Title :
Plasma focus as a lens for intense ion beam focusing
Author :
Belan, V.N. ; Butenko, V.I. ; Volkolupov, Y.Y. ; Ivanov, B.I. ; Kiselev, V.A. ; Krasnogolovets, M.A. ; Linnik, A.F. ; Maslov, V.I. ; Onishchenko, I.N. ; Prishchepov, V.P.
Author_Institution :
NSC "Kharkov Inst. of Phys. & Technol., Kharkov, Ukraine
Abstract :
Summary form only given, as follows. Some fundamental problems of high energy physics (beam emittance decreasing and luminosity enhancement in GeV-colliders) and technological applications (nuclear microprobe, material modification) challenge the elaboration of nonconventional schemes for ion beams focusing with plasma. The theoretical and experimental investigations of the focusing processes of the intense ion beam of MeV range energy by means of plasma focus produced with coaxial plasma gun have been carried out. Proton beam of 5 MeV energy, 100 mA current, and 30 μsec time duration was produced at the proton accelerator "Ural-5" with radio frequency quadruple (RFQ) radial-phase focusing for beam current increasing. Plasma lens was formed during plasma flow injection from a coaxial plasma gun into nonuniform magnetic field of a short coil and plasma focus arising. The parameters of the plasma were the following: plasma density 10/sup 11/-10/sup 15/ cm/sup -3/, temperature 1-3 eV, and time duration 500 μsec. The magnetic field value was 500-1000 Oe. Theoretical study and macroparticles simulation was performed to evaluate the focusing properties of the plasma focus formation. The space charge compensation and the role of the electric and magnetic fields existing in the plasma on the focusing processes have been considered. The influence of HF instabilities and polarization phenomena on ion beam focusing was estimated. Magnetic probes and optic spectroscopy diagnostics was used for temporal and spatial plasma geometry investigation. Ion beam portrait was determined at the luminescence screen. In the experiments performed the focusing coefficient was obtained as ten times beam compression at the length of 30 cm. Changing gas volume input, gun voltage, time delay, magnetic field value etc. the dependence of focused ion beam diameter upon various parameters of the plasma focus lens has been investigated. It was revealed that the main focusing effect - as caused by the azimuth magnetic field of the currents carried by the plasma.
Keywords :
focused ion beam technology; particle beam diagnostics; particle beam focusing; plasma focus; plasma probes; plasma simulation; 1 to 3 eV; 100 mA; 5 MeV; 500 mus; HF instabilities; Ion beam portrait; Ural-5 proton accelerator; azimuthal magnetic field; beam compression; beam current; beam emittance; coaxial plasma gun; electric fields; focused ion beam diameter; focusing effect; focusing processes; gas volume input; gun voltage; high energy physics; intense ion beam; intense ion beam focusing; ion beam focusing; lens; luminescence screen; luminosity enhancement; macroparticle simulation; magnetic field; magnetic fields; magnetic probes; material modification; nonuniform magnetic field; nuclear microprobe; optical spectroscopy; plasma currents; plasma density; plasma flow injection; plasma focus; plasma focus lens; plasma temperature; plasma time duration; polarization phenomena; proton beam current; proton beam energy; proton beam time duration; radio frequency quadruple radial-phase focusing; short coil; space charge compensation; spatial plasma geometry; temporal plasma geometry; time delay; Ion beams; Lenses; Magnetic fields; Particle beams; Plasma accelerators; Plasma applications; Plasma density; Plasma materials processing; Plasma simulation; Plasma temperature;
Conference_Titel :
Plasma Science, 2002. ICOPS 2002. IEEE Conference Record - Abstracts. The 29th IEEE International Conference on
Conference_Location :
Banff, Alberta, Canada
Print_ISBN :
0-7803-7407-X
DOI :
10.1109/PLASMA.2002.1030624
