- EnvironMICADAS AMS and sample preparation laboratory for C-14 analyses
- Gas proportional counting system (GPC)
- VG-5400 noble gas mass spectrometer
- Thermo Finnigan Deltaplus XP isotope ratio mass spectrometer (IRMS)
- Low-backround gamma- and beta-spectrometry laboratory
- Inductively coupled plasma mass spectrometry (LA-ICP-MS)
- Neptun Plus high resolution multi collector ICP-MS
- A MAT 253 Plus clumped isotope mass spectrometer
EnvironMICADAS AMS and sample preparation laboratory for C-14 analyses
C-14 dating and Environmental Research
Gas Ion Source Interface
Background: 50.000 yrs BP
Quality Managemenet System ISO 9001: 2008
The EnvironMICADAS AMS was installed in Atomki during the summer of 2011. The system is also specialized for environmental studies besides C-14 dating. The detection limit is 50,000 yrs BP.
The specialized Gas Ion Source Interface was developed in collaboration with the Laboratory of Ion Physics at ETH (Zürich). It is used for the routine C-14 analyses of very small samples (< 50 ug C) at high throughput and low measurement uncertainties in an automated system.
Gas proportional counting system (GPC)
The gas proportional counting system was developed for high precision radiocarbon dating and consists of nine electrolytic copper proportional counters of identical diameters with sensitive volumes of 0.35-0.73 dm3 and filled with CO2 at 1115 mbar and 2 bar.
The counter system is located in a lead shield (1250 mm x 950 mm x 800 mm) with a wall thickness of 100 mm and 200 mm on the top. A 200 mm boron loaded paraffin layer is used inside the lead shield for thermalization and absorption of neutrons produced by cosmic ray particles in the lead.
The inner counters are surrounded by an anticoincidence shield consisting of five multiwire proportional flat counters filled with propane up to 1 bar. The pulses of the detectors are handled by integrated amplifiers, discriminators and anticoincidence units interfaced to a microprocessor-controlled data evaluation unit.
The overall precision of the system for modern carbon samples is better than 4‰ after a counting period of seven days.
VG-5400 noble gas mass spectrometer
The VG-5400 is a dedicated mass spectrometer for noble gas isotopes. It is a double focusing instrument with extended geometry.
It has a Nier-type ion source, an electromagnetic analyser, a Faraday collector with a 100 GOhm resistor, and an ion counter (SEM: secondary electron multiplier). The sample is admitted the mass spectrometer through a cryogenic preparation and purification line. The sensitivity of the mass spectrometer is 1×10-3 A/Torr and 2×10-4 A/ Torr for argon and helium, respectively. It enables us to detect even 5000 3He atoms. The resolution of more than 600 at 3 amu allows us to resolve a 3He+ peak and H3+/HD+ double peak.
The tritium concentration of environmental water samples are determined via the mass spectrometric analysis of its daughter, 3He. The pressure sensitivity and hence the systematic error of the measurement of low level helium abundances are eliminated by adding an ultrapure 4He spike to each tritiogenic 3He samples. The 10-20 % of systematic error could be reduced below 2 permil. Besides tritium analyses, noble gases dissolved in groundwater are determined by the mass spectrometer. 3H/3He apparent ages and recharge temperatures can be calculated from the noble gas concentrations and helium isotope ratios. All these values are applied in the research of recharge areas and palaeoclimate.
Thermo Finnigan Deltaplus XP isotope ratio mass spectrometer (IRMS)
The laboratory has a Thermo Finnigan Deltaplus XP isotope ratio mass spectrometer (IRMS), which is specially designed for measurement of light environmental stable isotopes 2H, 13C, 15N, 18O, 34S is a sensitive and selective instrument with application in hydrology, geology, environmental protection, paleoclimate.
Prior to stable isotope ratio measurements different samples has to be brought in gaseous form. A host of preparation methods have been developed and improved to convert different sample compounds to an appropriate gas including H2, CO, CO2, N2, and SO2. The measured values expressed in delta notation like δ2H, δ13C, δ15N, δ18O, δ34S The delta values are defined as follows: δ (‰) = (Rsample/ Rreference-1) * 1000, where R is the 13C/12C, 15N/14N or 34S/32S etc. ratio in the sample or in the international reference.
The isotope results were calculated on the basis of the known values of international standard materials.
The Elemental Analyser (Fisons NA1500 NCS) is based on the complete and instantaneous oxidation of the sample by flash combustion which converts all organic and inorganic substances into combustion products. The resulting combustion gases pass through a reduction furnace and are swept into the chromatographic column by the carrier gas (helium). The gases are separated in the column and detected by the IRMS (δ13C, δ15N, δ34S). Isotopic analyses of water samples or carbonates are carried out with an automated GASBENCH II sample preparation device attached to the IRMS. Hydrogen and oxygen isotopes of the water, carbon and oxygen isotopes of carbonate samples are measured by this method. The high temperature conversion elemental analyser (TC/EA) coupled to the IRMS is suitable to determine the δ2H and δ18O values of solid samples and of fluid samples as well.
Low-background gamma- and beta-spectrometry laboratory
This laboratory consists of two ultralow-background liquid scintillation counters (LSCs) and two ultralow-background gamma spectrometers, all of which are among the best of their kinds. The laboratory has been designed and configured for low-level and low-background activity measurements. The equipment in this facility can be used for the detection of gamma-emitters as well as pure-beta isotopes such as 3H, 14C, 36Cl, 90Sr, 99Tc with low detection limits. One of the possible applications is the tracing of the residue of the nuclear weapon tests and that of the Chernobyl NPP accident in sediment sequences.
The HPGe detector of the Canberra-Packard made BE5030-7915-30ULB thin-windowed, broad-energy gamma-spectrometer is situated in high-purity lead shielding. For sediment samples of about 10 g (dispersed in a thin layer), the detection efficiency of the natural fallout 210Pb is about 18%, while the Compton background in this region is around 0.3 cpm. This enables the quantification of 2-3 Bq/kg excess 210Pb, compared to the 226Ra baseline. From the same measurement the MDA for the anthropogenic (e.g. nuclear weapon tests and Chernobyl NPP accident) fallout 241Am-re and 137Cs is around 1-2 Bq/kg, in case of 36 hours counting time.
The Tri-Carb 3180 TR/SL is a computer-controlled benchtop liquid scintillation counter by Perkin-Elmer for detecting small amounts of beta radioactivity with multi-parameter linear MCA. Special proprietary “Surround TR-LSC” BGO (Bismuth Germanium Oxide) detector guard surrounds the sample in the counting chamber, enhances discrimination against background and yields the highest E2/B values available in a multipurpose liquid scintillation counting system. It is specially designed for counting extremely low activity samples in disposable glass and plastic vials. Background for 3H and 14C is 1,0 – 0,75 cpm and 0,3 cpm, respectively.
Super low level counting is available for extremely low activity beta samples, increasing system sensitivity (E2/B) to a factory test minimum of 880 for 3H and 6,000 for 14C. The detection limit for 3H without enrichment is ≤ 1 Bq/l, in case of 500 minutes counting time.
Inductively coupled plasma mass spectrometry (LA-ICP-MS)
Inductively coupled plasma mass spectrometry has been accessible since 2013 in our laboratory (Agilent 8800 ICP-MS triplequad). The method is useful for the determination almost all of the chemical elements and isotopes (exept hydrogen, noble gases and fluorine) in ngL-1 – mgL-1 concentration range.
Placing a collision/reaction cell between two quadrupol unit was an effective design to eliminate interferences. Beside of the low level measurements, isotope ratio determinations are although available. (e.g. concentrations of Ag, As, I, Th, and U in surface and ground waters are rutine based measured with this method).
Direct analysis of solid samples is available using laser ablation coupled with ICP-MS. Concentration and isotope ratio mapping, Th/U dating of zircon christals, measurement of rare earth (REE) elements in environmental samples, and analyis of platinum group elements are the major topics for this technique.
Neptune Plus high resolution multi collector ICP-MS
- A new multicollector ICP-MS will be installed in early 2018.
MAT 253 Plus clumped isotope mass spectrometer
- A new MAT 253 Plus and a Kiel IV automatic carbonate device will be installed in December 2017.