Journal articles on the topic 'High resolution spectroscopy – Instruments – Design and construction'

Combining of the high spatial resolution of a Scanning Transmission Electron Microscope and the wealth of information from the secondary electrons and Auger spectra opens up new possibilities for materials research. In a prototype instrument at the Delft University of Technology we have shown that it is possible from the optical point of view to combine STEM and Auger spectroscopy [1]. With an Electron Energy Loss Spectrometer attached to the microscope it also became possible to perform coincidence measurements between the secondary electron signal and the EELS signal. We measured Auger spectra of carbon aluminium and Argon gas showing energy resolutions better than 1eV [2]. The coincidence measurements on carbon with a time resolution of 5 ns yielded basic insight in secondary electron emission processes [3]. However, for serious Auger spectroscopy, the specimen needs to be in Ultra High Vacuum. ( 10−10 Torr ). At this moment a new setup is in its last phase of construction.

AbstractSPECTRUM-RÖNTGEN-GAMMA (SRG) is one of a new series of large astronomical missions being planned by the Soviet Union and is scheduled for launch in mid-1993. The Space Research Institute (IKI) of the Academy of Sciences of the USSR and the Babakin Center (BC) are responsible for the scientific supervision and spacecraft construction, respectively. Mission objectives include broad and narrow band imaging spectroscopy over a wide range of energies from EUV through gamma rays with particular emphasis on extragalactic objects. The design of the Soviet Danish Röntgen Telescope (SODART) consists of two thin foil, conical shell approximations to Wolter 1 geometry. The reflectors are rolled aluminum foils which have been dipped in acrylic lacquer and coated with gold resulting in a super smooth surface. Each telescope has an aperture of 60 cm, a focal length of 8 m, a field of view of 1 deg and is designed to have a halfpower width of ≤2 arcmin. The conical geometry contributes 15 arcsec and manufacturing tolerances in the support structure and the quality of the figure of the foil the rest. The contribution from X-ray scattering is insignificant. Focal plane slides can position one of four instruments at the focus of each telescope. Images and spectra will be recorded with position sensitive proportional counters with spectral resolution as good as 13% at 6 keV. Spectral resolution of 2.5% at 6 keV is provided by an array of 19 cooled silicon detectors. A broad band polarimeter will be sensitive to residual polarization as low as 1%. An objective Bragg crystal panel, placed in front of one of the telescopes, will be capable of high resolution spectroscopic studies ((E/ΔE)) ~1000) of point- and extended sources.

The period covered by this report has seen significant progress in the development of the new generation of telescopes with apertures in the 8 m plus range. The period has encompassed the major construction phase of the 10 m Keck Telescope, witnessed the commissioning of the European Southern Observatory’s (ESO) New Technology Telescope and the approval of funding for the ESO Very Large Telescope (VLT). Significant progress has been achieved in developing the necessary technology for manufacturing and figuring large mirrors. There have been major expansions of activity in the areas of active control of telescope optics and adaptive optics, and in high angular resolution interferometry with several new groups entering both fields. The use of optical fibers, particularly in the area of multiple-object spectroscopy, has continued to grow. Several telescopes can now be operated remotely and the control systems of new telescopes are being designed to facilitate remote operation.

AbstractThe 4m Advance Technology Solar Telescope (ATST) is under construction on Maui, HI. With its unprecedented resolution and photon collecting power ATST will be an ideal tool for studying prominences and filaments and their role in producing Coronal Mass Ejections that drive Space Weather. The ATST facility will provide a set of first light instruments that enable imaging and spectroscopy of the dynamic filament and prominence structure at 8 times the resolution of Hinode. Polarimeters allow high precision chromospheric and coronal magnetometry at visible and infrared (IR) wavelengths. This paper summarizes the capabilities of the ATST first-light instrumentation with focus on prominence and filament science.

Secondary electrons form the main signal in a standard SEM, and machines incorporating Auger electron spectroscopy and imaging have become widely commercialized. However, these approaches to low energy (0-2000eV) electron spectroscopy and imaging do not work at the highest spatial resolution, since there are geometrical and electromagnetic conflicts as the focal length of the probe forming lens is reduced. As discussed elsewhere in more detail, the solution is to make the magnetic probe forming lens of the SEM/STEM also function as the first stage of the electron collection and analysis system.A new lOOkV field emission STEM has been constructed for the NSF HREM facility, which incorporates provision for using these low energy electrons from both sides of a thin sample. The outline design has been described previously. The microscope, codenamed MIDAS, is of UHV construction throughout with ∽10−10 mbar at the sample position, and extensive surface preparation facilities. The region of the column concerned with secondary and Auger electrons is shown diagrammatically, but to scale, in fig. 1. This region consists of the objective lens, O, bounded by analyser chambers AC1 and AC2, onto which the electron detectors are mounted.

NASA’s suborbital program provides an opportunity to conduct unique science experiments above Earth’s atmosphere and is a pipeline for the technology and personnel essential to future space astrophysics, heliophysics, and atmospheric science missions. In this paper, we describe three astronomy payloads developed (or in development) by the Ultraviolet Rocket Group at the University of Colorado. These far-ultraviolet (UV) (100–160[Formula: see text]nm) spectrographic instruments are used to study a range of scientific topics, from gas in the interstellar medium (accessing diagnostics of material spanning five orders of magnitude in temperature in a single observation) to the energetic radiation environment of nearby exoplanetary systems. The three instruments, Suborbital Local Interstellar Cloud Experiment (SLICE), Colorado High-resolution Echelle Stellar Spectrograph (CHESS), and Suborbital Imaging Spectrograph for Transition region Irradiance from Nearby Exoplanet host stars (SISTINE) form a progression of instrument designs and component-level technology maturation. SLICE is a pathfinder instrument for the development of new data handling, storage, and telemetry techniques. CHESS and SISTINE are testbeds for technology and instrument design enabling high-resolution ([Formula: see text]) point source spectroscopy and high throughput imaging spectroscopy, respectively, in support of future Explorer, Probe, and Flagship-class missions. The CHESS and SISTINE payloads support the development and flight testing of large-format photon-counting detectors and advanced optical coatings: NASA’s top two technology priorities for enabling a future flagship observatory (e.g. the LUVOIR Surveyor concept) that offers factors of [Formula: see text][Formula: see text]50–100 gain in UV spectroscopy capability over the Hubble Space Telescope. We present the design, component level laboratory characterization, and flight results for these instruments.

We developed a simple, cost-effective smartphone microscopy platform for use in educational and public engagement programs. We demonstrated its effectiveness, and potential for citizen science through a national imaging initiative, EnLightenment. The cost effectiveness of the instrument allowed for the program to deliver over 500 microscopes to more than 100 secondary schools throughout Scotland, targeting 1000’s of 12-14 year olds. Through careful, quantified, selection of a high power, low-cost objective lens, our smartphone microscope has an imaging resolution of microns, with a working distance of 3 mm. It is therefore capable of imaging single cells and sub-cellular features, and retains usability for young children. The microscopes were designed in kit form and provided an interdisciplinary educational tool. By providing full lesson plans and support material, we developed a framework to explore optical design, microscope performance, engineering challenges on construction and real-world applications in life sciences, biological imaging, marine biology, art, and technology. A national online imaging competition framed EnLightenment; with over 500 high quality images submitted of diverse content, spanning multiple disciplines. With examples of cellular and sub-cellular features clearly identifiable in some submissions, we show how young public can use these instruments for research-level imaging applications, and the potential of the instrument for citizen science programs.

We developed a simple, cost-effective smartphone microscopy platform for use in educational and public engagement programs. We demonstrated its effectiveness, and potential for citizen science through a national imaging initiative, EnLightenment. The cost effectiveness of the instrument allowed for the program to deliver over 500 microscopes to more than 100 secondary schools throughout Scotland, targeting 1000’s of 12-14 year olds. Through careful, quantified, selection of a high power, low-cost objective lens, our smartphone microscope has an imaging resolution of microns, with a working distance of 3 mm. It is therefore capable of imaging single cells and sub-cellular features, and retains usability for young children. The microscopes were designed in kit form and provided an interdisciplinary educational tool. By providing full lesson plans and support material, we developed a framework to explore optical design, microscope performance, engineering challenges on construction and real-world applications in life sciences, biological imaging, marine biology, art, and technology. A national online imaging competition framed EnLightenment; with over 500 high quality images submitted of diverse content, spanning multiple disciplines. With examples of cellular and sub-cellular features clearly identifiable in some submissions, we show how young public can use these instruments for research-level imaging applications, and the potential of the instrument for citizen science programs.

The Keck II Deep Imaging Multi-Object Spectrograph (DEIMOS) is a general purpose, faint object, multi-slit, double-beam spectrograph which offers wide spectral coverage, high spectral resolution, high throughput, and long slit length on the sky. This powerful instrument will be the principal optical spectrograph on the Keck II telescope. DEIMOS is optimized for faint-object spectroscopy of individual point sources, low-surface-brightness extended objects, or widely distributed samples of faint objects on the sky. To obtain high resolution (∼ 1 å) and wide spectral coverage (up to 5000 å) the spectrograph uses wide angle cameras and large CCD detectors with many pixels.This paper describes some of the work being carried out to obtain the CCD detectors required for the DEIMOS spectrograph. In addition, results are presented on the fabrication and characterization of a 4k × 2k three-side buttable CCD produced by Orbit Semiconductor, a silicon foundry in San Jose, California. This CCD was fabricated to test the ability of Orbit to produce high quality scientific CCDs with the characteristics required for detectors to be used in DEIMOS and other optical instruments of the Keck Observatory.

The beamline design, microscope specifications, and initial results from the new mid-infrared beamline (IRENI) are reviewed. Synchrotron-based spectrochemical imaging, as recently implemented at the Synchrotron Radiation Center in Stoughton, Wisconsin, demonstrates the new capability to achieve diffraction limited chemical imaging across the entire mid-infrared region, simultaneously, with high signal-to-noise ratio. IRENI extracts a large swath of radiation (320 hor. × 25 vert. mrads 2 ) to homogeneously illuminate a commercial infrared (IR) microscope equipped with an IR focal plane array (FPA) detector. Wide-field images are collected, in contrast to single-pixel imaging from the confocal geometry with raster scanning, commonly used at most synchrotron beamlines. IRENI rapidly generates high quality, high spatial resolution data. The relevant advantages (spatial oversampling, speed, sensitivity, and signal-to-noise ratio) are discussed in detail and demonstrated with examples from a variety of disciplines, including formalin-fixed and flash-frozen tissue samples, live cells, fixed cells, paint cross-sections, polymer fibers, and novel nanomaterials. The impact of Mie scattering corrections on this high quality data is shown, and first results with a grazing angle objective are presented, along with future enhancements and plans for implementation of similar, small-scale instruments.

Many scientific programs, most of them linked to stellar physics (such as asteroseismology, stellar rotational modulation, surface structures, Doppler imaging, Zeeman-Doppler imaging, variable stellar winds) require a continuous spectroscopic coverage during several days.MUSICOS (for MUlti-SIte COntinuous Spectroscopy) is an international project for setting up a network of high resolution spectrometers coupled to telescopes of the 2m class, well distributed around the world, and partly dedicated to continuous spectroscopy.The strategy to reach this objective was defined during two workshops organized at Paris-Meudon Observatory in 1988 and 1990, and consists of three steps: 1) organize multi-site spectroscopie campaigns using resident instruments on various telescopes around the world and transportable fiber-fed spectrographs where adequate spectroscopie equipment is not available; 2) design and develop a cross-dispersed echelle spectrograph, well suited for the scientific programs that require multi-site observations; 3) propose this MUSICOS spectrograph for duplication at several collaborating sites.

Abstract. A breadboard demonstrator of a novel UV/VIS grating spectrometer has been developed based upon a concentric arrangement of a spherical meniscus lens, concave spherical mirror and curved diffraction grating suitable for a range of atmospheric remote sensing applications from the ground or space. The spectrometer is compact and provides high optical efficiency and performance benefits over traditional instruments. The concentric design is capable of handling high relative apertures, owing to spherical aberration and comma being near zero at all surfaces. The design also provides correction for transverse chromatic aberration and distortion, in addition to correcting for the distortion called "smile", the curvature of the slit image formed at each wavelength. These properties render this design capable of superior spectral and spatial performance with size and weight budgets significantly lower than standard configurations. This form of spectrometer design offers the potential for exceptionally compact instrument for differential optical absorption spectroscopy (DOAS) applications from LEO, GEO, HAP or ground-based platforms. The breadboard demonstrator has been shown to offer high throughput and a stable Gaussian line shape with a spectral range from 300 to 450 nm at 0.5 nm resolution, suitable for a number of typical DOAS applications.

ABSTRACT The high-fidelity modelling of optical turbulence is critical to the design and operation of a new class of emerging highly sophisticated astronomical telescopes and adaptive optics instrumentation. In this study, we perform retrospective simulations of optical turbulence over the Hawaiian islands using a mesoscale model. The simulated results are validated against thermosonde data. We focus on turbulence in the free atmosphere, above the atmospheric boundary layer. The free atmosphere is particularly important for adaptive optics performance and for sky coverage calculations and hence has significant impact on performance optimization and scheduling of observations. We demonstrate that a vertical grid spacing of 100 m or finer is needed to faithfully capture the intrinsic variabilities of observed clear air turbulence. This is a particularly timely study because the next generation of extremely large telescopes are currently under construction and their associated suite of instruments are in the design phase. Knowledge of the expected accuracy of optical turbulence simulations and real-time forecasts will enable the design teams to (i) test and develop instrument designs and (ii) formulate operational procedure.

Abstract. A breadboard demonstrator of a novel UV/VIS grating spectrometer for atmospheric research has been developed based upon a concentric arrangement of a spherical meniscus lens, concave spherical mirror and curved diffraction grating suitable for a range of remote sensing applications from the ground or space. The spectrometer is compact and provides high optical efficiency and performance benefits over traditional instruments. The concentric design is capable of handling high relative apertures, owing to spherical aberration and coma being near zero at all surfaces. The design also provides correction for transverse chromatic aberration and distortion, in addition to correcting for the distortion called "smile", the curvature of the slit image formed at each wavelength. These properties render this design capable of superior spectral and spatial performance with size and weight budgets significantly lower than standard configurations. This form of spectrometer design offers the potential for an exceptionally compact instrument for differential optical absorption spectroscopy (DOAS) applications particularly from space (LEO, GEO orbits) and from HAPs or ground-based platforms. The breadboard demonstrator has been shown to offer high throughput and a stable Gaussian line shape with a spectral range from 300 to 450 nm at better than 0.5 nm resolution, suitable for a number of typical DOAS applications.

A new ultrahigh-energy-resolution and wide-energy-range soft X-ray beamline has been designed and is under construction at the Shanghai Synchrotron Radiation Facility. The beamline has two branches: one dedicated to angle-resolved photoemission spectroscopy (ARPES) and the other to photoelectron emission microscopy (PEEM). The two branches share the same plane-grating monochromator, which is equipped with four variable-line-spacing gratings and covers the 20–2000 eV energy range. Two elliptically polarized undulators are employed to provide photons with variable polarization, linear in every inclination and circular. The expected energy resolution is approximately 10 meV at 1000 eV with a flux of more than 3 × 1010 photons s−1at the ARPES sample positions. The refocusing of both branches is based on Kirkpatrick–Baez pairs. The expected spot sizes when using a 10 µm exit slit are 15 µm × 5 µm (horizontal × vertical FWHM) at the ARPES station and 10 µm × 5 µm (horizontal × vertical FWHM) at the PEEM station. The use of plane optical elements upstream of the exit slit, a variable-line-spacing grating and a pre-mirror in the monochromator that allows the influence of the thermal deformation to be eliminated are essential for achieving the ultrahigh-energy resolution.

Recently there has been a renaissance in scanning cathodoluminescence (CL) microscopy and microanalysis primarily brought about by the analytical demands of the semiconductor industry in addition to significant advances in photonics technology (high efficiency PMTs, CCDs and CL collectors). The strength of the CL analysis technique lies in its ability to provide high spatial (lateral and depth) resolution concentration and distribution information about: (i) the chemical state (identity, oxidation state and co-ordination) of trace level impurities and (ii) point / extended structural defects (vacancies and dislocations) in both semiconductors and insulators.For many materials, interpretation of CL spectra and images measured at low temperature (5 K) is quite straightforward. However CL generation via recombination of electron / hole pairs is a competitive process. Consequently in some specimens the measured CL intensity is not directly proportional to the concentration of the particular luminescent center but relates to the concentration of other radiative or non-radiative centers. In these cases it is difficult to decide whether contrast in the CL image is due to variation in the concentration of the radiative center or the competitive center.

The forte of the Scanning transmission Electron Microscope (STEM) is high resolution imaging with high contrast on thin specimens, as demonstrated by visualization of single heavy atoms. of equal importance for biology is the efficient utilization of all available signals, permitting low dose imaging of unstained single molecules such as DNA.Our work at Brookhaven has concentrated on: 1) design and construction of instruments optimized for a narrow range of biological applications and 2) use of such instruments in a very active user/collaborator program. Therefore our program is highly interactive with a strong emphasis on producing results which are interpretable with a high level of confidence.The major challenge we face at the moment is specimen preparation. The resolution of the STEM is better than 2.5 A, but measurements of resolution vs. dose level off at a resolution of 20 A at a dose of 10 el/A2 on a well-behaved biological specimen such as TMV (tobacco mosaic virus). To track down this problem we are examining all aspects of specimen preparation: purification of biological material, deposition on the thin film substrate, washing, fast freezing and freeze drying. As we attempt to improve our equipment/technique, we use image analysis of TMV internal controls included in all STEM samples as a monitor sensitive enough to detect even a few percent improvement. For delicate specimens, carbon films can be very harsh-leading to disruption of the sample. Therefore we are developing conducting polymer films as alternative substrates, as described elsewhere in these Proceedings. For specimen preparation studies, we have identified (from our user/collaborator program ) a variety of “canary” specimens, each uniquely sensitive to one particular aspect of sample preparation, so we can attempt to separate the variables involved.

The early days of the electron microprobe were characterized by the variety of designs emerging from different laboratories in Europe, the United States and the USSR. Notable amongst these was that of Castaing in 1954, which employed a magnetic lens in combination with an optical microscope for viewing the sample and positioning the electron probe on the desired point for analysis. The X-ray emission was analysed by two high resolution spectrometers having their axes in the same plane as the electron-optical axis, and with their foci accurately set to coincide with the point of impact of the electron probe. This was a design well suited to point analysis by high resolution X-ray spectroscopy and formed the basis of the first Cameca instrument (Fig 1a).By contrast, work by Duncumb in the Cavendish Laboratory in Cambridge started with the object of scanning the electron probe over the sample, in order to image the surface in terms of its characteristic X-ray emission. This required a strong lens to give a high current into a finely focused electron probe (Fig. 1b). The first element maps were demonstrated in 1956, and led to the design of Cambridge Instruments’ Microscan, intended as a metallurgical instrument, in conjunction with D.A. Melford of Tube Investments Research Laboratories.Meanwhile, Long, also in Cambridge, was pioneering applications to mineralogy, and built an instrument for studying conventional slide-mounted rock samples, which could be viewed optically while analysis was in progress (Fig. 1c). This made use of a weaker probe-forming lens, with space for an inclined sample to be viewed in transmitted light. The slim design of the lens allowed it to be partially enclosed in the spectrometer, which received X-rays leaving the sample at a high angle to the surface - a benefit carried through into the Cambridge Geoscan.

Abstract and IntroductionGeophysical field measurements are now more frequently employed to gain information about the ground conditions, so that construction projects can be economically and safely designed. This is especially the case for offshore structures and nuclear power plants or where the ground conditions are poor.Large scale structures require aseismic design and this area of application has been greatly improved, as we can accurately analyse the dynamic properties of the ground. Instruments are also available to monitor the ground behaviour during and after construction so that the new stress conditions can be evaluated.The fields which have been improved recently are: the seismic reflection technique for shallow exploration, the measurement of shear wave velocity to determine dynamic modulus, borehole measurement of all types and most recently radar to give a continuous high resolution section of the near surface. All these techniques have been improved by new technology enhancing the display and plotting capability and S/N ratio, as well as continued development of the theoretical problem.

Abstract. A new approach to autonomously determine concentrations of dissolved inorganic carbon (DIC) and its carbon stable isotope ratio (δ13C–DIC) at high temporal resolution is presented. The simple method requires no customised design. Instead it uses two commercially available instruments currently used in aquatic carbon research. An inorganic carbon analyser utilising non-dispersive infrared detection (NDIR) is coupled to a Cavity Ring-down Spectrometer (CRDS) to determine DIC and δ13C–DIC based on the liberated CO2 from acidified aliquots of water. Using a small sample volume of 2 mL, the precision and accuracy of the new method was comparable to standard isotope ratio mass spectrometry (IRMS) methods. The system achieved a sampling resolution of 16 min, with a DIC precision of ±1.5 to 2 µmol kg−1 and δ13C–DIC precision of ±0.14 ‰ for concentrations spanning 1000 to 3600 µmol kg−1. Accuracy of 0.1 ± 0.06 ‰ for δ13C–DIC based on DIC concentrations ranging from 2000 to 2230 µmol kg−1 was achieved during a laboratory-based algal bloom experiment. The high precision data that can be autonomously obtained by the system should enable complex carbonate system questions to be explored in aquatic sciences using high-temporal-resolution observations.

Small-K Advanced DIffractometer (SKADI is a Small-Angle Neutron Scattering (SANS) instrument to be constructed at the European Spallation Source (ESS). SANS instruments allow investigations of the structure of materials in the size regime between Angstroms up to micrometers. As very versatile instruments, they usually cater to the scientific needs of communities, such as chemists, biologists, and physicists, ranging from material and food sciences to archeology. They can offer analysis of the micro- and mesoscopic structure of the samples, as well as an analysis of the spin states in the samples, for example, for magnetic samples. SKADI, as a broad range instrument, thus offers features, such as an extremely flexible space for the sample environment, to accommodate a wide range of experiments, high-flux, and optimized detector-collimation system to allow for an excellent resolution of the sample structure, short measurement times to be able to record the internal kinetics during a transition in the sample, as well as polarized neutron scattering. In this manuscript, we describe the final design for the construction of SKADI. All of the features and capabilities presented here are projected to be included into the final instrument when going into operation phase.

The Anti-Proton ANnihilation at DArmstadt (PANDA) experiment proposed at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt (Germany) will perform a high-precision spectroscopy of charmonium and exotic hadrons, such as hybrids, glueballs and hypernuclei. A highly intense beam of anti-protons provided by High Energy Storage Ring (HESR) with an unprecedented resolution will scan a mass range of 2 to 5.5 GeV/c2. In preparation for experiments with PANDA, careful and large-scale simulation studies need to be performed in the coming years to determine analysis strategies, to provide feedback for the design, construction and performance optimisation of individual detector components and to design methods for the calibration and interpretation of the experimental results. Results of a simulation for the ElectroMagnetic Calorimeter (EMC), built from lead tungstate (PWO) crystals and placed inside the Target Spectrometer (TS), are presented. The simulations were carried out using the PandaRoot framework, which is based on ROOT and being developed by the PANDA collaboration.

New beamline, BL-15A, was completed at the BL-15 section of the PF-ring in 2014. This new beamline has a short gap undulator which produces high brilliance X-rays ranging from 2.1 keV to 15 keV. The beamline will be dedicated to both activities, XAFS/XRF/XRD studies using semi-micro focus beams (A1 station) and SAXS experiments using collimated softer and hard X-rays (A2 station). In the XAFS/XRF studies, the semi-micro beam available in a wide range of photon energies allows analyzing the local structures of the elements and valence on inhomogeneous samples in the fields of environmental science and new energy source science. The softer X-rays up to 2.1 keV will provide access to absorption edges of phosphor and sulfur, which are very important targets for those fields. The SAXS scientific programs include structural studies of functional membranes, time-resolved X-ray scattering and large hierarchical structure analysis. All of these three programs require a high-brilliance light source. In particular, grazing incidence SAXS (GI-SAXS) using vertically small-size softer beam ranging between 2.1-3.0 keV will help to control the depth of the membrane structure analysis and reduce the roughness defects of an imperfect membrane. The combination of XAFS/XRF and SAXS experiments gives wide structural information from fine atomic structure to low and medium resolution. It can be beneficial to build these instruments as two stations on the same beamline. BL-15A is oriented toward joint advanced studies by the two techniques. Old BL-15 beamlines were scrapped and new construction work started in 2013. The construction was completed in the summer shutdown of 2013 and the first beams was delivered on Oct 17, 2013. We are pursuing the beamline commissioning and the A1 and A2 stations will be opened to users in May, 2014. Here, the beamline design and performance, and the preliminary results will be reported.

Sodium (23Na) is the most abundant cation present in the human body and is involved in a large number of vital body functions. In the last few years, the interest in Sodium Magnetic Resonance Imaging (23Na MRI) has considerably increased for its relevance in physiological and physiopathological aspects. Indeed, sodium MRI offers the possibility to extend the anatomical imaging information by providing additional and complementary information on physiology and cellular metabolism with the heteronuclear Magnetic Resonance Spectroscopy (MRS). Constraints are the rapidly decaying of sodium signal, the sensitivity lack due to the low sodium concentration versus 1H-MRI induce scan times not clinically acceptable and it also constitutes a challenge for sodium MRI. With the available magnetic fields for clinical MRI scanners (1.5 T, 3 T, 7 T), and the hardware capabilities such as strong gradient strengths with high slew rates and new dedicated radiofrequency (RF) sodium coils, it is possible to reach reasonable measurement times (~10–15 min) with a resolution of a few millimeters, where it has already been applied in vivo in many human organs such as the brain, cartilage, kidneys, heart, as well as in muscle and the breast. In this work, we review the different geometries and setup of sodium coils described in the available literature for different in vivo applications in human organs with clinical MR scanners, by providing details of the design, modeling and construction of the coils.

IRAS, COBE, and ISO have demonstrated the unique importance of a cryogenic infrared telescope in space for studying diffuse infrared backgrounds and for teasing out the individual point sources which contribute to them. This importance results from the extremely high infrared sensitivity of such telescopes, particularly to diffuse radiation. The next cryogenic infrared telescope will be NASA's Space Infrared Telescope Facility (SIRTF), which is currently in the final stages of construction leading to launch in 2002. SIRTF will be the first infrared space observatory to make extensive use - both for imaging and spectroscopy - of large format infrared detector arrays. The sensitivity and spatial and spectral coverage of SIRTF's array-based instruments endow SIRTF with great power for the study of the cosmic infrared background (CIRB) and related scientific issues. This paper reviews the SIRTF mission design and measurement functionality and describes SIRTF's potential studies of the CIRB, drawing examples from the programs planned by the SIRTF Guaranteed Time Observers (GTO's). We also summarize the opportunities for community participation in SIRTF.

In the search for the integration of carbon nanostructures in composite and functional materials, covalent organic reactions are successfully performed. This approach resulted in the construction of tailored chemical interfaces facilitating incorporation of nanocarbons. By a combination of different characterization techniques, such as high-resolution X-ray photo-spectroscopy, thermogravimetric analysis, Raman spectroscopy, UV-vis-nIR, and fluorescence spectroscopies, it is possible to identify and quantify the functional moieties covalently attached to the carbon frame. However, the determination of the structural conformation of functionalized nanostructures remains a difficult task. In this work, we present a straightforward methodology to visualize by transmission electron microscopy the functional moieties covalently attached to the carbon network in carbon nanotubes and graphene. The identification of the functionalities occurs in colloidal dispersions by using gold nanoparticles (AuNPs) as discriminating markers by molecular recognition or by the direct growth of AuNPs on the oxygenated moieties. This methodology, in combination with other characterization analysis, is expected to improve the design of hierarchical interfaces by the spatial localization of the functionalities responsible for colloidal stabilization in solvents with different polarities, different from their homogeneous incorporation into different matrices.

This article summarizes the contributions in this special issue on Diffraction-Limited Storage Rings. It analyses the progress in accelerator technology enabling a significant increase in brightness and coherent fraction of the X-ray light provided by storage rings. With MAX IV and Sirius there are two facilities under construction that already exploit these advantages. Several other projects are in the design stage and these will probably enhance the performance further. To translate the progress in light source quality into new science requires similar progress in aspects such as optics, beamline technology, detectors and data analysis. The quality of new science will be limited by the weakest component in this value chain. Breakthroughs can be expected in high-resolution imaging, microscopy and spectroscopy. These techniques are relevant for many fields of science; for example, for the fundamental understanding of the properties of correlated electron materials, the development and characterization of materials for data and energy storage, environmental applications and bio-medicine.

Abstract. In complex and urban environments, atmospheric trace gas composition is highly variable in time and space. Point measurement techniques for trace gases with in situ instruments are well established and accurate, but do not provide spatial averaging to compare against developing high-resolution atmospheric models of composition and meteorology with resolutions of the order of a kilometre. Open-path measurement techniques provide path average concentrations and spatial averaging which, if sufficiently accurate, may be better suited to assessment and interpretation with such models. Open-path Fourier transform spectroscopy (FTS) in the mid-infrared region, and differential optical absorption spectroscopy (DOAS) in the UV and visible, have been used for many years for open-path spectroscopic measurements of selected species in both clean air and in polluted environments. Near infrared instrumentation allows measurements over longer paths than mid-infrared FTS for species such as greenhouse gases which are not easily accessible to DOAS.In this pilot study we present the first open-path near-infrared (4000–10 000 cm−1, 1.0–2.5 µm) FTS measurements of CO2, CH4, O2, H2O and HDO over a 1.5 km path in urban Heidelberg, Germany. We describe the construction of the open-path FTS system, the analysis of the collected spectra, several measures of precision and accuracy of the measurements, and the results a four-month trial measurement period in July–November 2014. The open-path measurements are compared to calibrated in situ measurements made at one end of the open path. We observe significant differences of the order of a few ppm for CO2 and a few tens of ppb for CH4 between the open-path and point measurements which are 2 to 4 times the measurement repeatability, but we cannot unequivocally assign the differences to specific local sources or sinks. We conclude that open-path FTS may provide a valuable new tool for investigations of atmospheric trace gas composition in complex, small-scale environments such as cities.

Abstract Introduction: Magnetic Resonance Spectroscopy (MRS) is a very powerful tool to explore the tissue components, by allowing a selective identification of molecules and molecular distribution mapping. Due to intrinsic Signal-to-Noise Ratio limitations (SNR), MRS in small phantoms and animals with a clinical scanner requires the design and development of dedicated radiofrequency (RF) coils, a task of fundamental importance. In this article, the authors describe the simulation, design, and application of a 1H transmit/receive circular coil suitable for MRS studies in small phantoms and small animal models with a clinical 3T scanner. In particular, the circular coil could be an improvement in animal experiments for tumor studies in which the lesions are localized in specific areas. Material and methods: The magnetic field pattern was calculated using the Biot–Savart law and the inductance was evaluated with analytical calculations. Finally, the coil sensitivity was measured with the perturbing sphere method. Successively, a prototype of the coil was built and tested on the workbench and by the acquisition of MRS data. Results: In this work, we demonstrate the design trade-offs for successfully developing a dedicated coil for MRS experiments in small phantoms and animals with a clinical scanner. The coil designed in the study offers the potential for obtaining MRS data with a high SNR and good spectral resolution. Conclusions: The paper provides details of the design, modelling, and construction of a dedicated circular coil, which represents a low cost and easy to build answer for MRS experiments in small samples with a clinical scanner.

AbstractThe ‘holy grail’ of exoplanet research today is the detection of an earth-like planet: a rocky planet in the habitable zone around a main-sequence star. Extremely precise Doppler spectroscopy is an indispensable tool to find and characterize earth-like planets; however, to find these planets around solar-type stars, we need nearly one order of magnitude better radial velocity (RV) precision than the best current spectrographs provide. Recent developments in astrophotonics (Bland-Hawthorn & Horton 2006, Bland-Hawthorn et al. 2010) and adaptive optics (AO) enable single mode fiber (SMF) fed, high resolution spectrographs, which can realize the next step in precision. SMF feeds have intrinsic advantages over multimode fiber or slit coupled spectrographs: The intensity distribution at the fiber exit is extremely stable, and as a result the line spread function of a well-designed spectrograph is fully decoupled from input coupling conditions, like guiding or seeing variations (Ihle et al. 2010). Modal noise, a limiting factor in current multimode fiber fed instruments (Baudrand & Walker 2001), can be eliminated by proper design, and the diffraction limited input to the spectrograph allows for very compact instrument designs, which provide excellent optomechanical stability. A SMF is the ideal interface for new, very precise wavelength calibrators, like laser frequency combs (Steinmetz et al. 2008, Osterman et al. 2012), or SMF based Fabry-Perot Etalons (Halverson et al. 2013). At near infrared wavelengths, these technologies are ready to be implemented in on-sky instruments, or already in use. We discuss a novel concept for such a spectrograph.

In recent years, the availability of intense continuous radiation sources, such as electron synchrotrons and laser-induced hot plasmas, has given rise to a renewed interest in soft x-ray and x-uv reflectivity measurements. Such studies were, for a long time, hindered because of mainly two reasons. First, it was really difficult to generate soft x-rays in the laboratories and second, there was no possibility for practical implementation and design of optical systems, such as focusing elements, mirrors, etc. associated with that particular wavelength region. Soft x-rays, with wavelength range usually from 10 to about 200 angstroms, can produce images of higher resolution than visible light due to their shorter wavelength. For years, physicists have wanted to construct an x-ray microscope that would exploit the ability of soft x-rays to detect small structures. The need for such an instrument is clear. The resolution of light microscopes is limited by the comparatively long wavelength of visible light. Although transmission electron microscopes have much higher resolution, they are weak in penetrating power and are, therefore, limited to very thin specimens. Therefore, transmission electron microscopy involves extreme care in sample preparation. Such preparations which might alter the very structure of a biological sample, would not be required in x-ray microscopy. The difficulties in constructing an x-ray microscope, however, have proved to be irresistible, because of the fact that soft x-rays cannot be brought together to form an image. In other words, soft x-rays cannot be made reflected from any known single surface at normal or near-normal incidence. The only possibility that existed until now employs grazing incidence, the only form of focusing x-ray optics. But their quality (resolution) has been limited because they must be machined in the form of a paraboloid or hyperboloid. Lenses of the kind used in ordinary optical microscopes cannot be made for use at wavelengths less than about 1000 angstroms. There are two reasons for this. First, there is only a tiny difference in the refractive indices among the different materials at soft x-ray wavelengths. Second, soft x-rays are strongly absorbed by all materials and cannot penetrate any conceivable lens, used in ordinary optical microscopes or telescopes. A major advance in x-ray optics holds a great promise both in the fields of high resolution scanning x-ray microscopy, lithography and substantial improvements in the quality of x-ray telescopes. Recent improvements in the techniques for quality control of evaporated and sputtered films have led to the interest in the controlled fabrication of multilayered structures known as 'Layered Synthetic Microstructures', to be used as mirrors for the extreme ultraviolet and soft x-ray regions. These can be produced with virtually any layer spacing greater than approximately 10 angstroms and they have a considerably high diffraction efficiency at normal or near-normal incidence. This remarkable enhancement in normal-incidence reflectivities at x-uv domain of the electromagnetic spectrum leads to another innovative application of these microstructures, i.e. the production of x-ray lasers with high gain-length products, where the enhanced normal-incidence reflectivity of the multilayers has been applied for multiple pass gain of the laser media by increasing the effective path lengths of the plasma columns. The present article covers the theoretical considerations, development and different techniques of controlled fabrication of layered synthetic microstructures along with their potential applications in the fields of x-ray spectroscopy, microscopy, x-ray laser production and lithography.

METIS, the Mid-infrared ELT Imager and Spectrograph, is currently in its phase A study as one of the candidate first-light instruments for the European Extremely Large Telescope. METIS will feature several observational modes, ranging from diffraction limited imaging in L, M and N-bands to high-resolution Integral Field spectroscopy for the L and M-bands. METIS in its current design gives sensitivities similar to Spitzer in imaging and low-resolution spectroscopy and with its high-resolution spectrograph will provide unprecedented line sensitivity. The design of METIS is optimized for both galactic science cases (e.g. conditions in the early solar system, formation and evolution of proto-planetary disks and properties of exoplanets) and extragalactic science cases (e.g. the growth of Supermassive Black Holes). METIS will require a high-order adaptive optics (AO) system to meet its scientific goals, both to provide correction for atmospheric turbulence as well as reduce the impact of wind shake, leading to a residual image motion of 3 - 5 mas rms. METIS is expected to feature both an internal Single Conjugate AO system as well as an external Laser Tomography AO system. The challenges for the METIS AO system are mainly in the broad correction range, an excellent image stability required for coronagraphy and in providing a high sky coverage to be available for as many science targets as possible. An additional challenge for METIS is the need to compensate for composition turbulence, mainly in the form of fast fluctuations in water vapor concentration. Water vapor fluctuations impact the performance of METIS in several ways: Atmospheric dispersion causes a broadening of the point-spread function, both in the science channel and the wavefront channel, but can be corrected using a Atmospheric Dispersion Corrector. Variations in the water vapor composition cannot be corrected this way and are currently estimated to give a residual image motion of ≤10 mas rms. This effect can, especially for coronagraphy, not be neglected. Chromatic optical path difference errors, caused by changes in the index of refraction along the path through the atmosphere were found to be negligible in the case of METIS due to attenuation by the outer scale (at typical values of 25 m). Chromatic anisoplanatism is the effect that the light at different wavelengths travels through a slightly different light path through the atmosphere and can be–at least partly–corrected. The last effect is composition turbulence, mainly caused by fast (> 1 Hz) fluctuations in the water vapor content. Based on data for ALMA and radiometer probes, this leads to a maximum loss in Strehl ratio between 5 and 10%. This mainly has an impact on coronagraphy and the METIS AO team is actively investigating ways to compensate also water vapor turbulence. The main challenge is currently obtaining reliable data on the distribution and magnitude of precipitable water vapor fluctuations.

Abstract We report an alternative technique to perform a direct and local measurement of electrical resistivities in a layered retinal tissue. Information on resistivity changes along the depth in a retina is important for modelling retinal stimulation by retinal prostheses. Existing techniques for resistivity-depth profiling have the drawbacks of a complicated experimental setup, a less localised resistivity probing and/or lower stability for measurements. We employed a flexible microprobe to measure local resistivity with bipolar impedance spectroscopy at various depths in isolated rat and chick embryo retinas for the first time. Small electrode spacing permitted high resolution measurements and the probe flexibility contributed to stable resistivity profiling. The resistivity was directly calculated based on the resistive part of the impedance measured with the Peak Resistance Frequency (PRF) methodology. The resistivity-depth profiles for both rat and chick embryo models are in accordance with previous mammalian and avian studies in literature. We demonstrate that the measured resistivity at each depth has its own PRF signature. Resistivity profiles obtained with our setup provide the basis for the construction of an electric model of the retina. This model can be used to predict variations in parameters related to retinal stimulation and especially in the design and optimisation of efficient retinal implants.

Background: The determination of drugs in pharmaceutical formulations and human biologic fluids is important for pharmaceutical and medical sciences. Successful analysis requires low sensitivity, high selectivity and minimum interference effects. Current analytical methods can detect drugs at very low levels but these methods require long sample preparation steps, extraction prior to analysis, highly trained technical staff and high-cost instruments. Biosensors offer several advantages such as short analysis time, high sensitivity, real-time analysis, low-cost instruments, and short pretreatment steps over traditional techniques. Biosensors allow quantification not only of the active component in pharmaceutical formulations, but also the degradation products and metabolites in biological fluids. The present review gives comprehensive information on the application of biosensors for drug discovery and analysis. Moreover, this review focuses on the fabrication of these biosensors. Methods: Biosensors can be classified as the utilized bioreceptor and the signal transduction mechanism. The classification based on signal transductions includes electrochemical optical, thermal or acoustic. Electrochemical and optic transducers are mostly utilized transducers used for drug analysis. There are many biological recognition elements, such as enzymes, antibodies, cells that have been used in fabricating of biosensors. Aptamers and antibodies are the most widely used recognition elements for the screening of the drugs. Electrochemical sensors and biosensors have several advantages such as low detection limits, a wide linear response range, good stability and reproducibility. Optical biosensors have several advantages such as direct, real-time and label-free detection of many biological and chemical substances, high specificity, sensitivity, small size and low cost. Modified electrodes enhance sensitivity of the electrodes to develop a new biosensor with desired features. Chemically modified electrodes have gained attention in drug analysis owing to low background current, wide potential window range, simple surface renewal, low detection limit and low cost. Modified electrodes produced by modifying of a solid surface electrode via different materials (carbonaceous materials, metal nanoparticles, polymer, biomolecules) immobilization. Recent advances in nanotechnology offer opportunities to design and construct biosensors. Unique features of nanomaterials provide many advantages in the fabrication of biosensors. Nanomaterials have controllable chemical structures, large surface to volume ratios, functional groups on their surface. To develop proteininorganic hybrid nanomaterials, four preparation methods have been used. These methods are immobilization, conjugation, crosslinking and self-assembly. In the present manuscript, applications of different biosensors, fabricated by using several materials, for drug analysis are reviewed. The biosensing strategies are investigated and discussed in detail. Results: Several analytical techniques such as chromatography, spectroscopy, radiometry, immunoassays and electrochemistry have been used for drug analysis and quantification. Methods based on chromatography require timeconsuming procedure, long sample-preparation steps, expensive instruments and trained staff. Compared to chromatographic methods, immunoassays have simple protocols and lower cost. Electrochemical measurements have many advantages over traditional chemical analyses and give information about drug quantity, metabolic fate of drugs, and pharmacological activity. Moreover, the electroanalytical methods are useful to determine drugs sensitively and selectivity. Additionally, these methods decrease analysis cost and require low-cost instruments and simple sample pretreatment steps. Conclusion: In recent years, drug analyses are performed using traditional techniques. These techniques have a good detection limit, but they have some limitations such as long analysis time, expensive device and experienced personnel requirement. Increased demand for practical and low-cost analytical techniques biosensor has gained interest for drug determinations in medical sciences. Biosensors are unique and successful devices when compared to traditional techniques. For drug determination, different electrode modification materials and different biorecognition elements are used for biosensor construction. Several biosensor construction strategies have been developed to enhance the biosensor performance. With the considerable progress in electrode surface modification, promotes the selectivity of the biosensor, decreases the production cost and provides miniaturization. In the next years, advances in technology will provide low cost, sensitive, selective biosensors for drug analysis in drug formulations and biological samples.

The Jules Horowitz Reactor (JHR) is a European material testing reactor (MTR) under construction at the CEA Cadarache centre. It will be dedicated to material and fuel irradiation tests, as well as to the production of medical isotopes. Gamma and X-Ray benches will be implemented in the reactor pool (RER), the irradiated component storage pool (EPI) and in a shielded hot cell for measuring either the whole underwater test device still containing the experimental sample or just the experimental sample before its extraction in the hot cell. The CEA/Cadarache Nuclear Measurement Laboratory (LMN) has been working in collaboration with VTT (Technical Research Centre in Finland Ltd.) since 2008 under a Finnish in-kind contribution agreement. This agreement focuses on the development of NDE systems implementing gamma-ray spectroscopy and high-energy X-ray imaging of the sample and irradiation device with the highest definition possible (resolution of 100 μm). The CEA-VTT technical specifications led to a European call for tenders launched by VTT. The contract was awarded to the Spanish company IDOM for the design, manufacturing, assembly and commissioning of: - Underwater gamma and X-ray (UGXR) mechanical benches and their associated gamma and X-ray collimation systems for the RER and EPI pools - Hot cell gamma and X-ray (HGXR) bench in the JHR NDE hot cell. The Final Design Reviews (FDR) of the UGXR and HGXR systems were completed in 2016. The design phase has been an iterative process in order to manage interfacing specifications and constraints: - Challenging experimental requirements, mainly to cover the wide diversity of sample shapes, sample activity levels and measurement processes, but also to achieve a level of mechanical accuracy to reach the ambitious geometrical resolution target in X-ray imaging, - Environmental constraints (immersion, radiation, compactness, limited accessibility for maintenance), - Nuclear safety constraints (seism, radiation protection). The whole design process has produced a number of elaborate and innovative mechatronic systems, which is rather unusual in nuclear applications since the resulting solutions have benefited from IDOM’s technological expertise in designing and commissioning large telescopes for the astronomy sector. Once the manufacturing phase and assembly finalised, the site acceptance tests for the UGXR and HGXR mechanical systems will be performed in 2019-2020 in the TOTEM facility at the CEA Cadarache center. The underwater benches will be tested in the CESARINE pool to check their requirements.

Abstract Portable instruments such as ocean bottom seismographs and the PASSCAL recorders often use rugged, portable geophones. The desire to use such sensors for relatively low-frequency work has raised questions about the limits of their sensitivity. The lower and upper frequency limits of performance of seismic sensors are determined by the sensor's mass, period, and Q, and by the amplifiers used with those sensors. We have tested Mark Products 1 Hz, 2 Hz, and 4.5 Hz velocity transducers against Streckeisen seismometers in order to examine the limits of their performance in measuring ground noise, particularly at low frequencies. Among the velocity transducers, only the 1 Hz Mark Products L-4 sensor provided good resolution of the 6-sec microseism peak. For this sensor, the lower limits of sensitivity was at approximately 0.06 Hz, although this depends on the amplifier used and the noise level at a given site. The amplifiers examined included conventional, low power, and commutating auto-zero operational amplifiers. It was found that the noise levels of the amplifiers intersected the ground noise level at frequencies ranging between 0.06 and 0.2 sec, depending on the amplifier and the exact circuit design. Measurements indicated that by modeling the amplifier noise for a given circuit correctly, the performance of an amplifier can be predicted with a high degree of accuracy, obviating the need for actual circuit construction to determine performance in the field. Given the very steep slope of the ground noise spectrum between 0.05 and 0.1 Hz and the rapid fall off in a seismometer's output below its resonant frequency, it would require a lowering of amplifier noise by more than an order of magnitude to be able to resolve ground noise at frequencies lower than 0.05 Hz using relatively small geophones such as the L-4. To resolve ground noise at lower frequencies, it is necessary to use a seismometer with a displacement transducer to sense the mass position, such as Guralp or Streckeisen sensors.

AbstractWe present an overview of the National Science Foundation’s Daniel K. Inouye Solar Telescope (DKIST), its instruments, and support facilities. The 4 m aperture DKIST provides the highest-resolution observations of the Sun ever achieved. The large aperture of DKIST combined with state-of-the-art instrumentation provide the sensitivity to measure the vector magnetic field in the chromosphere and in the faint corona, i.e. for the first time with DKIST we will be able to measure and study the most important free-energy source in the outer solar atmosphere – the coronal magnetic field. Over its operational lifetime DKIST will advance our knowledge of fundamental astronomical processes, including highly dynamic solar eruptions that are at the source of space-weather events that impact our technological society. Design and construction of DKIST took over two decades. DKIST implements a fast (f/2), off-axis Gregorian optical design. The maximum available field-of-view is 5 arcmin. A complex thermal-control system was implemented in order to remove at prime focus the majority of the 13 kW collected by the primary mirror and to keep optical surfaces and structures at ambient temperature, thus avoiding self-induced local seeing. A high-order adaptive-optics system with 1600 actuators corrects atmospheric seeing enabling diffraction limited imaging and spectroscopy. Five instruments, four of which are polarimeters, provide powerful diagnostic capability over a broad wavelength range covering the visible, near-infrared, and mid-infrared spectrum. New polarization-calibration strategies were developed to achieve the stringent polarization accuracy requirement of 5×10−4. Instruments can be combined and operated simultaneously in order to obtain a maximum of observational information. Observing time on DKIST is allocated through an open, merit-based proposal process. DKIST will be operated primarily in “service mode” and is expected to on average produce 3 PB of raw data per year. A newly developed data center located at the NSO Headquarters in Boulder will initially serve fully calibrated data to the international users community. Higher-level data products, such as physical parameters obtained from inversions of spectro-polarimetric data will be added as resources allow.

Everyday science has had to resort to the construction of large facilities and instruments to carry out experiments that allow obtaining information so that it can be analyzed later. In nuclear physics, the creation of new facilities has been growing enormously since to study this area of physics it has been necessary to build accelerators, magnetic spectrometers and detectors in order to obtain experimental information of events on a microscopic scale. This article reviews the design and construction process of the SUPER-FRS (Super-Fragment Separator) magnetic high resolution spectrometer resulting from a great collaboration called FAIR in (Darmstadt) Germany in the GSI facilities with the In order to know the scientific motivation that led to build it, its technical design and work that has been done on it.

Introduction Explorations of the multimedia game format within cultural studies have been broadly approached from two perspectives: one -- the impact of technologies on user interaction particularly with regard to social implications, and the other -- human computer interactions within the framework of cybercultures. Another approach to understanding or speaking about games within cultural studies is to focus on the game experience as cultural practice -- as an activity or an event. In this article I wish to initiate an exploration of the aesthetics of player space as a distinctive element of the gameplay experience. In doing so I propose that an understanding of aesthetic spatial issues as an element of player interactivity and engagement is important for understanding the cultural practice of adventure gameplay. In approaching these questions, I am focussing on the single-player exploration adventure game in particular Myst and The Crystal Key. In describing these games as adventures I am drawing on Chris Crawford's The Art of Computer Game Design, which although a little dated, focusses on game design as a distinct activity. He brings together a theoretical approach with extensive experience as a game designer himself (Excalibur, Legionnaire, Gossip). Whilst at Atari he also worked with Brenda Laurel, a key theorist in the area of computer design and dramatic structure. Adventure games such as Myst and The Crystal Key might form a sub-genre in Chris Crawford's taxonomy of computer game design. Although they use the main conventions of the adventure game -- essentially a puzzle to be solved with characters within a story context -- the main focus and source of pleasure for the player is exploration, particularly the exploration of worlds or cosmologies. The main gameplay of both games is to travel through worlds solving clues, picking up objects, and interacting with other characters. In Myst the player has to solve the riddle of the world they have entered -- as the CD-ROM insert states "Now you're here, wherever here is, with no option but to explore." The goal, as the player must work out, is to release the father Atrus from prison by bringing magic pages of a book to different locations in the worlds. Hints are offered by broken-up, disrupted video clips shown throughout the game. In The Crystal Key, the player as test pilot has to save a civilisation by finding clues, picking up objects, mending ships and defeating an opponent. The questions foregrounded by a focus on the aesthetics of navigation are: What types of representational context are being set up? What choices have designers made about representational context? How are the players positioned within these spaces? What are the implications for the player's sense of orientation and navigation? Architectural Fabrication For the ancient Greeks, painting was divided into two categories: magalography (the painting of great things) and rhyparography (the painting of small things). Magalography covered mythological and historical scenes, which emphasised architectural settings, the human figure and grand landscapes. Rhyparography referred to still lifes and objects. In adventure games, particularly those that attempt to construct a cosmology such as Myst and The Crystal Key, magalography and rhyparography collide in a mix of architectural monumentality and obsessive detailing of objects. For the ancient Greeks, painting was divided into two categories: magalography (the painting of great things) and rhyparography (the painting of small things). Magalography covered mythological and historical scenes, which emphasised architectural settings, the human figure and grand landscapes. Rhyparography referred to still lifes and objects. In adventure games, particularly those that attempt to construct a cosmology such as Myst and The Crystal Key, magalography and rhyparography collide in a mix of architectural monumentality and obsessive detailing of objects. The creation of a digital architecture in adventure games mimics the Pompeii wall paintings with their interplay of extruded and painted features. In visualising the space of a cosmology, the environment starts to be coded like the urban or built environment with underlying geometry and textured surface or dressing. In The Making of Myst (packaged with the CD-ROM) Chuck Carter, the artist on Myst, outlines the process of creating Myst Island through painting the terrain in grey scale then extruding the features and adding textural render -- a methodology that lends itself to a hybrid of architectural and painted geometry. Examples of external architecture and of internal room design can be viewed online. In the spatial organisation of the murals of Pompeii and later Rome, orthogonals converged towards several vertical axes showing multiple points of view simultaneously. During the high Renaissance, notions of perspective developed into a more formal system known as the construzione legittima or legitimate construction. This assumed a singular position of the on-looker standing in the same place as that occupied by the artist when the painting was constructed. In Myst there is an exaggeration of the underlying structuring technique of the construzione legittima with its emphasis on geometry and mathematics. The player looks down at a slight angle onto the screen from a fixed vantage point and is signified as being within the cosmological expanse, either in off-screen space or as the cursor. Within the cosmology, the island as built environment appears as though viewed through an enlarging lens, creating the precision and coldness of a Piero della Francesca painting. Myst mixes flat and three-dimensional forms of imagery on the same screen -- the flat, sketchy portrayal of the trees of Myst Island exists side-by-side with the monumental architectural buildings and landscape design structures created in Macromodel. This image shows the flat, almost expressionistic trees of Myst Island juxtaposed with a fountain rendered in high detail. This recalls the work of Giotto in the Arena chapel. In Joachim's Dream, objects and buildings have depth, but trees, plants and sky -- the space in-between objects -- is flat. Myst Island conjures up the realm of a magic, realist space with obsolete artefacts, classic architectural styles (the Albert Hall as the domed launch pad, the British Museum as the library, the vernacular cottage in the wood), mechanical wonders, miniature ships, fountains, wells, macabre torture instruments, ziggurat-like towers, symbols and odd numerological codes. Adam Mates describes it as "that beautiful piece of brain-deadening sticky-sweet eye-candy" but more than mere eye-candy or graphic verisimilitude, it is the mix of cultural ingredients and signs that makes Myst an intriguing place to play. The buildings in The Crystal Key, an exploratory adventure game in a similar genre to Myst, celebrate the machine aesthetic and modernism with Buckminster Fuller style geodesic structures, the bombe shape, exposed ducting, glass and steel, interiors with movable room partitions and abstract expressionist decorations. An image of one of these modernist structures is available online. The Crystal Key uses QuickTime VR panoramas to construct the exterior and interior spaces. Different from the sharp detail of Myst's structures, the focus changes from sharp in wide shot to soft focus in close up, with hot-spot objects rendered in trompe l'oeil detail. The Tactility of Objects "The aim of trompe l'oeil -- using the term in its widest sense and applying it to both painting and objects -- is primarily to puzzle and to mystify" (Battersby 19). In the 15th century, Brunelleschi invented a screen with central apparatus in order to obtain exact perspective -- the monocular vision of the camera obscura. During the 17th century, there was a renewed interest in optics by the Dutch artists of the Rembrandt school (inspired by instruments developed for Dutch seafaring ventures), in particular Vermeer, Hoogstraten, de Hooch and Dou. Gerard Dou's painting of a woman chopping onions shows this. These artists were experimenting with interior perspective and trompe l'oeil in order to depict the minutia of the middle-class, domestic interior. Within these luminous interiors, with their receding tiles and domestic furniture, is an elevation of the significance of rhyparography. In the Girl Chopping Onions of 1646 by Gerard Dou the small things are emphasised -- the group of onions, candlestick holder, dead fowl, metal pitcher, and bird cage. Trompe l'oeil as an illusionist strategy is taken up in the worlds of Myst, The Crystal Key and others in the adventure game genre. Traditionally, the fascination of trompe l'oeil rests upon the tension between the actual painting and the scam; the physical structures and the faux painted structures call for the viewer to step closer to wave at a fly or test if the glass had actually broken in the frame. Mirian Milman describes trompe l'oeil painting in the following manner: "the repertory of trompe-l'oeil painting is made up of obsessive elements, it represents a reality immobilised by nails, held in the grip of death, corroded by time, glimpsed through half-open doors or curtains, containing messages that are sometimes unreadable, allusions that are often misunderstood, and a disorder of seemingly familiar and yet remote objects" (105). Her description could be a scene from Myst with in its suggestion of theatricality, rich texture and illusionistic play of riddle or puzzle. In the trompe l'oeil painterly device known as cartellino, niches and recesses in the wall are represented with projecting elements and mock bas-relief. This architectural trickery is simulated in the digital imaging of extruded and painting elements to give depth to an interior or an object. Other techniques common to trompe l'oeil -- doors, shadowy depths and staircases, half opened cupboard, and paintings often with drapes and curtains to suggest a layering of planes -- are used throughout Myst as transition points. In the trompe l'oeil paintings, these transition points were often framed with curtains or drapes that appeared to be from the spectator space -- creating a painting of a painting effect. Myst is rich in this suggestion of worlds within worlds through the framing gesture afforded by windows, doors, picture frames, bookcases and fireplaces. Views from a window -- a distant landscape or a domestic view, a common device for trompe l'oeil -- are used in Myst to represent passageways and transitions onto different levels. Vertical space is critical for extending navigation beyond the horizontal through the terraced landscape -- the tower, antechamber, dungeon, cellars and lifts of the fictional world. Screen shots show the use of the curve, light diffusion and terracing to invite the player. In The Crystal Key vertical space is limited to the extent of the QTVR tilt making navigation more of a horizontal experience. Out-Stilling the Still Dutch and Flemish miniatures of the 17th century give the impression of being viewed from above and through a focussing lens. As Mastai notes: "trompe l'oeil, therefore is not merely a certain kind of still life painting, it should in fact 'out-still' the stillest of still lifes" (156). The intricate detailing of objects rendered in higher resolution than the background elements creates a type of hyper-reality that is used in Myst to emphasise the physicality and actuality of objects. This ultimately enlarges the sense of space between objects and codes them as elements of significance within the gameplay. The obsessive, almost fetishistic, detailed displays of material artefacts recall the curiosity cabinets of Fabritius and Hoogstraten. The mechanical world of Myst replicates the Dutch 17th century fascination with the optical devices of the telescope, the convex mirror and the prism, by coding them as key signifiers/icons in the frame. In his peepshow of 1660, Hoogstraten plays with an enigma and optical illusion of a Dutch domestic interior seen as though through the wrong end of a telescope. Using the anamorphic effect, the image only makes sense from one vantage point -- an effect which has a contemporary counterpart in the digital morphing widely used in adventure games. The use of crumbled or folded paper standing out from the plane surface of the canvas was a recurring motif of the Vanitas trompe l'oeil paintings. The highly detailed representation and organisation of objects in the Vanitas pictures contained the narrative or symbology of a religious or moral tale. (As in this example by Hoogstraten.) In the cosmology of Myst and The Crystal Key, paper contains the narrative of the back-story lovingly represented in scrolls, books and curled paper messages. The entry into Myst is through the pages of an open book, and throughout the game, books occupy a privileged position as holders of stories and secrets that are used to unlock the puzzles of the game. Myst can be read as a Dantesque, labyrinthine journey with its rich tapestry of images, its multi-level historical associations and battle of good and evil. Indeed the developers, brothers Robyn and Rand Miller, had a fertile background to draw on, from a childhood spent travelling to Bible churches with their nondenominational preacher father. The Diorama as System Event The diorama (story in the round) or mechanical exhibit invented by Daguerre in the 19th century created a mini-cosmology with player anticipation, action and narrative. It functioned as a mini-theatre (with the spectator forming the fourth wall), offering a peek into mini-episodes from foreign worlds of experience. The Musée Mechanique in San Francisco has dioramas of the Chinese opium den, party on the captain's boat, French execution scenes and ghostly graveyard episodes amongst its many offerings, including a still showing an upper class dancing party called A Message from the Sea. These function in tandem with other forbidden pleasures of the late 19th century -- public displays of the dead, waxwork museums and kinetescope flip cards with their voyeuristic "What the Butler Saw", and "What the Maid Did on Her Day Off" tropes. Myst, along with The 7th Guest, Doom and Tomb Raider show a similar taste for verisimilitude and the macabre. However, the pre-rendered scenes of Myst and The Crystal Key allow for more diorama like elaborate and embellished details compared to the emphasis on speed in the real-time-rendered graphics of the shoot-'em-ups. In the gameplay of adventure games, animated moments function as rewards or responsive system events: allowing the player to navigate through the seemingly solid wall; enabling curtains to be swung back, passageways to appear, doors to open, bookcases to disappear. These short sequences resemble the techniques used in mechanical dioramas where a coin placed in the slot enables a curtain or doorway to open revealing a miniature narrative or tableau -- the closure of the narrative resulting in the doorway shutting or the curtain being pulled over again. These repeating cycles of contemplation-action-closure offer the player one of the rewards of the puzzle solution. The sense of verisimilitude and immersion in these scenes is underscored by the addition of sound effects (doors slamming, lifts creaking, room atmosphere) and music. Geographic Locomotion Static imagery is the standard backdrop of the navigable space of the cosmology game landscape. Myst used a virtual camera around a virtual set to create a sequence of still camera shots for each point of view. The use of the still image lends itself to a sense of the tableauesque -- the moment frozen in time. These tableauesque moments tend towards the clean and anaesthetic, lacking any evidence of the player's visceral presence or of other human habitation. The player's navigation from one tableau screen to the next takes the form of a 'cyber-leap' or visual jump cut. These jumps -- forward, backwards, up, down, west, east -- follow on from the geographic orientation of the early text-based adventure games. In their graphic form, they reveal a new framing angle or point of view on the scene whilst ignoring the rules of classical continuity editing. Games such as The Crystal Key show the player's movement through space (from one QTVR node to another) by employing a disorientating fast zoom, as though from the perspective of a supercharged wheelchair. Rather than reconciling the player to the state of movement, this technique tends to draw attention to the technologies of the programming apparatus. The Crystal Key sets up a meticulous screen language similar to filmic dramatic conventions then breaks its own conventions by allowing the player to jump out of the crashed spaceship through the still intact window. The landscape in adventure games is always partial, cropped and fragmented. The player has to try and map the geographical relationship of the environment in order to understand where they are and how to proceed (or go back). Examples include selecting the number of marker switches on the island to receive Atrus's message and the orientation of Myst's tower in the library map to obtain key clues. A screenshot shows the arrival point in Myst from the dock. In comprehending the landscape, which has no centre, the player has to create a mental map of the environment by sorting significant connecting elements into chunks of spatial elements similar to a Guy Debord Situationist map. Playing the Flaneur The player in Myst can afford to saunter through the landscape, meandering at a more leisurely pace that would be possible in a competitive shoot-'em-up, behaving as a type of flaneur. The image of the flaneur as described by Baudelaire motions towards fin de siècle decadence, the image of the socially marginal, the dispossessed aristocrat wandering the urban landscape ready for adventure and unusual exploits. This develops into the idea of the artist as observer meandering through city spaces and using the power of memory in evoking what is observed for translation into paintings, writing or poetry. In Myst, the player as flaneur, rather than creating paintings or writing, is scanning the landscape for clues, witnessing objects, possible hints and pick-ups. The numbers in the keypad in the antechamber, the notes from Atrus, the handles on the island marker, the tower in the forest and the miniature ship in the fountain all form part of a mnemomic trompe l'oeil. A screenshot shows the path to the library with one of the island markers and the note from Atrus. In the world of Myst, the player has no avatar presence and wanders around a seemingly unpeopled landscape -- strolling as a tourist venturing into the unknown -- creating and storing a mental map of objects and places. In places these become items for collection -- cultural icons with an emphasised materiality. In The Crystal Key iconography they appear at the bottom of the screen pulsing with relevance when active. A screenshot shows a view to a distant forest with the "pick-ups" at the bottom of the screen. This process of accumulation and synthesis suggests a Surrealist version of Joseph Cornell's strolls around Manhattan -- collecting, shifting and organising objects into significance. In his 1982 taxonomy of game design, Chris Crawford argues that without competition these worlds are not really games at all. That was before the existence of the Myst adventure sub-genre where the pleasures of the flaneur are a particular aspect of the gameplay pleasures outside of the rules of win/loose, combat and dominance. By turning the landscape itself into a pathway of significance signs and symbols, Myst, The Crystal Key and other games in the sub-genre offer different types of pleasures from combat or sport -- the pleasures of the stroll -- the player as observer and cultural explorer. References Battersby, M. Trompe L'Oeil: The Eye Deceived. New York: St. Martin's, 1974. Crawford, C. The Art of Computer Game Design. Original publication 1982, book out of print. 15 Oct. 2000 <http://members.nbci.com/kalid/art/art.php>. Darley Andrew. Visual Digital Culture: Surface Play and Spectacle in New Media Genres. London: Routledge, 2000. Lunenfeld, P. Digital Dialectic: New Essays on New Media. Cambridge, Mass.: MIT P 1999. Mates, A. Effective Illusory Worlds: A Comparative Analysis of Interfaces in Contemporary Interactive Fiction. 1998. 15 Oct. 2000 <http://www.wwa.com/~mathes/stuff/writings>. Mastai, M. L. d'Orange. Illusion in Art, Trompe L'Oeil: A History of Pictorial Illusion. New York: Abaris, 1975. Miller, Robyn and Rand. "The Making of Myst." Myst. Cyan and Broderbund, 1993. Milman, M. Trompe-L'Oeil: The Illusion of Reality. New York: Skira Rizzoli, 1982. Murray, J. Hamlet on the Holodeck: The Future of Narrative in Cyberspace. New York: Simon and Schuster, 1997. Wertheim, M. The Pearly Gates of Cyberspace: A History of Cyberspace from Dante to the Internet. Sydney: Doubleday, 1999. Game References 7th Guest. Trilobyte, Inc., distributed by Virgin Games, 1993. Doom. Id Software, 1992. Excalibur. Chris Crawford, 1982. Myst. Cyan and Broderbund, 1993. Tomb Raider. Core Design and Eidos Interactive, 1996. The Crystal Key. Dreamcatcher Interactive, 1999. Citation reference for this article MLA style: Bernadette Flynn. "Towards an Aesthetics of Navigation -- Spatial Organisation in the Cosmology of the Adventure Game." M/C: A Journal of Media and Culture 3.5 (2000). [your date of access] <http://www.api-network.com/mc/0010/navigation.php>. Chicago style: Bernadette Flynn, "Towards an Aesthetics of Navigation -- Spatial Organisation in the Cosmology of the Adventure Game," M/C: A Journal of Media and Culture 3, no. 5 (2000), <http://www.api-network.com/mc/0010/navigation.php> ([your date of access]). APA style: Bernadette Flynn. (2000) Towards an aesthetics of navigation -- spatial organisation in the cosmology of the adventure game. M/C: A Journal of Media and Culture 3(5). <http://www.api-network.com/mc/0010/navigation.php> ([your date of access]).