Detection

Journal Information
ISSN / EISSN : 2331-2076 / 2331-2084
Published by: Scientific Research Publishing, Inc. (10.4236)
Total articles ≅ 33
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Weiwei Huang, Yanan Hu, Jinjun Zhu, ZeNan Cen, Jiali Bao
Published: 1 January 2022
Journal: Detection
Detection, Volume 09, pp 1-11; https://doi.org/10.4236/detection.2022.91001

Abstract:
In order to evaluate the electromagnetic environment of 5G base station, measurement and evaluation of the electromagnetic environment are studied. The 12 measuring points are chosen on the roof, inside and outside of the building, which has a 5G base station on the top. The electric field intensity, magnetic field intensity, and power density have been measured. The measurement methods include background measurement and work measurement. Background measurement is the measurement of environmental electromagnetic field (EMF) before the installation of 5G base station while the working measurement is the measurement after the installation of 5G base station. The evaluation methods include t-test for qualitative evaluation and electromagnetic gain for quantitative evaluation. The results show that the electromagnetic environment after the installation of 5G base station in most places is different from that in the background. And the environmental electromagnetic fields in certain parts are lower than those in the background. The conclusions are as follows: 1) The electromagnetic environment of 5G base station is far lower than the control limit of the national standard and conforms to the national standard; 2) The electromagnetic environment of 5G base station has little impact on the electromagnetic environment; 3) It is not sufficient to assume that 5G is harmful to health without the results of the epidemiological investigation; 4) Before the construction of 5G base station, do background EMF detection, which can provide support for future evaluation.
Rafika Mejri, Taoufik Aguili
Published: 1 January 2022
Journal: Detection
Detection, Volume 09, pp 29-36; https://doi.org/10.4236/detection.2022.93003

Abstract:
We are interested in this work to electromagnetic leakage, for example the door of the microwave oven (or shielding of electronic functions working in the microwave band containing holes for ventilation circuit) which must be transparent (chain link) but the level of electromagnetic leakage issued by this device must not exceed certain standards. This work started with this article in which we are interested in a simple structure consisting of a multilayer structure incorporating a radiating aperture. We show in this paper mainly the interests of this study and the limitations of using these structures. Modeling of this device is provided by the wave concept iterative procedure (WCIP) which is simple to implement and is characterized by the fast execution method. The validation of our work is carried out by comparing our results with those calculated by the Ansoft HFSS software which shows a good agreement.
Cuixian Zhang
Published: 1 January 2022
Journal: Detection
Detection, Volume 09, pp 13-27; https://doi.org/10.4236/detection.2022.92002

Abstract:
Just as lead-based perovskites that are hot in solar cell preparation, Bi-based perovskites have demonstrated excellent performance in direct X-ray detection, especially the Cs3Bi2I9 single crystals (SCs). However, compared with lead-halide perovskites, one challenge for the Cs3Bi2I9 SCs for X-ray detection application is that it is difficult to prepare large-sized and high-quality SCs. Therefore, how to get a large area with a high-quality wafer is also as important as Cs3Bi2I9 growth method research. Here, different anti-solvents are used for the preparation of poly-crystalline powder with the Antisolvents precipitation (A) method, as a control, High-energy ball milling (B) was also used to prepare poly-crystalline powders. The resultant two types of Cs3Bi2I9 wafer exhibit a micro-strain of 1.21 × 10-3, a resistivity of 5.13 × 108 Ω cm and a microstrain of 1.21 × 10-3, a resistivity of 2.21 × 109 Ω cm. As a result, an X-ray detector based on the high-quality Cs3Bi2I9 wafer exhibits excellent dose rate linearity, a sensitivity of 588 μC·Gyairs-1·cm-2 and a limit of detection (LoD) of 76 nGyair·s-1.
Dabo S. I. Agba, Koudou Djagouri, Bogbe D. L. H. Gogon, Aka A. Koua
Published: 1 January 2021
Journal: Detection
Detection, Volume 08, pp 1-8; https://doi.org/10.4236/detection.2021.81001

Abstract:
In this study, we used strippable LR 115 type 2 which is a Solid State Nuclear Track Detector (SSNTD) widely known for radon gas detection and measurement. The removed thickness of the active layer of samples of this SSNTD, were determined by measuring the average initial thickness (before etching) and residual thickness after 80 to 135 minutes chemical etching in the standard conditions, using an electronic comparator. These results allowed the calculation of the bulk etch rate of this detector in a simple way. The mean value obtained is (3.21 ± 0.21) μm/h. This value is in close agreement with those reported by different authors. It is an important parameter for alpha track counting on the sensitive surface of this polymeric detector after chemical etching because track density depends extremely on its removed layer. This SSNTD was then used for environmental radon gas monitoring in Côte d’Ivoire.
Jamiu Idowu Lawal
Published: 1 January 2019
Journal: Detection
Detection, Volume 07, pp 1-15; https://doi.org/10.4236/detection.2019.71001

Abstract:
Natural radionuclides content in granite from eight functional quarries in Osun State, Southwestern Nigeria was assessed. Eighty granite samples comprise ¾ inches. ½ inch and stone-dust were collected from Wolid, Slava, Ayofe, Espro, Ife/Modakeke, Krystal Vountein, Clario and Omidiran quarries in the State. Measurement was done using a high purity germanium (HPGe) detector. The statistical analysis was carried out using Statistical Package for Social Sciences (SPSS) software to determine if granite size has an impact on the activity concentrations. The results revealed that the mean activity concentrations of 238U (12.64 ± 1.89 Bq·kg -1) and 232Th (16.93 ± 2.46 Bq·kg -1) were highest in ¾ inch granite and lowest in stone-dust (5.01 ± 0.77 and 8.97 ± 1.37 Bq·kg -1 respectively), whereas 40K is highest in the ¾ inches (266.19 ± 35.53 Bq·kg -1) and lowest in ½ inches (151.85 ± 25.09 Bq·kg -1) granite. Espro has the highest (23.75 ± 3.74 Bq·kg -1) while Wolid has the lowest (4.11 ± 0.73 Bq·kg -1) 238U activity concentration and Slava has lowest for 232Th (8.21 ± 1.12 Bq·kg -1) and 40K (109.54 ± 11.06 Bq·kg -1). The radiological hazard parameters such as absorbed dose, annual effective dose radium equivalent, gamma index, external index, and internal index, were calculated to assess the radiation hazards associated with granite samples. The results obtained are lower than the recommended limits. The results were compared with the published data of other countries. Although, all the calculated radiation hazard indices were lower than the permissible limits. Therefore, people working in the quarries, granite end-users and the general public are safe from radiological health risks from the quarries, since there is no significant health hazard. The research will give reliable information on activity concentrations of natural radionuclides in granite rocks, contribute to a better understanding of radioactivity distribution in granite, and develop standards.
Xinghua Shi, Quang Phan, , Lance L. McDowell, Jijun Qiu, Zhihua Cai,
Published: 1 January 2018
Journal: Detection
Detection, Volume 06, pp 1-16; https://doi.org/10.4236/detection.2018.61001

Abstract:
This paper provides a theoretical study and calculation of the specific detectivity-D* limit of photovoltaic (PV) mid-wave infrared (MWIR) PbSe n+-p junction detectors operating at both room temperature and TE-cooled temperature. For a typical PbSe p-type doping concentration of 2 × 1017 cm-3 and with high quantum efficiency, the D* limits of a photovoltaic PbSe n+-p junction detector are shown to be 2.8 × 1010 HZ1/2/W and 3.7 × 1010 HZ1/2/W at 300 K and 240 K, with cut-off wavelength of 4.5 μm and 5.0 μm, respectively. It is almost one magnitude higher than the current practical MWIR PV detector. Above 244 K, the detector is Johnson noise limited, and below 191 K the detector reaches background limited infrared photodetector (BLIP) D*. With optimization of carrier concentration, D* and BLIP temperature could be further increased.
Laith Ahmed Najam, Abdalsattar Kareem Hashim, Hussein Abdulkareem Ahmed, Israa M. Hassan
Published: 1 January 2016
Journal: Detection
Detection, Volume 04, pp 33-39; https://doi.org/10.4236/detection.2016.42005

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