The article aims to study the possible correlation between the presence and intensity of rainfall X- and T-radiation and low energy neutrons at one specific location in S[io Jos6 dos Campos, SP, Brazil. Monitoring of ...The article aims to study the possible correlation between the presence and intensity of rainfall X- and T-radiation and low energy neutrons at one specific location in S[io Jos6 dos Campos, SP, Brazil. Monitoring of these parameters was carried out from end February to half of June 2013 just in Physics Department of ITA （Technological Institute of Aeronautics）. By correlating the data of measurements of intensity of X and ）,-radiations with the rainfall it has been found that this meteorological parameter had a significant influence on the background of these radiation profile. A possible reason for this fact is associated with the presence of radon gas in the environment that is dragged to the surface during the occurrences of local rainfall. In relation neutrons, it was possible to note that the rainfall has small influence on this parameter measures.展开更多
A large volume spherical ionization chamber of 195 mm diameter and 0.36 mg/cm2wall thickness made from conducting carbon-fibre epoxy composite material has been developed. The mechanical intensity of the chamber is sa...A large volume spherical ionization chamber of 195 mm diameter and 0.36 mg/cm2wall thickness made from conducting carbon-fibre epoxy composite material has been developed. The mechanical intensity of the chamber is satisfactory for a good longterm volume stability. Owing to its large volume and thin wall, the chamber is sensitive to low energy photon beams and has excellent energy-response characteristics. This ionization chamber is suitable not only for a laboratory reference but also for measurement of low energy photon beam exposure rates at protection-level.展开更多
Low energy gamma radiation （0.2-10.0） MeV near the Earth＇s surface has several origins. Primary and secondary cosmic radiations with interactions of very high energy protons （〉 1 GeV） in terrestrial atmosphere a...Low energy gamma radiation （0.2-10.0） MeV near the Earth＇s surface has several origins. Primary and secondary cosmic radiations with interactions of very high energy protons （〉 1 GeV） in terrestrial atmosphere are the main sources. The second most important source near the surface of the Earth and in the tropical and equatorial regions is the radon gas （Rn-222） that decays in alpha particles and gamma rays in this energy range. Also the telluric radionuclides 238U, 235U, 40K and 232Th in decays produce gamma radiation with different intensities at different locations on the surface of the Earth. Other sources less present are electrical discharges （lightning strikes） and man-made radioactive sources for medical, dental and industrial applications. In this work, it is shown that measurements of these components during all year 2016 are carried out at the ITA （Technological Institute of Aeronautics） campus in Sao Jose dos Campos, SP, Brazil and their possible correlations with atmospheric phenomena.展开更多
The singlet rigid Be--O dissociation potential energy curves correlating to the first four molecular limits of （BeH2O）^2＋ com- plex were calculated using the multi-reference single and double excitation configurati...The singlet rigid Be--O dissociation potential energy curves correlating to the first four molecular limits of （BeH2O）^2＋ com- plex were calculated using the multi-reference single and double excitation configuration interaction theory. The radial cou- plings of three low-lying IAl states were calculated and combined with adiabatic potential energy curves to investigate and charge- transfer collision dynamics by using quantum-mechanical molecular orbital close-coupling methods. It is found that the total charge-transfer cross sections are dominated by the Be^＋（^2S）＋H2O＋（A^2A1） channel. The rate coefficients in the range of 10^-17 - 10^-12 cm^3/s are very sensitive to temperature below 1000 K. The complexation energy without charge-transfer was determined to be 143.6 kcal/mol, including zero-point vibration energy corrections. This is in good agreement with the previous results.展开更多
Cosmic rays(CR)play an important role in space weather-related studies.Their temporal variability,both of a quasi-periodic character as well as an irregular one,has been studied from ground-based direct measurements,a...Cosmic rays(CR)play an important role in space weather-related studies.Their temporal variability,both of a quasi-periodic character as well as an irregular one,has been studied from ground-based direct measurements,as well as from cosmogenic nuclides,over a long time.We attempt to describe the current knowledge of selected quasi-periodicities in CR flux in the energy range above the atmospheric threshold,from direct measurements.The power spectrum density(PSD)of the CR time series as measured by neutron monitors(NMs)and by muon detectors has a rather complicated character.Along with the shape(slope)of the PSD,knowledge of the contribution of quasi-periodic variations(q-per)to the CR signal is of importance for the modulation,as well as for checking the links of CR to space weather,and/or to space climate effects.The rotation of the Earth and solar rotation cause two types of mechanisms behind the certain q-per observed in secondary CR on the Earth’s surface.Solar activity and solar magnetic field cyclicities contribute to the q-per signals in CR if studied over a longer time.The complexity of the spatial structure of the interplanetary magnetic field(IMF)and its evolution within the heliosphere,in addition to the changes in the geomagnetic field,cause variability in contributions of the q-per in CR.Wavelet spectra are useful tools for checking the fine structure of q-per and their temporal behaviour.Over a long time NMs and muon telescopes provide information about q-per in CR.展开更多
文摘The article aims to study the possible correlation between the presence and intensity of rainfall X- and T-radiation and low energy neutrons at one specific location in S[io Jos6 dos Campos, SP, Brazil. Monitoring of these parameters was carried out from end February to half of June 2013 just in Physics Department of ITA （Technological Institute of Aeronautics）. By correlating the data of measurements of intensity of X and ）,-radiations with the rainfall it has been found that this meteorological parameter had a significant influence on the background of these radiation profile. A possible reason for this fact is associated with the presence of radon gas in the environment that is dragged to the surface during the occurrences of local rainfall. In relation neutrons, it was possible to note that the rainfall has small influence on this parameter measures.
文摘A large volume spherical ionization chamber of 195 mm diameter and 0.36 mg/cm2wall thickness made from conducting carbon-fibre epoxy composite material has been developed. The mechanical intensity of the chamber is satisfactory for a good longterm volume stability. Owing to its large volume and thin wall, the chamber is sensitive to low energy photon beams and has excellent energy-response characteristics. This ionization chamber is suitable not only for a laboratory reference but also for measurement of low energy photon beam exposure rates at protection-level.
文摘Low energy gamma radiation （0.2-10.0） MeV near the Earth＇s surface has several origins. Primary and secondary cosmic radiations with interactions of very high energy protons （〉 1 GeV） in terrestrial atmosphere are the main sources. The second most important source near the surface of the Earth and in the tropical and equatorial regions is the radon gas （Rn-222） that decays in alpha particles and gamma rays in this energy range. Also the telluric radionuclides 238U, 235U, 40K and 232Th in decays produce gamma radiation with different intensities at different locations on the surface of the Earth. Other sources less present are electrical discharges （lightning strikes） and man-made radioactive sources for medical, dental and industrial applications. In this work, it is shown that measurements of these components during all year 2016 are carried out at the ITA （Technological Institute of Aeronautics） campus in Sao Jose dos Campos, SP, Brazil and their possible correlations with atmospheric phenomena.
文摘The singlet rigid Be--O dissociation potential energy curves correlating to the first four molecular limits of （BeH2O）^2＋ com- plex were calculated using the multi-reference single and double excitation configuration interaction theory. The radial cou- plings of three low-lying IAl states were calculated and combined with adiabatic potential energy curves to investigate and charge- transfer collision dynamics by using quantum-mechanical molecular orbital close-coupling methods. It is found that the total charge-transfer cross sections are dominated by the Be^＋（^2S）＋H2O＋（A^2A1） channel. The rate coefficients in the range of 10^-17 - 10^-12 cm^3/s are very sensitive to temperature below 1000 K. The complexation energy without charge-transfer was determined to be 143.6 kcal/mol, including zero-point vibration energy corrections. This is in good agreement with the previous results.
基金Project VEGA 2/0040/13 for supportKuwait for supporting project HS-13-01
文摘Cosmic rays(CR)play an important role in space weather-related studies.Their temporal variability,both of a quasi-periodic character as well as an irregular one,has been studied from ground-based direct measurements,as well as from cosmogenic nuclides,over a long time.We attempt to describe the current knowledge of selected quasi-periodicities in CR flux in the energy range above the atmospheric threshold,from direct measurements.The power spectrum density(PSD)of the CR time series as measured by neutron monitors(NMs)and by muon detectors has a rather complicated character.Along with the shape(slope)of the PSD,knowledge of the contribution of quasi-periodic variations(q-per)to the CR signal is of importance for the modulation,as well as for checking the links of CR to space weather,and/or to space climate effects.The rotation of the Earth and solar rotation cause two types of mechanisms behind the certain q-per observed in secondary CR on the Earth’s surface.Solar activity and solar magnetic field cyclicities contribute to the q-per signals in CR if studied over a longer time.The complexity of the spatial structure of the interplanetary magnetic field(IMF)and its evolution within the heliosphere,in addition to the changes in the geomagnetic field,cause variability in contributions of the q-per in CR.Wavelet spectra are useful tools for checking the fine structure of q-per and their temporal behaviour.Over a long time NMs and muon telescopes provide information about q-per in CR.
