Zobrazeno 1 - 10
of 96
pro vyhledávání: '"J. H. Whealton"'
Autor:
J. H. Whealton, Anatoli V. Melechko, V. I. Merkulov, D. H. Lowndes, Larry R. Baylor, E. D. Ellis, Michael L. Simpson, Michael A. Guillorn
Publikováno v:
Journal of Applied Physics. 91:4602-4606
Field emission from isolated individual vertically aligned carbon nanocones (VACNCs) has been measured using a small-diameter moveable probe. The probe was scanned parallel to the sample plane to locate the VACNCs, and perpendicular to the sample pla
Autor:
C. Deniset, M. Bacal, L. I. Elizarov, A. M. Bruneteau, F. Sube, A. Y. Tontegode, J. H. Whealton
Publikováno v:
Review of Scientific Instruments. 71:1082-1085
It is well known that cesium seeding in volume hydrogen negative ion sources leads to a large reduction of the extracted electron current and in some cases to the enhancement of the negative ion current. The cooling of the electrons due to the additi
Autor:
Anatoli V. Melechko, J. H. Whealton, Michael L. Simpson, Vladimir I. Merkulov, D. H. Lowndes, R. J. Raridon, Michael A. Guillorn
Publikováno v:
Applied Physics Letters. 80:4816-4818
Controlled alignment of catalytically grown carbon nanofibers (CNFs) at a variable angle to the substrate during a plasma-enhanced chemical vapor deposition process is achieved. The CNF alignment is controlled by the direction of the electric field l
Autor:
J. H. Whealton, C. C. Tsai, H. H. Haselton, W. K. Dagenhart, M. A. Akerman, J. J. Donaghy, W. L. Stirling, W. R. Becraft, D. E. Schechter
Publikováno v:
Review of Scientific Instruments. 61:783-787
The emittances of hydrogen and deuterium negative ion beams produced by volume ion sources have been measured in a transverse plane normal to the beam trajectory. The extraction voltage was varied from 10 to 40 kV, and the transverse magnetic field i
Publikováno v:
Review of Scientific Instruments. 69:1158-1160
Publikováno v:
Review of Scientific Instruments. 69:1103-1105
A negative-ion source extraction model has been formulated and implemented that explicitly considers the motion of positive ions and the volume generation of negative ions. It is found that (1) for high-beam currents, the beam current is limited by a
Autor:
J. H. Whealton
Publikováno v:
Encyclopedia of Applied Physics
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::f1f4e947f7c6e50fa22ca2dfe12955d5
https://doi.org/10.1002/3527600434.eap603
https://doi.org/10.1002/3527600434.eap603
Publikováno v:
Scopus-Elsevier
The best features of two independently developed surface-plasma negative ion sources with separated function (independently controlled plasma generation and negative ion emission), have been combined in an optimized configuration; as a result, we pro
Publikováno v:
Review of Scientific Instruments. 61:436-438
Nonlinear emittance growth produced by ion extraction is considered by a 3‐D analysis in a Vlasov–Poisson–Boltzmann formulation. Phenomena considered include (1) presheath effects, including electron depletion, (2) electron sheath accumulation
Publikováno v:
Review of Scientific Instruments. 61:568-570
rms emittance growth of liquid‐metal ion sources is studied. Processes included are nonlinear expansion through extractor and accelerator fringe fields, nonlinear beam space charge, plasma effects near needle, and waves [either ion acoustic or spac