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1

Development of a Medical Cyclotron Production Facility  

NASA Astrophysics Data System (ADS)

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.

Allen, Danny R.

2003-08-01

2

Rotatable superconducting cyclotron adapted for medical use  

DOEpatents

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.

Blosser, Henry G. (East Lansing, MI); Johnson, David A. (Williamston, MI); Riedel, Jack (East Lansing, MI); Burleigh, Richard J. (Berkeley, CA)

1985-01-01

3

Initial Operation of CIAE medically used cyclotron  

NASA Astrophysics Data System (ADS)

CIAE medically used cyclotron is a 30 MeV fixed, isochronous field and fixed RF frequency machine with high -H beam intensity. -H beams with energy variable were obtained in December 1994 up to 0.4 mA. Two years operation has proved the design and manufacture successfully. The mapping results of magnetic field has shown the magnet perfect that would ensure the high intensity beam accelerated to the final energy. Now 7 medically useful isotopes were produced, e. g. thallium-201, cobalt-57, gallium-67, iodine-123 have been supplied for hospitals.

Fan, Mingwu; Zhang, Tainjue

1997-05-01

4

Ion source and injection line for high intensity medical cyclotron  

SciTech Connect

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 ?A/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 0.3??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 ?A 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.

Jia, XianLu, E-mail: jiaxl@ciae.ac.cn; Guan, Fengping; Yao, Hongjuan; Zhang, TianJue; Yang, Jianjun; Song, Guofang; Ge, Tao; Qin, Jiuchang [China Institute of Atomic Energy, Beijing (China)] [China Institute of Atomic Energy, Beijing (China)

2014-02-15

5

Ion source and injection line for high intensity medical cyclotron.  

PubMed

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 ?A/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 0.3??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 ?A 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. PMID:24593632

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

2014-02-01

6

Solid targets for 99mTc production on medical cyclotrons  

NASA Astrophysics Data System (ADS)

A method to produce solid 100Mo metal targets capable of withstanding proton irradiation with a power density of up to 1.1 kW/cm2 has been developed. The method of choice involves the electrodeposition of enriched 100Mo powder onto a tantalum backing, followed by high-temperature sintering in order to afford a coating that is sufficient to withstand bombardment for extended periods of time, yet reactive enough to allow for oxidative dissolution in seconds. This method is amenable to high-throughput techniques to allow for the production of 99mTc via the 100Mo(p,2n)99mTc reaction on small medical cyclotrons.

Hanemaayer, V.; Zeisler, S. K.; Buckley, K. R.; Klug, J.; Kovacs, M.; Bérnard, F.; Ruth, T. J.; Schaffer, P.

2012-12-01

7

Implementation of Multi-Curie Production of 99mTc by Conventional Medical Cyclotrons.  

PubMed

(99m)Tc is currently produced by an aging fleet of nuclear reactors, which require enriched uranium and generate nuclear waste. We report the development of a comprehensive solution to produce (99m)Tc in sufficient quantities to supply a large urban area using a single medical cyclotron. PMID:24722529

Bénard, François; Buckley, Kenneth R; Ruth, Thomas J; Zeisler, Stefan K; Klug, Julius; Hanemaayer, Victoire; Vuckovic, Milan; Hou, Xinchi; Celler, Anna; Appiah, Jean-Pierre; Valliant, John; Kovacs, Michael S; Schaffer, Paul

2014-04-10

8

Commercial and PET radioisotope manufacturing with a medical cyclotron  

NASA Astrophysics Data System (ADS)

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.

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

1993-06-01

9

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

SciTech Connect

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.

Hendriks, C.; Uittenbosch, T.; Cameron, D.; Kellogg, S.; Gray, D.; Buckley, K.; Schaffer, P.; Verzilov, V.; Hoehr, C. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada)] [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada)

2013-11-15

10

Integrated medical informatics with small group teaching in medical education  

Microsoft Academic Search

National Taiwan University College of Medicine (NTUCM) introduced small groups of teaching and basic-clinical integrated courses for medical students in 1992. By using computer network and multimedia techniques, this study tried to overcome barriers to learning in small group teaching. The Department of Medical Informatics of NTUCM established campus networking and computer classrooms and provided Internet and intranet network services

Heng-Shuen Chen; Fei-Ran Guo; Chien-Tsai Liu; Yue-Joe Lee; Jye-Horng Chen; Chia-Chin Lin; Sheng-Mou Hou; Bor-Shen Hsieh

1998-01-01

11

High-Current Superconducting Cyclotron for Accelerator-Driven Subcritical Fission and for Medical Isotope Production  

NASA Astrophysics Data System (ADS)

A 50 MeV, 5mA proton cyclotron is being developed as the injector for a high-current driver for an accelerator-driven subcritical fission power system (ADSMS), and also for production of isotopes for medical physics. Two innovations have made it possible to design a cyclotron capable of >5 mA beam current: strong-focusing of the bunches by quadrupole focusing channels integrated on the pole faces of the sector magnets, and superconducting rf accelerating cavities to provide sufficient energy gain per turn to cleanly separate the orbits. Simulation results will be presented for the beam dynamics of the intense proton bunches during injection, acceleration, and extraction. Key features for both applications will be discussed.

Badgley, Karie; Assadi, Saeed; McIntyre, Peter; Sattarov, Akhdiyor

2011-10-01

12

Measurement of thermal neutron fluence distribution with use of 23Na radioactivation around a medical compact cyclotron.  

PubMed

A medical compact cyclotron produces about 10(15) neutrons per day along with 100 GBq of (18)F. Therefore, it is important to establish radiation safety guidelines on residual radioactivity for routine operation, maintenance work, and decommissioning. Thus, we developed a simple method for measuring the thermal neutrons in a cyclotron room. In order to verify the feasibility of our proposed method, we measured the thermal neutron distribution around a cyclotron by using the activation of (23)Na in salt. We installed 78 salt dosimeters in the cyclotron room with a 50 cm mesh. The photopeak of (24)Na was measured, and the neutron flux distribution was estimated. Monitoring the neutron flux distribution in a cyclotron room appears to be useful for not only obtaining an accurate estimate of the distribution of induced radioactivity, but also optimizing the shield design for radiation safety in preparation for the decommissioning process. PMID:20821115

Fujibuchi, Toshioh; Yamaguchi, Ichiro; Kasahara, Tetsuharu; Iimori, Takashi; Masuda, Yoshitada; Kimura, Ken-ichi; Watanabe, Hiroshi; Isobe, Tomonori; Sakae, Takeji

2009-07-01

13

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

SciTech Connect

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.

Egle, Brian [ORNL] [ORNL; Mirzadeh, Saed [ORNL] [ORNL; Tatum, B Alan [ORNL] [ORNL; Varma, Venugopal Koikal [Oak Ridge National Laboratory (ORNL)] [Oak Ridge National Laboratory (ORNL); Bradley, Eric Craig [ORNL] [ORNL; Burgess, Thomas W [ORNL] [ORNL; Aaron, W Scott [ORNL] [ORNL; Binder, Jeffrey L [ORNL] [ORNL; Beene, James R [ORNL] [ORNL; Saltmarsh, Michael John [ORNL] [ORNL

2013-01-01

14

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

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

15

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

DOEpatents

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.

Ohkawa, Tihiro (La Jolla, CA)

1987-01-01

16

Effect of imperfections of the radial component of a magnetic field on beam dynamics in medical cyclotron C235-V3  

NASA Astrophysics Data System (ADS)

This paper presents numerical simulations and experimental results related to the effect of imperfections of the radial component of a magnetic field on the beam dynamics in the medical cyclotron C235-V3 of the Dimitrovgrad Proton Therapy Center. These imperfections in the region of the minimal axial betatron frequency lead to a transformation of coherent motion of the center of gravity of the beam to the incoherent motion of separate particles. The radial component increases the axial size of the beam by a factor of 2 at a radius of 20 cm, which produces additional losses of protons. To reduce undesirable actions of the radial component on the axial motion, the magnetic system in the central region has been optimized using two procedures: the positioning of shim correctors on sectors and selecting a special asymmetric arrangement of the upper and lower central plugs. This led to a twofold reduction in the axial size of the beam and a decrease in proton losses. Eventually, the beam transmission in C235-V3 has been increased to 72% without a limiting aperture diaphragm, which is commonly used in cyclotrons of this type. This makes it possible to reduce the irradiation dose of machine elements and increase the beam current at a deflector entrance of the cyclotron C235-V3 by a factor of 1.5 when compared to a serial C235 cyclotron.

Karamysheva, G. A.; Kostromin, S. A.; Morozov, N. A.; Samsonov, E. V.; Syresin, E. M.

2014-11-01

17

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

PubMed

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 310?Sv/y, which is smaller than the recommended dose limit for workers. PMID:23419430

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

2013-04-01

18

New considerations for compact cyclotrons  

E-print Network

A compact cyclotron built with superconducting magnets could be a transformative solution to many scientific problems facing the defense, medical, and energy industries today. This thesis discusses three potential applications ...

Marshall, Eric S. (Eric Scott)

2012-01-01

19

Simulating the impact of medical savings accounts on small business.  

PubMed Central

OBJECTIVE: To simulate whether allowing small businesses to offer employer-funded medical savings accounts (MSAs) would change the amount or type of insurance coverage. STUDY SETTING: Economic policy evaluation using a national probability sample of nonelderly non-institutionalized Americans from the 1993 Current Population Survey (CPS). STUDY DESIGN: We used a behavioral simulation model to predict the effect of MSAs on the insurance choices of employees of small businesses (and their families). The model predicts spending by each family in a FFS plan, an HMO plan, an MSA, and no insurance. These predictions allow us to compute community-rated premiums for each plan, but with firm-specific load fees. Within each firm, employees then evaluate each option, and the firm decides whether to offer insurance-and what type-based on these evaluations. If firms offer insurance, we consider two scenarios: (1) all workers elect coverage; and (2) workers can decline the coverage in return for a wage increase. PRINCIPAL FINDINGS: In the long run, under simulated conditions, tax-advantaged MSAs could attract 56 percent of all employees offered a plan by small businesses. However, the fraction of small-business employees offered insurance increases only from 41 percent to 43 percent when MSAs become an option. Many employees now signing up for a FFS plan would switch to MSAs if they were universally available. CONCLUSIONS: Our simulations suggest that MSAs will provide a limited impetus to businesses that do not currently cover insurance. However, MSAs could be desirable to workers in firms that already offer HMOs or standard FFS plans. As a result, expanding MSA availability could make it a major form of insurance for covered workers in small businesses. Overall welfare would increase slightly. PMID:10778824

Goldman, D P; Buchanan, J L; Keeler, E B

2000-01-01

20

Cyclotrons and positron emitting radiopharmaceuticals  

SciTech Connect

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)

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

1984-01-01

21

Small-size pulsed lasers in medical applications  

Microsoft Academic Search

The application of physics concepts to solve biological and medical problems are of growing interest. There are strong efforts to study the use of pulsed laser system in medical applications like dermatology, surgery, dental medicine and ophthalmology. Laser wavelengths cover a wide range from the ultraviolet to the far infrared. The most common radiation sources include all kind of lasers

M. Iberler; K. Frank

2002-01-01

22

Productive Small Groups in Medical Studies: Training for Cooperative Learning.  

ERIC Educational Resources Information Center

A self-help group approach was used to enhance medical students' cooperative skills within an elective course. The task profile envisaged included team building, cooperative information search and problem-solving skills, and providing and receiving constructive feedback. Findings suggest that training for productive cooperative learning is useful…

Sobral, Dejano T.

1998-01-01

23

Medical and Health Information Needs in a Small Community.  

ERIC Educational Resources Information Center

Reports on research by library science students for a public library to determine the information needs of a community's health-care professionals, their views of patient information needs, and the public library's ability to meet those needs. An added benefit was positive public relations with the medical community. (Contains 14 references.) (EAM)

Broadway, Marsha D.; Christensen, Steven B.

1993-01-01

24

Small amplitude low-field magnetoresistance oscillation in unidirectional lateral superlattices: Geometric resonance of Bragg-reflected cyclotron orbits  

E-print Network

Small amplitude low-field magnetoresistance oscillation in unidirectional lateral superlattices October 2004; published 9 February 2005 We have uncovered small amplitude magnetoresistance oscillations, as a small undulation on top of a well-known positive magnetoresistance background. The positions of maxima

Iye, Yasuhiro

25

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

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.

Friedman, P.G.

1986-11-25

26

Factors Influencing Electronic Clinical Information Exchange in Small Medical Group Practices  

ERIC Educational Resources Information Center

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…

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

2012-01-01

27

Radiation surveillance in and around cyclotron facility  

PubMed Central

The cyclotron is the most widely used particle accelerator for producing medically important radio nuclides. Many medical centers in India have installed compact medical cyclotrons for on-site production of short-lived positron-emitting radio nuclides such as 18F, 13N, and 11C. A mandatory requirement for cyclotron installation is radiation control permit from Atomic Energy Regulatory Board. Cyclotron radiation survey is an integral part of the overall radiation safety in the cyclotron facility. Radiation surveillance in and around a newly installed cyclotron was performed using ionization chamber counter and Geiger Muller counter before, during and after operating the cyclotron. The readings were recorded at various locations where a high radiation field was expected. The results were recorded, tabulated and analyzed. The highest exposure level (0.93 ?Sv) was found at the back wall of the radiochemistry lab facing the cyclotron vault. Reason for the high exposure of 0.93 ?Sv/h: Synthesis of 18F-Fluoro-Deoxy-Glucose (18F-FDG) was going in the synthesis module and activity (18F) was present in the synthesis module when reading was taken. All other values were found to be below the recommended levels of exposure. PMID:24019654

Kaur, Amandeep; Sharma, Sarika; Mittal, BR

2012-01-01

28

Evaluation of Small-Group Teaching in Human Gross Anatomy in a Caribbean Medical School  

ERIC Educational Resources Information Center

Although there are a number of medical schools in the Caribbean islands, very few reports have come out so far in the literature regarding the efficacy of small-group teaching in them. The introduction of small-group teaching in the gross anatomy laboratory one and a half years ago at St. Matthew's University (SMU) on Grand Cayman appears to have…

Chan, Lap Ki; Ganguly, Pallab K.

2008-01-01

29

Workflow and Electronic Health Records in Small Medical Practices  

PubMed Central

This paper analyzes the workflow and implementation of electronic health record (EHR) systems across different functions in small physician offices. We characterize the differences in the offices based on the levels of computerization in terms of workflow, sources of time delay, and barriers to using EHR systems to support the entire workflow. The study was based on a combination of questionnaires, interviews, in situ observations, and data collection efforts. This study was not intended to be a full-scale time-and-motion study with precise measurements but was intended to provide an overview of the potential sources of delays while performing office tasks. The study follows an interpretive model of case studies rather than a large-sample statistical survey of practices. To identify time-consuming tasks, workflow maps were created based on the aggregated data from the offices. The results from the study show that specialty physicians are more favorable toward adopting EHR systems than primary care physicians are. The barriers to adoption of EHR systems by primary care physicians can be attributed to the complex workflows that exist in primary care physician offices, leading to nonstandardized workflow structures and practices. Also, primary care physicians would benefit more from EHR systems if the systems could interact with external entities. PMID:22737096

Ramaiah, Mala; Subrahmanian, Eswaran; Sriram, Ram D; Lide, Bettijoyce B

2012-01-01

30

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

PubMed Central

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

Brandon, Alfred N.

1967-01-01

31

Selected List of Books and Journals for the Small Medical Library  

PubMed Central

This list of 358 books and 123 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:14308899

Brandon, Alfred N.

1965-01-01

32

Small and medium-size physician practices use few patient-centered medical home processes.  

PubMed

The patient-centered medical home has become a prominent model for reforming the way health care is delivered to patients. The model offers a robust system of primary care combined with practice innovations and new payment methods. But scant information exists about the extent to which typical US physician practices have implemented this model and its processes of care, or about the factors associated with implementation. In this article we provide the first national data on the use of medical home processes such as chronic disease registries, nurse care managers, and systems to incorporate patient feedback, among 1,344 small and medium-size physician practices. We found that on average, practices used just one-fifth of the patient-centered medical home processes measured as part of this study. We also identify internal capabilities and external incentives associated with the greater use of medical home processes. PMID:21719447

Rittenhouse, Diane R; Casalino, Lawrence P; Shortell, Stephen M; McClellan, Sean R; Gillies, Robin R; Alexander, Jeffrey A; Drum, Melinda L

2011-08-01

33

Development of a high current H- ion source for cyclotrons  

NASA Astrophysics Data System (ADS)

A multi-cusp DC H- ion source has been designed and fabricated for medical applications of cyclotrons. Optimization of the ion source is in progress, such as the improvement of the filament configuration, magnetic filter strength, extraction electrode's shape, configuration of electron suppression magnets, and plasma electrode material. A small quantity of Cs has been introduced into the ion source to enhance the negative ion beam current. The ion source produced 16 mA of DC H- ion beam with the Cs-seeded operation at a low arc discharge power of 2.8 kW.

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

2014-02-01

34

Development of a high current H(-) ion source for cyclotrons.  

PubMed

A multi-cusp DC H(-) ion source has been designed and fabricated for medical applications of cyclotrons. Optimization of the ion source is in progress, such as the improvement of the filament configuration, magnetic filter strength, extraction electrode's shape, configuration of electron suppression magnets, and plasma electrode material. A small quantity of Cs has been introduced into the ion source to enhance the negative ion beam current. The ion source produced 16 mA of DC H(-) ion beam with the Cs-seeded operation at a low arc discharge power of 2.8 kW. PMID:24593547

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

2014-02-01

35

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

SciTech Connect

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.

Dence, C.S.; Welch, M.J. [Washington Univ., St. Louis, MO (United States)

1994-12-31

36

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

PubMed Central

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

Brandon, Alfred N.

1971-01-01

37

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

PubMed Central

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

Brandon, Alfred N.

1969-01-01

38

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

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

39

H- superconducting cyclotron for PET isotope production  

NASA Astrophysics Data System (ADS)

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 ?A. 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.

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

2014-11-01

40

Small group effectiveness in a Caribbean medical school’s problem-based learning sessions  

PubMed Central

Purpose: The Tutorial Group Effectiveness Instrument was developed to provide objective information on the effectiveness of small groups. Student perception of small group effectiveness during the problem base learning (PBL) process has not been previously studied in Xavier University School of Medicine (Aruba, Kingdom of the Netherlands); hence, the present study was carried out. Methods: The study was conducted among second and third semester undergraduate medical students during the last week of September 2013, at Xavier University School of Medicine of the Netherlands. Students were informed about the objectives of the study and invited to participate after obtaining written, informed consent. Demographic information like gender, age, nationality, and whether the respondent had been exposed to PBL before joining the institution was noted. Student perception about small group effectiveness was studied by noting their degree of agreement with a set of 19 statements using a Likert-type scale. Results: Thirty-four of the 37 (91.9%) second and third semester medical students participated in the study. The mean cognitive score was 3.76 while the mean motivational and de-motivational scores were 3.65 and 2.51, respectively. The median cognitive category score was 27 (maximum score 35) while the motivation score was 26 (maximum score 35) and the de-motivational score was 12 (maximum score25). There was no significant difference in scores according to respondents’ demographic characteristics. Conclusion: Student perception about small group effectiveness was positive. Since most medical schools worldwide already have or are introducing PBL as a learning modality, the Tutorial Group Effectiveness Instrument can provide valuable information about small group functioning during PBL sessions. PMID:24699510

2014-01-01

41

Synchrotrons in cyclotron territory  

SciTech Connect

Synchrotrons and cyclotrons have an overlap in their particle and energy ranges. In proton radiotherapy, synchrotrons are proposed at 250 MeV, an energy usually served by cyclotrons. Heavy ion therapy has been synchrotron territory, but cyclotrons may be competitive. In nuclear science, heavy ion synchrotrons can be used in the cyclotron energy range of 10-200 MeV/u. Storage rings are planned to increase the flexibility of several cyclotrons. For atomic physics research, several storage rings are under construction for the energy range of 10 MeV/u and below.

Clark, D.J.; Gough, R.A.

1986-10-01

42

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

NASA Astrophysics Data System (ADS)

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.

Tachimori, Yutaka; Iwanaga, Hiroaki; Tahara, Takashi

2013-12-01

43

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

PubMed Central

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

Brandon, A N; Hill, D R

1979-01-01

44

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

PubMed Central

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

Brandon, A N; Hill, D R

1981-01-01

45

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

PubMed Central

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

Brandon, A N

1977-01-01

46

Dose estimation of the radiation workers in the SK cyclotron center using dual-TLD method  

Microsoft Academic Search

The Cyclotron Center in Shin Kong Wu Ho-Su Memorial Hospital (SK Cyclotron Center) produced the 18F-FDG compound and provided it to the Positron Emission Tomography (PET) center for diagnosis services. The works in SK Cyclotron Center are distinguished into three procedures including production, dispensation, and carry of the compound. As the medical cyclotron was operated to produce the radioactive compounds,

Ming-Jay Kuo; Fang-Yuh Hsu; Ching-Han Hsu; Ching-Huang Lo; Chien-Ming Chen; Yen-Lin Chang; Jiunn-Hsing Chao; Kuo-Wei Yin

2010-01-01

47

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

PubMed Central

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

Brandon, Alfred N.

1973-01-01

48

Evaluation of small-group teaching in human gross anatomy in a Caribbean medical school  

NSDL National Science Digital Library

Although there are a number of medical schools in the Caribbean islands, very few reports have come out so far in the literature regarding the efficacy of small-group teaching. The introduction of small-group teaching in the gross anatomy laboratory one and a half years ago at St. Matthew's University (SMU) on Grand Cayman appears to have had a significant positive impact on the academic achievement of students in anatomy. This study surveyed the responses of the students to the small-group learning method in gross anatomy at SMU using a structured questionnaire. The results show that our students prefer this small-group learning method over a completely self-directed method in the gross anatomy lab because the study materials were carefully chosen and the study objectives were demonstrated by the resource person. However, teacher-centered teaching was deliberately avoided by fostering problem-solving skills in the anatomy lab sessions. Another aim of the small-group teaching at SMU was to develop the interpersonal and communication skills of the students, which are important in their later education and career.

Dr. Lap Ki Chan (The University of Hong Kong)

2008-01-01

49

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

PubMed Central

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

Brandon, A N; Hill, D R

1985-01-01

50

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

PubMed Central

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

Brandon, A N

1975-01-01

51

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

PubMed Central

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

Brandon, A N; Hill, D R

1983-01-01

52

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

PubMed Central

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

Brandon, A N; Hill, D R

1987-01-01

53

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

PubMed Central

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

Brandon, A N; Hill, D R

1989-01-01

54

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

PubMed Central

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

Brandon, A N; Hill, D R

1991-01-01

55

Basic steps in establishing effective small group teaching sessions in medical schools.  

PubMed

Small-group teaching and learning has achieved an admirable position in medical education and has become more popular as a means of encouraging the students in their studies and enhance the process of deep learning. The main characteristics of small group teaching are active involvement of the learners in entire learning cycle and well defined task orientation with achievable specific aims and objectives in a given time period. The essential components in the development of an ideal small group teaching and learning sessions are preliminary considerations at departmental and institutional level including educational strategies, group composition, physical environment, existing resources, diagnosis of the needs, formulation of the objectives and suitable teaching outline. Small group teaching increases the student interest, teamwork ability, retention of knowledge and skills, enhance transfer of concepts to innovative issues, and improve the self-directed learning. It develops self-motivation, investigating the issues, allows the student to test their thinking and higher-order activities. It also facilitates an adult style of learning, acceptance of personal responsibility for own progress. Moreover, it enhances student-faculty and peer-peer interaction, improves communication skills and provides opportunity to share the responsibility and clarify the points of bafflement. PMID:24353692

Meo, Sultan Ayoub

2013-07-01

56

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

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,…

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

57

Development of a small wireless position sensor for medical capsule devices.  

PubMed

Medical capsule devices such as video capsule endoscopes are finding increasing use in clinical applications. At present, technologies capable of measuring capsule position in the digestive tract have not yet been established. The present study aims to develop a small wireless position sensor capable of measuring capsule position based on the phenomenon of mutual induction. Currents into primary coils are adjusted to maintain electromotive force induced in secondary coils at a constant level. Electromotive forces induced in the secondary coils are modulated to FM signals using an astable multivibrator, and the signals are passed directly through living tissue at low current and then demodulated by detectors on the surface of the body. A prototype wireless sensor was developed and evaluated in vitro. The sensor was capable of accurately measuring capsule position up to 500 (mm) from the primary coils with an accuracy of 5 (mm). Miniaturization of the sensor is necessary for commercialization. PMID:17272146

Nagaoka, T; Uchiyama, A

2004-01-01

58

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

PubMed Central

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

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

59

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

SciTech Connect

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.

Chu, William T.

2005-09-01

60

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

PubMed Central

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

Brandon, A N; Hill, D R

1995-01-01

61

Design of small-animal thermal neutron irradiation facility at the Brookhaven Medical Research Reactor  

SciTech Connect

The broad beam facility (BBF) at the Brookhaven Medical Research Reactor (BMRR) can provide a thermal neutron beam with flux intensity and quality comparable to the beam currently used for research on neutron capture therapy using cell-culture and small-animal irradiations. Monte Carlo computations were made, first, to compare with the dosimetric measurements at the existing BBF and, second, to calculate the neutron and gamma fluxes and doses expected at the proposed BBF. Multiple cell cultures or small animals could be irradiated simultaneously at the so-modified BBF under conditions similar to or better than those individual animals irradiated at the existing thermal neutron irradiation Facility (TNIF) of the BMRR. The flux intensity of the collimated thermal neutron beam at the proposed BBF would be 1.7 {times} 10{sup 10} n/cm{sup 2}{center_dot}s at 3-MW reactor power, the same as at the TNIF. However, the proposed collimated beam would have much lower gamma (0.89 {times} 10{sup {minus}11} cGy{center_dot}cm{sup 2}/n{sub th}) and fast neutron (0.58 {times} 10{sup {minus}11} cGy{center_dot}cm{sup 2}/n{sub th}) contaminations, 64 and 19% of those at the TNIF, respectively. The feasibility of remodeling the facility is discussed.

Liu, H.B. [Brookhaven National Lab., Upton, NY (United States). Medical Dept.

1996-09-01

62

Cyclotron Institute Upgrade Project  

SciTech Connect

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.

Clark, Henry [Texas A& M University; Yennello, Sherry [Texas A& M University; Tribble, Robert [Texas A& M University

2014-08-26

63

ECR Ion Source for a High-Brightness Cyclotron  

NASA Astrophysics Data System (ADS)

New technology is being developed for high-brightness, high-current cyclotrons with performance benefits for accelerator-driven subcritical fission power, medical isotope production, and proton beam cancer therapy. This paper describes the design for a 65 kV electron cyclotron resonance (ECR) ion source that will provide high-brightness beam for injection into the cyclotron. The ion source is modeled closely upon the one that is used at the Paul Scherrer Institute. Modifications are being made to provide enhanced brightness and compatibility for higher-current operation.

Comeaux, Justin; McIntyre, Peter; Assadi, Saeed

2011-10-01

64

Design study of a superconducting cyclotron for heavy ion therapy  

Microsoft Academic Search

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

J. Kim; F. Marti; H. Blosser

2001-01-01

65

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

PubMed Central

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

Chiang, Michael F.; Starren, Justin B.

2002-01-01

66

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

SciTech Connect

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.

Rogers, David E.C. [Environmental Process Solutions, Process Technology Centre, Council for Scientific and Industrial Research (CSIR), P.O. Box 395, Pretoria 0001 (South Africa)]. E-mail: drogers@csir.co.za; Brent, Alan C. [Life Cycle Engineering, Department of Engineering and Technology Management, University of Pretoria, Room 4-12, Engineering 2, Pretoria 0002 (South Africa)

2006-07-01

67

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

PubMed Central

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

Hill, Dorothy R.; Stickell, Henry N.

2001-01-01

68

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

PubMed Central

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

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

69

Medical Engineering Education for Engineers Working in Small & Medium Sized Enterprise  

NASA Astrophysics Data System (ADS)

Medical device industry is expected to be one of the growing fields in coming years, because a large amount of medical bill expenditure becomes pressing matters to overcome in Japan?s rapidly aging society. Authors have developed medical engineering programs for SMe?s to meet these demand by the government grant under academia-industry collaboration in this region and were successful to put these programs into practice. We have two medical engineering education programs in Kobe-Kansai region, one is by graduate school of Kobe University, and the other is non degree program by Kobe City Industrial Promotion Foundation. Present situation of these education are described.

Nagai, Chiaki; Moriwaki, Toshimichi

70

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

PubMed

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

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

1997-01-01

71

The Story of a Small Campaign: The Medical Arrangements during the Burma Rebellion, 1931  

PubMed Central

(1) A general description of Burma, its climate and seasons.—(2) The medical experience of former campaigns in Burma.—(3) Medical resources available and methods adopted to preserve the health of the troops, with special reference to accommodation, water supplies, malaria, heat-stroke and veneral disease. PMID:19989209

West, J. W.

1933-01-01

72

Decay of References to Web sites in Articles Published in General Medical Journals: Mainstream vs Small Journals  

PubMed Central

Summary Background Over the last decade, Web sites (URLs) have been increasingly cited in scientific articles. However, the contents of the page of interest may change over the time. Objective To investigate the trend of citation to URLs in five general medical journals since January 2006 to June 2013 and to compare the trends in mainstream journals with small journals. Methods References of all original articles and review articles published between January 2006 and June 2013 in three regional journals – Archives of Iranian Medicine (AIM), Eastern Mediterranean Health Journal (EMHJ), and Journal of Postgraduate Medical Institute (JPMI) – and two mainstream journals – The Lancet and British Medical Journal (BMJ) – were reviewed. The references were checked to determine the frequency of citation to URLs as well as the rate of accessibility of the URLs cited. Results A total of 2822 articles was studied. Since January 2006 onward, the number of citations to URLs increased in the journals (doubling time ranged from 4.2 years in EMHJ to 13.9 years in AIM). Overall, the percentage of articles citing at least one URL has increased from 24% in 2006 to 48.5% in 2013. Accessibility to URLs decayed as the references got old (half life ranged from 2.2 years in EMHJ to 5.3 years in BMJ). The ratio of citation to URLs in the studied mainstream journals, as well as the ratio of URLs accessible were significantly (p<0.001) higher than the small medical journals. Conclusion URLs are increasingly cited, but their contents decay with time. The trend of citing and decaying URLs are different in mainstream journals compared to small medical journals. Decay of URL contents would jeopardize the accuracy of the references and thus, the body of evidence. One way to tackle this important obstacle is to archive URLs permanently. PMID:24454575

Habibzadeh, P.

2013-01-01

73

Columbia University Varying Electron Cyclotron ResonanceVarying Electron Cyclotron Resonance  

E-print Network

matters. When one of the two sources is turned off during a discharge, the configuration evolves slowly discharge can be used to turn plasma instabilities on and off. #12;OutlineOutline Electron cyclotron current. We use a cavity heating scheme. ­ Small first-pass absorption. ­ Waves reflect from vacuum

74

In Comparative Analysis for Fuel Burnup of Fuel Assembly Designs for the 300 kW Small Medical Reactor  

SciTech Connect

A 300 kW small medical reactor was designed to be used for boron neutron capture therapy (BNCT) at KAIST in 1996. In this paper, analysis for the core life cycle of the original design of the BNCT facility and modifications of the fuel assembly configuration and enrichment to get a proper life cycle were performed and a criticality, neutron flux distribution and fuel burnup calculations were carried out.

Sambuu, Odmaa; Nanzad, Norov [Nuclear Research Center National University of Mongolia Ulaanbaatar (Mongolia)

2009-03-31

75

In Comparative Analysis for Fuel Burnup of Fuel Assembly Designs for the 300 kW Small Medical Reactor  

NASA Astrophysics Data System (ADS)

A 300 kW small medical reactor was designed to be used for boron neutron capture therapy (BNCT) at KAIST in 1996 [1]. In this paper, analysis for the core life cycle of the original design of the BNCT facility and modifications of the fuel assembly configuration and enrichment to get a proper life cycle were performed and a criticality, neutron flux distribution and fuel burnup calculations were carried out.

Sambuu, Odmaa; Nanzad, Norov

2009-03-01

76

Radioactive nuclei for medical applications  

NASA Astrophysics Data System (ADS)

The radioisotopes used for labeling the diagnostic and therapeutic radiopharmaceuticals are contemporaneously produced using neutrons in reactors and light charged particles from accelerators (cyclotrons). After the presentation of both methods the commercially available cyclotrons are reviewed. Some examples of the most popular medical radioisotopes are given. The new Radiopharmaceuticals Production and Research Centre at the University of Warsaw is presented.

Jastrz?bski, Jerzy

2011-01-01

77

Low-cost and small-sized medical microwave radiometer design  

Microsoft Academic Search

In the past decades research in microwave radiometry has been conducted for use in medical applications. Detection of breast cancer, hyperthermia, and measurment the temperature brain temperature of newborn babies are areas here this technique have been used. Russian scientists have developed a radiometer which is sold under the name of RTM-01 for the detection of breast cancer. The technical

O. Klemetsen; Y. Birkelund; S. Jacobsen

2010-01-01

78

Small Group Learning in the Final Year of a Medical Degree: A Quantitative and Qualitative Evaluation.  

ERIC Educational Resources Information Center

Explores what happens in senior medical student group sessions when students bring their own cases to the groups for discussion. Suggests that most groups run on a case-presentation and discussion format and that students want tutors to act as expert resources and be flexible in allowing students to direct the discussion. (Author/MM)

MacPherson, R.; Jones, A.; Whitehouse, C. R.; O'Neill, P. A.

2001-01-01

79

Intensity limitations in compact H{sup minus} cyclotrons  

SciTech Connect

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.

Baartman, R.A.

1995-12-31

80

COUPLER AND TRIMMER DESIGN FOR THE SCENT SUPERCONDUCTING CYCLOTRON  

Microsoft Academic Search

A superconducting cyclotron accelerating ions up to 250AMeV, for medical applications and radioactive ions production has been studied at Laboratori Nazionali del Sud in Catania (1). The radio frequency (RF) system, is based on four normal conducting radio frequency cavities operating at 93 MHz. A specific study has been done with two different 3D electromagnetic codes, Ansoft HFSS and CST

L. A. C. Piazza; D. Battaglia; L. Calabretta; A. Caruso; M. Maggiore; D. Rifuggiato

81

Development and implementation of a secure, integrated management system for medical images and electronic clinical records for small hospitals.  

PubMed

The field of Medical Informatics is currently experiencing increasing demands for new models of the Picture Archiving and Communication Systems (PACS) and Digital Imaging and Communications in Medicine (DICOM) protocols. Despite of the considerable advantages of current systems, implementation in hospitals is remarkably slow, due primarily to difficulties in integration and relatively high costs. Even though the success of DICOM standards has greatly contributed to the development of PACS, many hospitals remain unable to support it or to make full use of its potential because various imaging modalities in use at these sites generate images that cannot be stored in the PACS and cannot be managed in a centralized manner without DICOM standardization modules. Furthermore, the imaging modalities being used in such smaller centers are expensive and unlikely to be replaced, making DICOM compliance untenable. With this in mind, this paper describes the design, development, and implementation of a management system for medical diagnostic imaging, based on the DICOM standard and adapted to the needs of a small hospital. The system is currently being implemented in the San Rafael Hospital at A Coruna in Spain, and integrated with the existing hospital information system (HIS). We have studied the networking infrastructure of the hospital and its available image generation devices, and have subsequently carried out a series of measurements including transmission times, image file size, compression ratios, and many others that allow us to analyze the behavior of the system. Results obtained from these investigations demonstrate both the flexibility of using such a "small-hospital" DICOM-based framework as well as the relative cost-effectiveness of the system. In this regard, the approach, described herein, might serve as a model for other small, and possibly mid-sized, medical centers. PMID:17603833

Pereira, Javier; Castro, Antonio F; Perez, Juan L; Novoa, Francisco J; Vázquez, Jose M; Teijeiro, Jorge; Pazos, Alejandro; Ezquerra, Norberto

2007-06-01

82

Central region of SKKUCY-9 compact cyclotron  

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

83

Xe/+/ -induced ion-cyclotron harmonic waves  

NASA Astrophysics Data System (ADS)

Xenon ion sources on an ejectable package separated from the main payload during the flights of Porcupine rockets F3 and F4 which were launched from Kiruna, Sweden on March 19 and 31, 1979, respectively. The effects of the xenon ion beam, detected by the LF (f less than 16 kHz) wideband electric field experiment and analyzed by using a sonograph, are discussed. Particular attention is given to the stimulation of the ion-cyclotron harmonic waves which are usually linked to the local proton gyro-frequency, but are sometimes related to half that frequency. It was found that in a plasma dominated by O(+) ions, a small amount (1-10%) of protons could cause an effect such that the O(+) cyclotron harmonic waves are set up by the hydrogen ions, the net result being the observation of harmonic emissions separated by the hydrogen ion gyro frequency.

Jones, D.

84

Improved formulas for calculating cyclotron orbit properties  

NASA Astrophysics Data System (ADS)

Using improved techniques, analytical formulas are derived for calculating the orbit period, the radial tune, and the vertical tune as a function of energy for a given magnetic field. As examples, these formulas are applied to fields from two different machines: the three-sector K1200 superconducting cyclotron at this laboratory, and the six-sector 500 MeV cyclotron at the TRIUMF laboratory. A comparison of the results with those from a standard orbit integration program shows that the analytical formulas are, on the average, highly accurate for the orbit period, quite accurate for the radial tune, but only moderately accurate for the vertical tune. Moreover, differences between the theoretical and orbit code results are found to exhibit relatively large fluctuations which are produced by small irregularities in the measured field data.

Gordon, M. M.; Jeon, Dong-O

1991-03-01

85

New magnet pole shape for isochronous cyclotrons  

SciTech Connect

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.

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

1981-06-01

86

New magnet pole shape for isochronous cyclotrons  

SciTech Connect

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.

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

1981-01-01

87

The effect of acute medication with cilostazol, an anti-platelet drug, on the outcome of small vessel brain infarction.  

PubMed

Our objective was to investigate the effect of cilostazol in acute therapy for small vessel stroke patients. The neurologic deficits in some patients of small vessel brain infarction will progress even if a patient takes immediate medical treatments including aspirin or other antiplatelet drugs. In Japan, cilostazol, presenting not only the antiplatelet effect but also the arteriole dilation, is used for treatment of ischemic stroke. In this study, acute stroke patients with small vessel occlusion were treated with cilostazol instead of aspirin in the conventional medication after 2010. Therefore, patients between April 2007 and March 2009 were classified into the conventional group (group-con, n=220), and patients between April 2010 and March 2012 were classified into the cilostazol group (group-cilo, n=230). Enrolled patients were classified into lacunar infarction (LI) and branch atheromatous disease. Progressing stroke was defined as the increase of National Institutes of Health Stroke Scale score of 2 or more within 48 hours. The clinical outcome was assessed by the modified Rankin Scale (mRS) score at 1 month. As the result, the significant reduction in progressing stroke was dominant in the LI of brainstem (P=.01). The length of hospital stay was significantly shorter in the group-cilo compared with the group-con (18.6 and 21.2 days, P=.03). Moreover, mRS score at 1 month was significantly lower in the group-cilo than the group-con (1.9 and 2.3, P=.03). In conclusion, cilostazol reduced the risk of early neurologic deterioration of patients with small vessel brain infarction. It is eagerly desired to conduct a large randomized control trial. PMID:24513481

Nakase, Taizen; Sasaki, Masahiro; Suzuki, Akifumi

2014-07-01

88

Medical school 2.0: How we developed a student-generated question bank using small group learning.  

PubMed

Abstract Background: The multiple-choice question (MCQ) is one of the most common methods for formative and summative assessment in medical school. Common challenges with this format include (1) creating vetted questions and (2) involving students in higher-order learning activities. Involving medical students in the creation of MCQs may ameliorate both of these challenges. What we did: We used a small group learning structure to develop a student-generated question bank. Students created their own MCQ based on self-study materials, and then reviewed each other's questions within small groups. Selected questions were reviewed with the class as a whole. All questions were later vetted by the instructor and incorporated into a question bank that students could access for formative learning. Post-session survey indicated that 91% of the students felt that the class-created MCQ question bank was a valuable resource, and 86% of students would be interested in collaborating with the class for creating practice questions in future sessions. Conclusions: Developing a student-generated question bank can improve the depth and interactivity of student learning, increase session enjoyment and provide a potential resource for student assessment. PMID:25310243

Gooi, Adrian C C; Sommerfeld, Connor S

2014-10-13

89

Early clinical evaluation after aortic valve replacement with the St. Jude Medical valve in patients with a small aortic root.  

PubMed

Forty-three patients, nine men and 34 women, mean age 60 years (range 23-81 years), who had small aortic roots underwent aortic valve replacement with a St. Jude Medical valve. Preoperatively, five patients were in New York Heart Association (NYHA) class I, 19 were in class II, 15 were in class III and four were in class IV. In 30 of 36 patients with aortic stenosis, the mean gradient was 102 mm Hg (range 52-175 mm Hg; in six patients with aortic stenosis, the gradient was not measured. Seven patients underwent surgery for aortic regurgitation. Ten patients received a 19-mm valve, 29 a 21-mm valve and nine a 23-mm valve. Two patients (4.6%) died in the hospital, one immediately postoperatively and the other from low cardiac output 9 days postoperatively. There are 670 patient-months of follow-up (mean 17 months). Thirty-six patients are NYHA class I and two patients are in class II. There have been no thromboembolic episodes in 605 months of follow-up for patients maintained on warfarin. There was one partial valve thrombosis among eight patients being managed without warfarin. No mechanical valve failures have occurred. The St. Jude Medical valve provides a satisfactory early result when used to replace the aortic valve of patients who have a small aortic root. PMID:7083534

Gill, C C; King, H C; Lytle, B W; Cosgrove, D M; Golding, L A; Loop, F D

1982-08-01

90

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

Microsoft Academic Search

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

David E. C.. Rogers; Alan C. Brent

2006-01-01

91

3D Observations of Electromagnetic Ion Cyclotron Wave Propagation in a Laboratory Plasma Column  

E-print Network

3D Observations of Electromagnetic Ion Cyclotron Wave Propagation in a Laboratory Plasma Column The propagation of Electromagnetic Ion Cyclotron Waves (EMICW's) as launched by an antenna of small transverse meter in diameter, 10 meters long, surrounded by 68 pancake electromagnets. The helium plasma column

California at Los Angles, University of

92

Ion cyclotron resonance cell  

DOEpatents

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.

Weller, Robert R. (Aiken, SC)

1995-01-01

93

Cyclotron targets and production technologies used for radiopharmaceuticals in NPI  

NASA Astrophysics Data System (ADS)

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.

Fišer, M.; Kopi?ka, K.; Hradilek, P.; Han?, P.; Lebeda, O.; Pánek, J.; Vognar, M.

2003-01-01

94

Backward radiation from a horseshoe type cyclotron instability  

NASA Astrophysics Data System (ADS)

Recent observations of Auroral Kilometric Radiation produced by a beam-driven cyclotron instability suggest that it is generated at a small angle to perpendicular in the backward direction with respect to the beam. New data also suggest backward propagation of cyclotron radiation from some stars with dipole magnetic field. Our experiment at the University of Strathclyde investigating cyclotron maser emission similar to AKR also showed that the fastest growing wave is propagating backward, with this result confirmed by simulations and analytic calculations of the growth rate. We propose here a possible explanation of this phenomenon. The instability is driven by a population inversion of the electron distribution in the perpendicular direction and for different directions of propagation slightly away from perpendicular the cyclotron resonance curve passes through the region of maximum gradient for different frequencies. Near cyclotron resonance the real part of the dispersion relation is strongly frequency dependent. We show that this leads to the conclusion that the peak growth would be expected for a small backward angle, in line with the results of observation and simulation.

Vorgul, Irena; Kellett, Barry J.; Cairns, R. A.; Bingham, Robert; Ronald, Kevin; Speirs, David C.; McConville, Sandra; Gillespie, Karen; Phelps, Alan D. R.

2012-10-01

95

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

PubMed Central

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

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

2015-01-01

96

ECR (Electron Cyclotron Resonance) ion sources for cyclotrons  

SciTech Connect

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.

Lyneis, C.M.

1986-10-01

97

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

SciTech Connect

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).

Prater, R.; Lohr, J. [eds.

1985-12-31

98

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

Microsoft Academic Search

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

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

2011-01-01

99

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

Microsoft Academic Search

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

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

2010-01-01

100

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

NASA Astrophysics Data System (ADS)

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 e?A of C5+ ion beam should be extracted from the ion source, and the beam emittance better than 75 ?*mm*mrad. In recent commissioning, about 120 e?A of C5+ ion beam was got when work gas was CH4 while about 262 e?A 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.

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

101

Cyclotron and linac production of Ac-225.  

PubMed

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

Melville, Graeme; Allen, Barry J

2009-04-01

102

Use of Modified SOAP Notes and Peer-led Small-group Discussion in a Medical Physiology Course: Addressing the Hidden Curriculum  

NSDL National Science Digital Library

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

PhD Jonathan Kibble (St. George's University Department of Physiology and Neuroscience); PhD Penelope Hansen (Memorial University Basic Science Division); Loren Nelson (St. George's University Department of Physiology and Neuroscience)

2006-12-01

103

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

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…

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

2006-01-01

104

'I take a small amount of the real product': Elevated cholesterol and everyday medical reasoning in liminal space.  

PubMed

The medical consequences of elevated cholesterol are widely known, as are the medical regimens to control and manage it. At the same time, elevated cholesterol is bereft of bodily signs. Being symptomless places the condition in a no man's land: people with elevated cholesterol are assessed as medically sick but their bodies signal wellness. In this article I refer to this ambiguous grey area, betwixt and between being healthy and being sick, as liminal space . The aim of this article is to show how people manage the symptomless condition of elevated cholesterol in liminal space. Particular attention is paid to everyday medical reasoning in that space. Based on interviews with people with elevated cholesterol, I show that medical regimens are 'up against' - challenged by - a variety of competing conditions in everyday life, illustrating ambiguity. Facing this dilemma between medicine and everyday life, they ongoingly need to navigate - edit, modify, adjust - medical regimens against everyday conditions. This navigating work can be seen as ritualized strategies to sort ambiguity. People with elevated cholesterol do not so much act 'against medical regimens' as they simultaneously need to take account of other matters they are up against in trying to stay healthy. Medical regimens are sometimes central, sometimes peripheral. Adapting medical regimens to the situation at hand, people continuously comply with medical regimens, producing and reproducing medical regimens in moral contexts of everyday life. PMID:21177710

Hoel Felde, Lina Klara

2011-11-01

105

Electron cyclotron harmonic wave acceleration  

NASA Technical Reports Server (NTRS)

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.

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

1987-01-01

106

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

PubMed Central

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

2012-01-01

107

High brightness 50 MeV Cyclotron for Accelerator-Driven Subcritical Fission  

NASA Astrophysics Data System (ADS)

The Accelerator Research Lab at Texas A&M University is developing new accelerator technology for a high-brightness, high-current cyclotron with capabilities that will be beneficial for applications to accelerator-driven subcritical fission, medical isotope production, and proton therapy. As a first embodiment of the technology, we are developing a detailed design for TAMU-50, a 50 MeV, 5 mA proton cyclotron with high beam brightness. In this presentation we present devices and beamline components for injection, extraction, controls and diagnostics. We emphasize the system integration and implementation of TAMU-50 for production of medical radioisotopes.

Assadi, Saeed; Badgley, Karie; Mann, Thomas; McIntyre, Peter; Pogue, Nathaniel; Sattarov, Akhdiyor

2011-10-01

108

The cyclotron laboratory and the RFQ accelerator in Bern  

SciTech Connect

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.

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

2013-07-18

109

The cyclotron laboratory and the RFQ accelerator in Bern  

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

110

Cyclotron Production of Technetium-99m  

NASA Astrophysics Data System (ADS)

Technetium-99m (99mTc) has emerged as the most widely used radionuclide in medicine and is currently obtained from a 99Mo/ 99mTc generator system. At present, there are only a handful of ageing reactors worldwide capable of producing large quantities of the parent isotope, 99Mo, and owing to the ever growing shutdown periods for maintenance and repair of these ageing reactors, the reliable supply 99mTc has been compromised in recent years. With an interest in alternative strategies for producing this key medical isotope, this thesis focuses on several technical challenges related to the direct cyclotron production of 99mTc via the 100Mo(p,2n)99mTc reaction. In addition to evaluating the 100Mo(p,2n)99mTc and 100Mo(p,x)99Mo reactions, this work presented the first experimental evaluation of the 100Mo(p,2n) 99gTc excitation function in the range of 8-18 MeV. Thick target calculations suggested that large quantities of cyclotron-produced 99mTc may be possible. For example, a 6 hr irradiation at 500 ?A with an energy window of 18?10 MeV is expected to yield 1.15 TBq of 99mTc. The level of coproduced 99gTc contaminant was found to be on par with the current 99Mo/99mTc generator standard eluted with a 24 hr frequency. Highly enriched 100Mo was required as the target material for 99mTc production and a process for recycling of this expensive material is presented. An 87% recovery yield is reported, including metallic target preparation, irradiation, 99mTc extraction, molybdate isolation, and finally hydrogen reduction to the metal. Further improvements are expected with additional optimization experiments. A method for forming structurally stable metallic molybdenum targets has also been developed. These targets are capable of withstanding more than a kilowatt of beam power and the reliable production and extraction of Curie quantities of 99mTc has been demonstrated. With the end-goal of using the cyclotron-produced 99mTc clinically, the quality of the cyclotron-produced 99mTc has been extensively compared with relevant United States Pharmacopeia (USP) specifications for the existing 99Mo/99mTc production strategy. Additional quality testing, including biodistribution studies of [ 99mTc]pertechnetate and [99mTc]disofenin in both mice and rabbits was also evaluated. Using the strategies and results presented throughout this dissertation, this thesis concludes with the world's first cyclotron-based 99mTc patient images obtained as part of a Phase I Clinical Trial at the University of Alberta using [99m Tc]pertechnetate.

Gagnon, Katherine M.

111

Production of the PET bone agent (18)F-fluoride ion, simultaneously with (18)F-FDG by a single run of the medical cyclotron with minimal radiation exposure- a novel technique.  

PubMed

Our aim was to establish an easy and convenient procedure for the preparation of fluorine-18-sodium fluoride ((18)F-NaF) for bone positron emission tomography (PET) during routine (18)F-FDG production using the Explora FDG4 radiochemistry module (EFRM) by single run of Cyclotron with negligible radiation exposure. We compared three techniques for (18)F-NaF production during routine PET radiochemistry at our setup. In one method we used synthesis module and in other two methods we did not. In the first and third method, F-18 was directly extracted from the V-vial and in the second method, (18)F-NaF was extracted by post processing from the EFRM. In the first method, F-18 was extracted directly from V-vial manually by opening the V-vial cap. In the second method, Explora FDG-4 Module was used. First, F-18 was transferred from the V-vial. Then, after post processing in EFRM, pure F-18 was obtained in the product vial. In the third method, pure F-18 was obtained in the product vial with the help of a mechanical robotic arm. The above were followed by routine quality control of (18)F-NaF produced by each method. Results of quality control of the (18)F-NaF obtained by all three methods satisfied all parameters prescribed by the United States Pharmacopeia (USP) and the British Pharmacopeia (BP) including biological, physical and chemical specifications. The radiochemical purity was 98.5±1.5% with Rf 0.006. The level of Kryptofix-222 (K222) in (18)F-NaF was within the prescribed limit. Mean pH of (18)F-NaF was 6.0±1.5. The exposure rate around the hot cell was negligible. In conclusion, from the results it was obvious that by our method number three (18)F-NaF was directly obtained from the V-vial using mechanical robotic arms. This method was the most appropriate with minimized radiation exposure to the handling Radiochemist and was also saving time as compared to the other two methods. PMID:25097896

Kumar, Rajeev; Sonkawade, Rajendra G; Tripathi, Madhavi; Sharma, Punit; Gupta, Priyanka; Kumar, Praveen; Pandey, Anil K; Bal, Chandrasekhar; Damle, Nishikant Avinash; Bandopadhayaya, Gurupad

2014-01-01

112

TRIUMF cyclotron vacuum system refurbishing  

NASA Astrophysics Data System (ADS)

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.

Sekachev, I.

2008-03-01

113

Method and apparatus for ion cyclotron spectrometry  

DOEpatents

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.

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

2010-08-17

114

Electron cyclotron resonance ion sources in use for heavy ion cancer therapy  

Microsoft Academic Search

The use of electron cyclotron resonance (ECR) ion sources for producing ion beams for heavy ion cancer therapy has been established for more than ten years. After the Heavy Ion Medical Accelerator (HIMAC) at Chiba, Japan started therapy of patients with carbon ions in 1994 the first carbon ion beam for patient treatment at the accelerator facility of GSI was

K. Tinschert; R. Iannucci; R. Lang

2008-01-01

115

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

ERIC Educational Resources Information Center

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…

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

2012-01-01

116

The theory of relativistic cyclotron resonance maser amplifiers  

NASA Astrophysics Data System (ADS)

So that a relativistic electron can yield all its kinetic energy to the electromagnetic wave under cyclotron resonance conditions, the difference between the wave phase velocity and the speed of light must be small, as must be the ratio of the initial transverse velocity to the longitudinal velocity of the electron. Taking these conditions into account, equations are derived and analyzed, which describe a relativistic cyclotron resonance maser (CRM) with a following wave for arbitrary particle energy and a wave phase velocity. A linear theory is constructed and the nonlinear characteristics of the relativistic CRM amplifiers with TWT and twistron type following waves are examined. It is shown that the efficiency of the ultrarelativistic CRM with the following wave, in the large frequency conversion regime, can exceed 30%.

Ginzburg, N. S.; Zarnitsyna, I. G.; Nusinovich, G. S.

117

Achieving Small Structures in Thin NiTi Sheets for Medical Applications with Water Jet and Micro Machining: A Comparison  

Microsoft Academic Search

NiTi shape memory alloys (SMA) are used for a variety of applications including medical implants and tools as well as actuators,\\u000a making use of their unique properties. However, due to the hardness and strength, in combination with the high elasticity\\u000a of the material, the machining of components can be challenging. The most common machining techniques used today are laser\\u000a cutting

M. Frotscher; F. Kahleyss; T. Simon; D. Biermann; G. Eggeler

2011-01-01

118

Lawrence's Legacy : Seaborg's Cyclotron - The 88-Inch Cyclotron turns 40  

NASA Astrophysics Data System (ADS)

In 1958, Sputnik had recently been launched by the Russians, leading to worry in Congress and increased funding for science and technology. Ernest Lawrence was director of the "Rad Lab" at Berkeley. Another Nobel Prize winner, Glenn Seaborg, was Associate Laboratory Director and Director of the Nuclear Chemistry Division. In this atmosphere, Lawrence was phoned by commissioners of the Atomic Energy Commission and asked what they could do for Seaborg, "because he did such a fine job of setting up the chemistry for extracting plutonium from spent reactor fuel" [1]. In this informal way, the 90-Inch (eventually 88-Inch) Cyclotron became a line item in the federal budget at a cost of 3M (later increased to 5M). The 88-Inch Cyclotron achieved first internal beam on Dec. 12, 1961 and first external beam in May 1962. Forty years later it is still going strong. Pieced together from interviews with the retirees who built it, Rad Lab reports and archives from the Seaborg and Lawrence collections, the story of its design and construction - on-time and under-budget - provides a glimpse into the early days of big science. [1] remarks made by Elmer Kelly, "Physicist-in-charge' of the project on the occasion of the 40th anniversary celebration.

McMahan, Margaret; Clark, David

2003-04-01

119

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

PubMed

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

Hourd, P C; Williams, D J

2008-07-01

120

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

SciTech Connect

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.

Nakayama, Hidetsugu, E-mail: hnakayama@pmrc.tsukuba.ac.j [Proton Medical Research Center, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki (Japan); Department of Radiation Oncology, Tsukuba Medical Center, Ibaraki (Japan); Sugahara, Shinji [Proton Medical Research Center, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki (Japan); Tokita, Mari [Department of Radiation Oncology, Alpert Medical School of Brown University, Providence, RI (United States); Satoh, Hiroaki [Department of Respiratory Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki (Japan); Tsuboi, Koji [Proton Medical Research Center, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki (Japan); Ishikawa, Shigemi [Department of Thoracic Surgery, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki (Japan); Tokuuye, Koichi [Department of Radiation Oncology, Tsukuba Medical Center, Ibaraki (Japan); Department of Radiology, Tokyo Medical University, Shinjuku, Tokyo (Japan)

2010-10-01

121

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

NASA Astrophysics Data System (ADS)

A 12.5 MeV, 25 ?A, 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.

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

2014-11-01

122

A high resolution Small Field Of View (SFOV) gamma camera: a columnar scintillator coated CCD imager for medical applications  

NASA Astrophysics Data System (ADS)

We describe a high resolution, small field of view (SFOV), Charge Coupled Device (CCD) based camera for imaging small volumes of radionuclide uptake in tissues. The Mini Gamma Ray Camera (MGRC) is a collimated, scintillator-coated, low cost, high performance imager using low noise CCDs. The prototype MGRC has a 600 ?m thick layer of columnar CsI(Tl) and operates in photon counting mode using a thermoelectric cooler to achieve an operating temperature of - 10°C. Collimation was performed using a pin hole collimator. We have measured the spatial resolution, energy resolution and efficiency using a number of radioisotope sources including 140 keV gamma-rays from 99mTc in a specially designed phantom. We also describe our first imaging of a volunteer patient.

Lees, J. E.; Bassford, D. J.; Blake, O. E.; Blackshaw, P. E.; Perkins, A. C.

2011-12-01

123

Electron cyclotron resonance plasma photos  

SciTech Connect

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.

Racz, R.; Palinkas, J. [Institute of Nuclear Research (ATOMKI), H-4026 Debrecen, Bem ter 18/c (Hungary); University of Debrecen, H-4010 Debrecen, Egyetem ter 1 (Hungary); Biri, S. [Institute of Nuclear Research (ATOMKI), H-4026 Debrecen, Bem ter 18/c (Hungary)

2010-02-15

124

Relativistic electromagnetic ion cyclotron instabilities.  

PubMed

The relativistic instabilities of electromagnetic ion cyclotron waves driven by MeV ions are analytically and numerically studied. As caused by wave magnetic field and in sharp contrast to the electrostatic case, interesting characteristics such as Alfve nic behavior and instability transition are discovered and illuminated in detail. The instabilities are reactive and are raised from the coupling of slow ions' first-order resonance and fast ions' second-order resonance, that is an essential extra mechanism due to relativistic effect. Because of the wave magnetic field, the nonresonant plasma dielectric is usually negative and large, that affects the instability conditions and scaling laws. A negative harmonic cyclotron frequency mismatch between the fast and slow ions is required for driving a cubic (and a coupled quadratic) instability; the cubic (square) root scaling of the peak growth rate makes the relativistic effect more important than classical mechanism, especially for low fast ion density and Lorentz factor being close to unity. For the cubic instability, there is a threshold (ceiling) on the slow ion temperature and density (the external magnetic field and the fast ion energy); the Alfve n velocity is required to be low. This Alfve nic behavior is interesting in physics and important for its applications. The case of fast protons in thermal deuterons is numerically studied and compared with the analytical results. When the slow ion temperature or density (the external magnetic field or the fast ion energy) is increased (reduced) to about twice (half) the threshold (ceiling), the same growth rate peak transits from the cubic instability to the coupled quadratic instability and a different cubic instability branch appears. The instability transition is an interesting new phenomenon for instability. PMID:15903591

Chen, K R; Huang, R D; Wang, J C; Chen, Y Y

2005-03-01

125

All-magnetic extraction for cyclotron beam reacceleration  

DOEpatents

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)

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

1975-07-22

126

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

PubMed Central

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, RBE) at 2.5 Gy/fraction in this phase I/II study. All patients underwent treatment simulation with 4-dimensional (4D) computed tomography (CT); internal gross tumor volumes (iGTVs) were delineated on maximal intensity projection (MIP) images and modified by visual verification of the target volume in 10 breathing phases. The iGTV with MIP density was used to design compensators and apertures to account for tumor motion. Therapy consisted of passively scattered protons. All patients underwent repeat 4D 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. PMID:21251767

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

2011-01-01

127

Method and apparatuses for ion cyclotron spectrometry  

DOEpatents

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.

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

2012-03-06

128

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

SciTech Connect

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 e?A of C{sup 5+} ion beam should be extracted from the ion source, and the beam emittance better than 75 ?*mm*mrad. In recent commissioning, about 120 e?A of C{sup 5+} ion beam was got when work gas was CH{sub 4} while about 262 e?A 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.

Cao, Yun, E-mail: caoyun@impcas.ac.cn; Li, Jia Qing; Sun, Liang Ting; Zhang, Xue Zhen; Feng, Yu Cheng; Wang, Hui; Ma, Bao Hua; Li, Xi Xia [Institute of Modern Physics, CAS, Lanzhou 730000 (China)] [Institute of Modern Physics, CAS, Lanzhou 730000 (China)

2014-02-15

129

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

PubMed

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 e?A of C(5+) ion beam should be extracted from the ion source, and the beam emittance better than 75 ?*mm*mrad. In recent commissioning, about 120 e?A of C(5+) ion beam was got when work gas was CH4 while about 262 e?A of C(5+) 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. PMID:24593539

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

130

IMPROVEMENTS TO THE ITHEMBA LABS CYCLOTRON FACILITIES  

Microsoft Academic Search

At iThemba LABS a K200 separated-sector cyclotron and its two K8 injector cyclotrons accelerate beams of light and heavy ions as well as polarized hydrogen ions to variable energies for nuclear physics research. For proton therapy a 200 MeV proton beam is used. For neutron therapy and radioisotope production a 66 MeV proton beam is available. The latest development work

J. L. Conradie; P. J. Celliers; J. G. de Villiers; J. L. G. Delsink; R. E. F. Fenemore; D. T. Fourie; I. H. Kohler; C. Lussi; P. T. Mansfield; H. Mostert; G. S. Muller; P. F. Rohwer; M. Sakildien; R. W. Thomae; M. J. van Niekerk; P. A. van Schalkwyk

131

The Cyclotron Production and Nuclear Imaging of BROMINE-77.  

NASA Astrophysics Data System (ADS)

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.

Galiano, Eduardo

132

Electrostatic ion cyclotron, beam-plasma, and lower hybrid waves excited by an electron beam  

NASA Astrophysics Data System (ADS)

It is pointed out that electrostatic ion cyclotron (EIC) waves have been extensively investigated in connection with both space and laboratory plasmas. The present investigation has the objective to study the excitation of low-frequency waves in a multiion plasma by electron beams. The frequencies considered range from below the lowest gyrofrequency of the heaviest ion to about the lower hybrid frequency. It is shown that electron-beam instabilities can produce peaks in the growth rate below the cyclotron frequency of each ion species if nonzero perpendicular wave number effects are included in the ion dynamics. The dispersion relations for neutralized ion Bernstein (NIB) and pure ion Bernstein (PIB) waves are considered along with an instability analysis for a cold plasma and warm electron beam, the electron beam-plasma mode, banded ion cyclotron (EIC) waves with small perpendicular wavelengths, and the growth lengths of the waves.

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

1985-06-01

133

On the electrically detected cyclotron resonance of holes in silicon nanostructures  

SciTech Connect

The cyclotron resonance in semiconductor nanostructures is electrically detected for the first time without an external cavity, a source, and a detector of microwave radiation. An ultranarrow p-Si quantum well on an n-Si (100) surface confined by superconducting heavily boron-doped {delta}-shaped barriers is used as the object of investigation and provides microwave generation within the framework of the nonstationary Josephson effect. The cyclotron resonance is detected upon the presence of a microcavity, which is incorporated into the quantum-well plane, by measuring the longitudinal magnetoresistance under conditions of stabilization of the source-drain current. The cyclotron-resonance spectra and their angular dependences measured in a low magnetic field identify small values of the effective mass of light and heavy holes in various 2D subbands due to the presence of edge channels with a high mobility of carriers.

Bagraev, N. T., E-mail: bagraev@mail.ioffe.ru; Gets, D. S.; Danilovsky, E. Yu.; Klyachkin, L. E.; Malyarenko, A. M. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

2013-04-15

134

Oak Ridge Isotope Production Cyclotron Facility and Target Handling  

SciTech Connect

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.

Bradley, Eric Craig [ORNL; Varma, Venugopal Koikal [ORNL; Egle, Brian [ORNL; Binder, Jeffrey L [ORNL; Mirzadeh, Saed [ORNL; Tatum, B Alan [ORNL; Burgess, Thomas W [ORNL; Devore, Joe [Oak Ridge National Laboratory (ORNL); Rennich, Mark [Oak Ridge National Laboratory (ORNL); Saltmarsh, Michael John [ORNL; Caldwell, Benjamin Cale [Oak Ridge National Laboratory (ORNL)

2011-01-01

135

a Low Energy Cyclotron for Radiocarbon Dating  

NASA Astrophysics Data System (ADS)

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 ('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 ('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 ('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 sample changing to make radiocarbon dating milligram samples with a modest laboratory instrument feasible.

Welch, James Joseph

136

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

SciTech Connect

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.

Allibhai, Zishan [Department of Radiation Oncology, Princess Margaret Cancer Centre, Toronto (Canada); Taremi, Mojgan [Department of Radiation Oncology, Stronach Regional Cancer Centre, Newmarket (Canada); Bezjak, Andrea; Brade, Anthony; Hope, Andrew J.; Sun, Alexander [Department of Radiation Oncology, Princess Margaret Cancer Centre, Toronto (Canada); Cho, B.C. John, E-mail: john.cho@rmp.uhn.on.ca [Department of Radiation Oncology, Princess Margaret Cancer Centre, Toronto (Canada)

2013-12-01

137

Improving cancer treatment with cyclotron produced radionuclides  

SciTech Connect

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.

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

1992-08-04

138

Cyclotron maser emission: Stars, planets, and laboratory  

NASA Astrophysics Data System (ADS)

This paper is a review of results by the group over the past decade on auroral kilometric radiation and similar cyclotron emissions from stars and planets. These emissions are often attributed to a horseshoe or crescent shaped momentum distribution of energetic electrons moving into the convergent magnetic field which exists around polar regions of dipole-type stars and planets. We have established a laboratory-based facility that has verified many of the details of our original theoretical description and agrees well with numerical simulations. The experiment has demonstrated that the horseshoe distribution does indeed produce cyclotron emission at a frequency just below the local cyclotron frequency, with polarization close to X-mode and propagating nearly perpendicularly to the beam motion. We discuss recent developments in the theory and simulation of the instability including addressing a radiation escape problem and the effect of competing instabilities, relating these to the laboratory, space, and astrophysical observations.

Vorgul, I.; Kellett, B. J.; Cairns, R. A.; Bingham, R.; Ronald, K.; Speirs, D. C.; McConville, S. L.; Gillespie, K. M.; Phelps, A. D. R.

2011-05-01

139

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

PubMed Central

Background The study was designed to evaluate the effects of moderate prosthesis-patient mismatch (defined as 0.65 cm2/m2?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?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

2014-01-01

140

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

SciTech Connect

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.

Efremov, A., E-mail: efremov@nrmail.jinr.ru; Bogomolov, S.; Lebedev, A.; Loginov, V.; Yazvitsky, N. [Joint Institute for Nuclear Research, Flerov Laboratory of Nuclear Reactions, Dubna, Moscow Reg. 141980 (Russian Federation)] [Joint Institute for Nuclear Research, Flerov Laboratory of Nuclear Reactions, Dubna, Moscow Reg. 141980 (Russian Federation)

2014-02-15

141

Design and testing of an electron cyclotron resonance heating ion source for use in high field compact superconducting cyclotrons  

E-print Network

The main goal of this project is to evaluate the feasibility of axial injection of a high brightness beam from an Electron Cyclotron Resonance ion source into a high magnetic field cyclotron. Axial injection from an ion ...

Artz, Mark E

2012-01-01

142

Relativistic Dispersion, the Cyclotron Maser Instability, and Auroral Kilometric Radiation  

Microsoft Academic Search

The most successful explanation proposed for the generation of auroral kilometric radiation (AKR) is the direct cyclotron mechanism in which radiation excited near the local electron cyclotron frequency is amplified through a gyroresonant interaction. Previous work has shown that inclusion of the relativistic mass dependence of the cyclotron frequency is essential to determine the resonant contours in velocity space. In

P. L. Pritchett

1984-01-01

143

Transmission characteristics of cyclotron harmonic waves in plasma  

Microsoft Academic Search

In recent years the importance of cyclotron harmonic waves has become apparent in many branches of plasma physics. For example, it has been demonstrated that they are involved in the anomalously high noise radiation near the electron cyclotron harmonic frequencies that has been observed from thermonuclear fusion study devices, and that they can explain the cyclotron harmonic resonances observed in

F. W. Crawford; H. H. Weiss

1966-01-01

144

Michigan State University National Superconducting Cyclotron Laboratory  

E-print Network

Michigan State University National Superconducting Cyclotron Laboratory East Lansing, Michigan USA (University of Manchester, UK) Joseph CARLSON (Los Alamos National laboratory, USA) Mark DYKMAN (Michigan Lectureship Endowment at Michigan State University Please register by contacting lesliel@nscl.msu.edu The main

Yannouleas, Constantine

145

On Resonant Heating Below the Cyclotron Frequency  

SciTech Connect

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.

Liu Chen; Zhihong Lin; White, R.

2001-02-02

146

Cyclotron-based neutron source for BNCT  

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

147

Numerical investigation of auroral cyclotron maser processesa)  

NASA Astrophysics Data System (ADS)

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.

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

2010-05-01

148

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

NASA Astrophysics Data System (ADS)

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 ?A. A target current of 100 ?A 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 120?A.

Bergstrom, Jan Olof; Eriksson, Tomas

2003-08-01

149

High Radiation Dose May Reduce the Negative Effect of Large Gross Tumor Volume in Patients With Medically Inoperable Early-Stage Non-Small Cell Lung Cancer  

SciTech Connect

Purpose: To determine whether the effect of radiation dose varies with gross tumor volume (GTV) in patients with stage I/II non-small cell lung cancer (NSCLC). Methods and Materials: Included in the study were 114 consecutive patients with medically inoperable stage I/II NSCLC treated with three-dimensional conformal radiotherapy between 1992 and 2004. The median biologic equivalent dose (BED) was 79.2 Gy (range, 58.2-124.5 Gy). The median GTV was 51.8 cm{sup 3} (range, 2.1-727.8 cm{sup 3}). The primary endpoint was overall survival (OS). Kaplan-Meier estimation and Cox regression models were used for survival analyses. Results: Multivariate analysis showed that there was a significant interaction between radiation dose and GTV (p < 0.001). In patients with BED {<=}79.2 Gy (n = 68), the OS medians for patients with GTV >51.8 cm{sup 3} and {<=}51.8 cm{sup 3} were 18.2 and 23.9 months, respectively (p 0.015). If BED was >79.2 Gy (n = 46), no significant difference was found between GTV groups (p = 0.681). For patients with GTV >51.8 cm{sup 3} (n = 45), the OS medians in those with BED >79.2 Gy and {<=}79.2 Gy were 30.4 and 18.2 months, respectively (p < 0.001). If GTV was {<=}51.8 cm{sup 3} (n = 45), the difference was no longer significant (p = 0.577). Conclusion: High-dose radiation is more important for patients with larger tumors and may be effective in reducing the adverse outcome associated with large GTV. Further prospective studies are needed to confirm this finding.

Zhao Lujun [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, MI (United States); West, Brady T. [Center for Statistical Consultation and Research, University of Michigan Medical Center, Ann Arbor, MI (United States); Hayman, James A. [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, MI (United States); Lyons, Susan [Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI (United States); Department of Radiation Oncology, Veterans Administration Health Center, Ann Arbor, MI (United States); Cease, Kemp [Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI (United States); Department of Radiation Oncology, Veterans Administration Health Center, Ann Arbor, MI (United States); Kong, F.-M. [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, MI (United States) and Department of Radiation Oncology, Veterans Administration Health Center, Ann Arbor, MI (United States)]. E-mail: Fengkong@med.umich.edu

2007-05-01

150

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

SciTech Connect

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.

Louie, Alexander V. [Department of Oncology, University of Western Ontario, London, ON (Canada); Rodrigues, George, E-mail: george.rodrigues@lhsc.on.ca [Department of Oncology, University of Western Ontario, London, ON (Canada); Department of Epidemiology/Biostatistics, University of Western Ontario, London, ON (Canada); Hannouf, Malek [Department of Epidemiology/Biostatistics, University of Western Ontario, London, ON (Canada); Zaric, Gregory S. [Department of Epidemiology/Biostatistics, University of Western Ontario, London, ON (Canada); Richard Ivey School of Business, University of Western Ontario, London, ON (Canada); Palma, David A. [Department of Oncology, University of Western Ontario, London, ON (Canada); Cao, Jeffrey Q. [Department of Oncology, University of Western Ontario, London, ON (Canada); Richard Ivey School of Business, University of Western Ontario, London, ON (Canada); Yaremko, Brian P. [Department of Oncology, University of Western Ontario, London, ON (Canada); Malthaner, Richard [Department of Epidemiology/Biostatistics, University of Western Ontario, London, ON (Canada); Division of Surgery, University of Western Ontario, London, ON (Canada); Mocanu, Joseph D. [Richard Ivey School of Business, University of Western Ontario, London, ON (Canada)

2011-11-15

151

Design study of a 9 MeV compact cyclotron system for PET  

NASA Astrophysics Data System (ADS)

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.

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

2013-06-01

152

Space Charge Frequency Shifts of the Cyclotron Modes in Multi-Species Ion Plasmas.  

PubMed

Shifts of the cyclotron frequency away from the "bare" cyclotron frequency are observed to be proportional to the total ion density through the E?×?B rotation frequency, and to the relative concentration of each ion species, in quantitative agreement with analytic theory. These shifts are measured at small excitation amplitudes on the typical center-of-mass m?=?1 mode, and also on cyclotron modes with m?=?0 and m?=?2 azimuthal dependence. The frequency spacing between these modes is proportional to the rotation frequency of the ion cloud, which is controlled and measured using a "rotating wall" and laser-induced fluorescence. These cylindrical ion plasmas consist of Mg(+) isotopes, with H3 O (+) and O2 (+) impurities. It is observed that the shift in the m?=?1 cyclotron frequency is larger for the minority species (25)Mg(+) and (26)Mg(+), than for the majority species (24)Mg(+). A simple center-of-mass model is presented, which is in quantitative agreement with these results. It is also shown that this model interprets and expands the intensity dependent calibration equation, (M/q)?=?A/f?+?B/f (2)?+?CI/f (2). PMID:25450158

Affolter, M; Anderegg, F; Driscoll, C F

2014-12-01

153

Electron-cyclotron wave scattering by edge density fluctuations in ITER  

SciTech Connect

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.

Tsironis, Christos [School of Electrical and Computer Engineering, National Technical University of Athens, Athens GR 15773 (Greece); Department of Physics, Aristotle University of Thessaloniki, Thessaloniki GR 54006 (Greece); Peeters, Arthur G. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Isliker, Heinz; Chatziantonaki, Ioanna; Vlahos, Loukas [Department of Physics, Aristotle University of Thessaloniki, Thessaloniki GR 54006 (Greece); Strintzi, Dafni [School of Electrical and Computer Engineering, National Technical University of Athens, Athens GR 15773 (Greece)

2009-11-15

154

Electrostatic ion cyclotron velocity shear instability  

NASA Technical Reports Server (NTRS)

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).

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

1992-01-01

155

The mirror and ion cyclotron anisotropy instabilities  

NASA Astrophysics Data System (ADS)

The linear dispersion equation for fully electromagnetic waves and instabilities at arbitrary directions of propagation relative to a background magnetic field B(0) in a homogeneous Vlasov plasma is solved numerically for bi-Maxwellian particle distributions. For isotropic plasmas the dispersion and damping of the three modes below the proton cyclotron frequency are studied as functions of Beta(i) and T(e)/T(i). The transport ratios of helicity, cross-helicity, Alfven ratio, compressibility, and parallel compressibility are defined. Under the condition that the proton temperature perpendicular to B(0) is greater than the parallel temperature, the growth rates and transport ratios of the mirror instability and the ion cyclotron anisotropy instability are examined and compared. Both the proton parallel compressibility and the proton Alfven ratio are significantly different for the two growing modes.

Gary, S. P.

1992-06-01

156

Radical radiotherapy for stage I/II non-small cell lung cancer in patients not sufficiently fit for or declining surgery (medically inoperable): a systematic review  

PubMed Central

OBJECTIVES—To determine the effectiveness of radical radiotherapy in medically inoperable stage I/II non-small cell lung cancer (NSCLC) and the extent of treatment related morbidity.?METHODS—Randomised trials were sought by electronically searching the Cochrane Clinical Trials Register, and both randomised and non-randomised trials were sought by searching Medline and Excerpta Medica (Embase). Further studies were identified from references cited in those papers already identified by electronic searching. The studies included were those of patients of any age with stage I/II NSCLC receiving radiotherapy at a dose of >40 Gy in 20 fractions over 4 weeks or its radiobiological equivalent.?RESULTS—Two randomised and 35 non-randomised studies were identified. One randomised and nine non-randomised studies did not meet the selection criteria, leaving one randomised and 26 non-randomised studies for analysis. In the randomised trial 2 year survival was higher following continuous hyperfractionated accelerated radiotherapy (CHART; 37%) than following 60 Gy in 30 fractions over 6 weeks (24%). An estimated 2003 patients were included in the 26 non-randomised studies; overall survival was 22-72% at 2 years, 17-55% at 3 years, and 0-42% at 5 years. Following treatment, 11-43% of patients died from causes other than cancer. Cancer specific survival was 54-93% at 2 years, 22-56% at 3 years, and 13-39% at 5 years. Complete response rates were 33-61% and local failure rates were 6-70%. Distant metastases developed in approximately 25% of patients. Better response rates and survival were seen in those with smaller tumours and in those receiving higher doses although the reasons for prescribing higher doses were not clearly stated. The outcome was worse in those with prior weight loss or poor performance status. Assessment of treatment related morbidity and effects on quality of life and symptom control were inconclusive because of the lack of prospective evaluation and paucity of data.?CONCLUSIONS—No randomised trials compared a policy of immediate radical radiotherapy with palliative radiotherapy given when patients develop symptoms. In the absence of such trials, radical radiotherapy appears to result in a better survival than might be expected had treatment not been given. A substantial, though variable, proportion of patients died during follow up from causes other than cancer. The optimal radiation dose and treatment technique (particularly with respect to mediastinal irradiation) remain uncertain.?? PMID:11462066

Rowell, N; Williams, C

2001-01-01

157

Coronal ion-cyclotron beam instabilities within the multi-fluid description  

E-print Network

Spectroscopic observations and theoretical models suggest resonant wave-particle interactions, involving high-frequency ion-cyclotron waves, as the principal mechanism for heating and accelerating ions in the open coronal holes. However, the mechanism responsible for the generation of the ion-cyclotron waves remains unclear. One possible scenario is that ion beams originating from small-scale reconnection events can drive micro-instabilities that constitute a possible source for the excitation of ion-cyclotron waves. In order to study ion beam-driven electromagnetic instabilities, the multi-fluid model in the low-beta coronal plasma is used. While neglecting the electron inertia this model allows one to take into account ion-cyclotron wave effects that are absent from the one-fluid MHD model. Realistic models of density and temperature as well as a 2-D analytical magnetic field model are used to define the background plasma in the open-field funnel region of a polar coronal hole. Considering the WKB approximation, a Fourier plane-wave linear mode analysis is employed in order to derive the dispersion relation. Ray-tracing theory is used to compute the ray path of the unstable wave as well as the evolution of the growth rate of the wave while propagating in the coronal funnel. We demonstrate that, in typical coronal holes conditions and assuming realistic values of the beam velocity, the free energy provided by the ion beam propagating parallel the ambient field can drive micro-instabilities through resonant ion-cyclotron excitation.

R. Mecheri; E. Marsch

2007-06-06

158

A KINETIC MODEL OF SOLAR WIND GENERATION BY OBLIQUE ION-CYCLOTRON WAVES  

SciTech Connect

The fast solar wind is generated by extended perpendicular ion heating in coronal holes, but the kinetic mechanism responsible for this heating has not been determined. One long-standing possibility is the resonant-cyclotron dissipation of ion-cyclotron waves, replenished from a turbulent cascade of interacting counter-propagating Alfven waves. We present results of a kinetic model for proton heating by the quasilinear resonant-cyclotron wave-particle interaction in a coronal hole. The resonant wave spectrum is taken as a power law in wavenumber, uniformly distributed in propagation direction between 0 deg. and 60 deg. with respect to the large-scale radial magnetic field. We obtain the steady-state solution of the kinetic guiding-center equation for the proton distribution in an expanding coronal hole, including the effects of large-scale forces of gravity, charge-separation electric field, Alfven wave ponderomotive force, and mirror force, along with the small-scale scattering from the wave dissipation. We find that plausible wave intensities can yield reasonable flow speeds and temperatures in the heliocentric radial range between 2 and 6 solar radii. We address the claim in earlier work that dissipation of parallel-propagating ion-cyclotron waves cannot provide enough acceleration and show that claim to be incorrect. We find that the combined action of the large-scale forces and the resonant-cyclotron scattering produces proton distribution functions with a characteristic structure: compressed in the sunward half of velocity space with a high-density shell separate from the origin, and relatively expanded in the anti-sunward half of velocity space. We suggest that qualitatively similar proton distributions would result from the kinetic evolution of any sufficiently effective perpendicular heating mechanism operating in an expanding coronal hole.

Isenberg, Philip A.; Vasquez, Bernard J. [Institute for the Study of Earth, Oceans and Space and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States)

2011-04-20

159

Whistler and Alfvén Mode Cyclotron Masers in Space  

NASA Astrophysics Data System (ADS)

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.

Trakhtengerts, V. Y.; Rycroft, M. J.

2012-10-01

160

Whistler and Alfvén Mode Cyclotron Masers in Space  

NASA Astrophysics Data System (ADS)

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.

Trakhtengerts, V. Y.; Rycroft, M. J.

2008-11-01

161

Acceleration of suprathermal ions by lightning-generated ion cyclotron waves.  

NASA Astrophysics Data System (ADS)

Lightning-induced emissions play important role in ion dynamics in the low-altitude magnetosphere. In particular, resonant interaction of ions with lower hybrid waves excited by lightning discharges leads to efficient ion heating; and the interaction with ion cyclotron waves is considered as a preheating mechanism. Such resonant wave-particle interaction is usually considered in two limiting cases: in the framework of quasi-linear theory, when the interaction with small amplitude wide spectrum waves is assumed, and in the case of monochromatic waves. In this report, we discuss resonant interaction of ions with special ion cyclotron wave packets which do not correspond to any of these cases. Some of wave packets formed of ion cyclotron waves generated by lightning strokes have a peculiar type of trajectories: they get stuck in the region where wave frequency becomes close to the local ion cyclotron frequency. These wave packets are characterized by wave frequency and wave vector which vary in space and time and, thus, along particle trajectory. What is more, the wave vector increases linearly with time. We derive the equations describing resonant interaction of ions with such ion cyclotron wave packets and obtain the resonance conditions. For suprathermal ions under consideration, the first cyclotron resonance gives the main contribution to resonant interaction. We show that the resonance condition for this resonance is defined by the detuning of the wave frequency from the local ion cyclotron frequency. The equations of motion have been solved numerically for test particles. Numerical results and analytical estimates demonstrate the essential difference between the interaction under consideration and the case of wide spectrum waves described by quasi-linear theory. Whereas the latter leads to particle diffusion in the phase space, the interaction we study leads to preferential ion acceleration. Hence, the ion energization has a non-diffusive character. The results obtained provide strong evidence that the acceleration of ions due to resonant interaction with these wave packets can be efficient for realistic wave field amplitudes. In addition, such non-diffusive ion energization leads to the corresponding wave damping.

Kuzichev, Ilya; Shklyar, David

162

Cyclotron dynamics of interacting bosons in artificial magnetic fields  

NASA Astrophysics Data System (ADS)

We study theoretically quantum dynamics of interacting bosons in artificial magnetic fields as engineered in recent ultracold atomic experiments, where quantum cyclotron orbital motion has been observed. With exact numerical simulations and perturbative analyses, we find that interactions induce damping in the cyclotron motion. The damping time is found to be dependent on interaction and tunneling strengths monotonically, while its dependence on magnetic flux is nonmonotonic. Sufficiently strong interactions would render bosons dynamically localized, inhibiting the cyclotron motion. The damping predicted by us can be construed as an interaction-induced quantum decoherence of the cyclotron motion.

Li, Xiaopeng; Das Sarma, S.

2014-06-01

163

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

NASA Astrophysics Data System (ADS)

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.

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

164

Medical Practice Makes Perfect  

NASA Technical Reports Server (NTRS)

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.

1998-01-01

165

Bio-Nano ECRIS: An electron cyclotron resonance ion source for new materials productiona)  

NASA Astrophysics Data System (ADS)

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 C60 ion beam production.

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

2010-02-01

166

Backward branch of surface dust cyclotron wave in a semi-bounded magnetized dusty plasma  

SciTech Connect

The surface dust cyclotron waves are investigated in semi-bounded magnetized dusty plasmas. The dispersion relation is obtained by the plasma dielectric function with the specular reflection boundary condition. The result shows the existence of the low-frequency backward wave branch in the surface dust cyclotron wave. The frequency of the wave is found to be decreased with the dust Debye wave number. It is also found that there is a minimum position of the scaled group velocity in the small-wave-number region. It is interesting to note that the group velocity increases below the minimum position and, however, decreases above the minimum position with increasing the dust Debye wave number.

Chang, Won-Seok; Chang, Dong-Man; Jung, Iyoung Michelle; Jung, Young-Dae [Department of Applied Physics, Hanyang University, Ansan, Kyunggi-Do 426-791 (Korea, Republic of); Hanyoung Foreign Language High School, Seoul 134-837 (Korea, Republic of); Department of Applied Physics and Institute of Natural Science and Technology, Hanyang University, Ansan, Kyunggi-Do 426-791 (Korea, Republic of)

2006-01-15

167

Quality inspection of small diameter polymeric medical tubing and attached wire stent using TAP-NDE and the Gabor Wavelet Transform  

E-print Network

medical tubing. Laser generated interrogating ultrasonic waves in the tubing were detected by use of a Fiber-Tip Interferometer (FTI) and a continuous wave HeNe laser. The time-frequency analysis of the generated dispersive waves was performed using...

Harms, Kent David

2001-01-01

168

Cyclotron Maser Radiation from an Inhomogeneous Plasma  

SciTech Connect

Cyclotron maser radiation is important in both laboratory devices such as gyrotrons and in space physics applications to phenomena such as auroral kilometric radiation. To understand the behavior, especially in the latter case where there is generally a localized region of instability, requires an understanding of how such instabilities behave in an inhomogeneous plasma. Here we consider, for simplicity, a simple ring distribution of electrons in either a step function variation of magnetic field or a continuous gradient. In each case we show that there can exist localized regions of instability from which waves, growing in time, can be radiated outwards.

Cairns, R. A.; Vorgul, I. [University of St Andrews, School of Mathematics and Statistics, St Andrews, Fife, Scotland, KY16 9SS (United Kingdom); Bingham, R. [STFC Rutherford Appleton Lab, Space Science and Technology Dept, Didcot, Oxon, OX11 0QX (United Kingdom); Physics Department, University of Strathclyde, Glasgow, G4 0NG (United Kingdom)

2008-11-21

169

Electron cyclotron heating in TMX-Upgrade  

SciTech Connect

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.

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

1981-01-01

170

Ion cyclotron harmonics in the Saturn downward current auroral region  

E-print Network

Ion cyclotron harmonics in the Saturn downward current auroral region J. D. Menietti,1 P. Schippers electron beams and diffuse ion beams have been reported during a pass by Cassini in a downward current Investigation (CAPS) instrument we have been able to identify ion cyclotron harmonic waves associated

Santolik, Ondrej

171

PLC Application in the Control of CIAE-30 Cyclotron  

E-print Network

Application of Programmable Logic Controller ( PLC ) brings CIAE-30 compact cyclotron into entirely automatic control, from cyclotron start-up until required beam current obtained at target can be performed with a single function key. The main parameters are sequentially set-up and regulated by PLC requiring no operators during routine production. High anti-interference ability, reliable safety interlocks, real time status monitoring and interchangeable operation modes of either full or half-full control, makes cyclotron reliable, stable, flexible and can display the dynamic status all the time. Processes of radioisotope production, e.g. targetry, chemical analyses, radioactivity monitoring and protection can be also performed with the same PLC. The cyclotron has been commissioned over the last two years and proved that the hardware arrangement and software structure of the whole control system are practical and successful. 1 Relation between PLC and cyclotron CIAE-30 compact cyclot...

Li Zhenguo China

172

Cyclotron resonance effects on stochastic acceleration of light ionospheric ions  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

173

Abortion - medical  

MedlinePLUS

Therapeutic medical abortion; Elective medical abortion; Induced abortion; Nonsurgical abortion ... A medical, or nonsurgical, abortion can be done within 7 weeks from the first day of the woman's last ...

174

Medication Errors  

MedlinePLUS

... for Healthcare Research and Quality: Medical Errors and Patient Safety Centers for Disease Control and Prevention: Medication Safety Department of Veterans Affairs National Center for Patient Safety Institute for Safe Medication Practices To Err is ...

175

Probing strong magnetic fields with cyclotron lines  

NASA Astrophysics Data System (ADS)

The physics of accretion of X-ray pulsars are dominated by very strong magnetic fields of of the order of 1012 Gauss. The only direct measure of these magnetic fields is the spectral analysis of cyclotron resonance scattering features (CRSFs). Electron CRSFs can form as broad harmonic absorption features in the keV regime when X- ray photons resonantly scatter with quantized electrons in the strongly magnetized accretion plasma. Recently, also the detection of proton CRSFs for magnetars has been claimed, rendering the basic understanding of the formation of CRSFs an important factor also for another class of fascinating extreme objects. In both cases, the line positions are directly linked to the magnetic field strength of the neutron star. Using Monte Carlo simulations, we perform a detailed study of the line shapes and positions of electron cyclotron lines of accreting neutron stars. These are indicators not only of the magnetic field strength but also give insight into the geometry of accretion, the structure of the magnetic field and gravitational effects around the compact object. For the first time ever, we have build a simulation based XSPEC model application to quantitatively compare our theoretical results to real observed source data. Recent results and their meaning for the physical picture of accreting X-ray pulsars from a comparison of the Monte Carlo Model to a set of sources are presented.

Schönherr, Gabriele; Wilms, Jörn; Kretschmar, Peter; Kreykenbohm, Ingo; Pottschmidt, Katja; Suchy, Slawo; Rothschild, Rick; Caballero, Isabel

176

Ion cyclotron bands in VLF saucers  

NASA Technical Reports Server (NTRS)

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.

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

1990-01-01

177

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

SciTech Connect

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.

Som, Sumit; Ghosh, Surajit; Seth, Sudeshna; Mandal, Aditya; Paul, Saikat; Roy, Suprakash [Variable Energy Cyclotron Centre, Kolkata (India)] [Variable Energy Cyclotron Centre, Kolkata (India)

2013-11-15

178

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

NASA Astrophysics Data System (ADS)

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 ? 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.

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

179

Electromagnetic ion cyclotron waves observed near the oxygen cyclotron frequency by ISEE 1 and 2  

NASA Technical Reports Server (NTRS)

The first results of observations of ion cyclotron waves by the elliptically orbiting ISEE 1 and 2 pair of spacecraft are reported. The most intense waves (8 nT) were observed in the outer plasmasphere where convection drift velocities were largest and the Alfven velocity was a minimum. Wave polarization is predominantly left-handed with propagation almost parallel to the ambient magnetic field, and the spectral slot and polarization reversal predicted by cold plasma propagation theory are identified in the wave data. Computations of the experimental wave spectra during the passage through the plasmapause show that the spectral slots relate to the local plasma parameters, possibly suggesting an ion cyclotron wave growth source near the spacecraft. A regular wave packet structure seen over the first 30 min of the event is attributed to the modulation of this energy source by the Pc 5 waves seen at the same time.

Fraser, B. J.; Samson, J. C.; Hu, Y. D.; Mcpherron, R. L.; Russell, C. T.

1992-01-01

180

Electron cyclotron resonance charge breeder (invited)  

NASA Astrophysics Data System (ADS)

Initially developed for radioactive ion beam production, the electron cyclotron resource (ECR) charge breeder shows that the beam injection of a primary beam inside an ECR ion source is a very general process for beam production. In this article we will review the latest results obtained on the ISN Grenoble test bench for the production of clockwise (CW) or pulsed metallic ion beams with the so-called "1+/n+" method. New results are given for CW operation where the efficiency is particularly optimized for application to multicharged radioactive ion production (for example, 3.5% for Zn1+?Zn9+, 4.2% for Pb1+?Pb24+, 5% for Rb1+?Rb15+). Different ion sources have been used to study the variation of the efficiency as a function of the energy of the 1+ primary beam. Charge state distributions are especially measured for Pb and Rb ions. A new mode of operation, the electron cyclotron resonance ion trap breeder/buncher, which permits the trapping and the bunching of the n+ ion beam is demonstrated and experimentally verified. The injection of a 400 nAeRb1+ ion beam leads to a 11.5 ?Ae peak current of the Rb15+ ion beam extracted during the first ms. The temporal evolution of the cumulated particle transformation and trapping efficiency is measured in the case of Rb15+. This new method shows that it is possible to modify the time structure of the injected beam, just by trapping the ions inside the plasma and re-extracting them by using the "afterglow pulsed mode." It will also be shown that it is possible to produce "multi-charged metallic ions" by using a primary source for the dissociation of a complex molecule and then by injecting the low charge state beam inside the multicharged electron cyclotron resonance ion source. A preliminary example will be presented for the production of U26+ by injection of U3+ obtained from dissociation of UF6 gas.

Sortais, P.; Bruandet, J. F.; Bouly, J. L.; Chauvin, N.; Curdy, J. C.; Geller, R.; Lamy, T.; Sole, P.; Vieux-Rochaz, J. L.

2000-02-01

181

HISTORY of the UMH Medical Library The medical library of Cedars Medical Center was initially housed in a remove and relatively  

E-print Network

HISTORY of the UMH Medical Library 1 The medical library of Cedars Medical Center was initially subscriptions were purchased through dues of the Medical Staff. Selections of material were based and Journals for the Small Medical Library. Requests from medical staff members were incorporated

Miami, University of

182

Experimental Observation of Ion-Cyclotron Turbulence in the Presence of Transverse-Velocity Shear.  

NASA Astrophysics Data System (ADS)

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~ 10^9 cm^{-3}, rho_{i} ~ 0.2 cm, T_{e} = T_{i} ~ 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 ~ 1.2Omega_{rm 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 vec{E} times vec{B} direction with k_thetarho_{i} = 0.4 and m = 1. The frequency spectrum becomes broadband and spiky, and shifts with the applied TLE strength. In contrast to CDEIC waves, the IEDD wave spectrum can extend to frequencies below Omega_{ rm i}. The waves have peak oscillation amplitude located off-axis in the region of maximum TLE.

Amatucci, William E.

183

Medical Matrix  

NSDL National Science Digital Library

Medical Matrix is a Web resource that offers a database of Internet clinical medicine resources. Medical Matrix categorizes resources by disease, specialty, and other interest areas. It is designed as a "home page" for a physician's or healthworker's computer. Medical Matrix is a project of the Internet Working Group of the American Medical Informatics Association.

184

MEDICAL "DEPRIVATION."  

ERIC Educational Resources Information Center

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

SUCHMAN, EDWARD A.

185

Cyclotron maser radiation from inhomogeneous plasmas  

SciTech Connect

Cyclotron maser instabilities are important in space, astrophysical, and laboratory plasmas. While extensive work has been done on these instabilities, most of it deals with homogeneous plasmas with uniform magnetic fields while in practice, of course, the systems are generally inhomogeneous. Here we expand on our previous work [R. A. Cairns, I. Vorgul, and R. Bingham, Phys. Rev. Lett. 101, 215003 (2008)] in which we showed that localized regions of instability can exist in an inhomogeneous plasma and that the way in which waves propagate away from this region is not necessarily obvious from the homogeneous plasma dispersion relation. While we consider only a simple ring distribution in velocity space, because of its tractability, the ideas may point toward understanding the behavior in the presence of more realistic distributions. The main object of the present work is to move away from consideration of the local dispersion relation and show how global growing eigenmodes can be constructed.

Cairns, R. A.; Vorgul, I. [School of Mathematics and Statistics, University of St. Andrews, St. Andrews, Fife KY16 9SS (United Kingdom); Bingham, R. [STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom); Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Ronald, K.; Speirs, D. C.; McConville, S. L.; Gillespie, K. M.; Bryson, R.; Phelps, A. D. R.; Cross, A. W.; Roberston, C. W.; Whyte, C. G.; He, W. [Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Kellett, B. J. [STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX (United Kingdom)

2011-02-15

186

Cyclotron side band emissions from magnetospheric electrons  

NASA Technical Reports Server (NTRS)

Very low frequency emissions with subharmonic cyclotron frequency from magnetospheric electrons were detected by the S(3)-A satellite (Explorer 45) whose orbit is close to the magnetic equatorial plane where the wave-particle interaction is most efficient. These emissions were observed during the main phase of a geomagnetic storm in the nightside of the magnetosphere outside of the plasmasphere. During the event of these side-band emissions, the pitch angle distributions of high energy electrons (greater than 50 keV) and of energetic protons (greater than 100 keV) showed remarkable changes with time, whereas those of low energy electrons and protons remained approximately isotropic. In this type of event, emissions consist essentially of two bands, the one below the equatorial electron gyrofrequency, and the other above. The emissions below are whistler mode, and the emissions above are electrostatic mode.

Maeda, K.

1975-01-01

187

Beam cyclotron instability in a dusty plasma  

NASA Astrophysics Data System (ADS)

A beam cyclotron instability in a plasma composed of magnetized ions and electrons and unmagnetized, negatively charged dust is investigated using linear kinetic theory. We consider the case where an ion E × E drift leads to the excitation of a discrete wavenumber spectrum of waves with frequency on the order of the dust plasma frequency for propagation perpendicular to the magnetic field. The unstable wavelengths are short, on the order of the ion gyroradius. Collisions of charged particles with neutrals are taken into account, as well as ion-dust and dust-dust collisions, which can be significant at the lower pressures considered. The behavior of the instability for oblique propagation is also considered. Application to possible laboratory dusty magnetoplasma parameters is discussed.

Rosenberg, M.

2014-08-01

188

Cyclotron maser radiation from inhomogeneous plasmas  

NASA Astrophysics Data System (ADS)

Cyclotron maser instabilities are important in space, astrophysical, and laboratory plasmas. While extensive work has been done on these instabilities, most of it deals with homogeneous plasmas with uniform magnetic fields while in practice, of course, the systems are generally inhomogeneous. Here we expand on our previous work [R. A. Cairns, I. Vorgul, and R. Bingham, Phys. Rev. Lett. 101, 215003 (2008)] in which we showed that localized regions of instability can exist in an inhomogeneous plasma and that the way in which waves propagate away from this region is not necessarily obvious from the homogeneous plasma dispersion relation. While we consider only a simple ring distribution in velocity space, because of its tractability, the ideas may point toward understanding the behavior in the presence of more realistic distributions. The main object of the present work is to move away from consideration of the local dispersion relation and show how global growing eigenmodes can be constructed.

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

2011-02-01

189

Improving cancer treatment with cyclotron produced radionuclides. Progress report  

SciTech Connect

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.

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

1993-11-01

190

The NSCL cyclotron gas stopper - Under construction  

NASA Astrophysics Data System (ADS)

Rare isotopes are produced at the NSCL by projectile fragmentation at energies on the order of 100 MeV/u for a wide range of research. In order to provide these exotic ions to low-energy high precision experiments such as the Penning-trap mass spectrometer LEBIT and the collinear laser spectroscopy setup, or to the NSCL's re-accelerator (ReA), the beam must be slowed down into the eV range by solid degraders and interaction with buffer gas. A novel gas-filled reverse cyclotron is currently under construction by the NSCL and will complement a recently installed linear gas-filled cell. The new device is based on a 2.6 T maximum-field cyclotron-type three-sectored magnet to confine the injected beam while it is slowed down in ?100 mbar of high-purity helium gas, cooled to liquid-nitrogen temperature. Once thermalized, the beam is transported to the center of the device by a novel RF-carpet system, extracted along the symmetry axis and accelerated to a few tens of keV of energy for delivery to the users. The device has been characterized in numerous simulations with full 3D models of its magnetic field. The beam transport has been modeled from the fragment separator to the point where they reach thermal energies. The simulations indicate that very efficient stopping and fast extraction will be possible even for light and medium-mass ions, which are difficult to efficiently thermalize in linear gas cells. Construction of the device is well underway and initial tests are planned for later this year. The design and the predicted performance of the machine is discussed and its construction status is given.

Schwarz, S.; Bollen, G.; Brodeur, M.; Chouhan, S. S.; DeKamp, J.; Gehring, A. E.; Joshi, N. S.; Magsig, C.; Morrissey, D. J.; Ringle, R.; Ottarson, J.; Zeller, A. F.

2013-12-01

191

Global Simulation of Electromagnetic Ion Cyclotron Waves  

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

192

Global Simulation of Electromagnetic Ion Cyclotron Waves  

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

193

106-GHz electron cyclotron heating system for heliotron-E  

SciTech Connect

A new high-power electron cyclotron heating system has been installed for the Heliotron-E helical device. This system is designed to operate at 106-GHz frequency with a half-megawatt output power. The system consists of a pulse gyrotron with TE[sub 12,2] whispering gallery mode (WGM) output, conversion system of the WGM into the Gaussian-like beam, transmission line for HE[sub 11] mode, and launching system. From measurement of radiation patterns, it was confirmed that the WGM was effectively converted into the Gaussian-like beam, and the emergent radiation profile from the tubular oversized corrugated waveguide was close to a circular Gaussian one even when the beam coupled to the HE[sub 11] mode had the side lobes before the transmission. This indicates that the oversized corrugated waveguides act as a mode filter. The launching system effectively focuses the Gaussian beam in the free space to a 2-cm (poloidal) [times] 3-cm (toroidal) e-folding power spot size. These are small enough compared with the plasma minor radius ([approximately]15 cm). It is expected that the power deposition can be well localized in the plasma central region. 21 refs., 10 figs.

Nagasaki, Kazunobu; Iima, Masashi; Kobayashi, Sakuji; Sakamoto, Kinzo; Zushi, Hideki (Kyoto Univ. Plasma Physics Laboratory (Japan)); Sato, Motoyasu (National Institute for Fusion Science, Nagoya (Japan))

1994-07-01

194

Ion cyclotron transmission spectroscopy in the Tokamak Fusion Test Reactor  

SciTech Connect

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.

Greene, G.J.

1993-09-01

195

Design Study Of Cyclotron Magnet With Permanent Magnet  

NASA Astrophysics Data System (ADS)

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.

Kim, Hyun Wook; Chai, Jong Seo

2011-06-01

196

Multiple frequency electron cyclotron heating for the Levitated Dipole Experiment  

E-print Network

The use of multiple frequencies of electron cyclotron resonance heating (ECRH) in the Levitated Dipole Experiment (LDX) is an important tool that will tailor the plasma profiles. Initial LDX plasmas have been created using ...

Mahar, Scott B

2005-01-01

197

Design Study Of Cyclotron Magnet With Permanent Magnet  

SciTech Connect

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.

Kim, Hyun Wook [Lab. Of Accelerator and Medical Engineering, SungKyunKwan University, Cheoncheon-dong, Jangan-gu, Suwon Gyeonggi-do 440-746 (Korea, Republic of); Chai, Jong Seo [Lab. Of Accelerator and Medical Engineering, SungKyunKwan University, Cheoncheon-dong, Jangan-gu, Suwon Gyeonggi-do 440-746 (Korea, Republic of); Department of Energy Science, SungKyunKwan University, Cheoncheon-dong, Jangan-gu, Suwon Gyeonggi-do 440-746 (Korea, Republic of)

2011-06-01

198

Magnetosphere cyclotron maser: Backward wave oscillator generation regime  

Microsoft Academic Search

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

V. Y. Trakhtengerts

1995-01-01

199

LE JOURNAL DE PHYSIQUE DISPOSITIF DE SYNCHRONISATION AUTOMATIQUE DU CYCLOTRON  

E-print Network

LE JOURNAL DE PHYSIQUE ET LE RADIUM DISPOSITIF DE SYNCHRONISATION AUTOMATIQUE DU CYCLOTRON Par réalisation d'un dispositif de synchronisation du cyclotron, permettant de faire fonctionner cet appareil avec » entre la valeur du champ magnétiqu.e et celle de la fréquence de la tension accélératrice appliquée

Boyer, Edmond

200

Far infrared spectroscopy with high resolution cyclotron resonance filters  

Microsoft Academic Search

A new type of far infrared spectroscopy based on a cyclotron resonance notch filter is demonstrated. The resonant absorption energy of such a filter is tuned by an external magnetic field. GaAs\\/AlGaAs heterostructures with high mobility two-dimensional electron gas are used to obtain an optimal cyclotron resonance filter. With such a filter, we can analyze far infrared radiation in the

C. Skierbiszewski; W. Knap; D. Dur; E. L. Ivchenko; S. Huant; B. Etienne

1998-01-01

201

Cyclotron Resonance Vanishing effect in Correlated 2D Electron Systems  

Microsoft Academic Search

``Cyclotron Resonance - Vanishing effect'' (CRV) arise on magnetospectra of cyclotron resonance line (CR) as a well-defined gap that reduce to zero CR effect. CRV have been discovered due to experimental study of terahertz radiation transmission and photoresistivity magnetospectra at CR conditions in two-dimensional electron system (2DES) of GaAs\\/AlGaAs nanostructures with higher electron mobility at low (non-quantized Hall effect) magnetic

Andre Chebotarev; Galina Chebotareva

2009-01-01

202

A CW RFQ injector for the IUCF cyclotron  

Microsoft Academic Search

Work has begun to upgrade the IUCF 210 MeV proton cyclotrons for use as a dedicated proton source for cancer treatment and other applications requiring medium energy dc proton beams. A major performance and reliability upgrade to replace the 600 kV Cockcroft Walton with a 700 keV proton CW RFQ as the pre-accelerator for the 15 MeV injector cyclotron is

D. L. Friesel; V. Anferov; R. W. Hamm

2001-01-01

203

Superconducting magnet for K-500 cyclotron at VECC, Kolkata  

Microsoft Academic Search

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 4.2K by interfacing with LHe plant and energized to its rated current on 30th April, 2005 producing magnetic field of 4.8T at median plane of

Subimal Saha; Jayanta Choudhury; Gautam Pal; D. P. Hajra; R. Dey; Amitava Sur; R. K. Bhandari

2009-01-01

204

Mirror and ion cyclotron anisotropy instabilities in the magnetosheath  

NASA Technical Reports Server (NTRS)

The kinetic properties of the ion cyclotron anisotropy and the mirror instabilities are investigated using one-dimensional hybrid simulations. It is found that, for moderate values of the ion beta and the proton temperature anisotropy, the two instabilities produce similar levels of turbulence. For high values of beta or temperature anisotropy, the ion cyclotron instability produces higher fluctuation levels of turbulence than does the mirror instability.

Mckean, M. E.; Winske, D.; Gary, S. P.

1992-01-01

205

Cyclotrons 2007 March 31, 2008 Three-Ring FFAG Complex  

E-print Network

Cyclotrons 2007 March 31, 2008 Three-Ring FFAG Complex for H+ and C6+ Therapy E. Keil, A.M. Sessler[m] Carbon (69-400 MeV/n) Proton 31 & Carbon 69 MeV/n Proton (3.49-31 MeV) E. Keil page 3 #12;Cyclotrons 2007 March 31, 2008 Design Principles and H+ Beam Parameters · Accelerate H+ and C6+ ions in 3 non

Keil, Eberhard

206

Ion cyclotron resonance spectroscopy. Cyclotron double resonance provides a new technique for the study of ion-molecule reaction mechanisms.  

PubMed

Ion cyclotron resonance spectroscopy yields information on many aspects of ion-molecule chemistry. The method is ideally suited for experiments involving ion energies below several electron volts, and hence provides a valuable complement to other techniques (27). eyclotron double resonance is uniquely suitable for establishing relationships between reactant ions and their product ions in complex ion-molecule reaction sequences. The double-resonance experiments with isotopic species yield information on reaction mechanisms and the nature of intermediate species. Ion-molecule reactions which occur at low energies are quite sensitive to the nature of functional groups and the details of molecular structure (28). Reactions of ions or neutral molecules with specific reagents in the cyclotron spectrometer can thus be used to characterize unknown species. Once the systematic ion-molecule chemistry of useful reagents has been worked out, it should be possible to proceed in a manner directly analogous to classical chemical methods. Suppose, for example, that reagents A(+), B(+), C(+), and D(+) each have characteristic reactions with different functional groups. Then these reagents can all be mixed with an unknown neutral species, X, and each of the reactions, X + A(+) --> ?, X + B(+) --> ?, . . . . can be examined. In contrast to solution chemistry, all the reagents can be added simultaneously to the unknown, since each of the specific reactions can be examined by cyclotron double resonance. The reactions which occur, the species synthesized , and the products of degradation then characterize X. The same methodology can be applied to characterize an unknown ionic epecies X(+), through use of neutral reagents A, B, C, and D. For example, proton transfer reactions to neuteal species have been applied in studying ions of mass 45 produced from various sources (29). The order of the proton affinities of the neutral reagent molecules are as follows: NH(3) isobutylene propene. Ions of mass 45 can be produced by the protonation of ethylene oxide (see structure III), the protonation of acetaldehyde (see structure IV), and the fragmentation of dimethyl ether (see structure V). Those ions might be expected to have, respectively, the three structures: Proton transfer from the mass-45 ions from sources III and IV to NH(3) and to isobutylene occurs readily, but not proton transfer to propene. For the ion from source V, proton transfer to NH3 occurs, but not proton transfer to isobutylene or propene. Thus the proton transfer reactions to various neutral reagents demonstrate that the mass-45 ions from the various sources are different. This example is only a rudimentary version of an approach to the characterization of unusual ionic species; niore sophisticated applications can follow when the systematic chemistry of more reagents is available. This approach should be ideal for comparing nonclassical carbonium ions produced by different routes. Some very interesting ionic species are produced by rearrangements in the fragmentation of molecules, following electron impact. Such molecular rearrangements frequently result in the fragmentation of an ion radical to another ion radical with the elimination of a small neutral species (30). It should be possible to run these reactions in reverse to check the postulated mechanisms. An interesting result of the systematic study of proton transfer to various functional groups is the finding that the proton affinity of various amines and pyridine is extremely high (31). Species such as VI and VII: might be expected to be very stable; they are in fact so stable that they are unreactive with respect to subsequent chemistry at the charge center. Thus, if there are other functional groups on the ion, the important reactions should occur at these functional groups. It should be possible to design species for which the presence of the charge has little influence on the reactivity of a neutral functional group. In this case the charge functions simply as an inert label which makes the study of neutral-neutral

Baldeschwieler, J D

1968-01-19

207

Impact of a medical waste incinerator on mercury levels in lagoon fish from a small tropical island in the Western Pacific.  

PubMed

In 2004-2005, several species of marine fish were collected for mercury (Hg) analysis from Saipan Lagoon, Saipan, Commonwealth of the Northern Mariana Islands. Relatively high concentrations were found in representatives from the Hafa Adai Beach area located some distance from known sources of Hg contamination. A follow-up investigation aimed at identifying additional land-based sources of Hg in the area was launched in early 2007. The study identified a medical waste incinerator as the primary source of Hg enrichment. The incinerator was operational for about 20 years before it was closed down by the U.S. Environmental Protection Agency (EPA) in January 2006, for multiple violations of the Clean Air Act. Stormwater runoff from this facility entered a drainage network that discharged into the ocean at the southern end of Hafa Adai Beach, about 1 km away. At the time of this investigation storm drain sediments at the coast were only marginally enriched with mercury although values some 50x above background were detected in drainage deposits a few meters down-gradient of the incinerator site. Mercury concentrations in fish from the Hafa Adai Beach area were also significantly lower than those determined in similar species 3 yr earlier. The implications of the data are briefly discussed. PMID:21598167

Denton, Gary R W; Trianni, Michael S; Bearden, Brian G; Houk, Peter C; Starmer, John A

2011-01-01

208

Distribution of thermal neutron flux around a PET cyclotron.  

PubMed

The number of positron emission tomography (PET) examinations has greatly increased world-wide. Since positron emission nuclides for the PET examinations have short half-lives, they are mainly produced using on-site cyclotrons. During the production of the nuclides, significant quantities of neutrons are generated from the cyclotrons. Neutrons have potential to activate the materials around the cyclotrons and cause exposure to the staff. To investigate quantities and distribution of the thermal neutrons, thermal neutron fluxes were measured around a PET cyclotron in a laboratory associating with a hospital. The cyclotron accelerates protons up to 18 MeV, and the mean particle current is 20 ?A. The neutron fluxes were measured during both 18F production and C production. Gold foils and thermoluminescent dosimeter (TLD) badges were used to measure the neutron fluxes. The neutron fluxes in the target box averaged 9.3 × 10(6) cm(-2) s(-1) and 1.7 × 10(6) cm(-2) s(-1) during 18F and 11C production, respectively. Those in the cyclotron room averaged 4.1 × 10(5) cm(-2) s(-1) and 1.2 × 10(5) cm(-2) s(-1), respectively. Those outside the concrete wall shielding were estimated as being equal to or less than ?3 cm s, which corresponded to 0.1 ?Sv h(-1) in effective dose. The neutron fluxes outside the concrete shielding were confirmed to be quite low compared to the legal limit. PMID:21451309

Ogata, Yoshimune; Ishigure, Nobuhito; Mochizuki, Shingo; Ito, Kengo; Hatano, Kentaro; Abe, Junichiro; Miyahara, Hiroshi; Masumoto, Kazuyoshi; Nakamura, Hajime

2011-05-01

209

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

NASA Astrophysics Data System (ADS)

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.

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

2014-11-01

210

Oral Medication  

MedlinePLUS

... over-the-counter items. Explore: Oral Medication How Much Do Oral Medications Cost? Save money by finding the right type and ... Options? Is There a Danger of Interactions? How Much Do Oral Medications Cost? We Can Help (Long) - we-can-help-long. ...

211

Mean magnetic field calculation program with allowance for flutter for isochronous cyclotron (Cyclotron Analytic Model Program - CAMP)  

E-print Network

The Cyclotron Analytic Model Program (CAMP) written in C++ with the use of Visual C++ is described. The program is intended for the mean magnetic field calculation of the isochronous cyclotron with allowance for flutter. The program algorithm was developed on the basis of the paper 'Calculation of Isochronous Fields for Sector-Focused Cyclotrons', by M.M.Gordon (Particle Accelerators. 1983. V.13). The accuracy of the calculations, performed with this program, was tested with the use of maps of isochronous magnetic fields of different cyclotrons with the azimuthally varying fields - AVF cyclotrons, in which the ion beams were produced. The calculation by CAMP showed that the isochronous mean magnetic field curve for the measured magnetic field, in which the ion beam was produced, exactly corresponded to the curve of the isochronous mean magnetic field, calculated with the allowance for flutter for all the AVF cyclotrons that were considered. As is evident from the calculations, this program can be used for cal...

Kiyan, I N; Vorozhtsov, S B

2002-01-01

212

[Medical technology and medical education].  

PubMed

The education of medical professionals is divided into medical studies, postgraduate training leading to the qualification as a specialist, and continuing professional development. During education, all scientific knowledge and practical skills are to be acquired, which enable the physician to practice responsibly in a specialized medical area. In the present article, relevant curricula are analyzed regarding the consideration of medical device-related topics, as the clinical application of medical technology has reached a central position in modern patient care. Due to the enormous scientific and technical progress, this area has become as important as pharmacotherapy. Our evaluation shows that medical device-related topics are currently underrepresented in the course of medical education and training and should be given greater consideration in all areas of medical education. Possible solutions are presented. PMID:20700785

von Mallek, D; Biersack, H-J; Mull, R; Wilhelm, K; Heinz, B; Mellert, F

2010-08-01

213

30-cm electron cyclotron plasma generator  

NASA Technical Reports Server (NTRS)

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.

Goede, Hank

1987-01-01

214

Analytical representation of cyclotron magnetic field  

SciTech Connect

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.

Lee-Whiting, G.E.; Davies, W.G. [AECL Research, Chalk River, Ontario (Canada). Chalk River Labs.] [AECL Research, Chalk River, Ontario (Canada). Chalk River Labs.

1994-07-01

215

Cyclotron-based effects on plant gravitropism  

NASA Astrophysics Data System (ADS)

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 ?-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.

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

216

Ion Cyclotron Waves at Titan: Harbingers of Atmospheric Loss  

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

217

Influence of wall impedance and self-fields on the cyclotron maser instability  

SciTech Connect

The compound influence of wall impedance and self-fields on the cyclotron maser instability is investigated for a hollow electron beam. A stability analysis is carried out using the linearized Vlasov-Maxwell equations, under the assumption that the beam thickness is small compared to the beam radius. A dispersion relation is derived and solved numerically to study the effects of the wall impedance and self-fields on the cyclotron maser instability. These effects lead to the elliptical motion of the equilibrium configuration. The growth rate decreases due to the wall resistivity and self-fields. It has been shown that the interaction between the self-field and impedance effects is in the lower reduction in the growth rate when they are both present compared to their separate effects added together. The instability bandwidth increases due to the wall impedance and decreases due to the self fields. In the presence of self-fields, a very small increase in the wall impedance causes an increase in the instability bandwidth. This shows that the widening effect of the bandwidth due to the wall impedance is dominant and prevails over the narrowing effect of the self-field.

Khalilzadeh, Elnaz; Maraghechi, Behrouz [Department of Physics, Amirkabir University of Technology, P. O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Chakhmachi, Amir [Department of Physics, Amirkabir University of Technology, P. O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran, P.O. Box 14155-1339 (Iran, Islamic Republic of)

2009-09-01

218

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

PubMed

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

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

219

[Resources in medical research].  

PubMed

The biennial national statistical surveys of research and development expenditure, based on OECD guidelines, contribute to the knowledge base for Norwegian research policy. This article outlines the resources for research and development in the medical sciences, with emphasis on the higher education sector. This sector, which includes university hospitals, performs about 75% of medical research in Norway (medical research in industry not included) while the remaining 25% is performed in research institutes in the institute sector. In 1995, current expenditure for medical research amounted to 1,240 million Norwegian kroner, 930 million in the higher education sector and 310 million in the institute sector. From 1993 to 1995, there was a small increase in real terms in resources for medical research in universities and colleges paid for over institutional budgets, while there was no growth in externally funded research. Over the 25-year period 1970-1995, the growth in expenditures for medical research was higher than for the natural sciences, but lower than for the humanities and the social sciences. Comparisons between the Nordic countries show that investments in medical research in Norway is much lower than in Denmark or Sweden. PMID:9844517

Sundnes, S L

1998-10-30

220

Generation of Electromagnetic Bursts in the Plasma Cyclotron Maser  

NASA Astrophysics Data System (ADS)

We study experimentally the frequency and energy characteristics of electromagnetic waves in the plasma cyclotron maser, where the active medium is the two-component nonequilibrium plasma of an electron cyclotron resonance (ECR) discharge, which is produced by a high-power gyrotron radiation in a mirror trap. At the plasma decay stage, high-power (up to 200 W) pulses of electromagnetic radiation are detected synchronously with the precipitation of energetic electrons from the trap. This radiation propagates across the magnetic trap, and the radiation frequency fits in the interval between the electron gyrofrequency at the center of the mirror and the frequency of the electron cyclotron resonance heating. Synchronicity of the generated radiation with the electron precipitation out of the trap, as well as the dependence of the radiation frequency on the magnetic field of the trap, confirm the cyclotron mechanism of the arising instability. It is shown that electron precipitation, which is due to the cyclotron instability of the low-density plasma, ensures fast relaxation (as compared with the loss due to the Coulomb collisions) of the energy stored in the hot component of the plasma.

Viktorov, M. E.; Vodopyanov, A. V.; Golubev, S. V.; Izotov, I. V.; Mansfeld, D. A.

2013-06-01

221

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

NASA Astrophysics Data System (ADS)

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+ is 54 ?A. Many broken fullerenes such as C58 and C56 are observed in fullerene ion beams.

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

2008-11-01

222

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

SciTech Connect

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.

Tanaka, K. [Tateyama Machine Co., Ltd., 30 Shimonoban, Toyama, Toyama, 930-1305 (Japan); Bio-Nano Electronics Research centre, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-0815 (Japan); Muramatsu, M. [Bio-Nano Electronics Research centre, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-0815 (Japan); National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan); Uchida, T.; Hanajiri, T.; Yoshida, Y. [Bio-Nano Electronics Research centre, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-0815 (Japan); Biri, S. [Institute of Nuclear Research (ATOMKI), H-4026 Debrecen, Benter 18/c (Hungary); Asaji, T.; Shima, K. [Tateyama Machine Co., Ltd., 30 Shimonoban, Toyama, Toyama, 930-1305 (Japan); Kitagawa, A. [National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan); Kato, Y. [Division of Electrical Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

2008-11-03

223

Cyclotron-based of plant gravisensing  

NASA Astrophysics Data System (ADS)

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

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

224

Medical Assistants  

NSDL National Science Digital Library

For a concise summary of the medical assistant profession the Medical Assistants entry in the Bureau of Labor Statistics' Occupational Outlook Handbook is must read. The site covers topics ranging from the nature of the profession, working conditions, earnings, and more. The section on training, qualifications and advancement will be of special interest to medical assistant faculty and students. The section on sources of addition information will also be a good launching point for anyone seeking additional online resources.

2006-11-01

225

Nonlinear features of electrostatic ion cyclotron instability driven by counterstreaming ion beams in equatorial outer plasmasphere  

NASA Astrophysics Data System (ADS)

A commonly observed feature of the field-aligned flow of ions on closed geomagnetic field lines is that the pitch angle distributions are considerably broadened. Such pitch angle distributions facilitate in trapping ions and thus contribute to the process of plasmaspheric refilling. Since counterstreaming ion beams are a common feature of the early stage refilling as shown by models, we have investigated the role of ion-beam-driven instabilities in broadening the pitch angle distribution of the ion beams. The study is performed using a 2.5-dimensional particle-in-cell code. It is shown that for sufficiently fast ion beams as expected in the outer region of the plasmasphere, the ion cyclotron modes, which appear at frequencies less than the ion-cyclotron frequency ?i in the rest frame of the nondrifting electrons, are the dominant unstable wave modes. In the early stage of the instability a nearly purely growing mode dominates, which efficiently mediates in transferring a part of the parallel drift energy into the perpendicular energy, significantly broadening the ion pitch angle distribution. The transfer abruptly saturates when Jn(k??if)->0, where Jn( ) is the Bessel function of an appropriate order n, k? is the perpendicular wave number of the dominant mode, and ?if is the maximum value of the Larmor radius of the beam ions in anomalous cyclotron resonance with the wave. This behavior of the dominant mode in conjunction with the conservation of ion energy allows a method for including such wave-particle interaction effects in mesoscale models for the plasmaspheric refilling. The perpendicular acceleration of ions by this instability reduces the parallel drift only by a relatively small fraction, leaving the counterstreaming intact. However, the perpendicular acceleration produces a pitch angle distribution which is inducive for the trapping of the counterstreaming ions in the plasmaspheric flux tubes.

Singh, Nagendra; Leung, W. C.

226

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

PubMed

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. PMID:18315221

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

2008-02-01

227

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

SciTech Connect

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

Bhattacharjee, Tanushyam; Kanti Dey, Malay; Dhara, Partha; Roy, Suvodeep; Debnath, Jayanta; Balakrishna Bhole, Rajendra; Dutta, Atanu; Pradhan, Jedidiah; Pal, Sarbajit; Pal, Gautam; Roy, Amitava; Chakrabarti, Alok [Variable Energy Cyclotron Centre, 1/AF Bidhannagar, Kolkata 700064 (India)

2013-05-15

228

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

PubMed

In an isochronous cyclotron, measurements of central phase of the ion beam with respect to rf and the phase width provide a way to tune the cyclotron for maximum energy gain per turn and efficient extraction. We report here the development of a phase measurement system and the measurements carried out at the Variable Energy Cyclotron Centre's (VECC's) K = 500 superconducting cyclotron. The technique comprises detecting prompt ?-rays resulting from the interaction of cyclotron ion beam with an aluminium target mounted on a radial probe in coincidence with cyclotron rf. An assembly comprising a fast scintillator and a liquid light-guide inserted inside the cyclotron was used to detect the ?-rays and to transfer the light signal outside the cyclotron where a matching photo-multiplier tube was used for light to electrical signal conversion. The typical beam intensity for this measurement was a few times 10(11) pps. PMID:23742541

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

2013-05-01

229

Accelerator science in medical physics  

PubMed Central

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

Peach, K; Wilson, P; Jones, B

2011-01-01

230

Proton and helium cyclotron anisotropy instability thresholds in the magnetosheath  

NASA Astrophysics Data System (ADS)

Both the protons and the helium ions of the terrestrial magnetosheath typically display T (sub perpendicular) greater than T (sub parallel), where perpendicular to and parallel to denote directions perpendicular and parallel to the background magnetic field. Observations of the highly compressed magnetosheath show an inverse correlation between these ion temperature anisotropies and the parallel proton beta. Computer simulations have demonstrated that these correlations are due to wave-particle scattering by electromagnetic ion cyclotron anisotropy instabilities. These correlations correspond to linear theory thresholds of the proton cyclotron and the helium cyclotron instabilities. This paper uses linear Vlasov theory and the assumption of a constant maximum growth rate to obtain closed-form expressions for these thresholds as a function of the relative helium density and the parallel proton beta in a parameter model of the magnetosheath.

Gary, S. Peter; Convery, Patrick D.; Denton, Richard E.; Fuselier, Stephen A.; Anderson, Brian J.

1994-04-01

231

A laboratory study of collisional electrostatic ion cyclotron waves  

NASA Technical Reports Server (NTRS)

The effects of neutral-particle collisions on electrostatic ion cyclotron instability are analyzed. Experiments were conducted in the Q machine of Motley (1975) with a cesium plasma in which the neutral gas pressure in the main chamber varied from about 5 microtorr-10 mtorr. The relation between electrostatic ion cyclotron wave amplitude and frequency and neutral argon pressure is examined. It is observed that over the full range of neutral pressure the frequency changes by less than 10 percent and the ion cyclotron waves continue to be excited and reach amplitudes of at least several percent at values of the neutral pressure where the ion-neutral collision frequency/ion gyrofrequency is about 0.3.

Suszcynsky, D. M.; Cartier, S. L.; Merlino, R. L.; Dangelo, N.

1986-01-01

232

Radiation effects testing at the 88-inch cyclotron at LBNL  

SciTech Connect

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.

McMahan, Margaret A.; Koga, Rokotura

2001-10-09

233

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

SciTech Connect

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.

Zhang, P.; Domier, C. W.; Liang, T.; Kong, X.; Tobias, B.; Shen, Z.; Luhmann, N. C. Jr. [University of California at Davis, Davis, California 95616 (United States); Park, H. [Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Classen, I. G. J.; Pol, M. J. van de; Donne, A. J. H.; Jaspers, R. [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, 3430 BE Niewuwegein (Netherlands)

2008-10-15

234

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

PubMed

A 128 channel two-dimensional electron cyclotron emission imaging system collects time-resolved 16x8 images of T(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. PMID:19044590

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

2008-10-01

235

Production of fluorine-18 for medical applications  

E-print Network

of activity produced, in the purity and 18 possible chemical composition of the F and in the ease of production. This study has been limited to one of these reactions, using a-particles produced in a cyclotron. The method chosen produced less contamination... were used to contain the F, The 18 F produced was relatively free of contaminants and in a form convenient for medical applications. iv ACKNOWLEDGEMENTS Special and immeasurable thanks go to my advisor, Dr. Ron Macfarlane, for his endless patience...

Sullivan, Patricia Papa

2012-06-07

236

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

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

237

Temperature-resonant cyclotron spectra in confined geometries  

E-print Network

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.

Andrey Pototsky; Peter Hänggi; Fabio Marchesoni; Sergey Savel'ev

2011-05-22

238

A 600 MeV cyclotron for radioactive beam production  

SciTech Connect

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.

Clark, D.J.

1993-05-17

239

Theory of propagation of ordinary surface cyclotron waves  

SciTech Connect

The dispersion properties of ordinary surface cyclotron waves in a semiinfinite nonuniform plasma are investigated. The waves propagate across the external magnetic field directed along the plasma surface in a metal waveguide the internal surface of which is covered with a dielectric. The problem is solved analytically in the framework of a kinetic model for plasma particles under the assumption of weak spatial dispersion. The influence of the parameters of the dielectric layer separating the plasma from the metal wall, the shape of the plasma density profile, and the value of the external magnetic field on the dispersion properties of surface cyclotron waves is studied both numerically and analytically.

Girka, V. O.; Klyzhka, A. V. [Karazin Kharkiv National University (Ukraine)

2009-01-15

240

ELECTRON CYCLOTRON CURRENT DRIVE EFFICIENCY IN GENERAL TOKAMAK GEOMETRY  

SciTech Connect

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.

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

2003-03-01

241

Cyclotron resonance in II-VI semiconductors at THz region  

NASA Astrophysics Data System (ADS)

Cyclotron resonance experiments for various II-VI semiconductors (n-ZnO, n-ZnS, n-ZnSe, n-CdS, n-CdSe, n-CdTe) have been performed at ultra-high magnetic fields beyond 100 T. Cyclotron resonance and impurity related resonance are observed definitely with the use of THz radiation sources, and the magnetic field dependence of effective mass is obtained at a wide range of a THz region in n-type CdTe.

Imanaka, Y.; Takamasu, T.; Takehana, K.; Oshikiri, M.; Kido, G.; Nojiri, H.; Matsuda, Y. H.; Arimoto, H.; Takeyama, S.; Miura, N.; Karczewski, G.; Wojtowicz, T.; Kossut, J.

242

Two aspects of the K500 cyclotron project  

E-print Network

cyclotron magnet vas designed to produce magnetic fields that vill allow isochronous acceleration (see Appendix A) of ions vith a charge-to-mass ratio in the zange of 0. 01 to 0. 5 to final energies of betveen 0. 1 and 80 NeV/n (see Fig. 1) [7... (the first-harmonic term in the Fouzier expansion of the field) to better than e0. 5 gauss, the magnitude of the field must be measuzed to a precision of 1. 5 parts in 10 (7. 5 gauss at 50 kG) [9). 4 2. The K500 cyclotron main magnet The K500...

Van Baalen, Aaron Chase

2012-06-07

243

Numerical simulations of unbounded cyclotron-maser emissions  

NASA Astrophysics Data System (ADS)

Numerical simulations have been conducted to study the spatial growth rate and emission topology of the cyclotron-maser instability responsible for stellar/planetary auroral magnetospheric radio emission and intense non-thermal radio emission in other astrophysical contexts. These simulations were carried out in an unconstrained geometry, so that the conditions existing within the source region of some natural electron cyclotron masers could be more closely modelled. The results have significant bearing on the radiation propagation and coupling characteristics within the source region of such non-thermal radio emissions.

Speirs, David C.; McConville, S. L.; Gillespie, K. M.; Phelps, A. D. R.; Ronald, K.

2013-12-01

244

Backward Wave Cyclotron-Maser Emission in the Auroral Magnetosphere  

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

245

PROOF COPY 034509PHP Effectiveness of electron-cyclotron and transmission resonant heating  

E-print Network

resonant heating in inductively coupled plasmas Oleg V. Polomarov and Constantine E. Theodosiou University June 2005 The electron-cyclotron and transmission resonances in magnetically enhanced low-pressure one-cyclotron and transmission resonances, but normally does not exhibit a sharp peak at the electron-cyclotron resonance ECR

Kaganovich, Igor

246

Cyclotron resonance maser experiments in a bifilar helical waveguide Alon Aharony, Rami Drori, and Eli Jerby*  

E-print Network

Cyclotron resonance maser experiments in a bifilar helical waveguide Alon Aharony, Rami Drori 2000 Oscillator and amplifier cyclotron-resonance-maser CRM experiments in a spiral bifilar waveguide, 84.40.Ik, 84.40.Az I. INTRODUCTION Cyclotron resonance masers CRM's and related gyrode- vices

Jerby, Eli

247

Cyclotron-resonance maser in a periodically loaded quadrupole transmission line Y. Leibovitch and E. Jerby*  

E-print Network

Cyclotron-resonance maser in a periodically loaded quadrupole transmission line Y. Leibovitch and E; revised manuscript received 17 February 1999 A cyclotron-resonance maser CRM is implemented in a periodic, 84.40.Ik, 84.47. w I. INTRODUCTION Cyclotron-resonance masers CRMs and gyrotrons are known as high

Jerby, Eli

248

Cyclotron-resonance maser in a magnetic mirror Ronen Caspi and Eli Jerby*  

E-print Network

Cyclotron-resonance maser in a magnetic mirror Ronen Caspi and Eli Jerby* Faculty of Engineering, Tel Aviv University, Ramat Aviv 69978, Israel Received 4 February 1999 A cyclotron-resonance maser CRM 00808-9 PACS number s : 84.40.Ik I. INTRODUCTION Cyclotron-resonance masers CRM's 1 have been stud- ied

Jerby, Eli

249

Ferrite-guided cyclotron-resonance maser Eli Jerby,* A. Kesar, A. Aharony, and G. Breitmeier  

E-print Network

Ferrite-guided cyclotron-resonance maser Eli Jerby,* A. Kesar, A. Aharony, and G. Breitmeier manuscript received 20 February 2002; published 10 June 2002 The concept of a cyclotron-resonance maser CRM.40.Az I. INTRODUCTION Cyclotron resonance masers CRM's are well-known sources of high-power microwaves

Jerby, Eli

250

Two-dimensional cyclotron-resonance maser array: Spectral measurements with one and two electron beams  

E-print Network

Two-dimensional cyclotron-resonance maser array: Spectral measurements with one and two electron Received 8 September 1997; revised manuscript received 17 September 1998 The cyclotron-resonance-maser CRM Cyclotron-resonance masers CRMs and gyrotrons 1,2 have been developed so far as single-electron-beam tubes

Jerby, Eli

251

Radiation beam steering by cyclotron-resonance maser array Amit Kesar and Eli Jerby*  

E-print Network

Radiation beam steering by cyclotron-resonance maser array Amit Kesar and Eli Jerby* Faculty beaming by a cyclotron-resonance maser CRM array is presented theoretically. In this scheme, the CRM.40.Fd I. INTRODUCTION Cyclotron-resonance masers CRMs and gyrotrons 1,2 are well known as high

Jerby, Eli

252

Cold Electrostatic Ion Cyclotron Waves for Preionization and IBW Launching in LHD*  

E-print Network

- 1 - Cold Electrostatic Ion Cyclotron Waves for Preionization and IBW Launching in LHD* Masayuki CESICW (Cold Electrostatic Ion Cyclotron Wave) for heating the core of LHD with the folded waveguide to use for the E|| polarized folded waveguide is the cold electrostatic ion cyclotron wave (CESICW).2

253

Cold Electrostatic Ion Cyclotron Waves for Preionization and IBW Launching in LHD *  

E-print Network

­ 1 ­ Cold Electrostatic Ion Cyclotron Waves for Preionization and IBW Launching in LHD * Masayuki CESICW (Cold Electrostatic Ion Cyclotron Wave) for heating the core of LHD with the folded waveguide to use for the E || polarized folded waveguide is the cold electrostatic ion cyclotron wave (CESICW). 2

254

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

SciTech Connect

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.

Shidara, Hiroyuki [Kyoto University (Japan); Nagasaki, Kazunobu [Kyoto University (Japan); Sakamoto, Kinzo [Kyoto University (Japan)] (and others)

2004-01-15

255

Properties Of Waves At The Proton Cyclotron Frequency Upstream From Mars  

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

256

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

NASA Astrophysics Data System (ADS)

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.

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

257

Electrostatic ion cyclotron and ion plasma waves in a symmetric pair-ion plasma cylinder.  

PubMed

Complicated wave behavior observed in the cylindrical pair-ion (fullerene) experiments by Oohara and co-workers are now identified to be low harmonic ion cyclotron waves combined with ion plasma oscillations inherent to kinetic theory. The electrostatic dispersion equation derived is based on an approximation for the current from the exact solutions of the characteristic cylindrical geometry form of the Vlasov plasma equation in a uniform magnetized plasma cylinder surrounded by a larger metal boundary outside a vacuum gap, which thus differs from that in unbounded plasmas. Positive and negative ions, differing only in the sign of their charge, respond to a potential in the same time scale and cooperate to reflect the enhanced kinetic orbital behaviors to the macroscopic propagation characteristics. In addition, the experimental value of the Larmor radius (comparable to the discharge radius but small enough to make the analytic approximation useful) makes higher harmonic ion cyclotron effects both observable and calculable with the appropriate approximation for the kinetic theory. PMID:24679299

Kono, M; Vranjes, J; Batool, N

2014-03-14

258

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

NASA Astrophysics Data System (ADS)

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.

Pal, Gautam; DuttaGupta, Anjan; Chakrabarti, Alok

2014-07-01

259

Medical Device Safety  

MedlinePLUS

... Vaccines, Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products Medical Devices Print this page Share this page E-mail ... Medical Product Safety Network Emergency Situations (Medical Devices) Medical Device Safety Search the Medical Device Safety Section Medical ...

260

METEOR: medical tutor employing ontology for robustness  

Microsoft Academic Search

Problem based learning is becoming widely popular as an effective teaching method in medical education. Paying individual attention to a small group of students in medical PBL can place burden on the workload of medical faculty whose time is very costly. Intelligent tutoring systems offer a cost effective alternative in helping to train the students, but they are typically prone

Hameedullah Kazi; Peter Haddawy; Siriwan Suebnukarn

2011-01-01

261

The Electron Cyclotron Maser--An Historical Survey  

Microsoft Academic Search

It has taken nearly twenty years for practical development of the electron cyclotron maser. The initial theoretical notions were put forward by R. Q. Twiss in 1958, but the first clear experimental demonstration did not take place until 1964. Today, in the USSR, these devices are being built which deliver kilowatt-level CW power at submillimeter wavelengths with high efficiency. This

J. L. Hirshfield; V. L. Granatstein

1977-01-01

262

Special issue on Electron Cyclotron Wave physics and technology  

Microsoft Academic Search

In the editorial of the September issue of this year it was announced that a number of special issues of Nuclear Fusion will be published which will address subjects for which the integration of physics and enabling technology is essential. This November issue is dedicated to Electron Cyclotron Wave (ECW) physics and technology.This issue is a compilation of 25 papers

F. C. Schüller

2003-01-01

263

Nonlinear Cyclotron-Resonance Accelerations by a Generalized EM Wave  

E-print Network

). Unlike the usual transit-time accelerations e 00 v 1 this acceleration mechanism is independentNonlinear Cyclotron-Resonance Accelerations by a Generalized EM Wave AKIMOTO, Kazuhiro and HOJO accelerations by a 1D, EM, dispersive pulse in an external magnetic field are investigated. It is found

Boyer, Edmond

264

Foil changer for the Chalk River superconducting cyclotron  

Microsoft Academic Search

Capture of an injected beam in the Chalk River superconducting cyclotron requires that a carbon stripping foil be accurately placed in a dee to intercept the incoming beam. Foil radial position must be precisely adjustable and foils must be easily replaced. A foil changing apparatus has been designed, built and tested to meet these requirements. The main components are a

C. R. Hoffmann; R. I. Kilborn; J. E. Mouris; D. R. Proulx; J. F. Weaver

1985-01-01

265

RF cavity simulations for superconducting cyclotron C400  

NASA Astrophysics Data System (ADS)

Compact superconducting isochronous cyclotron C400 [ 1] has been designed at IBA (Belgium) in collaboration with the JINR (Dubna). This cyclotron will be the first cyclotron in the world capable of delivering protons, carbon and helium ions for therapeutic use. 12C6+ and 4He2+ ions will be accelerated to 400 MeV/u energy and extracted by electrostatic deflector, H{2/+} ions will be accelerated to the energy of 265 MeV/u and extracted by stripping. It is planned to use two normal conducting RF cavities for ion beam acceleration in the cyclotron C400. Computer model of the double gap delta RF cavity with 4 stems was developed in the general-purpose simulation software CST STUDIO SUITE. Necessary resonant frequency and increase of the voltage along the gaps were achieved. Optimization of the RF cavity parameters leads us to the cavity with quality factor about 14000, RF power dissipation is equal to about 50 kW per cavity.

Jongen, Y.; Abs, M.; Kleeven, W.; Zaremba, S.; Glazov, A. A.; Gurskiy, S. V.; Karamyshev, O. V.; Karamysheva, G. A.; Morozov, N. A.

2011-07-01

266

Ion heating by strong electrostatic ion cyclotron turbulence  

Microsoft Academic Search

A theory of ion heating due to electrostatic ion cyclotron (EIC) waves in the auroral zone is presented. Due to the slowly convecting nature of the EIC mode, quasi-linear plateau formation cannot stabilize the waves, and growth occurs until the nonlinear mechanisms of ion resonance broadening and electron trapping provide saturation. The large amplitude and coherent nature of the resulting

R. L. Lysak; M. K. Hudson; M. Temerin

1980-01-01

267

Status of ECR (Electron Cyclotron Resonance) source technology  

SciTech Connect

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.

Lyneis, C.M.

1987-03-01

268

Alternates to the Cyclotron for Heavy-Ion Acceleration  

NASA Astrophysics Data System (ADS)

The status and future possibilities for several alternates to the cyclotron for heavy-ion acceleration are discussed. Linear accelerators, both conventional and superconducting, tandem electrostatic accelerators, and the electron ring accelerator are among the accelerator types and concepts reviewed and compared.

Martin, J. A.

1972-07-01

269

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

SciTech Connect

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)

Not Available

1986-10-29

270

Excitation of cyclotron resonances from random fluctuations of stellarator windings  

Microsoft Academic Search

We have investigated the effect of random fluctuation of stellarator windings in a modified betatron accelerator configuration on the dynamics of the beam centroid by solving numerically the equations of motion. Our results show that random displacements of the windings by a few millimeters produce field errors that excite the cyclotron resonance modes that efficiently direct most of the input

E. Drakakis; D. Karabourniotis; C. A. Kapetanakos

1996-01-01

271

Ion cyclotron resonance studies of some reactions of N/+/ ions  

NASA Technical Reports Server (NTRS)

Product distributions and rate constants for the reactions of ground-state N(+) ions with CO, NO, CO2, and CH4 were measured. Rate constants were obtained using ion-cyclotron-resonance trapped-ion methods, and product distributions were obtained using a tandem (Dempster-ICR) mass spectrometer. Rapid nitrogen isotope exchange was also observed in N(+)-N2 collisions.

Anicich, V. G.; Huntress, W. T., Jr.; Futrell, J. H.

1977-01-01

272

Numerical simulation of unconstrained cyclotron resonant maser emission  

NASA Astrophysics Data System (ADS)

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 (AKR) -an intense rf emission sourced at high altitudes in the terrestrial auroral magnetosphere. PiC 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 to 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 2.68GHz, 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 radiation emission can be obtained from an electron horseshoe distribution in the absence of radiation boundaries.

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

2014-05-01

273

Medication Guide  

MedlinePLUS

... for heavy smokers. Prescription First-Line Medications: Other Bupropion Bupropion, also known as Zyban®, helps to reduce nicotine withdrawal symptoms and the urge to smoke. Bupropion can be used safely with nicotine replacement products. ...

274

Medical Imaging.  

ERIC Educational Resources Information Center

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)

Barker, M. C. J.

1996-01-01

275

Botox (Medical)  

MedlinePLUS

... from any list. Close without sharing. Give Us Feedback Botox (Medical) Your name First Name MI Laast ... Your message: Close without sending Thank you. Your feedback will help us improve this site. Close What ...

276

arXiv:cond-mat/9604010v11Apr1996 Vortex Dynamics in Superfluids: Cyclotron Type Motion  

E-print Network

arXiv:cond-mat/9604010v11Apr1996 Vortex Dynamics in Superfluids: Cyclotron Type Motion E. Demircan1. The natural motion of the vortex is of cyclotron type, whose frequency is found to be on the order of phonon foreign particles into the vortex core can reduce the cyclotron frequency and make the cyclotron motion

Niu, Qian

277

Medication Adherence  

Microsoft Academic Search

\\u000a A key component in the management of health-care conditions is the use of prescribed medications. The effectiveness of medications\\u000a and their long-term benefits depends on adherence to the prescriber’s instructions [1]. Adherence is defined as the extent\\u000a to which people follow the instructions they are given for prescribed treatments [2]; it involves consumer choice and is intended\\u000a to be non-judgmental,

Hayden B. Bosworth

278

Experimental and numerical investigation of auroral cyclotron maser processes  

NASA Astrophysics Data System (ADS)

When an electron beam with initial spread in rotational velocity 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 [1] and may be responsible for the generation of Auroral Kilometric Radiation (AKR) -- an intense RF emission sourced at high altitudes in the terrestrial auroral magnetosphere. In a scaled laboratory reproduction of this process, a 75-85keV electron beam of 5-40A was magnetically compressed by a system of solenoids and electromagnetic emissions observed for cyclotron frequencies of 4.42GHz and 11.7GHz [2]. A comparison of these experimental measurements with the results of 2D and 3D numerical simulations will be presented, showing the effect of cyclotron-wave detuning on the efficiency of forward and backward wave coupling. The experiment presently differs from the astrophysical case in that it has a well defined radiation boundary. PiC code calculations have been undertaken to investigate the dynamics of the cyclotron emission process in the absence of such metallic boundaries and incorporating a background plasma of variable density. Computations reveal that the cyclotron emission process persists although its spatial growth is reduced. A quenching of the instability is also apparent as the ratio ?ce / ?p is reduced to be < 1. This is consistent with the predictions of theory [3] and satellite observations that suggest AKR emission is localized within a region of plasma depletion where ?ce / ?p > 1. [4pt] [1] D. Gurnett, ``Waves in Space Plasmas'', 50th Annual meeting of the APS Division of Plasma Physics, 2008. [0pt] [2] K. Ronald et al, Physics of Plasmas, 15, 056503, 2008. [0pt] [3] R. Bingham and R. A. Cairns, Physics of Plasmas, 7, 3089, 2000.

Speirs, David

2009-11-01

279

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

SciTech Connect

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.

Amatucci, W.E.

1994-01-01

280

Trends of Medication Errors in Hospitalized Children  

Microsoft Academic Search

Medication errors are a major cause of morbidity and mortality among hospitalized children. Due to the small volumes of stock solution involved, even a large error may look as an unsuspiciously small dose. Strategies were implemented to reduce medication errors in a large tertiary pediatric hospital in Toronto. Starting in 1993, several initiatives were taken, including a newhospital computer system

Gideon Koren

2002-01-01

281

Cyclotron resonance study of quasiparticle mass and scattering rate in the hidden-order and superconducting phases of URu2Si2  

NASA Astrophysics Data System (ADS)

The observation of cyclotron resonance in ultraclean crystals of URu2Si2 [S. Tonegawa et al., Phys. Rev. Lett. 109, 036401 (2012), 10.1103/PhysRevLett.109.036401] provides another route besides quantum oscillations to the determination of the bulk electronic structure in the hidden-order phase. We report detailed analyses of the resonance lines, which fully resolve the cyclotron mass structure of the main Fermi surface sheets. A particular focus is given to the anomalous splitting of the sharpest resonance line near the [110] direction under in-plane magnetic-field rotation, which implies peculiar electronic structure in the hidden-order phase. The results under the field rotation from [110] toward [001] direction reveal that the splitting is a robust feature against field tilting from the basal plane. This is in sharp contrast to the reported frequency branch ? in the quantum oscillation experiments showing a three-fold splitting that disappears by a small field tilt, which can be explained by the magnetic breakdown between the large hole sphere and small electron pockets. Our analysis of the cyclotron resonance profiles reveals that the heavier branch of the split line has a larger scattering rate, providing evidence for the existence of hot-spot regions along the [110] direction. These results are consistent with the broken fourfold rotational symmetry in the hidden-order phase, which can modify the interband scattering in an asymmetric manner. We also extend our measurements down to 0.7 K, which results in the observation of cyclotron resonance in the superconducting state, where novel effects of vortex dynamics may enter. We find that the cyclotron mass undergoes no change in the superconducting state. In contrast, the quasiparticle scattering rate shows a rapid decrease below the vortex-lattice melting transition temperature, which supports the formation of quasiparticle Bloch state in the vortex lattice phase.

Tonegawa, S.; Hashimoto, K.; Ikada, K.; Tsuruhara, Y.; Lin, Y.-H.; Shishido, H.; Haga, Y.; Matsuda, T. D.; Yamamoto, E.; Onuki, Y.; Ikeda, H.; Matsuda, Y.; Shibauchi, T.

2013-12-01

282

Indiana University cyclotron facility Back by popular demand are guided tours of the IU cyclotron facility, a  

E-print Network

(MPRI), one of only six facilities in the nation that offers proton radiation therapy. Tours the energetic proton beams are precisely steered in order to destroy diseased tissue in a patient, while of Energy and Matter, and IU Cyclotron Operations, which supports the Midwest Proton Radiotherapy Institute

Evans, Hal

283

Dittrick Medical History Center  

NSDL National Science Digital Library

Currently operating as an interdisciplinary study center within the College of Arts and Sciences of Case Western Reserve University, the Dittrick Medical History Center was established as part of the Cleveland Medical Library Association in 1894. First-time visitors will definitely want to begin by looking through the museum's history, and then examine the museum artifacts and galleries, which represent a small sample of their holdings. The artifacts are divided into time periods and include such fascinating medical equipment as bloodletting devices, a phrenology bust, and a defribrillator from 1950. The galleries section allows visitors to take a virtual tour of the rooms within the museum, such as a doctor's office from the 1930s and a replica of a pharmacy from the 1880s. Several online exhibits are also available for perusal, such as one dedicated to Cleveland's brush with a smallpox epidemic in 1902. Utterly fascinating, though not for the squeamish, is the exhibit that details medical school photographs, many of them class photographs around dissection tables, and postcards featuring medical students and cadavers. The site is rounded out with a host of online guides and finding aids that help in using the Center's extensive collections dealing with the history of medicine.

2003-01-01

284

Effect of turbulence on electron cyclotron current drive and heating in ITER  

NASA Astrophysics Data System (ADS)

Non-linear local electromagnetic gyrokinetic turbulence simulations of the ITER standard scenario H-mode are presented for the q = 3/2 and q = 2 surfaces. The turbulent transport is examined in regions of velocity space characteristic of electrons heated by electron-cyclotron waves. Electromagnetic fluctuations and sub-dominant micro-tearing modes are found to contribute significantly to the transport of the accelerated electrons, even though they have only a small impact on the transport of the bulk species. The particle diffusivity for resonant passing electrons is found to be less than 0.15 m2 s?1, and their heat conductivity is found to be less than 2 m2 s?1. Implications for the broadening of the current drive and energy deposition in ITER are discussed.

Casson, F. J.; Poli, E.; Angioni, C.; Buchholz, R.; Peeters, A. G.

2015-01-01

285

Cyclotron resonance of single-valley Dirac fermions in nearly gapless HgTe quantum wells  

NASA Astrophysics Data System (ADS)

We report on Landau level spectroscopy studies of two HgTe quantum wells (QWs) near or at the critical well thickness, where the band gap vanishes. In magnetic fields up to B =16 T, oriented perpendicular to the QW plane, we observe a ?B dependence for the energy of the dominant cyclotron resonance (CR) transition characteristic of two-dimensional Dirac fermions. The dominant CR line exhibits either a single or double absorption line shape for the gapless or gapped QW. Using an effective Dirac model, we deduce the band velocity of single-valley Dirac fermions in gapless HgTe quantum wells, vF=6.4×105 m/s, and interpret the double absorption of the gapped QW as resulting from the addition of a small relativistic mass.

Ludwig, J.; Vasilyev, Yu. B.; Mikhailov, N. N.; Poumirol, J. M.; Jiang, Z.; Vafek, O.; Smirnov, D.

2014-06-01

286

Nonlinear response of magnetic islands to localized electron cyclotron current injection  

SciTech Connect

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.

Borgogno, D. [Dipartimento di Fisica, Università di Pisa, Pisa (Italy); Dipartimento Energia, Politecnico di Torino, Torino (Italy); Comisso, L.; Grasso, D. [Dipartimento Energia, Politecnico di Torino, Torino (Italy); Istituto Sistemi Complessi—CNR, Roma (Italy); Lazzaro, E. [Istituto di Fisica del Plasma “P.Caldirola,” Associazione Euratom-ENEA-CNR, Milano (Italy)

2014-06-15

287

Finite-width currents, magnetic shear, and the current-driven ion-cyclotron instability  

NASA Technical Reports Server (NTRS)

Our earlier results that non-local effects due to even a small magnetic shear produce a significant reduction of the growth rate of the ion cyclotron instability driven by a uniform current are now generalized to finite width currents. Externally prescribed as well as self-consistent shears are considered. If the current width Lc exceeds the shear length Ls, the previous results are recovered. Shear becomes less effective with reduction of Lc, and for typical parameters, the growth rate attains its (shearless) local value for Lc/Ls approximately less than 10 to the minus 2. Non-local effects of the finite current width itself come into play if Lc is further reduced to a few ion Larmor radii and can quench the instability. Previously announced in STAR as N83-28996

Bakshi, P.; Ganguli, G.; Palmadesso, P.

1983-01-01

288

Magnetic field calculation for a 10 MeV positron emission tomography cyclotron  

SciTech Connect

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.

Chen Dezhi; Liu Kaifeng; Yang Jun; Li Dong; Qin Bin; Xiong Yongqian [State Key Lab of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Chen Zihao [Central Southern Electrical Power Design Institute, Wuhan 430071 (China)

2013-05-15

289

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

DOEpatents

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)

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

1975-08-01

290

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

NASA Technical Reports Server (NTRS)

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.

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

1970-01-01

291

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

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.

Chen Ming [Department of Radiation Oncology, University of Michigan Health System, Ann Arbor, MI (United States); Hayman, James A. [Department of Radiation Oncology, University of Michigan Health System, Ann Arbor, MI (United States); Haken, Randall K. ten [Department of Radiation Oncology, University of Michigan Health System, Ann Arbor, MI (United States); Tatro, Daniel [Department of Radiation Oncology, University of Michigan Health System, Ann Arbor, MI (United States); Fernando, Shaneli [Department of Radiation Oncology, Veterans Administration Medical Center, Ann Arbor, MI (United States); Kong, F.-M. [Department of Radiation Oncology, University of Michigan Health System, Ann Arbor, MI (United States) and Department of Radiation Oncology, Veterans Administration Medical Center, Ann Arbor, MI (United States)]. E-mail: fengkong@med.umich.edu

2006-01-01

292

Medical genetics  

SciTech Connect

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.

Jorde, L.B.; Carey, J.C.; White, R.L.

1995-10-01

293

Medical leasing.  

PubMed

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

Holden, Elizabeth A

2012-01-01

294

Medical Instrumentation  

NSDL National Science Digital Library

Students learn about the sorts of devices designed by biomedical engineers and the many other engineering specialties that are required in their design of medical diagnostics, therapeutic aids, surgical devices and procedures, and replacement parts. They discuss the special considerations that must be made when dealing with the human body, such as being minimally invasive, biocompatible, keeping sterile, lightweight, corrosion resistant, long lasting and electrically safe. They also explore how "form fits function." Students gain an appreciation for the amazing devices that improve our quality of life. This lesson serves as a starting point for students to begin to ponder how the medical devices in their everyday lives work.

Techtronics Program,

295

Electromagnetic ion cyclotron waves at proton cyclotron C. C. Chaston, J. W. Bonnell, J. P. McFadden, R. E. Ergun, and C. W. Carlson  

E-print Network

: Auroral phenomena (2407); 2772 Magnetospheric Physics: Plasma waves and instabilities; 6984 Radio Science they are electromagnetic. As these waves travel up the fieldline, the normalized wave fre- quency w/p increases owingElectromagnetic ion cyclotron waves at proton cyclotron harmonics C. C. Chaston, J. W. Bonnell, J

California at Berkeley, University of

296

Recent Medical Device Recalls  

MedlinePLUS

... Vaccines, Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products Medical Devices Print this page Share this page E-mail this page Home Medical Devices Medical Device Safety Medical Device Recalls Medical Device ...

297

Kinetic friction attributed to enhanced radiation by cyclotron maser instability  

NASA Technical Reports Server (NTRS)

Along the auroral field lines, a fraction of the energetic electrons injected from the magnetotail is reflected by the earth's convergent geomagnetic field. The reflected loss-cone electrons are unstable with respect to the cyclotron maser instability, resulting in the auroral kilometric radiation. This paper investigates the kinetic friction force exerted on the energetic electrons by the enhanced radiation field. It is found that the enhanced radiation results in a deceleration of reflected electrons, thereby providing an effective resistivity. In addition, the rate of decrease (increase) of effective perpendicular (parallel) kinetic temperatures is also evaluated. The analysis is carried out over various physical parameters such as the degree of loss cone, average particle energy, and the ratio of plasma frequency to cyclotron frequency.

Yoon, Peter H.; Wu, C. S.

1991-01-01

298

Proton-cyclotron and firehose instabilities in inhomogeneous plasmas  

NASA Astrophysics Data System (ADS)

By combining the kinetic-fluid model for macroscopic quantities and quasilinear kinetic theory for microscopic plasma instabilities, the present paper investigates quasi-stationary spatial distribution and characteristics of the electromagnetic proton-cyclotron and parallel firehose instabilities in inhomogeneous plasma, as well as their influence on macroscopic variables. The present paper considers diverging magnetic field along a flux tube, as well as the associated density model, with various source region boundary conditions, in order to investigate the spatial locations at which the excitation, saturation, and damping of the proton-cyclotron and firehose instabilities occur in a medium with field-aligned inhomogeneity. Potential application may be on the solar wind model in which the temperature anisotropy threshold rigorously follows as a result of quasilinear relaxation process.

Yoon, Peter H.; Seough, Jungjoon

2014-09-01

299

Loss-cone-driven ion cyclotron waves in the magnetosphere  

NASA Technical Reports Server (NTRS)

The study examines the theoretical properties of linear ion cyclotron waves propagating in the magnetosphere at arbitrary angles to the background magnetic field. It is found that in some cases the linear wave growth of modes with oblique propagation can dominate that of the parallel propagating electromagnetic ion cyclotron (EMIC) wave. The growth rate of the loss-cone-driven mode depends strongly on the depth of the loss cone. A simple analytical theory which explains the scaling of the growth rate of the oblique mode with respect to various parameters is presented. The loss-cone-driven mode is an electromagnetic mode which is preferentially nearly linearly polarized. The wave field which results from the oblique mode in its perferentially nearly linearly polarized form are nearly perpendicular to B0 and are such that they may be difficult to distinguish from those of a linearly polarized parallel propgating EMIC wave.

Denton, Richard E.; Hudson, Mary K.; Roth, Ilan

1992-01-01

300

PHYSICS OF ELECTRON CYCLOTRON CURRENT DRIVE ON DIII-D  

SciTech Connect

OAK A271 PHYSICS OF ELECTRON CYCLOTRON CURRENT DRIVE ON DIII-D. Recent experiments on the DIII-D tokamak have focused on determining the effect of trapped particles on the electron cyclotron current drive (ECCD) efficiency. The measured ECCD efficiency increases as the deposition location is moved towards the inboard midplane or towards smaller minor radius for both co and counter injection. The measured ECCD efficiency also increases with increasing electron density and/or temperature. The experimental ECCD is compared to both the linear theory (Toray-GA) as well as a quasilinear Fokker-Planck model (CQL3D). The experimental ECCD is found to be in better agreement with the more complete Fokker-Planck calculation, especially for cases of high rf power density and/or loop voltage.

PETTY,CC; PRATER,R; LUCE,TC; ELLIS,RA; HARVEY,RW; KINSEY,JE; LAO,LL; LOHR,J; MAKOWSKI,MA

2002-11-01

301

Electrostatic ion-cyclotron waves in magnetospheric plasmas Nonlocal aspects  

NASA Technical Reports Server (NTRS)

The importance of the effect of the magnetic shear and the finite size of current channel on the electrostatic ion-cyclotron instability for the space plasmas is illustrated. A non-local treatment is used. When the channel width Lc, is larger than the shear length Ls, there is a large reduction in the growth rate along with a noteworthy reduction of the band of the unstable perpendicular wavelengths. For Lc less than or = Ls/10 the growth rate is not much altered from its local value, however for Lc/pi i less than or = 10 to the second power the growth rate starts falling below the local value and vanishes for Lc pi i. The non-local effects lead to enhanced coherence in the ion cyclotron waves. Previously announced in STAR as N84-14917

Ganguli, G.; Bakshi, P.; Palmadesso, P.

1984-01-01

302

Radiation protection aspects of the operation in a cyclotron facility  

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

303

[Medical geography].  

PubMed

Hippocrates already noted that geographical factors such as climate, relief, geology but also settlement patterns had influenced the distribution of diseases. The task of medical geography is to investigate the associations between geographical factors and diseases. Thereby, geographic techniques and concepts are applied on health problems. Of particular importance is the mapping of diseases whose causes are environmental-related. In addition, epidemiological, ecological but also social scientific studies play an important part in the investigation of the associations between geographical factors and diseases. In order to understand the associations between the spatial distribution of diseases and environmental exposures, geographic information systems as well as statistical analyses have recently become more important. Some authors regard medical geography merely as supporting discipline of medicine. Nevertheless, as men and environment future and as they play an important part in the diffusion of diseases being regarded as defeated, medical geography will play an important part concerning medical questions. Especially travel medicine will rely on geographic knowledge, if a patient has to be consulted who plans to travel to an unknown country of which knowledge on the geographical distribution and ecology of diseases will be necessary. PMID:17974122

Hauri, D

2007-10-17

304

Medical genetics  

SciTech Connect

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.

Nora, J.J.; Fraser, F.C.

1989-01-01

305

Medical kits for business travellers.  

PubMed

A survey of occupational physicians of the Food Industry Medical Officers Group was undertaken to establish details of medical kits supplied by their organizations to business travellers. The most common approach was an in-house medical kit with instructions emphasizing self treatment of the common ailments of travellers such as motion sickness, sleeplessness, diarrhoea, indigestion and headaches. The majority of kits included a small supply of needles, syringes, IV cannulae etc either in a commercial 'Aids Kit' or as inhouse supplies. Antimalarials were provided either as a standard kit item or as required. About half provided antibiotics for the self treatment of infections. Very few provided a telephone number for use in the event of medical emergencies. A standard medical kit specification is proposed. PMID:2214691

Deacon, S P; McCulloch, W J

1990-01-01

306

RF physics of ICWC discharge at high cyclotron harmonics  

SciTech Connect

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,?=?{sub H+}, and with its high cyclotron harmonics (HCH), ?=10?{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.

Lyssoivan, A.; Van Eester, D.; Wauters, T.; Vervier, M.; Van Schoor, M. [Association Euratom-Belgian State, LPP-ERM-KMS, 1000 Brussels (Belgium); Bobkov, V.; Rohde, V.; Schneider, P. [Association Euratom-IPP, Max-Planck Institut für Plasmaphysik, 85748 Garching (Germany); Douai, D.; Kogut, D. [Association Euratom-CEA, CEA, IRFM, 13108 St Paul lez Durance (France); Kreter, A.; Möller, S.; Philipps, V.; Sergienko, G. [Association Euratom-IEK-4, Forschungszentrum Jülich, 52425 Jülich (Germany); Moiseenko, V. [Institute of Plasma Physics NSC KIPT, 61108 Kharkiv (Ukraine); Noterdaeme, J.-M. [Association Euratom-IPP, Max-Planck Institut für Plasmaphysik, 85748 Garching, Germany and Ghent University, 9000 Ghent (Belgium); Collaboration: TEXTOR Team; ASDEX Upgrade Team

2014-02-12

307

Vanishing of Cyclotron Resonance in Correlated 2D Electron Systems  

Microsoft Academic Search

Experimental measurements of photoresistivity under terahertz (THz) radiation in low magnetic fields at conditions of cyclotron resonance (CR) in two-dimensional electron system (2DES) of GaAs\\/AlGaAs nanostructures are presented and discussed. We report the experimental discovery of CR-vanishing effect (CRV) in GaAs\\/AlGaAs heterostructures with high mobility as a well-defined gap on CR-line that is independent on incident THz power. Our analysis

Andre Chebotarev; Galina Chebotareva

2009-01-01

308

Hadronic Cross sections: from cyclotrons to colliders to cosmic rays  

E-print Network

We present evidence for the saturation of the Froissart bound at high energy for {\\em all hadronic} total cross sections at high energies, and use this to unify $pp$ (and $\\bar p p$) total cross sections over the energy range from cyclotrons to colliders to ultra-high energy cosmic rays, an energy span from $\\sqrt s = 4$ GeV to 80 TeV.

Martin M. Block

2010-09-02

309

RF physics of ICWC discharge at high cyclotron harmonics  

NASA Astrophysics Data System (ADS)

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,?=?H+, and with its high cyclotron harmonics (HCH), ?=10?cH+? 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.

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

310

Slant Slot Antenna-Type Electron Cyclotron Resonance Plasma Source  

Microsoft Academic Search

A new compact electron cyclotron resonance (ECR) plasma source, which is termed slant-slot antenna-type ECR plasma source, is presented. Using this plasma source an ion saturation current density Iis of 6.2 mA\\/cm2±5.2% was obtained over a diameter of 300 mm under ambient conditions of Cl2 gas at 0.7 Pa. The features of the plasma source are an independent circular TM011

Seiichi Watanabe; Hitoshi Tamura; Masahiro Sumiya; Muneo Furuse; Sunao Kawasaki

1998-01-01

311

Pencil Beam Scanning System Based On A Cyclotron  

NASA Astrophysics Data System (ADS)

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.

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

2011-06-01

312

Collective cyclotron resonance of an inhomogeneous electron gas  

Microsoft Academic Search

We report low-temperature far-infrared magneto-optical measurements on a remotely doped, asymmetric, wide parabolic AlxGa1-xAs quantum well with two curvatures. The collective cyclotron-resonance spectrum of the system, measured with an in-plane magnetic field, is found to depend on the electron areal density Ns. At sufficiently high Ns, so that the effective layer thickness is much larger than the magnetic length, two

X. Ying; K. Karraï; H. D. Drew; M. Santos; M. Shayegan

1992-01-01

313

Converting an AEG Cyclotron to H? Acceleration and Extraction  

NASA Astrophysics Data System (ADS)

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.

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

2009-03-01

314

Resonant Cyclotron Scattering and Comptonization in Neutron Star Magnetospheres  

E-print Network

Resonant cyclotron scattering of the surface radiation in the magnetospheres of neutron stars may considerably modify the emergent spectra and impede efforts to constraint neutron star properties. Resonant cyclotron scattering by a non-relativistic warm plasma in an inhomogeneous magnetic field has a number of unusual characteristics: (i) in the limit of high resonant optical depth, the cyclotron resonant layer is half opaque, in sharp contrast to the case of non-resonant scattering. (ii) The transmitted flux is on average Compton up-scattered by ~ $1+ 2 beta_T$, where $\\beta_T$ is the typical thermal velocity in units of the velocity of light; the reflected flux has on average the initial frequency. (iii) For both the transmitted and reflected fluxes the dispersion of intensity decreases with increasing optical depth. (iv) The emergent spectrum is appreciably non-Plankian while narrow spectral features produced at the surface may be erased. We derive semi-analytically modification of the surface Plankian emission due to multiple scattering between the resonant layers and apply the model to anomalous X-ray pulsar 1E 1048.1--5937. Our simple model fits just as well as the ``canonical'' magnetar spectra model of a blackbody plus power-law.

Maxim Lyutikov; Fotis P. Gavriil

2005-07-22

315

High Power Ion Cyclotron Heating in the VASIMR  

NASA Astrophysics Data System (ADS)

The Variable Specific Impulse Magnetoplasma Rocket (VASIMR®) is an electric propulsion system under development at Ad Astra Rocket Company that utilizes several processes of ion acceleration and heating that occur in the Birkeland currents of an auroral arc system. Among these processes are parallel electric field acceleration, lower hybrid resonance heating, and ion cyclotron resonance heating. The VASIMR® is capable of laboratory simulation of electromagnetic ion cyclotron wave heating during a single pass of ions through the resonance region. The plasma is generated by a helicon discharge of 35 kW then passes through a 176 kW RF booster stage that couples left hand polarized slow mode waves from the high field side of the resonance. VX-200 auroral simulation results from the past year are discussed. Ambipolar acceleration has been shown to produce 35eV argon ions in the helicon exhaust. The effects on the ion exhaust with an addition of 150-200 kW of ion cyclotron heating are presented. The changes to the VASIMR® experiment at Ad Astra Rocket Company's new facility in Webster, Texas will also be discussed, including the possibility of collaborative experiments.

Longmier, B. W.; Brukardt, M. S.; Bering, E. A.; Chang Diaz, F.; Squire, J.

2009-12-01

316

A Suzaku View of Cyclotron Line Sources and Candidates  

NASA Technical Reports Server (NTRS)

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.

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

317

Electromagnetic ion beam instabilities - Growth at cyclotron harmonic wave numbers  

NASA Technical Reports Server (NTRS)

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.

Smith, Charles W.; Gary, S. Peter

1987-01-01

318

Foil changer for the Chalk River superconducting cyclotron  

SciTech Connect

Capture of an injected beam in the Chalk River superconducting cyclotron requires that a carbon stripping foil be accurately placed in a dee to intercept the incoming beam. Foil radial position must be precisely adjustable and foils must be easily replaced. A foil changing apparatus has been designed, built and tested to meet these requirements. The main components are a supply magazine, a transport system, and unloading and loading mechanisms. The magazine is on top of the cyclotron. It holds 300 foils and can be isolated from machine vacuum for refilling. Each foil is mounted on a stainless steel frame. A stainless steel roller chain fitted with 33 copper sleeves (shrouds) carries foils, one per shroud, down a dee stem to the midplane. A 12-bit absolute optical shaft encoder senses foil position. To replace a foil a shroud is positioned at the top of the cyclotron, a foil is removed, and another is transferred from the magazine to the empty shroud. Three stepping motors and associated electronics provide mechanical drive and are interfaced with a CAMAC control system.

Hoffmann, C.R.; Kilborn, R.I.; Mouris, J.E.; Proulx, D.R.; Weaver, J.F.

1985-10-01

319

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

NASA Astrophysics Data System (ADS)

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).

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

2012-12-01

320

Utilization of the CS-30 cyclotron at the Duke University Medical Center  

SciTech Connect

Present routine radionuclide production includes {sup 18}F fluoride from protons on {sup 18}O water, {sup 13}N ammonia from protons on {sup 13}C slurry, {sup 15}O water from deuterons on nitrogen gas, and {sup 211}At from alphas on bismuth metal. Clinical PET using two tomographs (GE 4096 and Advance) is done Tuesday through Friday, typically 4 to 11 patients per day using {sup 15}O water, {sup 13}N ammonia, and {sup 18}F FDG synthesized with a GE Microlab. Clinical patient studies are 50% neurology using FDG, 45% body using FDG, and 5% cardiology using ammonia and FDG (oncology in these three areas totals 60%). {sup 15}O water for clinical research patients (THC and cognitive) is produced twice a week. {sup 211}At is produced about twice a week for monoclonal antibody labelling.

Wieland, B.W.; McKinney, C.J.; Dailey, M.F. [Duke Univ., Durham, NC (United States)

1994-12-31

321

Status of a compact electron cyclotron resonance ion source for National Institute of Radiological Sciences-930 cyclotron  

SciTech Connect

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 ?A for proton and deuteron, 50 ?A 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.

Hojo, S., E-mail: s-hojo@nirs.go.jp; Katagiri, K.; Nakao, M.; Sugiura, A.; Muramatsu, M.; Noda, A.; Noda, K. [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba (Japan)] [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba (Japan); Okada, T.; Takahashi, Y.; Komiyama, A.; Honma, T. [Accelerator Engineering Corporation, 6-18-1 Konakadai, Inage, Chiba (Japan)] [Accelerator Engineering Corporation, 6-18-1 Konakadai, Inage, Chiba (Japan)

2014-02-15

322

Status of a compact electron cyclotron resonance ion source for National Institute of Radiological Sciences-930 cyclotron.  

PubMed

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(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 ?A for proton and deuteron, 50 ?A for C(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. PMID:24593538

Hojo, S; Katagiri, K; Nakao, M; Sugiura, A; Muramatsu, M; Noda, A; Okada, T; Takahashi, Y; Komiyama, A; Honma, T; Noda, K

2014-02-01

323

Status of a compact electron cyclotron resonance ion source for National Institute of Radiological Sciences-930 cyclotron  

NASA Astrophysics Data System (ADS)

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 C4+ 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 ?A for proton and deuteron, 50 ?A for C4+, 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.

Hojo, S.; Katagiri, K.; Nakao, M.; Sugiura, A.; Muramatsu, M.; Noda, A.; Okada, T.; Takahashi, Y.; Komiyama, A.; Honma, T.; Noda, K.

2014-02-01

324

Beam current oscillations driven by cyclotron instabilities in a minimum-B electron cyclotron resonance ion source plasma  

NASA Astrophysics Data System (ADS)

Experimental observation of cyclotron instabilities in a minimum-B confined electron cyclotron resonance ion source plasma is reported. The instabilities are associated with strong microwave emission and a burst of energetic electrons escaping the plasma, and explain the periodic ms-scale oscillation of the extracted beam currents. Such non-linear effects are detrimental for the confinement of highly charged ions due to plasma perturbations at shorter periodic intervals in comparison with their production time. It is shown that the repetition rate of the periodic instabilities in oxygen plasmas increases with increasing magnetic field strength and microwave power and decreases with increasing neutral gas pressure, the magnetic field strength being the most critical parameter. The occurrence of plasma turbulence is demonstrated to restrict the parameter space available for the optimization of extracted currents of highly charged ions.

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

2014-04-01

325

A new design of truly selfshielding baby-cyclotrons for positron emitter production  

Microsoft Academic Search

The successful design of the Cyclone 30, a 30-MeV H- cyclotron, gave birth to an original design of truly selfshielding baby-cyclotrons dedicated to positron emitter production. This new negative ion cyclotron will deliver 10-MeV protons and 5-MeV deuterons. Up to eight targets are located inside the circular return yoke of the magnet, which serves as a primary neutron and gamma-ray

M. Abs; J. L. Bol; A. Chevalier; E. Conrad; Y. Jongen; M. Lacroix; G. Lannoye; T. Ledocte; A. Ninane; G. Rijckewaert; S. Zaremba

1989-01-01

326

Monte Carlo simulation of cyclotron resonant scattering features  

NASA Astrophysics Data System (ADS)

In the regime of very high magnetic fields on the order of 10(12} mathrm{G) the electron momenta perpendicular to the field are quantized due to the discrete Landau levels populated by the electrons. Parallel to the magnetic field the electrons form a continuous momentum distribution. The seed photon continuum is generated for example by bremsstrahlung or blackbody radiation. Resonant scattering of a seed photon by an electron may excite the electron to a higher Landau level. The subsequent de-excitation of the excited electron produces additional photons close to the resonance energy. This way complex cyclotron resonant scattering features (CRSFs) are imprinted on the continuum radiation. Due to the continuous electron momentum distribution parallel to the magnetic field the scattering photon's energy and angle are mixed by Lorentz transformation to the electron rest frame in which the resonant scattering process is being carried out. Therefore synthetic spectra of cyclotron lines can not be accurately calculated analytically. CRSFs have been observed in more than a dozen accreting X-ray binaries. They provide much information about the accretion structure in the observed systems since the exact line shape is sensitive to many parameters in the column. Typical parameters are for example the geometry and the spectral properties of seed photon sources, the geometry of the column, or the magnetic field and temperature within the column. We present an overview over the Monte-Carlo approach to cyclotron line simulation and show results from our texttt{cyclosim} code. Furthermore we investigate the influence of the accretion geometry on the cyclotron line shape. Our code enables us to perform fully relativistic simulations including the correct cyclotron scattering cross sections and the possibility to cope with parameter gradients such as magnetic field, temperature, or velocity gradients within the accretion column. Using a Green's function approach these simulations can be turned into XSPEC models which can be used to rapidly generate model spectra for arbitrary input continua. This is necessary for fitting the model to observed X-ray binary spectra in order to connect the simulated model to observable systems.

Schwarm, Fritz-Walter; Schönherr, Gabriele; Wilms, Joern

327

Linear and nonlinear physics of the magnetoacoustic cyclotron instability of fusion-born ions in relation to ion cyclotron emission  

SciTech Connect

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.

Carbajal, L., E-mail: L.Carbajal-Gomez@warwick.ac.uk; Cook, J. W. S. [Centre for Fusion, Space and Astrophysics, Department of Physics, The University of Warwick, Coventry CV4 7AL (United Kingdom)] [Centre for Fusion, Space and Astrophysics, Department of Physics, The University of Warwick, Coventry CV4 7AL (United Kingdom); Dendy, R. O. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB, Oxfordshire (United Kingdom) [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB, Oxfordshire (United Kingdom); Centre for Fusion, Space and Astrophysics, Department of Physics, The University of Warwick, Coventry CV4 7AL (United Kingdom); Chapman, S. C. [Centre for Fusion, Space and Astrophysics, Department of Physics, The University of Warwick, Coventry CV4 7AL (United Kingdom) [Centre for Fusion, Space and Astrophysics, Department of Physics, The University of Warwick, Coventry CV4 7AL (United Kingdom); Department of Mathematics and Statistics, University of Tromsø, N-9037, Tromsø (Norway); Max Planck Institute for the Physics of Complex Systems, D-01187, Dresden (Germany)

2014-01-15

328

Medical Dictionary  

NSDL National Science Digital Library

For nurses and other health care professionals who seek to distinguish the habitus from the humerus, this online medical dictionary provided by MedicineNet will be a place to bookmark for repeat visits. The dictionary contains well-written explanations for over 16,000 medical terms, and users can go ahead and browse around, or enter keywords or phrases into the search engine that resides on the page. The site also features a âÂÂWord of the DayâÂÂ, and visitors can also look through recent news items that address different health issues and also look over the latest entries to the dictionary. The site is rounded out by a list of the âÂÂTop 10 MedtermsâÂÂ, which is also a good way to start exploring the materials here.

2007-03-31

329

Medical Thoracoscopy  

Microsoft Academic Search

As opposed to ‘video-assisted thoracoscopic surgery’ which requires general anesthesia, double-lumen tracheal intubation and single lung ventilation, medical thoracoscopy (or ‘pleuroscopy’) is frequently performed in the respiratory endoscopy suite using local anesthesia. It can be done by well-trained physicians, either pulmonologists or thoracic surgeons, and its main indication is related to diagnosis and treatment of pleural effusions. Also, pneumothorax can

Francisco Rodríguez-Panadero

2008-01-01

330

Medical manslaughter.  

PubMed

On November 29, 2011 Dr Conrad Murray was sentenced to four years in prison after being convicted of the involuntary manslaughter of Michael Jackson. Expert witness statements indicated that Murray's actions were an "extreme departure from the standard of care", particularly with regard to (1) inappropriately treating insomnia with a surgical anaesthetic (propofol); (2) failing to acquire sufficiently informed consent; (3) administering propofol without the necessary monitoring equipment; (4) delaying contacting the emergency services; and (5) making ineffective resuscitation efforts. Further medical evidence argued that Murray's care of Jackson contained "17 egregious violations", defined as acts that posed a foreseeable danger to the patient's life. These deficiencies, it was stated, constituted gross negligence. Such events might seem remote from daily medical practice in Ireland. However, medical errors resulting in patient death are reported to be unfortunately frequent, even if such fatalities are rarely as dramatic, or as public, as that of Michael Jackson. Medical care is not necessarily straightforward, and any treatment outcome is dependent on clinician skill, the nature of the intervention, and on the pathological condition of the patient. Regardless of these latter two factors, a poor outcome still may occur through physician omissions or the commission of errors or violations. Merry and McCall Smith distinguish between errors and violations on the following basis: (1) errors are not deliberate, and result in unintentional actions and consequences; (2) violations, on the other hand, entail a deliberate deviation from accepted rules or norms. It was alleged that much of Dr Murray's professional conduct in this case fell into the latter category. PMID:23472376

Lyons, B

2013-01-01

331

Medical Applications  

NASA Astrophysics Data System (ADS)

In re-listening to the lectures of Charles Townes shortly after the invention of the laser (e.g., in the Boston Science Museum), one can already have a realistic vision of the potentialities of this new tool in the field of medical therapy, as evidenced by the use of the laser in ophthalmology to cure retinal detachment in the 1960's. Since then, applications have flourished in the domain of therapy. We will thus illustrate here only some of the main fields of application of medical lasers. On the opposite, the use of lasers in medical imaging is, with one exception in ophthalmology, still at the development level. It is becoming a diagnostic tool in addition to high performance imaging facilities that are often very expensive (such as CT scan, Magnetic Resonance Imaging (MRI) and nuclear imaging). Even if progress is sometimes slow, one can now image with light inside the human body, in spite of the strong scattering of light by tissues, in the same way as a pathologist sees surgical specimens.

Boccara, A. Claude; Mordon, Serge

2015-10-01

332

Low energy cyclotron production of multivalent transition metals for PET imaging and therapy  

NASA Astrophysics Data System (ADS)

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.

Avila-Rodriguez, Miguel Angel

333

Statistical analysis of relativistic electron energies for cyclotron resonance with EMIC waves observed on CRRES  

NASA Astrophysics Data System (ADS)

Electromagnetic ion cyclotron (EMIC) waves which propagate at frequencies below the proton gyrofrequency can undergo cyclotron resonant interactions with relativistic electrons in the outer radiation belt and cause pitch-angle scattering and electron loss to the atmosphere. Typical storm-time wave amplitudes of 1-10 nT cause strong diffusion scattering which may lead to significant relativistic electron loss at energies above the minimum energy for resonance, Emin. A statistical analysis of over 800 EMIC wave events observed on the CRRES spacecraft is performed to establish whether scattering can occur at geophysically interesting energies (?2 MeV). While Emin is well above 2 MeV for the majority of these events, it can fall below 2 MeV in localized regions of high plasma density and/or low magnetic field (fpe/fce,eq > 10) for wave frequencies just below the hydrogen or helium ion gyrofrequencies. These lower energy scattering events, which are mainly associated with resonant L-mode waves, are found within the magnetic local time range 1300 < MLT < 1800 for L > 4.5. The average wave spectral intensity of these events (4-5 nT2/Hz) is sufficient to cause strong diffusion scattering. The spatial confinement of these events, together with the limited set of these waves that resonate with ?2 MeV electrons, suggest that these electrons are only subject to strong scattering over a small fraction of their drift orbit. Consequently, drift-averaged scattering lifetimes are expected to lie in the range of several hours to a day. EMIC wave scattering should therefore significantly affect relativistic electron dynamics during a storm. The waves that resonate with the ˜MeV electrons are produced by low-energy (˜keV) ring current protons, which are expected to be injected into the inner magnetosphere during enhanced convection events.

Meredith, Nigel P.; Thorne, Richard M.; Horne, Richard B.; Summers, Danny; Fraser, Brian J.; Anderson, Roger R.

2003-06-01

334

Smoking cessation medications  

MedlinePLUS

Smoking cessation - medications; Smokeless tobacco - medications; Medications for stopping tobacco ... Creating a plan to help you deal with smoking urges. Getting support from a doctor, counselor, or ...

335

Medical Physiology and Experimentation: Reconsidering the Undergraduate Examination Structure  

NSDL National Science Digital Library

Discussion of how evaluation of medical physiology should be to enhance a more active participation of the students in the small-group experimentation lectures taking place during the teaching of medical physiology

Dr. Stylianos Tsakiris (University of Athens Department of Experimental Physiology Medical School); Apostolos Zarros (University of Athens Department of Experimental Physiology Medical School)

2006-06-01

336

The compact electron cyclotron resonance ion source KeiGM for the carbon ion therapy facility at Gunma University  

SciTech Connect

A high-energy carbon-ion radiotherapy facility is under construction at Gunma University Heavy Ion Medical Centre (GHMC). Its design was based on a study of the heavy ion radiotherapy at the National Institute of Radiological Sciences (NIRS) in order to reduce the size and construction cost of the facility. A compact electron cyclotron resonance ion source (ECRIS) for Gunma University, called KeiGM, was installed in 2008. It is almost a copy of the prototype ECRIS Kei2 which was developed by NIRS; meanwhile this prototype produced over 1 e mA of C{sup 4+} using C{sub 2}H{sub 2} gas (660 W and 40 kV). The beam intensity of C{sup 4+} was 600 e {mu}A with CH{sub 4} gas (250 W and 30 kV). The beam intensity satisfies the required value of 300 e {mu}A.

Muramatsu, M.; Kitagawa, A.; Drentje, A. G.; Hojo, S. [National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan); Ueda, T.; Miyazaki, H. [Sumitomo Heavy Industries, Ltd., 5-2 Soubiraki, Niihama, Ehime 792-8588 (Japan); Yusa, K.; Tashiro, M.; Torikai, K.; Sakama, M.; Kanai, T.; Yamada, S. [Gunma University, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511 (Japan)

2010-02-15

337

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

SciTech Connect

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.

Braccini, Saverio [Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics (LHEP), University of Bern, Sidlerstrasse 5, CH-3012 Bern (Switzerland)

2013-04-19

338

Medical clip  

NASA Technical Reports Server (NTRS)

An X-ray transparent and biological inert medical clip for treating aneurisms and the like is described. A graphite reinforced composite film is molded into a unitary structure having a pair of hourglass-like cavities hinged together with a pair of jaws for grasping the aneurism extending from the wall of one cavity. A silicone rubber pellet is disposed in the other cavity to exert a spring force through the hinge area to normally bias the jaws into contact with each other.

Baucom, R. M. (inventor)

1983-01-01

339

Medical Mystery  

NSDL National Science Digital Library

This activity (on pages 15-23) combines interactive role-playing and graphing to introduce learners to the health affects of pollen. In the first part, learners role-play a detective on a medical case and the main character in the case. Learners formulate a hypothesis about a patient's illness. In the second part, learners graph evidence based on pollen counts and create a "final report" about what caused the patient's health problem. This activity smoothly combines health education, environmental science, and math.

Museum, University O.; Nebraska Cooperative Extension 4-H Youth Development

2001-01-01

340

Medical Mysteries  

NSDL National Science Digital Library

Rice University presents Medical Mysteries (or MedMyst for short) "an Internet-based adventure...in which you are on a mission to discover the causes of diseases." Designed for middle and high school students, MedMyst offers an engaging, multimedia approach to learning about infectious diseases and the immune system, as well as pharmacology, chemistry, public health policy, and more. MedMyst also includes three downloadable mini-labs that expand on concepts covered in the multimedia adventure. The Web site also includes loads of useful links.

2008-05-21

341

Electron cyclotron resonance ion sources in use for heavy ion cancer therapya)  

NASA Astrophysics Data System (ADS)

The use of electron cyclotron resonance (ECR) ion sources for producing ion beams for heavy ion cancer therapy has been established for more than ten years. After the Heavy Ion Medical Accelerator (HIMAC) at Chiba, Japan started therapy of patients with carbon ions in 1994 the first carbon ion beam for patient treatment at the accelerator facility of GSI was delivered in 1997. ECR ion sources are the perfect tool for providing the required ion beams with good stability, high reliability, and easy maintenance after long operating periods. Various investigations were performed at GSI with different combinations of working gas and auxiliary gas to define the optimal beam conditions for an extended use of further ion species for the dedicated Heidelberg Ion Beam Therapy (HIT) facility installed at the Radiological University Hospital Heidelberg, Germany. Commercially available compact all permanent magnet ECR ion sources operated at 14.5GHz were chosen for this facility. Besides for C4+12 these ion sources are used to provide beams of H31+1, He1+3, and O6+16. The final commissioning at the HIT facility could be finished at the end of 2006.

Tinschert, K.; Iannucci, R.; Lang, R.

2008-02-01

342

Use of electron cyclotron resonance x-ray source for nondestructive testing application  

SciTech Connect

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.

Baskaran, R.; Selvakumaran, T.S. [Radiological Safety Division, Safety Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India)

2006-03-15

343

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

SciTech Connect

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

Winkelmann, T.; Cee, R.; Haberer, T.; Naas, B.; Peters, A.; Scheloske, S.; Spaedtke, P.; Tinschert, K. [Heidelberger Ionenstrahl-Therapie Centrum (HIT), D-69120 Heidelberg (Germany); GSI Darmstadt, D-64291 Darmstadt (Germany)

2008-02-15

344

Electron cyclotron resonance ion sources in use for heavy ion cancer therapy  

SciTech Connect

The use of electron cyclotron resonance (ECR) ion sources for producing ion beams for heavy ion cancer therapy has been established for more than ten years. After the Heavy Ion Medical Accelerator (HIMAC) at Chiba, Japan started therapy of patients with carbon ions in 1994 the first carbon ion beam for patient treatment at the accelerator facility of GSI was delivered in 1997. ECR ion sources are the perfect tool for providing the required ion beams with good stability, high reliability, and easy maintenance after long operating periods. Various investigations were performed at GSI with different combinations of working gas and auxiliary gas to define the optimal beam conditions for an extended use of further ion species for the dedicated Heidelberg Ion Beam Therapy (HIT) facility installed at the Radiological University Hospital Heidelberg, Germany. Commercially available compact all permanent magnet ECR ion sources operated at 14.5 GHz were chosen for this facility. Besides for {sup 12}C{sup 4+} these ion sources are used to provide beams of {sup 1}H{sub 3}{sup 1+}, {sup 3}He{sup 1+}, and {sup 16}O{sup 6+}. The final commissioning at the HIT facility could be finished at the end of 2006.

Tinschert, K.; Iannucci, R.; Lang, R. [Gesellschaft fuer Schwerionenforschung (GSI), Planckstrasse 1, D-64291 Darmstadt (Germany)

2008-02-15

345

Beam injection improvement for electron cyclotron resonance charge breeders  

SciTech Connect

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.

Lamy, T.; Angot, J.; Sortais, P.; Thuillier, T. [Universite Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut Polytechnique de Grenoble, Grenoble (France); Galata, A. [INFN, Laboratori Nazionali di Legnaro, Legnaro (Padova) (Italy)

2012-02-15

346

Superthermal electron distribution measurements from polarized electron cyclotron emission  

SciTech Connect

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.

Luce, T.C.; Efthimion, P.C.; Fisch, N.J.

1988-06-01

347

Characteristics of Alfvén cyclotron instabilities in thermally anisotropic plasmas  

NASA Astrophysics Data System (ADS)

Spacecraft observations in the compressed magnetosheath exhibit an inverse correlation between the proton temperature anisotropy and the parallel proton beta. Linear Vlasov theory and one-dimensional hybrid simulations suggest that the inverse correlation results from the excitation of low frequency, electromagnetic instabilities that limit the maximum value of ion temperature anisotropy for a given parallel proton beta. In this work, we examine the characteristics of such instabilities for plasma parameters typical of laboratory experiments. We find similar phenomena should occur in laboratory experiments and present experimental data consist with limited ion temperature anisotropy due to the excitation of ion cyclotron waves.

Scime, Earl; Balkey, Mathew M.; Gary, S. Peter; Keiter, Paul A.; Kline, John L.

2002-11-01

348

Cyclotron production of Ac-225 for targeted alpha therapy.  

PubMed

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

Apostolidis, C; Molinet, R; McGinley, J; Abbas, K; Möllenbeck, J; Morgenstern, A

2005-03-01

349

Initiative in Nuclear Theory at the Variable Energy Cyclotron Centre  

E-print Network

We recall the path breaking contributions of the nuclear theory group of the Variable Energy Cyclotron Centre, Kolkata. From a beginning of just one person in 1970s, the group has steadily developed into a leading group in the country today, with seminal contributions to almost the entire range of nuclear physics, viz., low energy nuclear reactions, nuclear structure, deep inelastic collisions, fission, liquid to gas phase transitions, nuclear matter, equation of state, mass formulae, neutron stars, relativistic heavy ion collisions, medium modification of hadron properties, quark gluon plasma, and cosmology of early universe.

D. K. Srivastava; J. Alam; D. N. Basu; A. K. Chaudhuri; J. N. De; K. Krishan; S. Pal

2005-06-24

350

Generating electron cyclotron resonance plasma using distributed scheme  

SciTech Connect

This study employs a distributed microwave input system and permanent magnets to generate large-area electron cyclotron resonance (ECR) plasma. ECR plasmas were generated with nitrogen gas, and the plasma density was measured by Langmuir probe. A uniform ECR plasma with the electron density fluctuation of {+-}9.8% over 500 mm Multiplication-Sign 500 mm was reported. The proposed idea of generating uniform ECR plasma can be scaled to a much larger area by using n Multiplication-Sign n microwave input array system together with well-designed permanent magnets.

Huang, C. C. [Department of Mechanical Engineering, National Taiwan University, Taipei, Taiwan (China); Chung-Shan Institute of Science and Technology, Lung-Tan, Taoyuan, Taiwan (China); Chang, T. H.; Chen, N. C.; Chao, H. W. [Department of Physics, National Tsing Hua University, Hsinchu, Taiwan (China); Chen, C. C. [Chung-Shan Institute of Science and Technology, Lung-Tan, Taoyuan, Taiwan (China); Chou, S. F. [Department of Mechanical Engineering, National Taiwan University, Taipei, Taiwan (China)

2012-08-06

351

Electromagnetic ion/ion cyclotron instability at slow shocks  

NASA Technical Reports Server (NTRS)

The linear and nonlinear properties of the obliquely propagating electromagnetic ion/ion cyclotron instability are investigated. The instability is driven by the relative, field-aligned streaming of two ion beams and can exist at a lower velocity threshold than the more commonly studied, parallel propagating electromagnetic ion beam instabilities. It is shown that the instability plays an important role in the formation of, dissipation at, and waves upstream of slow mode shocks. Possible application of this instability to ion beams in the plasma sheet boundary layer is also briefly discussed.

Winske, D.; Omidi, N.

1990-01-01

352

Thinking About Medical School?  

E-print Network

Thinking About Medical School? Explore the DO Difference! Osteopathic Medical Education Training's Osteopathic Medical Schools · Meet with Medical School Admission Officers · Learn about osteopathic medicine and medical schools · Discover the best ways to prepare for medical school When Where Pre-Health Advisor

de Lijser, Peter

353

Electron cyclotron current drive modelling with parallel momentum correction for tokamaks and stellarators  

SciTech Connect

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.

Maassberg, H.; Beidler, C. D.; Marushchenko, N. B. [Max-Planck Institut fuer Plasmaphysik, EURATOM Association, D-17491 Greifswald (Germany)

2012-10-15

354

Electron cyclotron maser based on the combination two-wave resonance  

SciTech Connect

A mechanism of a combination two-wave cyclotron interaction between an electron beam and the forward/backward components of a far-from-cutoff standing wave is analyzed. This regime can be promising for the realization of high-power continuous-wave electron cyclotron masers operating in the THz frequency range.

Savilov, A. V. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod (Russian Federation) and Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod (Russian Federation)

2012-11-01

355

Experimental and theoretical studies of a 35 GHz cyclotron autoresonance maser amplifier  

E-print Network

Experimental and theoretical studies of a 35 GHz cyclotron autoresonance maser amplifier A. C. Di maser (CARM) amplifier are reported. The measurements are carried out at a frequency of 35 GHz using agreement with the experimental observations. I. INTRODUCTION The cyclotron autoresonance maser (CARM) has

Wurtele, Jonathan

356

Theory of electron cyclotron maser interaction in a cavity at the harmonic frequencies  

Microsoft Academic Search

A theory of the cyclotron maser interaction between an annular electron beam and the standing electromagnetic wave in a cavity structure is formulated on the basis of the relativistic Vlasov equation and the Maxwell equations. Detailed analytical expressions for the beam-wave coupling coefficient, beam energy gain, and threshold beam power have been derived for the fundamental and higher cyclotron harmonics.

K. R. Chu

1978-01-01

357

Theory and observation of electromagnetic ion cyclotron triggered emissions in the magnetosphere  

E-print Network

Click Here for Full Article Theory and observation of electromagnetic ion cyclotron triggered wave growth theory of electromagnetic ion cyclotron (EMIC) triggered emissions observed in the inner agreement between the numerical solutions and the wave spectrum of the EMIC triggered emissions. Citation

Santolik, Ondrej

358

Cyclotron waves in a non-neutral plasma column Daniel H. E. Dubin  

E-print Network

-neutral plasma column with general radial density and electric field profiles. Terms in the perturbedCyclotron waves in a non-neutral plasma column Daniel H. E. Dubin Citation: Phys. Plasmas 20://pop.aip.org/authors #12;Cyclotron waves in a non-neutral plasma column Daniel H. E. Dubin Department of Physics

California at San Diego, University of

359

Determining ion production rates near Saturn's extended neutral cloud from ion cyclotron wave amplitudes  

Microsoft Academic Search

Recent Cassini observations of active venting of water molecules from Enceladus indicate that the moon is the primary source of Saturn's extended neutral cloud. Ionization of the neutrals through charge exchange creates a population of newborn ions with a velocity space distribution, which is highly unstable to the generation of electromagnetic ion cyclotron waves. Cassini observed such ion cyclotron waves,

M. M. Cowee; N. Omidi; C. T. Russell; X. Blanco-Cano; R. L. Tokar

2009-01-01

360

Electrostatic electron cyclotron waves generated by low-energy electron beams  

E-print Network

Electrostatic electron cyclotron waves generated by low-energy electron beams J. D. Menietti, O; KEYWORDS: electrostatic electron waves, plasma waves, beam mode Citation: Menietti, J. D., O. Santolik, J. D. Scudder, J. S. Pickett, and D. A. Gurnett, Electrostatic electron cyclotron waves generated

Santolik, Ondrej

361

Ion-cyclotron turbulence and diagonal double layers in a magnetospheric plasma  

NASA Technical Reports Server (NTRS)

A survey of current concepts regarding electrostatic ion-cyclotron turbulence (theory and experiment), and regarding inclined double potential layers in the magnetospheric plasma is presented. Anomalous resistance governed by electrostatic ion-cyclotron turbulence, and one-dimensional and two-dimensional models of double electrostatic layers in the magnetospheric plasma are examined.

Liperovskiy, V. A.; Pudovkin, M. I.; Skuridin, G. A.; Shalimov, S. L.

1981-01-01

362

Study of the low-frequency ion-cyclotron turbulence in a cylindrical plasma magnetically confined  

Microsoft Academic Search

A cylindrical column of magnetized plasma is produced by means of the hot cathode laboratory device MISTRAL using various gases (Neon, Argon, Krypton). In usual experimental conditions, strongly nonlinear low frequency instabilities in the ion cyclotron range are recorded. A transition towards ion cyclotron turbulence appears to be triggered by a threshold value of the radial electric field. In order

Steve Jaeger; Abdelilah Ajendouz; Cedric Brault; Amine Erradi; Thiery Pierre; Alexandre Escarguel; Cyril Rebont; Nicolas Claire; Eric Faudot; Stephane Heuraux; Kamal Quotb

2007-01-01

363

Quantum non demolition measurement of cyclotron excitations in a Penning trap  

NASA Technical Reports Server (NTRS)

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.

Marzoli, Irene; Tombesi, Paolo

1993-01-01

364

Medical Marketing Semi MedicalMarketingSemi  

E-print Network

U.S. ARMY Medical Marketing Semi WELCOME U.S.ARMY MedicalMarketingSemi Virginia Tech DATE: 23 October 2014 TIME: 8:00 am - 8:00 pm LOCATION: On Campus The Medical Marketing Semi is an operationally flexible, mobile medical exhibit. The MMS has various peripheral multi-media systems and displays

Buehrer, R. Michael

365

Acquisition of medical device start-ups  

E-print Network

Introduction: In the medical device space, a large proportion of the breakthrough inventions are developed by small firms that use private equity to bring their technologies from concept to varying stages of development. ...

Nair, Ganesh R

2006-01-01

366

Precision assembly systems for medical devices  

Microsoft Academic Search

Purpose – The purpose of this paper is to describe the approach and technology of various companies making automated assembly equipment for medical devices. Design\\/methodology\\/approach – The structure of the medical device assembly market is introduced, and the expertise and applications of a small company working in the intermediate production market is described. The modular approach of Mikron Assembly Technology

Christine Connolly

2009-01-01

367

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

NASA Technical Reports Server (NTRS)

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.

Vlahos, Loukas; Sprangle, Phillip

1987-01-01

368

Mass Measurements with the CSS2 and CIME cyclotrons at GANIL  

SciTech Connect

This paper presents two original direct mass-measurement techniques developed at GANIL using the CSS2 and CIME cyclotrons as high-resolution mass spectrometers. The mass measurement with the CSS2 cyclotron is based on a time-of-flight method along the spiral trajectory of the ions inside the cyclotron. The atomic mass excesses of 68Se and 80Y recently measured with this technique are -53.958(246) MeV and -60.971(180) MeV, respectively. The new mass-measurement technique with the CIME cyclotron is based on the sweep of the acceleration radio-frequency of the cyclotron. Tests with stable beams have been performed in order to study the accuracy of this new mass-measurement method and to understand the systematic errors.

Gomez Hornillos, M. B.; Chartier, M.; Demonchy, C. E. [University of Liverpool, Oliver Lodge Laboratory, L69 7ZE Liverpool (United Kingdom); Mittig, W.; Chautard, F.; Georgiev, G.; Jacquot, B.; Jurado, B.; Lecesne, N.; Rousseau, M.; Roussel-Chomaz, P.; Savajols, H.; Villari, A. C. C. [GANIL, Bld Henri Becquerel, BP 5027, 14076 Caen Cedex 5 (France); Blank, B. [CEN Bordeaux-Gradignan, Le Haut-Vigneau, 33175 Gradignan (France); Caballero, L. [IFIC, CSIC-Universidad de Valencia, E-46071 Valencia (Spain); Gillibert, A. [CEA/DSM/DAPNIA/SPhN, CEN Saclay, 91191 Gif-sur-Yvette (France); Lepine-Szily, A. [IFUSP, Caixa Postal 66318, CEP 05315-970 Sao Paulo (Brazil); Orr, N. [LPC, 6 Bld du Marechal Juin, 14050 Caen Cedex (France); Politi, G. [Universita di Catania, 64 Via S. Sofia, 95123 Catania (Italy)

2006-03-13

369

Simulation of the direct production of 99mTc at a small cyclotron  

NASA Astrophysics Data System (ADS)

Usually 99mTc is produced indirectly through generator 99Mo/99mTc. In the present study, the direct production of this radioisotope by charged particle irradiation was investigated using Monte Carlo method. After scouting of the reactions that produce 99mTc, excitation functions of these reactions were predicted by optical model components in the TALYS-1.6 code. Suitable energy range of projectile for this production was selected by spotting of maximum cross section and minimum impurity due to other emission channels. Then target geometry was designed based on stopping power calculation by the SRIM code. Thick target yield of 100Mo(p,2n)99mTc, 98Mo(p,?)99mTc and natMo(p,x)99mTc reactions was predicted by the result of excitation function and stopping power calculations. Finally, 100Mo(p,2n)99mTc reaction was selected as a primary reaction for the direct production of 99mTc and its process was simulated by employing the MCNPX code to calculate the energy distribution of proton in the 100Mo target body and estimation of residual nuclei during irradiation. Good agreement was obtained between the experimental, the theoretical, and the simulation-based (analytical and directly) production yields. This study demonstrated that Monte Carlo provides a method for the design and optimization of targets for the radionuclide production purposes.

Eslami, M.; Kakavand, T.

2014-06-01

370

Theory of the anomalous Doppler cyclotron-resonance-maser amplifier with tapered parameters G. S. Nusinovich,1  

E-print Network

Theory of the anomalous Doppler cyclotron-resonance-maser amplifier with tapered parameters G. S The theory of a slow-wave cyclotron-resonance-maser CRM amplifier employing an initially linear elec- tron Cyclotron resonance masers CRM's are sources of co- herent electromagnetic EM radiation based on the cyclo

Jerby, Eli

371

77 FR 31143 - Emergency Medical Services Week, 2012  

Federal Register 2010, 2011, 2012, 2013, 2014

...Proclamation 8824--Emergency Medical Services Week, 2012 Proclamation 8825--National Safe Boating Week, 2012 Proclamation 8826--National Small Business Week, 2012 Proclamation 8827--World Trade Week, 2012...

2012-05-24

372

Small Bowel Transplant  

PubMed Central

EXECUTIVE SUMMARY Objective The Medical Advisory Secretariat undertook a review of the evidence on the effectiveness and cost-effectiveness of small bowel transplant in the treatment of intestinal failure. Small Bowel Transplantation Intestinal failure is the loss of absorptive capacity of the small intestine that results in an inability to meet the nutrient and fluid requirements of the body via the enteral route. Patients with intestinal failure usually receive nutrients intravenously, a procedure known as parenteral nutrition. However, long-term parenteral nutrition is associated with complications including liver failure and loss of venous access due to recurrent infections. Small bowel transplant is the transplantation of a cadaveric intestinal allograft for the purpose of restoring intestinal function in patients with irreversible intestinal failure. The transplant may involve the small intestine alone (isolated small bowel ISB), the small intestine and the liver (SB-L) when there is irreversible liver failure, or multiple organs including the small bowel (multivisceral MV or cluster). Although living related donor transplant is being investigated at a limited number of centres, cadaveric donors have been used in most small bowel transplants. The actual transplant procedure takes approximately 12-18 hours. After intestinal transplant, the patient is generally placed on prophylactic antibiotic medication and immunosuppressive regimen that, in the majority of cases, would include tacrolimus, corticosteroids and an induction agent. Close monitoring for infection and rejection are essential for early treatment. Medical Advisory Secretariat Review The Medical Advisory Secretariat undertook a review of 35 reports from 9 case series and 1 international registry. Sample size of the individual studies ranged from 9 to 155. As of May 2001, 651 patients had received small bowel transplant procedures worldwide. According to information from the Canadian Organ Replacement Register, a total of 27 small bowel transplants were performed in Canada from 1988 to 2002. Patient Outcomes The experience in small bowel transplant is still limited. International data showed that during the last decade, patient survival and graft survival rates from SBT have improved, mainly because of improved immunosuppression therapy and earlier detection and treatment of infection and rejection. The Intestinal Transplant Registry reported 1-year actuarial patient survival rates of 69% for isolated small bowel transplant, 66% for small bowel-liver transplant, and 63% for multivisceral transplant, and a graft survival rate of 55% for ISB and 63% for SB-L and MV. The range of 1-year patient survival rates reported ranged from 33%-87%. Reported 1-year graft survival rates ranged from 46-71%. Regression analysis performed by the International Transplant Registry in 1997 indicated that centres that have performed at least 10 small bowel transplants had better patient and graft survival rates than centres that performed less than 10 transplants. However, analysis of the data up to May 2001 suggests that the critical mass of 10 transplants no longer holds true for transplants after 1995, and that good results can be achieved at any multiorgan transplant program with moderate patient volumes. The largest Centre reported an overall 1-year patient and graft survival rate of 72% and 64% respectively, and 5-year patient and graft survival of 48% and 40% respectively. The overall 1-year patient survival rate reported for Ontario pediatric small bowel transplants was 61% with the highest survival rate of 83% for ISB. The majority (70% or higher) of surviving small bowel transplant recipients was able to wean from parenteral nutrition and meet all caloric needs enterally. Some may need enteral or parenteral supplementation during periods of illness. Growth and weight gain in children after ISB were reported by two studies while two other studies reported a decrease in growth velocity with no catch-up growth. The quality of life after SBT was reported to be comparable t

2003-01-01

373

Vacuum system of the cyclotrons in VECC, Kolkata  

SciTech Connect

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)

Roy, Anindya; Bhole, R.B.; Akhtar, J.; Yadav, R.C.; Pal, Sarbajit; Sarkar, D.; Bhandari, R.K., E-mail: r_ani@vecc.gov.in, E-mail: rbb@vecc.gov.in, E-mail: javed@vecc.gov.in, E-mail: yadav@vecc.gov.in, E-mail: sarbajit@vecc.gov.in, E-mail: dsarkar@vecc.gov.in, E-mail: bhandari@vecc.gov.in [Variable Energy Cyclotron Centre, Kolkata (India)

2011-07-01

374

Electron cyclotron emission measurements on the Texas Experimental Tokamak  

SciTech Connect

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.

Austin, M.E. Jr.

1992-01-01

375

SUPERCONDUCTING RING CYCLOTRON FOR RIKEN RI BEAM FACTORY IN JAPAN  

SciTech Connect

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.

Okuno, H.; Dantsuka, T.; Yamada, K.; Kase, M.; Maie, T.; Kamigaito, O. [RIKEN Nishina Center, Wako, Saitama, 351-0198 (Japan)

2010-04-09

376

Thermal Cyclotron Absorption Coefficients. II. Opacities in the Stokes Formalism  

NASA Astrophysics Data System (ADS)

We extend the discussion of the calculation of the cyclotron opacities ?± of the ordinary and extraordinary mode (Chanmugam et al.) to the opacities ?, q, ? in the Stokes formalism. We derive formulae with which a can be calculated from ?, q, ?. We are hence able to compare our calculations of the opacities, which are based on the single-particle method, with results obtained with the dielectric tensor method of Tam or. Excellent agreement is achieved. We present extensive tables of the opacities in the Stokes formalism for frequencies up to 25?c, where ?c is the cyclotron frequency, and temperatures kT = 5, 10,20, 30,40, and 50 keV. Furthermore, we derive approximate formulae with which ?, q, ? can be calculated from ?± and hence use the Robinson & Melrose analytic formulae for ?± in order to calculate the opacities in the Stokes formalism. We compare these opacities to accurate numerical opacities and find that the analytic formulae can reproduce the qualitative behavior of the opacities in the regions where the harmonic structure is unimportant.

Vaeth, H. M.; Chanmugam, G.

1995-05-01

377

Spiral design and beam dynamics for a variable energy cyclotron  

SciTech Connect

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

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

1981-01-01

378

Recent observations of electromagnetic ion cyclotron waves in space  

NASA Astrophysics Data System (ADS)

In the past ten years observations of electromagnetic ion cyclotron (EMIC) waves in space have been reported which have greatly increased our understanding of the occurrence distribution and dynamics of Pc 1 waves in the magnetosphere. The most prominent site of EMIC wave activity is now known to be the dayside outer magnetosphere. Transient compressions of the magnetosphere have been shown to be effective in stimulating proton cyclotron wave activity by enhancing the proton temperature anisotropy. New Poynting flux measurements from Viking and IRM both indicate that wave energy is directed toward the ionosphere, in agreement with earlier ATS-6 results. Observations from lower altitude have revealed properties of lower L pulsations that reflect behavior consistent with Pc 1 pearl pulsations including quasi-periodic packets, dispersion, and occurrence in a narrow L range but wide longitudinal extent. Finally, the response of thermal ions to EMIC waves has also been studied showing that He^+ responds by developing X-type distributions indicative of non-local heating at locations along the field line where the wave frequency approaches the He^+ gyrofrequency. Further progress is likely in a number of areas: new spacecraft data sets, especially Freja; ground-satellite correlation studies; detailed instability analysis of proton distributions in the source region; and analysis of wave characteristics to assess the wave vector orientation.

Anderson, B. J.

379

Plasma-Sheath Instability in Hall Thrusters Due to Periodic Modulation of the Energy of Secondary Electrons in Cyclotron Motion  

SciTech Connect

Particle-in-cell simulation of Hall thruster plasmas reveals a plasma-sheath instability manifesting itself as a rearrangement of the plasma sheath near the thruster channel walls accompanied by a sudden change of many discharge parameters. The instability develops when the sheath current as a function of the sheath voltage is in the negative conductivity regime. The major part of the sheath current is produced by beams of secondary electrons counter-streaming between the walls. The negative conductivity is the result of nonlinear dependence of beam-induced secondary electron emission on the plasma potential. The intensity of such emission is defined by the beam energy. The energy of the beam in crossed axial electric and radial magnetic fields is a quasi-periodical function of the phase of cyclotron rotation, which depends on the radial profile of the potential and the thruster channel width. There is a discrete set of stability intervals determined by the final phase of the cyclotron rotation of secondary electrons. As a result, a small variation of the thruster channel width may result in abrupt changes of plasma parameters if the plasma state jumps from one stability interval to another.

D. Sydorenko and A. Smolyakov I. Kaganovich and Y. Raitses

2008-04-23

380

Plasma-sheath instability in Hall thrusters due to periodic modulation of the energy of secondary electrons in cyclotron motion  

SciTech Connect

Particle-in-cell simulation of Hall thruster plasmas reveals a plasma-sheath instability manifesting itself as a rearrangement of the plasma sheath near the thruster channel walls accompanied by a sudden change of many discharge parameters. The instability develops when the sheath current as a function of the sheath voltage is in the negative conductivity regime. The major part of the sheath current is produced by beams of secondary electrons counter-streaming between the walls. The negative conductivity is the result of nonlinear dependence of beam-induced secondary electron emission on the plasma potential. The intensity of such emission is defined by the beam energy. The energy of the beam in crossed axial electric and radial magnetic fields is a quasiperiodical function of the phase of cyclotron rotation, which depends on the radial profile of the potential and the thruster channel width. There is a discrete set of stability intervals determined by the final phase of the cyclotron rotation of secondary electrons. As a result, a small variation of the thruster channel width may result in abrupt changes of plasma parameters if the plasma state jumps from one stability interval to another.

Sydorenko, D.; Smolyakov, A. [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2 (Canada); Kaganovich, I.; Raitses, Y. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

2008-05-15

381

Medical muddle.  

PubMed

Nanette Gartrell, MD, is a psychiatrist and researcher whose investigations have documented the mental health and psychological well-being of lesbian, gay, bisexual, and transgender (LGBT) people over the past four decades. Nanette is the principal investigator of an ongoing longitudinal study of lesbian families in which the children were conceived by donor insemination. Now in its 27th year, this project has been cited internationally in the debates over equality in marriage, foster care, and adoption. Previously on the faculty at Harvard Medical School and the University of California, San Francisco, Nanette is currently a Visiting Distinguished Scholar at the Williams Institute, UCLA School of Law. In 2013, Nanette received the Association of Women Psychiatrists Presidential Commendation Award for "selfless and enduring vision, leadership, wisdom, and mentorship in the fields of women's mental health, ethics, and gender research." At the age of 63, Nanette experienced a 3 ½ month period of intractable, incapacitating dizziness for which there was never a clear diagnosis. PMID:24400630

Gartrell, Nanette

2014-01-01

382

Medical education: progress and retreat.  

PubMed

In summary, there have been significant educational improvements, particularly during the first two years of medical school. Students today are more accomplished, more diverse, and there is now a focus on the highly relevant basic science of medical practice, including medical ethics and public health. The curriculum has been centralized and coordination between various departments has vastly improved as a result. The number of lectures has been reduced, replaced by more effective small-group, problem-solving seminars. Support services for students have made medical school a much more enjoyable experience. On the other hand, the dramatic shift in the nature of hospitalized patients has adversely affected traditional bedside teaching that was such an important part of clinical education in the past. Extensive diagnostic evaluations now take place in an ambulatory setting. Hospitals and medical schools have not yet found a satisfactory way to integrate trainees into these venues. Finally, there has been a marked decrease in the number of graduates seeking careers in primary care, a phenomenon influenced by huge educational debts, the attraction of being able to master a defined discipline, and the desire to combine a medical life with a reasonable life-style. On balance, although the overall education of our future doctors has definitely been improved in the past fifty years, the erosion in fundamental clinical skills has been a disappointment. PMID:21073012

Gifford, Robert H

2010-10-01

383

Cyclotrons with fast variable and/or multiple energy extraction  

NASA Astrophysics Data System (ADS)

We discuss the possibility in principle of stripping extraction in combination with reverse bends in isochronous separate-sector cyclotrons (and/or fixed field alternating gradient accelerators). If one uses reverse bends between the sectors (instead of or in combination with drifts) and places stripper foils at the sector exit edges, the stripped beam has a reduced bending radius and it should be able to leave the cyclotron within the range of the valley—even if the beam is stripped at less than full energy. We are especially interested in stripping of H2+, as it doubles the charge to mass ratio of the ions. However the method could be applied to other ions or ionized molecules as well. For the production of proton beams by stripping extraction of an H2+ beam, we discuss possible designs for three types of machines: First, a low-energy cyclotron for the simultaneous production of several beams at multiple energies—for instance 15, 30, and 70 MeV—thus allowing beam delivery on several isotope production targets. In this case it can be an advantage to have a strong energy dependence of the direction of the extracted beam. Second, we consider a fast variable-energy proton machine for cancer therapy that should allow extraction (of the complete beam) at all energies in the range of about 70 MeV to about 250 MeV into the same beam line. Third, we consider a high-intensity high-energy machine, where the main design goals are extraction with low losses, low activation of components, and high reliability. Especially if such a machine is considered for an accelerator driven system (ADS), this extraction mechanism has advantages: Beam trips by the failure of electrostatic elements could be avoided and the turn separation would be less critical, which allows operation at lower main cavity voltages. This would in turn reduce the number of rf trips. The price that has to be paid for these advantages is an increase in size and/or field strength compared to proton machines with standard extraction at the final energy.

Baumgarten, C.

2013-10-01

384

Electron cyclotron emission imaging and applications in magnetic fusion energy  

NASA Astrophysics Data System (ADS)

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.

Tobias, Benjamin John

385

Technical Note: Building a combined cyclotron and MRI facility: Implications for interference  

SciTech Connect

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.

Hofman, Mark B. M.; Kuijer, Joost P. A.; Ridder, Jan Willem de; Perk, Lars R.; Verdaasdonk, Rudolf M. [Physics and Medical Technology, VU University Medical Center, Amsterdam 1007 MB (Netherlands) and BV Cyclotron VU, Amsterdam 1081HV (Netherlands)

2013-01-15

386

A review of ion sources for medical accelerators (invited)  

SciTech Connect

There are two major medical applications of ion accelerators. One is a production of short-lived isotopes for radionuclide imaging with positron emission tomography and single photon emission computer tomography. Generally, a combination of a source for negative ions (usually H- and/or D-) and a cyclotron is used; this system is well established and distributed over the world. Other important medical application is charged-particle radiotherapy, where the accelerated ion beam itself is being used for patient treatment. Two distinctly different methods are being applied: either with protons or with heavy-ions (mostly carbon ions). Proton radiotherapy for deep-seated tumors has become widespread since the 1990s. The energy and intensity are typically over 200 MeV and several 10{sup 10} pps, respectively. Cyclotrons as well as synchrotrons are utilized. The ion source for the cyclotron is generally similar to the type for production of radioisotopes. For a synchrotron, one applies a positive ion source in combination with an injector linac. Carbon ion radiotherapy awakens a worldwide interest. About 6000 cancer patients have already been treated with carbon beams from the Heavy Ion Medical Accelerator in Chiba at the National Institute of Radiological Sciences in Japan. These clinical results have clearly verified the advantages of carbon ions. Heidelberg Ion Therapy Center and Gunma University Heavy Ion Medical Center have been successfully launched. Several new facilities are under commissioning or construction. The beam energy is adjusted to the depth of tumors. It is usually between 140 and 430 MeV/u. Although the beam intensity depends on the irradiation method, it is typically several 10{sup 8} or 10{sup 9} pps. Synchrotrons are only utilized for carbon ion radiotherapy. An ECR ion source supplies multi-charged carbon ions for this requirement. Some other medical applications with ion beams attract developer's interests. For example, the several types of accelerators are under development for the boron neutron capture therapy. This treatment is conventionally demonstrated by a nuclear reactor, but it is strongly expected to replace the reactor by the accelerator. We report status of ion source for medical application and such scope for further developments.

Muramatsu, M.; Kitagawa, A. [National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan)

2012-02-15

387

Superconducting magnet for K-500 cyclotron at VECC, Kolkata  

NASA Astrophysics Data System (ADS)

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 (? and ?), 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 ?m 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 (? and ?) 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.

Saha, Subimal; Choudhury, Jayanta; Pal, Gautam; Hajra, D. P.; Dey, R.; Sur, Amitava; Bhandari, R. K.

2009-06-01

388

Electromagnetic ion/ion cyclotron instability - Theory and simulations  

NASA Technical Reports Server (NTRS)

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.

Winske, D.; Omidi, N.

1992-01-01

389

Electron Cyclotron Measurements on the Maryland Centrifugal Experiment  

NASA Astrophysics Data System (ADS)

The Maryland Centrifugal Experiment (MCX) uses supersonic rotation to stabilize dense plasmas (n˜10^14/cc) confined in an axisymmetric magnetic mirror. This rotation is generated using an axial electrode to drive large radial currents though the plasma. The MCX plasma delivers a sufficient heat flux to make the vast majority of the plasma inaccessible to electrostatic probes, making direct measurements of the electron temperature unworkable. Electron cyclotron radiation, propagating in the whistler mode has been used in past experiments to measure the axial electron temperature distribution in mirror type machines and has the advantage of working in very dense plasmas. A radiometer has been installed on MCX to measure this radiation and the axial electron temperature is being measured. Abrupt changes in the intensity of the ECE radiation are correlated with bulk plasma instabilities provide information to further diagnose these instabilities.

Reid, Remington; Young, William; Allen, Christina; Ellis, Richard; Romero-Talamas, Carlos; Hassam, Adil

2011-11-01

390

Enhanced confinement in electron cyclotron resonance ion source plasmaa)  

NASA Astrophysics Data System (ADS)

Power loss by plasma-wall interactions may become a limitation for the performance of ECR and fusion plasma devices. Based on our research to optimize the performance of electron cyclotron resonance ion source (ECRIS) devices by the use of metal-dielectric (MD) structures, the development of the method presented here, allows to significantly improve the confinement of plasma electrons and hence to reduce losses. Dedicated measurements were performed at the Frankfurt 14 GHz ECRIS using argon and helium as working gas and high temperature resistive material for the MD structures. The analyzed charge state distributions and bremsstrahlung radiation spectra (corrected for background) also clearly verify the anticipated increase in the plasma-electron density and hence demonstrate the advantage by the MD-method.

Schachter, L.; Stiebing, K. E.; Dobrescu, S.

2010-02-01

391

Electron cyclotron beam measurement system in the Large Helical Device.  

PubMed

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(19) m(-3)). This system successfully evaluated the transmitted EC beam profile and the refraction. PMID:25430387

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

2014-11-01

392

Electron-cyclotron-resonance (ECR) plasma thruster research  

NASA Technical Reports Server (NTRS)

An experimental apparatus to scientifically investigate the process of Electron-Cyclotron-Resonance (ECR) plasma acceleration has been tested. The apparatus consists of a vacuum facility, a 20 kW microwave power supply, and an argon ECR plasma thruster. Present instrumentation allows measurement of microwave input power, reflected power, propellant flow rate, and static pressure in the vacuum tank. In initial tests, an argon ECR plasma has been initiated repeatably at power levels ranging from 0.3 to 7.0 kW. The ECR plasma appears to diverge and separate from the applied magnetic field as predicted by theory. These tests suggest that the ECR plasma acceleration concept can be studied scientifically in the new apparatus.

Sercel, Joel C.

1988-01-01

393

Alternative optical concept for electron cyclotron emission imaging  

NASA Astrophysics Data System (ADS)

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.

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

394

Electromagnetic ion cyclotron waves stimulated by modest magnetospheric compressions  

NASA Astrophysics Data System (ADS)

AMPTE/CCE magnetic field and particle data are used to test the suggestion that increased hot proton temperature anisotropy resulting from convection during magnetospheric compression is responsible for the enhancement in Pc 1 emission via generation of electromagnetic ion cyclotron (EMIC) waves in the dayside outer equatorial magnetosphere. The relative increase in magnetic field is used to gauge the strength of the compression, and an image dipole model is used to estimate the motion of the plasma during compression. Proton data are used to analyze the evolution of the proton distribution and the corresponding changes in EMIC wave activity expected during the compression. It is suggested that enhancements in dynamic pressure pump the energetic proton distributions in the outer magnetosphere, driving EMIC waves. Waves are expected to be generated most readily close to the magnetopause, and transient pressure pulses may be associated with bursts of EMIC waves, which would be observed on the ground in association with ionospheric transient signatures.

Anderson, B. J.; Hamilton, D. C.

1993-07-01

395

Electromagnetic ion cyclotron waves stimulated by modest magnetospheric compressions  

NASA Technical Reports Server (NTRS)

AMPTE/CCE magnetic field and particle data are used to test the suggestion that increased hot proton temperature anisotropy resulting from convection during magnetospheric compression is responsible for the enhancement in Pc 1 emission via generation of electromagnetic ion cyclotron (EMIC) waves in the dayside outer equatorial magnetosphere. The relative increase in magnetic field is used to gauge the strength of the compression, and an image dipole model is used to estimate the motion of the plasma during compression. Proton data are used to analyze the evolution of the proton distribution and the corresponding changes in EMIC wave activity expected during the compression. It is suggested that enhancements in dynamic pressure pump the energetic proton distributions in the outer magnetosphere, driving EMIC waves. Waves are expected to be generated most readily close to the magnetopause, and transient pressure pulses may be associated with bursts of EMIC waves, which would be observed on the ground in association with ionospheric transient signatures.

Anderson, B. J.; Hamilton, D. C.

1993-01-01

396

Electromagnetic ion cyclotron waves observed in the plasma depletion layer  

NASA Astrophysics Data System (ADS)

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.

Anderson, B. J.; Fuselier, S. A.; Murr, D.

1991-11-01

397

Anomalous galvanomagnetism, cyclotron resonance, and microwave spectroscopy of topological insulators  

NASA Astrophysics Data System (ADS)

The surface quantum Hall state, magnetoelectric phenomena, and their connection to axion electrodynamics have been studied intensively for topological insulators. One of the obstacles for observing such effects comes from nonzero conductivity of the bulk. To overcome this obstacle, we propose to use an external magnetic field to suppress the conductivity of the bulk carriers. The magnetic field dependence of galvanomagnetic and electromagnetic responses of the whole system shows anomalies due to broken time-reversal symmetry of the surface quantum Hall state, which can be used for its detection. In particular, we find negative linear dc magnetoresistivity and a quadratic field dependence of the Hall angle, shifted rf cyclotron resonance, nonanalytic microwave transmission coefficient, and saturation of the Faraday rotation angle with increasing magnetic field or wave frequency.

Tkachov, G.; Hankiewicz, E. M.

2011-07-01

398

Anomalous galvanomagnetism, cyclotron resonance and microwave spectroscopy of topological insulators  

NASA Astrophysics Data System (ADS)

The surface quantum Hall state, magneto-electric phenomena and their connection to axion electrodynamics have been studied intensively for topological insulators. One of the obstacles for observing such effects comes from nonzero conductivity of the bulk. To overcome this obstacle we propose to use an external magnetic field to suppress the conductivity of the bulk carriers. The magnetic field dependence of galvanomagnetic and electromagnetic responses of the whole system shows anomalies due to broken time-reversal symmetry of the surface quantum Hall state, which can be used for its detection. In particular, we find [1] linear bulk dc magnetoresistivity and a quadratic field dependence of the Hall angle, shifted rf cyclotron resonance, nonanalytic microwave transmission coefficient and saturation of the Faraday rotation angle with increasing magnetic field or wave frequency. [4pt] [1] G. Tkachov and E. M. Hankiewicz arXiv:1011.2756 (2010)

Hankiewicz, Ewelina; Tkachov, Grigory

2011-03-01

399

Observation of the backward electrostatic ion cyclotron wave  

SciTech Connect

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.

Goree, J.; Ono, M.; Wong, K.L.

1984-12-01

400

Electron cyclotron beam measurement system in the Large Helical Devicea)  

NASA Astrophysics Data System (ADS)

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 × 1019 m-3). This system successfully evaluated the transmitted EC beam profile and the refraction.

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

2014-11-01

401

Alternative optical concept for electron cyclotron emission imaging.  

PubMed

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

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

402

Transport induced by ion cyclotron range of frequencies waves  

NASA Astrophysics Data System (ADS)

The Vlasov equation, which includes the effect of the ion cyclotron range of frequencies (ICRF) waves, can be written as the Fokker-Planck equation which describes the quasilinear transport in phase space by using the Lie-transform method. The radial transport fluxes of particle, energy and parallel momentum driven by ICRF waves in the slab geometry have been derived. The results show that the ICRF-induced radial redistributions of particle, energy and parallel momentum are driven by the inhomogeneity in energy of the equilibrium distribution function, and related to the correlation between the excursion in the real space and the excursion in energy. For the case with strong asymmetry of ky spectrum, the ICRF-induced radial transport driven by the energy inhomogeneity dominates the ICRF-induced radial transport driven by the spatial inhomogeneity.

Zhang, Debing; Xu, Yingfeng; Wang, Shaojie

2014-11-01

403

Parametric instabilities during electron cyclotron heating of tandem mirrors  

NASA Technical Reports Server (NTRS)

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.

Nicholson, D. R.

1984-01-01

404

Electron cyclotron beam measurement system in the Large Helical Device  

SciTech Connect

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.

Kamio, S., E-mail: kamio@nifs.ac.jp; Takahashi, H.; Kubo, S.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Ito, S.; Kobayashi, S.; Mizuno, Y.; Okada, K.; Osakabe, M.; Mutoh, T. [National Institute for Fusion Science, Toki 509-5292 (Japan)

2014-11-15

405

Numerical simulation of auroral magnetospheric cyclotron emission processes  

NASA Astrophysics Data System (ADS)

A variety of astrophysical radio emissions have been identified to date in association with non-uniform magnetic fields and accelerated particle streams. Numerous such sources, including planetary and stellar auroral radio emission are spectrally well defined with a high degree of extraordinary (X-mode) polarisation [1]. In particular, for the terrestrial auroral case it is now widely accepted that such emissions are generated by an electron cyclotron-maser instability driven by a horseshoe shaped electron velocity distribution [2,3]. Such distributions are formed when particles descend into the increasing magnetic field of planetary / stellar auroral magnetospheres, where conservation of the magnetic moment results in conversion of axial momentum into rotational momentum forming an electron velocity distribution having a large spread in pitch factor. Theory has shown that such distributions are unstable to cyclotron emission in the X-mode [4]. Experiments and simulations have been conducted at the University of Strathclyde investigating the electrodynamics of an electron beam subject to significant magnetic compression [5]. More recently, a background plasma of variable density has been introduced to the interaction region of the laboratory experiment and the resultant stability of the cyclotron-maser instability investigated [6]. Corroboratory simulations have been conducted using the PiC code VORPAL to investigate the cyclotron emission process in the presence of a background plasma and in the absence of radiation boundaries [7]. Simulations have investigated the spatial growth of the instability in a sheet electron beam in the presence of a background plasma whose density increases along the path of beam propagation. These simulations demonstrate a significant enhancement in spatial growth over the larger cross-sectional dimension of the sheet beam, and can simulate the upward refraction of the generated radiation - consistent with theoretical predictions and geophysical observations of enhanced emission / growth of terrestrial AKR tangential to the auroral cavity boundary and upward refraction of the resultant radiation due to the increasing background plasma density with decreasing altitude [8]. [1] R. Bingham, R.A. Cairns and B.J. Kellett, Astron. Astrophys., 370, 1000 (2001). [2] R.E. Ergun, C.W. Carlson, C.W. McFadden et al., Astrophys. J., 538, 456 (2000). [3] I. Vorgul, R.A. Cairns and R. Bingham, Phys. Plasmas 12, 122903 (2005). [4] R.A. Cairns, I. Vorgul, R. Bingham et al., Phys. Plasmas 18, 022902 (2011). [5] K. Ronald, D.C. Speirs, S.L. McConville, et al., Phys. Plasmas, 15, 056503 (2008). [6] S.L. McConville, M.E. Koepke, K.M. Gillespie et al., Plasma Phys. Control. Fusion, 53, 124020 (2011). [7] D.C. Speirs, K. Ronald, S.L. McConville, Phys. Plasmas, 17, 056501 (2010). [8] J.D. Menietti, R.L. Mutel, I.W. Christopher et al., J. Geophys. Res., 116, A12219 (2011).

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

2012-04-01

406

Pulsed magnetic field-electron cyclotron resonance ion source operation  

SciTech Connect

The pulsed magnetic field (PuMa)-electron cyclotron resonance (ECR) ion source uses a pulsed coil to improve the peak current by opening the magnetic bottle along the beam axis. After demonstration of the principle of the pulsed magnetic extraction, the ion source was tested with different gases. We received promising results from helium to krypton. The influence of the current in the pulsed coil on the analyzed ion current was measured. With increased current levels within the pulsed coil not only the pulse height of the PuMa pulse, but the pulse length can also be controlled. By using the pulsed coil the maximum of the charge state distribution can be shifted to higher charge states. {copyright} {ital 1996 American Institute of Physics.}

Muehle, C.; Ratzinger, U.; Joest, G.; Leible, K.; Schennach, S.; Wolf, B.H. [Gesellschaft fuer Schwerionenforschung, Postfach 11 05 52, 64220 Darmstadt (Germany)] [Gesellschaft fuer Schwerionenforschung, Postfach 11 05 52, 64220 Darmstadt (Germany)

1996-03-01

407

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

SciTech Connect

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.

Tabacaru, G.; May, D. P.; Chubarian, G.; Clark, H.; Kim, G. J.; Tribble, R. E. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843-3366 (United States); Arje, J. [Accelerator Laboratory, University of Jyvaeskylae, Jyvaeskylae (Finland)

2012-02-15

408

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

SciTech Connect

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

Tabacaru, G.; May, D. P.; Chubarian, G.; Clark, H.; Kim, G. J.; Tribble, R. E. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843-3366 (United States); Arje, J. [Accelerator Laboratory, University of Jyvaeskylae, Jyvaeskylae (Finland)

2013-04-19

409

Particle diagnostics of ion cyclotron resonance plasma heating in the Globus-M tokamak  

SciTech Connect

Basic experimental results on cyclotron heating of the ion plasma component in the Globus-M spherical tokamak obtained by means of the ACORD-12 charge-exchange ion analyzer are presented. A procedure for determining the maximum energy of fast ions confined in the plasma is described. The procedure was applied to estimate the limiting energy of hydrogen minority ions accelerated during ion cyclotron heating in the Globus-M tokamak. The experimental evaluation of the maximum hydrogen ion energy is confirmed by simulations of ion orbits. Recommendations for optimizing experiments on ion cyclotron heating in the Globus-M tokamak are formulated.

Chernyshev, F. V.; Ayushin, B. B.; Gusev, V. K.; D'yachenko, V. V.; Minaev, V. B.; Mironov, M. I.; Petrov, M. P.; Petrov, Yu. V.; Sakharov, N. V.; Khitrov, S. A.; Shcherbinin, O. N. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)

2009-11-15

410

Experiments on ion cyclotron damping at the deuterium fourth harmonic in DIII-D  

SciTech Connect

Absorption of fast Alfven waves by the energetic ions of an injected beam is evaluated in the DIII-D tokamak. Ion cyclotron resonance absorption at the fourth harmonic of the deuteron cyclotron frequency is observed with deuterium neutral beam injection (f = 60 MHz, B{sub T} = 1.9 T). Enhanced D-D neutron rates are evidence of absorption at the Doppler-shifted cyclotron resonance. Characteristics of global energy confinement provide further proof of substantial beam acceleration by the rf. In many cases, the accelerated deuterons cause temporary stabilization of the sawtooth (monster sawteeth), at relatively low rf power levels of {approximately}1 MW.

Pinsker, R.I.; Petty, C.C. [General Atomics, San Diego, CA (United States); Baity, F.W. [Oak Ridge National Lab., TN (United States); Bernabei, S.; Greenough, N. [Princeton Plasma Physics Lab., NJ (United States); Heidbrink, W.W. [Univ. of California, Irvine, CA (United States); Mau, T.K. [Univ. of California, San Diego, CA (United States); Porkolab, M. [Massachusetts Inst. of Tech., Cambridge, MA (United States)

1999-05-01

411

Gastric-fluid-utilizing micro battery for micro medical devices  

Microsoft Academic Search

A variety of micro medical devices have been developed to provide more advanced and less invasive medical treatment. An effective power supply is crucial to the operation of these devices. Currently, two types of power supply are used: small batteries or radio-power transmission. However, the former limits the operating time of the devices, while radio-power transmission affects other medical devices

Hikaru Jimbo; Norihisa Miki

2008-01-01

412

Small intestine  

NSDL National Science Digital Library

Smaller food particles move from the stomach to the small intestine. The small intestine is a long tube (like a garden hose), located just below the stomach. Most absorption of nutrients takes place in the small intestine (see absorption illustration). Keep in mind that the intestines are coiled like a snake inside of our bodies and are many feet long.

Katie Hale (CSUF; )

2006-08-18

413

Federal Medication Terminologies  

Cancer.gov

The Federal Medication (FedMed) interagency collaboration is organizing an agreed set of standard, comprehensive, freely and easily accessible Federal Medication Terminologies (FMT) to improve the exchange and public availability of medication information.

414

Medical Device Reliability BIOMATERIALS  

E-print Network

-generation packaging, where conformal coatings will serve as the primary interface between the deviceMedical Device Reliability BIOMATERIALS Our goal is to provide medical device manufacturers, and consistency of active implantable medical devices. These devices, including pacemakers, cardiac defibrillators

415

Biomedical Ethics & Medical Humanities  

E-print Network

BEMH Biomedical Ethics & Medical Humanities Scholarly Concentration Stanford University School? The Biomedical Ethics and Medical Humanities Scholarly Concentration is part of the new initiative at Stanford interactions, neonatology, issues of limited resources, ethics of medical advances, informed consent issues

Ford, James

416

Glaucoma Medical Updates  

MedlinePLUS

... Change Get Involved Research Grants Special Events Glaucoma Medical Updates Latest Medical News Updates From the Outside Looking In: Sophisticated ... Informed Sign up to receive the most recent medical and research updates . Further Information The most recent ...

417

Teaching Medical Ethics to Medical Students.  

ERIC Educational Resources Information Center

The evolution and goals of teaching medical ethics, the nature of medical ethics, and integrating such teaching into the curriculum are examined. Because moral considerations are as much a part of medical decisions as technical considerations, teaching is best done in the context of real cases. (Author/MLW)

Loewy, Erich H.

1986-01-01

418

Amplitudes of electron cyclotron waves transmitted in the ionosphere  

NASA Astrophysics Data System (ADS)

During the two-point sounding rocket experiment Observations of Electric-field Distributions in the Ionospheric Plasma-A Unique Strategy-C (OEDIPUS-C, hereinafter OC), Bernstein or electron cyclotron waves (ECWs) were transmitted over magnetic field-aligned emitter-receiver separations of hundreds of meters. Signals were observed at harmonic frequencies mfc of the electron cyclotron frequency fc, where m was 2, 3, and 4, fc ? 1.3 MHz, and the electron plasma frequency was less than half of fc. The electric fields at 2fc radiated by the emitting dipoles have been computed from the inhomogeneous Helmholtz wave equation. Using the full hot plasma theory to evaluate the dielectric tensor, a Green's function has been derived, based partly on numerical inversion and facilitated by some simplifications made possible by the given frequency and plasma parameters. Under the assumption of straight-line rays, it is found that the computed absolute voltage levels induced on the receiving dipoles are of the same order of magnitude as the observed levels. The electric field E radiation patterns at 2fc are found to be highly elongated along the direction of the Earth's magnetic induction field B. The component of E perpendicular to B, the radial or ? component, is much stronger than the other two components in a cylindrical coordinate system. The prediction of strong radial E magnitudes along ray directions very close to B is consistent with the OC observations. These results enlarge our appreciation of distinct characteristics of ECW radiation and propagation that may improve understanding of the role of these electrostatic waves in ionospheric dynamics.

James, H. G.

2011-07-01

419

Bursts in Electron Cyclotron Emission During ELMs and EHOs in Tokamaks  

NASA Astrophysics Data System (ADS)

Electron cyclotron emission (ECE) bursts during edge localized modes (ELMs) have been observed and reported in several tokamaks. A number of possible explanations have been suggested, but none describe completely the observed ECE bursts. A key to understanding these bursts is that they always occur during edge MHD activity such as ELMs or EHOs in QH-mode plasmas. Other observed properties are that the ECE bursts appear on the low-field-side with an intensity of several tens or hundreds times the thermal emission level, and with a bandwidth as narrow as the instrumental filter spacing of 400 MHz or narrower. A model based on the basic emission and absorption relationship of ECE in plasma is put forth. We calculate the radiation temperature for different electron velocity distribution functions, but with a small variable resonance frequency within the instrumental bandwidth. The resulting radiation temperature and its spectral width agree well with experimental observations both in non-Maxwellian and Maxwellian distribution, but the radiation temperature in non-Maxwellian case is much higher.

Li, E.; Austin, M. E.

2012-10-01

420

The interplay of Kappa and core populations in the solar wind: Electromagnetic electron cyclotron instability  

NASA Astrophysics Data System (ADS)

Recently, a realistic parameterization was proposed for the kinetic anisotropy and the resulting instabilities in the solar wind plasma. This parameterization is based on observations of the particle velocity distribution, which always comprises a Maxwellian population at low energies, viz. the core, and a suprathermal halo in the tail of the distribution which is best described by the Kappa (power law) models. The cyclotron instability, driven by an anisotropic electron halo, was found to be inhibited by the finite thermal spread in the core, and this effect is highly dependent on the halo-core relative density. In this paper, the interplay between the Kappa and Maxwellian populations is further investigated for more complex (less idealized) situations when both the core and halo temperatures are anisotropic. Growth of this instability is markedly stimulated by the core anisotropy. The wave numbers that are stable for an isotropic core become unstable even for small anisotropies of this population. Just a modest increase of the core anisotropy from Ac=T?/T?=1.2 to 2 causes the growth rates to enhance by 1 order of magnitude, and the range of unstable wave numbers to extend considerably. When the anisotropies in the core and halo are comparable, the growth rate exhibits two distinct peaks, the first driven by the halo at lower wave numbers and the second driven by the core. However, the first peak is inhibited by the suprathermal populations, while the second peak is sustained, suggesting a more intricate connection between the core and Kappa populations.

Lazar, M.; Poedts, S.; Schlickeiser, R.

2014-12-01

421

Local and global properties of plasma waves at the proton cyclotron frequency upstream from Mars  

NASA Astrophysics Data System (ADS)

A comprehensive study on the properties of electromagnetic ULF plasma waves upstream from Mars is presented. This study is based on reliable upstream measurements provided by the magnetometer and electron reflectometer (MAG/ER) onboard the Mars Global Surveyor (MGS) spacecraft during the Science Phasing Orbit period. We find that a large majority of these waves is characterized - in the spacecraft frame - by a left-hand circular polarization and a frequency which coincides with the local proton cyclotron frequency. Minimum variance analysis of the magnetic field indicates that these waves propagate almost parallel to the background magnetic field and comparison with suprathermal electron fluxes measured by ER suggests a small degree of compressibility. A survey based on more than 300 MGS elliptical orbits indicates that these waves are almost permanent and their spatial distribution does not seem to depend on the orientation of the solar wind convective electric field assuming a flow along the Sun-Mars line. Also, we find that their amplitude decreases with radial distance from the planet, supporting the idea that their source is Mars. Theoretical (analytical and numerical) approaches suggest that these properties are compatible with plasma waves originating in the pick-up of ionized exospheric hydrogen. We discuss these theoretical results and their implications for Mars and other atmospheric unmagnetized objects such as Venus.

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

2011-12-01

422

Electron cyclotron resonance deposition of amorphous silicon alloy films and devices  

SciTech Connect

This report describes work to develop a state-of-the-art electron cyclotron resonance (ECR) plasma-enhanced chemical vapor deposition (PECVD) system. The objective was to understand the deposition processes of amorphous silicon (a-Si:H) and related alloys, with a best-effort improvement of optoelectronic material properties and best-effort stabilization of solar cell performance. ECR growth parameters were systematically and extensively investigated; materials characterization included constant photocurrent measurement (CPM), junction capacitance, drive-level capacitance profiling (DLCP), optical transmission, light and dark photoconductivity, and small-angle X-ray scattering (SAXS). Conventional ECR-deposited a-Si:H was compared to a new form, a-Si:(Xe, H), in which xenon gas was added to the ECR plasma. a-Si:(Xe,H) possessed low, stable dark conductivities and high photosensitivites. Light-soaking revealed photodegradation rates about 35% lower than those of comparable radio frequency (rf)-deposited material. ECR-deposited p-type a SiC:H and intrinsic a-Si:H films underwent evaluation as components of p-i-n solar cells with standard rf films for the remaining layers.

Shing, Y.H. (Jet Propulsion Lab., Pasadena, CA (United States))

1992-10-01

423

Proton cyclotron waves upstream from Mars: Observations from Mars Global Surveyor  

NASA Astrophysics Data System (ADS)

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 frequency of these waves, measured in the MGS reference frame (SC), is 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 the increase of the interplanetary magnetic field (IMF) cone angle and radial distance from the planet. The latter result supports the idea that the source of these waves is Mars. In addition, we find that these waves are not associated with the foreshock and their properties (ellipticity, degree of polarization, direction of propagation) do not depend on the IMF cone angle. Empirical evidence and theoretical approaches suggest that most of these observations correspond to the ion-ion right hand (RH) mode originating from the pick-up of ionized exospheric hydrogen. The left-hand (LH) mode might be present in cases where the IMF is almost perpendicular to the Solar Wind direction. PCWs occur in 62% of the time during SPO1 subphase, whereas occurrence drops to 8% during SPO2. Also, SPO1 PCWs preserve their characteristics for longer time periods and have greater degree of polarization and coherence than those in SPO2. We discuss these results in the context of possible changes in the pick-up conditions from SPO1 to SPO2, or steady, spatial inhomogeneities in the wave distribution. The lack of influence from the Solar Wind's convective electric field upon the location of PCWs indicates that, as suggested by recent theoretical results, there is no clear relation between the spatial distribution of PCWs and that of pick-up ions.

Romanelli, N.; Bertucci, C.; Gómez, D.; Mazelle, C.; Delva, M.

2013-02-01

424

The Ranger medic.  

PubMed

The Ranger medic (military occupational specialty 91B) provides advanced trauma management across the operational spectrum in which the 75th Ranger Regiment is employed. Ranger medic duties, both in combat environments and in training, medical training, professional progression, and medical assets in the Ranger battalion are detailed. Ranger medic training management tools and techniques are discussed and illustrated. The role of the combat lifesaver, force modernization, and interoperability issues facing the medical team are discussed. The Ranger medic is a capable special operations tactical medic. PMID:11370201

Pappas, C G

2001-05-01

425

Medical Student Appraisal  

PubMed Central

Background Medical students are often afforded the privilege of counselling patients. In the past resources were limited to pen and paper or anatomic models. The evolution of mobile applications allows for limitless access to resources that facilitate bedside patient education. Objectives To evaluate the utility of six applications in patient education and promote awareness of implementing mobile resources in clinical care. Methods Six medical students rotating on various clerkships evaluated a total of six mobile applications. Strengths, limitations, and suggested uses in clinical care were identified. Applications included MeditoonsTM, VisiblePatientTM, DrawMDTM, CardioTeachTM, Visual AnatomyTM, and 360° Patient Education SuiteTM. Data was generated from narrative responses supplied by each student during their evaluation period. Results Bedside teaching was enhanced by professional illustrations and animations depicting anatomy and pathophysiology. Impromptu teaching was facilitated, as resources were conveniently available on a student’s smartphone or tablet. The ability to annotate and modify images and subsequently email to patients was an extraordinary improvement in provider-patient communication. Universal limitations included small smartphone screens and the novelty of new technology. Discussion Mobile applications have the potential to greatly enhance patient education and simultaneously build rapport. Endless opportunities exist for their integration in clinical practice, particularly for new diagnoses, consent for procedures, and at time of discharge. Providers should be encouraged to try new applications and utilize them with patients. PMID:23874358

Markman, T.M.; Sampognaro, P.J.; Mitchell, S.L.; Weeks, S.R.; Khalifian, S.; Dattilo, J.R.

2013-01-01

426

Multipurpose superconducting electron cyclotron resonance ion source, the European roadmap to third-generation electron cyclotron resonance ion sources  

NASA Astrophysics Data System (ADS)

The major infrastructures of nuclear physics in Europe adopted the technology of electron cyclotron resonance (ECR) ion sources for the production of heavy-ion beams. Most of them use 14GHz electron cyclotron resonance ion sources (ECRISs), except at INFN-LNS, where an 18GHz superconducting ECRIS is in operation. In the past five years it was demonstrated, in the frame of the EU-FP5 RTD project called "Innovative ECRIS," that further enhancement of the performances requires a higher frequency (28GHz and above) and a higher magnetic field (above 2.2T) for the hexapolar field. Within the EU-FP6 a joint research activity named ISIBHI has been established to build by 2008 two different ion sources, the A-PHOENIX source at LPSC Grenoble, reported in another contribution, and the multipurpose superconducting ECRIS (MS-ECRIS), based on fully superconducting magnets, able to operate in High B mode at a frequency of 28GHz or higher. Such a development represents a significant step compared to existing devices, and an increase of typically a factor of 10 for the intensity is expected (e.g., 1emA for medium charge states of heavy ions, or hundreds of e?A of fully stripped light ions, or even 1e?A of charge states above 50+ for the heaviest species). The challenging issue is the very high level of magnetic field, never achieved by a minimum B trap magnet system; the maximum magnetic field of MS-ECRIS will be higher than 4 or 5T for the axial field and close to 2.7T for the hexapolar field. The detailed description of the MS-ECRIS project and of its major constraints will be given along with the general issues of the developments under way.

Ciavola, G.; Gammino, S.; Celona, L.; Torrisi, L.; Passarello, S.; Andó, L.; Cavenago, M.; Galatà, A.; Spaedtke, P.; Tinschert, K.; Lang, R.; Iannucci, R.; Leroy, R.; Barue, C.; Hitz, D.; Seyfert, P.; Koivisto, H.; Suominen, P.; Tarvainen, O.; Beijers, H.; Brandenburg, S.; Vanrooyen, D.; Hill, C.; Kuchler, D.; Homeyer, H.; Röhrich, J.; Schachter, L.; Dobrescu, S.

2006-03-01

427

Multipurpose superconducting electron cyclotron resonance ion source, the European roadmap to third-generation electron cyclotron resonance ion sources  

SciTech Connect

The major infrastructures of nuclear physics in Europe adopted the technology of electron cyclotron resonance (ECR) ion sources for the production of heavy-ion beams. Most of them use 14 GHz electron cyclotron resonance ion sources (ECRISs), except at INFN-LNS, where an 18 GHz superconducting ECRIS is in operation. In the past five years it was demonstrated, in the frame of the EU-FP5 RTD project called ''Innovative ECRIS,'' that further enhancement of the performances requires a higher frequency (28 GHz and above) and a higher magnetic field (above 2.2 T) for the hexapolar field. Within the EU-FP6 a joint research activity named ISIBHI has been established to build by 2008 two different ion sources, the A-PHOENIX source at LPSC Grenoble, reported in another contribution, and the multipurpose superconducting ECRIS (MS-ECRIS), based on fully superconducting magnets, able to operate in High B mode at a frequency of 28 GHz or higher. Such a development represents a significant step compared to existing devices, and an increase of typically a factor of 10 for the intensity is expected (e.g., 1 emA for medium charge states of heavy ions, or hundreds of e{mu}A of fully stripped light ions, or even 1 e{mu}A of charge states above 50{sup +} for the heaviest species). The challenging issue is the very high level of magnetic field, never achieved by a minimum B trap magnet system; the maximum magnetic field of MS-ECRIS will be higher than 4 or 5 T for the axial field and close to 2.7 T for the hexapolar field. The detailed description of the MS-ECRIS project and of its major constraints will be given along with the general issues of the developments under way.

Ciavola, G.; Gammino, S.; Celona, L.; Torrisi, L.; Passarello, S.; Ando, L.; Cavenago, M.; Galata, A.; Spaedtke, P.; Tinschert, K.; Lang, R.; Iannucci, R.; Leroy, R.; Barue, C.; Hitz, D.; Seyfert, P.; Koivisto, H.; Suominen, P.; Tarvainen, O.; Beijers, H. [Istituto Nazionale Fisica Nucleare-Laboratori Nazionali del Sud (INFN-LNS), Via S. Sofia 62, 95123 Catania (Italy) and INFN-Laboratori Nazionali di Legnaro (INFN-LNL), 35020 Legnaro (Italy); Gesellschaft fuer Schwerionenforschung mbH (GSI), 64291 Darmstadt (Germany); Grand Accelerateur National d'Ions Lourds (GANIL), 14076 Caen (France); CEA-DRFMC-SBT, 38054 Grenoble (France); Department of Physics, University of Jyvaeskylae (JYFL), 40014 Jyvaeskylae (Finland); Kernfysisch Versneller Instituut (KVI), 9747 AA Groningen (Netherlands); Svedberg Laboratory (TSL), 75121 Uppsala (Sweden); CERN AB Department, CERN CH-1211 Geneva (Switzerland); Hahn Meitner Institut Berlin GmbH (HMI), 14109 Berlin (Germany); National Institute of Physics and Nuclear Engineering (NIPNE), MG-6, Bucharest-Magurele (Romania)] (and others)

2006-03-15

428

Medical imaging.  

PubMed Central

There is now a wide choice of medical imaging to show both focal and diffuse pathologies in various organs. Conventional radiology with plain films, fluoroscopy and contrast medium have many advantages, being readily available with low-cost apparatus and a familiarity that almost leads to contempt. The use of plain films in chest disease and in trauma does not need emphasizing, yet there are still too many occasions when the answer obtainable from a plain radiograph has not been available. The film may have been mislaid, or the examination was not requested, or the radiograph had been misinterpreted. The converse is also quite common. Examinations are performed that add nothing to patient management, such as skull films when CT will in any case be requested or views of the internal auditory meatus and heal pad thickness in acromegaly, to quote some examples. Other issues are more complicated. Should the patient who clinically has gall-bladder disease have more than a plain film that shows gall-stones? If the answer is yes, then why request a plain film if sonography will in any case be required to 'exclude' other pathologies especially of the liver or pancreas? But then should cholecystography, CT or scintigraphy be added for confirmation? Quite clearly there will be individual circumstances to indicate further imaging after sonography but in the vast majority of patients little or no extra information will be added. Statistics on accuracy and specificity will, in the case of gall-bladder pathology, vary widely if adenomyomatosis is considered by some to be a cause of symptoms or if sonographic examinations 'after fatty meals' are performed. The arguments for or against routine contrast urography rather than sonography are similar but the possibility of contrast reactions and the need to limit ionizing radiation must be borne in mind. These diagnostic strategies are also being influenced by their cost and availability; purely pragmatic considerations are not infrequently the overriding factor. Non-invasive methods will be preferred, particularly sonography as it is far more acceptable by not being claustrophobic and totally free of any known untoward effects. There is another quite different but unrelated aspect. The imaging methods, apart from limited exceptions, cannot characterize tissues as benign or malignant, granulomatous or neoplastic; cytology or histology usually provides the answer. Sonography is most commonly used to locate the needle tip correctly for percutaneous sampling of tissues. Frequently sonography with fine needle aspiration cytology or biopsy is the least expensive, safest and most direct route to a definitive diagnosis. Abscesses can be similarly diagnosed but with needles or catheters through which the pus can be drained. The versatility and mobility of sonography has spawned other uses, particularly for the very ill and immobile, for the intensive therapy units and for the operating theatre, as well in endosonography. The appointment of more skilled sonographers to the National Health Service could make a substantial contribution to cost-effective management of hospital services. Just when contrast agents and angiography have become safe and are performed rapidly, they are being supplanted by scanning methods. They are now mainly used for interventional procedures or of pre-operative 'road maps' and may be required even less in the future as MRI angiography and Doppler techniques progress. MRI will almost certainly extent its role beyond the central nervous system (CNS) should the equipment become more freely available, especially to orthopaedics. Until then plain films, sonography or CT will have to suffice. Even in the CNS there are conditions where CT is more diagnostic, as in showing calculations in cerebral cysticercosis. Then, too, in most cases CT produces results comparable to MRI apart from areas close to bone, structures at the base of the brain, in the posterior fossa and in the spinal cord. Scintigraphy for pulmonary infarcts and bone metastases and in renal disease in children plays

Kreel, L.

1991-01-01

429

Initial Results of Multi-Frequency Electron Cyclotron Heating in the Levitated Dipole  

E-print Network

electromagnet via multiple-frequency electron cyclotron resonance heating (ECRH). Multiple frequency ECRH B is the incremental flux tube volume and = 5 3 is the ratio of specific heats.[1] In addition

430

Cyclotron-based nuclear science. Progress report, April 1, 1979-March 31, 1980  

SciTech Connect

Research at the cyclotron institute is summarized. These major areas are covered: nuclear structure; nuclear reactions and scattering; polarization studies; interdisciplinary nuclear science; instrumentation and systems development; and publications. (GHT)

Not Available

1980-06-01

431

Ultracompact superconducting isochronous cyclotron production of ¹³N for positron emission tomography applications  

E-print Network

Testing was performed on a data acquisition (DAQ) system that was built specifically to characterize a new ultracompact superconducting isochronous cyclotron (USIC) at MIT. A production model of Nitrogen-13 was validated ...

Fitzgerald, Shawn (Shawn Michael)

2013-01-01

432

Feasibility study for a correlation electron cyclotron emission turbulence diagnostic based on nonlinear gyrokinetic simulations  

E-print Network

This paper describes the use of nonlinear gyrokinetic simulations to assess the feasibility of a new correlation electron cyclotron emission (CECE) diagnostic that has been proposed for the Alcator C-Mod tokamak (Marmar ...

Mikkelsen, D R

433

A Separated Sector Cyclotron for the Production of High Intensity Protons  

NASA Astrophysics Data System (ADS)

The design of a separated sector cyclotron (SSC) to produce 200 microAmps of 230 MeV protons for the ORNL radioactive beam facility is presented. This work was performed to study one of the options for the driver accelerator (other options include a compact superconducting cyclotron and a linac). This paper presents a summary of the magnetic field, injection, extraction, vacuum system and RF design choices. A guiding principle was to limit the size of the cyclotron to fit inside an existing shielded room to lower the construction cost by using the existing facility. The design has emphasized the minimization of beam losses in the cyclotron, specially in the extraction process. Space charge effects must be included in the performance estimates.

Marti, F.; Blosser, H.; Johnson, D.; Lawton, D.; Vincent, J.

1997-05-01

434

Effect of radial particle diffusion on electron cyclotron current drive in the TCV tokamak  

E-print Network

, Switzerland 2 CompX, P.O. Box 2672, Del Mar, CA 92014-5672, USA In electron cyclotron heating (ECH efficiency. We shall present results showing that with a reasonable value of the diffusion coefficient

435

Radioactive Beams Using the AECR-U and the 88-Inch Cyclotron  

SciTech Connect

The high ionization efficiency of an Electron Cyclotron Resonance (ECR) ion source combined with the mass resolution of a cyclotron is ideal for the generation of some ISOL-type radioactive ion beams (RIBs). In two separate projects at the 88-Inch Cyclotron at LBNL - BEARS and the Recyclotron - we have developed techniques to efficiently ionize and accelerate beams of gaseous species of 11C (t1/2 = 20 min), 14,15O (t1/2 = 70 sec, 2 min) and 76,79Kr (t1/2 = 14,35 hours). Measurements of the ionization efficiency and hold-up times are discussed, along with issues of source contamination and poisoning encountered in running both RIBs and high-intensity stable beam experiments using the same ion source, the LBNL AECR-U. Methods used to tune clean RIBs through the Cyclotron with high efficiency are also discussed, including the use and limitations of analog beams.

McMahan, M.A.; Leitner, D.; Powell, J.; Silver, C. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States)

2005-03-15

436

Summary of EC-17: the 17th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating (Deurne, The Netherlands, 7-10 May 2012)  

NASA Astrophysics Data System (ADS)

An overview is given of the papers presented at the 17th Joint Workshop on Electron Cyclotron Emission (ECE) and Electron Cyclotron Resonance Heating (ECRH). The meeting covered all aspects of the research field ranging from theory to enabling technologies. From the workshop, advanced control by electron cyclotron heating and current drive is emerging as probably the main application of ECRH in fusion devices. Large progress is reported from various experiments on real-time control applications. At the same time ECE is developing into a multi-dimensional plasma diagnostic taking advantage of new technological developments. The resulting multi-dimensional ECE data reveal exciting new details of the complicated plasma dynamics in fusion devices.

Westerhof, E.; Austin, M. E.; Kubo, S.; Lin-Liu, Y. R.; Plaum, B.

2013-02-01

437

Dose measurements behind reduced shielding at the Texas A&M University variable energy cyclotron  

E-print Network

DOSE MEASUREMENTS BEHIND REDUCED SHIELDING AT THE TEXAS ABM UNIVERSITY VARIABLE ENERGY CYCLOTRON A Thesis by Douglas Carey Kay Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE May 1982 Major subject: Nuclear Engineering DOSE MEASUREMENTS BEHIND REDUCED SHIELDING AT THE TEXAS ASM UNIVERSITY VARIABLE ENERGY CYCLOTRON A Thesis Douglas Carey Kay Approved as to style and content by: 'rman of t ee) (Member...

Kay, Douglas Carey

2012-06-07

438

Whistler mode electron cyclotron resonance heating and emission in a magnetic mirror plasma  

SciTech Connect

An experimental investigation has been conducted in which whistler mode electron cyclotron heating (ECRH) was performed simultaneously with whistler mode electron cyclotron emission measurements on an axisymmetric magnetic mirror plasma. Results presented include theoretical and experimental studies of the early plasma startup phase, as well as experimental studies of two instability phases. These instabilities are identified as a whistler instability and a magnetohydrodynamic (MHD) flute instability. 115 figs., 8 tabs.

Booske, J.H.

1985-06-01

439

An inexpensive x-ray source based on an electron cyclotron  

NASA Astrophysics Data System (ADS)

X rays have been produced using an electron cyclotron operated at a frequency of 2.45 GHz. This cyclotron was designed such that it would operate near the relativistic detuning limit of approximately 150 keV. The design and equipment needed are simple and inexpensive. The accelerator consists of a cylindrical cavity operated in the TE111 mode. This tuned cavity is closely coupled to and powered by a magnetron from a microwave oven.

Garner, H. R.; Ohkawa, T.; Howald, A. M.; Leonard, A. W.; Peranich, L. S.; D'Aoust, J. R.

1990-02-01

440

First tests of a CW RFQ injector for the IUCF cyclotrons  

Microsoft Academic Search

A 750 keV proton injector is being installed in place of a 600 kV Cockroft-Walton high voltage terminal at the Indiana University Cyclotron Facility. The injector features a microwave ion source, a 20 keV to 750 keV CW RFQ and a quadrupole triplet to focus the beam into the 15 MeV injector cyclotron. Two solenoids and one pulsed lens are

V. P. Derenchuk; V. Anferov; D. L. Friesel; R. W. Hamm; W. P. Jones; J. Staples

2003-01-01

441

Electrostatic hydrogen cyclotron waves near one earth radius altitude in the polar magnetosphere  

Microsoft Academic Search

The wave plasma experiment onboard satellite S3-3 has detected electrostatic hydrogen cyclotron waves at altitudes near 1R\\/sub E\\/ in the Earth's polar magnetosphere. The observed wave properties are in excellent agreement with the theory theoretical dispersion relation as well as the linear instability theory for current driven ion cyclotron waves and are used to determine that the plasma is more

P. M. Kintner; M. C. Kelley; F. S. Mozer

1978-01-01

442

Simulation, design, and testing of a high power collimator for the RDS-112 cyclotron.  

PubMed

A high power [F-18] fluoride target package for the RDS-112 cyclotron has been designed, tested, and commercially deployed. The upgrade includes the CF-1000 target, a 1.3kW water target with an established commercial history on RDS-111/Eclipse cyclotrons, and a redesigned collimator with improved heat rejection capabilities. Conjugate heat transfer analyses were employed to both evaluate the existing collimator capabilities and design a suitable high current replacement. PMID:25562677

Peeples, Johanna L; Stokely, Matthew H; Poorman, Michael C; Bida, Gerald T; Wieland, Bruce W

2015-03-01

443

Multi-Species Test of Ion Cyclotron Resonance Heating at High Altitudes  

NASA Technical Reports Server (NTRS)

Observations of ion distributions and plasma waves obtained by the Dynamics Explorer 1 satellite in the high-altitude, nightside auroral zone are used to study ion energization for three ion species. A number of theoretical models have been proposed to account for the transverse heating of these ion populations. One of these, the ion cyclotron resonance heating (ICRH) mechanism, explains ion conic formation through ion cyclotron resonance with broadband electromagnetic wave turbulence in the vicinity of the characteristic ion cyclotron frequency. The cyclotron resonant heating of the ions by low-frequency electromagnetic waves is an important energy source for the transport of ions from the ionosphere to the magnetosphere. In this paper we test the applicability of the ICRH mechanism to three simultaneously heated and accelerated ion species by modelling the ion conic formation in terms of a resonant wave-particle interaction in which the ions extract energy from the portion of the broadband electromagnetic wave spectrum which includes the ion cyclotron frequency. Using a Monte Carlo technique we evaluate the ion heating produced by the electromagnetic turbulence at low frequencies and find that the wave amplitudes near the ion cyclotron frequencies are sufficient to explain the observed ion energies.

Persoon, A. M.; Peterson, W. K.; Andre, M.; Chang, T.; Gurnett, D. A.; Retterer, J. M.; Crew, G. B.

1997-01-01

444

Multi-Species Test of Ion Cyclotron Resonance Heating at High Altitudes  

NASA Technical Reports Server (NTRS)

Observations of ion distributions and plasma waves obtained by the Dynamics Explorer 1 satellite in the high-altitude, nightside auroral zone are used to study ion energization for three ion species. A number of theoretical models have been proposed to account for the transverse heating of these ion populations. One of these, the ion cyclotron resonance heating (ICRH) mechanism, explains ion conic formation through ion cyclotron resonance with broadband electromagnetic wave turbulence in the vicinity of the characteristic ion cyclotron frequency. The cyclotron resonant heating of the ions by low- frequency electromagnetic waves is an important energy source for the transport of ions from the ionosphere to the magnetosphere. In this paper we test the applicability of the ICRH mechanism to three simultaneously heated and accelerated ion species by modelling the ion conic formation in terms of a resonant wave-particle interaction in which the ions extract energy from the portion of the broadband electromagnetic wave spectrum which includes the ion cyclotron frequency. Using a Monte Carlo technique we evaluate the ion heating produced by the electromagnetic turbulence at low frequencies and find that the wave amplitudes near the ion cyclotron frequencies are sufficient to explain the observed ion energies.

Persoon, A. M.; Peterson, W. K.; Andre, M.; Chang, T.; Gurnett, D. A.; Retterer, J. M.; Crew, G. B.

1997-01-01

445

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

SciTech Connect

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

Kurashima, Satoshi, E-mail: kurashima.satoshi@jaea.go.jp; Kashiwagi, Hirotsugu; Miyawaki, Nobumasa; Yoshida, Ken-Ichi; Okumura, Susumu [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)] [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

2014-02-15

446

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

PubMed

The JAEA AVF cyclotron accelerates various kinds of high-energy ion beams for research in biotechnology and materials science. Beam intensities of an ion species of the order of 10(-9)-10(-6) ampere are often required for various experiments performed sequentially over a day. To provide ion beams with sufficient intensity and stability, an operator has to retune an ion source in a short time. However, the beam intensity downstream of the cyclotron rarely increas