Measurements Of Background Radiation Research Articles

Improved model of large-field inflation with primordial black hole production in Starobinsky-like supergravity

Abstract A viable model of large-field (chaotic) inflation with efficient production of primordial black holes is proposed in Starobinsky-like (modified) supergravity leading to the ‘no-scale-type’ Kähler potential and the Wess-Zumino-type (‘renormalizable’) superpotential. The cosmological tilts are in good (within 1σ) agreement with Planck measurements of the cosmic microwave background radiation. In addition, the power spectrum of scalar perturbations has a large peak at smaller scales, which leads to a production of primordial black holes from gravitational collapse of large perturbations with the masses about 1017 g. The masses are beyond the Hawking (black hole) evaporation limit of 1015 g, so that those primordial black holes may be viewed as viable candidates for a significant part or the whole of the current dark matter. The parameters of the superpotential were fine-tuned for those purposes, while the cubic term in the superpotential is essential whereas the quadratic term should vanish. The vacuum after inflation (relevant to reheating) is Minkowskian. The energy density fraction of the gravitational waves induced by the production of primordial black holes and their frequency were also calculated in the second order with respect to perturbations.

Measurement of background radiations and spectra of X-ray sources using low-cost stratospheric balloon missions

In small balloon missions, some in situ radiation is added to the targeted strong persistent astronomical sources (such as, the Sun, Crab, Cygnus X-1, etc.) or transient sources, such as solar flares, gamma-ray bursts, etc., during their detection, i.e., the background radiation. For measurement and modeling of background radiation, we use the data of the low-cost, small, stratospheric, high-altitude balloon-borne missions conducted by Indian Centre for Space Physics. In this paper, we show several models to estimate the background counts where the strong X-ray sources are detected at the altitude range of ∼35–42 km even in the absence of onboard pointing system and severe atmospheric absorption. For all data analysis purposes, the photons detected in the detector are in the energy range of 10–80 keV. Moreover, we found that the observed data is within ±1σ of the calculated background model. Finally, using these background models, we estimate the spectra and luminosity of the Crab nebula and the black hole candidate Cygnus X-1, which agree with the previously published results.

Dilaton–Axion modular inflation in supergravity

Dilaton and axion are ubiquitous in extended supergravities and closed superstrings. We propose new models of modular inflation in four-dimensional [Formula: see text] supergravity coupled to the chiral dilaton–axion–goldstino supermultiplet, which fit some necessary conditions of superstring cosmology. The model parameters are tuned to obey precision measurements of the cosmic microwave background radiation. We employ the modular-invariant superpotentials and asymptotically modular-invariant Kähler potentials, and achieve axion stabilization with high-scale supersymmetry breaking.

Measurement of background radiation in Jhapa, Ilam, Panchthar, and Taplejung districts of Nepal

In this study, we investigated the levels of background radiation in different locations across the Eastern part of Koshi province, specifically in Taplejung, Panchthar, Ilam, and Jhapa. We used a portable Geiger Muller counter to collect data from twenty different locations, with five sites taken from each district. The average absorbed dose rate was found to be 0.243±0.035 mSv/y. The highest measured value of absorbed dose was 0.335±0.041 mSv/y at Pathivara temple in Taplejung, and the lowest was found to be 0.197±0.039 mSv/y at Kakarvita, Jhapa. The results suggest that these four districts do not pose any radiation risk because it was below the threshold of risk (1mSv/y). We also measured the variation of absorption dose with altitude which is positively correlated with altitude with a correlation coefficient of +0.57. This might be because of the surge in cosmic radiation with an increase in altitude.

Production of Primordial Black Holes in Improved E-Models of Inflation

E-type α-attractor models of single-field inflation were generalized further in order to accommodate production of primordial black holes (PBHs) via adding a near-inflection point to the inflaton scalar potential at smaller scales, in good agreement with measurements of cosmic microwave background (CMB) radiation. A minimal number of new parameters were used but their fine-tuning was maximized in order to increase the possible masses of PBHs formed during an ultra-slow-roll phase, leading to a large enhancement in the power spectrum of scalar (curvature) perturbations by 6 or 7 orders of magnitude against the power spectrum of perturbations observed in CMB. It was found that extreme fine-tuning of the parameters in our models can lead to the formation of moon-sized PBHs, with masses of up to 1026 g, still in agreement with CMB observations. Quantum corrections are known to lead to the perturbative upper bound on the amplitude of large scalar perturbations responsible for PBH production. The quantum (one-loop) corrections in our models were found to be suppressed by one order of magnitude for PBHs with masses of approximately 1019 g, which may form the whole dark matter in the Universe.

Dark matter and neutrino masses in a Portalino-like model

We explore a Portalino-like model of dark matter and neutrino masses in which right-handed neutrino fields connect gauge neutral operators from the Standard Model and Hidden Sector. Neutrino masses are generated via a seesaw-like mechanism that can explain the light active neutrino masses. The model includes a “Portalino” state that connects the two sectors via the neutrino portal. Dark Matter in this model consists of a hidden sector Dirac fermion that dominantly freezes-out via resonant annihilations into other hidden sector states, which ultimately results in a population of Portalinos. Due to small mixing in the extended neutrino sector these Portalinos tend to be cosmologically long lived, decaying into Standard Model particles leading to constraints on the model from Big Bang Nucleosynthesis and measurements of the Cosmic Microwave Background radiation. Combining these limits with direct constraints on the size of the Portalino–neutrino mixing and the assumptions of the model the viable mass ranges for the Portalino states are found to be {0.02}~hbox {eV}lesssim m_n lesssim {6.4}~hbox {eV} or {489}~{hbox {MeV}} lesssim m_n lesssim TeV. Indirect dark matter signals in the form of highly boosted, mono-energetic Portalinos produced in Dark Matter annihilations provide a target for neutrino telescopes.

Post-Inflationary Production of Dark Matter after Inflection Point Slow Roll Inflation

We explore a feasible model that combines near-inflection point small-field slow roll inflationary scenario driven by single scalar inflaton with the production of non-thermal vector-like fermionic dark matter, χ, during the reheating era. For the inflationary scenario, we consider two separate polynomial forms of the potential; one is symmetric about the origin, and the other is not. We fix the coefficients of the potentials satisfying current Planck-Bicep data. We calculate the permissible range of yχ and mχ for the production of enough dark matter to explain the total Cold Dark Matter (CDM) mass density of the present universe while satisfying Cosmic Background Radiation (CMBR) measurements and other cosmological bounds.

On the superstring-inspired quantum correction to the Starobinsky model of inflation

Superstring/M-theory is the theory of quantum gravity that can provide the UV-completion to viable inflation models. We modify the Starobinsky inflation model by adding the Bel-Robinson tensor Tμνλρ squared term proposed as the leading quantum correction inspired by superstring theory. The (R + 1/6m 2 R 2 - β/8m 6 T 2) model under consideration has two parameters: the inflaton mass m and the string-inspired positive parameter β. We derive the equations of motion in the Friedmann-Lemaitre-Robertson-Walker universe and investigate its solutions. We find the physical bounds on the value of the parameter β by demanding the absence of ghosts and consistency of the derived inflationary observables with the measurements of the cosmic microwave background radiation.

Gamma-ray bursts, supernovae Ia, and baryon acoustic oscillations: A binned cosmological analysis

Abstract Cosmological probes at any redshift are necessary to reconstruct consistently the cosmic history. Studying properly the tension on the Hubble constant, H0, obtained by supernovae type Ia (SNe Ia) and the Planck measurements of the cosmic microwave background radiation would require complete samples of distance indicators at any epoch. Gamma-ray bursts (GRBs) are necessary for the aforementioned task because of their huge luminosity that allows us to extend the cosmic ladder to very high redshifts. However, using GRBs alone as standard candles is challenging, because their luminosity varies widely. To this end, we choose a reliable correlation for GRBs with a very small intrinsic scatter: the so-called fundamental plane correlation for GRB afterglows corrected for selection biases and redshift evolution. We choose a well defined sample: the platinum sample, composed of 50 long GRBs. To further constrain the cosmological parameters, we use baryon acoustic oscillations (BAOs) given their reliability as standard rulers. Thus, we have applied GRBs, SNe Ia, and BAOs in a binned analysis in redshifts so that the GRB contribution is fully included in the last redshift bin, which reaches z = 5. We use the fundamental plane correlation (also known as the 3D Dainotti relation), together with SNe Ia and BAOs, to constrain H0 and the density matter today, ΩM. This methodology allows us to assess the role of GRBs combined with SNe Ia and BAOs. We have obtained results for H0 and ΩM using GRBs+SNe Ia+BAOs with better precision than SNe Ia alone for every bin, thus confirming the beneficial role of BAOs and GRBs added together. In addition, consistent results between GRBs+SNe Ia+BAOs are obtained when compared with SNe Ia+BAOs, showing the importance of GRBs since the distance ladder is extended up to z = 5 with a similar precision obtained with other probes without including GRBs.

Observational constraints on interacting dark energy models with multiple measurements of quasars

Dark energy and dark matter, two subjects of basic physics, have received a lot of attention in the 21st century. From the observational point of view, the interaction between dark energy and dark matter can significantly affect cosmological distances. This gives rise to the possibility of indirectly detecting such interaction through high-redshift cosmological probes. Theoretically, the introduction of interaction between dark energy and dark matter can assist in alleviating the coincidence problem of the standard cosmological model ($\Lambda$CDM model). Furthermore, this can provide a new method of studying the properties of dark matter particles. In this paper, based on the latest observations of multiple measurements of quasars (X-ray+UV quasars acting as standard candles, compact radio quasars acting as standard rulers) covering the redshift range of $0.04~<~z~<~5.1$ and baryonic acoustic oscillation between ($0.38~<~z~<~2.34$), we investigate the observational constraints on a variety of interacting dark energy models ($\gamma_d~$IDE model, $\gamma_m~$IDE model) and other cosmological models ($\Lambda$CDM model, XCDM model). The results provide us with a quantitative analysis of the possible interaction between dark energy and dark matter, as well as the possible range of the mass of dark matter particles. The joint analysis shows that: (1) Multiple measurements of quasars can provide more stringent constraints on the interacting dark energy models, which can further strengthen the potential of quasars acting as effective cosmological standard probes at higher redshifts; (2) In the framework of both $\gamma_m$IDE model and $\gamma_d$IDE model, the quasar data supports possible conversion of dark energy into dark matter at high redshift, which alleviates the coincidence problem to some extent. We also found that the interaction term is of a small value, which demonstrates the negligible interaction between dark matter and dark energy; (3) In the framework of $\Lambda$CDM model, which has shown the best consistency with quasar data, the density parameter of matter in the Universe is constrained at $\Omega_~m=0.317^{+0.007}_{-0.007}$, with the best-fit Hubble constant $H_0=68.177^{+0.497}_{-0.505}$ at 68.3% confidence level. These findings are consistent with the recent microwave background radiation (CMB) measurements from the Planck satellite; (4) If dark matter in the Universe exists in the form of scalar-field dark matter with $Z_2$ symmetry, we obtain the range of the mass of dark matter particles as $56~{\rm~GeV}\lesssim~m_S\lesssim~63~{\rm~GeV}$ or $m_S\gtrsim450~{\rm~GeV}$, based on the dark energy-dark matter coupling term from multiple measurements of quasars. Such conclusions agree well with the latest experimental results aimed at the direct detection of dark matter particles.

Formation of primordial black holes after Starobinsky inflation

In this paper, we adapted the Appleby–Battye–Starobinsky model of [Formula: see text] gravity towards describing double cosmological inflation and formation of primordial black holes with masses up to [Formula: see text] g in the single-field model. We found that it is possible to get an enhancement of the power spectrum of scalar curvature perturbations to the level beyond the Hawking (black hole evaporation) limit of [Formula: see text] g, so that the primordial black holes resulting from gravitational collapse of those large primordial perturbations can survive in the present universe and form part of cold dark matter. Our results agree with the current measurements of cosmic microwave background radiation within [Formula: see text] but require fine-tuning of the parameters.

Radioactive background radiation measurement in Mureş county

Abstract From the beginning, there has always been radiation in the Universe. Most people are unaware of it, even though it is around us all the time, and can have many negative effects on our bodies. In the long term, it can lead to the development of various diseases. The natural background radiation includes cosmic radiation, plus radiation from radioactive elements present in the soil, atmosphere, and living organisms. A significant, measurable fraction of this is gamma radiation. Artificial radioactive isotopes can be used in a variety of applications, such as space research, sterilization, and medical diagnostic imaging. Our objective is to measure the dose equivalent rate from the gamma fraction of background radiation in Mureş county, in open and closed spaces, and in frequently visited areas. The measurements were performed with a Gamma Scout dosimeter. The measured average dose equivalent rates are 0.104 µSv/h in Târgu Mureş, 0.111 µSv/h in Reghin, 0.112 µSv/h in Sovata, 0.091 µSv/h in Tarnaveni, 0.095 µSv/h in Ludus and 0.067 µSv/h in the Upper-Mureş Nature Park. Based on the measurements, the calculated mean annual dose is 0.884 mSv/year. According to the data based on the measurements, the dose equivalent rates measured in Mureş county do not pose a risk to our health.

Total power horn-coupled 150 GHz LEKID array for space applications

We have developed two arrays of lumped element kinetic inductance detectors working in the D-band, and optimised for the low radiative background conditions of a satellite mission aiming at precision measurements of the Cosmic Microwave Background (CMB) radiation. The first detector array is sensitive to the total power of the incoming radiation to which is coupled via single-mode waveguides and corrugated feed-horns, while the second is sensitive to the polarisation of the radiation thanks to orthomode transducers.Here, we focus on the total power detector array, which is suitable, for instance, for precision measurements of unpolarised spectral distortions of the CMB, where detecting both polarisations provides a sensitivity advantage. We describe the optimisation of the array design, fabrication and packaging, the dark and optical characterisation, and the performance of the black-body calibrator used for the optical tests. We show that almost all the detectors of the array are photon-noise limited under the radiative background of a 3.6 K black-body. This result, combined with the weak sensitivity to cosmic ray hits demonstrated with the OLIMPO flight, validates the idea of using lumped elements kinetic inductance detectors for precision, space-based CMB missions.

Development of a standard method for primary monitoring of exposure to environmental radiation

All living things are constantly exposed to background radiation. The presence of radioactive materials in the earth's crust and cosmic radiation are largely responsible for this exposure. The present study aimed to develop a new methodology of easy applicability and low cost to carry out measurements of environmental background radiation and to be able to establish a map of environmental radiation for primary monitoring of these exposures. For that, ionizing radiation measurements, Meteorological and Radiometric measurements were performed. Geiger Mueller Counter (GM) was used, as it is widely used in services that use radioactive sources and research centers. Measurements obtained showed that there were no statistically significant changes in the 24 hours of measurements with the GM, in relation to the variations presented in the Meteorological and Radiometric measurements that changed according to the time of day. The average value of the background radiation readings was 0.0194 mR/h, with an average variance of 1.8E-06 and an average standard deviation of 1.35E-03. GM proved to be useful for primary measurement of background radiation. The map was developed using open source libraries for the Python programming language. The map may be hosted on an open access website, so that professionals, students and researchers may contribute, sending new data from different locations. It is essential that the levels of radiation exposure are demonstrated and understood. Easy access to this information may contribute to health organizations, agriculture and research centers to establish a baseline for future research.

Superhorizon Perturbations: A Possible Explanation of the Hubble–Lemaître Tension and the Large-scale Anisotropy of the Universe

Abstract Current cosmological observations point to a serious discrepancy between the observed Hubble parameter obtained using direct versus cosmic microwave background radiation measurements. Besides this so-called Hubble–Lemaître tension, we also find considerable evidence in diverse cosmological observables that indicate violation of the cosmological principle. In this paper, we suggest that both these discrepancies are related and can be explained by invoking superhorizon perturbations in the universe. We implement this by considering a single superhorizon mode and showing that it leads to both a dipole in large-scale structures and a shift in the Hubble–Lemaître parameter. Furthermore, the shift is found to be independent of redshift up to a certain distance. This is nicely consistent with the data.

Exploring the parameter space of modified supergravity for double inflation and primordial black hole formation

We study the parameter space of the effective (with two scalars) models of cosmological inflation and primordial black hole (PBH) formation in the modified (R + R 2) supergravity. Our models describe double inflation, whose first stage is driven by Starobinsky’s scalaron coming from the R 2 gravity, and whose second stage is driven by another scalar belonging to the supergravity multiplet. The ultra-slow-roll regime between the two stages leads a large peak (enhancement) in the power spectrum of scalar perturbations, which results in efficient PBH formation. Both inflation and PBH formation are generic in our models, while those PBH can account for a significant part or the whole of dark matter. Some of the earlier proposed models in the same class are in tension (over 3σ) with the observed value of the scalar tilt n s, so that we study more general models with more parameters, and investigate the dependence of the cosmological tilts (n s, r) and the scalar power spectrum enhancement upon the parameters. The PBH masses and their density fraction (as part of dark matter) are also calculated. A good agreement (between 2σ and 3σ) with the observed value of n s requires fine tuning of the parameters, and it is only realized in the so-called δ-models. Our models offer the (super)gravitational origin of inflation, PBH and dark matter together, and may be confirmed or falsified by future precision measurements of the cosmic microwave background radiation and PBH-induced gravitational waves.

Estimated measurements of natural background radiation in the surface atmospheric layer of the Almaty region

The radon isotopes of natural radioactive radiation of the earth’s crust emanating to the surface areconcentrated in the human environment and have a direct impact on the people health. Due to this factthe problem of studying the radiation distributions in the surface atmospheric layer of the Earth is urgent.In this work, measurements of the exposure dose rate, beta particle flux, and equivalent equilibriumvolumetric activity (EEVA) of radon in the surface atmospheric layer of the Earth have been performed.Measurements of radon and gamma, beta backgrounds were carried out from April 2021 to August 2021in the Almaty region at various altitudes above sea level: from 500 to 2500 meters. They were carried outusing electronic radiometric equipment: beta-dosimeter “RKS-01B-SOLO”; gamma dosimeter “RKS-01GSOLO”;radiometer of radon-222 “RAMON-02” in the field. As a result, preliminary assessment schemeswere built for route measurements of the 222Rn radon isotope, beta and gamma radiation fields fromnatural daughter products of decay of radon isotopes and radionuclides located in the surface atmosphericlayer. As a result of this work, an altitude dependence of changes in the natural radiation gamma and betabackground of the surface surface layer is presented, which grows with an increase in the surface above sealevel. The different activity of radon over rocks and soils is shown, which, as is known, is associated withthe exhalation of radon and which depends, among other things, on the density of the soils. The preliminaryresults of measurements of significant perturbations of the EEVA of radon did not reveal. Key words: variations in time of radon; natural beta active radionuclides; coagulation; atmospheric radioactive, nanoparticles.

Evaluation of Risk Factors for Pediatric Cancers in the West of Iran

Background: Occurrence of pediatric cancers is affected by maternal, environmental, and hereditary/genetic factors. Objectives: The purpose of this study was to evaluate the correlation between background radiation, ultrasound and other possible risk factors for pediatric cancers incidence indicators. Methods: In a cross-sectional study during 2 years, 103 patients under 14 years were studied. A total of 13 environmental, maternal and hereditary/genetic risk factors were studied, and the study was performed by using a questionnaire, measurement of background radiation, and statistical data. Incidence in the studied sample size at city (ISSSC) and incidence in the studied sample size at area (ISSSA) indicators were defined. Results: The mean age of patients was (6.31 ± 3.22) including 54 (52.4%) males and 49 (47.6%) females. History of repeated ultrasound before gender determination (RUBGD) and repeated ultrasound during pregnancy (RUDP) were statistically higher in solid tumors group. Toxic substances (TS) and pediatric medical ionizing radiation (PMIR) was higher in hematologic malignancies. Statistically significant association were found between of cancer types and Family history of leukemia (FHL), Family history of solid tumors (FHST), Abortion history (AH), Maternal smoking during pregnancy (MSDP), Children’s residence place (CRP), and background radiation (BR) variables. No statistically significant association was found between cancer types and maternal pregnancy age (MPA), IVF baby, and maternal ionizing radiation exposure (MIRE) variables. Conclusions: Pediatric cancers are multifactorial diseases. Increased background radiation is correlated with an increased incidence of all pediatric malignancies. It seems that increasing ultrasound scans might increase the risk of solid tumors in children.

Procedimiento didáctico para el estudio de la fórmula de Planck en carreras de ingeniería

En este artículo se analiza la ley de distribución de energía en el espectro de la radiación del cuerpo negro, y la fórmula de Planck que la sintetiza, un descubrimiento revolucionario, que marca el nacimiento de la teoría cuántica. Se propone un procedimiento didáctico para el estudio de la fórmula de Planck en carreras de ingeniería, siguiendo la secuencia del ciclo de la creación científica: Hechos → Modelo-hipótesis → Consecuencias → Verificación experimental. Se ejemplifican los pasos metodológicos y los elementos esenciales de la idea básica de la cuantización de la energía, con notas históricas que facilitan la comprensión del fenómeno estudiado y el papel que jugaron los científicos en su determinación. Se consideran hechos iniciales: Las leyes de Kirchhoff, Stefan-Boltzmann y Wien, además de la fórmula de Rayleigh-Jeans y se desarrollan las ideas fundamentales que permitieron a Planck encontrar la solución teórica, que culmina en 1900 con la propuesta del cuanto de acción, expresado por la constante h que lleva su nombre. De la fórmula de Planck, se deducen las leyes antecedentes y se obtienen otras relaciones de importancia para la física y la química. Para cerrar el ciclo de la creación científica, se realiza la verificación experimental, con la medición de la radiación de fondo cósmico, que se comporta como la radiación de un cuerpo negro a una temperatura de 2,73 K. Se concluye con ejemplos de aplicaciones de la radiación térmica, que involucran algunos conceptos básicos de la elaboración teórica de Planck: Energía solar, recubrimientos térmicos y pirometría.

Human exposure levels to ionizing radiation in Agbara Industrial Estate: an impact of Industrial activities in Nigeria.

A total of fifty-five soil samples were collected from four locations, namely, residential, industrial, dumpsite, and sewage in Agbara industrial estate, Ogun state, Nigeria. The samples were analyzed using a high purity germanium detector (HPGe) to measure the activity concentration of radionuclides. Background radiation measurements were also taken at each point where soil samples were collected using Geiger Muller (GM) counter. The mean activity concentrations measured in the soil samples were 171.33 for 40K, 9.11 for 232Th, and 5.05 for 226Ra in Bq/kg. The mean absorbed dose rate in the air due to radionuclides (40K, 232Th, and 226Ra) in the soil is calculated to be 14.77 nGy/h, and the mean annual effective dose equivalent (AEDE) is 0.02 mSv/year. The mean equivalent dose rate (EDR) from GM counter for background radiation is 0.22 μSv/h, and the mean annual effective dose rate (AEDR) is 0.39 mSv/year. These values are below the world average values, except EDR and AEDR with mean values higher than the world standard. The comparison of radiation dose rates revealed that radionuclides contributed 6.7% to background radiation. The equivalent dose (EDorgans) for various organs of the body was calculated, and results showed that values do not pose any immediate health hazard. The excess lifetime cancer risk (ELCR) due to exposure to background radiation indicated that the dwellers and industrial workers in the study area may develop cancer over a lifetime due to accumulated dose.