Radiation Detection

With the radiation sources widely used in the field of industry, agriculture, medicine, and resources all over the world, the occurrences of the lost and theft incidents are not unusual. There will be great threats to human health and environment for uncontrolled sources. It can be even worse when they are used by terrorists as weapons in the city, such as RDD, which would disperse the radioactive substances into the environment and have a long-term negative impact on human society. Besides the security control and surveillance of radiation sources, the source-searching method using radiation detectors is also needed to find the lost or stolen sources. In the case of radiation monitoring in a city, a mass of people with detectors are needed to cover the large area, while radiation dosimeters are appropriate for its portability and economy. In this paper, a simple approach to finding and locating unknown radiation sources, which might be in static or mobile condition, using distributed mobile radiation dosimeters is put forward. This approach is able to estimate the time-dependent sources location and the intensity with the dose rate measurements over time periods. Random data is introduced to verify the approach. Virtual radiation sources and detectors with random movement are created in the cases and the dose rate measurements are computed accordingly, with which sources location and intensity are estimated, where natural background radiation and the statistical fluctuation of measurements are taken into account. The results of the estimated sources show a good consistency with the assumptions.

The technical details of a radiation measuring system based on a quartz torsion fiber electroscope and a pressurized ionization chamber are described. This equipment is designed to measure the radiation intensity from the carbon-14 contained in a sample introduced into the system as carbon dioxide. This system, including the shielding, is shown to be capable of measuring nuclear radiations of extremely low intensities, on the order of 1/200 of the normal laboratory background level, with a probable error of approximately l%. The background radiation intensity observed with the system including the shielding is also on the order of 1/200 of the normal laboratory background level. The nature of background radiation and its relation to the measurement of such low intensities is discussed. It is shown that the main limitation in accuracy, with the equipment described here, is due to cosmic ray bursts. It is also shown that the major source of background radiation is external to the equipment, being thus due to cosmic rays and/or local external gamma ray emitting material contamination. Although the evidence is not conclusive, the data indicates in addition that the cosmic rays are the major contributor to this background radiation. The main conclusion which may be drawn from these results is that the selection of an equipment location is very effective in reducing the level of background radiation, thus permitting the measurement of radiation fields of extremely low intensity. The final application of this equipment was to the well known carbon-14 dating method originated by W. F. Libby. Several samples of interest were dated and the results are given. Of particular interest, are the samples from the Santa Rosa Islands off the California Coast, concerning an Indian culture which existed there before Christ and after.

The detection and measurement of radiation is based on the interaction of radiations with matter discussed in Chap. 1. In gases, ionizing radiations, particulate or electromagnetic, interact with gas molecules to produce positive and negative ions, which are then collected as current or count by the application of a voltage. The amount of ionization is proportional to the amount of energy deposited by the radiation. At low voltages, the ionization is measured as current that is proportional to the amount of radiation. Dose calibrators, pocket dosimeters, and ionization chambers operate on this principle at low voltages (∼ 150 V). At high voltages (∼ 900 V), ions are multiplied in an avalanche of interactions producing a pulse that is independent of the energy and type of radiation. Each event of interaction is detected as a count, and this principle is applied in Geiger–Muller (GM) counters, which are used as radiation survey meters.

To ensure safely operation and maintenance for NNBI laboratory personnel, the neutron radiation in NNBI deuterium-charged operation was studied. That can provide some guidance for shielding design. In order to master the radiation dose of NNBI during the operation and shutdown timely, it is necessary to design a suitable system to measure the NNBI radiation. Therefore, it can guide the worker and maintenance personnel to work safely. Due to the complexity of NNBI's geometric structure and physical process, the neutron source strength radiation dose at the critical position of NNBI are evaluated based on the LMM local model and MCNP code. The results demonstrate that the calorimeter is the main neutron source region. When the deuterium ion energy is 400keV and the pulse is greater than 100s, and the neutron intensity of the target is 1E+12n/(A · s). The maximum radiation dose rate can reach up to 1E+08 μSv/h. For such a high radiation dose rate, An appropriate radiation measurement methods need to be designed. The design of radiation measurement based on Rob robot mobile platform can effectively reduce the harm of radiation to maintenance personnel.

Portable radiation detectors are widely used in environmental radiation detection and medical imaging due to their portability feature, high detection efficiency, and large field of view. Lutetium-yttrium oxyorthosilicate (LYSO) is a widely used scintillator in gamma radiation detection. However, the structure and the arrangement of scintillators limit the sensitivity and detection accuracy of these radiation detectors. In this study, a novel portable sensor based on a monolithic LYSO ring was developed for the detection of environmental radiation through simulation, followed by construction and assessments. Monte Carlo simulations were utilized to prove the detection of gamma rays at 511 keV by the developed sensor. The simulations data, including energy resolutions, decoding errors, and sensitivity, showed good potential for the detection of gamma rays by the as-obtained sensor. The experimental results using the VA method revealed decoding errors in the energy window width of 50 keV less than 2°. The average error was estimated at 0.67°, a sufficient value for the detection of gamma radiation. In sum, the proposed radiation sensor appears promising for the construction of high-performance radiation detectors and systems.

We once saw a science fiction movie in which a monster from outer space is first detected because it sets Geiger counters clicking furiously. We were reminded of that movie by the story of how radon in homes first came to wide public attention. A nuclear power plant was built in a town in Pennsylvania, and like all such plants was equipped with radiation detectors, both to protect the health of employees and to prevent anyone from removing nuclear fuel from the plant. A newly employed engineer at the plant registered a high radioactivity when he walked by the detectors. This was not only alarming but surprising: the plant was not yet operating, and there should not have been any radioactive material around. It was quickly established that the source of the radiation was not the plant but the engineer’s house in a nearby suburban community, which had levels of radioactivity almost a thousand times greater than federal standards permit in mines. The radioactivity came from radon gas seeping into the house from the ground. Cigarette smoking is responsible for about 90% of lung cancers, but 10% of the victims of this disease had never smoked. It was already known that miners exposed to radon gas in uranium mines suffered a high rate of lung cancer, and the question immediately arose: could radon gas in homes be another cause of lung cancer? Radon in homes is not a consequence of the atomic bomb or the building of nuclear power plants; it is one of the major sources of the natural background radiation we are all exposed to. It is present even in outdoor air, and at higher concentrations in homes, castles, peasants’ hovels, and caves as long as people have lived in them. It is a product of the decay of the element uranium. Uranium is present to some extent in all minerals, so we expect to find more radon in houses built of stone or mineral products like stone, concrete, and gypsum than in houses built of wood, and we expect to find more of it in basements than in attics.

Introductory Concepts. Forces and Energy in Atoms. Major Discoveries in Radiation Physics. Interactions. Radioactive Transformation. Naturally Occurring Radiation and Radioactivity. Interactions of Radiation with Matter. Radiation Shielding. Production of Activation Products. Nuclear Fission and Its Products. Nuclear Criticality. Radiation Detection and Measurement. Statistics in Radiation Physics. Neutrons. X Rays. Appendices. Answers to Selected Problems. Index.

We propose a system for remote measurement of low-energy radiation, which is implemented using an ARM board and a ZigBee module. The ARM STM32F103 board employs a horizontal and vertical moving CMOS camera for front-end data acquisition. The camera can detect radiation over different coordinates given by latitude and longitude in a determined area. For image processing, we used the subtraction–summation algorithm based on gradient multiplication and edge detection. Compared to algorithms such as the max grayscale value, subtraction–summation, and whole summation, the improved subtraction–summation algorithm filters noise and removes the background grayscale value of the whole image to attain higher accuracy, stronger anti-interference ability, and better consistency to determine the radiation dose. We dedicated one port of the transmission module to send data through the STM32F103 board, whereas another port is connected to the ZigBee module for data reception. By employing this architecture, we achieved low power consumption and fast response in the remote data transmission. Overall, the proposed system performs the remote measurement of low-energy radiation with stability and reliability, which is required for critical scenarios such as the remote detection of nuclear radiation.

In this study, a low-cost local device based on an Unmanned Aerial Vehicle (UAV) for real-time environmental radiation monitoring is proposed. The device consists of a Geiger-Müller ZP 1200 counter for gamma radiation detection and an appropriate electronic circuit for processing and shaping the detected pulses. The Geiger-Müller detector used is low-cost, insensitive to environmental temperature variations, and can be operated continuously over a long period. Two different methods were performed to calibrate the designed device, namely the use of a programmable nuclear pulse generator for electronic calibration and a Cs-137 gamma-ray calibration source. A long flight time UAV is developed locally with suitable characteristics and adapted to carry the radiation detection device. The designed UAV mainly consists of a multi-flight controller having an intelligent switching system associated with a GPS Module for accurate position-keeping and four heavy lift motors. The use of UAVs has the advantage that it allows measurements to be taken over large areas, even those that are difficult to access, and avoids exposing people to radiation. The flight measurement tests were carried out in the urban area of Yaoundé-Cameroon, at an altitude of 15 to 100 meters with a sweeping speed of about 20 km/h for 36 days from January 01, 2023, to February 06, 2023. The tests showed that the concentrations collected varied between 0.00697 μSv/h and 0.8706 μSv/h, of which 85.71% of data have a concentration below the threshold (0.3 μSv/h) and 14.29% above this threshold. These tests confirm that the developed radiation detection system works properly and is suitable for environmental radiation protection and nuclear safety activities.

Background and Aim: Human is always exposed to natural background ionizing radiation which may have harmful effects; therefore, measurement of the natural background radiation is important. In this study, was measured the dose of effective natural background gamma radiation in indoor residential zones of Hamadan Province. Material and Methods: In this cross-sectional study, we selected four stations along the main geographic directions and one in the center of city for measurement of the indoor dose rate in each of the cities in Hamadan Province. Based on the household numbers, some houses were selected randomly in every station and natural background indoor dose was measured by using RDS-110 survey meter. Then, using the results of our previous study about measuring the level of outdoor natural gamma radiation in this province, we determined the level of annual effective exposure dose from natural gamma radiation in Hamadan residents. Results: In Hamadan province cities, maximum and minimum indoor natural background radiation (gamma ray) belonged to Razan City (1.41±0.079 mSv) and Asadabad City (0.955±0.044 mSv), respectively. Mean annual equivalent indoor dose in Hamadan Province was 1.20±0.070 mSv. Also the maximum indoor natural background radiation dose (gamma ray) in the buildings with the age of more and less than 25 years were 1.42±0.219 mSv and 1.44±0.149 mSv, respectively. According to the results of this study and our previous study about outdoor gamma natural background radiation, the annual effective dose in Hamadan Province residents was 0.83 mSv. Conclusion: According to the results of this study, it seems that annual effective equivalent dose due to indoor gamma radiation in Hamadan Province exceeded the mean external exposure amount reported by UNSCEAR (0.5 mSv). Also the annual effective dose due to gamma background radiation in Hamadan Province residents is 0.83 mSv, which is higher than the global average (0.48 mSv) reported by UNSCEAR - 2000. Therefore epidemiological studies to assess the prevalence of chronic diseases associated with natural radiation exposure among Hamadan Province residents are recommended.

Metal-organic frameworks (MOFs) display a wide range of luminescent behaviors resulting from the multifaceted nature of their structure. In this critical review we discuss the origins of MOF luminosity, which include the linker, the coordinated metal ions, antenna effects, excimer and exciplex formation, and guest molecules. The literature describing these effects is comprehensively surveyed, including a categorization of each report according to the type of luminescence observed. Finally, we discuss potential applications of luminescent MOFs. This review will be of interest to researchers and synthetic chemists attempting to design luminescent MOFs, and those engaged in the extension of MOFs to applications such as chemical, biological, and radiation detection, medical imaging, and electro-optical devices (141 references).

The photon induced current changes in a DC laser produced by optical feedback from an external cavity are shown to be a convenient means of monitoring interference in the laser interferometer. Experiments are carried out using a helium-neon laser operated at 0.6328 and 3.39 mu m wavelengths with variation in path length of the external cavity produced by piezoelectric movement of the external mirror. The frequency response of the voltage fringes appearing across the laser tube is shown to be somewhat less than that of the conventional optical fringes; however in the present case fringing frequencies of 500 kHz were readily observed. Closer investigation using very narrow optical fringes showed that the frequency response of the voltage fringes was determined by their 4 mu s decay time. This technique could be a great asset to laser interferometry in the infrared where radiation detectors are expensive and of low sensitivity.

The increasing utilization of radiological technologies in healthcare, particularly within hospital facilities, continues to advance medical services. However, uncontrolled exposure to ionizing radiation in environments surrounding these facilities poses significant health risks to staff, patients, and the general public. While regulations for radiation safety are established, the implementation and monitoring of radiation levels in the external environments of radiological facilities in developing cities like Pematangsiantar remain underexplored areas. Global trends indicate a rise in secondary radiation exposure incidents requiring attention, yet specific data on the conditions in Pematangsiantar are notably scarce, creating a critical knowledge gap in local radiation risk mitigation and prevention strategies. This study aimed to comprehensively map environmental radiation (gamma) levels at various strategic points around the radiological facilities of three major hospitals in Pematangsiantar and to identify contributing factors to radiation level variations, referencing international radiation safety standards. The primary hypothesis predicted significant variations in environmental radiation levels around radiological facilities, with distance from the radiation source and the presence of shielding materials being key predictors of measured radiation levels. The research employed a descriptive analytical design with a quantitative approach. The sample comprised gamma radiation measurements taken at 100 systematically distributed points within a 50-meter radius of the radiology units in three selected hospitals, utilizing purposive sampling to ensure representation of affected areas. Measurements were conducted using portable Geiger-Müller counters, which were calibrated, demonstrated high accuracy (±5%), and had proven reliability in diverse field conditions. Collected data were analyzed using descriptive statistics to illustrate radiation level distribution and inferential statistics (ANOVA and linear regression) to identify correlations between radiation levels and distance and environmental characteristics. Findings revealed average environmental gamma radiation levels ranging from 0.08 to 0.25 µSv/hour across the three hospitals. Statistically significant differences (p < 0.01) were observed in average radiation levels between hospitals, with Hospital X exhibiting the highest values. Linear regression analysis confirmed distance from the radiation source as the strongest predictor of environmental radiation levels (R² = 0.65, p < 0.001), with radiation levels decreasing exponentially with increasing distance. Notably, unexpected increases in radiation levels were detected at some points near parking areas, suggesting potential secondary exposure from inadequately shielded equipment or minimal accumulated radiation leakage. In conclusion, this study successfully mapped environmental radiation levels around hospital radiological facilities in Pematangsiantar, confirming variations influenced by distance and other environmental factors. These findings contribute to the scientific understanding of external radiation distribution and provide an empirical basis for developing more effective local radiation safety policies. Key recommendations include enhanced routine monitoring, re-evaluation of radiation shielding designs, and ongoing educational programs for the surrounding community regarding potential risks and preventive measures.

Radiation measurements are critical in radioanalytical, nuclear chemistry, and biomedical physics. Continuous advancement in developing economical, sensitive, and compact devices designed to detect and measure radiation has increased its capability in many applications. In this work, we presented and investigated the performance of a cost-effective X-ray radiation detector based on the extended gate field effect transistors (EGFET). We examined the sensitivity of Al-doped Zinc oxide (AZO) of varying thicknesses, fabricated by chemical bath deposition (CBD), following X-ray irradiation with low and high doses. EGFETs were used to connect samples for their detection capabilities. As a function of the absorbed dose, the response was analyzed based on the threshold voltage shift, and the sensitivity of each device was also evaluated. We demonstrated that thin films are less sensitive to radiation than their disk-type EG devices. However, performance aspects of the devices, such as radiation exposure sensitivity and active dosage region, were found to be significantly reliant on the composition and thickness of the materials used. These structures may be a cost-effective alternative for real-time, room-temperature radiation detectors.

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.