TY - JOUR
T1 - The influence of a shield on intense ion beam transportation
AU - Pushkarev, A. I.
AU - Isakova, Yu I.
AU - Khailov, I. P.
PY - 2013/9/1
Y1 - 2013/9/1
N2 - This article presents the results of a study on transportation of a pulse ion beam of gigawatt power. This beam is formed by a self-magnetically insulated diode with an explosive-emission cathode. The experiments have been performed using the TEMP-4M pulsed ion accelerator configured in double-pulse formation mode with the first negative pulse (300-500 ns, 100-150 kV), followed by the second positive pulse (150 ns, 250-300 kV). To increase the effectiveness of ion beam focusing, a metal shield is installed on a grounded electrode. Investigations are performed using a strip focusing diode, a cone diode, and a spiral diode with metal shields of different constructions. We observed that the beam diameter at the focus decreases from 60 mm (without shield) to 40-42 mm (with a shield), which leads to an increase in the energy density by a factor of 1.5-2 being 4-5 J/cm2 at the focus. We analyzed different mechanisms for ion trajectories deviation from an ideal one: Coulomb repulsion due to incomplete space charge neutralization, influence of electromagnetic fields, etc. It is found that for a strip focusing diode the concentration of low-energy electrons accompanying the ion beam exceeds the concentration of ions by 1.3-1.5 times. The use of a metal shield improves the transportation properties of the ion beam by keeping neutralizing electrons within the beam volume which ensures its space charge neutralization during the transport.
AB - This article presents the results of a study on transportation of a pulse ion beam of gigawatt power. This beam is formed by a self-magnetically insulated diode with an explosive-emission cathode. The experiments have been performed using the TEMP-4M pulsed ion accelerator configured in double-pulse formation mode with the first negative pulse (300-500 ns, 100-150 kV), followed by the second positive pulse (150 ns, 250-300 kV). To increase the effectiveness of ion beam focusing, a metal shield is installed on a grounded electrode. Investigations are performed using a strip focusing diode, a cone diode, and a spiral diode with metal shields of different constructions. We observed that the beam diameter at the focus decreases from 60 mm (without shield) to 40-42 mm (with a shield), which leads to an increase in the energy density by a factor of 1.5-2 being 4-5 J/cm2 at the focus. We analyzed different mechanisms for ion trajectories deviation from an ideal one: Coulomb repulsion due to incomplete space charge neutralization, influence of electromagnetic fields, etc. It is found that for a strip focusing diode the concentration of low-energy electrons accompanying the ion beam exceeds the concentration of ions by 1.3-1.5 times. The use of a metal shield improves the transportation properties of the ion beam by keeping neutralizing electrons within the beam volume which ensures its space charge neutralization during the transport.
KW - Accelerator
KW - Intense ion beams
KW - Ion beam transportation and focusing
KW - Self-magnetically insulated diode
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U2 - 10.1017/S0263034613000530
DO - 10.1017/S0263034613000530
M3 - Article
AN - SCOPUS:84884541056
VL - 31
SP - 493
EP - 501
JO - Laser and Particle Beams
JF - Laser and Particle Beams
SN - 0263-0346
IS - 3
ER -