A P McNichol
Datos Biográficos
| ID | 5597402 |
|---|---|
| NOMBRE | A P McNichol |
| NOMBRES | A P |
| APELLIDO | McNichol |
| FIRMA | MCNICHOL A P |
| VERIFICADO | No |
| TOTAL DE OBRAS | 10 |
| TOTAL DE CITAS | 99 |
| TOTAL COMO AUTOR | 10 |
| TOTAL COMO EDITOR | 0 |
| PRIMER AÑO DE PUBLICACIÓN | 1992 |
| AÑO MÁS RECIENTE DE PUBLICACIÓN | 2013 |
| ÍNDICE H | 6 |
Intercomparison of 14 C Analysis of Carbonaceous Aerosols
Radiocarbon analysis of the carbonaceous aerosol allows an apportionment of fossil and non-fossil sources of airborne particulate matter (PM). A chemical separation of total carbon (TC) into its subtractions organic carbon (OC) and elemental carbon (EC) refines this powerful technique, as OC and EC originate from different sources and undergo different processes in the atmosphere. Although 14 C analysis of TC, EC, and OC has recently gained incre…
A High-Performance 14 C Accelerator Mass Spectrometry System
A new and unique radiocarbon accelerator mass spectrometry (AMS) facility has been constructed at the Woods Hole Oceanographic Institution. The defining characteristic of the new system is its large-gap optical elements that provide a larger-than-standard beam acceptance. Such a system is ideally suited for high-throughput, high-precision measurements of 14 C. Details and performance of the new system are presented
Woce Radiocarbon IV
The World Ocean Circulation Experiment, carried out between 1990 and 1997, provided the most comprehensive oceanic survey of radiocarbon to date. Approximately 10,000 samples were collected in the Pacific Ocean by U.S. investigators for both conventional large volume p counting and small volume accelerator mass spectrometry analysis techniques. Results from six cruises are presented. The data quality is as good or better than previous large-scale…
Converting AMS Data to Radiocarbon Values
We summarize the basic operation of accelerator mass spectrometry (AMS) systems used to measure radiocarbon and discuss the calculations used to convert AMS output to 14 C data
The Radiocarbon Content of Individual Lignin-Derived Phenols
We present a method for the isolation of phenolic compounds derived from lignin for radiocarbon analysis. These phenols are generated by chemical oxidation of polymeric materials and derivatized for separation and recovery by preparative capillary gas chromatography (PCGC). This technique yields tens of micrograms of pure, stable compounds that can be converted to graphite and analyzed by accelerator mass spectrometry (AMS). Analysis of model fla…
Woce AMS Radiocarbon I
AMS radiocarbon results from the World Ocean Circulation Experiment in the Pacific Ocean show dramatic changes in the inventory and distribution of bomb-produced 14 C since the time of the GEOSECS survey (8/73–6/74). Near-surface Δ 14 C values for the eastern portion of both the northern and southern subtropical gyres decreased by 25–50‰, with the change being greater in the north. Equatorial near-surface values have increased by ca. 25‰. Changes…
Improvements in Procedural Blanks at Nosams
During the four years the Sample Preparation Laboratory (SPL) at the National Ocean Sciences Accelerator Mass Spectrometer (NOSAMS) Facilty has been in operation we have accumulated much data from which we can assess our progress. We evaluate our procedural blanks here and describe modifications in our procedures that have improved our analyses of older samples. In the SPL, we convert three distinct types of samples—seawater, CaCO 3 and organic c…
Measurements of the Oxalic Acid II/Oxalic Acid I Ratio as a Quality Control Parameter at Nosams
Precision of AMS single-target measurements is usually based on counting statistics and variance during the data acquisition cycle. Additional longer-term variability may be studied by looking at the variability of the standards from cycle to cycle
The Rapid Preparation of Seawater ΣCO 2 for Radiocarbon Analysis at the National Ocean Sciences Ams Facility
We have established a laboratory for extracting ΣCO 2 from seawater samples for AMS analysis of the radiocarbon content. The seawater samples are collected at sea, poisoned and stored until analysis in the laboratory. Each sample is acidified; the inorganic carbon is stripped out as CO 2 with an inert carrier gas and then converted to graphite. We present results for Buzzards Bay surface H 2 O and Na 2 CO 3 standards that demonstrate we strip >98…
The New National Ocean Sciences Accelerator Mass Spectrometer Facility at Woods Hole Oceanographic Institution
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
The Rapid Preparation of Seawater ΣCO 2 for Radiocarbon Analysis at the National Ocean Sciences Ams Facility
We have established a laboratory for extracting ΣCO 2 from seawater samples for AMS analysis of the radiocarbon content. The seawater samples are collected at sea, poisoned and stored until analysis in the laboratory. Each sample is acidified; the inorganic carbon is stripped out as CO 2 with an inert carrier gas and then converted to graphite. We present results for Buzzards Bay surface H 2 O and Na 2 CO 3 standards that demonstrate we strip >98…
Woce AMS Radiocarbon I
AMS radiocarbon results from the World Ocean Circulation Experiment in the Pacific Ocean show dramatic changes in the inventory and distribution of bomb-produced 14 C since the time of the GEOSECS survey (8/73–6/74). Near-surface Δ 14 C values for the eastern portion of both the northern and southern subtropical gyres decreased by 25–50‰, with the change being greater in the north. Equatorial near-surface values have increased by ca. 25‰. Changes…
Woce Radiocarbon IV
The World Ocean Circulation Experiment, carried out between 1990 and 1997, provided the most comprehensive oceanic survey of radiocarbon to date. Approximately 10,000 samples were collected in the Pacific Ocean by U.S. investigators for both conventional large volume p counting and small volume accelerator mass spectrometry analysis techniques. Results from six cruises are presented. The data quality is as good or better than previous large-scale…
A High-Performance 14 C Accelerator Mass Spectrometry System
A new and unique radiocarbon accelerator mass spectrometry (AMS) facility has been constructed at the Woods Hole Oceanographic Institution. The defining characteristic of the new system is its large-gap optical elements that provide a larger-than-standard beam acceptance. Such a system is ideally suited for high-throughput, high-precision measurements of 14 C. Details and performance of the new system are presented
Measurements of the Oxalic Acid II/Oxalic Acid I Ratio as a Quality Control Parameter at Nosams
Precision of AMS single-target measurements is usually based on counting statistics and variance during the data acquisition cycle. Additional longer-term variability may be studied by looking at the variability of the standards from cycle to cycle
Converting AMS Data to Radiocarbon Values
We summarize the basic operation of accelerator mass spectrometry (AMS) systems used to measure radiocarbon and discuss the calculations used to convert AMS output to 14 C data
Intercomparison of 14 C Analysis of Carbonaceous Aerosols
Radiocarbon analysis of the carbonaceous aerosol allows an apportionment of fossil and non-fossil sources of airborne particulate matter (PM). A chemical separation of total carbon (TC) into its subtractions organic carbon (OC) and elemental carbon (EC) refines this powerful technique, as OC and EC originate from different sources and undergo different processes in the atmosphere. Although 14 C analysis of TC, EC, and OC has recently gained incre…
Improvements in Procedural Blanks at Nosams
During the four years the Sample Preparation Laboratory (SPL) at the National Ocean Sciences Accelerator Mass Spectrometer (NOSAMS) Facilty has been in operation we have accumulated much data from which we can assess our progress. We evaluate our procedural blanks here and describe modifications in our procedures that have improved our analyses of older samples. In the SPL, we convert three distinct types of samples—seawater, CaCO 3 and organic c…
The New National Ocean Sciences Accelerator Mass Spectrometer Facility at Woods Hole Oceanographic Institution
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
The Radiocarbon Content of Individual Lignin-Derived Phenols
We present a method for the isolation of phenolic compounds derived from lignin for radiocarbon analysis. These phenols are generated by chemical oxidation of polymeric materials and derivatized for separation and recovery by preparative capillary gas chromatography (PCGC). This technique yields tens of micrograms of pure, stable compounds that can be converted to graphite and analyzed by accelerator mass spectrometry (AMS). Analysis of model fla…
The New National Ocean Sciences Accelerator Mass Spectrometer Facility at Woods Hole Oceanographic Institution
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
The Rapid Preparation of Seawater ΣCO 2 for Radiocarbon Analysis at the National Ocean Sciences Ams Facility
We have established a laboratory for extracting ΣCO 2 from seawater samples for AMS analysis of the radiocarbon content. The seawater samples are collected at sea, poisoned and stored until analysis in the laboratory. Each sample is acidified; the inorganic carbon is stripped out as CO 2 with an inert carrier gas and then converted to graphite. We present results for Buzzards Bay surface H 2 O and Na 2 CO 3 standards that demonstrate we strip >98…
Improvements in Procedural Blanks at Nosams
During the four years the Sample Preparation Laboratory (SPL) at the National Ocean Sciences Accelerator Mass Spectrometer (NOSAMS) Facilty has been in operation we have accumulated much data from which we can assess our progress. We evaluate our procedural blanks here and describe modifications in our procedures that have improved our analyses of older samples. In the SPL, we convert three distinct types of samples—seawater, CaCO 3 and organic c…
Measurements of the Oxalic Acid II/Oxalic Acid I Ratio as a Quality Control Parameter at Nosams
Precision of AMS single-target measurements is usually based on counting statistics and variance during the data acquisition cycle. Additional longer-term variability may be studied by looking at the variability of the standards from cycle to cycle
Woce AMS Radiocarbon I
AMS radiocarbon results from the World Ocean Circulation Experiment in the Pacific Ocean show dramatic changes in the inventory and distribution of bomb-produced 14 C since the time of the GEOSECS survey (8/73–6/74). Near-surface Δ 14 C values for the eastern portion of both the northern and southern subtropical gyres decreased by 25–50‰, with the change being greater in the north. Equatorial near-surface values have increased by ca. 25‰. Changes…
The Radiocarbon Content of Individual Lignin-Derived Phenols
We present a method for the isolation of phenolic compounds derived from lignin for radiocarbon analysis. These phenols are generated by chemical oxidation of polymeric materials and derivatized for separation and recovery by preparative capillary gas chromatography (PCGC). This technique yields tens of micrograms of pure, stable compounds that can be converted to graphite and analyzed by accelerator mass spectrometry (AMS). Analysis of model fla…
Converting AMS Data to Radiocarbon Values
We summarize the basic operation of accelerator mass spectrometry (AMS) systems used to measure radiocarbon and discuss the calculations used to convert AMS output to 14 C data
Woce Radiocarbon IV
The World Ocean Circulation Experiment, carried out between 1990 and 1997, provided the most comprehensive oceanic survey of radiocarbon to date. Approximately 10,000 samples were collected in the Pacific Ocean by U.S. investigators for both conventional large volume p counting and small volume accelerator mass spectrometry analysis techniques. Results from six cruises are presented. The data quality is as good or better than previous large-scale…
A High-Performance 14 C Accelerator Mass Spectrometry System
A new and unique radiocarbon accelerator mass spectrometry (AMS) facility has been constructed at the Woods Hole Oceanographic Institution. The defining characteristic of the new system is its large-gap optical elements that provide a larger-than-standard beam acceptance. Such a system is ideally suited for high-throughput, high-precision measurements of 14 C. Details and performance of the new system are presented
Intercomparison of 14 C Analysis of Carbonaceous Aerosols
Radiocarbon analysis of the carbonaceous aerosol allows an apportionment of fossil and non-fossil sources of airborne particulate matter (PM). A chemical separation of total carbon (TC) into its subtractions organic carbon (OC) and elemental carbon (EC) refines this powerful technique, as OC and EC originate from different sources and undergo different processes in the atmosphere. Although 14 C analysis of TC, EC, and OC has recently gained incre…
Geology (9 obras) · Radiocarbon dating (8 obras) · Accelerator mass spectrometry (7 obras) · Isotope Analysis in Ecology (7 obras) · Chemistry (6 obras) · Geology and Paleoclimatology Research (5 obras) · Mass spectrometry (5 obras) · Archaeology and ancient environmental studies (4 obras) · Carbon fibers (4 obras) · Environmental Science (4 obras)