Injection of Gases by Controlled Ultra-High Vacuum All-Metal Valve
The easiest way of injecting an element into an ion source is having this element as a gas (e.g. nitrogen, oxygen or noble gases like helium, argon or xenon) or as part of a gaseous molecule (e.g. carbon in a hydrocarbon like propane or methane). This gases are available bottled and can be injected by an ultra-high vacuum all-metal valve. An external controller with a PID control provides the desired pressure in an easy and reliable way.
Injection of Metals and other Elements from Volatile Compounds (MIVOC)
Some volatile metal organic compounds can be used to inject metal atoms into the ion source. These organic substances contain only carbon, hydrogen and/or oxygen along with metal atoms. These compounds, such as metalocenes, hexacarbonyl, or tetramethyl, have a high vapour pressure and thus evaporate easily at room temperature. The metal organic substances are placed in a separate vacuum chamber which is connected to a all-metal valve. The low evaporation pressure of these compounds allows admitting them as gases into the ion source.
The term MIVOC (Metal Ions from Volatile Compounds) suggests this method would be suitable only for metals, but it works for other elements as well: The MIVOC System features the injection of silicon, phosphorus, titanium, manganese, iron, nickel, zinc, germanium, tin, tungsten, magnesium, cobalt, chrome, molybdenum, ruthenium, antimony, tellurium, osmium...
Metalocene molecule (C5H5)2Metal
used to supply the trap with ions such as iron and nickel
Tetramethyl molecule (CH3)4Metal
used to supply the trap with ions such as tin and germanium
Injection of Metal Ions by an External Ion Source and a Quadrupole Beam Bender
Single charged ions can be produced by an external ion source (for example a Liquid Metal Ion Source) and injected by a quadrupole beam bender into an EBIS for charge breeding to higher ionization states (as demonstrated in the Figure for gold ions). Ion Injection is possible for many of the ions, a Liquid Metal Ion Source can produce (not only metals!), e.g. gold, bismuth, germanium, erbium, indium, caesium, antimony, platinum, praseodymium and other...
Charge Breeding with Dresden EBIS/T systems has been demonstrated by:
A. Thorn, A. Sokolov, G. Vorobyev, F. Herfurth, O. Kester, W. Quint, F. Ullmann and G. Zschornack
GSI SCIENTIFIC REPORT 2009, INSTRUMENTS-METHODS-52, p.332