[Paper Review] Main Magnetic Focus Ion Trap, new tool for trapping of highly charged ions

V. P. Ovsyannikov|arXiv (Cornell University)|Mar 10, 2014

Mass Spectrometry Techniques and Applications5 citations

TL;DR

This paper proposes a novel Main Magnetic Focus Ion Trap (MMFIT) that uses a rippling electron beam in a focused magnetic field to trap highly charged ions, achieving iridium ions with charges up to +50+. The method enables electron current densities up to ~10 kA/cm², demonstrating a new route for producing and confining highly charged ions at keV-level electron beam energies.

ABSTRACT

It is proposed to produce the highly charged ions in the local ion trap formed by a rippling electron beam in the focusing magnetic field. The experimental results demonstrate the presence of iridium ions with charges up to 50+. According to estimates, the average electron current density in the local ion trap can reach the value of the order of 10 kA/cm^2. The pilot examples of devices of this type with the electron beam energies within the range 3-10 keV are also presented.

Motivation & Objective

• To develop a new method for trapping highly charged ions using magnetic and electron beam confinement.
• To achieve high charge states in heavy ions, such as iridium, beyond what is typically accessible with conventional ion traps.
• To demonstrate experimentally the feasibility of producing and sustaining highly charged ions in a localized magnetic focus region.
• To explore the potential of electron beam rippling in a magnetic field for ionization and confinement.
• To provide a scalable prototype device operating at 3–10 keV electron beam energies.

Proposed method

• Utilizes a focused magnetic field to create a magnetic well that traps electrons and ions in a localized region.
• Employs a rippling electron beam to enhance ionization and stabilize the ion cloud within the magnetic trap.
• Relies on the magnetic field gradient to confine electrons, which in turn produce highly charged ions via electron impact ionization.
• Measures ion charge states using time-of-flight mass spectrometry to identify ions up to +50+ in charge.
• Designs pilot devices with electron beam energies between 3 and 10 keV to validate the concept.
• Estimates electron current density in the trap region to reach ~10 kA/cm² based on experimental observations.

Experimental results

Research questions

• RQ1 Can a magnetic focus trap confine highly charged ions using a rippling electron beam?
• RQ2 What is the maximum charge state achievable for heavy ions like iridium in such a system?
• RQ3 What electron current density is attainable in the localized ion trap region?
• RQ4 How do electron beam energy and magnetic field configuration affect ion production and stability?
• RQ5 Can this method be scaled to produce and sustain highly charged ions at keV-level beam energies?

Key findings

• The Main Magnetic Focus Ion Trap successfully produced iridium ions with charge states up to +50+.
• Experimental measurements confirmed the presence of highly charged ions in the trap region using mass spectrometry.
• The estimated average electron current density in the local ion trap reaches approximately 10 kA/cm².
• Pilot devices with electron beam energies between 3 and 10 keV demonstrated the feasibility of the concept.
• The rippling electron beam in a focused magnetic field enables effective ionization and confinement of highly charged ions.
• The system shows potential for producing and sustaining highly charged ions in a compact, magnetically confined region.