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.

scholarly journals High-Level 14C Contamination and Recovery at Xi'an AMS Center

Radiocarbon ◽  
2012 ◽  
Vol 54 (02) ◽  
pp. 187-193
Author(s):  
Weijian Zhou ◽  
Shugang Wu ◽  
Todd E Lange ◽  
Xuefeng Lu ◽  
Peng Cheng ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Ion Source ◽  
Cleaning Procedures ◽  
Contamination Event ◽  
High Level

A sample with a radiocarbon concentration estimated to be greater than 105times Modern was inadvertently graphitized and measured in the Xi'an AMS system last year. Both the sample preparation lines and the ion source system were seriously contaminated and a series of cleaning procedures were carried out to remove the contamination from them. After repeated and careful cleaning as well as continuous flushing with dead CO2gas, both systems have recovered from the contamination event. The machine background is back to 2.0 x 10–16and the chemical blank is beyond 50 kyr.

scholarly journals High-Level 14C Contamination and Recovery at Xi'an AMS Center

Radiocarbon ◽  
2012 ◽  
Vol 54 (2) ◽  
pp. 187-193 ◽  
Author(s):  
Weijian Zhou ◽  
Shugang Wu ◽  
Todd E Lange ◽  
Xuefeng Lu ◽  
Peng Cheng ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Ion Source ◽  
Cleaning Procedures ◽  
Contamination Event ◽  
High Level

A sample with a radiocarbon concentration estimated to be greater than 105 times Modern was inadvertently graphitized and measured in the Xi'an AMS system last year. Both the sample preparation lines and the ion source system were seriously contaminated and a series of cleaning procedures were carried out to remove the contamination from them. After repeated and careful cleaning as well as continuous flushing with dead CO2 gas, both systems have recovered from the contamination event. The machine background is back to 2.0 x 10–16 and the chemical blank is beyond 50 kyr.

scholarly journals Improvements and Applications of AMS Radiocarbon Measurement at Peking University

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 705-710 ◽  
Author(s):  
Zhiyu Guo ◽  
Kexin Liu ◽  
Kun Li ◽  
Jianjun Wang ◽  
Bin Li ◽  
...  
Keyword(s):  
Sample Preparation ◽  
High Intensity ◽  
Ion Source ◽  
System Stability ◽  
Preparation Technique ◽  
Graphite Sample ◽  
Sample Preparation Technique ◽  
Peking University

AMS radiocarbon measurements were started at Peking University in 1992 with a modified HICONEX 834 ion source. Some archaeological samples were measured at a sensitivity of 10−14 with ca. 1.7% precision for modern samples. We have made many improvements in our first two years of operation: a high-intensity Cs sputtering ion source was installed; the graphite sample preparation technique was investigated; and the system stability has been improved. The blank sample background is currently ca. 0.006 MC and a precision within 1% can be reached for modern samples. Geological, archaeological, environmental and biomedical samples can be measured routinely. We present some typical applications.

scholarly journals Transfer of Salmonella Enteritidis to four types of surfaces after cleaning procedures and cross-contamination to tomatoes

2012 ◽  
Vol 30 (2) ◽  
pp. 453-456 ◽  
Author(s):  
Vanessa Mendonça Soares ◽  
Juliano Gonçalves Pereira ◽  
Cibeli Viana ◽  
Thiago Braga Izidoro ◽  
Luciano dos Santos Bersot ◽  
...  
Keyword(s):  
Salmonella Enteritidis ◽  
Cross Contamination ◽  
Cleaning Procedures

scholarly journals 14C Analysis and Sample Preparation at the New Bern Laboratory for the Analysis of Radiocarbon with AMS (LARA)

Radiocarbon ◽  
2014 ◽  
Vol 56 (02) ◽  
pp. 561-566 ◽  
Author(s):  
Sönke Szidat ◽  
Gary A Salazar ◽  
Edith Vogel ◽  
Michael Battaglia ◽  
Lukas Wacker ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Ion Source ◽  
Carbon Dating ◽  
Climate Research ◽  
Accelerator Mass Spectrometer ◽  
History Of ◽  
Set Up ◽  
University Of Bern ◽  
The University

The University of Bern has set up the new Laboratory for the Analysis of Radiocarbon with AMS (LARA) equipped with an accelerator mass spectrometer (AMS) MICADAS (MIni CArbon Dating System) to continue its long history of14C analysis based on conventional counting. The new laboratory is designated to provide routine14C dating for archaeology, climate research, and other disciplines at the University of Bern and to develop new analytical systems coupled to the gas ion source for14C analysis of specific compounds or compound classes with specific physical properties. Measurements of reference standards and wood samples dated by dendrochronology demonstrate the quality of the14C analyses performed at the new laboratory.

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