The Dresden EBIT is a compact electron beam ion trap originally designed for x-ray spectroscopy purposes ('T' in EBIT means 'Trap' while 'S' in EBIS stands for 'Source'). Its ion trap length has a small design value of 20 mm which offers very precise control of the electron beam properties but limits the ion trap capacity resulting in lower extractable ion currents. However, the Dresden EBIT is a very cost-efficient alternative for the production of low, intermediate, and highly charged ions or molecule fragments if the ion output is not the most critical point of an application.
The functional principle of the ion source is based on a cathode of high electron emissivity generating a strong electron beam which is magnetically compressed to achieve high electron beam densities. The operation principle of the ion source allows for generation of DC beams (leaky mode) as well as pulsed ion beams. The ion pulse form can be varied from Gaussian to flat-top shapes by an additional electronic system controlling the ramping of the trap voltages during ion extraction.
Particle injection into the Dresden EBIT can be realized by different injection methods such as direct gas inlet, metal ion introduction via the gas inlet using volatile compounds (MIVoC), or by injection of low charged ions produced by Liquid Metal Alloy Ion Sources (LMAIS) or other primary ion sources (charge breeding). Therefore, the Dresden EBIT can produce charge states from low up to highly charged ions of practially any element of the periodic table.
Figure 1 - Dresden EBIT Argon Spectra
Figure 2 - Dresden EBIT Xenon Spectra
Figures 1 and 2 present several examples of extracted ion spectra. Figure 1 shows ion spectra of the intermediate-weight element argon. Figure 2 presents extracted xenon charge states of up to Xe46+. Furthermore, the following table gives an overview of ion currents which can be extracted from the source.
Ion Species
Ions / pulse
C6+ (fully ionized)
2 · 106 at 5 Hz
Ar8+ (Ne-like)
9 · 105 at 50 Hz
Ar16+ (He-like)
4 · 105 at 1 Hz
Ar18+ (fully ionized)
5 · 104 at 0.5 Hz
Fe22+ (Ne-like)
1 · 104 at 0.7 Hz
Fe24+ (He-like)
9 · 103 at 0.3 Hz
Fe25+ (H-like)
2 · 103 at 0.3 Hz
Xe44+ (Ne-like)
5 · 103 at 0.2 Hz
Xe46+
7 · 102 at 0.2 Hz
Please note: The ion output depends strongly on the ion source parameters. To achieve the highest possible ion output the source parameters need to be optimized for each ion species individually.
Parameters
Source Parameters
max. electron current
5 mA
max. electron energy
15 kV
magnet system
bakeable SmCo permanent magnets
magnetic induction on axis
250 mT
trap length
20 mm
beam emittance
< 10 mm mrad
ion pulse width
50 ns up to 100 µs
ionization factor
> 1e+21 e/cm²
General Parameters
dimensions (length x width x height)
ca. 400 mm x 300 mm x 460 mm
weight
20 kg (45 lbs)
Infrastructural Requirements
cooling water
one circuit, 1.5 l / min at 3 bar
vacuum conditions
UHV, 1e-8 mbar and better
Scope of Delivery
EBIT vacuum vessel, electron and ion optical electrodes, bakeable permanent magnet system readily installed
high voltage protection shields
power supply units for the operation of the ion source
control system including computer and software
Optional Equipment
precision gas inlet valve
Be-window for inline x-ray spectroscopy
x-ray detector
TERX - time and energy resolved x-ray detection system
heating tent incl. temperature control
19" rack for power supplies and measurement equipment
vacuum system (TMP, fine vacuum, vacuum measurement)
spare electron gun head (with 0.5 mm / 1 mm cathode)
injection kit for element injection through volatile compounds
metal ion injection kit incl. quadrupole beam bender and liquid metal ion source
small, medium or large ion beam line for ion charge state separation
