The Dresden EBIS-A is an electron beam ion source able to produce ions of high charge states of practically all elements of the periodic table. It delivers beams of protons, alpha-particles, various highly charged ion species, as well as molecular fragments.
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 pulsed ion beams as well as DC beams (leaky mode).
Particle injection into the Dresden EBIS-A 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 Ion Sources (LMIS) or other primary ion sources (charge breeding).
The length of the extracted ion pulses has a range from 20 ns up to 100 µs. The pulse shape can be varied from Gaussian up to flat-top shapes by an additional electronic system controlling the ramping of the trap voltages during ion extraction.
Next to its use as a source for ion extraction, the trapped ions interacting with the electron beam inside the machine are a useful source of x-rays observable through optional spectroscopic ports.
Figure 1 - Argon spectrum extracted from the Dresden EBIS-A
Figure 2 - Gold ion spectrum measured at the Dresden EBIS-A
Figure 1 and Figure 2 represent two examples of extracted ion spectra from the Dresden EBIS-A. Figure 1 is an ion spectrum of the intermediate-weight element argon showing that up to fully ionized Ar18+ can be produced. The other spectrum, Figure 2, presents extracted gold charge states of up to Au60+. Furthermore, the following table gives an overview of ion currents which can be extracted from the source.
Ion Species
Ions / s (DC)
Ions / pulse
H+ (fully ionized)
2 · 1010
1 · 108 at 100 Hz
H2+
2 · 1010
He2+ (fully ionized)
6 · 108
C4+ (He-like)
6 · 108 at 2 Hz
C6+ (fully ionized)
6 · 107 at 2 Hz
Ar+
2 · 109
Ar8+ (Ne-like)
2 · 108
1 · 107 at 10 Hz
Ar16+ (He-like)
7 · 106 at 1 Hz
Ar18+ (fully ionized)
1 · 105 at 1 Hz
Fe16+ (Ne-like)
3 · 106 at 17 Hz
Fe24+ (He-like)
6 · 105 at 0.3 Hz
Fe26+ (fully ionized)
1 · 105 at 0.3 Hz
Kr26+ (Ne-like)
2 · 106
Xe44+ (Ne-like)
3 · 105 at 0.2 Hz
Au51+ (Ni-like)
5 · 105 at 1.4 Hz
Au60+
1 · 104 at 0.4 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
200 mA
max. electron energy
20 keV
magnet system
bakeable NdFeB permanent magnets
magnetic induction on axis
600 mT
trap length
60 mm
beam emittance
< 10 mm mrad
ion pulse width
50 ns up to 100 µs
ionization factor
> 1e+22 e/cm²
General Parameters
dimensions (length x width x height)
ca. 640 mm x 400 mm x 605 mm
weight
125 kg (275 lbs) with magnets
Infrastructural Requirements
cooling water
one circuit, 1.5 l / min at 3 bar
vacuum conditions
UHV, 1e-8 mbar and better
Scope of Delivery
EBIS-A 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 / 1.5 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