John R. B. Lighton
- Published in print:
- 2008
- Published Online:
- September 2008
- ISBN:
- 9780195310610
- eISBN:
- 9780199871414
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195310610.003.0016
- Subject:
- Biology, Animal Biology, Biotechnology
Metabolic measurements are sensitive to the activity level of the animal being measured. This chapter describes the various technologies available for recording the activity level of a study organism ...
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Metabolic measurements are sensitive to the activity level of the animal being measured. This chapter describes the various technologies available for recording the activity level of a study organism in synchrony with metabolic data, usually obtained using a flow-through system. These technologies include optical activity detection, in which information is extracted from fluctuations in light intensity; video activity detection; magnetic activity detection; capacitive activity detection; passive far-infrared activity detection; mechanical activity detection, often using a center of gravity sensor below a cage or chamber; and microwave reflectance activity detection.Less
Metabolic measurements are sensitive to the activity level of the animal being measured. This chapter describes the various technologies available for recording the activity level of a study organism in synchrony with metabolic data, usually obtained using a flow-through system. These technologies include optical activity detection, in which information is extracted from fluctuations in light intensity; video activity detection; magnetic activity detection; capacitive activity detection; passive far-infrared activity detection; mechanical activity detection, often using a center of gravity sensor below a cage or chamber; and microwave reflectance activity detection.
Naomi E. Chayen, John R. Helliwell, and Edward H. Snell
- Published in print:
- 2010
- Published Online:
- May 2010
- ISBN:
- 9780199213252
- eISBN:
- 9780191707575
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199213252.003.0015
- Subject:
- Physics, Crystallography
Unusual diffraction geometries may seem a curiosity but may stimulate novel avenues of application. Not least they illustrate a diversity of diffraction‐measuring possibilities. Laue diffraction ...
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Unusual diffraction geometries may seem a curiosity but may stimulate novel avenues of application. Not least they illustrate a diversity of diffraction‐measuring possibilities. Laue diffraction including 3‐dimensional detector arrangements is described. The particular congestion of neutron Laue diffraction patterns with big crystals is highlighted. The large‐angle oscillation technique is discussed including the principle with the Ewald sphere construction and practical examples of ‘LOT’ diffraction patterns. Ultra‐fine‐phi‐slicing with perfect or near‐perfect crystals is described. Particular success has been obtained with Laue diffraction where applications to time‐resolved structural intermediates using synchrotron radiation as well as hydrogen and hydration in macromolecular structure are described.Less
Unusual diffraction geometries may seem a curiosity but may stimulate novel avenues of application. Not least they illustrate a diversity of diffraction‐measuring possibilities. Laue diffraction including 3‐dimensional detector arrangements is described. The particular congestion of neutron Laue diffraction patterns with big crystals is highlighted. The large‐angle oscillation technique is discussed including the principle with the Ewald sphere construction and practical examples of ‘LOT’ diffraction patterns. Ultra‐fine‐phi‐slicing with perfect or near‐perfect crystals is described. Particular success has been obtained with Laue diffraction where applications to time‐resolved structural intermediates using synchrotron radiation as well as hydrogen and hydration in macromolecular structure are described.
Michele Maggiore
- Published in print:
- 2007
- Published Online:
- January 2008
- ISBN:
- 9780198570745
- eISBN:
- 9780191717666
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198570745.001.0001
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
This book deals with all aspects of gravitational-wave physics, both theoretical and experimental. This first volume deals with gravitational wave (GW) theory and experiments. Part I discusses the ...
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This book deals with all aspects of gravitational-wave physics, both theoretical and experimental. This first volume deals with gravitational wave (GW) theory and experiments. Part I discusses the theory of GWs, re-deriving afresh and in a coherent way all the results presented. Both the geometrical and the field-theoretical approach to general relativity are discussed. The generation of GWs is discussed first in linearized theory (including the general multipole expansion) and then within the post-Newtonian formalism. Many important calculations (inspiral of compact binaries, GW emission by rotating or precessing bodies, infall into black holes, etc.) are presented. The observation of GWs emission from the change in the orbital period of binary pulsar, such as the Hulse-Taylor pulsar and the double pulsar, is also explained, and the pulsar timing formula is derived. Part II discusses the principles of GW experiments, going into the detail of the functioning of both interferometers and resonant-mass detectors. One chapter is devoted to the data analysis techniques relevant for GW experiments.Less
This book deals with all aspects of gravitational-wave physics, both theoretical and experimental. This first volume deals with gravitational wave (GW) theory and experiments. Part I discusses the theory of GWs, re-deriving afresh and in a coherent way all the results presented. Both the geometrical and the field-theoretical approach to general relativity are discussed. The generation of GWs is discussed first in linearized theory (including the general multipole expansion) and then within the post-Newtonian formalism. Many important calculations (inspiral of compact binaries, GW emission by rotating or precessing bodies, infall into black holes, etc.) are presented. The observation of GWs emission from the change in the orbital period of binary pulsar, such as the Hulse-Taylor pulsar and the double pulsar, is also explained, and the pulsar timing formula is derived. Part II discusses the principles of GW experiments, going into the detail of the functioning of both interferometers and resonant-mass detectors. One chapter is devoted to the data analysis techniques relevant for GW experiments.
Helmuth Spieler
- Published in print:
- 2005
- Published Online:
- September 2007
- ISBN:
- 9780198527848
- eISBN:
- 9780191713248
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198527848.001.0001
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
Semiconductor sensors patterned at the micron scale combined with custom-designed integrated circuits have revolutionized semiconductor radiation detector systems. Designs covering many square meters ...
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Semiconductor sensors patterned at the micron scale combined with custom-designed integrated circuits have revolutionized semiconductor radiation detector systems. Designs covering many square meters with millions of signal channels are now commonplace in high-energy physics and the technology is finding its way into many other fields, ranging from astrophysics to experiments at synchrotron light sources and medical imaging. This book presents a discussion of the many facets of highly integrated semiconductor detector systems, covering sensors, signal processing, transistors, circuits, low-noise electronics, and radiation effects. To lay a basis for the more detailed discussions in the book and aid in understanding how these different elements combine to form functional detector systems, the text includes introductions to semiconductor physics, diodes, detectors, signal formation, transistors, amplifier circuits, electronic noise mechanisms, and signal processing. A chapter on digital electronics includes key elements of analog-to-digital converters and an introduction to digital signal processing. The physics of radiation damage in semiconductor devices is discussed and applied to detectors and electronics. The diversity of design approaches is illustrated in a chapter describing systems in high-energy physics, astronomy, and astrophysics. Finally, a chapter ‘Why things don't work’, discusses common pitfalls, covering interference mechanisms such as power supply noise, microphonics, and shared current paths (‘ground loops’), together with mitigation techniques for pickup noise reduction, both at the circuit and system level. Beginning at a basic level, the book provides a unique introduction to a key area of modern science.Less
Semiconductor sensors patterned at the micron scale combined with custom-designed integrated circuits have revolutionized semiconductor radiation detector systems. Designs covering many square meters with millions of signal channels are now commonplace in high-energy physics and the technology is finding its way into many other fields, ranging from astrophysics to experiments at synchrotron light sources and medical imaging. This book presents a discussion of the many facets of highly integrated semiconductor detector systems, covering sensors, signal processing, transistors, circuits, low-noise electronics, and radiation effects. To lay a basis for the more detailed discussions in the book and aid in understanding how these different elements combine to form functional detector systems, the text includes introductions to semiconductor physics, diodes, detectors, signal formation, transistors, amplifier circuits, electronic noise mechanisms, and signal processing. A chapter on digital electronics includes key elements of analog-to-digital converters and an introduction to digital signal processing. The physics of radiation damage in semiconductor devices is discussed and applied to detectors and electronics. The diversity of design approaches is illustrated in a chapter describing systems in high-energy physics, astronomy, and astrophysics. Finally, a chapter ‘Why things don't work’, discusses common pitfalls, covering interference mechanisms such as power supply noise, microphonics, and shared current paths (‘ground loops’), together with mitigation techniques for pickup noise reduction, both at the circuit and system level. Beginning at a basic level, the book provides a unique introduction to a key area of modern science.
Sergey Ganichev and Willi Prettl
- Published in print:
- 2005
- Published Online:
- September 2007
- ISBN:
- 9780198528302
- eISBN:
- 9780191713637
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198528302.001.0001
- Subject:
- Physics, Condensed Matter Physics / Materials
This book presents high-power terahertz applications to semiconductors and semiconductor structures. It aims to bridge the gap between optics and microwave physics. It focuses on a core topic of ...
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This book presents high-power terahertz applications to semiconductors and semiconductor structures. It aims to bridge the gap between optics and microwave physics. It focuses on a core topic of semiconductor physics, providing a full description of the state of art of the field. The book introduces new physical phenomena which occur in the terahertz frequency range at the transition from semi-classical physics with a classical field amplitude to the fully quantized limit with photons. It covers tunneling in high-frequency fields, nonlinear absorption of radiation and radiation heating, nonlinear optics in the classical sense, Bloch-oscillations and ponderomotive forces of the terahertz radiation on free carriers, photon drag and photogalvanic effects, and terahertz spin dependent phenomena being of importance in the field of spintronics. Background information for future work and references of current literature are given. The book also discusses various experimental aspects like the generation of high-power coherent terahertz radiation, properties of materials with respect to their application in optical components, and detection schemes of short intense terahertz pulses.Less
This book presents high-power terahertz applications to semiconductors and semiconductor structures. It aims to bridge the gap between optics and microwave physics. It focuses on a core topic of semiconductor physics, providing a full description of the state of art of the field. The book introduces new physical phenomena which occur in the terahertz frequency range at the transition from semi-classical physics with a classical field amplitude to the fully quantized limit with photons. It covers tunneling in high-frequency fields, nonlinear absorption of radiation and radiation heating, nonlinear optics in the classical sense, Bloch-oscillations and ponderomotive forces of the terahertz radiation on free carriers, photon drag and photogalvanic effects, and terahertz spin dependent phenomena being of importance in the field of spintronics. Background information for future work and references of current literature are given. The book also discusses various experimental aspects like the generation of high-power coherent terahertz radiation, properties of materials with respect to their application in optical components, and detection schemes of short intense terahertz pulses.
Željko Ivezic, Andrew J. Connolly, Jacob T VanderPlas, and Alexander Gray
- Published in print:
- 2014
- Published Online:
- October 2017
- ISBN:
- 9780691151687
- eISBN:
- 9781400848911
- Item type:
- book
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691151687.001.0001
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
As telescopes, detectors, and computers grow ever more powerful, the volume of data at the disposal of astronomers and astrophysicists will enter the petabyte domain, providing accurate measurements ...
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As telescopes, detectors, and computers grow ever more powerful, the volume of data at the disposal of astronomers and astrophysicists will enter the petabyte domain, providing accurate measurements for billions of celestial objects. This book provides a comprehensive and accessible introduction to the cutting-edge statistical methods needed to efficiently analyze complex data sets from astronomical surveys such as the Panoramic Survey Telescope and Rapid Response System, the Dark Energy Survey, and the upcoming Large Synoptic Survey Telescope. It serves as a practical handbook for graduate students and advanced undergraduates in physics and astronomy, and as an indispensable reference for researchers. The book presents a wealth of practical analysis problems, evaluates techniques for solving them, and explains how to use various approaches for different types and sizes of data sets. For all applications described in the book, Python code and example data sets are provided. The supporting data sets have been carefully selected from contemporary astronomical surveys (for example, the Sloan Digital Sky Survey) and are easy to download and use. The accompanying Python code is publicly available, well documented, and follows uniform coding standards. Together, the data sets and code enable readers to reproduce all the figures and examples, evaluate the methods, and adapt them to their own fields of interest.Less
As telescopes, detectors, and computers grow ever more powerful, the volume of data at the disposal of astronomers and astrophysicists will enter the petabyte domain, providing accurate measurements for billions of celestial objects. This book provides a comprehensive and accessible introduction to the cutting-edge statistical methods needed to efficiently analyze complex data sets from astronomical surveys such as the Panoramic Survey Telescope and Rapid Response System, the Dark Energy Survey, and the upcoming Large Synoptic Survey Telescope. It serves as a practical handbook for graduate students and advanced undergraduates in physics and astronomy, and as an indispensable reference for researchers. The book presents a wealth of practical analysis problems, evaluates techniques for solving them, and explains how to use various approaches for different types and sizes of data sets. For all applications described in the book, Python code and example data sets are provided. The supporting data sets have been carefully selected from contemporary astronomical surveys (for example, the Sloan Digital Sky Survey) and are easy to download and use. The accompanying Python code is publicly available, well documented, and follows uniform coding standards. Together, the data sets and code enable readers to reproduce all the figures and examples, evaluate the methods, and adapt them to their own fields of interest.
Helmuth Spieler
- Published in print:
- 2005
- Published Online:
- September 2007
- ISBN:
- 9780198527848
- eISBN:
- 9780191713248
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198527848.003.0001
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
This chapter summarizes the contents of the subsequent chapters to provide a perspective before going into more detailed discussions. The basic functions of radiation detector systems are described. ...
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This chapter summarizes the contents of the subsequent chapters to provide a perspective before going into more detailed discussions. The basic functions of radiation detector systems are described. Constraints in electro-mechanical integration are illustrated, such as minimizing material in tracking detectors, which in turn drives the need for low power dissipation to reduce material in cabling and cooling systems. The chapter then moves on to overviews of semiconductor sensor physics and signal formation, energy and position resolution, sensor structures including strip and pixel devices, signal acquisition electronics, electronic noise, signal processing, and digitization. The final section illustrates how individual sensor channels are combined to form detector modules and how the signal readout is organized in large systems.Less
This chapter summarizes the contents of the subsequent chapters to provide a perspective before going into more detailed discussions. The basic functions of radiation detector systems are described. Constraints in electro-mechanical integration are illustrated, such as minimizing material in tracking detectors, which in turn drives the need for low power dissipation to reduce material in cabling and cooling systems. The chapter then moves on to overviews of semiconductor sensor physics and signal formation, energy and position resolution, sensor structures including strip and pixel devices, signal acquisition electronics, electronic noise, signal processing, and digitization. The final section illustrates how individual sensor channels are combined to form detector modules and how the signal readout is organized in large systems.
Helmuth Spieler
- Published in print:
- 2005
- Published Online:
- September 2007
- ISBN:
- 9780198527848
- eISBN:
- 9780191713248
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198527848.003.0008
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
This chapter discusses conflicts and compromises in detector systems and illustrates different design approaches in a variety of applications. After a discussion of general design considerations, ...
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This chapter discusses conflicts and compromises in detector systems and illustrates different design approaches in a variety of applications. After a discussion of general design considerations, examples of detector systems for e + e - colliders, hadron colliders, and astrophysics are described. Systems include strip detectors with CMOS and bipolar transistor front-ends utilizing both analog and binary readout. Constraints on long-strip detectors dominated by sensor noise are discussed. Non-projective two-dimensional position sensing is provided by pixel detectors utilizing CCDs and hybrid pixel devices, applied to both charged particle and photon imaging. Requirements at high luminosity colliders, such as the LHC, and techniques to cope with high rates and radiation damage while maintaining a practical power budget, are described. The chapter closes with a brief discussion of considerations in design, assembly, and testing.Less
This chapter discusses conflicts and compromises in detector systems and illustrates different design approaches in a variety of applications. After a discussion of general design considerations, examples of detector systems for e + e - colliders, hadron colliders, and astrophysics are described. Systems include strip detectors with CMOS and bipolar transistor front-ends utilizing both analog and binary readout. Constraints on long-strip detectors dominated by sensor noise are discussed. Non-projective two-dimensional position sensing is provided by pixel detectors utilizing CCDs and hybrid pixel devices, applied to both charged particle and photon imaging. Requirements at high luminosity colliders, such as the LHC, and techniques to cope with high rates and radiation damage while maintaining a practical power budget, are described. The chapter closes with a brief discussion of considerations in design, assembly, and testing.
R. Duncan Luce
- Published in print:
- 1991
- Published Online:
- January 2008
- ISBN:
- 9780195070019
- eISBN:
- 9780199869879
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195070019.003.0004
- Subject:
- Psychology, Cognitive Models and Architectures
This chapter discusses the distributions of simple decision latencies. Topics covered include empirical distributions; discrete-time, information-accumulation detectors; continuous-time, ...
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This chapter discusses the distributions of simple decision latencies. Topics covered include empirical distributions; discrete-time, information-accumulation detectors; continuous-time, information-accumulation detectors; and the race between level and change detectors.Less
This chapter discusses the distributions of simple decision latencies. Topics covered include empirical distributions; discrete-time, information-accumulation detectors; continuous-time, information-accumulation detectors; and the race between level and change detectors.
Charles D. Bailyn
- Published in print:
- 2014
- Published Online:
- October 2017
- ISBN:
- 9780691148823
- eISBN:
- 9781400850563
- Item type:
- chapter
- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691148823.003.0004
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
This chapter examines stellar-mass black holes. The empirical study of black holes began in the 1960s with the discovery of quasars and the advent of X-ray astronomy. X-ray detectors could detect ...
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This chapter examines stellar-mass black holes. The empirical study of black holes began in the 1960s with the discovery of quasars and the advent of X-ray astronomy. X-ray detectors could detect X-rays coming from a particular direction—as the instrument rotated, the detector scanned the sky. It was not expected that X-ray sources from outside the solar system would be detectable. However, it was quickly discovered that there were strong X-ray sources that appeared in the same position in every scan. The inferred luminosity of the sources was hundreds or thousands of times brighter than the Sun. When coincident optical stars were identified, they proved to be relatively faint. Thus, it was clear that a new class of celestial sources must exist whose radiation is predominantly in the form of X-rays, with a total luminosity comparable to or greater than that of ordinary stars.Less
This chapter examines stellar-mass black holes. The empirical study of black holes began in the 1960s with the discovery of quasars and the advent of X-ray astronomy. X-ray detectors could detect X-rays coming from a particular direction—as the instrument rotated, the detector scanned the sky. It was not expected that X-ray sources from outside the solar system would be detectable. However, it was quickly discovered that there were strong X-ray sources that appeared in the same position in every scan. The inferred luminosity of the sources was hundreds or thousands of times brighter than the Sun. When coincident optical stars were identified, they proved to be relatively faint. Thus, it was clear that a new class of celestial sources must exist whose radiation is predominantly in the form of X-rays, with a total luminosity comparable to or greater than that of ordinary stars.
Ian P. Howard and Brian J. Rogers
- Published in print:
- 2008
- Published Online:
- May 2009
- ISBN:
- 9780195367607
- eISBN:
- 9780199867264
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195367607.003.0006
- Subject:
- Psychology, Cognitive Neuroscience, Cognitive Psychology
This chapter reviews the physiology of processes devoted to the detection of binocular disparity. The discussions cover disparity detectors; disparity detectors in cats; disparity detectors in ...
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This chapter reviews the physiology of processes devoted to the detection of binocular disparity. The discussions cover disparity detectors; disparity detectors in cats; disparity detectors in primates; subcortical disparity-tuned cells; disparity-detector properties; coding higher-order disparities; visual evoked potentials (VEPs) and binocular vision; and models of disparity processing.Less
This chapter reviews the physiology of processes devoted to the detection of binocular disparity. The discussions cover disparity detectors; disparity detectors in cats; disparity detectors in primates; subcortical disparity-tuned cells; disparity-detector properties; coding higher-order disparities; visual evoked potentials (VEPs) and binocular vision; and models of disparity processing.
Norma van Surdam Graham
- Published in print:
- 1989
- Published Online:
- January 2008
- ISBN:
- 9780195051544
- eISBN:
- 9780199872183
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195051544.003.0012
- Subject:
- Psychology, Cognitive Neuroscience
This chapter summarizes available evidence from the four kinds of near-threshold analyzer-revealing experiments presented in previous chapters — adaptation, summation, uncertainty, and identification ...
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This chapter summarizes available evidence from the four kinds of near-threshold analyzer-revealing experiments presented in previous chapters — adaptation, summation, uncertainty, and identification — for each of the seventeen pattern-vision dimensions along which multiple analyzers might exist. The effects of several factors, like age of observer and psychophysical procedure are also described. For each dimension, the chapter asks whether multiple analyzers exist on that dimension, and if they do, asks further questions: what is the analyzers' bandwidth? Are their outputs labeled? Are their outputs probabilistically independent or correlated? Is there inhibition among them? Occasional references are given in the course of the summary, but the majority of the references are to be found in a list of references at the end of the chapter organized by the type of analyzer-revealing experiment and by the patterns dimensions studied.Less
This chapter summarizes available evidence from the four kinds of near-threshold analyzer-revealing experiments presented in previous chapters — adaptation, summation, uncertainty, and identification — for each of the seventeen pattern-vision dimensions along which multiple analyzers might exist. The effects of several factors, like age of observer and psychophysical procedure are also described. For each dimension, the chapter asks whether multiple analyzers exist on that dimension, and if they do, asks further questions: what is the analyzers' bandwidth? Are their outputs labeled? Are their outputs probabilistically independent or correlated? Is there inhibition among them? Occasional references are given in the course of the summary, but the majority of the references are to be found in a list of references at the end of the chapter organized by the type of analyzer-revealing experiment and by the patterns dimensions studied.
Ian P. Howard and Brian J. Rogers
- Published in print:
- 1996
- Published Online:
- January 2008
- ISBN:
- 9780195084764
- eISBN:
- 9780199871049
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195084764.003.0004
- Subject:
- Psychology, Cognitive Psychology
This chapter begins with a discussion of the eye and visual pathways, the visual cortex, and midline interactions. It then covers disparity detectors, disparity tuning functions, types of disparity ...
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This chapter begins with a discussion of the eye and visual pathways, the visual cortex, and midline interactions. It then covers disparity detectors, disparity tuning functions, types of disparity coding, disparity coding in parvo- and magnocellular channels, and visual evoked potentials (VEPs).Less
This chapter begins with a discussion of the eye and visual pathways, the visual cortex, and midline interactions. It then covers disparity detectors, disparity tuning functions, types of disparity coding, disparity coding in parvo- and magnocellular channels, and visual evoked potentials (VEPs).
Alexander Blake
- Published in print:
- 2009
- Published Online:
- September 2009
- ISBN:
- 9780199219469
- eISBN:
- 9780191722516
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199219469.003.0006
- Subject:
- Physics, Crystallography
This chapter analyzes the collection of data on a modern area-detector diffractometer, with respect to the contributory factors: characteristics of the X-ray detector, choice of radiation appropriate ...
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This chapter analyzes the collection of data on a modern area-detector diffractometer, with respect to the contributory factors: characteristics of the X-ray detector, choice of radiation appropriate to the sample, temperature, pressure, and other conditions. The various kinds of detector system are reviewed, with their advantages and disadvantages, and CCD (charge-coupled device) detectors are described in more detail, including the necessary corrections for spatial and intensity distortions and background dark current effects. Methods of screening samples with X-rays are described, and consideration given to practical aspects of obtaining unit cell and orientation information, with advice for difficult cases. Data collection parameters and characteristics affecting speed and quality include the general level of diffraction intensity, crystal mosaicity, symmetry, and the use of low-temperature devices.Less
This chapter analyzes the collection of data on a modern area-detector diffractometer, with respect to the contributory factors: characteristics of the X-ray detector, choice of radiation appropriate to the sample, temperature, pressure, and other conditions. The various kinds of detector system are reviewed, with their advantages and disadvantages, and CCD (charge-coupled device) detectors are described in more detail, including the necessary corrections for spatial and intensity distortions and background dark current effects. Methods of screening samples with X-rays are described, and consideration given to practical aspects of obtaining unit cell and orientation information, with advice for difficult cases. Data collection parameters and characteristics affecting speed and quality include the general level of diffraction intensity, crystal mosaicity, symmetry, and the use of low-temperature devices.
I. M. Vardavas and F. W. Taylor
- Published in print:
- 2007
- Published Online:
- January 2008
- ISBN:
- 9780199227471
- eISBN:
- 9780191711138
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199227471.003.0009
- Subject:
- Physics, Geophysics, Atmospheric and Environmental Physics
Radiation measurements from the surface, inside the atmosphere, and from satellites are essential for understanding the climate and monitoring its behaviour. The principles of such measurements are ...
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Radiation measurements from the surface, inside the atmosphere, and from satellites are essential for understanding the climate and monitoring its behaviour. The principles of such measurements are discussed, including the choice of different detectors and other key components, system cooling, and observational details. The basis for calculations of the expected performance parameters, such as signal-to-noise ratio and minimum detectable temperature change, is developed and system trade-offs discussed.Less
Radiation measurements from the surface, inside the atmosphere, and from satellites are essential for understanding the climate and monitoring its behaviour. The principles of such measurements are discussed, including the choice of different detectors and other key components, system cooling, and observational details. The basis for calculations of the expected performance parameters, such as signal-to-noise ratio and minimum detectable temperature change, is developed and system trade-offs discussed.
GÜNTHER DISSERTORI, IAN G. KNOWLES, and MICHAEL SCHMELLING
- Published in print:
- 2009
- Published Online:
- January 2010
- ISBN:
- 9780199566419
- eISBN:
- 9780191708060
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199566419.003.0005
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology
Particle physics at high energies would be impossible without powerful accelerators and high-resolution detectors. This chapter discusses the basic technological and physical principles used for ...
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Particle physics at high energies would be impossible without powerful accelerators and high-resolution detectors. This chapter discusses the basic technological and physical principles used for those devices. The LEP electron-positron collider is used to illustrate the issues pertaining to large particle accelerators. After introducing the physics of particle detectors, the specific example of the ALEPH detector is presented.Less
Particle physics at high energies would be impossible without powerful accelerators and high-resolution detectors. This chapter discusses the basic technological and physical principles used for those devices. The LEP electron-positron collider is used to illustrate the issues pertaining to large particle accelerators. After introducing the physics of particle detectors, the specific example of the ALEPH detector is presented.
Heinz Graafsma and Thierry Martin
- Published in print:
- 2008
- Published Online:
- May 2008
- ISBN:
- 9780199213245
- eISBN:
- 9780191707582
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199213245.003.0010
- Subject:
- Physics, Condensed Matter Physics / Materials
Efforts are underway to optimize two-dimensional X-ray detectors, which have become a standard at synchrotron sources for practically all applications including tomography. Area detectors can be ...
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Efforts are underway to optimize two-dimensional X-ray detectors, which have become a standard at synchrotron sources for practically all applications including tomography. Area detectors can be divided into two main classes: in direct detection the X-ray photons are directly converted to an electrical signal via electron-hole pair creation, either in a semiconductor or in a gas; in indirect detection the X-ray photons are first converted into visible light that is subsequently converted to an electronic signal in the semiconductor. So far, the most effective, low-cost and low-risk solution for tomography has been indirect detection, where a scintillator converter screen is optically coupled to an integrating detector, either a commercial CCD camera, or a specially developed amorphous photodiode array. This chapter explains this technology and discusses the various components. It begins with a survey of the various existing types of X-ray conversion screens. This is followed by a discussion of the optical relays and the light sensors required to convert the light into a digital image.Less
Efforts are underway to optimize two-dimensional X-ray detectors, which have become a standard at synchrotron sources for practically all applications including tomography. Area detectors can be divided into two main classes: in direct detection the X-ray photons are directly converted to an electrical signal via electron-hole pair creation, either in a semiconductor or in a gas; in indirect detection the X-ray photons are first converted into visible light that is subsequently converted to an electronic signal in the semiconductor. So far, the most effective, low-cost and low-risk solution for tomography has been indirect detection, where a scintillator converter screen is optically coupled to an integrating detector, either a commercial CCD camera, or a specially developed amorphous photodiode array. This chapter explains this technology and discusses the various components. It begins with a survey of the various existing types of X-ray conversion screens. This is followed by a discussion of the optical relays and the light sensors required to convert the light into a digital image.
Erich H. Kisi and Christopher J. Howard
- Published in print:
- 2008
- Published Online:
- January 2009
- ISBN:
- 9780198515944
- eISBN:
- 9780191705663
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198515944.003.0003
- Subject:
- Physics, Condensed Matter Physics / Materials
This chapter first gives the location of facilities for neutron powder diffraction. Constant wavelength (CW) and time-of-flight (TOF) diffractometers are introduced. The typical components ...
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This chapter first gives the location of facilities for neutron powder diffraction. Constant wavelength (CW) and time-of-flight (TOF) diffractometers are introduced. The typical components (monochromators, collimators, neutron detectors) are described in some detail and a comparison of CW with TOF instruments is presented. The chapter includes advice on planning and executing measurements by neutron powder diffraction, as well as detail on the important matter of sample environment, that is, the furnaces, cryostats, pressure cells, electrochemical cells, etc., that the experiments might involve. Sample preparation is also a matter that demands quite careful attention, so important considerations are presented.Less
This chapter first gives the location of facilities for neutron powder diffraction. Constant wavelength (CW) and time-of-flight (TOF) diffractometers are introduced. The typical components (monochromators, collimators, neutron detectors) are described in some detail and a comparison of CW with TOF instruments is presented. The chapter includes advice on planning and executing measurements by neutron powder diffraction, as well as detail on the important matter of sample environment, that is, the furnaces, cryostats, pressure cells, electrochemical cells, etc., that the experiments might involve. Sample preparation is also a matter that demands quite careful attention, so important considerations are presented.
Ian P. Howard and Brian J. Rogers
- Published in print:
- 2012
- Published Online:
- May 2012
- ISBN:
- 9780199764150
- eISBN:
- 9780199949366
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199764150.003.0008
- Subject:
- Psychology, Vision, Cognitive Psychology
Stereoscopic vision involves detection of the 3-D structure of stimuli from differences between the images in the two eyes. This chapter reviews what is known about the physiology of these detectors ...
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Stereoscopic vision involves detection of the 3-D structure of stimuli from differences between the images in the two eyes. This chapter reviews what is known about the physiology of these detectors in cats and primates. Disparity detectors in the primary visual cortex code simple local disparities. Disparity detectors in the dorsal and the ventral streams of cortical processing are responsible for detecting disparity gradients, higher order patterns of disparity, and the joint coding of disparity and motion. Experiments are reviewed that used PET scan and fMRI to locate brain centers involved in detection of disparity. The chapter ends with a review of theoretical models of stereoscopic vision.Less
Stereoscopic vision involves detection of the 3-D structure of stimuli from differences between the images in the two eyes. This chapter reviews what is known about the physiology of these detectors in cats and primates. Disparity detectors in the primary visual cortex code simple local disparities. Disparity detectors in the dorsal and the ventral streams of cortical processing are responsible for detecting disparity gradients, higher order patterns of disparity, and the joint coding of disparity and motion. Experiments are reviewed that used PET scan and fMRI to locate brain centers involved in detection of disparity. The chapter ends with a review of theoretical models of stereoscopic vision.
Ivan Pelant and Jan Valenta
- Published in print:
- 2012
- Published Online:
- May 2012
- ISBN:
- 9780199588336
- eISBN:
- 9780191738548
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780199588336.003.0002
- Subject:
- Physics, Atomic, Laser, and Optical Physics
Experimental techniques of luminescence spectroscopy take into consideration specific features of the field: very low level of the detected light and requirement of not-extremely high spectral ...
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Experimental techniques of luminescence spectroscopy take into consideration specific features of the field: very low level of the detected light and requirement of not-extremely high spectral resolution. Physical principles and modes of operation of photon detectors used in luminescence spectroscopy are discussed (photomultiplier tubes, avalanche photodiodes and CCD detectors). Basic constructions of spectral devices (monochromators and spectrographs) and their important parameters (dispersion, resolving power, and throughput) are introduced and analyzed. Two signal detection methods are described: phase-synchronous (lock-in) technique and photon counting. Experimental conditions imposed to acquire spectra with high signal-to-noise ratio are examined. Corrections to be applied to spectra owing to spectral sensitivity of the detection channel and monochromator slits opening are considered. Finally, methods and apparatus for time‐resolved luminescence measurements are introduced (the phase-shift method, time‐correlated photon counting, and boxcar integrator). The exposition throughout the chapter is illustrated by selected examples of experimental curves.Less
Experimental techniques of luminescence spectroscopy take into consideration specific features of the field: very low level of the detected light and requirement of not-extremely high spectral resolution. Physical principles and modes of operation of photon detectors used in luminescence spectroscopy are discussed (photomultiplier tubes, avalanche photodiodes and CCD detectors). Basic constructions of spectral devices (monochromators and spectrographs) and their important parameters (dispersion, resolving power, and throughput) are introduced and analyzed. Two signal detection methods are described: phase-synchronous (lock-in) technique and photon counting. Experimental conditions imposed to acquire spectra with high signal-to-noise ratio are examined. Corrections to be applied to spectra owing to spectral sensitivity of the detection channel and monochromator slits opening are considered. Finally, methods and apparatus for time‐resolved luminescence measurements are introduced (the phase-shift method, time‐correlated photon counting, and boxcar integrator). The exposition throughout the chapter is illustrated by selected examples of experimental curves.
