F H Schmidt
Biographic Data
| ID | 5597693 |
|---|---|
| NAME | F H Schmidt |
| GIVEN NAMES | F H |
| FAMILY NAME | Schmidt |
| SIGNATURE | SCHMIDT F H |
| VERIFIED | No |
| TOTAL WORKS | 7 |
| TOTAL CITATIONS | 36 |
| AUTHOR COUNT | 7 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1980 |
| LATEST PUBLICATION YEAR | 1993 |
| H-INDEX | 4 |
Intra-Annual Variability of the Radiocarbon Content of Corals from the Galapagos Islands
We report AMS 14 C measurements on subannual samples of coral from the Galapagos Islands that span the period, 1970–1973. Both the major 1972 El Niño/Southern Oscillation event and intra-annual changes in regional upwelling of 14 C-depleted waters associated with alternation of surface-ocean current patterns are evident in the record. Our data show that the corals preserve a detailed record of past intra-annual variations of the 14 C content of s…
Radiocarbon AMS Dating of Pollen Extracted from Peat Samples
We present 14 C AMS measurements and discuss the extraction procedure used on pollen extracted from peat samples. Microscopic examination of the extracts shows that the procedure is sufficient to remove most non-pollen materials and results in an extract that is composed predominantly of pollen. The 14 C dates that we obtained for pollen extracts from peat samples associated with the Mazama Ash layer are consistent with the range of bulk-sample d…
Importance of Biospheric Co2 in a Subcanopy Atmosphere Deduced From 14C AMS Measurements
14 C concentrations in the stem cellulose of a Sitka spruce from the Pacific coast of Washington respond to changes in atmospheric 14 CO 2 concentration within 5–6 weeks. δ 14 C values for cellulose were consistently lower than those of the corresponding clean troposphere during rapid increase in atmospheric 14 C caused by nuclear weapons tests (1962–64). Possible reasons for this include: 1) a delay of days or weeks in incorporation of recent ph…
Technological Advances in the University of Washington Accelerator Mass Spectrometry System
During the past year we have continued to work toward greater stability and flexibility in nearly all elements of our accelerator mass spectrometry (AMS) system, which is based upon an FN tandem Van de Graaff accelerator, and have carried out measurements of 14 C/ 12 C and 10 Be/ 9 Be isotopic abundance ratios in natural samples. The principal recent developments and improvements in the accelerator system and in our sample preparation techniques …
Current 14 C Measurements with the University of Washington FN Tandem Accelerator
Our accelerator mass spectrometry (AMS) system shows a one-to-one relationship between sample 14 C concentrations determined by AMS - and by β-counting. Measurements of unknown samples against a standard indicate that 14 C concentration measurements to better than 2% can be made. For a 30-second data collection interval in a typical run of 100 intervals, the variability of the beam injected into the accelerator is ca 2%, that of the machine trans…
Enrichment of 14 C and Sample Preparation for Beta and Ion Counting
We here report on two technical research projects of the Quaternary Isotope Laboratory (QL) vis , (1) the use of thermal diffusion isotopic enrichment to extend the technical range of 14 C dating, (2) the preparation of samples for ion counting using a Van de Graaff tandem accelerator. The second project is carried out in cooperation with, and partly at, the Nuclear Physics Laboratory. A gain in dating range of 3 to 4 half-lives can routinely be …
Radiometric Dating with the University of Washington Tandem Van De Graaff Accelerator
The University of Washington Model FN tandem Van de Graaff accelerator is being used for the measurement of extremely small isotopic abundance ratios, notably 14 C/ 12 C and 10 Be/ 9 Be, in a joint project of the Nuclear Physics Laboratory (NPL) and the Quaternary Isotope Laboratory (QL). The experimental arrangements and technical developments are described, and some preliminary results on isotopic ratios in carbon and beryllium are presented
Radiocarbon AMS Dating of Pollen Extracted from Peat Samples
We present 14 C AMS measurements and discuss the extraction procedure used on pollen extracted from peat samples. Microscopic examination of the extracts shows that the procedure is sufficient to remove most non-pollen materials and results in an extract that is composed predominantly of pollen. The 14 C dates that we obtained for pollen extracts from peat samples associated with the Mazama Ash layer are consistent with the range of bulk-sample d…
Intra-Annual Variability of the Radiocarbon Content of Corals from the Galapagos Islands
We report AMS 14 C measurements on subannual samples of coral from the Galapagos Islands that span the period, 1970–1973. Both the major 1972 El Niño/Southern Oscillation event and intra-annual changes in regional upwelling of 14 C-depleted waters associated with alternation of surface-ocean current patterns are evident in the record. Our data show that the corals preserve a detailed record of past intra-annual variations of the 14 C content of s…
Enrichment of 14 C and Sample Preparation for Beta and Ion Counting
We here report on two technical research projects of the Quaternary Isotope Laboratory (QL) vis , (1) the use of thermal diffusion isotopic enrichment to extend the technical range of 14 C dating, (2) the preparation of samples for ion counting using a Van de Graaff tandem accelerator. The second project is carried out in cooperation with, and partly at, the Nuclear Physics Laboratory. A gain in dating range of 3 to 4 half-lives can routinely be …
Importance of Biospheric Co2 in a Subcanopy Atmosphere Deduced From 14C AMS Measurements
14 C concentrations in the stem cellulose of a Sitka spruce from the Pacific coast of Washington respond to changes in atmospheric 14 CO 2 concentration within 5–6 weeks. δ 14 C values for cellulose were consistently lower than those of the corresponding clean troposphere during rapid increase in atmospheric 14 C caused by nuclear weapons tests (1962–64). Possible reasons for this include: 1) a delay of days or weeks in incorporation of recent ph…
Current 14 C Measurements with the University of Washington FN Tandem Accelerator
Our accelerator mass spectrometry (AMS) system shows a one-to-one relationship between sample 14 C concentrations determined by AMS - and by β-counting. Measurements of unknown samples against a standard indicate that 14 C concentration measurements to better than 2% can be made. For a 30-second data collection interval in a typical run of 100 intervals, the variability of the beam injected into the accelerator is ca 2%, that of the machine trans…
Radiometric Dating with the University of Washington Tandem Van De Graaff Accelerator
The University of Washington Model FN tandem Van de Graaff accelerator is being used for the measurement of extremely small isotopic abundance ratios, notably 14 C/ 12 C and 10 Be/ 9 Be, in a joint project of the Nuclear Physics Laboratory (NPL) and the Quaternary Isotope Laboratory (QL). The experimental arrangements and technical developments are described, and some preliminary results on isotopic ratios in carbon and beryllium are presented
Technological Advances in the University of Washington Accelerator Mass Spectrometry System
During the past year we have continued to work toward greater stability and flexibility in nearly all elements of our accelerator mass spectrometry (AMS) system, which is based upon an FN tandem Van de Graaff accelerator, and have carried out measurements of 14 C/ 12 C and 10 Be/ 9 Be isotopic abundance ratios in natural samples. The principal recent developments and improvements in the accelerator system and in our sample preparation techniques …
Enrichment of 14 C and Sample Preparation for Beta and Ion Counting
We here report on two technical research projects of the Quaternary Isotope Laboratory (QL) vis , (1) the use of thermal diffusion isotopic enrichment to extend the technical range of 14 C dating, (2) the preparation of samples for ion counting using a Van de Graaff tandem accelerator. The second project is carried out in cooperation with, and partly at, the Nuclear Physics Laboratory. A gain in dating range of 3 to 4 half-lives can routinely be …
Radiometric Dating with the University of Washington Tandem Van De Graaff Accelerator
The University of Washington Model FN tandem Van de Graaff accelerator is being used for the measurement of extremely small isotopic abundance ratios, notably 14 C/ 12 C and 10 Be/ 9 Be, in a joint project of the Nuclear Physics Laboratory (NPL) and the Quaternary Isotope Laboratory (QL). The experimental arrangements and technical developments are described, and some preliminary results on isotopic ratios in carbon and beryllium are presented
Technological Advances in the University of Washington Accelerator Mass Spectrometry System
During the past year we have continued to work toward greater stability and flexibility in nearly all elements of our accelerator mass spectrometry (AMS) system, which is based upon an FN tandem Van de Graaff accelerator, and have carried out measurements of 14 C/ 12 C and 10 Be/ 9 Be isotopic abundance ratios in natural samples. The principal recent developments and improvements in the accelerator system and in our sample preparation techniques …
Current 14 C Measurements with the University of Washington FN Tandem Accelerator
Our accelerator mass spectrometry (AMS) system shows a one-to-one relationship between sample 14 C concentrations determined by AMS - and by β-counting. Measurements of unknown samples against a standard indicate that 14 C concentration measurements to better than 2% can be made. For a 30-second data collection interval in a typical run of 100 intervals, the variability of the beam injected into the accelerator is ca 2%, that of the machine trans…
Importance of Biospheric Co2 in a Subcanopy Atmosphere Deduced From 14C AMS Measurements
14 C concentrations in the stem cellulose of a Sitka spruce from the Pacific coast of Washington respond to changes in atmospheric 14 CO 2 concentration within 5–6 weeks. δ 14 C values for cellulose were consistently lower than those of the corresponding clean troposphere during rapid increase in atmospheric 14 C caused by nuclear weapons tests (1962–64). Possible reasons for this include: 1) a delay of days or weeks in incorporation of recent ph…
Radiocarbon AMS Dating of Pollen Extracted from Peat Samples
We present 14 C AMS measurements and discuss the extraction procedure used on pollen extracted from peat samples. Microscopic examination of the extracts shows that the procedure is sufficient to remove most non-pollen materials and results in an extract that is composed predominantly of pollen. The 14 C dates that we obtained for pollen extracts from peat samples associated with the Mazama Ash layer are consistent with the range of bulk-sample d…
Intra-Annual Variability of the Radiocarbon Content of Corals from the Galapagos Islands
We report AMS 14 C measurements on subannual samples of coral from the Galapagos Islands that span the period, 1970–1973. Both the major 1972 El Niño/Southern Oscillation event and intra-annual changes in regional upwelling of 14 C-depleted waters associated with alternation of surface-ocean current patterns are evident in the record. Our data show that the corals preserve a detailed record of past intra-annual variations of the 14 C content of s…
Geology (7 works) · Radiocarbon dating (7 works) · Chemistry (6 works) · Physics (5 works) · Accelerator mass spectrometry (4 works) · Materials Science (4 works) · Nuclear physics (4 works) · Nuclear Physics and Applications (4 works) · Paleontology (4 works) · Radiochemistry (4 works)