Surface Contamination Research Articles

Evaluation of Peel Ply Effectiveness in Controlling Mould Release Agent Contamination of Epoxy/Carbon Fibre Composite Laminate Surfaces

The peel-ply effectiveness in controlling the mould release contaminations of resin transfer molded (RTM) RTM6/G0926 epoxy-carbon fibre composite laminate surfaces have been examined. X-ray photoelectron spectroscopy (XPS) was employed to evaluate the extent of transfer of mould release agents and other surface contaminants of RTM composite laminates at semi-cured and fully cured states. Fully cured and 55% semi-cure degree of RTM composite laminates were prepared using polyester and diatex peel plies. The effectiveness of polyester and diatex peel plies were evaluated by comparing the amount of Frekote mould release contaminants present in the laminate surfaces processed with and without peel plies. The XPS results shows that the composite laminates processed without peel plies at different cured states exhibit uniform contamination with Freakote calcium metal ions. At the comparisons of polyester and diatex peel plies, the diatex peel ply performs better in controlling the surface contaminations.

Method to improve the classification accuracy by in situ laser cleaning of painted metal scraps during laser-induced breakdown spectroscopy based sorting

Abstract Scrap metals are typically covered with surface contaminants, such as paint, dust, and rust, which can significantly affect the emission spectrum during laser-induced breakdown spectroscopy (LIBS) based sorting. In this study, the effects of paint layers on metal surfaces during LIBS classification were investigated. LIBS spectra were collected from metal surfaces painted with black and white paints by ablation with a nanosecond pulsed laser (wavelength = 1064 nm, pulse width = 7 ns). For the black-painted samples, the LIBS spectra showed a broad background emission, emission lines unrelated to the target metals, large shot-to-shot variation, and a relatively low signal intensity of the target metal, causing poor classification accuracy even at high shot numbers. Cleaning the black paint layer by ablating over a wide area prior to LIBS analysis resulted in high classification accuracy with fewer shot numbers. A method to determine the number of cleaning shots necessary to obtain high classification accuracy and high throughput is proposed on the basis of the change in LIBS signal intensity during cleaning shots. For the white-painted samples, the paint peeled off the metal surface after the first shot, and strong LIBS signals were measured after the following shot, which were attributed to the nanoparticles generated by the ablation of the paint, allowing an accurate classification after only two shots. The results demonstrate that different approaches must be employed depending on the paint color to achieve high classification accuracy with fewer shot numbers.

Efficacy of Antimicrobial Dry Fog in Improving the Environmental Microbial Burden in an Inpatient Ward

Background/Objectives: In healthcare environments with high microbial loads, effective infection control measures are critical for reducing airborne and surface contamination. One of the novel modalities in the achievement of these goals is the use of antimicrobial mists, such as droplets, in the form of dry fog. Although the usage of dry fog in the disinfection of contained healthcare microenvironments is well known, the effect of such a system in terms of a meaningful reduction in the microbial burden in an open inpatient ward is unclear. Our objective was to assess the impact of scheduled dry fogging on microbial reduction in such settings. Methods: We collected air and surface samples from rooms receiving daily, biweekly, or no fogging (controls) over six months, establishing the baseline contamination and evaluating the reduction trends in treated rooms. The “reduction effect” was measured by tracking microbial isolation trends before and after treatment, while the “degree of reduction” assessed differences across rooms with varied disinfection schedules. Results: The results indicate that scheduled dry fogging significantly reduced microbial loads in treated rooms, especially with daily disinfection (SE = 64.484, p = 0.002). The airborne contamination in treated rooms showed a strong downward trend over time (SE = 19.192, p < 0.001). Surface contamination remained challenging due to frequent recontamination; however, treated rooms exhibited a consistent reduction in microbial presence (SE = 2.002, p = 0.010), confirming dry fogging’s role as a valuable adjunct to routine cleaning. Conclusions: In conclusion, this study highlights that dry fogging effectively reduces microbial loads in open, high-traffic healthcare environments, supporting its use as part of a multimodal infection control strategy.

Comparison of calibration results for α, β surface contamination monitors

Abstract Surface contamination monitors are used intensively in many facilities, like in the nuclear medicine departments for clearance measurements and decontamination and in decommissioning of nuclear installations. For a reliable use, all surface contamination monitors should have a valid calibration with traceability to the international standards. A comparison exercise for calibrations in terms of efficiency in 2π steradian for surface contamination monitors was organized between five dosimetry calibration laboratories, members of EURAMET (The European Association of National Metrology Institutes). Four β-beta radionuclide sources, Sr-90, Cl-36, Cs-137, Co-60, and one α-alpha source, Am-241, were used for calibrations during this exercise. Two transfer surface contamination monitors, one Canberra SABG 100 and one Berthold LB 124 with 100 cm2 and 343 cm2 effective area, respectively, were used. The monitors were circulated between the partners and were periodically returned to the pilot laboratory for stability checks. The efficiencies in 2π steradian measured by the participants do not fully agree for all sources and both detectors despite the fact that all laboratories used similar types of surface contamination sources and had proper traceability to primary standards for surface emission rate measurements. As no evident difference in measurements of surface emission rates is expected between the primary standard laboratories that calibrated the sources, it is very probable that the observed differences are mainly due to the calibration procedures used by each laboratory and that the measurement uncertainties of efficiency in 2π steradian are underestimated. This report presents the results of this pilot comparison for calibration of surface contamination monitors and stresses the need to organize similar generalized exercises. This report also identifies some gaps in procedures for calibration of surface contamination monitors.

The bacterial burden of worn face masks-observational research and literature review.

Facemasks were widely mandated during the recent SARS-CoV-2 pandemic. Especially the use by the general population is associated with a higher risk of improper handling of the mask and contamination and potential adverse microbiological consequences. We investigated and quantified bacterial accumulation in facemasks used by the general population, using 16S rRNA (Sanger Sequencing), culture and biochemical analysis along with Rose Bengal staining. Additionally, a systematic overview of the literature on face mask contamination was undertaken. We found an average bacterial load of 4.24 × 104 CFU recovered/mask, with a maximum load of 2.85 × 105 CFU. This maximum is 310 times higher than the limit value for contamination of ventilation system outlet surfaces specified by the German standard VDI 6022. Biochemical and molecular identification predominantly found Staphylococcus species (80%), including Staphylococcus aureus, along with endospore-forming Bacillus spp. Literature reports also indicate contamination of masks by bacterial and fungal opportunists of the genera Acinetobacter, Aspergillus, Alternaria, Bacillus, Cadosporium, Candida, Escherichia, Enterobacter, Enterococcus, Klebsiella (including K. pneumoniae), Micrococcus, Microsporum, Mucor, Pseudomonas, Staphylococcus and Streptococcus. Bacterial counts increase linearly with wearing duration. Prolonged use may affect the skin and respiratory microbiomes, promoting consequential eye, skin, oral and airway conditions. These aspects underscore the urgent need for further research and a risk-benefit analysis in respect of mask use, particularly given their unproven efficacy in disrupting the transmission of respiratory viruses and their adverse social consequences.

Exposure to specific fungal lectins during adhesion impairs biofilm formation of Listeria on polystyrene.

Listeria monocytogenes is a pathogenic bacterium that can form biofilms in food processing plants, allowing the bacteria to survive despite the control measures applied. As the surface of the bacteria is covered with versatile polysaccharides and proteins, these influence the interactions of the bacterium with any surface. The unique properties and high stability of fungal proteins make them good candidates for the control of bacteria by targeting surface structures. We screened a group of fungal lectins and protease inhibitors from different fungal species, protein folds and known targets for their antibacterial and antibiofilm activity against model strains of Listeria innocua and Listeria monocytogenes. Several of them significantly decreased the viability of biofilm bacteria, but had no effect on bacterial growth parameters at 37°C and thus had no antibacterial activity. Fungal lectins significantly impaired biofilm development even at room temperature, which was attributed to exposure to lectins during adhesion. The tested fungal proteins also reduced biofilm development on biological model surfaces. The observed antibiofilm activity of fungal proteins suggests that they have the potential to modulate interactions between bacteria and/or between bacteria and surfaces, which could be used in the future to reduce surface contamination by Listeria.

Sustainable Protocols For Leaf Sample Collection in In-Vitro Culture: Evaluating The Impact of Sample Bags and Hydrogen Peroxide Pre-Sterilization

This study investigates sustainable leaf sample collection protocols for in-vitro culture (IVC) of chili (Capsicum frutescens) and tomato (Solanum lycopersicum) leaves. The research aimed to enhance viability and reduce contamination of leaf explants by evaluating various types of sample bags and different concentrations of hydrogen peroxide (H2O2) pre-sterilization. Specifically, the study compared the effectiveness of normal sealed (NS) bags and vacuum-sealed (VS) bags, including high-action (VSH) and low-action (VSL) vacuum-sealed bags, alongside H2O2 pre-sterilization at various concentrations. Leaf samples were treated with ten different concentrations of H2O2 (5% to 50%) to assess their impact on necrosis and surface contamination over 72 hr. Results showed that higher H2O2 concentrations (above 30%) caused significant necrosis, while concentrations between 10% and 15% provided optimal pre-sterilization for both leaf types, effectively reducing contamination without excessive tissue damage. In the second phase, the research examined the influence of different sample bags on leaf explant sustainability. Vacuum-sealed bags, particularly those with low-action vacuum (VSL), significantly improved leaf longevity and minimized contaminant emergence compared to normal sealed bags. Combined with 15% H2O2 pre-sterilization, VSL bags performed best, maintaining leaf morphology and viability for extended periods. Statistical analyses confirmed the significant impact of sampling bag type and pre-sterilization on contamination levels, necrosis emergence, and leaf longevity. The findings suggest that using low-action vacuum-sealed bags (VSL) with 15% H2O2 pre-sterilization is a promising approach for sustainable leaf sample collection, enhancing the success rate of IVC by minimizing microbial contamination and preserving leaf integrity during transport. This optimized protocol offers valuable insights for researchers and practitioners in plant tissue culture and agriculture, aiming to improve the sustainability and efficiency of leaf sample collection for in-vitro applications.

Prediction of olive tuberculosis through physicochemical characterisation of Pseudomonas savastanoi and surfaces of different olive tree parts

ABSTRACT This study examined plant–microbe interactions and surface contamination of olive trees by Pseudomonas savastanoi pv. savastanoi, the pathogen causing olive tuberculosis. Using XDLVO theory, we assessed the theoretical adhesion of P. savastanoi B97 cells to the bark, upper, and lower leaf surfaces of four olive cultivars based on physicochemical properties. Contact angle measurements revealed that lower leaf surfaces were more hydrophobic than upper leaf and bark surfaces, with a stronger electron donor character observed on the latter two. Lower leaf surfaces were identified as the preferred site for bacterial adhesion because of higher hydrophobicity. Among the cultivars, Arbicuina DOC and Arbicuina were most susceptible to colonisation. Conversely, cultivars with lower hydrophobicity and stronger electron donor properties, such as Haouzia and Moroccan Picholine, demonstrated greater resistance. These findings suggest that evaluating these properties can inform disease control strategies, promoting sustainable agriculture through resistant cultivars or targeted management of vulnerable surfaces.

The impact of enhanced cleaning on bacterial contamination of the hospital environmental surfaces: a clinical trial in critical care unit in an Egyptian hospital.

Contaminated environmental surfaces play an important role in the transmission of pathogens that cause healthcare acquired infection (HAI). The present study aimed to assess the effect of enhanced cleaning techniques on bacterial contamination in high-touch areas compared to routine cleaning at the intensive care units (ICU) of the neurosurgery department of Alexandria Main University Hospital, Egypt. The assessment of the knowledge and practices of healthcare cleaning workers and nurses was conducted through a questionnaire and an observational checklist. An educational program about enhanced cleaning was carried out for healthcare cleaning workers and nurses in one room of the ICU unit. Environmental surface swabs were taken from the two rooms of the ICU before and after cleaning (room A and room B). Room A was selected to apply the enhanced cleaning, and room B was selected for routine cleaning. A significant decrease in bacterial counts in the high-touch areas around the patients after the application of enhanced cleaning compared to routine cleaning (p < 0.001) was observed. Gram-negative bacteria isolated from high-touch areas accounted for 45.6% of the samples collected before enhanced cleaning, and they became 16.3% after enhanced cleaning (p < 0.001), while they accounted for 40% after routine cleaning. The enhanced cleaning intervention in Room A resulted in a significant reduction in total infections, decreasing from 18 cases in the six months prior to the intervention to 11 cases in the six months following its implementation. (p < 0.05). The effect of enhanced cleaning was evident in decreasing bacterial counts in the high-touch areas around the patient and consequently in the records of the HAI rate inside the ICU. PACTR202402531001186, date: 15 February 2024, 'retrospectively registered'.

Faucets and keyboards as a major reservoir of gram-negative bacilli in a regional hospital in Northeast Brazil

Infections related to healthcare assistance represent a major public health problem worldwide, and the main etiological agents associated with these infections are microorganisms also found on inanimate hospital surfaces. Therefore, understanding the dynamics of bacterial contamination of hospital surfaces is essential for professionals working in these services. Objective: To evaluate the contamination of inanimate surfaces by Gram-negative bacilli (GNB) in a Regional Hospital in Northeast Brazil. Methods: This is an observational and cross-sectional study. Samples were collected from different hospital wards using a sterile swab soaked in saline solution. They were then plated on MacConkey agar and incubated at 36°C for 48 hours. The bacterial isolates were counted and identified using the Gram staining method, TSI agar, and oxidase test. Results: Out of the 150 samples collected, 71 showed no microbiological growth, 11 showed growth of filamentous fungi, and 66 showed growth of Colony Forming Units (CFU). A total of 132 morphologically distinct colonies were identified, with 55 identified as yeasts and 77 as GNB. In the evaluation of hospital wards, the Adult Emergency Room and the Orthopedic Surgical Clinic showed the highest growth of GNB. Regarding the surfaces studied, the most contaminated were faucets, computer keyboards, mattresses, and beds. Conclusions: Hospital areas with higher human traffic are the most contaminated, particularly on frequently handled objects. Therefore, it is necessary to focus on disinfecting these surfaces to break the transmission chain of these etiological agents.

Development of α-ray visualization survey meter in high gamma and neutron background environment.

A survey meter was developed to reliably detect and visualize surface contamination of suits and objects by α-nuclides in high γ/n-rays background radiation environment. The survey meter features a semi-opaque ZnS:Ag scintillator mounted directly onto a multi-anode photomultiplier tube (MA-PMT) and amplification circuits, ensuring output gain equalization for all channels. α-ray events induce localized light emission in thin-film scintillators. By directly mounting the scintillator, diffusion of light before reaching the MA-PMT is suppressed, concentrating it in just a few channels, thereby facilitating discrimination from background radiation. This design also enables clear visualization of the shape of surface contamination. The prototyped survey meter is capable of responding up to 2.1×107cpm, with no γ-ray response even in high-radiation environments exceeding 1Sv/h. In actual environments with high background radiation, contamination of ~1/100th of the surface contamination density limit of 4Bq/cm2 could be reliably detected.

Infrared Thermography of Turbulence Patterns of Operational Wind Turbine Rotor Blades Supported With High‐Resolution Photography: KI‐VISIR Dataset

ABSTRACTWith increasing wind energy capacity and installation of wind turbines, new inspection techniques are being explored to examine wind turbine rotor blades, especially during operation. A common result of surface damage phenomena (such as leading edge erosion) is the premature transition of laminar to turbulent flow on the surface of rotor blades. In the KI‐VISIR (Künstliche Intelligenz Visuell und Infrarot Thermografie—Artificial Intelligence‐Visual and Infrared Thermography) project, infrared thermography is used as an inspection tool to capture so‐called thermal turbulence patterns (TTPs) that result from such surface contamination or damage. To complement the thermographic inspections, high‐resolution photography is performed to visualise, in detail, the sites where these turbulence patterns initiate. A convolutional neural network (CNN) was developed and used to detect and localise turbulence patterns. A unique dataset combining the thermograms and visual images of operational wind turbine rotor blades has been provided, along with the simplified annotations for the turbulence patterns. Additional tools are available to allow users to use the data requiring only basic Python programming skills.

Enhanced removal of fluoride ions using lanthanum-doped coconut shell biochar in PVDF ultrafiltration membranes

Fluoride contamination in surface and ground water poses significant health risks, necessitating a low-energy, cost-effective removal method. Herein, an ultrafiltration (UF) adsorptive membrane doped with lanthanum (La)-based coconut shell biochar was synthesized to effectively remove fluoride ions. Based on the results of adsorption and membrane separation performance, it was found that La-based biochar showed a significantly higher adsorption capacity (126.7 mg F/g) compared to bare biochar (27.41 mg F/g), due to the oxygen-containing functional groups from La2O2CO3 that enhance binding sites and electrostatic attraction for fluoride ions. Furthermore, the addition of La-modified adsorbent to the polyvinylidene fluoride (PVDF) UF membrane markedly altered its structure and surface properties, changing the pore structure to porous, narrowing pore size, increasing active adsorption sites, and improving hydrophilicity. These changes boosted fluoride ion rejection from 9.53 % to 62.07 % with tiny effect on membrane permeability. More important, this UF adsorptive membrane exhibited excellent antifouling ability with the lowest flux decline (J/J0 =0.450) compared to pristine PVDF membrane (J/J0 =0.142), which was owing to the better improved surface properties. In all, this study provides a novel strategy for efficient, economic and selective separation of fluoride ions and further extends the application of UF to the field of ion removal.

Cleaning and Disinfection of Surfaces in a COVID-19 Respiratory Syndrome Unit: A Quasi-Experimental Study

Objective: This study aimed to assess the impact of an educational intervention on the cleaning and disinfection processes within a respiratory syndrome unit, serving as a designated facility for COVID-19 patients. Methods: A quasi-experimental design was employed, incorporating a pre-intervention and postintervention assessment. The evaluation of surfaces involved various monitoring techniques, including Adenosine Triphosphate (ATP) testing, colony-forming unit analysis, and visual inspections. All statistical analyses were conducted at a significance level of 5% (p &lt; 0.05). Results: Following the implementation of the educational intervention, a notable reduction in surface contamination rates was observed. Significant improvements were noted for specific surfaces when utilizing the ATP testing method, including benchtops (p = 0.030), mattresses (p = 0.014), doorknobs (p = 0.014), and armchairs (p = 0.014). Furthermore, a decrease in the total count of aerobic bacteria was observed for benchtops (p = 0.014), mattresses (p = 0.014), and doorknobs (p = 0.014). Visual inspection results also indicated enhancements, with approval rates for benchtops, armchairs, and mattresses rising from 0% before the intervention to 37.5% afterward. Conclusion: The findings of this study demonstrate substantial improvements in approval rates following the implementation of the educational intervention. Additionally, this research provides valuable insights for the development of ongoing educational initiatives for the healthcare team, incorporating evaluation and feedback mechanisms as well as updates to cleaning and disinfection protocols.

Studying the Photoactivity of Ag-Decorated TiO2 Nanotubes with Combined AFM and Raman Spectroscopy

The drive for the development of systems that can simultaneously investigate chemical and morphological information comes from the requisite to fully understand the structure and chemical reactivity relationships of materials. This is particularly relevant in photocatalysis, a field ruled by surface interactions. An in-depth understanding of these complex interactions could lead to significant improvements in materials design, and consequently, in photocatalytic performances. Here, we present a first approach to a combined atomic force microscopy (AFM) and Raman spectroscopy characterization of anodic TiO2 nanotubes arrays decorated with Ag nanoparticle electrodeposition from either the same anodizing organic electrolyte or from an aqueous one. Photocatalytic substrates were used in up to 15 consecutive photocatalysis tests to prove their possible deterioration with reuse. Sample aging can, in principle, produce changes in both the morphology and the chemical compounds that characterize the photocatalyst surface. Adopting multiple characterization techniques, such as a combination of AFM and Raman spectroscopy in an original setup, can profitably enable the observation of surface contamination. A significant drop in photocatalytic activity was observed after 10 cycles on samples where silver was deposited from the organic electrolyte, while the others remained stable. Such a drop was ascribed to photocatalyst deactivation. While in other cases, a simple recovery treatment allowed the initial photoactivity to be restored, this deactivation was not restored even after chemical and thermal cleaning treatments.

Ablation treatment of CFRP via nanosecond pulsed Ytterbium-doped fiber laser: Effects of process parameters on surface morphology and shear strength of adhesive bonded joints

Adhesive bonding is the joining technique that provides the maximum exploitation of Carbon Fiber Reinforced Polymers (CFRPs) for structural applications. However, it is necessary to attain a high-strength adhesive bond, achieved by removing surface contaminants, such as mold release agents, and simultaneously generating a surface structure suitable to increase the actual contact surface area. The purpose of the research work presented in this paper is to evaluate the effect of process parameters of a nanosecond pulsed laser pre-bonding surface treatment on the ablation of thermoset matrix CFRP substrates. In particular, the link between the volume of ablated material and the tensile shear strength (TSS) of adhesive bonded joints was evaluated by lap-shear tests, profilometer surveys, and Scanning Electron Microscope (SEM) analysis. ANOVA and regression models were used to highlight the influence of laser parameters, with power emerging as the most significant factor, and energy density proving pivotal for joint strength. Line spacing was also significant, while scanning direction had negligible impact. The key outcomes of the study demonstrated that controlled laser ablation plays a critical role in determining joint performance. A negative correlation was found between TSS and the thickness of ablated material, indicating that excessive ablation weakens the bond. Optimal joint strength was achieved with moderate fiber exposure while maintaining matrix integrity, emphasizing the need for precise control over laser parameters. Fracture surface analyses revealed distinct failure mechanisms, ranging from cohesive failure within the adhesive layer to interfacial failure at the fiber-matrix boundary, depending on the ablation conditions. The findings provide clear guidelines for optimizing laser surface treatments to enhance the structural performance of CFRP adhesive joints in practical applications.

Detection of β-ray from 3H with back illuminated sCMOS imager

Tritium occurs in nuclear power plants. The energy of beta-rays from tritium is so low that detecting the beta-rays is challenging. Therefore, method of measuring tritium surface contamination is required. Liquid scintillators are generally used to measure the beta-rays. However, this method is complicated to use on-site. To measure tritium surface contamination on-site, we attempted to detect tritium using the GSENSE2020BSI back-illuminated sCMOS imager.We used a tritium areal radiation source to validate the detection of beta rays from tritium. The beta-rays cause bright spots in images and spread to multipixel. The average number of the pixels by the beta-rays was 4.6 and covered within a 3x3 pixel region. The energy spectrum from 10,000 images with 3x3 binning patterns showed a continuous shape spectrum. The spectra shape was characteristic of beta-ray spectra, demonstrating that the energy spectrum could be obtained with low-energy beta rays from tritium using the back-illuminated sCMOS image sensor. The spectral shape was produced from a radiation simulation using Geant4. From the simulation, the sCMOS sensor was able to measure tritium contamination of 10 becquerels (Bq)/cm2 within 100 s and 4 Bq/cm2 within 480 s.

Multifunctional Smart Fabrics with Integration of Self-Cleaning, Energy Harvesting, and Thermal Management Properties.

Due to their good wearability, smart fabrics have gradually developed into one of the important components of multifunctional flexible electronics. Nevertheless, function integration is typically accomplished through the intricate stacking of diverse modules, which inevitably compromises comfort and elevates processing complexities. The integration of these discrete functional modules into a unified design for smart fabrics represents a superior solution. Here, we put forward a rational approach to functional integration for the typical challenges of thermal management, energy supply, and surface contamination in smart fabrics. This sandwich-structured multilayer fabric (MLF) is obtained by continuous electrospinning of two layer P(VDF-HFP) fabric and one layer P(VDF-HFP) fabric functionalized with core-shell SiO2/ZnO/ZIF-8 (SZZ) nanoparticles. Specifically, MLFs achieve effective and stable energy harvesting in triboelectric nanogenerators (TENGs) with hydrophobicity and antibacterial properties. Meanwhile, MLFs also have high mid-infrared emissivity and sunlight reflectivity, successfully realizing radiative cooling under different climates, and have been applied in wearing clothing, roof shading, and car covers. This work may contribute to the design and manufacturing of next-generation thermal comfort smart fabrics and wearable electronics, particularly in terms of the rational design of multifunctional devices.

Development of a method for evaluating fabric surface contamination by particulate matter using fluorescent particles

Functional clothing products are being developed to prevent the attachment of particulate matter (PM). However, currently, PM-blocking performance of such products cannot be quantitatively evaluated. This study developed a method for measuring fabric surface contamination by PM by contaminating textile fabrics with PM and using an image processing technique. Silicate particles exhibiting fluorescence characteristics with a suitable size distribution were selected as PM simulants. The fabric surface contamination was calculated by contaminating textile fabrics under wind speed and PM concentration conditions similar to actual atmospheric environment. The number of pixels was obtained in the black and white binary images converted from the images of the textile fabrics captured under an ultraviolet (UV) light source. Experiments were performed using finished nylon fabric with PM-blocking performance and raw nylon fabric without PM-blocking performance. Comparison of the fabric surface contamination shows that it is possible to evaluate the PM-blocking performance of fabrics.

In-situ detection of high-energy beta ray emitter 90Sr/90Y inside the Fukushima Daiichi Nuclear Power Station Unit 3 reactor building using a liquid light guide Cherenkov counter

We have developed a method to directly detect 90Sr/90Y under a high gamma ray background using a liquid light guide Cherenkov counter. Cherenkov radiation has the characteristic that the angle of radiation varies depending on the energy of the charged particles. Using this feature, we have developed a surface contamination detector capable of discriminating between 662 keV gamma rays from 137Cs and beta rays from 90Sr/90Y through time-of-flight analysis of the Cherenkov radiation generated inside the liquid light guide. With this detector, we conducted a measurement test of 90Sr/90Y inside the Fukushima Daiichi Nuclear Power Station Unit 3 reactor building and achieved the first in-situ detection of 90Sr/90Y under a high gamma-ray background.