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1

Cyclotron Production of Medical Radioisotopes  

SciTech Connect

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

Avila-Rodriguez, M. A.; Zarate-Morales, A.; Flores-Moreno, A. [Unidad PET/CT-Ciclotron, Facultad de Medicina, Universidad Nacional Autonoma de Mexico, Edificio de Investigacion P.B, Cd. Universitaria, Circ. Interior, C.P. 04510 Mexico D.F. (Mexico)

2010-08-04

2

BEST medical radioisotope production cyclotrons  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

3

BEST medical radioisotope production cyclotrons  

SciTech Connect

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

Sabaiduc, Vasile; Milton, Bruce; Suthanthiran, Krishnan; Johnson, Richard R. [Best Cyclotron Systems Inc., 7-8765 Ash Street, Vancouver, British Columbia, V6P 6T3 (Canada); Gelbart, W. Z. [Advanced System Designs Inc., 5295 Bear Bay Road, Garden Bay, BC, V0N 1S1 (Canada)

2013-04-19

4

Superconducting medical cyclotron  

SciTech Connect

This patent describes a superconducting cyclotron apparatus which generates a beam of high velocity particles comprising atomic particles and subparticles thereof to be directed at an object to be irradiated from spirally accelerated charged particles around a cyclotron axis which form the beam or which impinge upon a target to produce the beam. An inlet and outlet conduit means are included for supplying and removing liquified gas to and from a vessel around superconducting coils supplied by electrical leads inside the vessel which pass around spaced apart iron poles so as to generate a magnetic field between the poles when current is supplied to the coils and which function to produce the spirally accelerated charged particles with an oscillatory electrical field. The improvement described here comprises: a Joule-Thompson effect constricted capillary tube leading to a semi-circular tube adjacent to and in heat transfer relationship with both coils and the liquified gas in the vessel, with the semi-circular tube connected to an exit tube from the vessel and cyclotron.

Blosser, H.G.; Burleigh, R.J.; Blosser, G.F.; Jemison, E.B.

1987-02-03

5

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

6

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

1985-01-01

7

The present situation and the prospect of medical cyclotrons in China  

NASA Astrophysics Data System (ADS)

The paper introduces the increasing applications of cyclotrons in the field of health care and some major work carried out abroad. Its emphasis is placed on the introduction to the application status and the development process of medical cyclotrons in China. The paper has assessed possible developing trends of medical cyclotrons based on the current application demand and the technological development status.

Zhang, TianJue; Fan, MingWu; Wei, SuMin; Chen, ShengZu; Yang, Fang

2011-12-01

8

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

9

Status of the Berkeley Small Cyclotron AMS (Accelerator Mass Spectrometry) Project.  

National Technical Information Service (NTIS)

A small, low-energy cyclotron has been designed and built at Berkeley for direct detection dating of sup 14 C. The system combines the use of a negative ion source to reject sup 14 N with the high resolution of a cyclotron to reject other background ions....

K. J. Bertsche P. G. Friedman D. E. Morris R. A. Muller J. J. Welch

1987-01-01

10

An advanced PC-PLC-based SCADA system for a commercial medical cyclotron  

NASA Astrophysics Data System (ADS)

A novel SCADA system is developed for the 30 MeV H - ion commercial Medical Cyclotron (Model: Cyclone-30) operating at proton beam currents up to 850 ?A, at the National Medical Cyclotron, Sydney Australia. Cyclone-30 control system at NMC consists of two PLCs and a PC. The NMC SCADA system is based on a IBM compatible PC and FIX DMACS software package running on Windows 3.1 platform. This system is custom built for the Cyclone-30 at NMC. High-quality graphic screens are designed to suit the cyclotron at NMC keeping up to date with all the system upgrades. This system is designed to completely replace the existing man-machine interface with many new functions. This paper describes the important components of the system including system architecture and software development.

Singlachar, Ramapriyan; Mukherjee, Bhaskar

1997-02-01

11

Medical Waste Management Implications for Small Medical Facilities.  

ERIC Educational Resources Information Center

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

Byrns, George; Burke, Thomas

1992-01-01

12

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

13

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

14

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

2013-01-01

15

A small electron cyclotron resonant plasma-based neutral-flux ionizer  

Microsoft Academic Search

The design and operation of a neutral-hydrogen flux detection system is described. The central feature of the detector is an inductively driven electron cyclotron resonance heated (ECRH) discharge, which functions as the neutral-flux ionizer. The prominent features of the ionizer are its small (5×3×3 cm3) size and excitation of the ECRH mode using a 200-W, 30-MHz rf driver and static

B. L. CainS; D. N. Ruzic

1990-01-01

16

A small electron cyclotron resonant plasma-based neutral-flux ionizer  

Microsoft Academic Search

The design and operation of a neutral-hydrogen flux detection system is described. The central feature of the detector is an inductively driven electron cyclotron resonance heated (ECRH) discharge, which functions as the neutral-flux ionizer. The prominent features of the ionizer are its small (5Ã3Ã3 cm³) size and excitation of the ECRH mode using a 200-W, 30-MHz rf driver and static

B. L. Cain; D. N. Ruzic

1990-01-01

17

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

18

Selected Reference Aids for Small Medical Libraries *  

PubMed Central

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

Duncan, Howertine Farrell

1970-01-01

19

Reclassification in a small decentralized medical library.  

PubMed Central

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

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

1977-01-01

20

Basic Reference Aids for Small Medical Libraries *  

PubMed Central

Selected primarily for the small medical library, this list is compiled to serve as a practical guide for the librarian in developing and utilizing an effective reference collection. Arrangement is by broad subject groups; titles chosen are chiefly in English with geographic coverage limited to the United States and Canada. Texts in subject fields have been omitted since these are adequately covered in several comprehensive guides to the literature.

Blair, Edith D.

1967-01-01

21

Production of medical radionuclides with a 24 MeV proton cyclotron  

SciTech Connect

The CGR-MeV 520 cyclotron of Ghent University is used for the production of radionuclides for medical use. The radionuclides and simple labeled molecules produced are: /sup 81/Rb, /sup 13/NH/sub 3/, /sup 38/K and /sup 11/CO/sub 2/. The /sup 82/Kr(p,2n) /sup 81/Rb reaction on natural krypton gas is used to produce /sup 81/Rb. The entire procedure is remote-controlled. /sup 13/NH/sub 3/ is obtained by irradiation of water with 21 MeV protons, using the /sup 16/O(p,..cap alpha..)/sup 13/N reaction. The /sup 13/N-containing nitrates and nitrites are reduced to /sup 13/NH/sub 3/ with Devarda's alloy. /sup 38/K is obtained by irradiation of NaCl, of a saturated NaCl solution or of CCl/sub 4/ with 21 MeV ..cap alpha..particles, according to the /sup 35/Cl(..cap alpha..,n) /sup 38/K reaction. To produce /sup 11/CO/sub 2/, using the /sup 14/N(p,..cap alpha..)/sup 11/C reaction, N/sub 2/ gas is irradiated with 18 MeV protons. The /sup 11/C combines with traces of O/sub 2/ to yield /sup 11/CO/sub 2/. /sup 11/CO/sub 2/ is also used as a starting product for the synthesis of /sup 11/CH/sub 3/I. This can be used as a precursor to label more complex organic molecules.

Vandecasteele, C.

1981-04-01

22

A small-signal analysis of the electron cyclotron backward-wave oscillator  

Microsoft Academic Search

In an earlier report on the construction and performance of the electron cyclotron backward-wave oscillator, it was shown, through physical arguments, that in an unloaded waveguide supporting the dominant mode, an electron having transverse rotation at its cyclotron frequency will interact with RF fields of approximately equal frequency. This transverse motion will deliver energy to the RF E fields and

K. K. Chow; R. H. Pantell

1962-01-01

23

Measurement and control of the air contamination generated in a medical cyclotron facility for PET radiopharmaceuticals.  

PubMed

The aim of this paper is to report the data concerning the contamination of the exhausted air from the hot cells dedicated to the large-scale synthesis of positron emission tomography (PET) radiopharmaceuticals. Two cyclotrons are currently operating in Ospedale San Raffaele for the routine production of C and F. They are linked with four radiochemistry laboratories by means of shielded radioisotope delivery lines. The above labs are dedicated both to the large scale preparation and to the research and development of PET radiopharmaceuticals. The department hosts four CT-PET scanners, which operate with a mean patient workload of 40 per day. Radiosyntheses are performed using automated modules located in 10 hot cells. The air outlets are monitored online by a 2-inch NaI(Tl) counter in a Marinelli geometry counting volume. Contamination values up to 10(5) Bq L(-1) have been measured at the hot cell exit point during the synthesis. The corresponding concentrations at the point of release in atmosphere are largely above the threshold of 1.29 Bq L(-1), defined by national regulations as the limit for free environmental release. A shielded gas storage system controlled by a dedicated, customized software program has thus been installed to prevent the potentially hazardous release of gaseous radioactive contaminants. The system has allowed us to maintain the effective dose to neighboring population groups below the limit of 10 muSv y(-1). PMID:17440326

Calandrino, R; del Vecchio, A; Todde, S; Fazio, F

2007-05-01

24

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

25

Computerizing a Small Medical Practice Trading Tranquility for Tranquilizers  

PubMed Central

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

Adams, Richard C.

1979-01-01

26

Low Background-Rate Detector for Ions in the 5 to 50 KeV Energy Range to Be Used for Radioisotope Dating with a Small Cyclotron.  

National Technical Information Service (NTIS)

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 ...

P. G. Friedman

1986-01-01

27

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. Small, inexpensive cyclotrons serving this purpose would make the technique accessible to more researchers and inexpensive enough to compare many small samples. To this end, VC Berkeley is 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 -1/ counts/sec in the high-background environment of the cyclotron, where lower energy ions, electrons, and photons bombard the detector at much higher rates. To meet this challenge, an inexpensive, generally useful ion detector was developed 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 detector's 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.

Friedman, P.G.

1986-01-01

28

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.

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

2000-01-01

29

Course of Study: Medical Record Clerk Training Program. Student Manual for Medical Record Personnel in Small Rural Hospitals in Colorado.  

National Technical Information Service (NTIS)

A training program for medical record clerks in small, rural hospitals is provided. The objective of this program is to impart basic knowledge and develop the skills for medical record personnel and to develop an attitude in trained clerks which will lead...

1968-01-01

30

The cyclotron development activities at CIAE  

Microsoft Academic Search

The cyclotron has an obvious advantage in offering high average current and beam power. Cyclotron development for various applications, e.g. radioactive ion-beam (RIB) generation, clean nuclear energy systems, medical diagnostics and isotope production, were performed at China Institute of Atomic Energy (CIAE) for over 50years. At the moment two cyclotrons are being built at CIAE, the 100MeV, CYCIAE-100, and a

Tianjue Zhang; Zhenguo Li; Shizhong An; Zhiguo Yin; Jianjun Yang; Fang Yang

31

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

32

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

33

Radiotherapy Alone for Medically Inoperable Stage I Non-Small–Cell Lung Cancer: The Duke Experience  

Microsoft Academic Search

Purpose: To review our experience treating clinical Stage I non-small–cell lung carcinoma with radiotherapy alone using modern techniques and staging. The effect of dose and volume on outcome is to be analyzed.Methods: Between January 1980 and December 1995, 156 patients with Stage I medically inoperable non-small–cell lung cancer were irradiated at Duke University Medical Center and the Durham Veterans Administration

Gregory S. Sibley; Timothy A. Jamieson; Lawrence B. Marks; Mitchell S. Anscher; Leonard R. Prosnitz

1998-01-01

34

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

PubMed

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

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

2014-08-01

35

Isochronous cyclotron AIC-144 main parameters.  

National Technical Information Service (NTIS)

General technical description of the Cracow AIC-144 isochronous cyclotron is given as well as some of possible application of the facility in experimental physics, medical therapy and diagnostics, pharmacology, agriculture, metallurgy and radiochemistry. ...

J. Schwabe

1995-01-01

36

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

37

Development of a medical information system that minimizes staff workload and secures system safety at a small medical institution  

NASA Astrophysics Data System (ADS)

We developed a secure system that minimizes staff workload and secures safety of a medical information system. In this study, we assess the legal security requirements and risks occurring from the use of digitized data. We then analyze the security measures for ways of reducing these risks. In the analysis, not only safety, but also costs of security measures and ease of operability are taken into consideration. Finally, we assess the effectiveness of security measures by employing our system in small-sized medical institution. As a result of the current study, we developed and implemented several security measures, such as authentications, cryptography, data back-up, and secure sockets layer protocol (SSL) in our system. In conclusion, the cost for the introduction and maintenance of a system is one of the primary difficulties with its employment by a small-sized institution. However, with recent reductions in the price of computers, and certain advantages of small-sized medical institutions, the development of an efficient system configuration has become possible.

Haneda, Kiyofumi; Koyama, Tadashi

2005-04-01

38

Commercial cyclotrons. Part I: Commercial cyclotrons in the energy range 10–30 MeV for isotope production  

Microsoft Academic Search

A survey of commercial cyclotrons for production of medical and industrial isotopes is presented. Compact isochronous cyclotrons\\u000a which accelerate negative hydrogen ions in the energy range 10–30 MeV have been widely used over the last 25 years for production\\u000a of medical isotopes and other applications. Different cyclotron models for the energy range 10–12 MeV with moderate beam intensity\\u000a are used

A. I. Papash; Yu. G. Alenitsky

2008-01-01

39

Recent development and progress of IBA cyclotrons  

NASA Astrophysics Data System (ADS)

Several cyclotron development projects were recently realized by Ion Beam Applications S.A. (IBA). This contribution presents three of them: (i) the intensity enhancement of the Cyclone 30 cyclotron, a machine mainly used for the production of SPECT isotopes. This project is related with the increased demand for 201Tl because of the shortage of Mo/Tc generators from nuclear reactors, (ii) development of a new versatile multiple-particle K = 30 isotope-production cyclotron (the Cyclone 30XP) being able to accelerate H -, D - and also ?-particles. The ?-beam of this cyclotron will allow the production of new therapeutic isotopes (e.g. 211At) and (iii) commissioning of the Cyclone 70 cyclotron installed for Arronax in France. This machine is similar to the C30XP but provides higher energy ( K = 70) and allows research on new types of medical isotopes.

Kleeven, W.; Abs, M.; Delvaux, J. L.; Forton, E.; Jongen, Y.; Medeiros Romao, L.; Nactergal, B.; Nuttens, V.; Servais, T.; Vanderlinden, T.; Zaremba, S.

2011-12-01

40

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

PubMed Central

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

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

2014-01-01

41

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

PubMed

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

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

2010-01-01

42

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

ERIC Educational Resources Information Center

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

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

2007-01-01

43

Results and lessons learned from a small medical abortion clinical study in Turkey  

Microsoft Academic Search

This article presents results from a small, introductory clinical study offering a simplified regimen medical abortion to women in Turkey. A total of 208 women from five sites were recruited from July 2000 through March 2001. All eligible consenting women were given 200 mg oral mifepristone at the clinic followed by 400  ?g oral misoprostol 2 days later either at

Ayse Akin; Jennifer Blum; Sinan Özalp; Lütfü Öndero?lu; Üzeyir K?rca; Nihal Bilgili; Gonca Koço?lu; Neena Philip; Beverly Winikoff

2004-01-01

44

Superconducting cyclotrons at Michigan State University  

NASA Astrophysics Data System (ADS)

This paper describes the status of the three superconducting cyclotrons which are in operation or under construction at the National Superconducting Cyclotron Laboratory. The oldest of these, the K500, has been in operation since September 1982 supporting a national user program in heavy ion nuclear physics. A second large research cyclotron, the K800, is now nearing completion. This cyclotron will accelerate lighter heavy ions to 200 MeV/nuc and heavier particles up to energies given by 1200 Q2/ A MeV/nucleon. The magnet for this cyclotron came into operation in May 1984 and has performed smoothly and reliably in three extended operating periods. At present, K800 construction activity centers on fabrication and installation of the rf system, the extraction system, and the ECR injection line. The third NSCL superconducting cyclotron is a smaller 50 MeV deuteron cyclotron to be used for neutron therapy in the radiation oncology center of a major Detroit hospital (Harper Hospital). Design features of this small, application oriented, cyclotron are described in some detail.

Blosser, H. G.

45

Selected Lists of Journals for the Small Medical Library: A Comparative Analysis  

PubMed Central

The results of a survey and weighted summary of all major suggested journal subscription lists for hospital libraries are described. A total of ninety-one titles taken from 255 titles examined is listed under thirty-three subject headings. Contrasts are made of the titles and subject headings employed by others, and the potential of Stearns' “core collection” concept for small medical libraries is dealt with in detail.

Timour, John A.

1971-01-01

46

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

47

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.

2014-01-01

48

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

49

Hazardous medical waste generation in Greece: case studies from medical facilities in Attica and from a small insular hospital.  

PubMed

The accurate calculation of the unit generation rates and composition of medical waste generated from medical facilities is necessary in order to design medical waste treatment systems. In this work, the unit medical waste generation rates of 95 public and private medical facilities in the Attica region were calculated based on daily weight records from a central medical waste incineration facility. The calculated medical waste generation rates (in kg bed(-1) day( -1)) varied widely with average values at 0.27 ± 113% and 0.24 ± 121%, for public and private medical facilities, respectively. The hazardous medical waste generation was measured, at the source, in the 40 bed hospital of the island of Ikaria for a period of 42 days during a 6 month period. The average hazardous medical waste generation rate was 1.204 kg occupied bed(-1) day(-1) or 0.33 kg (official) bed( -1) day(-1). From the above amounts, 54% resulted from the patients' room (solid and liquid wastes combined), 24% from the emergency department (solid waste), 17% from the clinical pathology lab and 6% from the X-ray lab. In average, 17% of the total hazardous medical waste was solely infectious. Conclusively, no correlation among the number of beds and the unit medical waste generation rate could be established. Each hospital should be studied separately, since medical waste generation and composition depends on the number and type of departments/laboratories at each hospital, number of external patients and number of occupied beds. PMID:21242177

Komilis, Dimitrios; Katsafaros, Nikolaos; Vassilopoulos, Panagiotis

2011-08-01

50

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.

Brandon, A N; Hill, D R

1981-01-01

51

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.

Brandon, A N; Hill, D R

1979-01-01

52

Results and lessons learned from a small medical abortion clinical study in Turkey.  

PubMed

This article presents results from a small, introductory clinical study offering a simplified regimen medical abortion to women in Turkey. A total of 208 women from five sites were recruited from July 2000 through March 2001. All eligible consenting women were given 200 mg oral mifepristone at the clinic followed by 400 microg oral misoprostol 2 days later either at home or at the clinic. The overall success rate of 84.1% is lower than in previous studies of this regimen, and a surprisingly high proportion of women (9.1%) were diagnosed with incomplete abortion. In spite of the higher than expected failure rate, women expressed a high degree of satisfaction. Several challenges were faced during this study, providing valuable insights about ways to introduce medical abortion into new settings with the best chances for success. PMID:15504380

Akin, Ayse; Blum, Jennifer; Ozalp, Sinan; Ondero?lu, Lütfü; Kirca, Uzeyir; Bilgili, Nihal; Koço?lu, Gonca; Philip, Neena; Winikoff, Beverly

2004-11-01

53

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

54

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.

Brandon, A N; Hill, D R

1989-01-01

55

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.

Brandon, A N; Hill, D R

1985-01-01

56

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.

Brandon, A N; Hill, D R

1983-01-01

57

[Ways for optimization of treatment of patients with mesenterial thrombosis in municipal medical institutions of small towns and rural area].  

PubMed

An analysis of 199 cases has shown that verification of mesenterial thrombosis in municipal medical institutions is 5.6% at the prehospital period, 23% in the admission rooms of hospitals, 30%--in surgical departments before operation. The index of postoperative lethality remains high reaching 91.3% in municipal hospitals of Leningrad oblast. In order to improve results of treatment of patients with mesenterial thrombosis in municipal medical institutions of small towns and rural area it is necessary to develop technology and organization of medical aid in municipal medical institutions. PMID:20552800

Alekseev, T V; Movchan, K N; Beznosov, A I; Lozovski?, I F; Sidorenko, V A

2010-01-01

58

Improvements and applications at NIRS cyclotron facility  

NASA Astrophysics Data System (ADS)

The NIRS-Chiba isochronous cyclotron has been working in routinely, and providing the stable beams for bio-medical studies and various kind of related experiments since 1975. The clinical trail of eye melanoma has been under continued. Recently two new beam lines were constructed in order to carry out the bio-physical study, and to produce the long-lived R.I.s for SPECT. Some progressive improvements, such as updating the magnetic-channel and development of a floating septum system, were performed for stable operation of the cyclotron. A brief review of the current status of the cyclotron and typical application of latest experiments in the various fields are described. .

Honma, T.; Hojo, S.; Miyahara, N.; Nemoto, K.; Sato, Y.; Suzuki, K.; Takada, M.; Yamada, S.; Kuramochi, Y.; Okada, T.; Hanagasaki, M.; Komatsu, K.; Ogawa, H.

2001-12-01

59

The Warsaw K=160 cyclotron  

NASA Astrophysics Data System (ADS)

The overview of the Warsaw cyclotron facility is presented. The facility consists of K=160 cyclotron, 10 GHz ECR ion source, and several experimental stations. The cyclotron is of compact design with 2 straight dees. A yearly operation time is about 2900 hours on an average for the past few years. The cyclotron can deliver beams up to Ar with energy up to 10 MeV/amu to the experimental area. Experimental stations are: 1) The multidetector OSIRIS II, allows the study of exotic nuclei in the double magic 100Sn region. The experimental set-up consists of 8 HPGe detectors equipped with charged particle 4? multiplicity filter SiBall, 50 elements BGO ?-rays multiplicity filter, 4 sector polarimeter and electron conversion detector system. 2) CUDAC-Coulomb Universal Detector Scattering Chamber-an array of PIN-diodes in connection with HPGe detectors and the computer data analysis package GOSIA, maintained by the Laboratory allows investigation the Coulomb Excitation (COULEX) reactions. 3) IGISOL or Helium-jet transport system opened investigation of the reaction products by means of the online mass separator with ion-guide system. The system uses the Scandinavian-type mass separator built in INR ?wierk, Poland. 4) Giant Dipole Resonance studies using experimental set-up JANOSIK developed for the detection of high-energy photons emitted in heavy-ion collisions. The set-up consists of a large NaI(Tl) detector (25 cm×29 cm) surrounded by shields: passive lead shield, active anticoincidence plastic shield and LiH shield to absorb neutrons, and a multiplicity filter of 32 small scintillator detectors (BaF2 and NaI(Tl)). 5) Laser spectroscopy stand now in test phase. The laser spectroscopy group at HIL has completed an equipment consisting of Argon ion Laser Innova 400-25W in all lines and coherent Ring Laser 669-21 as well as atomic beam apparatus. .

Choinski, J.; Miszczak, J.; Sura, J.

2001-12-01

60

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

PubMed Central

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

Brandon, A N; Hill, D R

1997-01-01

61

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.

Brandon, A N; Hill, D R

1995-01-01

62

Support and Strategies for Change Among Small Patient-Centered Medical Home Practices  

PubMed Central

PURPOSE We aimed to determine the motivations and barriers facing small practices that seek to adopt the patient-centered medical home (PCMH) model, as well as the type of help and strategies they use. METHODS We surveyed lead physicians at practices with fewer than 5 physicians, stratified by state and level of National Committee for Quality Assurance PCMH recognition, using a Web-based survey with telephone, fax, and mail follow-up. The response rate was 59%, yielding a total sample of 249 practices from 23 states. RESULTS Improving quality and patient experience were the strongest motivations for PCMH implementation; time and resources were the biggest barriers. Most practices participated in demonstration projects or received financial rewards for PCMH, and most received training or other kinds of help. Practices found training and help related to completing the PCMH application to be the most useful. Training for patients was both less common and less valued. The most commonly used strategies for practice transformation were staff training, systematizing processes of care, and quality measurement/goal setting. The least commonly endorsed strategy was involving patients in quality improvement. Practices with a higher level of PCMH recognition were more likely to have electronic health records, to report barriers, and to use measurement-based quality improvement strategies. CONCLUSIONS To spread the adoption of the PCMH model among small practices, financial support, practical training, and other help are likely to continue to be important. Few practices involved patients in their implementation, so it would be helpful to test the impact of greater patient involvement in the PCMH.

Scholle, Sarah Hudson; Asche, Stephen E.; Morton, Suzanne; Solberg, Leif I.; Tirodkar, Manasi A.; Jaen, Carlos Roberto

2013-01-01

63

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.

Chiang, Michael F.; Starren, Justin B.

2002-01-01

64

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

PubMed

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

65

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

PubMed Central

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

Brandon, A N; Hill, D R

1993-01-01

66

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

PubMed

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

67

Activities at iThemba LABS Cyclotron Facilities  

NASA Astrophysics Data System (ADS)

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

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

68

Implementing Quality Improvement in Small, Autonomous Primary Care Practices: Implications for the Patient Centered Medical Home  

PubMed Central

Background Implementing improvement programs to enhance quality of care within primary care clinics is complex, with limited practical guidance available to help practices during the process. Understanding how improvement strategies can be implemented in primary care is timely given the recent national movement towards transforming primary care into patient-centered medical homes (PCMH). This study examined practice members’ perceptions of the opportunities and challenges associated with implementing changes in their practice. Methods Semi-structured interviews were conducted with a purposive sample of 56 individuals working in 16 small, community-based primary care practices. The interview consisted of open-ended questions focused on participants’ perceptions of: (1) practice vision, (2) perceived need for practice improvement, and (3) barriers that hinder practice improvement. The interviews were conducted at the participating clinics and were tape-recorded, transcribed, and content analyzed. Results Content analysis identified two main domains for practice improvement related to: (1) the process of care, and (2) patients’ involvement in their disease management. Examples of desired process of care changes included improvement in patient tracking/follow-up system, standardization of processes of care, and overall clinic documentations. Changes related to the patients’ involvement in their care included improving (a) health education, and (b) self care management. Among the internal barriers were: staff readiness for change, poor communication, and relationship difficulties among team members. External barriers were: insurance regulations, finances and patient health literacy. Practice Implications Transforming their practices to more patient-centered models of care will be a priority for primary care providers. Identifying opportunities and challenges associated with implementing change is critical for successful improvement programs. Successful strategy for enhancing the adoption and uptake of PCMH elements should leverage areas of concordance between practice members’ perceived needs and planned improvement efforts.

Arar, Nedal H.; Noel, Polly H.; Leykum, Luci; Zeber, John E.; Romero, Raquel; Parchman, Michael L.

2012-01-01

69

Medical Device and Supply Market: Market Success of Small Companies in Economic Recession  

Microsoft Academic Search

The rapid aging population is increasing and public and private healthcare policy changes in economic recession have provided challenges as well as numerous sales opportunities to medical device and supply industry. The purpose of this paper is to examine the impact of a combination of public and private healthcare policy changes and aging demography on medical device and supply market

Fred Gong; Lu Jia Sheng; Peibin Ke

2007-01-01

70

Cyclotron in 3D Model  

NSDL National Science Digital Library

This simulation illustrates the operation of a cyclotron, showing a charged particle moving through combined magnetic and electric fields. The particle, started near the center of the cyclotron, accelerates when passing through the gap between the electric electrodes and is turned by a perpendicular magnetic field. The geometry of the cyclotron, the magnitude of the electric and magnetic fields, and the properties of the charge are all adjustable. This page includes links to information on the operation of cyclotrons.

Hwang, Fu-Kwun; Wee, Loo K.

2010-12-10

71

The relative effect on the oxygen concentration in YBa sub 2 Cu sub 3 O sub 7 minus. delta. of atomic and ionic oxygen fluxes, produced by a small compact electron cyclotron resonance source  

SciTech Connect

The relative effect of atomic and ionic oxygen for the oxidation of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} thin films is investigated. To this goal, the characteristics of an oxygen plasma produced by a small, compact, permanent magnet electron cyclotron resonance plasma source were investigated as a function of a bias applied to the plasma. With no bias, a plasma potential of 23 eV was measured by an energy analysis of the ions. With increasing positive plasma bias voltage, the ion current decreases and its energy increases above the 23 eV by the amount of applied bias voltage. When a negative voltage is applied to the plasma, both electron and ion current drastically decrease, while the atomic flux remains high. The atomic oxygen flux was measured by the oxidation rate of Ag and the etching rate of a standard photoresist as a function of distance from the source and the bias voltage. We find that the resistivity of a YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} film in the plasma is well characterized by the flux of atomic oxygen and that there is no significant effect of oxygen ions.

Yamamoto, K.; Hammond, R.H. (Department of Applied Physics, Stanford University, Stanford, California (USA)); Harris, J.S. Jr. (Department of Electrical Engineering, Stanford University, Stanford, California (USA))

1991-09-01

72

Cyclotron Resonance in Magnesium.  

National Technical Information Service (NTIS)

Azbel'-Kaner cyclotron resonance has been studied at 22.9 GHz and 2 degrees K in the (10(-1)0), (11(-2)0), (0001), and (10(-1)1) planes of magnesium. Fifteen distinct mass series have been identified and their mass values determined as a function of the o...

D. A. Zych T. G. Eck

1969-01-01

73

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

ERIC Educational Resources Information Center

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

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

2004-01-01

74

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

75

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

76

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

77

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

78

Terrestrial kilometric radiation - The cyclotron theory  

NASA Technical Reports Server (NTRS)

It is shown that electrons in inverted V events can cause direct, amplified cyclotron emission (x-mode radiation) above the cutoff frequency, and the growth rate of the waves is calculated by using inverted V electron event observations as the inputs of a numerical code. Calculation results exhibiting wave growth are adduced as evidence for the cyclotron interpretation of terrestrial kilometric radiation (TKR). It is speculated that the specific electron distribution features which generate TKR should disappear in much less than a second, and should therefore not be observable in particle data averaged over more than one second. The basic electron distribution feature that gives rise to TKR is a one-sided loss cone anisotropy in which upward moving electrons with small pitch angles are missing. The features causing large growth rates may be due to the effects of the parallel electric field.

Melrose, D. B.; Hewitt, R. G.; Ronnmark, K. G.

1982-01-01

79

Aiming for Prevention: Medical and Public Health Approaches to Small Arms, Gun Violence, and Injury  

Microsoft Academic Search

The level of global small arms violence is enormous and the scale of human suffering it causes is immense, although poorly counted. It causes at least hundreds of thousands of deaths and more than a million injuries each year, as well as permanent physical and psychological damage, destruction of families, lost productivity, and diversion of resources from basic health services.

Brian Rawson

80

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

81

Small-Group Format for Continuing Medical Education: A Report from the Field.  

ERIC Educational Resources Information Center

For continuing education purposes, a group of 12-15 general practitioners held facilitated small-group discussions with experts. The groups provided practice-relevant topics, opportunity to compare practice patterns, and continuing education credits; they were motivating and effective. (SK)

Peloso, Paul M.; Stakiw, Ken J.

2000-01-01

82

The Effect of Student- and Teacher-Centered Small-Group Learning in Medical School on Knowledge Acquisition, Retention and Application.  

ERIC Educational Resources Information Center

Compares the effects of two types of small-group instruction on retention and application of gastroenterology knowledge during a gastroenterology pathophysiology course taught to 198 second-year medical students. Concludes that the specific format of small-group instruction appears to have little impact on retention or application of…

Kolars, Joseph C.; And Others

1997-01-01

83

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

NASA Astrophysics Data System (ADS)

NiTi shape memory alloys (SMA) are used for a variety of applications including medical implants and tools as well as actuators, making use of their unique properties. However, due to the hardness and strength, in combination with the high elasticity of the material, the machining of components can be challenging. The most common machining techniques used today are laser cutting and electrical discharge machining (EDM). In this study, we report on the machining of small structures into binary NiTi sheets, applying alternative processing methods being well-established for other metallic materials. Our results indicate that water jet machining and micro milling can be used to machine delicate structures, even in very thin NiTi sheets. Further work is required to optimize the cut quality and the machining speed in order to increase the cost-effectiveness and to make both methods more competitive.

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

2011-07-01

84

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

Hill, D R

1999-01-01

85

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

86

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

87

Helium cyclotron resonance within the earth's magnetosphere  

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

88

Relativistic Broadening Near Cyclotron Resonance.  

National Technical Information Service (NTIS)

Relativistic broadening of absorption (or emission) lines near cyclotron resonance in a warm plasma is investigated using the linearized relativistic Vlasov-Maxwell system. The unperturbed state is assumed to be isotropic, but not necessarily Maxwellian. ...

K. Imre H. Weitzner

1983-01-01

89

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

90

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

91

Cyclotron-resonance-maser arrays  

Microsoft Academic Search

The cyclotron-resonance-maser (CRM) array is a radiation source which consists of CRM elements coupled together under a common magnetic field. Each CRM-element employs a low-energy electron-beam which performs a cyclotron interaction with the local electromagnetic wave. These waves can be coupled together among the CRM elements, hence the interaction is coherently synchronized in the entire array. The implementation of the

Eli Jerby; Amit Kesar; Michael Korol; L. Lei; Vladimir Dikhtyar

1999-01-01

92

Shielding calculations for Inshas cyclotron  

NASA Astrophysics Data System (ADS)

Methods used in shielding calculations for the cyclotron vault and experimental rooms of Egypt's first cyclotron laboratory to be erected at the premises of the Nuclear Research Center, Atomic Energy Authority (Inshas) are discussed. Use is made of the removal diffusion theory and of the techniques presented in NCRP-51, Wall and ceiling dimensions are estimated based on radiation protection norms given in the ICRP-60 as issued in 1991.

Comsan, M. N. H.

1996-05-01

93

Stimulated electromagnetic emission near electron cyclotron harmonics in the ionosphere  

Microsoft Academic Search

Observations of electromagnetic emission stimulated by a high-frequency radio wave injected into the ionosphere from a ground-based powerful transmitter operated near harmonics of the ionospheric electron cyclotron frequency are reported. Significant changes in the spectrum of the stimulated electromagnetic radiation were obtained as the injected frequency was varied in small steps around these harmonics. The experimental results are attributed to

T. B. Leyser; B. Thide; H. Derblom; A. Hedberg; B. Lundborg; P. Stubbe; H. Kopka; M. Rietveld

1989-01-01

94

Comparison of neutron fluxes in an 18-MeV unshielded cyclotron room and a 16.5-MeV self-shielded cyclotron room.  

PubMed

Some medical compact cyclotrons have self-shielding to reduce neutron fluxes. Thermal neutron fluxes in an 18-MeV unshielded cyclotron room and in a 16.5-MeV self-shielded cyclotron room were evaluated. In addition, the radioactivities in concrete and metals due to thermal neutrons in the cyclotron rooms for 30 years were calculated of operation such that the sum of the ratio of the nuclide concentration to the nuclide clearance level was equal to 1. The thermal neutron flux from the unshielded cyclotron was approximately 10(2) cm(-2) s(-1), whereas that from the self-shielded cyclotron was approximately 10(2) cm(-2) s(-1). The thermal neutron fluxes for concrete, stainless steel, vessel steel, and aluminum that reached their clearance levels were 9.80 × 10(4), 2.17 × 10(3), 1.87 × 10(4), and 2.41 × 10(5) cm(-2) s(-1), respectively. The specific activities in the cyclotron room were found to be sufficiently below the clearance level when the self-shield was employed. PMID:22447045

Fujibuchi, Toshioh; Horitsugi, Genki; Yamaguchi, Ichiro; Eto, Akihisa; Iwamoto, Yasuo; Obara, Satoshi; Iimori, Takashi; Masuda, Yoshitada; Watanabe, Hiroshi; Hatazawa, Jun

2012-07-01

95

An all permanent magnet electron cyclotron resonance ion source for heavy ion therapya)  

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

96

'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

97

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

98

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.

2012-01-01

99

Ion Temperature Gradient Driven Drift Cyclotron Instabilities.  

National Technical Information Service (NTIS)

The role of ion temperature gradient driven drift cyclotron instabilities in both mirror machines and tokamaks is examined. Destabilizing temperature gradient modifications to the drift cyclotron loss cone mode are found to exist even when the loss cone i...

P. J. Catto R. E. Aamodt

1977-01-01

100

Use of cyclotrons in medicine  

NASA Astrophysics Data System (ADS)

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

Qaim, S. M.

2004-10-01

101

Helium cyclotron resonance within the earth's magnetosphere  

Microsoft Academic Search

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

B. H. Mauk; C. E. McIlwain; R. L. McPherron

1981-01-01

102

The Cyclotron Resonance Backward-Wave Oscillator  

Microsoft Academic Search

An electron injected into a longitudinal magnetic field with some initial transverse motion will rotate at the cyclotron frequency in the transverse plane. If an RF electric field, which is polarized in the transverse plane and which oscillates at the cyclotron frequency, is present, a cumulative energy interchange between the electron and the field will occur. This principle of cyclotron

K. K. Chow; R. H. Pantell

1960-01-01

103

Solid-State Cyclotron Maser.  

National Technical Information Service (NTIS)

A solid-state cyclotron maser for generating low power (1 watt or less) signals in the submillimeter frequency range (300 GHz-30,000 GHz) includes an accelerating region, a drift region, and a metal grid therebetween. Both regions are formed from semicond...

A. K. Ganguly K. L. Davis K. R. Chu

1983-01-01

104

Ion sources for cyclotron applications  

SciTech Connect

The use of a multicusp plasma generator as an ion source has many advantages. The development of both positive and negative ion beams based on the multicusp source geometry is presented. It is shown that these sources can be operated at steady state or cw mode. As a result they are very suitable for cyclotron operations.

Leung, K.N.; Bachman, D.A.; McDonald, D.S.; Young, A.T.

1992-07-01

105

Negative mass cyclotron resonance maser  

Microsoft Academic Search

Physical principles, design and operation characteristics of a negative mass cyclotron resonance maser inp-type germanium are considered in this paper. The formation of anisotropic inverted distributions of negative effective mass heavy holes in strong electric and magnetic fieldsE ?H ? [001], resulting in negative conductivity in the millimetre and submillimetre wavelength ranges, is discussed. The generation is observed at? ˜

V. I. Gavrilenko; Z. F. Krasil'nik

1991-01-01

106

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

107

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

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

108

Pharmacist Staffing and the Use of Technology in Small Rural Hospitals: Implications for Medication Safety. Working Paper No. 1.  

National Technical Information Service (NTIS)

This paper reports the results of a national study that assesses the capacity of rural hospitals to implement medication safety practices, with particular focus on pharmacist staffing and the availability of technology. The primary data for the project wa...

G. Davidson I. Moscovice M. M. Casey

2005-01-01

109

RF-PROPERTIES OF THE VE-RFQ-INJECTOR FOR THE ISL-CYCLOTRON  

Microsoft Academic Search

The separated sector cyclotron at the ISL (Ionen-Strahl- Labor, Berlin) will get a new injector. The RFQ-part of the injector consists of two closely coupled VE- (Variable Energy) RFQs with an input energy range of 15 to 30 keV\\/n and an output energy range of 90 to 360 keV\\/n. For direct injection into the cyclotron a small energy spread and

O. Engels; A. Schempp; H. Homeyer; W. Pelzer

110

Theory of gyro-travelling-wave tubes at cyclotron harmonics  

Microsoft Academic Search

The generalized theory of gyro-travelling-wave tubes operating at arbitrary cyclotron harmonics is developed taking into account the transverse drift of electron guiding centres. In the framework of small-signal theory, the dispersion equation is obtained and analysed and a problem of spurious counterpropagating waves excitation is discussed. The results of the large-signal theory are presented, which predict a high efficiency of

G. S. NUSINOVICH; H. LI

1992-01-01

111

Electron cyclotron heating in NSTX  

NASA Astrophysics Data System (ADS)

Heating and current drive by electron cyclotron waves in high magnetic field tokamaks is commonly done by coupling power from the low-field side to the O-mode. However, for tokamaks with ?pe/?ce>1, such as the spherical tokamak NSTX, the O-mode is cutoff throughout most of the plasma. An alternative method for accessing the cyclotron layer is via the fast X-mode and its mode conversion to an electron-Bernstein wave (EBW)[1]. We show that for a given plasma density and magnetic field profile, an appropriate choice of the frequency allows one to form a triplet (cutoff-resonance-cutoff) X to EBW mode-conversion scenario. This is similar to the low-frequency, ion-ion hybrid resonance scenario for which 100% mode conversion was shown to be possible[2]. The mode-conversion efficiency for DIII-D and NSTX is calculated.

Wu, K. C.; Ram, A. K.; Bers, A.; Schultz, S. D.

1997-04-01

112

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

113

Variable frequency RFQs as cyclotron injectors  

Microsoft Academic Search

Injectors for cyclotrons must provide low emittance beams with variable energy and bunch repetition frequency. The parameters of standard RFQs, which are short duty factor and constant operating frequency are not favourable for cyclotron application. Our development of the VE-RFQ has been adopted to match the HMI-cyclotron at HMI in Berlin as a first variable frequency RFQ operating in cw-mode.

A. Schempp

2001-01-01

114

High performance computation on beam dynamics problems in high intensity compact cyclotrons  

NASA Astrophysics Data System (ADS)

This paper presents the research progress in the beam dynamics problems for future high intensity compact cyclotrons by utilizing the state-of-the-art high performance computation technology. A "Start-to-Stop" model, which includes both the interaction of the internal particles of a single bunch and the mutual interaction of neighboring multiple bunches in the radial direction, is established for compact cyclotrons with multi-turn extraction. This model is then implemented in OPAL-CYCL, which is a 3D object-oriented parallel code for large scale particle simulations in cyclotrons. In addition, to meet the running requirement of parallel computation, we have constructed a small scale HPC cluster system and tested its performance. Finally, the high intensity beam dynamics problems in the 100 MeV compact cyclotron, which is being constructed at CIAE, are studied using this code and some conclusions are drawn.

Yang, JianJun; Zhang, TianJue; Lin, YuZheng; Adelmann, Andreas; Wang, Feng; An, ShiZhong

2011-12-01

115

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

Microsoft Academic Search

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

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

2010-01-01

116

Fluid theory of beam spiraling in high intensity cyclotrons  

NASA Astrophysics Data System (ADS)

Novel uses of cyclotrons for basic science, national security and medical therapy applications require the production of beams with ever higher intensities. At these high intensities, uncontrolled beam loss must be minimized. To satisfy the stringent beam loss criteria, it is crucial to have a detailed understanding of the beam dynamics in high intensity cyclotrons, and more specifically, an understanding of the effects of space charge on the dynamics. Using a two-dimensional fluid description, we investigate the nonlinear radial-longitudinal dynamics of intense beams in cyclotrons. With a multiscale analysis separating the time scale associated with the betatron motion and the slower time scale associated with space-charge effects, we show that the longitudinal-radial vortex motion can be understood in the frame moving with the charged beam as the nonlinear advection of the beam by the ExB velocity field, where E is the electric field due to the space charge and B is the external magnetic field. This interpretation provides simple explanations for the stability of round beams and for the development of spiral halos in elongated beams. By numerically solving the advection equation, we show that it is also in quantitative agreement with results obtained in PIC simulations.

Cerfon, Antoine; Parra, Felix; Freidberg, Jeffrey

2012-10-01

117

Cyclotron Line Measurements with INTEGRAL  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

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

Superconducting booster cyclotron studies at GANIL.  

National Technical Information Service (NTIS)

Work is beginning at GANIL on the study of a booster cyclotron SSC3 giving a maximum energy around 500 MeV/A for light ions. SSC3 could be a separated sector cyclotron using superconducting coils. First results concerning these studies are reported. (ERA ...

C. Bieth, P. Bricault, A. Chabert, M. Duval, J. Ferme

1990-01-01

120

The Evergreen State College Cyclotron Project  

Microsoft Academic Search

We have designed a multipurpose cyclotron device, which may be used to conduct a variety of experiments. We are building our device in stages. Our first stage is a FT-ICR spectrometer, which uses an array of induction coils to monitor orbits in the chamber. We will then take the signal and subject it to the Fourier transform, yielding the cyclotron

Amandeep Dhillon; Paul Lessard; Chris Small

2006-01-01

121

Geomagnetic cyclotron resonance in living cells  

Microsoft Academic Search

Although considerable experimental evidence now exists to indicate that low-frequency magnetic fileds influence living cells, the mode of coupling remains a mystery. We propose a radical new model for electromagnetic interactions with cells, one resulting from a cyclotron resonance mechanism attached to ions moving through transmembrane channels. It is shown that the cyclotron resonance condition on such ions readily leads

Abraham R. Liboff

1985-01-01

122

Electron Cyclotron Resonance (ECR) Plasma Thruster Research  

Microsoft Academic Search

A study is being made on an electric propulsion system (EICR Plasma Thruster) which can generate plasma with ECRH (Electron Cyclotron Resonance Heating), accelerate ions with ICRFH (Ion Cyclotron Range of Frequency Heating) via antenna, and adopts a gradient in magnetic field to obtain thrust. The plasma thruster could achieve high power density and long lifetime since this system does

H. Nakashima; Y. Takao; Y. Mori; K. Uemura; T. Gouda; T. Miyamoto; T. Esaki; T. Maeyama; T. Muranaka

2000-01-01

123

Cyclotron Resonance in a Nonneutral Plasma.  

National Technical Information Service (NTIS)

Single component plasmas are found to exhibit a reversal in the roles of cyclotron and upper hybrid resonances familiar in neutral plasmas. There is a global resonance at the cyclotron frequency omega = Omega = qB/mc and a local field cancellation at laye...

S. A. Prasad G. J. Morales B. D. Fried

1985-01-01

124

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

125

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

SciTech Connect

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

Sher, David J., E-mail: dsher@lroc.harvard.edu [Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA (United States); Center for Outcomes and Policy Research, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA (United States); Wee, Jon O. [Department of Thoracic Surgery, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA (United States); Punglia, Rinaa S. [Department of Radiation Oncology, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA (United States); Center for Outcomes and Policy Research, Dana-Farber Cancer Institute/Brigham and Women's Hospital, Boston, MA (United States)

2011-12-01

126

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

127

The experience of the clinical photographer, when working in both large and small medical illustration departments in the UK.  

PubMed

Working in a large department with an assorted staff of photographers, managers, graphic designers and administrators numbering thirty-plus is a radically different experience from working in a department that numbers two or three. The authors of this paper have both worked in large and small departments and were quite surprised by the similarities and differences between these two working experiences. Their impressions are shared here. PMID:20557162

Grice, Katherine; Treen, Nicola

2010-06-16

128

Excitation of cyclotron resonances from random fluctuations of stellarator windings  

NASA Astrophysics Data System (ADS)

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 energy from the axial to transverse direction. These random displacements become completely harmless when their maximum amplitude is reduced to +/-0.5 mm. When even such small displacements cannot be attained, the errors that are produced from the mispositioning of the windings may become benign by using a crowbar on the current of the windings before the critical resonance is reached. At l=m (~= 6 in our case), where l is the value of the cyclotron mode and m is the value of field periods in the device, i.e., when the frequency of the cyclotron mode is equal to the frequency of the strong focusing mode, the beam centroid encounters a potent resonance and locks in at it, even when the windings are located at their ideal positions. If crossing of the l=m=6 mode is desired, using a crowbar on the strong focusing field may be the only remedy.

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

1996-03-01

129

Design & construction status of CYCIAE-100, a 100 MeV H - cyclotron for RIB production  

NASA Astrophysics Data System (ADS)

For productions of intense proton and radioactive ion beam (RIB) used in fundamental and applied research, e.g. neutron physics, nuclear structure, material and life sciences and medical isotope production, a new RIB facility, Beijing radioactive ion-beam facility (BRIF) had been started at CIAE since 2004. In this project, a 100 MeV H - cyclotron is selected as the driving accelerator. It will provide a 75-100 MeV, 200-500 ?A proton beam. In this paper, BRIF will be described briefly. Then, various aspects about the 100 MeV cyclotron including the general description, specification, beam dynamics, design and construction status of the magnet, RF system etc. will be described respectively. And some R&D, including the CRM (Central Region Model) cyclotron, LLRF control, 10 mA H - source etc. for this machine will also be illustrated in this paper.

Zhang, Tianjue; Li, Zhenguo; Yin, Zhiguo; Cyciae-100 Project Team

2008-10-01

130

Application of compact electron cyclotron resonance ion source  

SciTech Connect

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

Muramatsu, M.; Kitagawa, A.; Iwata, Y.; Ogawa, H.; Hojo, S.; Kubo, T.; Kato, Y.; Biri, S.; Fekete, E.; Yoshida, Y.; Drentje, A. G. [Graduate School of Mechanical Engineering, Toyo University, Tokyo 112-8606, Japan and National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan); National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555 (Japan); Department of Electrical, Electronic and Information Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Institute of Nuclear Research (ATOMKI), H-4026 Debrecen, Bem ter 18/c (Hungary); Department of Mechanical Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-0815 (Japan); National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan and K.V.I. University of Groningen, 9747 AA Groningen (Netherlands)

2008-02-15

131

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

132

Variable frequency RFQs as cyclotron injectors  

NASA Astrophysics Data System (ADS)

Injectors for cyclotrons must provide low emittance beams with variable energy and bunch repetition frequency. The parameters of standard RFQs, which are short duty factor and constant operating frequency are not favourable for cyclotron application. Our development of the VE-RFQ has been adopted to match the HMI-cyclotron at HMI in Berlin as a first variable frequency RFQ operating in cw-mode. Another example ist the RFQ at RIKEN which injects into the RILAC variable frequency linac. The layout and properties of these RFQs will be described. .

Schempp, A.

2001-12-01

133

Nonlinear evolution of electromagnetic ion cyclotron waves  

SciTech Connect

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

Silin, I.; Sydora, R. D.; Mann, I. R.; Sauer, K. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2G7 (Canada); Mace, R. L. [School of Physics, University of KwaZulu-Natal, Durban 4000 (South Africa)

2011-04-15

134

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

SciTech Connect

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

Chang, Joe Y., E-mail: jychang@mdanderson.org [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Komaki, Ritsuko; Wen, Hong Y.; De Gracia, Beth; Bluett, Jaques B.; McAleer, Mary F. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Swisher, Stephen G. [Department of Thoracic/Cardiovascular Surgery, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Gillin, Michael; Mohan, Radhe [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Cox, James D. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

2011-08-01

135

Electron cyclotron wave generation by relativistic electrons  

NASA Astrophysics Data System (ADS)

We show that an energetic electron distribution which has a temperature anisotropy (T perpendicular to b is greater than T parallel to b), or which is gyrating about a DC magnetic field, can generate electron cyclotron waves with frequencies below the electron cyclotron frequency. Relativistic effects are included in solving the dispersion equation and are shown to be quantitatively important. The basic idea of the mechanism is the coupling of the beam mode to slow waves. The unstable electron cyclotron waves are predominantly electromagnetic and right-hand polarized. For a low-density plasma in which the electron plasma frequency is less than the electron cyclotron frequency, the excited waves can have frequencies above or below the electron plasma frequency, depending upon the parameters of the energetic electron distribution. This instability may account for observed Z mode waves in the polar magnetosphere of the Earth and other planets.

Wong, H. K.; Goldstein, M. L.

1994-01-01

136

Electron Cyclotron Emission from the PLT Tokamak.  

National Technical Information Service (NTIS)

Experimental measurements of electron cyclotron emission from the PLT tokamak plasma reveal that black-body emission occurs at the fundamental frequency. Such emission, not possible by direct thermal excitation of electromagnetic waves, is herein attribut...

J. Hosea V. Arunasalam R. Cano

1977-01-01

137

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

138

Resonant Cyclotron Scattering in Magnetars' Emission  

Microsoft Academic Search

We present a systematic fit of a model of resonant cyclotron scattering (RCS) to the X-ray data of 10 magnetars, including canonical and transient anomalous X-ray pulsars (AXPs) and soft gamma repeaters (SGRs). In this scenario, nonthermal magnetar spectra in the soft X-rays (i.e., below ~10 keV) result from resonant cyclotron scattering of the thermal surface emission by hot magnetospheric

Nanda Rea; Silvia Zane; Roberto Turolla; Maxim Lyutikov; D. Götz

2008-01-01

139

Recent development and progress of IBA cyclotrons  

Microsoft Academic Search

Several cyclotron development projects were recently realized by Ion Beam Applications S.A. (IBA). This contribution presents three of them: (i) the intensity enhancement of the Cyclone 30 cyclotron, a machine mainly used for the production of SPECT isotopes. This project is related with the increased demand for 201Tl because of the shortage of Mo\\/Tc generators from nuclear reactors, (ii) development

W. Kleeven; M. Abs; J. L. Delvaux; E. Forton; Y. Jongen; L. Medeiros Romao; B. Nactergal; V. Nuttens; T. Servais; T. Vanderlinden; S. Zaremba

140

Pure cyclotron spectra of V405 Aur  

NASA Astrophysics Data System (ADS)

In this study we investigate the pure cyclotron spectra of an Intermediate Polar (IP), V405 Aur, which has the highest magnetic field strength in its class. Recent studies have shown that cyclotron harmonics are seen in the spectra of V405 Aur. We assume that cyclotron harmonics are produced by electrons having a streaming bi-Maxwellian velocity profile found in the lower portions of the accretion column connecting to the magnetic poles of the white dwarf in V405 Aur system. Then we applied the Green function for a dispersive medium such as the one found in V405 Aur. Further we assume that the cyclotron radiation is produced at Ordinary and Extraordinary wave modes. We find the general solution of the Green function for the Extraordinary wave mode and a dispersive medium and we derived the pure cyclotron spectra from the Green function. This function enabled us to calculate energy radiated per unit wavelength per unit solid angle as a function of wavelength which revealed the sixth, seventh and the eighth harmonics which correspond to the observed values. Our model produces the observed cyclotron spectrum of V405 Aur.

Tutar, Demet; Rennan Pekünlü, E.

2013-02-01

141

The Cyclotron Group at the Metallurgical Laboratory, Chicago, 1940-44  

Microsoft Academic Search

A small supplement to the official history of the Manhattan Project is offered in that some of the activities of the Cyclotron Group in the Metallurgical Laboratory are described. In particular, the work on the delayed neutron activities was essential to the decision to try for the first nuclear chain reaction in the middle of Chicago, and fast-neutron measurements in

Arthur H. Snell; H. Bradner; J. E. Brolley; M. Camac; B. D. Kern; J. S. Levinger; E. P. Meiners; A. C. G. Mitchell; V. A. Nedzel; W. Rall; M. B. Sampson; R. G. Wilkinson

1980-01-01

142

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

143

Simultaneous excitation of broadband electrostatic noise and electron cyclotron waves in the plasma sheet  

NASA Technical Reports Server (NTRS)

Electron cyclotron harmonics and broadband electrostatic noise (BEN) are often observed in the earth's outer plasma sheet. While it is well known that ion beams in the plasma sheet boundary layer can generate BEN, new two-dimensional electrostatic simulations show that field-aligned ion beams with a small perpendicular ring distribution can drive not only BEN, but also electron cyclotron harmonic (ECH) waves simultaneously. Simulation results are presented here using detailed diagnostics of wave properties, including dispersion relations of all wave modes.

Berchem, Jean P.; Schriver, David; Ashour-Abdalla, Maha

1991-01-01

144

Electron cyclotron subharmonic resonance absorption  

NASA Astrophysics Data System (ADS)

Nonlinear absorption of electromagnetic waves propagating through a plasma perpendicular to the uniform magnetic field at a frequency close to electron cyclotron subharmonic frequency is investigated by studying the dynamics of individual particle motion. The motion of the electron is described using a relativistic Hamiltonian formalism. Second-order canonical perturbation theory is carried out to explicitly obtain the subharmonic response. When the variation in the parameters of the dynamical system is slow, the motion of the particles is characterized by a conserved adiabatic invariant equal to the area embedded by the trajectory in phase space. The energy gain of an electron has been obtained in terms of the change in the adiabatic invariant resulting from a qualitative change in the phase orbit of the electron. A case of strong nonlinearity is considered in which the energy absorbed by an electron from the wave is greater than its thermal energy. The amount of absorbed power is computed analytically for the case of ordinary-mode polarization. (c) 1995 The American Physical Society

Janaki, M. S.; Dasgupta, B.

1995-12-01

145

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

146

Beam dynamics in high intensity cyclotrons including neighboring bunch effects: Model, implementation, and application  

NASA Astrophysics Data System (ADS)

Space-charge effects, being one of the most significant collective effects, play an important role in high intensity cyclotrons. However, for cyclotrons with small turn separation, other existing effects are of equal importance. Interactions of radially neighboring bunches are also present, but their combined effects have not yet been investigated in any great detail. In this paper, a new particle in the cell-based self-consistent numerical simulation model is presented for the first time. The model covers neighboring bunch effects and is implemented in the three-dimensional object-oriented parallel code OPAL-cycl, a flavor of the OPAL framework. We discuss this model together with its implementation and validation. Simulation results are presented from the PSI 590 MeV ring cyclotron in the context of the ongoing high intensity upgrade program, which aims to provide a beam power of 1.8 MW (CW) at the target destination.

Yang, J. J.; Adelmann, A.; Humbel, M.; Seidel, M.; Zhang, T. J.

2010-06-01

147

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

148

Design & construction status of CYCIAE-100, a 100 MeV H ? cyclotron for RIB production  

Microsoft Academic Search

For productions of intense proton and radioactive ion beam (RIB) used in fundamental and applied research, e.g. neutron physics, nuclear structure, material and life sciences and medical isotope production, a new RIB facility, Beijing radioactive ion-beam facility (BRIF) had been started at CIAE since 2004. In this project, a 100MeV H? cyclotron is selected as the driving accelerator. It will

Tianjue Zhang; Zhenguo Li; Zhiguo Yin

2008-01-01

149

CYCIAE-100, a 100 MeV H ? cyclotron for RIB production  

Microsoft Academic Search

For productions of intense proton and radioactive ion beam (RIB) used in fundamental and applied researches, e.g. neutron physics, nuclear structure, material and life sciences and medical isotope production, a new RIB facility, Beijing Radioactive Ion-beam Facility (BRIF) was started in CIAE since 2004. For this project, a 100MeV H? cyclotron is selected as the driving accelerator, providing a 75–100MeV,

Tianjue Zhang; Zhenguo Li; Chengjie Chu

2007-01-01

150

100 MeV H- CYCLOTRON AS AN RIB DRIVING ACCELERATOR 1  

Microsoft Academic Search

For productions of intense proton and radioactive ion beam (RIB) used in fundamental and applied research, e.g., neutron physics, nuclear structure, material and life sciences and medical isotope production, a new RIB facility, Beijing Radioactive Ion-beam Facility (BRIF) is started in CIAE recently. In this project, a 100 MeV H- cyclotron is selected as the driving accelerator. It will provide

Tianjue Zhang

151

Laser separation of medical isotopes  

Microsoft Academic Search

There is an increasing demand for different separated isotopes as feed material for reactor and cyclotron-produced radioisotopes used by a fast-growing radiopharmaceutical industry. One new technology that may meet future demands for medical isotopes is molecular laser isotope separation (MLIS). This method was investigated for the enrichment of uranium in the 1970`s and 1980s by Los Alamos National Laboratory, Isotope

J. W. Eerkens; D. A. Puglishi; W. H. Miller

1996-01-01

152

General Electric PETtrace cyclotron as a neutron source for boron neutron capture therapy  

NASA Astrophysics Data System (ADS)

This research investigates the use of a PETtrace cyclotron produced by General Electric (GE) as a neutron source for boron neutron capture therapy (BNCT). The GE PETtrace was chosen for this investigation because this type of cyclotron is popular among nuclear pharmacies and clinics in many countries; it is compact and reliable; it produces protons with energies high enough to produce neutrons with appropriate energy and fluence rate for BNCT and it does not require significant changes in design to provide neutrons. In particular, the standard PETtrace 18O target is considered. The cyclotron efficiency may be significantly increased if unused neutrons produced during radioisotopes production could be utilized for other medical modalities such as BNCT at the same time. The resulting dose from the radiation emitted from the target is evaluated using the Monte Carlo radiation transport code MCNP at several depths in a brain phantom for different scattering geometries. Four different moderating materials of various thicknesses were considered: light water, carbon, heavy water, arid Fluental(TM). The fluence rate tally was used to calculate photon and neutron dose, by applying fluence rate-to-dose conversion factors. Fifteen different geometries were considered and a 30-cm thick heavy water moderator was chosen as the most suitable for BNCT with the GE PETtrace cyclotron. According to the Brookhaven Medical Research Reactor (BMRR) protocol, the maximum dose to the normal brain is set to 12.5 RBEGy, which for the conditions of using a heavy water moderator, assuming a 60 muA beam current, would be reached with a treatment time of 258 min. Results showed that using a PETtrace cyclotron in this configuration provides a therapeutic ratio of about 2.4 for depths up to 4 cm inside a brain phantom. Further increase of beam current proposed by GE should significantly improve the beam quality or the treatment time and allow treating tumors at greater depths.

Bosko, Andrey

153

Interpretive Experiments: An Interpretive Experiment in Ion Cyclotron Resonance Spectroscopy.  

ERIC Educational Resources Information Center

Provides a discussion which is intended for chemistry college students on the ion cyclotron resonance (ICR) spectroscopy, the physical basis for ion cyclotron resonance, and the experimental methodology employed by ICR spectroscopists. (HM)

Burnier, R. C.; Freiser, B. S.

1979-01-01

154

Analysis of gamma ray burst spectra with cyclotron lines.  

National Technical Information Service (NTIS)

Motivated by the recent developments in the cyclotron resonance upscattering of soft photons or CUSP model of Gamma Ray Burst (GRB) continuum spectra, we revisit a select database of GRBs with credible cyclotron absorption features. We measure the break e...

V. Kargatis E. P. Liang

1990-01-01

155

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

156

Calcium cyclotron resonance and diatom mobility.  

PubMed

The hypothesis that movement of biological ions may be predicted by cyclotron resonance theory applied to cell membranes is tested in these experiments. Diatoms (Amphora coffeaeformis) were chosen as the biosystem since they move or don't move, depending on how much calcium is transported across the membrane. The experiments demonstrate that a particular ion (calcium) is apparently moved across the cell membrane in response to the DC and AC values of magnetic flux densities (B) and the frequency derived from the cyclotron resonance theory. A clear resonance is shown and a rather sharp frequency response curve is demonstrated. The experiments also show a dose response as the AC value of the flux density is varied, and that odd harmonics of the basic cyclotron frequency are also effective. PMID:3663247

Smith, S D; McLeod, B R; Liboff, A R; Cooksey, K

1987-01-01

157

Cyclotron maser emission: Stars, planets, and laboratory  

SciTech Connect

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

2011-05-15

158

Phase space characterization of an internal ion source for cyclotrons  

Microsoft Academic Search

Orbit tracking codes are used to predict the behavior of the beam in a cyclotron before the cyclotron is constructed by tracking many orbits which collectively are intended to represent the beam. Cyclotrons with internal ion sources (such as the series of 250 MeV proton beam cancer therapy cyclotrons being manufactured by ACCEL Instruments GmbH of Bergisch-Gladbach Germany) present difficulty

Edward Russell Forringer

2004-01-01

159

Numerical simulations on electrostatic hydrogen cyclotron instabilities  

SciTech Connect

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

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

1981-02-01

160

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

161

Wave propagation across ion cyclotron resonance harmonic layers  

SciTech Connect

Wave propagation across ion cyclotron resonance layers is investigated by use of a boundary layer analysis for a perpendicularly stratified, weakly inhomogeneous plasma. Corresponding to the situation in many plasmas of interest, it is assumed that the wave frequency is much less than the ion plasma frequency, but that the ratio of ion plasma frequency to wave frequency times the ratio of ion thermal speed to the speed of light is small. Non-trivial effects of the cyclotron resonance appear in the boundary layer and modify the current from the cold plasma limit. These corrections suggest the breakdown of the geometrical optics limit. Wave equations for the field valid within an arbitrary harmonic resonance layer are derived, as well as for the two ion hybrid resonance case. Analytical proofs of reciprocity relations are given for the general wave propagation problems. For fundamental resonance, second harmonic resonance, and ion-ion hybrid resonance proofs of the properties that the transmission coefficient remains the same as its geometrical optics value, and the absence of reflection of the fast mode incident from the high field side are given. Numerical results for the cases of fundamental, second, and third ion resonances, and for the ion-ion hybrid resonance are presented.

Imre, K.; Weitzner, H.

1987-08-01

162

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

Microsoft Academic Search

An electron cyclotron emission (ECE) receiver inside the electron cyclotron resonance heating (ECRH) transmission line has been brought into operation. The ECE is extracted by placing a quartz plate acting as a Fabry-Perot interferometer under an angle inside the electron cyclotron wave (ECW) beam. ECE measurements are obtained during high power ECRH operation. This demonstrates the successful operation of the

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

2008-01-01

163

Test Coil for the Superconducting SUSE Cyclotron.  

National Technical Information Service (NTIS)

In the context of the project study for the super-conducting SUSE cyclotron as accelerator for the existing 13 MN tandem at the Munich Accelerator Laboratory, a superconducting main coil was built full-size and tested. The triangular coil (2.3 m wide, 2.7...

U. Schneider

1985-01-01

164

Ion-cyclotron instability in magnetic mirrors  

SciTech Connect

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

Pearlstein, L.D.

1987-02-02

165

Challenges for the ITER ion cyclotron system.  

National Technical Information Service (NTIS)

Ion cyclotron heating is one of the methods proposed for heating and for driving current in the ITER plasma. The ITER environment is significantly different from that of present day tokamak because of heating from neutrons and from the high radiated heat ...

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

1997-01-01

166

DTs-1 Deuteron Cyclotron Accelerating System.  

National Technical Information Service (NTIS)

Calculation of the main parameters of the accelerating system of the DTs-1 deuteron cyclotron for designed energy 1 MeV/turn is performed. The accelerating system is a half-wave delta-resonator with TEM-wave with vertical resonance lines. The lost power a...

A. A. Glazov E. N. Zaplatin

1986-01-01

167

Electric-field ion cyclotron resonance.  

PubMed

We consider the possibility that DC magnetic fields can interact in a resonant manner with endogenous AC electric fields in biological systems. Intrinsic electric-field ion cyclotron resonance (ICR) interactions would be more physically credible than models based on external AC magnetic fields and might be expected as an evolutionary response to the long-term constancy of the geomagnetic field. PMID:9125238

Liboff, A R

1997-01-01

168

Electric-field ion cyclotron resonance  

Microsoft Academic Search

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

Liboff

1997-01-01

169

Slow-Wave Wideband Cyclotron Amplifier.  

National Technical Information Service (NTIS)

A slow-wave, cyclotron-type, travelling-wave-tube amplifier in which the beam-wave interaction is the result of a Weibel-type instability. The travelling wave is slowed down in its propagation through the waveguide by a dielectric liner located on the inn...

P. A. Sprangle V. L. Granatstein

1980-01-01

170

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

171

Numerical investigation of auroral cyclotron maser processes  

SciTech Connect

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.; Robertson, C. W.; Whyte, C. G.; He, W. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG, Scotland (United Kingdom); Bingham, R. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG, Scotland (United Kingdom); Rutherford Appleton Laboratory, Space Physics Division, STFC, Didcot OX11 0QX (United Kingdom); Vorgul, I.; Cairns, R. A. [School of Mathematics and Statistics, University of St. Andrews, St. Andrews KY16 9SS, Scotland (United Kingdom); Kellett, B. J. [Rutherford Appleton Laboratory, Space Physics Division, STFC, Didcot OX11 0QX (United Kingdom)

2010-05-15

172

THEORY OF NEGATIVE-MASS CYCLOTRON RESONANCE  

Microsoft Academic Search

It was recently suggested that the re-entrant energy contours of the ; heavy-hole bands in Ge and Si could contribute a negative resistivity component ; to the overall resistivity of these materials, possibly related to a non-; equilibrium density of carriers in these re-entrant states. Such a phenomenon ; could be observed under cyclotron resonance conditions as an emission spectrum

D. C. Mattis; M. J. Stevenson

1959-01-01

173

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

174

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

175

Production of flickering aurora and field-aligned electron flux by electromagnetic ion cyclotron waves  

NASA Technical Reports Server (NTRS)

Recent observations have suggested that flickering aurora is produced by a modulation of the field-aligned component of the electron flux within an auroral arc. It is proposed that a portion of the field-aligned electrons are of ionospheric origin and that these electrons are accelerated and their flux modulated by electromagnetic ion cyclotron waves that occur below the main acceleration region on auroral arc field lines. A model of the electromagnetic ion cyclotron wave shows that the parallel phase velocity of the wave increase as the wave propagates toward the ionosphere. A test particle calculation shows that ionospheric electrons trapped or reflected by the wave are accelerated to energies of several keV and that their flux is modulated at the wave frequency. The relative amplitudes of the model wave electric fields are consistent with the observations of small-scale low-frequency ionospheric and magnetospheric electric fields near auroral arcs of approximately 10 mV/m and 100 mV/m, respectively. The large-amplitude ion cyclotron waves also produce a ponderomotive force and a self-consistent ambipolar electric field. Energy considerations show that the downward energy flux in the electromagnetic ion cyclotron wave can be several percent of the total downward auroral electron energy flux.

Temerin, M.; Mcfadden, J.; Boehm, M.; Carlson, C. W.; Lotko, W.

1986-01-01

176

Observations of narrowband ion cyclotron waves on the surface of the Moon in the terrestrial magnetotail  

NASA Astrophysics Data System (ADS)

By examining the data collected by the Apollo 15 and 16 Lunar Surface Magnetometers between April and July of 1972, we have found a class of narrowband waves observed at the surface of the Moon. With frequencies ranging from 0.04 to 0.17 Hz, these narrowband waves were present only when the Moon was in the terrestrial magnetotail, and the wave properties are consistent with those of ion cyclotron waves. We propose two scenarios where anisotropies of ion temperature can occur in the vicinity of the Moon to excite the ion cyclotron waves observed at the lunar surface. Simultaneous observations at the Apollo 15 and 16 sites revealed small but persistent differences in wave amplitude and phase, suggesting that the wave signals were modified by the mini-magnetosphere above the Apollo 16 site. It is also suggested that subsurface electrical conductivity may possibly be involved in the amplitude change and small phase difference between the two sites.

Chi, P. J.; Russell, C. T.; Wei, H. Y.; Farrell, W. M.

2013-12-01

177

Experimental study of an ion cyclotron resonance accelerator  

NASA Astrophysics Data System (ADS)

The Ion Cyclotron Resonance Accelerator (ICRA) uses the operating principles of cyclotrons and gyrotrons. The novel geometry of the ICRA allows an ion beam to drift axially while being accelerated in the azimuthal direction. Previous work on electron cyclotron resonance acceleration used waveguide modes to accelerate an electron beam [5]. This research extends cyclotron resonance acceleration to ions by using a high field superconducting magnet and an rf driven magnetron operating at a harmonic of the cyclotron frequency. The superconducting solenoid provides an axial magnetic field for radial confinement and an rf driven magnetron provides azimuthal electric fields for acceleration. The intent of the ICRA concept is to create an ion accelerator which is simple, compact, lightweight, and inexpensive. Furthermore, injection and extraction are inherently simple since the beam drifts through the acceleration region. However, use of this convenient geometry leads to an accelerated beam with a large energy spread. Therefore, the ICRA will be most useful for applications which do not require a monoenergetic beam. An ICRA designed to accelerate protons to 10 MeV would be useful for the production of radioisotopes, or neutron beams, as well as for materials science applications. As a first step toward producing an ICRA at useful energies, a low energy ICRA has been designed, built, and tested as a demonstration of the concept. Analytical theory and a full computer model have been developed for the ICRA. Beam measurements taken on the ICRA experiment have been compared with theory. The ICRA computer model uses realistic fields of the solenoid, magnetron, and electrostatic bend. This code tracks single particle trajectories from the ion source through the entire system to a target face. A full emittance injected beam can be modeled by tracking many single particle trajectories. The ICRA experiment is designed to accelerate a proton beam from 5 keV to 50 keV in 5 turns. A superconducting solenoid provides a 2.5 Tesla axial magnetic field. The accelerating structure built for the experiment operates at 152 MHz (4th harmonic) and provides 3 kV across 8 gaps. Measurements of the accelerated beam current vs. beam orbit radius indicate an energy distribution ranging from near zero to near the full design energy, with 7% of the beam current above 24 keV and 1% above 42 keV. Energy distributions generated using the ICRA computer model show reasonable agreement with the experimental data. After a small correction of the bend voltage, the computer model shows good agreement with the magnitude and shape of the experimental data for a wide range of turn number. Finally, a scheme for optimization of the basic ICRA design is given. Design parameters are identified which minimize cost and which maximize the accelerated beam current. Three 10 MeV proton designs are given which offer a compromise between low cost and a high quality beam.

Ramsell, Christopher T.

2000-11-01

178

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.??

Rowell, N; Williams, C

2001-01-01

179

Comparison of outcomes for patients with medically inoperable Stage I non-small-cell lung cancer treated with two-dimensional vs. three-dimensional radiotherapy  

SciTech Connect

Purpose: This retrospective analysis was performed to assess the outcomes of three-dimensional (3D) conformal radiotherapy and two-dimensional (2D) planning. Methods and Materials: Between 1978 and 2003, 200 patients with Stage I non-small-cell lung cancer (NSCLC) were treated with radiotherapy alone at M.D. Anderson Cancer Center. Eighty-five patients were treated with 3D conformal radiotherapy. For the 3D group, median age, radiation dose, and follow-up was 73 (range, 50-92), 66 Gy (range, 45-90.3 Gy), and 19 months (range, 3-77 months), respectively; and for the 2D group, 69 (range, 44-88), 64 Gy (range, 20-74 Gy), 20 months (range, 1-173 months), respectively. Overall survival (OS), disease-specific survival (DSS), disease-free survival (DFS), locoregional control (LRC), and distant metastasis-free survival (DMFS) rates were analyzed. Results: There was no statistically significant difference in patient and tumor characteristics between 2D and 3D groups, except the 3D patients were older (p = 0.006). The OS, DSS, and LRC rates were significantly higher in patients who were treated by 3D conformal radiotherapy. Two- and 5-year OS for the 3D group were 68% and 36%, respectively, and 47% and 10% in the 2D group (p = 0.001). DSS at 2 and 5 years for the 3D group were 83% and 68%, respectively, vs. 62% and 29% in the 2D group (p < 0.001). LRC rates at 2 and 5 years for patients in the 3D group were 77% and 70% and 53% and 34% in the 2D group (p < 0.001). On univariate analysis elective, nodal irradiation was associated with decreased OS, DSS, and LRC. On multivariate analysis, 3D conformal radiotherapy was associated with increased OS and DSS. Male sex, age {>=}70, weight loss {>=}5%, and tumor size {>=}4 cm were associated with decreased OS and DSS. Conclusions: This study demonstrates that 3D conformal radiotherapy improves outcomes in patients with medically inoperable Stage I NSCLC compared with 2D treatment and is an acceptable treatment for this group of patients.

Fang, L. Christine [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Komaki, Ritsuko [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States)]. E-mail: rkomaki@mdanderson.org; Allen, Pamela [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Guerrero, Thomas [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Mohan, Radhe [Department of Radiation Physics, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States); Cox, James D. [Department of Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston, TX (United States)

2006-09-01

180

Cyclotron effects in relativistic backward-wave oscillators operating at low magnetic fields  

Microsoft Academic Search

A small-signal theory of a resonant relativistic backward-wave oscillator (BWO) operating at a very low-guiding magnetic field is developed. The theoretical approach is based on the successive iteration method of analytical solution of the exact three dimensional (3-D) equations of electrons motion. It was shown that cyclotron resonance effects in relativistic BWO (400 kV) operating at low-focusing magnetic field can

Alexander N. Vlasov; Anton S. Ilyin; Yuval Carmel

1998-01-01

181

Estimation of the cyclotron mass from the de Haas-van Alphen oscillation in the two-dimensional and quasi-two-dimensional multiband systems  

NASA Astrophysics Data System (ADS)

It is known that a cyclotron mass is obtained by fitting a temperature dependence of the Fourier harmonics of the de Haas-van Alphen oscillation to the temperature reduction factor in the Lifshitz-Kosevich (LK) formula in which the oscillation of the chemical potential is neglected. The LK formula, however, should be applied carefully in two-dimensional (2D) and quasi-two-dimensional (Q2D) systems at low temperatures, where the magnetic-field dependence of the chemical potential cannot be neglected. We compare the effective cyclotron mass, which is estimated by using the temperature reduction factor for the fixed chemical potential, with the cyclotron mass of the system. The cyclotron mass is fairly well obtained in 2D single-band systems when the density of states of the reservoir is negligible or much larger than the density of states of the 2D band. On the other hand, if the reservoir has the same order of the density of states as the 2D band, the effective cyclotron mass is shown to be estimated about 7% larger at low temperature and high field. In the 2D multiband systems the effective cyclotron mass for the heavier mass is underestimated about 9%, while the lighter effective cyclotron mass is obtained with very small errors.

Kishigi, Keita; Hasegawa, Yasumasa

2005-07-01

182

Orbit correction in an orbit separated cyclotron  

NASA Astrophysics Data System (ADS)

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

Plostinar, C.; Rees, G. H.

2014-04-01

183

ADHD Medications  

MedlinePLUS

Managing ADHD With Medication Just about everyone has trouble concentrating or paying attention in class from time to time. ... to develop new medications for ADHD. Continue Are ADHD Medications Safe? Most experts agree that ADHD medications ...

184

Medication Guide  

MedlinePLUS

... before starting any new medication. First-Line Medications: Nicotine Replacement Therapy (NRT) These medications are called "first- ... they might try a "second-line" medication instead. Nicotine replacement therapy (NRT) helps smokers quit by reducing ...

185

High intensity H- cyclotrons for radioisotope production  

Microsoft Academic Search

A description is given of Cyclone 30, a 30-MeV, H- cyclotron for radioscope production, designed for extremely high extracted beam intensity (500 ?A) and low power consumption (less than 100 kW with a 15-kW extracted beam). The Cyclone 30 prototype has now been operational for years at Louvain-La-Neuve and has achieved all design goals while demonstrating very high reliability. The

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

1989-01-01

186

Analytical techniques with a cyclotron on polymers  

Microsoft Academic Search

Nuclear analytical techniques (PIXE, RBS and ERDA) have been applied to investigate diffusion processes in polymer light-emitting\\u000a diodes (PLEDs), employing a 30 MeV AVF cyclotron. The techniques prove to be useful in identifying the origin of the diffusion\\u000a process and the nature of molecules transported from the hole injecting ITO electrode into the polymer layer.

M P De Jong; M J A De Voigt; L J Van Ijzendoorn; H H Brongersma

1999-01-01

187

Ion cyclotron waves in the Io torus: Wave dispersion, free energy analysis, and SO 2 + source rate estimates  

Microsoft Academic Search

As the Galileo spacecraft passed through the I0 torus, ion cyclotron waves were observed near the sulfur dioxide ion gyrofrequency. The toms plasma is continually replenished by the ionization of neutral particles from I0. It is well known that sulfur dioxide dissociates rapidly, so that the corotating toms plasma consists of predominantly sulfur and oxygen ions. However, for the small

D. E. Huddleston; R. J. Strangeway; J. Warnecke; C. T. Russell; M. G. Kivelson

1998-01-01

188

Improving cancer treatment with cyclotron produced radionuclides  

SciTech Connect

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

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

1992-08-04

189

ITER Ion Cyclotron Heating and Fueling Systems  

SciTech Connect

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

Rasmussen, D.A. [Oak Ridge National Laboratory (United States); Baylor, L.R. [Oak Ridge National Laboratory (United States); Combs, S.K. [Oak Ridge National Laboratory (United States); Fredd, E. [Princeton Plasma Physics Laboratory (United States); Goulding, R.H. [Oak Ridge National Laboratory (United States); Hosea, J. [Princeton Plasma Physics Laboratory (United States); Swain, D.W. [Oak Ridge National Laboratory (United States)

2005-04-15

190

Operation of a quasioptical electron cyclotron maser  

SciTech Connect

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

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

1984-12-01

191

Cyclotron Requirements for Multi-disciplinary Programs  

SciTech Connect

As time has passed, the various Cyclotron programs have changed over the years. In the ''early'' times of Cyclotron operations, the emphasis was on a more single sided approach such as Clinical or Research or Production. However, as time passed, the disciplines became more interconnected until today, it is unusual to have a Cyclotron and only have a single program unless it is pure production. More and more, especially in public areas such as Universities or Health Centers, you are seeing programs that do all three types of disciplines: Production; Clinical or Patient Diagnostics and/or Treatment; and Research, either in the development and manufacture of new Radio-Isotopes, new Diagnostic or Therapeutic Compound Development, or Clinical Research involving subject testing. While all three of these disciplines have some common requirements, they also have some very different requirements that may be completely counterproductive to other requirements. For a program where all three disciplines are required to be successful, it is necessary come up with some sort of compromise that meets all the various requirements. During this talk, we will try to identify some of these different requirements for the various disciplines and how these could impact the other disciplines. We will also discuss ideas for some possible compromises that might reduce the conflict between the various disciplines.

Armbruster, John M. [IBA Molecular, 3601 Morgantown Industrial Park, Morgantown, WV 26501 (United States)

2009-03-10

192

Nonlinear Cyclotron Absorption and Stimulated Scattering  

NASA Astrophysics Data System (ADS)

In electron cyclotron resonance heating (ECRH) wave sources heat a plasma linearly with respect to intensity, but as the intensity of ECRH gets larger, there might appear nonlinear effects that would result in cutoff of net absorption. This thesis uses quantum mechanical theory to derive a threshold microwave intensity for nonlinear absorption. The quantum mechanical theory estimates that the threshold microwave intensity for nonlinear absorption is about 10('5) watts/cm('2) for a microwave heating experiment (T(,e) = 100 ev, (lamda) = 3.783 cm, B = 2.5 kG). This value seems large considering the present power capabilities of microwave sources (10('2) (TURN) 10('3) watts/cm('2)), but for a low temperature plasma, this threshold will go down. There is another nonlinear phenomenon called stimulated cyclotron scattering which enhances photon scattering by electrons gyrating in a magnetic field. This is expected to prevent incoming photons from arriving at the central region of the fusion plasma, where absorption mainly takes place. Theory based on a photon transport model predicts that the threshold intensity for the stimulated cyclotron scattering is about 10('4) watts/cm('2) for the plasma parameters mentioned above. This value seems large also, but a longer wavelength of microwaves and a larger magnitude magnetic field, which will be the case in reactor type facilities, will lower the threshold intensity to levels comparable with the currently developed microwave sources.

Chung, Tae Hun

193

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

194

Simulations of ion cyclotron anisotropy instabilities in the terrestrial magnetosheath  

NASA Technical Reports Server (NTRS)

Enhanced transverse magnetic fluctuations observed below the proton cyclotron frequency in the terrestrial magnetosheath have been identified as due to the proton cyclotron and helium cyclotron instabilities driven by the T-perpendicular greater than T-parallel condition of the sheath ions. One-dimensional hybrid computer simulations are used here to examine the nonlinear properties of these two growing modes at relatively weak fluctuation energies and for wave vectors parallel to the background magnetic field. Second-order theory predicts fluctuating magnetic field energies at saturation of the proton cyclotron anisotropy instability in semiquantitative agreement with the simulation results. Introduction of the helium component enhances the wave-particle exchange rate for proton anisotropy reduction by that instability, thereby reducing the saturation energy of that mode. The simulations demonstrate that wave-particle interactions by the proton cyclotron and helium cyclotron instabilities lead to the anticorrelation observed by Anderson and Fuselier (1993).

Gary, S. P.; Winske, Dan

1993-01-01

195

Ensemble Simulations of Proton Heating in the Solar Wind via Turbulence and Ion Cyclotron Resonance  

NASA Astrophysics Data System (ADS)

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

Cranmer, Steven R.

2014-07-01

196

Current driven electrostatic and electromagnetic ion cyclotron instabilities  

NASA Technical Reports Server (NTRS)

Growth rates and parameter dependences are calculated for the current driven instabilities of electrostatic (with finite-beta corrections) and electromagnetic ion cyclotron waves. For 0.25 (T sub e)/(T sub i) 2.5, ion cyclotron waves have large growth rates, while ion acoustic waves are still stable. In fusion devices, where electrostatic waves may be stable, electromagnetic ion cyclotron waves are unstable for beta sub i 0.001.

Forslund, D. W.; Kennel, C. F.; Kindel, J. M.

1971-01-01

197

Optimal cyclotron radius for high resolution FT-ICR spectrometry  

NASA Astrophysics Data System (ADS)

Many factors shift the cyclotron frequency of ions trapped in a Fourier transform ion cyclotron resonance (FT-ICR) trap. The major factors are radial components of the trapping electric field, ion axial displacements from the center of the trap, space charge density, and relativistic mass increase. It is shown that the ion post-excitation radius is the most crucial factor that influences the cyclotron frequency. For an elongated cyclindrical FT-ICR trap, the analytical expressions of the cyclotron frequency shifts for the various factors are derived. They are useful for precise mass measurements carried out on an FT-ICR mass spectrometer.

Gorshkov, Michael V.; Nikolaev, Eugene N.

1993-05-01

198

Electrostatic electron and ion cyclotron harmonic waves in Neptune's magnetosphere  

NASA Technical Reports Server (NTRS)

Voyager 2 observations of electrostatic electron and ion cyclotron waves detected in Neptune's magnetosphere are presented. Both types of emission appear in a frequency band above the electron and ion (proton) cyclotron frequencies, respectively, and are tightly confined to the magnetic equator occurring within a few degrees of it. The electron cyclotron modes including an intense upper hybrid resonance emission excited by an unstable loss cone distribution of low-density superthermal electrons. The ion cyclotron waves are interpreted as hydrogen Bernstein modes including an intense lower hybrid resonance emission excited by an unstable ring distribution of low-density pickup N(+) ions deriving from the satellite Triton.

Barbosa, D. D.; Kurth, W. S.; Cairns, I. H.; Gurnett, D. A.; Poynter, R. L.

1990-01-01

199

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

200

Production of Short-Lived Radiopharmaceuticals with CV-28 Cyclotron. Final Report for the Period 1 June 1981-14 July 1984.  

National Technical Information Service (NTIS)

A variable energy isochronous cyclotron CV-28 at the Physical Department of the Instituto de Engenharia Nuclear in Rio de Janeiro, Brazil, is used for radionuclide production of medical interest. The production methods of sup 67 Ga, sup 77 Br, sup 111 In,...

A. Gerbasi da Silva

1985-01-01

201

Fundamental ion cyclotron resonance heating of JET deuterium plasmas  

SciTech Connect

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

Krasilnikov, A. V. [Troitsk Institute of Nuclear Physics (TRINITI), Russia; Van Eester, D. [Laboratory for Plasma Physics-ERM/KMS (LPP-ERM/KMS), Brussels, Belgium; Lerche, E. [Laboratory for Plasma Physics-ERM/KMS (LPP-ERM/KMS), Brussels, Belgium; Ongena, J. [Laboratory for Plasma Physics-ERM/KMS (LPP-ERM/KMS), Brussels, Belgium; Amosov, V. N. [Troitsk Institute of Nuclear Physics (TRINITI), Russia; Biewer, Theodore M [ORNL; Bonheure, G. [Laboratory for Plasma Physics-ERM/KMS (LPP-ERM/KMS), Brussels, Belgium; Crombe, K. [Ghent University, Belgium; Ericsson, G. [Uppsala University, Uppsala, Sweden; Esposito, Basilio [ENEA, Frascati; Giacomelli, L. [Uppsala University, Uppsala, Sweden; Hellesen, C. [Uppsala University, Uppsala, Sweden; Hjalmarsson, A. [Uppsala University, Uppsala, Sweden; Jachmich, S. [EURATOM / UKAEA, UK; Kallne, J. [Uppsala University, Uppsala, Sweden; Kaschuck, Yu A [Troitsk Institute of Nuclear Physics (TRINITI), Russia; Kiptily, V. [EURATOM / UKAEA, UK; Leggate, H. [EURATOM / UKAEA, UK; Mailloux, J. [EURATOM / UKAEA, UK; Marocco, D. [ENEA, Frascati; Mayoral, M.-L. [EURATOM / UKAEA, UK; Popovichev, S. [EURATOM / UKAEA, UK; Riva, M. [ENEA, Frascati; Santala, M. [EURATOM / UKAEA, UK; Stamp, M. F. [EURATOM / UKAEA, UK; Vdovin, V. [Russian Research Center, Kurchatov Institute, Moscow, Russia; Walden, A. [EURATOM / UKAEA, UK

2009-03-01

202

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

SciTech Connect

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

Mcdonald, Ross D [Los Alamos National Laboratory; Ayala - Valenzuela, Oscar E [Los Alamos National Laboratory; Altarawneh, Moaz M [Los Alamos National Laboratory; Analytis, James G [STANFORD UNIV/SLAC; Chu, J. H. [STANFORD UNIV/SLAC; Fisher, R. [STANFORD UNIV/SLAC

2011-01-14

203

Formation of wave-front pattern accompanied by current-driven electrostatic ion-cyclotron instabilities  

SciTech Connect

Formation of a wave-front pattern accompanied by an electrostatic ion-cyclotron instability driven by electrons drifting along a magnetic field is investigated by two-and-half dimensional particle simulations. A clear spatial wave-front pattern appears as the ion cyclotron wave grows due to the instability. When the electron stream is uniform in the system, an obliquely intersected stripe wave-front pattern is formed. When the stream has a bell-shaped pattern across the magnetic field, a V-shaped stripe wave-front pattern appears. The wave fronts have small angles with the magnetic field lines and propagate from the high-stream region to the low-stream region. {copyright} {ital 1997 American Institute of Physics.}

Ishiguro, S. [Department of Electronic Engineering, Tohoku University, Sendai 980-77 (Japan)] [Department of Electronic Engineering, Tohoku University, Sendai 980-77 (Japan); Sato, T.; Takamaru, H.; Watanabe, K. [Theory and Computer Simulation Center, National Institute for Fusion Science, Nagoya 464-01 (Japan)] [Theory and Computer Simulation Center, National Institute for Fusion Science, Nagoya 464-01 (Japan); Complexity Simulation Group

1997-08-01

204

Large-signal theory of gyro traveling wave tubes in cyclotron harmonics  

SciTech Connect

A nonlinear theory of gyro traveling wave tubes (gyro-TWT's) at cyclotron harmonics has been developed taking into account the electron velocity spread and the possibility of operating with significant Doppler frequency up-shift (CARM operation). In this paper, the authors will show that the orbital efficiency of the relativistic gyro-TWT operating at the second cyclotron harmonic with large frequency up-conversion may exceed 60%. We also show that the influence of the axial inhomogeneity of the wave field on the relation between amplitudes of electric and magnetic fields of the wave causes small changes in the efficiency of gyro-TWT's. The results obtained demonstrate the sensitivity of the harmonic gyro-TWT efficiency with respect to electron velocity spread at different axial wave numbers. In the final section of the paper the expressions for the gain are derived and discussed.

Nusinovich, G.S.; Li, H. (Lab. for Plasma Research, Univ. of Maryland, College Park, MD (US))

1992-06-01

205

75 FR 48939 - National Superconducting Cyclotron Laboratory of Michigan State University; Notice of Decision on...  

Federal Register 2010, 2011, 2012, 2013

...International Trade Administration National Superconducting Cyclotron Laboratory of Michigan State...Constitution Ave., NW., Washington, DC. Docket Number: 10-043. Applicant: National Superconducting Cyclotron Laboratory of Michigan...

2010-08-12

206

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

207

[Electron cyclotron resonance (ECR) plasma film deposition  

SciTech Connect

During the third quarter of 1995, an electron cyclotron resonance (ECR) plasma film deposition facility was constructed at the University of New Mexico. This work was conducted in support of the Los Alamos/Tycom CRADA agreement to pursue methods of improving drill bit lifetime. Work in the fourth quarter will center on the coating of drill bits and the treating and testing of various test samples. New material systems as well as treatment techniques will be attempted during this period. The following is a brief description of the various subsystems of the film deposition facility. Particular emphasis is placed on the slotted waveguide system as requested.

NONE

1999-04-01

208

Medical Assistants  

MedlinePLUS

... uses. Medical assistants should not be confused with physician assistants , who examine, diagnose, and treat patients under a ... learn their skills through on-the-job training. Physicians or other medical assistants may teach a new assistant medical terminology, the ...

209

Medication Treatments  

MedlinePLUS

... medications are used to treat certain symptoms of Fragile X syndrome, as shown in the chart below. The NICHD ... of these medications in treating the symptoms of Fragile X syndrome, or for other conditions for which the medications ...

210

Beam tests of the VE-RFQ cyclotron injector  

Microsoft Academic Search

The new VE-RFQ-injector for the cyclotron at HMI in Berlin is now being commissioned. The ECR-source together with the RFQs supply heavy ion beams with 90-360 keV\\/u for q\\/A>0.15 matched to the isochronous cyclotron. Properties of the new injector and results of first beam tests are presented

F. Hollering; O. Engels; A. Schempp; J. Hauser; H. Hohmeyer; W. Pelzer; A. Denker

1999-01-01

211

Small-Scale Wide-Range Medical Ozonator with Built-In Photometric Measurement Device of Ozone Concentration, Based on Solid-State Elements  

Microsoft Academic Search

Development results of a wide-range medical ozonator equipped with ozone concentration measurement device are presented in the paper. The ozone synthesis was carried out with a microsecond pulsed-periodical barrier discharge with automatic preliminary ionization. The ozone output concentration is 0.1-80 mg\\/1, volumetric rate of an output flow is from 0.1 1\\/min up to 1 1\\/min. To measure the ozone concentration

S. N. Buranov; A. B. Buyanov; S. V. Voyevodin; V. V. Gorokhov; V. I. Karelin; Yu. N. Lashmanov; V. D. Selemir; N. M. Selemir; P. V. Suchkov

2005-01-01

212

Impurity cyclotron resonance of anomalous Dirac electrons in graphene.  

PubMed

We have investigated a new feature of impurity cyclotron resonances common to various localized potentials of graphene. A localized potential can interact with a magnetic field in an unexpected way in graphene. It can lead to formation of anomalous boundstates that have a sharp peak with a width R in the probability density inside the potential and a broad peak of size magnetic length ? outside the potential. We investigate optical matrix elements of anomalous states and find that they are unusually small and depend sensitively on the magnetic field. The effect of many-body interactions on their optical conductivity is investigated using a self-consistent time-dependent Hartree-Fock approach. For a completely filled Landau level we find that an excited electron-hole pair, originating from the optical transition between two anomalous impurity states, is nearly uncorrelated with other electron-hole pairs, although it displays substantial exchange self-energy effects. This absence of correlation is a consequence of a small vertex correction in comparison to the difference between renormalized transition energies computed within the one electron-hole pair approximation. However, an excited electron-hole pair originating from the optical transition between a normal and an anomalous impurity state can be substantially correlated with other electron-hole states with a significant optical strength. PMID:25049042

Kim, S C; Yang, S-R Eric; MacDonald, A H

2014-08-13

213

Beam analysis system for Texas A & M K500 cyclotron  

NASA Astrophysics Data System (ADS)

A beam analysis system has been designed to provide a dispersion of 19.3 cm per % {?P}/{P} with an ultimate aberration limited resolution of {?E}/{E} up to {1}/{2500} for the full emittance of beams from the Texas A&M K500 cyclotron. Both dispersion matched and slit limited solutions for beam delivered to the MDM spectrometer were obtained. A total of 175 degrees of bend, in opposite direction 88 and 87 degree segments, is used with an intermediate focus between the segments. The first half may be used as a lower resolution analysis system with the second half serving to remove slit scattered particles so that a very clean beam can be transported to the MDM spectrometer for zero degree inelastic scattering measurements. The system is designed to use seven small inexpensive n = 0 dipoles with eight quadrupoles to provide focusing. Techniques for tuning are developed and the stability of the solutions with small changes in focusing are explored.

Youngblood, D. H.; Bronson, J. D.

1995-02-01

214

Cyclotron frequency multiplication in Cherenkov backward-wave oscillators  

SciTech Connect

In relativistic Cherenkov backward-wave oscillators, the output radiation is usually formed by a forward wave, which arises due to reflection of the operating backward wave from the input end of the operating waveguide. In this paper, we propose to use the resonant cyclotron absorption of this forward wave as a way to produce the secondary, stimulated cyclotron radiation at a multiplied frequency and a high cyclotron harmonic. Along with the 'simple' cyclotron resonance, the high-frequency wave can be emitted also in the regime of a combined resonance caused by nonresonant cyclotron interaction of electrons with the backward low-frequency wave. Existence of combined resonances helps provide the frequency synchronization, as well as to improve the electron-wave interaction at the multiplied frequency.

Savilov, A. V. [Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod, 603950 (Russian Federation)

2009-06-15

215

Concept and utilization of a regional cyclotron center  

NASA Astrophysics Data System (ADS)

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

Emran, Ali M.

1993-06-01

216

Fundamental and harmonic electron cyclotron maser emission  

NASA Technical Reports Server (NTRS)

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

Winglee, R. M.

1985-01-01

217

Phase Resolved Cyclotron Spectroscopy of Polars  

NASA Astrophysics Data System (ADS)

This research was conducted through the REU program at Cerro Tololo Interamerican Observatory in La Serena, Chile. For this research we reduced and modeled phase-resolved cyclotron spectroscopy of four AM Her stars: MN Hya, HU Aqu, VV Pup, and QS Tel. Two of the four spectra show good cyclotron harmonics while the other two were taken during a high state with too much noise in the spectra. Using a Constant-Lambda code (Schwope et al., 1990) we modeled the two good spectra and further modeled the harmonic motion of HU Aqr. The models produced for MN Hya gave parameters with a magnetic field strength between 44 MG and 43.4 MG, a plasma temperature between 4.1 keV and 5.6 keV, a log ? of 4.2 ± 0.3, and a viewing angle set between 83.0 degrees and 70.0 degrees and HU Aqr a magnetic field between 36.0 MG and 37.6 MG, a plasma temperature between 15.0 keV and 15.5 keV, a log ? of 4.0 ± 0.3, and a viewing angle between 89.5 degrees and 70.5 degrees. This was the first attempt to model MN Hya with a constant lambda code and the first harmonic motion model of HU Aqr.

Dealaman, Shannon J.

2010-01-01

218

Loss cone-driven cyclotron maser instability  

NASA Astrophysics Data System (ADS)

The weakly (or mildly) relativistic cyclotron maser instability has been successfully applied to explain the Earth's auroral kilometric radiation and other radio sources in nature and laboratory. Among the most important physical parameters that determine the instability criteria is the ratio of plasma-to-electron cyclotron frequencies, ?p/?. It is therefore instructive to consider how the normalized maximum growth rate, ?max/?, varies as a function of ?p/?. Although many authors have already discussed this problem, in order to complete the analysis, one must also understand how the radiation emission angle corresponding to the maximum growth, ?max, scales with ?p/?, since the propagation angle determines the radiation beaming pattern. Also, the behavior of the frequency corresponding to the maximum growth rate at each harmonic, (?max-s?)/?, where s=1,2,3,? , as a function of ?p/?is of importance for a complete understanding of the maser excitation. The present paper computes these additional quantities for the first time, making use of a model loss cone electron distribution function.

Lee, Sang-Yun; Yi, Sibaek; Lim, Dayeh; Kim, Hee-Eun; Seough, Jungjoon; Yoon, Peter H.

2013-11-01

219

Cyclotron Resonances in Electron Cloud Dynamics  

SciTech Connect

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

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

2009-05-05

220

Cyclotron Resonances in Electron Cloud Dynamics  

SciTech Connect

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

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

2009-04-29

221

Ion Cyclotron Waves in the VASIMR  

NASA Astrophysics Data System (ADS)

The Variable Specific Impulse Magnetoplasma Rocket 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 the plasma through the resonance region. The plasma is generated by a helicon discharge of about 25 kW then passes through an RF booster stage that shoots left hand polarized slow mode waves from the high field side of the resonance. This paper will focus on the upgrades to the VX-200 test model over the last year. After summarizing the VX- 50 and VX-100 results, the new data from the VX-200 model will be presented. Lastly, the changes to the VASIMR experiment due to Ad Astra Rocket Company's new facility in Webster, Texas will also be discussed, including the possibility of collaborative experiments at the new facility.

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

2008-12-01

222

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

PubMed

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

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

2013-11-01

223

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

224

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

225

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.

226

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.

227

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

NASA Astrophysics Data System (ADS)

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

Krasilnikov, A. V.; van Eester, D.; Lerche, E.; Ongena, J.; Mailloux, J.; Stamp, M.; Jachmich, S.; Leggate, H.; Vdovin, V.; Walden, A.; Mayoral, M.-L.; Bonheure, G.; Santala, M.; Kiptily, V.; Popovichev, S.; Biewer, T.; Crombe, K.; Esposito, B.; Marocco, D.; Riva, M.; Kaschuck, Yu. A.; Amosov, V. N.; Ericsson, G.; Giacomelli, L.; Hellesen, C.; Hjalmarsson, A.; Kallne, J.

2007-09-01

228

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

SciTech Connect

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

Krasilnikov, A. V.; Kaschuck, Yu. A.; Amosov, V. N. [SRC RF Troitsk Institute for Innovating and Fusion Research, Troitsk (Russian Federation); Van Eester, D.; Lerche, E. [Laboratory for Plasma Physics--ERM/KMS, TEC partner, Brussels (Belgium); Ongena, J.; Bonheure, G. [Laboratory for Plasma Physics--ERM/KMS, TEC partner, Brussels (Belgium); Euratom-UKAEA Fus. Assoc., Culham Science Center (United Kingdom); Mailloux, J.; Stamp, M.; Jachmich, S.; Leggate, H.; Walden, A.; Mayoral, M.-L.; Santala, M.; Kiptily, V.; Popovichev, S. [Euratom-UKAEA Fus. Assoc., Culham Science Center (United Kingdom); Vdovin, V. [RNC Kurchatov Institute, Nuclear Fusion Institute, Moscow (Russian Federation); Biewer, T. [Euratom-UKAEA Fus. Assoc., Culham Science Center (United Kingdom); Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Crombe, K. [Euratom-UKAEA Fus. Assoc., Culham Science Center (United Kingdom); Department of Applied Physics, Ghent University, Gent (Belgium); Esposito, B. [ENEA, Frascati (Italy)] (and others)

2007-09-28

229

Assessment of quality of life in small-cell lung cancer using a Daily Diary Card developed by the Medical Research Council Lung Cancer Working Party  

Microsoft Academic Search

Three hundred and sixty-nine patients in an MRC study of combination chemotherapy and radiotherapy for small-cell lung cancer of limited extent were asked to complete a Daily Diary Card which enabled an assessment of their quality of life to be made during and after treatment. The information derived from the card suggests that although cytotoxic chemotherapy has an adverse effect

PM Fayers; NM Bleehen; DJ Girling; RJ Stephens

1991-01-01

230

A fibre-optic displacement sensor for a cyclotron environment based on a modified triangulation method  

Microsoft Academic Search

Due to the very high magnetic and radio frequency fields and generally hostile environment inside cyclotrons, electronic devices are hindered from functioning. By implementing a modified triangulation method we developed a purely dielectric PC interfaced sensor head, which will be placed inside the cyclotron for electrode-position measurement. This represents a completely new cyclotron diagnostic tool designed to cope with cyclotron

Jovan Elazar; Sandra Selmic; Milos Tomic; Milan Prokin

2002-01-01

231

Cyclotron maser using the anomalous Doppler effect  

NASA Astrophysics Data System (ADS)

The operation of an anomalous-Doppler-effect cyclotron-resonance maser using a waveguide partially filled with dielectric as the slow-wave system is reported. The device investigated is similar to that of Didenko et al. (1983) and comprises a 300-mm-long 50-mm-o.d. 30-mm-i.d. waveguide with fabric-laminate dielectric, located 150 mm from the cathode in a 500-mm-long region of uniform 0-20-kG magnetic field, and a coaxial magnetic-insulation gun producing a 13-mm-i.d. 25-mm-o.d. hollow electron beam. Radiation at 12 + or - 1 mm wavelength and optimum power 20 MW is observed using hot-carrier detectors, with a clear peak in the power-versus-magnetic-field curve at about 6.4 kG.

Didenko, A. N.; Borisov, A. R.; Fomenko, G. P.; Shlapakovskii, A. S.; Shtein, Iu. G.

1983-11-01

232

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

233

Particle acceleration by electromagnetic ion cyclotron turbulence  

NASA Technical Reports Server (NTRS)

The LF EM-turbulence which furnishes energy for the acceleration of ions in various regions of the earth's magnetosphere efficiently accomplishes its transfer of energy from waves to particles through ion cyclotron resonance (ICR) with the left-hand polarized component of the turbulence; the result of this interaction is a heating of the particle distribution. A general theoretical treatment of ICR heating in a weakly inhomogeneous magnetic geometry is presented, en route to a more detailed examination of auroral ion conics' formation. A substantial simplification of the analysis of the altitude-asymptotic form of the conic distribution is obtained via the similarity transformation introduced into the properties of the electric field spectral density and the earth's dipolar magnetic field.

Crew, G. B.; Chang, Tom

1990-01-01

234

Folded waveguide coupler for ion cyclotron heating  

SciTech Connect

A new type of waveguide coupler for plasma heating in the ion cyclotron range of frequencies is described. The coupler consists of a series of interleaved metallic vanes within a rectangular enclosure analogous to a wide rectangular waveguide that has been ''folded'' several times. At the mouth of the coupler, a plate is attached which contains coupling apertures in each fold or every other fold of the waveguide, depending upon the wavenumber spectrum desired. This plate serves primarily as a wave field polarizer that converts coupler fields to the polarization of the fast magnetosonic wave within the plasma. Theoretical estimates indicate that the folded waveguide is capable of high-efficiency, multimegawatt operation into a plasma. Bench tests have verified the predicted field structure within the waveguide in preparation for high-power tests on the Radio Frequency Test Facility at the Oak Ridge National Laboratory.

Owens, T.L.; Chen, G.L.

1986-01-01

235

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

236

Electron Cyclotron Heating in RFP plasmas  

NASA Astrophysics Data System (ADS)

Reversed field pinches (RFP) plasmas are typically overdense (?pe>?ce) and thus not suitable for conventional electron cyclotron (EC) heating and current drive. In recent high plasma current discharges (Ip>1.5 MA), however, the RFX-mod device was operated in underdense conditions (?pe

Bilato, R.; Volpe, F.; Poli, E.; Köhn, A.; Cavazzana, R.; Paccagnella, R.; Farina, D.

2009-11-01

237

High-resolution ion cyclotron mobility spectrometry.  

PubMed

A novel ion mobility spectrometry instrument incorporating a cyclotron geometry drift tube is presented. The drift tube consists of eight regions, four curved drift tubes and four ion funnels. Packets of ions are propagated around the drift tube by changing the drift field at a frequency that is resonant with the ion's drift time through each region. The approach trims each packet of ions as it leaves and enters each new region. An electrostatic gate allows ions to be kept in the drift tube for numerous cycles, increasing the ability to resolve specified ions. We demonstrate the approach by isolating the [M + 2H](2+) or [M + 3H](3+) charge state of substance P as well as individual trisaccharide isomers from a mixture of melezitose and raffinose. Resolving powers in excess of 300 are obtainable with this approach. PMID:19143495

Merenbloom, Samuel I; Glaskin, Rebecca S; Henson, Zachary B; Clemmer, David E

2009-02-15

238

High-Resolution Ion Cyclotron Mobility Spectrometry  

PubMed Central

A novel ion mobility spectrometry instrument incorporating a cyclotron geometry drift tube is presented. The drift tube consists of eight regions, four curved drift tubes and four ion funnels. Packets of ions are propagated around the drift tube by changing the drift field at a frequency that is resonant with the ion’s drift time through each region. The approach trims each packet of ions as it leaves and enters each new region. An electrostatic gate allows ions to be kept in the drift tube for numerous cycles, increasing the ability to resolve specified ions. We demonstrate the approach by isolating the [M+2H]2+ or [M+3H]3+ charge state of substance P as well as individual trisaccharide isomers from a mixture of melezitose and raffinose. Resolving powers in excess of 300 are obtainable with this approach.

Merenbloom, Samuel I.; Glaskin, Rebecca S.; Henson, Zachary B.; Clemmer, David E.

2009-01-01

239

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

240

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

241

Local measurements of cyclotron states in graphene  

NASA Astrophysics Data System (ADS)

Graphene's unique massless electron behavior is observed in multilayer epitaxial graphene grown from SiC on the (0001¯) face. These fermions collapse into cyclotron orbits (Landau levels) when graphene is placed into a high magnetic field, B. The Landau levels are shown to follow a NB energy dependence, where N is the quantum number of the Landau level. Cryogenic ultra-high vacuum scanning tunneling microscopy (STM) and spectroscopy (STS) are performed to study the local behavior of these cyclotron states near defects. A new STS technique was designed where conductance measurements were performed while the magnetic field was changed. This technique allows for a direct measurement of the energy versus momentum relationship for graphene. These measurements produced results which indicate a local doping effect due to the STM tip. Techniques relying on degenerate perturbation theory for graphene states solved in the symmetric gauge are shown to reliably model these effects. This perturbation method allows for the study of local nanometer scale screening effects in graphene, and indicates that the local tip effect can be modeled as a defect potential. Measurements of Landau levels (LLs) will be shown to depend on the combined potential of the tip induced band bending (TIBB) potential and local defect potentials. In addition magnetically localized defect states are presented. These are not explained by TIBB. The defect states are argued to be Stark shifted in energy by TIBB, eventually crossing the Fermi energy, Ef. Once states cross Ef further doping effects from the tip are measured. This switch from hole to electron state is also shown to change the local potential of the system which indicates a direct charge state of the defect, which modifies the local density of states.

Kubista, Kevin Dean

242

Superconducting cyclotron and its vacuum system  

NASA Astrophysics Data System (ADS)

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

Sur, A.; Bhandari, R. K.

2008-05-01

243

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

244

Electron Cyclotron Emission Diagnostics in the Large Helical Device  

NASA Astrophysics Data System (ADS)

Electron cyclotron emission (ECE) diagnostics have been developed in the Large Helical Device (LHD). The ECE is transmitted from the antenna to the spectrometer for 80 m by means of a corrugated waveguide system, which has a small transmission loss (˜30%) in LHD. Although the field angle changes from -40 to +30 degrees on the sight-line of the ECE antenna, it has been observed that the polarization of ECE, which is determined at the plasma edge in LHD, is identical for all frequencies. Thus, the electron temperature profile can be measured using the second harmonic X-mode of ECE. The ECE measured by the Michelson is calibrated with a hot source in order to reduce noise. The ECE temperature measurement agrees well with the Thomson scattering measurement over a wide range of electron densities. The radiometer is cross-calibrated to the Michelson, and is employed for the study of fast phenomena such as internal transport barrier (ITB) formation. Tangentially emitted ECE, in addition to the normal ECE, is investigated in LHD in order to explore the potential of ECE diagnostics.

Nagayama, Yoshio; Kawahata, Kazuo; Inagaki, Shigeru; Kubo, Shin; Narihara, Kazumichi; Ohyabu, Nobuyoshi; LHD Group

245

Nonlinear wave-particle interactions at cyclotron harmonic frequencies  

SciTech Connect

Waves with frequencies near multiples of the gyrofrequency are commonly employed to heat plasmas to high temperatures in magnetically confined fusion experiments. When particle orbits are trapped very near a cyclotron harmonic resonance, the quasilinear concept of weakly perturbed, uncorrelated passages through resonance breaks down, and nonlinear effects become important. Numerical as well as analytic studies demonstrate that relativistic detuning of the resonance can be important for electrons even at low initial energies (approx. 20 eV). Also, coupling to perturbed parallel motion can lead to strong interactions for turning points where the wave frequency differs from a harmonic multiple of the bounce averaged gyrofrequency by an integral multiple, m, of the bounce frequency. The resultant motion is described by large periodic energy excursions for which small angle Coulomb collisions or other randomization processes, are required to realize net heating. Analytic formulae are derived that describe the energy excursion behavior in a parabolic magnetic well in terms of an effective potential and two constants of motion: the Hamiltonian and a parallel action. A Fokker-Planck heating model is developed for diffusive decorrelation of the energy excursions, and Fokker-Planck coefficients are generated. This model demonstrates that the nonlinear heating is a function of the decorrelation mechanism.

Carter, M.D.

1985-01-01

246

Cyclotron resonance in undoped, top-gated heterostructures  

NASA Astrophysics Data System (ADS)

We report on cyclotron resonance detected by far-infrared photoconductivity of the two-dimensional electron gas formed in undoped, top-gated GaAs/Al0.3Ga0.7As heterostructures. The photoconductivity method demonstrated here is readily extendable to quantum wires. The top-gated device architecture avoids the disorder inherent in conventional modulation-doped devices and allows precise in situ tuning of carrier density over two orders of magnitude. We observe very sharp resonances (6 mT at 1.5 K) indicating a very high mobility, which is attributed to the low level of impurities. The variation of the linewidth at small filling factor is also consistent with a low concentration of impurities. These results suggest that the filling-factor-dependent oscillations observed in linewidth are not due to the screening of ionized impurities. Filling-factor-dependent oscillations in photoconductivity intensity are also observed, with maxima occurring at even filling factors.

Heron, R. J.; Lewis, R. A.; Clark, R. G.; Starrett, R. P.; Kane, B. E.; Facer, G. R.; Lumpkin, N. E.; Rickel, D. G.; Pfeiffer, L. N.; West, K. W.

2000-06-01

247

Currents induced in tokamaks by electron cyclotron heating  

SciTech Connect

Generation of a plasma current is predicted in association with strong electron cyclotron heating in tokamaks or in any plasma with transverse magnetic field gradients. The current predicted in present-day tokamaks is of the order of one-quarter ampere per watt, which is large enough to be detected in heating experiments in progress. The current scales linearly with electron temperature and heating power and inversely with density and major radius. The mechanism depends on the Doppler shift for electrons streaming along magnetic field lines. Electrons streaming toward the source of radiation are resonant at a larger magnetic field. When the interaction is strong, radiation incident from the high field side is absorbed before reaching the cold electron resonant surface, and, so, a unidirectional population of electrons is heated. The anisotropic electron distribution gains momentum by collisions with ions. For small tokamaks the extraordinary wave should be launched for current drive, but for reactors the ordinary wave produces a sufficiently strong interaction.

Eldridge, O. C.

1980-10-01

248

Reduction of axial kinetic energy induced perturbations on observed cyclotron frequency  

Microsoft Academic Search

With Fourier transform ion cyclotron resonance (FTICR) mass spectrometry one determines the mass-to-charge ratio of an ion\\u000a by measuring its cyclotron frequency. However, the need to confine ions to the trapping region of the ion cyclotron resonance\\u000a (ICR) cell with electric fields induces deviations from the unperturbed cyclotron frequency. Additional perturbations to the\\u000a observed cyclotron frequency are often attributed to

Nathan K. Kaiser; Chad R. Weisbrod; Brian N. Webb; James E. Bruce

2008-01-01

249

Ion source and injection line for high intensity medical cyclotrona)  

NASA Astrophysics Data System (ADS)

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

2014-02-01

250

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

PubMed

An electron cyclotron emission (ECE) receiver inside the electron cyclotron resonance heating (ECRH) transmission line has been brought into operation. The ECE is extracted by placing a quartz plate acting as a Fabry-Perot interferometer under an angle inside the electron cyclotron wave (ECW) beam. ECE measurements are obtained during high power ECRH operation. This demonstrates the successful operation of the diagnostic and, in particular, a sufficient suppression of the gyrotron component preventing it from interfering with ECE measurements. When integrated into a feedback system for the control of plasma instabilities this line-of-sight ECE diagnostic removes the need to localize the instabilities in absolute coordinates. PMID:19044409

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

2008-09-01

251

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

252

Theoretical modeling of drift cyclotron loss-cone instability mode structures  

SciTech Connect

Measurements of the drift cyclotron loss-cone instability mode structure have recently been performed on MIX (Phys. Fluids 29, 3439 (1986)), an axisymmetric mirror machine characterized by a small width Maxwellian cold stream and a larger width loss-cone plasma. To model these measurements the Fourier-space integral equation was solved, derived from the linearized Vlasov equation for electrostatic perturbations, with both a matrix version technique and a WKB approximation. It is found that the mode is prohibited from the cold stream region by the process of mode conversion, which explains experimental results quite well.

Burkhart, G.R.; Guzdar, P.N.; Koepke, M.E.

1989-03-01

253

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

SciTech Connect

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

Hartnoll, Sean A. [KITP, University of California, Santa Barbara, California 93106-4030 (United States); Herzog, Christopher P. [Physics Department, University of Washington, Seattle, Washington 98195-1560 (United States)

2007-11-15

254

Azimuthally Symmetric Radial Resonance near the Cyclotron Frequency in a Non-Neutral Ion Plasma  

NASA Astrophysics Data System (ADS)

An experiment designed to measure radial m=0 plasma resonances near the cyclotron frequency in a boron ion plasma will be described. Plasmas are captured in a Malmberg-Penning trap with an axially symmetric magnetic field of nominally .22 Tesla. Captured plasmas generally measure 6-8 centimeters along the axis with 2 centimeter radii. Modes are exited through small AC perturbations on the confinement rings. Due to the short length of the plasma, the modes can be measured utilizing finite length effects of short cylindrical plasmas. The current status of the experiment will be discussed.

Hall, William; Peterson, Bryan

2011-11-01

255

Flat-top system of the DC-280 cyclotron  

NASA Astrophysics Data System (ADS)

The flat-top cavity of the radio-frequency accelerating system designed at the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, for the DC-280 cyclotron is described. The cyclotron is intended for increasing the capabilities and efficiency of experiments on the synthesis of super-heavy elements and an investigation of their nuclear physical and chemical properties. The DC-280 isochronous heavy-ion cyclotron will produce accelerated beam of ions in the range from neon to uranium. The parameters, design, and results of the experimental and 3D computer modeling of the flat-top cavity of the RF accelerating system of the DC-280 cyclotron are reported.

Gulbekyan, G. G.; Buzmakov, V. A.; Zarubin, V. B.; Ivanenko, I. A.; Kazarinov, N. Yu.; Karamysheva, G. A.; Franko, I.

2013-07-01

256

Some calculations of the resonator in INR cyclotron  

SciTech Connect

Some calculation methods of the resonator parameters with single dee and two coaxial transmission lines in INR variable-energy cyclotron were described. Also calculated and experimental results have been compared with the original one (two dee system).

Zhang, J.; Liu, X.L.

1985-10-01

257

Wave Propagation Across Ion Cyclotron Resonance Harmonic Layers.  

National Technical Information Service (NTIS)

Wave propagation across ion cyclotron resonance layers is investigated by use of a boundary layer analysis for a perpendicularly stratified, weakly inhomogeneous plasma. Corresponding to the situation in many plasmas of interest, it is assumed that the wa...

K. Imre H. Weitzner

1987-01-01

258

6D Muon Ionization Cooling with an Inverse Cyclotron  

SciTech Connect

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

Summers, D. J.; Bracker, S. B.; Cremaldi, L. M.; Godang, R. [Dept. of Physics and Astronomy, University of Mississippi-Oxford, University, MS 38677 (United States); Palmer, R. B. [Brookhaven National Laboratory, Upton, NY 11973 (United States)

2006-03-20

259

Cyclotrons for clinical and biomedical research with PET  

SciTech Connect

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

Wolf, A.P.

1987-01-01

260

Cyclotron radiation by a multi-group method  

SciTech Connect

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

Chu, T.C.

1980-01-01

261

Ion-Beam-Driven Electrostatic Ion Cyclotron Instabilities.  

National Technical Information Service (NTIS)

We present results of numerical simulations on the electrostatic ion cyclotron instabilities driven by the ion beam parallel to the magnetic field. For the beam speed exceeding the thermal speed of background ions and the beam temperature much lower than ...

A. Miura H. Okuda M. Ashour-Abdalla

1982-01-01

262

Ion-Beam-Driven Resonant Ion Cyclotron Instability.  

National Technical Information Service (NTIS)

The resonant ion-beam-driven electrostatic ion cyclotron instability is identified. Measured dispersion relation and onset vs. beam energy and density agree with numerical calculations based on a theory which includes beam acoustic terms. After amplitude ...

H. W. Hendel M. Yamada S. W. Seiler H. Ikezi

1975-01-01

263

Electron Cyclotron Resonance in a Penning Ion Source  

Microsoft Academic Search

Electron cyclotron resonance was detected in a Penning source by measuring the electron temperature as obtained from the x-ray emission spectrum. The resonance is only present if flat cathodes are used.

G. Fuchs; J. Steyaert; D. J. Clark

1972-01-01

264

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

265

Medical Illustration  

MedlinePLUS

... demanding and time-honored method of visual communication. Job description Through the medical graphics they create, medical illustrators ... in preparing prosthetics for patients or in preparing models for instructional purposes. In addition to the production ...

266

Medical Transcriptionists  

MedlinePLUS

... have an understanding of medical terminology, anatomy and physiology, grammar, and word-processing software. Pay The median ... must become familiar with medical terminology, anatomy and physiology, diagnostic procedures, pharmacology, and treatment assessments. Their ability ...

267

Medication Errors  

MedlinePLUS

... Design Control Reviewers - Medical Device Use-Safety: Incorporating Human Factors Engineering into Risk Management (PDF - 1.1MB) Draft ... Industry and Food and Drug Administration Staff - Applying Human Factors and Usability Engineering to Optimize Medical Device Design - ? - ...

268

Excitation of helium cyclotron harmonic waves during quiet magnetic conditions  

Microsoft Academic Search

A general approach to the generation of ion cyclotron harmonic waves observed on board the Akebono satellite in the deep plasmasphere is presented. It is shown that during quiet magnetic conditions the development of the hydrodynamic cyclotron instability with growth rate gamma~ni1\\/2, where ni is the number density of the hot heavy ions, is suppressed by the field-aligned inhomogeneity of

O. A. Pokhotelov; D. O. Pokhotelov; F. Z. Feygin; M. Parrot; J. Kangas; K. Mursula; P. K. Shukla; L. Stenflo

1998-01-01

269

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

270

Production of radioisotopes in the ORNL 86-inch cyclotron  

Microsoft Academic Search

The radioisotope production facilities and programs of the 86-Inch Cyclotron are reviewed in this presentation. The 86-Inch Cyclotron is designed to accelerate protons to a maximum energy of 22 MeV for internal targets. These protons are used to bombard metals that are electroplated, potted or soldered to water-cooled plates. Additionally, metals and inorganic compounds are bombarded in water-cooled tube targets.

J. W. Terry

1981-01-01

271

Modelling magnetars' high energy emission through Resonant Cyclotron Scattering  

Microsoft Academic Search

We present a systematic fit of a model of resonant cyclotron scattering (RCS) to the X and soft gamma-ray data of four magnetars, including anomalous X-ray pulsars, and soft gamma repeaters. In this scenario, non-thermal magnetar spectra in the soft X-rays result from resonant cyclotron scattering of the thermal surface emission by hot magnetospheric plasma. We find that this model

D. Gotz; N. Rea; S. Zane; R. Turolla; M. Lyutikov

2009-01-01

272

Dispersion of the Composite-Fermion Cyclotron-Resonance Mode  

Microsoft Academic Search

The dispersion of the composite-fermion cyclotron-resonance mode is measured with an optical detection scheme under the combined excitation of microwave radiation and a surface acoustic wave from an interdigital transducer. The slowly traveling surface wave defines the transferred wave vector. Momenta up to 108m-1 are accessible. The cyclotron-resonance mode exhibits strong negative dispersion, which suggests predominant short range residual interaction

I. V. Kukushkin; J. H. Smet; D. Schuh; W. Wegscheider; K. von Klitzing

2007-01-01

273

Nonlinear ion-cyclotron waves in mirror machines  

Microsoft Academic Search

Experimental results on ion cyclotron waves observed in the 2XIIB mirror machine are reviewed, and relevant theoretical work is discussed. The work reported generally substantiates the quasilinear diffusion model of mirror plasma confinement, but also suggests alternatives. The end loss current required by theory of the drift-cyclotron loss-cone (DCLD) instability agrees with measurements of this current. The experiment indicates that

B. I. Cohen; G. R. Smith; H. L. Berk; J. A. Byers; J. F. Clauser; D. L. Correll; A. H. Futch; R. K. Goodman; D. P. Grubb; L. L. Lodestro

1980-01-01

274

A new injector for the ISL-cyclotron at HMI  

Microsoft Academic Search

Injectors for cyclotrons must provide low emittance beams with variable energy and bunch repetition frequency. We are building a new RFQ-injector for the ISL-heavy ion cyclotron at HMI in Berlin replacing the 8UD Tandem injector. An ECR source, together with two closely coupled VE-RFQs, will provide beams between 91 keV\\/u and 355 keV\\/u. The layout of the injector, the design

A. Schempp

1997-01-01

275

FY90 milestone report for the CIT (Compact Ignition Tokamak) project: Localizability of electron-cyclotron heating power  

Microsoft Academic Search

Estimates of the localizability of electron-cyclotron heating power are made for the Compact Ignition Tokamak. A particular heating scenario is examined, namely, the fundamental O-mode, injected nearly perpendicular to the toroidal magnetic field. The absorption depth due to finite T{sub e} is very small, about 1 cm, near the q = 2 surface. Absorption is even better localized near q

1990-01-01

276

Application of a rotating bioreactor consisting of low-cost and ready-to-use medical disposables for in vitro evaluation of the endothelialization efficiency of small-caliber vascular prostheses.  

PubMed

The incomplete endothelialization of especially small-caliber vascular prostheses after implantation in patients is a major disadvantage in cardiovascular interventions. The lack of an endothelium leads to the occurrence of thrombosis at the luminal surface of artificial vascular prostheses. Thus, the development of new graft materials and coatings for induction of complete endothelialization on the implant surfaces is a promising approach to improve hemocompatibility and maintain long-term graft patency. In this study, we designed a rotation model to evaluate the early endothelial cell (EC) seeding efficiency of different small-caliber vascular devices, such as stents and vascular grafts. The suitability of the designed rotation model for endothelialization studies was investigated by seeding and cultivation of prostheses with ECs followed by scanning electron microscopy. Furthermore, the viability of attached ECs was determined by calcein acetoxymethyl ester (AM) staining. The rotation model consisting of low-cost medical disposables enabled sterile incubation and cultivation of ECs with vascular devices. Simultaneously, the rotation of the bioreactor ensured a uniform distribution and adhesion of cells to the devices. Calcein AM staining of adherent cells on prostheses revealed excellent cell viability. Moreover, using the designed rotation model, an influence of different coatings and materials on the adhesion and spreading of ECs was demonstrated. The rotating bioreactor described and used in this study not only saves time and money but is also eminently useful for the accelerated preclinical evaluation of the endothelialization efficiency of different materials and surface coatings of small-caliber vascular devices. PMID:23653116

Avci-Adali, Meltem; Kobba, Joseph; Neumann, Bernd; Lescan, Mario; Perle, Nadja; Wilhelm, Nadja; Wiedmaier, Hartmut; Schlensak, Christian; Wendel, Hans Peter

2013-08-01

277

Relativistic backward-wave oscillators operating near cyclotron resonance  

SciTech Connect

Microwave sources based on backward-wave oscillators (BWO's) driven by relativistic electron beams are capable of producing high-power coherent radiation in the cm and mm wavelength region. When the axial magnetic field used in these devices to confine the electron beam satisfies the condition of cyclotron resonance there is a significant modification in the behavior of BWO due to beam coupling to cyclotron modes. In this paper a time-dependent, self-consistent theory of BWO's is developed, taking into account a possible cyclotron interaction. The analysis of the system near the cyclotron resonance yields the power drop due to the cyclotron absorption effect observed in many BWO experiments. In addition, the theory predicts that there exists a region of magnetic field strength, where an increase in power and efficiency is possible. Depending on the value of the magnetic field and beam coupling to cyclotron mode various regimes of BWO operation are possible, including stable single-frequency oscillations, self-modulation, and a succession of microwave bursts.

Vlasov, A.; Nusinovich, G.; Levush, B.; Bromborsky, A.; Lou, W.; Carmel, Y. (Laboratory for Plasma Research, University of Maryland, College Park, Maryland 20742-3511 (United States))

1993-05-01

278

Proton cyclotron echoes at the ƒQ3 resonance  

NASA Astrophysics Data System (ADS)

We report here new observations on topside sounder ionograms from the Canadian ISIS II satellite of proton cyclotron echoes associated with the ƒQ3 resonance. Proton cyclotron echoes were first observed on swept frequency ionograms from the Canadian Alouette II satellite. The echoes occur on the ionograms at nearly constant apparent ranges which correspond to the proton cyclotron period at the satellite. The echoes were first found to be associated with the fundamental resonance of the electron cyclotron frequency, ƒH, and later reported at the 3ƒH and 4ƒH resonances. The new observations were made on ionograms when the satellite was located in regions with low dip angles less than 8°. This paper will present and discuss the features of these new proton cyclotron echoes, such as the presence often of two echo images, and possible generation mechanisms. A comparison with various ray-tracing calculations by Muldrew (1972a, b) suggests that these proton cyclotron echoes may occur when the particular waves responsible for the ƒQ3, 3ƒH and 4ƒH resonances interact with protons energized by the satellite antenna.

Horita, R. E.; Chen, G. M.

1995-09-01

279

Acceleration of H^- ions for the Cyclotron Institute Upgrade Project  

NASA Astrophysics Data System (ADS)

The Cyclotron Institute at Texas A&M University is undergoing an upgrade that will allow for the production of radioactive ions for nuclear physics experiments. These ions will be produced with one of two ion guides, then collected, charge boosted and reaccelerated in the K500 cyclotron. The first radioactive ion beam for the project will be ^27Si (T1/2=4.16s) at 15 MeV/u and will be produced through the reaction ^27Al(p,n)^27Si with 30 MeV protons. The recently recommissioned K150 cyclotron will accelerate the proton beams to intensity as high as 20 ?A in order to produce sufficient amounts of radioactive ions. Rather than using an electrostatic deflector to extract the proton beam from the cyclotron, H^- ions will be introduced into the cyclotron, accelerated to 30 MeV and then stripped to protons with a thin carbon foil at extraction. First tests show the extraction efficiency to be nearly 100% and that the technique greatly reduces interior activation of the cyclotron and problems from secondary radiation. The H^- ion source, injection scheme and results from first tests will be presented.

Olvera, Juan; Clark, Henry

2010-10-01

280

Analytic representation of cyclotron magnetic field  

NASA Astrophysics Data System (ADS)

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(z) in the horizontal plane of symmetry.

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

1994-07-01

281

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

282

Electron cyclotron emission diagnostic for ITER  

SciTech Connect

Electron temperature measurements and electron thermal transport inferences will be critical to the nonactive and deuterium phases of ITER operation and will take on added importance during the alpha heating phase. The diagnostic must meet stringent criteria on spatial coverage and spatial resolution during full field operation. During the early phases of operation, it must operate equally well at half field. The key to the diagnostic is the front end design. It consists of a quasioptical antenna and a pair of calibration sources. The radial resolution of the diagnostic is less than 0.06 m. The spatial coverage extends at least from the core to the separatrix with first harmonic O-mode being used for the core and second harmonic X-mode being used for the pedestal. The instrumentation used for the core measurement at full field can be used for detection at half field by changing the detected polarization. Intermediate fields are accessible. The electron cyclotron emission systems require in situ calibration, which is provided by a novel hot calibration source. The critical component for the hot calibration source, the emissive surface, has been successfully tested. A prototype hot calibration source has been designed, making use of extensive thermal and mechanical modeling.

Rowan, W.; Austin, M.; Phillips, P. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States); Beno, J.; Ouroua, A. [Center for Electromechanics, University of Texas at Austin, Austin, Texas 78758 (United States); Ellis, R. [University of Maryland, College Park, Maryland 20742 (United States); Feder, R.; Patel, A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

2010-10-15

283

Electron cyclotron emission diagnostic for ITER.  

PubMed

Electron temperature measurements and electron thermal transport inferences will be critical to the nonactive and deuterium phases of ITER operation and will take on added importance during the alpha heating phase. The diagnostic must meet stringent criteria on spatial coverage and spatial resolution during full field operation. During the early phases of operation, it must operate equally well at half field. The key to the diagnostic is the front end design. It consists of a quasioptical antenna and a pair of calibration sources. The radial resolution of the diagnostic is less than 0.06 m. The spatial coverage extends at least from the core to the separatrix with first harmonic O-mode being used for the core and second harmonic X-mode being used for the pedestal. The instrumentation used for the core measurement at full field can be used for detection at half field by changing the detected polarization. Intermediate fields are accessible. The electron cyclotron emission systems require in situ calibration, which is provided by a novel hot calibration source. The critical component for the hot calibration source, the emissive surface, has been successfully tested. A prototype hot calibration source has been designed, making use of extensive thermal and mechanical modeling. PMID:21033963

Rowan, W; Austin, M; Beno, J; Ellis, R; Feder, R; Ouroua, A; Patel, A; Phillips, P

2010-10-01

284

Fourier transform ion cyclotron resonance mass spectrometry  

NASA Astrophysics Data System (ADS)

As for Fourier transform infrared (FT-IR) interferometry and nuclear magnetic resonance (NMR) spectroscopy, the introduction of pulsed Fourier transform techniques revolutionized ion cyclotron resonance mass spectrometry: increased speed (factor of 10,000), increased sensitivity (factor of 100), increased mass resolution (factor of 10,000-an improvement not shared by the introduction of FT techniques to IR or NMR spectroscopy), increased mass range (factor of 500), and automated operation. FT-ICR mass spectrometry is the most versatile technique for unscrambling and quantifying ion-molecule reaction kinetics and equilibria in the absence of solvent (i.e., the gas phase). In addition, FT-ICR MS has the following analytically important features: speed (~1 second per spectrum); ultrahigh mass resolution and ultrahigh mass accuracy for analysis of mixtures and polymers; attomole sensitivity; MSn with one spectrometer, including two-dimensional FT/FT-ICR/MS; positive and/or negative ions; multiple ion sources (especially MALDI and electrospray); biomolecular molecular weight and sequencing; LC/MS; and single-molecule detection up to 108 Dalton. Here, some basic features and recent developments of FT-ICR mass spectrometry are reviewed, with applications ranging from crude oil to molecular biology.

Marshall, Alan G.

1998-06-01

285

Electromagnetic proton cyclotron instability: Proton velocity distributions  

NASA Astrophysics Data System (ADS)

The hot (Th~10 keV) protons of the outer magnetosphere are frequently observed to have T?/T?>1, where the subscripts denote directions relative to the background magnetic field. This anisotropy leads to the growth of the electromagnetic proton cyclotron anisotropy instability, which implies two concise scaling relations: an upper bound on T?h/T?h and an expression for the apparent temperature of warm (Tw~10 eV) protons heated by this instability. One-dimensional hybrid simulations of this instability in a homogeneous plasma have been used to examine the velocity distribution response of both hot and warm protons. Results are that the enhanced fluctuations from this instability not only preserve the initially bi-Maxwellian character of a hot proton distribution but also drive a hot distribution which is initially nongyrotropic rapidly toward the gyrotropic condition. These results further support the validity of the hot proton temperature anisotropy upper bound. Although wave-particle interactions yield nongyrotropic fw(v?) distributions, the fw(v?) remain Maxwellian-like as they are heated by the enhanced fluctuations.

Gary, S. Peter; Vazquez, Victor M.; Winske, Dan

1996-06-01

286

Target telemetry in medical isotope production  

Microsoft Academic Search

Positron emission tomography reveals the biochemical basis underlying many disease processes. The key step is the labeling of authentic metabolic substrates, generally starting with precursor compounds of the short-lived radionuclides 11C, 13N, 15O and 18F. These, in turn, are produced on accelerators, with small cyclotrons now appearing in hospitals. The success of maintaining a reliable source of imaging agents in

R. J. Nickles; J. R. Votaw; G. D. Hutchins; M. S. Rosenthal; K. M. Funk; J. J. Sunderland; M. R. Satter

1985-01-01

287

Managing the Navy's Infectious Medical Waste.  

National Technical Information Service (NTIS)

The Navy generates infectious medical waste in treatment facilities ranging from large hospitals in excess of 1,000 beds, to small outpatient clinics. In addition, significant amounts of medical waste are generated by ships. Current management of waste in...

P. J. Hamilton

1992-01-01

288

One-dimensional modeling of transport in small stellarators  

Microsoft Academic Search

An existing stellarator reactor transport code was modified to model small stellarator experiments. Changes were made in the treatment of neutrals, the atomic physics process, and the transport models. The authors investigated the extent to which the hollow density profiles experimentally detected during electron cyclotron resonance heating (ECRH) experiments in the interchangeable module stellarator (IMS), a small modular stellarator, can

K. J. S. Mertens; W. N. G. Hitchon; D. T. Anderson; J. L. Shohet

1988-01-01

289

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

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

290

Twelve Million Resolving Power on 4.7 T Fourier Transform Ion Cyclotron Resonance Instrument with Dynamically Harmonized Cell—Observation of Fine Structure in Peptide Mass Spectra  

NASA Astrophysics Data System (ADS)

Resolving power of about 12,000 000 at m/z 675 has been achieved on low field homogeneity 4.7 T magnet using a dynamically harmonized Fourier transform ion cyclotron resonance (FT ICR) cell. Mass spectra of the fine structure of the isotopic distribution of a peptide were obtained and strong discrimination of small intensity peaks was observed in case of resonance excitation of the ions of the whole isotopic cluster to the same cyclotron radius. The absence of some peaks from the mass spectra of the fine structure was explained basing on results of computer simulations showing strong ion cloud interactions, which cause the coalescence of peaks with m/z close to that of the highest magnitude peak. The way to prevent peak discrimination is to excite ion clouds of different m/z to different cyclotron radii, which was demonstrated and investigated both experimentally and by computer simulations.

Popov, Igor A.; Nagornov, Konstantin; Vladimirov, Gleb N.; Kostyukevich, Yury I.; Nikolaev, Eugene N.

2014-05-01

291

Twelve million resolving power on 4.7 t fourier transform ion cyclotron resonance instrument with dynamically harmonized cell-observation of fine structure in Peptide mass spectra.  

PubMed

Resolving power of about 12,000 000 at m/z 675 has been achieved on low field homogeneity 4.7 T magnet using a dynamically harmonized Fourier transform ion cyclotron resonance (FT ICR) cell. Mass spectra of the fine structure of the isotopic distribution of a peptide were obtained and strong discrimination of small intensity peaks was observed in case of resonance excitation of the ions of the whole isotopic cluster to the same cyclotron radius. The absence of some peaks from the mass spectra of the fine structure was explained basing on results of computer simulations showing strong ion cloud interactions, which cause the coalescence of peaks with m/z close to that of the highest magnitude peak. The way to prevent peak discrimination is to excite ion clouds of different m/z to different cyclotron radii, which was demonstrated and investigated both experimentally and by computer simulations. PMID:24604470

Popov, Igor A; Nagornov, Konstantin; N Vladimirov, Gleb; Kostyukevich, Yury I; Nikolaev, Eugene N

2014-05-01

292

Incontinence Treatment: Medication  

MedlinePLUS

... do not typically relieve abdominal pain and may cause constipation. Laxatives A laxative is a medication that increases bowel function. There are four main classes of laxatives: fiber, osmotic ... absorbed compounds that cause an influx of water into the small intestine ...

293

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

294

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

295

Medical confidence.  

PubMed Central

If medical confidentiality is not observed patients may well be reluctant to disclose information to their doctors or even to seek medical advice. Therefore, argues the author, it is of the utmost importance that doctors strive to protect medical confidentiality, particularly now when it is under threat not only in this country but also overseas. The profession must cease to regard ethical issues to do with confidentiality, and indeed to do with all areas of medical practice, as abstract phenomena requiring no justification. If it does not then it will come under increasing and justified criticism from the community it serves.

Havard, J

1985-01-01

296

Electrostatic electron cyclotron harmonic instability near Ganymede  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

297

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.

298

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

299

Probing the hydrogen exosphere of Mars with ion cyclotron waves  

NASA Astrophysics Data System (ADS)

Ion cyclotron waves are generated during the interaction between the solar wind and the Martian exosphere. When the atmospheric neutrals are ionized in the solar wind, the fresh ions are accelerated by the electric field and gyrate around the magnetic field in the solar wind, in a process called ion pick-up. As the ions gyrate, ion cyclotron waves grow from the free energy of the highly anisotropic distribution of these fresh ions, with left-handed polarization and a wave frequency near the ion's gyro-frequency. Observations of the ion cyclotron waves enable us to study the atmospheric loss due to solar wind pick-up process. At Mars, the exospheric hydrogen is picked up by the solar wind and produces proton cyclotron waves. The Mars Global Surveyor detected proton cyclotron waves which extend from the magnetosheath of Mars to over 12 Mars radii with amplitudes that vary slowly with distance. A hybrid simulation is applied to study the wave generation and evolution due to solar wind pick-up to try to understand the relation between the wave energy and pickup rate. By comparing the wave observations and the hybrid simulation results, we hope to better understand the hydrogen exosphere configuration and the loss of water from Mars.

Wei, H. Y.; Cowee, M. M.; Russell, C. T.

2013-09-01

300

Emergency Medical Service (EMS): Rotorcraft Technology Workshop  

NASA Technical Reports Server (NTRS)

A lead organization on the national level should be designated to establish concepts, locations, and the number of shock trauma air medical services. Medical specialists desire a vehicle which incorporates advances in medical technology trends in health care. Key technology needs for the emergency medical services helicopter of the future include the riding quality of fixed wing aircraft (reduced noise and vibration), no tail rotor, small rotor, small rotor diameter, improved visibility, crashworthy vehicle, IFR capability, more affordability high reliability, fuel efficient, and specialized cabins to hold medical/diagnostic and communications equipment. Approaches to a national emergency medical service are discussed.

Bauchspies, J. S.; Adams, R. J.

1981-01-01

301

Medical Image and Information Processor.  

National Technical Information Service (NTIS)

Pulse Coupled Neural Networks (PCNN) have been extended and modified to suit medical image segmentation applications. Previous research demonstrated the ability of a PCNN to ignore noisy variations in intensity and small spatial discontinuities in images ...

M. Banish

1999-01-01

302

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

303

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

NASA Astrophysics Data System (ADS)

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

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

2011-07-01

304

Design of a focusing high-energy heavy ion microbeam system at the JAERI AVF cyclotron  

NASA Astrophysics Data System (ADS)

For bio-medical applications of single-ion hit techniques such as radio-microsurgery, a focused high-energy heavy ion microbeam was designed and installed as a vertical beam line connected to the AVF cyclotron ( K=110) facility at JAERI Takasaki. By extracting a heavy ion microbeam into atmosphere, living cells can be irradiated with an accuracy smaller than typical cellular sizes. In addition, a high-speed automatic targeting and single-ion irradiation system was combined with a two-dimensional microbeam scanning system allowing more than 1000 targets per minute to be hit within a set field of view. Such high speeds targeting is necessary when examining statistically significant trends in cell irradiation studies within feasible time constraints. A real-time single-ion hit position detecting system was also designed to further increase the reliability of such irradiations.

Oikawa, M.; Kamiya, T.; Fukuda, M.; Okumura, S.; Inoue, H.; Masuno, S.; Umemiya, S.; Oshiyama, Y.; Taira, Y.

2003-09-01

305

Electron Cyclotron Resonance Ion Sources for Highly-Charged Ion Beams  

SciTech Connect

Electron Cyclotron Resonance (ECR) ion sources are used for several different applications. Primarily they are used for the production of highly-charged ion beams for nuclear physics experiments but they are also used, for example, in medical applications and radiation-hardness tests of space electronics. Strong requests have been made from the nuclear physics community towards obtaining higher beam intensities and new exotic, even radioactive, ion beams. Due to the requirements more powerful ECR ion sources and new methods for the beam production are needed. In order to meet the beam intensity requirements several superconducting ion sources have recently been built or are under construction in Asia, Europe and the USA. The development work towards improvements in ion beam quality and the production of metal ion beams is also playing a crucial role. In this article a general overview concerning the ECR ion sources, their future and beam production will be given.

Koivisto, H. [Department of Physics, University of Jyvaeskylae, FIN-40014 University of Jyvaeskylae (Finland)

2009-03-10

306

Taking Medication  

MedlinePLUS Videos and Cool Tools

... or labels with you when you go to health appointments. Ask a family member to go to an appointment with you adn take notes so your not confused when you get home. Also, ask them to remind you to take your medications or labels when you go for any medical appointment.

307

Medication reviews  

PubMed Central

Recent years have seen a formalization of medication review by pharmacists in all settings of care. This article describes the different types of medication review provided in primary care in the UK National Health Service (NHS), summarizes the evidence of effectiveness and considers how such reviews might develop in the future. Medication review is, at heart, a diagnostic intervention which aims to identify problems for action by the prescriber, the clinican conducting the review, the patient or all three but can also be regarded as an educational intervention to support patient knowledge and adherence. There is good evidence that medication review improves process outcomes of prescribing including reduced polypharmacy, use of more appropriate medicines formulation and more appropriate choice of medicine. When ‘harder’ outcome measures have been included, such as hospitalizations or mortality in elderly patients, available evidence indicates that whilst interventions could improve knowledge and adherence they did not reduce mortality or hospital admissions with one study showing an increase in hospital admissions. Robust health economic studies of medication reviews remain rare. However a review of cost-effectiveness analyses of medication reviews found no studies in which the cost of the intervention was greater than the benefit. The value of medication reviews is now generally accepted despite lack of robust research evidence consistently demonstrating cost or clinical effectiveness compared with traditional care. Medication reviews can be more effectively deployed in the future by targeting, multi-professional involvement and paying greater attention to medicines which could be safely stopped.

Blenkinsopp, Alison; Bond, Christine; Raynor, David K

2012-01-01

308

Medical malpractice  

PubMed Central

Objective To examine the causal effects of doctor-patient relations and the severity of a medical outcome on medical patient perceptions and malpractice intentions in the event of an adverse medical outcome. Design Randomized between-subjects experimental design. Patients were given scenarios depicting interactions between an obstetric patient and her physician throughout the patient's pregnancy, labor, and delivery. Participants One hundred twenty-eight postpartum obstetric patients were approached for participation, of whom 104 completed the study. Main outcome measures Patients' perceptions of physician competence and intentions to file a malpractice claim. Results Positive physician communication behaviors increased patients' perceptions of physician competence and decreased malpractice claim intentions toward both the physician and the hospital. A more severe outcome increased only patients' intentions to sue the hospital. Conclusion These results provide empiric evidence for a direct, causal effect of the doctor-patient relationship on medical patients' treatment perceptions and malpractice claim intentions in the event of an adverse medical outcome.

Moore, Philip J; Adler, Nancy E; Robertson, Patricia A

2000-01-01

309

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

310

Injection and Extraction Systems and Beam Tuning Procedures of Coupled Cyclotrons.  

National Technical Information Service (NTIS)

The following description of injection and ejection systems, and the recommendations given for the tuning of coupled cyclotrons have a limited scope. Each cyclotron facility has its own peculiarities the energy range, the maximum intensity, the various ty...

R. Beck, B. Bru, M. Duval, J. Ferme, C. Ricaud

1986-01-01

311

The beam dynamics study for the CYCIAE-100 cyclotron  

NASA Astrophysics Data System (ADS)

A new RIB project, Beijing Radioactive Ion-beam Facility (BRIF), has been started at CIAE since 2004. For this project, a 100 MeV high intensity compact cyclotron, CYCIAE-100, is selected as the driving accelerator for radioactive ion beam production. The cyclotron will provide the proton beam of 75-100 MeV with an intensity of 200-500 ?A. The features of the cyclotron have already been described in several papers published elsewhere. In this paper the beam dynamics study is reviewed systematically. The basic parameters and numerical calculations results on the static orbit and accelerated orbit are given. The space charge effects, including the mutual interaction of neighboring multiple bunches in the radial direction, are studied with OPAL-CYCL code, and the current limit determined by space charge effects for this machine is predicted by fully 3D simulation.

Zhang, Tianjue; Yao, Hongjuan; Yang, Jianjun; Zhong, Junqing; An, Shizhong

2012-06-01

312

Cyclotron resonances in a non-neutral multispecies ion plasma  

NASA Astrophysics Data System (ADS)

Shifts of the cyclotron mode frequencies, away from the single particle limit, are observed to be proportional to the measured E × B rotation frequency in a non-neutral ion plasma. These cylindrical ion plasmas consist of 24Mg+, 25Mg+, and 26Mg+ with H3O+, and O2+ impurities. Laser cooling of the 24Mg+ majority species enables temperature control over the range 10-5 < T < 10-2 eV, as well as determination of cyclotron mode frequencies from launched wave absorption. At moderately low temperatures, the m? = 1 and m? = 2 cyclotron frequency shifts are well described by cold fluid theory for an equilibrium square profile. However, for T < 10-3 eV, centrifugal mass separation can shift the mode frequency back towards the single particle limit.

Affolter, M.; Anderegg, F.; Driscoll, C. F.; Dubin, D. H. E.

2013-03-01

313

Nonlinear plasma-wave interactions during ion cyclotron wave heating  

NASA Astrophysics Data System (ADS)

Ion cyclotron resonant frequency (ICRF) heating has been proved to be an efficient method to heat ions in fusion devices. For present and future ICRF heating experiments, the input power is usually over mega-watt. As a result of such high input power, nonlinear wave-particle interaction may play a very important role in the process of ion heating. To fully account for the plasma-wave interaction physics, computer simulations are performed using the PIC code implemented in VORPAL framework (C. Nieter and J. R.Cary, J. Comp. Phys. 196, 448 (2004)). It is found that near the lower hybrid resonance(LHR), the parametric decay into an ion wave and a quasi-mode could be triggered as the incident wave frequency is larger than twice the ion cyclotron frequency. Ions are thus heated near the LHR. In addition, ion heating at half-harmonic cyclotron frequencies is also observed, and the heating mechanism is discussed.

Xiang, Nong; Cary, John R.; Gan, C. Y.

2011-11-01

314

Cyclotron-resonance maser in a magnetic mirror.  

PubMed

A cyclotron-resonance maser (CRM) experiment is performed in a high-gradient magnetic field using a low-energy electron beam ( approximately 10 keV/1 A). The magnetic field exceeds 1.63 T, which corresponds to a 45-GHz cyclotron frequency. The CRM radiation output is observed in much lower frequencies, between 6.6 and 20 GHz only. This discrepancy is explained by the finite penetration depth of the electrons into the growing magnetic field, as in a magnetic mirror. The electrons emit radiation at the local cyclotron frequency in their reflection point from that magnetic mirror; hence, the radiation frequency depends mostly on the initial electron energy. A conceptual reflex gyrotron scheme is proposed in this paper, as a CRM analogue for the known reflex klystron. PMID:11970042

Caspi, R; Jerby, E

1999-08-01

315

Spectra and Neutron Dosimetry Inside a PET Cyclotron Vault Room  

SciTech Connect

The neutron field around a PET cyclotron was investigated during 18F radioisotope production with an 18 MeV proton beam. Pairs of thermoluminescent dosemeters, TLD600 and TLD700, were used as thermal neutron detector inside a Bonner Spheres Spectrometer to measure the neutron spectra at three different positions inside the cyclotron's vault room. Neutron spectra were also determined by Monte Carlo calculations. The hardest spectrum was observed in front of cyclotron target and the softest was noticed at the antipode of target. Neutron doses derived from the measured spectra vary between 11 and 377 mSv/{mu}A-h of proton integrated current, Doses were also measured with a single-moderator remmeter, with an active thermal neutron detector, whose response in affected by the radiation field in the vault room.

Vega-Carrillo, Hector Rene [Unidades Academicas: Estudios Nucleares e Ing. Electrica. Universidad Autonoma de Zacatecas, A.P. 336, 98000 Zacatecas, Zac. Mexico (Mexico); Mendez, Roberto [Universidad Europea Miguel de Cervantes, Valladolid (Spain); Iniguez, Maria Pilar [Facultad de Ciencias de la Universidad de Valladolid, Valladolid (Spain); Marti-Climent, Joseph; Penuelas, Ivan [Servicio de Medicina Nuclear, Clinica Universitaria de la Universidad de Navarra (Spain); Barquero, Raquel [Hospital Universitario Rio Hortega, Valladolid (Spain)

2006-09-08

316

Cassini observations of ion cyclotron waves and ions anisotropy  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

317

Zero-frequency cyclotron wave on an intense relativistic-electron beam  

Microsoft Academic Search

The zero-frequency cyclotron wave is studied on an unneutralized, magnetized relativistic-electron beam. This stationary mode occurs where the Doppler-shifted beam-cyclotron dispersion branch crosses the wavenumber axis. In this experiment zero-frequency-cyclotron waves have been generated by the injection of foil (and foilless) diode beams into a drift tube. A linear-cyclotron wave-dispersion theory is presented, which includes the radial electron-energy variation gamma(r)

T. P. Starke; H. V. Wong; W. W. Rienstra; B. N. Moore; Edward Cornet; H. A. Davis

1983-01-01

318

Fluid equations in the presence of electron cyclotron current drive  

SciTech Connect

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

Jenkins, Thomas G.; Kruger, Scott E. [Tech-X Corporation, 5621 Arapahoe Avenue, Boulder, Colorado 80303 (United States)

2012-12-15

319

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

320

Electron cyclotron emission diagnostics on the large helical device  

NASA Astrophysics Data System (ADS)

The electron cyclotron emission (ECE) diagnostic system is installed on the large helical device (LHD). The system includes the following instruments: a heterodyne radiometer, a Michelson spectrometer, and a grating polychromator. A 63.5 mm corrugated waveguide system is fully utilized. Large collection optics and notch filters at the frequency of the LHD electron cyclotron heating (ECH) were developed for this system. In addition to these filters, the rectangular waveguide notch filters, the ECE measurement with the radiometer has been successfully performed during the ECH.

Nagayama, Y.; Kawahata, K.; England, A.; Ito, Y.; Bretz, N.; McCarthy, M.; Taylor, G.; Doane, J.; Ikezi, H.; Edlington, T.; Tomas, J.

1999-01-01

321

Improved tuning and matching of ion cyclotron systems  

SciTech Connect

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

Swain, D.W.; Goulding, R.H.; Baity, F.W.; Hoffman, D.J. [Oak Ridge National Lab., TN (United States); Pinsker, R.I.; deGrassie, J.S.; Petty, C.C. [General Atomics, San Diego, CA (United States)

1996-09-01

322

Analysis of gamma-ray burst spectra with cyclotron lines  

NASA Technical Reports Server (NTRS)

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

Kargatis, Vincent; Liang, Edison P.

1992-01-01

323

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

324

Phase-sensitive cyclotron frequency measurements at ultralow energies.  

PubMed

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

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

2011-09-30

325

Hybrid simulation of ion cyclotron resonance in the solar wind: Evolution of velocity distribution functions  

Microsoft Academic Search

Resonant interaction between ions (oxygen ions O+5 and protons) and ion cyclotron waves is investigated using a one dimensional hybrid code. Ion cyclotron waves are self-consistently generated by an ion cyclotron anisotropy instability. We focus on the detailed acceleration process of ions. The energization of oxygen ions due to waves is found to have two stages. During the first stage,

Xing Li; Shadia R. Habbal

2005-01-01

326

Cyclotron emission from accretion plasma columns in magnetic cataclysmic variable stars  

Microsoft Academic Search

Pure cyclotron spectra of polars produced during their low accretion states are deduced. We used the working hypothesis that the cyclotron emission is produced by electrons spiraling down the dipole magnetic field lines and forming an accretion plasma column on top of the magnetic pole of a white dwarf. The velocity distribution function of electrons emitting cyclotron radiation is assumed

B. Kalomeni; E. R. Pekünlü; K. Yakut

2005-01-01

327

Laboratory and cyclotron requirements for PET research  

SciTech Connect

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

Schlyer, D.J.

1993-06-01

328

Medical Scientists  

MedlinePLUS

... little supervision, forming their own hypotheses and developing experiments, accordingly. They often lead teams of technicians, and ... prospective medical scientists the opportunity to develop their experiments and, sometimes, to supervise undergraduates. Ph.D. programs ...

329

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

330

Medication Treatment  

MedlinePLUS

... behavior, such as to reduce self-injury or aggression. Once a symptom is no longer a problem, ... of repetitive behaviors; decrease anxiety, irritability, tantrums, and aggressive behavior; and improve eye contact. Tricyclics These medications ...

331

Beyond the Medical Record  

PubMed Central

Background Studies before and since the 1999 Institute of Medicine report have noted the limitations of using medical record reporting for reliably quantifying and understanding medical error. Quantitative macro analyses of large datasets should be supplemented by small-scale qualitative studies to provide insight into micro-level daily events in clinical and hospital practice that contribute to errors and adverse events and how they are reported. Design The study design involved semistructured face-to-face interviews with residents about the medical errors in which they recently had been involved and included questions regarding how those errors were acknowledged. Objective This paper reports the ways in which medical error is or is not reported and residents' responses to a perceived medical error. Participants Twenty-six residents were randomly sampled from a total population of 85 residents working in a 600-bed teaching hospital. Measurements Outcome measures were based on analysis of cases residents described. Using Ethnograph and traditional methods of content analysis, cases were categorized as Documented, Discussed, and Uncertain. Results Of 73 cases, 30 (41.1%) were formally acknowledged and Documented in the medical record; 24 (32.9%) were addressed through Discussions but not documented; 19 cases (26%) cases were classified as Uncertain. Twelve cases involved medication errors, which were acknowledged in different categories. Conclusions The supervisory discussion, the informal discussion, and near-miss contain important information for improving clinical care. Our study also shows the need to improve residents' education to prepare them to recognize and address medical errors.

Rosenthal, Marilynn M; Cornett, Patricia L; Sutcliffe, Kathleen M; Lewton, Elizabeth

2005-01-01

332

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

333

Frequency shifts and modulation effects due to solenoidal magnetic field inhomogeneities in ion cyclotron mass spectrometry  

NASA Astrophysics Data System (ADS)

Solenoidal (i.e. axially symmetric) magnetic field inhomogeneities, which in addition have symmetry under the operation z --> -z are the most important to Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometry since they introduce frequency shifts at first-order in perturbation theory. Frequency shifts for all three fundamental modes are derived for the leading second-order and fourth-order solenoidal inhomogeneities without any restrictions on the initial conditions. The analytical frequency shifts agree very well with frequency shifts obtained from numerical trajectory calculations using the exact classical equations of motion. The effect of the inhomogeneity on the ion trajectory is solved analytically. For a strong magnetic bottle field, the cyclotron motion is frequency modulated at twice the z-oscillation frequency resulting in sidebands. However, the amplitude of these sidebands is negligibly small for typical inhomogeneity strengths. The effect of a magnetized ICR trap on the homogeneity of the magnetic field is studied by analytical methods. We find that the leading magnetic bottle field decreases as d-3, where d is the cylindrical ion trap diameter.

Mitchell, Dale W.; Rockwood, Alan L.; Smith, Richard D.

1995-02-01

334

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

335

Medication Math  

NSDL National Science Digital Library

Medication calculation needs to be completed accurately for proper patient treatment. In this section you will need to review and improve your medication math. Understanding math: Math and Culture Refresher: Take the amount of fluid in the bottle and times that by the dose ordered. Then divide this number by the amount of drug in the bottle. This will give you the volume of the drug that you need to administer. Diagram of formulas Math Formulas Math ...

Joey

2008-10-16

336

Radioisotope-production facility at JAEA-TIARA used for medical and plant physiological research  

Microsoft Academic Search

A radioisotope-production facility at the Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) of the Japan Atomic Energy Agency (JAEA) allows us to produce radioisotopes using accelerated beam from an AVF cyclotron. The facility has been constructed for research and development of potentially useful radioisotopes in medical research and physiological studies of plants. Experiments in these fields require a variety

N. S. Ishioka; S. Watanabe; H. Matsuoka; S. Matsuhashi

2005-01-01

337

Dynamic effects on cyclotron scattering in pulsar accretion columns  

NASA Technical Reports Server (NTRS)

A resonant scattering model for photon reprocessing in a pulsar accretion column is presented. The accretion column is optically thin to Thomson scattering and optically thick to resonant scattering at the cyclotron frequency. Radiation from the neutron star surface propagates freely through the column until the photon energy equals the local cyclotron frequency, at which point the radiation is scattered, much of it back toward the star. The radiation pressure in this regime is insufficient to stop the infall. Some of the scattered radiation heats the stellar surface around the base of the column, which adds a softer component to the spectrum. The partial blocking by the accretion column of X-rays from the surface produces a fan beam emission pattern. X-rays above the surface cyclotron frequency freely escape and are characterized by a pencil beam. Gravitational light bending produces a pencil beam pattern of column-scattered radiation in the antipodal direction, resulting in a strongly angle-dependent cyclotron feature.

Brainerd, J. J.; Meszaros, P.

1991-01-01

338

An intense alpha ion source for INRS cyclotron  

SciTech Connect

An intense PIG alpha source for INRS has been developed with low arc power and low gas flow. Generally, the alpha yield of the new source is twice as much as the old one. The structure and character of the source and its experimental results both on the bench and cyclotron are described in this paper.

Chen Ling,-xing; Chen Mao-bei

1985-10-01

339

Cyclotron maser emission of auroral Z mode radiation  

NASA Technical Reports Server (NTRS)

Results are presented suggesting that loss cone driven cyclotron maser emission by upgoing electrons, closely analogous to auroral kilometric radiation (AKR), may be the mechanism behind the observed Z mode radiation. With this hypothesis, the lack of a strong correlation between the Z mode radiation and AKR is not surprising; the ray paths for the X mode and the Z mode are markedly different, with the former directed upward and the latter downward. In addition, it is expected that the generation of the Z mode will be favored only in regions where the ratio of the plasma frequency to the electron cyclotron frequency is greater than or approximately equal to 0.3, that is, where the X mode radiation is suppressed. If the fraction of the radiation generated that crosses the cyclotron layer is large, then the argument in favor of the loss cone driven cyclotron maser as the source of the observed Z mode radiation is a strong one. The spatial growth rates are fairly large in comparison with those for the X mode, and there seems to be little doubt that Z mode radiation should be generated under conditions that differ only slightly from those for the generation of X mode radiation in AKR.

Melrose, D. B.; Hewitt, R. G.; Dulk, G. A.

1983-01-01

340

Electron-cyclotron-heating experiments in tokamaks and stellarators  

SciTech Connect

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

England, A.C.

1983-01-01

341

Recent results on ion cyclotron and combined heating of TEXTOR  

Microsoft Academic Search

The recent experimental activity in the field of auxiliary heating and related topics on TEXTOR is reviewed. TEXTOR is equipped with up to 4 MW of ion cyclotron heating power and 3.4 MW of neutral beam injection. The combination of the radiating boundary concept with high auxiliary power has extended the improved confinement domain to the large density regime and

R. Koch; A. M. Messiaen; J. Ongena; R. Van Nieuwenhove; G. Van Oost; G. Van Wassenhove; P. Dumortier; F. Durodie; P. E. Vandenplas; D. Van Esteer; M. Vervier; R. R. Weynants; K. H. Finken; H. Euringer; V. Philipps; U. Samm; B. Unterberg; J. Winter; G. Bertschinger; H. G. Esser; G. Fuchs; B. Giesen; E. Hintz; F. Hoenen; P. Hütteman; L. Könen; M. Korten; H. R. Koslowski; A. Krämer-Flecken; M. Lochter; G. Mank; A. Pospieszczyk; B. Schweer; H. Soltwisch; G. Telesca; R. Uhlemann; G. Waidmann; G. H. Wolf; J. Boedo; D. Gray; D. L. Hillis; T. Oyevaar; H. F. Tammen; T. Tanabe; Y. Ueda

1995-01-01

342

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

343

Parameters of the eigenellipsoid for separated sector cyclotrons.  

National Technical Information Service (NTIS)

The analytical expressions of the elements of the beam matrix corresponding to the eigenellipsoid for a beam injected on an equilibrium orbit of a cyclotron are presented. The four dimensional phase space of the horizontal plane is only considered. Some r...

J. Ferme

1989-01-01

344

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

345

Acceleration of dust grains by means of electromagnetic cyclotron waves  

Microsoft Academic Search

It is shown that charged dust grains can be accelerated by the nonuniform space charge electric fields that are created by the ponderomotive force of circularly polarized electromagnetic cyclotron waves. The relevance of our investigation to dust energization in the Earth's mesospheric plasma is stressed.

P. K. Shukla; L. Stenflo; A. A. Mamun; D. P. Resendes; G. Sorasio

2002-01-01

346

Tests of the ITER Prototype Ion Cyclotron Antenna  

Microsoft Academic Search

A prototype antenna for the ITER ion cyclotron system, based on a resonant double loop antenna design from the 1998 Engineering Design Activity, has been built and tested. Electrical properties of the antenna were measured and were in agreement with theoretical calculations. Results of high-power experiments in vacuum showed that the antenna could operate at voltages in excess of 60

David W. Swain; Richard H. Goulding; Philip M. Ryan

2002-01-01

347

Design options for an ITER ion cyclotron system.  

National Technical Information Service (NTIS)

Recent changes have occurred in the design requirements for the ITER ion cyclotron system, requiring in-port launchers in four main horizontal ports to deliver 50 MW of power to the plasma. The design is complicated by the comparatively large antenna-sepa...

D. W. Swain F. W. Baity T. S. Bigelow P. M. Ryan R. H. Goulding

1995-01-01

348

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

349

Cyclotron Resonance of Electrons Trapped in a Microwave Cavity  

ERIC Educational Resources Information Center

Describes an experiment in which the free-electron cyclotron resonance of electrons trapped in a microwave cavity by a Penning trap is observed. The experiment constitutes an attractive alternative to one of the Gardner-Purcell variety. (Author/GS)

Elmore, W. C.

1975-01-01

350

High frequency acceleration system of the DC-280 cyclotron  

NASA Astrophysics Data System (ADS)

The radio-frequency (RF) accelerating system designed at the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research (FLNR JINR), for the DC-280 cyclotron is described. The cyclotron is intended to increase the capabilities and efficiency of experiments on the synthesis of superheavy elements and investigate their nuclear-physical and chemical properties. The DC-280 isochronous heavyion cyclotron will produce an accelerated beam of ions in the range from neon to uranium. The results of the preliminary and 3D numerical calculations of the main cavity of this system are reported. The preliminary calculations by the Coaxresonator software have allowed the geometry of the main cavity to be chosen. 3D numerical simulation has completely confirmed the correctness of the preliminary calculations. For example, the difference in frequency between the preliminary and 3D numerical calculations is no larger than 1%. The electric-field component maps obtained from the simulations are used to calculate the beam dynamics in the cyclotron.

Gulbekyan, G. G.; Zarubin, V. B.; Karamysheva, G. A.; Karamyshev, O. V.; Franko, J.

2012-12-01

351

Electron cyclotron current drive experiments on DIII-D.  

National Technical Information Service (NTIS)

Electron Cyclotron Current Drive (ECCD) experiments on the DIII-D tokamak have been performed using 60 GHz waves launched from the high field side of the torus. Preliminary analysis indicates rf driven currents between 50 and 100 kA in discharges with tot...

R. A. James G. Giruzzi B. Gentile L. Rodriguez A. Fyaretdinov

1990-01-01

352

A Search for Cyclotron Resonance Features with INTEGRAL  

NASA Astrophysics Data System (ADS)

We present an INTEGRAL observation of the Cen- Crux region in order to search the electron cyclotron resonance scattering features from the X-ray binary pulsars. During the AO1 200 ks observation, we clearly detected 4 bright X-ray binaries, 1 Seyfert Galaxy, and 4 new sources in the field of view. Es- pecially from GX301-2, the cyclotron resonance fea- ture is detected at about ˜ 37 keV, and width of 3 4 keV. In addition, the depth of the resonance fea- ture strongly depends on the X-ray luminosity. This is the first detection of luminosity dependence of the resonance depth. The well-known twin pulsars are spatially separated by JEM-X and IBIS/ISGRI, and pulse periods are measured individually; 296.90 sec for 1E1145-6141 and 292.5 sec for 4U1145-619. The cyclotron resonance feature is marginally detected from 1E1145.1-6141. Cen X-3 was very dim during the observation and poor statistics disable us to de- tect the resonance features. Key words: X-rays; High mass X-ray binary pulsar; cyclotron resonance feature.

Okada, Y.; Niko, H.; Kokubun, M.; Makishima, K.; Nakajima, M.; Mihara, T.; Terada, Y.; Nagase, F.; Tanaka, Y.

2004-10-01

353

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

354

Measurements of Optically Thin Electron Cyclotron Emission from Relativistic Electrons.  

National Technical Information Service (NTIS)

Electron cyclotron emission (ECE) from hot, relativistic electrons has been measured simulataneously at several optically thin frequencies (f/f/sub ce/ = 4.6, 7.0, and 9.6) on the Tandem Mirror Experiment-Upgrade. A method to determine the temporal evolut...

R. A. James E. Silver D. Boyd R. F. Ellis S. Jantz

1987-01-01

355

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

356

Wave propagation across ion cyclotron resonance harmonic layers  

Microsoft Academic Search

Wave propagation across ion cyclotron resonance layers is investigated by use of a boundary layer analysis for a perpendicularly stratified, weakly inhomogeneous plasma. Corresponding to the situation in many plasmas of interest, it is assumed that the wave frequency is much less than the ion plasma frequency, but that the ratio of ion plasma frequency to wave frequency times the

K. Imre; H. Weitzner

1987-01-01

357

The Demineralized Water System for the NRL Cyclotron.  

National Technical Information Service (NTIS)

Since it is necessary to remove up to 4 MW of heat from various magnets, power supplies, and other heat-generating units of the NRL Cyclotron, an air-handling system was considered impractical to handle this heat load. Therefore, the demineralized water s...

R. O. Bondelid

1968-01-01

358

Electron cyclotron heating and current drive in toroidal geometry  

SciTech Connect

The Principal Investigator has continued to work on problems associated both with the deposition and with the emission of electron cyclotron power in toroidal plasmas. We have investigated the use of electron cyclotron resonance heating for bringing compact tokamaks (BPX) to ignition-like parameters. This requires that we continue to refine the modeling capability of the TORCH code linked with the BALDUR 1 {1/2} D transport code. Using this computational tool, we have examined the dependence of ignition on heating and transport employing both theoretical (multi-mode) and empirically based transport models. The work on current drive focused on the suppression of tearing modes near the q = 2 surface and sawteeth near the q = 1 surface. Electron cyclotron current drive in CIT near the q =2 surface was evaluated for a launch scenario where electron cyclotron power was launched near the equatorial plane. The work on suppression of sawteeth has been oriented toward understanding the suppression that has been observed in a number of tokamaks, in particular, in the WT-3 tokamak in Kyoto. To evaluate the changes in current profile (shear) near the q =1 surface, simulations have been carried out using the linked BALDUR-TORCH code. We consider effects on shear resulting both from wave-induced current as well as from changes in conductivity associated with changes in local temperature. Abstracts and a paper relating to this work is included in Appendix A.

Kritz, A.H.

1991-11-01

359

Heavy cyclotron mass in ferromagnetic substance UGe2  

Microsoft Academic Search

We have measured transverse magnetoresistance and the de Haas-van Alphen effect in an anisotropic ferromagnetic substance UGe2. Fermi surfaces consist of multiple-connected large cylindrical sheets and ellipsoidal closed ones. Carriers possess large cyclotron effective masses, ranging from 2 to 2m0.

K. Satoh; S. W. Yun; I. Ukon; I. Umehara; H. Aoki; S. Uji; T. Shimizu; I. Sakamoto; M. Hunt; P. Meeson; P.-A. Probst; M. Springford

1992-01-01

360

Electron cyclotron thruster new modeling results preparation for initial experiments  

NASA Technical Reports Server (NTRS)

The following topics are discussed: a whistler-based electron cyclotron resonance heating (ECRH) thruster; cross-field coupling in the helicon approximation; wave propagation; wave structure; plasma density; wave absorption; the electron distribution function; isothermal and adiabatic plasma flow; ECRH thruster modeling; a PIC code model; electron temperature; electron energy; and initial experimental tests. The discussion is presented in vugraph form.

Hooper, E. Bickford

1993-01-01

361

Shielding for the variable energy cyclotron at Calcutta  

Microsoft Academic Search

Shielding calculations are done for the AVF Cyclotron under construction at Calcutta. Concrete shields are designed to reduce the fast neutron flux to less than the maximum permissible levels outside the shields. Earth shields are designed to reduce the fast neutron flux outside the building to less than the maximum permissible levels for public exposure. Experimentally measured values of half-value

G. Muthukrishnan; H. Singh; R. Mukherjee

1977-01-01

362

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

SciTech Connect

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

Li, H.

1993-01-01

363

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

364

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

365

Medical Biofilms  

PubMed Central

For more than two decades, Biotechnology and Bioengineering has documented research focused on natural and engineered microbial biofilms within aquatic and subterranean ecosystems, wastewater and waste-gas treatment systems, marine vessels and structures, and industrial bioprocesses. Compared to suspended culture systems, intentionally engineered biofilms are heterogeneous reaction systems that can increase reactor productivity, system stability, and provide inherent cell: product separation. Unwanted biofilms can create enormous increases in fluid frictional resistances, unacceptable reductions in heat transfer efficiency, product contamination, enhanced material deterioration, and accelerated corrosion. Missing from B&B has been an equivalent research dialogue regarding the basic molecular microbiology, immunology, and biotechnological aspects of medical biofilms. Presented here are the current problems related to medical biofilms; current concepts of biofilm formation, persistence, and interactions with the host immune system; and emerging technologies for controlling medical biofilms.

2009-01-01

366

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

367

Medical marijuana.  

PubMed

The Florida Supreme Court heard oral arguments in April regarding a glaucoma patient's request for a medical exception to the State prohibition on use of marijuana. [Name removed] was convicted on possession and cultivation charges, and a trial judge refused to allow a medical necessity defense. A State appeals court subsequently overturned [name removed]'s conviction. The case focuses on whether the legislature intended to prohibit such a defense when it declared in 1993 that the substance had no medicinal benefits. PMID:11366533

1999-04-30

368

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

369

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

370

Phosphorus Doping Using Electron Cyclotron Resonance Plasma for Large-Area Polycrystalline Silicon Thin Film Transistors  

NASA Astrophysics Data System (ADS)

We have investigated phosphorus doping using an electron cyclotron resonance (ECR) plasma, for application to the poly-Si driving circuits of liquid crystal displays or image sensors. The PH3/He was ionized and accelerated to poly-Si and c-Si substrates with a self bias of -220 V. The P concentration, as detected by secondary ion mass spectroscopy (SIMS), is ˜5×1021 cm-3 at the surface, which decayed to ˜1017 cm-3 within 50 100 nm depth. The surface is found to be etched during doping. The etching is restored by adding a small amount of SiH4 and the sheet resistance R s decreases. The optimized as-irradiated R s is ˜ 1× 105 ?/\\Box and 1.7× 102 ?/\\Box for poly-Si and (110) c-Si, respectively. The dependence of R s on the substrates and the anomalous diffusion constants derived from SIMS are also discussed.

Kakinuma, Hiroaki; Mohri, Mikio; Tsuruoka, Taiji

1994-01-01

371

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

372

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

373

Particle and fluid simulations of resistive current-driven electrostatic ion cyclotron waves  

NASA Technical Reports Server (NTRS)

The results from 1-D numerical simulations of electrostatic ion cyclotron waves (EIC) are presented for a model in which the electrons are a resistive (collisional) fluid. Simulations of both the kinetic and fluid descriptions are performed and compared in order to assess the fundamental limitations of fluid theory for EIC waves. The effect of ion-neutral collisions is also included using a simple Monte Carlo technique. It is found that a small ion-neutral collision frequency destroys the frequency harmonic coupling of kinetic EIC waves and tends to validate the fluid description. The saturation amplitude of the current-driven EIC instability is in agreement with recent laboratory experiments. The coherent nature (extremely narrow spectral width) and phase velocity agree with ground based (coherent backscatter radars) and in situ observations of current-driven EIC waves in the high latitude ionosphere.

Seyler, Charles E.; Providakes, Jason

1987-01-01

374

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

375

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

376

High Power Cyclotrons for Accelerator Driven System (ADS)  

NASA Astrophysics Data System (ADS)

We present an accelerator module based on a injector cyclotron and a Superconducting Ring Cyclotron (SRC) able to accelerate H2+ molecules. H2+ molecules are extracted from the SRC stripping the binding electron by a thin carbon foil. The SRC will be able to deliver proton beam with maximum energy of 800 MeV and a maximum power of 8 MW. This module is forecasted for the DAEdALUS (Decay At rest Experiment for ?cp At Laboratory for Underground Science) experiment, which is a neutrino experiment proposed by groups of MIT and Columbia University. Extensive beam dynamics studies have been carrying out in the last two years and proved the feasibility of the design. The use of H2+ molecules beam has three main advantages: 1) it reduces the space charge effects, 2) because of stripping extraction, it simplifies the extraction process w.r.t. single turn extraction and 3) we can extract more than one beam out of one SRC. A suitable upgraded version of the cyclotron module able to deliver up to 10MW beam is proposed to drive ADS. The accelerator system which is presented, consists of having three accelerators modules. Each SRC is equipped with two extraction systems delivering two beams each one with a power up to 5 MW. Each accelerator module, feeds both the two reactors at the same time. The three accelerators modules assure to maintain continuity in functioning of the two reactors. In normal operation, all the three accelerators module will deliver 6.6 MW each one, just in case one of the three accelerator module will be off, due to a fault or maintenance, the other two modules are pushed at maximum power of 10 MW. The superconducting magnetic sector of the SRC, as well as the normal conducting sector of the injector cyclotron, is calculated with the TOSCA module of OPERA3D. Here the main features of the injector cyclotron, of the SRC and the beam dynamic along the cyclotrons are presented.

Calabretta, Luciano

2012-03-01

377

Medical marijuana.  

PubMed Central

Although many clinical studies suggest the medical utility of marijuana for some conditions, the scientific evidence is weak. Many patients in California are self-medicating with marijuana, and physicians need data to assess the risks and benefits. The only reasonable solution to this problem is to encourage research on the medical effects of marijuana. The current regulatory system should be modified to remove barriers to clinical research with marijuana. The NIH panel has identified several conditions for which there may be therapeutic benefit from marijuana use and that merit further research. Marijuana should be held to the same evaluation standards of safety and efficacy as other drugs (a major flaw in Proposition 215) but should not have to be proved better than current medications for its use to be adopted. The therapeutic window for marijuana and THC between desired effect and unpleasant side effects is narrow and is a major reason for discontinuing use. Although the inhaled route of administration has the benefit of allowing patients to self-titrate the dose, the smoking of crude plant material is problematic. The NIH panel recommended that a high priority be given to the development of a controlled inhaled form of THC. The presence of a naturally occurring cannabinoid-receptor system in the brain suggests that research on selective analogues of THC may be useful to enhance its therapeutic effects and minimize adverse effects.

Marmor, J B

1998-01-01

378

Medical exceptionalism.  

PubMed

How should we assess the historical development of health care? Many historians are deeply reluctant to endorse ideas involving progress in human affairs, including the evolution of modern medicine. We tend to think either that our present situation is little better than in the past, or that most kinds of value judgments about history are subjective and inappropriate. A laudatory approach to medical history commonly adopted by "amateur" medical historians in the tradition of Sir William Osler has often been eschewed by "professionals" as faulty, feel-good history. But Osler was right in his belief that, on balance, the progress of medicine has been spectacular, that modern health care offers one of the finest examples of the possibility of "man's redemption of man." Written objectively, medical history is about progress and achievement, and can properly seen as inspiring. If we mordantly or relativistically dismiss the unprecedentedly high quality of modern health care, we lose the ability to understand why citizens value it so highly, and this distorts our understanding of current issues. We also lose our sense of the wonders of human and medical achievement. PMID:23179032

Bliss, Michael

2012-01-01

379

Medical tourism.  

PubMed

Medical tourism is becoming popular as an alternative to the high cost of health care in the United States and as an inexpensive resource for cosmetic surgery. The occupational health nurse is an excellent resource to assist in the pre-decision due diligence and post-decision travel health counseling. PMID:20102121

Tompkins, Olga S

2010-01-01

380

Medical marijuana.  

PubMed

Although many clinical studies suggest the medical utility of marijuana for some conditions, the scientific evidence is weak. Many patients in California are self-medicating with marijuana, and physicians need data to assess the risks and benefits. The only reasonable solution to this problem is to encourage research on the medical effects of marijuana. The current regulatory system should be modified to remove barriers to clinical research with marijuana. The NIH panel has identified several conditions for which there may be therapeutic benefit from marijuana use and that merit further research. Marijuana should be held to the same evaluation standards of safety and efficacy as other drugs (a major flaw in Proposition 215) but should not have to be proved better than current medications for its use to be adopted. The therapeutic window for marijuana and THC between desired effect and unpleasant side effects is narrow and is a major reason for discontinuing use. Although the inhaled route of administration has the benefit of allowing patients to self-titrate the dose, the smoking of crude plant material is problematic. The NIH panel recommended that a high priority be given to the development of a controlled inhaled form of THC. The presence of a naturally occurring cannabinoid-receptor system in the brain suggests that research on selective analogues of THC may be useful to enhance its therapeutic effects and minimize adverse effects. PMID:9656007

Marmor, J B

1998-06-01

381

Improving cancer treatment with cyclotron produced radionuclides  

SciTech Connect

This new DOE proposal appropriately builds on past developments. The development and application of radionuclides for diagnosis, treatment and research has been a continuing concern for more than the past three decades. A brief description of this development and previous achievements was considered important in order to provide a frame of reference for the evolving program here. Earlier, the use of certain radionuclides, radon progeny and I-131 in particular, and also x-rays, had been developed by the work of such pioneers as Failla, Quimby and Marinelli. In 1952, at the instigation of Dr. C.P. Rhoads, Director of both Memorial Hospital and Sloan-Kettering Institute, the restoration of the Department of Physics and Biophysics was undertaken in response to a perceived need to promote the utilization of radionuclides and of high energy radiations for therapeutic, diagnostic and research purposes. This resulted in several research and developmental projects with close clinical collaboration in areas of radiation treatment; medical studies with radionuclides and labeled compounds; the diagnostic uses of x-rays; and some projects in surgery and other clinical areas. Aspects of some of these projects that have had some relevance for the evolving AEC-DOE projects are outlined briefly. 34 refs.

Laughlin, J.S.; Larson, S.M.

1988-01-01

382

Remote target removal for the Oak Ridge 86-inch Cyclotron  

SciTech Connect

A remotely operated target remover has been plaed in operation at the 86-Inch Cyclotron located in Oak Ridge. The system provides for the remote removal of a target from inside the cyclotron, loading it into a cask, and the removal of the cask from the 1.5 m (5-ft) shielding walls. The remote system consists of multiple electrical and pneumatically operated equipment which is designed for controlled step-by-step operation, operated with an electrical control panel, and monitored by a television system. The target remover has reduced the radiation exposures to operating personnel at the facility and has increased the effective operating time. The system is fast, requires a minimum of skill to operate, and has demonstrated both reliability and durability.

Walls, A.A.

1982-01-01

383

LH wave absorption by mode conversion near ion cyclotron harmonics  

SciTech Connect

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

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

1981-02-01

384

Transparency of magnetized plasma at the cyclotron frequency.  

PubMed

Electromagnetic radiation is strongly absorbed by a magnetized plasma if the radiation frequency equals the cyclotron frequency of plasma electrons. It is demonstrated that absorption can be completely canceled in the presence of a magnetostatic field of an undulator, or a second radiation beam, resulting in plasma transparency at the cyclotron frequency. This effect is reminiscent of the electromagnetically induced transparency (EIT) of three-level atomic systems, except that it occurs in a completely classical plasma. Unlike the atomic systems, where all the excited levels required for EIT exist in each atom, this classical EIT requires the excitation of nonlocal plasma oscillation. A Lagrangian description was used to elucidate the physics of the plasma transparency and control of group and phase velocity. This control leads to applications for electromagnetic pulse compression and electron/ion acceleration. PMID:12225144

Shvets, G; Wurtele, J S

2002-09-01

385

Sawtooth control in ITER using ion cyclotron resonance heating  

SciTech Connect

Numerical modeling of the effects of ion cyclotron resonance heating (ICRH) on the stability of the internal kink mode suggests that ICRH should be considered as an essential sawtooth control tool in ITER. Sawtooth control using ICRH is achieved by directly affecting the energy of the internal kink mode rather than through modification of the magnetic shear by driving localized currents. Consequently, ICRH can be seen as complementary to the planned electron cyclotron current drive actuator, and indeed will improve the efficacy of current drive schemes. Simulations of the ICRH distribution using independent RF codes give confidence in numerical predictions that the stabilizing influence of the fusion-born alphas can be negated by appropriately tailored minority (3)He ICRH heating in ITER. Finally, the effectiveness of all sawtooth actuators is shown to increase as the q = 1 surface moves towards the manetic axis, whilst the passive stabilization arising from the alpha and NBI particles decreases.

Chapman, I. T. [EURATOM CCFE Fus Assoc, Culham Sci Ctr, Abingdon, Oxon, England; Graves, J P [Ecole Polytechnique Federale de Lausanne, Switzerland; Johnson, T. [KTH, EES, EURATOM VR Assoc., Stockholm, Sweden; Asunta, O. [Aalto University, Finland; Bonoli, P. [Massachusetts Institute of Technology (MIT); Choi, M. [General Atomics; Jaeger, E. F. [Oak Ridge National Laboratory (ORNL); Jucker, M. [Ecole Polytechnique Federale de Lausanne, Switzerland; Sauter, O. [Ecole Polytechnique Federale de Lausanne, Switzerland

2011-01-01

386

Test-particle drifts in traveling waves with cyclotron frequencies  

NASA Astrophysics Data System (ADS)

When a test particle moves in the field of a traveling wave with the cyclotron frequency, a particle-acceleration difference is found to appear between the first half-cycle of the Larmor motion, during which the particle has a velocity component in the direction of the wave propagation, and the second half-cycle, during which it has a velocity component in the opposite direction. This asymmetric acceleration modifies the cyclotron-resonance trajectory, yielding the physical origin of the particle drift perpendicular both to the wave propagation and background magnetic-field lines. A perturbation method in the orbit theory sucessfully gives analytic expressions for and numerical calculations demonstrate the drift generation. The result is applicable to particle-flux control of magnetized plasmas. (c) 1995 The American Physical Society

Hatakeyama, Rikizo; Sato, Naoyuki; Sato, Noriyoshi

1995-12-01

387

Ion Behavior in an Electrically Compensated Ion Cyclotron Resonance Trap  

PubMed Central

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

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

2010-01-01

388

Status report on the JAERI AVF cyclotron system  

NASA Astrophysics Data System (ADS)

The AVF cyclotron system at JAERI Takasaki has been smoothly operated without serious troubles since the first beam extraction of 50 MeV 4He2+ in March 1991. A yearly operation time is about 3200 hours on an average for past several years. In the last three years, we performed some improvements and developments as follows: stabilization of the cyclotron beam, renewal of computers and basic programs for the control system, installation of a new ECR ion source and reconstruction of the rotary shutter. Furthermore, two series of M/Q=4 and M/Q=2 cocktail beams have been developed continuously. Now we are modifying the RF cavities for the flat-top acceleration by superimposing the fifth-harmonic frequency on the fundamental one. .

Nakamura, Y.; Nara, T.; Agematsu, T.; Ishibori, I.; Tamura, H.; Kurashima, S.; Yokota, W.; Okumura, S.; Fukuda, M.; Arakawa, K.

2001-12-01

389

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

390

Production of nitrogen-13-labeled ammonia by using 11MeV medical cyclotron: our experience.  

PubMed

A method has been developed for the production of (13)N-labeled ammonia in usable quantities with negligible contamination. A system was developed and a process for the production of nitrogen-13 ammonium ions from a target material in the form of a dilute solution of ethanol in natural water, i.e. the bombardment of oxygen-16 with protons within the target material. The system includes a device for producing a proton beam which travels along a pre selected path and strikes the target material in a target chamber. This target chamber is positioned in the path of the proton beam such that subjection of the target material to the beam produces nitrogen-13 atoms and alpha particles. These nitrogen-13 atoms are converted in the aqueous solution to ammonium ions and oxides and are conducted from the target holder to a purification cartridge for collecting a purified product containing the ammonium ions. PMID:19936337

Kumar, Rajeev; Singh, Harkirat; Jacob, Mattakaottu; Anand, Surendra Pal; Bandopadhyaya, Guru Pad

2009-01-01

391

Optimisation of the Radiation Shielding of Medical Cyclotrons using a Genetic Algorithm  

Microsoft Academic Search

medicine include 201Tl (T1\\/2 = 73.06 h) and 67 Ga (T1\\/2 = 78.26 h). These radioisotopes are generated by bombarding the thick copper substrates electroplated with enriched parent target materials with 30 MeV protons at ~ 400 µA beam current. The target bombardments result in the production of intense fields of high-energy neutrons and gamma rays. Therefore, in order to

Bhaskar Mukherjee

392

Cyclotron resonance maser experiment in a nondispersive waveguide  

Microsoft Academic Search

A cyclotron-resonance maser (CRM) oscillator experiment in which a spiraling electron beam interacts with a transverse electromagnetic wave in a nondispersive waveguide is presented. The experiment employs a low-energy (<5 keV) low-current (<1 A) electron beam in a two-wire (Lecher type) waveguide. The microwave output frequency is tuned in this experiment by the axial magnetic field in the range 3.5-6.0

E. Jerby; A. Shahadi; R. Drori; M. Korol; M. Einat; M. Sheinin; V. Dikhtiar; V. Grinberg; M. Bensal; T. Harhel; Y. Baron; A. Fruchtman; V. L. Granatstein; G. Bekefi

1996-01-01

393

Cyclotron autoresonance maser (CARM) amplifiers for RF accelerator drivers  

Microsoft Academic Search

Cyclotron autoresonance maser (CARM) amplifiers are under investigation as a possible source of high-power (>100 MW), high-frequency (>10 GHz) microwaves for powering the next generation of linear colliders. The authors have completed the design study for a high-power, short pulse, 17.136 GHz CARM amplifier, utilizing a 500 kV linear induction accelerator. A three period bifilar helical wiggler with a wiggle

W. L. Menninger; B. G. Danly; C. Chen; K. D. Pendergast; R. J. Temkin; D. L. Goodman; D. L. Birx

1991-01-01

394

Design options for an ITER ion cyclotron system  

SciTech Connect

Recent changes have occurred in the design requirements for the ITER ion cyclotron system, requiring in-port launchers in four main horizontal ports to deliver 50 MW of power to the plasma. The design is complicated by the comparatively large antenna-separatrix distance of 10--20 cm. Designs of a conventional strap launcher and a folded waveguide launcher than can meet the new requirements are presented.

Swain, D.W.; Baity, F.W.; Bigelow, T.S.; Ryan, P.M.; Goulding, R.H.; Carter, M.D.; Stallings, D.C.; Batchelor, D.B.; Hoffman, D.J.

1995-09-01

395

Cyclotron Resonance in Graphene at Ultrahigh Magnetic Fields  

Microsoft Academic Search

To investigate the effects of intentional and unintentional doping on the conduction properties of CVD-grown large-area graphene, we have performed high-field cyclotron resonance (CR) measurements on graphene. We accessed ultrahigh magnetic fields using the Single-Turn Coil System at NHMFL-Los Alamos, which can produce peak fields over 300 T in ˜2.5 mus pulses. We investigated magneto-infrared transmission at 10.6 mum in

L. G. Booshehri; C. H. Mielke; S. A. Crooker; L. Ren; E. H. Haroz; Z. Jin; Z. Sun; Z. Yan; J. M. Tour; J. Kono

2011-01-01

396

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

397

A cyclotron microbeam and its application to biomedical samples  

Microsoft Academic Search

The experimental setup to produce a cyclotron microbeam of 27 MeV alpha particles and 25 MeV protons is described. Using an ordinary doublet of quadrupole magnets with an aperture diameter of 2.5 in. as a focussing lens, a beam line with demagnification factors DCD = -3.3 and DDC = -16 was constructed. A beam spot with a diameter of less

Hiroko Koyama-Ito; Eiko Wada; Akira Ito

1987-01-01

398

A VE-RFQ-injector for a cyclotron  

Microsoft Academic Search

Based on the development of the variable energy 4-rod-RFQ, a new injector for the ISL heavy ion cyclotron at the HMI Berlin (the former VICKSI machine) is under construction. The ECR source together with two VE-RFQs will replace the 8UD-Tandem injector to meet the demands of solid state physics users. The design of the new RFQ injector and the status

A. Schempp; O. Engels; F. Marhauser; H. Homeyer; W. Pelzer

1995-01-01

399

Electromagnetic ion\\/ion cyclotron instability - Theory and simulations  

Microsoft Academic Search

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

D. Winske; N. Omidi

1992-01-01

400

Satellite ionosonde records: resonances below the cyclotron frequency.  

PubMed

Resonant responses observed by the topside ionosonde in the Canadian satellite Alouette II are examined. In addition to the well-known plasma resonances, several subsidiary resonances are identified below the electron cyclotron frequency. Their patterns of occurrence are not consistent with a suggested explanation of induced magnetic dipole radiation; rather they appear to result from harmonic stimulation of the plasma resonances and beat-frequency generation. PMID:17740425

Barrington, R E; Hartz, T R

1968-04-12

401

Second harmonic electron cyclotron current drive experiments on T-10  

Microsoft Academic Search

Results of the electron cyclotron current drive experiment at the second harmonic resonance on the T-10 tokamak are presented. High frequency (HF) power up to 1.2 MW was launched from the low field side. A maximum driven current of 35 kA and current drive efficiency etaCD = 0.05 A\\/W at an electron temperature Tc(O) = 4 keV and a density

V. V. Alikaev; A. A. Bagdasarov; A. A. Borshegovskij; V. V. Chistyakov; M. M. Dremin; Yu. A. Gorelov; A. V. Gorshkov; Yu. V. Esipchuk; D. B. Evdokimov; A. Ya. Kislov; D. A. Kislov; V. A. Krupin; L. K. Kuznetsova; S. E. Lysenko; G. E. Notkin; Yu. D. Pavlov; V. I. Poznyak; K. A. Razumova; I. N. Roj; P. V. Savrukhin; V. V. Sannikov; A. V. Sushkov; V. M. Trukhin; N. L. Vasin; V. A. Vershkov; G. G. Denisov; V. I. Belousov; V. A. Flyagin; C. B. Forest; J. M. Lohr; T. C. Luce; R. W. Harvey; B. Grek

1995-01-01

402

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

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

403

Small bowel lymphoma  

Microsoft Academic Search

Opinion statement  Treatment of small bowel lymphoma requires the expertise of medical and surgical subspecialists. The two most important factors\\u000a that determine the optimal treatment are histology and staging of small bowel lymphoma. Other factors that may affect treatment\\u000a include age, multiple areas of involvement, tumor size, and perforation. At present, the best treatment for gastrointestinal\\u000a lymphoma (stage IE disease) is

Renard A. Rawls; Kenneth J. Vega; Bruce W. Trotman

2003-01-01

404

Cryogenic system upgrade for the National Superconducting Cyclotron Laboratory  

SciTech Connect

The National Superconducting Cyclotron Laboratory (NSCL) is a National Science Foundation supported facility, with additional support from Michigan State University (MSU). The facility consists of two superconducting cyclotrons and over fifty individual cryostats, each containing several superconducting magnets that are used in the beam transport system. The facility also has a superconducting ion source and a large superconducting spectrograph. To support this facility we operated two helium refrigerators producing approximate 900W at 4.5K. In July of 1999, construction of a new beam analysis system, the A1900, was started. The laboratory was reconfigured to couple the two cyclotrons in series to enable the facility to produce higher intensity radioactive beams than previously possible in the stand-alone mode. In addition, the helium distribution system was upgraded with new transfer lines and a new distribution box. The new requirements increased the refrigeration load to more than 1 KW at 4.5K. To support this increased cryogenic load, the existing two helium cryogenic plants, were at best, marginal in capacity. This would have required both plants to run at full capacity, maximum efficiency and availability. To achieve higher reliability, availability, and process transient capacity for magnet cool down and filling, a decision was made to obtain a larger cryogenic plant to support the new system. The following paper describes the important aspects and capabilities of the new cryogenic system to accomplish this goal.

A. McCartney; V. Ganni; H. Laumer; D. Arenius; J. Creel; W. Chronis; K. Davidson

2002-05-10

405

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

406

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

407

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

408

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

409

[Methadone: Medical treatment or dealing?].  

PubMed

A woman with schizophrenia in methadone treatment was admitted for treatment of psychotic symptoms and cocaine addiction. Her prescribed medication was a 400 mg daily dose of methadone. It became evident during her hospitalisation that she was only taking a small part of the medication herself and she sold the rest of the methadone to finance her addiction of cocaine. To address this kind of misuse of prescribed medication, this paper examines the importance of following guidelines put forward by the NBH (National Board of Health). PMID:19091198

Nielsen, Mette Odegaard; Hetmar, Ole

2008-12-01

410

Medical Telemetry  

NASA Technical Reports Server (NTRS)

Telemetry is the process whereby physiological or other data is acquired by instruments, translated into radio signals and j sent to a receiving station where the signals are decoded and recorded. Extensively used in I space operations, it is finding new Earth applications, among them transmission of medical data between emergency vehicles and hospitals. For example, transmission of an electrocardiogram from an ambulance to a hospital enables a physician to read the telemetered EKG and advise ambulance attendants on emergency procedures. Central Medical Emergency Dispatch (CMED) operates as a regional emergency medical communications center for Cleveland, Ohio and Cuyahoga County. The CMED system includes radio and telephone communications from hospital-to-hospital and from ambulance-to-hospital, but for improved emergency life support CMED sought to add a county-wide telemetry capability. The problem was that there were only eight radio frequencies available for telemetry and there were more than 30 potential users in Cleveland alone. NASA's Lewis Research Center volunteered its expert assistance. The Center's engineers studied the systems of other telemetry using cities, surveyed area hospitals to assure compatibility of telemetry equipment, and advised what types of equipment would be needed in emergency vehicles and at the various hospitals. The Lewis plan suggested that CMED be designated the central coordinating agency for the Cuyahoga County system, monitoring all telemetry frequencies and, when requested, assigning one not in use or one to be used at a sufficient distance that it would create no interference problem.

1978-01-01

411

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

412

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

413

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

414

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

SciTech Connect

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. [Department of Radiology, University of Iowa, Iowa City IA 52242 (United States); Department of Physics, University of Iowa, Iowa City IA 52242 (United States); Department of Radiology, University of Iowa, Iowa City IA 52242 (United States)

2012-12-19

415

The efficient production of high specific activity copper-64 using a biomedial cyclotron  

SciTech Connect

We have developed a method for the efficient and cost-effective production of high specific activity Cu-64, via the Ni-64(p,n)Cu-64 reaction, using a small biomedical cyclotron. Nickel-64 (95% enriched) has been successfully electroplated on gold disks at thicknesses of {approximately}20-300 {mu}ms and bombarded with protons at beam currents up to {approximately}45 microamps. An automated target has been designed to facilitate the irradiations on a biomedical cyclotron. Techniques have been developed for the rapid and efficient separation of Cu-64 from Ni-64 and other reaction byproducts using ion exchange chromatography. An initial production run using 55 mg of 95% enriched Ni-64 yielded 20 GBq of Cu-64 with specific activity of 4.5 GBq/{mu}g (determined by serial dilution titrations with TETA). In a series of experiments, bombardment of 18.7-23.7 mg of 85% enriched Ni-64 has produced 8.9-18.5 GBq of Cu-64 with specific activity of 4.5 GBq/{mu}g (determined by serial dilution titrations with TETA). In a series of experiments, bombardment of 18.7-23.7 mg of 85% enriched Ni-64 has produced 8.9-18.5 GBq of Cu-64 (133 {plus_minus} 10 MBq/{mu}Ahr) with specific activity of 3.5 GBq-11.5 GBq/{mu}g. The amount and specific activity of the Cu-64 produced is more than adequate for both PET and therapy experiments. The Cu-64 produced in more than adequate for both PET and therapy experiments. The Cu-64 had been used to radiolabel PTSM (pyruvaldehyde bis (N4-methylthiosemicarbazone)-used to quantify blood flow), a monoclonal antibody (1A3) and octreotide. An efficient technique for recycling the costly enriched nickel-64 target material has been developed. Nickel eluted off the separation column is collected, boiled to dryness and redissolved in the electroplating bath. Using this method, 94.2 {plus_minus} 3.2% of the Ni-64 has been recovered. The technique described provides a simple, cost-effective method for the cyclotron production of Cu-64.

McCarthy, D.W.; Shefer, R.E.; Klinkowstein, R.E.; Bass, L.A. [Newton Scientific Inc., Winchester, MA (United States)] [and others

1996-05-01

416

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

417

Ray trajectories near the electron cyclotron resonance surface in an axisymmetric magnetic trap  

SciTech Connect

Characteristic features of the propagation of electromagnetic electron cyclotron waves in the vicinity of the electron cyclotron resonance surface are investigated both analytically and numerically with allowance for variation in the magnetic field strength and a corresponding variation in the magnetic field direction. It is demonstrated that variation in the magnetic field direction can qualitatively change the wave propagation pattern and can markedly affect the efficiency of electron cyclotron resonance plasma heating in an axisymmetric magnetic trap.

Gospodchikov, E. D.; Smolyakova, O. B. [Russian Academy of Sciences, Institute of Applied Physics (Russian Federation)

2011-09-15

418

Observation of a high-confinement regime in a tokamak plasma with ion cyclotron resonance heating  

Microsoft Academic Search

The H mode in ion cyclotron-resonance-heated plasmas has been investigated with and without additional neutral beam injection. Ion cyclotron-resonance heating can cause the transition into a high-confinement regime (H mode) in combination with beam heating. The H mode, however, has also been realized-for the first time-with ion cyclotron-resonance heating alone in the D (H)-hydrogen minority scheme at an absorbed rf

K. Steinmetz; J.-M. Noterdaeme; F. Wagner; F. Wesner; J. Baeumler; G. Becker; H. S. Bosch; M. Brambilla; F. Braun; H. Brocken; A. Eberhagen; R. Fritsch; G. Fussmann; O. Gehre; J. Gernhardt; G. v. Gierke; E. Glock; O. Gruber; G. Haas; J. Hofmann; F. Hofmeister; A. Izvozchikov; G. Janeschitz; F. Karger; M. Keilhacker; O. Klüber; M. Kornherr; K. Lackner; G. Lisitano; E. van Mark; F. Mast; H. M. Mayer; K. McCormick; D. Meisel; V. Mertens; E. R. Müller; H. Murmann; H. Niedermeyer; W. Poschenrieder; S. Puri; H. Rapp; H. Röhr; F. Ryter; K.-H. Schmitter; F. Schneider; C. Setzensack; G. Siller; P. Smeulders; F. Söldner; E. Speth; K.-H. Steuer; O. Vollmer; H. Wedler; D. Zasche

1987-01-01

419

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

NASA Astrophysics Data System (ADS)

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.; Dendy, R. O.; Chapman, S. C.; Cook, J. W. S.

2014-01-01

420

Recent Developments in Simulations of an Inverse Cyclotron for Intense Muon Beams  

NASA Astrophysics Data System (ADS)

A number of recent developments have led to simulations of an inverse cyclotron for cooling intense muon beams for neutrino factories and muon colliders. Such a device could potentially act as a novel beam cooling mechanism for muons, and it would be significantly smaller and cheaper than other cooling channel designs. Realistic designs are still being explored, but the first simulations of particle tracking in the inverse cyclotron, with accumulation in the cyclotron core, have been done with electrostatic simulations in the particle-in-cell code VORPAL. We present an overview of the muon inverse cyclotron concept and recent simulation results.

Paul, Kevin; Cormier-Michel, Estelle; Hart, Terrence; Summers, Donald

2010-11-01

421

Recent Developments in Simulations of an Inverse Cyclotron for Intense Muon Beams  

SciTech Connect

A number of recent developments have led to simulations of an inverse cyclotron for cooling intense muon beams for neutrino factories and muon colliders. Such a device could potentially act as a novel beam cooling mechanism for muons, and it would be significantly smaller and cheaper than other cooling channel designs. Realistic designs are still being explored, but the first simulations of particle tracking in the inverse cyclotron, with accumulation in the cyclotron core, have been done with electrostatic simulations in the particle-in-cell code VORPAL. We present an overview of the muon inverse cyclotron concept and recent simulation results.

Paul, Kevin; Cormier-Michel, Estelle [Tech-X Corporation, Boulder, CO 80303 (United States); Hart, Terrence; Summers, Donald [University of Mississippi-Oxford, University, MS 38677 (United States)

2010-11-04

422

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

423

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

424

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.

425

Microwave-Excited Microplasma Thrusters Using Surface Wave and Electron Cyclotron Resonance Discharges  

NASA Astrophysics Data System (ADS)

Downsizing spacecrafts has recently been focused on to decrease mission costs and to increase launch rates, and missions with small satellites would bring a great advantage of reducing their risks. Such a concept supports a new approach to developing precise, reliable, and low-cost micropropulsion systems. We have studied two types of microwave-excited microplasma thrusters, using surface wave-excited and electron cyclotron resonance-excited discharges. Microwaves of S-band (4 GHz) and X-band (11 GHz) were employed to excite the plasma in these experiments, with the feed or propellant gases of Ar and He. A microplasma thruster of electrothermal type consisted of a surface wave-excited microplasma source, and a converging-diverging micronozzle to obtain the thrust. For 11-GHz microwaves at a power of 6 W, a thrust of 1.1 mN and a specific impulse of 90 s were obtained at an Ar gas flow rate of 40 sccm, where the plasma electron density was 1.2x10^20 m-3, and the gas temperature was 1.5x10^3 K; under the same conditions for 4-GHz microwaves, the thrust, specific impulse, electron density, and gas temperature were 0.93 mN, 80 s, 7.0x10^19 m-3, and 8.0x10^2 K, respectively. A microplasma thruster of electromagnetic type had a microplasma source excited by electron cyclotron resonance with external magnetic fields, to obtain the thrust through accelerating ions by ambipolar electric fields. Optical emission spectrum was dominated by Ar^+ ion lines in the microplasma thruster of electromagnetic type, owing to higher electron temperatures at lower feed-gas pressures.

Mori, Daisuke; Kawanabe, Tetsuo; Takao, Yoshinori; Eriguchi, Koji; Ono, Kouichi

2012-10-01

426

Thermoluminescence in medical dosimetry.  

PubMed

Thermoluminescence dosimetry (TLD) is applied worldwide for personal and medical dosimetry. TLD method has resulted in many interesting findings in medicine as TL dosimeters have many relevant advantages such as high sensitivity, small physical size, tissue equivalence, etc. The main characteristics of various TL materials used in radiation measurements and their practical consequences are overviewed: well defined TL glow curve, batch homogeneity, signal stability after irradiation, precision and accuracy, response with dose, and influence of energy. In this paper a brief summary of the advances in the application of thermally stimulated luminescence (TSL) to dosimetry in radiation therapy application is presented. PMID:22633888

Rivera, T

2012-12-01

427

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

428

First commissioning results with the Grenoble test electron cyclotron resonance ion source at iThemba LABS.  

PubMed

iThemba Laboratory for Accelerator Based Science (iThemba LABS) is a multi-disciplinary accelerator facility. One of its main activities is the operation of a separated-sector cyclotron with a K-value of 200, which provides beams of various ion species. These beams are used for fundamental nuclear physics research in the intermediate energy region, radioisotope production, and medical physics applications. Due to the requirements of nuclear physics for new ion species and higher energies, the decision was made to install a copy of the so-called Grenoble test source (GTS) at iThemba LABS. In this paper, we will report on the experimental setup and the first results obtained with the GTS2 at iThemba LABS. PMID:22380170

Thomae, R; Conradie, J; Delsink, H; Du Plessis, H; Fourie, D; Hitz, D; Klopp, M; Kohler, I; Kuechler, D; Lussi, C; McAlister, R; Ntshangase, S; Sakildien, M

2012-02-01

429

First commissioning results with the Grenoble test electron cyclotron resonance ion source at iThemba LABS  

SciTech Connect

iThemba Laboratory for Accelerator Based Science (iThemba LABS) is a multi-disciplinary accelerator facility. One of its main activities is the operation of a separated-sector cyclotron with a K-value of 200, which provides beams of various ion species. These beams are used for fundamental nuclear physics research in the intermediate energy region, radioisotope production, and medical physics applications. Due to the requirements of nuclear physics for new ion species and higher energies, the decision was made to install a copy of the so-called Grenoble test source (GTS) at iThemba LABS. In this paper, we will report on the experimental setup and the first results obtained with the GTS2 at iThemba LABS.

Thomae, R.; Conradie, J.; Delsink, H.; Du Plessis, H.; Fourie, D.; Klopp, M.; Kohler, I.; Lussi, C.; McAlister, R.; Ntshangase, S.; Sakildien, M. [iThemba LABS, P.O Box 722, Somerset West 7130 (South Africa); Hitz, D. [CEA/DRFMC, 17 Av. Des Martyrs, 38054, Grenoble Cedex 9 (France); Kuechler, D. [CERN, BE/ABP/HSL, 1211 Geneva 23 (Switzerland)

2012-02-15

430

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

431

Electromagnetic Waves near the Proton Cyclotron Frequency: STEREO Observations  

NASA Astrophysics Data System (ADS)

Transverse, near-circularly polarized, parallel-propagating electromagnetic waves around the proton cyclotron frequency were found sporadically in the solar wind throughout the inner heliosphere. They could play an important role in heating and accelerating the solar wind. These low-frequency waves (LFWs) are intermittent but often occur in prolonged bursts lasting over 10 minutes, named "LFW storms." Through a comprehensive survey of them from Solar Terrestrial Relations Observatory A using dynamic spectral wave analysis, we have identified 241 LFW storms in 2008, present 0.9% of the time. They are left-hand (LH) or right-hand (RH) polarized in the spacecraft frame with similar characteristics, probably due to Doppler shift of the same type of waves or waves of intrinsically different polarities. In rare cases, the opposite polarities are observed closely in time or even simultaneously. Having ruled out interplanetary coronal mass ejections, shocks, energetic particles, comets, planets, and interstellar ions as LFW sources, we discuss the remaining generation scenarios: LH ion cyclotron instability driven by greater perpendicular temperature than parallel temperature or by ring-beam distribution, and RH ion fire hose instability driven by inverse temperature anisotropy or by cool ion beams. The investigation of solar wind conditions is compromised by the bias of the one-dimensional Maxwellian fit used for plasma data calibration. However, the LFW storms are preferentially detected in rarefaction regions following fast winds and when the magnetic field is radial. This preference may be related to the ion cyclotron anisotropy instability in fast wind and the minimum in damping along the radial field.

Jian, L. K.; Wei, H. Y.; Russell, C. T.; Luhmann, J. G.; Klecker, B.; Omidi, N.; Isenberg, P. A.; Goldstein, M. L.; Figueroa-Viñas, A.; Blanco-Cano, X.

2014-05-01

432

Glow plasma trigger for electron cyclotron resonance ion sources  

NASA Astrophysics Data System (ADS)

Electron cyclotron resonance ion sources (ECRISs) are particularly useful for nuclear, atomic, and high energy physics, as unique high current generators of multicharged ion beams. Plasmas of gas discharges in an open magnetic trap heated by pulsed (100 ?s and longer) high power (100 kW and higher) high-frequency (greater than 37.5 GHz) microwaves of gyrotrons is promising in the field of research in the development of electron cyclotron resonance sources for high charge state ion beams. Reaching high ion charge states requires a decrease in gas pressure in the magnetic trap, but this method leads to increases in time, in which the microwave discharge develops. The gas breakdown and microwave discharge duration becomes greater than or equal to the microwave pulse duration when the pressure is decreased. This makes reaching the critical plasma density initiate an electron cyclotron resonance (ECR) discharge during pulse of microwave gyrotron radiation with gas pressure lower than a certain threshold. In order to reduce losses of microwave power, it is necessary to shorten the time of development of the ECR discharge. For fast triggering of ECR discharge under low pressure in an ECRIS, we initially propose to fill the magnetic trap with the plasmas of auxiliary pulsed discharges in crossed ExB fields. The glow plasma trigger of ECR based on a Penning or magnetron discharge has made it possible not only to fill the trap with plasma with density of 1012 cm-3, required for a rapid increase in plasma density and finally for ECR discharge ignition, but also to initially heat the plasma electrons to Te~20 eV.

Vodopianov, A. V.; Golubev, S. V.; Izotov, I. V.; Nikolaev, A. G.; Oks, E. M.; Savkin, K. P.; Yushkov, G. Yu.

2010-02-01

433

Medical marijuana.  

PubMed

Grassroots AIDS activist groups denounce the Clinton Administration's stance on banning medicinal use of marijuana due to the lack of clinical evidence supporting its benefits. The 1997 meeting of the San Francisco Medical Society and the New England Journal of Medicine both agreed, following a review of 75 scientific studies of the medicinal benefits of marijuana, that the benefits of smoked marijuana include relief from pain and the reduction of nausea caused by anti-cancer drugs. The Federal government is attempting to punish physicians for prescribing marijuana to their patients, a situation being opposed by the Bay Area Physicians for Human Rights who have initiated a suit against the government. A hearing to stop this prosecution was scheduled for March 21. PMID:11364533

Baker, R; Bowers, M

1997-03-01

434

Tests of the ITER Prototype Ion Cyclotron Antenna  

SciTech Connect

A prototype antenna for the ITER ion cyclotron system, based on a resonant double loop antenna design from the 1998 Engineering Design Activity, has been built and tested. Electrical properties of the antenna were measured and were in agreement with theoretical calculations. Results of high-power experiments in vacuum showed that the antenna could operate at voltages in excess of 60 kV for multisecond pulses. The stub tuning arrangement proposed for use on ITER was demonstrated to work. These results validate the original design concept of the ITER antenna.

Swain, David W.; Goulding, Richard H.; Ryan, Philip M. [Oak Ridge National Laboratory (United States)

2002-03-15

435

Electron cyclotron current drive experiments on T-10  

NASA Astrophysics Data System (ADS)

The results of electron current drive experiments on the T-10 tokamak are presented. The total RF power was up to 2.5 MW, the electron temperature was up to 7 keV and the maximum driven current was 110 kA. The current drive efficiency ?CD was approximately 0.1 A/W. The value of ?CD and its dependence on the plasma parameters agree satisfactorily with the linear theory, corrected for the finite confinement time of resonant electrons. In discharges with large beta poloidal, ?p approx 3, complete replacement of the inductive current by noninductive electron cyclotron current drive and bootstrap current was obtained

Alikaev, V. V.; Bagdasarov, A. A.; Borshegovskij, A. A.; Dremin, M. M.; Gorelov, A. Yu.; Esipchuk, V. Yu.; Kislov, A. Ya.; Kislov, D. A.; Lysenko, S. E.; Notkin, G. E.; Parail, V. V.; Razumova, K. A.; Roj, I. N.; Trukhin, V. M.; Vasin, N. L.; Denisov, G. G.; Petelin, M. I.; Flyagin, V. A.; Lohr, J. M.; Harvey, R. W.; James, R. A.

1992-10-01

436

Deposition of diamondlike films by electron cyclotron resonance microwave plasmas  

NASA Technical Reports Server (NTRS)

Hard a-C:H films have been deposited through electron cyclotron resonance (ECR) microwave plasma decomposition of CH4 diluted with H2 gas. It has been found that hard diamondlike films could only be produced under a RF-induced negative self-bias of the substrate stage. Raman spectra indicate the deposition of two distinct film types: one film type exhibiting well-defined bands at 1360 and 1580/cm and another displaying a broad Raman peak centered at approximately 1500/cm. Variation of the mirror magnetic-field profile of the ECR system was examined, demonstrating the manipulation of film morphology through the extraction of different ion energies.

Pool, F. S.; Shing, Y. H.

1990-01-01

437

Potential applications of an electron cyclotron resonance multicusp plasma source  

SciTech Connect

An electron cyclotron resonance (ECR) multicusp plasmatron has been developed by feeding a multicusp bucket arc chamber with a compact ECR plasma source. This novel source produces large (about 25 cm diam), uniform (to within {plus minus}10%), dense ({gt}10{sup 11} cm{sup {minus}3}) plasmas of argon, helium, hydrogen, and oxygen. It has been operated to produce an oxygen plasma for etching 12.7 cm (5 in.) positive photoresist-coated silicon wafers with uniformity within {plus minus}8%. Results and potential applications of this new ECR plasma source for plasma processing of thin films are discussed.

Tsai, C.C.; Berry, L.A.; Gorbatkin, S.M.; Haselton, H.H.; Roberto, J.B.; Stirling, W.L. (Oak Ridge National Laboratory, Oak Ridge, TN (USA))

1990-05-01

438

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

439

Beam injection improvement for electron cyclotron resonance charge breeders  

NASA Astrophysics Data System (ADS)

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.; Galatà, A.

2012-02-01

440

Plasma heating near ion cyclotron resonance harmonic layer  

NASA Astrophysics Data System (ADS)

A survey of results is presented for plasma heating and wave propagations for incident waves with frequencies matching ion cyclotron resonance harmonics. It is assumed that outside the resonance layer geometrical optics is applicable, and the plasma is stratified perpendicularly to the equilibrium magnetic field. A boundary layer expansion is used near the resonance layer. Numerical results for the case of pure third and fundamental resonances are given. Ion-ion hybrid resonance case with the minority species at fundamental resonance is also presented.

Imre, Kaya; Weitzner, Harold

1987-09-01

441

Cyclotron line resonant transfer through neutron star atmospheres  

NASA Technical Reports Server (NTRS)

Monte Carlo methods are used to study in detail the resonant radiative transfer of cyclotron line photons with recoil through a purely scattering neutron star atmosphere for both the polarized and unpolarized cases. For each case, the number of scatters, the path length traveled, the escape frequency shift, the escape direction cosine, the emergent frequency spectra, and the angular distribution of escaping photons are investigated. In the polarized case, transfer is calculated using both the cold plasma e- and o-modes and the magnetic vacuum perpendicular and parallel modes.

Wang, John C. L.; Wasserman, Ira M.; Salpeter, Edwin E.

1988-01-01

442

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

443

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

444

Electron cyclotron resonance microwave ion sources for thin film processing  

SciTech Connect

Plasmas created by microwave absorption at the electron cyclotron resonance (ECR) are increasingly used for a variety of plasma processes, including both etching and deposition. ECR sources efficiently couple energy to electrons and use magnetic confinement to maximize the probability of an electron creating an ion or free radical in pressure regimes where the mean free path for ionization is comparable to the ECR source dimensions. The general operating principles of ECR sources are discussed with special emphasis on their use for thin film etching. Data on source performance during Cl base etching of Si using an ECR system are presented. 32 refs., 5 figs.

Berry, L.A.; Gorbatkin, S.M.

1990-01-01

445

Current drive with fast waves, electron cyclotron waves, and neutral injection in the D3-D tokamak  

NASA Astrophysics Data System (ADS)

Current drive experiments have been performed on the D3-D tokamak using fast waves, electron cyclotron waves, and neutral injection. Fast wave experiments were performed using a 4-strap antenna with 1 MW of power at 60 MHz. These experiments showed effective heating of electrons, with a global heating efficiency equivalent to that of neutral injection even when the single pass damping was calculated to be as small as 5 percent. The damping was probably due to the effect of multiple passes of the wave through the plasma. Fast wave current drive experiments were performed with a toroidally directional phasing of the antenna straps. Currents driven by fast wave current drive (FWCD) in the direction of the main plasma current of up to 100 kA were found, not including a calculated 40 kA of bootstrap current. Experiments with FWCD in the counter current direction showed little current drive. In both cases, changes in the sawtooth behavior and the internal inductance qualitatively support the measurement of FWCD. Experiments on electron cyclotron current drive have shown that 100 kA of current can be driven by 1 MW of power at 60 GHz. Calculations with a Fokker-Planck code show that electron cyclotron current drive (ECCD) can be well predicted when the effects of electron trapping and of the residual electric field are included. Experiments on driving current with neutral injection showed that effective current drive could be obtained and discharges with full current drive were demonstrated. Interestingly, all of these methods of current drive had about the same efficiency, 0.015(10)(exp 20) MA/MW/sq m.

Prater, R.; Petty, C. C.; Pinsker, R. I.; Chiu, S. C.; Degrassie, J. S.; Harvey, R. W.; Ikel, H.; Lin-Liu, Y. R.; Luce, T. C.; James, R. A.

1992-09-01

446

Current drive with fast waves, electron cyclotron waves, and neutral injection in the DIII-D tokamak  

SciTech Connect

Current drive experiments have been performed on the DIII-D tokamak using fast waves, electron cyclotron waves, and neutral injection. Fast wave experiments were performed using a 4-strap antenna with 1 MW of power at 60 MHz. These experiments showed effective heating of electrons, with a global heating efficiency equivalent to that of neutral injection even when the single pass damping was calculated to be as small as 5%. The damping was probably due to the effect of multiple passes of the wave through the plasma. Fast wave current drive experiments were performed with a toroidally directional phasing of the antenna straps. Currents driven by fast wave current drive (FWCD) in the direction of the main plasma current of up to 100 kA were found, not including a calculated 40 kA of bootstrap current. Experiments with FWCD in the counter current direction showed little current drive. In both cases, changes in the sawtooth behavior and the internal inductance qualitatively support the measurement of FWCD. Experiments on electron cyclotron current drive have shown that 100 kA of current can be driven by 1 MW of power at 60 GHz. Calculations with a Fokker-Planck code show that electron cyclotron current drive (ECCD) can be well predicted when the effects of electron trapping and of the residual electric field are included. Experiments on driving current with neutral injection showed that effective current drive could be obtained and discharges with full current drive were demonstrated. Interestingly, all of these methods of current drive had about the same efficiency, 0.015 {times} 10{sup 20} MA/MW/m{sup 2}.

Prater, R.; Petty, C.C.; Pinsker, R.I.; Chiu, S.C.; deGrassie, J.S.; Harvey, R.W.; Ikel, H.; Lin-Liu, Y.R.; Luce, T.C. (General Atomics, San Diego, CA (United States)); James, R.A. (Lawrence Livermore National Lab., CA (United States)); Porkolab, M. (Massachusetts Inst. of Tech., Cambridge, MA (United States)); Baity, F.W.; Goulding, R.H.; Hoffmann, D.J. (Oak Ridge National Lab., TN (United States)); Kawash

1992-09-01

447

Business ethics, medical ethics and economic medicalization  

Microsoft Academic Search

This paper explores the ethical implications of economic medicalization: where non-medical problems are transformed into medical problems in order to achieve the objective of shareholder wealth maximization. After considering differences between business ethics and medical ethics, economic medicalization arising from corporate marketing strategies is detailed. Both direct-to-consumer and more traditional physician centred marketing methods are considered. In addition, the economic

Geoffrey Poitras

2009-01-01

448

Ion cyclotron harmonics in auroral radar echoes: Real effect or analysis artifact?  

Microsoft Academic Search

Certain analyses of Canadian radar studies of auroral electrojet echoes have apparently shown spectra with multiple ion cyclotron harmonic peaks. On the basis of these, it has been argued that ion cyclotron effects must be important for all echo types seen by VHF radars, not just type 3. We reject this conclusion for two reasons: (1) at the altitude of

D. T. Farley; J. D. Sahr; J. F. Providakes

1991-01-01

449

Ion cyclotron harmonics in auroral radar echoes - Real effect or analysis artifact?  

Microsoft Academic Search

Certain analyses of Canadian radar studies of auroral electrojet echoes have apparently shown spectra with multiple ion cyclotron harmonic peaks. On the basis of these, it has been argued that ion cyclotron effects must be important for all echo types seen by VHF radars, not just type 3. This conclusion is rejected for two reasons: (1) at the altitude of

D. T. Farley; J. D. Sahr; J. F. Providakes

1991-01-01

450

Ion cyclotron harmonics in auroral radar echoes: Real effect or analysis artifact  

Microsoft Academic Search

Certain analyses of Canadian radar studies of auroral electrojet echoes have apparently shown spectra with multiple ion cyclotron harmonic peaks. On the basis of these, it has been argued that ion cyclotron effects must be important for all echo types seen by VHF radars, not just type 3. The authors reject this conclusion for two reasons: (1) at the altitude

D.T. Farley; J. D. Sahr; J. F. Providakes

1991-01-01