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Celestial objects are often home to complex, dynamic, intriguing environments. High-resolution x-ray spectra from these sources measured by satellites such as the Chandra, XMM-Newton, the Solar Maximum Mission, and the soon-to-be-launched Astro-E2 provide a means for understanding the physics governing these sources. Especially rich is the x-ray emission from L-shell transitions in highly charged iron ions. This emission is the source of a variety of diagnostics whose utility lies in the accuracy of the atomic data employed to model the x-ray spectra. The atomic data used to describe these diagnostics are generally provided by large theoretical calculations and benchmarked by laboratory data. In this paper we discuss laboratory measurements of Fe L-shell x-ray emission including wavelengths, relative and absolute excitation cross sections, and line ratios that provide diagnostics of temperature and density. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The iron L-shell ions (Fe[sup 17+] to Fe[sup 23+]) play an important role in determining the thermal and ionization structures and line emission from photoionized plasmas. Current uncertainties in the theoretical low temperature dielectronic recombination (DR) rate coefficients for these ions significantly affect our ability to model and interpret the line emission from observations of photoionized plasmas. To help resolve this issue, we have initiated a program of laboratory measurements to produce reliable low temperature DR rates for the L-shell iron. Here we present some of our recent results and discuss some of the astrophysical implications. [ABSTRACT FROM AUTHOR]

We discuss the conceptual design of a system to reduce the 6D emittance of a circulating muon beam. This system utilizes ionization cooling to achieve 6D phase reduction of the beam. Our design is based on a hydrogen gas filled ring which incorporates optics consisting of weak-focusing dipoles and 200 MHz rf cavities which restore the ionization energy loss due to the muons traversing the hydrogen gas. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The mixing of atomic and macroscopic processes taking place in non-terrestrial objects creates complex, dynamic, and intriguing environments. High resolution x-ray spectra from these sources measured by satellites such as Chandra, XMM-Newton, and the Solar Maximum Mission provide a means for understanding the physics governing these sources. Laboratory measurements of the atomic processes have proved crucial to the interpretation of these spectra. For example using the LLNL electron beam ion traps EBIT-I & EBIT-II a detailed study of the x-ray spectrum of Fe XVII has been conducted addressing the large ratio predicted by theory compared to observations of considerably smaller values of the relative intensity of the 2p-3d 1P1 resonant to the 3D1 intercombination line. The difference was often attributed to opacity effects. However, laboratory measurements in the optically thin limit agree with observations demonstrating that the prediction is too large and opacity need not be invoked. The laboratory results thus provide a benchmark in the optically thin limit for accurate estimates of opacity effects . To uncover the source of the discrepancy between theory and observation, we have performed a series of experiments that successively uncovered more details about the Fe XVII lines produced in coronal plasmas. Most recently, we used a 32 channel array microcalorimeter from the Astro-E x-ray satellite program to measure the excitation cross section of various Fe XVII lines in the laboratory. These measurements resolve long-standing issues thought to be associated with non-equilibrium processes. We have also used the Astro-E microcalorimeter, and more recently its upgrade from the Astro-E2 project, and the magnetic trapping mode of EBIT-I to accurately measure x-ray emission from charge exchange recombination and to simulate the x-ray line production process in comets. Using only the laboratory measurements, we fit the moderate resolution x-ray spectrum from the comet C/Linear1999 observed by the ACIS-S CCD instrument on the Chandra X-ray Observatory . The good fit to the data shows that we are able to recreate in the laboratory the charge exchange process taking place in comets. With the launch of the Astro-E2 satellite in 2005, whose second generation XRS microcalorimeter array has an energy resolution of 6–7 eV, a factor of 20–30 better than Chandra’s ACIS-S CCD, high resolution spectra of comets should become available. These measurements coupled with the laboratory measurements at LLNL using the sister Astro-E2 calorimeter array, will make it possible to accurately diagnose the composition of the solar wind at various locations in the solar system. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

Recent simulations have shown that muon cooling rings can effectively reduce both longitudinal and transverse emittance. The muon collaboration is investigating several varieties of muon cooling rings. This study looks at the first of these ring cooling scenarios that was proposed by V. Balbekov. This simulation of this ring shows significant cooling in the hardedge field approximation. We discuss the status of using realistic fields in the tetra simulation. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

We have recently deployed an XRS (the X-ray Spectrometer on the Astro-E mission) engineering model microcalorimeter at the electron beam ion traps (EBIT I/II) at Lawrence Livermore National Laboratory. The EBIT I/II can produce well defined astrophysically interesting plasmas for a wide range of plasma conditions. The XRS engineering model was mated with a 32 element XRS 6x6 microcalorimeter array and integrated into a laboratory cryostat. The system was then transported to the EBIT I/II and operated over the last year. The microcalorimeter array has a composite resolution of 8 eV at 1 keV and 11 eV at 6 keV. During the campaign, we performed a number of high resolution, broad band observations including: K and L shell Fe with single ionization energies from 1 - 8 keV, Maxwellian distributions of Fe with = 0.5 3 keV, non-equilibrium states of Fe with very fine time resolution for η = 10[sup 9] - 10[sup 12] S cm[sup -3]. The total observation time for the campaign was over 10 Ms and the analysis is ongoing. We will present here an overview of the instrument and a few of the preliminary results. The results of these experiments show the power and promise of the XRS microcalorimeter and give a detailed picture of how the instrument would have performed in orbit on Astro-E, and will perform in the future on the Astro-E2 mission. [ABSTRACT FROM AUTHOR]

The potentially large background produced from the decay products of muons could affect the quality of the physics in a high energy muon collider. This paper examines the kinds of background present and their expected rate. The results are based on a simulation of muon colliders with center of mass energies of 100 GeV, 500 GeV and 4 TeV. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The challenges to design, construct and operate a detector system in an interaction region at a high energy μ[sup +]μ[sup -] collider are briefly summarized. A new solution, based on an extensive use of liquefied rare gases, is proposed for the vertex detector and for the inner tracker. The proposed solution takes a full advantage of the small size of the collision region. The region has radial dimensions below the μm range, while its extent in the beam direction is of the order of 1mm depending on the energy of the machine and on the details of the design. In the energy range considered in this workshop, the momenta of charged particles are high enough to be bent only slightly in the solenoidal magnetic field. The tracks are basically straight lines emerging from a known common point. The proposed solution is based on a projective geometry matched to the desired tracks. The aim of the design is to achieve a background blind radiation hard detector. The second novel feature of the design is the calorimetric instrumentation of two large 20° tungsten cones used to shield the detector from the machine induced background. Here again the full advantage of the known directionality of particles initiating the shower process is incorporated into the design. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

An overview is given of measurements of the Fe K-shell spectrum from low-density laboratory sources. The measurements include wavelengths, electron-impact collision cross sections, innershell ionization phenomena, dielectronic recombination resonance strengths, charge exchange recombination, electron beam polarization effects, resonance excitation, and radiative cascade contributions. K-shell spectra have now also been obtained with microcalorimeters, including microcalorimeter arrays that are twins of the ASTRO-E and ASTRO-E2 missions, which illustrate typical resolving powers and spectral capabilities. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Emission lines from L-shell ions of iron dominates the soft X-ray spectral band for hot collisionally-ionized plasmas with temperatures near 106 K. These lines also contribute significantly in the spectra of photoionized plasmas at lower temperatures. To accurately model such spectra, a large set of atomic data is needed, including wavelengths, radiative transition rates, collisional excitation, radiative and dielectronic recombination rates, and collisional ionization. We review the recent theoretical efforts in producing such atomic parameters and assess their accuracy by comparing them with the experimental measurements wherever available. We also compare the close-coupling and distorted-wave theoretical approaches in treating the collisional excitation of Fe L-shell ions. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Recent measurements of the K-shell and L-shell x-ray spectra of highly charged heliumlike and neonlike ions are presented that were performed on the Livermore electron beam ion traps and the Princeton tokamaks. These measurements provide new insights into collisional and indirect line formation processes, identifications of forbidden lines, and a new plasma line diagnostic of magnetic field strength. [ABSTRACT FROM AUTHOR]

The ratios of the Fe XVII 3s → 2p transitions to that of the dominant 3d → 2p transition measured in high-temperature tokamak plasmas are compared to solar and astrophysical observations. Good agreement is found, demonstrating that the collisional line formation processes active in opacity-free, low-density, high-temperature laboratory plasmas are a good description of those found in astrophysical plasmas. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

A theoretical model for charge transfer reaction at molecule metal interface has developed. Many solvents for charge transfer media used to knowing and discussion the effect of polarity media on flow transfer. HATNA and HATNA-CI6 molecules using to contact with Cu metal. The theoretical model discussion the mechanism of charge transfer in two system. HATNA- CI6/Cu interface show large flow charge transfer compare with HATNA /Cu. The flow charge rate increases with increases strength coupling and driving force energy and decreasing with increases transition energy. [ABSTRACT FROM AUTHOR]

Titanium dioxide is widely used as an electron selective layer for silicon based carrier selective solar cells. For efficient carrier collection, the TiO2 film should passivate the Si surface, while maintaining its selective nature – which requires careful optimization of process conditions. Here, we compare the properties of TiO2 films deposited by plasma and thermal Atomic Layer Deposition (ALD). We observe that the films deposited without plasma are indeed more oxygen deficient, but interestingly provide better passivation of the silicon surface as compared to plasma assisted deposition process and have better electrical performance. [ABSTRACT FROM AUTHOR]

Immobilized zeolit in alginate beads for adsorption of CO2was developed. Alginate immobilized zeolit beads was generated by dropping the mixture of Na-alginate and zeolite solution into Ca2+ solution. The adsorption efficacy such as the influence of contact time, mass of zeolite, flowrate of CO2, and mass of adsorbent was evaluated. The adsorption of CO2 onto alginate immobilized zeolit beads was investigated by performing both equilibrium and kinetic batch test. Bead was characterized by FTIR and SEM. Alginate immobilized zeolit beads demonstrated significantly higher sorption efficacy compared to plain alginate beads and zeolite with 0.25 mmol CO2 adsorbed /g adsorbent. Optimum condition was achieved with mass composition of alginate:zeolite (3:1), flowrate 50 mL/min for 20 minutes. The alginate immobilized zeolit beads showed that adsorption of CO2 followed Freundlich isotherm and pseudo second order kinetic model. Adsorption of CO2 onto alginate immobilized zeolite beads is a physisorption with adsorption energy of 6.37 kJ/mol. This results indicates that the alginate immobilized zeolit beads can be used as promising adsorbents for CO2. [ABSTRACT FROM AUTHOR]

We measured the spectral emission of plasmas from the National Spherical Tokamak Experiment in the extreme ultraviolet region, typically dominated by M-shell iron lines. Although we found that most of the significant emission in the 170-270 Å region emanates from iron, there are also some strong lines of carbon present. We show that the carbon lines are not produced by electron-impact excitation, and we speculate that they are formed instead by charge exchange. [ABSTRACT FROM AUTHOR]

The Core Imaging X-Ray Spectrometer (CIXS) will be employed for measurements of the ion temperature and of the toroidal rotation velocity, Ti and vφ, respectively, as a function of the radius of ITER plasmas. The diagnostic is based on precision determinations of the Doppler broadening, centroid shift, and intensity of the lines of highly ionized heavy impurities using a curved Bragg crystal spectral disperser and imager. The ions under consideration for the diagnostic are those of tungsten, krypton, xenon, iron, and argon. A detailed discussion is given of the need for atomic physics experiments and calculations involving the primary diagnostic lines and their collisional and dielectronic satellites. Such experiments and calculations define the instrument parameters, determine the diagnostic uncertainties, and provide paths for extending the diagnostic capabilities to measure impurity concentrations, electron temperature, and ion transport parameters. Enabling the diagnostic to measure radially dependent ion transport coefficients, in particular, requires a large amount of high-quality atomic data in the form of reliable excitation, ionization, and recombination rate coefficients as well as ionization balance calculations which make use of these data. Because core imaging spectrometers are being developed and implemented on present-day magnetic fusion devices, much of the atomic data are already needed and can be tested in the analysis of existing spectra recorded by these diagnostics. [ABSTRACT FROM AUTHOR]

We investigated the possibility of modelling structure-toxicity relationships by direct treatment of the molecular structure (without using descriptors) through an adaptive model able to retain the appropriate structural information. With respect to traditional descriptor-based approaches, this provides a more general and flexible way to tackle prediction problems that is particularly suitable when little or no background knowledge is available. Our method employs a tree-structured molecular representation, which is processed by a recursive neural network (RNN). To explore the realization of RNN modelling in toxicological problems, we employed a data set containing growth impairment concentrations (IGC50) for Tetrahymena pyriformis. [ABSTRACT FROM AUTHOR]

We analyze the HETGS Chandra and XMM-Newton X-ray spectrum of several type 1 AGNs (Active Galactic Nuclei) which harbor outflows: NGC3783, NGC3516, NGC7469, NGC5548, IRAS 13349+2438, and MCG -6-30-15. Absorption from almost all charge states of Fe are usually detected. This allows for a detailed reconstruction of the absorption measure distribution (AMD), which we define as the distribution of column density as a function of ionization parameter. We find a double peaked AMD for all the tested AGNs. All sources feature a deep minimum in column density consistent with no absorption from gas at temperatures of 4.5

A hard X-ray full field microscope from Xradia Inc. has been installed at SSRL on a 54-pole wiggler end station at beam line 6-2. It has been optimized to operate from 5–14 keV with resolution as high as 30 nm. High quality images are achieved using a vertical beam stabilizer and condenser scanner with high efficiency zone plates with 30 nm outermost zone width. The microscope has been used in Zernike phase contrast, available at 5.4 keV and 8 keV, as well as absorption contrast to image a variety of biological, environmental and materials samples. Calibration of the X-ray attenuation with crystalline apatite enabled quantification of bone density of plate-like and rod-like regions of mouse bone trabecula. 3D tomography of individual lacuna revealed the surrounding cell canaliculi and processes. 3D tomography of chiral branched PbSe nanowires showed orthogonal branches around a central nanowire. [ABSTRACT FROM AUTHOR]

In this study, a spectral analysis of the dwarf nova WX Hyi (which is a Cataclysmic Variables (CV)) is presented. The system was observed during the normal ourburst with the XMM-Newton observatory. X-ray bolometric flux value (EX<=12 keV) is estimated to be ∼2.98×10-12 erg cm-2 s-1 and X-ray luminosity LX = 5×1031 erg/s. Elemental abundance was founded 3 factor of solar abundances. If the gas temperature is higher than 107 K, it is optically thin. Therefore, they are radiated as thermal bremsstrahlung X-ray emission. PN+MOS detector measurements indicate that X-ray emitting maximum plasma temperature is kTMax = 31.3 keV (3.6322×108 K). Hence, the X-ray spectrum analysis during the normal outburst of WX Hyi is indicated a hot and optically thin plasma in the boundary layer that cools via an isobaric cooling flow while settling onto the white dwarf. For this temperature, the mass accretion rate is estimated to be MBL = 4×1014 gr/s (6.3×10-12 M⊙/yr). The ratio of the Boundary Layer (BL) (X-ray) luminosity to the disc luminosity was estimated to be LBL/Ldisc∼0.3. We calculated the mass accretion ratio of BL to the accretion disc (MBL/Mdisc) to be ∼0.74 and ∼0.27 during the rise to the outburst and outburst, respectively. A great quantity of the accreting gas from the rise to the outburst is lost in a wind. Fe XXV line at 6.7 keV is originated from a plasma having temperature of 107–108 K. The obtained temperature value from this study is compatible with this plasma structure. [ABSTRACT FROM AUTHOR]

My aim in this talk is to make clear that there are two sides to galaxy formation: the properties of the galaxies themselves, and the properties of the material that is left over from the galaxy formation process. To date, galaxy formation studies have focused on correctly predicting the properties of galaxies, and I will review the tremendous level of success in this area. However, these models usually ignore the “flip side” of galaxy formation: the intergalactic medium and the intra-group/intra-cluster medium (ICM). Yet, Chandra and XMM have given us a good view of the ICM and their results present an equally important challenge for theoretical models. I will show that this challenge is far from easy to meet, but describe the Bower et al. 2008 model of galaxy formation which successfully combines both sides of the observational constraints. [ABSTRACT FROM AUTHOR]

An advanced X-ray imaging crystal spectrometer is currently under development using a segmented position sensitive detector and time-to-digital converter (TDC) based delay-line readout electronics for burning plasma diagnostics. The proposed advanced XICS utilizes an eight-segmented position sensitive multi-wire proportional counter and supporting electronics to increase the spectrometer performance includes the photon count-rate capability and spatial resolution. [ABSTRACT FROM AUTHOR]

Unfavorable physicochemical properties often cause drug failures. It is therefore important to take lipophilicity and water solubility into account early on in lead discovery. This study presents log D7 models built using Gaussian Process regression, Support Vector Machines, decision trees and ridge regression algorithms based on 14556 drug discovery compounds of Bayer Schering Pharma. A blind test was conducted using 7013 new measurements from the last months. We also present independent evaluations using public data. Apart from accuracy, we discuss the quality of error bars that can be computed by Gaussian Process models, and ensemble and distance based techniques for the other modelling approaches. [ABSTRACT FROM AUTHOR]

An XMM-Newton observation of the bright QSO PG1211+143 was previously reported to show evidence for a massive, energetic outflow, with a velocity of v∼0.09c based on the identification of blue-shifted absorption lines detected in both EPIC and RGS spectra. Subsequently, an order-of-magnitude lower velocity has been claimed from an ion-by-ion model fit to the RGS data. We show here, from a re-analysis of the higher signal-to-noise EPIC data, that the high velocity is confirmed, with the resolution of additional absorption lines yielding a revised outflow velocity in the range ∼0.13–0.15c. Confirmation of a massive and energetic outflow in a non-BAL AGN has important implications for metal enrichment of the IGM and for the feedback mechanism implied by the correlation of black hole and galactic bulge masses. We note the near-Eddington luminosity of PG1211+143 may be the critical factor in driving such an energetic outflow, a situation likely to be common in AGN at higher redshift. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

X-ray grating spectra from Chandra and XMM-Newton have provided new insights into many of the physical processes present in astrophysical sources. For example, (i) shocks produced by magnetic accretion onto stellar surfaces cool as the material flows down, with density and temperature diagnostics providing tests of the accretion models; (ii) many active galactic nuclei (AGN) produce winds or outflows, detectable through X-ray absorption; (iii) active cool stars have coronal pressures several orders of magnitude larger than found on the Sun. The diagnostics used to determine temperatures, densities, elemental abundances, ionization states, and opacities require extremely accurate atomic data. At the same time, we must have a fairly complete database in order to ensure that the diagnostics are not blended or otherwise compromised. The best spectra are from bright objects with long exposures (days), but the information contained allows us to infer the location(s) of the emitting and absorbing plasmas and understand the physical properties. We will give examples to illustrate the role of atomic physics in our analyses of such spectra and the quality of data required. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

We provide a discussion of the density and photoexcitation sensitivity of the X-ray spectra of Fe L-shell ions (Fe XVII–Fe XXIV) calculated with the Livermore X-ray Spectral Synthesizer, a suite of IDL codes that calculates spectral models of highly charged ions based primarily on HULLAC atomic data. These models are applicable to collisionally ionized laboratory or cosmic plasmas with electron temperatures Te ≈ 2–45 MK (0.2–4 keV) and electron densities ne >= 1011 cm-3. Potentially useful density diagnostics are identified for Fe XVII and Fe XIX–Fe XXIII, with the most straightforward being the Fe XVII I(17.10 Å)/I(17.05 Å) line ratio and the Fe XXII I(11.92 Å)/I(11.77 Å) line ratio. Applying these models to the Chandra X-ray Observatory High Energy Transmission Grating spectrum of the intermediate polar EX Hya, we find that the strength of all the Fe L-shell lines are consistent with electron densities ne >= 1 × 1014 cm-3. Specifically, from the observed Fe XVII I(17.10 Å)/I(17.05 Å) line ratio, we infer an electron density n e >= 2 × 1014 cm-3 at the 3 σ level, while from the observed Fe XXII I(11.92 Å)/I(11.77 Å) line ratio, we infer ne = 1.0-0.5+2.0 × 1014 cm-3 at the 1 σ level and ne >= 2 × 1013 cm-3 at the 3 σ level. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

We review recent results from X-ray absorption line spectroscopy of diffuse hot gas in and around the Galaxy. Absorption lines of O VII, O VIII, and/or Ne IX have been detected in the spectra of LMC X-3 as well as three AGNs and seven Galactic low-mass X-ray binaries. We have implemented an analysis tool, accounting for line saturation and allowing for joint fits to multiple absorption lines. Our analysis gives no significant detection of the absorption beyond the distance of the LMC. The mean temperature and density of the X-ray-absorbing gas are ∼ 106.4 K and 3.6 × 10-3 cm-3, assuming a filling factor of ∼ 1 and a typical interstellar metallicity as well as a collisional ionization equilibrium. These assumptions seem to be consistent with constraints obtained from diffuse O VII emission and pulsar dispersion measure observations. The spatial distribution of the hot gas can be characterized by a hot gaseous disk with a scale height of only ∼ 1 kpc and an apparent density enhancement in the Galactic central region, consistent with the surface brightness distribution of the Galactic diffuse 3/4-keV background. The X-ray-absorbing species as well as those far-UV tracers such as O VI, N V, and C IV seem to follow a trend from high to low ionization states away from the Galactic plane. These results demonstrate the potential of X-ray absorption spectroscopy as a powerful tool in the study of the hot interstellar medium. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The ability of high resolution X-ray spectroscopy to directly probe the grain composition of the ISM is discussed. Using experimental data taken at the National Synchrotron Light Source at Brookhaven National Laboratory and the Advanced Photon Source at Argonne National Laboratory, current and near-future mission prospects for (1) distinguishing gas from dust phase absorption, and (2) determining the chemical composition of interstellar grains, through the details of X-ray absorption fine structure is assessed. Details, in-depth discussions and complete references can be found in Lee & Ravel 2005. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

At least half of all Active Galaxies show the presence of strong absorption features produced by highly ionized material. These features are blueshifted, implying outflowing winds. The location of these winds is of great importance to understanding the structure of quasars. Variability of the absorption features in response to flux variations of the central source is one of the best diagnostics to constrain the location and structure of AGN winds. Here we show that the opacity in the absorber in NGC 3783 clearly changes (at a level > 10σ) in a timescale of 31 days responding to a factor of ∼ 2 change in the ionizing continuum. There is also evidence for variability in the O VI K edge (at ∼ 3σ). The observed changes are consistent with the gas producing these absorption features being close to photoionization equilibrium. The observed change in opacity implies a density > 1 × 104 cm-3, and so locates the gas within 6 pc of the X-ray source. The scenario in which the gas is composed of a continuous radial range of ionization structures is ruled out, as in such scenario, no opacity variations are expected. Rather, the structure of the absorber is likely composed of heavily clumped gas. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

We give a brief review of what has been learned from high spectral resolution X-ray grating spectroscopy of type 1 active galaxies since the launch of Chandra and XMM-Newton. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

High-resolution X-ray spectroscopy of Active Galactic Nuclei has become possible thanks to the launch of XMM-Newton and Chandra with their grating spectrometers, and will be explored further after the expected launch of ASTRO-E2 with its XRS detector. In several AGN the X-ray spectra show the signatures of on outflowing, photo-ionised wind. Also several X-ray binaries show a similar imprint of a photo-ionised gas. The clearest signatures are formed by the broad range of absorption lines, mostly from the ground states of a wide range of ionisation states of the abundant elements. In addition to absorption lines due to the valence electrons, the spectra show many inner-shell absorption lines. Examples are the K-shell transitions of the most abundant metal, oxygen, in the 19–23 Å band, and 2p-3d transitions of lowly ionised iron in the 15–17 Å region. These transitions have an extremely important diagnostic value, as other transitions of the same ions frequently occur in the unobservable extreme ultraviolet. Several of these inner-shell transitions, however, lack accurate experimental or theoretical wavelengths, which makes the spectral analysis complicated and ambiguous. This is even more the case for transitions from metastable levels, which can be used as density diagnostics. Finally, attention is payed to the role of atomic data in the photo-ionisation equilibrium calculations. Uncertainties in for example dielectronic recombination rates cause large uncertainties in the predicted absorption line strengths. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

We describe an integrated software package for the calculation of various atomic radiative and collisional processes, including energy levels, radiative transition rates, collisional excitation and ionization by electron impact, photoionization, autoionization, and their respective inverse processes. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

Radiative transfer effects are capable of producing line spectra that differ markedly from those emitted from an optically-thin medium. Line photons that travel through an optically-thick medium may suffer multiple non-coherent scatterings, which can alter substantially the profiles of the emergent spectrum. Line transfer can also affect the emergent line intensities through destructive processes in which the energy is either re-radiated through other discrete transitions or is used in heating the ambient plasma. There are numerous astrophysical scenarios where transfer of X-ray lines may be relevant, including ionized surface layers of accretion disks, stellar winds in X-ray binaries, outflowing regions in active galactic nuclei, circumstellar environment of cosmic gamma-ray bursts, and even in the intergalactic medium of clusters of galaxies. Here, we focus on three specific transfer problems that are important for modeling and interpreting astrophysical X-ray spectra acquired with the grating spectrometers on board the Chandra and XMM-Newton observatories: (1) Compton scattering of emission lines, (2) fluorescent line emission from L-shell ions, and (3) overlap of two or more lines. We describe the relevant atomic processes, spectroscopic issues, and useful computational methods for solving these types of problems. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

We give a brief overview of recent simulation activities on the design of neutrino factories. Simulation work is ongoing on many aspects of a potential facility, including proton drivers, pion collection and decay channels, phase rotation, ionization cooling, and muon accelerators. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]