no statistically significant difference in progression-free rate between T1 and T2 tumors (p = 0.87). Two patients (3.6%) had deterioration in pulmonary function, and 2 patients (3.6%) had Grade 3 pneumonitis. Conclusion: Proton beam therapy was effective and well tolerated in medically inoperable patients with Stage I NSCLC.

  13. Assessment of the production of medical isotopes using the Monte Carlo code FLUKA: Simulations against experimental measurements

    NASA Astrophysics Data System (ADS)

    Infantino, Angelo; Oehlke, Elisabeth; Mostacci, Domiziano; Schaffer, Paul; Trinczek, Michael; Hoehr, Cornelia

    2016-01-01

    The Monte Carlo code FLUKA is used to simulate the production of a number of positron emitting radionuclides, 18F, 13N, 94Tc, 44Sc, 68Ga, 86Y, 89Zr, 52Mn, 61Cu and 55Co, on a small medical cyclotron with a proton beam energy of 13 MeV. Experimental data collected at the TR13 cyclotron at TRIUMF agree within a factor of 0.6 ± 0.4 with the directly simulated data, except for the production of 55Co, where the simulation underestimates the experiment by a factor of 3.4 ± 0.4. The experimental data also agree within a factor of 0.8 ± 0.6 with the convolution of simulated proton fluence and cross sections from literature. Overall, this confirms the applicability of FLUKA to simulate radionuclide production at 13 MeV proton beam energy.

  14. Production of 90Y by the 90Zr (n,p)90Y reaction using neutrons produced from a variable energy cyclotron

    NASA Astrophysics Data System (ADS)

    Necsoiu, D.; Morgan, I. L.; Hupf, H.; Armbruster, J.; Boyce, D.; El Bouanani, M.; McDaniel, F. D.

    2001-07-01

    Traditionally, 90Y obtained from a 90Sr/90Y generator contains a small concentration of 90Sr (range 1 μCi 90Sr/100mCi to 1 Ci 90Y) and due to the 28.78 y half-life of 90Sr, special waste handling and storage is required. In this study, the medical isotope 90Y has been produced by an alternate method using the 90Zr(n,p)90Y reaction. Neutrons for the activation process were produced using natRh(p,xn) reaction with a 27 MeV proton beam from a cyclotron. Since 90Y is a pure beta emitter, the gamma rays from the 90Zr(n,2n)89Zr reaction were used to quantify the incident neutron flux on the 90Zr sample. Experimental results of the neutron production and 90Y activity are presented.

  15. Cost-Effectiveness Analysis of Stereotactic Body Radiotherapy and Radiofrequency Ablation for Medically Inoperable, Early-Stage Non-Small Cell Lung Cancer

    SciTech Connect

    Sher, David J.

    2011-12-01

    Purpose: The standard management of medically inoperable Stage I non-small-cell lung cancer (NSCLC) conventionally has been fractionated three-dimensional conformal radiation therapy (3D-CRT). The relatively poor local control rate and inconvenience associated with this therapy have prompted the development of stereotactic body radiotherapy (SBRT), a technique that delivers very high doses of irradiation typically over 3 to 5 sessions. Radiofrequency ablation (RFA) has also been investigated as a less costly, single-day therapy that thermally ablates small, peripheral tumors. The cost-effectiveness of these three techniques has never been compared. Methods and Materials: We developed a Markov model to describe health states of 65-year-old men with medically inoperable NSCLC after treatment with 3D-CRT, SBRT, and RFA. Given their frail state, patients were assumed to receive supportive care after recurrence. Utility values, recurrence risks, and costs were adapted from the literature. Sensitivity analyses were performed to model uncertainty in these parameters. Results: The incremental cost-effectiveness ratio for SBRT over 3D-CRT was $6,000/quality-adjusted life-year, and the incremental cost-effectiveness ratio for SBRT over RFA was $14,100/quality-adjusted life-year. One-way sensitivity analysis showed that the results were robust across a range of tumor sizes, patient utility values, and costs. This result was confirmed with probabilistic sensitivity analyses that varied local control rates and utilities. Conclusion: In comparison to 3D-CRT and RFA, SBRT was the most cost-effective treatment for medically inoperable NSCLC over a wide range of treatment and disease assumptions. On the basis of efficacy and cost, SBRT should be the primary treatment approach for this disease.

  16. Challenges for the ITER ion cyclotron system

    SciTech Connect

    Swain, D.W.; Ryan, P.M.; Taylor, D.J.; Bosia, G.

    1997-09-01

    Ion cyclotron heating is one of the methods proposed for heating and for driving current in the ITER plasma. The ITER environment is significantly different from that of present day tokamak because of heating from neutrons and from the high radiated heat flux. In addition, the proposed 15 cm gap between the plasma separatrix and the outer wall (where the ion cyclotron antennas are located) necessitates running the antennas at relatively high values of voltage in order to couple the required power to the plasma. There are two main questions: (1) Can the ion cyclotron antennas deliver the required power to the plasma? (2) Can they survive in the ITER environment? Results presented in this paper indicate that the antennas can survive both normal operation and disruptions in ITER, and can deliver the power to the plasma.

  17. Improving cancer treatment with cyclotron produced radionuclides

    SciTech Connect

    Larson, S.M. Finn, R.D.

    1992-08-04

    This report describes the author's continuing long term goal of promoting nuclear medicine applications by improving the scientific basis for tumor diagnosis treatment and treatment follow-up based on the use of cyclotron produced radiotracers in oncology. The program has 3 interactive components: Radiochemistry /Cyclotron; Pharmacology; and Immunology. An essential strategy is as follows: novel radionuclides and radiotracers developed in the Radiochemistry/Cyclotron section under the DOE grant during the 1989--1992 grant period, will be employed in the Pharmacology and Immunology sections of the DOE grant during the 1992--1995 grant period. The development of novel radionuclides and tracers is of course useful in and of itself, but their utility is greatly enhanced by the interaction with the immunology and pharmacology components of the program.

  18. 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.

  19. Residual radioactivity at the Milan AVF cyclotron

    NASA Astrophysics Data System (ADS)

    Birattari, C.; Cantone, M. C.; Ferrari, A.; Silari, M.

    1989-08-01

    γ-ray spectrometry measurements have been carried out at the Cyclotron Laboratory at the Department of Physics of the University of Milan, to evaluate the levels of residual radioactivity after about one year from shut down. Measurements were performed inside the cyclotron and at several points in the accelerator vault and target room, as well as on specific components removed from the beam transport system, on samples of the concrete shields and on residues taken from the cyclotron vacuum chamber. The radionuclides identified and the values of specific activity and dose rate are reported. The results indicate that no particular hazard and waste disposal problems should be encountered at the time of the decommissioning of the facility.

  20. 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.

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

    PubMed

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

    2014-02-01

    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. PMID:24593512

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

    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.

  3. Numerical simulations on electrostatic hydrogen cyclotron instabilities

    SciTech Connect

    Okuda, H.; Cheng, C.Z.; Lee, W.W.

    1981-02-01

    Both one- and two-dimensional particle simulation models have been used to study the nonlinear behavior of the electrostatic hydrogen cyclotron instabilities driven by the electron current along magnetic field. It is found that the instability saturates as a result of electron velocity space diffusion along magnetic field. The cyclotron waves remain highly coherent in the nonlinear stage. When the electron drift speed is comparable to thermal speed, substantial ion heating as well as particle cross-field diffusion comparable to Bohm diffusion has been observed. Comparisons of the simulation results with the theoretical predictions and the observations in both laboratory and space plasmas are discussed.

  4. Nuclear Physics at the Warsaw Cyclotron

    NASA Astrophysics Data System (ADS)

    Jastrz?bski, J.

    2009-03-01

    Commissioned in 1994, the Warsaw Cyclotron is operated by the Heavy Ion Laboratory of the University of Warsaw as a "User Facility" with around 100 national and foreign users per year. The isochronous Kmax=160 machine currently delivers around 3000 h of heavy ion beams per year, ranging from B to Ar, with energies between 2 and 10 MeV/nucleon. The current research programme comprises nuclear physics, atomic physics, materials science, solid state physics, biology, particle detector development and testing. In this article the experimental stations placed on the beam-lines of the cyclotron and some recent nuclear physics experiments are presented.

  5. Compact superconducting 250 MeV proton cyclotron for the PSI PROSCAN proton therapy project

    NASA Astrophysics Data System (ADS)

    Schillo, M.; Geisler, A.; Hobl, A.; Klein, H. U.; Krischel, D.; Meyer-Reumers, M.; Piel, C.; Blosser, H.; Kim, J.-W.; Marti, F.; Vincent, J.; Brandenburg, S.; Beijers, J. P. M.

    2001-12-01

    A cyclotron for proton therapy has to fulfill many requirements set by the specific operational and safety needs of a medical facility and the medical environment. These are for instance high extraction efficiency, high availability and reliability, simple and robust operation. ACCEL Instruments GmbH has refined the design concept of a medical cyclotron for the PSI PROSCAN project with the objective to use this cyclotron as the standard accelerator in complete proton therapy facilities, which ACCEL intends to market. Starting from the design in [1], we have carried out further detail clarifications, optimizations and adaptations to the needs of PSI [2]. The work was performed in a collaboration between ACCEL, NSCL and KVI in view of the requirements from the PSI PROSCAN project. An overview on the design will be given touching on subjects such as the 3D structural analysis of the coil, detailed magnetic modeling for optimization of the inner region and the spiral, optimization of the RF power, optimization of the cryogenic design based on available cryocoolers instead of a liquefaction plant and Monte Carlo simulations to estimate the heat balance produced by neutrons at 4K components.

  6. Ion-cyclotron instability in magnetic mirrors

    SciTech Connect

    Pearlstein, L.D.

    1987-02-02

    This report reviews the role of ion-cyclotron frequency instability in magnetic mirrors. The modes discussed here are loss-cone or anisotropy driven. The discussion includes quasilinear theory, explosive instabilities of 3-wave interaction and non-linear Landau damping, and saturation due to non-linear orbits. (JDH)

  7. Stability of the Electron Cyclotron Resonance

    NASA Astrophysics Data System (ADS)

    Asch, Joachim; Bourget, Olivier; Meresse, Cédric

    2015-12-01

    We consider the magnetic AC Stark effect for the quantum dynamics of a single particle in the plane under the influence of an oscillating homogeneous electric and a constant perpendicular magnetic field. We prove that the electron cyclotron resonance is insensitive to impurity potentials.

  8. Cyclotron drift instability in the bow shock.

    NASA Technical Reports Server (NTRS)

    Wu, C. S.; Fredricks, R. W.

    1972-01-01

    It is argued that the cyclotron drift instability (coupled ion waves and electron Bernstein modes) can explain many structural features of the weak electrostatic turbulence observed in bow shock magnetic-field gradients and thus that it provides a more attractive speculation than the ion acoustic or Buneman instabilities previously suggested as weak turbulence sources.

  9. 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.

  10. Physics of Cyclotron Resonance Scattering Features

    NASA Astrophysics Data System (ADS)

    Sschoenherr, Gabriele; Schwarm, Fritz-Walter; Falkner, Sebastian; Dauser, Thomas; Pottschmidt, Katja; Kretschmar, Peter; Klochkov, Dmitry; Ferrigno, Carlo; Britton Hemphill, Paul; Wilms, Joern

    2016-04-01

    Cyclotron resonant scattering features (short: cyclotron lines) are sensitive tracers of the physics of the accretion columns and mounds of X-ray pulsars. They form by interaction of X-ray photons with magnetically quantized electrons in the accreted plasma close to the neutron star. Such lines have been observed as absorption-like features for about 20 X-ray pulsars. Their energies provide a direct measure of the magnetic field strength in the line-forming region. By detailed modelling of the lines and of their parameter dependencies we can further decipher the physical conditions in the accretion column. For instance the fact that the complex scattering cross sections have a strong angle-dependence relates the phase-resolved cyclotron line shapes to parameters that constrain the systems’ still poorly understood geometry. Modelling the physics of cyclotron lines to a degree that allows for detailed and solid comparison to data therefore provides a unique access also to a better understanding of the overall picture of magnetically accreting neutron star systems.

  11. Cyclotron-based neutron source for BNCT

    SciTech Connect

    Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K.; Tanaka, H.; Sakurai, Y.; Maruhashi, A.

    2013-04-19

    Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation and treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8 Multiplication-Sign 109 neutrons/cm{sup 2}/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with {sup 10}B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.

  12. On Resonant Heating Below the Cyclotron Frequency

    SciTech Connect

    Liu Chen; Zhihong Lin; White, R.

    2001-02-02

    Resonant heating of particles by an electrostatic wave propagating perpendicular to a confining uniform magnetic field is examined. It is shown that, with a sufficiently large wave amplitude, significant perpendicular stochastic heating can be obtained with wave frequency at a fraction of the cyclotron frequency.

  13. Electric-field ion cyclotron resonance

    SciTech Connect

    Liboff, A.R.

    1997-03-01

    The authors consider the possibility that DC magnetic fields can interact in a resonant manner with endogenous AC electric fields in biological systems. Intrinsic electric-field ion cyclotron resonance (ICR) interactions would be more physically credible than models based on external AC magnetic fields and might be expected as an evolutionary response to the long-term constancy of the geomagnetic field.

  14. Imaging Cyclotron Orbits of Electrons in Graphene.

    PubMed

    Bhandari, Sagar; Lee, Gil-Ho; Klales, Anna; Watanabe, Kenji; Taniguchi, Takashi; Heller, Eric; Kim, Philip; Westervelt, Robert M

    2016-03-01

    Electrons in graphene can travel for several microns without scattering at low temperatures, and their motion becomes ballistic, following classical trajectories. When a magnetic field B is applied perpendicular to the plane, electrons follow cyclotron orbits. Magnetic focusing occurs when electrons injected from one narrow contact focus onto a second contact located an integer number of cyclotron diameters away. By tuning the magnetic field B and electron density n in the graphene layer, we observe magnetic focusing peaks. We use a cooled scanning gate microscope to image cyclotron trajectories in graphene at 4.2 K. The tip creates a local change in density that casts a shadow by deflecting electrons flowing nearby; an image of flow can be obtained by measuring the transmission between contacts as the tip is raster scanned across the sample. On the first magnetic focusing peak, we image a cyclotron orbit that extends from one contact to the other. In addition, we study the geometry of orbits deflected into the second point contact by the tip. PMID:26845290

  15. Cyclotron-based neutron source for BNCT

    NASA Astrophysics Data System (ADS)

    Mitsumoto, T.; Yajima, S.; Tsutsui, H.; Ogasawara, T.; Fujita, K.; Tanaka, H.; Sakurai, Y.; Maruhashi, A.

    2013-04-01

    Kyoto University Research Reactor Institute (KURRI) and Sumitomo Heavy Industries, Ltd. (SHI) have developed a cyclotron-based neutron source for Boron Neutron Capture Therapy (BNCT). It was installed at KURRI in Osaka prefecture. The neutron source consists of a proton cyclotron named HM-30, a beam transport system and an irradiation & treatment system. In the cyclotron, H- ions are accelerated and extracted as 30 MeV proton beams of 1 mA. The proton beams is transported to the neutron production target made by a beryllium plate. Emitted neutrons are moderated by lead, iron, aluminum and calcium fluoride. The aperture diameter of neutron collimator is in the range from 100 mm to 250 mm. The peak neutron flux in the water phantom is 1.8×109 neutrons/cm2/sec at 20 mm from the surface at 1 mA proton beam. The neutron source have been stably operated for 3 years with 30 kW proton beam. Various pre-clinical tests including animal tests have been done by using the cyclotron-based neutron source with 10B-p-Borono-phenylalanine. Clinical trials of malignant brain tumors will be started in this year.

  16. Toxicity and Patterns of Failure of Adaptive/Ablative Proton Therapy for Early-Stage, Medically Inoperable Non-Small Cell Lung Cancer

    SciTech Connect

    Chang, Joe Y.; Komaki, Ritsuko; Wen, Hong Y.; De Gracia, Beth; Bluett, Jaques B.; McAleer, Mary F.; Swisher, Stephen G.; Cox, James D.

    2011-08-01

    Purpose: To analyze the toxicity and patterns of failure of proton therapy given in ablative doses for medically inoperable early-stage non-small cell lung cancer (NSCLC). Methods and Materials: Eighteen patients with medically inoperable T1N0M0 (central location) or T2-3N0M0 (any location) NSCLC were treated with proton therapy at 87.5 Gy (relative biological effectiveness) at 2.5 Gy /fraction in this Phase I/II study. All patients underwent treatment simulation with four-dimensional CT; internal gross tumor volumes were delineated on maximal intensity projection images and modified by visual verification of the target volume in 10 breathing phases. The internal gross tumor volumes with maximal intensity projection density was used to design compensators and apertures to account for tumor motion. Therapy consisted of passively scattered protons. All patients underwent repeat four-dimensional CT simulations during treatment to assess the need for adaptive replanning. Results: At a median follow-up time of 16.3 months (range, 4.8-36.3 months), no patient had experienced Grade 4 or 5 toxicity. The most common adverse effect was dermatitis (Grade 2, 67%; Grade 3, 17%), followed by Grade 2 fatigue (44%), Grade 2 pneumonitis (11%), Grade 2 esophagitis (6%), and Grade 2 chest wall pain (6%). Rates of local control were 88.9%, regional lymph node failure 11.1%, and distant metastasis 27.8%. Twelve patients (67%) were still alive at the last follow-up; five had died of metastatic disease and one of preexisting cardiac disease. Conclusions: Proton therapy to ablative doses is well tolerated and produces promising local control rates for medically inoperable early-stage NSCLC.

  17. Use of modified SOAP notes and peer-led small-group discussion in a Medical Physiology course: addressing the hidden curriculum.

    PubMed

    Kibble, Jonathan; Hansen, Penelope A; Nelson, Loren

    2006-12-01

    Peer leading of small-group discussion of cases; use of modified subjective, objective, assessment of physiology (SOAP) notes; and opportunities for self-assessment were introduced into a Medical Physiology course to increase students' awareness and practice of professional behaviors. These changes arose from faculty members' understanding of the hidden curriculum and their efforts to reveal it to take increased advantage of its educationally beneficial aspects. Faculty members and students observed that the requirement for students to submit SOAP notes before their discussions meant that they were well prepared to participate. Student satisfaction with the protocol was high, with >95% of the students agreeing that discussants were well prepared and that the overall performance of their discussion group was good. A comparison of students' performance on selected exam questions showed that peer leading was equally as effective as a previously used teacher-centered approach. Students agreed that their ability to analyze a clinical case had improved using this protocol, an effect that persisted at least one semester after the end of the course. These approaches were time and cost efficient from a faculty perspective while serving the needs of the students. The use of SOAP notes and peer-led discussion were effective forms of instruction, in which students succeeded in learning medical physiology and in practicing professional behaviors. PMID:17108251

  18. Medical Students' Attitudes Toward Non-Adherent Patients Before and After a Simulated Patient-Role Activity and Small-Group Discussion: Revisited

    PubMed Central

    Giordano, Christin; Castiglioni, Analia; Hernandez, Caridad

    2016-01-01

    Introduction This study seeks to explore whether the documented decline in medical student empathy can be prevented or slowed using simulated patient-role activities and small-group discussions about the patient experience of living with a chronic illness. Methods First-year students (M1, n = 118) at the University of Central Florida College of Medicine (UCFCOM) participated in a simulated patient-role activity resembling the experience of a patient with Type 2 diabetes mellitus. The activity included taking daily “medication,” participating in moderate exercise, and maintaining a low carbohydrate diet. At the end of the simulated patient-role activity, students took part in a small-group discussion about their experiences. Students completed the Jefferson Scale of Physician Empathy: Student Version (JSPE:S) before and after the activity. Additionally, fourth-year students (M4) at UCFCOM completed the JSPE:S to serve as the control, as this class completed the curriculum without any simulated patient-role activities. Results A total of 86 responses out of 118 possible M1 participants (73% response rate) were received. Of these, 62 surveys were completed and were therefore used for statistical analysis. A dependent sample t-test revealed no statistically significant increase on pre-activity (M = 111.15, SD = 8.56) and post-activity (M = 111.38, SD = 9.12) empathy scores (p = .78). A positive correlation was revealed to exist between pre- and post-activity empathy scores (r = 0.72, p < 0.001). Empathy comparisons for the full sample M1 post-activity results (n = 62) and the M4 results (n = 16, M = 106.56, SD = 10.61) revealed no statistically significant difference (p = .11). Discussion Although previous authors have shown that patient role-playing activities, such as those performed in this study, should maintain and/or increase empathy in medical students, our findings suggest that on a short-term scale, empathy levels were not affected by the activity. PMID:27226937

  19. Optimization of A Commercial PET Cyclotron For Increased 18F- Production

    NASA Astrophysics Data System (ADS)

    Bergstrom, Jan Olof; Eriksson, Tomas

    2003-08-01

    Commercial cyclotron systems used for 18F- production through 18O (p, n) 18F reaction face several conflicting requirements that include: reliability/uptime, quantity of consumables, safety, cost and yield. With commercialization of PET tracer distribution, higher yield has become one of the most important requirements. Maximizing yield for commercial cyclotrons require engineering trade-off amongst several requirements, and often, to be conservative, significant design margin is kept while field feedback is collected. With maturing of technology, substantial experience has been obtained for a commercial cyclotron (PETtrace, GE Medical Systems), which is in use for several years. In this paper, we describe key elements of PETtrace commercial cyclotron technology undergoing enhancements, and share our works-in-progress experiments in performing critical engineering trade-offs to improve 18F- yield. Three key parameters were tuned in this study within the design margin of the current equipment. First, we designed a second-generation target assembly with optimized 18O water volume for accepting increased beam currents while maintaining cooling performance. Second, we increased the beam current of the ion source. And finally, a new RF driver amplifier was designed to enhance the RF power ratings to enable higher beam currents. Initial tests performed in the factory indicate substantially higher yield performance (> 50%) reaching a peak yield of over 4 Ci per hour of bombardment in the new target. On dual targets, this extrapolates to 13.5 Ci/2hr of bombardment for a total target current of 120 μA. A target current of 100 μA is available in the existing design thus providing an 18F- production capacity exceeding 11 Ci/2hr. The preliminary experimental results are promising and illustrate successful exploitation of design margin to achieve increased yield for a commercial cyclotron. Long-term studies to assess impact on life of ion source are underway along with a dedicated effort for achieving target currents in the excess of 120μA.

  20. Development of Cyclotron Beam Technology for Applications in Materials Science and Biotechnology at JAERI-TIARA

    SciTech Connect

    Ohara, Y.; Arakawa, K.; Fukuda, M.; Kamiya, T.; Kurashima, S.; Nakamura, Y.; Okumura, S.; Saidoh, M.; Tajima, S.

    2003-08-26

    Recent progress of cyclotron ion beam development for applications in materials science and biotechnology at the ion-irradiation research facility TIARA of the Japan Atomic Energy Research Institute(JAERI) is overviewed. The AVF cyclotron in TIARA can accelerate protons and heavy ions up to 90 MeV and 27.5 MeV/n, respectively. In order to conform to the requirement of a reliable tuning of microbeam formation, the cyclotron beam current has been stabilized by controlling the temperature of the magnet yoke and pole within +/-0.5 deg. and hence by decreasing the variation of the magnetic field {delta}B/B below 10-5. A heavy ion microbeam with energy of hundreds MeV is a significantly useful probe for researches on biofunctional elucidation in biotechnology. Production of the microbeam with spot size as small as 1{mu}m by quadrupole lenses requires the energy spread of the beam {delta}E/E < 2 x 10-4. In order to minimize the energy spread of the cyclotron beam, the fifth-harmonic voltage waveform has been successfully superposed on the fundamental one to make energy gain uniform.

  1. Design study of a 9 MeV compact cyclotron system for PET

    NASA Astrophysics Data System (ADS)

    Lee, Byeong-No; Shin, Seung-Wook; Song, Hoseung; Kim, Hyun-Wook; Chai, Jong-Seo

    2013-06-01

    A cyclotron is an accelerator which can be applied to both cancer diagnosis and treatment. Among commercially sold cyclotrons, the major energy is used for positron emission tomography (PET) ranges from 10 to 20 MeV. In this research, 9 MeV compact cyclotron for PET was designed. The research was conducted on the response cross section and the yield for the energy distribution to decide the design features. Also, it was determined the specifications on the basis of the fluoro-deoxy-glucose (FDG) maximum dose. The machine, which has a 20 uA beam current, is designed to be installed in small-to-medium-sized hospitals in local cities because of its relatively light weight (6 tons). This compact cyclotron, which provides 9-MeV proton beams, is composed of a azimuthally varying field (AVF) electromagnet, 83-MHz RF systems with a 20 kW amplifier, a panning ion gauge (PIG) type ion-source for negative hydrogen, and a double-stage high-vacuum system. The basic model design was done by using 3-D CAD program, CATIA and all the field calculations were performed using commercial electromagnetic field analysis code, OPERA-3D TOSCA. From this research, we expect a time reduction for FDG production, a decrease of radioactive exposure for workers, and an equipment cost reduction.

  2. Ion cyclotron heating experiments in EBT-S

    SciTech Connect

    Baity, F.W.; Davis, W.A.; Eldridge, O.C.; Glowienka, J.C.; Hillis, D.L.; Rasmussen, D.A.; Richards, R.K.; Mullen, J.H.; Owens, T.L.

    1982-01-01

    Fast-wave heating and propagation experiments in the ion cyclotron range of frequencies (ICRF) have been carried out on EBT-S under steady-state conditions at power levels up to 20 kW and under pulsed conditions at power levels up to 100 kW. The waves were launched using a single Faraday-shielded loop antenna installed on the midplane of one of the 24 cavity sectors. Substantial ion heating was observed at frequencies above the second harmonic for hydrogen plasmas and at frequencies above the third harmonic for deuterium plasmas, corresponding with the onset of wave propagation around the torus. The heating under these conditions is anomalous. In the case of deuterium plasmas, a small residual concentration (2 to 5%) of hydrogen was heated, but this component did not appear to affect the deuterium heating.

  3. Resonance of relativistic electrons with electromagnetic ion cyclotron waves

    DOE PAGESBeta

    Denton, R. E.; Jordanova, V. K.; Bortnik, J.

    2015-06-29

    Relativistic electrons have been thought to more easily resonate with electromagnetic ion cyclotron EMIC waves if the total density is large. We show that, for a particular EMIC mode, this dependence is weak due to the dependence of the wave frequency and wave vector on the density. A significant increase in relativistic electron minimum resonant energy might occur for the H band EMIC mode only for small density, but no changes in parameters significantly decrease the minimum resonant energy from a nominal value. The minimum resonant energy depends most strongly on the thermal velocity associated with the field line motionmore » of the hot ring current protons that drive the instability. High density due to a plasmasphere or plasmaspheric plume could possibly lead to lower minimum resonance energy by causing the He band EMIC mode to be dominant. We demonstrate these points using parameters from a ring current simulation.« less

  4. Resonance of relativistic electrons with electromagnetic ion cyclotron waves

    SciTech Connect

    Denton, R. E.; Jordanova, V. K.; Bortnik, J.

    2015-06-29

    Relativistic electrons have been thought to more easily resonate with electromagnetic ion cyclotron EMIC waves if the total density is large. We show that, for a particular EMIC mode, this dependence is weak due to the dependence of the wave frequency and wave vector on the density. A significant increase in relativistic electron minimum resonant energy might occur for the H band EMIC mode only for small density, but no changes in parameters significantly decrease the minimum resonant energy from a nominal value. The minimum resonant energy depends most strongly on the thermal velocity associated with the field line motion of the hot ring current protons that drive the instability. High density due to a plasmasphere or plasmaspheric plume could possibly lead to lower minimum resonance energy by causing the He band EMIC mode to be dominant. We demonstrate these points using parameters from a ring current simulation.

  5. Electron-cyclotron wave scattering by edge density fluctuations in ITER

    SciTech Connect

    Tsironis, Christos; Peeters, Arthur G.; Isliker, Heinz; Chatziantonaki, Ioanna; Vlahos, Loukas; Strintzi, Dafni

    2009-11-15

    The effect of edge turbulence on the electron-cyclotron wave propagation in ITER is investigated with emphasis on wave scattering, beam broadening, and its influence on localized heating and current drive. A wave used for electron-cyclotron current drive (ECCD) must cross the edge of the plasma, where density fluctuations can be large enough to bring on wave scattering. The scattering angle due to the density fluctuations is small, but the beam propagates over a distance of several meters up to the resonance layer and even small angle scattering leads to a deviation of several centimeters at the deposition location. Since the localization of ECCD is crucial for the control of neoclassical tearing modes, this issue is of great importance to the ITER design. The wave scattering process is described on the basis of a Fokker-Planck equation, where the diffusion coefficient is calculated analytically as well as computed numerically using a ray tracing code.

  6. Neutron spectrometry in a PET cyclotron with a Bonner sphere system.

    PubMed

    Fernández, F; Amgarou, K; Domingo, C; García, M J; Quincoces, G; Martí-Climent, J M; Méndez, R; Barquero, R

    2007-01-01

    Positron emission tomography (PET) is a non-invasive medical imaging technique normally used for diagnostic purposes to determine the location and concentration of physiologically active compounds in a human body. An unshielded cyclotron is used for PET at the Clinica Universitaria de Navarra to produce short-lived positron emitting radionuclides ((15)O, (13)N, (11)C and (18)F) by bombarding appropriate target material with proton or deuteron beams with energies up to 18 and 9 MeV, respectively. Subsequent nuclear reactions may generate undesirable neutrons that should be evaluated and controlled. In this study, the neutron measurements performed with an active and a passive Bonner sphere systems at different locations outside and inside the cyclotron vault during operation have been presented. The neutron spectrum at each location was determined with an unfolding code developed by the authors. PMID:17575290

  7. Electrostatic ion cyclotron velocity shear instability

    NASA Technical Reports Server (NTRS)

    Lemons, D. S.; Winske, D.; Gary, S. P.

    1992-01-01

    A local electrostatic dispersion equation is derived for a shear flow perpendicular to an ambient magnetic field, which includes all kinetic effects and involves only one important parameter. The dispersion equation is cast in the form of Gordeyev integrals and is solved numerically. Numerical solutions indicate that an ion cyclotron instability is excited. The instability occurs roughly at multiples of the ion cyclotron frequency (modified by the shear), with the growth rate or the individual harmonics overlapping in the wavenumber. At large values of the shear parameter, the instability is confined to long wavelengths, but at smaller shear, a second distinct branch at shorter wavelengths also appears. The properties of the instability obtained are compared with those obtained in the nonlocal limit by Ganguli et al. (1985, 1988).

  8. Orbit correction in an orbit separated cyclotron

    NASA Astrophysics Data System (ADS)

    Plostinar, C.; Rees, G. H.

    2014-04-01

    The orbit separated proton cyclotron (OSC) described in [1] differs in concept from that of a separated orbit cyclotron (SOC) [2]. Synchronous acceleration in an OSC is based on harmonic number jumps and orbit length adjustments via reverse bending. Four-turn acceleration in the OSC enables it to have four times fewer cryogenic-cavity systems than in a superconducting linac of the same high beam power and energy range. Initial OSC studies identified a progressive distortion of the spiral beam orbits by the off-axis, transverse deflecting fields in its accelerating cavities. Compensation of the effects of these fields involves the repeated use of a cavity field map, in a 3-D linac tracking code, to determine the modified arc bends required for the OSC ring. Subsequent tracking studies confirm the compensation scheme and show low emittance growth in acceleration.

  9. Dipole moments of HCO+ and NH+ from cyclotron frequency polarizability shifts

    NASA Astrophysics Data System (ADS)

    Mount, Brianna J.; Redshaw, Matthew; Myers, Edmund G.

    2012-01-01

    Using single ions in a precision cryogenic Penning trap and by measuring the small shifts in their cyclotron frequencies due to their electric polarizability, the ground-state electric dipole moments of HCO+ and NH+ have been determined. The results are μ(HCO+) = 1.543(12) ea0 and μ(NH+) = 0.782(11) ea0, which agree with theoretical predictions.

  10. Electron cyclotron emission imaging diagnostic on TEXTOR

    SciTech Connect

    Deng, B. H.; Domier, C. W.; Luhmann, N. C.; Donne, A. J. H.; van de Pol, M. J.

    2001-01-01

    A 16-channel electron cyclotron emission imaging diagnostic system, developed by UC Davis in collaboration with the FOM-Instituut voor Plasmafysica Rijnhuizen, has been installed on the Torus Experiment for Technology Oriented Research tokamak. The system is designed to collect multichannel electron temperature profile and fluctuation data along a vertical chord of constant magnetic field, by collecting second harmonic X-mode emission. Technical details of the system are presented together with preliminary experimental data.

  11. ITER Ion Cyclotron Heating and Fueling Systems

    SciTech Connect

    Rasmussen, D.A.; Baylor, L.R.; Combs, S.K.; Fredd, E.; Goulding, R.H.; Hosea, J.; Swain, D.W.

    2005-04-15

    The ITER burning plasma and advanced operating regimes require robust and reliable heating and current drive and fueling systems. The ITER design documents describe the requirements and reference designs for the ion cyclotron and pellet fueling systems. Development and testing programs are required to optimize, validate and qualify these systems for installation on ITER.The ITER ion cyclotron system offers significant technology challenges. The antenna must operate in a nuclear environment and withstand heat loads and disruption forces beyond present-day designs. It must operate for long pulse lengths and be highly reliable, delivering power to a plasma load with properties that will change throughout the discharge. The ITER ion cyclotron system consists of one eight-strap antenna, eight rf sources (20 MW, 35-65 MHz), associated high-voltage DC power supplies, transmission lines and matching and decoupling components.The ITER fueling system consists of a gas injection system and multiple pellet injectors for edge fueling and deep core fueling. Pellet injection will be the primary ITER fuel delivery system. The fueling requirements will require significant extensions in pellet injector pulse length ({approx}3000 s), throughput (400 torr-L/s,) and reliability. The proposed design is based on a centrifuge accelerator fed by a continuous screw extruder. Inner wall pellet injection with the use of curved guide tubes will be utilized for deep fueling.

  12. Transparency of Magnetized Plasma at Cyclotron Frequency

    SciTech Connect

    G. Shvets; J.S. Wurtele

    2002-03-14

    Electromagnetic radiation is strongly absorbed by a magnetized plasma if the radiation frequency equals the cyclotron frequency of plasma electrons. It is demonstrated that absorption can be completely canceled in the presence of a magnetostatic field of an undulator or a second radiation beam, resulting in plasma transparency at the cyclotron frequency. This effect is reminiscent of the electromagnetically induced transparency (EIT) of the three-level atomic systems, except that it occurs in a completely classical plasma. Unlike the atomic systems, where all the excited levels required for EIT exist in each atom, this classical EIT requires the excitation of the nonlocal plasma oscillation. The complexity of the plasma system results in an index of refraction at the cyclotron frequency that differs from unity. Lagrangian description was used to elucidate the physics and enable numerical simulation of the plasma transparency and control of group and phase velocity. This control naturally leads to applications for electromagnetic pulse compression in the plasma and electron/ion acceleration.

  13. Operation of a quasioptical electron cyclotron maser

    SciTech Connect

    Morse, E.C.; Pyle, R.V.

    1984-12-01

    The electron cyclotron maser or gyrotron concept has been developed to produce sources producing 200 kW at 28 GHz continuously, and higher power outputs and frequencies in pulsed mode. These sources have been useful in electron cyclotron resonance heating (ECRH) in magnetically confined fusion devices. However, higher frequencies and higher power levels will be required in reactor-grade fusion plasmas, with likely requirements of 1.0 MW or more per source at 140 GHz. Conventional gyrotrons follow a trend of decreasing power for increasing frequency. In order to circumvent this problem, the quasioptical electron cyclotron maser was proposed. In this device, the closed resonator of the conventional gyrotron is replaced with an open, Fabry-Perot type resonator. The cavity modes are then the TEM-type modes of an optical laser. The advantage of this configuration is that the cavity size is not a function of frequency, since the length can be any half-integer number of wavelengths. Furthermore, the beam traverses across the cavity transverse to the direction of radiation output, and thus the rf window design is less complicated than in conventional tubes. The rf output, if obtained by diffraction coupling around one of the mirrors, could be in a TEM mode, which would allow for quasioptical transmission of the microwaves into the plasma in fusion devices. 4 references, 1 figure.

  14. Emission of cyclotron radiation by interstellar planets

    NASA Astrophysics Data System (ADS)

    Vanhamäki, H.

    2011-07-01

    In the solar system all planets that have significant magnetic fields also emit electron cyclotron radiation, usually near the auroral regions around the magnetic poles. In this study we use scaling laws based on solar system data to estimate the power and frequency of the auroral cyclotron emissions from interstellar planets (or sub-brown dwarfs). The emission can be powered either by motion of the planet through the interstellar plasma or by unipolar induction due to a moon. According to our results, in interstellar space the unipolar induction mechanism is potentially more effective than the motional emission mechanism. Typical emission power is around 10 10-10 12 W, but significantly stronger emissions are obtained in the most optimistic estimates. We have to conclude that detection of a rogue Jupiter would be very difficult, if not impossible with the radio telescopes available now or in the near future, but in very favorable conditions a much more massive and rapidly rotating (or otherwise strongly magnetized) gas giant with a large nearby moon could be detected up to ˜57 pc distance with the square kilometer array. There may be a few thousand large enough interstellar planets this close to the solar system. For reference, we point out that according to previous studies some known hot Jupiters are expected to emit up to 10 14-10 16 W of cyclotron radiation, orders of magnitude more than the typical interstellar planets discussed here. However, these emissions have not yet been detected.

  15. The Evergreen State College Cyclotron Project

    NASA Astrophysics Data System (ADS)

    Small, Christopher; Dhillon, Amandeep; Lessard, Paul

    2006-05-01

    We have designed a cyclotron device capable of performing a variety of experiments. The first stage in our construction is to make our device useable as a FT-ICR spectrometer. To this end we shall mount an array of induction coils to the floor of the orbit chamber to monitor ions. Applying the Fourier transform to the signal from this array will yield the cyclotron frequencies of all species orbiting in the chamber. From these frequencies, and their corresponding amplitudes, we can determine the charge to mass ratio and relative abundance of species in our sample. We will use the device to perform radio isotopic dating, beginning with carbon 14 dating, as a measure of our device's accuracy. During the second stage we will install an exit port for an accelerated particle beam. We have designed a new beam extraction method that may better suit our particular application than the standard methods. At this stage we will use the signal coming from the induction array to determine the frequency at which we should switch the potential between the cyclotron chamber halves. This allows us to synchronize the accelerating voltage and the particle's orbit in such a way that we can effectively accelerate particles to relativistic speeds.

  16. Improving cancer treatment with cyclotron produced radionuclides

    SciTech Connect

    Larson, S.M.; Finn, R.D.

    1992-08-04

    Our goal is to improve the scientific basis for tumor diagnosis, treatment and treatment follow-up based on the use of cyclotron produced radiotracers in oncology. The grant includes 3 interactive components: Radiochemistry/Cyclotron; Pharmacology; and Immunology. The radiochemistry group seeks to develop innovative cyclotron targetry, radiopharmaceuticals, and radiolabeled antibodies, which are then used to assess important unanswered questions in tumor pharmacology and immunology. Examples include selected positron emitting radionuclides, such as Iodine-124, and Ga-66; I-124, I-123, I-131 labeled iododeoxyuridine, C-11 colchicine, and antimetabolites, like C-11 methotrexate; and radiolabeled antibodies, 3F8, M195, A33, and MRK16 for application in the pharmacology and immunology projects. The pharmacology program studies tumor resistance to chemotherapy, particularly the phenomenon of multidrug resistance and the relationship between tumor uptake and retention and the tumor response for anti-metabolite drugs. The immunology program studies the physiology of antibody localization at the tissue level as the basis for novel approaches to improving tumor localization such as through the use of an artificial lymphatic system which mechanically reduces intratumoral pressures in tumors in vivo. Quantitative imaging approaches based on PET and SPECT in radioimmunotherapy are studied to give greater insight into the physiology of tumor localization and dosimetry.

  17. The Impact of Tumor Size on Outcomes After Stereotactic Body Radiation Therapy for Medically Inoperable Early-Stage Non-Small Cell Lung Cancer

    SciTech Connect

    Allibhai, Zishan; Taremi, Mojgan; Bezjak, Andrea; Brade, Anthony; Hope, Andrew J.; Sun, Alexander; Cho, B.C. John

    2013-12-01

    Purpose: Stereotactic body radiation therapy for medically inoperable early-stage non-small cell lung cancer (NSCLC) offers excellent control rates. Most published series deal mainly with small (usually <4 cm), peripheral, solitary tumors. Larger tumors are associated with poorer outcomes (ie, lower control rates, higher toxicity) when treated with conventional RT. It is unclear whether SBRT is sufficiently potent to control these larger tumors. We therefore evaluated and examined the influence of tumor size on treatment outcomes after SBRT. Methods and Materials: Between October 2004 and October 2010, 185 medically inoperable patients with early (T1-T2N0M0) NSCLC were treated on a prospective research ethics board-approved single-institution protocol. Prescription doses were risk-adapted based on tumor size and location. Follow-up included prospective assessment of toxicity (as per Common Terminology Criteria for Adverse Events, version 3.0) and serial computed tomography scans. Patterns of failure, toxicity, and survival outcomes were calculated using Kaplan-Meier method, and the significance of tumor size (diameter, volume) with respect to patient, treatment, and tumor factors was tested. Results: Median follow-up was 15.2 months. Tumor size was not associated with local failure but was associated with regional failure (P=.011) and distant failure (P=.021). Poorer overall survival (P=.001), disease-free survival (P=.001), and cause-specific survival (P=.005) were also significantly associated with tumor size (with tumor volume more significant than diameter). Gross tumor volume and planning target volume were significantly associated with grade 2 or worse radiation pneumonitis. However, overall rates of grade ≥3 pneumonitis were low and not significantly affected by tumor or target size. Conclusions: Currently employed stereotactic body radiation therapy dose regimens can provide safe effective local therapy even for larger solitary NSCLC tumors (up to 5.7 cm in tumor diameter or 100 cm{sup 3} in tumor volume) but are associated with more nonlocal failures as well as poorer survival. These observations suggest these patients may benefit from more extensive staging or consideration of adjuvant therapy.

  18. Lack of independent effect of type 2 diabetes beyond characteristic comorbidities and medications on small muscle mass exercising muscle blood flow and exercise tolerance

    PubMed Central

    Poitras, Veronica J; Bentley, Robert F; Hopkins-Rosseel, Diana H; LaHaye, Stephen A; Tschakovsky, Michael E

    2015-01-01

    Persons with type 2 diabetes (T2D) are believed to have reduced exercise tolerance; this may be partly due to impaired exercising muscle blood flow (MBF). Whether there is an impact of T2D on exercising MBF within the typical constellation of comorbidities (hypertension, dyslipidemia, obesity) and their associated medications has not been investigated. We tested the hypothesis that small muscle mass exercise tolerance is reduced in persons with T2D versus Controls (matched for age, body mass index, fitness, comorbidities, non-T2D medications) and that this is related to blunted MBF. Eight persons with T2D and eight controls completed a forearm critical force (fCFimpulse) test as a measure of exercise tolerance (10-min intermittent maximal effort forearm contractions; the average contraction impulse in the last 30 sec quantified fCFimpulse). Forearm blood flow (FBF; ultrasound) and mean arterial pressure (MAP; finger photoplethysmography) were measured; forearm vascular conductance (FVK) was calculated. Data are means ± SD, T2D versus Control. fCFimpulse was not different between groups (136.9 ± 47.3  N·sec vs. 163.1 ± 49.7 N·sec, P = 0.371) nor was the ΔFBF from rest to during exercise at fCFimpulse (502.9 ± 144.6 vs. 709.1 ± 289.2 mL/min, P = 0.092), or its determinants ΔFVK and ΔMAP (both P > 0.05), although there was considerable interindividual variability. ΔFBF was strongly related to fCFimpulse (r = 0.727, P = 0.002), providing support for the relationship between oxygen delivery and exercise tolerance. We conclude that small muscle mass exercising MBF and exercise tolerance are not impaired in representative persons with T2D versus appropriately matched controls. This suggests that peripheral vascular control impairment does not contribute to reduced exercise tolerance in this population. PMID:26265750

  19. ENSEMBLE SIMULATIONS OF PROTON HEATING IN THE SOLAR WIND VIA TURBULENCE AND ION CYCLOTRON RESONANCE

    SciTech Connect

    Cranmer, Steven R.

    2014-07-01

    Protons in the solar corona and heliosphere exhibit anisotropic velocity distributions, violation of magnetic moment conservation, and a general lack of thermal equilibrium with the other particle species. There is no agreement about the identity of the physical processes that energize non-Maxwellian protons in the solar wind, but a traditional favorite has been the dissipation of ion cyclotron resonant Alfvén waves. This paper presents kinetic models of how ion cyclotron waves heat protons on their journey from the corona to interplanetary space. It also derives a wide range of new solutions for the relevant dispersion relations, marginal stability boundaries, and nonresonant velocity-space diffusion rates. A phenomenological model containing both cyclotron damping and turbulent cascade is constructed to explain the suppression of proton heating at low alpha-proton differential flow speeds. These effects are implemented in a large-scale model of proton thermal evolution from the corona to 1 AU. A Monte Carlo ensemble of realistic wind speeds, densities, magnetic field strengths, and heating rates produces a filled region of parameter space (in a plane described by the parallel plasma beta and the proton temperature anisotropy ratio) similar to what is measured. The high-beta edges of this filled region are governed by plasma instabilities and strong heating rates. The low-beta edges correspond to weaker proton heating and a range of relative contributions from cyclotron resonance. On balance, the models are consistent with other studies that find only a small fraction of the turbulent power spectrum needs to consist of ion cyclotron waves.

  20. Accelerator Science and Technology in Canada — From the Microtron to TRIUMF, Superconducting Cyclotrons and the Canadian Light Source

    NASA Astrophysics Data System (ADS)

    Craddock, M. K.; Laxdal, R. E.

    As elsewhere, accelerators in Canada have evolved from modest beginnings to major facilities such as TRIUMF (currently with the highest-power driver for rare isotope beam production) and the third generation Canadian Light Source. Highlights along the way include construction of the first microtron, the first racetrack microtron and the first superconducting cyclotron (to which list might have been added the first pulse stretcher ring, had it been funded sooner). This article will summarize the history of accelerators in Canada, documenting both the successes and the near-misses. Besides the research accelerators, a thriving commercial sector has developed, manufacturing small cyclotrons and linacs, beam line components and superconducting rf cavities.

  1. Accelerator Science and Technology in Canada -- From the Microtron to TRIUMF, Superconducting Cyclotrons and the Canadian Light Source

    NASA Astrophysics Data System (ADS)

    Craddock, M. K.; Laxdal, R. E.

    As elsewhere, accelerators in Canada have evolved from modest beginnings to major facilities such as TRIUMF (currently with the highest-power driver for rare isotope beam production) and the third generation Canadian Light Source. Highlights along the way include construction of the first microtron, the first racetrack microtron and the first superconducting cyclotron (to which list might have been added the first pulse stretcher ring, had it been funded sooner). This article will summarize the history of accelerators in Canada, documenting both the successes and the near-misses. Besides the research accelerators, a thriving commercial sector has developed, manufacturing small cyclotrons and linacs, beam line components and superconducting rf cavities.

  2. The Michigan State University Cyclotron Laboratory: Its Early Years

    NASA Astrophysics Data System (ADS)

    Austin, Sam M.

    2016-01-01

    The Michigan State University Cyclotron Laboratory was founded in 1958 and over the years grew in stature, becoming the highest-ranked university-based program in nuclear science. Its K50 cyclotron had unmatched capability as a light-ion accelerator and helped to define what a modern cyclotron could do to advance our understanding of nuclei. This paper describes the first twenty years of the Cyclotron Laboratory's evolution and gives some insight into the cultural characteristics of the laboratory, and of its early members, that led it to thrive.

  3. Control of the Radial Energy Deposition Profile in an Open Magnetic Trap During Electron Cyclotron Plasma Heating

    NASA Astrophysics Data System (ADS)

    Gospodchikov, E. D.; Smolyakova, O. B.

    2016-05-01

    We propose a method for controlling the radial profile of electron cyclotron plasma heating in an axisymmetric magnetic mirror by using minor perturbations of the magnetic field of the mirror. The method is based on the analysis of the ray trajectories behavior near the surface of the electron cyclotron resonance. A way to produce such perturbations by supplementing the system with an additional "quadrupole" pair of magnetic coils is also proposed. The possibility to improve the coupling of radiation with the plasma in an open trap is demonstrated, as well as the possibility to control the energy deposition profile by means of small variations of the current in the additional coils for two basic scenarios of electron cyclotron plasma heating, specifically, longitudinal launching of microwave radiation to the magnetic mirror region and trapping of obliquely launched radiation by the inhomogeneous magnetized-plasma column.

  4. The LBL (Lawrence Berkeley Laboratory) 88-inch cyclotron operating with an ECR source

    SciTech Connect

    Clark, D.J.

    1986-10-01

    The features and operation of the LBL 88-inch Cyclotron are described, including its ECR source, injection system, and the cyclotron center region. The beams that have been accelerated at the cyclotron are discussed. (LEW)

  5. Fundamental ion cyclotron resonance heating of JET deuterium plasmas

    SciTech Connect

    Krasilnikov, A. V.; Van Eester, D.; Biewer, Theodore M; Bonheure, G.; Ericsson, G.; Esposito, Basilio; Giacomelli, L.; Hellesen, C.; Hjalmarsson, A.; Jachmich, S.; Kaschuck, Yu A; Kiptily, V.; Mayoral, M.-L.; Santala, M.; Walden, A.

    2009-03-01

    Radio frequency heating of majority ions is of prime importance for understanding the basic role of auxiliary heating in the activated D T phase of ITER. Majority deuterium ion cyclotron resonance heating (ICRH) experiments at the fundamental cyclotron frequency were performed in JET. In spite of the poor antenna coupling at 25 MHz, this heating scheme proved promising when adopted in combination with D neutral beam injection (NBI). The effect of fundamental ICRH of a D population was clearly demonstrated in these experiments: by adding ~25% of heating power the fusion power was increased up to 30 50%, depending on the type of NBI adopted. At this power level, the ion and electron temperatures increased from Ti ~ 4.0 keV and Te ~ 4.5 keV (NBI-only phase) to Ti ~ 5.5 keV and Te ~ 5.2 keV (ICRH + NBI phase), respectively. The increase in the neutron yield was stronger when 80 keV rather than 130 keV deuterons were injected in the plasma. It is shown that the neutron rate, the diamagnetic energy and the electron as well as the ion temperature scale roughly linearly with the applied RF power. A synergistic effect of the combined use of ICRF and NBI heating was observed: (i) the number of neutron counts measured by the neutron camera during the combined ICRF + NBI phases of the discharges exceeded the sum of the individual counts of the NBI-only and ICRF-only phases; (ii) a substantial increase in the number of slowing-down beam ions was detected by the time of flight neutron spectrometer when ICRF power was switched on; (iii) a small D subpopulation with energies slightly above the NBI launch energy was detected by the neutral particle analyzer and -ray spectroscopy.

  6. Numerical Simulation of a Multi-Cusp Ion Source for High Current H- Cyclotron at RISP

    NASA Astrophysics Data System (ADS)

    Kim, J. H.

    The rare isotope science project (RISP) has been launched in 2011 to support a wide range science program in nuclear, material, and bio-medical sciences as well as interdisciplinary programs. The production of rare isotope beams at RISP is currently configured to include facilities for both an In-flight Fragmentation (IF) system and an Isotope Separator On-Line (ISOL) system, which will utilize a 70 MeV H- cyclotron. The cyclotron will deliver 70 kW proton beam power to ISOL targets, where rare isotopes are generated and re-accelerated by a linear accelerator. A multi-cusp ion source used widely in H- cyclotrons is designed to have cusp geometries of magnetic field inside the ion source chamber, where ions are confined and enhanced plasma densities. Therefore the magnetic confinement fields produced by a number of permanent magnetic poles help to increase H- beam currents. In this work a numerical simulation is performed to understand the effect of multi-cusp magnetic fields when the number of magnetic poles is varied from 6 to 14. It is found that the larger number of magnetic poles provides a stronger ion confinement yielding higher extracted H- ion currents while the extracted electron current becomes lower.

  7. Operational performance of the LBL 88-inch cyclotron with an ECR (Electron Cyclotron Resonance) source

    SciTech Connect

    Lyneis, C.M.

    1986-10-01

    The 88-Inch Cyclotron began regular operation with the ECR (Electron Cyclotron Resonance) source in January 1985. Since then about 80% of the cyclotron operating schedule has been with the ECR source. The light-ion filament source is used only for runs two or more shifts in length using proton, deuteron, /sup 3/He, or alpha beams. Occasionally the polarized ion source is used. The heavy-ion PIG sources are no longer used. The operating experience with the Cyclotron + ECR has been highly successful in terms of reliability, stability, production of high charge state currents, and range of ions which can be produced. The performance of the Cyclotron + ECR has steadily improved since regular operation began. The improvement is a result of better source performance, better stability and tuning of the injection line, and better cyclotron tuning. Development of the ECR source has resulted in improved high charge state performance and a greater variety of ion species. The LBL ECR now produces 14 ..mu..A of O/sup 7 +/, 1 ..mu..A of O/sup 8 +/, 72 ..mu..A of Ar/sup 9 +/, 1.4 ..mu..A of Ar/sup 14 +/, 5 ..mu..A of I/sup 25 +/, and .009 ..mu..A of I/sup 30 +/. Metal ions from Mg, K, and Ca are produced in the ECR using an oven to inject vapor into the plasma chamber. Operation with the oven is quite stable and frequently requires no adjustment during runs lasting several days. Beams of F, Si, S, and Ti have been produced using various compounds as gases or solids with the oven. The overall transmission from source analyzing magnet to cyclotron external beam is typically 2 to 10% with a maximum of 17%. As a result of the improved source performance and transmission a wide variety of new beams can be produced. For example, a 32.5 MeV/u /sup 16/O/sup 8 +/ beam and /sup 48/Ca/sup 11 +/ beams with energy from 200 to 350 MeV have been used for nuclear physics experiments. A 1.08 GeV /sup 36/Ar/sup 18 +/ beam was used to test the response of various scintillator materials to intermediate energy heavy ions.

  8. The surface-state of the topological insulator Bi2Se3 revealed by cyclotron resonance

    SciTech Connect

    Mcdonald, Ross D; Ayala - Valenzuela, Oscar E; Altarawneh, Moaz M; Analytis, James G

    2011-01-14

    Transport measurements of topological insulators are dominated by the conductivity of the bulk, leading to substantial difficulties in resolving the properties of the surface. To this end, we use high magnetic field, rf- and microwave-spectroscopy to selectively couple to the surface conductivity of Bi2Se3 at high frequency. In the frequency range of a few GHz we observe a crossover from quantum oscillations indicative of a small 3D Fermi surface, to cyclotron resonance indicative of a 2D surface state. By probing the conductivity at reduced skin depths, we have observed a 2D cyclotron resonance from a material whose bulk Fermi-surface is 3D. The frequency-magnetic field scaling of this resonance is inconsistent with the bulk effective mass, but more consistent with the dispersion and band filling of a Dirac-like surface state as observed by ARPES, with substantial manybody renormalization.

  9. Electron cyclotron heating in TMX-Upgrade

    SciTech Connect

    Stallard, B.W.; Hooper, E.B. Jr.

    1981-01-01

    TMX-Upgrade, an improved tandem mirror experiment under construction at LLNL, will use electron cyclotron resonance heating (ECRH) to create thermal barriers and to increase the center cell ion confining potential. Gyrotron oscillators (200 kW, 28 GHz) supply the heating power for the potential confined electron (fundamental heating) and the mirror-confined electrons (harmonic heating) in the thermal barriers. Important issues are temperature limitation and microstability for the hot electrons. Off-midplane heating can control anisotropy-driven microstability. Spacially restricting heating offers the possibility of temperature control by limiting the energy for resonant interaction.

  10. C235-V3 cyclotron for a proton therapy center to be installed in the hospital complex of radiation medicine (Dimitrovgrad)

    NASA Astrophysics Data System (ADS)

    Galkin, R. V.; Gurskii, S. V.; Jongen, Y.; Karamysheva, G. A.; Kazarinov, M. Yu.; Korovkin, S. A.; Kostromin, S. A.; Calderan, J.-M.; Cahay, P.; Mokrenko, S. P.; Morozov, N. A.; Nkongolo, H.; Ol'shevskii, A. G.; Paradis, Y.; Petrov, D. S.; Romanov, V. M.; Samsonov, E. V.; Syresin, E. M.; Shakun, A. N.; Shakun, N. G.; Shirkov, G. D.; Shirkov, S. G.

    2014-06-01

    Proton therapy is an effective method of treating oncologic diseases. In Russia, construction of several centers for proton and ion therapy is slated for the years to come. A proton therapy center in Dimitrovgrad will be the first. The Joint Institute for Nuclear Research (Russia) in collaboration with Ion Beam Application (IBA) (Belgium) has designed an C235-V3 medical proton cyclotron for this center. It outperforms previous versions of commercial IBA cyclotrons, which have already been installed in 11 oncologic hospital centers in different countries. Experimental and calculation data for the beam dynamics in the C235-V3 medical cyclotron are presented. Reasons for beam losses during acceleration are considered, the influence of the magnetic field radial component in the midplane of the accelerator and main resonances is studied, and a beam extraction system is designed. In 2011-2012 in Dubna, the cyclotron was mounted, its magnetic field was properly configured, acceleration conditions were optimized, and beam extraction tests were carried out after which it was supplied to Dimitrovgrad. In the C235-V3 cyclotron, an acceleration efficiency of 72% and an extraction efficiency of 62% have been achieved without diaphragming to form a vertical profile of the beam.

  11. Seventeen-millimeter St. Jude Medical Regent valve in patients with small aortic annulus: dose moderate prosthesis-patient mismatch matter?

    PubMed Central

    2014-01-01

    Background The study was designed to evaluate the effects of moderate prosthesis-patient mismatch (defined as 0.65 cm2/m2 < indexed effective orifice area ≤ 0.85 cm2/m2) on midterm outcomes after isolated aortic valve replacement with a 17-mm St. Jude Medical Regent valve in a large series of patients, and to determine if these effects are influenced by patient confounding variables. Methods One-hundred and six patients with and without moderate prosthesis-patient mismatch early after implantation of a 17-mm Regent valve at aortic position were included. Both clinical and echocardiographic assessments were performed preoperatively, at discharge and during follow-up period (mean follow-up time 52.6 ± 11.9 months). Results The prevalence of moderate prosthesis-patient mismatch was documented in 46 patients (43.4%) at discharge. During the follow-up period, no difference in the regression of left ventricular mass, decrease of transvalvular pressure gradients, mortality and prosthesis-related complications was observed between patients with and without moderate prosthesis-patient mismatch. After adjustment for several risk factors, moderate prosthesis-patient mismatch was associated with increased midterm mortality in patients with baseline left ventricular ejection fraction < 50% (HR: 1.80, p = 0.02), but with normal prognosis in those with preserved LV function. Younger age (cut off value = 65 years) was not an independent predictor of increased midterm mortality and valve-related complications in patients with moderate prosthesis-patient mismatch. Conclusions Moderate prosthesis-patient mismatch after aortic valve replacement with a small mechanical prosthesis is associated with increased mortality and adverse events in patients with pre-existing left ventricular dysfunction. Selected patients with small aortic annulus can experience satisfactory clinical improvements and midterm survival after aortic valve replacement with a 17-mm Regent valve. PMID:24438101

  12. Stereotactic Body Radiotherapy Versus Surgery for Medically Operable Stage I Non-Small-Cell Lung Cancer: A Markov Model-Based Decision Analysis

    SciTech Connect

    Louie, Alexander V.; Rodrigues, George; Palma, David A.; Cao, Jeffrey Q.; Yaremko, Brian P.; Malthaner, Richard; Mocanu, Joseph D.

    2011-11-15

    Purpose: To compare the quality-adjusted life expectancy and overall survival in patients with Stage I non-small-cell lung cancer (NSCLC) treated with either stereotactic body radiation therapy (SBRT) or surgery. Methods and Materials: We constructed a Markov model to describe health states after either SBRT or lobectomy for Stage I NSCLC for a 5-year time frame. We report various treatment strategy survival outcomes stratified by age, sex, and pack-year history of smoking, and compared these with an external outcome prediction tool (Adjuvant{exclamation_point} Online). Results: Overall survival, cancer-specific survival, and other causes of death as predicted by our model correlated closely with those predicted by the external prediction tool. Overall survival at 5 years as predicted by baseline analysis of our model is in favor of surgery, with a benefit ranging from 2.2% to 3.0% for all cohorts. Mean quality-adjusted life expectancy ranged from 3.28 to 3.78 years after surgery and from 3.35 to 3.87 years for SBRT. The utility threshold for preferring SBRT over surgery was 0.90. Outcomes were sensitive to quality of life, the proportion of local and regional recurrences treated with standard vs. palliative treatments, and the surgery- and SBRT-related mortalities. Conclusions: The role of SBRT in the medically operable patient is yet to be defined. Our model indicates that SBRT may offer comparable overall survival and quality-adjusted life expectancy as compared with surgical resection. Well-powered prospective studies comparing surgery vs. SBRT in early-stage lung cancer are warranted to further investigate the relative survival, quality of life, and cost characteristics of both treatment paradigms.

  13. Medical History, Lifestyle, Family History, and Occupational Risk Factors for Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma: The InterLymph Non-Hodgkin Lymphoma Subtypes Project

    PubMed Central

    Benavente, Yolanda; Blair, Aaron; Vermeulen, Roel; Cerhan, James R.; Costantini, Adele Seniori; Monnereau, Alain; Nieters, Alexandra; Clavel, Jacqueline; Call, Timothy G.; Maynadié, Marc; Lan, Qing; Clarke, Christina A.; Lightfoot, Tracy; Norman, Aaron D.; Sampson, Joshua N.; Casabonne, Delphine; Cocco, Pierluigi; de Sanjosé, Silvia

    2014-01-01

    Background Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) are two subtypes of non-Hodgkin lymphoma. A number of studies have evaluated associations between risk factors and CLL/SLL risk. However, these associations remain inconsistent or lacked confirmation. This may be due, in part, to the inadequate sample size of CLL/SLL cases. Methods We performed a pooled analysis of 2440 CLL/SLL cases and 15186 controls from 13 case-control studies from Europe, North America, and Australia. We evaluated associations of medical history, family history, lifestyle, and occupational risk factors with CLL/SLL risk. Multivariate logistic regression analyses were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results We confirmed prior inverse associations with any atopic condition and recreational sun exposure. We also confirmed prior elevated associations with usual adult height, hepatitis C virus seropositivity, living or working on a farm, and family history of any hematological malignancy. Novel associations were identified with hairdresser occupation (OR = 1.77, 95% CI = 1.05 to 2.98) and blood transfusion history (OR = 0.79, 95% CI = 0.66 to 0.94). We also found smoking to have modest protective effect (OR = 0.9, 95% CI = 0.81 to 0.99). All exposures showed evidence of independent effects. Conclusions We have identified or confirmed several independent risk factors for CLL/SLL supporting a role for genetics (through family history), immune function (through allergy and sun), infection (through hepatitis C virus), and height, and other pathways of immune response. Given that CLL/SLL has more than 30 susceptibility loci identified to date, studies evaluating the interaction among genetic and nongenetic factors are warranted. PMID:25174025

  14. The autistic syndrome and endogenous ion cyclotron resonance: state of the art.

    PubMed

    Crescentini, Francesco

    2007-01-01

    The autistic syndrome is a multigenic disease whose expression is different according to the level of involvement of different structures in the central nervous system. The pathogenesis is unknown. No completely effective medical therapy has yet been demonstrated. Accepting the request of the families of eight autistic children in Lomazzo, Milan and Naples, we used ion cyclotron resonance (Seqex therapy) therapeutic support after many other therapies had been already carried out on these patients. After regimens consisting of 20-30 treatments with ICR, improvements were noted in all cases. PMID:18097818

  15. Bio-Nano ECRIS: An electron cyclotron resonance ion source for new materials production

    SciTech Connect

    Uchida, T.; Minezaki, H.; Tanaka, K.; Asaji, T.; Muramatsu, M.; Kitagawa, A.; Kato, Y.; Biri, S.

    2010-02-15

    We developed an electron cyclotron resonance ion source (ECRIS) for new materials production on nanoscale. Our main target is the endohedral fullerenes, which have potential in medical care, biotechnology, and nanotechnology. In particular, iron-encapsulated fullerene can be applied as a contrast material for magnetic resonance imaging or microwave heat therapy. Thus, our new ECRIS is named the Bio-Nano ECRIS. In this article, the recent progress of the development of the Bio-Nano ECRIS is reported: (i) iron ion beam production using induction heating oven and (ii) optimization of singly charged C{sub 60} ion beam production.

  16. 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.

  17. 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.

  18. Cyclotron resonance effects on stochastic acceleration of light ionospheric ions

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    The production of energetic ions with conical pitch angle distributions along the auroral field lines is a subject of considerable current interest. There are several theoretical treatments showing the acceleration (heating) of the ions by ion cyclotron waves. The quasi-linear theory predicts no acceleration when the ions are nonresonant. In the present investigation, it is demonstrated that the cyclotron resonances are not crucial for the transverse acceleration of ions by ion cyclotron waves. It is found that transverse energization of ionospheric ions, such as He(+), He(++), O(++), and O(+), is possible by an Electrostatic Hydrogen Cyclotron (EHC) wave even in the absence of cyclotron resonance. The mechanism of acceleration is the nonresonant stochastic heating. However, when there are resonant ions both the total energy gain and the number of accelerated ions increase with increasing parallel wave number.

  19. Concept and utilization of a regional cyclotron center

    NASA Astrophysics Data System (ADS)

    Emran, Ali M.

    1993-06-01

    Cyclotrons have been proven to be valuable tools associated with development and applications of radioisotopes, radiochemicals and radiopharmaceuticals. Utilization of cyclotrons in biomedical research has increased to cover applications with SPECT and PET as major imaging modalities. The extensive cost of establishing a cyclotron facility has prompted development of more economically feasible sources of radioisotopes such as radioisotope generators. This idea presents the disadvantages of less versatility and production shortage. Therefore, the concept of a regional cyclotron center is being introduced for production of radiotracers to be utilized by users in the area. The Cyclotron Facility at the University of Texas Health Sciences Center at Houston (UTHSC-H) is being developed as a regional center where numerous radioisotopes and radiotracers have been developed and applied to various fields.

  20. Design Studies for an Ultra High Field K80 Cyclotron

    NASA Astrophysics Data System (ADS)

    Schubert, Jeff; Blosser, Henry

    1996-05-01

    We are investigating the use of a wide-bore, 8 T magnet as a component of an ultra high field cyclotron. Such a machine would use the highest magnetic field of any cyclotron, to date. The K80 `Eight Tesla Cyclotron' would have roughly the same magnetic rigidity (Bρ) as the Oak Ridge Isochronous Cyclotron in a package of only one fourth the radius, with a corresponding reduction in cost. This cyclotron could accelerate particles with a charge state Q/A = 1/4 to a final energy of between 5 and 6 MeV/nucleon, the energy range currently being used to study superdeformed, high angular momentum nuclei that result from glancing collisions. Studies thus far have stressed achieving sufficient vertical focusing (ν_z) despite the high magnetic field level. The high field also reduces the space available for central region structures, which complicates early-turn focusing, orbit centering and the design of the spiral inflector.

  1. High current DC negative ion source for cyclotron

    NASA Astrophysics Data System (ADS)

    Etoh, H.; Onai, M.; Aoki, Y.; Mitsubori, H.; Arakawa, Y.; Sakuraba, J.; Kato, T.; Mitsumoto, T.; Hiasa, T.; Yajima, S.; Shibata, T.; Hatayama, A.; Okumura, Y.

    2016-02-01

    A filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In Cs-free operation, continuous H- beam of 10 mA and D- beam of 3.3 mA were obtained stably at an arc-discharge power of 3 kW and 2.4 kW, respectively. In Cs-seeded operation, H- beam current reached 22 mA at a lower arc power of 2.6 kW with less co-extracted electron current. The optimum gas flow rate, which gives the highest H- current, was 15 sccm in the Cs-free operation, while it decreased to 4 sccm in the Cs-seeded operation. The relationship between H- production and the design/operating parameters has been also investigated by a numerical study with KEIO-MARC code, which gives a reasonable explanation to the experimental results of the H- current dependence on the arc power.

  2. Electron Cyclotron Resonance Heating on TEXTOR

    SciTech Connect

    Westerhof, E.; Hoekzema, J.A.; Hogeweij, G.M.D.

    2005-02-15

    TEXTOR is equipped with two gyrotrons at 110 and 140 GHz, respectively. Both share a single power supply and a confocal quasi-optical transmission line. They cannot be operated simultaneously. The 110-GHz gyrotron with limited power and pulse length (300 kW; 200 ms) has been used in a first series of experiments on electron cyclotron resonance heating (ECRH) and electron cyclotron current drive (ECCD) and for collective Thomson scattering (CTS) diagnostics of energetic ions. In the future the 110-GHz gyrotron will be operated exclusively for CTS diagnostics, while for ECRH and ECCD, the newly installed 140-GHz, high-power (800-kW), long-pulse (>3-s) gyrotron is now available. The highlights of first ECRH experiments with the 110-GHz gyrotron are reported. These include observations of internal transport barriers with ECRH on various target plasmas: in the current plateau phase of both ohmic and radiation improved mode (RI-mode) discharges. In addition, sawtooth control by localized ECRH is demonstrated. First results on CTS include the observation of the slowing down of energetic ions and of the redistribution of energetic ions in sawtooth crashes.

  3. Cyclotron Resonances in Electron Cloud Dynamics

    SciTech Connect

    Celata, C M; Furman, M A; Vay, J L; Grote, D P; Ng, J T; Pivi, M F; Wang, L F

    2009-05-05

    A new set of resonances for electron cloud dynamics in the presence of a magnetic field has been found. For short beam bunch lengths and low magnetic fields where l{sub b} << 2{pi}{omega}{sub c}, (l{sub b} = bunch duration, {omega}{sub c} = non-relativistic cyclotron frequency) resonances between the bunch frequency and harmonics of the cyclotron frequency cause an increase in the electron cloud density in narrow ranges of magnetic field near the resonances. For ILC parameters the increase in the density is up to a factor {approx} 3, and the spatial distribution of the electrons is broader near resonances, lacking the well-defined density 'stripes' of multipactoring found for non-resonant cases. Simulations with the 2D computer code POSINST, as well as a single-particle tracking code, were used to elucidate the physics of the dynamics. The resonances are expected to affect the electron cloud dynamics in the fringe fields of conventional lattice magnets and in wigglers, where the magnetic fields are low. Results of the simulations, the reason for the bunch-length dependence, and details of the dynamics will be discussed.

  4. Cyclotron Resonances in Electron Cloud Dynamics

    SciTech Connect

    Celata, C. M.; Furman, Miguel A.; Vay, J.-L.; Ng, J. S.T.; Grote, D. P.; Pivi, M. T. F.; Wang, L. F.

    2009-04-29

    A new set of resonances for electron cloud dynamics in the presence of a magnetic field has been found. For short beam bunch lengths and low magnetic fields where lb<< 2pi c/omega c (with lb = bunch length, omega c = non-relativistic cyclotron frequency) resonances between the bunch frequency and harmonics of the electron cyclotron frequency cause an increase in the electron cloud density in narrow ranges of magnetic field near the resonances. For ILC parameters the increase in the density is up to a factor ~;;3, and the spatial distribution of the electrons is broader near resonances, lacking the well-defined vertical density"stripes" found for non-resonant cases. Simulations with the 2D computer code POSINST, as well as a single-particle tracking code, were used to elucidate the physics of the dynamics. The existence of the resonances has been confirmed in experiments at PEP-II. The resonances are expected to affect the electron cloud dynamics in the fringe fields of conventional lattice magnets and in wigglers, where the magnetic fields are low. Results of the simulations and experimental observations, the reason for the bunch-length dependence, and details of the dynamics are discussed here.

  5. Fundamental and harmonic electron cyclotron maser emission

    NASA Astrophysics Data System (ADS)

    Winglee, R. M.

    1985-10-01

    The plasma conditions and features of the energetic electron distribution in electron cyclotron maser emission for which growth in a particular mode is favored when the ratio of the plasma frequency omega(p) to the electron cyclotron frequency Omega(e) is greater than about 0.3 are determined. It is shown that growth at the fundamental is suppressed as omega(p)/Omega(e) increases and emission at harmonics of Omega(e) dominates. Growth at harmonics of Omega(e) is not restricted to the O and X modes, but can also occur for the Z mode. Whether or not growth in a particular mode dominates depends both on omega(p)/Omega(e) and on the form of the distribution. If the density of the energetic electrons is sufficiently large, the dispersion relations of the O and X modes are modified so that the group velocities of the growing O and X mode waves can be comparable to that of the growing Z mode waves.

  6. Ion cyclotron bands in VLF saucers

    NASA Technical Reports Server (NTRS)

    Maeda, Kaichi; Fung, Shing F.; Calvert, Wynne

    1990-01-01

    In the wideband VLF data obtained by the polar orbiting DE-1 satellite over the polar night ion trough region of the upper ionosphere, conspicuous frequency-band structures are found to occur both in absorption and emission, particularly associating with VLF saucers. The attenuation bands indicate that the ions of atomic hydrogen from the polar ionosphere are accelerated by the ac electric fields of VLF waves oscillating normal to the static magnetic field, analogous to a cyclotron accelerator. The observed frequencies of the cyclotron harmonics suggest that the acceleration is taking place in the layer below the satellite at a geocentric distance of less than about 1.5 earth radii. This example indicates the existence of upward propagating hiss at those altitudes inside the auroral zone. On the other hand, the frequency shifts of the emission bands are attributed to a combination of two different types of Doppler shift, one due to the orbital motion of the satellite and the other due to the upward motion of the medium at the emission source. This indicates the existence of an upward plasma flow at the source, with a velocity of the order of 20 km/s inside the saucer. The amount of this frequency shift decreases with increasing harmonic order, indicating a higher phase velocity for the electrostatic waves of higher harmonic order.

  7. The Evergreen State College Cyclotron Project

    NASA Astrophysics Data System (ADS)

    Dhillon, Amandeep; Lessard, Paul; Small, Chris

    2006-05-01

    We have designed a multipurpose cyclotron device, which may be used to conduct a variety of experiments. We are building our device in stages. Our first stage is a FT-ICR spectrometer, which uses an array of induction coils to monitor orbits in the chamber. We will then take the signal and subject it to the Fourier transform, yielding the cyclotron frequencies of all species orbiting in the chamber. Once we have these frequencies, and amplitudes, we can determine the charge to mass ratio, and relative abundance of our species. This type of spectroscopy can distinguish between species with similar masses. We will then use the radio isotopic dating ladder, which requires higher and higher accuracies, beginning with carbon 14 dating, as a measure of our success. Stage two consists of installing an exit port for the accelerated particle beam. For this we have designed a new extraction method that may better suit our particular application rather than the standard methods. At this stage we will use the signal coming from the induction array to determine the frequency at which we oscillate the potential across the gap. This allows us to synchronize the accelerating voltage and the particles orbit such that we can effectively accelerate particles even when at relativistic speeds.

  8. The Evergreen State College Cyclotron Project

    NASA Astrophysics Data System (ADS)

    Lessard, Paul; Dhillon, Amandeep; Smalls, Christopher

    2006-05-01

    We have designed a multipurpose cyclotron device, which may be used in a range of experiments. We are building our device in stages. Our first stage is a FT-ICR spectrometer, which uses an array of induction coils to monitor orbits in the chamber. Applying Fourier transform to the signal from this array will yield the cyclotron frequencies of all species orbiting in the chamber. From these frequencies, and their corresponding amplitudes, we can determine the charge to mass ratio, and relative abundance of species in our sample. This type of spectroscopy can distinguish between species of extremely similar mass. We will use the radio isotopic dating ladder, which requires higher and higher accuracies, beginning with carbon 14 dating, as a yardstick of our Success. During stage two we will install an exit port for an accelerated particle beam. We have designed a new beam extraction method that may better suit our particular application than the standard methods. At this stage we will use the signal coming from the induction array to determine the frequency at which we switch the potential across the gap. This allows us to synchronize the accelerating voltage and the particles orbit in such a way that we can effectively accelerate particles even when moving at relativistic speeds.

  9. Coherent cyclotron motion beyond Kohn's theorem

    NASA Astrophysics Data System (ADS)

    Maag, T.; Bayer, A.; Baierl, S.; Hohenleutner, M.; Korn, T.; Schüller, C.; Schuh, D.; Bougeard, D.; Lange, C.; Huber, R.; Mootz, M.; Sipe, J. E.; Koch, S. W.; Kira, M.

    2016-02-01

    In solids, the high density of charged particles makes many-body interactions a pervasive principle governing optics and electronics. However, Walter Kohn found in 1961 that the cyclotron resonance of Landau-quantized electrons is independent of the seemingly inescapable Coulomb interaction between electrons. Although this surprising theorem has been exploited in sophisticated quantum phenomena, such as ultrastrong light-matter coupling, superradiance and coherent control, the complete absence of nonlinearities excludes many intriguing possibilities, such as quantum-logic protocols. Here, we use intense terahertz pulses to drive the cyclotron response of a two-dimensional electron gas beyond the protective limits of Kohn's theorem. Anharmonic Landau ladder climbing and distinct terahertz four- and six-wave mixing signatures occur, which our theory links to dynamic Coulomb effects between electrons and the positively charged ion background. This new context for Kohn's theorem unveils previously inaccessible internal degrees of freedom of Landau electrons, opening up new realms of ultrafast quantum control for electrons.

  10. Abortion - medical

    MedlinePlus

    ... womb (uterus). There are different types of medical abortions: Therapeutic medical abortion is done because the woman has ... Therapeutic medical abortion; Elective medical abortion; Induced abortion; Nonsurgical abortion

  11. ICRH of JET and LHD Majority Ions at Their Fundamental Cyclotron Frequency

    SciTech Connect

    Krasilnikov, A. V.; Kaschuck, Yu. A.; Amosov, V. N.; Van Eester, D.; Lerche, E.; Mailloux, J.; Stamp, M.; Jachmich, S.; Leggate, H.; Walden, A.; Mayoral, M.-L.; Santala, M.; Kiptily, V.; Popovichev, S.; Vdovin, V.; Biewer, T.; Crombe, K.; Esposito, B.

    2007-09-28

    Results of the experimental studies of ICRH at the fundamental cyclotron frequency of the majority deuterons in JET plasmas with near-tangential deuteron neutral beam injection (NBI) are presented. 1D, 2D and 3D ICRH modeling indicated that several ITER relevant mechanisms of heating may occur simultaneously in this heating scheme: fundamental ion cyclotron resonance heating of majority and beam D ions, impurity ion heating and electron heating due to Landau damping and TTMP. These mechanisms were studied in JET experiments with a {approx}90% D, 5% H plasma including traces of Be and Ar. Up to 2MW of ICRH power was applied at 25 MHz to NBI heated plasmas. In most of the discharges the toroidal magnetic field strength was 3.3T, but in one it was equal to 3.6T. The E{sub +} component of the electric field governs the ion cyclotron heating of not too fast particles. The Doppler shifted RF absorption of the beam deuterons away from the cold resonance at which E{sub +} is small was exploited to enhance the RF power absorption efficiency. Fundamental ICRH experiments were also carried out in LHD hydrogen plasma with high energy hydrogen NBI. ICRH was performed at 38MHz with injected power <1 MW. The effect of fundamental ICRH was clearly demonstrated in both machines.

  12. Energy confinement in the plasma of the T-10 during electron cyclotron heating

    SciTech Connect

    Alikaev, V.V.; Bagdasarov, A.A.; Vasin, N.L.; Esipchuk, Y.V.; Kislov, A.Y.; Notkin, G.E.; Razumova, K.A.

    1987-01-01

    The energy confinement time and the local values of the electron thermal conductivity have been studied in the T-10 tokamak during electron cyclotron heating. The behavior of these properties as functions of the plasma parameters, the microwave power, and the profile of the microwave power was studied. A gyrotron system was capable of injecting a power P/sub R//sub F/ up to 1 MW with a pulse length approx. =100 ms into the plasma. The relationship between the energy confinement in the plasma during electron cyclotron heating and the profiles of the temperature, T/sub e/(r), the current density, j(r), and the pressure, p(r), was studied. A controllable change in the electron temperature profile T(r) was achieved by displacing the electron cyclotron resonance zone by means of a small change in the toroidal magnetic field near the fundamental value B/sub T/ = 3.0 T. The experimental data are explained under the assumption that there are ''limiting'' profiles in a tokamak, which are determined by the permissible density and pressure gradients.

  13. Power requirements for electron cyclotron current drive and ion cyclotron resonance heating for sawtooth control in ITER

    NASA Astrophysics Data System (ADS)

    Chapman, I. T.; Graves, J. P.; Sauter, O.; Zucca, C.; Asunta, O.; Buttery, R. J.; Coda, S.; Goodman, T.; Igochine, V.; Johnson, T.; Jucker, M.; La Haye, R. J.; Lennholm, M.; Contributors, JET-EFDA

    2013-06-01

    13 MW of electron cyclotron current drive (ECCD) power deposited inside the q = 1 surface is likely to reduce the sawtooth period in ITER baseline scenario below the level empirically predicted to trigger neoclassical tearing modes (NTMs). However, since the ECCD control scheme is solely predicated upon changing the local magnetic shear, it is prudent to plan to use a complementary scheme which directly decreases the potential energy of the kink mode in order to reduce the sawtooth period. In the event that the natural sawtooth period is longer than expected, due to enhanced α particle stabilization for instance, this ancillary sawtooth control can be provided from >10MW of ion cyclotron resonance heating (ICRH) power with a resonance just inside the q = 1 surface. Both ECCD and ICRH control schemes would benefit greatly from active feedback of the deposition with respect to the rational surface. If the q = 1 surface can be maintained closer to the magnetic axis, the efficacy of ECCD and ICRH schemes significantly increases, the negative effect on the fusion gain is reduced, and off-axis negative-ion neutral beam injection (NNBI) can also be considered for sawtooth control. Consequently, schemes to reduce the q = 1 radius are highly desirable, such as early heating to delay the current penetration and, of course, active sawtooth destabilization to mediate small frequent sawteeth and retain a small q = 1 radius. Finally, there remains a residual risk that the ECCD + ICRH control actuators cannot keep the sawtooth period below the threshold for triggering NTMs (since this is derived only from empirical scaling and the control modelling has numerous caveats). If this is the case, a secondary control scheme of sawtooth stabilization via ECCD + ICRH + NNBI, interspersed with deliberate triggering of a crash through auxiliary power reduction and simultaneous pre-emptive NTM control by off-axis ECCD has been considered, permitting long transient periods with high fusion gain. The power requirements for the necessary degree of sawtooth control using either destabilization or stabilization schemes are expected to be within the specification of anticipated ICRH and ECRH heating in ITER, provided the requisite power can be dedicated to sawtooth control.

  14. Electron cyclotron resonance (ECR) ion sources

    SciTech Connect

    Jongen, Y.

    1984-05-01

    Starting with the pioneering work of R. Geller and his group in Grenoble (France), at least 14 ECR sources have been built and tested during the last five years. Most of those sources have been extremely successful, providing intense, stable and reliable beams of highly charged ions for cyclotron injection or atomic physics research. However, some of the operational features of those sources disagreed with commonly accepted theories on ECR source operation. To explain the observed behavior of actual sources, it was found necessary to refine some of the crude ideas we had about ECR sources. Some of those new propositions are explained, and used to make some extrapolations on the possible future developments in ECR sources.

  15. Single-pass ion cyclotron resonance absorption

    SciTech Connect

    Breizman, Boris N.; Arefiev, Alexey V.

    2001-03-01

    The ion response to the rf-field during single-pass ion-cyclotron resonance heating (ICRH) can be essentially nonlinear. This paper presents a self-consistent theory of the rf-wave propagation and ion motion through the resonance. An important ingredient of the problem is the ion flow along the magnetic field. The flow velocity limits the time the ions spend at the resonance, which in turn limits the ion energy gain. A feature that makes the problem nonlinear is that the flow accelerates under the effect of the {nabla}B force and rf-pressure. This acceleration can produce a steep decrease in the plasma density at the resonance, resulting in partial reflection of the incident wave.

  16. Electron Cyclotron Resonances in Electron Cloud Dynamics

    SciTech Connect

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

    2008-06-25

    We report a previously unknown resonance for electron cloud dynamics. The 2D simulation code"POSINST" was used to study the electron cloud buildup at different z positions in the International Linear Collider positron damping ring wiggler. An electron equilibrium density enhancement of up to a factor of 3 was found at magnetic field values for which the bunch frequency is an integral multiple of the electron cyclotron frequency. At low magnetic fields the effects of the resonance are prominent, but when B exceeds ~;;(2 pi mec/(elb)), with lb = bunch length, effects of the resonance disappear. Thus short bunches and low B fields are required for observing the effect. The reason for the B field dependence, an explanation of the dynamics, and the results of the 2D simulations and of a single-particle tracking code used to elucidate details of the dynamics are discussed.

  17. Analytic descriptions of ion cyclotron absorption

    SciTech Connect

    Bers, A.; Francis, G.; Fuchs, V.; Lashmore-Davies, C.N.; Ram, A.K.

    1987-05-01

    Analysis of energy propagation and absorption in ion-cyclotron heating of tokamak plasmas has relied on numerical solutions of fourth (and sixth) order differential equations for slab models of the plasma (poloidal) cross section. Realistic two-dimensional and fully toroidal geometry analyses would become quite unwieldy. It is shown here that the analysis of the slab model can be simplified considerably. A first-order differential equation is shown to describe the transmission coefficient for the fast wave, and it is solved analytically. A second order differential equation is shown to adequately describe both transmission and reflection. Conditions for ion absorption or mode conversion are derived. Including toroidal effects in propagation, conditions for electron absorption on the mode-converted ion-Bernstein waves are also described analytically.

  18. Ion Cyclotron Waves in the Solar Wind

    NASA Astrophysics Data System (ADS)

    Wei, H. Y.; Jian, L. K.; Russell, C. T.; Omidi, N.

    2016-02-01

    The ion cyclotron waves (ICWs) refer to electromagnetic transverse waves with nearly field-aligned propagation, circular polarization, and frequencies near the proton gyro-frequency. This chapter presents the ICW studies observed in the solar wind over a wide range of heliocentric distances, at all solar longitudes, and at locations far from planets or comets. To better understand the wave source region, case studies have been performed on a special group of ICW storm events, in which the left-handed (LH) and right-handed (RH) waves were observed simultaneously in the spacecraft frame. The study in the chapter assumes the waves are generated through one possible mechanism (i.e., the temperature anisotropy instability). The variations of the wave properties with heliocentric distances may also provide information on the possible wave generation sources and the effects of the wave to the solar wind plasma.

  19. Improving cancer treatment with cyclotron produced radionuclides. Progress report

    SciTech Connect

    Larson, S.M.; Finn, R.D.

    1993-11-01

    This report describes our continuing long term goal of promoting nuclear medicine applications by improving the scientific basis for tumor diagnosis, treatment and treatment follow-up based on the use of cyclotron produced radiotracers in oncology. The program includes 3 interactive components: Radiochemistry/Cyclotron; Pharmacology; and Immunology. An essential strategy is as follows: novel radionuclides and radiotracers developed in the Radiochemistry/Cyclotron section will be employed in the Pharmacology and Immunology sections during the next year. The development of novel radionuclides and tracers is of course useful in and of itself, but their utility is greatly enhanced by the interaction with the immunology and pharmacology components of the program.

  20. Ionospheric modification at twice the electron cyclotron frequency.

    PubMed

    Djuth, F T; Pedersen, T R; Gerken, E A; Bernhardt, P A; Selcher, C A; Bristow, W A; Kosch, M J

    2005-04-01

    In 2004, a new transmission band was added to the HAARP high-frequency ionospheric modification facility that encompasses the second electron cyclotron harmonic at altitudes between approximately 220 and 330 km. Initial observations indicate that greatly enhanced airglow occurs whenever the transmission frequency approximately matches the second electron cyclotron harmonic at the height of the upper hybrid resonance. This is the reverse of what happens at higher electron cyclotron harmonics. The measured optical emissions confirm the presence of accelerated electrons in the plasma. PMID:15903924

  1. Superconducting cyclotron and its vacuum system

    NASA Astrophysics Data System (ADS)

    Sur, A.; Bhandari, R. K.

    2008-05-01

    A large superconducting cyclotron is under construction at this Centre and will be used to accelerate heavy ion beams to energy up to 80 MeV/A for light heavy ions and about 10 MeV/A for medium mass heavy ions. The vacuum system for this accelerator has several different aspects. The main acceleration chamber will be evacuated to a level of about 10-7 torr using both turbo molecular pumps and specially designed cryopanels. The surfaces exposed to this 'vacuum' are mostly made of OFE copper. The cryogenic transfer lines, to cool the cryopanels, are of several meters in length and they pass through RF resonators extending below the magnet. The cryostat that will house the superconducting coils has an annular vacuum chamber, which is evacuated to a level of approximately 10-5 torr using a turbo molecular pump. Cryopumping action starts once the coils are cooled to low temperatures. A differential pumping is provided below the RF liner that encloses the pole tip of the main magnet. The space that is pumped in this case contains epoxy-potted trim coils wound around the pole tips. Crucial interlocks are provided between the differential vacuum and the acceleration chamber vacuum to avoid distortion of the RF liner, which is made of thin copper sheets. The other important vacuum system provides thermal insulation for the liquid helium transfer lines. In this paper a brief description of the superconducting cyclotron will be given. Details of various vacuum aspects of the accelerator and the logistics of their operation will be presented. Introduction of some of the improved equipment now available and improved techniques are also discussed.

  2. Global Simulation of Electromagnetic Ion Cyclotron Waves

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.; Gamayunov, K.; Gallagher, D. L.; Kozyra, J. U.

    2007-01-01

    It is well known that the effects of electromagnetic ion cyclotron (EMIC) waves on ring current (RC) ion and radiation belt (RB) electron dynamics strongly depend on such particle/wave characteristics as the phase-space distribution function, frequency, wave-normal angle, wave energy, and the form of wave spectral energy density. The consequence is that accurate modeling of EMIC waves and RC particles requires robust inclusion of the interdependent dynamics of wave growth/damping, wave propagation, and particles. Such a self-consistent model is being progressively developed by Khazanov et al. [2002 - 2007]. This model is based on a system of coupled kinetic equations for the RC and EMIC wave power spectral density along with the ray tracing equations. We will discuss the recent progress in understanding EMIC waves formation mechanisms in the inner magnetosphere. This problem remains unsettled in spite of many years of experimental and theoretical studies. Modern satellite observations by CRRES, Polar and Cluster still do not reveal the whole picture experimentally since they do not stay long enough in the generation region to give a full account of all the spatio-temporal structure of EMIC waves. The complete self-consistent theory taking into account all factors significant for EMIC waves generation remains to be developed. Several mechanisms are discussed with respect to formation of EMIC waves, among them are nonlinear modification of the ionospheric reflection by precipitating energetic protons, modulation of ion-cyclotron instability by long-period (Pc3/4) pulsations, reflection of waves from layers of heavy-ion gyroresonances, and nonlinearities of wave generation process. We show that each of these mechanisms have their attractive features and explains certain part experimental data but any of them, if taken alone, meets some difficulties when compared to observations. We conclude that development of a refined nonlinear theory and further correlated analysis of modern satellite and ground-based data is needed to solve this very intriguing problem.

  3. Global Simulation of Electromagnetic Ion Cyclotron Waves

    NASA Technical Reports Server (NTRS)

    Khazanov, George V.; Gallagher, D. L.; Kozyra, J. U.

    2007-01-01

    It is very well known that the effects of electromagnetic ion cyclotron (EMIC) waves on ring current (RC) ion and radiation belt (RB) electron dynamics strongly depend on such particle/wave characteristics as the phase-space distribution function, frequency, wave-normal angle, wave energy, and the form of wave spectral energy density. The consequence is that accurate modeling of EMIC waves and RC particles requires robust inclusion of the interdependent dynamics of wave growth/damping, wave propagation, and particles. Such a self-consistent model is being progressively developed by Khazanov et al. This model is based on a system of coupled kinetic equations for the RC and EMIC wave power spectral density along with the ray tracing equations. We will discuss the recent progress in understanding EMIC waves formation mechanisms in the inner magnetosphere. This problem remains unsettled in spite of many years of experimental and theoretical studies. Modern satellite observations by CRRES, Polar and Cluster still do not reveal the whole picture experimentally since they do not stay long enough in the generation region to give a full account of all the spatio-temporal structure of EMIC waves. The complete self-consistent theory taking into account all factors significant for EMIC waves generation remains to be developed. Several mechanisms are discussed with respect to formation of EMIC waves, among them are nonlinear modification of the ionospheric reflection by precipitating energetic protons, modulation of ion-cyclotron instability by long-period (Pc3/4) pulsations, reflection of waves from layers of heavy-ion gyroresonances, and nonlinearities of wave generation process. We show that each of these mechanisms have their attractive features and explains certain part experimental data but any of them, if taken alone, meets some difficulties when compared to observations. We conclude that development of a refined nonlinear theory and further correlated analysis of modern satellite and ground-based data is needed to solve this very intriguing problem.

  4. Ion cyclotron transmission spectroscopy in the Tokamak Fusion Test Reactor

    SciTech Connect

    Greene, G.J.

    1993-09-01

    The propagation of waves in the ion cyclotron range of frequencies has been investigated experimentally in the Tokamak Fusion Test Reactor. A small, broadband, radiofrequency (rf) magnetic probe located outside the plasma limiter, at a major radius near that of the plasma center, was excited with a low power, frequency swept source (1--200 MHz). Waves propagating to a distant location were detected with a second, identical probe. The rf transmission spectrum revealed a region of attenuation over a band of frequencies for which the minority fundamental resonance was located between the outer plasma edge and the major radius of the probe location. Distinct, non-overlapping attenuation bands were observed from hydrogen and helium-3 minority species; a distinct tritium band should be observed in future DT experiments. Rapid spectrum acquisition during a helium-3 gas puff experiment showed that the wave attenuation involved the plasma core and was not a surface effect. A model in which the received power varied exponentially with the minority density, averaged over the resonance region, fit the time evolution of the probe signal relatively well. Estimation of a 1-d tunneling parameter from the experimental observations is discussed. Minority concentrations of less than 0.5 % can be resolved with this measurement.

  5. Restoration of accelerator facilities damaged by Great East Japan Earthquake at Cyclotron and Radioisotope Center, Tohoku University.

    PubMed

    Wakui, Takashi; Itoh, Masatoshi; Shimada, Kenzi; Yoshida, Hidetomo P; Shinozuka, Tsutomu; Sakemi, Yasuhiro

    2014-01-01

    The Cyclotron and Radioisotope Center (CYRIC) of Tohoku University is a joint-use institution for education and research in a wide variety of fields ranging from physics to medicine. Accelerator facilities at the CYRIC provide opportunities for implementing a broad research program, including medical research using positron emission tomography (PET), with accelerated ions and radioisotopes. At the Great East Japan Earthquake on March 11, 2011, no human injuries occurred and a smooth evacuation was made in the CYRIC, thanks to the anti-earthquake measures such as the renovation of the cyclotron building in 2009 mainly to provide seismic strengthening, fixation of shelves to prevent the falling of objects, and securement of the width of the evacuation route. The preparation of an emergency response manual was also helpful. However, the accelerator facilities were damaged because of strong shaking that continued for a few minutes. For example, two columns on which a 930 cyclotron was placed were damaged, and thereby the 930 cyclotron was inclined. All the elements of beam transport lines were deviated from the beam axis. Some peripheral devices in a HM12 cyclotron were broken. Two shielding doors fell from the carriage onto the floor and blocked the entrances to the rooms. The repair work on the accelerator facilities was started at the end of July 2011. During the repair work, the joint use of the accelerator facilities was suspended. After the repair work was completed, the joint use was re-started at October 2012, one and a half years after the earthquake. PMID:25030295

  6. A line-of-sight electron cyclotron emission receiver for electron cyclotron resonance heating feedback control of tearing modes

    SciTech Connect

    Oosterbeek, J. W.; Buerger, A.; Westerhof, E.; Baar, M. R. de; Berg, M. A. van den; Bongers, W. A.; Graswinckel, M. F.; Hennen, B. A.; Kruijt, O. G.; Thoen, J.; Heidinger, R.; Korsholm, S. B.; Leipold, F.; Nielsen, S. K.

    2008-09-15

    An electron cyclotron emission (ECE) receiver inside the electron cyclotron resonance heating (ECRH) transmission line has been brought into operation. The ECE is extracted by placing a quartz plate acting as a Fabry-Perot interferometer under an angle inside the electron cyclotron wave (ECW) beam. ECE measurements are obtained during high power ECRH operation. This demonstrates the successful operation of the diagnostic and, in particular, a sufficient suppression of the gyrotron component preventing it from interfering with ECE measurements. When integrated into a feedback system for the control of plasma instabilities this line-of-sight ECE diagnostic removes the need to localize the instabilities in absolute coordinates.

  7. Vacuum Control Systems of the Cyclotrons in VECC, Kolkata

    NASA Astrophysics Data System (ADS)

    Roy, Anindya; Akhtar, Javed; Yadav, R. C.; Bhole, R. B.; Pal, Sarbajit; Sarkar, D.; Bhandari, R. K.

    2012-11-01

    VECC has undertaken the modernization of the K-130 Room Temperature Cyclotron (RTC) (operational since 1978) and commissioning of K-500 Superconducting Cyclotron (SCC) at present. The control system of RTC vacuum system has been upgraded to Programmable Logic Controller (PLC) based automated system from relay based manual system. A distributed PLC based system is under installation for SCC vacuum system. The requirement of high vacuum in both the cyclotrons (1×10-6 mbar for RTC and 5 × 10-8 mbar SCC) imposes the reliable local and remote operation of all vacuum components and instrumentation. The design and development of the vacuum control system of two cyclotrons using the Experimental Physics and Industrial Control System (EPICS) distributed real-time software tools are presented.

  8. Cyclotron radiation by a multi-group method

    SciTech Connect

    Chu, T.C.

    1980-01-01

    A multi-energy group technique is developed to study conditions under which cyclotron radiation emission can shift a Maxwellian electron distribution into a non-Maxwellian; and if the electron distribution is non-Maxwellian, to study the rate of cyclotron radiation emission as compared to that emitted by a Maxwellian having the same mean electron density and energy. The assumptions in this study are: the electrons should be in an isotropic medium and the magnetic field should be uniform. The multi-group technique is coupled into a multi-group Fokker-Planck computer code to study electron behavior under the influence of cyclotron radiation emission in a self-consistent fashion. Several non-Maxwellian distributions were simulated to compare their cyclotron emissions with the corresponding energy and number density equivalent Maxwellian distribtions.

  9. Design Study Of Cyclotron Magnet With Permanent Magnet

    NASA Astrophysics Data System (ADS)

    Kim, Hyun Wook; Chai, Jong Seo

    2011-06-01

    Low energy cyclotrons for Positron emission tomography (PET) have been wanted for the production of radio-isotopes after 2002. In the low energy cyclotron magnet design, increase of magnetic field between the poles is needed to make a smaller size of magnet and decrease power consumption. The Permanent magnet can support this work without additional electric power consumption in the cyclotron. In this paper the study of cyclotron magnet design using permanent magnet is shown and also the comparison between normal magnet and the magnet which is designed with permanent magnet is shown. Maximum energy of proton is 8 MeV and RF frequency is 79.3 MHz. 3D CAD design was done by CATIA P3 V5 R18 [1] and the All field calculations had been performed by OPERA-3D TOSCA [2]. The self-made beam dynamics program OPTICY [3] is used for making isochronous field and other calculations.

  10. Design Study Of Cyclotron Magnet With Permanent Magnet

    SciTech Connect

    Kim, Hyun Wook; Chai, Jong Seo

    2011-06-01

    Low energy cyclotrons for Positron emission tomography (PET) have been wanted for the production of radio-isotopes after 2002. In the low energy cyclotron magnet design, increase of magnetic field between the poles is needed to make a smaller size of magnet and decrease power consumption. The Permanent magnet can support this work without additional electric power consumption in the cyclotron. In this paper the study of cyclotron magnet design using permanent magnet is shown and also the comparison between normal magnet and the magnet which is designed with permanent magnet is shown. Maximum energy of proton is 8 MeV and RF frequency is 79.3 MHz. 3D CAD design was done by CATIA P3 V5 R18 and the All field calculations had been performed by OPERA-3D TOSCA. The self-made beam dynamics program OPTICY is used for making isochronous field and other calculations.

  11. Cyclotrons for clinical and biomedical research with PET

    SciTech Connect

    Wolf, A.P.

    1987-01-01

    The purpose of this commentary is to present some background material on cyclotrons and other particle accelerators particularly with a view toward the considerations behind acquiring and installing such a machine for purely clinical and/or biomedical research use.

  12. Single-electron detection and spectroscopy via relativistic cyclotron radiation

    SciTech Connect

    Asner, David M.; Bradley, Rich; De Viveiros Souza Filho, Luiz A.; Doe, Peter J.; Fernandes, Justin L.; Fertl, M.; Finn, Erin C.; Formaggio, Joseph; Furse, Daniel L.; Jones, Anthony M.; Kofron, Jared N.; LaRoque, Benjamin; Leber, Michelle; MCBride, Lisa; Miller, M. L.; Mohanmurthy, Prajwal T.; Monreal, Ben; Oblath, Noah S.; Robertson, R. G. H.; Rosenberg, Leslie; Rybka, Gray; Rysewyk, Devyn M.; Sternberg, Michael G.; Tedeschi, Jonathan R.; Thummler, Thomas; VanDevender, Brent A.; Woods, N. L.

    2015-04-01

    It has been understood since 1897 that accelerating charges should emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. Here we demonstrate single-electron detection in a novel radiofrequency spectrometer. We observe the cyclotron radiation emitted by individual electrons that are produced with mildly-relativistic energies by a gaseous radioactive source and are magnetically trapped. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work is a proof-of-concept for future neutrino mass experiments using this technique.

  13. 6D Muon Ionization Cooling with an Inverse Cyclotron

    SciTech Connect

    Summers, D. J.; Bracker, S. B.; Cremaldi, L. M.; Godang, R.; Palmer, R. B.

    2006-03-20

    A large admittance sector cyclotron filled with LiH wedges surrounded by helium or hydrogen gas is explored. Muons are cooled as they spiral adiabatically into a central swarm. As momentum approaches zero, the momentum spread also approaches zero. Long bunch trains coalesce. Energy loss is used to inject the muons into the outer rim of the cyclotron. The density of material in the cyclotron decreases adiabatically with radius. The sector cyclotron magnetic fields are transformed into an azimuthally symmetric magnetic bottle in the center. Helium gas is used to inhibit muonium formation by positive muons. Deuterium gas is used to allow captured negative muons to escape via the muon catalyzed fusion process. The presence of ionized gas in the center may automatically neutralize space charge. When a bunch train has coalesced into a central swarm, it is ejected axially with an electric kicker pulse.

  14. Heavy-ion injection from tandems into an isochronous cyclotron

    SciTech Connect

    LeVine, M.J.; Chasman, C.

    1981-01-01

    A design has been realized for the injection of heavy ion beams generated by the BNL 3-stage tandem facility into a proposed isochronous cyclotron. The tandem beams are bunched into +- 1/sup 0/ R.F. phase (less than or equal to 0.5 nsec) in two stages. The beam is then injected into the cyclotron through a valley, past a hill, and into the next valley on to a stripper foil. Only a single steerer is required to make trajectory corrections for the different beams. Two achromats are used to regulate the tandem potential and to provide phase control. A final section of the injection optics provides matching of transverse phase space to the acceptance of the cyclotron. The calculations use realistic tandem emittances and magnetic fields for the cyclotron based on measurements with a model magnet.

  15. Undergraduate Education with the Rutgers 12-Inch Cyclotron

    NASA Astrophysics Data System (ADS)

    Koeth, Timothy W.

    The Rutgers 12-Inch Cyclotron is a research grade accelerator dedicated to undergraduate education. From its inception, it has been intended for instruction and has been designed to demonstrate classic beam physics phenomena and provides students hands on experience with accelerator technology. The cyclotron is easily reconfigured, allowing experiments to be designed and performed within one academic semester. Our cyclotron offers students the opportunity to operate an accelerator and directly observe many fundamental beam physics concepts, including axial and radial betatron motion, destructive resonances, weak and azimuthally varying field (AVF) focusing schemes, RF and DEE voltage effects, diagnostic techniques, and perform low energy nuclear reactions. This paper emphasizes the unique beam physics measurements and beam manipulations capable at the Rutgers 12-Inch Cyclotron.

  16. Ohm's law at strong coupling: S duality and the cyclotron resonance

    SciTech Connect

    Hartnoll, Sean A.; Herzog, Christopher P.

    2007-11-15

    We calculate the electrical and thermal conductivities and the thermoelectric coefficient of a class of strongly interacting 2+1-dimensional conformal field theories with anti-de Sitter space duals. We obtain these transport coefficients as a function of charge density, background magnetic field, temperature, and frequency. We show that the thermal conductivity and thermoelectric coefficient are determined by the electrical conductivity alone. At small frequency, in the hydrodynamic limit, we are able to provide a number of analytic formulas for the electrical conductivity. A dominant feature of the conductivity is the presence of a cyclotron pole. We show how bulk electromagnetic duality acts on the transport coefficients.

  17. PET computer programs for use with the 88-inch cyclotron

    SciTech Connect

    Gough, R.A.; Chlosta, L.

    1981-06-01

    This report describes in detail several offline programs written for the PET computer which provide an efficient data management system to assist with the operation of the 88-Inch Cyclotron. This function includes the capability to predict settings for all cyclotron and beam line parameters for all beams within the present operating domain of the facility. The establishment of a data base for operational records is also described from which various aspects of the operating history can be projected.

  18. Status and development of the Kazakhstan isochronous cyclotron

    NASA Astrophysics Data System (ADS)

    Arzumanov, A.; Batischev, V.; Borissenko, A.; Gorkovets, M.; Koptev, V.; Lyssukhin, S.; Mulgin, S.; Popov, Yu.; Zhdanov, S.

    2001-12-01

    A report is presented on the status of the cyclotron in Almaty at present time. In spite of sharp curtailment of government-funded basic research program the cyclotron still remains as multipurpose accelerator facility and is being used for fundamental research and application in different fields of applied science. During last years some cyclotron systems were upgraded and some were designed anew. The system for on-line precise ion beam energy measurement using time-of-flight method was designed and constructed. Inductive pick-up electrodes are integrated into beam transport channel and are located at the distance of 10 m from each other. Average beam energy determination is performed with the accuracy about 0.1%. This system allows to analyze ion beam parameters in pulse-mode of cyclotron operation with macro duty factor in the range of 2-50. In connection with development of cyclotron based radioisotope production and necessity of irradiation of toxic materials and loose and smelted powders with low heat conductivity circular beam scanning system was designed and installed. Transversal rotating magnetic field is generated by stator of usual electro-motor. The scanner allows to form predictable beam power density distribution on the target surface and obtain rather uniform irradiation fields. Cyclotron based neutron source with Be target for research on radioecology and neutron dosimetry was constructed and is located at one of the external beam transportation channel. Parameters of the system and examples of its application are presented.

  19. Ion heating in the field-reversed configuration by rotating magnetic fields near the ion-cyclotron resonance

    PubMed

    Cohen; Glasser

    2000-12-11

    The trajectories of ions confined in a field-reversed configuration (FRC) equilibrium magnetic geometry and heated with a small-amplitude, odd-parity rotating magnetic field (RMF) have been studied with a Hamiltonian computer code. When the RMF frequency is in the ion-cyclotron range, explosive heating occurs. Higher-energy ions are found to have betatron-type orbits, preferentially localized near the FRC's midplane. These results are relevant to a compact magnetic-fusion-reactor design. PMID:11102199

  20. Electromagnetic cyclotron waves near the proton cyclotron frequency in the solar wind

    NASA Astrophysics Data System (ADS)

    Jian, Lan K.; Boardsen, Scott; Moya, Pablo; Stevens, Michael; Alexander, Robert; Vinas, Adolfo

    2015-04-01

    Strong narrow-band electromagnetic waves around the proton cyclotron frequency (fpc) have been found sporadically in the solar wind from 0.3 to 0.7 AU during MESSENGER spacecraft’s cruise phase. These waves are transverse and circularly polarized, and they propagate in directions quasi-parallel to the magnetic field. The wave power decreases quadratically with heliocentric distance, faster than the trend if assuming the conservation of Poynting flux for wave packets, suggesting there is energy dissipation from the waves, which could contribute to the heating and acceleration of solar wind plasma. Although the wave frequency is a few times of fpc in the spacecraft frame, it is a fraction of fpc in the solar wind plasma frame after removing the Doppler shift effect. In this frequency range, the waves can be left-hand (LH) polarized ion cyclotron waves or right-hand (RH) polarized magnetosonic waves. Because the waves are LH or RH polarized in the spacecraft frame with otherwise nearly identical characteristics, they could be due to Doppler shift of a same type of waves or a mixture of waves with intrinsically different polarizations. Through the assistance of audification, we have studied the long-lasting wave events in 2005 using high-cadence magnetic field data from the Wind mission. Statistically, in contrast with general solar wind, the protons at these waves are distributed closer to the proton instability thresholds, while the alpha particles at these waves are distributed further away from the alpha instability thresholds. For selected events of extensive waves, the ion distribution is analyzed in detail. A mixture of temperature anisotropies for core protons, beam protons, and alpha particles, as well as proton beam drift are often found in such events. We conduct linear wave dispersion analysis using these ion moments to examine whether these waves can be explained by the local generation of kinetic instabilities such as the LH ion cyclotron, the RH firehose, and the RH ion beam instability.

  1. Business models and leadership styles in small medical device and bio-science businesses--examples in a region and their implications.

    PubMed

    Williams, D J; Hourd, P C

    2004-01-01

    This paper reviews the leadership styles and business models found in small technologically based businesses operating in the healthcare sector within one of the UK regions, the East Midlands. The most frequently encountered business model strands were 1) mixed economies: that fund development with service income; cross-sectoral product portfolios; and decoupled business portfolios led by a single entrepreneur and 2) scale sensitive "stay small" models including the avoidance of venture capital; "early exit"; and virtual business strands. There was found to be little correlation between leadership style and business model for the small number of businesses surveyed. The avoidance of venture capital is in direct contrast to adjacent regions. PMID:17271481

  2. Ferrite-guided cyclotron-resonance maser.

    PubMed

    Jerby, Eli; Kesar, A; Aharony, A; Breitmeier, G

    2002-06-01

    The concept of a cyclotron-resonance maser (CRM) with a ferrite loading incorporated in its waveguide is proposed. The CRM interaction occurs between the rotating electron beam and the em wave propagating along a longitudinally magnetized ferrite medium. The ferrite anisotropic permeability resembles the CRM susceptibility in many aspects, and particularly in their similar response to the axial magnetic field (the ferrite susceptibility can be regarded as a passive analog of the active CRM interaction). The ferrite loading slows down the phase velocity of the em wave and thus the axial (Weibel) mechanism of the CRM interaction dominates. The ferrite loading enables also a mechanism of spectral tunability for CRM's. The ferrite loading is proposed, therefore, as a useful ingredient for high-power CRM devices. A linear model of the combined ferrite-guided CRM interaction reveals its useful features. Future schemes may also incorporate ferrite sections functioning as isolators, gyrators, or phase shifters within the CRM device itself for selective suppression of backward waves and spurious oscillations, and for gain and efficiency enhancement. PMID:12188841

  3. Characterization of electron cyclotron resonance hydrogen plasmas

    SciTech Connect

    Outten, C.A. . Dept. of Nuclear Engineering); Barbour, J.C.; Wampler, W.R. )

    1990-01-01

    Electron cyclotron resonance (ECR) plasmas yield low energy and high ion density plasmas. The characteristics downstream of an ECR hydrogen plasma were investigated as a function of microwave power and magnetic field. A fast-injection Langmuir probe and a carbon resistance probe were used to determine plasma potential (V{sub p}), electron density (N{sub e}), electron temperature (T{sub e}), ion energy (T{sub i}), and ion fluence. Langmuir probe results showed that at 17 cm downstream from the ECR chamber the plasma characteristics are approximately constant across the center 7 cm of the plasma for 50 Watts of absorbed power. These results gave V{sub p} = 30 {plus minus} 5 eV, N{sub e} = 1 {times} 10{sup 8} cm{sup {minus}3}, and T{sub e} = 10--13 eV. In good agreement with the Langmuir probe results, carbon resistance probes have shown that T{sub i} {le} 50 eV. Also, based on hydrogen chemical sputtering of carbon, the hydrogen (ion and energetic neutrals) fluence rate was determined to be 1 {times} 10{sup 16}/cm{sup 2}-sec. at a pressure of 1 {times} 10{sup {minus}4} Torr and for 50 Watts of absorbed power. 19 refs.

  4. 30-cm electron cyclotron plasma generator

    NASA Technical Reports Server (NTRS)

    Goede, Hank

    1987-01-01

    Experimental results on the development of a 30-cm-diam electron cyclotron resonance plasma generator are presented. This plasma source utilizes samarium-cobalt magnets and microwave power at a frequency of 4.9 GHz to produce a uniform plasma with densities of up to 3 x 10 to the 11th/cu cm in a continuous fashion. The plasma generator contains no internal structures, and is thus inherently simple in construction and operation and inherently durable. The generator was operated with two different magnetic geometries. One used the rare-earth magnets arranged in an axial line cusp configuration, which directly showed plasma production taking place near the walls of the generator where the electron temperature was highest but with the plasma density peaking in the central low B-field regions. The second configuration had magnets arranged to form azimuthal line cusps with approximately closed electron drift surfaces; this configuration showed an improved electrical efficiency of about 135 eV/ion.

  5. Analytical representation of cyclotron magnetic field

    SciTech Connect

    Lee-Whiting, G.E.; Davies, W.G.

    1994-07-01

    A model has been developed for the rapid but accurate calculation of the static magnetic field in the Chalk River cyclotron. The field is expressed in terms of elementary functions which can be handled efficiently in differential-algebra trajectory integrations. Maxwell`s equations are satisfied exactly. Each of seven subdivisions of the superconducting coils is treated by a moment expansion about a central circle. Each pole is modeled as a uniformly magnetized semi-infinite prism. Monopoles and dipoles at the vertices of the polygonal pole faces correct for departures from the true pole shape. Uniform distributions of dipole strength along the edges of the pole-face polygons correct for the local inappropriateness of the assumption of uniform magnetization. The contributions of the yoke and of other relatively distant parts of the structure to the field in the region of particle acceleration are represented by low-order polynomials. Some of the source parameters are obtained by fitting to the measured values of B{sub z} in the horizontal plane of symmetry.

  6. Fullerenes in electron cyclotron resonance ion sources

    SciTech Connect

    Biri, S.; Fekete, E.; Kitagawa, A.; Muramatsu, M.; Janossy, A.; Palinkas, J.

    2006-03-15

    Fullerene plasmas and beams have been produced in our electron cyclotron resonance ion sources (ECRIS) originally designed for other purposes. The ATOMKI-ECRIS is a traditional ion source with solenoid mirror coils to generate highly charged ions. The variable frequencies NIRS-KEI-1 and NIRS-KEI-2 are ECR ion sources built from permanent magnets and specialized for the production of carbon beams. The paper summarizes the experiments and results obtained by these facilities with fullerenes. Continuous effort has been made to get the highest C{sub 60} beam intensities. Surprisingly, the best result was obtained by moving the C{sub 60} oven deep inside the plasma chamber, very close to the resonance zone. Record intensity singly and doubly charged fullerene beams were obtained (600 and 1600 nA, respectively) at lower C{sub 60} material consumption. Fullerene derivatives were also produced. We mixed fullerenes with other plasmas (N, Fe) with the aim of making new materials. Nitrogen encapsulated fullerenes (mass: 720+14=734) were successfully produced. In the case of iron, two methods (ferrocene, oven) were tested. Molecules with mass of 720+56=776 were detected in the extracted beam spectra.

  7. Cyclotron-based effects on plant gravitropism

    NASA Astrophysics Data System (ADS)

    Kordyum, E.; Sobol, M.; Kalinina, Ia.; Bogatina, N.; Kondrachuk, A.

    Primary roots exhibit positive gravitropism and grow in the direction of the gravitational vector, while shoots respond negatively and grow opposite to the gravitational vector. We first demonstrated that the use of a weak combined magnetic field (CMF), which is comprised of a permanent magnetic field and an alternating magnetic field with the frequency resonance of the cyclotron frequency of calcium ions, can change root gravitropism from a positive direction to negative direction. Two-day-old cress seedlings were gravistimulated in a chamber that was placed into a μ-metal shield where this CMF was created. Using this "new model" of a root gravitropic response, we have studied some of its components including the movement of amyloplasts-statoliths in root cap statocytes and the distribution of Ca 2+ ions in the distal elongation zone during gravistimulation. Unlike results from the control, amyloplasts did not sediment in the distal part of a statocyte, and more Ca 2+ accumulation was observed in the upper side of a gravistimulated root for seedlings treated with the CMF. For plants treated with the CMF, it appears that a root gravitropic reaction occurs by a normal physiological process resulting in root bending although in the opposite direction. These results support the hypothesis that both the amyloplasts in the root cap statocytes and calcium are important signaling components in plant gravitropism.

  8. Modelling of Ion Cyclotron Wall Conditioning plasmas

    NASA Astrophysics Data System (ADS)

    Douai, D.; Wauters, T.; Lyssoivan, A.; Marchuk, O.; Wnderlich, D.; Brmond, S.; Lombard, G.; Mollard, P.; Pegouri, B.; Van Oost, G.

    2011-12-01

    Ion Cyclotron Wall Conditioning (ICWC) is envisioned in ITER to clean the wall from impurities, to control the wall isotopic ratio and the hydrogen recycling in the presence of the toroidal magnetic field. Various experiments and modelling are advancing to consolidate this technique. In this contribution the modeling of ICWC is presented, which can be divided in two parts: plasma description and plasma wall interaction. Firstly a 0D plasma model, based on a set of energy and particle balance equations for Maxwellian Hydrogen and Helium species, is presented. The model takes into account elementary collision processes, coupled RF power, particle confinement, wall recycling, and active gas injection and pumping. The RF plasma production process is based mainly on electron collisional ionization. The dependency of the plasma parameters, the Hydrogen and Helium partial pressures and neutral or ionic fluxes on pressure and RF power are quantitatively in good agreement with those obtained experimentally on TORE SUPRA. Secondly an extension of the 0D model including the description of the wall interaction is presented and compared to TORE SUPRA multi-pulse ICWC discharges.

  9. Effective dose to immuno-PET patients due to metastable impurities in cyclotron produced zirconium-89

    NASA Astrophysics Data System (ADS)

    Alfuraih, Abdulrahman; Alzimami, Khalid; Ma, Andy K.; Alghamdi, Ali; Al Jammaz, Ibrahim

    2014-11-01

    Immuno-PET is a nuclear medicine technique that combines positron emission tommography (PET) with radio-labeled monoclonal antibodies (mAbs) for tumor characterization and therapy. Zirconium-89 (89Zr) is an emerging radionuclide for immuno-PET imaging. Its long half-life (78.4 h) gives ample time for the production, the administering and the patient uptake of the tagged radiopharmaceutical. Furthermore, the nuclides will remain in the tumor cells after the mAbs are catabolized so that time series studies are possible without incurring further administration of radiopharmarceuticals. 89Zr can be produced in medical cyclotrons by bombarding an yttrium-89 (89Y) target with a proton beam through the 89Y(p,n)89Zr reaction. In this study, we estimated the effective dose to the head and neck cancer patients undergoing 89Zr-based immune-PET procedures. The production of 89Zr and the impurities from proton irradiation of the 89Y target in a cyclotron was calculated with the Monte Carlo code MCNPX and the nuclear reaction code TALYS. The cumulated activities of the Zr isotopes were derived from real patient data in literature and the effective doses were estimated using the MIRD specific absorbed fraction formalism. The estimated effective dose from 89Zr is 0.5±0.2 mSv/MBq. The highest organ dose is 1.8±0.2 mSv/MBq in the liver. These values are in agreement with those reported in literature. The effective dose from 89mZr is about 0.2-0.3% of the 89Zr dose in the worst case. Since the ratio of 89mZr to 89Zr depends on the cooling time as well as the irradiation details, contaminant dose estimation is an important aspect in optimizing the cyclotron irradiation geometry, energy and time.

  10. Feasibility study on epithermal neutron field for cyclotron-based boron neutron capture therapy.

    PubMed

    Yonai, Shunsuke; Aoki, Takao; Nakamura, Takashi; Yashima, Hiroshi; Baba, Mamoru; Yokobori, Hitoshi; Tahara, Yoshihisa

    2003-08-01

    To realize the accelerator-based boron neutron capture therapy (BNCT) at the Cyclotron and Radioisotope Center of Tohoku University, the feasibility of a cyclotron-based BNCT was evaluated. This study focuses on optimizing the epithermal neutron field with an energy spectrum and intensity suitable for BNCT for various combinations of neutron-producing reactions and moderator materials. Neutrons emitted at 90 degrees from a thick (stopping-length) Ta target, bombarded by 50 MeV protons of 300 microA beam current, were selected as a neutron source, based on the measurement of angular distributions and neutron energy spectra. As assembly composed of iron, AlF3/Al/6LiF, and lead was chosen as moderators, based on the simulation trials using the MCNPX code. The depth dose distributions in a cylindrical phantom, calculated with the MCNPX code, showed that, within 1 h of therapeutic time, the best moderator assembly, which is 30-cm-thick iron, 39-cm-thick AlF3/Al/6LiF, and 1-cm-thick lead, provides an epithermal neutron flux of 0.7 x 10(9) [n cm(-2) s(-1)]. This results in a tumor dose of 20.9 Gy-eq at a depth of 8 cm in the phantom, which is 6.4 Gy-eq higher than that of the Brookhaven Medical Research Reactor at the equivalent condition of maximum normal tissue tolerance. The beam power of the cyclotron is 15 kW, which is much lower than other accelerator-based BNCT proposals. PMID:12945968

  11. Ion Cyclotron Waves at Titan: Harbingers of Atmospheric Loss

    NASA Astrophysics Data System (ADS)

    Russell, C. T.; Wei, H. Y.; Cowee, M. M.; Neubauer, F.; Dougherty, M. K.

    2014-04-01

    When a flowing magnetized plasma intercepts a neutral atmosphere such as Titan's exosphere, we expect that any atoms or molecules that become ionized by photoionization impact ionization or charge exchange could lead to the acceleration and pick-up of those newly formed ions. This process creates an ion distribution function that often is highly unstable to the production of ion-cyclotron waves. Such waves have been observed in the Earth's polar cusp [1], at the Moon [2], at Mars [3], at Io [4], and at Enceladus [5]. We had expected also to observe these waves at Titan but neither the Voyager Titan passage nor the early Cassini Titan flybys produced ion-cyclotron waves. Modelling studies have suggested that the growth time is long and the waves will not grow until some distance far downstream. However, on two passes by Titan T63 and T98, ion cyclotron waves have been seen with the T98 wave field having been much more pronounced. Figure 1 below shows the transverse and compressional power as dynamic spectra versus time on the T98 inbound pass to Titan. The ion cyclotron waves clearly arise at the expected frequency just below the piston cyclotron frequency. It is remarkable that no such waves are seen outbound at T98.This is in agreement with the initial trajectories of newborn ions which lead away from the dense deeper atmosphere inbound and into the dense deeper atmosphere outbound. On the T63 pass, a short period of waves was seen near the proton and H2+ cyclotron frequencies. We discuss these rare ion cyclotron waves at Titan in the light of hybrid simulations of ion pickup under conditions in Saturn's outer magnetosphere.

  12. Characteristics of the resonant instability of surface electrostatic-ion-cyclotron waves in a semi-bounded warm magnetized dusty plasma

    NASA Astrophysics Data System (ADS)

    Hong, Woo-Pyo; Jung, Young-Dae

    2016-03-01

    The influence of magnetic field and dust rotation on the resonant instability of surface electrostatic-ion-cyclotron wave is kinetically investigated in a semi-bounded warm magnetized dusty plasma. The dispersion relation and the temporal growth rate of the surface electrostatic-ion-cyclotron wave are derived by the specular-reflection boundary condition including the magnetic field and dust rotation effects. It is found that the instability domain decreases with an increase of the rotation frequency of elongated dust grain. It is also found that the dependence of the propagation wave number on the temporal growth rate is more significant for small ion cyclotron frequencies. In addition, it is shown that the scaled growth rate increases with an increase of the strength of magnetic field. The variation of the domain and magnitude of temporal growth rate due to the change of plasma parameters is also discussed.

  13. Medical Practice Makes Perfect

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Cedaron Medical Inc., was founded in 1990 as a result of a NASA SBIR (Small Business Innovative Research) grant from Johnson Space Center to develop a Hand Testing and Exercise Unit for use in space. From that research came Dexter, a comprehensive workstation that creates a paperless environment for medical data management.

  14. Uses of ionizing radiation and medical-care-related problems.

    PubMed

    Smathers, J B

    1988-08-01

    The uses of ionizing radiation in medicine are currently undergoing changes due to at least four major influences: (1) the constantly changing public perception of the hazards of radiation, (2) continuing technical innovation and development in equipment, (3) the imposition of diagnosis-related group funding by government health-care funding agencies, and (4) an increase in the average age of the U.S. population. The combined effect of these influences will probably result in a major increase in biplanar fluoroscopic examinations to support nonsurgical approaches such as percutaneous transluminal coronary angioplasty, percutaneous transluminal neuroembolism, and lithotripsy (the fracturing of kidney stones). As some of these examinations can result in 1.5 h of fluoroscopy, major doses to the patient and to the clinical staff can be expected. In addition, improved diagnostic techniques, such as using positron emission tomography (a combination of biochemistry and positron-emitting isotopes), can be expected to increase the number of small cyclotrons installed in medical centers. Counteracting these increases in radiation exposure is the development of digital radiography, which generally results in a lowering of the dose per diagnostic procedure. In the realm of therapeutic uses, one can expect higher-energy treatment accelerators, more patients being released from the hospital on therapeutic doses of isotopes, and a potential acceptance of neutron therapy as a cancer treatment modality. The latter treatment may take the form of boron capture therapy, 252Cf implant therapy, or external beam therapy using high-energy cyclotrons and the p,Be or the d,Be reaction to create the neutrons. To summarize, the cost of medicine and the fear of cancer may result in an increased use of radiation in the treatment of specific maladies and an increased potential for exposure of the general public to ionizing radiation. In contrast, there is a definite trend toward reducing exposure of the public as a result of general radiographic examinations. PMID:3137187

  15. Biological and medical application of SR from the storage rings of VEPP-3 and ``Siberia-2''. The origin of specific changes of small-angle X-ray diffraction pattern of hair and their correlation with the elemental content

    NASA Astrophysics Data System (ADS)

    Aksirov, A. M.; Gerasimov, V. S.; Kondratyev, V. I.; Korneev, V. N.; Kulipanov, G. N.; Lanina, N. F.; Letyagin, V. P.; Mezentsev, N. A.; Sergienko, P. M.; Tolochko, B. P.; Trounova, V. A.; Vazina, A. A.

    2001-09-01

    X-ray diffraction and fluorescent investigations of human hair were carried out using SR of VEPP-3. The small-angle techniques were used for ecological monitoring and medical diagnostics of pathological states of human organisms with the usage of non-invasive methods for express analysis of biological objects, including human and animal tissues: nails, wool and hair samples. Possibility using of hair fibre diffraction to test for pathological conditions is the subject of this paper. X-ray diffraction data allowed us to suppose the two-component structural model of the hair tissue.

  16. [Unravelling medical leadership].

    PubMed

    Voogt, Judith J; van Rensen, Elizabeth L J; Noordegraaf, Mirko; Schneider, Margriet M E

    2015-01-01

    Medical leadership is a popular topic in the Netherlands, and several interest groups now incorporate medical leadership into postgraduate medical education. However, there is no consensus on what this concept entails. By conducting a discourse analysis, a qualitative method which uses language and text to reveal existing viewpoints, this article reveals three perspectives on medical leadership: administrative leadership, leadership within organisations and leadership within each doctor's daily practice. Text analysis shows that the first two perspectives refer to medical leadership mainly in a defensive manner: by demonstrating medical leadership doctors could 'take the lead' once again; patient care only seems to play a small part in the process. These perspectives are not free of consequences, they will determine how the medical profession is constructed. For this reason, it is argued that there should be more emphasis on the third perspective, in which the quality of care for patients is of primary importance. PMID:26271171

  17. Development of a low-level RF control system for PET cyclotron CYCIAE-14

    NASA Astrophysics Data System (ADS)

    Li, Pengzhan; Yin, Zhiguo; Ji, Bin; Zhang, Tianjue; Zhao, Zhenlu

    2014-01-01

    The project of a 14 MeV PET cyclotron aiming at medical diagnosis and treatment was proposed and started at CIAE in 2010. The low-level RF system is designed to stabilize acceleration voltage and control the resonance of the cavity. Based on the experience of the existing CRM Cyclotron in CIAE, a new start-up sequence is developed and tested. The frequency sweeping is used to activate the RF system. Before the tuner is put into use, a new state called "DDS tuning" is applied to trace the resonance frequency to the designed value. This new option state helps to cover the tuning range, if a large frequency variation occurs because of a thermal cavity deformation. The logic control unit detects the spark, reflection, Pulse/CW state and the frequency of the RF source to perform all kinds of protection and state operations. The test bench and on-line test are carried out to verify the initial design.

  18. The effect of a metallic reflector upon cyclotron radiation.

    NASA Technical Reports Server (NTRS)

    Krajcik, R. A.

    1973-01-01

    A careful study of the effect of a metallic reflector upon cyclotron radiation emanating from a uniform plasma is made in which the angular polarization and frequency dependence of both the cyclotron radiation and the metallic reflector is taken into account. The properties of the metallic reflector then enter in a natural way and share equal status with the properties of the plasma. The radiation coefficient, the ratio of the cyclotron radiation absorbed by the reflector to that generated by the plasma, becomes a function of the electron temperature and the plasma depth to cyclotron radiation (or simply plasma depth). The radiation coefficient is determined for both slab and cylindrical geometries for electron temperatures from 20 to 120 keV and plasma depths from 10 to the 19th to 10 to the 27th MKS. A simple analytic approximation is given for the radiation coefficient for each geometry, and the results are then applied to a low-beta thermonuclear device based on the D-D reaction. For beta of the order of 1 to 2%, and for devices of moderate size, the metallic reflector is incapable of reducing the cyclotron radiation loss below that required for a self-sustained D-D reaction.

  19. Electrostatic electron cyclotron harmonic instability near Ganymede

    NASA Astrophysics Data System (ADS)

    Tripathi, A. K.; Singhal, R. P.; Singh, K. P.; Singh, O. N.

    2014-08-01

    Jupiter's moon—Ganymede—is the largest satellite in our solar system. Galileo spacecraft made six close flybys to explore Ganymede. More information was acquired about particle population, magnetic field and plasma waves during these encounters. In this paper, our aim is to study the generation of electrostatic electron cyclotron harmonic (ECH) emissions in the vicinity of Ganymede using the observed particle data. The calculated ECH wave's growth rates are analyzed in the light of observations of plasma waves along the path of Galileo near Ganymede. Dispersion relation for electrostatic mode is solved to obtain the temporal growth rates. A new electron distribution function, fitted to distribution observed near Ganymede, is used in the calculations. A parametric study is performed to evaluate the effect of loss-cone angle and the ratio of plasma to gyro-frequency on growth rates. It is found that ECH waves growth rates generally decrease as the loss-cone angle is increased. However, the ratio plasma to gyro-frequency has almost no effect on the growth rates. These parameters vary considerably along the Galileo trajectory near Ganymede. This is the first study which relates the occurrence of ECH waves with the particle and magnetic field data in the vicinity of Ganymede. The study of ECH wave growth rate near Ganymede is important for the calculation of pitch angle scattering rates of low-energy electrons and their subsequent precipitation into the thin atmosphere of Ganymede producing ultraviolet emissions. Results of the present study may also be relevant for the upcoming JUNO and JUICE missions to Jupiter.

  20. Cyclotron-based of plant gravisensing

    NASA Astrophysics Data System (ADS)

    Kordyum, E.; Kalinina, Ia.; Bogatina, N.; Kondrachuk, A.

    Roots exhibit positive gravitropism they grow in the direction of a gravitational vector while shoots respond negatively and grow opposite to a gravitational vector We first demonstrated the inversion of roots gravitropism from positive to negative one under gravistimulation in the weak combined magnetic field WCMF consisted of permanent magnetic field PMF with the magnitude of order of 50 mu T and altering magnetic field AMF with the 6 mu T magnitude and a frequency of 32 Hz It was found that the effect of inversion has a resonance nature It means that in the interval of frequencies 1-45 Hz inversion of root gravitropism occurs only at frequency 32 Hz 2-3-day old cress seedlings were gravistimulated in moist chambers which are placed in mu -metal shields Inside mu -metal shields combined magnetic fields have been created The magnitude of magnetic fields was measured by a flux-gate magnetometer Experiments were performed in darkness at temperature 20 pm 1 0 C We measured the divergence angle of a growing root from its horizontal position After 1 h of gravistimulation in the WCMF we observed negative gravitropism of cress roots i e they grow in the opposite direction to a gravitational vector Frequency of 32 Hz for the magnitude of the PMF applied formally corresponds to cyclotron frequency of Ca 2 ions This indicates possible participation of calcium ions in root gravitropism There are many evidences of resonance effects of the WCMF on the biological processes that involve Ca 2 but the nature of

  1. Efficient production of high specific activity 64Cu using a biomedical cyclotron.

    PubMed

    McCarthy, D W; Shefer, R E; Klinkowstein, R E; Bass, L A; Margeneau, W H; Cutler, C S; Anderson, C J; Welch, M J

    1997-01-01

    Copper-64 (T 1/2 = 12.7 h) is an intermediate-lived positron-emitting radionuclide that is a useful radiotracer for positron emission tomography (PET) as well as a promising radiotherapy agent for the treatment for cancer. Currently, copper-64 suitable for biomedical studies is produced in the fast neutron flux trap (irradiation of zinc with fast neutrons) at the Missouri University Research Reactor. Access to the fast neutron flux trap is only possible on a weekly basis, making the availability of this tracer very limited. In order to significantly increase the availability of this intermediate-lived radiotracer, we have investigated and developed a method for the efficient production of high specific activity Cu-64 using a small biomedical cyclotron. It has been suggested that it may be possible to produce Cu-64 on a small biomedical cyclotron utilizing the 64Ni(p,n)64Cu nuclear reaction. We have irradiated both natural nickel and enriched (95% and 98%) Ni-64 plated on gold disks. Nickel has been electroplated successfully at thicknesses of approximately 20-300 mm and bombarded with proton currents of 15-45 microA. A special water-cooled target had been designed to facilitate the irradiations on a biomedical cyclotron up to 60 microA. We have shown that it is possible to separate Cu-64 from Ni-64 and other reaction byproducts rapidly and efficiently by using ion exchange chromatography. Production runs using 19-55 mg of 95% enriched Ni-64 have yielded 150-600 mCi of Cu-64 (2.3-5.0 mCi/microAh) with specific activities of 94-310 mci/microgram Cu. The cyclotron produced Cu-64 had been used to radiolabel PTSM [pyruvaldehyde bis-(N4-methylthiosemicarbazone), used to quantify myocardial, cerebral, renal, and tumor blood flow], MAb 1A3 [monoclonal antibody MAb to colon cancer], and octreotide. A recycling technique for the costly Ni-64 target material has been developed. This technique allows the nickel eluted off the column to be recovered and reused in the electroplating of new targets with an overall efficiency of greater than 90%. PMID:9080473

  2. Observations of compound sawteeth in ion cyclotron resonant heating plasma using ECE imaging on experimental advanced superconducting tokamak

    NASA Astrophysics Data System (ADS)

    Hussain, Azam; Zhao, Zhenling; Xie, Jinlin; Zhu, Ping; Liu, Wandong; Ti, Ang

    2016-04-01

    The spatial and temporal evolutions of compound sawteeth were directly observed using 2D electron cyclotron emission imaging on experimental advanced superconducting tokamak. The compound sawtooth consists of partial and full collapses. After partial collapse, the hot core survives as only a small amount of heat disperses outwards, whereas in the following full collapse a large amount of heat is released and the hot core dissipates. The presence of two q = 1 surfaces was not observed. Instead, the compound sawtooth occurs mainly at the beginning of an ion cyclotron resonant frequency heating pulse and during the L-H transition phase, which may be related to heat transport suppression caused by a decrease in electron heat diffusivity.

  3. Precision phase control for the radio frequency system of K500 superconducting cyclotron at Variable Energy Cyclotron Centre, Kolkata

    SciTech Connect

    Som, Sumit; Ghosh, Surajit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Roy, Suprakash

    2013-11-15

    Variable Energy Cyclotron Centre (VECC) has commissioned K500 Superconducting cyclotron (SCC) based on MSU and Texas A and M university cyclotrons. The radio frequency (RF) system of SCC has been commissioned with the stringent requirement of various RF parameters. The three-phase RF system of Superconducting cyclotron has been developed in the frequency range 9–27 MHz with amplitude and phase stability of 100 ppm and ±0.1°, respectively. The phase control system has the option to change the relative phase difference between any two RF cavities and maintain the phase stability within ±0.1° during round-the-clock cyclotron operation. The said precision phase loop consists of both analogue In-phase/Quadrature modulator to achieve faster response and also Direct Digital Synthesis based phase shifter to achieve wide dynamic range as well. This paper discusses detail insights into the various issues of phase control for the K500 SCC at VECC, Kolkata.

  4. Precision phase control for the radio frequency system of K500 superconducting cyclotron at Variable Energy Cyclotron Centre, Kolkata.

    PubMed

    Som, Sumit; Ghosh, Surajit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Roy, Suprakash

    2013-11-01

    Variable Energy Cyclotron Centre (VECC) has commissioned K500 Superconducting cyclotron (SCC) based on MSU and Texas A&M university cyclotrons. The radio frequency (RF) system of SCC has been commissioned with the stringent requirement of various RF parameters. The three-phase RF system of Superconducting cyclotron has been developed in the frequency range 9-27 MHz with amplitude and phase stability of 100 ppm and ±0.1°, respectively. The phase control system has the option to change the relative phase difference between any two RF cavities and maintain the phase stability within ±0.1° during round-the-clock cyclotron operation. The said precision phase loop consists of both analogue In-phase∕Quadrature modulator to achieve faster response and also Direct Digital Synthesis based phase shifter to achieve wide dynamic range as well. This paper discusses detail insights into the various issues of phase control for the K500 SCC at VECC, Kolkata. PMID:24289392

  5. Cassini observations of ion cyclotron waves and ions anisotropy

    NASA Astrophysics Data System (ADS)

    Crary, F. J.; Dols, V. J.; Cassidy, T. A.; Tokar, R. L.

    2013-12-01

    In Saturn's equatorial, inner magnetosphere, the production of fresh ions in a pick-up distribution generates ion cyclotron waves. These waves are a sensitive indicator of fresh plasma production, but the quantitative relation between wave properties and ionization rates is nontrivial. We present a combined analysis of Cassini MAG and CAPS data, from a variety of equatorial orbits between 2005 and 2012. Using the MAG data, we determine the amplitude and peak frequency of ion cyclotron waves. From the CAPS data we extract the parallel and perpendicular velocity distribution of water group ions. We compare these results with hybrid simulations of the ion cyclotron instability and relate the observed wave amplitudes and ion velocity distributions to the production rate of pickup ions. The resulting relation between wave and plasma properties will allow us to infer ion production rates even at times when no direct ion measurements are available.

  6. The next generation of electron cyclotron emission imaging diagnostics (invited)

    SciTech Connect

    Zhang, P.; Domier, C. W.; Liang, T.; Kong, X.; Tobias, B.; Shen, Z.; Luhmann, N. C. Jr.; Park, H.; Classen, I. G. J.; Pol, M. J. van de; Donne, A. J. H.; Jaspers, R.

    2008-10-15

    A 128 channel two-dimensional electron cyclotron emission imaging system collects time-resolved 16x8 images of T{sub e} profiles and fluctuations on the TEXTOR tokamak. Electron cyclotron emission imaging (ECEI) is undergoing significant changes which promise to revolutionize and extend its capabilities far beyond what has been achieved to date. These include the development of a minilens array configuration with increased sensitivity antennas, a new local oscillator pumping scheme, enhanced electron cyclotron resonance heating shielding, and a highly flexible optical design with vertical zoom capability. Horizontal zoom and spot size (rf bandwidth) capabilities are also being developed with new ECEI electronics. An interface module is under development to remotely control all key features of the new ECEI instrument, many of which can be changed during a plasma discharge for maximum flexibility.

  7. Radiation effects testing at the 88-inch cyclotron at LBNL

    SciTech Connect

    McMahan, Margaret A.; Koga, Rokotura

    2001-10-09

    The effects of ionizing particles on sensitive microelectronics is an important component of the design of systems as diverse as satellites and space probes, detectors for high energy physics experiments and even internet server farms. Understanding the effects of radiation on human cells is an equally important endeavor directed towards future manned missions in space and towards cancer therapy. At the 88-Inch Cyclotron at the Berkeley Laboratory, facilities are available for radiation effects testing (RET) with heavy ions and with protons. The techniques for doing these measurements and the advantages of using a cyclotron will be discussed, and the Cyclotron facilities will be compared with other facilities worldwide. RET of the same part at several facilities of varying beam energy can provide tests of the simple models used in this field and elucidate the relative importance of atomic and nuclear effects. The results and implications of such measurements will be discussed.

  8. A 1D Model For Describing Ion Cyclotron Resonance Heating At Arbitrary Cyclotron Harmonics

    NASA Astrophysics Data System (ADS)

    Van Eester, Dirk; Lerche, Ernesto

    2011-12-01

    Both at low and higher cyclotron harmonics, properly accounting for finite Larmor radius effects is crucial in many ICRF heating scenario's creating high energy tails. The present paper discusses an extension of the 1D TOMCAT wave equation solver [1] to arbitrary harmonics and arbitrary wavelengths. Rather than adopting the particle position, the guiding center position is used as the independent variable when writing down an expression for the dielectric response that is suitable for numerical application. This choice of variable yields symmetric and intuitive expressions, and guarantees that a positive definite power absorption is obtained for any of the wave modes in the plasma. Rather than relying on a truncated Taylor series expansion of the dielectric response, an integro-differential approach is proposed. To keep the required computation time for this generalized description reasonable tabulation of integrals is intensively used. An example is provided to illustrate the potential of the new wave code.

  9. Detection of small trace molecules in human and animal exhalation by tunable diode lasers for applications in biochemistry and medical diagnostics

    NASA Astrophysics Data System (ADS)

    Stepanov, Eugene V.; Kouznetsov, Andrian I.; Zyrianov, Pavel V.; Skrupskii, Vladimir A.; Shulagin, Yurii A.; Galagan, Marina E.

    1995-02-01

    Tunable diode laser spectroscopy (TDLS) is proposed for content measurements of trace gases like CO, CO2, NH3, CH4, NO, NO2 in human and animal exhalation. High sensitivity and wide dynamic range of the method ensure fast detection of these gases at ppb level and within the accuracy better than 10%. One-expiration sample is enough to reach these parameters. There is no need for any preliminary preparations of tested samples. Some pairs of the gases, for instance, CO and CO2, NH3 and CO2 and CO and N2O, can be measured simultaneously by one laser providing complex studies. The high sensitive gas analysis could provide necessary background to the noninvasive diagnostics in a wide variety of medical problems. Perspectives of the TDLS methods in application to medicine diagnostics are demonstrated by the first results of exhalation tests.

  10. Effect of high energy electrons on H- production and destruction in a high current DC negative ion source for cyclotron

    NASA Astrophysics Data System (ADS)

    Onai, M.; Etoh, H.; Aoki, Y.; Shibata, T.; Mattei, S.; Fujita, S.; Hatayama, A.; Lettry, J.

    2016-02-01

    Recently, a filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In this study, numerical modeling of the filament arc-discharge source plasma has been done with kinetic modeling of electrons in the ion source plasmas by the multi-cusp arc-discharge code and zero dimensional rate equations for hydrogen molecules and negative ions. In this paper, main focus is placed on the effects of the arc-discharge power on the electron energy distribution function and the resultant H- production. The modelling results reasonably explains the dependence of the H- extraction current on the arc-discharge power in the experiments.

  11. Electron cyclotron resonance charge breeder ion source simulation by MCBC and GEM

    SciTech Connect

    Kim, J. S.; Zhao, L.; Cluggish, B. P.; Bogatu, I. N.; Pardo, R.

    2008-02-15

    Numerical simulation results by the GEM and MCBC codes are presented, along with a comparison with experiments for beam capture dynamics and parameter studies of charge state distribution (CSD) of electron cyclotron resonance charge breeder ion sources. First, steady state plasma profiles are presented by GEM with respect to key experimental parameters such as rf power and gas pressure. As rf power increases, electron density increases by a small amount and electron energy by a large amount. The central electrostatic potential dip also increased. Next, MCBC is used to trace injected beam ions to obtain beam capture profiles. Using the captured ion profiles, GEM obtains a CSD of beam ions. As backscattering can be significant, capturing the ions near the center of the device enhances the CSD. The effect of rf power on the beam CSD is mainly due to different steady states plasmas. Example cases are presented assuming that the beam ions are small enough not to affect the plasma.

  12. Electron cyclotron heating experiments on the DIII-D tokamak

    SciTech Connect

    Prater, R.; Austin, M.E.; Bernabei, S.

    1998-01-01

    Initial experiments on heating and current drive using second harmonic electron cyclotron heating (ECH) are being performed on the DIII-D tokamak using the new 110 GHz ECH system. Modulation of the ECH power in the frequency range 50 to 300 Hz and detection of the temperature perturbation by ECE diagnostics is used to validate the location of the heating. This technique also determines an upper bound on the width of the deposition profile. Analysis of electron cyclotron current drive indicates that up to 0.17 MA of central current is driven, resulting in a negative loop voltage near the axis.

  13. Magnetosphere cyclotron maser: Backward wave oscillator generation regime

    SciTech Connect

    Trakhtengerts, V.Y.

    1995-09-01

    A new generation regime of the magnetosphere cyclotron maser is considered, based on phase coherence effects in wave-particle systems with step-like deformations of electron velocity distribution functions. Such deformations appear during cyclotron interactions of noise-like whistler wave emissions and energetic electrons at the boundaries between resonant and nonresonant particles. The new regime is similar to the backward wave oscillator in laboratory electronic devices. This regime applies to the generation of chorus emissions and may explain the connection between chorus and hiss, their fast growth rates, and the temporal succession of chorus elements. 30 refs., 1 fig.

  14. Improved tuning and matching of ion cyclotron systems

    SciTech Connect

    Swain, D.W.; Goulding, R.H.; Baity, F.W.; Hoffman, D.J.; Pinsker, R.I.; deGrassie, J.S.; Petty, C.C.

    1996-09-01

    Future fusion devices will require delivery of ion cyclotron heating and current drive power during plasma changes (e.g., L-H transition, ELMs). The use of a passive circuit (``ELM dump``) to protect the RF sources during transients has been demonstrated on DIII-D, and the results are applied to the ITER ion cyclotron system in this analysis. In addition, the use of frequency shifting to compensate for plasma load changes is illustrated for a possible ITER tuning and matching system.

  15. 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.

  16. ELECTRON CYCLOTRON CURRENT DRIVE EFFICIENCY IN GENERAL TOKAMAK GEOMETRY

    SciTech Connect

    LIN-LUI,Y.R; CHAN,V.S; PRATER,R

    2003-03-01

    Green's-function techniques are used to calculate electron cyclotron current drive (ECCD) efficiency in general tokamak geometry in the low-collisionality regime. Fully relativistic electron dynamics is employed in the theoretical formulation. The high-velocity collision model is used to model Coulomb collisions and a simplified quasi-linear rf diffusion operator describes wave-particle interactions. The approximate analytic solutions which are benchmarked with a widely used ECCD model, facilitate time-dependent simulations of tokamak operational scenarios using the non-inductive current drive of electron cyclotron waves.

  17. Microcomputer based control system for the TAMU K-500 cyclotron

    NASA Astrophysics Data System (ADS)

    Haenni, D. R.

    1987-04-01

    A parallel processor control system is being implemented for the K-500 superconducting cyclotron at TAMU. It consists of 10 cost effective personal computers communicating via a local area network. The cyclotron hardware is interfaced to the control system through IEEE-696 (STD bus) I/O cards and a memory mapped, tristate parallel data bus. Most of the software is being written in FORTH. Specific programs for each processor are compiled using tabular information extracted from a database describing the controls and accelerator hardware interfaces. This approach provides considerable flexibility in adapting the software to changing hardware configurations while eliminating the usual computational bottlenecks associated with an on-line data base.

  18. Phase-sensitive cyclotron frequency measurements at ultralow energies.

    PubMed

    Sturm, Sven; Wagner, Anke; Schabinger, Birgit; Blaum, Klaus

    2011-09-30

    A novel technique for a direct and coherent measurement of the modified cyclotron frequency of an ion in a Penning trap at energies close to the thermal cooling limit is presented. This allows a rapid and both precise and accurate determination of the free-space cyclotron frequency in real Penning traps despite the existence of electric and magnetic field imperfections and relativistic shifts. The demonstrated performance paves the way for considerably improved bound-state g-factor measurements on the 10ppt level and mass measurements in the 1ppt range and possibly below. PMID:22107189

  19. Backward wave cyclotron-maser emission in the auroral magnetosphere.

    PubMed

    Speirs, D C; Bingham, R; Cairns, R A; Vorgul, I; Kellett, B J; Phelps, A D R; Ronald, K

    2014-10-10

    In this Letter, we present theory and particle-in-cell simulations describing cyclotron radio emission from Earth's auroral region and similar phenomena in other astrophysical environments. In particular, we find that the radiation, generated by a down-going electron horseshoe distribution is due to a backward-wave cyclotron-maser emission process. The backward wave nature of the radiation contributes to upward refraction of the radiation that is also enhanced by a density inhomogeneity. We also show that the radiation is preferentially amplified along the auroral oval rather than transversely. The results are in agreement with recent Cluster observations. PMID:25375713

  20. N-bursty emission from Uranus: A cyclotron maser source?

    NASA Technical Reports Server (NTRS)

    Curran, D. B.; Menietti, J. D.

    1993-01-01

    Ray tracing studies of RX-mode emission from the north polar regions of Uranus indicate that the n-bursty radio emission may have a source along field lines with footprints near the northern magnetic pole (perhaps in the cusp), but not necessarily associated with regions of strong UV emission. This is in contrast with similar studies for the Uranus nightside smooth radio emission, which are believed to be due to the cyclotron maser instability. Source regions can be found for both hollow and filled emission cones and for frequencies well above the local gyrofreuquency implying that mechanisms other than the cyclotron maser mechanism may be operating.

  1. Fluid equations in the presence of electron cyclotron current drive

    NASA Astrophysics Data System (ADS)

    Jenkins, Thomas G.; Kruger, Scott E.

    2012-12-01

    Two-fluid equations, which include the physics imparted by an externally applied radiofrequency source near electron cyclotron resonance, are derived in their extended magnetohydrodynamic forms using the formalism of Hegna and Callen [Phys. Plasmas 16, 112501 (2009)]. The equations are compatible with the closed fluid/drift-kinetic model developed by Ramos [Phys. Plasmas 17, 082502 (2010); 18, 102506 (2011)] for fusion-relevant regimes with low collisionality and slow dynamics, and they facilitate the development of advanced computational models for electron cyclotron current drive-induced suppression of neoclassical tearing modes.

  2. Single-Electron Detection and Spectroscopy via Relativistic Cyclotron Radiation.

    PubMed

    Asner, D M; Bradley, R F; de Viveiros, L; Doe, P J; Fernandes, J L; Fertl, M; Finn, E C; Formaggio, J A; Furse, D; Jones, A M; Kofron, J N; LaRoque, B H; Leber, M; McBride, E L; Miller, M L; Mohanmurthy, P; Monreal, B; Oblath, N S; Robertson, R G H; Rosenberg, L J; Rybka, G; Rysewyk, D; Sternberg, M G; Tedeschi, J R; Thümmler, T; VanDevender, B A; Woods, N L

    2015-04-24

    It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Although first derived in 1904, cyclotron radiation from a single electron orbiting in a magnetic field has never been observed directly. We demonstrate single-electron detection in a novel radio-frequency spectrometer. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta electron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay end point, and this work demonstrates a fundamentally new approach to precision beta spectroscopy for future neutrino mass experiments. PMID:25955048

  3. Vacuum measurements of the K500 cyclotron accelerator chamber

    SciTech Connect

    Mallory, M.L.; Miller, P.S.; Kuchar, J.; Hudson, E.D.

    1986-01-01

    To evaluate the effectiveness of the unique internal cryopumping system, the pressure in the K500 superconducting cyclotron was measured as a function of radius for various gas flow rates emanating from the internal PIG source. For the test, a nude ion gauge with vertical dimension less than 2.3 cm was built and mounted on the internal beam probe. The effect of magnetic field on the ion gauge reading was determined and a method of degaussing the cyclotron was devised. Data from the normal shielded ion gauge located approximately 6 m away from the median plane was correlated with the internal vacuum measurements.

  4. Analysis of gamma-ray burst spectra with cyclotron lines

    NASA Technical Reports Server (NTRS)

    Kargatis, Vincent; Liang, Edison P.

    1992-01-01

    Motivated by the recent developments in the cyclotron resonance upscattering of soft photons or CUSP model of Gamma Ray Burst (GBR) continuum spectra, we revisit a select database of GRBs with credible cyclotron absorption features. We measure the break energy of the continuum, the slope below the break and deduce the soft photon energy or the electron beam Lorentz factor cutoff. We study the correlation (or lack of) between various parameters in the context of the CUSP model. One surprise result is that there appears to be marginal correlation between the break energy and the spectral index below the break.

  5. Temperature-resonant cyclotron spectra in confined geometries.

    PubMed

    Pototsky, A; Hänggi, P; Marchesoni, F; Savel'ev, S

    2011-07-01

    We consider a two-dimensional gas of colliding charged particles confined to finite size containers of various geometries and subjected to a uniform orthogonal magnetic field. The gas spectral densities are characterized by a broad peak at the cyclotron frequency. Unlike for infinitely extended gases, where the amplitude of the cyclotron peak grows linearly with temperature, here confinement causes such a peak to go through a maximum for an optimal temperature. In view of the fluctuation-dissipation theorem, the reported resonance effect has a direct counterpart in the electric susceptibility of the confined magnetized gas. PMID:21867113

  6. Progress in the development of an H- ion source for cyclotrons

    NASA Astrophysics Data System (ADS)

    Etoh, H.; Aoki, Y.; Mitsubori, H.; Arakawa, Y.; Kato, T.; Sakuraba, J.; Mitsumoto, T.; Yajima, S.; Okumura, Y.

    2015-04-01

    A multi-cusp DC H- ion source has been developed for cyclotrons in medical use. Beam optics of the H- ion beam is studied using a 2D beam trajectory code. The simulation results are compared with the experimental results obtained in the Mark I source, which has produced up to 16 mA H- ion beams. The optimum extraction voltages show good agreement between the calculation and the experimental results. A new ion source, Mark II source, is designed to achieve the next goal of producing an H- beam of 20 mA. The magnetic field configurations and the plasma electrode design are optimized for Cs-seeded operation. Primary electron trajectory simulation shows that primary electrons are confined well and the magnetic filter prevents the primary electrons from entering into the extraction region.

  7. Development of Electron Cyclotron Resonance Ion Source for Synthesis of Endohedral Metallofullerenes

    SciTech Connect

    Tanaka, K.; Muramatsu, M.; Uchida, T.; Hanajiri, T.; Yoshida, Y.; Biri, S.; Kitagawa, A.; Kato, Y.

    2008-11-03

    A new electron cyclotron resonance ion source (ECRIS) has been constructed for synthesis of endohedral metallofullerenes. The main purpose of the ion source is to produce new biological and medical materials. The design is based on ECRIS for production of multicharged ion beams with a traditional minimum-B magnetic field. An 8-10 GHz traveling wave tube (TWT) amplifier and a 2.45 GHz magnetron have been applied as microwave sources. Fullerene and metal vapor are introduced with a filament heating micro-oven and an induction heating oven, respectively. In preliminary ion-extraction test, Ar{sup +} is 54 {mu}A. Many broken fullerenes such as C{sub 58} and C{sub 56} are observed in fullerene ion beams.

  8. Investigations of proton beam energy of the MC-50 cyclotron at KIRAMS

    NASA Astrophysics Data System (ADS)

    Khandaker, Mayeen Uddin; Kim, Guinyun; Kim, Kwangsoo; Bin Abu Kassim, Hasan; Nikouravan, Bijan

    2011-07-01

    The accuracy of the measured excitation functions of nuclear reactions largely depend on the precise measurements of the exposed beam energy in activation experiment. We investigated the proton beam energy of the MC-50 cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS) employing the method natCu(p,xn)62Zn / natCu(p,xn)65Zn together with a stacked-foil activation technique. The beam energy along with the stacked samples was also theoretically calculated using computer program SRIM-2003. The measured beam energy showed generally a good agreement with the calculated ones, and this fact demonstrated that the energy (<30 MeV) of the proton beam could be determined by irradiating thin metallic Cu foil target with natural isotopic compositions. Hence, this may be considered as a useful technique for beam monitoring purposes in activation experiment.

  9. Progress in the development of an H{sup −} ion source for cyclotrons

    SciTech Connect

    Etoh, H. Aoki, Y.; Mitsubori, H.; Arakawa, Y.; Kato, T.; Sakuraba, J.; Mitsumoto, T.; Yajima, S.; Okumura, Y.

    2015-04-08

    A multi-cusp DC H{sup −} ion source has been developed for cyclotrons in medical use. Beam optics of the H{sup −} ion beam is studied using a 2D beam trajectory code. The simulation results are compared with the experimental results obtained in the Mark I source, which has produced up to 16 mA H{sup −} ion beams. The optimum extraction voltages show good agreement between the calculation and the experimental results. A new ion source, Mark II source, is designed to achieve the next goal of producing an H{sup −} beam of 20 mA. The magnetic field configurations and the plasma electrode design are optimized for Cs-seeded operation. Primary electron trajectory simulation shows that primary electrons are confined well and the magnetic filter prevents the primary electrons from entering into the extraction region.

  10. Medical marijuana

    MedlinePlus

    ... Possession of marijuana is illegal under federal law. Medical marijuana refers to using marijuana to treat certain medical ... Medical marijuana may be: Smoked Vaporized Eaten Taken as a liquid extract Marijuana leaves and buds contain substances ...

  11. Medical telesensors

    NASA Astrophysics Data System (ADS)

    Ferrell, Trinidad L.; Crilly, P. B.; Smith, S. F.; Wintenberg, Alan L.; Britton, Charles L., Jr.; Morrison, Gilbert W.; Ericson, M. N.; Hedden, D.; Bouldin, Donald W.; Passian, A.; Downey, Todd R.; Wig, A. G.; Meriaudeau, Fabrice

    1998-05-01

    Medical telesensors are self-contained integrated circuits for measuring and transmitting vital signs over a distance of approximately 1-2 meters. The circuits are unhoused and contain a sensor, signal processing and modulation electronics, a spread-spectrum transmitter, an antenna and a thin-film battery. We report on a body-temperature telesensor, which is sufficiently small to be placed on a tympanic membrane in a child's ear. We also report on a pulse-oximeter telesensor and a micropack receiver/long- range transmitter unit, which receives form a telesensor array and analyzes and re-transmits the vital signs over a longer range. Signal analytics are presented for the pulse oximeter, which is currently in the form of a finger ring. A multichip module is presented as the basic signal-analysis component. The module contains a microprocessor, a field=programmable gate array, memory elements and other components necessary for determining trauma and reporting signals.

  12. Laboratory and cyclotron requirements for PET research

    SciTech Connect

    Schlyer, D.J.

    1993-06-01

    This report describes four types of PET facilities: Clinical PET with no radionuclide production; clinical PET with a small accelerator; clinical PET with research support; and research PET facilities. General facility considerations are also discussed.

  13. 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.

  14. Development of a miniature microwave electron cyclotron resonance plasma ion thruster for exospheric micro-propulsion

    NASA Astrophysics Data System (ADS)

    Dey, Indranuj; Toyoda, Yuji; Yamamoto, Naoji; Nakashima, Hideki

    2015-12-01

    A miniature microwave electron cyclotron resonance plasma source [(discharge diameter)/(microwave cutoff diameter) < 0.3] has been developed at Kyushu University to be used as an ion thruster in micro-propulsion applications in the exosphere. The discharge source uses both radial and axial magnetostatic field confinement to facilitate electron cyclotron resonance and increase the electron dwell time in the volume, thereby enhancing plasma production efficiency. Performance of the ion thruster is studied at 3 microwave frequencies (1.2 GHz, 1.6 GHz, and 2.45 GHz), for low input powers (<15 W) and small xenon mass flow rates (<40 μg/s), by experimentally measuring the extracted ion beam current through a potential difference of ≅1200 V. The discharge geometry is found to operate most efficiently at an input microwave frequency of 1.6 GHz. At this frequency, for an input power of 8 W, and propellant (xenon) mass flow rate of 21 μg/s, 13.7 mA of ion beam current is obtained, equivalent to an calculated thrust of 0.74 mN.

  15. A 70-GHz Electron Cyclotron Resonance Heating System for Heliotron J

    SciTech Connect

    Shidara, Hiroyuki; Nagasaki, Kazunobu; Sakamoto, Kinzo

    2004-01-15

    A 70-GHz electron cyclotron resonance heating (ECRH) system has been constructed in a helical-axis heliotron device, Heliotron J, in order to realize localized heating and current drive experiments. Since the Heliotron J plasma has a three-dimensional complex shape, the ECRH system is designed to satisfy the requirement of wide steering capability in both the toroidal and poloidal directions. The low-power transmission test shows that the beam radius of the focused Gaussian beam is 22 mm at the magnetic axis, which is small enough compared to the averaged minor plasma radius (170 mm), and the launching system covers a wide toroidal steering range from perpendicular to tangential injection by replacing the steering plane mirror. Since these characteristics satisfy the condition for controlling the power localization in the three-dimensional helical-axis configuration, it is possible to explore the on- and off-axis heating over most of the plasma radius (0 < r/a < 0.7) and the electron cyclotron current drive. In the high-power transmission test, the transmission efficiency of the 20-m corrugated waveguide is 92%, and the available output power to the vacuum vessel is up to 0.4 MW. Plasma production and heating are successfully performed using this ECRH system.

  16. Development of microwave ion source and low energy beam transport system for high current cyclotron

    NASA Astrophysics Data System (ADS)

    Pandit, V. S.; Sing Babu, P.; Goswami, A.; Srivastava, S.; Misra, A.; Chatterjee, Mou; Nabhiraj, P. Y.; Yadav, R. C.; Bhattacharya, S.; Roy, S.; Nandi, C.; Pal, G.; Thakur, S. K.

    2013-12-01

    A 2.45 GHz microwave ion source and a low energy beam transport system have been developed to study the high intensity proton beam injection into a 10 MeV, 5 mA compact cyclotron. We have extracted proton beam more than 10 mA at 80 kV as measured by the DCCT after the extraction and a well collimated beam of 7 mA (through 1 cm × 1 cm slit) at the faraday cup 1.5 m away from the source. The transport of protons from the ion source in the presence of H2+, H3+ species has been studied using PIC simulations through our transport line which consists of two solenoids. We have also installed a small dipole magnet with similar field as that of the cyclotron along with vacuum chamber, spiral inflector and few diagnostic elements at the end of the beam line. In the preliminary testing of inflection, we achieved 1 mA beam on the faraday cup at the exit of inflector with ∼60% transmission efficiency.

  17. Properties Of Waves At The Proton Cyclotron Frequency Upstream From Mars

    NASA Astrophysics Data System (ADS)

    Romanelli, N.; Bertucci, C.; Gomez, D. O.; Mazelle, C. X.

    2012-12-01

    We present a study on the properties of electromagnetic plasma waves in the region upstream of the Martian bow shock, detected by the magnetometer and electron reflectometer (MAG / ER) onboard the Mars Global Surveyor (MGS) spacecraft during the period known as Science Phasing Orbits (SPO). The waves found display frequencies in the reference system of MGS (SC) which are close to the local proton cyclotron frequency. Minimum variance analysis (MVA) shows that these 'proton cyclotron frequency' waves (PCWs) are characterized - in the SC frame - by a left-hand, elliptical polarization and propagate almost parallel to the background magnetic field. They also have a small degree of compressibility and an amplitude that decreases with radial distance from the planet. The latter result supports the idea that the source of these waves is Mars. In order to determine the instability which could produce the observed waves, we studied the relation between their polarization and the direction of the mean magnetic field relative to the solar wind velocity direction. In addition, we find that these waves are not associated with the foreshock and that their spatial distribution does not depend on the orientation of the solar wind convective electric field. We also find a clear difference in the waves occurrence rate between SPO1 and SPO2 subphases and we discuss these results in the context of possible changes in the pick up conditions associated with seasonal variations.

  18. Development of a miniature microwave electron cyclotron resonance plasma ion thruster for exospheric micro-propulsion.

    PubMed

    Dey, Indranuj; Toyoda, Yuji; Yamamoto, Naoji; Nakashima, Hideki

    2015-12-01

    A miniature microwave electron cyclotron resonance plasma source [(discharge diameter)/(microwave cutoff diameter) < 0.3] has been developed at Kyushu University to be used as an ion thruster in micro-propulsion applications in the exosphere. The discharge source uses both radial and axial magnetostatic field confinement to facilitate electron cyclotron resonance and increase the electron dwell time in the volume, thereby enhancing plasma production efficiency. Performance of the ion thruster is studied at 3 microwave frequencies (1.2 GHz, 1.6 GHz, and 2.45 GHz), for low input powers (<15 W) and small xenon mass flow rates (<40 μg/s), by experimentally measuring the extracted ion beam current through a potential difference of ≅1200 V. The discharge geometry is found to operate most efficiently at an input microwave frequency of 1.6 GHz. At this frequency, for an input power of 8 W, and propellant (xenon) mass flow rate of 21 μg/s, 13.7 mA of ion beam current is obtained, equivalent to an calculated thrust of 0.74 mN. PMID:26724025

  19. Development of a miniature microwave electron cyclotron resonance plasma ion thruster for exospheric micro-propulsion

    SciTech Connect

    Dey, Indranuj; Toyoda, Yuji; Yamamoto, Naoji; Nakashima, Hideki

    2015-12-15

    A miniature microwave electron cyclotron resonance plasma source [(discharge diameter)/(microwave cutoff diameter) < 0.3] has been developed at Kyushu University to be used as an ion thruster in micro-propulsion applications in the exosphere. The discharge source uses both radial and axial magnetostatic field confinement to facilitate electron cyclotron resonance and increase the electron dwell time in the volume, thereby enhancing plasma production efficiency. Performance of the ion thruster is studied at 3 microwave frequencies (1.2 GHz, 1.6 GHz, and 2.45 GHz), for low input powers (<15 W) and small xenon mass flow rates (<40 μg/s), by experimentally measuring the extracted ion beam current through a potential difference of ≅1200 V. The discharge geometry is found to operate most efficiently at an input microwave frequency of 1.6 GHz. At this frequency, for an input power of 8 W, and propellant (xenon) mass flow rate of 21 μg/s, 13.7 mA of ion beam current is obtained, equivalent to an calculated thrust of 0.74 mN.

  20. Digital control in LLRF system for CYCIAE-100 cyclotron

    NASA Astrophysics Data System (ADS)

    Yin, Zhiguo; Fu, Xiaoliang; Ji, Bin; Zhang, Tianjue; Wang, Chuan

    2016-05-01

    As a driven accelerator, the CYCIAE-100 cyclotron is designed by China Institute of Atomic Energy for the Beijing Radio Ion-beam Facility project. The cyclotron RF system is designed to use two RF power sources of 100 kW to drive two half-wavelength cavities respectively. Two Dee accelerating electrodes are kept separately from each other inside the cyclotron, while their accelerating voltages are maintained in phase by the efforts of LLRF control. An analog-digital hybrid LLRF system has been developed to achieve cavity tuning control, dee voltage amplitude and phase stabilization etc. The analog subsystems designs are focused on RF signal up/down conversion, tuning control, and dee voltage regulation. The digital system provides an RF signal source, aligns the cavity phases and maintains a Finite State Machine. The digital parts combine with the analog functions to provide the LLRF control. A brief system hardware introduction will be given in this paper, followed by the review of several major characteristics of the digital control in the 100 MeV cyclotron LLRF system. The commissioning is also introduced, and most of the optimization during the process was done by changing the digital parts.

  1. Electron-cyclotron-resonant-heated electron distribution functions

    SciTech Connect

    Matsuda, Y.; Nevins, W.M.; Cohen, R.H.

    1981-06-26

    Recent studies at Lawrence Livermore National Laboratory (LLNL) with a bounce-averaged Fokker-Planck code indicate that the energetic electron tail formed by electron-cyclotron resonant heating (ECRH) at the second harmonic is not Maxwellian. We present the results of our bounce-averaged Fokker-Planck code along with some simple analytic models of hot-electron distribution functions.

  2. Electron-cyclotron-heating experiments in tokamaks and stellarators

    SciTech Connect

    England, A.C.

    1983-01-01

    This paper reviews the application of high-frequency microwave radiation to plasma heating near the electron-cyclotron frequency in tokamaks and stellarators. Successful plasma heating by microwave power has been demonstrated in numerous experiments. Predicted future technological developments and current theoretical understanding suggest that a vigorous program in plasma heating will continue to yield promising results.

  3. Maryland University sectored isochronous cyclotron (MUSIC): Progress report No. 35

    SciTech Connect

    Not Available

    1986-10-29

    Efforts are reported on the installation and checkout of cyclotron components which had been previously fabricated. Final integration of subsystems and major systems leading to internal beam tests is reported near completion. Progress is reported in relation to control system components, focus and steering magnet design, and rf system testing. (LEW)

  4. Status of ECR (Electron Cyclotron Resonance) source technology

    SciTech Connect

    Lyneis, C.M.

    1987-03-01

    ECR (Electron Cyclotron Resonance) ion sources are now in widespread use for the production of high quality multiply charged ion beams for accelerators and atomic physics experiments, and industrial applications are being explored. Several general characteristics of ECR sources explain their widespread acceptance. For use with cyclotrons which require CW multiply charged ion beams, the ECR source has many advantages over heavy-ion PIG sources. Most important is the ability to produce higher charge states at useful intensities for nuclear physics experiments. Since the maximum energy set by the bending limit of a cyclotron scales with the square of the charge state, the installation of ECR sources on cyclotrons has provided an economical path to raise the energy. Another characteristic of ECR sources is that the discharge is produced without cathodes, so that only the source material injected into an ECR source is consumed. As a result, ECR sources can be operated continuously for periods of weeks without interruption. Techniques have been developed in the last few years, which allow these sources to produce beams from solid materials. The beam emittance from ECR sources is in the range of 50 to 200 ..pi.. mm-mrad at 10 kV. The principles of ECR ion sources are discussed, and present and future ECR sources are reviewed.

  5. Cyclotron targetry for production of short-lived positron emitters

    SciTech Connect

    Schlyer, D.J.

    1989-01-01

    The basic concepts of cyclotron target design are presented along with the relevant practical experience gained by workers in this field over the years. Results are presented from several recent studies on the temperature and density distribution inside gas and liquid targets. 5 refs., 3 figs.

  6. 30 Gy or 34 Gy? Comparing 2 Single-Fraction SBRT Dose Schedules for Stage I Medically Inoperable Non-Small Cell Lung Cancer

    SciTech Connect

    Videtic, Gregory M.M. Stephans, Kevin L.; Woody, Neil M.; Reddy, Chandana A.; Zhuang, Tingliang; Magnelli, Anthony; Djemil, Toufik

    2014-09-01

    Purpose: To review outcomes of 2 single-fraction lung stereotactic body radiation therapy (SBRT) schedules used for medically inoperable early stage lung cancer. Methods and Materials: Patients in our institution have been treated on and off protocols using single-fraction SBRT (30 Gy and 34 Gy, respectively). All patients had node-negative lung cancer measuring ≤5 cm and lying ≥2 cm beyond the trachea-bronchial tree and were treated on a Novalis/BrainLAB system with the ExactTrac positioning system for daily image guidance. Results: For the interval from 2009 to 2012, 80 patients with 82 lesions were treated with single-fraction lung SBRT. Fifty-five patients (69%) and 25 patients (31%) received 30 Gy and 34 Gy, respectively. In a comparison of 30 Gy and 34 Gy cohorts, patient and tumor characteristics were balanced and median follow-up in months was 18.7 and 17.8, respectively. The average heterogeneity-corrected mean doses to the target were 33.75 Gy and 37.94 Gy for the 30-Gy and 34-Gy prescriptions, respectively. Comparing 30-Gy and 34-Gy cohorts, 92.7% and 84.0% of patients, respectively, experienced no toxicity (P was not significant), and had neither grade 3 nor higher toxicities. For the 30-Gy and 34-Gy patients, rates of 1-year local failure, overall survival, and lung cancer-specific mortality were 2.0% versus 13.8%, 75.0% versus 64.0%, and 2. 1% versus 16.0%, respectively (P values for differences were not significant). Conclusions: This is the largest single-fraction lung SBRT series yet reported. and it confirms the safety, efficacy, and minimal toxicity of this schedule for inoperable early stage lung cancer.

  7. Measurement of cyclotron resonance relaxation time in the two-dimensional electron system

    SciTech Connect

    Andreev, I. V. Muravev, V. M.; Kukushkin, I. V.; Belyanin, V. N.

    2014-11-17

    Dependence of cyclotron magneto-plasma mode relaxation time on electron concentration and temperature in the two-dimensional electron system in GaAs/AlGaAs quantum wells has been studied. Comparative analysis of cyclotron and transport relaxation time has been carried out. It was demonstrated that with the temperature increase transport relaxation time tends to cyclotron relaxation time. It was also shown that cyclotron relaxation time, as opposed to transport relaxation time, has a weak electron density dependence. The cyclotron time can exceed transport relaxation time by an order of magnitude in a low-density range.

  8. Non-linear effects in electron cyclotron current drive applied for the stabilization of neoclassical tearing modes

    NASA Astrophysics Data System (ADS)

    Ayten, B.; Westerhof, E.; the ASDEX Upgrade Team

    2014-07-01

    Due to the smallness of the volumes associated with the flux surfaces around the O-point of a magnetic island, the electron cyclotron power density applied inside the island for the stabilization of neoclassical tearing modes (NTMs) can exceed the threshold for non-linear effects as derived previously by Harvey et al (1989 Phys. Rev. Lett. 62 426). We study the non-linear electron cyclotron current drive (ECCD) efficiency through bounce-averaged, quasi-linear Fokker-Planck calculations in the magnetic geometry as created by the islands. The calculations are performed for the parameters of a typical NTM stabilization experiment on ASDEX Upgrade. A particular feature of these experiments is that the rays of the EC wave beam propagate tangential to the flux surfaces in the power deposition region. The calculations show significant non-linear effects on the ECCD efficiency, when the ECCD power is increased from its experimental value of 1 MW to a larger value of 4 MW. The nonlinear effects are largest in the case of locked islands or when the magnetic island rotation period is longer than the collisional time scale. The non-linear effects result in an overall reduction of the current drive efficiency for this case with absorption of the EC power on the low-field side of the electron cyclotron resonance layer. As a consequence of the non-linear effects, also the stabilizing effect of the ECCD on the island is reduced from linear expectations.

  9. Medical scribes.

    PubMed

    Baugh, Reginald; Jones, James E; Trott, K; Takyi, Valerie E; Abbas, Jihad T

    2012-01-01

    Medical scribes and electronic health records (EHRs) are increasingly being introduced into ambulatory clinics with variable outcomes. Characteristics of a successful implementation of medical scribes are described. Tips for optimization of the composition and presentation of the EHR as well as medical processes associated with medical documentation are presented. PMID:23373160

  10. Dynamic regimes of cyclotron instability in the afterglow mode of minimum-B electron cyclotron resonance ion source plasma

    NASA Astrophysics Data System (ADS)

    Mansfeld, D.; Izotov, I.; Skalyga, V.; Tarvainen, O.; Kalvas, T.; Koivisto, H.; Komppula, J.; Kronholm, R.; Laulainen, J.

    2016-04-01

    The paper is concerned with the dynamic regimes of cyclotron instabilities in non-equilibrium plasma of a minimum-B electron cyclotron resonance ion source operated in pulsed mode. The instability appears in decaying ion source plasma shortly (1-10 ms) after switching off the microwave radiation of the klystron, and manifests itself in the form of powerful pulses of electromagnetic emission associated with precipitation of high-energy electrons along the magnetic field lines. Recently it was shown that this plasma instability causes perturbations of the extracted ion current, which limits the performance of the ion source and generates strong bursts of bremsstrahlung emission. In this article we present time-resolved diagnostics of electromagnetic emission bursts related to cyclotron instability in the decaying plasma. The temporal resolution is sufficient to study the fine structure of the dynamic spectra of the electromagnetic emission at different operating regimes of the ion source. It was found that at different values of magnetic field and heating power the dynamic spectra demonstrate common features: Decreasing frequency from burst to burst and an always falling tone during a single burst of instability. The analysis has shown that the instability is driven by the resonant interaction of hot electrons, distributed between the electron cyclotron resonance (ECR) zone and the trap center, with slow extraordinary wave propagation quasi-parallel with respect to the external magnetic field.

  11. Experimental observation of ion-cyclotron turbulence in the presence of transverse-velocity shear. Ph.D. Thesis

    SciTech Connect

    Amatucci, W.E.

    1994-01-01

    This laboratory investigation documents the influence of transverse, localized, dc electric fields (TLE) on the excitation of ion-cyclotron waves driven by magnetic field-aligned current (FAC) in a Q-machine plasma device. A segmented disk electrode, located on axis at the end of the plasma column, is used to independently control TLE and FAC in the plasma (potassium plasma, n approximately equals 10(exp 9) cm(exp {minus}3), rho(i) approximately equals 0.2 cm, T(e) = T(i) approximately equals 0.2 eV). Ion-cyclotron waves have been characterized in both the weak-TLE and large-FAC regime and the strong-TLE and small-FAC regime. The existence of a new category of oscillation identified as the inhomogeneous energy-density driven (IEDD) instability is verified based on the properties of the waves in the latter regime. In the weak-TLE regime, current-driven electrostatic ion-cyclotron (CDEIC) waves with features in qualitative agreement with previous laboratory results have been observed at sufficiently large FAC. These waves have a frequency spectrum with a single narrow spectral feature located slightly above the ion-cyclotron frequency (omega approximately equals 1.2 Omega(i)). The waves are standing in the radial direction with peak oscillation amplitude located in the center of the FAC channel and are azimuthally symmetric (m = 0). Small magnitude TLE were found to have negligible effect on the characteristics of the waves. In the strong-TLE regime, a decrease in the threshold FAC level is observed. This transition in the instability threshold is accompanied by changes in the frequency spectra, propagation characteristics, and mode amplitude profiles. In the presence of strong-TLE, the ion-cyclotron waves propagate azimuthally in the E x B direction with k(theta) rho(i) = 0.4 and m = 1. The frequency spectrum becomes broadband and spiky, and shifts with the applied TLE strength.

  12. Is second-line systemic chemotherapy beneficial in patients with non-small cell lung cancer (NSCLC)? A multicenter data evaluation by the Anatolian Society of Medical Oncology.

    PubMed

    Odabas, Hatice; Ulas, Arife; Aydin, Kubra; Inanc, Mevlude; Aksoy, Asude; Yazilitas, Dogan; Turkeli, Mehmet; Yuksel, Sinemis; Inal, Ali; Ekinci, Ahmet S; Sevinc, Alper; Demirci, Nebi S; Uysal, Mukremin; Alkis, Necati; Dane, Faysal; Aliustaoglu, Mehmet; Gumus, Mahmut

    2015-12-01

    Patients with advanced non-small cell lung cancer (NSCLC) generally require second-line treatment although their prognosis is poor. In this multicenter study, we aimed to detect the characteristics related to patients and disease that can predict the response to second-line treatments in advanced NSCLC. Data of 904 patients who have progressed after receiving first-line platinum-based chemotherapy in 11 centers with the diagnosis of stage IIIB and IV NSCLC and who were evaluated for second-line treatment were retrospectively analyzed. The role of different factors in determining the benefit of second-line treatment was analyzed. Median age of patients was 57years (range 19-86). Docetaxel was the most commonly used (20.9%, n?=?189) single agent, while gemcitabine-platinum was the most commonly used (6.7%, n?=?61) combination chemotherapy regimen in second-line setting. According to survival analysis, median progression-free survival after first-line treatment (PFS2) was 3.5months (standard error (SE) 0.2; 95% confidence interval (CI), 3.2-3.9), median overall survival (OS) was 6.7months (SE 0.3; 95% CI, 6.0-7.3). In multivariate analysis, independent factors affecting PFS2 were found to be hemoglobin (Hb) level over 12g/dl and treatment-free interval (TFI) longer than 3months (p?=?0.006 and 0.003, respectively). Similarly, in OS analysis, Hb level over 12g/dl and time elapsed after the first-line treatment that is longer than 3months were found to be independent prognostic factors (p?=?0.0001 and 0.045, respectively). In light of these findings, determining and using the parameters for which the treatment will be beneficial prior to second-line treatment can increase success rate. PMID:26150339

  13. Travel Medical Kit.

    PubMed

    Terry, Anne C; Haulman, N Jean

    2016-03-01

    "The traveler's medical kit is an essential tool for both the novice and expert traveler. It is designed to treat travel-related illness and injury and to ensure preexisting medical conditions are managed appropriately. Travelers are at increased risk for common gastrointestinal issues during travel. Respiratory illnesses make up approximately 8% of the ailments present in returned international travelers. Approximately 12% of travelers experience a travel-related skin condition. First aid treatment for minor injuries is essential to all travel medical kits. The complexity ranges from a small, simple case for the urban traveler to a larger, extensive case for wilderness travel." PMID:26900112

  14. Cyclotron production of I-123: An evaluation of the nuclear reactions which produce this isotope

    NASA Technical Reports Server (NTRS)

    Sodd, V. J.; Scholz, K. L.; Blue, J. W.; Wellman, H. N.

    1970-01-01

    The use of the various nuclear reactions is described by which I-123,a low radiation dose radiopharmaceutical, can be cyclotron-produced. Methods of directly producing I-123 and those which indirectly produce the radionuclide through the beta (+) decay of its nautral precursor, Xe-123. It is impossible to separate from the radioiodine contaminants, notably I-124, which occur in the direct method. Thus, it is preferable to produce pure I-123 from Xe-123 which is easily separated from the radioiodines. Among the characteristics of I-123 is the capability of reducing the patient dose in a thyroid uptake measurement to a very small percentage of that delivered by the more commonly used I-131.

  15. 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)

  16. Numerical study on the stabilization of neoclassical tearing modes by electron cyclotron current drive

    SciTech Connect

    Wang, Xiaoguang; Zhang, Xiaodong; Wu, Bin; Zhu, Sizheng; Hu, Yemin

    2015-02-15

    It is well known that electron cyclotron current drive (ECCD) around the o-point of magnetic island along the plasma current direction can stabilize neoclassical tearing modes (NTMs) in tokamak devices. The effects of the radial misalignment between the island and the driven current, the phase misalignment, and the on-duty ratio for modulated current drive on NTM stabilization are studied numerically in this paper. A small radial misalignment is found to significantly decrease the stabilizing effect. When a sufficiently large phase misalignment occurs for the modulated ECCD, the stabilization effect is also reduced a lot. The optimal on-duty ratio of modulated ECCD to stabilize NTMs is found to be in the range of 60%–70%. A larger on-duty ratio than 50% could also mitigate the effect of phase misalignment if it is not too large. There is no benefit from modulation if the phase misalignment is larger than a threshold.

  17. Magnetic field calculation for a 10 MeV positron emission tomography cyclotron

    SciTech Connect

    Chen Dezhi; Liu Kaifeng; Yang Jun; Li Dong; Qin Bin; Xiong Yongqian; Chen Zihao

    2013-05-15

    The magnetic field calculation and correction for a 10 MeV positron emission tomography cyclotron is presented. 3D TOSCA analysis results are compared with the measured data, and the calculation error is used to calibrate the B-H curve to obtain a very precise finite element method estimator, which is used to predict the correction of the magnet pole for achieving the isochronous field. The isochronous field error is approximated with the effects of a set of standard patches. On the assumption that the effect of each small patch is proportional to its surface, the correction of the magnet pole is found by solving a system of equations using the least square scheme. The magnet shimming is performed and the measured magnetic field is found in good agreement with the prediction, with an error less than 2 G.

  18. Numerical study on the stabilization of neoclassical tearing modes by electron cyclotron current drive

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoguang; Zhang, Xiaodong; Wu, Bin; Zhu, Sizheng; Hu, Yemin

    2015-02-01

    It is well known that electron cyclotron current drive (ECCD) around the o-point of magnetic island along the plasma current direction can stabilize neoclassical tearing modes (NTMs) in tokamak devices. The effects of the radial misalignment between the island and the driven current, the phase misalignment, and the on-duty ratio for modulated current drive on NTM stabilization are studied numerically in this paper. A small radial misalignment is found to significantly decrease the stabilizing effect. When a sufficiently large phase misalignment occurs for the modulated ECCD, the stabilization effect is also reduced a lot. The optimal on-duty ratio of modulated ECCD to stabilize NTMs is found to be in the range of 60%-70%. A larger on-duty ratio than 50% could also mitigate the effect of phase misalignment if it is not too large. There is no benefit from modulation if the phase misalignment is larger than a threshold.

  19. Nonlinear response of magnetic islands to localized electron cyclotron current injection

    SciTech Connect

    Borgogno, D.; Comisso, L.; Grasso, D.; Lazzaro, E.

    2014-06-15

    The magnetic island evolution under the action of a current generated externally by electron cyclotron wave beams is studied using a reduced resistive magnetohydrodynamics plasma model. The use of a two-dimensional reconnection model shows novel features of the actual nonlinear evolution as compared to the zero-dimensional model of the generalized Rutherford equation. When the radio frequency control is applied to a small magnetic island, the complete annihilation of the island width is followed by a spatial phase shift of the island, referred as “flip” instability. On the other hand, a current-drive injection in a large nonlinear island can be accompanied by the occurrence of a Kelvin-Helmholtz instability. These effects need to be taken into account in designing tearing mode control systems based on radio frequency current-drive.

  20. Improved ion optics for introduction of ions into a 9.4-T Fourier transform ion cyclotron resonance mass spectrometer

    SciTech Connect

    Chen, Yu; Leach, Franklin E.; Kaiser, Nathan K.; Dang, Xibei; Ibrahim, Yehia M.; Norheim, Randolph V.; Anderson, Gordon A.; Smith, Richard D.; Marshall, Alan G.

    2015-01-01

    Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry provides unparalleled mass accuracy and resolving power.[1],[2] With electrospray ionization (ESI), ions are typically transferred into the mass spectrometer through a skimmer, which serves as a conductance-limiting orifice. However, the skimmer allows only a small fraction of incoming ions to enter the mass spectrometer. An ion funnel, originally developed by Smith and coworkers at Pacific Northwest National Laboratory (PNNL)[3-5] provides much more efficient ion focusing and transfer. The large entrance aperture of the ion funnel allows almost all ions emanating from a heated capillary to be efficiently captured and transferred, resulting in nearly lossless transmission.

  1. Cyclotron transition line-width due to interactions with the flexural wave of a phonon confined in a quantum well

    NASA Astrophysics Data System (ADS)

    Kang, Nam Lyong

    2016-03-01

    The cyclotron transition line-width for a system of electrons interacting with the flexural wave of phonons confined in a quantum well structure of silicon was calculated using the optical conductivity formula derived by the projection-reduction method. Only a few confined phonons with low energy make a significant contribution to the line-width, which increases with increasing temperature. The well width and magnetic field dependence of the line-width are complicated and the flexural mode contributes to the line-width more strongly than the dilatational mode at low magnetic fields and for small well widths.

  2. MEDICAL "DEPRIVATION."

    ERIC Educational Resources Information Center

    SUCHMAN, EDWARD A.

    THE SOCIAL AND MEDICAL PROBLEM TODAY HAS SHIFTED FROM PROVIDING FOR THE EMERGENCY MEDICAL NEEDS OF THE INDIGENT SICK TO RAISING THE LEVEL OF LOWER CLASS PARTICIPATION IN THE BENEFITS OF MODERN MEDICINE. GREATER ATTENTION IS BEING FOCUSED ON MEDICAL DEPRIVATION SUFFERED BY LARGE SEGMENTS OF THE POPULATION WHO DO NOT SHARE EQUALLY IN MEDICAL…

  3. LH wave absorption by mode conversion near ion cyclotron harmonics

    SciTech Connect

    Ko, K.; Bers, A.; Fuchs, V.

    1981-02-01

    Numerical studies of the dispersion relation near the lower-hybrid frequency in an inhomogeneous plasma (..delta.. n, ..delta.. T, ..delta.. B) show that portions of an incident lower-hybrid wave spectrum undergo successive but partial mode conversions to warm-plasma waves in the presence of ion cyclotron harmonics. Wave absorption beyond the first mode conversion occurs near an ion cyclotron harmonic where ion Landau damping is enhanced. A second-order dispersion relation numerically in good agreement with the full dispersion relation in the mode conversion region is derived using the condition par. delta D/par. delta k = 0. The mode conversion efficiency at each confluence is evaluated by solving the corresponding differential equation.

  4. Nonlinear particle simulation of ion cyclotron waves in toroidal geometry

    NASA Astrophysics Data System (ADS)

    Kuley, A.; Bao, J.; Lin, Z.; Wei, X. S.; Xiao, Y.

    2015-12-01

    Global particle simulation model has been developed in this work to provide a first-principles tool for studying the nonlinear interactions of radio frequency (RF) waves with plasmas in tokamak. In this model, ions are considered as fully kinetic particles using the Vlasov equation and electrons are treated as guiding centers using the drift kinetic equation with realistic electron-to-ion mass ratio. Boris push scheme for the ion motion has been developed in the toroidal geometry using magnetic coordinates and successfully verified for the ion cyclotron and ion Bernstein waves in global gyrokinetic toroidal code (GTC). The nonlinear simulation capability is applied to study the parametric decay instability of a pump wave into an ion Bernstein wave side band and a low frequency ion cyclotron quasi mode.

  5. Neutron spectra due (13)N production in a PET cyclotron.

    PubMed

    Benavente, J A; Vega-Carrillo, H R; Lacerda, M A S; Fonseca, T C F; Faria, F P; da Silva, T A

    2015-05-01

    Monte Carlo and experimental methods have been used to characterize the neutron radiation field around PET (Positron Emission Tomography) cyclotrons. In this work, the Monte Carlo code MCNPX was used to estimate the neutron spectra, the neutron fluence rates and the ambient dose equivalent (H*(10)) in seven locations around a PET cyclotron during (13)N production. In order to validate these calculations, H*(10) was measured in three sites and were compared with the calculated doses. All the spectra have two peaks, one above 0.1MeV due to the evaporation neutrons and another in the thermal region due to the room-return effects. Despite the relatively large difference between the measured and calculated H*(10) for one point, the agreement was considered good, compared with that obtained for (18)F production in a previous work. PMID:25699664

  6. Aharonov-Bohm effect in cyclotron and synchrotron radiations

    NASA Astrophysics Data System (ADS)

    Bagrov, V. G.; Gitman, D. M.; Levin, A.; Tlyachev, V. B.

    2001-07-01

    We study the impact of Aharonov-Bohm solenoid on the radiation of a charged particle moving in a constant uniform magnetic field. With this aim in view, exact solutions of Klein-Gordon and Dirac equations are found in the magnetic-solenoid field. Using such solutions, we calculate exactly all the characteristics of one-photon spontaneous radiation both for spinless and spinning particle. Considering non-relativistic and relativistic approximations, we analyze cyclotron and synchrotron radiations in detail. Radiation peculiarities caused by the presence of the solenoid may be considered as a manifestation of Aharonov-Bohm effect in the radiation. In particular, it is shown that new spectral lines appear in the radiation spectrum. Due to angular distribution peculiarities of the radiation intensity, these lines can in principle be isolated from basic cyclotron and synchrotron radiation spectra.

  7. Ion Behavior in an Electrically Compensated Ion Cyclotron Resonance Trap

    PubMed Central

    Brustkern, Adam M.; Rempel, Don L.; Gross, Michael L.

    2010-01-01

    We recently described a new electrically compensated trap in FT ion cyclotron resonance mass spectrometry and developed a means of tuning traps of this general design. Here, we describe a continuation of that research by comparing the ion transient lifetimes and the resulting mass resolving powers and signal-to-noise (S/N) ratios that are achievable in the compensated vs. uncompensated modes of this trap. Transient lifetimes are ten times longer under the same conditions of pressure, providing improved mass resolving power and S/N ratios. The mass resolving power as a function of m/z is linear (log-log plot) and nearly equal to the theoretical maximum. Importantly, the ion cyclotron frequency as a function of ion number decreases linearly in accord with theory, unlike its behavior in the uncompensated mode. This linearity should lead to better control in mass calibration and increased mass accuracy than achievable in the uncompensated mode. PMID:21499521

  8. Heating by waves in the ion cyclotron frequency range

    SciTech Connect

    Koch, R.

    1996-03-01

    The main aspects of heating with the fast wave in the ion cyclotron range of frequencies (ICRF) are reviewed. First, the ion cyclotron resonance mechanism, fundamental and harmonics, is examined. Then the properties of fast wave dispersion are reviewed, and the principles of minority and higher cylcotron harmonic heating are discussed. An elementary coupling model is worked out in order to outline the computation of the electrical properties of ICRF antennas. Using the simple model, the antenna radiation pattern inside the plasma is computed and the effect of phasing on the k spectrum and on the antenna radiation properties is illustrated. The quasi linear-Fokker-Planck computation of the deformation of distribution functions due to Radio-Frequency (RF) and tail formation are briefly discussed. 11 refs., 5 figs.

  9. Radiation protection aspects of the operation in a cyclotron facility

    NASA Astrophysics Data System (ADS)

    Silva, P. P. N.; Carneiro, J. C. G. G.

    2014-02-01

    The activated accelerator cyclotron components and the radioisotope production may impact on the personnel radiation exposure of the workers during the routine maintenance and emergency repair procedures and any modification of the equipment. Since the adherence of the principle of ALARA (as low as reasonable achievable) constitutes a major objective of the cyclotron management, it has become imperative to investigate the radiation levels at the workplace and the probable health effects to the worker caused by radiation exposure. The data analysis in this study was based on the individual monitoring records during the period from 2007 to 2011. Monitoring of the workplace was also performed using gamma and neutron detectors to determine the dose rate in various predetermined spots. The results of occupational radiation exposures were analysed and compared with the values established in national standards and international recommendations. Important guidelines have been developed to reduce the individual dose.

  10. Coulomb bremsstrahlung and cyclotron emissivity in hot magnetized plasmas

    NASA Astrophysics Data System (ADS)

    Nagel, W.; Ventura, J.

    1983-02-01

    The population of Landau levels for electrons in pulsar magnetic fields is examined using a simplified two level model as part of an investigation of the formation of cyclotron lines in spectra of X-ray pulsars and gamma-ray bursts. The population of the level in the outermost radiating layers is non-LTE, similar to the situation in stellar atmospheres, and is determined by the number of line photons diffusing from the interior. The medium emissivity is related to the free-free absorption coefficient using an equivalent Kirchoff law, and the resonant part of this emissivity gives the cyclotron emissivity, which can be less than its usual LTE value. The free-free emission and absorption coefficients are anisotropic and polarization dependent in the continuum. A qualitatively new resonance behavior in the bremsstrahlung coefficients is found in the contribution from electrons occupying excited Landau levels, with quantum numbers n greater than or equal to 1.

  11. Pencil Beam Scanning System Based On A Cyclotron

    SciTech Connect

    Tachikawa, Toshiki; Nonaka, Hideki; Kumata, Yukio; Nishio, Teiji; Ogino, Takashi

    2011-06-01

    Sumitomo Heavy Industries, Ltd. (SHI) has developed a new pencil beam scanning system (PBS) for proton therapy in collaboration with National Cancer Center Hospital East (NCCHE). Taking advantage of the continuous beam from the cyclotron P235, the line scanning method is employed in order to realize continuous irradiation with high dose rate. 3D uniform and sphere field was irradiated and compared with the simulation.

  12. Study of selective heating at ion cyclotron resonance

    NASA Astrophysics Data System (ADS)

    Compant La Fontaine, A.

    1996-02-01

    In order to achieve effective isotopic separation by the Plasma Separation Process (PSP) near the ion cyclotron resonance, experiments are performed on the ERIC device,1,2 and in parallel theory is developed. Some recent results dealing with the basic properties of the electromagnetic wave induced in the plasma are presented. Also the conditions for which the heating is the most selective are given. In addition experimental measurements of ionic temperatures of resonant isotopes are compared with theoretical results.

  13. Formation of cyclotron lines in gamma-ray burst spectra

    NASA Technical Reports Server (NTRS)

    Alexander, S. G.; Meszaros, P.

    1989-01-01

    A transmission model of gamma-ray burst sources is studied using the relativistic QED magnetic-resonant opacities including multiple photon scattering, incorporated into a discrete-ordinate radiative-transport scheme. The physics of the cyclotron line-producing region is discussed in general, and the expected line profiles, relative harmonic strengths, and polarizations are indicated under various conditions. The calculated spectra for these models show good agreement with the spectra reported from Ginga for GB 880205 and GB 870303.

  14. RF physics of ICWC discharge at high cyclotron harmonics

    NASA Astrophysics Data System (ADS)

    Lyssoivan, A.; van Eester, D.; Wauters, T.; Bobkov, V.; Vervier, M.; Douai, D.; Kogut, D.; Kreter, A.; Moiseenko, V.; Möller, S.; Noterdaeme, J.-M.; Philipps, V.; Rohde, V.; Schneider, P.; Sergienko, G.; van Schoor, M.; Textor Team, ASDEX Upgrade Team

    2014-02-01

    Recent experiments on Ion Cyclotron Wall Conditioning (ICWC) performed in tokamaks TEXTOR and ASDEX Upgrade with standard ICRF antennas operated at fixed frequencies but variable toroidal magnetic field demonstrated rather contrasting parameters of ICWC discharge in scenarios with on-axis fundamental ion cyclotron resonance (ICR) for protons,ω=ωH+, and with its high cyclotron harmonics (HCH), ω=10ωcH+ṡ HCH scenario: very high antenna coupling to low density RF plasmas (Ppl≈0.9PRF-G) and low energy Maxwellian distribution of CX hydrogen atoms with temperature TH≈350 eV. Fundamental ICR: lower antenna-plasma coupling efficiency (by factor of about 1.5 times) and generation of high energy non-Maxwellian CX hydrogen atoms (with local energy E⊥H ≥1.0 keV). In the present paper, we analyze the obtained experimental results numerically using (i) newly developed 0-D transport code describing the process of plasma production with electron and ion collisional ionization in helium-hydrogen gas mixture and (ii) earlier developed 1-D Dispersion Relation Solver accounting for finite temperature effects and collision absorption mechanisms for all plasma species in addition to conventionally examined Landau/TTPM damping for electrons and cyclotron absorption for ions. The numerical study of plasma production in helium with minor hydrogen content in low and high toroidal magnetic fields is presented. The investigation of the excitation, conversion and absorption of plasma waves as function of BT-field suggests that only fast waves (FW) may give a crucial impact on antenna coupling and characteristics of the ICWC discharge using standard poloidally polarized ICRF antennas designed to couple RF power mainly to FW. The collisional (non-resonant) absorption by electrons and ions and IC absorption by resonant ions of minor concentration in low Te plasmas is studied at fundamental ICR and its high harmonics.

  15. GX 339-4 - Cyclotron radiation from an accretion flow

    NASA Astrophysics Data System (ADS)

    Fabian, A. C.; Guilbert, P. W.; Motch, C.; Ricketts, M.; Ilovaisky, S. A.; Chevalier, C.

    1982-07-01

    It is shown that the fast optical flares recently discovered in the Galactic X-ray source GX 339-4 are probably due to the cyclotron emission from hot gas at 10 to the 9th K. The inner accretion flow appears to be very similar to that in Cygnus X-1. Optical polarization may be detectable and further studies may help to study the metric close to the compact object.

  16. Converting an AEG Cyclotron to H- Acceleration and Extraction

    NASA Astrophysics Data System (ADS)

    Ramsey, Fred; Carroll, Lewis; Rathmann, Tom; Huenges, Ernst; Bechtold, Matthias Mentler Volker

    2009-03-01

    Clinical Trials are under way to evaluate agents labeled with the nuclide 225Ac and its decay product 213Bi, in targeted alpha-immuno-therapy [1]. 225Ac can be produced on a medium-energy cyclotron via the nuclear reaction 226Ra(p,n)225Ac. To demonstrate proof-of-principle, a vintage AEG cyclotron, Model E33 [2], with an internal target, had been employed in a pilot production program at the Technical University of Munich (TUM). To enhance production capability and further support the clinical studies, the TUM facility has recently been refurbished and upgraded, adding a new external beam-line, automated target irradiation and transport systems, new laboratories, hot cells, etc. [3]. An improved high-power rotating target has been built and installed [4]. The AEG cyclotron itself has also been modified and upgraded to accelerate and extract H- ions. We have designed, built, and tested a new axial Penning-type ion source which is optimized for the production of H- ions. The ion source has continued to evolve through experiment and experience. Steady improvements in materials and mechanics have led to enhanced source stability, life-time, and H- production. We have also designed and built a precision H- charge-exchange beam-extraction system which is equipped with a vacuum lock. To fit within the tight mechanical constraint imposed by the narrow magnet gap, the system incorporates a novel chain-drive foil holder and foil-changer mechanism. The reconfigured cyclotron system has now been in operation for more than 1 year. Three long-duration target irradiations have been conducted. The most recent bombardment ran 160 continuous hours at a beam on target of ˜80 microamperes for a total yield of ˜70 milli-curies of 225Ac.

  17. Fourier transform ion cyclotron resonance mass resolution and dynamic range limits calculated by computer modeling of ion cloud motion.

    PubMed

    Vladimirov, Gleb; Hendrickson, Christopher L; Blakney, Greg T; Marshall, Alan G; Heeren, Ron M A; Nikolaev, Eugene N

    2012-02-01

    Particle-in-Cell (PIC) ion trajectory calculations provide the most realistic simulation of Fourier transform ion cyclotron resonance (FT-ICR) experiments by efficient and accurate calculation of the forces acting on each ion in an ensemble (cloud), including Coulomb interactions (space charge), the electric field of the ICR trap electrodes, image charges on the trap electrodes, the magnetic field, and collisions with neutral gas molecules. It has been shown recently that ion cloud collective behavior is required to generate an FT-ICR signal and that two main phenomena influence mass resolution and dynamic range. The first is formation of an ellipsoidal ion cloud (termed "condensation") at a critical ion number (density), which facilitates signal generation in an FT-ICR cell of arbitrary geometry because the condensed cloud behaves as a quasi-ion. The second phenomenon is peak coalescence. Ion resonances that are closely spaced in m/z coalesce into one resonance if the ion number (density) exceeds a threshold that depends on magnetic field strength, ion cyclotron radius, ion masses and mass difference, and ion initial spatial distribution. These two phenomena decrease dynamic range by rapid cloud dephasing at small ion density and by cloud coalescence at high ion density. Here, we use PIC simulations to quantitate the dependence of coalescence on each critical parameter. Transitions between independent and coalesced motion were observed in a series of the experiments that systematically varied ion number, magnetic field strength, ion radius, ion m/z, ion m/z difference, and ion initial spatial distribution (the present simulations begin from elliptically-shaped ion clouds with constant ion density distribution). Our simulations show that mass resolution is constant at a given magnetic field strength with increasing ion number until a critical value (N) is reached. N dependence on magnetic field strength, cyclotron radius, ion mass, and difference between ion masses was determined for two ion ensembles of different m/z, equal abundance, and equal cyclotron radius. We find that N and dynamic range depend quadratically on magnetic field strength in the range 1-21 Tesla. Dependences on cyclotron radius and ?m/z are linear. N depends on m/z as (m/z)(-2). Empirical expressions for mass resolution as a function of each of the experimental parameters are presented. Here, we provide the first exposition of the origin and extent of trade-off between FT-ICR MS dynamic range and mass resolution (defined not as line width, but as the separation between the most closely resolved masses). PMID:22033889

  18. Fourier Transform Ion Cyclotron Resonance Mass Resolution and Dynamic Range Limits Calculated by Computer Modeling of Ion Cloud Motion

    NASA Astrophysics Data System (ADS)

    Vladimirov, Gleb; Hendrickson, Christopher L.; Blakney, Greg T.; Marshall, Alan G.; Heeren, Ron M. A.; Nikolaev, Eugene N.

    2012-02-01

    Particle-in-Cell (PIC) ion trajectory calculations provide the most realistic simulation of Fourier transform ion cyclotron resonance (FT-ICR) experiments by efficient and accurate calculation of the forces acting on each ion in an ensemble (cloud), including Coulomb interactions (space charge), the electric field of the ICR trap electrodes, image charges on the trap electrodes, the magnetic field, and collisions with neutral gas molecules. It has been shown recently that ion cloud collective behavior is required to generate an FT-ICR signal and that two main phenomena influence mass resolution and dynamic range. The first is formation of an ellipsoidal ion cloud (termed "condensation") at a critical ion number (density), which facilitates signal generation in an FT-ICR cell of arbitrary geometry because the condensed cloud behaves as a quasi-ion. The second phenomenon is peak coalescence. Ion resonances that are closely spaced in m/z coalesce into one resonance if the ion number (density) exceeds a threshold that depends on magnetic field strength, ion cyclotron radius, ion masses and mass difference, and ion initial spatial distribution. These two phenomena decrease dynamic range by rapid cloud dephasing at small ion density and by cloud coalescence at high ion density. Here, we use PIC simulations to quantitate the dependence of coalescence on each critical parameter. Transitions between independent and coalesced motion were observed in a series of the experiments that systematically varied ion number, magnetic field strength, ion radius, ion m/z, ion m/z difference, and ion initial spatial distribution (the present simulations begin from elliptically-shaped ion clouds with constant ion density distribution). Our simulations show that mass resolution is constant at a given magnetic field strength with increasing ion number until a critical value (N) is reached. N dependence on magnetic field strength, cyclotron radius, ion mass, and difference between ion masses was determined for two ion ensembles of different m/z, equal abundance, and equal cyclotron radius. We find that N and dynamic range depend quadratically on magnetic field strength in the range 1-21 Tesla. Dependences on cyclotron radius and Δ m/z are linear. N depends on m/z as ( m/z)-2. Empirical expressions for mass resolution as a function of each of the experimental parameters are presented. Here, we provide the first exposition of the origin and extent of trade-off between FT-ICR MS dynamic range and mass resolution (defined not as line width, but as the separation between the most closely resolved masses).

  19. 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.

  20. 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.

  1. A Suzaku View of Cyclotron Line Sources and Candidates

    NASA Technical Reports Server (NTRS)

    Pottschmidt, K.; Suchy, S.; Rivers, E.; Rothschild, R. E.; Marcu, D. M.; Barragan, L.; Kuehnel, M.; Fuerst, F.; Schwarm, F.; Kreykenbohm, I.; Wilms, J.; Schoenherr, G.; Caballero, I.; Camero-Arranz, A.; Bodaghee, A.; Doroshenko, V.; Klochkov, D.; Santangelo, A.; Staubert, R.; Kretschmar, P.; Wilson-Hodge, C.; Finger, M. H.; Terada, Y.

    2012-01-01

    Seventeen accreting neutron star pulsars, mostly high mass X-ray binaries with half of them Be-type transients, are known to exhibit Cyclotron Resonance Scattering Features (CRSFs) in their X-ray spectra, with characteristic line energies from 10 to 60 keY. To date about two thirds of them, plus a few similar systems without known CRSFs, have been observed with Suzaku. We present an overview of results from these observations, including the discovery of a CRSF in the transient IA1118-61 and pulse phase resolved spectroscopy of OX 301-2. These observations allow for the determination of cyclotron line parameters to an unprecedented degree of accuracy within a moderate amount of observing time. This is important since these parameters vary - e.g., with orbital phase, pulse phase, or luminosity - depending on the geometry of the magnetic field of the pulsar and the properties of the accretion column at the magnetic poles. We briefly introduce a spectral model for CRSFs that is currently being developed and that for the first time is based on these physical properties. In addition to cyclotron line measurements, selected highlights from the Suzaku analyses include dip and flare studies, e.g., of 4U 1907+09 and Vela X-I, which show clumpy wind effects (like partial absorption and/or a decrease in the mass accretion rate supplied by the wind) and may also display magnetospheric gating effects.

  2. Cyclotron electron beam excited surface plasmon polaritons coherent radiation

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    A physical mechanism of electron beam excitation of surface plasmon polaritons (SPPs) on the circular cylindrical structure and transformation into coherent radiation is proposed. Here SPPs on the circular cylindrical structures are excited by a cyclotron electron beam (CEB) rather than by the linearly moving electron beam (LEB). This change leads to an essential consequence due to the natural periodicity of 2? in structure and CEB, and this dual natural periodicity makes the SPPs transformation possible and brings significant excellences. HEM hybrid modes and \\text{TM}0n modes SPPs can be excited and propagate along a cyclotron trajectory together with the CEB to attract energy from CEB continuously to compensate the energy loss; the phase velocity of SPPs synchronizes the CEB; the process of the excitation and transformation is longer. Therefore, the transformed power density is enhanced and reaches up to 1010 \\text{W/cm}2 . The cyclotron frequency of the electron beam is 1 THz, but the frequency regime of the SPPs and the radiation are much higher, up to hundreds of terahertz. The mechanism presented in this letter opens the way for developing the desired room temperature, powerful and coherent light radiation sources from the infrared to the ultraviolet frequency regime.

  3. Improving cancer treatment with cyclotron produced radionuclides. Progress report

    SciTech Connect

    Larson, S.M.; Finn, R.D.

    1992-08-04

    Our goal is to improve the scientific basis for tumor diagnosis, treatment and treatment follow-up based on the use of cyclotron produced radiotracers in oncology. The grant includes 3 interactive components: Radiochemistry/Cyclotron; Pharmacology; and Immunology. The radiochemistry group seeks to develop innovative cyclotron targetry, radiopharmaceuticals, and radiolabeled antibodies, which are then used to assess important unanswered questions in tumor pharmacology and immunology. Examples include selected positron emitting radionuclides, such as Iodine-124, and Ga-66; I-124, I-123, I-131 labeled iododeoxyuridine, C-11 colchicine, and antimetabolites, like C-11 methotrexate; and radiolabeled antibodies, 3F8, M195, A33, and MRK16 for application in the pharmacology and immunology projects. The pharmacology program studies tumor resistance to chemotherapy, particularly the phenomenon of multidrug resistance and the relationship between tumor uptake and retention and the tumor response for anti-metabolite drugs. The immunology program studies the physiology of antibody localization at the tissue level as the basis for novel approaches to improving tumor localization such as through the use of an artificial lymphatic system which mechanically reduces intratumoral pressures in tumors in vivo. Quantitative imaging approaches based on PET and SPECT in radioimmunotherapy are studied to give greater insight into the physiology of tumor localization and dosimetry.

  4. Accelerator science in medical physics

    PubMed Central

    Peach, K; Wilson, P; Jones, B

    2011-01-01

    The use of cyclotrons and synchrotrons to accelerate charged particles in hospital settings for the purpose of cancer therapy is increasing. Consequently, there is a growing demand from medical physicists, radiographers, physicians and oncologists for articles that explain the basic physical concepts of these technologies. There are unique advantages and disadvantages to all methods of acceleration. Several promising alternative methods of accelerating particles also have to be considered since they will become increasingly available with time; however, there are still many technical problems with these that require solving. This article serves as an introduction to this complex area of physics, and will be of benefit to those engaged in cancer therapy, or who intend to acquire such technologies in the future. PMID:22374548

  5. Considerations, measurements and logistics associated with low-energy cyclotron decommissioning

    NASA Astrophysics Data System (ADS)

    Sunderland, J. J.; Erdahl, C. E.; Bender, B. R.; Sensoy, L.; Watkins, G. L.

    2012-12-01

    The University of Iowa's 20-year-old 17 MeV Scanditronix cyclotron underwent decommissioning in the summer of 2011. To satisfy local, state and federal regulations defining removal, transportation and long-term safe and environmentally secure disposal of the 22 ton activated cyclotron, a series of nuclear spectroscopic measurements were performed to characterize the nature and extent of proton and neutron activation of the 22-ton cyclotron, its associated targets, and the concrete wall that was demolished to remove the old cyclotron. Neutron activation of the concrete wall was minimal and below exempt concentrations resulting in standard landfill disposal. The cyclotron assessment revealed the expected array of short and medium-lived radionuclides. Subsequent calculations suggest that meaningful levels residual activity will have decayed virtually to background after 15 years, with the total residual activity of the entire cyclotron dropping below 37 MBq (1 mCi).

  6. Whistler and Alfvén Mode Cyclotron Masers in Space

    NASA Astrophysics Data System (ADS)

    Trakhtengerts, V. Y.; Rycroft, M. J.

    2012-10-01

    Preface; 1. Introduction; 2. Basic theory of cyclotron masers (CMs); 3. Linear theory of the cyclotron instability (CI); 4. Backward wave oscillator (BWO) regime in CMs; 5. Nonlinear cyclotron wave-particle interactions for a quasi-monochromatic wave; 6. Nonlinear interaction of quasi-monochromatic whistler mode waves with gyroresonant electrons in an in homogeneous plasma; 7. Wavelet amplification in an inhomogeneous plasma; 8. Quasi-linear theory of cyclotron masers; 9. Nonstationary generation regimes, and modulation effects; 10. ELF/VLF noise-like emissions and electrons in the Earth's radiation belts; 11. Generation of discrete ELF/VLF whistler mode emissions; 12. Cyclotron instability of the proton radiation belts; 13. Cyclotron masers elsewhere in the solar system and in laboratory plasma devices; Epilogue; Glossary of terms; List of acronyms; References; Index.

  7. Considerations, measurements and logistics associated with low-energy cyclotron decommissioning

    SciTech Connect

    Sunderland, J. J.; Erdahl, C. E.; Bender, B. R.; Sensoy, L.; Watkins, G. L.

    2012-12-19

    The University of Iowa's 20-year-old 17 MeV Scanditronix cyclotron underwent decommissioning in the summer of 2011. To satisfy local, state and federal regulations defining removal, transportation and long-term safe and environmentally secure disposal of the 22 ton activated cyclotron, a series of nuclear spectroscopic measurements were performed to characterize the nature and extent of proton and neutron activation of the 22-ton cyclotron, its associated targets, and the concrete wall that was demolished to remove the old cyclotron. Neutron activation of the concrete wall was minimal and below exempt concentrations resulting in standard landfill disposal. The cyclotron assessment revealed the expected array of short and medium-lived radionuclides. Subsequent calculations suggest that meaningful levels residual activity will have decayed virtually to background after 15 years, with the total residual activity of the entire cyclotron dropping below 37 MBq (1 mCi).

  8. Modeling radio scattering and scintillation observations of the inner solar wind using oblique Alfvén/ion cyclotron waves

    NASA Astrophysics Data System (ADS)

    Harmon, John K.; Coles, William A.

    2005-03-01

    Radio scattering and scintillation observations of the near-Sun solar wind are shown to be dominated by effects associated with obliquely propagating Alfvén/ion cyclotron waves. We base this on a modeling of structure functions from angular/spectral broadening observations and velocity measurements from interplanetary scintillation (IPS) observations. A simple damped-WKB model was found inadequate, as Landau damping erodes the spectrum faster than is consistent with the observed inner scale. Invoking a turbulent cascade can counteract this damping and push the spectral cutoff back out to the observed inner scale near the ion inertial scale. Adjusting the spectrum amplitude and cascade rate to match observations gives an estimate of the wave dissipation power associated with electron Landau damping and proton cyclotron damping. The implied power levels are substantial, being comparable with levels typically invoked in extended wave heating models. Both the shape and the amplitude of the observed structure functions can be explained by a composite spectrum made up of a power law component of passive or non-Alfvénic density fluctuations and a local flattening associated with the enhanced linear Alfvén wave compressibility at small (ion cyclotron) scales. Since IPS is dominated by the enhanced small-scale density fluctuations, the scintillation velocity field should show a strong wave effect. Our modeling of IPS velocities does, in fact, show that the large parallel velocity spread and upward bias to the mean velocity observed near the Sun are a direct result of the density fluctuations associated with Alfvén waves along an extended line of sight.

  9. On nonlinear effects in electron-cyclotron resonance plasma heating by microwave radiation

    SciTech Connect

    Litvak, A.G.; Sergeev, A.M.; Suvorov, E.V.; Tokman, M.D.; Khazanov, I.V. )

    1993-12-01

    Possible nonlinear effects in electron-cyclotron plasma production and heating by microwave radiation are analyzed. They include nonlinear regimes of electron acceleration in strong microwave fields under cyclotron resonance conditions, nonstationary regimes of microwave beam self-focusing, and some parametric processes. Presented results may be of importance for predictions of plasma response to electron-cyclotron resonance (ECR) heating or preionization by powerful radiation.

  10. Microwave emission related to cyclotron instabilities in a minimum-B electron cyclotron resonance ion source plasma

    NASA Astrophysics Data System (ADS)

    Izotov, I.; Tarvainen, O.; Mansfeld, D.; Skalyga, V.; Koivisto, H.; Kalvas, T.; Komppula, J.; Kronholm, R.; Laulainen, J.

    2015-08-01

    Electron cyclotron resonance ion sources (ECRIS) have been essential in the research and applications of nuclear physics over the past 40 years. They are extensively used in a wide range of large-scale accelerator facilities for the production of highly charged heavy ion beams of stable and radioactive elements. ECRISs are susceptible to kinetic instabilities due to resonance heating mechanism leading to anisotropic electron velocity distribution function. Instabilities of cyclotron type are a proven cause of frequently observed periodic bursts of ‘hot’ electrons and bremsstrahlung, accompanied with emission of microwave radiation and followed by considerable drop of multiply charged ions current. Detailed studies of the microwave radiation associated with the instabilities have been performed with a minimum-B 14 GHz ECRIS operating on helium, oxygen and argon plasmas. It is demonstrated that during the development of cyclotron instability ‘hot’ electrons emit microwaves in sub-microsecond scale bursts at temporally descending frequencies in the 8-15 GHz range with two dominant frequencies of 11.09 and 12.59 GHz regardless of ECRIS settings i.e. magnetic field strength, neutral gas pressure or species and microwave power. The experimental data suggest that the most probable excited plasma wave is a slow extraordinary Z-mode propagating quasi-longitudinally with respect to the external magnetic field.

  11. Linear and nonlinear physics of the magnetoacoustic cyclotron instability of fusion-born ions in relation to ion cyclotron emission

    SciTech Connect

    Carbajal, L. Cook, J. W. S.; Dendy, R. O.; Chapman, S. C.; Department of Mathematics and Statistics, University of Troms, N-9037, Troms; Max Planck Institute for the Physics of Complex Systems, D-01187, Dresden

    2014-01-15

    The magnetoacoustic cyclotron instability (MCI) probably underlies observations of ion cyclotron emission (ICE) from energetic ion populations in tokamak plasmas, including fusion-born alpha-particles in JET and TFTR [Dendy et al., Nucl. Fusion 35, 1733 (1995)]. ICE is a potential diagnostic for lost alpha-particles in ITER; furthermore, the MCI is representative of a class of collective instabilities, which may result in the partial channelling of the free energy of energetic ions into radiation, and away from collisional heating of the plasma. Deep understanding of the MCI is thus of substantial practical interest for fusion, and the hybrid approximation for the plasma, where ions are treated as particles and electrons as a neutralising massless fluid, offers an attractive way forward. The hybrid simulations presented here access MCI physics that arises on timescales longer than can be addressed by fully kinetic particle-in-cell simulations and by analytical linear theory, which the present simulations largely corroborate. Our results go further than previous studies by entering into the nonlinear stage of the MCI, which shows novel features. These include stronger drive at low cyclotron harmonics, the re-energisation of the alpha-particle population, self-modulation of the phase shift between the electrostatic and electromagnetic components, and coupling between low and high frequency modes of the excited electromagnetic field.

  12. Development of a PET cyclotron based irradiation setup for proton radiobiology

    NASA Astrophysics Data System (ADS)

    Ghithan, Sharif; Crespo, Paulo; do Carmo, S. J. C.; Ferreira Marques, Rui; Fraga, F. A. F.; Simões, Hugo; Alves, Francisco; Rachinhas, P. J. B. M.

    2015-02-01

    An out-of-yoke irradiation setup using the proton beam from a cyclotron that ordinary produces radioisotopes for positron emission tomography (PET) has been developed, characterized, calibrated and validated. The current from a 20 μm thick aluminum transmission foil is readout by home-made transimpedance electronics, providing online dose information. The main monitoring variables, delivered in real-time, include beam current, integrated charge and dose rate. Hence the dose and integrated current delivered at a given instant to an experimental setup can be computer-controlled with a shutter. In this work, we report on experimental results and Geant4 simulations of a setup which exploits for the first time the 18 MeV proton beam from a PET cyclotron to irradiate a selected region of a target using the developed irradiation system. By using this system, we are able to deliver a homogeneous beam on targets with 18 mm diameter, allowing to achieve the controlled irradiation of cell cultures located in biological multi-well dishes of 16 mm diameter. We found that the magnetic field applied inside the cyclotron plays a major role for achieving the referred to homogeneity. The quasi-Gaussian curve obtained by scanning the magnet current and measuring the corresponding dose rate must be measured before any irradiation procedure, with the shutter closed. At the optimum magnet current, which corresponds to the center of the Gaussian, a homogenous dose is observed over the whole target area. Making use of a rotating disk with a slit of 0.5 mm at a radius of 150 mm, we could measure dose rates on target ranging from 500 mGy/s down to 5 mGy/s. For validating the developed irradiation setup, several Gafchromic® EBT2 films were exposed to different values of dose. The absolute dose in the irradiated films were assessed in the 2D film dosimetry system of the Department of Radiotherapy of Coimbra University Hospital Center with a precision better than 2%. In the future, we plan to irradiate small animals, cell cultures, or other materials or samples.

  13. The efficient production of high specific activity copper-64 using a biomedial cyclotron

    SciTech Connect

    McCarthy, D.W.; Shefer, R.E.; Klinkowstein, R.E.; Bass, L.A.

    1996-05-01

    We have developed a method for the efficient and cost-effective production of high specific activity Cu-64, via the Ni-64(p,n)Cu-64 reaction, using a small biomedical cyclotron. Nickel-64 (95% enriched) has been successfully electroplated on gold disks at thicknesses of {approximately}20-300 {mu}ms and bombarded with protons at beam currents up to {approximately}45 microamps. An automated target has been designed to facilitate the irradiations on a biomedical cyclotron. Techniques have been developed for the rapid and efficient separation of Cu-64 from Ni-64 and other reaction byproducts using ion exchange chromatography. An initial production run using 55 mg of 95% enriched Ni-64 yielded 20 GBq of Cu-64 with specific activity of 4.5 GBq/{mu}g (determined by serial dilution titrations with TETA). In a series of experiments, bombardment of 18.7-23.7 mg of 85% enriched Ni-64 has produced 8.9-18.5 GBq of Cu-64 with specific activity of 4.5 GBq/{mu}g (determined by serial dilution titrations with TETA). In a series of experiments, bombardment of 18.7-23.7 mg of 85% enriched Ni-64 has produced 8.9-18.5 GBq of Cu-64 (133 {plus_minus} 10 MBq/{mu}Ahr) with specific activity of 3.5 GBq-11.5 GBq/{mu}g. The amount and specific activity of the Cu-64 produced is more than adequate for both PET and therapy experiments. The Cu-64 produced in more than adequate for both PET and therapy experiments. The Cu-64 had been used to radiolabel PTSM (pyruvaldehyde bis (N4-methylthiosemicarbazone)-used to quantify blood flow), a monoclonal antibody (1A3) and octreotide. An efficient technique for recycling the costly enriched nickel-64 target material has been developed. Nickel eluted off the separation column is collected, boiled to dryness and redissolved in the electroplating bath. Using this method, 94.2 {plus_minus} 3.2% of the Ni-64 has been recovered. The technique described provides a simple, cost-effective method for the cyclotron production of Cu-64.

  14. Electromagnetic cyclotron waves in the solar wind: Wind observation and wave dispersion analysis

    NASA Astrophysics Data System (ADS)

    Jian, L. K.; Moya, P. S.; Viñas, A. F.; Stevens, M.

    2016-03-01

    Wind observed long-lasting electromagnetic cyclotron waves near the proton cyclotron frequency on 11 March 2005, in the descending part of a fast wind stream. Bi-Maxwellian velocity distributions are fitted for core protons, beam protons, and α-particles. Using the fitted plasma parameters we conduct kinetic linear dispersion analysis and find ion cyclotron and/or firehose instabilities grow in six of 10 wave intervals. After Doppler shift, some of the waves have frequency and polarization consistent with observation, thus may be correspondence to the cyclotron waves observed.

  15. Low energy cyclotron production of multivalent transition metals for PET imaging and therapy

    NASA Astrophysics Data System (ADS)

    Avila-Rodriguez, Miguel Angel

    Recent advances in high-resolution tomographs for small animals require the production of nonconventional long-lived positron emitters to label novel radiopharmaceuticals for PET-based molecular imaging. Radioisotopes with an appropriate half life to match the kinetics of slow biological processes will allow to researchers to study the phamacokinetics of PET ligands over several hours, or even days, on the same animal, with the injection of a single dose. In addition, radionuclides with a suitable half life can potentially be distributed from a central production site making them available in PET facilities that lack an in-house cyclotron. In the last few years there has been a growing interest in the use of PET ligands labeled with radiometals, particularly isotopes of copper, yttrium and zirconium. Future clinical applications of these tracers will require them to be produced reliably and efficiently. This thesis work deals with implementing and optimizing the production of the multivalent transition metals 61,64Cu, 86Y and 89Zr for molecular PET imaging and therapy. Our findings in the production of these radionuclides at high specific activity on an 11 MeV proton-only cyclotron are presented. Local applications of these tracers, including Cu-ATSM for in vivo quantification of hypoxia, synthesis of targeted radiopharmaceuticals using activated esters of DOTA, and a novel development of positron emitting resin microspheres, are also be discussed. As a result of this thesis work, metallic radionuclides are now efficiently produced on a weekly basis in sufficient quality and quantity for collaborating scientists at UW-Madison and external users in other Universities across the country.

  16. Microwave-Excited Microplasma Thrusters Using Surface Wave and Electron Cyclotron Resonance Discharges

    NASA Astrophysics Data System (ADS)

    Mori, Daisuke; Kawanabe, Tetsuo; Takao, Yoshinori; Eriguchi, Koji; Ono, Kouichi

    2012-10-01

    Downsizing spacecrafts has recently been focused on to decrease mission costs and to increase launch rates, and missions with small satellites would bring a great advantage of reducing their risks. Such a concept supports a new approach to developing precise, reliable, and low-cost micropropulsion systems. We have studied two types of microwave-excited microplasma thrusters, using surface wave-excited and electron cyclotron resonance-excited discharges. Microwaves of S-band (4 GHz) and X-band (11 GHz) were employed to excite the plasma in these experiments, with the feed or propellant gases of Ar and He. A microplasma thruster of electrothermal type consisted of a surface wave-excited microplasma source, and a converging-diverging micronozzle to obtain the thrust. For 11-GHz microwaves at a power of 6 W, a thrust of 1.1 mN and a specific impulse of 90 s were obtained at an Ar gas flow rate of 40 sccm, where the plasma electron density was 1.2x10^20 m-3, and the gas temperature was 1.5x10^3 K; under the same conditions for 4-GHz microwaves, the thrust, specific impulse, electron density, and gas temperature were 0.93 mN, 80 s, 7.0x10^19 m-3, and 8.0x10^2 K, respectively. A microplasma thruster of electromagnetic type had a microplasma source excited by electron cyclotron resonance with external magnetic fields, to obtain the thrust through accelerating ions by ambipolar electric fields. Optical emission spectrum was dominated by Ar^+ ion lines in the microplasma thruster of electromagnetic type, owing to higher electron temperatures at lower feed-gas pressures.

  17. 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.

  18. Emergency Medical Service (EMS): Rotorcraft Technology Workshop

    NASA Technical Reports Server (NTRS)

    Bauchspies, J. S.; Adams, R. J.

    1981-01-01

    A lead organization on the national level should be designated to establish concepts, locations, and the number of shock trauma air medical services. Medical specialists desire a vehicle which incorporates advances in medical technology trends in health care. Key technology needs for the emergency medical services helicopter of the future include the riding quality of fixed wing aircraft (reduced noise and vibration), no tail rotor, small rotor, small rotor diameter, improved visibility, crashworthy vehicle, IFR capability, more affordability high reliability, fuel efficient, and specialized cabins to hold medical/diagnostic and communications equipment. Approaches to a national emergency medical service are discussed.

  19. Phase space characterization of an internal ion source for cyclotrons

    NASA Astrophysics Data System (ADS)

    Forringer, Edward Russell

    Orbit tracking codes are used to predict the behavior of the beam in a cyclotron before the cyclotron is constructed by tracking many orbits which collectively are intended to represent the beam. Cyclotrons with internal ion sources (such as the series of 250 MeV proton beam cancer therapy cyclotrons being manufactured by ACCEL Instruments GmbH of Bergisch-Gladbach Germany) present difficulty for these orbit tracking calculations in that there are several parameters which can be adjusted in the calculation that have a large effect on the phase space characteristics of the calculated beam (both the emittance of the beam and the shape of the beam in phase space). The primary goals of the research presented in this dissertation then are to experimentally measure the axial and radial emittance and luminosity of the beam produced by a cold cathode PIG (Penning Ion Gage) internal ion source under do extraction and to develop a "recipe" for initial conditions of calculated orbits starting from the ion source that match the experimentally measured beam. The experimental results presented in this dissertation, to the best of our knowledge, represent the first published emittance and luminosity measurement of a cold cathode PIG internal ion source. By taking measurements in several different con figurations, it was determined that the shape and size of the source aperture has a large effect on the characteristics of the extracted beam. We were also able to observe that increasing the plasma arc current in the ion source produces higher current and luminosity in the extracted beam. The maximum luminosity measured using a chimney with a 5.0 mm (0.196″) tall, 0.25 mm (0.010″) wide slit, was 7.1 Acm2-sr . Two other chimneys with larger apertures were measured at lower arc currents being limited by the power handling capabilities of the Ion Source Test Stand. The concepts of 'plasma boundary' and 'plasma temperature' are developed as a useful set of parameters for describing the initial conditions used in orbit tracking. We observe that an approximately flat plasma boundary provides the best match to the experimental beams emerging from the 'slit' style chimneys in our study, while a concave plasma boundary (curving toward the source axis) provides a better match for the beam that emerges from the 'hole' style chimney. In all cases, the plasma temperature that provides the best match for experimental beams is approximately 35,000 K (resulting in a central starting energy of 4.5 eV). Using the methods presented in this dissertation, the orbit tracking code Z3CYCLONE is able to predict the beam produced by a cold cathode PIG ion source with adequate accuracy such that construction of actual cyclotrons can proceed with reasonably prudent confidence that the cyclotron will perform as predicted.

  20. Medication reviews.

    PubMed

    Blenkinsopp, Alison; Bond, Christine; Raynor, David K

    2012-10-01

    Recent years have seen a formalization of medication review by pharmacists in all settings of care. This article describes the different types of medication review provided in primary care in the UK National Health Service (NHS), summarizes the evidence of effectiveness and considers how such reviews might develop in the future. Medication review is, at heart, a diagnostic intervention which aims to identify problems for action by the prescriber, the clinician conducting the review, the patient or all three but can also be regarded as an educational intervention to support patient knowledge and adherence. There is good evidence that medication review improves process outcomes of prescribing including reduced polypharmacy, use of more appropriate medicines formulation and more appropriate choice of medicine. When 'harder' outcome measures have been included, such as hospitalizations or mortality in elderly patients, available evidence indicates that whilst interventions could improve knowledge and adherence they did not reduce mortality or hospital admissions with one study showing an increase in hospital admissions. Robust health economic studies of medication reviews remain rare. However a review of cost-effectiveness analyses of medication reviews found no studies in which the cost of the intervention was greater than the benefit. The value of medication reviews is now generally accepted despite lack of robust research evidence consistently demonstrating cost or clinical effectiveness compared with traditional care. Medication reviews can be more effectively deployed in the future by targeting, multi-professional involvement and paying greater attention to medicines which could be safely stopped. PMID:22607195

  1. Cyclotron maser and plasma wave growth in magnetic loops

    NASA Technical Reports Server (NTRS)

    Hamilton, Russell J.; Petrosian, Vahe

    1990-01-01

    Cyclotron maser and plasma wave growth which results from electrons accelerated in magnetic loops are studied. The evolution of the accelerated electron distribution is determined by solving the kinetic equation including Coulomb collisions and magnetic convergence. It is found that for modest values of the column depth of the loop the growth rates of instabilities are significantly reduced and that the reduction is much larger for the cyclotron modes than for the plasma wave modes. The large decrease in the growth rate with column depth suggests that solar coronal densities must be much lower than commonly accepted in order for the cyclotron maser to operate. The density depletion has to be similar to that which occurs during auroral kilometric radiation events in the magnetosphere. The resulting distributions are much more complicated than the idealized distributions used in many theoretical studies, but the fastest growing mode can still simply be determined by the ratio of electron plasma to gyrofrequency, U=omega(sub p)/Omega(sub e). However, the dominant modes are different than for the idealized situations with growth of the z-mode largest for U approximately less than 0.5, and second harmonic x-mode (s=2) or fundamental o-mode (s=1) the dominant modes for 0.5 approximately less than U approximately less than 1. The electron distributions typically contain more than one inverted feature which could give rise to wave growth. It is shown that this can result in simultaneous amplification of more than one mode with each mode driven by a different feature and can be observed, for example, by differences in the rise times of the right and left circularly polarized components of the associated spike bursts.

  2. Electromagnetic Waves near the Proton Cyclotron Frequency: STEREO Observations

    NASA Astrophysics Data System (ADS)

    Jian, L. K.; Wei, H. Y.; Russell, C. T.; Luhmann, J. G.; Klecker, B.; Omidi, N.; Isenberg, P. A.; Goldstein, M. L.; Figueroa-Viñas, A.; Blanco-Cano, X.

    2014-05-01

    Transverse, near-circularly polarized, parallel-propagating electromagnetic waves around the proton cyclotron frequency were found sporadically in the solar wind throughout the inner heliosphere. They could play an important role in heating and accelerating the solar wind. These low-frequency waves (LFWs) are intermittent but often occur in prolonged bursts lasting over 10 minutes, named "LFW storms." Through a comprehensive survey of them from Solar Terrestrial Relations Observatory A using dynamic spectral wave analysis, we have identified 241 LFW storms in 2008, present 0.9% of the time. They are left-hand (LH) or right-hand (RH) polarized in the spacecraft frame with similar characteristics, probably due to Doppler shift of the same type of waves or waves of intrinsically different polarities. In rare cases, the opposite polarities are observed closely in time or even simultaneously. Having ruled out interplanetary coronal mass ejections, shocks, energetic particles, comets, planets, and interstellar ions as LFW sources, we discuss the remaining generation scenarios: LH ion cyclotron instability driven by greater perpendicular temperature than parallel temperature or by ring-beam distribution, and RH ion fire hose instability driven by inverse temperature anisotropy or by cool ion beams. The investigation of solar wind conditions is compromised by the bias of the one-dimensional Maxwellian fit used for plasma data calibration. However, the LFW storms are preferentially detected in rarefaction regions following fast winds and when the magnetic field is radial. This preference may be related to the ion cyclotron anisotropy instability in fast wind and the minimum in damping along the radial field.

  3. Electromagnetic waves near the proton cyclotron frequency: Stereo observations

    SciTech Connect

    Jian, L. K.; Wei, H. Y.; Russell, C. T.; Luhmann, J. G.; Klecker, B.; Omidi, N.; Isenberg, P. A.; Goldstein, M. L.; Figueroa-Viñas, A.; Blanco-Cano, X.

    2014-05-10

    Transverse, near-circularly polarized, parallel-propagating electromagnetic waves around the proton cyclotron frequency were found sporadically in the solar wind throughout the inner heliosphere. They could play an important role in heating and accelerating the solar wind. These low-frequency waves (LFWs) are intermittent but often occur in prolonged bursts lasting over 10 minutes, named 'LFW storms'. Through a comprehensive survey of them from Solar Terrestrial Relations Observatory A using dynamic spectral wave analysis, we have identified 241 LFW storms in 2008, present 0.9% of the time. They are left-hand (LH) or right-hand (RH) polarized in the spacecraft frame with similar characteristics, probably due to Doppler shift of the same type of waves or waves of intrinsically different polarities. In rare cases, the opposite polarities are observed closely in time or even simultaneously. Having ruled out interplanetary coronal mass ejections, shocks, energetic particles, comets, planets, and interstellar ions as LFW sources, we discuss the remaining generation scenarios: LH ion cyclotron instability driven by greater perpendicular temperature than parallel temperature or by ring-beam distribution, and RH ion fire hose instability driven by inverse temperature anisotropy or by cool ion beams. The investigation of solar wind conditions is compromised by the bias of the one-dimensional Maxwellian fit used for plasma data calibration. However, the LFW storms are preferentially detected in rarefaction regions following fast winds and when the magnetic field is radial. This preference may be related to the ion cyclotron anisotropy instability in fast wind and the minimum in damping along the radial field.

  4. Superthermal electron distribution measurements from polarized electron cyclotron emission

    SciTech Connect

    Luce, T.C.; Efthimion, P.C.; Fisch, N.J.

    1988-06-01

    Measurements of the superthermal electron distribution can be made by observing the polarized electron cyclotron emission. The emission is viewed along a constant magnetic field surface. This simplifies the resonance condition and gives a direct correlation between emission frequency and kinetic energy of the emitting electron. A transformation technique is formulated which determines the anisotropy of the distribution and number density of superthermals at each energy measured. The steady-state distribution during lower hybrid current drive and examples of the superthermal dynamics as the runaway conditions is varied are presented for discharges in the PLT tokamak. 15 refs., 8 figs.

  5. Analysis of a cyclotron maser instability in cylindrical geometry

    SciTech Connect

    Vorgul, I.; Cairns, R.A.; Bingham, R.

    2005-12-15

    Cyclotron maser instability is known to be one of the main mechanisms of coherent radio emission in space and laboratory plasmas. This paper investigates a particular case of such an instability induced by a horseshoe- or crescent-shaped electron velocity distribution function, which is produced when an electron beam propagates in a convergent magnetic field, whether it is Earth's magnetic field or one introduced in a laboratory experiment. The instability is analyzed in cylindrical geometry which is relevant to auroral kilometric radiation and to a laboratory experiment. Exact modeling of TE and TM anisotropic modes for circular electronic beam shows its high growth rate for modes with almost perpendicular propagation.

  6. Potential applications of an electron cyclotron resonance multicusp plasma source

    SciTech Connect

    Tsai, C.C.; Berry, L.A.; Gorbatkin, S.M.; Haselton, H.H.; Roberto, J.B.; Stirling, W.L.

    1989-01-01

    An electron cyclotron resonance (ECR) multicusp plasmatron has been developed by feeding a multicusp bucket arc chamber with a compact ECR plasma source. This novel source produced large (about 25-cm-diam), uniform (to within {plus minus}10%), dense (>10{sup 11}-cm{sup -3}) plasmas of argon, helium, hydrogen, and oxygen. It has been operated to produce an oxygen plasma for etching 12.7-cm (5-in.) positive photoresist-coated silicon wafers with uniformity within {plus minus}8%. Results and potential applications of this new ECR plasma source for plasma processing of thin films are discussed. 21 refs., 10 figs.

  7. Alcator C vertical viewing electron cyclotron emission diagnostic

    SciTech Connect

    Kato, K.; Hutchinson, I.H.

    1986-03-01

    Electron cyclotron emission measured vertically through the center of a tokamak plasma yields detailed information about the electron velocity distribution. A diagnostic developed for this purpose on Alcator C tokamak uses specialized focusing optics to obtain a well collimated viewing chord, a compact viewing dump made of pyrex or Macor to reduce the effects of wall reflection and depolarization, and a rapid-scan polarizing Michelson interferometer - InSb detector system for the spectrum measurement; all constrained by the limited access and the compact size of Alcator C. Results of diffraction analysis are used to evaluate the theoretical performance of the optical system.

  8. Alcator C vertical viewing electron cyclotron emission diagnostic

    SciTech Connect

    Kato, K.; Hutchinson, I.H.

    1986-08-01

    Electron cyclotron emission measured vertically through the center of a tokamak plasma yields detailed information about the electron velocity distribution. A diagnostic developed for this purpose on Alcator C tokamak uses specialized focusing optics to obtain a well-collimated viewing chord, a compact viewing dump made of Pyrex or Macor to reduce the effects of wall reflection and depolarization, and a rapid-scan polarizing Michelson interferometer InSb detector system for the spectrum measurement; all constrained by the limited access and the compact size of Alcator C. Results of diffraction analysis are used to evaluate the theoretical performance of the optical system.

  9. 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.

  10. Ion cyclotron resonance heating for the plasma separation process

    NASA Astrophysics Data System (ADS)

    Compant La Fontaine, A.

    1994-10-01

    The selective heating near the ion cyclotron resonance (ICR) in order to separate isotopes by the plasma separation process is investigated both experimentally and theoretically on the ERIC device. The electromagnetic field induced by a half-turn heliocoidal antenna is calculated for a uniform hot and collisional plasma. The axial wave number kz spectrum of the rotating electric field E+ exhibit the presence of two waves which characteristics determine the heating. The motion equation of the ions is resolved in the approximation of the guiding center hypothesis, so that the final heating can be directly obtained; also the comparison with the experiment is satisfactory.

  11. New Electrodeless Light Source Intensified by Electron Cyclotron Resonance Heating

    NASA Astrophysics Data System (ADS)

    Zhang, Rui; Kanno, Masato; Nishida, Yasushi; Yugami, Noboru

    1998-03-01

    Brighter and electrodeless light sources are developed by introducing the electron cyclotron resonance (ECR) effect into the discharge area. In the present proof-of-principle demonstration, a microwave source with a frequency of 2.45 GHz, and a maximum power of 1 kW is used. A mercury lamp placed inside the microwave cavity is immersed in a uniform magnetic field, B. At B = 875 G, which satisfies the ECR condition, the light intensity is increased by 28% at an incident microwave power of 800 W. Short-wavelength components are effectively improved relative to long ones.

  12. RF physics of ICWC discharge at high cyclotron harmonics

    SciTech Connect

    Lyssoivan, A.; Van Eester, D.; Wauters, T.; Vervier, M.; Van Schoor, M.; Bobkov, V.; Rohde, V.; Schneider, P.; Douai, D.; Kogut, D.; Kreter, A.; Möller, S.; Philipps, V.; Sergienko, G.; Moiseenko, V.; Noterdaeme, J.-M.; Collaboration: TEXTOR Team; ASDEX Upgrade Team

    2014-02-12

    Recent experiments on Ion Cyclotron Wall Conditioning (ICWC) performed in tokamaks TEXTOR and ASDEX Upgrade with standard ICRF antennas operated at fixed frequencies but variable toroidal magnetic field demonstrated rather contrasting parameters of ICWC discharge in scenarios with on-axis fundamental ion cyclotron resonance (ICR) for protons,ω=ω{sub H+}, and with its high cyclotron harmonics (HCH), ω=10ω{sub cH+}⋅ HCH scenario: very high antenna coupling to low density RF plasmas (P{sub pl}≈0.9P{sub RF-G}) and low energy Maxwellian distribution of CX hydrogen atoms with temperature T{sub H}≈350 eV. Fundamental ICR: lower antenna-plasma coupling efficiency (by factor of about 1.5 times) and generation of high energy non-Maxwellian CX hydrogen atoms (with local energy E{sub ⊥H} ≥1.0 keV). In the present paper, we analyze the obtained experimental results numerically using (i) newly developed 0-D transport code describing the process of plasma production with electron and ion collisional ionization in helium-hydrogen gas mixture and (ii) earlier developed 1-D Dispersion Relation Solver accounting for finite temperature effects and collision absorption mechanisms for all plasma species in addition to conventionally examined Landau/TTPM damping for electrons and cyclotron absorption for ions. The numerical study of plasma production in helium with minor hydrogen content in low and high toroidal magnetic fields is presented. The investigation of the excitation, conversion and absorption of plasma waves as function of B{sub T}-field suggests that only fast waves (FW) may give a crucial impact on antenna coupling and characteristics of the ICWC discharge using standard poloidally polarized ICRF antennas designed to couple RF power mainly to FW. The collisional (non-resonant) absorption by electrons and ions and IC absorption by resonant ions of minor concentration in low T{sub e} plasmas is studied at fundamental ICR and its high harmonics.

  13. A compact accelerating structure for stacked isochronous cyclotrons

    NASA Astrophysics Data System (ADS)

    Meitzler, C. R.; Byeon, J.; McIntyre, P. M.; Rogers, Bob; Sattarov, A.

    2003-03-01

    An accelerator-driven thorium cycle power reactor is being developed, based on a flux-coupled stack of isochronous cyclotrons. (IC) The stack consists of seven independent accelerators (total beam power 15 MW at 1 GeV), stacked on a spacing ˜ 20 cm. The close spacing poses unique problems for the design of the accelerating cavities. We have invented a 4-bar RF dipole structure for the purpose. We have built a cold model and are studying its operating characteristics. The structure will be described. We present measurements of the resonant frequency, parasitic capacitances, and electric and magnetic field distributions in the structure.

  14. Cyclotron production of Ac-225 for targeted alpha therapy.

    PubMed

    Apostolidis, C; Molinet, R; McGinley, J; Abbas, K; Möllenbeck, J; Morgenstern, A

    2005-03-01

    The feasibility of producing Ac-225 by proton irradiation of Ra-226 in a cyclotron through the reaction Ra-226(p,2n)Ac-225 has been experimentally demonstrated for the first time. Proton energies were varied from 8.8 to 24.8 MeV and cross-sections were determined by radiochemical analysis of reaction yields. Maximum yields were reached at incident proton energies of 16.8 MeV. Radiochemical separation of Ac-225 from the irradiated target yielded a product suitable for targeted alpha therapy of cancer. PMID:15607913

  15. A new EMIS facility at the Tohoku University cyclotron

    NASA Astrophysics Data System (ADS)

    Fujioka, M.; Shinozuka, T.; Tanaka, E.; Arai, Y.; Hayashibe, S.; Ishimatsu, T.

    An EMIS facility has begun operation at one of the beam lines of a multipurpose cyclotron of K = 50 MeV. The separator is of a Scandinavian type of 55° deflection and 1500 mm dispersion, and is equipped with three beam-transport lines to which are connected a tape-transport system for ISOL study, a retardation system for implantation work and an optical spectrometer for surface analysis. The status and developments of this facility are reported here for the first time.

  16. Numerical model of electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Mironov, V.; Bogomolov, S.; Bondarchenko, A.; Efremov, A.; Loginov, V.

    2015-12-01

    Important features of the electron cyclotron resonance ion source (ECRIS) operation are accurately reproduced with a numerical code. The code uses the particle-in-cell technique to model the dynamics of ions in ECRIS plasma. It is shown that a gas dynamical ion confinement mechanism is sufficient to provide the ion production rates in ECRIS close to the experimentally observed values. Extracted ion currents are calculated and compared to the experiment for a few sources. Changes in the simulated extracted ion currents are obtained with varying the gas flow into the source chamber and the microwave power. Empirical scaling laws for ECRIS design are studied and the underlying physical effects are discussed.

  17. Experimental demonstration of high efficiency electron cyclotron autoresonance acceleration

    SciTech Connect

    LaPointe, M.A.; Yoder, R.B.; Wang, C.; Ganguly, A.K.; Hirshfield, J.L.

    1996-04-01

    First experimental results are reported on the operation of a multimegawatt 2.856 GHz cyclotron autoresonance accelerator (CARA). A 90{endash}100 kV, 2{endash}3 MW linear electron beam has had up to6.6 MW added to it in CARA, with an rf-to-beam power efficiency of up to 96{percent}. This efficiency level is larger than that reported for any fast-wave interaction between radiation and electrons, and also larger than that in normal conducting rf linear accelerators. The results obtained are in good agreement with theoretical predictions. {copyright} {ital 1996 The American Physical Society.}

  18. Electron cyclotron resonance microwave ion sources for thin film processing

    SciTech Connect

    Berry, L.A.; Gorbatkin, S.M.

    1990-01-01

    Plasmas created by microwave absorption at the electron cyclotron resonance (ECR) are increasingly used for a variety of plasma processes, including both etching and deposition. ECR sources efficiently couple energy to electrons and use magnetic confinement to maximize the probability of an electron creating an ion or free radical in pressure regimes where the mean free path for ionization is comparable to the ECR source dimensions. The general operating principles of ECR sources are discussed with special emphasis on their use for thin film etching. Data on source performance during Cl base etching of Si using an ECR system are presented. 32 refs., 5 figs.

  19. Fast particle-driven ion cyclotron emission (ICE) in tokamak plasmas and the case for an ICE diagnostic in ITER

    NASA Astrophysics Data System (ADS)

    McClements, K. G.; D'Inca, R.; Dendy, R. O.; Carbajal, L.; Chapman, S. C.; Cook, J. W. S.; Harvey, R. W.; Heidbrink, W. W.; Pinches, S. D.

    2015-04-01

    The detection of fast particle-driven waves in the ion cyclotron frequency range (ion cyclotron emission or ICE) could provide a passive, non-invasive diagnostic of confined and escaping fast particles (fusion α-particles and beam ions) in ITER, and would be compatible with the high radiation environment of deuterium-tritium plasmas in that device. Recent experimental results from ASDEX Upgrade and DIII-D demonstrate the efficacy of ICE as a diagnostic of different fast ion species and of fast ion losses, while recent particle-in-cell (PIC) and hybrid simulations provide a more exact comparison with measured ICE spectra and open the prospect of exploiting ICE more fully as a fast ion diagnostic in future experiments. In particular the PIC/hybrid approach should soon make it possible to simulate the nonlinear physics of ICE in full toroidal geometry. Emission has been observed previously at a wide range of poloidal angles, so there is flexibility in the location of ICE detectors. Such a detector could be implemented in ITER by installing a small toroidally orientated loop near the plasma edge or by adding a detection capability to the ion cyclotron resonance heating (ICRH) antennae. In the latter case, the antenna could be used simultaneously to heat the plasma and detect ICE, provided that frequencies close to those of the ICRH source are strongly attenuated in the detection system using a suitable filter. Wavenumber information, providing additional constraints on the fast ion distribution exciting the emission, could be obtained by measuring ICE using a toroidally distributed array of detectors or different straps of the ICRH antenna.

  20. Current drive with fast waves, electron cyclotron waves, and neutral injection in the DIII-D tokamak

    SciTech Connect

    Prater, R.; Petty, C.C.; Pinsker, R.I.; Chiu, S.C.; deGrassie, J.S.; Harvey, R.W.; Ikel, H.; Lin-Liu, Y.R.; Luce, T.C. ); James, R.A. ); Porkolab, M. ); Baity, F.W.; Goulding, R.H.; Hoffmann, D.J. ); Kawash

    1992-09-01

    Current drive experiments have been performed on the DIII-D tokamak using fast waves, electron cyclotron waves, and neutral injection. Fast wave experiments were performed using a 4-strap antenna with 1 MW of power at 60 MHz. These experiments showed effective heating of electrons, with a global heating efficiency equivalent to that of neutral injection even when the single pass damping was calculated to be as small as 5%. The damping was probably due to the effect of multiple passes of the wave through the plasma. Fast wave current drive experiments were performed with a toroidally directional phasing of the antenna straps. Currents driven by fast wave current drive (FWCD) in the direction of the main plasma current of up to 100 kA were found, not including a calculated 40 kA of bootstrap current. Experiments with FWCD in the counter current direction showed little current drive. In both cases, changes in the sawtooth behavior and the internal inductance qualitatively support the measurement of FWCD. Experiments on electron cyclotron current drive have shown that 100 kA of current can be driven by 1 MW of power at 60 GHz. Calculations with a Fokker-Planck code show that electron cyclotron current drive (ECCD) can be well predicted when the effects of electron trapping and of the residual electric field are included. Experiments on driving current with neutral injection showed that effective current drive could be obtained and discharges with full current drive were demonstrated. Interestingly, all of these methods of current drive had about the same efficiency, 0.015 {times} 10{sup 20} MA/MW/m{sup 2}.

  1. The Upgrade Project at Texas A and M University Cyclotron Institute: Update

    SciTech Connect

    Tabacaru, G.; Abegglen, F.; Chubaryan, G.; Derrig, G.; Clark, H. L.; Kim, G.; May, D.; Tribble, R. E.; Aerje, J.

    2010-11-24

    The Cyclotron Institute at Texas A and M University is currently under an upgrade process. The plan is to produce re-accelerated radioactive ion beams using the recommissioned 88'' Cyclotron as a driver and two different devices. The technique for producing radioactive species will be presented.

  2. Quantum non demolition measurement of cyclotron excitations in a Penning trap

    NASA Technical Reports Server (NTRS)

    Marzoli, Irene; Tombesi, Paolo

    1993-01-01

    The quantum non-demolition measurement of the cyclotron excitations of an electron confined in a Penning trap could be obtained by measuring the resonance frequency of the axial motion, which is coupled to the cyclotron motion through the relativistic shift of the electron mass.

  3. 76 FR 80982 - International Cyclotron, Inc., Hato Rey, Puerto Rico; Order Suspending Licensed Activities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-27

    ... radioactive material above specified amounts must provide a guarantee or other financial arrangement that... authorization to possess and use radioactive material of half-life greater than 120 days and in quantities... International Cyclotron, Inc. (International Cyclotron; Licensee) is the holder of Byproduct Materials...

  4. Sawtooth-Control Mechanism using Toroidally Propagating Ion-Cyclotron-Resonance Waves in Tokamaks

    SciTech Connect

    Graves, J. P.; Coda, S.; Chapman, I.

    2009-02-13

    The sawtooth control mechanism in plasmas employing off-axis toroidally propagating ion cyclotron resonance waves in tokamaks is reinvestigated. The radial drift excursion of energetic passing ions distributed asymmetrically in the velocity parallel to the magnetic field determines stability when the rational q=1 surface resides within a narrow region centered about the shifted fundamental cyclotron resonance.

  5. Accelerator Production of Isotopes for Medical Use

    NASA Astrophysics Data System (ADS)

    Lapi, Suzanne

    2014-03-01

    The increase in use of radioisotopes for medical imaging and therapy has led to the development of novel routes of isotope production. For example, the production and purification of longer-lived position emitting radiometals has been explored to allow for nuclear imaging agents based on peptides, antibodies and nanoparticles. These isotopes (64Cu, 89Zr, 86Y) are typically produced via irradiation of solid targets on smaller medical cyclotrons at dedicated facilities. Recently, isotope harvesting from heavy ion accelerator facilities has also been suggested. The Facility for Rare Isotope Beams (FRIB) will be a new national user facility for nuclear science to be completed in 2020. Radioisotopes could be produced by dedicated runs by primary users or may be collected synergistically from the water in cooling-loops for the primary beam dump that cycle the water at flow rates in excess of hundreds of gallons per minute. A liquid water target system for harvesting radioisotopes at the National Superconducting Cyclotron Laboratory (NSCL) was designed and constructed as the initial step in proof-of-principle experiments to harvest useful radioisotopes in this manner. This talk will provide an overview of isotope production using both dedicated machines and harvesting from larger accelerators typically used for nuclear physics. Funding from Department of Energy under DESC0007352 and DESC0006862.

  6. 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.

  7. Nonlinear theory of drift-cyclotron kinetics and the possible breakdown of gyro-kinetics

    SciTech Connect

    Waltz, R. E.; Deng Zhao

    2013-01-15

    A nonlinear theory of drift-cyclotron kinetics (termed cyclo-kinetics here) is formulated to test the breakdown of the gyro-kinetic approximations. Six dimensional cyclo-kinetics can be regarded as an extension of five dimensional gyro-kinetics to include high-frequency cyclotron waves, which can interrupt the low-frequency gyro-averaging in the (sixth velocity grid) gyro-phase angle. Nonlinear cyclo-kinetics has no limit on the amplitude of the perturbations. Formally, there is no gyro-averaging when all cyclotron (gyro-phase angle) harmonics of the perturbed distribution function (delta-f) are retained. Retaining only the (low frequency) zeroth cyclotron harmonic in cyclo-kinetics recovers both linear and nonlinear gyro-kinetics. Simple recipes are given for converting continuum nonlinear delta-f gyro-kinetic transport simulation codes to cyclo-kinetics codes by retaining (at least some) higher cyclotron harmonics.

  8. Effect of high energy electrons on H(-) production and destruction in a high current DC negative ion source for cyclotron.

    PubMed

    Onai, M; Etoh, H; Aoki, Y; Shibata, T; Mattei, S; Fujita, S; Hatayama, A; Lettry, J

    2016-02-01

    Recently, a filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In this study, numerical modeling of the filament arc-discharge source plasma has been done with kinetic modeling of electrons in the ion source plasmas by the multi-cusp arc-discharge code and zero dimensional rate equations for hydrogen molecules and negative ions. In this paper, main focus is placed on the effects of the arc-discharge power on the electron energy distribution function and the resultant H(-) production. The modelling results reasonably explains the dependence of the H(-) extraction current on the arc-discharge power in the experiments. PMID:26932009

  9. 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.

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

    NASA Astrophysics Data System (ADS)

    Braccini, Saverio

    2013-04-01

    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 ?A for radioisotope production, as well as for both pulsed and continuous beams.

  11. Electron cyclotron current drive modelling with parallel momentum correction for tokamaks and stellarators

    SciTech Connect

    Maassberg, H.; Beidler, C. D.; Marushchenko, N. B.

    2012-10-15

    The electron cyclotron current drive (ECCD) is described by the solution of a drift-kinetic equation (DKE) with the quasi-linear heating term which is highly localised in phase space. Within the adjoint approach, an equivalent DKE must be solved without this highly localised source, and the ECCD is described by a straightforward convolution in phase space. The parallel momentum correction technique [Maassberg et al., Phys. Plasmas 16, 072504 (2009)] reduces the problem to the solution of a simplified mono-energetic DKE. The mono-energetic distribution functions are calculated by the DKES code [W. I. van Rij and S. P. Hirshman, Phys. Fluids B 1, 563 (1989)]. Parallel momentum correction, requiring only an energy-dependent weighting factor, is applied to these distribution functions allowing for the direct estimation of the EC-driven current. For small yet finite collisionalities, a rather simple model for ECCD is presented. In this approach, the symmetric portion of the electron distribution function with respect to v{sub Parallel-To} (the Ware pinch contribution) is neglected and an 'off-set' only in the passing particle domain adds to the collisionless (anti-symmetric) distribution function. For this approximation, only the mono-energetic parallel conductivity coefficient as function of the collisionality is needed. The impact of small yet finite collisionalities on ECCD is shown for X2- and O2-scenarios at W7-X.

  12. Molybdenum target specifications for cyclotron production of 99mTc based on patient dose estimates.

    PubMed

    Hou, X; Tanguay, J; Buckley, K; Schaffer, P; Bénard, F; Ruth, T J; Celler, A

    2016-01-21

    In response to the recognized fragility of reactor-produced (99)Mo supply, direct production of (99m)Tc via (100)Mo(p,2n)(99m)Tc reaction using medical cyclotrons has been investigated. However, due to the existence of other Molybdenum (Mo) isotopes in the target, in parallel with (99m)Tc, other technetium (Tc) radioactive isotopes (impurities) will be produced. They will be incorporated into the labeled radiopharmaceuticals and result in increased patient dose. The isotopic composition of the target and beam energy are main factors that determine production of impurities, thus also dose increases. Therefore, they both must be considered when selecting targets for clinical (99m)Tc production. Although for any given Mo target, the patient dose can be predicted based on complicated calculations of production yields for each Tc radioisotope, it would be very difficult to reverse these calculations to specify target composition based on dosimetry considerations. In this article, a relationship between patient dosimetry and Mo target composition is studied. A simple and easy algorithm for dose estimation, based solely on the knowledge of target composition and beam energy, is described. Using this algorithm, the patient dose increase due to every Mo isotope that could be present in the target is estimated. Most importantly, a technique to determine Mo target composition thresholds that would meet any given dosimetry requirement is proposed. PMID:26683410

  13. Molybdenum target specifications for cyclotron production of 99mTc based on patient dose estimates

    NASA Astrophysics Data System (ADS)

    Hou, X.; Tanguay, J.; Buckley, K.; Schaffer, P.; Bénard, F.; Ruth, T. J.; Celler, A.

    2016-01-01

    In response to the recognized fragility of reactor-produced 99Mo supply, direct production of 99mTc via 100Mo(p,2n)99mTc reaction using medical cyclotrons has been investigated. However, due to the existence of other Molybdenum (Mo) isotopes in the target, in parallel with 99mTc, other technetium (Tc) radioactive isotopes (impurities) will be produced. They will be incorporated into the labeled radiopharmaceuticals and result in increased patient dose. The isotopic composition of the target and beam energy are main factors that determine production of impurities, thus also dose increases. Therefore, they both must be considered when selecting targets for clinical 99mTc production. Although for any given Mo target, the patient dose can be predicted based on complicated calculations of production yields for each Tc radioisotope, it would be very difficult to reverse these calculations to specify target composition based on dosimetry considerations. In this article, a relationship between patient dosimetry and Mo target composition is studied. A simple and easy algorithm for dose estimation, based solely on the knowledge of target composition and beam energy, is described. Using this algorithm, the patient dose increase due to every Mo isotope that could be present in the target is estimated. Most importantly, a technique to determine Mo target composition thresholds that would meet any given dosimetry requirement is proposed.

  14. Use of electron cyclotron resonance x-ray source for nondestructive testing application

    SciTech Connect

    Baskaran, R.; Selvakumaran, T.S.

    2006-03-15

    Electron cyclotron resonance (ECR) technique is being used for generating x rays in the low-energy region (<150 keV). Recently, the source is used for the calibration of thermoluminescent dosimetry (TLD) badges. In order to qualify the ECR x-ray source for imaging application, the source should give uniform flux over the area under study. Lead collimation arrangement is made to get uniform flux. The flux profile is measured using a teletector at different distance from the port and uniform field region of 10x10 cm{sup 2} has been marked at 20 cm from the x-ray exit port. A digital-to-analog converter (DAC) circuit pack is used for examining the source performance. The required dose for nondestructive testing examination has been estimated using a hospital x-ray machine and it is found to be 0.05 mSv. Our source experimental parameters are tuned and the DAC circuit pack was exposed for nearly 7 min to get the required dose value. The ECR x-ray source operating parameters are argon pressure: 10{sup -5} Torr, microwave power: 350 W, and coil current: 0 A. The effective energy of the x-ray spectrum is nearly 40 keV. The x-ray images obtained from ECR x-ray source and hospital medical radiography machine are compared. It is found that the image obtained from ECR x-ray source is suitable for NDT application.

  15. Long-term results of high-dose conformal radiotherapy for patients with medically inoperable T1-3N0 non-small-cell lung cancer: Is low incidence of regional failure due to incidental nodal irradiation?

    SciTech Connect

    Chen Ming; Hayman, James A.; Haken, Randall K. ten; Tatro, Daniel; Fernando, Shaneli; Kong, F.-M. . E-mail: fengkong@med.umich.edu

    2006-01-01

    Purpose: To report the results of high-dose conformal irradiation and examine incidental nodal irradiation and nodal failure in patients with inoperable early-stage non-small-cell lung cancer (NSCLC). Methods and Materials: This analysis included patients with inoperable CT-staged T1-3N0M0 NSCLC treated on our prospective dose-escalation trial. Patients were treated with radiation alone (total dose, 63-102.9 Gy in 2.1-Gy daily fractions) with a three-dimensional conformal technique without intentional nodal irradiation. Bilateral highest mediastinal and upper/lower paratracheal, prevascular and retrotracheal, sub- and para-aortic, subcarinal, paraesophageal, and ipsilateral hilar regions were delineated individually. Nodal failure and doses of incidental irradiation were studied. Results: The potential median follow-up was 104 months. For patients who completed protocol treatment, median survival was 31 months. The actuarial overall survival rate was 86%, 61%, 43%, and 21% and the cause-specific survival rate was 89%, 70%, 53%, and 35% at 1, 2, 3, and 5 years, respectively. Weight loss (p = 0.008) and radiation dose in Gy (p = 0.013) were significantly associated with overall survival. In only 22% and 13% of patients examined did ipsilateral hilar and paratracheal (and subaortic for left-sided tumor) nodal regions receive a dose of {>=}40 Gy, respectively. Less than 10% of all other nodal regions received a dose of {>=}40 Gy. No patients failed initially at nodal sites. Conclusions: Radiation dose is positively associated with overall survival in patients with medically inoperable T1-3N0 NSCLC, though long-term results remain poor. The nodal failure rate is low and does not seem to be due to high-dose incidental irradiation.

  16. High-Dose Hypofractionated Proton Beam Radiation Therapy Is Safe and Effective for Central and Peripheral Early-Stage Non-Small Cell Lung Cancer: Results of a 12-Year Experience at Loma Linda University Medical Center

    SciTech Connect

    Bush, David A.; Cheek, Gregory; Zaheer, Salman; Wallen, Jason; Mirshahidi, Hamid; Katerelos, Ari; Grove, Roger; Slater, Jerry D.

    2013-08-01

    Purpose: We update our previous reports on the use of hypofractionated proton beam radiation therapy for early-stage lung cancer patients. Methods and Materials: Eligible subjects had biopsy-proven non-small cell carcinoma of the lung and were medically inoperable or refused surgery. Clinical workup required staging of T1 or T2, N0, M0. Subjects received hypofractionated proton beam therapy to the primary tumor only. The dose delivered was sequentially escalated from 51 to 60 Gy, then to 70 Gy in 10 fractions over 2 weeks. Endpoints included toxicity, pulmonary function, overall survival (OS), disease-specific survival (DSS), and local control (LC). Results: One hundred eleven subjects were analyzed for treatment outcomes. The patient population had the following average characteristics; age 73.2 years, tumor size 3.6 cm, and 1.33 L forced expiratory volume in 1 second. The entire group showed improved OS with increasing dose level (51, 60, and 70 Gy) with a 4-year OS of 18%, 32%, and 51%, respectively (P=.006). Peripheral T1 tumors exhibited LC of 96%, DSS of 88%, and OS of 60% at 4 years. Patients with T2 tumors showed a trend toward improved LC and survival with the 70-Gy dose level. On multivariate analysis, larger tumor size was strongly associated with increased local recurrence and decreased survival. Central versus peripheral location did not correlate with any outcome measures. Clinical radiation pneumonitis was not found to be a significant complication, and no patient required steroid therapy after treatment for radiation pneumonitis. Pulmonary function was well maintained 1 year after treatment. Conclusions: High-dose hypofractionated proton therapy achieves excellent outcomes for lung carcinomas that are peripherally or centrally located. The 70-Gy regimen has been adopted as standard therapy for T1 tumors at our institution. Larger T2 tumors show a trend toward improved outcomes with higher doses, suggesting that better results could be seen with intensified treatment.

  17. Status of the ECR ion source at the Uppsala cyclotron

    NASA Astrophysics Data System (ADS)

    Ekström, C.; Hemryd, B.; Holm, S.; Renberg, P.-U.; Thuresson, L.; Wessman, D.; Arnesen, A.; Hallin, R.; Heijkenskjöld, F.; Nordgren, J.; Vogel, O.

    1992-04-01

    The room-temperature ECR ion source at The Svedberg Laboratory, Uppsala, is being used as injector for the Gustaf Werner cylcotron as well as for atomic-physics experiments. In November 1990 the first heavy-ion beams from the ECR ion source were accelerated in the cyclotron. Nuclear-physics experiments have now taken data using beams of He2+, O5+, and N6+. The transmission through the cyclotron is typically 5%. The present energy record is 450 MeV N6+. The energy of the heavy-ion beams will be increased further by acceleration in the CELSIUS storage ring. Examples of atomic-physics experiments in preparation are emission spectroscopy of highly ionized atoms, in particular, to study the transitions between Rydberg states, and studies of electron transfer processes in collisions of slow multicharged ions with atoms. The studies of yrast transitions are of interest in the field of x-ray lasers and one motivation for the electron transfer studies is the importance of these phenomena in astrophysics and fusion research.

  18. An Investigation of Ion Cyclotron Wave Storms at 1 AU

    NASA Astrophysics Data System (ADS)

    Jian, L.; Russell, C. T.; Vinas, A. F.; Goldstein, M. L.; Hwang, K.

    2013-12-01

    Strong narrow-band ion cyclotron waves (ICWs) are observed sporadically in the solar wind in the inner heliosphere. They are observed to be nearly circularly polarized, with magnetic perturbations transverse to the background magnetic field. The fluctuations propagate close to the direction of the background magnetic field. At times, these fluctuations appear as ICW storms lasting tens of minutes. Analysis of a one-year survey of ICW storms using STEREO A data, indicates that the distribution of ICW storms does not align with the focusing cone of interstellar neutrals and the fluctuations are unlikely to result from interaction involving the pickup of interstellar neutrals. In this study, we investigate other scenarios: local generation through ion cyclotron instability or beam instability. The Wind and Cluster spacecraft have provided high-resolution magnetic and electric field data, as well as temperature anisotropies for protons and ions. We use them to study the variation in wave parameters of ICW storms with solar wind plasma conditions. This investigation will enhance our understanding of the generation of the ICWs and their interaction with particles in the solar wind.

  19. Induced electric field by ion cyclotron wave heating

    NASA Astrophysics Data System (ADS)

    Xiang, Nong; Cary, John R.

    2012-03-01

    Ion cyclotron resonant frequency (ICRF) heating has been widely used to heat ions in fusion devices. As the ion cyclotron wave passes the (lower hybrid or hybrid) resonance, the incident electromagnetic wave converts to an electrostatic wave and the wave amplitude reaches its maximum. Meanwhile, the parametric decay may be triggered for a sufficiently large input power. Thus,the wave amplitude forms a peak near the resonance with a width of a few tens of ion gyro-radius. For typical ICRF heating parameters, it is found that the ponderomotive force induced is very significant. As a result, the ions are expelled from the region while the electrons are pulled in. Therefore an ambipolar electric field is produced. Our 1D PIC simulations show that the electric field induced could be of order of 10kV/m, comparable to the typically observed radial electric field. It is believed that the resulted electric field should be important to particle transport and plasma rotation.

  20. Vacuum system of the cyclotrons in VECC, Kolkata

    SciTech Connect

    Roy, Anindya; Bhole, R.B.; Akhtar, J.; Yadav, R.C.; Pal, Sarbajit; Sarkar, D.; Bhandari, R.K. E-mail: rbb@vecc.gov.in E-mail: yadav@vecc.gov.in E-mail: dsarkar@vecc.gov.in

    2011-07-01

    The vacuum system of the K=130 Room Temperature Cyclotron (RTC) (operational since 1978) has been recently modernized and the same of the K{sub bend}=520 Superconducting Cyclotron (SCC), currently under commissioning, is being deployed for remote monitoring and control. The vacuum system of RTC is designed to achieve and maintain vacuum level of 2 X 10{sup -6} mbar inside 23 m{sup 3} volume of Resonator tank and DEE tank. This has been upgraded by replacing several valves, Freon units, gauges and pumps. The relay based manual control system has been replaced by PLC based automated system. The SCC vacuum system also has an elaborate arrangement comprising of turbo molecular pumping modules with associated isolation valves and characteristic gauges. This paper describes essential elements, typically used to obtain high (1X10{sup -7} mbar) vacuum using rotary pumps, diffusion pumps and cold traps/turbo-molecular pumps and other system components such as valves, gauges and baffles. The supervisory control methodology/scheme of both the vacuum systems, developed in-house using EPICS (Experimental Physics and Industrial Control System), a standard open-source software tool for designing distributed control system, is also elaborated here. (author)

  1. Electron cyclotron emission measurements on the Texas Experimental Tokamak

    SciTech Connect

    Austin, M.E. Jr.

    1992-01-01

    A ten-channel grating polychromator was designed, constructed, and installed on the Texas Experimental Tokamak to monitor the second harmonic electron cyclotron emission. Electron temperature profiles were derived from measurements of the optically thick radiation for a variety of plasma confinement experiments. The radial and temporal evolution of T[sub e] has been characterized for electron cyclotron heated discharges with 150 kW of 60 GHz power. Comparisons were made of the heating efficiency of two type of ECH launchers. A focussed launcher was shown to have slightly better heating efficiency than an unfocussed launcher; however, the focussed antenna did not yield significantly higher electron temperatures as expected. A study of the time evolution of the electron temperature indicated that increased sawtooth activity limited the effectiveness of the focussed launcher. A focussing hog-horn antenna was fabricated and installed on the inboard side of the tokamak to measure emission directed towards the high-field side during ECH. Comparison of the radiation temperature profiles from low-field side and high-field side antennas indicates the creation of a nonthermal electron distribution by the heating. The results of the experiment compare favorably with theoretical predictions from a quasi-linear Fokker-Planck code of a 6 keV nonthermal population with a density about 1 percent of the thermal density.

  2. Robust Matching System for the ITER Ion Cyclotron System

    NASA Astrophysics Data System (ADS)

    Swain, D.; Goulding, R.; Rasmussen, D.; Vervier, M.; Messiaen, A.; Dumortier, P.

    2008-11-01

    The ITER ion cyclotron system is required to deliver 20 MW to the ITER plasma under a number of different operating scenarios. The EU will fabricate the antenna, the US will supply the matching system and transmission lines, and India will deliver the rf sources and high-voltage power supplies. A brief description of the complete ion cyclotron system will be presented, and different design options for the matching system will be discussed. Emphasis will be on analyzing the ability of the system to operate effectively during sudden changes caused by plasma perturbations (e. g., ELMs), and on the robustness of matching algorithms. Particular challenges are: the possibility of relatively low loading of the antenna by the plasma because of a large plasma-antenna distance; the resulting high voltages in the matching system (which must be minimized by good system design); the need to install a number of large matching components in the tight space available near the tokamak; and the requirement for operation and maintenance in a radiation environment.

  3. 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.

  4. Medical Imaging.

    ERIC Educational Resources Information Center

    Barker, M. C. J.

    1996-01-01

    Discusses four main types of medical imaging (x-ray, radionuclide, ultrasound, and magnetic resonance) and considers their relative merits. Describes important recent and possible future developments in image processing. (Author/MKR)

  5. Medical Appointments

    MedlinePlus

    ... in Reviewed April 16, 2014 Select a Language: Fact Sheet 203 Medical Appointments GETTING THE MOST FROM OFFICE ... have more questions than when they arrived. This fact sheet talks about ways to prepare for your next ...

  6. Taking Medication

    MedlinePlus Videos and Cool Tools

    ... Tracker App Tip Sheets and Handouts AADE7 Self-Care Behaviors Healthy Eating Being Active Monitoring Taking Medication ... Legislation State Legislation AADE Policy Positions & Statements Affordable Care Act Information Advocacy Tools and Resources Cart Search ...

  7. Medical Marijuana.

    PubMed

    Capriotti, Teri

    2016-01-01

    The use of medicinal marijuana is increasing. Marijuana has been shown to have therapeutic effects in certain patients, but further research is needed regarding the safety and efficacy of marijuana as a medical treatment for various conditions. A growing body of research validates the use of marijuana for a variety of healthcare problems, but there are many issues surrounding the use of this substance. This article discusses the use of medical marijuana and provides implications for home care clinicians. PMID:26645838

  8. COMPLETE SUPPRESSION OF THE M=2/N-1 NEOCLASSICAL TEARING MODE USING ELECTRON CYCLOTRON CURRENT DRIVE ON DIII-D

    SciTech Connect

    PETTY,CC; LAHAYE,LA; LUCE,TC; HUMPHREYS,DA; HYATT,AW; PRATER,R; STRAIT,EJ; WADE,MR

    2003-03-01

    A271 COMPLETE SUPPRESSION OF THE M=2/N-1 NEOCLASSICAL TEARING MODE USING ELECTRON CYCLOTRON CURRENT DRIVE ON DIII-D. The first suppression of the important and deleterious m=2/n=1 neoclassical tearing mode (NTM) is reported using electron cyclotron current drive (ECCD) to replace the ''missing'' bootstrap current in the island O-point. Experiments on the DIII-D tokamak verify the maximum shrinkage of the m=2/n=1 island occurs when the ECCD location coincides with the q = 2 surface. The DIII-D plasma control system is put into search and suppress mode to make small changes in the toroidal field to find and lock onto the optimum position, based on real time measurements of dB{sub {theta}}/dt, for complete m=2/n=1 NTM suppression by ECCD. The requirements on the ECCD for complete island suppression are well modeled by the modified Rutherford equation for the DIII-D plasma conditions.

  9. Electron cyclotron resonance ion source plasma characterization by X-ray spectroscopy and X-ray imaging

    NASA Astrophysics Data System (ADS)

    Mascali, David; Castro, Giuseppe; Biri, Sándor; Rácz, Richárd; Pálinkás, József; Caliri, Claudia; Celona, Luigi; Neri, Lorenzo; Romano, Francesco Paolo; Torrisi, Giuseppe; Gammino, Santo

    2016-02-01

    An experimental campaign aiming to investigate electron cyclotron resonance (ECR) plasma X-ray emission has been recently carried out at the ECRISs—Electron Cyclotron Resonance Ion Sources laboratory of Atomki based on a collaboration between the Debrecen and Catania ECR teams. In a first series, the X-ray spectroscopy was performed through silicon drift detectors and high purity germanium detectors, characterizing the volumetric plasma emission. The on-purpose developed collimation system was suitable for direct plasma density evaluation, performed "on-line" during beam extraction and charge state distribution characterization. A campaign for correlating the plasma density and temperature with the output charge states and the beam intensity for different pumping wave frequencies, different magnetic field profiles, and single-gas/gas-mixing configurations was carried out. The results reveal a surprisingly very good agreement between warm-electron density fluctuations, output beam currents, and the calculated electromagnetic modal density of the plasma chamber. A charge-coupled device camera coupled to a small pin-hole allowing X-ray imaging was installed and numerous X-ray photos were taken in order to study the peculiarities of the ECRIS plasma structure.

  10. Electron cyclotron resonance ion source plasma characterization by X-ray spectroscopy and X-ray imaging.

    PubMed

    Mascali, David; Castro, Giuseppe; Biri, Sándor; Rácz, Richárd; Pálinkás, József; Caliri, Claudia; Celona, Luigi; Neri, Lorenzo; Romano, Francesco Paolo; Torrisi, Giuseppe; Gammino, Santo

    2016-02-01

    An experimental campaign aiming to investigate electron cyclotron resonance (ECR) plasma X-ray emission has been recently carried out at the ECRISs-Electron Cyclotron Resonance Ion Sources laboratory of Atomki based on a collaboration between the Debrecen and Catania ECR teams. In a first series, the X-ray spectroscopy was performed through silicon drift detectors and high purity germanium detectors, characterizing the volumetric plasma emission. The on-purpose developed collimation system was suitable for direct plasma density evaluation, performed "on-line" during beam extraction and charge state distribution characterization. A campaign for correlating the plasma density and temperature with the output charge states and the beam intensity for different pumping wave frequencies, different magnetic field profiles, and single-gas/gas-mixing configurations was carried out. The results reveal a surprisingly very good agreement between warm-electron density fluctuations, output beam currents, and the calculated electromagnetic modal density of the plasma chamber. A charge-coupled device camera coupled to a small pin-hole allowing X-ray imaging was installed and numerous X-ray photos were taken in order to study the peculiarities of the ECRIS plasma structure. PMID:26931918

  11. Status of a compact electron cyclotron resonance ion source for National Institute of Radiological Sciences-930 cyclotron

    SciTech Connect

    Hojo, S. Katagiri, K.; Nakao, M.; Sugiura, A.; Muramatsu, M.; Noda, A.; Noda, K.; Okada, T.; Takahashi, Y.; Komiyama, A.; Honma, T.

    2014-02-15

    The Kei-source is a compact electron cyclotron resonance ion source using only permanent magnets and a frequency of 10 GHz. It was developed at the National Institute of Radiological Sciences (NIRS) for producing C{sup 4+} ions oriented for high-energy carbon therapy. It has also been used as an ion source for the NIRS-930 cyclotron. Its microwave band region for the traveling-wave-tube amplifier and maximum output power are 8–10 GHz and 350 W, respectively. Since 2006, it has provided various ion beams such as proton, deuteron, carbon, oxygen, and neon with sufficient intensity (200 μA for proton and deuteron, 50 μA for C{sup 4+}, for example) and good stability for radioisotope production, tests of radiation damage, and basic research experiments. Its horizontal and vertical emittances were measured using a screen monitor and waist-scan. The present paper reports the current status of the Kei-source.

  12. Medical Transcriptionists: Making Medical Histories.

    ERIC Educational Resources Information Center

    Shniper, Lynn

    2001-01-01

    Medical transcriptionists are experts in the language of medicine. Describes what they do and what their working conditions, earnings, employment prospects, and training requirements are. Includes sources of additional information. (Author)

  13. New Measurement of the Electron Magnetic Moment and the Fine Structure Constant: A First Application of a One-Electron Quantum Cyclotron

    ScienceCinema

    Gabrielse, Gerald [Harvard University, Cambridge, Massachusetts, United States

    2009-09-01

    Remarkably, the famous UW measurement of the electron magnetic moment has stood since 1987. With QED theory, this measurement has determined the accepted value of the fine structure constant. This colloquium is about a new Harvard measurement of these fundamental constants. The new measurement has an uncertainty that is about six times smaller, and it shifts the values by 1.7 standard deviations. One electron suspended in a Penning trap is used for the new measurement, like in the old measurement. What is different is that the lowest quantum levels of the spin and cyclotron motion are resolved, and the cyclotron as well as spin frequencies are determined using quantum jump spectroscopy. In addition, a 0.1 mK Penning trap that is also a cylindrical microwave cavity is used to control the radiation field, to suppress spontaneous emission by more than a factor of 100, to control cavity shifts, and to eliminate the blackbody photons that otherwise stimulate excitations from the cyclotron ground state. Finally, great signal-to-noise for one-quantum transitions is obtained using electronic feedback to realize the first one-particle self-excited oscillator. The new methods may also allow a million times improved measurement of the 500 times small antiproton magnetic moment.

  14. Search for Cyclotron-maser Radio Emission from Extrasolar Planets

    NASA Astrophysics Data System (ADS)

    Dulk, G. A.; Leblanc, Y.; Bastian, T. S.

    1997-07-01

    There is reason to believe that extrasolar planets and/or brown dwarfs of mass about 1 to 50 M_J have magnetic fields, that they emit extremely intense cyclotron-maser radiation at metric wavelengths, and that this radiation may be detectable with sensitive radio telescopes like the VLA. The radiation is emitted at the electron cyclotron frequency, and has been detected from Earth, Jupiter, Saturn, Uranus and Neptune, from the Sun, from flare stars, and close binaries. The frequency range of cyclotron maser radiation is fixed by the magnetic field strength on the object. To be detected at, say 0.33 GHz, the required field strength is 118 G, which is intermediate between the 14 G field of Jupiter and the ~ 1000 G field of stellar active regions. An estimation of the flux density of the expected radiation can be made from an interpolation between Jupiter's radio emission (10(10) mJy at 5 AU) and that of nearby red dwarf stars ( ~ 100 mJy at 3 pc). Thus the flux from a planet or brown dwarf 3 to 30 times massive than Jupiter is plausibly 1 to 10 mJy, easily detectable with the VLA. If emission is detected, several important parameters about the planet can be deduced: the strength of its magnetic field, the period of its rotation, and the possible existence of a moon such as Jupiter's Io. Possible means of distinguishing stellar maser emissions from those of planets include: 1) Temporal variations and spectra differ from stars to planets. 2) The polarization is likely to be 100% circular or elliptical for planets, but not for stars. We have searched for exoplanet radio emission with 60 hours of observations with the VLA during November 1996. The observed stars with giant planets or brown dwarfs included 51 Peg, 70 Vir, 47 UMa, 55 CnC, Tau Boo, Gl 229, and HD 114762. We will present the method of observation, the limitations due to confusion and background noise, and the results.

  15. Oblique electron cyclotron emission for electron distribution studies (invited)

    NASA Astrophysics Data System (ADS)

    Preische, S.; Efthimion, P. C.; Kaye, S. M.

    1997-01-01

    Electron cyclotron emission (ECE) at an oblique angle to the magnetic field provides a means of probing the electron distribution function both in energy and physical space through changes in and constraints on the relativistic electron cyclotron resonance condition. Diagnostics based on this Doppler shifted resonance are able to study a variety of electron distributions through changes in the location of the resonance in physical or energy space accomplished by changes in the viewing angle and frequency, and the magnetic field. For the case of observation across a changing magnetic field, such as across the tokamak midplane, the constraint on the resonance condition for real solutions to the dispersion relation can constrain the physical location of optically thin emission. A new Oblique ECE diagnostic was installed and operated on the PBX-M tokamak for the study of energetic electrons during lower hybrid current drive. It has a view 33° with respect to perpendicular in the tokamak midplane, receives second harmonic X-mode emission, and is constrained to receive single pass emission by SiC viewing dumps on the tokamak walls. Spatial localization of optically thin emission from superthermal electrons (50-100 keV) was obtained by observation of emission upshifted from a thermal cyclotron harmonic. The localized measurements of the electron energy distribution and the superthermal density profile made by this diagnostic demonstrate its potential to study the spatial transport of energetic electrons on fast magnetohydrodynamic time scales or anomalous diffusion time scales. Oblique ECE can also be used to study electron distributions that may have a slight deviation from a Maxwellian by localizing the emission in energy space. In "near-Maxwellian" plasmas, the Doppler broadening of the resonance means that observed oblique ECE from optically thick harmonics will originate from electrons with energies near or slightly above the thermal energy [(1-2)vth for example, depending on the observation angle and spatial gradients]. This is different from observed perpendicular ECE from optically thick harmonics that originate from electrons below the thermal energy. Experiments are presently being performed on the Tore Supra tokamak with two oblique views of ECE in equal and opposite toroidal directions (approximately 25° with respect to perpendicular) using two Michelson interferometers capable of observing second and third harmonic emission in X mode.

  16. Electron cyclotron emission imaging and applications in magnetic fusion energy

    NASA Astrophysics Data System (ADS)

    Tobias, Benjamin John

    Energy production through the burning of fossil fuels is an unsustainable practice. Exponentially increasing energy consumption and dwindling natural resources ensure that coal and gas fueled power plants will someday be a thing of the past. However, even before fuel reserves are depleted, our planet may well succumb to disastrous side effects, namely the build up of carbon emissions in the environment triggering world-wide climate change and the countless industrial spills of pollutants that continue to this day. Many alternatives are currently being developed, but none has so much promise as fusion nuclear energy, the energy of the sun. The confinement of hot plasma at temperatures in excess of 100 million Kelvin by a carefully arranged magnetic field for the realization of a self-sustaining fusion power plant requires new technologies and improved understanding of fundamental physical phenomena. Imaging of electron cyclotron radiation lends insight into the spatial and temporal behavior of electron temperature fluctuations and instabilities, providing a powerful diagnostic for investigations into basic plasma physics and nuclear fusion reactor operation. This dissertation presents the design and implementation of a new generation of Electron Cyclotron Emission Imaging (ECEI) diagnostics on toroidal magnetic fusion confinement devices, or tokamaks, around the world. The underlying physics of cyclotron radiation in fusion plasmas is reviewed, and a thorough discussion of millimeter wave imaging techniques and heterodyne radiometry in ECEI follows. The imaging of turbulence and fluid flows has evolved over half a millennium since Leonardo da Vinci's first sketches of cascading water, and applications for ECEI in fusion research are broad ranging. Two areas of physical investigation are discussed in this dissertation: the identification of poloidal shearing in Alfven eigenmode structures predicted by hybrid gyrofluid-magnetohydrodynamic (gyrofluid-MHD) modeling, and magnetic field line displacement during precursor oscillations associated with the sawtooth crash, a disruptive instability observed both in tokamak plasmas with high core current and in the magnetized plasmas of solar flares and other interstellar plasmas. Understanding both of these phenomena is essential for the future of magnetic fusion energy, and important new observations described herein underscore the advantages of imaging techniques in experimental physics.

  17. Medical Renaissance.

    PubMed

    Toledo-Pereyra, Luis H

    2015-06-01

    The Medical Renaissance started as the regular Renaissance did in the early 1400s and ended in the late 1600s. During this time great medical personalities and scholar humanists made unique advances to medicine and surgery. Linacre, Erasmus, Leonicello and Sylvius will be considered first, because they fit the early classic Renaissance period. Andreas Vesalius and Ambroise Paré followed thereafter, making outstanding anatomical contributions with the publication of the "Human Factory" (1543) by Vesalius, and describing unique surgical developments with the publication of the "The Apologie and Treatise of Ambroise Paré." At the end of the Renaissance and beginning of the New Science, William Harvey, noted British medical doctor and cardiovascular researcher, discovered the general circulation. He published his findings in "The Motu Cordis" in 1628 (Figure 1). The Medical Renaissance, in summary, included a great number of accomplished physicians and surgeons who made especial contributions to human anatomy; Vesalius assembled detailed anatomical information; Paré advanced surgical techniques; and Harvey, a medical genius, detailed the circulatory anatomy and physiology. PMID:26065591

  18. Technical Note: Building a combined cyclotron and MRI facility: Implications for interference

    SciTech Connect

    Hofman, Mark B. M.; Kuijer, Joost P. A.; Ridder, Jan Willem de; Perk, Lars R.; Verdaasdonk, Rudolf M.

    2013-01-15

    Purpose: With the introduction of hybrid PET/MRI systems, it has become more likely that the cyclotron and MRI systems will be located close to each other. This study considered the interference between a cyclotron and a superconducting MRI system. Methods: Interactions between cyclotrons and MRIs are theoretically considered. The main interference is expected to be the perturbation of the magnetic field in the MRI due to switching on or off the magnetic field of the cyclotron. MR imaging is distorted by a dynamic spatial gradient of an external inplane magnetic field larger than 0.5-0.04 {mu}T/m, depending on the specific MR application. From the design of a cyclotron, it is expected that the magnetic fringe field at large distances behaves as a magnetic dipolar field. This allows estimation of the full dipolar field and its spatial gradients from a single measurement. Around an 18 MeV cyclotron (Cyclone, IBA), magnetic field measurements were performed on 5 locations and compared with calculations based upon a dipolar field model. Results: At the measurement locations the estimated and measured values of the magnetic field component and its spatial gradients of the inplane component were compared, and found to agree within a factor 1.1 for the magnetic field and within a factor of 1.5 for the spatial gradients of the field. In the specific case of the 18 MeV cyclotron with a vertical magnetic field and a 3T superconducting whole body MR system, a minimum distance of 20 m has to be considered to prevent interference. Conclusions: This study showed that a dipole model is sufficiently accurate to predict the interference of a cyclotron on a MRI scanner, for site planning purposes. The cyclotron and a whole body MRI system considered in this study need to be placed more than 20 m apart, or magnetic shielding should be utilized.

  19. Medical Biofilms

    PubMed Central

    2009-01-01

    For more than two decades, Biotechnology and Bioengineering has documented research focused on natural and engineered microbial biofilms within aquatic and subterranean ecosystems, wastewater and waste-gas treatment systems, marine vessels and structures, and industrial bioprocesses. Compared to suspended culture systems, intentionally engineered biofilms are heterogeneous reaction systems that can increase reactor productivity, system stability, and provide inherent cell: product separation. Unwanted biofilms can create enormous increases in fluid frictional resistances, unacceptable reductions in heat transfer efficiency, product contamination, enhanced material deterioration, and accelerated corrosion. Missing from B&B has been an equivalent research dialogue regarding the basic molecular microbiology, immunology, and biotechnological aspects of medical biofilms. Presented here are the current problems related to medical biofilms; current concepts of biofilm formation, persistence, and interactions with the host immune system; and emerging technologies for controlling medical biofilms. PMID:18366134

  20. Electromagnetic ion/ion cyclotron instability - Theory and simulations

    NASA Technical Reports Server (NTRS)

    Winske, D.; Omidi, N.

    1992-01-01

    Linear theory and 1D and 2D hybrid simulations are employed to study electromagnetic ion/ion cyclotron (EMIIC) instability driven by the relative streaming of two field-aligned ion beams. The characteristics of the instability are studied as a function of beam density, propagation angle, electron-ion temperature ratios, and ion beta. When the propagation angle is near 90 deg the EMIIC instability has the characteristics of an electrostatic instability, while at smaller angles electromagnetic effects play a significant role as does strong beam coupling. The 2D simulations point to a narrowing of the wave spectrum and accompanying coherent effects during the linear growth stage of development. The EMIIC instability is an important effect where ion beta is low such as in the plasma-sheet boundary layer and upstream of slow shocks in the magnetotail.

  1. Superconducting magnet for K-500 cyclotron at VECC, Kolkata

    NASA Astrophysics Data System (ADS)

    Saha, Subimal; Choudhury, Jayanta; Pal, Gautam; Hajra, D. P.; Dey, R.; Sur, Amitava; Bhandari, R. K.

    2009-06-01

    K-500 superconducting cyclotron is in the advanced stage of commissioning at VECC, Kolkata. Superconducting magnet is one of the major and critical component of the cyclotron. It has been successfully fabricated, installed, cooled down to 4.2 K by interfacing with LHe plant and energized to its rated current on 30th April, 2005 producing magnetic field of 4.8 T at median plane of cyclotron. The superconducting magnet (stored energy of 22MJ) consists of two coils (α and β), which were wound on a sophisticated coil winding machine set-up at VECC. The superconducting cable used for winding the coils is multi filamentary composite superconducting wire (1.29 mm diameter) having 500 filaments of 40 μm diameter Nb-Ti in copper matrix which is embedded in OFHC grade copper channel (2.794 mm × 4.978 mm) for cryogenic stability. The basic structure of coil consists of layer type helical winding on a SS bobbin of 1475 mm ID × 1930 mm OD × 1170 mm height. The bobbin was afterwards closed by SS sheet to form the LHe chamber. The total weight of the coil with bobbin was about 6 tonne and the total length of the superconducting cable wound was about 35 km. Winding was done at very high tension (2000 PSI) and close tolerance to restrict the movement of conductor and coil during energization. After coil winding, all four coils (two each on upper and lower half of median plane of cyclotron) were banded by aluminium strip (2.7 mm × 5 mm) at higher tension (20,000 PSI) to give more compressive force after cool down to 4.2 K for restricting the movement of coil while energizing and thereby eliminating the chances of quench during ramping of current. After completion of coil winding by October, 2003, cryostat assembly was taken up in house. The assembly of cryostat (13 tonne) with support links (9 Nos.) refrigeration port, instrumentation port, helium vapour cooled current loads, etc. was completed by June, 2004. Meanwhile assembly of magnet frame was taken up and the cryostat was positioned in the magnet frame with proper alignment by August, 2004. After installation of cryostat on magnet, the cryostat was connected to the helium refrigerator/liquefier, having refrigeration capacity of 200 W and 100 l/h in liquefier mode with LN2 pre-cooling. The cryogenic delivery system supplying the liquid helium and liquid nitrogen to the superconducting magnet was successfully commissioned in November, 2004. The cool down of the cryostat to 10 K took around 8 days following which the LHe was filled in the cryostat (300 l) on 15th January, 2005. Subsequently the superconducting coils (α and β) were energized by two DC current regulated power supplies (20 V, 1000 A, 10 ppm stability) with slow and fast dump resistors connected externally across the superconducting coils for protection of coils at the time of power failure and quench. The paper describes the intricacies involved in coil winding, winding set-up, assembly of cryostat, cooling down the superconducting coils, filling by LHe and energization to rated current. The paper also highlights the operating experience of superconducting magnet and related test results.

  2. 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.

  3. Grating monochromator for electron cyclotron resonance ion source operation

    SciTech Connect

    Muto, Hideshi; Ohshiro, Yukimitsu; Yamaka, Shouichi; Watanabe, Shin-ichi; Yamaguchi, Hidetoshi; Shimoura, Susumu; Oyaizu, Michihiro; Kase, Masayuki; Kubono, Shigeru; RIKEN Nishina Center for Accelerator-Based Science, Wako Saitama 351-0198; Institute of Modern Physics, Chinese Academy of Sciences, Nanchang Road 509, Lanzhou 730000 ; Hattori, Toshiyuki

    2013-07-15

    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.

  4. Magnetic-field measurements for the Lewis Research Center cyclotron

    NASA Technical Reports Server (NTRS)

    Fessler, T. E.

    1973-01-01

    The magnetic field of the Lewis Center cyclotron was mapped by using a Hall-effect magnetic-field transducer. Main-field Fourier coefficients were determined on a polar mesh of 40 radii for each of seven levels of main-field coil current. Incremental fields for eight sets of trim coils and two sets of harmonic coils were also determined at four of these main-field levels. A stored-program, digital computer was used to perform the measurements. The process was entirely automatic; all data-taking and data-reduction activities were specified by the computer programs. A new method for temperature compensation of a Hall element was used. This method required no temperature control of the element. Measurements of the Hall voltage and Hall-element resistance were sufficient to correct for temperature effects.

  5. Generation of accelerated electrons during cyclotron heating of plasmas

    SciTech Connect

    Suvorov, E.V.; Tokman, M.D.

    1988-08-01

    A qualitative theory is derived for the interaction of electrons with intense and spatially localized microwave radiation under cyclotron-resonance conditions. An adiabatic invariant which characterizes the dynamic system consisting of an electron in a static magnetic field and an rf electric field is pointed out. This invariant exists if the microwave amplitude is sufficiently high. Conditions are found under which, for any arbitrarily slow transit of the field region by an electron, the adiabatic invariant changes abruptly as the result of a qualitative change in the structure of the phase plane characterizing this dynamic system. In the course of such transits, the energy of the electrons may increase significantly, while an interaction does not lead to a change in energy during transits in which the adiabatic invariant is conserved.

  6. Electromagnetic ion cyclotron waves observed in the plasma depletion layer

    NASA Technical Reports Server (NTRS)

    Anderson, B. J.; Fuselier, S. A.; Murr, D.

    1991-01-01

    Observations from AMPTE/CCE in the earth's magnetosheath on October 5, 1984 are presented to illustrate 0.1 - 4.0 Hz magnetic field pulsations in the subsolar plasma depletion layer (PDL) for northward sheath field during a magnetospheric compression. The PDL is unambiguously identified by comparing CCE data with data from IRM in the upstream solar wind. Pulsations in the PDL are dominated by transverse waves with F/F(H+) 1.0 or less and a slot in spectral power at F/F(H+) = 0.5. The upper branch is left hand polarized while the lower branch is linearly polarized. In the sheath the proton temperature anisotropy is about 0.6 but it is about 1.7 in the PDL during wave occurrence. The properties and correlation of waves with increased anisotropy indicate that they are electromagnetic ion cyclotron waves.

  7. Characteristics of microinstabilities in electron cyclotron and ohmic heated discharges

    NASA Astrophysics Data System (ADS)

    Pusztai, I.; Moradi, S.; Fülöp, T.; Timchenko, N.

    2011-08-01

    Characteristics of microinstabilities in electron cyclotron (EC) and ohmic heated (OH) discharges in the T10 tokamak have been analyzed by linear electrostatic gyrokinetic simulations with gyro [J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] aiming to find insights into the effect of auxiliary heating on the transport. Trapped electron modes are found to be unstable in both OH and the EC heated scenarios. In the OH case the main drive is from the density gradient and in the EC case from the electron temperature gradient. The growth rates and particle fluxes exhibit qualitatively different scaling with the electron-to-ion temperature ratios in the two cases. This is mainly due to the fact that the dominant drives and the collisionalities are different. The inward flow velocity of impurities and the impurity diffusion coefficient decreases when applying EC heating, which leads to lower impurity peaking, consistently with experimental observations.

  8. Characteristics of microinstabilities in electron cyclotron and ohmic heated discharges

    SciTech Connect

    Pusztai, I.; Moradi, S.; Fueloep, T.; Timchenko, N.

    2011-08-15

    Characteristics of microinstabilities in electron cyclotron (EC) and ohmic heated (OH) discharges in the T10 tokamak have been analyzed by linear electrostatic gyrokinetic simulations with gyro[J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] aiming to find insights into the effect of auxiliary heating on the transport. Trapped electron modes are found to be unstable in both OH and the EC heated scenarios. In the OH case the main drive is from the density gradient and in the EC case from the electron temperature gradient. The growth rates and particle fluxes exhibit qualitatively different scaling with the electron-to-ion temperature ratios in the two cases. This is mainly due to the fact that the dominant drives and the collisionalities are different. The inward flow velocity of impurities and the impurity diffusion coefficient decreases when applying EC heating, which leads to lower impurity peaking, consistently with experimental observations.

  9. Alternative optical concept for electron cyclotron emission imaging.

    PubMed

    Liu, J X; Milbourne, T; Bitter, M; Delgado-Aparicio, L; Dominguez, A; Efthimion, P C; Hill, K W; Kramer, G J; Kung, C; Kubota, S; Kasparek, W; Lu, J; Pablant, N A; Park, H; Tobias, B

    2014-11-01

    The implementation of advanced electron cyclotron emission imaging (ECEI) systems on tokamak experiments has revolutionized the diagnosis of magnetohydrodynamic (MHD) activities and improved our understanding of instabilities, which lead to disruptions. It is therefore desirable to have an ECEI system on the ITER tokamak. However, the large size of optical components in presently used ECEI systems have, up to now, precluded the implementation of an ECEI system on ITER. This paper describes a new optical ECEI concept that employs a single spherical mirror as the only optical component and exploits the astigmatism of such a mirror to produce an image with one-dimensional spatial resolution on the detector. Since this alternative approach would only require a thin slit as the viewing port to the plasma, it would make the implementation of an ECEI system on ITER feasible. The results obtained from proof-of-principle experiments with a 125 GHz microwave system are presented. PMID:25430215

  10. Alternative optical concept for electron cyclotron emission imaging

    SciTech Connect

    Liu, J. X.; Milbourne, T.; Bitter, M.; Delgado-Aparicio, L.; Dominguez, A.; Efthimion, P. C.; Hill, K. W.; Kramer, G. J.; Kung, C.; Pablant, N. A.; Tobias, B.; Kubota, S.; Kasparek, W.; Lu, J.; Park, H.

    2014-11-15

    The implementation of advanced electron cyclotron emission imaging (ECEI) systems on tokamak experiments has revolutionized the diagnosis of magnetohydrodynamic (MHD) activities and improved our understanding of instabilities, which lead to disruptions. It is therefore desirable to have an ECEI system on the ITER tokamak. However, the large size of optical components in presently used ECEI systems have, up to now, precluded the implementation of an ECEI system on ITER. This paper describes a new optical ECEI concept that employs a single spherical mirror as the only optical component and exploits the astigmatism of such a mirror to produce an image with one-dimensional spatial resolution on the detector. Since this alternative approach would only require a thin slit as the viewing port to the plasma, it would make the implementation of an ECEI system on ITER feasible. The results obtained from proof-of-principle experiments with a 125 GHz microwave system are presented.

  11. Parametric instabilities during electron cyclotron heating of tandem mirrors

    NASA Technical Reports Server (NTRS)

    Nicholson, D. R.

    1984-01-01

    Electron cyclotron resonance heating is one of the most commonly used methods of heating electrons in the plugs and in the thermal barriers of tandem mirrors. The intense coherent electromagnetic waves used for such heating are susceptible to parametric decay into other modes. Significant growth rates are found for the decay of either ordinary or extraordinary waves into two magnetized electron plasma waves. This and related effects may result in electron heating mechanisms rather different than those assumed in linear ray-tracing calculations. These results may help explain the unusual effects observed during heating of the Phaedrus tandem mirror device. In the general case, these instabilities may be strongly inhibited by density gradients.

  12. Low radio frequency biased electron cyclotron resonance plasma etching

    NASA Astrophysics Data System (ADS)

    Samukawa, Seiji; Toyosato, Tomohiko; Wani, Etsuo

    1991-03-01

    A radio frequency (rf) biased electron cyclotron resonance (ECR) plasma etching technology has been developed to realize an efficient ion acceleration in high density and uniform ECR plasma for accurate Al-Si-Cu alloy film etching. In this technology, the substrate is located at the ECR position (875 G position) and the etching is carried out with a 400 kHz rf bias power. This Al-Si-Cu etching technology achieves a high etching rate (more than 5000 A/min), excellent etching uniformity (within ±5%), highly anisotropic etching, and Cu residue-free etching in only Cl2 gas plasma. These etching characteristics are accomplished by the combination of the dense and uniform ECR plasma generation at the ECR position with the efficient accelerated ion flux at the ECR position by using 400 kHz rf bias.

  13. Two-dimensional electron cyclotron emission imaging diagnostic for TEXTOR

    SciTech Connect

    Wang, J.; Domier, C.W.; Xia, Z.G.; Liang, Y.; Luhmann, N.C. Jr.; Park, H.; Munsat, T.; Mazzucato, E.; Pol, M.J. van de; Classen, I.G.J.; Donne, A.J.H.

    2004-10-01

    A two-dimensional electron cyclotron emission imaging (ECEI) diagnostic has been developed in which broad bandwidth radiation is collected by a vertically aligned mixer array and separated by frequency band. Using a 16 element array, and an 8 band receiver attached to each array element, time-resolved 16x8 images of electron temperature profiles and fluctuations of the TEXTOR plasma are acquired with vertical and horizontal channel spacings of 11 and 8 mm, and spot sizes of 13 and 9 mm, respectively. The system is wideband tunable from 95 to 130 GHz, and the focus location may be shifted horizontally via translation of one of the optical imaging elements. System design and laboratory testing details of the ECE Imaging optics and multichannel wideband electronics are presented, together with TEXTOR plasma data.

  14. Determination of the Electron Cyclotron Current Drive Profile

    SciTech Connect

    Luce, T.C.; Petty, C.C.; Schuster, D.I.; Makowski, M.A.

    1999-11-01

    Evaluation of the profile of non-inductive current density driven by absorption of electron cyclotron waves (ECCD) using time evolution of the poloidal flux indicated a broader profile than predicted by theory. To determine the nature of this broadening, a 1-1/2 D transport calculation of current density evolution was used to generate the signals which the DIII-D motional Stark effect (MSE) diagnostic would measure in the event that the current density evolution followed the neoclassical Ohm's law with the theoretical ECCD profile. Comparison with the measured MSE data indicates the experimental data is consistent with the ECCD profile predicted by theory. The simulations yield a lower limit on the magnitude of the ECCD which is at or above the value found in Fokker-Planck calculations of the ECCD including quasilinear and parallel electric field effects.

  15. Finite banana width effect on magnetoacoustic cyclotron instability

    SciTech Connect

    Chen, Y.P.; Tsai, S.T.

    1995-08-01

    The finite banana width (FBW) effect on the coupling between magnetoacoustic waves and the near harmonic gyro-oscillations of the energetic ions/{alpha} particles in tokamaks are studied. The gyrokinetic equation with FBW effect is rederived for the energetic trapped ions. The dispersion relation and growth rate of the magnetoacoustic cyclotron instability (MACI) are obtained. It is found that the coherence interaction between the energetic ion trajectory and mode field has a significant effect when the Larmor radius of energetic ions is larger than the wavelength of MACI. Near the low field side the FBW effect destabilizes the mode, while away from it the FBW gives a stabilizing effect. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  16. Observation of the backward electrostatic ion cyclotron wave

    SciTech Connect

    Goree, J.; Ono, M.; Wong, K.L.

    1984-12-01

    The backward branch of the electrostatic ion cyclotron wave has been observed, we believe, for the first time. The wave, which was driven by a phased antenna structure inserted in a neon plasma, exists in the parameter ranges 2T/sub i//m/sub i/ << (..omega../k/sub parallel/)/sup 2/ << 2T/sub e//m/sub e/, n..cap omega../sub i/ < ..omega.. < (n+1)..cap omega../sub i/, T/sub e/ greater than or equal to T/sub i/, and ..omega../sub pi/ > ..cap omega../sub i/. Double-tip probe interferomety data agree with the theoretical dispersion relation.

  17. 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.

  18. On ion cyclotron current drive for sawtooth control

    NASA Astrophysics Data System (ADS)

    Eriksson, L.-G.; Johnson, T.; Mayoral, M.-L.; Coda, S.; Sauter, O.; Buttery, R. J.; McDonald, D.; Hellsten, T.; Mantsinen, M. J.; Mueck, A.; Noterdaeme, J.-M.; Santala, M.; Westerhof, E.; de Vries, P.; contributors, JET-EFDA

    2006-10-01

    Experiments using ion cyclotron current drive (ICCD) to control sawteeth are presented. In particular, discharges demonstrating shortening of fast ion induced long sawteeth reported in (Eriksson et al 2004 Phys. Rev. Lett. 92 235004) by ICCD have been analysed in detail. Numerical simulations of the ICCD driven currents are shown to be consistent with the experimental observations. They support the hypothesis that an increase in the magnetic shear, due to the driven current, at the surface where the safety factor is unity was the critical factor for the shortening of the sawteeth. In view of the potential utility of ICCD, the mechanisms for the current drive have been further investigated experimentally. This includes the influence of the averaged energy of the resonating ions carrying the current and the spectrum of the launched waves. The results of these experiments are discussed in the light of theoretical considerations.

  19. Medical marijuana.

    PubMed

    1999-04-30

    The Florida Supreme Court heard oral arguments in April regarding a glaucoma patient's request for a medical exception to the State prohibition on use of marijuana. [Name removed] was convicted on possession and cultivation charges, and a trial judge refused to allow a medical necessity defense. A State appeals court subsequently overturned [name removed]'s conviction. The case focuses on whether the legislature intended to prohibit such a defense when it declared in 1993 that the substance had no medicinal benefits. PMID:11366533

  20. Medical leasing.

    PubMed

    Holden, Elizabeth A

    2012-01-01

    Leases for medical space can have far-reaching (and sometimes unintentional) consequences for the future of the practice and the costs of the business. In order to prevent hardship and expense down the line, it is especially important to review the lease to make sure that it reflects the practice's goals, needs, and structure. This article provides a number of provisions that are especially crucial to review and negotiate when leasing medical space, including use restrictions, assignment and subleasing clauses, build-out terms, and legal compliance requirements. PMID:22594070

  1. Medical genetics

    SciTech Connect

    Jorde, L.B.; Carey, J.C.; White, R.L.

    1995-10-01

    This book on the subject of medical genetics is a textbook aimed at a very broad audience: principally, medical students, nursing students, graduate, and undergraduate students. The book is actually a primer of general genetics as applied to humans and provides a well-balanced introduction to the scientific and clinical basis of human genetics. The twelve chapters include: Introduction, Basic Cell Biology, Genetic Variation, Autosomal Dominant and Recessive Inheritance, Sex-linked and Mitochondrial Inheritance, Clinical Cytogenetics, Gene Mapping, Immunogenetics, Cancer Genetics, Multifactorial Inheritance and Common Disease, Genetic Screening, Genetic Diagnosis and Gene Therapy, and Clinical Genetics and Genetic Counseling.

  2. 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.

  3. Heavy ion development at the LBL (Lawrence Berkeley Laboratory) 88-inch cyclotron

    SciTech Connect

    Clark, D.J.; Lyneis, C.M.

    1989-05-01

    The 88-Inch Cyclotron produces a wide range of ions for basic and applied research. The 6.4 GHz ECR source has completely replaced the PIG source, giving higher charge states and higher cyclotron energies. The ECR source has produced ions of 34 elements, of which 28 have been accelerated in the cyclotron, using gases, and low and high temperature ovens. A higher frequency 14.5 GHz advanced ECR is now under construction. It will further increase the charge states and energies available. A conceptual design has been done for a superconducting ECR driven by a gyrotron at 28 GHz. 8 refs., 5 figs., 1 tab.

  4. Design Features Of K = 100 Cyclotron Magnet For ISOL RIB Production

    SciTech Connect

    Park, Jin Ah; Gad, Kh. M. M.; Chai, Jong-Seo

    2011-06-01

    K = 100 Separated Sector Cyclotron was designed in conceptual for the ISOL driver. It has 4 separated sector magnets. Two SF cyclotrons will be used as the injectors for separated sector cyclotron. RF frequency is 70 MHz, 4th harmonics. We have designed sector magnet without trim and harmonic coils. Minimum radius of the magnet is 55 cm and maximum radius is 1.8 m. Designed magnets were calculated and simulated by OPERA 3D (TOSCA) code. Ion beam dynamics calculations have been done using particle studio code to prove the focusing properties of the designed magnets.

  5. Flash ionisation signature in coherent cyclotron emission from Brown Dwarfs

    NASA Astrophysics Data System (ADS)

    Vorgul, I.; Helling, Ch.

    2016-01-01

    Brown dwarfs form mineral clouds in their atmospheres, where charged particles can produce large-scale discharges in form of lightning resulting in substantial sudden increase of local ionisation. Brown dwarfs are observed to emit cyclotron radio emission. We show that signatures of strong transient atmospheric ionisation events (flash ionisation) can be imprinted on a pre-existing radiation. Detection of such flash ionisation events will open investigations into the ionisation state and atmospheric dynamics. Such events can also result from explosion shock waves, material outbursts or (volcanic) eruptions. We present an analytical model that describes the modulation of a pre-existing electromagnetic radiation by a time-dependent (flash) conductivity that is characteristic for flash ionisation events like lightning. Our conductivity model reproduces the conductivity function derived from observations of Terrestrial Gamma Ray Flashes, and is applicable to astrophysical objects with strong temporal variations in the local ionization, as in planetary atmospheres and protoplanetary disks. We show that the field responds with a characteristic flash-shaped pulse to a conductivity flash of intermediate intensity. More powerful ionisation events result in smaller variations of the initial radiation, or in its damping. We show that the characteristic damping of the response field for high-power initial radiation carries information about the ionisation flash magnitude and duration. The duration of the pulse amplification or the damping is consistently shorter for larger conductivity variations and can be used to evaluate the intensity of the flash ionisation. Our work suggests that cyclotron emission could be probe signals for electrification processes inside BD atmosphere.

  6. Flash ionization signature in coherent cyclotron emission from brown dwarfs

    NASA Astrophysics Data System (ADS)

    Vorgul, I.; Helling, Ch.

    2016-05-01

    Brown dwarfs (BDs) form mineral clouds in their atmospheres, where charged particles can produce large-scale discharges in the form of lightning resulting in substantial sudden increase of local ionization. BDs are observed to emit cyclotron radio emission. We show that signatures of strong transient atmospheric ionization events (flash ionization) can be imprinted on a pre-existing radiation. Detection of such flash ionization events will open investigations into the ionization state and atmospheric dynamics. Such events can also result from explosion shock waves, material outbursts or (volcanic) eruptions. We present an analytical model that describes the modulation of a pre-existing electromagnetic radiation by a time-dependent (flash) conductivity that is characteristic for flash ionization events like lightning. Our conductivity model reproduces the conductivity function derived from observations of terrestrial gamma-ray flashes, and is applicable to astrophysical objects with strong temporal variations in the local ionization, as in planetary atmospheres and protoplanetary discs. We show that the field responds with a characteristic flash-shaped pulse to a conductivity flash of intermediate intensity. More powerful ionization events result in smaller variations of the initial radiation, or in its damping. We show that the characteristic damping of the response field for high-power initial radiation carries information about the ionization flash magnitude and duration. The duration of the pulse amplification or the damping is consistently shorter for larger conductivity variations and can be used to evaluate the intensity of the flash ionization. Our work suggests that cyclotron emission could be probe signals for electrification processes inside BD atmosphere.

  7. Medical exceptionalism.

    PubMed

    Bliss, Michael

    2012-01-01

    How should we assess the historical development of health care? Many historians are deeply reluctant to endorse ideas involving progress in human affairs, including the evolution of modern medicine. We tend to think either that our present situation is little better than in the past, or that most kinds of value judgments about history are subjective and inappropriate. A laudatory approach to medical history commonly adopted by "amateur" medical historians in the tradition of Sir William Osler has often been eschewed by "professionals" as faulty, feel-good history. But Osler was right in his belief that, on balance, the progress of medicine has been spectacular, that modern health care offers one of the finest examples of the possibility of "man's redemption of man." Written objectively, medical history is about progress and achievement, and can properly seen as inspiring. If we mordantly or relativistically dismiss the unprecedentedly high quality of modern health care, we lose the ability to understand why citizens value it so highly, and this distorts our understanding of current issues. We also lose our sense of the wonders of human and medical achievement. PMID:23179032

  8. Medical genetics

    SciTech Connect

    Nora, J.J.; Fraser, F.C.

    1989-01-01

    This book presents a discussion of medical genetics for the practitioner treating or counseling patients with genetic disease. It includes a discussion of the relationship of heredity and diseases, the chromosomal basis for heredity, gene frequencies, and genetics of development and maldevelopment. The authors also focus on teratology, somatic cell genetics, genetics and cancer, genetics of behavior.

  9. Medical marijuana.

    PubMed

    Marmor, J B

    1998-06-01

    Although many clinical studies suggest the medical utility of marijuana for some conditions, the scientific evidence is weak. Many patients in California are self-medicating with marijuana, and physicians need data to assess the risks and benefits. The only reasonable solution to this problem is to encourage research on the medical effects of marijuana. The current regulatory system should be modified to remove barriers to clinical research with marijuana. The NIH panel has identified several conditions for which there may be therapeutic benefit from marijuana use and that merit further research. Marijuana should be held to the same evaluation standards of safety and efficacy as other drugs (a major flaw in Proposition 215) but should not have to be proved better than current medications for its use to be adopted. The therapeutic window for marijuana and THC between desired effect and unpleasant side effects is narrow and is a major reason for discontinuing use. Although the inhaled route of administration has the benefit of allowing patients to self-titrate the dose, the smoking of crude plant material is problematic. The NIH panel recommended that a high priority be given to the development of a controlled inhaled form of THC. The presence of a naturally occurring cannabinoid-receptor system in the brain suggests that research on selective analogues of THC may be useful to enhance its therapeutic effects and minimize adverse effects. PMID:9656007

  10. Electron cyclotron resonance heating by magnetic filter field in a negative hydrogen ion source

    NASA Astrophysics Data System (ADS)

    Kim, June Young; Cho, Won-Hwi; Dang, Jeong-Jeung; Chung, Kyoung-Jae; Hwang, Y. S.

    2016-02-01

    The influence of magnetic filter field on plasma properties in the heating region has been investigated in a planar-type inductively coupled radio-frequency (RF) H- ion source. Besides filtering high energy electrons near the extraction region, the magnetic filter field is clearly observed to increase the electron temperature in the heating region at low pressure discharge. With increasing the operating pressure, enhancement of electron temperature in the heating region is reduced. The possibility of electron cyclotron resonance (ECR) heating in the heating region due to stray magnetic field generated by a filter magnet located at the extraction region is examined. It is found that ECR heating by RF wave field in the discharge region, where the strength of an axial magnetic field is approximately ˜4.8 G, can effectively heat low energy electrons. Depletion of low energy electrons in the electron energy distribution function measured at the heating region supports the occurrence of ECR heating. The present study suggests that addition of axial magnetic field as small as several G by an external electromagnet or permanent magnets can greatly increase the generation of highly ro-vibrationally excited hydrogen molecules in the heating region, thus improving the performance of H- ion generation in volume-produced negative hydrogen ion sources.

  11. Distorted Cyclotron Line Profile in Cep X-4 as Observed by NuSTAR

    NASA Astrophysics Data System (ADS)

    Fürst, F.; Pottschmidt, K.; Miyasaka, H.; Bhalerao, V.; Bachetti, M.; Boggs, S. E.; Christensen, F. E.; Craig, W. W.; Grinberg, V.; Hailey, C. J.; Harrison, F. A.; Kennea, J. A.; Rahoui, F.; Stern, D.; Tendulkar, S. P.; Tomsick, J. A.; Walton, D. J.; Wilms, J.; Zhang, W. W.

    2015-06-01

    We present spectral analysis of Nuclear Spectroscopic Telescope Array and Swift observations of Cep X-4 during its outburst in 2014. We observed the source once during the peak of the outburst and once during the decay, finding good agreement in the spectral shape between the observations. We describe the continuum using a power law with a Fermi-Dirac cutoff at high energies. Cep X-4 has a very strong cyclotron resonant scattering feature (CRSF) around 30 keV. A simple absorption-like line with a Gaussian optical depth or a pseudo-Lorentzian profile both fail to describe the shape of the CRSF accurately, leaving significant deviations at the red side of the line. We characterize this asymmetry with a second absorption feature around 19 keV. The line energy of the CRSF, which is not influenced by the addition of this feature, shows a small but significant positive luminosity dependence. With luminosities between (1-6) × 1036 erg s-1, Cep X-4 is below the theoretical limit where such a correlation is expected. This behavior is similar to Vela X-1 and we discuss parallels between the two systems.

  12. Electron cyclotron resonance heating by magnetic filter field in a negative hydrogen ion source.

    PubMed

    Kim, June Young; Cho, Won-Hwi; Dang, Jeong-Jeung; Chung, Kyoung-Jae; Hwang, Y S

    2016-02-01

    The influence of magnetic filter field on plasma properties in the heating region has been investigated in a planar-type inductively coupled radio-frequency (RF) H(-) ion source. Besides filtering high energy electrons near the extraction region, the magnetic filter field is clearly observed to increase the electron temperature in the heating region at low pressure discharge. With increasing the operating pressure, enhancement of electron temperature in the heating region is reduced. The possibility of electron cyclotron resonance (ECR) heating in the heating region due to stray magnetic field generated by a filter magnet located at the extraction region is examined. It is found that ECR heating by RF wave field in the discharge region, where the strength of an axial magnetic field is approximately ∼4.8 G, can effectively heat low energy electrons. Depletion of low energy electrons in the electron energy distribution function measured at the heating region supports the occurrence of ECR heating. The present study suggests that addition of axial magnetic field as small as several G by an external electromagnet or permanent magnets can greatly increase the generation of highly ro-vibrationally excited hydrogen molecules in the heating region, thus improving the performance of H(-) ion generation in volume-produced negative hydrogen ion sources. PMID:26931999

  13. Electron-cyclotron wave propagation, absorption and current drive in the presence of neoclassical tearing modes

    NASA Astrophysics Data System (ADS)

    Isliker, Heinz; Chatziantonaki, Ioanna; Tsironis, Christos; Vlahos, Loukas

    2012-09-01

    We analyze the propagation of electron-cyclotron waves, their absorption and current drive when neoclassical tearing modes (NTMs), in the form of magnetic islands, are present in a tokamak plasma. So far, the analysis of the wave propagation and power deposition in the presence of NTMs has been performed mainly in the frame of an axisymmetric magnetic field, ignoring any effects from the island topology. Our analysis starts from an axisymmetric magnetic equilibrium, which is perturbed such as to exhibit magnetic islands. In this geometry, we compute the wave evolution with a ray-tracing code, focusing on the effect of the island topology on the efficiency of the absorption and current drive. To increase the precision in the calculation of the power deposition, the standard analytical flux-surface labeling for the island region has been adjusted from the usual cylindrical to toroidal geometry. The propagation up to the O-point is found to be little affected by the island topology, whereas the power absorbed and the driven current are significantly enhanced, because the resonant particles are bound to the small volumes in between the flux surfaces of the island. The consequences of these effects on the NTM evolution are investigated in terms of the modified Rutherford equation.

  14. Fluctuations in electron cyclotron resonance plasma in a divergent magnetic field

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, Sudeep; Fredriksen, Åshild; Chandra, Sayan

    2016-02-01

    The dependence of fluctuations on electron-neutral collision frequency (νen) and the radial location is investigated in an electron cyclotron resonance plasma in a divergent magnetic field region for a set of magnetic fields. Results indicate that the fluctuations depend strongly on the collision frequency. At lower magnetic fields and νen, the fluctuation levels are small and are observed to peak around 3-5 cm from the central plasma region. Coherent wave modes are found to contribute up to about 30% of the total fluctuation power, and two to three harmonics are present in the power spectra. There are two principal modes present in the discharge: one appears to be a dissipative mode associated with a collisional drift wave instability initiated at a lower pressure (collision frequencies) (˜0.5 mTorr) and is stabilized at a higher pressure (≳3 mTorr). The other mode appears at intermediate pressure (≳1.75 mTorr) and possesses the signature of a flute instability. The fluctuation levels indicate that flute modes are predominant in the discharge at higher pressures ( >1.75 mTorr) and at higher values of the magnetic field (˜540 Gauss).

  15. Ion Trap with Narrow Aperture Detection Electrodes for Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Nagornov, Konstantin O.; Kozhinov, Anton N.; Tsybin, Oleg Y.; Tsybin, Yury O.

    2015-05-01

    The current paradigm in ion trap (cell) design for Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) is the ion detection with wide aperture detection electrodes. Specifically, excitation and detection electrodes are typically 90° wide and positioned radially at a similar distance from the ICR cell axis. Here, we demonstrate that ion detection with narrow aperture detection electrodes (NADEL) positioned radially inward of the cell's axis is feasible and advantageous for FT-ICR MS. We describe design details and performance characteristics of a 10 T FT-ICR MS equipped with a NADEL ICR cell having a pair of narrow aperture (flat) detection electrodes and a pair of standard 90° excitation electrodes. Despite a smaller surface area of the detection electrodes, the sensitivity of the NADEL ICR cell is not reduced attributable to improved excite field distribution, reduced capacitance of the detection electrodes, and their closer positioning to the orbits of excited ions. The performance characteristics of the NADEL ICR cell are comparable with the state-of-the-art FT-ICR MS implementations for small molecule, peptide, protein, and petroleomics analyses. In addition, the NADEL ICR cell's design improves the flexibility of ICR cells and facilitates implementation of advanced capabilities (e.g., quadrupolar ion detection for improved mainstream applications). It also creates an intriguing opportunity for addressing the major bottleneck in FTMS—increasing its throughput via simultaneous acquisition of multiple transients or via generation of periodic non-sinusoidal transient signals.

  16. A PIXE mini-beam setup at the bonn cyclotron for archeometric metal analyses

    NASA Astrophysics Data System (ADS)

    Weber, J.; Beier, Th.; Diehl, U.; Lambrecht, D.; Mommsen, H.; Pantenburg, F. J.

    1990-04-01

    The exact analysis of the elemental composition at and around a soldering joint of an antique piece of jewelry can elucidate the joining technologies and give hints of the genuineness of the object. As analytical method we use PIXE, which is nondestructive, multielemental and with fundamental parameter calculations gives absolute concentration values. To obtain the necessary spot size of the H 2+ beam at the Bonn cyclotron we use a piezo-controlled diaphragm, whose demagnified image is focussed on the target by two magnetic quadrupole triplets. With an electrostatic deflector the beam spot of 0.1 0.3 mm 2 size can be moved 2 mm in each direction on the target. With a laser beam, which simulates the ion beam, an irregularly shaped archeological object can be positioned. The laser is also used to obtain the alignment of the target surface to the ion beam direction and the small beam size makes it easier to find a flat part on the surface of the object; both of these are important preconditions for using the fundamental parameter method. A scan over a joint of modern gold alloys demonstrates the ability to detect soldering joints. The analysis of four pieces of Roman gold jewelry found in the area of Cologne and Bonn shows examples of brazing with a solder as well as diffusion soldering.

  17. Ion beam formation in a gas-dynamic electron cyclotron resonance ion source

    NASA Astrophysics Data System (ADS)

    Sidorov, A.; Bokhanov, A.; Izotov, I.; Razin, S.; Skalyga, V.; Zorin, V.; Balabaev, A.; Kondrashev, S.; Geller, R.; Lamy, T.; Sortais, P.; Thuillier, T.; Spädtke, P.

    2006-03-01

    Generation of quasistationary flows of multicharged ions with a current density of up to 1A/cm2 from a dense electron cyclotron resonance plasma confined in a magnetic trap under the quasi-gas-dynamic regime has been achieved [Golubev et al., Trans. Fusion Sci. Technol. 47, 345 (2005)]. This technique provides opportunities for extracting high current multicharged ion beams. The present research is concerned with experimental and theoretical investigations of two ion extraction systems for the gas-dynamic ion sources. (1) Single-aperture system. In this case, there is a principal possibility to obtain ion beams with low emittance by using a small-diameter aperture for extraction. Here we describe investigations aimed at creating nitrogen ion beams (the main ion in the spectrum is N2+) with currents of up to 6.5mA through a 1.5mm aperture in the plasma electrode. (2) Multiaperture system. Such systems provide significantly higher beam currents. First results of testing an extractor with five apertures are presented in this article.

  18. Development of gas pulsing system for electron cyclotron resonance ion sourcea)

    NASA Astrophysics Data System (ADS)

    Hojo, S.; Honma, T.; Muramatsu, M.; Sakamoto, Y.; Sugiura, A.

    2008-02-01

    A gas-pulsing system for an electron cyclotron resonance ion source with all permanent magnets (Kei2 source) at NIRS has been developed and tested. The system consists of a small vessel (30ml) to reserve CH4 gas and two fast solenoid valves that are installed at both sides of the vessel. They are connected to each other and to the Kei2 source by using a stainless-steel pipe (4mm inner diameter), where the length of the pipe from the valve to the source is 60cm and the conductance is 1.2l /s. From the results of the test, almost 300eμA for a pulsed C4+12 beam was obtained at a Faraday cup in an extraction-beam channel with a pressure range of 4000Pa in the vessel. At this time, the valve has an open time of 10ms and the delay time between the valve open time and the application of microwave power is 100ms. In experiments, the conversion efficiency for input CH4 molecules to the quantity of extracted C4+12 ions in one beam pulse was found to be around 3% and the ratio of the total amount of the gas requirement was only 10% compared with the case of continuous gas provided in 3.3s of repetition in HIMAC.

  19. Development of gas pulsing system for electron cyclotron resonance ion source

    SciTech Connect

    Hojo, S.; Honma, T.; Muramatsu, M.; Sakamoto, Y.; Sugiura, A.

    2008-02-15

    A gas-pulsing system for an electron cyclotron resonance ion source with all permanent magnets (Kei2 source) at NIRS has been developed and tested. The system consists of a small vessel (30 ml) to reserve CH{sub 4} gas and two fast solenoid valves that are installed at both sides of the vessel. They are connected to each other and to the Kei2 source by using a stainless-steel pipe (4 mm inner diameter), where the length of the pipe from the valve to the source is 60 cm and the conductance is 1.2 l/s. From the results of the test, almost 300 e {mu}A for a pulsed {sup 12}C{sup 4+} beam was obtained at a Faraday cup in an extraction-beam channel with a pressure range of 4000 Pa in the vessel. At this time, the valve has an open time of 10 ms and the delay time between the valve open time and the application of microwave power is 100 ms. In experiments, the conversion efficiency for input CH{sub 4} molecules to the quantity of extracted {sup 12}C{sup 4+} ions in one beam pulse was found to be around 3% and the ratio of the total amount of the gas requirement was only 10% compared with the case of continuous gas provided in 3.3 s of repetition in HIMAC.

  20. Development of gas pulsing system for electron cyclotron resonance ion source.

    PubMed

    Hojo, S; Honma, T; Muramatsu, M; Sakamoto, Y; Sugiura, A

    2008-02-01

    A gas-pulsing system for an electron cyclotron resonance ion source with all permanent magnets (Kei2 source) at NIRS has been developed and tested. The system consists of a small vessel (30 ml) to reserve CH(4) gas and two fast solenoid valves that are installed at both sides of the vessel. They are connected to each other and to the Kei2 source by using a stainless-steel pipe (4 mm inner diameter), where the length of the pipe from the valve to the source is 60 cm and the conductance is 1.2 l/s. From the results of the test, almost 300 e microA for a pulsed (12)C(4+) beam was obtained at a Faraday cup in an extraction-beam channel with a pressure range of 4000 Pa in the vessel. At this time, the valve has an open time of 10 ms and the delay time between the valve open time and the application of microwave power is 100 ms. In experiments, the conversion efficiency for input CH(4) molecules to the quantity of extracted (12)C(4+) ions in one beam pulse was found to be around 3% and the ratio of the total amount of the gas requirement was only 10% compared with the case of continuous gas provided in 3.3 s of repetition in HIMAC. PMID:18315096