J Asada

A New Versatile Electron-Beam Ion Trap

We have constructed an electron-beam ion trap (EBIT) to facilitate the creation and study of highly charged ions. After a brief introduction to EBITs in general, we describe the design of the new device, highlighting its unique features. Some preliminary results are presented which demonstrate the devices capability to produce and study highly charged ions.

Characteristics of the Tokyo Electron-Beam Ion Trap.

We have constructed a new Electron Beam Ion Trap (EBIT). Over recent months, we have operated this device and obtained some experimental results. In this paper, we show the performance of this EBIT by illustrating these results.

An overview of the Tokyo electron beam ion trap

A new Electron Beam Ion Trap has recently been completed in Tokyo. The general features of the apparatus, design and operation are given. This paper also surveys the planned and ongoing experimental program.

The present status of the Tokyo electron beam ion trap

Recent progress of the Tokyo electron beam ion trap (Tokyo-EBIT) project is described. The Tokyo-EBIT is of an original design and construction with several features different from other EBITs in the world. The maximum energy and current of the electron beam are designed to be 340 keV and 300 mA with a magnetic field of 4.5 T. The ongoing and planned physics experiments are described and the results for the initial stage of operation of the Tokyo-EBIT are given.

Detector systems for use with an electron beam ion trap

This article describes two data systems, primarily for use with x-ray detectors in conjunction with an Electron Beam Ion Trap (EBIT). Both systems are designed from a common viewpoint that useful information should be presented in real-time whilst as much information as possible should be stored for subsequent off-line analysis.

X-ray spectroscopy at the Tokyo electron beam ion trap

We have observed x-ray signals from He-like Ba and Ne-like W ions trapped in an Electron Beam Ion Trap (EBIT) at an electron beam energy of 19.9 keV. In the spectra, several transitions in Ne-like Ba and W ions and radiative recombination processes (RR) to n ≥ 2 levels were observed. These atoms were seeded by the cathode and were ionized in the trap region by electron impact. We have observed dielectronic recombination processes (DR) in Ne-like Xe.

Extraction of trapped ions from the Tokyo electron beam ion trap

A beam line for transporting highly charged ions extracted from the Tokyo Electron Beam Ion Trap is being constructed in order to study ion-surface interactions and to inject into secondary ion traps for atomic physics experiments. A basic idea for the design and a computer modeling for the extraction system are described. The results of a test experiment to detect the total number of ions extracted from the EBIT are also reported.

Application to argon ions of a new technique to measure the two-electron contribution to the ground state energy of helium-like ions

We have measured the two-electron contribution of the ground state energy of helium-like argon ions using an electron beam ion trap (EBIT). A two-dimensional map was measured showing the intensity of x-rays from the trap passing through a krypton-filled absorption cell. The independent axes of this map were electron beam energy and x-ray energy. From this map, we deduced the two-electron contribution of the ground state of helium-like argon. This experimentally determined value (312.4±9.5 eV) was found to be in good agreement with our calculated values (about 303.35 eV) and previous calculations of the same quantity. Based on these measurements, we have shown that a ten-day absorption spectroscopy run with a super-EBIT should be sufficient to provide a new benchmark value for the two-electron contribution to the ground state of helium-like krypton. Such a measurement would then constitute a test of quantum electrodynamics to second order.

Control system of the Tokyo electron beam ion trap

We introduce the control and power supply system of the Electron Beam Ion Trap at the University of Electro-Communications, Tokyo.

A new method for nondestructively monitoring the position of a charged particle beam in real time

The design and construction of a simple new device for nondestructively monitoring the position of an electron beam is described. By modulating a small portion of the electron-beam current, changes in the amounts of charge induced on the monitor electrodes are detected as currents. These currents are related to the location of the “center of charge” of the electron beam. Calculations and experimental results which illustrate the performance of the device are reported. This device is primarily intended for use in electron-beam ion sources and traps, although it could be applied to other situations where the beam current can be modulated.