The use of the Projected Track Length Distributions of fission tracks in apatite for thermal hisory analysis

1993 ◽  
Vol 21 (4) ◽  
pp. 594
Author(s):  
M. Grivet ◽  
M. Rebetez ◽  
N. Ben Ghouma ◽  
A. Chambaudet ◽  
R. Jonckheere
Keyword(s):  
Track Length ◽  
Fission Tracks

Some calculations relevant to thermal annealing of fission tracks in apatite

1988 ◽  
Vol 419 (1857) ◽  
pp. 305-321 ◽  
Keyword(s):  
Conditional Distribution ◽  
Fission Track ◽  
Length Distribution ◽  
Track Length ◽  
Apatite Crystal ◽  
Routine Practice ◽  
Fission Tracks ◽  
Line Segments ◽  
Segment Model ◽  
Arbitrary Plane

Calculations in stochastic geometry are applied to the geological problem of analysing the statistical distribution of fission tracks in an apatite crystal, when information is available only by plane sampling. The feature of particular interest is the effect of anisotropy, in the sense of dependence of track length on orientation. Using a realistic Poisson line-segment model, we obtain formulae for the density of line segments intersecting an arbitrary plane and for the length distributions of confined tracks, semi-tracks and projected semi-tracks in terms of the conditional distribution of length given orientation. These formulae are used to explain and quantify the effect of anisotropy seen in experimental data from fission track annealing studies. We argue that track orientations, in addition to lengths, carry potentially useful information. For confined tracks, we recommend that both length and angle to the c -axis be measured as routine practice. For projected semi-tracks, where it is much harder to extract useful information from the observed length distribution, the measurement of angle, in addition to length, may prove fruitful, particularly when confined tracks are scarce.

scholarly journals Confined fission-track revelation in apatite: how it works and why it matters

Geochronology ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 433-464
Author(s):  
Richard A. Ketcham ◽  
Murat T. Tamer
Keyword(s):  
Fission Track ◽  
Probability Of Detection ◽  
Theory And Practice ◽  
Track Length ◽  
Underlying Structure ◽  
Fission Tracks ◽  
Fission Track Thermochronology ◽  
Geological Conditions ◽  
Length Measurements ◽  
Along Track

Abstract. We present a new model for the etching and revelation of confined fission tracks in apatite based on variable along-track etching velocity, vT(x). Insights from step-etching experiments and theoretical energy loss rates of fission fragments suggest two end-member etching structures: constant-core, with a central zone of constant etching rate that then falls off toward track tips; and linear, in which etching rates fall linearly from the midpoint to the tips. From these, we construct a characterization of confined track revelation that encompasses all relevant processes, including penetration and widening of semi-tracks etching in from the polished grain surface, intersection with and expansion of confined tracks, and analyst selection of which tracks to measure and which to bypass. Both etching structures are able to fit step-etching data from five sets of paired experiments of fossil tracks and unannealed and annealed induced tracks in Durango apatite, supporting the correctness of our approach and providing a series of insights into the theory and practice of fission-track thermochronology. Etching rates for annealed induced tracks are much faster than those for unannealed induced and spontaneous tracks, impacting the relative efficiency of both confined track length and density measurements and suggesting that high-temperature laboratory annealing may induce a transformation in track cores that does not occur at geological conditions of partial annealing. The model quantifies how variation in analyst selection criteria, summarized as the ratio of along-track to bulk etching velocity at the etched track tip (vT/vB), likely plays a first-order role in the reproducibility of confined length measurements. It also accounts for and provides an estimate of the large proportion of tracks that are intersected but not measured, and it shows how length biasing is likely to be an insufficient basis for predicting the relative probability of detection of different track populations. The vT(x) model provides an approach to optimizing etching conditions, linking track length measurements across etching protocols, and discerning new information on the underlying structure of fission tracks.

scholarly journals Deconvolution of fission-track length distributions and its application to dating and separating pre- and post-depositional components

Geochronology ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 561-575
Author(s):  
Peter Klint Jensen ◽  
Kirsten Hansen
Keyword(s):  
Least Squares ◽  
Covariance Matrix ◽  
Thermal History ◽  
Prior Information ◽  
Fission Track ◽  
Length Distribution ◽  
Track Length ◽  
Fission Tracks ◽  
Apatite Crystals ◽  
Thermal Histories

Abstract. To enable the separation of pre- and postdepositional components of the length distribution of (partially annealed) horizontal confined fission tracks, the length distribution is corrected by deconvolution. Probabilistic least-squares inversion corrects natural track length histograms for observational biases, considering the variance in data, modelization, and prior information. The corrected histogram is validated by its variance–covariance matrix. It is considered that horizontal track data can exist with or without measurements of angles to the c axis. In the latter case, 3D histograms are introduced as an alternative to histograms of c-axis-projected track lengths. Thermal history modelling of samples is not necessary for the calculation of track age distributions of corrected tracks. In an example, the age equations are applied to apatites with predepositional (inherited) tracks in order to extract the postdepositional track length histogram. Fission tracks generated before deposition in detrital apatite crystals are mixed with post-depositional tracks. This complicates the calculation of the post-sedimentary thermal history, as the grains have experienced different thermal histories prior to deposition. Thereafter, the grains share a common thermal history. Thus, the extracted post-depositional histogram without inherited tracks may be used for thermal history calculation.

scholarly journals Age distribution of horizontal fission tracks

2021 ◽  
Author(s):  
Peter Klint Jensen ◽  
Kirsten Hansen
Keyword(s):  
Least Squares ◽  
Covariance Matrix ◽  
Thermal History ◽  
Prior Information ◽  
Age Distribution ◽  
Track Length ◽  
Fission Tracks ◽  
Apatite Crystals ◽  
Distribution Calculation ◽  
Thermal Histories

Abstract. Equations for the distribution of age versus length of partially annealed horizontal fission tracks in apatite is presented. Probabilistic least–squares inversion corrects natural track length histograms for observational biases considering the variance of data, modelization, and prior information. The corrected histogram is validated by its variance–covariance matrix. It is considered that horizontal track data can be with or without measurements of angles to the c–axis. In the last case, 3D–histograms are introduced as an alternative to histograms of c–axis projected track lengths. Thermal history modeling of samples is not necessary for track age distribution calculation. In an example the age equations are applied to apatites with pre–depositional (inherited) tracks, to extract the post–depositional track length histogram. Fission tracks generated before deposition in detrital apatite crystals are mixed with post–depositional tracks. This complicates the calculation of the post– sedimentary thermal history as the grains have experienced different thermal histories until deposition. Thereafter the grains share a common thermal history. The extracted post–depositional histogram without inherited tracks may be used for thermal history calculation.

Thermal annealing of fission tracks in fluorapatite, chlorapatite, manganoanapatite, and Durango apatite: experimental results

2003 ◽  
Vol 40 (7) ◽  
pp. 995-1007 ◽  
Author(s):  
Casey E Ravenhurst ◽  
Mary K Roden-Tice ◽  
Donald S Miller
Keyword(s):  
Thermal Annealing ◽  
Crystallographic Orientation ◽  
Nuclear Reactor ◽  
Crystallographic Direction ◽  
Track Length ◽  
Apatite Crystal ◽  
Etch Pits ◽  
Fission Tracks ◽  
History Analysis ◽  
Length Data

It is well known that the optically measured lengths of fission tracks in apatite crystals are a function of etching conditions, crystallographic orientation of the track, composition of the crystal, and the state of thermal annealing. In this study we standardize etching conditions and optimize track length measurability by etching until etch pits formed at the surface of each apatite crystal reached widths of about 0.74 μm. Etching times using 5M HNO3 at 21°C were 31 s for Otter Lake, Quebec, fluorapatite; 47 s for Durango, Mexico, apatite; 33 s for Portland, Connecticut, manganoanapatite; and 11 s for Bamle, Norway, chlorapatite. An etching experiment using two etchant strengths (5M and 1.6M HNO3) revealed that, despite significant differences in etch pit shape, fission-track length anisotropy with respect to crystallographic orientation of the tracks is not a chemical etching effect. A series of 227 constant-temperature annealing experiments were carried out on nuclear reactor induced tracks in oriented slices of the apatites. After etching, crystallographic orientations of tracks were measured along with their lengths. The 200–300 track lengths measured for each slice were ellipse-fitted to give the major (c crystallographic direction) and minor (a crystallographic direction) semi-axes used to calculate equivalent isotropic lengths. The equivalent isotropic length is more useful than mean length for thermal history analysis because the variation caused by anisotropy has been removed. Using normalized etching procedures and equivalent isotropic length data, we found that the fluorapatite anneals most readily, followed by Durango apatite, manganoanapatite, and lastly chlorapatite.

FISSION TRACK ANALYSIS: A NEW TOOL FOR THE EVALUATION OF THERMAL HISTORIES AND HYDROCARBON POTENTIAL

1983 ◽  
Vol 23 (1) ◽  
pp. 93 ◽  
Author(s):  
A. J. W. Gleadow ◽  
I. R. Duddy ◽  
J. F. Lovering
Keyword(s):  
Fission Track ◽  
Sedimentary Basins ◽  
Track Length ◽  
Fission Track Analysis ◽  
Fission Tracks ◽  
Annealing Zone ◽  
Oil Generation ◽  
Thermal Histories ◽  
Fission Track Ages ◽  
Track Analysis

Fission track dating is a new approach to the interpretation and quantitative modelling of thermal histories of sedimentary basins for hydrocarbon resource evaluation. This technique depends on the observation that annealing of fission tracks in minerals, like the generation and maturation of hydrocarbons, is a function of temperature and time. The temperature interval over which track annealing occurs in the mineral apatite, a common detrital mineral in sedimentary rocks, is virtually identical (60° to 125°C) with that required for the maximum generation of liquid hydrocarbons. Fission tracks in apatite separated from a rock sample thus contain a record of its heating in the oil generation window. The pattern of apatite fission track ages, together with detailed analyses of the distributions of track lengths, will yield information on thermal history unobtainable by other methods. The unique advantage of the fission track method is that it can give information not only on maximum palaeotemperatures, but also their variation through time.Fission tracks in detrital zircon and sphene are stable to higher temperatures (200° - 300°C) than in apatite enabling limits to be placed on maximum temperatures reached in sedimentary basins, as well as giving important information on sedimentary provenance.In the Otway and Gippsland Basins fission track ages and lengths determined on apatites, and ages determined on sphenes and zircons, have been used to reconstruct the thermal histories of different areas. Ages and track lengths of apatites from deep wells in the Otway Basin show the expected down hole decrease reaching zero apparent age where present well temperatures are about 125°C. The shape of the track length distribution is characteristic of the position of a sample within the track annealing zone and hence the oil generation window. Flaxmans-1 in the Otway Basin has an age profile indicating that present temperatures are at or very near the maximum experienced. In Eumeralla-1 sediments that lie above the present-day track annealing zone show clear evidence of track annealing in the past, indicating that temperatures have decreased. This is consistent with the relatively small amount of post-Early Cretaceous sedimentation observed in this well compared to Flaxmans-1.Fission track analysis thus has the potential of giving a new, quantitative perspective on the temperature history of rocks, which should have an important impact on techniques of petroleum exploration.

scholarly journals The Study of the Single Event Effect in AlGaN/GaN HEMT Based on a Cascode Structure

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 440
Author(s):  
Yanan Liang ◽  
Rui Chen ◽  
Jianwei Han ◽  
Xuan Wang ◽  
Qian Chen ◽  
...  
Keyword(s):  
Low Voltage ◽  
Ion Irradiation ◽  
Heavy Ion ◽  
Track Length ◽  
Single Event ◽  
Single Event Effects ◽  
Heavy Ion Irradiation ◽  
Enhancement Mode ◽  
Gan Hemt ◽  
Tcad Simulation

An attractive candidate for space and aeronautic applications is the high-power and miniaturizing electric propulsion technology device, the gallium nitride high electron mobility transistor (GaN HEMT), which is representative of wide bandgap power electronic devices. The cascode AlGaN/GaN HEMT is a common structure typically composed of a high-voltage depletion-mode AlGaN/GaN HEMT and low-voltage enhancement-mode silicon (Si) MOSFET connected by a cascode structure to realize its enhancement mode. It is well known that low-voltage Si MOSFET is insensitive to single event burnout (SEB). Therefore, this paper mainly focuses on the single event effects of the cascode AlGaN/GaN HEMT using technical computer-aided design (TCAD) simulation and heavy-ion experiments. The influences of heavy-ion energy, track length, and track position on the single event effects for the depletion-mode AlGaN/GaN HEMT were studied using TCAD simulation. The results showed that a leakage channel between the gate electrode and drain electrode in depletion-mode AlGaN/GaN HEMT was formed after heavy-ion striking. The enhancement of the ionization mechanism at the edge of the gate might be an important factor for the leakage channel. To further study the SEB effect in AlGaN/GaN HEMT, the heavy-ion test of a cascode AlGaN/GaN HEMT was carried out. SEB was observed in the heavy-ion irradiation experiment and the leakage channel was found between the gate and drain region in the depletion-mode AlGaN/GaN HEMT. The heavy-ion irradiation experimental results proved reasonable for the SEB simulation for AlGaN/GaN HEMT with a cascode structure.

Variation of the track length along the particle trajectory through CR-39 stack sheets

2005 ◽  
Vol 160 (1-2) ◽  
pp. 59-65 ◽  
Author(s):  
M. F. Zaki ◽  
Tarek M. Hegazy ◽  
U. Seddik ◽  
A. Ahmed Morsy
Keyword(s):  
Particle Trajectory ◽  
Track Length
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