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Atoms are sputtered from the sample by cesium ions which are produced on a hot spherical ionizer and focused to a small spot on the sample.
Negative ions produced on the surface of the sample are extracted from the ion source and sent down the evacuated beam line towards the first magnet.
For example: C has long been used as a tracer for chemical processes and pathways, the amount of tracer required using decay counting can be hazardous to the researchers, pose contamination problems or, in some cases, itself influence the process being studied.
At this point the beam is about 10 microamps which corresponds to 10 ions per second (mostly the stable isotopes).
The injector magnet bends the negative ion beam by 90 to select the mass of interest, a radioisotope of the element inserted in the sample holder, and reject the much-more-intense neighboring stable isotopes.
Several vacuum pumps remove all the air from the beamline so the beam particles have a free path.
There are still lots of molecules and isobars (isotopes of neighboring elements having the same mass) that must be removed by more magnets after the accelerator.
At the terminal they pass through either a very thin carbon film or a tube filled with gas at low pressure (the stripper), depending on the particular accelerator.
Collisions with carbon or gas atoms in the stripper remove several electrons from the carbon ions, changing their polarity from negative to positive. The positive ions are then accelerated through the second stage of the accelerator, reaching kinetic energies of the order of 10 to 30 million electron volts. This problem is solved in the tandem accelerator at the stripper –if three or more electrons are removed from the molecular ions the molecules dissociate into their component atoms. The kinetic energy that had accumulated up to now is distributed among the separate atoms, none of which has the same energy as a single C from the more intense "background" caused by the dissociated molecules on the basis of their kinetic energy.
The ion source produces a beam of ions (atoms that carry an electrical charge) from a few milligrams of solid material.
The element is first chemically extracted from the sample (for example, a rock, rain water, a meteorite) then it is loaded into a copper holder and inserted into the ion source through a vacuum lock.
The bridge holds two long vacuum tubes with many glass (electrically insulating) sections.
The center of the accelerator, called the terminal, is charged to a voltage of up to 10 million volts by two rotating chains.
A small sample size may or may not be a decisive advantage in a particular case, depending on the task and the nature of the sample material.Tags: Adult Dating, affair dating, sex dating