COINCIDENCE STUDIES OF THE DECAY OF INDIUM 114

1954 ◽  
Vol 32 (1) ◽  
pp. 35-48 ◽  
Author(s):  
M. W. Johns ◽  
C. C. McMullen ◽  
R. J. Donnelly ◽  
S. V. Nablo
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Branching Ratio ◽  
Coincidence Circuit ◽  
Capture Process ◽  
End Point ◽  
Inner Bremsstrahlung ◽  
Positron Spectrum

A coincidence circuit of resolving time 3 × 10−9 sec. has been used to examine the decay of In114. Coincidence experiments are described to show that of the five gamma-rays which follow the K-capture process the 0.722 and 1.300 Mev. radiations are both in cascade with the 0.556 Mev. gamma-ray and that the spins and parities of the excited levels of energy 0.556, 1.278, and 1.856 Mev. in Cd114 are 2 +, 2 +, and 0 +, respectively. The observed beta–gamma coincidences may be ascribed to a combination of inner bremsstrahlung associated with the strong 2 Mev. β− transition and a weak β− group of intensity less than 1 × 10−3 beta per disintegration and end point about 0.8 Mev. The positron spectrum has a branching ratio of 4 ± 1 × 10−5 and an end point between 1.0 and 1.4 Mev.

DISCOVERY OF Pr137

1958 ◽  
Vol 36 (11) ◽  
pp. 1483-1486 ◽  
Author(s):  
Carl Dahlstrom ◽  
J. S. Foster ◽  
A. L. Thompson
Keyword(s):  
Gamma Rays ◽  
Half Life ◽  
Chemical Separation ◽  
Mass Determination ◽  
Proton Bombardment ◽  
End Point ◽  
Neutron Deficient Isotope ◽  
Positron Spectrum

The neutron-deficient isotope Pr137 has been discovered by proton bombardment of natural cerium, chemical separation, and mass determination. Its half-life is 1.5 ± 0.1 hours and the end point of its positron spectrum is 1.7 ± 0.1 Mev. No gamma rays were observed.

STUDIES IN THE DECAY OF THE ACTIVE DEPOSIT OF ACTINIUM: III. LEVELS IN 211Bi AND ITS DAUGHTER PRODUCTS

1967 ◽  
Vol 45 (7) ◽  
pp. 2295-2313 ◽  
Author(s):  
W. F. Davidson ◽  
C. R. Cothern ◽  
R. D. Connor
Keyword(s):  
Solid State ◽  
Gamma Rays ◽  
Level Scheme ◽  
Decay Scheme ◽  
Gamma Ray ◽  
Branching Ratio ◽  
Upper Limits ◽  
Single Transition ◽  
Detailed Level

Previous work on the decay of 211Pb has been developed and extended using lithium-drifted germanium detectors and sum–coincidence techniques. A more detailed level scheme for 211Bi has been produced with greater precision in the determination of the energies and intensities of the 16 gamma rays observed.The alpha decays of 211Bi and 211Po have been studied using solid-state detectors with a resolution of 15.5 keV at 6 MeV. The alpha branching of 211Bi to the 350-keV level in 207Tl has been found to be 16.43 ± 0.04% and that of 211Po to the 570-keV level in 207Bi to be 0.50 ± 0.07%. The beta–alpha branching ratio in the decay of 211Bi is 0.274 ± 0.004%. The data enable upper limits to be placed on any other alpha groups in the active deposit in the energy range 3–13 MeV.The gamma-ray spectrum of separated sources of 207Tl has been found to consist of a single transition of energy 898 ± 0.5 keV with an intensity of 0.002 4 ± 0.000 4 photons per 207Tl decay or 0.002 9 ± 0.000 4 photons per 211Pb decay.A decay scheme for the entire active deposit is given.

Lifetimes in 32S

1970 ◽  
Vol 48 (1) ◽  
pp. 47-55 ◽  
Author(s):  
R. W. Ollerhead ◽  
T. K. Alexander ◽  
O. Häusser
Keyword(s):  
Gamma Rays ◽  
Ground State ◽  
Doppler Shift ◽  
State Transition ◽  
Gamma Ray ◽  
Branching Ratio ◽  
Dipole Transition ◽  
Average Lifetime ◽  
Line Shapes ◽  
Doppler Shift Attenuation

Lifetimes have been measured for five levels in 32S. The levels were populated by inelastic scattering of protons, and the gamma rays were detected at angles between 0° and 127° using a 40 cm3 Ge(Li) detector mounted inside a split annular NaI(Tl) crystal. The spectrometer was used simultaneously as both an escape-suppressed and a three-crystal pair spectrometer. Decay schemes and lifetimes have been determined using thick targets of PbS, MoS2, and sulfur cooled to 77 °K. Lifetime information was obtained both from analysis of the observed gamma-ray line shapes and from analysis of the Doppler shift attenuation in the different target materials. The two methods of analysis agree within the errors. A weak ground-state transition was observed from the J = 3 level at 5.012 MeV, establishing its parity as negative. Analysis of the line shape observed at 0° and the Doppler shift attenuation gave an average lifetime of 7.5 ± 0.5 × 10−13 s. The observed branching ratio (4 ± 0.4% to the ground state) implies an E3 enhancement of 20 ± 2.4 Weisskopf units (W.u.). A similar analysis gave a lifetime of 4.9 ± 0.9 × 10−13 s for the J = 1 level at 4.699 MeV, which implies that the dipole transition to the ground state is highly retarded. Lifetimes have also been measured for levels at 3.780 MeV [Formula: see text], 4.288 MeV (7.4 ± 0.6 × 10−14 s), and 5410 MeV (1.9 ± 0.2 × 10−13 s); the transition strengths are tabulated and discussed.

On the possible gamma-ray source in Cygnus

1967 ◽  
Vol 31 ◽  
pp. 469-471
Author(s):  
J. G. Duthie ◽  
M. P. Savedoff ◽  
R. Cobb
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Right Ascension

A source of gamma rays has been found at right ascension 20h15m, declination +35°, with an uncertainty of 6° in each coordinate. Its flux is (1·5 ± 0·8) x 10-4photons cm-2sec-1at 100 MeV. Possible identifications are reviewed, but no conclusion is reached. The mechanism producing the radiation is also uncertain.

Solar Flare Energetic Neutral Emission Measurements in the Project Coronas-I

1994 ◽  
Vol 144 ◽  
pp. 635-639
Author(s):  
J. Baláž ◽  
A. V. Dmitriev ◽  
M. A. Kovalevskaya ◽  
K. Kudela ◽  
S. N. Kuznetsov ◽  
...  
Keyword(s):  
Solar Flare ◽  
Energy Range ◽  
Gamma Rays ◽  
Pulse Shape ◽  
Gamma Ray ◽  
Pulse Shape Discrimination ◽  
Shape Discrimination ◽  
Solar Neutron ◽  
Low Altitude

AbstractThe experiment SONG (SOlar Neutron and Gamma rays) for the low altitude satellite CORONAS-I is described. The instrument is capable to provide gamma-ray line and continuum detection in the energy range 0.1 – 100 MeV as well as detection of neutrons with energies above 30 MeV. As a by-product, the electrons in the range 11 – 108 MeV will be measured too. The pulse shape discrimination technique (PSD) is used.

scholarly journals On a Possible Origin of the Gamma-ray Excess around the Galactic Center

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1432
Author(s):  
Dmitry O. Chernyshov ◽  
Andrei E. Egorov ◽  
Vladimir A. Dogiel ◽  
Alexei V. Ivlev
Keyword(s):  
Dark Matter ◽  
Gamma Rays ◽  
Molecular Clouds ◽  
Alternative Explanation ◽  
Gamma Ray ◽  
Galactic Center ◽  
The Self ◽  
Large Area ◽  
Mhd Turbulence ◽  
The Standard Model

Recent observations of gamma rays with the Fermi Large Area Telescope (LAT) in the direction of the inner galaxy revealed a mysterious excess of GeV. Its intensity is significantly above predictions of the standard model of cosmic rays (CRs) generation and propagation with a peak in the spectrum around a few GeV. Popular interpretations of this excess are that it is due to either spherically distributed annihilating dark matter (DM) or an abnormal population of millisecond pulsars. We suggest an alternative explanation of the excess through the CR interactions with molecular clouds in the Galactic Center (GC) region. We assumed that the excess could be imitated by the emission of molecular clouds with depleted density of CRs with energies below ∼10 GeV inside. A novelty of our work is in detailed elaboration of the depletion mechanism of CRs with the mentioned energies through the “barrier” near the cloud edge formed by the self-excited MHD turbulence. This depletion of CRs inside the clouds may be a reason for the deficit of gamma rays from the Central Molecular Zone (CMZ) at energies below a few GeV. This in turn changes the ratio between various emission components at those energies and may potentially absorb the GeV excess by a simple renormalization of key components.

scholarly journals GAMMA RAY - INDUCED MITOTIC ABNORMALITIES IN Helianthus annuus L. VARIETY EKIZ 1 / LOS RAYOS DE GAMMA CAUSA ANORMALIDADES MITOTICAS EN Helianthus annuus L. VARIEDAD DE EKIZ 1 / LES ANORMALITÉS MITOTIQUES CHARGÉÉS DES RAYONS GAMMA

Helia ◽  
2001 ◽  
Vol 24 (35) ◽  
pp. 39-46
Author(s):  
Orhan Arslan ◽  
Şenol Bal ◽  
Nilgün Venice ◽  
Semra Mirici
Keyword(s):  
Helianthus Annuus ◽  
Mitotic Index ◽  
Gamma Rays ◽  
Metaphase Chromosome ◽  
Gamma Ray ◽  
Dose Increase ◽  
Helianthus Annuus L ◽  
Mitotic Abnormalities ◽  
Chromosome Stickiness

SUMMARYIn this study, mitotic effects of gamma rays on Ekiz 1 variety belonging to Helianthus annuus L. (2n= 34) in the M0 (first irradiated seeds), M1 and M2 generations have been investigated. Seeds (M0) were irradiated with gamma rays at 10, 20, 30, 40 and 50 kR doses. Percentage of total abnormalities in the M0, M1 and M2 generations increased parallel to the increasing dose of radiation. These abnormalites have been observed as C-metaphase, chromosome stickiness, laggards and bridges with or without fragment. Mitotic index (M.I.) in the M0, M1 and M2 generations has decreased parallel to the dose increase. When the generations are compared, both the amounts of decrease in mitotic index and in the percentage of mitotic abnormalities were mostly observed in M0.

scholarly journals Modeling Gamma-Ray SEDs and Angular Extensions of Extreme TeV Blazars from Intergalactic Proton-Initiated Cascades in Contemporary Astrophysical EGMF Models

Universe ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 220
Author(s):  
Emil Khalikov
Keyword(s):  
Gamma Rays ◽  
Large Scale ◽  
Gamma Ray ◽  
High Energy ◽  
Cascade Model ◽  
Point Sources ◽  
Spectral Energy ◽  
Observation Data ◽  
Cherenkov Telescopes ◽  
The Universe

The intrinsic spectra of some distant blazars known as “extreme TeV blazars” have shown a hint at an anomalous hardening in the TeV energy region. Several extragalactic propagation models have been proposed to explain this possible excess transparency of the Universe to gamma-rays starting from a model which assumes the existence of so-called axion-like particles (ALPs) and the new process of gamma-ALP oscillations. Alternative models suppose that some of the observable gamma-rays are produced in the intergalactic cascades. This work focuses on investigating the spectral and angular features of one of the cascade models, the Intergalactic Hadronic Cascade Model (IHCM) in the contemporary astrophysical models of Extragalactic Magnetic Field (EGMF). For IHCM, EGMF largely determines the deflection of primary cosmic rays and electrons of intergalactic cascades and, thus, is of vital importance. Contemporary Hackstein models are considered in this paper and compared to the model of Dolag. The models assumed are based on simulations of the local part of large-scale structure of the Universe and differ in the assumptions for the seed field. This work provides spectral energy distributions (SEDs) and angular extensions of two extreme TeV blazars, 1ES 0229+200 and 1ES 0414+009. It is demonstrated that observable SEDs inside a typical point spread function of imaging atmospheric Cherenkov telescopes (IACTs) for IHCM would exhibit a characteristic high-energy attenuation compared to the ones obtained in hadronic models that do not consider EGMF, which makes it possible to distinguish among these models. At the same time, the spectra for IHCM models would have longer high energy tails than some available spectra for the ALP models and the universal spectra for the Electromagnetic Cascade Model (ECM). The analysis of the IHCM observable angular extensions shows that the sources would likely be identified by most IACTs not as point sources but rather as extended ones. These spectra could later be compared with future observation data of such instruments as Cherenkov Telescope Array (CTA) and LHAASO.

THE DECAY OF Pm149

1960 ◽  
Vol 38 (12) ◽  
pp. 1577-1585 ◽  
Author(s):  
Agda Artna ◽  
Margaret E. Law
Keyword(s):  
High Resolution ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Conversion Coefficient ◽  
Beta Spectrum ◽  
Multichannel Analyzer ◽  
Coincidence Spectrometer ◽  
Beta Spectrometer ◽  
Beta Group

The 52.8-hour activity of Pm149 has been investigated using a high resolution beta spectrometer, a lens type coincidence spectrometer, and a scintillation spectrometer in conjunction with a multichannel analyzer. The beta spectrum was found to consist of two groups with maximum energies of 1.072 ± 0.002 Mev and 0.786 ± 0.004 Mev, and intensities of 97.1 ± 0.4% and 2.9 ± 0.4% respectively. A gamma ray of energy 285.7 ± 0.3 kev was found to be in coincidence with the 0.786-Mev beta group. No other gamma rays with intensities greater than 0.1% were found. The K conversion coefficient for the 286-kev transition was measured to be 0.075 ± 0.008. This together with the values of 6.5 ± 0.7 and 4 ± 1 obtained for the K/L and L/M conversion ratios respectively indicate that this transition is M1 in character with less than 10% E2 admixture.

scholarly journals Radio jets and gamma-ray emission in radio-silent narrow-line Seyfert 1 galaxies

2018 ◽  
Vol 614 ◽  
pp. L1 ◽  
Author(s):  
A. Lähteenmäki ◽  
E. Järvelä ◽  
V. Ramakrishnan ◽  
M. Tornikoski ◽  
J. Tammi ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
Spiral Galaxies ◽  
Narrow Line ◽  
Radio Jets ◽  
Relativistic Jet ◽  
Gamma Ray Emission

We have detected six narrow-line Seyfert 1 (NLS1) galaxies at 37 GHz that were previously classified as radio silent and two that were classified as radio quiet. These detections reveal the presumption that NLS1 galaxies labelled radio quiet or radio silent and hosted by spiral galaxies are unable to launch jets to be incorrect. The detections are a plausible indicator of the presence of a powerful, most likely relativistic jet because this intensity of emission at 37 GHz cannot be explained by, for example, radiation from supernova remnants. Additionally, one of the detected NLS1 galaxies is a newly discovered source of gamma rays and three others are candidates for future detections.

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