ION SELECTION IN ACCELERATOR MASS SPECTROMETER BINP SB RAS. V. V. Parkhomchuk, S.A. Rastigeev BINP, Novosibirsk, Russia. The BINP AMS is mainly dedicated for dating of archaeological and geological samples by measurements of the ratio between carbon isotopes.
ION SELECTION IN ACCELERATOR MASS SPECTROMETER BINP SB RAS
V. V. Parkhomchuk, S.A. Rastigeev BINP, Novosibirsk, Russia.
The BINP AMS is mainly dedicated for dating of archaeological and geological samples
of the ratio between carbon isotopes.
AMS can be used for many others applications.
For modern carbon
The amount of 14C for dead samples
decreases through decay with a half-life of 5730 years.
(About 108molecular isobars
for each negative radiocarbon ion in modern samples)
Mass spectrum of the modern sample archaeological and geological samples
low energy spectrum
11orders of magnitude
at the exit of
Electrostatic filter archaeological and geological samples
The scattering and charge exchange processes
allow the unwanted particles to pass through electrostatic
and magnetic filters. The ions can interact with molecules
of residual gas and parts of vacuum chamber.
AMS method archaeological and geological samples
is based on the direct rare isotope counting
1 - pressure tank,
2 - accelerator tube,
3 - cascade generator,
4 - middle energy
5 - magnesium vapors stripper,
6 - ion source,
7 - low-energy magnetic analyzer,
8- high-energy magnetic analyzer
recharging in accelerator tubes archaeological and geological samples
a) 16O background, b) 16O
a) 13C background, b) 12C background
14 archaeological and geological samples N background
Without tandem terminal filter:
With tandem terminal filter:
The 14N and 14C ions energy have the same values at the exit of accelerator only after five steps recharging process.
Moreover, the magnesium vapors stripper had no the
observable influence on vacuum condition
2D TOF spectrum archaeological and geological samples
“dead” sample(graphite MPG) 14C/12C~2*10-15