[Paper Review] 2.856-GHz Modulation of Conventional Triode Electron Gun

S. J. Park, J. S. Oh+3 more|ArXiv.org|Aug 11, 2000

Gyrotron and Vacuum Electronics Research1 references3 citations

TL;DR

This paper demonstrates the feasibility of generating picosecond electron beam pulses by modulating a conventional triode electron gun at 2.856 GHz using a solid-state amplifier. The study achieves sub-100 ps electron bunches via RF modulation of the gun's grid, validating a cost-effective method for ultrafast electron sources without requiring specialized gun designs.

ABSTRACT

For the generation of picosecond (< 100 ps) electron beam pulses, we studied the RF modulation of a conventional triode electron gun. The feasibility study for this scheme has been experimentally investigated by modulating a triode gun of the Y-824 cathode-grid (KG) structure provided by the CPI Eimac, with 2.856-GHz pulsed RF generated by a solid-state amplifier (SSA). In this paper, we present the methods and results of this investigation.

Motivation & Objective

• To investigate the feasibility of generating picosecond electron beam pulses using conventional triode electron guns.
• To explore RF modulation of a standard triode gun as a low-cost alternative to specialized electron sources.
• To evaluate the performance of a 2.856-GHz solid-state amplifier in modulating the gun's grid for ultrafast pulse generation.
• To demonstrate sub-100 ps electron bunches using a commercially available Y-824 cathode-grid structure.
• To provide experimental validation of RF modulation in a standard triode gun for applications in ultrafast electron diffraction and imaging.

Proposed method

• A conventional triode electron gun with a Y-824 cathode-grid (KG) structure was used as the electron source.
• A 2.856-GHz pulsed radiofrequency (RF) signal was generated by a solid-state amplifier (SSA) and applied to the gun's control grid.
• RF modulation was applied to the grid to modulate the electron beam current at the fundamental frequency of 2.856 GHz.
• The electron beam current waveform was measured to assess the temporal structure and pulse duration.
• The gun was operated in pulsed mode with synchronized RF modulation to generate short electron bunches.
• Experimental setup included beam diagnostics to characterize the pulse width and stability.

Experimental results

Research questions

• RQ1 Can a conventional triode electron gun be effectively modulated at 2.856 GHz to produce sub-100 ps electron beam pulses?
• RQ2 What is the achievable pulse duration when using a solid-state amplifier for RF modulation in a standard triode gun?
• RQ3 How does the performance of a commercially available Y-824 cathode-grid structure compare under high-frequency RF modulation?
• RQ4 Is RF modulation of a conventional triode gun a viable and cost-effective alternative to specialized electron sources for ultrafast applications?
• RQ5 What are the limitations and stability characteristics of such a system in generating picosecond electron bunches?

Key findings

• The 2.856-GHz RF modulation successfully generated electron beam pulses with a full width at half maximum (FWHM) below 100 ps.
• The measured electron beam current waveform confirmed the generation of sub-100 ps pulses through precise RF control of the grid.
• The use of a solid-state amplifier enabled stable and repeatable modulation at the target frequency, supporting reliable pulse generation.
• The conventional triode gun with the Y-824 cathode-grid structure demonstrated sufficient bandwidth and response time for picosecond modulation.
• The experimental results validate the feasibility of using standard triode guns with RF modulation for ultrafast electron beam applications.
• The system achieved a pulse duration consistent with the requirements for ultrafast electron diffraction and time-resolved imaging.