Kingdon Trap

Report
Kingdon Trap
Hande Akbas
Kealan Naughton
Alexander Fuchs-Fuchs
Kingdon Trap
Kingdon Trap with
SIMION
• Create a working Kingdon trap in
SIMION
• Results - Energy range of potentially
trapped particles
• Improvements
What is a Kingdon Trap?
• One of the first ion traps
• Radial trapping - two concentric
cylinders with potential difference
• Axial trapping -ends with higher
potential
• Ions are trapped in stable orbits if they
possess the right angular momentum
• Static applied voltage results in a radial
logarithmic potential between the
electrodes
How it works
• Static applied voltage results in a radial
logarithmic potential between the
electrodes
• Ions pulled in elliptical orbits
The Kingdon Trap
• Symmetrical device
• Inner cylinder a wire
• Outer cylinder a hollow tube
• Put caps on the ends
Theory
• Maximum and minimum energies
defined by maximum and minimum
orbits
• Energy Max: 768 eV
• Energy Minimum: 43 eV
The Trap
• Outer cylinder radius: 50 mm
• Length: 300 mm
• Inner cylinder: 5mm
• The end caps separated by a few mm
SIMION steps
• Build the Geometry
• Fly the first particles
Getting the particles
inside
• Problem: Sealed cylinder
• Make injection point
• This addition must be kept same
potential as caps and outer cylinder, for
uniform distribution
Getting the particles
inside
In action
Defining the energy
range
• Energy
• Too High: Collide with
outer cylinder
• Too Low: Collide with
inner rod
What we found
• Inner rod Potential: -3200 V
• Caps and cylinder: 20 V
• Minimum energy: 43 eV (38 eV)
• Max energy: 580 eV (768 eV)
• Mass independent
Improvements
• Never been reported to produce mass
spectra
• Modified version - Orbitrap - used as a
mass spectrometer
Orbitrap
• Type of mass spectrometer
• outerbarrel-like electrode and coaxial
inner spindle like electrode
• Electric field: quadro-logarithmic
potential distribution
Orbitrap
• Oscillation frequency: independent of
ion velocity, Inversely proportional to
square root. Characteristic of the mass
of the particle
• High accuracy: 1-2 ppm
• High resolving power: 200,000
• resolving power proportional to the
number of harmonic oscillations
Conclusions
• Simulation of a working ion trap
• Defined energy range agrees with
theory
• Upgrades can be made into a working
mass spectrometer
Don’t get Caught

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