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Sample records for apatite fission track

  1. The relationship between fission track length and track density in apatite

    International Nuclear Information System (INIS)

    Laslett, G.M.; Gleadow, A.J.W.; Duddy, I.R.

    1984-01-01

    Fission track dating is based upon an age equation derived from a random line segment model for fission tracks. This equation contains the implicit assumption of a proportional relationship between the true mean length of fission tracks and their track density in an isotropic medium. Previous experimental investigation of this relationship for both spontaneous and induced tracks in apatite during progressive annealment model in an obvious fashion. Corrected equations relating track length and density for apatite, an anisotropic mineral, show that the proportionality in this case is between track density and a length factor which is a generalization of the mean track length combining the actual length and crystallographic orientation of the track. This relationship has been experimentally confirmed for induced tracks in Durango apatite, taking into account bias in sampling of the track lengths, and the effect of the bulk etching velocity. (author)

  2. Detrital zircon and apatite fission track data in the Liaoxi basins ...

    Indian Academy of Sciences (India)

    AFT and ZFT ages were performed at Fission. Track Laboratory of Changsha Institute of Geo- tectonics, Chinese Academy of Sciences and Fis- sion Track Laboratory of Institute of Geology,. Chinese Earthquake Administration, respectively. Glass slides with apatites mounted in epoxy resin were etched using 1% HNO3 at ...

  3. Apatite fission track dating and thermal history of Qing-He region in Altay Mountains

    International Nuclear Information System (INIS)

    Bao Zengkuan; Chinese Academy of Sciences, Beijing; Yuan Wanming; Dong Jinquan; Gao Shaokai

    2005-01-01

    Fission track ages (FTA) and track lengths of apatite from Qing-He diorite intrusion in Altay Mountains are measured. Apatite fission track ages of three diorite samples is range from (78±5) Ma to (95 ± 5) Ma, and the lengths of horizontal confined spontaneous fission tracks are (13.2 ± 1.2)-(13.5 ±1.3) μm. The distribution of the track length is narrow and symmetrical with a mean length of approximately 13.3 μm and a standard deviation of around 0.1 μm. The inverse modeling results show that thermal history of this region has four stages, two rapid uplift of this region still existed magmatic intrusion and tectonic movements in Yanshanian. (authors)

  4. Detrital zircon and apatite fission track data in the Liaoxi basins ...

    Indian Academy of Sciences (India)

    vation events in the northern margin of the North. China Craton (figure 1a). In this paper, detrital zircon and apatite fission track (AFT and ZFT) ages of the sedimentary rocks from the Liaoxi basins are presented. The purposes of this study are: • to study the geothermal status of the basins to understand lithosphere evolution;.

  5. Apatite fission-track analysis of the tectonic effects of the Arabia-Eurasia collision

    Science.gov (United States)

    Albino, I.; Cavazza, W.; Zattin, M.; Okay, A. I.; Adamia, S.; Sadradze, N.

    2012-04-01

    The Oligo-Miocene collision between Arabia and Eurasia led to the development of (i) the Bitlis-Zagros orogenic belt, (ii) the North and East Anatolian fault systems, (iii) the structural inversion of the Caucasian basins, and (iv) widespread deformation in the Turkish-Armenian-Iranian plateau. Despite the importance of the event, the exact age of the collision is poorly constrained. The integration of new apatite fission-track (AFT) data from the eastern Pontides, the Lesser Caucasus (Adjara-Trialeti zone), and the eastern part of the Anatolian plateau with preexisting data from the Bitlis suture has provided insights on the syn-and post-collisional evolution not only of eastern Anatolia but also of the entire Eastern Mediterranean area. The AFT samples have a wide spatial distribution and include different types of rocks: Paleogene sandstones and magmatic rocks with Cretaceous-to-Eocene intrusion ages. Despite the disparate lithologies and large distance, apatite fission-track ages from the easternmost Pontides, the Georgian Lesser Caucasus, the eastern Anatolian Plateau, and the Bitlis collision zone show a distinct geographic pattern. Exhumation along the Black Sea coast occurred in the Middle Miocene, mirroring the age of collision between the Eurasian and Arabian plates along the 2,400-km long Bitlis-Zagros suture zone some 200 km to the south. Exhumation in the Anatolian Plateau occurred in the Paleogene (with a cluster of ages in the Middle-Late Eocene), coevally with the development of the Izmir-Ankara-Erzincan suture. Successive development of the Anatolian Plateau did not exhume a new partial annealing zone and thus is not recorded by the apatite fission tracks.

  6. Quantitative Identification of the Annealing Degree of Apatite Fission Tracks Using Terahertz Time Domain Spectroscopy (THz-TDS).

    Science.gov (United States)

    Wu, Hang; Wu, Shixiang; Qiu, Nansheng; Chang, Jian; Bao, Rima; Zhang, Xin; Liu, Nian; Liu, Shuai

    2018-01-01

    Apatite fission-track (AFT) analysis, a widely used low-temperature thermochronology method, can provide details of the hydrocarbon generation history of source rocks for use in hydrocarbon exploration. The AFT method is based on the annealing behavior of fission tracks generated by 238 U fission in apatite particles during geological history. Due to the cumbersome experimental steps and high expense, it is imperative to find an efficient and inexpensive technique to determinate the annealing degree of AFT. In this study, on the basis of the ellipsoid configuration of tracks, the track volume fraction model (TVFM) is established and the fission-track volume index is proposed. Furthermore, terahertz time domain spectroscopy (THz-TDS) is used for the first time to identify the variation of the AFT annealing degree of Durango apatite particles heated at 20, 275, 300, 325, 450, and 500 ℃ for 10 h. The THz absorbance of the sample increases with the degree of annealing. In addition, the THz absorption index is exponentially related to annealing temperature and can be used to characterize the fission-track volume index. Terahertz time domain spectroscopy can be an ancillary technique for AFT thermochronological research. More work is urgently needed to extrapolate experimental data to geological conditions.

  7. Rate of erosion and exhumation of crystalline rocks in the Hunza Karakoram defined by apatite fission track analysis

    Czech Academy of Sciences Publication Activity Database

    Kořínková, Dagmar; Svojtka, Martin; Kalvoda, J.

    2014-01-01

    Roč. 11, č. 3 (2014), s. 235-253 ISSN 1214-9705 Institutional research plan: CEZ:AV0Z30130516 Institutional support: RVO:67985831 Keywords : apatite fission-track analysis * erosion * exhumation of rocks * Karakoram Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.389, year: 2014

  8. Post late Paleozoic tectonism in the Southern Catalan Coastal Ranges (NE Spain), assessed by apatite fission tracks analysis

    NARCIS (Netherlands)

    Juez-Larré, J.; Andriessen, P.A.M.

    2002-01-01

    We report the first apatite fission-track thermochronologic data for 17 samples from the southern Catalan Coastal Ranges of NE Spain. Thermal histories of Carboniferous metasediments, Late Hercynian intrusions and Lower-Triassic Buntsandstein sediments from three tectonics blocks, Miramar, Prades

  9. Possible secondary apatite fission track age standard from altered volcanic ash beds in the middle Jurassic Carmel Formation, Southwestern Utah

    Science.gov (United States)

    Kowallis, B.J.; Christiansen, E.H.; Everett, B.H.; Crowley, K.D.; Naeser, C.W.; Miller, D.S.; Deino, A.L.

    1993-01-01

    Secondary age standards are valuable in intra- and interlaboratory calibration. At present very few such standards are available for fission track dating that is older than Tertiary. Several altered volcanic ash beds occur in the Middle Jurassic Carmel Formation in southwestern Utah. The formation was deposited in a shallow marine/sabhka environment. Near Gunlock, Utah, eight ash beds have been identified. Sanidines from one of the ash beds (GUN-F) give a single-crystal laser-probe 40Ar/39Ar age of 166.3??0.8 Ma (2??). Apatite and zircon fission track ages range from 152-185 Ma with typically 15-20 Ma errors (2??). Track densities in zircons are high and most grains are not countable. Apatites are fairly common in most of the ash beds and have reasonable track densities ranging between 1.2-1.5 ?? 106 tracks/cm2. Track length distributions in apatites are unimodal, have standard deviations sieving. GUN-F shows evidence of some reworking and detriaal contamination based on older single grain 40Ar/39Ar analyses and some rounding of grains, but the apatite population appears to be largely uncontaminated. At present BJK has approximately 12 of apatite separate from GUN-F. ?? 1993.

  10. Apatite fission track analysis on tectonic activities and paleotopography in southern Altai region, Xinjiang, China

    International Nuclear Information System (INIS)

    Zhao Wenju; Yuan Wanming; Liu Haotao; Song Gao

    2013-01-01

    This work engages apatite fission track evidences on thermotectonic history, rock uplift rate, denudation extent southeastern Altai region. Fission track ages of 14 samples range from (59.4±5.8) Ma to (109.7±8.1) Ma and the length is between (12.0±2.5) μm and (13.7±1.5) μm. Thermal modeling reveals that the samples have a three-stage of uplift-cooling history. The first stage is in an overall initial uplift before 108 Ma, the second stage from 108 Ma to 28 Ma experiences a slow cooling phase, and the last stage through a rapid-cooling process since 28 Ma with a cooling rate 1.25 1.61 ℃/Ma and denudation amount 1.17-1.50 km, the fast exhumation period in the area. The sample ages could be divided into 4 age groups, reflecting multiple tectonic events with different uplift rates. The paleotopography altitude changes from 3895 m to 821 m, 2250 m to 762 m etc., and the amplitude of changes reaches to 3300-1400 m since 90 Ma. The phenomenon of Alpine turning to valley and valley uplifting is visible in the studied area, indicating various stages of paleotopography. Based on inversion of ancient landforms and equilibrium correction, the equilibrium rebound would play an important role in the rock uplift during the Altai post-orogenic period. (authors)

  11. Thermal history of the Tiereketi batholith in Altay Mountains, northern Xinjiang: evidence from apatite fission track analysis

    International Nuclear Information System (INIS)

    Yuan Wanming; Dong Jinquan; Tang Yunhui; Bao Zengkuan

    2003-01-01

    The result of fission track analysis of 4 apatite samples collected from Tiereketi granite-batholith in Altay Mountains, northern Xinjiang, shows a three stages of thermal history. First, before 120 Ma the temperature was 105-130∼90-120; second, the temperature quite ranged from 90-120 to 20-65 during 60-120 Ma and third, it was 20-65∼12-18 since 60 Ma. The 60~90 Ma was a rapid cooling and uplift stage, with cooling rate of 2.5-3.23/Ma and uplift rate of 3.3-107.7 m/Ma. The rapid uplift during the 60-120 Ma and the apatite fission track age of 80.4-91.9 Ma indicate that there was a intracontinental press-orogeny in about 60-120 Ma, which is a new understand. (authors)

  12. Apatite fission track implications for timing of hydrothermal fluid flow in Tertiary volcanics of the Bohemian Massif

    Czech Academy of Sciences Publication Activity Database

    Filip, Jiří; Ulrych, Jaromír; Adamovič, Jiří; Balogh, K.

    2007-01-01

    Roč. 52, 3-4 (2007), s. 211-220 ISSN 0449-2560 R&D Projects: GA AV ČR IAA3013403 Grant - others:OTKA(HU) T060965; OTKA(HU) M41434 Institutional research plan: CEZ:AV0Z30130516 Keywords : Bohemian Massif * fission track s * apatite * K-Ar dating * volcanic rocks * thermal events * stress field Subject RIV: DB - Geology ; Mineralogy

  13. Reconstructing Post-Carboniferous History of the Krkonoše Piedmont Basin Using Detrital Apatite Fission-Track Data

    Czech Academy of Sciences Publication Activity Database

    Martínek, K.; Svojtka, Martin; Filip, Jiří

    2006-01-01

    Roč. 20, - (2006), s. 91-92 ISSN 1210-9606. [Meeting of the Central European Tectonic Studies Group /4./. Zakopane, 19.04.2006-22.04.2006] Institutional research plan: CEZ:AV0Z30130516 Keywords : fission-track * Krkonoše * apatite Subject RIV: DB - Geology ; Mineralogy http://geolines.gli.cas.cz/fileadmin/volumes/volume20/G20-091b.pdf

  14. Apatite fission track data from central Anatolian granitoids (Turkey): Constraints on Neo-Tethyan closure

    Science.gov (United States)

    Boztuǧ, Durmuş; Jonckheere, Raymond C.

    2007-06-01

    Apatite fission track age versus elevation profiles and temperature-time-path modeling indicate an early to middle Paleocene (57-62 Ma) rapid exhumation of the Middle to Late Cretaceous granitoids in central Anatolia and an Oligocene (28-30 Ma) rapid exhumation of the Eocene Kösedaǧ batholith in the NE Sivas region, part of eastern central Pontides. The early to middle Paleocene rapid exhumation is thought to result from a regional compressional regime following the collision of the Eurasian Plate and the Tauride-Anatolide Platform at the closure of the Izmir-Ankara-Erzincan branch of the northern Neo-Tethys. The Oligocene accelerated exhumation of the Kösedaǧ batholith is contemporaneous with the Oligo-Miocene closure of the southern Neo-Tethys which juxtaposed the amalgamated Eurasian and Tauride-Anatolide Platform and the African-Arabian Plate along the Bitlis-Zagros suture in southeast Anatolia. The compressional regime due to this collision affected a large area between the Greater Caucasus in the north and northern African-Arabian Plate in the south.

  15. Apatite fission track dating of the Northern Western Shield, Western Australia

    International Nuclear Information System (INIS)

    Weber, U.D.; Kohn, B.P.; Gleadow, A.J.W.

    1999-01-01

    Full text:The investigation of the thermotectonic evolution of the northern part of the Precambrian Western Shield of Western Australia using apatite fission track (AFT) thermochronology is the main focus of this study. The study area encompasses Precambrian rocks of the Pilbara Craton and the northern part of the Yilgarn Craton including the Narryer Gneiss Complex. AFT data, mostly from the Archaean cratons reveal cooling ages ranging between 260±8 Ma and 400±20 Ma. Mean confined horizontal track lengths fall between ∼12 and 13 μm with standard deviations ranging from 1.1-2.2 μm. Forward modelling of time-temperature history paths for representative samples reveals a period of regional cooling of at least ∼50 deg C in the late Palaeozoic. Most paths also show a second period of cooling of 25 deg C from temperatures of ∼80-85 deg C. This later cooling episode occurred in the Mesozoic but its timing is less well constrained. Assuming that the average present day geothermal gradient of ∼18±2 deg C per km - 1 was prevalent since the late Palaeozoic, then the minimum of ∼75 deg C of cooling predicted by the fission track modelling suggests overall denudation of at least ∼ 3.7-4.6 km of section since that time. Phanerozoic basins (Perth, Carnarvon and Canning) adjacent to the north and west of the northern Western Shield mostly continue offshore and form complex structures containing up to ∼ 15 km of predominantly clastic sediments of early Ordovician to late Cretaceous age. The basins are likely to have been depocentres for much of the detritus derived from the denudation inferred from the cooling recorded by the AFT. Possible causative events which could be linked to the observed late Palaeozoic cooling are tectonism related to the collision of Gondwanaland with Laurussia in Carboniferous time forming the supercontinent Pangea or a possible far-field effect related to the Alice Springs Orogeny. Further low temperature thermochronological studies

  16. Thermal and exhumation history of Sakhalin Island (Russia) constrained by apatite U-Pb and fission track thermochronology

    Science.gov (United States)

    Glorie, Stijn; Alexandrov, Igor; Nixon, Angus; Jepson, Gilby; Gillespie, Jack; Jahn, Bor-Ming

    2017-08-01

    Sakhalin Island represents a key locality to study the tectonic evolution of the western Pacific. The island is located at the Amur-Okhotsk plate margin and records a complex thermotectonic history. Apatite double dating (U-Pb and fission track) and thermal history modelling were applied to three late Eocene granitoid massifs within central and southern Sakhalin: the Aniva, Okhotsk and Langeri complexes. Apatite U-Pb results yield consistent late Eocene (∼40-37 Ma) ages, suggesting rapid post-magmatic cooling. Apatite fission track results reveal bimodal age distributions with late Eocene - early Oligocene (∼38-33 Ma) and early Miocene (∼20-17 Ma) age populations that can be correlated with variations in Uranium and Chlorine concentrations. Thermal history modelling translates the AFT age bimodality into two-phase cooling histories. The timing of the early cooling phase (∼38-33 Ma) corresponds with the apatite U-Pb ages, indicating rapid cooling to at least ∼100 °C during the late Oligocene. The second cooling phase at ∼20-17 Ma cooled the samples to near-surface temperatures. Both cooling phases correspond with regional unconformities and subsequent accelerations in sedimentation rate, suggesting that cooling was a response to rapid exhumation. In addition, our data suggests that the studied terranes record differential exhumation with respect to the structural architecture. The Miocene exhumation pulse is coeval with the timing of transpressional fault displacement and the subsequent opening of the Kuril Basin.

  17. Fission track ages on apatite of Bergell rocks from central Alps and Bergell boulders in Oligocene sediments

    International Nuclear Information System (INIS)

    Wagner, G.A.; Miller, D.S.

    1979-01-01

    Previous radiometric dating studies indicated that the Bergell region, in contrast to other regions of the Central Alps, experienced an early, rapid uplift, but with decreasing rate. Furthermore, there is also a geological record of the early uplift history of the Bergell granite by the existence of boulders which were derived from this granite and which occur in the Late Oligocene sediments of the Po plain. In this work the uplift history of the Bergell is studied in more detail by fission track dating of additional apatites from the Bergell region. Secondly, by determining apatite fission track ages the granitic boulders of the Po plain can be re-assigned to their original vertical position within the Bergell intrusive before erosion removed them in Late Oligocene time. A rather conservative estimate replaces them 6 km above the present morphology of the Bergell massif. Thus, the thickness of the Bergell granite must have been at least 8 km. Generally, fission track studies on boulders may become an important tool to study the vertical extent of mountain chains during the geological past. (Auth.)

  18. Relation between denudation history and sediment supply from apatite fission track thermochronology in the northeast Brazilian Margin

    Science.gov (United States)

    Jelinek, Andrea; Chemale, Farid; Bueno, Gilmar

    2014-05-01

    The aim of this study is to provide a quantitative overview of Mesozoic-Cenozoic morphotectonic evolution and sediment supply to the northeast Brazilian margin. Landscape evolution and denudation histories for the northeastern Brazilian continental margin (Sergipe, Alagoas, Bahia, and Espírito Santo states) were detailed by apatite fission track thermochronology and thermal-history modeling and related with the sedimentological record of the offshore basins of the passive margin for a comparison with their denudational history. Approximately one hundred basement samples were analyzed from the coast to the inland of the Brazilian margin. The apparent fission track ages vary from 360 to 61 Ma and confined fission track lengths vary between 10 and 14.6 µm, indicating that not all of the samples recorded the same cooling events. The results of apatite fission track ages indicate that the area has been eroded regionally since the Mesozoic (Sergipe-Alagoas basins. Samples from the Conquista and Borborema Plateaus, and Mantiqueira Range record a Cretaceous-Paleogene onset of exhumation. This timing is consistent with the offshore sedimentary record, wherein a large clastic wedge started forming in the northeastern Sergipe-Alagoas basin, which suggests Sergipe-Alagoas basin records drainage reorganization and extension of the São Francisco River catchment. Interestingly, the Camamu basin, adjacent to the section of the margin does not record syn/post-rift exhumation, does contain a 6-km thick sedimentary succession, which should thus have been derived from more distal sources. The Neogene final denudation is observed throughout the study area and show conspicuous recent exhumation. The post-rift (<40 Ma) offshore sedimentation rates are generally lower than during preceding phases. This final sedimentary succession is thinner in all basins, consistent with limited onshore erosion during this time.

  19. Multiple cooling episodes in the Central Tarim (Northwest China) revealed by apatite fission track analysis and vitrinite reflectance data

    Science.gov (United States)

    Chang, Jian; Qiu, Nansheng; Song, Xinying; Li, Huili

    2016-06-01

    Apatite fission track and vitrinite reflectance are integrated for the first time to study the cooling history in the Central Tarim, northwest China. The paleo-temperature profiles from vitrinite reflectance data of the Z1 and Z11 wells showed a linear relationship with depth, suggesting an approximately 24.8 °C/km paleo-geothermal gradient and 2700-3900 m of erosion during the Early Mesozoic. The measured apatite fission track ages from well Z2 in the Central Tarim range from 39 to 159 Ma and effectively record the Meso-Cenozoic cooling events that occurred in Central Tarim. Moreover, two cooling events at 190-140 Ma in the Early Jurassic-Early Cretaceous and 80-45 Ma in the Late Cretaceous-Paleocene revealed by measured AFT data and thermal modeling results are related to the collisions of the Qiangtang-Lhasa terranes and the Greater India Plate with the southern margin of the Eurasian Plate, respectively. This study provides new insights into the tectonic evolution of the Tarim Basin (and more broadly Central Asia) and for hydrocarbon generation and exploration in the Central Tarim.

  20. Apatite fission track thermochronology and south east Australian landscape evolution: can exaggerated denudation rates be reconciled?

    International Nuclear Information System (INIS)

    Roach, I.C.

    1999-01-01

    Full text: Apatite fission track thermo chronology (AFTT) is a double-edged sword that can be used to both identify the absolute timing of major landscape-forming events and to estimate the amount of denudation that has occurred in a landscape. This powerful tool has added much to the debate of eastern Australian landscape evolution, particularly the origin and evolution of the Eastern Highlands. However, many authors can not reconcile estimates of the amount of denudation derived from AFTT with their own knowledge of the apparent stability of eastern Australian landscapes. Thus they regard the calculated denudation rates as being exaggerated. This difference in opinion comes about principally from the insistence of applying an upper crustal palaeogeotherm of 25-30 deg C km blanket-wise to all AFTT results. Recent thematic papers in the Australian Journal of Earth Sciences (Volume 46/2) related to eastern Australian landscape evolution highlight the differences of opinion. Kohn et al. (1999), in a paper relating to an AFTT study of the Kosciuszko massif, concluded that the landscape was controlled by two periods of accelerated denudation, one in the Late Permian-Early Triassic and the other in the mid-Cretaceous. They calculated that 2-2.5 km of material had been denuded from the massif since the mid-Cretaceous. Hill (1999) expressed an opposite viewpoint, describing residual landscapes of Mesozoic age existing in the same massif, indicating a much reduced denudation rate. van der Beek et al. (1999) discussed the need for more realistic models that compensate for the 'extreme temporal and spatial variability in denudation rates' possible within their own model. Particularly, they concluded that Late Mesozoic-Early Tertiary palaeogeotherms must have been higher than present. This knowledge is crucial to understanding Eastern Australian landscape evolution. A suite of mantle and lower crustal xenoliths has yielded a new palaeogeotherm for the Eocene-Oligocene Monaro

  1. The thermal history of the Miocene Ibar Basin (Southern Serbia: new constraints from apatite and zircon fission track and vitrinite reflectance data

    Directory of Open Access Journals (Sweden)

    Andrić Nevena

    2015-02-01

    Full Text Available The Ibar Basin was formed during Miocene large scale extension in the NE Dinaride segment of the Alpine- Carpathian-Dinaride system. The Miocene extension led to exhumation of deep seated core-complexes (e.g. Studenica and Kopaonik core-complex as well as to the formation of extensional basins in the hanging wall (Ibar Basin. Sediments of the Ibar Basin were studied by apatite and zircon fission track and vitrinite reflectance in order to define thermal events during basin evolution. Vitrinite reflectance (VR data (0.63-0.90 %Rr indicate a bituminous stage for the organic matter that experienced maximal temperatures of around 120-130 °C. Zircon fission track (ZFT ages indicate provenance ages. The apatite fission track (AFT single grain ages (45-6.7 Ma and bimodal track lengths distribution indicate partial annealing of the detrital apatites. Both vitrinite reflectance and apatite fission track data of the studied sediments imply post-depositional thermal overprint in the Ibar Basin. Thermal history models of the detritial apatites reveal a heating episode prior to cooling that began at around 10 Ma. The heating episode started around 17 Ma and lasted 10-8 Ma reaching the maximum temperatures between 100-130 °C. We correlate this event with the domal uplift of the Studenica and Kopaonik cores where heat was transferred from the rising warm footwall to the adjacent colder hanging wall. The cooling episode is related to basin inversion and erosion. The apatite fission track data indicate local thermal perturbations, detected in the SE part of the Ibar basin (Piskanja deposit with the time frame ~7.1 Ma, which may correspond to the youngest volcanic phase in the region.

  2. Mesozoic and Cenozoic uplift and exhumation of the Bogda Mountain, NW China: Evidence from apatite fission track analysis

    Directory of Open Access Journals (Sweden)

    Wenhao Tang

    2015-07-01

    Full Text Available Apatite fission track (AFT analysis on samples collected from a Paleozoic series is used to constrain the cooling history of the Bogda Mountain, northwest China. AFT ages range from 136.2 to 85.6 Ma and are younger than rock depositional ages and the mean confined track lengths (11.0–13.2 μm mostly showing unimodal distribution are shorten, indicating significant track-annealing. Thermal histories modeling based on the distribution of fission-track lengths combined with the regional geological data show that two rapid cooling phases occurred in the latest Jurassic–early Cretaceous and the Oligocene–Miocene. Those new data together with previous published data show that the AFT ages become younger from the southwest to northeast in the western Bogda Mountain and its adjacent areas. The fission-track ages of the southwest area are relatively older (>100 Ma, recording the earlier rapid uplift phase during the late Jurassic–Cretaceous, while the ages in the north piedmont of the Bogda Mountain (namely the northeast part are younger (<60 Ma, mainly reflecting the later rapid uplift phase in the Oligocene–Miocene. The trend of younger AFT ages towards the northeast might be explained by post-Cretaceous large-scale crustal tilting towards the southwest. In the thrust fault-dominated northern limbs of the Bogda Mountain, AFT ages reveal a discontinuous pattern with age-jumps across the major fault zones, showing a possible strata tilting across each thrust faults due to the thrust ramps during the Cenozoic. The two rapid uplift stages might be related to the accretion and collision in the southern margin of the Asian continent during the late Jurassic and late Cenozoic, respectively.

  3. Multiphase cooling and exhumation of the Krkonoše Piedmont Basin during Mesozoic - Cenozoic basin inversion based on apatite fission track analysis

    Czech Academy of Sciences Publication Activity Database

    Martínek, K.; Svojtka, Martin; Filip, Jiří

    2008-01-01

    Roč. 34, 4/6 (2008), s. 1353003-1353003 ISSN 0161-6951. [International Geological Congress /33./. 06.08.2008-14.08.2008, Oslo ] R&D Projects: GA AV ČR KJB3111305 Institutional research plan: CEZ:AV0Z30130516 Keywords : fission track * apatite * Krkonoše Piedmont basin Subject RIV: DB - Geology ; Mineralogy

  4. Phanerozoic polycyclic evolution of the southwestern Angola margin: New insights for apatite fission track and (U-Th)/He methodologies

    Science.gov (United States)

    Venancio da Silva, Bruno; Hackspacher, Peter; Carina Siqueira Ribeiro, Marli; Glasmacher, Ulrich Anton

    2016-04-01

    The low-temperature thermochronology has been an important tool to quantify geological process in passive continental margins. In this context, the Angolan margin shows evidence of a polycyclic post-rift evolution marked by different events of uplift, basin inversion and changes in sedimentation rates to the marginal basins, which have controlled the salt tectonics and the hydrocarbon deposits (1,2,3,4). To understand the post break-up evolution of the southwestern Angola margin, it were collected outcrop samples for apatite fission track (AFT) and (U-Th)/He analysis ranging in elevation from 79 m to 1675 m from the coast toward the interior plateau in a profile between Namibe and Lubango cities. The area lies on the edge of Central and Southern Atlantic segments a few kilometers northward the Walvis ridge and encompasses the Archean and Proterozoic basement rocks of the Congo craton. The AFT ages ranging from 120.6 ± 8.9 Ma to 328.8 ± 28.5 Ma and they show a trend of increasing age toward the Great Escarpment with some exceptions. The partial mean track lengths (MTLs) vary between 11.77 ± 1.82 μm to 12.34 ± 1.13 μm with unimodal track length distributions (TDLs). The partial (U-Th)/He ages ranging from 104.85 ± 3.15 Ma to 146.95 ± 4.41 Ma and show the same trend of increasing ages landward, little younger than the AFT ages, which could be interpreted as a fast exhumation episode in Late Jurassic - Early Cretaceous times. The thermal histories modelling has been constrained with the kinetic parameters Dpar (5) and c-axis angle (6) by the software Hefty (7). Both AFT and (U-Th)/He thermal histories modelling indicate three episodes of denudation/uplift driven cooling: (a) from Late Jurassic to Early Cretaceous, (b) a smallest one in the Late Cretaceous and (c) from Oligocene-Miocene to recent, which are compatible with geophysical data of the offshore Namibe basin that estimate the greater thickness of sediments formed in the first and third episodes

  5. Timing of Exhumation of the Mesozoic Blue Nile Rift, Ethiopia: A New Study from Apatite Fission Track Thermochronology

    Science.gov (United States)

    Gani, N. D.; Bowden, S. M.

    2017-12-01

    At present, tectonic features of Ethiopia are dominated by the 2.5 km high Ethiopian Plateau, and the NE-SW striking continental rift, the East African Rift System (EARS) that dissected the plateau into the northwest and southeast plateaus. The stress direction of the EARS is nearly perpendicular to the stress direction of the Mesozoic rifts of the Central African Rift System (CARS), located mostly in Sudan, Ethiopia and Kenya. During the Gondwana splitting in Mesozoic, active lithospheric extension within the CARS resulted in several NW-SE striking continental rifts including the Blue Nile, Muglad, Melut and Anza that are well documented in Sudan and Kenya, from a combination of geophysical and drill core analysis and field investigations. However, the timing and evolution of the poorly documented Blue Nile Rift in Ethiopia, now hidden in the subsurface of the Ethiopian Plateau and the EARS, is largely unknown. This study investigates, for the first time, the timing of tectono-thermal evolution of the Blue Nile Rift from cooling ages deduced from apatite fission track (AFT) thermochronology to understand the rift flank exhumation. Here, we report the AFT results from basement samples collected in a vertical transect from the Ethiopian Plateau. The fission track ages of the samples show a general trend of increasing cooling ages with elevations. The time-temperature simulations of the fission track ages illustrate that the cooling started at least 80 Ma ago with a significant amount of rapid cooling between 80 and 70 Ma, followed by a slow cooling after 70 Ma and then another accelerated cooling starting around 10 Ma. The Cretaceous rapid cooling event likely related to the flank uplift of the Blue Nile Rift and associated faulting, during which much of the exhumation occurred. Today, the Blue Nile Rift is buried under the thick cover of Mesozoic sedimentary rocks and Cenozoic volcanics. The late Neogene rapid cooling agrees well with our previous thermal model

  6. The Thermal Evolution of the Southeast Baffin Island Continental Margin: An Integrated Apatite Fission Track and Apatite (U-Th)/He Study

    Science.gov (United States)

    Jess, S.; Stephenson, R.; Brown, R. W.

    2017-12-01

    The elevated continental margins of the North Atlantic continue to be a focus of considerable geological and geomorphological debate, as the timing of major tectonic events and the age of topographic relief remain controversial. The West Greenland margin, on the eastern flank of Baffin Bay, is believed by some authors to have experienced tectonic rejuvenation and uplift during the Neogene. However, the opposing flank, Baffin Island, is considered to have experienced a protracted erosional regime with little tectonic activity since the Cretaceous. This work examines the thermal evolution of the Cumberland Peninsula, SE Baffin Island, using published apatite fission track (AFT) data with the addition of 103 apatite (U-Th)/He (AHe) ages. This expansion of available thermochronological data introduces a higher resolution of thermal modelling, whilst the application of the newly developed `Broken Crystals' technique provides a greater number of thermal constraints for an area dominated by AHe age dispersion. Results of joint thermal modelling of the AFT and AHe data exhibit two significant periods of cooling across the Cumberland Peninsula: Devonian/Carboniferous to the Triassic and Late Cretaceous to present. The earliest phase of cooling is interpreted as the result of major fluvial systems present throughout the Paleozoic that flowed across the Canadian Shield to basins in the north and south. The later stage of cooling is believed to result from rift controlled fluvial systems that flowed into Baffin Bay during the Mesozoic and Cenozoic during the early stages and culmination of rifting along the Labrador-Baffin margins. Glaciation in the Late Cenozoic has likely overprinted these later river systems creating a complex fjordal distribution that has shaped the modern elevated topography. This work demonstrates how surface processes, and not tectonism, can explain the formation of elevated continental margins and that recent methodological developments in the field of

  7. Tectonic setting and uplift analysis of the Pangani rift basin in northern Tanzania using apatite fission track thermochronology

    International Nuclear Information System (INIS)

    Mbede, E.I.

    2001-01-01

    Thirty four new Apatite Fission Track (AFT) ages and 32 track length distributions from samples of basement rocks flanking the Pangani rift, East African Rift System (EARS) are presented, in an attempt to elucidate the uplift and erosion of the rift flanks. The ages fall in the range of 207±15 to 48±4 Ma, spanning from Early Jurassic to Early Tertiary. These ages are much younger than the last thermal event in the Mozambique belt that form the basement complex and are interpreted to represent the most recent tectonic events. Track length (TL) distributions suggest that uplift and erosion of the rift flanks are related to three different tectonic events, which are also recorded by the sedimentary units within the adjacent coastal basins. These included the Triassic/Early Jurassic, Late Cretaceous and Early Tertiary tectonic events. Erosion and isostatic rebound have modified the tectonically induced topographic patterns and the highly elevated plateaus flanking the Pangani rift represent an erosional surface referred to as the 'Gondwana surface' of eastern and central Africa. T he present AFT data suggest that initial exhumation of the 'Gondwana surface' from temperatures above 383.15 K to temperatures less than 333.15 K, in this area, took place during Early Jurassic times, but the final sub-aerial exposure of the surface did not take place until Early Tertiary. (author)

  8. Mesozoic-Cenozoic tectonic evolution and its relation to sandstone-type uranium mineralization in northern Tarim area--Evidence from apatite fission track

    International Nuclear Information System (INIS)

    Liu Hongxu; Dong Wenming; Liu Zhangyue; Chen Xiaolin

    2009-01-01

    The apatite fission track dating and inversion result of geological thermal history of four rock specimens from Sawafuqi area and Talike area in northern Tarim Basin show that two areas uplifted at different ages. The apatite fission track ages of Sawafuqi range from 3.5 to 3.9 Ma, while the ages of Talike range from 53 to 59 Ma. The thermal history recorded by rock samples reveals that there are at least three prominent cooling phases since Late Cretaceous epoch. Detailed study was made on the division of uplifting stages during Mesozoic and Cenozoic tectonic evolution with the existing data in northern Tarim area. And new ideas on tectonic evolution and sandstone-type uranium mineralization have been put forward by combining with the sandstone-type uranium mineralization ages in this area.(authors)

  9. Multistage tectonic block movements in the Catalan Coastal Ranges (NE Spain) since late Paleozoic assed by apatite and zircon fission-track, and (U-Th)/He. 27th assembly of the European Geophysical Society

    NARCIS (Netherlands)

    Juez-Larré, J.; Andriessen, P.A.M.

    2002-01-01

    Multistage tectonic block movements in the Catalan Coastal Ranges (NE Spain) since late Paleozoic assed by apatite and zircon fission-track, and (U-Th)/He. 27th assembly of the European Geophysical Society

  10. Apatite fission track analysis for revealing tectonic events of the Bayinguole area in the west section of Eastern Kunlun Mountains, northern Qinghai-Tibet Plateau

    International Nuclear Information System (INIS)

    Chen Xiaoning; Yuan Wanming; Hao Nana; Duan Hongwei; Feng Yunlei; Zhang Aikui

    2014-01-01

    Background: Qimantage is an important tectonic metallogenic belt in western part of East Kunlun Mountain. It has experienced complex geological evolution, and significant mineralization. However, because of the plateau climate and inaccessibility, fewer research works have been done on this area, especially after Indo-sinian epoch. Purpose: Our work is to research tectonic activity, thermal history and uplifting around Bayinguole river in Qimantage belt. Methods: The apatite fission-track method was applied to research the tectonic setting, simulate the thermal history and calculate the uplift size and uplift speed. Results: A series of apatite fission track ages from granitoid samples in Bayinguole area of Eastern Kunlun Mountain were obtained, ranging from 120 Ma to 47 Ma that might be divided into three groups': 120-100 Ma, 67 Ma and 54-47 Ma. These ages reflected tectonic events in this area very well. Conclusions: The 120-100 Ma and 67 Ma ages present collision-convergences of Gangdese terrane and Himalayan terrane with their north-side terranes in Early Cretaceous and Late Cretaceous respectively. The ages of 54-47 Ma reflect post-orogenic stretching events in Eocene. Three stages of thermal evolution history are revealed by apatite fission track modeling in this area. Stage one 180-140 Ma is in the bottom temperature of apatite fission track anneal zone. Stage two 140-13 Ma records slow cooling. The last stage after 13 Ma records rapid cooling with temperature dropped 50℃. The uplifting ranges for these three stages are 1.0 km, 0.6 km and 1.4 km, respectively. The cumulative amount of uplift is about 3.0 km. The formula calculations for the 3 samples have their rock uplifts of 3623 m, 3317 m and 3769 m, respectively, averaging 3570 m, in accordance with the results based on the 3 stage thermal history. (authors)

  11. Provenance and post-sedimentary low-temperature evolution of the James Ross Basin sediments (Antarctic Peninsula) based on zircon and apatite fission-track analysis

    Czech Academy of Sciences Publication Activity Database

    Svojtka, Martin; Murakami, Masaki; Nývlt, D.; Macáková, J.; Filip, Jiří; Mixa, P.

    2007-01-01

    Roč. 71, 15 S1 (2007), A990-A990 ISSN 0046-564X. [Annual V. M. Goldschmidt Conference /17./. 19.08.2007-24.08.2007, Cologne] R&D Projects: GA MŠk 1K05030 Institutional research plan: CEZ:AV0Z30130516 Keywords : fission-track * zircon * apatite * James Ross, * Antarctica Subject RIV: DB - Geology ; Mineralogy

  12. Thermal history of the Krishna-Godavari basin, India: Constraints from apatite fission track thermochronology and organic maturity data

    Science.gov (United States)

    Sahu, Himansu S.; Raab, Matthias J.; Kohn, Barry P.; Gleadow, Andrew J. W.; Bal, Kiron D.

    2013-09-01

    The Krishna-Godavari (KG) basin, a passive margin Late Carboniferous to Holocene basin along the rifted east coast of India, includes the deltaic and inter-deltaic regions of the Krishna and Godavari rivers onshore and extends into the offshore. It is one of India's premier hydrocarbon-bearing basins. In an attempt to better understand the thermal history of the basin, apatite fission track (AFT) data has been obtained from six exploration wells (five onshore and one offshore). AFT thermal history models as well as other thermal indicators e.g. vitrinite reflectance (VR), Rock-Eval Tmax data reveal that the host rocks are currently at their maximum post-depositional temperatures and that any possible heating related to small-scale tectonism or rifting episodes in the basin bears little significance on the maturation of the sediments. In the case of one borehole (M-1) however, the organic maturity data reveals a period of Oligocene cooling across an unconformity when ∼1000 m of section was eroded due to falling sea-level. This information offers the potential for improved basin modeling of the KG basin.

  13. Analysis on the meso-neozoic subsidence and uplift history of the periphery of ordos basin using apatite fission track

    International Nuclear Information System (INIS)

    Liu Wusheng; Qin Mingkuan; Qi Fucheng; Xiao Shuqing; Wang Zhiming

    2008-01-01

    By analyzing apatite fission track data and inverse modeling, the thermal history of relevant rock assemblage has been studied qualitatively to semi-quantitatively in Ordos basin. Studies show that the basin was characterized by uplift in the east and subsidence in the west in Late Jurassic and Early Cretaceous and the eastern part of the basin was uplifted at the rate of 25 m/Ma, leading to the denudation of 1500-2000 m. In Late Cretaceous to the Early Eocene (90-230 Ma), the basin was uplifted as a whole, the southern and western parts of the basin were uplifted with the amplitude of less than 500 m. Since the Late Miocene (23 Ma to present), the whole basin was uplifted quickly and the uplifting rate was up to 45-108 m/Ma in the periphery of the basin, leading to the denudation of 1000-2500 m. Combined with the mineralization ages of sandstone type uranium deposits in the basin, it is concluded that the epigenesis of uranium mineralization mostly took place in the relatively quick uplifting stage of strata. (authors)

  14. Apatite fission-track evidence of widespread Eocene heating and exhumation in the Yukon-Tanana Upland, interior Alaska

    Science.gov (United States)

    Dusel-Bacon, C.; Murphy, J.M.

    2001-01-01

    We present an apatite fission-track (AFT) study of five plutonic rocks and seven metamorphic rocks across 310 km of the Yukon-Tanana Upland in east-central Alaska. Samples yielding ???40 Ma AFT ages and mean confined track lengths > 14 ??m with low standard deviations cooled rapidly from >120??C to 40 Ma suggest partial annealing and, therefore, lower maximum temperatures (???90-105??C). A few samples with single-grain ages of ???20 Ma apparently remained above ???50??C after initial cooling. Although the present geothermal gradient in the western Yukon-Tanana Upland is ???32??C/km, it could have been as high as 45??C/km during a widespread Eocene intraplate magmatic episode. Prior to rapid exhumation, samples with ???40 Ma AFT ages were >3.8-2.7 km deep and samples with >50 Ma AFT ages were >3.3-2.0 km deep. We calculate a 440-320 m/Ma minimum rate for exhumation of all samples during rapid cooling. Our AFT data, and data from rocks north of Fairbanks and from the Eielson deep test hole, indicate up to 3 km of post-40 Ma vertical displacement along known and inferred northeast-trending high-angle faults. The predominance of 40-50 Ma AFT ages throughout the Yukon-Tanana Upland indicates that, prior to the post-40 Ma relative uplift along some northeast-trending faults, rapid regional cooling and exhumation closely followed the Eocene extensional magmatism. We propose that Eocene magmatism and exhumation were somehow related to plate movements that produced regional-scale oroclinal rotation, northward translation of outboard terranes, major dextral strike-slip faulting, and subduction of an oceanic spreading ridge along the southern margin of Alaska.

  15. Mesozoic exhumation in the coastal region of NW Iberia: Preliminary constraints from apatite fission-track cooling ages

    Science.gov (United States)

    Alvarez-Marrón, Joaquina; Barbero, Luis; Menéndez-Duarte, Rosana; Fernández, Susana

    2013-04-01

    Apatite fission-track (AFT) ages from the Iberian Massif, along the northern coastal region in Galicia are presented. The study aims at unravelling the exhumation history of this higher topography coastal region, the so-called Rías Altas region, next to the northern Iberian margin. The rough topography region is bound to the south by the WNW-ESE trending As Pontes dextral strike-slip fault zone. This fault was active since ca. 30 Ma (Rupelian) up to ca. 21 Ma (Aquitanian). The area comprises mainly Late Proterozoic to Paleozoic metamorphic and igneous rocks from the hinterland of the Variscan orogen. A N-S AFT ages profile from the coast to the southern block of the As Pontes fault reveal progressively younger ages toward the south with the oldest ages (242 ± 12 Ma) located near the coast and the youngest age being 124 ± 7 Ma. The AFT ages at both sides of the As Pontes fault in samples taken at the same elevation are similar within error (124 ± 7and 127 ± 7 Ma) indicating that this strike-slip fault did not cause significant differential exhumation during Oligocene-Early Miocene times. Another important feature shown by these data is that the age-elevation relationship (AER) is negative, the youngest ages being located at the highest elevation (ca. 1000 m. a. s. l). This agrees with recent published data from the easternmost part of the present study area and is an indication of Post-Early Cretaceous long residence time within the upper 2 or 3 km of the crust at temperatures lower than those of the apatite partial annealing zone (60 to 120°C). We interpret the registered exhumation history as mostly related to rifting processes in Pre-Early Cretaceous times. Possibly recording surface processes associated to the two stage rifting episodes in the Triassic and in the Late Jurassic-Early Cretaceous that culminated with formation of the north Iberian Margin. The negative AER suggests that since Early Cretaceous times the whole area underwent topographic changes

  16. Integrated Vitrinite Reflectance and Apatite Fission Track Thermocronology of the Lower Karoo rocks in the Moatize Basin, Tete Province, Mozambique.

    Science.gov (United States)

    Fernandes, Paulo; Cogné, Nathan; Rodrigues, Bruno; Jorge, Raul; Marques, João

    2014-05-01

    The Karoo in Mozambique is represented by Late Carboniferous to Late Triassic sediments that were deposited in rift basins that fringe or developed between Proterozoic cratons. In Tete Province, central-west Mozambique, the Karoo is well represented along the Zambezi river valley forming several intra-cratonic basins separated by horsts consisting of igneous and high grade metamorphic Proterozoic rocks. One of the main horst blocks is located between the Cahora Bassa region and Tete city, separating the Middle Zambezi Basin and the Lower Zambezi Basin. The area of study is located in the Moatize Basin, one of many small basins that form the Lower Zambezi Basin. The stratigraphy of this basin consists of several sedimentary formations that record changes in depositional environment and palaeoclimate from glacial (Vúzi Formation - Lower Permian) at the base, through wet to temperate in the middle (Moatize Formation - Lower Permian), to warm arid at the top of the succession (Matinde and Cádzi formations - Middle to Upper Permian). The Upper Karoo volcanics of Early Jurassic age do not crop out in the Moatize Basin. One of the most remarkable characteristics of the Moatize Basin is the richness of coal deposits present in the Lower Permian Moatize Formation. Two coal exploration boreholes (DW123 - T.D. 489 m and DW132 - T.D. 516 m) drilled in the Moatize Basin were studied by means of vitrinite reflectance (VR) and apatite fission track analysis (AFTA), in order to assess their burial and uplift histories. The two boreholes intersected only Moatize Formation lithologies. VR increases in the two borehole sections from ca. 1.30-1.32 % Ro at the top to ca. 1.52-1.69 % Ro at the bottom, indicating medium to low volatile coal rank. Modelled VR data from the two boreholes indicate palaeogeothermal gradients between 40 and 56ºC/km, possible related to basin forming processes. Fission track ages increase from 84 Ma and 102 Ma at the bottom to 138 Ma and 146 Ma at the top

  17. Phanerozoic burial and exhumation history of southernmost Norway estimated from apatite fission-track analysis data and geological observations

    Science.gov (United States)

    Japsen, Peter; Green, Paul F.; Bonow, Johan M.; Chalmers, James A.; Rasmussen, Erik S.

    2016-04-01

    We present new apatite fission-track analysis (AFTA) data from 27 basement samples from Norway south of ~60°N. The data define three events of cooling and exhumation that overlap in time with events defined from AFTA in southern Sweden (Japsen et al. 2015). The samples cooled below palaeotemperatures of >100°C in a major episode of Triassic cooling as also reported by previous studies (Rohrman et al. 1995). Our study area is just south of the Hardangervidda where Cambrian sediments and Caledonian nappes are present. We thus infer that these palaeotemperatures reflect heating below a cover that accumulated during the Palaeozoic and Triassic. By Late Triassic, this cover had been removed from the Utsira High, off SW Norway, resulting in deep weathering of a granitic landscape (Fredin et al. 2014). Our samples were therefore at or close to the surface at this time. Palaeotemperatures reached ~80°C prior to a second phase of cooling and exhumation in the Jurassic, following a phase of Late Triassic - Jurassic burial. Upper Jurassic sandstones rest on basement near Bergen, NW of our study area (Fossen et al. 1997), and we infer that the Jurassic event led to complete removal of any remaining Phanerozoic cover in the region adjacent to the evolving rift system prior to Late Jurassic subsidence and burial. The data reveal a third phase of cooling in the early Miocene when samples that are now near sea level cooled below palaeotemperatures of ~60°C. For likely values of the palaeogeothermal gradient, such palaeotemperatures correspond to burial below rock columns that reach well above the present-day landscape where elevations rarely exceed 1 km above sea level. This implies that the present-day landscape was shaped by Neogene erosion. This is in agreement with the suggestion of Lidmar-Bergström et al. (2013) that the near-horizontal Palaeic surfaces of southern Norway are the result of Cenozoic erosion to sea level followed by uplift to their present elevations in a

  18. Erosion, transport and deposition along the South-Central Chilean margin: the detrital apatite fission track perspective

    Science.gov (United States)

    Heberer, B.; Behrmann, J. H.; Rahn, M.

    2009-04-01

    Detrital fission track analysis has become a powerful tool for the study of sediment provenance and exhumation of orogens. Many studies focus on zones of continental collision with no or little volcanic activity, but there are less examples from active arc-trench systems. This type of orogen has a strong magmatic signature, and upper plate tectonothermal histories that are distinct from collisional mountain belts. Uplift and denudation histories are different, and may comprise long periods of relative upper plate stability, which can be identified by thermochronological methods. In this study, we apply apatite fission track (AFT) single-grain age dating and sediment provenance analysis to modern and Pleistocene turbiditic sediments from the Chilean trench system (trench fans, trench fill, continental slope) complemented by a study of modern sediment samples from large Chilean rivers. The study area covers a ca. 1200 km long north to south transect (29°S to 47°S) encompassing areas of strongly variable characteristics, such as large latitudinal gradients in climate and terrigenous sediment input into the trench. This approach allows us (1) to trace sediment pathways on- and offshore focusing on all parts of the system, i.e. the bedrock sequences of the source, the fluvial transport system, and finally the sink within the trench, (2) to label those units that are under- and overrepresented, respectively, in the sink, making use of drainage system modeling and comparisons of grain age distributions to the cooling age pattern of the bedrocks of the feeder area, and (3) to test thermochronological concepts, such as a negligible transport time within the lag-time concept. We find that AFT dating and sediment analysis point to opposing major sediment sources in the Chilean margin: Whereas sediment petrography mirrors the evacuation of large volumes of volcanic detritus, reflecting the high rate of erosion of volcanic edifices, no such young volcanic signal is seen in

  19. Exhumation history of the Anqing Orefield in the Lower Yangtze River Metallogenic Belt: Evidence from apatite fission-track thermochronology

    Science.gov (United States)

    Li, X.; Yang, X.

    2017-12-01

    The Lower Yangtze River Metallogenic Belt (LYRMB) is one of the most important Cu-Au-Fe polymetallic belts in China. These deposits along the Yangtze River region have been related to the Yanshanian intrusive rocks in the Mesozoic. The Anqing orefield is located in the northwestern Anqing, southwestern Anhui Province, eastern China, along the Lower Yangtze River Belt. Here, we report new apatite fission-track (AFT) thermochronology of the granitoids ( 130 Ma for zircon U-Pb age) associated with the Anqing orefields to reveal the exhumation history of the Anqing orefields in LYRMB, eastern China. AFT ages from 54.4±2.1 to 63.9±3.4 Ma with mean measured track lengths between 12.4±1.8 and 13.1±1.4 μm, were obtained for the granitoids sampled from the ore fields in the Anqing orefield, and AFT age of 36.3±1.3 Ma with mean track length of 12.3±2.3μm for the granitoids adjacent to the south Tan-Lu fault. A long, slow exhumation ( 60-15 Ma), and a short, rapid tectonic exhumation (15-0 Ma) have been identified in the study region based on the AFT data and modeling results for the samples from the ore fields. The results show that the granitoids underwent roughly similar cooling, and inferred exhumation pattern. Assuming a steady-state paleogeothermal gradient of 35ºC/km founded on geological setting, the exhumations of 570 m and 1140 m, were achieved in the Anqing orefield, during 60-15 Ma and 15-0 Ma, respectively. Further, the AFT age of the granitoids adjacent to the south Tan-Lu fault is less than the AFT ages of the granitoids associated with the ore fields, possibly owing to the activation of the Tan-Lu fault in the Cenozoic. The exhumation history of the Anqing orefields may be closely response to the Pacific Plate subduction in the Cenozoic, which could be implications for the preservation potential of ore bodies in the Anqing orefield. This work is supported by the National Natural Science Foundation of China (41372227), and the DREAM project of MOST

  20. Conditions for veining in the Barrandian Basin (Lower Palaeozoic), Czech Republic: evidence from fluid inclusion and apatite fission track analysis

    Science.gov (United States)

    Suchy, V.; Dobes, P.; Filip, J.; Stejskal, M.; Zeman, A.

    2002-04-01

    The interplay between fracture propagation and fluid composition and circulation has been examined by deciphering vein sequences in Silurian and Devonian limestones and shales at Kosov quarry in the Barrandian Basin. Three successive vein generations were recognised that can be attributed to different stages of a basinal cycle. Almost all generations of fracture cements host abundant liquid hydrocarbon inclusions that indicate repeated episodes of petroleum migration through the strata during burial, tectonic compression and uplift. The earliest veins that propagated prior to folding were displacive fibrous "beef" calcite veins occurring parallel to the bedding of some shale beds. Hydrocarbon inclusions within calcite possess homogenisation temperatures between 58 and 68 °C and show that the "beef" calcites originated in the deeper burial environment, during early petroleum migration from overpressured shales. E-W-striking extension veins that postdate "beef" calcite formed in response to Variscan orogenic deformations. Based on apatite fission track analysis (AFTA) data and other geological evidence, the veins probably formed 380-315 Ma ago, roughly coinciding with peak burial heating of the strata, folding and the intrusion of Variscan synorogenic granites. The veins that crosscut diagenetic cements and low-amplitude stylolites in host limestones are oriented semi-vertically to the bedding plane and are filled with cloudy, twinned calcite, idiomorphic smoky quartz and residues of hardened bitumen. Calcite and quartz cements contain abundant blue and blue-green-fluorescing primary inclusions of liquid hydrocarbons that homogenise between 50 and 110 °C. Geochemical characteristics of the fluids as revealed by gas chromatography-mass spectrometry, particularly the presence of olefins and parent aromatic hydrocarbons (phenonthrene), suggest that the oil entrapped in the inclusions experienced intense but geologically fast heating that resulted in thermal pyrolysis

  1. Preliminary calibration of fission-track zeta constant for NBS SRM 962a using fish canyon tuff apatite age standard

    International Nuclear Information System (INIS)

    Ng Inn Khuan; Gui Ah Auu

    1991-01-01

    The Zeta method for the calibration of fission-track dating against other radiometric dating techniques has been described by Hurford and Green (1983). In this paper, the data for the Zeta calibration were obtained using 4π -Conversion Procedure (Suzuki et. al., 1984). The preliminary Zeta value determined from this work was found to be 224.52 ± 38.73, showing significant difference from values obtained by workers elsewhere using equivalent standard glass dosimeter. Factors that might have contributed to such discrepancy are discussed. From this study and work done by other fission-track workers, it is obvious that a wide range of Zeta values are in common use. However consistency in track-counting remains the prime factor for getting reliable ages for unknown samples

  2. Thermal and tectonic history of the Ordos Basin, China: Evidence from apatite fission track analysis, vitrinite reflectance, and K-Ar dating

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Meng-Wei; Behr, H.J.; Ahrendt, H.; Wemmer, K. [Univ. of Goettingen (Germany); Zhan-Li Ren; Zhong-Yuan Zhao [Northwest Univ., Xi`an (China)

    1996-07-01

    Apatite fission track analysis, vitrinite reflectance data, and K-Ar dating of Permian-Carboniferous and Mesozoic core samples have been successfully integrated to reconstruct the thermal and tectonic history of the Ordos basin, China. Apatite fission track ages of Carboniferous-Jurassic sedimentary rocks range between 3 and 137 Ma, and are significantly younger than the stratigraphic ages. Confined fission track lengths demonstrate exclusively mixed length distribution, indicating complex thermal history. The data suggest that the samples must have all experienced higher paleotemperatures in the past. Mean virtinite reflectance values (R{sub o}) of the Triassic rocks range from 0.61 to 1.06%, giving a high coalification gradient of 0.36%/km and suggesting a high paleothermal gradient of 57{degrees}C/km. Permian-Carboniferous rocks have R{sub o} values on the order of 1.0-3.0%, and locally up to 4.0-6.0%. Some high R{sub o} values coincide with positive gravity and magnetic anomalies. K-Ar dating on Permian-Triassic samples reveals distinct illitization at 170-160 Ma, during which a thermal event occurred due to subsurface magmatic intrusion related to the early Yanshanian movement. The petroleum source rocks of the Upper Triassic experienced peak temperatures ranging form 90 to 160{degrees}C, corresponding to the oil window, and Permian-Carboniferous source rocks were heated to more than 150{degrees}C, passing through and out of the gas window. Due to rapid uplift and erosion in response to the rise of the Qinghai-Tibet plateau associated with the Asia-India collision and the Himalyan orogeny, cooling has taken place at least since approximately 23 Ma. The difference in the rate and amount of uplift between the eastern and western parts of the basin resulted in differential uplift and the present-day structural pattern of the basin.

  3. Long-term landscape evolution of the South Atlantic "passive" continental margin in Eastern Argentina using apatite fission-track thermochronology

    Science.gov (United States)

    Pfister, Sabrina; Kollenz, Sebastian; Glasmacher, Ulrich A.

    2015-04-01

    To understand the evolution of the "passive" continental margin in Argentina low temperature thermochronology is an appropriate method, which might lead to new insights in this area. The Tandilia System, also called Sierras Septentrionales, is located south of the Río de la Plato Craton in eastern Argentina in the state of Buenos Aires. North of the hills the Salado basin is located whereas the Claromecó basin is situated south of the mountain range. In contrary to most basins along the South American "passive" continental margin, the Tandilia-System and the neighbouring basins trend perpendicular to the coast line. The topography is fairly flat with altitudes up to 350 m. The igneous-metamorphic basement is pre-Proterozoic in age and build up of mainly granitic-tonalitic gneisses, migmatites, amphibolites, some ultramafic rocks and granitoid plutons. It is overlain by a series of Neoproterozoic to early Paleozoic sedimentary rocks (Cingolani 2011), like siliciclastic rocks, dolostones, shales and limestones (Demoulin 2005). The aim of the study is to quantify the long-term landscape evolution of the "passive" continental margin in eastern Argentina in terms of thermal, exhumation and tectonic evolution. For that purpose, samples were taken from the basement of the Sierra Septentrionales and analyzed with the apatite fission-track method. Further 2-D thermokinematic modeling was conducted with the computer code HeFTy (Ketcham 2005; Ketcham 2007; Ketcham et al. 2009). Because there are different hypotheses in literature regarding the geological evolution of this area two different models were generated, one after Demoulin et al. (2005) and another after Zalba et al.(2007). All samples were taken from the Neoproterozoic igneous-metamorphic basement. Apatite fission-track ages range from 101.6 (9.4) to 228.9 (22.3) Ma, and, therefore, are younger than their formation age, indicating all samples have been thermally reset. Six samples accomplished enough confined

  4. Tectono-thermal evolution of the southwestern Alxa Tectonic Belt, NW China: Constrained by apatite U-Pb and fission track thermochronology

    Science.gov (United States)

    Song, Dongfang; Glorie, Stijn; Xiao, Wenjiao; Collins, Alan S.; Gillespie, Jack; Jepson, Gilby; Li, Yongchen

    2018-01-01

    The Central Asian Orogenic Belt (CAOB) is regarded to have undergone multiple phases of intracontinental deformation during the Meso-Cenozoic. Located in a key position along the southern CAOB, the Alxa Tectonic Belt (ATB) connects the northernmost Tibetan Plateau with the Mongolian Plateau. In this paper we apply apatite U-Pb and fission track thermochronological studies on varieties of samples from the southwestern ATB, in order to constrain its thermal evolution. Precambrian bedrock samples yield late Ordovician-early Silurian ( 430-450 Ma) and late Permian ( 257 Ma) apatite U-Pb ages; the late Paleozoic magmatic-sedimentary samples yield relatively consistent early Permian ages from 276 to 290 Ma. These data reveal that the ATB experienced multiple Paleozoic tectono-thermal events, as the samples passed through the apatite U-Pb closure temperature ( 350-550 °C). We interpret these tectonic events to record the long-lived subduction-accretion processes of the Paleo-Asian Ocean during the formation of the southern CAOB, with possible thermal influence of the Permian Tarim mantle plume. Apatite fission track (AFT) data and thermal history modelling reveal discrete low-temperature thermal events for the ATB, inducing cooling/reheating through the AFT partial annealing zone ( 120-60 °C). During the Permian, the samples underwent rapid cooling via exhumation or denudation from deep crustal levels to temperatures < 200 °C. Subsequent thermal events in the Triassic were thought to be associated with the final amalgamation of the CAOB or the closure of the Paleotethys. During the Jurassic-Cretaceous the study area experienced heating by burial, followed by renewed cooling, which may be related with the construction and subsequent collapse of the Mongol-Okhotsk Orogeny, or the Lhasa-Eurasia collision and subsequent slab break-off. These results indicate that the ATB may have been stable after late Cretaceous in contrast to the Qilian Shan and Tianshan. Finally, our

  5. Differential denudations of the Argentera Alpine external crystalline massif (SE France) revealed by fission track thermo-chronology (zircons, apatites)

    International Nuclear Information System (INIS)

    Bigot-Cormier, F.; Sosson, M.; Poupeau, G.

    2000-01-01

    A fission track thermo-chronological study of the Argentera external crystalline massif (western Alps) reveals tectonic blocks with differential vertical motions. The northwest area cooled down about 300 deg. C from the Upper Cretaceous and the remaining of the massif crossed the 250 deg. C isotherm in the 29-20 Ma time interval, after the internal nappe over-thrust. Moreover the massif cooled below 120 deg. C more than 12.5 Ma ago and its denudation rate increased locally 6 Ma ago and more generally since 3.5 Ma in relation with the reverse motion along the Bersezio fault. (authors)

  6. New insights on the geological evolution of the continental margin of Southeastern Brazil derived from zircon and apatite (U-Th-Sm)/He and fission-track data

    Science.gov (United States)

    Krob, Florian; Stippich, Christian; Glasmacher, Ulrich A.; Hackspacher, Peter

    2017-04-01

    New insights on the geological evolution of the continental margin of Southeastern Brazil derived from zircon and apatite (U-Th-Sm)/He and fission-track data Krob, F.C.1, Stippich, C. 1, Glasmacher, U.A.1, Hackspacher, P.C.2 (1) Institute of Earth Sciences, Research Group Thermochronology and Archaeometry, Heidelberg University, INF 234, 69120, Heidelberg, Germany (2) Instituto de Geociências e Ciências Exatas, Universidade Estadual Paulista, Av. 24-A, 1515 Rio Claro, SP, 13506-900, Brazil Passive continental margins are important geoarchives related to mantle dynamics, the breakup of continents, lithospheric dynamics, and other processes. The main concern yields the quantifying long-term lithospheric evolution of the continental margin between São Paulo and Laguna in southeastern Brazil since the Neoproterozoic. We put special emphasis on the reactivation of old fracture zones running into the continent and their constrains on the landscape evolution. In this contribution, we represent already consisting thermochronological data attained by fission-track and (U-Th-Sm)/He analysis on apatites and zircons. The zircon fission-track ages range between 108.4 (15.0) and 539.9 (68.4) Ma, the zircon (U-Th-Sm)/He ages between 72.9 (5.8) and 427.6 (1.8) Ma whereas the apatite fission-track ages range between 40.0 (5.3) and 134.7 (8.0) Ma, and the apatite (U-Th-Sm)/He ages between 32.1 (1.52) and 92.0 (1.86) Ma. These thermochronological ages from metamorphic, sedimentary and intrusive rocks show six distinct blocks (Laguna, Florianópolis, Curitiba, Ilha Comprida, Peruibe and Santos) with different evolution cut by old fracture zones. Furthermore, models of time-temperature evolution illustrate the differences in Pre- to post-rift exhumation histories of these blocks. The presented data will provide an insight into the complex exhumation history of the continental margin based on the existing literature data on the evolution of the Paraná basin in Brazil and the latest

  7. Evolution of the Chos Malal and Agrio fold and thrust belts, Andes of Neuquén: Insights from structural analysis and apatite fission track dating

    Science.gov (United States)

    Rojas Vera, E. A.; Mescua, J.; Folguera, A.; Becker, T. P.; Sagripanti, L.; Fennell, L.; Orts, D.; Ramos, V. A.

    2015-12-01

    The Chos Malal and Agrio fold and thrust belts are located in the western part of the Neuquén basin, an Andean retroarc basin of central-western Argentina. Both belts show evidence of tectonic inversion at the western part during Late Cretaceous times. The eastern part is dominated by late Miocene deformation which also partially reactivated the western structures. This work focuses on the study of the regional structure and the deformational event that shaped the relief of this part of the Andes. Based on new field work and structural data and previously published works a detailed map of the central part of the Neuquén basin is presented. Three regional structural cross sections were surveyed and balanced using the 2d Move™ software. In order to define a more accurate uplift history, new apatite fission track analyses were carried on selected structures. These data was used for new thermal history modeling of the inner part of the Agrio and Chos Malal fold and thrust belts. The results of the fission track analyses improve the knowledge of how these fold and thrust belts have grown trough time. Two main deformational events are defined in Late Cretaceous to Paleocene and Late Miocene times. Based on this regional structural analysis and the fission track data the precise location of the orogenic front for the Late Cretaceous-Paleocene times is reconstructed and it is proposed a structural evolution of this segment of the Andes. This new exhumation data show how the Late Cretaceous to Paleocene event was a continuous and uninterrupted deformational event.

  8. The thermal history of the Karoo Moatize-Minjova Basin, Tete Province, Mozambique: An integrated vitrinite reflectance and apatite fission track thermochronology study

    Science.gov (United States)

    Fernandes, Paulo; Cogné, Nathan; Chew, David M.; Rodrigues, Bruno; Jorge, Raul C. G. S.; Marques, João; Jamal, Daud; Vasconcelos, Lopo

    2015-12-01

    The Moatize-Minjova Basin is a Karoo-aged rift basin located in the Tete Province of central Mozambique along the present-day Zambezi River valley. In this basin the Permian Moatize and Matinde formations consist of interbedded carbonaceous mudstones and sandstones with coal seams. The thermal history has been determined using rock samples from two coal exploration boreholes (ca. 500 m depth) to constrain the burial and exhumation history of the basin. Organic maturation levels were determined using vitrinite reflectance and spore fluorescence/colour. Ages and rates of tectonic uplift and denudation have been assessed by apatite fission track analysis. The thermal history was modelled by inverse modelling of the fission track and vitrinite reflectance data. The Moatize Formation attained a coal rank of bituminous coals with low to medium volatiles (1.3-1.7%Rr). Organic maturation levels increase in a linear fashion downhole in the two boreholes, indicating that burial was the main process controlling peak temperature maturation. Calculated palaeogeothermal gradients range from 59 °C/km to 40 °C/km. According to the models, peak burial temperatures were attained shortly (3-10 Ma) after deposition. Apatite fission track ages [146 to 84 Ma (Cretaceous)] are younger than the stratigraphic age. Thermal modelling indicates two episodes of cooling and exhumation: a first period of rapid cooling between 240 and 230 Ma (Middle - Upper Triassic boundary) implying 2500-3000 m of denudation; and a second period, also of rapid cooling, from 6 Ma (late Miocene) onwards implying 1000-1500 m of denudation. The first episode is related to the main compressional deformation event within the Cape Fold Belt in South Africa, which transferred stress northwards on pre-existing transtensional fault systems within the Karoo rift basins, causing tectonic inversion and uplift. During the Mesozoic and most of the Cenozoic the basin is characterized by very slow cooling. The second period

  9. Application of fission track analysis to hydrocarbon exploration

    International Nuclear Information System (INIS)

    Duddy, I.R.; Green, P.F.; Gleadow, A.J.W.; Marshallsea, S.; Tingate, P.; Laslett, G.M.; Hegarty, K.A.; Lovering, J.F.

    1985-01-01

    The temperature range over which fission tracks in apatite show observable annealing effects coincides with that responsible for the maximum generation of liquid hydrocarbons. Work is currently in progress in a number of Australian and overseas sedimentary basins, applying Apatite Fission Track Analysis (AFTA) to investigate the thermal evolution of these hydrocarbon prospective regions

  10. Post-Triassic thermal history of the Tazhong Uplift Zone in the Tarim Basin, Northwest China: Evidence from apatite fission-track thermochronology

    Directory of Open Access Journals (Sweden)

    Caifu Xiang

    2013-11-01

    Full Text Available The Tarim Basin is a representative example of the basins developed in the northwest China that are characterized by multiple stages of heating and cooling. In order to better understand its complex thermal history, apatite fission track (AFT thermochronology was applied to borehole samples from the Tazhong Uplift Zone (TUZ. Twelve sedimentary samples of Silurian to Triassic depositional ages were analyzed from depths coinciding with the apatite partial annealing zone (∼60–120 °C. The AFT ages, ranging from 132 ± 7 Ma (from a Triassic sample to 25 ± 2 Ma (from a Carboniferous sample, are clearly younger than their depositional ages and demonstrate a total resetting of the AFT thermometer after deposition. The AFT ages vary among different tectonic belts and decrease from the No. Ten Faulted Zone (133–105 Ma in the northwest, the Central Horst Zone in the middle (108–37 Ma, to the East Buried Hill Zone in the south (51–25 Ma. Given the low magnitude of post-Triassic burial heating evidenced by low vitrinite reflectance values (Ro < 0.7%, the total resetting of the AFT system is speculated to result from the hot fluid flow along the faults. Thermal effects along the faults are well documented by younger AFT ages and unimodal single grain age distributions in the vicinity of the faults. Permian–early Triassic basaltic volcanism may be responsible for the early Triassic total annealing of those samples lacking connectivity with the fault. The above arguments are supported by thermal modeling results.

  11. Onshore and offshore apatite fission-track dating from the southern Gulf of California: Insights into the time-space evolution of the rifting

    Science.gov (United States)

    Balestrieri, Maria Laura; Ferrari, Luca; Bonini, Marco; Duque-Trujillo, Jose; Cerca, Mariano; Moratti, Giovanna; Corti, Giacomo

    2017-11-01

    We present the results of a apatite fission-track (AFT) study on intrusive rocks in the southern Gulf of California, sampled along the eastern margin of Baja California Sur (western rift margin), as well as from islands and submerged rifted blocks within the Gulf of California, and from the conjugate Mexican margin (Nayarit state). For most of the samples U-Pb zircon and 40Ar-39Ar mineral ages were already available (Duque-Trujillo et al., 2015). Coupled with the new AFT data these ages provide a more complete information on cooling after emplacement. Our samples span a wide range of ages between 5.5 ± 1.1 and 73.7 ± 5.8 Ma, and show a general spatial distribution, with late Miocene AFT ages (about 6 Ma) aligned roughly NW-SE along a narrow offshore belt, parallel to Baja California Peninsula, separating older ages on both sides. This pattern suggests that in Late Miocene, deformation due to plate transtension focused at the eastern rheological boundary of the Baja California block. Some Early Miocene AFT ages onshore Baja California could be related to plutons emplaced at shallow depths and thermal resetting associated with the onset of volcanism at 19 Ma in this part of the Peninsula. On the other hand, an early extensional event similar to that documented in the eastern Gulf cannot be ruled out in the westernmost Baja California.

  12. Apatite fission-track thermochronometric constraints on the exhumation and evolution of the southeastern Indian (Tamil Nadu) passive margin and the role of structural inheritance

    Science.gov (United States)

    De Grave, Johan; Glorie, Stijn; Singh, Tejpal; Van Ranst, Gerben; Nachtergaele, Simon

    2017-04-01

    After rifting from Gondwana in the Late Jurassic - Early Cretaceous, and subsequent opening of the Indian Ocean basin, the continental margins of India developed into typical passive margins. Extensional tectonic forces and thermal subsidence gave rise to the formation of both on-shore and off-shore basins along the southeastern passive margin of the Indian continent, along the Tamil Nadu coast. There, basins such as the Cauvery and Krishna-Godavari basin, accumulated Meso- and Cenozoic (Early Cretaceous to recent) detrital sediments coming off the rifted blocks and the Tamil Nadu hinterland. In places, deep rift basins have accumulated up to over 3000 m of sediments. The continental basement of Tamil Nadu is chiefly composed of metamorphic rocks of the Archean to Palaeoproterozoic Eastern Dharwar Craton and the coeval Southern Granulite Terrane (e.g. Peucat et al., 2013). Several crustal scale shear zones crosscut this assemblage and at least some are considered to represent Gondwanan sutures (Santosh et al., 2012). Smaller, younger granitoid plutons intrude the basement at several locations and most of these are of Late Neoproterozoic age (Glorie et al., 2014). In this work metamorphic basements rocks and the younger granitoids were sampled for a apatite fission-track (AFT) thermochronometric study. A North-South profile from Chennai to Thanjavur mainly transects the Salem block of the Southern Granulite Terrane, and crosscuts several crustal scale shear zones, such as the Cauvery, Salem-Attur and Gangavalli shear zones. Apatites from over 30 samples were used in this study. AFT ages all range between about 190 and 120 Ma (Jurassic - Early Cretaceous). These mainly represent the slow, shallow exhumation of the basement during the rift and early drift phase of the Indian plate from Gondwana. AFT mean track lengths vary between 11 and 13 µm and are typical of slowly exhumed basement. Thermal history modelling (using the QTQt software by Gallagher, 2012) confirms

  13. Late Mesozoic and Cenozoic thermotectonic history of the Mexican Pacific margin (18 to 25°N): new insight from apatite and zircon fission-track analysis of coastal and offshore plutonic rocks

    Science.gov (United States)

    Calmus, Thierry; Poupeau, Gérard; Bourgois, Jacques; Michaud, François; Mercier de Lépinay, Bernard; Labrin, Erika; Azdimousa, Ali

    1999-06-01

    Apatite and zircon fission-track dating was used to constrain cooling histories on granitic samples taken from the offshore Acapulco trench batholith and onshore Manzanillo and Puerto Vallarta batholiths located along the southwestern active margin of Mexico, and from the La Paz batholith of southern Baja California. The apatite data indicate that many of the samples in the Manzanillo, Acapulco trench batholiths cooled rapidly below 60°C shortly after emplacement between 70 and 55 Ma. The La Paz batholith and the sample NM-20-08 of the Acapulco trench batholith experienced an older and slower cooling across the apatite partial annealing zone. The zircon fission-track ages obtained from two samples of the Puerto Vallarta batholith indicate a rapid cooling from 250 to 110°C between 54 and 50 Ma. This non-coeval cooling of batholiths at two different depths is probably due to uplift and erosion associated with the Laramide event in southwestern Mexico. The three samples from the Puerto Vallarta batholith suggest a younger evolution across low temperatures with two flat stages located near the base of the apatite partial annealing zone and above it. The first flat stage suggests that the denudation or rock uplift rate was reduced at a depth corresponding to the base of the apatite partial annealing zone. The younger single apatite ages of the Puerto Vallarta batholith, and the last common cooling of the other batholiths indicate the mild thermal influences of both the Plio-Pleistocene Trans-Mexican Volcanic Belt and the opening of the Gulf of California.

  14. Apatite fission-track evidence for regional exhumation in the subtropical Eocene, block faulting, and localized fluid flow in east-central Alaska

    Science.gov (United States)

    Dusel-Bacon, Cynthia; Bacon, Charles R.; O'Sullivan, Paul B.; Day, Warren C.

    2016-01-01

    The origin and antiquity of the subdued topography of the Yukon–Tanana Upland (YTU), the physiographic province between the Denali and Tintina faults, are unresolved questions in the geologic history of interior Alaska and adjacent Yukon. We present apatite fission-track (AFT) results for 33 samples from the 2300 km2 western Fortymile district in the YTU in Alaska and propose an exhumation model that is consistent with preservation of volcanic rocks in valleys that requires base level stability of several drainages since latest Cretaceous–Paleocene time. AFT thermochronology indicates widespread cooling below ∼110 °C at ∼56–47 Ma (early Eocene) and ∼44–36 Ma (middle Eocene). Samples with ∼33–27, ∼19, and ∼10 Ma AFT ages, obtained near a major northeast-trending fault zone, apparently reflect hydrothermal fluid flow. Uplift and erosion following ∼107 Ma magmatism exposed plutonic rocks to different extents in various crustal blocks by latest Cretaceous time. We interpret the Eocene AFT ages to suggest that higher elevations were eroded during the Paleogene subtropical climate of the subarctic, while base level remained essentially stable. Tertiary basins outboard of the YTU contain sediment that may account for the required >2 km of removed overburden that was not carried to the sea by the ancestral Yukon River system. We consider a climate driven explanation for the Eocene AFT ages to be most consistent with geologic constraints in concert with block faulting related to translation on the Denali and Tintina faults resulting from oblique subduction along the southern margin of Alaska.

  15. A Modern Analog to the Depositional Age Problem: Zircon and Apatite Fission Track and U-Pb Age Distributions by LA-ICP-MS

    Science.gov (United States)

    Donelick, H. M.; Donelick, M. B.; Donelick, R. A.

    2012-12-01

    Sand from three river systems in North Idaho (Snake River near Lewiston, Clearwater River near Lewiston and the Salmon River near White Bird) and two regional ash fall events (Mt. Mazama and Mt. St. Helens) were collected for zircon U-Pb detrital age analysis. Up to 120 grains of zircon per sample were ablated using a Resonetics M-50 193 nm ArF Excimer laser ablation (LA) system and the Pb, Th, and U isotopic signals were quantified using an Agilent 7700x quadrupole inductively coupled plasma-mass spectrometer (ICP-MS). Isotopic signals for major, minor, and trace elements, including all REEs, were also monitored. The youngest zircon U-Pb ages from the river samples were approximately 44 Ma; Cenozoic Idaho Batholith and Precambrian Belt Supergroup ages were well represented. Significant common Pb contamination of the Clearwater River sample (e.g., placer native Cu was observed in the sample) precluded detailed analysis of the zircon U-Pb ages but no interpretable ages Mazama 7,700 years ago, and no doubt other events during the Quaternary. Work currently in progress seeks to address bias against near 0 Ma ages in the catchment areas due to: a) small, local ash fall grain sizes and b) overwhelming number of older grains relative to the ash fall grains. Data from Mt. St. Helens ash from several localities near the mountain (Toutle River and Maple Flats, WA) and several far from the mountain (Spokane, WA; Princeton, ID; Kalispell, MT) and Mt. Mazama ash fall deposits near Lewiston, ID and Spokane, WA will be presented to address these possibilities. Additionally, fission track and U-Pb ages from apatites collected from these river and ash fall samples will also be shown to help constrain the problem.

  16. Burial and exhumation history of southern Sweden estimated from apatite fission-track data, stratigraphic landform analysis and the geological record

    Science.gov (United States)

    Japsen, Peter; Green, Paul F.; Lidmar-Bergström, Karna; Bonow, Johan M.; Erlström, Mikael

    2014-05-01

    We present new apatite fission-track analysis (AFTA) data from 87 samples of basement and sediment from southern Sweden, including samples from a 1.7 km deep borehole. The new AFTA data allow us to confirm the development of the South Swedish Dome as inferred from stratigraphic landform analysis (e.g. Lidmar-Bergström et al., 2013) and also to define the timing and magnitude of the events of burial and exhumation that shaped this prominent feature. Southern Sweden underwent a complex Palaeozoic - early Triassic history of burial and exhumation, but after a mid-Triassic event of uplift and exhumation, rocks on the Sub-Cambrian Peneplain cooled from palaeotemperatures ≥100°C. This event, that also affected southern Norway, West and East Greenland, marks an important phase in the breakup of Pangea. A second, regional phase of cooling and exhumation affected the area in the mid-Jurassic and eventually lead to stripping of the basement along the western and southern flanks of the South Swedish Dome prior to Late Cretaceous subsidence and burial and thus to formation of the sub-Cretaceous hilly relief. This event affected much of NW Europe as well as West and East Greenland, and it is coeval with the initial opening of the central Atlantic. A third, regional phase of cooling and exhumation from palaeotemperatures of 50-60°C took place in the Miocene and lead to the formation of the South Småland Peneplain. This phase affected southern Scandinavia but has no counterpart in Greenland. A final uplift phase that raised the South Småland Peneplain to its present elevation and lead to re-exposure of sub-Cretaceous hilly relief is not resolved in the AFTA data. The results underline the importance of epeirogenic movements (both uplift and subsidence) in regions that are often considered as stable cratons (cf. Green et al., 2013). Green, P.F., Lidmar-Bergström, K., Japsen, P., Bonow, J.M., Chalmers, J.A., 2013. Stratigraphic landscape analysis, thermochronology and the

  17. Uncoupled vs. coupled thrust belt-foreland deformation: a model for northern Patagonia inferred from U-Th/He and apatite fission track dating

    Science.gov (United States)

    Savignano, Elisa; Mazzoli, Stefano; Zattin, Massimiliano; Gautheron, Cécile; Franchini, Marta

    2017-04-01

    The study of the Cretaceous - Cenozoic evolution of the Patagonian Andes represents a great opportunity to investigate the effects of coupling between deep lithospheric processes and near-surface deformation. Low-temperature thermochronological systems are ideally suited for detecting events involving rocks in the uppermost part of the crust because they record time and rates of cooling related to exhumation of the top few kilometers of the crust. The Patagonia region, although characterized by a general continuity of the Andean orogen along its strike, shows an appreciable internal tectonic segmentation (marked by a variable position of the magmatic arc and of the deformation front in the retroarc area) at various latitudes. This complex structural architecture has been interpreted as the result of different processes acting since the Late Cretaceous. The present-day configuration of the southern Andes is interpreted to have been controlled by alternating stages of flat- and steep-slab subduction, which produced shortening and upper plate extension episodes,, respectively. Furthermore, the deformation in this whole retroarc sector varied not only in time (i.e. with major 'cycles' of mountain building and orogenic collapse), but also in space, due to the variable transmission of horizontal compressive stress away from the orogen, that produced an irregular unroofing pattern. In this study, we have integrated field structural observations with new apatite (U-Th)/He data (AHe) and apatite fission-track (AFT) ages in the north Patagonia region (at latitudes between 40° and 44°S) in order to analyse and compare the exhumation patterns from the frontal part of the orogen and from the adjacent foreland sector, as well as to gain new insights into the timing and modes of coupling vs. uncoupling of the deformation between the northern Patagonian fold and thrust belt and its foreland. The obtained data indicate a markedly different unroofing pattern between the 'broken

  18. Influence of inherited structures on the growth of basement-cored ranges, basin inversion and foreland basin development in the Central Andes, from apatite fission-track and apatite Helium thermochronology.

    Science.gov (United States)

    Zapata, S.; Sobel, E. R.; Del Papa, C.; Jelinek, A. R.; Muruaga, C.

    2017-12-01

    The Central Andes in NW of Argentina is part of a long-lived subduction zone, active since the Paleozoic. This region experienced several tectonic cycles; each of which created an unique set of structures and may have reactivated preexisting structures. These inherited structures may exert a first-order control over the different foreland deformational styles observed along the strike in the Central Andes. Our study area is located between 26°S and 28°S on the transition between the broken foreland (Santa Barbara system), which expresses a combination of thin-skin and thick-skin styles, and the Sierras Pampeanas, which is deform in a thick-skin style. The Cumbres Calchaquies range and the associated Choromoro Basin are located in the northern part of the study area, and are the southern expression of the Santa Barbara system. Published thermochronology data suggest that the rocks from the basement experienced Late Cretaceous and Late Miocene exhumation; the associated sedimentary rocks within the Choromoro basin experienced Paleogene and Late Miocene deformational phases. In contrast, the Sierra Aconquija range, located immediately south on the transition to the Sierras Pampeanas (thick skin) foreland basin, exhibit larger amounts of Miocene exhumation and lack of Cretaceous exhumation; the associated sedimentary rocks from the Tucuman basin have not been deformed since the Cretaceous. Our goal is to understand the evolution of the structural blocks and the structures responsible for the along strike changes in foreland basin deformational styles and their relation with inherited structures from previous tectonic cycles. We are obtaining new apatite U-Th/He and fission track data to reconstruct the thermal history of the basement, accompanied by U-Pb geochronology and stratigraphy to constrain the evolution of the associated sedimentary basins. Preliminary results combined with published data suggest that inherited structures within the study area have evolved

  19. Dynamic of an intra-continental orogenic prism: thermo-chronologic (apatite fission tracks) and tectonic evolution of the axial zone and the piedmont of the west-central Pyrenees

    International Nuclear Information System (INIS)

    Meresse, F.

    2013-02-01

    This work illustrates the application of thermo chronology to the study of the following geologic issue: the tectonic evolution of the Pyrenean oncologic prism. Thermo-chronology gives information on the vertical movements at the scale of geological eras. Thermo-chronology is based on the following principle: the decay of a nucleus gives birth to a daughter nucleus. Above a specific temperature named closure temperature, the daughter element can diffuse outside the system while below the closure temperature, diffusion is not possible. Consequently thermo-chronology can be considered to date the moment when a mineral goes below a a specific closure temperature. Minerals have different closure temperatures and so by using a suite of thermo-chronometers on a single sample, its cooling path through the crust can be reconstructed. This work focuses on apatite fission track (AFT)analysis which is a low temperature thermo-chronometer. In apatites the temperature range between 60 and 120 Celsius degrees corresponds to the partial annealing zone. The spontaneous fission of one U 238 nucleus entails the formation of one fission track. The determination of the initial quantity of U 238 is based on the natural steady ratio U 238 /U 235 which equals 137.88. The initial quantity of U 235 is determined through the neutron irradiation of the sample. The knowledge of the initial quantity of U 238 and the number of tracks in the sample allows the dating of the sample. In this work we combine AFT thermo- chronology with a detailed structural analysis to describe vertical movements related to the thrusting system evolution, and to determine the influence of the latter on the sedimentation/burial/exhumation cycle of the syn-orogenic deposits of the southern fore-land basin

  20. Mid-miocene cooling in the northern Qilian Shan, northeastern margin of the Tibetan plateau, revealed by apatite fission-track and VR analysis

    International Nuclear Information System (INIS)

    George, A.D.; Wyrwoll, K.-H.; Jie, C.; Yanchou, L.

    1999-01-01

    Full text: Growth of the Tibetan Plateau along its northeastern margin by crustal shortening and thickening is linked to the Altyn Tagh Fault, a ∼1500 km long sinistral strike-slip fault which has played a significant role in accommodating the convergence of India and Eurasia. The NW-trending Qilian Shan (mountains) that mark the northeastern edge of the plateau rise nearly 5000 m above the adjacent Juice Basin of the Hexi Corridor. The Qilian Shan is a mid-Paleozoic orogenic suture belt composed of numerous thrust slices of deformed Lower Paleozoic (Cambrian-Silurian) metasedimentary and metavolcanic strata. The older Precambrian basement is also exposed in some thrust sheets, as are remnants of Upper Paleozoic-Jurassic strata. Cretaceous fluvial sandstones and conglomerates are locally preserved. The neighbouring Juice Basin contains a thick succession of Neogene-Quaternary fluvial strata (∼3.5 km thick) which unconformably overlies Lower Cretaceous rocks. Adjacent to the Qilian Shan, the oldest Neogene strata in the Juice Basin are Miocene in age overlain by more extensive Pliocene and Quaternary sediments, whereas basal Oligocene strata are exposed on the northern side of the basin. Neogene and Quaternary strata are being actively deformed by thrust-related folding along the margins and within the Jiuxi Basin. Apatite fission-track and vitrinite reflectance data were obtained from Precambrian to Tertiary outcrop samples from the northern Qilian Shan and Juice Basin to provide constraints on timing of exhumation and cooling. All the samples record multiple cooling episodes. Tertiary cooling from peak paleotemperatures (40-120 deg C) beginning sometime between 20 and 10 Ma (mid-Miocene) is common to all samples. This age is significantly older than previous models which proposed initiation of uplift in the Pliocene-Pleistocene, i.e., no older than 5-6 Ma. For any reasonable paleo-geothermal gradient, the degree of mid-Miocene cooling requires km

  1. Evolution of the South Atlantic passive continental margin and lithosphere dynamic movement in Southern Brazil derived from zircon and apatite (U-Th-Sm)/He and fission-track data

    Science.gov (United States)

    Krob, Florian; Stippich, Christian; Glasmacher, Ulrich A.; Hackspacher, Peter C.

    2016-04-01

    Passive continental margins are important geoarchives related to mantle dynamics, the breakup of continents, lithospheric dynamics, and other processes. The main concern yields the quantifying long-term lithospheric evolution of the continental margin between São Paulo and Laguna in southeastern Brazil since the Neoproterozoic. We put special emphasis on the reactivation of old fracture zones running into the continent and their constrains on the landscape evolution. In this contribution, we represent already consisting thermochronological data attained by fission-track and (U-Th-Sm)/He analysis on apatites and zircons. The zircon fission-track ages range between 108.4 (15.0) and 539.9 (68.4) Ma, the zircon (U-Th-Sm)/He ages between 72.9 (5.8) and 427.6 (1.8) Ma whereas the apatite fission-track ages range between 40.0 (5.3) and 134.7 (8.0) Ma, and the apatite (U-Th-Sm)/He ages between 32.1 (1.52) and 92.0 (1.86) Ma. These thermochronological ages from metamorphic, sedimentary and intrusive rocks show six distinct blocks (Laguna, Florianópolis, Curitiba, Ilha Comprida, Peruibe and Santos) with different evolution cut by old fracture zones. Furthermore, models of time-temperature evolution illustrate the differences in Pre- to post-rift exhumation histories of these blocks. The presented data will provide an insight into the complex exhumation history of the continental margin based on the existing literature data on the evolution of the Paraná basin in Brazil and the latest thermochronological data. We used the geological model of the Paraná basin supersequences (Rio Ivaí, Paraná, Gondwana I-III and Bauru) to remodel the subsidence and exhumation history of our consisting thermochronological sample data. First indications include a fast exhumation during the early Paleozoic, a slow shallow (northern blocks) to fast and deep (Laguna block) subduction from middle Paleozoic to Mesozoic time and a extremely fast exhumation during the opening of the South Atlantic

  2. The fission track method

    International Nuclear Information System (INIS)

    Hansen, K.

    1990-01-01

    During the last decade fission track (FT) analysis has evolved as an important tool in exploration for hydrocarbon resources. Most important is this method's ability to yield information about temperatures at different times (history), and thus relate oil generation and time independently of other maturity parameters. The purpose of this paper is to introduce the basics of the method and give an example from the author's studies. (AB) (14 refs.)

  3. Uplift along the Salt Lake sediment of the Wasatch fault from apatite and zircon fission track dating in the Little Cottonwood stock

    International Nuclear Information System (INIS)

    Kowallis, B.J.; Ferguson, J.; Jorgensen, G.J.

    1990-01-01

    Apatite from granite samples out of the Little Cottonwood stock of north-central Utah range in age from about 7 Ma at 1500 m elevation to about 11 Ma at 3500 m elevation and give an uplift rate of 0.68 mm yr -1 during this time period. Zircons from some of the same samples range in age from about 9 Ma at 1500 m elevation to 20 Ma at 3500 m, and probably represent an uplifted partial annealing zone. The uplift is associated with movement along the Wasatch fault which borders the stock on its western margin. The calculated uplift rates from the apatite ages in this study agree well with rates found by other workers along the central segments of the Wasatch fault using a variety of methods. (author)

  4. Using slope-area and apatite fission track analysis to decipher the rock uplift pattern of the Yumu Shan: New insights into the growth of the NE Tibetan Plateau

    Science.gov (United States)

    Wang, Yizhou; Zheng, Dewen; Pang, Jianzhang; Zhang, Huiping; Wang, Weitao; Yu, Jingxing; Zhang, Zhuqi; Zheng, Wenjun; Zhang, Peizhen; Li, Youjuan

    2018-05-01

    Studies have shown that the growth of the Qilian Shan, the northeastern margin of the Tibetan Plateau, started 10 Ma ago. However, when and how it expanded northwards is still under debate. Here we focus on the rock uplift pattern of the Yumu Shan, an active fault-related fold in the Hexi Corridor north to the Qilian Shan. Normalized channel steepness achieved from the analysis of river longitudinal profiles shows a spatially variant rock uplift pattern, with higher rates in the middle part and lower rates towards the west and east tips. The compression of the mountain is typically accommodated by fault-fold related shortening and vertical thickening. Apatite fission track thermochronology reveals that the growth of the Yumu Shan started 4 Ma ago, similar to the work on active tectonics. Combining the onset ages of the growth of the Qilian Shan (10 Ma), Laojunmiao anticline (3-4 Ma), Baiyanghe anticline (3-4 Ma), Wenshu Shan (4.5 Ma) and Heli Shan (2 Ma), we draw an conclusion that the NE margin of the Tibetan Plateau initiated growth in the mid-Miocene and expanded to the Hexi Corridor and to the south of the Alxa block in the early Pleistocene.

  5. Fission track imaging of the Australian continent

    International Nuclear Information System (INIS)

    Gleadow, A.; Kohn, B.; O'Sullivan, P.; Brown, R.; Gallagher, K.

    1999-01-01

    Full text: Techniques to reconstruct the thermal histories of rocks in the low-temperature environment of the upper crust have previously found important applications in such areas as sedimentary basin analysis, the evolution of convergent orogenic belts and studies of extensional tectonic environments. Increasingly large sets of thermochronology data are now becoming available on an even larger scale from the apatite fission-track system (for temperatures <∼110 deg C). Additional information is also now starting to emerge at even lower temperatures (<∼75 deg C) from the apatite (U-Th)/He system. The results from such systems can be used in novel ways to examine and visualise the evolution of the upper part of the continental crust. Quantitative modelling has brought a new dimension to this work and forward-modelling procedures are now well established which give 'best fit' thermal histories for temperatures less than about 110 deg C. In many cases the modelled thermal histories provide a proxy for rock transport towards the surface as overlying material is removed by denudation. Such information allows a reconstruction of the denudation history of the land surface. Applying these modelling procedures to large regional arrays of fission-track data means that the thermal history information can now be integrated with other regional data sets to provide an important new perspective on crustal and surface evolution. Apatite fission track analysis has now been completed on nearly 3000 surface outcrop samples across Australia under an AGCRC project to image the thermotectonic evolution of the exposed basement rocks of the continent. The samples analysed are mostly from rocks of broadly granitic composition and the apatites separated from these are overwhelmingly fluorapatites, which are consistent in their fission-track annealing properties with those on which the numerical annealing models are based. By interpolating the calculated thermal histories a series of

  6. The latest progress of fission track analysis

    International Nuclear Information System (INIS)

    Wang Shicheng

    1996-01-01

    Fission track analysis as a new nuclear track technique is based on fission track annealing in mineral and is used for oil and gas exploration successfully. The west part of China is the main exploration for oil and gas. The oil and gas basins there experienced much more complicated thermal history and higher paleotemperature. In order to apply fission track analysis to these basins, following work was be carried out: 1. The decomposition of grain age distribution of zircon fission tracks. 2. Study on thermal history of Ordos basin using zircon fission track analysis. 3. The fission track study on the Qiang Tang basin in tibet

  7. Damage morphology of Kr ion tracks in apatite: Dependence on dE/dX

    CERN Document Server

    Villa, F; Rebetez, M; Dubois, C; Chambaudet, A; Chevarier, A; Martin, P; Brossard, F; Blondiaux, G; Sauvage, T; Toulemonde, M

    1999-01-01

    With the aim of characterizing damage along nuclear tracks in apatite, Durango fluoroapatite monocrystals were irradiated under a high fluence sup 8 sup 6 Kr ion beam at the G.A.N.I.L. (Grand Accelerateur National d'Ions Lourds, Caen, France). The resulting irradiation damage was studied by associating CRBS spectrometry and chemical etching. By applying Poisson's law to the backscattering results, the nuclear track average effective radius R sub e was calculated for different steps along the ion path. On the other hand, the chemical etching experiments allowed us to deduce three different damaging morphologies in correspondence to the R sub e values. For the first time in apatite, it has been shown that a defect fragmentation produced along the ion paths may be detected by chemical etching. These results were also applied to fission tracks in order to quantify the damage rate and to describe the damage morphology evolution along fission fragment paths.

  8. Recent progress in fission track analysis and its applications in China

    International Nuclear Information System (INIS)

    Wang, S.C.; Kang, T.S.; Jing, G.R.

    1993-01-01

    Fission track analysis (FTA) has been developed and applied in China since 1985. Since then great efforts have been made on methodology and applications. In order to improve the accuracy of fission track dating, zeta calibration constants have been determined against NBS SRM 962 standard uranium glass and seven age standards. TINT method and silver coating were used to increase the density and contrast of confined spontaneous fission tracks on apatite. Based on the fanning model of fission track annealing for apatite presented by Laslett, G.M., a forward computer modeling of track shortening and age evolution was completed and an inverse method of modeling thermal histories from apatite fission track data is underway. Apatite fission track data (age and track length), zircon age and forward modeling method have been used to reveal thermal and tectonic histories of several sedimentary basins and of a collision zone in China. In this presentation some progress in methodology and application will be presented and discussed. (Author)

  9. Age of the Serra do Martins Formation, Borborema Plateau, northeastern Brazil: constraints from apatite and zircon fission track analysis; Idade da Formacao da Serra dos Martins, Planalto da Borborema, nordeste do Brasil: analise de tracos de fissao em apatia e zircao

    Energy Technology Data Exchange (ETDEWEB)

    Morais Neto, Joao Marinho de [PETROBRAS, Rio de Janeiro, RJ (Brazil). E e P. Gerencia de Interpretacao], e-mail: jmarinho@PETROBRAS.com.br; Green, Paul Frank [Geotrack International Pty. Ltd., Brunswick West, Victoria (Australia)], e-mail: mail@geotrack.com.au; Karner, Garry David [ExxonMobil Upstream Research Co., Houston TX (United States)], e-mail: garry.d.karner@exxonmobil.com; Alkmin, Fernando Flecha de [Universidade Federal de Ouro Preto (UFOP), MG (Brazil). Escola de Minas], e-mail: alkmin@degeo.ufop.br

    2007-11-15

    Results of apatite and zircon fission track analysis of samples from the Serra de Santana mesa provide quantitative constraints on the depositional age of the nonfossiliferous Serra do Martins Formation. This unit consists of sedimentary remnants preserved at high elevations on the Borborema Plateau and its distributions and age are considered important in understanding the geomorphological evolution and denudation history of northeastern Brazil following the early Cretaceous breakup. We also report apatite fission track results from post-rift units of the Potiguar Basin (Acu and Tibau formations). Apatite fission track analysis (AFTA) of samples from the Serra do Martins Formation suggests that they reached maximum paleotemperatures around 60 deg C, from which they began to cool some time between 30 and 0 Ma. Due to the high thermal gradients related to the prolonged Cenozoic volcanism in the study area, we hypothesize that the paleotemperatures modeled for those samples may be related dominantly to an anomalous heat flow, rather than to significant burial. Zircon fission track analysis (ZFTA) in two samples of the Serra do Martins Formation yields ages of 135 {+-}18 Ma and 165{+-}40 Ma, but both samples show a significant spread in the data, and the youngest population of grains in these samples are characterized by ages of 83{+-} Ma and 65{+-} Ma, respectively. As the AFTA data show that these ages have not been reset after deposition, the zircon fission track ages must represent inherited provenance ages, demonstrating that those sediments can be no older than Paleocene. Independent lithological observations provide additional support to reject a stratigraphic correlation between the Serra do Martins and Acu formations. Combining the AFTA and ZFTA results, and integrating available geological evidence, we suggest that the Serra do Martins Formation was deposited some time between 64 and 25 Ma (Paleocene-Oligocene). Modeled thermal history solutions from AFTA in

  10. Dating thermal events at Cerro Prieto using fission track annealing

    Energy Technology Data Exchange (ETDEWEB)

    Sanford, S.J.; Elders, W..

    1981-01-01

    Data from laboratory experiments and geologic fading studies were compiled from published sources to produce lines of iso-annealing for apatite in time-temperature space. Fission track ages were calculated for samples from two wells at Cerro Prieto, one with an apparently simple and one with an apparently complex thermal history. Temperatures were estimated by empirical vitrinite reflectance geothermometry, fluid inclusion homogenization and oxygen isotope equilibrium. These estimates were compared with logs of measured borehole temperatures.

  11. Fission - track age of the Marjalahti Pallasite

    International Nuclear Information System (INIS)

    Bondar, Yu.V.; Perelygin, V.P.

    2006-01-01

    Full text: Investigation of fossil charged-particle tracks in various mineral phases of extraterrestrial samples is a powerful method for research the early stages of the solar system. Over geological time, meteorites crystals have accumulated a record of tracks produced by heavily charged energetic particles from both internal (spontaneous fission of 238U and some other extinct isotopes) and external sources (galactic cosmic rays with Z>20). The fortunate fact that meteorite grains can accumulate latent and very long-lived tracks since soon after the end of nucleosynthesis in the solar nebula enables one to decode their radiation history and to detect any thermal events in the meteorite cosmic history by revealing these tracks through suitable etching procedures. Only a few minerals in meteorites (mainly phosphates) contain small amount of uranium; the fact that 238 U undergoes fission with fission-decay constant λ f ∼ 8.2x10 -17 yr -1 allows one to use this isotope as a chronometer. By measuring the U concentration in the crystals (by reactor irradiation) and the density of the spontaneous-fission tracks it is relatively easy to calculate the 'fission-track age' if 238 U is the main source of fission tracks. However the fission-track dating of extraterrestrial samples compared with the terrestrial ones has some peculiar features due to presence of a number of other potential track sources except the spontaneous fission of 238 U, such as the spontaneous fission of presently extinct 244 Pu, heavy nuclei of cosmic rays and induced fission by cosmic ray primaries. Only tracks from the spontaneous fission of U and Pu are suitable for fission-track dating. The competing effects of these fissioning elements, whose half-lives differ by a factor of ∼50, form a basis for a fission-track chronology for samples older than ∼ 4.0 Gyr. Over small intervals in time (∼ few x10 8 yr ) the track density from spontaneous fission of 238 U is nearly constant. However, the

  12. Is channeling of fission tracks taking place?

    CERN Document Server

    Yada, K

    1999-01-01

    A single crystal of natural zircon which is sliced to have (010) basal plane and thinned by ion thinning is electron microscopically observed after slow neutron irradiation to ascertain whether channeling of the nuclear fission fragments is taking place or not. A fairly large number of the induced fission tracks are recognized at low magnification images where a considerable number of them are parallel to low-index lattice planes such as 100, 001, 101, 301, 103 though their directions changed some time up to several degrees. High resolution images of fission tracks often show a variety of zigzag passing of the tracks along low-index lattice planes in atomistic level. The rate of the tracks which are parallel to these low-index lattice planes is fairly high as about 45%, which strongly suggests that channeling of the fission tracks is taking place.

  13. Fission-track evidence of tectonic evolution in the northwestern Qaidam Basin, China

    Science.gov (United States)

    Sun, Guo-Qiang; Liu, Wei-Ming; Guo, Jia-Jia; Wang, Ye-Tong

    2018-02-01

    Fission-track dating was conducted on zircons and apatites from 11 cores of the upper Xiaganchaigou Formation and lower Shangganchaigou Formation (northwestern Qaidam Basin). The obtained apatite fission-track age is 3.1-61.9 Ma, and the zircon fission-track age is 49.2-123.5 Ma. Although the average apatite age is consistent with ages predicted from the stratigraphy, nine of the 11 apatite fission-track ages have P(χ2) 5%, exhibiting consistent characteristics and indicating that zircons retain provenance age information after burial. From the zircon and apatite ages, the fission-track length distribution, and the geological setting, the northwestern Qaidam Basin has experienced two tectonothermal events since the Late Mesozoic, at 39.1 ± 9.3 to 133.7 ± 6.6 Ma and 1.2 ± 0.6 to 32.0 ± 3.0 Ma. The earlier (39.1-133.7 Ma) tectonothermal event resulted from the initial collision of the Indian and Eurasian plates. As a consequence of the collision, the Altyn Tagh fault, which forms the northwestern boundary of the Qaidam Basin, began to develop. Subsequently, uplift of the Altyn Tagh mountains began and the northwestern depression of the Qaidam Basin started to form. The later (1.2-32.0 Ma) tectonothermal event resulted from further collision of the Indian and Eurasian plates along the Yarlung Tsangpo suture zone. Strata in the Qaidam Basin were further deformed by transpression in this period and this period played a crucial role in petroleum accumulation.

  14. An improved technique for fission track dating

    International Nuclear Information System (INIS)

    Zhao Yunlong; Wu Zhaohui; Xia Yuliang

    1996-01-01

    The necessity of improving the fission track dating (FTD) technique both at home and abroad is illustrated. The ways of making such improvement are also proposed. It is suggested to calibrate the constant b value of the uranium standard glass by using the method of fission products activity. The 3 kinds of uranium standard glass which have been calibrated are NBS SRM962a, UB 1 and UB 2 . An established new method σ·Φ ρ d /b, to measure neutron fluence, avoids the influence of the varying neutron spectrum on measuring neutron fluence. The improved etching technique for fission tracks in zircon adopted a two-step method which includes the molten alkali system etching using NaOH + KOH and the mixed acid system etching using HNO 3 + HF; this technique results in adequate track etching, increased track clarity and less interference. In this way the intensity of tracks is authentically reflected. Dividing angular zone in accordance with the angular distribution of spontaneous fission track on the crystal surface of minerals to count the tracks and using the improved etching technique to remove the non-uniform angular distribution of spontaneous fission tracks in zircon, ensure the accuracy of tracks count. The improved FTD techniques were used to finish Laboratory Standardized Calibration. The tests using international FTD age standards samples have proved that above mentioned techniques are reliable and practical in obtaining the accurate FTD data. (8 tabs.; 3 figs.)

  15. Obsidian dating by fission track method

    International Nuclear Information System (INIS)

    Araya, A.M.O.

    1990-12-01

    The fission track method was employed to obtain the age of twelve obsidian sample from Ecuador. By using the plateau-age correction method, we obtained the true age of each sample and were able to identify four groups of ages in the studied area. Thereafter we studied the fading of fission tracks in two obsidian samples with different origins: Yanaurcu, Ecuador and Monte Arci, Italy. We constructed Arrhenius plots and calculated activation energies for both samples. The results from thermal annealing experiments were compared with theoretical curves obtained by integrating an equation proposed by Shukolyukov et al (1965). (author). 43 refs, 20 figs, 10 tabs

  16. Geological evolution of the southwestern part of the Veporic Unit (Western Carpathians) : Based on fission track and morphotectonic data

    NARCIS (Netherlands)

    Vojtko, Rastislav; Králiková, Silvia; Andriessen, Paul; Prokešová, Roberta; Minár, Jozef; Jeřábek, Petr

    2017-01-01

    Zircon and apatite fission track (FT) and morphotectonic analyses were applied in order to infer quantitative constraints on the Alpine morphotectonic evolution of the western part of the Southern Veporic Unit which is related to: (1) Eo-Alpine Cretaceous nappe stacking and metamorphism of the

  17. Contribution to statistics in fission track counting

    International Nuclear Information System (INIS)

    Bigazzi, G.; Bonadonna, F.; Neto, J.C.H.

    1986-01-01

    In order to test the new statistical model proposed in two papers by McGee, Johnson and Naeser for calculating the standard error in fission track dating, spontaneous and induced track counts from external detector method-EDM-or similar were simulated by random numbers, assuming that, for a given uranium content, fission tracks were spatially distributed according to Poisson distributions. By the results of such a simulation it can be concluded that: (1) In EDM, (1/nsub(s)+1/nsub(I)sup(1/2) represents a reliable evaluation of the relative standard error of rhosub(s)/rhosub(I)-ratio of spontaneous to induced track densities in a sample in which nsub(s) spontaneous and nsub(I) induced tracks were counted. (2) The new model confirms the validity of the above conclusion, by applying it to the spontaneous and induced track counts whose relative standard deviations of the means were evaluated by normal sampling statistics. Population method-PM-data were also simulated; (σ-bar' 2 sub(s)+σ-bar' 2 sub(I))sup(1/2), where σ-bar'sub(s) and σ-bar'sub(I) are the above relative standard deviations of the mean, offers a reliable evaluations of the uncertainty of rhosub(s)/rhosub(I) ratio for the simple cases analyzed in the present work. (author)

  18. Fission track dating: methodology and thermo-chronological applications in alpine and continental margin contexts

    International Nuclear Information System (INIS)

    Sabil, N.

    1995-06-01

    The fission track dating method has proved to be unique in thermo-chronology by its capability to describe the final phases of the cooling history and denudation of metamorphic massifs, like the thermal history of sedimentary formations or the dating of some volcanic materials. In this work we describe this method and present a series of new analytic techniques and calibrations which we realised in the aim of further use in geology. We discuss a few examples of such applications. In the french Occidental Alps, the analysis of fission track on apatite samples from the granites of the Sept Laux (Belledonne massif), in the Eau d' Olle valley, suggests that this method could bring a contribution to the actual discussion about the origin of some alpine valleys. The fission track method suggests that the opening of this valley could be the consequence of an active faulting from the middle Miocene until the present. The characterization of fluvial deposits through their detrital apatites fission tracks record could eventually be used to study river captures related to changes tectonic regimes. Therefore we studied the apatites of a paleo-delta located in the Isere middle valley at the sub-alpine 'sillon' level, and of two valleys, those of the Arc and of the Breda, located up the delta. The distribution of the fission track ages of those mineraIs has not confirmed a previously suggested model, which proposed that the studied paleo-delta could be associated with a paleo-Arc rather than a paleo-Breda. In the Moroccan Occidental Meseta, three granitic massifs located in the Rehamna have been selected for a thermo-chronological study. The analysis of the fission track in zircons and apatites of these granites recorded the thermo-tectonic events which have affected the Meseta ever since the opening of the Central Atlantic Ocean some 200 Ma ago. We show how a numerical simulation model recently (1994) proposed for the analysis of fission track in apatites allows us to specify

  19. High temperature annealing of fission tracks in fluorapatite, Santa Fe Springs oil field, Los Angeles Basin, California

    Science.gov (United States)

    Naeser, Nancy D.; Crowley, Kevin D.; McCulloh, Thane H.; Reaves, Chris M.; ,

    1990-01-01

    Annealing of fission tracks is a kinetic process dependent primarily on temperature and to a laser extent on time. Several kinetic models of apatite annealing have been proposed. The predictive capabilities of these models for long-term geologic annealing have been limited to qualitative or semiquantitative at best, because of uncertainties associated with (1) the extrapolation of laboratory observations to geologic conditions, (2) the thermal histories of field samples, and (3) to some extent, the effect of apatite composition on reported annealing temperatures. Thermal history in the Santa Fe Springs oil field, Los Angeles Basin, California, is constrained by an exceptionally well known burial history and present-day temperature gradient. Sediment burial histories are continuous and tightly constrained from about 9 Ma to present, with an important tie at 3.4 Ma. No surface erosion and virtually no uplift were recorded during or since deposition of these sediments, so the burial history is simple and uniquely defined. Temperature gradient (???40??C km-1) is well established from oil-field operations. Fission-track data from the Santa Fe Springs area should thus provide one critical field test of kinetic annealing models for apatite. Fission-track analysis has been performed on apatites from sandstones of Pliocene to Miocene age from a deep drill hole at Santa Fe Springs. Apatite composition, determined by electron microprobe, is fluorapatite [average composition (F1.78Cl0.01OH0.21)] with very low chlorine content [less than Durango apatite; sample means range from 0.0 to 0.04 Cl atoms, calculated on the basis of 26(O, F, Cl, OH)], suggesting that the apatite is not unusually resistant to annealing. Fission tracks are preserved in these apatites at exceptionally high present-day temperatures. Track loss is not complete until temperatures reach the extreme of 167-178??C (at 3795-4090 m depth). The temperature-time annealing relationships indicated by the new data

  20. A numerical model for the thermal history of rocks based on confined horizontal fission tracks

    DEFF Research Database (Denmark)

    Jensen, Peter Klint; Hansen, Kirsten; Kunzendorf, Helmar

    1992-01-01

    A numerical model for determination of the thermal history of rocks is presented. It is shown that the thermal history may be uniquely determined as a piece-by-piece linear function on the basis of etched confined, horizontal fission track length distributions, their surface densities...... measured in transmitted light are biased favouring short tracks compared with measurements in reflected light. Testing of the model is performed on apatites from a tuffaceous sandstone from Bornholm (Denmark) yielding an estimate of the thermal history for the period of about 280 Ma back in time....

  1. A numerical model for the thermal history of rocks based on confined horizontal fission tracks

    International Nuclear Information System (INIS)

    Jensen, P.K.; Kunzendorf, Helmar; Hansen, Kirsten

    1992-01-01

    A numerical model for determination of the thermal history of rocks is presented. It is shown that the thermal history may be uniquely determined as a piece-by-piece linear function on the basis of etched confined, horizontal fission track length distributions, their surface densities, and the uranium content. The initial track length distribution is taken into account. A relation between the measured track length distribution and age is given which includes correction for partial annealing. The annealing model used is the fanning Arrhenius plot. It is shown that track length distributions measured in transmitted light are biased favouring short tracks compared with measurements in reflected light. Testing of the model is performed on apatites from a tuffaceous sandstone from Bornholm (Denmark) yielding an estimate of the thermal history for the period of about 280 Ma back in time. (author)

  2. Fission-track evidence of tectonic evolution in the northwestern ...

    Indian Academy of Sciences (India)

    Guo-Qiang Sun

    2018-02-14

    Feb 14, 2018 ... Mesozoic and Cenozoic tectonics of the northern edge of the Tibetan Plateau: Fission-track constraints; Tectono- phys. S1–2 111–134. Kang T S and Wang S C 1991 Fission track – a method in geothermal history research; Science Press, Beijing. Lai S C, Deng J F and Zhao H L 1996 Volcanism and tec-.

  3. Neutron detection methods based on fission fragment track counting

    International Nuclear Information System (INIS)

    Posta, S.

    2004-12-01

    The report deals with the development and application of a simple computer-controlled videomicroscope for fission fragment track counting. The principle of the SSFTD (Solid State Fission Track Detector) method, development of image processing methods, and track counting principles are outlined. Focus is on the application of the method to neutron flux density and fluence determination in reactor dosimetry. The procedures developed were applied to neutron parameter measurements in a VVER-1000 mockup in the LR-0 research reactor. (author)

  4. Provenance and post-depositional low-temperature evolution of the James Ross Basin sedimentary rocks (Antarctic Peninsula) based on fission track analysis

    Czech Academy of Sciences Publication Activity Database

    Svojtka, Martin; Nývlt, D.; Murakami, Masaki; Vávrová, J.; Filip, Jiří; Mixa, P.

    2009-01-01

    Roč. 21, č. 6 (2009), s. 593-607 ISSN 0954-1020 R&D Projects: GA MŠk 1K05030 Institutional research plan: CEZ:AV0Z30130516 Keywords : James Ross Island * Seymour Island * Cretaceous–Palaeogene succession * fission track dating * zircon * apatite Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.496, year: 2009

  5. Uranium fission track length distribution modelling for retracing chronothermometrical history of minerals

    International Nuclear Information System (INIS)

    Rebetez, M.

    1987-01-01

    Spontaneous fission of uranium 238 isotope contained in certain minerals creates damage zones called latent tracks, that can be etched chemically. The observation of these etched tracks and the measurement of their characteristics using an optical microscope are the basis of several applications in the domain of the earth sciences. First, the determination of their densities permits dating a mineral and establishing uranium mapping of rocks. Second, the measurement of their lengths can be a good source of information for retracing the thermal and tectonic history of the sample. The study of the partial annealing of tracks in apatite appears to be the ideal indicator for the evaluation of petroleum potential of a sedimentary basin. To allow the development of this application, it is necessary to devise a theoretical model of track length distributions. The model which is proposed takes into account the most realistic hypotheses concerning registration, etching and observation of tracks. The characteristics of surface tracks (projected lengths, depths, inclination angles, real lengths) and confined tracks (Track IN Track and Track IN Cleavage) are calculated. Surface tracks and confined tracks are perfectly complementary for chrono-thermometric interpretation of complex geological histories. The method is applied to the case of two samples with different tectonic history, issued from the cretaceous alcalin magmatism from the Pyrenees (Bilbao, Spain). A graphic method of distribution deconvolution is proposed. Finally, the uranium migration, depending on the hydrothermal alteration, is studied on the granite from Auriat (France) [fr

  6. Xe- and U-tracks in apatite and muscovite near the etching threshold

    Energy Technology Data Exchange (ETDEWEB)

    Wauschkuhn, Bastian, E-mail: wauschku@geo.tu-freiberg.de [Geologie, Technische Universität Bergakademie Freiberg (Germany); Jonckheere, Raymond [Geologie, Technische Universität Bergakademie Freiberg (Germany); Mineralogie en Petrologie, Geologie en Bodemkunde, Universiteit Gent (Belgium); Ratschbacher, Lothar [Geologie, Technische Universität Bergakademie Freiberg (Germany)

    2015-01-15

    Ion irradiation of a wedge-shaped Durango apatite backed by a mica detector allows investigating ion track ranges and etching properties at different points along the tracks. Transmission profiles obtained by irradiation with 2 × 10{sup 6} cm{sup −2} 11.1 MeV/amu {sup 132}Xe and 2 × 10{sup 6} cm{sup −2} 11.1 MeV/amu {sup 238}U parallel to the apatite c-axis correspond to ranges calculated with SRIM (Xe: 76.3 μm; U: 81.1 μm). However, the measured profiles show much greater etchable track-length variations than the calculated longitudinal straggles. The probable cause is that the length deficit exhibits significant variation from track to track. The measured length deficit in muscovite is in agreement with most existing data. In contrast, the length deficit in apatite appears to be close to zero, which is in conflict with all earlier estimates. This probably results from the etching properties of the apatite basal face, which permit surface-assisted sub-threshold etching of track sections in the nuclear stopping regime. These sections are not accessible from the opposite direction, i.e. by etching towards the endpoint of the tracks or in the direction of the ion beam. This conclusion is supported by the fact that linear dislocations are revealed in apatite basal faces and by the observation of imperfect etch pits that are separated from the etched ion track channel by a section that appears unetched under the microscope.

  7. Rapid Late Miocene Exhumation in the Central Alps, Constrained by (U-Th)/He and Fission Track Thermochronology

    Science.gov (United States)

    Aramowicz, A.; Cosca, M.; Stockli, D.; Farley, K.; Seward, D.

    2007-12-01

    Zircon and apatite (U-Th)/He thermochronological data together with apatite fission track analyses are used to explore uplift and exhumation of the western part of the Aar massif in the central Swiss Alps. A total of 27 samples were collected from the surface and underground, from the world's deepest tunnel (Loetschberg NEAT), with an overall elevation difference of almost 2500 m. Zircon (U-Th)/He ages range from 5.5 to 7.6 Ma, apatite fission track ages range from 5.7 to 6.5 Ma and apatite (U-Th)/He ages range from 3 to 5.5 Ma. All zircon age-elevation profiles from three traverses, show distinct brakes in slope that mark a drastic, 10-fold acceleration of exhumation at 6 ± 0.5 Ma ago (from 0.3 km/Ma to 3 km/Ma). The trend of fast exhumation appears to be maintained in the apatite fission track data while apatite (U-Th)/He ages suggest a return to moderate, apparent exhumation rates of 0.5 km/Ma. We propose that the accelerated exhumation may be linked to the Messinian desiccation of the Mediterranean. During that event, Mediterranean sea level dropped locally by as much as 3 km which accelerated erosion in the Alps. Consequently, the erosion in the Alps must have increased. If wedge mechanics are considered, the increased erosional flux reduced the active width of the orogen and, during latest convergence, deformation focused in the internal parts of the Alps, i.e. Aar massif. This interpretation implies a strong and prompt feedback between external forcing and tectonic response of the orogen. The slower exhumation rate apparent from the apatite (U-Th)/He data may reflect a decline in deformation. Alternatively, due to its low closure temperature, this system is prone to resetting by heat advected through hydrothermal circulation. This scenario needs further investigation but abundant hot-water (ca. 50 °C) discharge in the sampled tunnel is not uncommon.

  8. Uranium Distribution in Some Carbonate and Phosphate Rocks Using Fission Track Registration

    International Nuclear Information System (INIS)

    Jubeli, Y.M

    1998-01-01

    An integrated geochemical and petrological procedure was used to investigate the controls on uranium distribution in some carbonate, phosphate and other sedimentary rocks. The fission track registration technique, along with geochemical analysis of uranium was applied to effectively locate, evaluate and identify the patterns of uranium distribution within these rocks and their constituents. Differences in the density of the tracks were found in isotropic and anisotropic grains of coprolite, ovulite, glauconite, calcite and cellophane, as well as, apatite and other phosphatic particles. The variations in uranium concentrations seem to be related to more than one type of uranium incorporation mechanism, particularly caused by syngenetic and epigenetic processes. It was concluded that the obtained variations in U content are due to a combination of sedimentological, textural, geochemical, physiochemical and a few other controls and mechanisms

  9. Comparison through fission-track analysis of portions of Australia and Antarctica adjacent prior to continental drift

    International Nuclear Information System (INIS)

    Stump, E.; Fitzgerald, P.G.

    1990-01-01

    Australia and Antarctica have been reconstructed by the matching of three terranes in western Victoria with three terranes in northern Victoria Land. Apparent fission-track ages from granitic rocks of these matched regions are compared. In western Victoria, Australia, data reflect a history of slow cooling following intrusion in early to middle Paleozoic time. In northern Victoria Land, Antarctica, a complex history of cooling and uplift is indicated, with uplift of the present-day mountains commencing approximately 50 Ma. Fission tracks in apatites from most samples from northern Victoria Land were completely re-set to zero by the thermal effects of Jurassic tholeiitic magmatism. Apatite in three samples however, predate the Jurassic and were only partially re-set by this event. Apparent sphene fission-track ages indicate that the three terranes in northern Victoria Land have shared a common thermal history since the Devonian. With the exception of one small area in western Victoria, neither western Victoria nor northern Victoria Land data show a clear influence of rifting and breakup in the late Cretaceous. Overall, the data indicate that once the breakup of Australia and Antarctica had occurred, their thermal and tectonic histories evolved independently along differing paths. (author)

  10. Chrono-thermométrie par traces de fission : une perspective nouvelle pour la prospection pétrolière Chronothermometry by Fission-Track Dating: New Means for Petroleum Prospection

    Directory of Open Access Journals (Sweden)

    Storzer D.

    2006-11-01

    Full Text Available La propriété caractéristique des traces de fission d'enregistrer les paléotempératures offre la possibilité unique de caler des événements thermiques dans leur contexte géologique et donc de modéliser quantitativement les histoires thermiques des roches. Le thermomètre traces de fission-apatite enregistre les paléo-températures dans un intervalle compris entre 30 et 170°C, domaine qui inclut les températures généralement retenues pour la genèse optimale des hydrocarbures liquides. La formation, la maturation et la destruction des hydrocarbures, de la même façon que la guérison des traces latentes, sont fonction des deux paramètres temps et températures; en conséquence, l'étude détaillée de l'effacement progressif des traces latentes fossiles dans les apatites en fonction de leur profondeur dans un puits, conduit à des indications précises sur les variations de la température en fonction du temps à l'intérieur de la fenêtre à huile. Ces deux informations sont obtenues en combinant la datation traces de fission-isochrone et les analyses de longueurs des traces de fission. Le potentiel de la méthode des traces de fission dans son application à la reconstitution de l'histoire thermique des bassins sédimentaires est illustré à partir de l'analyse d'apatites détritiques provenant des bassins intérieur et côtier du Gabon d'une part et du bassin d'Otway en Australie du Sud d'autre part. The characteristic property of fission tracks to record paleotemperatures provides a unique possibility of setting thermal events in their geological context and hence of quantitatively modeling the thermal histories of rocks. The fission track apatite-thermometer records paleotemperatures in the interval between 30 and 170°C, a range that includes the temperatures generally considered to be required for the optimum formation of liquid hydrocarbons. The formation, maturation and destruction of hydrocarbons, as well as the

  11. Characteristics of diallyl phthalate resin as a fission track detector

    CERN Document Server

    Tsuruta, T

    1999-01-01

    Diallyl phthalate (DAP) resin plates were irradiated with fission fragments, and then etched in aqueous solution of KOH. Etched tracks were observed and counted by using an optical microscope. The detection efficiency of fission fragments was about 100% for both perpendicular and random incidence. DAP plates were insensitive to alpha particles and fast neutrons. These characteristics are suitable for detecting selected fission fragments, which coexist with alpha particles or fast neutrons. DAP plates are valuable for quantitative analysis of fissionable materials and neutron dosimetry. DAP and allyl diglycol carbonate (CR-39) were formed into copolymers in various ratios. The copolymers showed intermediate characteristics between DAP and CR-39. The fabrication of the copolymers made it possible to control the discrimination level for detection of heavy charged particles.

  12. Fission track dating of mesozoic sandstones and its tectonic significance in the Eastern Sichuan Basin, China

    International Nuclear Information System (INIS)

    Shen Chuanbo; Mei Lianfu; Xu Sihuang

    2009-01-01

    To establish the tectonic evolution of the eastern Sichuan basin, apatite fission track dating and time-temperature thermal history modeling were carried to analyze on 11 samples collected from Jurassic sandstones. The results indicate that the cooling and exhumation process of the eastern Sichuan basin can be divided into three stages since Cretaceous, (1) a rapid cooling phase between ∼100 and ∼70 Ma, (2) following by a period of relative thermal stability phase between ∼70 and ∼15 Ma, (3) and then a new rapid cooling stage after ∼15 Ma. Two rapid cooling events imply that the eastern Sichuan basin once underwent two tectonic movements since Cretaceous. The first rapid cooling is associated with Mesozoic tectonic reactivation beginning at 100 Ma, which result in folds and faults of the eastern Sichuan basin. The second tectonic movement occurred at 15 Ma, which is related to denudation by compression resulting from the eastward growth of Tibetan plateau uplift.

  13. Fission track dating evidence on tectonic activities of northern Himalaya block

    International Nuclear Information System (INIS)

    Yuan Wanming; Wang Shicheng; Wang Lanfen

    2002-01-01

    Fission track ages (FTA) of 4 apatite samples collected from Langkazi to Yarlung Zangbo thrust zone range between 13.6 and 17.2 Ma, reflecting the time of continent-continent collision and differing from previous data. The negative correlation between the FTA and sample elevations shows there was rapid uplifting during the continent-continent collision with uplifting rate of 176 m/Ma. Denudation degree, denudation rate and cooling rate were ∼2.9 km, 213 m/Ma and 7 degree C/Ma respectively since 13.6 Ma. FTA of 3 zircon samples are different significantly and have x 2 test value of < 0.1%, confirming the orogeny within continent went under low temperature

  14. The changing face of fission track dating: recent advances

    International Nuclear Information System (INIS)

    Green, P.F.; Duddy, I.R.; Gleadow, A.J.W.; Laslett, G.M.; Hegarty, K.A.; Lovering, J.F.

    1985-01-01

    Fission Track Dating has undergone something of a renaissance in recent years. What began as a rather unreliable method of geochronology has now become a rigorous and dependable means of measuring not only geological time but also paleotemperatures. Developments such as the zeta calibration technique, rigorous satistical data analysis, investigation of confined track lengths and detailed studies of annealing behaviour have all contributed to advances in the technique

  15. Influence of the cosmic-ray induced fission tracks on the fission track of extraterrestric minerals via the 238U spontaneous fission

    International Nuclear Information System (INIS)

    Damm, G.; Thiel, K.

    1977-01-01

    The age determined by counting fission tracks of lunar and meteorite materials is obviously falsified by additional fission track parts not to be accounted for by the spontaneous fission of uranium 238. For this p and n induced fissions of U, Th and other hreavy elements through the cosmic radiation come into consideration. In order to determine the possible part of such interference factors, a simulation experiment at the proton synchrocycloton (CERN, Geneva) has been carried out and independently of this, the production rates for the p and n induced U, Th, Bi, Pb and Au in the surface-near regolith layers of the moon were calculated. It could be seen that the irradiation age as well as the spacial distribution of the heavy metals in the samples to be dated must be considered. (RB) [de

  16. Using U-Pb apatite thermochronology to track the structural evolution of granitoid-orthogneiss domes from the Archean Pilbara craton

    Science.gov (United States)

    MacLennan, S. A.; Schoene, B.

    2017-12-01

    Granitoid-orthogneiss domes are an important component of all Archean crustal terranes. The Eastern Pilbara craton contains well-preserved examples of Mesoarchean granitoid-orthogneiss domes whose formation has been interpreted by many within a non-plate tectonic paradigm that hinges upon hotter crustal geotherms that drive partial convective overturn of the crust. This model makes predictions for the temperature-time histories of the domes that can be tested by high-temperature thermochronometry. We use U-Pb thermochronmetry in apatite, which is sensitive to mid crustal temperatures ( 400°C), and thus can track exhumation of gneiss domes from the lower to upper crust. These processes are not recorded in geochronometers (e.g., U-Pb zircon) or low temperature thermochronometers (e.g., U/Th-He, apatite fission track). The convective overturn model for the development of these domes predicts that exhumation of the granitoid ( 3.25 Ga) -orthogneiss (3.45 Ga) domes into the upper crust occurred rapidly (100 Ma after emplacement, followed by exhumation. A craton-wide deformational episode occurs at 3.0 Ga, but is poorly resolved in the eastern Pilbara craton. Our ca. 3.0 Ga apatite dates indicate that this period also drove structural modification in this area. When combined, these data indicate that the eastern Pilbara craton experience a ca. 400 Myr history of intrusion, deformation, and exhumation that resulted in the present crustal architecture, and highlight the utility of U-Pb in apatite as a tool to resolve tectonic histories by constraining the timing of exhumation or emplacement of material into the upper crust, and has wide applications to cratonic or orogenic studies.

  17. p- and n-induced U-fission tracks as possible error sources in the fission track dating of extraterrestric samples

    International Nuclear Information System (INIS)

    Thiel, K.

    1975-01-01

    Using the fission track dating method by means of uranium fission tracks in meteorites and moon samples (according to the successful Apollo and Luna missions), special problems arise, as the samples frequently have a very great age and were subjected to the inmediate effect of primary cosmic radiation. To determine the share of induced fission tracks, an extended 'cosmic ray' simulation experiment was carried out on the p-synchrocyclotron in CERN, Geneva; the performance and results of the test with the proton flux and U fission track measurements are dealt with in detail. (HK/LH) [de

  18. Fission-track constraints on the thermal and tectonic evolution of the Apuseni Mountains (Romania)

    Science.gov (United States)

    Kounov, Alexandre; Schmid, Stefan M.

    2013-01-01

    New zircon and apatite fission-track (FT) data, including apatite thermal modelling, are combined with an extensive literature survey and reconnaissance-type structural fieldwork in the Eastern Apuseni Mountains. This leads to a better understanding of the complex structural and thermal history of a key area at the boundary between two megatectonic units in the Balkan peninsula, namely the Tisza and Dacia Mega-Units. Following Late Jurassic obduction of the Transylvanian ophiolites onto a part of the Dacia Mega-Unit, that is, the Biharia nappe system, both units were buried to a minimum of 8 km during late Early Cretaceous times when these units were underthrust below the Tisza Mega-Unit consisting of the present-day Codru and Bihor nappe systems. Tisza formed the upper plate during Early Cretaceous (`Austrian') east-facing orogeny. Turonian to Campanian zircon FT cooling ages (95-71 Ma) from the Bihor and Codru nappe systems and the Biharia and Baia de Arieş nappes (at present the structurally lowest part of the Dacia Mega-Unit) record exhumation that immediately followed a second Cretaceous-age (i.e. Turonian) orogenic event. Thrusting during this overprinting event was NW-facing and led to the overall geometry of the present-day nappe stack in the Apuseni Mountains. Zircon FT ages, combined with thermal modelling of the apatite FT data, show relatively rapid post-tectonic cooling induced by a third shortening pulse during the latest Cretaceous (`Laramian' phase), followed by slower cooling across the 120°-60 °C temperature interval during latest Cretaceous to earliest Paleogene times (75-60 Ma). Cenozoic-age slow cooling (60-40 Ma) was probably related to erosional denudation postdating `Laramian' large-scale updoming.

  19. A new look at statistics in fission-track dating

    International Nuclear Information System (INIS)

    Green, P.F.

    1981-01-01

    Poissonian errors, as routinely applied in fission-track dating, represent a limiting case, which may not always be attainable in practice. Other experimental factors may introduce additional non-Poissonian errors, which must be taken into account. In the population method, sampling of non-homogeneous uranium distributions introduces experimental error. In the external detector method (EDM), many factors exist to introduce such error. Simply quoting total numbers of spontaneous and induced fission tracks obtained by the EDM may disguise the possible influence of experimental variation. The present work concentrates on the EDM, and describes a test which has recently been proposed to detect the presence of experimental error in EDM analyses. The question of an alternative analysis for cases where such error is present is also considered. A method of presenting EDM data is suggested, which allows assessment of the importance of experimental errors. (author)

  20. Liquid nitrogen enhancement of partially annealed fission tracks in glass

    International Nuclear Information System (INIS)

    Pilione, L.J.; Gold, D.P.

    1976-01-01

    It is known that the number density of fission tracks in solids is reduced if the sample is heated before chemical etching, and the effect of annealing must be allowed for before an age can be assigned to the sample. The extent of annealing can be determined by measuring the reduction of track parameters (diameter and/or length) and comparison with unannealed tracks. Correct ages can be obtained by careful calibration studies of track density reduction against track diameter or length reduction at different annealing temperatures and times. For crystallised minerals, however, the resulting correction techniques are not generally valid. In the experimental work described glass samples were partially annealed and then immersed in liquid N 2 for various periods, and it was shown that the properties of the glass and the track parameters could be altered so as to observe tracks that would normally be erased by annealing. The results of track density measurements against liquid N 2 immersion times are shown graphically. A gain of about 40% was achieved after 760 hours immersion time. The size of the tracks was not noticeably affected by the immersion. It was thought that thermal shock might be the cause of the track enhancement, but it was found that repeated immersion for about 2 hours did not lead to an increase in track density. Other studies suggest that the mechanism that erases the tracks through annealing may be partially reversed when the temperature of the sample is significantly lowered for a sufficient length of time. Further work is under way to find whether or not the process of enhancement is a reversal of the annealing process. Similar enhancement effects using liquid N 2 have been observed for d-particle tracks in polycarbonate detectors. (U.K.)

  1. Simulated fissioning of uranium and testing of the fission-track dating method

    Science.gov (United States)

    McGee, V.E.; Johnson, N.M.; Naeser, C.W.

    1985-01-01

    A computer program (FTD-SIM) faithfully simulates the fissioning of 238U with time and 235U with neutron dose. The simulation is based on first principles of physics where the fissioning of 238U with the flux of time is described by Ns = ??f 238Ut and the fissioning of 235U with the fluence of neutrons is described by Ni = ??235U??. The Poisson law is used to set the stochastic variation of fissioning within the uranium population. The life history of a given crystal can thus be traced under an infinite variety of age and irradiation conditions. A single dating attempt or up to 500 dating attempts on a given crystal population can be simulated by specifying the age of the crystal population, the size and variation in the areas to be counted, the amount and distribution of uranium, the neutron dose to be used and its variation, and the desired ratio of 238U to 235U. A variety of probability distributions can be applied to uranium and counting-area. The Price and Walker age equation is used to estimate age. The output of FTD-SIM includes the tabulated results of each individual dating attempt (sample) on demand and/or the summary statistics and histograms for multiple dating attempts (samples) including the sampling age. An analysis of the results from FTD-SIM shows that: (1) The external detector method is intrinsically more precise than the population method. (2) For the external detector method a correlation between spontaneous track count, Ns, and induced track count, Ni, results when the population of grains has a stochastic uranium content and/or when the counting areas between grains are stochastic. For the population method no correlation can exist. (3) In the external detector method the sampling distribution of age is independent of the number of grains counted. In the population method the sampling distribution of age is highly dependent on the number of grains counted. (4) Grains with zero-track counts, either in Ns or Ni, are in integral part of

  2. Thorium determination in water and biological materials by fission track

    International Nuclear Information System (INIS)

    Melo Ferreira, A.C. de.

    1989-01-01

    As a segment of a research programme on the study of bioaccumulation of radionuclides, in animals and vegetables from Morro do Ferro, Pocos de Caldas, MG, a fission track method for the determination of low levels of thorium in environmental samples was developed as an alternative for alpha spectroscopy. The study was carried out in early alpha spectroscopy samples, containing high levels of 228 Th activity, which makes difficult the 232 Th determination. A dry way method for thorium evaluation was developed. Pieces of membrane filters, containing La F 3 (Th), coupled to Makrofol detectors, were irradiated in the core of a research reactor, IEA-R1 (IPEN). (author)

  3. Age and significance of core complex formation in a very curved orogen: Evidence from fission track studies in the South Carpathians (Romania)

    Science.gov (United States)

    Fügenschuh, B.; Schmid, S. M.

    2005-07-01

    Twenty-four new zircon and apatite fission track ages from the Getic and Danubian nappes in the South Carpathians are discussed in the light of a compilation of published fission track data. A total of 101 fission track ages indicates that the Getic nappes are generally characterized by Cretaceous zircon and apatite fission track ages, indicating cooling to near-surface temperatures of these units immediately following Late Cretaceous orogeny. The age distribution of the Danubian nappes, presently outcropping in the Danubian window below the Getic nappes, depends on the position with respect to the Cerna-Jiu fault. Eocene and Oligocene zircon and apatite central ages from the part of the Danubian core complex situated southeast of this fault monitor mid-Tertiary tectonic exhumation in the footwall of the Getic detachment, while zircon fission track data from northwest of this fault indicate that slow cooling started during the Latest Cretaceous. The change from extension (Getic detachment) to strike-slip dominated tectonics along the curved Cerna-Jiu fault allowed for further exhumation on the concave side of this strike-slip fault, while exhumation ceased on the convex side. The available fission track data consistently indicate that the change to fast cooling associated with tectonic denudation by core complex formation did not occur before Late Eocene times, i.e. long after the cessation of Late Cretaceous thrusting. Core complex formation in the Danubian window is related to a larger-scale scenario that is characterized by the NNW-directed translation, followed by a 90° clockwise rotation of the Tisza-Dacia "block" due to roll-back of the Carpathian embayment. This led to a complex pattern of strain partitioning within the Tisza-Dacia "block" adjacent to the western tip of the rigid Moesian platform. Our results suggest that the invasion of these southernmost parts of Tisza-Dacia started before the Late Eocene, i.e. significantly before the onset of Miocene

  4. Dating by fission tracks in archaeology. 1. Principles and experimental methods

    International Nuclear Information System (INIS)

    Poupeau, G.; Zuleta, E.

    1984-01-01

    The principles of dating method by uranium fission tracks are shortly exposed. The conditions of application to the archaeology are discussed, in particular for the volcanic glasses, where the fossil fission tracks are often affected of a beginning of effacement. (L.C.) [pt

  5. Cretaceous—Quaternary tectonic evolution of the Tatra Mts (Western Carpathians: constraints from structural, sedimentary, geomorphological, and fission track data

    Directory of Open Access Journals (Sweden)

    Králiková Silvia

    2014-08-01

    Full Text Available The Tatra Mts area, located in the northernmost part of Central Western Carpathians on the border between Slovakia and Poland, underwent a complex Alpine tectonic evolution. This study integrates structural, sedimentary, and geomorphological data combined with fission track data from the Variscan granite rocks to discuss the Cretaceous to Quaternary tectonic and landscape evolution of the Tatra Mts. The presented data can be correlated with five principal tectonic stages (TS, including neotectonics. TS-1 (~95-80 Ma is related to mid-Cretaceous nappe stacking when the Tatric Unit was overlain by Mesozoic sequences of the Fatric and Hronic Nappes. After nappe stacking the Tatric crystalline basement was exhumed (and cooled in response to the Late Cretaceous/Paleogene orogenic collapse followed by orogen-parallel extension. This is supported by 70 to 60 Ma old zircon fission track ages. Extensional tectonics were replaced by transpression to transtension during the Late Paleocene to Eocene (TS-2; ~80-45 Ma. TS-3 (~45-20 Ma is documented by thick Oligocene-lowermost Miocene sediments of the Central Carpathian Paleogene Basin which kept the underlying Tatric crystalline basement at elevated temperatures (ca. > 120 °C and < 200 °C. The TS-4 (~20-7 Ma is linked to slow Miocene exhumation rate of the Tatric crystalline basement, as it is indicated by apatite fission track data of 9-12 Ma. The final shaping of the Tatra Mts has been linked to accelerated tectonic activity since the Pliocene (TS-5; ~7-0 Ma.

  6. New fission-track age constraints on the exhumation of the central Santander Massif: Implications for the tectonic evolution of the Northern Andes, Colombia

    Science.gov (United States)

    Amaya, Sergio; Zuluaga, Carlos Augusto; Bernet, Matthias

    2017-06-01

    The Late Cretaceous to late Neogene exhumation history of the central Santander Massif in the Northern Andes of Colombia is controlled by the geodynamic interactions between the Caribbean, South American and Nazca plates, as well as the Neogene collision and accretion of the Panama arc. Slab-breakoff of the Caribbean plate, with the tip of the slab tear presently being located beneath Bucaramanga, and the east-west oriented Caldas tear are the main structures relating seismic activity and Late Miocene to Pleistocene magmatic/hydrothermal activity and associated gold mineralization in the central Santander Massif. Here we present new apatite (AFT) and zircon fission-track (ZFT) data from 18 samples collected along two profiles in the California-Vetas block (including the Rio Charta), to the south of the Rio Charta fault, and from Bucaramanga to Picacho on the western flank of the central Santander Massif. The fission-track data are used for time-temperature history modelling and for estimating long-term average exhumation rates. The California-Vetas block in the central Santander Massif to the north of the Rio Charta fault cooled rapidly at a rate of about 24 °C/Myr between 10 and 5 Ma. Fast cooling was not related to post-magmatic cooling or hydrothermal activity, but rather to exhumation, with rates based on apatite fission-track cooling ages on the order of 0.3-0.4 km/Myr. However, long-term average exhumation rates since the Late Cretaceous, based on zircon fission-track data, were only on the order of 0.1-0.2 km/Myr. Our data indicate that next to the Rio Charta fault also the Surata fault contributed to the exhumation of the California-Vetas block. The western flank of the central Santander Massif, shows a more complete thermal history along the Bucaramanga-Picacho profile, with the exposure of an exhumed zircon fission-track partial annealing zone. Thermal history modelling of zircon fission-track data of this profile shows that after burial and heating from

  7. Dating of zircons by the fission track method

    International Nuclear Information System (INIS)

    Tenorio Hernandez, L.M.

    1992-01-01

    This work describes the methodology to date zircons by the Fission Track Method. A brief discussion is made of the physical principles of the method, physical properties of zircons and the geochemical properties of uranium. When starting with a hand sample, a mineral separation is required; to do this the following steps are needed: crushing and sieving of the sample, washing and drying, magnetic separation, heavy liquid separation (Bromoform 2.89 g/cm 3 , Diyodomethane = 3.31 g/cm 3 ), and manual separation on a stereoscopic microscope. Once the zircon concentrate is obtained, these are mounted on a FEP teflon mount, then polished and etched on an eutectic mix of 10 g. of KOH + 7.2 g. of NaOH, heated to 210 Centigrade degrees. Afterwards the mounts are prepared for irradiation, sterilizing and putting on top of them an external detector (a thin sheet of muscovite poor in uranium content). The package is then wrapped in plastic and sent to the reactor together with standard zircons of known age (Fish Canyon Tuff: Naeser et.al., 1981), mounted in the same way, plus standard glasses of known uranium content. The package was irradiated in a site known as SIRCA (Rotatory Capsules Irradiation System). Then the package is left to decay for several days, and then the external detectors are etched in a 48% concentrated hydrofluoric acid for 5 minutes. Once the samples are processed through the mentioned steps, spontaneous tracks appear in the zircons and induced tracks appear in the external detectors. On counting the tracks one obtains ρ s (spontaneous track density) and ρ 1 (induced track density). These two parameters together with another one called '#zeta #' (obtained from the standard zircons and glasses), are used to obtain the age of the sample. Zircons from Cerro de Mercado, Durango were dated and the age obtained was 30 ±5 Ma. This date is in agreement with similar results obtained by Fleisher and Naeser (1975) for zircons of the same locality and dated by the

  8. Development of uranium standard glass for fission tracks technology calibration

    International Nuclear Information System (INIS)

    Zhao Yunlong; Wu Zhaohui; Huang Qiuhong; Wang Bing; Zhai Pengji

    1997-07-01

    The uranium standard glass is developed to meet the need of application of fission tracks technology. It's main composition are SiO 2 , Na 2 O, CaO, Al 2 O 3 , etc. Tests indicate that uranium in the glass is well-distributed; the content (mass fraction) of element B is smaller than 3 μg/g, Cd smaller than 2.1 μg/g, and Th smaller than 0.3 μg/g. The acid-resisting property reaches the level of the first class optical glass; and the moist-resisting property reaches the level of the second class optical glass. The contents of uranium in UB1 and UB2 uranium glass determined by several laboratories are (1.89 +- 0.05) μg/g and (11.2 +- 0.2) μg/g respectively; the stability test after a year indicates that its properties are stable. (11 tabs., 1 figs.)

  9. Thermo chronology by the fission track method of a passive marge (Ponta Grossa dome in south-eastern Brazil) and within a collision chain (external zone of the alpine arch in France)

    International Nuclear Information System (INIS)

    Medeiros Vignol Lelarge, M.L.

    1993-01-01

    The dating method by counting fission tracks on apatite (this rock is a geo-thermometer sensitive to weak temperature changes below 150 Celsius degrees) is an efficient tool for the thermal history of rocks. We have used this method in 2 different geological contexts: the Ponta Grossa dome in south-eastern Brazil and the alpine mountain in France. This dating method is based on the fact that some rocks like mica keep fossil remains of the passage of the fission products emitted during the simultaneous fission of uranium 238 present in the rock. This method requires the irradiation in a slow neutron flux of the sample because the initial quantity of uranium is unknown. The age t of the sample is given by the formula: t=(1/l 1 )*ln[1+(r s /r i )*(l 2 /l 1 )*F*σ*I] where: l 1 is the alpha decay constant of U 238 ; l 2 is the simultaneous fission decay constant of U 238 , r s is the number of fission tracks in the sample before the irradiation; r i is the number of fission tracks induced by the irradiation; F is the thermal neutron flux; σ is the thermal fission cross-section of U 235 ; and I is the isotopic rate U 235 /U 238 . This document is divided into 4 chapters. The first chapter presents the general principle of the method, the mechanisms capable of producing fission tracks and the techniques used to make these tracks visible with an optical microscope. The second chapter deals with the conditions of the irradiation and the calibration of the method. The 2 last chapters are dedicated to the applications to the 2 geological contexts. (A.C.)

  10. Quantitative analysis from limited sampling: influence of the chemical composition of apatites on their resistance to irradiation damage

    International Nuclear Information System (INIS)

    Ribet, I.; Petit, J.C.; CEA Cadarache, 13 - Saint-Paul-lez-Durance

    1998-01-01

    Apatites are investigated as possible high performance radioactive waste matrices for specific actinides. In this paper, we have quantified the influence of the chemical composition of apatites on their fission-track annealing behaviour. We aimed to evaluate the capability of apatites to self-anneal high densities of radiation damages produced during disposal. The thermal annealing kinetics, at 280 deg. C, of induced fission tracks has been determined for six different apatite compositions. We show that the chemical composition of apatites is a critical parameter with respect to their annealing behaviour. A mathematical treatment of the data, based upon the methodology of optimum design of experiments, allowed the quantification of the role of substitution for two major elements, of the apatite structure (Ca, P), for chlorine and for the two groups of minor elements, actinides (U+Th) and lanthanides (La+Ce+Y), which are relevant in the nuclear waste disposal context. A high actinide content enhances the annealing of fission-tracks in apatites, which is a very favourable feature of these minerals as radioactive waste matrices. This work also points to a new strategy for the best use of information provided by geological samples. In particular, the mathematical methodology proposed here allows, first, to evaluate the 'quality' of the information obtained and, second, to improve it by a proper choice of additional samples to investigate. (authors)

  11. Fission distribution measurements of Atucha's fuel pellets with solid state track detectors

    International Nuclear Information System (INIS)

    Ricabarra, M.D. Bovisio de; Waisman, Dina.

    1979-08-01

    Distribution of fissions in a UO 2 rod has been measured by means of solid state detectors. Mica muscovite and Makrofol-N detectors were used in the experiment. The merits of mica muscovite relative to the Makrofol-N for the detection of fission fragments have been verified. However both fission track detectors closely agree (0,5%) in the final fission distribution of the UO 2 rod. Sensitivity of the detectors shows to be linear in the range between 50.000and 360.000 fission tracks per square centimeter. Due to the high spatial resolution this method is better than any other technique. Determination were made in UO 2 pellets similar to the fuel element of the Atucha reactor. The average fission rate in the rod has been measured within 0,8% error, and provides an accurate determination for the distribution of fissions in the rod wich is needed for the determination of energy liberated per fission in the natural uranium rod.(author) [es

  12. Etching behavior of fission fragment tracks in synthetic quartz and its application to neutron detection

    International Nuclear Information System (INIS)

    Sawamura, Teruko; Baba, Satoshi; Narita, Masakuni; Yamazaki, Hatsuo

    1994-01-01

    The etching behavior of fission fragment tracks in synthetic quartz plates concerning to +x, y and z planes was studied using NaOH solution as an etchant. Systematic experiments gave an optimum etching condition of 65% NaOH at 150degC suitable for track detection. Under this etching condition, following several properties were studied; the bulk etching rate, the etched track opening shape and its growth rate, the critical angle of track etching, and the irradiation effect of low LET radiation. All of three different cuts were demonstrated to be useful for plates as fission track detectors. An application to neutron detection was studied for the +x-plane of an x-cut plate. The detection sensitivity of the plane in close contact with a Th-radiator was 2.7x10 -6 tracks/fluence for 14 MeV neutrons. (author)

  13. Electron microscopic investigations of tracks of Cf252 fission fragments in quartz glass

    International Nuclear Information System (INIS)

    Werba, T.; Granzer, F.

    1977-01-01

    Using a single stage carbon replication technique, track pits of Cf 252 -fission products in quartz glass could be revealed by transmission electron microscopy with a high degree of resolution. From the shape of the track pits the angles of incidence of the nuclear particles were determined down to extremely small angles. In addition track pits on the fracture surface of irradiated quartz glass samples have been investigated by scanning electron microscopy. (author)

  14. Fission-track age (400,000 yr) of the Rockland tephra, based on inclusion of zirco grains lacking fossil fission tracks

    Science.gov (United States)

    Meyer, C.E.; Sarna-Wojcicki, A. M.; Hillhouse, J.W.; Woodward, M.J.; Slate, J.L.; Sorg, D.H.

    1991-01-01

    A zircon fission-track age of about 400,000 yr B.P. has been determined for the Rockland tephra, a widespread pyroclastic layer in northern California and western Nevada. New ages of zircon separates from both proximal and distal exposures of this layer range from 370,000 to 460,000 yr; ages of the best material provide a narrower range, from 370,000 yr for unwelded ash-flow tuff to 420,000 yr for distal air-fall ash that appears to be uncontaminated by clastic detritus or xenocrysts. Detrital or xenocrystic grains in the ash-flow tuff may have been annealed during emplacement and cooling of the tuff. Detrital and xenocrystic zircons are identified on the basis of their physical characteristics and distinctly older ages. Independent stratigraphic and magnetostratigraphic data constrain the age of the Rockland tephra between 300,000 and 600,000 yr, a range that is compatible with the fission-track age. Zircon grains containing no spontaneous (fossil) tracks are regarded as part of the normal population of comagmatic grains because maximum ages calculated for these grains form a population that mimics the distribution of ages of individual zircon grains that contain fossil tracks; modal ages of both groups fall between 250,000 and 500,000 yr. Induced fission tracks from grains that lack fossil tracks are included in the age calculations, resulting in significantly younger and more coherent dates than would result if these tracks had been omitted, especially those of the finer-grained distal samples. ?? 1991.

  15. Determination of the uranium concentration in soil solutions by the fission track registration technique

    International Nuclear Information System (INIS)

    Fernandes, G.P.

    1980-02-01

    The fission tracks registration technique was used to determine the uranium concentration in soil solutions. The Makrofol KG, a synthetic plastic manufactured by Bayer, was used as a detector and the wet method was applied. From the calibration curves obtained, it was possible to determine uranium concentrations in soil solutions, from 90 to 320 μg U/l, with an error between 9.4% and 4.0%, respectively. The method was applied to a few soil samples from Pocos de Caldas, Minas Gerais in Brazil. The uranium concentrations in the sample and residues were also determined by other methods to compare the results obtained; only one sample showed deviation from the results obtained by the fission tracks method. And this discrepancy was explained in a reasonable way. It was shown that the fission tracks technique can be used with sucess for application in soil solutions. (Author) [pt

  16. Determination in soils of soluble uranium fraction in acid medium by fission tracks registration techniques

    International Nuclear Information System (INIS)

    Fernandes, G.P.

    1980-01-01

    The fission tracks registration technique was used to determine the concentration of uranium in soil solutions. The Makrofol KG, a synthetic plastic manufactured by Bayer, was used as a detector and the wet method was applied. The method was applied to a few samples of soils from Pocos de Caldas, Minas Gerais in Brazil. The concentrations of uranium in the samples and residues were also determined by other methods to compare the results obtained; only one sample showed deviation among the results obtained by the fission tracks method. (author)

  17. Obsidian dating by fission track method; Datacao de obsidianas com o metodo dos tracos de fissao

    Energy Technology Data Exchange (ETDEWEB)

    Araya, A.M.O.

    1990-12-01

    The fission track method was employed to obtain the age of twelve obsidian sample from Ecuador. By using the plateau-age correction method, we obtained the true age of each sample and were able to identify four groups of ages in the studied area. Thereafter we studied the fading of fission tracks in two obsidian samples with different origins: Yanaurcu, Ecuador and Monte Arci, Italy. We constructed Arrhenius plots and calculated activation energies for both samples. The results from thermal annealing experiments were compared with theoretical curves obtained by integrating an equation proposed by Shukolyukov et al (1965). (author). 43 refs, 20 figs, 10 tabs.

  18. The measurement of the uranium content of crystals, glasses and meteorites with the fission track method

    International Nuclear Information System (INIS)

    Vartanian, R.

    1977-04-01

    In the present investigation, work has been carried out regarding the measurement of the uranium content of minerals, crystals and meteoritic samples from different parts of Iran. In this paper the method of inducing tracks from the 235 U indigenous to the Solid State Nuclear Track Detectors (SSNTDS) is described and new results have been attained. These are summarized as follows: Apatite between (4.16+-0.27) and (10.54+-0.84) ppm, Wulfnite=(4.90+-0.37) ppm, Quartz=(0.15+-0.02) ppm and Meteorite=(0.026+-0.003) ppm. (author)

  19. Geochronologic (K-Ar/Fission Track) east-west profile of the Rio Grande do Sul shield

    International Nuclear Information System (INIS)

    Poupeau, G.; Baitelli, R.; Berbert, M.; Kawashita, K.

    1985-01-01

    An E-W sampling was executed from Pelotas to Dom Pedrito, Rio Grande do Sul State, for K-Ar and fission-track (FT) dating. Within the Dom Feliciano Orogenic Belt, from Pelotas to Pinheiro Machado, K-Ar in biotites increase from 530 m.y. to 655 m.y., with a discontinuity at the level of the 10 km wide Cangacu cataclastic Zone. In two samples from the Rio de La Plata Craton, at the Western end of our profile, hornblendes present K-Ar ages of 1.555 m.y and 1.594 m.y. FT ages in apatites record the cooling of these minerals below 120+- 20 0 C. From Pelotas to Pinheiro Machado, four samples present concordant ages at 270+ -10 m.y., while the western sample records a later event at 216 m.y. From the structure of plateau-ages it is suggested that the events dated are two positive tectonic pulses. Examination of the sedimentary of the Parana Basin confirms this interpretation. We therefore dated isotopically, for the first time in Rio Grande do Sul basement, the ages of the two tectonic pulses which affected the sedimentation in the Parana Basin. (Author) [pt

  20. Geological evolution of the southwestern part of the Veporic Unit (Western Carpathians: based on fission track and morphotectonic data

    Directory of Open Access Journals (Sweden)

    Vojtko Rastislav

    2017-08-01

    Full Text Available Zircon and apatite fission track (FT and morphotectonic analyses were applied in order to infer quantitative constraints on the Alpine morphotectonic evolution of the western part of the Southern Veporic Unit which is related to: (1 Eo-Alpine Cretaceous nappe stacking and metamorphism of the crystalline basement in the greenschist facies. (2 Exhumation phase due to underthrusting of the northerly located Tatric-Fatric basement (~ 90–80 Ma, followed by a passive en-block exhumation with cooling through ~ 320–200 °C during the Palaeocene (ZFT ages of ~ 61–55 Ma. (3 Slow Eocene cooling through ~ 245–90 °C, which most likely reflected erosion of the overlying cover nappes and the Gosau Group sediments. Cooling reached up to 60 °C till the Oligocene (AFT ages of ~ 37–22 Ma in association with erosion of cover nappes. The efficient Eocene erosion led to the formation of the first Cenozoic planation surface with supergene kaolinization in many places. (4 The early Miocene erosion coincided with surface lowering and resulted in the second planation surface favourable for kaolinization. (5 In the middle Miocene, the study area was covered by the Poľana, Javorie, and Vepor stratovolcanoes. (6 The late Miocene stage was related to the erosion and formation of the third Cenozoic planation surface and the final shaping of the mountains was linked to a new accelerated uplift from the Pliocene.

  1. Geochronologic (K-Ar/Fission track) east-west profile of the Rio Grande do Sul shield

    International Nuclear Information System (INIS)

    Poupeau, G.; Baitelli, R.; Berbert, M.

    1985-01-01

    An E-W sampling was executed from Pelotas to Dom Pedrito, Rio Grande do Sul state, for K-Ar and Fission-track (FT) dating. Within the Dom Feliciano Orogenic Belt, from pelotas to Pinheiro Machado, K-Ar in biotites increase from 530m.y. to 655 m.y., with a discontinuity at the level of the approx.10Km wide Cangacu cataclastic Zone. In two samples from the Rio de La Plata Craton, at the western end of our profile, hornblendes present K-Ar ages of 1.555m.y. and 1.594m.y. FT ages in apatites record cooling of these minerals below 120 + - 20 0 C. From Pelotas to Pinheiro Machado, four sample present concordant ages at 270 + - 10m.y., whiel western most sample records a later event at 216 m.y. From the structure of plateau-ages it is suggested that the events dated are two positive tectonic pulses. Examination of the sedimentary of the Parana Basin confirms this interpretation. We therefore dated isotopically, for the firts time in Rio Grande do Sul basement, the ages of the two tectonic pulses wich affected the sedimentation in the Parana Basin. (Author) [pt

  2. Fission track and petrostructural analysis of carbonatic massif of Tamazert ( high central Atlas, Morocco) and neogene reactivation of the north-atlasic fault

    International Nuclear Information System (INIS)

    Ziad, N.; Khazrouni, S.; Tayebi, M.; Bouabdli, A.; Poupeau, G.

    2001-01-01

    The uranium fission-track dating method is used in geochronological survey of basic apatites extracted from the Tamazert complex. The result of this survey coupled with those of petrostructural analysis of this massif enabled as to distinguish three age groups: 32.4 Myr, 23.3 Myr and 12.6 Myr. The first age corresponds to the setting up of the massif, whereas the two other ages indicate later emissions. The setting up of the sill whose age is 12.6 Myr induced a partial rejuvenation of the emission age og the massif. This late volcanic emission is probably related to the north-atlasic fault activity. 4 figs., 1 tab., 30 refs. (au)

  3. ATOM: a semiautomatic measuring system for the analysis of fission track characteristics in anisotropic minerals

    International Nuclear Information System (INIS)

    Rebetez, M.; Zoppis, B.; Rebrab, A.; Grillon, P.; Gentina, E.; Chambaudet, A.

    1991-01-01

    We have developed a semiautomatic measuring system for the analysis of fission tracks in minerals. This system consists of an optical microscope equipped with a drawing tube which is connected to an IBM compatible computer equipped with a digitizer. ATOM is the software, developed using TURBO-PASCAL Version 4.0. It is presently used for performing data input on the densities, lengths and orientations of tracks. It also coordinates the activities of storing and processing the data of measured tracks and it gives the results of the statistical analysis. In this way, the mineral age determination can be made either by the Population Method (PM) or by the External Detector Method (EDM). The curves for fission track length distributions and orientations are drawn and may be printed out. This system's hardware and software are described in this paper. (author)

  4. Thorium content of a mineral ore from Morro do Ferro by fission track technique

    International Nuclear Information System (INIS)

    Oliveira, C.A.N. de.

    1980-10-01

    The feasibility to determine thorium concentrations by fission track technique in samples of mineral ore has been demonstrated. The literature registers only the application of the fission track technique to mineral ore in the case where the fissionable element is uranium. The technique was applied to determine the thorium concentration of an ore sample from Morro do Ferro, taking advantage of the high thorium to uranium ratio in that mineral. The sample analysed presented a thorium concentration of 2467 +- 400 mg Th/Kg ore. The so called wet method was adopted by using the Bayer made Makrofol KG 10μm thick, as the detector foil, immersed in the thorium solution. The technique is also useful to determine thorium concentrations in environmental samples because of the following aspects: high sensitivity; fast chemical separation of interfering elements; low cost; and operational simplicity. (Author) [pt

  5. A fission track technique used for hydrogeochemical prospecting in Northern India

    International Nuclear Information System (INIS)

    Singh, N.P.; Singh, S.; Virk, H.S.

    1988-01-01

    A fission track technique is employed to determine the uranium content of water samples collected from different locations of the middle and outer Himalayas. The regional threshold for the uranium content is determined for water samples of different areas. The identification of anomalies in an area of uranium mineralization confirmed that the hydrogeochemical technique could successfully be used for uranium exploration. (author)

  6. Fission-track evidence for apparent out-of-sequence Cenozoic deformation along the Philip Smith Mountain front, northeastern Brooks Range, Alaska

    Science.gov (United States)

    O'Sullivan, Paul B.; Wallace, Wesley K.; Murphy, John M.

    1998-12-01

    The northeastern Brooks Range (NEBR), bounded to the northwest by the Philip Smith Mountain front (PSMF), advanced northward from the east-trending main axis of the Brooks Range in Cenozoic time. The evolution of the PSMF is difficult to assess by conventional means because of a limited Cenozoic depositional record and poor exposures between the mountain front and the deformation front. 49 surface and 3 subsurface samples were collected along the northern flank of the PSMF to evaluate its thermal and tectonic history using apatite fission-track (AFT) data. Time-temperature modelling of the AFT data indicate that rocks exposed along the PSMF experienced maximum paleotemperatures in Late Cretaceous to Paleocene time and subsequently cooled during three episodes of km-scale denudation, at ˜60, ˜46, and ˜35 Ma. Apparent out-of-sequence deformation is indicated because successively younger ages are recorded to the southeast, approaching the range front from the foreland. This may reflect a hindward-propagating thrust sequence or apparent out-of-sequence deformation above a forward-propagating basal detachment due either to successive drops in the basal detachment or to deformation within the wedge. These results highlight the usefulness of fission-track data in revealing the age and distribution of tectonically driven unroofing and associated structural boundaries, particularly where they are otherwise difficult to recognize.

  7. Controls on Cenozoic exhumation of the Tethyan Himalaya from fission-track thermochronology and detrital zircon U-Pb geochronology in the Gyirong basin area, southern Tibet

    Science.gov (United States)

    Shen, Tianyi; Wang, Guocan; Leloup, Philippe Hervé; van der Beek, Peter; Bernet, Matthias; Cao, Kai; Wang, An; Liu, Chao; Zhang, Kexin

    2016-07-01

    The Gyirong basin, southern Tibet, contains the record of Miocene-Pliocene exhumation, drainage development, and sedimentation along the northern flank of the Himalaya. The tectonic controls on basin formation and their potential link to the South Tibetan Detachment System (STDS) are not well understood. We use detrital zircon (ZFT) and apatite (AFT) fission-track analysis, together with detrital zircon U-Pb dating to decipher the provenance of Gyirong basin sediments and the exhumation history of the source areas. Results are presented for nine detrital samples of Gyirong basin sediments (AFT, ZFT, and U-Pb), two modern river-sediment samples (ZFT and AFT), and six bedrock samples (ZFT) from transect across the Gyirong fault bounding the basin to the east. The combination of detrital zircon U-Pb and fission-track data demonstrates that the Gyirong basin sediments were sourced locally from the Tethyan Sedimentary Sequence. This provenance pattern indicates that deposition was controlled by the Gyirong fault, active since 10 Ma, whose vertical throw was probably slab during the middle Miocene, inducing dynamic uplift of the Indian plate overriding its own slab.

  8. Thermal and tectonic history of the Barrandian Lower Paleozoic, Czech Republic: is there a fission-track evidence for Carboniferous-Permian overburden and pre-Westphalian alpinotype thrusting? (Critical comments on the paper by Ulrich Mann and Günter A. Wagner)

    Czech Academy of Sciences Publication Activity Database

    Filip, Jiří; Suchý, V.

    2004-01-01

    Roč. 79, č. 2 (2004), s. 107-112 ISSN 1214-1119 R&D Projects: GA AV ČR(CZ) IAA3012703 Grant - others:DFG(DE) Ma 1861/1-1 Keywords : apatite fission-track analysis * Barrandian * Variscan Orogeny Subject RIV: DB - Geology ; Mineralogy http://www.geology.cz/bulletin/contents/2004/vol79no2/bullgeosci200402107.pdf

  9. Fission track astrology of three Apollo 14 gas-rich breccias

    Science.gov (United States)

    Graf, H.; Shirck, J.; Sun, S.; Walker, R.

    1973-01-01

    The three Apollo 14 breccias 14301, 14313, and 14318 all show fission xenon due to the decay of Pu-244. To investigate possible in situ production of the fission gas, an analysis was made of the U-distribution in these three breccias. The major amount of the U lies in glass clasts and in matrix material and no more than 25% occurs in distinct high-U minerals. The U-distribution of each breccia is discussed in detail. Whitlockite grains in breccias 14301 and 14318 found with the U-mapping were etched and analyzed for fission tracks. The excess track densities are much smaller than indicated by the Xe-excess. Because of a preirradiation history documented by very high track densities in feldspar grains, however, it is impossible to attribute the excess tracks to the decay of Pu-244. A modified track method has been developed for measuring average U-concentrations in samples containing a heterogeneous distribution of U in the form of small high-U minerals. The method is briefly discussed, and results for the rocks 14301, 14313, 14318, 68815, 15595, and the soil 64421 are given.

  10. Experimental examination of ternary fission in nuclear track emulsion

    Czech Academy of Sciences Publication Activity Database

    Mamatkulov, K. Z.; Ambrožová, Iva; Artemenkov, D. A.; Bradnova, V.; Firu, E.; Haiduc, M.; Kákona, Martin; Kattabekov, R. R.; Marey, A.; Neagu, A.; Ploc, Ondřej; Rusakova, V. V.; Stanoeva, R.; Turek, Karel; Zaitsev, A. A.; Zarubin, P. I.; Zarubina, I. G.

    2017-01-01

    Roč. 48, č. 6 (2017), s. 910-913 ISSN 1063-7796 Institutional support: RVO:61389005 Keywords : angular correlation * nuclear track emulsion Subject RIV: BF - Elementary Particles and High Energy Physics OBOR OECD: Particles and field physics Impact factor: 0.681, year: 2016

  11. Fission-track evidence of tectonic evolution in the northwestern ...

    Indian Academy of Sciences (India)

    track evidence of tectonic evolution in the ... The later (1.2–32.0 Ma) tectonothermal event resulted from further collision of the Indian and Eurasian plates along the Yarlung Tsangpo suture zone. Strata in the Qaidam Basin were further ...

  12. Observations of fission-tracks in zircons by atomic force microscope

    International Nuclear Information System (INIS)

    Ohishi, Shinnosuke; Hasebe, Noriko

    2012-01-01

    The fission-track (FT) method is a dating technique based on the observation of damage (tracks) by spontaneous fission of 238 U left in a mineral. The date is calculated from the track density and the uranium concentration in the mineral. This is possible because the number of tracks is a function of uranium concentration and time since the start of track accumulation. Usually, the number of tracks is counted under an optical microscope after etching (chemical expansion of a track). However, as FT density per unit area rises, it becomes difficult to count the number of tracks. This is due to the fact that FTs overlap one another and are unable to be readily distinguished. This research examines the potential of atomic force microscope (AFM) for FT dating using zircons, which are likely to show higher FT density than other minerals due to their high U concentrations. To obtain an AFM image for a sample prepared for FT dating, removing the static electricity of the sample is essential to avoid an unexpected movement of the cantilever. A grain should be wider than about 30 μm to bring the cantilever on the mineral surface. Polishing with a fine grained compound is very important. There is not much difference in sharpness between images by AC mode (scanning with vibrating cantilever at a constant cycle) and Contact mode (scanning with the cantilever always in close contact with the surface). To confirm how tracks can be identified with the AFM, an AFM image was compared with an image obtained with the optical microscope. When change in the number of tracks and their shapes were observed through stepwise etching, the track expanded as the etching time increased. In addition, the etching rate was slower for large tracks than those for small tracks. This implied that the AFM can be used to observe etching of zircons with different degrees of nuclear fission damage. A track that could not be seen with the optical microscope due to insufficient etching could be observed by

  13. Irradiation positions for fission-track dating in the University of Pavia TRIGA Mark II nuclear reactor

    International Nuclear Information System (INIS)

    Oddone, Massimo; Meloni, Sandro; Balestrieri, Maria Laura; Bigazzi, Giulio

    2002-01-01

    An irradiation position arranged is described in the present paper for fission-track dating in the Triga Mark II reactor of the University of Pavia. Fluence values determined using the NIST glass standard SRM 962a for fission-track dating and the traditional metal foils are compared. Relatively good neutron thermalization (φ th /φ f = 0.956) and lack of significant fluence spatial gradients are good factors for fission-track dating. Finally, international age standards (or putative age standards) irradiated in this new position yielded results consistent with independent reference ages. (author)

  14. Liquid nitrogen enhancement of partially annealed fission tracks in glass; and reply

    International Nuclear Information System (INIS)

    Wagner, G.A.; Carpenter, B.S.; Pilione, L.J.; Gold, D.P.

    1977-01-01

    Pilione and Gold (Nature 262: 773 (1976)) stated that it was possible to reveal partially annealed fission tracks in glass by immersion in liquid N 2 , and that it was possible to increase the total number of etchable tracks by increasing the immersion time. The present authors attempted to duplicate the work of the former authors using the same glass. They found no significant change in the number of etchable tracks after immersion in liquid N 2 , and they concluded that the latter has no effect on annealed tracks in glass. Any observed enhancement of partially annealed tracks is probably a surface effect and has no effect on the interior matrix of the glass. A reply by Pilione and Gold is appended. (U.K.)

  15. Use of fission track for deciphering the dissolution mechanism of silicates glasses

    International Nuclear Information System (INIS)

    Petit, J.C.; Brousse, C.

    1985-09-01

    Polished sections of silicate glasses containing latent or pre-etched fission tracks have been subjected to corrosion in deionized water or NaCl brines at 20, 50 and 100 0 C. The evolution of glass surface helps deciphering among reported dissolution models. We show that ion-exchange is dominant in simple glasses while in complex ones, dissolution involves several steps including an in-situ transformation of the pristine material and a reprecipitation of dissolved species

  16. Thorium and uranium determinations in rock solutions by the induced fission track method

    International Nuclear Information System (INIS)

    Bajo, C.

    1979-01-01

    Thorium and uranium have been determined by counting induced fission tracks. While for uranium determinations no chemical separation was required, the thorium was first separated using the strongly basic anion-exchange resin, Dowex 1 x 8 in a mixed medium consisting of 5M HNO 3 and methanol. This was done by batch rather than column method. The feasibility of the method was established by analysing standard rocks. A precision of +- 5 to 10% and an accuracy of +- 10% were obtained. (author)

  17. Response studies of fission track detectors within moderators in CAVE A at GSI

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, S., E-mail: Sabine.Mayer@psi.c [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Boschung, M.; Fiechtner, A.; Hohmann, E. [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Fehrenbacher, G.; Radon, T.; Pleskac, R.; Wengenroth, M. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Planckstrasse 1, 64291 Darmstadt (Germany)

    2010-12-15

    At the Paul Scherrer Institut (PSI) fission track detectors are routinely used in moderators for determining the ambient dose equivalent in stray radiation fields due to neutrons. At the high-energy field CERF (CERN EU high-energy reference field) at CERN, the response of fission track detectors within two different moderators, where one moderator has an inlay of Pb to increase the response of the detector to high-energy neutrons, was surprisingly similar. To confirm this unexpected behaviour, a measurement campaign in another high-energy field, i.e. CAVE A at the Helmholtzzentrum fuer Schwerionenforschung (GSI) was carried out. CAVE A at GSI is one of few facilities where a stray radiation field with neutrons above 20 MeV can be generated under controlled conditions. Reference doses were obtained by simulating the stray radiation field in the measurement positions. These simulations were carried out independently by GSI and PSI using two different Monte Carlo codes, i.e. Fluka and MCNPX, respectively. In this paper the measurements at GSI are described in detail. The results are then compared to previous measurement campaigns in the radiation field of CERF as well as {sup 241}Am-Be and {sup 252}Cf radionuclide sources, which all feature different neutron spectra. None of these campaigns confirm the improvement in sensitivity of the Pb enhanced moderator compared to the PSI standard moderator in combination with fission track detectors.

  18. Raman spectroscopy and scanning electron microscopy characterizations of fission track method datable zircon grains.

    Science.gov (United States)

    Resende, Rosana Silveira; Sáenz, Carlos Alberto Tello; Curvo, Eduardo Augusto Campos; Constantino, Carlos José Leopoldo; Aroca, Ricardo F; Nakasuga, Wagner Massayuki

    2014-01-01

    Spectroscopic and morphological studies, designed to improve our understanding of the physicochemical phenomena that occur during zircon crystallization, are presented. The zircon fission track method (ZFTM) is used routinely in various laboratories around the world; however, there are some methodological difficulties needing attention. Depending on the surface fission track density observed under an optical microscope, the zircon grain surfaces are classified as homogeneous, heterogeneous, hybrid, or anomalous. In this study, zircon grain surfaces are characterized using complementary techniques such as optical microscopy (OM), micro-Raman spectroscopy, and scanning electron microscopy (SEM), both before and after chemical etching. Our results suggest that anomalous grains have subfamilies and that etching anisotropy related to heterogeneous grains is due to different crystallographic faces within the same polished surface that cannot be observed under an optical microscope. The improved methodology was used to determine the zircon fission track ages of samples collected from the Bauru Group located in the north of Paraná Basin, Brazil. A total of 514 zircon grains were analyzed, consisting of 10% homogeneous, about 10% heterogeneous, about 20% hybrid, and 60% anomalous grains. These results show that the age distributions obtained for homogeneous, heterogeneous, and hybrid grains are both statistically and geologically compatible.

  19. Development of the fission fragment track registration technique for the determination of the uranium contamination

    International Nuclear Information System (INIS)

    Tanaka, E.M.

    1979-01-01

    The Fission Fragment Track Registration Technique is developed to measure the uranium concentration about microgram of uranium per litre of liquid samples. The drying method of drops on the detector (Makrofol KG) and a special sampling procedure to avoid the cumbersome high density of tracks formation at the edge of the deposition surface as a 'ring' is adopted. The samples are irradiated by neutrons produced by the IEA-R1 Reactor (thermal neutron flux about 10 12 neutrons/cm 2 .s) inducing the uranium fission. The tracks registered by the fission fragments in the detector are chemically enlarged and counted by an automatic couting system. By this method the uranium concentrations ranging from 0,9 to 7,6 microgram of uranium per litre, can be determined with precisions between 2,7% the greater and 23% to the lower concentration. The uranium concentration measurements in human hair and urine are made showing that this method is very useful to control and detect eventual uranium contamination [pt

  20. Natural uranium impurities in fission track detectors and associated geocronological parameters

    International Nuclear Information System (INIS)

    Ricabarra, G.H.; Bovisio de Ricabarra, M.D.; Waisman, Dina; Faradjie de Turjanski, Rosa

    1981-01-01

    A technique, based in counting neutron induced fission tracks, has been developed for the measurement of uranium impurities in mica. Uranium concentrations of 10 -10 and 10 -9 (U atom/mica atom) have been measured. As a part of the development of this technique, the mica geological age was also measured, by fossil and induced track detection. The agreement obtained by this method, T = (472+-52) x 10 6 years with that of (450+-15) x 10 6 years obtained by the Ar-K technique is satisfactory and is an indirect test of the fission track technique used. A careful analysis of the neutron field parameters and nuclear data used in the age determination was made. This analysis is useful for applications in geocronology. According to this analysis a value of lambdasub(f)=(7.1+-0.1) x 10 -17 years -1 is recommended for the spontaneous fission of U238. However, in order to compare the results, the quoted age, T=(472+-52) x 10 6 years, was obtained with the generally accepted value of lambdasub(f)=(6.85-0.20) x 10 -17 years -1 (Fleischer and Price 1964). (author) [es

  1. Late Cretaceous-Cenozoic exhumation of the southeastern margin of Coastal Mountains, SE China, revealed by fission-track thermochronology: Implications for the topographic evolution

    Directory of Open Access Journals (Sweden)

    Xiaoming Li

    2017-09-01

    Full Text Available Apatite and zircon fission-track (FT analyses were used to reveal the Late Cretaceous-Cenozoic exhumation of the Southeastern margin of Coastal Mountains (SCM, Southeast (SE China. Zircon FT ages ranging from 92 ± 5 to 98 ± 6 Ma, and apatite from 54 ± 4 to 68 ± 6 Ma with mean measured track lengths between 12.2 ± 1.6 and 12.9 ± 2.0 μm, were obtained for the granitoids sampled along an east to west transect across the SCM. The three-stage, involving the first rapid stage, following by slow stage, and finally accelerated cooling stage, and inferred exhumation since the Late Cretaceous have been identified in the study region based on the FT data and modeling results. Assuming a steady-state paleogeothermal gradient of 25 °C/km founded on geological setting, the exhumations of 4000 m, 2000 m and 1600 m, and the paleoelevation decreases of 727 m, 364 m and 291 m, were achieved in the SCM, during 94–60 Ma, 60–25 Ma and 25–0 Ma, respectively. This hence reveals that the paleoelevation in the SCM was decreased rapidly from ∼1400 m a.s.l. in the early Late Cretaceous to ∼650 m a.s.l. in the early Paleogene, subsequently slowly to ∼300 m a.s.l. in the Late Oligocene, and finally to ∼0 m a.s.l. in the present at an accelerated rate. Our results indicate that the SCM experienced an episodic exhumation, and successive decreases in paleoelevation, predominantly induced by complex geodynamic processes.

  2. Studies on the Th biodistribution in internal contamination by the fission track method using animals

    International Nuclear Information System (INIS)

    Ciubotariu, M.; Danis, A.; Dumitrescu, G.; Cucu, M.

    1998-01-01

    In our previous studies on the U internal contamination, qualitative and quantitative results were obtained by using the fission track methods. In order to obtain complete data on the fissionable element internal contamination using animals, we started a similar study using Th as contaminating element and Wistar London breed rats as laboratory animals. Different ways to obtain internal contaminations were investigated: ingestion, inhalation, absorption by skin and through wounds. In this stage, Wistar-London breed rats of the same sex, weight and age were internal contaminated by 1 ml Th solution ingestion for each rat corresponding to an Annual Limit Intake.The animals were kept in normal life conditions and under permanent medical surveillance up to their sacrifice. Also, their evacuations where sampled every 24 hours. They were sacrificed at different time intervals after their contamination: 2 days (RAT 1), 7 days (RAT 2) and 14 days (RAT 3). After sacrifice, their vital organs were sampled, weighed, calcined, reweighed and finally analysed by track detection using the fission track micromapping technique. This technique was used in the following conditions: - mica-muscovite as track detector pre-etched for fossil tracks 18 h in HF; - the neutron irradiations were performed in the nuclear reactor VVR-S Bucharest at the neutron fluences of 3x10 15 - 2x10 16 fast neutrons/cm 2 . In order to check whether there is any U contribution to the fission track densities obtained in track detectors, U existing in the rat body due to food and water, the neutron irradiations of the ensembles were performed with and without 1 mm Cd shielding; - the visualization of the Th induced fission tracks were obtained by chemical etching in HF, 3 h at room temperature; - the Th track micromappings obtained in track detectors were studied by optical microscopy using a stereomicroscope WILD M7S for ensemble study (X6-X31) and a binocular ZEISS JENA microscope for qualitative and

  3. On the frequency distributions per unit area of the projected and etchable lengths of surface-intersecting fission tracks: influences of track revelation, observation and measurement

    CERN Document Server

    Jonckheere, R

    1999-01-01

    In addition to the statistical bounds discussed, thermal history analysis based on the projected and etchable length distributions of surface intersecting fission tracks is limited by systematic factors related to track revelation, observation and measurement. The effects of track revelation, in particular, distort these distributions in the length intervals of interest. An observation threshold poses a problem if it is described by a critical angle theta sub c , but not if it is described by other criteria proposed in the literature. Measurement imprecisions, predictably, blur the thermal history information contained in these distributions. Measurements of semi-confined tracks, added as a result of surface etching, are a more promising alternative to confined track length measurements for accessing the thermal history record in the fission track length distribution. On the other hand, measurements of the projected lengths of surface intersecting tracks offer the theoretical possibility of determining the tr...

  4. International Union of Geological Sciences Subcommission on Geochronology recommendation for the standardization of fission track dating calibration and data reporting

    International Nuclear Information System (INIS)

    Hurford, A.J.

    1990-01-01

    Because of the difficulties of calibration in fission track (FT) dating over the last 20 yr, including uncertainty of the absolute λ f value, complexities of neutron dosimetry, complexities of neutron irradiation, correction factors necessary in some methodological procedures, and personal factors in track counting, the Working Group elected at the Cambridge ICOG meeting in 1986 recommended to FT workers meeting at the 6th International Fission Track Dating Workshop in Besancon on 9 September 1988, a uniform approach to system calibration, sample irradiation, calculation of FT age, and presentation of data. After discussion and modification, the recommendation was accepted. This modified recommendation is presented. (author)

  5. Solid state nuclear track detectors in the measurement of alpha to fission branching ratios of heavy actinides

    International Nuclear Information System (INIS)

    Pandey, A.K.; Sharma, R.C.; Padalkar, S.K.; Kalsi, P.C.; Iyer, R.H.

    1992-01-01

    A sequential etching procedure for revelation of alpha and fission tracks in CR-39 was developed and optimized. Using this technique alpha and fission tracks can be differentiated unambiguously because of significant differences in their sizes and etching times. This registration and revelation procedure for alpha and fission tracks may be used for the studies of half lives, alpha to fission branching ratios and identification of radionuclides based on their decay schemes. It has the added advantage that both alpha decay and fission events can be studied using one detector and hence uncertainties related to efficiency, registration geometry, registration times, amount of radionuclides etc can be eliminated or minimized. The effects of neutron, gamma and alpha radiations on the alpha and fission fragment tracks registration and revelation properties of CR-39 detectors [CR-39, CR-39 (DOP)] were also studied. The IR spectra were also studied to find out the nature of chemical changes produced by these radiations on CR-39. (author). 32 refs., 7 figs., 4 tabs

  6. Fission track dating of authigenic quartz in red weathering crusts of carbonate rocks in Guizhou province

    International Nuclear Information System (INIS)

    Liu Xiuming; Wang Shijie; Zhang Feng

    2004-01-01

    The Cenozoic evolution history of Guizhou Province, which is located on the southeastern flank of the Qinghai-Tibet Plateau, is unclear because of the lack of sedimentation records. The red weathering crusts widespread on the Yunnan-Guizhou Plateau may bear critical information about their evolution history. This work firstly determined the ages of four red weathering crusts in eastern, central and northern Guizhou. The material used in fission track dating is well-crystallized quartz occurring in many in-situ weathering crusts of carbonate rocks. The results showed that the fission track ages of quartz vary over a wide range from 1 Ma to 25 Ma in the four profiles, significantly younger than the ages of Triassic and Cambrian parent rocks. In combination with the regionally geological evolution history during the period from 25 Ma to 1 Ma, the ages of quartz can exclude the possibility that the origin of quartz has nothing to do with primary clastic minerals in parent rocks, authigenesis during diagenesis and hydrothermal precipitation or replacement by volcanic activities. It is deduced that the well-crystallized quartz was precipitated from Si-rich weathering fluids during weathering processes of carbonate rocks. The recorded ages of quartz from the four profiles are consistent with the episodes of planation surfaces on the Qinghai-Tibet Plateau, the stages of red soil in the tropics of South China, the tectonically stable periods in Guizhou, and the ages of weathering in other parts of the world during the Cenozoic era. That is to say, the ages of authigenic quartz dated by the fission track method are well feasible and credible. (authors)

  7. Effects of etching on zircon grains and its implications for the fission track method.

    Science.gov (United States)

    Tello Sáenz, Carlos Alberto; Curvo, Eduardo Augusto Campos; Dias, Airton Natanael Coelho; Soares, Cleber José; Constantino, Carlos José Leopoldo; Alencar, Igor; Guedes, Sandro; Palissari, Rosane; Hadler Neto, Julio Cesar

    2012-05-01

    Studies of zircon grains using optical microscopy, micro-Raman spectroscopy, and scanning electron microscopy (SEM) have been carried out to characterize the surface of natural zircon as a function of etching time. According to the surface characteristics observed using an optical microscope after etching, the zircon grains were classified as: (i) homogeneous; (ii) anomalous, and (iii) hybrid. Micro-Raman results showed that, as etching time increases, the crystal lattice is slightly altered for homogeneous grains, it is completely damaged for anomalous grains, and it is altered in some areas for hybrid grains. The SEM (energy dispersive X-ray spectroscopy, EDS) results indicated that, independent of the grain types, where the crystallinity remains after etching, the chemical composition of zircon is approximately 33% SiO(2):65% ZrO(2) (standard natural zircon), and for areas where the grain does not have a crystalline structure, there are variations of ZrO(2) and, mainly, SiO(2). In addition, it is possible to observe a uniform surface density of fission tracks in grain areas where the determined crystal lattice and chemical composition are those of zircon. Regarding hybrid grains, we discuss whether the areas slightly altered by the chemical etching can be analyzed by the fission track method (FTM) or not. Results of zircon fission track and U-Pb dating show that hybrid and homogeneous grains can be used for dating, and not only homogeneous grains. More than 50 sedimentary samples from the Bauru Basin (southeast Brazil) were analyzed and show that only a small amount of grains are homogeneous (10%), questioning the validity of the rest of the grains for thermo-chronological evolution studies using zircon FTM dating.

  8. Interrogating the Effects of Radiation Damage Annealing on Helium Diffusion Kinetics in Apatite

    Science.gov (United States)

    Willett, C. D.; Fox, M.; Shuster, D. L.

    2015-12-01

    Apatite (U-Th)/He thermochronology is commonly used to study landscape evolution and potential links between climate, erosion and tectonics. The technique relies on a quantitative understanding of (i) helium diffusion kinetics in apatite, (ii) an evolving 4He concentration, (iii) accumulating damage to the crystal lattice caused by radioactive decay[1], and (iv) the thermal annealing of such damage[2],[3], which are each functions of both time and temperature. Uncertainty in existing models of helium diffusion kinetics has resulted in conflicting conclusions, especially in settings involving burial heating through geologic time. The effects of alpha recoil damage annealing are currently assumed to follow the kinetics of fission track annealing (e.g., reference [3]), although this assumption is difficult to fully validate. Here, we present results of modeling exercises and a suite of experiments designed to interrogate the effects of damage annealing on He diffusivity in apatite that are independent of empirical calibrations of fission track annealing. We use the existing experimental results for Durango apatite[2] to develop and calibrate a new function that predicts the effects of annealing temperature and duration on measured diffusivity. We also present a suite of experiments conducted on apatite from Sierra Nevada, CA granite to establish whether apatites with different chemical compositions have the same behavior as Durango apatite. Crystals were heated under vacuum to temperatures between 250 and 500°C for 1, 10, or 100 hours. The samples were then irradiated with ~220 MeV protons to produce spallogenic 3He, the diffusant then used in step-heating diffusion experiments. We compare the results of these experiments and model calibrations to existing models. Citations: [1]Shuster, D., Flowers R., and Farley K., (2006), EPSL 249(3-4), 148-161; [2]Shuster, D. and Farley, K., (2009), GCA 73 (1), 6183-6196; [3]Flowers, R., Ketcham, R., Shuster, D. and Farley, K

  9. Post-emplacement kinematics and exhumation history of the Almora klippe of the Kumaun-Garhwal Himalaya, NW India: revealed by fission track thermochronology

    Science.gov (United States)

    Singh, Paramjeet; Patel, R. C.

    2017-09-01

    Tectonically transported crystalline thrust sheet over the Lesser Himalayan meta-sedimentary zone along the Main Central Thrust (MCT) is represented by Almora, Baijnath, Askot and Chiplakot crystalline klippen. The Almora-Dadeldhura klippe in the Kumaun-Garhwal and western Nepal Himalaya is the witness and largest representative of these crystalline klippen, south of MCT. Here, we investigate the post-emplacement kinematics and exhumation history of the Almora klippe. The newly derived zircon fission track (ZFT) ages combined with published apatite fission track (AFT), 40Ar-39Ar ages from the Almora-Dadeldhura klippe and Ramgarh thrust sheet to quantify the temporal variation in cooling ages and exhumation rates. Using 1-D numerical modelling approach, we calculate the transient exhumation rates with respect to different time intervals. New ZFT cooling ages along 50-km-long orogeny perpendicular transect across the Almora klippe range between 13.4 ± 0.6 and 21.4 ± 0.9 Ma. Published AFT ages and 40Ar-39Ar ages from the Almora-Dadeldhura klippe range 3.7 ± 0.8-13.2 ± 2.7 and 18.20-25.69 Ma, respectively. AFT ages reported from Ramgarh thrust sheet range 6.3 ± 0.8-7.2 ± 1.0 Ma in Kumaun region and 10.3 ± 0.5-14.4 ± 2.2 Ma in western Nepal. The linear age trend along with youngest ZFT age ( 14 Ma) close to the North Almora Thrust (NAT) in its hanging wall suggests rapid uplift close to the NAT due to its reactivation as back thrust. The transient exhumation rates of Almora klippe agree that the erosion rate was rapid (0.58 mma-1) close to the NAT in its hanging wall and relatively slow (0.31 mma-1) close to the SAT in its hanging wall during 15-11 Ma. We interpret that the fission track ages and transient exhumation rate pattern of crystalline klippen show a dynamic coupling between tectonic and erosion processes in the Kumaun-Garhwal Himalaya. However, the tectonic processes play the major role in controlling the exhumation pattern.

  10. Determination of the uranium concentration in water samples by the technique of fission track recording

    International Nuclear Information System (INIS)

    Geraldo, L.P.

    1979-01-01

    The technique of fission track register was developed for the determination of micrograms of uranium. The Makrofol KG, a synthetic plastic made by Bayer, was used as the detector and the wet method was utilized. The detector calibration curve allows the determination of the uranium concentration in a sample within an interval from 8.0 to 0.4μgU/L, the total error ranging from 3.3% to 29.0% respectively. The method was used in the determination of the uranium content in various water samples, obtained from various sources like rivers, sea etc. in the state of Sao Paulo, Brazil. Results were compared with those obtained by other authors using different methods. The average concentration found in sea waters (3.27 +- 9.12μgU/l) by this method is compatible with the international average accepted value of 3.3μgU/l, irrespective of site and depth. The determination of the uranium content by fission track counting has proved to be very convenient. (Author) [pt

  11. Thermo chronology by fission tracks of the conjugated rift margins of the Liguro-Provencal basin: Corsica and the Maures-Tanneron Massif

    International Nuclear Information System (INIS)

    Jakni, B.

    2000-01-01

    We have employed apatite fission-track (AFT) thermo-chronology on granitic and metamorphic samples taken from Corsican and Maures-Tanneron basement rocks as well as alpine 'schistes lustres' units in Corsica, in order to constrain the cooling histories and the tectonic evolution of the Liguro-Provencal basin margins. The AFT data indicate that: -) the Tanneron massif (AFT ages 145- 150 My) appears to record the earliest cooling history, reflecting thermal relaxation related to opening of the Tethys; -) the Maures basement (AFT ages 20-25 My) clearly records a thermo- tectonic evolution associated with Liguro-Provencal rifting; -) the island of Corsica, which was the main focus of this work and which shows a complex geomorphology and a poly-phased tectonic evolution. shows a remarkable zoning in the distribution of AFT ages, reflecting the signature of at least two post-Oligocene thermal events. Those events are related to the opening of Liguro-Provencal basin (20-25 My) in the west, and exhumation of the Hercynian basement related to Tyrrhenian extension (12- 16 My) in the east. In the east-Tenda shear zone, which forms the contact between the alpine units and Hercynian basement in northern Corsica, our results indicate that the Tenda Massif was being exhumed from about 21 Ma onwards. (author)

  12. Fission-track dating of pumice from the KBS Tuff, East Rudolf, Kenya

    Science.gov (United States)

    Hurford, A.J.; Gleadow, A.J.W.; Naeser, C.W.

    1976-01-01

    Fission-track dating of zircon separated from two pumice samples from the KBS Tuff in the Koobi Fora Formation, in Area 131, East Rudolf, Kenya, gives an age of 2.44??0.08 Myr for the eruption of the pumice. This result is compatible with the previously published K-Ar and 40Ar/ 39Ar age spectrum estimate of 2.61??0.26 Myr for the KBS Tuff in Area 105, but differs from the more recently published K-Ar date of 1.82??0.04 Myr for the KBS Tuff in Area 131. This study does not support the suggestion that pumice cobbles of different ages occur in the KBS Tuff. ?? 1976 Nature Publishing Group.

  13. Trace uranium determination in beverages and mineral water using fission track techniques

    International Nuclear Information System (INIS)

    Cheng, Y.L.; Lin, J.Y.; Hao, X.H.

    1993-01-01

    The uranium contents of beverages and mineral water have been estimated using the technique of fission track analysis with polycarbonate detector. The U contents in beverages have been found to vary from 0.26 ± 0.03 to 1.65 ± 0.07 ppb, the average value is 0.93 ± 0.05 ppb. The mean U content in mineral water is 9.20 ± 0.16 ppb, which is ∼ 10 times higher than the mean U content of beverages. The present study shows the high U content in mineral water, indicating need for further investigation of U content in mineral water for the studies of radiation health hazards. (Author)

  14. (1068 MeV) pi bar induced fission in gold observed with CR-39 plastic track detectors

    International Nuclear Information System (INIS)

    Javed, M.T.; Ahmad, S.M.; Shahzad, M.I.; Qureshi, I.E.; Sher, G.; Niazi, M.I.K.; Khan, H.A.

    1998-01-01

    In this paper results of the study of (1068 MeV) negative pion induced fission in a gold have been presented. To detect the reaction products emitted in the forward as well as backward hemisphere, a 4 pi configuration of exposure geometry was made by sandwiching the target material (gold) between two pieces of CR-39 plastic track detectors. This target-detector assembly was exposed at normal incidence to (1068 MeV) pi having a fluence of 8.55 x 10/sup 8/ pions/cm/sup 2/ at Low Energy Pion (LEP) channel of Clinton P. Anderson Meson Physics Facility (LAMPF), Brookhaven National Laboratory, USA. After exposure the gold layer was removed using aqua regia and then both the detectors were etched in 6N NaOH at (70 -+ 1) deg. C for 25 minutes to reveal the tracks. The number of fission fragment tracks in both the detectors were counted. The number of fission tracks in the detector placed downstream of the incident pion beam were found to be greater than those in the detector placed upstream. This difference has been attributed to the transfer of momentum in the forward direction due to the impact of pions. Reaction cross section has been calculated by taking into account the track statistics of both the detectors. (authors)

  15. Convection methodology for fission track annealing: direct and inverse numerical simulations in the multi-exponential case

    International Nuclear Information System (INIS)

    Miellou, J.C.; Igli, H.; Grivet, M.; Rebetez, M.; Chambaudet, A.

    1994-01-01

    In minerals, the uranium fission tracks are sensitive to temperature and time. The consequence is that the etchable lengths are reduced. To simulate the phenomenon, at the last International Conference on Nuclear Tracks in solids at Beijing in 1992, we proposed a convection model for fission track annealing based on a reaction situation associated with only one activation energy. Moreover a simple inverse method based on the resolution of an ordinary differential equation was described, making it possible to retrace the thermal history in this mono-exponential situation. The aim of this paper is to consider a more involved class of models including multi-exponentials associated with several activation energies. We shall describe in this framework the modelling of the direct phenomenon and the resolution of the inverse problem. Results of numerical simulations and comparison with the mono-exponential case will be presented. 5 refs. (author)

  16. The spark counting of etched fission-fragment tracks in polycarbonate for a personal neutron dosimetry system

    International Nuclear Information System (INIS)

    Harrison, K.G.; Hancock, I.B.; Holt, P.D.; Wylie, J.W.

    1977-10-01

    A new type of personal neutron dosimeter, in which neutron-induced fissions in a thin 237 Np foil are detected by a polycarbonate track-detector, is under development at Harwell for use in a nuclear-fuel reprocessing plant. As part of the development programme, an experimental dosimeter, etching facility and spark counter have been used to study the spark-counting method for counting fission-fragment tracks in polycarbonate. Emphasis has been placed on developing operating procedures for the counter consistent with good overall reproducibility. Existing methods for the optimizing and testing of spark counters is briefly reviewed and a practical operational testing procedure is devised. The optimized system is found to be relatively foolproof in operation and gives good results in unskilled use as well as under carefully-controlled laboratory conditions. (author)

  17. Distribution of uranium in dental porcelains by means of the fission track method

    International Nuclear Information System (INIS)

    Shimizu, Masami; Noguchi, Kunikazu; Moriwaki, Kazunari; Sairenji, Eiko

    1980-01-01

    Porcelain teeth, some of which contain uranium compounds for aesthetic purpose, have been widely used in dental clinics. Hazardous effects due to uranium radiation have been suggested by recent publications. In the previous study, the authors reported the uranium content of porcelain teeth and radiation dose by it. In this study, using the fission track method, the authors examined spatial distribution of uranium in dental porcelain teeth (4 brands) which were marketed in Japan. From each sample of porcelain tooth, a 1-mm-thick specimen was sliced, and uranium content was measured at every 0.19 mm from labial side to lingual side for making a uranium distribution chart. Higher uranium concentration was found in Trubyte Bioblend porcelain teeth (USA) and they showed almost uniform distribution of uranium, while those of the Japanese three brands indicated, in most case, comparatively lower concentration and found to be non-uniform distributions. Range of uranium concentration in these brands were N.D. -- 5.2 ppm (Shofu-Ace), N.D. -- 342 ppm (Shofu-Real), N.D. -- 47 ppm (G.C. Livdent) and N.D. -- 235 ppm (Trubyte Bioblend), respectively. (author)

  18. Cooling history of the Sanbagawa metamorphic belt inferred from fission track zircon ages

    Science.gov (United States)

    Shinjoe, H.; Tagami, T.

    1994-12-01

    The Sanbagawa metamorphic belt in central Shikoku, Japan, is a classic example of a high-pressure, intermediate facies series metamorphic belt. The lowest structural horizon of the Sanbagawa belt exposed in central Shikoku is the Oboke unit and this is overlain by the Besshi unit, which contains high-grade mineral zones. Seven fission track (FT) zircon ages were obtained from five fractions of felsic igneous pebbles in conglomerate, the matrix schist of conglomerate and an intercalated psammitic schist from the Oboke unit. The ages are in the range 56-69 Ma and are younger than 40Ar/ 39Ar ages previously reported from the Oboke unit (70-77 Ma). These concordant grain ages are interpreted as being post-metamorphic cooling ages because the samples analyzed are composed of zircon crystals of igneous and various detrital origins and, therefore, of variable provenance age. The cooling rate of the Oboke unit is less than 8°C/Ma, which is lower than that obtained for the Besshi unit. Our results of FT zircon dating are close to those of the melange zone of the Northern (Cretaceous) Shimanto belt (ca. 65 Ma). This suggests that the underplating of the high-pressure type Sanbagawa metamorphic rock occurred contemporaneously within the same subduction system as the growth of the Shimanto accretionary complex.

  19. Exhumation history of the NW Indian Himalaya revealed by fission track and 40Ar/39Ar ages

    Science.gov (United States)

    Schlup, Micha; Steck, Albrecht; Carter, Andrew; Cosca, Michael; Epard, Jean-Luc; Hunziker, Johannes

    2011-01-01

    New fission track and Ar/Ar geochronological data provide time constraints on the exhumation history of the Himalayan nappes in the Mandi (Beas valley) — Tso Morari transect of the NW Indian Himalaya. Results from this and previous studies suggest that the SW-directed North Himalayan nappes were emplaced by detachment from the underthrusted upper Indian crust by 55 Ma and metamorphosed by ca. 48–40 Ma. The nappe stack was subsequently exhumed to shallow upper crustal depths (

  20. Identification of the source of manufacture of obsidian through the dating with the method of fission track

    International Nuclear Information System (INIS)

    Arias, C.; Bigazzi, G.; Bonadonna, F.P.; Radi, G.; Bernardes, C.; Hadler Neto, J.C.; Lattes, C.M.G.; Araya, A.M.O.; Oliveira, J.X.

    1986-01-01

    Identification of the source of manufacture of obsidian through the dating with the method of fission track. After a brief description of fission track dating method and of the problems related to its application to volcanic glasses, we show and discuss data about obsidians of geological origin from Mediterranean basin and Latin America and of archaeological origin found in prehistoric sites from Italian peninsula. The analysis of the results shows the excellent performance of fission track method to identify the provenance of obsidians of archaeological origin, provided important constributions both from the methodological pointo of view-excellent agreement between the two correction techniques of apparent ages, size-correction technique and plateau age -, as from the archaeological point of view - we could identify four possible sources of provenance in Italy, the obsidian from Monte Arci, Sardinia, the obsidian from Pahnarola island, the obsidian from Gabelloto, Lipari island and the obsidian from Balata dei Turchi, Pantelleria island; and it ca be shown that Lipari obsidian began to be used at a very antique phase of neolithic period. The data about Latin American samples, though fragmented, constitute in an inicial study promissing perpectives as it can be observed by the comparisions made with the data published by others authors about geologic and archaeologic samples from the same area. (Author) [pt

  1. Fission-track dating of South American natural glasses: an overview

    International Nuclear Information System (INIS)

    Bigazzi, G.; Hadler Neto, J.C.; Iunes, P.J.; Osorio Araya, A.M.

    2005-01-01

    Although many glass-bearing horizons can be found in South American volcanic complexes or sedimentary series, only a relatively few tephra and obsidian-bearing volcanic fields have been studied using the fission-track (FT) dating method. Among them, the volcanics located in the Sierra de Guamani (east of Quito, Ecuador) were studied by several authors. Based upon their ages, obsidians group into three clusters: (1) very young obsidians, ∼0.2Ma old (2) intermediate-age obsidians, ∼0.4-∼0.8Ma old, and (3) older obsidians, ∼1.4-∼1.6Ma old. The FT method is also an efficient alternative technique for identification of the sources of prehistoric obsidian artefacts. Provenance studies carried out in South America have shown that the Sierra de Guamani obsidian occurrences were important sources of raw material for tool making during pre-Columbian times. Glasses originated from these sources were identified in sites distributed over relatively wide areas of Ecuador and Colombia. Only a few systematic studies on obsidians in other sectors were carried out. Nevertheless, very singular glasses have been recognised in South America, such as Macusanite (Peru) and obsidian Quiron (Argentina), which are being proposed as additional reference materials for FT dating. Analyses of tephra beds interstratified with sedimentary deposits revealed the performance of FT dating in tephrochronological studies. A remarkable example is the famous deposit outcropping at Farola Monte Hermoso, near Bahia Blanca (Buenos Aires Province), described for the first time by the middle of the 19th century by Charles Darwin. Considering the large number of volcanic glasses that were recognised in volcanic complexes and in sedimentary series, South America is a very promising region for the application of FT dating. The examples given above show that this technique may yield important results in different disciplinary fields

  2. Dating by fission tracers of some metamorphic rocks within the city of Rio de Janeiro

    International Nuclear Information System (INIS)

    Fonseca, A.C.; Poupeau, G.

    1984-01-01

    Fission-Track (FT) ages were measured in apatites from metamorphic rocks outcropping within the city of Rio de Janeiro. One apatite presented a 'substraction age' of 124 + - 10 my (2σ) and a second one a 'plateau age' of 117 + - 5 my. These ages are supposed to be related to the isostatic uplift related to the opening of the South-Atlantic Ocean. A younger plateau age of 85 + - 5 my might possibly be related to a later readjustment phase. Based on these and Fonseca et al. (1984) results, a cooling history for the rocks in Rio de Janeiro city is proposed. (Author) [pt

  3. A novel room temperature-induced chemical etching (RTCE) technique for the enlargement of fission tracks in Lexan polycarbonate SSNTD

    International Nuclear Information System (INIS)

    Chavan, Vivek; Kalsi, P.C.; Manchanda, V.K.

    2011-01-01

    The chemical or electrochemical etching is an essential step to enlarge the ion-induced latent tracks in solid state nuclear track detectors (SSNTDs). In these methods, above ambient temperatures (∼60 o C) and moderately high concentrations of alkali are required for about 1-2 h to enlarge the latent tracks. Microwave induced chemical etching method is reported to reduce the etching time for alpha tracks from 3 to 4 h to 25 min for CR-39 detector. In the present work, a room temperature-induced chemical etching employing ethanolamine as a new etchant has been investigated for the first time to enlarge the fission tracks in Lexan polycarbonate SSNTD. The tracks developed in the Lexan detectors etched at room temperature using ethanolamine are compared with those etched with routinely used chemical etching (CE) technique in 6 N NaOH at 60 o C. The bulk etch and track etch rates are also reported. The detection efficiency of RTCE method is determined and compared with that of CE method. The RTCE technique is found to be simple, fast and convenient.

  4. Erosional history of the Prydz Bay sector of East Antarctica from detrital apatite and zircon geo- and thermochronology multidating

    Science.gov (United States)

    Tochilin, Clare J.; Reiners, Peter W.; Thomson, Stuart N.; Gehrels, George E.; Hemming, Sidney R.; Pierce, Elizabeth L.

    2012-11-01

    Approximately 98% of East Antarctica is covered by the East Antarctic Ice Sheet (EAIS), which has covered parts of the continent since the early Oligocene (34 Ma) and obscures evidence about the region's tectonic and erosional history. To better constrain the subglacial record, we analyzed geo- and thermochronologic dates of Oligocene-Quaternary sediments from Prydz Bay, which drains ˜16% of the EAIS. We used multidating techniques, measuring U-Pb, fission track, and (U-Th)/He dates on apatite and zircon grains and40Ar/39Ar dates on hornblende grains to determine crystallization and cooling ages. Apatite and zircon U-Pb dates and hornblende40Ar/39Ar dates are dominantly ˜500 Ma, recording Pan-African metamorphism and magmatism. Zircon fission track dates record cooling at ˜250-300 Ma and ˜120 Ma from Permian-Triassic (300-201 Ma) rifting and Cretaceous (120 Ma) magmatic resetting. Mean apatite fission track dates decrease from ˜280-210 Ma in early Oligocene samples, with lag times decreasing from ˜250-180 My, indicating increasing erosion rates. Miocene-Quaternary (10.7-0 Ma) samples show a smaller range from ˜180 to ˜150 Ma. Youngest measured apatite He ages also decrease from ˜100 Ma to ˜25 Ma in Oligocene-Miocene samples. These results indicate increasing erosion rates (0.2 km/My) in catchments draining to Prydz Bay in the early Oligocene, with slower erosion since the late Miocene. This erosion was likely achieved by glacial incision into pre-existing valleys, reaching depths of ˜2.8-3.0 km by the late Miocene. This is consistent with EAIS models showing a transition to less erosive, cold-based conditions following the mid-Miocene climatic optimum.

  5. Mesozoic-Cenozoic evolution of the Zoige depression in the Songpan-Ganzi flysch basin, eastern Tibetan Plateau: Constraints from detrital zircon U-Pb ages and fission-track ages of the Triassic sedimentary sequence

    Science.gov (United States)

    Tang, Yan; Zhang, Yunpeng; Tong, Lili

    2018-01-01

    The Zoige depression is an important depocenter within the northeast Songpan-Ganzi flysch basin, which is bounded by the South China, North China and Qiangtang Blocks and forms the northeastern margin of the Tibetan Plateau. This paper discusses the sediment provenance and Mesozoic-Cenozoic evolution of the Zoige depression in the Songpan-Ganzi flysch basin, eastern Tibetan Plateau, using the detrital zircon U-Pb ages and apatite fission-track data from the Middle to Late Triassic sedimentary rocks in the area. The U-Pb ages of the Middle to Late Triassic zircons range from 260-280 Ma, 429-480 Ma, 792-974 Ma and 1800-2500 Ma and represent distinct source region. Our new results demonstrate that the detritus deposited during the Middle Triassic (Ladinian, T2zg) primarily originated from the Eastern Kunlun and North Qinling Orogens, with lesser contributions from the North China Block. By the Late Triassic (early Carnian, T3z), the materials at the southern margin of the North China Block were generally transported westward to the basin along a river network that flowed through the Qinling region between the North China and South China Blocks: this interpretation is supported by the predominance of the bimodal distribution of 1.8 Ga and 2.5 Ga age peaks and a lack of significant Neoproterozoic zircon. Since the Late Triassic (middle Carnian, T3zh), considerable changes have occurred in the source terranes, such as the cessation of the Eastern Kunlun Orogen and North China Block sources and the rise of the northwestern margin of the Yangtze Block and South Qinling Orogen. These drastic changes are compatible with a model of a sustained westward collision between the South China and North China Blocks during the late Triassic and the clockwise rotation of the South China Block progressively closed the basin. Subsequently, orogeny-associated folds have formed in the basin since the Late Triassic (late Carnian), and the study area was generally subjected to uplifting and

  6. Study of uranium mineralization in rock samples from marwat range bannu basin by fission track analysis technique

    International Nuclear Information System (INIS)

    Qureshi, A.Z.; Ullah, K.; Ullah, N.; Akram, M.

    2004-07-01

    The Geophysics Division, Atomic Energy Minerals Centre (AEMC), Lahore has planned a uranium exploration program in Marwat Range, Bannu Basin. In this connection 30 thin sections of rock samples, collected from four areas; namely, Darra Tang, Simukili, Karkanwal and Sheikhillah from Marwat Range, and one from Salt Range were provided to Nuclear Geology Group of Physics Research Division, PINSTECH for the study of nature and mechanism of uranium mineralization These studies are aimed to help in designing uranium exploration strategy by providing the loci of uranium sources in the Marwat and Salt Ranges. The samples have been studied using fission track analysis technique. (author)

  7. Measurement of the energy spectrum of {sup 252}Cf fission fragments using nuclear track detectors and digital image processing

    Energy Technology Data Exchange (ETDEWEB)

    Espinosa, G.; Golzarri, J. I. [UNAM, Instituto de Fisica, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Castano, V. M. [UNAM, Centro de Fisica Aplicada y Tecnologia Avanzada, Boulevard Juriquilla 3001, Santiago de Queretaro, 76230 Queretaro (Mexico); Gaso, I. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Mena, M.; Segovia, N. [UNAM, Instituto de Geofisica, Circuito de la Investigacion Cientifica, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2010-02-15

    The energy spectrum of {sup 252}Cf fission fragments was measured using nuclear track detectors and digital image analysis system. The detection material was fused silica glass. The detectors were chemically etched in an 8% HF solution. After experimenting with various etching time, it was found that the best resolution of the track diameter distribution was obtained after 30 minutes of etching. Both Gaussian and Lorentzian curves were fit to the track diameter distribution histograms and used to determine the basic parameters of the distribution of the light (N{sub L}) and heavy (N{sub H}) formed peaks and the minimum of the central valley (N{sub V}). Advantages of the method presented here include the fully-automated analysis process, the low cost of the nuclear track detectors and the simplicity of the nuclear track method. The distribution resolution obtained by this method is comparable with the resolution obtained by electronic analysis devices. The descriptive variables calculated were very close to those obtained by other methods based on the use of semiconductor detectors. (Author)

  8. New fission-track ages of mio-pliocene tuffs in the Sierras Pampeanas and Precordillera of Argentina

    International Nuclear Information System (INIS)

    Tabbutt, K.; Naeser, C.W.; Jordan, T.E.; Cerveny, P.F.

    1989-01-01

    Fission-track dates were determined for 18 volcanic tuff horizons located in nine Neogene foreland basin sequences distributed throughout the Precordillera and Sierras Pampeanas of Northwestern Argentina, an area of nearly horizontal subduction. These and other data indicate that a lower age limit for the sedimentary sequences studied is approximately 17 Ma. Therefore these fission-track dates constrain both the history of volcanic activity and the time of deposition in several foreland basins from the middle Miocene to Recent. Although the dates range from 3.6±0.8 Ma to 17.0±1.9 Ma, there is a marked increase in the number of ashes younger than 9 Ma. This implies that two distinct episodes of volcanic activity affected the region. The source of some of these tuffs is unknown but they are probably limited to the 'flat-slab' region between 27 deg and 32 deg S. Tuffs at Rio Blanco and Santa Florentina that are spatially associated with the Mogotes dacite domes of the Famatina Range represented magmatism bracketed from about 7 to 4 Ma in the region underlain by the flat-subducted plate. The stratigraphic relations in the basins show that the faulting that uplifted Sierra de Famatina was contemporaneous with the volcanism which reached the surface along the bounding faults. (Author) [es

  9. Detrital fission-track-compositional signature of an orogenic chain-hinterland basin system: The case of the late Neogene Quaternary Valdelsa basin (Northern Apennines, Italy)

    Science.gov (United States)

    Balestrieri, M. L.; Benvenuti, M.; Tangocci, F.

    2013-05-01

    Detrital thermochronological data collected in syn-tectonic basin deposits are a promising tool for deciphering time and processes of the evolution of orogenic belts. Our study deals with the Valdelsa basin, one of the wider basins of central Tuscany, Italy. The Valdelsa basin is located at the rear of the Northern Apennines, a collisional orogen whose late Neogene Quaternary development is alternatively attributed to extensional and compressional regimes. These contrasting interpretations mostly rely on different reconstructions of the tectono-sedimentary evolution of several basins formed at the rear of the chain since the late Tortonian. Here, we explore the detrital thermochronological-compositional signature of tectonic and surface processes during the Valdelsa basin development. For this aim, detrital apatite fission-track analysis of 21 sand samples from the latest Messinian Gelasian fluvial to shallow marine basin deposits, has been accompanied by a clast composition analysis of 7 representative outcrops of the conglomerate facies. The grain-age distributions of the sediment samples are generally characterized by two distinct components, one younger peak (P1) varying between 5.5 ± 2.8 and 9.5 ± 1.0 Ma and one older peak (P2) varying from 15.0 ± 8.0 to 41.0 ± 10 Ma. By comparison with some bedrock ages obtained from the E-NE basin shoulder, we attributed the P2 peak to the Ligurian Units and the P1 peak to the Macigno Formation (Tuscan Units). These units are arranged one upon the other in the complex nappe pile forming the Northern Apennines orogen. While the gravel composition indicates a predominant feeding from the Ligurian units all along the sedimentary succession with a subordinate occurrence of Macigno pebbles slightly increasing upsection, the P1 peak is present even in the oldest collected sandy sediments. The early P1 occurrence reveals that the Macigno was exposed in the E-NE basin shoulder since at least the latest Messinian-early Zanclean

  10. $\\bar{p}$-Induced Fission Studies with Plastic Track Detectors Using 4$\\pi$-Geometry

    CERN Multimedia

    2002-01-01

    % EMU20 \\\\ \\\\ The annihilation of a stopped antiproton on the surface of a target nucleus produces on the average five pions with a mean energy of 230~MeV. The high excitation of the nuclei with low angular momentum transfer can also be achieved by direct pion-nucleus interactions. The fission probabilities of highly excited nuclei can be explained on the basis of high energy limit of statistical theory. Previously the binary fission and higher multiplicity break-up of various nuclei caused by the absorption of pions has been studied by our group. The mechanism of nuclear excitation may still be the same when an antiproton annihilates in a nucleus and produces pions. It would be interesting to see whether the $\\bar{p}$ annihilation produces high enough excitation energies for nuclear phase-transition to take place. If so, then the fragmentation would overwhelm binary and ternary fission process. \\\\ \\\\The use of a highly sensitive plastic detector, CR-39, was made by our group in a number of studies involving ...

  11. Dating by fission track method: study of neutron dosimetry with natural uranium thin films; Datacao com o metodo dos tracos de fissao: estudo da dosimetria de neutrons com filmes finos de uranio natural

    Energy Technology Data Exchange (ETDEWEB)

    Iunes, P.J.

    1990-06-01

    Fission track dating is described, focalizing the problem of the decay constant for spontaneous fission of {sup 238} U and the use of neutron dosimetry in fission track analysis. Experimental procedures using thin films of natural uranium as neutron dosimeters and its results are presented. The author shows a intercomparison between different thin films and between the dosimetry with thin film and other dosimetries. (M.V.M.). 52 refs, 12 figs, 9 tabs.

  12. A helium-based model for the effects of radiation damage annealing on helium diffusion kinetics in apatite

    Science.gov (United States)

    Willett, Chelsea D.; Fox, Matthew; Shuster, David L.

    2017-11-01

    Widely used to study surface processes and the development of topography through geologic time, (U-Th)/He thermochronometry in apatite depends on a quantitative description of the kinetics of 4He diffusion across a range of temperatures, timescales, and geologic scenarios. Empirical observations demonstrate that He diffusivity in apatite is not solely a function of temperature, but also depends on damage to the crystal structure from radioactive decay processes. Commonly-used models accounting for the influence of thermal annealing of radiation damage on He diffusivity assume the net effects evolve in proportion to the rate of fission track annealing, although the majority of radiation damage results from α-recoil. While existing models adequately quantify the net effects of damage annealing in many geologic scenarios, experimental work suggests different annealing rates for the two damage types. Here, we introduce an alpha-damage annealing model (ADAM) that is independent of fission track annealing kinetics, and directly quantifies the influence of thermal annealing on He diffusivity in apatite. We present an empirical fit to diffusion kinetics data and incorporate this fit into a model that tracks the competing effects of radiation damage accumulation and annealing on He diffusivity in apatite through geologic time. Using time-temperature paths to illustrate differences between models, we highlight the influence of damage annealing on data interpretation. In certain, but not all, geologic scenarios, the interpretation of low-temperature thermochronometric data can be strongly influenced by which model of radiation damage annealing is assumed. In particular, geologic scenarios involving 1-2 km of sedimentary burial are especially sensitive to the assumed rate of annealing and its influence on He diffusivity. In cases such as basement rocks in Grand Canyon and the Canadian Shield, (U-Th)/He ages predicted from the ADAM can differ by hundreds of Ma from those

  13. Uranium content of coal ashes from Southern Brazil coal fueled power stations, by the fission track registration technique

    International Nuclear Information System (INIS)

    Morales, R.K.

    1981-01-01

    The feasibility of the application of the fission track registration technique for the determination of uranium in coal ashes was shown. The wet method was employed using as detector the Makrofol KG=10 μm, manufactured by Bayer. The coal ashes were originated from coal-fueled power stations localized in Southern Brazil. The results obtained ranged from 10 to 27 mg U/kg. Since the total error variation was from 18,4% to 23,8%, the method used was considered excellent. The determination of the uranium content in coal ashes is of considerable interest in environmental control in power stations, in their vicinity and wherever these ashes are used or stored. The technique used is the work proved to be very appropriate for the purpose aimed at. (Author) [pt

  14. Zircon fission-track technique: a laboratory procedure adopted at the Institute of Geology, Academy of Sciences of the Czech Republic, v.v.i

    Czech Academy of Sciences Publication Activity Database

    Murakami, M.; Svojtka, Martin

    2007-01-01

    Roč. 20, - (2007), s. 13-19 ISSN N R&D Projects: GA MŠk 1K05030 Institutional research plan: CEZ:AV0Z30130516 Keywords : fission-track * zircon * Institute of Geology AS CR, v. v. i. Subject RIV: DB - Geology ; Mineralogy

  15. Detrital zircon fission-track thermochronology and magnetic fabric of the Amaga Formation (Colombia): Intracontinental deformation and exhumation events in the northwestern Andes

    Czech Academy of Sciences Publication Activity Database

    Piedrahita, V. A.; Bernet, M.; Chadima, Martin; Sierra, G. M.; Marín-Cerón, M. I.; Toro, G. E.

    2017-01-01

    Roč. 356, JUL 1 2017 (2017), s. 26-42 ISSN 0037-0738 Institutional support: RVO:67985831 Keywords : Panama-Choco Block * Northern Andean Block * Amaga Formation * zircon fission track * anisotropy of magnetic susceptibility Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 2.373, year: 2016

  16. The lunar apatite paradox.

    Science.gov (United States)

    Boyce, J W; Tomlinson, S M; McCubbin, F M; Greenwood, J P; Treiman, A H

    2014-04-25

    Recent discoveries of water-rich lunar apatite are more consistent with the hydrous magmas of Earth than the otherwise volatile-depleted rocks of the Moon. Paradoxically, this requires H-rich minerals to form in rocks that are otherwise nearly anhydrous. We modeled existing data from the literature, finding that nominally anhydrous minerals do not sufficiently fractionate H from F and Cl to generate H-rich apatite. Hydrous apatites are explained as the products of apatite-induced low magmatic fluorine, which increases the H/F ratio in melt and apatite. Mare basalts may contain hydrogen-rich apatite, but lunar magmas were most likely poor in hydrogen, in agreement with the volatile depletion that is both observed in lunar rocks and required for canonical giant-impact models of the formation of the Moon.

  17. Discovery of Naturally Etched Fission Tracks and Alpha-Recoil Tracks in Submarine Glasses: Reevaluation of a Putative Biosignature for Earth and Mars

    Directory of Open Access Journals (Sweden)

    Jason E. French

    2016-01-01

    Full Text Available Over the last two decades, conspicuously “biogenic-looking” corrosion microtextures have been found to occur globally within volcanic glass of the in situ oceanic crust, ophiolites, and greenstone belts dating back to ~3.5 Ga. These so-called “tubular” and “granular” microtextures are widely interpreted to represent bona fide microbial trace fossils; however, possible nonbiological origins for these complex alteration microtextures have yet to be explored. Here, we reevaluate the origin of these enigmatic microtextures from a strictly nonbiological standpoint, using a case study on submarine glasses from the western North Atlantic Ocean (DSDP 418A. By combining petrographic and SEM observations of corrosion microtextures at the glass-palagonite interface, considerations of the tectonic setting, measurement of U and Th concentrations of fresh basaltic glass by ICP-MS, and theoretical modelling of the present-day distribution of radiation damage in basaltic glass caused by radioactive decay of U and Th, we reinterpret these enigmatic microtextures as the end product of the preferential corrosion/dissolution of radiation damage (alpha-recoil tracks and fission tracks in the glass by seawater, possibly combined with pressure solution etch-tunnelling. Our findings have important implications for geomicrobiology, astrobiological exploration of Mars, and understanding of the long-term breakdown of nuclear waste glass.

  18. Laboratory-Scale Bismuth Phosphate Extraction Process Simulation To Track Fate of Fission Products

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R. JEFFREY; Lindberg, Michael J.; Jones, Thomas E.; Schaef, Herbert T.; Krupka, Kenneth M.

    2007-02-28

    Recent field investigation that collected and characterized vadose zone sediments from beneath inactive liquid disposal facilities at the Hanford 200 Areas show lower than expected concentrations of a long-term risk driver, Tc-99. Therefore laboratory studies were performed to re-create one of the three processes that were used to separate the plutonium from spent fuel and that created most of the wastes disposed or currently stored in tanks at Hanford. The laboratory simulations were used to compare with current estimates based mainly on flow sheet estimates and spotty historical data. Three simulations of the bismuth phosphate precipitation process show that less that 1% of the Tc-99, Cs-135/137, Sr-90, I-129 carry down with the Pu product and thus these isotopes should have remained within the metals waste streams that after neutralization were sent to single shell tanks. Conversely, these isotopes should not be expected to be found in the first and subsequent cycle waste streams that went to cribs. Measurable quantities (~20 to 30%) of the lanthanides, yttrium, and trivalent actinides (Am and Cm) do precipitate with the Pu product, which is higher than the 10% estimate made for current inventory projections. Surprisingly, Se (added as selenate form) also shows about 10% association with the Pu/bismuth phosphate solids. We speculate that the incorporation of some Se into the bismuth phosphate precipitate is caused by selenate substitution into crystal lattice sites for the phosphate. The bulk of the U daughter product Th-234 and Np-237 daughter product Pa-233 also associate with the solids. We suspect that the Pa daughter products of U (Pa-234 and Pa-231) would also co-precipitate with the bismuth phosphate induced solids. No more than 1 % of the Sr-90 and Sb-125 should carry down with the Pu product that ultimately was purified. Thus the current scheme used to estimate where fission products end up being disposed overestimates by one order of magnitude the

  19. Sequential fission process observed in the reaction (16.7 MeV/u) 238U + nat.Au using mica as dielectric track detector

    International Nuclear Information System (INIS)

    Shahzad, Muhammad Ikram; Qureshi, Imtinan Elahi; Manzoor, Shahid; Khan, Hameed Ahmed

    1999-01-01

    The evidence of sequential fission has been found in the heavy-ion reaction (16.7 MeV/u) 238 U + nat. Au, using muscovite mica as Dielectric Track Detector (DTD) placed in a 2π-geometry configuration. The reaction products originating from the interactions of 238 U ions with the atoms of gold were registered in the detector in the form of tracks and identified for performing a detailed kinematical analysis. For this purpose the spherical polar coordinates of the correlated tracks of the multipronged events have been analyzed on an event-by-event basis. Automatic, semi-automatic and manual measuring methods have been employed to collect and manipulate the track data. The known characteristics of binary and ternary events observed in the reaction have been used for the calibration of the detectors. The computed masses, Q-values and relative velocities of the reaction products determined in this analysis are compared with theoretical predictions based on sequential fission process. Agreement within one standard deviation with respect to the experimental values has been found for the majority of analyzed events. Therefore, it is concluded that three particles in the exit channel of the reaction are produced in two successive steps. In the first step of the reaction, two intermediate nuclei are formed as a result of an inelastic collision between projectile and target atoms while in the second step the fission of one of the intermediate nuclei of the previous step takes place. Furthermore no proximity effects have been observed

  20. Late cenozoic tectonic and geomorphic evolution of the Patagonian Andes between 42oS and 52oS, southern Chile assessed using fission-track thermochronology

    International Nuclear Information System (INIS)

    Thomson, S.N; Herve, F; Stockhert, B.; Brix, M.R.; Adriasola, A

    2001-01-01

    Fission-track (FT) analysis has been applied in the Patagonian Andes of southern Chile to assess the late Cenozoic geomorphic and tectonic response of the overriding plate to subduction of the Chile rise active oceanic spreading centre (Thomson et al., 2001). The timing and nature of tectonic uplift and denudation along the southern parts of the major transpression intra-arc Liquine-Ofqui fault (LOF) system have also been investigated (Thomson, 2001, submitted). Results from 130 FT ages (72 zircon and 58 apatite ages) and 39 apatite track length measurements reveal initiation of rapid cooling and denudation at ca. 30 Ma at the western margin of southern continental South America. This was followed by a ca. 200km eastward migration of the locus of maximum denudation to the position of the present day topographic divide between ca. 30 Ma and ca. 12 to 10 Ma. East of the Andean divide less than 3 km of denudation has occurred since the Late Cretaceous. Enhanced denudation is interpreted to be the result of increased tectonic uplift driven by a large increase in convergence rates at ca. 28 to 26 Ma that triggered orographically enhanced precipitation on the west-side of the Patagonian Andes allowing increased erosion by fluvial incision and mass transport processes. The eastward migration of the locus of maximum denudation can be related to either coeval eastward migration of the retro-arc deformation front, the effects of subduction erosion in the overriding plate at the Peru-Chile trench or shallowing of the angle of subduction. Away from the influence of the LOF the process of spreading centre subduction and collision itself coincides with an overall slow-down in denudation rates in the overriding plate most likely caused by a major reduction in the main tectonic force driving tectonic uplift in the upper plate to subduction. In contrast to the Andes south of ca. 46 o S, increased cooling and denudation related to transpression induced rock uplift and erosion along

  1. Discussion on terminology, anisotropy, and interprocedural cross-checks of fission track ages of zircon

    International Nuclear Information System (INIS)

    Suzuki, Masao

    1984-01-01

    Technical terms should clearly be distinguished for procedural data collection and for statistical data calculation. Available procedural variations are defined and described. According to observation of anisotropic etching and counting especially among lower spontaneous track density zircons, explanatory terms are described; and the relationship between total (mainly on-anisotropic etching-dependent) counting efficiency (etasub(EStotal)) and spontaneous track density (rhosub(s)) is deduced as etasub(EStotal) = 0.123 log rhosub(s) + 0.220. To counter contradictory opinions on possible procedural variations, 1-set-4-aliquot preparation and processing technique is introduced for interprocedural cross-checks of resulting ages, and preliminary results of its application to zircon from the Fish Canyon Tuff (K-Ar ages, 27.9 +- 0.7 Ma, and F.T. age, 28.4 +- 0.7 Ma) are reported. Results of 2pi Population, S2piES-I2piED, and S4piES-I2piED (External Detector) procedures range from 32.4 to 26.6 Ma. After correcting their intrinsic procedural defects, ages become within the range of 28.2 - 27.9 Ma. It is suggested that appropriate alternative(s) among possible procedural variations are selected for the particular geochronological background of zircon specimens, through extensive work on interprocedural cross-checks of resulting ages. In the case of younger or lower spontaneous track density zircon, advantages and dating limits (rhosub(s) 6 t.cm -2 ) of the S2piES-I2piES procedure, are especially referred and suggested. (author)

  2. Determination of the uranium concentration in samples of raw, retorted and spent shale from Irati, Parana-Brazil, by the fission track registration technique

    International Nuclear Information System (INIS)

    Cabral, R.G.

    1981-02-01

    The feasibility of the determination of uranium in oil shale, by the fission track registration technique is studied. The wet and dry methods were employed, using a Bayer policarbonate, Makrofol KG, as detector. It was created a new variant of the dry method. The fission track registration technique was used in samples of raw, retorted and spent shale from Irati, Parana in Brazil, 16 μg U/g, 20 μg U/g and 20μg U/g were found, respectively, with a total error ranging from 19% to 20%. Some experimental results were included for illustration and comparison. The feasibility of the determination of uranium in oil shale from Irati was verified. (Author) [pt

  3. Trace quantities of uranium in some indian chewing tobaccos as determined by fission track analysis

    International Nuclear Information System (INIS)

    Rana, N.P.S.; Singh, P.; Azam, A.; Naqvi, A.H.; Srivastava, D.S.

    1996-01-01

    The sandwiched pellet technique using Makrofol-E plastic track detectors has been employed to determine trace quantities of uranium in nine brands of flavored chewing tobaccos consumed by the Indian population. In this technique the nuclear reaction, 235 U(n,f), is used for the quantitative estimation of uranium. The maximum value of uranium (1.88 ppm) has been found in raw tobacco leaves (Surti), while the minimum (0.13 ppm) in Tulsi (Double Zero brand). Other seven brands showed intermediate values of U-contents which are also reported in this paper. These values are compared with the U-contents reported in the literature for other forms of tobaccos. (author). 9 refs., 2 figs., 1 tab

  4. Iodine immobilization in apatites

    International Nuclear Information System (INIS)

    Audubert, F.; Lartigue, J.E.

    2000-01-01

    In the context of a scientific program on long-lived radionuclide conditioning, a matrix for iodine 129 immobilization has been studied. A lead vanado-phosphate apatite was prepared from the melt of lead vanado-phosphate Pb 3 (VO 4 ) 1.6 (PO 4 ) 0.4 and lead iodide PbI 2 in stoichiometric proportions by calcination at 700 deg. C during 3 hours. Natural sintering of this apatite is not possible because the product decomposition occurs at 400 deg. C. Reactive sintering is the solution. The principle depends on the coating of lead iodide with lead vanado-phosphate. Lead vanado-phosphate coating is used as iodo-apatite reactant and as dense covering to confine iodine during synthesis. So the best condition to immobilize iodine during iodo-apatite synthesis is a reactive sintering at 700 deg. C under 25 MPa. We obtained an iodo-apatite surrounded with dense lead vanadate. Leaching behaviour of the matrix synthesized by solid-solid reaction is under progress in order to determine chemical durability, basic mechanisms of the iodo-apatite alteration and kinetic rate law. Iodo-apatite dissolution rates were pH and temperature dependent. We obtained a rate of 2.5 10 -3 g.m -2 .d -1 at 90 deg. C in initially de-ionised water. (authors)

  5. Mesozoic - Cenozoic tectonic evolution of southwestern Tian Shan: Evidence from detrital zircon U/Pb and apatite fission track ages of the Ulugqat area, Northwest China

    NARCIS (Netherlands)

    Yang, W.; Jolivet, M.; Dupont-Nivet, G.; Guo, Z.

    2013-01-01

    The Late Tertiary tectonic and topographic evolution of the Tian Shan Range has beenwidely studied as it represents a key example of active intra-continentalmountain belts. Recent studies have shown that both the general tectonic framework of Tian Shan and some of its actual topographic features

  6. Trace-element and Nd-isotope systematics in detrital apatite of the Po river catchment: Implications for provenance discrimination and the lag-time approach to detrital thermochronology

    Science.gov (United States)

    Malusà, Marco G.; Wang, Jiangang; Garzanti, Eduardo; Liu, Zhi-Chao; Villa, Igor M.; Wittmann, Hella

    2017-10-01

    Detrital thermochronology is often employed to assess the evolutionary stage of an entire orogenic belt using the lag-time approach, i.e., the difference between the cooling and depositional ages of detrital mineral grains preserved in a stratigraphic succession. The impact of different eroding sources to the final sediment sink is controlled by several factors, including the short-term erosion rate and the mineral fertility of eroded bedrock. Here, we use apatite fertility data and cosmogenic-derived erosion rates in the Po river catchment (Alps-Apennines) to calculate the expected percentage of apatite grains supplied to the modern Po delta from the major Alpine and Apenninic eroding sources. We test these predictions by using a cutting-edge dataset of trace-element and Nd-isotope signatures on 871 apatite grains from 14 modern sand samples, and we use apatite fission-track data to validate our geochemical approach to provenance discrimination. We found that apatite grains shed from different sources are geochemically distinct. Apatites from the Lepontine dome in the Central Alps show relative HREE enrichment, lower concentrations in Ce and U, and higher 147Sm/144Nd ratios compared to apatites derived from the External Massifs. Derived provenance budgets point to a dominant apatite contribution to the Po delta from the high-fertility Lepontine dome, consistent with the range independently predicted from cosmonuclide and mineral-fertility data. Our results demonstrate that the single-mineral record in the final sediment sink can be largely determined by high-fertility source rocks exposed in rapidly eroding areas within the drainage. This implies that the detrital thermochronology record may reflect processes affecting relatively small parts of the orogenic system under consideration. A reliable approach to lag-time analysis would thus benefit from an independent provenance discrimination of dated mineral grains, which may allow to proficiently reconsider many

  7. Sequential fission process observed in the reaction (16.7 MeV/u) {sup 238}U + {sup nat.}Au using mica as dielectric track detector

    Energy Technology Data Exchange (ETDEWEB)

    Shahzad, Muhammad Ikram; Qureshi, Imtinan Elahi; Manzoor, Shahid; Khan, Hameed Ahmed

    1999-01-04

    The evidence of sequential fission has been found in the heavy-ion reaction (16.7 MeV/u) {sup 238}U + {sup nat.}Au, using muscovite mica as Dielectric Track Detector (DTD) placed in a 2{pi}-geometry configuration. The reaction products originating from the interactions of {sup 238}U ions with the atoms of gold were registered in the detector in the form of tracks and identified for performing a detailed kinematical analysis. For this purpose the spherical polar coordinates of the correlated tracks of the multipronged events have been analyzed on an event-by-event basis. Automatic, semi-automatic and manual measuring methods have been employed to collect and manipulate the track data. The known characteristics of binary and ternary events observed in the reaction have been used for the calibration of the detectors. The computed masses, Q-values and relative velocities of the reaction products determined in this analysis are compared with theoretical predictions based on sequential fission process. Agreement within one standard deviation with respect to the experimental values has been found for the majority of analyzed events. Therefore, it is concluded that three particles in the exit channel of the reaction are produced in two successive steps. In the first step of the reaction, two intermediate nuclei are formed as a result of an inelastic collision between projectile and target atoms while in the second step the fission of one of the intermediate nuclei of the previous step takes place. Furthermore no proximity effects have been observed.

  8. Hanford Apatite Treatability Test Report Errata: Apatite Mass Loading Calculation

    Energy Technology Data Exchange (ETDEWEB)

    Szecsody, James E.; Vermeul, Vincent R.; Williams, Mark D.; Truex, Michael J.

    2014-05-19

    The objective of this errata report is to document an error in the apatite loading (i.e., treatment capacity) estimate reported in previous apatite treatability test reports and provide additional calculation details for estimating apatite loading and barrier longevity. The apatite treatability test final report (PNNL-19572; Vermeul et al. 2010) documents the results of the first field-scale evaluation of the injectable apatite PRB technology. The apatite loading value in units of milligram-apatite per gram-sediment is incorrect in this and some other previous reports. The apatite loading in units of milligram phosphate per gram-sediment, however, is correct, and this is the unit used for comparison to field core sample measurements.

  9. Application of the dating by fission tracks to determine thermicity of basins within petroleum potentialities: example of Sbaa and Ahnet-North basins located in Western Saharan platform, Algeria

    International Nuclear Information System (INIS)

    Akkouche, M.

    2007-05-01

    The interpretation of old fundamental research works and the results obtained by this study based on: the analysis of apatite fission tracks (AFT), the burial evolution curves and the sequential analysis of outcrop section, as well as the curves of signal of gamma ray (GR) analysis from drilling wells, allow to precise that the geodynamic evolution of the studied Algerian sedimentary basins (Ahnet and Sbaa) have been occurred principally in the Paleozoic era. The analysis of burial evolution curves shows that during the Paleozoic period, the sedimentation is controlled by the tectonic subsidence, particularly at the end of Carboniferous in the favor of Ougarta folding. The curves indicate an uplift from the Permian to middle Jurassic, expressed by an important erosion of sedimentary series and is considered as a response of thermal convection of the Saharan platform followed by thermal subsidence. This can be explained by the halt motion of rift extension caused by the opening of the Atlantic Ocean. To bring the sequential analysis out, it appears that Ahnet and Sbaa basins present contrasted stratigraphic recordings, so much in time than in space, indicated the different effects from subsidence and erosions according to their sectors. In thermal point of view, temperatures are still moderate in Sbaa depression and favorite the preservation of organic matter and might generate hydrocarbons until now. However, these conditions are not similar to ones in the case of Ahnet basin. In the North part of Ahnet basin (MRS-1, MSL-1), the ages are around 50 Ma, attested that sedimentary layers have been sustained a post-Hercynian thermal phase. This phase could be estimated probably more than 100 C. This is also produced during the regional extension of the Triassic-Jurassic rifting. This episode could also be responsible of disappearance (total?) of pre-existence fission tracks in the Devonian layers of the well MSR-1, which exhibits at the depth 505 m under the Hercynian

  10. Summary of theory and techniques, sample selection and project organization for potassium-argon, rubidium-strontium and fission track dating and strontium isotope studies

    International Nuclear Information System (INIS)

    Adams, C.J.; Graham, I.J.; Seward, D.

    1987-02-01

    A brief outline is given of the theory and techniques of the potassium-argon, rubidium-strontium and fission-track dating methods and related isotope studies which are currently in use at the Institute of Nuclear Sciences, DSIR. Some limitations of each technique are set out in terms of age range and materials for dating, and the appropriate choice of various mineral and rock types and subsequent age interpretations are discussed. The organisation of project proposals and categories is described and procedures for sample submission and documentation are given

  11. Fission-track study of the uranium bio-geochemistry in carbonates of Bikini and Enewetak Atolls. Progress report, July 1, 1974--December 31, 1975

    International Nuclear Information System (INIS)

    Levy, Y.; Miller, D.S.; Friedman, G.M.; Goter, E.R.

    1975-09-01

    Major contributions during this contract period have been in developing an analytical procedure for Pu measurement, and in applying the developed procedures to determining the plutonium concentration and distribution in coral from the Bikini Atoll. In conjunction with these contributions, measurements using the fission-track method have been made of the uranium distribution and concentrations in several carbonate samples from drill cores obtained from the Runit Island Enewetak Atoll. Petrographic studies on these drill core samples have been made to correlate the uranium data with the mineralogical data

  12. Temporal constraints on the tectonic evolution of Sierra De Famatina, northwestern Argentina, using the fission-track method to date tuffs interbedded in synorogenic clastic sedimentary strata

    Energy Technology Data Exchange (ETDEWEB)

    Tabbutt, K.D. (Dartmouth College, Hanover, NH (USA))

    1990-07-01

    Fission-track dates from seven volcaniclastic units allow time constraints to be placed on synorogenic clastic strata exposed along the flanks of Sierra de Famatina, northwest Argentina. Four formations are exposed along the western margin of Sierra de Famatina. The El Abra conglomerate is composed of clasts eroded from the basement exposed just to the west of Cadena de Paiman. The El Buey Formation contains sediments probably derived from the Precordillera fold and thrust belt to the west. Fission-track dates give a maximum age of 6 Ma for the deposition of both of these formations. The El Durazno Formation, deposited between 6 and 4 Ma, contains proximal volcaniclastic and other clastic rocks derived from the core of Sierra de Famatina. The Santa Florentina conglomerate was derived from the rising Sierra de Famatina and deposited in the past 4 m.y. Sierra de Famatima probably became a positive topographic feature approximately 6 Ma. Prior to that time this region was receiving fine-grained sediments from a distal fold and thrust belt and conglomerates from local basement uplifts. Minor extrusive events (Mogote Formation) coincide both spatially and temporally with deformation along the major reverse faults that control the uplift of Sierra de Famatina. Minimum mean uplift rates calculated for Sierra de Famatina are 0.8 {plus minus} 0.1 mm/yr over a 6.8 m.y. interval.

  13. New Constraints for Tectono-Thermal Alpine Evolution of the Pyrenees: Combining Zircon Fission-Track and (U-Th)/He Analyses with Raman Spectrometry and In-Situ K-Ar Geochronology

    Science.gov (United States)

    Waldner, M.; Bellahsen, N.; Mouthereau, F.; Pik, R.; Bernet, M.; Scaillet, S.; Rosenberg, C.

    2017-12-01

    The pyrenean range was formed by the convergence of European and Iberian plates following the inversion of the Mesozoic rifting in the north of Pyrenees. In the Axial Zone, the collision caused an antiformal nappe-stacking of tectonic units. Recent studies pointed out the importance of pre-collision structural and thermal inheritance that may play a major role for orogeny such as: 1) Paleozoic Variscan inheritance; 2) Mesozoic rift-related high geothermal gradients, which are maintained during the onset of convergence in the North Pyrenean Zone. From a mineralogical point of view, pre-collision feldspars have been destabilized and influenced the development of alpine phyllonite in brittle-ductile conditions which suggests a weak crustal behavior during the formation of the orogenic wedge. Our aim is to get a better understanding of alpine deformation and exhumation by coupling different thermochronological, geochronological and thermometric methods. We document the thermal evolution of each tectonic unit by using low-temperature thermochronometers (Zircon Fission Tracks, U-Th/He on zircons including laser ablation profiles). Our data on vertical profiles combined to existing dataset on apatite allows to model alpine exhumation across the Axial zone. Structural observations through alpine thrusts coupled to geochronology (in situ K/Ar on phengites), Raman and chlorite-phengite thermo(baro)metry provide new key data to unravel the alpine evolution of the Pyrenees. According to preliminary ZFT results on granite massifs in the central part of Pyrenean Axial zone (near ECORS profile), exhumation ages potentially indicates a migration of exhumation towards the south. Exhumation ages of the northern massifs seems to have preserved the North Pyrenean Cretaceous rift evolution. Further south, the onset of exhumation is as old as Paleocene, which precedes the Eocene ages of the literature. The low burial estimated in the northern massifs may indicate a high thermal gradient

  14. Development of image capture system of fission tracks in plastic detectors; Desenvolvimento de sistema de captura de imagens de tracos nucleares em detectores plasticos

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Elder M. de; Melo, Vicente P. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil). Dept. de Protecao Radiologica Ambiental

    2001-07-01

    Plastic detectors are appropriate for detection and registration of alpha particles and fission products. The interaction of these particles with the detector damage its molecular structure, leading to a latent track (visible only under an electronic microscope) with diameter in the nanometer magnitude order. There are two etching methods: the conventional and the electrochemistry one. In the conventional etching the usual conditions is to attack with NaOH 6M, producing a track of average diameter of 3 {mu} m. In the electrochemistry etching the diameter is {approx} 150 {mu}m. The aim of this work is to show the functionality of the scanner for the acquisition of these images in conditions of electrochemistry etching. We employed the following attack solution: KOH/C{sub 2}H{sub 5}OH 15% p/v, pre-etching of 30 minutes, etching with tension of 1000 V, frequency of 100 Hz, during an hour and another stage of an hour, with frequency of 8 kHz. The images were acquired with optical resolution of 400 dpi and amplification of 300%, what allows printing in paper or counting and observation of the tracks in the screen. Results have shown that the replacement of the conventional system by a scanner computer device can be performed without loss of reliability of confidence in the tracks measurement and observation. (author)

  15. Determination of uranium content in dental porcelains by means of the fission track method and estimation of radiation dose to oral mucosa by radioactive elements

    International Nuclear Information System (INIS)

    Sairenji, Eiko; Moriwaki, Kazunari; Shimizu, Masami; Noguchi, Kunikazu; Anzai, Ikuro.

    1979-01-01

    Porcelain teeth, some of which contained uranium compounds for aesthetic purpose, have been widely used in dental clinics. Recently, the hazardous effects by uranium radiation were suggested. In the present study, the authors carried out the determination of uranium concentrations of four major brands of porcelain teeth marketed in Japan using the fission track method, and the absorbed doses of oral tissues were calculated by the authors' introduced formula for calculation of alpha radiation. Average uranium concentrations of the brands studied were determined 3.6 ppm (0.33 - 10 ppm, Japan), 18 ppm (0.69 - 81 ppm, Japan), 9.4 ppm (2.5 - 14 ppm, Japan) and 82 ppm (11 - 205 ppm, U.S.A.), respectively. The corresponding dose equivalents at the surface of oral mucosal membrane were 2.9 rem y -1 , 14 rem y -1 , 7.6 rem y -1 and 66 rem y -1 . (author)

  16. Determination of uranium content in dental porcelains by means of the fission track method and estimation of radiation dose to oral mucosa by radioactive elements

    International Nuclear Information System (INIS)

    Sairenji, E.; Moriwaki, K.; Shimizu, M.; Noguchi, K.

    1980-01-01

    Porcelain teeth, some of which contain uranium compounds for aesthetic purpose, have been widely used in dental clinics. Hazardous effects due to uranium radiation have been suggested in recent publications. In the present study uranium concentrations were determined in four major brands of porcelain teeth marketed in Japan using the fission track method, and the absorbed doses to oral tissued were calculated. Average uranium concentrations of the brands studied were determined to be 3.6 ppm (0.33-10 ppm, Japan), 18 ppm (0.69-81 ppm, Japan), 9.4 ppm (2.5-14 ppm, Japan) and 82 ppm (11-205 ppm, U.S.), respectively. The corresponding dose equivalents at the surface of oral mucosal membrane were 2.9 rem yr -1 . 14 rem yr -1 , 7.6 rem yr -1 and 66 rem yr -1 . (author)

  17. Comparisons of fission track age-determination and radioactivation analysis among radiation fields. Characteristic values for pneumatic tube, JRR-3M PN2

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Tatsuro [Kagoshima Univ. (Japan). Faculty of Education; Tomura, Kenji

    1996-01-01

    It is necessary for Fission track age determination and radioactivation analysis to define the energy spectrum of a reactor neutron as the basis for calculating the nuclear reaction rate. This study was made aiming to define the spectrum for PN2 pneumatic tube of No. 3 plant of Japan Atomic Energy Research Institute (JAERI). Characteristics such as conventional flux, cross reaction, neutron temperature and integral fast flux were examined for 3 facilities; JRR-2, JRR-4 and JRR-3M. And the neutron spectrum for each facility was estimated based on the assumptions; Maxwell distribution for thermal neutrons, 1/E for intermediate neutrons and Watt`s formula for fast neutrons. The present results showed that the spectrum for JRR-3M, PN2 was discontinuous in the range from the intermediate to the fast neutron, whereas those for other facilities were found considerably improved. (M.N.)

  18. A criticism of the paper entitled 'A practical method of estimating standard error of the age in the Fission Track Dating method' by Johnson, McGee and Naeser

    International Nuclear Information System (INIS)

    Green, P.F.

    1981-01-01

    It is stated that the common use of Poissonian errors to assign uncertainties in fission-track dating studies has led Johnson, McGee and Naeser (1979) to the mistaken assumption that such errors could be used to measure the spatial variation of track densities. The analysis proposed by JMN 79, employing this assumption, therefore leads to erroneous assessment of the error in an age determination. The basis for the statement is discussed. (U.K.)

  19. Calibration of a special neutron dosemeter based on solid-state track detectors and fission radiators in various neutron fields

    International Nuclear Information System (INIS)

    Doerschel, B.; Krusche, M.; Schuricht, V.

    1980-01-01

    The calibration of a personnel neutron dosemeter in different neutron fields is described. The badge-like dosemeter contains 5 detectors: polycarbonate foil (10 μm, Makrofol KG), 232 Th, natural uranium, natural uranium with boron, and natural uranium with cadmium. Detector sensitivity and calibration factors have been calculated and measured in radiation fields of 252 Cf fission neutrons, WWR-S reactor neutrons with and without Cd and Fe shielding, 3-MeV (d,t) generator neutrons, and 238 PuBe neutrons. Measurement range and achievable accuracy are discussed from the point of view of applying the dosemeter in routine and emergency uses

  20. The Carboniferous to Jurassic evolution of the pre-Alpine basement of Crete: Constraints from U-Pb and U-(Th)-Pb dating of orthogneiss, fission-track dating of zircon, structural and petrological data

    Czech Academy of Sciences Publication Activity Database

    Romano, S. S.; Brix, M. R.; Dörr, K.; Fiala, Jiří; Krenn, E.; Zulauf, G.

    2006-01-01

    Roč. 260, - (2006), s. 69-90 ISSN 0375-6440 Institutional research plan: CEZ:AV0Z30130516 Keywords : tectonic-evolution * Carboniferous * Jurassic * uranium-lead-dating * orthogneiss * fission-track-dating * zircon * structural-geology * petrology * metamorphism * high-temperature Subject RIV: DB - Geology ; Mineralogy

  1. Mesozoic cooling history of the “Bachu Uplift” in the Tarim Basin, China: Constraints from zircon fission-track thermochronology

    International Nuclear Information System (INIS)

    Chang, Jian; Brown, Roderick W.; Yuan, Wanming; Li, Wenzheng; Que, Yongquan; Qiu, Nansheng

    2014-01-01

    We applied zircon fission-track analysis to outcrop and borehole samples to study the Mesozoic cooling history of the Bachu Uplift, the Central Uplift of the Tarim Basin. Zircon fission-track (ZFT) ages of 182 Ma – 249 Ma are younger than the sample depositional ages indicating substantial post burial thermal annealing and can effectively reveal cooling events in the Bachu Uplift. The strong correlation between single grain ZFT age and U content indicates that most of the zircon grains represent ages that have been partially annealed and so the age is not directly indicative of the time of cooling. The youngest ZFT age populations with modal peak ages of 151 ± 8 Ma (Well HT1 samples), 126 ± 6 Ma (Well T1 samples) and 192 ± 10 Ma (Xiaohaizi Reservoir profile samples) from the decomposition of the ZFT single-grain ages represent the onset of cooling events in the Bachu Uplift, which were related to the collisions of the Qiangtang Terrane and Lhasa Block with the southern margin of the Eurasia continent, respectively. This study provides new insights into the tectonic and sedimentary evolution of the Tarim Basin and even Central Asia by constraining the higher temperature (c. 250–180 °C) part of the basin thermal history. - Highlights: • ZFT were firstly used to study Mesozoic cooling events of the Tarim Basin, China. • ZFT data revealed cooling events of 192 Ma, 151 Ma and 126 Ma. • Cooling events were related to the collisions in the Eurasia southern margin

  2. Reproducibility of old apatite (U-Th)/He ages: an example from East Greenland

    Science.gov (United States)

    Persano, C.; Swift, D. A.; Stuart, F. M.; Olive, V.

    2009-04-01

    In the last decade or so the apatite (U-Th)/He thermochronometer has proved increasingly useful as a tool for quantifying rates of denudation and hence the timing and mechanisms of landscape evolution. This has required advances in analytical procedures, a better understanding of the effects of alpha-recoil and parent element distribution on He diffusivity gradients, and the introduction of new software that enables users to combine (U-Th)/He data with apatite fission track information to better constrain thermal histories. However, several recent studies have shown that AHe ages in excess of 50-100 Ma are often older than expected based on the fission track ages of apatite from the same rock, implying that the apatite (U-Th)/He thermochronometer can be applied only to much ‘younger' landscapes. Here we present a statistically large number of replicate single-grain apatite (U-Th)/He age measurements from eighteen samples collected in the East Greenland fjord region in order to test the extent to which anomalously old AHe ages may reflect differences in crystal size and diffusion behaviour (as a result of radiation damage related to high [eU]). The samples constitute four topographic profiles, spanning elevations from sea-level to ~1100 m, collected in Devonian sandstone (1 profile) and Caledonian basement (3 profiles). Up to 20 transparent, euhedral crystals were analysed for each sample, resulting in a total of 214 (U-Th)/He determinations. Only one sample (He age: 31 ± 3 Ma; n = 6) reproduces within the 10% uncertainty that approaches the reproducibility (1 sigma) of the laboratory internal standard. Generally, reproducibility decreases with AHe age and samples with average ages older than ~ 50 Ma show particularly poor reproducibility, with standard deviations calculated over the arithmetic mean of the single-crystal corrected AHe ages of up to 40%. To explore the reasons for such poor reproducibility, we focus here on three samples from a single profile in

  3. Fission track thermochronology of Neogene plutons in the Principal Andean Cordillera of central Chile (33-35°S: Implications for tectonic evolution and porphyry Cu-Mo mineralization Termocronología mediante trazas de fision de plutones neógenos en la Cordillera Principal Andina de Chile central (33-35°S: Implicancias para la evolución tectónica y mineralización de pórfidos de Cu-Mo

    Directory of Open Access Journals (Sweden)

    Víctor Maksaev

    2009-07-01

    Full Text Available Apatite fission track data for Miocene plutons of the western slope of the Principal Andean Cordillera in central Chile (33-35°S define a distinct episode of enhanced crustal cooling through the temperature range of the apatite partial annealing zone (~125-60°C from about 6 to 3 Ma. This cooling episode is compatible with accelerated exhumation of the plutons at the time of Pliocene compressive tectonism, and mass wasting on the western slope of the Principal Andean Cordillera in central Chile. The timing coincides with the southward migration of the subducting Juan Fernández Ridge and the development of progressive subduction flattening northward of 33°S. It also corresponds to the time of active magmatic-hydrothermal processes and rapid unroofing of the world class Río Blanco-Los Bronces and El Teniente porphyry Cu-Mo deposits. Zircon fission track ages coincide with previous 40Ar/39Ar dates of the intrusions, and with some of the apatite fission track ages, being coherent with igneous-linked, rapid cooling following magmatic intrusion. The thermochronologic data are consistent with a maximum of about 8 km for Neogene exhumation of the plutons.Los datos de trazas de fision en apatita de plutones miocenos del flanco oeste de la Cordillera Principal de Chile central (33-35°S definen un episodio distintivo de enfriamiento acelerado a través del rango de temperatura de la zona de acortamiento parcial de trazas en apatita (~125-60°C entre los 6 a 3 Ma. Este episodio de enfriamiento es compatible con exhumación rápida de los plutones al tiempo del tectonismo compresivo plioceno y remociones en masa en el flanco oeste de la Cordillera Principal en Chile central. El período de tiempo coincide con la migración hacia el sur de la subducción de la Dorsal de Juan Fernández y con el desarrollo de un aplanamiento progresivo de la subducción hacia el norte de los 33°S. También corresponde al tiempo de actividad magmático-hidrotermal y r

  4. Method of reproducing images using fission fragments and/or alpha ray etch tracks from toned photographs

    International Nuclear Information System (INIS)

    Thackray, M.

    1976-01-01

    A method is described for producing a photographic image on a normally non-photo-receptive surface comprising the steps of 1) toning the photograph with substances which combine with or replace the silver grains so that the photograph emits either spontaneously or indirectly fission fragments or alpha particles in amounts related to the distribution of the silver grains in the photograph, 2) placing the toned photograph contiguous with the surface on which the image is to be reproduced, for sufficient time for the emissions from the photograph to reproduce the image as a radiation-damage image on the surface, the damage areas having a close positional relationship to the silver grains in the original photograph. (author)

  5. Fission-track ages of the Tokai Group and associate formations in the east coast areas of Ise Bay and their significance in geohistory

    International Nuclear Information System (INIS)

    Makinouchi, Takeshi; Danhara, Toru; Isoda, Kunitoshi.

    1983-01-01

    Fission-track ages of volcanic ash layers within the Tokai Group and associate formations in the east coast areas of Ise Bay are obtained by grain-by-grain method with which individual ages for the respective zircon grains are measured. They are as follows; 1) a volcanic ash layer in the Karayama Formation (tentative age: 1.9 +- 0.4 Ma). Among the zircon grains in this layer, essential ones occupy only 1 per cent, and the others are accidental. 2) Ohtani volcanic ash layer (4.3 +- 0.6 Ma). 3) Kosugaya volcanic ash layer (4.0 +- 0.5 Ma). 4) Kaminoma volcanic ash layer (5.3 +- 0.4 Ma). 5) A volcanic ash layer in the Toyoura Formation seems to be older than 10 Ma. 6) Zircon grains in the Kofu volcanic ash layer (Tokai Group) include two types of spontaneous namely track, clear and vague ones. The latter vague tracks are shorter and thiner, and seem to suffer thermal annealing. The ages obtained have clarified the following Points; a) The tentative age, 1.9 Ma, of the ''Karayama'' volcanic ash layer suggests the existence of unknown Plio-Pleistocene sediment in the Nagoya area. b) The sedimentary basin of Lake Tokai was formed in the latest Miocene, about 6.5 Ma. Generation of the basin coincides approximately with the stage of synchronous and abrupt change in sedimentation rate in sedimentary basins on the Pacific side of central and southern Japan. c) The Tokai Group in Chita (Tokoname Group) intercalates the Gilbert/Epoch 5 boundary in the paleomagnetic chronology in the middle horizon of the group. d) Average rate of sedimentation is about 1 m/10 4 yrs in the marginal areas of the basin, and 3-5 m/10 4 yrs in the central areas. (author)

  6. Application of the dating by fission tracks to determine thermicity of basins within petroleum potentialities: example of Sbaa and Ahnet-North basins located in Western Saharan platform, Algeria; Application de la datation par traces de fission a l'analyse de la thermicite de bassins a potentialites petrolieres: exemple de la cuvette de Sbaa et du bassin de l'Ahnet-Nord (plate-forme saharienne occidentale, Algerie)

    Energy Technology Data Exchange (ETDEWEB)

    Akkouche, M

    2007-05-15

    The interpretation of old fundamental research works and the results obtained by this study based on: the analysis of apatite fission tracks (AFT), the burial evolution curves and the sequential analysis of outcrop section, as well as the curves of signal of gamma ray (GR) analysis from drilling wells, allow to precise that the geodynamic evolution of the studied Algerian sedimentary basins (Ahnet and Sbaa) have been occurred principally in the Paleozoic era. The analysis of burial evolution curves shows that during the Paleozoic period, the sedimentation is controlled by the tectonic subsidence, particularly at the end of Carboniferous in the favor of Ougarta folding. The curves indicate an uplift from the Permian to middle Jurassic, expressed by an important erosion of sedimentary series and is considered as a response of thermal convection of the Saharan platform followed by thermal subsidence. This can be explained by the halt motion of rift extension caused by the opening of the Atlantic Ocean. To bring the sequential analysis out, it appears that Ahnet and Sbaa basins present contrasted stratigraphic recordings, so much in time than in space, indicated the different effects from subsidence and erosions according to their sectors. In thermal point of view, temperatures are still moderate in Sbaa depression and favorite the preservation of organic matter and might generate hydrocarbons until now. However, these conditions are not similar to ones in the case of Ahnet basin. In the North part of Ahnet basin (MRS-1, MSL-1), the ages are around 50 Ma, attested that sedimentary layers have been sustained a post-Hercynian thermal phase. This phase could be estimated probably more than 100 C. This is also produced during the regional extension of the Triassic-Jurassic rifting. This episode could also be responsible of disappearance (total?) of pre-existence fission tracks in the Devonian layers of the well MSR-1, which exhibits at the depth 505 m under the Hercynian

  7. Zircon fission track and U–Pb dating methods applied to São Paulo and Taubaté Basins located in the southeast Brazil

    International Nuclear Information System (INIS)

    Curvo, E.A.C.; Tello S, C.A.; Carter, A.; Dias, A.N.C.; Soares, C.J.; Nakasuga, W.M.; Resende, R.S.; Gomes, M.R.; Alencar, I.; Hadler, J.C.

    2013-01-01

    Zircon samples from the Cenozoic São Paulo and Taubaté Basins and Mantiqueira Mountain Range (southeast Brazil) were concomitantly dated by zircon Fission Track Method (FTM) and in situ U–Pb dating method. While FTM detrital-zircon data are ideally used to provide low-temperature information, U–Pb single detrital grain ages record the time of zircon formation in igneous or high grade metamorphic environments. This methodology may be used to study the possible sources of the basins sediments. The results suggest that the São Paulo Basin is composed of sediments from just one source, the Mantiqueira Mountain Range. On the other hand, the Taubaté Basin presents further sediment sources besides the Mantiqueira Mountain Range. - Highlights: ► Zircons from São Paulo and Taubaté Basins were dated by FTM and U–Pb. ► The zircon ages were compared with ages from the Mantiqueira Mountain Range (source). ► Results suggest the Mantiqueira is the source of sediments for the São Paulo Basin. ► The Taubaté Basin presents further sediment sources besides the Mantiqueira

  8. Reconciling Conflicting Geologic and Thermochronologic Interpretations Via Multiple Apatite Thermochronometers (AHe, AFT, and 4He/3He): 6 Ma Incision of the Westernmost Grand Canyon

    Science.gov (United States)

    Winn, C.; Karlstrom, K. E.; Shuster, D. L.; Kelley, S.; Fox, M.

    2017-12-01

    The application of low-temperature apatite thermochronology to the incision history of the Grand Canyon has led to conflicting hypotheses of either a 70 Ma ("old") or Hindu Fanglomerate was deposited across the present track of the Canyon; 2) The Separation Point basalt (19 Ma) is stranded between high relief tributaries and the main stem of the Colorado River; 3) Relief generation in tributaries and on plateaus adjacent to the Canyon took place after 17 Ma; and 4) The late Miocene-Pliocene Muddy Creek Formation shows that no far-traveled materials entered the Grand Wash Trough until after 6 Ma. Some interpretations of apatite thermochronology data conflict with these lines of evidence and indicate a much older ( 70 Ma) westernmost Grand Canyon. We reconcile this conflict by applying apatite (U-Th)/He ages (AHe), 4He/3He thermochronometry, and apatite fission track ages and lengths (AFT) to the same sample at a key location. Using HeFTy, t-T paths that predict these data show cooling from ˜100 °C to 40-60 °C at 70-50 Ma, long-term residence at 40-60 °C from 50-10 Ma, and cooling to surface temperatures after 10 Ma, indicating young incision. New AFT (5) and AHe (3) datasets are also presented here. When datasets are examined separately, AHe data show t-T paths that cool to surface temperatures during the Laramide, consistent with an "old" Canyon. When multiple methods are applied, t-T paths instead show young incision. This inconsistency demonstrates the age of the Grand Canyon controversy. Here we reconcile the difference in t-T paths by adjusting model parameters to account for uncertainty in the rate of radiation damage annealing in apatite during burial heating and the resulting variations in He retentivity. In this area, peak burial conditions during the Laramide were likely insufficient to fully anneal radiation damage that accumulated during prolonged near-surface residence prior to burial. We conclude that application of multiple thermochronometers from

  9. BIOMINERALOGICAL INVESTIGATION OF APATITE PIEZOELECTRICITY

    Directory of Open Access Journals (Sweden)

    M. Pawlikowski

    2016-01-01

    Full Text Available Investigation of apatite piezoelectricity was conducted in order to assess piezoelectric properties of bone. In the first stage, mineralogical analysis of different apatite crystals, regarding their purity and fitness for the experiments was performed. After the crystals had been chosen, 0.8 mm-thick plates were cut, perpendicular and parallel to the crystallographic Z axis. The plates were then polished and dusted with gold. Electrodes were attached to the opposite surfaces of the plates with conductive glue. So prepared plates were hooked up to the EEG machine used for measuring electrical activity in the brain. The plates were then gently tapped to observe and register currents generated in them. Acquired data was processed by subtracting from the resulting graphs those generated by a hand movement, without tapping the plate. Results indicate that apatite plates have weak piezoelectric properties. Observed phenomenon may be translated to bone apatite, which would explain, at least partially, piezoelectric properties of bone. Acquired results suggest that there is a relation between the mechanical workload of bones (bone apatite and theirelectrical properties. Considering the massive internal surface of bones, they may be treated as a kind of internal “antenna” reacting not only to mechanical stimuli, but to changes in electromagnetic field as well. Observed phenomena no doubt significantly influence the biological processes occurring in bones and the whole human body.

  10. Uranium-bearing francolites present in organic-rich limestones of NW Greece: a preliminary study using synchrotron radiation and fission track techniques

    DEFF Research Database (Denmark)

    Tzifas, I. T.; Glasmacher, U. A.; Misaelides, P.

    2017-01-01

    Synchrotron radiation techniques (μ-XRF and μ-XANES) were applied to the study of organic-rich phosphatized limestones of NW Greece (Epirus). The results revealed uranium accumulation in areas of the material containing, among others, carbonate apatite (francolite) and organic matter. The UL3-edg...

  11. Erosional history of the Appalachians as recordeed in detrital zircon fission-track ages and lithic detritus in Atlantic Coastal Plain sediments

    Science.gov (United States)

    Naeser, C.W.; Naeser, N.D.; Edwards, Lucy E.; Weems, Robert E.; Southworth, C. Scott; Newell, Wayne L.

    2016-01-01

    Comparison of fission-track (FT) ages of detrital zircons recovered from Atlantic Coastal Plain sediments to FT ages of zircons from bedrock in source terranes in the Appalachians provides a key to understanding the provenance of the sediments and, in turn, the erosional and depositional history of the Atlantic passive margin.In Appalachian source terranes, the oldest zircon fission-track (ZFT) ages from bedrock in the western Appalachians (defined for this paper as the Appalachian Plateau, Valley and Ridge, and far western Blue Ridge) are notably older than the oldest ages from bedrock in the eastern Appalachians (Piedmont and main part of the Blue Ridge). The age difference is seen both in ZFT sample ages and in individual zircon grain ages and reflects differences in the thermotectonic history of the rocks. In the east, ZFT data indicate that the rocks cooled from temperatures high enough to partially or totally reset ZFT ages during the Paleozoic and (or) Mesozoic. The majority of the rocks are interpreted to have cooled through the ZFT closure temperature (∼235 °C) at various times during the late Paleozoic Alleghanian orogeny. In contrast, most of the rocks sampled in the western Appalachians have never been heated to temperatures high enough to totally reset their ZFT ages. Reflecting their contrasting thermotectonic histories, nearly 80 percent of the sampled western rocks yield one or more zircon grains with very old FT ages, in excess of 800 Ma; zircon grains yielding FT ages this old have not been found in rocks in the Piedmont and main part of the Blue Ridge. The ZFT data suggest that the asymmetry of zircon ages of exposed bedrock in the eastern and western Appalachians was in evidence by no later than the Early Cretaceous and probably by the Late Triassic.Detrital zircon suites from sands collected in the Atlantic Coastal Plain provide a record of detritus eroded from source terranes in the Appalachians during the Mesozoic and Cenozoic. In Virginia

  12. Ternary fission

    International Nuclear Information System (INIS)

    Wagemans, C.

    1991-01-01

    Since its discovery in 1946, light (charged) particle accompanied fission (ternary fission) has been extensively studied, for spontaneous as well as for induced fission reactions. The reason for this interest was twofold: the ternary particles being emitted in space and time close to the scission point were expected to supply information on the scission point configuration and the ternary fission process was an important source of helium, tritium, and hydrogen production in nuclear reactors, for which data were requested by the nuclear industry. Significant experimental progress has been realized with the advent of high-resolution detectors, powerful multiparameter data acquisition systems, and intense neutron and photon beams. As far as theory is concerned, the trajectory calculations (in which scission point parameters are deduced from the experimental observations) have been very much improved. An attempt was made to explain ternary particle emission in terms of a Plateau-Rayleigh hydrodynamical instability of a relatively long cylindrical neck or cylindrical nucleus. New results have also been obtained on the so-called open-quotes trueclose quotes ternary fission (fission in three about-equal fragments). The spontaneous emission of charged particles has also clearly been demonstrated in recent years. This chapter discusses the main characteristics of ternary fission, theoretical models, light particle emission probabilities, the dependence of the emission probabilities on experimental variables, light particle energy distributions, light particle angular distributions, correlations between light particle accompanied fission observables, open-quotes trueclose quotes ternary fission, and spontaneous emission of heavy ions. 143 refs., 18 figs., 8 tabs

  13. Thorium-uranium fission radiography

    Science.gov (United States)

    Haines, E. L.; Weiss, J. R.; Burnett, D. S.; Woolum, D. S.

    1976-01-01

    Results are described for studies designed to develop routine methods for in-situ measurement of the abundance of Th and U on a microscale in heterogeneous samples, especially rocks, using the secondary high-energy neutron flux developed when the 650 MeV proton beam of an accelerator is stopped in a 42 x 42 cm diam Cu cylinder. Irradiations were performed at three different locations in a rabbit tube in the beam stop area, and thick metal foils of Bi, Th, and natural U as well as polished silicate glasses of known U and Th contents were used as targets and were placed in contact with mica which served as a fission track detector. In many cases both bare and Cd-covered detectors were exposed. The exposed mica samples were etched in 48% HF and the fission tracks counted by conventional transmitted light microscopy. Relative fission cross sections are examined, along with absolute Th track production rates, interaction tracks, and a comparison of measured and calculated fission rates. The practicality of fast neutron radiography revealed by experiments to data is discussed primarily for Th/U measurements, and mixtures of other fissionable nuclei are briefly considered.

  14. Singlet Fission

    Czech Academy of Sciences Publication Activity Database

    Smith, M. B.; Michl, Josef

    2010-01-01

    Roč. 110, č. 11 (2010), s. 6891-6936 ISSN 0009-2665 Grant - others:Department of Energy(US) DE- FG36 -08GO18017 Institutional research plan: CEZ:AV0Z40550506 Keywords : solar energy conversion * photovoltaics * singlet fission Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 33.033, year: 2010

  15. Ternary fission

    Indian Academy of Sciences (India)

    2015-08-05

    Aug 5, 2015 ... We present the ternary fission of 252Cf and 236U within a three-cluster model as well as in a level density approach. The competition between collinear and equatorial geometry is studied by calculating the ternary fragmentation potential as a function of the angle between the lines joining the stationary ...

  16. Ternary fission

    Indian Academy of Sciences (India)

    the energy minimization of all possible ternary breakups of a heavy radioactive nucleus. Further, within the TCM we have analysed the competition between different geometries as well as different positioning of the fragments. Also, an attempt was made to calculate the mass distribution of ternary fission process within the ...

  17. Fission fragment anisotropy of 235U measured with the fissionTPC

    Science.gov (United States)

    Hensle, David; Greife, Uwe; Niffte Collaboration

    2017-09-01

    The fissionTPC, built for the purpose of making neutron-induced fission cross section measurements with unprecedented precision, is a two-chamber MICROMEGAS time projection chamber that allows for three-dimensional tracking of charged particles. This three-dimensional tracking capability also provides a direct measurement of fission fragment angular distributions for neutron-induced fission. Fragment angular anisotropy is an important experimental observable for understanding the quantum mechanical state of the fissioning nucleus and a parameter required to determine detection efficiency for cross section measurements. Preliminary results for 235U fission fragment anisotropy as a function of neutron energies in the range 130 keV - 100 MeV will be presented.

  18. Mass dependence of positive pion-induced fission

    International Nuclear Information System (INIS)

    Khan, H.A.; Khan, N.A.; Peterson, R.J.

    1991-01-01

    Fission cross sections for a range of targets have been measured by solid-state track detectors following 80 and 100 MeV π + bombardment. Fission probabilities have been inferred by comparison to computed reaction cross sections. Fission probabilities for heavy targets agree with those for other probes of comparable energy and with statistical calculations. Probabilities for lighter targets are much above those previously observed or computed. Ternary fission cross sections and multiplicities of light fragments have also been determined

  19. Cumulative fission yield of Ce-148 produced by thermal-neutron fission of U-235

    International Nuclear Information System (INIS)

    Hasan, A.A.

    1984-12-01

    Cumulative fission yield of 148 cesium isotopes and some other fission products produced by thermal-neutron fission of 235 uranium is determined by Germanium/Lithium spectroscopic methods. The measuremets were done at Tsing-Hua open pool reactor using 3 to 4 mg of 93.15% enriched 235 uranium samples. Gamma rays are assigned to the responsible fission products by matching gamma rays energies and half lives. Fission rate is calculated by fission track method. Cumulative fission yields of 148 cesium, 90 krypton, 130 iodine, 144 lanthanum, 89 krypton, 136 xenon, 137 xenon and 140 cesium are calculated. This values are compared with previously predicted values and showed good agreement. 21 Ref

  20. Apatite glass-ceramics: a review

    Science.gov (United States)

    Duminis, Tomas; Shahid, Saroash; Hill, Robert Graham

    2016-12-01

    This article is a review of the published literature on apatite glass-ceramics (GCs). Topics covered include crystallization mechanisms of the various families of the apatite GCs and an update on research and development on apatite GCs for applications in orthopedics, dentistry, optoelectronics and nuclear waste management. Most apatite GCs crystallize through a homogenous nucleation and crystallization mechanism, which is aided by a prior liquid-liquid phase separation. Careful control of the base glass composition and heat-treatment conditions, which determine the nature and morphology of the crystal phases in the GC can produce GC materials with exceptional thermal, mechanical, optical and biological properties. The GCs reviewed for orthopedic applications exhibit suitable mechanical properties and can chemically bond to bone and stimulate its regeneration. The most commercially successful apatite GCs are those developed for dental veneering. These materials exhibit excellent translucency and clinical esthetics, and mimic the natural tooth mineral. Due to the ease of solid solution of the apatite lattice, rare earth doped apatite GCs are discussed for potential applications in optoelectronics and nuclear waste management. One of the drawbacks of the commercial apatite GCs used in orthopedics is the lack of resorbability, therefore the review provides a direction for future research in the field.

  1. Fission Fragment Angular Anisotropy in Neutron-Induced Fission of $^{235}$U Measured with a Time Projection Chamber

    OpenAIRE

    Geppert-Kleinrath, V.; Tovesson, F.; Barrett, J. S.; Bowden, N. S.; Bundgaard, J.; Casperson, R. J.; Cebra, D. A.; Classen, T.; Cunningham, M.; Duke, D. L.; Gearhart, J.; Greife, U.; Guardincerri, E.; Hagmann, C.; Heffner, M.

    2017-01-01

    Fission fragment angular distributions can provide insights into the quantum mechanical state of the transition nucleus at the saddle point and are therefore an important constraint on fission theory. Available anisotropy data is sparse, especially at neutron energies above 5 MeV. For the first time, a three-dimensional tracking detector is employed to study fragment emission angles and provide a direct measurement of angular anisotropy. The Neutron Induced Fission Fragment Tracking Experimen...

  2. Apatite-Melt Partitioning at 1 Bar: An Assessment of Apatite-Melt Exchange Equilibria Resulting from Non-Ideal Mixing of F and Cl in Apatite

    Science.gov (United States)

    McCubbin, F. M.; Ustunisik, G.; Vander Kaaden, K. E.

    2016-01-01

    The mineral apatite [Ca5(PO4)3(F,Cl,OH)] is present in a wide range of planetary materials. Due to the presence of volatiles within its crystal structure (X-site), many recent studies have attempted to use apatite to constrain the volatile contents of planetary magmas and mantle sources. In order to use the volatile contents of apatite to precisely determine the abundances of volatiles in coexisting silicate melt or fluids, thermodynamic models for the apatite solid solution and for the apatite components in multi-component silicate melts and fluids are required. Although some thermodynamic models for apatite have been developed, they are incomplete. Furthermore, no mixing model is available for all of the apatite components in silicate melts or fluids, especially for F and Cl components. Several experimental studies have investigated the apatite-melt and apatite-fluid partitioning behavior of F, Cl, and OH in terrestrial and planetary systems, which have determined that apatite-melt partitioning of volatiles are best described as exchange equilibria similar to Fe-Mg partitioning between olivine and silicate melt. However, McCubbin et al. recently reported that the exchange coefficients may vary in portions of apatite compositional space where F, Cl, and OH do not mix ideally in apatite. In particular, solution calorimetry data of apatite compositions along the F-Cl join exhibit substantial excess enthalpies of mixing. In the present study, we conducted apatite-melt partitioning experiments in evacuated, sealed silica-glass tubes at approximately 1 bar and 950-1050 degrees Centigrade on a synthetic Martian basalt composition equivalent to the basaltic shergottite Queen Alexandria Range (QUE) 94201. These experiments were conducted dry, at low pressure, to assess the effects of temperature and apatite composition on the partitioning behavior of F and Cl between apatite and basaltic melt along the F-Cl apatite binary join, where there is non-ideal mixing of F and Cl

  3. Fission fragment angular distributions and fission cross section validation

    International Nuclear Information System (INIS)

    Leong, Lou Sai

    2013-01-01

    The present knowledge of angular distributions of neutron-induced fission is limited to a maximal energy of 15 MeV, with large discrepancies around 14 MeV. Only 238 U and 232 Th have been investigated up to 100 MeV in a single experiment. The n-TOF Collaboration performed the fission cross section measurement of several actinides ( 232 Th, 235 U, 238 U, 234 U, 237 Np) at the n-TOF facility using an experimental set-up made of Parallel Plate Avalanche Counters (PPAC), extending the energy domain of the incident neutron above hundreds of MeV. The method based on the detection of the 2 fragments in coincidence allowed to clearly disentangle the fission reactions among other types of reactions occurring in the spallation domain. I will show the methods we used to reconstruct the full angular resolution by the tracking of fission fragments. Below 10 MeV our results are consistent with existing data. For example in the case of 232 Th, below 10 MeV the results show clearly the variation occurring at the first (1 MeV) and second (7 MeV) chance fission, corresponding to transition states of given J and K (total spin and its projection on the fission axis), and a much more accurate energy dependence at the 3. chance threshold (14 MeV) has been obtained. In the spallation domain, above 30 MeV we confirm the high anisotropy revealed in 232 Th by the single existing data set. I'll discuss the implications of this finding, related to the low anisotropy exhibited in proton-induced fission. I also explore the critical experiments which is valuable checks of nuclear data. The 237 Np neutron-induced fission cross section has recently been measured in a large energy range (from eV to GeV) at the n-TOF facility at CERN. When compared to previous measurements, the n-TOF fission cross section appears to be higher by 5-7 % beyond the fission threshold. To check the relevance of n-TOF data, we simulate a criticality experiment performed at Los Alamos with a 6 kg sphere of 237 Np. This

  4. Fission cross section measurements for minor actinides

    Energy Technology Data Exchange (ETDEWEB)

    Fursov, B. [IPPE, Obninsk (Russian Federation)

    1997-03-01

    The main task of this work is the measurement of fast neutron induced fission cross section for minor actinides of {sup 238}Pu, {sup 242m}Am, {sup 243,244,245,246,247,248}Cm. The task of the work is to increase the accuracy of data in MeV energy region. Basic experimental method, fissile samples, fission detectors and electronics, track detectors, alpha counting, neutron generation, fission rate measurement, corrections to the data and error analysis are presented in this paper. (author)

  5. Resolving the age of the first-order topography of southern Africa: new insight from joint (U-Th)/He and fission track dating of samples from deep boreholes

    Science.gov (United States)

    Beucher, R.; Brown, R. W.; Persano, C.; Stuart, F.; Gallagher, K.

    2011-12-01

    The topography of Africa is unusually high with respect to other continents and its origin remains strongly debated. Africa's topography is strongly bimodal as it is distributed between the high plateau areas in its central part (circa 1000 m), and significantly less elevated areas with higher relief around its borders. The geodynamical interpretation of this feature is not straightforward as the plateau is essentially surrounded by passive margins and oceanic ridges. However, abundant seismic studies have revealed a deep seismic anomaly beneath Africa and suggest that forces related to active upward flow within the mantle are dynamically sustaining its high elevation. If the large anomaly provides a mechanism explaining the south African plateau, a lot of questions remain on the timing of uplift. Geodynamic models allow Africa to go up or down but fail to put constrains on the age of the uplift. This is mainly because of a lack of tight constraints on the viscosity and density structure of the mantle, which lead to several models with uplift occurring either during Cretaceous or Miocene times. The question of the age of the plateau therefore remains unresolved. Thermochronology and techniques such as fission track and U-Th/He analyses provide tools to address this question by constraining the erosion history. In this study we take advantage of the availability of deep boreholes located all across south-Africa to sample truly vertical profiles through the plateau. The key advantage of this approach is that it enables constraints to be placed on the timing and amount of cooling resulting from relatively low amounts of erosion. A dozen boreholes from above and below the great escarpment have been sampled. We present fission track and U-Th/He results for three of them. The U-Th/He analyses are performed as single grain analyses with an average number of 15+ aliquots per sample for a total of 250+ single grain analyses in order to provide a high resolution chronology

  6. Energy released in fission

    International Nuclear Information System (INIS)

    James, M.F.

    1969-05-01

    The effective energy released in and following the fission of U-235, Pu-239 and Pu-241 by thermal neutrons, and of U-238 by fission spectrum neutrons, is discussed. The recommended values are: U-235 ... 192.9 ± 0.5 MeV/fission; U-238 ... 193.9 ± 0.8 MeV/fission; Pu-239 ... 198.5 ± 0.8 MeV/fission; Pu-241 ... 200.3 ± 0.8 MeV/fission. These values include all contributions except from antineutrinos and very long-lived fission products. The detailed contributions are discussed, and inconsistencies in the experimental data are pointed out. In Appendix A, the contribution to the total useful energy release in a reactor from reactions other than fission are discussed briefly, and in Appendix B there is a discussion of the variations in effective energy from fission with incident neutron energy. (author)

  7. Fission products collecting devices

    International Nuclear Information System (INIS)

    Matsumoto, Hiroshi

    1979-01-01

    Purpose: To enable fission products trap with no contamination to coolants and cover gas by the provision of a fission products trap above the upper part of a nuclear power plant. Constitution: Upon fuel failures in a reactor core, nuclear fission products leak into coolants and move along the flow of the coolants to the coolants above the reactor core. The fission products are collected in a trap container and guided along a pipeline into fission products detector. The fission products detector monitors the concentration of the fission products and opens the downstream valve of the detector when a predetermined concentration of the fission products is detected to introduce the fission products into a waste gas processing device and release them through the exhaust pipe. (Seki, T.)

  8. Anisotropic annealing of fission fragments in synthetic quartz

    CERN Document Server

    Sawamura, T; Narita, M

    1999-01-01

    A study on the thermal annealing behavior of fission fragments in synthetic quartz crystals was performed for application of synthetic quartz to track detectors under high temperature circumstances: x-, y-, and z-cut quartz plates were exposed to fission fragments from sup 2 sup 5 sup 2 Cf and were annealed up to 750 deg. C. It was found that track retention depended on the crystallographic structure: the annealing temperature, where the number of etched tracks was sharply reduced, was 550 deg. C for the x- and y-cut plates and 750 deg. C for z-cut plates. Track sizes decrease and disperse with reductions in the track retention.

  9. Efficiency of SSNTD Spark Counters with fission fragment angular distribution

    International Nuclear Information System (INIS)

    Lopes, R.T.; Rogers, J.D.

    1982-01-01

    Fission fragments from a 252 Cf source were detected in 10 μm thick Makrofol KG plastic. Measurements were done of observed track densities less than 100 tracks/cm 2 . The efficiency of the counter was determined as a function of the actual track density for each angle of incidence and correction factors analysed of the resulting counting losses. (author) [pt

  10. Low Temperature Paleogene Thermal Evolution of the British Mountains using Apatite U-Th/He Dating, Northern Yukon, Canada

    Science.gov (United States)

    Pickering, J. E.; Guest, B.; Schneider, D. A.; Lane, L.

    2014-12-01

    The age and rate of exhumation of the British Mountains is tied to the timing of deformation in the Beaufort Sea, an active site for hydrocarbon exploration. This region contains a large portion of North America's oil and gas reserves. The British Mountains, the eastern extent of the Brooks Range in Alaska, include Paleogene structures that are the onshore portion of the Beaufort fold belt. In the Beaufort Sea, deformation is dominated by thin-skinned folding and thrusting of Paleocene to Oligocene sediments that is sourced from the British Mountains. Onshore, Paleogene deformation overprints multiple older structural events. The low temperature time history of the onshore Paleogene structures will be determined through U-Th/He dating of apatites (AHe). The results will contribute to better understanding of the timing of the maturation and migration of hydrocarbons in the Beaufort Sea. Previous work on the thermal history of northern Yukon and the North Slope of Alaska provides a regional framework for the region's low temperature-time history. These regional studies of the northern Yukon and Alaska yielded Paleocene to Eocene (60Ma - 40Ma) apatite fission track (AFT) cooling ages that progressively young to the north, consistent with geological evidence for northward propagating deformation. The British Mountains consist of Neoproterozoic to early Paleozoic marine sediments that are intruded by scattered Devonian plutons; both rock types will be included in the study. This study aims to improve the understanding of the Paleogene tectonic activity of the British Mountains and the deformation history of the Beaufort fold belt. The two data sets, existing AFT and new AHe results, will be both be included in the interpretation of the study area. We will present AHe data to better constrain the onshore exhumation and deformation rates at low temperatures (~60-90°C). A sampled transect through the British mountains, along the Firth River valley will provide good

  11. Modeling the Fission Fragment Detection Efficiency of the NIFFTE fissionTPC

    Science.gov (United States)

    Bowden, Nathaniel; Niffte Collaboration

    2017-09-01

    The goal of the Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) is to measure neutron-induced fission cross section ratios with unprecedented precision. The NIFFTE Collaboration has designed and built a Time Projection Chamber, the fissionTPC, for this purpose. The detector enables charged particle tracking with full three-dimensional charge cloud reconstruction, allowing for the characterization of fission fragments originating from a thin central target. Quantifying the fission fragment detection efficiency is a central element of these cross section ratio measurements. Here we describe how the wealth of data captured for every fission event allows us to build and validate a detailed Monte Carlo efficiency model. Effects such as anisotropy, fission fragment energy degradation, and target thickness, composition, and roughness must all be taken into account. LLNL-ABS-733618. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  12. Comparison of two carbonated apatite ceramics in vivo

    NARCIS (Netherlands)

    Habibovic, Pamela; Juhl, Maria V.; Clyens, Stuart; Martinetti, Roberta; Dolcini, Laura; Theilgaard, Naseem; van Blitterswijk, Clemens

    2010-01-01

    Carbonated apatite ceramics, with a composition similar to that of bone mineral, are potentially interesting synthetic bone graft substitutes. In the present study, two porous carbonated apatite ceramics were developed, characterized and tested for their bone repair capacity and osteoinductive

  13. Solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Medeiros, J.A.; Carvalho, M.L.C.P. de

    1992-12-01

    Solid state nuclear track detectors (SSNTD) are dielectric materials, crystalline or vitreous, which registers tracks of charged nuclear particles, like alpha particles or fission fragments. Chemical etching of the detectors origin tracks that are visible at the optical microscope: track etching rate is higher along the latent track, where damage due to the charged particle increase the chemical potential, and etching rate giving rise to holes, the etched tracks. Fundamental principles are presented as well as some ideas of main applications. (author)

  14. Fission Research at IRMM

    Directory of Open Access Journals (Sweden)

    Al-Adili A.

    2010-03-01

    Full Text Available Fission Research at JRC-IRMM has a longstanding tradition. The present paper is discussing recent investigations of fission fragment properties of 238 U(n,f, 234 U(n,f, prompt neutron emission in fission of 252 Cf(SF as well as the prompt fission neutron spectrum of 235 U(n,f and is presenting the most important results.

  15. A multidisciplinary analysis to constrain exhumation and recent erosion history of the Tethyan Himalaya, based on apatite (U-Th-Sm)/He and cosmogenic nuclides dates from Central Nepal (Takkhola graben and the Mustang granite)

    Science.gov (United States)

    Rosenkranz, Ruben; Sahragard Sohi, Mohammad; Spiegel, Cornelia

    2015-04-01

    rates through time for the region north to the South Tibetan Detachment. It is our expectation to link the results to the tectonic behavior of the South Tibetan Detachment or to the newly recognized Western Nepal Fault System. Corroborating our results with other ages and diverse methods will provide a robust constraint on the exhumation and erosion history of the Tethyan Himalaya, as well as insights on the U-Th/He dating technique. References Adhikari, B.R. and Wagreich, M., 2011. Provenance evolution of collapse graben fill in the Himalaya-The Miocene to Quaternary Thakkhola-Mustang graben (Nepal). Sedimentary Geology, 233(1), pp.1-14. Blythe, A.E., Burbank, D.W., Carter, A., Schmidt, K., Putkonen, J., 2007. Plio-Quaternary exhumation history of the central Nepalese Himalaya: 1. Apatite and zircon fission track and apatite [U-Th]/He analyses. Tectonics, 26(3). Crouzet, C. et al., 2007. Temperature and age constraints on the metamorphism of the Tethyan Himalaya in Central Nepal: A multidisciplinary approach. Journal of Asian Earth Sciences, 30(1), pp.113-130. Garzione, C.N, DeCelles, P.G., Hokinson, D.G., Ojha, T.P., Upreti, B.N., 2003. East-west extension and Miocene environmental change in the southern Tibetan plateau: Thakkhola graben, central Nepal. Geological Society of America Bulletin, 115(1), pp.3-20. Colchen, M., 1999. The Takkhola-Mustang graben in Nepal and the latee Cenozoic extension in the Higher Himalayas. Journal of Asian Earth Sciences, 17, pp. 683-702.

  16. Fission- and alpha-track study of biogeochemistry of plutonium and uranium in carbonates of Bikini and Enewetak atolls. Progress report, January 1, 1976--December 31, 1976

    International Nuclear Information System (INIS)

    Levy, Y.; Miller, D.S.; Friedman, G.M.

    1976-09-01

    Alpha emitters have been detected with a resolution of a few tens of micrometers using a solid state track detector (cellulose nitrate) to map the activity in a coral sample from Bikini. Calibration methods used include: a Pu source of 0.15 μCi in conjunction with polycarbonate and CaCO 3 absorbers of different thicknesses (2 to 30 micrometers), and a powdered coral sample which had been analyzed previously for alpha emitters by chemical methods in conjunction with an alpha spectrometer. 0.04 mm 3 can be measured routinely; smaller concentrations can be determined but with a lower resolution. CaCO 3 of the coral Favites virens from Bikini lagoon was analyzed by placing the detector directly on the sample for thirty days. Sections and thin sections cut perpendicular to one another, but parallel to the direction of coral growth, give very different concentrations and distributions of alpha emitters. Maximum concentrations of 800 pCi/g were measured in a volume of 0.004 mm 3 in void-filling cement separated from the coral and in an area in which coral skeleton and cement could not be distinguished. Areas of high alpha emitter concentrations coincide with areas of coral growth interruption where non coral material exists that is composed of a mixture of encrusting bryozoan like carbonate material and skeletal debris

  17. Fission- and alpha-track study of biogeochemistry of plutonium and uranium in carbonates of Bikini and Enewetak atolls. Summary report, 1 July 1974--31 August 1977

    Energy Technology Data Exchange (ETDEWEB)

    Levy, Y.; Miller, D. S.; Friedman, G. M.

    1977-09-01

    Alpha emitters of pCi/g amounts have been detected with a resolution of a few micrometers using a solid state track detector (cellulose nitrate) to map the activity in a coral sample from Bikini. Calibration methods used include: a Pu source of 0.15 ..mu..Ci in conjunction with polycarbonate and CaCO/sub 3/ absorbers of different thicknesses (2 to 30 micrometers), and a powdered coral sample which had been analyzed previously for alpha emitters by chemical methods in conjunction with an alpha spectrometer. 0.04 mm/sup 3/ can be measured routinely; lower concentrations can be determined but with less resolution. The alpha emitter concentration in CaCO/sub 3/ of the coral Favites virens from Bikini lagoon was analyzed by placing the detector directly on the slab sample for thirty days. Analyses of sections and thin sections of this coral slab cut perpendicular to one another, but parallel to the direction of coral growth, give very different concentrations and distributions of alpha emitters.

  18. IN SITU LEAD IMMOBILIZATION BY APATITE

    Science.gov (United States)

    Lead contamination is of environmental concern due to its effect on human health. The purpose of this study was to develop a technology to immobilize Pb in situ in contaminated soils and wastes using apatite. Hydroxyapatite [Ca10(PO4)6(O...

  19. Study of damage and helium diffusion in fluoro-apatites; Etude de l'endommagement et de la diffusion de l'helium dans des fluoroapatites

    Energy Technology Data Exchange (ETDEWEB)

    Miro, S

    2004-12-15

    This work lies within the scope of the study of the radionuclides containment matrices. The choice of the fluoro-apatites as potential matrices of containment was suggested by the notable properties of these latter (thermal and chemical stability even under radioactive radiation). By irradiations with heavy ions and a helium implantation we simulated the effects related to the alpha radioactivity and to the spontaneous nuclear fission of the radionuclides. Thanks to the study of Durango fluoro-apatite single crystals and fluoro-apatite sintered ceramics, we evidenced that the damage fraction as well as the unit cell deformations increase with the electronic energy loss and with the substitution. These effects are followed at high fluences by a phenomenon of re-crystallization. The study of the helium diffusion points out that the thermal diffusion process improves with the substitution and strongly increases with heavy ions irradiation. (author)

  20. Intermediate energy nuclear fission

    International Nuclear Information System (INIS)

    Hylten, G.

    1982-01-01

    Nuclear fission has been investigated with the double-kinetic-energy method using silicon surface barrier detectors. Fragment energy correlation measurements have been made for U, Th and Bi with bremsstrahlung of 600 MeV maximum energy. Distributions of kinetic energy as a function of fragment mass are presented. The results are compared with earlier photofission data and in the case of bismuth, with calculations based on the liquid drop model. The binary fission process in U, Yb, Tb, Ce, La, Sb, Ag and Y induced by 600 MeV protons has been investigated yielding fission cross sections, fragment kinetic energies, angular correlations and mass distributions. Fission-spallation competition calculations are used to deduce values of macroscopic fission barrier heights and nuclear level density parameter values at deformations corresponding to the saddle point shapes. We find macroscopic fission barriers lower than those predicted by macroscopic theories. No indication is found of the Businaro Gallone limit expected to occur somewhere in the mass range A = 100 to A = 140. For Ce and La asymmetric mass distributions similar to those in the actinide region are found. A method is described for the analysis of angular correlations between complementary fission products. The description is mainly concerned with fission induced by medium-energy protons but is applicable also to other projectiles and energies. It is shown that the momentum and excitation energy distributions of cascade residuals leading to fission can be extracted. (Author)

  1. Lunar apatite with terrestrial volatile abundances.

    Science.gov (United States)

    Boyce, Jeremy W; Liu, Yang; Rossman, George R; Guan, Yunbin; Eiler, John M; Stolper, Edward M; Taylor, Lawrence A

    2010-07-22

    The Moon is thought to be depleted relative to the Earth in volatile elements such as H, Cl and the alkalis. Nevertheless, evidence for lunar explosive volcanism has been used to infer that some lunar magmas exsolved a CO-rich and CO(2)-rich vapour phase before or during eruption. Although there is also evidence for other volatile species on glass spherules, until recently there had been no unambiguous reports of indigenous H in lunar rocks. Here we report quantitative ion microprobe measurements of late-stage apatite from lunar basalt 14053 that document concentrations of H, Cl and S that are indistinguishable from apatites in common terrestrial igneous rocks. These volatile contents could reflect post-magmatic metamorphic volatile addition or growth from a late-stage, interstitial, sulphide-saturated melt that contained approximately 1,600 parts per million H(2)O and approximately 3,500 parts per million Cl. Both metamorphic and igneous models of apatite formation suggest a volatile inventory for at least some lunar materials that is similar to comparable terrestrial materials. One possible implication is that portions of the lunar mantle or crust are more volatile-rich than previously thought.

  2. Sulfur concentration and isotopic variation in apatites from granitic to granodioritic plutons of a Cretaceous Cordilleran Batholith

    Science.gov (United States)

    Economos, R. C.

    2012-12-01

    Apatite is a common igneous accessory mineral with a high saturation temperature which can therefore crystallize over a significant portion of magmatic compositional space. Sulfur presents an opportunity to identify zoning in apatites. Unlike other trace elements, sulfur is relatively immobile in the apatite crystal structure and can be present in typical concentrations up to 1500 - 2000 ppm (or 0.5 to 1 wt% SO3). Sulfur concentration zoning in igneous apatites from ore producing magmatic systems has been identified (Streck and Dilles, 1998), but the interpretation of the cause of this zoning remains an open question. δ34S isotopic ratios of whole apatites have been used to track isotopic evolution associated with changes in magma fO2 and eruptive degassing (Rye, 2005). The presented work combines sulfur concentration mapping in zoned apatite crystals with in-situ SIMS 34S and 32S isotope measurements. Apatites were extracted from granite to granodiorite samples from the Cadiz Valley Batholith in the central Mojave Desert. This batholith is related to the pulse of Cretaceous Cordilleran magmatism that generated large batholiths in the Sierra Nevada and the Penninsular Ranges. The Mojave segment of the Cretaceous arc is unique in their construction into a full thickness of continental crust which exerted a strong influence on magmatic compositions. Apatite grains were mounted parallel to C axes, ground until grains were approximately bisected, and analyzed by Electron Microprobe at UCLA, for CaO, P2O5, SO3 and SiO2. Grains were surveyed and those yielding anomalous SO3 contents were investigated by micron-scale concentration mapping. Typical SO3 concentrations of apatites from all samples were ~0.2 wt%, while 8 to 10% of apatite grains from two samples contained cores with concentrations ranging up to 0.5 wt%. The sulfur zoning in these samples is oscillatory, in some grains representing 5 to 6 repetitions of high and low concentrations. Based on these textures

  3. Fission rate sensitivities and fission fragment ranges for uranium and thorium-bearing materials irradiated with 252 Cf neutron source

    International Nuclear Information System (INIS)

    Moharram, B.M.

    2000-01-01

    The induced fission reactions of 235 U (n, f), 238 U (n,f) and 232 Th (n, f) based on the activation of natural uranium and thorium in samples with 252 Cf, neutron source, have been evaluated. The obtained results are the average of three samples from each test material (SRM 2710 Montana soil and Zirconia). The prepared samples have been configured in the so-called c ompensated - beam geometry i n which both gamma spectrometry jointly with solid state nuclear track detector techniques, revealed the fission rate sensitivity of 4.64 x 10 7 fission per gram per second per neutron (F.h 1 . S 1 .n 1 ), for zirconia as obtained by gamma activity arising from 134 I fission product (as a good monitor which is produced only from fissions), and the related value for SRM 2710 soil is 5.22 x 10 8 (F.g 1 S 1 .n 1 ). while the obtained values of the mean fission fragment ranges in SRM 2710 and zirconia as estimated from the fission track densities (by CR-39) and fission rates (by gamma spectrometry) are 3.97 x 10 3 g. cm 2 respectively which reveal good agreement with experiments and calculations done hitherto

  4. Beta transmutations in apatites with ferric iron as an electron acceptor - implication for nuclear waste form development.

    Science.gov (United States)

    Yao, Ge; Zhang, Zelong; Wang, Jianwei

    2017-09-27

    Apatite-structured materials have been considered for the immobilization of a number of fission products from reprocessing nuclear fuel because of their chemical durability as well as compositional and structural flexibility. It is hypothesized that the effect of beta decay on the stability can be mitigated by introducing an appropriate electron acceptor at the neighboring sites in the structure. The decay series 137 Cs → 137 Ba and 90 Sr → 90 Y → 90 Zr were investigated using a spin-polarized DFT approach to test the hypothesis. Apatites with compositions of Ca 10 (PO 4 ) 6 F 2 and Ca 4 Y 6 (SiO 4 ) 6 F 2 were selected as model systems for the incorporation of radionuclides Cs and Sr, respectively. Ferric iron was introduced in the structure as an electron acceptor. Electron density of states, crystal and defect structures, and energies before and after beta decay were calculated. The calculated electron density of states suggests that the extra electron is localized at the ferric iron, which changes its oxidation state and becomes ferrous iron. The crystal and defect structures were analyzed based on the volume, lattice parameters, radial distribution functions, metal cation to coordinating oxygen distances, and the metaprism twist angle of the apatite crystal structure. The results show that there are minor changes in the crystal and defect structures of CsFeCa 8 (PO 4 ) 6 F 2 with Cs + and Fe 3+ substitutions undergoing the Cs → Ba transmutation, and of Ca 3 SrY 4 Fe 2 (SiO 4 ) 6 F 2 with Sr 2+ and Fe 3+ substitutions undergoing the Sr → Y → Zr transmutations. The last decay change, from Y 3+ → Zr 4+ , causes relatively larger changes in the local defect structure around Zr involving the coordination environment but the change is not significant to the crystal structure. The results on calculated cohesive energy suggest that the transmutations Cs + → Ba 2+ and Sr 2+ → Y 3+ → Zr 4+ in both apatite compositions are energetically favorable

  5. Fission Spectrum Related Uncertainties

    Energy Technology Data Exchange (ETDEWEB)

    G. Aliberti; I. Kodeli; G. Palmiotti; M. Salvatores

    2007-10-01

    The paper presents a preliminary uncertainty analysis related to potential uncertainties on the fission spectrum data. Consistent results are shown for a reference fast reactor design configuration and for experimental thermal configurations. However the results obtained indicate the need for further analysis, in particular in terms of fission spectrum uncertainty data assessment.

  6. The nuclear fission

    International Nuclear Information System (INIS)

    Fiorentino, J.

    1983-01-01

    The nuclear fission process considering initially the formation of compound nucleus and finishing with radioactive decay of fission products is studied. The process is divided in three parts which consist of the events associated to the nucleus of intermediate transitional state, the scission configuration, and the phenomenum of post scission. (M.C.K.) [pt

  7. The nuclear fission process

    International Nuclear Information System (INIS)

    Wagemans, C.

    1991-01-01

    Fifty years after its discovery, the nuclear fission phenomenon is of recurring interest. When its fundamental physics aspects are considered, fission is viewed in a very positive way, which is reflected in the great interest generated by the meetings and large conferences organized for the 50th anniversary of its discovery. From a purely scientific and practical point of view, a new book devoted to the (low energy) nuclear fission phenomenon was highly desirable considering the tremendous amount of new results obtained since the publication of the book Nuclear Fission by Vandenbosch and Huizenga in 1973 (Academic Press). These new results could be obtained thanks to the growth of technology, which enabled the construction of powerful new neutron sources, particle and heavy ion accelerators, and very performant data-acquisition and computer systems. The re-invention of the ionization chamber, the development of large fission fragment spectrometers and sophisticated multiparameter devices, and the production of exotic isotopes also contributed significantly to an improved understanding of nuclear fission. This book is written at a level to introduce graduate students to the exciting subject of nuclear fission. The very complete list of references following each chapter also makes the book very useful for scientists, especially nuclear physicists. The book has 12 chapters covering the fission barrier and the various processes leading to fission as well as the characteristics of the various fission reaction products. In order to guarantee adequate treatment of the very specialized research fields covered, several distinguished scientists actively involved in some of these fields were invited to contribute their expertise as authors or co-authors of the different chapters

  8. RBS and RNRA studies on sorption of europium by apatite

    Energy Technology Data Exchange (ETDEWEB)

    Ohnuki, Toshihiko; Kozai, Naofumi; Isobe, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Murakami, Takashi; Yamamoto, Shunya; Aoki, Yasushi; Naramoto, Hiroshi

    1997-03-01

    The sorption mechanism of europium, alternative of trivalent TRU has been studied based on the depth profiles of elements obtained by Rutherford Backscattering Spectroscopy (RBS) and Resonant Nuclear Reaction Analysis (RNRA). The positive peak for Eu and the negative peak for Ca were observed in the subtracted RBS spectra of the apatites on which Eu was sorbed from that of the fresh apatite. This indicates that Eu was sorbed on apatite, while a fraction of Ca was released from apatite. The peak height for Eu in the RBS spectrum of the apatite obtained at 75degC was higher than that of the apatite at 40degC. The depth profile of hydrogen of the apatite on which Eu was sorbed was similar to that of the fresh apatite. The concentration of Eu in the solution decreased with increasing temperature. On the contrary, the concentration of Ca increased with increasing temperature. Thus, it is concluded that a fraction of Eu is exchanged for Ca in the structure of apatite. (author)

  9. A Time Projection Chamber for High Accuracy and Precision Fission Cross-Section Measurements

    Energy Technology Data Exchange (ETDEWEB)

    T. Hill; K. Jewell; M. Heffner; D. Carter; M. Cunningham; V. Riot; J. Ruz; S. Sangiorgio; B. Seilhan; L. Snyder; D. M. Asner; S. Stave; G. Tatishvili; L. Wood; R. G. Baker; J. L. Klay; R. Kudo; S. Barrett; J. King; M. Leonard; W. Loveland; L. Yao; C. Brune; S. Grimes; N. Kornilov; T. N. Massey; J. Bundgaard; D. L. Duke; U. Greife; U. Hager; E. Burgett; J. Deaven; V. Kleinrath; C. McGrath; B. Wendt; N. Hertel; D. Isenhower; N. Pickle; H. Qu; S. Sharma; R. T. Thornton; D. Tovwell; R. S. Towell; S.

    2014-09-01

    The fission Time Projection Chamber (fissionTPC) is a compact (15 cm diameter) two-chamber MICROMEGAS TPC designed to make precision cross-section measurements of neutron-induced fission. The actinide targets are placed on the central cathode and irradiated with a neutron beam that passes axially through the TPC inducing fission in the target. The 4p acceptance for fission fragments and complete charged particle track reconstruction are powerful features of the fissionTPC which will be used to measure fission cross-sections and examine the associated systematic errors. This paper provides a detailed description of the design requirements, the design solutions, and the initial performance of the fissionTPC.

  10. Fission 2009 4. International Workshop on Nuclear Fission and Fission Product Spectroscopy - Compilation of slides

    International Nuclear Information System (INIS)

    2009-01-01

    This conference is dedicated to the last achievements in experimental and theoretical aspects of the nuclear fission process. The topics include: mass, charge and energy distribution, dynamical aspect of the fission process, nuclear data evaluation, quasi-fission and fission lifetime in super heavy elements, fission fragment spectroscopy, cross-section and fission barrier, and neutron and gamma emission. This document gathers the program of the conference and the slides of the presentations

  11. Measurements of the effective range of fission fragments in UO2 and the disintegration constant for spontaneous fission of 238U

    International Nuclear Information System (INIS)

    Spaggiari, E.R.V.

    1978-01-01

    The results of measuments of the disintegration constant for spontaneous fission in 238 U are presented, with a discussion on the method used for the detection of fission tracks in muscovite mica. Samples of muscovite mica sandwiched between two natural uranium dioxide cylinders were irradiated with fragments of spontaneous fission and the etched tracks counted with projetion optical microscope. The effective thickness of the UO 2 layer which contributed to the observed tracks was measured through irradiation of mica samples, in contact with the UO 2 cylinder with 14,0 MeV neutrons from a (d,t) reaction. (Author) [pt

  12. Fission/milligram of 235U in BIG-10 Tests A, C, E, and B

    International Nuclear Information System (INIS)

    Gilliam, D.M.; Grundl, J.A.; Hansen, G.E.

    1976-01-01

    The entire series of dosimetry foil tests at BIG-10 (including the preliminary Test A, five fission foil set irradiations--Tests C, five non-fission foil set irradiations--Tests E, and five track-etch detector irradiations--Tests B) were monitored continuously by the NBS double fission chamber PP5 in the central test cavity. The accuracy of the absolute fission counting data (fissions/milligram of 235 U) is estimated to be 1.4% for Tests A, C, and E and 1.5% for Test B. Deposit mass assay uncertainties remain the dominant error

  13. DEATH-STAR: Silicon and Photovoltaic Fission Fragment Detector Arrays for Light-Ion Induced Fission Correlation Studies

    Science.gov (United States)

    Koglin, J. D.; Burke, J. T.; Fisher, S. E.; Jovanovic, I.

    2017-05-01

    The Direct Excitation Angular Tracking pHotovoltaic-Silicon Telescope ARray (DEATH-STAR) combines a series of 12 silicon detectors in a ΔE - E configuration for charged particle identification with a large-area array of 56 photovoltaic (solar) cells for detection of fission fragments. The combination of many scattering angles and fission fragment detectors allows for an angular-resolved tool to study reaction cross sections using the surrogate method, anisotropic fission distributions, and angular momentum transfers through stripping, transfer, inelastic scattering, and other direct nuclear reactions. The unique photovoltaic detectors efficiently detect fission fragments while being insensitive to light ions and have a timing resolution of 15.63±0.37 ns. Alpha particles are detected with a resolution of 35.5 keV 1σ at 7.9 MeV. Measured fission fragment angular distributions are also presented.

  14. Determination of radiological age of volcanic ashes and tuffs from neogenic and Quaternary deposits Ponto-Caspian region and Bolshaya Kuril ridge by a track method

    International Nuclear Information System (INIS)

    Ushko, K.A.; Kashkarov, L.L.; Koshkin, V.L.

    1987-01-01

    Results of determining radiological age of a number of volcanogenic rocks in two main regions, Ponto-Caspian region and Bolshaya Kuril ridge, by a specially developed track method of dating volcanic ashes and tuffs are presented. The above method is based on registering uranium fission fragments by accessory apatite which serves as a detector. The age values of the above rocks agree well with the data of stratigrapho-paleonthological investigations and range from 0.7+-0.2 m years to 3.0+-0.4 m years for different ash samples; 0.51+-0.04 m years for ash tuffs and from 3.6+-1.0 to 11.2+-1.9 m years for tuffs

  15. Rare earth elements materials production from apatite ores

    International Nuclear Information System (INIS)

    Anufrieva, A V; Buynovskiy, A S; Makaseev, Y N; Mazov, I N; Nefedov, R A; Sachkov, V I; Valkov, A V; Andrienko, O S; Stepanova, O B

    2016-01-01

    The paper deals with the study of processing apatite ores with nitric acid and extraction of the rare earth elements. The rare earth elements can be successfully separated and recovered by extraction from the nitrate- phosphate solution, being an tributyl phosphate as extraction agent. The developed scheme of the processing apatite concentrate provides obtaining rare earth concentrates with high qualitative characteristics. (paper)

  16. Fission in a Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Younes, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-10-26

    A three-year theory project was undertaken to study the fission process in extreme astrophysical environments, such as the crust of neutron stars. In the first part of the project, the effect of electron screening on the fission process was explored using a microscopic approach. For the first time, these calculations were carried out to the breaking point of the nucleus. In the second part of the project, the population of the fissioning nucleus was calculated within the same microscopic framework. These types of calculations are extremely computer-intensive and have seldom been applied to heavy deformed nuclei, such as fissioning actinides. The results, tools and methodologies produced in this work will be of interest to both the basic-science and nuclear-data communities.

  17. IN SITU LEAD STABILIZATION USING NATURAL AND SYNTHETIC APATITE

    Directory of Open Access Journals (Sweden)

    T. Kaluđerović Radoičić

    2008-11-01

    Full Text Available In this work, mineral apatite was investigated for the remediation of lead contamination. Two different apatite minerals were used: synthetic apatite, Ca10(PO46(OH2 (hereafter denoted as HAP and natural apatite from Lisina, near Bosilegrad, Serbia (hereafter denoted as LA. Phosphate ore from Lisina deposit consists of 43.3 % apatite in the form of fluorapatite, Ca10(PO46(F2. Sorption properties of HAP and LA were investigated. The results show that both of these minerals are effective in lead removal from the water solution. Sorption capacity of HAP obtained in this experiment is 0.216 mmol Pb/g HAP, while the value for LA is 0.162 mmol Pb/g LA. Modeling of these systems was conducted using Visual Minteq computer program. The values obtained from the computer simulation were compared to experimental values.

  18. Alkaline glass as induced fission fragment detectors

    International Nuclear Information System (INIS)

    Amorim, A.M.M.

    1986-01-01

    The slide glass, registered trade marks INLAB, INVICT and PERFECTA were compared. For the three kinds of glasses the following studies were done: chemical composition; general dissolution rate for hydrofluoric acid solutions of concentrations between 1 and 10M, at 30 0 C and ultrasound shaking; relative efficiency for recording fission fragment tracks from 252 Cf. The INLAB glass was selected due to the better quality of its surface after chemical etching. The HF concentration 2.5M was determined for chemical etching of INLAB glass, and the optimum etching time was chosen between 8 and 10 minutes. The thermal attenuation of latent tracks in the environmental temperature was observed for intervals uo to 31 days between the detector exposure to the fission fragment source and etching of tracks. Several methods were used for determining the detector parameters, such as: critical angle, angle of the cone and efficiency of etching. The effects of gamma irradiation from 60 Co and reactor neutrons in material properties as track detector were studied. Attenuation of latent tracks and saturation of color centers were observed for doses over 100M Rad. Since this kind of material contains uranium as impurity, uniformely distributed, slide glass were calibrated to be applied as a monitor of thermal neutron flux in nuclear reactor. (Author) [pt

  19. Investigation on the nuclear track techniques for the screening of the fissile nuclides in swipe samples

    International Nuclear Information System (INIS)

    Lee, M.H.; Park, J.H.; Song, K.

    2011-01-01

    Nuclear track techniques were investigated for the screening of fissile nuclides in swipe samples. The characteristics of fission and alpha track analysis for the uranium particles were investigated in this study. The estimation of 235 U enrichment for the uranium particles was performed by the fission track analysis. After identifying the uranium particles with fission track analysis in swipe samples, the 235 U enrichment of the uranium particles was measured by thermal ionization mass spectrometry (TIMS).

  20. A new technique to measure fission-product diffusion coefficients in UO2 fuel

    International Nuclear Information System (INIS)

    Hocking, W.H.; Verrall, R.A.; Bushby, S.J.

    1999-01-01

    This paper describes a new out-reactor technique for the measurement of fission-product diffusion rates in UO 2 . The technique accurately simulates in-reactor fission-fragment effects: a thermal diffusion that is due to localized mixing in the fission track, radiation-enhanced diffusion that is due to point-defect creation by fission fragments, and bubble resolution. The technique utilizes heavy-ion accelerators - low energy (40 keV to 1 MeV) for fission-product implantation, high energy (72 MeV) to create fission-fragment damage effects, and secondary ion mass spectrometry (SIMS) for measuring the depth profile of the implanted species. Preliminary results are presented from annealing tests (not in the 72 MeV ion flux) at 1465 deg. C and 1650 deg. C at low and high concentrations of fission products. (author)

  1. Photofission observations in reactor environments using selected fission-product yields

    International Nuclear Information System (INIS)

    Gold, R.; Ruddy, F.H.; Roberts, J.H.

    1982-01-01

    A new method for the observation of photofission in reactor environments is advanced. It is based on the in-situ observation of fission product yield. In fact, at a given in-situ reactor location, the fission product yield is simply a weighted linear combination of the photofission product yield, Y/sub gamma/, and the neutron induced fission product yield, Y/sub n. The weight factors arising in this linear combination are the photofission fraction and neutron induced fission fraction, respectively. This method can be readily implemented with established techniques for measuring in-situ reactor fission product yield. For example, one can use the method based on simultaneous irradiation of radiometric (RM) and solid state track recorder (SSTR) fission monitors. The sensitivity and accuracy and current knowledge of fission product yields. Unique advantages of this method for reactor applications are emphasized

  2. Angular Momentum in Fission

    Science.gov (United States)

    Gönnenwein, F.; Bunakov, V.; Dorvaux, O.; Gagarski, A.; Guseva, I.; Hanappe, F.; Kadmensky, S.; von Kalben, J.; Khlebnikov, S.; Kinnard, V.; Kopatch, Yu.; Mutterer, M.; Nesvizhevsky, V.; Petrov, G.; Prokhorova, E.; Rubchenya, V.; Sillanpää, M.; Simpson, G.; Sokolov, V.; Soldner, T.; Stuttgé, L.; Tiourine, G.; Trzaska, W.; Tsekhanovich, I.; Wagemans, C.; Wollersheim, H.-J.; Zavarukhina, T.; Zimmer, O.

    2008-04-01

    Three novel experiments in spontaneous and thermal neutron induced fission all with a bearing on angular momentum in fission are reviewed. In the first experiment it was observed that, in the reaction 235U(n, f) with incident polarized cold neutrons, the nucleus undergoing scission is rotating. This was inferred from the shift in angular distributions of ternary particles being dependent on the orientation of neutron spin. In the second study the properties of the angular momentum of spherical fission fragments was investigated. Current theories trace the spin of fragments to their deformations allowing for collective rotational vibrations at scission. However, in particular the spherical 132Te isotope exhibits a large spin at variance with theory. Exploiting the specific properties of cold deformed fission it could be proven that, for 132Te, single particle excitations instead of collective modes are responsible for the large spin observed. In a third project a pilot study was exploring the possibility to search for an evaporation of neutrons from fragments being anisotropic in their own cm-system. Due to fragment spin this anisotropy is claimed since decades to exist. It was so far never observed. A scheme has been devised and tested were triple coincidences between a fragment and two neutrons are evaluated in a way to bring the cm-anisotropy into the foreground while getting rid of the kinematical anisotropy in the lab-system due to evaporation from moving fragments. The test was run for spontaneous fission of 252Cf.

  3. UV photofunctionalization promotes nano-biomimetic apatite deposition on titanium

    Science.gov (United States)

    Saita, Makiko; Ikeda, Takayuki; Yamada, Masahiro; Kimoto, Katsuhiko; Lee, Masaichi Chang-Il; Ogawa, Takahiro

    2016-01-01

    Background Although biomimetic apatite coating is a promising way to provide titanium with osteoconductivity, the efficiency and quality of deposition is often poor. Most titanium implants have microscale surface morphology, and an addition of nanoscale features while preserving the micromorphology may provide further biological benefit. Here, we examined the effect of ultraviolet (UV) light treatment of titanium, or photofunctionalization, on the efficacy of biomimetic apatite deposition on titanium and its biological capability. Methods and results Micro-roughed titanium disks were prepared by acid-etching with sulfuric acid. Micro-roughened disks with or without photofunctionalization (20-minute exposure to UV light) were immersed in simulated body fluid (SBF) for 1 or 5 days. Photofunctionalized titanium disks were superhydrophilic and did not form surface air bubbles when immersed in SBF, whereas non-photofunctionalized disks were hydrophobic and largely covered with air bubbles during immersion. An apatite-related signal was observed by X-ray diffraction on photofunctionalized titanium after 1 day of SBF immersion, which was equivalent to the one observed after 5 days of immersion of control titanium. Scanning electron microscopy revealed nodular apatite deposition in the valleys and at the inclines of micro-roughened structures without affecting the existing micro-configuration. Micro-roughened titanium and apatite-deposited titanium surfaces had similar roughness values. The attachment, spreading, settling, proliferation, and alkaline phosphate activity of bone marrow-derived osteoblasts were promoted on apatite-coated titanium with photofunctionalization. Conclusion UV-photofunctionalization of titanium enabled faster deposition of nanoscale biomimetic apatite, resulting in the improved biological capability compared to the similarly prepared apatite-deposited titanium without photofunctionalization. Photofunctionalization-assisted biomimetic apatite

  4. A New Measurement of Neutron Induced Fission Cross Sections

    Science.gov (United States)

    Magee, Joshua; Niffte Collaboration

    2017-09-01

    Neutron induced fission cross sections of actinides are of great interest in nuclear energy and stockpile stewardship. Traditionally, measurements of these cross sections have been made with fission chambers, which provide limited information on the actual fragments, and ultimately result in uncertainties on the order of several percent. The Neutron Induced Fission ragment Tracking Experiment (NIFFTE) collaboration designed and built a fission Time Projection Chamber (fissionTPC), which provides additional information on these processes, through 3-dimensional tracking, improved particle identification, and in-situ profiles of target and beam non-uniformities. Ultimately, this should provide sub-percent measurements of (n,f) cross-sections. During the 2016 run cycle, measurements of the 238U(n,f)/235U(n,f) cross section shape was performed at the Los Alamos Neutron Science Center (LANSCE) Weapons Neutron Research (WNR) facility. An overview of the fission TPC will be given, as well as these recently reported results. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  5. Fission fragment angular momentum

    International Nuclear Information System (INIS)

    Frenne, D. De

    1991-01-01

    Most of the energy released in fission is converted into translational kinetic energy of the fragments. The remaining excitation energy will be distributed among neutrons and gammas. An important parameter characterizing the scission configuration is the primary angular momentum of the nascent fragments. Neutron emission is not expected to decrease the spin of the fragments by more than one unit of angular momentum and is as such of less importance in the determination of the initial fragment spins. Gamma emission is a suitable tool in studying initial fragment spins because the emission time, number, energy, and multipolarity of the gammas strongly depend on the value of the primary angular momentum. The main conclusions of experiments on gamma emission were that the initial angular momentum of the fragments is large compared to the ground state spin and oriented perpendicular to the fission axis. Most of the recent information concerning initial fragment spin distributions comes from the measurement of isomeric ratios for isomeric pairs produced in fission. Although in nearly every mass chain isomers are known, only a small number are suitable for initial fission fragment spin studies. Yield and half-life considerations strongly limit the number of candidates. This has the advantage that the behavior of a specific isomeric pair can be investigated for a number of fissioning systems at different excitation energies of the fragments and fissioning nuclei. Because most of the recent information on primary angular momenta comes from measurements of isomeric ratios, the global deexcitation process of the fragments and the calculation of the initial fragment spin distribution from measured isomeric ratios are discussed here. The most important results on primary angular momentum determinations are reviewed and some theoretical approaches are given. 45 refs., 7 figs., 2 tabs

  6. Fission gas measuring technology

    International Nuclear Information System (INIS)

    Lee, Hyung Kwon; Kim, Eun Ka; Hwang, Yong Hwa; Lee, Eun Pyo; Chun, Yong Bum; Seo, Ki Seog; Park, Dea Gyu; Chu, Yong Sun; Ahn, Sang Bok.

    1998-02-01

    Safety and economy of nuclear plant are greatly affected by the integrity of nuclear fuels during irradiation reactor core. A series of post-irradiation examination (PIE) including non-destructive and destructive test is to be conducted to evaluate and characterize the nuclear performance. In this report, a principle of the examination equipment to measure and analyse fission gases existing nuclear fuels were described and features of the component and device consisting the fission gas measuring equipment are investigated. (author). 4 refs., 2 tabs., 6 figs

  7. Fission gas measuring technology

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyung Kwon; Kim, Eun Ka; Hwang, Yong Hwa; Lee, Eun Pyo; Chun, Yong Bum; Seo, Ki Seog; Park, Dea Gyu; Chu, Yong Sun; Ahn, Sang Bok

    1998-02-01

    Safety and economy of nuclear plant are greatly affected by the integrity of nuclear fuels during irradiation reactor core. A series of post-irradiation examination (PIE) including non-destructive and destructive test is to be conducted to evaluate and characterize the nuclear performance. In this report, a principle of the examination equipment to measure and analyse fission gases existing nuclear fuels were described and features of the component and device consisting the fission gas measuring equipment are investigated. (author). 4 refs., 2 tabs., 6 figs.

  8. Low energy nuclear fission

    International Nuclear Information System (INIS)

    Nifenecker, H.

    1982-02-01

    In these lectures we present the liquid drop model of fission and compare some of its prediction with experiment. The liquid drop analogy allows to define in a rather simple and intuitive way a number of useful concepts and possible observables. We then discuss, using the example of the oscillator model, the generality of shell effects. We show how a synthesis of the liquid drop model and of the shell model can be made using the Strutinsky shell averaging procedure. Some experimental data related to the existence of shape isomers are presented and discussed. We conclude by discussing some aspects, both experimental and theoretical, of fission dynamics

  9. Low energy nuclear fission

    International Nuclear Information System (INIS)

    Nifenecker, H.

    1980-08-01

    In these lectures the liquid drop model of fission is presented and some of its predictions compared with experiment. The liquid drop analogy allows to define in a rather simple and intuitive way a number of useful concepts and possible observables. It is shown how a synthesis of the liquid drop model and of the shell model can be made using the Strutinsky shell averaging procedure. Some experimental data related to the existence of shape isomers are presented and discussed. We conclude by discussing some aspects, both experimental and theoretical, of fission dynamics

  10. Fission modelling with FIFRELIN

    Energy Technology Data Exchange (ETDEWEB)

    Litaize, Olivier; Serot, Olivier; Berge, Leonie [CEA, DEN, DER, SPRC, Saint Paul Lez Durance (France)

    2015-12-15

    The nuclear fission process gives rise to the formation of fission fragments and emission of particles (n,γ, e{sup -}). The particle emission from fragments can be prompt and delayed. We present here the methods used in the FIFRELIN code, which simulates the prompt component of the de-excitation process. The methods are based on phenomenological models associated with macroscopic and/or microscopic ingredients. Input data can be provided by experiment as well as by theory. The fission fragment de-excitation can be performed within Weisskopf (uncoupled neutron and gamma emission) or a Hauser-Feshbach (coupled neutron/gamma emission) statistical theory. We usually consider five free parameters that cannot be provided by theory or experiments in order to describe the initial distributions required by the code. In a first step this set of parameters is chosen to reproduce a very limited set of target observables. In a second step we can increase the statistics to predict all other fission observables such as prompt neutron, gamma and conversion electron spectra but also their distributions as a function of any kind of parameters such as, for instance, the neutron, gamma and electron number distributions, the average prompt neutron multiplicity as a function of fission fragment mass, charge or kinetic energy, and so on. Several results related to different fissioning systems are presented in this work. The goal in the next decade will be i) to replace some macroscopic ingredients or phenomenological models by microscopic calculations when available and reliable, ii) to be a support for experimentalists in the design of detection systems or in the prediction of necessary beam time or count rates with associated statistics when measuring fragments and emitted particle in coincidence iii) extend the model to be able to run a calculation when no experimental input data are available, iv) account for multiple chance fission and gamma emission before fission, v) account for

  11. ID ICPMS Lu-Hf Geochronology of Apatite from Iron-Oxide Apatite (IOA) Deposits, Northern Chilean Iron Belt.

    Science.gov (United States)

    Zhang, C.; Vervoort, J. D.; Barra, F.; Palma, G.

    2017-12-01

    Determining the age of mineralization of ore deposits is important for understanding the mechanisms and timing of ore formation. In many cases, however, conventional dateable mineral phases (e.g., zircon, monazite) are lacking in the ore mineral assemblages. For example, Iron Oxide Apatite (IOA) and Iron Oxide Gold Copper Gold (IOCG) deposits have the remaining fundamental question as to whether they have formed by hydrothermal or magmatic processes, or some combination of the two. In these deposits, the mineralization of iron oxide is often accompanied by the growth of apatites, which typically have REE concentrations of tens to several thousand ppm and which makes them potentially amenable to dating by the Lu-Hf isochron method. These apatites, however, also have very low concentrations of Hf, which makes determination of precise Hf isotope compositions challenging. In this study, we attempted to date these deposits using the apatite Lu-Hf isochron method, using procedures modified from that of Münker et al., 2001 and Barfod et al., 2003 and report the first Lu-Hf ages for apatites from Carmen, Fresia, and Mariela IOA deposits in northern Chilean Iron Belt. The concentration of Hf in analyzed apatite is 0.001 ppm. To ensure at least 0.5ng of Hf is collected for MS analysis, 0.5g apatite was dissolved for each sample. A single stage of Ln-spec resin chromatographic columns was used to separate Hf from REEs as multi stages of separation columns would decrease the Hf yield considerably. Using these procedures, we determined a Lu-Hf apatite age for the Carmen deposit of 130.0±1.7 Ma, which is in accordance with a previously published U-Pb apatite age of 131.0±1.0 Ma (Gelcich et al., 2005). The apatites from Fresia and Mariela yield Lu-Hf ages of 132.8±5.3 Ma and 117.3±0.4 Ma respectively. The lower points on the isochrons are either a low Lu/Hf phase (actinolite, magnetite) or bulk earth ratios. These are some of the first Lu-Hf ages of directly dating apatite

  12. 60 years controlled nuclear fission: CP-1

    International Nuclear Information System (INIS)

    Anon.

    2002-01-01

    On December 2, 1942, the Chicago Pile 1 (CP-1) went critical for the first time. In this way, the scientists and engineers involved in the project under the leadership of Enrico Fermi succeeded in demonstrating that a self-sustaining nuclear reaction with nuclear fission processes was technically feasible. Only four years after the discovery and proof of nuclear fission by Otto Hahn, Fritz Strassmann, and Lise Meitner, the experiment consisting of graphite blocks as the moderator and uranium dioxide pellets as the fuel, as well as instrumentation and control devices, had been set up in the former squash court of the field and track stadium of the University of Chicago. Precisely at 3.36 a.m. Chicago time, after control rods had been withdrawn, the instruments showed the chain reaction by the neutron flux they indicated. An important cornerstone in the use of nuclear power had thus been laid. (orig.)

  13. Fragment Angular Distributions in Neutron-Induced Fission of w235U and 239Pu using a Time Projection Chamber

    Science.gov (United States)

    Kleinrath, Verena

    2014-09-01

    Fission fragment angular distributions can lend insights into fission barrier shapes and level densities at the scission point, both important for fission theory development. Fragment emission anisotropies are also valuable for precision cross section ratio measurements, if the distributions are different for the two isotopes used in the ratio. Available angular data is sparse for 235U and even more so for 239Pu, especially at neutron energies above 5 MeV. The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) time projection chamber, which enables precise tracking of charged particles, can be used to study angular distributions and emission anisotropies of fission fragments in neutron-induced fission. Analysis of in-beam data collected at the Los Alamos Neutron Science Center with a 239Pu/235U target will provide angular distributions as a function of incident neutron energy for these isotopes. Preliminary angular distributions for 235U and 239Pu using the NIFFTE time projection chamber will be presented. Fission fragment angular distributions can lend insights into fission barrier shapes and level densities at the scission point, both important for fission theory development. Fragment emission anisotropies are also valuable for precision cross section ratio measurements, if the distributions are different for the two isotopes used in the ratio. Available angular data is sparse for 235U and even more so for 239Pu, especially at neutron energies above 5 MeV. The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) time projection chamber, which enables precise tracking of charged particles, can be used to study angular distributions and emission anisotropies of fission fragments in neutron-induced fission. Analysis of in-beam data collected at the Los Alamos Neutron Science Center with a 239Pu/235U target will provide angular distributions as a function of incident neutron energy for these isotopes. Preliminary angular distributions for 235U and

  14. Development of calcium phosphate based apatite from hen's eggshell

    Indian Academy of Sciences (India)

    Unknown

    Cowin et al 1987). The apatitic calcium phosphate of bone mineral consists of carbonate, small amount of sodium, magnesium and other trace ele- ments. The submicroscopic crystal of calcium phosphate in bone resembles the crystal structure ...

  15. Discoveries of isotopes by fission

    Indian Academy of Sciences (India)

    2015-08-28

    Aug 28, 2015 ... Of the about 3000 isotopes presently known, about 20% have been discovered in fission. The history of fission as it relates to the discovery of isotopes as well as the various reaction mechanisms leading to isotope discoveries involving fission are presented.

  16. 50 years of nuclear fission

    International Nuclear Information System (INIS)

    Hilscher, D.

    1989-01-01

    The article tells the story of the discovery of nuclear fission in Berlin 50 years ago by Otto Hahn and Fritz Strassmann in cooperation with Lise Meitner. 50 years later nuclear fission is still a subject of research. Some question remain unanswered. Selected new research results are used to discuss the dynamics of the collective movement of the elementary nuclear fission process. (orig.) [de

  17. On the use of Makrofol KG to study fission fragment angular distributions

    CERN Document Server

    Chekirine, M

    1999-01-01

    Makrofol KG nuclear track detector processing and analysis is carefully regulated and assessed to reveal fission fragments' tracks and their angular distributions. For this purpose, foils of this detector are irradiated by a thin sup 2 sup 5 sup 2 Cf source and are subjected to chemical etching followed by a two-step sparking process. The detector efficiency as a function of fission fragment incidence angle and different etching parameters is carried out with a good reproducibility.

  18. Story of Fission

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 3. Story of Fission: Unlocking Power of the Nucleus. Amit Roy. General Article Volume 21 Issue 3 March 2016 pp 247-258. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/021/03/0247-0258 ...

  19. Story of Fission

    Indian Academy of Sciences (India)

    IAS Admin

    and contributes very little to global warming. The discovery of fission of uranium in 1939 changed forever the way society at large supported scientific research. Till that time, individual researchers or small groups would pursue their sub- jects of interest with whatever resources they could muster either from government or ...

  20. The discovery of fission

    International Nuclear Information System (INIS)

    McKay, H.A.C.

    1978-01-01

    In this article by the retired head of the Separation Processes Group of the Chemistry Division, Atomic Energy Research Establishment, Harwell, U.K., the author recalls what he terms 'an exciting drama, the unravelling of the nature of the atomic nucleus' in the years before the Second World War, including the discovery of fission. 12 references. (author)

  1. Insight into Biological Apatite: Physiochemical Properties and Preparation Approaches

    Directory of Open Access Journals (Sweden)

    Quan Liu

    2013-01-01

    Full Text Available Biological apatite is an inorganic calcium phosphate salt in apatite form and nano size with a biological derivation. It is also the main inorganic component of biological hard tissues such as bones and teeth of vertebrates. Consequently, biological apatite has a wide application in dentistry and orthopedics by using as dental fillers and bone substitutes for bone reconstruction and regeneration. Given this, it is of great significance to obtain a comprehensive understanding of its physiochemical and biological properties. However, upon the previous studies, inconsistent and inadequate data of such basic properties as the morphology, crystal size, chemical compositions, and solubility of biological apatite were reported. This may be ascribed to the differences in the source of raw materials that biological apatite are made from, as well as the effect of the preparation approaches. Hence, this paper is to provide some insights rather than a thorough review of the physiochemical properties as well as the advantages and drawbacks of various preparation methods of biological apatite.

  2. Insight into biological apatite: physiochemical properties and preparation approaches.

    Science.gov (United States)

    Liu, Quan; Huang, Shishu; Matinlinna, Jukka Pekka; Chen, Zhuofan; Pan, Haobo

    2013-01-01

    Biological apatite is an inorganic calcium phosphate salt in apatite form and nano size with a biological derivation. It is also the main inorganic component of biological hard tissues such as bones and teeth of vertebrates. Consequently, biological apatite has a wide application in dentistry and orthopedics by using as dental fillers and bone substitutes for bone reconstruction and regeneration. Given this, it is of great significance to obtain a comprehensive understanding of its physiochemical and biological properties. However, upon the previous studies, inconsistent and inadequate data of such basic properties as the morphology, crystal size, chemical compositions, and solubility of biological apatite were reported. This may be ascribed to the differences in the source of raw materials that biological apatite are made from, as well as the effect of the preparation approaches. Hence, this paper is to provide some insights rather than a thorough review of the physiochemical properties as well as the advantages and drawbacks of various preparation methods of biological apatite.

  3. Fission Fragment Angular Distributions measured with a Time Projection Chamber

    International Nuclear Information System (INIS)

    Kleinrath, Verena

    2015-01-01

    The subject is presented in a series of slides with the following organization: Introduction (What is anisotropy? Relevance (Theory and ratio cross section), Previous measurements); Experiment (Particle tracking in the fissionTPC, Neutron time of flight, Data analysis & uncertainty calculation, Preliminary result for 235 U); and Future Work (Refine 235 U result, Process 239 Pu data).

  4. Monte-Carlo Generation of Time Evolving Fission Chains

    Energy Technology Data Exchange (ETDEWEB)

    Verbeke, Jerome M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kim, Kenneth S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Prasad, Manoj K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Snyderman, Neal J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-08-01

    About a decade ago, a computer code was written to model neutrons from their “birth” to their final “death” in thermal neutron detectors (3He tubes): SrcSim had enough physics to track the neutrons in multiplying systems, appropriately increasing and decreasing the neutron population as they interacted by absorption, fission and leakage. The theory behind the algorithms assumed that all neutrons produced in a fission chain were all produced simultaneously, and then diffused to the neutron detectors. For cases where the diffusion times are long compared to the fission chains, SrcSim is very successful. Indeed, it works extraordinarily well for thermal neutron detectors and bare objects, because it takes tens of microseconds for fission neutrons to slow down to thermal energies, where they can be detected. Microseconds are a very long time compared to the lengths of the fission chains. However, this inherent assumption in the theory prevents its use to cases where either the fission chains are long compared to the neutron diffusion times (water-cooled nuclear reactors, or heavily moderated object, where the theory starts failing), or the fission neutrons can be detected shortly after they were produced (fast neutron detectors). For these cases, a new code needs to be written, where the underlying assumption is not made. The purpose of this report is to develop an algorithm to generate the arrival times of neutrons in fast neutron detectors, starting from a neutron source such as a spontaneous fission source (252Cf) or a multiplying source (Pu). This code will be an extension of SrcSim to cases where correlations between neutrons in the detectors are on the same or shorter time scales as the fission chains themselves.

  5. An SSNTD study of spontaneous fission fragments from the soil-gas samples of Bakreswar thermal springs

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Debasish; Ghose, Debasis; Sastri, R.C. E-mail: res@juphys.ernet.in

    2001-04-01

    During the course of investigations on the radon and stable gas migration around the hot spring zone at Bakreswar, Birbhum in India, it was noticed that CR-39 plastic detectors used for the detection of radon revealed tracks with much bigger diameters than usual for alpha particle tracks. Exposed CR-39 detectors etched adapting sequential etching technique confirmed the presence of bigger diameter tracks similar in nature to the tracks formed by spontaneous fission fragments. This paper presents the results of these observations along with the histogram plots of the track number versus track diameter that indicate an asymmetric distribution as was seen for mass distribution of spontaneous fission fragments.

  6. Membrane fission by protein crowding.

    Science.gov (United States)

    Snead, Wilton T; Hayden, Carl C; Gadok, Avinash K; Zhao, Chi; Lafer, Eileen M; Rangamani, Padmini; Stachowiak, Jeanne C

    2017-04-18

    Membrane fission, which facilitates compartmentalization of biological processes into discrete, membrane-bound volumes, is essential for cellular life. Proteins with specific structural features including constricting rings, helical scaffolds, and hydrophobic membrane insertions are thought to be the primary drivers of fission. In contrast, here we report a mechanism of fission that is independent of protein structure-steric pressure among membrane-bound proteins. In particular, random collisions among crowded proteins generate substantial pressure, which if unbalanced on the opposite membrane surface can dramatically increase membrane curvature, leading to fission. Using the endocytic protein epsin1 N-terminal homology domain (ENTH), previously thought to drive fission by hydrophobic insertion, our results show that membrane coverage correlates equally with fission regardless of the hydrophobicity of insertions. Specifically, combining FRET-based measurements of membrane coverage with multiple, independent measurements of membrane vesiculation revealed that fission became spontaneous as steric pressure increased. Further, fission efficiency remained equally potent when helices were replaced by synthetic membrane-binding motifs. These data challenge the view that hydrophobic insertions drive membrane fission, suggesting instead that the role of insertions is to anchor proteins strongly to membrane surfaces, amplifying steric pressure. In line with these conclusions, even green fluorescent protein (GFP) was able to drive fission efficiently when bound to the membrane at high coverage. Our conclusions are further strengthened by the finding that intrinsically disordered proteins, which have large hydrodynamic radii yet lack a defined structure, drove fission with substantially greater potency than smaller, structured proteins.

  7. The light transmission method of automated track scanning

    International Nuclear Information System (INIS)

    Gold, Raymond; Roberts, J.H.

    2000-01-01

    An empirical method of automated track scanning is described. This new method is based on the measurement of light transmission (LT) through solid state track recorders (SSTR). Fission fragment tracks in mica SSTR are used to demonstrate the utility of this method. Data analysis reveals that the LT method is equivalent to a point sampling method at the approximately 2% (1σ) uncertainty level of the calibration data. The total (1σ) uncertainty of the LT method decreases with increasing fission density from approximately 5% at a fission density of 4.0E + 06 fissions/cm 2 down to approximately 2.5% at a fission density of 1.2E + 07 fissions/cm 2 . The current stage of development permits only a qualitative comparison of the LT and point sampling methods. Recommendations to refine the LT method are advanced with emphasis on processing procedures for mica SSTR

  8. [Fission product yields of 60 fissioning reactions]. Final report

    International Nuclear Information System (INIS)

    Rider, B.F.

    1995-01-01

    In keeping with the statement of work, I have examined the fission product yields of 60 fissioning reactions. In co-authorship with the UTR (University Technical Representative) Talmadge R. England ''Evaluation and Compilation of Fission Product Yields 1993,'' LA-UR-94-3106(ENDF-349) October, (1994) was published. This is an evaluated set of fission product Yields for use in calculation of decay heat curves with improved accuracy has been prepared. These evaluated yields are based on all known experimental data through 1992. Unmeasured fission product yields are calculated from charge distribution, pairing effects, and isomeric state models developed at Los Alamos National Laboratory. The current evaluation has been distributed as the ENDF/B-VI fission product yield data set

  9. Apatite trace element and halogen compositions as petrogenetic-metallogenic indicators: Examples from four granite plutons in the Sanjiang region, SW China

    Science.gov (United States)

    Pan, Li-Chuan; Hu, Rui-Zhong; Wang, Xin-Song; Bi, Xian-Wu; Zhu, Jing-Jing; Li, Chusi

    2016-06-01

    The abundances of trace elements including Sr, Ga and rare earth elements (REE) and halogens in apatite crystals from four intermediate-felsic plutons in the Zhongdian terrane in the Sanjiang region have been determined using electron microprobe and laser ablation inductively coupled plasma mass spectrometry to evaluate the potential of apatite as a petrogenic-metallogenic indicator. The selected plutons include one that is not mineralized (the Triassic Xiuwacu pluton, or the TXWC pluton), one that hosts a porphyry-type Cu deposit (the Pulang pluton, or the PL pluton), one that hosts a porphyry-type Mo deposit (the Tongchanggou pluton, or the TCG pluton), and one that hosts a vein-type Mo deposit (the Cretaceous Xiuwacu pluton, or the CXWC pluton). Except for the CXWC pluton, the other three plutons have adakite-like trace element signatures in whole rocks. The results from this study show that REE, Sr and halogens in apatite can be used to track magma compositions, oxidation states and crystallization history. Apatite crystals from the adakite-like plutons are characterized by much higher Sr/Y and δEu than the non-adakite-type pluton. This means that apatite, which is not susceptible to alteration, is a useful tool for identifying the adakite-like plutons that no longer preserve the initial Sr/Y ratios in whole rocks due to weathering and hydrothermal alteration. Based on apatite Ga contents and δEu values, it is inferred that the parental magmas for the two adakite-like plutons containing porphyry-type Cu and Mo mineralization are more oxidized than that for the non-adakite-type pluton containing vein-type Mo mineralization. Apatite crystals from the vein-type Mo deposit have much lower Cl/F ratios than those from the porphyry-type Cu and Mo deposits. Apatite crystals from the adakite-like pluton without Cu or Mo mineralization is characterized by much lower Cl/F ratios than those from the adakite-like plutons that host the porphyry-type Cu and Mo deposits. The

  10. UV photofunctionalization promotes nano-biomimetic apatite deposition on titanium

    Directory of Open Access Journals (Sweden)

    Saita M

    2016-01-01

    Full Text Available Makiko Saita,1 Takayuki Ikeda,1,2 Masahiro Yamada,1,3 Katsuhiko Kimoto,4 Masaichi Chang-Il Lee,5 Takahiro Ogawa1 1Division of Advanced Prosthodontics, Weintraub Center for Reconstructive Biotechnology, UCLA School of Dentistry, Los Angeles, CA, USA; 2Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Yokosuka, Japan; 3Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan; 4Department of Prosthodontics and Oral Rehabilitation, 5Yokosuka-Shonan Disaster Health Emergency Research Center and ESR Laboratories, Kanagawa Dental University Graduate School of Dentistry, Yokosuka, Japan Background: Although biomimetic apatite coating is a promising way to provide titanium with osteoconductivity, the efficiency and quality of deposition is often poor. Most titanium implants have microscale surface morphology, and an addition of nanoscale features while preserving the micromorphology may provide further biological benefit. Here, we examined the effect of ultraviolet (UV light treatment of titanium, or photofunctionalization, on the efficacy of biomimetic apatite deposition on titanium and its biological capability.Methods and results: Micro-roughed titanium disks were prepared by acid-etching with sulfuric acid. Micro-roughened disks with or without photofunctionalization (20-minute exposure to UV light were immersed in simulated body fluid (SBF for 1 or 5 days. Photofunctionalized titanium disks were superhydrophilic and did not form surface air bubbles when immersed in SBF, whereas non-photofunctionalized disks were hydrophobic and largely covered with air bubbles during immersion. An apatite-related signal was observed by X-ray diffraction on photofunctionalized titanium after 1 day of SBF immersion, which was equivalent to the one observed after 5 days of immersion of control titanium. Scanning electron microscopy revealed nodular apatite deposition

  11. Biological effectiveness of fission neutrons

    International Nuclear Information System (INIS)

    Sasaki, M.S.; Saigusa, S.; Kimura, I.

    1992-01-01

    Human peripheral blood lymphocytes were exposed to the uranium fission neutrons with different energy spectra, and the effects of changing pattern of energy spectrum on the relative biological effectiveness (RBE) were studied by analyzing dose-response relationship of chromosome aberrations. When the contribution of contaminated gamma-rays was subtracted, the efficiency of chromosomal response to the neutron dose was found to be refractory to the difference in the energy spectrum while the mean energy ranged from 2 MeV to 27 keV. This chromosomal refractoriness to energy spectrum may be explained by the similarity of energy spectrum for kerma contribution; most of the doses being given by neutrons with energy above 50 keV. Small doses given by short tracks may be less efficient. A comparison of these observations with chromosome aberration frequencies in lymphocytes of A-bomb survivors leads to somewhat higher estimate of neutron dose in Hiroshima than the estimate by the recently revised dosimetry system, DS86. (author)

  12. Study on apatite compounds; Apataitokei kagobutsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-11-28

    To clarify the material properties of apatite compounds, the synthesis method, and the evaluation of physical properties of material and elementary technology were investigated. For the study on synthesis and crystal growth, a method of precipitating calcium phosphate on the surface of metal was investigated by means of relatively mild electrolytic method using liquid phase system. A new molding method of Ca defective apatite was established. Composite similar to vital bone was prepared by means of a new low-temperature sintering. For the study on chemical properties, from the model experiments, it was found that the self-organizing phenomenon, which is observed in the composite of apatite and collagen, happened between the organic single molecular film and crystal of apatite. For the study on evaluation of physical properties and elementary technology, the surface and interface of ceramics such as apatite were investigated by means of spectroscopy, the electronic state was analyzed by the quantum chemical calculation, and the crystalline structure was analyzed using X-ray equipment. 270 refs., 102 figs., 10 tabs.

  13. Neutron emission anisotropy in fission

    OpenAIRE

    CHIETERA A.; STUTTGE L.; GOENNENWEIN F.; KOPATCH Y.; MUTTERER M.; GUSEVA I.; GAGARSKI A.; CHERNYSHEVA E; DORVAUX O; HAMBSCH Franz-Josef; HANAPPE F.; MEZENTSEVAH Z.; TELEZHNIKOVCH S.

    2015-01-01

    Experimental neutron angular distributions are investigated in the spontaneous fission process of 252Cf. The CORA experiment, presented in this paper, has the aim to study neutron angular correlations in order to elucidate the neutron emission mechanisms in the fission process. The experimental setup is composed by the CODIS fission chamber and the DEMON neutron multidetector. The development of a simulation toolkit based on GEANT4 and ROOT adopted as strategy to investigate the emission of t...

  14. Nuclear Forensics and Radiochemistry: Fission

    Energy Technology Data Exchange (ETDEWEB)

    Rundberg, Robert S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-11-07

    Radiochemistry has been used to study fission since it’ discovery. Radiochemical methods are used to determine cumulative mass yields. These measurements have led to the two-mode fission hypothesis to model the neutron energy dependence of fission product yields. Fission product yields can be used for the nuclear forensics of nuclear explosions. The mass yield curve depends on both the fuel and the neutron spectrum of a device. Recent studies have shown that the nuclear structure of the compound nucleus can affect the mass yield distribution.

  15. Micro plate fission chamber development

    International Nuclear Information System (INIS)

    Wang Mei; Wen Zhongwei; Lin Jufang; Jiang Li; Liu Rong; Wang Dalun

    2014-01-01

    To conduct the measurement of neutron flux and the fission rate distribution at several position in assemblies, the micro plate fission chamber was designed and fabricated. Since the requirement of smaller volume and less structure material was taken into consideration, it is convinient, commercial and practical to use fission chamber to measure neutron flux in specific condition. In this paper, the structure of fission chamber and process of fabrication were introduced and performance test result was presented. The detection efficiency is 91.7%. (authors)

  16. Chemical, physical, and histologic studies on four commercial apatites used for alveolar ridge augmentation

    DEFF Research Database (Denmark)

    Pinholt, E M; Ruyter, I E; Haanaes, H R

    1992-01-01

    characteristics obtained by chemical analysis and infrared spectrometry. None of the apatites caused osteoinduction or osteoconduction; fibrous encapsulation with multinuclear giant cells was observed around all four types. One of the apatites was fluorapatite and not hydroxylapatite, as claimed...

  17. Electrochemical Studies of Paraquat Adsorbed onto Crystalline Apatite

    Directory of Open Access Journals (Sweden)

    Moulay Abderrahim EL MHAMMEDI

    2007-09-01

    Full Text Available The carbon paste electrode (CPE has been used to analyze the electrochemical behavior of paraquat (PQ adsorbed onto synthesized hydroxyapatite phosphocalcique (HAP in K2SO4 (0.1M. The cyclic voltammetry results obtained corrobate with square wave voltammetry. The influence of variables such as the concentration of paraquat adsorbed onto apatite (PQ/HAP, and the potential scan rate was tested.X-ray diffraction analysis (XRD, Fourier transformed infrared spectroscopy (FTIR analysis and inductively coupled plasma-atomic emission spectrometry (ICP, AES were used for characterization of the apatite.

  18. Tip model of cold fission

    International Nuclear Information System (INIS)

    Goennenwein, F.; Boersig, B.

    1991-01-01

    Cold fission is defined to be the limiting case of nuclear fission where virtually all of the available energy is converted into the total kinetic energy of the fragments. The fragments have, therefore, to be born in or at least close to their respective ground states. Starting from the viewpoint that cold fission corresponds to most compact scission configurations, energy constraints have been exploited to calculate minimum tip distances between the two nascent fragments in binary fission. Crucial input parameters to this tip model of cold fission are the ground-state deformations of fragment nuclei. It is shown that the minimum tip distances being compatible with energy conservation vary strongly with both the mass and charge fragmentation of the fission prone nucleus. The tip distances refer to nuclei with equivalent sharp surfaces. In keeping with the size of the surface width of leptodermous nuclei, only configurations where the tip distances are smaller than a few fm may be considered as valid scission configurations. From a comparison with experimental data on cold fission this critical tip distance appears to be 3.0 fm for the model parameters chosen. Whenever the model calculation yields tip distances being smaller than the critical value, a necessary condition for attaining cold fission is considered to be fulfilled. It is shown that this criterion allows to understand in fair agreement with experiment which mass fragmentations are susceptible to lead to cold fission and which fragment-charge divisions are the most favored in each isobaric mass chain. Being based merely on energy arguments, the model cannot aim at predicting fragment yields in cold fission. However, the tip model proposed appears well suited to delineate the phase space where cold fission phenomena may come into sight. (orig.)

  19. Post-scission fission theory: Neutron emission in fission

    International Nuclear Information System (INIS)

    Madland, D.G.

    1997-01-01

    A survey of theoretical representations of two of the observables in neutron emission in fission is given, namely, the prompt fission neutron spectrum N (E) and the average prompt neutron multiplicity bar ν p . Early representations of the two observables are presented and their deficiencies are discussed. This is followed by summaries and examples of recent theoretical models for the calculation of these quantities. Emphasis is placed upon the predictability and accuracy of the recent models. In particular, the dependencies of N (E) and bar ν p upon the fissioning nucleus and its excitation energy are treated. Recent work in the calculation of the prompt fission neutron spectrum matrix N (E, E n ), where E n is the energy of the neutron inducing fission, is then discussed. Concluding remarks address the current status of our ability to calculate these observables with confidence, the direction of future theoretical efforts, and limitations to current (and future) approaches

  20. Fission hindrance and nuclear viscosity

    Indian Academy of Sciences (India)

    viscosity in slowing down the diffusion rate in comparison to the decay rate without vis- cosity predicted by Bohr and ... revived Kramers' dynamical approach to understand nuclear fission at finite temperature and angular momentum. ... tor and (2) a compact seven-element array of BaF2 detectors. The fission fragments were.

  1. Discoveries of isotopes by fission

    Indian Academy of Sciences (India)

    also contributed to the discovery of new isotopes. More recently, most of the very neutron- rich isotopes have been discovered by projectile fission. After a brief summary of the discovery of fission process itself, these production mechanisms will be discussed. The paper concludes with an outlook on future discoveries of ...

  2. Fission throughout the periodic table

    International Nuclear Information System (INIS)

    Moretto, L.G.; Wozniak, G.J.

    1989-04-01

    The dualistic view of fission and evaporation as two distinct compound nucleus processes is substituted with a unified view in which fission, complex fragment emission, and light particle evaporation are seen as different aspects of a single process. 47 refs., 22 figs

  3. Progress in fission product nuclear data

    International Nuclear Information System (INIS)

    Lammer, M.

    1984-09-01

    This is the tenth issue of a report series on Fission Product Data, which informs us about all the activities in this field, which are planned, ongoing, or have recently been completed. The types of activities included are measurements, compilations and evaluations of: fission product yields (neutron induced and spontaneous fission), neutron reaction cross sections of fission products, data related to the radioactive decay of fission products, delayed neutron data of fission products, lumped fission product data (decay heat, absorption, etc.). There is also a section with recent references relative to fission product nuclear data

  4. Industrial use of fission products

    International Nuclear Information System (INIS)

    Silverman, J.

    1989-01-01

    Perhaps the most disappointing and surprising development in the fifty year history of nuclear fission is the small role fission products play in modern technology. As a large and potentially inexpensive source of ionizing radiation, fission products were expected to offer major practical benefits. The attractive opportunities stimulated imaginative efforts to realize their fulfillment, but their direct impact has been minor. Fission products have not fared well, not only in somewhat indirect competition with nonradioactive alternatives, but also in direct competition with other radiation sources, especially electron accelerators and 60 Co. There is one major triumph for fission product technology: the application of 99 Mo and its daughter 99m Tc as an almost universal tracer system in nuclear medicine

  5. Mechanisms of fission neutron emission

    International Nuclear Information System (INIS)

    Maerten, H.

    1991-01-01

    The time evolution in fission is the starting point for discussing not only the main mechanism of fission neutron emission, the evaporation from fully accelerated fragments, but also possible secondary ones connected with dynamical features of nuclear fission. ''Asymptotic'' conditions as relevant for describing the particle release from highly excited, rapidly moving fragments are defined. Corresponding statistical model approaches to fission neutron emission, based on the adequate consideration of the intricate fragment occurrence probability, reproduce most of the experimental data. The remarkable influence of fission modes on neutron observables is analyzed in the framework of a macroscopic-microscopic scission point model consistent with energy conservation. Finally, chances and deficiencies for solving the mechanism puzzle are summarized. (author). 87 refs, 21 figs

  6. Ternary fission and cluster radioactivities

    CERN Document Server

    Poenaru, D N; Greiner, W; Gherghescu, R A; Hamilton, J H; Ramayya, A V

    2002-01-01

    Ternary fission yield for different kinds of light particle accompanied fission processes is compared to the Q-values for the corresponding cold phenomena, showing a striking correlation. The experimental evidence for the existence of a quasimolecular state in sup 1 sup 0 Be accompanied fission of sup 2 sup 5 sup 2 Cf may be explained using a three-center phenomenological model which generates a third minimum in the deformation energy at a separation distance very close to the touching point. This model is a natural extension of the unified approach to three groups of binary decay modes (cold fission, cluster radioactivities and alpha decay), illustrated by sup 2 sup 3 sup 4 U decay modes, and the alpha valley on the potential energy surfaces of sup 1 sup 0 sup 6 Te. New measurements of cluster decay modes, confirming earlier predictions within analytical superasymmetric fission model, are included in a comprehensive half-life systematics. (authors)

  7. Nano-apatite/polymer composites: mechanical and physicochemical characteristics

    NARCIS (Netherlands)

    Liu, Qing; de Wijn, J.R.; van Blitterswijk, Clemens

    1997-01-01

    Hydrothermally synthesized acicular nano-apatite (Nap) was used as filler to make composites with a polyethylene glycol/poly(butylene terephthalate) (PEG/PBT) block copolymer (Polyactive™70:30). The Nap had a particle diameter of 9–25 nm and a length of 80–200 nm. The mechanical properties and the

  8. Lead Speciation and Bioavailability in Apatite-Amended Sediments

    Directory of Open Access Journals (Sweden)

    Kirk G. Scheckel

    2011-01-01

    Full Text Available The in situ sequestration of lead (Pb in sediment with a phosphate amendment was investigated by Pb speciation and bioavailability. Sediment Pb in preamendment samples was identified as galena (PbS with trace amounts of absorbed Pb. Sediment exposed to atmospheric conditions underwent conversion to hydrocerussite and anglesite. Sediments mixed with apatite exhibited limited conversion to pyromorphite, the hypothesized end product. Conversion of PbS to pyromorphite is inhibited under reducing conditions, and pyromorphite formation appears limited to reaction with pore water Pb and PbS oxidation products. Porewater Pb values were decreased by 94% or more when sediment was amended with apatite. The acute toxicity of the sediment Pb was evaluated with Hyalella azteca and bioaccumulation of Pb with Lumbriculus variegatus. The growth of H. azteca may be mildly inhibited in contaminated sediment, with apatite-amended sediments exhibiting on average a higher growth weight by approximately 20%. The bioaccumulation of Pb in L. variegatus tissue decreased with increased phosphate loading in contaminated sediment. The study indicates limited effectiveness of apatite in sequestering Pb if present as PbS under reducing conditions, but sequestration of porewater Pb and stabilization of near-surface sediment may be a feasible and alternative approach to decreasing potential toxicity of Pb.

  9. Thermodynamic basis for evolution of apatite in calcified tissues (Invited)

    Science.gov (United States)

    Navrotsky, A.; Drouet, C.; Rollin-Martinet, S.; Champion, E.; Grossin, D.

    2013-12-01

    Bone remodeling and tooth enamel maturation are biological processes which alter the physico-chemical features of biominerals with time. However, although the ubiquity of bone remodeling is clear, why is well crystallized bone mineral systematically replaced by immature nanocrystalline inorganic material? In enamel, a clear evolution is also seen from the first mineral formed during the secretory stage to its mature well crystalline form, which then changes little in the adult tooth. This contribution provides the thermodynamic basis underlying these biological processes. We determined the energetics of biomimetic apatites corresponding to an increasing degree of maturation. Our data point out the progressive evolution of the enthalpy (ΔHf°) and free energy (ΔGf°) of formation toward more negative values upon maturation. Entropy contributions to ΔGf° values are small compared to enthalpy contributions. ΔHf° varies from -12058.9 × 12.2 to -12771.0 × 21.4 kJ/mol for maturation times increasing from 20 min to 3 weeks, approaching the value for stoichiometric hydroxyapatite, -13431.0 × 22.7 kJ/mol. Apatite thermodynamic stability increases as its composition moved toward stoichiometry. These findings imply diminishing aqueous solubility of calcium and phosphate ions as well as decreased surface reactivity. Such thermodynamically-driven maturation is favorable for enamel maturation since this biomineral must resist external aggressions such as contact with acids. In contrast, maintaining a metastable highly reactive and soluble form of apatite is essential to the effective participation of bone as a source of calcium and phosphate for homeostasis. Therefore our data strongly suggest that, far from being trivial, the intrinsic thermodynamic properties of apatite represent a critical driving force for continuous bone remodeling, in contrast to current views favoring a purely biologically driven cycle. These thermodynamic data may prove helpful in other domains

  10. Fission fragment angular distribution in heavy ion induced fission

    Directory of Open Access Journals (Sweden)

    S. Soheyli

    2006-06-01

    Full Text Available   We have calculated the fission fragment angular anisotropy for 16O + 232Th,12C + 236U , 11B + 237 Np , 14 N + 232 Th , 11B + 235U , 12C + 232Th systems with the saddle point statistical model and compared the fission fragment angular anisotropy for these systems. This comparison was done with two methods a without neutron correction and b with neutron correction. Also we studied normal and anomalous behavior of the fission fragment angular anisotropy. Finally, we have predicted the average emitted neutron from compound nuclei considering the best fit for each system.

  11. Fission fragment angular distribution in heavy ion induced fission

    OpenAIRE

    S. Soheyli; I. Ziaeian

    2006-01-01

      We have calculated the fission fragment angular anisotropy for 16O + 232Th,12C + 236U , 11B + 237 Np , 14 N + 232 Th , 11B + 235U , 12C + 232Th systems with the saddle point statistical model and compared the fission fragment angular anisotropy for these systems. This comparison was done with two methods a) without neutron correction and b) with neutron correction. Also we studied normal and anomalous behavior of the fission fragment angular anisotropy. Finally, we have predicted the averag...

  12. Dynamical excitation in fission

    International Nuclear Information System (INIS)

    Ledergerber, T.; Paltiel, Z.; Fraenkel, Z.; Pauli, H.C.

    1976-01-01

    The excitation mechanism of the fission process is studied in terms of a model of particles moving in a deformed time-dependent potential. A residual interaction of the pairing type is incoporated by means of the BCS approximation. Only 2-quasi-particle excitations up to some cutoff energy are included. The separation of the total excitation energy into intrinsic and translational parts is made at the scission point. The present calculations for 240 Pu show that, in the framework of this model, most of the available energy at scission is transformed into intrinsic excitation energy. However the convergence of the calculated value for the cutoff energy is unsatisfactory and hence a description in terms of a better model space is needed. The fact that very many channels are involved suggests that a statistical treatment may be useful. (author)

  13. Efficiency calibration of solid track spark auto counter

    International Nuclear Information System (INIS)

    Wang Mei; Wen Zhongwei; Lin Jufang; Liu Rong; Jiang Li; Lu Xinxin; Zhu Tonghua

    2008-01-01

    The factors influencing detection efficiency of solid track spark auto counter were analyzed, and the best etch condition and parameters of charge were also reconfirmed. With small plate fission ionization chamber, the efficiency of solid track spark auto counter at various experiment assemblies was re-calibrated. The efficiency of solid track spark auto counter at various experimental conditions was obtained. (authors)

  14. The spectroscopy of fission fragments

    International Nuclear Information System (INIS)

    Phillips, W.R.

    1998-01-01

    High-resolution measurements on γ rays from fission fragments have provided a rich source of information, unobtainable at the moment in any other way, on the spectroscopy of neutron-rich nuclei. In recent years important data have been obtained on the yrast- and near yrast-structure of neutron-rich fission fragments. We discuss the scope of measurements which can be made on prompt gamma rays from secondary fission fragments, the techniques used in the experiments and some results recently obtained. (author)

  15. The spectroscopy of fission fragments

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, W.R. [Department of Physics and Astronomy, University of Manchester, Manchester, M13 9PL (United Kingdom); Collaboration: La Direction des Sciences de la Matiere du CEA (FR); Le Fonds National de la Recherche Scientifique de Belgique (BE)

    1998-12-31

    High-resolution measurements on {gamma} rays from fission fragments have provided a rich source of information, unobtainable at the moment in any other way, on the spectroscopy of neutron-rich nuclei. In recent years important data have been obtained on the yrast- and near yrast-structure of neutron-rich fission fragments. We discuss the scope of measurements which can be made on prompt gamma rays from secondary fission fragments, the techniques used in the experiments and some results recently obtained. (author) 24 refs., 8 figs., 1 tab.

  16. Investigations of fissionable elements in the Turkish fluorites

    International Nuclear Information System (INIS)

    Tret'yakova, S.P.; Oganesyan, Yu.Ts.; Merkina, K.I.; Belov, A.G.; Ponomarenko, V.A.; Bolcal, C.; Guzel, T.; Saritepe, P.

    1996-01-01

    Content of uranium and thorium elements in fluorite samples from different 'Fluorite Beds' of Turkey has been determined. Both, neutron radiography and alpha autoradiography in combination with solid state nuclear track detectors were used. It was found that fissionable elements concentration in the Turkish fluorite samples contains from 10 -4 to 10 -7 g/g. The obtained Th/U ratio for all fluorite samples is different and varies practically from 0 to 13. 5 refs., 3 figs., 1 tab

  17. Fission Fragment Angular Distributions measured with a Time Projection Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Kleinrath, Verena [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-04-28

    The subject is presented in a series of slides with the following organization: Introduction (What is anisotropy? Relevance (Theory and ratio cross section), Previous measurements); Experiment (Particle tracking in the fissionTPC, Neutron time of flight, Data analysis & uncertainty calculation, Preliminary result for 235U); and Future Work (Refine 235U result, Process 239Pu data).

  18. Biomimetic synthesis and biocompatibility evaluation of carbonated apatites template-mediated by heparin

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Yi [Department of Oral and Maxillofacial Surgery, Laboratory of Interdisciplinary Studies, School and Hospital of Stomatology, Peking University, Beijing 100081 (China); Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Sun, Yuhua [Department of Oral and Maxillofacial Surgery, Laboratory of Interdisciplinary Studies, School and Hospital of Stomatology, Peking University, Beijing 100081 (China); Chen, Xiaofang [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zhu, Peizhi, E-mail: pzzhu@umich.edu [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055 (United States); Wei, Shicheng, E-mail: sc-wei@pku.edu.cn [Department of Oral and Maxillofacial Surgery, Laboratory of Interdisciplinary Studies, School and Hospital of Stomatology, Peking University, Beijing 100081 (China); Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China)

    2013-07-01

    Biomimetic synthesis of carbonated apatites with good biocompatibility is a promising strategy for the broadening application of apatites for bone tissue engineering. Most researchers were interested in collagen or gelatin-based templates for synthesis of apatite minerals. Inspired by recent findings about the important role of polysaccharides in bone biomineralization, here we reported that heparin, a mucopolysaccharide, was used to synthesize carbonated apatites in vitro. The results indicated that the Ca/P ratio, carbon content, crystallinity and morphology of the apatites varied depending on the heparin concentration and the initial pH value. The morphology of apatite changed from flake-shaped to needle-shaped, and the degree of crystallinity decreased with the increasing of heparin concentration. Biocompatibility of the apatites was tested by proliferation and alkaline phosphatase activity of MC3T3-E1 cells. The results suggested that carbonated apatites synthesized in the presence of heparin were more favorable to the proliferation and differentiation of MC3T3-E1 cells compared with traditional method. In summary, the heparin concentration and the initial pH value play a key role in the chemical constitution and morphology, as well as biological properties of apatites. These biocompatible nano-apatite crystals hold great potential to be applied as bioactive materials for bone tissue engineering. - Highlights: • Heparin was used as a template to synthesize needle-shaped nano-apatite. • Changing the pH value and concentration led to different properties of apatite. • Apatite prepared by heparin was more favorable to the osteogenic differentiation. • Possible synthesis mechanism of apatite templated by heparin was described.

  19. Physics and chemistry of fission

    International Nuclear Information System (INIS)

    1979-01-01

    Full text: In the pleasant and hospitable atmosphere of the Kernforschungsanlage Juelich in the Federal Republic of Germany, the IAEA symposium on the Physics and Chemistry of Fission took place. Almost 200 scientists attended, 154 abstracts were submitted, and 57 papers presented, but more important than the numbers was the quality of the contributions and the progress reported at the symposium. The neutron was discovered almost 50 years ago; 40 years ago the idea of nuclear fission was born. Since then, a number of laboratories have worked hard to explain the phenomenon of fission One would expect that by now scientists would know exactly what happens in a nucleus before and during the process of fission, particularly as there are hundreds of power and research reactors in operation, and fission of uranium isotopes is the basis of their functioning. At first glance, fission seems a simple process: a neutron hits and penetrates the uranium nucleus which becomes excited, i.e. has a surplus of energy. One way to get rid of this energy is for the nucleus to split into two parts; additional products of this process are energy and more neutrons. Nature, however, seems to dislike such straightforward explanations. In the case of fission, scientists have observed a number of phenomena which disagree with a simple model. Sometimes, a nucleus will split into two parts without being 'attacked' by a neutron; this spontaneous fission opens up a new line of fission research and several contributions at the symposium reported on sophisticated experiments designed to unravel some of its specific details. Sometimes, a fissioning nucleus will emit another particle: ternary fission has become a powerful tool for studying the properties of nuclei during the fission process. For the scientist, it is fascinating to observe how the nucleus behaves during fission. They invent models which are supposed to reproduce the most probable course of events leading to fission. In one of these

  20. Theory of nuclear fission: a review

    International Nuclear Information System (INIS)

    Mosel, U.

    1976-01-01

    General properties of nuclear fission are reviewed and related to our present knowledge of fission theory. For this purpose the basic reasons for the shape of the fission barriers are discussed and their consequences compared with experimental results on barrier shapes and structures. Special emphasis is put on the asymmetry of the fission barriers and mass-distributions and its relation to the shells of the nascent fragment shells. Finally the problem of calculating fission cross sections is discussed

  1. International handling of fissionable material

    International Nuclear Information System (INIS)

    1975-01-01

    The opinion of the ministry for foreign affairs on international handling of fissionable materials is given. As an introduction a survey is given of the possibilities to produce nuclear weapons from materials used in or produced by power reactors. Principles for international control of fissionable materials are given. International agreements against proliferation of nuclear weapons are surveyed and methods to improve them are proposed. (K.K.)

  2. Preparation and Characterization of Apatitic Biphasic Calcium Phosphate

    International Nuclear Information System (INIS)

    Thin Thin Nwe; Kyaw Naing; Khin Mar Tun; Nyunt Wynn

    2005-09-01

    The apatitic biphasic calcium phosphate (ABcp) consisting of hydroxyapatite (HA) and -tricalcium phosphate ( -Tcp) has been prepared by precipitation technique using slaked lime and orthophosphoric acid. The X-ray diffraction analysis of the product I (hydroxyapatite) revealed that ABcp was partially crystalline state. However, on heating at 800 C for 8 hrs, XRD pattern indicated a perfectly crystalline form of ABcp. This observation was supported by FT-IR measurement. The change in morphology regarding in the functional nature was infered by the shift in the FT-IR frequency. The optimization of the apatitic biphasic calcium phosphate was done by the variation of disodium hydrogen phosphate concentration, setting time, hardening time as well as compressive strength. The perpared cement may be used as an artificial substitution bone

  3. Preparation of rare earth fluorides from apatite concentrate

    International Nuclear Information System (INIS)

    Mulyarchuk, I.F.; Voloshchenko, M.V.; Zen'kovich, E.G.; Sumenkova, V.V.; AN Ukrainskoj SSR, Kiev. Inst. Problem Lit'ya)

    1980-01-01

    The processes of preparation of the rare earths element sum from apatite concentrate of the Khibins, connected with preliminary extraction of rare earth phosphates from nitric acid extract using solvent extraction or direct precipitation from the extract by solution of potassium and ammonium fluorides. The sequence of the processes of the first variant is the following: solvent extraction of rare earths by tributylphosphate from clarified nitric acid extract of apatite with subsequent reextraction of rare earths with water and precipitation of rare earth phosphates from aqueous solution during neutralization by ammonia. In case of fluoride preparation from rare earth phosphate the main attention is paid to precipitation and filtration of fluorides. Technological scheme and cost price of industry for the production of 1800 t of rare earth trifluorides a year are calculated. When taking account of TBP losses according to its solubility the industry cost price is 1O times lower the modern cost of rare earth fluorides

  4. Radiochemistry and the Study of Fission

    Energy Technology Data Exchange (ETDEWEB)

    Rundberg, Robert S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-11-14

    These are slides from a lecture given at UC Berkeley. Radiochemistry has been used to study fission since its discovery. Radiochemical methods are used to determine cumulative mass yields. These measurements have led to the two-mode fission hypothesis to model the neutron energy dependence of fission product yields. Fission product yields can be used for the nuclear forensics of nuclear explosions. The mass yield curve depends on both the fuel and the neutron spectrum of a device. Recent studies have shown that the nuclear structure of the compound nucleus can affect the mass yield distribution. The following topics are covered: In the beginning: the discovery of fission; forensics using fission products: what can be learned from fission products, definitions of R-values and Q-values, fission bases, K-factors and fission chambers, limitations; the neutron energy dependence of the mass yield distribution (the two mode fission hypothesis); the influence of nuclear structure on the mass yield distribution. In summary: Radiochemistry has been used to study fission since its discovery. Radiochemical measurement of fission product yields have provided the highest precision data for developing fission models and for nuclear forensics. The two-mode fission hypothesis provides a description of the neutron energy dependence of the mass yield curve. However, data is still rather sparse and more work is needed near second and third chance fission. Radiochemical measurements have provided evidence for the importance of nuclear states in the compound nucleus in predicting the mass yield curve in the resonance region.

  5. Radiochemistry and the Study of Fission

    International Nuclear Information System (INIS)

    Rundberg, Robert S.

    2016-01-01

    These are slides from a lecture given at UC Berkeley. Radiochemistry has been used to study fission since its discovery. Radiochemical methods are used to determine cumulative mass yields. These measurements have led to the two-mode fission hypothesis to model the neutron energy dependence of fission product yields. Fission product yields can be used for the nuclear forensics of nuclear explosions. The mass yield curve depends on both the fuel and the neutron spectrum of a device. Recent studies have shown that the nuclear structure of the compound nucleus can affect the mass yield distribution. The following topics are covered: In the beginning: the discovery of fission; forensics using fission products: what can be learned from fission products, definitions of R-values and Q-values, fission bases, K-factors and fission chambers, limitations; the neutron energy dependence of the mass yield distribution (the two mode fission hypothesis); the influence of nuclear structure on the mass yield distribution. In summary: Radiochemistry has been used to study fission since its discovery. Radiochemical measurement of fission product yields have provided the highest precision data for developing fission models and for nuclear forensics. The two-mode fission hypothesis provides a description of the neutron energy dependence of the mass yield curve. However, data is still rather sparse and more work is needed near second and third chance fission. Radiochemical measurements have provided evidence for the importance of nuclear states in the compound nucleus in predicting the mass yield curve in the resonance region.

  6. Instrumental neutron activation analysis of apatite-nepheline ores

    International Nuclear Information System (INIS)

    Zajtsev, E.I.; Bakhmatov, B.A.; Lyapunov, S.M.; Sotskov, Yu.P.

    1977-01-01

    Described is the technique for neutron activation determination of rare elements (cerium, samariu, europium, terbium, ytterbium et al.) in apatite-nepheline ores using Ge(Li)-spectrometer. The effect of interference is studied, the recognition threshold and accuracy of analysis of the above elements in this ores are estimated. The technique developed are recommended for the calculation of rare earth element reserves in phosphate raw products

  7. Status of fission power

    International Nuclear Information System (INIS)

    Levenson, M.

    1977-01-01

    Fission energy is reviewed from the viewpoints of technology, economics, politics, manufacturers, consumers, and foreign countries. Technically, the reactor program is operating and the light water reactor industry shows signs of maturing, although recent business has been disappointing. Marketing of gas-cooled reactors depends, not on technical, but economic and political issues. Liquid metal fast breeder reactors have been demonstrated worldwide, while the gas-cooled fast breeder remains an undemonstrated option. Nuclear plants, currently costing the same as coal plants with scrubbers, are the cheapest option for utilities because most of the cost is imbedded. The defeat of nuclear initiatives in seven states indicates that public feeling is not as anti-nuclear as opponents to nuclear power claim. The harshness of last winter demonstrated the advantages of a power source that is not so sensitive to the weather for reliable operation and transport, as well as low cost energy. Other nations are proceeding to build a nuclear capability, which the U.S. may jeopardize because of concerns about the fuel cycle, nuclear waste disposal, uranium reserves, and nuclear proliferation

  8. Influence of agitation intensity on flotation rate of apatite particles

    Directory of Open Access Journals (Sweden)

    Francisco Gregianin Testa

    Full Text Available Abstract The agitation intensity has a directly influence on flotation performance, lifting the particles and promoting the contact of bubbles and particles. In this paper, the energy input by the agitation on apatite flotation was investigated. The influence of pulp agitation in the flotation rate of particles with different sizes and two dosage levels was evaluated by batch testing. The flotation tests were conducted in an oscillating grid flotation cell (OGC, developed to promote a near isotropic turbulence environment. The cell is able to control the intensity of agitation and measure the energy transferred to the pulp phase. A sample of pure apatite was crushed (P80=310µm, characterized and floated with sodium oleate as collector. Four levels of energy dissipation, from 0.1 to 2 kWm-3, and two levels of collector dosage are used during the tests. The flotation kinetics by particle size were determined in function of the energy transferred. The results show a strong influence of the agitation intensity on the apatite flotation rate with both low and high dosage. For fine particles, when increasing the energy input, the flotation rate increase too, and this fact can be attributed to elevation of bubble-particle collisions. The kinetic result for the coarse particles demonstrated a reduction of the flotation rate whenever the energy input for this particle size was increased, whereby the turbulence caused by the agitation promotes the detachment of bubble-particle.

  9. Fragment Angular Distributions in Neutron-Induced Fission of {sup 235}U and {sup 239}Pu using a Time Projection Chamber

    Energy Technology Data Exchange (ETDEWEB)

    Kleinrath, Verena [NIFFTE collaboration, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2015-07-01

    Fission fragment angular distributions can lend insights into fission barrier shapes and level densities at the scission point, both important for fission theory development. Fragment emission anisotropies are also valuable for precision cross section ratio measurements, if the distributions are different for the two isotopes used in the ratio. Available angular data is sparse for {sup 235}U and even more so for {sup 239}Pu, especially at neutron energies above 5 MeV. The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) time projection chamber, which enables precise tracking of charged particles, can be used to study angular distributions and emission anisotropies of fission fragments in neutron-induced fission. In-beam data collected at the Los Alamos Neutron Science Center with a {sup 235}U/{sup 239}Pu target during the 2014 run-cycle will provide angular distributions as a function of incident neutron energy for these isotopes. (LA-UR-1426972). (authors)

  10. Advances on fission chamber modelling

    International Nuclear Information System (INIS)

    Filliatre, Philippe; Jammes, Christian; Geslot, Benoit; Veenhof, Rob

    2013-06-01

    In-vessel, online neutron flux measurements are routinely performed in mock-up and material testing reactors by fission chambers. Those measurements have a wide range of applications, including characterization of experimental conditions, reactor monitoring and safety. Depending on the application, detectors may experience a wide range of constraints, of several magnitudes, in term of neutron flux, gamma-ray flux, temperature. Hence, designing a specific fission chamber and measuring chain for a given application is a demanding task. It can be achieved by a combination of experimental feedback and simulating tools, the latter being based on a comprehensive understanding of the underlying physics. A computation route that simulates fission chambers, named CHESTER, is presented. The retrieved quantities of interest are the neutron-induced charge spectrum, the electronic and ionic pulses, the mean current and variance, the power spectrum. It relies on the GARFIELD suite, originally developed for drift chambers, and makes use of the MAGBOLTZ code to assess the drift parameters of electrons within the filling gas, and the SRIM code to evaluate the stopping range of fission products. The effect of the gamma flux is also estimated. Computations made with several fission chambers exemplify the possibilities of the route. A good qualitative agreement is obtained when comparing the results with the experimental data available to date. In a near future, a comprehensive experimental programme will be undertaken to qualify the route using the known neutron sources, mock-up reactors and wide choice of fission chambers, with a stress on the predictiveness of the Campbelling mode. Depending on the results, a refinement of the modelling and an effort on the accuracy of input data are also to be considered. CHESTER will then make it possible to predict the overall sensitivity of a chamber, and to optimize the design for a given application. Another benefit will be to increase the

  11. Contribution to the study of nuclear fission

    International Nuclear Information System (INIS)

    Serot, O.

    2009-09-01

    The author proposes an overview of his research activity during the past fifteen years and more particularly that dealing with nuclear fission. The first part reports works on nucleus physics at the scission via the investigation of ternary fission (experimental procedure, influence of fission modes, influence of resonance spin, influence of excitation energy of the fissioning nucleus, emission probabilities, energy spectra of ternary alphas and tritons, emission mechanism). The second part reports measurements and assessments of neutron-induced fission cross sections. The third part reports the investigation of some properties of fission products (efficiencies, branching ratios of the main delayed neutron precursors)

  12. Influence of tracks densities in solid state nuclear track detectors

    International Nuclear Information System (INIS)

    Guedes O, S.; Hadler N.; Lunes, P.; Saenz T, C.

    1996-01-01

    When Solid State Nuclear Track Detectors (SSNTD) is employed to measure nuclear tracks produced mainly by fission fragments and alpha particles, it is considered that the tracks observation work is performed under an efficiency, ε 0 , which is independent of the track density (number of tracks/area unit). There are not published results or experimental data supporting such an assumption. In this work the dependence of ε 0 with track density is studied basing on experimental data. To perform this, pieces of CR-39 cut from a sole 'mother sheet' were coupled to thin uranium films for different exposition times and the resulting ratios between track density and exposition time were compared. Our results indicate that ε 0 is constant for track densities between 10 3 and 10 5 cm -2 . At our etching conditions track overlapping makes impossible the counting for densities around 1.7 x 10 5 cm -2 . For track densities less than 10 3 cm -2 , ε 0 , was not observed to be constant. (authors). 4 refs., 2 figs

  13. Change over from compound nuclear fission to quasi-fission

    International Nuclear Information System (INIS)

    Ghosh, T. K.; Banerjee, K.; Bhattacharya, C.; Bhattacharya, S.; Kundu, S.; Meena, J. K.; Mukherjee, G.; Mukhopadhyay, S.; Rana, T. K.; Golda, K. S.; Bhattacharya, P.

    2010-01-01

    Fission fragment mass distribution has been measured from the decay of 246 Bk nucleus populating via two entrance channels with slight difference in mass asymmetries but belonging on either side of the Businaro Gallone mass asymmetry parameter. Both the target nuclei were deformed. Near the Coulomb barrier, at similar excitation energies the width of the fission fragment mass distribution was found to be drastically different for the 14 N+ 232 Th reaction compared to the 11 B+ 235 U reaction. The entrance channel mass asymmetry was found to affect the fusion process sharply. (authors)

  14. Change over from compound nuclear fission to quasi-fission

    Directory of Open Access Journals (Sweden)

    Bhattacharya P.

    2010-03-01

    Full Text Available Fission fragment mass distribution has been measured in two reactions to populate compound nucleus 246Bk. Both the target nuclei were deformed. However, entrance channel mass asymmetry of the two systems was on the either side of the Businaro Gallone mass asymmetry parameter. Near the Coulomb barrier, at similar excitation energies, the width of the fission fragment mass distribution was found to be significantly different for the 14N+232Th reaction compared to the 11B+235U reaction. The entrance channel mass asymmetry was found to play a significant role in deciding the fusion process.

  15. Nuclear fission and neutron-induced fission cross-sections

    CERN Document Server

    James, G D; Michaudon, A; Michaudon, A; Cierjacks, S W; Chrien, R E

    2013-01-01

    Nuclear Fission and Neutron-Induced Fission Cross-Sections is the first volume in a series on Neutron Physics and Nuclear Data in Science and Technology. This volume serves the purpose of providing a thorough description of the many facets of neutron physics in different fields of nuclear applications. This book also attempts to bridge the communication gap between experts involved in the experimental and theoretical studies of nuclear properties and those involved in the technological applications of nuclear data. This publication will be invaluable to those interested in studying nuclear fis

  16. Science and technology with nuclear tracks in solids

    CERN Document Server

    Buford-Price, P

    2005-01-01

    Fission track dating has greatly expanded its usefulness to geology over the last 40 years. It is central to thermochronology—the use of shortened fission tracks to decipher the thermal history, movement, and provenance of rocks. When combined with other indicators, such as zircon color and (U–Th)/He, a range of temperatures from C to C can be studied. Combining fission track analysis with cosmogenic nuclide decay rates, one can study landscape development and denudation of passive margins. Technological applications have expanded from biological filters, radon mapping, and dosimetry to the use of ion track microtechnology in microlithography, micromachining by ion track etching, microscopic field emission tips, magnetic nanowires as magnetoresistive sensors, microfluidic devices, physiology of ion channels in single cells, and so on. In nuclear and particle physics, relatively insensitive glass detectors have been almost single-handedly responsible for our knowledge of cluster radioactivity, and plastic ...

  17. Biomimetic nanocrystalline apatite coatings synthesized by Matrix Assisted Pulsed Laser Evaporation for medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Visan, A. [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania); Grossin, D. [CIRIMAT – Carnot Institute, University of Toulouse, ENSIACET, 4 Allée Emile Monso, 31030 Toulouse Cedex 4 (France); Stefan, N.; Duta, L.; Miroiu, F.M. [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania); Stan, G.E. [National Institute of Materials Physics, RO-077125, Magurele-Ilfov (Romania); Sopronyi, M.; Luculescu, C. [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania); Freche, M.; Marsan, O.; Charvilat, C. [CIRIMAT – Carnot Institute, University of Toulouse, ENSIACET, 4 Allée Emile Monso, 31030 Toulouse Cedex 4 (France); Ciuca, S. [Politehnica University of Bucharest, Faculty of Materials Science and Engineering, Bucharest (Romania); Mihailescu, I.N., E-mail: ion.mihailescu@inflpr.ro [National Institute for Lasers, Plasma, and Radiation Physics, 409 Atomistilor Street, RO-77125, MG-36, Magurele-Ilfov (Romania)

    2014-02-15

    Highlights: • We report the deposition by MAPLE of biomimetic apatite coatings on Ti substrates. • This is the first report of MAPLE deposition of hydrated biomimetic apatite films. • Biomimetic apatite powder was synthesized by double decomposition process. • Non-apatitic environments, of high surface reactivity, are preserved post-deposition. • We got the MAPLE complete transfer as thin film of a hydrated, delicate material. -- Abstract: We report the deposition by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique of biomimetic nanocrystalline apatite coatings on titanium substrates, with potential application in tissue engineering. The targets were prepared from metastable, nanometric, poorly crystalline apatite powders, analogous to mineral bone, synthesized through a biomimetic approach by double decomposition process. For the deposition of thin films, a KrF* excimer laser source was used (λ = 248 nm, τ{sub FWHM} ≤ 25 ns). The analyses revealed the existence, in synthesized powders, of labile non-apatitic mineral ions, associated with the formation of a hydrated layer at the surface of the nanocrystals. The thin film analyses showed that the structural and chemical nature of the nanocrystalline apatite was prevalently preserved. The perpetuation of the non-apatitic environments was also observed. The study indicated that MAPLE is a suitable technique for the congruent transfer of a delicate material, such as the biomimetic hydrated nanohydroxyapatite.

  18. Geochronology and geochemistry by nuclear tracks method: some utilization examples in geologic applied

    International Nuclear Information System (INIS)

    Poupeau, G.; Soliani Junior, E.

    1988-01-01

    This article discuss some applications of the 'nuclear tracks method' in geochronology, geochemistry and geophysic. In geochronology, after rapid presentation of the dating principles by 'Fission Track' and the kinds of geological events mensurable by this method, is showed some application in metallogeny and in petroleum geolocy. In geochemistry the 'fission tracks' method utilizations are related with mining prospecting and uranium prospecting. In geophysics an important application is the earthquake prevision, through the Ra 222 emanations continous control. (author) [pt

  19. New insight on the high radiation resistance of UO{sub 2} against fission fragments

    Energy Technology Data Exchange (ETDEWEB)

    Szenes, G., E-mail: szenesgyorgy@caesar.elte.hu

    2016-12-15

    Track radii are derived for semiconductors from a temperature distribution Θ(r) in which the width of the distribution is the only materials parameter. Analysis of track data for GeS, InP, GaAs and GaN show that the projectile velocity has no effect on track radii in semiconductors. Due to the missing velocity effect, the threshold for track formation, S{sub et} = 20 keV/nm is high in semiconducting UO{sub 2} in the whole range of projectile velocities. This is the origin of the high radiation resistance for fission fragments. Consequences for the simulation experiments with insulating CeO{sub 2} are discussed. It is verified that sputtering is described accurately by the Arrhenius equation for various materials including UO{sub 2}. The ion-induced surface potential has a strong effect on the activation energy. - Highlights: • Uniform features of track formation are demonstrated. • Semiconductors are more stable than insulators against fission fragments. • Melting point and width of the thermal spike control the track size. • High threshold for tracks S{sub et} = 20 keV/nm for fission fragments in semiconducting UO{sub 2}. • An Arrhenius equation describes the inelastic sputtering in UO{sub 2} and other solids.

  20. NEACRP thermal fission product benchmark

    International Nuclear Information System (INIS)

    Halsall, M.J.; Taubman, C.J.

    1989-09-01

    The objective of the thermal fission product benchmark was to compare the range of fission product data in use at the present time. A simple homogeneous problem was set with 200 atoms H/1 atom U235, to be burnt up to 1000 days and then decay for 1000 days. The problem was repeated with 200 atoms H/1 atom Pu239, 20 atoms H/1 atom U235 and 20 atoms H/1 atom Pu239. There were ten participants and the submissions received are detailed in this report. (author)

  1. Search for Singlet Fission Chromophores

    Energy Technology Data Exchange (ETDEWEB)

    Havlas, Z.; Akdag, A.; Smith, M. B.; Dron, P.; Johnson, J. C.; Nozik, A. J.; Michl, J.

    2012-01-01

    Singlet fission, in which a singlet excited chromophore shares its energy with a ground-state neighbor and both end up in their triplet states, is of potential interest for solar cells. Only a handful of compounds, mostly alternant hydrocarbons, are known to perform efficiently. In view of the large number of conditions that a successful candidate for a practical cell has to meet, it appears desirable to extend the present list of high performers to additional classes of compounds. We have (i) identified design rules for new singlet fission chromophores and for their coupling to covalent dimers, (ii) synthesized them, and (iii) evaluated their performance as neat solids or covalent dimers.

  2. Evaluation of apatite silicates as solid oxide fuel cell electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Marrero-Lopez, D. [Dpto. de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain); Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Martin-Sedeno, M.C.; Aranda, M.A.G. [Dpto. de Quimica Inorganica, Universidad Malaga, 29071 Malaga (Spain); Pena-Martinez, J. [Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Instituto de Energias Renovables, Parque Tecnologico, Universidad de Castilla La Mancha, 02006 Albacete (Spain); Ruiz-Morales, J.C.; Nunez, P. [Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Ramos-Barrado, J.R. [Dpto. de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain)

    2010-05-01

    Apatite-type silicates have been considered as promising electrolytes for Solid Oxide Fuel Cells (SOFC); however studies on the potential use of these materials in SOFC devices have received relatively little attention. The lanthanum silicate with composition La{sub 10}Si{sub 5.5}Al{sub 0.5}O{sub 26.75} has been evaluated as electrolyte with the electrode materials commonly used in SOFC, i.e. manganite, ferrite and cobaltite as cathode materials and NiO-CGO composite, chromium-manganite and Sr{sub 2}MgMoO{sub 6} as anode materials. Chemical compatibility, area-specific resistance and fuel cell studies have been performed. X-ray powder diffraction (XRPD) analysis did not reveal any trace of reaction products between the apatite electrolyte and most of the aforementioned electrode materials. However, the area-specific polarisation resistance (ASR) of these electrodes in contact with apatite electrolyte increased significantly with the sintering temperature, indicating reactivity at the electrolyte/electrode interface. On the other hand, the ASR values are significantly improved using a ceria buffer layer between the electrolyte and electrode materials to prevent reactivity. Maximum power densities of 195 and 65 mWcm{sup -2} were obtained at 850 and 700 C, respectively in H{sub 2} fuel, using an 1 mm-thick electrolyte, a NiO-Ce{sub 0.8}Gd{sub 0.2}O{sub 1.9} composite as anode and La{sub 0.6}Sr{sub 0.4}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} as cathode materials. This fuel cell was tested for 100 h in 5%H{sub 2}-Ar atmosphere showing stable performance. (author)

  3. Slab track

    OpenAIRE

    Golob, Tina

    2014-01-01

    The last 160 years has been mostly used conventional track with ballasted bed, sleepers and steel rail. Ensuring the high speed rail traffic, increasing railway track capacities, providing comfortable and safe ride as well as high reliability and availability railway track, has led to development of innovative systems for railway track. The so-called slab track was first built in 1972 and since then, they have developed many different slab track systems around the world. Slab track was also b...

  4. Developing biogeochemical tracers of apatite weathering by ectomycorrhizal fungi

    Science.gov (United States)

    Vadeboncoeur, M. A.; Bryce, J. G.; Hobbie, E. A.; Meana-Prado, M. F.; Blichert-Toft, J.

    2012-12-01

    Chronic acid deposition has depleted calcium (Ca) from many New England forest soils, and intensive harvesting may reduce phosphorus (P) available to future rotations. Thin glacial till soils contain trace amounts of apatite, a primary calcium phosphate mineral, which may be an important long-term source of both P and Ca to ecosystems. The extent to which ECM fungi enhance the weathering rate of primary minerals in soil which contain growth-limiting nutrients remains poorly quantified, in part due to biogeochemical tracers which are subsequently masked by within-plant fractionation. Rare earth elements (REEs) and Pb isotope ratios show some potential for revealing differences in soil apatite weathering rates across forest stands and silvicultural treatments. To test the utility of these tracers, we grew birch seedlings semi-hydroponically under controlled P-limited conditions, supplemented with mesh bags containing granite chips. Our experimental design included nonmycorrhizal (NM) as well as ectomycorrhizal cultures (Cortinarius or Leccinum). Resulting mycorrhizal roots and leachates of granite chips were analyzed for these tracers. REE concentrations in roots were greatly elevated in treatments with granite relative to those without granite, demonstrating uptake of apatite weathering products. Roots with different mycorrhizal fungi accumulated similar concentrations of REEs and were generally elevated compared to the NM cultures. Ammonium chloride leaches of granite chips grown in contact with mycorrhizal hyphae show elevated REE concentrations and significantly radiogenic Pb isotope signatures relative to bulk rock, also supporting enhanced apatite dissolution. Our results in culture are consistent with data from field-collected sporocarps from hardwood stands in the Bartlett Experimental Forest in New Hampshire, in which Cortinarius sporocarp Pb isotope ratios were more radiogenic than those of other ectomycorrhizal sporocarps. Taken together, the experimental

  5. H-Isotopic Composition of Apatite in Northwest Africa 7034

    Science.gov (United States)

    McCubbin, F. M.; Barnes, J. J.; Santos, A. R.; Boyce, J. W.; Anand, M.; Franchi, I. A.; Agee, C. B.

    2016-01-01

    Northwest Africa (NWA) 7034 and its pairings comprise a regolith breccia with a basaltic bulk composition [1] that yields a better match than any other martian meteorite to estimates of Mars' bulk crust composition [1]. Given the similarities between NWA 7034 and the martian crust, NWA 7034 may represent an important sample for constraining the crustal composition of components that cannot be measured directly by remote sensing. In the present study, we seek to constrain the H isotopic composition of the martian crust using Cl-rich apatite in NWA 7034.

  6. Collective spectra along the fission barrier

    OpenAIRE

    Pigni M. T.; Andreev A. V.; Shneidman T. M.; Massimi C.; Vannini G.; Ventura A.

    2012-01-01

    Discrete and continuous spectra of fissioning nuclei at the humps of fission barriers (Bohr transition states) and in the intermediate wells (superdeformed and hyperdeformed states) play a key role in the calculation of fission cross sections. A theoretical evaluation of the collective parts of the spectra is possible within the framework of the dinuclear system model, which treats the wave function of the fissioning nucleus as a superposition of a mononucleus configuration and two–cluster co...

  7. Investigation of exotic fission modes

    International Nuclear Information System (INIS)

    Poenaru, D. N.; Gherghescu, R. A.; Greiner, W.; Nagame, Y.; Hamilton, J. H.; Ramayya, A. V.

    2002-01-01

    Fission approach to the cluster radioactivities and α-decay has been systematically developed during the last two decades. A more complex process, the ternary fission, was observed since 1946 both in neutron-induced and spontaneous fission. We obtained interesting results concerning the binary fission saddle-point reflection asymmetric nuclear shapes, and we can explain how a possible nuclear quasimolecular state is formed during the 10 Be accompanied cold fission of 252 Cf. The equilibrium nuclear shapes in fission theory are usually determined by minimizing the deformation energy for a given surface equation. We developed a method allowing to obtain a very general saddle-point shape as a solution of a differential equation without an a priori introduction of a shape parametrization. In the approach based on a liquid drop model (LDM), saddle-point shapes are always reflection symmetric: the deformation energy increases with the mass-asymmetry parameter η = (A 1 - A 2 )/(A 1 + A 2 ). By adding the shell corrections to the LDM deformation energy, we obtained minima at a finite mass asymmetry for parent nuclei 238 U, 232,228 Th in agreement with experiments. This correction was calculated phenomenologically. A technique based on the fragment identification by using triple γ coincidences in the large arrays of Ge-detectors, like GAMMASPHERE, was employed at Vanderbilt University to discover new characteristics of the fission process, and new decay modes. The possibility of a whole family of new decay modes, the multicluster accompanied fission, was envisaged. Besides the fission into two or three fragments, a heavy or superheavy nucleus spontaneously breaks into four, five or six nuclei of which two are asymmetric or symmetric heavy fragments and the others are light clusters, e.g. α-particles, 10 Be, 14 C, or combinations of them. Examples were presented for the two-, three- and four cluster accompanied cold fission of 252 Cf and 262 Rf, in which the emitted

  8. Detection of fission fragments and alpha particles using the solid trace detector CR-39

    International Nuclear Information System (INIS)

    Santos, R.C.

    1988-01-01

    The technique of detecting charged particles using the solid track detector CR-39 is employed to establish some characteristics of fission fragments and alpha particles emitted from a Cf-252 source. Results are presented and discussed on the following aspects i) distribution of the track diameters; ii) variations on the track diameters to the chemical attack; iii) variations of the chemical attack velocity with respect to concentration and temperature. iv) activation energy of the developping process; v) induction time; vi) critical angle and efficiency on track developping. (A.C.A.S.) [pt

  9. Charged particle-induced nuclear fission reactions – Progress and ...

    Indian Academy of Sciences (India)

    progress made in recent years and the prospects in the area of nuclear fission research will be the focus of this review. Keywords. Nuclear fission; charged particle-induced fission; heavy ions; fission angular distribu- tions; mass distributions; fission barrier; moment of inertia; shell effect in fission. PACS Nos 25.70.Jj; 25.85.

  10. Measurement of fission anisotropy for Ta

    Indian Academy of Sciences (India)

    F on many actinide targets with large deformations exhibit dramatic increase with decreasing energy [5]. In order to understand the data, an admixture of non compound reaction processes, like the fast fission, the quasifission with orientation dependence and the preequilibrium fission, is introduced as a source of fission like ...

  11. Fission fragment mass and angular distributions

    Indian Academy of Sciences (India)

    2015-07-22

    Jul 22, 2015 ... Synthesis of heavy and superheavy elements is severely hindered by fission and fission-like processes. The probability of these fission-like, non-equilibrium processes strongly depends on the entrance channel parameters. This article attempts to summarize the recent experimental findings and classify the ...

  12. Fission yield data evaluation system FYDES

    International Nuclear Information System (INIS)

    Liu Tingjin

    1998-01-01

    Taking account of some features of fission yield data, to do the fission yield data evaluation conveniently, a fission yield data evaluation system FYDES has been developed for last two years. Outline of the system, data retrieval and data table standardization, data correction codes, data averaging code, simultaneous evaluation code and data fit programs were introduced

  13. Charged particle-induced nuclear fission reactions

    Indian Academy of Sciences (India)

    The nuclear fission phenomenon continues to be an enigma, even after nearly 75 years of its discovery. Considerable progress has been made towards understanding the fission process. Both light projectiles and heavy ions have been employed to investigate nuclear fission. An extensive database of the properties of ...

  14. Spontaneous fission of superheavy nuclei

    Indian Academy of Sciences (India)

    collaborators [1,2]. The importance of deformed valleys in the potential energy surfaces. (PES) is that they provide the most favoured fission channels for the decay of superheavy nuclei. For the dynamics study, one has to introduce the influence of mass tensor. We use the results from pairing calculations for the occupation ...

  15. Fission hindrance and nuclear viscosity

    Indian Academy of Sciences (India)

    of fission in terms of the ratio of transition states at the saddle point to the level density ... It was also intended to probe any turning over or reduction of γ .... 4. Summary and discussion. In this contribution we have reviewed our measurements which were carried out to inves- tigate the dependence of nuclear viscosity ...

  16. Spontaneous fission of superheavy nuclei

    Indian Academy of Sciences (India)

    2015-08-02

    Aug 2, 2015 ... The macroscopic–microscopic method is extended to calculate the deformation energy and penetrability for binary nuclear configurations typical for fission processes. The deformed two-centre shell model is used to obtain single-particle energy levels for the transition region of two partially overlapped ...

  17. Spontaneous fission of superheavy nuclei

    Indian Academy of Sciences (India)

    the Yukawa-plus-exponential potential. The microscopic shell and pairing corrections are obtained using the Strutinsky and BCS approaches and the cranking formulae yield the inertia tensor. Finally, the WKB method is used to calculate penetrabilities and spontaneous fission half-lives. Calculations are performed for the ...

  18. Spontaneous fission of superheavy nuclei

    Indian Academy of Sciences (India)

    2015-08-02

    Aug 2, 2015 ... ... nuclear configurations typical for fission processes. The deformed two-centre shell model is used to obtain single-particle energy levels for the transition region of two partially overlapped daughter and emitted fragment nuclei. The macroscopic part is obtained using the Yukawa-plus-exponential potential.

  19. Spin determination of fission resonances

    International Nuclear Information System (INIS)

    Keyworth, G.A.

    1976-01-01

    The present status of available information on the channel quantum numbers for resonance fission and the most urgently needed additional experiments are examined. The role of spin in the 235 U + n system is emphasized. The discussion relies heavily on recent alignment measurements and polarization results

  20. Fission approach to cluster radioactivity

    Indian Academy of Sciences (India)

    2015-08-04

    Aug 4, 2015 ... Also, the analytical superasymmetric fission (ASAF) model is successfully employed to make a systematic search and to predict, with other models, cluster ... those of the staff, the journals, various programmes, and Current Science, has changed from 'ias.ernet.in' (or 'academy.ias.ernet.in') to 'ias.ac.in'. Thus ...

  1. Nuclear fission with inertial confinement

    CERN Document Server

    Koshkarev, D G

    2002-01-01

    The possibility of initiating the explosive fission reaction in a small quantity of fissile material through the heavy ions beam from the powerful accelerator-driver, developed for realization of the thermonuclear synthesis in the deuterium-tritium cylindrical targets with the direct ignition, is considered. The consequences of applying this method in the nuclear engineering are discussed

  2. Atomistic simulation of track formation by energetic recoils in zircon.

    Science.gov (United States)

    Moreira, Pedro A F P; Devanathan, Ram; Weber, William J

    2010-10-06

    We have performed classical molecular dynamics simulations of fission track formation in zircon. We simulated the passage of a swift heavy ion through crystalline zircon using cylindrical thermal spikes with energy deposition (dE/dx) of 2.5-12.8 keV nm( - 1) and a radius of 3 nm. At a low dE/dx of 2.55 keV nm( - 1), the structural damage recovered almost completely and a damage track was not produced. At higher values of dE/dx, tracks were observed and the radius of the track increased with increasing dE/dx. Our structural analysis shows amorphization in the core of the track and phase separation into Si-rich regions near the center of the track and Zr-rich regions near the periphery. These simulations establish a threshold dE/dx for fission track formation in zircon that is relevant to thermochronology and nuclear waste immobilization.

  3. Genesis of iron-apatite ores in Posht-e-Badam Block (Central Iran ...

    Indian Academy of Sciences (India)

    A probable source for this large scale ore forming processes is relatively low partial melting of ... REE composition of the parent magma (Taylor .... Location of the iron-apatite deposits in the southern part of the Posht-e-Badam Block (Bafq region) on the satellite image. sandstones. Some iron-apatite ores of this block are.

  4. Mineralogical studies of apatites of Gara-aghaj deposit from mineral processing viewpoint

    International Nuclear Information System (INIS)

    Mehdilo, A.; Irannajad, M.

    2012-01-01

    Gara-aghaj deposit located 36 km northwest of urumieh is one of the titanium phosphorous resources in Iran. The previous exploration studies indicated that there is 102 Mt phosphorous ore deposit with average grading of 2.3 p ercent P 2 O 5 . In this research, the mineralogical studies of collected representative samples were performed by XRD, XRF, optical microscopy and SEM equipped by EDX. These studies indicated that ilmenite, magnetite and apatite are the main valuable minerals. The gangue minerals consist of the silicate minerals such as pyroxene, olivine, plagioclase and some secondary minerals. Analysis of apatite by EDX showed the presence of fluor-apatite in the ore. From textural viewpoint, apatites is mainly interlocked with ilmenite, magnetite and some gangue minerals with 60 microns liberation degree but there are some inclusions of apatite inside ilmenite and magnetite. The heavy liquid separation tests indicated that the first type of apatites, with density of 3, is mainly concentrated in tailing of gravity separation methods. This type of apatites is recoverable by flotation method. So, apatite concentrate can be obtained as a by-product of ilmenite concentration process by gravity methods.

  5. Heterotopic bone formation by nano-apatite containing poly (D,L-lactide) composites

    NARCIS (Netherlands)

    Barbieri, D.; Barbieri, D.; Renard, A.J.S.; de Bruijn, Joost Dick; Yuan, Huipin

    2010-01-01

    To render polymeric materials osteoinductive, nano-sized calcium phosphate apatite particles (CaP) were introduced into a low molecular weight poly(D,L-lactide). Homogenous composites were made with 10%, 20% and 40% by weight of apatite content while pure polylactide was used as control. Thereafter

  6. Genesis of iron-apatite ores in Posht-e-Badam Block (Central Iran ...

    Indian Academy of Sciences (India)

    Iran iron-apatite ores are clearly related to an extensional setting where rifting was important (SSE–NNW fault lines). A probable ... and McLennan 1985). Of crucial importance is the ..... at the Esfordi deposit, (c) the Zarigan phosphate deposit and (d) fine to coarse-grained euhedral apatite crystals within the magnetite at the ...

  7. Influence of local charge compensation on site occupation and luminescence of apatites

    NARCIS (Netherlands)

    Blasse, G.

    The apatite structure contains two different sites for the larger cations. It is shown that the principle of local charge compensation can predict the site occupation. This is especially important for an interpretation of the luminescence properties of a number of apatites. The predictions are

  8. Effect of apatite cements on human osteoblasts in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Yuasa, T.; Miyamoto, Y.; Takechi, M.; Momota, Y.; Toh, T.; Nagayama, M. [Tokushima Univ. (Japan). First Dept. of Oral and Maxillofacial Surgery; Ishikawa, K.; Suzuki, K. [Okayama Univ. Dental School (Japan). Dept. of Biomaterials

    2001-07-01

    A conventional apatite cement (c-AC) used for reconstruction of bony defect takes 30 min to set and decays upon exposure to liquid before setting. Therefore, we have developed two types of new ACs; fast-setting AC and anti-washout type AC. The aims of this study are to investigate the effect of ACs on cultured osteoblasts and to compare effects of new ACs on osteoblasts with that of c-AC. Disc shape set ACs with almost same surface roughness were prepared and evaluated by powder X-ray diffraction (XRD). The clonal human osteoblasts were cultured on each specimens. Plastic dish and sintered hydroxyapatite (HAP) were used as control. ACs showed the same apatitic XRD patterns with poor crystallinity when compared with sintered HAP. There were no differences in proliferation of osteoblasts among ACs and sintered HAP. The alkaline phosphatase activity and protein levels for type I collagen and osteocalcin of ACs were greater than those of sintered HAP. There was no difference among ACs. In conclusion, it is suggested that ACs could promote the differentiation of osteoblasts as compared with sintered HAP and plastic. Also, it is suggested that two types of new ACs would show the same cell response as c-AC in vivo (orig.)

  9. Increasing Diversity of Biological Membrane Fission Mechanisms.

    Science.gov (United States)

    Renard, Henri-François; Johannes, Ludger; Morsomme, Pierre

    2018-01-04

    Membrane fission is essential to life. It is required for many fundamental cellular processes, as diverse as cyto- and karyokinesis, organelle division, membrane repair, and membrane trafficking and endocytosis. While membrane fission was originally seen as resulting from the action of mechanoenzymes such as dynamin, it is clear that the reality is more complex. In this review, we propose an updated overview of fission mechanisms, and try to extract essential requirements for each. We also present examples of cellular processes that involve these fission mechanisms. Finally, we list pending questions, whether they are specific to a peculiar fission mechanism or more general to the field. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Heavy-ion induced fission reactions

    International Nuclear Information System (INIS)

    Britt, H.C.; Fowler, M.M.; Fraenkel, Z.; Gavron, A.; Plicht, J.; Wilhelmy, J.B.; Plasil, F.; Awes, T.; Young, G.

    1983-01-01

    Heavy-ion induced fission reactions are investigated. The problem of obtaining a representative set of fission-cross section data, so that it would be possible to test both the mass and angular momentum dependence of fission barriers in the mass region 150 9 Be through 64 Ni. The experimental data clearly show the qualitative effects of angular momentum, excitation energy and fissility on the fission cross section. They provide an ideal testing ground for theoretical models of fission in this mass region

  11. Fission-track evidence of tectonic evolution in the northwestern ...

    Indian Academy of Sciences (India)

    Guo-Qiang Sun

    2018-02-14

    Feb 14, 2018 ... The right panels are the age component and. Gaussian curve histograms. Cretaceous (102–85 Ma), the Kohistan Ladakh block in the northwestern Indian Plate collided with the Eurasian Plate (Jin 1999); subsequently, at 92–89 Ma, the deep part of the Altyn Tagh region commenced ductile strike-slip ...

  12. Fission-track evidence of tectonic evolution in the northwestern ...

    Indian Academy of Sciences (India)

    8

    right Y-axis, which indicates the age of that grain. The right panels are the age component and. Gaussian curve histograms. Figure 4. Evolution of the Altyn Tagh strike-slip fault (modified after Liu et al. 2001) a.At the end of the Mesozoic era, the Tibetan plateau started to uplift alone with the collision between the Indian and ...

  13. Methodological study of volcanic glass dating by fission track method

    International Nuclear Information System (INIS)

    Araya, A.M.O.

    1987-01-01

    After a description of the method and from the analysis of the age equation we show the methodology used in the plotting of the correction curve and the results of the study of correction curves and corrected ages. From a study of the size correction method we see that the reactor irradiation effect on the curve is negligible and that the correction curve is independent of the thermal treatment but, it depends on chemical treatment and sample. Comparing the corrected ages obtained from both correction method and the ages given by other authors we can conclude that they are in agreement and concerning the plateau method, both isothermal and isochronic plateau give the same results. (author) [pt

  14. Tooth apatite as a bone substitute: an experimental study and clinical applications

    International Nuclear Information System (INIS)

    Eun-Seok Kim; Pill-Hoon Choung

    1999-01-01

    The purpose of this study is to evaluate the usefulness of calcined teeth powder as biological apatite. The animal experiment was performed in 36 rabbits aging 6 weeks and weighing 1.6 kg. In experimental group, tooth apatite powder was implanted to 10 mm bony defects in diameter made on the cranial bone of the rabbits. As control groups, synthetic porous hydroxyapatite and resorbable type calcium carbonate were implanted to the defects of same size. Each group was sacrificed in 1, 2, 4, 6, 8, 12 weeks after the surgery. Specimens were prepared for decalcified samples and observed by a light microscope. And we also performed quantitative analysis of new bone formation through image analysis using computer. In clinical applications, we used tooth apatite alone or mixed with decalcified freeze-dried bone for reconstruction of bony defects in 15 patients undergone enucleation of cyst or ameloblastoma. The obtained results were as follows; 1) The powder of the calcined teeth was called as 'tooth apatite' and it seemed to have biocompatibility in rabbits and human. 2) In group of tooth apatite, after 4 weeks of operation, new bone directly bonded to the particles was observed. And in 12 weeks of it, new bone occupied most of the bony defects. In 6 weeks, resorption of the tooth apatite particles was observed. Thus the tooth apatite was regarded as one of resorbable apatite. 3) The group of tooth apatite showed new bone formation similar to the group of porous hydroxyapatite, but they were inferior to the group of resorbable calcium carbonate. 4) In clinical application, tooth apatite had biocompatibility and new bone formation was observed without any complication except for 1 case. So we think it is a useful bone substitute with osteoconductivity

  15. Endogenous Lunar Volatiles: Insights into the Abundances of Volatiles in the Moon from Lunar Apatite

    Science.gov (United States)

    McCubbin, Francis

    2016-01-01

    At the time of publication of New Views of the Moon, it was thought that the Moon was bone dry with less than about 1 ppb H2O. However in 2007, initial reports at the 38th Lunar and Planetary Science Conference speculated that H-species were present in both apatites and pyroclastic volcanic lunar glasses. These early reports were later confirmed through peer-review, which motivated many subsequent studies on magmatic volatiles in and on the Moon within the last decade. Some of these studies have cast into question the post-Apollo view of lunar formation, the distribution and sources of volatiles in the Earth-Moon system, and the thermal and magmatic evolution of the Moon. The mineral apatite has been one of the pillars of this new field of study, and it will be the primary focus of this abstract. Although apatite has been used both to understand the abundances of volatiles in lunar systems as well as the isotopic compositions of those volatiles, the focus here will be on the abundances of F, Cl, and H2O. This work demonstrates the utility of apatite in advancing our understanding of lunar volatiles, hence apatite should be among the topics covered in the endogenous lunar volatile chapter in NVM II. Truncated ternary plot of apatite X-site occupancy (mol%) from highlands apatite and mare basalt apatite plotted on the relative volatile abundance diagram from. The solid black lines delineate fields of relative abundances of F, Cl, and H2O (on a weight basis) in the melt from which the apatite crystallized. The diagram was constructed using available apatite/melt partitioning data for fluorine, chlorine, and hydroxyl.

  16. Fission dynamics in the proton induced fission of heavy nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Rubchenya, V.A. E-mail: rubchen@phys.jyu.fi; Trzaska, W.H.; Itkis, I.M.; Itkis, M.G.; Kliman, J.; Kniajeva, G.N.; Kondratiev, N.A.; Kozulin, E.M.; Krupa, L.; Pokrovski, I.V.; Voskressenski, V.M.; Hanappe, F.; Materna, T.; Dorvaux, O.; Stuttge, L.; Chubarian, G.; Khlebnikov, S.V.; Vakhtin, D.N.; Lyapin, V.G

    2004-04-05

    Multi-parameter correlation study of the reaction {sup 242}Pu(p, f) at E{sub p} 13, 20 and 55 MeV has been carried out. Fission fragment mass and kinetic energy distributions and the double differential neutron spectra have been measured. It was observed that the two-humped shape of mass distributions prevailed up to highest proton energy. Manifestation of the nuclear shell Z 28 near fragment mass A{sub fr} = 70 has been detected. The experimental results were analyzed in the framework of a time-dependent statistical model with inclusion of nuclear friction effects in the fission process. The multi-parameter correlation study of the reaction.

  17. A fission fragment detector for correlated fission output studies

    Energy Technology Data Exchange (ETDEWEB)

    Mosby, S., E-mail: smosby@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Tovesson, F.; Couture, A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Duke, D.L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Colorado School of Mines, Golden, CO 80401 (United States); Kleinrath, V. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Idaho State University, Pocatello, ID 83201 (United States); Meharchand, R.; Meierbachtol, K.; O' Donnell, J.M.; Perdue, B.; Richman, D. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Shields, D. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Colorado School of Mines, Golden, CO 80401 (United States)

    2014-09-01

    A digital data acquisition system has been combined with a double Frisch gridded ionization chamber for use at both moderated and unmoderated neutron sources at the Los Alamos Neutron Science (LANSCE) facility. The high efficiency of the instrument combined with intense LANSCE beams and new acquisition system permits fission output measurements across 11 orders of magnitude incident neutron energy. The acquisition and analysis system is presented along with the first in-beam performance tests of the setup.

  18. Material synergism fusion-fission

    International Nuclear Information System (INIS)

    Sankara Rao, K.B.; Raj, B.; Cook, I.; Kohyama, A.; Dudarev, S.

    2007-01-01

    In fission and fusion reactors the common features such as operating temperatures and neutron exposures will have the greatest impact on materials performance and component lifetimes. Developing fast neutron irradiation resisting materials is a common issue for both fission and fusion reactors. The high neutron flux levels in both these systems lead to unique materials problems like void swelling, irradiation creep and helium embitterment. Both fission and fusion rely on ferritic-martensitic steels based on 9%Cr compositions for achieving the highest swelling resistance but their creep strength sharply decreases above ∝ 823K. The use of oxide dispersion strengthened (ODS) alloys is envisaged to increase the operating temperature of blanket systems in the fusion reactors and fuel clad tubes in fast breeder reactors. In view of high operating temperatures, cyclic and steady load conditions and the long service life, properties like creep, low cycle fatigue,fracture toughness and creepfatigue interaction are major considerations in the selection of structural materials and design of components for fission and fusion reactors. Currently, materials selection for fusion systems has to be based upon incomplete experimental database on mechanical properties. The usage of fairly well developed databases, in fission programmes on similar materials, is of great help in the initial design of fusion reactor components. Significant opportunities exist for sharing information on technology of irradiation testing, specimen miniaturization, advanced methods of property measurement, safe windows for metal forming, and development of common materials property data base system. Both fusion and fission programs are being directed to development of clean steels with very low trace and tramp elements, characterization of microstructure and phase stability under irradiation, assessment of irradiation creep and swelling behaviour, studies on compatibility with helium and developing

  19. Delayed Fission Gamma-ray Characteristics of Th-232 U-233 U-235 U-238 and Pu-239

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Taylor [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Parma, Edward J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    Delayed fission gamma-rays play an important role in determining the time dependent ioniz- ing dose for experiments in the central irradiation cavity of the Annular Core Research Reactor (ACRR). Delayed gamma-rays are produced from both fission product decay and from acti- vation of materials in the core, such as cladding and support structures. Knowing both the delayed gamma-ray emission rate and the time-dependent gamma-ray energy spectrum is nec- essary in order to properly determine the dose contributions from delayed fission gamma-rays. This information is especially important when attempting to deconvolute the time-dependent neutron, prompt gamma-ray, and delayed gamma-ray contribution to the response of a diamond photo-conducting diode (PCD) or fission chamber in time frames of milliseconds to seconds following a reactor pulse. This work focused on investigating delayed gamma-ray character- istics produced from fission products from thermal, fast, and high energy fission of Th-232, U-233, U-235, U-238, and Pu-239. This work uses a modified version of CINDER2008, a transmutation code developed at Los Alamos National Laboratory, to model time and energy dependent photon characteristics due to fission. This modified code adds the capability to track photon-induced transmutations, photo-fission, and the subsequent radiation caused by fission products due to photo-fission. The data is compared against previous work done with SNL- modified CINDER2008 [ 1 ] and experimental data [ 2 , 3 ] and other published literature, includ- ing ENDF/B-VII.1 [ 4 ]. The ability to produce a high-fidelity (7,428 group) energy-dependent photon fluence at various times post-fission can improve the delayed photon characterization for radiation effects tests at research reactors, as well as other applications.

  20. Biomimetic magnesium–carbonate-apatite nanocrystals endowed with strontium ions as anti-osteoporotic trigger

    Energy Technology Data Exchange (ETDEWEB)

    Iafisco, Michele, E-mail: michele.iafisco@istec.cnr.it; Ruffini, Andrea; Adamiano, Alessio; Sprio, Simone; Tampieri, Anna

    2014-02-01

    The present work investigates the preparation of biomimetic nanocrystalline apatites co-substituted with Mg, CO{sub 3} and Sr to be used as starting materials for the development of nanostructured bio-devices for regeneration of osteoporotic bone. Biological-like amounts of Mg and CO{sub 3} ions were inserted in the apatite structure to mimic the composition of bone apatite, whereas the addition of increasing quantities of Sr ions, from 0 up to 12 wt.%, as anti-osteoporotic agent, was evaluated. The chemical–physical features, the morphology, the degradation rates, the ion release kinetics as well as the in vitro bioactivity of the as-prepared apatites were fully evaluated. The results indicated that the incorporation of 12 wt.% of Sr can be viewed as a threshold for the structural stability of Mg–CO{sub 3}-apatite. Indeed, incorporation of lower quantity of Sr did not induce considerable variations in the chemical structure of Mg–CO{sub 3}-apatite, while when the Sr doping extent reached 12 wt.%, a dramatically destabilizing effect was detected on the crystal structure thus yielding alteration of the symmetry and distortion of the PO{sub 4}. As a consequence, this apatite exhibited the fastest degradation kinetic and the highest amount of Sr ions released when tested in physiological conditions. In this respect, the surface crystallization of new calcium phosphate phase when immersed in physiological-like solution occurred by different mechanisms and extents due to the different structural chemistry of the variously doped apatites. Nevertheless, all the apatites synthesized in this work exhibited in vitro bioactivity demonstrating their potential use to develop biomedical devices with anti-osteoporotic functionality. - Highlights: • Biomimetic nanocrystalline apatites co-substituted with Mg, CO{sub 3} and Sr were prepared. • Biological-like amounts of Mg and CO{sub 3} were inserted to mimic the composition of bone apatite. • The addition of increasing

  1. Biomimetic magnesium–carbonate-apatite nanocrystals endowed with strontium ions as anti-osteoporotic trigger

    International Nuclear Information System (INIS)

    Iafisco, Michele; Ruffini, Andrea; Adamiano, Alessio; Sprio, Simone; Tampieri, Anna

    2014-01-01

    The present work investigates the preparation of biomimetic nanocrystalline apatites co-substituted with Mg, CO 3 and Sr to be used as starting materials for the development of nanostructured bio-devices for regeneration of osteoporotic bone. Biological-like amounts of Mg and CO 3 ions were inserted in the apatite structure to mimic the composition of bone apatite, whereas the addition of increasing quantities of Sr ions, from 0 up to 12 wt.%, as anti-osteoporotic agent, was evaluated. The chemical–physical features, the morphology, the degradation rates, the ion release kinetics as well as the in vitro bioactivity of the as-prepared apatites were fully evaluated. The results indicated that the incorporation of 12 wt.% of Sr can be viewed as a threshold for the structural stability of Mg–CO 3 -apatite. Indeed, incorporation of lower quantity of Sr did not induce considerable variations in the chemical structure of Mg–CO 3 -apatite, while when the Sr doping extent reached 12 wt.%, a dramatically destabilizing effect was detected on the crystal structure thus yielding alteration of the symmetry and distortion of the PO 4 . As a consequence, this apatite exhibited the fastest degradation kinetic and the highest amount of Sr ions released when tested in physiological conditions. In this respect, the surface crystallization of new calcium phosphate phase when immersed in physiological-like solution occurred by different mechanisms and extents due to the different structural chemistry of the variously doped apatites. Nevertheless, all the apatites synthesized in this work exhibited in vitro bioactivity demonstrating their potential use to develop biomedical devices with anti-osteoporotic functionality. - Highlights: • Biomimetic nanocrystalline apatites co-substituted with Mg, CO 3 and Sr were prepared. • Biological-like amounts of Mg and CO 3 were inserted to mimic the composition of bone apatite. • The addition of increasing quantities of Sr (from 0 to 12

  2. Nuclear Dissipation from Fission Time

    International Nuclear Information System (INIS)

    Gontchar, I.; Morjean, M.; Basnary, S.

    2000-01-01

    Fission times, pre-scission neutron multiplicities and GDR pre-scission γ-ray multiplicities measured for uranium or thorium nuclei formed with temperatures T ∼ 1.8 MeV have been compared with calculations performed with CDSM2, a two-dimensional dynamical model combined with a statistical one. Among the three experimental approaches considered, fission times give access to the most precise pieces of information on nuclear dissipation at high excitation energy. For the temperature range under consideration, an agreement between the model and data is achieved if one-body dissipation is used with a strength factor k red ∼ 0.45 ± 0.10 applied to the wall term for the mononuclear configuration. (authors)

  3. Sexual differentiation in fission yeast

    DEFF Research Database (Denmark)

    Egel, R; Nielsen, O; Weilguny, D

    1990-01-01

    The regulation of sexual reproduction in yeast constitutes the highest level of differentiation observed in these unicellular organisms. The various ramifications of this system involve DNA rearrangement, transcriptional control, post-translational modification (such as protein phosphorylation......) and receptor/signal processing. A few basic similarities are common to both fission and budding yeasts. The wiring of the regulatory circuitry, however, varies considerably between these divergent yeast groups....

  4. Recycling of used fission material

    International Nuclear Information System (INIS)

    Abrahams, K.

    1991-01-01

    One of the most important social obstructions for the final disposal of nuclear waste is the long lifetime of some radioactive nuclides. However there are new possibilities for recycling high-level radioactive wastes. By nuclear transformation the troublesome components in the waste, the actinides and the long-living fission products can be transformed into products with a shorter decay time. (author). 9 refs.; 2 figs.; 3 tabs

  5. The VERDI fission fragment spectrometer

    International Nuclear Information System (INIS)

    Fregeau, M. O.; Brys, T.; Gamboni, T.; Geerts, W.; Oberstedt, S.; Oberstedt, A.; Borcea, R.

    2013-01-01

    The VERDI time-of-flight spectrometer is dedicated to measurements of fission product yields and of prompt neutron emission data. Pre-neutron fission-fragment masses will be determined by the double time-of-flight (TOF) technique. For this purpose an excellent time resolution is required. The time of flight of the fragments will be measured by electrostatic mirrors located near the target and the time signal coming from silicon detectors located at 50 cm on both sides of the target. This configuration, where the stop detector will provide us simultaneously with the kinetic energy of the fragment and timing information, significantly limits energy straggling in comparison to legacy experimental setup where a thin foil was usually used as a stop detector. In order to improve timing resolution, neutron transmutation doped silicon will be used. The high resistivity homogeneity of this material should significantly improve resolution in comparison to standard silicon detectors. Post-neutron fission fragment masses are obtained form the time-of-flight and the energy signal in the silicon detector. As an intermediary step a diamond detector will also be used as start detector located very close to the target. Previous tests have shown that poly-crystalline chemical vapour deposition (pCVD) diamonds provides a coincidence time resolution of 150 ps not allowing complete separation between very low-energy fission fragments, alpha particles and noise. New results from using artificial single-crystal diamonds (sCVD) show similar time resolution as from pCVD diamonds but also sufficiently good energy resolution. (authors)

  6. Status update on the NIFFTE high precision fission cross section measurement program

    International Nuclear Information System (INIS)

    Laptev, Alexander B.; Tovesson, Fredrik; Burgett, Eric; Greife, Uwe; Grimes, Steven; Heffner, Michael D.; Hertel, Nolan E.; Hill, Tony; Isenhower, Donald; Klay, Jennifer L.; Kornilov, Nickolay; Kudo, Ryuho; Loveland, Walter; Massey, Thomas; McGrath, Chris; Pickle, Nathan; Qu, Hai; Sharma, Sarvagya; Snyder, Lucas; Thornton, Tyler; Towell, Rusty S.; Watson, Shon

    2010-01-01

    The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) program has been underway for nearly two years. The program's mission is to measure fission cross sections of the primary fissionable and fissile materials ( 235 U, 239 Pu, 238 U) as well as the minor actinides across energies from approximately 50 keV up to 20 MeV with an absolute uncertainty of less than one percent while investigating energy ranges from below an eV to 600 MeV. This basic nuclear physics data is being reinvestigated to support the next generation power plants and a fast burner reactor program. Uncertainties in the fast, resolved and unresolved resonance regions in plutonium and other transuranics are extremely large, dominating safety margins in the next generation nuclear power plants and power plants of today. This basic nuclear data can be used to support all aspects of the nuciear renaissance. The measurement campaign is utilizing a Time Projection Chamber or TPC as the tool to measure these cross sections to these unprecedented levels. Unlike traditional fission cross section measurements using time-of-flight and a multiple fission foil configurations in which fission cross sections in relation to that of 235 U are performed, the TPC project uses time-of-flight and hydrogen as the benchmark cross section. Using the switch to hydrogen, a simple, smooth cross section that can be used which removes the uncertainties associated with the resolved and unresolved resonances in 235 U.

  7. Comparative sequence analysis of primate subtelomeres originating from a chromosome fission event

    Science.gov (United States)

    Rudd, M. Katharine; Endicott, RaeLynn M.; Friedman, Cynthia; Walker, Megan; Young, Janet M.; Osoegawa, Kazutoyo; de Jong, Pieter J.; Green, Eric D.; Trask, Barbara J.

    2009-01-01

    Subtelomeres are concentrations of interchromosomal segmental duplications capped by telomeric repeats at the ends of chromosomes. The nature of the segments shared by different sets of human subtelomeres reflects their high rate of recent interchromosomal exchange. Here, we characterize the rearrangements incurred by the 15q subtelomere after it arose from a chromosome fission event in the common ancestor of great apes. We used FISH, sequencing of genomic clones, and PCR to map the breakpoint of this fission and track the fate of flanking sequence in human, chimpanzee, gorilla, orangutan, and macaque genomes. The ancestral locus, a cluster of olfactory receptor (OR) genes, lies internally on macaque chromosome 7. Sequence originating from this fission site is split between the terminus of 15q and the pericentromere of 14q in the great apes. Numerous structural rearrangements, including interstitial deletions and transfers of material to or from other subtelomeres, occurred subsequent to the fission, such that each species has a unique 15q structure and unique collection of ORs derived from the fission locus. The most striking rearrangement involved transfer of at least 200 kb from the fission-site region to the end of chromosome 4q, where much still resides in chimpanzee and gorilla, but not in human. This gross structural difference places the subtelomeric defect underlying facioscapulohumeral muscular dystrophy (FSHD) much closer to the telomere in human 4q than in the hybrid 4q–15q subtelomere of chimpanzee. PMID:18952852

  8. Status update on the NIFFTE high precision fission cross section measurement program

    Energy Technology Data Exchange (ETDEWEB)

    Laptev, Alexander B [Los Alamos National Laboratory; Tovesson, Fredrik [Los Alamos National Laboratory; Burgett, Eric [GEORGIA INSTITUTE OF TECH; Greife, Uwe [COLORADO SCHOOL OF THE MINES; Grimes, Steven [OHIO UNIV; Heffner, Michael D [LLNL; Hertel, Nolan E [GEORGIA INSTITUTE OF TECH; Hill, Tony [IDAHO NATIONAL LABORATORY; Isenhower, Donald [ABILENE CHRISTIN UNIV; Klay, Jennifer L [CALIFORNIA POLYTECHNIC STATE UNIV; Kornilov, Nickolay [OHIO UNIV; Kudo, Ryuho [CALIFORNIA POLYTECHNIC STATE UNIV; Loveland, Walter [OREGON STATE UNIV; Massey, Thomas [OHIO UNIV; Mc Grath, Chris [IDAHO NATIONAL LABORATORY; Pickle, Nathan [ABILENE CHRISTIAN UNIV; Qu, Hai [ABILENE CHRISTIAN UNIV; Sharma, Sarvagya [ABILENE CHRISTIAN UNIV; Snyder, Lucas [COLORADO SCHOOL OF THE MINES; Thornton, Tyler [ABILENE CHRISTIAN UNIV; Towell, Rusty S [ABILENE CHRISTIAN UNIV; Watson, Shon [ABILENE CHRISTIAN UNIV

    2010-01-01

    The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) program has been underway for nearly two years. The program's mission is to measure fission cross sections of the primary fissionable and fissile materials ({sup 235}U, {sup 239}Pu, {sup 238}U) as well as the minor actinides across energies from approximately 50 keV up to 20 MeV with an absolute uncertainty of less than one percent while investigating energy ranges from below an eV to 600 MeV. This basic nuclear physics data is being reinvestigated to support the next generation power plants and a fast burner reactor program. Uncertainties in the fast, resolved and unresolved resonance regions in plutonium and other transuranics are extremely large, dominating safety margins in the next generation nuclear power plants and power plants of today. This basic nuclear data can be used to support all aspects of the nuciear renaissance. The measurement campaign is utilizing a Time Projection Chamber or TPC as the tool to measure these cross sections to these unprecedented levels. Unlike traditional fission cross section measurements using time-of-flight and a multiple fission foil configurations in which fission cross sections in relation to that of {sup 235}U are performed, the TPC project uses time-of-flight and hydrogen as the benchmark cross section. Using the switch to hydrogen, a simple, smooth cross section that can be used which removes the uncertainties associated with the resolved and unresolved resonances in {sup 235}U.

  9. Radionuclide Incorporation and Long Term Performance of Apatite Waste Forms

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jianwei [Louisiana State Univ., Baton Rouge, LA (United States); Lian, Jie [Rensselaer Polytechnic Inst., Troy, NY (United States); Gao, Fei [Univ. of Michigan, Ann Arbor, MI (United States)

    2016-01-04

    This project aims to combines state-of-the-art experimental and characterization techniques with atomistic simulations based on density functional theory (DFT) and molecular dynamics (MD) simulations. With an initial focus on long-lived I-129 and other radionuclides such as Cs, Sr in apatite structure, specific research objectives include the atomic scale understanding of: (1) incorporation behavior of the radionuclides and their effects on the crystal chemistry and phase stability; (2) stability and microstructure evolution of designed waste forms under coupled temperature and radiation environments; (3) incorporation and migration energetics of radionuclides and release behaviors as probed by DFT and molecular dynamics (MD) simulations; and (4) chemical durability as measured in dissolution experiments for long term performance evaluation and model validation.

  10. Magnetic apatite for structural insights on the plasma membrane.

    Science.gov (United States)

    Stanca, Sarmiza E; Müller, Robert; Dellith, Jan; Nietzsche, Sandor; Stöckel, Stephan; Biskup, Christoph; Deckert, Volker; Krafft, Christoph; Popp, Jürgen; Fritzsche, Wolfgang

    2015-01-21

    The iron oxide-hydroxyapatite (FeOxHA) nanoparticles reported here differ from those reported before by their advantage of homogeneity and simple preparation; moreover, the presence of carboxymethyldextran (CMD), together with hydroxyapatite (HA), allows access to the cellular membrane, which makes our magnetic apatite unique. These nanoparticles combine magnetic behavior, Raman label ability and the property of interaction with the cellular membrane; they therefore represent an interesting material for structural differentiation of the cell membrane. It was observed by Raman spectroscopy, scanning electron microscopy (SEM) and fluorescence microscopy that FeOxHA adheres to the plasma membrane and does not penetrate the membrane. These insights make the nanoparticles a promising material for magnetic cell sorting, e.g. in microfluidic device applications.

  11. Morphology and annealing kinetics of ion tracks in minerals

    Directory of Open Access Journals (Sweden)

    Ewing R. C.

    2012-10-01

    Full Text Available We have studied the morphology and annealing kinetics of ion tracks in Durango apatite using synchrotron small angle X-ray scattering. The non-destructive, artefact-free technique enables us to determine the track radii with a resolution of fractions of a nanometre. The tracks were generated using different heavy ions with energies between 185 MeV and 2.6 GeV. The track morphology is consistent with the formation of long cylindrical amorphous tracks. The annealing kinetics, measured by SAXS in combination with ex situ and in situ annealing experiments, suggests structural relaxation followed by recrystallisation of the damaged material. The measurement methodology shown here provides a new means for in-depth studies of ion-track formation in minerals under a wide variety of geological conditions.

  12. Mineralogical and geochemical studies on apatites and phosphate host rocks of Esfordi deposit, Yazd province, to determine the origin and geological setting of the apatite

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Rajabzadeh

    2014-10-01

    Full Text Available Introduction Iron-apatite ore deposits well known as Kiruna iron type formed in association with calc-alkaline volcanism from Proterozoic to Tertiary (Hitzman et al., 1992. Liquid immiscibility in an igneous system was proposed to explain the formation of the iron oxides accompanying apatite in mineralized zones (Förster and Jafarzadeh, 1994; Daliran, 1999. The mode of ore formation however, is a matter in debate. Bafq region in Central Iran is one of the greatest iron mining regions in Iran with 750 million tons of reservoir. The majority of the iron deposits contains apatite as minor mineral and underwent metamorphism-alteration in varying degrees. The mode of formation and geological setting of Esfordi iron-apatite deposit in this region with an average of 13.9 wt% apatite are discussed using geochemical and mineralogical data along with field description. Materials and methods Fifty-three samples of mineralized zones and host rocks collected from 7 cross sections were studied by conventional microscopic methods. Seven representative samples were determined by XRD at Department of Physics, Shiraz University. Fifteen and six samples were also analyzed for major and trace elements using XRF at Binaloud Co. Iran, and ICP-MS at Labwest Minerals Analysis, Australia, respectively. Microprobe analyses were carried out on apatite in Geo Forschungs Zentrum Telegrafenberg at Potsdam University, Germany. Results Field observation shows that igneous host rocks in Esfordi were intensively altered by hydrothermal fluids. The ores are surrounded by wide altered halos. Petrographic investigation indicated that the most important alterations are of potassic, carbonatitic and silicification types. Magnetite and apatite occur as major minerals, accompanied by minor hematite and goethite in the mineralized zones. Rare Earth Element (REE minerals are present as minor phases in the ores. Three apatite mineralization types (vein, massive, and disseminated were

  13. High phosphate content significantly increases apatite formation of fluoride-containing bioactive glasses.

    Science.gov (United States)

    Mneimne, Mohammed; Hill, Robert G; Bushby, Andrew J; Brauer, Delia S

    2011-04-01

    Bioactive glass-containing toothpastes for treating dentine hypersensitivity work by precipitating hydroxycarbonate apatite (HCA) onto the tooth surface, but concerns exist over the long-term durability of HCA in the mouth. Fluoride-containing bioactive glasses form fluorapatite (FAp) in physiological solutions, which is more chemically stable against acid attack. The influence of phosphate content on apatite formation was investigated by producing a low-phosphate (about 1 mol% P(2)O(5)) and a high-phosphate (about 6 mol%) series of melt-derived bioactive glasses in the system SiO(2)P(2)O(5)CaONa(2)O; increasing amounts of CaF(2) were added by keeping the ratio of all other components constant. pH change, ion release and apatite formation during immersion in Tris buffer at 37°C over up to 7 days were investigated. Crystal phases formed in Tris buffer were characterized using infrared spectroscopy, X-ray diffraction and solid-state nuclear magnetic resonance (NMR) spectroscopy. An increase in phosphate or fluoride content allowed for apatite formation at lower pH; fluoride enhanced apatite formation due to lower solubility of FAp compared to hydroxyapatite or HCA. High phosphate content glasses formed apatite significantly faster (within 6h) than low phosphate content glasses (within 3 days). In addition, an increase in phosphate content favoured apatite formation rather than fluorite (CaF(2)). (19)F magic angle spinning NMR showed the apatite formed by fluoride-containing glasses to be FAp, which makes these glasses of particular interest for dental applications. This study shows that by varying the phosphate content, the reactivity and apatite formation of bioactive glasses can be controlled successfully. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  14. Fusion-Fission Hybrid for Fissile Fuel Production without Processing

    Energy Technology Data Exchange (ETDEWEB)

    Fratoni, M; Moir, R W; Kramer, K J; Latkowski, J F; Meier, W R; Powers, J J

    2012-01-02

    Two scenarios are typically envisioned for thorium fuel cycles: 'open' cycles based on irradiation of {sup 232}Th and fission of {sup 233}U in situ without reprocessing or 'closed' cycles based on irradiation of {sup 232}Th followed by reprocessing, and recycling of {sup 233}U either in situ or in critical fission reactors. This study evaluates a third option based on the possibility of breeding fissile material in a fusion-fission hybrid reactor and burning the same fuel in a critical reactor without any reprocessing or reconditioning. This fuel cycle requires the hybrid and the critical reactor to use the same fuel form. TRISO particles embedded in carbon pebbles were selected as the preferred form of fuel and an inertial laser fusion system featuring a subcritical blanket was combined with critical pebble bed reactors, either gas-cooled or liquid-salt-cooled. The hybrid reactor was modeled based on the earlier, hybrid version of the LLNL Laser Inertial Fusion Energy (LIFE1) system, whereas the critical reactors were modeled according to the Pebble Bed Modular Reactor (PBMR) and the Pebble Bed Advanced High Temperature Reactor (PB-AHTR) design. An extensive neutronic analysis was carried out for both the hybrid and the fission reactors in order to track the fuel composition at each stage of the fuel cycle and ultimately determine the plant support ratio, which has been defined as the ratio between the thermal power generated in fission reactors and the fusion power required to breed the fissile fuel burnt in these fission reactors. It was found that the maximum attainable plant support ratio for a thorium fuel cycle that employs neither enrichment nor reprocessing is about 2. This requires tuning the neutron energy towards high energy for breeding and towards thermal energy for burning. A high fuel loading in the pebbles allows a faster spectrum in the hybrid blanket; mixing dummy carbon pebbles with fuel pebbles enables a softer spectrum in

  15. Correction of Thick Foil Errors in Prompt Neutron (CALIFORNIUM-252 Nu), Fission Cross Section (sigma(f)) and Other Ionization Chamber Fission Data Standards.

    Science.gov (United States)

    Cohensedgh, Farhad

    This research resolves two problems that have long been of important concern in experimental fission physics: (1) determination of pulse height distribution response of ionization chambers in fission fragment detection measurements, and (2) correction of "thick-foil effect" systematic errors in standard values of the fundamental parameters of fission physics--the average number of prompt neutrons per fission (=nu), absolute fission activity and true fission rate of samples (TFR), and isotopic fission cross sections (sigma _{f}). Results are obtained by a comprehensive digital simulation of the electrostatics and pulse height distribution response of the parallel-plate, ungridded, electron-pulse ionization fission chamber together with prompt neutron -fragment multiplicity and angular distribution correlations, neutron-fragment coincidence detection and related variations in the 4pi^here around the chamber for a wide range of the relevant factors--foil thickness, alpha particle interference bias level, fission detector configuration characteristics, fissile isotopes (^{252}Cf, ^{235}U, etc.) and other experimental parameters. Isotope-specific double-energy (E_1,E_2) natural variations in fragment spectrum, in fragment-specific range-energy (dE/dx) relations and in prompt neutron-fragment multiplicity (nu) and nuclear temperature dependent angular distribution correlations are simulated in detail. Detailed results are obtained for double-energy, fragment-specific count loss fractions resulting from in -foil fragment absorption and from alpha -interference discrimination as well as for chamber detection efficiency, fragment spectrum distortion and prompt neutron -fragment coincidence detection distribution variations. Decay alpha pulse pileup statistics are discussed, and the behavior of and factors affecting the fragment pulse height distribution tail are analyzed in detail. Fragment pairs and prompt neutrons issued from them are tracked in the 4pi^ace around the

  16. The resonance neutron fission on heavy nuclei

    CERN Document Server

    Kopach, Yu N; Furman, V I; Alfimenkov, V P; Lason', L; Pikelner, L B; Gonin, N N; Kozlovskij, L K; Tambovtsev, D I; Gagarskij, A M; Petrov, G A; Sokolov, V E

    2001-01-01

    A new approach to the description of the fission, similar to the well-known reaction theory and based on the helicity representation for the exit fission channels, is briefly summarized. This approach allows one to connect the multimodal fission representation with A. Bohr's concept of the fission transition states and to obtain formulae for the partial and differential fission cross sections. The formulae are used for analysis of the angular anisotropy of fragments in the neutron resonance induced fission of aligned sup 2 sup 3 sup 5 U nuclei and of the P-even angular forward-backward and right-left correlations of fragments oe the P-odd correlations caused by the interference of s- and p-wave neutron resonances

  17. Collective spectra along the fission barrier

    Directory of Open Access Journals (Sweden)

    Pigni M. T.

    2012-12-01

    Full Text Available Discrete and continuous spectra of fissioning nuclei at the humps of fission barriers (Bohr transition states and in the intermediate wells (superdeformed and hyperdeformed states play a key role in the calculation of fission cross sections. A theoretical evaluation of the collective parts of the spectra is possible within the framework of the dinuclear system model, which treats the wave function of the fissioning nucleus as a superposition of a mononucleus configuration and two–cluster configurations in a dynamical way, permitting exchange of upper–shell nucleons between clusters. The impact of theoretical spectra on neutron–induced fission cross sections and, in combination with an improved version of the scission–point model, on angular distribution of fission fragments is evaluated for plutonium isotopes of interest to nuclear energy applications.

  18. Collective spectra along the fission barrier

    Science.gov (United States)

    Shneidman, T. M.; Andreev, A. V.; Pigni, M. T.; Massimi, C.; Vannini, G.; Ventura, A.

    2012-12-01

    Discrete and continuous spectra of fissioning nuclei at the humps of fission barriers (Bohr transition states) and in the intermediate wells (superdeformed and hyperdeformed states) play a key role in the calculation of fission cross sections. A theoretical evaluation of the collective parts of the spectra is possible within the framework of the dinuclear system model, which treats the wave function of the fissioning nucleus as a superposition of a mononucleus configuration and two-cluster configurations in a dynamical way, permitting exchange of upper-shell nucleons between clusters. The impact of theoretical spectra on neutron-induced fission cross sections and, in combination with an improved version of the scission-point model, on angular distribution of fission fragments is evaluated for plutonium isotopes of interest to nuclear energy applications.

  19. The resonance neutron fission on heavy nuclei

    International Nuclear Information System (INIS)

    Kopach, Yu.N.; Popov, A.B.; Furman, V.I.; Alfimenkov, V.P.; Lason', L.; Pikel'ner, L.B.; ); Gonin, N.N.; Kozlovskij, L.K.; Tambovtsev, D.I.; Gagarskij, A.M.; Petrov, G.A.; Sokolov, V.E.

    2001-01-01

    A new approach to the description of the fission, similar to the well-known reaction theory and based on the helicity representation for the exit fission channels, is briefly summarized. This approach allows one to connect the multimodal fission representation with A. Bohr's concept of the fission transition states and to obtain formulae for the partial and differential fission cross sections. The formulae are used for analysis of the angular anisotropy of fragments in the neutron resonance induced fission of aligned 235 U nuclei and of the P-even angular forward-backward and right-left correlations of fragments oe the P-odd correlations caused by the interference of s- and p-wave neutron resonances [ru

  20. International conference on fifty years research in nuclear fission

    International Nuclear Information System (INIS)

    1989-02-01

    These proceedings contain extended abstracts of the papers presented at the named conference. They deal with static properties of fission, instrumentation for fission studies, fission in compound-nucleus reactions, fission dynamics, fission-like heavy ion reactions, and fusion reactions. See hints under the relevant topics. (HSI)

  1. Comparative evaluation of solar, fission, fusion, and fossil energy resources. Part 2: Power from nuclear fission

    Science.gov (United States)

    Clement, J. D.

    1973-01-01

    Different types of nuclear fission reactors and fissionable materials are compared. Special emphasis is placed upon the environmental impact of such reactors. Graphs and charts comparing reactor facilities in the U. S. are presented.

  2. Fission of nuclei far from stability

    International Nuclear Information System (INIS)

    Schmidt, K.H.; Benlliure, J.; Junghans, A.R.

    2000-11-01

    The secondary-beam facility of GSI provided the technical equipment for a new kind of fission experiment. Fission properties of short-lived neutron-deficient nuclei have been investigated in inverse kinematics. The measured element distributions reveal new kinds of systematics on shell structure and even-odd effects and lead to an improved understanding of structure effects in nuclear fission. Prospects for further experimental studies are discussed. (orig.)

  3. Monte carlo sampling of fission multiplicity.

    Energy Technology Data Exchange (ETDEWEB)

    Hendricks, J. S. (John S.)

    2004-01-01

    Two new methods have been developed for fission multiplicity modeling in Monte Carlo calculations. The traditional method of sampling neutron multiplicity from fission is to sample the number of neutrons above or below the average. For example, if there are 2.7 neutrons per fission, three would be chosen 70% of the time and two would be chosen 30% of the time. For many applications, particularly {sup 3}He coincidence counting, a better estimate of the true number of neutrons per fission is required. Generally, this number is estimated by sampling a Gaussian distribution about the average. However, because the tail of the Gaussian distribution is negative and negative neutrons cannot be produced, a slight positive bias can be found in the average value. For criticality calculations, the result of rejecting the negative neutrons is an increase in k{sub eff} of 0.1% in some cases. For spontaneous fission, where the average number of neutrons emitted from fission is low, the error also can be unacceptably large. If the Gaussian width approaches the average number of fissions, 10% too many fission neutrons are produced by not treating the negative Gaussian tail adequately. The first method to treat the Gaussian tail is to determine a correction offset, which then is subtracted from all sampled values of the number of neutrons produced. This offset depends on the average value for any given fission at any energy and must be computed efficiently at each fission from the non-integrable error function. The second method is to determine a corrected zero point so that all neutrons sampled between zero and the corrected zero point are killed to compensate for the negative Gaussian tail bias. Again, the zero point must be computed efficiently at each fission. Both methods give excellent results with a negligible computing time penalty. It is now possible to include the full effects of fission multiplicity without the negative Gaussian tail bias.

  4. Measurements of Fission Cross Sections of Actinides

    CERN Multimedia

    Wiescher, M; Cox, J; Dahlfors, M

    2002-01-01

    A measurement of the neutron induced fission cross sections of $^{237}$Np, $^{241},{243}$Am and of $^{245}$Cm is proposed for the n_TOF neutron beam. Two sets of fission detectors will be used: one based on PPAC counters and another based on a fast ionization chamber (FIC). A total of 5x10$^{18}$ protons are requested for the entire fission measurement campaign.

  5. Status of fission product yield data

    International Nuclear Information System (INIS)

    Cuninghame, J.G.

    1978-01-01

    The topics covered in this paper are: (a) cumulative yields in thermal neutron fission and in fast fission up to 14 MeV incident neutron energy, (b) dependence of the yields on incident neutron energy and spectrum, (c) independent yields, (d) charge dispersion and distribution, and (e) yields of light particles from ternary fission. The paper reviews information on these subjects for fission of actinides from 232 Th upwards with special emphasis on data published since the 1973 Bologna FPND Panel, compares data sets, and discusses the gaps still to be found in them. (author)

  6. Theoretical Description of the Fission Process

    Energy Technology Data Exchange (ETDEWEB)

    Witold Nazarewicz

    2003-07-01

    The main goals of the project can be summarized as follows: Development of effective energy functionals that are appropriate for the description of heavy nuclei. Our goal is to improve the existing energy density (Skyrme) functionals to develop a force that will be used in calculations of fission dynamics. Systematic self-consistent calculations of binding energies and fission barriers of actinide and trans-actinide nuclei using modern density functionals. This will be followed by calculations of spontaneous fission lifetimes and mass and charge divisions using dynamic adiabatic approaches based on the WKB approximation. Investigate novel microscopic (non-adiabatic) methods to study the fission process.

  7. Attachment of gaseous fission products to aerosols

    International Nuclear Information System (INIS)

    Skyrme, G.

    1985-01-01

    Accidents may occur in which the integrity of fuel cladding is breached and volatile fission products are released to the containment atmosphere. In order to assess the magnitude of the subsequent radiological hazard it is necessary to know the transport behaviour of such fission products. It is frequently assumed that the fission products remain in the gaseous phase. There is a possibility, however, that they may attach themselves to particles and hence substantially modify their transport properties. This paper provides a theoretical assessment of the conditions under which gaseous fission products may be attached to aerosol particles. Specific topics discussed are: the mass transfer of a gaseous fission product to an isolated aerosol particle in an infinite medium; the rate at which the concentration of fission products in the gas phase diminishes within a container as a result of deposition on a population of particles; and the distribution of deposited fission product between different particle sizes in a log-normal distribution. It is shown that, for a given mass, small particles are more efficient for fission product attachment, and that only small concentrations of such particles may be necessary to achieve rapid attachment. Conditions under which gaseous fission products are not attached to particles are also considered, viz, the competing processes of deposition onto the containment walls and onto aerosol particles, and the possibility of the removal of aerosols from the containment by various deposition processes, or agglomeration, before attachment takes place. (author)

  8. True ternary fission in 310126X

    International Nuclear Information System (INIS)

    Banupriya, B.; Vijayaraghavan, K.R.; Balasubramaniam, M.

    2015-01-01

    All possible combinations are minimized by the two dimensional minimization process and minimized with respect to neutron numbers and proton numbers of the fragments. Potential energy is low and Q - value is high at true ternary fission region. It shows that true ternary mode is the dominant mode in the ternary fission of superheavy nuclei. Also, the results show that the fragments with neutron magic numbers are the dominant one in the ternary fission of superheavy nuclei whereas the fragments with proton magic numbers are the dominant one in the ternary fission of heavy nuclei

  9. Nuclear fission studies: from LOHENGRIN to FIPPS

    International Nuclear Information System (INIS)

    Chebboubi, Abdelaziz

    2015-01-01

    Nuclear fission consists in splitting a nucleus, in general an actinide, into smaller nuclei. Despite nuclear fission was discovered in 1939 by Hahn and Strassman, fission models cannot predict the fission observables with an acceptable accuracy for nuclear fuel cycle studies for instance. Improvement of fission models is an important issue for the knowledge of the process itself and for the applications. To reduce uncertainties of the nuclear data used in a nuclear reactor simulation, a validation of the models hypothesis is mandatory. In this work, two features of the nuclear fission were investigated in order to test the resistance of the theories. One aspect is the study of the symmetric fission fragments through the measurement of their yield and kinetic energy distribution. The other aspect is the study of the fission fragment angular momentum.Two techniques are available to assess the angular momentum of a fission fragment. The first one is to look at the properties of the prompt gamma. The new spectrometer FIPPS (Fission Product Prompt gamma-ray Spectrometer), is currently under development at the ILL and will combine a fission filter with a large array of gamma and neutron detectors in order to respond to these issues. The first part of this work is dedicated to the study of the properties of a Gas Filled Magnet (GFM) which is the type of fission filter considered for the FIPPS project.The second part of this work deals with the measurement of isomeric yields and evaluations of the angular momentum distribution of fission fragments. The study of the spherical nucleus 132 Sn shed the light on the current limits of fission models. Finally, the last part of this work is about the measurement of the yields and kinetic energy distributions of symmetric fission fragments. Since models predict the existence of fission modes, the symmetry region is a suitable choice to investigate this kind of prediction. In parallel with all these studies, an emphasis on the

  10. Theoretical Description of the Fission Process

    International Nuclear Information System (INIS)

    Witold Nazarewicz

    2003-01-01

    The main goals of the project can be summarized as follows: Development of effective energy functionals that are appropriate for the description of heavy nuclei. Our goal is to improve the existing energy density (Skyrme) functionals to develop a force that will be used in calculations of fission dynamics. Systematic self-consistent calculations of binding energies and fission barriers of actinide and trans-actinide nuclei using modern density functionals. This will be followed by calculations of spontaneous fission lifetimes and mass and charge divisions using dynamic adiabatic approaches based on the WKB approximation. Investigate novel microscopic (non-adiabatic) methods to study the fission process

  11. RMSRo

    DEFF Research Database (Denmark)

    Nielsen, S.B.; Clausen, O.R.; McGregor, Eoin David

    2014-01-01

    with the temperature-apatite fission track system. Keywords: vitrinite reflectance, basin analysis, thermal history, hydrocarbon exploration, apatite fission tracks Suggate, R.P., 1998. Relations between depth of burial, vitrinite reflectance and geothermal gradient. Jour- nal of Petroleum Geology, v. 21(1), January......Geophysical Research Abstracts Vol. 16, EGU2014-12484, 2014 EGU General Assembly 2014 © Author(s) 2014. CC Attribution 3.0 License. RMSRo: A vitrinite reflectance model consistent with the temperature-apatite fission track system Søren B. Nielsen, Ole R. Clausen, and Eoin D. McGregor Department...

  12. Surface Enamel Remineralization: Biomimetic Apatite Nanocrystals and Fluoride Ions Different Effects

    Directory of Open Access Journals (Sweden)

    Norberto Roveri

    2009-01-01

    Full Text Available A new method for altered enamel surface remineralization has been proposed. To this aim carbonate-hydroxyapatite nanocrystals which mimic for composition, structure, nanodimensions, and morphology dentine apatite crystals and resemble closely natural apatite chemical-physical properties have been used. The results underline the differences induced by the use of fluoride ions and hydroxyapatite nanocrystals in contrasting the mechanical abrasions and acid attacks to which tooth enamel is exposed. Fluoride ions generate a surface modification of the natural enamel apatite crystals increasing their crystallinity degree and relative mechanical and acid resistance. On the other hand, the remineralization produced by carbonate-hydroxyapatite consists in a deposition of a new apatitic mineral into the eroded enamel surface scratches. A new biomimetic mineral coating, which progressively fills and shadows surface scratches, covers and safeguards the enamel structure by contrasting the acid and bacteria attacks.

  13. Improvement of RVNRL film properties by adding fumed silica and hydroxy apatite

    Directory of Open Access Journals (Sweden)

    Adul Thiangchanya

    2003-01-01

    Full Text Available The effect of adding fumed silica and hydroxy apatite to Radiation Vulcanized Natural Rubber Latex (RVNRL for improving tear strength, aging properties, degradability and water-soluble protein content of rubber films has been investigated. The addition of fumed silica and hydroxy apatite in RVNRL improves tear strength and aging properties of rubber films, whereas tensile strength and degradability of rubber films were unchanged during storage at room temperature. The water-soluble protein content in rubber films was reduced by immobilization of the fumed silica and hydroxy apatite and enhanced by addition of ZnO. This may reduce allergy problems of natural rubber latex products caused by water-soluble protein. The MST of the RVNRL with fumed silica and hydroxy apatite indicated that the latex must be used within two months after mixing because of its stability.

  14. Geochemistry of Apatite in Climactic and Pre-Climactic Tephra from Mt. Mazama, Crater Lake, Oregon

    Science.gov (United States)

    Mandeville, C. W.; Langstaff, M.

    2007-12-01

    Apatite is a common accessory mineral in arc volcanic rocks that potentially records information about the dissolved volatile (S,Cl,F,OH) and trace-element concentrations (Sr, Ba, REEs) of the melt from which it crystallized. In a previous study of apatite from arc and convergent margin volcanic rocks, Peng et al. (1997) reported 0.63 wt.% SO3 in Mazama apatite grains with a corresponding SrO content of 0.18 wt.%, comprising some of the highest SO3 and SrO values in their data. Our electron microprobe study of apatite in climactic and pre-climactic Mazama tephra was done in order to assess possible correlation of apatite SO3 with Sr content of low-Sr and high-Sr recharge magmas identified based on whole-rock and matrix glass data (Bacon and Druitt, 1988) and Sr content of plagioclase (Druitt and Bacon 1989). Samples chosen represent all magmatic components erupted during the ca. 7700 year before present climactic eruption and precursor Llao Rock and Cleetwood eruptions. We compare the S, Cl, and F content of Mazama apatites with recent experimental data for S, Cl, and F partitioning between apatite and melt and with dissolved volatiles previously measured in melt inclusions from corresponding or similar Mazama samples. Our electron microprobe data confirm the presence of rare Mazama apatites with up to 0.78 wt.% SO3 and 0.12 wt.% SrO in Llao Rock, Cleetwood, and climactic scoria and pumice samples. However, high SO3 and SrO apatites are not restricted to high-Sr scoria hosts, but have been observed in low-Sr scoria, in Llao Rock rhyodacitic pumices and in Cleetwood rhyodacitic pumices, thus indicating significant magma mixing prior to the Llao Rock, Cleetwood and climactic eruptions. Most apatite SO3 and SrO data falls within the 0.06 to 0.36 wt.% and 0.04 to 0.12 wt.% range, respectively. Experimental data on SO3 partitioning between apatite and melt and maximum sulfur contents of 300 to 350 ppm measured in climactic and Cleetwood rhyodacitic melt inclusions

  15. CR-39 as induced track detector in reactor: irradiation effect

    International Nuclear Information System (INIS)

    Zylberberg, H.

    1989-07-01

    A systematic study about reactor's neutrons radiation effect and gamma radiation effect on the properties of CR-39 that are significant for its use as induced fission track detector is showed. The following studies deserved attention: kinetics of the fission track chemical development; efficiency to register and to develop fission track; losses of developable tracks; variation in the number of developable tracks and variation in the visible and ultraviolet radiation spectrum. The dissertation is organized in seven specific chapters: solid state nuclear tracks (SSNT); CR-39 as SSNT; objectives and problems presentation; preparation and characterization of CR-39 as SSNT; gamma irradiation effect on the properties of CR-39 as SSNT; reactor neutron irradiation effect on the properties of CR-39 as SSNT and, results discussions and conclusions. The main work contributions are the use of CR-39 in the determination of fissionable nuclide as thorium and uranium in solid and liquid samples; gamma radiation damage on CR-39 as well as the reactor's neutron damage on CR-39. (B.C.A.) 62 refs, 53 figs, 21 tabs

  16. Site-specific equilibrium isotopic fractionation of oxygen, carbon and calcium in apatite

    Science.gov (United States)

    Aufort, Julie; Ségalen, Loïc; Gervais, Christel; Paulatto, Lorenzo; Blanchard, Marc; Balan, Etienne

    2017-12-01

    The stable isotope composition of biogenic apatite is an important geochemical marker that can record environmental parameters and is widely used to infer past climates, biomineralization processes, dietary preferences and habitat of vertebrates. In this study, theoretical equilibrium isotopic fractionation of oxygen, carbon and calcium in hydroxyapatite and carbonate-bearing hydroxyapatite is investigated using first-principles methods based on density-functional theory and compared to the theoretical isotopic fractionation properties of calcite, CO2 and H2O. Considering the variability of apatite crystal-chemistry, special attention is given to specific contributions of crystal sites to isotopic fractionation. Significant internal fractionation is calculated for oxygen and carbon isotopes in CO3 between the different structural sites occupied by carbonate groups in apatite (typically 7‰ for both 18O/16O and 13C/12C fractionation at 37 °C). Compared with calcite-water oxygen isotope fractionation, occurrence of A-type substitution in apatite structure, in addition to the main B-type substitution, could explain the larger temperature dependence of oxygen isotope fractionation measured at low temperature between carbonate in apatite and water. Theoretical internal fractionation of oxygen isotopes between carbonate and phosphate in B-type carbonated apatite (∼8‰ at 37 °C) is consistent with experimental values obtained from modern and well-preserved fossil bio-apatites. Concerning calcium, theoretical results suggest a small fractionation between apatite and calcite (-0.17‰ at 37 °C). Internal fractionation reaching 0.8‰ at 37 °C occurs between the two Ca sites in hydroxyapatite. Furthermore, the Ca isotopic fractionation properties of apatite are affected by the occurrence of carbonate groups, which could contribute to the variability observed on natural samples. Owing to the complexity of apatite crystal-chemistry and in light of the theoretical

  17. Apatite formation on non-woven fabric of carboxymethylated chitin in SBF.

    Science.gov (United States)

    Kokubo, Tadashi; Hanakawa, Masayuki; Kawashita, Masakazu; Minoda, Masahiko; Beppu, Toshiyuki; Miyamoto, Takeaki; Nakamura, Takashi

    2004-08-01

    Chitin fibres constituting a non-woven fabric were carboxymethylated in monochloro acetic acid and treated with saturated Ca(OH)(2) aqueous solution. Within 3 days in a simulated body fluid with pH value and ion concentrations nearly equal to those of human blood plasma, a bonelike apatite layer formed on the surface of fibres of the treated fabric. The apatite-chitin fibre composite thus prepared is expected to be useful as a flexible bioactive bone-repairing material.

  18. Fluoride enhances transfection activity of carbonate apatite by increasing cytoplasmic stability of plasmid DNA

    International Nuclear Information System (INIS)

    Chowdhury, E.H.

    2011-01-01

    Highlights: → Cytoplasmic stability of plasmid DNA is enhanced by fluoride incorporation into carbonate apatite carrier. → Fluoridated carbonate apatite promotes a robust increase in transgene expression. → Controlled dissolution of fluoridated carbonate apatite in endosomal acidic environment might buffer the endosomes and prevent degradation of the released DNA. -- Abstract: Intracellular delivery of a functional gene or a nucleic acid sequence to specifically knockdown a harmful gene is a potential approach to precisely treat a critical human disease. The intensive efforts in the last few decades led to the development of a number of viral and non-viral synthetic vectors. However, an ideal delivery tool in terms of the safety and efficacy has yet to be established. Recently, we have developed pH-sensing inorganic nanocrystals of carbonate apatite for efficient and cell-targeted delivery of gene and gene-silencing RNA. Here we show that addition of very low level of fluoride to the particle-forming medium facilitates a robust increase in transgene expression following post-incubation of the particles with HeLa cells. Confocal microscopic observation and Southern blotting prove the cytoplasmic existence of plasmid DNA delivered by likely formed fluoridated carbonate apatite particles while degradation of plasmid DNA presumably by cytoplasmic nucleases was noticed following delivery with apatite particles alone. The beneficial role of fluoride in enhancing carbonate apatite-mediated gene expression might be due to the buffering potential of generated fluoridated apatite in endosomal acidic environment, thereby increasing the half-life of delivered plasmid DNA.

  19. Fluoride enhances transfection activity of carbonate apatite by increasing cytoplasmic stability of plasmid DNA

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, E.H., E-mail: md.ezharul.hoque@med.monash.edu.my [Jeffrey Cheah School of Medicine and Health Sciences, Monash University Sunway Campus, Jalan Lagoon Selatan, Bandar Sunway, Selangor Darul Ehsan (Malaysia)

    2011-06-17

    Highlights: {yields} Cytoplasmic stability of plasmid DNA is enhanced by fluoride incorporation into carbonate apatite carrier. {yields} Fluoridated carbonate apatite promotes a robust increase in transgene expression. {yields} Controlled dissolution of fluoridated carbonate apatite in endosomal acidic environment might buffer the endosomes and prevent degradation of the released DNA. -- Abstract: Intracellular delivery of a functional gene or a nucleic acid sequence to specifically knockdown a harmful gene is a potential approach to precisely treat a critical human disease. The intensive efforts in the last few decades led to the development of a number of viral and non-viral synthetic vectors. However, an ideal delivery tool in terms of the safety and efficacy has yet to be established. Recently, we have developed pH-sensing inorganic nanocrystals of carbonate apatite for efficient and cell-targeted delivery of gene and gene-silencing RNA. Here we show that addition of very low level of fluoride to the particle-forming medium facilitates a robust increase in transgene expression following post-incubation of the particles with HeLa cells. Confocal microscopic observation and Southern blotting prove the cytoplasmic existence of plasmid DNA delivered by likely formed fluoridated carbonate apatite particles while degradation of plasmid DNA presumably by cytoplasmic nucleases was noticed following delivery with apatite particles alone. The beneficial role of fluoride in enhancing carbonate apatite-mediated gene expression might be due to the buffering potential of generated fluoridated apatite in endosomal acidic environment, thereby increasing the half-life of delivered plasmid DNA.

  20. Revisiting carbonate quantification in apatite (bio)minerals: a validated FTIR methodology

    OpenAIRE

    Grunenwald, Anne; Keyser, Christine; Sautereau, Anne-Marie; Crubézy, Eric; Ludes, Bertrand; Drouet, Christophe

    2014-01-01

    International audience; Carbonated apatites represent an important class of compounds encountered in many fields including anthropology, archeology, geology, medicine and biomaterials engineering. They constitute, in particular, the mineral part of bones and teeth, are found in sedimentary settings, and are used as biomimetic compounds for the development of bone tissue engineering scaffolds. Whether for assessing the degree of biomimetism of synthetic apatites or for better understanding dia...

  1. Simulating fission product transients via the history-based local-parameter methodology

    International Nuclear Information System (INIS)

    Jenkins, D.A.; Rouben, B.; Salvatore, M.

    1993-01-01

    This paper describes the fission-product-calculation capacity of the history-based local-parameter methodology for evaluating lattice properties for use in core-tracking calculations in CANDU reactors. In addition to taking into account the individual past history of each bundles flux/power level, fuel temperature, and coolant density and temperature that the bundle has seen during its stay in the core, the latest refinement of the history-based method provides the capability of fission-product-drivers. It allows the bundle-specific concentrations of the three basic groups of saturating fission products to be calculated in steady state or following a power transient, including long shutdowns. The new capability is illustrated by simulating the startup period following a typical long-shutdown, starting from a snapshot in the Point Lepreau operating history. 9 refs., 7 tabs

  2. Measurement of {sup 238}Np fission cross-section by neutrons near thermal point (preliminary results)

    Energy Technology Data Exchange (ETDEWEB)

    Abramo; vich, S.N.; Andreev, M.F.; Bol`shakov, Y.M. [Institute of Experimental Physics, Arzamas (Russian Federation)] [and others

    1995-10-01

    Measurements have been carried out of {sup 238}Np fission cross-section by thermal neutrons. The isotope {sup 238}Np was built up through the reaction {sup 238}U(p,n) on an electrostatic accelerator. Extraction and cleaning of the sample were done by ion-exchange chromatography. Fast neutrons were generated on the electrostatic accelerator through the reaction {sup 9}Be(d,n); a polyethylene block was used to slow down neutrons. Registration of fission fragments was performed with dielectric track detectors. Suggesting that the behavior of {sup 238}Np and {sup 238}U. Westscott`s factors are indentical the fission cross-section of {sup 238}Np was obtained: {sigma}{sub fo}=2110 {plus_minus} 75 barn.

  3. Apatite deposition on titanium surfaces--the role of albumin adsorption.

    Science.gov (United States)

    Serro, A P; Fernandes, A C; Saramago, B; Lima, J; Barbosa, M A

    1997-07-01

    Titanium implant surfaces are known to spontaneously nucleate apatite layers when in contact with simulated body fluids. However, adsorption of proteins may influence the process of apatite layer formation. In this study the role of bovine serum albumin (BSA) adsorption in the process of apatite deposition on titanium substrates is investigated. Deposition of calcium phosphate was induced by immersing titanium substrates in a Hank's balanced salt solution (HBSS) for times ranging from 1 to 23 days. The resulting substrates were studied by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), wettability measurements and electrochemical impedance determinations. All these methods indicate the presence of a calcium phosphate layer. The same procedure was repeated substituting HBSS with a solution of BSA in HBSS. Although SEM, EDS and electrochemical impedance spectra do not reveal the presence of an apatite layer, XPS analysis strongly indicates that the inhibition of apatite formation by BSA is only partial. The competition between BSA adsorption and apatite deposition seems to lead to a mixed film where the protein co-exists with calcium phosphate. Wettability studies suggest that this surface film is heterogeneous and porous, similar to the thicker films formed in albumin-free HBSS.

  4. Nuclear Power from Fission Reactors. An Introduction.

    Science.gov (United States)

    Department of Energy, Washington, DC. Technical Information Center.

    The purpose of this booklet is to provide a basic understanding of nuclear fission energy and different fission reaction concepts. Topics discussed are: energy use and production, current uses of fuels, oil and gas consumption, alternative energy sources, fossil fuel plants, nuclear plants, boiling water and pressurized water reactors, the light…

  5. Progress in fission product nuclear data

    International Nuclear Information System (INIS)

    Lammer, M.

    1982-07-01

    This is the eighth issue of a report series on Fission Product Nuclear Data (FPND) which is published by the Nuclear Data Section (NDS) of the International Atomic Energy Agency (IAEA). The purpose of this series is to inform scientists working on FPND, or using such data, about all activities in this field which are planned, ongoing, or have recently been completed. The main part of this report consists of unaltered original contributions which the authors have sent to IAEA/NDS. Therefore, the IAEA cannot be held responsible for the information contained nor for any consequences resulting from the use of this information. The present issue contains also a section with some recent references relative to fission product nuclear data, which were not covered by the contributions submitted. The types of activities being included in this report are measurements, compilations and evaluations of: Fission product yields (neutron induced and spontaneous fission); Neutron reaction cross sections of fission products; Data related to the radioactive decay of fission products; Delayed neutron data of fission products; and lumped fission product data (decay heat, absorption etc.). The seventh issue of this series has been published in July 1981 as INDC(NDS)-116. The present issue includes contributions which were received by NDS between 1 August 1981 and 15 June 1982

  6. Progress in fission product nuclear data

    International Nuclear Information System (INIS)

    Lammer, M.

    1983-08-01

    This is the ninth issue of a report series on Fission Product Nuclear Data (FPND) which is published by the Nuclear Data Section (NDS) of the International Atomic Energy Agency (IAEA). The purpose of this series is to inform scientists working on FPND, or using such data, about all activities in this field which are planned, ongoing, or have recently been completed. The main part of this report consists of unaltered original contributions which the authors have sent to IAEA/NDS. The present issue contains also a section with some recent references relative to fission product nuclear data, which were not covered by the contributions submitted. The types of activities being included in this report are measurements, compilations and evaluations of: Fission product yields (neutron induced and spontaneous fission); Neutron reaction cross sections of fission products; Data related to the radioactive decay of fission products; Delayed neutron data of fission products; and lumped fission product data (decay heat, absorption etc.). The eighth issue of this series has been published in July 1982 as INDC(NDS)-130. The present issue includes contributions which were received by NDS between 1 August 1982 and 25 June 1983

  7. Progress in fission product nuclear data

    International Nuclear Information System (INIS)

    Lammer, M.

    1981-06-01

    This is the seventh issue of a report series on Fission Product Nuclear Data (FPND) which is published by the Nuclear Data Section (NDS) of the International Atomic Energy Agency (IAEA). The purpose of this series is to inform scientists working on FPND, or using such data, about all activities in this field which are planned, ongoing, or have recently been completed. The present issue contains also a section with some recent references relative to fission product nuclear data, which were not covered by the contributions submitted. The types of activities being included in this report are measurements, compilations and evaluations of: fission product yields (neutron induced and spontaneous fission); neutron reaction cross sections of fission products; data related to the radioactive decay of fission products; delayed neutron data of fission products; and lumped fission product data (decay heat, absorption etc.). The sixth issue of this series has been published in June 1980 as INDC(NDS)-113/G+P. The present issue includes contributions which were received by NDS between 1 August 1980 and 25 May 1981

  8. Seventy-five years of nuclear fission

    Indian Academy of Sciences (India)

    the angular distribution of the fragments with the direction of the incident projectile caus- ing fission will depend on .... But in harnessing nuclear energy through the critical fission reactors, disposal of nuclear waste ... experimental technique based on a gridded ion chamber, emission spectra and angular distributions of the ...

  9. Induced-Fission Imaging of Nuclear Material

    International Nuclear Information System (INIS)

    This paper presents initial results from development of the induced-fission imaging technique, which can be used for the purpose of measuring or verifying the distribution of fissionable material in an unopened container. The technique is based on stimulating fissions in nuclear material with 14 MeV neutrons from an associated-particle deuterium-tritium (D-T) generator and counting the subsequent induced fast fission neutrons with an array of fast organic scintillation detectors. For each source neutron incident on the container, the neutron creation time and initial trajectory are known from detection of the associated alpha particle of the d + t → α + n reaction. Many induced fissions will lie along (or near) the interrogating neutron path, allowing an image of the spatial distribution of prompt induced fissions, and thereby fissionable material, to be constructed. A variety of induced-fission imaging measurements have been performed at Oak Ridge National Laboratory with a portable, low-dose D-T generator, including single-view radiographic measurements and three-dimensional tomographic measurements. Results from these measurements will be presented along with the neutron transmission images that have been performed simultaneously. This new capability may have applications to a number of areas in which there may be a need to confirm the presence or configuration of nuclear materials, such as nuclear material control and accountability, quality assurance, treaty confirmation, or homeland security applications.

  10. Some aspects of fission and quasifission processes

    Indian Academy of Sciences (India)

    2015-07-22

    Jul 22, 2015 ... The discovery of nuclear fission in 1938–1939 had a profound influence on the field of nuclear physics and it brought this branch of physics into the forefront as it was recognized for having the potential for its seminal influence on modern society. Although many of the basic features of actinide fission were ...

  11. Incorporation of iodine into calcium phosphates with apatitic structure

    International Nuclear Information System (INIS)

    Coulon, Antoine

    2014-01-01

    In order to avoid the release of 129 I (long-lived intermediate-level waste) in the environment, we describe a novel material incorporating iodine under the form of iodate in a calcium phosphate based hydroxyapatite. This material is prepared by two synthetic processes: a wet precipitation route followed by a spark plasma sintering and a cementitious route. A high iodine content (with a maximum incorporation rate of 10 wt.%) is reached for both processes, by incorporation of the iodate in the apatitic structure. A monolith with relative density of 88.6% was obtained after shaping of the precipitated powders by spark plasma sintering. This material reveals satisfactory leaching properties, with an initial leaching rate in pure water at 50 C of 10 -2 g.m -2 .j -1 , and a residual leaching rate at 50 C of 10 -5 g.m -2 .j -1 in underground water of potential geological repositories. All in all, this material is a potential candidate for the conditioning of radioactive iodine. (author) [fr

  12. Lanthanum germanate-based apatites as electrolyte for SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Marrero-Lopez, D.; Diaz-Carrasco, P.; Ramos-Barrado, J.R. [Departamento de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain); Pena-Martinez, J. [Instituto de Energias Renovables, Parque Tecnologico, Universidad de Castilla La Mancha, 02006 Albacete (Spain); Ruiz-Morales, J.C. [Departamento de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain)

    2011-02-15

    Germanate apatites with composition La{sub 10-x}Ge{sub 5.5}Al{sub 0.5}O{sub 26.75-3x/2} have been evaluated for the first time as possible electrolytes for solid oxide fuel cells (SOFCs). Different electrode materials have been considered in this study, i.e. manganite, ferrite, nickelates and cobaltite as cathode materials; and NiO-CGO composite and chromium-manganite as anodes. The chemical compatibility and electrochemical performance of these electrodes with La{sub 9.8}Ge{sub 5.5}Al{sub 0.5}O{sub 26.45} have been studied by X-ray powder diffraction (XRPD) and impedance spectroscopy. The XRPD analysis did not reveal appreciable bulk reactivity with the formation of reaction products between the germanate electrolyte and these electrodes up to 1,200 C. However, a significant cation interdiffusion was observed by energy dispersive spectroscopy (EDS) at the electrode/electrolyte interface, which leads to a significant decrease of the performance of these electrodes. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Fission Surface Power Technology Development Status

    Science.gov (United States)

    Palac, Donald T.; Mason, Lee S.; Houts, Michael G.; Harlow, Scott

    2010-01-01

    Power is a critical consideration in planning exploration of the surfaces of the Moon, Mars, and beyond. Nuclear power is an important option, especially for locations in the solar system where sunlight is limited in availability or intensity. NASA is maintaining the option for fission surface power for the Moon and Mars by developing and demonstrating technology for an affordable fission surface power system. Because affordability drove the determination of the system concept that this technology will make possible, low development and recurring costs result, while required safety standards are maintained. However, an affordable approach to fission surface power also provides the benefits of simplicity, robustness, and conservatism in design. This paper will illuminate the multiplicity of benefits to an affordable approach to fission surface power, and will describe how the foundation for these benefits is being developed and demonstrated in the Exploration Technology Development Program s Fission Surface Power Project.

  14. Physics of neutron emission in fission

    International Nuclear Information System (INIS)

    Lemmel, H.D.

    1989-06-01

    The document contains the proceedings of the IAEA Consultants' Meeting on the Physics of Neutron Emission in Fission, Mito City (Japan), 24-27 May 1988. Included are the conclusions and recommendations reached at the meeting and the papers presented by the meeting participants. These papers cover the following topics: Energy dependence of the number of fission neutrons ν-bar (3 papers), multiplicity distribution of fission neutrons (3 papers), competition between neutron and γ-ray emission (4 papers), the fission neutron yield in resonances (2 papers) and the energy spectrum of fission neutrons in experiment (9 papers), theory (4 papers) and evaluation (1 paper). A separate abstract was prepared for each of these papers. Refs, figs and tabs

  15. Progress in fission product nuclear data

    International Nuclear Information System (INIS)

    Lammer, G.

    1975-01-01

    This is the first issue of a report series on Fission Product Nuclear Data (FPND), published every six months by the Nuclear Data Section (NDS) of the International Atomic Energy Agency (IAEA). Its purpose is to inform scientists working on FPND, or using such data, about all activities in this field which are planned, ongoing, or have recently been completed. The types of activities being included in this report are measurements, compilations and evaluations of: fission product yields; neutron cross-section data of fission products; data related to β-, γ-decay of fission products; delayed neutron data; and fission product decay-heat. The present issue includes contributions which were received by NDS before 1 November 1975

  16. Fission gas behaviour in water reactor fuels

    International Nuclear Information System (INIS)

    2002-01-01

    During irradiation, nuclear fuel changes volume, primarily through swelling. This swelling is caused by the fission products and in particular by the volatile ones such as krypton and xenon, called fission gas. Fission gas behaviour needs to be reliably predicted in order to make better use of nuclear fuel, a factor which can help to achieve the economic competitiveness required by today's markets. These proceedings communicate the results of an international seminar which reviewed recent progress in the field of fission gas behaviour in light water reactor fuel and sought to improve the models used in computer codes predicting fission gas release. State-of-the-art knowledge is presented for both uranium-oxide and mixed-oxide fuels loaded in water reactors. (author)

  17. Particle tracking

    CERN Document Server

    Safarík, K; Newby, J; Sørensen, P

    2002-01-01

    In this lecture we will present a short historical overview of different tracking detectors. Then we will describe currently used gaseous and silicon detectors and their performance. In the second part we will discuss how to estimate tracking precision, how to design a tracker and how the track finding works. After a short description of the LHC the main attention is drawn to the ALICE experiment since it is dedicated to study new states in hadronic matter at the LHC. The ALICE tracking procedure is discussed in detail. A comparison to the tracking in ATLAS, CMS and LHCb is given. (5 refs).

  18. Contained fissionly vaporized imploded fission explosive breeder reactor

    International Nuclear Information System (INIS)

    Marwick, E.F.

    1978-01-01

    Disclosed is a nuclear reactor system which produces useful thermal power and breeds fissile isotopes wherein large spherical complex slugs containing fissile and fertile isotopes as well as vaporizing and tamping materials are exploded seriatim in a large containing chamber having walls protected from the effects of the explosion by about two thousand tons of slurry of fissile and fertile isotopes in molten alkali metal. The slug which is slightly sub-critical prior to its entry into the centroid portion of the chamber, then becomes slightly more than prompt-critical because of the near proximity of neutron-reflecting atoms and of fissioning atoms within the slurry. The slurry is heated by explosion of the slugs and serves as a working fluid for extraction of heat energy from the reactor. Explosive debris is precipitated from the slurry and used for the fabrication of new slugs

  19. A new approach to measure reaction parameters in the 14.8 meV neutron induced fission of 240Pu and 241Pu

    Science.gov (United States)

    Khan, Naeem A.; Khan, Hameed A.; Gul, Khunab; Akber, Riaz A.; Anwar, Muhammad; Waheed, Abdul; Hussain, Gulzar; Shaikh, M. Saleem

    1980-06-01

    A new approach has been made to use solid state nuclear track detectors in 2π-geometry for studying (a) the fission cross-section, and (b) the angular anisotropy of the fission fragments emitted in the 14.8 MeV neutron induced fission of 240Pu and 241Pu. The results of 2π-geometry arrangements have been compared with those obtained by using the conventional vacuum chamber measurements. The results indicate that with proper adjustments, the 2π-geometry method can cut down the accelerator time by at least a few orders of magnitude as compared to that required by the conventional vacuum chamber arrangements. This facilitates the studies of reactions with two yields. The paper also describes the measurements carried out to determine the spontaneous fission decay constants of the above mentioned isotopes of plutonium. Some preliminary values of other fission parameters have also been quoted.

  20. Aerosols and fission product transport

    International Nuclear Information System (INIS)

    Megaw, W.J.

    1987-12-01

    A survey is presented of current knowledge of the possible role of aerosols in the consequences of in- and out-of-core LOCAs and of end fitting failures in CANDU reactors. An extensive literature search has been made of research on the behaviour of aerosols in possible accidents in water moderated and cooled reactors and the results of various studies compared. It is recommended that further work should be undertaken on the formation of aerosols during these possible accidents and to study their subsequent behaviour. It is also recommended that the fission products behaviour computer code FISSCON II should be re-examined to determine whether it reflects the advances incorporated in other codes developed for light water reactors which have been extensively compared. 47 refs

  1. Geology behind nuclear fission technology

    International Nuclear Information System (INIS)

    Dhana Raju, R.

    2005-01-01

    Geology appears to have played an important role of a precursor to Nuclear Fission Technology (NFT), in the latter's both birth from the nucleus of an atom of and most important application as nuclear power extracted from Uranium (U), present in its minerals. NFT critically depends upon the availability of its basic raw material, viz., nuclear fuel as U and/ or Th, extracted from U-Th minerals of specific rock types in the earth's crust. Research and Development of the Nuclear Fuel Cycle (NFC) depends heavily on 'Geology'. In this paper, a brief review of the major branches of geology and their contributions during different stages of NFC, in the Indian scenario, is presented so as to demonstrate the important role played by 'Geology' behind the development of NFT, in general, and NFC, in particular. (author)

  2. Laser driven fusion fission hybrids

    International Nuclear Information System (INIS)

    Hansen, L.F.; Maniscalco, J.A.

    1977-11-01

    The role of the fusion-fission hybrid reactor (FFHR) as a fissile fuel and/or power producer is discussed. As long range options to supply the world energy needs, hybrid-fueled thermal-burner reactors are compared to liquid metal fast breeder reactors (LMFBR). A discussion of different fuel cycles (thorium, depleted uranium, and spent fuel) is presented in order to compare the energy multiplication, the production of fissile fuel, the laser efficiency and pellet gain requirements of the hybrid reactor. Lawrence Livermore Laboratory (LLL) has collaborated with Bechtel Corporation and with Westinghouse in two engineering design studies of laser fusion driven hybrid power plants. The hybrid designs which have resulted from these two studies are briefly described and analyzed by considering operational parameters, such as energy multiplication, power density, burn-up and plutonium production as a function time

  3. Improvement in crystallinity of apatite coating on titanium with the insertion of CaF2 buffer layer.

    Science.gov (United States)

    Lee, Su-Hee; Kim, Hyoun-Ee; Kim, Hae-Won

    2008-05-01

    In the apatite coatings on Ti the heat treatment process is necessary to crystallize the apatite structure for improved chemical stability and biological properties. However, the heat treatment normally degrades the mechanical strength of the coating layer associated with thermally induced stress. In this study, we aimed to improve the crystallization of apatite coating by using calcium fluoride (CaF2) as a buffer layer. The insertion of a thin layer of CaF2 (0.2-1 microm) between apatite and Ti significantly improved the crystallization behavior of apatite. Moreover, this crystallization was more enhanced as the thickness of CaF2 was increased. When a 1 microm-thick CaF2 was inserted, the crystallization of apatite initiated at a temperature as low as 320 degrees C, being a dramatic improvement in the crystallization when considering the crystallization initiation temperature of a bare apatite coating on Ti was approximately 450 degrees C. As a result of this crystallization enhancement, the dissolution behavior of CaF2-inserted apatite coatings was more stable than that of the bare apatite coating, showing much reduced initial-burst effect. Preliminary cellular assay showed the CaF2-inserted apatite coating provided a substrate for cells to spread and grow favorably, as being similar to the bare apatite coating. This novel way of apatite coating on Ti using CaF2 buffer layer may be useful in the coating systems particularly requiring low temperature processing and increased crystallinity with high chemical stability.

  4. More detailed study of fission dynamics in fusion-fission reactions within a stochastic approach

    Science.gov (United States)

    Nadtochy, P. N.; Adeev, G. D.; Karpov, A. V.

    2002-06-01

    A stochastic approach based on three-dimensional Langevin equations was applied to a more detailed study of fission dynamics in fusion-fission reactions. The dynamical model has been developed and extended to investigate fission characteristics of light fissioning nuclei at low excitation energies. The energy dependences of an anisotropy of the fission fragment angular distribution, an evaporation residue cross section, a fission cross section, mean prescission neutron, and giant dipole γ multiplicities have been analyzed for the 16O+208Pb-induced fission of 224Th. Also, dependence of the prescission neutron multiplicity on the fragment mass asymmetry and total kinetic energy have been calculated. Analysis of the results shows that not only characteristics of the mass-energy distribution of fission fragments, but also the mass and kinetic-energy dependence of the prescission neutron multiplicity, the angular anisotropy, and fission probability can be reproduced using a modified one-body mechanism for nuclear dissipation with a reduction coefficient of the contribution from a wall formula ks=0.25 0.5 for compound nuclei 172Yb, 205Fr, 215Fr, and 224Th. Decrease of the prescission neutron multiplicities with fragment mass asymmetry is due to a decrease of the fission time. The results obtained show that prescission neutrons are evaporated predominantly from the nearly spherical compound nucleus at an early stage of fission process before the saddle point is reached. From performed analysis one can conclude that coordinate-independent reduction coefficient ks is not compatible with simultaneous description of the main fission characteristics for heavy fissioning systems 256Fm and 252Fm.

  5. Adsorption and release of amino acids mixture onto apatitic calcium phosphates analogous to bone mineral

    Science.gov (United States)

    El Rhilassi, A.; Mourabet, M.; El Boujaady, H.; Bennani-Ziatni, M.; Hamri, R. El; Taitai, A.

    2012-10-01

    Study focused on the interaction of adsorbate with poorly crystalline apatitic calcium phosphates analogous to bone mineral. Calcium phosphates prepared in water-ethanol medium at physiological temperature (37 °C) and neutral pH, their Ca/P ratio was between 1.33 and 1.67. Adsorbate used in this paper takes the mixture form of two essential amino acids L-lysine and DL-leucine which have respectively a character hydrophilic and hydrophobic. Adsorption and release are investigated experimentally; they are dependent on the phosphate type and on the nature of adsorbate L-lysine, DL-leucine and their mixture. Adsorption of mixture of amino acids on the apatitic calcium phosphates is influenced by the competition between the two amino acids: L-lysine and DL-leucine which exist in the medium reaction. The adsorption kinetics is very fast while the release kinetics is slow. The chemical composition of apatite has an influence on both adsorption and release. The interactions adsorbate-adsorbent are electrostatic type. Adsorption and release reactions of the amino acid mixture are explained by the existence of the hydrated surface layer of calcium phosphate apatite. The charged sbnd COOsbnd and sbnd NH3+ of adsorbates are the strongest groups that interact with the surface of apatites, the adsorption is mainly due to the electrostatic interaction between the groups sbnd COOsbnd of amino acids and calcium Ca2+ ions of the apatite. Comparative study of interactions between adsorbates (L-lysine, DL-leucine and their mixture) and apatitic calcium phosphates is carried out in vitro by using UV-vis and infrared spectroscopy IR techniques.

  6. The Identification and Synthesis of Lead Apatite Minerals Formed in Lead Water Pipes

    Directory of Open Access Journals (Sweden)

    Jeremy D. Hopwood

    2016-01-01

    Full Text Available Phosphate is added to drinking water in the UK to minimise the release of lead from lead water pipes. The phosphate encourages the formation of insoluble lead apatites on the walls of the pipe. Hydroxylpyromorphite Pb5(PO43OH is the lead apatite that is most often used to model lead levels in tap water; however, its presence has not been confirmed. Our aims were to identify the lead pipe apatite and synthesise it. The synthetic mineral would then be used in future solubility studies to produce better predictions of lead levels in tap water. XRD and FTIR were used to characterise the minerals on a range of lead pipes. Pyromorphite and hydroxylpyromorphite were absent and instead a range of mixed calcium lead apatites were present. For every five lead ions in the general formula Pb5(PO43X between one and two ions were replaced with calcium and there was evidence of substitution of PO43- by either CO32- or HPO42-. Calcium lead apatites with similar unit cell dimensions to those found on lead water pipes were then synthesised. The calcium : lead ratio in these reaction mixtures was in excess of 500 : 1 and the resulting crystals were shown by TEM to be nanosized rods and flakes. The synthetic apatites that most closely resembled the unit cell dimensions of the apatites on lead water pipes were shown to be Pb3.4Ca1.3(PO43Cl0.03OH0.97, Pb3.6Ca1.2(PO43Cl0.07OH0.93, and Pb3.6Ca1.2(PO43Cl0.27OH0.73.

  7. Determination of the fission barrier height in fission of heavy radioactive beams induced by the (d,p)-transfer

    CERN Multimedia

    A theoretical framework is described, allowing to determine the fission barrier height using the observed cross sections of fission induced by the (d,p)-transfer with accuracy, which is not achievable in another type of low-energy fission of neutron-deficient nuclei, the $\\beta$-delayed fission. The primary goal is to directly determine the fission barrier height of proton-rich fissile nuclei, preferably using the radio-active beams of isotopes of odd elements, and thus confirm or exclude the low values of fission barrier heights, typically extracted using statistical calculations in the compound nucleus reactions at higher excitation energies. Calculated fission cross sections in transfer reactions of the radioactive beams show sufficient sensitivity to fission barrier height. In the probable case that fission rates will be high enough, mass asymmetry of fission fragments can be determined. Results will be relevant for nuclear astrophysics and for production of super-heavy nuclei. Transfer induced fission of...

  8. On the mechanism of fission neutron emission

    International Nuclear Information System (INIS)

    Maerten, H.; Richter, D.; Seeliger, D.

    1986-01-01

    This review represents the present knowledge of the mechanism of prompt fission neutron emission. Starting with a brief fission process characterization related with neutron emission, possible emission mechanisms are discussed. It is emphasized that the experimental study of special mechanisms, i.e. scission neutron emission processes, requires a sufficiently correct description of emission probabilities on the base of the main mechanism, i.e. the evaporation from fully accelerated fragments. Adequate statistical-model approaches have to account for the complexity of nuclear fission reflected by an intricate fragment distribution. The present picture of scission neutron emission is not clarified neither experimentally nor theoretically. Deduced data are contradictory and depend on the used analysis procedures often involving rough discriptions of evaporated-neutron distributions. The contribution of two secondary mechanisms of fission neutron emission, i.e. the neutron evaporation during fragment acceleration and neutron emission due to the decay of 5 He after ternary fission, is estimated. We summarize the recent progress of the theoretical description of fission neutron spectra in the framework of statistical models considering the standard spectrum of 252 Cf(sf) neutrons especially. The main experimental basis for the study of fission neutron emission is the accurate measurement of emission probabilities as a function of emission energy and angle (at least) as well as fragment parameters (mass number ratio and kinetic energy). The present status is evaluated. (author)

  9. Effect of surface silanol groups on the deposition of apatite onto silica surfaces: a computer simulation study

    CSIR Research Space (South Africa)

    Mkhonto, D

    2008-01-01

    Full Text Available that bio-active ceramics, including glasses and glass-ceramics, bond to living bone through a collagen-free apatite layer [4], and formation of such an apatite layer on the synthetic material before implantation in the body thus encourages intergrowth... biologically active apatite layer which provides the bonding interface with tissues, such as collagen and other proteins. The sequence of reactions leading to apatite layer formation on bio-active glasses, following immersion in tissue or body fluids is now...

  10. Nuclear fission induced by high energy protons

    International Nuclear Information System (INIS)

    Barashenkov, V.S.; Shmakov, S.Yu.

    1979-01-01

    The fission of 203 Pb, 232 Th, 238 U, 239 Pu, 209 Br nuclei in the energy region T approximately equal to 0.1-2 GeV is considered on the basis of intranuclear cascade model. The competition between fission and evaporation of excited nuclei remaining after the cascade phase of the interaction is taken into account. Fong's model is used to calculate the fission process. The multiplicity of produced particles (d, t, 3 He, α), the energy spectra of neutrons, the distributions of residual nuclei are discussed. The calculated results are compared with the experiment and with the known theoretical data

  11. Fusion barrier distributions and fission anisotropies

    International Nuclear Information System (INIS)

    Hinde, D.J.; Morton, C.R.; Dasgupta, M.; Leigh, J.R.; Lestone, J.P.; Lemmon, R.C.; Mein, J.C.; Newton, J.O.; Timmers, H.; Rowley, N.; Kruppa, A.T.

    1995-01-01

    Fusion excitation functions for 16,17 O+ 144 Sm have been measured to high precision. The extracted fusion barrier distributions show a double-peaked structure interpreted in terms of coupling to inelastic collective excitations of the target. The effect of the positive Q-value neutron stripping channel is evident in the reaction with 17 O. Fission and evaporation residue cross-sections and excitation functions have been measured for the reaction of 16 O+ 208 Pb and the fusion barrier distribution and fission anisotropies determined. It is found that the moments of the fusion l-distribution determined from the fusion and fission measurements are in good agreement. ((orig.))

  12. Recovery and use of fission product noble metals

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, G.A.; Rohmann, C.A.; Perrigo, L.D.

    1980-06-01

    Noble metals in fission products are of strategic value. Market prices for noble metals are rising more rapidly than recovery costs. A promising concept has been developed for recovery of noble metals from fission product waste. Although the assessment was made only for the three noble metal fission products (Rh, Pd, Ru), there are other fission products and actinides which have potential value. (DLC)

  13. Recovery and use of fission product noble metals

    International Nuclear Information System (INIS)

    Jensen, G.A.; Rohmann, C.A.; Perrigo, L.D.

    1980-06-01

    Noble metals in fission products are of strategic value. Market prices for noble metals are rising more rapidly than recovery costs. A promising concept has been developed for recovery of noble metals from fission product waste. Although the assessment was made only for the three noble metal fission products (Rh, Pd, Ru), there are other fission products and actinides which have potential value

  14. Úvahy o původu konkávních tvarů na některých lokalitách karbonských arkóz ve středních a v západních Čechách

    Czech Academy of Sciences Publication Activity Database

    Suchý, V.; Filip, Jiří

    2016-01-01

    Roč. 49, č. 1 (2016), s. 61-67 ISSN 0514-8057 Institutional support: RVO:67985831 Keywords : hypogene speleogenesis * tafoni * arkose sandstone * brine * apatite fission track analysis * Carboniferous * Bohemian Massif, Czech Republic Subject RIV: DB - Geology ; Mineralogy

  15. SSNTD study of the probable influence of alpha activity on the mass distribution of sup 2 sup 5 sup 2 Cf fission fragments

    CERN Document Server

    Paul, D; Sastri, R C; Ghose, D

    1999-01-01

    The SSNTD has come a long way in its application for the study of nuclear phenomena. Spontaneous fission of transuranic elements is one such phenomena wherein use of SSNTD offers easy registration of the signature of the fission fragments. The object of the present study is to explore whether any one of the track parameters such as the diameter can be used to estimate the atomic mass ratios of the spontaneous fission fragments. The spontaneous fission data from sup 2 sup 5 sup 2 Cf recorded almost at the end of one and four half-life periods for alpha decay are analysed, taking a plot of the number of tracks versus the track diameter. From these plots it is seen that initially, when significant alpha activity of sup 2 sup 5 sup 2 Cf persists, the fission fragments appear to cluster into two predominant groups as indicated by two peaks. The ratio of the diameters at these peak positions appear to be related to the ratio of average mass numbers of the light and heavy groups of fission fragments. However, absenc...

  16. Long-term effect of apatite on ectomycorrhizal growth and community structure.

    Science.gov (United States)

    Berner, Christoffer; Johansson, Tomas; Wallander, Håkan

    2012-11-01

    Ectomycorrhizal (ECM) fungi are efficient at taking up phosphorus (P) from mineral sources, such as apatite, which are not easily available to the host trees. Since ECM fungal species differ in P uptake rates, it can be expected that the composition of the ECM fungal community will change upon exposure to apatite, provided that the P transfer is rewarded by more carbon being transferred to the fungal symbiont. Control and apatite-amended mesh bags were buried in pairs in the humus layer of a P-poor Norway spruce forest. The ECM fungal community that colonized these bags was analyzed by DNA extraction, PCR amplification of the internal transcribed spacer (ITS) region, cloning, and random sequencing. Fungal biomass was estimated by ergosterol analysis. No change in the ECM fungal community structure was seen after 5 years of apatite exposure, although the fungal biomass increased threefold upon apatite amendment. Our results indicate that host trees enhance carbon allocation to ECM fungi colonizing P sources in P-poor forests but the lack of change in the composition of the ECM fungal community suggests that P transfer rates were similar among the species. Alternatively, higher P transfer among certain species was not rewarded with higher carbon transfer from the host.

  17. Synthesis and luminescence of Eu2+-doped alkaline-earth apatites for application in white LED

    International Nuclear Information System (INIS)

    Zhang Xinguo; Zhang Jilin; Huang Jinqing; Tang Xueping; Gong Menglian

    2010-01-01

    A series of Eu 2+ -doped alkaline-earth apatites (alkaline-earth=Ca, Sr and Ba) were synthesized by a solid state reaction method with excess chlorides, and the effect of the used excess chlorides on the luminescent property of the synthesized products was discussed. Photoluminescence measurements showed that Eu 2+ -doped calcium apatite exhibited intensely blue wide-band emission peaking at 457 nm under near UV excitation among the Eu 2+ -doped Ca, Sr and Ba apatites. Blue and white LEDs were successfully fabricated by pre-coating the calcium apatite phosphors onto ∼395 nm-emitting InGaN chips. The CIE coordinates, color temperature, luminous efficacy and rendering index value of the fabricated white LED are (0.3432, 0.3234), 4969 K, 8 lm/W and 80, respectively. The results indicate that the Eu 2+ -activated calcium apatite phosphor is a promising candidate as a blue component for fabrication of near UV-based white LEDs.

  18. Study of thermoluminescence properties of Eppawala apatite mineral and its suitability as a dosimetric material

    CERN Document Server

    Jayalath, A

    2000-01-01

    This study reports TL properties and the dosimetric properties of natural apatite mineral obtained from Eppawala Apatite ore in Sri Lanka. This mineral was used to study glow curve characteristics by using (a) the powder form of the raw mineral (b) sieved raw mineral and (c) the magnetically separated mineral. The glow curves of magnetically separated apatite showed two peaks. Low temperature peak at 120C, and a high temperature peak at 240C. The emission wavelength of the glow curve is 360 nm. The intensity of the 240C peak become stronger after annealing the mineral to about 180C. Apatite has glow peaks similar to other commonly used TL materials, such as synthetically prepared calcium sulphate:Dy and calcium sulphate:Tm show high intensity peak at 220C and low intensity peaks at 80C and 120C. However, the emission wavelengths of the main peaks are at 428nm and 452 nm for calcium sulphate:Dy and calcium sulphate: Tm respectively. Eppawala apatite mineral showed a linear response to both gamma and beta radia...

  19. Freeze-casting for PLGA/carbonated apatite composite scaffolds: Structure and properties.

    Science.gov (United States)

    Schardosim, M; Soulié, J; Poquillon, D; Cazalbou, S; Duployer, B; Tenailleau, C; Rey, C; Hübler, R; Combes, C

    2017-08-01

    This paper focuses on the fabrication of three-dimensional porous PLGA-biomimetic carbonated apatite composite scaffolds by freeze-casting and using dimethyl carbonate as a solvent. Several charge/polymer ratios were tested in order to finely understand the influence of the filler rate on the scaffold porosity and mechanical and degradation properties using complementary characterization techniques (SEM, mercury porosimetry and X-ray microtomography). It was demonstrated that the apatite ratio within the composite scaffold has a strong influence in terms of architecture, material cohesion, mechanical properties and in vitro degradation properties. An optimum biomimetic apatite ratio was reached to combine good mechanical properties (higher rigidity) and material cohesion. In vitro degradation studies showed that higher apatite filler rates limited PLGA degradation and enhanced the hydrophilicity of the scaffolds which is expected to improve the biological properties of the scaffolds in addition to the bioactivity related to the presence of the apatite analogous to bone mineral. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Neutron emission as a probe of fusion-fission and quasi-fission dynamics

    International Nuclear Information System (INIS)

    Hinde, D.J.

    1991-01-01

    Pre- and post scission neutron yeilds have been measured as a function of projectile mass, compound nucleus fissility, and fission mass-split and total kinetic energy (TKE) for 27 fusion-fission and quasi-fission reactions induced by beams of 16,18 O, 40 Ar and 64 Ni. A new method of interpretation of experimental pre-scission neutron multiplicities ν-pre and mean kinetic energies ε ν allows the extraction of fission time scales with much less uncertainty than previously, all fusion-fission results being consistent with a dynamical time scale of (35±15) x 10 -21 s for symmetric fission. All reactions show that ν-pre falls quite rapidly with increasing mass-asymmetry; evidence is presented that for fusion-fission reactions this is partly due to a reduction of the dynamical fission time scale with mass-asymmetry. For quasi-fission, the data indicate that the pre-scission multiplicity and mean neutron kinetic energy are very sensitive to the final mass-asymmetry, but that the time scale is virtually independent of mass-asymmetry. It is concluded that for fusion-fission there is no dependence of ν-pre on TKE, whilst for 64 Ni-induced quasi-fission reactions, a strong increase of ν-pre with decreasing TKE is observed, probably largely caused by neutron emission during the acceleration time of the fission fragments in these fast reactions. Interpretation of post-scission multiplicities in terms of fragment excitation energies leads to deduced time scales consistent with those determined from the pre-scission data. 54 refs., 17 tabs., 25 figs

  1. Determination of the fission products yields, lanthanide and yttrium, in the fission of 238U with neutrons of fission spectra

    International Nuclear Information System (INIS)

    Nicoli, I.G.

    1981-06-01

    A radiochemical investigation is performed to measure the cumulative fission product yields of several lantanides and yttrium nuclides in the 238 U by fission neutron spectra. Natural and depleted uranium are irradiated under the same experimental conditions in order to find a way to subtract the contribution of the 235 U fission. 235 U percentage in the natural uranium was 3.5 times higher than in the depleted uranium. Uranium oxides samples are irradiated inside the core of the Argonaut Reactor, at the Instituto de Engenharia Nuclear, and the lantanides and yttrium are chemically separated. The fission products gamma activities were detected, counted and analysed in a system constituted by a high resolution Ge(Li) detector, 4096 multichannel analyser and a PDP-11 computer. Cumulative yields for fission products with half-lives between 1 to 33 hours are measured: 93 Y, 141 La, 142 La, 143 Ce and 149 Nd. The chain total yields are calculated. The cumulative fission yields measured for 93 Y, 141 La, 142 La, 143 Ce and 149 Nd are 4,49%, 4,54%, 4,95%, 4,16% and 1,37% respectively and they are in good agreement with the values found in the literature. (Author) [pt

  2. (d,p)-transfer induced fission of heavy radioactive beams

    CERN Document Server

    Veselsky, Martin

    2012-01-01

    (d,p)-transfer induced fission is proposed as a tool to study low energy fission of exotic heavy nuclei. Primary goal is to directly determine the fission barrier height of proton-rich fissile nuclei, preferably using the radio-active beams of isotopes of odd elements, and thus confirm or exclude the low values of fission barrier heights, typically extracted using statistical calculations in the compound nucleus reactions at higher excitation energies. Calculated fission cross sections in transfer reactions of the radioactive beams show sufficient sensitivity to fission barrier height. In the probable case that fission rates will be high enough, mass asymmetry of fission fragments can be determined. Results will be relevant for nuclear astrophysics and for production of super-heavy nuclei. Transfer induced fission offers a possibility for systematic study the low energy fission of heavy exotic nuclei at the ISOLDE.

  3. Independent fission yields of Rb and Cs from thermal-neutron-induced fission of 239Pu

    International Nuclear Information System (INIS)

    Balestrini, S.J.; Forman, L.

    1975-01-01

    The relative independent fission yields of Rb and Cs from thermal-neutron-induced fission of 239 Pu have been measured on line using a mass spectrograph and thermalized neutrons from a burst reactor. Independent yields were derived by normalizing the measurements to products of chain yields and fractional independent yields, estimating the latter from measured cumulative yields of Kr and Xe. Comparing the independent yields with those from 238 U fission, the 239 Pu results show shifts in isotopic yield distribution toward lower mass for both Rb and Cs and also toward the production of more Cs and less Rb when 239 Pu is fissioned

  4. Angular momenta of fission fragments in the {alpha}-accompanied fission of {sup 252}Cf

    Energy Technology Data Exchange (ETDEWEB)

    Jandel, M.; Kliman, J.; Krupa, L.; Morhac, M. [Slovak Academy of Sciences, Department of Nuclear Physics, Bratislava (Slovakia); Joint Institute for Nuclear Research, Flerov Laboratory for Nuclear Reactions, Dubna (Russian Federation); Hamilton, J.H.; Kormicki, J.; Ramayya, A.V.; Hwang, J.K.; Luo, Y.X.; Fong, D.; Gore, P. [Vanderbilt University, Department of Physics, Nashville, TN (United States); Ter-Akopian, G.M.; Oganessian, Yu.Ts.; Rodin, A.M.; Fomichev, A.S.; Popeko, G.S. [Joint Institute for Nuclear Research, Flerov Laboratory for Nuclear Reactions, Dubna (Russian Federation); Daniel, A.V. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Rasmussen, J.O.; Macchiavelli, A.O.; Stoyer, M.A. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Donangelo, R.; Cole, J.D.

    2005-06-01

    For the first time, average angular momenta of the ternary fission fragments {sup 100,102}Zr, {sup 106}Mo, {sup 144,146}Ba and {sup 138,140,142}Xe from the {alpha}-accompanied fission of {sup 252}Cf were obtained from relative intensities of prompt {gamma}-ray transitions with the use of the statistical model calculation. Average values of the angular momenta were compared with the corresponding values for the same fission fragments from the binary fission of {sup 252}Cf. Results indicate the presence of a decreasing trend in the average values of angular momenta induced in ternary fission fragments compared to the same binary fission fragments. On the average, the total angular momentum extracted for ternary fission fragments is {proportional_to}1.4{Dirac_h} lower than in binary fission. Consequently, results indicate that the mechanism of the ternary {alpha}-particles emission may directly effect an induction of angular momenta of fission fragments, and possible scenarios of such mechanisms are discussed. Further, the dependence of the angular momenta of {sup 106}Mo and {sup 140}Xe on the number of emitted neutrons from correlated pairs of primary fragments was obtained also showing a decreasing dependence of average angular momenta with increasing number of emitted neutrons. Consequences are briefly discussed. (orig.)

  5. Timber tracking

    DEFF Research Database (Denmark)

    Düdder, Boris; Ross, Omry

    2017-01-01

    Managing and verifying forest products in a value chain is often reliant on easily manipulated document or digital tracking methods - Chain of Custody Systems. We aim to create a new means of tracking timber by developing a tamper proof digital system based on Blockchain technology. Blockchain...

  6. Development of fission Mo-99 production technology

    International Nuclear Information System (INIS)

    Park, Jin Ho; Choung, W. M.; Lee, K. I. and others

    2000-05-01

    Fission Mo-99 is the only parent nuclide of Tc-99m, an extremely useful tool for mdeical diagnosis, with an estimated usage of greater than 80% of nuclear medicine applicatons. HEU and LEU targets to optimize in HANARO irradiation condition suggested and designed for domestic production of fission Mo-99. The optimum process conditions are established in each unit process to meet quality requirements of fission Mo-99 products, and the results of performance test in combined process show Mo separation and purification yield of the above 97%. The concept of Tc generator production process is established, and the result of performance test show Tc production yield of 98.4% in Tc generator procuction process. The drafts is prepared for cooperation of technical cooperation and business investment with foreign country. Evaluation on economic feasibility is accompanied for fission Mo-99 and Tc-99m generator production

  7. Energy from nuclear fission an introduction

    CERN Document Server

    De Sanctis, Enzo; Ripani, Marco

    2016-01-01

    This book provides an overview on nuclear physics and energy production from nuclear fission. It serves as a readable and reliable source of information for anyone who wants to have a well-balanced opinion about exploitation of nuclear fission in power plants. The text is divided into two parts; the first covers the basics of nuclear forces and properties of nuclei, nuclear collisions, nuclear stability, radioactivity, and provides a detailed discussion of nuclear fission and relevant topics in its application to energy production. The second part covers the basic technical aspects of nuclear fission reactors, nuclear fuel cycle and resources, safety, safeguards, and radioactive waste management. The book also contains a discussion of the biological effects of nuclear radiation and of radiation protection, and a summary of the ten most relevant nuclear accidents. The book is suitable for undergraduates in physics, nuclear engineering and other science subjects. However, the mathematics is kept at a level that...

  8. Development of fission Mo-99 production technology

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Ho; Choung, W. M.; Lee, K. I. and others

    2000-05-01

    Fission Mo-99 is the only parent nuclide of Tc-99m, an extremely useful tool for mdeical diagnosis, with an estimated usage of greater than 80% of nuclear medicine applicatons. HEU and LEU targets to optimize in HANARO irradiation condition suggested and designed for domestic production of fission Mo-99. The optimum process conditions are established in each unit process to meet quality requirements of fission Mo-99 products, and the results of performance test in combined process show Mo separation and purification yield of the above 97%. The concept of Tc generator production process is established, and the result of performance test show Tc production yield of 98.4% in Tc generator procuction process. The drafts is prepared for cooperation of technical cooperation and business investment with foreign country. Evaluation on economic feasibility is accompanied for fission Mo-99 and Tc-99m generator production.

  9. Fission cross section measurements at intermediate energies

    International Nuclear Information System (INIS)

    Laptev, Alexander

    2005-01-01

    The activity in intermediate energy particle induced fission cross-section measurements of Pu, U isotopes, minor actinides and sub-actinides in PNPI of Russia is reviewed. The neutron-induced fission cross-section measurements are under way in the wide energy range of incident neutrons from 0.5 MeV to 200 MeV at the GNEIS facility. In number of experiments at the GNEIS facility, the neutron-induced fission cross sections were obtained for many nuclei. In another group of experiments the proton-induced fission cross-section have been measured for proton energies ranging from 200 to 1000 MeV at 100 MeV intervals using the proton beam of PNPI synchrocyclotron. (author)

  10. Uranium deposits obtention for fission chambers

    International Nuclear Information System (INIS)

    Artacho Saviron, E.

    1972-01-01

    The obtention of uranium deposits of the required quality for small cylindrical fission chambers presents some difficulties. With the method of electroplating here described the uniformity, reproducibility and adherence of the obtained deposits were satisfactory. (Author) 6 refs

  11. Decay and fission of the oriented nuclei

    CERN Document Server

    Kadmenskij, S G

    2002-01-01

    The fragment angular distributions for binary decay of oriented spherical and deformed nuclei with taking into account the correct transformational properties of wave functions under time inversion have been investigated. It has been shown that for description of fragment angular distributions the adiabatic approximation for collective rotational nuclear degrees of freedom is not correct. It has been demonstrated that this approximation is valid for description of spontaneous and induced low-energy nuclear fission. The dependence of partial fission widths on the orientation of the internal axes spins, projections of spins, and relative angular moments of fission fragments has been analyzed. It has been shown that the adiabatic approximation results in coherent interference of wave functions of fragments relative movement. This interference forms fragments the universal angular distributions of fission fragments for oriented nuclei. For these distributions the deviations from A. Bohr's formula have been invest...

  12. New polymers for nuclear track detection

    International Nuclear Information System (INIS)

    Mascarenhas, Adlete A.A.; Tilve, S.G.; Nadkarni, V.S.

    2004-01-01

    Polymeric track detectors of higher sensitivity were developed from a novel monomer, called NADAC, prepared from diethanolamine. NADAC was homopolymerised using peroxydicarbonate initiators by the radical catalyzed bulk polymerization using an indigenously designed mold to give a 500-micron thick polymer film, henceforth referred to as PNADAC. Also a copolymer of NADAC and ADC monomer has been prepared in a similar way. The above materials were used for recording autoradiographs of 23 '9Pu alpha particles source and also for 252 Cf fission fragment detection. The etching parameters of the newly developed films have been compared with that of the commercially available CR-39 track detector. (author)

  13. Mass and Charge Distribution in Low-Energy Fission

    International Nuclear Information System (INIS)

    Wahl, A.C.

    1965-01-01

    The mass and charge distributions for thermal-neutron fission of U 235 are discussed in considerable detail and compared with the corresponding distributions in other low-energy fission processes. Points discussed in connection with the mass distributions for binary fission include the positions of the peaks, valley and fine structure in a mass yield curve with respect to filled nuclear shells and the changes in the positions that occur with changing fissioning nucleus and excitation energy. The mass distribution from ternary fission is discussed also. For both binary and ternary fission comments are made concerning the mass distributions of primary fragments (before neutron evaporation) and of fission products (after neutron evaporation). Charge distribution is discussed in terms of charge dispersion among fission products with the same mass number and the variation with mass number of Zp, the ''most probable charge'' (non-integral) for a given mass number. Although direct information about charge distribution is limited to fission products, estimates are presented of charge distribution for primary fission fragments. Knowledge and estimates of mass and charge distribution for a fission process allow estimation of primary yields of all fission products or fragments. Although many estimated primary yields are quite uncertain mainly because of lack of knowledge of charge distribution, especially for fission products formed in low yield; some estimates of primary yields are presented to illustrate the need for and possible practicality of further experimentation. Fission processes other than thermal-neutron fission of U 235 that are discussed include thermal-neutron fission of U 233 and Pu 239 , spontaneous fission of Pu 240 and Cf 252 , 14-MeV neutron fission of U 235 and U 238 , 11-MeV proton fission of Ra 226 and 22-MeV deuteron fission of Bi 209 . (author) [fr

  14. A revised calculational model for fission

    International Nuclear Information System (INIS)

    Atchison, F.

    1998-09-01

    A semi-empirical parametrization has been developed to calculate the fission contribution to evaporative de-excitation of nuclei with a very wide range of charge, mass and excitation-energy and also the nuclear states of the scission products. The calculational model reproduces measured values (cross-sections, mass distributions, etc.) for a wide range of fissioning systems: Nuclei from Ta to Cf, interactions involving nucleons up to medium energy and light ions. (author)

  15. Hyperfission - a new mode of nuclear fission

    International Nuclear Information System (INIS)

    Ion, D.B.; Ivascu, M.; Ion-Mihai, R.

    1988-02-01

    In this paper the nuclear hyperfission as a new mode of fission, possible for heavy elements with Z > 92, is investigated. The Q-systematics, hyperfissibility parameters, hyperfission barrier as well as the essential hindrance factors are presented. The hyperfission hindrance factor relative to that of fission is found to be in the interval 1.0x10 -17 - 3.4x10 -16 for the parent nuclei with Z = 92-108. (orig.)

  16. Live Cell Imaging in Fission Yeast.

    Science.gov (United States)

    Mulvihill, Daniel P

    2017-10-03

    Live cell imaging complements the array of biochemical and molecular genetic approaches to provide a comprehensive insight into functional dependencies and molecular interactions in fission yeast. Fluorescent proteins and vital dyes reveal dynamic changes in the spatial distribution of organelles and the proteome and how each alters in response to changes in environmental and genetic composition. This introduction discusses key issues and basic image analysis for live cell imaging of fission yeast. © 2017 Cold Spring Harbor Laboratory Press.

  17. Transport properties of fission product vapors

    International Nuclear Information System (INIS)

    Im, K.H.; Ahluwalia, R.K.

    1983-07-01

    Kinetic theory of gases is used to calculate the transport properties of fission product vapors in a steam and hydrogen environment. Provided in tabular form is diffusivity of steam and hydrogen, viscosity and thermal conductivity of the gaseous mixture, and diffusivity of cesium iodide, cesium hydroxide, diatomic tellurium and tellurium dioxide. These transport properties are required in determining the thermal-hydraulics of and fission product transport in light water reactors

  18. Modeling Fission Product Sorption in Graphite Structures

    International Nuclear Information System (INIS)

    Szlufarska, Izabela; Morgan, Dane; Allen, Todd

    2013-01-01

    The goal of this project is to determine changes in adsorption and desorption of fission products to/from nuclear-grade graphite in response to a changing chemical environment. First, the project team will employ principle calculations and thermodynamic analysis to predict stability of fission products on graphite in the presence of structural defects commonly observed in very high-temperature reactor (VHTR) graphites. Desorption rates will be determined as a function of partial pressure of oxygen and iodine, relative humidity, and temperature. They will then carry out experimental characterization to determine the statistical distribution of structural features. This structural information will yield distributions of binding sites to be used as an input for a sorption model. Sorption isotherms calculated under this project will contribute to understanding of the physical bases of the source terms that are used in higher-level codes that model fission product transport and retention in graphite. The project will include the following tasks: Perform structural characterization of the VHTR graphite to determine crystallographic phases, defect structures and their distribution, volume fraction of coke, and amount of sp2 versus sp3 bonding. This information will be used as guidance for ab initio modeling and as input for sorptivity models; Perform ab initio calculations of binding energies to determine stability of fission products on the different sorption sites present in nuclear graphite microstructures. The project will use density functional theory (DFT) methods to calculate binding energies in vacuum and in oxidizing environments. The team will also calculate stability of iodine complexes with fission products on graphite sorption sites; Model graphite sorption isotherms to quantify concentration of fission products in graphite. The binding energies will be combined with a Langmuir isotherm statistical model to predict the sorbed concentration of fission products

  19. Modeling Fission Product Sorption in Graphite Structures

    Energy Technology Data Exchange (ETDEWEB)

    Szlufarska, Izabela [University of Wisconsin, Madison, WI (United States); Morgan, Dane [University of Wisconsin, Madison, WI (United States); Allen, Todd [University of Wisconsin, Madison, WI (United States)

    2013-04-08

    The goal of this project is to determine changes in adsorption and desorption of fission products to/from nuclear-grade graphite in response to a changing chemical environment. First, the project team will employ principle calculations and thermodynamic analysis to predict stability of fission products on graphite in the presence of structural defects commonly observed in very high- temperature reactor (VHTR) graphites. Desorption rates will be determined as a function of partial pressure of oxygen and iodine, relative humidity, and temperature. They will then carry out experimental characterization to determine the statistical distribution of structural features. This structural information will yield distributions of binding sites to be used as an input for a sorption model. Sorption isotherms calculated under this project will contribute to understanding of the physical bases of the source terms that are used in higher-level codes that model fission product transport and retention in graphite. The project will include the following tasks: Perform structural characterization of the VHTR graphite to determine crystallographic phases, defect structures and their distribution, volume fraction of coke, and amount of sp2 versus sp3 bonding. This information will be used as guidance for ab initio modeling and as input for sorptivity models; Perform ab initio calculations of binding energies to determine stability of fission products on the different sorption sites present in nuclear graphite microstructures. The project will use density functional theory (DFT) methods to calculate binding energies in vacuum and in oxidizing environments. The team will also calculate stability of iodine complexes with fission products on graphite sorption sites; Model graphite sorption isotherms to quantify concentration of fission products in graphite. The binding energies will be combined with a Langmuir isotherm statistical model to predict the sorbed concentration of fission

  20. Overview of tritium fast-fission yields

    International Nuclear Information System (INIS)

    Tanner, J.E.

    1981-03-01

    Tritium production rates are very important to the development of fast reactors because tritium may be produced at a greater rate in fast reactors than in light water reactors. This report focuses on tritium production and does not evaluate the transport and eventual release of the tritium in a fast reactor system. However, if an order-of-magnitude increase in fast fission yields for tritium is confirmed, fission will become the dominant production source of tritium in fast reactors

  1. Fission of Al, Ti, Co, Zr, Nb, Ag, In, Nd, Sm, and Ta nuclei induced by 0.8-1.8 GeV photons

    International Nuclear Information System (INIS)

    Lima, D.A. de; Martins, J.B.; Tavares, O.A.P.

    1989-01-01

    Samples of Al, Ti, Co, Zr, Nb, Ag, In, Nd, Sm, and Ta elements in contact with solid state nuclear track detectors were exposed to 0.8-1.8 GeV bremsstrahlung beams at the 2.5-GeV Electron Synchrotron of the Bonn University. The detectors were processed to produce visible fission tracks for track analysis with optical microscopes. Absolute mean cross section per photon and fissility were evaluated. Results are discussed and compared with other photofission data as well as with estimates from the current fission models. A broad minimum found for nuclear fissility of 10 -4 -10 -3 covering the range 15 approx Z 2 /A approx 25 seems to confirm the predictions from the models. For Al and Ti nuclei the probability of fission amounts to approx 10 -1 . (author) [pt

  2. Experimental Studies of quasi-fission reactions

    International Nuclear Information System (INIS)

    Back, B.B.

    1989-01-01

    A large number of recent experimental studies have shown that a substantial fraction of the total reaction cross section in heavy-ion reactions is found in fission-like processes, which do not result from the fission decay of a completely fused system. Following the suggestion of Swiatecki such processes, which represents a complete relaxation of the relative kinetic energy and a substantial amount of net mass transfer between the two fragments, are denoted quasi-fission reactions. They are distinct from compound fission reactions by bypassing the stage of a completely fused system. This typically means that they are associated with short reaction times, which results in several measurable characteristics such as broken forward-backward symmetries, large anisotropies of the angular distributions and increased widths of the fragment mass distributions. The distinction between quasi-fission and deep inelastic reactions is less stringent and has the character of a gradual evolution from one reaction type to the other, as found also as quasi-elastic reaction evolves into deeply inelastic processes as a function of the total kinetic energy loss. In the present paper some of the experimental data characterizing quasi-fission reactions are reviewed and discussed. (author)

  3. Spontaneous fission of the heaviest elements

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, D.C.

    1989-04-01

    Although spontaneous fission was discovered in /sup 238/U in 1940, detailed studies of the process were first made possible in the 1960's with the availability of milligram quantities of /sup 252/Cf. The advent of solid-state detectors made it possible to perform measurements of coincident fission fragments from even very short-lived spontaneous fission activities or those available in only very small quantities. Until 1971 it was believed that the main features of the mass and kinetic-energy distributions were essentially the same as those for thermal neutron-induced fission and that all low-energy fission proceeded via asymmetric mass division with total kinetic energies which could be derived by linear extrapolation from those of lighter elements. In 1971, measurements of /sup 257/Fm showed an increase in symmetric mass division with anomalously high TKE's. Subsequent experiments showed that in /sup 258/Fm and /sup 259/Fm, the most probable mass split was symmetric with very high total kinetic energy. Measurements for the heavier elements have shown symmetric mass distributions with both high and low total kinetic energies. Recent results for spontaneous fission properties of the heaviest elements are reviewed and compared with theory. 31 refs., 8 figs., 1 tab.

  4. PNNL Apatite Investigation at 100-NR-2 Quality Assurance Project Plan

    Energy Technology Data Exchange (ETDEWEB)

    Fix, N. J.

    2009-04-02

    In 2004, the U.S. Department of Energy, Fluor Hanford, Inc., Pacific Northwest National Laboratory (PNNL), and the Washington Department of Ecology agreed that the long-term strategy for groundwater remediation at the 100-N Area would include apatite sequestration as the primary treatment, followed by a secondary treatment if necessary. Since then, the agencies have worked together to agree on which apatite sequestration technology has the greatest chance of reducing strontium-90 flux to the Columbia River. This Quality Assurance Project Plan provides the quality assurance requirements and processes that will be followed by staff working on the PNNL Apatite Investigation at 100-NR-2 Project. The plan is designed to be used exclusively by project staff.

  5. Fission of Polyanionic Metal Clusters

    Science.gov (United States)

    König, S.; Jankowski, A.; Marx, G.; Schweikhard, L.; Wolfram, M.

    2018-04-01

    Size-selected dianionic lead clusters Pbn2 -, n =34 - 56 , are stored in a Penning trap and studied with respect to their decay products upon photoexcitation. Contrary to the decay of other dianionic metal clusters, these lead clusters show a variety of decay channels. The mass spectra of the fragments are compared to the corresponding spectra of the monoanionic precursors. This comparison leads to the conclusion that, in the cluster size region below about n =48 , the fission reaction Pbn2 -→Pbn-10 -+Pb10- is the major decay process. Its disappearance at larger cluster sizes may be an indication of a nonmetal to metal transition. Recently, the pair of Pb10- and Pbn-10 - were observed as pronounced fragments in electron-attachment studies [S. König et al., Int. J. Mass Spectrom. 421, 129 (2017), 10.1016/j.ijms.2017.06.009]. The present findings suggest that this combination is the fingerprint of the decay of doubly charged lead clusters. With this assumption, the dianion clusters have been traced down to Pb212 -, whereas the smallest size for the direct observation was as high as n =28 .

  6. Fission-fusion neutron source

    Science.gov (United States)

    Yu, Jinnan; Yu, Gang

    2009-04-01

    In order to meet the requirements of fusion power reactors and nuclear waste treatment, a concept of fission-fusion neutron source is proposed, which consists of a LiD assembly located in the heavy water region of the China Advanced Research Reactor. This assembly of LiD fuel rods will be irradiated with slow neutrons and will produce fusion neutrons in the central hole via the reaction 6Li(n, α). More precisely, tritium ions with a high energy of 2.739 MeV will be produced in LiD by the impinging slow neutrons. The tritium ions will in turn bombard the deuterium ions present in the LiD assembly, which will induce fusion reaction and then the production of 14 MeV neutrons. The fusion reaction rate will increase with the accumulation of tritium in LiD by the reaction between tritium and deuteron recoils produced by the 14 MeV neutrons. When the concentration of tritium reaches 0.5 · 10 22 and the fraction of fusion reactions between tritium and deuteron recoils approaches 1, the 14 MeV neutron flux is doubled and redoubled, an so forth, approaching saturation in which the tritium produced at a time t is exhausted by the fusion reactions to keep constant the tritium concentration in LiD.

  7. Theoretical stability assessment of uranyl phosphates and apatites: Selection of amendments for in situ remediation of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Raicevic, S. [Institute of Nuclear Sciences VINCA, Radiation and Environmental Protection Laboratory, P.O.Box 522, 11001 Belgrade (Serbia and Montenegro)]. E-mail: raich@beotel.yu; Wright, J.V. [PIMS NW, Inc., 201 North Edison, Suite 226, Richland, WA 99336 (United States); Veljkovic, V. [Institute of Nuclear Sciences VINCA, Center for Multidisciplinary Research and Engineering, P.O.Box 522, 11001 Belgrade (Serbia and Montenegro); Conca, J.L. [Los Alamos National Laboratory, 115 North Main Street, Carlsbad, NM 88220 (United States)

    2006-02-15

    Addition of an amendment or reagent to soil/sediment is a technique that can decrease mobility and reduce bioavailability of uranium (U) and other heavy metals in the contaminated site. According to data from literature and results obtained in field studies, the general mineral class of apatites was selected as a most promising amendment for in situ immobilization/remediation of U. In this work we presented theoretical assessment of stability of U(VI) in four apatite systems (hydroxyapatite (HAP), North Carolina Apatite (NCA), Lisina Apatite (LA), and Apatite II) in order to determine an optimal apatite soil amendment which could be used for in situ remediation of uranium. In this analysis we used a theoretical criterion which is based on calculation of the ion-ion interaction potential, representing the main term of the cohesive energy of the matrix/pollutant system. The presented results of this analysis indicate (i) that the mechanism of immobilization of U by natural apatites depends on their chemical composition and (ii) that all analyzed apatites represent, from the point of view of stability, promising materials which could be used in field remediation of U-contaminated sites.

  8. Theoretical stability assessment of uranyl phosphates and apatites: Selection of amendments for in situ remediation of uranium

    International Nuclear Information System (INIS)

    Raicevic, S.; Wright, J.V.; Veljkovic, V.; Conca, J.L.

    2006-01-01

    Addition of an amendment or reagent to soil/sediment is a technique that can decrease mobility and reduce bioavailability of uranium (U) and other heavy metals in the contaminated site. According to data from literature and results obtained in field studies, the general mineral class of apatites was selected as a most promising amendment for in situ immobilization/remediation of U. In this work we presented theoretical assessment of stability of U(VI) in four apatite systems (hydroxyapatite (HAP), North Carolina Apatite (NCA), Lisina Apatite (LA), and Apatite II) in order to determine an optimal apatite soil amendment which could be used for in situ remediation of uranium. In this analysis we used a theoretical criterion which is based on calculation of the ion-ion interaction potential, representing the main term of the cohesive energy of the matrix/pollutant system. The presented results of this analysis indicate (i) that the mechanism of immobilization of U by natural apatites depends on their chemical composition and (ii) that all analyzed apatites represent, from the point of view of stability, promising materials which could be used in field remediation of U-contaminated sites

  9. The study of geochemical behavior of rare earth elements in apatites from the Hormoz Island, Persian Gulf

    Directory of Open Access Journals (Sweden)

    Ali Rostami

    2014-04-01

    Full Text Available The study area is located about 3 km southwest of the Hormoz Island in the Hormozgan province, in the Persian Gulf. The main rock units in the region consist of a highly altered acidic pluton cratophyre, which is responsible for apatite formation, diabasic dike, marl and altered basalt. Apatite is the only phosphate mineral in the Hormoz Island, which has accumulated REE in its crystal structure. The amount of Na2O and SiO2 oxides in apatite are high and the average content of the main elements Fe, Mg, Al, Ca are 7.5 ppm, 365 ppm, 2880 ppm and 27.8%, respectively. The Y, Mn, Rb contents increase and Sr decreases with increasing magmatic differentiation. It shows that a moderate magmatic differentiation occurred during the crystallization of apatite. The total REE content in the Hormoz apatite is high (1.22-2.25%. LREE/HREE ratio is also high. This means that Hormoz apatites are enriched in light rare earth elements. The REE normalized pattern shows a negative slope with a negative Eu anomaly. According to various diagrams based on apatite composition, it is deduced that the Hormoz apatites belong to mafic I-type granitoids with high oxidation state (Fe2O3/FeO>1.

  10. A new glance at ruthenium sorption mechanism on hydroxy, carbonate, and fluor apatites: Analytical and structural studies.

    Science.gov (United States)

    Tõnsuaadu, K; Gruselle, M; Villain, F; Thouvenot, R; Peld, M; Mikli, V; Traksmaa, R; Gredin, P; Carrier, X; Salles, L

    2006-12-15

    The sorption mechanism of Ru3+ ions on hydroxy (HAp), carbonate (CO3HAp), and fluor apatites (FAp) has been studied in detail. Ru apatites were obtained by reaction of the apatites with RuCl3 in aqueous solution. The structure and composition of the ruthenium-modified apatites were studied by several techniques: elemental analysis, XRD, EXAFS, IR, NMR, SEM-EDS, TEM, and thermal analysis. The amount of Ru in the modified apatite varies from 7.8 to 10.5 wt% and is not related to the initial composition or the specific surface area of the apatite. The different characterization techniques show that in the Ru-modified apatites Ru is surrounded by six oxygen atoms and do not contain any chlorine. For Ru-HAp and Ru-CO3HAp the new phase is amorphous whereas it is crystalline for FAp. The catalytic oxidation ability is higher for Ru-HAp and Ru-CO3HAp compared to Ru-FAp apatite in the oxidation of benzylic alcohol.

  11. Pacific Northwest National Laboratory Apatite Investigation at the 100-NR-2 Quality Assurance Project Plan

    Energy Technology Data Exchange (ETDEWEB)

    Fix, N. J.

    2008-03-28

    This Quality Assurance Project Plan provides the quality assurance requirements and processes that will be followed by staff working on the 100-NR-2 Apatite Project. The U.S. Department of Energy, Fluor Hanford, Inc., Pacific Northwest National Laboratory, and the Washington Department of Ecology agreed that the long-term strategy for groundwater remediation at 100-N would include apatite sequestration as the primary treatment, followed by a secondary treatment. The scope of this project covers the technical support needed before, during, and after treatment of the targeted subsurface environment using a new high-concentration formulation.

  12. Chemical, physical, and histologic studies on four commercial apatites used for alveolar ridge augmentation

    DEFF Research Database (Denmark)

    Pinholt, E M; Ruyter, I E; Haanaes, H R

    1992-01-01

    The purpose of this study was to evaluate four commercial apatite products. Subperiosteal alveolar ridge augmentation was performed on the maxilla of rats by implantation of granules of two dense products and of two porous products, and the tissue response was compared with the material character......The purpose of this study was to evaluate four commercial apatite products. Subperiosteal alveolar ridge augmentation was performed on the maxilla of rats by implantation of granules of two dense products and of two porous products, and the tissue response was compared with the material...

  13. Growth of apatite on chitosan-multiwall carbon nanotube composite membranes

    International Nuclear Information System (INIS)

    Yang Jun; Yao Zhiwen; Tang Changyu; Darvell, B.W.; Zhang Hualin; Pan Lingzhan; Liu Jingsong; Chen Zhiqing

    2009-01-01

    Bioactive membranes for guided tissue regeneration would be of value for periodontal therapy. Chitosan-multiwall carbon nanotube (CS-MWNT) composites were treated to deposit nanoscopic apatite for MWNT proportions of 0-4 mass%. Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, and X-ray diffraction were used for characterization. Apatite was formed on the CS-MWNT composites at low MWNT concentrations, but the dispersion of the MWNT affects the crystallite size and the Ca/P molar ratio of the composite. The smallest crystallite size was 9 nm at 1 mass% MWNT.

  14. Correlated prompt fission data in transport simulations

    Science.gov (United States)

    Talou, P.; Vogt, R.; Randrup, J.; Rising, M. E.; Pozzi, S. A.; Verbeke, J.; Andrews, M. T.; Clarke, S. D.; Jaffke, P.; Jandel, M.; Kawano, T.; Marcath, M. J.; Meierbachtol, K.; Nakae, L.; Rusev, G.; Sood, A.; Stetcu, I.; Walker, C.

    2018-01-01

    Detailed information on the fission process can be inferred from the observation, modeling and theoretical understanding of prompt fission neutron and γ-ray observables. Beyond simple average quantities, the study of distributions and correlations in prompt data, e.g., multiplicity-dependent neutron and γ-ray spectra, angular distributions of the emitted particles, n - n, n - γ, and γ - γ correlations, can place stringent constraints on fission models and parameters that would otherwise be free to be tuned separately to represent individual fission observables. The FREYA and CGMF codes have been developed to follow the sequential emissions of prompt neutrons and γ rays from the initial excited fission fragments produced right after scission. Both codes implement Monte Carlo techniques to sample initial fission fragment configurations in mass, charge and kinetic energy and sample probabilities of neutron and γ emission at each stage of the decay. This approach naturally leads to using simple but powerful statistical techniques to infer distributions and correlations among many observables and model parameters. The comparison of model calculations with experimental data provides a rich arena for testing various nuclear physics models such as those related to the nuclear structure and level densities of neutron-rich nuclei, the γ-ray strength functions of dipole and quadrupole transitions, the mechanism for dividing the excitation energy between the two nascent fragments near scission, and the mechanisms behind the production of angular momentum in the fragments, etc. Beyond the obvious interest from a fundamental physics point of view, such studies are also important for addressing data needs in various nuclear applications. The inclusion of the FREYA and CGMF codes into the MCNP6.2 and MCNPX - PoliMi transport codes, for instance, provides a new and powerful tool to simulate correlated fission events in neutron transport calculations important in

  15. Irradiation effects in fused quartz 'Suprasil' as a detector of fission fragments under high flux of reactor neutrons

    International Nuclear Information System (INIS)

    Moraes, O.M.G. de.

    1984-01-01

    A systematic study about the registration characteristics of synthetic fused quartz 'Suprasil I' use as a detector of fission fragments under high flux of reactor neutrons and the effects of irradiation on it was performed. Fission fragments of 252 Cf, gamma radiation doses of of 60 Co up to 150 MGy, and integrated neutrons fluxes up to 10 20 n/cm 2 were used. A model to explain the effects on track registration and development characteristics of 'Suprasil I' irradiated on reactors were proposed, based on the obtained results for efficiency an for annealing. (C.G.C.) [pt

  16. Simultaneous incorporation of carbonate and fluoride in synthetic apatites: Effect on crystallographic and physico-chemical properties.

    Science.gov (United States)

    Yao, Fang; LeGeros, John P; LeGeros, Racquel Z

    2009-07-01

    The mineral in bone is an impure hydroxyapatite, with carbonate as the chief minor substituent. Fluoride has been shown to stimulate osteoblastic activity and inhibit osteoclastic resorption in vitro. CO(3)- and F-substituted apatite (CFA) has been considered as potential bone graft material for orthopedic and dental applications. The objective of this study was to determine the effects of simultaneously incorporated CO(3) and F on the crystallographic physico-chemical properties of apatite. The results showed that increasing CO(3) and Na content in apatites with relatively constant F concentration caused a decrease in crystallite size and an increase in the extent of calcium release; increasing F content in apatites with relatively constant CO(3) concentration caused an increase in crystallite size and a decrease in the extent of Ca release. These findings suggest that CFAs as bone graft materials of desired solubility can be prepared by manipulating the relative concentrations of CO(3) and F incorporated in the apatite.

  17. Asymmetry in ternary fission induced by polarized neutrons and fission mechanism

    International Nuclear Information System (INIS)

    Bunakov, V.E.; Gennenvajn, F.; Dzhessinger, P.; Mutterer, M.; Petrov, G.A.

    2003-01-01

    The results of measuring the P-odd, P-even (right-left) and T-odd asymmetries of the charged particles emission in the double and ternary fission, induced by the polarized neutrons, are considered. It is shown, what kind of information on the mechanism of the ternary nuclear fission may be obtained from the theoretical analysis of these data [ru

  18. Fission-product yields for thermal-neutron fission of curium-243

    International Nuclear Information System (INIS)

    Breederland, D.G.

    1982-01-01

    Cumulative fission yields for 25 gamma rays emitted during the decay of 23 fission products produced by thermal-neutron fission of 243 Cm have been determined. Using Ge(Li) spectroscopy, 33 successive pulse-height spectra of gamma rays emitted from a 77-ng sample of 243 Cm over a period of approximately two and one-half months were analyzed. Reduction of these spectra resulted in the identification and matching of gamma-ray energies and half-lives to specific radionuclides. Using these results, 23 cumulative fission-product yields were calculated. Only those radionuclides having half-lives between 6 hours and 65 days were observed. Prior to this experiment, no fission-product yields had been recorded for 243 Cm

  19. Fission Surface Power Technology Development Update

    Science.gov (United States)

    Palac, Donald T.; Mason, Lee S.; Houts, Michael G.; Harlow, Scott

    2011-01-01

    Power is a critical consideration in planning exploration of the surfaces of the Moon, Mars, and places beyond. Nuclear power is an important option, especially for locations in the solar system where sunlight is limited or environmental conditions are challenging (e.g., extreme cold, dust storms). NASA and the Department of Energy are maintaining the option for fission surface power for the Moon and Mars by developing and demonstrating technology for a fission surface power system. The Fission Surface Power Systems project has focused on subscale component and subsystem demonstrations to address the feasibility of a low-risk, low-cost approach to space nuclear power for surface missions. Laboratory demonstrations of the liquid metal pump, reactor control drum drive, power conversion, heat rejection, and power management and distribution technologies have validated that the fundamental characteristics and performance of these components and subsystems are consistent with a Fission Surface Power preliminary reference concept. In addition, subscale versions of a non-nuclear reactor simulator, using electric resistance heating in place of the reactor fuel, have been built and operated with liquid metal sodium-potassium and helium/xenon gas heat transfer loops, demonstrating the viability of establishing system-level performance and characteristics of fission surface power technologies without requiring a nuclear reactor. While some component and subsystem testing will continue through 2011 and beyond, the results to date provide sufficient confidence to proceed with system level technology readiness demonstration. To demonstrate the system level readiness of fission surface power in an operationally relevant environment (the primary goal of the Fission Surface Power Systems project), a full scale, 1/4 power Technology Demonstration Unit (TDU) is under development. The TDU will consist of a non-nuclear reactor simulator, a sodium-potassium heat transfer loop, a power

  20. Rupture of the neck in nuclear fission

    International Nuclear Information System (INIS)

    Davies, K.T.R.; Managan, R.A.; Nix, J.R.; Sierk, A.J.

    1977-01-01

    We introduce a degree of freedom to describe the rupture of the neck in nuclear fission and calculate the point at which the neck ruptures as the nucleus descends dynamically from its fission saddle point. This is done by mentally slicing the system into two portions at its minimum neck radius and calculating the force required to separate the two portions while keeping their shapes fixed. This force is obtained by differentiating with respect to separation the sum of the Coulomb and nuclear interaction energies between the two portions. For nuclei throughout the Periodic Table we calculate this force along dynamical paths leading from the fission saddle point. The force is initially attractive but becomes repulsive when the neck reaches a critical size. For actinide nuclei the neck radius at which rupture occurs is about 2 fm. This increases the calculated translational kinetic energy of the fission fragments at infinity relative to that calculated for scission occurring at zero neck radius. With the effect of neck rupture taken into account, we calculate and compare with experimental results fission-fragment kinetic energies for two types of nuclear dissipation: ordinary two-body viscosity and one-body dissipation