Energy Gamma Radiation Research Articles

Gamma radiation and magnetic field mediated delay in effect of accelerated ageing of soybean.

Soybean seeds were exposed to gamma radiation (0.5, 1, 3 and 5kGy), static magnetic field (50, 100 and 200 mT) and a combination of gamma radiation and magnetic energy (0.5kGy + 200 mT and 5kGy + 50 mT) and stored at room temperature for six months. These seeds were later subjected to accelerated ageing treatment at 42°C temperature and 95-100% relative humidity and were compared for various physical and biochemical characteristics between the untreated and the energized treatments. Energy treatment protected the quality of stored seeds in terms of its protein and oil content . Accelerated aging conditions, however, affected the oil and protein quantity and quality of seed negatively. Antioxidant enzymes exhibited a decline in their activity during aging while the LOX activity, which reflects the rate of lipid peroxidation, in general, increased during the aging. Gamma irradiated (3 and 5kGy) and magnetic field treated seeds (100 and 200 mT) maintained a higher catalase and ascorbate peroxidase activity which may help in efficient scavenging of deleterious free radical produced during the aging. Aging caused peroxidative changes to lipids, which could be contributed to the loss of oil quality. Among the electromagnetic energy treatments, a dose of 1-5kGy of gamma and 100 mT, 200mT magnetic field effectively slowed the rate of biochemical degradation and loss of cellular integrity in seeds stored under conditions of accelerated aging and thus, protected the deterioration of seed quality. Energy combination treatments did not yield any additional protection advantage.

CEPA: A LaBr3(Ce)/LaCl3(Ce) PHOSWICH ARRAY FOR SIMULTANEOUS DETECTION OF PROTONS AND GAMMA RADIATION EMITTED IN REACTIONS AT RELATIVISTIC ENERGIES

A sophisticated design of 750 LaBr3(Ce):LaCl3(Ce) phoswich crystals (CEPA10) with a segmentation determined by the Doppler correction and an energy resolution of 5% at 1 MeV is presented. Monte Carlo simulations have been performed for high energy protons (50–500 MeV) and gamma radiation (0.5–30 MeV) to determine the length and shape of the crystals for optimum performance of the detector. In the case of protons, the two-layer detector can be used as a ΔELaBr3 − ETot telescope or, for very high energies, as a double energy loss detector (ΔELaBr3 + ΔELaCl3), in order to determine the initial energy. In addition, an experimental test with high energy protons (70–230 MeV) was performed at the cyclotron center in Krakow, Poland with a first prototype of 2 x 2 phoswich rectangular crystals (CEPA4) packed in an aluminum can (0.5 mm case). To simulate CEPA10 efficiencies and resolutions, optical pulses detected in CEPA4 by photomultiplier tubes with a DAQ system were used as energy input functions in Monte Carlo simulations.

Attenuation coefficients and absorbed gamma radiation energy of different varieties of potato, mango and prawn at different storage time and physiological condition

Attenuation coefficients of different varieties of gamma irradiated potato (Kufri Chandramukhi, Kufri Jyoti, and Kufri Sindhuri), mango (Himsagar, Langra, Dashehri and Fazli) and prawn (Tiger prawn and Fresh water prawn) of different storage time and physiological stages were determined. After six months storage attenuation coefficient of Kufri Chandramukhi was decreased by 30.8% with decrease of density and moisture content. Decreasing trend of attenuation coefficient during storage was more prominent (almost 50%) in other two varieties of potato. On the other hand in all four varieties, unripe mango consisted of significantly less (p⩽0.05) attenuation coefficient (around 11–14%) than the ripe one due to changes in physiological properties and density. Different varieties of prawn had different attenuation coefficients due to subtle differences in their proximate composition. Due to having different attenuation coefficients, different food components, even different varieties of same food component absorbed different gamma radiation energy though exposed to same radiation dose.

Long-term observations of the Seyfert galaxy NGC 1275 at ultrahigh energies by SHALON mirror Cherenkov telescopes

The Seyfert galaxy NGC 1275 is a central dominant galaxy in the Perseus cluster of galaxies. NGC 1275 is known as a powerful source of radio and X-ray radiations. In 1996, in SHALON telescope observations, a new metagalactic source of gamma radiation of ultrahigh energy > 800 GeV was detected. The position of the radiation source detected in our experiment is consistent in its coordinates with the Seyfert Galaxy NGC 1275. The results obtained at high and ultrahigh energies are necessary to understand the radiation generation processes in the entire wide energy range.

Radionuclide production

AbstractThis article continues from the earlier article “An Introduction to Nuclear Medicine” where the general principles of nuclear medicine were discussed. Radionuclides are required in both diagnostic and therapeutic nuclear medicine procedures. Naturally occurring radionuclides are generally not suitable for diagnostic and therapeutic procedures due to their typically long half‐lives or less than ideal physical or chemical characteristics; therefore appropriate radionuclides need to be produced. The common methods of radionuclide production for nuclear medicine include: fission, neutron activation, cyclotron and generator.Fission occurs in a nuclear reactor where neutrons are used to bombard fission nuclides such as uranium‐235 (235U) or plutonium‐239 (239Pu). Fission results in the splitting of the large nucleus into smaller fission fragments along with the release of gamma radiation and high energy neutrons. Neutron activation also takes place in a nuclear reactor. The neutrons are used to bombard stable nuclides to form other radionuclides. There are disadvantages with this process so other production means are often preferred.Cyclotrons are used to accelerate charged particles such as protons (p), deuterons (d), triton (t) and alpha (α) particles to high velocities to penetrate the orbital electrons of the target atom and interact with the nucleus. Generators produce the most commonly used radionuclide in nuclear medicine, technetium‐99m (99mTc). The radionuclide generator sees the decay of a long half‐life parent radionuclide to a short half‐life daughter radionuclide. The daughter is the radionuclide used in nuclear medicine.An understanding of radionuclide production will assist in the understanding of both diagnostic and therapeutic nuclear medicine procedures.

Analysis of classifier variability between sessions and subjects for constructing brain machine interface using multiple subject's data

Attenuation coefficients of different varieties of gamma irradiated potato (Kufri Chandramukhi, Kufri Jyoti, and Kufri Sindhuri), mango (Himsagar, Langra, Dashehri and Fazli) and prawn (Tiger prawn and Fresh water prawn) of different storage time and physiological stages were determined. After six months storage attenuation coefficient of Kufri Chandramukhi was decreased by 30.8% with decrease of density and moisture content. Decreasing trend of attenuation coefficient during storage was more prominent (almost 50%) in other two varieties of potato. On the other hand in all four varieties, unripe mango consisted of significantly less (p ⩽ 0.05) attenuation coefficient (around 11–14%) than the ripe one due to changes in physiological properties and density. Different varieties of prawn had different attenuation coefficients due to subtle differences in their proximate composition. Due to having different attenuation coefficients, different food components, even different varieties of same food component absorbed different gamma radiation energy though exposed to same radiation dose.

Spectral peculiarities of high energy X-ray radiation, gamma radiation, and Submillimeter radio emission in the impulsive phase of a solar flare

We analyze experimental data on the temporal behavior of fluxes and energy spectra of hard solar X-ray and gamma radiation in the energy range of 0.015 to 300 MeV, obtained onboard the CORONAS-F satellite during a solar flare on August 25, 2001. These data are compared with measurements of the radio emission fluxes over the wide frequency range of 1–405 GHz. For our analysis, we use data obtained onboard the YOHKOH, TRACE and GOES satellites, along with ground-based observations of this solar event using the Solar Submillimeter Telescope (SST; Argentina). For the first time, we find nearly simultaneous changes in the energy spectra of gamma radiation over the range 10–150 MeV and the frequency spectrum of radio emission at the beginning and during a impulsive phase of this event (whose duration did not exceed three minutes).

A note on irradiated heparin: some biological and chemical properties.

Abstract The effect of gamma radiation and high energy electrons on the anticoagulant and antilipaemic properties of heparin has been investigated. There was a fall in both activities, but the anticoagulant was reduced more readily than the antilipaemic. After electron bombardment the anticoagulant activities of two different batches of heparin were reduced almost identically, an unexpected finding since such a high degree of reproducibility is not possible with chemical degradation.

The NATALYA-2M spectrometer of high-energy radiations for the CORONAS-PHOTON space project

The NATALYA-2M high-energy radiation spectrometer is an element of the complex of scientific equipment of the CORONAS-PHOTON satellite. The instrument intended for registering gamma radiation of solar flares in the broad energy range of 0.2–1600 MeV as well as neutrons of solar origin with energies of 20–300 MeV represents itself as a scintillation spectrometer based on CsI(Tl) crystals with a total area of 32 × 38 cm2 and the thickness of 18 cm. The spectra and time profiles of the gamma quanta count rates are measured in four subranges: R (0.2–2 MeV), L (1–18 MeV), M (7–250 MeV), and H (50–1600 MeV). Depending on the gamma radiation energy, the effective area of the instrument varies within the range from 750 to 900 cm2, and the energy resolution at the Cs-137 line (662 keV) is 10%, it being about 30% at energies higher than 50 MeV. A system of stabilization based on the signal from the generator of reference light pulses is used to provide stability and automated adjustment of the parameters of spectrometric modules. The measuring channels of the instrument are calibrated during the flight using a source of “tagged” gamma quanta on the Co-60 radioactive isotope. Polystyrene scintillation counters are used to provide protection from the background of charged particles. The “CORONAS-PHOTON” spacecraft (SC) was launched from the Plesetsk spaceport on January 30, 2009, to a low circular near-Earth orbit (the altitude is 550 km, the inclination is 82.5°). On February 27, the first scientific data were obtained from the NATALYA-2M instrument. The results of the flight calibration of the instrument detectors in different energy channels demonstrated good agreement with the ground measurements. The paper describes the instrument and observational potentials of the NATALYA-2M spectrometer, gives the results of the adjustment and calibration, and exemplifies the registration of gamma-ray bursts (GRBs)on the orbit.

Gamma spectrometric measurements of depth-related radionuclide distribution in walls

The method for depth-related radionuclide distribution was evolved for approximate determination of the spatial lay-out of radionuclides in materials. The method is based on different attenuation coefficients for various energies of gamma radiation. For each material, the attenuation coefficient decreases with rising energy of radiation. It is therefore possible to assess the location of radionuclides in a material owing to attenuation on the track which a photon has to pass through the material. In this case, gamma lines with energies 609 and 1764 keV produced by nuclide (214)Bi were used for depth-related radionuclide distribution. This application should be suitable for locating radionuclides in the walls of buildings where high dose rates from gamma radiation occur. These doses are caused by natural radionuclides, mainly radium daughters. The presence of radionuclides in houses poses a high risk associated with inhalation of radon and its decay products. For suitable remediation, it is necessary to know the radionuclide depth distribution.

A validity test of E = m ⋅ c 2

The comparison of mass and energy variation in a nuclear reaction allows an experimental verification of Einstein’s energy - mass equivalence principle. Mass measurements are performed in a high precision Penning trap and yield values in unified atomic mass units. The energies of emitted gamma radiation are determined via Laue-diffraction with perfect crystals. The according values of the gamma ray wave lengths are expressed in units of the crystal lattice constant. The comparison of masses and wave lengths requires a conversion factor, which represents the unified atomic mass unit within the SI unit system. The latter is given by the molar Planck constant N A h, which itself is known via its relation to the fine structure constant. In the present paper we report on measurements carried out until 2003 with an uncertainty level of 4 ⋅ 10-7. We discuss the main limitations of these experiments and outline the possibilities for future measurements at the 10-8 level. Such measurements would allow a direct representation of the unified atomic mass unit in terms of a Compton frequency and are of utmost importance for a future re-definition of the kilogram mass unit.

Interaction of fast electrons and gamma-quanta with radiation protection ferric oxide composites

Physical processes of fast electron and gamma-radiation beam interaction with radiation protection ferric oxide composite materials are investigated together with dependences of energy (flux) accumulation and transmission coefficients on the gamma-radiation energy and thickness of a protective screen. Integral characteristics of radiation protection materials are calculated.

Quantitative accuracy analysis of burnup calculations for BNPP fuel assemblies using FFTBM method

A Fast Fourier Transform Based Method (FFTBM) analysis is carried out to determine the accuracy and validation of burnup calculations for Bushehr Nuclear Power Plant (BNPP), with two different codes. WIMSD5 and ORIGEN-2 are used for burnup calculations. Two types of fuel assembly configurations are modeled in evaluating 14 fission products' (FPs) concentrations during 2 and 3 year fuel cycles. The fission products are selected based on their radiological importance in shielding, the energy of gamma radiation, half life, availability of isotope from WIMS and ORIGEN results and their importance in criticality calculations. Despite different approach of burnup calculations by the two codes, FFTBM quantitative analysis showed very good agreement between the results.

Determination of atom displacement distribution in YBCO superconductors induced by gamma radiation

AbstractThe calculation results of the atom displacement distribution induced by gamma radiation in the superconducting material YBa2Cu3O7–x are presented. Firstly, a direct calculation procedure for the atom displacement distribution inside a given material is introduced, starting from the application of the energy flux distribution values of secondary electrons, formerly calculated using the Monte Carlo method based code system MCNP‐4C. Finally, calculation results of the atom displacement distribution, regarding the occupied oxygen crystalline sites, are presented for different incident gamma radiation energies, where an atom displacement threshold energy value of 20 eV was assigned to O(1–3) sites, while a value of 3.45 eV was used for the copper–oxygen chain sites at the basal plane. According to the present calculations, a predominating atom displacement rate at copper‐oxygen chain sites was obtained. On the other hand, nearly linear correlations among atom displacements and energy deposition profiles were also found. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

On the origin of highest energy gamma-rays from Mkn 501

The spectra of very high energy gamma-radiation from distant extragalactic objects suffer significant deformations during the passage of primary gamma-rays through the intergalactic medium. The recently reported fluxes of diffuse infrared background radiation indicate that we detect, most probably, heavily absorbed TeV radiation from Mkn 421 and Mkn 501. This implies that the absorption-corrected spectrum of Mkn 501 may contain a sharp pile-up which contradicts to the predictions of the conventional models of TeV blazars, and thus may leads to the so-called IR background-TeV gamma-ray crisis. To overcome this difficulty, in this paper we propose two independent hypotheses assuming that (i) the TeV radiation from Mkn 501 has a secondary origin, i.e. it is formed during the development of electron-photon cascades in the intergalactic medium initiated by primary gamma-rays; (ii) the pile-up in the source spectrum is a result of (in deep Klein-Nishina regime) of ambient optical radiation by an ultrarelativistic conical cold outflow (jet) with motion Lorentz factor Gamma_0 >= 3 10^7. Within the uncertainties caused by the limited energy resolution of spectral measurements, the observed TeV radiation of Mkn 501 formally can be explained by the intergalactic cascade gamma-rays, assuming however an extremely low intergalactic magnetic field in the direction to the source at the level of < 10^{-18} G. We also demonstrate that the bulk motion comptonization scenario can quite naturally reproduce the unusual spectral features in the absorption-corrected TeV spectrum of Mkn 501, and briefly discuss the astrophysical implications of this hypothesis.

Effect of gamma irradiation on the piezoelectric properties of K2Sr4Nb10O30-K6Li4Nb10O30 solid solutions

The effect of gamma irradiation on the dielectric (e Τ 33 /e0, tanδ) and piezoelectric (d 31 , g 31 , K p , Q m ) properties of К2Sr4Nb10O30–K6Li4Nb10O30 solid solutions (tetragonal tungsten bronze structure) was studied as a function of K6Li4Nb10O30 content. The results demonstrate that increasing the gamma dose to 9 × 105 Gy reduces e Τ 33 /e0 and tanδ. With increasing Li+ content (filling of triangular channels), d 31, g 31, K p, and Q m increase. The results are interpreted in terms of the generation of stable defects and effective redistribution of the energy of gamma radiation over the ceramic sample.

The effect of heterogeneity in gamma-ray albedo analysis of mineral raw materials

The influence of heterogeneity on the results of a gamma-ray albedo analysis of heterogeneous raw materials has been considered. The heterogeneity error components, caused by dispersing the defined element in the bulk under study and by the direct influence of the particles dimension (grain size) on the intensity of the scattered gamma-rays, have been determined. Mathematical models to describe the dependence of the error on the chemical composition of the raw material under study, the component densities, the particles dimensions and the primary gamma-radiation energy have been suggested.

Wide aperture delta-loop anode proportional counter

Abstract An end-window gas proportional detector with a triangular loop anode is designed to count X-ray and gamma radiation of energy 6–40 keV mainly for the nuclear gamma-resonance spectroscopy. It offers as good energy resolution (FWHM 10–12% at 14.4 keV; ≅17% at 6.4 keV) and spectral purity (peak/background ≈20−30) as coaxial proportional counters, and window area (diameter 50–60 mm) as large as usual NGRS scintillation detectors. The detector will allow the use of lower activity gamma sources and improve the speed and accuracy of the measurements.

Limits on the Isotropic Diffuse Flux of Ultrahigh EnergyγRadiation

Diffuse ultrahigh energy gamma-radiation can arise from a variety of astrophysical sources, including the interaction of extremely high energy cosmic rays with the 3K microwave background radiation or the collapse of topological defects created in the early Universe. We describe a sensitive search for diffuse gamma-rays at ultrahigh energies using the CASA-MIA experiment. An isotropic flux of radiation is not detected, and we place stringent upper limits on the fraction of the gamma-ray component relative to cosmic rays (less than one part in 10,000) at energies from 570 TeV to 55,000 TeV. This result represents the first comprehensive constraint on the gamma-ray flux at these energies.

Measurement of the peripheral dose for the tangential breast treatment technique with Co-60 gamma radiation and high energy X-rays

Background and purpose: Published data to estimate the dose outside the primary beam, i.e. the peripheral dose (PD), are only valid for perpendicularly incident beams. In radiotherapy of breast cancer patients often a tangential beam technique is used, for which the published PD data cannot be applied. Material and methods: Measurements were made in a water phantom for three sizes of a breast phantom, representing a small, medium, and large breast. Open and wedged beams were used. Photon energies were 60Co gamma radiation and 6- to 25-MV X-rays. The PD was also determined in a humanoid phantom. To check the validity of the phantom measurements, the PD was measured in 50 patients referred to this institute for radiotherapy of the breast. Results: The mean of the ratios of the measured to the estimated PD was 1.12, with a standard deviation of 26%. The data set was used to estimate the fetal dose for a ‘standard’ patient, as a function of stage of pregnancy. Conclusions: The measurements have resulted in a data set, which enables calculation of the peripheral dose for the tangential beam technique. The accuracy is considered to be adequate for risk assessment.