scholarly journals Status of the AMS graphitization system in the dendrochronological laboratory at AGH-UST, Kraków

2020 ◽  
Vol 47 (1) ◽  
pp. 112-117
Author(s):  
Damian Wiktorowski ◽  
Marek Krąpiec ◽  
Andrzej Rakowski ◽  
Alexander Cherkinsky
Keyword(s):  
Sample Preparation ◽  
Mass Spectrometer ◽  
Reproducibility Of Results ◽  
Good Reproducibility ◽  
Independent Components ◽  
The Third ◽  
Vacuum Line ◽  
Accelerator Mass Spectrometer ◽  
Pre Treatment ◽  
New System

AbstractA new system for the preparation of graphite samples for radiocarbon (14C) measurement using an accelerator mass spectrometer (AMS) has been built in the Dendrochronological Laboratory at AGH-UST, Kraków. This system consists of three independent components. The first is the equipment for mechanical and chemical sample pre-treatment. The second is the vacuum line for sample sealing and the purification of CO2. The third and central part of this system is a graphitization line, where graphite is produced from CO2. In the first stage, chemical sample preparation was carried out to remove impurities. IAEA and NIST OxII standard materials were converted to CO2 without pre-treatment. In the next step, samples were combusted to CO2. The resulting CO2 was released under vacuum and cryogenically purified for subsequent graphitization. The performance of the system was tested with NIST OxII, IAEA standards (IAEA C5, C6 and C7) and background samples. The test confirms good reproducibility of results obtained for the samples prepared using this system. The results of the 49 samples of NIST Ox-II, IAEA standards and blank samples were presented in this article.

scholarly journals 14C AMS at Suerc: Improving QA Data with the 5MV Tandem and 250KV SSAMS

Radiocarbon ◽  
2010 ◽  
Vol 52 (2) ◽  
pp. 263-271 ◽  
Author(s):  
P Naysmith ◽  
G T Cook ◽  
S P H T Freeman ◽  
E M Scott ◽  
R Anderson ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Sample Preparation ◽  
Mass Spectrometer ◽  
Random Access ◽  
Capacity Measurement ◽  
Tandem Accelerator ◽  
Standard Data ◽  
Accelerator Mass Spectrometer ◽  
On Line ◽  
Automated Data Acquisition

In 2003, a National Electrostatics Corporation (NEC) 5MV tandem accelerator mass spectrometer was installed at SUERC, providing the radiocarbon laboratory with 14C measurements to 4–5‰ repeatability. In 2007, a 250kV single-stage accelerator mass spectrometer (SSAMS) was added to provide additional 14C capability and is now the preferred system for 14C analysis. Changes to the technology and to our operations are evident in our copious quality assurance data: typically, we now use the 134-position MC-SNICS source, which is filled to capacity. Measurement of standards shows that spectrometer running without the complication of on-line δ13C evaluation is a good operational compromise. Currently, 3‰ 14C/13C measurements are routinely achieved for samples up to nearly 3 half-lives old by consistent sample preparation and an automated data acquisition algorithm with sample random access for measurement repeats. Background and known-age standard data are presented for the period 2003–2008 for the 5MV system and 2007–2008 for the SSAMS, to demonstrate the improvements in data quality.

A New Graphitization System for Radiocarbon Dating with AMS in the Dendrochronological Laboratory at AGH-UST Kraków

Radiocarbon ◽  
2018 ◽  
Vol 60 (4) ◽  
pp. 1091-1100 ◽  
Author(s):  
Marek Krąpiec ◽  
Andrzej Rakowski ◽  
Matthias Huels ◽  
Damian Wiktorowski ◽  
Christian Hamann
Keyword(s):  
Carbon Dioxide ◽  
Radiocarbon Dating ◽  
Age Determination ◽  
Younger Dryas ◽  
Vacuum System ◽  
Good Reproducibility ◽  
Chemical Preparation ◽  
Vacuum Line ◽  
Accelerator Mass Spectrometer ◽  
Subfossil Wood

AbstractA new vacuum system for the preparation of graphite samples for radiocarbon (14C) measurement using an accelerator mass spectrometer (AMS) was constructed at the Dendrochronological Laboratory in AGH-UST Kraków. The central part of the system is a manual vacuum line for the production of graphite from carbon dioxide for subsequent AMS measurements. The graphitization system can handle up to five samples simultaneously, and the process lasts for approximately 1 hour. The graphitization line was built to support the preparation of wood samples for a project dedicated to dating a subfossil tree from the Younger Dryas period. For this purpose, the chemical preparation procedure for wood samples was optimized to obtain more reliable results. This includes the extraction of α-cellulose to increase the precision of the age determination. The performance of the system was tested with NIST OxII, IAEA standards (IAEA C3, C5, C6, and C8), and background samples. The results of the 13 samples of subfossil wood were tested and are presented. The methodology gives good reproducibility of results obtained for the samples prepared using this system.

scholarly journals Operation experience of the BINP accelerator mass spectrometer

2018 ◽  
Author(s):  
S. Rastigeev ◽  
A. Frolov ◽  
A. Goncharov ◽  
V. Klyuev ◽  
E. Konstantinov ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Accelerator Mass Spectrometer

Accelerator mass spectrometer with ion selection in high-voltage terminal

2016 ◽  
Vol 13 (7) ◽  
pp. 923-926 ◽  
Author(s):  
S. A. Rastigeev ◽  
A. D. Goncharov ◽  
V. F. Klyuev ◽  
E. S. Konstantinov ◽  
L. A. Kutnyakova ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
High Voltage ◽  
Accelerator Mass Spectrometer

scholarly journals The New National Ocean Sciences Accelerator Mass Spectrometer Facility at Woods Hole Oceanographic Institution: Progress and First Results

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 478-482 ◽  
Author(s):  
K. F. Von Reden ◽  
G. A. Jones ◽  
R. J. Schneider ◽  
A. P. McNichol ◽  
G. J. Cohen ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Woods Hole Oceanographic Institution ◽  
Ocean Sciences ◽  
Start Up ◽  
Accelerator Mass Spectrometer ◽  
First Results ◽  
Injector Design

Start-up performance and first results of the new Woods Hole Accelerator Mass Spectrometer are discussed. Special attention is given to the hemispherical ionizer sputter source and the triple-isotope injector design.

Drei Verfahren zur Messung der Änderung der Austrittsarbeit mit Hilfe der Oberflächenionisation

1972 ◽  
Vol 27 (5) ◽  
pp. 794-803 ◽  
Author(s):  
R Müller ◽  
W Walcher ◽  
H.-W Wassmuth
Keyword(s):  
Work Function ◽  
Mass Spectrometer ◽  
Reference Electrode ◽  
Surface Ionization ◽  
Contact Potential ◽  
External Voltage ◽  
The Third ◽  
Metal Atoms ◽  
Ion Emission

AbstractThree methods for the measurement of the change ΔΦ of the work function Φ of a metal surface due to the presence of adsorbed particles (e. g. oxygen) have been developed utilizing the surface ionization of a beam of metal atoms (e. g. In, Sr) as a probe. The experiments have been performed with a mass spectrometer at ultrahigh vacuum.In the first method the temperature dependency of the ion emission current is used for the determination of the work function Φ considering certain limiting conditions. The two other methods which may be applied simultaneously with the first one, involve a direct measurement of ΔΦ by compensating the change of the contact potential by an external voltage: In the second method the contact potential between the ionizing surface and a surrounding reference electrode is used to control the ion optical conditions for the ion emission, whereas in the third method the change in the kinetic energy of the ions caused by a change of the contact potential between the ionizing surface and the entrance slit of the mass spectrometer is used as a measure of ΔΦ

scholarly journals Pegvisomant and Pasireotide LAR as second line therapy in acromegaly: clinical effectiveness and predictors of response

2021 ◽  
Vol 184 (2) ◽  
pp. 217-229
Author(s):  
Sabrina Chiloiro ◽  
Antonella Giampietro ◽  
Federica Mirra ◽  
Federico Donfrancesco ◽  
Tommaso Tartaglione ◽  
...  
Keyword(s):  
First Generation ◽  
Third Ventricle ◽  
Free Time ◽  
Second Line ◽  
Tumor Extension ◽  
The Third ◽  
Clinical Biomarkers ◽  
Predictors Of Response ◽  
Igf I ◽  
Pre Treatment

Background The treatment of acromegaly resistant to first-generation somatostatin receptor ligands (SRLs) is often difficult. Pegvisomant and Pasireotide LAR are mostly used in these subset of patients, as second line therapies. Choice of the type of second line therapies is difficult, since predictors of response are still unclear, impairing personalized therapy. We aimed to investigate predictors of response to Pegvisomant and Pasireotide LAR. Methods Seventy-four acromegaly patients entered this observational, cross-sectional and retrospective study if (i) resistant to high dose first-generation SRLs and (ii) treated with Pegvisomant and Pasireotide LAR for at least 12 consecutive months. Patients treated with radiotherapy in the previous 10 years were excluded. Results Fourty-one patients were treated with Pegvisomant and 33 with Pasireotide LAR. At the end of the study, acromegaly was controlled in 35 patients treated with Pegvisomant (85.4%) and in 23 treated with Pasireotide LAR (69.7%). In this cohort, a poor Pegvisomant response and a shorter progression free time were observed in cases with tumor extension to the third ventricle (P = 0.004, HR: 1.6, 95%CI: 1.2–4.6), with a Ki67-Li >4% (P = 0.004, HR: 3.49, 95%CI: 1.4–4.0) and with pre-treatment IGF-I >3.3×ULN (P=0.03, HR: 1.3, 95%CI: 1.1–6.0). A poor Pasireotide LAR response and a shorter progression free time were observed in cases with tumor extension to the third ventricle (P=0.025, HR: 1.6 95%CI: 1.4–3.4), pre-treatment IGF-I >2.3×ULN (P=0.049, HR: 2.4, 95%CI: 1.4–8.0), absent/low SST5 membranous expression (P=0.023 HR: 4.56 95%CI: 1.3–6.4) and in patients carried the d3-delated GHR isoform (P=0.005, HR: 11.37, 95%CI: 1.3–20.0). Conclusion Molecular and clinical biomarkers can be useful in predicting the responsiveness to Pegvisomant and Pasireotide LAR.

scholarly journals Pan-STARRS, ATLAS and optical transient searches

2013 ◽  
Vol 371 (1992) ◽  
pp. 20120269 ◽  
Author(s):  
J. L. Tonry
Keyword(s):  
Alert System ◽  
Transient Detection ◽  
The Third ◽  
Search Area ◽  
Deep Fields ◽  
Optical Transient ◽  
New System

The Pan-STARRS1 survey is collecting multi-epoch, multi-colour observations of the sky north of declination −30 ° , and has designated 70 deg 2 for nightly observations that are particularly useful for transient detection. A duplicate, Pan-STARRS2, is nearing completion that offers opportunities to improve the quality of transient search and observation, as well as simply increasing the number of detections. A new system, the Asteroid Terrestrial-impact Last Alert System (ATLAS), increases the search area to all-sky in return for diminished sensitivity, and highlights tension among optimization for static sky images, optimization for faint transients and optimization for an unbiased number of transients. ATLAS gives up sub-arcsecond images and full colour information to specialize in the third category, but should detect many more transients than the Pan-STARRS1 Medium Deep fields or the Palomar Transient Factory, with examples of transient classes that are considerably closer and brighter.

scholarly journals A High Throughput 14C Accelerator Mass Spectrometer

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 458-467 ◽  
Author(s):  
Kenneth H. Purser
Keyword(s):  
Mass Spectrometer ◽  
Unique Feature ◽  
Isotopic Ratios ◽  
Tandem Accelerator ◽  
Ocean Sciences ◽  
Accelerator Mass Spectrometer ◽  
Recent Sample ◽  
Present Design ◽  
On Line ◽  
Differential Transmission

I present design details of a tandem accelerator mass spectrometer, which has been installed at the National Ocean Sciences AMS Facility at Woods Hole, Massachusetts, to provide precision 14C/13C/12C isotopic ratios for sub-milligram-size samples of graphite with throughputs of >4000 samples per year. A unique feature is the capability for simultaneous measurement of all three isotopes after acceleration, to avoid differential transmission effects and to allow on-line fractionation corrections and diagnosis of instrument health. Using filamentous graphite fabricated from a recent sample, we have established the counting rate of 14C ions at between 60–120 s–1.

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