Method-sensitivity of in-situ γ spectrometry to determine the depth-distribution of anthropogenic radionuclides in soil

2012 ◽  
Vol 661 (1) ◽  
pp. 26-30 ◽  
Author(s):  
T.C. Feng ◽  
M.Y. Jia ◽  
Y.J. Feng
Keyword(s):  
Depth Distribution ◽  
Anthropogenic Radionuclides ◽  
Γ Spectrometry

scholarly journals The Athens Mobile γ-Spectrometry System (AMESOS)

2019 ◽  
Vol 23 ◽  
pp. 150
Author(s):  
A. Karailias ◽  
V. Lagaki ◽  
C. Katsiva ◽  
A. Kanellakopoulos ◽  
T. J. Mertzimekis ◽  
...  
Keyword(s):  
Absorbed Dose ◽  
In Situ Measurements ◽  
Harsh Environments ◽  
The Public ◽  
Dose Rates ◽  
Field Operation ◽  
Standard Calibration ◽  
Γ Spectrometry ◽  
The University

We report on a new mobile γ-spectrometry system (AMESOS) developed at the University of Athens. The system aims at carrying out in situ measurements to study distributions of NORM and TENORM at harsh environments or where sampling is difficult. AMESOS has been characterized by using standard calibration sources and minerals of known, independently determined, U and Th concentrations. Simulations of the system have been performed with MCNP and Geant4. As a proof of good field operation, AMESOS was deployed in a series of measurements at Mt. Kithaeron, near Athens, extending earlier data and estimating absorbed dose rates that concern the public.

Ontogeny of behaviour relevant to dispersal and connectivity in the larvae of two non-reef demersal, tropical fish species

2009 ◽  
Vol 60 (3) ◽  
pp. 211 ◽  
Author(s):  
Jeffrey M. Leis ◽  
Richard F. Piola ◽  
Amanda C. Hay ◽  
Colin Wen ◽  
Kun-Ping Kan
Keyword(s):  
Depth Distribution ◽  
Size Range ◽  
Reef Fishes ◽  
Population Connectivity ◽  
Marine Fishes ◽  
Tropical Fish ◽  
Larval Behaviour ◽  
Pelagic Larvae ◽  
Geographical Scale

In demersal marine fishes, the dispersal of larvae determines the geographical scale of population connectivity, and larval behaviour may influence dispersal. Yet, little is known of the ontogeny of behaviours that can influence dispersal. The present study examined the development of these behaviours in pelagic larvae of tropical marine fishes (4–21 mm) that occupy non-reef habitats as adults: Eleutheronema tetradactylum (Polynemidae) and Leiognathus equulus (Leiognathidae). In the laboratory, critical speed (Ucrit) increased from 3 to 34 cm s–1 at 1.3–1.7 cm s–1 per mm of size, with the fastest larvae up to 50% faster. In situ speed increased from 4 to 25 cm s–1 at 0.7–2.2 cm s–1 per mm, and was 10–14 body length s–1 (60–90% of Ucrit). Endurance increased from 0 to >40 km at 2.4–4.7 km per mm. In the sea, orientation precision did not change ontogenetically, both species tended to swim in loops, and neither significant overall directionality nor ontogenetic change in orientation was present. Larval orientation of these non-reef species was less precise than that of reef fishes. The two species differed in depth distribution, and one ascended ontogenetically. These behaviours can potentially influence dispersal outcomes over the full size range of these larvae.

FEASIBILITY STUDY ON THE FUSION OF PHITS SIMULATIONS AND THE DLNN ALGORITHM FOR A NEW QUANTITATIVE METHOD OF IN-SITU MULTIPLE-CHANNEL DEPTH DISTRIBUTION SPECTROMETRY

2019 ◽  
Vol 184 (3-4) ◽  
pp. 328-333
Author(s):  
M Sakama ◽  
K Fujimoto ◽  
K Inoue ◽  
M Fukushi ◽  
Y Imajyo ◽  
...  
Keyword(s):  
Quantitative Method ◽  
Depth Distribution ◽  
Soil Layer ◽  
Specific Radioactivity ◽  
Virtual Space ◽  
Radiation Measurement ◽  
Channel Depth ◽  
Multiple Channel ◽  
Γ Ray

Abstract We have recently have developed an in-situ multiple-channel depth distribution spectrometer (DDS) that can easily acquire on-site measurements of the depth distribution of specific radioactivities of Cs-134 and Cs-137 underground. Despite considerable improvements in the hardware developed for this device, the quantitative method for determining of radioactivities with this DDS device cannot yet achieve satisfactory performance for practical use. For example, this method cannot discriminate each γ-ray spectra of Cs-134 and Cs-137 acquired by the 20 thallium-doped caesium iodine CsI(Tl) scintillation crystal detectors of the DDS device from corresponding depth levels of underground soil. Therefore, we have applied deep learning neural network (DLNN) as a novel radiation measurement technique to discriminate the spectra and to determine the specific radioactivities of Cs-134 and Cs-137. We have developed model soil layers on a virtual space in Monte-Carlo based PHITS simulations and transported γ-ray radiation generated from a particular single soil layer or multiple layers as radiation sources; next, we performed PHITS calculations of those specific radioactivity measurements for each soil layer using DDS device based on machine learning via the DLNN algorithm. In this study, we obtained informative results regarding the feasibility of the proposal innovative radiation measurement method for further practical use in on-site applications.

scholarly journals In situ measurements of firn compaction profiles using borehole optical stratigraphy

2011 ◽  
Vol 57 (202) ◽  
pp. 289-294 ◽  
Author(s):  
Robert L. Hawley ◽  
Edwin D. Waddington
Keyword(s):  
Steady State ◽  
Depth Distribution ◽  
Vertical Motion ◽  
Video Camera ◽  
Survey Period ◽  
The Past ◽  
Steady State Model ◽  
Processing Software ◽  
Optical Brightness

AbstractWe have developed a technique in which we use a borehole video camera and post-processing software to make a record of the optical brightness as a function of depth in polar firn. We call this method borehole optical stratigraphy. To measure firn compaction, we note the positions of optical features on the borehole wall detected by an initial ‘baseline’ log. We track the displacements of these features in subsequent logs. The result provides a measurement of the relative vertical motion and thus compaction of the firn over the survey period. We have successfully used this system at Summit, Greenland, to measure the depth distribution of firn column shortening experienced in a borehole over three 1 year periods. The uppermost 30 m of the firn at Summit is compacting as predicted by a simple steady-state model, implying that the firn density profile at Summit is at or close to steady state over the past ∼70 years.

Secondary ion mass spectrometry measurements of volcanic tuffs containing radionuclides from underground nuclear tests

2000 ◽  
Vol 88 (8) ◽  
Author(s):  
T.P. Rose ◽  
D.K. Smith ◽  
D.L. Phinney
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Test Site ◽  
Nevada Test Site ◽  
Anthropogenic Radionuclides ◽  
Close Proximity ◽  
Ion Mass Spectrometry ◽  
Nuclear Tests ◽  
Secondary Ion

The in situ distribution of anthropogenic radionuclides in volcanic tuffs was measured using secondary ion mass spectrometry (SIMS). Samples were obtained from boreholes drilled in close proximity to expended underground nuclear test cavities at the Nevada Test Site, USA. SIMS measurements revealed the presence of

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