Portable Radiation Detector Research Articles

소모전력 감소를 위한 단일 전원 휴대용 방사선 검출장치 구현

Safety and security system have been internationally enhanced in a field of shipping logistics. Accordingly, techniques for safety and security have been studied steadily. The need of portable radiation detection device is increasing by the search of the container is enhanced. In this paper, we propose a study to improve the life of the system and the realization of portable radiation detection device based on Cortex-A9. Configuration of a portable radiation detection device is configured largely to an analog board and the digital platform and the sensor module. The power used in each stage of the analog board is varied. Uses a switching regulator to use various power supply thereby to generate an error result and cause the switching noise. It is proposed to reduce the power consumption reducing technique for the study.

Cortex-A9 기반 휴대용 방사선 검출장치에서의 검출성능 향상을 위한 연구

Cortex-A9 기반 휴대용 방사선 검출장치에서의 검출성능 향상을 위한 연구

In situ clouds-powered 3-D radiation detection and localization using novel color-depth-radiation (CDR) mapping

The article presents an in situ clouds-powered radioactive source detection and localization approach, namely color-depth-radiation mapping, using 3-D land mapping within hazardous indoor environment and incorporating sensor fusion between a RGB-D camera and a portable radiation detector. In the approach, to achieve fast and robust image registration, color images detected by the camera are initially employed to extract crucial visual features and establish pairs of matched image features between successive scanned images. Following this, matched features are incorporated with the corresponding calibrated depth information to generate 3-D keypoint cloud pairs. To remove potential noises in the acquired data-sets, a novel geometric-based filtering algorithm is developed to reject incorrect keypoint pairs prior to iterative closest point-based image registration. Most importantly, an algorithm to determine the radioactive sources’ parameters including strength and 3-D position is developed for accurate radioactive source detection and localization. With this, the radioactive sources can be accurately pinpointed in the established 3-D map for efficient contamination control and safety management. Two radiation testing experiments were performed to verify the feasibility of the approach and its detection accuracy. The simulation results indicate that the proposed approach can reach up to 95% accuracy of radiation source localization incorporated in the 3-D map.

Cortex-A9 기반 휴대용 방사선 검출장치에서의 온도보상 알고리즘 구현

Safety and security system have been internationally enhanced in a field of shipping logistics. Accordingly, techniques for safety and security have been studied steadily. The need of portable radiation detection device is increasing by the search of the container is enhanced. In this paper, we propose to study on the application of the temperature compensation algorithm to the platform to improve the accuracy and the realization of portable radiation detection device based on Cortex-A9. Analog board deforms signal output from the sensor. And Cortex-A9 platform analyzes the signal received and displays the results. Additionally we use the temperature compensation algorithm and thereby we ca look the same results even if the temperature changes.

Cortex-A8을 이용한 휴대용 감마선 검출 플랫폼 구현

As safety and security systems of shipping logistics are reinforced all over the world, ubiquitous technology-based core technology for safety and security is developing to build the system of logistics security. It is feared that the logistics security system of Korea has a possibility to technically depend on developed countries in the futures. Because the essential skills and equipment to retain security of logistics are not developed. It is urgent to introduce a logistics security system that fully integrates the entire logistics segment in the future. Thus, the necessity of developing the portable radiation detector which can detect gamma-ray nuclide is increasing for reinforcing safety and security systems. In this paper, a research suggests the implementation of portable radiation detector platform using Cortex-A8.

NaI(Tl) Scintillator를 이용한 휴대용 방사선 검출 장치 구현에 대한 연구

전 세계적으로 해운물류 안전 보안체계가 강화됨에 따라 국가물류보안 체계 구축을 위한 유비쿼터스 기술 기반의 해운물류 안전 보안 핵심기술 개발이 이루어지고 있다. 현재까지의 U-기반 해운물류 안전보안 시스템 개발과 관련하여 X-선을 이용한 3차원 검색장치 즉, 화물검색장치 개발에 대한 핵심기술을 개발해 오고 있고, 추가적으로 감마선을 검출할 수 있는 휴대용 방사선 검출 장치의 개발 필요성이 높아지고 있다. 본 논문에서는 방사선에 의한 인체, 물체 및 공공상의 장해를 미연에 방지하기 위한 고속의 휴대용 방사선 검출 장치 플랫폼 구현에 대한 연구를 제안하고자 한다. Over the world, the development of critical technology for the safety and security of coastal distribution based on ubiquitous computing is being processed to meet the bottom lines of governmental regulations. Currently, 3D detectors using X-rays for freight search technology are being developed concerning U-based shipping security systems. In addition to that, there are increasing needs for developing portable radiation detector to detect gamma rays. The purpose of the thesis is to suggest the research of high speed portable gamma rays detector platform to prevent disorder caused to humans and public objects.

A new FSA approach for in situ γ ray spectroscopy

An increasing demand of environmental radioactivity monitoring comes both from the scientific community and from the society. This requires accurate, reliable and fast response preferably from portable radiation detectors. Thanks to recent improvements in the technology, γ spectroscopy with sodium iodide scintillators has been proved to be an excellent tool for in-situ measurements for the identification and quantitative determination of γ ray emitting radioisotopes, reducing time and costs. Both for geological and civil purposes not only 40K, 238U, and 232Th have to be measured, but there is also a growing interest to determine the abundances of anthropic elements, like 137Cs and 131I, which are used to monitor the effect of nuclear accidents or other human activities.The Full Spectrum Analysis (FSA) approach has been chosen to analyze the γ spectra. The Non Negative Least Square (NNLS) and the energy calibration adjustment have been implemented in this method for the first time in order to correct the intrinsic problem related with the χ2 minimization which could lead to artifacts and non physical results in the analysis.A new calibration procedure has been developed for the FSA method by using in situ γ spectra instead of calibration pad spectra. Finally, the new method has been validated by acquiring γ spectra with a 10.16cm×10.16cm sodium iodide detector in 80 different sites in the Ombrone basin, in Tuscany. The results from the FSA method have been compared with the laboratory measurements by using HPGe detectors on soil samples collected particular, the 137Cs isotopes has been implemented in the analysis since it has been found not negligible during the in-situ measurements.

Ultra-low Power CMOS Front-End Readout ASIC for Portable Digital Radiation Detector

An ultra-low power complementary metal-oxide-semiconductor (CMOS) front-end readout ASIC was developed for a portable digital radiation detector. The ASIC having a charge sensitive amplifier and a semi-Gaussian pulse-shaper was produced using the CSMC 0.5 μm DPDM process. The ENC noise of 363 e at 0 pF with a noise slope of 23 e/pF complies with the stringent low noise requirements. The peaking time was 250 ns at a 100 mV/fC conversion gain (detector capacitance is 20 pF). By operating this front-end readout ASIC in the weak inversion region, the ultra-low power dissipation is only 0.1 mW/channel (3.0 V). Simulations and test results suggest that this design gives lower power consumption than the front-end readout ASICs working in the strong inversion and is appropriate for the portable digital radiation detectors.

Continuous Monitoring of Left Ventricle Function by VEST in Hemodialyzed Patients

Cardiovascular disease is a major cause of morbidity and mortality in chronic kidney disease. Radionuclide-based methods can be used for analyses on the perfusion of coronary arteries and ventricular function. The present study reports the use of a new procedure for continuous measurements of left ventricle function during a dialytic session with the use of a recently developed portable gamma radiation detector (ventricular function study system). On average, left ventricle ejection fraction and stroke volume progressively and continuously decreased throughout the session (end session versus baseline: -13.8% for ejection fraction, -25.9% for stroke volume, P<.02). A biphasic response was found for heart rate: a transient modest decrease (at session midpoint, -4.2%) followed by an increase up to values higher than baseline (end session, +4.7%). Cardiac output decreased by 10.4% at session midpoint (P=.023 versus baseline) without further reduction in the following hours. Mean changes in systolic pressure paralleled data for cardiac output. Individual changes in indices of left ventricle function were scattered and strongly were correlated with thickness of interventricular septum and telediastolic left ventricular volume measured by standard echocardiogram in the interdialytic period (R>.75, P<.05). Data indicate that the ventricular function study system could be a powerful tool for characterization of the profile of left ventricular function in hemodialyzed patients.

Radiation exposure around patients after administration of 123I-MIBG

Estimation of the radiation exposure to neighbouring patients, personnel and relatives deriving from patients undergoing 123I-MIBG scintigraphy. For scintigraphic studies, 16 patients with suspected pheocromocytoma were injected with 340 +/- 30 MBq 123I-MIBG. Dose rates were measured at a distance of 0.5 m, 1 m, and 2 m after 10 min, 3 h, 21 h, 45 h, and 68 h using three calibrated portable radiation detectors. The emasured values were background corrected. Ten minutes after injection the dose rate was 10.5 microS/h at a distance of 0.5 m, 3.78 microS/h at 1 m, and 0.95 microS/h at 2 m. The effective half-life was estimated to 8.68 +/- 0.15 h. The maximum dose in a distance of 1 m for neighbouring patients was 46 microS/h, for personnel in a ward 27 microS/h, and to relatives in a distance of 2 m 12 microS/h. This study demonstrates that the calculated exposure to people around patients after 123I-MIBG injection is well below the maximum permissible annual dose limit of 1 mSv for not professionally exposed persons.

Elements of a portable radiation detector calibration program.

The Department of Environmental Health & Safety at San Diego State University (SDSU) calibrates portable radiation detectors as a service to the university's research community. SDSU's calibration program was developed and implemented based on selected recommendations provided by the American National Standards Institute and the National Council on Radiation Protection and Measurements. This paper outlines the elements of the calibration program including, technical references and the rationale for program development. Covered under the provisions of this paper include those instruments used to evaluate the dose rates from radioactive materials and those instruments used to determine radioactive contamination or uptake. Those detectors specifically not addressed are liquid scintillation counters, semi-conductors, neutron dose rate instruments, and instruments intended for quantifying dose rates due to beta emission.

放射線防護用機器 ＸＶＩＩＩ． 放射線管理計測技術の最近の進歩 ３． ポータブル放射線測定器の最近の進歩

放射線防護用機器 ＸＶＩＩＩ． 放射線管理計測技術の最近の進歩 ３． ポータブル放射線測定器の最近の進歩

A Survey of Radon‐222 in Ground Water from the Sherwood Sandstone Aquifer: Belfast and Newtownards, Northern Ireland

AbstractA study of radon‐222 in ground water in Northern Ireland has revealed a range of concentrations from 5.8Bql−1 to 36.6Bql−1 (158pCil−1 (158pCil−1 to 989 pCil−1). Radon‐222 was measured using a portable degassing system with scintillation cells and a portable radiation detector. Twenty‐six samples were taken within the Sherwood Sandstone Aquifer underlying Belfast and Newtownards, County Down.; All samples collected were below the National Radiological Protection Board (NRPB) suggested limit of 100Bql−1. Several hypotheses were considered for the distribution pattern in the sandstone, the most probable being the presence of faults and lithological differences.

A Method for Estimating &lt;sup&gt;137&lt;/sup&gt;Cs Body Burden Under Emergency Conditions

The Goiania accident involving 137Cs resulted in the internal contamination of 129 persons, of ages between 1 and 60 years, up to levels of approximately 250 MBq. The relationship is described between the dose rate at the body surface as measured by portable radiation detectors and the 137Cs body burden as measured by whole-body counting techniques for 3 adolescents and 8 adults involved in the accident. This relationship can be used in the case of similar accidents to estimate quickly 137Cs body burdens. The dose rate measurements at the axillas give the most representative results for estimating the 137Cs body burden.

Lung vascular permeability in patients with acute pancreatitis.

Acute pancreatitis may be complicated by acute lung injury associated with increased lung vascular permeability to plasma protein. The pulmonary accumulation of the plasma protein transferrin, radiolabelled in vivo with indium-113m, was monitored using a portable probe radiation detector in sixteen patients with acute pancreatitis. Plasma protein accumulation (PPA) indices were within normal limits (less than 0.5 X 10(-3)min-1) in all survivors (n = 10) and elevated in all but one of the non-survivors. All non-survivors had severe acute pancreatitis as judged by standard criteria. Thus increased lung vascular permeability was not a constant feature of uncomplicated acute pancreatitis and was only observed in patients with multisystem failure accompanied by clinically evident acute lung injury.

An improved technique of intra-operative bone scanning.

Radiopharmaceuticals have been successfully used to detect occult neoplasms and infective lesions. Bone scans using 99mTc-labelled methylene diphosphonate located osteoid osteomas accurately in a series of 30 symptomatic patients. A portable radiation detector system has been designed to help intra-operative localisation and facilitate complete excision of the lesions with minimal damage to normal tissue. A sodium iodide detector with a fibre-optic link was used at first, but a cadmium telluride system has provided a more durable, reliable and sensitive sterilisable probe.

Assessment of thromboresistance of intravenous cannulae by 125I-fibrinogen scanning.

Assessment of potentially thromboresistant polymers and other materials has been impeded by the lack of a simple and safe test procedure in man. This report describes the use of a portable gamma radiation detector to assess accumulation of 125I-fibrinogen in thrombi related to intravenous cannulae. The method was first employed in 19 dogs and one sheep with FEP-Teflon forelimb intravenous cannulae which were scanned for up to 6 h after insertion. Results were compared with findings at post mortem examination. Eleven thrombi developed, nine of which emitted more than 3500 counts per minute; eight of these (89%) were detected by external scanning. The smallest thrombus detected weighed 0.7 mg. The method did not distinguish between thrombus and hematoma. Fifty FEP-Teflon cannulae were then studied in 39 patients after injection of 100 microCi 125I-fibrinogen. Cannulae and control sites were scanned twice daily and an independent blind clinical appraisal was performed by an experienced nurse. A rise in percentage uptake (count at a limb site/heart count X 100) of 20 or a difference of 40 between adjacent sites was regarded as a positive test. Scans became positive up to 30 h before clinical evidence of phlebitis was observed. The interval between insertion and thrombosis of both large and small cannulae detected by scanning was significantly shorter than that determined by clinical assessment (p less than 0.001). Physical signs of phlebitis were noted with 58% of large cannulae (16 or 18 gauge)and 33% of small cannulae (22 gauge) at the time of removal. Positive 125I-fibrinogen tests were obtained with 70% of large cannulae and 75% of small cannulae. 125I-fibrinogen scanning is a safe simple sensitive technique to detect thrombosis related to intravenous cannulae. The test should enable comparisons of different cannula materials in man.

A noninvasive technique for monitoring lung vascular permeability in man.

Increased microvascular permeability resulting in increased plasma protein extravasation is the hallmark of acute inflammatory oedema and hence radiolabelled proteins can be used to monitor this process. The adult respiratory distress syndrome (ARDS) is characterized by acute inflammatory oedema and thus provides an ideal model for studying this type of oedema in the human lung. A noninvasive technique applicable to the intensive care unit has been developed for monitoring the pulmonary accumulation of the plasma protein transferrin. Transferrin was radiolabelled in vivo with indium-113m and its accumulation was monitored using a portable probe radiation detector. After correcting for changes in intrathoracic blood distribution, by simultaneously monitoring the accumulation of technetium-99m-labelled red blood cells, an index of plasma protein accumulation was calculated. In all patients with established ARDS (n = 10) the index values were greater than 1.0 X 10(-3) min-1 and these were clearly separate from the values of less than 0.5 X 10(-3) min-1 in all healthy volunteers (n = 5; P less than 0.001). The technique can clearly detect raised plasma protein accumulation indices in the lungs of patients with established inflammatory oedema of ARDS and hence may provide a pharmacological tool for the rapid evaluation in these conditions of the effects of drugs (like corticosteroids) which are known to modulate inflammatory oedema.

A regulated high voltage supply for portable radiation detectors.

A regulated high voltage supply for portable radiation detectors.

Portable radiation detectors employing photoconductive cells

The difficulties inherent in the design of small portable, battery-powered, infra-red detectors employing photoconductive cells are discussed, with particular reference to the signal-to-noise ratio of suitable electronic amplifiers, and the method employed to "chop" the radiation. The main novelty is the use of an electromagnetically-maintained vibrating leaf-spring with a shutter suitably mounted at its free end as a radiation chopper. The design and applications of this device are discussed in some detail.