Deposit characterization based on pulsed neutron induced borehole n-/γ-spectroscopy

Die gepulste Neutronenbohrlochmessung ist in der Kohlenwasserstoffindustrie eine etablierte Methode zur Reservoircharakterisierung. Die konservative Bergbauindustrie hat in der Vergangenheit gezögert, sie für die Lagerstättencharakterisierung einzusetzen, da es an schlanken Bohrlochsonden und verwertbaren Ergebnissen mangelte. Die petrophysikalische und geochemische Lagerstättencharakterisierung mittels der gepulsten neutroneninduzierten Bohrloch n-/-Spektroskopie mit einer neu entwickelten Bohrlochsonde (d = 76 mm; l = 3 m; m = 33 kg) namens OreLog zur Bestimmung der Elementzusammensetzung von Erzlagerstätten ist Ziel dieser Dissertation. Es wurden umfangreiche Labortests durchgeführt, um geeignete n- und -Detektoren, deren ideale Betriebsbedingungen und geometrische Anordnung innerhalb der Sonde zu bestimmen. Die Entwicklung wurde durch Monte-Carlo-Simulationen des N-Teilchen-Transportcodes (MCNP) unterstützt, um die Detektoreigenschaften zu bestimmen und Algorithmen für die Elementanalytik abzuleiten, indem die Sonde von verschiedenen Materialien umgeben wurde. Nachdem die grundlegenden Sondeneinstellungen definiert waren, wurden Feldtests in zwei gut erkundeten australischen Lagerstätten durchgeführt: Kanal- und Bändereisenerzlagerstätten im Pilbara, die hauptsächlich sedimentäre und metamorphe Lithologien vorweisen, und die aktive Beverley-Mine mit umgebenen Lagerstätten, die sedimentäre, metamorphe und magmatische Lithologien beinhalten. Es wurden sowohl geochemische als auch petrophysikalische Analysen an Bohrkernen und -klein zusammengestellt, sowie von Pumpversuchen abgeleitete hydrogeologische Daten der Beverley Lagerstätten. Detaillierte Bohrkerndokumentationen einschließlich dedizierter Laboruntersuchungen wurden durchgeführt. Die OreLog-Algorithmen wurden anhand von MCNP-Simulationen gängiger Lagerstättenzusammensetzungen und gut charakterisierter Bohrlöcher kalibriert. Dutzende von trockenen und wassergefüllten Bohrlöchern wurden geloggt und die Ergebnisse mit Laboranalysen verglichen. Die gewonnenen zeitaufgelösten Neutronenverteilungen und - Spektren wurden durch Template-Matching für die Elementzusammensetzung und die Ableitung petrophysikalischer Parameter entfaltet. Die Ergebnisse der untersuchten Lagerstätten zeigen eine Neutronenpenetrationstiefe von bis zu 1 m Durchmesser im Vergleich zu punktuellen Bohrkerndaten, eine starke Elementkorrelation von Fe, Si, Al, Ca, Cl, und niedrige Nachweisgrenzen. Ti, K, Mn, C, H, Mg sind (semi-)quantitativ nachweisbar. Petrophysikalische Größen wie Dichte und Porosität werden von der Bohrlochsonde adäquat geschätzt, wohingegen Permeabilitätsschätzungen weder auf Bohrkerngröße noch auf regionaler Skala korreliert sind. Die Echtzeit-Elementmessung in HQ-Bohrungen (≥ 96 mm) wurde validiert. Einschränkungen gelten für petrophysikalische Größen, die durch NMR Bohrlochsonden realistischer bestimmt werden. Der Einsatz der Sonde in wirtschaftlich relevanten Eisenerzlagerstätten zur Echtzeitbestimmung der Erzgehalte („Grade Control“) im Bohrloch wurde validiert. Geringfügige technische Verbesserungen und die Erweiterung der Kalibriergrößen zusammen mit einem variablen Neutronenpuls-Regime könnten die Genauigkeit und die Auswahl der messbaren Elemente weiter erhöhen.Pulsed neutron borehole logging is an established method in the hydrocarbon industry for reservoir characterization. The conservative mining industry historically has been reluctant in implementing it for deposit characterization due to a lack of slim sized logging tools and appropriate results. The need for petrophysical and geochemical deposit characterization based on pulsed neutron induced borehole n-/-spectroscopy was addressed in this thesis with a newly developed logging tool (d = 76 mm; l = 3 m; m = 33 kg) called OreLog suitable for elemental logging of ore deposits. Extensive laboratory test work was realized to determine the appropriate n- and -detectors, their operational conditions and physical location within the tool to meet this goal. The development was supported by Monte Carlo N-Particle transport code (MCNP) simulations to determine the behavior of the detectors and deduce elemental logging algorithms by surrounding the tool with different materials. Once the basic tool settings have been determined, field tests in two well explored Australian deposits were carried out: Channel iron deposits in the Pilbara exposing mainly sedimentary and metamorphic rocks and the operating Beverley mine with nearby deposits exposing sedimentary, metamorphic, and igneous rocks. Both geochemical and petrophysical assays from drill core samples and cuttings were collected besides hydrogeological data derived from pump tests at the Beverley deposits. Detailed core logs were compiled including laboratory assays where available. OreLog algorithms were calibrated based on MCNP simulations of common deposit scenarios and well characterized boreholes. Dozens of dry and waterfilled boreholes were logged and the output data was compared to laboratory data. The acquired n-distributions and γ-spectra were processed by template matching for elemental logging and estimation of petrophysical parameters. The results of the investigated deposits show a neutron penetration diameter up to 1 m around the borehole compared to punctual core data, a strong correlation with Fe, Si, Al, Ca, Cl, and low detection limits. Ti, K, Mn, C, H, Mg are detectable (semi- )quantitatively. Petrophysical quantities like density and porosity are estimated adequately, whereas permeability estimations in variable lithologies are not correlated, neither on core nor regional scale. Real-time elemental logging in HQ (≥ 96 mm) boreholes has been validated, especially for economically relevant iron ore deposits. Limitations apply to petrophysical quantities which are more realistically determined by NMR borehole tools. Some further technical improvements and enhancement of calibration parameters alongside a variable neutron pulsing regime could further increase the accuracy and suite of detectable elements

Annual Report 2005 - Institute of Nuclear and Hadron Physics

Preface The Forschungszentrum Rossendorf (FZR) at Dresden is a multidisciplinary research center within the Wissenschafts-Gemeinschaft G. W. Leibniz (WGL), one of the German agencies for extra-university research. The center is active in investigations on the structure of matter as well as in the life sciences and in environmental research. The Institute of Nuclear and Hadron Physics (IKH) within the FZR avails for its research the coupling of radiation to matter in subatomic dimensions as well as to tissue, to cells, and to their components. Its research in the field of Subatomic Physics is part of the FZR-program Structure of Matter and its investigations concerning the interaction of Biostructures and Radiation contribute to the bf Life Science program of the FZR. In this field the IKH exploits possibilities for transfer and introduction of experimental and theoretical techniques from particle and nuclear physics to projects in radiobiology and biophysics. Much of this kind of interdisciplinary transfer is connected to the Radiation Source ELBE at the FZR. With its superconducting accelerator for relativistic electrons this large installation provides photons in the wide wavelength range from fm to mm - i.e. bremsstrahlung for the investigation of photonuclear processes, hard X-rays for radiobiological and other studies and infrared light for research on the structural dynamics of biomolecules. The investigation of radiation-induced processes not only dominates the projects in nuclear astrophysics as pursued at ELBE, it also is a central theme of the experimental and theoretical research performed by the IKH in close connection to the heavy ion synchrotron SIS and the upcoming FAIR facility at Darmstadt. ELBE also will deliver compact bunches of secondary neutrons and fission fragments; both offer new possibilities in laboratory studies related to the cosmic breeding of the chemical elements thus complementing the astrophysics-motivated studies with bremsstrahlung photons..

Technical Design Report for PANDA Electromagnetic Calorimeter (EMC)

This document presents the technical layout and the envisaged performance of the Electromagnetic Calorimeter (EMC) for the PANDA target spectrometer. The EMC has been designed to meet the physics goals of the PANDA experiment. The performance figures are based on extensive prototype tests and radiation hardness studies. The document shows that the EMC is ready for construction up to the front-end electronics interface

Development of fast and radiation hard Monolithic Active Pixel Sensors (MAPS) optimized for open charm meson detection with the CBM - vertex detector

The work presented in this thesis addresses a key issue of the CBM experiment at FAIR, which aims to study charm production in heavy ion collisions at energies ranging from 10 to 40 AGeV . For the first time in this kinematical range, open charm mesons will be used as a probe of the nuclear fireball. Despite of their short decay length, which is typically in the order of few 100 µm in the laboratory frame, those mesons will be identified by reconstructing their decay vertex