Design and calibration of a source and a polarimeter for polarized 14.4 keV Mössbauer gamma rays

1980 ◽  
Vol 58 (7) ◽  
pp. 1010-1018 ◽  
Author(s):  
J. M. Daniels ◽  
H. Y. Lam ◽  
P. L. Li
Keyword(s):  
Single Crystal ◽  
Gamma Rays ◽  
Γ Rays

A source of polarized 14.4 keV Mössbauer γ rays, using a magnetized foil, and a polarizer using a single crystal of siderite, are described. The procedures for determining the polarization of the γ rays, and for calibrating and using the polarimeter, are described in detail.

scholarly journals The internal conversion of gamma-rays.—Part II

1928 ◽  
Vol 121 (787) ◽  
pp. 447-456
Keyword(s):  
Magnetic Field ◽  
Quantum Mechanics ◽  
Wave Equation ◽  
Gamma Rays ◽  
Internal Conversion ◽  
Scalar Potential ◽  
X Ray ◽  
Electro Magnetic Field ◽  
Γ Rays ◽  
Electro Magnetic

In a previous paper the absorption of γ-rays in the K-X-ray levels of the atom in which they are emitted was calculated according to the Quantum Mechanics, supposing the γ-rays to be emitted from a doublet of moment f ( t ) at the centre of the atom. The non-relativity wave equation derived from the relativity wave equation for an electron of charge — ε moving in an electro-magnetic field of vector potential K and scalar potential V is h 2 ∇ 2 ϕ + 2μ ( ih ∂/∂ t + εV + ih ε/μ c (K. grad)) ϕ = 0. (1) Suppose, however, that K involves the space co-ordinates. Then, (K. grad) ϕ ≠ (grad . K) ϕ , and the expression (K . grad) ϕ is not Hermitic. Equation (1) cannot therefore be the correct non-relativity wave equation for a single electron in an electron agnetic field, and we must substitute h 2 ∇ 2 ϕ + 2μ ( ih ∂/∂ t + εV) ϕ + ih ε/ c ((K. grad) ϕ + (grad. K) ϕ ) = 0. (2)

Gamma rays and high-energy neutrons in the atmosphere

1968 ◽  
Vol 46 (10) ◽  
pp. S1030-S1033 ◽  
Author(s):  
M. V. K. Apparao ◽  
R. R. Daniel ◽  
George Joseph ◽  
G. S. Gokhale ◽  
P. J. Lavakare ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Counting Rate ◽  
Plastic Scintillator ◽  
Pulse Height ◽  
Growth Curves ◽  
High Energy ◽  
Cutoff Rigidity ◽  
Energy Formula ◽  
Γ Rays ◽  
Γ Ray

In continuation of our earlier experiments studying the emission of solar neutrons, we have now developed detector systems which respond to γ rays of energy 1–5 MeV and neutrons of energy [Formula: see text]. The two detectors are almost identical. Each consists of a CsI (Na) crystal (B) of diameter 3.8 cm, completely enclosed in a tapered cylinder of plastic scintillator (A) operated in anticoincidence; the crystals have thicknesses of 2.4 and 1.2 cm respectively. A balloon carrying these detectors was flown on March 16, 1967 over Hyderabad, India (vertical cutoff rigidity 16.9 GV) and floated at a ceiling altitude of 6.0 mb for 1 hour. In addition to γ-ray and neutron events (AB), events A and AB were also continuously monitored throughout the flight. Pulses corresponding to 1–5 MeV in the 2.4-cm crystal (γ rays) and 6–40 MeV in the 1.2-cm crystal (high-energy neutrons) were analyzed by a 64-channel pulse-height analyzer. On the basis of the pulse-height distributions and γ-ray efficiencies in the two crystals, we attribute events of 1–5 MeV energy from the thicker crystal to γ rays and those > 10 MeV in energy from the thinner one to stars produced by high-energy neutrons [Formula: see text] in the crystal. Atmospheric growth curves for γ rays and neutrons have been obtained; these growth curves as well as those for events A and AB show the normal features of the Pfotzer maximum, steady decreases up to the ceiling altitude, and a constant counting rate at ceiling. The atmospheric counting rates at ceiling altitude give for γ rays of energy 1–5 MeV a flux of ~1 photon per cm2 s and for neutrons of energy [Formula: see text] a flux of ~0.1 neutron per cm2 s. No evidence for a solar component in either channel was found.

scholarly journals Gamma Rays from Cosmic Rays

1981 ◽  
Vol 94 ◽  
pp. 309-319 ◽  
Author(s):  
A. W. Wolfendale
Keyword(s):  
Cosmic Rays ◽  
Gamma Rays ◽  
Molecular Clouds ◽  
Cosmic Ray ◽  
Cosmic Ray Intensity ◽  
Cosmic Ray Interactions ◽  
The Galaxy ◽  
Γ Rays ◽  
Γ Ray

It is shown that there is evidence favouring molecular clouds being sources of γ-rays, the fluxes being consistent with expectation for ambient cosmic rays interacting with the gas in the clouds for the clouds considered. An estimate is made of the fraction of the apparently diffuse γ-ray flux which comes from cosmic ray interactions in the I.S.M. as distinct from unresolved discrete sources. Finally, an examination is made of the possibility of gradients of cosmic ray intensity in the Galaxy.

scholarly journals Very high energy gamma-rays from flat spectrum radio quasars

2014 ◽  
Vol 10 (S313) ◽  
pp. 27-32
Author(s):  
Elina Lindfors
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
High Energy ◽  
High Energy Gamma ◽  
Spectrum Radio ◽  
Very High Energy ◽  
Energy Gamma ◽  
Emission Models ◽  
Γ Rays ◽  
Very High

AbstractThe detection of Flat Spectrum Radio Quasars (FSRQs) in the Very High Energy (VHE, E>100 GeV) range is challenging, mainly because of their steep soft spectra and distance. Nevertheless four FSRQs are now known to be VHE emitters. The detection of the VHE γ-rays has challenged the emission models of these sources. The sources are also found to exhibit very different behavior. I will give an overview of what is known about the VHE emission of these sources and about the multiwavelength signatures that are connected to the VHE gamma-ray emission.

Diffraction of Mössbauer Gamma Rays in Single Crystal Magnetite

1977 ◽  
Vol 16 (9) ◽  
pp. 1713-1714 ◽  
Author(s):  
Nobuyuki Hayashi ◽  
Isao Sakamoto
Keyword(s):  
Single Crystal ◽  
Gamma Rays

NEUTRON CAPTURE GAMMA RAYS FROM LITHIUM, BORON, AND NITROGEN

1957 ◽  
Vol 35 (12) ◽  
pp. 1347-1360 ◽  
Author(s):  
G. A. Bartholomew ◽  
P. J. Campion
Keyword(s):  
Thermal Neutron ◽  
Gamma Rays ◽  
Cross Sections ◽  
Neutron Capture ◽  
Radiative Capture ◽  
Capture Cross ◽  
Γ Rays ◽  
Capture Cross Sections

The neutron capture γ-rays from Li7, B11, and N15 have been studied. In Li7 γ-rays are observed at 7.26 ± 0.03 Mev. and 6.78 ± 0.05 Mev. In B11 six γ-rays are detected. The spectrum is consistent with J = 7/2 + for the capturing state. In N15 six previously unreported γ-rays are detected. Estimates of thermal neutron radiative capture cross sections are: Li6, 0.028 ± 0.008 b.; B10, 0.5 ± 0.2 b.; and N14, 0.08 ± 0.02 b.

scholarly journals Nanoparticles for active combination radio mitigating agents of Zinc Coumarate and Zinc Caffeiate in a rat model

2021 ◽  
Author(s):  
Mostafa A. Askar ◽  
Mona S. Guida ◽  
Seham. M. AbuNour ◽  
Essam A. Ragab ◽  
Eiman N. Ali ◽  
...  
Keyword(s):  
Body Weight ◽  
Gamma Rays ◽  
Hematological Parameters ◽  
The Body ◽  
Histopathological Study ◽  
Biological Processes ◽  
T Helper ◽  
Γ Rays ◽  
Cd4 Cell ◽  
Morphological State

Abstract Zinc Coumarate and zinc caffeiatenano-particles (ZCoNPs, ZCaNPs) have been shown to affectthe different biological processes. This work was undertaken to evaluate the mitigating action of ZCoNPs in combination with ZCaNPsagainst liver damage induced by gamma rays (γ-rays). Rats were exposed to 7Gy of γ-rays, and theninjected intraperitoneally (i.p.) with ZCoNPs [2U / rat / day (5 mg/kg)], and ZCaNPs [2U / rat / day (15 mg/kg)] for 7 consecutive days.The results showed that irradiated rats treated with ZCoNPs (5 mg/kg/body weight) in combination with ZCaNPs (15 mg/kg/body weight) for 7 days revealed a significant increase in the body weight, antioxidants levels, T Helper (CD4) Cell and T Cytotoxic (CD8), associated with amarked decrease in the level of lipid peroxidation (LP), nitric oxide(NOx), total free radicals concentrate (TFRC), and DNA fragmentation. Moreover, positive alterations in the morphological state, hematological parameters, and thecell cycle phases were noticed. Additionally, the histopathological study demonstrated an improvement in the liver tissue of irradiated rats after treatment.Thus, ZCoNPs and ZCaNPscould be usedas a natural mitigating agent to reduce the hazards of ionizing radiation.

A HIGH RESOLUTION FLAT CRYSTAL SPECTROMETER FOR NEUTRON CAPTURE γ-RAY STUDIES

1959 ◽  
Vol 37 (2) ◽  
pp. 203-231 ◽  
Author(s):  
J. W. Knowles
Keyword(s):  
Single Crystal ◽  
Neutron Capture ◽  
Counting Efficiency ◽  
Double Crystal ◽  
Γ Rays ◽  
Γ Ray ◽  
Antiparallel Position ◽  
Crystal Arrangement ◽  
Good Agreement ◽  
Soller Slit

A flat crystal diffraction spectrometer, constructed for the measurement of γ-rays resulting from neutron capture, is discussed both experimentally and theoretically. The spectrometer is used either as a single crystal or a double crystal instrument. In the single crystal arrangement a Laue diffracted γ-ray beam from a broad source proceeds through a Soller slit which gives it a 45-second angular divergence, to a sodium iodide scintillation detector. The energy is determined by the angle between the Soller slit and the crystal. The resolution is determined by the Soller slit, and is 4% at 1 Mev when diffracting from the (440) planes of a single germanium crystal. In the two-crystal configuration a γ-ray which is Laue diffracted from the first crystal is further diffracted from a second crystal set in the antiparallel position. The angle between the reflecting planes of the two crystals determines the γ-ray energy. The Soller slit serves only as shielding for the detector in this arrangement. The resolution depends upon the mosaics and thicknesses of the crystals; it is 0.4% at 1 Mev for diffraction from the (211) planes of two calcite crystals, each 23 mm thick and of 1.7- and 0.9-second mosaics respectively. The range of measurement extends from 80 kev to greater than 5 Mev. Where other values of γ-ray energies exist, agreement to within the expected precision, ± 0.2% is obtained. The counting efficiency as a function of energy depends on the integrated reflectivities of the crystals which may be determined at the time of a γ-ray measurement by means of the double crystal arrangement. The integrated reflectivity as a function of energy has been calculated for a number of crystals of known mosaic and throughout the range of measurement, from 0.2 to 5 Mev, good agreement is obtained.

THE MEASUREMENT OF EXTRA HARD X-RAYS AND GAMMA RAYS IN ROENTGENS

1937 ◽  
Vol 15a (5) ◽  
pp. 67-78 ◽  
Author(s):  
G. C. Laurence
Keyword(s):  
Gamma Rays ◽  
Unit Volume ◽  
Absolute Intensity ◽  
X Rays ◽  
Standard Temperature ◽  
Ionization Current ◽  
Γ Rays ◽  
Wall Materials ◽  
Temperature And Pressure

The intensity in roentgens per second of X-rays or γ-rays harder than 0.03 Å may be measured with a small thimble chamber with homogeneous walls of elements below atomic number 13 and thick enough to be impermeable to the fastest secondary β-rays. The ionization current measured under saturation conditions at standard temperature and pressure is divided by BV, and correction is made for the apparent absorption of the X-rays m the walls. V is the volume of the chamber and B is given by[Formula: see text]A table (Table IV) of the values of 2 loge (Zw/Za) for different wall materials is given, and J, K, and L are plotted (Fig. 2) as functions of the quality of the radiation.The absolute intensity of radiation in quanta per square centimetre per second may be obtained from[Formula: see text]in which c is the ionization current per unit volume in the chamber, at standard temperature and pressure, produced by one quantum per square centimetre per second.The intensity of the radiation from one milligram of radium in equilibrium, and covered by platinum of wall thickness t, at one centimetre distance is (8.98 − 1.17 mm.−1 × t) roentgens per hour approximately, it t is not less than 0.3 mm.

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