The maximum achievable electron beam current depends on the drift tube voltage, but usually is around 150 mA. In the super-EBIT at Lawrence Livermore National Laboratory, the electron beam energy can extend beyond 200,000 eV.
The maximum electron beam energy is determined by the positive voltage bias applied to the drift tubes (basically a set of three cylindrical copper tubes) and can range from about 700 eV to over 30,000 eV in the NIST EBIT. The electron beam is decelerated and finally extinguished at a cooled copper electrode called the collector. The primary component of the EBIT is the electron beam, which is formed in a commercial Pierce-type gun and is guided, accelerated and focused by several magnetic coils and high voltage electrodes. Typically, a wide range of low and high resolution spectrometers are employed, including Bragg crystal x-ray spectrometers and solid state silicon and germanium detectors.
#Charge of electron nist windows#
The radiation is viewed through side windows at 90 degrees to the electron beam direction. One of the primary ways of studying the ions in an EBIT is spectroscopy, which involves observing and analyzing the radiation (usually x-ray) emitted by the ions after collisional excitation by the electrons from the beam. At Lawrence Livermore National Laboratory (LLNL), researchers recently used a high energy version of the EBIT called Super-EBIT to create fully-stripped uranium (92+). We have run our EBIT at electron beam energies up to 33 kV which is theoretically enough to produce charge states as high as U90+.
Here at NIST, we have produced and recorded x-ray spectra from charge states as high as Bi73+, which corresponds to the neon-like state (only ten electrons remain). Virtually any charge state of any element in the periodic table can be studied using an EBIT simply by injecting the desired element and adjusting the electron beam energy appropriately. The electron beam ion trap (EBIT) is a small-scale laboratory instrument which uses a tightly focused and energy-tunable electron beam to create, trap, and probe highly charged ions.
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