Line identification and lifetime measurements in the XUV and soft X-ray regions

A summary of the data acquired concerning line identification and lifetime measurements in the xuv and soft X-ray regions for a variety of both resonance transitions and forbidden transitions in ions of astrophysical interest is provided. Particular attention is called to a few papers which appeared in the Astrophysical Journal. These are of special relevance to specific astrophysical data needs. The many experiments completed in areas related to but somewhat outside the confines of the project title are mentioned

Sensitive X-ray Detectors Synthesised from CsPbBr3

The materials used in detection of high energy photons are of primary importance in the construction of efficient, cost effective and sensitive detectors. Current research into Perovskites for solar cell technology has stimulated interest in their potential alternative uses, one of which is in direct photon conversion radiation detectors, owed primarily to their high-Z elemental composition twinned with exceptional charge carrier transport properties. Here, the Perovskite CsPbBr 3 has been synthesised through solution growth. The raw CsPbBr 3 was a granular powder which was formed into disks of 8 mm diameter and 1-2 mm thickness by two methods: 1). the powders were pressed into pellets using a hydraulic press or 2). sealed in a quartz ampoule under vacuum and then melted and quenched to form a polycrystalline solid which was cut to size. Metallic contacts were deposited on the front and back faces to permit charge collection. The results from the pressed devices are promising, particularly given that the production method is cost effective, repeatable and scalable. The solid-from-melt devices show similar performance but further development is required to optimise the production method

High-Resolution Electron Time-of-Flight Apparatus for the Soft-X-Ray Region

A gas-phase time-of-flight (TOF) apparatus, capable of supporting as many as six electron-TOF analyzers viewing the same interaction region, has been developed to measure energy- and angle-resolved electrons with kinetic energies up to 5 keV. Each analyzer includes a newly designed lens system that can retard electrons to about 2% of their initial kinetic energy without significant loss of transmission; the analyzers can thus achieve a resolving power (E/ΔE) greater than 104 over a wide kinetic-energy range. Such high resolving power is comparable to the photon energy resolution of state-of-the-art synchrotron–radiation beamlines in the soft x-ray range, opening the TOF technique to numerous high-resolution applications. In addition, the angular placement of the analyzers, by design, permits detailed studies of nondipolar angular distribution effects in gas-phase photoemission

Compton double-to-single ionization ratio of helium at 57 keV

We have measured the Compton double-to-single ionization ratio of helium using an ion time-of-flight spectrometer along with monochromatized synchrotron radiation of 57 keV. This photon energy is high and probes the Compton ionization alone, since the photoionization makes only a negligible contribution to the total cross section. Comparing our result, which is (1.25±0.3)%, with theoretical calculations and measurements at lower energies shows that this energy is most likely still not high enough to confirm the value of the asymptotic high-energy limit experimentally

Relativistic Effects on Interchannel Coupling in Atomic Photoionization: The Photoelectron Angular Distribution of Xe

Measurements of the photoelectron angular-distribution asymmetry parameter β for Xe 5s photoionization have been performed in the 80–200 eV photon-energy region. The results show a substantial deviation from the nonrelativistic value of β=2 and provide a clear signature of significant relativistic effects in interchannel coupling

An exploration of the factors involved in lifestyle decisions in young people with cystic fibrosis using decision making vignettes, and the role of perceived risk in infection

This study explored the factors involved in lifestyle decision making in young people with Cystic Fibrosis, specifically the role of infection risk. Certain pathogens present a high risk of infection to people with Cystic Fibrosis, and can significantly affect their health. It is therefore important that people with the disease attempt to minimise the risk of contracting these infections. There was limited literature relating specifically to infection risk and decision making in this population. However, this study drew on decision making literature from other areas, with regard to engaging in risktaking behaviours. The study employed a vignette methodology, presenting a series of lifestyle situations to eight participants and asking them to think aloud whilst deciding whether to engage in the activity. This was followed by a brief interview. An interview was also conducted with a Consultant Microbiologist, offering a detailed understanding of the level of risk presented in each vignette. Thematic Analysis was used to interpret the results, highlighting a number of important themes. Participants frequently chose to engage in activities that would present an increased risk of infection. It was often important to find a balance between maintaining their health and engaging in a fulfilling life. However, at times, participants lacked an adequate understanding of the level of risk or the nature of the infections to make an informed decision. Implications for future research and clinical practice are discussed.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Beyond the Dipole Approximation: Angular-Distribution Effects in the 1s Photoemission from Small Molecules

Over the past two decades, the dipole approximation has facilitated a basic understanding of the photoionization process in atoms and molecules. Recent experiments on the 1s inner shells of small molecules at relatively low photon energies (⩽ 1000 eV) show strong nondipole effects. They are significant and measurable at energies close to threshold, in conflict with a common assumption that the dipole approximation is valid for photon energies below 1 keV

Large Nondipole Effects in the Angular Distributions of K-Shell Photoelectrons from Molecular Nitrogen

Measurements of angular distributions of K-shell electrons photoejected from molecular nitrogen are reported which reveal large deviations at relatively low photon energies ( ħω≤500eV) from emission patterns anticipated from the dipole approximation to interactions between radiation and matter. A concomitant theoretical analysis incorporating the effects of electromagnetic retardation attributes the observed large nondipole behaviors in N2 to bond-length-dependent terms in the E1⊗(E2,M1) photoelectron emission amplitudes which are indicative of a potentially universal nondipole behavior in molecular photoionization