Pencil-like mm-size electron beams produced with linear inductive voltage adders

Abstract

radius segments correspond to MITL sections without axial electric field. This design assures constant current flow over the entire length of SABRE. The cathode electrode is 9.6-m long and includes the voltage adder (6-m long) and a constant radius (2.2 cm) extension 3.2 m in length. We present the design, analysis, and first results of the high brightness electron beam experiments currently under investigation at Sandia National Laboratories. The anticipated beam parameters are the following: energy 12 MeV, current 35-40 kA, rms radius 0.5 mm, and pulse duration 40 ns FWHM. The accelerator is SABRE [I], a pulsed LNA modified to RADLAC 11. To generate beams of millimeter sizes, the diode must be immersed in solenoidal fields of 20-30 Tesla [5,6,7]. Figure 2 shows a schematic diagram of the diode design, including the solenoidal magnet. The shape of the fringe field is tailored by a 2-cm thick a l e n u m cylinder 25-cm iflner radius coaxially enclosing the entire diode assembly.

Coupled particle-in-cell and Monte Carlo transport modeling of intense radiographic sources

“…1,2 A number of diode configurations are being investigated as radiographic sources, 3 including the rod-pinch, 4 -8 immersed-B, 9 and paraxial 10 diodes. All of these sources are designed such that an intense electron beam strikes a small radius (р1 mm͒, high-atomic-number bremsstrahlung converter.…”

Evaluation of Self-Magnetically Pinched Diodes up to 10 MV as High-Resolution Flash X-Ray Sources

“…This is accomplished by (4) where is the total charge transferred in the diode (i.e., the integral of the diode current including both electron and ion current), is the number of passes the electrons make in the high-target, defined as the ratio of incident electron charge to absorbed electron charge, and is the ion-current fraction. The quantities and are obtained from LSP (see Fig.…”

“…The immersed-B diode uses an external 10-50-T magnetic field to guide electrons emitted from a millimeter-sized cathode needle onto a high-atomic-number (high-) target where an intense X-ray source is formed [4]- [6]. In the paraxial diode, electrons are electrostatically accelerated onto and through a thin, low-mass anode foil.…”

Immersed-B<inf>z</inf> diode research on RITS at Sandia

“…4 5 Continued development of these sources is being pursued, with emphasis on increasing the x-ray source intensity through higher end-point voltage and/or higher electron beam current, and reducing the diameter of the electron beam focal spot/x-ray source diameter. One such source is the immersed-B z diode 6 which is a foil-less electron-beam diode with a long, thin, needle-like cathode inserted into the bore of a solenoid. The magnetic field of the solenoid guides the electron beam emitted from the cathode to the anode while maintaining a small beam radius roughly that of the cathode tip.…”