Multiple Isotope AMS Systems

NEC XCAMS System

NEC XCAMS System

NEC UAMS System

NEC UAMS System

Previous Next

1. 
2. 
3. 
4. 

Experience

NEC began building AMS systems over 30 years ago and is one of the premier manufacturers of AMS systems in the world. Of the more than 55 AMS systems provided to customers, the majority are studying carbon, beryllium, and aluminum in the fields of Archaeology, Geology, Groundwater analysis, Metabolite profiling, Microdosing, Atmospheric sciences, Oceanography, Nuclear waste management, Toxicology, Cosmogenic study, Astrophysics, Pharmacokinetics, and many more.

NEC offers the eXtended Compact Accelerator Mass Spectrometer (XCAMS) and Universal Accelerator Mass Spectrometer (UAMS) systems for multiple isotope AMS. The NEC XCAMS is based around a 0.500 MV tandem Pelletron for beam energies around 1 MeV. The NEC UAMS is based around a 1 MV tandem Pelletron for beam energies around 2 MeV.

Both systems are optimized for world-class precision, superb throughput, and low background of common AMS samples. The NEC Multiple Isotope AMS Systems are complete systems with all necessary hardware and software for both on-line and off-line isotope measurements.

Design

Once a sample has been appropriately processed and inserted into the ion source (either as graphite or CO₂), the sample is converted to negative ions and is accelerated through the first bending magnet. This first mass spectrometer has a biased chamber to allow sequential injection of the negative ions of interest, allowing low energy ¹²C- and ¹³C- to be measured in offset Faraday cups. As the negative ions exit the magnet, they accelerate to higher potential energy (around 0.500 MeV for the XCAMS, around 1 MV for the UAMS) into a gas stripper that breaks up negative molecules and converts the resulting single nuclei ions to positive ions. In this way, such ions as ¹²CH-, ¹²CH2-, ¹³CH-, and others are converted to single nuclei ions, ¹²C+, ¹³C+, and ¹⁴C+. This eliminates interferences that might be caused by molecular ions when counting ¹⁴C+ ions later in the system. These positive ions are then accelerated again to ground potential to the entrance of the second mass spectrometer, resulting in an improved mass separation, allowing the abundant isotopes ¹²C+ and ¹³C+ to be measured with high precision current integrators. The rare isotope ¹⁴C+ continues through a 90° electrostatic spherical analyzer (ESA) which removes any outstanding interferences and the beam is measured in a compact gas particle detector. NEC AMS systems include full computer control with AMS analysis software to provide chronological ages, carbon content in dpm/gm, or pMC (percent modern carbon) values.

For improved backgrounds of beryllium, the NEC XCAMS includes an energy depletion foil to remove boron, and an additional 45° magnet following the high energy ESA. For improved backgrounds of beryllium and aluminum, the NEC UAMS includes an energy depletion foil to remove boron, and an additional 45° magnet following the high energy ESA. NEC’s control system involves a save and restore feature to make switching between elements easy. 

NEC AMS systems can support several configurations from a single, 40 sample source, to dual 134 sample sources for a maximum throughput of 2,000 samples to 2% precision per week. Sample wheel loading takes less than 30 minutes with full 40 sample wheels typically measured to precision within about 24 hours. NEC ion sources have no noticeable memory effects and are extremely reliable. NEC has provided more than 125 MC-SNICS sources around the world.

The multiple isotope AMS systems proceed automatically to switch from sample to sample as the required precisions, time constraints, or other criteria are met. The system can be monitored remotely and is fully interlocked in case of power, water or air failure to protect personnel and precious samples.

Specifications

The Multiple Isotope AMS Systems provided by NEC are comparable on almost all measures. However, by moving to a UAMS, which is a 1 MV version of the XCAMS, users can measure calcium (Ca). Additional specifications are featured below.

AMS Ratios

XCAMS

UAMS

Related Documents