Heat flow and surface radioactivity in the Quirke Lake Syncline near Elliot Lake, Ontario, Canada

1968 ◽  
Vol 5 (6) ◽  
pp. 1417-1428 ◽  
Author(s):  
J. H. Sass ◽  
P. G. Killeen ◽  
E. D. Mustonen
Keyword(s):  
Heat Flow ◽  
Heat Production ◽  
Gamma Ray ◽  
Average Rate ◽  
Structural Effects ◽  
Gamma Ray Spectrometer ◽  
A Value ◽  
The Mean ◽  
Data Yield ◽  
Ore Zones

Heat flow was measured in seven diamond-drilled holes, ranging in depth from 300 to 900 m, in the Quirke Lake Syncline (82° 30′ W, 46° 30′ N, mean elevation 370 m), Values for individual holes vary from 1.20 to 1.40 with a mean of 1.32 ± 0.02 μcal/cm2s, and no systematic variation was detected within the 50 km2 area studied. Radiometric measurements with a portable, three-channel, gamma-ray spectrometer show a downward concentration (stratigraphically) of Th, U, and K within the lower part of the syncline, with mean concentrations of 12.7 ppm, 3.3 ppm, and 1.9%, respectively. These data yield an average rate of heat production of 4.5 heat generation units (1 hgu = 10−13 cal/cm3s). Taking account of the ore zones, the mean heat production from the syncline is about 6 hgu. Corrections for structural effects and heat production from the ore result in a value of 1.2 for the regional heat flow. This is within the range of other shield values, although somewhat higher than the average for the Canadian Shield. The high value is readily explained if the observed mean surface radioactivity persists to a depth of 7 to 10 km.

Heat Production Measurement in Rocks using a Gamma Ray Spectrometer with a Solid State Detector

1974 ◽  
Vol 11 (4) ◽  
pp. 526-532 ◽  
Author(s):  
Trevor Lewis
Keyword(s):  
Solid State ◽  
Heat Production ◽  
Gamma Ray ◽  
Average Rate ◽  
Counting Efficiency ◽  
United States Geological Survey ◽  
Solid State Detector ◽  
Gamma Ray Spectrometer ◽  
Absorption Correction ◽  
State Detector

A gamma-ray spectrometer with a solid state detector is described for routine laboratory measurement of U, Th, and K in rocks. The results are used to determine their average rate of heat production. The liquid-nitrogen cooled Ge(Li) detector is used in preference to the conventional NaI detector, even though its counting efficiency is much lower, because its much better resolution permits the isolation of low energy peaks. Using the spectrum obtained over the larger energy range, concentrations can be determined to the same accuracy as with the NaI detector in comparable times. Two analysis techniques were used: the first compares the sample's entire spectrum to those from standards. The alternative technique compares only the sharply resolved peaks measured above the continuum: the counting efficiency is reduced but the sample density can vary as long as a self-absorption correction is made. The results on four United States Geological Survey standard rocks are given.With such a system having a high resolution, the U concentration can be measured using the 63 kev gamma-rays produced in the decay of 234Th to 234Pa, thus indicating whether or not the U series is in equilibrium.

Deep Drill 1972. Heat Flow and Heat Production in Bermuda

1974 ◽  
Vol 11 (6) ◽  
pp. 809-818 ◽  
Author(s):  
R. D. Hyndman ◽  
G. K. Muecke ◽  
F. Aumento
Keyword(s):  
Heat Flux ◽  
Heat Flow ◽  
Heat Production ◽  
Land Surface ◽  
Gamma Ray ◽  
Gamma Ray Spectrometry ◽  
Geothermal Heat ◽  
Sea Floor ◽  
Average Value ◽  
The Mean

The geothermal heat flux determined in a borehole on Bermuda is 1.36 μcal/cm2 s (57 mW/m2). The value is corrected for the topographic effect of the Bermuda sea-mount and the difference between sea floor and land surface temperatures. Radioactive heat production in the borehole core determined by gamma-ray spectrometry has an average value of 1.45 × 10−13 cal/cm3 s (6.11 × 10−7 W/m3). Of the altered tholeiite flows and intrusive lamprophyric sheets which make up the section to 800 m, the sheets have 10 times the heat production of the flows. If the heat production attributable to the Bermuda seamount is subtracted from the measured heat flux a value of 1.26 μcal/cm2 s (53 mW/m2) is obtained which is in good agreement with the mean of surrounding sea floor measurements and with the mean for Cretaceous ocean floor. The low heat flow and the small amount of subsidence substantiates the radioactive dating data which indicates the present seamount structure was produced about 33 m.y. ago by intrusion and uplift of a much older structure.

scholarly journals Low-background, digital gamma-ray spectrometer with BEGe detector and active shield: commissioning, optimisation and software development

2019 ◽  
Vol 322 (3) ◽  
pp. 1311-1321
Author(s):  
Krzysztof Gorzkiewicz ◽  
Jerzy Wojciech Mietelski ◽  
Renata Kierepko ◽  
Kamil Brudecki
Keyword(s):  
Gamma Ray ◽  
Germanium Detector ◽  
Low Background ◽  
Gamma Ray Spectrometer ◽  
Annihilation Peak ◽  
The Mean ◽  
Plastic Scintillators ◽  
Set Up ◽  
Active Shield ◽  
Broad Energy

Abstract This paper presents results of the development process of low-background, digital gamma-rays spectrometer equipped with Broad Energy Germanium detector (CANBERRA BE5030), multi-layer passive shield and cosmic veto system that consists of five plastic scintillators (SCIONIX EJ-200). Data acquisition is performed using digitizer CAEN DT5725 with CoMPASS software. Output data analysis is carried out with purposely written and developed code VETO. On the basis of conducted tests, acquisition parameters were set up and tuned as well as time delays between all detectors were established. As a result of the configuration process, the mean background counts reduction of 64% in the whole spectrum and 65% in annihilation peak were achieved. This procedure allowed diminishing detection limits of selected isotopes 37% on average.

scholarly journals Assessing the Radiological Risks Associated with High Natural Radioactivity of Microgranitic Rocks: A Case Study in a Northeastern Desert of Egypt

2022 ◽  
Vol 19 (1) ◽  
pp. 473
Author(s):  
Neveen S. Abed ◽  
Mohamed Abdel Monsif ◽  
Hesham M. H. Zakaly ◽  
Hamdy A. Awad ◽  
Mahmoud M. Hessien ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Fuel Cycle ◽  
Radiological Hazard ◽  
United Nations Scientific Committee ◽  
Southeastern Part ◽  
Gamma Ray Spectrometer ◽  
Activity Concentrations ◽  
Radiological Hazards ◽  
The Mean

This study aimed to evaluate the radiological hazards of uranium (238U), thorium (232Th), and potassium (40K) in microgranitic rocks from the southeastern part of Wadi Baroud, a northeastern desert of Egypt. The activity concentrations of the measured radionuclides were determined by using a gamma-ray spectrometer (NaI-Tl-activated detector). The mean (238U), (232Th), and (40K) concentrations in the studied rocks were found to be 3680.3, 3635.2, and 822.76 Bq/kg, respectively. The contents in these rocks were elevated, reaching up to 6.3 wt%. This indicated the alkaline nature of these rocks. The high ratios of Th/U in the mineralized rocks could be related to late magmatic mineralization, suggesting the ascent of late magmatic fluids through weak planes such as faults and the contact of these rocks with older granites. The present data were higher than those of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) guideline limits. All the radiological hazard results indicated high human health risks. This confirmed that this area is not radiologically safe, and care must be taken when working in this area. This study showed that the area under investigation had high U content suitable for uranium extraction that could be used in the nuclear fuel cycle.

Analysis of Heat Flow Data–Vertical Variations of Heat Flow and Heat Producing Elements in Sediments

1975 ◽  
Vol 12 (6) ◽  
pp. 996-1005 ◽  
Author(s):  
V. M. Hamza ◽  
A. E. Beck
Keyword(s):  
Heat Flow ◽  
Heat Production ◽  
Gamma Ray ◽  
Detailed Examination ◽  
Uranium Content ◽  
Thermal Resistivity ◽  
Geochemical Reactions ◽  
Vertical Variations ◽  
Heat Flow Variations

Gamma ray spectrometric techniques have been used for the determination of uranium, thorium and potassium contents from cores selected at 3 to 4 m intervals from a 600 m deep borehole in sedimentary formations and the results compared with a similarly detailed examination of heat flow, and some physical properties, from the same borehole.The results indicate a broad positive correlation between thermal resistivity and some of the radio-element parameters and between heat flow and heat production. The heat production variations down the borehole are not quantitatively sufficient to explain the observed heat flow variations. The uranium series appears to be in radioactive equilibrium even in those sections where the uranium content is low, the porosity relatively high and the heat flow low; it is therefore concluded that the depletion of uranium is due to an ancient rather than a recent leaching process and that it is unlikely that the heat flow variations along the borehole are due to existing or recent underground waterflows. Long term geochemical reactions are now thought to be the most likely explanation of the heat flow variations.

LIFETIMES OF THE 16O 6.13-MeV LEVEL AND THE 17O 0.871-MeV LEVEL

1965 ◽  
Vol 43 (9) ◽  
pp. 1563-1573 ◽  
Author(s):  
T. K. Alexander ◽  
K. W. Allen
Keyword(s):  
Doppler Shift ◽  
Gamma Ray ◽  
Doppler Shift Attenuation ◽  
The Mean ◽  
Data Yield ◽  
Gamma Ray Detector ◽  
Mean Lifetimes

The mean lifetimes of the 0.871-MeV state of 17O(E2) and the 6.13-MeV state of 16O(E3) have been measured by a new recoil method using a Ge(Li) gamma-ray detector. The data yield mean lifetimes of (2.33 ± 0.27) × 10−10 and (2.5 ± 0.2) × 10−11 sec for the states in 17O and 16O respectively. The recoil method is generally applicable to the measurement of lifetimes greater than about 5 × 10−12 sec and provides a technique for a region of time where neither direct electronic timing nor Doppler-shift attenuation methods are accurate.

Geothermal measurements in Newfoundland

1980 ◽  
Vol 17 (10) ◽  
pp. 1370-1376 ◽  
Author(s):  
J. A. Wright ◽  
A. M. Jessop ◽  
A. S. Judge ◽  
T. J. Lewis
Keyword(s):  
Heat Flow ◽  
Heat Production ◽  
Eastern United States ◽  
Maritime Provinces ◽  
Heat Flows ◽  
Iapetus Ocean ◽  
Data Yield ◽  
Orogenic Belts ◽  
Oceanic Rocks ◽  
Reduced Heat Flow

We report heat flow values for ten holes at five sites in Newfoundland. The average observed heat flow is 43 ± 4 mW m−2. Corrected for Pleistocene surface temperature variations, the average becomes 50 ± 4 mW m−2, with a range from 38–82 mW m−2. The Dunnage zone (a vestige of the Iapetus Ocean) exhibits a heat flow lower than normal for Paleozoic orogenic belts. The highest heat flow is associated with the Carboniferous St. Lawrence granite intrusion. Heat production measurements were made at three of the sites. Those in the Dunnage zone are low (< 0.8 μW m−3), as expected for former oceanic rocks, while that for the St. Lawrence granite is high (4.9 μW m−3). A plot of heat flow versus heat production for these data and the data of Hyndman et al. for the Maritime Provinces demonstrates that Newfoundland belongs to the same heat flow province as the Maritimes and the eastern United States. The reduced heat flow for the Canadian Atlantic Provinces data is 32 ± 3 mW m−2, uncorrected, and 40 ± 3 mW m−2 when corrected for Pleistocene temperature effects. Computed geotherms for heat flows and heat productions corresponding to the upper and lower observed limits of the data yield temperatures at 30 km depth of about 575 and 475 °C respectively.

the effects of resonance with Jupiter in the system of short-period comets

1974 ◽  
Vol 22 ◽  
pp. 193-203
Author(s):  
L̆ubor Kresák
Keyword(s):  
Structural Effects ◽  
Order Resonance ◽  
Mean Motion ◽  
Short Period ◽  
The Mean ◽  
Compound Effect ◽  
Low Order

AbstractStructural effects of the resonance with the mean motion of Jupiter on the system of short-period comets are discussed. The distribution of mean motions, determined from sets of consecutive perihelion passages of all known periodic comets, reveals a number of gaps associated with low-order resonance; most pronounced are those corresponding to the simplest commensurabilities of 5/2, 2/1, 5/3, 3/2, 1/1 and 1/2. The formation of the gaps is explained by a compound effect of five possible types of behaviour of the comets set into an approximate resonance, ranging from quick passages through the gap to temporary librations avoiding closer approaches to Jupiter. In addition to the comets of almost asteroidal appearance, librating with small amplitudes around the lower resonance ratios (Marsden, 1970b), there is an interesting group of faint diffuse comets librating in characteristic periods of about 200 years, with large amplitudes of about±8% in μ and almost±180° in σ, around the 2/1 resonance gap. This transient type of motion appears to be nearly as frequent as a circulating motion with period of revolution of less than one half that of Jupiter. The temporary members of this group are characteristic not only by their appearance but also by rather peculiar discovery conditions.

THE EFFECT OF ALTERATION OF THYROXINE BINDING CAPACITY ON THE DIALYZABLE AND ABSOLUTE FRACTIONS OF TRIIODOTHYRONINE IN CIRCULATION

1973 ◽  
Vol 72 (2) ◽  
pp. 265-271 ◽  
Author(s):  
J. H. Dussault ◽  
D. A. Fisher ◽  
J. T. Nicoloff ◽  
V. V. Row ◽  
R. Volpe
Keyword(s):  
Correlation Coefficient ◽  
Inverse Relationship ◽  
Binding Capacity ◽  
Hormone Concentration ◽  
Thyroxine Binding Globulin ◽  
Serum Thyroxine ◽  
A Value ◽  
The Mean ◽  
Male Subjects ◽  
Female Subjects

ABSTRACT In order to determine the effect of alterations in binding capacity of thyroxine binding globulin (TBG) on triiodothyronine (T3) metabolism, studies were conducted in 10 patients with idiopathically low (7 subjects) or elevated (3 subjects) TBG levels and 10 subjects given norethandrolone (7 male subjects) or oestrogen (3 female subjects). Measurements of serum thyroxine (T4) concentration, maximal T4 binding capacity, serum T3 concentration and per cent dialyzable T3 were conducted. Serum T3 was measured both by chemical and radioimmunoassay methods. In patients with idiopathically low TBG, the mean serum T4 concentration was low (2.4 μg/100 ml), the mean serum T3 level low (55 ng/100 ml), the mean per cent dialyzable T3 increased (0.52%), and the calculated free T3 concentration normal (186 pg/100 ml). In patients with idiopathically high TBG levels the mean T4 concentration was high (10.3 μg/100 ml), the mean T3 level slightly elevated (127 ng/100 ml), the% dialyzable T3 low (0.10%) and the calculated free T3 concentration low normal (123 pg/100 ml). The correlation coefficient between the per cent dialyzable T3 and maximal TBG binding capacity in the 20 subjects was 0.68, a value significant at the P < 0.01 level. Thus, alterations in binding capacity of TBG seem to influence T3 and T4 metabolism similarly; the inverse relationship between the % of dialyzable hormone and total hormone concentration tends to keep the absolue levels of free hormones stable.

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