ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A compact, all-permanent-magnet, single-frequency electron cyclotron resonance (ECR) ion source with a large uniformly distributed ECR plasma volume has been designed and is presently under construction at the Oak Ridge National Laboratory. The central region of the field is designed to achieve a flat field (constant mod-B) which extends over the length of the central field region along the axis of symmetry and radially outward to form a uniformly distributed ECR plasma "volume." The magnetic field design strongly contrasts with those used in conventional ECR ion sources where the central field regions are approximately parabolic and the resulting ECR zones are "surfaces." The plasma confinement magnetic field mirror has a mirror ratio Bmax/BECR of slightly greater than 2. The source is designed to operate at a nominal rf frequency of 6 GHz. The central flat magnetic field region can be easily adjusted by mechanical means to tune the source to the resonant conditions within the limits of 5.5–6.8 GHz. The rf injection system is broadband to ensure excitation of transverse electric modes so that the rf power is largely concentrated in the resonant plasma volume which lies along and surrounds the axis of symmetry of the source. Because of the much larger ECR zone, the probability for absorption of microwave power is dramatically increased, thereby increasing the probability for acceleration of electrons, the electron temperature of the plasma, and, consequently, the "hot" electron population within the plasma volume of the source. The creation of an ECR "volume" rather than a "surface" is commensurate with higher charge states and higher beam intensities within a particular charge state. The source has also been designed so that it can be easily converted into a conventional magnetic field geometry source so that comparisons of the performances of the "volume" and "surface" forms of the source can be easily made. The design features of the source and rf injection system will be described in detail in this article. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The Holifield Radioactive Ion Beam Facility now under construction at the Oak Ridge National Laboratory will use the 25 MV tandem accelerator for the acceleration of radioactive ion beams to energies appropriate for research in nuclear physics; negative ion beams are, therefore, required for injection into the tandem accelerator. Because charge exchange is an efficient means for converting initially positive ion beams to negative ion beams, both positive and negative ion sources are viable options for use at the facility. The choice of the type of ion source will depend on the overall efficiency for generating the radioactive species of interest. Although direct-extraction negative ion sources are clearly desirable, the ion formation efficiencies are often too low for practical consideration; for this situation, positive ion sources, in combination with charge exchange, are the logical choice. The high-temperature version of the CERN-ISOLDE positive ion source has been selected and a modified version of the source designed and fabricated for initial use at the facility because of its low emittance, relatively high ionization efficiencies, and species versatility, and because it has been engineered for remote installation, removal, and servicing as required for safe handling in a high-radiation-level ISOL facility. The source will be primarily used to generate ion beams from elements with intermediate to low electron affinities. Prototype plasma-sputter negative ion sources and negative surface-ionization sources are under design consideration for generating radioactive ion beams from high-electron-affinity elements. The design features of these sources and expected efficiencies and beam qualities (emittances) will be described in this report.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1573-8248
    Keywords: Onion maggot ; Delia antiqua ; Anthomyiidae ; pesticide impact ; natural enemies ; herbicide ; insecticide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Les différences de mortalité induites par les produits phytosanitaires entreDelia antiqua et plusieurs organismes antagonistes associés à sa limitation naturelleD. platura (MEIGEN),Coenosia tigrina (F.),Entomophtora muscae (COHK) etAphaereta pallipes (SAY) ont été évaluées dans des conditions simulant celles des cultures. Les mortalités différentes dues à l'action directe ou résiduelle des produits sont décrites pour trois herbicides (Chloro-IPC, Nitrofen et CDAA), trois fongicides (Maneb, Chlorothalonil et Sulfate de Cuivre) et un insecticide (Malathion). Les taux d'application pratique recommandés de ces produits entraînent des différences hautement positives dans les niveaux de mortalité entreD. antiqua et quelques-uns de ses agents de mortalité naturelle. Le Chloro-IPC, herbicide de préplantation et de demi-saison, provoque la mortalité totale d'A. pallipes au-delà des trois jours qui constituent la période test pour les résidus. Des modifications d'orientation comportementale et des modalités de la mort des adultes deD. antiqua infestés parE. muscae ont été aussi notées chez les mouches traitées au Malathion de sorte que la dispersion des conidies était hautement réduite.
    Notes: Abstract Pesticide-induced differential mortality betweenDelia antiqua(MEIGEN)and several other organisms associated with its natural control [D. platura(MEIGEN),Coenosia tigrina (F.),Entomophtora muscae (COHN), andAphaereta pallipes (SAY)] were evaluated under simulated field conditions. Direct and residual differential mortalities were described for 3 herbicides (Chloro-IPC, nitrofen, and CDAA), 3 fungicides (maneb, chlorothalonil, and copper sulfate), and 1 insecticide (malathion). The recommended field application rates of these chemicals produced high positive differential mortality levels betweenD. antiqua and some of the natural mortality agents. Chloro-IPC, a preplant and midseason herbicide, induced 100% mortality ofA. pallipes over the 3-day residual test period. Modifications in behavioral orientation and death patterns ofD. antiqua adults infected withE. muscae were also noted in malathion-treated flies such that subsequent conidial dispersal was highly restricted.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1573-8248
    Keywords: Southwood's method ; estimation ; parasitism ; sampling ; Méthode de Southwood ; estimation ; parasitisme ; échantillonnage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Un modèle de simulation est utilisé pour examiner les erreurs dans l'estimation des densités d'hôtes parasités et non parasités indépendamment avec la technique graphique de Southwood. Cette technique est exacte quand l'attaque du parasitoïde a lieu avant la période d'échantillonnage. Quand ceci n'est pas le cas, la densité d'hôtes parasités est estimée exactement mais la densité d'hôtes non parasités est surestimée par ces individus qui sont échantillonnés comme vivants avant l'attaque. Cette erreur est négligeable aux faibles niveaux de parasitisme (〈20%), mais elle augmente avec l'accroissement du parasitisme. Des paramètres biologiques testés, seul le modèle d'attaque du parasitoïde (forme de la courbe d'attaque du parasitoïde) a une influence significative sur la valeur de cette erreur. Un modèle de simulation généralisé est présenté pour évaluer les erreurs dans l'estimation du parasitisme saisonnier pour les interactions spécifiques hôte-parasitoïde.
    Notes: Abstract A simulation model is used to examine the errors in estimating parasitized and nonparasitized host densities independently with Southwood's graphical technique. This technique is accurate when parasitoid attack occurs prior to the sampling period (e.g. the previous life stage of the host). When this is not the case, the parasitized host density is estimated accurately, but the unparasitized host density is over estimated by those individuals that are sampled as healthy prior to attack. This error is neglible at low levels of parasitism (〈20% parasitized), but increases with increasing parasitism. Of the biological parameters tested, only the parasitoid attack pattern (shape of the parasitoid attack curve) has a significant influence on the magnitude of this error. A generalized simulation model is presented for evaluating errors in estimates of seasonal parasitism for specific host-parasitoid interactions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-1254
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geography , Physics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Phytopathology 20 (1982), S. 363-395 
    ISSN: 0066-4286
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Entomology 26 (1981), S. 259-287 
    ISSN: 0066-4170
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A compact, all-permanent-magnet, single-frequency electron cyclotron resonance (ECR) ion source with a large uniformly distributed ECR plasma volume has been designed and is presently under construction at the Oak Ridge National Laboratory. The central region of the field is designed to achieve a flat field (constant mod-B) which extends over the length of the central field region along the axis of symmetry and radially outward to form a uniformly distributed ECR plasma "volume." The magnetic field design strongly contrasts with those used in conventional ECR ion sources where the central field regions are approximately parabolic and the resulting ECR zones are "surfaces." The plasma confinement magnetic field mirror has a mirror ratio Bmax/BECR of slightly greater than 2. The source is designed to operate at a nominal rf frequency of 6 GHz. The central flat magnetic field region can be easily adjusted by mechanical means to tune the source to the resonant conditions within the limits of 5.5–6.8 GHz. The rf injection system is broadband to ensure excitation of transverse electric modes so that the rf power is largely concentrated in the resonant plasma volume which lies along and surrounds the axis of symmetry of the source. Because of the much larger ECR zone, the probability for absorption of microwave power is dramatically increased, thereby increasing the probability for acceleration of electrons, the electron temperature of the plasma, and, consequently, the "hot" electron population within the plasma volume of the source. The creation of an ECR "volume" rather than a "surface" is commensurate with higher charge states and higher beam intensities within a particular charge state. The source has also been designed so that it can be easily converted into a conventional magnetic field geometry source so that comparisons of the performances of the "volume" and "surface" forms of the source can be easily made. The design features of the source and rf injection system will be described in detail in this article. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The Holifield Radioactive Ion Beam Facility now under construction at the Oak Ridge National Laboratory will use the 25-MV tandem accelerator for the acceleration of radioactive ion beams to energies appropriate for research in nuclear physics; negative ion beams are, therefore, required for injection into the tandem accelerator. Because charge exchange is an efficient means for converting initially positive ion beams to negative ion beams, both positive and negative ion sources are viable options for use at the facility. The choice of the type of ion source will depend on the overall efficiency for generating the radioactive species of interest. Although direct-extraction negative ion sources are clearly desirable, the ion formation efficiencies are often too low for practical consideration; for this situation, positive ion sources, in combination with charge exchange, are the logical choice. The high-temperature version of the CERN-ISOLDE positive ion source has been selected and a modified version of the source designed and fabricated for initial use at the facility because of its low emittance, relatively high ionization efficiencies and species versatility, and because it has been engineered for remote installation, removal and servicing as required for safe handling in a high-radiation-level ISOL facility. The source will be primarily used to generate ion beams from elements with intermediate to low ionization potentials. Prototype plasma-sputter negative ion sources and negative surface-ionization sources are under design consideration for generating radioactive ion beams from high-electron-affinity elements. The design features of these sources and expected efficiencies and beam qualities (emittances) will be described in this report.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Beam from the accelerator for research was available for a total period of 3900 h last year and unscheduled maintenance time was reduced by a factor of almost 2. An arc discharge tube conditioning test was conducted on the top five units of the accelerator and a test with macropulsed beam was accomplished. The main problems during the year were vacuum leaks and voltage "tics.''
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...