TY - JOUR
T1 - Investigation of the homogeneity of a high-power ion beam formed by a diode with a closed electron drift
AU - Pushkarev, A. I.
AU - Yu, Xiao
PY - 2016/9/1
Y1 - 2016/9/1
N2 - The results of an investigation of the energy-density distribution over the cross section of a pulsed ion beam formed with a passive-anode diode in the mode of magnetic insulation and a closed electron drift in the anode–cathode gap are presented. Diodes of two types are studied: with external magnetic insulation (Br diode) on the BIPPAB-450 accelerator (400 kV, 80 ns) and self-magnetic insulation of electrons (spiral diode) on the TEMP-4M accelerator (250 kV, 120 ns). In the investigated diodes, various processes are used to form anode plasma: a breakdown over the surface of a dielectric coating on the anode and ionization of the anode surface with accelerated electrons (Br diode), as well as explosive emission of electrons (spiral diode). To analyze the ion-beam energy density, thermal-imaging diagnostics is used with a spatial resolution of 1–2 mm. The energy-density is calculated from the one-dimensional Child–Langmuir relationship. It is shown that a continuous plasma layer is efficiently formed on the working anode surface for all the investigated diodes. The anode-plasma concentration is rather high, and the beam-energy density is limited by the space charge of ions, but not by the plasma concentration. It is found that, when the magnetic field in the Br-diode anode–cathode gap decreases or the electron current in the spiral diode increases, the energy density of the high-power ion beam rises significantly, but the beam homogeneity decreases.
AB - The results of an investigation of the energy-density distribution over the cross section of a pulsed ion beam formed with a passive-anode diode in the mode of magnetic insulation and a closed electron drift in the anode–cathode gap are presented. Diodes of two types are studied: with external magnetic insulation (Br diode) on the BIPPAB-450 accelerator (400 kV, 80 ns) and self-magnetic insulation of electrons (spiral diode) on the TEMP-4M accelerator (250 kV, 120 ns). In the investigated diodes, various processes are used to form anode plasma: a breakdown over the surface of a dielectric coating on the anode and ionization of the anode surface with accelerated electrons (Br diode), as well as explosive emission of electrons (spiral diode). To analyze the ion-beam energy density, thermal-imaging diagnostics is used with a spatial resolution of 1–2 mm. The energy-density is calculated from the one-dimensional Child–Langmuir relationship. It is shown that a continuous plasma layer is efficiently formed on the working anode surface for all the investigated diodes. The anode-plasma concentration is rather high, and the beam-energy density is limited by the space charge of ions, but not by the plasma concentration. It is found that, when the magnetic field in the Br-diode anode–cathode gap decreases or the electron current in the spiral diode increases, the energy density of the high-power ion beam rises significantly, but the beam homogeneity decreases.
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U2 - 10.1134/S0020441216040229
DO - 10.1134/S0020441216040229
M3 - Article
AN - SCOPUS:84988876334
VL - 59
SP - 678
EP - 687
JO - Instruments and Experimental Techniques
JF - Instruments and Experimental Techniques
SN - 0020-4412
IS - 5
ER -