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2 edition of Constraints on the low-energy E1 cross section of 12C (alpha, gamma) 16(O) from the beta-delayed alpha spectrum of 16N. found in the catalog.

Constraints on the low-energy E1 cross section of 12C (alpha, gamma) 16(O) from the beta-delayed alpha spectrum of 16N.

James David Powell

Constraints on the low-energy E1 cross section of 12C (alpha, gamma) 16(O) from the beta-delayed alpha spectrum of 16N.

by James David Powell

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  • 10 Currently reading

Published .
Written in English

    Subjects:
  • Physics Theses

  • Edition Notes

    Thesis (Ph.D.), Dept. of Physics, University of Toronto

    ContributionsAzuman, R. E. (supervisor)
    The Physical Object
    Pagination153 p.
    Number of Pages153
    ID Numbers
    Open LibraryOL20601131M

    Most embeddings of the Standard Model into a more unified theory, in particular those based on supergravity or superstrings, predict the existence of a hidden sector of particles that have only very weak interactions with visible-sector Standard Model particles. Some of these exotic particle candidates [for instance, axions, axion-like particles, and hidden (1) gauge bosons] may be very light. The analyzing power data was used to determine relative E1 and M 1 strengths of the photodisintegration cross section. In the new measurement, we plan to utilize linearly polarized LCS photons and fast (liquid scintillator) and slow (3He + polyethylene) neutron detectors to determine absolute strengths of M 1 and E1 cross sections from neutron.

    Determining the E1/M1 polarization of the Low-energy Enhancement in the gamma-ray Strength Function of 56Fe: 7: 8. Fusion cross section measurements of 16C+12C and 16C+13C near the Coulomb barrier (5) Neutron-capture cross section constraints in neutron-rich Sn and Sb isotopes: 9: D. Hoff: Reaction Mechanism for Large. For decades, the unnaturalness of the weak scale has been the dominant problem motivating new particle physics, and weak-scale supersymmetry has been the dominant proposed solution. This paradigm is now being challenged by a wealth of experimental data. In this review, we begin by recalling the theoretical motivations for weak-scale supersymmetry, including the gauge hierarchy problem, .

    We review the main low-energy effects that are expected in this framework. We discuss the current observational constraints on such a framework, focusing on those achievable through high-energy astrophysics observations. Differential cross section as a function of π0 production angle for 12C, together with the fit for Primakoff (red dashed. A double ionization chamber was used in finding the complete kinetic energy distribution of U/sup / fragments produced by Mev neutron fission The obtained data were plotted and compared to the data on the kinetic energy distribution of fragments from the U/sup / fission by Mev neutrons and to the calculated dispersion It was found that E and DELTA E have the highest magnitudes.


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Constraints on the low-energy E1 cross section of 12C (alpha, gamma) 16(O) from the beta-delayed alpha spectrum of 16N by James David Powell Download PDF EPUB FB2

Constraints on the low-energy E1 cross section of^{12} C (α, γ)^{16} O from the β-delayed α spectrum of^{16} N [Phys. Rev. C 50, ()] Article (PDF Available) in Physical Review C 56(3. Constraints on the low-energy E1 cross section of 12C(alpha, gamma)16O from the beta -delayed alpha spectrum of 16N.

Azuma RE, Buchmann L, Barker FC, Barnes CA, D'Auria JM, Dombsky M, Giesen U, Jackson KP, King JD, Korteling RG, McNeely P, Cited by: Constraints on the low-energy E1 cross section of 12C(alpha, gamma)16O from the beta -delayed alpha spectrum of 16N Article (PDF Available) in Physical Review C 50(2).

Title: Comment on Constraints on the Low-Energy E1 Cross Section of 12C(alpha,gamma)16O from the Beta-Delayed Alpha Spectrum of 16N. Authors: Ralph H. France III, Moshe Gai (Submitted on 31 Jullast revised 11 Sep (this version, v2))Author: Moshe Gai.

In addition to obtaining the α spectrum, this procedure determines the complete detector response including the low-energy tail. The spectrum, which contains more than events, has been fitted by R- and K-matrix parametrizations which include the measured 12C(α,γ)16O cross section and the measured α+12C elastic scattering phase shifts.

Comment on Constraints on the Low-Energy E1 Cross Section of 12C(alpha,gamma)16O from the Beta-Delayed Alpha Spectrum of 16N. By Ralph H. France III and Moshe Gai. Abstract. We compute quadrupole transition probabilities between low-energy 16O states, and the 12C(α,γ)16O E2 cross sections to the ground and 21+ states.

At keV, we find an S factor equal to MeV b. The cross section for the reaction 12C(α, γ)16O has been measured for a range of c.m. energies extending from MeV to MeV, by using 12C targets of high isotopic purity, large NaI(T1.

Wang's 29 research works with citations and reads, including: Constraints on the low-energy E1 cross section of^{12} C (α, γ)^{16} O from the β-delayed α spectrum of^{16} N [Phys. E1andE2 capture cross section and astrophysical reaction rate of the key reaction 12 C(α,γ) 16 O J.W. Hammer a, a, R.

Kunz a, b,heff b, F. Haas c, d, M. Assun¸c˜ao b, c,i-Pelissie b, b,a b,n c, F. Fleurot e,poulos f, b, F. Hammache g,opulos f, A. Korichi b,i´c a. L. Buchmann and U. Giesen, private communication. tudy of the 12C(a, 7)1aO cross section. CONCLUSIONS From the fl-delayed a-spectrum measurements discussed above, and earlier 12C(a,'y) and 12C(a,a)12C data, we have derived much more precise values of SE1() for the 12C(a, 'y)x~O reaction than previously available: 79 i 21 keV-b for R.

Because the geometry is close to an angle inte- grated one the cross section is assumed to be angle integrated. Finally, Ref. [13] reports a measurement of the 12C(a,7) cross section using six germanium detectors, an a-beam and ~2C implanted targets.

Sixteen angular distributions at a variety of energies between E=l.4 MeV and MeV are. The key reaction 12 C (α, γ) 16 O in nuclear astrophysics is difficult to be performed experimentally at low energy because of the Coulomb barrier. But it is different if we use its inverse reaction 16 O (γ, α) 12 C because the cross-section of 16 O (γ, α) 12 C is almost times larger than the cross-section of 12 C (α, γ) 16 O at the same center of mass energy (E c.

The cross section – usually expressed as the astrophysical S factor – of the reaction 12 C(α, γ) 16 O (Q = MeV) is dominated by E1 and E2 capture processes into the 16 O ground state. The two multipoles appear to be of similar importance and arise predominately from the high-energy tails of two subthreshold resonances at E = − 45 (J π = 1 −) and − keV (2 +), 1 and their.

Azuma, R. and Buchmann, L. and Barker, F. et al. () Constraints on the low-energy E1 cross section of 12C(α,γ)16O from the β-delayed α spectrum of 16N. Physical Review C, 50 (2). ISSN The analysis of all the available E1 cross sections with the K-matrix method and with a three-level R-matrix method yields a consistent prediction of 79±16 keV b for the E1 S factor at keV.

Constraints on the low-energy E-1 cross section of C (alpha, gamma) O from the beta-delayed alpha spectrum of N On the sensitivity of. E1 and E2 capture cross section and astrophysical reaction rate of the key reaction 12C(α,γ) Constraints on the 12C The low-energy 7Be(p, γ)8B cross section from an R-matrix approach journal, June Barker, F.

Nuclear Physics A, Vol.Issue 3. )very small cross section)data for E>1 MeV only Betelgeuse [Dupree, Gilliland, Hubble ST, NASA, ESA, ] Theoretical extrapolation to low energy: necessary but di cult because pand dsubthreshold bound statesenhance cross section but are not well known Jean-Marc Sparenberg (ULB) Analysis of low-energy 12C+ scattering University of Surrey Cross Section.

Current tabulations of μ/ρ rely heavily on theoretical values for the total cross section per atom, ς tot, which is related to μ/ρ according to: (1) In (eq 1), u (= 2 × ) is the atomic mass unit (1/12 of the mass of an atom of the nuclide 12C)4.

Cross Section Measurements of the 7Be(n,p)7Li and the 7Be(n,α)4He Reactions Covering the Big-Bang Nucleosynthesis Energy Range by the Trojan Horse Method at CRIB Pages Hayakawa, S. (et al.). Direct capture cross section and low-energy resonances in the 22Ne(p,gamma)23Na reaction (in session "Nuclear Astrophysics") Pushing the 12C+12C cross-section to the limits with the STELLA experiment at IPN Orsay (in session "Nuclear Astrophysics") On the nature of the low-energy E1 strength in the unstable nucleus 68Ni (in session.Isospin selection rules suppress the E1 component of the ground state cross section, creating a unique situation where the E1 and E2 contributions are of nearly equal amplitudes.

Constraints on the low-energy E-1 cross section of C (alpha, gamma) O from the beta-delayed alpha spectrum of N Low-energy cross-section measurement.The level scheme of Tb has been extended up to MeV excitation energy and spin I=67/2 using the Sn(31 P,4n) reaction.

Evidence for a new octupole band built upon an excited multi-particle-hole state has been found. The high spin levels are interpreted in the framework of DIPM model and presents an evolution towards sizeable oblate shape at the highest spins.