Development of large diameter T-111 /Ta-8W-2Hf/ tubing Final report

Large diameter T-111 tubing processed from seamless and welded tube shell

A bright metastable atom source at 80 K

We describe a high flux source of cold (80 K) metastable helium atoms. The source employs a direct current nozzle discharge which produces in excess of 10¹⁵ atoms/steradian/s. Liquid nitrogen cooling of the discharge source yields atomic velocities below 900 ms⁻¹. Such a source has practical applications for experiments concerned with laser cooling and trapping of metastable helium atoms

Photodetachment study of He^- quartet resonances below the He(n=3) thresholds

The photodetachment cross section of He^- has been measured in the photon energy range 2.9 eV to 3.3 eV in order to investigate doubly excited states. Measurements were made channel specific by selectively detecting the residual He atoms left in a particular excited state following detachment. Three Feshbach resonances were found in the He(1s2p ^3P)+e^-(epsilon p) partial cross section: a ^4S resonance below the He(1s3s ^3S) threshold and two ^4P resonances below the He(1s3p ^3P) threshold. The measured energies of these doubly excited states are 2.959260(6) eV, 3.072(7) eV and 3.26487(4) eV. The corresponding widths are found to be 0.20(2) meV, 50(5) meV and 0.61(5) meV. The measured energies agree well with recent theoretical predictions for the 1s3s4s ^4S, 1s3p^2 ^4P and 1s3p4p ^4P states, respectively, but the widths deviate noticeably from calculations for 1s3p^2 ^4P and 1s3p4p ^4P states.Comment: 10 pages, 3 figures, LaTeX2e scrartcl, amsmath. Accepted by Journal of Physics B; minor changes after referee repor

The use of protocol in breaking bad news: evidence and ethos

This article discusses health professionals use of protocol in the breaking of bad news, focusing particularly on the well-known SPIKES framework. The evidence of impact on the patient experience is examined and recommendations are made for further outcome-based research. Existing evidence suggests that the model as commonly interpreted may not fully meet the needs of patients or reflect the clinical experience of breaking bad news for some professionals and further guidance may be needed to support them in their practice. The ethos of the step-wise protocol is debated, questioning whether it helps or hinders individualised care and the formation of a genuine relationship between patient and professional. Finally, recommendations for practice are offered

Angle-resolving time-of-flight electron spectrometer for near-threshold precision measurements of differential cross sections of electron-impact excitation of atoms and molecules

This article presents a new type of low-energy crossed-beam electron spectrometer for measuring angular differential cross sections of electron-impact excitation of atomic and molecular targets. Designed for investigations at energies close to excitation thresholds, the spectrometer combines a pulsed electron beam with the time-of-flight technique to distinguish between scattering channels. A large-area, position-sensitive detector is used to offset the low average scattering rate resulting from the pulsing duty cycle, without sacrificing angular resolution. A total energy resolution better than 150 meV (full width at half maximum) at scattered energies of 0.5-3 eV is achieved by monochromating the electron beam prior to pulsing it. The results of a precision measurement of the differential cross section for electron-impact excitation of helium, at an energy of 22 eV, are used to assess the sensitivity and resolution of the spectrometer.M.L. would also like to thank both the Australian Research Council and the Deutsche Forschungsgemeinschaft, who have supported the project under Grant Nos. LX0346836 and LA 1473, respectively

Positron interactions with water-total elastic, total inelastic, and elastic differential cross section measurements

9 págs.; 5 figs.; 4 tabs.© 2014 AIP Publishing LLC. Utilising a high-resolution, trap-based positron beam, we have measured both elastic and inelastic scattering of positrons from water vapour. The measurements comprise differential elastic, total elastic, and total inelastic (not including positronium formation) absolute cross sections. The energy range investigated is from 1 eV to 60 eV. Comparison with theory is made with both R-Matrix and distorted wave calculations, and with our own application of the Independent Atom Model for positron interactions.This work has been supported by the Australian Research Council’s Centre of Excellence Program. G.G. and F.B. would like to acknowledge the Spanish Ministerio de Economıa y Competitividad (project FIS2012-31230). Some financial support through COST Action “Nano-IBCT” is also gratefully acknowledged.Peer Reviewe

Elastic electron scattering from 3-hydroxytetrahydrofuran: experimental and theoretical studies

We report the results of measurements and calculations for elastic electron scattering from 3-hydroxytetrahydrofuran (C4H8O2). The measurements are performed with a crossed electron-target beam apparatus and the absolute cross-sections are determined using the relative flow technique. The calculations are carried out using the Schwinger multichannel method in the static-exchange plus polarization (SEP) approximation. A set of angular differential cross-sections (DCS) is provided at five incident energies (6.5, 8, 10, 15 and 20 eV) over an angular range of 20–130°, and the energy dependence of the elastic DCS at a scattering angle of 120° is also presented. Integral elastic and elastic momentum transfer cross-sections have also been derived and calculated. The results are compared with those of recent measurements and calculations for the structurally similar molecule tetrahydrofuran (C4H8O)

Cross Sections for Electron-induced Resonant Vibrational Excitations in Polyatomic Molecules

We continue our review of experimental data for electron-polyatomic molecule collisions in connection with fusion and processing plasmas, as well as with the associated environmental issues. In this case we focus on vibrational excitation processes, in particular what vibrational modes can be identified in electron energy loss experiments and which of these modes are resonantly enhanced due to the temporary capture of the incident electron by the species in question. In this latter respect we report indicative excitation function data, all of which were originally measured at Sophia University and for which the differential cross section, for excitation of the relevant mode, are studied as a function of the incident electron energy at a fixed scattered electron angle. Unlike our previous compilation (NIFS?DATA?101) for elastic scattering, which was conducted over a broad range of energies (1?100 eV), vibrational excitation cross sections usually only become significant when the resonance enhancement process occurs. As a consequence, this survey encompasses incident electron energies between 1?30 eV. Consistent with our first report, no detailed comparison is made here with any other data that might be available in the literature. This course of action was once again adopted in order to keep this report to a sensible length

A joint theoretical and experimental study for elastic electron scattering from 1,4-dioxane

We present results of measurements and calculations of elastic electron scattering from 1,4-dioxane in the energy range of 0–1000 eV. Absolute differential and integral elastic cross sections have been measured using a crossed electron-molecule beam spectrometer and the relative flow technique, at four energies in the 10–30 eV range and for scattered electrons in the angular range 20°–129°. The measured cross sections are compared with results from R-matrix computations, at the static exchange plus polarization level, calculated at energies between 0–20 eV, and with calculations employing the independent atom model with the screening corrected additivity rule (IAM-SCAR). Those latter computations were conducted at energies between 1 and 1000 eV. Agreement between the measured and R-matrix cross sections was typically found to be good at all common energies, whereas agreement with IAM-SCAR was satisfactory only at 30 eV. To the best of our knowledge, the present results are the first absolute data to be published in the literature for this scattering system