Pall Theodórsson
Biographic Data
| ID | 4121612 |
|---|---|
| NAME | Pall Theodórsson |
| GIVEN NAMES | Pall |
| FAMILY NAME | Theodórsson |
| SIGNATURE | THEODÓRSSON P |
| AFFILIATIONS | University of Iceland |
| VERIFIED | No |
| TOTAL WORKS | 13 |
| TOTAL CITATIONS | 25 |
| WORKS AS AUTHOR | 13 |
| WORKS AS EDITOR | 0 |
| FIRST PUBLICATION YEAR | 1989 |
| LATEST PUBLICATION YEAR | 2011 |
| H-INDEX | 4 |
Balanced-Energy Counting Window for Stable Liquid Scintillation Radiocarbon Dating
This paper describes an optimal radiocarbon counting window for liquid scintillation (LS) 14 C dating that secures for unquenched as well as for heavily quenched dating samples maximal stability of 14 C counting efficiency and theoretically minimal quench correction. In high-precision dating, a balanced counting window with fixed channel limits is frequently used, where about 3% of the highest part of the 14 C spectrum is sacrificed for high 14 C…
The Application of Icels Systems for Radiocarbon Dating
Liquid scintillation counting (LSC) for radiocarbon dating is a less expensive method than accelerator mass spectrometry (AMS), provides a high degree of accuracy, and is less prone to contamination due to the larger sample sizes. However, to obtain high precision, a long counting time is needed. The Gliwice Radiocarbon Laboratory is seeking to obtain an increased counting capacity with 2–3 mL benzene samples than we presently can achieve with ou…
A Simple, Extremely Stable Single-Tube Liquid Scintillation System for Radiocarbon Dating
This paper describes a simple and compact liquid scintillation radiocarbon dating system, ICELS, and demonstrates its long-term stability and reproducibility to a precision level rarely presented before, better than 0.04% (3 14 C yr). Inexpensive systems of this kind may, in the future, help to meet increasing demand for high precision (±16 to ±20 14 C yr) and strict quality control. ICELS comprises a compact detector unit, where a 3-mL dome-shap…
Simultaneously Measuring 14 C and Radon in Benzene Dating Samples
After benzene synthesis, radiocarbon dating samples are usually stored for 3–4 weeks before counting to allow an eventual radon contamination to decay to a negligible level. This paper presents a technique that can minimize, and often eliminate, this delay by using a simple single-phototube liquid scintillation counting system, specifically designed for 14 C dating. Radon contamination is assessed by pulses of 214 Po (a 222 Rn decay product, half…
A 23-Year Retrospective Blind Check of Accuracy of the Copenhagen Radiocarbon Dating System
A 23-yr record of the measuring accuracy of the Copenhagen radiocarbon dating laboratory has retrospectively been provided through a true blind test. A total of 92 samples of oak from old tree trunks were dated in the period 1971 to 1993 and their dendrochronological age determined independently. The 14 C activity of the dendrochronological samples measured in the Copenhagen radiocarbon laboratory was compared to the activity of the tree rings of…
Norse settlement of Iceland — close to ad 700
Radiocarbon age determination in the 1970s of some 40 archaeological samples strongly indicates a Norse settlement (landnam) in both Reykjavik and the Westman Islands, Iceland, at about AD 700. This early date has generally been rejected by Icelandic scientists because it contradicts the firmly established dating of the settlement (landnam) at about AD 870. In the present article a critical search for an error in the radiocarbon dating work resul…
Radiometric 14 C Dating
A recent broad study of the background of all types of low-level beta and gamma detectors has now made it possible to analyze its components more reliably and with greater detail. This general analysis is developed further here for gas proportional and liquid scintillation counters used in radiocarbon dating. The background of gas counters, which is dominated by secondary cosmic gamma radiation, is now well understood and can be described quantit…
Stability of a New, Multichannel, Low-Level Liquid Scintillation Counter System, Kvartett
Kvartett is a new liquid scintillation counting (LSC) system for radiocarbon dating that takes a radical departure from conventional systems to obtain a compact, low-level counting system measuring four samples simultaneously. Each sample vial, inside the well of a large NaI(Tl) guard-counter crystal (facing down), sits on top of a vertical PMT. The fourfold counting capacity can be used to increase the number of samples being dated or to get hig…
External Radon Disturbance of 14 C Measurements in Gas-Proportional Counters
Low-level detector systems for 14 C dating are frequently located in underground or basement laboratories to reduce the influence of cosmic radiation. However, if careful precautions are not taken, the presence of radioactive radon gas may severely disturb the analytical results. Measurements of the influence of radon on a proportional counter system, show that a radon level of 100 Bq m −3 , a level not uncommon in basement rooms, is sufficient t…
Quantifying Background Components of Low-Level Gas Proportional Counters
I discuss background components of low-level gas proportional counters and show how each component can be estimated based on available data. For more reliable background analysis, further studies are suggested. Based on new information, a generation of low-level gas proportional counting systems for radiocarbon dating may emerge with lower and more predictable background
Gamma Flux in 14 C Laboratories
An informal collaborative group of radiocarbon dating laboratories, the Low-Level Club, has been established to measure the gamma radiation flux and to test the efficiency of the anticoincidence counting system in laboratories with a NaI detector unit. The detector will record gamma radiation from cosmogenic nuclides, muons and secondary γ radiation formed in the passive shield by charged cosmic-ray particles. We present here the first phase of t…
Gas Proportional Versus Liquid Scintillation Counting, Radiometric Versus AMS Dating
I discuss here the basis of a comparison of methods for radiocarbon dating and introduce a new index for the relative merit of a system, factor of counting capacity, that is generally more appropriate than the commonly used factor of merit. The merit of a dating system cannot be based on a single figure but other factors must also be considered. A comparison of the gas proportional, liquid scintillation and accelerator mass spectrometry technique…
Study of Background Pulse Spectrum of an LSC System
Important advances have been made in reducing the background counting rate of gas proportional counters for 14 C dating through detailed and systematic study of the background components. Until recently, limited work has been reported on the study of the background of liquid scintillation counters (LSC). During the last few years, commercial systems with greatly reduced background have been introduced. It is shown that the best gas proportional c…
A Simple, Extremely Stable Single-Tube Liquid Scintillation System for Radiocarbon Dating
This paper describes a simple and compact liquid scintillation radiocarbon dating system, ICELS, and demonstrates its long-term stability and reproducibility to a precision level rarely presented before, better than 0.04% (3 14 C yr). Inexpensive systems of this kind may, in the future, help to meet increasing demand for high precision (±16 to ±20 14 C yr) and strict quality control. ICELS comprises a compact detector unit, where a 3-mL dome-shap…
Gas Proportional Versus Liquid Scintillation Counting, Radiometric Versus AMS Dating
I discuss here the basis of a comparison of methods for radiocarbon dating and introduce a new index for the relative merit of a system, factor of counting capacity, that is generally more appropriate than the commonly used factor of merit. The merit of a dating system cannot be based on a single figure but other factors must also be considered. A comparison of the gas proportional, liquid scintillation and accelerator mass spectrometry technique…
Norse settlement of Iceland — close to ad 700
Radiocarbon age determination in the 1970s of some 40 archaeological samples strongly indicates a Norse settlement (landnam) in both Reykjavik and the Westman Islands, Iceland, at about AD 700. This early date has generally been rejected by Icelandic scientists because it contradicts the firmly established dating of the settlement (landnam) at about AD 870. In the present article a critical search for an error in the radiocarbon dating work resul…
Quantifying Background Components of Low-Level Gas Proportional Counters
I discuss background components of low-level gas proportional counters and show how each component can be estimated based on available data. For more reliable background analysis, further studies are suggested. Based on new information, a generation of low-level gas proportional counting systems for radiocarbon dating may emerge with lower and more predictable background
Balanced-Energy Counting Window for Stable Liquid Scintillation Radiocarbon Dating
This paper describes an optimal radiocarbon counting window for liquid scintillation (LS) 14 C dating that secures for unquenched as well as for heavily quenched dating samples maximal stability of 14 C counting efficiency and theoretically minimal quench correction. In high-precision dating, a balanced counting window with fixed channel limits is frequently used, where about 3% of the highest part of the 14 C spectrum is sacrificed for high 14 C…
The Application of Icels Systems for Radiocarbon Dating
Liquid scintillation counting (LSC) for radiocarbon dating is a less expensive method than accelerator mass spectrometry (AMS), provides a high degree of accuracy, and is less prone to contamination due to the larger sample sizes. However, to obtain high precision, a long counting time is needed. The Gliwice Radiocarbon Laboratory is seeking to obtain an increased counting capacity with 2–3 mL benzene samples than we presently can achieve with ou…
A 23-Year Retrospective Blind Check of Accuracy of the Copenhagen Radiocarbon Dating System
A 23-yr record of the measuring accuracy of the Copenhagen radiocarbon dating laboratory has retrospectively been provided through a true blind test. A total of 92 samples of oak from old tree trunks were dated in the period 1971 to 1993 and their dendrochronological age determined independently. The 14 C activity of the dendrochronological samples measured in the Copenhagen radiocarbon laboratory was compared to the activity of the tree rings of…
Stability of a New, Multichannel, Low-Level Liquid Scintillation Counter System, Kvartett
Kvartett is a new liquid scintillation counting (LSC) system for radiocarbon dating that takes a radical departure from conventional systems to obtain a compact, low-level counting system measuring four samples simultaneously. Each sample vial, inside the well of a large NaI(Tl) guard-counter crystal (facing down), sits on top of a vertical PMT. The fourfold counting capacity can be used to increase the number of samples being dated or to get hig…
External Radon Disturbance of 14 C Measurements in Gas-Proportional Counters
Low-level detector systems for 14 C dating are frequently located in underground or basement laboratories to reduce the influence of cosmic radiation. However, if careful precautions are not taken, the presence of radioactive radon gas may severely disturb the analytical results. Measurements of the influence of radon on a proportional counter system, show that a radon level of 100 Bq m −3 , a level not uncommon in basement rooms, is sufficient t…
Gamma Flux in 14 C Laboratories
An informal collaborative group of radiocarbon dating laboratories, the Low-Level Club, has been established to measure the gamma radiation flux and to test the efficiency of the anticoincidence counting system in laboratories with a NaI detector unit. The detector will record gamma radiation from cosmogenic nuclides, muons and secondary γ radiation formed in the passive shield by charged cosmic-ray particles. We present here the first phase of t…
Study of Background Pulse Spectrum of an LSC System
Important advances have been made in reducing the background counting rate of gas proportional counters for 14 C dating through detailed and systematic study of the background components. Until recently, limited work has been reported on the study of the background of liquid scintillation counters (LSC). During the last few years, commercial systems with greatly reduced background have been introduced. It is shown that the best gas proportional c…
Study of Background Pulse Spectrum of an LSC System
Important advances have been made in reducing the background counting rate of gas proportional counters for 14 C dating through detailed and systematic study of the background components. Until recently, limited work has been reported on the study of the background of liquid scintillation counters (LSC). During the last few years, commercial systems with greatly reduced background have been introduced. It is shown that the best gas proportional c…
Gas Proportional Versus Liquid Scintillation Counting, Radiometric Versus AMS Dating
I discuss here the basis of a comparison of methods for radiocarbon dating and introduce a new index for the relative merit of a system, factor of counting capacity, that is generally more appropriate than the commonly used factor of merit. The merit of a dating system cannot be based on a single figure but other factors must also be considered. A comparison of the gas proportional, liquid scintillation and accelerator mass spectrometry technique…
Quantifying Background Components of Low-Level Gas Proportional Counters
I discuss background components of low-level gas proportional counters and show how each component can be estimated based on available data. For more reliable background analysis, further studies are suggested. Based on new information, a generation of low-level gas proportional counting systems for radiocarbon dating may emerge with lower and more predictable background
Gamma Flux in 14 C Laboratories
An informal collaborative group of radiocarbon dating laboratories, the Low-Level Club, has been established to measure the gamma radiation flux and to test the efficiency of the anticoincidence counting system in laboratories with a NaI detector unit. The detector will record gamma radiation from cosmogenic nuclides, muons and secondary γ radiation formed in the passive shield by charged cosmic-ray particles. We present here the first phase of t…
Stability of a New, Multichannel, Low-Level Liquid Scintillation Counter System, Kvartett
Kvartett is a new liquid scintillation counting (LSC) system for radiocarbon dating that takes a radical departure from conventional systems to obtain a compact, low-level counting system measuring four samples simultaneously. Each sample vial, inside the well of a large NaI(Tl) guard-counter crystal (facing down), sits on top of a vertical PMT. The fourfold counting capacity can be used to increase the number of samples being dated or to get hig…
External Radon Disturbance of 14 C Measurements in Gas-Proportional Counters
Low-level detector systems for 14 C dating are frequently located in underground or basement laboratories to reduce the influence of cosmic radiation. However, if careful precautions are not taken, the presence of radioactive radon gas may severely disturb the analytical results. Measurements of the influence of radon on a proportional counter system, show that a radon level of 100 Bq m −3 , a level not uncommon in basement rooms, is sufficient t…
Radiometric 14 C Dating
A recent broad study of the background of all types of low-level beta and gamma detectors has now made it possible to analyze its components more reliably and with greater detail. This general analysis is developed further here for gas proportional and liquid scintillation counters used in radiocarbon dating. The background of gas counters, which is dominated by secondary cosmic gamma radiation, is now well understood and can be described quantit…
Norse settlement of Iceland — close to ad 700
Radiocarbon age determination in the 1970s of some 40 archaeological samples strongly indicates a Norse settlement (landnam) in both Reykjavik and the Westman Islands, Iceland, at about AD 700. This early date has generally been rejected by Icelandic scientists because it contradicts the firmly established dating of the settlement (landnam) at about AD 870. In the present article a critical search for an error in the radiocarbon dating work resul…
A 23-Year Retrospective Blind Check of Accuracy of the Copenhagen Radiocarbon Dating System
A 23-yr record of the measuring accuracy of the Copenhagen radiocarbon dating laboratory has retrospectively been provided through a true blind test. A total of 92 samples of oak from old tree trunks were dated in the period 1971 to 1993 and their dendrochronological age determined independently. The 14 C activity of the dendrochronological samples measured in the Copenhagen radiocarbon laboratory was compared to the activity of the tree rings of…
A Simple, Extremely Stable Single-Tube Liquid Scintillation System for Radiocarbon Dating
This paper describes a simple and compact liquid scintillation radiocarbon dating system, ICELS, and demonstrates its long-term stability and reproducibility to a precision level rarely presented before, better than 0.04% (3 14 C yr). Inexpensive systems of this kind may, in the future, help to meet increasing demand for high precision (±16 to ±20 14 C yr) and strict quality control. ICELS comprises a compact detector unit, where a 3-mL dome-shap…
Simultaneously Measuring 14 C and Radon in Benzene Dating Samples
After benzene synthesis, radiocarbon dating samples are usually stored for 3–4 weeks before counting to allow an eventual radon contamination to decay to a negligible level. This paper presents a technique that can minimize, and often eliminate, this delay by using a simple single-phototube liquid scintillation counting system, specifically designed for 14 C dating. Radon contamination is assessed by pulses of 214 Po (a 222 Rn decay product, half…
The Application of Icels Systems for Radiocarbon Dating
Liquid scintillation counting (LSC) for radiocarbon dating is a less expensive method than accelerator mass spectrometry (AMS), provides a high degree of accuracy, and is less prone to contamination due to the larger sample sizes. However, to obtain high precision, a long counting time is needed. The Gliwice Radiocarbon Laboratory is seeking to obtain an increased counting capacity with 2–3 mL benzene samples than we presently can achieve with ou…
Balanced-Energy Counting Window for Stable Liquid Scintillation Radiocarbon Dating
This paper describes an optimal radiocarbon counting window for liquid scintillation (LS) 14 C dating that secures for unquenched as well as for heavily quenched dating samples maximal stability of 14 C counting efficiency and theoretically minimal quench correction. In high-precision dating, a balanced counting window with fixed channel limits is frequently used, where about 3% of the highest part of the 14 C spectrum is sacrificed for high 14 C…
Geology (12 works) · Radiocarbon dating (11 works) · Chemistry (10 works) · Physics (10 works) · Radiochemistry (10 works) · Detector (9 works) · Optics (9 works) · Liquid scintillation counting (8 works) · Nuclear physics (7 works) · Nuclear Physics and Applications (6 works)