scholarly journals Directional Correlations of Gamma Rays in the Decay of 36 hr 82Br

1968 ◽  
Vol 21 (5) ◽  
pp. 649 ◽  
Author(s):  
SL Gupta ◽  
MM Bajaj
Keyword(s):  
Gamma Rays ◽  
Single Particle ◽  
Spin Assignment ◽  
First Time ◽  
Rotor Model ◽  
Unique Spin

Coincidence and gamma-gamma directional correlation measurements are made for the 10 cascades of s2Kr: 1648-777, 1008-1044, 1317-777, 619-1475, 555-1317,555-619,828-1044,828-(1044)-777,698-777, and 619-698 keV, of which the cascade 1008-1044 keV has been attempted for the first time. The results permit a unique spin assignment of 5 for the 2829 ke V level from the directional correlation of the 1008-1044 keV cascade and a spin of 3 to the level at 2425 keV from that of the 1648-777 keV cascade. Multipole character and admixture are determined for the transitions 1648, 1475, 1044, 1008, 555, 828, 698, 619, and 1317 keV. Computed E2 partial half-lives for the last two transitions are compared with the predictions of the single-particle estimate and the nonaxial rotor model.

scholarly journals SPIN LIGHT OF NEUTRINO IN GRAVITATIONAL FIELDS

2005 ◽  
Vol 14 (02) ◽  
pp. 309-321 ◽  
Author(s):  
MAXIM DVORNIKOV ◽  
ALEXANDER GRIGORIEV ◽  
ALEXANDER STUDENIKIN
Keyword(s):  
Black Hole ◽  
Gamma Rays ◽  
Dense Matter ◽  
Total Power ◽  
Fourth Power ◽  
Gravitational Fields ◽  
Quasiclassical Theory ◽  
Relativistic Jet ◽  
First Time ◽  
Gamma Factor

We develop the quasiclassical theory of a massive neutrino spin evolution in the presence of gravitational fields, and the corresponding probability of the neutrino spin oscillations in gravitational fields is derived for the first time. On this basis we also predict a new mechanism for electromagnetic radiation by a neutrino moving in the vicinity of gravitating objects (the "spin light of neutrino," SLν, in gravitational fields). It is shown that the total power of this radiation is proportional to the neutrino gamma factor to the fourth power, and the emitted photon energy, for the case of an ultra relativistic neutrino, spans up to gamma-rays. We investigate the SLν caused by both gravitational and electromagnetic fields, also accounting for effects of arbitrary moving and polarized matter, in various astrophysical environments. In particular, we discuss the SLν emitted by a neutrino moving in the vicinity of a rotating neutron star, black hole surrounded by dense matter, as well as by a neutrino propagating in the relativistic jet from a quasar.

scholarly journals Channeling and radiation experiments at SLAC

2019 ◽  
Vol 34 (34) ◽  
pp. 1943006
Author(s):  
U. Wienands ◽  
S. Gessner ◽  
M. J. Hogan ◽  
T. Markiewicz ◽  
T. Smith ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Beam Energy ◽  
Narrow Band ◽  
Test Facility ◽  
Test Beam ◽  
High Beam ◽  
Silicon Crystals ◽  
Volume Reflection ◽  
Series Of Experiments ◽  
First Time

Since 2014, a SLAC-Aarhus-Ferrara-CalPoly collaboration augmented by members of ANL and MIT has performed electron and positron channeling experiments using bent silicon crystals at the SLAC End Station A Test Beam as well as the FACET accelerator test facility. These experiments have revealed a remarkable channeling efficiency of about 24% under our conditions. Volume reflection is even more efficient with almost the whole beam taking part in the reflection process. A positron experiment demonstrated quasi-channeling oscillations for the first time at high beam energy. In our most recent experiment we measured the spectrum of gamma radiation for crystal orientations covering channeling and volume reflection. This series of experiments supports the development of more advanced crystalline devices capable e.g. of producing narrow-band gamma rays with electron beams or studying the interaction of the electrons with the wakefields generated in the crystal at high beam intensity.

scholarly journals Laser illumination-induced dramatic catalytic activity change on Au nanospheres

2019 ◽  
Vol 10 (22) ◽  
pp. 5793-5800 ◽  
Author(s):  
Zhongju Ye ◽  
Lin Wei ◽  
Lehui Xiao ◽  
Jianfang Wang
Keyword(s):  
Catalytic Activity ◽  
Symmetry Breaking ◽  
Gold Nanoparticle ◽  
Single Particle ◽  
Catalytic Properties ◽  
Activity Change ◽  
Laser Illumination ◽  
Single Particle Level ◽  
Particle Level ◽  
First Time

In this work, the distinct catalytic properties of a single gold nanoparticle (GNP) after symmetry breaking were disclosed at the single-particle level for the first time.

Using a clinical linac to determine the energies of gamma-ray transitions and half-lives of barium nuclei

2020 ◽  
Vol 35 (10) ◽  
pp. 2050062
Author(s):  
Abdullah Engin Çalık ◽  
Kaan Manisa ◽  
Ahmet Biçer ◽  
Mehmet Erdoğan ◽  
Mürsel Şen ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Linear Accelerator ◽  
Nuclear Physics ◽  
Hpge Detector ◽  
Gamma Ray ◽  
Energy Levels ◽  
Photonuclear Reactions ◽  
High Purity Germanium ◽  
Physics Experiment ◽  
First Time

Photonuclear reactions have great importance in understanding the structure of the nuclei. These reactions, performed using the gamma rays obtained by way of bremsstrahlung, are a standard nuclear physics experiment. In this study, a non-enriched barium sample was activated for the first time by using a clinical linear accelerator (cLINACs). The spectrum of barium radioisotopes was obtained by using a gamma spectrometry with a high purity germanium (HPGe) detector. The obtained spectroscopic data were analyzed and energy levels and half-life values together with their uncertainties were obtained. Some energy levels and half-lives of [Formula: see text]Ba were determined with more precision than those of literature values.

Gamma-ray production in the 170Er(p,n)170Tm nuclear reaction

Open Physics ◽  
2010 ◽  
Vol 8 (4) ◽  
Author(s):  
Alexandru Mihailescu ◽  
Gheorghe Cata-Danil
Keyword(s):  
High Resolution ◽  
Energy Range ◽  
Nuclear Reaction ◽  
Gamma Rays ◽  
Compound Nucleus ◽  
Beam Energy ◽  
Gamma Ray ◽  
Excitation Functions ◽  
Γ Ray ◽  
First Time

AbstractFor the first time discrete gamma-rays following the nuclear reaction 170Er(p,n)170Tm with enriched target were measured with a high resolution GeHP spectrometer. Protons delivered by the Bucharest FN Tandem Van de Graaff accelerator bombarded a thin self-supporting film of enriched erbium. Measured γ-ray energies (Eγ), their relative intensities (Iγ) and corresponding excitation functions for the beam energy range 2.0–3.6 MeV are reported in the present work. The measured excitation functions were fairly well reproduced by compound nucleus calculations based on the Hauser-Feshbach formalism.

The Decay of 169Yb

1972 ◽  
Vol 50 (19) ◽  
pp. 2348-2354 ◽  
Author(s):  
S. K. Sen ◽  
D. L. Salie ◽  
E. Tomchuk
Keyword(s):  
Direct Measurement ◽  
Gamma Rays ◽  
Internal Conversion ◽  
Gamma Ray ◽  
Conversion Coefficient ◽  
Coulomb Excitation ◽  
Internal Conversion Coefficient ◽  
Electron Capture Decay ◽  
Upper Limits ◽  
First Time

The decay of 169Yb was investigated using several Ge(Li) detectors of different sizes. The following gamma rays (energies in keV and intensities within brackets) were definitely identified with the 169Yb decay: 20.7 (0.66 ± 0.04), 63.1 (124 ± 5), 93.6 (7.2 ± 0.3), 109.8 (50 ± 2), 117.3 (0.08 ± 0.04), 118.2 (5.4 ± 0.2), 130.5 (34 ± 2), 156.7 (0.023 ± 0.004), 177.2(59 ± 3), 198.0 (100), 240.4 (0.33 ± 0.02), 261.0 (4.7 ± 0.2), and 307.7 (28 ± 1). The recently reported weak gamma-ray peaks at 515 (0.008 ± 0.002) and 625 (0.010 ± 0.002) were also observed and could not be ruled out as not belonging to 169Yb. The recently reported gamma-ray peaks at 140, 160, 207, 288, 295, 316, 320, 328, 355, 371, 379, 396, and 417 were detected and shown not to be from the decay of 169Yb while those at 218, 229, 285, 304, 335, 388, 411, and 425 were not observed and upper limits were placed on their intensities. The presence of very weak peaks at 515 and 625 establishes the formation of the 633 keV state of 169Tm following electron capture decay of 169Yb as reported by George. (This level has been previously observed only in Coulomb excitation of 169Tm.) The total internal conversion coefficient for the 20.7 keV transition was determined for the first time from the direct measurement of the gamma-ray intensity as 51 ± 10 corresponding to an M1 transition.

STUDY OF SINGLE-PARTICLE RESONANT STATES

2004 ◽  
Vol 19 (20) ◽  
pp. 1537-1545 ◽  
Author(s):  
SHISHENG ZHANG
Keyword(s):  
Single Particle ◽  
Effective Interaction ◽  
Random Phase ◽  
Mean Field ◽  
Coupling Constant ◽  
Relativistic Mean Field ◽  
Resonant States ◽  
Scattering Phase ◽  
First Time ◽  
Phase Shift Method

Energies and widths for single-particle resonant states in the continuum in 120 Sn , as the necessary input quantities of relativistic random phase approximation for the investigation of isoscalar giant octupole resonance, are determined by analytic continuation in the coupling constant (ACCC) method within the framework of self-consistent relativistic mean field (RMF) theory for the first time. For the effective interaction NL3, the results in this scheme agree well with those of scattering phase shift method on the basis of RMF. Similar calculations are carried out in neutron-rich nucleus 84 Ni .

scholarly journals A study of the effective atomic number of SixPb0.7-x(Fe2O3)0.3 ternary alloys for photons

2016 ◽  
Vol 31 (4) ◽  
pp. 327-334
Author(s):  
Mehmet Buyukyildiz ◽  
Murat Kurudirek
Keyword(s):  
Atomic Number ◽  
Gamma Rays ◽  
Interpolation Method ◽  
Effective Atomic Number ◽  
Polynomial Equation ◽  
Ternary Alloys ◽  
Photon Scattering ◽  
Photon Attenuation ◽  
Scattering Ratio ◽  
First Time

The effective atomic number (Zeff) of SixPb0.7-x(Fe2O3)0.3 ternary alloys was obtained for photons. Rayleigh to Compton scattering ratio (R/C) has been determined to obtain the Zeff of SixPb0.7-x(Fe2O3)0.3 ternary alloys of varying Si and Pb (10 %-60 %) content for scattering of 59.54 keV g-rays at an angle of 130?. The theoretical R/C ratios of elements were plotted as a function of the atomic number and fitted to a polynomial equation. Experimental R/C values of alloys were then used to obtain Zeff using this fit equation. Also, Zeff values of these alloys were determined for the first time by interpolating the R/C of the material using the R/C data of adjacent elements in between the R/C of the alloy lies. The agreement between the interpolation method and the fit equation was quite satisfactory. The obtained Zeff for photon scattering were then compared to the Zeff for total photon attenuation obtained using the Auto-Zeff program. Significant variations were observed between the Zeff for scattering and the total attenuation of gamma rays.

scholarly journals Observational signatures of gamma-rays from bright blazars and wakefield theory

2020 ◽  
Vol 493 (2) ◽  
pp. 2229-2237 ◽  
Author(s):  
N E Canac ◽  
K N Abazajian ◽  
T Tajima ◽  
T Ebisuzaki ◽  
S Horiuchi
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Accretion Disc ◽  
Spectral Energy ◽  
Energy Distributions ◽  
Wakefield Acceleration ◽  
Inverse Compton ◽  
Time Variations ◽  
First Time ◽  
Over Time

ABSTRACT Gamma-ray observations have revealed strong variability in blazar luminosities in the gamma-ray band over time-scales as short as minutes. We show, for the first time, that the correlation of the spectrum with intensity is consistent with the behaviour of the luminosity variation of blazar spectral energy distributions (SEDs) along a blazar sequence for low synchrotron peak blazars. We show that the observational signatures of variability with flux are consistent with wakefield acceleration of electrons initiated by instabilities in the blazar accretion disc. This mechanism reproduces the observed time variations as short as 100 s. The wakefield mechanism also predicts a reduction of the electron spectral index with increased gamma-ray luminosity, which could be detected in higher energy observations well above the inverse Compton peak.

Conversion-electron and gamma–gamma directional correlation measurements in 134Ba

1990 ◽  
Vol 68 (12) ◽  
pp. 1479-1485 ◽  
Author(s):  
Bakhshish Chand ◽  
Jatinder Goswamy ◽  
Devinder Mehta ◽  
Nirmal Singh ◽  
P. N. Trehan
Keyword(s):  
Conversion Electron ◽  
Hpge Detector ◽  
Transition Probability ◽  
Energy Levels ◽  
Electron Spectrometer ◽  
Conversion Electrons ◽  
Conversion Coefficients ◽  
First Time ◽  
Rotor Model

Conversion electrons from the decay of 134Cs have been investigated using a mini-orange electron spectrometer. The electron intensities for the K-conversion of 242.7 keV and L, (M + N … ) conversion of 563.2, 795.9, 801.9, 1038.6, 1167.9, and 1365.2 keV transitions in 134Ba are being reported for the first time. The conversion-electron data have been further used to determine the conversion coefficients for various transitions in, 34Ba. Also, the gamma–gamma directional correlation measurements for seven cascades in 134Ba have been carried out using a HPGe–HPGe detector coincidence setup. The multipole admixtures for the 475.3, 563.2, 569.3, 795.9, 801.9, 1038.6, and 1365.2 keV transitions have been deduced from these measurements. A multipole admixture of M1 + 37% E2 has been obtained for the 1038.6 keV transition in 134Ba. The reduced transition probability ratios for the transitions de-exciting second 2+ and 3+ energy levels in 134Ba have been calculated and compared with the values predicted by the triaxial rotor model for γ = 28.5°. This indicates the softness of the, 134Ba nucleus toward γ deformation.

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