The negative ions traveling down the beam tube are attracted (accelerated) towards the positive terminal.At the terminal they pass through an electron stripper, either a gas or a very thin carbon foil, and emerge as positive ions.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.This selects particles based on their energy and thus removes the ions that happen to receive the wrong energy from the accelerator.The gas ionization detector counts ions one at a time as they come down the beamline.At this point the beam is about 10 microamps which corresponds to 10 ions per second (mostly the stable isotopes).
For each atom, the computer determines the rate of energy loss and from that deduces the nuclear charge (element atomic number) to distinguish interfering isobars.
At the Laboratory, aside from modern and background standards, routine in-house measurements are also made on standards of like composition and age to the sample being dated.
Accelerator mass spectrometry (AMS) is a technique for measuring long-lived radionuclides that occur naturally in our environment.
The tandem accelerator consists of two accelerating gaps with a large positive voltage in the middle.
Think of it as a bridge that spans the inside of a large pressure vessel containing CO insulating gas at a pressure of over 10 atmospheres.
Organic samples are converted to COC using an iron catalyst.