The cross-section function for the
115
In(
γ
,
γ
′
)
115
m
In reaction was determined in the energy range up to E
γ
= 9.6 MeV using the bremsstrahlung facility at the MT25 Microtron, JINR, Dubna. ...Natural indium disks were irradiated with bremsstrahlung, each disk with a beam of different endpoint energy. To the measured saturation activity built up in the wide-energy photon beam we applied the unfolding technique, developed recently at the JRC-Geel with the primary purpose of being used in neutron activation. The results were compared with TALYS 1.9 calculations and existing experimental data. Our results suggest that the application of existing unfolding technique allow determining unknown excitation functions of photon-induced reactions.
Low background HPGe detector, shielded by lead, was used to collect background gamma spectra for more than 180 days. Three lines, originating from transitions of muons captured in orbitals of lead ...atoms were for the first time recognized in background spectra. Relative intensities of detected transitions were calculated and compared with the theoretical prediction.
Natural antimony targets were irradiated in a 60 MeV bremsstrahlung beam and gamma spectrometric measurements were performed. The goal was to establish the yield of 117mSn, a radionuclide with great ...potential for application in medicine. Considering that 117mSn is predominantly produced through a photonuclear reaction in which an charged particle is emitted (121Sb(γ,p3n)), the yield of this tin isotope is much lower than the yields of several antimony isotopes produced in (γ,xn) reactions. It has been estimated that photonuclear reactions on natural antimony could produce 117mSn activities needed for therapeutic applications, with accelerators having electron currents of the order of mA. For the used bremsstrahlung energy of 60 MeV, it was estimated how much 119mSn activity can be expected when exposing the antimony target.
•Natural Sb targets were exposed to 60 MeV bremsstrahlung.•Yield of 117mSn was determined using gamma spectroscopy.•It is estimated that (γ,xn) reaction can be used for production of 117mSn for medical purpose.
A new method for atmospheric correction of cosmic ray data is designed. It’s fully empirical, based on the principal component analysis. The method requires knowledge of the pressure and the ...temperature profile of the atmosphere. It’s applicable to all muon detectors. The method is tested on muon data from two detectors in Belgrade cosmic ray station, one located on the ground level and the other at the depth of 25 mwe. Correction reduces variance by 64.5% in ground level detector data and 38.1% in underground data. At the same time, the amplitude of the annual variation is reduced by 86.0% at ground level and 54.9% underground. With the same data sets the presented method performs better than the integral correction method.
Samples made from natural bismuth were exposed in 60 MeV end-point bremsstrahlung beam. In this paper, a simple model for determination the share of two ways of
203
Pb formation: by the decay of
203
...Bi, produced in
209
Bi(γ,6n)
203
Bi reaction and by
209
Bi(γ,p 5n)
203
Pb reaction is described. The method employs the ratio of
203
Pb and
203
Bi nuclei numbers and activities at the end of the exposure as the input value. This ratio was estimated from gamma spectra measured after irradiation of natural Bi sample. It was found that the rate of production of
203
Pb by
209
Bi(γ,p 5n)
203
Pb reaction is about 6% of the
203
Bi production rate in the
209
Bi(γ,6n)
203
Bi reaction. Obtained result is compared with TALYS based estimation.
The possibility of utilizing a shallow underground laboratory for the study of energy dependent solar modulation process is investigated. The laboratory is equipped with muon detectors at ground ...level and underground (25mwe), and with an underground asymmetric muon telescope to have a single site detection system sensitive to different median energies of primary cosmic-ray particles. The detector response functions to galactic cosmic rays are determined from Monte Carlo simulation of muon generation and propagation through the atmosphere and soil, based on CORSIKA and GEANT4 simulation packages. The present setup is suitable for studies of energy dependence of Forbush decreases and other transient or quasi-periodic cosmic-ray variations.
The most dominant source of indoor radon is the underlying soil, so the enhanced levels of radon are usually expected in mountain regions and geology units with high radium and uranium content in ...surface soils. Laboratory for radioactivity and dose measurement, Faculty of Sciences, University of Novi Sad has rich databases of natural radionuclides concentrations in Vojvodina soil and also of indoor radon concentrations for the region of Vojvodina, Northern Province of Serbia. In this paper we present the results of correlative and multivariate analysis of these results and soil characteristics in order to estimate the geogenic radon potential. The correlative and multivariate analysis were done using Toolkit for Multivariate Analysis software package TMVA package, within ROOT analysis framework, which uses several comparable multivariate methods for our analysis. The evaluation ranking results based on the best signal efficiency and purity, show that the Boosted Decision Trees (BDT) and Multi Layer Preceptor (MLP), based on Artificial Neural Network (ANN), are multivariate methods which give the best results in the analysis. The BDTG multivariate method shows that variables with the highest importance are radio-nuclides activity on 30 cm depth. Moreover, the multivariate regression methods give a good approximation of indoor radon activity using full set of input variables. On several locations in the city of Novi Sad the results of indoor radon concentrations, radon emanation from soil, gamma spectrometry measurements of underlying soil and geology characteristics of soil were analyzed in detail in order to verify previously obtained correlations for Vojvodina soil.
•Multivariate analysis of indoor radon and soil characteristics were performed.•The multivariate methods identify the most significant variables and radon priority areas.•Radionuclides in deep layers, humus and clay content have the most impact to indoor radon.
Correction of meteorological effects on muon component of secondary cosmic rays significantly extends the usability of muon monitors. We propose a new data driven empirical method for correction of ...meteorological effects on muon component of secondary cosmic rays, based on multivariate analysis. Several multivariate algorithms implemented in Toolkit for Multivariate Data Analysis with ROOT framework are trained and then applied to correct muon count rate for barometric and temperature effects. The effect of corrections on periodic and aperiodic cosmic ray variations is analyzed and compared with integral correction method, as well as with neutron monitor data. The best results are achieved by the application of linear discriminant method, which increases sensitivity of our muon detector to cosmic ray variations beyond other commonly used methods.
Plain Language Summary
Primary cosmic rays are energetic particles that arrive at Earth from space. On their journey toward Earth they are affected by the solar wind (a stream of charged particles emanating from the sun), which has information about various solar processes embedded in it. In top layers of the atmosphere primary cosmic rays interact with nuclei of air molecules and produce large number of secondary particles that propagate toward Earth's surface. These secondary particles preserve information about variations of primary cosmic rays, which allows for the study of solar processes using Earth based detectors. One type of secondary particles that can be detected on the ground are muons. However, muons are affected by the conditions in the atmosphere, which can disturb the information about variations of primary cosmic rays. That is why it is important to model these atmospheric effects on cosmic ray muons as well as possible so they can be corrected for. In this study, we present a new method for modeling and correction of atmospheric effects on cosmic ray muons, that is based on multivariate analysis utilizing machine learning algorithms. This method increases sensitivity of our muon detector to cosmic ray variations beyond other commonly used methods.
Key Points
Correction of meteorological effects on muon component of secondary cosmic rays significantly extends the usability of muon monitors
A new method for modeling of meteorological effects utilizing multivariate analysis and machine learning techniques is presented
Correction efficiency of the best performing algorithm is greater than for other commonly used methods
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