The isotope effect in the electronic structure factors of liquid NH3 and ND3

1995 ◽  
Vol 73 (11-12) ◽  
pp. 735-740 ◽  
Author(s):  
S. Takeda ◽  
P. A. Egelstaff
Keyword(s):  
Electronic Structure ◽  
Gamma Rays ◽  
Correlation Functions ◽  
Gamma Ray ◽  
Liquid Structure ◽  
Density Correlation ◽  
Structure Factors ◽  
Radioisotope Source ◽  
The Difference ◽  
Absorption Technique

Gamma rays from a radioisotope source, 241Am, were scattered from samples of liquid light ammonia (NH3) and heavy ammonia (ND3) at temperatures of 294.5 and 284.5 K under their normal vapour pressures to determine the electronic liquid structure factors. In addition the densities of these samples were checked by the gamma ray absorption technique. From the difference between the total electronic structure factors of liquid NH3 and ND3, the difference of the r-space electronic correlation functions of the two liquids (at the same temperature) was evaluated. The observable difference is due (mainly) to quantum effects in the intermolecular electron-density correlation functions of liquid ammonia, which will be discussed.

Gamma rays in the MeV region at balloon altitude

1968 ◽  
Vol 46 (10) ◽  
pp. S494-S497 ◽  
Author(s):  
K. Okudaira ◽  
Y. Hirasima
Keyword(s):  
Gamma Rays ◽  
Main Part ◽  
Counting Rate ◽  
Gamma Ray ◽  
Plastic Scintillator ◽  
Scintillation Counter ◽  
Lower Atmosphere ◽  
Upper Limit ◽  
Extraterrestrial Origin ◽  
The Difference

Gamma rays in the MeV region were observed from balloons at λ = 26 °N on September 29, 1966. A scintillation counter constructed with two NaI ⅓ in. × 2 in. [Formula: see text] crystals separated by 1 cm × 2 in. [Formula: see text] lead was used to measure the directional distribution of the gamma-ray flux. This counter was flown at an atmospheric depth of 14.2 g cm−2. As the response of each crystal of this counter depends on the direction of incidence of the gamma rays, an anisotropic distribution of gamma rays gives rise to a difference between the counting rates of two crystals. It was ascertained from the observation that albedo gamma rays from the lower atmosphere are predominant at this high altitude. The deviation from the calculated values of the difference in counting rate assuming only atmospheric gamma rays may be due to an extraterrestrial origin of part of the gamma-ray flux. For the measurement of the gamma-ray spectrum, a phoswich counter (1 in. × 1 in. [Formula: see text] NaI crystal surrounded by ¼-in.-thick plastic scintillator) was flown to 10 g cm−2. Though the main part of the gamma-ray flux is probably due to atmospheric gamma rays, an upper limit for the isotropic cosmic gamma-ray flux is deduced to be (1.25 ± 0.05) × 10−2 counts cm−2 s−1 sr−1 MeV−1 in the energy range 1.2–3.1 MeV.

GAMMA-RAY TRANSITIONS IN 15O AND 15N

1965 ◽  
Vol 43 (12) ◽  
pp. 2310-2318 ◽  
Author(s):  
T. K. Alexander ◽  
A. E. Litherland ◽  
C. Broude
Keyword(s):  
Excited States ◽  
Gamma Rays ◽  
Doppler Shift ◽  
Gamma Ray ◽  
Measured Energy ◽  
The Mean ◽  
The Difference ◽  
Mean Lifetimes

The gamma rays from the first two excited states of 15O and 15N populated by the 14N + d, T(16O, αγ)15N, and 16O(3He, αγ)15O reactions have been observed with a Ge(Li) spectrometer. The measured energy separations are 50 ± 5 keV for the 15O doublet and 28.5 ± 3 keV for the 15N doublet. The difference between the 5.24-MeV gamma ray from 15O and the 5.27-MeV gamma ray from 15N is 29 ± 1 keV. From Doppler-shift and broadening measurements of the energies of the gamma rays from the T(16O, αγ)15N and 16O(3He, αγ)15O reactions, information on the mean lifetimes of the states was obtained. The mean lifetimes of the 5.30-and 5.27-MeV states of 15N are 4.3 ± 1.8 × 10−14 sec and > 10−12 sec respectively. The mean lifetimes of the 5.19- and 5.24-MeV states of 15O are < 3 × 10−13 sec and > 10−12 sec respectively.

The performances of M4 generation of Mentik Susu rice mutants irradiated with gamma-ray

2020 ◽  
Vol 21 (9) ◽  
Author(s):  
Wafa’ Nur Hanifah ◽  
Parjanto PARJANTO ◽  
Sri Hartati ◽  
Ahmad Yunus
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Design Experiment ◽  
High Productivity ◽  
Central Java ◽  
Gamma Ray Irradiation ◽  
Long Life ◽  
The Difference ◽  
Short Stems ◽  
And Control

Abstract. Hanifah WN, Parjanto, Hartati S, Yunus A. 2020. The performances of m4 generation of Mentik Susu rice mutants irradiated with gamma-ray. Biodiversitas 21: 4041-4046. Mentik Susu is local rice from Magelang, Central Java, Indonesia. It has superiority, in terms of soft texture and white color, but on the other hand, this local rice has the disadvantage of having relatively high stems, low yield, and long life. One way to overcome the weakness of Mentik Susu rice is by mutating plants using gamma-rays. The purpose of this research was to study M4 mutants from Mentik Susu rice irradiated with gamma-ray and to select mutans that have short stem and high productivity. The study was conducted using a simple random design experiment by planting various strains of M4 generation of Mentik Susu rice irradiated with 100 Gy and 200 Gy gamma-rays. T-test was employed to test the difference between strains treated with gamma-ray irradiation and control samples (without gamma-ray irradiation). The results showed that the M4 Mentik Susu rice irradiated with 100 Gy and 200 Gy gamma-rays in overall had lower stems, shorter flowering and harvesting ages, and higher productivity than non-irradiated Mentik Susu rice (control). The strains with the shortest stem and with highest yield productivity was resulted from 200 Gy gamma-ray irradiation with code of M-MS200-G15T3-2. This study also selected 30 individual mutant plants that had short stems and high productivity, suggesting that these plants can be passed to M5 generation.

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.

Sign in / Sign up

Export Citation Format

Share Document