Electron beam ion trap
Encyclopedia
Electron beam ion trap is used in physics to denote an electromagnetic
bottle that produces and confines highly charged ion
s.
It was invented by M. Levine and R. Marrs at LLNL and LBNL.
An EBIT uses an electron beam focused by means of a powerful magnetic field to ionize (see Ionization
) by repeated electron
impact atoms injected into the apparatus to very high charge states. The vacuum
device requires intense electron beam currents of tens up to hundreds of milliamps accelerated by means of high voltages (up to 200,000 V) applied to special electrode
s. The positive ions produced in the region where the atoms intercept the electron beam are tightly confined in their motion by the strong attraction exerted by the negative charges flowing in the electron beam. Therefore, their paths orbit around the electron beam crossing it frequently, thus giving rise to further collisions and continued ionization
. To keep their motion restricted in the direction of the electron beam axis, trapping electrodes carrying positive voltages with respect to the central electrode are used. The resulting ion trap
can hold the ions for many seconds and minutes, and conditions for reaching the highest charge states, up to bare uranium (U92+) are achieved in this way. To avoid spoiling the produced ions by collisions with neutral atoms from which they can capture electrons, the vacuum in the apparatus is usually maintained at UHV
levels, with typical pressure values of only 10-12 torr, (or ~10−10 pascal
).
EBITs are used to investigate the fundamental properties of highly charged ion
s e. g. by photon spectroscopy
in particular in the context of relativistic
atomic structure theory and quantum electrodynamics
(QED). Their suitability to prepare and reproduce in a microscopic volume the conditions of high temperature astrophysical plasma
s and magnetic confinement fusion
plasmas make them very appropriate research tools. Other fields include the study of their interactions with surfaces and possible applications to microlithography.
Electromagnetism
Electromagnetism is one of the four fundamental interactions in nature. The other three are the strong interaction, the weak interaction and gravitation...
bottle that produces and confines highly charged ion
Highly charged ion
Highly charged ions are ions in very high charge states due to the loss of many or most of their bound electrons by energetic collisions or high-energy photon absorption. Examples are 13-fold ionized iron , found in the Sun's corona, or naked uranium , bare all bound electrons, which requires very...
s.
It was invented by M. Levine and R. Marrs at LLNL and LBNL.
An EBIT uses an electron beam focused by means of a powerful magnetic field to ionize (see Ionization
Ionization
Ionization is the process of converting an atom or molecule into an ion by adding or removing charged particles such as electrons or other ions. This is often confused with dissociation. A substance may dissociate without necessarily producing ions. As an example, the molecules of table sugar...
) by repeated electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
impact atoms injected into the apparatus to very high charge states. The vacuum
Vacuum
In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...
device requires intense electron beam currents of tens up to hundreds of milliamps accelerated by means of high voltages (up to 200,000 V) applied to special electrode
Electrode
An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit...
s. The positive ions produced in the region where the atoms intercept the electron beam are tightly confined in their motion by the strong attraction exerted by the negative charges flowing in the electron beam. Therefore, their paths orbit around the electron beam crossing it frequently, thus giving rise to further collisions and continued ionization
Ionization
Ionization is the process of converting an atom or molecule into an ion by adding or removing charged particles such as electrons or other ions. This is often confused with dissociation. A substance may dissociate without necessarily producing ions. As an example, the molecules of table sugar...
. To keep their motion restricted in the direction of the electron beam axis, trapping electrodes carrying positive voltages with respect to the central electrode are used. The resulting ion trap
Ion trap
An ion trap is a combination of electric or magnetic fields that captures ions in a region of a vacuum system or tube. Ion traps have a number of scientific uses such as mass spectrometery and trapping ions while the ion's quantum state is manipulated...
can hold the ions for many seconds and minutes, and conditions for reaching the highest charge states, up to bare uranium (U92+) are achieved in this way. To avoid spoiling the produced ions by collisions with neutral atoms from which they can capture electrons, the vacuum in the apparatus is usually maintained at UHV
UHV
UHV may refer to:* University of Houston–Victoria* Ultra high vacuum* Ultra high voltage power line...
levels, with typical pressure values of only 10-12 torr, (or ~10−10 pascal
Pascal (unit)
The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...
).
EBITs are used to investigate the fundamental properties of highly charged ion
Highly charged ion
Highly charged ions are ions in very high charge states due to the loss of many or most of their bound electrons by energetic collisions or high-energy photon absorption. Examples are 13-fold ionized iron , found in the Sun's corona, or naked uranium , bare all bound electrons, which requires very...
s e. g. by photon spectroscopy
Spectroscopy
Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...
in particular in the context of relativistic
Theory of relativity
The theory of relativity, or simply relativity, encompasses two theories of Albert Einstein: special relativity and general relativity. However, the word relativity is sometimes used in reference to Galilean invariance....
atomic structure theory and quantum electrodynamics
Quantum electrodynamics
Quantum electrodynamics is the relativistic quantum field theory of electrodynamics. In essence, it describes how light and matter interact and is the first theory where full agreement between quantum mechanics and special relativity is achieved...
(QED). Their suitability to prepare and reproduce in a microscopic volume the conditions of high temperature astrophysical plasma
Astrophysical plasma
An astrophysical plasma is a plasma the physical properties of which are studied as part of astrophysics. Much of the baryonic matter of the universe is thought to consist of plasma, a state of matter in which atoms and molecules are so hot, that they have ionized by breaking up into their...
s and magnetic confinement fusion
Magnetic confinement fusion
Magnetic confinement fusion is an approach to generating fusion power that uses magnetic fields to confine the hot fusion fuel in the form of a plasma. Magnetic confinement is one of two major branches of fusion energy research, the other being inertial confinement fusion. The magnetic approach is...
plasmas make them very appropriate research tools. Other fields include the study of their interactions with surfaces and possible applications to microlithography.