Isotopic metrology of carbon dioxide. II. Effects of ion source materials, conductance, emission, and accelerating voltage on dual-inlet cross contamination

2003 ◽  
Vol 17 (8) ◽  
pp. 777-782 ◽  
Author(s):  
R. Michael Verkouteren ◽  
Sergey Assonov ◽  
Donna B. Klinedinst ◽  
Willi A. Brand
Keyword(s):  
Carbon Dioxide ◽  
Ion Source ◽  
Cross Contamination ◽  
Source Materials

Quantum state control on the chemical reactivity of a transition metal vanadium cation in carbon dioxide activation

2019 ◽  
Vol 21 (13) ◽  
pp. 6868-6877 ◽  
Author(s):  
Yih Chung Chang ◽  
Yuntao Xu ◽  
Cheuk-Yiu Ng
Keyword(s):  
Carbon Dioxide ◽  
Transition Metal ◽  
Electronic State ◽  
Quantum State ◽  
Electron Spin ◽  
Chemical Reactivity ◽  
Ion Source ◽  
Atomic Transition ◽  
Spin Orbit ◽  
State Control

By utilizing a newly developed spin-orbit electronic state selected ion source for atomic transition metal vanadium cation (V+), the chemical reactivity of V+ with CO2 has been examined in detail, indicating that the titled reaction is dominantly governed by electron spin conservation, and thus the chemical reactivity can be controlled by quantum electronic state selections.

scholarly journals Using a Gas Ion Source for Radiocarbon AMS and GC-AMS

Radiocarbon ◽  
2004 ◽  
Vol 46 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Christopher Bronk Ramsey ◽  
Peter Ditchfield ◽  
Martin Humm
Keyword(s):  
Mass Spectrometry ◽  
Carbon Dioxide ◽  
Gas Chromatography ◽  
Continuous Flow ◽  
Direct Injection ◽  
Ion Source ◽  
Handling System ◽  
Peak Separation ◽  
Similar Work ◽  
High Voltage Engineering

This paper reports on the performance of a new method of sample injection using the High Voltage Engineering Europa (HVEE) SO-110 ion source jointly developed between HVEE and Oxford. In order to use this source, we have developed a new gas handling system which works on the direct injection of carbon dioxide mixed into a continuous flow of helium. Preliminary work has also been carried out on online gas chromatography-accelerator mass spectrometry (GC-AMS). In this application, a GC is directly coupled to the AMS system using a GC-IRMS combustion interface and Nafion™ drier. We show here results for the measurement of natural abundance in separated compounds with good peak separation and precisions of about 10%. This type of system should be ideal for source apportionment studies, biomedical, and other similar work where high precision is not required but where sample sizes are very low.

scholarly journals Sample Chemistry for the Oxford High Energy Mass Spectrometer

Radiocarbon ◽  
1983 ◽  
Vol 25 (2) ◽  
pp. 771-774 ◽  
Author(s):  
Richard Gillespie ◽  
Robert E M Hedges
Keyword(s):  
Mass Spectrometer ◽  
Sample Pretreatment ◽  
Chemical Compounds ◽  
High Energy ◽  
Ion Source ◽  
Small Samples ◽  
Specific Chemical ◽  
Geologic Samples ◽  
Source Materials ◽  
Accelerator System

Chemical pretreatment procedures for the decontamination, extraction, and isolation of organic materials for 14C dating using the Oxford accelerator system are described. Specific details are given for the isolation and chromatographic purification of amino acids from bone and tooth collagen, of lipids from sediments, and of cellulose and glucose from wood, paper, and textiles. A description is also given of the apparatus used for the routine preparation of 1 to 5mg graphite samples on tantalum wire, for use in the accelerator ion source.The high energy mass spectrometer (HEMS) approach to 14C dating allows the use of very small samples in the low milligram range. Sample pretreatment and decontamination procedures can be both more vigorous and more selective than those used by conventional dating laboratories. Specific chemical compounds can be isolated from archaeologic or geologic samples; such compounds may be characteristic of particular source materials and, hence, provide more detailed information than is generally possible using bulk organic samples. The Oxford Radiocarbon Unit has concentrated on three sample types that represent the kind of material we expect to work on initially: bone, lake sediment, and wood.

The effects of intracage ventilation on micro environmental conditions in filter-top cages

1992 ◽  
Vol 26 (3) ◽  
pp. 206-210 ◽  
Author(s):  
Neil S. Lipman ◽  
Brian F. Corning ◽  
Michael A. Coiro
Keyword(s):  
Carbon Dioxide ◽  
Relative Humidity ◽  
Environmental Conditions ◽  
Particulate Material ◽  
Prototype System ◽  
Cross Contamination ◽  
Carbon Dioxide Levels

Filter-top cages, while effective in reducing cross contamination by particulate material including microbes, can also cause accumulation of the waste gases carbon dioxide and ammonia as well as increased intracage relative humidity. A prototype system which provided each cage with 23 air changes per hour through a nozzle inserted in the filter lid was evaluated. The ventilated cageing system was effective in reducing intracage carbon dioxide, ammonia and relative humidity levels. Mean weekly carbon dioxide levels were 2900 ppm lower, ammonia levels 240 ppm lower and intracage relative humidity levels 8% lower in the ventilated cages than in unventilated controls.

scholarly journals PLASMA ASSISTED CONVERSION OF CARBON DIOXIDE IN LOW-PRESSURE GAS DISCHARGES

2019 ◽  
pp. 141-146
Author(s):  
S.V. Dudin ◽  
A.V. Zykov ◽  
S.D. Yakovin
Keyword(s):  
Carbon Dioxide ◽  
Inductively Coupled Plasma ◽  
Plasma Source ◽  
Low Pressure ◽  
Ion Source ◽  
Anode Layer ◽  
Magnetron Discharge ◽  
Gas Discharges ◽  
Inductively Coupled ◽  
High Conversion Rate

Experimental results of comparative study of carbon dioxide conversion efficiency to CO and O2 in the plasmas of different low-pressure discharges are presented. Inductively coupled plasma source, magnetron discharge and anode layer discharge in Hall-type ion source were used in CO2 pressure range 0.5…3 mTorr. It is shown that the best combination of high conversion rate with significant energy efficiency of the conversion is demonstrated by the ICP source.

scholarly journals On-line Radiocarbon Measurements of Small Samples Using Elemental Analyzer and MICADAS Gas Ion Source

Radiocarbon ◽  
2010 ◽  
Vol 52 (4) ◽  
pp. 1645-1656 ◽  
Author(s):  
M Ruff ◽  
S Fahrni ◽  
H W Gäggeler ◽  
I Hajdas ◽  
M Suter ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Combustion Products ◽  
Ion Source ◽  
Small Samples ◽  
Inlet System ◽  
Line System ◽  
Line Measurement ◽  
On Line ◽  
Cryogenic Trapping ◽  
Gas Tight

An on-line measurement system was installed at the MICADAS in Zurich, using an elemental analyzer (EA) as a combustion unit to enable direct radiocarbon measurement of samples containing carbon in the range of 5–100 μg possible with minimum effort. The samples are combusted in small capsules and the gaseous combustion products are separated by the EA. The carbon dioxide leaving the EA in a high helium flow is concentrated on a small external trap containing X13 zeolite adsorber material. This new concept, avoiding a cryogenic trapping for the enrichment step, allows the construction of a very compact system able to work even with the smallest samples. Concentrated on the external trap, the carbon dioxide is flushed into the gas-tight syringe of our gas inlet system using a low helium stream. The gas mixture is measured with the MICADAS gas ion source. Several different sample capsules were analyzed to minimize the major blank contribution coming from the sample vessel. The best results were achieved with 25-μL tin capsules, which contained only 0.34 ± 0.13 μg carbon at 65 pMC. This work describes the development of the on-line system and the protocol for measurement runs. Results are presented for on-line measurements of reference materials and a comparison is performed with typical dating samples measured previously as graphite targets. Finally, relevance and limitations of on-line measurements are discussed.

Elimination DNA database – an opportunity or a threat? A review of the functioning of elimination databases in selected countries

2017 ◽  
Vol 295 ◽  
pp. 43-55
Author(s):  
Katarzyna Ćwik ◽  
Keyword(s):  
Present System ◽  
Cross Contamination ◽  
Legal Basis ◽  
European Network ◽  
Dna Databases ◽  
Database Querying ◽  
Dna Database ◽  
The Subject ◽  
Contamination Events ◽  
Source Materials

One of the basic provisions laying down the rationale for the functioning of elimination DNA databases is the 20th recommendation of the European Network of Forensic Science Institutes - ENFSI, set out in the document entitled: “The DNA Database management. Review and recommendations”, developed by ENFSI DNA Working Group. The recommendation states clearly that each DNA database should also include an elimination database(s) containing the profiles and data of persons who may have been the source of the so-called cross-contamination of traces being the subject of analysis. The purpose of this article was to illustrate the essence of functioning of elimination DNA databases on the example of selected countries, with particular regard to, among others, system solutions applied, directories of persons subject to registration, legal basis and the number of contamination events detected as a result of database querying. A bibliographic query and analysis of source materials and foreign procedures enabled the author to present system solutions and the basics of functioning of selected elimination DNA databases established worldwide. Moreover, the author emphasized the importance of elimination databases as a tool for identifying the offenders and highlighted certain opportunities and risks involved in their implementation.

scholarly journals Memory Effects in an AMS System: Catastrophe and Recovery

Radiocarbon ◽  
1990 ◽  
Vol 32 (1) ◽  
pp. 81-83 ◽  
Author(s):  
J S Vogel ◽  
J R Southon ◽  
D E Nelson
Keyword(s):  
Sample Preparation ◽  
Ion Source ◽  
Reaction Vessel ◽  
Memory Effects ◽  
Cross Contamination ◽  
Contamination Factors ◽  
Cleaning Procedures

A sample with a 14C concentration estimated to be greater than 30,000 Modern was inadvertently graphitized and measured in an AMS system. No measurable contamination of the cesium sputter ion source was observed. Simple cleaning procedures removed the contamination from the sample preparation system, with the exception of the reaction vessel in which the sample was graphitized. Sample cross-contamination factors were estimated for all of the preparation and measurement procedures.

Experimental investigation of carbon dioxide cross-contamination in sorption energy recovery wheel in ventilation system

2017 ◽  
Vol 39 (4) ◽  
pp. 463-474 ◽  
Author(s):  
Miklos Kassai
Keyword(s):  
Carbon Dioxide ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Energy Recovery ◽  
Ventilation System ◽  
Test Facility ◽  
High Humidity ◽  
Cross Contamination ◽  
Heat And Moisture

The aim of this research was to investigate the scale of carbon dioxide recirculation in rotary energy wheel operated in air handling units. To achieve this objective, a test facility was installed into the indoor air quality and thermal comfort laboratory of BUTE University. A newly developed molecular 3 Å sieve sorption wheel with high humidity transfer efficiencies is integrated into the experimental setup. In this research study, carbon dioxide cross-contamination rate from the exhaust side into the supply side in sorption regenerative air-to-air rotary energy exchanger was conducted by experimental tests. During the study, the correlation between the carbon dioxide cross-contamination, different rotational speeds of the wheel and different volume flow rates of supply air were also investigated in detail. Based on the results, a rotation speed diagram – carbon dioxide cross-contamination diagram – is plotted which can be very useful for researchers, developers and building service engineers in practice. Practical application: The most perfect energy exchanger can transfer both heat and moisture, thus providing a pleasant indoor air quality in the conditioned space. It is beneficial if the exchanger can transfer heat and moisture between the supply and exhaust airstreams, thereby minimizing the capacity and energy consumption of the required auxiliary heater and humidifier. The auxiliary energy reduction can be especially high if the sorption material of the energy wheel is of type 3 Å molecular sieve that has an extremely high humidity transfer capacity. The disadvantage of the rotary energy recovery is the cross-contamination from the exhaust air to the supply air. This is very important because in places such as offices, schools, public institutions, carbon dioxide cross-contamination can cause degradation of indoor air quality.

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