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  • 1
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A 2.45 GHz electron cyclotron resonance (ECR) ion source with a single mode resonator is being developed to produce high efficient single charged ion beams from exiguous gaseous elements. The source is intended to produce short and long half-life radioactive ion beams as well as stable ion beams for low and high energy experiments at ISAC [J. M. Poutissou, Proceedings of the ISAC Workshop (1994)]. It is obvious that for the radioactive ion beam production, the gas and ion transient time and the overall ionization efficiency are the most important parameters. The transient time is measured using ultrafast peizoelectric gas valve which could operate up to a frequency of 2 kHz. A unique feature of the source is that the plasma chamber is considerably smaller (∼170 times) than its resonance cavity in order to minimize the transient time. Quartz tubes with various diameters (5–20 mm) and 80 mm long are tested as the plasma chamber and the results are discussed. The effect of the transfer tube length, which links the target and the ion source on the transient time is also described. An axially symmetric five electrode extraction system containing three multiaperture electrodes was used to extract the beam. The source, including ECR coils and extraction system is placed in the middle of a 60 cm×60 cm×90 cm vacuum box to simulate the ISAC target module conditions. The preliminary results of the molecular and ion transient time studies, beam efficiency studies are also presented in this article. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A 2.45 GHz electron cyclotron resonance ion source has been designed and built to ionize radioactive atoms and produce single charged ion beams for the isotope separator and accelerator at TRIUMF. The source is characterized by its short axial length (8 cm) and the small pair of magnetic coils (diam=φ26 cm) placed adjacent to the source cavity. A small diameter quartz tube is inserted in the cavity to confine the plasma to a small volume and to shorten total ion transient time for the exotic gaseous elements with short and intermediate half life. The computer code POISSON is used to design the magnetic coils. A three-electrode extraction system simulated with the code IGUNE is used to study the beam extraction efficiency. In this article the design of the source, extraction system, and the preliminary results on beam emittance and energy spread are presented; the results on ion transient time, ionization efficiency, and beam extraction efficiency are presented in a separate article. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A 2.45 GHz ECR ion source for the ISAC on-line operation is being tested at the TRIUMF ion source test stand prior to its installation in the radioactive ion beam production target module. Steps were taken at the design stage to ensure short transient time and high ionization efficiency for single charged ions. Further considerations were given to radiation hardness, reliability, and remote handling capabilities. Transient time was measured using an ultrafast piezoelectric valve. Efficiencies were measured using calibrated gas leaks of stable and radioactive isotopes such as 127Xe. This article describes the overall characteristics of the source. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1435-1285
    Keywords: Key words Dobutamine stress echocardiography – contrast agent – endocardial detection – BY 963 ; Schlüsselwörter Dobutamin-¶Belastungsechokardiographie –¶Kontrastmittel –¶Endokarderkennung – BY 963
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Interpretation induzierter Wandbewegungsstörungen während der Dobutamin-Belastungsechokardiographie ist bei einem Teil der Patienten durch unzureichende Endokardabgrenzbarkeit beeinträchtigt. Bei 48 konsekutiven Patienten (mittleres Alter 62±9 Jahre, 32 Männer, 16 Frauen) mit vermuteter koronarer Herzkrankheit, bei denen die Indikation zur Koronarangiographie gestellt worden war, wurde untersucht ob die intravenöse Applikation des lungengängigen Echokontrastmittels BY 963 eine verbesserte Endokarderkennbarkeit im linken Ventrikel sowohl in Ruhe als auch unter Dobutaminbelastung (10 bis 40μg/kg/min + maximal 1mg Atropin) erlaubt. Für jedes der 16 linksventrikulären Segmente wurde die endokardiale Erkennbarkeit beurteilt. Durch Einsatz des Kontrastmittels BY 963 ließ sich die durchschnittliche Zahl nicht-auswertbarer Segmente um 58% von 5,2% auf 2,2% in Ruhe (p=0,008) und um 56% von 5,9% auf 2,6% unter maximaler Belastung (p=0,003) senken. Bei Patienten mit eingeschränkter Bildqualität (N=14), definiert als fehlende Beurteilbarkeit mindestens eines Wandsegmentes in Ruhe, konnte die durchschnittliche Zahl nicht-auswertbarer Segmente von 19,2% auf 8,2% (p=0,004) vor Belastung und von 19,2% auf 9,6% (p=0,006) unter maximaler Belastung gesenkt werden. Die größte Abnahme nicht-auswertbarer Segmente zeigte sich in den lateralen und anterioren Segmenten der apikalen Schnittebenen (maximal um 80%). Die verbesserte endokardiale Abgrenzbarkeit resultierte in einer größeren Übereinstimmung zwischen zwei Untersuchern in der Bewertung der Dobutamin-Belastungsechokardiogramme als normal oder pathologisch (Kappa=0,38 ohne Kontrast, Kappa=0,58 mit Kontrast). Die diagnostische Genauigkeit der Dobutamin-Belastungsechokardiographie in der Erfassung einer angiographisch signifikanten koronaren Herzkrankheit stieg geringfügig an. Schlußfolgerung: Bei Patienten mit eingeschränkter Endokarderkennbarkeit führt der Einsatz des Echokontrastmittels BY 963 zu einer verminderten Zahl nicht-auswertbarer Segmente, wobei die Verbesserung in den lateralen und anterioren Segmenten der apikalen Schnittebenen am ausgeprägtesten ist.
    Notes: Summary The interpretation of induced wall motion abnormalities during dobutamine stress echocardiography is affected in the case of impaired image quality. In 48 consecutive patients (mean age 62±9 years, 32 males, 16 females) with suspected coronary disease undergoing coronary angiography, the transpulmonary contrast agent BY 963 was given i.v. as bolus during dobutamine stress echocardiography (10–40μgkgmin, plus max. 1mg atropine) to analyze improvements in endocardial border delineation. For each of the 16 segments of the left ventricle, the endocardial border delineation was evaluated. Using BY 963 the average number of non-evaluable segments decreased by 58% from 5.2% to 2.2% at rest (p=0.008) and by 56% from 5.9% to 2.6% at maximal stress (p=0.003) as compared to the non-contrast study for all patients. In patients with impaired image quality, defined as at least 1 non-evaluable segment at rest without contrast enhancement (N=14), the number of non-evaluable segments decreased from 19.2% to 8.2% (p=0.004) at rest and from 19.2% to 9.6% (p=0.006) at maximal stress. The greatest decrease of non-evaluable segments was seen in the lateral and anterior segments of the apical views (maximum of 80%). The improved endocardial border delineation resulted in an improved agreement between two observers in the interpretation of the dobutamine stress echocardiograms as positive or negative (kappa=0.38 without contrast, kappa=0.58 with contrast). Contrast application resulted in a slight improvement of diagnostic accuracy of dobutamine stress echocardiography in the detection of angiographically proven significant coronary artery disease. Conclusion: In patients with impaired endocardial border delineation the use of the echo contrast agent BY 963 reduces the number of non-evaluable segments. Improvement of endocardial delineation is greatest for lateral and anterior segments in the apical views.
    Type of Medium: Electronic Resource
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