Stable reference electrodes (REs) are crucial for reliable voltammetry, controlled potential electrosynthesis, or spectro‐electrochemistry. Yet, inferior pseudo‐REs, such as plain Ag wire are often ...used, because commercial REs are expensive, may degrade or contaminate under required conditions, or don't fit geometric restrictions of custom setups. Addressing such cases, we report construction, benchmarking and utilization of easy to make, cheap (<1 €), and robust miniature REs from pasteur pipettes, molecular sieve beads and Ag wire. Excellent potential precision and accuracy with at least 1 week device stability was obtained for aqueous Ag/AgCl REs with 3 M NaCl in H2O and anhydrous 0.1 M TBACl in MeCN inner‐electrolytes. Even in alkaline 1 M NaOH electrolyte, where initial Ag/AgCl REs quickly convert to Ag/Ag2O (1 M NaOH) REs, perfect potential precision, accuracy, and at least 1 week stability are demonstrated. According to experimental needs, miniature REs can be built with many organic and aqueous electrolytes. For these custom use‐cases, we report guidelines to calibrate absolute RE potential, and to assess device precision, accuracy and stability. Finally, electro‐hydrogenation of styrene on nickel electrodes exemplifies superiority of Ag/AgCl REs over Ag wire pseudo‐REs, affording more reliable electrolysis current, cell potential and potential dependent Faraday efficiency.
Cheap and simple Ag/AgCl reference electrodes for aqueous and organic electrolyte: An Ag/AgCl RE in robust glass casing can be home‐made in minutes for less than 1 €. Reliable use in aqueous and organic electrolytes is shown for CV and exemplary electro‐hydrogenation of styrene by controlled potential electrolysis. RE potential stability is confirmed for at least 1 week in multiple organic and aqueous electrolytes, including NaOH solutions at pH=14.
Detector developments for high performance Muography applications Varga, D.; Nyitrai, G.; Hamar, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Letnik:
958
Journal Article
Recenzirano
Muography allows imaging of large scale objects using cosmic muons. As the observation point needs to be below the object of interest, either the detector is placed underground, and can reveal ...density structures, or, the detector can be on the surface and look sideways, capturing muons closer to the horizon.
As the measurement time is fundamentally limited by the muon flux, long term operation must be achieved with high efficiency. Furthermore, reasonable imaging from a large distance requires good angular resolution. The relevance of addressing the out-of-laboratory environment is demonstrated on the example of a 4 square metre telescope targeting the Sakurajima volcano in Japan.
For open air detectors, the suppression of the low energy (non penetrating) muon background can be reached with a telescope using absorber (scatterer) layers between detector layers with good position resolution. The presented Muography Observation System achieves that using MWPC-s, combined with the relevant servicing systems providing reliable power and gas supply, as well as data acquisition and transfer.
Muography is a novel imaging technology based on particle physics instrumentation to reveal density structure of hill-sized objects. The cosmic muon flux is attenuated while penetrating into the ...ground, thus the differential local flux correlates with the overburden density-length. Underground muography exploits the close-to-zenith flux, while main challenges became portability, low power consumption, and robustness against the out-of-the-laboratory environment. Various fields could benefit from this non-invasive imaging, eg. speleology, mining, archeology, or industry. Portable gaseous tracking detector systems have been designed, built, and successfully used in several underground locations. This paper presents the designed portable muography systems, the main requirements, and measurement campaigns for calibration, natural caves, and cultural heritage.
Abstract Background and aims Some crucial associations between obesity-related altered adipokine levels and the main factors of atherosclerotic, atherothrombotic processes are not fully known. We ...analysed the relationships of classic adipokines, namely leptin, resistin, adiponectin, tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6) with the markers of platelet activation, including mean platelet volume (MPV), platelet surface/soluble P-selectin, platelet-derived microparticles (PMPs), the parameters of coagulation abnormalities and common carotid intima-media thickness (IMT) in obese patients with or without atherosclerotic comorbidities in comparison to age- and sex-matched controls. Methods and results We enrolled 154 obese individuals, including 98 suffering from atherosclerotic concomitant conditions, 56 free of atherosclerotic comorbidities and 62 healthy controls. Plasma levels of leptin, resistin, adiponectin, TNF-α, IL-6, soluble P-selectin, and plasminogen activator inhibitor-1 antigen (PAI-1 ag) were analysed by ELISA. Platelet surface P-selectin and PMPs were measured by flow cytometry. IMT was detected by ultrasonography. Adipokines were closely associated with markers of platelet hyperactivity, hypercoagulability, hypofibrinolysis and IMT. Significant independent associations were found between leptin and platelet count (p<0.0001), MPV (p=0.019), PMPs (p<0.0001), fibrinogen (p=0.001), factor VIII (FVIII) activity (p=0.035); adiponectin and PAI-1 ag (p=0.035); resistin and soluble P-selectin (p=0.002); TNF-α and PAI-1 ag (p<0.0001); and IL-6 and fibrinogen (p=0.011). Finally, leptin (p=0.0005), adiponectin (p=0.019), IL-6 (p=0.001), MPV (p=0.0003), PMP (p=0.008), and FVIII activity (p=0.043) were independent predictors of IMT. Conclusion Overall, we suggest that in obese subjects altered adipokine levels play a key role in common carotid atherosclerosis both directly and through haemostatic parameters.
Muography is a novel imaging technology to reveal density structure of hill-sized objects. The cosmic muons predictably lose their energy and penetrate hundreds of meters into the ground, thus their ...differential local flux correlates with the crossed density-length. The Sakurajima Muography Observatory in Kagoshima, Japan, is the largest muography experiment targeting an active volcano. A set of multilayered gaseous detectors are used to reconstruct the muon tracks, thus by measuring the flux, imaging of the inner part of the volcano become possible. The paper focuses on the technical challenges of such a particle tracking system, the designed multi-wire proportional chambers, and the recent results from the measurements.
Muography is a well established method to obtain 3D images of large objects (e.g. volcanoes and large buildings) without any additional particle source, taking advantage of the presence of cosmic ...muons. The underlying principle of muography is the measurement of individual muon tracks and the determination of their absorption or scattering. These processes depend on the material that they have travelled through. The novel method discussed is based on the measurement of the muon tracks and of the corresponding particles that were produced by the muons themselves in the investigated target. As muons pass through matter they interact with matter by ionization, bremsstrahlung, pair production and nuclear interactions. Our experimental setup is designed in a way to measure both the primary muons and the created secondaries (mostly electrons and gammas). The tracks of the muons are determined by a special kind of Multi-Wire Proportional Chambers (MWPC) called CCC (Close Cathode Chamber). The secondary particles produced in the target are measured by four plastic scintillators placed around the target. The CCC chambers and the scintillators are used in coincidence in order to gather data about muons that passed through the target. As cross sections of the described processes vary by the density and the atomic number of materials this technique could be used to investigate the material content of the target.
Muography is an efficient tool to study the internal structure of large objects, exploiting the large penetration length of the naturally produced cosmic muons. The instrumentation required for this ...application is derived, but has distinct differences, from those in high energy and particle physics. The paper below presents the case example of the Sakurajima Muography Observatory (SMO), which is the world's largest volcano-targeting tracking system. The discussion addresses some of the problems related to the installation and maintenace of gaseous detectors on the field. As muography observations rely on assumptions on terrain, muon flux related to material density length, and smearing by scattering effects, an interesting study was conducted to experimentally demonstrate the possibility of imaging through a thick material. In this case, the ridge of a background hill can be identified behind 100 m rock in foreground.
A portable cosmic muon detector has been developed for geophysical applications: searching for large scale underground rock/soil inhomogeneities and underground cavities. The designed muon telescope ...called a muon tomograph is based on the recently developed closed cathode chamber (CCC) technology, which provides a cheap, easy handling, portable, and power efficient detector system able to work even in extreme conditions (e.g. high humidity, low/high temperature). The muon telescope has a detection surface of approximately 0.1 m2 with a 10 mrad angular resolution. Tests have been performed in natural caves and artificial tunnel systems as well. In this paper a summary of the first results on tomographic cavities are presented and the geophysical and possible industrial use of the cosmic muon tomographic technology is indicated.
A portable cosmic particle tracking detector has been developed by the REGARD group with angular resolution of 10 mrad. The Close Cathode Chamber-based tracking system is optimized for environmental ...and geophysical applications with its weight of 15 kg and size of 51 cm × 43 cm × 32 cm. Our aim was to determine the cosmic background at the site of the proposed accelerator and experimental facilities at an approximate 50 meter depth in Felsenkeller, Dresden, Germany. Here, we present our high-precision muon flux measurements, which have been performed during 44 days in one of the tunnels. Angular acceptance of our mapping covered full 2π solid angle of the upper hemisphere. The maximum flux value is found to be below 2.5 m-2sr-1s-1.
This paper presents the Forward Time Projection Chamber (FTPC) system of the NA61/SHINE experiment at the CERN SPS accelerator. This TPC system applies a novel tandem-TPC design to reduce the ...background originating from particle tracks not synchronous with the event trigger. The FTPC system is composed of three chambers with alternating drift field directions. The chambers were installed directly along the beamline region of the NA61/SHINE detector in a medium- to high-intensity (10−100kHz) hadron or ion beam. The tandem TPC system has proved to be capable of rejecting out-of-time background tracks not associated with a primary interaction. In addition, the system performs tracking and inclusive dE/dx particle identification for particles at and near the beam momentum. This shows that a tandem-TPC-based chamber design may be used also in other experimental applications with a demand for low material budget, tracking capability, and the need for dE/dx particle identification, all while in the presence of a relatively high particle flux.
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