In 1939, UC Berkeley scientists Luis Alvarez and Robert Cornog were the first to use AMS in the detection of Now, over 70 years later, cyclotrons have been replaced by an accelerator type with greater energy stability: the tandem electrostatic accelerator.An electrostatic accelerator works by accellerating particles though a magnetic field generated by high voltages using a mechanic transport system that continuously transports charges from ground to the insulated high-voltage terminal.The Van de Graaff accelerator removes at least four electrons.It is preferrable to remove at least three electrons because by this process that molecular isobars of The negative ions are changed to positively charged ions and are thus accelerated back to the ground potential in the high-energy part of the accelerator.In all tandem accelerators, atoms are stripped at the high-voltage terminal using either a thin Carbon foil or Argon gas.Stripping is the process in which two or more electrons are removed.
The negative ions that enter the accelerator are attracted to the high-voltage terminal, which is what accellerates the CAMS LLNL employs a tandem Van de Graaff accelerator, in which a second acceleration of millions of volts is applied.
The sample is held at a negative potential, and negatively charged ions are accelerated away from the sample, resulting in a beam of negative ions (Figure 2, below). The low energy (~5-10 ke V) diverging beam that leaves the ion source is accelerated, focused and transported to the accelerator by the injector system. Most AMS systems use sequential injection, a process that switches between stable and rare isotopes via the application of varying voltages to the electrically insulated vacuum chamber of the analyzer magnet.
Cs It is important to have a beam of negative ions entering the accelerator because the negative ions are attacted to the high -voltage terminal which results in their net acceleration. In sequential injection, typical injection repetition rates are 10 sec C analysis.
These two pieces of information are sufficient to completely identify the ion as C atoms at the rate at which they decay.
This requires sufficient atoms to be present to provide a large enough decay rate, as described above.
A recombinator is used following sequential injection, which is a sequence of magnetic analyzers and quadrupole lenses that focus the stable and rare isotopes so they recombine and enter the accelerator together.