Environmental Background Radiation Research Articles

Canfranc biology platform: exploring life in cosmic silence

Deep underground laboratory infrastructures have extensively been used for exploring rare events, such as proton decay, dark matter searches or neutrino interactions, taking advantage of their large muon flux reduction. However, only very few investigations have evaluated the effects of low background radiation environments on living organisms. With this purpose, the Canfranc Underground Laboratory (LSC) launched the Biology Platform in 2021, which provides lab space for approved biology experiments. Two identical laboratories have been built (underground and on surface) to replicate biology experiments under the same conditions, with the main difference being the cosmic radiation background. The access protocol to use the LSC facilities includes two open calls per year and assigned time windows for executing the experimental program, which led to the first eight approved and already running experiments. We describe the scientific program of the Canfranc Biology Platform, which explores extremophiles, viral infection, immune system, multicellularity, development or aging in cosmic silence, and the first experimental results. The Platform also allows to observe the response of life to microgravity in absence of radiation, a key condition to explore life in space.

Overview of DISCOVER22 experiment in the framework of INFN-LNGS Cosmic Silence activity: challenges and improvements in underground radiobiology

One of the most intriguing and still pending questions in radiobiology is to understand whether and how natural environmental background radiation has shaped Life over millions of years of evolution on Earth. Deep Underground Laboratories (DULs) represent the ideal below-background exposure facilities where to address such a question. Among the few worldwide DULs, INFN-Laboratorio Nazionale del Gran Sasso (LNGS) is one of the largest in terms of size and infrastructure. Designed and built to host neutrino and dark matter experiments, since the 1990 s the LNGS has been one of the first DULs to systematically host radiobiology experiments. Here we present the DISCOVER22 (DNA Damage and Immune System Cooperation in VEry low Radiation environment 2022) experiment recently started at LNGS. DISCOVER22 aims at investigating how the low radiation background modulates the Immune System (IS) response in in vitro and in vivo models. Underground radiobiology experiments are particularly complex and tricky to design and perform. In these studies, the accurate characterization of exposure scenarios is mandatory, but a challenging aspect is to understand how the very few ionizing tracks in the ultra-Low Radiation Environment (LRE) interact with the living matter in space and time in order to trigger different biological responses. In this Perspective, we describe these challenges and how we address them through a microdosimetric and a radiobiological approaches. We aim at linking physical microdosimetric measurements and the corresponding biological radiation responses by using radiation biophysical models that could shed light on many as yet unresolved questions.

High granularity resistive Micromegas for high particle rates environment

The new era of particle physics experiments is moving towards new upgrades of present accelerators (Large Hadron Collider at CERN) and the design of high energy (tens/hundreds TeV scale) and very high intensity new particle accelerators (FCC-ee/hh, EIC, Muon Collider). Cost effective, high efficiency particle detection in a high background and high radiation environment is fundamental to accomplish their physics program. We present a new high granularity resistive Micromegas detector capable to ensure full efficient and stable operation and a good tracking capabilities up to particle fluxes of 10 MHz/cm2. A summary of the detector performances, measured by mean of high intensity X-ray, muon and pion sources, is reported, together with most recent results from test beam activities.

Analysis of Atmospheric Radiosulfur at Natural Abundance by a New-Type Liquid Scintillation Counter Equipped with Guard Compensation Technology

High-sensitivity measurements of radiosulfur (cosmogenic 35S; half-life: 87.4 days) at natural abundance using ultra-low-level liquid scintillation counter (LSC) methods have been developed and optimized in the last decade, providing new details in space, atmospheric, and hydrological sciences. These LSC methods heavily rely on instruments conventionally equipped with 650 kg lead blocks that passively shield cosmic and environmental background radiation, but this type of instrument is not commercially available anymore, hindering further applications of 35S. To solve this problem, we extended the methods to a new-type LSC equipped with new mathematics-based active shielding techniques (Guard Compensation Technology; GCT). The counting efficiency of the new-type LSC for low-35S activity samples (e.g., natural samples) is low and highly variable because a portion of true signals from 35S decay events was undesirably removed by GCT. We therefore developed a new data processing protocol to determine 35S activities accurately and precisely in the range between ∼1 and ∼13 disintegrations per minute, and its validity was tested by working standards with known 35S activities. As an application example, we measured concentrations of 35S in sulfate aerosols collected in Guangzhou, a megacity in subtropical South China. The obtained values are within the range of previously reported data from various mid-latitude sampling sites. Based on these results, we conclude that our protocol allows the continuing utility of 35S measurements using a new-type LSC for a deeper understanding of the atmospheric sulfur cycle and its influences on the environment, climate, and public health.

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.

Design and Realization of China Tianwen-1 Energetic Particle Analyzer

The Mars radiation environment, both in past and at present, plays a vital role in the evolution of Martian atmosphere, so it is necessary to detect the background radiation environment both in the Martian atmosphere and the transfer orbit from Earth to Mars. The Tianwen-1 Energetic Particle Analyzer (EPA) is designed to measure and analyze the energetic charged particles emitted to the Martian atmosphere. Mars-EPA consists of two parts: one is the Mars-EPA sensor head and the other is the Mars-EPA electronics system. This paper begins with an introduction of Mars-EPA structure and function of each part, followed by a simulation of how sensor head structure is designed. It then evaluates the performance of detection system using Geant4 software, to whether this sensor is capable of identifying the target particle and proposes a reasonable ground calibration procedure, which allows on overall detection performance to some degree. This Mars-EPA has demonstrated a potentially high capability and configurability which hopefully will shed light on future development of compact energetic detectors in deep space exploration.

The presence of radioactive materials in soil, sand and sediment samples of Potenga sea beach area, Chittagong, Bangladesh: Geological characteristics and environmental implication

Abstract Accurate quantification of naturally occurring radioactive materials in soil provides information on geological characteristics, possibility of petroleum and mineral exploration, radiation hazards to the dwelling populace etc. Of practical significance, the earth surface media (soil, sand and sediment) collected from the densely populated coastal area of Chittagong city, Bangladesh were analysed using a high purity germanium γ-ray spectrometer with low background radiation environment. The mean activities of 226Ra (238U), 232Th and 40K in the studied materials show higher values than the respective world average of 33, 36 and 474 Bq/kg reported by the UNSCEAR (2000). The deduced mass concentrations of the primordial radionuclides 238U, 232Th and 40K in the investigated samples are corresponding to the granite rocks, crustal minerals and typical rocks respectively. The estimated mean value of 232Th/238U for soil (3.98) and sediment (3.94) are in-line with the continental crustal average concentration of 3.82 for typical rock range reported by the National Council on Radiation Protection and Measurements (NCRP). But the tonalites and more silicic rocks elevate the mean value of 232Th/238U for sand samples amounting to 4.69. This indicates a significant fractionation during weathering or associated with the metasomatic activity in the investigated area of sand collection.

Web‐based visual data exploration for improved radiological source detection

SummaryRadiation detection can provide a reliable means of detecting radiological material. Such capabilities can help to prevent nuclear and/or radiological attacks, but reliable detection in uncontrolled surroundings requires algorithms that account for environmental background radiation. The Berkeley Data Cloud (BDC) facilitates the development of such methods by providing a framework to capture, store, analyze, and share data sets. In the era of big data, both the size and variety of data make it difficult to explore and find data sets of interest and manage the data. Thus, in the context of big data, visualization is critical for checking data consistency and validity, identifying gaps in data coverage, searching for data relevant to an analyst's use cases, and choosing input parameters for analysis. Downloading the data and exploring it on an analyst's desktop using traditional tools are no longer feasible due to the size of the data. This paper describes the design and implementation of a visualization system that addresses the problems associated with data exploration within the context of the BDC. The visualization system is based on a JavaScript front end communicating via REST with a back end web server.

Modeling background radiation in Southern Nevada

Aerial gamma ray surveys are an important tool for national security, scientific, and industrial interests in determining locations of both anthropogenic and natural sources of radioactivity. There is a relationship between radioactivity and geology and in the past this relationship has been used to predict geology from an aerial survey. The purpose of this project is to develop a method to predict the radiologic exposure rate of the geologic materials by creating a high resolution background model. The intention is for this method to be used in an emergency response scenario where the background radiation environment is unknown. Two study areas in Southern Nevada have been modeled using geologic data, images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), geochemical data, and pre-existing low resolution aerial surveys from the National Uranium Resource Evaluation (NURE) Survey. Using these data, geospatial areas that are homogenous in terms of K, U, and Th, referred to as background radiation units, are defined and the gamma ray exposure rate is predicted. The prediction is compared to data collected via detailed aerial survey by the Department of Energy's Remote Sensing Lab - Nellis, allowing for the refinement of the technique. By using geologic units to define radiation background units of exposed bedrock and ASTER visualizations to subdivide and define radiation background units within alluvium, successful models have been produced for Government Wash, north of Lake Mead, and for the western shore of Lake Mohave, east of Searchlight, NV.

Failure of Real-time Passive Notification about Radiation Exposure to Influence Physician Ordering Behavior.

Objectives To determine whether real-time passive notification of patient radiation exposure via a computerized physician order entry system would alter the number of computed tomography scans ordered by physicians in the Emergency Department (ED) setting.Methods When a practitioner ordered a computed tomography scan, a passive notification was immediately and prominently displayed via the computerized physician order entry system. The notification stated the following: the amount of estimated radiation in millisieverts (mSv), the equivalent number of single-view chest radiographs, and equivalent days of average environmental background radiation to which a patient during a specific computed tomography scan would be exposed. The primary outcome was changed in the number of computed tomography scans ordered when comparing data collected before and after the addition of the notification.Results Before the dosimetry notification (“intervention”) was instituted, 1,747 computed tomography scans were performed on patients during 11,709 Emergency Department visits (14.9% computed tomography scan rate). After the intervention had been instituted, 1,827 computed tomography scans were performed on patients during 11,582 Emergency Department patient visits (15.8% computed tomography scan rate). No statistically significant difference was found for all chief complaints combined (p = 0.17), or for any individual chief complaint, between the number of computed tomography scans performed on Emergency Department patients before versus after the intervention.Conclusions Passive real-time notification of patient radiation exposure displayed in a computerized physician order entry system at the time of computed tomography scan ordering in the Emergency Department did not significantly change the number of ordered scans.

Evaluation of Radio-Photoluminescence Spectra of Copper-Doped Phosphate Glass Dosimeter Irradiated with Ionized Particles

A radio-photoluminescence (RPL) dosimeter with a copper-ion luminescent center was fabricated to evaluate its response in ionized particle detection. A focused proton microbeam with varying energies up to 3 MeV and heavy ions of 490 MeV osmium (Os) were employed along with X-rays to evaluate its performance in micrometer-scale radiation monitoring. The response to ionized particles was evaluated under focused proton beam irradiation where the peak wavelength differed from that obtained under X-ray irradiation. Two peaks were observed under Os irradiation where the secondary-generated particles and photons have a significant effect on the dosimeter. The results suggest that the fabricated RPL dosimeter with copper luminescence center could be used to estimate the irradiation effect of primary ionized particles separately from the effects of secondary particles, photons, and environmental background radiation.

Development of environmental radiation monitoring system using inspector+ and FPGA board

In this report, we present the development of an environmental radiation monitoring system. The system includes Inspector+ dose meter, FPGA board, and LabVIEW interface. In the electronic board using FPGA, the embedded VHDL program is developed for FPGA board. Its functions are to accumulate pulse signals from the Inspector+, transmit data to the computer. Computer interface is written on LabVIEW platform. Its functions are to receive data from FPGA board, plot data, store data, as well as control the FPGA board. We evaluate the response of the system by using a standard pulse generator. With this system, we carry out the measurement of environmental background radiation in two experimental rooms and outside at Nuclear physics Department, University of Science, VNU-HCMC.

Assessment of Effective Dose Equivalent from Internal Exposure to 222Rn in Ramsar City

Introduction In this study, effective dose equivalent for the public due to internal exposure to 222radon (222Rn) was evaluated in three regions of Ramsar, a northern coastal city in Iran. Materials and Methods Measurements were carried out using a radon monitoring device. Outdoor and indoor radon concentrations were measured within 24 hours with an integration interval of 3 hours. Regions were selected with respect to our previous study on areas of Ramsar with high levels of environmental background radiation. Results This study showed that indoor 222Rn concentration reached to 465 Bq/m3 in one of the selected regions (Talesh Mahalleh) in early morning (5-8 a.m.). Our study also showed that the average effective dose equivalents (due to both indoor and outdoor exposures) in the selected regions (Talesh Mahalleh, Sadat Mahalleh, and Chaparsar) were 9.5±2.8, 5.1±2.1, and 3.2±1.2 mSv/y, respectively. Conclusion It is clear that the annual effective dose from internal exposure to 222Rn in areas of Ramsar with high levels of natural radiation was significantly higher than the maximum annual effective dose permissible for public.

Performance of some handheld dosimeters used for gamma-ray ambient dose rate measurements

A study was carried out on the performance of some handheld dosimeters that are used for measuring ambient gamma dose rates. A CsI scintillation-based and two GM-based dosimeters were used to measure the absorbed dose rates in an indoor environment, inside a lead shield, on different floors of a building, in a desert environment and in a boat on the Arabian Gulf. The study showed that while some instruments provide measurements of ambient gamma dose rates, which include contributions from both terrestrial and cosmic radiation components, others show the terrestrial/indoor gamma dose rate only. Tests also showed that some dosimeters may fail to operate in the very low background radiation environments unless a radioactive source is used for the start-up.

Evaluation of High Level Environmental Background Radiation Areas and its Variation in Ramsar

Introduction The exposure of human beings to ionizing radiation from natural sources is a continuing and inescapable feature of life on earth. For most individuals, this exposure exceeds that from all man-made sources combined. Materials and Methods In this study, the annual effective dose in high level environmental background radiation areas (HLEBRAs) of northern city of Ramsar in Iran was determined. For dosimetry, a gamma radiation dosimeter was used. Measurements were performed in more than 90 points in five districts with HLEBR around and near hot springs. Results In some areas, the annual effective dose from outdoor external gamma radiation in HLEBRAs (30 mSv/y) exceeded the annual effective dose limit for radiation workers. Our results are evident that the population dose from normal background radiation in HLEBRAs is 200 times higher than corresponding values in Ramsar sea shore. To estimate the cosmic ray contribution, dose measurements were performed on the sea surface one km off the sea shore. Conclusion The observed differences over locations and measured doses between this study and the others revealed the dynamic nature of this phenomenon, and necessitate performing the periodic studies in these areas. Moreover, cytogenetic and immunologic researches for studying the long term effects of these high level environmental radiations on the residents of these HLEBRAs are necessary.

Differential proteome analysis of a selected bacterial strain isolated from a high background radiation area in response to radium stress

The present study describes the response of a bacterial strain, isolated from a hot spring in an area with the highest levels of natural radiation, under radium ((226)Ra) stress. The bacterium has been characterized as a novel and efficient radium biosorbent and identified as a variant of Serratia marcescens by biochemical tests and molecular recognition. In order to gain insights into key cellular events that allow this strain to survive and undergo (226)Ra adaptation and biosorption, the strain was tested under two experimental conditions of 1000 and 6000 Bq (226)Ra stress. A proteomic approach involving two-dimensional polyacrylamide gel electrophoresis and mass spectrometry was used to identify the differentially expressed proteins under (226)Ra stress. Functional assessment of identified proteins with significantly altered expression levels revealed several mechanisms thought to be involved in (226)Ra adaptation and conferring resistant phenotype to the isolate, including general stress adaptation, anti-oxidative stress, protein and nucleic acid synthesis, energy metabolism, efflux and transport proteins. It suggests that this strain through evolution is particularly well adapted to the high background radiation environment and could represent an alternative source to remove (226)Ra from such areas as well as industrial radionuclide polluted wastewaters.

The use of pKZ1 mouse chromosomal inversion assay to study biological effects of environmental background radiation

Life has evolved on Earth for 3 billion years in the presence of background ionizing radiation (IR). All organisms on Earth are continuously exposed to varying amounts of natural radiation and they have therefore incorporated in their normal biology a daily stimulus of ultra-low-dose radiation. A question arises about the biological effects of environmental background radiation and whether the biochemical behavior of living organisms would differ if it was absent. Here, we report our experimental design to address these scientific questions, which use pKZ1 mouse chromosomal inversion assay to study the biological behavior of different cell cultures maintained in “cosmic silence” and in reference background conditions.

Aerosol nucleation in an ultra-low ion density environment

Ion-induced nucleation has been studied in a deep underground ultra-low background radiation environment where the role of ions can be distinguished from alternative neutral aerosol nucleation mechanisms. Our results demonstrate that ions have a significant effect on the production of small sulfuric acid–water clusters over a range of sulfuric acid concentrations although neutral nucleation mechanisms remain evident at low ionization levels. The effect of ions is found both to enhance the nucleation rate of stable clusters and the initial growth rate. The effects of possible contaminations are also discussed and are believed to be small, but cannot be excluded. If our results can be extrapolated to conditions that resemble the clean air atmosphere over the Earth's oceans they suggest that ions may dominate the production of small (4nm) aerosols here.

Infrared imaging characteristics of space-based targets based on bidirectional reflection distribution function

A modeling method of infrared imaging characteristics of a space-based target was presented. Background radiation environment of a space-based target was analyzed and the background radiation mainly consists of direct radiation of the sun, thermal radiation and reflected radiation of the earth. The target surface was divided into regions based on geometrical shape and surface material characteristics and a surface equation of each region was built based on its body coordinate system. Each region was divided into meshes supposing that each mesh is a micro-plane. A bidirectional reflection distribution function (BRDF) model considering the characteristics of surface Gauss statistics and self-shadow was introduced to describe reflected infrared of each mesh of the target surface. The emitted infrared radiation of each mesh of the target surface was described according to its thermal equilibrium temperature. Then a mathematical model on infrared radiation imaging characteristics of the space-based target was built in terms of the given infrared detector. The relative positions of the space-based target, the background radiation sources and the detector are determined by orbital parameters based on coordinate conversion. Visual surfaces of the target to observation system were determined by vector coordinate method. Simulation of optical imaging characteristics of the target in orbit was achieved according to its given geometrical dimensions and physical parameters. The results show the method is feasible and robust for infrared characteristics of the space-based target when single reflection is considered and its surface is regular and can be described in a surface equation. It can provide a facility to real-time analysis of infrared imaging characteristics of the space-based targets.

Development of Pattern Recognition Software for Tracks of Ionizing Radiation In Medipix2-Based (TimePix) Pixel Detector Devices

The principal aim of our project is to develop an efficient pattern recognition tool for the automated identification and classification of tracks of ionizing radiation as measured by a TimePix version of the hybrid semiconductor Medipix2 pixel detector system. Such a software tool would have a number of applications including dosimeters to assess the risk of human exposure to radiation, and area monitors to characterize the general background radiation environment harmful to humans and electronic equipment. We are particularly interested in the development of the real-time analysis software needed to support an operational dosimeter that can assess the radiation environment during space missions. Our software development project makes use of data taken in beams of heavy ions at HIMAC (Heavy Ion Medical Accelerator Facility) in Chiba, Japan, including data from several different heavy ions with similar Linear Energy Transfers (LETs) for calibration purposes. We describe two modules of our pattern recognition tool: feature generation and classification. Our first module builds on a segmentation algorithm that identifies tracks from the pixel image assuming an approximately elliptical form that varies in size and degree of elongation based on multiple factors, including the particle species and angle of incidence. Determining the charge and energy of the particles creating each track is a particularly challenging task because different energy and charge incident particles can produce very similar patterns. Our classification module invokes different algorithms such as decision trees, support vector machines, and Bayesian classifiers.