Search Results (8)

In this study, we demonstrated the process of an integrated apparatus for decay time analysis and gamma radiation measurement with a liquid-scintillator-based cadmium-doped zinc oxide (CZO) nanomaterial. Generally, time-resolved photon counting is an essential analysis method in the field of precision measurement in the quantum domain. Such photon counting equipment requires a pulse laser that can be repeated quickly while having a sharp pulse width of picoseconds or femtoseconds as a light source. Time-correlated single photon counting (TCSPC) equipment, which is currently a commercial product, is inconvenient for recent development research because the scintillator size and shape are limited. Here, neodymium-doped yttrium aluminum garnet (Nd/YAG) laser TCSPC equipment was constructed to analyze the fluorescence characteristics of scintillators having various sizes and shapes. Then, a liquid scintillator added with CZO nanomaterial was prepared and the Nd/YAG laser TCSPC equipment test was performed. As a result of measuring the scintillator using the manufactured Nd/YAG laser TCSPC equipment, the non-CZO liquid scintillator was analyzed at 2.30 ns and the liquid scintillator equipped with CZO-loaded nanomaterial was analyzed at 11.95 ns. It showed an error within 5% when compared with the result of commercial TCSPC equipment. In addition, it was verified that the Nd/YAG laser TCSPC system can sufficiently measure the decay time in nanoseconds (ns). Moreover, it was presented that the Compton edge energy of Cs−137 is 477.3 keV, which hardly generates a photoelectric effect, and Compton scattering mainly occurs. Full article

The miniaturization and usability of radiation detectors make it increasingly possible to use mobile instruments to detect and monitor gamma radiations. Here, a Bluetooth-based mobile detection system for integrated interaction in a backpack was designed and implemented to smart equipment for the detection of radioactive cesium on contaminated soil. The radiation measurement system was demonstrated in the form of a backpack using a quantum dot (QD)-loaded plastic scintillator manufactured and prepared directly in this study, and it can be measured by a person in the wireless framework of integrated interaction. The QD-loaded plastic scintillator was measured after setting the distance from the contaminated soil to 20, 50, and 100 mm. As a result, the detection efficiency of the commercial plastic scintillator (EJ-200) was calculated to be 11.81% and that of the QD-loaded plastic scintillator was 15.22%, which proved the higher detection efficiency performance than the commercial plastic scintillator. The measurement result was transmitted to a personal computer using Bluetooth as a portable system. In the future, this wireless system design could be expanded as a wireless communication system equipped with a global positioning system to detect and measure radioactively contaminated environments. Full article

Recently, nanomaterial-based scintillators are newly emerging technologies for many research fields, including medical imaging, nuclear security, nuclear decommissioning, and astronomical applications, among others. To date, scintillators have played pivotal roles in the development of modern science and technology. Among them, plastic scintillators have a low atomic number and are mainly used for beta-ray measurements owing to their low density, but these types of scintillators can be manufactured not in large sizes but also in various forms with distinct properties and characteristics. However, the plastic scintillator is mainly composed of C, H, O and N, implying that the probability of a photoelectric effect is low. In a gamma-ray nuclide analysis, they are used for time-related measurements given their short luminescence decay times. Generally, inorganic scintillators have relatively good scintillation efficiency rates and resolutions. And there are thus widely used in gamma-ray spectroscopy. Therefore, developing a plastic scintillator with performance capabilities similar to those of an inorganic scintillator would mean that it could be used for detection and monitoring at radiological sites. Many studies have reported improved performance outcomes of plastic scintillators based on nanomaterials, exhibiting high-performance plastic scintillators or flexible film scintillators using graphene, perovskite, and 2D materials. Furthermore, numerous fabrication methods that improve the performance through the doping of nanomaterials on the surface have been introduced. Herein, we provide an in-depth review of the findings pertaining to nanomaterial-based scintillators to gain a better understanding of radiological detection technological applications. Full article

Plastic scintillators are widely used in various radiation measurement applications, and the use of plastic scintillators for nuclear applications including decommissioning, such as gamma-ray detection and measurement, is an important concern. With regard to efficient and effective gamma-ray detection, the optimization for thickness of plastic scintillator is strongly needed. Here, we elucidate optimization of the thickness of high-performance plastic scintillator using high atomic number material. Moreover, the EJ-200 of commercial plastic scintillators with the same thickness was compared. Two computational simulation codes (MCNP, GEANT4) were used for thickness optimization and were compared with experimental results to verify data obtained by computational simulation. From the obtained results, it was confirmed that the difference in total counts was less than 10% in the thickness of the scintillator of 50 mm or more, which means optimized thickness for high efficiency gamma-ray detection such as radioactive ¹³⁷Cs and ⁶⁰CO. Finally, simulated results, along with experimental data, were discussed in this study. The results of this study can be used as basic data for optimizing the thickness of plastic scintillators using high atomic number elements for radiation detection and monitoring. Full article

Herein, we review studies of the integration of Phoswich detectors with readout integrated circuits and the associated performance in a radiological sensing application. The basic concept and knowledge of interactions with scintillation materials and the mechanisms and characteristics of radiological detection are extensively discussed. Additionally, we summarize integrated multiple detection systems and Phoswich detectors in radiological measurements for their device performance. Moreover, we further exhibit recent progress and perspective in the future of Phoswich-based radiological detection and measurement. Finally, we provide perspectives to evaluate the detector performance for radiological detection and measurement. We expect this review can pave the way to understanding the recent status and future challenges for Phoswich detectors for radiological detection and measurement. Full article

The highly reliable and direct detection of radioactive cesium has gained potential interest due to in-situ detection and monitoring in environments. In this study, we elucidated an integrated and portable probe based on functional plastic scintillator for detection of radioactive cesium. A functional plastic scintillator with improved detection efficiency was fabricated including CdTe (cadmium telluride) material. Monolith-typed functional plastic scintillator having a diameter of 50 mm and a thickness of 30 mm was manufactured by adding 2,5-diphenyloxazole (PPO, 0.4 wt%), 1,4 di[2-(5phenyloxazolyl)]benzene (POPOP, 0.01 wt%), and CdTe (0.2 wt%) materials in a styrene-based matrix. To evaluate the applicability of the plastic scintillator manufactured to in-situ radiological measurement, an integrated plastic detection system was created, and the measurement experiment was performed using the Cs-137 radiation source. Additionally, detection efficiency was compared with a commercial plastic scintillator. As results, the efficiency and light yield of a functional plastic scintillator including CdTe were higher than a commercial plastic scintillator. Furthermore, the remarkable performance of the functional plastic scintillator was confirmed through comparative analysis with Monte Carlo simulation. Full article

Functional plastic scintillators have attracted much attention for their usefulness in on-site monitoring and detection in environments. In this study, we elucidated a highly reliable and functional plastic scintillator for detection of radioactive strontium, which means a potent perovskite-loaded polymeric scintillation material based on epoxy and 2,5-diphenyloxazole (PPO). Moreover, Monte Carlo N-Particle (MCNP) simulation was performed to optimize the thickness of a plastic scintillator for efficient strontium detection. A thickness of 2 mm was found to be the optimum thickness for strontium beta-ray detection. A newly developed plastic scintillator with 430 nm emission from perovskite loading could trigger scintillation enhancement employing potential indication of perovskite energy transfer into a photomultiplier (PMT) detector. Furthermore, the response to beta-ray emitter of ⁹⁰Sr was compared to commercial scintillator of BC-400 by exhibiting detection efficiency in the energy spectrum with a fabricated perovskite-loaded plastic scintillator. We believe that this suggested functional plastic scintillator could be employed as a radiation detector for strontium detection in a wide range of applications including decommissioning sites in nuclear facilities, nuclear security and monitoring, nonproliferation, and safeguards. Full article

The detection and monitoring systems of low energy beta particles are of important concern in nuclear facilities and decommissioning sites. Generally, low-energy beta-rays have been measured in systems such as liquid scintillation counters and gas proportional counters but time is required for pretreatment and sampling, and ultimately it is difficult to obtain a representation of the observables. The risk of external exposure for low energy beta-ray emitting radioisotopes has not been significantly considered due to the low transmittance of the isotopes, whereas radiation protection against internal exposure is necessary because it can cause radiation hazard to into the body through ingestion and inhalation. In this review, research to produce various types of detectors and to measure low-energy beta-rays by using or manufacturing plastic scintillators such as commercial plastic and optic fiber is discussed. Furthermore, the state-of-the-art beta particle detectors using plastic scintillators and other types of beta-ray counters were elucidated with regard to characteristics of low energy beta-ray emitting radioisotopes. Recent rapid advances in organic matter and nanotechnology have brought attention to scintillators combining plastics and nanomaterials for all types of radiation detection. Herein, we provide an in-depth review on low energy beta emitter measurement. Full article