Henry Polach
Biographic Data
| ID | 5599241 |
|---|---|
| NAME | Henry Polach |
| GIVEN NAMES | Henry |
| FAMILY NAME | Polach |
| SIGNATURE | POLACH H |
| AFFILIATIONS | Australian National University |
| VERIFIED | No |
| TOTAL WORKS | 12 |
| TOTAL CITATIONS | 36 |
| AUTHOR COUNT | 12 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1972 |
| LATEST PUBLICATION YEAR | 1989 |
| H-INDEX | 3 |
Liquid Scintillation 14C Spectrometry
Liquid scintillation (LS) 14 C spectrometry, using ultra low-level, high-efficiency and resolution α and β particle detection equipment is seen as an excellent tool supporting future 14 C radiometry. Modern technology ensures electronic excellence: high-precision, small-sample (100mg) dating ability, flexibility of use for the detection of α and β particle emitting radioisotopes at and below natural abundance levels. Multiple applications to envi…
Care
The need for and means of achieving a 14 C dating quality assurance service are debated
Radon Elimination During Benzene Preparation for Radiocarbon Dating by Liquid Scintillation Spectrometry
Radon gas is a serious contaminant in radiocarbon dating by radiometry. The low specific ionizations associated with the α-particle emitting radon and its β-particle emitting daughters overlap within the 14 C counting window. Elimination of radon is therefore imperative for precise 14 C age determinations. This paper deals with the sources and mechanism of incorporation of radon affecting 14 C dating by liquid scintillation (LS) counting, and rev…
Small Sample 14 C Dating by Liquid Scintillation Spectrometry
Small sample 14 C dating is tested using conventional as well as high-resolution low-level liquid scintillation (LS) spectrometers. Contrasted are the results obtained dating ∼25, 125 and 250mg of elemental carbon in standard size counting vials (3mL) and 0.3mL teflon and quartz vials. It is demonstrated that the improved performance of the 0.3mL counting vials enables just adequate resolution of 25mg and very good resolution of 100mg carbon samp…
Determination of Radon by Liquid Scintillation α / β Particle Spectrometry
Traces of uranium and radium within the 14 C sample generate radon (Rn) which gets occluded during the benzene synthesis, thus generating false (extra) counts within the 14 C counting window. This, if undetected, gives rise to erroneous 14 C age determinations. The application of simultaneous α and β liquid scintillation spectrometry will enable a mathematical evaluation of the 14 C signal unaffected by α and β particle emissions from radon decay…
Validity of 14 C Ages of Carbonates in Sediments
This review is based on geologic surveys carried out in Australia and China as well as on more than 300 14 C dates published in Radiocarbon , Evaluated are the origins and pathways of carbonate formation, stable isotopic composition, carbonate nodule growth rates and paleo-climatic effects. The three identified δ 13 C abundance peaks are unrelated to environment and carbon source whilst 14 C ages group themselves into periods corresponding to pas…
Time Series Analysis of Low Level Gas Counting Data
We demonstrate the feasibility of pulse time of arrival information for early detection of periodic events in low level counting. Time of arrival data allows us to apply time series analysis and serial correlation tests which, in graphic form, give the user an illustrative view of the parameters affecting the validity of counting statistics. The decision to discontinue counting can already be made on the basis of less than 100 counts from the tim…
An Evaluation of Shielding Characteristics Applicable to Mini-Gas Proportional-Counter-Based 14 C Dating Systems
A mini-gas-proportional counter prototype of 10ml capacity (at NTP) was constructed of oxygen-free Finnish copper. The counter tube will be one of 16 equivalent tubes of a small-sample gas counting system, which is equipped with passive graded shield made of lead, cadmium, and copper and a dual active anticoincidence shield, consisting of an external cosmic gas-proportional and an internal plastic scintillation guard. The aim of this study was to…
ANU Radiocarbon Date List X
14 C ages were obtained for the Australian lakes recorded below in order to complement research into their magnetic stratigraphy and sedimentology. It has been possible to establish precise 14 C chronologies in six separate lakes, and also to compare ages obtained from stratigraphically equivalent horizons in different parts of the same lake so as to determine the reproducibility of these ages
Contemporary 14 C Levels and Their Significance to Sedimentary History of Bega Swamp, New South Wales
Atmospheric 14 C variations in nature, as previously documented for the Southern Hemisphere by studies carried out in South Africa and New Zealand, were supplemented by 14 C concentration measurements of wheat-grain samples collected in southeastern New South Wales. Our measurements cover the critical period of 1945/46 up to 1956/57, and span the transition of Suess and atom-bomb effects. The observed variations can be followed quite precisely in…
ANU Radiocarbon Date List V
The present date list contains only details of C 14 measurements on sites selected for archaeomagnetic study. Except where otherwise stated in the text, all samples were collected in 1970 or 1971 during fieldwork by one of the authors (M.B.), and were pretreated with hot 2N HCl to remove any possible contamination by pedogenic carbonate. Benzene samples were prepared using updated synthesis techniques (Polach et al. , 1972) and measurements of C …
Some Effects of Partial Recrystallisation on 14C dating Late Pleistocene Corals and Molluscs
The issue of sea level during the last interstadial revolves largely around the problem of achieving reliable 14 C dates for shell carbonate from Late Pleistocene shallow marine and littoral deposits. A set of 27 samples were collected from Late Pleistocene reefs in New Guinea, and measurements made of 13 C, 14 C, plus the degree of recrystallisation (determined by X-ray diffraction). The original fibrous aragonite structure of the samples (coral…
Care
The need for and means of achieving a 14 C dating quality assurance service are debated
Small Sample 14 C Dating by Liquid Scintillation Spectrometry
Small sample 14 C dating is tested using conventional as well as high-resolution low-level liquid scintillation (LS) spectrometers. Contrasted are the results obtained dating ∼25, 125 and 250mg of elemental carbon in standard size counting vials (3mL) and 0.3mL teflon and quartz vials. It is demonstrated that the improved performance of the 0.3mL counting vials enables just adequate resolution of 25mg and very good resolution of 100mg carbon samp…
ANU Radiocarbon Date List V
The present date list contains only details of C 14 measurements on sites selected for archaeomagnetic study. Except where otherwise stated in the text, all samples were collected in 1970 or 1971 during fieldwork by one of the authors (M.B.), and were pretreated with hot 2N HCl to remove any possible contamination by pedogenic carbonate. Benzene samples were prepared using updated synthesis techniques (Polach et al. , 1972) and measurements of C …
Liquid Scintillation 14C Spectrometry
Liquid scintillation (LS) 14 C spectrometry, using ultra low-level, high-efficiency and resolution α and β particle detection equipment is seen as an excellent tool supporting future 14 C radiometry. Modern technology ensures electronic excellence: high-precision, small-sample (100mg) dating ability, flexibility of use for the detection of α and β particle emitting radioisotopes at and below natural abundance levels. Multiple applications to envi…
Radon Elimination During Benzene Preparation for Radiocarbon Dating by Liquid Scintillation Spectrometry
Radon gas is a serious contaminant in radiocarbon dating by radiometry. The low specific ionizations associated with the α-particle emitting radon and its β-particle emitting daughters overlap within the 14 C counting window. Elimination of radon is therefore imperative for precise 14 C age determinations. This paper deals with the sources and mechanism of incorporation of radon affecting 14 C dating by liquid scintillation (LS) counting, and rev…
Determination of Radon by Liquid Scintillation α / β Particle Spectrometry
Traces of uranium and radium within the 14 C sample generate radon (Rn) which gets occluded during the benzene synthesis, thus generating false (extra) counts within the 14 C counting window. This, if undetected, gives rise to erroneous 14 C age determinations. The application of simultaneous α and β liquid scintillation spectrometry will enable a mathematical evaluation of the 14 C signal unaffected by α and β particle emissions from radon decay…
Time Series Analysis of Low Level Gas Counting Data
We demonstrate the feasibility of pulse time of arrival information for early detection of periodic events in low level counting. Time of arrival data allows us to apply time series analysis and serial correlation tests which, in graphic form, give the user an illustrative view of the parameters affecting the validity of counting statistics. The decision to discontinue counting can already be made on the basis of less than 100 counts from the tim…
Contemporary 14 C Levels and Their Significance to Sedimentary History of Bega Swamp, New South Wales
Atmospheric 14 C variations in nature, as previously documented for the Southern Hemisphere by studies carried out in South Africa and New Zealand, were supplemented by 14 C concentration measurements of wheat-grain samples collected in southeastern New South Wales. Our measurements cover the critical period of 1945/46 up to 1956/57, and span the transition of Suess and atom-bomb effects. The observed variations can be followed quite precisely in…
An Evaluation of Shielding Characteristics Applicable to Mini-Gas Proportional-Counter-Based 14 C Dating Systems
A mini-gas-proportional counter prototype of 10ml capacity (at NTP) was constructed of oxygen-free Finnish copper. The counter tube will be one of 16 equivalent tubes of a small-sample gas counting system, which is equipped with passive graded shield made of lead, cadmium, and copper and a dual active anticoincidence shield, consisting of an external cosmic gas-proportional and an internal plastic scintillation guard. The aim of this study was to…
Some Effects of Partial Recrystallisation on 14C dating Late Pleistocene Corals and Molluscs
The issue of sea level during the last interstadial revolves largely around the problem of achieving reliable 14 C dates for shell carbonate from Late Pleistocene shallow marine and littoral deposits. A set of 27 samples were collected from Late Pleistocene reefs in New Guinea, and measurements made of 13 C, 14 C, plus the degree of recrystallisation (determined by X-ray diffraction). The original fibrous aragonite structure of the samples (coral…
ANU Radiocarbon Date List V
The present date list contains only details of C 14 measurements on sites selected for archaeomagnetic study. Except where otherwise stated in the text, all samples were collected in 1970 or 1971 during fieldwork by one of the authors (M.B.), and were pretreated with hot 2N HCl to remove any possible contamination by pedogenic carbonate. Benzene samples were prepared using updated synthesis techniques (Polach et al. , 1972) and measurements of C …
Contemporary 14 C Levels and Their Significance to Sedimentary History of Bega Swamp, New South Wales
Atmospheric 14 C variations in nature, as previously documented for the Southern Hemisphere by studies carried out in South Africa and New Zealand, were supplemented by 14 C concentration measurements of wheat-grain samples collected in southeastern New South Wales. Our measurements cover the critical period of 1945/46 up to 1956/57, and span the transition of Suess and atom-bomb effects. The observed variations can be followed quite precisely in…
An Evaluation of Shielding Characteristics Applicable to Mini-Gas Proportional-Counter-Based 14 C Dating Systems
A mini-gas-proportional counter prototype of 10ml capacity (at NTP) was constructed of oxygen-free Finnish copper. The counter tube will be one of 16 equivalent tubes of a small-sample gas counting system, which is equipped with passive graded shield made of lead, cadmium, and copper and a dual active anticoincidence shield, consisting of an external cosmic gas-proportional and an internal plastic scintillation guard. The aim of this study was to…
ANU Radiocarbon Date List X
14 C ages were obtained for the Australian lakes recorded below in order to complement research into their magnetic stratigraphy and sedimentology. It has been possible to establish precise 14 C chronologies in six separate lakes, and also to compare ages obtained from stratigraphically equivalent horizons in different parts of the same lake so as to determine the reproducibility of these ages
Time Series Analysis of Low Level Gas Counting Data
We demonstrate the feasibility of pulse time of arrival information for early detection of periodic events in low level counting. Time of arrival data allows us to apply time series analysis and serial correlation tests which, in graphic form, give the user an illustrative view of the parameters affecting the validity of counting statistics. The decision to discontinue counting can already be made on the basis of less than 100 counts from the tim…
Validity of 14 C Ages of Carbonates in Sediments
This review is based on geologic surveys carried out in Australia and China as well as on more than 300 14 C dates published in Radiocarbon , Evaluated are the origins and pathways of carbonate formation, stable isotopic composition, carbonate nodule growth rates and paleo-climatic effects. The three identified δ 13 C abundance peaks are unrelated to environment and carbon source whilst 14 C ages group themselves into periods corresponding to pas…
Small Sample 14 C Dating by Liquid Scintillation Spectrometry
Small sample 14 C dating is tested using conventional as well as high-resolution low-level liquid scintillation (LS) spectrometers. Contrasted are the results obtained dating ∼25, 125 and 250mg of elemental carbon in standard size counting vials (3mL) and 0.3mL teflon and quartz vials. It is demonstrated that the improved performance of the 0.3mL counting vials enables just adequate resolution of 25mg and very good resolution of 100mg carbon samp…
Determination of Radon by Liquid Scintillation α / β Particle Spectrometry
Traces of uranium and radium within the 14 C sample generate radon (Rn) which gets occluded during the benzene synthesis, thus generating false (extra) counts within the 14 C counting window. This, if undetected, gives rise to erroneous 14 C age determinations. The application of simultaneous α and β liquid scintillation spectrometry will enable a mathematical evaluation of the 14 C signal unaffected by α and β particle emissions from radon decay…
Liquid Scintillation 14C Spectrometry
Liquid scintillation (LS) 14 C spectrometry, using ultra low-level, high-efficiency and resolution α and β particle detection equipment is seen as an excellent tool supporting future 14 C radiometry. Modern technology ensures electronic excellence: high-precision, small-sample (100mg) dating ability, flexibility of use for the detection of α and β particle emitting radioisotopes at and below natural abundance levels. Multiple applications to envi…
Care
The need for and means of achieving a 14 C dating quality assurance service are debated
Radon Elimination During Benzene Preparation for Radiocarbon Dating by Liquid Scintillation Spectrometry
Radon gas is a serious contaminant in radiocarbon dating by radiometry. The low specific ionizations associated with the α-particle emitting radon and its β-particle emitting daughters overlap within the 14 C counting window. Elimination of radon is therefore imperative for precise 14 C age determinations. This paper deals with the sources and mechanism of incorporation of radon affecting 14 C dating by liquid scintillation (LS) counting, and rev…
Geology (9 works) · Radiocarbon dating (8 works) · Chemistry (7 works) · Geology and Paleoclimatology Research (7 works) · Physics (6 works) · Radiochemistry (6 works) · Archaeology and ancient environmental studies (5 works) · Liquid scintillation counting (5 works) · Archaeology (4 works) · Chromatography (4 works)