1,583 research outputs found

    Radiation from Isolated Spectral Lines with Combined Doppler and Lorentz Broadening

    Get PDF
    Methods for the calculation of spectral absorption coefficients for combined Doppler and Lorentz broadening are summarized. The “curves of growth” have been extended to cover the ranges of parameters which arise in spectroscopic studies on flames

    Nomogram for the Evaluation of Blackbody Radiancy and of Peak and Total Intensities for Spectral Lines with Lorentz Contour

    Get PDF
    A nomogram has been constructed for the determination of blackbody radiancy and of peak and total intensities for spectral lines with Lorentz contour. The basic equations used for the construction of the nomogram and the use of the nomogram are described briefly

    Angular distributions of Îł rays from the 7Li(p,Îł) reaction at low energies

    Get PDF
    Angular distributions of the 14–17 MeV γ rays from the 7Li(p,γ) reaction at Ep=450, 402, and 80 keV were measured at 0°≤θlab≤135°, using a BGO detector and a 28-μg/cm2 LiF target. The angular distributions at Ep=450 and 402 keV agree with the previous results by Mainsbridge; at Ep=80 keV the ground-state transition is anisotropic on the order of 20%, confirming recent results by Chasteler et al

    Is There a Significant Difference Between the Results of the Coulomb Dissociation of 8B and the Direct Capture 7Be(p,g)8B Reaction?

    Full text link
    Recent claims of the Seattle group of evidence of "slope difference between CD [Coulomb Dissociation] and direct [capture] results" are based on wrong and selective data. When the RIKEN2 data are included correctly, and previously published Direct Capture (DC) data are also included, we observe only a 1.9 sigma difference in the extracted so called "scale independent slope (b)", considerably smaller than claimed by the Seattle group. The very parameterization used by the Seattle group to extract the so called b-slope parameter has no physical foundation. Considering the physical slope (S' = dS/dE), we observe a 1.0 sigma agreement between slopes (S') measured in CD and DC, refuting the need for new theoretical investigation. The claim that S17(0) values extracted from CD data are approximately 10% lower than DC results, is based on misunderstanding of the CD method. Considering all of the published CD S17(0) results, with adding back an unconfirmed E2 correction of the MSU data, yields very consistent S17(0) results that agree with recent DC measurements of the Seattle and Weizmann groups. The recent correction of the b-slope parameter (0.25 1/MeV) suggested by Esbensen, Bertsch and Snover was applied to the wrong b-slope parameter calculated by the Seattle group. When considering the correct slope of the RIKEN2 data, this correction in fact leads to a very small b-slope parameter (0.14 1/MeV), less than half the central value observed for DC data, refuting the need to correct the RIKEN2 data. In particular it confirms that the E2 contribution in the RIKEN2 data is negligible. The dispersion of measured S17(0) is mostly due to disagreement among individual DC experiments and not due to either experimental or theoretical aspects of CD.Comment: Reference 12 amended with an important communication from Dr. Bertsc

    Nomogram for the Evaluation of Blackbody Radiancy and of Peak and Total Intensities for Spectral Lines with Doppler Contour

    Get PDF
    A nomogram has been constructed for the determination of blackbody radiancy and of peak and total intensities for spectral lines with Doppler contour. The basic equations used for the construction of the nomogram and the use of the nomogram are described briefly. A method is outlined for determining absolute values of total intensities for spectral lines with combined Doppler and resonance contour by using the nomogram in conjunction with the “curves of growth.

    Boron Plus Deuteron Reactions

    Get PDF
    Gamma and alpha emission from the 15-Mev level of C12 is investigated in the reaction B11(d, n)C12*. An upper limit on the ratio of α- to γ-radiation from the state is Γα / Γγ6 Mev and Eγ=3.2 Mev following B12 decay. The cross section for the production of B12 is given as a function of bombarding energy for 0.5<~Ed<~3.25 Mev

    Constraining ^(26)Al+p resonances using ^(26)Al(^3He,d)^(27)Si

    Get PDF
    The ^(26)Al(^3He,d)^(27)Si reaction was measured from 0°≤θ_(c.m.)≤35° at E(^3He)=20 MeV using a quadrupole-dipole-dipole-dipole magnetic spectrometer. States in ^(27)Si were observed above the background at 7652 and 7741 keV and upper limits were set for the state at 7592 keV. Implications for the ^(26)Al(p,γ)^(27)Si stellar reaction rate are discussed

    Low-lying continuum structures in B8 and Li8 in a microscopic model

    Full text link
    We search for low-lying resonances in the B8 and Li8 nuclei using a microscopic cluster model and a variational scattering method, which is analytically continued to complex energies. After fine-tuning the nucleon-nucleon interaction to get the known 1+ state of B8 at the right energy, we reproduce the known spectra of the studied nuclei. In addition, our model predicts a 1+ state at 1.3 MeV in B8, relative to the Be7+p threshold, whose corresponding pair is situated right at the Li7+n threshold in Li8. Lacking any experimental evidence for the existence of such states, it is presently uncertain whether these structures really exist or they are spurious resonances in our model. We demonstrate that the predicted state in B8, if it exists, would have important consequences for the understanding of the astrophysically important Be7(p,gamma)B8 reaction.Comment: 6 pages with 1 figure. The postscript file and more information are available at http://nova.elte.hu/~csot

    A study of nuclei of astrophysical interest in the continuum shell model

    Full text link
    We present here the first application of realistic shell model (SM) including coupling between many-particle (quasi-)bound states and the continuum of one-particle scattering states to the spectroscopy of 8B and to the calculation of astrophysical factors in the reaction 7Be(p,gamma)8B.Comment: 9 pages incl. 3 figures, LaTeX with iopart class and epsf. Invited talk at the Int. Workshop on Physics with Radioactive Nuclear Beams, Jan. 12-17, 1998, Puri, India. Shortened version will be published in proceedings to apear as a separate J. Phys. G volum

    Abortion provision in Northern Ireland: the views of health professionals working in obstetrics and gynaecology units

    Get PDF
    Introduction: Abortion became decriminalised in Northern Ireland in October 2019. Until that point there existed no evidence concerning the views of health professionals on decriminalisation or on their willingness to be involved in abortion care. The purpose of this study was to address this lack of evidence, including all categories of health professionals working in obstetrics and gynaecology units in Northern Ireland. Methods: The online survey was targeted at medical, nursing and midwifery staff working in the obstetrics and gynaecology units in each Health and Social Care (HSC) Trust in Northern Ireland. The survey was issued via clinical directors in each Trust using the REDCap platform. Results: The findings showed widespread support for decriminalisation of abortion up until 24 weeks’ gestation (n=169, 54%). The majority of clinicians stated they were willing to provide abortions in certain circumstances (which were undefined) (n=188, 60% medical abortions; n=157, 50% surgical abortions). Despite regional variation, the results show that there are sufficient numbers of clinicians to provide a service within each HSC Trust. The results indicate that many clinicians who report a religious affiliation are also supportive of decriminalisation (n=46, 51% Catholic; n=53, 45% Protestant) and are willing to provide care, countering the assumption that those of faith would all raise conscientious objections to service provision. Conclusions: The findings of this study are very encouraging for the development, implementation and delivery of local abortion care within HSC Trusts in Northern Ireland and should be of value in informing commissioners and providers about the design of a service model and its underpinning training programmes
    • …
    corecore